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APPLETON’S 
 
 DICTIONARY 
 
 AND 
 
 ENGINEERING. 
 
 ILLUSTRATED WITH FOUR THOUSAND ENGRAVINGS ON WOOD. 
 
 IN TWO VOLUMES. 
 
 VOL. XX. 
 
 NTGNV EDITION, WITH APPENDIX 
 
 NEW Y 0 R Iv : 
 
 TV. APPLETON & COMPANY, 
 549 & 551 BROADWAY. 
 
 1 8 7 4. 
 
Entered, according to Act of Congress, in tlie year 1851, by 
 D. APPLETON & CO., 
 
 In the Clerk’s Office of the District Court of the United States for the Southern 
 District of New York. 
 
 Entered, according to Act of Congress, in the year 1868, by 
 D. APPLETON & CO., 
 
 In the Clerk’s Office of the District Court of the United States for the Southern 
 District of New York. 
 
A DICTIONARY 
 
 OF 
 
 MACHINES, MECHANICS, ENGINE-WORK, 
 AND ENGINEERING. 
 
 HACKLE or LIAX. A kind of comb or brush made of iron spikes ; used for combing or pulling tli« 
 fibres of wool or flax, so as to reduce them from a tangled to a smooth state. 
 
 HADE. In mining, the underlay or inclination of the vein. 
 
 HALF-TIMBERED HOU SES. Buildings in which the foundations and principal supports were 0 / 
 stout timber, and the interstices of the fronts were filled with plaster. 
 
 HALLIARDS. In navigation, the ropes or tackles usually employed to hoist or lower any sail. 
 
 HAMMER. A well known carpenter’s tool, Fig. 2243 represents a modification 
 known as Anderson's Patent Hammer. In this hammer, the claw, as will be seen by 
 the cut, extends to the handle and clasps it with a strong ring, which makes 
 it impossible, in drawing nails, for the handle to give way, draw out, or become 
 loose. The face of the patent hammer w 7 ill thus always remain true, it being 
 kept at the same angle with the handle. Six different sizes are now made, 
 weighing from half a pound to one and a half pounds* 
 
 HAMMER, steam. James Nasmyth’s patent steam-hammer. Before pro- 
 ceeding to describe the principle, mode of action, and constructive details of the 
 direct-action steam-hammer, it may be proper to make a few remarks on the 
 ordinary forge-hammers, so that the nature of the advantages possessed by the 
 steam-hammer may be more clearly understood. 
 
 In all forge-hammers previously in use, the force necessary to set them into operation had to be 
 transmitted in a very indirect manner, — for whether a water-wheel or steam-engine w'ere the moving 
 power, the requisite lifting and falling action of the hammer had to be produced by the employment of 
 rotatory motion, thus rendering necessary the use of wheels, shafts, cams, and other cumbrous details, 
 which, together with the apparatus requisite to connect the various parts of the machinery, and give due 
 strength and solidity to the whole, not only caused great outlay and sacrifice of valuable space, but 
 also occasioned much loss of power, by reason of the very circuitous manner in which the force of the 
 prime moving agent had to travel ere it reached its final destination, and came forth in blows from the 
 forge-hammer. Great inconvenience, also, was found to result from having a considerable portion of the 
 working machinery close to the hammer, as thereby a very serious impediment was offered to the free 
 execution of the work. And when we add to this very limited range in the clear fall of an ordinary 
 forge-hammer, (seldom, in any case, exceeding 18 inches,) causing the force of the vlow to decrease in a 
 very rapid ratio, with a moderate increase in the diameter or depth of the work ; and when we take 
 into consideration the fact that, in consequence of the helve of the hammer working on a centre or joint, 
 its face is parallel to that of the anvil only at one particular distance ; and finally, when to this list of 
 inconveniences we add that in the ordinary forge-hammer we possess no power or control over the force 
 of its blows, but are compelled to make the best use y/e can of them, whether they be adapted to our 
 purpose at the time or otherwise, we find inherent in the very principle of such hammers, a combina- 
 tion of evils and inconveniences that only excite surprise that they should have been suffered to exist 
 for so great a length of time. 
 
 This remark is most strikingly applicable in file case of those forge-hammers which receive their 
 power from a steam-engine, inasmuch as the power in question originates in the motion of the piston, 
 m the very state and condition in which, for the purpose of hammering, we desire it ultimately to be, 
 namely, as a straight up and down motion ; so that instead of causing this reciprocating action of the 
 piston-rod to pass through all the complex media of beam, connecting-rod, crank and cam shaft, for no 
 
4 
 
 HAMMER. 
 
 other purpose than to cause it to act in the same manner as at first,— if we dispense with all this mas* 
 of intermediate machinery, and simply invert the steam cylinder so as to bring its piston-rod out at tbs 
 bottom of the cylinder, and attach it directly to a block of iron working in guides right over the anvii 
 
HAMMER. 
 
 3 
 
 Some idea of its efficiency in shingling puddled balls may be formed from the fact, that one of 3C 
 rwt., which has been for nearly two years in constant operation at the Gartness Works of the Monkland 
 Iron Company, in the West of Scotland, works off with perfect ease the constant produce of from 18 to 
 20 puddling furnaces. For this duty the steam-hammer is found to be peculiarly adapted, as it can be 
 made to act for the first few strokes as a squeezer, to bring the puddled ball to a neat cubical form ; 
 after which it may be made to deal out upon it such energetic blows as secures the entire expulsion of 
 all cinder and other non-metallic impurities, the absence of which, to a greater or less extent, mainly 
 determines the quality of wrought-iron. In short, in every process where either blows of the most 
 enormous energy, or slight taps of {lie utmost gentleness are required, either continuously or in all 
 grades of variation from the one extreme to the other, the steam-hammer offers facilities which have 
 never hitherto been obtained from any mechanical contrivance for such purposes. 
 
 Fig. 2244 represents a side elevation of the steam-hammer, exhibited in full operation, the hammer 
 block, valve-geer, and other working parts being disposed in the positions which they occupy at the 
 termination of a stroke. Fig. 2245 is a general plan corresponding to the above. 
 
 Fig. 2246 is an end elevation, and Fig. 224*7 a vertical transverse section of the machine. 
 
 Fig. 2248 is a sectional elevation of a portion of the machine, showing the positions of the hammer- 
 block, valve-geer, and other working parts when the hammer is raised for a fresh stroke. 
 
 The framing of the steam-hammer consists of two strong cast-iron standards A A, bolted and further 
 secured by keys to a broad base-plate B B, embedded in the solid masonry forming part of the floor of 
 the forge. The standards are surmounted, and their upper extremities united by a species of entabla- 
 ture C, in which the steam-passages and valve-face are formed, and to the upper surface of which the 
 steam cylinder D is bolted. The piston-rod E is fitted to work vertically through a stuffing-box in the 
 centre of this entablature, and its lower extremity is directly attached to the mass of cast-iron F, form- 
 ing the hammer-block, which is guided to a strictly vertical and rectilinear course by being made to 
 work freely in planed guides formed on the interior surfaces of the standards A A. The hammer a 
 itself is inserted into a dovetail recess in the bottom of the block F, where it is retained by wooden 
 packing and iron wedges ; while the anvil b is in a similar manner secured to the anvil-block G, which 
 is a mass of cast-iron of such weight as effectually to oppose, by its inertia, the momentum of the ham- 
 mer, and prevent the force of the blows from being dissipated. 
 
 Such are the main features of this machine ; from which it will be at once understood that, if we can 
 provide the means of rapidly raising the hammer-block to a sufficient elevation, and then as rapidly 
 letting it fall down upon, and so give a blow to the work placed upon the anvil, we have all that is 
 requisite to produce a forge-hammer in its simplest, and, at the same time, its most powerful and per 
 feet form. 
 
 The duty above adverted to, of raising the hammer-block, is performed by the direct application of 
 the elastic force of steam. For this purpose, the steam is led on to the machine by the steam-pipe H. 
 communicating with a neighboring high-pressure boiler ; a throttle, or shut-off valve c, inclosed within 
 the valve-box I, being situated close to its junction with the main steam-valve chest J, and brought 
 within the control of the attendant workman by means of the rod and lever eld. The alternate admis- 
 sion of the steam into the cylinder by the port/, and its escape therefrom by the passage g , and waste 
 steam-pipe K, are regulated by means of the slide-valve e, which may either be worked by hand, or, 
 through the intervention of the self-acting mechanism to be hereafter specified, by the action of the 
 machine itself. The piston L, which is strongly constructed of malleable iron, and fitted with a single 
 packing ring, works steam-tight within the cylinder D ; and being directly attached by the piston-rod 
 E to the hammer-block F, it will be obvious that, on the admission of steam of sufficient elastic force 
 beneath the piston, we are supplied with the means of raising the hammer-block to any required height 
 within the range of the machine ; while by opening the communication between the under side of the 
 piston and the external atmosphere, the action of gravity will be unimpeded, and the hammer will de- 
 scend upon the work placed on the anvil, and discharge a blow upon it, energetic in proportion to the 
 weight of the hammer-block, and the height from which it has fallen. 
 
 And as, by these simple means, there is no practical inconvenience in supplying the power to raise a 
 hammer-block of 5 or 6 tons weight to an elevation of *7 or 8 feet above the anvil, some idea may be 
 formed of the vast energy of the blows given out by such a mass of iron falling rapidly through so great 
 a space, and discharging the whole of its momentum upon the work placed below on the anvil to re- 
 ceive it. In the case of the old system of forge or helve hammers, about one-third only of the total 
 weight of the hammer was effective, the other two-thirds resting on the pivot-standards; so that, in this 
 point of view, the proportion between the blow of a steam-hammer and that of a helve-hammer is 
 nearly 3 to 1 in favor of the former. 
 
 It will be seen, further, that the anvil-face and hammer-face are at all times parallel to each other, 
 whatever be the height or distance between them. The practical value and importance of this prop- 
 erty, which is inherent in the principle of the steam-hammer, has been duly appreciated by all who 
 have had experience of the working of this machine. 
 
 With a view to prevent any risk of the piston striking the cylinder-cover when working to the full, 
 or veiy highest stroke of the hammer, a very simple but effective air or steam recoil spring is provided, 
 by having the cylinder-cover screwed down quite air-tight, so that as soon as the piston passes, in its 
 upward motion, the holes hh, the air or steam remaining above is shut up in the upper chamber; and 
 as it has no means of escape, it acts as a most perfect spring in arresting any further rise of the piston ; 
 and has, besides, the important advantage of converting into increased downward velocity of action the 
 undue upward action, which might otherwise have proved not only useless, but destructive. The in- 
 crease of energy in the blows which can be obtained by this simple, means is a point of considerable 
 importance. It is scarcely necessary to remark that, in the emergency above adverted to, the aper- 
 tures h h act as safety-valves for the issue of the main body of the steam, which escapes through th# 
 passage i i, into the exhaust or waste steam-pipe Iv. 
 
0 
 
 HAMMER 
 
HAMMER 
 
 Another point of constructive detail worthy of special notice is, the peculiar mode adopted for con- 
 necting the piston-rod to the hammer-block. This is one of the most important details in the entir* 
 invention, and without which no practical success would have attended it. Had the piston-rod 
 been attached to the hammer in the ordinary 
 mode of attaching pistons to the machinery of a 
 steam-engine or such like, namely, by a cotter, 
 or by screwing the rod into the hammer, or such 
 other solid, unyielding mode, the effect of the 
 blow or fall, at each stroke of the hammer, would 
 have been that the piston-rod and piston (being 
 composed of a considerable mass of materials) 
 would have themselves acted as a hammer, and 
 would have discharged their momentum upon 
 the means of fastening, and this with such de- 
 structive effect as to break through all such solid, 
 unyielding means of resistance, after a few blows. 
 
 This was foreseen from the first as an action 
 to be prevented, and accordingly, in my original 
 drawing, already adverted to, a remedy was pro- 
 vided, which experience has proved to be entirely 
 effectual. 
 
 This contrivance consists in placing, in a cylin- 
 drical recess formed in the body of the hammer- 
 block, and under the knob i, on the end of the 
 piston-rod, a series of pieces of hard wood, or 
 other slightly elastic material, as in Fig. 2246. 
 
 The effect of this arrangement is to allow the 
 momentum of the piston and piston-rod to de- 
 posit itself in such a comparatively gradual man- 
 ner as to cause the concussion arising from the 
 most severe and energetic blows of the hammer 
 to have not the slightest evil effects on the piston 
 and rod ; it is, in fact, the very same expedient 
 to which nature has had recourse for the pur- 
 pose of obviating those unpleasant and destruc- 
 tive shocks and vibrations which we should ex- 
 perience at every step or stamp of the foot, had 
 no cartilage been provided between the joints of 
 our bones. It is surprising to observe by how 
 small an amount of elasticity, from the employ- 
 ment of such compressible material, the evil 
 effect of violent shocks may be removed. The 
 connection of the piston-rod and hammer-block 
 is secured by means of the two keys k k, driven 
 very firmly above the knob or button j, a layer or 
 two of the elastic material being interposed for 
 the purpose of neutralizing any shock in the con- 
 trary direction. 
 
 We shall now proceed to describe the mechan- 
 ism by which the height of the fall of the ham 
 mer, and consequent intensity of the blow, may 
 be modified according to circumstances, and the 
 machine made perfectly self-acting. 
 
 The requisite alternating motion of the steam- 
 valve e is produced in the following manner : — 
 
 The valve-spindle l is prolonged upwards and 
 attached to a small solid piston m, working 
 within a short cylinder M, bolted to the main 
 steam cylinder D. A small portion of steam is 
 supplied above the piston m, by a slender copper 
 tube n, communicating with the steam valve- 
 chest J ; by this arrangement it will be seen 
 that, unless counteracted by some superior force, 
 the pressure of the steam upon the piston m will 
 tend to keep the valve e constantly depressed, 
 in which position the steam-port / is full open. 
 
 This counteracting force is supplied by the action 
 of the hammer itself; for, by means of the tap- 
 pet 1ST, (which is bolted to the hammer-block,) 
 coming into sliding contact, when the latter is 
 raised, with the small friction-roller o, mounted on the end of a bent lever 0 0, the screwed rod P 
 which is jointed to the opposite end of that lever, is depressed, and that motion being communicated to 
 the valve-spindle l, through the intervention of the oonnecting-rod Q and valve-lever R, the steam 
 
8 
 
 HAMMER. 
 
 valve e is raised, thus cutting off all further ingress of steam under the piston, and almost at the same 
 instant permitting the escape of that which had served to raise the hammer. By this simple contri- 
 vance the upward motion of the hammer is made the agent for its own control in that respect. By com- 
 paring the relative positions of the parts referred to, as exhibited in Figs. 2244 and 2248, the nature of 
 the motion above described will be at once most fully understood. To obviate the injurious effects oi 
 the shock of the tappet N against the lever 0, a connection is provided at p, on a similar principle to 
 that formerly described in reference to the connection of the piston-rod and the hammer-block ; and in 
 order to restrict the downward travel of the valve to the proper point, a check or buffer-box S is pro- 
 vided, consisting of a small cylinder bolted firmly to the framing of the machine, within which a circular 
 nut, screwed on the lower end of the rod P, works as a piston, a few leather washers being interposed 
 between the latter and the close or upper end of the cylinder. 
 
 It may be here remarked, that it is by no means necessary to continue the admission of steam under 
 the piston until the termination of the upward stroke, or lift of the hammer, seeing that the velocity 
 which the hammer-block has acquired in its upward motion makes it continue to ascend after the fur- 
 ther ingress of the steam has been arrested. This circumstance is a source of considerable economy of 
 steam, as we have by such action (as well as by that due to the expansive energy of the steam) an 
 effect as to height of lift of the hammer, greater than that which is due to the actual expenditure of 
 steam at its original pressure. It is worthy of remark, also, that as the over-running action above 
 alluded to will necessarily increase in proportion to the velocity of ascent of the hammer-block, this cir- 
 cumstance will, to a considerable extent, compensate for the increased expenditure of steam due to that 
 increased velocity. 
 
 From the above description it will be obvious, that the lift of 'the hammer, and consequent intensity 
 of the blows, depends simply upon the position of the lever 0, in relation to that of the hammer-block 
 when at its lowest point. Therefore, if we can provide the means of altering the distance between 
 these two points, we shall have it in our power to modify permanently the force of the blows to any 
 required extent within the range of the machine. This condition is most completely satisfied by the 
 arrangement of mechanism employed by me, and which is clearly represented in the figures. 
 
 The rod P which conveys the action of the lever O to the valve-lever R, is screwed throughout the 
 greater part of its length, and is so adjusted in its bearings, as to be susceptible of rotatory as well as 
 vertical motion. This motion of rotation is imparted to it by means of a handle fixed to a short axis, 
 working in a bracket T bolted to the framing, and actuating a pair of small bevel- wheels q q. The nut 
 through which the screw works forms the point of attachment between the rod P and the lever O, the 
 connection being effected by means of a short intermediate rod for the sake of insuring parallelism of 
 motion. A pair of small spur-wheels r r, (through the first of which the rod P works by means of a 
 sunk feather,) serve to transmit the angular motion of the rod P to a similar screwed-rod U, situated 
 parallel to and at a short distance from the former ; the nut of the screw U forms the fulcrum or centre 
 of motion of the lever O, and the pitch of the threads of both screws being equal, though formed in con- 
 trary directions to each other, it is obvious that, on turning the handle, the lever O and all its appen- 
 dages will be simultaneously raised or depressed, and consequently the lift of the hammer regulated to 
 any required extent, and its amount altered witli the utmost ease and precision. The pin which forms 
 the centre of motion of the lever 0 is protected and secured from lateral strains by the cast-iron guides 
 Y and W, seen most distinctly in the sectional plan, Fig. 2245. 
 
 A most essential part of the self-acting geer remains yet to be noticed. It is obvious that, were no 
 provision made for the retention of the steam-valve in the position into which it is thrown by the up- 
 ward motion of the hammer-block, the latter would not be permitted to have its due effect in the 
 accomplishment of its work ; for, as soon as it descended so far as to relieve the end of the lever 0 from 
 contact witli the tappet X, the valve would resume the position into which it is constantly solicited by 
 the action of the steam-spring at M, and the descent of the blow would be impeded by the return of the 
 steam into the cylinder, before the hammer had completed its fall. To obviate this inconvenience, a 
 simple but most effectual contrivance has been applied. Towards the lower extremity of the valve- 
 screw P a shoulder is formed, against which a short lever w, called the trigger, is constantly pressed by 
 the spring x, so that when the rod P is depressed by the action of the lever 0, it is arrested by the 
 trigger and retained in that position until the blow has been struck. This delicate and most important 
 part of the mechanism is very carefully constructed, the point of the trigger, and the shoulder against 
 which it acts, being formed oPsteel, and hardened to resist wear. 
 
 To release the valve-screw from the trigger, and so permit the return of the valve into the position 
 requisite for effecting a fresh stroke, the following mechanism has been adopted : on the front of the 
 hammer-block, Figs. 2244 and 2248, a lever X, called the latch-lever, is fitted to work freely on a pin 
 passing through the body of the hammer-block. That portion of the latch-lever which is most remote 
 from the valve-geer is considerably heavier than the opposite end, and is constantly pressed upwards 
 by means of a spring. The lighter end is brought into contact with a long bar s s, called the parallel 
 bar, the extremities of which are suspended upon two small bell-cranks 1 1, whose other arms are con 
 nected by means of a slender rod u. Fig 2247, forming a species of parallel motion, for the purpose of 
 adapting this geer to come into efficient operation, at whatever point in the range of the hammer its 
 blow may be arrested. A small connecting-rod v, between the lower bell-crank and a short lever on 
 the axis of the trigger w, completes this part of the mechanism. 
 
 The action of this geer is of a very peculiar nature, and is admirably adapted to fulfil the object in- 
 tended. At the instant the hammer gives a blow to the work upon the anvil, the effect of the concus- 
 sion is to cause the momentum of the heavy end of the lever X to overcome the upward pressure of the 
 spring, and thereby to protrude its opposite end against the edge of the parallel bar s, which motion, 
 though but slight in amount, is yet adequate, through the arrangements above described, to throw back 
 the trigger from contact with the valve-screw, and leave the latter free to obey the impulse of the steam- 
 spring in the readjustment of the valve into its original position. 
 
HAT-MAKING. 
 
 9 
 
 These various movements, which have taken so long to describe, are all performed in less than half 
 % second, and consequently the action of the hammer is proportionally rapid. 
 
 The construction of the self-acting geer is so arranged as to admit of advantage being taken, when 
 circumstances render it desirable, of the very action to obviate which the trigger w is introduced. WheD 
 it is desired to strike a gentle blow, such as is frequently required during particular stages in the prog- 
 ress of a piece of work, it is not requisite, for this purpose, to change the position of the valve-lever O. 
 All that has to be done is to hold back the point of the trigger w, by its handle y ; this permits the 
 valve to reopen and let the steam in under the piston L, at the instant the tappet N has fallen away 
 from contact with the lever 0. The effect of this is, that a quantity of steam is admitted into the cylin- 
 der under the piston, which serves as a cushion, by which the violent fall of the hammer is arrested, 
 and its momentum modified to any extent, or at the pleasure of the person in charge of the handles. 
 The handle 2 , is for the purpose of placing the steam-valve also under his control, and, for Iris further 
 convenience in the management of the hammer, a platform Y and hand-rail Z are erected against the 
 framing of the machine. 
 
 A modification of the frame of this machine has been made at the Washington Navy Yard, one sup- 
 port only being used, by which means access is had to the anvil on all sides except that occupied by 
 the support. 
 
 HAMMER, Tilt or Trip. See Tilting. 
 
 HARVESTER. An agricultural machine for reaping and gathering in grain, much used in the 
 western country. There are many forms of them, known in this part of the country as Reapers, 
 which see. 
 
 HAT-MAKING embraces two distinct kinds of manufacture, felted and covered hats ; the covering 
 of the latter being sometimes silk, and at other times cotton. 
 
 Felted hats comprehend two classes, differing chiefly in the materials used in making, the process 
 being nearly identical. The lower class is marked by inferior ingredients, unmixed with beaver, and 
 embraces wool, plated, and short-nap hats. 
 
 Wool hats are made entirely of coarse native wool and hair stiffened with glue. Plates have a nap 
 or pile rather finer than their body, and are sometimes water-proof stiffened. Short naps are distin- 
 guished from plates by additional kinds of wool, viz. hare’s back, seal, neuter, musquash, (Muscovy cat,) 
 and are all water-proof stiffened. 
 
 The second class may be said to comprehend two orders, called stuff and beaver hats. The first in- 
 cludes mottled and stuff bodies. The latter term is not used generally, as all stuffs are understood to 
 be of this sort when mottled is not expressed. Mottled bodies are made chiefly of fine wool, and inferior 
 rabbit down or coney wool. Stuff bodies consist of the best hare, Saxony, and red wools, mixed with 
 Cashmere hair and silk. Stuff hats are napped, that is, covered with pile of mixed seal, neuter, hare- 
 back, inferior beaver, and musquash. Beaver hats are, or ought to be, napped with beaver only ; the 
 lower priced qualities with brown wooms taken from the back ; the more valuable kinds with cheek and 
 white wooms, being the finest parts of the fur found on the belly and cheeks of the beaver. 
 
 The apparatus and terms used in making felted hats, which it is necessary to describe briefly, are the 
 bow, basket, hurdle, battery, and planks. 
 
 The bow is about six feet long, usually made of ash, thick enough not to be elastic. The handle is 
 called the stang. The bow-string is a strong catgut cord tensely fastened. 
 
 The hurdle is a fixed bench, with three enclosing sides, to prevent the stuff being flittered off in 
 bowing. 
 
 The basket is of light wicker-work, about twenty by twenty-two inches in size. 
 
 The battery consists of the kettle and the planks, which are inclined planes, usually eight in number, 
 one only being appropriated to each workman. The half of each plank next the kettle is lead, the 
 upper half is mahogany. 
 
 The first process in hat-making is bowing the stuff or furs, which are weighed out to a proportionate scale, 
 and laid on the hurdle, immediately under the bow, which is suspended by a pulley. The bow is held 
 firmly with the left hand, rather towards the breech-end, not edgewise, but on its side, with the string in 
 contact with the stuff, the clotted and adherent portions of which are separated into single fibres, and 
 attain a loose, flocky, mixed condition by the continued viiration of the bow-string, caused by a very rapid 
 succession of touches with the bow-stick. It is then divided as nearly as possible, and one-half laid aside, 
 whilst the other is again bowed. In this second operation, partly by the bowing, but chiefly by the gather- 
 big, or patting use of the basket, the stuff is loosely matted into a conical figure, about fifty by thirty-six 
 inches, called a bat. In this formation care is taken to work about two-thirds of the wools down to- 
 wards what is intended for the brim, which being effected, greater density is induced by gentle pressure 
 with the basket. It is then covered with a wettish linen cloth, upon which is laid the hardening skin. 
 a piece of dry half-tanned horse-hide. On this the workman presses or bakes for seven or eight 
 minutes, until the stuff shall have adhered closely to the damp cloth, in which it is then doubled up, 
 freely pressed with the hand, and laid aside. By this process, called basoning, (from a metal plate or 
 bason, used for like purposes in making wool hats,) the bat has become compactly felted and thinned 
 towards the sides and point. The other half of the flocked stuff is next subjected to precisely the same 
 proceedings, after which, a cone-shaped slip of stiff paper is laid on its surface, and the sides of the bat 
 folded over its edges to its form and size. It is then laid paper-side downward upon the first bat, 
 which is now replaced on the hurdle, and its edges transversely doubled over the introverted side-lays 
 of the second bat, thus giving equal thickness to the whole body. In this condition it is reintroduced 
 between folds of damp linen cloth, and again hardened, so as to unite both halves, the knitting together 
 of which is quickly effected. The paper is now withdrawn, and the body being folded into three plies, 
 is removed to the plank or battery-room. 
 
 In the battery the liquor is scalding heat, composed of pure soft water, with about half a gill of 
 nil of vitriol as an astringent. Herein the body is imbrued, and withdrawn to the plank to partly 
 
10 
 
 HAT-MAKING. 
 
 cool and drain, when it is unfolded, rolled gently with a pin tapering towards the ends like a liqnot 
 horse, turned, and worked with in every direction, to toughen, shrink, and at the same time prevent 
 adhesion of its sides. Stopping or thickening the thin spots which now appear on looking through the 
 body, is carefully performed, by additional stuff daubed on by successive supplies of the hot liquor 
 from a brush frequently dipped into the kettle, until the body be shrunk sufficiently, (about one-half,) 
 and thoroughly equalized. When quite dried, stiffening is performed with a brush dipped into a 
 glutinous pulpy composition, and rubbed into the body ; the surface intended for the inside having much 
 more imposed than the outer, while the brim is made to absorb many times the quantity applied to 
 any other part. This viscous matter contains proofing, or those ingredients which render the hat water- 
 proof. 
 
 On being again dried, the body is ready to be covered, and is once more taken to the battery. The 
 first cover of beaver or napping, which has been previously bowed, is equally strewed on the body, and 
 patted upon with the brush charged with the hot liquor, until incorporated ; the cut ends only being 
 the points which naturally intrude. Here the body is put into a coarse hair-cloth dipped and rolled in 
 the hot liquor, until the beaver is quite worked in. This is called rolling off, or ruffing. A stripe for 
 the brim round the edge of the inside, is treated in like manner, and is thus prepared for the second 
 cover, which is applied and inworked in like manner ; the rolling, &e., being continued until the whole 
 has become incorporated, and a clean, regular', close, and well-felted hood is the result. The dry hood, 
 after having the nap beat up and freed, is clipped to the length which may be thought best, by means 
 of common shears. A clipping machine, invented nearly four years ago in Scotland, is now very 
 generally preferred, and doubtless will soon everywhere supersede the ordinary process ; much greater 
 regularity, speed, and certainty being secured by it. When the nap is thus disposed of, the hood is 
 soaked in the battery kettle, and then drawn down on a block to the size and shape wanted, firmly tied 
 at the bottom with a cord, around which the brim is left in a frilled condition. 
 
 Dyeing is the next step. A suit, or six dozen, are put into the dye-kettle at a time, all on the crown- 
 blocks already mentioned, and allowed to remain three-quarters of an hour in the liquor, which is kept 
 as near as possible one degree below the boiling point. These being taken out and set in the yard to 
 cool, another suit is introduced for a like period, and the various suits are so treated at least twelve 
 times in successive order. Each of the first four introgressions of every suit is accompanied by about 
 seven pounds of copperas, and two pounds of verdigris. The body is then washed and brushed out in 
 changes of hot water, until no coloring can be recognized in it. When thus thoroughly cleansed, it is 
 steamed on a block shaped as the hat is wished to be when complete ; and in the finishing shop by 
 neavy (21 -pound) heated irons and moisture, the frilled brim is shrunk until rendered quite level, the 
 nap gently raised all over with a fine wire card, and brushed and ironed smooth in the uniform direc- 
 tions. The tip, a thin lath-sheet, is then fitted and stuck to the inside of the crown, and robbined or 
 secured all round the edges by stripes of prepared paper. When thus got down, it is sent to th e picker, 
 who, with tweezers, extracts the hemps, or “ gray hairs,” which are a few of those thick fibres peculiar 
 to the fur of amphibious animals, that have escaped the search of the machine used in blowing the 
 beaver, so as to separate them from its fine parts. This being carefully accomplished, it is transferred 
 to the finisher, who, with a plush cushion, a brush, and hot iron, imparts to it that bright sleeky 
 lustre. The shaper then rounds the brim with a knife and notched segment to the breadth wanted ; 
 and shapes it in varied styles by means of a hot iron and damp, with about a foot length of rope, 
 over which the curl is laid. The trimming is next done, when the tipper-off corrects the twists, 
 smooths the ruffled nap caused by trimming, and papers it up with tissue and cartridge, which com- 
 pletes it for the retailer. 
 
 Silk bats are made upon bodies of wool, stuff, willow, straw, and Leghorn plait, and cambric and 
 woollen cloth, although chiefly on felted wool bodies, which are dipped in glue size, wrung out, blocked, 
 and dried. The tipi is then fitted and robbined, when a flour-box, charged with powdered shell-lac and 
 rosin in like quantities, is used to strew equally its grainy mixture on the external surface of the shell, 
 so called from being the frame-work. This is burned in by hot irons, first on the top, which passes 
 through to the lath-tip within ; then on the upper brim, the sides, and, finally, the under brim. When 
 this is hardened it is coated with thick ordinary flour-paste, which is dried, and the shell again blocked 
 and smoothed ; then once more glue-sized outside, dried, and varnished, which prepares it for covering. 
 The shag for the sides is cut across the web, iu a ratio of obliquity increased by inferiority. This cross 
 part is sown to a circular piece for the crown, whilst the brims are singly patched together. These 
 preparations being completed, the top-side or upper brim is first stuck, then the crown, next the sides, 
 and, finally, the under brim. Sticking is effected simply by the heat of the iron passing through the 
 covering and melting the varnished surface. In the finish of this manufacture, the most particular part 
 is the side-seam, which is disposed of thus : The selvidge end is cut perpendicularly from top to brim, 
 by a sharpened pallet-knife, the nap having been previously brushed clear off its edge. The other 
 selvidge end is then stuck and cut with the utmost nicety, in close parallel with the other. It is then 
 finished very much in the same manner as a beaver hat. 
 
 The above-mentioned method of making hat-bodies is now mostly superseded in this part of the 
 country by the adoption of machinery, the manual labor being confined to the getting up the hat, and is 
 a distinct business ; the hatter for the most part purchasing his hat-bodies far cheaper than he can 
 make them. 
 
 The machinery is very simple. The fur or hair of which the felt is to be made, after being cleaned 
 and lightly beat up, by passing through a kind of winnowing machine, is delivered to a boy, who 
 spreads the fur very lightly and in small quantities on an endless web before him, which, passing between 
 rollers, carries the fur into the body of the machine, where it encounters a cylindrical brush in rapid 
 motion, which separates the hair or fur completely, throwing it towards a contracted opening in the 
 s'des of the cylinder-case. This opening, about an inch wide at top and nearly three inches at 
 bottom, is in height equal to the cone of the hat-body, Immediately in front, and close to this opening. 
 
HEAT. 
 
 11 
 
 is placed a perforated copper cone, the perforations so small, and in such number, as almost to render 
 the surface of the cone, from base to apex, a wire-gauze surface. This cone is open at the bottom and 
 placed on an opening equal to its base, which opening is in communication with a fan or blast, so ar- 
 ranged as to exhaust the interior, or “ suck,” so to speak, the air through the meshes of the copper cone. 
 The hair or fur in its divided state, thrown towards this opening in the cylinder case, is brought under 
 the influence of the powerful draught towards and through the cone ; the latter at the same time slowly- 
 revolving on its axis, exposes all its sides to the opening, and the hair is driven against it with such force 
 as to adhere for the time, and receive and retain on all sides, as it revolves, the fine particles of hair as 
 they are drawn from the cone. In the space of half a minute a dry hat-bodv is formed on the copper 
 cone ; this is immediately enveloped by a wetted felt, and the whole immediately removed, and its place 
 supplied by a fresh copper while the first is being stripped of its now wet felt. The whole operation is 
 performed with wonderful dispatch, the hat-body resulting from it being exceedingly light and uniform 
 in texture, and requires but little labor before it is in condition to be transferred to the hands of the 
 hatter for working up. In this manner any form of felt may be made. The opening in the cylinder 
 case being of flexible metal, admits of adjustment to the wants of the particular form of the felt to be 
 constructed. The application of this principle is universal in the manufacture of felt. 
 
 HEART -WHEEL. A cam for converting a uniform circular into a uniform rectilinear motion. 
 
 HEAT. Heat in the ordinai-y application of the word, implies the sensation experienced upon touching 
 a body hotter or of a higher temperature. Caloric , the principle or cause of the sensation of heat. On touch- 
 ing a hot body, caloric passes from it, and excites the feeling of warmth : when we touch a body having a 
 lower temperature than our hand, caloric passes from the hand to it, and thus arises the sensation of cold. 
 
 Caloric is usually treated of as if it were a material substance ; but, like light and electricity, its true 
 nature has yet to be determined. 
 
 Caloric passes through different bodies with different degrees of velocity. This has led to the division 
 of bodies into conductors and non-conductors of caloric : the former includes such bodies as metals which 
 allow caloric to pass freely through their substance, and the latter comprises those that do not give an 
 easy passage to it, such as stones, glass, wood, charcoal, &c. 
 
 Gold 
 
 Silver 
 
 Iron 
 
 Tin 
 
 Marble ... 
 Fire-brick 
 
 Table of the relative Conducting Power of different Bodies. 
 
 1000 
 
 Platinum 
 
 973 
 
 Copper . . 
 
 374 
 
 Zinc 
 
 304 
 
 Lead 
 
 24 
 
 Porcelain 
 
 11 
 
 Fire-clay 
 
 With Water as the Standard. 
 
 Water 
 Pine . 
 Lime . 
 Oak... 
 
 10 
 
 39 
 
 39 
 
 33 
 
 Elm .. 
 Ash.... 
 A pple . 
 Ebony 
 
 Relative Conducting Power of different Substances compared with each other. 
 
 Hares’ fur .. 
 Eider-down 
 Beavers’ fur 
 Raw silk . .. 
 
 Wool 
 
 Lamp-black 
 
 1-315 
 
 1-305 
 
 1-296 
 
 1-284 
 
 1-118 
 
 1-117 
 
 Cotton 
 
 Lint 
 
 Charcoal 
 
 Ashes (wood) 
 Sewing-silk . . 
 Air 
 
 981 
 
 898 
 
 363 
 
 180 
 
 12-2 
 
 11-4 
 
 32 
 
 31 
 
 28 
 
 oo 
 
 1-046 
 
 1-032 
 
 •937 
 
 •927 
 
 ■917 
 
 ■576 
 
 Relative Conducting Power of Fluids. 
 
 Mercury l'OOO I Proof spirit -312 
 
 Water -357 j Alcohol (pure) -232 
 
 Radiation of caloric . — When heated bodies are exposed to the air, they lose portions of their heat, 
 by projection in right lines into space, from all parts of their surface. 
 
 Bodies which radiate heat best, absorb it best. 
 
 Radiation is affected by the nature of the surface of the body ; thus, black and rough surfaces radiate 
 and absorb more heat than light and polished surfaces. 
 
 Water 
 
 Lamp-black ... 
 Writing-paper 
 
 Glass 
 
 India-ink 
 
 Bright lead ... 
 Silver 
 
 Table of the Radiating Power of different Bodies. 
 
 100 
 
 100 
 
 100 
 
 90 
 
 88 
 
 19 
 
 12 
 
 Blackened tin 
 Clean “ 
 
 Scraped “ 
 
 Ice 
 
 Mercury 
 
 Polished iron . 
 Copper 
 
 100 
 
 12 
 
 16 
 
 85 
 
 20 
 
 15 
 
 12 
 
 Reflection of caloric differs from radiation, as the caloric is in this case reflected from the surface 
 without entering the substance of the body : hence the body which radiates, and consequently absorbs 
 most caloric, reflects the least, and vice versa. 
 
 Latent caloric is that which is insensible to the touch, or incapable of being detected by the thermom- 
 eter. The quantity of heat necessary to enable ice to assume the fluid state is equal to that wliiclt 
 
12 
 
 HEAT. 
 
 would raise the temperature of the same weight of water 140° ; and an equal quantity of heat ia set 
 free from water when it assumes the solid form. 
 
 If 5^- lbs. of water, at the temperature of 32°, be placed in a vessel communicating with another one, 
 (in which water is kept constantly boiling at the temperature of 212°,) until the former reaches this 
 temperature of the latter quantity, then let it be weighed, and it will be found to weigh 6J lbs., showing 
 that 1 lb. of water has been received in the form of steam through the communication, and reconverted 
 '-■v. water by the lower temperature in the vessel. 
 
 i >v this pound of water, received in the form of steam, had, when in that form, a temperature oi 
 21~ J . It is now converted into the liquid form, and still retains the same temperature of 212°, but it 
 has caused 5-J lbs. of water to rise from the temperature of 32° to 212°, and this without losing any 
 temperature of itself. It follows, then, that in returning to the liquid state, it has parted with 5-J- times 
 the number of .degrees of temperature between 32° and 212°, which are equal 180°, and 180° X 54 = 
 990°. Now this heat was combined with the steam ; but as it was then not sensible to a thermometer, 
 it was called Latent. 
 
 It is manifest, then, that a pound of water, in passing from a liquid at 212° to steam at 212°, receives 
 as much heat as would be sufficient to raise it through 990 thermometric degrees, if that heat, instead 
 of becoming latent, had been sensible. 
 
 The sum of the sensible and latent heat of steam is always the same at any one temperature ; thus, 
 890° -f- 212° = 1202°. 
 
 If to a pound of newly fallen snow were added a pound of water at 172°, the snow would be melted, 
 and 32° will be the resulting temperature, 138° of heat becoming latent in the melted snow. 
 
 Latent Heat of various Substances. 
 
 Fluids. 
 
 Ice 140° 
 
 Sulphur 144 
 
 Lead 162 
 
 Beeswax.: 175 
 
 Zinc 493 
 
 Vapors. 
 
 Steam 990° 
 
 Vinegar 875 
 
 Ammonia 860 
 
 Alcohol 442 
 
 Ether 302 
 
 Sensible caloric is free and uncombined, passing from one substance to another, affecting the senses in 
 its passage, determining the height of the thermometer, and giving rise to all the results vfhich are 
 attributed to this active principle. See Steam. 
 
 It is frequently desirable to convert the degrees of heat, as indicated by one thermometer, into its 
 equivalent as denoted by another. The following rules will serve this purpose for the thermometers in 
 general use : — 
 
 To reduce the degrees of a Fahrenheit thermometer to those of Reaumur and of the centigrade ; the 
 i,ero of the Reaumur scale being at the freezing point, and 80° at the boiling point, whilst the zero oi 
 the centigrade is at the freezing point, and 100° at the boiling. See Thermometer. 
 
 Fahrenheit to Reaumur. — Rule. — Multiply the number of degrees above or below the freezing point 
 t>v 4, and divide by 9. 
 
 Thus, 212° — 32 = 180 X 4 = 720 9 = 80, Ans. 
 
 + 24° — 32 = 8X4= 32 -7-9 = 3’5, Ans. 
 
 or 3'5 below zero. 
 
 Fahrenheit to centigrade. — Rule. — Multiply the number of degrees above or below the freezing point 
 by 5, and divide by 9. 
 
 Thus, 212° — 32 = 180 X 5 = 900 Q- 9 = 100, Ans. 
 
 Or multiply the degrees of Fahrenheit by '444 for reducing them to Reaumur, and by '555 for reducing 
 them to centigrade. 
 
 Medium heat of the globe is placed at 50° ; at the torrid zone, 75° ; at moderate climates, 50° ; near 
 the polar regions, 36°. 
 
 The extremes of natural heat are from .70° to 120° ; of artificial heat, from 91° to 36,000°.’ 
 
 Evaporation produces cold, because caloric must be absorbed in the formation of vapor, a large 
 quantity of it passing from a sensible to a latent state, the capacity for heat of the vapor formed being 
 greater than that of the fluid from which it proceeds. 
 
 Evaporation proceeds only from the surface of the fluids, and therefore, other things equal, must depend 
 uj>on the extent of surface exposed. 
 
 When a liquid is covered by a stratum of dry air, evaporation is rapid, even when the temperature 
 is low. 
 
 Table of Effects upon Bodies by Heat. 
 
 Fahrenheit. 
 
 Cast-iron, thoroughly smelted 27 54° 
 
 Fine gold, melts 1983 
 
 Fins silver, melts 1850 
 
 Copper melts 2160 
 
 Brass, melts 1900 
 
 Red heat, visible by day 1077 
 
 Iron, red-hot in twilight 884 
 
 Common fire 790 
 
 Iron, bright-red in the dark 752 
 
 Zinc, melts 740 
 
 Quicksilver, boils 630 
 
 Linseed oil boils 600 
 
 Fahrenheit 
 
 Lead, melts 594 3 
 
 Bismuth, melts 476 
 
 Tin, melts 421 
 
 Tin and bismuth, equal parts, melt 283 
 
 Tin 3 parts, bismuth 5, and lead 2, melt... 212 
 
 Alcohol, boils 174 
 
 Ether, boils 98 
 
 Human blood (heat of) 98 
 
 Strong wines, freeze 20 
 
 Brandy, freezes 7 
 
 Mercury, melts - -89 
 
HEDDLES. 
 
 15 
 
 Wedge-wood’s zero is 10‘7'7° of Fahrenheit, and each of his degrees is equal to 130° of Fahrenheit. 
 
 Expansion of Solids. 
 
 At 212°, the length of the bar at 32° considered as 1-0000000. 
 
 -001495€ 
 
 -0017450 
 
 -0019062 
 
 -0020100 
 
 -0004928 
 
 -0028436 
 
 -0029420 
 
 To find the expansion in surface or in volume, it must be remembered that each dimension of a solid 
 experiences a similar proportional expansion. 
 
 Glass 
 
 Platina 
 
 -0009542 
 
 -0011112 
 
 Gold 
 
 Copper.. 
 
 
 -0011899 
 
 Silver 
 
 Marble 
 
 -0011041 
 
 Fire oriek 
 
 Forged iron 
 
 -0O12575 
 
 Lea 1 .... 
 
 Granite 
 
 
 Zim 
 
 Table of the Expansion of Air by Heat. — By Mr. Dalton. 
 
 Fahrenheit. 
 
 Fahrenheit. 
 
 Fahrenheit. 
 
 32° 1000 
 
 33 1002 
 
 34 1004 
 
 85 1107 
 
 40 1021 
 
 45 1032 
 
 50° 1043 
 
 55 1055 
 
 60 1066 
 
 65 1077 
 
 TO 1089 
 
 75 1099 
 
 80° 1110 
 
 85 1121 
 
 90 1132 
 
 100 1152 
 
 200 1354 
 
 212 1376 
 
 Melting Point of Alloys. 
 
 Lead 2 parts, tin 3 parts, bismuth 5 parts, melts at 212° 
 
 “ 1 “ “4 “ “ 5 “ melts at 246 
 
 “ 1 “ “1 “ melts at 286 
 
 “ 2 “ “1 “ melts at 336 
 
 “ 2 “ “ 3 “ melts at 334 
 
 “ 8 “ “1 “ melts at 392 
 
 “ 2 “ “1 “ common solder, melts at 475 
 
 “ 1 “ “2 “ soft solder, melts at 360 
 
 Boiling points. — The boiling point of water, from 27 to 31 inches of the mercurial column, varies 
 1-65° for every inch, being at 30 inches 212° ; and on this variation is founded the apparatus for deter- 
 mining altitudes. 
 
 , Comparative Heat from various Fuels. 
 
 3 lb. of tolerably good coal will raise the temperature of 60 lbs. of water from 32° to 212°. 
 
 1 lb. of kiln or perfectly dried wood will effect the same on 35 lbs. 
 
 1 lb. of wood simply dried in the air “ “ 26 lbs. 
 
 1 lb. charcoal “ “ 79 lbs. 
 
 Turf of good quality yields as much heat for equal weights as wood, and the heat it gives out by 
 radiation whilst burning has been considered even greater than that of wood. 
 
 For the various methods of applying heat to the warming of buildings, see article Warming. 
 
 HEDDLES, Machine for making Weavers'. This machine is the invention of Mr. Kassimir Yogel, 
 of Lowell, Massachusetts. 
 
 The object of the machine is to make weavers’ heddles from the thread, casting the loop by braiding 
 instead of knotting, and performing triple the amount of work, and better than can be done by hand. 
 A patent is also secured for the peculiar eye of the heddle, so that both machine and its results are 
 protected. 
 
 Description. — Fig. 2251 is a perspective view, and shows gangs of different heddles winding on the 
 Deams. A A is the iron framing. B are the driving and slack pulleys. C is the lever to geer and un- 
 geer. E E are the bobbins, with the thread to make the heddles. There is a small shaft under the bed 
 of E, which, by small cog-wheels on the same, operate and revolve the bobbins by geering into F. 1 1 
 are the heddles after the eye is formed, winding up on the beams L L. The gang of wheels at the left 
 are for the purpose of connecting the shafts of the beams to be driven by the main shaft below. The 
 number of eyes to the foot in the heddles can be increased or diminished by the geering of these small 
 wheels. K is a small bearing for the shaft of L, and J is the shaft with a screw cut on part of it. This 
 is for winding the heddle gradually along the beam, and as K is a grooved and wormed faced pulley- 
 driven slowly by the small gang of wheels at the right, the shaft J is wormed slowly through its bear- 
 ings, carrying the beam to let the heddles wind one after another on the same. The heddles are formed 
 of a double cord, which is twisted by the bobbins revolving, and the eyes or loops are formed by the 
 bobbins being interlocked, braiding the two strands at the two points which form the eye of the heddles. 
 The section views will explain the operations better in detail. 
 
 As the same letters indicate like parts on all the following engravings, we shall describe them col 
 lectively. Fig. 2252 is a side elevation. Fig. 2253 is a top view of the revolving tables and spindles. 
 Fig. 2254 is an end elevation. Fig. 2255 is a view of the under side of the machine, showing the geer- 
 ing by which the tables that carry the spindles are made to revolve. 
 
14 
 
 HEDDLES. 
 
 A is the heddle-beam. B B BB are revolving spool-frames or tables. C represents the spool-spin- 
 dles. a are slots in the spool-tables. Each table has six slots or spindle recesses, but only three are 
 occupied at once with the spindles. As the tables revolve, three slots are occupied with spindles and 
 three are empty alternately, and an occupied slot in one is brought opposite to an empty recess in ita 
 
 2251. 
 
 fellow-table, as seen in Fig. 2253. The tables BB constitute one pair, and the tables B 2, B 3, another, 
 forming two distinct harness, one on each side on two beams, but driven by the same geering. The 
 yarn is put on the spindles 0, and passes through a hole in the top of the flyers D, or over a depression, 
 tig. 2252, to hold it in its place, and then passes under c, a recurved wire, that has a perforated weight 
 
 j a at each end. The flyers pass through these holes, and the legs serve as guides to the weights. 
 Phis is to take up the slack of the yarn. The spindles have each a groove in their lower parts, adapted 
 to slide into the recesses of the tables when the recesses coincide. The platform E E has circular 
 avities for the lower ends of the spindles. F F, Fig. 2252, are fast and loose pulleys to drive the 
 
HEDDLES. 
 
 1 
 
 shaft G. A bevel-wheel H, on G, gives motion to the revolving spool-tables by toothed wheels, as seen 
 at Fig. 2255. The bevel-wheel I, Fig. 2252, gives motion to the heddle-beams by geering into J, on 
 the shaft K. This shaft carries a worm-wheel, which geers into M to drive A. N is an eccentric on K 
 
 to vibrate g, a shipper, which shifts the spindles from one table to another; the opposite ends of g 
 eperate on two pairs of tables. A connecting-rod with N vibrates the shippers. N is connected with K, 
 and turn9 with it by clutch-pins, and when these are not engaged the shafts turn without 1ST. i i, Fig. 
 2254, is a pin that passes through If, projecting out above and below, nearly in contact with K. There 
 
 are two clutch pins on K, either of which may be brought in contact with i, as the eccentric- wheel is 
 made to slide up and down on the shaft. O, Figs. 2252 and 2254, is a forked lever with its fulcrum at e 
 Its fork ends m m embrace 1ST, the eccentric, and raise and lower it at proper times, n n is a spiral 
 spring attached to the forked lever, serving to draw it inwards to depress the eccentric and make it 
 
HELIOTROPE. 
 
 16 
 
 clutch with the lever clutch-pin. On the wheel M are cams or lifting pieces jj p, which, when they 
 come in contact with the end of 0, force it out and raise hi, the eccentric, so as to en ,r a <r e with the 
 upper clutch-pin at the required time, as will be understood by Fig. 2254. The axis of A°is°P, a screw 
 Tig. 2252, tapped into the frame of the machine and moves A endwise as it revolves, to wind th* 
 heddles, as they are made spirally on the beams, q is the smooth axis of A, on which the beam slides, 
 moved by the screw on the guide-rods rr. Q Q are rods that may be inserted in grooves in A. The 
 semi-diameter of A must be of the length of the heddles. After the number of heddles for a harness 
 have been made, grooved pieces may be slipped over Q and glued upon them to embrace the twisted 
 strands, or any other mode may be adopted. The shipper connecting-rod h, (which looks like an «,) 
 Figs. 2252 and 2253, has a hinge-joint t, to allow it to be lifted from the shipper g. The small bevel- 
 wheel J, on the shaft K, is one-third of the diameter of the driving-wheels, when there are three spindles 
 on the table, and therefore makes the changes of the spindles in the recesses in one revolution of the 
 revolving spool-tables. If there were four spindles in the table, the wheel J would be one-fourth the 
 diameter of the driving-wheel, drc. 
 
 To explain its operation, Fig. 2251 exhibits a different arrangement of mechanical parts from the sec- 
 tion views, but they are just the mechanical equivalents to accomplish the same thing. Heddle or 
 harness making is the formation -of eyes by two cords being knotted together. These eyes must be 
 formed at regular distances on the harness. This machine forms two cords by B B, revolving and twist- 
 ing the yarn on the three spindles, one by each table revolving, the cord winding at the same time as it 
 is twisted on the beam A. Row to form four eyes on the heddles every revolution of the beam, 
 look at Fig. 2253. If the strands that make the two cords were interlocked at certain periods, eight 
 times during the revolution of A, that four eyes would be formed by the strands of the two cords being 
 thus at certain points braided into one another. This is the way this machine does its work, and this 
 can be done by the forked lever in Fig. 2254 shifting the shipper, or by cams on the inside of the upper 
 geer-wheel of Fig. 2251. To make the spindles in c interlock to braid the eyes. The cams or clutch 
 operate the shipper g, so that instead of vibrating from side to side, as now seen in Fig. 2253, touching 
 the spindles outside, it is (the shipper) stopped by the resting of the eccentric one-sixth of the revolu- 
 tion of the tables, and then it will be easily perceived that the shipper will take into the inside of the 
 spindle e and throw it into the empty recess a of the other table, which coincides, thus interlocking the 
 threads and braiding the two cords together into one, forming an eye of the heddle by braiding instead 
 of knotting. It will be observed, too, that the clutch can be changed by cams, to operate the shipper, 
 to make as large or as many eyes in a foot as may be desired ; but the changing or passing of the 
 spindles from one table to another must be performed by the shipper twice for one eye, according to 
 the length of the eye, and they are not shifted again until A has revolved the distance wanted to form 
 the base of a new eye for the harness. 
 
 HELIOTROPE Reflecting Lantern, used by Major J. D. Graham as meridian marks for great distances, 
 in 1841, while tracing the due north line from the monument at the source of the river St. Croix. 
 
 The lantern was constructed by Messrs. Hemy N. Hooper & Co. of Boston, under Maj. G.’s directions. 
 It was similar in form to the Parabolic Reflector Lantern, sometimes used in light-houses, but much 
 smaller, so as to be portable. 
 
 The burner was of the argand character, with a cylindrical wick, whose transverse section was half 
 an inch in diameter, supplied with oil in the ordinary manner. This was placed in the focus of a para- 
 bolic reflector, or paraboloid, of sheet-copper, lined inside with silver about l-20th of an inch in thick- 
 ness, polished very smooth and bright. The dimensions were as follows : 
 
 Inches, 
 
 Diameter of the base of frustrum of reflector 16- 
 
 Distance of vertex from base S'15 
 
 Distance of focus from vertex 2’25 
 
 Diameter of cylindrical burner '60 
 
 Diameter of a larger burner which was never used, but which, by an adapting piece, 
 
 could be easily substituted 1 26 
 
HELIX. 
 
 17 
 
 The instrument answered the purpose for which it was intended admirably well, and was of great 
 use in tracing the due north line. While it occupied the station at Park’s Hill, 15 feet above the sur- 
 face of the ground, or 828 feet above the sea, in the latter part of September and early part of October, 
 1841, the light from it was distinctly seen with the naked eye at night, when the weather was clear 
 from Blue Hill, whose summit, where crossed by the meridian line, is 1071 feet above the sea, the 
 intervening country averaging about 500 feet above the sea, and the stations being 36 miles apart. The 
 light appeared to the naked eye, at that distance, as bright, and of about the same magnitude, as the 
 planet Venus. 
 
 The wick employed by Major G. was considerably smaller than that usually made, even for parlor 
 lamps ; and to this cause is attributed, in a great measure, the perfection with which the parallel rays 
 were transmitted from the reflecting parabolic surface, so as to make them visible at so great a distance. 
 Though a greater quantity of light is generated by a larger wick, the portion of rays reflected in a 
 direction parallel to the axis, and which alone come to the eye, is the smaller as the flame transcends 
 the focal limit. The size of wick most advantageous for use may easily be determined by experiment. 
 The smaller is its transvere section, provided it is only large enough to escape being choked up by 
 the charred particles, even one-third, or perhaps less, the further the light would he visible. 
 
 The heliotrope, which is employed in the day time, was made by order of Mr. Hassler, at the instru- 
 ment shop of the coast survey office. It was a rectangular parallelogram of good German plate-glass, 
 1 4-5ths by 1 l-5th inch in size, giving an area of reflecting surface of 2 square inches. This also 
 was seen at the distance of 30 miles. 
 
 HELIX. A spiral curve. The cy- 
 lindrical or screw helix is the curve 
 described upon the surface of a cy- 
 linder by a point revolving round it, 
 and at the same time moving par- 
 allel to its axis by a certain invaria- 
 ble distance during each revolution. 
 
 Figs. 2256 and 2257, to con- 
 struct the helical curve described 
 by the point A upon a cylinder pro- 
 jected horizontally in the circle A' 
 
 C' F', the pitch being represented 
 by the line A' A 3 . Divide the pitch 
 A' A 3 into any number of equal 
 parts, say eight ; and through each 
 point of division, 1, 2, 3, &c., draw 
 straight lines parallel to the ground 
 line. Then divide the circumfe- 
 rence A' C' F' into the same num- 
 ber of parts ; the points of division 
 B', C', E', F', &c., will be the hor- 
 izontal projections of the different 
 positions of the given point during 
 its motion round the cylinder. 
 
 Thus, when the point is at B' in 
 the plan, its vertical projection will 
 be the point of intersection B of the 
 perpendicular drawn through B’ 
 and the horizontal drawn through 
 the first point of division. Also 
 when the point arrives at C' in the 
 plan, its vertical projection is the 
 point C, where the perpendicular 
 drawn from C' cuts the horizontal 
 passing through the second point of 
 division, and so on for all the re- 
 maining points. The curve ABC 
 F A 3 drawn through all the points 
 thus obtained, is the helix required. 
 
 A helical surface is generated by 
 the revolution of a straight line 
 round the axis of a cylinder; its 
 outer end moving in a helix, and 
 the fine itself forming with the axis 
 a constant and invariable angle. 
 
 The conical helix differs from the cylindrical one in that it is described on the surface of a cone in- 
 stead of on that of a cylinder ; but the construction differs hut slightly from the one described. By 
 following out the same principles, helices may be represented as lying upon spheres or any other surfaces 
 of revolution. In the arts are to he found numerous practical applications of the helical curve, as wood 
 and machine screws, geers and staircases. 
 
 HEPTAGON. A figure having seven equal angles and sides. 
 
 Vol. II.— 2 
 
18 
 
 HORN. 
 
 H F. X A ED RON, the Cube. One of the five regular or Platonic bodies, and so called from its having 
 six faces. The square of the side or edge of a hexaedron is one-third of the square of the diameter of 
 the circumscribing sphere ; and hence the diameter of a sphere is to the side of its inscribed hexaedron 
 as V 3 to 1 . 
 
 HEXAGON. A figure of six sides and angles. Angle at the centre = 60° ; angle at the circum- 
 ference = 120° ; area to side, 1 = 2-5980762 ; area to any side, (S) = 3 2 x 2-5980762. 
 
 HIGH-PRESSURE ENGINE. The simplest form of the steam engine is the non-condensing, or 
 high-pressure engine. In this engine the condensing apparatus is dispensed with, and steam being ad- 
 mitted into the cylinder, at a high temperature, and consequently high pressure, and having acted on 
 the piston, is allowed to escape into the open air. A part of the force of the steam is of course ex- 
 pended in overcoming the pressure of the atmosphere, and it is only that portion of the steam’s elastic 
 force that exceeds 15 pounds to the square inch that is effective in moving the engine. The surplus pres- 
 sure is usually from 30 to 40 pounds on the circular inch. See Stationary Engines, and Engines 
 Varieties of. 
 
 HINGE, Taft’s double-jointed hinge and door-spring. Figs. 2260 and 2261. This hinge is so constructed 
 that it admits of the opening of the door, or gate, in either direction, and in combination with it is a spring 
 connected by a chain with the casing, whereby the door is held close to it as well as made to close 
 itself. Each hinge employed in this improvement may consist of four or more pieces, two of which are 
 
 side plates with knuckles attached thereto. The connecting plates with their knuckles are connected 
 by pivots to those of the plates, and each connects the plate to the other, so that when the hinge is 
 opened in the opposite direction the connecting plate changes sides and folds upon the plate, so that the 
 hinge presents the same appearance in either position. 
 
 HINGES. The joints on which doors, gates, &c., turn. 
 
 HIP. The external angle formed by the meeting of the sloping sides of roofs which have their 'wall- 
 plates running in different directions. 
 
 HORN. See Animal Matter used in the Arts. 
 
 HORN, machine for pressing. Horn, tortoise-shell, and many other animal substances, are capable 
 of being softened by heat and moulded by pressure into any shape and with any design in the sharpest 
 
 *nd most delicate relief. A screw press has usually been employed for this purpose, but the one rep- 
 res .nted bv Fig. 2262, which is a section through its centre, is far superior. 
 
HORSE. 
 
 10 
 
 A A is a box of cast-iron. B is a copper to contain the hot water, and M is a grata for the fire to heat 
 the same. 0 is the smoke-pipe. F F G- is the press, made of strong cast-iron, and capable of being 
 drawn up and let down in the water at pleasure, by means of racks D D, at each side, actuated by 
 pinions J J. The axles of these pinions cross the machine and have each a wheel at the end, moved by 
 two arms, or screws cut upon the axis and turned by the handle H. The press is guided in the ascent or 
 descent by grooves in the side of the boiler. When raised up out of the water, the moulds, with the horn 
 or tortoise-shell between them, are put beneath the presser, and a severe pressure is produced by turn- 
 ing the wheel K. This wheel has an endless screw R upon its axis, which works the teeth of a large 
 wheel L, fixed on the top of the screw P. The screw is received into an interior screw formed within 
 the box or presser I, which is guided and prevented turning round by the cross-bar E, through which 
 the presser is fitted; by this means, when the screw P is turned round by the wheel L and endless 
 screw, the horn or tortoise-shell is pressed between the moulds ; the press is then lowered again into 
 the water of the boiler, in order to be still further softened by the boiling ; but when the press is down 
 in the boiler, the screw can be screwed tighter by turning the wheel K until the desired impression is 
 obtained. By turning the handle H, the press is then raised up out of the boiler, and by turning back 
 tire wheel K the pressure is released and the moulds can be removed. 
 
 HORSE. The power of a horse when applied to- draw loads, as well as when made the standard of 
 comparison for determining the value of other powers, has been variously stated. 
 
 The relative strength of men and horses depends, of course, upon the manner in which their strength 
 is applied. Thus, the worst way of applying the strength of a horse is to make him carry a weight up 
 a steep hill, while the organization of the man fits him very well for that kind of labor. And three 
 men, climbing up a steep hill, with each 100 lbs. on his shoulders, will proceed faster than most horses 
 with 300 lbs. 
 
 It is highly useful to load the back of a drawing horse to a certain extent ; though this, on a slight 
 consideration, might be thought to augment unnecessarily the fatigue of the animal: but it must 
 be recollected that the mass with which the horse is charged vertically is added in part to the effort 
 Which he makes in the direction of traction, and thus dispenses with the necessity of his inclining so 
 much forward as he must otherwise do : and may, therefore, under this point of view, relieve the 
 draught more than to compensate for the additional fatigue occasioned by the vertical pressure. Carmen, 
 and wagoners in general, are well aware of this, and are commonly very careful to dispose of the load in 
 such a manner that the shafts shall throw a due proportion of the weight on the back of the shaft horse. 
 
 The best disposition of the traces during the time a horse is drawing is to be perpendicular to the 
 position of the collar upon his breast and shoulders : when the horse stands at ease, this position of the 
 traces is rather inclined upwards from the direction of the road ; but when he leans forward to draw 
 the load, the traces should then become nearly parallel to the plane over which the carriage is to be 
 drawn ; or, if he be employed in drawing a sledge, or any thing without wheels, the. inclination of the 
 traces to the road should be about 18£°, when the friction is one-third of the pressure. 
 
 When a horse is made to move in a circular path, as is often practised in mills and other machines 
 moved by horses, it will be necessary to give the circles which the animal has to walk round the 
 greatest diameter that will comport with the local and other conditions to which the motion must be 
 subjected. It is obvious, indeed, that, since a rectilinear motion is the most easy for the horse, the less 
 the line in which he moves is curved, with the greater facility he will walk over it, and the less he need 
 recline from a vertical position : and besides this, with equal velocity the centrifugal force will be less 
 in the greatest circle, which will proportionally diminish the friction of the cylindrical part of the trun- 
 nions, and the labor of moving the machine. And, further, the greater the diameter of the horse-walk, 
 the nearer the chord of the circle in which the horse draws is to coincidence with the tangent, which is 
 the most advantageous position of the line of traction. On these accounts it is that, although a horse 
 may draw in a circular walk of 18 feet diameter, yet in general it is advisable that the diameter of such 
 a walk should not be less than 25 or 30 feet ; and in many instances 40 feet would be preferable to either. 
 
 It has been stated by Desaguliers and some others, that a horse employed daily in drawing nearly 
 horizontally can move, during eight hours in the day, about 200 lbs. at the rate of 2£ miles per hour, or 
 3f feet per second. If the weight be augmented to about 240 or 250 lbs., the horse cannot work more 
 than six hours a day, and that with a less velocity. And, in both cases, if he carry some weight, he 
 will draw better than if he carried none. M. Sauveur estimates the mean effort of a horse at 175 
 French, or 189 avoird. pounds, with a velocity of rather more than three feet per second. But all these 
 are probably too high to be continued for eight hours, day after day. In another place Desaguliers 
 states the mean work of a horse as equivalent to the raising a hogshead full of water (or 550 lbs.) 50 
 feet high in a minute. But Mr. Smeaton, to whose authority much is due, asserts, from a number of 
 experiments, that the greatest effect is the raising 550 lbs. forty feet high in a minute. And, from 
 some experiments made by the Society for the Encouragement of Arts, it was concluded, that a horse 
 moving at the rate of three miles an hour can exert a force of 80 lbs. The proper estimate would be 
 that which measures the weight that a horse would draw up out of a well ; the animal acting by a hor- 
 izontal line of traction turned into the vertical direction by a simple pulley, or roller, whose friction 
 ehould be reduced as much as possible. 
 
 Tredgold has directed his attention to the subject of “ horse-power .” His expression for (he 
 
 power of a horse is 250 v 
 
 and 
 
 250 dv 
 
 (-0 
 
 1 -j- n 
 
 for the day's work in lbs. raised oue 
 
 mile; d being the hours which the horse works in a day, and the weight of the carriage to that of the 
 
 load as n . 1 
 
 „ , ■ 14‘7 
 
 He also gives —f~r, 
 
 V “ 
 
 for the greatest speed in miles per hour, when the horse is unloaded. 
 
20 
 
 HORSE-POWER. 
 
 He gives the following table of the comparison of duration of a horse’s daily labor and maximuir 
 velocity unloaded : — 
 
 Duration of labor. Maximum velocity unloaded 
 
 Hours. in miles per hour. 
 
 1 14*7 
 
 2 10-4 
 
 Duration of labor. Maximum velocity unloaded 
 
 Hours. in miles per hour. 
 
 6 G* 
 
 3 8 5 
 
 8 5-2 
 
 4 73 
 
 5 6-6 
 
 9 4-9 
 
 10 40 
 
 Taking the hours of labor at 6 per diem, the utmost he would recommend, the maximum of useful 
 effect he assigns at 125 lbs., moving at the rate of three miles per hour; and regarding the expense of 
 carriage in that case as unity, then, 
 
 Miles per 
 
 Proportional 
 
 Moving force 
 
 hour. 
 
 expense. 
 
 or traction. 
 
 o 
 
 1-125 
 
 166 lbs. 
 
 3 
 
 1* 
 
 125 “ 
 
 34 
 
 1 0285 
 
 104 “ 
 
 4 
 
 1-125 
 
 83 
 
 44 
 
 1-333 
 
 024 “ 
 
 5 ” 
 
 1-8 
 
 41 * “ 
 
 
 
 9. 
 
 364 “ 
 
 That is, the expense of carrying goods at 3 miles per hour being 1, the expense at 4-J miles per hour 
 will be 1 ; the expense being doubled when the speed is 5J miles per hour. 
 
 Various estimates have been made of a horse’s power by Desaguliers, Smeaton, and others ; but the 
 estimate now generally adopted as a standard for measuring the power of steam-engines, is that of Mr. 
 Watt, whose computation is about the average of those given by the other writers. The measure of a 
 horse’s power, according to Mr. Watt, is, that he can raise a weight of 33,000 pounds to the height of 
 one foot in a minute. 
 
 Horse-power , as the measure of the force of steam-engines. — It is by this nominal power that engines 
 are usually bought and sold and always spoken of, unless when the contrary is expressly stated. 
 
 The following is Boulton and Watt’s rule for determining the nominal horses’ power. 
 
 Let D = the diameter of the cylinder in inches. 
 
 V = half the velocity of the piston in feet per minute. 
 
 Then 
 
 (D" — 4 D) V 
 2650 
 
 the number of nominal horses’ power. 
 
 But in order to determine V before the engine has been made, Boulton and Watt fixed upon an em- 
 pirical velocity for each different length of stroke. The several velocities are as follow : 
 
 Stroke, 
 ft. in. 
 2 0 
 2 6 
 3 0 
 
 3 6 
 
 Velocity. 
 
 ft. 
 
 160 
 
 170 
 
 180 
 
 190 
 
 Stroke, 
 ft. in. 
 4 0 
 
 4 6 
 
 5 0 
 
 Velocity. 
 
 ft. 
 
 200 
 
 210 
 
 220 
 
 And so on, with 10 feet of additional velocity for every 6 inches of additional stroke. The original 
 engines of the Thames and Shannon, constructed by Boulton and Watt, were rated at 80 horse-power, 
 the cylinders being 411 inches in diameter, and the length of stroke 4 feet 6 inches, (47’5) 2 — 4 (47'5) =: 
 2066-25 X 105 = 217930 2650 = 83 horse-power nearly, instead of 80. Land engines of 43J inches 
 
 diameter of cylinder and 8 feet stroke, making 16 double strokes in a minute, were rated by Boulton 
 and Watt at 80 horse-power. The average effective pressure on the piston is rated at barely 7 lbs. per 
 square inch, and the power may be thus computed, (43-R 2 X '7854 = 1486'2 X by 7 and 266, and — by 
 33,000 = about 80 horse-power. In marine engines a greater area of piston is allowed to represent a 
 horse-power than in land engines, because the motion of the piston is supposed to be slower, but the 
 effective force is calculated a little higher, or at 7’3 per square inch. 
 
 HORSE-POWER, Bogardus’s. This improvement in the horse-power for driving machinery is based 
 on the principle of the well-known sun and planet motion, and consists of a base-frame having cogs in 
 the inner periphery of the rim into which mash the cogs of a pinion on the lower end of the arbor of the 
 planet-wheel, the cogs of which drive a pinion on a central shaft that carries the driving-pulley, the arbor 
 of the planet-wheel being adapted to turn in a sleeve, in a travelling wing to which the horse-beam is 
 secured ; and the said wing having another and parallel sleeve that turns on a central hollow standard 
 of the frame through which the shaft of the central pinion arid driving-pulley passes, and in which 
 it turns. 
 
 The base-frame is cast in one piece, consisting of the central hub. and the outer ring connected by 
 radial arms, and standing on legs. The central hub is cast with a hollow standard properly turned with 
 a slight taper, to which is fitted a sleeve that turns thereon freely but accurately, and resting on the 
 upper surface of the hub ; and likewise with this sleeve, and making part thereof, is cast a wing, to 
 which is secured by bolts the liorse-beam or lever, by which the whole is operated. The other end ot 
 the wing is also provided with another sleeve cast therewith, and parallel to the other, to which is fitted 
 accurately (but yet to admit of turning freely) the arbor of the planet-wheel and planet-wheel pinion, 
 the former being at the top and the latter at the bottom. One of these, either the wheel or the pinion, 
 can be permanently attached to the arbor, and the other keyed on after it has been inserted in the 
 
HORSE-POWER. 
 
 21 
 
 sleeve. The cogs of the pinion of the planet-wheel take into the cogs formed in the inner periphery ol 
 the rim of the base-frame, and which may be called the master-wheel ; and the cogs of the planet-wheel 
 take into the cogs of and drive the central pinion on the upper end of a vertical shaft that passes through 
 and turns freely but accurately in the central hollow standard, which is adapted to it, the driving-pulley 
 being keyed on the lower end and below the hub. 
 
 A band from the driving-pulley can be carried under the frame and between the legs, to any. place 
 required in the usual manner to drive any piece of machinery ; but if desired, the driving-pulley can be 
 attached to the central shaft above the central pinion, Fig. 2264. The arbor of the planet-wheel is 
 oiled through a hole in the wheel which delivers it at the junction of the sleeve and arbor; and in like 
 manner the central shaft and the sleeve that turns on the central standard are oiled by pouring the oil 
 through a hole in the central pinion, which delivers it on the upper end of the hollow standard, and 
 which is grooved to direct the oil to its inner and outer periphery. 
 
 The whole apparatus is made light and portable, rests on the case-frame, and turns on the central 
 standard, which makes part of the base-frame, without supports or bearings at the top. The whole can 
 be taken apart for transportation, and can be again put together with ease. The whole strain comes 
 on and is supported by the hollow standard, which being cast with the base-frame will resist any strain 
 that can be applied to it by the horses employed to drive the machine. The sleeves of the wing and 
 the inside of the central standard are or may be laid with soft metal. 
 
 Arranged to carry a shaft under the foot-path, or an upright shaft to the floor above. 
 
 In some ferry-boats and machines, horses are placed on a revolving platform, which passes backward 
 under the feet whenever the horse exerts his strength in drawing against a fixed resistance, so that the 
 horse propels the machinery without moving from his place. A horse may act within still narrower 
 limits, if he is made to stand on the circumference of a large vertical wheel, or upon a bridge supported 
 
HOrtSE-SHOE MACHINE. 
 
 22 
 
 by endless chains which pass round two drums, and are otherwise supported by friction-wheels. Va- 
 rious other methods have been practised for applying the force of animals, but most of them are attended 
 with great loss of power, either from friction, or from the unfavorable position of the animal. 
 
 For agricultural purposes, the movable-platform horse-power is probably the best, and is coming very 
 much into use. It consists of an inclined platform, or endless chain, provided with slats of wood upon 
 which the horse treads, giving motion to a horizontal shaft by means of teeth in the chain or rack, work 
 mg into a pinion on the shaft. It has very lately been patented in Italy under the name of impulsoria, 
 and is in experimental use on the Southwestern Railway in England, and is thus described in a late 
 number of the London News : — 
 
 The patent impulsoria, for railways, consists in introducing the animals into a kind of coach, called 
 impulsoria, by which they transmit their acting power to the leading -wheels. This transmission is 
 conveyed by a very simple means, rendering useful both the driving power of the animals and their own 
 weight. The horse being thus introduced into the impulsoria, is placed upon a perfect rectilinear, arti- 
 ficial ground, or platform, turning so easily that the animal, which is yoked to the shafts, when it walks, 
 does not itself advance, but, what amounts to the same thing, the platform itself is pushed backward, 
 as shown in Fig. 2266. By this artificial ground platform, called by the patentee pcdivella, is moved an 
 axle, armed with a pulley, from which, by means of a rope, the motion is conveyed to the axletree oi 
 the leading wheels. The varying proportions between the diameters of the pulleys give different de- 
 grees of speed. The horses are to be worked always at their usual pace, whilst the new locomotive 
 will be able to run at any requisite speed, without ever altering the usual walking pace of the horses, 
 which are inside the impulsoria, as on the floor of a room, sheltered from the weather. 
 
 The importance of introducing the horses into the carriage in order to get more speed from the sur- 
 plus of the acting power, had been long thought of, and the principle has been several times attempted 
 in England, France, and Italy, but hitherto without success. 
 
 The new machine (whose inventor is Signor Clemente Masserano, from Pignerol, Piedmont) haa 
 been brought from Italy to England, and deposited at the Nine-elms terminus of the Southwestern 
 Railway, where it may be seen working on the line. It has been made for two horses only, and they 
 work it very well on the pedivella. More than thirty wagons have been already experimentally drawn 
 by it up the very inclined line of the station. For working it up and down the station, a wagon is fast- 
 ened to it when it attains a speed of seven miles an hour. In the experiment to be made on the great 
 line, it is expected to gain a speed of from fifteen to twenty miles an hour. The impulsoria runs either 
 way, like the steam-engine ; but the driving horses do not change direction or movement. They can 
 instantly be stopped, without stopping the machine ; and the machine can likewise be stopped while 
 the horses continue to walk on th e pedivella, without transmitting motion to the leading wheels. 
 
 By the simple manner in which the horses exercise their moving power on the new machine, they 
 can work easily the usual time, commonly about eight hours a day. 
 
 Such economy is of the utmost importance to the numerous interests engaged in the railways subject 
 to enormous working expenses. The principal advantage of the new machine will be to afford very 
 cheap locomotion on all branch lines, thus extending the advantage of the railway to localities hitherto 
 impracticable from the expensive moving power. 
 
 The directors of the Southwestern Railway were the first to receive the impulsoria on their line 
 where they have granted every facility to its ingenious inventor. 
 
 HORSE-SHOE, Burden’s Patent Machine for making. From the specifications of the patents we 
 extract the following description of the machine and its operation. 
 
 Fig. 2207, section and plan of the machine for rolling, drawing, and shaping horse-shoes; aaaa sta- 
 tionary or outside frame ; bhhh feet which support the same ; c the fly-wheel ; d the connecting-rod 
 e e the crank ; ff the moving-frame ; g the rack, having cogs in it, which is bolted into the moving-frame, 
 and which mashes or fits into the segment A, having long cogs, as seen at h, the lower or under segment 
 which is fastened into the roller i, as seen at i. Fig. 2269, K the moving-jaw ; / 1 the side steels or iron, 
 between which the piece of iron is confined and the sides, while it is drawn or rolled by the swedges D D 
 having steels or swedges E E the exact thickness of the shoe intended. 
 
 It will be observed that one of these side steels or irons is fastened into the moving-jaw k or K, by 
 means of screw-bolts, while the other is similarly fastened into the moving-frame f f. m a button, or cam, 
 which, when the moving-frame ff is moved or drawn backwards and forwards by the crank e , through 
 the connecting-rod d, it strikes against the pin or stop n, which permits the button or cam o to push back 
 or open the moving-jaw k, when it strikes against the pin or stop p on the other side of the stationary 
 frame, by which means the piece of iron which may be between the side steels or irons, and which is 
 
HORSE-SHOE MACHINE. 
 
 23 
 
 drawn or rolled to the shape desired, is permitted to drop out. q, a pin or stop, which, when the earn 
 o strikes against it on the moving-frame’s return motion, permits the cam in, when it strikes against tho 
 pin or stop r, to close the moving-jaw k. It will be observed that when the moving- frame// has per- 
 formed its forward motion, then the cam in strikes against the stop n, which permits the cam o to open 
 the moving-jaw k by striking against the stop p, which allows the piece of iron, which may have been 
 rolled or shaped to a horse-shoe, to drop from between the side steels or irons ll. s, a chisel fastened 
 '■y screw-bolts on the top of the side steel or iron l\ t, a chisel fastened by screw-bolts in the chise’ 
 box u u u. 
 
 It will be observed that the box uuu turns on a pin in the moving-frame, which, when the crank 
 pushes back the moving-frame, the head or box part strikes against the pin or piece of iron w, and 
 presses up the chisel t against the chisel .s, and cuts off the piece of iron to the length intended for a 
 horse-shoe, v , a piece of iron intended to draw back the chisel-box uuu, as seen at Fig. 2268 ; xxxx, 
 brasses on which the moving-frame slides backwards and forwards ; y , a piece of iron to lay the bar on 
 as a guide while in the act of feeding into the machine. Z Z end view and section of the posts through 
 which the rollers i i are fastened and revolve ; A, piece of iron or stop which graduates the length o, 
 shoe ; B, piece of iron having a hole in it, through which the iron or stop A passes, which graduates the 
 length of shoe ; C, the piece of iron which prevents the shoe from being drawn back by the chisel or 
 the side steel l, previous to the swedges pressing it between them. 
 
 Fig. 2268, section and elevation of machine. A, segments which are fastened into the rollers ii\ O, 
 the rack which mashes or works into the upper segment h, the cogs of which being twice the length i i 
 the under segment h permits the rack to operate into it, which, when pushed backwards and forwards 
 by the moving-frame / / the whole is put in motion, i i, the rollers into which the segments, witli 
 cogs h h and swedges I) D, with pieces or swedges EE, are fastened, k the moving-jaw; 1 1 the side 
 steels or irons between which the piece of iron is held, while it is rolled or drawn by the vertical 
 swedges D D and the steels or swedges E E to the desired shape of shoe. It will be perceived that 
 the rollers i i revolve on gudgeons. Z Z, posts or stationary frame, into which the rollers i i are fastened 
 and revolve. 
 
 Fig. 2271, sectional elevation of part of the machine, i i, the rollers in which the swedges with the 
 pieces of steel or swedges E E are fastened. 1 1, one of the side steels or irons. Id represents a piece of 
 iron as being formed into a horse-shoe. It will readily be perceived that by grinding the steels or swedges 
 E E, any shape or taper required can be given to the piece of iron or shoe marked H. It will be ob- 
 served that the four views or figures, as above described, represents the part or parts of machinery for 
 cutting ofti rolling, or drawing the iron into the shape required for horse-shoes, and that Fig. 2267* is a 
 
24 
 
 HORSE-SHOE MACHINE. 
 
 section, having the upper roller i removed for the purpose of showing more distinctly the interim 
 arrangements of the machine. 
 
 Fig. 2270, sectional elevation of part of the machine, ii the rollers. DD the swedges: the under 
 one, which is cast-iron, or may be fitted with steel swedge similar to those used for rolling or shaping 
 the shoe, as seen at D D, E E, the edge of which being similar to the flat side of a horse-shoe. The 
 upper one is also of cast-iron, so constructed as to fasten in two pieces of steel under the covers or 
 caps i i. These pieces of steel are so shaped at their edges as to groove and punch the holes at one 
 operation. They are graduated as to depth by the four screws which pass through the ftanch above 
 l L, one of the side steels. H represents a horse-shoe in the act of being grooved and punched. 
 
 2270. 2271. 
 
 The machine for grooving and punching is precisely as the one for rolling or drawing the shoe to the 
 required shape, with the exception of the upper swedge, as described above. 
 
 Fig. 2272, elevation of machine for bending horse-shoes, aaa the frame, b b the feet which support 
 the same, ccthe fly-wheel, d the connecting-rod. E the crank-shaft, ff the rack. gg the two 
 shafts. K the piece of iron round which the shoe is bent, having cogs on its edges shaped so as to fit 
 and mash into the piece K, while they revolve round on their respective shafts g g. M the wheel which 
 mashes and tits into the rack ff, and which communicates motion to the shafts g g and pieces of iron K 
 and L. If a button or nipper which takes hold at the end of the horse-shoe, in consequence of its 
 coming in contact with the piece of iron L, and holds it fast while it is in the act of bending ; and when 
 bent, said button or nipper strikes against the other side of piece L, which opens and lets the shoe drop. 
 It will be observed that the shafts g g and pieces of iron K and L do not make a full revolution 
 
 Fig 227 J-, plan of machine for bending horse-shoes, a a the frame, c the fly-wheel, e the crank-shaft 
 J. the connecting-rod. f a rack. M a wheel, whose cog mashes or fits into the cogs of the rack f 
 L the eccentric piece of iron which tits into the piece K, on which the shoe is formed, as seen at Figs 
 
HORSE-SHOE MACHINE. 
 
 2272 and 2273. 0, cap which confines the piece of iron while in the act of bending around the piece K, 
 as represented by the dotted lines at Fig. 2273. 
 
 Fig. 2273, section of the irons K and L. These two pieces, K and L, are fastened on the shaft g g 
 with their reversed sides up from what they appear in the drawing. The dotted lines represent a cap, 
 which is fastened on the piece of iron L with screw-bolts. This cap is about one inch thick, and serves 
 the purpose of keeping the iron close up while in the operation of bending around the piece of iron K. 
 
 2274. 
 
 The nature of the operation is as follows : — 
 
 Firstly : Fig. 2267 represents a section of the machine, having the upper roller i removed, so as to 
 show more distinctly the interior arrangement of the machine. Supposing a pulley of about four feet 
 diameter were bolted to the arms of the fly-wheel c, (which is omitted in the drawing,) and to which 
 motion were communicated by a leather strap or belt from a corresponding pulley on a shaft connected 
 with a water-wheel or other power ; it is evident that every revolution of the fly-wheel c would move 
 the carriage or moving -frame ff backwards and forwards, giving motion to the different parts of the 
 machine, as described and shown above. 
 
 Aud supposing the crank e e, by the connecting-rod d, had pulled or drawn the moving-frame ff 
 forward so as to cause the button or cam m to strike against the stop n, the cam o would also strike 
 against the stopp, and consequently push back or open the moving-jaw k, which turns on a pivot at 
 the other end. And supposing the moving-frame// were pushed back on the brasses x x, and towards 
 the last part of the motion a hot piece of iron (previously rolled to the desired size) were introduced be- 
 tween the side steels or irons 1 1, it is evident that the cutter-box uuu would strike against the stop w and 
 press up the chisel t against the chisel s, cutting off the necessary length of iron to make the shoe ; and 
 should the moving-frame be drawn forward by the crank e, the piece of iron, being confined bv the side 
 steels or irons 1 1 on the sides, would be rolled or shaped by the vertical steels or swedges E E, when 
 the cam m would strike against the stop n and permit o to open the jaw k and let the piece drop ; the 
 appearance and shape of which may be seen as represented by H, are so ground or shaped as to roll 
 or taper the piece H at each end intended for the heels of the shoe ; but it is found by experiment that 
 by using the iron square, and so grinding the steel or swedges E E as to flatten or roll down the- middle 
 of the piece, leaving the ends square for the heels of the shoe, makes the best shoe. 
 
 Secondly : Having explained the process of cutting the bar or rod into suitable lengths, and rolling or 
 shaping the same suitable for horse-shoes, it remains to describe the method of punching and grooving 
 them. And having already stated that the machine for grooving and punching is precisely the same 
 as the one above described for rolling or shaping the shoe, with the exception of the upper swedge, 
 which is substituted for the swedge represented in Fig. 2271 : supposing in a machine every way similar 
 to the one for rolling or shaping the shoe, as described under the first head, (with the exception of the 
 upper swedge, in lieu of which the one represented by Fig. 2270 was substituted,) the piece of iron 
 which came from the first machine were introduced between the side steels or irons l /, and the machine 
 set in motion, it is evident it would be grooved and punched and drop out of the machine on the moving- 
 jaw K being opened in the same manner as the piece dropped out from the first machine, as described 
 under the first head. 
 
 Thirdly : Having described the manner in which the piece is grooved and punched, it remains to 
 show how it is bent, which is the last operation. The piece of iron being now rolled or shaped as may 
 be desired for a horse-shoe, as also grooved and punched, is introduced into the machine, as shown and 
 described in Figs. 2272 to 2274. 
 
 We here copy Mr. Burden’s claim : 
 
 “ First : I claim the machine for rolling, drawing, or shaping horse-shoes, as described and represented 
 by Figs. 2267 to 2272, as a whole as there arranged ; namely, those parts called side steels or irons 1 1, 
 which confine the piece of iron intended for a horse-shoe, on the sides, while it is rolled or shaped by 
 the vertical swedges EE. I also claim the vibrating or reciprocating motion of moving-frame ff, 
 which gives motion to all the other parts of the machine, which enables the operator to feed up the iron 
 intended for horse-shoes to the stop A, cutting it off accurately, and rolling aud shaping them at the 
 same time. 
 
 And I claim the above-named reciprocating motion, whether it be by side steels or swedges, as 
 above named, or whether it be merely a pair of common grooved rollers, the one having a groove or 
 channel turned or cut the shape of the shoe, the other having a fongue so shaped as to tit the groove 
 exactly, the periphery of said tongue being so shaped as to roll the shoe thinner at some parts than at 
 others, as may be desired. 
 
 It will be observed that if two rollers, as aboved named, were connected together at the end by two 
 pinions, and on the other end of one were fastened a wheel similar to the wheel M on one of the shafts z 
 of the bending machine, having a jack operating into said wheel, connected to a crank in every respect 
 
26 
 
 HYDRODYNAMICS. 
 
 similar to the bending machine, it is evident that said rollers would move backwards and forwards, making 
 such part of a revolution as the length of the crank might give them. I therefore claim said recipro- 
 cating motion when applied to rolling or shaping horse-shoes by rollers. I do not claim the use of solid 
 rollers in rolling horse-shoes ; for I believe this has been done, or, rather, attempted to be done, and has 
 universally proved a failure, in consequence of not having reciprocating motion to enable the operator to 
 feed up the iron to a stop so as to insure the piece of iron intended for a horse-shoe being always in the 
 proper place to receive the impression from the roller. 
 
 Another reason why rolling horse-shoes by solid rollers has failed, is, that the tongue of the one and 
 socket of the other are liable to wear, and consequently have to be laid aside. Whereas, my method 
 of having the tongue or swedges, as also the socket, divided into sections, allows the whole being 
 ground, repaired, and moved at pleasure by screws, so as to insure the sides of the socket fitting close 
 to the tongue, as also having one side of the socket movable, to allow the shoes being discharged. I 
 also claim the method of having those parts of the machine which confine the iron on the sides, repre- 
 sented as side steels, marked 1 1, movable, so as to permit their being ground, when worn, at the 
 same time moving them close up to the swedges E E by screws. I also claim the plan of making the 
 rollers i i, with an open mortise, so as to permit the swedges D D being moved. In fine, I claim 
 the method of dividing the working parts which roll or shape the shoe into such sections as enables me 
 to grind, replace, and remove them at pleasure ; in lieu of solid rollers, which, when worn, have to be laid 
 aside altogether. I wish it to be particularly understood that I do not confine myself to the precise 
 method of operating the machine for rolling or shaping horse-shoes, as represented by the drawing 
 hereunto annexed ; as, in lieu of the frame ff being moved, it may be made stationary, and the rollers i i 
 moved backwards and forwards in slides, with corresponding movements given to the other parts, which 
 would give analogous results. 
 
 Secondly : I claim the machine for grooving and punching horse-shoes, as represented by the figures 
 and descriptions thereof. That is to say, I claim the manner of confining the piece of iron intended for 
 a horse-shoe, between the side steels 1 1, while in the act of grooving and punching, by the upper swedge 
 D having the pieces of steel fastened under the caps ii. I also claim the vibrating or reciprocating 
 motion of the machine in grooving and punching, for the same reasons as set forth in my claim to the 
 machine for rolling or shaping. I claim the manner of so shaping the edge of the steels as to leave 
 projections for the heads of the nails, as in all cases, even when made by hand, the groove is first 
 made, then the holes ; but by my plan I make both at once, which serves the double purpose of adding 
 strength to the punches, by being formed and composing part of the steel which forms the groove or 
 channel, as also performing both operations at once. I also claim the method of fastening the two 
 pieces of steel which groove and punch the shoe under the caps ii, which permits their being screwed 
 down by four screws, when necessary, in consequence of their becoming short by filing or other causes. 
 And as I deem the discovery of forming the projections or punches on the same piece of steel which 
 grooves or channels the shoe of great importance, I shall describe the manner in which it is done. Take 
 a piece of cast or other steel, previously rolled or hammered to about one-fourth of an inch in thickness, 
 about four inches wide, and as long as necessary, to form the groove on ope side of the shoe. Then 
 grind or reduce the edge by a file to the proper shape to form the groove : then mark the projections or 
 punches, filing down the spaces between the projections so as to give them sufficient length to form the 
 holes, which adds great strength to the punches, compared with the method of inserting small pieces oi 
 steel into a roller to form punches. 
 
 Thirdly : I claim the machine for bending horse-shoes, as represented and described by the drawings 
 thereof, in every particular as there arranged. And in addition to which, I claim any other method oi 
 bending horse-shoes, so long as the piece is taken hold of by one end, while the other is bent round the 
 mould, no matter whether the mould revolve round or is stationary, and the piece of iron is pulled or 
 bent round it. 
 
 I also claim, in a particular jnanner, the placing of the face of the mould downwards, so as to permit 
 the shoe to drop or discharge itself. I also claim the using of a piece of flat iron, as represented by the 
 dotted lines in Eig. 2273, for the purpose of keeping the shoe close up to the mould while in the act of 
 bending. I also claim the nipper or button, which closes and holds fast the end of the horse-shoe by 
 striking against the piece L while in the act of bending round the shoe shape K, and which opens in 
 consequence of its coming in contact with the other side of the piece L, and lets the shoe drop. 
 
 I also claim the manner of making the geering or wheels connected with the pieces of iron K and L 
 eccentric, or so shaped as to have the pitched line describe the same circle as the shoe. 
 
 HYDRAULIC RAM. See Ram. 
 
 HYDRODYNAMICS, is that branch of general mechanics which treats of the equilibrium and motion 
 of fluids. The terms hydrostatics and hydrodynamics have corresponding signification to the statics and 
 dynamics in the mechanics of solid bodies; viz., hydrostatics is that division of the science which treats 
 of the equilibrium of fluids, and hydrodynamics that which relates to their forces and motion. It is, 
 however, very usual to include the whole doctrine of the mechanics of fluids under the general term of 
 hydrodynamics, and to denote the divisions relative to their equilibrium and motion by the terms hydro- 
 statics and hydraulics. We adopt the latter division, and shall confine onrselves to a few of the 
 most usually received theoretical deductions, and state those rules which have been the result of a ju- 
 ciicious application of theory to experiment, as the subject itself is the one the least advanced of any 
 branch of mechanics, and we are as yet far from being in possession of the requisite data for a rigorous 
 solution of the problems which arise. Very many excellent treatises have been written, to which we 
 refer the scientific reader ; but the extent of the subject forbids the introduction of any of them into 
 this work, further than to select the best practical rules for the use of the mechanic. 
 
 Hydrostatics comprises the doctrine of the pressure and the equilibrium of non-elastic, fluids, as water 
 mercury, &c., and that of the w r eight and pressure of solids immersed in them. 
 
 1 . Fluids press equally in all directions, upwards, downwards, aslant or laterallv 
 
HYDRODYNAMICS. 
 
 27 
 
 This constitutes one essential difference between fluids and solids, solids pressing only downwards 01 
 ji the direction of gravity. 
 
 2. The upper surface of a gravitating fluid at rest is horizontal. 
 
 3. The jiressure of a fluid on every particle of the vessel containing it, or of any othei surface, real oi 
 imaginary, in contact with it, is equal to the weight of a column of the fluid, whose base is equal to that 
 particle, and whose height is equal to its depth below the upper surface of the fluid. 
 
 4. If, therefore, any portion of the upper part of a fluid be replaced by a part of the vessel, the pres- 
 sure against this from below will be the same which before supported the weight of the fluid removed, 
 and every part remaining in equilibrium, the pressure on the bottom will be the same as it would if the 
 vessel were a prism or a cylinder. 
 
 5. Hence, the smallest given quantity of a fluid may be made to produce a pressure capable of sus- 
 taining any proposed weight, either by diminishing the diameter of the column and increasing its height, 
 or by increasing the surface which supports the weight. It is upon this principle that the hydrostatic 
 press is made to operate. See Hydrostatic Press. 
 
 6. The pressure of a fluid on any surface, whether vertical, oblique, or horizontal, is equal to tin 
 weight of a column of the fluid whose base is equal to the surface pressed, and height equal to the dis 
 tance of the centre of gravity of that surface below the upper horizontal surface of the fluid. 
 
 7. Fluids of different specific gravities that do not mix, will counterbalance each other in a bent tube 
 when their heights above the surface of junction are inversely as their specific gravities. 
 
 A portion of fluid will be quiescent in a bent tube, when the upper surface in both branches oi the 
 tube is in the same horizontal plane, or is equidistant from the earth’s centre. And water poured down 
 one branch of such a tube, (whether it be of uniform bore throughout or not,) will rise to its own level 
 in the other branch. 
 
 Thus, water may be conveyed by pipes from a spring on the side of a hill, to a reservoir of equal 
 height on another hill. 
 
 8. The ascent of a body in a fluid of greater specific gravity than itself, arises from the pressure of 
 the fluid upwards against the under surface of the body. 
 
 The centre of pressure is that point of a surface against which any fluid presses, to which if a force 
 equal to the whole pressure were applied, it would keep the surface at rest, or balance its tendency to 
 turn or move in any direction. 
 
 The centre of pressure of a parallelogram, whose upper side is in the plane of the horizontal level of 
 the liquid, is at § of the line (measuring downwards) that joins the middles of the two horizontal sides 
 of the parallelogram. 
 
 If the base of a triangular plane coincides with the upper surface of the water, then the centre oj 
 pressure is at the middle of the line drawn from the middle of the base to the vertex of the triangle , 
 ]3ut, if the vertex of the triangle be in the upper surface of the water, while its base is horizontal, he 
 centre of pressure is at J of the line drawn from the vertex to bisect the base. 
 
 If b the breadth and d the depth of a rectangular gate, or other surface, exposed to the pressure of 
 water from top to bottom, then the entire pressure is equal to the weight of a prism of water "whose 
 content is \b d 2 . Or, if b and d be in feet, then the whole pressure — 311 b d 2 , in pounds. 
 
 If the gate be in form of a trapezoid, widest at top, then, if b and b be the breadths at the top and 
 bottom respectively, and d the depth, 
 
 Whole pressure in pounds = 31J [ J (b — b) -f- b] d 2 . 
 
 Floating bodies. — If any body float on a fluid, it displaces a quantity of the fluid equal to itself in weight. 
 
 Also, the centres of gravity of the body and of the fluid displaced, must, when ihe body is at rest, be 
 in the same vertical line. 
 
 If a vessel contain two fluids that will not mix, (as water and mercury,) and a solid of some interme- 
 diate specific gravity be immersed under the surface of the lighter fluid and float on the heavier, the 
 part of the solid immersed in the heavier fluid, is to the whole solid as the difference between the spe- 
 cific gravities of the solid and the lighter fluid is to the difference between the specific gravities of the 
 two fluids. 
 
 Tire buoyancy of casks, or the load which they will carry without sinking, may be estimated by reck- 
 oning 10 pounds avoirdupois to the ale gallon. 
 
 The buoyancy of pontoons may be estimated at about half a hundred weight for each cubic foot. 
 
 Thus a pontoon which contained 96 cubic feet, would sustain a load of 48 cwt. before it would sink. 
 This is an approximation, in which the difference between T 6 f and 4, that is, A of the whole weight, is 
 allowed for that of the pontoon itself. 
 
 Tins property has been successfully employed in pulling up piles in a river where the tide ebbs and 
 flows. A barge of considerable dimensions is brought over a pile as the water begins to rise ; a strong 
 chain which has been previously fixed to the pile by a ring, &c., is made to gird the barge, and is then 
 fastened. As the tide rises the vessel rises too, and by means of its buoyant force draws up the pile 
 with it. 
 
 In an actual case, a barge 50 feet long, 12 feet wide, 6 deep, and drawing 2 feet of water, was em- 
 
 50 V 1 o V 1 6 
 
 ployed. Here, 50 X 12 X (6 — 2) X :} = ’ ~ = 192 X 7 = 1344 -f 27? = 1371-J cwt. •= 
 
 66£ tons, nearly, the measure of the force with which the barge acted upon the pile. 
 
 Specific gravities. — If a body float on a fluid, the part immersed is lo the whole body as the specific 
 gravity of the body to the specific gravity of the fluid. (See Gravity and Specific Gravity.) 
 
 Hydraulics is that part of mechanical science which relates to the motion of non-elastic fluids, and the 
 forces with which they act upon bodies. 
 
28 
 
 HYDRODYNAMICS. 
 
 Motion and effluence of liquids. — 1. A jot of water, issuing from an orifice of a proper form, and di- 
 rected upwards, rises, under favorable circumstances, nearly to the height of the head of water in the 
 reservoir ; and since the particles of such a stream are but little influenced by the neighboring ones, 
 they may be considered as independent bodies, moving initially with the velocity which would be ac- 
 quired in falling from the height of the reservoir. And the velocity of the jet will be the same whatever 
 may be its direction. 
 
 2. Hence, if a jet issue horizontally from any part of the side of a vessel standing on a horizontal 
 plane, and a circle be described having the whole height of the fluid for its diameter, the fluid will reach 
 the plane at a distance from the vessel, equal to that chord of the circle in which the jet initially moves. 
 
 3. When a cylindrical or prismatic vessel empties itself by a small orifice, the velocity at the surface 
 is uniformly retarded ; and in the time of emptying itself, twice the quantity would be discharged if it 
 were kept full by a new supply. 
 
 4. But the quantity discharged is by no means equal to what would fill the whole orifice, with this 
 velocity. If the aperture is made simply in a thin plate, the lateral motion of the particles towards it 
 tends to obstruct the direct motion, and to contract the stream which has left the orifice, nearly in the 
 ratio of two to three. So that in order to find the quantity discharged, the section of the orifice must 
 be supposed to be diminished from 100 to 62 for a simple aperture, to 82 for a pipe of which the length 
 is twice the diameter, and in other ratios according to circumstances. 
 
 5. When a siphon, or bent tube, is filled with a fluid, and its orifices immersed in the fluids of different 
 vessels, if both surfaces of the fluids are in the same level, the whole remains at rest ; but if otherwise, 
 the longer column of fluid in the siphon preponderates, and the pressure of the atmosphere forces up 
 the fluid from the higher vessel, until the equilibrium is restored ; and the motion is the more rapid as 
 the difference of levels is greater: provided that the greatest height of the tube above the upj>er sur- 
 face be not more than a counterpoise to the pressure of the atmosphere. 
 
 6. If a notch or sluice in form of a rectangle be cut in the vertical side of a vessel full of water, or 
 any other fluid, the quantity flowing through it wall be § of the quantity which would flow through an 
 equal orifice placed horizontally at the whole depth, in the same time, the vessel being kept constantly full. 
 
 7. If a short pipe, elevated in any direction from an aperture in a conduit, throw the water in a par- 
 abolic curve to the distance or range r, on a horizontal plane passing through the orifice, and the greatest 
 height of the spouting fluid above that plane be h, then the height of the head of water above that con- 
 duit pipe may lie found, nearly : viz., by taking, first, 2 cot e = - — ; and, secondly, the altitude of the 
 head a = J r X cosec 2 e. 
 
 Ex. Suppose that r = 40 feet, and h = 18 feet. Then ~ — 1111111 1 = 2 cot 60° 57' : and 
 
 X cosec 2e = 20 X cosec 121° 54' = 20 X T177896 = 23'55'792 feet, height required. 
 
 Note. This result of theory will usually be found about 4-5ths of that which is furnished by 
 experiment. 
 
 Motion of water in conduit pipes and open canals, over weirs, dec. — 1. When the water from a reser- 
 voir is conveyed in long horizontal pipes of the same aperture, the discharges made in equal times are 
 nearly in the inverse ratio of the square roots of the lengths. 
 
 It is supposed that the lengths of the pipes to which this rule is applied are not very unequal. It is 
 an approximation not deduced from principle, but derived immediately from experiment. 
 
 2. Water running in open canals, or in rivers, is accelerated in consequence of its depth, and of the 
 declivity on which it runs, till the resistance increasing with the velocity, becomes equal to the accel- 
 eration, when the motion of the stream becomes uniform. 
 
 It is evident that the amount of the resisting forces can hardly be determined by principles already 
 known, and therefore nothing remains but to ascertain, by experiment, the velocity corresponding to 
 different declivities, and different depths of water, and to try, by multiplying and extending these ex- 
 periments, to find out the law which is common to them all. 
 
 The Chevalier Du Buat has given a formula for computing the velocity of running water, whether in 
 close pipes, open canals, or rivers, which, though it may be called empirical, is extremely useful hi 
 practice. 
 
 Let v be the velocity of the stream, measured by the inches it moves over in a second ; r a constant 
 quantity, viz., the quotient obtained by dividing the area of the transverse section of the stream, ex- 
 pressed in square inches, by the boundary or perimeter of that section, minus the superficial breadth 
 of the stream expressed in linear inches. 
 
 The mean velocity is that with which, if all the particles were to move, the discharge would be the 
 same with the actual discharge. 
 
 The line r is called by Du Buat the radius, and by Dr. Robison the hydraulic mean depth. As its 
 affinity to the radius of a circle seems greater than to the depth of a river, we shall call it, with the 
 former, the radius of the section. 
 
 Lastly, let s be the denominator of a fraction which expresses the slope, the numerator being unity, 
 that is, let it be the quotient obtained by dividing the length of the stream, supposing it extended in a 
 Itraight line, by the difference of level of its two extremities ; or, which is nearly the same, let it be the 
 co-tangent of the inclination or slope. 
 
 The above denominations being understood, and the section, as well as the velocity, being supposed 
 uniform, v in English feet, 
 
 307 ^(r-A) 
 s i -ilog.(s+ -|J) 
 
 
HYDRODYNAMICS. 
 
 29 
 
 orv = v /u- 
 
 When r and s are very great, 
 
 307 
 
 • I log. (s -f If) 
 
 A 
 
 i o. I 
 
 307 
 
 nearly. 
 
 S* 4 log. S 
 
 The logarithms understood here are the hyperbolic, and are found by multiplying the common loga 
 ?ithms by 2-3025851. 
 
 The slope remaining the same, the velocities are as y/ r — T ’ (| . 
 
 The velocities of two rivers that have the same declivity, are as the square roots of the radii of the!' 
 sections. 
 
 If r is so small, that r — > = 0, or u = -A, the velocity will be nothing, wbidi is agreeable to 
 experience ; for in a cylindric tube r = •$• the radius ; the radius, therefore, equal two-tenths ; so that 
 the tube is nearly capillary, and the fluid will not flow through it. 
 
 The velocity may also become nothing by the declivity becoming so small, that 
 
 — ^2 3=0 ; but 
 
 s — i log- (s + |f) 
 
 if — is less than , or than I- of an inch to an English mile, the water will have sensible motion. 
 
 s 500000 10 
 
 In a river, the greatest velocity is at the surface, and in the middle of the stream, from which it 
 diminishes towards the bottom and the sides, where it is least. It has been found by experiment, that, 
 if from the square root of the velocity in the middle of the stream, expressed in inches per second, unity 
 be subtracted, the square of the remainder is the velocity at the bottom. 
 
 Hence, if the former velocity be = v, the velocity at the bottom —v — 2 y/ v l. (A.) 
 
 The mean velocity, or that with which, were the whole stream to move, the discharge would be the 
 same with the real discharge, is equal to half the sum of the greatest and least velocities, as computer 
 in the last proposition. 
 
 The mean velocity is, therefore, =v — s/ v -f- (B.) 
 
 This is also proved by the experiments of Du Buat. 
 
 When the water in a river receives a permanent increase, the depth and the velocity, as in the ex 
 ample above, are the first things that are augmented. The increase of the velocity increases the action 
 on the sides and bottom, in consequence of which the width is augmented, and sometimes also, but 
 more rarely, the depth. The velocity is thus diminished, till the tenacity of the soil, or the hardness of 
 the rock, afford a sufficient resistance to the force of the water. The bed of the river then changes only 
 by insensible degrees, and, in the ordinary language of hydraulics, is said to be permanent, though in 
 strictness this epithet is not applicable to the course of any river. 
 
 When the sections of a river vary, the quantity of water remaining the same, the mean velocities are 
 inversely as the areas of the sections. 
 
 This must happen, in order to preserve the same quantity of discharge. 
 
 The following table, abridged from Du Buat, serves at once to compare the surface, bottom, and 
 mean velocities in rivers, according to the formulte (A) and (B). 
 
 VELOCITY IN INCHES. 
 
 VELOCITY IN INCHES. 
 
 Surface. 
 
 Bottom. 
 
 Mean. 
 
 Surface. 
 
 Bottom. 
 
 Mean. 
 
 4 
 
 i- 
 
 2-5 
 
 56 
 
 42-016 
 
 49-008 
 
 8 
 
 3-342 
 
 5-67 
 
 60 
 
 45-509 
 
 52-754 
 
 12 
 
 6-071 
 
 9-036 
 
 64 
 
 49- 
 
 56'5 
 
 16 
 
 9- 
 
 12-5 
 
 68 
 
 52-505 
 
 60-252 
 
 20 
 
 12-055 
 
 16-027 
 
 72 
 
 66-025 
 
 64-012 
 
 24 
 
 15194 
 
 19'597 
 
 76 
 
 59-568 
 
 67-7S4 
 
 28 
 
 18421 
 
 23-210 
 
 80 
 
 63-107 
 
 71-553 
 
 32 
 
 21-678 
 
 26-839 
 
 84 
 
 66-651 
 
 75-325 
 
 36 
 
 25- 
 
 30-5 
 
 88 
 
 70-224 
 
 79-112 
 
 40 
 
 28-345 
 
 34-172 
 
 92 
 
 73-788 
 
 82-894 
 
 44 
 
 31-742 
 
 37-871 
 
 96 
 
 77-370 
 
 86‘685 
 
 48 
 
 35-151 
 
 41-570 
 
 100 
 
 81- 
 
 905 
 
 52 
 
 38-564 
 
 45-282 
 
 
 
 
 The knowledge of the velocity at the bottom is of the greatest use for enabling us to judge of tne 
 action of the stream on its bed. 
 
 Every kind of soil has a certain velocity consistent with the stability of the channel. A greater ve- 
 locity would enable the waters to tear it up, and a smaller velocity would permit the deposition of 
 more movable materials from above. It is not enough, then, for (lie stability of a river, that the aceel- 
 
30 
 
 HYDRODYNAMICS. 
 
 erating forces are so adjusted to the size and figure of its channel that the current may be in train : it 
 must also be in equilibrio with the tenacity of the channel. 
 
 <We learn from the observations of Du Buat, and others, that a velocity of three inches per second at 
 the bottom will just begin to work upon the fine clay fit for pottery, and however firm and compact it 
 may be, it will tear it up. Yet no beds are more stable than clay, when the velocities do not exceed 
 this ; for the water soon takes away the impalpable particles of the superficial clay, leaving the particles 
 of sand sticking by their lower half in the rest of the clay, which they now protect, making a very per 
 manent bottom, if the stream does not bring down gravel or coarse sand, which will rub off this very 
 thin crust, and allow another layer to be worn off. A velocity of six inches will lift fine sand ; eight 
 inches will lift sand as coarse as linseed ; twelve inches will sweep along fine gravel ; twenty-four 
 inches will roll along rounded pebbles an inch diameter ; and it requires three feet per second at the 
 bottom to sweep along angular stones of the size of an egg. ( Robison on Rivers.) 
 
 Eytelwein, a German mathematician, has devoted much time to inquiries in hy- 
 drodynamics. His formulae apply to the motion of water; 1st, in a cylindric 
 tube ; 2d, in an open canal. 
 
 Let d be the diameter of the cylindric tube E F, h the total height F G of the 
 head of water in the reservoir above the middle of the orifice F, and l the length 
 E F of the tube, all in inches; then the velocity in inches with which the fluid will 
 issue from the orifice F will be 
 
 / 57 li d 
 
 v = 23J v' Z-t-57 d' 
 
 this multiplied into the area of the orifice will giye the quantity per second. 
 
 Let d = diameter of the pipe in inches, Q = the quantity of water in cubic feet discharged through 
 the pipe per minute, l = the length of the pipe in feet, and h = the difference of level between the 
 surface of the water in the reservoir and at the end of the pipe or the head ; then, any three of these 
 Quantities being given, the fourth may be determined from the following formulae: — 
 
 l 
 
 i=5 
 Q = \/ 
 
 •0448 Q 2 (l -f 4-2 d 
 h 
 
 hd ' ‘ 
 
 •0448 (l + 4-2 d) 
 
 h d 5 . , -0448 Q" ( l + 4-2 d) 
 
 — — 42 d h = t 
 
 •0448 Q a d 5 
 
 These formulas are more convenient expressed logarithmically, thus — 
 
 Log. d = i {2 log. Q + 2-6515 + log. (I + 4’2 d) — log. h } . 
 
 Log. Q = 4 {log. h + 5 log. d — 2-6515 — log. ( l + 4“2 d)\. 
 
 Log. I = log. li -f- log. d — 2-6515 — 2 log. Q (neglecting — 4'2 d). 
 
 Log. h = 2 log. Q -j- 2-6515 + log. (/ + 4'2 d) — 5 log. d. 
 
 When a pipe is bent in one or more places, then if the squares of the sines of the several changes oj 
 direction be added into one sum s, the velocity v will be found by the formula 
 
 * 
 
 
 548 d h 
 hl+^ds 
 
 l, h, d, and v, being all in inches. 
 
 Prouy gives a very safe formula for calculating the velocity of water in pipes, and it is very conve- 
 nient for use, and is reliable. 
 
 Y = velocity in feet per second. 
 
 D = diameter of pipe in feet. 
 
 H = the head, from surface of water in reservoir to the surface of water above the mouth of pipe. 
 
 L = the length of pipe. 
 
 S = - . Then V = 48 5254 ,/D S. The measures are all in feet. 
 
 L 
 
 For open canals. — Let v be the mean velocity of the current in feet, a area of the vertical section of 
 the stream, p perimeter of the section, or sum of the bottom and two sides, l length of the bed of the 
 canal corresponding to the fall h, all in feet : then 
 
 v = * / 9582 — , + 0-0111 — 0-109. 
 
 V pi 
 
 The experiments of M. Bidone, on the motion of water in canals, agree within the 80th part of the 
 •esults of computations from the preceding formulae. 
 
 We have used the following formula of Eytelwein, taken from the Edinburgh Encyclopedia, article 
 Hydrodynamics , for ascertaining the velocity of water in an open canal, and the results have been satis- 
 factory. 
 
 d == hydraulic mean depth , or mean radius in inches, called R in preceding formulae of Du Buat 
 
 f = fall in two mile of canal, in inches. 
 
 V = velocity in inches per second. 
 
 Then, V = 0-91 JJd. 
 
HYDRODYNAMICS. 
 
 81 
 
 For apertures in the sides or bottom of vessels . — If q equal the quantity of water discharged in cubic 
 feet per minute, v the velocity of the affluent water in feet per second through the aperture, a the area 
 of the aperture in square inches, and h the height from its centre to the surface of the water, we have 
 
 v = cifh ; and q = -4167 a c\fh ; 
 
 in which c is a constant quantity, depending upon the nature of the aperture, and the value of which, 
 for several different forms, is contained in the following table : — 
 
 Nature of the Orifices employed. 
 
 Ratio between the 
 theoretical and real 
 discharges. 
 
 Coefficients for 
 finding the velo- 
 cities in Eng. ft. 
 
 For the whole velocity due to the height 
 
 1 to 1-00 
 
 8-04 
 
 For wide openings whose bottom is on a level with that of 1 
 
 1 to 0'9C1 
 
 7-7 
 
 the reservoir j 
 
 
 
 For sluices with walls in a line with the orifice 
 
 1 to 0-961 
 
 7-7 
 
 For bridges with pointed piers 
 
 1 to 0-961 
 
 7-7 
 
 For narrow openings whose bottom is on a level with that of / 
 
 1 to 0-861 
 
 6-9 
 
 the reservoir \ 
 
 
 
 For smaller openings in a sluice with side walls 
 
 1 to 0-861 
 
 6-9 
 
 For abrupt projections and square piers of bridges 
 
 1 to 0-861 
 
 6-9 
 
 For openings in sluices without side walls 
 
 1 to 0'635 
 
 5*1 
 
 For an orifice in a thin plate 
 
 1 to 0-621 
 
 5-0 
 
 The following table of Smeaton is mainly the result of experiments. 
 
 Table, abridged from one by Mr. Smeaton , for showing the height of head necessary to overcome 
 the friction of water in horizontal pipes. 
 
 I i 
 
 Velocities per second of water in the pipes. 
 
 Ft. 
 
 0 
 
 in. 
 
 6 
 
 Ft. in. 
 1 0 
 
 Ft. in. 
 1 0 
 
 Ft. in. 
 2 0 
 
 Ft 
 
 in. 
 
 6 
 
 Ft. 
 
 3 
 
 in. 
 
 0 
 
 Ft. 
 
 3 
 
 in. 
 
 G 
 
 Ft. 
 
 4 
 
 in. 
 
 0 
 
 Ft. 
 
 4 
 
 in. 
 
 *0 
 
 Ft. 
 
 5 
 
 in. 
 
 0 
 
 pipes. 
 
 0 
 
 4-5 
 
 1 
 
 4-7 
 
 o 
 
 110 
 
 4 
 
 9-7 
 
 7 
 
 1-7 
 
 10 
 
 1-0 
 
 13 
 
 8-0 
 
 17 
 
 100 
 
 22 
 
 G-7 
 
 28 
 
 0-2 
 
 £ inch. 
 
 0 
 
 3(1 
 
 0 
 
 11-1 
 
 T 
 
 11-3 
 
 3 
 
 25 
 
 4 
 
 92 
 
 G 
 
 80 
 
 9 
 
 1-3 
 
 n 
 
 10-6 
 
 Is 
 
 0-5 
 
 18 
 
 8-1 
 
 # “ 
 
 0 
 
 2*o 
 
 0 
 
 8-4 
 
 i 
 
 5-5 
 
 2 
 
 4-9 
 
 3 
 
 69 
 
 5 
 
 0-5 
 
 6 
 
 10-0 
 
 8 
 
 11 0 
 
 11 
 
 3-4 
 
 14 
 
 o-o 
 
 1 “ 
 
 0 
 
 1*8 
 
 0 
 
 0-7 
 
 i 
 
 2-0 
 
 i 
 
 1 1-1 
 
 2 
 
 10-3 
 
 4 
 
 0-4 
 
 5 
 
 5*6 
 
 7 
 
 to 
 
 9 
 
 0-3 
 
 11 
 
 2-5 
 
 ' H 
 
 () 
 
 1-5 
 
 0 
 
 5'6 
 
 0 
 
 11-7 
 
 1 
 
 7>2 
 
 2 
 
 4-6 
 
 3 
 
 43 
 
 4 
 
 0-7 
 
 5 
 
 1 1-3 
 
 7 
 
 G-2 
 
 9 
 
 4-1 
 
 H “ 
 
 0 
 
 J*3 
 
 0 
 
 4*8 
 
 0 
 
 10-0 
 
 i 
 
 4-5 
 
 2 
 
 05 
 
 2 
 
 100 
 
 3 
 
 10-9 
 
 5 
 
 M 
 
 G 
 
 5-4 
 
 8 
 
 o-i 
 
 1-3- “ 
 
 0 
 
 it 
 
 0 
 
 4-2 
 
 0 
 
 8-7 
 
 i 
 
 24 
 
 i 
 
 9 4 
 
 o 
 
 6-2 
 
 3 
 
 5-0 
 
 4 
 
 55 
 
 5 
 
 7’7 
 
 7 
 
 o-o 
 
 2 
 
 0 
 
 1-0 
 
 0 
 
 3-7 
 
 0 
 
 7-8 
 
 i 
 
 0-8 
 
 i 
 
 7 0 
 
 2 
 
 2-9 
 
 3 
 
 04 
 
 3 
 
 110 
 
 5 
 
 0-1 
 
 G 
 
 2-7 
 
 21 “ 
 
 0 
 
 0-9 
 
 0 
 
 3-3 
 
 0 
 
 7-0 
 
 0 
 
 11-5 
 
 1 
 
 51 
 
 o 
 
 02 
 
 o 
 
 8-8 
 
 3 
 
 G-8 
 
 4 
 
 G1 
 
 5 
 
 7-2 
 
 2i u 
 
 0 
 
 0-7 
 
 0 
 
 2-8 
 
 0 
 
 50 
 
 0 
 
 9-G 
 
 1 
 
 2-3 
 
 I 
 
 8-2 
 
 o 
 
 3-3 
 
 2 
 
 11-7 
 
 3 
 
 91 
 
 4 
 
 8-0 
 
 3 “ 
 
 0 
 
 0*6 
 
 0 
 
 2-4 
 
 0 
 
 5-0 
 
 0 
 
 8-2 
 
 t 
 
 0-2 
 
 i 
 
 5-3 
 
 I 
 
 11-4 
 
 2 
 
 G-6 
 
 3 
 
 2-7 
 
 4 
 
 00 
 
 3i “ 
 
 0 
 
 O-Ii 
 
 0 
 
 2-1 
 
 0 
 
 4-4 
 
 0 
 
 7*2 
 
 0 
 
 10-7 
 
 i 
 
 31 
 
 l 
 
 8-5 
 
 2 
 
 2-7 
 
 2 
 
 9-8 
 
 3 
 
 GO 
 
 4 “• 
 
 0 
 
 0*5 
 
 0 
 
 1-9 
 
 0 
 
 39 
 
 0 
 
 6-4 
 
 0 
 
 9-5 
 
 i 
 
 1-4 
 
 l 
 
 G-2 
 
 i 
 
 11-8 
 
 2 
 
 G1 
 
 3 
 
 1-4 
 
 41 
 
 0 
 
 04 
 
 0 
 
 1-7 
 
 0 
 
 3-5 
 
 0 
 
 5-8 
 
 0 
 
 8 0 
 
 i 
 
 o-i 
 
 l 
 
 4-4 
 
 i 
 
 9-4 
 
 o 
 
 3-1 
 
 2 
 
 9-G 
 
 5 u . 
 
 0 
 
 0*4 
 
 0 
 
 1 4 
 
 0 
 
 2-9 
 
 0 
 
 4-8 
 
 0 
 
 71 
 
 0 
 
 10-1 
 
 l 
 
 1-7 
 
 i 
 
 5 8 
 
 I 
 
 10-6 
 
 2 
 
 4-0 
 
 G 
 
 0 
 
 0-3 
 
 0 
 
 1-2 
 
 0 
 
 25 
 
 0 
 
 4-1 
 
 0 
 
 o-t 
 
 0 
 
 8-6 
 
 0 
 
 11-7 
 
 1 
 
 3-3 
 
 i 
 
 7-3 
 
 o 
 
 o-o 
 
 7 u 
 
 0 
 
 0*3 
 
 0 
 
 l-o 
 
 0 
 
 2'2 
 
 0 
 
 30 
 
 0 
 
 54 
 
 0 
 
 7-0 
 
 0 
 
 10-2 
 
 1 
 
 1-4 
 
 i 
 
 4-9 
 
 i 
 
 90 
 
 8 “ 
 
 0 
 
 0 25 
 
 0 
 
 0-9 
 
 0 
 
 1-9 
 
 0 
 
 3-2 
 
 0 
 
 4-8 
 
 0 
 
 6*7 
 
 0 
 
 9*1 
 
 0 
 
 11-9 
 
 i 
 
 3-0 
 
 i 
 
 6-7 
 
 9 “ 
 
 0 
 
 0-2 
 
 0 
 
 0-8 
 
 0 
 
 1-7 
 
 0 
 
 2-9 
 
 0 
 
 4-3 
 
 0 
 
 6*0 
 
 0 
 
 8-2 
 
 0 
 
 10-7 
 
 i 
 
 1*5 
 
 i 
 
 4-8 
 
 10 “ 
 
 () 
 
 0-2 
 
 0 
 
 0 8 
 
 0 
 
 1-6 
 
 0 
 
 2-6 
 
 o 
 
 3*9 
 
 0 
 
 5*5 
 
 0 
 
 7-5 
 
 0 
 
 9-7 
 
 l 
 
 0-3 
 
 i 
 
 3-3 
 
 11 “ 
 
 0 
 
 019 
 
 0 
 
 07 
 
 0 
 
 1-5 
 
 0 
 
 2-4 
 
 0 
 
 3 - G 
 
 0 
 
 5*0 
 
 0 
 
 G-8 
 
 0 
 
 8-9 
 
 0 
 
 11-3 
 
 i 
 
 2-0 
 
 12 “ 
 
 Look for the velocity of water in the pipe in the upper row, and in the column below it, and opposite 
 to the given diameter of the pipe standing in the last column, will be found the perpendicular height of 
 a column or head, in feet, inches, and tenths, requisite to overcome the friction of such pipe for 100 feet 
 in length, and obtain the given velocity. 
 
 From the present standard work, Lowell Hydraulic Experiments, by Jas. B. Francis, Esq., we extract 
 the following on weirs : 
 
 The formula proposed for weirs of considerable length in proportion to the depth upon them, and hav- 
 ing complete contraction, (as first suggested to the author by Mr. Boyden in 1846,) is 
 
 Q = C {l— bn h) h* ; 
 
 m which 
 
 Q = the quantity discharged in cubic feet per second. 
 
 C — a constant coefficient. 
 
 I = the total length of the weir in feet. 
 b = a constant coefficient. 
 
 n = the number of end contractions. In a single weir having complete contraction, n always 
 equals 2, and when the length of the weir is equal to the width of the canal leading to 
 it, n — 0. 
 
 h = the depth of water flowing over the weir, taken far enough upstream from the weir, to be un- 
 affected by the curvature in the surface caused by the discharge. 
 a — a constant power. 
 
32 
 
 HYDRODYNAMICS. 
 
 By experiments the numerical values were determined as follows: 
 
 Q = 3.33 (A — 0.1 nH)H^: 
 the English foot being the unit of measure. ' 
 
 This formula is only applicable to rectangular weirs, made in the side of a dam, which is vertical on 
 the upstream side, the crest of the weir being horizontal, and the ends vertical ; also, the edges of the 
 orifice presented to the current must be sharp ; for, if bevelled or rounded off in any perceptible degree, 
 a material effect will be produced on the discharge ; it is essential, moreover, that the stream should 
 touch the orifice only at these edges, after passing which it should be discharged through the air, in the 
 same manner as if the orifice was cut in a thin plate. The formula is not applicable to cases in which 
 the depth on the weir exceeds one third of the length ; nor to very small depths. There seems ijo rea- 
 son why it should not be applied with safety to any depths between 6 inches and 24 inches. 
 
 The height of the surface of the water in the canal, above the crest of the weir, is to be taken for the 
 depth upon the weir ; this height should be taken at a point far enough from the weir to be unaffected 
 by the curvature caused by the discharge ; if more convenient, it may be taken by means of a pipe 
 opening near the bottom of the canal near the upstream side of the weir, which pipe may be made to 
 communicate with a box placed in any convenient situation ; and if the box and pipe do not leak, the 
 height may be observed in this manner, very correctly. However the depth may be observed, it may 
 require to be corrected for the velocity of the water approaching the weir. 
 
 The end contraction must either be complete, or entirely suppressed ; the necessary distance from the 
 6ide of the canal or reservoir to the end of the weir, in order that the end contraction may be complete, 
 is not definitely determined. In cases where there is end contraction, we may assume a distance from 
 the side of the canal to the end of the weir equal to the depth on the weir, as the least admissible, in 
 order that the proposed formula may apply. 
 
 As to the fall below the weir, requisite to give a free discharge to the water, it is not definitely deter- 
 mined ; it appears that when the sheet, passing the weir, falls into water of considerable depth, the 
 depth on the weir being about 0.85 feet, no difference is perceptible in the discharge, whether the water 
 is 1.05 feet or 0.235 feet below the crest of the weir; it is very essential, however, in all cases, that the 
 air under the sheet should have free communication with the external atmosphere. With this precau- 
 tion it appears that, if the fall below the crest of the weir is not less than half the depth upon the weir, 
 the discharge over the weir will not be perceptibly obstructed. If the sheet is of very great length, 
 however, more fall will be necessary, unless some special arrangement is made to supply air to the space 
 under the sheet at the places that would otherwise not have a free communication with the atmosphere. 
 
 In respect to the depth of the canal leading to the weir, experiments show that, with a depth as 
 small as three times that on the weir, the proposed formula agrees with experiment, within less than one 
 per cent. ; this proportion may be taken as the least admissible, when an accurate gauging is required. 
 
 It not unfrequently happens that, in consequence of the particular form of the canal leading to the 
 weir, or from other causes, the velocity of the water in the canal is not uniform in all parts of the sec- 
 tion ; this is a frequent cause of serious error, and is often entirely overlooked. If great irregularities 
 exist, they should be removed by causing the wafer to pass through one or more gratings, presenting 
 numerous small apertures equally distributed, or otherwise, as the case may require, through which the 
 water may pass under a small head ; these gratings should be placed as far from the weir as practi- 
 cable. 
 
 If the canal leading to the weir has a suitable depth, it will be requisite only when great precision is 
 required, to correct the depth upon the weir for the velocity of the water in the canal bv the formula 
 (D). 
 
 li being the head due to the velocity with which the water approaches the weir : — 
 
 II' .= — 
 
 Substituting IT for II in the previous formula, we obtain the flow increased for the velocity with which 
 the water approaches the weir. 
 
 Of gauging the flow of water in open canals of uniform rectangular section. — It has been frequently 
 found convenient at Lowell, to gauge large streams of water by causing them to flow through short rec- 
 tangular canals of uniform section, and a particular method of obtaining the mean velocity has been 
 practised, which will now be de c ’ribed. 
 
 A convenient part of the feeding canal is selected and lined with timbers and planks, so as to make a 
 smooth and uniform rectangular channel; this is called a flume. The mean velocity is obtained by 
 means of tubes, loaded at one end, so that they may float in nearly a perpendicular position, the lower 
 ends just clearing the bottom of the flume ; these tubes are put in near the upper end of the flume, and 
 from the observed paths and velocities that they assume through a defined portion of the length of the 
 flume, a mean velocity is deduced. The times of the transits are observed by the same chronometer, 
 the signals being made by an electric telegraph erected for the purpose. The telegraph used for this 
 purpose is a very simple apparatus ; the circuit is formed by an insulated copper wire, about ^ of an 
 inch in diameter, and the electric current is maintained by a small galvanic battery. "Whenever the cir- 
 cuit is broken, a small electro-magnet becomes demagnetized, which causes a slight blow to be struck 
 on a vertical glass plate, placed near the observer, who notes the times of the transits. The tubes are 
 cylinders, made of tinned plate, about two inches in diameter, and of a length usually a little exceeding 
 the depth of the water in the flume By a comparison of the results obtained by gauging, by the floats 
 and by weir, the error in assuming the average velocity of the floats for that of the stream, was found 
 to be correct within a trifling per centage. 
 
HYDRO-ELECTRICAL MACHINE. 
 
 33 
 
 Contrivances to measure the velocity of running waters. — For these purposes, various contrivances 
 have been proposed, of which two or three may be here described. 
 
 Suppose it be the velocity of the water in a river that is required; or, indeed, both the velocity and 
 the quantity which flows down it in a given time. Observe a place where the banks of the river are 
 steej) and nearly parallel, so as to make a kind of trough for the water to run through, and by taking 
 the depth at various places in crossing make a true section of the river. Stretch a string at right angles 
 over it, and at a small distance another parallel to the first. Then take an apple, an orange, or other 
 small ball, just so much lighter than water as to swim in it, or a pint or quart bottle partly filled with 
 water, and throw it into the water above the strings. Observe when it comes under the first string, by 
 means of a quarter second pendulum, a stop-watch, or any other proper instrument ; and observe like- 
 wise when it arrives at the second string. By this means the velocity of the upper surface will be 
 obtained. And the section of the river at the second string must be ascertained by taking various 
 depths, as before. If this section be the same as the former, it may be taken for the mean section : if 
 not, add both together, and take half the sum for the mean section. Then the area of the mean section 
 in square feet being multiplied by the distance between the strings in feet, will give the contents of the 
 water in solid feet, which passed from one string to the other during the time of observation ; and this 
 by the rule of three may be adapted to any other portion of time. The operation may often be greatly 
 abridged by taking notice of the arrival of the floating body opposite two stations on the shore, espe- 
 cially when it is not convenient to stretch a string across. 
 
 M. Pitot invented a stream measurer of a simple construction, by means of which the velocity of any 
 part of a stream may readily be found. This instrument is composed of two long tubes of glass open 
 at both ends: one of these tubes is cylindrical throughout; the other has one of its extremities bent 
 into nearly a right angle, and gradually enlarges like a funnel, or the mouth of a trumpet : these tubes 
 are both fixed in grooves in a triangular prism of wood ; so that their lower extremities are both on the 
 same level, standing thus one by the side of the other, and tolerably well preserved from accidents. 
 The fl ame in which these tubes stand is graduated, close by the side of them, into divisions of inches 
 and lines. 
 
 To use this instrument, plunge it perpendicularly into the water, in such manner that the opening of 
 the funnel at the bottom of one of the tubes shall be completely opposed to the direction of the cur- 
 rent, and the water pass freely through the funnel up into the tube. Then observe to what height the 
 water rises in each tube, and note the difference of the sides ; for this difference will be the height due 
 to the velocity of the stream. It is manifest, that the water in the cylindrical tube will be raised to the 
 same height as the surface of the stream, by the hydrostatic pressure : while the water entering from 
 the current by the funnel into the other tube, will be compelled to rise above that surface by a space 
 at which it will be sustained by the impulse of the moving fluid : that is, the momentum of the stream 
 will be in equilibrio with the column of water sustained in one tube above the surface' of that in the 
 other. In estimating the velocity by means of this instrument, we must have recourse to theory as 
 corrected by experiments. Thus, if h, the height of the column sustained by the stream, or the differ- 
 ence of heights in the two tubes, be in feet, we shall have v = 6‘5 f h, nearly, the velocity, per second, 
 of the stream ; if h be in inches, then v = 22'47 -f h, nearly : or further experiments made with the 
 instrument itself may a little modify these coefficients. 
 
 Note. In an example like this, it is a good approximation, to multiply continually together, the area 
 of the orifice, the number 336, (336 = 5'6 X 66,) and the square root of the dej)th in feet of the middle 
 of the orifice. 
 
 Thus, in the preceding example, it will be 4 X i X 336 X x/4'25 = j X 336 X 2 062 = 173'2 cubic 
 feet. 
 
 The less the height of the orifice compared with its depth under the water, the nearer will the result 
 thus obtained approach to the truth. If the height of the orifice be such as to require consideration, the 
 principle of Art. 6, page 17, may be blended with this rule. 
 
 Thus, applying this rule to Ex. 2, we shall have area X %/ depth X 336 X | = 9 X 3 X 224 = 6048, 
 for the cubic feet discharged. This is less than the former result by about its 900th part. It is, there- 
 fore, a good approximation, considering its simplicity : it may, in many cases, supersede the necessity of 
 recurrence to tables. 
 
 HYDRO-ELECTRICAL MACHINE. The production of electricity by the passage of steam through 
 a small jet, was unknown till 1840. It is now generally concluded that it is the effect of the friction 
 of globules of water against the sides of the opening, urged forward by the rapid passage of the 
 steam ; the effect of this is to render the steam or water positive, and the pipes from which it issues 
 negative. 
 
 Fig. 2275 represents this machine, as manufactured by Benjamin Pike, Jr., of 294 Broadway, New 
 York, in which A A, die., are six green glass supports, three feet long ; B is a cylindrical tubular boiler 
 of rolled iron-plate, § inch thick ; its extreme length is seven feet six inches, one foot of which is occu- 
 pied by the smoke-chamber, making the actual length of the boiler six and a half feet ; its diameter 
 three and a half feet. The furnace D and ash-hole C are contained within the boiler, and are furnished 
 with a metal screen to be applied for the purpose of excluding the light during the progress of one 
 class of experiments; F is the water-gage; E the feed-valve; JJ are two tubes leading from the 
 valves K K to the two tubes H ; A and I are forty-six bent iron tubes, terminating in jets, either half or 
 the whole of which may be opened by means of the lever G G ; L is a valve for liberating steam during 
 the existence of the maximum pressure ; M is the safety-valve ; N is a cap covering a jet, that is em- 
 ployed for illustrating a certain mechanical action of a jet of steam ; O is the first portion of the funnel ; 
 P the second portion, which slides into itself by a telescope joint, so that the boiler may be insulated 
 when the experiments commence. The boiler is cased in wood. 
 
 Fig. 227 6, which may be called the prime conductor, but which is not used for the purpose, is a zinc 
 case, furnished with four rows of points. It is placed in front of the jets, in order to collect the elec 
 Vol. II.— 3 
 
34 
 
 HYDRO-EXTRACTOR. 
 
 tricity from the ejected vapor, and thus prevent its returning to restore the equilibrium of the boiler 
 The maximum pressure at the commencement of the experiments is 80 pounds, which gradually gets 
 reduced to 40 pounds, or lower. The portion of the apparatus which is peculiarly connected with the 
 generation of the electricity, is a series of bent tubes with their attached jets. Each jet consists of a brass 
 socket, containing a cylindrical piece of partridge-wood, with a circular hole or passage through it, £ of 
 an inch in diameter, into which the steam is admitted through an aperture. The peculiar shape of this 
 aperture appears to derive its efficacy from the tendency it gives the steam to spread out in the form 
 of a cup, on entering the wooden pipe, and by that means to bring it and the particles of water of 
 which it is the carrier, into very forcible collision with the rubbing surface of the wood. 
 
 The electricitj' produced by this engine is not so remarkable for its high intensity, as for its enormous 
 quantity. In no case, antecedent to this, has the electricity of tension taken so rapid a stride towards 
 assimilating with galvanic electricity. Mr. Faraday’s experiments on the identity of the electricities had 
 shown how small was the quantity obtained from the best machines ; and had given good reason to 
 expect that chemical effects would be exalted when the quantity could be increased. And such is the 
 case here ; a very remarkable experiment in illustration of this is, that not only is gunpowder ignited 
 by the passage of the spark, but even paper and wood shavings will be inflamed when placed in the 
 course of the spark passing between two points — such an effect was never before produced with 
 common electricity. In like manner, chemical decompositions are effected much more readily by means 
 of the hydro-electric, than by that from the common machine. 
 
 HYDRO-EXTRACTOR. An apparatus 
 for removing liquids or moisture from yarns fi 2277. 
 
 or cloths in the process of manufacture. 
 
 The main feature or principle of the machine 
 is extremely simple, consisting merely of a 
 circular open wire-basket, in which the wet 
 cloths are placed as uniformly as possible, 
 and which is then made to revolve with such 
 rapidity that the moisture is thrown out 
 by the centrifugal force through the inter- 
 stices of the basket. As the vis inertias 
 prevents the instant communication of a 
 sufficient velocity to the basket loaded with 
 heavy goods, various expedients have been 
 resorted to to make communicated velocity 
 progressive. The contrivances for this pur- 
 pose, on the original English patent, are ex- 
 tremely complicated; but the arrangement 
 shown in Fig. 2217, (which is an exterior 
 view of the machine and the driving appa- 
 ratus,) is much more simple, and perfectly 
 effective. It is the invention of M. C. Bry- 
 ant, of Lowell, Massachusetts. The whole 
 machine rests on two square bed-stones ; 
 the outside of the case, or tub, is only shown 
 in the figure, within which the wire-basket, 
 open at the top for the reception of the 
 goods, revolves on a vertical shaft ; to this 
 shaft motion is communicated from the 
 horizontal shaft beneath the tub by means 
 of bevel-geers. On the extremity of this 
 horizontal shaft is fixed the driving-pulley, 
 
 'as shown in the figure.) This pulley is of 
 
 vi'-v Stone 
 2C./V. 
 
HYDROMETER. 
 
 oD 
 
 the form usually employed on small tilt or trip hammers ; a belt passing round this pulley, and contin 
 ually moving, communicates motion to the pulley ■whenever a binder brings the belt in close contact 
 with its periphery. The binder is attached to an extremity of an oscillating frame, suspended from the 
 top of the tub, as shown in the figure. The binder presses against the belt so as to communicate motion 
 to the pulley. To stop the motion, the upper end of the oscillating binder-frame is pressed down by a 
 handle; the binder relieves the belt, and a rope attached to the periphery of a small pulley on the 
 binder-frame passing over a pulley fixed on the horizontal driving-shaft, and fastened at the other end 
 to the bottom of the tub, acts as a friction-brake to retard the motion of the shaft, and consequently ot 
 the basket. To keep the binder-frame in extreme positions a movable weight is placed on the handle 
 rod at the top of the frame, which slides from one end to the other of the rod, as the binder is raised or 
 depressed. 
 
 The basket in this hydro-extractor is about three and a half feet in diameter; and in full action, 
 should make about 800 revolutions per minute. The driving-belt is about eight inches wide ; the 
 driving-pulley eighteen inches diameter. 
 
 This machine is in operation at the Bay State Mills, in Lawrence, and at the carpet mill in Lowell ; 
 and machines similar in the main principle are employed in many of the mills in this country, and 
 give complete satisfaction. 
 
 HYDROMETER. An instrument for determining the specific gravities of liquids, and thence the 
 strength of spirituous liquors ; these being inversely as their specific gravities. V arious instruments of 
 different forms have been proposed for ascertaining readily the specific gravities of fluids, but only two 
 or three of them are deserving of description. 
 
 The hydrometer represented in Fig. 2278 consists of a hollow glass ball B, with a smaller ball 0 
 appended to it, and which, from its superior weight, serves to keep the instrument in a vertical position, 
 to whatever depth it may be immersed in a liquid. From the large ball rises a cylindrical stem a d, on 
 which are marked divisions into equal parts ; and the depth to which the stem will sink in water, or 
 any other liquid fixed on as a standard of specific gravity, being known, the depth to which it sinks in a 
 liquid whose specific gravity is required, will indicate, by the scale, how much greater or less it is than 
 that of the standard liquid. 
 
 Those most celebrated are the scales of Baume, Cartier, Twaddell, and Guy Lussac. Most of these 
 scales are arbitrary, and formed after the ideas of their projectors, but having no particular reference by 
 which they may be understood. 
 
 The centesimal hydrometer, by Guy Lussac, is an exception, the extreme points 22, b. 
 
 being water and absolute alcohol ; this space is divided into one hundred parts, 
 thus showing in alcoholic mixtures the per rentage of alcohol in the liquid. They 1 
 
 are made of glass, brass, and silver, usually from six to ten inches long, of the 1 
 
 form represented in the cut, the graduations being marked on the stem. 
 
 Table showing the Comparative Scales of Guy Lussac and Baume, with the 
 Specific Gravities and Proof, at the Temperature of 60°. 
 
 Guy Lussac’s Scale. 
 
 Baum 6 ’s Scale. 
 
 Specific Gravity. 
 
 Proof. 
 
 
 100 
 
 45 
 
 796 
 
 100 ' 
 
 
 
 95 
 
 40 
 
 815 
 
 92 
 
 
 "o 
 
 90 
 
 85 
 
 36 
 
 33 
 
 833 
 
 848 
 
 82 
 
 72 
 
 fep -3 
 G 0 
 
 s 
 
 80 
 
 31 
 
 863 
 
 62 
 
 O s_ 
 
 a 
 
 . 75 
 
 28 
 
 876 
 
 52 
 
 s > 
 
 | 
 
 70 
 
 26 
 
 889 
 
 42 
 
 Pm 0 
 
 P- 
 
 65 
 
 24 
 
 901 
 
 32 
 
 
 o 
 
 60 
 
 23 
 
 912 
 
 22 4thpi;oof. 
 
 <D 
 
 tl) 
 
 55 
 
 21 
 
 923 
 
 12 
 
 
 03 
 
 50 
 
 19 
 
 933 
 
 0 Proof. 
 
 O 
 
 45 
 
 18 
 
 942 
 
 S') 
 
 
 
 40 
 
 17 
 
 951 
 
 18 
 
 u , . 
 
 <D 
 
 35 
 
 16 
 
 958 
 
 29 
 
 ►i> 8 
 
 
 30 
 
 15 
 
 964 
 
 35 
 
 P-i 
 
 
 25 
 
 14 
 
 970 
 
 48 ) 
 
 
 Explanation of Baume’s scale . — Manufacturers who employ BaumtS’s hydrometer, or have occasion 
 to know the value of the degrees on his scale, may find the following formula useful : — 
 
 Let B = Baum6’s degrees, and 100 = water. Then 
 
 144 
 
 Specific gravity = 1 j 4 _ B ' 
 
 That is to say, 144 divided by the difference between 144 and the given degree of Baume, is the specific 
 gravity in question, stated in reference to water assumed = 100. Thus, suppose Baume = 66°. Then 
 
 144 144 • 
 
 - — — or — — = 1-846 = specific gravitv. 
 
 144— 66 78 1 ° 
 
 Specific gravity 
 
86 
 
 HYDROSTATIC PRESS. 
 
 Scale of Specific Gravities indicated by Twaddell’ s Scale. 
 
 Twaddell. 
 
 Sp . Gr . 
 
 Twaddell. 
 
 Sp . Gr . 
 
 Twaddell. 
 
 Sp . Gr . 
 
 Twaddell. 
 
 Sp . Gr . 
 
 0 
 
 ....1000 
 
 50 
 
 ....1250 
 
 100 
 
 ....1500 
 
 150 
 
 ....1750 
 
 10 
 
 
 60 
 
 
 110 
 
 
 160 
 
 ....1800 
 
 20 
 
 ....1100 
 
 70 
 
 ....1350 
 
 120 
 
 ....1600 
 
 170 
 
 ....1850 
 
 80 
 
 ....1150 
 
 80 
 
 ....1400 
 
 130 
 
 ....1650 
 
 180 
 
 ....1900 
 
 40 
 
 ....1200 
 
 90 
 
 
 140 
 
 ....1700 
 
 190 
 
 ....1950 
 
 Hydrometer with weights. — There is a variety of kinds of hydrometers, with weights ; the principal 
 ones are Diea’s and Sikes's. They are used for ascertaining the strength of spirituous liquors. 
 
 Another easy method of determining the densities of different liquids, frequently practised, is by means 
 of a set of glass beads previously adjusted and numbered. Thrown into any liquid, the heavier balls 
 sink and the lighter float at the surface ; but one of them approaching the density of the liquid will be 
 in a state of indifference as to buoyancy, or will float under the surface. The number on this ball indi- 
 cates, in thousandth parts, the specific density of the liquid. 
 
 HYDROSTATIC PRESS. If there be any number of pistons of different magnitudes, any how 
 applied to apertures in a cylindrical vessel filled with an incompressible and non-elastic fluid, the 
 forces acting on the pistons to maintain an equilibrium, will be to one another as the areas of the 
 respective apertures, or the squares of the diameters of the pistons. 
 
 Let A B C D represent a section passing along the axis of a cylindrical vessel filled 
 with an incompressible and non-elastic fluid, and let E F be two pistons of different mag- 
 nitudes, connected with the cylinder and closely fitted to their respective apertures or 
 orifices ; the piston F being applied to the aperture in the side of the vessel, and the pis- 
 ton E occupying an entire section of the cylinder or vessel, by which the fluid is con- 
 tained. 
 
 Then, because by the nature of fluidity, the pressures on every part of the pistons E and F, are 
 mutually transmitted to each other through the medium of the intervening fluid ; it follows that these 
 pressures will be in a state of equilibrium when they are equal among themselves. 
 
 Now, it is manifest, that the sum of the pressures propagated by the piston E, is proportional to the 
 area of a transverse section of the cylinder ; and in like manner the sum of the pressures propagated by 
 the piston F is proportional to the area of the aperture which it occupies ; consequently, an equilibrium 
 must obtain between these pressures when the forces on the pistons are to one another, respectively, 
 as the areas of the apertures or spaces which they occupy. 
 
 Hence it appears, that by taking the areas of the pistons E and F, in a proper ratio to one another, 
 we can, by means of an incompressible fluid, produce an enormous compression, and that too by the 
 application of a very small force. 
 
 Put P = the force or pressure on the piston E, 
 
 A = the area of the orifice which it occupies, 
 p = the pressure on the piston F, and 
 a = the area of the orifice or space to which it is fitted : 
 then, according to the principle announced in the foregoing proposition and demonstrated above, we 
 shall obtain 
 
 a : A : : p : P. 
 
 But because, by the principles of mensuration, the areas of different circles are to one another as the 
 squares of their diameters ; if, therefore, we substitute d 2 and D 2 respectively for a and A in the above 
 analogv, we shall have 
 
 <T - : D 2 : : p : P ; 
 
 and from this, by making the product of the mean terms equal to the product of the extremes, we get 
 the general equation, 
 
 p D ! = P d 2 ;A) 
 
 This is the principle upon which depends the construction and use of that very powerful instrument, the 
 Hydrostatic Press , first brought into notice about the year 1196, by Joseph Bramah, Esq., of London. 
 
 The improvement introduced by Mr. Bramah, consisted in the application of the common forcing- 
 pump to the injection of water, or some other incompressible and non-elastic fluid, into a strong metallic 
 cylinder, truly bored and furnished with a movable piston, made perfectly water-tight by means of 
 leather collars or packing, neatly fitted into the cylinder. 
 
 The proportion which subsists between the diameter of this piston, and that of the plunger in the 
 forcing-pump, constitutes the principal element by which the power of the instrument is calculated; for, 
 by reason of the equal distribution of pressure in the fluid, in proportion as the area of the transverse 
 section of the one exceeds the area of a similar section of the other, so must the pressure sustained by 
 the one exceed that sustained by the other. 
 
 Therefore, if the piston F, in the preceding diagram, be assimilated to the plunger in the barrel of a 
 forcing-pump, and the piston E to that in the cylinder of the hydrostatic press ; then, the equation (A ) 
 involves every particular respecting the power and effects of the engine. 
 
 Example. If the diameter of the cylinder is 5 inches, and that of the forcing-pump one inch ; what 
 is the pressure on the piston in the cylinder, supposing the force applied on the plunger or smaller pis- 
 ton to be equivalent to 150 lbs. ? 
 
 Here we have given D = 5 inches, d — 1 inch, and p = 750 lbs. ; therefore, by substitution, equation 
 (A) becomes 
 
 PD 2 
 
 5 2 X 750 = P XI 2 ; that is, P = — = 18,750 lbs. 
 
 a ■ 
 
HYDROSTATIC PRESS. 
 
 37 
 
 Ride. — Multiply the square of the diameter of the cylinder by the pressure on the piston, of the forc- 
 ing pump, and divide the product by the square of its diameter, and the quotient will express the in- 
 tensity of the pressure on the piston of the cylinder. 
 
 , _ P d 2 
 
 * jyi ’ or, in words : — 
 
 Rule. — Multiply the given pressure on the piston of the cylinder by the square of the diameter of the 
 forcing pump, and divide the product by the square of the diameter of the cylinder for the power re- 
 quired. 
 
 D = j/TT 2 . 
 
 P 
 
 Rule. — Multiply the pressure on the piston of the cylinder by the square of the diameter of the forc- 
 ing pump, and divide the product by the force with which the plunger descends ; then the square root 
 of the quotient will be the diameter of the cylinder sought. 
 
 d= V pD\ 
 
 Rule.- — Multiply the force with which the plunger descends by the square of the diameter of the cylin- 
 der and divide the product by the entire pressure on the piston ; then extract the square root of the 
 quotient for the diameter of the forcing pump. 
 
 The Hydrostatic press is generally furnished with an indicator or safety-valve for measuring the inten- 
 sity of pressure, which maybe easily estimated by considering the diameter of the valve, and the pres- 
 sure upon it as the plunger of the forcing pump, and using previous rules. 
 
 To determine the thickness of metal in the cylinder to withstand the required pressure. — The amount 
 of force which tends to rupture the cylinder along the curved side, that is to divide the cylinder in halves 
 lengthways, is equal to the pressure per square inch on each lineal unit of the diameter multiplied by 
 the length of the cylinder. 
 
 Thus, let the piston of a hydraulic press be 10 inches in diameter, and the pressure 300 tons net ; then 
 the pressure per square inch of piston will be 300 tons divided by the number of square inches in the 
 piston, or 6 iL|jdj.J. 0 = 7.639 lbs. The pressure per inch in length of the cylinder tending to ^plit or tear 
 it apart, is equal to the diameter multiplied by the pressure per square inch, or in this case, 10 x 7639= 
 76,390 lbs., of which, of course, each side sustains one half. 
 
 The cohesive strength of cast iron varies from 13,000 to 20,000 lbs. per square inch ; of wrought 
 iron, from 50 to 60,000 lbs. ; 8,000 lbs. may be taken as the safe limit for cast iron, 20,000 for wrought 
 iron ; hence, to withstand a force equal ’U?-2iL 0 or 38,195 lbs. on each side ; the thickness, if cast iron, 
 should be about 5 inches ; if wrought iron, 2 inches. 
 
 Presses made to withstand but little pressure, that is per square inch, are mostly made with cylinders 
 of cast iron. Some of the cylinders of large presses are made of cast iron, bound with wrought iron 
 hoops, as fig. 2289, but the best material to withstand great pressure, is wrought iron. Of this material 
 R. Hoe & Co., of New York, make their presses, and of this are the jacks of R. Dudgeon constructed. 
 
 An English rule for the construction of cast iron cylinders, is to make the thickness of metal equal 
 to the interior radius of the cylinder, and to determine the entire pressure in tons. When the diameter 
 of the cylinder is given, the following simple rule is used : 
 
 Rule. — Multiply the square of the diameter in inches by the constant number, 2-9186, and the product 
 will be the pressure in tons. 
 
 And again, when the pressure in tons is given, the diameter of the cylinder may be determined by 
 reversing the process, or by the following rule : 
 
 Rule. — Divide the given pressure in tons by the constant number 2-9186, and extract the square root 
 of the quotient for the diameter of the cylinder in inches. 
 
 Example. — The diameter of the cylinder in a hydrostatic press, is 10 inches; what is its power-, or 
 what pressure does it transmit ? 
 
 Here, by the first rule above, we have, P = 10 2 x 2-9186 = 291'86 tons. 
 
 Example. — What is the diameter, and what the thickness of metal, in a press of 300 tons power? 
 
 By the second rule above, we have, D* = 300 -f- 2-9186 = 102-81 nearly; 
 therefore by extracting the square root, we obtain, D = ^ 102-81 = 10-13 inches ; 
 consequently, the thickness of metal is, t— 10 - 13-t-2 = 5-065 inches. 
 
 The hydrostatic press is one of the most convenient and simplest of all machines for transmitting 
 great force ; it is used for punching, pressing, lifting and pulling. It was used for raising the immense 
 tubes of the Conway Tubular Bridge, and is in general use for the baling and pressing of mate- 
 rials and goods. At the United States Navy Yard, Washington, it is used as a proving machine for 
 proving chain cables ; as a jack it is made portable, and is applicable to all the purposes for which 
 such machines are intended. 
 
 Figs. 2280, 2283 represent the front and side elevation of a small hydraulic press with a hand forcing 
 pump : F is a strong metallic cylinder of cast-iron, or some other material of sufficient density to pre- 
 vent the fluid from issuing through its pores, and of sufficient strength to preclude the possibility of 
 rupture, by reason of the immense pressure which it is destined to withstand. 
 
 The cylinder F is bored and polished with the most scrupulous precision, and fitted with the movable 
 piston D, which is rendered perfectly water-tight, by means of leather collars constructed for the purpose, 
 and fixed in the cylinder by a simple but ingenious contrivance to be described hereafter. 
 
 Into the side or base of the cylinder F, the end of a small tube b b b is inserted, and by this tube the 
 
38 
 
 HYDROSTATIC PRESS. 
 
 water is conveyed or forced into the cylinder ; the other end of the tube is attached to the forcing-puinp 
 as represented in Fig. 2280 ; but this will be more particularly explained in another place. 
 
 A A are two very strong upright bars, generally made of wrought-iron, and of any form whatever, 
 corresponding to the notches in the sides of the flat table E, which is fixed upon the end of the piston D, 
 and by workmen is usually denominated the “ follower ” or “ pressing-table .” 
 
 B is the top of the frame into which the upright bars A A are fixed, and c c is the bottom thereof 
 both of which are made of cast, in preference to wrought-iron, being both cheaper and more easily 
 moulded into the intended form. 
 
 The bottom of the frame c c is furnished with four projections or lobes, with circular perforations, for 
 /he purpose of fastening it by iron bolts to the massive blocks of wood, whose transverse sections are 
 indicated by the lighter shades at G G. The top B has two similar perforations, through which are 
 passed the upper extremities of the vertical bars A A, and there made fast, by screwing down the cup- 
 nuts represented at a and a. 
 
 Fig. 2281 represents the plan of the top, or, as it is more frequently termed, the head of the frame; 
 the lower side or surface of which is made perfectly smooth, in order to correspond with, and apply to 
 the upper surface of the pressing-table E, in Fig. 2280 ; this correspondence of surfaces becomes neces- 
 sary on certain occasions such as the copying of prints, taking fac-similes of letters, and the like ; in all 
 such cases, it is manifest, that smooth and coincident surfaces are indispensable for the purpose of ob- 
 mmng true impressions. 
 
 Fig. 2281 represents the upper side of the block, in which the middle part B (through whose 
 rounded extremities a and a, the circular perforations are made for receiving the upright bars or 
 rods A A, Fig. 2280, is considerably thicker than the parts cn ee.ch side of it ; this augmentation of 
 thickness is necessary to resist the immense strain that comes upon it in that part ; for although the 
 pressure may be equally distributed throughout the entire surface, yet it is obvious that the mechani- 
 cal resistance to fracture must principally arise f.-om that part which is subjected to the reaction of the 
 upright bars. 
 
 Fig. 2282 represents the plan of the base or bottom of the frame ; it is generally made of uniform 
 thickness, and of sufficient strength to withstand the pressure ; for be it understood, that all the parts of 
 the machine are subjected to the same quantity of strain, although it is exerted in different ways. The 
 upright bars, cylinders, and connecting-tubes resist by tension, the pistons by compression, and the 
 pressing-table, together with the top and bottom of the frame, resist transversely. 
 
 The circular perforations cc correspond to a a in the top of the frame, and receive the upright bars in 
 the same manner ; the perforations clddd receive the screw-bolts which fix the frame to the beams oi 
 timber represented at G G, Fig. 2280 ; the large perforation F receives the cylinder, the upper extremity 
 of which is furnished with a flanch, for the purpose of fitting the circular swell around the perforation, 
 and preventing it from moving backwards during the operation of the instrument. 
 
 A side view of the engine, as thus completed, is represented in Fig. 2283, where, as is usual in ail 
 such descriptions, the same letters of the alphabet refer to the same parts of the structure. 
 
 F is the cylinder into which the fluid is injected ; D the piston, on whose summit is the pressing-ta- 
 ole E ; A one of the upright rods or bars of malleable iron ; B the head of the press, fixed to the 
 upright bar A by means of the cup-nut a ; c the bottom, in which the upright bar is similarly fixed ; 
 ind G a beam of timber supporting the frame with all its appendages. 
 
 But the hydrostatic press , as here described and constructed, must not be considered as fit for imme- 
 diate action ; for it is manifestly impossible to bore the interior of the cylinder so truly, and to turn the 
 piston with so much precision, as to prevent the escape of water between their surfaces, without in- 
 creasing the friction to such a degree, that it would require a very great force to counterbalance it. 
 
 In order, therefore, to render the piston water-tight, and to prevent as much as possible 
 the increase of friction, recourse must be had to other principles, which we now proceed to 
 explain. 
 
 The piston D is surrounded by a collar of pump leather o o, represented in Fig. 2284, which 
 collar being doubled up, so as in some measure to resemble a lesser cup placed within a 
 greater, it is fitted into a cell made for its reception in the interior of the cylinder ; and when 
 there, the two parts are prevented from coming together by means of the copper ring p p, represented 
 in Fi<>'. 2285, being inserted between the folds, and retained in its place, by a lodgment made for that 
 purpose on the interior of the cylinder. 
 
HYDROSTATIC PRESS. 
 
 39 
 
 The leather collar is kept down by means of a brass or bell-metal ring m m, Fig. 2286, 2286. 
 
 which ring is received into a recess formed round the interior of the cylinder, and the cir- 
 cular aperture is fitted to admit the piston D to pass through it, without materially in- 
 creasing the effects of friction, which ought to be avoided as much as possible. 
 
 The leather is thus confined in a cell, with the edge of the inner fold applied to the 
 piston D, while the edge of the outer fold is in contact with the cylinder all around its 
 interior circumference ; in this situation, the pressure of the water acting between the folds of the 
 leather, forces the edges into close contact with both the cylinder and piston, and renders the w 7 hole 
 water-tight ; for if the leather be properly constructed and rightly fitted into its place, it is almost im- 
 possible that any of the fluid can escape ; for the greater the pressure, the closer will the leather be 
 applied to both the piston and the cylinder. 
 
 The metal ring mm is truly turned in a lathe, and the cavity in which it is placed is formed with the 
 same geometrical accuracy ; but in order to fix it in its cell, it is cut into five pieces by a very fine saw 7 , 
 as represented by the lines in Fig. 2286, which are drawn across the surface of the ring. The four seg- 
 ments which radiate to the centre are put in first, then the segment formed by the parallel kerfs, (the 
 copper ring pp and the leather collar o o being previously introduced,) and lastly, the piston w 7 hich car- 
 ries the pressing-table. 
 
 That part of the cylinder above the ring m m, where the inner surface is not in contact with the pis- 
 ton, is filled with tow, or some other soft material of a similar nature ; the material thus inserted has a 
 twofold use : in the first place, when saturated with sweet oil, it diminishes the friction that necessarily 
 arises, when the piston is forced through the ring m m ; and in the second place, it prevents the admis- 
 sion of any extraneous substance, which might increase the friction or injure the surface of the piston, 
 and otherwise lessen the effects of the machine. 
 
 The packing here alluded to, is confined by a thin metallic annulus, neatly fitted and fixed on the 
 top of the cylinder, the circular orifice being of sufficient diameter to admit of a free and easy motion 
 to the piston. 
 
 If a cylinder thus furnished with its several appendages be placed in the frame, and the whole firmly 
 screwed together and connected with the forcing-pump, as represented in Fig. 2280, the press is com- 
 pleted and ready for immediate use ; but in order to render the construction still more explicit and 
 intelligible, and to show the method of connecting the press to the forcing-pump, 
 let Fig. 2287 represent a section of the cylinder with all its furniture, and a small 
 portion of the tube immediately adjoining, by which the connection is effected. 
 
 Then is F F the cylinder ; D the piston ; the unshaded parts o o the leather collar, 
 in the folds of which is placed the copper ring pp, distinctly seen, but not marked 
 in the figure ; m m is the metal ring by which the leather collar is retained in its 
 place ; n n the thin plate of copper or other metal fitted to the top of the cylinder, SB 
 between which and the plate m m is seen the soft packing of tow, which we have 
 described above, as performing the double capacity of oiling the piston and jjre- 
 venting its derangement. 
 
 The combination at w x represents the method of connecting the injecting-tube to the cylinder: if 
 may be readily understood by inspecting the figure ; but in order to remove all causes of obscurity, it 
 may be explained in the following manner. 
 
 The end of the pipe or tube, which is generally made of copper, has a projecting piece or socket- 
 flanch soldered or screwed upon it, which fits into a perforation in the side or base of the cylinder, 
 according to the fancy of the projector, but in this figure the perforation is in the side. 
 
 The tube thus furnished is forcibly pressed into its seat by a hollow screw vi, called a union screw, 
 which fits into another screw of equal thread made in the cavjty of the cylinder; the joint is made 
 water-tight, by means of a collar of leather, interposed between the end of the tube and the bottom of 
 the cavity. 
 
 A similar mode of connection is employed in fastening the tube to the forcing-pump, the description 
 of which, although it constitutes an important portion of the apparatus, does not properly belong to this 
 place ; the principles of its construction and mode of action must therefore be supposed as known, until 
 we come to treat of the construction and operation of pumps in general. 
 
 Admitting, therefore, that the action of the forcing-pump is understood, it only now remains to explain 
 the nature of its operation in connection with the hydrostatic press, the construction of which we have 
 so copiously exemplified. 
 
 In order to understand the operation of the press, we must conceive the piston D, Fig. 2280, as being 
 at its lowest possible position in the cylinder, and the body or substance to be pressed, placed upon the 
 crown or pressing-table E ; then it is manifest, that if water be forced along the tube b b b by means ot 
 the forcing-pump, it will enter the chamber of the cylinder F immediately beneath the piston D, and 
 cause it to rise a distance proportioned to the quantity of fluid that has been injected, and with a force 
 determinable by the ratio between the square of the diameter of the cylinder and that of the forcing- 
 pump. The piston thus ascending, carries its crown, and consequently, the load along with it, and by 
 repeating the operation, more water is injected, and the piston continues to ascend, till the body comes 
 into contact with the head of the frame B, when the pressure begins ; thus it is manifest, that by con- 
 tinuing the process, the pressure may be carried to any extent at pleasure ; but we have already 
 stated, in developing the theory, that there are limits, beyond which, with a given bore and a given 
 thickness of metal, it would be unsafe to continue the strain. 
 
 When the press has performed its office, and it becomes necessary to relieve the action, the dis- 
 charging-valve, placed in the furniture of the forcing-pump, must be opened, which will admit the water 
 to escape out of the cylinder and return to the cistern, while the table and piston, by means of theii 
 own weight, return to their original position. 
 
 Theory of construction and description of the hydrostatic weighing machine . — If into the side of ac 
 
40 
 
 HYDROSTATIC PRESS. 
 
 open cylindrical or other vessel a bent tube be inserted, and if on the surface of the fluid a movable 
 cover exactly fitting the vessel be placed with a weight upon it, and the tube graduated: — 
 
 Then, any additional weight placed upon the cover, may be determined by knowing the height tc 
 which the fluid rises in the tube ; and conversely : — If the additional weight be known, the height to 
 which the fluid rises in the tube may be found. 
 
 Let A B C D represent a vertical section of a cylindrical vessel, or of any other vessel, whose side? 
 are perpendicular to the horizon ; and let K I C be the corresponding section of the equilibrating tube. 
 
 Let both the vessel and the communicating tube be open at the upper parts A B and 
 d c, and conceive the vessel to be filled with fluid to the line E F or altitude D E ; 
 then, on the surface of the fluid at E F, let there be placed a movable cover exactly 
 fitting the vessel, so that the whole may be water-tight. 
 
 Produce E F to b, then is the point b at the same level in the tube I K, as the surface 
 of the fluid in the vessel whose level is EF: upon the cover EF let the weight w be 
 placed, and suppose a to be the point in the tube, to which the fluid will rise by the 
 action of the cover, together with the weight w which is placed upon it ; in this case, 
 the machine is in a state of equilibrium. 
 
 If some additional weight w' be placed upon the cover, then the original equilibrium 
 will be destroyed, and can only be restored by the fluid ascending in the tube to a sufficient height to 
 balance the additional weight. 
 
 Put D = A B or D C, the diameter of the cylindrical vessel, of which A B C D is a section, 
 d = de, the diameter of the communicating tube K I C, 
 h — b a, the height of the original equilibrating column, 
 w — the weight supported by the column b a , 
 w‘ — the additional weight, whose quantity is required, 
 h' — a K, the increased altitude of the supporting column, 
 
 J = Ei#, the descent of the cover occasioned by the additional load w', and 
 s — the specific gravity of the fluid. 
 
 Then it is manifest, that when the equilibrium originally obtains ; that is, when the surface of the 
 fluid in the tube is at a, and that in the vessel at E F, the pressure of the fluid in the tube exerted at b, is 
 
 p = '7854 d 2 h s, 
 
 where the symbol p denotes the pressure at b ; omitting the steps of the algebraic calculation, we obtain 
 
 w' = 7854 h’ s (D 2 d~). 
 
 If the fluid be water, whose specific gravity is represented by unity, the equation becomes somewhat 
 simpler ; for in that case, we have 
 
 w' = -7854 h' (D 2 + d 2 ). 
 
 From this equation the magnitude of the additional weight, or the measure by which it is expressed, 
 can very easily be ascertained ; and the practical rule by which it is discovered is as follows : 
 
 Rule. — Multiply the sum of the squares of the diameters by '7854 times the rise of the fluid in the 
 tube, or the elevation above the first level, and the product will express the magnitude of the additional 
 weight. 
 
 Example.— The diameter of a cylindrical vessel is 16 inches, and that of the communicating tube one 
 inch ; now, supposing the macliine in the first instance to be in a state of equilibrium, and that by the 
 addition of a certain weight on the movable cover, the water in the tube rises 6 inches above the origi- 
 nal equilibrating level ; how much weight has been added ? 
 
 By proceeding, according to the rule, we have D 2 + d 1 = 16 2 4- l 2 = 256 + 1 = 257, 
 and by multiplication, we obtain w' = '7854 X 6 X 257 = 121P0868 avoirdupois lbs. 
 
 If the additional weight by which the water is made to rise in the tube be given, the distance above 
 the first level to which it will rise, can easily be found ; for let both sides of the equation w' = '7854 h' 
 (D 2 4- i 2 ) be divided by the quantity '7854 (D'- + d 2 ), and we shall obtain 
 
 ■7854 (D 2 + d-j 
 
 And from this equation, we deduce the following rule : — 
 
 Rule . — Divide the additional weight bv the sum of the areas of the movable cover and the cross 
 section of the communicating tube, and the quotient will give the height to which the fluid will rise 
 above the first level. 
 
 Example . — The diameter of the movable cover is 16 inches, and that of the communicating tube one 
 inch ; then, supposing that the machine in the first instance is brought to a state of equilibrium, and 
 that a load of 1211 lbs. is applied on the cover, in addition to that which produces the equipoise; to 
 what height above the first level will the water ascend in the communicating tube ? 
 
 Proceeding, according to the rule, we obtain '7854 (D 2 -f- d") — -7854 (16 2 -f- l 2 ) = 20P8478 divisor; 
 
 2288. 
 
 
 
 
 
 consequently, by division it is 
 
 h' 
 
 1211 
 
 201-8478 
 
 6 inches nearly. 
 
 And exactly after the manner of these two examples, may any other case be calculated ; but in 
 applying the principles to the determination of weights, mercury ought to be employed in preference 
 to water, as it exerts an equal influence in less space, and besides, it is not subject to a change of den- 
 sity by putrefaction and the like. 
 
18 ® 
 
 
 Si pipe leading to small 
 press, Fig. 2290. 
 
 
 WNV'W'WWXtVA^NN 
 
 
 it ft tn 
 
 HYDROSTATIC PRESS. 
 
42 
 
 HYDROSTATIC PRESS. 
 
 Figs. 2280 and 2290 show the elevation and plan of a press capable of giving a pressure equal 
 to 200 tons weight ; also of a press which is suitable for a pressure of 50 tons weight. Bv the arrant 
 ment shown, one set of pumps is sufficient to operate both presses. 
 
 2290 . 
 
 The hand-wheels s and r operate valves which can be opened or shut as is wanted, so as. to connect 
 or shut off either press from the pumps, vi is a hand-wheel moving a valve which allows either of the 
 press cylinders to be drawn off, and returns the water into the tank under the pump through the pipe t 2 . 
 i i s a pipe through which the water is pumped on its passage to the presses until it reaches the valves 
 s and r, where it passes through the pipes r 2 or s 2 to either or both presses, as is wanted. The pumps 
 have three pistons, which are operated by the three-throw crank H, and are driven by means of the 
 pulleys G. . 
 
 ssss are foundation blocks, of stone, on which the presses are placed, m m m m is a wooden frame 
 under the small press to raise it to a convenient height. A and a, are the chambers or cylinders of the 
 presses. B and b , are the pistons. D D and d d, are the top and bottom pieces, and EE.fc, are the 
 columns to the frames. C and c, are the platens or followers which are moved up by the pistons 
 B and b. These presses are from the Lowell Machine Shop. 
 
IIYG ROMETER, 
 
 43 
 
 HYGROMETER, an instrument for measuring the degrees of moisture or dryness of the atmosphere 
 
 Variations in the state of the atmosphere, with respect to moisture and dryness, are manifested by a 
 great variety of phenomena, and, accordingly, numerous contrivances have been proposed for ascertain . 
 ing the amounts of those variations by referring them to some conventional scale. All such contrivances 
 are called hygrometers ; but though the variety of form that may be given to them, or of substances 
 that may be employed, is endless, they may all be referred to two classes ; namely, 1st, those which 
 act on the principle of absorption ; and, 2d, those which act on the principle of condensation. 
 
 1. Hygrometers on the principle of absorption . — Many substances in each of the three kingdoms of 
 nature absorb moisture from the atmosphere with greater or less avidity, and thereby sutt'er some 
 change in their dimensions, or weight, or some of their physical properties. Animal fibre is softened 
 and relaxed, and consequently elongated, by the absorption of moisture. Cords composed of twisted 
 vegetable substances are swollen, and thereby shortened, when penetrated by humidity ; and the 
 alternate expansion and shrinking of most kinds of wood, especially when used in cabinet-work, and 
 after the natural sap has been evaporated, is a phenomenon with which every one is familiar. Many 
 mineral substances absorb moisture rapidly, and thereby obtain an increase of weight. Now it is evident 
 that any of these changes, either of dimension or of weight, may be regarded as the measure of the 
 quantity of moisture absorbed, from which the quantity of water existing in the atmosphere in the state 
 of vapor is inferred ; but many of them are so small in amount, or take place so slowly, that they afford 
 no certain indication of the actual state of the atmosphere at any particular moment. 
 
 Saussure’s hygrometer consists of a human hair, prepared by boiling it in a caustic ley. One ex- 
 tremity of the hair is fastened to a hook, or held by pincers ; the other has a small weight attached to 
 it, by which it is kept stretched. The hair is passed over a grooved wheel or pulley, the axis of which 
 carries an index which moves over a graduated arch. Such is the essential part of the instrument, and 
 it is easy to conceive how it acts. When the surrounding air becomes more humid, the hair absorbs an 
 additional quantity of moisture, and is elongated ; the counterpoise consequently descends, and turns 
 the pulley, whereby the index is moved towards the one hand or the other. On the contrary, when the 
 air becomes drier the hair loses a part of its humidity, and is shortened. The counterpoise is conse- 
 quently drawn up, and the index moves in the opposite direction. The accuracy of the indications 01 
 this instrument depends on the assumed principle that the expansion and contraction of the hair are due 
 to moisture alone, and are not affected by temperature, or other changes in the condition of the atmo- 
 sphere. Experiment shows that the influence of temperature 
 is not very great ; but after all precautions have been taken 
 in preparing the instrument, it is found to be exceedingly 
 irregular in its movements, and subject to great uncertain- 
 ties. Besides, the substance is soon deteriorated, and will 
 scarcely maintain its properties unimpaired during a single 
 year. 
 
 The hygrometer of De Luc consists of a very thin slip of 
 whalebone, cut transversely or across the fibres, and stretch- 
 ed, by means of a spring, between two points. One end is 
 fixed to a bar, while the other acts on the shorter arm of the 
 index of a graduated scale. When the whalebone absorbs 
 moisture it swells, and its length is increased ; as it becomes 
 dry it contracts ; and the space over which the index moves 
 by the one or the other of these effects, gives the measure 
 of the expansion or contraction, and the corresponding 
 change in the hygrometric state of the atmosphere. The 
 action of this hygrometer appears to be more uncertain than 
 that of Saussure. 
 
 The hygrometers which have been proposed on the prin- 
 ciple of a change of weight arising from the absorption of 
 moisture, are liable to still greater objections. Changes of 
 weight may indeed be measured with greater accuracy by 
 the common or torsion balance : but in the present case 
 they are so small, that the particles of dust which are at all 
 times floating in the atmosphere may produce a great alter- 
 ation in the results. 
 
 Hygrometer, portable . — This hygrometer is of very simple 
 construction, and is so arranged as to show the humidity of 
 the atmosphere in decimal parts of the saturation, as well 
 as to afford a means of ascertaining the dew-point. Fig. 
 
 2291 represents a front elevation of the instrument, with the 
 details dotted. A is the back or main supporting piece, 
 of metal or glass, to which is attached, at the lower ex- 
 tremity, a long thin strip of wood, the grain of which runs 
 in a direction transverse to the length of the strip. The 
 upper end of this strip is attached to the axis of the index 
 C, which points out the degrees of saturation of the atmo- 
 sphere. A helical spring D is fastened at its lower end to 
 a bracket projecting from the front of the back piece A, its 
 contrary extremity being fastened, by means of a connecting-cord, to the index axis 0. The action 
 of the spring upon the index is such as to tend constantly to hold it at its original position, while the 
 expansion and contraction of the wood-slip, due to the greater or less amount of moisture hi the atmo- 
 
 2291 . 
 
44 
 
 HYGROMETER. 
 
 iphere, moves the index round accordingly, and thus indicates upon the graduated dial the ratio o 
 moisture existing at the time being. 
 
 The dew-point is readily found by first ascertaining the exact temperature at the time of observation, 
 and from this subtracting the number indicated on the dial by the hand C, the remainder being the 
 temperature corresponding to the amount of moisture in the atmosphere, or, as it is technically termed, 
 the dew-point. 
 
 2. Hygrometers on the principle of condensation . — The instruments of this class are of a more refined 
 nature than those which we have been describing. In order to give an idea of the general principle on 
 which they depend, let us conceive a glass jar, having its sides perfectly clean and transparent, to be 
 filled with water, and placed on a table in a room where the temperature is, for example, 50°, the tem- 
 perature of the water being the same as that of the room. Let us next suppose pieces of ice, or a 
 freezing mixture, to be thrown into the water, whereby the water is gradually cooled down to 55, 50, 
 ‘15, &c., degrees. As the process of cooling goes on, there is a certain instant at which the jar loses its 
 transparency, or becomes dim; and on attentively examining the phenomenon, it is found to be caused 
 by a very fine dew, or deposition of aqueous vapor, on the external surface of the vessel. The precise 
 temperature of the water, and, consequently, of the vessel, at the instant when this deposition begins 
 to be formed, is called the dew-point , and is capable of being noted with great precision. Now this 
 temperature is evidently that to which, if the air were cooled down, under the same pressure, it would 
 be completely saturated with moisture, and ready to deposit dew on any body in the least degree colder 
 than itself. The difference, therefore, between the temperature of the air, and the temperature of the 
 water in the vessel when the dew begins to be formed, will afford an indication of the dryness of the 
 air, or of its remoteness from the state of complete saturation. 
 
 But the observation which has now been described is capable of affording far more interesting and 
 precise results than a mere indication of the comparative dryness or moisture of the atmosphere. With 
 the help of tables of the elastic force of aqueous vapor at different temperatures, it gives the means of 
 determining the absolute weight of the aqueous vapor diffused through any given volume of air, the 
 proportion of vapor existing in that volume to the quantity that would be required to saturate it, and 
 of measuring the force and amount of evaporation. 
 
 The elastic force of aqueous vapor at the boiling point of water is evidently equal to the pressure of 
 the atmosphere. This may be assumed as corresponding to a column of mercury 30 inches in height. 
 Mr. Dalton, in the fifth volume of the Manchester Memoirs, has given the details of a most valuable and 
 beautiful set of experiments, by which he ascertained the elastic force of vapor from water at every 
 degree between its freezing and boiling points, in terms of the column of mercury which it is capable of 
 supporting. As the same experiments have since been frequently repeated, and the different results 
 present all the accordance which can be expected in so delicate an investigation, the tension of vapor 
 at the different temperatures may be regarded as sufficiently well determined. Supposing, then, we 
 have a table exhibiting the elasticity or tension corresponding to every degree of the thermometer, the 
 weight of a given volume of vapor, for example, a cubic foot, may be determined as follows : — 
 
 Steam at 212°, and under a pressure of 30 inches of mercury, is 1100 times lighter than an equal 
 bulk of water at its greatest density, or a temperature of about 40°, and a cubic foot of water at that 
 temperature weighs 437,272 grains ; the weight, therefore, of a cubic foot of steam at that temperature 
 and pressure is, 437272 -j- 1700 = 257'218 grains. Hence we may find the weight of an equal bulk of 
 vapor of the same temperature under any other given pressure, suppose 0'56 of an inch ; for the density 
 being directly as the pressure, we have 30 in. ; 0'56 in. : : 257'218 grs. : 4’801 grs., which is the weight 
 required. 
 
 Having thus explained the principle of the condensation hygrometer, we will now describe one or two 
 of the forms under which it has been most frequently constructed. Daniell’s hygrometer is represented 
 in Fig. 2292 : a and b are two thin glass balls of 1 j inch diameter, connected together by a tube having 
 a bore about J of an inch. The tube is bent at right angles over the two balls, and the arm b c contains 
 a small thermometer d e, whose bulb, which should be of a lengthened 
 form, descends into the ball b. This ball having been about two-thirds 
 filled with ether, is heated over a lamp till the fluid boils, and the vapor 
 issues from the capillary tube f which terminates the ball a. The vapor 
 having espelled the air from both balls, the capillary tube is hermetically 
 closed by the flame of a lamp. The other ball a is now to be covered 
 with a piece of muslin. The. stand y li is of brass, and the transverse 
 socket i is made to hold the glass tube in the manner of a spring, allow- 
 ing it to turn and be taken out with little difficulty. A small thermom- 
 eter kl is inserted into the pillar of the stand. The manner of using the 
 instrument is this : After having driven out all the ether into the ball b 
 by the heat of the hand, it is to be placed at an open window, or out of 
 doors, with the ball b so situated that the surface of the liquid may be 
 on a level with the eye of the observer. A little ether is then to be 
 dropped on the covered ball. Evaporation immediately takes place, 
 which, producing cold upon the ball a, causes a rapid and continuous 
 condensation of the ethereal vapor in the interior of the instrument. The 
 consequent evaporation from the included ether produces a depression 
 of temperature in the ball b, the degree of which is measured by the 
 thermometer d e. This action is almost instantaneous, and the thermom- 
 eter begins to fall in two seconds after the ether has been dropped. A depression of 30 to 40 degrees 
 is easily produced, and the ether is sometimes observed to boil, and the thermr meter to be driven 
 below zero of Fahrenheit’s scale. The artificial cold thus produced causes a condensation of the atmo- 
 spheric vapor upon the ball 6, which first makes its appearance in a thin ring of dew coincident with the 
 
 2202. 
 
ICE. 
 
 4 ; 
 
 Burface of the ether. The degree at which this takes place must be carefully noted. In very damp oi 
 windy weather the ether should be very slowly dropped upon the ball, otherwise the descent of the 
 thermometer will be so rapid as to render it extremely difficult to be certain of the degree. In dry 
 weather, on the contrary, the ball requires to be well wetted more than once, to produce the requisite 
 degree of cold. (Daniel! s Meteorological Essays.) 
 
 The instrument which has now been described is extremely beautiful in principle ; but it may be 
 uoubted whether, even when the greatest caution is observed, the temperature which it indicates is 
 precisely that at which the deposition of dew takes place. The deposition first occurs in a narrow ring 
 on a level with the surface of the ether in the ball b, thereby indicating that the ether is colder at the 
 surface than a little under it. But if the temperature is not uniform throughout the ball, it is evident 
 that only a small part of the bulb of the thermometer can be placed in the point where the greatest 
 cold exists ; consequently, the temperature indicated by the thermometer will be greater than is neces- 
 sary for producing the deposition of moisture : in other words, the dew-point will be given too high. 
 
 HYPERBOLA. A plane figure, formed by cutting a section from a cone by a plane parallel to its 
 axis, or to any plane within the cone which passes through the cone’s vertex. 
 
 The curve of the hyperbola is such, that the difference between the distances of any point in it from 
 two given points is always equal to a given right line. 
 
 If the vertexes of two cones meet each other so that their axes form one continuous straight line, and 
 the plane of the hyperbola cut from one of the cones be continued, it will cut the other cone, and form 
 what is called the opposite hyperbola, equal and similar to the former ; and the distance between the 
 vertexes of the two hyperbolas is called the major axis, or transverse diameter. If the distance between 
 h certain point within the hyperbola, called the focus, and any point in the curve, be subtracted from 
 the distance of said point in the curve from the focus of the opposite hyperbola, the remainder will 
 always be equal to a given quantity, that is, to the major axis ; and the distance of either focus from 
 the centre of the major axis is called the eccentricity, The line passing through the centre perpendicu- 
 lar to the major axis, and having the distance of its extremities from those of this axis equal to the 
 eccentricity, is called the minor axis, or conjugate diameter. An ordinate to the major axis, a double 
 ordinate, and an absciss, mean the same as the corresponding lines in the parabola. 
 
 HYPERBOLIC LOGARITHMS. A system of logarithms, so called because the numbers express 
 the areas between the asymptote and curve of the hyperbola, those areas being limited by ordinates 
 parallel to the other asymptote, and the ordinates decreasing in geometrical progression. But as such 
 areas may be made to denote any system of logarithms whatever, the denomination is not correct. The 
 hyperbolic logarithm of any number is to the common logarithm of the same number in the ratio ol 
 2-30258509 to 1, or as 1 to -43429448. 
 
 ICE. Water in a solid, crystallized state, owing to the abstraction of its combined heat. Its specific 
 gravity, according to Hr. Thomson, is -92. The force of expansion exerted by water in the act of freez- 
 ing has been found irresistible in all mechanical experiments to prevent it. Advantage of this wonder- 
 ful phenomenon is taken to burst bomb-shells, and other massive vessels, by filling them with water, 
 plugging them up, and then exposing them to the frost. Hie effects of this expansive force are often 
 observable by the bursting of trees, and the rending of rocks, attended with a noise resembling the ex- 
 plosion of confined gunpowder. Water, after being long kept boiling, affords an ice more solid, and with 
 fewer air-bubbles, than that which is formed from unboiled water; also pure water, kept for a long time 
 in vacuo, and afterwards frozen there, freezes much sooner than common water exposed to the same 
 degree of cold in the open atmosphere ; and the ice formed of water thus divested of its air, is much 
 more hard, solid, heavy, and transparent, than common ice. Ice, after it is formed, continues to expand 
 by decrease of temperature ; to which fact is probably attributable the occasional splitting and breaking 
 up of the ice of ponds during the time of freezing, and sometimes, independent of other causes, the sep- 
 aration of icebergs from the great frozen continent at the poles. According to Dr. Black, ice requires 
 147 degrees of heat to reduce it to a fluid. 
 
 The thickness of ice required for supporting foot-passengers is about two inches ; for horsemen and 
 light carts, four inches ; and for heavy carriages, not less than six inches : also, if eight inches thick, 
 24-pounder guns on sleighs may pass over it, or any load not causing a greater pressure than 1000 lbs. 
 per square foot on the surface, covered by the runners or skids on which it moves ; and if the ice is 
 weak, they may have balks secured by lashings to the tires of the wheels, for them to slide upon, so as 
 to spread the weight over a larger surface, or lines of planks should be laid down for them to pass over. 
 
 Weak ice may be made capable of bearing even heavy loads in a very short time during frost, by 
 spreading upon it layers of straw or brushwood crossing each other, and sprinkling them with water, 
 so as to form a solid road when frozen ; and if any portion of the river remains unfrozen from the 
 rapidity of the current, it may be made to freeze by mooring trees and brushwood so as to float in it. 
 
 When the ice is too thin for walking upon it, a man may often skate over it, and ice-boats, similar to 
 those used in Canada, might also be used for this purpose. They consist of a slight frame supported 
 on three skates or runners, one of which serves as a rudder ; and, provided with masts and sails, they 
 tack like a ship, with great rapidity, directly to windward, and attain a velocity of twenty miles an 
 hour with a fair wind. 
 
 Floating ice is very liable to destroy bridges; and its effects in rubbing against the piers, when pro 
 pelled by a strong current, are amazing, tearing off the smallest projecting portions, even if of iron. To 
 resist this, ice-breakers in front of the piers are indispensable ; they consist of a frame supported on two 
 rows of piles meeting each other, and forming a small angle against the current : the upper surface 
 should be planked over, and should slope upwards from the water’s edge towards the top of the pier 
 *o that the floating ice may rise over it, and thus break itself up, so as to pass harmlessly between the 
 piers, which, if of piles or trestles, should be carefully planked over, to prevent the ice catching in them. 
 
46 
 
 ICE-HOUSE. 
 
 To cross rivers full of floating ice, very strong boats or canoes, cut out of entire trees, are required tc 
 resist the pressure ; they may be dragged over the floes (even if in motion) which are too solid to admit 
 of breaking canals through them. 
 
 Small barriers of ice, or the keys of barriers interrupting the navigation, or causing an inundation, 
 may be destroyed by turning streams of water against certain points, so as to melt an opening, or by 
 means of charges of powder in casks or bags, fixed underneath or lodged in holes bored in the ice, anc 
 fired simultaneously. A charge of six pounds, placed in the centre of ice two feet thick, will break it 
 up into small pieces throughout a circle of ten feet radius. 
 
 Ice and snow, well rammed together, form temporary parapets capable of even more resistance 
 against shot than those of earth. 
 
 ICE-BOATS. There are many descriptions of boats which come under this denomination ; namely, 
 those that are designed to sail upon the surface of the ice, and those that are employed to ojsen the 
 navigation of frozen rivers or canals, by breaking up the ice. The first mentioned kind of boats is 
 much used in Holland, on the river Maeze and the lake Y. These ice-boats are propelled, it is said, 
 with incredible swiftness, sometimes so quick as to render respiration difficult; they are found very 
 useful in conveying goods and passengers over lakes and great rivers in that country. For this pur 
 pose a boat is fixed transversely over a thick plank, or three-inch deal, under which, at the extremities, 
 are fixed irons, turned up forwards, resembling and operating as skates ; upon this board the boat rests, 
 with its keel at right angles to it; and the extremities of the boards serve as out-riggers to prevent the 
 boat from upsetting, whence, therefore, ropes are fastened that lead to the head of the mast, in the 
 nature of shrouds, and others passed through a block across the bowsprit. The rudder is made some- 
 what like a hatchet, with the edge placed downwards, which, being pressed down, cuts the ice, and 
 serves all the purposes of a rudder in the water, by enabling the helmsman to steer, tack, Ac. 
 
 The other kind of ice-boat alluded to, is a strong and heavy-laden canal boat, fitted up for the pur 
 nose of breaking the ice, by arming the fore-part of the keel and the bows with iron, which penetrate 
 and break down the ice as the boat is drawn forcibly along by an adequate number of horses towing it 
 on the path. This measure of opening the navigation of a canal is seldom adopted, except when the 
 iee is only a few inches in thickness, or when a thaw has rendered thicker ice cf little tenacity. 
 
 ICE-HOUSE. A repository for ice during the summer season. In America and other places ice' is 
 kept in deep cellars, from which the external air is excluded as much as possible, and provided with 
 drains to keep them dry. When the surrounding soil is moist, a frame-work or case of carpentry is 
 constructed, having a grating at bottom, and is so placed in the cellar as to be two or more feet distant 
 from the floor, sides, and roof of the cellar. In this the ice is said to be as perfectly preserved as in a 
 dry cellar. Some market-gardeners preserve ice in great heaps, by merely building it upon an ele- 
 vated base in the open garden, and covering it over and around by a very thick stratum of straw or 
 reeds. This plan of preserving ice is in accordance with Mr. Cobbett’s recommendation in his Cottage 
 Economy , wherein he observes that “ an ice-house should not be underground, nor shaded by trees, but 
 be exposed to the sun and air ;” that its bed should be three feet above the level of the ground, and 
 composed of something that will admit of the drippings flowing instantly off; and he adds, that “with 
 some poles and straw, a Virginian will construct an ice-house for ten dollars, worth a dozen of those 
 which cost the man of taste in England as many scores of pounds.” The ice-houses built by the Vir- 
 ginians consist of an inner shed, surrounded by an outer one, and having a sufficient vacant space 
 between the two to enable a person to walk round ; the walls and roofs of both the sheds are made of 
 thatch, laid on about a foot thick ; and the ice is deposited in the inner shed on a bed of straw. In 
 England and France, the common form of ice-houses is that of an inverted cone, or rather of a hen’s 
 egg, with the broad end uppermost. The situation of an ice-house should be dry, as moisture has a 
 tendency to dissolve the ice ; it should also be so elevated that water may freely run off. It should be 
 exposed to the sun and air, not under the drip, or in the shade of trees, in order that the external de- 
 posit of moisture may be readily evaporated. The form of the building may be varied according to 
 circumstances ; but in the well or receptacle for the ice, it is desirable to have sufficient room for the 
 deposit of two or three years’ consumption, as a provision against mild winters. Where the situation 
 is of a dry, chalky, gravelly, or sandy kind, the pit may be entirely below the surface of the ground ; 
 in which case, an ice-house on the following plan may be advantageously introduced. 
 
 Dig a pit of about twelve feet deep, and wide enough to permit the erection therein of a frame of 
 rough wood posts. This frame is to be fourteen feet wide each way at the bottom, and sixteen feet 
 each way at the top. The posts may be about nine inches in diameter, placed near enough to each 
 other for thin laths to be nailed upon them, and the inside be dressed to an acute angle, so that as little 
 wood as possible may touch the ice. On the inside let thin laths be nailed at about two feet apart. On 
 the outside, at moderate distances, nail rough boards, and fill the place within with wheat or rye straw 
 set on end. The inside of the roof to be made in the same way, and also the gables. Straw is to be 
 sewed on the inside, and heath or straw on the outside of the door. The outside of the roof is to be 
 thickly thatched with straw or heath ; and heath, brushwood, or fir-tops, to be filled in between the 
 outside boarding and the surrounding ground, and then neatly thatched or turfed over. The bottom oi 
 the house, for two feet deep, should be laid with large logs or stones, next with heath, fir-tops, or brush- 
 wood, and then with straw. The ice-house, thus completed, will look like a square beehive inverted, 
 and is then ready to receive the ice or snow. But, unless the house be in a very shady place, it may 
 be necessary to extend the roof, where the door is placed, five or six feet, making a second gable and 
 door, finished in the same way as the first, and fill up the intervening space, except a passage, with 
 heath or straw. 
 
 Mode of filling the house . — When the ice (or snow, if ice cannot be procured,) is put into the house, 
 it must be well beaten down with a pavior’s rammer, or mallet, and the surface always kept concave, 
 as by this means any snow or ice that may melt will run to the middle, or interstices, and freeze. For 
 the same reason, the ice ought always to be kept concave when it is taken out for use. Should the 
 
ICE-SAWS. 
 
 47 
 
 frost be very intense when the ice-house is getting filled, it may be very beneficial at the close cf 
 each day’s felling to throw in thirty or forty pails of water, which will fill the interstices and freeze. 
 When the house is full, spread upon the concave, surface a carpet, or sail split up in the middle, and 
 upon the top thereof a foot thick of water When ice is required for the use of the family, or when it 
 is necessary to put in fresh meat to lie on the face of the ice for preservation, or to take out for use, the 
 straw and carpet, or sail, is to be opened in the middle. Should rats infest the place, an iron-wire 
 frame or case may be required to put the meat or fish, &c., into when lying on the ice. A small open 
 surface-drain ought to be dug round the house, to prevent any water running into it. Opening the door 
 of the house does little harm. Damp or dense substances touching the ice are much more prejudicial 
 than dry air. 
 
 ICE-SAWS. Large saws used for cutting through the ice, for relieving ships when frozen up. The 
 vessels employed in the Greenland fisheries, and others that navigate the polar seas, are regularly fur- 
 nished with these machines, as the lives of the crew not unfrequently depend on the expedition with 
 which a passage can be cut, so as to disengage the vessel before the further accumulation of ice renders 
 it an impossible undertaking. The saw, with a weight suspended to it, is introduced by means of a 
 hole broken through the ice, and is suspended by a rope passed over a pulley fixed to a triangle. A 
 party of a dozen or more men run out and back again with a rope, and thus move the saw up and 
 down till it has cut its way so far as to hang perpendicularly from the pulley. The triangle is then 
 moved a foot or two further, and the sawing recommences, the services of the whole crew being required 
 m this laborious undertaking. 
 
 In Hood’s machine, the saw is suspended by a slight sledge, and is worked by the power of only two 
 or three men at the end of a lever ; a bar, called a propeller, is fixed on the lever between the fulcrum 
 and the saw, the other end resting on the surface of the ice, and so adjusted that each motion of the 
 iever shall produce a cut of a given length, and at the same time, by means of the propeller, push the 
 sledge on, so that the teeth of the saw shall always be in contact with the ice. 
 
 Fig. 2293 gives a side elevation of the machine, aaa is a sledge, of open frame-work, resting on the 
 surface of the ice ; b a transverse bar passing through the lever c c, and forming the fulcrum on which 
 it moves ; this lever has a cross-handle, as represented in perspective in dotted lines ; e a clamp or 
 brace consisting of two cheeks, one on each side of the lever, loosely pinned at top to the lever, and at 
 bottom to the saw /; g a clamp similar to e, by which the weight cl (which is of the shape of a double 
 convex lens) is hung to the lower end of the saw; i the propeller, an iron bar, terminating below in two 
 claws, and at top in a fork, and suspended on the lever by means of a transverse pin k ; l a weight 
 hung to the propeller at m ; n a transverse bar, limiting the motion of the handle-end of the lever in an 
 upward direction. It should be understood that there is a duplicate frame similar to that brought into 
 view, on the other side of the machine, about 18 inches apart, and connected by transverse bars. To 
 prevent the lever from swerving laterally, there are at the handle ends two upright bars, between 
 which the lever moves. The saw, after having once entered the ice, will only require from two to four 
 men to \Vork it ; and it should not be taken out of the ice till after the distance required to be cut 
 through is accomplished. The saw can be guided by the lever in any direction, so as to cut the ice into 
 
48 
 
 ICE-TRADE. 
 
 pieces most convenient for removal, either by pushing them under the adjacent floor of ice, or by drag- 
 ging them out of the ship’s track into clear water. 
 
 ICE-TRADE. The ice-trade of the United States was commenced by Frederic Tudor, of Boston, in 
 1805. The first enterprise resulted in a loss, but was, nevertheless, followed up until the embargo and 
 war put an end to the foreign trade, at which period it had yielded no profit to its projector. After the 
 close of the war, in 1815, Mr. Tudor recommenced his operations by shipments to Havana under a con- 
 tract with the government of Cuba, which enabled him to pursue his undertaking without loss, and 
 extend it, in 1817, to Charleston, S. C. ; in the following year to Savannah, Ga.; and in 1820 to New 
 Orleans. On the 18th May, 1833, the first shipment of ice was made to the East Indies, by Mr. Tudor, 
 and since that period he has extended his operations to Madras and Bombay. 
 
 Previously to 1832 the trade had been chiefly confined to the operations of the original projector, 
 although several enterprises had been undertaken by other persons and abandoned. The increase of 
 shipments to this period had been small, the whole amounting, in 1832, to 4352 tons, which was taken 
 entirely from Fresh Pond, in Cambridge, and shipped by Mr. Tudor, who was then alone in the trade. 
 Up to this time the ice business was of a very complicated nature. Ship-owners objected to receive it 
 on freight, fearing its effect on the durability of their vessels and the safety of voyages ; ice-houses 
 abroad and at home were required, and the proper mode of constructing them was to be ascertained. 
 The best modes of preparing ships to receive cargoes were the subject of expensive and almost endless 
 experiments. The machines to cut and prepare ice for shipping and storing, and to perform the opera- 
 tions of hoisting it into storehouses and lowering it into the holds of vessels, were all to be invented, 
 involving much expense and vexation. Many of these difficulties have now been overcome, and since 
 1832 the trade has increased much, and appears destined to a still more rapid increase for some years. 
 It has also been divided among many parties, and its methods have been further improved and a knowl- 
 edge of them more widely diffused. 
 
 The ice has been chiefly taken from Fresh and Spy Ponds, and since 1841 mainly transported on the 
 Charlestown Branch Railroad, which was constructed for that purpose. Quite recently, ice establish- 
 ments have been made at most of the ponds near Boston, and it is probable that in a few years the 
 product of all these waters may be required to supply the trade. In the year 1839 the great quantity 
 of ice cut at Fresh Pond, and the consequent difficulties which had arisen among the proprietors as to 
 where each should take ice, induced them to agree to distinct boundary lines, which were settled by 
 three commissioners, on the principle of giving to each the same proportion of contiguous surface of the 
 lake, as the length of his shore-line was to its whole border. 
 
 The shipments of ice from Boston coastwise, for the year ending December 31, 1847, amounted to 
 51,887 tons. The ice shipped to foreign ports during the same period amounted to 22,591 tons. 
 
 The freight paid during this year is supposed to have averaged as high as $2.50 per ton, at which 
 rate it would amount, on the 74,478 tons shipped abroad and coastwise, to $186,195 
 
 There is a great variation in the cost of seeming ice and stowing it on board vessels, caused 
 by winters favorable or otherwise for securing it, and by the greater or less expense of the 
 fittings required for voyages of different duration, or by difference of season when the ship- 
 ments are made. Taking all these contingencies into consideration, the cost of ice when stowed 
 on board may be estimated to average $2 per ton, which would give for the quantity shipped. . 148,956 
 
 There were in 1847 upwards of 29 cargoes of provisions, fruits, and vegetables shipped in 
 ice to ports where otherwise such articles could not be sent, the invoiced cost of which, at 
 
 Boston, would average about $2,500 each 72,500 
 
 To these items may be added the profits of the trade to those engaged in it 100,000 
 
 Total returns §507,651 
 
 The methods and materials for preparing vessels for the transportation of ice have been various. 
 Formerly their holds were ceiled up at tire sides, bottom, and top, with boards nailed to joist-ribs se- 
 cured to the side of the vessel, and with double bulkheads forward and aft. The spaces thus formed 
 were filled with refuse tan, rice-hulls, meadow-hay, straw, wood-shavings, or like materials. These 
 spaces were made of a thickness proportionate to the length of the voyage, and with reference to the 
 season. The immediate surface of the ice was covered with the same materials, excepting tan. At 
 the present time sawdust is used almost exclusively for voyages of considerable length. It is placed 
 immediately between the ice and the side of the vessel. This material is obtained from the State of 
 Maine, and before its use for this purpose was entirely wasted at the water-mills, and, falling into the 
 streams, occasioned serious obstructions. During the year 1847, 4600 cords were brought to Boston, at 
 an average value of $2.50 per cord, delivered. 
 
 Almost the whole value of the returns of the ice-trade, including freight, are a gain to this country. 
 The ice itself, the labor expended on it, the materials for its preservation, and the means of its trans- 
 portation, would be worthless if the trade did not exist. 
 
 Ice being shipped and used at all seasons, large storehouses are required to preserve it. Exclusiv 
 of ice-houses on the wharves at Charlestown and East Boston, in which ice is stored for short periods 
 
 there had been erected in 1847, and previously — 
 
 At Fresh Pond, in Cambridge, ice-houses capable of containing 86,732 tons. 
 
 At Spy Pond, in West Cambridge 28,000 
 
 At Little Pond 2,400 “ 
 
 At Wenham Pond 13,000 
 
 At Medford Pond 4,000 “ 
 
 At Eel Pond, in Malden 2,000 “ 
 
 At Horn Pond, in Woburn 4,000 “ 
 
 At Sumner’s Pond 1,200 “ 
 
 Total 141,332 tons. 
 
ICE-TRADE. 
 
 49 
 
 The ice-houses now in use are built above ground. In southern countries, where ice is most valuable, 
 they are constructed at greater expense, usually of brick or stone, and the protection to the ice consists 
 in air-spaces, or in dry, light vegetable substances inclosed between two walls. In this vicinity, on the 
 borders of the lakes, where ice is least valuable, they are usually built of wood, in which case they ar$ 
 of two walls, formed by placing two ranges of joist upright, framed into plates at the top, and placed 
 in the ground at the bottom, or framed into silis ; these two ranges are ceiled with boards secured to 
 that side of each range which is nearest the other, and the space between the two boardings filled with 
 refuse tan, wet from the yards. This wet tan is frozen during the winter, and until it is thawed in the 
 spring and summer, little waste occurs ; afterwards the waste is more rapid ; but, as a large portion oi 
 the ice is shipped or otherwise used before this takes place, the loss in quantity is small, and, occurring 
 before the expenses of transportation have been paid, is of less pecuniary moment. 
 
 In one instance brick has been used in the construction of an ice-house, which covers 36,000 feet of 
 land, and the vaults of this ice-house are 40 feet in depth, and its walls are four feet thick from outside 
 to inside, inclosing two sets of air-spaces. Such a construction is more. costly, but has the advantage of 
 durability and safety from fire, to which ice-houses are much exposed from the frequent juxtaposition 
 of railroad-engines, and the light, dry materials used about them to cover and otherwise preserve ice. 
 
 In the winter of 1847, about 1650 were paid daily for labor of men, and ?230 for that of horses, when 
 the weather was most favorable for cutting ice. Such activity is, however, of short duration, as there 
 are not generally more than 20 days in a season which are really favorable to the operation of securing 
 ice. The price paid is usually §1 per day for horses and men. 
 
 At first the implements of husbandry only were used in securing ice ; but as the trade became more 
 important, other machines and different method's were adopted, and abandoned when better were 
 brought forward, or when the increased magnitude of the business required greater facilities. More ice 
 is now secured in one favorable day than would have supplied the whole trade in 1832. Ordinarily, 
 before there has been cold enough to form ice of suitable thickness, snows fall on its surface. If this 
 occurs when the ice is four or more inches in thickness, and the snow not heavy enough to sink the ice, 
 it can be removed by using horses attached to the “ snow-scraper and under such circumstances this 
 is the method in common use. But if snow falls so heavy as to bring the water above the surface of 
 the ice, it is removed, after it has congealed into snow-ice, with the “ ice-plane.” 
 
 These preliminary expenses are often very great ; frequently, after much expense has been incurred 
 to remove a body of snow or snow-ice, the weather becomes warm, and spoils the ice on which so much 
 has been expended. And, on the other hand, if it is not done, and the cold continues, there will be 
 little or no increase of thickness to the ice, which is equally a disaster. 
 
 When the ice is made up for transportation, it is employed in ships as ballast, for which purpose it is 
 carefully cut up into blocks to fit the hold, and covered with sawdust, straw, and charcoal dust, all non 
 conductors of heat, under cover of which it is conveyed on the voyage. When the ice is regularly 
 shipped as cargo, being cut into blocks, it is packed on board the vessel, in thin air-tight boxes, with 
 straw and hay. In this manner it is conveyed without loss. 
 
 The machinery employed for cutting the ice is worked by men and horses in the following manner : — 
 From the time when the ice first forms, it is carefully kept free from snow until it is thick enough to 
 be cut; that process commences when the ice is a foot thick. A surface of some two acres is then se- 
 lected, which at that thickness will furnish about 2000 tons ; and a straight line is then drawn through 
 its ceutre, from side to side each way. A small hand-plough is pushed along one of these lines, until 
 the groove is about three inches deep and a quarter of an inch in width, when the “ marker,” Fig. 2294, 
 is introduced. This implement is drawn by two horses, and makes two new grooves, parallel with the 
 first, 21 inches apart, the gage remaining in the original groove. The marker is then shifted to the out- 
 side groove, and makes two more. Having drawn these lines over the whole surface in one direction, 
 the same process is repeated in a transverse direction, marking all the ice out into squares of 21 inches. 
 In the mean time, the “ plough,” Fig. 2295, drawn by a single horse, is following in these grooves, cutting 
 the ice to a depth of six inches. 
 
 One entire range of blocks is then cut out with the “ ice-saw,” Fig. 2296, and the remainder are split 
 off towards the opening thus made with an iron bar. This bar, represented in Fig. 2297, is shaped like 
 a spade, and is of a wedge-like form. When it is dropped into the groove, the block splits off ; a very 
 slight blow being sufficient to produce that effect, especially in very cold weather. The labor of “ split- 
 ting” is slight or otherwise, according to the temperature of the atmosphere. “ Platforms,” or low tables 
 of frame-work, are placed near the opening made in the ice, with iron slides extending into the water, 
 and a man stands on each side of this slide armed with an “ice-hook.” With this hook, Fig. 229S, the 
 ice is caught, and by a sudden jerk thrown up the “ slide” on to the “ platform.” In a cold day every 
 thing is speedily covered with ice by the freezing of the water on the platforms, slides, Ac., and the 
 enormous blocks of ice, weighing, some of them, more than 200 pounds, are hurled along these slippery 
 surfaces as if they were without weight. Beside this platform stands a “sled” of the same height, ca- 
 pable of containing about three tons, which, when loaded, is drawn upon the ice to the front of the 
 storehouse, where a large stationary platform, of exactly the same height, is ready to receive its load, 
 whicn, as soon as discharged, is hoisted, block by block, into the house, by horse-power. This process 
 of hoisting is so judiciously managed, that both the taking up of the ice and the throwing it into the 
 
50 
 
 ILLUMINATION. 
 
 building are performed by the horse himself. The frame which receives the block of ice to be hoisted 
 is sunk into a square opening cut in the stationary platform, the block of ice is pushed on to it, the horse 
 starts, and the frame rises with the ice until it reaches the opening in the side of the storehouse ready 
 for its reception, when, by an ingenious piece of mechanism, it discharges itself into the building, and 
 the horse is led back to repeat the process. 
 
 Forty men and twelve horses will cut and stow away 400 tons a day. In favorable weather 100 men 
 are sometimes employed at once. When a thaw or a fall of rain occurs, it entirely unfits the ice for 
 market, by rendering it opaque and porous ; and occasionally snow is immediately followed by rain, 
 and that again by frost, forming snow-ice, which is valueless, and must be removed by the “ plane.” 
 
 The operation of planing is somewhat similar to that of cutting. A plane, Fig. 2299, gaged to run in 
 the grooves made by the marker, and which shaves the ice to the depth of three inches, is drawn by a 
 horse until the whole surface of the ice is planed. The chips thus produced are then scraped off, and if 
 the clear ice is not reached, the process is repeated. If this makes the ice too thin for cutting, it is left 
 in statu quo, and a few nights of hard frost will add below as much as has been taken off above. 
 
 In addition to filling their ice-houses at the lake and in the large towns, the company fill a large 
 number of private ice-houses during the winter — all the ice for these purposes being transported by 
 railway. It will be easily believed that the expense of providing tools, building houses, furnishing 
 labor, and constructing and keeping up the railway, is very great, but the traffic is so extensive, and the 
 management of the trade so good, that the ice can be furnished at a very trifling cost. 
 
 ICOSAHEDRON, or ICOSAEDRON, in geometry, one of the regular platonic bodies, comprehended 
 under twenty equal triangular sides or faces. It is formed of twenty pyramids, whose bases are the 
 twenty equal and equilateral triangles, the summits of which terminate in the centre of the body. 
 
 Let S represent the side ; then will surface = 5 S 2 ■f 3 = 8’66025403 S 2 , and solidity = | S a 
 
 ^ + 5 __ o. 1S16950 g3 
 
 o 
 
 ILLUMINATION. Without entering minutely into the subject, it is evident that the value of any 
 means of illumination must depend upon two things — namely, upon the quantity of light evolved, and 
 upon the consumption of lighting material which accompanies it. A candle, or a lamp, &c., will be the 
 more valuable, the more light it gives from as little tallow or oil as possible. Light cannot be measured 
 with reference to its quantity any more than heat ; it cannot be estimated how much light a flame 
 emits, but it can be scientifically ascertained how much more or less light it evolves, than another flame. 
 
 All determinations of this nature are, therefore, comparative. The most casual observation of two 
 flames, for example, that of a candle and of gas, shows the one, although both are of equal size, to be 
 infinitely brighter than the other. 
 
 .The dissemination of light is entirely effected by radiation; the intensity may, therefore, be said to 
 express the sum of the rays which are emitted to a certain surface, for example, to a square foot. It is 
 evident, that the sum must be diminished by the distance from the source, as the rays separate more 
 and more from each other. According to the laws of optics, the intensity is in relation to the square of 
 the distance ; when, therefore, a surface is illumined to the same extent by two flames, the rays of light 
 from each will be proportional to the square of the distance at which each flame must be placed in 
 order to produce an equal amount of light. It is upon this principle that the actual determination of 
 the intensities and quantities of light depends ; the measure for both is, therefore, the distance to which 
 the flames to be compared must be brought, in order to produce an equal amount of light. (See Pho- 
 tometer, in article Gas.) Practically, however, it is not possible to determine, even approximatively, 
 the degree of brilliancy ; the degree of light is fherefore not observed, but its negation, the shadow. 
 
 In such experiments a board is used, covered with unglazed white paper, before which, at a distance 
 of from two to three inches, an iron rod is placed, which has been previously blackened by holding it 
 in the candle. Opposite this boardj but at the same height, the flames to be compared are so placed 
 that both the shadows (for e^ich throws a shadow) fall close to each other upon the board, and then the 
 stronger flame is so far removed, or the weaker one approached, until both shadows appear equally 
 deep, and lastly, their respective distances from the centres of the flames are measured. The squares 
 of these distances give the relative intensities of light ; if a flame, for example, has been three times as 
 far removed as another, its intensity will be to that of the latter, as 3 2 to l 2 = 9 : 1 = 1 : 9, or 9 times 
 greater. As such observations are simultaneous, and of like duration, they give likewise the relative 
 quantities of light ; for unequal lengths of time, this has only to be multiplied with the respective du- 
 ration. When one of these flames, therefore, burns 3 hours, and the other only 2, then the quantities oi 
 light evolved will be in the proportion, 3 X 9 : 2 X 1 or 27 : 2. 
 
 One circumstance in particular requires notice : that when two perfectly similar shadows of this kind 
 are observed from one side, the one appears brighter than the other, and the same is the case, the order 
 only being reversed, when they are observed from the other side ; so that the rule is, to observe them 
 always from a position exactly opposite the board. Practice is here the best guide in forming rules. 
 
 The usual dimensions of a candle are not fixed arbitrarily or by chance, but are absolutely necessary 
 to a well-regulated process of combustion. If the wick is too large in proportion to the surrounding 
 mass of fat, as is the case in tapers, no reservoir is then formed, and all the advantages attending it are 
 lost. In the opposite case, which applies to all common candles, the wick which is rather too small 
 produces a flame, whilst the outermost layer of fat is beyond the sphere in which fusion is going on. 
 
ILLUMINATION. 
 
 51 
 
 A thin ring-shaped wall, as is easily observed in the less fusible stearine candles, remains erect up to a 
 certain height, and is very objectionable from the shadow which it throws, but more so from its being 
 gradually undermined and falling into th% reservoir, which it overfills and causes the candle to gutter. 
 When it has once overflowed, the evil is doubled, for all the fat which, by overflowing, has formed 
 ridges, is still further removed from the region of the flame. In night lights, made of stearine or wax, 
 where intensity of light is a secondary consideration, this circumstance has been turned to account. 
 These are made with a common-sized wick, but a disproportionate thickness of fat, so that a very deep 
 and full reservoir is formed ; an excess therefore of melted fat, which, as too much of the free part of the 
 wick remains immersed, causes them to give a very small quantity of light. For the sake of safety, 
 they are made so short that they will swim upright upon a basin of water. Several periods must be 
 distinguished in the whole course of the process which is going on in a lighted candle. The heat gen- 
 erated by the flame, and for the greater part carried upwards by the current of air, acts however by 
 radiation to such a degree downwards, that sufficient or rather too much fat is melted, for supplying 
 food to the flame. The fat is supplied directly by the wick, the capillarity of which is constantly at 
 work, sucking up the fluid matter, and carrying it to the sphere of combustion. The lower uncharred 
 portion of the wick (up to d, Fig. 2300) acts the part of a sucking-pump ; the decomposi- 2 3 q 0 
 
 tion takes place in the entire upper black portion : the fat, which arrives there, is im- 
 mediately exposed to a high temperature, without being able to come into direct contact 
 with the air ; it is in the same position as if it were inclosed in an iron retort between red- 
 hot coals, and it suffers, consequently, dry distillation. The gaseous and vaporous com- 
 bustible products form the dark nucleus /of the flame, between which and the surrounding 
 air, the sphere of successive combustion is situated. The air streaming from below up- 
 wards, to the gases in f consumes in the first instance the hydrogen, and separates the 
 carbon as incandescent soot ; this occurs in the luminous part of the flame i. Lastly, on 
 the outside, in the hardly perceptible bluish halo g, the carbon is consumed ; this occurs 
 chiefly at the base, which does not appear luminous, in consequence of the air exerting its 
 full influence at that part. 
 
 Every portion of tallow, which burns and gives out light, prepares the following portion 
 for undergoing the same process. The different states of the flame may be partially made 
 visible by an interesting experiment that is easy of execution. If a bottle is filled with 
 water, and supplied through the cork with a siphon in a downward direction, and a tube 
 drawn out to a point in an upward direction, and this point be brought into the interior of 
 tire flame whilst the water is allowed to run slowly from the siphon, the bottle becomes 
 filled with the combustible vapors in the form of a gray smoke. The vapors obtained from a stearine 
 candle condense, for the most part, to a dry, solid, fatty acid ; not so those from oil or tallow. On blow- 
 ing with the mouth, these vapors may be exp>elled from the bottle, and they burn, when ignited, with a 
 distinct flame, which is but slightly luminous, in consequence of the admixture of ah'. The experiment 
 may be made without danger with a common pipe, and by suction with the mouth. The importance of 
 using hard, solid tallow, to prevent guttering, is obvious, and all the materials should likewise be as 
 pure as possible ; for whatever is not decomposed in the same manner as tallow, or wax, will obstruct 
 the capillary tubes of the wick. 
 
 It is not remarkable from the nature of candles and the mode in which they disseminate light, that 
 their intensity and consequent power of illumination, even under the same circumstances, should be so 
 very variable. In the beginning, when the wick is freshly snuffed, this variation is comparatively slight, 
 and the intensity increases up to a certain point, when, from an excessive length of snuff, deposit of 
 spongy matter, <fec., it constantly diminishes, until the candle is again snuffed or the deposit burnt, and 
 then the process is repeated. Peclet found (by comparison with Carcel’s lamp) that the primary inten- 
 sity of a candle = 100, (6 = 1 lb.,) became in 4 minutes 92, in 8 minutes 50, in 10 minutes 41, in 12 
 minutes 38, in 15 minutes 34, in 20 minutes 32, in 22 minutes 25, in 24 minutes 20, in 28 minutes 19, 
 in 30 minutes 17, and in 40 minutes 14. Another candle, (5 to the lb.,) diminished from its original 
 intensity, = 100, in 5 minutes to 76, in 10 to 55, in 15 to 44, in 20 to 89, in 25 to 32, iu 30 to 30, in 35 
 to 24, and lastly, in 40 minutes to 15. Less than half an hour, therefore, is sufficient to reduce the light 
 from a candle to -I of its original brilliancy. The same diminution was the result of Rumford’s observa- 
 tions, namely, after 29 minutes. When, below, the intensity of candles is compared with Oarcel’s 
 lamp, the mean intensity of 10 minutes’ duration in tallow candles is to be understood, which is about 
 the usual time suffered to elapse between each snuffing ; in stearine, wax, and spermaceti candles, how- 
 ever, the highest intensity is taken, which occurs when the wick, without any deposition of snuff, has 
 begun to emerge from the flame. 
 
 It has already been pointed out, that all determinations of the illuminating power are entirely rela- 
 tive, and hence arises the demand for a suitable point of comparison. 
 
 The flame of Carcel’s clock-work lamp (see Lamps) is of such very uniform brilliancy, remaining un- 
 impaired for several hours after it has been ignited, that lamps, candles, and gas, are very generally 
 compared with it. On comparing two exactly similar lamps of this kind in such a manner, that one 
 was kept constantly burning, whilst the other was freshly ignited for each observation, it was found that 
 the brilliancy which in the beginning was 100, increased in half an hour to 103 ; in one hour to 116, 
 *nd in four hours to 117, which it then retained for four consecutive hours 
 
INCIDENCE. 
 
 d2 
 
 Illuminating Pov:er of Candles. 
 
 Variety of Candle. 
 
 Comparison of 
 the intensity 
 of light. 
 
 • 
 
 Consumption 
 of material in an 
 hour. 
 
 Comparison of illuminating power ! 
 
 Directly. 
 
 With Carcel’s 
 lamp =100. 
 
 [Carcel’s lamp 
 
 Tallow candles, 6s 
 
 “ “ 8 s 
 
 100-00 
 
 10-66 
 
 8-74 
 
 7-50 
 
 13- 61 
 
 14- 40 
 11-40 
 
 42-00 ra P e f ed 
 
 oil. 
 
 8-51 
 
 7'51 
 
 7- 42 
 
 8- 71 
 
 9- 33 
 8-92 
 
 2-318 
 
 1-253 
 
 1-164 
 
 1-011 
 
 1-563 
 
 1-543 
 
 1-614 
 
 100] 
 
 54-04 
 
 50-21 
 
 43-61 
 
 67-41 
 
 66-58 
 
 85’68 
 
 “ “ 5s 
 
 Wax “ 5s 
 
 Stearine “ 5s 
 
 Spermaceti 5s 
 
 Illuminating Power of Lamps. 
 
 Sort of Lamp. 
 
 Breadth of the 
 wick, or diameter 
 of the burner. 
 
 Inner. | Outer. 
 
 Average 
 intensity of 
 light from 
 twelve ex- 
 periments. 
 
 Consump- 
 tion of rape- 
 seed oil in 
 one hour in 
 grammes. 
 
 Quantity of 
 light from 
 an equal 
 quantity of 
 oil, CarcePs 
 lamp =101). 
 
 No. I. Carcel’s clock-work lamp 
 
 Lines. 
 
 68 I 92 
 
 100 
 
 40-64 
 
 100 
 
 ... II. Kitchen lamp 
 
 3-2 
 
 (thick) 
 
 6-65 
 
 8-05 
 
 33-5S 
 
 . . . III. Lamp with flat wick 
 
 8-2 
 
 (broad) 
 
 15-13 
 
 9-40 
 
 65-71 
 
 ... IV. Lamp with chimney 
 
 7 
 
 G 
 
 19-37 
 
 12-33 
 
 63-82 
 
 ... Y. Table lamp with circular oil- vessel, and semi- 
 circular wick 
 
 12 
 
 •5 
 
 32-64 
 
 20-88 
 
 63-54 
 
 ... VI. Astral lamp 
 
 6-2 
 
 9-4 
 
 44-98 
 
 28-70 
 
 63-72 
 
 ... VII. Sinumbra lamp 
 
 5-2 
 
 8-8 
 
 52-50 
 
 26-74 
 
 79-78 
 
 ... VIII. Lamp with flat wick and invert’d reservoir 
 
 8'4 (broad) 
 
 21'50 
 
 14-90 
 
 54-80 
 
 ... IX. Wall lamp with inverted reservoir and semi- 
 circular wick 
 
 13-0 
 
 
 39-33 
 
 2015 
 
 79-35 
 
 ... X. The same with round wick 
 
 7-4 
 
 io-o 
 
 52-54 
 
 29-33 
 
 72-81 
 
 ... XI. Liverpool lamp with inverted reservoir 
 
 60 
 
 9-2 
 
 41-80 
 
 26-78 
 
 63-45 
 
 ... XII. Wall lamp with constant oil level and 
 regulator 
 
 5-8 
 
 8-0 
 
 82-46 
 
 35 44 
 
 111-60 
 
 . . . XIII. Hydrostatic lamp 
 
 7-4 
 
 9-2 
 
 92-44 
 
 38-94 
 
 113-90 
 
 (See Lamps, Light.) 
 
 IMPACT. The single instantaneous blow or stroke communicated from one body, in motion, to an- 
 other, either in motion or at rest. 
 
 IMPENETRABILITY. In physics, one of the essential properties of matter, or body. It is a prop- 
 erty inferred from invariable experience, and resting on this incontrovertible fact, that no two bodies 
 can occupy the same portion of space in the same instant of time. Impenetrability, as respects solid 
 bodies, requires no proof ; it is obvious to the touch. With regard to liquids, the property may be 
 proved by very simple experiments. Let a vessel be filled to the brim with water, and a solid incapa- 
 ble of solution in water be plunged into it ; a portion of the water will overflow exactly equal in bulk 
 to the body immersed. If a cork be rammed hard into the neck of a vial full of water, the vial will 
 burst, while its neck remains entire. The disposition of air to resist penetration may be illustrated in 
 the following way : Let a tall glass vessel be nearly filled with water, on the surface of which a lighted 
 taper is set to float. If over this glass a smaller cylindrical vessel, likewise of glass, be inverted and 
 pressed downwards, the contained air maintaining its place, the internal body of the water will descend, 
 while the rest will rise up at the sides, and the taper will continue to burn for some seconds, encom- 
 passed by the whole mass of liquid. 
 
 IMPETUS. The product of the mass and velocity of a moving body, considered as instantaneous, in 
 distinction from momentum, with reference to time, and force, with reference to capacity of continuing 
 its motion. Impetus, in gunnery, is the altitude through which a heavy body must fall to acquire a 
 velocity equal to that with whicn the ball is discharged from the piece. 
 
 INCIDENCE, in mechanics, is used to denote the direction in which a body, or ray of light, strikes 
 another body, and is otherwise called inclination. In moving bodies their incidence is said to be per- 
 pendicular or oblique, according as their lines of motion make a straight line or an angle, at the point 
 of contact. 
 
 Angle of incidence, generally denotes the angle formed by the line of incidence, and a perpendicular 
 drawn from the point of contact to a plane or surface on which the body or ray impinges. 
 
 Thus if a body impinges on the plane at a point, and a perpendicular be drawn, then the angle made 
 by this perpendicular and the incident ray is generally called the angle of incidence, and the comple- 
 ment of this the angle of inclination. 
 
 When light, or any elastic body, is reflected from a surface, the angle of incidence is equal to the 
 
INDICATORS. 
 
 53 
 
 angle of reflection; and in the case of refraction, the sine of the angle of incidence has to the sine of the 
 angle of refraction a constant ratio. 
 
 INCLINATION, denotes the mutual approach or tendency of two bodies, lines, or planes, towards each 
 other, so that the lines of their direction make at the point of contact an angle of greater or less magnitude. 
 
 INCLINED PLANE. One of the mechanical powers: a plane which forms an angle with the ho- 
 rizon. The force which accelerates the motion of a heavy body on an inclined plane, is to the force of 
 gravity, as the sine of the inclination of the plane to the radius, or as the height of the plane to its 
 length. If/= force accelerating the body on an inclined plane, of which the inclination is i, and if 
 g = force of gravity, f = ff sine i. Hence the motion of a body on an inclined plane, is a motion uni- 
 formly accelerated. 
 
 If two bodies begin to descend from rest, and from the 'same point, the one on an inclined plane and 
 the other falling freely to the ground, their velocities at all equal heights above the surface will be 
 equal. Hence the velocity acquired by a body in falling from rest through a given height is the same, 
 whether it fall freely, or descend on a plane any how inclined. The space through which a body will 
 descend on an inclined plane, is to the space through which it would fall freely in the same time, as the 
 sine of the inclination of the plane to the radius. 
 
 When a power acts on a body, on an inclined plane, so as to keep that body at rest, then the weight, 
 the power, and the pressure on the plane, will be as the length, the height, and the base of the plane, 
 when the power acts parallel to the inclined surface ; that is, 
 
 If the weight be measured by A 0, 
 
 The power will be measured by B 0, 
 
 And the pressure on the plane A B. 
 
 These properties give rise to the following rules : — 
 
 2301. 
 
 weight X height of plane 
 
 power = — ^ 1 
 
 length ot plane 
 
 . , power X length of plane 
 
 weight = c - ^-rr-S— — - 
 
 height ot plane 
 
 , weight X base of plane 
 
 pressure on the plane = — 1 — 
 
 length of plane 
 
 A 
 
 These rules express the conditions of equilibrium, and it is obvious, that if either the weight or the 
 power be increased, (friction excepted,) motion of the body must ensue. 
 
 When the power does not act parallel to the plane, the conditions of 
 equilibrium may be found thus : Draw a line perpendicular to the direction 
 of the power's action ; the weight, power, and pressure on the plane, will 
 be as A C, C B, A B. 
 
 When the line of direction of the power is parallel to the plane, the 
 power is least. 
 
 If two bodies, on two inclined planes, sustain each other by means of a 
 string over a pulley, their weights will be inversely as the lengths of the 
 planes. 
 
 The space which a body descends upon an inclined plane, when descending on the plane by the force 
 of gravity, is to the space which it would fall freely in the same time, as the height is to the length of 
 the plane ; and the spaces being the same, the times will be inversely hi that proportion. 
 
 INDICATORS. The important and useful little instrument which we have represented in the fol- 
 lowing figures has very materially contributed to the perfection and efficiency of our modern steam- 
 engines ; not only by enabling the engineer to ascertain and register the exact values of the forces from 
 which its power is derived, at the point where these forces come into effective operation, but also by 
 pointing out the precise periods, in relation to the different parts of the stroke, at which these elements 
 of power come into action, and thereby conducing to the most economical and perfect combination of 
 them. By its use he is introduced, as it were, into the interior of his engine, and is made cognizant of 
 its most occult and delicate movements. 
 
 The idea embodied in this ingenious and beautiful instrument was originated by the justly celebrated 
 J ames Watt, who, at a very early period in the history of the steam-engine, employed a machine iden- 
 tical in the principle of its operation, though less compact in form than that now so extensively in use. 
 His object was to ascertain with certainty the mean steam pressure, and, more particularly, the propor- 
 tion which the vacuum in the cylinder bore, at different parts of the stroke, to that in the condenser, in 
 order to determine the dimensions of cylinder required for any given power, as also the relative pro- 
 portions proper to be given to the steam and exhaust ports, Ac. Having attained these objects, and 
 given to the world so many imperishable monuments of his genius, succeeding mechanicians seem to 
 have despised the unpretending little instrument by whose assistance he had been led to such splendid 
 results, and, during the space of nearly half a century, to have trusted implicitly, in the construction of 
 (heir engines, either to the absolute accuracy of Watt’s data, or of their own theoretical deductions, in 
 many cases extremely fallacious. From this state of oblivion, the indicator has been, at a comparatively 
 recent period, rescued by the late Mr. Macnaught, of Glasgow, who has greatly improved its construc- 
 tion, and put it into such a compact and portable form as to be easily applicable to steam-engines of 
 every description. Its consequent general adoption has led to some notable improvements, and mate- 
 rially elevated the standard of duty in steam-engines ; it has demonstrated the economy resulting from 
 a liberal use of the expansive power of the steam, and the great advantage attendant upon a more 
 rapid and complete exhaustion than could be attained by the arrangement of slide-valve previously 
 employed. 
 
54 
 
 INDICATORS. 
 
 Macnamght' s Indicators . — The figure comprised under this head represents the form of the indicator 
 as at present constructed by Mr. William Macnaught, being that employed to measure the power ol 
 high-pressure engines, and is also adapted to those hi which steam of a tension not greatly exceeding 
 that of the atmosphere is employed. The two instruments differ in no respect from each other in the 
 principle of then action, and but little in the details of their construction ; accordingly one description 
 will suffice for both, in the course of which we shall notice the points in which each respectively differs 
 from the other. The figures are to a scale of I of an incli to an inch. 
 
 General description . — From a glance at the drawings it will be at once perceived that the indicator 
 is neither more nor less than a small atmospheric steam-engine, with the addition of a spiral spring 
 and graduated scale to mark the degrees of pressure. The steam-cylinder A, Fig. 2303, is of gun- 
 metal, very accurately bored out and fitted with a solid piston a, ground into the cylinder so as to be 
 perfectly steam-tight. A slender steel rod b b is screwed into the piston, and is guided at its upper ex 
 tremity by passing through the cover c of an external brass casing or cylinder B, screwed to the lower 
 end of the steam-cylinder. At this point is also fixed a stop-cock C, destined to form a communication 
 between the cylinder of the steam-engine and that of the indicator ; in the high-pressure indicator this 
 cock is formed with a screw at its lower end, for the purpose of attaching it to the socket-cock, which is 
 permanently fixed to the cylinder cover, while, in the instrument as adapted to low-pressure engines, 
 this attachment is considered to be sufficiently secure by the more convenient method of simply inser* 
 ing the tapered end of the cock C into a corresponding socket accurately ground to fit it. 
 
 .towards the middle of the piston-rod b b a small stud d is fixed immovably by soldering, and to it is 
 screwed a brass disk, having the end of a spiral spring D soldered into it. The opposite extremity ol 
 this spring is secured, in the case of the high-pressure indicator, to the steam-cylinder, and in that 
 used for condensing engines, to the cover of the external casing. This difference in the arrangement 
 of the springs is owing to the difference in the prevailing directions of the motion of the piston a, in 
 either case ; it being considered most expedient to make the springs act by distension, rather than by 
 compression. In the stud is a small square socket, into which, through a slot or opening in the ex- 
 ternal casing B, is inserted a steel piece, part of which is formed into an index or pointer, adapted to 
 work against an adjustable graduated scale, screwed to the outside of the casing B, Fig. 2301. 
 
 Figs. 2305 and 2306 represent plans of 2303 and 2304 respectively. 
 
 The principle on which the strength of the springs is regulated and the scales are graduated is as 
 follows : The area of the piston, the resistance of the spring, and the divisions upon tlie scale, are so 
 proportioned to each other that one pound of pressure in either direction upon the piston will cause the 
 sidex to move through one division upon the scale. In the high-pressure indicator, although the size ol 
 
INDICATORS. 
 
 55 
 
 the piston is invariable, (being uniformly made equal to J of a square inch in area,) the length of the 
 divisions upon the scale is arbitrary, being determined by the amount of steam pressure to which the 
 machine may at any time be subjected, and by the length of scale that can conveniently be applied. 
 The instrument represented in the figures is adapted to indicate up to 60 pounds of pressure, and the 
 scale is equally divided into 20ths of an inch, each of these divisions representing' one pound of pressure 
 upon the square inch of the piston. From these data the spring is to be very carefully constructed, so 
 that 2 ounces (or § of a pound) will move the index through one division of the scale. 
 
 In the low-pressure indicator the process is precisely the same in principle, though somewhat lesc 
 involved. The tension of the steam being low, and the atmospheric pressure limited within 15 pounds 
 to the square inch, the scale is divided into lOths of an inch. The piston is made equal to -J of a square 
 inch in area, and the elasticity of the spring is such that 4 ounces (or \ of a pound) acting upon the 
 piston in either direction, will cause the index to move througli one division of the scale, which, conse- 
 quently, represents one pound of pressure upon the piston of the steam-engine to which this instrument 
 is applied. The zero-point is that at which the index stands when the cock C is shut and the piston a 
 remains undisturbed, and, therefore, when the instrument is in action, it denotes that point in the stroko 
 at which the pressures above and below the piston are balanced. 
 
 From these explanations it will be obvious that, by attaching the instrument to the cylinder of a 
 steam-engine, and observing the motion of the index upon the scale, the maximum steam pressure and 
 vacuum may be at once ascertained. But this is not the only, nor even the most important function of 
 the indicator. It was desirable to find out the exact periods and modes in which these two elements of 
 power come into operation, and especially the mean effective values of each ; the rapidity of the motion 
 through so short a space precluding the possibility of taking these observations with any degree of ac- 
 curacy. These important objects are fully attained by the help of a simple and beautiful contrivance, 
 by which the instrument is made to register its own performances. 
 
 An arm or bracket g is firmly attached to the indicator by being clamped to the external casing B 
 on which it may be set to any convenient elevation, and there secured by a screw. To this bracket is 
 riveted an upright axis, on which, by a long socket, to insure steadiness of motion, is accurately fitted 
 a cylindrical piece F, formed into a pulley at its lower end. The other extremity of the socket carries 
 a small cylindrical box containing a spiral-spring similar to the main-spring of a watch, and attached 
 at one end to the fixed axis, and at the other to the internal surface of the box in which it is inclosed. 
 The bracket g carries also a small friction-pulley j, for the purpose of guiding a cord wrapped round 
 and attached to the pulley F, to any convenient moving part of the engine ; a small catch screwed 
 into the latter, serving to circumscribe its motion to a single revolution. An external cylinder or drum 
 
 E, which may be withdrawn from the instrument at pleasure, is fitted over the revolving cylindrical piece 
 
 F, so as to partake of its motion, and upon it is fixed a slip of brass formed into a double spring 1 1, Fig. 
 2304, for the purpose of securing the slip of paper on which the instrument is to register its performance. 
 This is effected by means of a pencil 
 f placed in a holder e, jointed to the 
 piece of steel on which the index or 
 pointer is formed, and fitted with a 
 small spring, so as to press the point 
 of the pencil gently against the paper 
 cylinder, or admit of its being with- 
 drawn from contact with it at plea- 
 sure. From these arrangements it 
 will be seen that if the piston a be 
 moved up and down, while the pencil 
 is in contact with the cylinder E, a 
 straight line will be traced upon it in 
 the direction of its length ; and if, on 
 the other hand, the cylinder be made 
 to turn upon its axis by pulling the 
 cord, while the piston remains at rest, 
 a straight line will be traced round 
 it at right angles to the former. By 
 the combination of these two motions 
 when the instrument is in operation, 
 a diagram is produced, which repre- 
 sents the performance of the engine 
 at all parts of its stroke. 
 
 Action of the instrument. — The 
 rock C is inserted into the correspond- 
 ing socket prepared for its reception, 
 and the cord which passes under the 
 pulley j is attached to the radius-bar 
 or other moving part of the engine, so 
 as to cause the cylinder E to make 
 one revolution on its axis, coincident 
 with and representing the stroke of the engine ; on the relaxation of the cord at the termination of the 
 up stroke, it is taken up again by the action of the spring in the upright of the cylinder F, and the cylin- 
 der E resumes its original position. The slip of paper is then wrapped tightly round the cylinder, its 
 ends being secured by the pressure of the two springs 1 1. These arrangements made, the pencil f is 
 turned down into contact with the paper, and the engine allowed to make a stroke or two with the cock 
 
56 
 
 INDICATORS. 
 
 C shut, so as to form an atmosphere line. A communication is then opened with the interior of the cyl 
 inu^r of the engine by turning the cock C, and a figure or diagram is traced upon the slip of paper, ex- 
 acUy representing the successive pressures of the steam above, and corresponding degrees of exhaustion 
 below the atmosphere line, at every part of the stroke. To find the mean effective values of each of 
 these pressures respectively, the figure is to be divided, in the direction of its length, into any number 
 
 of equal parts, the perpendicular distances of the outline of the diagram above and below the atmos 
 phere line at each of these points, to be carefully measured upon the scale of the instrument, and th« 
 sum of these to be divided by the number of points taken. Hence the actual power of the engine is 
 easily calculated. 
 
 STorin's Indicator . — That eminent French mechanician, M. Arthur Morin, conceiving, with reason, that 
 considerable inaccuracy was likely to result from the difficulty of constructing the spiral springs in 
 Macnaught’s indicator, so as at all parts of the stroke to denote equal pressures by equal divisions ; 
 and, moreover, considering it desirable to ascertain with greater precision the mean pressures and conse- 
 
INDICATORS. 
 
 57 
 
 quent actual power of engines by taking indications throughout several consecutive strokes, has in- 
 vented a machine by which the former difficulty is obviated, and the latter object is attained. This 
 instrument we have represented in the accompanying figures. 
 
 Fig 2307 is a side elevation, Fig. 2308 an end elevation, and Fig. 2309 a plan of the machine. 
 
 This indicator, like that we have already described, is adapted for being fitted to the cylinder covet 
 of the engine ; it carries a stop-cock pipe G, furnished with two keys ; between these is situated a small 
 horizontal cylinder H, in which a solid piston is accurately fitted to work steam-tight. Towards the 
 middle of the piston-rod m, which is properly guided to a rectilinear course, is a square part in which 
 is inserted the lower end of a long parabolic spring n, the other extremity of which is fixed to the sum- 
 mit of a standard I, forming part of the frame-work of the machine, the spring being so fitted as to 
 admit of a certain amount of travel in the piston in both directions. The square boss of the piston-rod 
 carries also a small pencil o, for the purpose of tracing the different degrees of tension of the steam on 
 the opening of the lower cock G. 
 
 Two pencils pp are placed in holders fixed to the framing exactly opposite to the point at which the 
 pencil o stands when the stop-cock G is shut, and being thus immovable, serve to mark a continuous 
 atmosphere line. A third pencil q, which is susceptible of a slight degree of vertical motion in its socket, 
 and is destined to mark the termination of each stroke, is brought into contact with the paper by placing 
 the instrument so that the working-beam, cross-head, or any other rigid part of the engine may touch 
 lightly at the end of the stroke, the top of an upright rod u, which is connected by a system of levers 
 rst with the top of the pencil q. 
 
 A continuous band or roll of paper may be subjected to the action of this machine for an indefinite 
 period, so as to produce diagrams representing the action of the engine during several successive strokes. 
 The manner in which this is accomplished is as follows : The roll of paper is first wound upon the cyl- 
 inder L, by means of the handle y ; it is then passed over the three small rollers vvv placed to oppose 
 the pressure of the pencils, and is received upon the cylinder M situated at the opposite end of the 
 framing Q Q. The axis of this latter cylinder is produced on one side so as to form also the axis of a 
 conical pulley or fusee N, opposite to which is situated a cylindrical drum O, which receives a uniform 
 motion from any rotating part of the engine to be operated on, by means of a worm-wheel w on its axis, 
 geering with an endless screw on the axis of the strap-pulley P. The cylindrical roller 0 communicates 
 motion to the conical roller 1ST by a cord wrapped round both, and fastened at opposite extremities of 
 each. The object of this arrangement is to compensate for the increased surface velocity due to the 
 increased diameter of the cylinder M as the paper is wound on to it, by imparting to it a proportionally 
 retarded motion. 
 
 This instrument, although highly ingenious in many of its details, and capable of giving very correct 
 indications, is wanting in that portability and compactness which has very materially contributed to 
 bring Macnaught’s instruments into such general use. Moreover, although in any instrument of this 
 nature the observations will be more or less accurate in proportion as the space through which the 
 spring is made to act is more or less limited, yet a considerable advantage results from the length of 
 range in the common indicators. The diagrams being made upon a large scale, the expert engineer is 
 able, at a glance, and without reference to the scale, to ascertain by the mere contour of the figure 
 whether his engine is performing all its functions properly. 
 
 The indicator of the steam-engine appears to fulfil two distinct and very important ends. 
 
 It enables us to discover whether there are any defects in those parts of the machinery by which the 
 steam is admitted to the piston ; for instance, it indicates whether the slides are properly set, or leaky ; 
 whether the stops on the intermediate shaft are properly placed ; whether the steam-ports are large 
 enough ; and, consequently, whether a different arrangement of the working part of the machinery 
 would be advisable. In fact, in the hands of a skilful engineer, the indicator is as the stethoscope of 
 the physician, revealing the secret workings of the inner system, and detecting minute derangements in 
 parts obscurely situated. 
 
 It discovers, at any instant of time, and under any given circumstances, when it may be desirable to 
 apply it, what is the actual power of the engine. 
 
 We will first give a description of the instrument, and then proceed to its various uses. 
 
 Fig. 2310 is an external view of the indicator as constructed. The dotted lines are intended to show 
 the internal parts. A is a hollow cylinder, whose upper end E H is open; the lower end being intended 
 to fit into an orifice in some part of the engine (generally the top or bottom of the cylinder) by means 
 of the screw a ; b is a stop-cock, by which, when the instrument is attached, we can, at will, make or 
 cut off a communication with the internal parts of the engine. Within the hollow cylinder A is a piston 
 in n packed and fitting steam-tight. In practice this piston must not be packed over-tight, for fear of 
 increasing the friction and preventing the free motion of the pencil; but the defect, if any, must be 
 remedied by keeping melted tallow or oil on the upper surface. 
 
 Let us suppose, for perspicuity, the instrument to be in communication with the top of the steam 
 cylinder. Then, when a vacuum is formed above the steam-piston, the atmospheric pressure will force 
 down the piston of the indicator, and it will remain at its lowest position till fresh steam enters ; but it 
 would immediately, (unless prevented,) on receiving a new impulse, be blown out at the open top H E. 
 To prevent this, and at the same time to enable us to measure the force of the steam, a spiral spring 
 presses with its lower extremity against the surface of the piston, while its upper end rests against the 
 fixed cross-piece c. By this arrangement the pressure of the steam will always vary as the place of the 
 piston varies ; for it is a mechanical fact, that the tension of a spring varies as the extension. Hence, 
 the greater the pressure of the steam, the more the spring is compressed ; and, on the contrary, as the 
 steam loses its elastic force, the spring expands and the piston descends. So that, to get a clear idea oi 
 the instrument, conceive the piston to be acted on by opposing forces ; on the lower surface by the 
 pressure of the steam, (continually varying,) and on the upper surface by the pressure of the atmos- 
 phere, (constant,) and by the force of the spring varying so as to balance the steam-pressure Now, as 
 
58 
 
 INDICATORS. 
 
 the steam-force is perpetually varying, it follows that the piston-tube de will be continually rising 01 
 falling. If a pencil be attached to the upper end of this tube d e, iu which the spring works, it will 
 describe a vertical straight line on a piece of paper brought into contact with it. This, however, is not 
 sufficient for our purpose. It would, after it was traced, tell us the maximum and minimum pressure 
 during the stroke ; but the pressure at any particular portion of the stroke would still be undetermined. 
 We must, therefore, have some plan similar to that adopted in other cases where the vertical motion ol 
 a pencil under particular circumstances is to be tegistered. In all such instances, the paper on which 
 the variation is to be laid down is drawn horizontally at a certain rate. If, for instance, we were desirous 
 of recording how the pressure varies with the time, the paper must be drawn uniformly, by connecting 
 it with clock-work, or some other apparatus for giving a uniform motion. But this, however, is not 
 usually the desideratum in the steam-engine. Our object is here to have represented before our eyes 
 the variation of the pressure for every portion of the stroke of the piston ; and this is contrived as fol- 
 
 lows : the paper is wrapped round a cylindrical barrel C, which is brought back against a stop by a 
 strong watch-spring contained in the box E F. A string passes round the pulley D, and is led away 
 through a fair-leader G to some part of the engine having a similar motion to the piston cross-head, only 
 much reduced, by which means the watch-spring and the string are always opposing each other. As 
 the piston rises, the barrel will be pulled from left to right ; and, on the contrary, as the piston descends 
 the string having a tendency to slacken, the barrel will, by the force of the spring, be brought back from 
 right to left. Tire pencil is attached to the upper end of the tube dg , and rising and falling with 
 the indicator piston. It can be brought into contact with the paper on the barrel C or removed from it 
 at will, by means of the joint at g. The rod z, and another one on the opposite side of the cylinder, 
 serve as guides to the piston. 
 
 The paper is kept on the barrel by means of a strip of metal, which also serves another impor- 
 
INDICATORS. 
 
 59 
 
 taut purpose. It will be seen that it is graduated, beginning from zeio, and proceeding upwards and 
 downwards. Now this zero is the level at which the pencil stands when the instrument is unconnected 
 with the steam-engine, and therefore acted on by the atmospheric pressure above and below the piston. 
 The pencil will be seen at this level in the figure. If the barrel be made to revolve under these cir- 
 cumstances, a horizontal line will be traced out. This is called the atmospheric or zero line. And, 
 therefore, the pencil will also be at this level whenever the steam, taking the place of the atmosphere 
 below the piston, exerts the same pressure ; and, consequently, wherever the diagram cuts this hori- 
 zontal line, the pressure of the steam is 15 pounds on the inch;* when on the level of the marks 
 1, 2, 3, <fec., above this zero, the pressure is 16, 17, 18, (fee. ; and when on the level of the marks 1, 2, 3, 
 &c., below this, the pressure is 14, 13, 12, <fec. 
 
 The atmospheric line should not be drawn till after the diagram is taken ; because, as the parts 
 become warm by the steam, slight variations occur in its position, depending principally on the altera- 
 tion in the force of the spring ; and since this line serves as the origin from which the pressures are 
 dated, it is necessary to have it laid down as correctly as possible. 
 
 The small hole in the side of the stop-cock b serves to let the air into the cylinder A when the 
 steam is cut off by the stop-cock, and thus enables us to take the atmospheric line ; it enables the stop- 
 cock to perform the office of a four-way cock ; for by turning it in one direction we allow the steam to 
 enter, and exclude the external air, and by turning it in the opposite direction we admit the air and 
 exclude the steam. 
 
 Having an indicator, a diagram is obtained by looking out for some part of the engine whose motion 
 is proportioned to that of the steam-piston, j- taking care that the space moved through at that part 
 shall be somewhat less than the circumference of the traversing barrel ; that is to say, whatever be the 
 diameter of the traversing barrel, let the movement of the part you are looking for be not greater than 
 three times this diameter. Fasten a string firmly to this point, and have a traversing loop in the loose 
 end of the string ; it must be of such a length that it may be connected with the string passing round 
 the pulley of the indicator. Then close the stop-cock of the indicator, and fix it by the screw a a to 
 some orifice previously prepared in the top or bottom of the cylinder.:]; Insert the pencil you intend to 
 use in the small hole made for its reception, and clamp it there. The pencil should be hard, and have 
 a fine point, to give as clear and distinct a line as possible. Have some pieces of clean writing-paper 
 provided, long enough to be brought round the traversing barrel and overlap about an inch. Wrap a 
 piece smoothly round the barrel, and fix it by means of the clasp containing the scale. Then tear 
 away all the surplus paper, and examine what remains, to see if it be quite smooth ; for if there be any 
 ridges the curve will have an irregular appearance, and might lead us to suppose some of the geer for 
 working the slides had become loose, or much worn. Next wind the indicator string round the pulley 
 of the barrel D, and connect the hook at its extremity with the loop of the string attached to the engine. 
 Adjust the string by means of the running loop, till you are satisfied of the motion of the barrel ; al- 
 lowing it to make nearly a whole revolution, but examining it most carefully to see whether it becomes 
 slack, or overtaut. The stop-cock b may now be opened wide, and the indicator-piston will immediately 
 start into motion ; the piston must be well lubricated, to reduce the friction as much as possible, and at 
 the same time to prevent leakage. Let the instrument work for a few seconds, to allow it to become 
 thoroughly heated ; and when it has arrived at the same temperature as the steam-cylinder, it is in a 
 fit state to trace its diagram. When satisfied of the working of the machine, take hold of the pencil 
 when it comes to the bottom of its stroke, and bring it gently into contact with the paper. This part oi 
 the operation requires some practice ; for if the pencil be allowed to come forward too rapidly, the 
 spring at g, by which it is pressed against the barrel, will break the point; and again, if held too long, 
 the force of the steam, suddenly acting on the machine, will tear it out of the hand, or break the bolder. 
 When left to itself, it will trace out its curve on the paper. As soon as it has made a complete circuit, 
 let the pencil be withdrawn from the paper, (being again careful to take hold of it when at the bottom 
 of its stroke.) In order to have the line distinct, the pencil should not go over the same ground twice. 
 Shut off the stop-cock and the piston will become stationary, both sides being acted on by the pressure 
 of the atmosphere. Bring the pencil again in contact with the paper, and as the barrel traverses, the 
 atmospheric or zero line will be drawn. The operation is now complete, so far as the curve is concerned. 
 Withdraw the pencil once more, unhook the line, and take off the traversing barrel. Next take a fine- 
 pointed hard pencil, and mark off upon the paper the scale of pounds, beginning with the atmospheric 
 line, and proceeding upwards and downwards. After taking the paper from the barrel, it is completed 
 by writing on it the date of the month, the name of the ship, that of the engine, (whether starboard or 
 port,) top or bottom of cylinder, as the case may be, the number of revolutions, the pressure of steam 
 by steam-gage, and of condensation by barometer-gage. 
 
 It is important to have a running loop, or other means of shortening or lengthening the string attached 
 to the indicator. Too much attention cannot be paid to this circumstance. If too much strain be 
 brought upon the string it will stretch, and if the string be too long it will become slack ; and in either 
 case the barrel will be stationary for a small interval while the steam-piston is moving, and the curve 
 will not be a true indication of the motion. 
 
 It is well known that the pressure of the steam and the state of the vacuum on the diagram do not 
 correspond with the boiler-pressure and condenser-vacuum. The truth is, the result will always be less. 
 The difference will depend on the size of the ports, and the work the engine has to do ; the distance 
 
 * More strictly, 14-75 pounds, or a quantity differing from this slightly, according to the state of the weather, 
 t That is to say, when you are wishing to find how the pressure varies with the stroke of the engine. 
 
 X If the top of the cylinder be chosen, the orifice for the grease-cup will generally answer the purpose. In some cases a 
 pipe leads from the top to the bottom of the steam-cylinder, and the indicator is attached to this pipe. It is provided with 
 “top-cocks, so that when once fixed the arrangement is very convenient for taking two diagrams almost simultaneously 
 from the upper and lower part of t® ■ cylinder. The only objection to it seems to consist in the tendency of the steam to 
 condense in the pipe. For this reason it is advisable to have the indicator as close to the cylinder as possible. 
 
30 
 
 INDICATORS. 
 
 the steam lias to travel, the impediments it meets with in its passage from the boiler to the cylinder, 
 and from the cylinder to the condenser. It is evident that the diagram taken from the top of the cyl- 
 inder shows only the pressure and vacuum on the upper surface of the piston, and therefore cannot 
 indicate what is going on below the piston. If our object be merely to calculate the horse-power of the 
 engine, and it be in tolerably good working condition, it is not of much consequence whether the diagram 
 be taken from above or below; but if the actual state of the engine be required, it is necessary to ex- 
 amine into what is passing both above and below the piston, because the errors in one part may have 
 no connection with the errors in another. This will be the case if the slide is too long or too short, so 
 that the upper part may be properly covered, and the lower one disarranged ; or the upper slide may 
 be steam-tight, and the lower one leaky ; and if the indicator be applied to top and bottom, it will de- 
 tect all these inaccuracies, and prevent our attempting to improve the working of one end to the detri- 
 ment of the other. It ought to be remarked here, that in unbalanced engines the diagram from below 
 the piston is generally superior to the other; because, since the steam has more work to accomplish, the 
 piston does not run away from the steam so readily, and, in consequence, the steam-pressure is better 
 maintained ; and there is generally a little more lead to the slide, to allow a freer ingress to the steam. 
 And, therefore, if great accuracy be required, the mean of the top and bottom diagrams should be taken 
 for the horse-power.* * * § 
 
 The string carrying the running loop must not be attached to any part of the engine indiscriminately. 
 Generally speaking, we wish to obtain the pressure of the steam for different portions of the stroke ol 
 the piston ; therefore, the string must be fastened to some part of the engine having a stroke propor- 
 tioned to that of the piston, only much reduced. The part selected must be as near the indicator as 
 other circumstances will permit ; for the greater the distance the longer the string, and consequently 
 the greater is the chance of error from its stretching. Caution must be used also to prevent the string 
 from slipping on the rod to which it is attached. One of the best contrivances for giving a free and 
 proper motion to the string is to fasten a wooden pulley to the radius-shaft , \ to the groove of which the 
 fixed end of the string can be connected. It will be necessary, in most cases, to make use of fair-leaders 
 for the purpose of conveying the motion from the part chosen to the indicator ; and due regard must be 
 paid to this, to ascertain whether the motion of the engine will be fairly represented by the indicator. 
 
 We must bear in mind that all vertical ascending motions are caused by an increasing pressure oi 
 the steam, and that the descent of the pencil is the consequence of the elasticity becoming diminished : 
 and again, that as the traversing barrel revolves from right to left, the piston is descending ; while, on 
 the contrary, as the pencil moves from right to left, the piston is ascending hence we shall arrive at 
 the following general conclusions : — 
 
 1. If the motion of the pencil be vertically upwards, the steam-pressure is increasing, but the piston 
 is not moving. 
 
 2. If the motion be downwards, the steam-pressure is decreasing, but the piston not moving. 
 
 8. If the line traced be horizontal to the right, the steam-pressure does not vary, but the piston is 
 descending.^ 
 
 4. If the line be to the left, the steam-pressure does not vary, but the piston is ascending. 
 
 5. If the line run obliquely to the right upwards, the steam-pressure is increasing, and the piston is 
 descending. \ 
 
 6. If the line run obliquely to the right downwards, the pressure is decreasing, and the piston 
 descending 4 
 
 7. If the line run obliquely to the left downwards, the pressure is decreasing, and the piston 
 ascending .% 
 
 8. If the line run obliquely to the left upwards, the pressure is increasing, and the piston 
 ascending .\ 
 
 Let us refer to the accompanying diagram, Fig. 2312, taken from above the piston of an American 
 steamer, and explain it. 
 
 First, we will put numbers round the diagram, in conformity with the principles laid down in the last 
 paragraph.§ Then, supposing the pencil to commence at A, and trace out the curve in the direction of 
 the arrows, we see that the steam preserves its first and highest pressure for a considerable portion ot 
 the stroke, viz. from A to C ; from C to B the downward stroke continues, but the steam rapidly loses 
 its pressure, although at a variable rate, decreasing rapidly at D. At B the motion of the piston ceases, 
 but the steam continues to fall, till at length the pencil moves back nearly horizontally for some space, 
 showing the pressure to continue invariable, although the piston is rising. At F, however, 8 shows the 
 steam-pressure to increase rapidly and suddenly, the piston still ascending, till, as this oblique line 
 merges into the vertical one at G, we perceive that the piston has arrived at the upper end of its stroke, 
 and the fresh influx of steam drives the pencil up to A. From this point the pencil will retrace the 
 same curve. G D is the atmospheric or zero line. 
 
 When the pencil is at G (or, it may be, rather before arriving at G) the slide is in the position repre- 
 sented at Fig. 2311, and is rising, so that the steam is about to enter the cylinder. Now this will 
 
 * We ought further to remark, that there is a difference between the motion of the slide in the up and down stroke. 
 When the centre of the eccentric has reached that part of its orbit furthest removed from the slide, the motion ol the 
 slide is slowest; and when at that part nearest to the slide, the slide’s motion, though slow, is comparatively quick. But 
 at such times the piston is moving very quick, and, consequently, in the former case the steam-iine is further extended 
 than in the latter. This will therefore help to account for onr getting a better diagram from the top of the cylinder of a 
 beam-engine, and from the bottom of a direct-engine ; and the difference becomes more marked in engines having a short 
 connecting-rod. This is fortunate, for it assists in balancing the engine. 
 
 f In most direct-engines a pin can be fixed on the main centre of the air-pump beam. In Seaward’s direct-engine the 
 string may be attached to the centre-tine of the radius-bar. 
 
 1 This will be the case in one engine, but not necessarily so in another engine; and moreover, if the string be led in 
 another direction the reverse will happen; hut this the practical man can correct fo^himself according to circumstances, 
 and substitute ascending- tor descending, and vice versa. 
 
 § These diagrams should be reversed ; that is to say, the right side should he in place of the left. 
 
INDICATORS. 
 
 61 
 
 take place, as the diagram shows, very slightly before the upward stroke of the piston is accomplished 
 and since the piston and slide are both on the ascent, the lower edge A will have ascended a trifling 
 space when the piston is at its highest. This slight space, though trifling in amount, is important in its 
 results on the working of the engine. It is denominated the had of the slide. As the piston descends 
 the valve rises, and the admitting orifice becomes larger, so that although the piston is gaining speed in 
 its downward course, yet in well-contrived engines the first pressure is continued, as we find in the 
 diagram, through a considerable portion of the stroke. 
 
 The slide, however, has already begun its downward motion, and when the pencil arrives at C it has 
 returned into the position it had in Tig. J. It is clear that as it continues to descend no more steam 
 can be admitted; whatever the cylinder contains will remain pent up; and as the piston continues to 
 move downwards the steam relaxes its force, and we trace a corresponding depression in the diagram 
 from C to D. But a still greater change is to be expected before the piston arrives at its lowest place. 
 Ere that happens the slide will have come into the position shown by Fig. III.; for it is found to be 
 disadvantageous to allow the steam to be kept in the cylinder till the end of the stroke, because the 
 entering steam at the reverse stroke would meet with so much opposition, till the vacuum on the oppo- 
 site side had become tolerably good, that the equability of the motion would be much affected. This 
 being granted, we see that the port will be open for eduction before the end of the stroke, consequently 
 a rapid fall in the curve takes place at D. Moreover, the slide continues to fall, not only after the piston 
 has come to the bottom, but evidently during the greater portion of the up stroke. Although after a 
 very short interval, from the great rate at which the steam rushes into a vacuum, the state of the va- 
 cuum is nearly unaltered, and but little different from that in the condenser ; hence, after turning the 
 right-hand corner, the pencil runs nearly horizontally. At F, however, the slide has returned to the 
 position represented in Fig. III., and is rising ; the piston is also rising, and near the top ; consequently 
 the steam that has not yet made its escape is pent up, and, becoming more and more compressed, the 
 pencil rises rapidly, till, the fresh steam entering, it starts up suddenly to A and retraces the curve. 
 
 The accompanying diagram, Fig. 2313, though being taken from the same engine as that represented 
 in Fig. 2312, differs in many respects. 
 
 We observe, in the first place, that the steam-line I K is shorter 
 than in Fig. 2312, while the exhaust-line LM is longer than in the 
 latter; we infer, therefore, that the steam had a shorter time to come 
 into the cylinder, and a longer time to make its escape. We observe, 
 likewise, that the engine had made a considerable portion of its down- 
 ward stroke before fresh steam was admitted. Now, these phenom- 
 ena can be explained by supposing, from some cause, the slide to be 
 removed bodily below the place it had when the former diagram 
 was traced. For let us refer to the series of representations of the 
 slide before noticed : Thus the point I shows us the steam comes in 
 later in tliis diagram than in the former, and the valve is rising ; consequently its lower edge will oe at 
 some point lower than it would be in ordinary circumstances. Again, the point K of the diagram indi- 
 cates to us that the steam is cut off again sooner, but the slide is descending, and therefore, also, the 
 lower edge is lower than it ought to be. Again, N being too far from the end of the stroke, we see that 
 the exhaust takes place too early ; in other words, the upper edge of the slide is too low. And lastly, 
 the point L (where the cushioning commences) being carried too far to the left, shows us that too great 
 an interval elapses before the upper edge of the slide reaches the upper edge of the port. And, conse- 
 quently, every part of the reasoning proves to us the fact that the slide is lower than should have been 
 the case. Now, in pursuing our inquiries, we shall find this is caused by one of two defects, viz., either 
 the slide-rod is too long, or the eccentric-rod is not of the proper length. But in seeking for the remedy, 
 we must look to the slide-rod alone, because its length can be more easily adjusted than the eccentric- 
 rod, by means of the nuts and screw by which it is fastened to the cross-head. The derangement of 
 the engine, when the diagram represented in Fig. 2313 was taken, was obtained by lengthening the 
 slide-rod fths of an inch. The projection at the point 0 remains to be noticed, although it would never 
 appear except in exaggerated cases, such as the one before us. It will be seen that the cushioning takes 
 place from L to O, and consequently the pencil rises because the steam is compressed ; but the fresh 
 steam does not yet enter, and therefore as the piston descends, this steam, till now compressed, loses its 
 elastic force and the pencil drops, till at o a fresh supply enters and the pencil starts up from o to I, 
 taking a motion compounded of the motion of the piston and the pressure of the steam, for it is to be 
 noticed that the line o I bends sensibly to the left ; this arises from the increasing velocity of the piston, 
 and is not observable in the standard diagram, Fig. 2312, except near the top, because the piston is all 
 but stationary during the short time the steam is entering. 
 
 2313 . 
 
 M L 
 
62 
 
 INDICATORS. 
 
 The opposite effects would have taken place if the slide-rod had been shortened ; that is to say, the 
 upper portion of the diagram would have been spread out, and the lower part contracted. If the whole 
 slide be of the proper length, it is clear that when we get a faulty dia- 
 gram taken from above the piston, the one taken from below it will be 
 similar to Fig. 2314, and vice versa. Hence, therefore, we see one advan- 
 tage of taking both a top and bottom diagram. But if the one diagram 
 be similar to one of those just exhibited, and the other be satisfactory, the 
 fault lies with the slide itself, and cannot be remedied but by the engine- 
 makers. The only plan for the engineer is to divide the fault as equally 
 as he can between the upper and lower parts, by lengthening or shorten- 
 ing the rod, according to circumstances. Moreover, we conceive an engineer should not be satisfied 
 that he has done all, when he has obtained a good diagram from one end of the cylinder ; because, if 
 the fault lay with the slide, he would be improving one to the injury of the other. 
 
 All the motions of the slide, whether up or down, would take place sooner than ordinary, if the stop 
 on the eccentric were too far advanced ; that is to say, the cushioning, the 
 introduction of fresh steam, the cutting off, and the exhaust, would all com- 
 mence sooner. The curve, therefore, instead of being like the standard 
 diagram, will be similar to Fig. 2315, assuming somewhat of a lozenge- 
 shape, the upper right and lower left corners being acute-angled, and the 
 other two obtuse. Again, a little reflection will enable us to discover that 
 similar defects will be exhibited in the lower diagram under these circum- 
 stances, and not opposite defects, as was the case when the slide or eccen- 
 tric rod was at fault. 
 
 This curve was obtained by inserting a piece of metal, half an inch thick, between the stop on the 
 eccentric and that on the shaft. 
 
 It can be readily ascertained, by inspecting the diagram, if the stop on the shaft were not sufficiently 
 advanced ; for in such a case all the motions of the slide will be later than they would be in a well- 
 constructed engine ; consequently, all the upper part of the curve will be drawn towards the right, and 
 all the lower part to the left. And, as in the former case, the same distortion will be observable if a 
 diagram be taken from the lower part of the cylinder. Moreover, if the defect be great, we shall meet 
 with the hump in the lower right-hand corner, similar to that before noticed. 
 
 Fig. 2316 was taken after removing back the stop on the shaft 7-16ths of an inch. 
 
 When the ports of the cylinder or the steam-pipe are too small, the steam will not be able to enter 
 or escape so freely as it ought ; the pressure at first entrance will not be maintained for any length of 
 time, and the vacuum will not be formed rapidly enough, the steam and vacuum lines will therefore 
 lose their horizontality, as is easily discovered in the diagram here given, which was taken from one 
 of our largest engines, afterwards altered by shortening the gab-lever. 
 
 2316. 2317. 2318. 
 
 ^=Y- 
 
 t ] 
 
 When the steam is throttled the upper line of the diagram will rapidly decline, as in Fig. 2317, for 
 the same reason that it would if the steam-pipe or the port were too small, and it will not be so high 
 altogether as in ordinary cases. The vacuum-line, however, will be better than it would otherwise be ; 
 for since the quantity of steam admitted is not so great, the speed of the piston will be reduced. But 
 the exhaust-port is of the same size whether the steam be throttled or not ; and therefore there is more 
 time for the expended steam to rush through this orifice into the condenser, and consequently the 
 vacuum-pressure in the c mdenser and in the cylinder will be more nearly equal, and better in both 
 than when the full power is set on. 
 
 Fig. 2318 represents three diagrams taken from the engine before referred to, the steam being throt- 
 tled to various degrees. 
 
 Fig. 2319 will represent a diagram when the expansive geer alone is used. For let AB represent 
 the whole length of the cylinder, and when the piston has traversed the space A 0, let the ingress of 
 the steam be suddenly stopped. Then, from this epoch, the steam-pressure will decrease, and the pencil 
 begin to descend. Now if the temperature of the.steam be unaltered, the pressure will vary inversely 
 as the space it occupies. Divide, therefore, the space C B into intervals C J G, &c., each equal to 
 A C ; and therefore when the piston is at J, the space A J being twice A C, the pressure of the steam 
 at J is half that at C, at G it will be one-third, at H one-fourth, &c. ; and if lines be drawn through 
 C J G, Arc., parallel to A D, and of the length we have just indicated, making CE = AD, JL = half 
 A D, tfec., and through the upper extremities of these lines a free curve be traced, it will give us an idea 
 of what we ought to expect. But since the slide-valve also acts, we shall have the modification this 
 would produce too, for the slide-valve is placed between the expansion-valve and the cylinder, in most 
 engines ; it follows, therefore, that the effective volume of the steam, intercepted by the expansion- 
 valve, is the whole of the space between it and the piston, and the slide-valve interposes an additional 
 barrier when it begins to cut off the steam. The case, therefore, is somewhat similar to what it would 
 be if there were two expansion-valves, one nearer to the cylinder than the other, and the outer one 
 let ins' first. 
 
 2315. 
 
 2314. 
 
INDICATORS. 
 
 63 
 
 Fig. 2320 represents a series of diagrams taken from tlie same engine. Here 0 gives the full steam 
 without using the expansion-geer, 1 that produced by the first grade of expansion, 2 that produced by 
 the second grade, and so on. We must here remark, that in the interval that elapsed between taking 
 the diagram in Fig. 2317 and the series here represented, the engine had been improved by shortening 
 the gab-lever, and thus enlarging the aperture for steam and eduction. The effect will be observable 
 bv comparing the diagram S with that in Fig. 2317. 
 
 2321. 
 
 We must always rest satisfied that an engine is in good working condition when the general features 
 of the diagram are satisfactory ; for in the hands of an inexperienced person, the indicator may trace 
 an unfaithful representation of the condition of the engine. When the piston is near one end of its 
 stroke, if an undue strain be brought on the string it will stretch, and the indicator-barrel remaining 
 stationary while the steam is entering, the pencil will have a vertical ascending motion, such as is rep- 
 resented in Fig. 2322. On the other hand, if the barrel come back against its stop before the opposite 
 stroke is accomplished, the pencil will fall vertically, as in Fig. 2321. These two figures ought to have 
 been precisely similar, the only cause of difference being the accident of the string. 
 
 The series of steps in the right upper portion of the diagram represented in Fig. 2323 arises from the 
 piston of the indicator being packed over-tight, on which account it descends by a series of jerks as the 
 steam-pressure relaxes. 
 
 2322. 2324. 
 
 The steam-line in Fig. 2324 does not descend so rapidly as in the imaginary curve spoken of in the last 
 page, because the expansion-valve of the engine it was taken from was leaky, and therefore did not en- 
 tirely cut off the steam. 
 
 The most accurate way of ascertaining the power of an engine is by means of the indicator, because 
 the diagram gives the pressure on the piston, and hence, knowing the number of revolutions and the 
 length of stroke, the laboring force can be ascertained. The mean pressure on the piston is obtained 
 as follows : Divide the diagram by a series of equidistant vertical fines, as in Fig. 2325, (the closer the 
 better,) and, taking the horizontal line marked 0 as the origin, draw a series of other lines parallel to it 
 at distances >qual to the intervals corresponding to the scale of pounds on the indicator. This being 
 
 accomplished, if our object be only to form an estimate of the gross power, observe in the middle of 
 each vertical space the number of pounds included between the steam and vacuum lines to tenths, which 
 will be best done by taking the distance with a pair of compasses, and setting it off on the scale of 
 pounds. Write these in their proper columns, as in the figure, along the diagram, and add them to- 
 gether. Then divide the gross result by the number of columns, and we obtain the gross average 
 pressure on the one side of the piston during the up and down stroke. From this it is usual to deduct 
 from 1 pound to 1-5 pounds, according to the size of the engine, for friction, for small engines have more 
 friction in proportion than a larger ; then the result is taken as the effective pressure per square inch, 
 acting uniformly during one whole revolution. Take now the diameter of the cylinder in inches, and 
 square it; then multiply the product by "7854, the result is the number of square inches in the surface 
 of the piston. Multiply this again by the pressure per square inch, as got from the indicator, for the 
 whole pressure in pounds on the surface of the piston. And if this be multiplied by the length of a 
 double stroke, and finally by the number of revolutions, we shall obtain the work done by the engine 
 
14 
 
 INDICATORS. 
 
 It is usual to divide this quantity by 33,000, (supposing this to be the number of pounds a horse would 
 be able to raise one foot a minute, and the quotient is then called the horse-power of the engine. If 
 there be two engines, as is usually the case in steamers, this quantity must be doubled. 
 
 Example . — In the preceding diagram, let the number of revolutions be 38, and therefore the number 
 of single strokes 76. 
 
 Then, since the diameter of steam-cylinder = 20 inches, 
 
 . ' . Diam. 5 = 400 
 •7854 
 
 314‘2000 sq. inches. 
 
 But pressure of steam = 15 '05 lbs. 
 
 Deduction for friction = T50 
 
 . • . Effective pressure per inch = 13'55 
 
 314-2 
 
 2710 
 
 5420 
 
 1355 
 
 4005 
 
 Pressure in lbs. on piston = 4257-410 
 
 76 
 
 2554446 
 
 2980187 
 
 323563-16 
 
 33|000)647|126-62 
 
 19§ horse-power 
 
 If it be necessary to find, separately, the value to be given to the steam and vacuum pressures, we 
 must get the actual pressure, and not the difference of pressure between the steam and vacuum lines. 
 And therefore we might measure the height of the spaces above the atmospheric line, and the depth 
 of the vacuum below it. But, in regard to the steam-line, a difficulty has to be surmounted, which 
 would not be easily got over by practical men unaccustomed to analytical investigations. It is this ; that 
 part of the steam-line is usually above the atmospheric line, and part below it ; and the results of the 
 one must be subtracted from the results of the other. This is more particularly to be noticed in cases 
 where the engine is working expansively, and a great portion of the steam line is in consequence below 
 the atmospheric line. The following suggestion will, however, get over the difficulty : consider the at- 
 mospheric line, as in Fig. 2325, to be 15 lbs. (which is its actual pressure,) and reckoning downwards, call 
 
 »0 
 
 2326. 
 
 10 
 
 in 
 
 17 
 
 111 
 
 15 
 
 14 
 
 13 
 
 12 
 
 11 
 
 10 
 
 6 
 
 5 
 
 4 
 
 3 
 
 2 
 
 1 
 
 0 
 
 the lines below it 14, 13, die., till we come to 3, 2, 1, 0 : the line marked 0 we will assume as that line 
 from which the pressures are measured, and both the steam and vacuum line will be above this new 
 zero line ; and the actual pressures of each will, by these means, be ascertained, and not the relative 
 pressure, as compared with that of the atmosphere. In the preceding diagram, this second method of 
 computation has been performed ; the numbers on the right-hand side beginning from the absolute zero, 
 and the figures along the top and bottom of the curve giving the steam and vacuum pressures respec- 
 tively. The mean of the steam-pressure is 18-85 lbs., and of the vacuum 3'81bs. The difference is 
 15'06, as we obtained before. 
 
 To determine the work done in one single stroke of the piston, we must suppose the piston to be de- 
 scending ; then the steam-pressure acts above the piston, and the vacuum-pressure below the piston ; 
 that is to say, the steam-pressure must be got from the top diagram, and the vacuum-pressure from the 
 bottom diagram ; and we must, therefore, make use of the method proposed in the answer to the last 
 question. Thus, to obtain the mean pressure during the down stroke, take the steam-pressure from the 
 top diagram, and the vacuum-pressure from the bottom diagram, and subtract the latter from the former. 
 Again, to obtain the pressure during the up stroke, take the vacuum - pressure obtained from the top 
 diagram, from the steam-pressure got from the bottom diagram. 
 
 To ascertain by the indicator the quantity of steam an engine uses, we have only to fix on any cod 
 
INDICATORS. 
 
 65 
 
 Tenient part of the steam-line between that point where the steam is cut off and the opening is made to 
 the condenser ; that is to say, between the points C and D in Fig. 2312. Observe, by counting the ver- 
 tical spaces, what proportion the portion of the stroke, as far as this point, bears to the whole length of 
 the stroke. Notice also the pressure of the steam at this point. Then we shall have a certain fraction 
 of the cylinder tilled at each stroke with steam of a given pressure. If now the cubic contents of the 
 cylinder be determined, and the number of times the cylinder is tilled per minute, we shall have the 
 quantity of steam of known pressure supplied to the engine per minute. Thus, suppose that in the 
 engine before alluded to of the cylinder were tilled w 7 ith steam of 15 lbs. pressure ; then, since the 
 number of cubic inches in the cylinder twice filled is 15079-6, the number of revolutions being 34 at the 
 time of experiment, the whole number of inches in a minute = 51252-64, . • . fa X 512526-4 = 461 273-76, 
 and the number of cubic inches of atmospheric steam in an hour = 4C1273'76 X 60 = 27676425-60. 
 But each inch of water is supposed to form 1711 cubic inches of steam at the atmospheric pressure, and 
 
 therefore the number of cubic inches of water evaporated 
 
 27676425-6 
 
 lTLl 
 
 = 16,175 ; and the number of 
 
 gallons (English) of water evaporated 
 
 16175 
 
 277-274 
 
 58 nearly. 
 
 Now, if the theory be correct, this should be the quantity of water evaporated from the boiler, 
 due allowance being made for condensation, Ac., in the steam-pipe and passages. But this is far from 
 being the case, for the number of gallons actually evaporated by the boiler was ascertained to be 108 
 gallons in the hour. We can do nothing more at present than to state the discrepancy, and offer the 
 following hypothesis to account for it. From the violence of the ebullition, the steam is in all likelihood 
 not so dry as that on which careful experiments are made, as is frequently made manifest in boilers 
 that “ prime so that, even in good boilers, it is very possible for the steam to contain much more 
 watery vapor than it would if it were not so rapidly consumed. If so, an inch of water would not under 
 these circumstances form 1711 cubic inches of steam under the atmospheric pressure, and might per- 
 haps form only one-half that quantity, which would be requisite to give the proper number of gallons 
 of evaporated water. It remains to be seen by future experiments whether this be the fact ; and if 
 true, it will throw doubt on the tables of relative volumes of steam and water contained in most works 
 on the steam-engine. 
 
 To determine the friction of the unloaded engine .— If we examine the effect of any machine at work, 
 however simple, we shall find a certain amount of power is requisite to overcome the friction of the 
 engine itself. Divest a common crane of its chain, or any load that may be upon it, and it will still be 
 found that some force must be applied to give motion to the geering itself ; the amount of force de- 
 pending on the materials used, the mode of fitting, and the quantity of geer set in motion. So it is 
 with the steam-engine. A certain amount of power is required to overcome the friction of all its parts ; 
 and in this respect no two engines will be found alike, so much depending on the goodness of the work- 
 manship, and the nice adjustment of the different parts. 
 
 Before proceeding with the method of ascertaining the friction of an engine by the indicator, we would 
 observe, that the greatest care and judgment are requisite in carrying out this experiment ; there are 
 many classes of engines in which the experiment ought not to be tried, especially direct-acting engines. 
 The way, however, to proceed is this ; the communication valve must first be closed, because the engine 
 requires an exceedingly small quantity of steam to work it when the paddle-wheels are disengaged. 
 Then let the blow-valve be opened, to allow any steam that may happen to be in the steam-pipe to 
 escape. In the engine with which we tried our experiments, it was found necessary to destroy the 
 vacuum, befor getting the diagram, by opening the blow-valve, to prevent the engine flying off at too 
 great speed. The throttle-valve must be closed, and the paddles disconnected. After slightly opening 
 the communication and throttle valves, the slide may be opened gradually and cautiously, to admit the 
 steam to the piston, and the injection must be let on as carefully as possible. Work the engine a few 
 strokes by hand, and then let it be thrown into geer, and regulate the working by the throttle and com- 
 munication valves — the object being to give the engine the same number of revolutions without the 
 paddles as it usually has with them — taking care to have the condenser of the same temperature as in 
 the ordinary working state of the engine.* The indicator having been previously fixed and adjusted. 
 
 — 6 
 — 6 
 
 * W e would strongly advise the insertion of the bulb of a thermometer in the condenser of every engine in addition to 
 (he barometer-gage. The bulb must be entirely within the condenser, and the scale (at least that part of it which is 
 above 50° or GO 0 ) outside, in the engine-room. The thermometer chosen for the purpose must be graduated higher than 
 the temperature of the steam in the boiler, otherwise it will burst when the engine is blown through. It must be placed 
 in some part acted on freely by the steam, but free from the splash of the injection water. When the engine is free from 
 air it will then serve as a most delicate test of the vacuum. The temperature preserved should be about 100°. 
 
 Vol. II.— 5 
 
66 
 
 INDICATORS. 
 
 let a diagram be taken : it will be widely different from that when the load is on. Both the steam-line 
 and vacuum-line will be much below the atmospheric line. The diagram may then be taken off, and 
 divided as in the former case. Let the result of this diagram be worked off in the same manner as the 
 common diagram, and the amount is the work the steam lias performed, or in other words, the friction 
 of the unloaded engine. This has been accomplished in the diagram, Fig. 2327. 
 
 This is what is commonly subtracted from the gross result obtained under ordinary circumstances, 
 and denominated friction ; but it is manifest that it is much less than the actual friction of the engine 
 when turning the wheels, for the friction of every machine increases with its load ; and moreover, the 
 injection water, &c., raised by the air-pump increases likewise, and all this goes under the head of fric- 
 tion. The friction of large engines is less in proportion than that of smaller ones ; in large engines it 
 is usual to allow 1 lb. on the square inch of the piston for friction, and in small engines from 1’5 to 2 lbs. ; 
 and in most cases it would be better, except as a matter of experiment, to trust to this than to at- 
 tempt the difficulty of ascertaining it, 
 
 A slide diagram is that in which the indicator-string is connected with the cross-head of the slide, 
 and not with that of the piston ; so that the horizontal motion of the pencil backwards and forwards 
 corresponds to ascents and descents of the slide, and vice versa. And this process will give us many 
 particulars of the slide, without the trouble of taking the engine to pieces for measurement. If the 
 indicator be applied to the upper end of the cylinder, it will give us information of the upper slide-face ; 
 and if to the lower end, of the lower slide-face. As was before stated, the string must be connected 
 with some part having the motion of the slide ; but generally it will be necessary to reduce the motion, 
 because the stroke of the slide is more than the indicator-barrel will allow ; in small engines it may be 
 attached to the cross-head direct. As was before remarked, so long as the pencil is moving from left 
 to right, the slide is rising ; and when moving from right to left, it is falling ; and any rise or fall of the 
 steam-pressure is due to the change of pressure in the steam, as in the common or piston diagram. 
 Then the difference in the two cases would be this : that in the common case we have changes of pres- 
 sure corresponding to motions of the steam-piston ; and in the slide diagram we have changes of pres- 
 sure corresponding to the motions of the slide ; and the important thing to notice is, that every sudden 
 change of pressure refers to some prominent epoch in the slide’s motion ; and consequently we are en- 
 abled to trace successively on the paper, the various positions of the slide from its lowest point as it 
 cushions the steam, allows fresh ingress, &c., and finally arrives at its highest point. 
 
 The following is a slide diagram, obtained by connecting the string to the slide cross-head of our 
 model engine. The whole length of the figure is the same as the travel of the slide. If not, a plan 
 must be adopted to be afterwards explained. When the pencil is at d, the slide is at the lowest point, 
 and the vacuum is very good, as the slide rises till the pencil comes to e ; but since we know d priori , 
 
 2338. 
 
 A 
 
 1! 
 
 
 f 
 
 D 
 
 (1 
 
 E 
 
 J 
 
 /' 
 
 F 
 
 G 
 
 / 
 
 11 
 
 
 
 
 „ 
 
 
 
 IT 
 
 
 
 L 
 
 -i, | 
 
 p 
 
 that the vacuum remains good in the engine till the cushioning commences, therefore when the slide »a3 
 risen from d to c, the cushioning commences ; the cushioning continues as the slide rises till the pencil 
 arrives at f, when fresh steam enters, and after this epoch the slide still rises till the pencil has reached 
 the point h. As the upper line is not so marked in its character as the lower one, we shall not say any 
 thing of the downward stroke. Through the points d cf, &c., draw the vertical lines Ad, Bf, C f D A, 
 cutting the atmospheric line in A B C D, and the horizontal line E H in E F G H. Suppose E H to be 
 the nozzle of the steam-port, on which the face of the steam-slide moves, (the cylinder being for conve- 
 nience of illustration supposed to be lying horizontally ;) then, since when the pencil comes to c, the 
 cushioning commences, F must be the upper edge of the port. Take F J equal to the depth of the 
 port, (which we will suppose known.) Again, since when the pencil is at d the slide is at the lowest, 
 therefore we must suppose it to have started from E ; and consequently, at starting, the upper edge of 
 the slide was below the lower edge of the port, the space J E. When the upper edge of the slide 
 arrives at G, fresh steam enters ; in other words, the lower edge of the port is at J, and therefore the 
 depth of the slide-face is J G. Moreover, since the slide still rises through the space H G, H G will be 
 the greatest amount of opening for steam. The successive positions here spoken of are laid down in 
 the figures under the line EH. F J is the depth of the port. In I the slide is at its lowest; in 1 1 the 
 cushioning is commencing ; in 1 1 1 the steam is about to enter ; in N" the slide is at its highest. 
 
 When the travel of the slide is greater or less than the breadth of the diagram, let GE (Fig. 2329) 
 be the breadth of the diagram, as in the last paragraph ; from G draw G P, making any finite angle 
 with G E, and equal to the travel of the slide. Join P E, and through F and H draw F 0, H R, parallel 
 to E P, and then proceed with the line H P^as in the last paragraph with the line HE, considering 0 
 to be the upper edge of the steam-port, <fcc. 
 
 It should be observed here, that the piston diagram does not necessarily return into itself, and form s 
 
INDICATORS. 
 
 67 
 
 closed figure, as in the preceding diagrams. This only happens because the indicator-barrel contains 
 the spring which, as has been stated, draws back the barrel directly the string relaxes. But we can by 
 a different arrangement produce a figure, of some value, in which the curve proceeds continuously in 
 one direction, and which, therefore, we shall call the “continuous diagram.” Let the spring fitted to 
 the traversing cylinder, for bringing it back, be taken out, and also the stop that prevents the cylinder 
 from going too far ; because our object is to let the barrel revolve freely. The clasp, by which the 
 paper is usually secured, must also be taken off, and the paper must be secured by turning it over the 
 top of the cylinder, and be folded in such a manner that the pressure of the pencil will help to keep it 
 down. Let now some part of the engine be selected where a double pulley may be fitted to revolve, 
 one groove of the pulley having about the same diameter as the pulley attached to the barrel, and the 
 other to the diameter of the paddle-shaft. A string must be passed round this latter pulley and the 
 shaft, and they will revolve in the same time. Another string must be passed round the pulley of the 
 barrel and the smaller of the two pulleys ; and then the indicator-barrel will revolve nearly in the same 
 time as the engine shaft. And if we suppose the shaft to be revolving uniformly, which it will be 
 nearly, especially where there are two engines, the barrel will have a uniform motion in one direction. 
 If the pencil be put to the paper, as in ordinary cases, when the indicator-piston is at the lowest, it will 
 commence tracing its curve. It should be allowed to remain for one entire revolution, and longer if 
 convenient, provided one line do not interfere with the other in going twice over the paper. 
 
 The chief practical utility of these diagrams is, that they serve to show the rate at which the steam- 
 pressure increases or decreases. It will be observed by the continuous diagram, Fig. 2310, that the 
 steam-pressure does not increase instantaneously, as many suppose, and as the common diagram would 
 lead us to believe. The vacuum commences at D and continues to E, the cushioning from E to A ; the 
 fresh steam enters at A, and causes the pencil to rise till it reaches its highest at B. 
 
 If we examine this diagram in page 56 by any of the previous tests, we shall find it rounded 
 off at the corner, a circumstance not easily accounted for. For in all former cases we can only 
 correct a defect in this corner at the expense of the lower corner. As the indicator persisted in 
 giving this outline, and all attempts according to the foregoing principles (by altering the set of the 
 slides, cfcc.) failed, it was at length proposed to examine the steam-piston itself; and accordingly, 
 steam was let in at the lower port, and the cock of the grease-cup opened, when it was discovered that 
 the piston was not steam-tight in the cylinder ; and therefore, although when the engine was working 
 the first impulse of the steam sufficed to drive the pencil up, yet as soon as the piston had got into 
 motion, the escape of steam by leakage did not allow the pencil to rise so rapidly as it otherwise would 
 have done. 
 
 It is evident that no part of the diagram can be below the atmospheric line, when an engine is worked 
 without condensation ; for the pressure can never be less than that of the atmosphere. And since the 
 steam has not a free escape into the air, but is obliged to force open the foot-valve and delivery-valve, 
 and make its way through the air-pump bucket, the resistance it meets with will cause the pressure to 
 be greater than that of the atmosphere. Engines, whose steam-pressure is not considerably greater 
 than that of the atmosphere, cannot be worked on the high-pressure principle. The nest diagram was 
 taken from an engine whose boiler-pressure is I lbs. In 
 high-pressure engines, the diagram will be similar; be- 
 cause the steam having to escape by the blast-pipe, is 
 pent up, and causes the lower part of the diagram to be 
 above the atmospheric line. In general, the steam and 
 vacuum lines must be worked out separately by the plan 
 proposed in page 57 ; for it will be observed, that the lines 
 intersect each other in the diagram. The indicator for high-pressure engines should be made expressly 
 for the purpose • the scale of pounds should have a higher range, but need not go below the atmos- 
 pheric line. 
 
 This curve presents a singular appearance, from the steam and exhaust line intersecting. Since the 
 cushioning begins at the usual place, that is to say, at the same part of the stroke as when used as a 
 low-pressure engine, the steam pent up on the exhaust side, and commencing with a pressure greater 
 than that of the atmosphere, soon surpasses that of the boiler, so that when the port begins to open, 
 the pressure suddenly falls. Again, when the entering steam is cut off, the pressure gradually falls, 
 and before the end of the stroke it is less than that of the eduction ; and when opened again to exhaust, 
 steam enters from the condenser, and the loop of the left-hand corner is formed. 
 
 The Dynamometer, an instrument somewhat similar to the indicator, has been introduced into screw- 
 vessels, for the purpose of enabling the engineer to record the exact amount of pressure given off by 
 screw-shaft, and, consequently, the force the engine, by means of this instrument, is exerting to pro- 
 pel the ship. It is merely a lever, or a combination of levers ; the shaft pressing near the fulcrum, and 
 the farther end of the lever, or combination, being attached to a Salter’s spring-balance. In the dia- 
 gram, Fig. 2310, A B is the screw-shaft pressing as it revolves against a movable pin which is contained 
 in the plomer-block at G, and can slide freely backwards and forwards ; D E is the lever, having the ful- 
 crum at D ; the pin at C presses against a knife-edge on the lever, as is seen in the figure. The rod E F 
 is connected with the spring of a Salter’s balance, which cannot be seen in the figure, but is concealed 
 from sight by the cylindrical barrel IK; F is also attached to the rod G H. This rod, as we perceive, 
 has several grooves in it, so that the small fork carrying the pencil p may be brought in contact with 
 more than one part of the barrel in succession, if desirable. 
 
 The barrel is made to revolve by means of a strap a, b, connecting it with the screw-shaft ; and it will 
 be seen by the figure, that there are pulleys of different sizes connected with the bulk-head at M, and 
 the shaft at N, by which the motion of the cylinder can be regulated, and be made quicker or slower at 
 pleasure. The curve will evidently be somewhat similar to the continuous indicator diagram, consist 
 ing of a series of undulations according to the force of the steam and its action on the propeller. A 
 
68 
 
 INDIGO. 
 
 zero-line must be got, as in the case of the indicator. When the dynamometer is applied to large en 
 gines, the levers can be relieved of the pressure of the shaft; and this being accomplished, the index 01 
 the spring-balance will stand at 0, when the zero-line may be traced. The balance will also give the 
 scale of pounds. After the diagram is traced, draw a series of equidistant lines at right angles to the 
 zero-line, as in Fig. 2310, in the article on the indicator, which represents a dynamometer diagram taken 
 on board a man-of-war steam-vessel, the dimensions being reduced one-half. The distance between the 
 curve and zero-line must be measured and compared with the scale of pounds on the balance. Let 
 this be registered on the diagram in its proper space. The sum of all these is then to be taken, apd 
 divided by the number of spaces taken into account. Thus we shall obtain the mean force of the lever 
 on the spring of the balance ; let this be multiplied again by the leverage of the dynamometer, and the 
 result will be the pressure of the screw-shaft on the dynamometer, and, therefore, on the vessel.* To 
 obtain the leverage, if the lever be compound, multiply together all the long arms, (measuring from the 
 fulcrum,) and divide the product by all the short arms multiplied together, (measuring also from the 
 fulcrum.) 
 
 The horse power of an engine is to be found by the dynamometer in the following manner : 
 
 Having found the number of pounds pressure exerted by the screw-shaft, multiply it by the speed 
 of the ship in knots, and the product by 6080, (the number of feet in a knot;) then divide the result by 
 60, (the number of minutes in an hour,) and by 33,000, and the quotient will be the horse-power. 
 
 Or the work may be shortened, thus : 
 
 Multiply the number of pounds pressure by the speed of the ship, as before, and this product by 
 •00307, and the product gives the horse-power. 
 
 This, it will be observed, is the effective horse-power after making allowance for friction and loss by 
 useless resistance. 
 
 The diagram before referred to will elucidate the process of working out the result. This was taken 
 simultaneously with two others ; and the mean of the three pressures was 4P309 lbs. Multiplying 
 by the power of the system of levers, the result was 80864 pounds, (the pressure exerted by the 
 screw-shaft.) 
 
 The speed of the ship was 9 893 knots. 
 
 Hence 80864 X 9-893 = 79998-7. 
 
 And 79998- X -00307 = 245 nearly, the horse power required. 
 
 The horse-power by indicator at the same time was 465’6, showing a loss of 220-6 by friction, re- 
 sistance, ifec. 
 
 INDIGO. A blue substance much used as a dye-stuff. The best indigo is obtained from an Asiatic 
 and American plant, the Indigofcra. The plant is bruised and fermented in vats of water, during which 
 it deposits indigo in the form of a blue powder, which is collected and dried, so as to form the cubic 
 cakes in which it usually occurs in commerce. Indigo is quite insoluble in water; when heated it 
 yields a purple vapor, which condenses in the form of deep blue or purple acicular crystals. When in- 
 digo is exposed to the action of certain deoxidizing agents, it becomes soluble in alkaline solutions, losing 
 its blue color and forming a green solution, from which it is precipitated by the acids white ; but it in- 
 stantly becomes blue by exposure to air. This white indigo has been termed indigogene, and indigo 
 appears to be its oxide. It is best obtained by mixing 3 parts of finely powdered and pure indigo with 
 4 of green vitriol, 5 of slaked quicklime, and 100 of water, repeatedly shaking the mixture. In about 
 twenty-four hours the supernatant liquor, which is transparent, and of a green color, is to be decanted 
 off, and poured into dilute muriatic acid, when the deoxidized indigo is thrown down ; but, in order to 
 prevent its absorbing oxygen and becoming blue, it must be most carefully excluded from the contact 
 of air, which may be effected by siphoning it off into the acid, collecting it in vessels filled with hydro- 
 gen, and washing it with water deprived of air and holding in solution a little sulphate of ammonia. In 
 this white state indigogene absorbs between 11 and 12 per cent, of oxygen to become blue indigo. It 
 would appear from Dumas’ experiments that indigogene is a compound of 
 
 Atoms. Equivalents. 
 
 Carbon 45 = 270 
 
 Hydrogen 15 — 15 
 
 Nitrogen 3 = 42 
 
 Oxygen 4—32 
 
 1 o 59 
 
 and that indigo consists of 1 atom of indigogene = 359, and 2 of oxygen = 16. The chemical equiva- 
 lent of indigo, therefore, is 375. 
 
 When indigo is dissolved in concentrated sulphuric acid, it forms a deep blue liquid, known to the 
 dyers by the name of Saxon blue. The great mart for indigo is Bengal, and the other provinces subject 
 to the presidency of that name, from the 20th to the 30th deg. of N. lat. ; but it is also cultivated, 
 though not nearly to the same extent, in the province of Tinnevelly, under the Madras government in 
 Java ; in Lueonia, the chief of the Philippine Islands ; and in Guatimala and the Caracas, in Central 
 America. The following remarks, from the Commercial Dictionary, will exhibit the history of this now 
 indispensable commodity, and the difficulties with which it had to contend before it obtained a perma- 
 nent footing in the commerce of Europe. “ It appears pretty certain that the culture of the indigo 
 plant, and the preparation of the drug, have been practised in India from a very remote epoch. It has 
 been questioned, indeed, whether the indicum mentioned by Pliny was indigo ; but, as it would seem, 
 
 * A doubt lias been expressed by some as to whether this is really the force exerted by the shaft on the vessel, on 
 account of the shaft acting on a lever that yields to its force ; but independently of the fact that none of the thrust can 
 he lost, it is clear that the thrust at C is equal to the thrust at D and that at E, and thess are the two forces acting on the 
 vessel. 
 
IRON. 
 
 63 
 
 without any good reason. Pliny states that it was brought from India ; that when diluted it produced 
 an admirable mixture of blue and purple colors, (in diluendo misturam purpuree cceruleique mira.bilen. 
 reddil ;) and he gives tests by which the genuine drug might be discriminated with sufficient precision. 
 It is true that Pliny is egregiously mistaken as to the mode in which the drug was produced ; but there 
 are many examples in modern as well as ancient times to prove that the possession of an article brought 
 from a distance implies no accurate knowledge of its nature, or of the processes followed in its manu- 
 facture. Beckmann (Hist, of Inventions, vol. iv., art. ‘ Indigo’) and Dr. Bancroft (Permanent Colors, 
 vol. i., p. 241-252) have each investigated this subject with great learning and sagacity, and agree in 
 the conclusion that the indicum of Pliny was real indigo, and not, as has been supposed, a drug pre- 
 pared from the isatis or woad. At all events, there can be no question that indigo was imported into 
 modern Europe, by way of Alexandria, previously to the discovery of the route to India by the Cape 
 of Good Hope. When first introduced, it was customary to mix a little of it with woad to heighten anti 
 improve the color of the latter ; but, by degrees, the quantity of indigo was increased ; and woad was, 
 at last, entirely superseded. It is worth while, however, to remark, that indigo did not make its way 
 into general use without encountering much opposition.” 
 
 In common painting indigo is seldom or never used without a small mixture of white. A preparation 
 from the leaves of the anillo is sometimes fraudulently substituted for indigo, but may be at once de- 
 tected by throwing a piece into the fire, as genuine indigo will not burn. 
 
 INERTIA. (See Force.) 
 
 INVOLUTE CURVE, is that which is traced out by the end of a thread (while being unwound) that 
 is coiled round another curve. This species of curve is frequently used in the formation of the teeth ot 
 wheels. (See Geering.) 
 
 IRON, (Sanscr. ais ; Mod. Hindost. lohah ; Mod. Pers. auhun ; Chald. perzela ; Heb. barzcl ; Gr. 
 s ideron ; Swed .je.ru; Dan .jern; Icel .jam; Franco-theot. isar, isarn ; M*so-Goth. ais ; Germ, eisen ; 
 Ang. Sa x. isen, isern, iren ; Low Germ, isen; Fries, ixsen ; Dutch, yzer ; Erse, jarann ; Welch, haiarn ; 
 Lat. ferrum ; Ital. ferro ; Sp. hierro ; Fr. fer, &c.,) one of the longest known, the most generally used, 
 and most extensively applicable of all the metals. Although found native, as it is called, it nowhere 
 exists perfectly pure in nature. In the arts, it occurs under four conditions; 1. as pure iron: 2. crude, 
 or cast iron ; 3. malleable, or wrought, or bar iron ; and 4. steel. Its precipitate, or release from a chem- 
 ical solution or combination, is always pulverulent, and does not present the most important practical 
 characteristics of the metal. Deposited in the electrotype- way, it is more coherent, but still friable. It 
 is difficult to be produced by this method in large plates : pieces of an inch square are rare. Seen by 
 reflected light, its surfaces in this condition are more brown than gray, owing to its immediate oxidation. 
 A fresh fracture is, however, clear gray. Its texture is crystalline, 6r, more properly, an assemblage 
 of crystals loosely cohering, which appear cubic. In this state it is not at all malleable. When fresh it 
 is highly magnetic; but this property rapidly diminishes on exposure to the air or moisture. Its den- 
 sity is not known, and can with difficulty be accurately ascertained. When broken into spiculae and 
 approached to a wire no longer at a red-heat, or even to the lateral flame of a spirit-lamp, it decrepi- 
 tates slightly and becomes converted into powder of the peroxide. Its other properties in this condition 
 have not been thoroughly examined ; nor are they likely to present much interest except for merely 
 speculative, and, perhaps, for medicinal purposes. 
 
 In the condition of steel, on the other hand, all the peculiarities and habitudes of this metal are im- 
 portant enough to require a special detail and discussion in a separate article. (See Steel.) Under 
 this one will be considered what is proper to it in its two conditions of crude and malleable iron. The 
 means for artistically producing these two different states, i. e. the manufacture of cast or bar iron, being 
 different, must of course be detailed separately. In other regards they will be spoken of together, but 
 distinctly wherever necessary ; and it will be understood, that when not otherwise expressed, the term 
 iron means malleable iron. 
 
 Physical properties. The color of crude iron varies according to the state of combination and pro- 
 portion of its chief foreign ingredient, carbon, from dark gray to silvery white ; passing through divers 
 intermediate stages of gray, mottled, bright, and white. It is upon these indications, coupled with those 
 of texture, (which will be spoken of directly,) that the metal is classified in commerce. Dark gray iron, 
 crystalline, with small facets, is supposed to denote a fitness for foundry purposes, i. e. for being cast 
 into various forms ; and the denomination of such a whole class is foundry-iron, or founders' pig. As 
 its color brightens and grows more and more silvery, with a bladed texture, it is considered better 
 suited for conversion into malleable iron ; and the whole class obtains the name ordinarily of forge pig. 
 These distinctions, further than as applied to classes, are extremely loose and uncertain ; and we are 
 yet without positive knowledge as to either what causes or is a permanent practical consequence of 
 color in crude iron. In malleable iron the distinctions in this respect are much less marked. A full gray 
 hue, with something of a bluish tint, is generally supposed to attach to the best specimens. Of course, 
 all these remarks apply only to the phenomena of a fresh fracture ; and the color and lustre which may 
 be given to surfaces of iron in either condition by finishing and polishing are, it will be readily conceived, 
 entirely artificial, and dependent in no small degree upon the processes that may have been re- 
 sorted to. 
 
 In the same manner, it may be presumed, another property, which is chiefly superficial, is dependent 
 ipon the artistical processes employed in developing it, and this is the adhesion of iron, i. e. the force 
 w ith which it attaches itself to a liquid surface. This property has not been experimentally examined 
 to any extent, though a research upon it wrnuld probably be fruitful for all questions touching the fric- 
 tion of machinery, and, perhaps, would also shed light upon the internal structure of the metal. The 
 indefatigable Guyton-Morveau, only, has made observation upon it in the case of iron and several other 
 metals, by polishing with an equal amount of labor the face of a disk, one inch French in diameter, 
 (1'0658 in. English,) of the metals respectively, allowing each to repose an equal time upon the surface 
 of mercury in a dish, and then seeing what weight w T as sufficient to overcome the adhesion He found 
 
70 
 
 IRON. 
 
 the weight necessary in several cases (abstraction being made of that of the disks themselves respect' 
 ively) to be as under : 
 
 Gold required 446 gr. Fr. = 365 p 72 gr. Eng 
 Silver “ 429 “ = 351-78 “ 
 
 Tin “ 418 “ = 342-76 “ 
 
 Lead “ 372 “ = 30504 
 
 Bismuth “ 317 “ = 259'94 “ 
 
 Zinc required 204 gr. Fr. = 167-28 gr. Eng 
 Copper “ 140 “ = 114-80 “ 
 
 Antimony “ 126 “ = 103-32 “ 
 
 Iron “ 115 “ = 94-30 “ 
 
 Cobalt “ 8 “ = 6’56 “ 
 
 Although the adhesion of a surface in contact with the liquid in these experiments would be in part a 
 function of the aptitude of the metal itself to amalgamate with quicksilver, yet these results are nowise 
 accordant with such aptitude, as far as it can be inferred from other observations. And it seems to be 
 equally independent of the density and cohesion of the solid. It is probably dependent in much greater 
 degree upon the absolute perfection and smoothness of surface which, in bodies worked upon with the 
 same force and for the same time, manifests itself according to another property, that of hardness. In 
 ordinary speech, and sometimes even in exacter phrase, this term hardness is used to express the resist- 
 ance of a substance to change of form of any kind. Such resistance depends mainly upon cohesion and 
 elasticity, and covers, in part, the characteristics of malleability and stiffness. But hardness , in its tech- 
 nical sense, is resistance to removal or abrasion of substance, as in cutting, boring, filing, and the like. 
 Any material which will scratch a given substance is therefore harder than that substance. Kirwan 
 was the first to classify substances in this respect after a decimal scale, beginning with talc and ending 
 with diamond. The eight intermediate tests are uniform and easily accessible minerals. Measured by 
 such a scale, native iron (which may be considered as nearly the type of the malleable iron of commerce, 
 though it contains a notable proportion both of lead and copper, generally,) is ranked in hardness at 
 4'5 ; that is to say, it scratches fluor-spar as much as it is itself scratched by phosphate of lime. Crude 
 iron is harder, and most specimens of gray foundry pig are just scratched by felspar ; it may, therefore, 
 hold an average rank on Kir wan’s scale of 5'8. But white forge pig will generally cut glass, and may 
 therefore be ranked at 7 in hardness by the same scale. It will readily be understood that in applying 
 these tests, something depends upon the shape and sharpness of the fragment used ; a dull surface will 
 merely rub without scratching ; and in the case of white iron and glass, unless the lamellar crystals of 
 the former be used with then- edges, the latter will not be cut. It is the same with the diamond, the 
 hardest known substance ; only its spherical edges cut glass. In drawing a practical inference from such 
 observations, regard must be had, too, to the ordinary texture of the substances, i. e. their mode of ag- 
 gregation and cohesion. Thus white iron, hardened steel, quartz and granite, <fec., have all the same 
 theoretical index of hardness ; but steel, for instance, is much more coherent than quartz, which is a 
 brittle substance, and still more so granite ; it is, therefore, used readily for working both. So sand- 
 stone, which is principally grains of silica held together with a siliceous cement, and therefore has an 
 index of 7, is yet ordinarily worked with the same tools that are used for marble, whose index is but 
 3'5. But the causes and modes of these apparent inconsistencies readily manifest and reconcile them- 
 selves upon a little reflection. 
 
 .So far as metals are concerned, the following table may be taken to give what is known in this par 
 ticular ; the foregoing cautions being equally applicable. 
 
 ■; '.he probable Order cf their Hardness. 
 Iron, 
 
 Cobalt, 
 
 Nickel, 
 
 Crude Iron, (gray, ) 
 Steel, (soft,) 
 
 “ (hardened,) 
 Manganese, 
 
 Table of Metals v 
 
 Mercury, 
 
 Sodium, 
 
 Potassium. 
 
 Lead, 
 
 Zinc, 
 
 Tin, 
 
 Antimony, 
 
 Gold, 
 
 Silver, 
 
 Cadmium, 
 
 Bismuth, 
 
 Tellurium, 
 
 Copper, copper and zinc, (brass,) 
 Platinum, copper and tin, (gun-metal,) 
 Palladium, 
 
 Iron, 
 
 Titanium, 
 
 Crude Iron, (white,) 
 
 Chromium, 
 
 1th odium, 
 
 Iridium, Osmium, 
 
 Hardest steel, varying from white iron to the 
 top of the list. 
 
 How much hardness is dependent on texture , has been already mentioned ; and it is owing to the 
 varying circumstances of this last property that iron in different conditions is found to shift about so 
 much in the list just given. In practice, another property, that of affection by heat, or specific heat, 
 (which will presently be mentioned,) has also an influence; and a substance, hard at first, becomes 
 sensibly warm by attrition, and finally yields to the action of a material less hard than itself at low 
 temperatures, but endowed with a greater capacity for heat. It is thus in one aspect that crude iron 
 under a red heat may bo cut and sawn almost like wood ; and in the other, that a wheel of soft malle- 
 able iron, rapidly revolving, may be made to cut the hardest steel. W orkmen have the opportunity of 
 appreciating these affections in manipulations with the cold chisel. 
 
 The texture of crude iron is in most treatises said to be granular. It is in fact crystallized; as we 
 learn from the chemical experiments of Daniell, and the microscopic observations of Schafhaiitl and 
 Alexander. According to the last-named, the crystals of gray iron “ belong to the octahedral system, 
 [in which the axes of crystallization are equal and at right angles,] and present themselves under the 
 primary forms of several of its classes.” “The maximum limit of these, when cubic, is not above -^soo 
 
IRON. 
 
 71 
 
 of an inch in linear dimension, and about TTinnnr °f a grain in might.” Crystals in white iron 
 are smaller, and “ most frequently occur in six-sided prisms, sometimes connected in fascicles by their 
 sides, at others by their ends, in a sort of stellated or radiated arrangement, 'l’he white color of the 
 mass seems to be mainly arising from these arrangements of particles.” Malleable iron is supposed to 
 have a filamentous structure ; but metallurgists are not agreed how far this arises from (as it is cer- 
 tainly in some degree dependent on) the processes employed in the manufacture. The amount of forg 
 ing which the bars have undergone, the degree of heat to which they have been subject, as well as the 
 ultimate size to which they may have been reduced, all affect the texture of specimens, whose othei 
 characteristics, originally and subsequently, are apparently the same. Nevertheless, this property anil 
 that of color are the chief commercial tests of the quality of iron. It is generally supposed that a frac- 
 ture more pointed than irregular, and a tendency to become filamentous upon being forged into bars of 
 an inch square or under, are indications of the two main characteristics of good iron, viz. strength and 
 stiffness. But there is as yet no criterion by which, on simple inspection, the quality of the metal can 
 be determined, and both the manufacturer and the consumer are compelled to rely (iu the absence oi 
 actual experiment) upon the constancy of Nature in furnishing materials, and the uniformity of Art in 
 subjecting them to the same processes. The same ores treated in the same way ought to produce the 
 same metal ; and so they generally do. 
 
 Closely connected with texture is the property of density. The variations in this respect between 
 the results of different observers are to be attributed partly to the difference of methods, partly to the 
 inaccuracy of the weights employed, (a much more influential cause of error than is generally imagined,) 
 and partly to the variations of the individual specimens. Their limits are, however, sufficiently close 
 to allow of taking as a probable average (the density or specific gravity of distilled water being called 
 1) the specific gravity of 
 
 Crude iron, foundry or gray iron, 7 - 
 “ forge pig or white “ 7-5 
 
 Malleable iron, 7'6 
 
 In estimating absolute weight, it is sufficient for practical purposes to consider a cubic foot of dis- 
 tilled water as equal to 1000 ounces avoirdupois ; so that a cubic foot of iron in its different conditions 
 will weigh one thousand times the indices of specific gravity given above, respectively, in avoirdupois 
 ounces, sixteen of which go to the pound. For rough approximations, iron in general may be taken as 
 weighing one-fourth of a pound to the cubic inch. So far as crude iron is concerned, the specific gravity 
 has been recently considered in reports upon ordnance to the American government to be an index of 
 another physical property, (of the greatest interest where cannon and guns are concerned,) viz., the 
 tenacity or cohesive force of the metal. Of course, such indications are not regarded as absolute, but 
 merely relative ; and they have been supposed hitherto to apply only to the best sort of gray foundry 
 iron. 
 
 Upon this property of tenacity or cohesion of iron in its different conditions, experiments have been 
 very numerous and varied, with results as accordant as could be expected. They may be found de- 
 tailed more or less fully in several special treatises; such as of Barlow, Duleau, Karsten, Navier, and 
 Trcdgold. The results of those whose apparatus may be considered as the most reliable, seem to show 
 that cohesion depends not only upon the chemical composition of the metal, but also upon the way in 
 which it has been treated ; the amount of heat, for instance, to which it has been subject, the extent of 
 forging it has received, and also the dimensions which have been given to it, and the form in which it 
 lias been left. Were the theory of the resistance of materials perfect, the behavior of the metal under 
 one position or set of circumstances would determine for any or all ; but in the absence of such theory, 
 it is necessary here to give the observed results in the chief positions and circumstances in which the 
 resistance of iron is practically called into play. These are four, viz. : 1. Resistance to a force tending 
 to pull asunder in the direction of length ; this is usually termed absolute cohesion ; 2. Resistance to a 
 force tending to crush in the same direction; this is termed relative cohesion: 8. Resistance to a force 
 applied at any angle with the longitudinal axis of the mass, or a transverse force ; this is termed re- 
 spective cohesion : 4. Resistance to a twisting force, or to torsion. As to resistance to impact or resili- 
 ence, that will be spoken of under the property of elasticity. 
 
 1. The absolute cohesion of malleable iron may be taken for square bars of different sizes as under; 
 the resistance per square inch being proportioned to the breaking weight of the respective sizes. 
 
 In bars I inch square ; resistance per square inch = 90,000 lbs. 
 
 “ i “ “ “ =70,000 “ 
 
 “ 1 inch and over “ “ = 56,000 “ 
 
 When the bars are round with the same area, they will show a somewhat higher resistance than the 
 above; and w-hen forged flat they appear more resistant than when round. Iron wire, from the mode 
 of manufacture, is generally supposed to exert a greater proportionate resistance than hammered iron ; 
 but its average may be taken as included in the number given above. * In fact, the increase of resist- 
 ance inversely as the area seems to progress with wire to a certain point, when it changes sign, and 
 the proportionate strength diminishes with the area. Thus, in Telford’s experiments, 
 
 a wire ' inch in diameter gave a resistance per square inch of 94,080 lbs. 
 and “ ¥ ' T “ “ “ “ 80,192 “ 
 
 Dufours experiments, however, do not justify this inference. Annealed iron is hardly half as strong as 
 the same wire unannealed. All these numbers being extreme loads, it will be readily understood that 
 the metal ought never to be strained to such a limit. Up to a certain point, a bar or wire will stretch, 
 and when the strain is taken off, return to its former dimensions ; but beyond, although it will continue 
 to stretch, it returns no more, the alteration and injury are permanent. As a general rule, it is inju- 
 dicious to load iron with more than one-third of its breaking weight. The tables of Tredgold, which 
 are extensively used and found safe in practice, allow the strength of malleable iron in this sense at 
 
72 
 
 IRON. 
 
 17,800 lbs. per square inch, -which it can bear without permanent alteration. This may be taken foi 
 ordinary use at 18,000 lbs. per square inch. 
 
 Crude iron is but rarely employed as a tie ; so that a knowledge of its absolute cohesion is compara- 
 tively of little practical consequence, and there have been proportionably few direct experiments. The 
 mean of Tredgold’s gives 44,620 lbs. per square inch as the breaking weight. The results of Muschen 
 brock, Brown, and Rennie, the former very much in excess and the latter in defect, do not appeal 
 reliable. In practice, we may take 15,000 lbs. per square inch as the strain that gray crude iron will 
 bear in the direction of its length without permanent alteration. It is, therefore, about one-sixth weaker 
 than malleable iron. White crude iron has not been experimented upon in this sense ; but it is known, 
 from observations on transverse strains, to be much weaker than gray iron. Iron of the second fusion 
 [i. e. melted and cast from a cupola) is, in general, stronger than when run from the high-furnace. The 
 method of casting (i. e. in vertical or horizontal moulds) does not, as far as observed, affect its absolute 
 cohesion. 
 
 The following table gives the mean absolute cohesion of divers metals cast in pounds per square 
 inch, viz. : 
 
 
 
 Ratio. 
 
 Cast-steel, tilted 
 
 135,000 lbs.... 
 
 
 Crude iron, gray 
 
 45,000 “ ... 
 
 ...i- 
 
 Gun-metal, (copper and tin,) 34,000 “ ... 
 
 ...0-756 
 
 Brass, cast 
 
 20,000 “ ... 
 
 ...0-444 
 
 Gold, cast 
 
 20,000 “ ... 
 
 ...0-444 
 
 Tin, cast 
 
 4,700 lbs.... 
 
 Ratio 
 
 ...0-104 
 
 Zinc, cast 
 
 2,800 “ ... 
 
 ...0 062 
 
 Lead, cast 
 
 1,800 “ ... 
 
 ...0-040 
 
 Antimony cast, 
 
 1,000 “ ... 
 
 ...0-022 
 
 And the following the mean proportionate cohesion of some of them when drawn into wire ; iron wire 
 being 1, or unity. 
 
 Copper 0587 
 
 Platinum 0500 
 
 Silver 0'342 
 
 Gold 0-273 
 
 Gold 0-273 
 
 Zinc 0-200 
 
 Tin 0-064 
 
 Lead 0051 
 
 Iron l'OOO 
 
 2. In relative cohesion, or resistance to crushing, the two conditions of the metal appear to change 
 places ; crude iron being the strongest. The mean of many experiments of Karsten gives the resistance 
 in this sense of crude iron, gray, at 168,750 lbs. per square inch. 
 
 “ white, “ 210,540 “ “ 
 
 The specimens were of the first fusion, cast from a cupola, and poured from a reverberatory furnace ; 
 the cupola castings were very uniformly the weakest, and those from the air-furnace the strongest of 
 the sets. Those moulded vertically were also at a mean 2J per cent, stronger than those moulded 
 horizontally. Wrought-iron has not been extensively observed in this respect. The mean of the ex- 
 periments of Rondelet gives 70,000 lbs. per square inch (very nearly) as the weight under which bars 
 fron ^ to 1 inch square began to give way. Its texture appears to prevent it from being crushed, even 
 with the weight that would crush crude iron ; for if the height of the specimen be triple its thickness, it 
 will bend and double up sooner than be crushed. The practical effect in either case upon the equilib- 
 rium of constructions is pretty nearly the same. We are warranted, then, in considering the useful rela- 
 tive cohesion of wrought-iron at one-half that of gray crude iron. The following table exhibits this 
 property as supposed to be ascertained for some other metals, viz. : 
 
 Crude iron, white, resistance per cubic inch, 
 
 210,000 lbs. 
 
 ratio l'OOOO 
 
 “ g ra y. 
 
 170,000 “ 
 
 “ 0-8095 
 
 Copper, cast, 
 
 117,000 “ 
 
 “ 0-5571 
 
 Malleable iron, “ 
 
 85,000 “ 
 
 “ 0-4048 
 
 Copper, wrought, 
 
 55,000 “ 
 
 “ 0-2620 
 
 Tin, cast, “ 
 
 9,000 “ 
 
 “ 00429 
 
 Lead, cast, 
 
 8,000 “ 
 
 “ 0-0381 
 
 The last four were not crumbled under the pressure, but flattened; their resistance was therefore 
 entirely overcome ; although their texture did not allow the same phenomena as belong to the crystal- 
 lized structure of the others. 
 
 3. Experiments on respective cohesion of iron, i. e. its resistance to transverse strains, have been very 
 numerous. Theoretically, their results should be functions of the absolute cohesion of the substance ; 
 but, partly from defect of theory, and partly from inherent difficulties and errors in observation, this is 
 not exactly the case. As this is the sort of resistance most extensively required in practice, its deter- 
 mination is of the greatest interest. In addition to the variations arising from the qualities of the metal 
 itself, it depends so much upon the dimensions and position of the mass exposed to strain, upon the 
 ano-le of direction of the force or weight, and upon the degree of deflection that the equilibrium of con- 
 struction will allow, that the statement of results can hardly be niore condensed than the statistics ot 
 the experiments themselves. To give tables for practical use is liable to the same objection of taking 
 up undue space, and also to the inconvenience of being limited in their application. All that will be 
 done here, then, is to furnish genel al rules which may safely be calculated upon in all cases for appor- 
 tioning the weight to the dimensions of the beam which is to bear it, viz. : 
 
 100000 
 
 bd\ 
 
 IF ’ 
 
 for gray crude iron. 
 
 w 
 
 -j] 
 
 bd 3 , 
 
 .= 62600-^-; lor white 
 b d 3 
 
 = 135000 — ; for wrought-iron. 
 
IRON. 
 
 73 
 
 Practical Rule . — Divide the product of the breadth of the beam ar.d the cube of the depth by the 
 square of the length, all in inches; and multiply the quotient by 100,000 for the weight in pounds 
 v. hen gray iron is used. With white iron multiply by 62,500 ; and with malleable iron, by 135,000 foi 
 the load in pounds. These coefficients correspond to a maximum deflection in the middle of the beam 
 (which is assumed to be solid) of -g B of an inch per foot in length ; which it is not judicious to exceed, 
 although it is very often surpassed. The use of white iron should be as much as possible avoided in 
 resisting strains of this kind. It is not only very little more than half as strong, but it is also less uni 
 form and more uncertain. * 
 
 These formulae and rules apply to instances where the beam is supported at both ends, and strained 
 by a force acting in the middle of the length, as in the case of mill-shafts, &c. Where the load is uni- 
 formly distributed over the length of such a supported beam, the effect is the same as if five-eighths ol 
 this load were applied in the middle of the length, and the weight borne in this case will be l T 6 ff 
 times that ascertained by the rule just given. 
 
 When the beam is square, the formula and rules equally apply as when it is merely rectangular. If 
 it be cylindrical, supported at both ends and loaded in the middle, divide the weight obtained by the 
 rule for a square beam whose side equals the given diameter by lyA for the load that will produce the 
 same deflection. If the load is to be uniformly distributed over the length of a cylindrical beam, it is 
 near enough in practice to consider that its strength and stiffness will be the same as in a square beam 
 with sides equal to the diameter of the cylinder, and loaded with the same weight in the middle of it? 
 length. 
 
 In all these cases, the weight of the beam itself must be taken into the account as part of the load, 
 either uniformly distributed or centered in the proportion of 5 : 8, as the case may require. To diminish 
 as far as possible the useless load in such instances, it is not unusual to make the beam or shaft a hol- 
 low cylinder. The rule for determining the dimensions becomes complicated ; for strength and stiffness 
 do not follow the same ratio of diameters. In general, it may be remembered that when the thick- 
 ness of the metal is one-fifth of the diameter, (which, if the load is considerable, is not more than a safe 
 proportion,) the strength of the hollow cylinder is nearly two-thirds, and the stiffness one-half nearly of 
 what they would be respectively in a square beam of the same depth, while there is a saving of one- 
 half the quantity of metal. 
 
 4. The capacity to resist torsion is of great importance in the substance of which the revolving parts 
 of machinery are made ; for it is not unfrequently by a submission to torsion that both power and dura- 
 bility are secured. Navier has explored the theory of this resistance ; but the experimental constants 
 which are required to make the theory of practical application are unfortunately deficient. The results 
 of the observations made hitherto are remarkably discordant. The following table gives the propor- 
 tionate resistance in this respect of various metals. 
 
 Cast-steel, 19 '5 6 
 
 Shear “ 17'06 
 
 Blister “ IG‘69 
 
 Crude iron, (cast vertical,) 1063 
 
 Wrought-iron, (coal,) 10T3 
 
 “ (charcoal,) 9'50 
 
 Crude iron, (cast horizontal,) 9'94 
 
 Hard gun-metal 5'00 
 
 Fine brass, 4 69 
 
 Copper, (cast,) 4 - 31 
 
 Tin, 144 
 
 Lead,.... TOO 
 
 It appears from this, that iron in all its conditions exercises this resistance pre-eminently ; and that 
 crude iron does not differ in this respect materially from wrought-iron. It has been generally assumed 
 in metallurgic treatises hitherto, that resistance to torsion is in proportion to absolute cohesion. The ex- 
 periments, so far, do not sustain this, as between malleable and crude iron. 
 
 In a preceding paragraph, a distinction has been made between strength and stiffness. Although 
 both are in part functions of the absolute cohesion, yet the latter is a measure more particularly of 
 another physical property — that of elasticity. It is in virtue of its cohesive strength that a substance 
 resists any change of form or position ; it is in proportion to its elasticity that such changes, when occur- 
 ring, are not permanent. Thus, up to a certain point, a bar or wire which has been lengthened by a 
 strain will, when the strain is removed, return to its original length ; or a beam that has been deflected 
 by a load will, upon being relieved from the load, reassume its horizontal position. When this point is 
 passed, and the extension or deflection remain permanent after the cause producing them has ceased to 
 act, we say ordinarily that the piece, whatever it may be, has taken a set, and, technically, that its elas- 
 ticity is overcome or destroyed. Gray crude iron will allow an extension, within the limits of its elas- 
 ticity to recover, of -j-^Vo °t its original length when the strain is acting in that direction : it is not safe 
 to allow for a greater deflection in masses which have to bear a permanent load, (such as joists, girders, 
 <fcc.,) than fff- of an inch for each foot in length, or say of the length, in round numbers. White iron 
 is not reliable either for extension or deflection. Malleable iron will bear an extension without injury of 
 i'tVtt ds length, only its deflection ought not to be allowed to surpass of its length. These de- 
 flections are of course measured where they are the greatest, viz. in the middle of the length. 
 
 There is another manifestation of elasticity in resistance to impact, or, as it is technically termed, in 
 resilience ; in virtue of which a s’’Vtance yields in form or position to the momentum of a sudden im- 
 pulse or blow, and then returns to its original state. This resistance is of great importance in machinery, 
 to aid in determining what velocity the moving masses should be allowed to have ; for the impact and 
 shock are the same whether the substance in question strikes against a body at rest, or, itself at rest 
 :s struck by a body in motion. In theory, resilience is a function of absolute cohesion, and of density as 
 (veil as of elasticity ; and hence certain woods possess this property in a higher degree than many 
 metals, and nearly as high as iron itself. Whalebor exhibits it in a pre-eminent degree. 
 
74 
 
 IRON. 
 
 Table showing the •proportionate Resilience or Resistance to Impact of divers Substances. 
 
 Iron, (crude or wrought,) T000 
 
 Gun-metal, (copper 8 + tin 1,) cast 0819 
 
 Yellow Pine, (American,) 0-740 
 
 Oak, (English,) 0'724 
 
 Mahogany, 0-630 
 
 Elm, (English,) O620 
 
 Ash,. 0600 
 
 White Fir, 0 567 
 
 Iron, (crude or wrought,) . 1 000 
 
 Brass, (cast,) 0-400 
 
 Beech, 0’326 
 
 Larch 0-315 
 
 Lead, (cast,) 0-246 
 
 Zinc, “ 0190 
 
 Tin, “ 0142 
 
 Whalebone, 3 000 
 
 The following comparative summary may be taken of the chief practical resistances of iron and some 
 other substances employed in constructions and in machinery. 
 
 Crude iron, (gray.) 
 
 Brass, 
 
 Gun-metal, (copper and tin,) 
 
 Iron, (malleable,) 
 
 Lead, 
 
 Marble, (white,) 
 
 Oak, 
 
 Tin, 
 
 Zinc, 
 
 Strength. 
 
 Extensibility. 
 
 Stiffness. 
 
 . 1-00 
 
 1-00 
 
 1-00 
 
 .. 0-44 
 
 0-90 
 
 0-49 
 
 . 0-65 
 
 1-25 
 
 0'54 
 
 . 1-12 
 
 0-80 
 
 1-35 
 
 .. o-io 
 
 2-50 
 
 0-04 
 
 
 1-00 
 
 0-14 
 
 . 0-25 
 
 2-80 
 
 0-09 
 
 . 0T8 
 
 0-75 
 
 0-25 
 
 .. 0-37 
 
 0-50 
 
 0-76 
 
 The remaining properties of iron connected with its texture do not, as yet, admit of being numerically 
 valued or proportioned. Such is the case, for instance, with malleability, or the capacity of being ex- 
 tended in one or more directions by hammering. White crude iron does not display this property at 
 all; gray iron possesses it generally in a slight, and sometimes in a considerable degree. Wrought- 
 iron in this respect is inferior to gold, silver, copper, tin, cadmium, platinum, lead, and zinc; the order 
 of the names here representing the order of malleability in actual extent of surface which can be given 
 to a unitary mass of the same volume, by the most suitable treatment. All other metals are inferior 
 to iron in this aspect ; though, if the question were as to the extent of surface which could be gained by 
 a continuous hammering, its relations would be altered. It tends to become very brittle by forging; 
 and, besides requiring the application of great force in the aggregate, has to be frequently softened by 
 heat during the process. The harder the iron is in its original state as wrought-iron, the more often 
 ?neh softening has to be resorted to ; whence it may be inferred that, ceteris paribus, the softer the iron 
 the more malleable it should be. And the same inference attaches in the property of ductility, or capa- 
 city for being drawn into wire. This is in so far different from malleability, that heat is a necessary 
 part of the process if it is carried to any great degree ; afid the order of ductility of the several metals 
 varies from that of their malleability accordingly. Gold, silver, and platinum are the only metals more 
 ductile than iron. 
 
 Magnetism, or the property of permanent polarity, was formerly supposed to belong to iron only. 
 Later researches show that this is to be shared, though not equally, with nickel, cobalt, and chromium. 
 Occasional magnetism may be excited in most substances ; as is shown by their influencing the oscilla- 
 tions of a freely suspended magnetic needle. But this influence is much weaker in all other substances 
 than the four named. Silver, which stands the highest of all the other metals, is nine times feebler in 
 this respect than iron ; gold fifteen times, and marble nearly twenty times, more weak. Iron acquires 
 magnetism by contact or suitable friction with a magnet ; by being suitably rubbed or struck in a 
 proper position ; by exposure to refracted light of the sun ; and even by being left to stand in a nearly 
 vertical position. The processes for this purpose will be described under the proper article. (See Mag- 
 netism.) It is enough to say here, that owing to the ease with which it is accidentally developed, it is 
 extremely difficult to find in the shop of a philosophical instrument-maker, for instance, a tool or scrap 
 of iron which is not in some degree magnetic. In all its conditions and states it is susceptible of this 
 property, but develops it differently in each. Thus, gray crude iron becomes sooner and more intensely 
 magnetic than white iron ; but yields in both these regards to wrought-iron and to steel. Soft ductile 
 iron is more easily and more strongly magnetizable than steel, but does not retain its magnetism as 
 well. A similar relation is observable between untempered and tempered steel. The magnetism of 
 iron may be weakened or lost by methods similar to those which originally impressed it. 'The filings 
 of a magnet are less magnetic than the solid mass. A heavy, sudden blow or shock, against a hard 
 body, will sometimes destroy magnetism. Heat always diminishes it ; although there are some pecu- 
 liarities which have been observed in this regard that are difficult of explanation. It undergoes dete- 
 rioration whenever similar poles of two equally strong magnets are kept in prolonged contact ; and 
 finally, is always abated by alloying with other substances, and may be destroyed entirely by increasing 
 the proportion of alloy. Arsenic is, in this regard, the most active of the metals ; though an alloy of 
 two-thirds arsenic does not entirely prevent the mass from being attracted by the needle. Mushet, 
 however, affirms that twenty-two per cent, of manganese effectually destroys magnetism in an alloy 
 of iron. 
 
 Malleable iron is an excellent conductor of electricity ; and although in this respect inferior to copper 
 and zinc among the easily oxidized metals, and to gold, silver, and platinum among the others, it is yet, 
 for economy, universally employed for lightning-rods. In the Voltaic pile it follows zinc in the order ot 
 electro-positive metals. 
 
 Its electro-magnetic properties are very remarkable, in the facility with which it is converted into a 
 magnet of great energy during the passage through it of an electric current. It is to this that the elec 
 tro-magnetic telegraph owes, in part, :.ts adaptation and success. 
 
IRON. 
 
 75 
 
 Hitherto the properties of iron have been considered as manifesting themselves at ordinary tempera- 
 tures. It temains to speak of the modifications and peculiarities which arise from its affection hy heat 
 Of all the metals, this lias the greatest specific heat ; i. e. the greatest capacity for heat, or faculty of 
 resisting change of temperature. It bears a greater quantity of caloric for a longer time, and with less 
 alteration of its own sensible temperature. The index of its specific heat has been observed by Dulong 
 
 and Petit as follows : 
 
 32° F. to 212° F 0T098 
 
 392° F 0T150 
 
 572° F 0T218 
 
 662° F 0T255 
 
 Supposing the capacity for heat to augment in the same ratio, we would have at the supposed epoch 
 of red-heat an index - 0T402, and near the probable point of fusion = 0'3282 ; that of water in equal 
 
 weight being P000. The specific heat varies according to the condition of the metal, and appears to 
 be in some proportion to the quantity of carbon associated in each. Thus the specific heat of steel, as 
 observed by Regnault, is represented by the index = 0T1848, and that of white crude iron ~ 0T2983. 
 Gray crude iron, as far as may be inferred from observations of refined iron, would have a lower index 
 than white iron, but there are not observations to settle this. 
 
 The expansion of iron by heat presents it in a similarly advantageous character. It expands less 
 than any of the metals except platinum, palladium, and antimony. The observations hitherto have 
 been made principally upon its expansion in one direction ; i. c. its linear expansion, or extension. It is 
 supposed to be accurate enough for practice to consider this extension as equal in all directions, and as, 
 therefore, the one-third of the cubic expansion. All the experiments upon the extension of crude iron 
 have been with metal of the second fusion, which is almost always gray. It may be presumed from 
 practical phenomena on the large scale, that white iron expands less than gray. The mean of the re- 
 sults of Roy, Lavoisier, and Daniell with cast-iron, gives an extension in length of 0-0010974249 between 
 32° F. and 212° F. ; the original length being 1' at 32° F. This corresponds to an extension (suffi- 
 ciently accurate for practical use) of T __2__ T of the original length at 32° for each degree of Fah- 
 renheit. The extension of wrought-iron has been more frequently and more variantly observed. The 
 results lie between 0 000600 of Bonguer and 0-001446 of Hallstrom, as the extension on a length origi- 
 nally I - at 32° F. Theoretical considerations, as well as an average of the most reliable observations 
 determine this extension at 0'0011356 for 180° between the melting of ice and the boiling of water ; 
 corresponding to Yorjrfa orr of the original unity for 1° F. The extension of steel appears to be uni- 
 formly higher than this, and to vary according to the temper of the metal in that condition. (See 
 Steel.) Between the limits given, the rate of expansion may be taken as constant for each degree, 
 although in strictness such is not the fact ; beyond 212° F. it would not be proper to rely upon such an 
 assumed constancy : but at these higher temperatures a knowledge of the dilatation is chiefly interest- 
 Ag in theoretical science. Rinman supposed, from some observations, that between ordinary summer- 
 heat (say 76° F.) and what is called red-heat, crude iron extended ^ and wrought-iron - [ (T of its 
 original length : but these estimates can hardly be relied upon. The following table presents the most 
 probable values in this particular, as well as certain other phenomena : 
 
 Table showing the actual Extension of Wrought-iron at various Temperatures. 
 
 -ee of Fahrenheit. 
 
 T_.ength . 
 
 20 ° 
 
 1- 
 
 91 9 . 
 
 1-0011356 
 
 392 
 
 1-0025757 ) 
 
 572 
 
 1-0043253 V 
 
 752 
 
 1-0063894 ) 
 
 932 
 
 1-0087730 \ 
 
 112 
 
 1-0114811 ) 
 
 !S52 
 
 1-0216024 \ 
 
 2192 
 
 
 -’732 
 
 1-0512815 ) 
 
 2912 
 
 cohesion destroyed. 
 
 Surface becomes straw-colored, deep yellow, crimson, 
 violet, purple, deep blue, bright blue. 
 
 Surface becomes dull, and then bright red. 
 
 Fusion perfect. 
 
 In the property of conducting heat, iron occupies a low rank. The following statement is warranted 
 by the observations of Dergnetz : 
 
 Substances. Conducting Power. 
 
 Gold 2-6728 
 
 Platinum 2 6223 
 
 Silver 2-6009 
 
 Copper 2-4010 
 
 Zinc 09722 
 
 Iron 1- 
 
 Substances. Conducting Power. 
 
 Ikon T 
 
 Tin 0-8121 
 
 Lead 0-4801 
 
 Marble 0-0625 
 
 Porcelain 0-0326 
 
 Brick-clay 0-0302 
 
 These observations refer to malleable iron. Crude iron, whose specific heat is greater than its dilatabilitv 
 is less than the same properties of wrought-iron, is, it may be inferred, a worse conductor. Upon its power 
 of absorption, radiation, and reflection of heat, in either condition, there have been no reliable observations. 
 
 Besides the influence upon dilatation, an effect seems to be produced upon the cohesive force of iron 
 by temperatures either higher or lower than ordinary. In regard to low temperatures, it may be 
 assumed, in general, that they promote fragility. It is uniformly observed that iron is much more 
 brittle in winter than in summer ; and this holds good equally for all conditions of the metal. Cold 
 weather is, therefore, unfavorable for any practical test of quality, (such as for cannon, chain-cables, die.; j 
 
76 
 
 IRON. 
 
 especially one dependent in any way upon impact. On the other hand, with temperatures higher that 
 ordinary, but yet below the point of boiling water, Tredgold supposes the absolute cohesion to be di 
 minished by an elevation of 1°F. in temperature. Under temperatures which . transcend thr 
 
 boiling point of water, the table given above has already indicated the most remarkable phenomenon— 
 the iridescence or succession of colors during the augmenting application of heat. To what this effect is 
 owing is not known ; partially, perhaps, to the color produced by the contact of thin plates, and par- 
 tially to an oxidation of surface. This last cause is assured by the permanence of the color after the 
 heat has ceased to be applied. The straw color is developed fully at 400° F., the fusing point of tin ; 
 the deep yellow occurs at 420° F. ; crimson follows at 450° F., where bismuth fuses ; from that vio'et, 
 purple, and deep blue succeed, till 540° F., the melting point of lead ; this blue brightens, passes into 
 sea-green, and at last disappears at 700° F., the fusing point of zinc. Beyond this, the epochs of tem- 
 perature have no distinctive test. But if the heat is continued, there occurs a secondary, and, finally, 
 just before red heat, a tertiary succession of the same color and in the same order, only less vivid and 
 less lasting. If the metal be withdrawn at the close of this tertiary series, its surface will be found 
 covered with a thin pellicle of oxide, whose constitution has not yet been examined. The practical 
 utility of these color-tests is principally found with steel, where they serve as guides to determine the 
 probable temper imparted. The deep-blue color is also used in the arts as an ornamental and anti- 
 oxidable tint. Iron, in its different conditions, is not similarly affected in this respect. In general, steel 
 is colored at a lower temperature than what has been given as applicable to the case of malleable iron, 
 and gray iron at a higher one. White iron has not been as yet experimented on. But as there is rea- 
 son to conclude that the colors occur in the direct ratio of the hardness of the metal, white crude iron 
 may be expected to surpass steel. Of the same bar, the harder and softer portions are emphatically 
 designated in this process. The coloring thus depending on hardness, its brilliancy is determined by the 
 state of polish of the surface. And as the hardness of the metal thus influences the phenomena of 
 colors, so it is in its turn reacted on by the heat which produces them. It is on this account that iron 
 which has become hard in being wrought and hammered, is exposed to heat in order to soften it, as has 
 been noticed before. The degree of heat requisite is in proportion to the hardness existing and to the 
 softness required : in practice, however, it is generally a full-red heat. Iron, in all its conditions, ap- 
 pears to be permanently softened by being thus heated, whatever may have been its character or 
 treatment before. The hardness and brittleness which may be cured by this resort, must be distin- 
 guished from the same characteristics arising from a peculiar chemical composition. Thus, there is a 
 sort of iron which becomes brittle by the application of heat. Metal of this class is well known under 
 the name red-short, or hot-short, and is met with in all conditions. Again, there is a kind of iron pre- 
 cisely opposite : brittle at ordinary temperatures, it becomes tenacious when hot ; though, like the other, it 
 undergoes no permanent change, and the modified characteristic belongs only to the modified temperature. 
 
 Sudden cooling appears to augment the effect of low temperature, and to impart greater or less 
 hardness to the metal, according to its previous quality. In the ease of steel, this is of the utmost 
 interest ; for on it depends the whole business of tempering. In other conditions the effect is less 
 maiked, but sufficiently sensible whenever the conducting power of the cooling material is not out of 
 proportion to the mass of metal acted upon. The conducting power of the air is never sufficient, ordi- 
 narily, to produce any of the phenomena of sudden cooling : exposed to that, the cooling is always 
 slow, and, according to its temperature, follows, more or less, th ? softening effects which have been 
 already spoken of, and which are technically known as annealing. But this will be spoken of more 
 particularly under the metallurgic treatment of iron. 
 
 The effect of sudden cooling is more manifest in temperatures higher than red heat, and especially 
 upon the metal in fusion. The observation of this is more readily made upon crude than wrought-iron ; 
 and the most remarkable effect is the conversion of gray iron into white, which takes place more or less* 
 completely in proportion (other things being equal) to the mass operated upon. On the other hand, 
 white iron can be converted into gray by an opposite method of treatment ; and this not only on the 
 small scale, but also in large. Indeed, as was said before, iron of the second fusion, allowed to cool 
 slowly, is almost uniformly gray. But gray iron, cast in moulds of any sort which conduct heat with 
 sufficient rapidity, (such as cast-iron moulds,) uniformly chills, as it is termed ; i. e., becomes converted, 
 to a greater or less depth from the surface, into white iron. Practical advantage is taken of this in the 
 manufacture of wheels for railroad cars, which are always purposely chilled to increase their durability. 
 
 It is at temperatures above red heat that the most important and practically useful modifications of 
 this metal take place in all its conditions. Not to refer any further to steel, the welding of malleable 
 iron and the fusion of crude iron, by which either of these are made applicable to the arts and wants oi 
 mankind, occur at about the same epoch of temperature, somewhat further removed from red heat than 
 this last is from ordinary states. The table before given has already indicated the temperature of the 
 probable fusion of malleable iron, which is a little above that of crude iron. The uncertain indications 
 of Wedgwood’s pyrometer for a long time induced an erroneous estimate of the amount of heat required 
 for the fusion of metals generally, and especially that of iron. Daniell has shown, by experiment with 
 a much more reliable apparatus than that of Wedgwood, that cast-iron (so called) cannot require a 
 higher temperature for fusion than would be expressed by 2786° F.; while Alexander has demonstrated, 
 from the known relations and properties of cohesive force and specific heat, that bar-iron (whose utter 
 infusibility was long maintained) must become fluid at about 2774° Fahr. We are yet deficient in a 
 pyrometer whose indications would be uniform when applied in temperatures as high as this, a desid- 
 eratum whose supply would contribute materially to the filling up of /he theory of the manufacture ot 
 iron. It is probable that an air-thermometer, whose tube, where it entered the furnace, is of platinum, 
 would afford the most unexceptionable and reliable results. 
 
 The capacity for being welded, i. e. performing an intimate and perfect union of two surfaces, occurs 
 at the epoch of incipient fusion. This property is possessed by iron alone of all the metals, except pla- 
 tinum and palladium. White crude iron, under ordinary treatment, does not show this characteristic 
 
IRON. 
 
 / i 
 
 at all. Gray iron is weldable, but in such narrow limits of temperature that the operation has to be 
 effected with great quickness in order to succeed. With bar-iron and steel, in sufficient masses, welding 
 is of every-day application. If the masses be very small, they cool too quickly to be welded in the 
 ordinary way. Crude iron in fusion occupies a less space than when solid ; in this respect its anomaly 
 (which is to be traced to crystallization) is shared with antimony, bismuth, sulphur, and zinc, among the 
 metals, all of which shrink in melting. The same may be observed c.f water, which is more dense when 
 fluid than when crystallized in the shape of ice. If a mass of crude iron be made hot and laid upon a 
 bath of melted metal, it floats ; but if it be cold, it tends to sink. Perhaps this may be owing to die 
 repulsive effect of heat. White iron, in this respect, shrinks less than gray. On an average, good gray 
 foundry iron shrinks rather more than the ? o^Vo o °f * ts volume when cold. The general allowance of 
 the founders in making their patterns is g of an inch to the foot lineal. 
 
 Exposed to heat at any temperature from red heat upwards, witli access of air, iron, in all its condi- 
 tions, is readily covered with a coating of oxide. Bar-iron is thus oxidated more easily than crude 
 iron ; and of this latter, gray iron forms, at the same temperature, a more friable oxide than white. 
 The following contrast may be taken to exhibit the most important characteristics of the two conditions 
 of crude iron when exposed to high temperatures, viz. : — 
 
 Gray Iron 
 
 Is less easily oxidated ; preserves its character 
 longer, but loses it (cohesion, &c.) more completely 
 at last; suffers these changes more when protected 
 from the air ; heated below the fusing-point, with 
 access of air, demands more heat and more air to 
 assume a certain malleability ; requires a higher 
 temperature for fusion ; when fused is more liquid ; 
 expands more in cooling ; fused rapidly and cooled 
 quickly, tends to become white ; fused rapidly and 
 cooled slowly, retains its character or becomes 
 more soft. 
 
 White Iron 
 
 Is more easily oxidated ; loses its character sooner, 
 and becomes granular, grayish, and steel-like in 
 malleability and temper ; suffers these changes 
 more when protected from the air ; heated below 
 the fusing-point, with access of air, becomes quite 
 malleable, and may be tempered to take an edge ; 
 fuses at a lower temperature ; when fused is less 
 liquid and more pasty ; expands less in cooling ; 
 fused rapidly and cooled quickly, becomes ex- 
 tremely brittle ; fused rapidly and cooled slowly, 
 becomes gray. 
 
 The precautions necessary in view of these peculiarities, as well as the general processes, will be de- 
 scribed under the head of Bounding ; and what has been said may be considered as covering the chief 
 physical properties of the metal. 
 
 Chemical affinities and reactions. — These have been observed for the most part with the iron of com- 
 merce, which is never entirely pure, but contains carbon, silicon, phosphorus, sulphur, arsenic, chromium, 
 titanium, magnesium, aluminum, and manganese, in very minute proportions. Nitrogen is sometimes 
 met with ; but oxygen, which was formerly considered a constituent, has not been recognized in the 
 later researches of the most accurate chemists. The chemical symbol of iron is Fe, and its atomic 
 weight 339-205, oxygen being taken as 100. In the system where hydrogen = 1- the atomic weight of 
 iron is 28 - , as an average round number. 
 
 With oxygen, iron combines in two proportions, whose resulting compounds appear capable of fresh 
 combinations, so that in point of fact four compounds are known to exist. The first is the state of pro- 
 toxide, which does not exist naturally nor artificially, except as a hydrate. The second in the proportion 
 of oxygen is the forge-cinder , formed on the surface of the metal by heat, with access of air, and thrown 
 off under the hammer or squeezer. The third is the black or magnetic oxide, (the oxidum ferroso- 
 ferricum of Berzelius,) which exists also naturally; and the fourth is the peroxide, red oxide, or sesqv.i- 
 oxide, the first and last of which epithets are used according to different theories of its constitution. This 
 also exists as a mineral, under the name of red hematite, and is massive, fibrous, or crystallized, according 
 to circumstances. Its hydrate is known to mineralogists as brown hematite. 
 
 The following tabic contains all that need be given about these oxides : — 
 
 Composition. Atoms. Proportionate 
 
 Name. Iron. Oxygen. Iron. Oxygen. Iron. Oxyg. Index of Oxygei 
 
 Protoxide 0-T723 + 02277 100 + 29'48 3 + 6 24 
 
 Forge-cinder 0-7516 + 0-2474 100 + 32-90 3 + 7 27 
 
 Magnetic oxide 0-7178 + 0-2821 100 + 39'30 3 + 8 82 
 
 Peroxide 0-6934 + 0-3066 100 + 4422 3 + 9 36 
 
 The three first are attracted by the magnet, the last is not. The colors which have been before spoken 
 of as accompanying different degrees of the application of heat, are also doubtless due to the formation 
 of oxides, whose constitution, however, is not known. The affinity of iron for oxygen appears to be in 
 proportion to its own purity, and also, though in a less degree, to the state of its surface. So, in respect 
 to that peroxidation which is very familiar as rust, and which tends to occur more or less upon this 
 metal when exposed to the action of the air, (and especially damp air,) white iron is less affected than 
 gray, and any crude or cast-iron less than the malleable metal. This difference of the different condi- 
 tions holds good in the case of moisture alone, and in general with most chemical agencies. 
 
 Pure viater, disengaged of air, does not act upon iron at all at ordinary temperatures. Above 120° 
 Fahr., the water is slowly decomposed, and yields its oxygen ; at 212° Falir., the decomposition is quite 
 sensible ; and at a red heat it is very rapid, hydrogen is given off, and magnetic oxide formed. At 
 intermediate degrees, the action is nearly in proportion to the temperature. In practical cases, where 
 the oxidation of the metal is an inconvenience, (as in steam-boilers, &c.,) it may be remedied to a con- 
 siderable extent by the introduction of other metals having a greater affinity for oxygen. Pieces oi 
 zinc, for instance, will serve the purpose very well, to keep the boiler clean and unimpaired. Impure 
 water acts in proportion to the activity of the salts it may happen to hold in solution, and differently 
 upon different conditions of the metal. Thus, sea-water, which merely gives a coat of oxide to bar-iron 
 
IRON. 
 
 (anchors, chain-cables, (fee.) to a depth proportionate, but in a diminishing ratio, to the time of immer 
 sion, converts cast-iron (cannon, cannon-balls, (fee.) into a substance resembling plumbago, or graphite, 
 i. e. into carbon, associated with metallic and oxygenated iron. Such conversion appears to be less with 
 white than gray iron. 
 
 Air and moisture together appear to exercise a more powerful agency in producing oxidation than 
 either separately, and as this is precisely the joint influence to which this metal is in most practical 
 cases exposed, there is the more interest in providing a preservative. This is found not only, as was 
 said just now, in the polish of the surface, but also in the means by which such polish is produced, in 
 special coatings of substances which resist humidity, and also in the protecting action of incipient oxida- 
 tion itself. Thus, in the first instance, a polish acquired under the use of oils (and still more as those 
 oils may be themselves unalterable) is more lasting than one obtained with water. One of the best 
 preservatives of the second kind, is a solution of caoutchouc in oil of turpentine, which is applied upon 
 the polished surface, and is then removed, or rather brought down to extreme thinness, by a brush 
 dipped in the same oil, heated. Among the third sort has been already mentioned the bluing, which is 
 effected by a temperature of about 550° F. ; and bronzing, as it is called, is of similar result. This is 
 done by washing the surface, which should be smooth, with acids, and mostly hydrochloric acid, ex- 
 posing it for a suitable time to the air, until it becomes thoroughly covered with a uniform coat of oxide, 
 and then removing that rust with olive-oil as a menstruum, until the surface ceases to soil white linen. 
 This is the common resort for gun-barrels. Electric gilding, (see Gilding,) although beginning to be 
 extensively used in the bright parts of machinery, which are not subject to friction, does not come prop- 
 erly in the category of the preservatives we have been considering. 
 
 The combination of carbon with iron gives rise, in fact, to the different conditions of this metah In 
 white iron and steel it is chemically combined with the mass ; in gray iron it is partly combined in poly- 
 carburets dispersed about the mass, and partly free, as graphite, (called, by the workmen, Jcish ;) in 
 malleable iron it does not exist at all, or only in insignificant proportions. Karsten considers 5'3 per 
 cent, as the limit of saturation, which would give for the atomic constitution of the percarburet, one atom 
 of carbon to four atoms of iron. In gray iron the whole quantity of carbon does not, at a maximum, 
 exceed 4 per cent., of which 1 per cent, may be taken as combined, and 3 per cent, to be mechanically 
 associated as graphite. Although the occurrence of carbon is the principal modifier of the condition of 
 this metal, it is probable that the differences, so far as crude iron is concerned, are owing to other asso- 
 ciations also. Thus, as nitrogen has been found only in white iron, it is likely that some of its charac- 
 teristics depend upon the formation of compounds of nitrogen and carbon, and, ultimately, of cyanurets 
 of iron. It is very much to be desired that this suggestion could be studied in the synthetic way. The 
 practical precautions which have to be taken in consequence of the affinity of iron for carbon, will be 
 referred to hereafter, under the head of Foundry, and also under the article Steel. 
 
 Sulphur combines with iron in several definite proportions, both artificially and in nature. Until the 
 proportion reaches 2 atoms of sulphur for 1 atom of iron, (or 53 per cent, sulphur nearly,) the compound 
 is attracted by the magnet. This proportion may be considered as that of the natural magnetic pyrites. 
 Four atoms of sulphur to one of iron constitutes the common iron pyrites. Sulphur promotes the fusi- 
 bility of iron extremely, so much so that a plate or bar of iron, kept only at a red heat, may be pierced 
 to a considerable depth (say an inch, or more) by a stick of sulphur. Unfortunately, the quality of the 
 metal becomes so far impaired as not to allow avail of this peculiarity in the arts. Sulphur combined 
 with iron causes brittleness at all temperatures, and especially what has been before spoken of as red- 
 shortness. Experiment has shown that of sulphur is enough to produce the first characteristic, 
 and — ^ A__ the second. It is hence that many ores cannot be advantageously (and some not at all) 
 applied in the reduction of this metal. Where the proportion of sulphur is minute, it may be partly 
 volatilized by previous roasting, and partly taken up by excess of lime in the flux. By this last appli- 
 cation, the sulphur in the coke of some of the English furnaces is gotten rid of. The remarkable action 
 of sulphur upon iron-filings, when made with water into a paste, (which, after a while, develops 
 intense heat, and finally bursts forth in spontaneous flame,) belongs more properly to the formation o! 
 sulphuric acid, but may be mentioned, once for all, here. The influence of compounds of sulphur and 
 carbon together has not yet been satisfactorily studied. 
 
 As sulphur gives the property of red-shortness, so phosphorus seems to impart that of cold-shortness, 
 or brittleness at low temperatures, but not to an equally prejudicial extent. There is hardly any iron 
 in which a trace of this substance cannot be found. With bar-iron occurring in proportions as high as 
 \ per cent., it only hardens the metal without diminishing tenacity ; at J per cent, the tenacity is 
 seriously diminished ; and over 1 per cent, makes the iron of very bad quality and very limited use. 
 Phosphorus lessens the capacity for heat of the metal, and increases the facility with which bar-iron 
 can be welded. Crude iron it makes more fusible and retains longer melted, so that in minute propor- 
 tions it is rather an advantage for castings. Phosphorus appears capable of uniting with iron in all 
 proportions, but at a high temperature there is but one definite compound, consisting of 2 atoms of iron 
 and 1 of phosphorus, or iron 0176 -f- phosph. 0 224. The natural kingdom does not afford any pliosphu- 
 ret of iron, but phosphates are widely extended and numerous. Phosphorus is supposed to behave with 
 carburets of iron in a similar manner with sulphur, but, like this last, has not in this respect been studied. 
 
 The effect of acids, of whatever kind, upon iron, appears to depend upon the presence and decompo- 
 sition of water ; and hence, in an anhydrous or concentrated state, their action is uniformly more feeble 
 than when dilute. The presence of carbon, too, and its state of combination, also affect, and in their 
 proportion weaken, the influence of the acid. Thus steel is distinguishable from iron by the ease with 
 which it is attacked and stained by nitric acid, and white iron is more affected in this manner than steeL 
 Hard iron, in all conditions, is less easily attacked than soft ; and upon this, as well as the state ol 
 combined carbon, rests the art of damascening, or watering the surface of iron and steel. 
 
 Acetic acid acts readily upon iron and upon its peroxide, but slowly upon the protoxide. The acetate 
 of iron thus produced is used extensively in calico-printing, under the name of iron liquor. 
 
IRON. 
 
 79 
 
 Carbonic acid, without the presence of water, does not act at all on iron or its oxides, artificially, 
 though carbonates of iron form a very extensive and important class of minerals. The different sorts of 
 coloring-matter known as Prussian-blue, are carbo-azotic compounds, or hydrocyanates of iron, whose 
 practical use is better understood than their theoretical composition. (See Prussian Blue.) 
 
 Gallic acid, which is a compound of oxygen, hydrogen, and carbon, acts very feebly upon iron and its 
 protoxide, or, perhaps it may be said, not at all ; but upon the peroxide it acts energetically, striking 
 a deep, black, and permanent color, and constitutes, in fact, the basis of all ordinary black inks. 
 
 Hydrochloric acid acts with great readiness upon iron and its oxides. For all applications in the arts 
 where the object is to produce or remove oxidation, it is undoubtedly the best, though not the most 
 economical agent. Upon crude iron it is best to be employed concentrated. 
 
 Nitric acid, highly concentrated, has but a feeble action upon iron ; at its average concentration it 
 acts with great energy. On account of its peculiar behavior towards carburets of iron, it generally 
 enters as an ingredient in etching-liquors. Thus, for making damascene designs upon cutlery, Rinman 
 recommends a wash composed, by weight, of 4 nitric acid -f- '2 sal-ammoniac (hydrochlorate of amm.) 
 -f- 1 sulphate of copper -j- 72 water. Where the etching is required to be deep, as, for instance, in 
 mosaic damascening, where gold is to be inlaid, the nitric acid is inconvenient, in depositing a salt diffi- 
 cult to be cleaned out. 
 
 Phosphoric acid attacks iron with great avidity, but not its oxides at ordinary temperatures. The 
 artificial phosphates thus produced are without interest to the arts as yet ; the natural ones form an 
 extended mineral class. 
 
 Dilute sulphuric acid, as well as sulphurous acid, act upon iron at ordinary temperatures, and with 
 energy as the temperature, and to a certain extent the dilution, increase, forming, ultimately, sulphates 
 of iron. They also combine with the oxides of iron in various proportions. The crystallized sulphate 
 of the protoxide is known in commerce as green vitriol, or copperas. W T hen this is heated in close ves- 
 sels it parts with its water of crystallization, and upon continuance of the heat, after divers changes and 
 disengagements, becomes converted into pure peroxide of iron, which is the colcothar of commerce, or 
 the crocus martis of the old druggists, and the plate-powder or ronge of the silversmiths and polishers 
 of steel and speculum-metal. 
 
 Solutions of the alkalies or alkaline earths do not appear to act upon iron or its oxides. On the con- 
 trary, their presence seems rather to retard the decomposition of water. At a red heat iron will take 
 up about 10 per cent, of ammoniacal gas, becoming white and extremely brittle, but less liable to alter- 
 ation from air or moisture. At the same temperature, potassa and soda are deoxidized by malleable 
 iron ; if crude iron be fused with these alkalies, it parts progressively with all its carbon, and becomes 
 bar-iron. It has been generally supposed that the metallic bases of the alkalies do not combine with 
 iron, or rather, are sublimed at the temperature required for such alloy. But more recent observations 
 disaffirm this supposition. Potassium and sodium, for instance, can be combined synthetically with 
 iron, and magnesium and calcium are often found, though in minute proportions, in the crude iron of 
 commerce. How far they influence the character and quality of this metal is yet obscure. Karsten 
 observes that of potassium causes the alloy to be hard, and to be welded with difficulty, while 
 r _>__ of calcium is enough to impair materially the qualities of iron. Magnesium appears to be got rid 
 of entirely in the processes of refining and puddling. Barium no otherwise affects the metal than by 
 embarrassing the operations of the liigh-furnace, when present with the minerals there as sulphate of 
 baryta. 
 
 The earths, so called, : which need only be mentioned silica and alumina,) exercise, at ordinary 
 temperatures, or even at any temperature below fusion, no appreciable chemical action upon iron. 
 Associated with carbon, at this last temperature, they are reduced to their metallic bases, (either by the 
 iron or by 'the carbon,) which enter into combination with the iron, and modify it more or less. Sili- 
 cium is found more abundantly in gray iron than in white ; its maximum, as yet observed, may be 
 stated at 4£ per cent., including that which is found free in the condition of silica in the cavities of crude 
 iron. Its average hardly exceeds 1 per cent. There is no reason to suppose that this proportion affects 
 the quality of the metal ; on the contrary, it may be assumed not to interfere with, if it does not pro- 
 mote the fusibility and fitness for castings. The opinion among practical iron-workers (which is not, 
 however, partaken of by chemists generally) is, that a certain small proportion of silicium augments 
 tenacity. The operation of refining generally drives off 9-10ths of the silicium contained in the crude 
 metal ; but a proportion is often restored in subsequent processes, of which it would be well for man- 
 ufacturers to take account, in view of a particular quality that may be desired. Thus Boussingault 
 found bar-iron, melted in a Hessian crucible, to have taken up more than J,- per cent, of silicium. Syn- 
 thetic experiments in the small way warrant the belief that a smaller proportion than this hardens iron 
 and makes it less tenacious. Karsten presumes the action in this last respect of silicium to be more 
 injurious than that of phosphorus. Whether, as has been supposed, the conversion into steel is due to 
 silicious as well as to carbonized combinations, is not yet understood. No higher than a trace of alumi- 
 num has been observed either in crude or in malleable iron. Such traces are more distinctly marked 
 in gray than in white iron, and most distinct in cold-short iron. There can be no doubt that this base 
 injures the tenacity of the metal. Stodart and Faraday’s experiments upon the manufacture of icootz, 
 or Indian steel, (in which § per cent, of aluminum has been found, and which is considered to owe its 
 peculiar properties to the association,) will be spoken of under the article Steel. 
 
 Iron forms an alloy with most of the other metals in varying proportions, dependent chiefly upon 
 temperature. With antimony it has a great affinity, and associated with \ per cent, of this last, it be' 
 comes very brittle, either cold or hot. When united in the proportion of single atoms, (when the 
 antimony is 70 per cent, of the mass,) the elements are inseparable by the highest degree of heat. 
 
 Arsenic in the proportion of lA per cent, has been observed to destroy entirely the tenacity of iron 
 On account of the extreme volatility of this metal, it is difficult to effect directly so high a combination 
 There is no doubt that a very much smaller proportion acts injuriously. 
 
80 
 
 IRON. 
 
 Bismuth does not readily form an intimate union with iron. At the temperature of fusion of this last 
 a great part of the former is volatilized, and its effect seems more felt in the treatment than in the 
 quality produced ; of bismuth do not affect the strength or malleability of the metal. 
 
 Chrome unites with iron in all proportions, making alloys very hard, brittle, crystalline ; more brilliant 
 than iron, less fusible, much less magnetic, and much less oxidable. And these characters are more 
 marked as the proportion of chrome increases. An alloy containing 60 per cent, of chrome is very 
 fragile, whiter than platinum, and so hard that it scratches glass as deeply as a diamond. On the other 
 hand, from 1 to 2 per cent, of chrome hardens cast-steel, and gives it the property of damascening 
 beautifully, without diminishing its malleability. 
 
 Cobalt unites with iron in all proportions and without altering its properties, at least until the quantity 
 of the former becomes considerable. 
 
 Copper can hardly be said to make a true alloy with iron, though when fused together a small pro- 
 portion of the former will be taken up and retained upon subsequent fusion. Of crude iron it increases 
 the tenacity when in the proportion of 1 or 2 per cent., and it might, therefore, be advantageously and 
 economically employed for certain castings. As much as \ per cent, in bar-iron injures its capacity for 
 being welded ; a larger proportion makes a metal brittle at a red heat. 
 
 Gold may be alloyed in all proportions with iron, for which it has a remarkable affinity, and to which 
 it imparts no new quality until its own quantity becomes considerable. When the gold is from 20 to 
 25 per cent, of the mass, the alloy is silvery and very hard, so much so that cutting tools may be made 
 of it. On the other hand, when the iron is from 15 to 20 per cent, (to be classed more properly as an 
 alloy of gold) it makes what the jewellers know as gray gold , of late much used for little trinkets, and 
 admired for the beautiful polish that can be given it. Gold is also used as a solder for delicate 
 steel-work. 
 
 Lead does not form an alloy with iron directly, with crude iron not at all, and with bar-iron, treated 
 with litharge, in proportion not exceeding 2 per cent. This (and even a smaller proportion) renders the 
 mass more brittle and more fusible. The ores of lead, which are sometimes found associated with those 
 of iron, and have to be treated together in the high-fumace, are reduced, but the metallic lead lies in the 
 hearth without uniting with the iron. It is sometimes found there when a furnace is blown out, not only 
 in this state, but also as red-oxide or minium , and as a crystallized silicate. 
 
 Manganese, on the contrary, has a remarkable affinity for iron, and of all the metals is found most 
 frequently in association with it. In small proportions the manganese renders the alloy harder, without 
 impairing its tenacity ; the limit in this respect is not ascertained, but it may be safely assumed at 1 J 
 per cent. The addition of manganese diminishes the fusibility of iron, but increases its oxidability. 
 Alloys of these metals almost always exhale an odor of hydrogen upon being breathed on, and this 
 greed of manganese for oxygen is one of the means by which the crude iron from manganesian iron-ores 
 may be refined, so as to part with nearly or quite all of its alloy. The tendency of such manganesian 
 ores to yield a metal easdy convertible into steel has caused them to acquire the name of steel-ores with 
 some persons. But this tendency, as well as the uniform liability of such ores (unless treated suitably) 
 to give a white iron in the high-furnace, does not appear to arise directly from the manganese, but indi- 
 rectly only, from the influence which this last has upon the behavior of carbon. 
 
 Molybdenum, like tungsten, unites with iron in moderate proportions, without altering its qualities, 
 further than augmenting its hardness. An alloy of l-5th molybdenum in iron is fusible, extremely hard, 
 with small resistance to impact, but tenacious in other respects. 
 
 Nickel behaves with iron very much like cobalt, especially in the white color it gives, and in the 
 facility and variety of its combinations. An alloy of 1 atom of nickel to 12 atoms of iron, (which cor- 
 responds to about 8 J per cent, of the former,) is one often met with in nature, under the name of meteoric 
 iron. This is less oxidable and less ductile than iron unalloyed, but in other respects the metal is of 
 good quality. Not to speak of the sword of Alexander, which is said to have been made of an alloy 
 like this, nor of the sabres of Jehanguire, fabricated of a similar metal some 2000 years later, the sword 
 presented to Bolivar in 1821 was forged of the meteoric iron of Santa Rosa, near Santa Fe de Bogota, 
 whose atomic constitution is almost precisely what has been given above. 
 
 Palladium renders iron brittle when in even moderate proportions ; when the proportion is small, it 
 induces no further alteration than increased hardness. The same affinities and effects belong to alloys 
 with rhodium, iridium, and osmium. A proportion of 3 per cent, of either of these in bar-iron prevents 
 rusting, and renders the alloy capable of being tempered like steel. It is with steel, however, that the 
 alloys of all these metals are the most remarkable. The same may be said, too, of platinum, whose 
 alloys with steel are of great interest, and present some remarkable peculiarities, but which hardly 
 unites directly with iron, except in the presence of carbon. 
 
 Silver does not form a real alloy with iron. Fused together, the iron will take up a small proportion 
 of the other ; which, when it is as low as only, injures the malleability and weldability of the 
 
 mass. In these effects, Karsten ranks it as very nearly equivalent to sulphur. 
 
 Tantalium does not unite with iron directly; except at a very high temperature, and in the presence 
 of carbon. So formed, it is tenacious, without ductility, and readily scratches glass. 
 
 Tin and iron have a great affinity for each other ; unite in all proportions, and at last so permanently 
 as not to be separated by fusion. The alloys in which tin predominates are without the peculiar char- 
 acters of this metal, while they have gained none of the properties of iron ; and the same may be said 
 when the proportions are reversed. This does not apply at all to that superficial alloy which takes 
 place in what is known as the tinning of iron, and which is manifested both with crude and malleable 
 iron. The particulars of this art will be given under the article Tin-ware. 
 
 The alloy of titanium will be spoken of in connection with the so-called titaniated iron-ores. 
 
 Tungsten behaves like molybdenum ; and its principal effect is to increase the hardness of the alloy. 
 Even when the tungsten is 37 per cent, (which is equivalent to 1 atom of tungsten to 6 of iron,) the 
 physical characters of the alloy are very much those of white iron. 
 
IRON. 
 
 81 
 
 When zinc is kept in fusion in iron vessels, it gradually corrodes and dissolves them ; a proof of the 
 capacity of these metals to form alloys. At the high temperature, however, required for the fusion of 
 iron, the zinc is volatilized ; and so is never found, even in trace, in the metal from high-furnaces where 
 iron-ores containing zinc are used. It is the opposite when the ores used for the extraction of zinc con- 
 tain iron ; this last is very hard to be gotten rid of, and even in small proportions injures the mallea- 
 bility and embarrasses the lamination of zinc. There is also a superficial alloy, like that mentioned just 
 now in the case of tin , which is produced when clean sheets of iron are plunged in a bath of melted 
 zinc. The preparation of this zincked iron, known in commerce as galvanized iron , is a late application 
 of art, which will be particularly described under Zinc. 
 
 Iron is one of the few metals which do not form an amalgam with mercury directly. It is possible 
 by the medium of a third metal, as zinc or tin, to produce indirectly amalgams which are of no interest 
 in the arts. 
 
 Mineral characters and geological occurrence of productive ores of iron. — 1. Native iron, bolide, 
 meteoric iron, d'c . — Although these are not strictly ores of iron, yet, as they are both workable and pro- 
 ductive when they occur, it is proper to include them here. The means of distinguishing with certainty 
 those which are terrene from those which are formed in, or at least fall from, the atmosphere, are yet 
 so vague, that the two classes are here counted together. The occurrence of nickel is generally held to 
 mark a meteoric origin. The most remarkable specimens are those of Siberia, discovered by Pallas ; 
 of Louisiana, sent to New York by Gibbs; and of Buenos Ayres, found by Rubin de Celis. This last 
 more than doubles the size of any of the others ; weighing about fifteen tons. Besides these, Africa, 
 near the Cape of Good Hope ; North America, at Canaan in Connecticut, and Randolph County, North 
 Carolina, and in Bedford County, Pennsylvania ; South America, along the eastern cordillera of the 
 Andes, and in Brazil, and Peru; Asia, in Hindostan; Europe, from Bohemia, Croatia, France, Italy, 
 Saxony, and Switzerland ; and the Esquimaux settlements near Davis’ Straits, (which belbng to no con- 
 tinent,) have all contributed specimens. The color of these varies from silvery to bluish white ; their 
 hardness may be taken at between 4 and 4'5 of Kirwan’s scale ; they are all magnetic. Their specific 
 gravity varies from 5'95 to P34-, according to the associations, which are principally, and sometimes 
 wholly, nickel, apparently in definite proportions. Arsenic, chrome, cobalt, copper, and molybdenum 
 have also been found united with the iron, as well as a small proportion of carbon in the shape of 
 graphite. 
 
 2. Magnetic iron-ore, octahedral iron-ore, fer oxidule, black oxide of iron, loadstone, dec. — This is the 
 only ore of iron acted on by the magnet without application of heat, except the titaniferous iron grains 
 of Brazil. Its geological occurrence is in primary formations ; and it is apt to be accompanied with 
 quartz, horublend, calcareous and fluor spars, and asbestos, which modify variously its fusibility and 
 workable properties. Its chief deposits are in Sweden and Norway, and in Siberia, where it occurs in 
 bands; sometimes it is found in beds, as in Savoy and Piedmont, Tyrol and the Vosges; it forms the 
 mass of considerable mountains, as at Taberg in Smoland ; and is also worked, as in Naples, in small 
 grains like sand. In the New World it is found also, as in La Plata, Brazil, Mexico, and the United 
 States ; but generally not in sufficient extent to work. The mines at Schooley’s Mountain, in New Jer- 
 sey, have been, it is believed, abandoned ; and the new works for this ore near Sykesville, in Maryland, 
 have not been long enough in operation to determine their reliability. This ore frequently occurs in 
 crystals, whose primary form is the regular octahedron, and whose cleavage is perfect. Its color is 
 black ; its lustre generally metallic ; its fracture generally conchoidal ; its hardness 5'5 to 6’5 ; its spe- 
 cific gravity 5 at a mean. When pure, it is composed of 1 atom of iron and 1 J atoms of oxygen. The 
 metal from this ore, known as Swedish iron, is of the best quality in commerce : and its properties, 
 although attributed sometimes to the methods of its treatment, are probably more owing to the 
 materials. 
 
 3. Specular oxide, an hydrous peroxide of iron, iron-glance, red hematite, fer oligiste, eisenrahm, dec . — 
 This mineral is generally found in primary formations, but occurs also among sedimentary rocks. Va- 
 rieties of the species, apparently of daily formation, are to be met with amid the lava of Vesuvius, and 
 in ancient and existing solfaterras, as of Tolfa and Guadaloupe. The most celebrated deposit of it is in 
 the island of Elba, where it has been worked for more than 2000 years, and where the extent of the 
 excavations and deblais attests the industry more than the skill of the ancient miners. The Elba mines 
 are continuations, probably, of the Tuscan ores. At present there are three workings in a hill of about 
 three miles in extent, and elevated only about 600 feet above the sea. The rock in which it occurs is 
 a whitish talcose slate, called there bianclietta, easily worked, but, after all, not very productive in 
 modern times; the whole quantity exported not long since, being not more than 15,000 tons. The ore 
 here is often slightly magnetic, and contains, in fact, an admixture of magnetic oxide, and often titanium. 
 The wash from the actual workings, presenting the ore in the shape of octahedral grains like sand, is 
 also exported under the name of poulette. The same granular occurrence is met with at Framont in 
 the Vosges, the only point at present in France furnishing specular oxide. There are some other strik- 
 ing localities, such as Gellwara in Lapland, and Sommorostro in Biscay, (where it forms the mass 
 of large mountains,) Norberg in Denmark, and the Minas Gerues in Brazil, where it exists in very ex- 
 tensive beds. The crystals of this ore are varied ; but the primary form appears to be a rhomboliedron 
 nearly cubic. Its color is a brilliant black, very often iridescent, with a metallic lustre. Its fracture is 
 sometimes lamellar, but more generally irregular. Thin laminae show a deep blood-red color. Hard- 
 Dess, from 5-5 to 6’5 ; magnetism, when it exists, attributable to admixture of magnetic oxide ; and 
 specific gravity at a mean, 5-10. When pure, it is entirely a peroxide of iron, and consists of 1 atom of 
 iron with 14 of oxygen. The metal from this ore may be taken as equal to that from the former class ; 
 the Celtiberian iron of old time, and the Bilboa blades of more recent periods, were made w 7 ith it; and 
 in Sweden even, in many mines, it is not separated from the magnetic ore. The micaceous variety 
 crystallizes in hexagonal tables, which are divisible into thin translucent plates. Its powder is a bright 
 red- its specific gravity about 5'25. This is found of extreme beauty near Northampton in Massachu 
 
IRON. 
 
 85S 
 
 setts. Red hematite occurs massive, stalactitic or fibrous, and mamelonated. Its color is a dark red, 
 with very often a metallic lustre and aspect. Hardness, about 7 ; powder, which is red, never mag- 
 netic; and specific gravity, at a mean, 5. Thomson gives the specific gravity of a specimen from 
 Muirkirk at 6 p 305. It is often mixed with oxide of manganese, and is then a reddish-brown, almost 
 black. Of this variety are the deposits in Cumberland, (Eng.,) so useful in admixture with the ores ol 
 Wales; and in this also is the principal mining about Lauterberg and Altenau in the Hartz. This is 
 the bloodstone of the metal-polishers. The compact red iron-ore of Lavoulte, in France, occurs roassi’-e, 
 in veins 50 to 60 feet thick. It is also sometimes found in pseudo-morphous cubic crystals-. Its color 
 is a brownish-red ; its fracture uneven ; its specific gravity about 4’25. Red ochre, which is chiefly usul 
 as a pigment, but also as an ore, may be regarded as closely allied to this last variety, in which it is 
 principally distinguishable by a softer texture and more lively red color. 
 
 All these classes of ores, when pure, contain the iron associated only with oxygen. 'The others 
 which follow contain also water as a permanent additional element, in the proportion of from 10 to 15 
 per cent. Such are, 
 
 4. Hydrated peroxide of iron, fibrous and compact brown hematite, brovm ochre, umber, cetites, limo- 
 nite, bog-iron ore, dec., dec. — This class is very extensive, and is found as well in primary formations as 
 in newer rocks. Its principal deposits are in the oolite series and chalk equivalents. Bog-ore is con- 
 sidered of daily formation. It is sometimes found in octahedral and cubic crystals, but most generally 
 massive. The color of the mass is in various shades of brown, but its powder and streak always yel- 
 low. Its hardness is from 4-5 to 5 ; its specific gravity, at a mean, 4. It does not act on the magnet. 
 Chemically, it is composed of 1 atom of water, 1 of iron, and 1 J of oxygen ; or otherwise, 1 atom of 
 pure specular oxide with 1 atom of water. From this class (principally, the compact brown hematite) 
 comes a great part of the iron of France ; the deposits about Whitehaven in England, which are of 
 enormous extent, are a variety (the reniform) of it ; the oolitic ores, which are small globules held to- 
 gether by a calcareous or argillaceous cement, cover a considerable extent in Burgundy and Lorraine, 
 and occur also in Carinthia and Styria; the granular hydrates, or ferriferous sand, are worked in Nor- 
 mandy and other parts of France, in Switzerland, in Silesia, Bavaria, and Poland ; and, finally, the bog- 
 ores are profitably mixed with other ores in many places, as in Silesia and Livonia, and in the coal 
 region of Maryland, or worked alone as in the last-named state. Phosphate of iron, however, which 
 occurs frequently in this alluvial variety, prejudices its unmixed use. Brown ochre is principally used 
 as a pigment ; and the cetites, or eagle stones as they are called, which occur along the Rhine, are almost 
 as much used by the French shepherds as amulets, to be hung around the neck of a favorite ram, as 
 for any other purpose. The metal from this variety, however, as well as from fhe whole class, is unex- 
 ceptionable whenever (as is the case generally, except with the bog-ores,) there is no adventitious im- 
 purities or associations, in sufficient proportion to be injurious. Ordinarily, the associations are from 
 three to ten per cent, of silica, alumina, and manganese, in nearly equal quantities ; amounts which in 
 nowise embarrass the smelting or the result. 
 
 5. Carbonate of iron, brown spar, argillaceous iron-ore, spathose or sparry iron, spherosiderite, fir 
 spathique, fer carbonate lithoide, stahlstein, dec. — Under these synonyms and varieties may be included 
 a class more widely extended and more productive than any other on earth. Two principal divisions 
 may be made of it— the crystalline or sparry, and the compact or litho'id — the former occurring in beds 
 and pockets in the primary rocks, the latter belonging to newer formations, and especially stratified 
 among the coal-measures. The facility with which the former can be reduced rendered it of abundant 
 introduction into the smelting-houses of the ancients ; it was from this ore that the Styrian works turned 
 out the metal so favorably known before our era as the Norican non ; and the name of steel-ore, under 
 which it has been designated, from the readiness with which it yields a steel at the first treatment, is 
 not less a test of its appreciation. This variety is both massive and crystallized. In the latter case, its 
 primary form is an obtuse rhombofcedron, nearly approaching the form of calcareous spar. Its deriva- 
 tives are more complex ; but not unfrequently it is converted, as in the very large Cornish crystals, into 
 regular six-sided prisms. Its color is gray of various shades, yellowish and greenish, but sometimes 
 almost red. Fracture is imperfect chonchoidal, with a vitreous and somewhat pearly lustre. Thin 
 fragments are often translucent. Its average hardness is about 4; its specific gravity, at a mean, 375. 
 It is not magnetic. Abstraction made of the impurities, which are generally carbonates of lime and 
 magnesia, this mineral is composed of 1 atom carbonic acid and 1 atom protoxide of iron. The compact 
 or litho'id variety occurs in nodules and in regular veins or strata ; this last is especially the case in the 
 coal-meilsures, with which it is always more or less associated. Its color is a dark gray, and when the 
 allied carbonaceous matter is abundant, almost black. Its specific gravity is from 3 to 3’5. Its com- 
 position is the same essentially as that of the other variety, but with the uniform addition of notable 
 proportions of silica and alumina, and coaly matter ; protoxide of manganese is very often found with 
 it and in the coal-measures, sulphur but in small quantities. The value of this ore is more in the facility 
 with which it is treated than the quantity or quality of the metal produced. When in an unaltered 
 state, it rarely yields more than 33 per cent, of metallic iron; the altered carbonates, which occur most 
 generally in accidental beds among the primary rocks, may give 45 per cent. MuslieVs black band, as 
 it is termed, a seam of high reputation near Airdrie, in the Glasgow coal-field, returns about 41 per 
 cent. Even when made with charcoal, the iron from this ore is inferior in its physical properties to the 
 Swedish, to the Spanish, and to the Styrian iron, and, in general, to the metal produced from any of 
 the preceding classes ; when coke or coal is used its inferiority is, of course, more strongly marked. 
 Yet improvements in the methods of manufacture have gradually cured these natural disadvantages to 
 an extent which, though it still leaves something to desire, is yet sufficient for most practical purposes, 
 and may well be balanced by the economy of production and the cheapness of the metal furnished. 
 Indeed, without the use of coal and the association of this ore with the beds of fuel for smelting it, some 
 of the most important contributions to the civilization of the present day would have been either im- 
 possible, or at least unattempted. From this last variety comes now nearly the whole enormous prod- 
 
IRON. 
 
 S3 
 
 net in iron of Great Britain ; is is being extensively used in France, where, as in the departments o! 
 the Nord, Loire, and Allier, it exists in abundance ; it returns a part of the metal from the Hartz ; it 
 was the earliest worked of the iron-ores of America along the Atlantic coast, when, as little more than 
 a century since, it was seriously looked to as an available resource for the supply of crude iron for the 
 English market, and, worked with charcoal at many points, still continues to yield a profitable return ; 
 and finally, when foreign competition is, for an interval only, set aside or guarded against, will enable 
 the bituminous coal-fields of Maryland, Pennsylvania, Ohio, and Virginia to supply the entire consump- 
 tion in iron of the whole American continent. 
 
 Such are the principal classes of available ores of iron. Mineralogists, and metallurgists even, often 
 extend their number to include others, which should be, in theory, and sometimes may be in practice, used 
 to advantage. So the silicated iron-ore of Kupferrath, the chamoisite of the Valais, the garnets of Henne- 
 berg, the titaniated ore of Maryland, are actually smelted ; while the volcanic basalt of France, Ger- 
 many, and Ireland, and the jasper of Piedmont and Siberia, contain iron enough to render its extraction 
 hopeful. So the franklinite of New Jersey, which contains 46 per cent, of metallic iron, might be sup- 
 posed as proper for the domain of the iron-master ; but in fact, it has only been employed, hitherto, (as 
 twelve years ago for the weights and measures of the United States,) in the fabrication of brass, and 
 probably will ever continue to be invoked solely to surrender its zinc. As for the other mineral combi- 
 nations in which iron is found — the arseniets, chromates, columbates, phosphates, and sulphurets, &c . — 
 they may be omitted here. Some (as, for instance, the chromates ) are worked for and applied to pur- 
 poses in the arts other than the reduction of the iron they contain ; others (as, for instance, the phos- 
 phates) yield an iron of such inferior quality, when treated alone, as not to be of desirable employment; 
 while others, (as the sulphurets, <fcc.,) even were there no objection on this last score, require such ex- 
 pensive processes to effect a separation, as to be quite useless as ores of iron. The following table is 
 of interest, as showing the normal proportion of metallic iron existing in the types of the classes arid 
 varieties that have been mentioned : 
 
 Class. 
 
 Variety. 
 
 Iron per 100 parts. 
 
 1. Native or meteoric iron 
 
 2. Magnetic iron-ore 
 
 S. Specular iron-ore 
 
 4. Brown hematite 
 
 5. Carbonate of iron 
 
 In purity 
 
 Mean of seven analyses 
 
 In purity 
 
 Red hematite 
 
 Compact red iron-ore ... 
 
 Red ochre 
 
 Compact 
 
 Fibrous 
 
 CEtites 
 
 Oolitic 
 
 Granular 
 
 Brown ochre 
 
 Bog-iron ore 
 
 Sparry 
 
 Lit.hoi'd ; altered 
 
 94- 
 
 12-40 
 
 67-47 
 
 70- 
 
 67-67 
 
 56-50 
 
 40-53 
 
 59-18 
 
 56-98 
 
 54-97 
 
 44-45 
 
 42-21 
 
 45'85 
 
 29-54 
 
 44-91 
 
 40-79 
 
 33-54 
 
 Metallurgic treatment of iron. — Under this head belong the smelting of the ores to produce crude 
 iron ; the founding or remelting of that product when required to be in certain forms and of metal 
 properly termed cast-iron ; the refining of crude or cast-iron, and its forging, so as to give malleable or 
 6ar-iron ; and, finally, the operation, by hand, upon comparatively small masses of bar-iron, known as 
 smith's work. For the first of these processes is required a furnace ; for the second, a foundry.; for 
 the third, a forge, or rolling-mill ; and for the fourth, a smithy. Under this last denomination will be 
 included as well the manipulations — which, from the color of the work turned out, (and perhaps, also, 
 from the soiled externals of the workmen,) are ordinarily termed Mac/rsmithing — as the operations 
 with the lathe, die., which are demanded in what is technically termed a finishing- shop. 
 
 1. Smelting. — This is, both in theory and in fact, a chemical operation : depending, first, upon the 
 tendency of most earthy and metallic substances to melt by heat; next, upon the affinities of the ma- 
 terials usually put in furnaces for new combinations, while in a state of fusion ; and then, upon the 
 excessive gravity of metallic iron, which, in this state, tends to make it separate from and sink through 
 the melted mass. In this last regard, it may be said, that while the specific gravity of all the other 
 solid materials likely to come together in smelting (even in a coal or coke furnace) is not much more 
 than twice that of water, the specific gravity of metallic iron is seven times as great, and its gravitating 
 tendency is, therefore, at least three times that of any other element. In charcoal furnaces, this average 
 tendency downwards is still greater. The following paradigm, in which only the chief materials and 
 products in smelting are shown, will serve t< illustrate the character of the affinities that are exercised 
 and the recompositions that result : 
 
IRON. 
 
 
 MATERIALS. 
 
 Gaseous Atmospheric Air... \ ^7" en " 
 
 1 ( JN itrogen 
 
 Solid 
 
 'Iron ore - 
 
 Fuel. 
 
 r Oxygen 
 
 Carbon 
 
 Iron 
 
 Silica 
 
 Alumina, <irc.. 
 
 'Oxygen 
 
 Hydrogen 
 
 Nitrogen 
 
 Carbon........ 
 
 Silica 
 
 [ Alumina, ifcc. . 
 
 f Oxygen 
 
 Carbon 
 
 Alkaline Flux 3 Lime 
 
 I Silica 
 
 (_ Alumina, <fec. . 
 
 Carbonic Acid. 
 Gaseous. 
 
 Crude Iron. Furnace Cinder. 
 Solid. Solid. 
 
 The success of these results depends upon the means employed. Thus, it is well known that, with 
 fuel enough and air enough, heat can be generated sufficient, both in intensity and abundance, to fuse 
 the most refractory and voluminous materials. But as both air and fuel are costly in their supply, the 
 task of the furnace-manager is so to admix his ores and fluxes as that their simultaneous fusion shall 
 take place at the lowest possible temperature ; that it shall be the most perfect, to allow the utmost 
 chance for the entire separation and descent of the melted metal ; and that on its continuance, and by 
 the presence of substances suitable for taking up and neutralizing all accidental or necessary impurities, 
 either in the ores, fuel, or flux, there should be the least possible opportunity for the iron, after separa- 
 tion, to enter into new and detrimental combinations. All this was expressed long ago, with great 
 practical terseness and almost sufficiently comprehensive caution, by Rogur, the Welch founder, in 
 saying that “ In order to make iron, you must first make glass.” It is to produce this glassy cinder 
 out of all the solid materials in the furnace, (except the irca,) that the founder aims ; it is by this cin- 
 der that, from hour to hour, he judges how his furnace wo-ks. In earlier times, and with many still, 
 this task was matter of routine, or of tact, which habits of observation had rendered almost intuitive. 
 At the present day such tact can be guided and helped by accurate theory, which, upon a nearly per- 
 fect knowledge of how different chemical elements behave towards one another, can calculate arith- 
 metically the dimensions of the furnace and the proportions of ingredients proper to a given result 
 This will be better understood after some details upon the construction of the furnaces themselves, and 
 description of their parts. 
 
 Figs. 2331 and 2332 are respectively a section and ground- 
 plan of the hearths, or furnaces, in use about the middle of the 
 sixteenth century, as described by Agricola. The letter h, in 
 both, shows the hearth proper ; t, the tuyfere ; and b, the bel- 
 lows. This form is not unlike the blacksmith’s hearth of our 
 own times ; and has, in fact, been perpetuated, with but small 
 modification, in the Catalan forges of the present day, where 
 a malleable iron is produced from suitable ore by the first 
 process. More refractory ores were treated in crucibles (as it 
 were) of a somewhat different shape, a9 under ; where Fig. 
 
 2333 is a ground-plan, and Fig. 2334 a section through x y of that plan. The same scale answers for 
 all four figures. 
 
 Both of these constructions belonged to a period when iron, more or less malleable, (an object ol 
 earlier utility in the arts than crude iron,) was produced direct from ores whose choice and value 
 depended then greatly upon such a property. And both are of the kind which the Germans call 
 ttuck-ofen, and the French fourneaux it masse, (in English, pot furnaces ) — such as until very recentlv, 
 tnd still, indeed, are used in Hungary, Carinthia, Styria, and along the Pyrenees. Both furnish the 
 reduced metal in a solid lump, loupe , stuck, or salamander, which has to be lilted by main force out of 
 
IRON. 
 
 the hearth — the fires, of course, being suffered to go down for the purpose. The second kind appears to 
 have had, like the modern stiick-ofen, a tap-hole for cinder or slag to be removed. The stiick-ofen, used 
 at present in what was formerly the principality of Henneberg, are shaped internally 
 like the adjoining Fig. 2335. They are from seven to ten feet high, built of sand- 
 stone ; but the crucible proper, c, is of cast-iron. There are two openings : one at t, 
 where is the tuyere ; the other in front, for working — i. e., removing the cinder and 
 the metal. The cinder is always running out ; the metal is kept in (it is never very 
 liquid) by a temporary wall of brick, which is taken down when the stuck is drawn. 
 
 In older times, the lov.pe, which weighs from 500 to 800 lbs., and which was formed 
 in six or eight hours, was drawn every day. The improvement of deepening the * 
 hearth left room for several loupes, which were separated in the workings by dry 
 charges of fuel only, and were removed every Saturday evening. At present, the 
 loupes, separated as before, are drawn whenever the hearth becomes full, but with- 
 out emptying the furnace, which continues in blast several weeks. 
 
 These Henneberg furnaces are types of an improvement which was beginning in the time of Agricola 
 and is known in Germany as the fluss-ofen — in France, as fourneaux a manche — in England, as tap 
 furnaces. The aim of this was to let the metal run out as well as the cinder; and the method of 
 attaining the aim was a contraction of the crucible proper, whereby the heat became more intense and 
 the metal more liquid. The stiick-ofen — which, to be sure, always yields an excellent quality of metal 
 — is very expensive, both in ore and in fuel : the low temperature it affords is not sufficient for the 
 reduction and subsequent combination of divers impurities (such as manganese, silicium, <fec.) in the ore, 
 so that the iron is left comparatively pure ; and as the slag contains ordinarily aoout 40 per cent, of 
 metallic iron, the metal, which sinks down on the hearth after having been enveloped in this slag, be- 
 comes also partially decarbureted, and is, in fact, a mixture of crude iron, malleable iron, and steel. 
 The fluss-ofen rendered the greater part of it crude iron ; and is, therefore, the germ of the modern 
 high-furnace. In its actual state, and like the Henneberg furnaces, only higher, (from 20 to 35 feet,) 
 the fluss-ofen continues in use to this day in various parts of Germany, and in some places of Sweden. 
 Tire Swedish furnaces were, indeed, until recently, all properly fluss-ofen. Since the intervention of 
 Berzelius, they conform more to the models generally followed in other parts of Europe and America. 
 
 The following figures will serve to show the probable march of improvement, as longer observation, 
 and greater range of materials that might yield iron, suggested the successive steps. For greater gen- 
 
 2335. 
 
 eraflty and simplicity, these figures show only the cuvette or inside section of the furnace, which neces- 
 sarily regulates the externals. Thus, there is no doubt that the earliest shape was the prism, or 
 cylinder, shown at Fig.. 2336, which we know to have been in use in the time of Agricola. As it would 
 soon be observed that, with such a shape, the materials were too heavily pressed below to allow free 
 passage for the blast, relief in this respect would be sought by battering the sides inwards, as shown in 
 Fig. 2387 ; while as, upon experience, it could not fail to be noticed that, if the materials, in descend- 
 ing, had more room, they would spread more easily — on this account the shape of Fig. 2338 might be 
 preferred. The suitability of one or other of these forms would be regulated by the less or greater 
 fusibility of the materials. But for average fusibility, as well as to combine the greatest advantage of 
 these two experimental principles, the form of Fig. 2339 would be seen to be the best ; while a slight 
 alteration of this, and a combination, in fact, of all previously known forms, brings us to the form of 
 Fig. 2340, which is exactly the modified fluss-ofen of Henneberg, before described. If tl e angles of 
 
 Fig. 2840 be rounded off, either designedly or by the degradations consequent upon its use, it will 
 assume the form of Fig. 2341 which is that of the ordinary fluss-ofen of Europe. Fig. 2342 is a modi- 
 fication of Fig. 2339, bringing the belly, or widest part of the cuvette, nearer to the blast, as would be 
 
86 
 
 IRON. 
 
 found desirable for less fusible ores ; while for those more refractory, a general narrowing, as in Fig. 
 2343, would be resorted to. Finally, as the use of earthy ores became prevalent, it was found better 
 to bring the top of the boshes (in German, biischung, a talus, or slope) nearer to the tuybre, and to narrow 
 the crucible below, as shown in Figs. 234-4 and 2345, which are tire types of the modern high-furnace. 
 In both these figures, h shows tire crucible, c r hearth, and b the boshes. The slope of these last is 
 more or less steep according to the fusibility of the materials, and their less or greater fragility under 
 pressure of a superincumbent. In this last regard, the height of the furnace-stack is an element in the 
 calculation ; although, for the generality intended to be illustrated by the figures, as well as for the 
 distinction between different kinds of furnaces, the height is immaterial. It is usual to call, now, every 
 thing above 27 feet a high-f urnace ; although, in the method of treatment, as well as in the character 
 of metal produced, it may be, as in parts of Germany and France, a fluss-ofen, and although it may 
 have no hearth proper, as in many places in Sweden. The different shape of the in-walls — straight in 
 Fig. 2344, curved in Fig. 2345, of either of which many examples are found— arises more from caprice 
 than from any logical conclusion. The latter is more retentive of heat, but more embarrassing to the 
 blast ; in the latter, therefore, the different stages of the process will be more distinctly marked than in 
 the former. If the object be to gather combustible gases at the trundle-head, (as in the method ot 
 Faber-Dufaure,) the shape of Fig. 2345 is preferable. 
 
 In some localities, the furnace is built upon the flat, and a veritable bridge connects with the hill. In 
 places where there are no hills — as in Staffordshire, for instance — a long ramp is constructed, either ol 
 earth or carpentry, along whose inclined plane the materials are carried up by suitable machinery. 
 
 Figs. 2346 and 2347 are a section, parallel to the front, and a ground-plan of a blast-furnace, which 
 may be taken as a type for all, whatever may be the materials employed. In these figures, h is the 
 
 crucible, or hearth ; t, t', indicate the passages and tuyeres (pronounced tweers) for the blast. In F.g 
 2346, b shows the boshes , a term applied as well to the space where the letter is as to the stones which 
 inclose it ; s is the general mass of masonry, called the stack ; i are the in-walls, of refractory materials, 
 (stone or fire-brick,) defining the cuvette ; l is the lining, of broken stone, pounded cinder, <tc., loosely 
 interposed between the in-walls, to allow them to expand without thrusting more than can be helped 
 against the stack, and also helping as non-conductors of the heat ; and ff indicate the ties, of bar-iron, 
 which run quadrangularly through the mass of the stack to secure it still further. In-walls are some- 
 times made double, with a void space between them. It is obvious that, within the limits of their gen- 
 eral aim, the particular dispositions of these are at discretion. A chimney, generally of brick-work, is 
 shown at c. On Fig. 2347, p p indicate the piers, connected by arch- work, for supporting the stack 
 vertically. These piers are generally themselves still further pierced with low and narrow archways, 
 (as shown by the dotted fines on the northeast pier,) to allow of readier communication between the 
 tuyere-arches, ttt, where the blast-pipes are. The arch T, in front, where the working is done, is 
 termed the tymp-arch — generally larger than the tuyere-arches. This plan shows three tuyeres, which 
 is an establishment for a furnace of the largest class; yet very many have but two, and smaller ones 
 are worked with but one tuyere. 
 
 Fig. 2348 gives an enlarged view of the disposition of the hearth ana boshes. Here, besides the parts 
 alrea'dy indicated by letters before used, s shows one of the cast-iron girders, or sows, for supporting the 
 thrust of tire arch ; y is the tymp-stone, protected by a casting called the tymp-plate, ( tymp , in Welch, 
 means a delivery, and hence is applied to the place where the product of the furnace is brought forth,) 
 both from the iron ringards, or long crow-bars, of the workmen, and Irorn the adhesion of the cindei, 
 which is very strong to heated stone ; and d is the dam- stone, protected, for similar reasons, by a casting 
 called the dam-plate ; h shows here the hearth-stone, or sole, which is a single, large, refractory stone, 
 and ought to underlie, in part, the dam-stone. This hearth-stone ought to have a fall of at least ^ inch 
 
IRON. 
 
 87 
 
 2348. 
 
 to the foot, towards the front, to assist the tymp of the metal, which comes out through a shoulder cut 
 in the lower face of the dam-stone. The cinder pours over the top of this last, 'llie place for the 
 tuybre, which was first a square opening left in the masonry, is 
 generally filled up now (since the use of hot air especially) with a 
 double hollow cone, called a water-tuyere, made of wrought-iron, of 
 Wrought- iron with a mixture of copper, or of cast-iron, and built in 
 with fire-clay on the tuyere-shelf. Fig. 2349 is intended to show this 
 utensil. The openings at a a are intended, the one to admit, the other to 
 let out, the water which circulates in the tuyfere, and preserves it from 
 the action of the heat in the 
 hearth. 2349 - 
 
 After stating the general prin- 
 ciple that the hearth and boshes 
 should be of the most refractory 
 material possible, the choice of 
 that material, of its position and 
 treatment, it is obvious, depends, 
 within certain limits, upon cir- 
 cumstances. Thus, they are built 
 of sandstone, dressed or undressed ; of soapstone ; of fire-brick ; or of an artificial puzzolana of cinder 
 and fire-clay. The joints are always laid in fire-clay, worked up into the consistence of mortar. 
 
 Having now the nomenclature of the principal parts, some precautions as to their dispositions, and 
 some requisites as to their proportions, may next be stated. The first thing after a secure, is a dry 
 foundation, particularly in the vicinity of the hearth ; and, therefore, too much provision of drains, active 
 enough to take off promptly all possible moisture, can hardly be made. Under the hearth-stone should 
 be constructed a false-bottom, with pieces of brick or stone, so as to avail of the non-conducting power 
 of air. But currents through this are to be avoided. In some places in Sweden, it is, to be sure, the 
 practice still to provide means for passing water under the bed of the hearth-stone, with the view of 
 increasing its duration. But such a practice cannot be approved on any score. 
 
 The plan of the hearth is square, oblong, or circular, or elliptic. The two last forms agree best with 
 theory ; the others are more convenient in construction. With three tuyeres, an oblong hearth is neces- 
 sary, on account of the less resistance opposite to the third tuyere at the tymp : with two tuyferes, it is 
 still advisable, because the two nozzles should never be opposite exactly, and room for their play is 
 desirable, as well as a better distribution of the blast. So far as the resistance to the blast is con- 
 cerned, it will be in equilibrium by an addition of § of the width to make up the length. 
 
 The jambs of the hearth are made vertical, or with various degrees of batter, from -h-, at a minimum, 
 to ^ , at a maximum, of the height ; and generally inversely as the height. This last proportion seems 
 unreasonably great, and must embarrass the blast. But the absolute capacity of the hearth must be 
 taken in as an element for determining the batter; as also the quality of yield which is aimed at. To 
 make foundry-iron, the batter should be less than for forge-pig. The proportions of W. of the height 
 for the former, and A for the latter, seem to be warranted by the best examples. 
 
 The slope of the boshes, or angle which a section of their face makes with the horizon, varies from 
 55° to '70°. There are some instances in the Harz of less inclination than this; but it is not recom- 
 mendable. A slope of 60° might be taken as a constant to present the maximum advantage ; for, 
 strictly speaking, the pressure of the blast can be regulated so as to compensate for unsuitability ol 
 slope, iu any particular case, to the materials. In respect to these last, refractory ores and soft char- 
 coal are best treated with a less slope ; but fusible ores, and coke, or charcoal of hard wood, will behave 
 better with steep boshes. The length of the boshes, which are now always circular, corresponds with 
 the greatest diameter of the furnace, or, as it is technically called, the width . at the boshes. 
 
 This width, it is obvious, must be proportionate to the height of the cuvette, or, it may be said, the 
 whole height of the stack ; i. e., the higher the furnace, the wider it may be with the same materials. 
 But with a given height, the width should vary according to the materials, and vice versa. These two 
 items, therefore, will have to be considered together in this respect ; and, along with them, another of 
 the greatest importance — the quantity and pressure of the blast furnished. And, after all, we can only 
 deal in generalities, and not in arithmetical proportions, which can only be derived, for a given case, 
 with materials of known composition and properties. The object of the furnace, at all, is to generate 
 heat to melt some of the materials, and to melt them, also, at a proper place. This heat is produced 
 bv the combustion of others, (viz. the fuel;) and the amount of such heat depends upon the quantity 
 of these last burnt in a given time ; which quantity, again, depends upon the weight and volume of air 
 furnished in the same time — i. e., upon the amount of blast. The greater the blast, the more fuel will 
 be burnt, the more heat generated, and the more matter melted in a given time. Assuming, then, the 
 blast as constant and suitable, the stack should be of such a height as that none of it will pass out 
 unaltered at the trundle-head. It is manifest that, with a low furnace, a part of the air of a strong 
 blast will come out at the top without having promoted combustion at all, and, therefore, at a loss 
 With the blast constant and the height suitable to that, the next thing is to consider the effect of the 
 width at the boshes. At this point the materials have attained their greatest extension, and are ready, 
 some for being burnt, some for being melted. If this space is too narrow the ores will arrive too soon 
 at a high temperature ; fusible ones will liquefy in the upper part of the furnace, refractory ones will 
 fall in fragments into the crucible, not having had opportunity to be properly cemented and reduced. 
 It, on the other hand, the width be too great, the temperature will be insufficient, and even fusible 
 mines will descend unaltered into the crucible. This will be especially the case with charcoal furnaces, 
 whose' fuel, more friable, does not afford the same resistance. So far as fuel is concerned, then, boshes 
 for charcoal other things being equal, must always be less wide than for coke ; and even for another 
 
88 
 
 iro:n. 
 
 reason, that the light charcoal is easier blown aside by a strong blast, in which case it is burned against 
 the sides of the stack, where its combustion is comparatively useless. It may be concluded, then, that 
 the width of boshes, with a given height of stack and given blast, should be less for a friable fuel and 
 for refractory ores than for a compact fuel and fusible ores. 
 
 Upon the boshes rest the in-walls , and their junction should be effected to present the least angle 
 possible. The materials of these, as w r ell as of the non-conducting and elastic lining between them and 
 the solid masonry of the stack, have been already spoken of. Their horizontal section is always circular, 
 the vertical projection of their face sometimes a straight, sometimes a curved line. The former is more 
 easy to build, the latter more retentive of heat, and, with a mould-board revolving round a central shaft, 
 presents no difficulty in construction. In forming the curve of this mould-board, the shape of a common 
 parabola is the most advantageous to be employed in respect to the distribution of heat. 
 
 The width at the trundle-head depends upon the quantity of blast intended to be furnished, and also, 
 in a less degree, upon the quality of the materials. If the blast is very strong, it should be less than 
 with a weak blast ; it should be large with friable fuel, and ores that tend to stick together. The 
 widening below should not be rapid, as if, for instance, the parabola before spoken of were cut off near 
 its vertex, for the materials in that case would tend to distribute themselves unequally ; relieved sud- 
 denly from lateral pressure, the heavier ores would descend quicker than the charcoal or cokes. The 
 general practice is to make trundle-heads narrower than theory wruld dictate, under an apprehension 
 of loss of heat ; their width should not be less than 2-5ths, and in most cases might be advantageously 
 i that of the boshes. 
 
 The chimney surmounting the trundle-head is not always adopted ; in proportion to the size and 
 temperature of the furnace it is more and more necessary. It is built uniformly of brick upon a cast- 
 iron bed-plate, with mortar only enough to hold it together, and further retained in shape by ribs and 
 hoops of iron. Its height is from one-fifth to one-fourth that of the stack, and its inside top-diameter is 
 generally wider by the length of a brick than its base, the outside face of the wall being plumb. 
 
 The only remaining part of the construction which has not been mentioned is the stack, whose func- 
 tion, it is apparent, is only that of a retaining-wall to hold the cuvette, boshes, &c., in place. This 
 function it may perform either by its inertia or by its cohesion. In the first alternative it is generally 
 built of stone-masonry, laid dry where it approaches the lining, and mortared elsewhere; externally it 
 will be square, the width of the base will be equal, or very nearly so, to the height of the whole stack 
 above the foundations, and the outside face will be battered at from 2£ to 3 inches per foot, thus making 
 the width at top about half the width of the base. These are, of course, only average and generally 
 unobjectionable proportions. Besides this, in levels of every 4 or 5 feet, binders of bar-iron are laid in 
 channels of 12 or 16 square inches of section left in the masonry parallel to all four sides, which binders 
 are held at the ends by suitable holdfasts that can be tightened either with a key or with a nut. 
 When these bars break, (as they not unfrequently do,) they can be drawn out of their channels and 
 others substituted. Besides these horizontal channels, there are vertical flues left in various parts ol 
 the stack to promote the expulsion of moisture, which otherwise would volatilize into steam, and accel- 
 erate the cracking of the masonry. This tendency to crack in the stack seems so confirmed that there 
 is hardly a furnace of any considerable size in the world which does not show it. Except for a certain 
 loss of heat these cracks do not injure a furnace, provided the in-walls remain unhurt. Finally, there 
 is a dust-flue (in large furnaces) communicating from the top with the tymp-arcli. 
 
 2350. 2351. 
 
 When, as in the second alternative, it is the cohesion of the stack that is relied on to retain the in 
 .•alls, it is generally built of bricks, circular, and tied with many vertical staves and hoops of wrought- 
 iron. Such stacks are generally termed cupola blast-furnaces, but they are never of the largest 
 
IRON. 
 
 8'j 
 
 dimensions. The external proportions vary according to the fancy of each builder. Fig. 2350 shows 
 an ordinary furnace of this sort; Fig. 2351 another, remarkable for appropriateness, ingenuity, and 
 taste. 
 
 Blast-furnaces have universally a roof, over the ground adjacent to the front and sides, of greater or 
 less extent, called the moulding-house ; and one, adjacent at the top and approaching more or less near 
 to the chimney, called the top-house, or bridge-house. The necessity of these in protecting from weather 
 the workmen, materials, and metal, is obvious. They are also advantageous in proportion to their ex- 
 tent, the spouts with which they are furnished, <fec., in keeping the foundation, (fee., of the furnace itself 
 dry. As far as possible, the materials used in these buildings should be iron, to avoid risk of fire. 
 
 The difference of materials in furnaces has been frequently spoken of already as entailing a difference 
 in dimensions. The principal influence in this respect is due to the fuel ; and hence there is a marked 
 difference in size between charcoal and coke furnaces. The necessity for this is apparent, when we 
 consider, that with equal volumes, the heating effect of charcoal is but one-half that of coke ; of two 
 furnaces, then, of the same size, the one fed with charcoal can never be raised to so high a temperature 
 as the other, for even the most obvious steps towards equalizing them (viz. continually supplying fresh 
 charges of charcoal) have of themselves a cooling tendency. 
 
 The following table will show, at a glance, the comparative dimensions, <fec., of these two classes of 
 furnaces, established upon what is considered a fair average of each. The particulars under the head 
 of anthracite are taken from what may be regarded as the latest improvements for the uje of that fuel 
 
 Dimensions. 
 
 Hig 
 
 Charcoal. 
 
 'h-fu maces, using 
 Coke. 
 
 Anthracite. 
 
 Stack, height from foundation 
 
 35 feet, 
 
 50 feet, 
 
 35 feet. 
 
 width at base 
 
 28 “ 
 
 50 “ 
 
 40 
 
 width at top 
 
 167- “ 
 
 25 “ 
 
 33 “ 
 
 Cuvette, diameter of trundle-head 
 
 4 
 
 8 “ 
 
 0 “ 
 
 height of conical in-walls 
 
 257- “ 
 
 33 “ 
 
 it 
 
 do. cylindrical 
 
 — 
 
 — 
 
 8 “ 
 
 width at boshes 
 
 9i “ 
 
 15 “ 
 
 12 
 
 angle of boshes 
 
 55 degrees, 
 
 65 degrees, 
 
 75 degrees. 
 
 height of boshes 
 
 4J feet, 
 
 10 J feet, 
 
 1 1 feet. 
 
 Crucible, height of hearth 
 
 5 “ 
 
 6* “ 
 
 5 
 
 mean of length and breadth at top 
 
 24 “ 
 
 5 “ 
 
 6 “ 
 
 do. do. at bottom 
 
 2 tl 
 
 4 “ 
 
 4 
 
 height of tuybre above hearth-stone 
 
 Approximate capacity 
 
 Descent of charges in about 
 
 U “ 
 
 1000 cub. feet, 
 20 hours, 
 
 2 “ 
 
 4500 cub. feet. 
 40 hours. 
 
 If “ 
 
 These dimensions and proportions undergo changes, necessarily to be accommodated to different ores, 
 they are often arbitrarily modified besides, or follow a routine established at earlier periods of the art 
 of smelting. Thus, in South Germany, the old Jluss-ofen is still substantially retained ; in Sweden, 
 many high-furnaces are still erected without a crucible, i. e. with a continued talus from the top of the 
 boshes to the hearth-stone ; in Wales, where the product surpasses that of any other part of the world, 
 the furnaces are lofty and vast — some (but an unsuccessful model, it is said) attaining a height of 70 
 and a width of 20 feet ; the English furnaces of Staffordshire are lower, but, in proportion, more wide ; 
 the Scottish are more cylinder-like and squatter, still. In America, there cannot be said to be any pre- 
 vailing type for charcoal works ; the coke furnaces are said by Overman to be generally on the model 
 of the first successful one, — that at Lonaconing in Maryland : while the use of anthracite as a fuel has 
 yet received so little extension as hardly to present more than a few instances. 
 
 With these explanations of the means made use of) we can now pass to the materials employed in 
 the smelting of iron, and their respective preparation. 
 
 1. Fuel. This is one of the most important materials, both in regard to quality andcost. We have 
 already seen that it constitutes the index in a classification of furnaces ; and when it is considered that 
 there are many situations whose ores cannot be availed of because of the inconvenient supply of fuel, 
 the propriety of placing it first in the list of materials will be apparent. The object in the use of fuel 
 is principally to obtain heat, but it also acts in the furnace upon the other materials as a reducing and 
 deoxidizing agent. In both of these aspects, its value is in proportion to the carbon which it contains ; 
 and in the last aspect, it is not mere flame or heat which is wanted in the furnace, but the contact also 
 of carbonaceous matter with the materials to be reduced. Wood, whose chemical constitution may be 
 taken in general at 50 per cent, of carbon and 50 per cent, of oxygen and hydrogen, in proportions form- 
 ing water, contains too little carbon in its natural state to be advantageously employed in a furnace. 
 Compared with coke, its calorific effect under equal volumes is but one-fifth of the latter ; it therefore 
 would not raise the temperature sufficiently. It has been attempted to be applied in a baked or torri- 
 fied state, but not with sufficient success to induce a further use. The presence of hydrogen, which pro- 
 motes inflammability, and which, although under some circumstances it acts as a deoxidizer, does not 
 so act in a furnace further than upon the combustible itself, is a permanent obstacle to the employment 
 of all fuel in proportion as it exists. Hence raw coal is, in general, improper; turf and lignite, or brown 
 coal, are in the same category. The last named burn too much in the attempt to carbonize them ; but 
 pressed and chaired turf is quite extensively used in France, Germany, and Russia, for the manufacture 
 of iron. For smiths’ work, it is said to furnish a charcoal of peculiar excellence. In America, where 
 there is so much other fuel of a character as unquestionable and of supply more convenient, its consid- 
 eration may as yet be left out of question ; and all that will be treated of here is the preparation of 
 wood and coal, the one by charring, the other by coking, for the purposes of the iron-master. The gen- 
 
90 
 
 mo jn . 
 
 eral principles of carbonizing either fuel are the same : viz., the expulsion, by heat, without contact ol 
 ah', of the volatile constituents of the fuel. These constituents go off in part as gases, containing more 
 or less carbon, and, in part, as new combinations which are still liquid at a high temperature ; as, for 
 instance, acetic acid, tar, &c. The distillation of wood or coal, with a view to economizing any other 
 products than residual carbon, does not form any part of the business of iron-working. 
 
 The means, too, for carbonizing either fuel for this special metallurgic use are similar, in kind, though 
 the details of the methods vary for both considerably. These details may, however, be grouped into 
 two great classes: 1. Where the carbonization is effected in a permanent, air-excluding oven: 2. Where 
 it is done in clamps, or kilns, or heaps. In the general aspect of carbonization, the means employed 
 would have to be antecedently classed according as use may be made, first, of other fuel than that to 
 be carbonized, in order to general e the requisite heat, or secondly, of a part of the mass itself, for the 
 charring of the other part. The type of the first system is seen generally in all the apparatus where 
 other products than carbon are sought to be collected, and where the coke or charcoal are incidental to 
 the operation ; as in gas retorts, or the cylinders for pyroligneous acid or wood vinegar. Although a 
 system like these might, in some localities, where fuel was abundant or in different qualities, be ad- 
 vantageously introduced, there is probably no iron establishment where it is resorted to ; and the other 
 classification, of ovens or kilns, remains as the only one that need be discussed here. 
 
 The relative advantages of these two methods can only be ascertained by a comparison of their prod- 
 ucts in quantity and quality. With respect to the first element, quantity, it may be assumed (though 
 it is not universally admitted) that ovens produce a greater quantity, by weight, of carbon from the 
 raw material. Hardly any collier can claim a yield of more than 20 per cent, of charcoal, for instance 
 from heaps ; while the best ovens, with perhaps less trouble, though not less expense in individual 
 cases, will give about 25 per cent. Again, in the assemblage of cases, the expense for ovens is proba- 
 bly less ; being less exposed to accidents from weather, neglect, &c., which sometimes result in the 
 combustion of an entire kiln. 
 
 With respect to quality of product, the evidence is less decisive. It would seem in theory that the 
 oven, producing a greater weight of carbon, ought also to produce a heavier material, per se. But such 
 is not always, nor even generally, the case ; and where the oven charcoal or coke are of the highest 
 specific gravity, (and the economy of a high specific gravity is, in general, undoubted,) yet from some 
 cause, such as a peculiar arrangement or disarrangement of fibres, it is not found to develop so much 
 heat as that prepared in kilns. This point of quality, therefore, and, indeed, the whole question as 
 between ovens ^and kilns, need a more profound and extensive investigation. All that will be done 
 here is to describe the most usual and simple details of both methods-, first, for charcoal, and then, 
 for coke. 
 
 Charring of wood is still practised in Austria after methods which seem to have originated under the 
 period of Roman domination, for the manufac- 
 ture of the celebrated Norman iron. These may 
 be denominated charring in heaps, (Germ, hauf- 
 en,) or clamps ; and will be understood from 
 the accompanying sketches, of which Fig. 2352 
 shows a side-view, and Fig. 2353 a ground-plan 
 of the arrangement. The ground for this may 
 be either levelled or sloped. In either case, 
 pipes ate sometimes, but rarely, laid in the up- 
 per parts of the clamp, to carry off some of the 
 liquid products. The length of the clamp (and, 
 of course, the number of posts) is arbitrary — gen- 
 erally from 40 to 50 feet ; the width depends 
 upon the length of the logs, which, being ordi- 
 narily 4 feet, and being laid in a double row, 
 with a very small space, to the casing of the 
 sides, will make the width very nearly 9 feet 
 across, from post to post. In Fig. 2353 the logs 
 are given as if in but one length, which can very 
 well be if the sticks are light. The casing may 
 be of plank, slabs, or split cord-wood. The ground is well pounded ; and, if in an old burning, with 
 charcoal and dust. The logs are then piled, beginning from the upper part, to within a few inches o) 
 the top of the casing. Then it is covered with chips, twigs and leaves, and finally with sand or (better) 
 dust, which material is also filled in against the casing, to protect it from fire. After all this is ready, 
 fire is put in at the lower end, and some of the dust is removed from the upper end to make a draught. 
 Draught-holes are also opened at discretion in the sides of the casing. When the smoke comes out 
 where the dust is removed, it is necessary to throw it on again, and open elsewhere with caution. In 
 this manner the fire is. led on till the heat has charred the whole. The peculiar advantage of this 
 method is supposed to be, that with a clamp, say of 50 feet, charcoal may be drawn from the lower 
 end after the fire has progressed about ten feet, which it will do, ordinarily, in twenty-four hours. This 
 is still further helped by making it on sloping ground. If well packed, a clamp of 50 feet by 9 feet, 8 
 feet high at the head, and 3 feet at the foot, will hold about 15 cords. 
 
 Another method, more extensively and commonly practised, is that of kilns, (Germ, metier ; Fr. 
 meules.) These kilns are of two kinds, standing and lying ; the wood standing on its end in the one, 
 and lying on its side in the other, as shown in Figs. 2354 and 2355. 
 
 The circle, to be levelled and pounded down, for a kiln of this sort, will be from 40 to 50 feet in 
 diameter; the driest ground must be selected for the purpose, and a place sheltered from winds. The 
 best period for burning, in America, is from the middle of May until the middle of August ; and then 
 
 235-2. 
 
IRON. 
 
 91 
 
 again in October and November, during the season known as the Indian summer. Wood which has 
 been felled, and lopped, and barked in December and January, will be sufficiently seasoned to char in 
 the autumn following. After the logs have been arranged, as in the figures, around the three long 
 stakes of ten or twelve feet in length, (which are to serve as a chimney,) and piled as evenly and com- 
 pactly as possible, the whole pile must be covered to keep out the air. A site for a coaling improve 1 ' 
 2355. 2354. 
 
 by use, for the charcoal and loam get trodden and mixed together, forming the best material for the cov- 
 ering. On entirely new ground use must be had of sod. When covered, fire is applied, either through 
 the top and suffered to fall through to the centre, where provision has been made of some light wood 
 to catch readily, or through a horizontal flue left along the ground, which is closed at its entrance as 
 soon as the fire has taken. For the first twelve hours the kiln must be closely watched, and, therefore, 
 it is usual to light at daybreak. At the end of that period, or a little longer, according to the kind of 
 wood, its state of seasoning, and the skill of the collier, the fire will have taken sufficiently, and the top 
 may be covered in with dust and loam. From that time, it is better that the operation should proceed 
 as gradually and slowly as possible. In three or four days the cover begins to shrink and fall in, and 
 fresh watchfulness is required to stop every opening thus made, and even new ones are made to effect 
 an equable distribution of heat. These are points that cannot be taught by talking ; they are lessons of 
 experience and observation. When the cover sinks gradually, and the smoke grows less and less, reg- 
 ularly, the work is known to be going on well. Expert colliers find indications of the process in the 
 color of the vapor and smoke, which varies at different stages. After all smoke has ceased, the kiln is 
 entirely and thickly covered, and left for four or five days, less or more according to its size, to cool. 
 The coal is begun to be drawn from the foot, but cautiously at first, until it is found to be too cool to 
 re-ignite upon admission of air. If so, the drawing may be continued all round for coal that is wanted, 
 peeling it off, as it were, like an onion ; the whole contents may be hauled off to store, or it may be left 
 (covered up again) to be resorted to when wanted. In proportion as the kiln is well piled, flues in 
 various places are unnecessary. It sometimes happens that the fire takes in particular parts, or does 
 not take at all. In this last event, the advantage of a horizontal firing flue is tested. A kiln of ordi 
 nary size, of this kind, holds about 30 cords ; the largest contain 50 cords. 
 
 When the circumstances are such as to render it likely that' the same charring-ground will be used 
 for a considerable period, it is worth 
 while to adapt to it some permanent 
 accessions, as indicated in Fig. 2356 ; 
 which represents the section of a 
 basin laid in dry brick, to serve as 
 the ground of the kiln. This basin 
 has a pit at p, with a cast-iron cover 
 c, to keep ashes out, and a gutter, </, 
 communicating with the tank t, which 
 
 receives the liquid products of carbonization. With resinous wood, these products are advantageously 
 removed as soon as possible from the charcoal, and are valuable when caught. The tank has a lid, i, 
 which must be laid over it and luted when the kiln is fired. 
 
 Midway between ovens and kilns comes the shroud or abri of Foncauld ; of which a side-view is 
 shown in Fig. 2351, and an orthographic one in Fig. 2358. It consists, in fact, of a series of trapezial 
 ladders, made of light frames, and capable of enclosing a circle at the base of 30 feet, at the top of 10 
 
 (eet, with an elevation of 8 or 9 feet. The sides of these frames are furnished with mortises or lugs, 
 by which two adjoining strings can be keyed together with wooden bolts. The top is a flat cover of 
 
92 
 
 IRON. 
 
 scantling, with traps that can be opened or shut for the passage of air, and also for that of a conduit 
 made of three pieces of light plank, for the condensation of gaseous products. The effect of these lad- 
 ders is to allow of a better packing (and, as it were, thatching) of the ordinary loam covering of kilns. 
 Fire is applied, and air furnished at first through the door d, left in one of the ladders. The charcoal 
 furnished by this method is said to be of superior quality ; its yield is stated at 24 per cent, of the 
 wood, with 20 per cent, besides in crude pyroligneous acid. This yield of charcoal is about one-fifth 
 more than from the kilns that have been described. 
 
 Of ovens there is a great variety of form ; but as tire most of them are embarrassed with apparatus 
 for collecting other products besides charcoal, they are more connected with distillation than carbon- 
 ization for the manufacture of iron. Only one, of the most simple and economical form, and yet yielding 
 good results, will be described. A portion of it is shown in Fig. 2359, which is supposed to give a tol- 
 erably clear idea of the plan. The building from which this is taken is about 50 feet long, 12 feet wide 
 in the clear, and 12 feet high, and will hold, well packed, about 60 cords, a quantity that has been found 
 to present the maximum of convenience and economy, c shows the chimney-hole in the centre for firing, 
 ff flue-holes foi the draught, of which there are others on top which cannot be seen. At the ends 
 there is a small door for charging and drawing. The stays are of cast-iron or wood, the horizontal 
 binders on top of bar-iron. Wooden scantling was first used for both these, but it is neither so safe nor 
 so strong. The arch which is sprung for the top is low, but yet, when the fire is in, there is considerable 
 thrust against the walls. These walls are 1-J brick, and must be well laid and joined. As the acetous 
 products in the oven are apt to attack the lime, asphalt, or a bituminous cement made of coal-tar and 
 loam, is used instead of ordinary mortar. Coal-tar is also advantageously used for coating the outside. 
 The wood is piled lying, as is seen in the figure. Under the chimney-hole, a chimney (so to call it) is 
 left in the pile, at the bottom of which the fire is placed. The wood may be kindled through the 
 draught-holes or at the doors, but less economically. When the fire is first started all air-holes are shut; 
 when it is fairly caught the chimney may be filled up with dry wood, the hole closed, but not tightly, 
 and air-holes opened at the ends. This will happen in seven or eight hours. The operation must now 
 be watched, and by the emission of smoke and vapor through the air-holes, a judgment may be formed 
 as to where they should be shut and where opened. In 45 to 50 hours the whole oven will have been 
 heated ; all openings are then closed and luted, and the concern left for three or four days to cool. On 
 the fourth or fifth day at latest the coal should be fit to be drawn. 
 
 To what has been said, may be added some generalities as to the choice of wood and quality of the 
 charcoal. The denser woods are to be preferred, because, other things equal, they afford a denser and 
 harder charcoal. Decayed or doted wood will not yield a good article ; and charcoal from green wood 
 is more light, more friable, and less calorific than from dry, besides being less economical in the manu- 
 facture. The trees should be felled when the sap is down, i. e. in the winter, from December to 
 February. Small timber is in general, and young timber always, worse than that which has attained 
 a larger and more mature growth. Yet very old wood is not so good, because there is always more or 
 loss decomposition of the fibre. Branches of trees give less and a lighter charcoal than the boles, and 
 the best of all is furnished by that part of the trunk and roots nearest the ground. In the ordinary 
 felling of trees this part is all lost. Hence it would be better for the purpose (and the land would be 
 left in a better state) to extract the trees at once by the roots, as is very easy, and then saw the timber 
 instead of cutting. Heavy charcoal produces more heat, but its reducing effect is not in every case in 
 proportion. There are some mines with which lighter charcoal acts better ; but that it should be hard 
 is an important characteristic universally. Charcoal just from the kiln burns quicker and produces 
 less heat than that which has been kept some time in store, yet very old charcoal is admitted to be less 
 valuable than what has not passed over one season. To what this is owing is not clear, for the affinity 
 of the material for moisture is exercised very promptly, and after the first 24 hours, in an ordinary 
 atmosphere and with reasonable precautions, it does not materially increase in weight. It is better to 
 keep charcoal in store than to leave it stored in the kiln. After it has grown cool enough to handle, 
 the sooner it is made quite cold the better; all gradual expulsion of heat, such as occurs in a kiln, is at 
 an expense of carbon. With ovens this caution is unnecessary, for the circumstances there always 
 compel removal of the charcoal as soon as manufactured. The product in charcoal ranges from 18 to 
 22 per cent, in kilns, and from 20 to 25 per cent, iu ovens. By volume a cord of wood, 128 cubic feet, 
 well corded, ought to give, at a mean, 40 bushels of charcoal. The price depends, of course, upon the 
 value of labor in every locality, and the distance of hauling. The chopping of a cord of wood is equiv- 
 alent to about one-tliird of a day's labor in the abstract, and the coaling of it in kilns or clamps after- 
 wards to about a half day. The computations of the charcoal-burner are usually made upon the 100 
 bushels of charcoal delivered. Coaling in ovens, although in fact less laborious and demanding less 
 experience, requires more tact, and wages there are generally higher. 
 
 The charring of coal, or coking, (from the German word kochen, to cook,) is the same in principle as 
 that of wood, and the processes are very similar, though in some respects the considerations are different. 
 Thus the coker does not fear, like the charcoal-burner, either air or moisture, nor is he troubled with the 
 shrinkage and falling in of the kiln. On the contrary, for coke there has to be a large supply of air to 
 determine combustion at all ; the volume is in general increased during the process, while moisture, 
 during the earlier stages, (but after the fire has obtained full way,) is recommended as a desulphuret- 
 ting agent. It does, in fact, so act, but hardly to the extent that is claimed for it in theory, and some 
 times supposed in practice; for the proportions of sulphur remaining in the coke from the same coal, 
 treated either way, do not appreciably differ. On the other hand, coke-burning, subject to the same 
 general category of regularity and manageability of temperature, and therefore when in the pure air 
 liable to accidents from high winds, <fee., of the same sort as occur to charcoal kilns, has to undergo 
 constantly a greater per centage of loss from combustion. This loss is, on the average, about 6 per 
 ’eut., so that coal which, on analysis, shows 85 per cent, of carbon and earthy matter, will rarely give 
 80 per cent, of coke, allowance being made for the quantity (from 5 to 10 per cent.) converted into rtack. 
 
IRON. 
 
 93 
 
 Coke is made in heaps , in clamps, and in ovens. A suitable contrivance, and much used for heap-coking, 
 is shown in Fig. 2360, the central shaft of which is a cylindrical or conical chimney loosely built of 
 brick, (terminated in the sketch as in Staffordshire, 
 with a cast-iron chimney-liead,) against which the 
 coal is piled conically, not tightly, and often with 
 regular flues and intervals left between the masses. 
 
 As with wood, the heaviest lumps are near the 
 centre, the lighter outside. Coke-dust and slack- 
 coal are used as a cover and for stopping. Ig- 
 nited coal or coke is thrown in the chimney, and fire 
 is sometimes introduced by the horizontal flues be- 
 low. After the fire is started, similar precautions are required as with charcoal. The height of the 
 chimney is from 5 to 6 feet, the diameter of the heap from 14 to 16 feet, and it will take from 10 to 12 
 tons of coal. As the process advances, slack-coal is thrown on in some places, and openings with a 
 crow-bar made in others, according as the coker wishes to direct the heat, and water is injected plenti- 
 fully, both to control the heat and desulphurate the fuel, if it is supposed to need it, and finally to put 
 out the fire. A heap of the size given will be thoroughly coked in two and a half or three days ; it is 
 then left four days to cool, the whole operation requiring about a week. 
 
 In Wales clamps are more used for coking, which are long piles 6 or 6 feet wide, 2J to 3 feet high, 
 and in lengths varying according to the extent of coke-yard, from 60 to 100 feet or more. One of 60 
 feet will be of 30 to 40 tons. The coal is piled as in the other method, the largest pieces inside, loose 
 throughout, and with horizontal flues. In place of the chimney, however, a stout stake is driven in the 
 middle of the width and at every two yards of the length, to serve as a guide in piling. When the coal 
 is piled the stakes are pulled out, and the space they leave becomes a chimney, into which the fire is 
 placed as before. Sometimes the clamp is fired in its whole length at once ; most usually it is fired at 
 but one end, (regard being had to the state of the wind at the time and its probable permanence,) and 
 even before the piling at the other is finished, so that it is a common thing to see coke drawn from one 
 end and coal piled on the other end of a clamp at the same moment. The coke yielded by either of 
 these methods is supposed to be better for iron-making than by any other way ; but they are both 
 costly in coal consumed, the latter especially. Where, however, as in the districts of its principal 
 employment, coal is abundant and cheap, it presents divers conveniences which are probably cheaply 
 purchased. 
 
 Slack-coal, i. e. coal beaten and comminuted in very small fragments or powder, (Germ, schlag, a 
 stamp, a blow, and, by metonymy, a crushing, and the thing crushed,) of suitable quality, is also capable 
 of being converted into good coke by a somewhat similar process. If the slack be from very dry coals, 
 i. e. which do not contain much bitumen, it will not, however, coke at all ; if the coal be too fat, i. e. 
 with too much hydrogen, it will run together on the application of heat, embarrass the circulation of air, 
 and yield a small proportion of a very friable and inferior article, if it does not defeat the whole opera- 
 tion. Assuming the coals to be of suitable quality, it may be treated by being mixed in small quan- 
 tities, well wetted, in a kiln or clamp with larger coal. But the best method is to screen it first, and 
 thus separate all the egg and nut-sized lumps from the mere slack, or pure powder. This last is mixed 
 with water abundantly, and can be beaten from within against a wooden mould or shroud. Provision 
 must be made by laying smooth and somewhat conical tampers of wood horizontally and vertically 
 through the mass, for air-flues. These tampers are afterwards drawn out, and some larger than the 
 rest, towards the top, leave the means of introducing already ignited coal to fire the mass. It is better 
 to fire at the top than below. 
 
 . Fig. 2361 will give an idea of the ar- 
 rangements proper for this method, which, 
 preserving the main principle, are of course 
 susceptible of many variations in detail. 
 
 Thus they are sometimes made circular, 
 but the most usual form is, as in the figure, 
 an elongated prism, 50 to 60 feet in length, 
 from 4 to 8 feet wide at the base, and from 
 2^ to 6 feet at the top, and 3 or 4 feet high. 
 
 A greater width, up to 15 feet, has been 
 tried, but not to advantage. Of course a 
 mould and cores of the whole length are 
 not necessary, but after a portion has been 
 finished the shrouds and tampers can be discreetly moved further on and the clamp extended. Iron 
 rings are indicated at the end of the tampers, through which a lever is passed to assist in their removal. 
 The quantity and quality of coke made, due care being taken in the process, is in proportion to the 
 quality of the coal, and about 80 per cent, of the quantity yielded from the same slack in ovens. A 
 clamp of the size mentioned will take about ten days to coke and cool. It is better, on divers accounts, 
 to leave it to cool, rather than extinguish it by cold affusions. 
 
 Fig. 2362 is an elevation and plan of two ovens of a series, especially applied to the coking of slack, 
 but also capable of being used as well for lump-coal. It is supposed that the sketch makes it quite 
 intelligible, without further description. Tire doors at each end render the emptying of the oven very- 
 convenient. The average dimensions are about 16 feet long, 8 feet wide, and 4 feet high to the arch 
 The diameter of the chimney (which is generally a cylinder of a single brick, or refractory pottery) is 
 ordinarily 16 inches. The hearth and arches are best made of fire-brick. The foundation of the heartk 
 may be of stone or common brick, with a filling of a foot at least of sand or furnace-cinder interposed 
 between it and the floor of the hearth proper Such an oven will hold from 10 to 12 tons, and the 
 
 2300. 
 
 
 rnmmm&m 
 
94 
 
 IRON. 
 
 coking, including cooling, is done in from 40 to 50 hours. It is not well to let it cool too long, or to such 
 a degree that the slack will not be speedily ignited on contact with the hearth. In this respect, the 
 oven, like a common bake-oven, works better for longer use. The first yield of coke from the cold oven 
 is inferior to what is made afterwards. There can be no doubt of the greater economy of ovens fo* 
 slack-coal. 
 
 Another sort of oven suitable for slack-coal resembles very much the bank-ovens for lump-coal that 
 will be spoken of presently. The ground-plan is circular, the roof slightly arched, the only mortar used 
 fire-clay. Flues are carried all round, communicating at generally three points with the interior. There 
 is but one door tor drawing, and the filling is done through the top ; for greater convenience in whicli, 
 they are generally built against a bank or sloping ground. 
 
 2363. 
 
 Fig. 2363 shows an oven of a different construction, much used in Silesia, both for coking and also for 
 coal-tar. For the former purpose alone the ash-pit and damper d may be dispensed with, sufficient 
 draught being furnished through the flues//, &c. The opening in the section shows the door through 
 which the fire is introduced, and which is afterwards bricked up. The filling is done from above through 
 the throat, whose cover c is, after firing, luted down. The flue for the escape of the tar is shown at t. 
 
 The oven in most general use, both on the Continent of Europe, in England, and in America, has a 
 circular or ovoid ground-plan, with a low, arched roof, to allow for the swelling of the coal. The draught 
 is regulated by a damper in the door, and sometimes by flues communicating with the interior ; the 
 filling is in part effected by the door, and in part through the chimney, the fire applied generally through 
 the last. The backing of the arch is filled up square, and, to save masonry, the building is generally 
 made against rising ground, whence they have the name of bank-ovens. 
 
 Fig. 2364 shows a section of one of these ovens, for holding about two tons of coal. In England they 
 have generally more or less of a chimney, 
 and not unfrequently two more smaller 
 apertures in the same axial plane to assist 
 the draught. Also, there, the doors are 
 usually of iron, sliding vertically in a frame 
 and balanced; in America, the doorway 
 is generally bricked up, and as this is al- 
 ways but temporary masonry, in such case 
 iron staples are let in on each side for re- 
 ceiving a bar that may resist the thrust 
 from within of the expanding coal against 
 the brick-work. For economy of building 
 and heat, several ovens are generally ranged in one stack. 
 
 One of the most simple and at the same time serviceable forms of oven is that employed at. Newcastle 
 and its neighborhood, which serves equally for lump or for slack coal. It wa9 devised, indeed, princi- 
 pally in the view of economizing the last. The ground-plan of these ovens is rectangular, 13 feet by 
 10 or 11 feet, covered with a low elliptical arch, (a parabolic one would be better,) whose crown is 
 about five feet above the hearth, clear inside measurement. They have but one door, sliding in a close 
 foint, as before mentioned, about 2 feet high and l-J wide, with a register-door in its centre of 3 inches 
 square for admitting or shutting off the air. The draught is further managed by three chimneys in the 
 arch, the main one, of about 1 foot square, in the middle, the others, about 4 inches square, at equal 
 distances from the central one. This last has, as usual, a cast-iron cover; the others are closed with a 
 brick. The coke from these ovens is supposed to be verv good. 
 
 In regard to the advantages of the two methods of coking, in the open air or in ovens, it may be said 
 that there is less loss and less labor of attendance with ovens, but more skill is required in managing 
 
 2364. 
 
IRON. 
 
 95 
 
 the temperature. Thus, for instance, if the heat is got up too quick, (as it is very apt to be,) the coko 
 with fat coals is spoiled by burning out too swoln, light, and friable ; with dry coals, it burns up and 
 causes loss. Also, ovens yield, on an average, about 10 per cent, more coke, but generally of less spe- 
 cific gravity and more friable. Whether less care is taken in the selection of the coal for ovens, as is 
 probable, it is certain that the almost universal experience of iron-masters is in favor of coke made in 
 the open air on the score of useful effect. Again, the yield from ovens is more uniform, and less subject 
 to accidental discounts. Besides, ovens allow more readily the use of slack or refuse coal, to produce 
 an article of the same value. The oven- coke, then, charged, too, with the greater labor required in 
 drawing and the higher average wages of the cokers, is the cheaper in actual outlay ; but its final 
 cheapness, in which the quality of the product is an element, because of the varying degrees of its infe- 
 riority, which depend too much upon the constitution of the coal used in different places, hardly allow- 
 ing a satisfactory comparison. Coke made in retorts is undoubtedly the cheapest of all, but its quality 
 unfits it for use in the smelting of iron. 
 
 So great an effect has the physical constitution of the coal upon the coke produced, that experience 
 shows the quantity of coke ranges in different places from 45 to 90 per cent, of the original weight of 
 coal employed. About fths of coke would be, most likely, a fair average of all known results on the 
 large scale. Experiments made in small, or calculations upon the chemical analysis of coals, are no 
 further admissible or of use, in this respect, than to stimulate the manufacturer to an investigation and 
 economization of his actual results. 
 
 Regard being had to volume yielded, most coals expand in coking ; some are unaltered, and some, 
 even where a large proportion of earthy matter is principally aluminous, shrink. The resulting volume 
 with the swelling coals is nearly, but not quite, nor always, -in proportion to the loss of weight. Thus, 
 Johnson, in his report to the Navy Department of the United States, in 1843, states, for a specimen 
 of coal from Allegany County, Maryland— 
 
 Loss in weight, per cent.; gain in bulk, per cent. 
 
 The physical properties of this coal are stated by the same observer as under : — 
 
 Weight of a cubic foot. Per centage of 
 
 Sp. gi-av. Calculation. Experiment. Volatile matter. Carbon. Earthy matter. 
 
 1-337 83-3 lbs. 54'3 lbs. 12-67 74-53 10-34 
 
 The water and loss on the analysis appear to have been 2’46 per cent., and the proportions of the 
 ingredients in the earthy matter is not stated. 
 
 No average increase of volume can be taken, in the present state of our information, to be of any prac- 
 tical utility ; for, 1st, the result depends so much upon the methods employed ; and, 2d, it is not the ag- 
 gregate of the volatile matters which determines the expansion, but chiefly the proportion of oxygen and 
 hydrogen to one another, and also to the earthy matters present. In regard to the first point, Berthier 
 has shown the proportions of volatile matters existing in coke prepared on a large scale for blast- 
 furnaces, to vary from 2-A- to 18 per cent.; in regard to the last, while analysis alone could satisfactorily 
 determine it, yet for the practical purposes of the manufacturer it may be borne in mind that in general 
 great lustre, but deficient hardness and elasticity, indicate the presence of hydrogen, (the element pro- 
 moting fusibility,) while great lustre, with an intensely black color and much hardness, show a predom- 
 inance of oxygen, associated with a large proportion of carbon. These last-mentioned indications, 
 assuming the earthy matter in constant proportion, characterize the class of dry coals, which may be, 
 with more or less advantage, employed raw in the smelting of iron, In general, it may be added, that 
 coals containing more than 20 per cent, of volatile matter cannot be expected, prima facie, to be advan- 
 tageously used in the furnace, either hot or cold blast, without coking. 
 
 From what has been said, it is obvious that the final efficiency of any coke must depend on its ulti- 
 mate constitution. Thus the coke of Luxemburg, just now mentioned, with its 18 per cent, of volatile 
 matter, is substantially but dry coals. The average composition of good coke may be repre- 
 sented as of 
 
 Carbon 82 per cent 
 
 Earthy matters 15 do. 
 
 Volatile matters 3 do 
 
 It is also obvious that the earthy matters in coke answer no useful purpose in smelting — they are only 
 absorbents of heat. In proportion to their occurrence, therefore, they embarrass the operations of the 
 furnace. It is difficult to fix a limit to which there will not be individual exceptions ; but in general, 
 coke containing more than 15 per cent, of ashes is not fit for the iron-master’s use. Karsten places the 
 excluding proportion far lower than this. 
 
 The absolute or relative efficiency of coke, then, can only be determined upon analysis ; and external 
 characters by no means give a conclusive result, though they are often valuable as an approximation. 
 Good coke may be inferred from its not having undergone great alteration of volume , or change of shape ; 
 from its color , an iron-gray, or more nearly that of graphite ; from its lustre , more silky than metallic; 
 from much hardness, elasticity, and resistance to impact ; from a uniform fracture; from a texture more 
 fibrous than compact, and which imparts a peculiar sonorousness to a mass when struck ; and, finally 
 from a specific gravity which should, if any thing, somewhat exceed that of water. 
 
 These details upon fuel may be concluded with the following table, showing the probable consump 
 tion of fuel per 100 of crude non produced with ores of different sorts 
 
96 
 
 IRON. 
 
 Denomination. 
 
 Per centage of 
 Metal in Ore. 
 
 Per centage of Fuel consumed. 
 
 Charcoal. 
 
 Coke. 
 
 Fusible ores, (Class 4, in part, and 5,) 
 
 25 @ 30 
 
 66 @ 90 
 
 no® 150 
 
 do. 
 
 30 “ 35 
 
 90 “ 110 
 
 150 “ 180 
 
 do. 
 
 35 “ 40 
 
 110 “ 130 
 
 180 “ 220 
 
 Ores of mean fusibility, (mixed mines,) 
 
 30 “ 40 
 
 110 “ 140 
 
 180 “ 240 
 
 do. do. 
 
 
 140 “ 180 
 
 240 “ 300 
 
 do. do. 
 
 50 “ CO 
 
 180 “ 210 
 
 300 “ 360 
 
 Refractory ores, (Class 2, 3, and part of 4,) 
 
 30 “ 40 
 
 160 “ 200 
 
 275 “ 350 
 
 do. do 
 
 40 “ 50 
 
 200 “ 250 
 
 350 “ 400 
 
 do. do 
 
 50 “ 60 
 
 250 “ 300 
 
 400 “ 500 
 
 Anthracite lias been omitted in the discussion of fuels, mainly to save room, and also because, in one 
 aspect, it may be considered as coming under the category of coals capable of being used raw in fur 
 naces ; whose employment, (whether bituminous or anthracite,) however interesting to particular dis- 
 tricts, has not yet received actual extension enough to be treated on the ground of uniform or average 
 experience. In another aspect, it may be regarded as belonging to the class of hard-coked coals, whose 
 constitution its own very much resembles, as will appear from the following average, viz. : 
 
 Carbon 88’7 per cent. 
 
 Earthy matters 7 A “ 
 
 Volatile matters 3'9 “ 
 
 It is on the respective proportions of the ingredients in these earthy and volatile matters that its 
 treatment and behavior depend ; the principles of calculation must be precisely the same as those 
 which govern in the case of average coke, and the results accordant. 
 
 2. Ores, and thtir preparation. — The methods of extraction, or mining, practised for different ores, 
 according to differing circumstances of position and association ; of picking, (Fr. triage ,) washing, and 
 stamping, — processes used according to circumstances for separating the ore proper from a more or 
 less indurated gangue, and cleaning it, — will not be considered here ; according to the distribution prac- 
 tised in extensive iron-works, at least, the ores do not come properly under the hand of the furnace- 
 manager until the last of these processes is achieved; and they belong, therefore, to the article Mining, 
 which see. 
 
 The roasting of the ore is the beginning of the furnace processes. The objects of this are to diminish 
 the aggregation of the mass, and thus leave more room for other chemical affinities to act, and for new 
 combinations to take place; to drive off such impurities and admixtures (water, carbonic acid, and sul- 
 phur, principally) as can be volatilized at a red heat; and, as some suppose, to present the mine in a 
 higher state of oxidation. The methods followed should be in subordination to these aims. 
 
 In point of fact, all of them are partly answered with many ores by continued exposure to the at- 
 mosphere, under which a spontaneous disintegration takes place, together with a partial absorption of 
 impurities and a peroxidation. But with some ores, these effects are not manifested till after a long 
 period, (as, for example, with magnetic and specular oxides.) and with all they are vastly accelerated 
 by a due application of heat. It may even be said that all ores are the better for being roasted and 
 then exposed for as long a time as convenient to the macerating influence of the atmosphere. The red 
 hematites of Lancashire are hardly an exception to this ; for, though used habitually raw, it is only for 
 intermixture with other ores, and in small quantity ; while the custom, in some districts, of only weath- 
 ering the sparry carbonates, which are afterwards used unmixed, arises only from the difficulty of so 
 managing the heat as to roast and not fuse them. 
 
 This management of temperature is more or less necessary with all ores. Thus, magnetic and red 
 oxides, quartzose sparry carbonates, argillaceous carbonates containing a suitable proportion of silica, 
 and generally all the silieated ores, are easily vitrifiable. As a general rule, the roasting should be as 
 prolonged and at as low a temperature as possible, with free access of air and moisture. 
 
 The roasting may be done in kilns, or chimps, or ovens. The first is the most simple of all and the 
 most extensively practised. The shape of the kiln is indifferent; it is sometimes conical, sometimes a 
 square or rectangular pyramid. Its size is equally indifferent. The whole method consists in inter- 
 stratifying the or 1 - and fuel, (in an average proportion of about five of the former to one of the latter,) 
 from the base, wheu here is a sufficient accumulation of combustible, and certain rudely made flues 
 or prolonged cavities, to insure the fire taking throughout. The smaller pieces of ore are put outside 
 as a cover, and ashes and cinders, coal, coke, or charcoal dust, or loam, used afterwards, where neces- 
 sary, as a stopper or damper of the fire. After piling and starting the fire, it is. in good weather, only 
 looked at from time to time. In most of the English, Welch, and Scottish furnaces, as well as at 
 many in America, they appear to overlook the importance of keeping a large stock of roasted mine 
 ahead, so as to give it the further benefit of atmospheric exposure. 
 
 Clamps are, in principle, very much the same with those already described for making charcoal. 
 Three sides of a parallelogram, of width and length indefinite, are built round with a dry wall in stone, 
 having draught-holes left at intervals of five or six feet in the base, and carried up to about three feet 
 in height. Chimneys are built loosely, of brick or stone, along the middle of the clamp, and corres- 
 ponding with each one (or, sometimes, two) of the flues. The fuel is laid, in the beginning, at the 
 bottom, and is more or less iuterstratifled with the pile of ore according to the greater or less presumed 
 fusibility of this last. Sometimes there is no interstratification at all, but fuel is supplied as wanted to 
 the draught-holes in the base. 
 
IRON. 
 
 97 
 
 Tho ovens used are of almost infinite variety in shape and dimensions. Their general types are a 
 cylinder, an inverted cone, or a combination of an inverted and a right cone, and a truncated ellipsoid; 
 they vary from 6 to 18 feet in height, with an average diameter of 8 feet at the grate and of 5 to 10 
 feet at the trundle-head. They are like Ihne-kUus, either perpetual or periodic; and, in fact, the de- 
 scription of a lime-kiln is also that of a roasting oven. The temperature to be maintained in the last 
 is lower than in the other. Itcvcrberalory ovens have been tried, but unsatisfactorily, for the roasting 
 of ores. 
 
 It is to be supposed that the larger the oven, the more regular and economical will be the work. For 
 refractory ores, the oval shape is, perhaps, the best ; while the more simple cone or cylinder is better 
 suited to fusible ores. Ores generally pass, with but short (if any) interval, (and in so far disadvanta- 
 geously,) from the ovens.to the top-house, where they are broken up, and immediately charged into the 
 furnace. 
 
 This breaking is effected upon a stone or (better) a cast-iron floor, sometimes with a beetle, one or 
 two handed ; sometimes with iron-shod stampers, moved by machinery ; sometimes the mine is crushed 
 between fluted cylinders made to revolve. But the best of all methods is to break by hand with an 
 ordinary stone-hammer. 
 
 The size to which the mines should be reduced before charging ought to vaiy directly with the hard- 
 ness of the ore and the height of the furnace. From one to three inches, average diameter, inside, will 
 be the limits. Larger than the one, they leave too much to be done in the furnace ; smaller than the 
 other, they embarrass the blast. 
 
 3. Fluxes. — The reducing effect of the carbon of the fuel upon the metallic oxides in the high-furnace 
 has been already spoken of, as well as that of the potassa and soda contained in the earthy matter of 
 charcoal ; but these are rarely sufficient, with most mines, to cause at once fusion and reduction ; and 
 it becomes necessary, then, to add other matters, sterile in metal, to promote fusion : these are known 
 as Jinxes. Silica, indeed, which is a constant association in all ores of iron, is, of itself, a sufficient flux 
 in some cases ; but, even in those, it is more apt to be in excess, when it both embarrasses the working 
 of the furnace and impairs the quality of the metal. It would be proper, then, to neutralize this excess 
 by the addition of some other substance ; and such addition becomes still more proper when (the prac- 
 tical problem in the furnace being to effect fusion at the lowest possible temperature ) both theory and 
 experiment show that it not only cures such excess, but also promotes fusibihty. In fact, we know 
 that while of each of the earthy bases most ordinarily accessible, viz., silica, lime, magnesia, and alumina, 
 is almost (and one of them entirely) infusible, per se, yet in combination, two and two, three and three, 
 and, still more, four and four, they melt readily at easily attainable temperatures. The addition, then, 
 of suitable proportions of these sterile matters, is the means to economical fusion of the materials in the 
 furnace. 
 
 Without dwelling, however, upon the theory of their action, (which has been explored more or less 
 profoundly by a host of chemists and metallurgists, and has been experimentally examined by Achard, 
 Alexander, Berthier, Descotils, and Lampadius,) and regarding only the practical maxims that fit the 
 question, it may be said that in addition to the silica and alumina, always present in the ores and fuel, 
 and to the lime, magnesia, manganese, and potassa, sometimes present, too, the positive flux most usu- 
 ally added is lime, in the form of marine shells, limestone, or chalk. The proportion of this addition 
 varies in almost every case ; but, at a mean, it may be taken, for charcoal furnaces, at one-fourteenth of 
 the other solid materials by weight; and at one-eighth, for coke furnaces. 
 
 Although lime is the flux thus almost universally employed, it is not always the one that best suits 
 the case. With an excess of silica, it is the proper one. But when the ores are themselves calcareous 
 in any considerable degree, the best addition is of aluminous or magnesian earth, or both. In some 
 cases, where the ores and fuel are highly aluminous, the addition required (though with great caution) 
 is silica, in the shape of quartz, itc. In such cases, the best avail has been taken of siliceous matter 
 containing also a low proportion of iron. It is thus that amphibole, basalt, and garnet have been ap- 
 plied. This is, in fact, the use of a poor material instead of one utterly sterile. 
 
 In general, it may be estimated, that of the whole solid materials introduced into the furnace, (tire 
 metallic iron excepted,) the 
 
 Silica may range from 45 to 60 per 100. 
 
 Lime “ 20 to 35 “ 
 
 Alumina “ 12 to 15 “ 
 
 Magnesia “ 12 to 25 “ 
 
 Oxide of manganese 15 to 20 “ 
 
 If all four first named are present together at once, the most fusible proportions in which they can 
 exist (without regard to the fluxing action of metallic oxides that may be there too) are, 
 
 Silica 35’2 per 100. j Lime 19T per 100. 
 
 The solid material of the fluxes should be, like the ores, broken up into fragments of similar and uni 
 form size. When oyster-shells are used, it is not necessary to treat them further than by a slight pre- 
 vious calcination. They do not always receive that. 
 
 The artificial fluxes, (such as salt, potash, saltpetre, &c.,) either singly or in combination with alkaline 
 earths, which have been suggested at various times in the last twenty years, do not appear to have met 
 with as much practical success as the theories of those who recommended them seemed to warrant. It 
 is probable that this will be always the result ; owing not so much to mistake in the principle as to a 
 difficulty, inherent in the blast-furnace, of applying these highly fusible and reducing agents just at the 
 point where they are wanted. 
 
 4. Gaseous material — atmospheric air. — The remaining material in blast-furnaces, besides those tha 
 have been considered, is the atmospheric air, which is regularly blown in to keep up the combustion. 
 
 Vol. II. — 7 
 
IRON. 
 
 y* 
 
 It is, therefore, in this aspect, one of the most important to be duly managed ; and when the enormous 
 quantities of it that are required are taken into view, its probable influence and collateral effect can be 
 still better appreciated. The following average statement may be derived from the practice in this 
 particular. 
 
 Charcoal Furnaces. Coke Furnaces. 
 
 Solid. Gaseous, Solid. Gaseous. 
 
 Volume of materials, in cubic feet, per minute 0 295 900' 1'06 3000. 
 
 do. proportionate I 1 3050' 1' 2830- 
 
 Weight of materials, in lbs., per minute 24-82 15' 102-12 269- 
 
 do. proportionate 1- 3-022 1- 2'634. 
 
 Taking the mean of the proportional quantities, it appears that, in round numbers, the vci'jr.ie of the 
 air injected is 3000 times larger than that of all the solid materials in any given time ; while its weight 
 is three times greater than theirs. The elements used above would show also that on the average there 
 is consumed nineteen tons of air for one ton of iron made. 
 
 In order to illustrate the means of managing this vast supply, Fig. 2365 (a sketch, with more atten- 
 tion to distinctness than proportion of parts) 
 
 -. ■■■■■ ■ ^ 
 
 shows the arrangements suitable for a furnace 
 of the first class. The power used is assumed 
 to be steam; though the method of its pro- 
 curement and application is not carried further 
 back here than to the steam-cylinder c, worked 
 horizontally by the same piston-rod that goes 
 turough and works the cylindrical bellows b. 
 
 It is obvious that other sources of power, or 
 other methods of geering, may, under suitable 
 circumstances, be resorted to. From b, the 
 bellows, the air is driven into r, the regulator, 
 whence it passes into a a , the furnaces for heat- 
 ing it, and then transmitting it along 1 1 into h, 
 the hearth or crucible. T indicates the tymp- 
 
 arch as before ; W a retaining wall against the hill-side, and connected by an arched bridge above with 
 the stack ; wdiile the blanks left in the piers show the passage-ways before spoken of, left for more 
 convenient access between the tuyfere and tymp-arches. Such being the general arrangements, the 
 parts and their requisites will be spoken of briefly in order. 
 
 Bellows, or blowing machines, have been constructed of leather, of wood, of stone, and of cast-iron. 
 The first material, on account of its expensiveness and the narrow limits which it imposed upon both the 
 volume and density of the blast, is no longer used except for smiths’ fires. The second, whether made 
 with hinges or (as afterwards) worked with a piston, left much to be desired. The use of the third, in 
 an instance or two, can only be justified by necessity, or applauded as a conquest over circumstances: 
 while the last, in the shape of a double-acting cylinder, furnishes the only satisfactory and sound 
 means to the end. 
 
 Before describing these, however, mention must be made of a method on a totally different principle, 
 which, under variously modified forms, is still employed in parts of Italy and the districts of the Pyrenees. 
 This is the trompe or water-blast, of which Fig. 2366 shows the principle. 
 
 In this, a vertical tube of wmod or iron, 
 
 cylindrical or prismatic, of length and 23CC - 
 
 diameter suited to the fall and quantity 
 of water intended to be used, connects 
 with a cistern below, made air-tight ex- 
 cept for the opening t, to connect with the 
 tuyere. Through this tube a stream of 
 water is allowed to fall, drawing in the 
 air as it descends through openings that 
 are indicated by broken lines in the sides 
 of the column, and breaking upon an altar 
 below. The air thus carried into the cis- 
 tern has no means of escape except the 
 luyfere t, and its quantity and pressure 
 delivered through that depends upon the 
 absolute size of the column of water, and 
 the proportions of the various parts. Ven- 
 turi has already satisfactorily investigated 
 the relations of this machine ; wdiich will 
 not be dwelt on in that aspect further 
 here than to say, that although very cheap 
 and convenient in its construction, it uses 
 more water for a given effect than a 
 water-wheel would do, and that its effec- 
 tiveness is quite limited. Karsten refuses 
 to admit that the dampness of the blast 
 it affords, injures the quality of the iron ; 
 although it is probable that most metallurgists would conclude, in the face of general theory and expo 
 rience, that the good quality of iron made by this method exists in spite of it. 
 
IRON. 
 
 90 
 
 2367 
 
 The chain-blower of Henschel is an improvement upon this machine. In it, a more complete separ- 
 ation of the air and water is effected, by means of an endless chain of floats or pistons, worked by the 
 descending water itself; but its effect is not such as to take it out of the general category of objections. 
 
 Tire hydraulic bellows of Baader is, in fact, but a single-acting piston air-pump, in which the surface 
 of a reservoir of water is made to take the place of the otherwise solid end of the pump. It cannot be 
 made to furnish blast either of large volume or much density, and is mentioned here only because it is 
 actually used with satisfactory effect in suitable cases ; but it can only be recommended in districts 
 where water is plenty and the labor of the artisan dear. 
 
 The oscillating cylinders of D’ Aubuisson are an extremely ingenious blowing-machine, cheap to con 
 struct, and worked with little power and at small expense. Although 
 not giving a blast of sufficient amount or density for the smallest liigh- 
 furnace, except with the most fusible materials, they answer very well for 
 chafery and finery fires. Fig. 2367, which is a section of one of the cylin- 
 ders, will afford an illustration of their action. A diaphragm, central, 
 through the entire length and nearly the whole diameter, is shown at erf; 
 v v are two valves, alternately aspiring and expiring. In its normal posi- 
 tion d d is vertical ; the barrel is filled half full of water, through a bung, 
 and is then set in oscillation, through an arc of 90 or 100 degrees, by a 
 connecting-rod and crank geered on near c. It is manifest, that in differ- 
 ent angular positions of the diaphragm the content of water in the two 
 semi-cylinders will come to be unequal, as shown by the shaded lines ; 
 and the air will be respectively rarefied and condensed accordingly. 
 
 All these methods, however, imply more or less contact of the air with water, and the consequent 
 immission of more or less moisture with the blast ; which is objectionable. But this oscillating method 
 leads to speak of a rotary method for delivering dry air — at least, air of the ordinary atmospheric hu- 
 midity only. This last is the fan-blast, in which fans, radiating from an axis, are caused to revolve 
 rapidly in an appropriate disk, receiving the air at the centre of rotation, and delivering it on the cir- 
 cumference into a chest, with or without a valve. The volume of air furnished by this means is not, 
 without considerable expense in construction and power, sufficient for a high-furnace of the first, or even 
 of the second class ; but the density that can be obtained leaves nothing to desire. For cupolas, re- 
 fineries, &.C., it is very convenient and appropriate. It is, in practice, of two kinds : one acting impul- 
 sively, in which the air is aspired and at once diffused in a common chamber, whence it is driven out by 
 the fan-wheel ; the other centrifugally, in which the fan itself is a hollow wheel, receiving the air at 
 openings near its axis, discharging it first, at openings in its circumference, into the chamber or casing, 
 and then driving it out from said chamber by fans fixed upon its own periphery. The chamber of the 
 outer casing is kept from communicating with the external air, as it is inspired, by a portion of the 
 internal revolving disk, which is made to work air-tight as possible in the outer casing. Here is exactly 
 the embarrassment of the arrangement, which imposes a higher cost upon the apparatus in the begin- 
 ning, and is difficult of maintenance. When it fails of being maintained, however, the machine does 
 not, on that account, lose its value — it merely passes over into the other class. 
 
 Fig. 2368 is a section of a horizontal, double-acting, blowing-cylinder, in cast-iron ; which may be taken 
 as the type of a class that fulfils all desirable conditions. The details, it is supposed, sufficiently ex- 
 plain themselves. There are some advantages in a horizontal cylinder rather than a vertical one ; 
 principally, it can more readily secure a good foundation, with less waste room from valves, which, in 
 the others, are more or less necessarily in the sides. By carrying the piston-rod through both heads, 
 the weight of the piston is equalized upon the collars, and there is left but little risk of the cylinder's 
 wearing out of shape. 
 
 The size of the blowing -cylinder depends upon the volume of blast wanted. As the length of the 
 stroke is generally somewhat limited by the conditions of the other machinery which supplies the 
 moving power to the piston, and as the maximum speed of the stroke, or number of revolutions in a 
 given time, is, in like manner, determined by general mechanical considerations, it has been found 
 necessary, in practice, to give these cylinders a large diameter, disproportionate to the length of stroke 
 
IRON. 
 
 LOO 
 
 'The blowing-cylinder at Dowlais, for instance, (which is the most extreme case that could be cited,) has 
 a stroke of 10 feet and a diameter of 12 feet. 
 
 To determine the volume of blast, and, consequently, the size of cylinder, the best rule is, when the 
 constitution of the materials to be used is known, to allow air enough to pcroxidate all the materials in 
 the furnace at any one moment. This will be the outside limit. In ordinary practice, the machinery 
 will be worked at a slower speed ; and in emergencies, there will be still a margin to go upon. In 
 calculating the supply of air, it is to be remembered that the best-executed blowing machines do not 
 deliver into the furnace more than J of their theoretical capacity : it would be even safer to take, as an 
 average, J of such capacity for the actual supply. 
 
 If the constitution of the materials is not known, but the size of the furnace is, and thence the num- 
 ber of charges that it ought to bear in a turn, we have another rule : One fifth of the weight in 
 pounds of fuel (either charcoal or coke) charged during one turn of twelve hours , is the number of cubit 
 feet of air, under the pressure of the atmosphere , to be furnished in one minute. 
 
 This allows for the average discount on the working of the machine, leakage of pipes, &c. ; and gives, 
 therefore, at once the capacity of the cylinder. 
 
 Regulators are of two general classes : 1st, of variable capacity ; and, 2d, of constant capacity. Those 
 of the first class are either dry, or wet, or (as these last are called) water-regulators. l)ry regulators 
 are merely cylindrical air-chambers, in which a piston works air-tight, which is loaded to the pressure 
 desired at any time. These cylinders have, of course, an inlet and an outlet pipe for the air, neither of 
 which needs valves : the valves shown in the air-chest above the cylinder, in Fig. 2368, answer all the 
 purpose of isolating the air in the regulator from that under the piston, on the one hand, while, on the 
 other, the blast-pipes and tuyeres are regarded but as continuations of the regulator. In fact, in every 
 case, long and large blast-pipes (although density is lost in proportion to length) serve, in a measure, 
 to assist in uniformity of blast. The capacity of these dry regulators should be, in theory, twice the 
 capacity of the blowing-cylinder ; in practice, they will answer to be one u:id a half times as large. 
 
 Water-regulators are oblong chests without a bottom, or receivers, let down in a tank containing 
 water, and balanced after the manner of gasometers. The weight of the chest, and the additional load 
 put upon it, cause it to sink ; the influx of the air, and its elasticity, cause it to rise, /is the air be- 
 neath the piston is under much greater pressure than in the regulator, and thus every stroke of the 
 piston causes a slight fluctuation, the capacity of these regulators (whose minimum is the same as in 
 the former kind) is generally governed by other considerations, and made as great as convenient. The 
 adjutages and pipes for receiving and discharging the blast are, in practice, very much varied in po- 
 sition, &c. ; but the general principles of their arrangement are too obvious to require description here. 
 Very convenient and suitable in most regards, this kind of regulators is liable to all the objections ac 
 cruing from access of moisture. 
 
 The second great class comprehends air-chambers of constant capacity. These, which long ago were 
 built under or above ground in masonry, or for which even subterranean caverns, sedulously rendered 
 air-tight, were resorted to, have, in the most modern times, come up again, (as in Wales,) only in a 
 material more suitable and manageable. Sheet-iron is now most generally resorted to ; strengthened, 
 when thought necessary, with ties. Their form is generally cylindrical or spherical ; one of the latter 
 shape exists with the enormous diameter of 25 J feet. The most convenient form appears to be that of 
 a right cylinder, of thin sheet-iron ; with a base solidly supported, and a head, either of cast-iron or 
 sheet-iron, stiffened with wood, carrying a safety-valve, (which acts here also as an equalizer of pres- 
 sure,) and admitting of an aperture, large enough for the entrance of a workman, and capable of being 
 closed air-tight. 
 
 Of course, the larger such a chamber is, the less will it feel the pulsations of the piston ; but there 
 must be an economical limit in this respect. In practice, the regulator is made from nine to fifteen 
 times as large as the blowing-cylinder ; in theory, its least capacity, to furnish a uniform discharge, 
 should be in the same proportion to the blowing-cylinder as the pressure of one atmosphere is to the 
 pressure desired to be maintained. Thus, if the pressure be assumed at 2 lbs. per square inch, the reg- 
 ulator must be at least V 5 or 7 J times the size of the blowing-cylinder. 
 
 From the regulator the blast-pipes were traced, in Fig. 2365, to the hot-air furnaces ; but the consid- 
 erations belonging to these will be postponed for a moment, and the furnace considered as working (as 
 all did, in fact, until 1827, the epoch of Mr. Neilson’s improvement, and as many prefer to do still) 
 with cold-blast. What remains to he spoken of in advance is the blast-pipes and nozzles ; the water- 
 tuydres, which are indispensable with hot air, and advantageous with cold-blast, have been already 
 mentioned. 
 
 Blast-pipes are made of sheet or cast iron ; for first-class furnaces, where the pressure is required to 
 be considerable, generally of the last-named material. As they cannot be made in one piece, they are 
 jointed either by flanges or by a muff, (what is called the faucet aud spigot joint,) as in gas and water 
 pipes. When cold air is employed, the packing of the joints is lead; with hot air, an iron cement must 
 be used. This cement is made of 99 parts of iron filings, sifted fine, and 1 part of powdered sal am- 
 noniac, intimately mixed, dry. When used, as much water is added as will make a stiff paste. Flow- 
 ers of sulphur, sometimes recommended, in no way contributes to the efficiency of the mixture, but 
 rather to the contrary. 
 
 The pipes are sometimes laid under ground and covered over ; hut this mode is not to be recom- 
 mended ; they should be always accessible. If hot air is ever expected to be used, provision should 
 be made in the laying for expansion and contraction by resting them upon rollers, (short pieces of 
 three-inch iron pipe answer very well,) on a smooth foundation. It is impossible, in the conditions of 
 application, to avoid flexures ; but these flexures should, of course, to save friction, be made as gentle 
 as possible. 
 
 When the straight lengths are so great that there appears to be danger that the pipe will break, a 
 
IRON. 
 
 101 
 
 compensation-joint is inserted ; this frequently consists of an end of 
 a pipe movable in a stuffing box. The plan represented in fig, 
 2371 is preferable to it. This is a compensation-joint, consisting of 
 two round dishes of sheet-iron, or copper, 20 or 30 inches in diam- 
 eter, according to the size of the pipe, riveted air-tight at their 
 periphery, and screwed to the two flanges of joining pipes. The 
 sheet iron may be from ^ to of an inch thick. The large diam- 
 eter and flexibility of the sheet-iron allow the two pipes which arc 
 joined to it, to move longitudinally, independent of each other. 
 Wooden blast pipes are sometimes used, but are useless where a dense 
 blast is to be conducted. 
 
 The capacity of the pipes, i. e. their diameter, should, other things being equal, be as large as possible. 
 But, as other things (to wit, the expense) are not equal, they should be proportioned to the quantity of 
 blast to be delivered. A reasonable unit may be taken, in allowing a nine-inch pipe to 1000 cubic feet 
 of blast per minute. Then, as the quantities vary with the squares of the diameters, 4000 cubic feet 
 per minute will be accommodated by pipes of eighteen inches. 
 
 Whether the pipes are laid under or on the ground, the level of the tuybre will still be above them ; 
 two elbows, therefore, are necessary to bring the nozzle into the tuydre. The junction of these elbow- 
 pieces should be always with a ball and socket joint for giving play tc the nozzle. With cold-blast, 
 this play can be, and frequently is, attained upon fixed elbows, by connecting the nozzle and the blast 
 pipe proper with a leather hose or bag ; with hot-blast, the leather is inadmissible. 
 
 Various forms, of more or less complexity, are used in and about the termination of the pipes for 
 shutting off the blast entirely (as has to be done at every run-out) or partially, measuring its intensity, 
 <tc. Pig. 2372 shows one of the most simple and satisfactory. The ball and socket and fixed elbow 
 
 ioints are both seen. At v is a trundle-valve of sheet-iron, elliptical in shape, with alternately bevelled 
 edges, and worked by the winch above. When this winch is parallel with the axis of the pipe, the 
 valve presents nothing but its thickness to the blast ; when it is at right angles to the axis, it shuts up 
 the pipe entirely, and with a tightness proportionate to the accuracy of its fitting. It can be made (so 
 to speak) perfectly tight. Some furnace-managers have a plate-collar fastened beneath the winch, 
 divided angularly on its circumference, and read by an index that moves with the winch, to show either 
 the absolute or relative quantities of blast in the different positions of the winch-handle. At e is an eye- 
 let, closed ordinarily with a conical iron plug, as shown. When this plug is out it allows the founder 
 to look into the hearth and observe the aspect of the tuyere. With hot air, this has to be used dis- 
 creetly. Between the valve and the elbow, somewhere about m, is placed (with cold-blast) the ma- 
 nometer or pressure - meter of the blast. Fig. 2373 shows a section of the pipe with the apparatus at- 
 tached ; which is only a glass tube, | inch bore, containing a few inches of quicksilver, and open at both 
 ends. When there is no pressure from within, as when the blowing-machine is at rest or the blast shut 
 off, the mercury stands, of course, at the same level in the two branches of the tube ; when there is 
 pressure, the column in the long arm rises, at the rate of 1 inch in height for every lb. of pressure. 
 The best scale to put on it is a piece of card, divided in equal parts, sliding up and down by friction, 
 and capable at any moment, by shutting of the valve, of proper adjustment. With hot-blast, the ma- 
 nometer has to be placed in the regulator. Otherwise the actual density of the air is more accurately 
 measured as near as possible to the nozzle. 
 
 These nozzles or adjutages are conical sheet-iron tubes, made to fit as tight as possible upon the cy- 
 lindrical blast-pipe, and tapering off to an orifice from 1 to 5 inches, in diameter. Furnace-managers do 
 not generally trouble themselves much about the laws of pneumatics, and hence we find a great variety 
 in the shape and proportions of these utensils. Several of them are provided of larger and smaller 
 orifices, to be used as circumstances require. Ordinarily they are in two joints, of which the one fitted 
 to the blast-pipe is the more permanent. The elliptical shape of the orifice sometimes found, is a dis- 
 advantage, as well as the great length of the cone ; both lessen the discharge that would follow a shorter 
 and more acute cone. The following table (which is strictly accurate under the conditions for which it 
 was calculated) is sufficiently so to be relied on for giving the discharge of blast into a furnace in any 
 case likely to occur, the pressure being that in the regulator, and the diameter of nozzle being measured 
 at the extreme point of discharge. 
 
 A table like this is indispensable to a furnace-manager who wishes to be cognizant of what is going 
 on in the furnace, in connection with changes, accidental or designed, in the blast. Its application in 
 the present shape is both direct and inverse, and in either method is very simple. Thus, having ascer- 
 tained the actual pressure of the blast to be, say 1-J lbs., while we are using a nozzle of 2 inches ; if we 
 wish to know directly what is the quantity actually going into the furnace, we enter the table, under 
 the first column, and opposite to that we find 122'61 cubic feet, which is the quantity that would pass 
 through a 1-inch nozzle. Then, as the areas of circles are as the squares of their diameters, the quantity 
 
102 
 
 IRON. 
 
 passing through a 2-inch nozzle will be four times as great as through a 1-inch ; therefore the quantity 
 in question will be 122'61 X 4 = 49044 cubic feet per minute, through one tuyere. If the furnace has 
 two tuyeres with the same sized nozzle, the whole quantity discharged in one minute will be, then, 
 98088 cubic feet. We have, then, as a general rule, to enter the first column of the table for the given 
 pressure, ranging with which, in the second, is a number that, multiplied by the square of the diameter 
 of nozzle used, will give the actual quantity blown in by the single tuyere. 
 
 It may be applied, again, inversely, to find the diameter of nozzle that will discharge any required 
 quantity per minute under a given pressure. Thus, if the question be, what diameter of nozzle will 
 keep up a pressure of 1 lb. on a discharge of 800 cubic feet per minute through one tuyere ? — we havo 
 only to divide 800 by the number (10T66) standing in the second column opposite the given pressure; 
 
 the square root of tire quotient 
 
 or 2 t 8 j inches is the diameter sought. 
 
 Table shoiving the Volume and Weight of Blast discharged under various Pressures and at ordinary 
 
 Temperatures. 
 
 Pressure per 
 square inch. 
 
 Quantity in cubic 
 feet per minute, 
 through a 1-inch 
 nozzle. 
 
 Weight in lbs. 
 per minute. 
 
 Pressure per 
 square inch. 
 
 Quantity in cubic 
 feet per minute, 
 through a 1-inch 
 nozzle. 
 
 Weight in lbs. 
 per minute. 
 
 4 oz. aVd. 
 
 18-54 
 
 1-43 
 
 2 lbs. avd. 
 
 139-48 
 
 12.14 
 
 1 “ “ 
 
 26-20 
 
 202 
 
 24 
 
 ti 
 
 146-86 
 
 12-97 
 
 2 “ “ 
 
 36-97 
 
 2-86 
 
 2-J- 
 
 U 
 
 153-70 
 
 13-77 
 
 4 “ “ 
 
 52-07 
 
 4-07 
 
 2| 
 
 it 
 
 160-06 
 
 1455 
 
 6 “ “ 
 
 63-51 
 
 5- 
 
 3 
 
 it 
 
 106-01 
 
 15-30 
 
 8 “or 4 lb. 
 
 73-04 
 
 5-80 
 
 34 
 
 a 
 
 171-61 
 
 16-03 
 
 10 “ av’d. 
 
 81-33 
 
 6-51 
 
 34 
 
 u 
 
 176.88 
 
 16-75 
 
 12 “ “ 
 
 88-74 
 
 7-16 
 
 H 
 
 a 
 
 18T86 
 
 17-46 
 
 14 “ ■' 
 
 95-47 
 
 7-76 
 
 4 
 
 u 
 
 186-58 
 
 18-15 
 
 1 lb. “ 
 
 101-66 
 
 8-33 
 
 44 
 
 a 
 
 191-07 
 
 18-83 
 
 14 “ “ 
 
 112-78 
 
 9 38 
 
 44 
 
 a 
 
 195-35 
 
 19-50 
 
 14 “ “ 
 
 122-61 
 
 10-36 
 
 4J 
 
 a 
 
 199-43 
 
 20-17 
 
 H “ “ 
 
 13T44 
 
 11-27 
 
 5 
 
 a 
 
 203-32 
 
 20-82 
 
 If, instead of measuring the discharge by volume, we have occasion to know the weight of the bloat, 
 {he third column, treated in the same manner, gives that element. 
 
 2374. 
 
 2375. 
 
 The effects of a more or less dense blast, i. e. of more or less pressure, appear to take place in two 
 ways principally. First, mechanically upon the quantity of discharge in the same time ; and, secondly, 
 chemically upon its constitution, and upon the materials in the furnace. The air, at the instant of ex- 
 piring, is of the density it had in the blast-pipe, although it very shortly afterwards assumes its normal 
 
IRON. 
 
 10? 
 
 volume. But as far as the melted materials in the hearth are concerned, it is, at the moment of entry 
 richer in oxygen in proportion to its density. Thus, under 
 
 Pressure of Volume of air. Weight in oxygen, 
 
 lib. 100 cubic feet give T88 lbs. 
 
 2 “ do. do 2' “ 
 
 3 “ do. do 2T2 “ 
 
 By increasing the pressure , then, we support combustion more readily, and generate a rn intense 
 degree of heat. By augmenting volume , we support combustion more extensively, and produce a greater 
 quantity of heat. These considerations apply to and solve the question often mooted among founders, 
 as to whether the best effect is obtained by increasing the pillar of blast, (as they term it,) or using 
 larger nozzles, and thus furnishing more air under a constant pressure. With fusible materials, suffi- 
 cient air should be furnished under low pressure ; with refractory ones, it is better to increase pressure 
 rather than volume. 
 
 The apparatus used for heating the blast is very varied and multiform, the aim being in all to furnish 
 the utmost extent of heating surface with the greatest economy. Instead of mentioning all the modifi- 
 cations that have been suggested, or figuring the contortions that hot-air pipes have been made to 
 exhibit, Figs. 2314 and 23*75 give vertical sections, transverse and longitudinal, and Fig. 2316 a horizon- 
 tal section of the most convenient and best arrangement, either for separate furnaces near the tuyeres, 
 or for ovens on the trundle-head. In the latter case, the 
 horizontal flue shown in Fig. 2316 (which communicates with 
 a vertical one in the stack itself, or back-wall) is replaced 
 by a short chimney. So far as outlay is concerned, to heat 
 the air at the trundle-head is the cheapest, for there is no 
 extra fuel required. But to realize all the benefits of the 
 system and the greatest absolute economy, separate furnaces 
 below are much preferable. 
 
 For the dimensions to be given, in either case, iron-masters 
 are yet without any rule, not so much from any difficulty in 
 investigating the principles that should govern, as from want 
 of actual experimental knowledge on the rate of cooling, Ac., 
 which prevents any general formula from being applied. 
 
 Calculations made upon the quantities and velocities of blast under pressures between the ordinary 
 limits, (of ll to 2-J pounds per square inch,) result in 18 and 28 square inches respectively of heating 
 sui'face for every cubic foot of air per minute. The mean of these, or the l-6th of a square foot, may be 
 taken as a safe allowance (if the pressure does not exceed 2-J pounds) for raising the temperature of the 
 air, at the instant of leaving the oven, to half that of the pipes. What will be its temperature at the 
 nozzle depends upon the distance it has to go, the thickness and size of pipes, <fcc. With a higher pres- 
 sure than 2 ^ pounds, the heating surface ought to be enlarged directly in proportion, at least ; for in the 
 very fact of being heated the air acquires a great increase of velocity, and therefore is exj>osed so much 
 shorter time in the heated pipes. 
 
 There are a number of interesting points, chemical and mechanical, in the employment of hot-blast, 
 for which there is no room here. All that can be said is, that, in general, with hot-blast the furnace 
 works easier, carries a greater burden, with, of course, a higher yield, and reduces materials too refrac- 
 tory for cold air. A notable economy of fuel and flux follows. With regard to the former, the saving 
 of fuel, upon an extensive comparison of results, may be stated for 
 
 Coke-furnaces at 32 per cent., from an average temperature of 330° F. 
 
 Charcoal do. 20 do. do. do. 390° F. 
 
 Besides this, certain raw coals that would not be admissible with cold-blast, are capable of being used 
 with hot. 
 
 As to the quality of metal made, it is generally gray foundry-iron, with a more uniformly cubic crys- 
 talline form than cold-blast foundry. There is a general prejudice against it, as being less strong, but 
 this opinion is more exaggerated than actual experiments warrant. The following table shows the pro- 
 portionate strength in various aspects, from numerous trials : — 
 
 Resistance to 
 
 Transverse or 
 
 Stretching strain. Crushing strain, oblique strains. Impact. Stiffness. 
 
 Cold-blast iron 1000 1000 1000 1000 1000 
 
 Hot-blast iron 913 1033 963 1005 935 
 
 These statements upon the quality of metal lead naturally to the next class of considerations, which 
 must be taken up, viz., upon the products of the blast-furnace. 
 
 These products are, like the materials, both solid and gaseous. To the former belong the crude iron 
 and the furnace-cinder, as the melted slag of earthy matters is termed; to the other the various ele- 
 mentary and compound gases which arise from combustion and decomposition, and pass olf at tire 
 trundle-head. 
 
 The first solid product, the crude iron, has been already sufficiently treated of ; the other, the cinder, 
 is reciprocal with it, and is one of the important tests which the founder has in judging of the progress 
 of his work and of the issue that he may reasonably expect. 
 
 Furnace-cinder, chemically, is chiefly a silicate of lime in various proportions. In charcoal works it 
 is a bisilioate, in coke-furnaces a single silicate. This appears from the following statement, which rep- 
 resents the average of good cinder, i. e., when the furnace is doing good work : — 
 
 2370. 
 
104 
 
 IRON. 
 
 
 Char-coal cinder. 
 
 Coke cinder. 
 
 Silica 
 
 53 
 
 43 
 
 Lime 
 
 22 
 
 35 
 
 Alumina 
 
 
 14 
 
 Magnesia 
 
 5 
 
 4 
 
 Protoxide of iron 
 
 4 
 
 4 
 
 The charcoal cinder is, in its proportions, a more fusible compound than the other ; but abstract 
 fusibility is not so much to be considered as fusibility at the temperature employed. Coke-furnaces, 
 having a higher temperature, require a more refractory material, in order that the cinder may answer 
 its proper uses. 
 
 These uses, in general, are to assist in fusion and reduction; with very fusible ores, to retard fusion 
 until the deoxidation of the metal has occurred ; and after reduction, to protect the metal in the hearth 
 from contact with the blast. In this last aspect, especially, the degree of fusibility of the cinder is of 
 great practical importance. If it be too thick and pasty, it embarrasses the separation of the metal ; 
 if it be too thin and liquid, the iron is exposed naked to the blast. These properties, as they may exist 
 within the furnace, are judged of by the consistency of the cinder during its flow. If liquid enough to 
 flow readily over the dam-plate, and slowly cooling afterwards, it is of the proper character; but what- 
 ever its liquidity may be, if it tends to cool rapidly, the presence of metallic associations is to be inferred. 
 Such association, as far as iron is concerned, may be inferred also from its color, which, with an admix- 
 ture of iron in notable proportions, is always brownish or black. The most satisfactory color for the 
 mass, on a fresh fracture, is whitish gray. Blue and bluish-green shades and streaks are almost always 
 to be met with. The proper way to judge of color, however, is only upon a pulverized specimen. The 
 fracture of cinder is always conchoidal, and its specific gravity, at a mean, 2'6. The aspect of good 
 cinder, from charcoal works, is glassy ; from coke-furnaces, it is more lithoid, or stone-like. When cin- 
 der becomes earf/ty-looking, it argues deficiency of heat ; and if the furnace on the preceding cast has 
 given gray iron, more blast may be put on without fear, — if white iron, the blast should be augmented 
 cautiously. A cavernous or honeycombed cinder appears to originate in the same defect of heat ; while 
 one like enamel, although by many founders attributed to the same cause, arises more from elements in 
 the materials — chiefly phosphate of lime. 
 
 The gaseous products of the furnace may be taken to consist, on an average, of 
 
 Nitrogen 56 Carburetted hydrogen 2 
 
 Carbonic acid-. 19 Vapor of water 7 
 
 Carbonic oxide 16 
 
 The watery vapor most likely arises from the moisture of the materials freshly put in, and is, therefore, 
 hardly a product. If the fuel had all been fully consumed, the sole products would be nitrogen and 
 carbonic acid. But this full combustion has not been, and, with the methods followed, cannot be 
 attained. 
 
 These gases, as they are, pass off at the trundle-head at a high temperature ; so high, that the oxy 
 and hydro carbon combine there with the oxygen of the atmosphere and inflame. This flame furnishes, 
 among other things, a sign to the founder of the state of the furnace. If it is small and weak, it is pre- 
 sumable that the blast does not pass through sufficiently ; and the materials, which from the moment 
 of charging ought to be undergoing a preparation for fusion, are in fact descending more or less raw. 
 The remedy for this is not always to increase the blast ; on the contrary, a discreet founder will first 
 take into consideration the nature of the materials, their friability, and liability to become packed in the 
 cuvette. Too little slope to the boshes, too, is always more or less involved in the result, where the 
 materials are constant. 
 
 If the flame is, as sometimes, on one side, it is a sign that the charges are not descending equally. 
 If this is permanent, there is reason to suppose that the in-walls or boshes, or both, have degraded out 
 of shape. If occasional, it is rather to be attributed to an accidental choking of the furnace, caused either 
 by a bad state of materials, or, what is more common, bad filling. Of course, the flaring from atmos- 
 pheric causes must not be confounded with this phenomenon. In a well-going furnace and a calm at- 
 mosphere the flame should rise cylindrically, with life, and with a certain whistling cry the founder 
 likes to hear. 
 
 A fame at the tymp is a sign that the blast is not going in the right direction ; in this case, it is better 
 to alter the charges, by putting on less mine, than to change the blast. 
 
 The high temperature at which the gases pass off at the trundle-head is an unavoidable consequence 
 of the process ; it is, nevertheless, waste-heat. This waste-heat has been turned to account, as already 
 mentioned, in the case of hot-blast. It has also been used for burning lime, for carbonizing wood, fur 
 coking, and for generating steam. For all these purposes, except the first and last, it is rarely conve- 
 nient to apply the inflamed gases ; and as, in leading off to a distance what is only inflammable air 
 there is more or less loss of heat, these applications have been limited. For roasting ores, it is a per 
 fectly appropriate means. 
 
 M. Faber du Faure, as far back as 1837, conceived and very ingeniously executed a very brilliant 
 idea of leading off the gases, without contact of air at first, to suitable points where, by mixing it with 
 highly heated atmospheric air, it could be burnt, and the heat thus produced applied not only to the 
 generation of steam, but also to other processes (refining, puddling, and reheating) in the manufacture of 
 the crude iron yielded from the blast-furnace. The progress of his experiments led to investigations upon 
 the actual constitution of the gases at different points of the stack ; and to the conclusion that the oxide 
 of carbon existed as a maximum at a level below the trundle head, about one-third of the height of the 
 stack. About this level, therefore, one or more flues are made in the stack, through which the gas 
 ascends into a reservoir around the trundle-head, whence conduits of masonry or metal take it off into 
 
IRON. 
 
 105 
 
 in air-chest ; from which, after mixture with a hot-blast, it issues through a suitable number of nozzles 
 or burners into the hearth where it is destined to be burned. 
 
 This discovery and application excited a good deal of attention shortly after it was made public — in 
 this country, about 1840, and large expectations were formed as to the revolution it was destined to 
 cause in the manufacture of iron. But, either from some intrinsic difficulties, not at first apparent, or 
 from bad management, its subsequent development has not been so extensive. 
 
 Faber’s method, if confined to gases existing at or very near the trundle-head, would be perfectly 
 unexceptionable ; when, however, they are drawn too low down from the body of the materials, there 
 is reason to apprehend that the train of the furnace will be disadvantageously embarrassed. At least, 
 such seems to be the conclusion of those most practically conversant with smelting. This train is, as 
 we know, very easily, and sometimes unaccountably, deranged ; and there are few processes in the 
 arts, where large masses are in action at once, so liable to the influence of apparently slight causes, 
 and so much under the domain of what may be called the working. Before leaving the subject ol 
 smelting, then, some particulars must be mentioned in regard to the working of the furnace. 
 
 For working a single coke-furnace of the first class, the following statement may be taken of the 
 hands usually found necessary, with their respective occupations : viz., two keepers, who take turn and 
 turn about, every twelve hours, in the tymp-arch and below ; two fillers, who are engaged in a similar 
 manner about the trundle-head and top-house above, each with a boy to help ; two cinder-fillers, in turn, 
 to clear away cinder below ; one cinder-hauler ; one engineer and helper at the blast-engine ; one weigher 
 of pigs : all these (together, 9 men and 3 boys) are engaged, day and night, in and about the stack. 
 Besides these, for ore-roasting are required one man and two boys ; for coking, two men and eight, 
 bovs ; for breaking limestone, two boys ; for hauling material from the yard, (which is done on a rail- 
 track,) a man, a boy, and a horse. These 4 men and 13 boys are occupied in the yards adjacent, where, 
 and about the stack, <fcc., there is always miscellaneous work enough for four laboring hands by day. 
 This enumeration excludes the furnace-manager or founder, and underground agent ; for the first can 
 superintend the smelting, as the other can the mining, for several furnaces as well as for one. 
 
 Of course, where the furnace is smaller, as it is where charcoal is the fuel, there is not so much work 
 to be done, and, in proportion, fewer hands can do it ; where wages are high, more work might perhaps 
 be got out of each hand, or it may be satisfactory if done in a less perfect manner; but the statement 
 above is from establishments where ultimate economy has been a principal object. 
 
 None of the work that has been mentioned can advantageously be done by contract ; the fuel and 
 mine should always be prepared under the sujiervision of the furnace-manager. But a plan used in 
 all large works to a greater or less extent, is to have a tariff of wages for all the hands named ; which 
 is rated and paid per ton of metal made, according to its quality. It becomes, thus, the direct interest 
 of all hands that the furnace should yield the most possible of the best iron. 
 
 The number of hands given above may seem large, but in reality, there is a good deal of work to be 
 done, and that of a sort at intervals so hard, and under such variations of temperature, that workmen 
 about furnaces are generally short-lived. Thus, the duty of the keeper, for instance, besides moulding 
 the pig-bed, which is done at spare times, and watching the tuyeres, <fcc., which is a frequent duty, is to 
 do the heavy work sometimes required for breaking into the furnace either at the fore-hearth or at the 
 tuyeres, putting in grates, <fcc. These, which are extraordinary demands, are done under the direction 
 of the founder ; who also himself bears a hand when necessary, or calls down the filler too. The tap- 
 ping, which, when the furnace is in regular train, occurs twice in the twenty-four hours, (and, from old 
 habit, at 6 A. M. and 6 P. M.,) is generally done by the founder, except in extensive works of several 
 furnaces. 
 
 As a general principle, a furnace works best when most let alone ; care having been taken in the 
 selection and proportion of the materials and blast. But, in the best managed, accidents will not 
 unfrequently happen, the repairing of which is a serious task upon the physical energies of the workmen. 
 
 The filler, with less demand upon his reasoning faculties, has not less labor to perform ; and its proper 
 execution is one of the most important items about the furnace. Upon regular and suitable filling 
 depends more than is often supposed. Various methods' have been proposed and tried, in this respect, 
 to promote a mechanical accuracy; some very plausible, but none unexceptionable. The old, and most 
 habitual method, is to fill by hand ; the fuel, if coke, being upset from two wheelbarrows — if charcoal, 
 thrown in from baskets. Ore and flux are generally filled from sheet-iron trays. Later, a more judi- 
 cious practice has grown up of weighing all charges instead of measuring, for which the barrows, bas- 
 kets, <fcc., served. Sometimes, after being weighed, the materials are kept separate ; sometimes they 
 are mixed and charged together. This last, if well done, is undoubtedly the best. 
 
 When furnaces are built on a plane, with the yards around their base, the labor of the filler is some- 
 times much increased. With such furnaces there is often an inclined plane, along which a separate 
 engine generally winds up the trucks containing the charges ; or the blast-engine is geered for the same 
 purpose. In both cases, the different diameters of the fore and hind wheels keep the platform of the 
 truck horizontal. The filler takes passage along with his freight. Sometimes a vertically elevating 
 machinery is employed ; as the equilibratro water system of Staffordshire, where the counterpoise to 
 the charges ascending is a bucket filled, pro hac vice, with water, and discharging itself when it strikes 
 the ground. Empty, it is overbalanced by the platform for the baskets ; which, upon being cast off, 
 again descend to be filled, &c. 
 
 The number of charges per turn, of twelve hours, varies with the work that the furnace is doing from 
 20 to 48. As soon as made, each one is scored by the filler upon a board for the inspection of the 
 founder ; who thus sees at a glance what the furnace is bearing, and can direct accordingly. 
 
 The business of keeping the tymp-arch clear of cinder is, .with a first-class coke-furnace, no little oc- 
 cupation of itself. It is dragged off with long hooks, in large masses, to a suitable place in the moulding- 
 nouse ; where, if necessary, it is quenched and broken up in order to being loaded on a cart. Mixed 
 with broken stone, or even by itself, it forms one of the best materials known for road-metal. 
 
106 
 
 IRON. 
 
 The breaking off, weighing, and piling the pigs, sows, and runners, (as the different moulds in a pig 
 bed are called,) is another task in a large furnace. The number of pieces in a day will amount to about 
 £00, from 50 to 60 lbs. each. 
 
 The moulding, &c., of castings, which are not unfrequently made at the blast-furnace, belong more 
 properly to the next division of the subject, that of founding. 
 
 II. Founding , or casting crude iron in fusion into hollow moulds, no doubt followed, historically the 
 working of the metal in a more or less malleable state ; but, in the chronological sequence of processes, 
 it comes, as here, directly after the production of the crude iron itself. Indeed, for some objects, this 
 crude iron answers very well itself, without a second fusion ; but, in the general business of casting, 
 particular qualities of metal are required for particular objects, and certain characters are attainable 
 only by a mixture of different sorts of metal at once. It is obvious that these conditions are not attained 
 with a single or even several blast-furnaces. Further, in the casting, care has to be taken to have the 
 metal entering the moulds of a suitable temperature ; this would be more difficult in metal that is run 
 out , as generally it has to be, from blast-furnaces, than in that which is first received in a ladle, where 
 it is kept till of a supposed suitable temperature to be poured. Finally, it is often neceesary (as for 
 blowing-cylinders, &c.) to have a greater weight of metal than the hearth of even a large blast-furnace 
 contains ; resort must be had, in such case, to several separate furnaces, whose united contents may 
 suffice. But wherever rough castings, as they may oe termed, viz., tram-rails, railroad chairs, hollow- 
 ware, &c., are to be made in quantity, where the shape and dimensions of the moulds will allow uniform 
 cooling, and where the highest quality of metal need not be possessed, or at least such quality as is 
 attained by mixtures, it is the best economy to put the blast-furnace upon a proper train for the purpose, 
 and to cast at once, either by run-outs or pourings, from it. 
 
 There are general principles about moulding and casting which govern in all metals and alloys. 
 These should have come under a special article, Founding ; but, in default of that, will be found under 
 Metallurgy. All that will be given here, will be such principles, precautions, and practice, as belong 
 particularly to iron-founding. 
 
 In general, the metal suitable for castings is gray crude iron ; for certain cases where the surface is of 
 no great consequence, (i. e., the perfection of the casting,) and where the resistance is to a crushing 
 force, white iron may be used. 'The effect of a remelting is to consume the carbon, both free and com- 
 bined, to a greater or less degree ; and the aim is to produce a metal which shall contain the least 
 quantity of free carbon, and at the same time retain the octahedral crystalline structure that character- 
 izes gray iron. This structure, other things being the same, appears to be chiefly affected by the ca- 
 pacity of the metal for heat, its radiation, and the circumstances under which it cools. 
 
 Iron may be melted either, 1st, in crucibles or pots ; 2d, in cupolas; or, 3d, in reverberatory furnaces. 
 The first are made of sand, as the Hessian crucibles, or of black-lead, like the blue-pots of commerce. 
 They are of various size ; but the largest will not hold more than 35 lbs., beyond which they become 
 unmanageable. They are set upon some refractory stand or shelf, in a suitable oven. Not in contact 
 with air directly, the loss in remelting ought not to be more than five per cent. In fact, however, it is 
 much greater ; and experience seems to dictate, as the best economy, rather to bum away a portion of 
 the iron than to use a vitrifiable flux. Where the temperature is not at command, it is better to use a 
 flux, both as an economy of fuel and of metal. It is obvious that the application of this method is 
 limited to small articles. The advantage of it, in such cases, is the beauty and finish of surface it affords. 
 
 In the second method, that of cupolas, the metal is in contact with air, fuel, and flux. There is, 
 therefore, both a greater loss and an inferior result. This loss may be rated, on the average, at 8 per 
 cent. The introduction of cupolas followed upon the use of the pots ; and they have grown from the 
 little portable furnaces of France (about 
 the year 1700) — say two feet in height, 
 in parts — into miniature blast-furnaces, 
 
 10 and even 15 feet in height. To show 
 that this is no limit in economy, although 
 it is, perhaps, in the labor, may be ad- 
 duced a case in Prussia, some years ago, 
 where a blast-furnace 34 feet high, which 
 worked in hollow-ware, had become so 
 encumbered with scraps, that it became 
 a serious matter to disembarrass the es- 
 tablishment. For this, they built inside 
 of the stack somewhat in section like a 
 fluss-ofen before described, narrowing 
 it to 22 inches at the trundle-head ; 4 ^ 
 feet at the boshe-s, which received a 
 slope of 45° ; with a hearth 15 inches 
 in diameter at top, and twelve inches 
 below. AVith this was remelted, in 21 
 weeks, very nearly 240 tons of metal ; 
 the fuel (charcoal) was 34 per cent, of 
 the yield, and the loss of metal was 8 
 per cent. 
 
 The little furnaces of 1J to 2J feet 
 are, except for special purposes, very 
 much out of use. Fig. 2377 shows, however, a small swinging furnace in section, like those still eni 
 ployed in Sweden. The dark parallel lines show the barrel-shaped casing of stout sheet-iron, or boiler- 
 plate, inside of which the fire-brick are laid. The whole concern rests, and can be made to swing, on its 
 
IRON. 
 
 107 
 
 journals, i i, which work in an appropriate gallows-frame, seen below At l m are staples, in which iron 
 levers can be thrust to tilt the furnace over and pour through the tap-hole h, which is furnished with 
 projections on which a clay lip, or runner, can bn moulded. This tilting is still further helped by placing 
 the centre of motion an inch or two below the centre of gravity when the hearth is full. The ash-hole, 
 for cleaning out, is shown at p , and 1 1 represent the two tuyhres used. Over the throat is fixed a hood, 
 or mantle, connected with a chimney-flue. These cupolas are about 8 feet high ; the tuyere, from 14 to 
 1 6 inches above the hearth, which, as shown, is made of fire-clay, well packed and beaten on the iron 
 bottom. The diameter at the bottom is 18 inches ; across at the tuyeres, 30 inches ; at the throat, about 
 2 feet : on the average containing about 1000 lbs. of metal. 
 
 Figs. 2378 and 2379 show a section and ground-plan of a neat and convenient form of cupola. The 
 exterior is of cast-iron plates, with flanges that bolt together ; the m-walls of fire-brick ; the space bo 
 tween the casing and in-walls filled with coke, dust, or ashes. Tho bottom is an annular plate, upon 
 
 2378. 
 
 foundation of masonry, which should be well drained, as shown at d. The hearth itself is made of fire- 
 clay, sloping outwards to the lip in order to make a clean run-out. The height of such a cupola is from 
 8 to 10 feet; the tymp, as it may be called, (i. e., the tap,) is 12 by 16 inches high. (This is made 
 large purposely, in order to get at the hearth for cleaning it, and, when the cupola is working is stopped 
 up.) The tuyere can be varied from 16 to 20 inches above the hearth. ’ 
 
 The hearth in this figure is represented as very large— the object being to save metal and repairs, 
 rather than fuel. In general, a narrow hearth saves fuel ; but it is at the expense of metals oxidated 
 and in-walls worn. The comparison for ultimate economy must be made in each case ; and the result 
 will differ according to the locality. Where fuel is dear, the hearth may be narrowed to advantage. 
 
 The internal shape of cupolas does not appear to have been much studied, if one may jud<re° from 
 their variety. These rules, however, may be safely taken ; that, with charcoal, the height should be 
 greater than with coke, on account of the greater friability of the material, and the greater tendency 
 of the crude iron to descend too soon. A cupola for coke ought not to be less than 6 feet in any case • 
 nor, with charcoal, less than 9 feet. The English cupolas for coke are ordinarily 8 feet hio-h, and about 
 3 feet wide, holding between 3 and 4 tons. The best form for economy is that of a small blast-fur- 
 nace, proportioned as for refractory materials. 
 
 According to the size, the quantity of blast, under a mean pressure of 14 lbs., will be from 250 to 
 550 cubic feet per minute. The fuel consumed under a good train will be, with the best coke, about 30 
 per cent. ; with coke of inferior quality, 50 per cent. ; and with charcoal, 75 per cent, of the yield, 
 which, in the best cupolas, is about one ton per hour. If the pigs are not very clean, no flux need be 
 used ; if scraps are to be worked up, limestone (chalk is preferred in England) or oyster-shells must be 
 added in small quantities. If the average loss of metal, in remelting, is more than 8 per cent., it must 
 generally be attributed to some error in the building, or in the management. 
 
 When a cupola is connected with a high-furnace, the blast is generally taken off from the blowing- 
 engine. Otherwise, the fan-blast, already described, is the most convenient. It is also well, in cupolas 
 for large work, to have three or four tuyere-holes at different elevations, to which the nozzles can be 
 successively applied as the hearth fills. 
 
 The third method of remelting is by reverberatory furnaces, where the metal, not in contact with fuel, 
 is fused by the heat of the flame that, from the peculiar shape of the roof, is reflected and reverberated 
 down upon the bottom, or sole. With a reverberatory furnace proper, there is no blast or impulsion of 
 air— it is all aspiration — and the necessary draught is created by the height of the chimney. Figs. 2380 
 and 2381 show a vertical and horizontal section of one of the best forms of reverberatory furnaces ; in 
 which a indicates the ash-pit, with the grate-bars over it ; cc the cliarging-door for fuel ; b b the bridge 
 dividing the fuel from the metal to be melted ; dd the charging-door for the metal ; (both c and d are 
 balance-doors, that slide vertically, shut tightly, and, wlien the fire is to be most intensely urged, must 
 be luted ;) h h the hearth, or sole, on the upper part of which, near the bridge, the metal is charged, 
 and along whose inclined surface it, when melted, runs ; i i the dam, whose function is as well to nar- 
 row the chimney-throat, as to retain the fused metal ; k the chimney ; and 1 1 the tap, where the metal 
 
108 
 
 IRON. 
 
 is run out through the dam, and which is stopped with clay till needed. This tap is sometimes placed 
 m the side, but disadvantageous^. The inner parts of this furnace and chimney are built with fire- 
 brick ; the sole, which needs frequent repair, laid of fire-clay, resting either on massive or arched 
 
 
 
 masonry, or on castings ; the external parts of common brick, well tied with iron bolts and plates ; the 
 chimney, which, in the figure, is represented fragmentary, should be, at a minimum, 40 feet in height, 
 and is terminated with a damper, as shown in Fig. 2382. The flue in this figure appears cylindrical 
 which is the best for the draught, al- 
 though it is generally made square. 2382. 
 
 In no case ought its section to be less 
 than a square foot. The damper, 
 which is worked with a light chain or 
 wire, a9 shown, should always be 
 provided with a register-scale below, 
 calculated for different degrees of 
 opening and draught. 
 
 The dimensions of such furnaces 
 are at discretion : some hold hardly 
 a ton, others three and four tons. 
 
 But the proportions of the principal 
 parts — viz., the fire-grate, the heard), 
 and the chimney — must be subject to 
 the laws of Pneumatics and Heat, and are, therefore, not arbitrary. The following rules, which are far 
 from having the generality and exactitude that would flow from a fully explored theory, may be taken 
 as in accordance with the best practice : 
 
 1. The higher the chimney, the better and more manageable the draught, other things being equal 
 If the section of the chimney be too narrow, the draught will be choked ; if too wide, it will be weak- 
 ened. When one stack is built for several furnaces, each one, then, should have its separate flue. 
 
 2. The sections, respectively, of the narrowest part of the throat (about i, Fig. 2380) and the widest 
 part of the shaft, (near k,) may vary between the limits of 2|- : 1 and 3 : 1. This variation can be 
 made from time to time, according to the nature of the fuel and of the metal to be melted, by packing 
 more or less sand upon the dam. 
 
 3. With a given capacity of hearth and given fuel, the areas of the throat and fire-grate must be in 
 constant proportion. This is easily ascertained by observing how the furnace works. If fusion takes 
 place the soonest near the bridge , it may certainly be concluded that the area of the throat is too small ; 
 if fusion occurs sooner near the dam, the throat is too large. The numerical ratio will vary according 
 to the strength of the coal and the length of the hearth : it may be assumed, as a mean, that the ag- 
 gregate of the open spaces between the bars should be 34 times the area of the throat. 
 
 4. The absolute capacity of the furnace is, of course, determined in advance by the work it is in- 
 tended to do. Its relative capacity should be such as that it goes on continually contracting itself the 
 further from the grate ; so that there should be an equal degree and quantity of heat in every part. 
 
 5. The length and width of the hearth, two of the elements of the capacity, should vary according 
 to the fuel. On an average, the length may be twice the width. With coal that gives much flame, it 
 may be 24 times the width ; with a dry coal, and especially anthracite, it should rot be more than 1 4 
 times the width. 
 
 6. The area of the hearth should not be more than 34 times the area of the grate, bars and all. 
 
 7. The height and width of the hearth should be such as that a vertical section through its widest 
 part, near the bridge, should be f the horizontal section of the grate. 
 
 8. The slope of the hearth need not be more than 4 inch to the foot, which allows the iron to run out 
 freely. If the inclination be great, there is no chance for yet solid fragments to be soaked (as it were) 
 in already melted metal, and thus be facilitated in their fusion ; while there is also a greater liability to 
 decarbonization, and consequent formation of carcase. 
 
 9. The height of the bridge above the hearth depends upon the fusibility of the iron to be melted. 
 If easily fusible, it may be from 8 to 10 inches in height ; if refractory, not more than 4 or 5 inches. 
 
 10. The section of the grate has been given already in terms of the other parts. The space betweer 
 
IRON. 
 
 109 
 
 the bars may vary from 05 to 0T5 inch, according to the size of coal. The depth of ash-pit. may he 
 lessened in proportion to the inflammability of the coal ; but it should always be considerable enough tc 
 avoid having the air heated by transmission over fallen cinders and ashes. 
 
 Theoretically, it would hardly appear that a large reverberatory furnace should give a less intense 
 heat than a small one ; practically, however, this is found to be the case, which may arise from this — 
 that in proportioning the size of chimney, beyond a certain limit there occurs the phenomenon of as- 
 cending and descending currents. 
 
 The foregoing rules apply to furnaces worked with coal, which is by far the most economical fuel for 
 these arrangements. "When wood is used, which contains less carbon and more oxygen, there has to be 
 a material alteration in the proportions. In a successful example, the area of the grate was two-thirds 
 that of the hearth, four times the widest section beyond the bridge, and ten times that of the throat. 
 
 Every time iron is fused it becomes more refractory, especially after reverberatory fusion. Metal of 
 the first and second fusion should not, therefore, be mixed together; and, as far as possible, only those 
 of the same or nearly equal fusibility. So also the fragments ought to be of the same size. If any 
 difference is allowed, then the larger pieces ought to be charged nearest the bridge. 
 
 In charging, it is well to get the heat of the furnace well up first, and afterwards the aim should be 
 to raise it to the full height as quickly as possible. A low temperature is only at the expense of fuel 
 and metal. After the iron is liquefied, every care must be taken to keep out cold air; the fuel must 
 be charged quickly, frequently, and in quantities that will just maintain a continued and active com- 
 bustion. If too much is thrown on at once, the temperature fluctuates ; if too little, it falls. From coe- 
 half to three-quarters of a bushel of coal, every ten minutes, will keep a grate of average size (say nine 
 square feet) sufficiently supplied. The best test is the flame at the top of the chimney : if it does not 
 appear there, even with a chimney of sixty feet, there is a waste of metal ; if, on the contrary, it shoots 
 out much above, there is a waste of fuel. 
 
 The average consumption of coal is about 60 per cent, of the yield ; the waste of metal about 1 per 
 cent., with a good train. The average effect, under equal volumes of coal to wood, is very nearly seven 
 \o one. Upon the experience in Russia, it takes, by weight, of seasoned wood, 150 per cent, upon 
 the yield. 
 
 The time taken to melt down a charge is very variable, according to the fusibility of the metal, the 
 strength of the coal, the proportions of the furnace, and the management. The average power of fusion 
 may be rated as equivalent to one ton per hour, and the furnace can be tapped, according to circum- 
 stances, (size, <fec.,) every two to four hours. 
 
 If the scope and practical appliance of these three methods of founding be compared, it may be 
 said that, 
 
 1. The employment of crucibles, very costly in materials, though not in construction, is limited to 
 small objects, whose price bears no comparison to the weight of metal out of which they are made. 
 
 2. Cupolas, which are rather the most expensive in construction and maintenance, are yet worked 
 more regularly with a less proportionate expense for wages, and are the most universally applicable 
 for all objects of ordinary demand ; and, 
 
 3. Reverberatory furnaces are especially required for castings of the heaviest sort, where the max- 
 imum resistance of the metal is demanded. 
 
 In all, the same general principles apply in the management of the metal before and after fusion. 
 Thus, the mixture or charge of different kinds of crude iron is a point of great importance, both as 
 regards fusibility, and the properties of the cast-iron run out. Castings will hardly ever be made from 
 one sort of pig only ; at least two, and often six or eight sorts are charged together. This is a matter 
 dependent upon the practical experience and judgment of the founder, for which no written rules serve. 
 
 So also the pouring of the iron, or conveying the melted metal to the flasks, is independent of the 
 kind of furnace in which it may have been fused, and is determined by the quantity required to be 
 poured at once, and the character of the casting, whether it is to be open, or in close moulds. Very 
 large objects, with plane surfaces, (such as girders, plates, <&e.,) are generally cast open in sand-moula^ 
 and the metal runs through a gutter (frequently itself of iron) lined with sand, after the same fashion 
 with the sow and pig casts from the high-furnace. But when the surfaces are curved or re-entering, 
 (as cylinders, &c.,) it is best to pour from ladles. These ladles vary in size, and, of course, in manage- 
 ment, according to their purpose. A hand-ladle, which is wielded by one man, will contain from 50 to 
 60 pounds ; a double hand-ladle, or shank, managed by three or four men, carries from 200 to 400 
 pounds ; ladles holding four or five tons travel in a crane. The handles or pivots of all these are placed 
 a little above the centre of gravity of the ladle when charged, so that they may be easily tilted. With 
 the smaller ladles, accidents, either to the workmen or the contents, are rare ; the largest are now so 
 improved with tangent-screws, worm-wheels, and skimmers, as to render their management even easier 
 than that of the smaller ones. 
 
 The whole business of making patterns and moulds is the same in principle for all metals, and belongs 
 to the article Moulding. Only such particulars will be summarily mentioned here in which the casting 
 of iron differs more or less from the founding of other metals. 
 
 The patterns for iron-castings, besides being made so as to draw readily from the mould, are made 
 larger than the intended casting, by an average scale of |th inch per foot. This is to allow for the 
 contraction of the metal in cooling. In strictness, every particular mixture has its own proportionate 
 contraction, and when a foundiy is running upon the same mixture and article, the pattern is dressed 
 to suit; but the proportion which is given is the one generally adopted. The pattern-maker, in getting 
 the proportion, simply uses a contraction-rule, whose divisions of feet and inches are everywhere l-96tb 
 longer than the true measurement. In this way he works directly from the measurements given, with- 
 out any trouble of calculation. In making a pattern of wood from which to cast an iron pattern, to be 
 used afterwards, a double shrinkage is to be allowed for, and a double contraction-rule, with divisiptm 
 1-4 8tli in excess everywhere, is employed. 
 
110 
 
 IRON. 
 
 Patterns for iron-castings require to be more carefully designed as to symmetry and equality of parts, 
 and distribution of material, than for any other metal, partly because of the heavier stress upon the 
 objects in use, and partly because of the peculiar behavior of the metal itself in cooling. It is easy tc 
 see that a small external stress, coming upon a material already strained by its own shrinkage, will 
 cause it to give way. Inattention to these considerations is the frequent cause of breakages in the 
 wheels for railroad cars. In planning a pattern other than for simple prismatic figures, regard should 
 always be paid as to which parts are to endure extension, and which compression. The latter may be 
 made thin, and be allowed to chill ; but the parts to resist extension should be, as far as possible, com- 
 pressed in the mould, and escape chilling. For instance, a T-shaped cast-iron joint is a bad shape at 
 best for strength, but its resistance is still less when the vertical leg is downwards. In general, patterns 
 for castings, if at all complicated, should be regarded as systems of framing; and in combining the 
 several parts, it should be remembered that the strength of the whole can never exceed the weakness 
 of the weakest part. 
 
 In taking impressions from these patterns, or moulding the object desired to be produced in metal, 
 the processes are the same for iron as for other metals, regard being had to the heavier masses required 
 of the former, and also to its different affection by heat. In this last particular, moulds for cast-iron 
 need not be so dry as for other metals. The sand employed is also coarser, and less adhesive. Sand 
 for partings in the mould is generally that which is scraped off from former castings, and which, having 
 been once exposed to a full red-heat, and mechanically triturated in the rough processes of scraping, 
 has become less sharp. The best facing-sand is charcoal and coal-dust in equal parts, ground fine, and 
 intimately mixed. For small articles of luxury, the best facing is graphite. 
 
 Cores, which are prismatic or cylindrical pieces inserted in the mould, to produce the holes and open- 
 ings in the casting, and in general intercept the flow of the metal, may be made of any material which 
 does not alter its shape or volume materially when exposed to heat. The best for iron-castings are 
 made of sand, horse-dung, and a little loam. After being shaped they are dried, and then put in a 
 crucible and burned for ten or twelve hours, in order to consume all the vegetable matter, and leave 
 them in a proper porous condition, both for their own permanence, and also the escape of air. 
 
 Castings of ordinary objects are made in iron moulds or in sand; very heavy objects, such as cyl- 
 inders, Ac., are moulded in loam. Of the use of iron moulds, the running of bullets is a familiar, but 
 perhaps the best illustration, though it is ordinarily exemplified with other metal than iron. This kind 
 of mould is applied advantageously to the casting of heavy shot and shells, (which will be treated ot 
 more particularly under the title Projectiles,) to tram-plates and chairs for railway bars, and to railway 
 wheels. In these last the outer rim only is often made of iron, and the nave and spokes cast in sand 
 upon an iron-core, the object here being chiefly to chill the tire of the wheel. Another object, plough- 
 shares, are advantageously cast in iron moulds, so also are cylinders for rolling metal, forge-hammers, 
 ore-stampers, Ac., and in general all objects which have a sufficient mass of matter to resist impact oi 
 compression, and require in use the hardest and least wearing surface. 
 
 Sand-mouldings (we do not speak here of those objects, plates, joists, Ac., which may be run open) 
 are made in flasks, which, for iron-founders’ use, are best made themselves of iron, but in other respects 
 like the wooden ones used in foundries generally. The bottom flask or drag has generally plain, flat 
 cross-ribs, to serve instead of a bottom-board ; the top flask has deep cross-ribs cutting it up into compart- 
 ments five or six inches wide and twenty to thirty inches long, with little fillets on their sides to lock 
 in the sand more effectually ; middle flasks have no such compartments at all. Of these middle flasks 
 the iron-founder makes frequent use. They constitute the three or four part flasks, which are much 
 more convenient for many objects than two-part flasks only, which might have to be of excessive depth. 
 The cottering, or fastening these parts together, is easily effected by transverse wedges in the steady- 
 pins of the flasks, and the internal mass of sand is retained firmly, or gagged, by means of lifters, or 
 T -shaped pieces of iron, with wedge-shaped tail, and set head downwards. These gaggers are placed 
 in various parts of the flask, according to the objects to be moulded, and the discretion of the founder. 
 
 The following figures, showing the pattern and mould for the top of a sliding-rest for a lathe, will 
 illustrate the application of a three-part flask. 
 
 The pattern, Fig. 2383, might be moulded in a two-part flask of sufficient depth by making the 
 parting along the dotted line a a ; and indeed there are several ways in which it might be cast, but the 
 one shown will be seen to be the most convenient. The chamfer at c might also be cast, either by 
 moulding square at first, and then filling in sand and working it to a gage, or by means of a core 
 whose print is shown in the dotted lines terminating at b ; but the most usual and the best way is to 
 
 “383. 
 
 cast it square, and plane it to the required bevel afterwards. That being the case, Fig. 2384 '’hows the 
 flasks 1, 2, 3, alter they are put together. In working them, 1 and 2 are first set, nearly fLled with 
 
IRON. 
 
 Ill 
 
 sand, and the pattern knocked in as shown, the -whole well rammed, and the parting made along a a. 
 The flask 3 is then added, tilled and rammed, levelled, covered with a board, and all three turned over, 
 so that 1 becomes the top, which is now taken off, a parting made along the line b b, and the runner- 
 stick put in to make the runner or in-gate, as shown by the dotted lines near r. To prepare for casting 
 the runner-stick is taken out, flask 1 is lifted off, and the part of the pattern (shown white) is taken out 
 from the middle flask ; the middle flask is then removed, and the shaded part of the pattern (which has 
 been fitted by pins or lugs, as shown) is taken out from flask 3 or the drag. The flasks are then united, 
 and the pouring made through r. It is manifest that the same system would be pursued with a flask 
 having a greater number of parts. 
 
 The iron-founder has, from the vast variety of works which he is called on to execute, greater occasion 
 than others to use a variety of methods of coring. The following figures will 
 illustrate some of these, and will indicate how others, more complicated still, 
 are met and accomplished. Thus, Fig. 85 shows the finished casting which is 
 desired to be produced, and Fig. 2386 tne pattern, with its core-prints for pro- 
 ducing it. The horizontal print a delivers itself, but one made like the left-hand 
 vertical one b, would tear up the sand in the attempt to remove the pattern 
 from the mould. The right-hand print d, therefore, shows the proper shape and 
 length, reaching down to the bed of the pattern. The circular opening has, in 
 the same manner, a tapering print of the same length. These prints, if we sup- 
 pose the pattern inverted, will leave a recess, as shown at d in Fig. 2387. Upon being drawn, the 
 cores are inserted as in Fig. 2388, (a section through d,) the upper part of the recess is made good with 
 sand to the general surface, and the mould is ready for casting. 
 
 238G. 
 
 2388. 
 
 2387. 
 
 2389. 
 
 By observation and practice moulders become exceedingly expert in managing their patterns, drc., 
 and often display remarkable ingenuity in the shifts and contrivances to which they resort for eking out 
 or stopping off patterns, or for moulding additional parts for which there is no pattern. Indeed, as one 
 of the heavy items of expense in a foundry is for a stock of patterns, it is not unusual, for avoiding this, 
 to see many common articles of simple form, (grates, parts of stove-plates, etc.,) which are made upon 
 written orders, built up with core-prints or slips of wood, and moulded almost entirely by hand. 
 Wherever accuracy is required, however, well-made patterns are indispensable. 
 
 The objects which are moulded in sand and cast in flasks are too numerous to be mentioned. They 
 comprehend nearly all the articles of cast-iron in ordinary or domestic use. Before leaving this branch, 
 another illustration of flask-casting of the last-mentioned class of articles may be 
 of interest to some readers, viz., the manufacture of iron pots. Fig. 2389 will 
 give an idea of the implements in this process. The pattern for the pot (which 
 is of metal, for wood could not be turned down well to the thinness of these 
 vessels) exists in two hemispheres, which fit and are fastened together in the 
 oblique dotted curve shown in the figure. The moulder takes these and places 
 them together, mouth downwards, upon a board which has a bevel-rim just fit- 
 ting the mouth of the pot. On the same board, he places symmetrically over 
 the pattern the flask a , which is in two pieces, as shown. Sand is rammed down 
 round the pattern till the flask is full, when a parting is made even with its top, 
 
 and flask b is placed on and fastened. This is filled in like manner, prints for ._ 
 
 the feet and a runner-stick having been put in at the proper levels. The top of ViiiiijVyj 
 b is levelled off, a board placed on it, and the whole concern inverted. The 
 board that originally served as the drag, and upon which a and b have been built, is removed, the 
 interior of the pot is seen, and the flask c is set around its mouth upon a. The pot is then filled with 
 sand and rammed to the edge of c, when it is all strickled, (i. e., levelled off,) a drag-board placed on it. 
 and the whole reverted to its former position, as seen in the cut. In drawing the pattern, b comes off 
 first, out of which the core-prints are also taken ; a takes apart and leaves the pattern exposed, which 
 comes out in halves. The convex and concave moulds are then dressed with tools and facing-sand, the 
 flasks replaced, the runner-stick taken out, and the whole is ready for casting. In spite of the apparent 
 complexity of all this, it is by no means among the costlier or more difficult works of the foundry. 
 
 Articles that are heavy or large have to be moulded in loam, as it is termed ; and as such things are 
 generally required to be cast vertically, while the quantity of metal is too great to be ladled, it is more 
 convenient to dig a pit for the mould to which the metal may be led by gutters, than to raise the fur- 
 nace foundations high enough to have all the work above ground. Indeed, as works have sometimes to 
 be executed fifteen and even twenty feet high, this last arrangement would be well nigh absurd. So 
 far as resistance is concerned, pit-moulding is advantageous; and if due provision be made for the es- 
 rape of elastic gases, it is not more objectionable on the score of danger than large flasks above ground 
 The great merit of this method is, however, in dispensing with a solid pattern, which, for such cylinders, 
 for instance, as are used in Cornish engines, of eight feet diameter and fifteen feet stroke, would be an 
 
112 
 
 IRON. 
 
 enormous expense. The following figures will serve to explain the general process of loam-moulding. 
 Fig. 2390 shows the first stage of the mould for a steam or blast cylinder. The lowest lines represent 
 the bed of the loam-plate, upon which the inner wall is built. This inner wall, for small works, such as 
 pipes, is called the core , for large cylinders it is termed the nowel. The loam-plate is of iron, cast rough, 
 and with projecting ears for lifting it. Sometimes these plates are raised from the ground, to allow of 
 a fire for drying the loam to be made up beneath ; or if the work be not too large, it is set upon a 
 wheeled truck, by which it may be rolled into the loam-stove. Upon this truck, or on the loam-plate, 
 or in any convenient and steady manner, a spindle a is fixed, which carries the templet b b , whose dis- 
 tance from the centre is adjusted exactly to the internal radius of the intended cylinder. An inner wall 
 of brick-work is then built, whose face is plastered with soft loam, which loam is shaped and turned by 
 the motion of the templet. When smooth it is thoroughly dried, and then brushed over with black- 
 wash of charcoal and coal-dust, to be dried again, and serve as a parting to prevent the adherence of 
 fresh loam. This finishes the mould for the inside of the cylinder. 
 
 The templet b b is then dismounted, and another cc, Fig. 2391, cut in profile to the external form of 
 the cylinder, with flanges, and bosses, <fcc., is attached to the spindle at a distance from the centre ex- 
 actly corresponding to the radius of the cylinder , plus its intended thickness. Fresh loam is then thrown 
 on the nowel-mould, in order to form the thickness, which is shaped on the outside by the revolutions of 
 the templet, carefully smoothed, dried, and black-washed as the other. 
 
 When this is finished, a loam-plate or ring is laid down to carry the outer case or cope, as shown in 
 Fig. 2392. This cope is built up of brick and loam, with an inner facing of loam worked carefully to 
 the turned thickness ; it is then thoroughly dried, and lifted off carefully from the nowel. This is done 
 by means of a crane. The thickness comes off with the cope, generally broken, but it has now answered 
 its purpose. Any accidental damage to either of the moulds is repaired, the faces are black-washed 
 and dried again, and the mould is ready to be put together, the position of the cope having been deter- 
 mined at first either by studs, or by marks upon the nowel-plate. 
 
 Ports at the ends of the cylinder (or short flanged tubes for attaching the steam or blast pipes) are 
 made by working the patterns into the cope ; the cores are supported either by grains (which are little 
 plates of sheet-iron staid by wire, and as wide as the thickness of the metal at the port) or by sand- 
 bearings, the holes left by which are afterwards plugged up. From the precariousness of the union of 
 the melted metal with that of the wire and sheets, the use of grains is, when possible, to be avoided. 
 Other passages for steam or air, either in the side or around the cylinder, can be worked in a similar 
 manner upon the thickness, and be covered in by the cope. 
 
 When all is ready the mould is put together in the pit, the two plates bolted together, and the ex- 
 ternal space in the pit rammed hard, to resist the outward pressure of the melted metal. In very large 
 works there are iron rings, larger than the cope, piled one on another to hold the sand ; these rings are 
 steadied by numerous stays going to the sides of the pit, which is sometimes itself walled up with brick, 
 or even cased with iron. In such works the core too has to be strengthened by iron stays laid in diam- 
 eters, and entering the brick-work of the nowel. 
 
 The metal, in pouring, is led in various ways to the mould, according to circumstances, from the sow 
 or main runner. Sometimes there is a circular trough round the top of the mould, and the feeding is 
 through holes in the loam-cake ; sometimes the runners are sunk, and enter the mould at about one- 
 third of the height from the bottom and tangent to the circumference. This is supposed to be a good 
 way to keep the metal in circulation, and clear of the scorise or sullage. Sometimes, to supply hydro- 
 static pressure for condensation, or shrinkage in cooling, iron rings are piled up to inclose a lofty runner. 
 In the largest works several such reservoirs or feeds are made in addition to the runners, purposely to 
 provide for shrinkage. Sometimes a piston has been applied in the runners, when they are not numer- 
 ous ; and a still better-intended process has been proposed — that of exhausting the air from the mould, 
 and supplying the feed from below. 
 
 Both of these methods — which have never come into general use — aim at accomplishing perfectly 
 what the founders ordinarily obviate by other contrivances, viz., the expulsion of the air from the mould. 
 If the air or vapor in small quantities gets entangled in the metal, it produces, of course, a bad casting, 
 leaving cavities in the mass such as we very often see. If large quantities, especially of steam, are 
 caught, the consequence is a greater or less explosion, sometimes attended with very disastrous conse- 
 quences. The Thorncliffe accident in 1820 is still remembered in the annals of founding as one of the 
 
IRON. 
 
 113 
 
 saddest of such catastrophes. Upwards of 100 persons were in the cast-house at the time, to witness 
 tire pouring of a tilt-shaft of about live tons in a vertical mould. The cast was nearly finished when 
 the explosion took place, and some four tons of melted iron shot out as from a petard, killing and 
 wounding terribly about one-fourth of those present. There happened to be a thunder-storm at the 
 time, and as no one knew of any mistake committed in any of the arrangements, the accident was at- 
 tributed to that indefinite agent, electricity. It more likely arose from a sudden and explosive combi- 
 nation of carburetted hydrogen, a gas which is always formed in the moulds. The workmen are very 
 well aware of this, and in casting, for example, the thick cylinders for a hydrostatic press, which are set 
 mouth downwards generally, the air-tube or tubes which are made to come up from the core underneath 
 to the surface are ignited for greater safety, and bum like perfect gas-torclies. In small works this is 
 not so manifest, and in these, by making openings similar to and corresponding with the runners, the 
 metal flows through the mould, and drives out the greater quantity of the air and gas before it. In 
 larger works the air-chamber is generally provided below, underneath the nowel-plate, by laying there 
 i mass of hay-bands, with which air-tubes, leading to the surface, immediately communicate. But the 
 i-se of this combustible matter cannot be recommended on the score of security. 
 
 The temperature proper for pouring is slightly different for every mixture ; it can be judged of only 
 by experience : at least it cannot be defined by any written rules of universal application. The rate of 
 pouring, too, is in the same category. In general, bad castings (i. e., blown and spongy) are apt to be 
 made by quick pouring of hot metal, and imperfect ones by slow pouring. 
 
 The necessity of providing sufficient resistance to all sides of the mould during pouring has been 
 already spoken of. After pouring, however, the condition becomes inverted, for the metal is then 
 shrinking into itself. The pressure from without is generally nothing ; but that from within must be 
 removed, that the cylinder be not strained, or scored. So, in two or three hours, according to the size of 
 the work, the iron stays within the core are knocked away, and the workmen go down to break away 
 the brick-work. The excessive heat renders this the most dreadful of their duties. 
 
 Loam-casting, suitably modified, is applied to all large works with curved surfaces, such as cylinders 
 of all sorts, large pans, guns, pipes for water, gas, &c., dx. Guns have been cast with a core, like cyl- 
 inders, but their imperfections are such as to make it more advantageous, in spite of the waste of metal, 
 to run them solid and bore them out afterwards. The cores for pipes are usually made upon an iron 
 tube pierced with holes, wound round with hay-bands, and revolved, while the loam is being applied, 
 by a winch at the end, upon two iron trestles. A scraper, fixed parallel to the axis, turns off the loam, 
 and brings the core to its true cylindric shape. This arrangement, which is susceptible of more accu- 
 racy, is the founder's lathe. These cores are dried and blaekwashed ; the thickness is laid on in loam, 
 and also dried and blaekwashed ; and the object is then moulded in sand in an iron box parting in 
 half. The core is then taken out, the thickness removed, and the core replaced, and held in place, if 
 necessary, with grains. In establishments where pipes are cast in large quantities, it is usual to mould 
 from wooden patterns in halves. 
 
 Within a short period, a method has been tried of casting pipes inside of an iron pattern, whicli is laid 
 with a slight slope, and caused to revolve while the metal is fed. Its revolutions inspire a centrifugal 
 tendency to the melted metal, which is restrained and shaped, as it cools, by the pattern. The precari- 
 ousness of result, however, or some other cause, appears to have restricted the economical use of this 
 method. 
 
 The scope of the iron-founder’s art is exceedingly comprehensive, both as to the forms he produces, 
 and the weight of metal he has to deal with. Thus, castings are sometimes required of 20 and even 
 30 tons in one piece, requiring the conjoint operation of three or four furnaces tapped at one time. On 
 the other hand, the beautiful Berlin ornaments are cast in pieces of a few grains weight. The art of 
 casting these ornaments was first developed in Prussia, and is supposed to depend, in some degree, 
 upon the quality of the iron and of the sand employed. The latter, as well as the ores (bog-ores) out 
 of which the former is reduced, is not only fossiliferous, but appears to be constituted entirely of the 
 remains of atiimalculas. But there are examples of successful castings of the smallest size with mate- 
 rials where this infusorial influence could not be suspected of operating. 
 
 The following figures exhibit one of these Berlin chains entirely of castings (many of those on sale 
 will be found to have been connected with iron wire) : its length is 4 feet 10 inches, and its whole 
 weight 130 grains; a large and small link together weigh a little over 8 grains. Fig. 2393 shows the 
 
 2393. 2394. 
 
 chain itself; Fig. 2394 is intended to explain the way it was worked. The large links a a (Fig. 2393) 
 were first cast separately. Then a pattern of the chain with core-prints b (Fig. 2394) was moulded. 
 The links a, smoked to prevent adhesion of the metal, were laid in the mould, and then the sand-cores, b. 
 The actual mould was about 8 inches long, and a separate runner was made to every one of the small 
 links c c. Such things are even greater wonders of art than the larger works. 
 
 When castings are set and cooled, the next thing is to remove them from the moulds ; the runners 
 are snapped off, and all the loose sand scraped from the casting, and the seams of partings smoothed 
 For common castings, very rough implements serve ; for the finer kinds more appropriate tools are 
 required. To these, the skin left from a sand-mould is very destructive ; and therefore, if they are 
 intended to be wrought, they are generally first pickled with dilute sulphuric acid — by immersion it 
 Vol. II. — 8 
 
114 
 
 IRQ*. 
 
 they are small, and aspersion if large. The acid attacks the metal underneath ; and the crust that is 
 left after a day or two is easily removed. 
 
 The skin of castings from sand-moulds is always harder than from loam. This is not so much front 
 the siliceous matter taken up in the surface, as from the effect of a different conduction of heat, and a 
 change of crystallization at and near the surface, which is known as chilling. These chilled castings 
 have been already mentioned : it only remains to speak of the malleable iron castings which are pro- 
 duced at a few establishments. 
 
 The malleability, which is in some respects the reverse of chilling, in general follows the abstraction 
 of carbon, and is proportionate to it ; but the metal so produced lias none of the fibre which is caused 
 by forging and laminating. Like chilling, the change is external, and penetrates but a small way ; the 
 methods, therefore, are applicable only to light and thin articles. There are many such (brads, bridle- 
 nits, coach-makers’ fastenings and furniture, locks, snuffers, stirrup-irons, (fee., and various vessels in 
 domestic use) which can be cast more cheaply and conveniently than forged : to all these the method 
 applies. 
 
 It reposes both upon the character of the crude iron and upon processes subsequent to casting. Gray 
 crude iron produced from refractory ores, which never can be chilled, is the suitable quality ; and arti- 
 cles cast from this, which are at first brittle, are enclosed in iron boxes, in contact with powdered oxides 
 of iron, (either mineral, as red hematite, or artificial, as forge-cinder,) with lime, or with any absorbents 
 of carbon. The cases, well closed and luted, are placed in an oven, and left there, at a high tempera- 
 ture, for a period varying from three days to a week. The temperature is then allowed to subside, 
 and the matters to cool gradually in the ovens. When pieces of these castings are fractured, the alter- 
 ation of structure is very apparent. 
 
 III. Refining, Forging, <fcc., of Malleable Iron. — The mention of malleable iron castings leads 
 naturally to the account of those processes by which a malleability is imparted, higher both in kind and 
 degree. These processes apply, 1st, to the production of iron which can be wrought directly from suit- 
 able ores ; as well as, 2d, to the refining and working of crude iron which has been otherwise produced. 
 The fagoting of scrap-iron is not sufficiently distinctive, either chemically or mechanically, to constitute 
 a third class of processes. 
 
 1. Of malleable iron directly from ores. — This product undoubtedly preceded any other manufacture 
 of iron. All the workings of antiquity were of this sort, there is reason to believe ; and what has been 
 already said in this article serves to show the gradual advance of the modern epoch of crude iron. The 
 improvement in this epoch has been the utilization of many ores which, under the old process, were 
 unavailable. Only rich and fusible mines — magnetic oxides, and some of the sparry carbonates and 
 red hematites, and the like — admit of this treatment. This restriction will be justified in considering 
 the general theoretical aim of the process, which, in so far different from that of the high-furnace, em- 
 1 'races a double task, and recurring decompositions and recompositions. In the high-furnace, our object 
 is to drive off the oxygen from the ores ; which is effected by preventing carbon in excess at a high 
 temperature, while that portion of excessive carbon that combines with the iron after reduction is gotten 
 rid of by subsequent separate treatment. But in the forge-fire, one treatment must answer both ends ; 
 carbon at the lowest temperature that will answer must be prevented to effect an imperfect reduction 
 at first, till the mass consists, in fact, of a mixture of oxides and carburets of iron ; and while this mix- 
 ture is reacting internally on itself, additional oxygen from a current of air must be afforded to assist in 
 the neutralization of the carbon. 
 
 To this aim, the character of the furnaces employed must conform ; they must be low, so that the 
 reduction may not take place too soon and fusion be checked ; they must be wide, that the melting 
 carburets may offer a large surface to the action of the air. Where exactly the fusion is maintained, 
 is not of so much moment : if above the tuyere, the furnace is properly a stuck-ofcn, which has been 
 already described ; if below the tuyfere, it is to be termed a forge-fire, of which the so-called Catalan 
 forge may be taken as the type. Whether one or the other form be used, there is in either another 
 characteristic diversity from the processes of the high-furnace, which should not be omitted. In the 
 latter, the result depends upon the chemical action of the materials ; i. e., upon the proportions of fuel 
 and mine, and the temperature which is kept up ; in the former, the chemical reactions are chiefly de- 
 pendent upon the mechanical agency of the workman, whose business it is to expose successively the 
 imperfectly reduced masses to the influence of the air. Thus the reduction and the refining are both, 
 in a measure, mechanically effected ; the formation of too much crude iron at once is cheeked by imme- 
 diate admixture of oxide, and by a judicious management of the blast ; and the result depends upon 
 the skill with which this is done, just as in the case mentioned in a preceding part, where, to produce 
 crude metal of a particular quality, doses of suitable materials are injected into the crucible of a high- 
 furnace. 
 
 So much has been already said upon the stiick-ofen, that its application need not be insisted on here, 
 further than to remark, that their product is never entirely malleable iron, and requires a fresh reheat- 
 ing and fusion of a part. This subsequent process results in the formation of part malleable iron and 
 part steel. 
 
 The furnaces used in Sweden and Norway for this purpose are also properly stiick-ofen, and the re- 
 sult similar. In some places of these countries, thev treat a roasted ore with wood in inverted cone-like 
 furnaces, from 4 to 7 feet high, and from 2J to 5 feet diameter at the top. 
 
 The old German method was also so far like that of the stiick-ofen, in requiring actual fusion ; but 
 the shape of the hearth was different, resembling the Catalan forge-fire, and the original, apparently, of 
 the modern bloomery fires of Pennsylvania. There was also another method used still in Gallicia, of 
 interstratifying the ores with the fuel which is broken fine and kept almost in a pasty state. The re- 
 duced metal filtering slowly through this paste is refined by the current of air directed downwards 
 towards the bottom of the hearth. 
 
 The methods, -<fec., which have been applied from time immemorial in the Pyrenees, and are called 
 
IRON. 
 
 115 
 
 the Catalan method, will convey a sufficient idea of all the others, which are but modifications. This ap- 
 pellation comprehends, in reality, the whole arrangement of water-blasts, tilt-hammers, &c . ; but the 
 exposition will be confined for the moment only to the chemical part of the process, or the production 
 of metal ready to be forged. The ores are generally roasted in furnaces or ovens ; but in some instances 
 a compact brown hematite has been used raw. The results, compared with roasted mine, do not appear 
 advantageous. When the ores are tolerably pure, they are usually charged in the furnace within a 
 month after roasting ; but pyritous or phosphated mines are macerated, i. e., exposed to the air, and fre 
 quently stirred and moistened with water for a twelvemonth. Before charging, they are broken up into 
 fragments, like small nuts ; red hematites are even used in powder. According to the character of the 
 ore, earthy matter, argillaceous or calcareous, is added, to serve as a flux. Throughout the Pyrenees, 
 the general machinery for the blast is the trompe that has been already described ; small forge-fires are 
 sometimes blown with leasher bellows. In this last case, to maintain a continuous blast and furnish a 
 suitable quantity, two tuyeres are required. 
 
 The following figures indicate the construction of these Catalan forges. Fig. 2895 is a ground plan 
 on a scale of 1-Soth of the actual size of the forge-fires used in the Lower Pyrenees. Such are properly 
 called Navarrese furnaces ; and while the general structure is the same for all, are intermediate in di- 
 mensions between the Spanish Catalan, which are smaller, and the Biscaj'an forges. 
 
 Fig. 2396 is a vertical section through the axis of the tuyfere ; and Fig. 2397 another section at right 
 angles to the former. In Fig. 2395, W W represents the wall separating the forge-fire from the blast 
 machinery, and in which is the embrasure for the tuyere. The hearth is usually fined with cast plates, 
 and the counter, or side opposite the tuyfere, 
 of flat bars. Sometimes the lining of these is 
 only a refractory sandstone ; but the cinder 
 slope (on the side o of the tuyfere) on which 
 the workman rests his ringers and bars, is 
 always of cast-iron. The aperture o is for 
 the discharge of cinder into the embrasure 
 beneath; the tuyere 1 is a truncated half- 
 cone of copper, with the orifice or eye circu- 
 lar, from 1 1 to 2 inches in diameter. The 
 pressure of the blast varies from i lb. to 1| 
 lb. per inch. 
 
 The fewest men to work one of these fires, 
 not counting the hammer-man, is three ; the 
 greatest number employed in the largest 
 and most active, is eight. In beginning to 
 work, the hearth has first to be heated by 
 keeping it two-thirds full of ignited charcoal 
 for 4 or 5 hours. The fuel is then thrown 
 up against the tuyhre and beaten down into 
 an inclined plane towards the counter. Upon 
 this is thrown at once from, one-half to three- 
 fourths of the charge of mine ; the hearth is 
 heaped up with charcoal ; the cinder-tap o 
 stopped with clay ; and the blast gradually 
 let on, till, in about two hours, it attains its 
 maximum. The founder, during the process, 
 frequently wets the charcoal on top to pre- 
 vent its burning too fast, and to concentrate 
 the heat ; throws on, from time to time, the 
 smaller fragments remaining of the charge, 
 near the tuybre ; feels with a crow-bar at the 
 bottom of the hearth for the cinder and met- 
 a.1, giadually brings the charge nearer the tuyfere; keeps the tuybre free ; and about every quarter 
 our alter cinder has commenced to show itself, taps and lets it off. This tapping, after the whole 
 
116 
 
 IRON. 
 
 blast is on, has to be clone more frequently: sometimes every five minutes; the other part of the work, 
 too, goes on with more activity. In three hours the whole charge is melted ; a bar is thrust through 
 the charcoal in many places to clear the metal which is thus gathered up on the bottom of the hearth, 
 and worked and pressed with ringers into a sort of ball or loop. This takes the greater part of an hour 
 when the heat is done, the charcoal is raked over against the counter ; and the loop thus cleared is 
 lifted by the bar to which it adheres, and, if necessary, with tongs, and carried to the shingling-hammef 
 to be forged. In the Catalan forges, the weight of these loops (or markets) is from 100 to 150 lbs • 
 in the Navarrese, from 180 to 250 lbs. ; in the Biscayan, from 280 to 850 lbs. ; and in some of the forges 
 among the Eastern Pyrenees, as much as 425 lbs. The tilt-hammers employed weigh from 600 to 
 100 lbs., generally of cast-iron, sometimes of wrought; the helve and fixtures mostly of wood. Besides 
 these are used smaller lift-hammers, for working smaller bars, called martinets. When the loop is 
 placed under the hammer, it is struck at first slowly to condense it and drive out the cinder ; it is then 
 forged more rapidly into the shape of a prism, 12 to 18 inches long, and 6 to 8 inches square. This is 
 cut in two by a chisel under the hammer ; the pieces carried back to the same fire as a special chafery, 
 there heated and successively forged again. When smaller bars are wanted, these pieces are again 
 cut, reheated, and forged under the martinet. 
 
 The charge of roasted mine for each heat is, with the Catalan fire, from 325 to 450 lbs. ; with the 
 Navarrese, from 550 to 650 lbs.; with the Biscayan, from 750 to 900 lbs.; and with the largest fires of 
 the Eastern Pyrenees, an average of 1260 lbs. But the economical result in metal is, as might be 
 expected, against the large charges. The smaller fires allow six and sometimes seven heats in the 24 
 hours, and give about 90 per cent, of the metal found by assay in the ore : the larger ones never more 
 than four heats in the same time, yielding about 85 per cent, of the metal. In fuel, there is less con- 
 sumption with the large charges. In the smallest fires, the fuel used is, on an average, five for one of 
 mine ; in the larger it is about three. 
 
 The fuel used is universally charcoal. Frequent experiments have been made looking to the substi 
 tution of coke, both with cold and hot blast, but hitherto, and probably of necessity, always without 
 success. 
 
 2. Of malleable iron from pig or crude iron — produced (a) with charcoal in open forge-fires, bloom 
 eries, <fec. ; (b) with coal in reverberatory or puddling furnaces ; (c) with coke or coal in a special fur- 
 nace, termed a finery, or run-out fire, and then in a puddling-furnace. The object is the same in all 
 these, viz., the decarburation of the metal, (as to driving oil' other impurities, that will be spoken of 
 specially hereafter ;) and the methods may be distinguished into two classes — first, where the metal is 
 refined in contact with carbon, as in mode a ; and, secondly, where it is only in contact with heated air 
 and inflamed gases, as in the reverberatory furnaces of modes b and c. In theory, the latter method 
 should be the best, so far as quality of metal and economy of material are concerned ; but in practice, 
 the former, though at a greater loss and expense, is the most successful in yielding a good article. 
 
 In regard to the quality of crude iron most advantageous for refining, different metallurgists have 
 expressed different opinions. As this is no place for a lengthened discussion of principles, only such 
 statements will he briefly made as seem to accord the best with experience. 
 
 Gray iron demands a higher temperature for fusion than white, becomes more liquid, and requires 
 more blast and a longer time for conversion. White iron coagulates more readily, and passes sooner to 
 the malleable state. Whether these differences arise solely or chiefly from the presence of the free 
 carbon in the former, is not the question : it is certain, however, that some kinds of gray iron cannot be 
 refined at all without having been first whitened by a special process. This is especially the case witli 
 coke iron ; and the finery of the English method is an expedient for meeting this very difficulty. The 
 best qualities for easy refining are white iron, produced in the high-furnace by heavy burden, gray pig, 
 which is loose in its texture and cavernous, and broken castings from a cupola or crucible. Next come 
 the mottled pig, the lamellar and loosely crystallized white iron, and close-grained gray coke iron 
 Last of all to be employed, are the compact crystallized gray pigs, especially those made with coke oi 
 coal. 
 
 No flux, properly so called, is employed in the fusion of refineries ; but several substances are occa- 
 sionally introduced, besides the air and charcoal, to act as chemical reagents. These are, for instance 
 the rich finery-cinder, the forge-cinder, oxides of iron and manganese, sand, and water. Of the finery 
 cinder, only that is useful which is formed after fusion is perfect, and while, in fact, the loop is about to 
 be drawn. This cinder falls to the lower part of the hearth : rich as they are, containing from 80 to 
 90 per cent, of magnetic oxide, they are not displaced by the iron, and may be left in the hearth after 
 the loop is removed. If drawn, which need only be when they have accumulated to a great degree, 
 they must be tapped for very low down ; when tapped, they run and solidify slowly, and take, of 
 course, all forms readily. Their formation in the hearth is indicated by the silvery sparks in which 
 they are thrown out by the blast ; and they are recognizable afterwards by their weight and semi- 
 metallic lustre. These present to the refiner the best reagent for coagulating the melted metal and 
 bringing it to nature. A part of these, also, are apt to adhere to the loop, from which they are broken 
 off and driven out by the hammer, and are very apt to be found mixed with the forge-cinder. 
 
 The oxides of iron and manganese are used mainly to save the metal which is otherwise supplied 
 from the pig under treatment to form cinders. Sand is used sometimes (and acting then like a flux) 
 to retain the metal in fusion ; but this is bad economy, both for quantity and quality. And water, 
 although its principal effect may be in saving fuel, as mentioned a while ago, yet acts as an oxidating 
 agent too. 
 
 When the pig contains sulphur or phosphorus in any appreciable proportions, (which give red-short 
 and cold-short iron respectively,) carbonate of lime, as pure as possible, may be added ; and the more 
 comminuted, the better. It should be applied when fusion is commencing, and not afterwards. In the 
 Pomeranian forges at Torgelow, about ten per cent, of limestone is added after fusion is complete, in 
 three different operations, each of which implies a stoppage of the blast and a stirring of the pig. It is 
 
IRON. 
 
 117 
 
 very successful in one respect — that the phosphorus, which exists in the pig at an average of 41 per 
 cent., is reduced, in the malleable metal, to | per cent. ; but it is at a considerable waste of iron and 
 fuel. Other alkalies have been tried, such as the carbonates of soda and of potash, with and without 
 lime, but without much encouragement. In theory, carbonate of magnesia would be the best cor- 
 rective. 
 
 (a.) The modes which are introduced under this method are, in some minute respects, almost as nu- 
 merous as the localities where it is applied. Karsten has enumerated and described sixteen different 
 processes, of which eleven are effected by a single fusion, and five by a double fusion. But the general 
 type of all is the so-called German method , which is spread over the whole of North Germany, widely 
 used in France, and, in many respects, exemplified in the bloomeries of the United States, especially in 
 Pennsylvania. The hearths used for this method, except the large chimneys under which they are 
 set, and which must, of course, have suitable foundations, so much resemble the Catalan forges, as not 
 to need a figure. Only some of the processes followed will be spoken of. 
 
 To work advantageously, the workman must know the pig-metal he is using, for so much is depend- 
 ent on management. Generally, a mixture is better than any one kind. Forge-pigs ought to be run 
 slender, both that they may be broken easier, and that they may be proportioned more exactly. The 
 fragments should not be too large, to waste fuel, nor too small, to run too quick. The quantity for one 
 heat will, of course, depend upon the particular case : as an average, it may be taken from 250 to 350 
 lbs. The best charcoal is that from soft woods, (for instance, the pinus alba, larix, strobus, &c.,) and it 
 should not be broken into pieces smaller than one’s fist. The quantity of blast varies with the quality 
 of metal and weight of fuel and charge, and also at different times of the operation. This last varia- 
 tion, unlike the high-furnace, must be under the constant vigilance and control of the workman. It is 
 usual to put more pressure on with white than gray iron ; a practice which does not arise so much from 
 the chemical condition requisite as from the habitual mechanical arrangement — of placing gray iron 
 nearer the tuyere. With an average charge, there will be required, while the melting is taking place, 
 about 150 cubic feet of air per minute ; while stirring, about 225 cubic feet; and while making the 
 loop, as much as 275 cubic feet per minute. In cases where the loop is made by attachment, as it is 
 termed, as much as 400 cubic feet is used per minute. 
 
 This word, loop, has been already used here frequently : it is only the French loupe, (a wen, a lump,) 
 applicable to the shape of the mass. The Germans call it blume, (a flower — because it resembles the 
 unopened corol of a campanulate flower,) from which we get our English word bloom — applied, in our 
 language more particularly, to what has been under the hammer and has been forged. The term loop 
 is more appropriate before forging. The French word renarditre, by which these forge-fires are called, 
 means, literally, a blind ditch through which water escapes ; and the analogy may be supposed with 
 the filtering and disappearance of the melted metal. The name has no relation to that of the animal 
 (the fox) whose kennel, or earth, it also is applied to signify. 
 
 To prevent the charge from attaching itself, in fusion, to the cast-iron sides, and especially the bot- 
 tom of the hearth, an arrangement is usually made by which water can be applied to the outside of 
 these to cool them. This should be judiciously resorted to, when necessary ; particularly in the case or 
 the bottom-plate, to avoid breaking it — which would result not only in its own loss, but likewise in that 
 of the charge for that heat. It is better to dispense with water after the fusion is complete. 
 
 The slope of the sides and inclination of the bottom, varying in different forges, and strongly insisted 
 on by some metallurgists, appear chemically of absolute indifference. There is a mechanical advan- 
 tage, only, in the ease of working and lifting the loop. But in the direction and pressure of the blast, 
 and the size of the tuyfere, (or tue-iron, as the American workmen call it,) the chemical results, both as 
 to quantity and quality, are largely bound up. In former times, there were used two different tuyhres, 
 i. e., the blast was admitted through more than one orifice : a more correct observation has reduced 
 them, almost universally, to one tuyere. The nozzle of the tuyhre is frequently of cast or wrought iron, 
 which can be easily fitted on the copper pipe. It is usually semicircular — sometimes round, or oval ; 
 and its area will not surpass 1£ square inches. The inclination of the tuyere varies from 5 to 10 de- 
 grees downwards from the horizon. Were it horizontal, it would burn away more fuel, and a part of 
 the blast would be lost. The more depressed the tuyhre, the longer the metal remains liquid ; the 
 more horizontal it is, the sooner the metal passes to the malleable state. White iron, then, which has 
 this last tendency in itself, requires a more depressed tuyhre than gray non — although some (Metallur- 
 gists assert the contrary. The depth of the hearth — i. e., the distance between the bottom-plate and 
 the upper edge of the tuyere — is manifestly correlative with the depression of the latter ; and they 
 should work together. A hearth should not be shallower than 7 inches, nor exceed 10 inches. When 
 the proportions are established, the tuyere is fixed, by cramps or otherwise built in as firmly as the 
 sides of the hearth, to prevent derangements that would be sure to accrue upon its accidental dis- 
 location. 
 
 After covering the hearth with fuel, (leaving there, or not, the cinder of a former heat,) and getting 
 up a good heat, the pigs are pushed in the hearth to about 6 or 8 inches of the tuyere, (the grayer the 
 iron, the nearer it is placed,) covered with charcoal, the blast put on, and every thing done to promote 
 fusion. When they have begun to melt, the workman sounds with his bar to feel the consistency of 
 the fused mass ; and he judges by that whether cinder requires to be let off, and what is the state of 
 crudity of the metal. When the latter begins to be stiff and pasty, he draws the mass towards the 
 counter, and, clearing away the charcoal and cinder to expose its surface, lifts it out upon his ringer. 
 It generally breaks into several pieces, which he draws from the fire, supplies fresh fuel, and then re- 
 places the pieces in the inverse order of their conversion ; i. e., the most crude nearest the tuyere. 
 They are fused again as before, again worked and lifted. This time, generally, they remain coherent, and 
 the metal is sufficiently refined. Sometimes, however, a third fusion is necessary. The liftings which 
 have been made hitherto, have only been up to, or a little above, the surface of the melted cinder ; ac- 
 cording as the workman judges it necessary to have the strongly oxidating influence of the blast, or the 
 
118 
 
 IRON. 
 
 more gentle reaction of the scoriae. But in making up the loop, it is lifted quite above the tuyfcre, so 
 that the air may pass under and around it ; it is turned upside down, and end for end, to expose every 
 part of it, and then redeposited in the hearth, where the cinder is drawn to one side. It is covered 
 with fresh fuel, the blast is strongly urged, and the loop is kept at a temperature almost of fusion, 
 completely to decarburate and purify it. This result is judged of by plunging a ringer into the loop 
 after the blast has been gradually diminished : if the thimble, which comes out upon the ringer, is 
 easily detached after cooling, the metal is refined, and the loop is then taken out to be shingled. 
 
 The number of workmen required is generally five, including the hammer-man; the time taken to 
 finish a loop from 3 to 4 hours. But there is always extra time lost in preparations, <fec. ; so that a 
 better calculation would be to say that in the week of six days, an average forge will turn out from 4 
 to 5 tons of large merchant-bars, say 2 inches square ; or about 3 tons of inch -square bars. The aver- 
 age waste will be about 27 per cent, of the crude iron ; and the fuel used will be, at a mean, about ISO 
 for 100 of bar-iron. 
 
 This process is, perhaps, the best for the quality of the bars produced ; in respect to quantity, how- 
 ever, waste and fuel, it is among the least economical. In this last regard, of all the existing European 
 processes, that of Sregen appears the most advantageous, the quantity of bar (of large size, to be sure) 
 amounting to 9 and 10 tons per week, the average waste about 20 per cent., and the fuel, weight for 
 weight of bar produced. 
 
 (b.) This, which is the method used in Champagne, and extensively in America, substitutes a rever- 
 beratory or air-furnace for an open forge-fire, urged by a direct blast ; and, in fact, leaves the workman 
 to do by manual labor what was done partly in the preceding method by chemical reagents. From a 
 supposed analogy between the manipulations here, the behavior of the material, <fec., and what was 
 familiar in the preparation of clay to prevent the passage of water to foundations, &c., the process re- 
 ceived the name of puddling ; as the other method is sometimes called boiling. As in this a higher 
 temperature is necessary, (heated air being the only reagent,) a fuel giving more heat is required, and 
 therefore coal is used. The metal, however, was at first, and is largely still, charcoal iron ; prepared 
 in advance, both in form and substance, for the final refining it has to undergo. This preparation is a 
 conversion into white iron ; which is done either at the high-furnace or by a second fusion. If the first 
 is relied on, the crude iron should be run into plates, or very flat pigs, to whiten it thoroughly. The 
 Styrian method for this purpose is a curious one. The crude iron is run at once into an oval pit, or 
 basin, in sand ; the cinder is cleared off, and water is sprinkled over the yet liquid metal to chill it. 
 In this way, plate after plate, weighing from 25 to 50 lbs. each, is formed in intervals of hardly a minute. 
 Only gray iron, from fusible materials, will chill in this way. The plates thus made are roasted, i. e., 
 exposed for 10 or 12 hours to a red-heat, either in an appropriate oven or in an open pile; by which 
 they are slowly decarburated. If this operation of roasting were in any case well performed, a great 
 leal of the carbon should be got rid of; but the expense of fuel is very considerable. 
 
 The second fusion to whiten iron, is what the French term mazeage, and the English running out or 
 fining. This is very much such a process and in such a furnace as has been described under the former 
 method of refining, only it is not carried so far, and the metal, instead of being lifted and looped, is run 
 into plates. The waste in this operation is from 5 to 7 per cent, on the crude iron: mazeage, proper, 
 is done with charcoal. 
 
 The reverberatory furnace used is similar in form to what has been already figured under a former 
 section. 
 
 (c.) The constant combination of a finery, where the plate-metal is produced with coke, and a rever- 
 •' raiory furnace, where it is puddled with coal, constitutes the method practised in England ; and there, 
 
IRON. 
 
 119 
 
 as elsewhere, is more or less appropriate and even necessary, whenever iron is to be produced in great 
 quantity, and fossil fuel is of course to be relied on. 
 
 Fig. 2398 is a ground plan, on a scale of l-25th of the actual size, of an English finely, blown with six 
 tuyeres. In this aaaa indicate the places of the cast-iron columns on which the chimney rests; b b 
 <fec., are the side-plates of the forge ; h is the hearth formed by the water-backs ioww; f is the front 
 plate, and p the mould in which the plates are run; cc are troughs where the bars are cooled. 
 
 Fig. 2399 is a half vertical section of the same plan, drawn to the same scale, and serving to explain 
 it. This last figure also shows the attachment of the blast, which, to save room, was left off from the 
 other ; as well as, by the dotted lines in the hatched space beneath, the mode of securing the sustaining 
 columns in a mass of masonry. The right half-section would be a counterpart of this. 
 
 Fig. 2400 is a longitudinal section of the air-box r ; and 
 the dotted circles on its face are the ports by which the 
 blast is conducted to the several tuyeres. The lever- 
 valve allows the blast (which in these establishments 
 comes generally from the great blowing-engines of the 
 liigh-furnaces) to be regulated by the workman. 
 
 Fig. 2401 is a section, still upon the same scale, of the 
 plate-mould p. The earlier fineries were blown only on 
 one side, and with three tuyferes ; the modern ones, almost 
 universally, are blown with four or six tuyferes, with a 
 cross blast. The crude iron intended for the finery 
 should, like that for the fires already spoken of, be run 
 into small pigs. They very frequently, however, are 
 employed weighing from 100 to 120 lbs. 
 
 The kind of coke to be preferred varies with the quality of the metal. When this last is refractory 
 the coke should be heavy and compact. A friable coke, and one containing much earthy matter, as 
 well as oven coke generally, are objectionable. 
 
 The sole or bottom of the hearth is indicated on Fig. 2399 by the letter s, 2401. * 
 
 and by a different species of hachures. This reposes upon fire-brick or 
 refractory sandstone ; and is best made of a layer, 4 or 5 inches thick, of — -■,■■■■. . . 
 
 broken quartz, well rammed. At the first heat, this layer is partially melted 
 and jjercolated by the metal, forming a bottom exceedingly hard and refrac- * 
 
 tory. This property, in expediting the work, compensates fully the waste of metal in the beginning. 
 From time to time, however, it requires replacement. The most convenient way to get it out (for it 
 weighs often a couple of tons) is, upon the conclusion of the week’s work, and after the last heat, to 
 throw water upon it while yet red-hot. This cracks it up and renders it easy to be taken out ; the 
 water-backs may then be reset, and the bottom laid anew. The old bottom, which contains a good 
 deal of half-refined iron, can be used up, little by little, as scrap. 
 
 As the object of this process is to fuse tire metal, the tools and working are only fitted to that end. 
 It is rare that any flux or reagents are added. Hard metal is heated sometimes with forge-cinder or 
 finery-cinder. These, as well as any thing else that may be used, act in nearly the same manner as 
 in refineries with charcoal. 
 
 The plate-mould, which can be added to, from its construction, at pleasure, should be so long in pro- 
 portion to the charge, (which, for a large hearth, will be, on an average, 1^ tons,) that the plates are 
 left not more than 1|- or 2 inches thick. After the metal is in the mould, water is thrown copiously 
 upon the cinder which has run out with and covers it, and which, by this, is easily separated. The 
 plate itself, after being chilled with water, is broken up for the next process. 
 
 Care must be taken, in this, to strike a proper medium between doing too much and doing too little. 
 If the metal in the run-out sparkles little, and, after being cool, preserves its compacity, it has not 
 been fined enough, and the puddling will be hard and long. If in the run-out it disengages, on the 
 contrary, a multitude of faint sparks, so confluent as to become a sort of flame, and emits a white 
 vapor, it will probably be found converted partly into malleable iron ; and the puddling, in this case, 
 will be more difficult and wasteful than in the other. 
 
 These results depend, in a measure, upon the supply of blast — which should vary according to the 
 quality of iron, and also according to the character of the fuel with which it has been produced in the 
 high-furnace. With charcoal iron, each tuyfere should furnish from 200 to 250 cubic feet per minute, 
 under a pressure of 2 lbs. per square inch. With coke iron, the quantity may advantageously be raised 
 to 300 cubic feet, and the pressure to 2^- lbs. 
 
 With this supply, a finery such as described will run out rather more than a ton per hour ; and ten 
 heats mav be made a turn of twelve hours. The waste should not be more than 12 per cent, of crude 
 iron ; and the coke used, about 30 per cent, of the weight of metal charged. 
 
 From the finery, the metal is ready to be passed to the puddling- furnace. This resembles so much, 
 in shape and detail, the reverberatory furnaces before given, as not to require a figure. Sometimes it 
 is used with a charging-door on each side, when it is said to be a double furnace. In some cases, the 
 two doors have been placed on the same side ; but, as they could not be worked exactly together, their 
 alternations tended to produce irregularities and waste. There is a furnace of this kind, however, 
 though with a different aim, which is affirmed to be very convenient and economical. It is a two- 
 hearthed arrangement, which will be made sufficiently clear by the sketch, in longitudinal section, (Fig. 
 2402,) where g is opposite to the grate, p to the hearth for puddling, c to the cinder-pit, li to the hearth 
 for heating, and d to the smoke-flue. On the hearth h, the metal undergoes a roasting and partial re- 
 fining before it is removed top. The external fixtures, the pulleys and counterpoises for the doors, the 
 travelling stirrup for shifting the charge, etc., can be very easily imagined. That this furnace would 
 save fuel is quite probable, but, in respect to other conditions, its efficacy is more problematical. 
 
120 
 
 IRON. 
 
 These conditions for puddling would seem to be, 1st, that a sufficient heat be obtainable to melt the 
 metal entirely ; 2d, that the heat, in whatever degree availed of, should be uniformly distributed over 
 the hearth ; 3d, that there should be 'no carbon unconsumed in the flame, in contact or to be combined 
 
 with the metal, which contains enough of that impurity already ; and, 4th, that the metal (and this is 
 more important for fine metal) should not be exposed to a too oxidating effect of the air which is 
 aspersed through the grate. 
 
 As yet, bituminous coal is the best fuel that can be applied in a puddling-furnace. Anthracite is 
 also used in America, with better results than have been experienced in Europe. Charcoal and wood 
 also have been tried, but do not appear to diminish the waste or improve the quality of the metal, 
 while the cost of fuel is enhanced. The hearths are supposed, also, to be more difficult to maintain 
 with these last. 
 
 This maintenance is one of the points of trouble and expense ; and various methods are resorted to 
 for the purpose in constructing the hearth. It is sometimes made of cast-iron ; in which case it is cov- 
 ered with a layer of cinder 1-J to 2 inches thick, well pounded, and melted down before the metal is 
 charged. Others prefer to make it of sand, or broken quartz, from 6 to 8 inches thick, well rammed, 
 and covered then with a thin coating (less than an inch) of powdered cinder, which is melted and 
 smoothed before charging. This method is ordinarily productive of more waste, for the silica takes up 
 portions of the oxide which is formed : with impure metal, (containing phosphorus, for instance,) the 
 silica aids in refining it. Others, again, use cinder entirely for the hearth ; stratifying it in small frag 
 ments to a depth of 5 or 6 inches, and then fusing it and smoothing down. In working only fine metal 
 of good quality, the tendency of the hearth is to thicken itself and change shape upwards ; when it is 
 of bad quality, (and still more when crude iron is puddled by the first operation,) the hearth becomes 
 burnt out, as it were, and hollowed downwards. Either change of shape renders repair necessary. Old 
 hearths in sand or cinder, which have been melted out or broken up, can be used advantageously in 
 making new ones. Limestone hearths have also been tried, to the improvement of certain kinds of 
 metal, but to the speedy destruction of the in-walls. 
 
 Before charging the furnace, a full red heat is got up inside, principally to save the waste that would 
 follow the oxidation by a slower fusion. Then the fine metal, broken up into pieces, which should not 
 exceed 28 lbs. apiece, and the smaller the better, is charged — hot from the smaller hearth, if the fur- 
 nace, Fig. 2402, is used — otherwise cold. Ordinarily, the whole charge is about 400 lbs. The register is 
 then raised, and the heat urged for about a quarter of an hour, when the mass becomes pasty, as the 
 workman can judge by feeling it with his bar. If the metal is charged hot, this ordinarily occurs in 10 
 minutes ; longer, if it was put in cold. If it gets too liquid in that period, water is injected to cool it. 
 The register is let down when it is at a proper viscidity ; and the workman, introducing his ringer, 
 works the pasty mass continually, to disengage the carbon. As this passes off, the metal becomes 
 more stiff, but it still must be worked, as before, to present the oxidated portions to those that may yet 
 be carburetted, and to prevent too great oxidation, or, as the workmen accurately term it, burning. 
 Sometimes it becomes so thick as to be incapable of being worked and divided : in such case, the ex- 
 ternal air must be shut off, the register lifted, and its consistence destroyed again by fresh urgency of 
 heat. If this misfortune does not happen, the thickened condition is followed shortly by an apparent 
 boiling, more or less marked, and an escape of oxide of carbon, burning with a blue flame. These ap- 
 pearances gradually cease, and another epoch occurs, in the metal’s becoming easier to work — in fact, 
 short, or tending to break apart in small lumps. The departure of the last remaining portions of car- 
 bon is generally indicated by a more lively lustre, which is taken as an indication of its having become 
 malleable iron, or come to nature. A continued puddling for four or five minutes more increases its 
 shortness, and it becomes pulverulent almost — the particles of pure iron falling apart, because there is 
 not heat enough to weld them. 
 
 To afford this heat is the next step. The temperature, which, from the first pastiness the metal 
 assumed, has been kept as constant as possible, is urged intensely; and the puddler judges, by his 
 own experience, of the proper moment to commence rolling the matter into balls. If begun too soon, 
 it would not be sufficiently welded ; if postponed too long, the little fragments would have become 
 independent, and would refuse to weld at all. Taking the proper moment, and beginning with the 
 matter the nearest the fire, the puddler works it all up into five or six balls, (or even more, if the charge 
 is very large,) which he draws over towards the bridge. While making the last, he rolls it all over the 
 hearth to fuck up all stray metal. This balling is done sometimes by parting the mass into as many 
 equal parts as it may be intended to make balls, and working each separately ; or, by taking a small 
 
IRON. 
 
 121 
 
 portion at once, and augmenting by attachment, (i. e., as one would roll a snow-ball,) like one of the 
 modes spoken of before in refining with a forge-fire. The result in either case must be the same ; and 
 the care to have the balls well rounded and uniformly compact must be equal. The balls, when fin- 
 ished, are taken out with suitable tongs and carried to be shingled. 
 
 The operation of puddling crude iron directly does not differ materially, except in time and in the 
 occasional addition of cinder, from puddling fine metal. The latter, if charged cold, will be balled iu 
 about 1^ hours ; if hot, in 10 or 15 minutes sooner. The former, cold, will require nearer 2 hours. 
 Ordinarily, six heats will be made in a turn of 8 hours with fine metal, and four heats with pig. There 
 is, of course, more waste, in proportion, with pig than with fine metal. The exact loss cannot be con- 
 veniently known, because the balls go directly to the hammer, or roughing-rolls, and a part of the 
 measured waste occurs there. This last, however, will be tolerably constant ; and a fair estimate of the 
 waste of pig may be made at 15 per 100. With gray iron, it would be, probably, nearly 20 per 100. 
 The loss on fine metal should not exceed 10 per 100. The weight of fuel consumed is about equal to 
 that of fine metal puddled, and about 1-J- to 1 of pig puddled. But to compare the absolute economy 
 of the two processes in this respect, allowance must be made for the coke used in the fineries. This 
 was before stated at rather less than one-third of a ton of coke for one ton of pig fined — equivalent to 
 half a ton of raw coal. Allowing, besides, the waste, &c., in making this coke, we should probably 
 conclude that, in the item of fuel, puddling direct from the pig is cheaper than from fiue metal. In all 
 other respects, however, it is dearer ; aud the puddled iron made is rarely of such good quality. 
 
 The use of anthracite as a fuel for puddling was mentioned just now. In point of fact, the furnaces 
 in which it is applicable hardly belong to the present class of reverberatory, or aspiring ; since, to 
 maintain a sufficient combustion, a fan-blast, resembling what has been before described, has to be 
 resorted to. Fig. 2403 is a horizontal projection of the principal features of one of these anthracite 
 
 2403 . 
 
 puddling-furnaces ; in which f indicates the situation of the blast ; g the fire-grate, with d its filling- 
 door ; h the hearth, with pp its charging-doors, constituting a double furnace ; and c the flue into the 
 smoke-stack. The remaining details, fastenings, &c., are analogous to other puddling-furnaces, and can 
 easily be imagined. The ash-pit is, of course, closed up, and the blast passes into it by one or two 
 orifices. The grate is made to be about twice as deep as for bituminous coal — say 20 inches ; and, for 
 a double furnace, is about five feet long. The hearth is about six feet in diameter ; and the flue, to 
 reach the base of the chimney, pitches very much downwards. The height of the chimney, which, for 
 bituminous coal air-furnaces, is about 40 feet, is, in these, almost immaterial, since the draught is regu- 
 lated by the fans. 
 
 Among the modifications that have been proposed in the details of puddling-furnaces, may be men- 
 tioned one (a double one) planned by Mr. Overman, the author of one of the most recent treatises on 
 the manufacture of iron ; and designed principally for economy of maintenance and repair, in cases 
 where fusible reagents should be used for improving the iron. In this, the hearth, lozenge-shaped, is 
 enclosed by water-backs ; the sole is cast-iron, supported on pedestals, and allowing free circulation of 
 air underneath. It is said by *3 expert author to have worked “ exceedingly well in all cases in which 
 
 inferior hot or cold short iron, from heavy burden, is puddled But for gray metal of small burden, 
 
 particularly for all coke, stone-coal, or hot-blast iron, it is of questionable utility. For white metal it is 
 perfectly useless.” The candor of this account is an additional guaranty of its correctness. 
 
 With the puddling ends all the strictly chemical metallurgy of iron. The remaining processes of 
 forging, (whether they be effected by impact, or under the hammer — by pressure, as in the squeezer, 
 or by lamination, as in the roughing-rolls,) although necessary, to expel the remains of oxides and 
 earthy matters admixed with the metal, and essential to the production of fibrous wrought iron, are yet 
 only mechanical. 
 
 The hammers used at the Catalan forge-fires are yet of primitive construction. A head of cast or 
 wrought iron, or both, weighing from 600 to 800 lbs., is fixed, as well as may be, upon a helve of beech 
 or oak. This helve, or log, is 12 or 15 feet long, and 12 to 15 inches in diameter; not squared or 
 dressed, further than to stub off the projecting knots ; and fitted with trunnions in a stout and solid 
 wooden frame, to allow of movement up and down. This is effected by tilting the end downwards 
 with cams placed upon the circumference of a water-wheel, usually 10 or 12 feet in diameter, but only 
 about one foot wide. This wheel makes from 25 to 30 revolutions a minute ; and, there being usually 
 but four cams upon it, the strokes of the hammer, at a maximum, will be not more than 120. The 
 lower face of the hammer works upon an anvil of the same surface and same material, and weighing 
 from 450 to 550 lbs. The anvil is so inclined that the striking faces shall be parallel when in normal 
 position. These heavier hammers are used for shingling the loops, and even for drawing down a large- 
 sized bar. For smaller work, and for finishing, lighter hammers are used, arranged in the same man- 
 ner, but weighing from 150 to 180 lbs., with an anvil of 120 to 150 lbs., and worked by a smallei 
 wh«cl, of 6 to 8 feet, making 30 to 35 revolutions per minute, with, ordinarily. 6 cams ; so that the 
 
122 
 
 IRON. 
 
 strokes amount to 180 or even 200 in a minute. The skill of the hammer-man is shown by so man 
 aging the powerful implement at his disposal as to condense the bloom uniformly ; and his art, in fin 
 lsliing the bar to a uniform surface. 
 
 The hammers of the German forges were set with wood, in a wooden frame, like the Catalan ; only • 
 they are almost universally trip or lift hammers — i. e., the cam is applied between the centre of motion 
 and the anvil. This position has the awkwardness of sometimes embarrassing the hammer-man, and 
 makes it necessary that the helve be set obliquely in the framing. At the present day, more or less ot 
 the framing is made of cast-iron. The weight of these hammers is from 400 to 450 lbs. only ; the lift, 
 i. e., the vertical fall of the face, from 24 to 28 inches ; the wheel generally lias 5 cams ; and the num- 
 ber of strokes is from 90 to 100 per minute. 
 
 In the French forges the arrangement is the same, except that the heads are habitually heavier, 
 weighing from 650 to 150 lbs. ; the lift is not more than 20 inches ; and the stroke is slower, being from 
 *75 to 80 per minute. 
 
 In the forges of both countries, the finishing -hammers are tilted , both for convenience of access and 
 speed. These are of different sizes, according to the work to be done and the quality of the iron. The 
 larger ones weigh from 200 to 300 lbs., and make from 120 to 150 strokes per minute, with a fall of 
 18 or 20 inches ; the smaller range from 60 to 100 lbs. in weight, and make from 250 to 300 strokes in 
 a minute, with a fall of not more than 12 inches. To get up this speed, the water-wheel is furnished 
 with more cams, sometimes as many as 32 in number. All, the largest and smallest, work against a 
 sort of wooden spring, which checks their upward motion and imparts more momentum to the down- 
 ward fall. 
 
 Fig. 2404 is a projection, upon a scale of one-thirtieth, parallel to the plane of the water-wheel, of 
 (me of the modern German hammers, in an iron frame. The faces of the head and anvil are, in this, a 
 
 uniform plane ; but often, and especially for finishing hammers, the face is like the letter T relief 
 or else a full cross. 
 
 This modification is borrowed from the English fashion, whose hammers, besides, are altogether more 
 powerful and substantial. Made of iron throughout, the hammer-head and helve weigh from 4 to 7 
 tons. The lift is effected to a height of about 15 inches, by cams, which seize a projecting lip in ad- 
 vance of the very head, and constitute a trip-hammer proper ; sometimes by an eccentric, which works 
 against the helve between the head and the centre of motion. The number of strokes is about 80 or 90 
 per minute. The power is taken off from a steam-engine, and a heavy fly-wheel is necessary to equal- 
 ize the motion. The anvil weighs ordinarily from 4 to 5 tons. Fig. 2405 is a sketch of one of these 
 
 hammers ; the dotted lines showing that part of the arrangement which is below the floor-line and rests 
 upon the foundations. There are also lighter hammers, for special work, in the English forges, which 
 weigh altogether not more than two tons, and make from 140 to 180 strokes a minute. 
 
 With their heavy fly-wheels, these hammers cannot be stopped in the same way as the lighter ones 
 The usual mode is by thrusting a jack, or piece of iron, under the helve when it is at its highest. In 
 starting again, a piece of wood is dexterously placed to be caught by the cam, and the jack is released 
 
IRON. 
 
 123 
 
 Overman has suggested a permanent jack, (or jack-ketch,) to be worked by a piece of wire, which is 
 undoubtedly better. 
 
 A very ingenious and useful application of steam directly to a vertical hammer has been executed 
 by Mr. Nasmyth. Its behavior is not unlike that of a pile-driver ; only, it can be worked with great 
 rapidity, and thus, in some cases, dispenses with the number of reheatings necessary in finishing a bar. 
 As this machine is applicable to other purposes tliau the forging of iron, its description will be given 
 under a special article, Steam-Hammer. 
 
 Tie squeezers, which are extensively found in English iron-works, are employed for the same purpose 
 as the heavy shingling-hammers, viz., condensing the puddle-balls into slabs : they act, as might be 
 supposed by the name, by steady pressure instead of impact. They are supposed by some metal- 
 lurgists to answer the end of expelling the cinder, <fcc., as well as hammers ; but this is very doubtful. 
 As applied to finishing bars, their use would not be economical. The most numerous class is of tilt- 
 squeezers — i. e., the trunnions are between the power and the squeezing-jaws. The power is variously 
 applied, by an eccentric or by cranks. Fig. 2406 shows the chief features of one of the last kind, upon 
 a scale of one-fortieth of the actual size. The whole apparatus, which is of cast-iron, requires to be 
 strongly bolted down to a solid foundation. The dotted circle indicates the position of the fly-wheel, 
 by which the power is equalized on the crank ; and the shaded lines show the jaws, which are separate 
 plates of wrought or cast iron, bolted on the frame, and renewed when necessary. Such a machine, 
 making from 80 to 90 revolutions per minute, can squeeze about 100 tons per week. Its theoretical 
 deficiency is the want of parallel movement ; its practical one, the enormous strain (especially if the 
 loop should be too cold) upon all the blocks and journals. 
 
 A different apparatus from this, and free from some of its defects, is Burden’s patent eccentric rotary 
 squeezer — the mode of whose action will be apparent from the projection in Fig. 2407, where r shows 
 a cylinder with a roughened or serrated surface, revolving vertically in an eccentric drum which is per- 
 manent. The ball goes in at a , and is dragged round with it, more and more compressed in its narrow- 
 ing path, until it comes out at b. The bottom is a solid plate ; the top admits of a slight adjustment. 
 
 This machine has brought us round to the method, much older, and still practised in many English 
 establishments, of squeezing and condensing between horizontal cylinders, or roughing-rolls. A°suf- 
 ficiently indicative sketch of these is given in Fig. 2408, about one-fiftieth of the actual size. The 
 securings and couplings, Ac., are omitted. The first of the upper train on the right is moriscoed or 
 roughened, to catch and drag the ball. The next one is channelled for the same purpose. The sur- 
 face-adhesion is enough to that end in the other two. The collars on the lower train are for up-setting 
 or keeping the slab in shape laterally. 
 
 What are called roughing-rolls in America are used, not instead of, but subsequently to, the hammer 
 or squeezer ; and serve to forge the bloom into shape, rather than perfect its malleability. Instead, 
 therefore, of being flat, the cylinders have corresponding grooves of large size, making a square or 
 lozenge-like section. In other respects, in housing, geering, <fec., they are the same with the English. 
 
 In proportion as the. bloom or slab becomes drawn out by any of the condensing or flatting processes 
 which have been mentioned, it becomes necessary to shear it up into shorter lengths, which are reheated 
 sepai ately oi in piles, to be treated as before, lhe Catalan forges use a chisel under the hammer for 
 this purpose. But rough-bar is much better severed by heavy shears, worked 
 either by a water-wheel or steam-engine. Small bar can be cut with hand- 
 shears. In general arrangement, the heavy shears resemble the squeezers — 
 cutting-edges being substituted for the flattiDg-planes ; and, like the latter, 
 they are worked with a crank at the end of a straight or bent shank, or with 
 an eccentric that tilts the edges. The shank and shear-block are all of cast- 
 iron ; and the leverage, from the trunnions to the crank, wall vary from 4 
 to 10 feet, according to the work intended. The cutting-edges are of steel, 
 bolted ou to the block, and lie either in the same plane with the shank, or 
 parallel with the trunnions. The last mode has been devised, as obviating 
 the defect belonging to all scissors arrangement — viz., the varying ang’le o^ the cutting-planes. As 
 suitable for thin work to be cut evenly, a sketch of this arrangement is given in Fig. 2409. The 
 blades, which are shown by the vertically shaded lines, may be of any length— 15, or even 24 inches— 
 
 2109. 
 
 MilElig 
 
 
124 
 
 IRON. 
 
 suited to the character of the work to be cut. The defect in these, as in all existing shears, is 
 the want of horizontal slide as they come down vertically — a modification easier to imagine than 
 execute. 
 
 The reheating ox piling furnaces, which have been just now mentioned as necessary for restoring the 
 temperature to the slabs or bars, and enabling them to be further worked on and finished, are, in the 
 most complete establishments, separate fires. In the more primitive methods, this reheating (which is 
 required twice or thrice) is done in the forge-fires themselves ; sometimes it is done in the puddling- 
 fire, or at the end of the puddling-furnace. In general character, these reheating ovens resemble the 
 ordinary puddling-furnace ; but they require some modifications to yield their best effect. The aim of 
 these is to produce a welding heat uniformly over the hearth ; and, at the same time, at the expense of 
 as little metal oxidated as possible. The last end is answered by making the grate larger in proportion 
 to the hearth, and charging more fuel in proportion to the chimney, so that the air may be more com- 
 pletely deoxidized by the excess of carbon. The former is sought to be satisfied by lowering the 
 bridge and bringing down the arch nearer to the ramp, to which, also, the hearth proper inclines 
 little. Wood may be used in one of these furnaces, but with a larger grate and a lower arch. 
 
 The remaining machinery to be spoken 
 of is the cylinders or rolls tor finishing the 
 bars — flat, square, round, or in any fancy 
 section. The housing and coupling these 
 trains can be understood from the rough- 
 kig-rolls just now given, without a special 
 figure. All are arranged upon the same 
 principles ; only, the lighter the work the 
 longer may be the trains, and more rollers 
 in a train. The frames or housing for the 
 rolls are made of cast-iron, as seen in sec- 
 tion on Fig. 2410, which shows, on a scale 
 of one-twelfth, an assemblage of three cyl- 
 inders in a train, suitable for finishing light 
 bars. This section also serves to illustrate 
 Fig. 2408. These frames should, of course, 
 be set as solidly as possible ; for instance, 
 upon a cast-iron bed-plate, bolted to a tim- 
 ber foundation built in with masonry. This 
 seems better than masonry alone, because 
 of a certain elasticity in wood. If slots are 
 left in the bed-plate, the frames will be 
 found of easier adjustment. The bed-plate 
 should be open in the middle, leaving a 
 trench that may catch the cinder that comes 
 off from the bars, as well as the water that 
 drips on, and that may serve as a cellar to 
 the foundations. 
 
 For rolling flat bars, the cylinders are 
 grooved alternately and work reciprocally 
 in each other ; for round or square bars, 
 however, half their section is turned out of 
 each cylinder. The diameter in the one 
 case, and a diagonal in the other, correspond 
 with the normal surface of the cylinders 
 before being turned out. In turning out 
 grooves, ifcc., for fancy patterns, a good deal 
 of ingenuity is sometimes exercised, as will be seen in the descriptions and figures under the article 
 Railroad Bars. 
 
 The reciprocal fitting of the grooves for flat bars renders a longitudinal dislocation of the rolls impos- 
 sible. With the others, such dislocation is ordinarily sought to be guarded against by strong screws in 
 the frames ; but it is much better to have a groove and collar turned in one or both extremities of all 
 cylinders. Vertical displacement is prevented by the head-screw seen in the figure; and a lateral 
 adjustment is, in some cases, given by horizontal screws working through the trussing against the 
 plumber-blocks. There is usually a play of about a quarter of an inch allowed in the blocks and 
 couplings, to obviate immediate fracture in case of slight derangement ; and also to throw the breakage, 
 if an accident does occur, upon these parts rather than on the cylinders, which are the costly parts of 
 the machinery. It is easy to see that upon the truth of all the movements depend freedom from acci- 
 dent, and excellence and economy of work. It is, therefore, cheapest to have every thing made of the 
 best material and in the best manner. 
 
 In rolls for flat iron, the diameter of the cylinders is usually the same ; for round and square iron, 
 the upper cylinder is often a little (say half an inch) larger than the lower. If there are more than 
 two cylinders, the same practice is found, in some places, of making their diameters regularly decrease 
 (by say a quarter of an inch) from the upper to the lower. In others, and perhaps in the generality of 
 cases, the middle of the three is the largest. . Some metallurgists, on the contrary, object entirely to 
 this difference of diameter, as causing increased friction in the machinery, and straining the iron. This 
 objection is theoretically correct. The aim of the contrivance is to prevent the bar, as it passes through 
 the rolls, from curling around the upper cylinder ; if this last be larger, it will continue to bear on the 
 
IRON. 
 
 125 
 
 bar after the resistance of the lower roll has ceased, and will, of course, tend to force it down upon the 
 apron. But this tendency to curl is best corrected by having guards to each groove — i. e., wedges ot 
 wrought-iron, which catch the bar a9 it comes out. 
 
 The diameter of the cylinders, and their bearing, vary according to the purpose for which they are 
 intended. Roughing-rolls for puddle-balls are from 18 to 20 inches diameter, and 5 to 6 feet long ; for 
 piled iron or rough bars, from 12 to 14 inches diameter, and 5 feet long. Finishing-rolls for heavy bar 
 will be of the same diameter with the last, but from 12 to 18 inches shorter ; while for small rods their 
 diameter need not be more than 8 to 10 inches, and their bearing about 2-J feet. The weight of a pair 
 of roughing-rolls is from 4 to 5 tons, and of finishing- rolls from 1J to 2 tons. 
 
 In geering up the rolls, the lower one is the driver, when there are only two ; in a train of three rolls, 
 the middle one drives. The velocity of rotation varies according to size and purpose, and even accord- 
 ing to the state and quality of metal. Roughing-rolls should work slow : for puddle-balls 16 to 18 rev- 
 olutions, and for piled iron 22 to 24 revolutions per minute, are sufficiently rapid. For finishing-rolls, 
 this may be increased to 70 or 80 revolutions ; while small rods are rolled with 120, 150, and sometimes 
 even 200 revolutions per minute. But these high speeds are liable to frequent accidents. 
 
 The friction of the machine, and the initial temperature of the material to be rolled, heat the journals 
 and cylinders very much. To abate this a wooden trough is laid above the train, from which water may 
 drip on the machinery and metal under treatment. The effect is, to keep both the cylinders and metal 
 clean. 
 
 The size of the grooves, and their proportionate spacing, varies in different countries ; and the last 
 particular even in different establisliments. The methods for it are purely geometrical, and present 
 nothing peculiar in the manufacture of iron. The constant rule prevails here, as in all lamination, 
 viz., to place the largest grooves and the heaviest work nearest to the end at which the power is 
 applied. 
 
 With a single pair of cylinders the bar always enters on the same side. As it comes out on the 
 other, it is caught by a second workman, who, with the aid of a travelling-stirrup, hands it over the 
 rolls to the first. When the cylinders are triple, the rods enter alternately first on one side and then 
 on the other. The process with the single pair is time-consuming, but it does not seem likely to be 
 bettered, unless by having two trains parallel to each other, which would admit of the alternation of 
 entry as in the triple rolls. Such an arrangement would increase the first cost of machinery, but the 
 work would be done cheaper and better. 
 
 Such are the particulars which belong to the finishing of ordinary merchant- bars. The processes by 
 which iron is further prepared for special uses will be detailed more appropriately under separate 
 heads. Thus, the rolling of iron for railroads — an enormous branch of trade — will be treated under 
 Railroad Bars ; the lamination of plates and sheets, together with the further preparations for several 
 purposes that these undergo in the mill, will come under Sheet-Iron ; the cutting up of these in making 
 nails, hoops, &c., will be grouped under the head Slitting-Mill ; the extensive and remarkable appa- 
 ratus by which this reluctant metal is shaped with chisel' and drill, as if it were only wood, will be 
 described under the articles Lathe Planing-Machine, and Turning (of Iron;) and as far as relates to 
 the boring of cannon, under Ordnance ; the methods followed in drawing it out into Wire, will be ex- 
 plained under that title ; and, finally, under Smith-work will be contained all that class of operations 
 before indicated, which comprehend all the processes of hand-forging and welding, (as for anchors, 
 chains, horse shoes, <fcc.,) and of steeling and tempering, (as for cutlery, <fcc.,) practised in an art whose 
 exercise has originated the most extensive and well-known family name in the world. 
 
 History. — There is room here only for the indication of epochs signalized by inventions that have 
 given fresh impulses or new directions to the manufacture. From the earliest times till at least 800 
 A. D., the processes were either primitive, or, with unimportant modifications, gave only a more or less 
 malleable metal direct from the ores, which were necessarily those that fused readily. The fuel, origi- 
 nally wood, had been changed, during this period, to charcoal — though by whose ingenuity, or when, 
 there is no record. Some writers place about the termination of this era, which is that of Charlemagne, 
 the introduction of crude iron. This seems an antedating by at least four centuries. 
 
 •A. D. 1340. Earliest epoch of crude or cast-iron ; employed as ordnance by the Duke of Normandy, 
 afterwards John II. of France. 
 
 1490. Usual epoch of foundries. 
 
 1550. Epoch of wooden blowing-machines. 
 
 1612-19. Fossil-fuel (pit-coal) first used for reducing iron in England. 
 
 1640. Invention of trampes , or water-blasts. 
 
 1645-56. Epoch of foundries in America. 
 
 1740. Pit-coal and coke used in high-furnaces. 
 
 1749. Invention of rotary or fan-blasts. 
 
 1760. First cast-iron cylinder blowing-machine. 
 
 1780. Epoch of the puddling-furnace. 
 
 1784. Epoch of the rolling-mill. 
 
 1829. Discovery of the application of hot-blast. 
 
 1836. Application of the waste-gases from the high-furnace. 
 
 1837. Anthracite used as a fuel with hot-blast. , 
 
 During the intervals between these dates, and since the last, divers improvements, both in theory and 
 practice, have been suggested and executed, but none of them of palmary importance. 
 
 Statistics. — The following table, covering the last 10 years, contains what is known or can be esti- 
 mated in regard to Great Britain and the United States — the two principal producers and consumers in 
 the world : 
 
126 
 
 IRON. 
 
 Years. 
 
 Great Britain Manu- 
 facture. 
 
 UNITED STATES. 
 
 Manufacture. 
 
 Imported from Great Britain. 
 
 Crude Iron. 
 
 Bar Iron. 
 
 1840 
 
 1,396,000 tons. 
 
 286,000 tons. 
 
 5,516 tons. 
 
 32,829 tons. 
 
 1841 
 
 1,200,000 “ 
 
 250,000 “ 
 
 12,268 “ 
 
 63,056 “ 
 
 1842 
 
 1,088,000 “ 
 
 215,000 “ 
 
 18,694 “ 
 
 61,599 “ 
 
 1843 
 
 1,215,000 “ 
 
 350,000 “ 
 
 3,873 “ 
 
 15,758 “ 
 
 1844 
 
 1,210,000 “ 
 
 490,000 “ 
 
 14,944 “ 
 
 37,891 “ 
 
 1845 
 
 1,513,000 “ 
 
 625,000 “ 
 
 27,510 “ 
 
 51,189 “ 
 
 1846 
 
 1,675,000 “ 
 
 765,000 “ 
 
 24,188 “ 
 
 24,109 “ 
 
 1847 
 
 1,840,000 “ 
 
 800,000 “ 
 
 23,377 “ 
 
 32,085 “ 
 
 1848 
 
 1,999,000 “ 
 
 750,000 “ 
 
 51,632 “ 
 
 81,589 “ 
 
 1849 
 
 2,150,000 “ 
 
 600,000 “ 
 
 105,632 “ 
 
 173,457 “ 
 
 Tlie following table may be of interest as showing the range and relation of value and price in th* 
 two countries for the same period : 
 
 Years. 
 
 Average Valuation in 
 U. S. Custom-Houses. 
 
 Average Price of 
 Scotch Pig in 
 Glasgow. 
 
 Average Valuation in 
 U. S. Custom-Houses. 
 
 Price, at beginning of 
 Year, of Bar-Iron in 
 Liverpool. 
 
 1 S40 
 
 §21 per ton. 
 
 §19 per ton. 
 
 §52 per ton. 
 
 §43 per ton. 
 
 1841 
 
 18 
 
 16 
 
 35 
 
 37 
 
 1842 
 
 16 
 
 13 
 
 33 
 
 31 
 
 1843 
 
 12 
 
 10 
 
 32 
 
 25 “ 
 
 1844 
 
 13 
 
 13 
 
 28 
 
 24 “ 
 
 1845 
 
 18 
 
 21 “ 
 
 33 
 
 31 
 
 1846 
 
 20 “ 
 
 17 
 
 47 
 
 43 “ 
 
 1847 
 
 20 “ 
 
 16 
 
 53 
 
 46 “ 
 
 1848 
 
 16 “ 
 
 11 
 
 45 
 
 36 
 
 1849 
 
 13 
 
 10 
 
 35 
 
 28 “ 
 
 Sterling money is here converted, purposely, only to the nearest dollar. 
 
 Within the past ten years, of other countries only Belgium, France, Italy, and Prussia have extended 
 their manufacture of iron ; but the statistics of these which are accessible do not warrant a continuous 
 statement. It may be safely assumed, however, that the aggregate production of the world in 1849 did 
 not fall short of four millions of tons — an increase of 60 per cent, over 1839. Such, and so growing, 
 is the importance of this metal. 
 
 Bibliography. — Among ancient authors need be mentioned only Aristotle, Meteorolog., lib. iv., and 
 He mirab. Auscultate lib. ; Diodore of Sicily, Histor., lib. v. ; Strabo, Geograph ., libb. iv. v. x. ; of the 
 Greek writers : and of Latin, the elder Pliny, Hist. Natur., lib. xxxiv. In connection should be taken 
 Hausmann, de arte Ferri conficiendi veterum, 1820. In modem times, Agricola, de re Mrtallica, 1546 ; 
 Reaumur, Hart d’adoucir le fer fondu, etc., 1722; Swedenborg, Regnum Subterran., 1734; Bergman 
 de Analysi Ferri, 1781 ; and the Swede Rinman, Forsiik till jemets-historie, 1785, (Researches into the 
 History of Iron, and translated into German by Ivarsten,) — compose a clas9 who needed only a truer 
 chemical theory to direct and bind up their observations. Such a theory — begun to be exemplified in 
 the memoir of Berthollet, Vandermonde, and Monge, upon the different states of iron, Hist, de I'Acad. 
 des Sciences, 1786 — was more elaborated in the four quartos of Hassenfratz, La Siderotechnie , 1812; 
 and underwent a final establishment in Ivarsten’s Handbuch der Eisenhutten Kunde, first published ^n 
 1816, translated from a second German edition under the title of Metallurgie de Fer, by Culman, in 
 1830, and republished in a third German edition in 1844. Use has been made, in both of the last 
 editions, of the same author’s Metallurg. Reise dutch Baiern, etc., 1821. Other writers who since then 
 have contributed facts or explanations, will be mentioned chronologically : for instance, Berzelius, in 
 his Afhandlingar i Fysilc, Kemi, Ac., (a periodical begun in 1806,) where there are several important 
 announcements, which were subsequently collected and translated by Jlerve under the title of Chimie 
 de Fer, 1826 ; the same Berzelius in Manual of Chemistry, [Traite de Chimie, vol. iii.,) translated into 
 French by Jourdan ; Manson, Traite de Fer et de I’Acier, 1826 ; Pelouze, VArt du Maitre de Forges, 
 1827 ; Landrin, Manuel Complet du Maitre de Forges, 1829 ; Berthier, Essais par la Vote Seche, tom. 
 ii., 1834 ; Holland, Manufactures in Metal, vols. i. ii., 1834 ; Gnenyvean, Nouveaux Precedes pour 
 fabriquer la.Foute et le Fer , 1835 ; Dufrenoy, De Beaumont, Coste, and Perionnet, Voyage Metallur- 
 gique en Angleterre, (2d edition,) 1837 ; Le Blanc and Walter, Metallurgie Pratique du Fer, 1835— 3S ; 
 Scrivenor, History of the Iron Trade, 1839-41 ; Mushet, Papers on Iron and Steel, (being a collection 
 and revision of papers published many years before in Tillock’s Philos. Mag.,) 1840 ; Johnson, Anthra- 
 cite Iron, 1841 ; Alexander, Progress and Present State of the Manufacture of Iron, 1841, and an 
 edition of Rogers’s Letters on Iron- Making, 1844; Flachat, Barrault, and Petiet, Traite de la Fabrica- 
 tion de la Fonte et du Fer, 1846 ; and Overman, The Manufacture of Iron in all its various Branches . 
 1850. Authors who have treated of the mechanical resistance of this metal are, Duleau, sur la Resist- 
 ance du Fer forge, 1820; Tredgold, Essay on Cast-Iron, Ac., (2d edition, enlarged,) 1824, and with 
 additions by Hodgkinson, 1842-46 ; Turnbull, on Cast-Iron, 1832; Nuvier, Memoire sur les Fonts Sus- 
 ■pendus, 1830, and Resume des Lemons, Ac., (2d edition,) 1833 — in the first volume of which there is a 
 
IRON BLOOMING MACHINE. 
 
 127 
 
 copious collection of the results of preceding experimenters. Besides these, there are to be consulted 
 upon the theory and practice, upon the minerals, material, and manufacture of iron, papers in various 
 scientific journals which can only be generally indicated: for example, in the Ann. de Chimie et de Phy- 
 sique of Guyton-Morveau, Arago, Berthier, Thenard, &c. ; in the Journal des Alines of Collet Descotils, 
 Yauquelin, &c. ; in the Annale des Mines of D’Aubuisson, Bunsen, Ebelmen, Thirria, &c. ; in the An- 
 nalen of Poggendorff, of Mosander, Rose, and Seebeck ; in the Archiv. fur Bergbau of Karsten , of Berze- 
 lius, and Karsten ; in the Phil. Transact., and in the L. and E. Philosoph. Mag. of Rennie and Daniell, 
 Ac. : many of which would require examination and discussion in a complete modern treatise on iron. 
 
 Improved Machines for the Manufacture of Iron . — Various machines have been contrived for the 
 squeezing out the cinder from the puddle ball ; the best is probably the hammer, and it is generally 
 used in the manufacture of the best iron. A common form of squeezers called the alligator is shown 
 
 2411. 
 
 2413. 
 
 fig. 2406, an improvement over the “ Burden’s Patent Eccentric Rotatory Squeezers,” illustrated in fig. 
 2407. A machine somewhat similar in its action, will be found under the head of Puddlf.r’s Balls. 
 
 Figs. 2411, 2412, and 2413, illustrate an English machine, patented by Mr. Jeremiah Brown, and in- 
 tended to serve the same purpose. The machine consists of three large eccentric rollers a, b, c, placed 
 horizontally in the strong holsters d d, the centres of the rollers being arranged in a triangular position 
 and the bottom roller c, nearly central between the two top rollers a, b : these rollers rotate in the same 
 direction as shown by the arrows, and are driven by a centre pinion e, working into three pinions of 
 equal stzefff fixed on the roller spindles. In the present machine, the driving power is applied direct 
 to the bottom roller, by means of the large wheel g, for the convenience of carrying the main shaft un- 
 der the floor, but it could be applied to the centre pinion if preferred. The rollers are cast solid, with 
 their journals like ordinany rollers, and are driven in the usual manner by coupling boxes and spindles 
 li h. The roller faces are sixteen inches long, and the bottom roller has strong flanges at each end 8 
 inches deep, between which the two upper rollers work ; the object of these flanges is to upset or com- 
 press the ends of the bloom, as the iron in the operation is elongated, and the ends are forced against the 
 flanges which make them square and 
 sound. The top roller a has a large 
 hollow, in which the puddled ball i is 
 placed by the puddler ; and this roller . 
 carries the ball round, and drops it Jj 
 into the space between the three ; o 
 rollers, as shown in fig. 2412, this ; - 
 space being at that moment at its 
 largest capacity. The three project- 
 ing points k k k, of the rollers imme- 
 diately impinge upon the ball, and 
 compress it forcibly on the three 
 sides, and, giving a rotating motion 
 to the ball at the same time, they 
 have a very powerful kneading action 
 upon the iron, squeezing out the cin- 
 der very effectually, which flows 
 freely away, down each side of the 
 bottom roller. The space between 
 the rollers gradually contracts, from 
 
 the eccentric or spiral form of the rollers, thereby maintaining an increasing compression on the iron 
 on all sides and the ends, until it is liberated by the points III simultaneously passing the bloom m, 
 which falls down in the direction of the arrow and is discharged from the machine at the same moment 
 that another ball is dropped in at the top of the machine. The projecting teeth on the surface of the 
 rollers assist this action, by seizing hold of the iron and kneading into it as it rotates ; and these teeth 
 gradually diminish in projection, the last portion of each roller being plain, and the bloom is conse- 
 quently turned out in a smooth compact form. The space between the flanges of the bottom roller is 
 
128 
 
 IRON ROLLING MACHINE. 
 
 widened for a sliort distance beyond the point l, for the purpose of allowing the bloom to drop out read* 
 ily, and admitting the fresh hall. 
 
 A provision is made to prevent risk of breaking the rollers by any unusual size of ball being put in, 
 by means of the two large triple-threaded screws n re, which bear upon the journals of one of the top 
 rollers b ; a small pinion on the head of each of these screws works into a large pinion fixed between 
 them, which has a horizontal lever fixed to it, carrying a balance weight o at the end ; this weight 
 causes a constant equal pressure on the roller, and in the case of any hall of extra size being put into 
 the machine, the screws yield by turning back and lifting the weight to the extent that maybe required, 
 so that a large ball will be worked with the same pressure and in the same effective manner as the 
 smaller sizes. A continual supply of water is run on to all the journals throughout the machine, Which 
 prevents any possibility of the journals becoming hot, even when the machine is in constant work. 
 
 IRON ROLLING MACHINE — Clay’s improvement. We copy from the inventor’s specification: 
 
 My invention of certain improvements in machinery, for rolling iron or other metals, is designed la 
 
IRON ROLLING MACHINE. 
 
 129 
 
 produce, by the process of rolling, bars of taper forms, as for instance wedge-shaped bars or conical 
 bars. 
 
 The tapering of metal bars I effect by allowing one of the shaping-rollers to recede gradually frorr 
 the other, as the rolling operation goes on, and thus enlarge the space or distance between the rollers, 
 
 2416. 2415. 
 
130 
 
 IRON ROLLING MACHINE. 
 
 are allowed to relax their resistance by a slow and gradual escape of the fluid from the cylinder, 01 
 chamber through an adjustable valve. The apparatus I have arranged for this purpose is shown in the 
 accompanying drawings, in which fig. 2414 represents a vertical section, taken transversely through the 
 head of one of the standards, wherein the bearings of the journals of the rollers are mounted, showing 
 the piston, its rod and appendages, with the column of water against which the piston bears, and the 
 valve, whereby a small quantity of the fluid may be allowed gradually to escape. Fig. 2415 represents 
 a partial front view of the rollers, the bearings, and part of the regulating apparatus in the head of the 
 standard, being shown in section. 
 
 Of course, it will be understood that two such standards support the ends of the rollers. Fig. 241 G 
 is a horizontal section, taken in the line 1, 2, of fig. 2414, showing the parts inverted, or as seen from 
 below ; and fig. 2417 is another horizontal section, taken on the upper side in the line 3, 4, of fig. 2414, 
 showing the entrance and exit valves of the chamber of water, and the means of working or regulating 
 the exit valve. In the rolling-mills usually employed for rolling bar-iron, the rollers are generally 
 mounted in fixed bearings, or bearings which during the operation of rolling, are rendered immovable, 
 by being maintained in their places by strong screws or bolts. 
 
 In my improved machinery, or apparatus, the ends of the bearing A, of the upper roller, are let into 
 grooves in the standards, as in ordinary rolling-mills, in such a manner as to admit of their sliding up 
 and down therein, in order that, by so sliding, the parallel distances between the rollers may he allowed 
 to change. 
 
 The rising of the bearings with the upper roller is regulated and governed by a piston-rod a , which 
 rests on the top of the bearirigs, the upper end of the piston-rod being connected to the solid piston b, of 
 the hydraulic cylinder, or water-chamber c, as shown in figs. 2414 and 2415. 
 
 This cylinder c, is filled with water, or other non-elastic fluid or liquid, and is furnished with leather 
 or other suitable packing, for the purpose of preventing any leakage of the water. 
 
 The packing is kept in its place by a metallic ring or plate <1, which is firmly secured to the body of 
 the cylinder by strong screw-bolts. 
 
 The cylinder is supplied with water from any convenient source, by a lateral tube p, shown in fig. 
 2417, through the rising feed-valve e, the construction and operation of which will be clearly under- 
 stood by referring to the drawing. 
 
 f is the exit-valve, through which, when partially opened, the water is allowed to escape from the 
 chamber c, on pressure being applied to the lower end of the rod a, by which pressure the piston b will 
 be made to rise and partially to expel the water, as will be the case when a bar of iron is passed between 
 the shaping rollers B B. The valve f is constructed in such a manner that the opening for the dis- 
 charge of the water may be regulated with the greatest exactness by merely advancing or receding the 
 plug g, worked by the screw at its back end, the effect of which will be to open or close the valve to 
 any extent that may be required. 
 
 There is a slight spring behind the plug y, which is merely intended to push it forward and close the 
 aperture of the valve when the upward pressure of the piston is not in action, as will be the case when 
 the rolling operation is suspended. An additional valve h , is also made to communicate with the exit- 
 passage i. This valve, however, is always kept closed by a strong spring, as shown, and will never allow 
 any water to escape this way from the cylinder, except when any extraordinary pressure takes place, at 
 which time the power of the spring will be overcome, and, by yielding, prevent the machinery from 
 being too greatly strained. 
 
 In introducing into my improved machinery a mass of iron between the shaping-rollers, say for the 
 purpose of producing a wedge-formed bar, having parallel edges, I employ a pair of rollers of the ordi- 
 nary kind, having the grooves and flanges, as shown in fig. 2415. 
 
 The mass of iron being about to be introduced between the rollers in the first groove, I open the valve 
 /, by withdrawing the screw behind the plug g to such an extent as will allow the escape of water from 
 the chamber c in a small current, regulating the opening for the intended discharge according to the 
 required taper of the bar to be formed, the required extent of which opening will readily be found by 
 the experience of the workman. The operation of rolling now proceeding, the pressure of the metal 
 passing between the rollers will cause the bearings of the upper roller to rise and force up the piston- 
 rod a , in doing which the piston will be made to rise in the chamber c. But the ascent of the piston 
 being resisted by the non-elastic fluid in the chamber e, the escape of water through the valve /and 
 outlet i must take place to allow of the ascent of the piston, and consequently the separation of the 
 rollers : according, therefore, to the rate of the escape of water will the taper or inclined shape of the 
 bar to be produced be determined. 
 
 It will thus be seen that, by my improved apparatus, the process of rolling metals is carried on much 
 in the usual manner, except that, by means of opening the valve more or less, the escape of the water 
 from the chamber will allow the upper roller to rise, and consequently give the requisite taper form to 
 the bar under operation, according to the rapidity with which the water is allowed to flow out of the 
 chamber. As I do not intend to confine myself to any particular forms of bars to be produced by my 
 improved machinery, it is not necessary to describe more precisely the shapes of the rollers. I will there- 
 fore only add, that by forming the grooves of the rollers in elliptical shapes, as at nn, in Fig. 4010, I 
 am enabled, by the gradual rise of one of the rollers, and repetitions of the rolling operation, to produce 
 bars of conical figures. 
 
 It is sometimes desirable to roll a bar taper or wedge-formed, for a portion of its length, and level for 
 the remainder of its length. 
 
 For this purpose, it will be necessary to allow the upper roller to rise to a certain distance only, and 
 then to stop. This I effect by means of adjusting-screws k k, one over each bearing of the rollers, similar 
 to those heretofore used, except that it is through the axes of the adjusting-screws, forming guides, that 
 the piston-rods a pass, as shown in the drawing at Fig. 2414; and it will, therefore, be understood that 
 
JACK, LEVER. 
 
 131 
 
 when, by the escape of the water from the chamber, the hearings of the rollers have been allowed tc 
 force up the piston-rod and the piston a certain determined distance, that then the upper edge of the 
 bearing A, of the top roller will come into contact with the under side of the adjusting-screw k, beyond 
 which it cannot rise, and as the hearings will, for a time, become fixed, the bar of iron under operation 
 will, for the remaining portion of the process, be rolled parallel. 
 
 The adjusting-screw k, passes through a hollow screw made in a socket fixed in the frame, and the 
 screw can he easily raised or lowered, so as to limit the rise of the hearing A, by merely turning the 
 hand-wheel l, attached to its lower part. 
 
 It may he as well to observe that the standards or housings may he of any convenient known pattern, 
 and that a lever or other known balance may be used with advantage to support the roller in its rise and 
 fall. A portion, also, of the head of the standard in which the piston works is made removable for the pur- 
 pose of getting at the piston and packing when required, as will be seen at q q, in figs. 2415 and 2416. 
 
 JACK. In mechanics, a sort of crane for raising heavy weights. It consists, first, of a small pinion 
 wrought with a common winch. This pinion works in the teeth of a large wheel, on whose axis there 
 is fixed a small pinion with teeth, working in a rack. The turning of the -handle raises the rack, and of 
 course any weight attached to it. If the length of the handle of the winch be 7 inches, and the pinion 
 which it drives contain 4 leaves, working in the teeth of the large wheel having 20 teeth, then will 6 
 turns of the handle be requisite for one of the wheel. But the length of the arm of the winch being 7 
 inches, the circumference through which the handle moves will be about 44 inches, and for one turn of 
 the wheel the handle must pass through 5 X 44 = 220. The wheel carries a pinion of. say, 3 leaves, 
 of a pitch of -j of an inch, working the rack that carries the weight ; one turn of the pinion will, there- 
 fore, raise the rack one inch, and as the power moves through 220 in the same time, 220 will be the 
 power of the jack. 
 
 JACK-SCREW. Figs. 2411, 2412, and 2413 represent a plan of a jack-screw for turning large stone, 
 used at the United States Dry Dock, Brooklyn. 
 
132 
 
 JACK, TRAVERSING SCREW. 
 
 ' .TACK, TRAVERSING SCREW. Figs. 2415 
 and 2416 exhibit a side view and plan of the 
 screw modification. The screw-jack A is bolted 
 to the plank C ; at the other end of the plank is 
 fixed the rack G, in which the toe of the strut F 
 advances as the screw B is elevated ; the strut 
 works in a joint in the follower K : the position 
 2417. 
 
 — { *L 
 
 ^ h 
 
 :d id 
 
 — - -j i\ 
 
 2416. 
 
 
 
 ©nnife 
 
 xpnTrm 1 i i 1 1 1 : u mm. 
 
 of the strut when the screw is 
 depressed is shown by the dotted 
 lines. The object of this strut 
 is to relieve the screw of the vio- 
 lent cross-strain to which the 
 apparatus is subject, when the 
 engine or carriage is pulled over 
 by the lever ; which strain is 
 entirely transferred to the strut, 
 and the screw has merely to 
 carry the load. 
 
 The operation of traversing 
 the jack is as follows : By hook- 
 ing the link I upon the hook of the lever E, the toe of the lever being inserted into a ratch of the rack 
 II of the lower plank, when a man bearing down the end of the lever, drags the apparatus and engine or 
 carriage towards him with great facility ; the same lever is used to turn the screw, and to produce the 
 traverse motion. 
 
 JACK, TRAVERSING. Another form of traversing jack is shown at fig. 2417, side elevation; fig. 
 2418 end elevation, and fig. 2419 section through vertical screw. 
 
 The lift of this jack is effected by means of a crank, or lever, applied to the axis a, which works tho 
 bevel-geer b c, the latter geer being cut on the projecting face of the nut c ; the revolution of this nut 
 lifts or lowers the vertical screw, and with it the jaw d ; the screw-head moving freely in a socket of the 
 jaw-head, permits the latter to rise or fall without side movement. 
 
 2418. 2419. 
 
 The horizontal screw a a , working into a nut in the foot of the upper screw-frame, effects the horizon- 
 tal or traversing movement of the jack, the frame of the lower screw serving as a bed or slide for the 
 latter movement. A ratchet-lever may he used to work either of the screws instead of a crank. 
 
 The Hydraulic Jack (Patent Portable Hydraulic Jack, R. Dudgeon, New York) is the simplest 
 
JACQUARD LOOM. 
 
 and most portable in comparison with the force it is capable of exerting. This jack, or press, appeart 
 to the eye, when depressed, a simple cylinder, and when elevated, to one cylinder sliding within another. 
 It is from two to eight or more inches in diameter, according to the power desired, with an enlarged 
 head (attached to the inner cylinder, which is the ram), having a socket for the reception of the lever, by 
 which the piston of the force pump is worked. 
 
 The ram, with its head, contains just so much water or other fluid as is required to fill the vacancy 
 in the cylinder, caused by the raising of the ram in the act of lifting; and when this is accomplished 
 the water is returned into its original recess by a valve operated by the lever that works the pump. The 
 force pump, piston and valves are contained inside of the ram. 
 
 The lever is detached, and may be put on at pleasure. The joints in the head maintain a parallel 
 motion for the force pump piston, which is the fulcrum of the lever. The ground-lifting attachment is 
 an iron tube screwed into the lower side of the head, and passing down to the bottom of the press out- 
 side of the cylinder, on the lower end of which is a claw that supports the weight to be raised. 
 
 These presses are light, portable, and of easy application. A press to raise four tons not weighing 
 more than 50 lbs., and one to raise 60 tons, not more than 200 lbs. They are all worked by the labor 
 of one man only, which is capable of raising ten tons through a space of one foot in one and a half min- 
 utes, or sixty tons the same distance in ten minutes. 
 
 JACQUARD. A peculiar and most ingenious mechanism, invented by M. Jacquart of Lyons, to be 
 adapted to looms for superseding the employment of draw-boys, in weaving figured goods. 
 
 Fig. 2420 is a front elevation of this mechanism, supposed to be let down. Fig. 2421 is a cross sec- 
 tion, shown in its highest position. Fig. 2422 the same section, but seen in its lower position. 
 
 A, is the fixed part of the frame, supposed to form a part of the ordinary loom ; there are two up- 
 rights of wood, with two cross-bars uniting them at their upper ends, and leaving an interval xy, be- 
 tween them, to place and work the movable frame B, vibrating round two fixed points a a, placed late- 
 rally opposite each other, in the middle of the space x y , fig. 2420. 
 
 C, is a piece of iron with a peculiar curvature, seen in front, fig. 2420, and in profile, figs. 2421 and 
 2422. It is fixed on one side upon the upper cross-bar of the frame B, and on the other, to the inter- 
 mediate cross-bar b, of the same frame, where it shows an inclined curvilinear space c, terminated below 
 by a semi-circle. 
 
 D, is a square wooden axis, movable upon itself round two iron pivots, fixed into its two ends ; which 
 axis occupies the bottom of the movable frame B. The four faces of this square axis are pierced with 
 three round, equal, truly-bored holes, arranged in a quincunx. The teeth a, fig. 2424, are stuck into 
 each face, and correspond to holes a, fig. 2427, made in the cards which constitute the endless chain for 
 the healds ; so that in the successive application of the cards to each face of the square axis, the holes 
 pierced in one card may always fall opposite to those pierced in the other. 
 
 The right-hand end of the square axis, of which a section is shown in double size, fig. 2423, carries 
 two square plates of sheet iron d, kept parallel to each other and a little apart by four spindles e, passed 
 opposite to the corners. This is a kind of lantern, in whose spindles the hooks of the levers ff \ turning 
 round fixed points g g', beyond the right hand upright A, catch hold, either above or below, at the plea- 
 sure of the weaver, according as he merely pulls or lets go the cord z, during the vibratory movement 
 of the frame B. 
 
 E, is a piece of wood shaped like a T, the stem of which, prolonged upwards, passes freely through 
 the cross-bar b, and through the upper cross-bar of the frame B, which serve as guides to it. The head 
 of the T piece being applied successively against the two spindles e, placed above in a horizontal position, 
 first by its weight, and then by the spiral spring h, acting from above downwards, keeps the square axis 
 in its position, while it permits it to turn upon itself in the two directions. The name press is given to 
 the assemblage of all the pieces which compose the movable frame B B. 
 
 F, is a cross-bar made to move in a vertical direction by means of the lever G, in the notches or 
 grooves i, formed within the fixed uprights A. 
 
 H, is a piece of bent iron, fixed by one of its ends with a nut and screw, upon the cross-bar F, out of 
 the vertical plane of the piece C. Its other end carries a friction roller J, which working in the curvi- 
 linear space c of the piece C, forces this, and consequently the frame B, to recede from the perpendicular 
 or to return to it, according as the cross bar F is in the top or bottom of its course, as shown in fio-s, 
 2421 and 2422. 
 
 I, cheeks of sheet iron attached on either side to the cross-bar F, which serves as a safe to a kind of 
 claw K, composed here of eight small metallic bars, seen in section figs. 2421 and 2422, and on a greater 
 scale in fig. 2424. 
 
 J, upright skewers of iron wire, whose tops, bent down hookwise, naturally place themselves over the 
 little bars R. The bottom of these spindles, likewise hooked in the same direction as the upper ones, 
 embraces small wooden bars l, whose office is to keep them in their respective places, and to prevent 
 them from twirling round, so that the uppermost hooks may be always directed towards the small metal- 
 lic bars upon which they impend. To these hooks from below are attached strings, which after having 
 crossed a fixed board, m n , pierced with corresponding holes for this purpose, proceed next to be attached 
 to the threads of the loops destined to lift the warp threads. K K, horizontal spindles or needles, ar- 
 ranged here in eight several rows, so that each spindle corresponds both horizontally and vertically to 
 each of the holes pierced in the four faces of the square axis D. There are therefore as many of these 
 spindles as there are holes in one of the faces of the square. 
 
 Fig. 2425 represents one of these horizontal spindles, n is an eyelet through which the correspond- 
 ing vertical skewer passes. o another elongated eyelet, through which a small fixed spindle passes tc 
 serve as a guide, but which does not hinder it from moving lengthwise, within the limits of the length 
 of the eyelet, p small spiral springs placed in each hole of the case q q, fig. 2424. They serve to bring 
 oack to its primitive position, every corresponding needle, as soon as it ceases to press upon it. 
 
13 1 
 
 JACQUARD LOOM. 
 
 Fig. 2426 represents the plan of the upper row of horizontal needles. Fig. 2427 is a fragment of tlx 
 endless chain, formed with perforated cards, which are made to circulate or travel by the rotation of the 
 shaft IX In this movement, each of the perforated cards, whose position, form and number, are deter- 
 mined hy the operation of tying-up of the warp, comes to be applied in succession against the four faces 
 of the square axis or drum, leaving open the corresponding holes, and covering those upon the face of 
 the axis, which have no corresponding holes upon the card. 
 
 Now let us suppose that the press B is let down into the vertical position shown in fig. 2422 ; then tli» 
 sard applied against the left face of the axis, leaves at rest or untouched the whole of the horizontal 
 spindles (skewers), whose ends correspond to these holes, but pushes back those which are opposite tc 
 the unpierced part of the card ; thereby the corresponding upright skewers, 3, 5, 6, and 8, for example. 
 
JACQUARD LOOM. 
 
 13A 
 
 pushed out of the perpendicular, unhook themselves from above the bars of the claw, and remain ir 
 their place, when this claw comes to be raised by means of the lever G ; and the skewers 1, 2, 4, and 
 7, which have remained hooked on, are raised along with the warp threads attached to them. Then by 
 the passage across of a shot of the color, as well as a shot of the common weft, and a stroke of the lay 
 after shedding the warp and lowering the press B, an element or point in the pattern is completed. 
 
 The following card, brought round by a quarter revolution of the axis, finds all the needles in their 
 first position, lifts another series of warp threads ; and thus in succession for all the other cards, which 
 compose a complete system of a figured pattern. 
 
 If some warp yarn should happen to break without the weaver observing them, or should he mistake 
 
 his colored shuttle yarns, which would so far disfigure the pattern, he must undo his work. For this 
 purpose, he makes use of the lower hooked lever f, whose purpose is to make the chain of the card go 
 backwards, while working the loom as usual, withdrawing at each stroke the shot both of the ground and 
 of the figure. The weaver is the more subject to make mistakes, as the figured side of the web is 
 downwards, and it is only with the aid of a bit of looking-glass that he takes a peep of his work from 
 time to time. The upper surface exhibits merely loose threads in different points, according as the 
 pattern requires them to lie upon the one side or the other. 
 
 Thus it must be evident, that such a number of paste-boards are to be provided and mounted as 
 equal the number of throws of the shuttle between the beginning and end of any figure or design which 
 is to be woven ; the piercing of each paste-board individually, will depend upon the arrangement of the 
 lifting rods, and their connection with the warp, which is according to the design and option of the 
 workman; great care must be taken that the holes come exactly opposite to the ends of the needles ; 
 for this purpose two large holes are made at the ends of the paste-boards, which fall upon conical points, 
 by which means they are made to register correctly. 
 
 It will be here seen, that, according to the length of the figure, so must be the number of paste- 
 boards, which may be readily displaced so as to remount and produce the figure in a few minutes, ox' 
 
 2426 2427 
 
 l 
 
 1 ° § o O go 0 c ° - « fo n<i o§o 0 °g °c, ” S c.<VSj*o°° 8 I 1 
 
 t 
 
 L 
 
 I CL o O C 0 D ° 0 ,°*0o °00 °o °°n Q ° 0 l° rP° °„ ° rt °°o V °!° 0 0° [f 
 
 }•'& o ^ 8^0 0°o°00?0 D rgo OOtfo O 0 <5* 00 °o 8 R 0 8 o°off i 
 
 O °° ° 5° 0> 0 0 OCP° 0 OOCO c 'Oce CC 00o 0 OO^O S . Q 
 o qoO ooe Ooooooo r .°,.ooo to 0 o co o 
 
 S ° o° o o °0 °o C° o 0 g © °o o w 00 0 °o° o°oo r 
 
 remove it, or replace it, or preserve the figure for future use. The machine, of course, will be under- 
 stood to consist of many sets of the lifting rods and needles, shown in the diagram, as will be perceived 
 by observing the disposition of the holes in the paste-board ; those holes, in order that they may be ac- 
 curately distributed, are to be pierced from a gauge, so that not the slightest variation shall take place. 
 
 To form these card-slips, an ingenious apparatus is employed, by which the proper steel punches re- 
 quired for the piercing of each distinct card, are placed in their relative situations preparatory to the 
 operation of piercing, and also by its means a card may be punched with any number of holes at one 
 operation. This disposition of the punches is effected by means of rods connected to cords disposed in 
 a frame, in the nature of a false simple, on which the pattern of the work is first read in. 
 
 These improved pierced cards, slips, or paste-boards, apply to a weaving apparatus, which is so ar- 
 ranged that a figure to be wrought can be extended to any distance along the loom, and by that means 
 the loom is rendered capable of producing broad figured works ; having the long lever G placed in such 
 a situation that it affords power to the foot of the weaver, and by this means enables him to draw the 
 heaviest morintures and figured works, without the assistance of a draw-boy. 
 
 The machinery for arranging the punches, consists of a frame with four upright standards and cross- 
 pieces, which contains a series of endless cords passing under a wooden roller at bottom, and over pul- 
 leys at the top. 
 
 Fig. 2428 represents a single endless cord 1 1, which is here shown in operation, and part of anothel 
 endless cord 2 2, shown stationary. There must be as many endless cords in this frame as needles in 
 the weaving-loom a is the wooden cylinder, revolving upon its axis at the lower part of the standard ; b i 
 
136 
 
 JACQUARD PERFORATING MACHINE. 
 
 the two pulleys of the pulley-frames above, over which the indivi- 
 dual endless cord passes ; c is a small transverse ring. To each of 
 these rings a weight is suspended by a single thread, for the purpose 
 of giving tension to the endless cord, d is a board resembling a com- 
 mon comber-bar, which is supported by the cross-bars of thestand- 
 ard frame, and is pierced with holes, in situation and number, cor- 
 responding with the perpendicular threads that pass through them ; 
 which board keeps the threads distinct from each other. 
 
 At e the endless cord passes through the eyes of wires resembling 
 needles, which are contained in a wooden box placed in front of the 
 machine, and shown in this figure in section only. These wires are 
 called the punch projectors ; they are guided and supported by hori- 
 zontal rods and vertical pins, the latter of which pass through loops 
 formed at the hinder part of the respective wires. At f are two 
 horizontal rods extending the whole width of the machine, for the 
 purpose of producing the cross in the cords ; g is a thick brass plate, 
 extending along in front of the machine, and lying close to the box 
 which holds the punch-projectors ; this plate g, shown also in section, 
 is called the punch-holder ; it contains the same number of apertures 
 as there are punch-projectors, and disposed so as to correspond with 
 each other. In each of these apertures there is a punch for the 
 purpose of piercing the cards, slips, or pasteboards with holes ; h is 
 a thick steel plate of the same sizeas h, and shown likewise in sec- 
 tion, corresponding also in its number of apertures, and their dispo- 
 sition, with the punch-projectors and the punch-holder. This plate 
 h , is called the punch-receiver. 
 
 The object of this machine is to transfer such of the punches as may be required for piercing any in- 
 dividual card from the punch-holder g, into the punch-receiver h ; when they will be properly situated, 
 and ready for piercing the individual card or slip, with such holes as have been read in upon the machine, 
 and are required for permitting the warp threads to be withdrawn in the loom, when this card is brought 
 against the ends of the needles. The process of transferring the patterns to the punches is thus effected. 
 
 The pattern is to be read in according to the ordinary mode, as in a false simple, upon the endless 
 cords below the rod f and passed under the revolving wooden cylinder a, to a sufficient height for a per- 
 son in front of the machine to reach conveniently. He there takes the upper threads of the pattern, 
 called the beard , and draws them forward so as to introduce a stick behind the cords thus advanced, as 
 shown by dots, for the purpose of keeping them separate from the cords which are not intended to he 
 operated upon. All the punch-projectors which are connected with the cords brought forward, will be 
 thus made to pass through the corresponding apertures of the punch-holder g, and by this means will 
 project the punches out of these apertures, into corresponding apertures of the punch receiver h. The 
 punches will now be properly arranged for piercing the required holes on a card. 
 
 Remove the punch-receivers from the front of the machine ; and having placed one of the slips of 
 card or pasteboard between the two folding plates of metal, completely pierced with holes corresponding 
 to the needles of the loom, lay the punch-receiver upon those perforated plates, to which it must be 
 made to fit by mortices and blocks, the cutting parts of the punches being downwards. Upon the back 
 of the punch-receiver is then to be placed a plate or block, studded with perpendicular pins correspond- 
 ing to the above described holes, into which the pins will fall. The plates and the blocks thus laid to- 
 gether, are to be placed under a press, by which means the pins of the block will be made to pass 
 through the aperture of the punch-receiver ; and wherever the punch has been deposited in the receiver 
 by the above process, the said punches will be forced through the slip of pasteboard, and pierced with 
 such holes as are required for producing the figured design in the loom. 
 
 Each card being thus pierced, the punch-receiver is returned to its place in front of the machine, and 
 all the punches forced back again into the apertures of the punch-holder as at first. The next set of 
 cords is now drawn forward by ths next beard, as above described, which sends ont the punch-projectors 
 as before, and disposes the punches in the punch-receiver, ready for the operation of piercing the next 
 card. The process being thus repeated, the whole pattern is, by a number of operations, transferred to 
 the punches, and afterwards to the cards or slips, as above described. See Loom. 
 
 JACQUARD PERFORATING MACHINE. Machine for perforating metal plates, such as are used 
 for steam-boilers, &c. ; and employed for punching the plates of the tubular bridge at Conway, made at 
 the Globe Works, Manchester, by Messrs Roberts, Fothergibl & Co. 
 
 Fig. 2420 represents a sectional elevation of the machine; Fig. 2421 an elevation of the back of the 
 machine; Fig. 2422 a plan view of the apparatus for putting the punches out of action without stopping 
 the fly-wheel ; and Fig. 2423 a plan view of a few of the jacquard plates. Fig. 242G represents a front 
 elevation ; Fig. 2427 a side elevation ; and Fig. 2428 a horizontal section, taken through the dotted lines 
 A 'A 1 , in Figs. 2426 and 2427. Fig. 2429 is a detached view of the traverse apparatus, and Fig. 2430 
 a detached view of the holding-down or stripping apparatus. A A the standards. B the bed, through 
 which there is an opening for the punchings, or metal punched out of the plate, to fall through ; tliis bed 
 is inserted into the standards. C a stretcher-bar, to connect the top of the standards. D, fulcrum of the 
 levers q q which withdraw the punches, and of the lever w which traverses the plate. E a fulcrum shaft, 
 to which the levers jj and hlc are keyed. F the main or eccentric shaft, working in bushes in the 
 standards. G a spur-wheel, keyed on the eccentric-shaft. 1 1 a pinion, working into the wheel G. I the 
 fly-wheel shaft, on which are the fast and loose pulleys K and L, the pinion H, and the fly-wheel J. 
 M M connecting-rods, fitted to the eccentric necks of the shaft F. N N caps of the connecting-rods M M 
 
JACQUARD PERFORATING MACHINE. 
 
 137 
 
 2420. 
 
 0 0 guide-plates for the punch-rams P P. Q the cam-shaft, R a spur-wheel, loose on the cam-snail 
 and having on one side two projections, between which there is an opening. R* a locking-disk or plate 
 
138 
 
 JACQUARD PERFORATING MACHINE. 
 
JACQUARD PERFORATING MACHINE. 
 
 139 
 
 keyed on the shaft Q, having upon it a spring-catch 38, which takes into the opening between the pro 
 jectious on the wheel R. R and R* are seen detached in Fig. 2425, 24 25 2 : the dotted lines on R* repre- 
 sent a weight to counterbalance the levers k. S a toothed-wheel, keyed on the main-shaft F. T the 
 punch-ram depressor, secured to the connecting-rods M M by knuckle-joints at the lower end of the 
 connecting-rods. U a slide-bar, on which the frame traverses which carries the plate to be punched. 
 V V two short slide-bars, to carry one side of the traverse-frame. W a block of iron, fastened with 
 short wedges to the bed B to carry the die-plate X, into which the dies d are inserted, and prevented 
 from rising by a collar at the lower end of each, as seen ir Fig. 2430. Y a square shaft, carrying the 
 holding-down levers or stripping-fingers oo Z Z levers on each end of the shaft Y. a a the punches let 
 into the punch-holders b b bolted to the rams P, as seen in the detached view, Fig. 2424. c c pieces 
 bolted to the bed B to carry the adjusting slide-bars V Y. d dies inserted into the holder X. ee, Fig 
 2420, are the selecting slide-bars, which, when allowed to pass through the card-plate, enter the card 
 roller/, without being pushed backwards by them; the card-roller has in this case six sides, and the 
 belt of jacquard-plates, after passing over it in the usual manner, passes over a round roller suspended 
 in a swing-frame, at such an angle as shall keep the belt moderately tight, whilst the roller/ advances 
 towards and recedes from the selectors e. r/g brackets projecting from the depressor T, and carried up 
 and down with it. h h sliding-blocks, in which the journals of the card-roller turn. To an upright cast 
 on each of these blocks, is fitted a rod of round iron, thus *, with a flat foot, long enough to extend over 
 two of the six pins in the ends of the card-roller, against which the flat foot of the rods is made to press, 
 by spiral-springs coiled around them in the usual manner employed in the jacquard-loom, which is gen- 
 erally known, and need not be further described, ii, Fig. 2420, are two sets of guide-blocks, for the 
 selectors e, one on each side of the depressor, adjustable laterally by set-screws on flat bars, extending 
 across the machine ; the use of these blocks is to carry the selecting-bars e, which are round at the end 
 that enters the cards, and flat at the other end, to keep them in their proper positions ; the centre por- 
 tion of each selecting-bar is a solid piece of iron, projecting as much below the round stem as will, when 
 the selecting-bar is driven backwards by a card-plate, permit the depressor T to complete its downward 
 stroke without the selecting-bar touching the ram P under it. jj are levers keyed on the shaft E, and 
 connected at their lower end by links to the slide-blocks h h. k k are levers also keyed on the shaft E 
 and having each a friction-roller at its lower extremity. On the shaft Q are two cams, one of which 
 works a lever k on one side of the shaft, and the other cam works the other lever k on the opposite 
 side. One of the cams, through the medium of the levers jj, and the links before referred to, causes the 
 roller/ to approach the selecting-bars e, and the other cam causes the roller to recede from them, until, 
 by a catch employed in the ordinary way in the jacquard-looms, the roller / is made to turn through 
 one-sixth of a revolution, and is then retained in that position by the pressure of the spiral-spring 
 and flat foot above referred to. 1 1 are brackets attached to the depressor T at the back of the ma- 
 chine. m a bar resting on the brackets 1 1, and connected by rods with the sliding-blocks h h, which, 
 on receding, cause the bar m to bring all the selecting-bars e into the position for depressing the rams, 
 as seen in Fig. 2430. tin are levers having their fulcra on studs screwed into the standards; one 
 end of these levers is connected by a rod p with the levers Z Z ; the other end is furnished with a 
 roller which is acted upon by a cam u on the shaft Q. oo are the holding-down levers, adjustable 
 laterally on the shaft Y, so as to admit of one of them being placed on each side of every punch. 
 pp are rods connecting the levers n and Z. By adjusting the length of these rods, the levers oo 
 
 are made to press upon plates of different thicknesses, so as to hold the plates down while the 
 
 punches are being withdrawn, q q levers turning on the fulcrum-bar D for withdrawing the punches 
 by means of the cams r r that actuate levers q q. sa broad but rather thin bar, extending through 
 the series of punch-rams P, shown by dotted lines. The punch-rams P are made with slots, through 
 which the bar s passes, and these slots must be about two inches longer than the width of the bar s, 
 in order to allow the punch-rams to be forced down when the bar is at the bottom of its stroke. 
 1 1 are links connecting the bar s with the levers q q. uu are cams which depress the holding- 
 down levers oo, through the medium of the levers n n, rods pp, and levers ZZ, and hold down the 
 plate while the punches are being withdrawn, v a cam for the traversing-rack 5. w a lever 
 turning on the fulcrum-bar D, and worked by the cam v. x the cam for lifting the rack 5. y a lever 
 
 turning on a stud in the standard, and worked by the cam x for lifting the traversing-rack 5. z a rod 
 
 connecting the lever y with the lever 8. 1 is a lever on the traverse-shaft 2 ; 3 another lever on 
 
 the shaft 2. 4 a link connecting the lever 3 with the rack 5. 6 a rod connecting the lever w with 
 
 the lever 1 for traversing the rack 5. 7 a shaft for carrying the levers 8, 9, and 10. 11a link con- 
 necting the levers 10 and 12. 13 a shaft carrying the levers 12 and 14. 15 and 16 are links con- 
 necting the rack 5 with the levers 9 and 14. 17 the upper or retaining rack. 18 a stud carrying t lie 
 
 elbow-lover 19, which is provided with a handle. 20 another stud carrying the elbow-lever 21, which 
 is connected by a link 22 with the lever 19. The rack 17 is carried on studs in the horizontal arm of the 
 levers 19 and 21. 23 division-studs in the bar 24 of the traversing-frame. 
 
 The plate to be punched is put into a traversing-frame formed of two side-bars 24 and 25, and two 
 stretcher-bars secured by cottars to the side-bars, which are rabbeted to support the plate, and, when 
 required, furnished with clamps to hold the plate down. 24 represents one of the sides of the trav- 
 ersing-frame, in which there is a groove to fit on the slide-bar U ; into the outer side of the bar 24 is 
 screwed a series of studs 23, represented in the engravings as being 12 inches from centre to centre 
 apart from each other. The side 25 of the frame slides on the bars V Y. When the plates to be 
 punched are very long, rollers may be used to carry the projecting ends of the traversing-frame. In 
 Fig. 2428 is shown part of a frame, with a plate partly perforated. The racks 5 and 17, Fig. 2429, are 
 drawn with three teeth in the length of a foot, which will divide plates to a four-inch pitch ; but it will 
 be obvious, that for a different pitch the racks must be changed, and it may in some cases, (such as 
 when the pitch required is not an aliquot part of a foot,) be necessary to alter the distance between the 
 studs 23. Fig. 2429 represents the traverse apparatus, in the position it will be in when the retaining 
 
1 40 
 
 JACQUARD PERFORATING MACHINE. 
 
JACQUARD PERFORATING MACHINE. 
 
 141 
 
 2427. 
 
 G 
 
1412 
 
 JAPANNING. 
 
 rack is down, and the punches in the act of passing through the plate, and the traversing-rack having 
 completed its return-stroke. 
 
 When the punches are being raised, the traversing-rack will rise also; and by the side-piece 26 
 (which is attached to it) acting against the roller 27, on a stud in the rack 17, will raise it also, and set 
 the frame at liberty to be advanced by the cam x, through the mechanical means already described 
 In Fig. 2420 this traverse apparatus is shown in the position it assumes when the plate is advancing 
 The spiral-spring 28 acts on the lever 21, and forces the rack 17 down on to the pins 23. For every 
 hole required to be punched in line with the width of the plate under operation, a corresponding 
 hole must be made in a plate of the jacquard, and an additional hole, marked 30, is also made, int« 
 which the stopping-bar 31 enters at every stroke until the punching be completed, at which time 
 the jacquard-plate 32, which is left blank, will push all the selecting-bars e beyond the rams P, and at 
 the same time, by pushing the bar 31, disengage the cam-shaft Q, by the mechanism to be hereafter 
 explained, at the point where the punches and the levers o are held up, and thus will allow the perfo- 
 rated plate to be taken out of the machine, and another plate to be put into it. The stopping-bar 31 is 
 provided with a projection on its lower surface, which depresses the click-lever 39 when the bar is 
 pushed back; the lever 33 is keyed on a shaft 34, moving in bearings at the back of the depressor; on 
 the other end of the shaft 34 is keyed the lever 35, to the upper end of which is attached the link 36, 
 connecting it with the elbow-lever 37 ; the end of the other arm of this lever is inclined, for the purpose 
 of unlocking the plate R* and is provided with a stud, on which is a latch 38, the tail of which comes 
 m contact with the incline on the elbow-lever 37, when it is in the position shown in dotted lines in Fig. 
 2422 ; and as the wheel R revolves, the latch becomes disengaged from the opening between the two 
 projections cast on the said wheel, at which time the cam-shaft Q ceases to revolve. When the stopping- 
 bar 31 has been pushed back, it depresses the lever 39, and liberates the lever 33 from behind the 
 projection on the lever 39, when the spring 40 will pull the elbow-lever 37 into the position shown 
 in dotted lines. To the blocks h a small shaft is attached, on which are two levers, suspending by 
 links a plate of metal similar to a blank card-plate, except that the holes for the guide-pifas are cut at 
 the bottom edge. At each end of the same shaft is a lever-handle, held up or down by a side-spring in 
 the ordinary way. The use of this apparatus is as follows ; Should it be required to stop the machine 
 before the plate is finished, by raising the lever here referred to, the blank plate will come in front ot 
 the roller, and will act the part of a blank jacquard-plate, and stop the machine. 
 
 Flaving now described the principal parts of the machine, we shall proceed to explain the manner of 
 its working. The plate to be punched having been placed in the traversing-frame, on the sides U and 
 V, is then pushed forward. In its progress, the first pin of the series 23 passes under the inclined end 
 of the rack 17, until the first notch in the rack falls upon the pin. The driving-strap being now on the 
 fast pulley K, the machine is set to work by pulling down the handle 42, keyed on the shaft 34, until 
 the lever 33 is latched by the click-lever 39 ; the elbow-lever 37 is then, by the spiral-spring 40, brought 
 into the position shown in Fig. 2422. The latch 38 being now liberated, will, by the action of the spring 
 41, Fig. 2420, drop into the notch in the wheel R the first time it comes round ; the cam-shaft Q wall 
 now revolve at the same speed as the shaft F, and the jacquard-roller/ will be drawn back and made 
 to perform l-6th of a revolution on its centres, after which it will be advanced, and the first card of the 
 series will remove those selecting-bars for which there are no holes in the jacquard-plate ; the other 
 selecting-bars will remain over their respective rams P, which will then force down the punches through 
 the plate, by the descent of the depressor T. A little before the punches have gone through the plate 
 under operation, the levers o are made to press upon it, and are held there while the punches are 
 being withdrawn by the bar s, which rises simultaneously with the depressor T, during one-half of its 
 ascent. 
 
 Whilst the depressor is continuing its assent and descent through the other half of the stroke, the 
 roller /'recedes, and draws with it the bar in, which brings all the selectors again over the punch-rams 
 P. The roller f while receding, having performed another sixth of a revolution, will, on advancing, 
 bring another of the jacquard-plates against the selectors, and the operation will be repeated until all 
 the holes are punched in the plate under operation. 
 
 JAPANNING. The art of covering paper, wood, or metal with a thick coat of a hard, brilliant 
 varnish : it originated in Japan, whence articles so prepared were first brought to Europe. The material, 
 if of wood or papier-machee, is first sized, polished, and varnished ; it is then colored or painted in 
 various devices, and afteiwards covered with a highly transparent varnish, or lacquer, which is ulti- 
 mately dried at a high temperature, and carefully polished. 
 
 An improved method of performing the above-mentioned operation is thus described by the inventor : 
 
 The articles which are to be so coated, or covered, or ornamented, may be made of wrought-iron, or 
 of other malleable metal or metals, which will withstand a strong red-heat without injury, such as brass 
 or copper, the making of such articles being performed by any of the usual modes of cutting out of 
 laminated or sheet metal, and hammering, or stamping, or otherwise forming to the required shape for 
 any intended article, by aid of all or any of the various modes of cutting out of laminated sheet metal 
 practised by the makers of articles of malleable metals, except that the more fusible metals which will 
 not withstand a strong red-heat, such as tin, lead, zinc, pewter, or Britannia metal, are not fit to be used 
 for making such articles or any part thereof, and, therefore, tinning and soldering with soft solder is not 
 applicable for taking such coating, or for uniting together the parts of the said articles ; but in case of 
 an article which cannot conveniently be formed of one piece of metal, (and which is to be preferred,) 
 then the several pieces or parts must be united or strengthened by all or any of the well-known 
 methods of overlapping, turning down the edges, wiring, creasing, and hammering down, or by riveting 
 or dove-tailing, as may be most suitable for the article ; and in case of soldering being resorted to, it 
 must be hard soldering with brass or spelter, usually termed brazing, and by any or all the means 
 aforesaid the articles are to be made of wrought-iron, or of other malleable metal or metals, and in the 
 same manner as if they were intended to be japanned, painted, varnished, lacquered, or tinned. When 
 
JAPANNING. 
 
 143 
 
 made, the articles are to be subjected to a full red-heat, by placing them in an annealing oven or fur 
 nace, -which may be of the same kind as is commonly used for annealing articles of stamped metal, ot 
 for annealing metal for being stamped ; a number of articles of the same shape and size being piled up 
 one upon another in such furnace in order that they may the better keep their fcrm, and sand may be 
 interposed between the articles so piled up for that purpose. Small articles may be heated in a muffle, 
 such as hereafter described, into which flame does not enter, and after having been kept to a full red- 
 heat for about half an hour, the articles are either withdrawn from the oven or furnace and allowed to 
 cool, or else the oven, or furnace, or muffle, with the articles therein, may be allowed to cool, and the 
 articles removed. By the said heating, all liquid or greasy matter will have been dissipated, and the 
 surfaces of the articles will have been oxidated, and then all oxide or scale is to be removed from the 
 surfaces of the articles by rubbing them with sandstone, for the plain and accessible parts, and with 
 worn-out tiles, scrapers, or other suitable tools, for the less accessible places. Or articles of such a 
 truly circular or elliptical form as to admit of being turned in a lathe, may be mounted in a chuck 
 and turned ; a broad flat tool being presented to every part of the revolving surface in succession, 
 leaving the surface of the metal smooth and even, without the necessity of its being quite bright or 
 polished. The articles being thus rendered perfectly clean, are ready to receive the first coat or covering 
 of partially vitrifiable material, (the composition whereof is hereafter described,) and which is applied 
 to the surface of the articles in a semi-liquid state, which state results from the materials having been 
 ground very fine when in mixture with water, and to the consistence of a thick cream, and then strained 
 through fine lawn. A suitable quantity of such semi-liquid is poured out from a ladle or spoon upon 
 the surface of the article whilst it is held over a large vessel containing such semi-liquid, and by holding 
 the article in the hands with the surface inclined, the semi-liquid runs slowly and gradually along the 
 surface, so as to spread itself out and cover the same, the article being turned about and inclined in 
 different directions in succession, in order to cause the semi-liquid to run over the surface until the 
 whole is completely covered and with a coating of uniform thickness, all surplus of such semi-liquid 
 being allowed to drain off therefrom into the basin or other vessel beneath. Great care must be taken, 
 however, to avoid air-bubbles, specks, or defective places in the coating, and which is only accomplished 
 by using precaution in the previous preparation of the semi-liquid, or by thoroughly grinding or straining 
 it, in order to keep it free from lumps and from any coarse particles, and afterwards avoiding all violent 
 stirring or splashing, so as by no means to get air intermixed with it, but using only a gentle motion 
 when taking it up with a ladle or spoon ; and such a quantity only of the semi-liquid at one time as is 
 not materially greater than sufficient for covering the surface of the article to be coated. The operation 
 of coating will be greatly facilitated by performing the same in a warm room, and by making the article 
 rather warmer than the semi-liquid itself, but not so as to feel hot to the hand; and such warmth of the 
 room and of the article will dispose the covering, after it has been spread over the surface of the article 
 as aforesaid, to begin to dry upon that surface, and, in a short time, so far as not to run or move thereon, 
 after which the drying is to be completed by placing the article in an ordinary japanner’s stove, which 
 should be kept heated to a temperature of about 180° Fahrenheit, the article being left therein until all 
 moisture is gradually dried away, or so as to leave a dry whitish covering, which adheres sufficiently to 
 the surface of the article for keeping its place thereon, but which would, nevertheless, be easily rubbed 
 off if handled roughly, or if only touched rudely by the fingers. The composition of materials found 
 to be the most suitable for the first coating may be prepared as follows : — 
 
 Take six parts (by weight) of flint-glass, -broken into small fragments, three parts of the ordinary 
 borax of commerce, one part of red-lead, and one part of oxide of tin. These four ingredients being 
 brought into the state of a coarse powder, are to be well mixed together, by pounding them in an iron 
 mortar, and then the mixture is to be fritted in the same manner as is usually done with the materials 
 for making glass, or by subjecting such mixture to a strong red-heat in a reverberatory furnace for three 
 or four hours or more, it being frequently stirred and turned over to expose every part to the flame, and 
 to more effectually mix the ingredients, as well as to expel all volatile matter ; and towards the latter 
 part of the time the heat must be increased, until a partial melting or semi-vitrification has commenced, 
 when the whole is to be withdrawn from the furnace in a pasty state, and let fall into water in order to 
 be suddenly cooled, whereby it becomes cracked, so as to be afterwards easily broken into small frag- 
 ments, or into a coarse description of powder, which is called fritt, and which is for the first body or 
 coat, but which fritt is only one of the ingredients in the composition of such first coat. With one part 
 (by weight) of the fritt described is to be mixed two parts of calcined bone, ground to powder; and the 
 mixture of fritt and bone is then to be ground with water in a mill, called a porcelain-mill, such as is 
 used for grinding the materials for making porcelain ; and which operates by trituration of the materials 
 with water between chert-stones, or other hard silicious stones, whereof some are fixed at the bottom of 
 a tub or vessel containing water, having the materials mixed therewith ; and other such stones rest by 
 their own weight upon the said fixed stones, and are carried round thereon with a circular motion, com- 
 municated by the moving part of the mill, so as to rub over the fixed stones and grind the materials 
 between them, which operation is continued until the materials are reduced to a state of extremely 
 minute division in the water, forming therewith the semi-liquid (of about the consistence of cream) 
 already alluded to, and which is ready for use so soon as it has been passed through appropriate sieves, 
 so as to effectually separate any particles that have escaped the operation of grinding. 
 
 In articles requiring only one side to be coated, such as the hollow side of a kettle, or pot, or jug, or 
 such as a mug, or plate, or dish, or waiter, or tray, or basin, or cup, or bread-basket, or cheese-tray, (to 
 all which, as well as to numerous similar articles, this invention is considered as being particularly ap- 
 plicable,) such hollow side may be first coated with vitrified materials after the manner already 
 explained ; after which, the outside may be coated or covered by any of the ordinary methods of 
 japanning ; and in applying such first coating of semi-liquid to the hollow surface or side of such articles 
 as those stated, it is observed that, instead of pouring out a auantity thereon, as in other cases, the 
 vessel may be filled, or if both sides have to be coated, may be wholly immersed, and in the act of 
 
144 
 
 JAPANNING. 
 
 draining off the surplus the fingers of the two hands should be applied to the edges only cf the article, 
 and at the two opposite sides of its circumference, so that the weight of such article will balance itself 
 and render it easy to turn it over and about, so as to drain in succession from either side, extreme care 
 being requisite in all such cases to insure a uniformity of surface. When the coating is so far dried that 
 it will not run, the article is to be laid down upon the points of three small supports, made of burnt 
 earthenware, and which are made to stand upon a small iron plate that serves to carry away the article 
 which is next introduced into the japanner’s stove, where it is dried more effectually. When the article 
 is afterwards removed from the said stove, in order to be introduced into the muffle for the firing or 
 burning in of the coating, (and in the manner hereafter described,) it is still to be borne upon the same 
 three supports, the iron plate on which they rest being removed from the stove, and also introduced 
 into the mufHe, or with the three supports and the article upon it ; and in case of any specks or deficient 
 places appearing in the coating, such places may be mended by applying a portion of the semi-liquid 
 thereto by aid of a brush, and in the manner of painting or pencilling, and then returning the article to 
 the stove, and drying the same, so that every part shall not only be completely covered, but also effect- 
 ually dried on, and before it goes into the muffle, the ultimate appearance of the article depending very 
 materially upon the manner of conducting this first part of the process, and upon the care with which 
 the coating has been applied, and, upon the proper grinding and mixing of the materials, uniformity o( 
 surface in the first process being considered absolutely indispensable, in order to insure the successful 
 result of such after-processes as have yet to be detailed. The firing next described is for the purpose 
 of so far vitrifying the materials and hardening the coating as to fasten it on to the surface of the 
 articles, and is performed in a furnace, of the kind used by painters in enamel, being an oven strongly 
 heated by fire applied beneath it, and by the flame therefrom passing in flues around it, and may be 
 called a muffle ; but no fire, or flame, or smoke can enter into the interior where the articles are placed. 
 The articles are left in the muffle, and subjected to the heat until such time as the earthy composition 
 will have undergone so much of the commencement of fusion or partial vitrification as to render the 
 particles of the coating firmly adherent one to the other, and also to the surface of the metal articles, 
 and which are then to be withdrawn and laid on a flat iron bench to cool. When cold, such parts of 
 the surface as have been coated will be found to present the dead whitish appearance of earthenware, 
 which has been once fired only, but has not been glazed, being in that state which by potters is termed 
 “ biscuit.” The time that the articles should remain in the heated muffle will vary from a few minutes 
 to half an hour, depending upon the size and number of the articles, and upon the heat of the muffle ; 
 neither can such time be stated with precision, but the operator, it is observed, will soon find out what 
 length of time is most suitable for any particular description of article, and also what heat should be 
 kept up in order to obtain the required result, by observing, so soon as the article shall have become 
 cool, whether the coating has been rendered sufficiently hard, and has or has not become firmly ad- 
 herent. When cool, the newly formed coating is to be wetted, either by passing over it a sponge that 
 has been dipped in water, or else by dipping the article itself, and a second coating is then applied over 
 the first coat and dried thereon in the japanner’s stove, and then fired in the muffle in the same manner 
 as the first, only the composition is to be different; and the patentee goes on to state that the compo- 
 sition he lias found to be the most suitable for such second coating is as follows : Take 32 parts (by 
 weight) of calcined bone, ground to a fine powder, 16 parts of china-clay, and 14 parts of Cornwall 
 stone in fine powder, and 8 parts of carbonate of potash ; the latter being dissolved in water, the other 
 ingredients are mixed up therewith, so as to make a thick paste, which is then fritted for two or three 
 hours in a reverberatory furnace, until it assumes the appearance of biscuit-china, which is to be reduced 
 to powder; then -5^- parts (by weight) of such powder are to be mixed with 16 parts of flint-glass 
 broken small, 5-J- parts of calcined bone ground, and 3 parts of calcined flint ground, the said mixture 
 being afterwards ground with water in a porcelain-mill until it is reduced to a semi-liquid state about 
 the consistence of cream, and which has to be carefully strained, as before, through sieves of lawn, when 
 it will be ready for use in the same manner as already explained in reference to the composition or 
 semi-liquid employed for the first coating. In firing the second coating care must be taken that the 
 articles are kept long enough in the muffle, and that the heat is sufficient for thoroughly incorporating 
 the second coat with the first, also for thoroughly hardening both coats. After firing for the second 
 coat, the article, when cool, will have a stronger and whiter color, and a more decided resemblance to 
 articles of good earthenware, but still only in the state called “ biscuit,” 
 
 The articles having been twice coated with composition as described, and twice fired, so as to assume 
 at this stage the external appearance of a good earthenware biscuit, the patentee further states, that 
 should it be desired to produce a very white color, so as to resemble the very finest earthenware or 
 porcelain, then in lieu of the 16 pounds of flint-glass, mentioned as forming part of the last composition, 
 proper for the second coating, he prefers to substitute a like quantity of the composition prepared as 
 follows: Take four parts (by weight) of feldspar in powder, four parts of white sand, four parts of car- 
 bonate of potash, one part of arsenic, six parts of borax, one part of oxide of tin, one part of nitre, and 
 one part of whitir.g; the mixture of these materials is to be fritted either in a reverberatory furnaca 
 (as was before described for the materials of the first coating,) or otherwise such fritting may be pc? 
 formed in a crucible strongly heated in a furnace, the heat in either case being continued until tire 
 materials are partially fused, and the appearance when cold will be that of a whitish enamel, which 
 being reduced to powder, such powder is to be substituted, weight for weight, in place of the 16 pounds 
 or parts of flint-glass formerly mentioned as part of the composition of materials for the second coating, 
 all the other materials remaining the same. Excepting only for the purpose of obtaining whiteness of 
 color, the flint-glass is in other respects described as being cheaper, and yet equally good. After the 
 articles have received the second coating, (of either of the compositions described,) and have been fired 
 and then cooled, they are to be wetted with a sponge, or by dipping them into water, as was done after 
 the first coating, and are then ready for receiving the third coat or glaze, which is also applied in a 
 semi-liquid state, great care being required in draining off the surplus semi-liquid glaze, so as to leave 
 
JOINT, CLASP-COUPLING. 
 
 145 
 
 only a thin coating or covering, equally distributed over every part of the second coating of partially 
 vitrified material, in order that the article, after being again exposed to the heat of the muffle, and 
 afterwards withdrawn, may present the appearance of glazed earthenware of good quality, and which 
 will not otherwise be the case ; whereas, with appropriate care, and when the composition specially 
 adapted for producing whiteness has been employed, it will resemble earthenware, it is stated, of the 
 very best quality. The composition found to be the most suitable for the third coat, or glaze, is as 
 follows: Take twelve parts (by weight) of feldspar, in powder, four and a half parts of china-clay, 
 eighteen parts of borax, three parts of nitre, one and a half parts of carbonate of potash, and one and a 
 half parts of oxide of tin, which materials being well mixed together, the mixture is to be fritted either 
 in a crucible or in a reverberatory furnace, and then the frit being reduced to powder, is to be ground 
 with water in a porcelain-mill to a semi-liquid state, and strained through fine lawn in the same manner 
 as described for preparing the composition for the first coat. Or, instead of the above composition, the 
 following may be adopted for such third coat or glaze : Take nine parts (by weight) of feldspar, in 
 powder, two parts of china-clay, nine parts of borax, two parts of nitre, three parts of carbonate of soda, 
 and one-quarter part of arsenic ; which materials being mixed together the mixture is to be fritted, and 
 then reduced to powder, ground in water, and strained as aforesaid. In firing the articles in the muffle 
 for the third coat or glaze, the heat of the muffle, and the time the articles are subjected to such heat, 
 must be sufficient to cause the glaze to become thoroughly vitrified, and to spread over the surface of 
 the second coat so as to become incorporated with that coat, and effectually glaze the surface thereof, 
 as in earthenware of excellent quality; and in case there are any imperfections in the glaze after it has 
 been so fired, then, after the articles are cold, another coating of the same glaze may be applied in a 
 semi-liquid state and dried in the japanner’s stove, and then fired in the muffle as was done for the first 
 coating of glaze ; and so in like manner a third coating or glaze may be applied and fired, if found 
 requisite. 
 
 JOINT, CLASP-COUPLINQ— West & Thompson’s. 
 are two flanges joined each to one of the pieces of 
 pipe. It will be observed that the coupling parts of 
 these flanges are bevelled, and have no bolt-holes, as 
 those in common use all have. C is a piece of vulcan- 
 ized India-rubber, or any other packing that may be 
 thought necessary, although a pressure can be exerted 
 in bringing the flanges so close together that the joint 
 is made perfectly tight without any packing, but we 
 think that it is all the better to use a little packing. 
 
 B B is the clasp. This is divided into two parts, and 
 this part is represented with the flange resting on it. | 
 
 By placing the concave part over the bevel of the 
 flanges, and securing the two parts of the clasp to- 
 gether by bolts passing through E E, is all the opera- 
 tion that is required in connecting two separate pieces 
 of pipe together. Every mechanic will perceive that 
 the tighter the clasp is screwed up, the faces of the 
 flanges are brought closer together, and the joint is 
 thereby made exceedingly tight. Experience has pro- 
 ven this joint to be excellent for pipes that are used 
 for conducting steam. 
 
 It will be clearly seen that this improved coupling is applicable to vessels and other articles of 
 angular or curved forms, and that whatever may be the form, any desired and effective mode of draw- 
 ing or forcing together the segments of the ground clamp may be substituted for screw-bolts or the 
 conical rings. 
 
 DD, Fig. 2431, are two pieces of pipe; A A 
 
 In coupling angular vessels, or other articles, it will be found to be advantageous to make the grooved 
 clamp in as many sections as there are sides to the figure, and for round couplings it will be found suffi- 
 cient to make it in two parts for all articles of moderate size ; but when the diameter is very considerable 
 it may be divided into three or more parts. 
 
 This improved mode of coupling is equally applicable to the securing of nozzles, stop-cocks, bonnets, 
 and many other articles not necessary to enumerate, and particularly to cylinder-heads, in which the 
 edge of the head takes the place of one of the flanges. 
 
 It will be evident to any engineer or machinist, from the foregoing, that shafts and other solid bodies 
 can be coupled together in the same manner as hollow conduits or vessels, and with equal advantage, 
 and by a similar arrangement of parts, and therefore it is deemed unnecessary to give an example. 
 
 The flanges, instead of solid projections of the bodies to be united, may be made separate, and 
 connected therewith in any manner desired, as the mode of making the flanges forms no part of the 
 invention. 1 
 
 The leading advantages of this mode of coupling over the ordinary double flange and bolts heretofore 
 and now generally used, are, a great reduction in the number of screw-bolts used, which occupy much 
 time in connecting and disconnecting joints, particularly in the parts of steam-engines, such as cylinder- 
 heads, and other parts, which require to be frequently connected and disconnected for packing and other 
 purposes, and increased strength and more perfect and continuous support, as the flanges by the im- 
 proved plan, instead of being reduced in strength by the numerous bolt-holes, are pressed together aud 
 supported all round by the grooved segmental clamp, and the strain on the threads of the screw-bolts, 
 instead of being in the line of the force which tends to separate the coupling, as in the old plan, is nearly 
 at a right angle therewith, and therefore greatly relieved. There are other advantages which, however 
 it will be unnecessary to enumerate. 
 
 Vol. II. — 10 
 
146 
 
 JOINTS, AND JOINING TIMBERS. 
 
 JOINT, PATENT EXPANSION. Figs. 2432 and 2433 represent a patent expansion-joint, patented 
 by Z. R. Dunham, of New York, March 20, 1847. 
 
 2433. 
 
 JOINTS, AND JOINING TIMBERS. As timber cannot always be obtained of sufficient length 
 for tie-beams, or bridges, it is necessary to unite two or more pieces together by their ends, which is 
 called scarfing, and is differently performed by carpenters. The most common means is lapping, or 
 halving, or, as it is sometimes called, ship-lapping. This is nothing more than 
 cutting away a part of the thickness of one piece, and an equal quantity of the , 
 other which is to be joined to it, so as to suffer the diminished end of one piece j 
 to overlap that of the other, (as in Fig. 2434,) and then uniting them by nails L 
 or wooden pins, which are called tree-nails. This method is applied to plates, 
 bond timbers, and others, where there is not much longitudinal compression or extension ; where this 
 kind of effect is to be provided for, the upper as well as the lower timbers should be cut and let into 
 each other ; the under piece having a tenon formed at its extreme end, with a corresponding cutting to 
 receive it in the upper piece. That these tenons may be enabled to pass each other, it is necessary to 
 cut away a part of the timbers in the middle of the length of the joint, equal to the length of the two 
 tenons, so as to form a square hole, through the middle of the timbers to be joined together, and this is 
 afterwards closed up by driving an oak key into it ; this also helps to drive the tenons to their respect 
 ive mortises, and prevents the timbers from being pulled asunder. The thickness of the key, in ordei 
 that it may not be compressed, should be equal to a third of that of the piece into which it is inserted 
 Another principle is here shown, which is more simple, the joint being cut obliquely ; to make these 
 two pieces stiff, the ends of both should be cut in an angular form. To strengthen these scarfs, iron 
 straps and screw-bolts are added ; but no joining can be made so strong as the timber itself. 
 
 In making joints, it must be remembered that all timber is liable to shrink when dry, and when wet 
 to expand ; on this account, dovetail joints should be avoided as much as possible, as they are liable to 
 draw out ; and all joints should be made with reference to their contraction and expansion, which some- 
 times tends to split off portions of the framing. Where iron bolts or straps are introduced, care must 
 be taken that their effect is not lost by the changes that the timber undergoes. The areas of the for- 
 mer should never be less than two-tenths of the area of the section of the beam ; it must also be recol- 
 lected in making a joint, that when force is applied to any portion, the fibres of the timber will slide 
 upon each other. 
 
 Fishing a beam is merely placing a piece of the same scantling to one side of the timber to be united, 
 and bolting them or hooping them together. Separate pieces of timber are united either by scarfing, 
 Botching, cogging, pinning, wedging, tenoning, Ac. 
 
 Scarfing consists in cutting away equally from the ends, but on the opposite sides, of two pieces of 
 
 2434. 
 
 BZH 
 
JOINTS, AND JOINING TIMBERS. 
 
 147 
 
 timber for the purpose of connecting them lengthwise. The usual method of scarfing bond and wall 
 plates is by cutting about three-fifths through each piece, on the upper face of the one and the under 
 face of the other, about 6 or 8 inches from the end transversely, making what is termed a kerf; and 
 longitudinally from' the end, from two-fifths down, on the same side, so that the pieces lap together like 
 a half dovetail. Fig. 2435 is a scarf. 
 
 Notching is either square or dovetailed, and is made use of for connecting the ends of wall-plates and 
 bond-timbers at the angles, in letting joists down on girders, binders, purlins, or principal rafters. 
 
 Cogging, or cocking, is a species of notch extending on one side, and having a narrow cog alone in 
 the bearing piece, flush with its upper face. It is principally made use of in tailing joists on wall- 
 plates. 
 
 Pinning consists in inserting cylindrical pieces of wood or iron through a tenon. 
 
 Wedging is the insertion of triangular prisms, whose converging sides are under an extremely acute 
 angle, into or by the end of a tenon, to make it fill the mortise so completely as to prevent its being 
 withdrawn. 
 
 Tenon and mortise of the most simple kind is shown in Fig. 2439, in which the two timbers united 
 are at right angles with each other. The tenon is on that which appears horizontal, while the mortise 
 is cut in the upright timber. The tenon is left one-third of the thickness of the timber, as shown in the 
 upper part of the figure. 
 
 The greatest strain upon the fibres of a girder is at the upper and lower parts, decreasing gradually 
 towards the middle of the depth, which is the best situation to make the mortise. The form to be given 
 to the tenon requires consideration. Some carpenters introduce it at the lowest part of the girder, 
 which in a great degree destroys its stiffness : being a sixth of the depth, it should be placed at one- 
 third of the depth from the lowest side. Horizontal timbers, intended to bear great weights, should be 
 always notched on their supports, in preference to being framed in between them ; and this rule is 
 applicable to inclined timbers, as common rafters and braces. All the pressures to which they are 
 subjected should be brought to act in the direction of their lengths, and the form of the joint should be 
 such as to convey the pressure as much as possible into the axes of the timber. When subjected to a 
 strain, a partial bearing is liable to very serious disadvantages, particularly in bridges. 
 
 2441. 
 
 "LT 
 
 I 
 
 2439. 2440. 
 
 Where the mortise is to be made in the upright timber, and the tenon to be cut on another inclined, 
 as in a brace to a partition, a bevelled shoulder, Fig. 2441, is cut on the inclined piece, and a sinking 
 made in the upright post to receive it — the pin which secures it in its mortise passing through the 
 tenon. 
 
 The bevelled shoulder adds greatly to the strength of a mortise and tenon joint, and should never be 
 dispensed with : it renders the junction of the two pieces of timber more exact, and makes the abut- 
 ments of all the fibres stronger and more capable of resistance. 
 
 The common method of effecting such a junction does not occupy so much time or labor, but is not 
 so effective : it is usual to drive one or two wooden pins through holes bored for the purpose at right 
 angles through the timber in which the mortise is made, as well as through that which has the tenon. 
 
 Boring the hole for the pin requires to be nicely performed, in order that it may draw the tenon tight 
 into the mortise prepared to receive it, and make the shoulder-butt close into the joint, without running 
 the risk of tearing out a portion of the tenon beyond the pin. Square holes and square pins are pre- 
 ferred to round, as they bring more of the wood into action, and there is less liability to split. 
 
 Foxtail wedging, adopted by ship-carpenters, is made with long wooden bolts, which do not pass 
 completely through the timbers, but take a very fast hold : they are subject to be crippled in drawing 
 if they are too nicely fitted : this is remedied by placing a thin wedge into the hole previous to the 
 
148 
 
 JOINTS, AND JOINING TIMBERS. 
 
 insertion of the wooden bolt, which, when driven, is split by the wedge, and thus squeezed tight to the 
 sides of the hole. 
 
 Bond-timbers and wall-plates require to be carefully notched together at every angle and return, and 
 scarfed at every longitudinal joint. 
 
 2443. 
 
 To make a good tie-joint requires great attention on the part of the carpenter ; and, for uniting wall- 
 plates, the. dovetail joint, Fig. 2444, is sometimes adopted. If the effects that 0444 
 
 shrinking may produce be taken into consideration, the more usual system of 1 ’ , 
 
 halving, Fig. 2443, is decidedly preferable. Whenever this joint is employed, j /(S J 
 
 a stout pin of tough oak, or an iron bolt, should be driven through to render it ' — I 
 
 secure ; and, where there is the slightest tendency for one piece to slide from the other, iron straps 
 must he used. 
 
 Timbers which are laid upon the plates, and intended to act as ties, should be cut with a dovetail and 
 let into the timber it is to secure. Generally, where they cross at right angles, halving or cutting away 
 the moiety of each is adopted, and one is let into the channel cut in the other. 
 
 For joining two pieces of timber together, notching is the most common and simple method ; for, 
 when four angles are to be formed, the surfaces of one piece are both parallel and perpendicular to 
 those of the other. A notch may be cut out of one piece (Fig. 2444) the breadth of the other, which 
 may be let down on the first ; or the two pieces may be both notched to each other, and then secured 
 by an oak pin : this is the best practice when each of the timbers is equally exposed to a strain in any 
 direction. When one piece has to support the other transversely, the upper may have a notch cut 
 across it, to the breadth of two-thirds the thickness of the one below, which must also have a similar 
 notch cut out on each upper edge, leaving two thirds of the breadth of the middle entire, by which 
 means the strength of the supporting or lower piece is less diminished than if a notch of less depth 
 were cut the whole breadth. Such joints are particularly adapted for purlins, when let down upon the 
 principal rafters. 
 
 Lapping is performed in a variety of ways — either by simply halving the end of each timber, or by 
 halving and dovetailing, as in Fig. 2445. I'n the latter case, the tim- 
 bers act as a tie, and cannot be readily pulled asunder. 
 
 In these joints the greatest attention is required to make the sev- 
 eral parts abut completely on each other, as the least play or liability 
 to motion at once destroys their efficacy. The butting joints, being 
 slightly tapered to one side of the beam, require very moderate blows 
 with a hammer to force them into their place : if driven too hard, the 
 parts will be liable to strain, and the abutments to split off. It is better, sometimes, to leave the abut 
 ments open, and afterwards drive in a small wedge, which, if made of hard wood and not likely to 
 
 
 
 compress, is an excellent substitute. Iron has been said to injure the fibres of the timber, from its toe 
 great hardness ; otherwise it is well adapted for the joggles and wedges. 
 
 Two pieces of timber may be united in such a manner that they preserve the same breadth and 
 depth throughout, which is of great importance in the construction of beams 
 for bridges or roofs of considerable span. The length to be given to the 
 scarf must depend upon the force that will cause' the fibres of the timber to 
 slide upon each other ; and that for oak, ash, or elm should be six times 
 the depth of the timber ; in fir, twelve times : but where bolts are used so 
 much is not required in either case. The simplest method for uniting the r 
 ends of two timbers is by cutting away an equal portion of each, and letting L 
 one down upon the other. Fig. 2449. 
 
 Timbers united together by a number of such cuttings, afterwards united and bolted through or 
 hooped round with iron, aro capable of sustaining great resistance : a stirrup-iron at each end 
 
 2449. 
 
JOINTS, AND JOINING TIMBERS. 
 
 14& 
 
 holds the timbers in their places, and one or more bolts are sufficient to prevent their being draws 
 asunder. 
 
 The carpenter frequently exercises great ingenuity in joining timbers of considerable scantling, Fig 
 2450 ; and, by the introduction of iron or small cubes of harder 
 wood into the joints, can prevent their being thrust or drawn 
 out of their position either longitudinally or laterally. 
 
 The scarfing of girders and beams have a great variety of 
 forms given them, and are sometimes bolted through, at others 
 strapped round with strong hoops of iron, Figs. 2449 to 2454. 
 
 Where bolts are dispensed with, it is perfectly clear that the 
 joint cannot have half the strength of an entire piece. Where 
 the stress is longitudinal, two irons put on each side will pre- 
 vent the scarf that is merely indented from pulling asunder ; but such a provision will not maintain 
 the constant horizontal position of the timber. 
 
 When a scarf is forced to its bearings by the introduction of keys or wedges driven tight, they some- 
 times receive an additional strain, and it is often found advisable to omit them, and to bring the joint? 
 
 2452. 
 
 to a bearing by some other means before the bolts are inserted. When keys are made use of, they 
 should be of very hard wood, having a curled grain, which resists the insertion of the fibres opposed 
 to it. 
 
 To prevent lateral movement cogging is adopted, in addition to the ordinary method, and a small 
 tenon or cog is left upon a portion of the scarf, which enters into a notch prepared in the piece which is 
 to eover it, as shown in Figs. 2448 to 2452. Beams intended to resist cross-strains require to be lengthened 
 more frequently than any others, and, from the nature of the strain, a different form of scarf must be 
 made use of from that which is required for a strain in the direction of its length. When timber is 
 subjected to both strains, the cross-strain is that which demands the greatest attention. Where a floor 
 is supported, the scarfing requires to be further secured by iron bolts, made to pass through a longi- 
 tudinal piece laid to cover the under side of the joint. 
 
 Bearing-posts, when used to support the floors of a magazine or warehouse, are generally formed 
 exactly square. Some timber will support, while that of another quality will suspend, the most ; 
 therefore, in the selection of story-posts, we must pay attention to these peculiarities. Iron, however, 
 is generally used for these purposes, in consequence of its horizontal sectional area occupying less space 
 than timber of the same strength. 
 
 When a tie-beam is mortised through to receive a king or queen post, and it is necessary to provide 
 for the means of holding it up, the tenon should not be pinned through, as it is not advisabl^to depend 
 entirely on the pins for the support : the tenon should be cut like a half dovetail, or in a sloping direc- 
 tion on one side, and left straight on the other : the mortise-hole should be so cut that the lower end can 
 juot pass. When it is in its place, a wooden key or wedge is driven tightly on the straight side, which 
 forces the tenon against one side of the mortise-hole, and prevents it effectually from being drawn out : 
 oak or iron may be added, or an iron strap may be applied. 
 
 Tenons may be wedged at the end ; but to do this they must be made long enough to pass entirely 
 
 2450. 
 
 through the mortise : two saw-cuts are then made across it, and the wedges are driven home. The 
 tenon sometimes splits, but not sufficiently to injure its strength. When in machinery it is not practi- 
 cable to cut the mortise through, the fox-tail wedging is adopted : the tenon is made to fit the mortise 
 
150 
 
 JOINTS.. AND JOINING TIMBERS. 
 
 exactly, the wedges are loosely put into the saw-cuts, as before, and the whole is driven to its place. 
 When the wedges touch the bottom of the mortise, they cause it to spread, and thus hold the tenon 
 firmly in its place. 
 
 Dovetailing in some degree resembles mortising and tenoning, and is more adapted to uniting 
 together the angles of framework. The feet of the rafters require the mortise and tenon to be care- 
 fully made, and the thrust is destroyed to a certain extent to obtain greater strength. A portion of 
 the rafter is tenoned into the tie-beam, and another small part is let into the upper part of it : both 
 rafter and tenon are cut at right angles with the inclination of the roof. In Fig. 2455, the rafter has 
 two bearing shoulders in its depth, one behind the other, in addition to the tenon which unites them. 
 Struts and braces which are loaded require but little mortising to keep them from sliding out of their 
 places : the more flat their ends can be cut, the more efficient will they be. The shrinking of timbers 
 sometimes occasions them to become loose, particularly where there is not much stress upon them. 
 
 King-posts, queens, and principal rafters, which are subject to great strains, should have iron straps 
 or ties when they unite with the tie-beam, as in Figs. 2456 and 2457 ; and an iron strap should embrace 
 
 2457. 
 
 the head of the kings and queens, and unite with the principal rafters, the feet of which, in large build- 
 ings, sometimes have their abutment in a cast-iron shoe, which prevents the splitting off the end of the 
 tie-beam. 
 
 The ends of king or queen posts may have a screw-bolt passed into them, which allows the nut to be 
 turned at pleasure ; and thus the framing may be tightened again when shrinking of the timbers ren- 
 ders it necessary. This, in many instances, is preferable to the iron strap, and keys or screws put in 
 the ordinary way. 
 
 Whatever form we adopt for the butting-joint, we must be careful that all parts bear alike ; for, in 
 the general compression, the greater surfaces will be less affected and the smaller undergo the greatest 
 change. When all have come to their bearing, they should exhibit an equally close joint ; and as large 
 timbers are moved with some difficulty, the joint cannot be often put to the test of trying whether it 
 fits nicely : it must, therefore, be set out with great precision, and worked, with regard to its lines, with 
 exactness. A very small portion of a tie-beam left at the end is sufficient to withstand the horizontal 
 thrust of a principal rafter, and blocks may be used at the ends where the rafters abut to give additional 
 strength. 
 
 Scarfing a timber in a perpendicular direction. — When the top surface is divided into nine squares, if 
 four are cut down, the other five serve as tenons to enter into as many vacant spaces left in the piece 
 of timber placed upon it, as seen in Fig. 2458 ; or two may be cut away, as in the same figure, to re- 
 ceive a tenon left on the upper piece. 
 
 2453. 
 
 2459. 
 
 Partitions and framing for the outside of buildings , &c., Fig. 2459, are a species of timber walls, 
 usually covered with lath and plaster, and formed of upright posts, mortised into a head and sill, 
 braced in different directions, and filled in with quarters. The posts are placed at the extremities, as 
 well as at the sides of all doors and openings. When a partition dividing two or more rooms has a 
 bearing which is perfectly solid throughout, it is better without braces : the posts or quarters have 
 only then to be maintained in an upright position, which is effected by driving pieces between them 
 horizontally, so as to strut them, and prevent their bending. Where they rest upon joists, which are 
 liable to shrink, and yield to a weight placed upon them, the partition should be trussed in a manner 
 to throw its load on the parts able to sustain it. In most houses we find great neglect upon this sub- 
 ject, wliich occasions cracking in the cornice, inability to open and shut the doors, and many other incon- 
 veniences. 
 
 The thickness given to partitions which do not exceed 20 feet in length, is 4 inches. The posts are 
 then 4 inches square, and the other timbers 4 by 3. When they are of greater extent, they should be 
 lucrcased in thickness. When it is required to make a doorway in the middle, the truss may be formed 
 
JOINTS, AND JOINING TIMBERS. 
 
 151 
 
 by the braces, tlie inclination of which should be at an angle of about 40° with the horizon. When the 
 doors are at the sides, the truss may be formed over the heads. The posts should all be strapped tc 
 the truss, and the braces halved into the upright posts. 
 
 The weight of a square of quartered partition may be estimated at from 12 cwt. to 18 cwt., and every 
 precaution should be taken to discharge its weight from the floor on which it is placed, to the walls, 
 which are its best points of support. In ancient timber houses, mills, Ac., the fronts or external sides 
 are formed of upright posts, placed at a distance equal to their scantling : these are mortised and ten- 
 oned into a top and bottom plate, which serves also to carry the floors. The posts at the angles are of 
 a larger scantling ; and into these, which form openings for doors and windows, are framed horizontal 
 pieces, which serve for heads and sills. Braces are then introduced, crossing each other, like a St. 
 Andrew’s cross. Above the lintholes, and beneath the sills, short quarters or punchions fill in the 
 space, and the whole are mortised, tenoned, and pinned together. The framing should be placed on 
 brickwork, or a wall of masonry, so as to be kept quite clear of the ground. 
 
 Floors. — When the bearings are equal, if joists of the same width, but of different depths or thick- 
 nesses, are used, their strength is increased in proportion to the squares of their vertical thickness : 
 when the joists are but 6 inches deep, they are in strength to those of 8 inches in depth, as 36 to 64 — 
 the square of 6 being 36, and that of 8, 64. The quantity of timber in the one case to that of the 
 other is as 4 to 3 — so that one-third more timber gives a strength double that of the other. 
 
 Where square oak joists are used, and the bearing 1'2 feet, their scantlings should be 6 inches, and 
 laid at a similar distance apart. Such a floor contains the same quantity of timber as if entirely formed 
 of 3-inch plank : the strength of timber being as the square of its vertical thickness, it results that the 
 strength in these two instances is as 2 to 1 : the floor composed of 3-inch plank is only half the strength 
 of the other ; but had the whole been formed 6 inches thick, instead of with joists 6 inches apart, it 
 would have been 4 times as strong — the square of 3 being 9, and the square of 6, 36. 
 
 Naked floors are divided into single-joisted, double, and framed floors : and it must be remarked that 
 unsawn timbers are considerably stronger than planks or scantlings cut out of a round tree. When a 
 tree is cut longitudinally, and formed into two pieces, these will support less than they would do when 
 united in the original tree, arising from the circular concentric rings which compose the tree being cut 
 through, which renders the timber more compressible on one side than on the other ; and as the texture 
 is less close where it has been sawn, it is also more susceptible of change from humidity on alternation 
 of temperature. 
 
 Joists whose width is less than half their vertical thickness, are subject to twist and bend if not 
 strutted ; and for this reason squared timber was usually employed by the builders in the middle ages ; 
 and we have numerous examples four or five hundred years old, where the timber selected has the pith 
 in the centre, and the concentric rings nearly entire, being in a sound and perfect condition. Experience 
 also teaches us that timber, whether sawn or unsawn, used for a floor of 16 feet bearing, composed of 
 12 joists, 8 inches square, placed at a distance of a foot apart, is much stronger than another of 24 
 joists, 8 by 4, placed edgeways, at a distance of 6 inches apart, although there is the same quantity of 
 timber in both cases. 
 
 Single-joisted floors consist of one series of joists, which ought to be let down or halved on to wall- 
 plates of a sufficient strength and scantling to form a tie, as well as a support to the floors. Each joist 
 should be spiked or pinned to the timbers on which it lies. Wherever fireplaces occur, and the joists 
 cannot get a bearing on the wall, they are let into a trimmer or piece of timber framed into the two 
 nearest joists that have a bearing: into this the other joists are mortised. As the trimming joists sup- 
 port a greater weight, they must be made stronger than the others, and should have an eighth of ar. 
 inch additional thickness given to them for every joist they carry. When the bearing exceeds 8 or 9 
 feet the joists should be strutted, or they will have an inclination to turn sideways : the joists in use. 
 being generally thin and deep, require strutting on all occasions, and a rod of iron is often passed 
 through them, which, being screwed up after the strutting-pieces are placed, gives the entire floor great 
 solidity and firmness. The weight of a square of single-joisted floor varies from 10 cwt. to 1 ton, and 
 the joists should never extend to a greater bearing than 20 feet in ordinary cases. 
 
 2460. Mortises and Tenons. 
 
 To find the depth of a joist, when the length of bearing and breadth in inches is given : divide the 
 square of the length in feet between the supports by the breadth of the joist in inches, and the cube 
 root of the quotient, multiplied by 2'2 for fir and 2'3 for oak, gives the depth in inches. A single-joisted 
 floor which has the same quantity of timber as a double floor, is considerably stronger, particularly if 
 properly strutted, than the latter. The plates, bedded on the walls, upon which the joists are to be 
 tailed down, should have their depth equal to half that of the joists, and their width half as much 
 more. In many instances the plates are not bedded entirely in the wall, but have one-half resting 
 beyond the face on corbels let into the wall, at a distance of 6 feet apart. To form the entaille ot 
 dovetail, great care should be used, to prevent the joist from drawing out of its place when once 
 pinned down. 
 
152 
 
 KILN. 
 
 Double floors are formed of joists, binders, and ceiling-joists. The binders rest upon the plate* 
 bedded on the walls, and serve the purpose of supports to the joists which are bridged on them, as well 
 us to the ceiling-joists, which are pulleys mortised into their sides. When the depth of a binding-joist 
 is required, the length and breadth being given, divide the square of the length in feet by the breadth 
 in inches, and the cube root of the quotient, multiplied by 342 for fir, and 3'53 for oak, will give the 
 depth in inches. When the length and depth are given, and the breadth is required, divide the square 
 of the length in feet by the cube of the depth in inches, and multiply the quotient by 40 for fir, and 44 
 for oak, which will give the breadth. The above rules suppose the binders to be placed at a distance 
 of 6 feet from each other. 
 
 Binding-joists (Fig. 2461) must be framed into the girders, and care must be taken that the bearing 
 parts fit the mortise made for them very accurately : the tenon should be one-sixth of the depth, and 
 placed at one-third of the depth, measured from the lower side. When binding-joists only are employed 
 to carry the ceiling, their scantlings may be found in the same manner as those of ceiling-joists, which 
 are small timbers, and only, of a sufficient thickness to nail the laths to. When their length and bearing 
 are given, their depth may be found by dividing the length in feet by the cube root of the breadth in 
 inches, and multiplying the quotient by 0 64 for fir, or 0'67 for oak, which will give their depth in 
 inches. Ceiling-joists are usually notched to the under sides of the binding-joists, and nailed to them : 
 this is better than mortising, which weakens the binder, and gives more labor. 
 
 KALEIDOSCOPE. This instrument, the invention of Dr. Brewster, in its most common form con- 
 sists of a tin tube, containing two reflecting surfaces, inclined to each other at any angle which is an 
 aliquot part of 360°. The reflecting surfaces may be two plates of glass, plain or quicksilvered, or two 
 metallic surfaces, from which the light suffers total reflection. The inclination of the reflector that is in 
 general most pleasing is 18°, 20°, 22-J- 0 , or the twentieth, eighteenth, and sixteenth part of a circle ; but 
 the planes may be set at any required angle, either by a metallic, a paper, or cloth joint, or any other 
 simple contrivance. When the two planes are put together, with their straightest and smoothest edge 
 in contact, they will have the form of a book opened at one side. When the instrument is thus con- 
 structed, it may be covered up either with paper or leather, or placed in a cylindrical or any other tube, 
 so that the triangular aperture may be left completely open, and also a small aperture at the opposite 
 extremity of the tube. If the eye be placed at the aperture, it will perceive a brilliant circle of light, 
 divided into as many sectors as the number of times that the angle of the reflectors is contained in 
 360°. If this angle be 18°, the number of sectors will be 20 ; and whatever be the form of the aper- 
 ture, the luminous space seen through the instrument will be a figure produced by the arrangement of 
 twenty of these apertures round the joint as a centre, in consequence of the successive reflections be- 
 tween the polished surfaces. Hence it follows that if any object, however ugly or irregular in itself, be 
 placed before the aperture, the part of it that can be seen through the aperture will be seen also in 
 e^erv sector, and every image of the object will coalesce into a form mathematically symmetrical, and 
 highly pleasing to the eye. 
 
 The eye-glass placed immediately against the end of the mirrors, as well as another glass similarly 
 situated at the other end, is of common transparent glass. The tube is continued a little beyond this 
 second glass, and at its termination is closed by a ground glass, which can be put on and off. In the 
 vacant space thus formed, beads, pieces of colored glass, and other small bright objects are put. The 
 changes produced in their position by turning the tube give rise to the different figures. 
 
 KEDGE. A small anchor used to keep a ship steady and clear from her bower anchor while she 
 rides in a harbor or river. They are generally furnished with an iron stock, which is easily displaced 
 for the convenience of stowing. 
 
 KEEL. The principal piece of timber in a ship, which is usually first laid on the blocks in building. 
 It supports and unites the whole fabric — since the stem and stern posts, which are elevated on its 
 ends, are, in some measure, a continuation of the keel, and serve to connect and enclose the extremities 
 of the sides by transoms, as the keel forms and unites the bottom by timbers. 
 
 False-lceel is a strong, thick piece of timber bolted to the bottom of the keel, which is very useful in 
 preserving its lower side. In large ships of war the false keel is composed of two pieces, called the 
 upper and lower false keels. 
 
 Keel is also a name given to a low, flat-bottomed vessel, used in the river Tyne to bring the coals 
 down from Newcastle for loading the colliers : hence a collier is said to carry so many keels. 
 
 KEELSON. A piece of timber forming the interior of the keel, being laid upon the middle of the 
 floor-timbers immediately over the keel, and serving to bind and unite the former to the latter by 
 means of long bolts driven from without, and clinched on the upper side of the keelson. 
 
 KILN. A structure or machine designed for drying substances by the application of heat. Their 
 forms are as various as the substances or manufactures for which they are designed ; for, although it 
 may be said that a certain kiln will answer several purposes, yet for one single purpose we often find a 
 variety of kilns employed. The requisite qualities in a good kiln are cheapness and durability of con- 
 struction, effectiveness in producing the required result with the utmost economy of fuel, a perfect com- 
 mand of the temperature, and facility of working. Ovens must be regarded as of the same class ot 
 apparatus as kilns : indeed, the terms kiln and oven are often indiscriminately applied to the same 
 structure, as may be noticed under several articles in this work. Under the head of Lime the usual 
 for m of lime-kilns is described ; and under Coal and Iron, several forms of coke-ovens. In this place 
 we shall notice a combination of both, which was the subject of a patent granted to Mr. Charles 
 Heathoru about seven years ago, since which time it has been in successful operation. 
 
 Heo.th.orrC s patent combination of a lime-kiln with a coke-oven . — The object of this invention, as ex- 
 pressed in the specification of the patent, is the preparation of quick-lime and coke in the same kiln at 
 one operation. The economy of tins process must be evkWt from the circumstance, that the infiamma- 
 
KILN. 
 
 153 
 
 ble part of the coal which is separated to form it into coke, is the only fuel employed to burn the lime , 
 and as the coke is in many places as valuable as the coal from which it is prepared, the cost, if any, ol 
 making lime, must be reduced to the most trifling amount. Fig. 2462 presents a vertical section of the 
 lime-shaft and coke-ovens : a a are the side walls, 4 feet thick, of a rectangular tower, the internal 
 space being filled with limestone from the top to the iron bars b b at bottom, whereon the whole column 
 rests. The limestone is raised in a box d, or other proper receptacle, to the top of the building, by 
 means of a jib and crane e , or other tackle, which is fixed at the back of the tower, together with a 
 platform projecting beyond the walls for affording security and convenience for “ landing” the limestone 
 when raised as represented, the jib is swung round, and the lime-box tilted, by which the whole con- 
 tents are thrown down the shaft. The coke-ovens, of which there may be two, or a greater or lesse 
 
 number, according to the magnitude of the works, are constructed and arranged in connection with tne 
 lime-shaft in the same manner as the two represented in the diagram a iff These ovens are supplied 
 with coal through iron doors in the front wall, (not seen in the section ;) the doors have a long and nar- 
 row horizontal opening in the upper part of them to admit sufficient atmospheric air to cause the com- 
 bustion of the bituminous or inflammable part of the coal ; the flames proceeding from thence pass into 
 the lime-shaft through a series of lateral flues, (two of which are brought into view at g g,) and the draught 
 is prevented from deranging the process in the opposite oven by the interposition of the partition wall 
 h , which directs the course of the heat and flames throughout the whole mass of the lime, the lower- 
 most and principal portion of which attains a white heat, the upper a red heat, and the intervening 
 portions the intermediate gradations of temperature. When the kiln is completely charged with lime, 
 the openings in front and beneath the iron bars at i i are closed and barricaded by bricks and an iron- 
 cased door, which is internally filled with sand to effectually exclude the air, and prevent the loss of 
 heat by radiation. Therefore, when the kiln is at work, no atmospheric air is admitted but through th« 
 narrow apertures before mentioned in the coke-oven doors. When the calcination of the lime is com- 
 
154 
 
 KILN. 
 
 pleted, the barricades at i i are removed, the iron bars at b b are drawn out, by which the hme fall* 
 down and is taken out by barrows. It sometimes happens, however, that the lime does not readily fall 
 having caked or arched itself over the area that encloses it, in which case a hooked iron rod is em- 
 ployed to bring it down. To facilitate this operation in every part of the shaft where it may be neces- 
 sary, a series of five or six apertures, closed by iron doors, is made at convenient distances from the 
 top to near the bottom of the shaft : two of these are brought into view at k k. Two similar apertures 
 are shown in section in the coke ovens at b b, which are for the convenience of stoking and clearing out 
 the lateral flues g g from any matter that might obstruct the free passage of the heated air. When the 
 coals have been reduced to coke, the oven doors in front (not shown) are opened, and the coke taken 
 out by a peel iron, the long handle of which is supported upon a swinging jib that acts as a movable 
 fulcrum to the lever or handle of the peel, and facilitates the labor of taking out the contents of the 
 oven. The operation of this kiln is continuous, the lime being taken from the bottom whenever it is 
 sufficiently burned, and fresh additions of raw limestone being constantly made at the top. 
 
 Kilns for drying corn . — If air and moisture be carefully excluded from grain, it may be kept unin- 
 jured for an indefinite length of time. This is proved by an extraordinary experiment made with some 
 Indian corn found in the graves of the ancient Peruvians, buried more than 300 years ago. Some of 
 this corn being sown, it vegetated and came to maturity. We believe a similar fact is recorded respect- 
 ing some grain found in the ruins of Herculaneum. But to preserve corn, even for a short period, it 
 should be perfectly dry when housed, and carefully protected from dampness. But it not unffequently 
 happens, during a wet harvest season, that the corn is necessarily carried from the field in a damp state ; 
 and as few farmers have the means of properly and speedily drying it, large quantities are irrecoverably 
 spoiled after all the labor and cost of production. The method of drying on the perforated floor of a 
 kiln (which is usually resorted to where it can be obtained) is a very tedious, defective, and expensive 
 mode, and is attended with great labor, owing to the grain requiring to be continually turned over and 
 spread by a workman, whose utmost care is insufficient to cause every part to receive an equal degree 
 of heat. It therefore becomes a matter of considerable importance to devise a simple, efficacious, and 
 economical method of drying grain under these circumstances ; and we think Mr. Jones’s apparatus for 
 this purpose, shown in the following figures, is well adapted to the end proposed. Fig. 2463 is a ver- 
 tical section of the apparatus, which is formed of two iron cylinders a b , placed one within the other, 
 
 each being closed at the upper and lower end by two concentric cones, C D. The annular space be- 
 tween the cylinders, as also between the cones, is an inch and a quarter in width, for the reception of 
 the grain, to be dried by its passing through the machine : both the internal and external bodies are 
 perforated throughout with about 2300 holes to the square foot. The kiln is supported on five cast-iron 
 columns, or legs, three of which are shown in the section as at E : these are attached to a strong iron 
 ring which surrounds the base of the cylinder. From the heads of these columns descend, along the 
 sides of the cone, five long bolts, as at G-, which are passed through the same number of legs in the 
 cast-iron ring surrounding the neck of the lower cone. From this ring proceed five stays, as at I, which 
 are fastened to the middle of the columns by a nut on each side. The body is sustained, “both exter- 
 nally and internally, by iron hoops, as at K, and the distance between the cylinders is preserved by a 
 number of short stays. In the front of the kiln a passage is cut out, as at 0, in which is fixed the fire- 
 place, through which are passages for the heated air to pass into the cylinder. These passages, as well 
 as the flues, which proceed circuitously from the fire to the chimney, are best shown in the horizontal 
 
KILN. 
 
 15 < 
 
 section, Fig. 2464. And in the vertical section of the detached fireplace, Fig. 2465, Q is the fire-hole, 
 
 S the ash-hole, T the fire-bars, and U the chimney, which passes up nearly in the middle of the kiln. 
 The wheat is admitted into the kiln from above through a hopper, and through the tube W, and, falling 
 upon the apex of the cone, is distributed equally on all sides between the cylinders, the little asperities 
 in which not only slightly retard the descent of the grain, but likewise impart to the particles a con- 
 stant, slow, rolling motion, whereby every individual grain is exposed to the same degree of tempera- 
 ture ; the grain from thence converges into the lower cone, and ultimately escapes through the spout at 
 bottom into sacks, or on to the ground, as may be required. The passage of the grain through the 
 machine may be either accelerated or retarded, according to its peculiar condition, by enlarging or con- 
 tracting the aperture through which it is discharged. The moisture is carried off by evaporation 
 through the perforations of the plates, with great rapidity. The kilns 
 may, of course, be made of any dimensions. One of 6 feet internal di- 
 ameter, and 12 feet in length, between the apexes of the upper and lower 
 cones, has been said to be capable of perfectly drying more than 100 
 quarters of wheat in 24 hours. 
 
 In Fig. 2466 is shown a contrivance for drying grain which lias been 
 noticed in several French papers, and announced as having been success- 
 fully adopted in one of the departments. The apparatus consists of a 
 long spiral tube a a like a distiller’s worm, reaching from the basement to 
 the upper floor and through the roof of the granary, which forms a passage 
 for the heated air from a close stove below. Externally round this tube 
 is placed another tube b b, winding, like the interior one, in a spiral direc- 
 tion, and at about an inch and a half from it. This external tube receives 
 the corn from above, through a hopper c, and it is punched throughout 
 with numerous small holes, through which the vapor escapes, as it is 
 formed by the damp corn coming in contact with the inclosed heated chim- 
 ney. The corn, in consequence, becomes thoroughly dried before being 
 discharged at the bottom, and that without the intervention of any manual 
 labor. 
 
 Hebert’s patent kiln was devised for drying washed grain ; but as this 
 kiln is equally applicable to the drying of malt, seeds, and all other 
 matters of a similar kind and form, and by a mode that is as novel as it 
 is efficacious, we give a description of it in this place. In the following 
 engravings, Fig. 2467 exhibits a longitudinal section of the apparatus, 
 and Fig. 2468 a transverse section of a long air-trough, shown at e in Fig. 
 
 2467. At a is shown one of a series of five or six common iron gas- 
 tubes, placed side by side, and curved in the form represented to consti- 
 tute a fireplace ; the space between the tubes serving for the admission 
 of air for combustion, which enters through the ash-pit door b at the 
 side, provided with an air regulator : the fireplace is inclosed in front, 
 at c, by a common door and frame. The heated air, and other products 
 of combustion from the fuel, pass along the flue d to the funnel or chim- 
 ney. The bottom and two sides of the flue d are of brick, but the top is 
 of iron, being formed of the bottom of a long, shallow iron box, or air- 
 trough, e ; this box has no cover but one of extremely open-wove canvas, 
 which forms a part of an endless cloth or band fff, that is continually 
 made to travel lengthwise over the whole area of the said trough — the 
 edges of the cloth gliding between grooves and over tie-rods, (shown in 
 the cross section, Fig. 2468, where the dotted line f indicates the endless 
 cloth,) that prevent the cloth from sagging. This cloth is made to travel 
 by the revolution of three rollers or drums ej h i, to either of which the 
 moving power may be applied. The cloth is kept distended by a self- 
 acting tightening roller, which is screwed against the hopper k ; tliis 
 hopper receives the grain to be dried, and is provided with a shoe at l, 
 adapted to defiver a tliin and uniform stratum of grain upon the endless cloth, while the same is made 
 to pass under it, and over the trough. Another endless band m m, of a similar fabric to the other, 
 passes round the drums h i only, and is likewise provided with a self-acting tightening roller, fixable to 
 any convenient object. The lower ends of the six tubes a of the fireplace before mentioned have an 
 open communication with a rotative blower o, by means of a broad channel pp ; and the upper ends 
 of the tubes a also open into another broad channel q, which conducts the air into the long air-trough e 
 The operation of this machine is as follows : A slow rotation, derived from any first mover, is to be 
 given to either of the drums g h i, which will cause the endless cloth f to glide gradually over the 
 top of the air-trough e ; at the same time the blower o has been put into action (by connection with 
 the first mover) at a high velocity, so as to produce a rapid current of air, which derives an increase 
 of temperature on passing under the heated metallic bottom of the ash-pit ; hence proceeding through 
 the tubes a, it acquires considerable heat, which is subsequently moderated by an extensive diffusion 
 in the air-trough e, before it passes through the meshes of the endless cloth f above, carrying with it 
 the moisture from the grain deposited thereon. The course taken by the endless cloth is shown by 
 arrows in the figure : upon its arriving at the drum h, the other endless eloth m m comes in contact 
 with the grain on the cloth /, and, upon both the cloths passing round the said drum /(, the corn be- 
 comes inclosed between the two cloths, and is thus carried up an inclined plane over the drum 1, where 
 the cloths separate, and discharge (be grain back again into the hopper k, to undergo a repetition ol 
 the operation, should it not be perfectly dry. But when the grain is thoroughly dried, instead of allow- # 
 
 2466. 
 
156 
 
 KNEADING. 
 
 mg it to fall back into the hopper, a shoot, or the band of a creeper, (not shown in the drawing,) is 
 brought under the roller i, which conducts it to the required place. A very little experience in th* 
 working of this apparatus enables a person so to regulate its operations as to complete the drying o 
 
 damp grain by a single passage through it ; such as varying the velocity of the air-forcer, the quantity 
 of fuel in the stove, the supply of air through the ash-pit, the speed of the endless cloth, Ac., the means 
 of doing which arc so well understood by mechanics as to render a description of them unnecessary in 
 this place. 
 
 KITE. This well-known juvenile plaything has beer), applied to several objects of utility. The 
 most important of these is the invention of Captain Dansey, for effecting a communication between a 
 stranded ship and the shore, or, under other circumstances, where badness of weather renders the ordi- 
 nary means impracticable. The following is an abbreviated description of the invention, extracted from 
 the forty-first volume of the Transactions of the Society of Arts, where the subject is given more in 
 detail, with engraved illustrations : — A sail of light canvas or holland is cut to the shape, and adapted 
 for the application of the principles of the common flying kite, and is launched from the vessel or other 
 point to windward of the space over which a communication is required ; and as soon as it appears to 
 be at a sufficient distance, a very simple and efficacious mechanical apparatus is used to destroy its 
 poise and cause its immediate descent, the kite remaining, however, still attached to the line, and 
 moored by a small anchor with which it is equipped. The kite, during its flight, is attached to the line 
 by two cords placed in the usual manner, which preserves its poise in the air ; and to cause it to de- 
 scend, a messenger is employed, made of wood, with a small sail rigged to it. The line being passed 
 through a cylindrical hole in this messenger, the wind takes it rapidly up to the kite, where, striking 
 against a part of the apparatus, it releases the upper cord, and by that means the head of the kite be- 
 comes reversed, and it descends with rapidity. In the experiments made by Captain Dansey, with the 
 view of gaining communication with a lee-shore, under the supposition of no assistance being there at 
 hand, a grapnel, consisting of four spear-shaped iron spikes, was fixed to the head of the kite, so as to 
 moor it in its fall ; and in this emergency, the attempt of some person to get on shore along the line 
 would be the means resorted to. In those cases where a communication has been gained, and the 
 maintenance of a correspondence has been the object, the person to windward has attached a weight to 
 the messenger — in some cases as much as three pounds — which, having been carried up, has of course 
 descended with the kite ; the person to leeward has then furled the sail of the messenger, and loaded 
 it with as much weight as the kite could lift ; then replacing the apparatus, and exposing the surface 
 of the kite to the direct action of the wind, it has rapidly risen, the messenger running down the line 
 to windward during its ascent. The kite with which Captain Dansey performed the greater part of his 
 experiments extended 1100 yards of line, five-eighths of an inch in circumference, and would have 
 extended more had it been at hand. It also extended 860 yards of line 1} inches iu circumference, and 
 weighing 60 lbs. The holland weighed 8 \ lbs. ; the spars, one of which was armed at the head with 
 iron spikes, for the purpose of mooring it, 6 J lbs. ; and the tail was five times its length, composed of 8 
 lbs. of rope and 14 lbs. of elm plank. A complete model of the apparatus was deposited with the 
 society, who presented Captain Dansey with their gold Vulcan medal for his invention and communi- 
 cation. 
 
 KNEADING- is the process of making the stiff paste of flour and water for being afterwards baked 
 into bread. It is usually effected by a sort of pommelling action of the hands and arms, and some- 
 times of the feet of the bakers. A variety of machines have been at different times proposed for 
 superseding the barbarous process we have just mentioned ; they have, however, been but very par- 
 tially adopted, the bakers in general preferring to continue their “ good old-fashioned” dirty practice. 
 It is said that at Geneva all the bakers of that city are compelled by law to send their dough to be 
 kneaded at a public mill constructed for that purpose. At Genoa, also, mechanism is employed for 
 kneading : the apparatus employed at this place has been published in several of the journals, from 
 which it appears to be so rude and ill-contrived as not to need a description in this place. 
 
 1. The petrisseur, or mechanical bread-maker, invented by Cavallier and Co. of Paris, consists in a 
 strong wooden trough, nearly square, with its two longest sides inclined, so as to reduce the area of the 
 trough iu the direction of its width, and adapt it to the dimensions of a cast-iron roller, the axis of which 
 
KNITTING MACHINE. 
 
 157 
 
 passes through the ends of the trough ; the bottom of the trough is semi-cylindrical, leaving a smal. 
 space between it and the roller, which space is adjustable by levers. All along the top of the outside 
 of the roller is fixed a knife-edge, which, with the roller, divides the trough into two compartments. 
 U pon the axis of the roller is a toothed wheel, which takes into a pinion ; this pinion is turned by a 
 winch, and communicates thereby a slower motion to the roller; and the roller, by its rotation, forces 
 the materials or dough through the narrow space before mentioned left between it and the bottom o( 
 the trough — the knife-edge on the top of the roller preventing the dough from passing by it. Being 
 thus all forced into one of the compai tments, the motion of the roller is reversed by turning the winch 
 the contrary way, which then forces the dough back again through the narrow space under the roller 
 into the first compartment ; in this manner the working of the dough, alternately from one compart- 
 ment to the other, is continued until completed. 
 
 2. Another plan was to make the trough containing the dough revolve with a number of heavy ball? 
 within it. The trough in this case is made in the form of a parallelopipedon — the ends being square 
 and each of the sides a parallelogram, whose length and breadth are to each other as five to one. One 
 side of the trough constitutes a lid, which is removed to introduce the flour and water, and the trough 
 is divided into as many cells as there are balls introduced. The patentee states, that by the rotation 
 of the trough the balls and dough are elevated together, and by their falling down the dough will be 
 subjected to beating, similar to the operations of the baker’s hands. 
 
 3. Instead of employing a revolving cylinder, it is fixed, an agitator is made to revolve, having a 
 series of rings angularly attached to an axis, extending the whole length of the trough. 
 
 4. Mr. Clayton, a baker of Nottingham, had a patent in 1830 for a machine somewhat similar to the 
 last mentioned, inasmuch as a set of revolving agitators are employed to produce the kneading action. 
 The agitators are longitudinal bars, fixed to arms, which radiate from the axis, and they are forced 
 through the dough in their revolution ; but the cylinder in which they revolve, and which contains the 
 materials, is made to revolve at the same time in a contrary direction — the motion of the latter being 
 imparted by a short hollow axis, while the axis of the former is solid and passed through the hollow 
 one. The solid axis, which is turned by a winch, has on it a bevelled pinion, which, by means of an 
 intermediate bevelled wheel, actuates another bevelled pinion fixed on the hollow axis, and therefore 
 causes it to revolve in the opposite direction. These two simultaneous and contrary motions constitute 
 the novelty claimed by the patentee, who states , that dough-making machines similar to his own have 
 all failed for want of such an arrangement. This statement, coming from a baker, commands attention ; 
 but we cannot concur in its truth, since we know that the following plan of a kneading-machine works 
 well without opposite simultaneous motions, and without any agitators or beaters, which absorb a great 
 deal of power without producing an adequate effect. 
 
 6. Hebert’s patent kneading-machine. — In this a cylinder of from 4 to 5 feet in diameter, and only 
 aoout 18 inches wide inside, is made to revolve upon an axis, which is fixed by a pin during the revo- 
 lution of the cylinder. The flour is admitted by a door in the periphery, which closes air and water 
 tight ; and the water or liquor passes through a longitudinal perforation in the axis, and thence through 
 small holes among the flour, in quantities which are regulated externally by a cock. By the rotation of 
 the cylinder the dough is made to be continually ascending on one side of it, whence it falls over upon 
 the portion below. When the mixture becomes pretty intimate and uniform, its adhesive property 
 causes it to stick to the sides of the cylinder, and the dough would then be carried round without much 
 advancing the process, were it not for another simple contrivance. This is a knife-edge, or scraper, 18 
 inches long, which is fixed along the top of the cylinder in the inside, so as barely to touch its surface : 
 the knife is fixed to two flat arms extending from the axis, and these arms have sharp edges so as to 
 scrape the sides of the cylinder ; thus the cylinder is kept constantly clean from the sticking of the 
 dough, which, as soon as it ascends to the top of the cylinder, (if it does not tear away of itself,) is 
 shaved off by the knife, and falls down with great force upon the bottom ; and as this effect is constant 
 during the motion of the cylinder, it must be evident that the process of kneading is soon completed 
 by it- When that is done, the door of the cylinder is opened, and the contents discharged into a 
 recipient beneath ; at which time the scraper is caused, by a winch on the axis, to make one revolution 
 of the now fixed cylinder, which clears off' any adhering dough, and projects it through the doorway. 
 As the dough in this machine may be said to knead itself — there being no arms, beaters, or agitators 
 whatever — it is calculated that the power saved by it is very considerable ; while, from the simplicity 
 of its construction, the cost is moderate. 
 
 The patentee is at present engaged in combining with this kneading machine an apparatus for pre- 
 paring carbonated water, highly charged with the gas, with which he proposes to mix up the flour to 
 form dough, for the purpose of making the bread spongy or vesicular, without having recourse to the 
 fermentative process ; the result of which process, under the most favorable circumstances, he considers 
 to be detrimental to the health of those that eat the bread, (owing to the deposition of fermentable 
 matter in the stomach,) while it is destructive of a portion of the nutriment of the flour. 
 
 KNITTING MACHINE, Improved. From the specification of the inventor, J. R. Ellis, of Boston, 
 Massachusetts, patented June 17, 1851. Fig. 2469,* denotes a front elevation of the said improved 
 knitting machine. Fig. 2477 is a vertical and transverse section of it, the same being taken in such 
 manner as to exhibit the yarn guide or director, the stitch hook, and the contrivance for forcing the 
 work down towards the roots of the needles, after the formation of each new loop. Such other figures 
 as may be necessary to a proper representation of the various parts of my improvements, will be hereafter 
 referred to and described. 
 
 The machine as improved, is not what is usually termed a stocking loom, but is more properly named 
 a knitting machine, for the reason it forms each stitch of the work in regular succession, and not a num- 
 ber of stitches at once, as does the stocking loom. It is a machine in character like others in use, al- 
 
 Tho letters in the cut are by mistake made capitals instead of small letters. 
 
158 
 
 KNITTING MACHINE. 
 
 though it differs from the same in sundry important particulars which constitute my invention, and 
 which I shall hereafter describe. 
 
 In the drawings above mentioned, A denotes the endless chain belt of knitting-needles, which is so 
 made that the needles a a a, d'C., instead of being arranged or made to stand horizontally, and at right 
 angles to the vertical surface of the belt, are made to stand vertically or in the plane of the belt, as see>- 
 at a a a a, figures 2469 and 2477. 
 
 The driving pinion b, instead of being arranged within the belt as it has been in other machines of 
 this character^ is disposed on the exterior surface of it, and works against, or with the projecting points 
 of the belt. That part of the inner surface of the belt, which is immediately adjacent to the pinion, i 
 supported by, and works round a stationary vertical post or guide c, (see fig. 2471, which is a vertical sec- 
 tion of the belt and its support) that extends upwards from a horizontal arm d, which projects from the 
 
KNITTING MACHINE. 
 
 159 
 
 main frame B. The opposite end of the endless belt is supported by a straining contrivance L, which 
 is similar to such as are in common use in such machines. The work or knitting hands within is the 
 endless belt, instead of without it, or on the outside of it. 
 
 The yarn guide or director is seen at D. It consists of a curved arm, made to extend from a hori- 
 zontal rocker shaft f and to have a small conical and split tube y, on its outer end, through which tube 
 the yarn is carried from the bobbin placed in any convenient position. 
 
 The stitch hook is seen at E. It is arranged in rear of the chain belt of needles, and is formed as 
 represented in side view on an enlarged scale, fig. 2472, that is to say, it is made not only with a hooked 
 end, as seen at h, but with a shoulder i, a short distance in rear of said hooked end, the shoulder per- 
 forming the important office of piercing or casting the loop (taken up by the hook) over the hooked 
 point of the needle, the same having been effected in other machines of this kind, by what is usually 
 termed the “bent finger.” By my improvement I am enabled to dispense with such bent finger, and the 
 machinery for operating it. In order that the stitch hook may not only take up the loop, but cast it over 
 the end of the needle and the yarn laid on the needle by the yarn director, and this to form or make a 
 new stitch, the hook should have the following movements imparted to it. First, it should be made to 
 
2 GO 
 
 KNITTING MACHINE. 
 
 pass into the groove of the needle, and under the stitch on the needle. Next, it should be made to rise 
 upwards so as to carry the stitch up to the hooked end of the needle. Next, it should be moved late- 
 rally far enough to be opposite the space between the needle (first operated upon) and the next needle. 
 Next, it should be moved forwards between the two needles and so as to cause the shoulder i, to press or 
 force, or cast the stitch over the hooked end of the needle. The stitch hook should next be drawn 
 backwards, and depressed so as to disengage it from the stitch. The movements of the stitch hook may 
 be produced by various kinds of combinations of mechanism. No such machinery forms any part of 
 my invention, and I lay claim to none in particular, but employ such as may be suitable : that adopted 
 by me is as follows, viz : 
 
 2478 2477 
 
 The stitch hook E, is fastened to the lower end of a bar o', which works or slides freely up and down 
 through a piece of metal b', and is jointed by a joint screw c', to a connecting rod d ', on whose upper 
 end is a strap^/", passing around an eccentric g\ fixed on the main driving shaft A', of the machine. 
 The upward and downward movements of the stitch hook are effected by such eccentric during its en- 
 tire revolution. In order to produce its forward and back movements, a lever i', working on a fulcrum 
 Jc\ is jointed at its lower end to the rear end of the piece of metal b'. The upper end or arm of the said 
 lever rests against a cam t', fixed on the driving shaft (see fig. 2473,) which denotes a top view of the 
 said shaft, and the cams applied to it. See also figures 2474 and 2475, the former of which is a side 
 view of the said cam, and the wing cam to be hereinafter described, while the latter is a top view of 
 the same, made so as to show the form of the wing cam. During the revolution of the cam the lever 
 i' will be moved forwards and backwards by the action of the said cam and a spring m , made to bear 
 against the rear side of the said lever. The small wing cam n ' , placed on the side of, or to project 
 above the cam l', serves to press the upper end of the lever i laterally, in order to produce the lateral 
 motion of the stitch hook. A spring o', (see fig. 2473,) presses the end of the lever i, against such 
 wing cam. 
 
 Both the stitch hook and the yarn guide, are arranged between the arms of the presser, which presser 
 consists of two arms, k , l, extended at right angles from a horizontal rocker shaft m, and long enough 
 to play between the needles. These arms should be made to operate so as to press the work down to the 
 roots of the needles, after the formation of each stitch; they should next be raised upwards far enough 
 to allow of the movement of the chain belt, which having taken place, they should be depressed so as 
 to hold the work down until the stitch hook has fairly hooked under or taken up the stitch on the nee- 
 dle, against which it may be acting. 
 
 The presser should next be elevated with the stitch hook, so as to allow the work -to rise. While the 
 stitch hook is casting the stitch or loop over the hook of the needle, the presser should be stationary, but 
 as soon as this has been effected, and the hook has withdrawn itself from the stitch, the presser should 
 be depressed so as to force the work down to the roots of the needles. Such movements may be attained 
 by any suitable machinery applied to the rocker shaft of the presser, such mechanism constituting no 
 part of my invention; — but that which I employ may be thus described: — Fig. 2476 is a front elevation 
 of the machine as it appears when its front plate p', and the endless chain A, are removed from the re- 
 
KNIVES. 
 
 16 j 
 
 mainder of the mechanism. Fig. 2470 is a vertical cross section of the machine; the same being ta- 
 ken looking towards the left through the cam, which operates the presser. 
 
 From the shaft m of the presser, an arm q' extends towards the front, and is joined at its outer end 
 to an upright and bent bar r', whose upper end is forced upwards against the cam s', by means of a 
 spring t' , one end of which is attached to the bar r , and the other to the frame or box B, as seen in 
 figs. 2476 and 2470. The cam s' is fixed on the driving shaft, and during its revolution, it, in conjunc- 
 tion with the spring t' , produces the rocker motions of the shaft m , such as will cause the presser to op- 
 erate in the manner required. 
 
 Directly after each movement of the chain belt, the yarn guide or director D, should be moved for- 
 ward beyond the back needles, so as to lay the yarn on that needle on which the new stitch is to be 
 made. After the stitch lias been formed, the yarn guide should be retrograded and carried back of the 
 needles, in order that the chain belt may perform its next movement without obstruction. The mechan- 
 ism for operating the yarn guide or director D, consists of a cam u', fixed on a driving shaft, a slide 
 rod or bar v', (whose lower end is jointed or hinged to the outer end of an arm w', extended from the 
 shaft f) and a spring x', which forces the bar v' up against the cam — the said cam being shown in fig. 
 2470 by dotted lines. 
 
 The machinery for moving the chain belt forms no part of my invention, except so far as the arrange- 
 ment of the gear or pinion B and the joints x x x, &c., of the chain belt is concerned. On the main 
 driving shaft, there is another cam a 2 , which operates against the upper end of a lever b 2 , which turns 
 upon a fulcrum e 2 . See fig. 2478, which is a transverse section of the machine, taken through such cam, 
 and looking towards the right, serves to show the machinery actuated by it. A spring d 2 , is used to 
 draw the upper end of the lever against the cam. The lower end of the lever is bent at right angles, 
 or horizontally, and has two impelling pawls e 2 y 2 , jointed to it, and made to extend forwards, and re- 
 spectively to act in concert with two ratchet wheels y 2 7i 2 , fixed upon the upright shaft P, of the pinion b 
 which works the chain belt. These ratchet wheels and pawls are seen in fig. 2477 and 2479, the latter 
 figure being a horizontal section of the machine, taken just above the pawls, and so as to exhibit them. 
 The teeth of one of the ratchet wheels are arranged in a direction opposite to those of the other, in or- 
 der that when its pawl is in action with it, a motion of the shaft * 2 , may be produced in a direction the 
 reverse of that effected by the movements of the other pawl and its wheel. By the movement of either 
 pawl an intermittent rotary motion of the shaft P will take place. 
 
 The two pawls pass respectively through slots TP P, made in a vertical stationary plate m ? ; (see fig. 
 2480,) which is a front view of the plate rrP, and the shifting contrivance attached to it. Such shifting 
 contrivance is a slide n 3 , which is capable of being moved longitudinally, and has a projection o 2 extend- 
 ing down between the two pawls. When the slide is moved in one direction, it bears against one of the 
 pawls, and throws it out of action upon its ratchet wheel, and at the same time, in consequence of the 
 two pawls being connected by a spring p 2 , it draws the other pawl against the other ratchet wheel, 
 thereby creating a reverse motion of the shaft P. The object of the two pawls is to enable the move- 
 ment of the endless belt A to be reversed, so as to cause the knitting to be produced in an opposite di- 
 rection ; one pawl, however, is sufficient to produce the movement necessary to knit in one direction. 
 
 The shaft f which carries the yarn director D, is made to slide longitudinally in its bearings, and is 
 connected into the slide ri 1 , by a lever <f, rvhich turns upon a fulcrum r 2 , and has its ends inserted in 
 notches made in the slide rP, and the shaft f and this so that the movement of the slide in one direction 
 may create a sliding movement of the shaft, sufficient to move the yam guide into the proper position 
 to commence the knitting in the reverse direction. 
 
 The shifting contrivance may be operated by the attendant, or by any other proper means. Some 
 parts of other mechanism which I append or attach to the above described machine, and for pur-poses 
 not necessary to mention, may be seen in the drawings. As such mechanism forms no part of my in- 
 vention, I make no further reference to it or description of it. 
 
 On the driving shaft there may be a fly wheel P, from which a crank s 2 may extend, and for the pur- 
 pose of enabling a person to put the shaft in motion — or the said shaft may be revolved by a pulley ap- 
 plied to it, and made to receive an endless belt from any suitable driving drum. 
 
 By having the endless chain of needles made and operated in the above described manner, the chain 
 extends around the work, instead of the work encompassing the chain, as it does in other well-known 
 knitting machines. My improved arrangement and disposition of the work exposes all the joints of the 
 links of the chain so that a workman or attendant can readily remove one or more of the needles, with 
 much greater convenience than can be done on the said well-known machines, as in the latter he would 
 be obliged to wholly or partially remove the work from the needles in order to accomplish the addition or 
 subtraction of one or more of the needles, such addition or subtraction being for the purpose of enabling 
 him to “ widen ” or '•'•narrow’" the work. My improvement affords great advantages in knitting a heel, 
 as the same can be effected in a much more perfect manner, without that strain upon the work and nee- 
 dles that is incident to the old and well-known machines, 
 
 KNIVES, ( including Forks) Knives are well-known instruments, made for cutting a great variety 
 of substances, and adapted by differences in form to various uses ; but the two principal sorts may be 
 classed under the terms of pocket-knives and table-knives, with then- accompaniments, forks. 
 
 In the making of pocket-knife blades, one workman and a boy are generally employed ; the boy 
 attends to the heats, (that is, to the rods: of steel in the fire,) which he successively hands to the forger, 
 and takes back the rod from which the last blade was formed. One heat is required to fashion the 
 blade, and a second to form the tang, by which it is fastened into the handle. The skill of the forger 
 is displayed in forming it so perfectly by his hammer, as to require but very little to be filed or ground 
 off in the subsequent operations. The springs for the back of the knife, and the scales which form the 
 rough metal under-handle, and to which the other pieces are riveted, are made by a distinct class ol 
 workmen. In the forging of table-knife blades, and other blades of a similar or greater size, the forger 
 has an assistant, who, with a large hammer, strikes alternately with him ; and the hammering of all 
 
 . Vol. ii.— n 
 
162 
 
 KNIFE-SHARPENERS. 
 
 blades is continued after tlie steel has ceased to be soft, in order to condense the metal and render it 
 very smooth and firm. Table-knife blades are usually made with iron backs, which are welded to the 
 steel by a subsequent forging, to that of forming the cutting edge ; the thick piece that joins the han- 
 dle, called the shoulder or bolster, as well as the tang that goes through the handle, is forged out of the 
 iron immediately after the welding of the steel blade : dies and swages being employed to perfect and 
 accelerate the shaping of these parts. When the forging is completed, the blades undergo the processes 
 of hardening and tempering, explained in article Tempering. The blades are then ground upon a wet 
 stone, about 4 feet in diameter, and 9 inches wide, which roughs out the work ; they are subsequently 
 finished or whitened, as it is termed, upon a finer dry stone; and the shoulders or bolsters are ground 
 upon a narrow stone, about 3 feet in diameter, which completes the grinding. The next process is that 
 of glazing the blades, which is effected upon a wooden wheel, made up of solid segments, well fitted 
 and secured together, and with the ends of the fibres of the wood presented to the periphery of the 
 circle ; over this is extended a piece of leather, which is charged with emery or other powders, adapted 
 to the finish or nature of the work required. 
 
 The cheaper kind of forks are made by casting them from malleable pig-metal, sometimes denom- 
 inated “ run-steel ;” and some of these, which are well annealed and worked under the hammer, turn out 
 very serviceable and good. Those made of wrought-metal, were formerly either forged, and the prongs 
 drawn out by the hammer, and welded together, or they were forged into one solid piece, and the 
 spaces between them formed by cutting away the metal. These processes, however, were tedious and 
 expensive, and a great improvement in their manufacture has been introduced. The tang, shoulder, 
 and a thick, flat piece, called the blade, are forged, and the blade is then submitted to the action of a 
 pair of dies, contained in a powerful fly or stamping-press; the dies being so formed as to force or cut 
 out the superfluous portion of the metal and raise the curved swelled portions at the junction of the 
 prongs, termed the bosom. The forks after this operation are filed up, ground, glazed, and burnished, 
 when they are ready for hafting, which is a distinct business. 
 
 The instruments required for hafting knives and forks are few and simple. The principal are, a small 
 polishing-wheel and treddle, mounted upon a stand, a bench vice, and a kind of hand vice to fix in the 
 bench vice, termed a snap-dragon ; it has a pair of long projecting jaws, adapted to hold a piece of 
 metal or other substance, with the flat side uppermost, in order to be filed or otherwise worked ; a few 
 files, drills, drill-box, and breast-plate, burnishers and buff's, emery, rotten-stone, <fcc. The substances 
 used for covering the handles are almost infinite ; the chief are bone, horn, ivory, tortoise-shell, and wood 
 of every kind. The several pieces of the handle being filed to the shape intended, holes are drilled 
 through them for the pins by which they are afterwards riveted together. The pinning is at first 
 loosely done, until the blades, springs, and all the parts are well adjusted and fit closely ; they are then 
 firmly riveted together. The handles are afterwards scraped and then polished, by means of buffing, 
 on the wheel. 
 
 KNIFE-SHARPENERS. This term has been 2469. 
 
 given to a variety of convenient modern instru- 
 ments, especially adapted to the sharpening of 
 knives at table, but particularly carvers, and are 
 intended as substitutes for the coipmon ‘steel. For 
 these instruments several patents have been ob- 
 tained, and a considerable manufacture of them has 
 been established. 
 
 Filton’s patent sharpener, represented in Fig. 
 
 2469, consists of two horizontal rollers, placed par- 
 allel to each other, which revolve freely upon their 
 axes, (represented by the two black dots ;) at uni- 
 form distances, there are fixed upon each roller 
 narrow cylinders or rings of hard steel, the edges of which are cut into fine teeth, and thus form circular 
 files ; the edges of the files in the opposite rollers overlap each other a little, so that when a knife is 
 drawn longitudinally between them, the edge of the knife is acted upon on both of its sides at once. 
 The rollers turn round with the slightest impulse ; consequently, they wear uniformly, and will last a 
 considerable time. A good edge is given to a knife by just drawing it from heel to point two or three 
 times between the rollers ; and thus obviates the necessity of imitating the skill exercised by a butcher 
 upon his steel. 
 
 Westbfs knife-sharpener, which was patented in 1828, is an ingenious instrument; an immense quan- 
 tity of them have been sold, and it is said, have been the means of greatly enriching the proprietor of 
 the patent. Fig. 2470 exhibits an end elevation of the instrument, and Fig. 2471 a side elevation of the 
 bars, with a section of the boxes a and h, to show the interior. The same letters in each figure have 
 reference to similar parts ; a is a small oblong box, surmounted by a smaller box h ; in the top of the 
 latter there is a slit made throughout its length, and of sufficient width to receive the square steel 
 bars c c. The box a has two similar slits. The surfaces of the bars are draw-filed ; they pass through 
 the slit in h, and alternately through both slits in a, so as to cross each other, as shown in Fig. 2470. 
 The lower ends of these bars are supported upon a plate of metal d, which can be elevated, so as to 
 bring a different portion of the bars into operation, by means of the screw underneath ; ff are two 
 screws passing through the holes in d, to preserve its parallel motion, and likewise to support the bottom 
 of the box ; h is a tightening screw to steady the bars c c. 
 
 The mode of operating with this instrument is merely to place the edge of the knife upon the bars, 
 so as to bisect the angle formed by them, and then draw the knife backward and forward. As the 
 surfaces of the bars wear away, different sides can be presented, or they can be shifted from end to 
 end, so as to present fresh surfaces to the knife. 
 
 Church's pa io nt knife-sharpener consists of two very flat truncated cones, fixed with their smaller 
 
LAC. 
 
 163 
 
 surfaces together, and with several rectangular projections in the one, fitting into similar cavities in the 
 other. The conical surfaces of both pieces are serrated with a series of very fine teeth extending an- 
 gularly towards their centres ; these are placed upon the shank of the fork, between the shoulder and 
 the handle, with which they correspond in diameter so nearly as to constitute an ornamental finish to 
 the small end of the handle. In the position and size of these consist the principal merit of the sharp- 
 ener. When used for sharpening scythes, or other large cutting instruments, the conical pieces are 
 made larger, and fitted on an axis between two prongs of a forked apparatus, with an appropriate 
 handle. 
 
 2471. 2470. 
 
 Westhy's second patent . — The extraordinary success attendant upon Mr. Westby’s contrivance for 
 sharpening table-knives induced him to figure a second time as a patentee, “ for certain improved ap- 
 paratus to be used for the purpose of whetting or sharpening the edges of the blades of penknives , 
 razors, and other cutting instruments.” The first improvement mentioned in the specification consists 
 in the application to a hone, or oil-stone, of a guide to keep the edge of the razor, or other cutting in- 
 strument, at the same angle with respect to the surface of the hone, during the operation of whetting. 
 This is effected in two ways : first, by placing over the hone a plate of metal extending its whole length, 
 and adjustable, at any required distance parallel to its surface, by set-screws ; now, in the operation ot 
 sharpening, the back of the instrument is kept resting upon the guide-plate, while the edge is applied 
 to the hone. The second method consists in the application of two hones placed in an erect position, 
 with a space between them for the razor, which is to be fixed by screws into a small horizontal frame, 
 made to slide upon a circular rod, so that the edge can be applied alternately to the hones ; these can 
 be elevated and depressed at pleasure, so that, their surfaces may be uniformly worn while in use. The 
 patentee also mentions in his specification a method of attaching to his hone a leather strap which is 
 made double, and kept stretched by adjusting screws attached to the frame of the hone, or else to the 
 end of a rod extending lengthwise between the two folds of leather. This last contrivance does not 
 appear to us to be scientifically adapted to the object in view, as the pressure of the edge of the instru- 
 ment upon a strap of leather only supported at its extremities, must produce a tendency in the leather 
 to wrap round the acute angle of the edge of the instrument, and render it obtuse. 
 
 LABURNUM WOOD is in use among turners • pulleys and blocks are made of it. Being a hard 
 and compact wood, it is capable of endurance when exposed to the weather, and for various purposes 
 is extremely valuable. When perfectly dry, a cubic foot weighs 52 lbs. 11 oz. 
 
 LAC. A resinous substance, the product of an insect found on several different kinds of trees in the 
 East Indies. These insects pierce the small branches of the trees on which they feed, and the juice 
 that exudes from the wounds is formed by them into a kind of cells for their eggs. Lac is imported 
 into this country adhering to the branches in small transparent grains, or in semi-transparent flat cakes. 
 The first, encrusting the branches, is called stick-lac ; the second are the grains picked off the branches, 
 and called seed-lac ; the third is that which has undergone a simple purification, as we shall presently 
 notice. There is a fourth, called lump-lac, made by melting the seed-lac, and forming it into lumps. 
 To purify the lac for use the natives of India put it into long canvas bags, which they heat over a 
 charcoal fire until the resin melts ; a portion of the lac then exudes through the bags, which are subse- 
 quently twisted, or wrung by means of cross sticks at the ends of the bags, the surface of the latter 
 being scraped at the same time to accelerate the process. The chief consumption of lac in this country 
 is in the manufacture of sealing-wax and varnishes. It has been a great desideratum among artists to 
 render shell-la.c colorless, as, with the exception of its dark-brown hue, it possesses all the properties 
 essential to a good spirit varnish in a higher degree than any other known resin. The process given 
 by Dr. Hare leaves nothing to desire, excepting on the score of economy. Were the oxymuriate of 
 potash to be manufactured in the large wav, the two processes, that of making the salt and of bleach- 
 ing the resin, might be advantageously combined. “ Dissolve in an iron kettle one part of pearlash in 
 
164 
 
 LACTOMETER. 
 
 about eight parts of water ; add one part of seed or shell lac, and heat the whole to ebullition ; when 
 the lac is dissolved, cool the solution, and impregnate it with chloriue till the lac is all precipitated. 
 The precipitate is white, but its color is deepened by washing and consolidation ; dissolved in alcohol, 
 lac bleached by the process above mentioned yields a varnish which is as free from color as any copal 
 varnish.” 
 
 The following is Mr. Field’s process : Six ounces of shell-lac, coarsely powdered, are to be dissolved 
 by gentle heat in a pint of spirits of wine ; to this is to be added a bleaching liquor, made by dissolving 
 purified carbonate of potash, and then impregnating it with chlorine gas till the silica precipitates and 
 the solution becomes slightly colored. Of this bleaching liquor add one or two ounces to the spirituous 
 solution of lac, and stir the whole well together ; effervescence takes place, and when this ceases, add 
 more to the bleaching liquor, and thus proceed till the color of the mixture has become pale. A second 
 bleaching liquor is now to be added, made by diluting muriatic acid with thrice its bulk of water, and 
 dropping into it pulverized red lead, till the last added portions do not become white. Of this acid 
 bleaching liquor, small quantities at a time are to be added to the half-bleached lac solution, allowing 
 the effervescence, which takes place on each addition, to cease before a fresh portion is poured in. This 
 is to be continued until the lac, now white, separates from the liquor. The supernatant fluid is now to 
 be poured away, and the lac is to be well washed in repeated waters, and finally wrung as dry as pos- 
 sible in a cloth. The lac obtained in the foregoing process is to be dissolved in a jjint of alcohol, more 
 or less, according to the required strength of the varnish ; and after standing for some time in a gentle 
 heat, the clear liquor, which is the varnish, is to be poured off from the sediment. 
 
 Mr. Luning’s process is as follows : — Dissolve five ounces of shell-lac in a quart of rectified spirits of 
 wine ; boil for a few minutes with ten ounces of well-burnt and recently heated animal charcoal, when 
 a small quantity of the solution should be drawn off and filtered : if not colorless, a little more charcoal 
 must be added. When all color is removed, press the liquor through silk, as linen absorbs more varnish, 
 and afterwards filter it through fine blotting-paper. In cases where the wax found combined with the 
 lac is objectionable, filter cold ; if the wax be not injurious, filter while hot. This kind of varnish 
 should be used in a temperature of not less than 60° F. ; it dries in a few minutes, and is not after- 
 wards liable to chill or bloom ; it is therefore particularly applicable to drawings and prints which have 
 been sized, and may be advantageously used upon oil pointings which have been painted a sufficient 
 time, as it bears out color with the purest effect. This quality prevents it from obscuring gilding, and 
 renders it a valuable leather varnish to the bookbinder, to whose use it has already been applied with 
 happy effect, as it does not yield to the warmth of the hand, and resists damps, which subject bindings 
 to mildew. Its useful applications are very numerous, indeed, to all the purposes of the best hard 
 spirit varnishes ; it is to be used under the same conditions, and with the same management. Common 
 seed-lac varnish is usually made by digesting eight ounces of the bright, clear grained lac in a quart ot 
 spirits of wine, in a wide-mouthed bottle, putting it in a warm place for two or three days, and occa- 
 sionally shaking it. When dissolved it may be strained through flannel into another bottle for use. In 
 India, lac is fashioned into rings, beads, and other trinkets. Its coloring matter, which is soluble in 
 water, is employed as a dye. The resinous portion is mixed with about three times its weight of finely 
 powdered sand, to form polishing stones. The lapidaries mix powder of corundum with it in a similar 
 manner. 
 
 LACE. A delicate kind of net-work, composed of silk, flax, or cotton threads, twisted or plaited 
 together. See Bobbin-work. 
 
 LACQUERING is the application of transparent or colored varnishes to metals, to prevent their 
 becoming tarnished, or to give them a more agreeable color. The basis of them is properly the lac 
 described in the preceding article ; but other varnishes made by solutions of other resins, and colored 
 yellow, also obtain the name of lacquer. Strictly speaking, lacquer is a solution of lac in alcohol, 
 to which is added any coloring matter that may be required to produce the desired tint ; but the 
 recipes that have been published in various scientific journals contain apparently a great many useless 
 articles. 
 
 | oz. of terra merita, 
 
 2 oz. of oriental saffron, 
 
 3 oz. of pounded glass, 
 
 and 
 
 20 oz. of pure alcohol. 
 
 Lacquer for Brass. 
 
 oz. of gum guttre, 
 
 2 oz. of gum sandarac, 
 
 2 oz. of gum elemi, 
 
 1 oz. of dragon’s blood, of the best quality, 
 
 1 oz. of seed-lac, 
 
 Before, however, the reader ventures to meddle with so formidable a list of ingredients as the fore- 
 going, we would recommend him to make trial of the following more simple compound: — Take 8 oz. 
 of spirits of wine, and 1 oz. of annatto, well bruised ; mix these in a bottle by themselves ; then take 
 1 oz. of gamboge, and mix it in like manner with the same quantity of spirits. Take seed-lac varnish, 
 (described under the previous article Lac,) what quantity you please, and color it to your mind with 
 the above mixtures. If it be too yellow, add a little from the annatto bottle ; if it be too red, add a 
 little from the gamboge bottle ; if the color be too deep, add a little spirits of wine. In this manner 
 you may color brass of any desired tint : the articles to be lacquered may be gently heated over a 
 charcoal fire, and then be either dipped into the lacquer, or the lacquer may be evenly spread over 
 them with a brush. 
 
 LACTOMETER. An instrument for the purpose of ascertaining the different qualities of milk from 
 its specific gravity compared with water. On this subject Dr. Ure observes, that it is not possible to 
 infer the quality of milk from the indications merely of a specific gravity instrument, because both 
 cream and water affect the specific gravity of milk alike. “We must first use as a lactometer a gradu- 
 ated glass tube, in which we note the thickness of the stratum of cream afforded, after a proper inter 
 val, from a determinate column of new milk ; we then apply to the skimmed milk a hydrometric 
 
LAMPS. 
 
 165 
 
 Thus the combination o f 
 
 2472. 
 
 instrument, from which we learn the relative proportions of curd and whey, 
 the two instruments furnishes a tolerably exact lactometer.” 
 
 Frye's lactometer. — Fig. 2472, for testing the quality of milk; made under the 
 direction of the Board of Agriculture of the American Institute, in the city of New 
 York, who have strongly recommended it to public patronage. 
 
 This instrument was invented for the purpose of ascertaining the density, and fixing ^ ^ ^ 
 
 the standard weight, of pure unadulterated milk, as it is produced in the best grazing ^j/water." 4 
 districts in the country, and with a view of detecting the frauds practised by adulter- 
 ating milk with water, so often complained of by the consumer, in large towns and milk and 
 cities throughout the Union. ^ water ' 
 
 Directions for using the instrument . — Fill the tin tube, which accompanies the in- % milk and 
 strument, with the milk to be tested at a temperature of about 60 degrees, and sus- ^ " ,Ilter ' 
 pend the lactometer in the milk, and if the milk is proof, the instrument will sink to p ^ 
 the degree marked 100 on the scale, or p, showing that the milk is at par ; but if the Co. niiTk/ e 
 milk has been adulterated with water, or has been taken from cows that have been 
 fed on slops from breweries, and kept confined in stables in warm weather, the instrument 
 will, in all such cases, sink below par, and show the per centage of adulteration, which, in 
 some instances, will be 25 per cent, below par ; but if the milk is superior, the instrument 
 will rise above p, and show the per centage above par, which, in some instances, will be 10 
 per cent. Each division on the scale is 5 per cent. 
 
 Any person can test the correctness of the lactometer by mixing water with pure milk, 
 and note the per centage of water which they use, and suspend the instrument in the mix- 
 ture, and it will give the proportion of water added. 
 
 To farmers the instrument has proved to be very valuable, as a ready means of testing the relative 
 quality of their cows, by inspecting their milk, and also showing the effects produced by a change ol 
 the animals’ food, as its quality will change the density of the milk. 
 
 L ADDER. A portable frame, containing steps for the feet. There are various kinds, most of which 
 are too familiar to the readers of this work to need description. Ladders are very advantageously em- 
 ployed in the raising of weights, by the addition of a pulley-wheel at the top, or suspended over them ; 
 passing over this pulley is a rope, to one end of which is attached the article to be raised. 
 
 Ladders are the universal means of ascent and descent in mines, the distance between the levels 
 being generally 60 feet ; a single ladder in former times reached from one to the other, but the most 
 usual length at present is from 4 to 5 fathoms. In the perpendicular shafts the inclination is commonly 
 such that the ladder may nearly traverse the breadth of the shaft; from 18 to 21 inches in the fathom 
 is the inclination which experience has determined to be the best calculated to facilitate the progress ot 
 the miner, being that which enables him to stand upright on the ladder with the leg clear from the 
 stave above, so that the effort is divided between the upper and lower extremities. The distance 
 between the staves is generally 12 inches ; in some old ladders they were 14 inches apart, but 10 inches 
 is found the best for facilitating the climbing, by which one-fourth of the labor is estimated to be saved. 
 The staves are of wood, though iron is in some instances preferred ; in others it becomes slippery and 
 rough from the corrosive action of water impregnated with copper, &c. Each ladder usually terminates 
 on a sollar or platform, which leads to that below, which is generally placed parallel to that above. 
 
 LAMPS. The whole series of improvements made in lamps up to the present time, must be con- 
 sidered as the reward of no inconsiderable expenditure of ingenuity in the inventors themselves, and of 
 a clear perception of the working of physical laws, enabling them not only to overcome the difficulties 
 of the subject itself, but also to adapt the new contrivances to general use, and to the management of 
 the unskilled. A general view of this interesting subject will place clearly before us the essential points 
 which it has been the object of the inventors to attain, sometimes singly, sometimes several at once. 
 They are these : 
 
 (а) To select such a form (section) of wick that the quantity of decomposed oil, and the simultaneous 
 supply of air, may stand in such relation to each other, that the hydrogen and carbon may be con- 
 secutively consumed, and consequently no smoke produced. 
 
 (б) To make the distance between the burning part of the wick and the surface of the oil as un- 
 changeable as possible, in order that as much oil may be drawn up at last as at first. 
 
 (c) To place the reservoir of oil in such a position that the shadow shall occasion little or no incon- 
 venience. The use made of the lamp must, of course, here regulate its form ; it is not, however, always 
 a fault when these do not exactly correspond. Thus the shadow thrown bv wall lamps is unimportant, 
 as the lamp itself covers the shadow : in like manner, the shadow of a common study lamp cannot be 
 considered as a fault/being used only by one person, although its prevention is always an improve- 
 ment. 
 
 (d) To throw the light, radiating from the flame, by means of collectors and reflectors, from those 
 parts where it is of little service, in the direction where it is most required. 
 
 The requisitions stated under a have been complied with in two ways : on the one hand, by controlling 
 the access of air, (the quantity of air ;) on the other, by regulating the supply of oil, and often by both 
 at the same time. They have reference to that part of the lamp called the burner. 
 
 The scrupulous enumeration of the manifold modifications, and, for the greater part, unimportant 
 improvements in lamps, which have been presented to the public during the last twenty or thirty years, 
 would be but a tedious labor ; and in the following observations we shall only lay before the reader 
 those inventions which appear to indicate important progress, or form epochs in the history of this 
 subject. 
 
 Worms lamp . — The Worms’ lamp, shown in Figs. 2473 and 2474, is well known, and characterized 
 by the shape of the wick t. The fibres of the wick, instead of being collected into a round bundle, are 
 placed in small bundles side by side, forming together a flat ribbon. The effect of this is obvious. The 
 
LAMPS. 
 
 ieo 
 
 edges of the flame are at 'no point so distant that a nucleus can form in the centre, which, from want of 
 air, will burn incompletely and smoke. The flat socket c serves to hold the wick ; it is soldered in 
 the diameter of the wide ring d, which, with its recurved edge, rests upon that of the glass globe a a. 
 An important addition to its flat form is its movability , and this is common to all the following kinds 
 of lamps. The teeth of a wheel e and e', more distinctly seen in Fig. 2474, are somewhat advanced into 
 the space occupied by the wick, a cut being made in the socket, so that they press the wick in some 
 measure against the back side. According as the screws are turned the wick is either raised or lowered, 
 and a larger or smaller portion of it is engaged in the combustion. When the wick is high a large 
 auantity of oil is decomposed ; and when low a small quantity in the same space of time : the supply 
 of oil is, therefore, easily regulated. 
 
 2474. 
 
 2473. 
 
 By means of the stem a the oil vessel can be placed upon any kind of foot. Besides the very un- 
 equal, constantly decreasing height of the surface of the oil, another objection may be raised to this 
 arrangement, on account of the size and disadvantageous direction of the shadow, the conical space 
 between /and jig receiving no direct light. 
 
 Study lamp . — In the common study lamp, Fig. 2475, the oil vessel a is more flat, and instead of being 
 situated below, is behind, and at the side of the flame, so that its shadow falls much beyond the imme- 
 diate vicinity of the flame, and in no way interferes with the person in front of the lamp. The greater 
 part of the light passing upwards, is collected by the shade k, and from every point of its inner surface is 
 reflected downwards towards the opposite side. The inclination of the sides of the conical shade is, there- 
 fore, not unimportant, and should be at an angle of about 60°. The shade can be turned on the support m n. 
 The motion communicated to the wick d is not from above, as in Figs. 2473 and 2474, in which arrange- 
 ment the pressure interferes too much with the supply of oil, and the flame is too much cooled by the 
 proximity of the wheels, but it is from below. The clamp u. Fig. 2476, which sustains the wick, is firmly 
 connected with the toothed rod e. By turning the wheel o, this and the wick is raised up or down ; the 
 wheel works in the separate compartment g, as does the toothed rod in descending into h, whilst the 
 clamp, the rod of wire, and the wick, by means of a rectangular appendage c, Fig. 2477, are all inclosed 
 in the space allotted to the burner. This communicates with the oil vessel through the tube b ; i is the 
 inclosure round the burner. The motiou of the wick, by means of a toothed rod and wheel, is, under 
 various modifications, common to most lamps. The stopper l , at the aperture for filling the oil vessel, 
 must be pierced, that the air without may not depress the oil in the burner. 
 
 The astral lamp . — The astral lamp, of which a sketch is given in Fig. 247 8, was constructed by Bordier- 
 Marcet, with the idea of making as imperceptible as possible the sinking of the level of the oil, and at 
 the same time the diminution of the flame by means of a very flat oil vessel, in which, therefore, a 
 larger quantity of oil only occupies a very insignificant height. It is clear that the annular flat oil 
 vessel will produce only a small unimportant shadow, although this will necessarily be thrown on all 
 sides. At the same time the side nearest the flame a a is so inclined that it acts like a shade. Th : 
 burner is not peculiar to the astral lamp, but is the well-known invention of Ami Argand, in 1789, and 
 named after him; it is by far the most important kind of burner employed for illuminating purposes. 
 The Argand burner, with double draught, consists of two metallic cylinders, one within the other, « 
 and d: the ring-shaped space between them, which is closed at bottom, contains the oil and tbo 
 lyliudrically woven wick ; the latter is clamped between two rings, which are connected with the screw. 
 
LAMPS. 
 
 167 
 
 The inner cylinder is open at top and bottom. The extraordinary advantages of this arrangement art 
 easily understood. It has been already shown that with entire (massive) wicks, a nucleus is formed in 
 the middle of the candle, which illumines but little, and smokes from want of air ; with the hollow wick 
 a current of air is directed exactly to that spot, so that the flame is surrounded by two concentric cur- 
 rents of the same kind. The current produced in the air by a freely burning hollow-wick flame, or the 
 natural supply of air, is by no means sufficient to produce the requisite amount of light. As soon as, bs 
 
 2476. 
 
 raising the wick, the size of the flame is increased, a thick smoke is the result ; and when the wick is sc 
 regulated as to produce no smoke, then the flame is weak and deficient. But Argand gave a real prac- 
 tical use to his invention by applying the happy idea of an artificial draught. The principle is the same 
 as that of chimneys : a rest on the outside of the burner supports a straight glass cylinder, which, in- 
 cluding the inner and outer draught of air, exerts a powerful influence upon the velocity of both, in 
 proportion to its height. With this arrangement, the point at which smoke begins to be evolved cor- 
 responds with a much higher intensity of flame. Another advantage, not at first anticipated, is the 
 great steadiness caused by the chimney. When a draught of air comes in contact with an unprotected 
 flame its force and cooling influence produce diminished combustion, and at the same time flickering and 
 smoke ; in Argand’s burner, on the contrary, the supply of air to the flame is become self-dependent, 
 whilst the heat itself is made the motive power. The cylinder protects it from any direct interruption, 
 and that arising from the draught apertures is hardly felt at all in the interior. It must not be left 
 unnoticed that the straight Argand cylinders, whilst assisting the draught, fall into an opposite 
 extreme, and supply too large and injurious an amount of air. This was remedied, soon after 
 the original invention, by Lange, and forms an important improvement ; it consists in contract- 
 ing the diameter of the glass chimney at a certain height above the burner at b, thus forming 
 a shoulder of a few lines in width, as in Figs. 2478 and 2479. The draught, moving in the 
 simple cylinder, in a parallel direction to the axis of the cylinder, is thus broken at the 
 shoulder, and thrown into the flame at a certain angle. The supply of air is, therefore, 
 lessened, but the direction given to it is preferable ; and that part of the current, which, with- 
 out taking part in the combustion, cooled the flame in a useless manner, and passed along 
 the inner surface of the cylinder, is almost entirely removed. The glass chimneys are, how- 
 ever, applicable to all burners with flat, round, or semicircular wicks. 
 
 Sinumbra lamp . — When the astral lamp is used as a hanging lamp, the shadow of the circular oil 
 vessel i3 thrown more towards the ceiling ; this is not the case when it stands in an upright position, 
 
 2470. 
 
 ff\ 
 
 
 \ 
 
 By an ingenious modification, Phillips has succeeded in his sinumbra lamp, Figs. 2480 and 2481, (sim 
 umbra,) in rendering the shadow imperceptible even in the latter kind, and this is done by the peculiai 
 
168 
 
 LAMPS. 
 
 section of the circular vessel o. Its three surfaces meet in the form of a flat wedge, the sharp edge of 
 which is directed towards the flame. The position of the flame, in relation to the oil vessel is such that 
 Dwo tangents drawn from the apex and base of the flame to the latter, meet a few inches behind it in x. 
 Beyond this the vessel can cast no shadow ; but even in this small space it is almost entirely destroyed 
 cy a vase-shaped ground-glass shade, which, resting upon the oil vessel, surrounds the chimney, and 
 scatters the light in all directions around. The manner in which the wick is moved in the sinumbra 
 burner is original, and deserves notice ; there is neither screw nor toothed rod employed. The inner 
 cylinder f is furnished on its outer surface with a deep, much inclined spiral groove, into which the 
 short peg or appendage a of the wick-holder e tits. If, therefore, the latter is turned on its axis, the 
 peg moves along the groove and forces e up or down. From its position in the burner, however, e 
 cannot be approached by the fingers, and directly turned ; this is effected by the cylinder d, whicn, 
 throughout its whole length — that of the burner — has a slit, into which a second peg b, on the outer side 
 of e, tits. By this arrangement d can at any time be freely moved up or down, but cannot be turned 
 without taking with it the wick-holder, causing this either to be raised or depressed. In order that d 
 may be moved easily, and without danger from the flame, it is firmly connected with the support for 
 the chimney, terminating above in a thick ring, two or three lines wide, which rests upon the edge of 
 the cylinder c , this being purposely made lower, and the whole is thus brought up to the full height of 
 the burner. In this ring the supports for the chimney are fixed. If these are turned with the hand, d 
 is turned at the same time, and with it the wick-holder, which is thus moved up or down. Great 
 mobility characterizes this arrangement, and no forcing or compression of the ring holding the wick can 
 occur. 
 
 2 t 82 . 
 
 All the lamps as yet described are subject to one common evil, that of having the oil vessel, at all 
 events, within a few lines of the level of the burner ; in a position, therefore, which throws the most 
 objectionable shadow. A whole series e ‘ contrivances have consequently resulted from the efforts of 
 inventors to transpose this cistern either a considerable distance above the flame — when its shadow 
 would fall upon the ceiling of the room — or to a position much below the flame, when it would fall at 
 the foot of the lamp. Both resources, however, when applied, give rise to new and critical difficulties ; 
 the former requires that the supply of oil which flows downwards to the burner, should be accurately 
 regulated. The most common and general application of this method is that adopted in the standing 
 lamp, Fig. 2482. The oil cistern A is a movable metallic vessel, capable of being closed at the bottom 
 by a valve a, which moyes between the regulating rods b b. In the upright position the valve falls 
 back and leaves the aperture open for filling the vessel ; if the valve is then pulled up by its rod, the 
 aperture is closed, and the bottle can be inverted and put in its place in the case B, (as in the figure.; 
 it is no sooner there than an alteration occurs. The rod attached to the valve is, namely, so long that 
 
LAMPS. 
 
 16 « 
 
 the valve is raised as soon as it touches the bottom of the case d. The oil, therefore, flows out for a 
 few seconds until it lias risen so high in the case as to stop the aperture of the bottle A. From this 
 instant equilibrium is established, and as the mouth of A is on a level with the height of the burner, 
 this becomes filled at the same moment, connection having been made by means of the tube g. The 
 lamp has really two oil cisterns — an under one, which directly feeds the burner, and an upper one, the 
 inverted bottle, for the supply of the lower as the oil is gradually consumed. As long as the level of 
 the oil in B remains unchanged, and the mouth of A consequently closed, no air can enter A, and the 
 whole stock of oil is kept up by the pressure of the atmosphere. When the lamp has been lighted 
 some time, and the oil sinks below the mouth of the bottle, a few air -bubbles enter and take the place 
 of an equal bulk of oil, which flowing out, raises the level in B until the mouth is again closed. The 
 same operation is repeated as long as the oil is present in A. 
 
 The other parts of the lamp are easily understood : f is the support for the cylinder, (the peculiar 
 form of which will be explained below,) q is the vessel for the toothed rod, ar.d e is an aperture in the 
 case for the easy admission of air into the interior. 
 
 On reflection it will be immediately perceived that in all similar lamps, from the peculiar arrange- 
 ment of the oil cistern, the height of the oil in the burner will not be always quite constant, but will 
 alternately sink and immediately rise again to its former height, whilst in the lamps previously 
 described, the suction of the wick is rendered more and more difficult by the constant sinking of the 
 level of the oil. 
 
 The principle in question has been put into practice with better success by means of a simple vessel 
 without case, as for instance, that represented in Fig. 2483. The mouth of the movable oil bottle cor- 
 responds here with the lower opening b of the tube a b, which passing through the air-tight collar x, is 
 movable in the lid of A. The oil consumed in the burner e is replaced from the stock contained (above 
 the level n n ) in A, the place of which is then occupied by air, which enters at b. As soon as the con- 
 sumption of oil in eb ceases, no more air- bubbles enter, and vice versa. As the level of the oil in the 
 burner is dependent upon the position of the mouth b , this can be most accurately adapted to circum- 
 stances, a b being movable. The cocks o and o' are only used in filling the vessel. 
 
 This principle can be applied in the same manner, or in a much more compact form to lamps with 
 circular oil vessels, by means of Caron’s stop-cock, Fig. 2484. The conical plug of the cock is com- 
 pletely hollow, and at a certain distance from the middle it is supplied with a cross bottom a, dividing 
 the space into two unequal parts. In the upper part the round lateral aperture e is made opposite to o 
 in the lower part ; e' and o' are the corresponding apertures in the case. In the position represented in 
 the drawing, e is closed, whilst o is in free communication with the stock of oil in the. circular vessel A A. 
 This stock comprises the whole quantity, situated above the mouth m of the tube in n, corresponding 
 with the tube a b of Fig. 2483. The side tube comrftunicating with the burner also opens into q q. In 
 the opposite position of the cock (by closing o) the space A, and, in the first instance, q q is shut off 
 from communicating with the burner, whilst the same space A can then be filled, e being open. 
 
 By transposing the oil cistern to the foot of the lamp, by which means all shadow is avoided, we 
 forego the important advantage which the free flow (fall) of oil occasions, and by means of which it can 
 easily be conducted to the burner ; and, as consumption goes on, the oil must then be raised. The 
 lamps made upon this principle are interesting on account of the ingenious, but at the same time very 
 complicates elevating apparatus, which partly depends upon hydrodynamic, partly upon hydrostatic 
 laws, and is partly also a mere mechanical arrangement. 
 
 Girard's lamp . — Girard’s (hydrostatic) lamp is constructed upon precisely the same principles as the 
 air-chamber of a fire-engine, or resembles rather Hero’s fountain, Fig. 2485. In these arrangements it 
 is well known that the pressure exerted in a vessel is transferred to any other distant cistern by means 
 of compressed air, and is the means of forcing a liquid from its previous position, for example, in an up- 
 ward direction. In Hero’s fountain the primary pressure is produced by the column of water a fed 
 from the vessel above it ; the air inclosed between c and the lower bulb is thus compressed, acts upon 
 the surface of the fluid in c, and forces it to a corresponding height in d. All these compartments are 
 also present in Girard’s lamp, but are closely packed together for the sake of saving space, as is seen 
 by the sketch, Fig. 2486, where the unimportant parts are left out. A is the reservoir for the forcing 
 column of oil in the tube a b. B the lower vessel with the inclosed air B', which conveys the pressure 
 received from a b through cd‘ d to the vessel C, and in the first instance to the air C' contained in it. 
 As long, therefore, as there is pressure from a b, the air C' will cause the oil in C to rise in the tube g h 
 to a corresponding height, (to the burner.) This height, therefore, depends upon the uniformity of 
 pressure in general, and ultimately upon the constant uniformity of height in the column of oil a b, which 
 lias a tendency every moment to shorten the play of the whole, both from above and below ; from 
 above by the sinking of the oil in A, from below by its rise in B. To avoid the former, at least for the 
 duration of an evening's consumption, the vessel A is furnished with a tube ef upon the same principle 
 as that described in the oil cistern at Fig. 2483, so that th i height of the column of oil exerting pressure 
 
170 
 
 LAMPS. 
 
 coincides with the aperture e, and all the oil above that must be considered as a store for the supply o' 
 that column. The latter is obviated by the narrow vessel v which surrounds the aperture b, and is 
 filled up to s s in a few moments by the oil flowing from A, thus constituting a basis of uniform height 
 for the column. Both contrivances are effective until the oil in A sinks below e, and has risen on the 
 outside of v above the level s s in B. With the requisite height of the lamps the pressure of the column 
 would raise the oil to a greater height than is desirable. To avoid an excessive length of burner, the 
 tube c d' d may be curved like a siphon, as indeed was done by Girard, by which means the oil in ef is 
 caused to rise as much less as d is below the fluid level in C, therefore x less. The pressure is first 
 exerted to overcome the column of oil x, and it is only the excess that exerts an upward influence in g li\ 
 the result is, therefore, the same as if the elevation in g li was effected, not from the level of the oil at 
 C, but at g, for gh — ess. 
 
 Future endeavors to bring the principle of Girard’s lamp into a form more suited to daily use will, 
 perhaps, be successful ; for the limited application which has been made of it must be ascribed to its 
 inconvenient shape. The following points deserve particular notice ; first, as is obvious enough, the 
 working of the lamp is not independent of the changes of temperature and pressure in the atmosphere. 
 Increasing pressure (rise of the barometer) and a lower temperature will diminish the bulk of the air 
 inclosed in B and C, and cause an augmented flow of oil from A towards B. A fall in the barometer, 
 and a higher temperature, will produce an opposite effect, and cause the oil to flow from the burner. 
 The effect of temperature is the stronger of the two ; but both by proper means can be rendered imper- 
 ceptible, at least for the duration of an evening. Another and a greater objection arises from the posi- 
 tion and the shape of the vessel 0, upon which, as may be seen by the sketch, the supply of the burner 
 is solely dependent, whilst the oil of A and B is only employed as a fluid pressure. C cannot well be 
 made deeper without increasing immoderately the height of the lamp ; there is, therefore, no other 
 means of affording space for the requisite quantity of oil for an evening’s consumption, than by adding 
 to the breadth of this vessel. When this is done, and from its being placed immediately under the 
 burner, the shadow falling between o ?/ and o z will very much exceed the space occupied by the foot ot 
 the lamp. Lastly, the necessary additions and apparatus for filling the lamp deprive it of that ease 
 and simplicity in the management which daily use justly demands. 
 
 248G. 
 
 2488. 
 
 The hydrostatic lamp . — The doctrine of the equilibrium of fluid pressure has found an application in 
 the hydrostatic lamps. Two different fluids, brought into tubes which are connected at the bottom, will 
 balance each other at different heights, according to their respective densities. The one fluid will form 
 a column as many times lower as its density exceeds that of the other fluid. A column of mercury 
 requires to be only one inch in height to balance a column of sulphuric ether of 19 inches, or a column 
 of oil of 14 inches. 
 
 After salt and water, syrup, honey, mercury, had all been tried as heavy liquids, Thilorier succeeded 
 m 1825, at Paris, in giving a decided pre-eminence to his lamp by the use of a solution of white vitriol 
 (sulphate of zinc) anil by a suitable apparatus. When we consider that the fluid producing the pressure 
 must not affect the oil or the sides of the vessel, (tinned iron,) that it must not become solid (crystallize) at 
 
LAMPS. 
 
 171 
 
 2489. 
 
 a temperature several degrees below 0° C., that it must be cheap, and have the proper density, we 
 shall then understand how to appreciate the discrimination which led Thilorier to employ a solution of 
 equal parts, white vitriol and water. Such a solution is 157 times denser than oil, so that a solution of 
 zinc 10 inches high can support a column of oil 15'7 inches in height. 
 
 It is obvious that, with the diminution of the column of oil (the consumption of oil in the burner) the 
 solution of zinc will sink to a corresponding level, and will only be enabled to force the oil to the origi- 
 nal height, when it itself is fed by a reservoir of zinc solution. The cistern A in the section of the lamp, 
 Fig. 2487, is solely for this purpose. In a chamber B, in the foot of the lamp, both the equally poised 
 columns terminate, namely, the column of oil in the tube a b, which terminates above in the burner, and 
 the column of zinc solution in e d, above which the cistern A is situated containing the zinc solution. 
 The flow is effected in the manner described in Fig. 2483, by means of the tube o P, through which the 
 external air enters bubble by bubble, as the solution in e d threatens to sink. The height of the column 
 must, therefore, be reckoned from P ; B is completely filled, and by both fluids at the same time, so that 
 no air remains in it. Into the lower solution of zinc (extending to nn 
 in the figure) the tube ed is plunged; into the oil above, on the con- 
 trary, the tube a b does not enter beyond the top layer of the fluid in B. 
 
 From the time of lighting and during the combustion, the level nn 
 naturally becomes higher and higher. At length B becomes quite filled 
 with solution of zinc, and oil must be supplied. This is done by a 
 separate funnel through the burner, which obliges the solution of zinc to 
 return to its former position, an outlet being afforded for the air in A. 
 
 The tube o P, Fig. 2488, (twice its proper size,) is intended for this 
 purpose, having a conical appendage h accurately ground to fit into//, 
 and luted into the lid of A. The position represented is that for filling, 
 and this is effected by the peg g, which is fixed to o P, and only rests 
 on the edge of //; when h is to be closed the tube is turned until g 
 falls into a perpendicular cavity. The oil which overflows the burner 
 in filling, and at other times, collects in the concave lid of A, and passes 
 off by i i to a ring-shaped movable vessel q. This vessel is open and 
 ring-shaped, to admit of the passage of a b and e d through the middle 
 of it. 
 
 It must not be supposed, even when every thing goes on regularly, 
 and the supply in A is not exhausted, that the level of the oil in the 
 burner always remains the same, for the column nab is constantly 
 shortened by the rise in n n, and more rapidly than is the case with the 
 zinc column n P during the same time. The inventor has succeeded in 
 rendering this imperceptible for a duration of six hours, by making the 
 diameter of B very large in proportion to that of a b. The difference of 
 level does not actually exceed two to three lines, whilst the oil in the 
 burners of astral and sinumbra lamps frequently falls one inch. 
 
 Pump lamps . — The general conclusion may be inferred from what 
 has been said, that the different static lamps either do not attain the 
 important advantages which their construction was intended to confer, 
 or are accompanied with corresponding disadvantages. In contradis- 
 tinction to these we have the lamps with a mechanical arrangement for 
 raising the oil ; and as a pump is generally employed for that purpose, 
 they are called pump lamps. 
 
 The simplest example of these is the pump lamp with a flat wick, 
 very much used in the south of France, although not in this country ; 
 the motion of the pump is produced by the hand, but in a very imper- 
 fect manner. The piston of the pump is kept constantly raised by the 
 tension of a spiral spring. As soon as the piston-rod, which is also the 
 ascending tube and in firm connection with the burner, is forced down, 
 by overcoming the power of the spring, the descending piston forces the 
 oil in the cylinder to rise through the tube to the burner. When the 
 stroke is ended, the elasticity of the spring brings the piston to its 
 former position, and the cylinder becomes again filled. As candles re- 
 quire snuffing from time to time, so here, the pump must be used at 
 6hort intervals. In lamps of this kind, with double draught, the burner 
 is fixed, but then there is a piston-rod with a handle at the side of the 
 ascending tube. The uniform working of such a lamp depends, there- 
 fore, upon the care which is taken to supply the oil that is consumed by 
 repeated use of the pump. If this is only done at long intervals, the 
 flame will vary from its utmost intensity to a very dingy fight. 
 
 The numerous improvements which have here been noticed, with 
 reference to the most successful and interesting inventions, must be con- 
 sidered as important advances; but they have nevertheless left one 
 point out of view, upon which the most indispensable conditions for 
 combining a perfect, and at all times, uniform evolution of fight depend; 
 a point which is indisputably the most difficult of all to accomplish. It 
 has been noticed how the lowering of the oil level obstructs more and 
 
 more the functions of the wick, and consequently diminishes in an «qual degree the brilliancy of the 
 flame. The lamps with a supply, upon the principle of connected tubes, are subject to this evil in its 
 
172 
 
 LAMPS. 
 
 entire extent; those with an inverted bottle or similar arrangement are also influenced by it within 
 certain limits. In the former the brilliancy rapidly diminishes ; in the latter it becomes lessened, and 
 returns to its original state at regular intervals. 
 
 Carcel’ s clock-work or mechanical lamp. — Carcel, in the year 1800, was the first to carry out the idea 
 of pumping up the oil from the foot of the lamp to the wicK, by simple machinery like that of clocks, 
 and, moreover, in such quantity as to exceed the quantity consumed during the whole period of burn- 
 ing. The invention of his clock-lamp is without precedent, with reference to the uninterrupted and 
 perfect supply of oil to the wick. Whilst in the other lamps the burner contains a stationary column 
 of oil, which either constantly decreases from above or is reinstated from time to time, the oil in Car- 
 cel’s burner forms a constant ascending current, which always supplies the wick with as much as it can 
 possibly require ; and lastly, the unconsumed portion flows back to the foot over the outside of the 
 
 Carcel’s invention left only unimportant points connected with the works and the pump to his suc- 
 cessors, to which the skill of others has been applied. Figs. 2489 and 2490 present a section of Carcel’* 
 lamp and its various parts, with Penot’s improvements. The chief parts of the lamp are arranged as 
 follows : The case for the works B and the space A for the stock of oil, form the foot of the lamp. The 
 stem of the column contains only the ascending tube b , which separates above (over the capital) into a 
 forked appendage, (crutch,) upon which rests the burner with its two concentric tubes ee The burner 
 
LAMPS. 
 
 17S 
 
 and the ascending tube form, therefore, a space which is connected with A by means of tire pump. This 
 latter is a so-called priest-pump , and is more simply represented in Fig. 2491. The space x is closed 
 at the top by a piece of elastic cloth or leather, in the middle of which, when [S1 2491. 
 it is considered as a piston, the piston-rod is fixed. By its upward and down- 
 ward motion, an alternate expansion and contraction of x is effected. In the 
 first case the valve s opens, and oil enters a: from rr; in the other case, 
 through the valve s', oil passes from x, and is raised in the tube t. The 
 motion of the cloth or leather acts in short in the manner of the cheeks and 
 muscles in drinking and blowing. To meet the unavoidable obstructions 
 which would result from the presence of impurities in the oil, it is all made 
 to pass, whilst still in A and before entering the pumps, through a metallic 
 sieve with fine holes </, which surrounds the whole of the front part, including 
 the entrances to the valves below. 
 
 The quadrangular box of the pump contains, for preserving uniformity of 
 action, three simple priest-pumps ccc, made of gold-beater’s skin, which, during every moment they are in 
 action, alter their positions relative to each other. This necessary circumstance is self-evident from the 
 whole arrangement of the pump. Each single pump has two valves, an entrance valve (the under one in 
 the figure) and an exit valve (the upper.) a is a separate chamber for each : the space for receiving the oil 
 above the exit valve, on the contrary, is common to all. The three short piston-rods, if they may be so 
 called, work upon three crooked arms B y x on the same axis, but in different directions. One pump 
 must, therefore, always be forcing, whilst the second is sucking, and the other midway between the two. 
 Below, or in the direction of B, the chamber A is completely closed, with the exception of a stuffing-box, 
 through which the crooked pin of the axle is moved. The wheel t passes under a box placed at the 
 side, in which this stuffing-box is situated. The iron frame i i serves to give steadiness to the works in 
 B ; the most important parts of the arrangement may be seen in Fig. 2490. Motion is obtained by the 
 spring wound up in the case ooo, which is furnished with cogs. The cogs of o o o first move the 
 toothed wheel t upon the same axis by means of x. The wheel t catches the second cog y above, which 
 has the same axis as the piston-rods, and thus the pumps are set in motion. Below, however, t moves 
 the endless screw, on the axis of which is the fly-wheel d for regulating the works, by means of z, and 
 the toothed wheel u and v. At the very bottom, on one side of the foot of the lamp, is a small bolt, 
 which, when pushed forward, catches the fly-wheel, and either stops the works, when in motion, or sets 
 them going when it is pulled back, and the whole has been wound up. 
 
 The stopping-wheel W is used for winding up the machine with a key. 
 
 The toothed rod g, with the wick-holder, works below the crutch of the ascending tube, in the 
 case /. 
 
 Experience has shown that the whole arrangement of the works is not so tender and brittle as might 
 at first sight have been supposed. 
 
 The overflow of oil from the burner makes it necessary to screw the wick up somewhat higher than 
 in common lamps ; and this brings with it the great advantage of the flame being more raised above 
 the edge of the burner, where less heat is conducted from it, and it burns more perfectly, producing no 
 carbonaceous matter on the wick and about the edge of the burner, which, in general, so materially 
 interferes with the regular flow of oil. 
 
 Carcel’s lamp would, without exaggeration, have been prized as much as Argand’s had been six- 
 teen years previously, if a less expensive and more suitable form for general use could have been given 
 to it. 
 
 At an earlier period, and again more recently, the idea has occurred to those versed in these 
 matters, to replace the complicated clock-work, either by the force of a falling body, (for instance, a 
 piston in a cylinder,) or, at least, to cause the tense spring to act upon a larger piston of that 
 kind. In both cases the oil is contained in a lamp-like vessel, resembling the cylinder of a pump, 
 from whence it is slowly forced upwards by the piston (moved either by gravity, or a spring) to the 
 burner. 
 
 So far, all is simple and easy ; but the practical use of the lamps has always foundered on the diffi- 
 culty of regulating the acceleration of the fall, or the diminution of the force of the spring, to the 
 uniform demand of the burner. The arrangements of this kind are all wanting in simplicity, or they 
 effect their purpose but imperfectly. ‘•Generally, the ascending tube is contracted conically at a certain 
 spot, into which a conical plug fits. The spring in rising enlarges the aperture at the contracted' spot, 
 whilst the sinking piston lessens it, by forcing the plug either backwards or forwards, in proportion as 
 their motion is irregular. 
 
 The application of a phenomenon for raising the oil in lamps, first proposed by Celarier, is worthy of 
 notice, from its novelty and simplicity, and because it may possibly be productive of something else, 
 not from the use actually made of it at present, which is by no means established. It is of very com- 
 mon occurrence, and may easily be observed. Celarier’s lamp consists principally of two vessels, fixed 
 one above the other, which are separated from each other by a partition ; the upper contains oil, the 
 lower air. In the partition, a narrow tube is placed, which opens into the air-chamber below by a 
 valve, and somewhat higher in the oil vessel with a simple aperture. On filling the lamp, the oil in 
 this tube rises to the same height as in the vessel ; but as soon as the valve is opened, the air begins 
 to escape by the same tube as that through which the oil is passing, in endeavoring to fill the lower 
 vessel. The result is — with such a narrow tube — that with the bubbles of air, drops of oil, or rather 
 little columns of oil, are carried up much above the level of the oil. Another plan, applied by Samuel 
 Parker and Mallet, in which the oil is warmed in a ring-shaped vessel above the flame, before reaching 
 the burner, promises theoretically to be of value, but requires to be subjected to further proof. 
 
 Ludersdorff’s lamp. — In Berlin, the prices admit of using instead of pure oil of turpentine (that is, the 
 lighting material of Liidersdorff) a mixture of this spirit with 4 parts of strong alcohol, of at least 90 
 
174 
 
 LAMPS. 
 
 per cent. (This is the camphene in use with us.) This strength is necessary ; for, with a greater amount 
 of water the flame would b® too much cooled, and the oil of turpentine be imperfectly held in solution. 
 The carbon, originally amounting to 88 per cent., or 8 times the quantity of hydrogen, is diminished by 
 this mixture (illuminating spirit) to 63 per cent.., or three times the hydrogen, which is much less than is 
 contained in oil or tallow. The lesser evolution of light, from the same weight of spirit, is, however, 
 actually compensated, although at some cost, by the greater rapidity with which the light is evolved 
 from the same quantity. Ludersdorft’s lamp, Fig. 24914, is well adapted to show the different mode 
 adopted in burning the volatile oils, from that employed with the fats. 
 
 A is the vase for the illuminating spirit, into which the burner 11 descends from above almost to the 
 bottom. It consists first of a straight, pretty wide metal tube a a, fitting tightly into the real burner-tube 
 ti u, which surrounds a loose cotton wick o o, and fastens it by the semicircular piece x. Above A, at 
 
 24911 . 
 
 a distance of about two inches, (the wick extending thus far,) the tube becomes narrower, and ends at 
 d, in the knob c, which is the real burner ; at the base of b, from ten to twelve holes, \ line in bore, are 
 made in a circle at equal distances from each other. When the lamp is to be used, common spirits ol 
 wine is ignited in the cup e e, to vaporize the illuminating spirit in the upper part of the wick. As 
 soon as the vapor issues from the apertures b, it is ignited, and forms the flames/, which surround the 
 knob c. The metallic mass is then sufficient, on account of its high temperature, to keep up vaporiza- 
 tion with ease, (even at the distance of c from the wick,) and the lamp continues to burn by itself. To 
 protect A from the action of the burner, which gradually becomes heated, the latter is suivounded, to 
 the depth of three inches, with a wide case i i, which is attached to it below, (at i i,) so that a space 
 filled with air surrounds it thus far. Lamps of this kind give a costly but brilliant light, free from all 
 the inconveniences of common wicks. 
 
 The Liverpool burner . — The original Argand burner g, Fig. 2492, is supplied with oil by the tube i. 
 At its lower aperture a wire b is fastened, which rises through the axis of the burner to a few lines 
 above its upper margin, where the projecting end is furnished with a screw. This is intended to sup- 
 port a round copper plate a (in the shape of a button) of equal diameter with the wick. It is difficult, 
 at first, to establish the proper relation of distance between a and the margin of the burner, but it is 
 easily found, experimentally, by screwing the plate backwards and forwards. As the result of this 
 arrangement, the internal draught is forced from its original perpendicular direction, and broken against 
 the plate a, whence it is propelled at a sharp angle, nearly horizontally, against the flame, which thus 
 assumes a globular, instead of its ordinary cylindrical form, and (as is shown in the figure) is forced into 
 contact with the external current. The form of the flame makes it necessary to have the peculiar bulg- 
 ing chimney c, and this is supported by the case e of the burner. Complete combustion, together with 
 
LAMPS. 
 
 175 
 
 intense brilliancy and whiteness, characterizes the flame • but there is nevertheless a certain want of 
 uniformity, which, however, does not exist in the nature of the principle, and can be avoided by a 
 proper regulation of the draught. 
 
 The lamps constructed by Benkler and Buhl, in Wiesbaden, since the year 1840, depend entirely 
 upon the same principle, causing the draught to impinge at an angle upon the flame. The apparent 
 novelty of the invention, the surprising brilliancy and peculiarity of the flame, and partly the solid and 
 elegant workmanship of the lamps themselves, led the public, at least for a time, to confound these 
 advantages with the more essential one, namely, the economical consumption of the oil, and created in 
 a short time an enormous demand for this invention. Some hasty experiments, which were published, 
 tended very much to augment this over-estimation of its value. 
 
 Fig. 2493 is a sketch of the general plan of Benkler’s burner. Fig. 2494 is the ground plan ; and 
 Fig. 2495 represents the upper distinct parts. The shoulder of the chimney is here formed at the junc- 
 tion of two pieces; a narrower glass b, above the flame, and a wider glass a, which is below it. Just 
 at this junction is placed the most important part of the arrangement, which consists of a conical 
 
 ascending brass ring d d, with an aperture of the same diameter as the wick. This flat, open cone is 
 immovably fixed to the upper glass b, by bending up its outer edge, Fig. 2495. The connection of b 
 with a is effected by a so-called bayonet joint. For this purpose, on the lower margin of the plate d, 
 there are two tongues e, and these correspond with two cuts in the ring c, with which the margiu of a 
 is encircled. When, therefore, d is so placed upon a that the tongues and cuts correspond, a simple 
 turn of d is sufficient to bring the tongues under the ring c, and thus secure the whole. The apertures 
 oo are made around a, to increase the draught from without. The principal addition, therefore, in 
 Benkler’s lamp is a sudden contraction in the chimney at a certain distance from the flame, the aper- 
 ture being of the same diameter as the wick, and this is produced by the insertion of a metallic ring, or 
 cone. 
 
 The action of such a contrivance is easily understood. The external and internal currents of air and 
 the flame must pass through the aperture of d, where a rapid contraction results. The outer current is 
 driven against the axis of the flame at a sharp angle, and thus forces the flame itself into the inner cur- 
 rent, so that an intimate mixture of air is effected with the products of decomposition of the oil. The 
 flame becomes narrower, and three times as long, when, by keeping back all the air which has no part 
 in the combustion, and by giving a proper direction to that which has, the highest and whitest bril- 
 liancy, and considerable evolution of heat, is attained. A perfectly white heat is produced ; for, in 
 consequence of the well-ordered combustion, the suspended particles of carbon are more intensely heat- 
 ed than in any other lamp. Notwithstanding the intensity of the heat, the chimneys — in corroboration 
 of what was stated above — stand well. A very short portion of the flame, that which produces the 
 least light, is naturally situated below the cone d ; but the longer portion, the essentially luminous 
 
 2493. 
 
 
 2494. 
 
176 
 
 LAMPS. 
 
 part, is above, and throws a shadow from d downwards, which is perceptible in standing and hanging 
 lamps, but is of no moment in the determination of the intensity of light, as it only occurs in the direc- 
 tion of the edges of d. As the cone d has no other object than that of producing a sudden contraction, 
 chimneys are now made in one piece with an inward bend in the proper place. 
 
 The lamps constructed by Benkler and Ruhl are on the principle just described, and have been car- 
 ried out in this country under the name of Solar Lamps. The main point in the peculiar construction 
 of these lamps, is the manner in which the air is caused to impinge upon the flame by the adaptation 
 of a metallic or glass cone, represented at a in the figures below. The introduction of air at this par- 
 ticular part of the flame, or at this certain angle, admits of crude cheap oil being consumed in the 
 lamps, which would produce smoke if burnt in lamps of the ordinary construction. The combustion of 
 this oil in the ordinary manner being attended by an evolution of smoke and smell, indicating an im- 
 perfect consumption of the constituents of the oil, gives rise to the necessity for an increased supply of 
 oxygen or air to that particular part of the flame where these unconsumed portions are evolved, to 
 produce the inodorous and invisible products which alone should result from perfect combustion. The 
 oil in the solar lamp is contained in an annular vessel, similar to that described at Fig. 2478, and the 
 lamps are constructed in precisely the same manner, with the exception only of the burner. The first 
 form in which the new burner was introduced is represented in section at 1, Fig. 2496, and consists of 
 a solid metallic box fixed upon the circular wick-holder of ordinary construction, so that the cone or 
 
 contracted aperture a , shall be bare fth of an inch above the top of the wick-holder. This relative posi- 
 tion is observed in all the burners. This form of cone box was found very inconvenient, by becoming 
 exceedingly hot and throwing a considerable shadow, it was consequently soon superseded by that 
 represented at 2, Fig. 2496, in which the metallic box is very much diminished in size, and the cone is 
 composed of glass, with a small ring of metal round the mouth a. This ring of metal is essential, as it 
 is necessary that the aperture should be always of the same diameter, and glass cones can never be 
 made with sufficient nicety to present at all times an exactly similar mouth. The solid box was sub- 
 sequently replaced by the open skeleton cone holder represented at 3, Fig. 2496, called the screw cone 
 glass-holder, in consequence of the tall thin chimney being screwed on to the top of the holder. The 
 last improvement is the plate cone glass-holder represented at 4, Fig. 2496, in which the metallic cone 
 is replaced by a flat metallic ring fixed upon a skeleton support, the external edge of which fits closely 
 to the glass chimney. 
 
 In the last form of burner, little or no external current impinges upon the flame from the outer sides 
 of the cone or its substitute ; but the flame is only forced inwards so as to come more completely into 
 contact with the current of air passing through the interior of the burner. The solar lamp has been 
 extensively used in consequence of the low price of the oil which it consumes ; it requires, however, a 
 good deal of care and cleanliness in trimming, the wick must be freshly cut every time the lamp is 
 used, and the reservoir should be refilled with oiL 
 
LAMPS. 
 
 177 
 
 2497. 
 
 A form of pressure lamp, called the Elliptic lamp, in which the constant flow of oil to 
 regulated in an ingenious manner, has been patented, and is found to answer perfectly, 
 crude vegetable oils are consumed in it. Fig. 2497 represents 
 an entire section of the lamp. The foot of the lamp forms at the 
 same time the oil cistern : it is of a cylindrical shape, and a 
 leather piston or valve B, is worked up and down in it by rack 
 and pinion seen at L. F is a spiral spring of strong iron wire fixed 
 at the top to the solid stem of the lamp, and exerting a constant 
 pressure on the piston, so long as it is in any position above the 
 bottom of the oil cistern. The tube D, which opens at the bot- 
 tom in the shape of an inverted funnel, and ends in a disk pierced 
 with holes, supplies the oil to the burner and passes in an afr- 
 tight manner through a stuffing-box in the piston B, and can thus 
 be moved with ease, the piston remaining stationary. This tube 
 D, is widened above on approaching the burner, and receives a 
 fine silver tube several inches long, and one-thirtieth of an inch 
 internal diameter, which is surrounded by a cap of gauze, made 
 of copper wire tinned, to prevent corrosion. This gauze has very 
 small meshes, that no solid particles mechanically mixed with 
 the oil may be carried up into the silver tube, and thus impede 
 or altogether stop the passage of the oil. The whole of the oil 
 must pass through the silver tube before reaching the burner, 
 and the friction thus exerted against the sides of the narrow 
 tube is the only resistance offered to the oil, which would other- 
 wise be forced up all at once to the burner by the pressure of 
 the spiral spring. This, therefore, is the regulator for the supply 
 of oil, and must be so proportioned in length and bore to the 
 force of the spring, as to admit of a constant excess of oil flowing 
 to the wick and over the sides of the burner, where it is caught 
 in a receptacle and carried back into the oil vessel at the foot of 
 the lamp. The lamp is filled with oil by slightly raising the 
 whole interior portion from L, and pouring oil through the stem 
 to the cistern below ; the oil then rests in the first instance on 
 the top of the piston. The whole interior portion of the lamp is 
 then wound up by the key I K and the rack- work L, until the top 
 of the cistern prevents the piston B from ascending higher. The 
 tube D and the burner, <fcc., attached to it is then pushed down by 
 the hand through the stuffing-box until it attains its original po- 
 sition. The oil which was previously above, having passed 
 
 2498 . 
 
 the wick ia 
 even when 
 
 PlMinu UAtini'c / i uS^/jr' *'‘ U " “***'■' 
 
 during the ascent of the piston between it and the sides of the cylinder, is now below the piston, and 
 the spring in forcing the latter down will tend to force the oil out through the tube D to the burner. 
 The force of the spring and the resistance offered by the silver tube are so proportioned that the sup- 
 ply of oil shall last eight or ten hours. 
 
 The thick consistence of crude whale oil offers such powerful resistance to the action of capillarity 
 at the ordinary temperature of the air, that the oil cannot be burned in common lamps, unless it is 
 previously rendered more fluid by the aid of heat. To effect this a very ingenious form of lamp has 
 been introduced, called the Economic, or hot- oil lamp. The oil reservoir of this lamp, Fig. 2498, is 
 composed of a double cylinder surrounding the upper part of the chimney, which is constructed of 
 
178 
 
 LAMPS. 
 
 metal and slightly curved outwards, so as to reverberate the heat upon the oil vessel, and heat the oil 
 to a considerable extent. The hot oil then descends by the arm to the burner, as shown in the figure. 
 The lower part of the arm, which is attached to the oil vessel, is furnished with a slide valve worked 
 by the trigger, so that the supply of oil can be cut off by raising the trigger, and the oil vessel entirely 
 removed from the lamp for the purpose of filling, &c. The oil is introduced by this valve, the oil cis- 
 tern being inverted, and this should be refilled each time the lamp is used, care being taken that no air 
 remains in the vessel, as this would be expanded very much by the heat, and cause the oil to overflow 
 The flame is regulated by raising or lowering the bell-mouthed glass chimney, which rests upon three 
 points below and is moved by rack and pinion. The wick is not movable, as is the case in ordinary 
 lamps, and a fresh wick, which is accurately cut by machinery expressly for this lamp, must be insert- 
 ed every time the lamp is used. A paper or glass shade surrounds the whole of the upper part of the 
 lamp, according as the light is required to be thrown downwards or uniformly diffused through the 
 apartment. Dr. Ure has reported the illuminating power of this lamp to be superior to that of Carcel’s 
 mechanical lamp, and when consuming southern whale oil, it would appear from his statements to 
 deserve the appellation of the “ Economic” to the full extent of the word. 
 
 Camphene lamps . — It is only within the last few years that oil of turpentine or camphene has been 
 successfully introduced into general use as a source of illumination ; and it is by applying the principle 
 of the solar cone in an extended manner that this highly carbonaceous substance can be completely and 
 conveniently consumed. The pure oil is clear, colorless, and very mobile ; it has a peculiar smell and a 
 burning taste. Its specific gravity is 0 86 to 0-87. The commercial oil is frequently adulterated with 
 resin, which raises the specific gravity, and which increases in quantity when the oil is exposed, in con- 
 sequence of the absorption of oxygen from the air. When pure, the oil boils at 312°, and contains no 
 exygen, but consists of: 88-46 carbon. 
 
 11-54 hydrogen. 
 
 100 - 
 
 A glance at the composition of this substance, containing so large an amount of carbon, shows that 
 
LAMPS. 
 
 179 
 
 it must be a powerfully illuminating body, if proper modes "can be adopted of supplying a sufficient 
 quantity of oxygen or air for the entire consumption of the two combustible constituents, and at the 
 same time so regulating the order of combustion that the full amount of light shall be obtained from it. 
 
 Mr. Young was the first who applied the increased draught of air produced by a cone to the flame 
 of oil of turpentine. The burner of Young’s Yesta lamp is shown in Fig. 24-99. It is an ordinary Ar- 
 gand burner with a Liverpool button a, for deflecting the internal current of air, which enters by a 
 space left open near the pinion handle and passes through a, against the inner side of the flame ; b is 
 the wick tube and c the space between the latter and the cone, which only rises in this case to the 
 same level as the burner. Through c a current of air impinges upon the flame at that part where it is 
 expanded by the button d and the internal current of air, and again the air in passing uja the innei 
 sides of the chimney is deflected inwards upon the flame by the contracted portion at e. f is the pinion- 
 handle for raising or lowering the wick. The whole of the burner is screwed upon the glass vessel 
 containing the oil of turpentine, and completely insulated by a ring of wood or other non-conducting 
 material. No metallic tube passes through the spirit to supply ah- to the interior of the flame, as it was 
 supposed that this would become too strongly heated and give rise to acrid and offensive fumes from 
 the volatile spirit. Fig. 2499 shows a plan of Young’s burner. This lamp, when properly managed 
 aud supplied with pure camphene, gives an excellent light, much superior to that produced by any oil 
 lamp ; but if attention is not paid to the management, or the camphene is not pure, it frequently evolves 
 a strong smell of turpentine, producing headache and other disagreeable sensations, or large flakes of 
 soot escape unconsumed and cover every thing in the vicinity. The evolution of smell or soot is always 
 the result of imperfect combustion, and the lamp has been modified in different ways to avoid the pos- 
 sibility of unconsumed products being evolved. 
 
 Seel ion 
 
 The lamp which fulfils the conditions for the perfect combustion of camphene in the most successful 
 manner, is the Gem lamp, a section of which is shown in Fig. 2500. It differs from Young’s lamp, in 
 the mode of deflecting the currents of air, and in allowing the Argand tube supplying the internal 
 current of air to pass through the reservoir containing the oil of turpentine. In Fig. 2500, a is the tube 
 supplying the internal current of air which passes through the reservoir b to the burner d , with which 
 it is in metallic connection, and it is not found that the turpentine is heated by this tube to more than 
 one or two degrees above the temperature which it attains in Young’s lamp ; the temperature of the 
 
180 
 
 LAMPS, SPIRIT-GAS. 
 
 spirit in both cases being from ten to fifteen degrees above the temperature of the surrounding air 
 and this appears to be no more than is required for the proper action of lamps of this description 
 The button/, which deflects the inner current upon the flame, and forces the flame to take an outward 
 direction and come into contact with the first outer current, has the form of an inverted cone, and the 
 deflection of the air is consequently not so abrupt. The supply of air to the inside and outside of the 
 cone is regulated by a series of holes drilled in the brass gallery, and the number and size of these 
 holes are proportioned to the size of the burner, or to the quantity of air admitted through the internal 
 channel. 
 
 Fig. 2501 shows a plan and section of the gallery. C is the space occupied by the inner current of air 
 deflected outwards by the button, A the first series of holes admitting air to the interior of the cone, 
 and B the series of holes through which the air passes to the exterior of the cone. The circle A has 32 
 holes, drilled with a drill one-twelfth of an inch in diameter ; the circle B has also 32 holes, drilled witli 
 a drill one-tenth of an inch, this number and size of the holes having been found by a series of experi- 
 ments most advantageous for a burner of the dimensions represented in the drawing. The cone o, Fig. 
 2501, in this lamp, rises above the level of the wick tube, so that the inner current of air and the first 
 outer current meet the flame below the button at the point represented by the meeting of the two 
 arrows. The outer current of air, passing through the holes in the circle B, meets the flame at a 
 higher level, and insures the complete combustion of any products that may have been uncon- 
 sumed after passing the point where the arrows meet. The height of the chimney will of course 
 materially alter the draught, and an additional quantity of air must be admitted if the chimney is 
 heightened. The proper quantity of air and the direction of the different currents to those parts of the 
 flame where they are most beneficial, are the objects aimed at in the construction of this lamp, and 
 they appear to have been attained more perfectly in the Gem lamp, than in any other spirit lamp yet 
 invented. A Gem lamp of the larger form is reported to give a light equal to 20 wax candles : the 
 light from one of the smaller size is equal to 13 wax candles. 
 
 LAMPS, SPIRIT-GAS. The lamps which we here present are designed to burn the gas of the so- 
 called “ spirit-gas,” which is a composition of alcohol and turpentine distilled together. No wick is 
 burned, and only in the lamp, Fig. 2502, is a wick used, and only for capillary attraction. 
 
 C is the reservoir of the fluid. D is a brass tube extending into the fluid, and it has a cap at the top, 
 perforated all around. F is the flame ignition points of the gas, as it comes out of the perforations. E 
 is the wick ; the wick, by capillary attraction, carries up the fluid by heating the top of the tube D 
 until the fluid becomes gaseous, it then rushes out through the perforations, and is ignited in a state oi 
 inflammable gas, as represented at F. Great numbers of this kind of lamp are now manufactured and 
 used in this city. 
 
 2503 . 
 
 Figs. 2503 and 2504 is another kind of lamp altogether. It does not use any wick at all. Fig. 2503 
 is a front elevation of it, and Fig. 2504 is an enlarged section of one of the burners. A is the camphene 
 reservoir, which can be filled at the top. B is a handle passing down the centre of the vessel and fitted 
 to a conical valve at the bottom, where it joins the top of the central vertical tube, so that the flow from 
 the reservoir may bo cut off at pleasure. Two curved stems carry the burners, the construction of 
 which is particularly represented in Fig. 2504. C on the right is the screwed attaching branch-pipe. 
 The camphene enters by this branch and passes through the diaphragm, as represented by the arrow ; 
 thence upward by a sloping arm into the top horizontal passage D, which is formed on the surface of a 
 circular disk surmounting the whole. It then descends by the opposite arm to the flattened boss E, and 
 rises through a small conical aperture in its centre. This aperture is fitted with a conical spindle, 
 screwed at its lower end, and in one piece with the cup F, which answers as a nut for turning the 
 spindle to adjust the size of the opening. The course of the gaseous matter is then directed through the 
 central chimney G, and is deflected by the inverted cone above it, and it then rushes out by a circular 
 
LATHE. 
 
 181 
 
 ring of eight, ten, or more jets, like those of Fig. 2502. The burner is of brass, and the rest may 
 be all cast in one piece, with the exception of the bottom cup. By unscrewing the cup a wire can be intro- 
 duced to remove any obstructions in the side tubes, but no obstructions are at all likely to get in them. 
 In lighting this lamp a few drops of alcohol is poured into the cup F and ignited, when the heat vola- 
 tilises the campliene in the passages of the burner, which can then be ignited, and the heat resulting 
 from the ignition of the gases so produced, by acting upon the inverted cone at H, keeps up a con- 
 tinuous stream of gas. For suspension lamps, this one has no ordinary qualities to commend it. It no 
 doubt requires attention, but the way in which it heats the fluid, and generates a very rarified gas, 
 renders it capable of giving a very brilliant light. 
 
 LATHE FOR TURNING IRREGULAR FORMS — Blanchard’s. Fig. 2505. This machine is repre- 
 sented in the figure in its most simple form, for turning shoe lasts, and is so constructed that, from one as a 
 pattern, an exact facsimile can be formed from a rough block of wood. Both the pattern and block are 
 fixed on the same axis, and are made to revolve around their common centre, in a swinging lathe, by a 
 pulley and bolt on one end of the axis, as shown in the figure. On a sliding-carriage is attached three 
 posts, through which are fixed pivots, to which are suspended the axles of a cutting and a friction 
 wheel. The cutting-wheel, which is about one foot in diameter, turns on a horizontal axle, and to its 
 periphery is fixed a number of crooked cutters to act like a gouge when the wheel is put in motion. 
 This cutting-wheel is placed opposite the rough block. The friction-wheel, which is of the same diam- 
 eter as the cutting- wheel, is placed opposite the pattern, so as to press against it when in motion. These 
 two wheels are in a line w'th each other, and are attached to the same carriage. On the axle of the 
 cutting-wheel is fixed a pulley, around which passes a band which puts the cutting-wheel in motion by 
 a large drum revolving under it. A crank or first mover communicates motion to the drum, which in 
 its turn transfers a rapid motion to the cutting-wheel, while a band which passes from a small pulley on 
 the drum-shaft, puts in operation a feeding screw-pulley, which moves the sliding-carriage horizontally 
 from left to right. Another pulley on the drum-shaft gives a slow rotary motion both to the pattern 
 and the rough block, in a direction opposite to the cutting-wheel. The friction-wheel is turned by the 
 pattern resting against it. 
 
 During the revolution the pattern, being irregular in its surface, causes the axis to approach and re- 
 cede from the wheel. Thus, it will be seen, as it presents its whole surface to the friction-wheel, so in 
 like manner the block presents its surface to the cutting-wheel, which being in rapid motion, cuts away 
 all that part of the block which is further from the common centre than the surface of the pattern, and 
 thus forms, from a rough block, an exact resemblance of the model. 
 
 Another application of the same principle is shown in Fig. 2506. This machine can turn out a dupli- 
 cate or facsimile of any pattern whatever, and it is now brought to such perfection that an oar-blade, 
 a spoke, a last, and an axe-helve, are all turned upon it with equal facility and equal perfection. 
 
 This is a front view, as seen looking somewhat down upon the machine. A is the frame. B is a 
 large drum. C is a driving-pulley. E> is a band which, from the drum, passes over a pulley E, and 
 drives its rotary cutter- wheel F F. This cutter-wheel is fixed on an axis in a small sliding-frame which 
 moves from one end to the other of the lathe by a cord N winding upon a spindle lying across the ma- 
 chine, which cannot therefore bo seen, but which is driven by the large pulley K, thus giving it a 
 requisite slow motion. H is the pattern axe-helve, and G the rough material to be cut exactly like H. 
 The pattern and rough material are placed in the lathe, represented by the upright frame, and sustained 
 by spindles. On the back part of the machine there is a curious but beautiful sliding-rest, which is the 
 subject of a patent in itself. It moves along after the cutter-wheel, and has two plane faces on which 
 the pattern and cut helve rest. The pattern and helve roll upon the planes, while the rest has a rock- 
 ing motion which accommodates itself to all the uneven turning of the patterns, &c., as they revolve. 
 For turning long articles, this rest is a beautiful and positively necessary part of the machine. To turn 
 a facsimile of any pattern it will at once be evident to every mechanic, that if a pattern be placed A 
 
182 
 
 LATHE. 
 
 a lathe, and the material to be turned be placed with its axis of rotation similar to that of the pattern, 
 and if a guide pressing on the pattern directs a wheel with cutters to operate on the rough material 
 over a surface like the pattern as guided, a perfect representation of the pattern will be produced on 
 what was the rough material — simply by the cutters chipping away all the rough material outside ol 
 the axis of direction — in other words, all the wood on the rough material outside of the pattern. This 
 is the principle upon which this machine is constructed. The cutter-frame slides from one end to the 
 other of the pattern ; and the small guide seen on the framo pressing on the pattern, makes the cutters 
 chip away all the rough material outside of the pattern on G, as tho cutter-frame moves from end to 
 end of the lathe. The cutter-wheel has three motions — a rotary, a horizontal, and an eccentric motion 
 
 2306. 
 
 The pattern and rough material revolve in the lathe. This is done by three pinions on the right, moveu 
 by the pulley seen above K. The speed of the spindles in the lathe is regulated by a very excellent 
 arrangement of a small gang of pulleys and straps, seen on the right at the end of the machine. These 
 pulleys are operated by a lever L, and they are so arranged that a slower motion is communicated to 
 the spindles when the thicker part of the pattern is to be turned, or such a part as an oar-blade. The 
 cutter-frame moves along from one end to the other of the lathe upon a rail, and it is pressed out and 
 in according to the shape of the pattern, by the upper guide ; and the cutter-wheel being directed in the 
 same manner, thus cuts the pattern on the rough material. The strap D is retained in its proper 
 place by a grooved pulley on the cutter-frame, and the whole kept firm and enug to the work to be 
 turned. 
 
 LATHE, SMALL ENGINE. Fig. 2507, side elevation. Fig. 2508, end elevation. 
 
 S is the bed-piece and head-stock, cast in one piece. 
 
 B, spindle which runs in gun-metal boxes. 
 
 C, cone-pulleys on live spindle. 
 
 D, upper cone-pulleys for driving feed-shaft. 
 
 D', lower cone-pulley for driving feed-shaft. It runs loose on a stud, and has a pinion on inner end 
 to drive the two worms. 
 
 E, worms — one right, the other left — which drive the two worm-wheels so as to feed towards the right 
 or left, as the operator may wish. On the worm-geer shaft there is a pinion driving a geer on the shaft 
 above, which has a chain-pinion, around which an endless chain passes, attached to the rest. 
 
 A is a hand-wheel for moving rest by hand. There is a pinion on the other end of the hand-wheel 
 shaft geering into a rack K on the side of the bed, as shown in Fig. 2507. 
 
 F is the tool-holder. 
 
 J, top part of the rest which slides crosswise of the bed by means of the crank and screw. 
 
 l, square spindle, which is moved by hand-wheel Y, and screw inside of shell G. It is held firm ia 
 its place by the handle-nut H. 
 
 a, thumb screw for raising rest. 
 
 m, step-screw. 
 
 b, thumb-screw for adjusting tool in rest. 
 
 This lathe will swing 1 6 inches over the sills and 7 inches over the rest 
 
2507 
 
 V 
 
 LATHE. 
 
 183 
 
•cos 
 
 184 
 
 LATHE. 
 
 
LATHE. 
 
 185 
 
 LATHE, BORING AND REAMING. Figs. 2509 and 2510. I, the main bed-piece, supported by two 
 cast-iron standards. 
 
 I), bead-stock, ■which carries the spindle and cone-pulleys A. 
 
 G, sliding-frame that supports rest P. This frame is traversed backward and forward by means oi 
 the hand-wheel R, which has a pinion on the other end geering into the rack G on side of the bed, (seen 
 in Fig. 2509,) and is held down by the plates N, which hook under the slides S, and is secured bv 
 means of the nuts with handle H, one on each side. 
 
 C510. 
 
 0, face-plate on livo spindle, to which tha work is fastened by bolts when drilling or reaming. 
 
 F, tail-stock, with a traversing spindle, worked by the hand-wheel M, which turns a screw inside o 1 
 spindle in the usual way, for pressing in the drill* or reamers, &c. 
 
 L, hand-wheel on a screw for setting thn tail -stock so as ta make a tapering hole. 
 
 A, cone-pulleys on spindle. 
 
 U, geer on spindle. 
 
 b, pinion on spindle, playing into geer B. 
 
 B, geer on back shaft for reducing motion of spindle and increasing the power — same as is common 
 in geered head-lathes. 
 
 K, handle for throwing the back geer-shaft out of or into geer. 
 
 This machine will bore out a hole 3 inches diameter in a wheel 3 feet diameter 
 LATHE, ENGINE. Figs. 2511, 2512, 2513. Will swing 50 inches in diameter over the ways, and 
 32 inches in diameter over the rest. 
 
 Fig. 2511 is a side elevation of the engine. 
 
 Fig. 2512 is an end elevation. 
 
 Fig. 2513 is a side elevation of the tail-stock. 
 
 P represents the bed-piece which supports the head and tail stocks and rest. 
 
 C is the head-stock in which the live spindle runs ; it is made in a saddle form, and very heavy ; 
 bolted to bed-piece by six bolts. 
 
 B B' are the geers by which the motion of the spindle is reduced and the power increased. 
 
186 
 
 LATHE. 
 
 D D' are small cone-pulleys for driving the long feed-screw, which is on the inside of the bed-piece, 
 and not shown in the drawing. 
 
 O, geer on end of feed-screw, driven by a pinion on the hub of the lower feed-cone D'. 
 
 A, cone-pulleys on spindle of cast-iron. 
 
 F, face-plate with geer B attached to the back side. 
 
 K, tool-holder, which slides upon a swivel-post S, that can be set at any angle and fastened by the 
 lever and screw It to the block N, which slides crosswise of the bed-piece by means of the crank and 
 screw with a balance bolt seen in Fig. 2511, and at N' in Fig. 2512. 
 
 G is a hand-wheel for traversing the rest by handcraft. This wheel runs on a stud, with a pinion on 
 its hub which works into the geer H. H is placed on the end of a short shaft with a pinion h on the 
 other end, geering into the rack I attached to the side of the bed. 
 
 T is the main sliding-saddle or plate for the rest ; it is very heavy, and permanently fitted to the 
 slides and hooked down by pieces J, and is well adapted to fastening on heavy work for boring, &c. 
 
 M, lever for changing the direction of the feed. 
 
 U, handle for stopping and starting feed. 
 
 L is the lower part of tail-stock, w'hich is notched on to the slides or ways of the bed-piece. 
 
 Q, upper part of the tail-stock, which is made to slide crosswise for tapering work, in the usual way 
 
LATHE. 
 
 1S7 
 
 2512. 
 
' 2511 . 
 
 LATHE. 
 
 
 LATHE. 
 
LATHE. 
 
 180 
 
 LATHE, LARGE BORING AND REAMING. A very convenient and useful tool for boring and 
 reaming locomotive and car -wheels, pulleys, geers, &c., &c. It -will turn out a hole straight or tapering, 
 and spline the same, -without removing it from the chuck. It is adapted to turning or drilling out 
 holes, or boring, by using the shell boring-tool ; all self-feeding. 
 
 Fig. 2514 is a side elevation. 
 
 Fig. 2515, end elevation, looking towards the face-plate. 
 
 A, cone-pulley of cast-iron which runs on the live spindle. The spindle has strong journals, running 
 in gun-metal boxes. 
 
 A', geer on face-plate. 
 
 B, geer on front shaft. 
 
 o, shaft, thrown out of and into geer by eccentrics. 
 
 C, face-plate, to which the work is fastened by means of bolts. 
 
 D, upper cone for driving the feed motion. 
 
 D', lower cone on the splined shaft which passes through the centre of bed-piece, giving motion to 
 the rack I, which can be connected with the spindle J, by the screw on top. 
 
 2515. 
 
 F, head-stock in which the live spindle rests. 
 
 G, swivel-post on which the tool-holder slides, 
 
 g, bed-piece on which G stands. 
 
 G', rest, with jaws, for using flat drills and reamers, adjusted by the screw on top. 
 
 H, upper part of tail-stock, inside of which is the feeding apparatus. This piece rests upon a sliding- 
 plate that is traversed crosswise by the screw L. 
 
 S, worm which geers into a segment on side of tail-stock for giving the proper angle when a hole is 
 to be turned out tapering. 
 
 K, crank, with a bevel pinion on the inside end of its shaft, geering into a large bevel-wheel that has 
 an internal screw cut through its hub for fastening down tail-stock to the bed. 
 
 M, stand cast on the side of the lower piece of tail-stock, carrying a shaft and pinion geering into a 
 rack on side of bed-piece, for the purpose of moving tail-stock by hand. 
 
 M', pinion, geering into rack. 
 
 N, rack on side of bed-piece. 
 
 O, bed-piece, cast with cross-pieces and made very strong. 
 
 This lathe will admit a wheel 5J feet in diameter, and is adapted to turning off the rims of pulleys, 
 »nd for surface turning generally. These engines (pp. 166 to 172) are from the Lowell Machine Shop 
 
190 
 
 LATHE. 
 
 LATHE, FOR GUN BORING, TURNING, AND PLANING, arranged for the Ordnance Depart 
 ment, U. S. Navy Yard, Washington, by ffi. M. Ellis, Engineer. Figs. 2516 to 2522. 
 
 Fig. 2519. c, rest for supporting the muzzle of the gun ■while boring. 
 
 d, pulley, -with belt motion above, for drawing boring-bar. 
 
 When boring, the turning mandrel is taken out and the boring-bar put in its place; the back head ,« 
 forced up by feed-screws in the same manner as slide-rest for turning. 
 
 Fig. 2518. C, planing-head and tool-holder, bolted on slide-rest of lathe in place of tool-holder foe 
 turning. 
 
 h, slide of tool-holder. 
 
 i', cogged sector working in rack on bottom of drill of tool-holder. 
 
 i, shifting crank to convey motion to sector. 
 
 E, ratchet-wheel on main mandril of lathe, to give motion to gun on the centres while planing be- 
 tween the trunnions. 
 
 D, eccentric connection to give motion to feed-hand. 
 
 B, bevel-geer to work planing-head and feed-hand. 
 
 A, pulleys on bevel pinion-shaft. 
 
 Fig. 2516. Back (sliding) head for turning or boring. 
 
 k, lever for throwing head out of geer. 
 
 l, feed-screw. 
 n, gibs. 
 
 Fig. 2520. h, lever for throwing slide-rest out of geer. 
 f, feed-screw. 
 
 m, half-rest for feed-screw. 
 n n, gibs on slide-rest. 
 
 Fig. 2521. d, pulley for drawing boring-bar. 
 e, ratchet-wheel. 
 
 f lever on ratchet-wheel, for boring. 
 
 Fig. 2517. c, planing-head for planing between trunnions. 
 h , tool-holder. 
 
 Fig. 2522. Standing-head. 
 b, feed-geer, (same in Fig. 2519.) 
 t7, handle for changing feed-geer. 
 
2518 
 
 LA'flIE. 
 
 191 
 
■CISC 
 
 LATHE. 
 
 192 
 
LATHE. 
 
 193 
 
 LATHE, SMALL SELF-ACTING AND SCREW-CUTTING, by Charles Walton, Leeds, Eng 
 Fig 2523 is a general side elevation of the lathe, and 
 Fig. 2524 is a plan corresponding. 
 
 Fig. 2525 is an end elevation showing the geering. 
 
 Fig. 2526 is a transverse section taken between the fast-head and the slide-rest, showing the lattei 
 in elevation, as also the arrangement of the geering for traversing the same. 
 
 Figs. 2527, 2528, 2529, 2530, show details of the geering for working the slide-rest. 
 
 Fig. 2231 is an elevation of the top cone and driving pulleys : these consist of two sets, the smaller 
 *et being used for reversing the motion of the saddle when the lathe is employed in screw-cutting, and 
 the larger^when the tool is in action, and a slower motion consequently necessary. 
 
194 
 
 LATHE. 
 
 Fig. 2532 is a section through the driving-cone on the lathe-spindle. 
 
 Fig. 2533 is a front view of the chuck. 
 
 Fig. 2534 is a side elevation of the same ; and 
 
 Fig. 2535 a vertical section in the plane of the lathe-spindle. 
 
 These figures exhibit in full detail the several parts of a very efficient, and, in many respects, conve 
 ment self-acting and screw-cutting lathe. 
 
 The machine is carried upon three standards marked A, and of which the general forms are shown 
 in Figs. 2525 and 2526. These standards are planed on their upper surfaces to afford a solid rest for 
 the bed BB, the upper surface of which is also planed. The exterior edges of the bed are bevelled in 
 the usual way, as a means of retaining the saddle-plate L L of the slide-rest, as shown in the cross- 
 section, Fig. 2526. The fast-head C C is fastened to the bed by means of bolts : it carries the main 
 spindle D, upon which is the driving-cone a, a section of which, showing its relation to the spur-wheel e 
 and pinion b, is the subject of Fig. 2532. The cone is as usual loose upon the spindle, and cau be 
 attached at pleasure to the wheel e, which is fast upon the spindle, when it is necessary to throw the 
 back-speed shaft E out of geer. This is effected by the hand-rail G, which connects the two levers 
 commanding the bearings of the shaft in the two standards of the fast-head, a method commonly 
 adopted when the arrangement of the geering does not conveniently admit of the shaft being shifted 
 longitudinally. The motion of the leading-screw FT is derived from the cone-spindle through the train 
 of wheels v w x y z, in screw-cutting ; and in plain work the parallel motion of the tool is obtained 
 through the train v a' e' c, and the band-pulleys b' and c', to the traverse-spindle f'f, which, by means 
 of the worm <j, Figs. 2526 and 2530, and worm-wheel i' communicates through the intervening spur- 
 pinions r and s with the pinion t, Fig. 2527, geering with the toothed-rack u, Figs. 2526 and 2529 
 attached to the under side of the saddle-plate L of the slide-rest. The geering for reversing the motion 
 of the saddle consists of three meter- wheels and the clutch-box k', arranged upon the traverse-rod f f' 
 The clutch k' communicates by means of a spanner fixed upon a horizontal shaft, passing through the 
 
 2531. 
 
 bed of the lathe, with the reversing-lever V in front. By this means the shaft communicating with the 
 train of wheels from the cone-spindle maybe geered either directly with the traverse-rod /'/', or 
 through the intervention of the meter-wheels at pleasure. A weighted lever j', shown in Fig. 2526, 
 serves the purpose of throwing the worm-wheel i' in or out of geer with the worm upon the traverse- 
 rod, thereby connecting or disconnecting the lathe with the saddle of the slide-rest ns may be required. 
 The slide-rest can be relieved from connection with the leading-screw N by means of the handle o at- 
 tached in front of the saddle : by pressing this handle down, it acts upon a stud in the plate, carrying 
 the screw-box n, which is thereby opened, and the saddle relieved. 
 
 The movable head-stock J J is provided with a screw/ for shifting it out of the line of the axis of 
 the main spindle, thereby adapting the lathe to conical turning. 
 
 Action of the lathe. — The arrangement of the geering in the views given of the lathe in the plates, is 
 that adapted to screw-cutting. The cone a, which is loose on the spindle, is fast to the pinion b of 13 
 teeth; this pinion geers with the wheel c of 52 teeth upon the back-speed spindle E, which also carries 
 the pinion d of 13 teeth, geering with the wheel e of 52 teeth, fast upon the cone-spindle D. According 
 to this arrangement, the ratio of the speed of the driving-cone to that of the main spindle is as 16 to 1. 
 
 The connection between the cone-spindle and the leading-screw FT is accomplished by means of the 
 wheel v of 40 teeth, fast upon the driving-cone spindle ; this wheel is working into the wheel w of 60 
 teeth, upon a shifting-stud attached by means of a radial slot-bar to the bracket 0, bolted upon the 
 fast-head: this latter wheel again is in geer with the wheel x of 90 teeth, also upon a shifting-stud, and 
 carrying a wheel y of 45 teeth, in geer with the wheel z of 90 teeth, fast upon the leading-screw shaft 
 N. This train can, of course, be varied at pleasure to suit the particular pitch of screw to be cut, the 
 positions of the radial slot-bars, carrying the studs of the carrier-wheels, being at the same time shifted 
 to allow the wheels to come into geer. 
 
 To adapt the lathe for plain sliding, the back-speed shaft is put out of geer with the cone-spindle, by 
 means of its hand-rail G: the wheel v upon the cone-spindle then s;e.ers with the wheel a', working 
 
LATHE. 
 
 I fin 
 
 loose upon a stud attached to the head-stock, and carrying the cone-pulley b’. This last is connected by 
 a band with the loose cone-pulley o', working likewise upon a stud fixed to the standard A, and carry- 
 ing a wheel d', which geers into the wheel e', fast upon the end of the traverse rod /'/', on which are 
 the three meter-wheels and clutch-box k', also the sliding-worm which works into the cone-wheel i 1 upon 
 the shaft q. This shaft revolves in bearings attached to the saddle, and carries the pinion r, Fig. 2527, 
 working into the wheel s, keyed upon the same spindle which carries the pinion t, also fast. This latter 
 geers with the rack u bolted to the under surface of the saddle. By this arrangement motion is trans- 
 ferred from the cone to the traverse-rod /'/', and thence to the slide-rest through the geering attached 
 to the saddle. 
 
 Literal references. — A A A the standards upon which the lathe is supported. 
 
 B B the bed or shears having the upper ledges upon which the shifting head-stock and saddle rest, 
 planed. 
 
 C C the fast-head, which is firmly bolted upon the bed. 
 
 D the main spindle, which is highly finished and case-hardened. It revolves in conical collars of 
 hardened steel, and is further secured against end-long shift by a set-screw bearing against its outer end 
 through the bracket I. 
 
 E tlie back-speed shaft revolving in bearings inserted in the projecting lv.gu F F, cast on the standards 
 of the fast-head. 
 
 G hand-rail for throwing the back-speed shaft in and out of geer with the cone-spindle. 
 
 H the face-plate which is screwed upon the end of the main spindle. 
 
 I bracket bolted to the outer standard of the fast-head ; see D. 
 
 J J the movable head-stock. It is planed and fitted upon a saddle K, both the upper and tinder 
 surfaces of which are planed ; on the upper to allow the head-stock to slide upon it transversely, and 
 on the under to allow of its being travelled on the bed of the lathe. 
 
 L L the saddle-plate of the slide-rest. It is planed and fitted with bevelled pieces to retain it upon 
 the bed of the lathe, as shown in Fig. 2526. 
 
 M the tool-holder of the slide-rest. 
 
 N the leading-screw, carried in bearings at its two extremities, attached in front of the lathe. 
 
 0 the bracket for carrying the train of carrier-wheels by which the motion of the main spindle is 
 transmitted from the leading-screw. 
 
 P, Figs. 2533, 2534, and 2535, the front plate of the universal chuck. And 
 
 Q the back plate of the same, showing the spiral groove for expanding and contracting the clutches 
 or jaws. 
 
 R R R the clutches or jaws of the chuck. These are fixed upon separate soles through which one of 
 the tails passes, while the other passes over the inner end of the sole ; these tails slide between radial 
 slots in the front plate P, and enter the spiral grooves formed in the face of the back plate Q. When 
 the back plate is turned upon its axis, which coincides with the axis of the main spindle, the front plate 
 being meantime held fast, the clutches or jaws will be guided simultaneously, further from, or nearer to 
 the centre, and thereby be made to clutch the work in the usual way.* 
 
 a the driving-cone of the lathe ; it is loose upon the main spindle, and fast to 
 b the first pinion of 13 teeth ; it is fast to the driving-cone a. 
 c wheel of 52 teeth on the back-speed shaft E ; and 
 d a pinion of 13 teeth on the same shaft. 
 e first wheel of 52 teeth on the main spindle of the lathe. 
 f screw for moving loose head-stock transversely for conical turning. 
 g hand-wheel for working the spindle of the loose head-stock ; and 
 h a handle for tightening the pinching-screw of the same. 
 
 1 adjustable check by which the slide-rest M is retained upon the saddle-plate L. 
 j rest-plate for the tool-carrier ; and 
 
 k a screw for fixing the tool-holder upon the slide-rest. 
 
 I a hand-wheel and handle upon the end of the transverse-screw of the side-rest. This screw works 
 in plain collars attached to the saddle-plate, and in a nut attached to the sliding-sole of the rest, so that 
 the screw being turned it carries the slide from or towards the axis of the lathe. 
 m a crank-handle upon the upper slide-screw, for putting the tool in and out of cut. 
 n the screw-box for the leading-screw. The under part is screwed internally to the same pitch as 
 the leading-screw, and is carried upon a sliding-sole, into which is inserted a stud passing through 
 a slot in 
 
 o the handle for connecting and disconnecting the screw-box of the leading-screw. It acts as a lever 
 of the second kind, the stud of the sliding-sole of the nut passing through a slot in it, between the ful- 
 crum and the part acted on by the hand. 
 p the crank-handle for working the saddle-plate by hand ; it is placed upon 
 
 q the transverse-shaft upon which is the screw-wheel i‘, working into the sliding-worm g', carried 
 along the rod/'/' by a fork Id attached to the saddle-plate. 
 r a spur-pinion keyed upon the transverse-shaft q, and working into 
 
 s a small spur-wheel keyed upon a short spindle, attached by bearings on the bottom of the saddle 
 plate, and which geers with the pinion r on the transverse-shaft q. 
 t a spur-pinion keyed on the same spindle as s, and which geers with 
 u an inverted rack fast to the bed of the lathe. 
 
 * This arrangement has an advantage over the mode of working the clutches by separate screws, in their being simul- 
 taneously expanded and contracted in respect of the centre ; but it frequently happens that it is necessary to chuck articles 
 which are not cylindrical, and in which it is more convenient to have the clutches movable, independently of one another. 
 As a familiar example may be instanced hall-lap coupling ends of shafts, which are semi-cylindrical, and must be made up 
 by packing to the cylindrical form before they could be caught in a chuck of this kind. 
 
196 
 
 LATHE. 
 
 v the first pinion in the trains of the head-geering of the lathe. 
 
 w a carrier-wheel which geers with the pinion v ; it is loose upon a stud in the stud-plate 0. 
 x a second carrier-wheel upon another stud in the stud -plate O, geering with the former. 
 y a third carrier-wheel on the same stud as the wheel x, and made fast to the latter, 
 z a wheel keyed upon the end of the leading-screw, and geering with the pinion y. 
 
 It is through this train that the leading-screw derives its motion from the main spindle of the lathe. 
 a' a wheel of the back-train geering with the pinion v, on the end of the main spindle ; it is keyed 
 upon a pap of 
 
 b the upper cone of the back-train, carried upon a stud in the standards of the fast-head. It is loose 
 upon the stud, and has the eye prolonged into a pap upon which the wheel a' is keyed. 
 
 c' the lower of the two cones of the back-train. It is also loose upon its stud, and is connected by 
 a band with the upper speed-cone b‘. 
 
 d’ a spur-pinion keyed upon the eye of the speed-cone c', which is prolonged for that purpose, and 
 which geers with 
 
 e' a spur-wheel on the end of the worm-shaft f'f, geering with the pinion d' . 
 
 f'f the traverse-rod or worm-shaft ; a grooved rod passing at the back of the lathe, and having its 
 bearings at the two extremities. It is also supported between by the fork which slides the worm g' 
 alone; upon it, the projecting sides of which are formed into a species of double gallows, as shown in 
 Figs. 2526 and 2530. 
 
 g' worm or endless screw upon the traverse-spindle, geering with the worm-wheel V. It has a fixed 
 key in the eye which slides in a groove in the rod f'f. 
 
 i' worm-wheel on the end of the transverse-shaft q, worked by the worm g'. 
 j' a weighted lever for disconnecting the worm-wheel i'. 
 
 k' reversing-geer upon the worm-shaft f'f, consisting of the three meter-wheels and clutch-box, ar- 
 ranged in the usual manner, and worked by 
 
 V the lever of the reversing-geer k'\ it acts by a spanner upon the clutch-box lever, bringing the 
 clutch into geer with either of the wheels upon the worm-shaft at pleasure. 
 
 LATHE, BACK-GEER TURNING. This is a good specimen of a back-speed lathe. 
 
 Fig. 2536 is a side elevation of the fast-head ; Fig. 2537 an end elevation of the same taken from the 
 back, and Fig. 2538 is a plan of the fast-head. The same letters are used on each. 
 
 2537. 
 
 b, the driving cone-pulleys, loose on the spindle of the lathe and fast with the pinion p, Fig. 2538. 
 h, a spur-wheel, fast on the back shaft, and i a pinion also fastened on the same, w, a wheel fast on 
 the lathe-spindle, geering with the pinion i. c, is the chuck or face-plate ; this admits of being taken 
 off the lathe-spindle when not required. The spindle is kept forward by a back-centre pinching-screw. 
 
 Figs. 2541 and 2540, are end and side elevations of the shifting-head of which Fig. 2539 is a plan, 
 is a screw for shifting the spindle. A hand-wheel is placed on the outer end of it, which revolves in 
 
LATHE. 
 
 19? 
 
 a gland embracing the ends of the shifting- 
 spindle and a guide-rod under the screw, 
 
 Fig. 2540 ; by this means it is made to 
 move horizontally, and to carry the shift- 
 ing-spindle of the head along with it. u is 
 an eye-bolt, tightened up by the traveller r 
 on the spindle, to take the strain off the 
 screw. When quicker speeds are wanted, 
 the shaft carrying the wheels h and i is 
 moved back by taking out a pin seen under 
 h in Fig. 2537, and the cone is made fast to 
 the wheel w by a latch in the usual way. 
 
 LATHE, BORING AND TURNING, 
 by Mr. Kinmonds. 
 
 " Fig. 2542 is a side elevation of the ma- 
 chine. 
 
 Fig. 2543 is a general plan corresponding. 
 
 Fig. 2644 is an end view from the left. 
 
 Fig. 2545 is a section taken in front of 
 the shifting head-stock. 
 
 The fixed head-stock B B is provided 
 with four bearings, cast in each of the two 
 standards, for the purpose of receiving the 
 cone-spindle C, the second motion shafts 
 D and E, and the main spindle F, upon 
 which the face-plate G is fixed. The geering of the machine 
 is calculated to produce a series of variations in the speed of 
 the main spindle F, independently of any variation which may 
 be effected by means of the driving cone-pulley a. 
 
 To effect this the arrangement of the wheels upon the 
 shafts D and E is such that either of them may be thrown 
 into geer with the cone-spindle C, and the internal wheel g, 
 on the back of the face-plate G. Thus, if the wheel e on the 
 shaft D be brought into geer with the wheel d, on the cone- 
 spindle, the pinion / will at the same time be in geer with the 
 internal wheel g, and a quick motion will be communicated 
 to the face-plate ; but if the opposite shaft E be slid forward 
 longitudinally till the wheel j geers with the pinion h, the 
 pinion /' on that shaft will be thrown into geer with the in- 
 ternal wheel, and a slower motion will consequently be im- 
 parted to the face-plate. Again, let both the shafts D and E 
 be thrown out of action ; the cone-spindle 0 may then be 
 directly connected with the main spindle F by means of the 
 wheels b and c, the relative sizes of which may be varied so 
 as to produce any required velocity ; this latter arrangement 
 is only employed for obtaining a high speed, as in the case of 
 polishing. 
 
 The loose head-stock H is adjustable to any required posi- 
 tion by means of a crank-handle fitting upon the square end 
 of the spindle marked o, which communicates by a train of 
 toothed geer with the rack M, fixed upon the bed-plate of the 
 machine, as shown in Fig. 2546. The pinion which works 
 into the rack is keyed upon the spindle p, carried in bearings 
 attached to the sole of the head-stock. On the same spindle 
 is a small bevel-wheel, which geers with a pinion on the 
 lower end of a vertical spindle, having its bearings in the 
 interior of a hollow column, cast in the body of the head- 
 stock. On the upper end of this spindle is another bevel- 
 wheel, which geers with a pinion on the horizontal spindle o 
 
198 
 
 LATHE. 
 
 thereby completing the connection with the fixed rack M. This arrangement is fully exhibited in dotted 
 lines in Fig. 25 1C. 
 
 The same rack M serves also for moving the side-rest K in a longitudinal direction, by means of a 
 pinion keyed upon the shaft q, shown in Fig. 2543. This shaft is carried in bearings attached to tl a 
 edge of the sole-plate of the slide J, 
 and terminates in a square , to which a 
 lever may be applied to give motion 
 to the shaft. The sole-plate of the 
 slide is provided with dovetail grooves 
 in its under surface, to receive the cor- 
 respondingly formed heads of two bolts, 
 for the purpose of attaching and fixing 
 to the saddle-plate J the sole of the 
 bracket K, which carries the slide-rest 
 L. To afford the utmost possible facility 
 for adjustment, the bolt holes in the 
 sole of the bracket K are slots of con- 
 siderable length, and the fixing bolts 
 hold the two plates firmly together, 
 metal to metal, their surfaces of contact 
 being planed true. 
 
 By this arrangement the slide may 
 be made fast in any position upon the 
 saddle plate, which in turn is retained 
 upon the bed-plate of the machine by 
 wedge-pieces worked by means of two 
 horizontal eccentric spindles v v, shown 
 in Fig. 2543. 
 
 The longitudinal and transverse mo- 
 tions of the tool-holder, for the purposes 
 of traversing the work, and placing the 
 tool in and out of cut, are obtained by 
 means of the screws r and s, which work 
 a' right angles to each other, in the 
 usual manner ; the tool is made fast on 
 the tool-holder by means of the two 
 e.amps 1. t. In adjusting the slide pri- 
 marily to the work the sole K is re- 
 leased from the saddle-plate J by re- 
 laxing the connecting bolts ; the bracket 
 K is then shifted to the required dis- 
 tance from the longitudinal axis of the 
 machine, and also, to a certain extent, 
 in the line of that axis by sliding the 
 bolts in the dovetail grooves of the 
 saddle-plate, should that operation be 
 more convenient than moving the latter 
 on the bed-frame of the machine. For 
 ' transverse adjustment to a limited ex- 
 tent, the screw s can be used ; for lon- 
 gitudinal adjustment, the tool-carrier 
 may be set in a similar manner by the 
 screw r. 
 
 Action of the machine. — Supposing 
 it is required to face a heavy piece of 
 work by this machine, it is clamped to 
 the face-plate by means of bolts which 
 pass through radial slots formed in the 
 latter. The wheel c, upon the end of 
 the main spindle F, is then removed, 
 and the shaft E is slid longitudinally in 
 its bearings until the wheel j and the 
 pinion f, both keyed upon it, geer 
 respectively with the pinion h , upon 
 the cone-spindle, and the internal wheel 
 g, which is fast upon the back of the 
 face-plate. By this arrangement the 
 slowest motion of the face-plate is ob- 
 tained. If a quicker motion be required, as when the action of the tool is near the axis of the machine, 
 the shaft E is thro wn out of geer, (as shown in the views, Figs. 2542 and 2543,) and the shaft D is moved 
 endways until the wheel e and piuion f upon it geer respectively with the wheel d upon the cone- 
 spindle, and the internal wheel g upon the back of the face-plate. The speed is thus increased in the 
 ratio of the number of teeth in the wheel d and pinion li ; that is, as 51 to 15. A still higher speed, 
 
LATHE. 
 
 199 
 
 and indeed the highest, is obtained by arranging the geering of the machine as it is represented in the 
 engravings. The shafts D and E, it will be observed, are both out of geer, (being retained in that 
 position by the catches k lc',) and the wheel b upon the cone-spindle C is in geer with the wheel c, upon 
 the end of the main spindle F, so that the speed of the cone is transmitted to the face-plate through the 
 single pair of wheels b and c, which are to each other in the ratio of 51 to (50. 
 
 These three speeds, which are independent of the five speeds obtained by the cone, may be thus 
 compared : — The numbers of teeth in the wheel j and pinion f upon the back-shaft E, are respectively 
 78 and 13, and the numbers in the pinion h, upon the cone-spindle, and in the internal wheel g upon the 
 back of the face-plates, are 15 and 1 19 ; consequently when the shaft E is in geer, the ratio of the speed 
 between the cone-spindle and the face-plate is as 78 X 119 : 13 X 15, or as 47'6 to 1, being the- slowest 
 motion of which the machine is capable. Again, the numbers of teeth in the wheel e and the pinion / 
 upon the shaft D, are respectively 51 and 13 ; and the numbers in the wheels d upon the cone-spindle, 
 and the internal wheel g, being 51 and 119, therefore when the shaft D is in geer, the ratio of the speed 
 of the cone-spindle to that of the face-plate is as 119 : 13, or as 9T5 to 1. And when both of these 
 shafts are out of geer, and the wheel b upon the cone-spindle is working into the wheel c upon the mai>" 
 spindle, the numbers of teeth being respectively 51 and 66, the ratio of the speed is 1 to T3 nearly. 
 
 2545 . 
 
 The action of the machine in ordinary parallel turning is the same as in any common lathe. The 
 mode of obtaining a self-acting longitudinal motion of the tool-carrier is by a stellar-plate fixed upon 
 the end of the screw r, and which is worked by an arm bolted to the face-plate or to the object which is 
 being turned, so as to come in contact with the plate, and cause it to advance one tooth at each 
 revolution. 
 
 Application of this lathe to the boring of cylinders . — When the machine is to be used as a boring- 
 mill, the slide-rest and shifting head-stock are removed, and a boring- bar is substituted ; one end being 
 supported by a standard fixed upon the bed-plate. 
 
 Literal References. 
 
 A A, the bed-plate of the machine. 
 
 B B, the fixed head-stock, bolted to the bed-plate. 
 
 C, the driving cone-spindle. 
 
 D E, the second motion shafts. 
 
 F, the main spindle carrying the face-plate G. 
 
 a, the driving cone-pulley with five speeds. 
 
 b, a wheel of 51 teeth working into 
 
 c, a wheel of 66 teeth on the main spindle. 
 
 d, a wheel of 51 teeth working into 
 
 e, an equal sized wheel on the second motion 
 shaft D. 
 
 //'.pinions of 13 teeth on the shafts D and E, 
 working into 
 
 g, the internal wheel of 119 teeth attached to the 
 face-plate. 
 
 h, a pinion of 15 teeth working into 
 
 j, a wheel of 78 teeth upon the second motion 
 shaft E. 
 
 k k', catches for retaining the shafts D and E when 
 put in or out of geer. 
 
 1 1, stay-rods for strengthening the fixed head- 
 stock. 
 
 H, the shifting head-stock. 
 
 jw, a screw-spindle with hand-wheel for adjusting 
 the centre in the shifting head-stock. 
 
 n, a pinching-screw for fixing the centre when ad- 
 justed. 
 
 o, a spindle for moving the shifting head-stock 
 longitudinally. 
 
 p, a transverse shaft forming part of the mechan- 
 ism by which the shifting head-stock is moved. 
 
 h' h', hooked bolts for filing the shifting head 
 stock. 
 
 J, the saddle-plate, forming a support for 
 
 Iv, a bracket for carrying the slide-rest. 
 
 L, the longitudinal carriage of the slide-rest. 
 
200 
 
 LATHE. 
 
 M, the toothed rack, fixed to the bed-plate for the 
 purpose of moving the slide-rest and shifting 
 head-stock. 
 
 q , a shaft carrying a pinion which works into the 
 rack M, for moving the slide-rest longitudi- 
 nally. 
 
 r, longitudinal screw of the slide-rest. 
 
 s, transverse screw of do. 
 
 1 1, clamps for fixing the tool upon the slide-rest 
 u, screw for fixing the slide-rest. 
 v v, screws for fixing the saddle-plate. 
 
 LATHE, BORING MILL AND LARGE TURNING LATHE. This is an indispensable tool in 
 works where engines of a large class are constructed. The plates exhibit a side elevation and plan, 
 with the parts marked by the same letters of reference. 
 
 A, the boring-bar, having a recess in it to receive the feeding-screw ; see Fig. 2547. 
 
 C C and D D, brackets for carrying bar. 
 
 B, bed-plate for fixing the work by T-headed bolts, passing through the longitudinal slots cast in it. 
 
 E, Fig. 2547, boring-block, fitting accurately on the bar ; it is moved along it by the feed-screw 
 
 working into the nut v, inserted into the boring-block. 
 
 H, main spindle carrying the driving cone-pulleys. 
 
 G, the face-plate for fixing the work to be turned. 
 
 S, Fig. 2548, a cylinder undergoing the process of boring. 
 
 t, bars for fixing the cylinder to the bed-plate. 
 
 y, a coupling bolted to the face-plate for the purpose of driving the boring-bar. 
 
 a, pinion fast to driving cone-pulleys and to the boss on the spindle H. 
 
 b, wheel fast on the shaft o, and geering with the pinion a. 
 
 c, pinion driving the wheel d, but which may be slid along the shaft on a sunk feather towards g, so 
 as to be clear of d when required. 
 
 g, wheel fast on the shaft o. 
 
 h, wheel which geers with the wheel g, when required. 
 
 c, wheel on the shaft p, which geers with that marked b, on the shaft o. 
 
 k, internal wheel fast on the back of the face-plate G. 
 
 i, pinion fast on the shaft p, and geering with the internal wheel Jc, to communicate motion to the 
 face-plate. 
 
 ss, planed rails for the brackets C and D, or other supports that may be used to carry lathe-heads. 
 
 w, x, boring-rings ; the internal ring w is usually bored to fit E, and allowed to remain on the boring- 
 block, the larger ones being keyed on it. The ring x, suited to bore the cylinder s s, has 24 slots in its 
 circumference ; 12 of these receive the cutters, which are adjusted and fixed by small wedges ; some- 
 times they are bedded on paper. The other slots are fitted with pieces of hard wood driven tightly 
 into them to form a general guiding surface. 
 
 I, wheel loose on the boring-bar, and having external and internal teeth. The internal teeth geer 
 with those of a pinion on the end of the feed-screw ; see Fig. 2549. 
 
 m, wheel fast on the boring-bar, and having the same number of teeth as the wheel l, (64.) 
 
 n, q , wheels fast on the small shaft u, and geering with m and l. The wheel q has one tooth less 
 than n, (35 and 36,) so that one turn of the wheels n and q advances the wheel l one tooth on the bar, 
 and (the internal wheel having the same number of teeth as the external) produces a motion of one 
 tooth of the screw-pinion. The screw being -J- inch pitch, and the piston 16 teeth, the feed motion of 
 
 5* ** *03125 X 64 
 
 the boring-block will be — = '03125 inch for each turn of the wheels n and q, or = .0571 
 
 b 16 1 35 
 
 inch during one turn of the boring-bar. 
 
 The following table exhibits the various speeds of which the boring-bar is susceptible. 
 
 
 Turns per minute. 
 
 Turns per minute. 
 
 1 
 
 •333 
 
 X 3 = 1 
 
 13 
 
 4-839 
 
 o 
 
 •416 
 
 
 14 
 
 6-049 
 
 3 
 
 •520 
 
 
 15 
 
 7-561 
 
 4 
 
 •650 
 
 y/ -650 x 3 = 1-4 
 
 16 
 
 9-451 
 
 5 
 
 •812 
 
 y/ -812 X 3 = 1-56 
 
 17 
 
 11-814 
 
 6 
 
 1015 
 
 18 
 
 14-767 
 
 7 
 
 1-269 
 
 
 19 
 
 18-457 
 
 8 
 
 1-586 
 
 
 20 
 
 23-079 
 
 9 
 
 1-982 
 
 1-982 X 3 = 5-946 
 
 21 
 
 28-842 
 
 in 
 
 2-478 
 
 
 22 
 
 36-053 
 
 1 1 
 
 3-077 
 
 
 23 
 
 45-066 
 
 12 
 
 3-871 
 
 
 24 
 
 56-333 
 
 The speeds increase as 1 to 1$, so that any speed within the range may be procured to within § of 
 
 84 
 
 that required ; that is, the boring speed being 7 feet per minute, the greatest deviation will be — = 10 J 
 inches per minute. 
 
 The cone-pulleys of the machine are driven by a similar set of cone-pulleys on an intermediate shaft. 
 This shaft is again driven from the main shaft by pulleys of the following relative diameters : 
 
 3 feet. 
 
 I § in. 
 
 | 22i in. | 
 
 3 feet. | 
 
 The diameters of these pulleys are to each other as the first to the fifth speed of the bar, so that the 
 smaller is to the larger pulley as ■J ZZZ : i/812 = 1 : T56. The increase of speed from the largest 
 
LATHE. 
 
 201 
 
LATHE. 
 
 202 
 
 f 
 
 I 
 
 i 
 
 
LATHE. 
 
 203 
 
 to the smallest pulley on the spindle H is as the first to the fourth speed, and the diameters of the 
 pulleys are v/’333 : ^/'650 = 19 : 2GJ. 
 
 The first eight speeds are obtained with the wheels d and c, the second eight with the wheels b and 
 f, and the third eight by geering g and h, disengaging e and c, and taking the pinion i out of geer with 
 the large internal wheel on the face-plate by shifting the shaft p towards the shaft o. 
 
 Driving Wheels, 
 
 a, .. 
 
 b, .. 
 
 c, . 
 e , .. 
 
 d, .. 
 9,-- 
 A,. 
 i, .. 
 A,., 
 
 Numbers of Teeth in Wheels. 
 
 Feed Wheels. No. of Teeth. 
 
 /, external, 64 
 
 l, internal, 64 
 
 m 64 
 
 n, 36 
 
 q , 35 
 
 Pinion on traverse ) , „ 
 
 r it 
 
 No. of Teeth. 
 
 24 
 
 52 
 
 40 
 
 14 
 
 64 
 
 34 
 
 40 
 
 15 
 
 144 
 
 The speeds produced by the wheels e d and b c are to 
 each other as the first to the ninth speed of the chuck ; 
 therefore, 64 X 52 -r- 14 X 40 = 5'94 nearly. 
 
 The boring speed being about 7 feet per minute, the 
 slowest speed, viz., § of a revolution per minute, would 
 
 84 X 3 
 
 cut a cylinder of 80 inches diameter = 80. All 
 
 J ■ 3T416 
 
 the cylinder boring speeds are in the first eight of the 
 table, the others are for turning and polishing heavy 
 articles, such as large cylinder covers. 
 
 Another modification of the boring-lathe is seen in the 
 vertical boring-mill of J. P. Morris & Co., of Philadelphia. 
 
 A modification of the reaming and boring-lathe may 
 be seen in the vertical boring-mill built in the Washing- 
 ton Navy Yard, under the direction of Wm. M. Ellis. This 
 is essentially the same as the boring-mill of J. P. Morris 
 tk Co., of Philadelphia. 
 
 Pig. 2551, elevation of the mill. 
 
 A, crane for lifting the work. 
 
 B, driver of boxing-shaft. 
 
 C, skeleton-frame to support cylinder. 
 
 D, frame to support upper end of cylinder. 
 
 E, horizontal chucking-plate. 
 
 F, cone of pulleys. 
 
 a, feed-geering for boring-head. 
 
 Fig. 2552, section. 
 
 E, chucking-plate. 
 
 F, cone of pulleys. 
 
 a, horizontal shaft transferring mo- 
 tion by bevel-pinion to upright shaft b, 
 which drives the chucking-plate by a 
 pinion. 
 
 c, small shaft for feed motion to slide- 
 rest. 
 
 d, grooved pulleys for feed motion to 
 the same. 
 
 e, expansion connection with univer- 
 sal joints at each end to convey motion 
 of worm and rack to upright man- 
 drel L 
 
 f brace to support counterbalance 
 geering g. 
 
 h, cone supporting counterbalance. 
 
 i. hexagon mandrel counterbalance. 
 
 Fig. 2554. G, cast-iron frame to sup- 
 port upper end of boring-shaft. 
 
 Fig. 2555 shows the stand or bed 
 indicated by letter C, Fig. 2551, on 
 which the cylinder rests which is to be 
 bored out. 
 
 Fig. 2556 shows a guide, indicated by 
 D, Fig. 2551, which is placed upon top 
 oi cylinder, and serves as guide for bor- 
 ing-bar. The boring-bar is then con- 
 nected to the revolving-plate, as shown 
 
 
 : 
 
 
 
 ! 
 
 ii 
 
 t 
 
204 
 
 LATHE. 
 
 in B and E, Fig. 2551, and turns with it. The boring-head which holds the cutters is shown at G, and it 
 connected with two screws nearly the whole length of boring-bar, set in grooves and moving with the bar 
 and shown by dotted lines, which screws regulate the descent or feed, as it is termed, of the boring-head 
 
 On the upper end of the boring-bar shown at a, Fig. 2552, is placed the geer by which the proper mo- 
 tion is given to the feeding-screws. On the end of each feeding-screw is placed a small pinion, which 
 peers into the inner teeth of a wheel which is loose on the top of boring-bar, and of course does not turn 
 
 2553. 
 
 with it. This wheel has teeth on the inner and outer sides of its periphery ; the outer teeth geer into 
 one of a set of two wheels which turn together, and are placed on a fixed pivot, independent of the 
 boring-bar. The upper wheel of this set geers into the upper wheel a, which is keyed to the boring- 
 
LATHE. 
 
 205 
 
 bar, and of course turns with it. The amount of feed, or the advance of the feeding-screw, is due to the 
 difference of the velocities which are given to the wheels a and m. This difference of the velocities of 
 these two wheels may be varied by varying the diameter of the wheels a and m. 
 
 The geering shown above the top of the boring-bar is for hoisting up the boring-bar, when the ma- 
 cnine is to be used for planing a flat, or taming a cylindrical or conical surface. The machine, aa 
 trranged for this purpose, is shown in Fig. 2552. 
 
 2558. 
 
 The cutting-tool is attached to the bar i, in which a rack is cut, into the teeth of which a pinion geers, 
 which pinion is moved by a perpetual screw on the bar ; by this arrangement the vertical motion is 
 given to the tool. The method of producing the lateral motion of the tool by the screw h is shown by 
 the figure, and does not need explanation. 
 
 Fig. 2557, H, cross-bar and bearing for upper end of shaft of chuck-plate. 
 
20G 
 
 LAP AND LEAD OF THE SLIDE -VALVE. 
 
 2559. 
 
 LAP AND LEAD OF THE SLIDE-VALVE. The slide-valve is that part of a steam-engins 
 which causes the motion of the piston to be reciprocating. It is made to slide upon a smooth surface, 
 called the cylinder face, in which there are three openings to as many pipes or passages : two for the 
 admission of steam to the cylinder, above and below the piston, alternately ; while the use of the third 
 is to convey away the waste steam. The first two are, therefore, termed the induction or steam ports, 
 and the remaining one the eduction or exhaustion port. 
 
 The slide is inclosed in a steam-tight case, called the slide-jacket; and motion is communicated to 
 it by means of a rod working through a stuffing-box. 
 
 The steam from the boilet f.rst enters the jacket, and thence passes into the cylinder, through either 
 steam port, according to the position of the slide, which is so contrived that steam cannot pass from the 
 jacket to the cylinder through both steam ports at the same time, or through the eduction port at any 
 time. 
 
 Case 1. — When a Slide has neither Lead nor Lap . — Fig. 2559 represents the cylinder face for a “ Mur- 
 ray slide” without lap ; a and b being the induction ports, and c the eduction. 
 
 Figs. 2560, 2561, and 2562, are similar sections of the nosle, 
 showing the slide in its central and two extreme positions. It 
 occupies the mid-position, Fig. 2560, when the piston is at either 
 extremity of its stroke ; the extreme position, Fig. 2561, when 
 the piston is at half stroke in its descent ; and that shown in Fie. 
 
 2562, when the piston is at half-stroke in its ascent. 
 
 When a slide has no lap, the width of its facing, at/ and j, 
 
 Fig. 2560, equals that of the steam ports ; the lap being any 
 additional width 'whereby those ports are overlapped. 
 
 That the waste steam may have unobstructed egress, the ex- 
 haustion port c must be made of no less width than the steam ports ; and, for the same reason, the bars 
 d and e should correspond with the slide face at / and g. The three ports, together with the bars be- 
 tween and beyond them, are therefore drawn of equal width ; the total length of the slide being equal 
 to the distance between the steam sides of the steam ports. 
 
 The distance through which the slide moves, in passing from one extreme position to the other, is 
 called its travel ; which, in this case, equals twice the port. 
 
 When the motion of a slide is produced by means of an eccentric, keyed to the crank-shaft and re- 
 volving with it, the relative positions of the piston and slide depend upon the relative positions of tha 
 crank and eccentric. 
 
 ra 
 
 d 
 
 L_l_] 
 
 Demonstration. 
 
 2503. 
 
 Let ab, Fig. 2563, represent the crank; then b being the crank-pin, and a the 
 centre of motion, the larger circle represents the orbit of the crank, and its diame- 
 ter b c the stroke of the piston. Supposing the cylinder to be an upright one, hav- 
 ing the crank-shaft immediately above or below it, the connection between the pis- 
 ton-rod and crank being merely a connecting-rod, without the intervention of a 
 beam, it is evident that when the position of the crank is a b, the piston will be at 
 the top of the cylinder, and at the bottom when its position is a c. The relative po- 
 sitions of the crank and piston, at any point of the stroke between the two extremes, 
 depend upon the length of the connecting-rod : for the present, however, let us sup- 
 pose the connecting-rod to be of infinite length, and therefore always acting upon 
 the crank in parallel lines, so that when the crank is at d, e will be the apparent position of the piston, 
 and /the same when the crank is at g ; the piston being represented by the sine of the arc described 
 by the crank from either of the points b and c, in the direction of the arrow. 
 
 'The diameter h i, of the inner circle of the figure, represents the travel of the slide, and its radius 
 the eccentricity of the eccentric ; or, regarding the eccentric as a crank, the radius may be said to rep- 
 resent that crank, as a b represents the main crank. The travel of a slide, without lap, being equal to 
 twice the port, the two steam ports are represented by the spaces a h and a i, but transposed, a i being 
 the passage to the top of the cylinder, and a h that to the bottom. 
 
 Supposing the piston to be at b, (the top of the cylinder,) the position of the slide will be that shown 
 in Fig. 2560, the direction of its motion being downward, so that the port a. Fig. 2560, or a i in Fig. 
 2563, may be gradually opened for the admission of steam above the piston, until the pi: ton has 
 arrived at half-stroke, when it will be fully open, as shown in Fig. 2561. The direction of th ) slide’s 
 motion is then reversed, so that when the piston has completed its descent, the port b, Figs 2559 to 
 2562, or ah in the diagram, will begin to open for the admission of steam beneath it, and exhaustion 
 will commence from above it through the port a, or a i, and exhaustion port c, the slide beii g again 
 brought into its central position, Fig. 2560. 
 
 Now the slide being at half-stroke, when the piston is at either extremity of its stroke, if wo make 
 a b the position of the crank, a k will be that of the eccentric ; and the axis of the crank being likewise 
 that of the eccentric, they must necessarily revolve in equal times, and always at the same distance 
 apart ; therefore, when the crank has reached the point d (supposing it to move in the direction of the 
 arrow) the eccentric will have advanced to I, and e d and l m represent the positions of the piston and 
 slide respectively; showing, that when the piston has descended to e, the steam port ai , Fig. 2563, 
 or a, Figs. 2559 to 2562, will be open to the extent am. Again, when the crank is at n, and the piston 
 consequently at half-stroke, a i will be the position of the eccentric, the port a i being fully open, and 
 the slide occupying the extreme position shown in Fig. 2561. The direction of the slide’s motion is now 
 reversed, and the port is again gradually covered by the slide face until the positions of the crank and 
 eccentric are ac and ao, when the piston will have completed its descent, and the port ai will be com- 
 pletely closed, the slide being again brought into its central position, Fig. 2560. The opposite stearr 
 
LAP AND LEAD OF THE SLIDE-VALVE. 
 
 207 
 
 port a h now begins to open for the admission of steam, and the direction of the piston’s motion is re- 
 versed ; the port continues to open until the crank and eccentric reach the points p and h, when the 
 piston will again be at half-stroke, and the slide in its extreme position, Fig. 2562. Meanwhile, exhaus- 
 tion from above the piston has been taking place, to the same extent, through the port a i. Finally, the 
 piston having completed its ascent, the slide again occupies its original position, Fig. 2560, and, its 
 course being downward, steam is again admitted into the cylinder, through the port a ; the piston then 
 begins to descend, and, at the same instant, exhaustion ceases from above, and commences from below 
 it, through the port b. 
 
 It is sometimes urged against the use of the eccentric, as a means of actuating the slide, that the 
 steam ports are opened and closed too slowly ; but it must be remembered that the piston does not 
 move at a uniform velocity, as the crank does ; for example, while the crank describes the arc b d, the 
 piston descends only from b to e, the versed sine of that arc ; and its velocity is gradually increased as 
 it approaches the middle of its stroke, where it is greatest, being equal to that of the crank. Again, as 
 the piston approaches the end of its stroke, its velocity is diminished in the same ratio as that in which 
 it had previously increased, until the completion of its stroke, where it remains stationary during the 
 small space of time in which the direction of its motion is reversed. 
 
 Now, it must be obvious that less steam is required to impel the piston at a slow rate than at a rapid 
 one ; and a glance at Fig. 2363 shows that the steam admitted into the cylinder, when the slide is actu- 
 ated by an eccentric, is at all times proportioned to the velocity of the piston, the port being least open 
 when the piston is near the end of its stroke, and fully open when it is at half-stroke. 
 
 When an eccentric, instead of being set, as in the preceding case, so that the steam port shall only 
 begin to open when the piston commences its stroke, is so placed that the port shall be open to some 
 extent prior to the commencement of the stroke, the width of that opening is termed 
 
 The Lead. — The non-use of lead is disadvantageous, chiefly because at the commencement of every 
 stroke, the steam has to contend with the whole force of that which had impelled the piston during its 
 previous stroke. But besides obviating that disadvantage, the lead is of essential service in locomotive 
 engines, “where it is found necessary to let the steam on to the opposite side of the piston before the 
 end of its stroke, in order to bring it up gradually to a stop, and diminish the violent jerk that is caused 
 by its motion being changed so very rapidly as five times in a second. The steam let into the end of 
 a cylinder before the piston arrives at it, acts as a spring cushion to assist in changing its motion ; and 
 if it were not applied, the piston could not be kept tight upon the piston-rod.” 
 
 Case 2. — When a slide has lead without lap. — Let a b, Fig. 2564, represent the stroke of the piston ; 
 c d the travel of the slide ; and ef the lead; then, supposing the piston to be at the top of the cylinder, 
 ea is the position of the crank, and eg that of the eccentric. Following the course 
 of the crank, in the direction of the arrow, we find tire port e d fully open, not, as in 
 the former case, when the piston is at half-stroke, but when it has descended to the 
 point k, — the arc a i, described by the crank, being equal to the arc g d, described 
 by the eccentric. Again, we find the port reclosed when the piston has descended 
 to i', at which point exhaustion commences from above the piston through e d, and 
 steam enters belov it through e c, for the return stroke, at the commencement of 
 which the port e c is open to the extent e l (equal to cf) for the admission of steam, 
 while e d is open to the same extent for exhaustion. 
 
 It is to be remarked, that the amount of lead is necessarily very limited in prac- 
 tice, its tendency being to arrest the progress of the piston before the completion of its stroke. Tho 
 greatest possible amount of lead equals half the travel of the slide. The eccentric would in that case 
 be set diametrically opposite to its first position, which would have the effect of reversing the direction 
 of the piston’s motion. 
 
 In the case of a slide having lead without lap, the distance of a piston from the end of its stroke, 
 when the lead produces its effect, is proportional to the lead as the versed sine of an arc is to its sine, 
 supposing the radii of the crank and eccentric to be equal. 
 
 Demonstration. 
 
 Let a b, Fig. 2565, represent both the travel of the slide and the piston’s stroke; 2565. 
 
 then c a and c b represent the steam ports. And let c d represent the lead ; then c a 
 and ce represent the crank and eccentric, the piston being at the top of the cylinder. 
 
 Now, steam will enter the cylinder, below the piston, when the eccentric is at f and 
 the crank at g ; for the arcs a eg, and c bf are equal. Again, the arc g b is equal to 
 h e ; therefore, i g is equal to k e, and i b to k h. Now, k e is the sine of the arc li e, 
 and k h (equal to i b) is its versed sine : hence 
 
 Rule I. — To find the distance of the piston from the end of its stroke, when the 
 lead produces its effect : — Divide the lead by the width of the steam port, both in inches, and call the 
 quotient sine ; multiply its corresponding versed sine, found in the table, by half the stroke, and the 
 product will be the distance of the piston from the end of its stroke, when steam is admitted for the 
 return stroke, and exhaustion commences. Or, 
 
 Rule II. — To find the lead, the distance of the piston from the end of its stroke being given : — Divide 
 the distance in inches by half the stroke in inches, and call the quotient versed sine ; multiply its cor- 
 responding sine by the width of steam port, and the product will be the lead. 
 
 Example l.--The stroke of a piston is 48 inches ; width of steam port 2^ inches ; and lead l inch r 
 required the distance of the piston from the end of its stroke, when exhaustion commences. 
 
 Here, -5 ~ 2'5 — -2 = sine ; and versed sine of sine '2 = '0202. 
 
 Then, -0202 X 24 ;= -4848 inches. 
 
208 
 
 LAP AND LEAD OF THE SLIDE-VALVE. 
 
 Example 2. — The stroke of a piston is 48 inches ; width of steam port 25 inches ; and distance o* 
 piston from the end of its stroke, when exhaustion commences, -4848 inches : required the lead. 
 
 Here, -4848 — 24 = -0202 = versed sine ; 
 and sine of versed sine '0202 = - 2. 
 
 Then, -2 X 2 5 = '5 =lead. 
 
 When the lead of a slide is equal to the widtli of steam port multiplied by any number in the first 
 column of the following table, the distance of the piston from the end of its stroke, when steam is 
 admitted on the exhaust-side, will be equal to half the stroke multiplied by the corresponding number 
 of the second column. Or, if the distance of the piston from the end of its stroke, when steam is ad- 
 mitted on the exhaust-side, be equal to half the stroke multiplied by any number in the second column, 
 the width of steam port multiplied by the corresponding number of the first column equals the lead. 
 
 When the lead is equal to 
 the width of steam port 
 multiplied by 
 
 0625 
 
 
 ('•0019 
 
 09375 
 
 
 ■0044 
 
 125 
 
 
 •0078 
 
 1875 
 
 
 •0176 
 
 21875 
 
 The distance of the piston 
 
 ■0242 
 
 25 
 
 from the end of its stroke, 
 
 •0317 
 
 28125 
 
 when steam is admitted _ 
 
 •0403 
 
 3125 
 
 on the exhaust-side, 
 
 •0501 
 
 34375 
 
 equals half the stroke 
 
 •0609 
 
 375 
 
 multiplied by 
 
 •0730 
 
 40625 
 
 
 •0862 
 
 4375 
 
 
 •1008 
 
 46875 
 
 
 •1166 
 
 5 
 
 
 T339 
 
 The Lap. — A slide is said to have lap when the width of its face is greater than that of the steam 
 ports, the ports being thereby overlapped, as in Fig. 2569. 
 
 It is to be remarked that slides should have some degree of lap on both the steam and exhaustion 
 sides of the passage, because, although in theory an aperture may be said to be completely closed when 
 covered by a bar of similar width, yet, in the construction of a slide without lap, we cannot insure such 
 accuracy of Jit as to preclude the possibility of steam entering or leaving both steam ports at the san 
 time. 
 
 Lap on the steam side has the effect of cutting off the steam from the cylinder, by closing the pon 
 before the completion of the stroke, the remainder of the stroke being effected by the expansion of the 
 steam already admitted. 
 
 Demonstration. 
 
 Case 3. — When a slide has lap on the steam sick, without lead . — Let ah and he, Fig. 2566, represent 
 the lap at both ends of the slide ; and let a d and c e represent the two steam ports ; then d e will repre- 
 sent the travel of the slide, which, in this case, equals twice the steam port, plus twice the lap. 
 
 Supposing d e also to represent the stroke of the piston, and that the piston is on the top stroke, then 
 b d and bf are the respective positions of the crank and eccentric ; for the slide, instead of occupying 
 its central position, when the piston is at the end of its stroke, (as in Case 1,) must be set in advance of 
 that position to the extent of the lap, that steam may enter the cylinder when the piston begins to 
 move. See Fig. 2567. 
 
 When the eccentric has advanced from f to e, the crank will have reached the point g ; the piston is 
 therefore at a when the port c e is fully open, the slide being then in the position Fig. 2568. Again, 
 when the eccentric has reached the point h, the port c e will be reclosed. Fig. 2567, and i will be the 
 position of the piston ; therefore, the distance of the piston from the end of its stroke, when the steam is 
 cut off, is proportioned to the whole stroke, as i e is to d e. 
 
 When the eccentric arrives at k, the slide will occupy its central position, Fig. 2569, and the piston 
 will be at in, vjhere exhaustion commences from above it ; but steam is not admitted below it, for the 
 return stroke, until the eccentric has reached the point n, where the port o d begins to open, the position 
 of the slide at that moment being that shown in Fig. 2570. 
 
 When the eccentric arrives at d, the port will be fully open, the slide being then in its extreme posi- 
 tion, Fig. 2571 ; and it will be reclosed when the eccentric arrives at g, and the piston at p, where the 
 steam is cut off, the position of the slide being again that shown in Fig. 2570. Again, when the eccen- 
 
LAI' AND LEAD OF THE SLIDE-VALVE. 
 
 209 
 
 trie reaches the point r, exhaustion ceases from above the piston, which is then at s, and commences 
 from below it, the slide being then in its central position, Fig. 2569, and moving downward. Finally, 
 the crank having arrived at d, and the eccentric at/, the piston will have completed its ascent, and the 
 slide will occupy the position, Fig. 2567, as at starting. 
 
 The steam was shown to be cut off when the piston had descended from d to i, the crank having 
 described the arc dgu, and the eccentric the arc fell. Now, di is the versed sine of dgu, and ec is 
 the versed sine of half fe h ; and dgu and f e h are equal arcs. Hence 
 
 Rule III. — To find at what part of the stroke steam will be cut off with a given amount of lap : — 
 Divide the width of steam port, by itself, plus the lap, and call the quotient versed sine. Find its cor 
 responding arc in degrees and minutes, and call it arc the first. If arc the first be less than 45 degrees, 
 multiply the versed sine of twice that arc by half the stroke in inches, and the product will be the Jis 
 tance of the piston from the commencement of its stroke, when the steam is cut off. 
 
 If arc the first exceed 45 degrees, multiply the versed sine of the difference between double that arc 
 and 180 degrees by half the stroke, and the product will be the distance of the piston from the end of 
 its stroke when the steam is cut off. 
 
 Rule IV. — To find the amount of lap necessary to cut off the steam at any given part of the stroke : — 
 
 If it be required to cut off the steam before half-stroke, divide the distance the piston moves before 
 steam is cut off, by half the stroke, and call the quotient versed sine. Find the arc of that versed sine, 
 and also the versed sine of half that arc. Divide the difference between the versed sine last found and 
 unity, by the versed sine, and multiply the width of steam port by the quotient ; the product will be 
 the lap. 
 
 If if be required to cut off the steam at a point beyond half-stroke, divide the distance of the piston 
 from the end of its stroke, when steam is cut off, by half the length of stroke ; call the quotient versed 
 sine; find its corresponding arc, and abstract it from 180 degrees. Find the versed sine of half the 
 remainder, and subtract it from unity. Divide the remainder by the versed sine, and multiply the 
 width of the steam port by the quotient ; the product will be the lap. 
 
 Example 3. — The stroke of a piston is 36 inches; width of steam port 1-J- inch ; and lap 6 inches : 
 required the point of the stroke at which steam will be cut off. 
 
 Here T5 -f- 6 ==7'5 ; and T5 ~ 7'5 —-2 — versed sine; 
 
 arc of vereed sine ’2 = 36° 52', (arc the first ;) 
 and 36° 52' X '2 = 73° 44' = are of versed sine, '7198. 
 
 Then - 7198 X 18 == 12'95 inches = distance of the piston from the commencement of its stroke when 
 the steam is cut off. 
 
 Example 4 . — The stroke of a piston is 36 inches ; width of steam port 1 ^ inch ; and extent of lap l} 
 inch : required the point of the stroke at which steam is cut off. 
 
 Here 1'5 -f- T25 =: 2'75 ; and 1-5 —• 2'75 = '5454 = versed sine of arc 62° 58' (arc the first.) 
 
 Then 62° 58' X 2 = 125° 56' ; and 180° -125° 56' = 54° 4' = arc of versed sine, -4131; '4131 X 
 18 = 7'43 inches = distance of the piston from the end of its stroke when the steam is cut off. 
 
 Example 5.— The stroke of a piston is 36 inches ; width of steam port T5 inches ; and distance of the 
 piston from the commencement of its stroke, when che steam is cut off, 12'95 inches : required the lap. 
 Here 12'95 -fr 18 = -7198 = versed sine of arc 73° 44' ; 
 
 * 73° 44' -7- 2 = 36° 52' = arc of versed sine - 2. 
 
 Then 1 — '2 = - 8 ; and '8 -f • 2 — 4 ; T5 X 4 = 6 inches = lap. 
 
 The Lead and Lap. — H aving separately investigated the two cases of a slide having lead without 
 lap, and lap without lead, we now proceed to consider the effect of both in combination, together with 
 that of lap on the exhaustion side. 
 
 Demonstration. 
 
 Case 4.— When a slide has lap on both the steam and exhaustion sides, together with lead. — Let 
 a b and a c, Fig. 2572, represent the double lap on the steam side; af 
 and a g, the same on the exhaustion side ; b e and c, d the steam ports ; 
 and the line ed both the travel of the slide and stroke of the piston. 
 
 Then, supposing c h to represent the lead of the slide, a i will be the po- 
 sition of the eccentric when that of the crank is ae\ the slide occupving 
 the position shown in Fig. 2573, and the piston being at the top of its 
 downward stroke. 
 
 When the eccentric reaches the point k, the port c d will be fully closed, 
 as shown in Fig. 2574, and the piston will have descended to l, the arc 
 e m being equal to the arc i k. Again, when the eccentric arrives at n, 
 the slide being then brought into the position Fig. 257 5, exhaustion com- 
 mences from above the piston, which has descended to o ; the arc e mp 
 being equal to the arc i k n. When the eccentric arrives at q, the port b t 
 begins to open for the admission of steam beneath the piston, (see Fig. 
 
 2576,) which has then descended to r; the arc eins being equal to the 
 arc ikq. When the eccentric has reached the point i ', opposite to i, the port be will be open to the 
 extent of the lead b h', equal to c h, and the piston will have completed its descent. 
 
 Steam continues to enter the port b e during the ascent of the piston, until the eccentric reaches the 
 point k', when the port b e will be reclosed, Fig. 257 6, the direction of the slide’s motion being 
 downward, and the piston having ascended to V. Exhaustion ceases from above the piston when the 
 eccentric reaches the point t, the piston being then at u, and the slide again in the position Fig. 2575. 
 
 Von. _ II. — 11 
 
 2572. 
 
■210 
 
 LAP AND LEAD OF THE SLIDE-VALVE. 
 
 
 When the eccentric reaches (lie point n', opposite to n, exhaustion commences below the piston, the 
 slide being then in the position Fig. 2577, and the piston at o'. Finally, when the eccentric reaches 
 the point q', and the crank the point s', opposite to s, steam 
 begins to enter the port ccl for the return stroke, at the com- 
 mencement of which the port c d will be open to the extent 
 of the lead c h ; the crank and eccentric occupying their original 
 positions a e and a i. 
 
 It is here shown that four distinct circumstances result from 
 the use of a slide having lap on both sides of the port, with 
 lead, during a single stroke of the piston. These are — 
 
 First : The cutting off the steam, for the purpose of expan- 
 sion. 
 
 Second: The cessation of exhaustion on the exhaustion side. 
 
 Third: The commencement of exhaustion on the steam side. 
 
 Fourth : The readmission of steam for the return stroke. 
 
 With regard to the first of these results, we found the steam port cd closed, when the crank and 
 eccentric had described the equal arcs e m and i dk. Now, c d , the steam port, is the versed sine of d k ; 
 and h d , the steam port minus the lead, is the versed sine of i d. Hence, 
 
 Rule V. — To find the point of the stroke at which steam will be cut off : 
 
 Divide the width of the steam port, and also that width minus the lead, by half the slide’s travel, and 
 call the quotients versed sines. Find their corresponding arcs, and call them arc the first, and arc the 
 second, respectively. 'Then, if the sum of those arcs be less than 90 degrees, multiply the versed sine 
 of their sum by half the stroke, in inches, and the product will be the distance of the piston from the 
 commencement of its stroke, when the steam is cut off. 
 
 If the sum of arcs the first and second exceed 90 degrees, subtract it from 180 degrees; and the 
 versed sine of the difference, multiplied by half the stroke, equals the distance of the piston from the 
 end of its stroke, when the steam is cut off. 
 
 Example 8. — The stroke of a piston is 60 inches ; the width of steam port 8 inches ; lap on the steam 
 side 2£ inches ; lap on the exhaust side £th inch ; and lead -J- inqb : required the point of the stroke at 
 which steam will be cut off. 
 
 2573. 2574. 2575. 2576. 2577. 
 
 Here 
 
 3 
 
 3 + 2-5 
 
 •5454 = versed sine of 62° 58' (arc the first;) 
 
 3— -5 
 
 and = -4545 = versed sine of 56° 57' (arc the second.) 
 
 Then 62 c 58' + 56° 57' = 119° 55'; and 180° — 119° 55' = 60 5' = arc of versed sine, -5012. 
 •5012 X 30 = 15-036 inches = distance of the piston from the end of its stroke when the steam is cut off. 
 
 Exhaustion was shown to cease, during the ascent of the piston, when the eccentric had reached the 
 point t, and the crank the point x ; the crank having described the arc dk x, equal to i' e t described by 
 the eccentric. 
 
 Now i' e is equal to arc the second, (Rule V. ;) and e t is equal to 90 degrees minus 1 1\ or the arc ol 
 versed sine ef; and e f is half the slide’s travel minus the lap on the exhaust side. Hence, 
 
 To find the point of the stroke at which exhaustion ceases : . 
 
 Divide half the slide’s travel, minus the exhaustion lap, by half the travel, call the quotient versed 
 eine, and add its corresponding arc, calling it arc the third, to arc the second. The versed sine of the 
 difference between their sum and 180 degrees, multiplied by half the stroke, equals the distance of the 
 piston from the end of its stroke when exhaustion ceases. 
 
 Example 9. — The several proportions being as in the preceding example. 
 
 Here 3 + 2-5 = 5 -5 = half the slide’s travel ; 
 
 5'5 — T25 
 
 and — = '9772 = versed sine of arc 88° 42' = (arc the third.) 
 
 oo v 
 
 Then 83° 42' + 56° 57' (arc the second) = 145° 39'; and 180° — 145° 39 ' = 34° 21' = arc ot 
 versed sine, T743. T743 X 30 = 5 p 229 inches =the distance of the piston from the end of its stroke 
 when exhaustion ceases. 
 
 Exhaustion was shown to commence from above the piston when the crank and eccentric had de- 
 scribed the equal arcs e k' p and idn. 
 
 Now i d n is equal to 1 80 degrees minus ni' ; n i' is equal to n' i ; and n' d is equal to arc the third. 
 Hence, 
 
 To find the distance of the piston from the end of its stroke when exhaustion commences : 
 
 Subtract arc the second from arc the third, and multiply the versed sine of their difference by half the 
 stroke. The product will be the distance required. 
 
 Example 10. — 'The proportions being as in the two preceding examples. 
 
 Here 88° 42' — 56° 57' =31° 45'=arc of versed sine, ‘1496; and T496 X 30 = 4’488 inches, the 
 distance required. 
 
 Steam was found to be readmitted, for the return stroke, when the piston had reached the point r 
 tn its descent, the crank and eccentric having described the equal arcs e k' s and i d q. 
 
 Now i dq is equal to 180 degrees minus q V ; i' being diametrically opposed to i. And q V is equal 
 to i q', the difference between arcs the first and second. Hence, 
 
 To find the distance of the piston from the end of its stroke when steam is readmitted for the returr 
 -troke 
 
LAP AND LEAD OF THE SLIDE-VALVE. 
 
 211 
 
 Multiply the versed sine of the difference between arcs the first and second by half the stroke, and 
 the product will be the distance required. 
 
 Example 11. — The proportions being as before. 
 
 Here 62° 58' — 56° 57' = 6° 1 ' = arc of versed sine '0055. 
 
 Then '0055 X 30 = '165 inches = the distance required. 
 
 RuleVI.-^ To find the proportions of the steam lap and lead ; the points of the stroke where steam is 
 cut oftl and readmitted for the return stroke, being known : 
 
 When the steam is cut off before half-stroke, divide the portion of the stroke performed by the piston 
 by half the stroke, and call the quotient versed sine. Likewise, divide the distance of the piston from 
 the end of its stroke when steam is readmitted for the return stroke, by half the stroke, and call that 
 quotient versed sine. Find their respective arcs, and also the versed sines of half their sum and hall 
 their difference. The width of the steam port in inches, divided by the versed sine of half their sum, 
 equals half the travel of the slide : and half the travel, minus the width of port, equals the lap. The 
 difference of the two versed sines last found, multiplied by half the travel of the slide, equals the lead. 
 
 When the steam is to be cut off after half-stroke, divide the distance of the piston from the end of its 
 stroke by half the stroke ; call the quotient versed sine, and subtract its corresponding arc from 180 
 degrees. Divide the distance the piston has to move when the steam is admitted for the return stroke, 
 by half the stroke ; call the quotient versed sine, and find its corresponding arc. Then proceed with the 
 two arcs thus found, as in the former case. 
 
 Example 12. — The stroke of a piston is 60 inches ; the width of steam port 3 inches ; distance of the 
 piston from the end of its stroke when steam is cut off 15'036 inches ; and when steam is admitted for 
 the return stroke T65 inches: required the lap and lead. 
 
 Here 15'036 = 30 = '5012 = versed sine of arc 60° 5' ; 
 and 180° — 60° 5' = 119° 55'. 
 
 Then T65 -f- 30 = '0055 = versed sine of 6° 1*. 
 
 119° 55' + 6° 1' = 125° 56'; 119° 55' — 6° l' = 113° 54'. 
 
 1 OSO K Cl 
 
 — = 62° 58' = arc of versed sine '5454 ; 
 
 o 
 
 113° 54' 
 
 ■ — p = 56° 67' = arc of versed sine ’4545. 
 
 3 -i- '5454 = 5'5 inches = half the slide’s travel ; 
 and 5'5 — 3 = 2'5 = lap. 
 
 '5454 — '4545 = '0909 ; and '0909 X 5'5 = '5 inches = lead. 
 
 To find the lap and lead by construction. 
 
 The stroke of the piston ; width of steam port ; and distances of the piston from the end of its stroke 
 when the steam is cut off, and when it is readmitted for the return stroke, being known : 
 
 Let the circle, Fig. 2578, represent the crank’s orbit, and its diameter a b the stroke of the piston, to 
 some known scale. Make a c equal to the part of (he stroke performed 
 before the steam is cut off; and b d equal to the distance, of the piston 
 from the end of its stroke when steam is readmitted for the return stroke. 
 
 Draw d e and ef at right angles to a b, and mark the point g at the dis- 
 tance be from/. Bisect the arc ag, and from the point of bisection, h, 
 draw the diameter h i. Make ik equal to b e ; draw i m and kl at right 
 angles to a b ; and draw * l and i b indefinitely. From the point m set off 
 m n equal to the width of steam port, full size ; from n draw n o parallel 
 to i m, and meeting i b, and also op parallel to a b, and meeting h i ; then 
 will sp equal the lap, and s r the lead. 
 
 In all the foregoing cases, we have taken the versed sine of the arc de- 
 scribed by the crank, from either extremity of the stroke, as the portion 
 of the stroke performed by the piston ; but, as has been already observed, 
 the relative positions of the piston and crauk depend upon the length of 
 the connecting-rod, which will be seen by reference to Fig. 2579, where 
 A B represents the stroke of the piston, C D the connecting-rod, and D 0 the crank. Now, by supposing 
 a d to be the arc described by the crank when the piston has performed one-fourth of its stroke, and 
 from the length of that arc, calculating the amount of lap re- 
 quired to cut off the steam at that part of the stroke, we appear 
 to be in error— for, from the oblique action of the connecting-rod, 
 the piston would have descended only to the point c. But the 
 engine being double-acting, we have to take into consideration 
 the position of the crank when the piston has performed one- 
 fourth of its stroke in the opposite direction from the point B ; 
 and here we find, that by supposing the crank to have described 
 the arc b e, (equal to a d,) instead of the true arc b E, we cause 
 the steam to be cut off when the piston has reached the point/ ; 
 and the distance B / being precisely as much more than B F as A c is less than A C, the seeming error 
 is self-corrective. 
 
 2579. 
 
212 
 
 LEAD. 
 
 A Table of Multipliers to find the Lap and Lead, when the Steam is to be cut off at \ to |(/u 
 
 of the Stroke. 
 
 The lap must be equal to the width of the steam port multiplied by col. 1. 
 
 The lead must be equal to the width of the steam port multiplied by col. 2. 
 
 Half-Stroks. 
 
 Five-Eighths 
 of the Stroke. 
 
 Three-Fourths 
 of the Stroke. 
 
 Seven-Eighths 
 of the Stroke. 
 
 
 
 1 
 
 2 
 
 i 
 
 2 
 
 1 
 
 2 
 
 i 
 
 2 
 
 
 
 Lap 
 
 2-41 
 
 Lead 
 
 *000 
 
 Lap 
 
 1-58 
 
 Lead 
 
 •ooo 
 
 Lap 
 
 1.000 
 
 Lead 
 
 ■ooo 
 
 Lap 
 
 •540 
 
 Lead 
 
 •ooo 
 
 3§£ 
 
 •ooooo 
 
 2T6 
 
 •145 
 
 T41 
 
 T24 
 
 •893 
 
 T05 
 
 •477 
 
 •089 
 
 op-g 
 
 •00208 
 
 206 
 
 •198 
 
 T35 
 
 T70 
 
 •851 
 
 T46 
 
 •450 
 
 T23 
 
 3 ,3, 
 
 •00416 
 
 T94 
 
 •268 
 
 1-27 
 
 •231 
 
 •795 
 
 •200 
 
 •413 
 
 T70 
 
 § !| 
 
 ■00833 
 
 1-8-1 
 
 •318 
 
 1-21 
 
 •276 
 
 ■754 
 
 •240 
 
 ■385 
 
 •204 
 
 
 •01250 
 
 T77 
 
 •358 
 
 TIG 
 
 •312 
 
 ■723 
 
 •271 
 
 ■363 
 
 ■232 
 
 •01666 
 
 1-71 
 
 •391 
 
 112 
 
 ■342 
 
 •691 
 
 •299 
 
 ■344 
 
 ■257 
 
 2 
 
 ■02083 
 
 1-65 
 
 •420 
 
 T08 
 
 •368 
 
 •66S 
 
 ■322 
 
 •327 
 
 ■277 
 
 5 1 ; 
 11? 
 
 •02500 
 
 1-60 
 
 ■444 
 
 T05 
 
 •391 
 
 •644 
 
 •343 
 
 •313 
 
 ■296 
 
 •02916 
 
 1-56 
 
 •467 
 
 T02 
 
 •412 
 
 •623 
 
 •362 
 
 •298 
 
 •313 
 
 •03333 
 
 T48 
 
 •505 
 
 •968 
 
 •449 
 
 •586 
 
 •396 
 
 •273 
 
 ■343 
 
 O M- 
 
 — o 
 
 •04166 
 
 1-41 
 
 •540 
 
 •921 
 
 ■480 
 
 •554 
 
 •425 
 
 •251 
 
 •370 
 
 
 •05000 
 
 1'35 
 
 ■570 
 
 •881 
 
 ■508 
 
 •526 
 
 •451 
 
 •232 
 
 ■393 
 
 ° g 1 
 
 •05833 
 
 1-30 
 
 ■595 
 
 ■844 
 
 •532 
 
 500 
 
 •473 
 
 •215 
 
 •414 
 
 8 Z 
 
 Ilf 
 
 •06666 
 
 T25 
 
 •617 
 
 •810 
 
 •554 
 
 ■476 
 
 •495 
 
 T98 
 
 •434 
 
 •07500 
 
 1-21 
 
 ■638 
 
 ■779 
 
 •572 
 
 •454 
 
 •514 
 
 T83 
 
 ■452 
 
 
 •08333 
 
 1.17 
 
 •657 
 
 •751 
 
 •592 
 
 ■434 
 
 •532 
 
 T60 
 
 •468 
 
 
 ■09166 
 
 1-13 
 
 •674 
 
 •724 
 
 •607 
 
 •415 
 
 ■648 
 
 T56 
 
 •483 
 
 
 •10000 
 
 Example of its application. — Stroke 36 inches ; width of port 2 inches ; steam to be cut off at half- 
 stroke ; distance of the piston from the end of its stroke when steam is readmitted for the return stroke* 
 To inch. 
 
 1-5 
 
 — = 0833. Find that number, or the one nearest to it, in the right hand, or last column, and take 
 out the multipliers on the same line under the head. Half-stroke. 
 
 Then 2 X T21 = 2’42 inches = the lap. 
 
 And 2 X '638 = T276 inches = the lead. 
 
 LEAD — A well-known metal much used in the arts. Lead unites with most of the metals, has little 
 elasticity, and is the softest of them all. Gold and silver are dissolved by it in a slight red heat, but 
 when the heat is much increased the lead separates, and rises to the surface of the gold, combined with 
 all heterogeneous matters ; hence lead is made use of in the art of refining the precious metals. If lead 
 be heated so as to boil and smoke, it soon dissolves pieces of copper thrown into it ; the mixture, when 
 cold, being brittle. The union of these two metals is remarkably slight, for upon exposing the mass to 
 a heat no greater than that in which lead melts, the lead almost entirely runs off by itself. 
 
 Among the ores of lead some have a metallic aspect ; are black in substance, as well as when pulver- 
 ized ; others have a stony appearance, and are variously colored, with usually a vitreous or greasy 
 lustre. The specific gravity of the latter ores is always less than 5. The whole of them, excepting the 
 chloride, become more or less speedily black, with sulphureted hydrogen or with hydrosulphurets ; and 
 are easily reduced to the metallic state upon charcoal, with a flux of carbonate of soda, after they have 
 been properly roasted. They diffuse a whitish or yellowish powder over the charcoal, which, according 
 to the manner in which the flame of the blowpipe is directed upon it, becomes yellow or red ; thus 
 indicating the two characteristic colors of the oxides of lead. 
 
 The lead ores most interesting to the arts are : 
 
 1. Galena, sulphuret of lead. This ore has the metallic lustre of lead, with a crystalline structure 
 derivable from the cube. When heated cautiously at the blowpipe it is decomposed, the sulphur flies 
 off, and the lead is left alone in fusion ; but if the heat be continued, the colored surface of the charcoal 
 indicates the conversion of the lead into its oxides. Galena is a compound of lead and sulphur, in equiv- 
 alent proportions, and therefore consists, in 100 parts, of 86| of metal, and 13 j of sulphur, with which 
 numbers the analysis of the galena of Clausthal by Westrumb exactly agrees. Its specific gravity, 
 when pure, is 7-56. Its color is blackish gray, without any shade of red, and its powder is black — char- 
 acters which distinguish it from blende, or sulphuret of zinc. 
 
 2. The seleniuret of lead resembles galena, but its tint is bluer. Its chemical characters are the only 
 ones which can be depended on for distinguishing it. At the blowpipe it exhales a very perceptible 
 smell of putrid radishes. Nitric acid liberates the selenium. When heated in a tube, oxide of selenium 
 sf a carmine red rises along with selenic acid, white and deliquescent. The specific gravity of this ore 
 caries from 6'8 to 7'69. 
 
 3. Native minium or red lead has an earthy aspect, of a lively and nearly pure red color, but some- 
 times inclining to orange. It occurs pulverulent, and also compact, with a fracture somewhat lamellar 
 When heated at the blowpipe upon charcoal, it is readily reduced to metallic lead. Its specific gravity 
 varies from 46 to 8'9. This ore is rare. 
 
LEAD. 
 
 213 
 
 4. Plornb-gomme. — This lead ore, as singular in appearance as in composition, is of a dirty brownish 
 yr orange-yellow, and occurs under the form of globular or gum-like concretions. It has also the lustre 
 and translucency of gum, with somewhat of a pearly aspect at times. It is harder than fluor spar. It 
 oonsists of oxide of lead, 40 ; alumina, 37 ; water, 18'8 ; foreign matters and loss, 406 ; in 100. Hith- 
 erto it has been found only at Huelgoet, near Poullaouen, in Brittany, covering with its tears, or small 
 concretions, the ores of white lead and galena which compose the veins of that lead mine. 
 
 6. White lead , carbonate of lead. — This ore, in it's purest state, is colorless and transparent, like glass, 
 with an adamantine lustre. It may be recognized by the following characters : 
 
 Its specific gravity is from 6 to 6-7 ; it dissolves with more or less ease, and with effervescence, in 
 nitric acid ; becomes immediately black by the action of sulphureted hydrogen, and melts on charcoal 
 before the blowpipe into a button of lead. According to Klaproth, the carbonate of Leadhills contains 
 82 parts of oxide of lead, and 16 of carbonic acid, in 98 parts. This mineral is tender, scarcely scratches 
 calc-spar, and breaks easily, with a waved conchoidal fracture. It possesses the double refracting prop- 
 erty in a very high degree ; the double image being very visible on looking through the flat faces of the 
 prismatic crystals. Its crystalline forms are very numerous, and are referrible to the octahedron, and 
 the pyramidal prism. 
 
 6. Vitreous lead , or sulphate of lead. — This mineral closely' resembles carbonate of lead; so that the 
 external characters are inadequate to distinguish the two. But the following are sufficient. When 
 pure, it has the same transparency and lustre. It does not effervesce with nitric acid; it is but feebly 
 blackened by sulphureted hydrogen , it first decrepitates and then melts before the blowpipe into a 
 transparent glass, which becomes milky as it cools. By the combined action of heat and charcoal, it 
 passes first into a red pulverulent oxide, and then into metallic lead. It consists, according to Klaproth, 
 of 71 oxide of lead, 26 sulphuric acid, 2 water, and 1 iron. That specimen was from Anglesea; the 
 Wanlockhead mineraMs free from iron. The prevailing form of crystallization is the rectangular octa- 
 hedron, whose angles and edges are variously modified. The sulphato-carbonate, aud sulphato tri-car- 
 bonate of lead, now called Leadhillite, are rare minerals which belong to this head. 
 
 7. Phosphate of lead. — This, like all the combinations of lead with an acid, exhibits no metallic lustre, 
 but a variety of colors. Before the blowpipe upon charcoal, it melts into a globule externally crystal- 
 line, which, by a continuance of the heat, with the addition of iron and boracic acid, affords metallic lead. 
 Its constituents are 80 oxide of lead, 18 phosphoric acid, and T6 muriatic acid, according to Klaproth's 
 analysis of the mineral from Wanlockhead. The constant presence of muriatic acid in the various 
 specimens examined is a remarkable circumstance. The crystalline forms are derived from an obtuse 
 rhomboid. Phosphate of lead is a little harder than white lead ; it is easily scratched, and its powder is 
 always gray. Its specific gravity is 6'9. It has a vitreous lustre, somewhat adamantine. Its lamellar 
 texture is not very distinct ; its fracture is wavy, and it is easily frangible. The phosphoric and arsenic 
 acids being, according to M. Mitscherlich, isomorphous bodies, may replace each other in chemical com- 
 binations in every proportion, so that the phosphate of lead may include any proportion, from the 
 smallest fraction of arsenic acid to the smallest fraction of phosphoric acid, thus graduating indefinitely 
 into arseniate of lead. The yellowish variety indicates, for the most part, the presence of arsenic acid. 
 
 8. Muriate of lead. Horn-lead, or murio-carbonate. — This ore has a pale yellow color, is reducible to 
 metallic lead by the agency of soda, and is not altered by the hydrosulphurets. At the blowpipe it 
 melts first into a pale yellow transparent globule, with salt of phosphorus and oxide of copper ; and it 
 manifests the presence of muriatic acid by a bluish flame. It is fragile, tender, softer than carbonate of 
 lead, and is sometimes almost colorless, with an adamantine lustre. Specific gravity, 606. Its constit- 
 uents, according to Berzelius, are lead, 25'84; oxide of lead, 67'07 ; carbonate of lead, 6'25-, chlorine, 
 8'84; silica, T46 ; water, 0'54 ; in 100 parts. The carbonate is an accidental ingredient, not being in 
 equivalent proportion. Klaproth found chlorine, 13'67 ; lead, 39'98 ; oxide of lead, 22'57 ; carbonate of 
 lead, 23 78. 
 
 9. Arseniate of lead. — Its color of a pretty pure yellow, bordering slightly on the greenish, and its 
 property of exhaling by the joint action of fire and charcoal a very distinct arsenical odor, are the only 
 characters which distinguish this ore from the phosphate of lead. The form of the arseniate of lead, 
 when it is crystallized, is a prism with six faces, of the same dimensions as that of phosphate of lead. 
 When pure, it is reducible upon charcoal, before the blowpipe, into metallic lead, with the copious exha- 
 lation of arsenical fumes ; but only in part, and leaving a crystalline globule, when it contains any phos- 
 phate of lead. The arseniate of lead is tender, friable, sometimes even pulverulent, and of specific grav- 
 ity 5-04. That of Johann-Georgenstadt consists, according to Rose, of oxide of lead, 77'5 ; arsenic acid, 
 12-5; phosphoric acid, 7'5, and muriatic acid, T5. 
 
 10. Red lead, or chromate of lead. — This mineral is too rare to require consideration in the present 
 work. 
 
 11. Plomb vauquelinite. Chromate of lead and copper. 
 
 1 2. Yellow lead. Molgbyate of lead. 
 
 1 3. Tungstate of lead. 
 
 Having thus enumerated the several species of lead ore, we may remark that galena is the only one 
 which occurs in sufficiently great masses to become the object of mining and metallurgy. This mineral 
 is found in small quantity among the crystalline primitive rocks, as granite. It is, however, among the 
 oldest talc-schists and clay slates that it usually occurs. 
 
 Treatment of the ores of lead . — The mechanical operations performed upon the lead ores, to bring them 
 to the degree of purity necessary for their metallurgic treatment, may be divided into three classes, 
 whose objects are : 
 
 1. The sorting and cleansing of the ores ; 
 
 2. The grinding ; 
 
 3; The washing, properly so called. 
 
 The apparatus subservient to the first objects are sieves, running buddies, and gratings. The large 
 
214 
 
 LEAD. 
 
 sieves employed for sorting the ore at the mouth of the mine, into coarse and fine pieces, is a wire gauza 
 of iron ; its meshes are square, and an inch long in each side. There is a lighter sieve of wire gauze, 
 similar to the preceding, for washing the mud from the ore, by agitating the fragments in a tub filled 
 with water. But instead of using this sieve, the pieces of ore are sometimes merely stirred about with 
 a shovel, in a trough filled with water. 
 
 The method of sorting and cleansing the ore consists in using a plane surface made of slabs or planks, 
 very slightly inclined forwards, and provided behind and on the sides with upright ledges, the back one 
 having a notch to admit a stream of water. The ore is merely stirred about with a shovel, and exposed 
 on the slope to the stream. For this apparatus, formerly the only one used, the following has been sub- 
 stituted, called the grate. It is a grid, composed of square bars of iron, an inch thick, by from 24 to 32 
 inches long, placed horizontally and parallelly to each other, an inch apart. There is a wooden canal 
 above the grate, which conducts a stream of water over its middle ; and an inclined plane is set beneath 
 it, which leads to a hemispherical basin, about 24 inches in diameter, for collecting the metallic powder 
 washed out of the ore. 
 
 The apparatus subservient to grinding the ore are : 
 
 1. The beater, formed of a cast-iron plate, 3 inches square, with a socket in its upper surface, foi 
 receiving a wooden handle. In some localities crushing cylinders have been substituted for the beater. 
 
 At the mines, the knocker's workshop, or striking floor, is provided either with a strong stool, or a 
 wall 3 feet high, beyond which there is a flat area 4 feet broad, and a little raised behind. On this 
 area, bounded, except in front, by small walls, the ore to be bruised is placed. On the stool, or wall, 
 a very hard stone slab, or cast-iron plate is laid, 7 feet long, 7 inches broad, and 14 inches thick, called 
 a knok-stone. The workmen, seated before it, break the pieces of mixed ore with the beater. 
 
 Crushing machines are in general use in England, to break the mingled ores, which they perform with 
 great economy of time and labor. They have been employed there for nearly forty years. 
 
 This machine is composed of one pair of fluted cylinders, and of two pairs of smooth cylinders, which 
 serve altogether for crushing the ore. The two cylinders of each of the three pairs turn simultaneously 
 in an inverse direction, by means of two toothed- wheels upon the shaft of every cylinder, which work 
 by pairs in one another. The motion is given by a single wafer-wheel. One of the fluted cylinders is 
 placed in the prolongation of the shaft of this wheel, which carries besides a cast-iron toothed-wheel, 
 geared with the toothed-wheels fixed upon the ends of two of the smooth cylinders. Above the fluted 
 cylinders, there is a hopper, which discharges down between them the ore brought, forwards by the wag- 
 ons. These wagons advance upon a railway, stop above the hopper, and empty their contents into it 
 through a trap-hole, which opens outwardly in the middle of their bottom. Below the hopper there is a 
 small bucket called a shoe, into which the ore is shaken down, and which throws it without ceasing upon 
 the cylinders. The sho'e is so regulated that too much ore can never fall upon the cylinders, and ob- 
 struct their movement. A small stream of water is likewise led into the shoe, which spreads over the 
 cylinders, and prevents them from growing hot. The ore, after passing between the fluted rollers, falls 
 upon inclined planes, which turn it over to one or other of the pairs of smooth rolls. 
 
 These are the essential parts of this machine ; they are made of iron, and the smooth ones are case- 
 hardened, or chilled, by being cast in iron moulds. The gudgeons of both kinds move in brass brushes 
 fixed upon iron supports made fast by bolts to the strong wood- work base of the whole machine. Each 
 of the horizontal bars has an oblong slot, at one of whose ends is solidly fixed one of the plummer-blocks 
 or bearers of one of the cylinders, and in the rest of the slot the plummer-block of the other cylinder 
 slides ; a construction which permits the two cylinders to come into contact, or to recede to such a dis- 
 tance from each other as circumstances may require. The movable cylinder is approximated to the 
 fixed one by means of iron levers, which carry at their ends weights, and rest upon wedges susceptible 
 of adjustment. These wedges press the iron bar, and make it approach the movable cylinder by 
 advancing the plummer-block which supports its axis. When matters are so arranged, should a very 
 large or hard piece present itself to one of the pairs of cylinders, one of the rollers would move away and 
 let the piece pass without doing injury to the mechanism. 
 
 Besides the three pairs of cylinders which constitute essentially each crushing machine, there is some- 
 times a fourth, which serves to crush the ore when not in large fragments. 
 
 The stamp-mill is employed in concurrence with the crushing cylinders. It serves particularly to 
 pulverize those ores whose gangue is too hard to yield readily to the rollers, and also those which being 
 already pulverized to a certain degree, require to be ground still more finely. (See Stampers.) 
 
 The sifting meshes of the sieve are made of strong iron wire, three-eighths of an inch square. This 
 sieve is suspended at the extremity of a forked lever, or brake, turning upon an axis by means of two 
 upright arms about 5 feet long, which are pierced with holes for connecting them with bolts or pins, 
 both to the sieve-frame and to the ends of the two branches of the lever. These two arms are made 
 of wrought iron, but the lever is made of wood, as it receives the jolt. Each jolt not only makes the 
 fine parts pass through the meshes, but changes the relative position of those which remain on the wires, 
 bringing the purer and heavier pieces eventually to the bottom. The mingled fragments of galena, and 
 the stony substances lie above them ; while the poor and light pieces are at top. These are first 
 scraped oft) next the mixed lumps, and lastly the pure ore, which is carried to the heap. 
 
 The poor ore is carried to a crushing machine, where it is bruised between two cylinders appropriated 
 io this purpose ; after which it is sifted afresh. 
 
 Washing apparatus. — For washing the ore after sifting it, the machine already described is employed 
 
 Smelting of lead ores. — The lead ores of England were anciently smelted in very rude furnaces, oi 
 iolcs, urged by the natural force of the wind, and were therefore placed on the summits or western 
 slopes of the highest hills. More recently these furnaces were replaced by blast hearths, resembling 
 smiths’ forges, but larger, and were blown by strong bellows, moved by men or water-wheels. The 
 principal operation of smelting is at present always executed there in reverberatory furnaces, and in 
 furnaces similar to those known in France by the name of Scotch furnaces 
 
LEAD. 
 
 215 
 
 The reverberatory furnaces called cupola are now exclusively used in Derbyshire for the smelting ol 
 lead ores. In the works where the construction of these furnaces is most improved, they are interiorly 
 8 feet long by 6 wide in the middle, and 2 feet high at the centre. The lire, placed at one of the 
 extremities, is separated from the body of the furnace by a body of masonry, called the fire-bridge , 
 which is two feet thick, leaving only from 14 to 18 inches between its upper surface and the vault. 
 From this, the highest point, the vault gradually sinks towards the further end, where it stands only 6 
 inches above the sole. At this extremity of the furnace, there are two openings separated by a trian- 
 gular prism oi fire-stone, which lead to a flue, a foot and a half wide, and 10 feet long, which is recurved 
 towards the top, and runs into an upright chimney 55 feet high. The above flue is covered with stone 
 slabs, carefully jointed with fire-clay, which may be removed when the deposit formed under them 
 (which is apt to melt) requires to be cleaned out. One of the sides of the furnace is called the laborers’ 
 side. It has a door for throwing coal upon the fire-grate, besides three small apertures each about 6 
 inches square. These are closed with movable plates of cast-iron, which are taken off when the work- 
 ing requires a freer circulation of air, or for the stirring up of the materials upon the hearth. On the 
 opposite side, called the working side, there are five apertures ; namely, three equal and opposite to 
 those just described, shutting in like manner with cast-iron plates, and beneath them two other open- 
 ings, one of which is for running out the lead, and another for the scoriae. The ash-pit is also on this 
 side, covered with a little water, and so disposed as that the grate-bars may be easily cleared from the 
 cinder slag. 
 
 The hearth of the furnace is composed of the reverberatory furnace slags, to which a proper shape has 
 been given by beating them with a strong iron rake, before their entire solidification. On the laborers' 
 side, this hearth rises nearly to the surface of the three openings, and falls towards the working side, so 
 as to be 18 inches below the middle aperture. In this point, the lowest of the furnace, there is a tap- 
 hole, through which the lead is run off into a large iron boiler, (lea-pan,) placed in a recess left outside 
 in the masonry. From that lowest point, the sole gradually rises in all directions, forming thus an in- 
 side basin, into which the lead runs down as it is melted. At the usual level of the metal bath, there 
 is on the working side, at the end furthest from the fire, an aperture for letting off the slag. 
 
 In the middle of the arched roof there is a small aperture, called the crown-hole , which is covered up 
 during the working with a thick cast-iron plate. Above this aperture a large wooden or iron hopper 
 stands, leading beneath into an iron cylinder, through which the contents of the hopper may fall into the 
 furnace when a trap or valve is opened. 
 
 Roasting . — The ordinary charge of ore for one smelting operation is 20 cwts., and it is introduced 
 through the hopper. An assistant placed at the back doors spreads it equally over the whole hearth 
 with a rake ; the furnace being meanwhile heated only with the declining fire of the preceding operation. 
 No regular fire is made during the first two hours, but a gentle heat merely is kept up by throwing one 
 or two shovelfuls of small coal upon the grate from time to time. All the doors are closed, and the 
 register plate of the chimney is lowered. 
 
 The outer basin in front of the furnace is at this time filled with the lead derived from a former pro- 
 cess, the metal being covered with slags. A rectangular slit, above the tap-hole is left open, and remains 
 so during the whole time of the operation, unless the lead should rise in the interior basin above the 
 level of that orifice ; in which case a little mound must be raised before it. 
 
 The two doors in front furthest from the fire being opened, the head smelter throws in through them, 
 upon the sole of the furnace, the slags swimming upon the bath of lead, and a little while afterwards 
 he opens the tap-hole, and runs off the metallic lead reduced from these slags. At the same time his 
 assistant turns over the ore through the back doors. These being again closed, while the above two 
 front doors are open, the smelter throws a shovelful of small coal or coke cinder upon the lead-bath, 
 and works the whole together, turning over the ore with the paddle or iron oar. About three-quarters 
 of an hour after the commencement of the operation, he throws back upon the sole of the hearth the 
 fresh slags which then float upon the bath of the outer basin, and which are mixed with coaly matter. 
 He next turns over these slags, as well as the ore, with the paddle, and shuts all the doors. At this 
 time the smelter runs off the lead into the pig-moulds. 
 
 The assistant now turns over the ore once more through the back doors. A little more than an hour 
 after the operation began, a quantity of lead, proceeding from the slag last remelted, is run off by the 
 tap ; being usually in such quantity as to fill one-half of the outer basin. Both the workmen then turn 
 over the ore with the paddles, at the several doors of the furnace. Its interior is at this time of a dull 
 red heat: the roasting being carried on rather by the combustion of the sulphurous ingredients, than by 
 the action of the small quantity of coal in the grate. The smelter, after shutting the front doors, with 
 the exception of that next the fire-bridge, lifts off the fresh slags lying upon the surface of the outside 
 bath, drains them, and throws them back into the furnace. 
 
 An hour and a half after the commencement, the lead begins to ooze out in small quantities from the 
 ore ; but little should be suffered to flow before two hours have expired. About this time the two 
 workmen open all the doors, and turn over the ore, each at his own side of the furnace. An hour and 
 three-quarters after the beginning, there are few vapors in the furnace, its temperature being very 
 moderate. No more lead is then seen to flow upon the sloping hearth. A little coal being thrown into 
 the grate to raise the heat slightly, the workmen turn over the ore, and then close all the doors. 
 
 At the end of two hours, the first fire or roasting being completed, and the doors shut, the register is 
 to be lifted a little, and coal thrown upon the grate to give the second fire, which lasts during 25 minutes. 
 When the doors are now opened the inside of the furnace is of a pretty vivid red, and the lead flows 
 dowm from every side towards the inner basin. The smelter, with his rake or paddle, pushes the slags 
 upon that basin back towards the upper part of the sole, and his assistant spreads them uniformly over 
 the surface through the back doors. The smelter next throws in, by his middle door, a few shovelfuls 
 of quick -lime upon the lead-bath. The assistant meanwhile, for a quarter of an hour, works the ore and 
 the slags together through the three back doors, and then spreads them out, while the smelter pushes 
 
216 
 
 LEAD 
 
 the slags from the surface of the inner basin back to the upper parts of the sole. The doors being nor* 
 left open for a little, while the interior remains in repose, the metallic lead, which had been pushed back 
 with the slags, flows down into the basin. This occasional cooling of the furnace is thought to be neces- 
 sary for the better separation of the products, especially of the slags, from the lead-bath. 
 
 In a short time the workmen resume their rakes, and turn over the slags along with the ore. Three 
 hours after the commencement, a little more fuel is put into the grate, merely to keep up a moderate 
 heat of the furnace during the paddling. After three hours and ten minutes, the grate being charged 
 with fuel for the third fire, the register is completely opened, the doors are all shut, and the furnace is 
 left in this state for three-quarters of an hour. In nearly four hours from the commencement, all the 
 doors being opened, the assistant levels the surfaces with his rake, in order to favor the descent of any 
 drops of lead ; and then spreads the slags, which are pushed back towards him by the smelter. The 
 latter now throws in a fresh quantity of lime, with the view, not merely of covering the lead-bath and 
 preventing its oxydizement, but of rendering the slags less fluid. 
 
 Ten minutes after the third tire is completed, the smelter puts a new charge of fuel in the grate, and 
 shuts the doors of the furnace to give it the fourth fire. In four hours and forty minutes from the com- 
 mencement, this fire being finished, the doors are opened, the smelter pierces the tap-hole to discharge 
 the lead into the outer basin, and throws some quick-lime upon the slags in the inner basin. He then 
 pushes the slags thus dried up towards the upper part of the hearth, and his assistant rakes them out 
 by the back doors. 
 
 The whole operation of a smelting shift takes about four hours and a half, or at most five hours, in 
 which four periods may be distinguished. 
 
 1. The first fire for roasting the ores, requires very moderate firing, and lasts two hours. 
 
 2. The second fire, or the smelting, requires a higher heat, with shut doors ; at the end the slags are 
 dried up with lime, and the furnace is also allowed to cool a little. 
 
 3. 4. The last two periods, or the third and fourth fires, are likewise two smeltings or foundings, and 
 differ from the first only in requiring a higher temperature. The heat is greatest in the last. The form 
 and dimensions of the furnace are calculated to cause a uniform distribution of heat over the whole sur- 
 face of the hearth. See article Metallurgy. 
 
 The lead is brought from the smelting works to any place where it is to be manufactured in the form 
 of “ pigs,” each of which is an oblong mass, about three feet long, six inches wide, and weighing about 
 one hundred weight and a half. As for the philosophy of the w T ord “ pig,” applied to the masses of 
 lead, we may remark that it forms another curious instance of the phraseology used in manufacture. 
 It appears that in the iron-manufacture, when the metal flows from the furnace in which it has been 
 reduced from the ore, it passes into a large trough excavated in sand, and from thence into smaller lat- 
 eral channels on each side. This arrangement has been suggestive of a sort of simile : for the larger 
 trough is called by the workmen the “ sow,” and the smaller the “ pigs,” who suck the metal from the 
 “ sow hence proceeded the names of “ sow-metal” and “ pig-metal and hence, in all probability, the 
 name of “ pig” is applied to the saleable masses both of iron and of lead. 
 
 The two principal articles into which lead is manufactured are sheet-lead and water-pipes ; or at least 
 they are the only two which need here be noticed, since the comparatively low temperature at which 
 the metal fuses, and the ease with which it is beaten into various forms, enable the plumber to modify 
 it in various ways. The sheet-lead here spoken of is that with which roofs and terraces are covered, 
 and cisterns lined. It is sometimes made, and used formerly to be wholly made, by pouring the melted 
 metal on a flat surface of sand, in a stratum of any required thickness ; but the more modern method is 
 that of rolling, or “milling,” which we proceed to describe. 
 
 A furnace is provided consisting of a hemispherical melting-pot, four or five feet in diameter, and 
 nearly as much in depth, heated by a fire beneath, and covered with an inclosed cap or chimney reach- 
 ing above the roof of the building, for the purpose of conveying away the deleterious gases engendered 
 during the melting of lead. Into this melting-pot is put about six tons (thirteen thousand pounds) of 
 lead, new and old, which remains there till thoroughly melted. During this time all the impurities, 
 being lighter than the metal, rise to the surface. Immediately adjoining the furnace is a cast-iron frame, 
 called the “ mould,” being a flat vessel about six or seven feet square, and six inches deep. The bottom 
 of this mould is also of iron, and the melted metal is allowed to flow into it from an opened valve near 
 the bottom of the melting-pot. A shoot or trough conveys the metal from the furnace to the mould. 
 The glistening liquid mass soon flows out, to the weight of about ten or eleven thousand pounds, the 
 dross and impurities being for the mast part left behind in the melting-pot. As, however, some impuri- 
 ties or oxidized portions enter the moul 1 a subsequent removal becomes necessary ; and this is effected 
 by drawing the edge of a board carefully over the surface of the hot and liquid metal, the board urging 
 before it all the floating impurities, and leaving a surface very silvery and clear. 
 
 After some hours the mass of lead, technically called a “ plate,” is lifted out of the mould by a pow- 
 erful crane, and placed upon the machine where it is to be rolled into the form of sheets. This machine 
 is very peculiar in its action. It consists of a long frame or bench, about a yard in height, seven or 
 eight feet wide, and probably seventy feet in length. At intervals of every foot or two are transverse 
 rollers, all placed on the same level, so that a heavy body may be rolled from one end of the frame to 
 the other with great facility. About midway along the frame is the milling or rolling machine, con- 
 sisting mainly of two ponderous rollers, between which the lead is passed : these are made of iron, the 
 upper one being fifteen or sixteen inches in diameter, with a weight of three tons, the under one being 
 the same. The two rollers are placed at any required distance apart, the one above the other, and are 
 also made to revolve in either direction. These being the mechanical arrangements, the process of 
 milling proceeds thus : The plate of lead is brought between the rollers, which are opened so as only 
 to receive the lead by compressing it; and the rollers being made to rotate, the plate is drawn in be- 
 tween them. This process is repeated over and over again, the plate passing first from right to left. 
 And then from left to right, the opening between the rollers being gradually reduced bv means of an 
 
LEAD. 
 
 217 
 
 index and graduated dial-plate. The small wooden rollers facilitate the motion of the elongated lead 
 to and fro; and when the length, obtained by reducing the thickness, has become inconveniently great, 
 the piece is cut into two, and each half milled in a similar manner. Thus the lead continues to pass 
 between the rollers to the number of seven or eight hundred times, having its thickness diminished and 
 its length increased by regular degrees. From 800 to 400 feet in length, with a width of seven or eight, 
 is the average quantity of roofing-lead produced by these means from one of the plates. The lead is 
 then coiled up in a roll, and in that form is sold to the plumber, who adapts it to his various purposes. 
 
 The manufacture of lead-pipe, like that of sheet-lead, combines the processes both of casting and 
 elongating, or drawing. Whatever be the required diameter and thickness of the pipe, it is first cast in 
 a short piece of great thickness, and then elongated, by which the thickness becomes reduced. The 
 diameter of the cast piece is, internally, the same as that of the required pipe, the external diameter 
 being that which undergoes reduction. The first process is, therefore, to cast the short pieces of pipe. 
 These moulds measure from two to four feet in height, and are fitted for casting pipe whose diameter 
 varies externally from two to six inches, and internally from half an inch to four inches. The mould 
 consists of two semi-cylindrical halves, which, on being brought together, form the external contour of 
 the pipe, while a spindle or steel core, running down the centre of the hollow cavity, regulates the in- 
 ternal diameter of the pipe. 
 
 A small melting-furnace is appropriated for the pipe-casting, the lead being carefully skimmed from 
 dross while melting ; and when the fusion is complete the melted metal is poured into the mould, the 
 upper end of which is open and the lower end closed. The quantity of lead required for each mould 
 varies from about 24 to 200 pounds, according to the thickness of the pipe. The metal being solidified 
 and sufficiently cool for handling, the two halves of the mould are drawn asunder and the lead removed, 
 the technical name of the “ plug” being applied to the short thick piece of pipe thus produced. 
 
 Next ensues the very singular method whereby the plug is elongated to the required dimensions. 
 The “ drawing-bench” is a frame about thirty feet long and three in height, having in the middle of its 
 length mechanism for producing the elongation. An endless chain is kept in constant motion round two 
 wheels or rollers, one near the end and the other near the middle of the draw-bench, insomuch that a 
 hook or a clasp connected with one of the links would be forcibly drawn along the bench. A mandril, 
 or steel rod, corresponding in size with the internal diameter of the pipe, is inserted into one of the short 
 pipes or plugs, and then so connected with the endless chain as to be drawn along the bench ; but in 
 its progress the pipe has to pass through a hole in a steel plate, or die, rather smaller than the diameter 
 of the lead itself, by which its external diameter becomes somewhat reduced and its length increased. 
 Again and again is the pipe, with its contained mandril, drawn along the frame, the die being exchanged 
 after each drawing and replaced by one of smaller diameter. In producing a two-inch pipe no fewer 
 than sixteen dies are employed, the diameters of which descend in a regular series. The hole through 
 the die is conical, that is, larger on one side of the die than on the other, and the lead enters the hole 
 at the widest part, whereby a process of compression is undergone ; but at a certain point in the opera- 
 tions a “cutting-die” is introduced, that is, one wherein the lead is at once exposed to a cutting edge, 
 the result of which is that a thin film is cut or scraped from tin? whole surface of the pipe. By the 
 time that all tliis routine is undergone the metal has become more dense and compact, the temperature 
 so high as scarcely to be bearable by the hand, the length greatly increased, and the external diameter 
 proportionably diminished. After this the elongated pipe is removed from the mandril, and is then 
 ready for disposal to the plumber. 
 
 Lead-pipe is also manufactured by forcing it through dies, and 
 the process, as improved by Mr. Corneil, of New York, is thus de- 
 scribed by him in the specifications of his patent : 
 
 My invention consists of certain improvements in the arrangement 
 and combination of the machinery or apparatus heretofore used for 
 similar purposes, and in the construction and application of certain 
 additional machinery or apparatus, and the combination thereof wi!h 
 the other apparatus, as herein described. 
 
 My machine is applicable to the manufacture of pipes and tubes o f 
 lead, and such other metals and their alloys as are capable of being 
 squeezed or forced by means of great pressure from a cylinder or re- 
 ceiver through or between apertures, dies, cores, or mandrils, when in 
 a solid or semi-fluid state, and is mainly referable in its general con- 
 struction and purposes to the machine patented by Thomas Burr in 
 Great Britain, and described in the first volume of the first series of 
 the “ London Journal of Arts and Sciences.” 
 
 In my machine I use the hydraulic press, the lead cylinder or re- 
 ceiver, the columns or pillars connecting the hydraulic press with the 
 lead cylinder, the movable ram for pressing the piston upon the lead 
 m the cylinder or receiver, the dies and cores to give the pipes the 
 required form, and calibre, and dimensions, and such other parts of 
 the old machines as may be necessary, substantially similar to the 
 machine of the said Thomas Burr. 
 
 Fig. 2580 represents my invention, showing how, by different ar- 
 rangements of the machinery, the power may be applied to the 
 lead cylinder, which in this case is movable, while the piston is sta- 
 tionary. 
 
 This figure is a sectional view of the hydraulic press and pipe ma- 
 chinery in which the long movable core is used. In the figure, A is the hydraulic cylinder, and B the 
 ram rising therefrom. A cross-head is attached to the hydraulic cylinder in the usual manner, and i» 
 
 2580. 
 
 
218 
 
 LENS. 
 
 connected with the upper cross-head I, by means of the rods L L, which are secured at the top and 
 bottom by the nuts M M M M, turned on the screws at the ends of the rods. On the top of the ram a 
 head-block C is placed, and there secured. A foot-block D is attached to the bottom of the lead cylin- 
 der E, and the head-block, the foot-block, and the lead cylinder are secured firmly together by the bolts 
 F F. By this arrangement the lead cylinder will be moved upwards and downwards by the ram of the 
 hydraulic press. To the upper cross-head I the hollow piston H is attached, and secured by means of 
 the bolts K K having screws and nuts at the ends. The die P is placed in the lower end of the piston, 
 which is hollowed throughout, and communicates with the aperture 0 made through the upper cross 
 head. The long movable core N which is used in this case, is firmly secured to the head-block of the 
 ram, extending upwards through the centre of the lead cylinder, and a short distance above it, to be 
 inserted through the die in the end of the piston. The position of the core is regulated by means of the 
 set-screws G G, four in number, which move the core laterally, and set it centrally in the die. When 
 all the parts are thus arranged, the lead cylinder is raised up to the lower end of the piston, the end of 
 the core passing through the die, and being there adjusted centrally by the set-screws, the lead cylinder 
 is charged, and the power of the press applied. 
 
 The ram is forced upwards, carrying the lead cylinder before it, which passes over the piston. The 
 pipe is formed at the point of pressure, as before, passing through the hollow piston through the aper- 
 ture O, and out at the top of the machine. The core in this arrangement moves upwards with the lead 
 cylinder through the die and the hollow piston. A strong metallic ring is placed and firmly secured on 
 the lower cross-head, encircling the ram B, to act as a guide for the ram, keeping it steady and giving 
 it the prec se direction. 
 
 LENS. In optics, a piece of glass, or other transparent substance, having its two surfaces so formed 
 that the ray s of light have their direction changed by passing through it ; so that they either converge, 
 tending to a point beyond the lens, or diverge, as if they proceeded from a point before the lens ; or 
 become parallel, after converging or diverging. 
 
 A double convex lens, Fig. 2581, is bounded by two convex spherical surfaces, whose centres are on 
 opposite sides of the lens. It is equally convex when the radii of both surfaces (that is, the distances 
 from the centres to the circumferences of the circle they belong to) are equal, and unequally convex 
 when their radii or distances are unequal. 
 
 A plano-convex lens, Fig. 2582, is bounded by a plane surface on one side, and by a convex one on 
 the other. 
 
 A double concave lens, Fig. 2583, is bounded by two concave spherical surfaces whose centres are on 
 opposite sides of the lens. 
 
 A plano-concave lens, Fig. 258-1, is bounded by a plane surface on one side, and a concave one on 
 the other. 
 
 A meniscus, Fig. 2585, is bounded by a concave and a convex spherical surface ; and these two sur- 
 faces meet, if continued. 
 
 The focal distance, or distance of the focus from the surface of the lens, depends both upon the form 
 of the lens and of the refractive power of the substance of which it is made ; in a glass lens, both sides 
 of which are equally convex, the focus is situated nearly at the centre of the sphere of which the surface 
 of the lens forms a portion ; it is at the distance, therefore, of the radius of the sphere. Fig. 2587. 
 
 Plano-convex lens and rays converging. — Fig. 2586. Lenses that have one side flat and the otner 
 convex, (plano-convex,) have their focus at the distance of the diameter of a sphere, of which the convex 
 surface of the lens forms a portion, as represented in the figure. 
 
 According to some opticians, the greatest diameter of a lens is half an inch ; if it exceed that thickness 
 they do not call it a lens, but a lenticular glass. Lenses are made either by blowing or grinding. 
 Blown lenses are small globules of glass melted in the flame of a lamp ; ground lenses are reduced by 
 grinding and polishing. A variety of simple apparatus is employed in the processes of grinding and 
 polishing lenses, among which the one shown in Fig. 2588 is much used, a shows the edge of a circular 
 lap or slab, used for grinding flat glasses upon ; b a circular tool or block, upon the under surface of 
 which the glasses to be ground are cemented; c is a reciprocating bar; d a box containing any weighty 
 matter ; e a long mortised aperture in the frame, through which the bar c freely works ; f a crank ; g a 
 winch; h a double pulley-wheel, the axis of which rests in the block j a single pulley-wheel. Now 
 on turning the crank bv the winch g, the bar c gives to b an eccentric motion ; the attrition of b on the 
 surface of the lap a being increased or diminished at pleasure by increasing or diminishing the load in 
 the box d. It should be noticed that the cord which passes round the pulley h is crossed previous to 
 its embracing the periphery of the pulley i, consequently a motion is given to the lap a tire reverse of 
 that given to b, which is considered to produce the best effect of grinding. The apparatus described is 
 
LEWIS. 
 
 2 IS 
 
 devoted to the producing of plane surfaces to optical glasses ; but the apparatus on the other side oi 
 the machine is, at the same time, by similar arrangements, employed in grinding concave or convex sur- 
 faces. For this purpose a variety of laps and other tools are so made as to fit on the bed l, which bed 
 is adjustable by four equidistant screws. The pulley o is driven by another band on the pulley h, anc 
 the required pressure given by another loaded boxy*. The several tools used are screwed on at m, and 
 are adapted for ready changing, that the operations may be performed with celerity. 
 
 LEV ER. One of the Mechanical Powers, which see. 
 
 LEWIS. When stone are to be laid into masonry, that are too heavy for the workmen to handle 
 
 2591. 
 
 w ithout resort to machinery, it becomes necessary to provide means for suspending them so as to leave 
 the lower surface and two of the joints unobstructed. This is usually done by drilling a hole in tha 
 upper surface, in which is placed an iron 
 bolt secured by a key. The bolt has an 
 eye or ring, by which it may be attached 
 to the machine which is to suspend the 
 stone. This bolt and key is called a 
 “ Lewis,” from the name of the inventor. 
 
 The single lewis is in the form of Fig. 
 
 2689, and is generally used to suspend 
 stone not exceeding 600 pounds weight. 
 
 The double, or chain lewis, is in the fomn 
 of Fig. 2590. This was the form of the 
 lewis which was chiefly used on the U. S. 
 
 Dry Dock at Brooklyn, for suspending stone 
 from 600 pounds to 10,000 pounds; and 
 stone of twice this weight were suspended 
 with two lewises of this description. 
 
 The floor of this dock is an inverted arch, 
 and the sides are made up of alter courses, 
 the top surface of which show as coping 
 stone. To suspend stone of this descrip- 
 tion, as well as steps and coping, without 
 marring the upiper surface, has been long a 
 desideratum. 
 
 In Fig. 2591 is exhibited a drawing of 
 Lidgewood’s lever lewis, by means of which 
 all this description of stone were set on 
 the dock — some of them weighing seven 
 tons. 
 
 The mitre sills on the same work were 
 enormously heavy : the centre stone weighed 
 nearly twenty-five tons, and two others over 
 twenty tons, and several others nearly as 
 large. These stone were suspended by a 
 frame, as shown in Fig. 2691. 
 
 
 LIGHT. The cause of those sensations which we refer to the eyes, or that which produces the 
 sense of seeing. The phenomena of light and vision have always been regarded as one of the most 
 interesting branches of natural science ; though it is only since the days of Newton that they have been 
 examined with such care as to afford grounds for any safe speculation respecting the nature of light, and 
 the mode of its propagation through sprace. 
 
 Experiments of the simplest and most familiar kind suffice to show that light is propagated from 
 
220 
 
 LIGHT. 
 
 luminous bodies in all directions. Provided nothing intervenes to intercept the light, they arc seen it 
 all situations of the eye. 
 
 Another property of light is, that it requires time for its propagation. The velocity with which it 
 passes from one point to another is, however, so great, that, with respect to any terrestrial distances, the 
 passage may be considered as instantaneous. But astronomy furnishes the means, not only of detecting 
 its propagation, but of measuring its velocity with great precision. The eclipses and emersions ot 
 Jupiter’s satellites become visible about 16 min. 26 sec. earlier when the earth is at its least distance 
 from Jupiter, than w T hen it is at its greatest. Light, therefore, occupies above a quarter of an hour in 
 passing through the diameter of the earth's orbit. Now the sun’s distance from the earth being nearly 
 95,000,000 of miles, it follows that light must travel through space with the prodigious, though finite, 
 velocity of 192,500, or nearly 200,000 miles in a second of time, and consequently would pass round the 
 earth in the eighth part of a second. Astounding as this conclusion is, no result of science rests on more 
 certain evidence. It is also proved, by the phenomena of aberration, that the light of the sun, planets, 
 and all the fixed stars, travels with one and the same velocity. 
 
 Theories of light. — Two different theories have long divided the opinion of philosophers respecting the 
 nature and propagation of light. One of these consists in supposing it to be composed of particles of 
 excessive minuteness, projected from the luminous body with a velocity equal to nearly 200,000 miles in 
 a second. This hypothesis was adopted by Newton, and, till recently, has been acquiesced in by the 
 greater number of writers on optics. The other hypothesis supposes light to be produced by the vibra 
 tions or undulations of an ethereal fluid of great elasticity, which pervades all space and penetrates all 
 substances, and to which the luminous body gives an impulse which is propagated with inconceivable 
 rapidity, in spherical superficies, by a sort of tremor or undulation, as sound is conveyed through the 
 atmosphere, or a wave along the surface of water. Both of these hypotheses are rendered probable by 
 the great number of phenomena of which they afford a mechanical explanation ; but they are both, also, 
 attended with very great difficulties. Other theories have also been proposed; but they have not met 
 with such general attention from philosophers as to make it necessary to explain them in this place. 
 
 Corpuscular theory of light. — Sir John Herschel, in his admirable Essay on Light, in the Encyclopaedia 
 Metropolitana, states the principles of the Newtonian or Corpuscular theory as follows : 
 
 1. “That light consists of particles of matter possessed of inertia, and endowed with attractive and 
 repulsive forces, and projected or emitted from all luminous bodies with nearly the same velocity, about 
 200,000 miles per second. 
 
 2. That these particles differ from each other by the intensity of the attractive and repulsive forces 
 which reside in them ; and in their relations to tire material world ; and also in their actual masses, or 
 inertia. 
 
 3. That these particles, impinging on the retina, stimulate and excite vision : the particles whose 
 inertia is greatest, producing the sensation of red ; those of the least inertia, of violet ; and those in which 
 it is intermediate, the intermediate colors. 
 
 4. That the molecules of material bodies and those of light exert a mutual action on each other, 
 which consists in attraction ana repulsion, according to some law or function of the distance between 
 them ; that this law is such as to admit, perhaps, of several alternations or changes from repulsive to 
 attractive force ; but that when the distance is below a certain very small limit it is always attractive 
 up to actual contact ; and that beyond this limit resides at least one sphere of repulsion. This repulsive 
 force is that which causes the reflection of light at the external*surfaces of dense media ; and the interior 
 attraction that wdiich produces the refraction and interior reflection of light. 
 
 5. That these forces have different absolute values or intensities, not only for all different material 
 bodies, but for every different species of the luminous molecules, being of a nature analogous tc 
 chemical affinities or electric attractions ; and that hence arises the different refrangibilities of the rays 
 of light. 
 
 6. That the motion of a particle of light, under the influence of these forces and its own velocity, is 
 regulated by the same mechanical laws which govern the motions of ordinary matter; and that there- 
 fore each particle describes a trajectory, capable of strict calculation as soon as the forces which act on 
 it are assigned. 
 
 7. That the distance between the molecules of material bodies is exceedingly small in comparison 
 with the extent of their spheres of attraction and repulsion on the particles of light. 
 
 8. That the forces which produce the reflection and refraction of light are, nevertheless, absolutely 
 insensible at all measurable or appreciable distances from the molecules which exert them. 
 
 9. That every luminous molecule, during tire whole of its progress through space, is continually 
 passing through certain periodically recurring states, called by Newton fits of easy reflection and easy 
 transmission, in virtue of which they are more disposed, wdien in the former states or phases of their 
 periods, to obey the influence of the repulsive or reflective forces of the molecules of a medium; and 
 when in the latter, of the attractive.” 
 
 Such are the postulates on which the corpuscular theory of light depends. Most of them may be 
 admitted without difficulty; and they afford data for the application of mathematical reasoning to the 
 phenomena, which may be investigated by the same sort of analysis with which mathematicians are 
 already familiar in the theories of heat, capillary attraction, and other molecular forces. 
 
 Undulatory theory. — The principles of the undulatory theory are thus stated by Sir J. Herschel: 
 
 1. “ That an excessively rare, subtle, and elastic medium, or ether, fills all space, and pervades all 
 material bodies, occupying the intervals between their molecules ; and either by passing freely among 
 them, or by its extreme rarity, offering no resistance to the motion of the earth, the planets, or comets, 
 in their orbits, appreciable by the most delicate astronomical observations ; and having inertia, but not 
 gravity. 
 
 2. That the molecules of the ether are susceptible of being set in motion by the agitation of the par- 
 ticles of ponderablo matter; and that when any one is thus set in motion it communicates a similai 
 
LIGHT, ARTIFICIAL. 
 
 22 1 
 
 motion to those adjacent to it ; and thus the motion is propagated further and further in all directions, 
 according to the same mechanical laws which regulate the propagation of undulations in other elastic 
 media, as air, water, or solids, according to their respective constitutions. 
 
 3. That in the interior of refracting media the ether exists in a state of less elasticity, compared with 
 its density, than in vacuo, ( i . e., in space empty of all other matter ;) and that the more refractive the 
 medium, the less, relatively speaking, is the elasticity of the ether in its interior. 
 
 4. That vibrations communicated to the ether in free space are propagated through refractive 
 media by means of the ether in their interior, but with a velocity corresponding to its inferior degree of 
 elasticity. 
 
 5. That when regular vibratory motions of a proper kind are propagated through the ether, and, 
 passing through our eyes, reach and agitate the nerves of our retina, they produce in us the sensation 
 of light, in a manner bearing a more or less close analogy to that in which the vibrations of the air affect 
 our auditory nerves with that of sound. 
 
 6. That as, in the doctrine of sound, the frequency of the aerial pulses, or tire number of excursions 
 to and fro from the point of rest made by each molecule of the air, determines the pitch or note ; so, in 
 the theory of light, the frequency of the pulses, or number of impulses made on our nerves in a given 
 time by the ethereal molecules next in contact with them, determines the color of the light ; and that 
 as the absolute extent of the motion to and fro of the particles of air determines the loudness of the 
 sound, so the amplitude or extent of the excursions of the ethereal molecules from their points of rest 
 determines the brightness or intensity of the light.” 
 
 Whichever theory we adopt to explain the phenomena of light, we are led to conclusions which strike 
 the mind with astonishment. According to the corpuscular theory, the molecules of light are supposed 
 to be endowed with attractive and repulsive forces, to have poles, to balance themselves about their 
 centres of gravity, and to possess other physical properties which we can only ascribe to ponderable 
 matter. In speaking of these properties it is difficult to divest one’s self of the idea of sensible magni- 
 tude, or by any strain of the imagination to conceive that particles to which they belong can be so 
 amazingly small as those of light demonstrably are. If a molecule of light weighed a single grain, its 
 momentum (by reason of the enormous velocity with which it moves) would be such that its effect would 
 be equal to that of a cannon-ball of 150 pounds, projected with a velocity of 1000 feet per second. How 
 inconceivably small must they, therefore, be, when millions of molecules, collected by lenses or mirrors, 
 have never been found to produce the slightest effect on the most delicate apparatus contrived expressly 
 for the purpose of rendering their materiality sensible ! 
 
 If the corpuscular theory astonishes us by the extreme minuteness and prodigious velocity of the 
 luminous molecules, the numerical results deduced from the undulatory theory are not less overwhelm- 
 ing. The extreme smallness of the amplitude of the vibrations, and the almost inconceivable, but still 
 measurable rapidity with which they succeed each other, were computed by Dr. Young, and are ex- 
 hibited by Sir J. Iierschel in the following table : 
 
 1 
 
 Colors. 
 
 Length of undu- 
 lation in parts of 
 an inch. 
 
 Number of 
 undulations 
 in an inch. 
 
 Number of undulations 
 per second. 
 
 Extreme Red 
 
 0-0000266 
 
 37640 
 
 458,000000,000000 
 
 Red 
 
 00000256 
 
 39180 
 
 477,000000,000000 
 
 Orange 
 
 0-0000240 
 
 41610 
 
 506,000000,000000 
 
 Yellow 
 
 0-0000227 
 
 44000 
 
 535,000000,000000 
 
 Green 
 
 0-0000211 
 
 47460 
 
 577,000000,000000 
 
 Blue 
 
 0-0000196 
 
 51110 
 
 622,000000,000000 
 
 Indigo 
 
 0-0000185 
 
 54070 
 
 658,000000,000000 
 
 Violet 
 
 0 0000174 
 
 57490 
 
 699,000000,000000 
 
 Extreme Violet 
 
 00000167 
 
 59750 
 
 727,000000,000000 
 
 The velocity of light being 
 assumed at 192,000 miles 
 per second. 
 
 On a cursory view, it must appear singular that two hypotheses, founded on assumptions so essentially 
 different, should concur in affording the means of explaining so great a number of facts with equal pre- 
 cision and almost equal facility. This, however, is the case with respect to the corpuscular and undu- 
 latory theories of light, from both of which the mathematical laws to which the phenomena are subject 
 may be deduced, though not in all cases with the same degree of facility. 
 
 LIGHT, ARTIFICIAL. The importance of obtaining a brilliant and economical light for public and 
 domestic purposes, has exercised the ingenuity and scientific research of eminent men for a century past. 
 And although their labors have resulted in discoveries of great value, the desideratum so steadily 
 sought after has not yet been attained. 
 
 The introduction of coal-gas, in 1798, by Mr. William Murdock, engineer to Messrs. Bolton and Watt, 
 was an invention of the highest order, and one that has conferred most important benefits upon society. 
 The subsequent use of oil and resin, as substitutes for coal, to avoid the difficulties of purification re- 
 quired by the latter, did not result in any improvement of economy or illuminating power. The dis- 
 covery of the voltaic and oxy-hydrogen lime light was a brilliant addition to our stock of chemical 
 science, but neither of them have yet been reduced to any thing like a practical form suited to public or 
 domestic uses. 
 
222 
 
 LIME. 
 
 The requirements of the case may be stated thus: 1st, intense illuminating power; 2d, economy 
 3d, portability ; 4th, small radiation of heat ; 5th, perfect ventilation ; 6th, simplicity in the production 
 and steadiness of combustion, so as to insure uniform power of light. 
 
 To obtain an artificial light combining all these requisites, is now one of the most interesting problems 
 of this era of useful inventions, and its solution will place the discoverer on the same eminence with 
 Newton, Watt, Fulton, and Morse. There is, therefore, no field of research that promises more sub- 
 stantial rewards to the successful than the invention of a simple, economical, and powerful light, as the 
 want of it is felt by the whole civilized world. 
 
 That this subject has already attracted the attention of both scientific and practical men in this 
 country, as well as abroad, we have abundant proofs in the frequent announcement of grand discoveries 
 in the production of artificial light, that, upon investigation, prove to be either new discoveries of old 
 chemical experiments, by some tyro or quack, or else are of no value practically, owing to the chemical 
 or mechanical cost of production. 
 
 It is very easy to assure the public that water can be made to burn, or that a whole city is about to 
 be completely illuminated with a single gas-light. The demonstration of such wonders is, however, 
 probably reserved for a future age. At present we would only direct the attention of our ingenious 
 countrymen to the simple fact, that this subject is one of universal public importance, presenting a broad 
 scope for the exercise of their inventive faculties. 
 
 LIGHT-HOUSES. See Sea-Lights, under which head the subject should be treated. 
 
 LIGHTNING CONDUCTORS are pointed metallic rods, fixed to the upper parts of buildings to 
 secure them from strokes of lightning. They were invented and proposed by Dr. Franklin for this 
 purpose, and they exhibit a very important and useful application of modern discoveries in the science 
 of electricity. See Electricity. 
 
 LIFE-BOAT. A boat originally made at Shields, in 1*789, by Mr. Greathead, for saving the crews oi 
 shipwrecked vessels. The following are the general principles : The boat is wide and shallow ; the 
 head and stern are alike, for pulling in either direction, and raised, to meet the waves ; it pulls double- 
 banked, the oars being fir, for lightness, and fitted with thole-pins and grummets, and is steered with an 
 oar. The boat is cased round inside, on the upper part, with cork, in order to secure her buoyancy with 
 as many persons as she can carry, even though full of water ; the cork likewise assists in maintaining, or, 
 if overset, in recovering, the position of stable equilibrium. The boat is painted white, to be conspicuous 
 in emerging from the hollow of the sea. It is a curious fact that the smugglers paint their boats white 
 for the contrary reason, because dark-colored objects alone are discernible in dark nights. 
 
 The loss by fire constantly occurring on the western waters is a proof of the necessity for greater 
 and more effective means of saving life, than are yet adopted in our mercantile marine of all classes 
 nearly. That this should be so is doubly surprising, when, in our very midst, we have the remedy 
 in Francis’s galvanized iron life-boat, of which it may be stated, they are never leaky. They may 
 be thrown overboard without injury, or lessening their usefulness; they right themselves, if swamped ; 
 and, when full of water, a thirty-foot boat will sustain forty people, so long as they can hold on to 
 the beckets, with which each boat is provided. The non-inflammable material of their construction is 
 another great safety on going alongside a burning wreck ; and in a heavy sea their elasticity and buoy- 
 ancy preserves them alongside a sinking wreck, in circumstances which invariably destroy a wood-boat 
 at the time when she is most needed. These boats are manufactured by Mr. Francis, at the Novelty 
 Works of Stillman, Allen & Co., on the East River. 
 
 LIME. Carbonate of lime is the substance forming the principal ingredient of all natural limestones, 
 which may be classified, from their outward mineralogical characters, under the following arrangement: 
 
 Granular limestone, with a decidedly crystalline grain : the different varieties of marble, (Parian, 
 Carrara,) and particularly the old mountain limestone, belong to this class. 
 
 Compact limestone occurs in quite as great a variety of colored species as the foregoing, but is never 
 so white. It is found in all geological formations, and is named according to its age, or from the forma- 
 tions of which it is a member ; w 7 e thus have transition limestone, graywacke limestone, carboniferous 
 limestone, mountain limestone, shell limestone, lias limestone, fresh-water limestone, &c. 
 
 Limestone Breccia, consisting of lumps of limestone, cemented together by another limestone 
 mass. 
 
 Limestone marl, more or less uniformly mixed with clay, of a dense earthy fracture. This and the 
 foregoing variety belong to no particular member of the stratified rocks, exclusively. 
 
 Silicious limestone contains numerous silicious minerals, as quartz, hornestene, chalcedony, opal, <Lc. 
 This variety is dense, and interspersed often with cavities ; it is gray, or yellowish-white. 
 
 Fetid limestone is characterized by the bitumen which it contains, and which is rendered perceptible 
 to the smell by friction. It is generally dense, and exhibits stratification. It is called friable marl 
 when it occurs as a disconnected earthy mass, and is of a dark color. 
 
 Chalk is a dense, earthy rock, imparting color when rubbed, seldom other than of a white color. It 
 is distinguished as being the matrix of flints. 
 
 Coarse lime is dense, earthy, approaching sandstone in appearance, and contains a large proportion ol 
 quartz-sand and clay, and is stratified. 
 
 Calcareous tufa consists of layers of lime which are pretty free from foreign matters, and is still in 
 the process of formation. Generally unstratified. In some parts it is loose, porous, and earthy ; in 
 others dense, passing into a variety of dense limestone. 
 
 Calcareous tufa and Travertin belong to this class. Lime of similar origin is called calcareous sinter 
 when the stratification contains crystalline particles (calcareous spar or arragonite) arranged like laj ers 
 of bark, one above the other, often in the form of columns. 
 
 [These formations are produced by the solvent action of water containing carbonic acid upon car- 
 bonate of lime. 
 
 The stalactites and stalagmites which frequently cover the roofs and floors of certain caverns, are also 
 
due to the same cause. The water which permeates the rocks above them dissolves the carbonate of 
 lime, by reason of the carbonic acid which it contains. In dropping from the roof, however, it remains 
 suspended for some time, and, losing a certain part of the acid, deposits also a portion of the carbonate 
 of lime, previously held in solution. The accumulation of these minute portions of lime gradually form 
 the stalactites. The same takes place on the floors of the caverns, giving rise to the formation of the 
 stalagmites.] 
 
 / Dolomite is characterized by a large amount of magnesia ; it is generally granular, and seldom earthy 
 or massive. It is not distinctly stratified, but sometimes bituminous. 
 
 The characters of limestone which stand in connection with the theory of the earth’s formation, the 
 geological characters, therefore, lead to a totally different classification. The examination of a limestone 
 in one point of view only, must therefore lead to a very imperfect knowledge of its nature. The mere 
 study of its chemical constitution, would also afford but a very partial means of judging it. 
 
 Many limestones exhibit clear indications of having been put in motion in the liquid state. Limestone 
 of this kind must possess a high degree of purity, as, if this were not the case, (and clay or other sub- 
 stances were present,) the result of the fusion would certainly have been different, and would not have 
 ended in the formation of crystals of pure carbonate of lime. 
 
 Other limestones, which have been formed by precipitation from soluble salts of lime, are more likely 
 to contain foreign admixtures, which have been deposited by chemical or mechanical agency. Thus, 
 some contain magnesia, iron, and manganese uniformly disseminated through them ; others are mixed 
 in the same manner with aluminous or silicious particles, or these are interstratified with them. 
 
 Others, again, and a whole series of limestones, have obviously been formed with the concurrence of 
 the animal creation, and it is of importance to ascertain what part the living beings have performed in 
 this general development. Thus, at the present moment, whole islands are being raised up in certain 
 latitudes and oceans, from the calcareous coverings of the coralline animals, just as in former ages the 
 range of the Jura and other mountains have been produced from the same agency. There are likewise 
 limestones, as the shell limestones, which are composed of masses of shells of crustaceous animals. The 
 shells of these animals have been filled with lime, and cemented together so as to form a more or less 
 solid rock. The bodies of the animals have not, however, disappeared without leaving a trace behind 
 them ; for that which is denominated bituminous in these rocks, is generally the residue of decomposed 
 animal matter permeating the entire mass of the stone. 
 
 While many limestone formations have been deposited from sea-water, others appear to have been 
 decidedly formed in fresh water. Calcareous tufa is still being deposited in numerous places from 
 springs, the carbonic acid in which, under greater pressure, dissolves lime, which is again precipitated, 
 when the carbonic acid is evolved under the lesser pressure of the atmosphere. 
 
 Pure burnt lime absorbs water with great avidity, and occasions a great disengagement of heat, 
 forming a dense, very soft paste, or, as it is called, becoming fat; the limestones containing magnesia 
 are poorer in proportion as they approach to the composition of dolomite. The oxides of manganese 
 and iron which are so frequently found in the limestones, have probably been formed by the action of 
 the atmosphere upon the protoxides of these metals. 
 
 Besides the carbonates, the silica and alumina contained in the limestone rocks are also of interest. 
 They exist in the most variable proportions, often combined in the form of clay, sometimes associated 
 with magnesia, sometimes alone. The silica is often, but the alumina never in excess, so that both re- 
 main undissolved in- acids. Their presence is without any perceptible influence when they are present 
 in small quantity ; but when their amount exceeds 10 per cent., the limestones are slaked very 
 slowly and with difficulty after burning, their affinity for water is diminished, and they are then appli- 
 cable to very different purposes. Of these we shall have occasion to speak under the head of hydraulic 
 lime. 
 
 Lime burning — Chemical process. — Carbonate of lime is not decomposed at a low red-heat, but is 
 converted at a bright red-heat into carbonic acid and lime. The temperature at which the decompo- 
 sition is effected is, however, influenced by circumstances, or rather depends entirely upon the facility 
 afforded the carbonic acid for escape when it has been expelled from the lime. If the limestones are 
 constantly surrounded with an atmosphere of carbonic acid, the further evolution of carbonic acid from 
 them is, according to Faraday, very much impeded ; but if the gaseous acid is removed as quickly as it 
 is expelled from the lime, the process of removing the future portions of acid is much accelerated. In 
 close vessels, the decomposition is stopped as soon as the space not occupied by the lime has become 
 filled with carbonic acid. 
 
 It will be proper to explain the processes employed in burning lime, which must be viewed as a 
 preparation of the limestone for its numerous applications in the arts. The burning of lime is accom- 
 plished in three modes : 1. Without a kiln ; 2. By an intermittent kiln ; and 3. By a kiln in constant 
 operation, or, as it is called, a perpetual kiln. 
 
 1. Without a kiln. — In Wales and Belgium lime is burnt precisely as we burn charcoal; the pile of 
 limestone and fuel mixed is covered with turf, making a heap of about 16 feet in diameter at the base, 
 and 12 feet at the summit, which occupies in burning from six to seven days. 
 
 Intermittent kiln. — One of the simplest, but at the same time crudest arrangements, is the following : 
 The kiln is perpendicular, and constructed of the same limestone (in the dry state and without mortar) 
 as that which it is intended to burn. It is placed at the side of a steep hill or declivity, so that the 
 mouth is equally accessible for charging the kiln, as the fire-place for introducing the fuel. The shaft 
 is round throughout, six feet in diameter at the top, and gradually expands to ten feet at about one-third 
 from the bottom. A sudden contraction of the diameter is there introduced, forming a sort of projection 
 inwards of one foot in width, and the size of the kiln then diminishes until it acquires a diameter of 
 about 6]- feet at the bottom. A projection or ledge is carried in the form of a ring all round the interior 
 of the furnace, but not at the same height from the ground, inclining towards the stoking-liole. The 
 charging is carried on upon a certain fixed plan. The lime-burner begins by constructing a pointed 
 
224 
 
 LIME. 
 
 arch upon the ledge, with the large pieces of limestone which are selected expressly for this purpose. 
 He forms in this manner a kind of support or foundation, upon which the other limestones are thrown 
 in, at random, from above, the largest first and the smaller pieces afterwards, which are also piled up 
 above the mouth of the kiln. "When the charge has been thus arranged, a pile of wood is erected in the 
 space below the arch, and ignited. The regulation of the fire is by no means an unimportant point, as 
 the possibility of completing the burning depends upon the length of time that the arch, which acts as 
 a support, will endure. The stones composing this arch being unconnected by any cement and unhewn, 
 and only touching in a few places so as to leave a free ingress for the flames, a slight shock will often 
 cause the downfall of the whole, and put a stop to the operation. The sudden and powerful action of 
 the fire, by expanding the stones very rapidly, and driving out the moisture with such force as to rup- 
 ture the stones, will often produce a sufficient shock to create a catastrophe of this kind. The art of 
 burning lime, therefore, consists in bringing the mass of limestone as gradually as possible to a red-heat. 
 The first period is called the smoking , because the gases evolved from the fuel, being too much cooled, 
 are imperfectly burnt, and pass off in the form of a thick smoke. The temperature generally increases 
 in a kiln of this kind during the first two-thirds of the time, until it attains a white-heat, and diminishes 
 again in the last third. The firing must, however, be kept up until the uppermost stones have been 
 completely burnt. During the firing the bulk of the stones is much diminished, aud the heap above the 
 mouth of the furnace sinks gradually down. 
 
 The evils of such a system of burning, which involves an enormous waste of fuel, (the loss of time not 
 being taken into consideration,) are obvious. The furnace must be allowed to cool each time it is dis- 
 charged, and the entire amount of heat, or, what is the same thing, the whole of the wood employed for 
 raising die very extensive sides of the kiln to the temperature at which lime is burnt, must be sacrificed. 
 It is also evident that, in such a system of burning, the lower half of the limestone must be thoroughly 
 caustic, while the upper portions are still in the mild state. The upper part is at a very considerable 
 distance from the fire, and removed from the direct action of the flames, is burnt, consequently, at a 
 much greater cost of fuel than would otherwise be necessary. At the same time the lower layers in 
 the kiln are exposed to the constant danger of becoming over-burnt, which very much injures the quality 
 of the lime. 
 
 A great advantage is gained by constructing the kilns of brick-work, in a more solid manner, giving 
 the shaft more appropriate dimensions and shape, and building the kilns in situations less subject to be 
 obstructed in working by moisture, &c. 
 
 These improvements have been carried out in the kiln shown in Fig. 2592. Instead of a rudely 
 constructed wall, an outer wall is erected in these furnaces, with an internal one of solid brick-work. 
 The fire is placed upon the grate which separates the ash-pit a from the fireplace b. The grate is really 
 a permeated brick arch. 
 
 The perpetual or draw kilns are constructed as follows: Fig. 2593 represents a vertical section of a 
 common form of perpetual kiln constructed for a coal-fire ; Fig. 2594 is a horizontal section of the same 
 through the drawing-holes. The actual burning-space is a shaft in the form of an inverted cone, wide at 
 the top and narrow at the bottom. There is no separate hearth, the apertures a a a, of which there are 
 three, serving only for drawing out the lime. A layer of brushwood is first placed at the bottom of the 
 kiln, upon this some coal, then a layer of limestone, which is again covered with coal, and then another 
 layer of limestone, and so on until the kiln is filled. The last layer of stone is heaped up above the 
 mouth of the kiln, and the progress of the firing is judged of by the manner in which it sinks down ; 
 the sinking in this case being due, not only to the diminution in bulk of the stones, but also to the con- 
 sumption of the fuel As soon as the uppermost layer has sunk down to the level of the top of the 
 kiln, another charge of coal and limestone is thrown upon it. In the mean time, at intervals of one-half 
 to one-quarter of an hour, the lime which has sunk to the bottom of the kiln is drawn out through the 
 holes. The lower the charges sink in the kiln the more the coal is consumed, and the less space they 
 will occupy ; for this reason the inverted conical form of the kiln is the most appropriate. The intensity 
 of the fire can be regulated with perfect ease by adding more or less coal with each charge of limestone. 
 The draught may be impeded by stopping the apertures entirely or in part. In a kiln of the above 
 
LIME. 
 
 225 
 
 2596 . 
 
 dimensions, 500 cubic feet of lime are drawn in twenty-four hours, and the consumption of coal is about 
 two tons. 
 
 Fig. 2595 represents a section, and Fig. 2596 a plan of one of the most approved forms of perpetual 
 kilns in use in Prussia, in which one part of wood and four parts of peat are 
 used, ddcldd are openings at bottom for drawing the lime as it is burnt; 
 c c c c c fire-furnace for the fuel, whose mode of connection with the cavity 
 where the limestone is placed may be seen at c in the vertical section, which 
 also shows at d the manner in which the lime may be drawn. At a a is shown 
 a lining of fire-brick, back of which is a cavity b b filled with cinders, which 
 act as a non-conductor of heat. 
 
 The outside is built of rough stone. It produces about 250 bushels of lime 
 daily. 
 
 Scale, 12 feet to 4 inch. 
 
 Coal is a kind of fuel that is easily broken in small pieces, in a convenient 
 state for spreading about between the layers of limestone. Another advan- 
 tage arising from the use of coal is the small quantity of ash which it leaves, 
 and which is easily removed from the kiln with the burnt lime. These remarks do not apply to wood 
 which is reduced with difficulty into small pieces, and not being equally distributed amongst the lime 
 stone, impedes the regular burning and delivery of the lime ; nor to peat, which in general leaves so 
 large a proportion of ash as to subject the kiln to the danger of becoming Stopped. In those cases 
 where a perpetual process must be combined with the use of wood and peat as fuel, the construction oi 
 the kiln must undergo a suitable modification. While the kiln retains its character as a perpendicular 
 or shaft furnace, the fuel, instead of being interstratified with the limestone, is burnt on separate hearths 
 at the sides of the shaft, and the flame is conducted into the latter, which, in this case, contains nothing 
 but the material to be burnt. The number of the fires, which must always be symmetrically arranged 
 round the circumference of the shaft, is regulated by the size of the kiln, so that kilns with three, four, 
 and five fires are met with. The fuel consumed in furnaces of this construction must, of course, yield a 
 long and lively flame, as from wood, peat, or coal ; but for the latter, the arrangement is not so econom- 
 ical as the plan of stratification previously described. 
 
 Fig. 2591 is a vertical section of a plain perpetual kiln, built in Berkshire, Mass. It is 25 feet high, and 
 built of alternate layers of fire-brick and stone. It is four-sided ; consisting of a single chimney 4 feet 
 square on the inside, and 8 feet on the outside, making the walls 2 feet thick. 
 
 To the height of 7 feet from the bottom it is 12 feet in one direction, for the 
 purpose of making room for the furnaces d d, in which wood only is burnt, and 
 which are 2 feet high and 20 inches wide. For the passage of the heat into 
 the limestone in the chimney the bricks are laid up like a grate ; a a are ash- 
 pits beneath the fires, b an opening for clearing the lime from the bottom of 
 the chimney — being about 18 inches square. The kiln consumes from 2 to 24 
 cords of wood daily, and produces 75 bushels of lime, which is drawn out at 
 intervals of 8 hours. Scale, 12 feet to a half inch. 
 
 Consumption of fuel. — Notwithstanding the great saving of fuel, which is 
 effected in perpetual kilns, yet it must be borne in mind, that these kilns de- 
 mand the entire attention of the workman, and cannot be well attended to as 
 a casual occupation, or as a secondary branch of husbandry, for instance ; 
 it must also be remembered that perpetual furnaces are always yielding, that 
 is, they produce, in the same time, a much larger amount of burnt lime, and 
 are, consequently, only economical where there is a large and constant demand 
 for the produce. Every improvement in the construction of lime-kilns would 
 be a great boon to the public, for they must be decidedly classed amongst the 
 chief sources of the waste of fuel. The best mode of arriving at some sure 
 foundation from which to calculate the amount of this waste, will no doubt 
 be, by ascertaining the theoretical amount of fuel that is necessary to burn 
 a given weight of lime, and making this result the standard by which to compare the real loss. 
 It may be stated that 1 lb. of wood fuel is capable of heating 26 lbs. of water 100° C. If the specific 
 heat of limestone and carbonic acid is taken at J that of water, and the temperature at which lime is 
 rendered caustic is calculated at 800° C., it results, first, that 1 lb. of wood will heat 8 X 26 —78 lbs. 
 of lime to 100°, and consequently =9'75 lbs. of limestone to 800° ; or in other words and round 
 numbers, only -A. of the weight of the lime is requisite. In practice from 4 to 6 times as much is con- 
 sumed. The limestone, it is true, does not lose its carbonic acid all at once, as the calculation presup- 
 poses, even when it has acquired the proper heat, but the acid is evolved very gradually ; it is, conse- 
 quently, not only necessary to heat the kiln for a single instant to the proper temperature, but to keep 
 up that temperature for a considerable time. But, even if the quantity of wood calculated as necessary 
 be doubled, on account of this latter .circumstance, yet there still remains a loss of an equal quantity, 
 and it may be positively asserted, that the quantity of wood consumed in the lime-kilns is about as 
 much again as it should be. The heating power of coal being to that of wood as 60 : 26, for every 
 10 lbs. of lime burnt there should be 0'43 lbs. of coal consumed. But, as was stated above, for every 
 cubic foot of lime, from | to -J cubic foot of coal is burnt, which is equivalent to from 2 4 to 3 lbs. of 
 coal for 10 lbs. of lime, and consequently a very much greater waste. 
 
 Lime may be burnt, like bricks, in mounds ; but the irregular form of the pieces, and the contraction 
 which ensues, renders the process difficult, and it is consequently seldom practised. 
 
 Produce. — Chemically, pure carbonate of lime loses 44 per cent, of carbonic acid, and yields, after 
 burning, 56 per cent, of caustic lime. The produce from the kilns upon a large scale is much less when 
 the limestone is very moist, and greater when it contains a large proportion of clay, which loses nothing 
 Vol. II. — 15 
 
226 
 
 LIME. 
 
 ill the kiln. The average amount of produce obtained, ranges between 45 and 77 per cent., the ordinary 
 quantity being about 54 per cent. The contraction is not so considerable as might be expected, as th« 
 burnt lime is very porous. The specific gravity of limestone is diminished from J to ^ by binning, and 
 its volume is reduced from 10 to 20 per cent. Triest found, by direct experiment, the weight of a solid 
 cubic foot (Hessian) of Riidersdorf limestone = 93 lbs., after burning — 48 lbs. ; the loss was, therefore, 
 
 45 lbs. or 48 per cent. 100 lbs. of fresh Rodheim limestone, to give another example, occupy a 
 space =299, after burning, (when they ought to weigh 60 lbs.) the space which they occupy is reduced 
 to 183 ; the contraction, therefore, amounts to 12^ per cent. 
 
 Resides the lumps or shells of lime, there is always a portion leaves the kiln in the state of powder, 
 which is in consequence of the stones splitting in the fire, or is due to the friction in charging and dis- 
 charging the kiln. 
 
 Action of aqueous vapor in the kiln. — Moist limestone is said by old lime-burners to burn much 
 more easily than dry limestone. This fact, which is so w r ell established among them that they prefer 
 burning stones fresh from the pit, or even moisten those which have become dry in the air with water 
 before putting them into the kiln, is not without a true foundation, although it is often misunderstood in 
 practice. 
 
 When, on the one hand, it cannot be denied that limestone is more easily burnt under the influence 
 of a current of steam, yet on the other, it is very questionable whether the practice of burning moist 
 stones is really advantageous. The practice of bringing moist stones into the kiln is equivalent to the 
 exposure of limestone very much below a red-heat to the action of a current of vapor, as far the greater 
 part of the water must be uselessly expelled (with a proportionate waste of fuel) before the stones 
 acquire a red-heat. 
 
 Burnt lime. — Lime, when burnt, combines with the free silica at a red-heat, or enters as a constituent 
 into the compound silicate of lime and alumina which is formed. It will be obvious from these facts, 
 that the foreign substances must exercise considerable influence upon the quality of the burnt lime. 
 In the purer varieties of limestone that contain but very little foreign matter, the influence is imper- 
 ceptible. As the clay and silica are less prominent in these instances, the action of the magnesia is 
 rendered still more obvious, and when present to the amount of 10 per cent., affects the heating of the 
 lime, and diminishes its property of slaking and forming a soft impalpable paste ; in short, renders it 
 poor. When the amount of magnesia exceede J, the poorness of the lime is so great as to render it 
 useless. The nature of the limestones is not solely dependent upon the foreign substances which they 
 contain, but also upon the mode of regulating the furnace ; while one portion of the shells exhibits the 
 proper amount of heat when slaked, other pieces will slake very slowly, and the water will often hardly 
 act at all upon them ; they are then said to be dead-burnt. 
 
 To convert oyster and muscle shells into lime, requires a higher temperature in the kiln than ordinary 
 limestone, and they have a great tendency to produce a badly slaking lime. The gelatin in the shells 
 is converted into charcoal which burns with difficulty, and is long retained in the interior of the stones 
 while the lime is burnt. Now, if burnt lime is heated for some time intimately mixed with charcoal, 
 the basic carbonate is produced — according to Fuchs. 
 
 The slaking. — Burnt lime is of a whitish-gray color, or often dirty white, seldom pure white ; it is 
 much more friable than fresh limestone, but yet sufficiently solid to bear carriage. The crystalline 
 structure of many varieties of lime is often distinguishable after burning. It is light and excessively 
 porous. In consequence of its porosity, burnt lime absorbs water (about 18 per cent.) with the greatest 
 avidity, during which operation tire air contained in the pores is evolved with considerable noise. In a 
 few minutes (but much later with poor lime) the saturated lime is observed to become hot, and from 
 that moment the combination of lime and water proceeds. The lumps of lime fall to pieces with a 
 crackling sound, and the smaller pieces are reduced to powder with the evolution of much steam, until 
 at last the whole is converted, with a greatly increased volume, into a soft uniform white powder, i. e., 
 into hydrate of lime. For building, it is customary to place the lime in slaking tubs, or into flat boxes 
 constructed of boards, with a spout, and to pour as much water into them as will nearly cover the lime. 
 During the slaking of the lime, the excess of water is heated to lively ebullition, and the workmen en- 
 deavor to mix the lime and water in a uniform manner with a hoe. If the proportion of water was 
 correctly estimated, a uniformly thick semi-liquid mass results. In the formation of hydrate of lime, 
 100 parts of pure lime combine with 32 parts of water, or nearly J. 
 
 The conversion of liquid into solid water may be viewed as the proximate cause of the great evolu- 
 tion of heat which accompanies the slaking of lime, inasmuch as the water must be contained in this 
 state in the solid hydrate of lime. Suppose 3 lbs. of lime to be slaked, these will combine with 1 lb. of 
 water, for instance, and convert it into the solid form. In this process, a quantity of heat is liberated 
 sufficient to bring 079 or | lbs. of water to the boiling point. In practice the amount of heat is much 
 greater, for a boiling temperature is attained when the lime is covered with three times the quantity of 
 water. The conversion of water from the liquid to the solid state is, consequently, not the only source 
 of the heat, the remainder must be accounted for by the chemical action which ensues. As a proof of 
 this, the fact may be adduced that lime heats with snow or ice. When a large excess of water is used, 
 the heat evolved is more diffused and less intense ; it increases with a lesser quantity, and attains a 
 maximum when no more is added than enters into combination with the lime. The heat has then been 
 observed to attain the temperature required to ignite sulphur and gunpowder, or even wood. If the 
 lime is moistened with water in the dark, it becomes red-hot and emits a lively luminous appearance; 
 in this case, the heat is concentrated by the surrounding lime which is not in the act of being slaked. 
 The heat is in general so much the more intense the more rapidly the lime is slaked ; or, is in propor 
 tion to its purity and the proper degree of causticity attained in the kiln. The temperature of slaking 
 must always be attended to, as it influences the quality of the lime, and must be regulated by a cautious 
 addition of water; when no more water is added to the lime than it can absorb, it does not form a soft, 
 jut a sandy (coarseR- crystalline) powder, and is said to have been rendered poor by slaking. The 
 
LIME. 
 
 builders have, therefore, a good reason for slaking the lime at once to the form of an impalpable, and 
 not a coarse powder. Rather more than 3 parts of water are required for this purpose. If lime is only 
 speedily dipped in water in a basket, so that it falls to powder, and is afterwards mixed with moie 
 water, it does not increase more than to 2£ volumes; if allowed to fall to powder, exposed to the air, 
 and then made into a paste with water, it will only yield 1'7 volumes. 
 
 Influence of the air . — Exposed to the air, burnt lime is converted very slowly and without any eleva- 
 tion of temperature into a rough, coarse powder, containing small angular pieces ; it then effervesces 
 vigorously with acids. 
 
 As large quantities of lime must be kept ready slaked for the purposes of the builder, and it is neces- 
 sary to protect it from the action of the atmosphere which would render it useless as mortar, it is cus- 
 tomary to preserve it in deep pits. The slaking-tub is placed in front of a pit into which the slaked 
 lime in the semi-liquid state is allowed to flow until the pit is filled. The lime becomes fatter and 
 tougher in the pit, those pieces becoming gradually slaked which resisted the first action of the water. 
 The excess of water collects on the surface and can be removed ; the pit is then covered with a layer of 
 sand two or three inches in thickness, and the lime is thus preserved totally unchanged. In removing 
 the ruins of the castle of Landsberg in order to lay the foundations for a new building, it is stated by 
 Jabn, that a lime-pit of considerable dimensions was found in one of the vaults. The surface of this 
 mass of lime was carbonated to the depth of a few inches, but all below that was in the state of freshly 
 slaked lime, only somewhat more dry. This lime, which was certainly more than 300 years old, and 
 valued at several hundred florins, was consequently used in constructing the new building. 
 
 Hydraulic lime .—' Those varieties of lime which contain about 10 per cent, of silica or silicates, as- 
 sume different properties, and although they are only slowly slaked after burning and poor, yet when 
 made into a dough with water, they soon become solid, and exposed in this state to the constant action 
 of water, acquire a high degree of consistence, and are rendered hard, like stone, without being subse- 
 quently loosened or eaten away by the water, and are very appropriately called hydraulic. As the 
 hydraulic property is solely due to a chemical process, it can only be explained and understood by ref- 
 erence to the chemical nature of the stones. The following are the results of Bertliier’s analyses, witli 
 the exception of the last number, which was analyzed by Kersten : 
 
 The fresh Limestones contained in 100 parts : 
 
 1 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 Carb. of lime 
 
 90-0 
 
 89-0 
 
 89-0 
 
 89-0 
 
 85-8 
 
 82-5 
 
 80-0 
 
 79-2 
 
 76-5 
 
 “ “ magnesia 
 
 5-0 
 
 3'2 
 
 2-0 
 
 2-0 
 
 0-4 
 
 41 
 
 1*5 
 
 2-5 
 
 3*0 
 
 “ “ protox. iron... 
 
 — 
 
 — 
 
 — 
 
 — 
 
 6-2 
 
 — 
 
 — 
 
 6-0 
 
 3-0 
 
 “ “ protox. mang. 
 
 — 
 
 t 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 1-5 
 
 Silica 1 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 17 0 
 
 f>*5 
 
 11-6 
 
 Alumina I 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 1-0 
 
 3-8 
 
 3‘6 
 
 Oxide of iron f 
 
 5-0 
 
 7-8 
 
 90 
 
 9-0 
 
 5-4 
 
 13.4 
 
 
 
 
 
 
 
 Carbon j 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 2-0 
 
 
 
 Water 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 — 
 
 l-o 
 
 — 
 
 — 
 
 The Lime 
 
 obtained by burning the above contained in 100 parts: 
 
 
 
 Lime 
 
 87-0 
 
 84-0 
 
 82-0 
 
 82-0 
 
 83-0 
 
 79-3 
 
 70-0 
 
 74-0 
 
 68-3 
 
 Magnesia 
 
 4-0 
 
 2-5 
 
 L5 
 
 1-5 
 
 — 
 
 8-5 
 
 1-0 
 
 2 0 
 
 2-0 
 
 Clay 
 
 9-0 
 
 13'5 
 
 16-5 
 
 16-5 
 
 7-0 
 
 16-7 
 
 29-0 
 
 17-0 
 
 24-0 
 
 Oxide of iron 
 
 — 
 
 — 
 
 — 
 
 — 
 
 10-0 
 
 — 
 
 — 
 
 7-0 
 
 5-7 | 
 
 The first five numbers yield lime of very moderate, the last four, of a very marked hydraulic chai - 
 acter. It will be seen by the table below, that this property increases with the quantity of matter in- 
 soluble in muriatic acid. This substance consists chiefly of a combination of silica and alumina, but is 
 often composed nearly entirely of silica in the soluble modification. It becomes of great importance to 
 obtain a knowledge of this insoluble portion, as upon it the hydraulic properties depend. This has con- 
 sequently received more attention in recent analyses, as will be seen by the following examples : 
 
 Burnt hydraulic lime is (with few exceptions) soluble in acids ; and, in proof of the presence of a 
 silicate that can be decomposed by acids, a thick jelly of silica is produced. This property of yielding 
 gelatinous silica stands, therefore, in intimate connection with the property of becoming hard under 
 water. Unburnt, pulverized stones do not harden, as is well known ; and hydraulic lime, mixed with 
 water, acquires a certain consistence much before it becomes hard. Moistened hydraulic lime produces, 
 m the first instance, a connected, very soft, friable mass, which is easily scratched by the nail ; at a 
 much later period, this mass, when covered with water, acquires a hardness which is quite equal to, and 
 often exceeds that of, the limestone itself. As a general fact, the time in which different hydraulic lime- 
 stones become hard is very variable, and the chemical action, which is the cause of the hardening, is 
 consequently very unequal. The degree of hardness which they acquire is also not the same ; those 
 that harden slowly are often more compact than those which harden in a shorter time. The time re- 
 quired for hardening varies from a few minutes to weeks and months, and bears some relation to the 
 amount of the aluminous constituent in the lime. The more the limestones contain of this ingredient, 
 the more quickly they harden. The hardening and solidification of the hydraulic stones being, therefore, 
 dependent upon the chemical reaction of their two ingredients, the relative proportions of these cannot 
 be a matter of indifference ; and as there are varieties which, from the smaller quantity of the silicious 
 constituents contained in them, approach the ordinary limestones in properties, so there are others, iif 
 
228 
 
 LIME. 
 
 which this ingredient obtains so great a preponderance, and in which the amount of carbonate of lime ii 
 so small, that they no longer exhibit the hydraulic property. All mineral substances which possess the 
 property of rendering ordinary limestone hydraulic, are very appropriately called cements. 
 
 Contains silicious clay. 
 
 Moderately good 
 hydraulic lime. 
 
 Ordinary hydraulic 
 lime. 
 
 Best hydraulic 
 lime. 
 
 Intermediate lime. 
 
 Bad intermediate 
 cement. 
 
 Ordinary cement. 
 
 Best intermediate 
 cement. 
 
 Transition to Puz- 
 zolana. 
 
 Before burning (to 100 car- ) 
 bonate of lime.) ) 
 
 12 
 
 20 25 
 
 30 
 
 37 
 
 56 
 
 156 
 
 510 
 
 After burning (to 100 caustic ) 
 lime.) ) 
 
 22 
 
 36 | 44 
 
 53 
 
 65 
 
 100 
 
 273 
 
 900 
 
 This division is of course quite arbitrary, no classes existing in nature, but only transitions ; it is, 
 however, convenient when its true signification is borne in mind. There must necessarily be numerous 
 exceptions, for this reason, that the property of hardening in one and the same specimen of lime varies 
 with the temperature at which it has been burnt ; thus several varieties belonging to the third class, 
 when imperfectly burnt (i. e., when the whole of their carbonic acid has not been expelled) yield an hy- 
 draulic lime of the second best quality. Yicat has determined in single cases the amount of imperfect 
 calcination by the amount of carbonic acid not expelled from the lime, and has tested the property ol 
 hardening in these different gradations. Thus one variety of limestone in which the carbonic acid re 
 maining in it 
 
 amounted to 
 
 30 per cent. 
 
 27 per cent. 
 
 26 per cent. 
 
 23 per cent. 
 
 20 per cent. 
 
 10 per cent 
 
 yielded a mortar 
 which hardened in 
 
 15 minutes 
 
 12 minutes 
 
 7 minutes 
 
 9 days 
 
 30 days 
 
 9 days. 
 
 whence it is obvious, that in the course of calcination, and with the increase in the amount of caustic 
 lime, a great diversity of relations between it and the aluminous constituent are created, upon one of 
 which, or upon several at once, the property of rapidly hardening is chiefly dependent. Too much heat 
 in the kiln and incipient fusion, renders the lime very much weaker than it should be when the process 
 is properly conducted, and at last disqualifies it completely. It must be noticed lastly, that hydraulic 
 lime never hardens, when it is immediately immersed in water, before having acquired a certain con- 
 sistence. In this case, the particles never agglutinate properly together, but form a porous mass. 
 
 Many limestones, particularly those which form the boundary between the hydraulic limestones and 
 the cements, possess the very objectionable property of containing portions which slake at a subsequent 
 period, when the greater bulk has already solidified and become hard. The mortar then falls to pieces. 
 and is rendered perfectly useless. It would appear as if particles of lime were in this case so enveloped, 
 as only to become penetrated by the water in the course of the process of hardening. 
 
 Calcination. — Hydraulic lime is burnt in a similar manner to ordinary limestone ; a much less degree 
 of heat, however, is required. Perpetual kilns are used ; the burnt stones are reduced to powder 
 under stampers or ground in a mill ; the powder is passed through a sieve, and is then in a fit state 
 for use. 
 
 Those varieties of hydraulic lime which slake easily, need not even be reduced to powder. A great 
 error is, however, committed in exposing the hydraulic lime (particularly in the state of powder) for 
 any length of time, during carriage, or in warehouses, to the moisture in the atmosphere ; the greater 
 part of its good properties are thus gradually destroyed, and it afterwards hardens very slowly or not 
 at all. It need hardly be mentioned, that a larger stock of hydraulic lime should never be made than 
 is intended for immediate consumption. With reference to this point, Yicat has shown, that hydraulic 
 lime which has once attracted moisture, may be made to set, by renewed pulverization and mixture 
 with water; but the action is much slower, and it is converted into an article of the worst quality. 
 
 Theory of hardening or solidification. — The solidification of hydraulic lime is supposed to be due to 
 the presence and mutual action of the silica and caustic lime contained in it. The final result is derived 
 from two operations. During calcination , the lime is rendered caustic by the evolution of carbonic 
 acid, and this caustic lime then reacts upon the silicious clay, converting it into a compound that is easily 
 decomposed by acids. The excess of caustic lime, as well as the compound into which the silicious 
 clay has been converted, then react upon each other, when mortar is prepared from the ground burnt 
 lime, in such a manner, that a solid stone-like silicate is produced in the humid way. The water here 
 obviously has a double action. Dry substances, like lime and the silicate of alumina, act very little, or, 
 nnder certain circumstances, not at all, upon each other, unless the solvent power of water is employed 
 to bring them into intimate contact. During solidification, the water will constantly transfer the lime 
 which it has dissolved, to the silicious particles ; it will then dissolve fresh lime, which is again om 
 
LIME. 
 
 229 
 
 ployed in the production of the silicate, and so on. The process of solidification is not so much the con- 
 version of a ready formed silicate into a hydrate, as the format ion of a hydrated silicate in one and the 
 same operation. 
 
 The action of the day. — The silica may be replaced, as is indeed the case in the greater number of 
 dydraulic limestones, by different silicates. Amongst these, the clays are the most important. 
 
 The great diversity in the nature of the clays does not admit of the supposition that their action is 
 always the same, but nevertheless they all yield a substance with lime which hardens well, and in some 
 cases affords excellent mortar. All must be previously burnt, particularly potter’s-clay. In some 
 cases, it is necessary to calcine the clay with lime. The common ferruginous brick-earth hardly binds 
 at all with lime when only slightly burnt, but when strongly heated, to the point of incipient fusion, 
 the oxide of iron enters into combination with the clay, aDcl a vei-y powerful solidification then ensues 
 with lime. 
 
 Artificial hydraulic lime . — Artificial mixtures of appropriate silicates with lime, under proper treat- 
 ment, possess the hydraulic property in quite as eminent a degree as the natural productions. Experi- 
 ence has indeed anticipated theory in this fact by several centuries. The Romans were well acquainted 
 with the use of lime-mortar, and applied it both in the construction of buildings and roads ; they also 
 soon made the important discovery that a certain soft, porous, almost earthy rock, containing pumice- 
 stone, and resembling this in composition, and which was found on the coasts of the Bay of Bay® and 
 Naples, particularly in the neighborhood of Puteoli, possessed the valuable property of forming an hy- 
 draulic mortar with burnt lime. They called the rock pulvis Putcolanus ; it is described by Vitruvius 
 and by Pliny, and was employed, mixed with an equal quantity of lime, for building under water. The 
 pulvis Puteolanus was precisely the same substance as is known in the present day under the name of 
 Puzzolana. The modern name of the town Puteoli is Puzzuoli. 
 
 2Vass, or tarras. — After entering Germany, and having taken possession of the Rhine, the Romans 
 soon recognized, in the layers of trass, near Bonn, the well-known pulvis Puteolanus, and opened the 
 quarries, whence this important material is distributed, far and wide, even to the present day. Both 
 Puzzolana and trass are conglomerates of fragments of volcanic rocks, transposed by the agency of 
 water from their original sites ; they'often contain fragments of basalt, pumice-stone, trachyte, clay-slate, 
 &c.. indicating at once the connection of the one with Vesuvius, and of the other with the volcanoes of 
 Eifel. The trass in Brohlthal is derived from the constituents of the trachyte rocks in the neighborhood ; 
 it forms very thick beds, often filling entire valleys, and is in the form of a friable, easily pulverized 
 stone, the color of which is generally light, passing from a yellowish to a greenish hue. It is ground in 
 a number of stamping-mills in the neighborhood, and exported in the form of a fine powder. Like most 
 other volcanic productions, as basalt, klingstein, &c., trass is resolved into two distinct silicates by chem- 
 ical agency. The one is readily soluble in muriatic acid, the other resists solution. 
 
 Puzzolana . — Berthier found the Italian Puzzolana composed of 44’5 per cent, silica, 15 0 alumina, 8'8 
 lime, 4’7 magnesia, 12'0 oxide of iron and titanium, 1'4 potash, 4T soda, and 9’2 water. 
 
 Clay as cement. — All those substances which render fat, slaked lime hydraulic, are called cements. 
 Puzzolana, trass, and all similar cements have the advantage of requiring no preparation by burning, 
 but are capable of acting iii the natural state — of course in fine powder, that they may be properly 
 mixed. All varieties of clay, to be used for cements, must be disintegrated by burning, with or without 
 a certain proportion of lime, according to their different characters. They then afford very powerful 
 cements, which property, however, is very much influenced by the temperature to which they have been 
 exposed, and the manner in which they have been burnt. Treussart made some bricks from a clay 
 which is used in Strasburg for the manufacture of alum, and contains 50 silica, 32’7 alumina, T6 mag- 
 nesia, with mere traces of oxide of iron ; a part of these he burnt in the alum-furnace, and the others in 
 a lime-kiln. When the burnt clays were made into mortar with half their weight of slaked lime, a 
 great difference was observed in the two kinds ; that which had been burnt in the alum-furnace hard- 
 ened in two or three days, and would withstand a weight of 400 pounds without being crushed, while 
 that from the lime-kiln did not harden for thirty days, and, placed in the same circumstances, broke 
 under a weight of fifty or sixty pounds. A similar comparison, instituted with two mortars, also com- 
 posed of one part slaked lime and two parts cement, the one of which consisted of simple clay, the 
 other of clay that had been calcined with 2 per cent, of lime, led to the same result in favor of the latter 
 mortar, which hardened in 17 days, while the former required 30 days. 
 
 The excellent hydraulic mortar of Tournay, known under the name of “ cendree ,” is prepared from 
 the refuse which is left on burning the lias limestone. This waste, which remains after removing the 
 lumps oi lime, consists of small fragments of lime and of the ash, (the coal there used yielding a large 
 amount of ash,) in about the proportions of 1 : 3. The mixture is slaked in a small quantity of water, 
 and before being used is well beaten and worked about. 
 
 Dr. Eisner has published the following analyses of certain iron slags which are found to afford excel- 
 lent hydraulic mortar when mixed with burnt lime : 
 
 
 I. 
 
 II. 
 
 Silica 
 
 
 40*44 
 
 Alumina 
 
 
 15-38 
 
 Lime 
 
 
 33-10 
 
 Protoxide of manganese 
 
 
 4-40 
 
 Protoxide of iron 
 
 1-25 
 
 1-63 
 
 Potash 
 
 
 2-07 
 
 Sulphur 
 
 
 o-7 e 
 
 These slags in the state of fine powder, when treated with a small quantity of muriatic acid, are 
 rapidly converted into a uniform gelatinous mass. 
 
 It is easy to ascertain whether a slag is suited for the production of hydraulic cement, by pouring 
 
230 
 
 LINK-MOTION. 
 
 over it, in the state of fine powder, a small quantity of hydrochloric acid ; if it forms a gelatinous mass 
 after a short time, it will then yield, with lime, a proper mixture for hydraulic mortar. 
 
 Roman cement. — It is a remarkable fact in the history of hydraulic mortars, which originates, as we 
 have seen, with the Puzzolana and trass employed by the Romans, that the more the knowledge of 
 their uses has been spread, the more substances have been discovered which either act as hydraulic 
 mortars themselves, or can be mixed as cements in the preparation of artificial mortar ; so that what 
 appeared originally a privilege accorded to a few favored spots only, can now be obtained almost 
 everywhere. A strong inducement to study the nature and modes of occurrence of hydraulic lime was 
 created by the patent granted to Parker and Wyatt, in London, in the year 1796, for what they termed 
 “ Roman cement.” The material employed in the manufacture of this cement are the nodules, of an 
 ovoidal or globular form, which are found in the London clay, and known by the name of Septaria. 
 They are calcined in perpetual lime-kilns with coal, in which a very moderate and well-regulated heat 
 is carefully preserved. After calcination, the stones are ground under heavy edgestones to a very fine 
 powder, which is sifted, and then packed in casks for sale. These nodules are found in many localities 
 in this country. 
 
 Roman cement is one of the most powerful hydraulic mortars, and is exceedingly valuable, not only 
 on account of the rapidity with which it hardens, and this is effected in a very few minutes, but because 
 when hardened in considerable masses it is not liable to crack. 
 
 All artificial or natural hydraulic limestones are soluble (before as well as after calcination) in mu- 
 riatic acid with the separation of silica, except when sand or some similar substance has been added 
 lo them. 
 
 The hydraulic limestones, when they do not contain a sufficient quantity of lime to be capable of 
 slaking with water, must be very finely pulverized ; it is only by this high state of division that a 
 proper action can ensue. A thorough penetration of the silicious portion by the lime is never entirely 
 effected, but a certain proportion remains inclosed and removed from the sphere of action. See 
 Mortar. 
 
 LINK MOTION. — Variable expansion gear, now generally used on locomotives for the movement cl 
 the steam valves, first invented by Mr. Williams of Newcastle. Williams’ incipient link was a slotted 
 straight bar, which connected the straps of the fore and hack eccentrics, formed with ears to secure the 
 linking pins. In the slot of the link, a slide-block hung on the end of a radius link from the valve spin- 
 dle, was adjustable towards one end or the other, to receive the motion of the one or the other eccentric 
 for fore or back gear ; while the link would partake jointly of the two motions of the eccentrics, its hor- 
 izontal motion would be smallest at the centre of its length, and increase towards the extremities : thus 
 by shifting the block towards the centre, the travel of the valve would be reduced, and variable expan- 
 sion thereby obtained. 
 
 The objections to the special arrangement here proposed are obvious ; the idea has however been de- 
 tffoped by Mr. Howe, into the more practicable arrangement first applied to the engines of Robert 
 'Mephenson & Co. in 1843, and from this time the link has been adopted generally by all other English 
 
 manufacturers. 
 
 Link motions are all of two classes, in which, 
 first the link is suspended directly from a fixed point 
 as a stationary link, fig. 2601 ; secondly, the link 
 is movable vertically, (fig. 2602,) carrying with it 
 of course, the eccentric rods which are directly con- 
 nected to it. In the first class, therefore, the va- 
 riable expansion is accomplished by shifting the' 
 sliding blocks in the link : in the other class, the 
 link is shifted upon the block. The link itself is 
 employed under three general forms, distinguished 
 as much by structural characteristics as by pecu- 
 liarity of action. The box link, the open link 
 joined to the eccentric-rods at the extremities, and 
 the open link joined behind. The box-link, fig. 
 2598, is formed in two halves or sides bolted to- 
 gether at the extremities, enclosing a rectangular 
 recess for the reception of the block as shown in section. The eccentric-rods are attached to the 
 extreme stud pins, forged on the outside of the link, and thus a clear way is obtained for the 
 blocks from one end of the link to the other ; they may be shifted even to a position concentric 
 with the eccentric rod ends. The two forms of open fink are adopted with a view to simplify the 
 parts, the one (fig. 2600,) with the extreme connections, is the form first used by Stephenson; by 
 its form it does not pei-mit of the block being placed concentric with the eccentric rod ends, the range 
 being so limited, it is plain that the block never can receive and transmit the full throw of the ec- 
 centric to the valve, a feature in which the box-link has the advantage. With this link the throw of 
 the eccentrics and therefore their diameters, must be greater than those required by the box-link for a 
 given maximum travel of valve. The third form of link, (fig. 2599,) connected behind, permits of the 
 same freedom for the block that is yielded by the box-link ; the block may be shifted to a position level 
 with the point of attachment at which it may transmit the whole throw of the eccentric. The over- 
 hung nature of this knuckle-jointed sort of link, and its peculiarly irregular movements in consequence, 
 render it a more ticklish variety than the others ; as, however, it combines the advantage of the box- 
 link in respect of the transmission of the whole motion, with the simplicity of the other link, it is now 
 most commonly employed, at least in locomotives, where vertical clearance is limited. 
 
 The first qualifications of expansion gear are to insure for every variation of expansive action, a free 
 admission and free release for the steam ; to render the periods of admission equal for the front and back 
 
LINK-MOTION. 
 
 231 
 
 itrokes, and to promote the expansive action of the steam sufficiently to extract the most if not the whok 
 of its works for propulsion, excepting a per centage required for the purposes of the blast. 
 
 2G00. 
 
 Lead. In the stationary link-motions, a constant lead throughout the forward and backward gear 
 is obtained by circling the link to the radius of the valve-rod link, and the same lead may be for the 
 front and back strokes. In the shifting link motion, the lead essentially varies with the expansion, the 
 greater the degree of expansion — that is, the less the admission the greater also is the lead; the lead 
 is thus least in full gear, and attains its maximum in the mid gear ; it may however always be made the 
 same for the front and back strokes, and thus equality is obtained by circling the link to the radius of 
 the eccentric rod. Thus the conditions of constant lead and varying admission which are incompatible 
 with the nature of the shifting link, motion are obtainable by the stationary link with a single valve. 
 The longer the eccentric-rod, and the shorter the link, the less is the variation of lead in the shifting- 
 link motion. The shifting-link motion may with advantage be set with the desired lead in half gear, 
 which is the most ordinary working position of the mechanism ; the evil of varying lead is thus divided 
 and reduced. 
 
 Linear Advance. With the stationary link the linear advance of the eccentrics is in all cases less than 
 that of the valve, and is a quality affected by the length of the eccentric-rods; these rods by their 
 varying obliquity increase the advance while transmitting it to the link, and the shorter the rods the 
 greater is the difference so caused. With the shifting-link, the linear advance of the valve is in all cases 
 equal to that of the eccentrics in full gear, independent altogether of the length of the rods — expressly 
 meaning by full gear, that the fore rod end is brought into the centre line of the valve rod ; in other po- 
 sitions, however, the linear advance of the valve varies precisely with the lead, as the lead, in fact, partly 
 constitutes the advance. 
 
 The Motion of the Unk. The motion of the link is composed of the distinct motions of the ec- 
 centrics, and every part of the link is subject to this compound influence. The motion of each 
 eccentric prevails in that half of the link to which it is coupled, and at the centre the motion of the 
 link is equally composed of the two. The final result of this combined action is approximately the 
 same as that available by the action of a single eccentric of variable throw. Thus the object which 
 was proposed to be obtained by the spiral and wedge reversing motions of Fenton and Dodd's variable 
 expansion, with (if possible) constant lead, is realized in the simplest manner by the combined operation 
 of two eccentrics, and with an efficiency and precision which probably the original promoters of the 
 link motion did not anticipate. Horizontal motion communicated to the link by the joint action of the 
 eccentrics is a minimum at the centre of its length, where it is equal to twice the linear advance, and 
 it increases towards the extremities various periods of the block in the link, or of the link on the block, 
 on the general principle that admission varies with the travel of the valve. The distribution derived 
 from the link is affected by the lengoh of the connecting-rod relative to that of the crank ; the shorter 
 the rod, the greater is the front admission, and the less is the admission for the back stroke ; therefore 
 the term “ link-motion ” in so far as it involves the relation of the valve’s motion to that of the piston, 
 virtually includes the proportions of the piston motion. The quality of the motion derived from the 
 link is modified by the positions of the working centres, and most especially of the centres of suspension 
 and connection ; the centre of suspension is the most influential of all in regulating the admission, and 
 its transition horizontally is much more efficacious than a vertical change of place to the same extent. 
 The periods of admission in half gear are much more sensitive to variation by mode of suspension and 
 connection than those in full and mid gear. It is expedient to set the motion right for this position as 
 regards the quality of the admissions, because these differences for other positions are then inconsiderable. 
 There are certain neutral positions of the centre of the suspension, on which the link in vibrating yields 
 equal admissions, and these may be found for any specific arrangement by the method of three trails. 
 These neutral positions may be located either in the centre line of the link, vertically or horizontally 
 in the neighborhood of the middle of the link. As the vertical movement of the body of the link with the 
 consequent slip between the link and the block is the least possible when the suspended centre lies in 
 the centre line of the link, increasing as the centre is removed laterally, the centre line of the link is, in 
 this respect, the most favorable locality for the suspension, though not always practicable for equal admis- 
 sions. It has been found that the stationary and shifting links have not the same neutral centres of sus- 
 pension; that in general the stationary link should be hung by a centre in the neighborhood of the mid- 
 dle of its length, and the shifting link towards one of the extremities. The periods of expansion and release 
 
232 
 
 LITHOGRAPHY. 
 
 increase as those of admission are diminished, and when the points of suppression are equally adjusted 
 those of release do not considerably differ. It has been found in short, that in valves the admissions and 
 the expansions may be made absolutely identical, as in the Great Western link, fig. 2601. An admission 
 of 75 per cent, or three-fourths of the stroke is attended with a mean expansion of 16 percent, of expan- 
 sion, exhausting at 80 per cent. The utmost period of expansion obtained by a stationary link in mid 
 gear is 38 per cent, for 12 per cent, of admission, in which case the steam is cut off at less than one- 
 eighth of the stroke, and expanded into a volume of 50 per cent., or one half stroke 4 times the initial 
 volume exclusive of clearance, after which it exhausts during the remaining half stroke. With the 
 stationary link the shortest admission is 1 1 per cent., or one-ninth of the stroke, expanding into 50 per 
 cent., or 44 times the initial volume, before the release takes place. With the shifting-link, the smallest, 
 attainable admission is about 17 per cent., or one-sixth of the stroke ; this is about one-half more than 
 what is obtained by the stationary link, the difference being due to the excess of lead yielded by the 
 shifting. As the release takes place at half stroke, the shifting-link cannot expand the steam above 
 three times its initial volume, exclusive of clearance. The average period of admission in full gear 
 does not exceed 75 per cent., or three-fourths of the stroke, according to the examples before us. More 
 than this should not be required, nor indeed could it be beneficially employed at regular speed ; the ad- 
 mission may, however, be increased by forcing the mechanism of the valve beyond full gear ; that is, by 
 causing the block to woi’k in the extreme overhung parts of the link, which must be extended for the 
 purpose beyond the centres of connection* by .this expedient the throw of the valve is increased, and it 
 is practicable with the box and back hug links, and may in many cases be usefully employed when a 
 ready start with a heavy train is required. 
 
 The open link connected by its extremities in its own centre line, is identical in its motions with the 
 box-link : in the use of that fink it is imperative that the throw of the eccentric should be greater than 
 that designed for the valve, as in full gear the block is of necessity placed nearer to the centre of the 
 link than the rod centres. 
 
 LITHOGRAPHY. The art of transferring from stone writings or drawings made thereon, which is 
 of quite modern invention. Unlike other kinds of printing, this is strictly chemical, and is in conse- 
 quence called, in Germany, chemical printing. A drawing is made on the stone, either with ink con- 
 taining oleaginous matter, or with chalk containing similar substances, but in a more concentrated and 
 indurated state. The drawing is then washed over with water, which sinks into those portions of the 
 stone that are untouched with the grease of the drawing. A cylindrical roller, charged with printing- 
 ink, is then passed all over the stone, and while the drawing receives the ink, the rest of the stone is 
 preserved from it by the water, on account of the greasy nature of the ink. This art is said to have 
 been invented by mere accident, by Alois Senefelder, of Munich. 
 
 The stones, and the manner in which they are prepared to receive the drawings . — The stone most used 
 in England is found at Corstan, near Bath ; it is one of the white lias beds, but not of so fine a grain, 
 nor so close in texture as the German stone, and therefore inferior ; but it is good for transfers, and does 
 tolerably well for ink drawings or writings. All calcareous stones may be used in lithography, be- 
 cause they imbibe grease and moisture ; but a stone entirely calcareous does not answer well : there 
 should be a mixture of alumina and silex. One of the most certain indications of lithographic properties 
 is the conchoidal fracture ; all stones of this kind will be found good, if they are also hard, have the 
 fineness of grain, and the homogeneousness of texture that are necessary. It is, however, said that none 
 have yet been found equal to those obtained froni the quarries of Solenhofen, near Pappenheim, in 
 Bavaria, and that the lithographers of eminence in Paris use no other. In order to sustain the pressure 
 used in taking impressions, a stone, 12 inches square, ought not to be less than 1 j inch thick, and this 
 thickness should increase with the area of the stone. The stones are first sawn to a proper size, and are 
 then ground smooth and level by rubbing two of them face to face, with water and sand. They must 
 be very carefully examined with a straight-edge, to ascertain that they are perfectly level in every 
 direction. This applies only to the side which is afterwards to receive the drawing, as the natural di- 
 vision of the stone is sufficiently true for the back. When the stones have thus been ground perfectly 
 level, they are well washed, to free them from any of the coarser grains of sand which may have been 
 used in smoothing them. They are then placed on a board over a trough, and they are again rubbed 
 face to face with sand and water, but with a sand of much finer texture than that previously used. The 
 greatest care must be taken to have the sand sufficiently fine ; and for this purpose it must be sifted 
 through a small close sieve, as a single grain of sand of a coarser texture than the rest will scratch the 
 stone, and these scratches will afterwards appear in the impression taken from the stone. When the 
 stones have been rendered sufficiently fine, and their grain sufficiently smooth, they must then be care- 
 fully washed and afterwards wiped dry with a clean soft cloth. This is the plan adopted to prepare 
 the stones for chalk drawings, but to prepare them for ink drawings or writings the following method is 
 the best : After the process just described has been completed, the stones are well washed to get rid of 
 the sand, and they are then rubbed together, face to face, with powdered pumice-stone and water. 
 After they are made perfectly smooth, they are again washed and wiped dry, and are then separately 
 polished with a large piqpe of pumice-stone. 
 
 To clean the stones after they have been fully used, sand is strewed over the surface, which is sprinkled 
 with water and rubbed with another stone, until the writing or drawing upon it has completely disap- 
 peared. It must then be washed in aquafortis, diluted with twenty times its bulk of water, and the 
 stone is then prepared for a new drawing or writing, by being rubbed with fine sand or pumice-stone as 
 before. The longer drawings remain on stones the deeper the ink or the chalk penetrates into their 
 substance, and consequently the more of the stone must be ground away to remove them; this is also 
 more necessary with iuk drawings or writings than with chalk, owing to the greater fluidity and conse- 
 quent penetrability of the former. 
 
 The substances used by the artist upon the stone are either lithographic ink or lithographic chalk. 
 
LITHOGRAPHY. 
 
 233 
 
 The ink for making transfers should be somewhat less burned, and therefore softer than that used 
 for writing or drawing directly upon the stone. 
 
 Lithographic chalk should have all the qualities of a good drawing crayon. It should be even in 
 texture, and carry a good point. The following proportions are recommended : 1 J oz. of common soap, 
 2 oz. tallow, 2-J oz. virgin wax, 1 oz. shelldac. The rest of the process is the same as in making the ink. 
 Less black should be mixed with the chalk than with the ink, its only use being to color the drawing, 
 that the artist may see the lines he traces. When the whole is well mixed it should be poured into a 
 mould and very strongly pressed, to expel any air that may collect in bubbles, which would render it 
 spongy. 
 
 Mode of drawing. — Previous to drawing or writing, the stone must be well wiped with a clean dry 
 cloth. The ink is rubbed with water, like Indian ink, and is almost wholly used on the polished stone. 
 The chalk is used only upon the grained stone ; the polished surface of the other would not hold it. 
 In drawing with ink, a gradation of tints is obtained either by varying the thickness of the lines, or 
 their distances from one another, as in engraving. The ink lines on polished stones, being solid and un- 
 broken throughout, receive the printing all over ; and if the lines be drawn as fine and as uniform as 
 they are usually on copper, the print from them will be in no respect inferior ; but it requires a greater 
 degree of skill to execute as well upon stone as is usually done upon copper or steel. 
 
 In using chalk, the grained stone should be very carefully dusted, and the utmost attention be paid 
 to prevent any lodgment of the smallest particle of grease upon the surface ; personal cleanliness is 
 therefore absolutely necessary to the perfection of his work, especially in chalk drawings. The chalk 
 is used upon the stone precisely in the same manner as crayon upon paper ; but it is of essential ad- 
 vantage in lithography to finish the required strength of tint at once, instead of going over the work a 
 second time, the stone being impaired in its ability to receive the second lining clearly, by the absorp- 
 tion of the first. Some practice is requisite to use the chalk cleverly, as there has been no chalk hith- 
 erto made that will keep so good a point as is desirable. There is likewise some difficulty experienced 
 in obtaining the finer tints sound in the impression ; and in order to obtain the lighter tints properly, it 
 will be necessary to put the chalk in a rest, as the metal-port crayon is too heavy to draw upon the 
 stone. A good lithographer is in the habit, before he commences his subject, of pointing 20 or 30 
 pieces of chalk, stuck in quill-holders, and placing them beside the stone in a little box, taking them 
 up successively as the points become worn off, so as to avoid, if possible, the cutting off chalk during 
 the work, which endangers the soiling of the stone. When a very sharp and delicate line is required, 
 he sharpens the point of the chalk upon paper, by pushing it forward in an inclined position, and 
 twirling it round at the same time between the fore-finger and thumb. As the chalk softens. by the 
 warmth of the hand, it is quite necessary to have several pieces, to be able to change them. Some 
 artists cut their chalk into the wedge form, as being stronger. Those portions that break off in drawing 
 should be carefully taken off the stone by a camel-hair brush. 
 
 Preparation of the stone for printing . — The drawing being finished on the stone, it is sent to the 
 lithographic printer, on whose knowledge of his art depends the success of the impressions. The first 
 process is to etch the drawing, as it is called. This is done by placing the stone obliquely on one edge, 
 over a trough, and pouring over it very dilute nitric acid. It is poured on the upper part of the stone, 
 and runs down all over the surface. The stone is then turned and placed on the opposite edge, and the 
 etching water being collected from the trough, is again poured over it in the same manner. The degree 
 of strength, which is usually about one per cent, of acid, should be such as to produce a very slight 
 effervescence ; and it is desirable to pass the etching water two or three times over the darkest parts of 
 the drawing, as they require more etching than the lighter tints. Experience alone can, however, guide 
 the lithographer in this department of the art, as different stones and different compositions of chalk 
 will be differently acted upon by the acid, and chalk drawings require a weaker acid than the ink. The 
 stone is next to be carefully washed by pouring clean rain-water over it, and afterwards with gum- water ; 
 and, when not too wet, the roller charged with printing ink is rolled over it in both directions, sideways, 
 and from top to bottom, till the drawing takes the ink. It is then well covered over with a solution of 
 gum-arabic i'n water, of about the consistency of oil. This is allowed to dry, and preserves the draw- 
 ing from any alteration, as the lines cannot spread, in consequence of the pores of the utcne being filled 
 with the gum. After the etching it is desirable to leave the stone for a day, and not more than a week, 
 before it is printed from. The effect of the etching is first to take away the alkali mixed with the chalk 
 or ink, which would make the drawing liable to be affected by the water, and, secondly, to make the 
 stone refuse more decidedly to take any grease. The gum assists in this latter purpose, and is quite 
 essential to the perfect preparation of the surface of the stone. 
 
 Printing. — When the intention is to print from the stone, it is placed upon the platen or bed of the 
 press, and a proper sized scraper is adjusted to the surface of the stone. Rain-water is then sprinkled 
 over the gum on the stone, which being dissolved gradually, and a wet sponge passed lightly over all, 
 the printer works the ink, which is on the color-table placed beside him, with the roller in all directions, 
 until it is equally and thinly spread on the roller. The roller is then passed over the whole stone, care 
 being taken that the whole drawing receives a due portion of ink ; and this must be done by giving the 
 roller an equal motion and pressure, which will of course require to be increased if the drawing does 
 not receive the ink readily. When the drawing is first used it will not receive the ink so readily as it 
 will afterwards ; and it is frequently necessary to wet the stone, and roll it several times, before it will 
 take the ink easily. After this takes place care must be taken not to wet the stone too much ; the 
 dampness should not be more than is necessary to prevent the ink adhering to the stone where there is 
 no drawing. After the drawing is thus rolled on, the sheet of paper is placed on the stone, and the im- 
 pression taken. Upon taking the paper off the stone, the latter appears to be quite dry, owing to the 
 paper having absorbed the moisture on the surface ; it must therefore be wetted with a sponge, and 
 again rolled with ink, the roller having been well worked on the color-table before being applied 
 During the printing some gum must always remain on the stone, although it will not be visible, other 
 
234 
 
 LITHOGRAPHY. 
 
 wise the ink will he received on the stone as well as on the drawing, by which the latter would 1>« 
 spoiled; so that if by too much wetting, or by rubbing too hard with the sponge the gum is entirely 
 removed, some fresh gum-water must be laid on. If the stone has in the first instance been laid by with 
 too small a quantity of gum, and the ink stains the stone on being first applied to it, gum-water must 
 be used to damp the stone, instead of pure water. Sometimes, however, this may arise from the 
 printing-ink being too thin, as will afterwards appear. If some spots on the stone take the printing-ink, 
 notwithstanding the above precautions, some strong acid must be applied to them with a brush, and, 
 after this is washed off, a little gum-water is dropped in the place. A steel point is here frequently 
 necessary to take off the spots of ink. The edges of the stone are very apt to get soiled, and generally 
 require to be washed with an old sponge after rolling in ; they must also frequently have an application 
 of acid and gum, and sometimes must be rubbed with pumice-stone. If an ink is too thin, and formed 
 of a varnish not sufficiently burned, it will soil the stone, notwithstanding the proper precautions are 
 taken of wetting the stone, and preparing it properly with acid and gum ; and if, on the other hand, the 
 ink is too thick, it will tear the lighter tints of the chalk from the stone, and thus destroy the drawing. 
 The consideration of these circumstances leads at once to the 
 
 Principles of the printing. — The accidents just mentioned arise at the extreme points of the scale at 
 which the printing-inks can be used, for it is evident that the only inks that can be used are those 
 -which are between these points ; that is, thicker than that which soils the stone, and, at the same time, 
 thinner than that which takes up the drawing. Lithographers are sometimes unable to print in very 
 hot weather, the reason of which may be deduced from the foregoing. Any increase of temperature 
 will diminish the consistency of the printing-ink; the stone will therefore soil with an ink which could 
 be safely used at a lower temperature — hence a stiffer ink must be used. Now, if the temperature 
 should increase so much that the stone will soil with any ink at all less thick than that which will take 
 up the drawing, it is evident that the printing must cease till a cooler temperature can be obtained ; 
 for as the drawing-chalk is affected equally with the printing-ink, the same ink will tear up the drawing 
 at the different degrees of temperature. This, though it sometimes occurs, is a rare case ; but it shows 
 that it is desirable to draw with a chalk or ink of less fatness in summer than in winter, and also that if 
 the printing-room is in winter artificially heated, pains should be taken to regulate the heat as equally 
 as possible. 
 
 Other difficulties in printing, not referable to the foregoing general principle. — If the pressure of the 
 scraper be too weak, the ink will not be given off to the paper in the impression, although the drawing 
 has been properly charged with it. Defects will also appear from the scraper being notched, or not 
 correctly adjusted, or from any unevenness in the leather or paper. After printing a considerable num- 
 ber of impressions, it sometimes happens that the drawing takes the ink in dark spots in different parts. 
 This arises from the printing-ink becoming too strongly united with the chalk or ink of the drawing, 
 and if the printing be continued, the drawing will be spoiled. The reason of this is easily ascertained. 
 The printing-ink readily unites with the drawing, and being of a thinner consistency, it will, by repeated 
 applications, accumulate on the lines of the drawing, soften them, and make them spread. In this case 
 it is necessary to stop the printing, and let the stone rest for a day or two, for the drawing to recover 
 its proper degree of hardness. If the drawing should run smutty from any of the causes before enu- 
 merated, the following 
 
 Mixture for cleaning the drawing while printing must be used: Take equal parts of water, spirits of 
 turpentine, and oil of olives, and shake them well together in a glass vial until the mixture froths ; 
 wet the stone and throw this froth upon it, and rub it gently with a soft sponge. The printing-ink will 
 be dissolved, and the whole drawing will also disappear, though, on a close examination, it can be dis- 
 tinguished in faint white lines. On rolling it again with printing-ink the drawing will gradually re 
 appear, as clear as at first. 
 
 Bleached paper unfit for lithographic printing. — Accidents sometimes occur in the printing from the 
 qualities of the paper. If the paper lias been made from rags which have been bleached with oxy- 
 muriatic acid, the drawing will be incurably spoiled after thirty impressions. Chinese paper has some- 
 times a strong taste of alum ; this is so fatal as sometimes to spoil the drawing after the first impression. 
 When the stone is to be laid by after printing, in order that it may be used again at a future period, 
 the drawing should be rolled in with a 
 
 Preserving ink — as the printing-inks would, when dry, become so hard that the drawings would not 
 take fresh printing-ink freety. The following is the composition of the printing-ink : Two parts of thick 
 varnish of linseed oil, four parts of tallow, one part of Venetian turpentine, and one part of wax. These 
 must be melted together, then four parts of lamp-black, very carefully and gradually mixed with it ; 
 and it must be preserved for use in a close tin box. 
 
 Autographic ink, or that which is suitable for transferring on to the stone the writings or drawings 
 which have been executed on paper prepared for that purpose, should possess the following properties : 
 The ink ought to be mellow, and somewhat thicker than that used immediately on stone ; so that when 
 it is dry on the paper, it may still be sufficiently viscous to cause adherence to the stone by simple 
 pressure. The following is the composition: Dry soap, and white wax free from tallow, each 100 
 drachms, mutton suet, 30 drachms, shell-lac and mastic, each 50 drachms, lamp-black, 30 to 35 drachms ; 
 these materials are to be melted together. 
 
 Autographic paper. — The operation by which a writing or drawing is transferred from paper to stone, 
 not only affords the means of abridging labor, but also of producing the writings or drawings in the 
 same directions in which they have been traced ; whereas, when they are executed immediately on 
 stone, they must be performed in a direction opposite to that which they are eventually to have. 
 Thus it is necessary to draw those objects on the left, which, in the impression, are to be on the right 
 hand. To acquire the art of reversing subjects when writing or drawing, is both difficult and tedious: 
 while, by the aid of transparent, and of autographic paper, impressions may be readily obtained in the 
 same direction as that in which the writing or the drawing has been made. In order to make a transfer 
 
LITHOGRAPHY. 
 
 
 on to stone of a writing, or drawing in lithographic ink, or in crayons, or an impression from a copper 
 plate, it is necessary, 1st, that the drawing or transcript should be on a thin and flexible substance, such 
 as common paper ; 2d, that it should be capable of being easily detached from this substance, and 
 transferred entirely on to the stone, by means of pressure. But as the ink with which a drawing is 
 traced penetrates the paper to a certain depth, and adheres to it with considerable tenacity, it would be 
 difficult to detach them perfectly from each other, if, between the paper and the drawing, some sub- 
 stance was not interposed, which, by the portion of water which it is capable of imbibing, should so fai 
 lessen their adhesion to each other, that they may be completely separated in every point. It is to 
 effect this that the paper is prepared, by covering it with a size, which may be written on with facility, 
 and on which the finest lines may be traced without blotting the paper. Various means may be found 
 of communicating this property to paper. The following preparation has always been found to succeed, 
 and which, when the operation is performed with the necessary precautions, admits of the finest and 
 most delicate lines being perfectly transferred, without leaving the faintest trace on the paper. For 
 this purpose, it is necessary to take a strong, unsized paper, and to spread over it a size prepared of 
 .the following materials : starch, 120, gum-arabic, 40, and alum, 21 drachms. A moderately thick paste 
 is made with the starch, by means of heat ; into this paste is thrown the gum-arabic and the alum, 
 which have been previously dissolved in water, and in separate vessels. The whole is mixed well to- 
 gether, and it is applied warm to the sheets of paper, by means of a brush, or a large flat hair-pencil. 
 The paper may be colored by adding to the size a decoction of French berries, in the proportion of ten 
 drachms. After having dried this autographic paper, it is put into a press, to flatten the sheets, and 
 they are made smooth by placing them, two at a time, on a stone, and passing them under the scraper 
 of the lithographic press. If, on trying this paper, it is found to have a tendency to blot, this inconve- 
 nience may be remedied by rubbing it with finely powdered sandarac. Annexed is another recipe, 
 which will be found equally useful, and which has the advantage of being applicable to thin paper, 
 which has been sized. It requires only that the paper be of a firm texture : namely, gum-tragacanth, 
 4 drachms ; glue, 4 ; Spanish- white, 8 ; and starch, 4 drachms. 
 
 The tragacanth is put into a large quantity of water to dissolve, thirty-six hours before it is mixed 
 with the other materials ; the glue is to be melted over the fire in the usual manner. A paste is made 
 with the starch; and after having, whilst warm, mixed these several ingredients, the Spanish-white is 
 to be added to them, and a layer of the sizing is to be spread over the paper, as already described, tak- 
 ing care to agitate the mixture with the brush to the bottom of the vessel, that the Spanish-white may 
 be equally distributed throughout the liquid. We will hereafter point out the manner in which it is 
 necessary to proceed, in order to transfer writings and drawings. There are two autographic processes 
 which facilitate and abridge this kind of work when it is desired to copy a fac-simile, or a drawing in 
 lines. The first of these methods is to trace, with autographic ink, any subject whatever, on a trans- 
 parent paper, which is free from grease and from resin, like that which, in commerce, is known by the 
 name of papier vegetal, and to transfer it to stone ; this paper to be covered with a transparent size : 
 this operation is difficult to execute, and requires much address, in consequence of the great tendency 
 which this paper has to cockle or wrinkle when it is wetted. Great facilities will be found from using 
 tissue paper, impregnated with a fine white varnish, and afterwards sized over. In the second process, 
 transparent leaves, formed of gelatin, or fish glue, are employed, and the design is traced on them with 
 the dry point, so as to make an incision ; these traces are to be filled up with autographic ink, and then 
 transferred. We will describe, in their jrroper places, these processes, as well as that of transferring a 
 lithographic or a copper-plate engraving. 
 
 Autographic processes. — To transfer a drawing or writing to stone, it is made with ink on paper, both 
 prepared in the way we have described. A crayon drawing may, on an emergency, be executed auto- 
 graphieally ; but this mode of procedure is too imperfect to admit of procuring, by its means, neat and 
 perfect proofs ; besides, it is as expeditious to draw immediately on the stone. 
 
 In order to write, or to draw on autographic paper, a little of the ink of which we have given the 
 composition is diluted with water, taking care to use only rain-water, or such as will readily dissolve 
 soap. The solution is facilitated by slightly warming the water in the cup ; and the ink is dissolved by 
 rubbing the end of a stick of it in the manner practised with Indian ink. There should be no more dis- 
 solved at a time than will be used in a day, for it does not redissolve so well, neither is the ink so 
 good, particularly for delicate designs, after it has been left to dry for several days. This ink should 
 have the consistence of rather thick cream, so that it may form very black lines upon the paper : if these 
 lines are brown, good impressions will not be obtained. A sheet of white paper is placed under the 
 hand while writing, in order that it may not grease the autographic paper. 
 
 The stone used for autography should be polished with pumice-stone, and the impressions will be 
 neat in proportion as the stone is well polished. Autographic work may be executed either cold or 
 warm ; that is, taking the stone at its ordinary temperature, or making it warm by placing it near to 
 the fire, or exposing it to the heat of the sun : if the first means of warming be used, care must be taken 
 that the fire be not too hot, or it will crack the stone ; the temperature given to it should be about that 
 of an earthen vessel filled with lukewarm water. The work may be done, though less perfectly, with- 
 out warming the stone. AVhen the stone is thus prepared, it is fixed in the press, and the paper on which 
 the writing is made is applied to it. The stone may be rubbed with a linen cloth, slightly moistened 
 with spirits of turpentine ; and in every case it is necessary that it be made perfectly clean. The tur- 
 pentine is left to evaporate ; and from five to eight minutes before the paper is applied, it is wetted 
 with a sponge and water on the reverse side to that on which the writing is done, so that the moisture 
 may penetrate throughout every part. The water, however, must not appear on the paper when it is 
 about to be laid on the stone ; but any superabundance which may remain on it must be removed by a 
 pressed sponge. When the paper is brought to the proper state, it is taken by both hands at one of its 
 extremities, and placed lightly and gradually upon the stone, so that there may be no plaits formed in 
 it, and that it may be equally applied over its whole surface. Care must be taken so to fix the scraper 
 
* 
 
 236 
 
 LITHOGRAPHY. 
 
 Hut it may bear steadily on the autographic paper ; for if it removes it at all it will change the place 
 of pressure, and the lines will be doubled. There should be at hand five or six sheets of very even 
 mackle paper, so that they may be changed with each impression. The paper on which the writing oi 
 drawing is made being placed on the stone, it is covered with a sheet of mackle paper, and subjected 
 to a slight action of the press ; then to a second, a third, or even to more, until it is believed that the 
 writing is perfectly transferred. At each stroke of the press the mackle paper, which has imbibed 
 moisture, is withdrawn, and a dry sheet substituted in its place. All these operations require to be 
 performed with expedition and dexterity, particularly when the stone is warm. The next thing is to 
 detach the autographic paper, which will be found adhering closely to the stone. To effect this, it is 
 well wetted with a sponge, so that every part of it may be perfectly penetrated by the water; it may 
 then be removed with facility, entirely detached from the writing, which will remain adhering strongly 
 to the stone. If this operation, which requires much practice, be well performed, there will not be found 
 the slightest trace of ink remaining on the paper. Should there be any lines not well marked on the 
 stone, they may be retouched with a pen ; or, which is better, with a hair-pencil and ink ; but when 
 this is done, care must be taken that the stone is quite dry. A part of the sizing of the paper may be 
 found dissolved and adhering to the stone ; this may be removed by washing or slightly rubbing it with 
 a wet sponge. The stone is then prepared with aquafortis, and the impression taken. 
 
 Autography is not confined to the transferring of writings or drawings done with autographic ink ; by 
 its means a transfer may be obtained from a sheet of ordinary printed paper, and with such exactness, 
 that it would be impossible, excepting to well-practised eyes, to perceive the least difference between 
 that printed in the usual way, and that which was the result of the autographic process. This mode is 
 very useful when it is desired to unite Oriental characters, which might not be possessed with words, 
 phrases, or lines composed in ordinary typography. In this way have been executed, in the office of 
 the Count M. C. de Lasteyrie, at Paris, (from whose papers on this subject, contained in the Journal des 
 Connaissances Usuelles, and translated by the learned editor of the Franklin Journal , our account of 
 this art is largely indebted,) many pieces, in which the French or the Latin language was intermixed 
 with words or phrases in Chinese or Arabic. In the same way have also been executed typographic 
 maps, in which all the details were lithographic, while the names of places were at first pruduced by 
 typography, and afterwards by autography. This operation is begun by composing and arranging, in- 
 a typographic form, the words, the phrases, or the lines, as they ought to stand. The autographic paper 
 is printed on by this form, and the words in the Oriental languages are afterwards written in the spaces 
 which have been left for them ; the whole is transferred to a stone, which is prepared for the purpose, 
 and from which the impression is taken in the usual manner. The same mode is pursued in making 
 geographical maps. After having printed the names on autographic paper, the other parts of the map, 
 but without the names, are drawn immediately on the stone ; and after having printed the names on 
 white paper, the map drawn upon the stone is printed on this same paper. 
 
 Maps, or line engravings on copper, where the work is not very close, may be multiplied in a similar 
 way. For this purpose the plate of copper is covered over with the autographic ink, diluted to a con- 
 venient consistence. Instead of the autographic ink, a composition is sometimes used, made of one 
 ounce of wax, one ounce of suet, and three ounces of the ink with which the ordinary impressions in 
 lithography are taken. The whole is warmed and mixed well together, and there is a little olive-oil 
 added to the composition, if it is not liquid enough to spread itself over the plate ; the plate ought to 
 be warmed as usual. After having taken the impression in the rolling-press on a sheet of autographic 
 paper, the transfer may be immediately made on to the stone, after having rubbed it with a sponge, 
 dipped in turpentine. It is necessary to give three, four, or even more strokes of the press, increasing 
 the pressure at every successive stroke ; the other processes, which we have already described, are like- 
 wise to be followed. It is well to wait twenty-four hours before preparing the stone, in order that it 
 may be better penetrated by the transferring ink ; it is then gummed and washed, and is ready for use. 
 This process, which has not yet come much into use amongst lithographers, merits the attention of art- 
 ists ; for it affords the means of reproducing and multiplying geographical charts, and some kinds of 
 engravings indefinitely, so that they might be furnished at a quarter of their present actual value ; in 
 fact, all those which are done in lines, or those in w T hich the shadows are boldly executed, are capable 
 of reproducing good impressions by means of autography. The operation becomes extremely difficult 
 when it is necessary to transfer fine line engravings ; the lines of these are so delicate, and so near to 
 each other, that they either do not take well on the stone, or are apt to be crushed and confounded 
 together by the effect of the pressure. Much practice and address are necessary to obtain tolerable 
 impressions; and this part of the art requires improvement. In the office of M. de Lasteyrie, they had 
 succeeded in transferring to stone a small highly finished engraving, which had been printed on common 
 half-sized paper. After having dry-polished a stone very perfectly, it was warmed, rubbed with spirits 
 of turpentine, and then the engraving was applied to it. This had, however, been previously dipped 
 into water, then covered on the reverse side with turpentine, passed again through the water, so as to 
 remove the superfluous turpentine, and then wiped with unsized paper. In this state the engraving, 
 still damp with the turpentine, was applied to the stone and submitted to pressure, when it afforded 
 very good impressions ; the preparation not being applied until it had remained on the stone for twenty- 
 four hours. The difficulties increase, of course, in proportion to the size of the engravings which it is 
 desired to transfer to the stone. Attempts have been made to transfer old engravings ; they have, 
 however, succeeded but imperfectly. It would be rendering an essential service to the att to discover 
 a mode of reproducing old engravings by means of autography ; the undertaking presents difficulties, 
 but from the attempts made, success does not seem improbable. 
 
 Printing from two or more stones with different colored inks. — This is managed by preparing a com- 
 position of two parts of wax, one of soap, and a little vermilion. Melt them in a saucepan, and cast 
 them into sticks ; this must be rubbed up with a little water to the thickness of cream, and applied to 
 the surface of a polished stone. An impression is taken in the common wav from a drawing, and ap- 
 
LOCKS. 
 
 237 
 
 plied to a stone prepared in this manner, and passed through the press, taking care to mark, by means 
 of this impression, two points in the margin corresponding on each of the stones. The artist, haying 
 thus on the second stone an impression from the first drawing to guide him, scrapes away the parts 
 which he wishes to remain white on the finished impression. The stone must now be etched with acid 
 stronger than the common etching water, having one part of acid and twenty of water ; the whole is 
 then washed off with turpentine : this plan is generally used in printing a middle tint from the second 
 stone ; the black impression being given from the first stone, a flat transparent brownish tint is given 
 from the second, and the white lights are where the paper is left untouched. The dots are necessary 
 to regulate the placing of the paper on the corresponding parts of the two stones. 
 
 LOCKS. From the Proceedings of the Institution of Mechanical Engineers. It was conceded about 
 twelve years since in the United States, by all locksmiths, that a lock having a series of tumblers or 
 slides, such as was used at that time in Europe, and more particularly those of Barron and Chubb, was 
 secure against all known means of picking, or of forming a false key by any knowledge that could 1)8 
 obtained through the key-hole. The only point that seemed desirable was to make it secure against the 
 maker, or any party who might have had possession of the key, and from it taken an impression. 
 
 The first step, therefore, was to construct the lock so that the party using it could change its form at 
 pleasure. Mr. Andrews constructed a lock similar to that made by Mr. Chubb, having a series of tum- 
 blers and a detector ; but before placing the lock on the door, the purchaser could arrange the tumblers 
 in any way, so that the combination suited his convenience ; the key being made with a series of mov- 
 able bits, was arranged in a corresponding combination with the tumblers. In order to make a change 
 in the lock without taking it from the door, each tumbler was so constructed that in locking the lock the 
 tumbler could be raised, or drawn out with the bolt. A series of rings was furnished with the key, cor- 
 responding with the thickness of the movable bits of the key ; and any one, or as many more of the bits 
 could be removed from the key, and rings substituted. These bits being removed, and the rings taking 
 their place, the corresponding tumblers would not be raised by the turning of the key, and consequently 
 would be drawn out with the bolt, (becoming, in fact, a portion of the bolt itself.') Therefore, when a bit 
 was removed and a ring substituted, so much of the security of the lock was lost as depended on the 
 tumbler that was not raised ; consequently, a lock having twelve tumblers, being locked with a key with 
 alternate bits and rings, would evidently become a six-tumbler lock ; but should a tumbler that was 
 drawn out with the bolt be raised in the attempt to pick or unlock it, or should any one of the acting 
 tumblers be raised too high, the detector would be thrown, and prevent the withdrawing or unlocking of 
 the bolt. This lock was in great repute in the LTnited States, and was placed on the doors of nearly all 
 the principal banking establishments of the country; a large reward was offered by its maker to any 
 one who could pick it ; and from its great repute it consequently called out many rivals. 
 
 Mr. Newell constructed what he termed his Permutating Lock, which was composed of a series of 
 first and secondary tumblers, the secondary series being operated upon by the first series. Through the 
 secondary series there was passed a screw termed a clamp-screw, having a clamp overlapping the tum- 
 blers on the inside of the lock ; each tumbler in the series having an elongated slot to allow the screw 
 to pass through. On the back side of the lock was a small round key-hole, in which the head of the 
 screw rested, forming, as it were, a receptacle for a small secondary key ; so that when the large key 
 gave the necessary form to the tumblers, the party took the small key and operated on the clamp 
 screw, clamping and holding together the secondary series, retaining them in the relative heights or dis- 
 tances imparted to them by the large key ; the door was then closed, and the bolt projected, and the first 
 series of tumblers fell again to their original position. The objection to this mode of constructing a 
 lock was, that it required the insertion of the small secondary key ; and should the party neglect to re- 
 lease the clamp-screw every time he unlocked the lock, the first series of tumblers would be held up 
 by the secondary series. Consequently, an exact impression of the lengths of the several bits of the 
 key could be obtained through the key-hole while the lock was unlocked. This lock and Mr. Andrews’ 
 were both picked by Mr. Newell, who demonstrated that this lock as well as all others based on the 
 tumbler principle was insecure. 
 
 The first step taken to make a secure lock, was to add a series of complicated wards to the locks ; 
 but it will be readily seen, that what can be reached with a key, could be reached by some other instru- 
 ment ; and, although it required an instrument of a different form, yet the operation was just as certain 
 and fatal to the security of the lock. 
 
 The next step taken, and one which was considered effectual, for a time, was the notching of the 
 abutting parts of the first and secondary series of tumblers, or of the stump face and the ends of the 
 tumblers. So that if a pressure was put upon the bolt, the tumblers could not be successively raised 
 by the picking instrument, being held fast by these “false notches.” This lock baffled the skill of all 
 the country for a time, and was considered perfectly safe, until an ingenious engineer of the name of 
 Pettis picked this lock. 
 
 The Parautoptic Lock was then invented by Mr. Newell, retaining all that was deemed good in the 
 locks previously made, and, at the same time, guarding against all the defects proved by actual experi- 
 ment. 
 
 The annexed figure shows it locked, with the cover and the detector-plate removed, and the auxiliary 
 tumbler in its place ; A A is the bolt ; B B are the first series of movable slides or tumblers ; C, the 
 tumbler springs ; D D the secondary series of tumblers ; and E E the third or intermediate series, which 
 form the connections between the first and secondary series of tumblers ; F F are the separating plates 
 between the first series of tumblers; G, the springs, for lifting the intermediate slides or tumblers to 
 make them follow the first series when they are lifted by the key. On each of the secondary tumblers 
 D D, is a series of notches, corresponding in distance with the difference in the lengths of the movable 
 bits of the key ; and as the- key is turned in the lock to lock it, each bit raises its tumbler, so that some 
 one of these notches presents itself in front of the tooth h, on the dog or lever H H. As the bolt A is 
 projected, it carries with it the secondary tumblers D D, and presses the tooth h into the notches in th« 
 
238 
 
 LOCKS. 
 
 tumblers, withdrawing the tongues d, from between the jaws e e, of the intermediate tumblers E E, and 
 allowing the first and intermediate tumblers to fall to their original position ; whilst the secondary tum- 
 blers D D, are held in the position given to them by the key, by means of the tooth k being pressed 
 into the several notches, as shown. Should an attempt he made to unlock the bolt with any but the true 
 key, the tongues d will abut against the jaws e e, preventing the bolt from being withdrawn; and should 
 an attempt be made to ascertain which tumbler binds and requires to be moved, the secondaiy tumbler 
 D T), that takes the pressure, being behind the iron wall I K, which is fixed completely across the lock, 
 prevents the possibility of its being reached through the key-hole, and the first tumblers B B are quite 
 detached at the time, thereby making it impossible to ascertain the position of the parts in the inner 
 chamber behind the wall IK. The portion II of this wall is fixed to the back plate of the lock, and 
 the portion K K to the cover. 
 
 L is the drill pin on which the keys fits; and MM. is a revolving ring or curtain, which turns round 
 with the key, and prevents the possibility of inspecting the interior of the lock through the key-hole ; 
 and should this ring be turned to bring the opening upward, the detector plate is immediately carried 
 over the key-hole S, by the motion of the pin P upon the auxiliary tumbler 0 0, which is lifted by the 
 revolution of the ring M, thereby effectually closing the opening of the key-hole. As an additional 
 protection, the bolt is held from being unlocked by the stud R bearing against the plate Q ; also the 
 lever T T holds the bolt when locked until it is released by the tail of the detector-plate Q pressing the 
 pin U. Y is a dog, holding the bolt on the upper side when locked, until it is lifted by the tumblers act- 
 ing on the pin W. X X are the separating plates between the intermediate tumblers E E ; Y and Z are 
 the studs for preserving the parallel motion of the different tumblers. 
 
 There are several features in the construction of this lock which are deserving of particular attention. 
 The most novel and extraordinary is, that the lock changes itself to the key ; in whatever form the 
 movable bits on the key are changed, the lock answers to that form, without moving any part of it from 
 the door. 
 
 The party purchasing the lock can change it to suit his convenience. If a 6-tumbler lock, to 720 ; 
 if 7 tumblers, 5,040; if 8, 40,320; if 9, 362;880; if 10, 3,628,800; and if 12, 479,001,600. There- 
 fore it will be perceived that, by changing the numerical position of the bits in the key, the lock can be 
 altered, or in fact alters itself to any number of new locks, equal to the permutation of the number of 
 bits on the key. Two extra bits are supplied with each key, which add very greatly to the number of 
 changes. As the key turns round, each bit raises its tumbler to a point corresponding with its length, 
 imparting to the first and secondary series the exact form of the key. The secondary series of tumblers 
 being carried out with the bolt, and the tooth on the lever or dog being pressed into the several notches 
 on the front face of the secondary series, holds them in the position given them -by the key, while all 
 the other portions of the lock fall again to their original position. 
 
 Should a pressure be put on the bolt to ascertain the obstruction, it will be readily seen that it will be 
 brought to hear on the third or intermediate tumblers. To prevent the possibility of reaching these, 
 there is a wall of metal fixed across the lock, which confines the operator wholly to the key-chamber. 
 By detaching the portion of the tumbler that takes the pressure given to the bolt, from the parts that 
 can be reached through the key-hole, leaving that portion always at liberty, the possibility of ascertain- 
 ing what is wrong is rat off; so that instead, as in the former lock, having only a first and secondary 
 
LOCKS OF CANALS. 
 
 239 
 
 series, Mr. Newell here introduced a third or intermediate series ; thereby throwing the whole security 
 of the lock into a chamber beyond the wall of metal, which is wholly inaccessible, and forming as it 
 were another lock without a key-hole. These are the principal features of security in Mr. Newell’s Pa- 
 rautoptic Lock. 
 
 There is another source of insecurity that has still to be provided against ; when the first tumblers 
 can bo seen through the key-hole, if the under side of them is smoked by inserting any flame, the key 
 will leave a distinct mark upon each tumbler the next time it is used, showing where it began to touch 
 each tumbler in lifting it. This can be seen by inserting a small hinged mirror into the lock through the 
 key-hole, and the exact length of each bit of the key measured, from the centre-pin to the point where 
 it touched the particular tumbler, from which a correct copy of the key can be made. (An electric light 
 from a small portable battery, has been employed for this purpose, to illumine the interior of the lock.) 
 
 The possibility of seeing the tumblers is entirely prevented, by surrounding the inside of the key-hole 
 with a ring or revolving curtain ; and when this curtain is turned, to bring the opening opposite the tum- 
 blers, the key-hole is shut on the outside by the detector tumbler, which tumbler would also detect all 
 attempts at mutilating the interior parts of the lock. 
 
 Should the lock be charged with gunpowder through the key-hole, for the purpose of blowing it from 
 the door, the plug in the back of the key-chamber yields to the force, leaving the lock uninjured, whilst 
 the curtain protects the interior of the lock from injury, thereby effectually preventing all known means 
 of opening or forcing the lock. 
 
 LOCKS OF CANALS. A contrivance by which boats may pass from a lower to a higher level, or 
 the reverse, by the buoyancy of the water. 
 
 The least length that can he allowed between the locks should be such that 12 inches of depth, over and 
 above what a loaded boat will draw, will only lower the water 6 inches without the navigation being 
 interrupted ; and if it be required to draw the contents of each lock from the interval above, the dis- 
 tance for the locks must be so regulated that the quantity of water expended by one should not lower 
 that of the upper interval more than 6 inches at most : thus the distance should be greater in propor- 
 tion to the contents of the chamber of the locks and the width of the canal ; that is to say, when the 
 chambers are large and the canal is narrow, the distance between the locks should be greater. Cham- 
 bers 110 feet in length between the gates, by 17 feet in width, contain 1870 superficial feet; therefore 
 11.843 cubic feet when the fall is 6 feet 4 inches, 15,859 cubic feet when it is 8 feet 6 inches, and 19,635 
 cubic feet when 10 feet 6 inches. If the canal be 48 feet in width, at 3 feet below the ordinary level of 
 the water, the length of the interval should be 446 feet, in order that the expenditure of locks of 6 feet 
 4 inches of fall should not lower the water more than 6 inches ; this length should be 607 feet when the 
 locks are 8 feet 6 inches of fall, and 755 feet when they are 10 feet 6 inches : the distance then between 
 the lower gate of one lock, and the upper gate of the other, should be always about 624 feet for ordi- 
 nary canals. If two locks of 8 feet 6 inches fall were only distant 160 feet, the water drawn from the 
 interval, for the purpose of mounting the boat, would lower it nearly 26 inches, and there would not 
 remain sufficient to keep it afloat; consequently, it would be necessary to draw a lockful from the 
 upper interval, and then a second, to cause it to rise, whilst only one would be required if the locks were 
 at a sufficient distance. 
 
 This example will show the inconvenience of having locks too near each other, which is still further 
 increased when they are contiguous. It frequently happens that several boats arrive together in the 
 same interval, particularly where the bargemen stop or sleep, and that ho water may be lost, the inter- 
 val where they stop should be sufficiently long to admit more than one. If circumstances will not per- 
 mit this, a greater width must be given, that the lockful which the rising boats draw from the interval 
 should not cause the water to lower so considerably as to prevent their floating, or the descending boats 
 force in such a quantity as to make it run over the gates. If the interval has only the ordinary width 
 of 48 feet, it should be 6398 feet in length, so that ten rising boats could stop, if none were descending 
 at the same time, otherwise a part of the water must be drawn from the other intervals to keep them 
 afloat : if there were as many ascending as descending boats, this need not be so great, but this ob- 
 servation proves that in forming a canal it is necessary to have basins at those situations where boats 
 are required to stop any length of time. 
 
 Quantity of water expended by boats in traversing a canal . — It was the opinion of MM. Gabriel and 
 Abeille, that the passage of a boat through the whole length of a canal always cost twice the quantity 
 of water necessary to fill a lock. Belidor thought the same, and it is still the common opinion. M. 
 Thommason has nevertheless maintained that this idea is erroneous, and that when one boat passes 
 several locks one after another, the second boat only expends two locksful in its whole passage ; but 
 when they pass alternately, one up and the other down, that it costs as many locksful as there are locks 
 in the ascension of each boat. He founds this assertion on two statements, one of M. Caligny, the other 
 of M. Regemorte, asserting that the expenditure of the water is the same, whether contiguous or 
 separated ; but this distinction not having been sufficiently examined, a second error has been com- 
 mitted ; but it is undoubted that when locks are contiguous, they often expend more than two locksful ; 
 and it has not been remarked that when the locks are more than 640 feet apart, they often expend only 
 a single lockful for the whole journey. When locks are distant from each other, and the boats pass 
 alternately, one up and the other down, the boat which passes after the first frequently finds in mount- 
 ing all the locks empty, and to fill them it must draw a lockful from each interval and one from the 
 starting point; in descending, as it finds the locks full, it does not draw any from the starting point, 
 consequently it will only expend a single lockful in its whole voyage. 
 
 When the locks are distant from each other, and the boats follow, the second boat will find all the 
 locks full going up, and to ascend it must first empty all, and then fill them with water drawn from the 
 intervals, and the highest from the starting point ; in descending, all the locks will be empty, and the 
 first lock will be filled with water from the starting point, which will serve to fill all the others, so that 
 'h'.s boat will expend two locksful in its journey. 
 
240 
 
 LOCKS OF CANALS. 
 
 When the locks are so near each other that the water of one taken into the interval between the two 
 diminishes the depth of this interval sufficiently to impede the navigation, or when the locks are contig- 
 uous and the boats pass alternately, the second boat in ascending finds all the locks empty, and as it 
 cannot draw water from the intermediate intervals from the contiguity of the locks, all are filled with 
 water from the starting point. Thus in ascending eacli boat expends as many locksful as there are con- 
 tiguous chambers ; in descending, all the locks being full, no water need be drawn from the starting 
 point, consequently in a whole journey as many locksful may be expended as there are contiguous locks 
 in ascending. When the locks are contiguous, and the boats pass each other in succession, the second 
 in ascending will find all the locks full, and to enable it to enter the intervals, it must empty them suc- 
 cessively to fill them with the water from the intervals, except the last, which it fills with water from 
 the starting point; in descending, another lockful is taken from the starting point, so that in this case 
 two locksful are taken from the latter. 
 
 Although the four above cases contain the whole theory of the working of locks, it may be remarked 
 that if two boats meet at the starting point, and two others before or after the starting point, the 
 four will expend five locksful ; if two boats meet at the starting point, and the two following meet there 
 also, the four will only expend four locksful ; if the two last boats that have passed meet before or after 
 the starting point, and the two succeeding meet also before or after the starting point, they then will only 
 expend four locksful, had the first come in an opposite direction to that which had passed previously, 
 and five if it had come in the same direction ; and it has been generally observed, that a boat always 
 takes a lockful from the starting point to ascend, but that it often does not take any to descend on the 
 other side : consequently, when there are no contiguous locks, the boats will only expend a lockful for 
 their whole journey, when they pass the starting point alternately, one going up, the other down : in 
 like manner, where there are contiguous locks, the boats will expend in their journey as many locksful 
 as there are contiguous locks in ascending; when one boat follows another, it will expend two locksful, 
 whether the locks are contiguous or isolated. It must be remarked that the passage of those boats only 
 can be considered relatively to the locks which join the starting point. When the locks are not contig- 
 uous, and their fall is equal, which happens in the lower intervals, it has no influence on the expenditure 
 of water, especially when the boats do not stop any length of time ; in giving 640 feet length to each 
 interval, it is evident, when two boats follow each other, they will never be together in the same inter- 
 val, since, while the second passes the lock, the first will have time to pass the interval and enter the 
 following lock ; thus two boats cannot meet in the smaller intervals, except when one ascends and the 
 other descends, and in this case, as one takes a lockful from the interval, while a second pours one into 
 it, consequently the water does not diminish or increase in it. It must be observed that we can never 
 have above a iockful, more or less, in an interval, unless several boats remain in them together, which 
 should be avoided when they are small ; further, when the contiguous locks are distant from the start- 
 ing point, it often happens that the lockful is not immediately taken ; but when there is no second 
 quantity of water before the contiguous locks, it is always the starting point which furnishes that of the 
 canal above them. 
 
 Form to be given to the chambers of locks. — The most convenient is the parallelogram, a little wider 
 than the boats that require to pass, and sufficiently long to admit of the gates being moved with facility. 
 The chambers of the canal of Languedoc are of an oval form, to give greater strength in resisting the 
 banks contiguous to them ; but as this causes an increase of expense in construction as well as in the 
 quantity of water necessary to fill it, it will be useful to inquire if, in avoiding one inconvenience, a 
 greater is not produced. The oval chambers of the canal of Languedoc contain an area of 3636 feet, 
 while if the side walls were parallel, they would only be 2248 superficial feet. Thus the expenditure 
 of water in the oval chamber exceeds more than a third that of the parallelogram, the proportion being 
 about 5 to 3. The inconvenience is considerably increased by want of water, which frequently occurs 
 Another result of the oval form is, that the passage of the lock is also longer than in the rectangular; in 
 the same proportion the expense of the timber platform is also increased. It is, however, certain that 
 a curved wall is stronger against a pressure of earth than a straight one, and if the cost of masonry 
 requisite to give the same strength to a straight wall is greater, the expense is compensated for by the 
 diminution of the cost of the timber platform, which is two-fifths stronger. It is very essential to pre- 
 vent the filtration of water through the side walls, and the best method to effect this is to place on their 
 thickness a lining of beton, or of brick laid in cement, which will be impervious to water; but as this 
 will destroy the bond, a greater thickness of wall is requisite ; thus there are many circumstances where 
 it might be necessary to give to curved walls as great a thickness as to straight. The thickness of 
 straight walls which support earth should be a third of their height, while those which resist the thrust 
 of water should be one-half; if the walls of the chambers of locks have a thickness relative only to the 
 thrust of the earth, they may give way when the earth is put in motion, which often occurs from a slight 
 filtration behind the wall. Gautliey has a rule for finding the thickness to be given to the wall of a 
 basin intended to support water throughout its whole height, and in the chambers of locks it must be 
 remembered that the thrust of the water against the vertical surface is equal to the product of these 
 surfaces by half the height of the water. Call h the height of the wall, x = its thickness, supposing its 
 length to be 1 metre, the acting power will be 1000 X 4 hi 2 ; supposing the cube metre of water to weigh 
 1000 kilogrammes, and the centre of impression of this thrust being at a third of the height of the wall,- 
 the arm of the lever of the acting power will be equal to \ h. 
 
 The resisting power will be the wall itself=fi vr X 2000, supposing that the cube metre of masonry 
 generally weighs 2000 kilogrammes. The arm of the lever will be half the thickness of the wall ^ x, 
 consequently the momentum of the acting power will be 1000 X | h? X § h, and that of the resisting 
 power 2000' X J h x 2 ; and as in the state of equilibrium these two powers should be equal, we shall 
 have 161 h? ~ 1000 h x 2 , from whence we hove x — -J 0167 h s = 0'41 h ; but as something should always 
 be allowed above the equilibrium, by adding 4-, we shall have x=\h nearly. Hence it is evident that 
 
LOCKS OF CANALS. 
 
 241 
 
 the thickness of a wall intended to support water should be at least equal to half the height of the water 
 which acts against it. 
 
 The length and width of chambers of locks must necessarily be regulated in conformity with the 
 boats used on the canal; these are generally longer and narrower than those on rivers, where the slial 
 lows which occasionally occur require flatter bottoms to be given them. With regard to the length oi 
 the chambers, it should be such as to enable the gates at the lowest ends to open and shut easily; ii 
 the rudder of the boat cannot be unshipped, or occupies any portion of the length of the chamber, then 
 the chambers must be made sufficiently long to prevent them from interfering with the opening of the 
 gate, on which account the most proper rudders for navigable canals are those like broad oars, which 
 can be taken out while passing through the locks. The height of the water in the intervals is regu- 
 lated by the mean height of the waters of the river which communicate with the canals. It is, however, 
 customary to allow the latter a sufficient height of water to receive boats of the same tonnage as those 
 which navigate the river; another advantage in giving an extra depth of water to canals is the greater 
 ease with which the boats can be drawn, the weeds at the bottom causing less inconvenience, and the 
 evaporation being of course less than in a shallower body of water ; in summer also, when the boats can 
 only carry half a load, two loads may be put into one boat, and the transport rendered less expensive. 
 
 The quantity of water expended by locks is found to be in direct proportion to the height of the fall, 
 and the time employed in going through them, and the expense of construction nearly in the same pro- 
 portion ; this is greater as the locks are least elevated, because they are more in number, but the 
 increase is not in proportion to the number. 
 
 Gates of locks are composed of two posts placed vertically, and united by horizontal rails ; the 
 former, being supported throughout their height, are not subject to much wear, although they are of 
 larger scantling than the other timbers of the gate, which is necessary, as they sustain the entire frame- 
 work. The horizontal rails resist the weight, and as that weight is greater where the rails are placed 
 below the level of the water, it would seem natural that their dimensions should vary in proportion to. 
 the weight. To determine these dimensions it must be recollected that the thrust of water against 
 vertical surfaces is equal to the weight of a prism of water having its surfaces as a base, and its height 
 half that of the water. It must next be considered that the rails of the gate are at least 26 inches 
 apart, and 38 inches from centre to centre, so that, on account of the casing of plank in the first 
 instance, 12 inches of height support 26 inches of water, and in the second 38 inches. The weight sup- 
 ported by each rail will be found by multiplying their length, the interval from one to the other, the 
 height of the water above the centre of the rail, and the whole by 62 pounds, the weight of a cube foot 
 of water; the product of these measures will be the number of pounds which the rails ought to support 
 throughout their whole length. 
 
 Timbers from 4 to 5 inches square would be sufficient for small gates, and for larger from 8 feet 6 
 inches to 10 feet 6 inches of fall; with a width of 17 feet between the hanging-posts, the rails would be 
 sufficiently strong if from 7 to 8 inches square, putting six rails in the height. They are generally from 
 9 to 10 inches at least, which is double the strength required ; it is true that the gates are more durable, 
 but the weight is greater, which is sometimes injurious to the collar and the masonry to which it is 
 attached, requiring more reparations than lighter gates. 
 
 The frames or styles of gates should be at least 5 inches in thickness more than the rails, and the joint 
 covered by a fillet, as well as the edge of the planks, which are affixed perpendicularly to the rails, and 
 mortised into the styles, increasing the strength of the rails and the framework by their greater thick- 
 ness. Braces are also introduced between the rails, which aid materially in strengthening them, and by 
 their inclined position transfer the stress to the hanging-post. 
 
 Great gates should always have a line of braces placed diagonally, and making an angle with the 
 lower rail; all the braces above should have the same effect, and consequently the same inclination ; 
 those below resting on the lower rail tend to depress it, and, even when properly framed and pinned 
 into the rails, their inclination towards the hanging-post renders them insufficient to sustain the lower 
 rail ; but they may be made useful by giving them an inclination in a contrary direction, and uniting 
 them by pins to the rails. 
 
 Instead of inclining the braces below the diagonals on the side of the strutt ing-post, a bar of iron is 
 sometimes placed diagonally from the collar to the lower end of the strutting-post, which is an excellent 
 contrivance ; or the planks may be placed diagonally, inclining them from the side of the hanging-post, 
 and crossing them solidly, especially that of the diagonal above the hanging-post, and at the extremity 
 of the lower cross-piece ; or instead of a plank, a piece may be let in in an opposite direction to the cross- 
 pieces, which must not be mortised into, or very little, that it may not be in any way weakened ; this 
 piece united carefully to the lower cross-piece would tie it to the post, and give more solidity to the 
 framework ; the diagonal position of the planks gives them more strength to resist the pressure. There 
 is a little loss of material, but, on the other hand, plank of different kinds may be used after cutting out 
 the knotty or defective portions. 
 
 Gates are opened by means of large timbers fixed above the posts, forming a counterpoise to the gate, 
 and preventing it from grinding the collars and racking the framework ; for this purpose the tail of the 
 balance-beam must be very large. Trees are sometimes used with their butt ends not cut off, to which 
 it is easy to add any additional weight. The hanging-posts often allow much water to be lost, in con- 
 sequence of being obliged to give them sufficient play, and this could scarcely be prevented if the pivot 
 had not a little motion, and the collar fitted exactly ; but the weight of water occasions the gate to 
 unite by pressing it considerably against the hanging-post ; still as this is cut circularly, it only leans 
 against a small portion of its surface, and the water easily passes, notwithstanding the great pressure. 
 To remedy these defects, the posts should be partly cut in a circular form, and partly bevelled ; the 
 latter leaning along its whole length upon the rebate made to receive it, which having a corresponding 
 bevel interrupts any filtration ; the circular part should not touch the masonry, but have sufficient play 
 without affecting the ease of the motion. 
 
 Vol. II — 16 
 
242 
 
 LOCKS OF CANALS. 
 
 The gates of locks of navigable canals are made in a right line, but in great sea-locks they are curved ; 
 Belidor lias demonstrated that these latter are not more solid than the former, but this must only 
 be understood when the curved timbers are made out of straight pieces ; for it is undoubted that, it 
 naturally curved, they are much stronger, and will resist more pressure than straight pieces, especially 
 when resting on their two extremities. The collars embrace the whole heel-post, which being generally 
 12J inches in diameter, produces considerable friction, especially when the balance-beam does not act 
 as a counterpoise ; a large bolt may be placed in the axis of the post, and a smaller collar be substituted 
 to confine it ; but this method can only be applied to chamfered posts ; round posts must have a motion 
 in their collar to lean against the hanging-posts, which could not be effected by an axis ; the collars 
 must be attached to iron anchors strongly bedded into massive masonry. The pivots often get deranged, 
 the posts, as generally made, causing considerable play ; if these were bevelled, the pivots might be 
 fixed and bedded in large stones cramped to those adjoining, or united with anchors to the surrounding 
 masonry. Formerly the pivots were made of copper, but cast-iron is equally efficient; they should be 
 the same size as the ends of the posts, and terminated at the lower end in a spherical form. The other 
 iron work of the gates consists of squares laid on at right angles, which must be very strong ; it is also 
 well to lay on the rails of each sluice a band or two of iron to bolt them securely together. 
 
 Lock-gates measuring 8 feet from the centre of one heel-post to that of the other, are in some canals 
 on a segment of a circle, the chord of which is about the sixth of the span, or a little more : these pro- 
 portions not only allow of the gates being smaller, lighter, and stronger, but also increase the pressure 
 of the heel-post against the hollow quoins, which renders them quite water-tight. Where canals are 
 narrow, the paddles of both the upper and lower gates are usually kept open by an iron pin inserted 
 between the teeth of a rack and pinion which raises them : when the paddle is required to be shut, the 
 pin is withdrawn, and the paddle falls by its own weight. 
 
 Hollow quoins, or upright circular grooves, are formed in the side walls, at the ends of the timber 
 sills, serving as the hinge for the gates ; the upright post that turns within them is called the heel of 
 the gate, and the other the head. The former are retained in their position by a gudgeon or pivot turn- 
 ing in a cup let into the foundation stones for the purpose ; sometimes the pivot is fixed, and the cup 
 revolves upon it. The upper part of the post is retained by an iron ring or strap let into the side wall, 
 and made very secure ; the hollow quoins should be worked with great attention ; they are usually of 
 stone or brick, though cast-iron has been found well suited for the purpose. 
 
 Lock-gates of large dimensions are now usually opened and shut by machinery, and the boom or spar 
 attached to the head-post entirely dispensed with : on many canals a rack-bar of wrought-iron is con- 
 nected with the gates, which are furnished with rollers to run in a groove fitted into the sill, and by 
 working a wheel and pinion, they can be opened and shut at pleasure. We ought not to omit mention 
 of several gates formed like boats, upon the principle of the camel, which rise and fall in deep recesses 
 prepared to receive them as water is pumped out or admitted into them : such boat-gates are sometimes 
 constructed with three parallel keels, which fit into as many grooves in the side walls of the lock ; they 
 are maintained in their position bv admitting the water, and raised by pumping out their contents, after 
 which they are floated away ; for the stop-gates of docks such a contrivance is well adapted, but where 
 the navigation is regular, as on a canal, they are not found to answer, from the time requisite to open 
 and replace them. See Floating Gates of Dry Dock. 
 
 The angle to be given to double lock-gates has long occupied the attention of engineers, but the 
 strongest position may be taken when the angle at the base is 85° 16' nearly, and the sally of the gate 
 is or a trifle more than one-third of the breadth of the lock. 
 
 Valves. — Some lock-gates have their paddles, or valves, made to open and shut by the movement of 
 a lever, the lower end of which being loaded, keeps it always over the aperture in the lower part of the 
 gate : when it is required to be moved, the upper part or handle of the lever is pulled back, and the 
 water forcing its passage through, keeps it open until its weight overcomes the power, and it is balanced 
 back into its original position. 
 
 The crank and pinion working in a toothed-rack are now generally applied to raise the paddle. 
 
 Screws are sometimes used for this purpose, formed of wood, sliding up and down in a rebated frame, 
 fixed in the stone mouth of the conduit or paddle-hole ; the lateral pressure of the water occasions it to 
 adhere closely to the frame, so that it is not only necessary to make it run with the grain of the wood, 
 but also to have considerable power to move it : this is occasionally effected by means of a long iron 
 lever, with an eye at one end that spans the square end of the screw, and allows a sufficient force to 
 be applied to raise the paddle. 
 
 There are several applications of the screw, one of which, as used at the gates of Dunkirk, is very 
 simple, and was for a long time adopted throughout Europe. To overcome the hydrostatic pressure and 
 friction at the mouth of the paddle-hole was a horizontal circular opening, within which was inserted an 
 open cylinder of wood or iron ground to fit it, which could be raised by a lever; the waste water of the 
 canal could then escape over the upper lip of the cylinder and afterwards pass out by the paddle- 
 holes. 
 
 The following figures represent the latest improvements for the valves or sluices of a lock-gate. 
 Fig. 2598 is an elevation. Fig. 2599 a vertical section through G G. Fig. 2600 a horizontal section 
 through A A. 
 
 The object of this improvement is, that while the gate is kept close and tight by the pressure of the 
 water forcing it against its seat, the effort of lifting the gate shall at the same time relieve the segt 
 from the pressure of the water ; and this is effected by means of friction-rollers h h, which immediately, 
 upon the commencement of the lifting of the gate, act as short inclines, thus taking the pressure from 
 the seat, and throwing it upon the friction-rollers or wheels, easing the lifting of the gate. When the 
 gate is closed, the wheels have run off the inclines, and the gate bears against its seat with the pressure 
 slue the head ot water 
 
LOCKS OF CANALS. 
 
 24? 
 
 Iron lock-gates . — The frames of those 
 at the Wet Dock at Montrose are of cast- 
 iron, and entirely covered on both sides 
 ■with wrought-iron boiler-plate : where 
 they are placed the entrance is 55 feet 
 wide in the clear, and the centre of the 
 heel-post is 1 foot within the face of the 
 wall, the distance between their centres 
 being 57 feet : the height of the gates is 
 22 feet 6 inches; they point 10 feet, and 
 their ribs have a curvature on the hollow 
 side of 18 inches. The heel-posts are 21 
 inches in diameter, and in form a little 
 more than a semicircle ; after casting they 
 were turned in a lathe : the thickness of 
 the metal is 14 inch; they each fit into a 
 cast-iron socket, and work on an iron gud- 
 geon 10 inches in diameter, cast on a sole- 
 plate 4 feet 6 inches long, 21 inches wide, 
 and 2 inches thick ; this is dovetailed and 
 riveted firmly into the stone, and after- 
 wards so keyed as to press the heel-posts 
 into the quoins, which are of Kingoodie 
 stone, polished as nearly to the circle as 
 possible, and the stone and iron are in 
 such close contact, that the water is effect- 
 ually prevented from passing throughout 
 any portion of their height. 
 
 The mitre-posts are 184 inches ,in 
 breadth, 14 inch thick : holes are cast in them for the introduction of the iron bars, of which there are 
 eleven to each leaf, 2 inches thick, 16 inches broad at the ends, and 18 in the middle; their cross ends 
 are 18 inches in height and 2 in thickness, with 44 inch screw-bolts to each, which pass through the heel 
 and mitre posts. The clap sill was cast in two pieces for each leaf; it is 8 inches in depth and 1J inch 
 thick ; the height of the sill above the platform is 15 inches. The bottom bar is of oak 12 inches thick, 
 17 inches broad at the ends, and 19 in the middle ; this is bedded on felt to the lowermost cast-iron bar, 
 and securely fixed by 14 inch bolts. The boiler-plates which line both sides of the gates are so ar- 
 ranged that they break joint; for 6 feet in height their thickness is § of an inch — above, only they 
 overlap each other about 24 inches, and were riveted on while hot, that the rivets might completely fill 
 up the holes. The collars of the heel-posts are of wrought-iron, 4 inches by 2 inches, keyed through the 
 
244 
 
 LOCOMOTIVE ENGINE. 
 
 anchors, which are of cast-iron, 3} inches square ; they are dovetailed into the quoins, and run with lead 
 The roller segments or railways are 10 inches in breadth by 1 4 inch, 4 inches in thickness; they arfl 
 sunk into the stone, and securely bolted, and bedded with feltUnd white lead. 
 
 The rollers are of cast-iron and conical, 18 inches in diameter, and 5 inches in thickness, with turned 
 steel axles; the roller-boxes are qf cast-iron II inch thick, moulded to the bevel of the gates, and fast- 
 ened by screw-bolts through the flanks of the horizontal bars : cast-iron covers confine the roller-blocks, 
 which slide up and down withinside the boxes by the action of the top screws ; the roller-bars are oi 
 wrought-iron, 3 inches in diameter, keyed into the blocks at the bottom, each being steadied by three 
 plummer-blocks ; each bar near the top has a coupling, with a square threaded screw, and a brass nut 
 at the top, working in a cast-iron bracket, which bears the whole weight of the outer end of the gate, 
 and is fastened by three screw-bolts through the flanges of the horizontal bars. Each leaf has a sluice, 
 3 feet by 2, the frames of which are 7 inches broad and II inch thick ; the sluice-valves are also II inch 
 thick ; ail the screwed bolts have zinc nuts, tQ prevent the iron from rusting : the sluice-rods are 2 
 inches in diameter, and have a square threaded screw, and a brass nut at the top ; these are worked by 
 a wheel and pinion, and bevelled geer, with a crank-handle, nearly level with the hand-raiL 
 
 The gangway is 42 inches in width, and is supported on cast-iron brackets for each leaf; cast-iron 
 ballusters and a wrought rail is attached to the convex side of the gates, with movable iron stanchions 
 and chains on the other; in each heel-post is a pump with a brass chamber and boxes, 2 1 inches in 
 diameter, with a lead pipe down to the bottom. 
 
 The gates are worked by four double-purchase capstans, and geering with seven 8-inch chains. Tliei? 
 weight is as follows : 
 
 Tons. Cwt. 
 
 Cast-iron work in the gates 64 14 
 
 Wrought-iron 22 154 
 
 Brass 0 5 
 
 Zinc 0 14 
 
 Cast-iron in segments and other fittings 19 0 
 
 107 0 
 
 fit Woolwich the clear opening of the dock-gates is 65 feet, and the weight of each of the two iron 
 g ites is 150 tons. See Gates of Dry Dock, Brooklyn Navy Yard. 
 
 LOCOMOTIVE ENGINE, — 1. A locomotive engine is a steam-engine with two cylinders, formed 
 on the high-pressure principle, without a condenser. The motion of the pistons is caused by the intro- 
 cb’Ction of steam into, and its alternate escape from, the cylinders, which is transmitted by means of con- 
 necting-rods to an axle, furnished with two cranks. 
 
 In boilers of locomotive engines the fire is inclosed in a box having a double casing, with a body of 
 water between: The air enters between the grate-bars. The smoke, flame, and gas, produced by the 
 
 combustion of the fuel pass through, in their way to the chimney, a great number of tubes, which are 
 situated in the cylindric part of the boiler, and extend from the fire-box to the smoke-box, and are sur- 
 rounded by water. These tubes, being of very small diameter, would not pass off the flame and gas 
 with sufficient rapidity if they were not urged by a powerful draught ; this is also rendered necessary 
 to overcome the friction, and the resistance offered by the cold air within them. 
 
 2. Of tlce draught .— The draught is employed to produce a fresh supply of air in the fire-grate, and 
 thereby supply the oxygen necessary for the combustion of the fuel ; it is accomplished by allowing the 
 waste steam to escape at a tolerably high pressure, after it has fulfilled its office in the cylinders. This 
 steam is conveyed from the cylinders to the chimney by a pipe, the upper end of which is contracted 
 for the purpose of confining it, and checking its too rapid escape. If passes off at regular intervals, 
 according to the velocity of the engine, and the force of each puff depends upon the pressure of the 
 steam. The velocity of the steam in the blast-pipe is equal to that due to the initial pressure of the 
 steam, whatever may be the size of the mouth of egress ; but the pressure is at once reduced if the size 
 of the orifice of the blast-pipe be considerable. The great speed with which the steam escapes in the 
 chimney imparts to the air around it a corresponding velocity ; and this air can only be replaced by a 
 current passing from the grate through the fire and tubes. 
 
 We should observe that the contraction of the blast-pipe at its upper extremity, being for the purpose 
 of checking the escape of the steam, and prolonging the time of its engagement, a continued pressure of 
 waste steam is consequently the result, which should be regulated by proper rules or laws, as it ought 
 not to exceed more than is necessary. This pressure is therefore an obstacle to the progress of the 
 engine, in consequence of the draught invariably having the effect of absorbing a part of the power of 
 the engine. Its influence, however, is not felt when moving at a slow velocity, on account of the inter- 
 vals being longer, which gives more time for the steam to escape ; but when the speed is great, the pis- 
 ton-strokes are so rapid that the pressure of steam in the blast-pipe is almost continuous. This pres- 
 sure, consequently, forms a resistance to the motion of the piston. 
 
 3. Of the boiler. — The boiler is the most important part of the engine. There is a fire-box connected 
 with it, the bottom of which supports the grate-bars, and the four sides are formed double, in such a 
 manner as to allow of a space of 24 to 4 inches between them, which is occupied by water ; the fire-box 
 is therefore surrounded by water. It is very important to preserve a sufficient width of water space, 
 otherwise the velocity of the steam at this part of the boiler would prevent the water being replaced 
 with sufficient rapidity, the great heat to which the fire-box is exposed producing steam of very great 
 force the walls, also, from not being sufficiently cooled by the water, would acquire a high degree ol 
 temperature, which would likewise promote the formation of incrustations — the space would conse- 
 quently become filled up, and the casing soon destroyed from the action ot the fire. This serious incon- 
 venience has occurred in boilers where the water-space has been made 2 or 2 4 inches. The top of thg 
 
LOCOMOTIVE ENGINE. 
 
 245 
 
 fire-box is strengthened by pieces of iron, that the force of the steam may not rupture it ; and the whole 
 of the flat portions of the boiler, being unable to resist the pressure of the steam within, are also strongly 
 secured together by bolts to prevent their giving way ; but this is unnecessary with the cylindric portion 
 of the boiler, which resists the pressure without the tendency to rupture. This part is traversed by 100 
 to 150 or more copper tubes, through which the flame and the gas produced from the fuel escape 
 The extremities of these tubes are secured to the plates at each end of the boiler. 
 
 Considering the complication of this casing, one can readily conceive the great play of expansion and 
 contraction produced by the rise and fall of the temperature, and how much the action of such powerful 
 forces tends to wear it out, and to occasion shocks which the several surfaces exposed to the pressure of 
 the steam are unequal to withstand, their form being unfavorable to it; thus, the flat parts become the. 
 soonest deranged. Another circumstance which increases these defects arises from the two extreme 
 parts of the boiler being secured together, partly by the frame and partly by the rails or cross-pieces. 
 The latter are attached to the lining of the fire-box at one end, and to the smoke-box at the other, and 
 are kept cool by the air, and therefore are not subjected to those alternate changes which the body of 
 the boiler undergoes. As long as they remain fixed in their original position, they offer resistance to 
 the play of the other parts ; but when at length they become unfastened, they afford a passage of escape 
 to fhe water of the boiler. We must conclude, from all these forces acting against each other, that 
 locomotive engines possess some degree of elasticity in their several joinings and fastenings, although 
 difficult to be perceived, and which, so far from impeding their progress, actually renders it, after a 
 time, more easy than before. 
 
 The surface of the grate varies. The economy attending great fires arises from the heat being 
 proportionately much more regular than with small ones. It is possible that the rise of temper- 
 ature, produced by the burning of a large body of fuel, exerts an unfavorable influence on the flat 
 sides of the fire-box, the dimensions of which are so considerable. It is probable that an increase 
 in the depth of the grate, combined with the employment of a fuel so little inclined to cake 
 as coke, would be found more advantageous than enlarging its surface, since the passage of the air 
 through a great thickness of coke would raise a large quantity of it to the temperature necessary 
 for its combustion, instead of passing through the fire unconsumed, as it does when filled with 
 too large pieces or laid too thin. This remark applies equally well to the employment of anthracite 
 coal. 
 
 We have only to remark, in addition to our description of the boilers of locomotive engines, that the 
 casing should, at the same time, possess great strength and pliability ; thus, where a very powerful 
 draught is created from a rapid succession oi puffs of high-pressure steam, the heat of the fire gives a 
 high temperature to the several surfaces of the fire-box and tubes, and steam of extraordinary power 
 is generated ; but if the door of the fire-box be opened, a large quantity of cold air is admitted, or if 
 the pumps be held open too long, the air introduces itself into the boiler, and instantly checks the gen- 
 eration of steam ; the pressure is consequently diminished, and at length becomes unequal to a rapid 
 transit of the engine. 
 
 In locomotive, as in stationary engines, the whole of the parts in contact with fuel, flame, and hot air, 
 should be covered with water. The most serious consequences occur if the uncovered portions are 
 allowed to become red-hot, and a quantity of water sufficient to cover them is suddenly let into the 
 boiler ; the production of steam is so rapid, that it becomes too considerable to be wholly carried off by 
 the valves, and an explosion consequently follows. 
 
 Another very essential point for the preservation of boilers is to prevent the formation of deposits. 
 These arise from the calcareous matter disengaged from the water when it is converted into steam, and 
 which is not wholly carried away with it ; but an earthy matter is left, which is constantly increasing in 
 bulk. These incrustations become fixed principally on those parts where the greater portion of the 
 steam is generated ; and, as they acquire thickness, it results that less steam is produced, from their 
 being bad conductors of heat : the metal upon which they are fixed is heated to a much higher degree 
 than the other parts, as it is not cooled by immediate contact with the water. This rise in the tem- 
 perature of the metal increases the action of dilatation, and renders it less able to resist the pressure ; 
 it also has the effect of burning it ; the boiler, therefore, requires to be often cleaned. 
 
 This incrustation is the most powerful destroyer of locomotive engines, and it is of the greatest im- 
 portance to find some means of getting rid of it. 
 
 When the escape of steam from the cylinder is sufficiently strong to cause a powerful draught, then 
 the power of generating steam attains its maximum ; at which instant the bulk of the water in the 
 boiler rises artificially to the height of two or three inches. This is caused by the rapid passage of the 
 particles of steam through the water, which has the effect of increasing its volume. As soon as the 
 throttle is shut, the emission of steam is suspended and the water takes its natural level ; also when 
 cold water is injected into the boiler, which, in proportion as it is introduced, condenses those particles 
 of steam with which it. comes in contact in the mass of heated water, and thus restores the density it 
 had lost. It results that the level of the water remains constantly at the same mark as long as it 
 continues to be fed, and that the introduction of water is only perceivable by tire reduction of the 
 pressure. 
 
 Another fact equally important is the disposition of all locomotive engines, more or less, to carry 
 away a quantity of water into the cylinders with the steam, called primintj. This inconvenience arises 
 from various causes. Among them may be reckoned particles filling the boiler so full that, the water 
 rises up beneath the dome over the steam entrance, and is conveyed into the steam entrance-pipe with 
 the same velocity as the steam, and introducing greasy matters, which, becoming mixed with the water, 
 give it a property analogous to that of milk when submitted to an ebullition, and the quantity of water 
 engaged by the steam in this case is very considerable. 
 
 It may also result from the small diameter of the dome, its want of height, or the space reserved for 
 steam above the surface of the water being too small, or the dome being placed over the fire-box, which 
 
246 
 
 LOCOMOTIVE ENGINE. 
 
 is too often the case ; that is to say, it is placed at that part where the evaporation is greatest, and the 
 particles of water are in the strongest agitation. 
 
 Of the draught. — One of the means employed in regulating the draught consists in placing a disk 
 valve at the extremity of the blast-pipe, which was the invention of Stephenson. This falve is open in 
 the middle, by which it does not offer any obstacle to the passage of the steam ; but it can be made to 
 close the passage whence the flame or gas produced by the fuel issues, when required. This damper is 
 managed by the engine-driver by means of a lever-rod. 
 
 This valve is also useful for another purpose. Thus, when the men extinguish the fire of the engine 
 after it has finished work, the grate being done with and removed, the air enters at this part with great 
 freedom, the heat of the engine maintaining a very strong draught. Now the effect of this passage of 
 cold air is detrimental to the boiler, for the reasons before stated ; therefore, if Stephenson’s damper be 
 fitted in the chimney, and care be taken to shut it close on these occasions, the current of air would be 
 checked, and an excellent effect would result from it. 
 
 Of explosions. — We have few remarks to make on the subject of explosions connected with locomotive 
 engines. Accidents of this kind are wholly attributable to the wilfulness of the engine-driver, or a want 
 of care on his part. His first duty is to notice that the safety-valve does not emit steam exceeding a 
 given pressure. 
 
 It is probably from these explosions being so rare, that the cause of them has been a question up to 
 the present time ; we can give none other than that they are owing to the imprudence of the engine- 
 drivers, from their endeavors to raise the power too high, and thus impeding the escape at the safety- 
 valves. Perhaps this imprudence may be combined with a bad system of closing and bolting the iron 
 plates, and defectiveness in the large interior iron bolts of the front plate. We do not, however, mean 
 to affirm this, but only mention it to our readers, inasmuch as we know that the joinings and 
 arrangement of the plates of some boilers are much less skilfully contrived to resist internal pressure 
 than others. 
 
 One observation will be sufficient to prove to mechanics the uselessness, generally speaking, of in- 
 creasing the pressure, and of tightening the safety-valves. When they thus increase the pressure of the 
 steam in the boiler, the engine simply acquires the power of propelling a heavier train, but it has not 
 any sensible effect upon the speed. They should, therefore, remember that they do not derive any ad- 
 vantage from committing this very great offence. As the steam in the cylinders acts at a less pressure 
 than that in the boiler, of what use is it to increase the latter, when, by opening the regulator a little 
 more, sufficient additional strength is obtained in the cylinders? The most essential thing for the speed 
 is the generation of a large quantity of steam at once, and of the requisite force — sufficient for the dis- 
 charge of a great number of strokes, and not steam generated under a greater pressure than there is any 
 occasion for. 
 
 Distribution. — The steam entrance, or the aperture by which the steam is introduced into the pipes 
 of distribution, is situated in the interior of the boiler, and opens at the upper part of the dome sur- 
 mounting it. The object of the dome is to carry the steam as high as possible, that the water held in 
 suspension may have time to drain from it. The pipe by which the steam is introduced (steam-pipe) is 
 carried along to the extremity of the boiler, and passed through into the smoke-box, where it is divided 
 into two, to supply each of the cylinders. This pipe may be contracted in the interior, by means of an 
 apparatus termed a regulator, which is inserted for the pur pose of regulating the transmission of steam 
 to the cylinders ; this apparatus will also entirely close the passage of the steam-pipe, if required. The 
 steam entrance is placed either at the head of the boiler, above the fire-box, or, otherwise, towards the 
 extremity near the chimney. In the first case, where the pipe traverses the entire length of the boiler, 
 it is attached to the plates at each extremity ; and, in order that it may readily yield to the action oi 
 expansion, it is furnished with a stuffing-box. 
 
 The joints of that portion of the steam-pipe within the boiler should be made with the greatest care, 
 that the water may not gain admittance into the pipe. It is generally formed with a section equal or 
 superior to that of the steam-ports in the passage to the cylinders, and the same as the apertures opened 
 and shut by the regulator. 
 
 Throttle-valves are constructed of various forms ; but that generally employed consists of two separ- 
 ate disks, one being made movable ; and they are cut in such a manner that the open parts of one will 
 either correspond with or cross those of the other, so that the steam passage may be left either open or 
 closed. 
 
 The movable disk is secured to the fixed disk by the pressure of the steam, also by a screw and a 
 spring. The spring is rendered necessary from the steam within the steam-pipe being sometimes of 
 greater pressure than that in the boiler. 
 
 Other forms of throttle have also been employed — and the principle of safety-valves lias been applied 
 in some cases, and in others the principle of cocks — again, that of slides ; those which present the least 
 surface-friction, and in which the apparatus is brought into action upon the least degree of force, are the 
 best, for it is important to counteract the effort required to overcome the pressure of the steam by suita- 
 ble contrivances, as by equilibrating it by a pressure nearly equal ; the friction resulting from the unequal 
 expansion of the several pieces fixed and inclosed witliin each other should also be reduced as much as 
 possible. Throttles formed with cylindric surfaces exposed to the action of friction, possess this incon- 
 venience in the highest degree. There also appears to be some ground for rejecting regulators which 
 require helixes in the interior of the boiler, upon which the pressure of the steam would act. 
 
 Of the cylinders, slide-boxes, and slides. — The steam passes along the breeches-piece leading to the 
 cylinders through the slide-boxes, from whence it is distributed alternately upon each side of the piston. 
 
 The mode of introducing the steam may be readily comprehended : the bottom of each slide-box ia 
 pierced by three holes called ports ; the two extreme ports convey tire steam into the interior of the 
 cylinders at their extremities. A sort of cover, called a slide, is placed over them, which is subjected 
 to an alternating motion when at work, and thus leaves each port alternately uncovered ; and as the 
 
LOCOMOTIVE ENGINE. 
 
 2il 
 
 slide-boxes are kept constantly filled with steam, the latter passes through these ports into the cylin 
 ders at the moment of each being uncovered. It will therefore be perceived that the system of intro 
 ducing steam is very simple. The ejection of the steam from the cylinders remains to be explained 
 every time that steam enters upon one side of the piston, that which has effected the preceding half- 
 stroke escapes at the third port, which is pierced in the bottom of the slide-box, and is not in commu- 
 nication either with the cylinder or the slide-box, where the steam is lodged, but is separated from these 
 and is constantly covered with the movable slide, which covers and uncovers alternately the two othei 
 ports; it is furnished with a pipe at the extremity which leads into the chimney. Now, the movable 
 cover or slide being hollow, it results from its alternate motion that when it uncovers one of the steam- 
 ports and admits steam into the cylinder, it puts the other steam-port in communication with the waste 
 steam-port situated between them, by means of the cavity beneath it ; and the steam admitted into tne 
 cylinder, at the preceding half-stroke of the piston, by the port then uncovered, enters the interior of the 
 slide, forces itself through the waste steam-port, and thence escapes ; therefore the slide-box constantly 
 answers as a passage to conduct the steam into the cylinders, and the cavity within the slide serves 
 only for a passage to convey the steam away from them. The true steam-ports admit steam when 
 they are uncovered, and they alternately convey steam to the waste steam-port when they are 
 covered by the slide ; thus the slide never leaves more than one of the steam-ports uncovered at a 
 time for the passage of the steam, and it covers the other two at the same time, to allow of the waste 
 steam escaping. The force of the steam lodged in the slide-box is therefore employed upon the piston. 
 The waste steam, being put in communication with the atmosphere under the slide, instantly loses its 
 force. The piston is then quickly carried along to the other end by the force of the steam, and the 
 resistance it encounters on the other side is quickly overcome. Now it is the difference between these 
 two forces which causes the engine to perform its several functions ; if these forces were equal, the 
 piston would remain in equilibrio, and without motion. In order that this difference shall be as great 
 as possible, the force of the steam entering the cylinders should not be less than that which exists in the 
 boiler, or the pressure of the steam that passes out of the cylinders greater than the pressure of the 
 atmosphere into which it escapes; but this desideratum is difficult to be attained. The pistons of loco- 
 motive engines being impelled with great velocity, the steam is necessarily carried into the ports of in- 
 troduction with a velocity which is in inverse proportion to the section of the uncovered part (of the 
 port) with the area of the cylinders. This velocity is further affected by the irregularity attending the 
 conversion of a rectilinear motion into a circular one. The latter is accomplished by means of a crank- 
 arm, which follows every movement regularly, and transmits the motion to a rectilinear horizontal rod, 
 the velocity of which is represented by 0293 for the quarter of the revolution which approaches nearest 
 to the vertical, and by O'T 07 for the quarter nearest the horizontal. Thus, the total speed of the piston 
 is composed of a minimum and of a maximum ; the minimum takes place when the crank-arm passes 
 above and below the horizon — the maximum, wdien it performs the quarter of the circle of the passage 
 from one side to the other of the vertical ; in other words, the more the direction of the movement of a 
 crank-arm approaches to a parallel with the rectilinear rod which it works, the greater is the speed 
 transmitted to the rod ; and the more it moves from a parallel, and approaches the rod by a perpen- 
 dicular movement, the slower is the motion imparted to the rod. 
 
 When the engine works at its greatest speed, or at about 38 miles an hour, or 1093 yards per minute, 
 the size of the wheels being 5 feet 3 inches, and their circumference 16 feet 6 inches, the number of 
 strokes of each of the pistons is about 200 per minute, and of their movements 400, the length of eacli 
 being about 1 foot 6 inches, which gives the piston a velocity of 192 yards per minute, or 10 feet per 
 second, instead of about one yard, which is the velocity given to the pistons of stationary engines. The 
 dimensions of the ports are generally l-10th the area of the piston ; the velocity of the steam in the 
 ports would be about 100 feet per second, if they were always entirely open when the piston was 
 moving, which is not the case, the aperture being only fully open during the middle of its course, and 
 at a point where the piston has a speed once and a half as fast as its mean velocity ; the velocity of the 
 steam through the ports would therefore be about 165 feet. Taking the contractions, also, into account, 
 reduces the openings to two-thirds ; we thus find that the steam has a mean velocity of 200 to 250 feet 
 per second at the ports. This velocity, although very considerable, does not, however, produce the 
 injurious effect that was at first imagined. The velocity of the waste steam, in passing into the void, 
 is upwards of 1970 feet per second, and its velocity upon escaping into the atmosphere is about 1400 
 feet, when the absolute pressure of the steam is about two atmospheres. 
 
 This velocity is more than 870 feet for an effective pressure of a quarter of an atmosphere, or an ab- 
 solute pressure of 1 at : 25 ; indeed, the generating pressure of a velocity of escapement equal to 290 
 feet does not exceed l-50th part of the atmosphere alone. 
 
 The resistance arising from the steam-ports is, then, perfectly unaffected at high velocities, but if the 
 latter were even considerable, it would not have a troublesome effect ; indeed, with a speed of 37 miles 
 an hour, the boiler cannot furnish the cylinders with any other than steam of reduced pressure ; there- 
 fore, of what consequence is it that this reduction should be partly caused by the ports, instead of being 
 wholly effected by the regulator ? 
 
 Hut although we have no loss of force arising from the steam-ports, this is not the case with the waste 
 steam-ports. The force which the steam exerts in its escape always diminishes the useful pressure — ■ 
 and it is very considerable, since the velocity is of necessity very great, in order that the cylinders may 
 be instantly cleared. It is, therefore, necessary that the velocity of 250 feet, although sufficient when 
 continued throughout the stroke, should be considerably increased, in order that it may be enabled to 
 free one side of the cylinder instantly. 
 
 In the next place, the steam, after passing out of each of the cylinders, again unites in a pipe, which 
 »s contracted at the upper extremity, and presents another impediment to its passage. This peculiarly 
 formed pipe is employed for the purpose of creating a draught. But the resistance which it produces 
 /s naturally detrimental to the moving-power, which may be accounted for as follows : Suppose that, 
 
248 
 
 LOCOMOTIVE ENGINE. 
 
 with a speed of 39 miles, the cylinders are filled with steam of 3 at : 75, which is successively held and 
 dispersed. In calculating the volume of this steam, with successive stops, we should find that it is 
 nearly double that of the cylinder. Taking the total volume of steam supplied, having the section ol 
 the blast-pipe, (whose conical shape does not present much contraction,) we arrive at this result: that, 
 supposing the escapement to be incessant, the steam would have a mean velocity of 820 feet, corre 
 sponding to a generating pressure of a quarter of an atmosphere. This result shows that this great 
 velocity of escape absorbs a considerable portion of the power of the engine ; and if we remember that, 
 at these same velocities, the motive steam must necessarily diminish the pressure, also that the air op- 
 erates upon and at length overcomes it, we can easily conceive that there are certain limits to the 
 velocity which cannot be exceeded with certain engines, even when running without a load. These 
 limits, which were originally from about 39 to 44 miles an hour, have been increased, with engines made 
 more recently, to nearly 53, or even upwards of 60 miles an hour. 
 
 Eccentrics . — The two pistons are each attached by fixed rods, to guide them in their rectilinear 
 strokes, and by movable rods, called connecting-rods, to an axle furnished with two cranks, set square 
 with each other ; this axle is mounted upon two wheels, which are termed the driving-wheels, and re- 
 ceive a rotative movement direct from the pistons. 
 
 The readiest plan of distributing the steam, at the commencement of the action of the piston, consists 
 in employing the rotative motion of the axle to conduct two eccentrics at the same time with the wheels, 
 which, by their alternating motion, open and close the slides. The eccentrics are placed on the axles 
 of the driving-wheels in such a manner as to disengage the slides from those ports whereby the steam 
 is introduced into the cylinders, and to cover those reserved for its escape, at the commencement of the 
 stroke of the piston ; to accomplish which, each eccentric is mounted upon the axle of the wheels square 
 with the crank of the cylinder, the slide of which it conducts. In order to understand perfectly what 
 then transpires, it is necessary to bear in mind that, when a crank transmits motion to a horizontal rod. 
 it. impresses the rod with a rapid motion when it passes in a vertical, and with a slow one when i' 
 passes in a horizontal direction. 
 
 In accordance with this general law, when two crank-arms are mounted on the same axle, and trans- 
 mit their motion to two rectilinear rods, the motion of each will be different, notwithstanding the cranks 
 are both animated with the same velocity. 
 
 Now, the slow movement occurs precisely at the commencement and at the termination of each half- 
 stroke of the piston, since the crank-arm crosses the horizontal at this particular period. Therefore, il 
 the eccentric be mounted square with the crank, the instant that it crosses in a vertical direction, and 
 transmits the greatest amount of velocity to the slide, the crank wall be in a horizontal position, and the 
 piston will be taking its slowest movement. The steam is introduced and let off uniformly every time 
 the crank-arm is in a horizontal’ position — that is to say, every time the piston has finished one stroke 
 and is commencing another — and it is performed with great precision, depending upon the uniform ac- 
 tion of the slide. It may be further observed, in the case of one crank being placed on the same axle 
 with another, when one is passing from one side to the other, in making a semi-revolution, the other is 
 passing from the top to the bottom ; or if each of these cranks transmits a rectilinear motion to a rod, 
 the rod conducted by the first crank conveys a certain motion in one direction, and that conducted by 
 the other conveys the same amount of motion, but distributed in the opposite direction. The results of 
 this uniform principle in the construction of locomotive engines are as follow : At the instant one of the 
 cranks is in a horizontal position, and the piston at the commencement of its stroke, during the first half 
 (of this stroke) the slide moved by the eccentric, which is in a vertical position, conveys a motion 
 which has the effect of uncovering one of the ports, and by the time the eccentric arrives at the horizon 
 it becomes wholly uncovered. Jn the second half of the course of the crank, the slide returns to its 
 original position, and the port becomes again covered. The slide is, therefore, always ready to uncover 
 the opposite port at the commencement of the following stroke. 
 
 It further results, when the crank is horizontal, that the two steam-ports are shut, the eccentric being 
 then in a vertical position. 
 
 Such is the principle of the distribution of steam. We shall not enter into the particulars of the 
 several plans for effecting it at present, but their details, which do not differ essentially from each other, 
 will be found in their proper place. The return motions, from the eccentrics to the slides, are con- 
 structed of slight rods, and are therefore readily shifted ; yet, as the slides are drawn backwards and 
 forwards under the pressure of the steam they are subjected to considerable friction, the rods are liable 
 to be strained, and frequently become deranged by the eccentrics, also from the play of the points of 
 the levers, and the several turning-joints being so very elastic. These circumstances of derangement 
 have an important influence, by retarding the slide slightly, which has a powerful effect upon the regu- 
 larity of the distribution ; and since the course of the eccentric is similar to that of the slide, the deten- 
 tion of the action and the loss of speed occurring in the return movement from the above causes, show 
 the necessity of the engine-nfan devoting the greatest attention to this point, and avoiding the evil as 
 much as possible. The distribution of steam may be suspended whenever required, by means of hand- 
 geer and reversing-handles, which detach the rods of the eccentrics from the levers which conduct the 
 slides ; the same levers are also employed to reverse the movement of the slides at the time of running, 
 and in such a manner as to render it opposite to the direction the engine is running in. 
 
 This reversing the distribution of the steam is employed to stop the engine where other means are 
 found insufficient, in which case the steam-ports on that side where the piston is returning become in- 
 stantly uncovered, and the steam fills the whole cylinder, and thus opposes the progress of the piston ; 
 the latter returns the steam again to the boiler if it should not be arrested. At the same instant the 
 waste steam-port is covered by the slide, and consequently put in communication with the air, which 
 enters by the blast-pipe and fills the cylinders, being drawn in by the action of the piston. Tims, the 
 advance of the engine against the steam has the effect of conveying the air into the boiler, and the 
 safety-valves consequently emit steam mixed with air. 
 
LOCOMOTIVE ENGINE. 
 
 24C 
 
 Of the feeding of the boiler . — Having described the means of generating steam, and of distributing 
 it in the cylinders, we shall now consider those for renewing the water in the boiler in sufficient quantity, 
 as it becomes absorbed by the work of the engine. There are two pumps employed in effecting this, 
 which arc on the lift-and-force principle ; the pistons consist of plungers, similar to those employed in 
 ordinary stationary engines. They transmit the water from the tender to the boiler. One of these 
 pumps can deliver a volume of water in the course of about twenty minutes sufficient to supply the 
 boiler for one hour’s run. The quantity of water furnished by the pumps may be properly regulated, 
 and the delivery of the same rendered continuous, but the latter is only accomplished in new engines , 
 the boilers of the other engines are sure to be momentarily chilled, either in the operation of feeding 
 with water, or in replenishing the fire with fuel ; but the fires of new engines are not so liable 
 to this. 
 
 Of the machinery and its disposal. We shall conclude our general observations on locomotive 
 engines by referring to the disposal of the machinery connected with them. The power of the engine 
 originates in the cylinders, the force produced within them proceeding through the smoke-box in which 
 they are inclosed. This force or power acts in two ways, dependent upon the steam being on one side 
 or the other of the pistons, and imparts to the rods an effort of traction or of pressure accordingly. The 
 whole of this force is exerted upon the cranked axle, wherefore it becomes highly necessary that this 
 axle should be attached to the cylinder-box by very strong framing ; the boiler is for this purpose placed 
 on a frame, with which it is connected by stays secured by strong bolts. There are many engines 
 which, after a few months’ work, manifest a sensible play, to an experienced eye, between the cylinder- 
 box and the supports of connection between the boiler and the frame, from this reason. The carriages, 
 or grease-boxes, which receive the gudgeons at the extremity of the axles, and thus support the entire 
 weight of the engines, are situated beneath this frame, the gudgeons turning freely in them. 
 
 If these carriages were the only points of resistance to the cylinders, it is probable that not only the 
 supports of the boiler on the frame would soon give way, but the axletree, being only secured at its 
 extremities, would also be subjected to these vibrations, and the greater part of it so powerfully forced 
 in each direction, horizontally, by the cranks, that they would be soon broken. It is to obviate this that 
 the cylinder-box is attached to the cranked axle by four, or at least three iron rails. These rails are 
 strongly fastened to the cylinder-box, and each carries a copper collar, in which the cranked axle is in- 
 closed. This collar is capable of moving in a vertical direction, whereby it is enabled to accommodate 
 itself to the play of the springs and countersprings, which frequently have the effect of separating the 
 axletree from the boiler ; but the collar is always secured horizontally, being that in which the cranked 
 axle offers the greatest resistance, by means of suspended wedges, which operate similarly to keys, and 
 tighten the carriages against the axletree. The cranked axle is secured in this manner at five or six 
 places respectively, and further attached to the cylinder-box. The attention of the engine-driver should 
 be directed to these rails of attachment, and he should constantly notice that they fulfil their office 
 properly ; and in furtherance of which he should tighten them, by heightening the wedges as the car- 
 riage of the axletree becomes worn. 
 
 The three principal rails or cross-pieces which we have noticed, are attached just at their extremities, 
 next the axletree, to lugs fastened to the fire-box. It is of consequence that these joints should not be 
 made too stiff, and that a little play be allowed for their extension in cooling, for the reasons before 
 stated, viz., that these rails are not subjected to the same degree of elongation from the effects of ex- 
 pansion as the body of the boiler ; and, upon this occurring, the boiler is forced upon the rails, and the 
 joints connecting them with the fire-box consequently become deranged, and give passage to the water 
 situated within the double casing surrounding the fire-box. 
 
 We have now to observe, that the necessity of reducing the weight of locomotive engines has led to 
 the almost exclusive employment of iron in their construction, from which it results that the whole of 
 the several pieces in friction against each other, from the effects of rotative or rectilinear movement and 
 the sliding of one surface upon another, are proportionately weaker than those of ordinary stationary 
 engines, the castings included, viz., the axeltrees, the beams, the connecting-rods, the guides, the eccen- 
 trics, &c., and formed of smaller proportions. Now, there is a very important fact connected with 
 engines, viz., the circumstance that the friction does not depend solely on the pressure, but on the de- 
 gree of fitness of the metal to support the pressure without alteration. Thus when the state of the 
 carriages becomes altered, the friction acquires immense influence; the bodies become heated and 
 reduced from the filing, arising from the grip they have of each other ; they also sometimes become 
 melted. The rubbing surfaces are therefore kept constantly oiled, to prevent any alteration taking 
 place ; and this is more especially necessary with locomotive engines, as these surfaces are generally 
 reduced almost to the minimum limits commensurate with the amount of pressure which they have to 
 support. The least negligence on this point is consequently attended with serious consequences ; the 
 first, from its increasing the resistance of the engine considerably, and qften stopping its progress ; 
 secondly, from its increasing the wear of the carriages ; and, thirdly, from its causing the rupture of the 
 pieces in consequence of their becoming heated, and the strains to which they are subjected. If the 
 carriages become heated in the smallest degree, they are subjected to great pressure, and the relative 
 hardness of the metals in contact is instantly changed, and the adherence between their surfaces in- 
 creased, so that they become full of holes and impaired, and oil will never restore the delicate finish 
 which is thus destroyed. 
 
 A constant attention to the greasing, therefore, constitutes one of the surest means of preservation, 
 and of insuring good work in the. locomotive. Another circumstance no less necessary, is the mainte- 
 aance of the whole of the several pieces in a condition as near their original form and mounting as pos- 
 sible. An engine is composed of so many pieces, and is subjected to such strong vibrations under the 
 influence oi shocks, and from the sudden and incessant strains that it is subjected to, that it yields in a 
 certain degree at its joinings. The engine-driver should direct his attention to the prevention of this 
 movement, and he should not allow of any more play in the carriages than is necessary ; lie should re- 
 
1150 
 
 LOCOMOTIVE ENGINE. 
 
 place those pieces which become worn, and tighten those mountings as they become loosened. Ti e 
 several joinings are, moreover, disposed in such a manner as to counteract the difficulties connected with 
 • them, and exhibited with all the pieces thrown in friction with each other. 
 
 Respecting the frames of locomotive engines, we may remark, that the plan of arrangement has been 
 a subject of much controversy, whether they should be placed on the outside or on the inside of the 
 wheels. If a perfectly rigid shaft were urged in a rotative direction by a rectilinear force, it would 
 revolve with a degree of firmness proportionate to the distance its carriages were placed apart. If a 
 cranked axle be supported by carriages situated near its centre, and impelled by forces acting ir. 
 eontrary directions, as those transmitted to it from the cylinders, it would cease to be perpendicular to 
 the movement of the pistons, upon the carriages becoming the least worn, and would form an angle 
 proportionably large, accordingly as the carriages were placed near the centre. The flanges surround- 
 ing the wheels would therefore knock against the rails, and the engine undergo violent lateral move- 
 ments from its direct course, which would be dangerous, on account of the gre&t velocity. A like effect 
 occurs when the cranks are placed at the extremities of the axle, instead of near the middle of it, as in 
 the case of engines having the cylinders placed on the outside. The wear of the carriages, also, has 
 the effect of increasing the force of the lateral movements considerably. 
 
 Of locomotives employed in conveying freight. — It is customary, in the conveyance of freight, to 
 employ engines with their driving-wheels coupled to the fore ones, which is effected by connecting- 
 rods ; in which case the fore-wheels are of equal diameter with the driving-wheels. This coupling 
 possesses no other advantage than that of increasing the power of adhesion, by allowing the fore- 
 wheels to partake of the weight carried by the others. 
 
 Of the tender. — A sort of wagon is attached at the extremity of a locomotive engine when in 
 motion, which is called a tender, and which is generally mounted on four wheels, and sometimes on 
 six. It contains water and fuel sufficient to feed the boiler and grate during a run of about twenty- 
 five miles as a maximum, and about fifteen miles as a minimum. In order to supply trips exceeding 
 these limits, reservoirs of water and depots of fuel are arranged at convenient distances on the line, 
 which enables them to extend their run to distances which are only limited by the strength of the en- 
 gines. 
 
 The tender is joined to the engine which it accompanies by a bolt, which is adjusted to fit into a 
 staple. This bolt should be capable of resisting the entire power of the engine. The reservoir of 
 water communicates with the engine by the two pipes of the feed-pumps ; the connection of the barrels 
 of the pumps is made by means of a flexible pipe, denominated hosing, whose nature is such that it 
 can readily yield to all lateral and vertical movements of both engine and tender ; the movements are 
 inevitable, for reasons before stated, from the little stability of the railway, the great velocity of the 
 engines, &c. The bolt admits of every movement, except that of lengthening. 
 
 Tenders of good construction should present an appearance of lightness combined with solidity ; the 
 joints of the iron plates composing the reservoir of water should be well stopped ; the cocks of the sup- 
 ply-pipes to the pumps also require to be made perfectly water-tight, which is a condition they do not 
 always fulfil. The fuel in the tender is placed upon a level with that in the fire-grate. The wheels 
 are wedged on the axletrees similar to those attached to the engine, and the weight of the tender is 
 suspended on springs, to remedy the abrupt motion of the water. There is a hook at the back of the 
 tender, which is attached to a powerful spring, to neutralize the effects of concussion, and for the pur- 
 poses of traction, and it converts all shocks occasioned by the jerking of the engines, which are some- 
 times very abrupt, into pressures more or less strong accordingly. 
 
 Explanation of the principles which govern the power of locomotive engines. — The power of a loco- 
 motive engine is not to be estimated alone by the pressure of the steam in the boiler, and the diameter 
 and length of stroke of the piston. In passing between the boiler and the cylinder, the elastic force of 
 the steam is diminished, before it reaches the cylinder, by the smallness of the apertures of the steam- 
 pipes, through which it has to pass. This difference is, likewise, more frequently produced by the 
 evaporating power of the engine not being capable of keeping up a supply of steam to the cylinders, 
 of an elasticity equal to that in the boiler ; and, therefore, the pressure upon the piston is less than 
 that against the steam-valve of the boiler; and this diminution of the elasticity of the steam, in the 
 cylinders, as compared with that in the boiler, will, in many cases, be in the ratio of the increase of 
 velocity of the engine. Thus, suppose an engine capable of evaporating a certain quantity of water 
 per hour, or converting it into a certain bulk or quantity of steam, of the elasticity indicated by the 
 valve on the boiler ; if this production of steam is sufficient to supply as many cylinders full of steam, 
 of the density of that in the boiler, as shall be equal to the number of strokes per minute of the piston, 
 required to produce the given velocity ; then, the elasticity of the steam in the cylinder will be the 
 same as that in the boiler, except that which is required to force the steam through the steam passages 
 with the requisite velocity ; and, consequently, the pressure on the piston will be nearly the same as 
 that in the boiler. But, if the velocity of the engine is such, that the number of cylinders full of steam- 
 required is greater than the evaporation of the boiler can supply, at the elasticity marked by the steam 
 valve, then the elasticity in the cylinders is correspondingly diminished. Thus, suppose an engine 
 capable of evaporating 50 cubic feet of water into steam per hour, and that the pressure on the steam 
 valve is 50 pounds per square inch ; this will supply a given number of cylinders full of steam of that 
 elasticity. Suppose the resistance to the motion of the piston be equal to this pressure of the steam, 
 or equai to the elasticity of 50 pounds per square inch of the surface of the piston; then the engine 
 will travel at that rate, which the evaporating power of the engine will supply it with the requisite 
 number of cylinders full of steam. But, suppose, the resistance upon the piston increased by a change 
 in the gradients of the railway, then the velocity of the engine will be diminished, until the evapora- 
 ting power raises the elasticity of the steam in the boiler, so as to counterbalance the increased resist- 
 ance of the piston, and the engine will consequently move more slowly. On the contrary, if the 
 resistance be diminished by a change of the gradients of the railway, then steam of a less density will 
 
LOCOMOTIVE ENGINE. 
 
 2ol 
 
 be required, and, consequently, a greater number of cylinders full will be furnished by the boiler, and 
 the velocity of the engine will be increased. 
 
 We see, therefore, that the only correct expression of power of these engines, is the evaporating 
 power of the boiler, and that the velocity with which the engine will move, will depend entirely upon 
 the quantity of water it can convert into steam in a given time ; or the number of cylinders full of 
 steam, of a given elasticity, which the boiler can produce in a given time. Having found, therefore, 
 by experiment, the quantity of water which an engine, of given dimensions, can evaporate per hour, 
 we then find the power which that engine is capable of exerting upon the piston, and the velocity, or 
 number of strokes per minute, which that evaporation will produce, with a given load. The volume 
 of steam which a cubic foot of water will produce, depends upon the elasticity ; this has been ascer- 
 tained by various experimentalists, and the following Table will show the result. The third column is 
 the result of Mr. Pambour's later investigations : 
 
 Relative volume of the steam generated under different pressures, calculated by the proposed formula. 
 
 Total pressure 
 of the steam, in 
 pounds per square 
 inch. 
 
 Volume of the 
 steam, calculated 
 by the ordinary 
 formulae. 
 
 Volume calcu- 
 lated by the pro- 
 posed formula for 
 high-pressure 
 non-conducting 
 engines. 
 
 Total pressure 
 of the steam, in 
 pounds per square 
 inch. 
 
 Volume of the 
 steam, calculated 
 by the ordinary 
 formulas. 
 
 Volume calcu- 
 lated by the pro- 
 posed formula for 
 high-pressure 
 non-condensing 
 engines. 
 
 15 
 
 1669 
 
 “ 
 
 65 
 
 434 
 
 436 
 
 ‘20 
 
 1280 
 
 1243 
 
 70 
 
 406 
 
 406 
 
 25 
 
 1042 
 
 1031 
 
 75 
 
 381 
 
 381 
 
 30 
 
 882 
 
 881 
 
 80 
 
 359 
 
 358 
 
 35 
 
 765 
 
 768 
 
 85 
 
 340 
 
 338 
 
 40 
 
 677 
 
 682 
 
 90 
 
 323 
 
 320 
 
 45 
 
 608 
 
 613 
 
 105 
 
 281 
 
 276 
 
 50 
 
 552 
 
 556 
 
 120 
 
 24? 
 
 243 
 
 55 
 
 506 
 
 509 
 
 135 
 
 224 
 
 217 
 
 60 
 
 467 
 
 470 
 
 150 
 
 203 
 
 196 
 
 We propose now to give the formulae for calculating the powers and proportions of locomotive en- 
 gines, commencing with the values, as ascertained, of the various causes of retardation in the movement 
 of a train on a railroad drawn by a locomotive engine ; and, combining these values, exhibit a general 
 formula; for all cases of the movement of a locomotive, and under all circumstances. 
 
 1. Resistance to motion caused by the atmosphere . — The resistance against a body moving in an indef- 
 inite fluid, at rest, is less than the resistance experienced by the same body placed at rest in an indefinite 
 fluid moving against it, which seems to denote that a fluid in motion separates itself less easily than a 
 fluid at rest. The second is, that a thin plate meets with a greater resistance from the air than a pris- 
 matic body presenting in front the same surface, and that the resistance diminishes according as the 
 prism is longer. This circumstance is occasioned thus : The air having glided over the edges of a thin 
 body, rushes immediately behind it with great rapidity, and carrying in its motion the portion of fluid 
 which we have mentioned above, produces a relative vacuum behind the opposed surface. But if the 
 moving body be a lengthened prism, the air in passing along its sides loses a certain portion of its ac- 
 quired velocity, and, consequently, on reaching the hind-face of the prism, extends itself behind it with a 
 force more and more moderated; whence results that it produces there a partial vacuum, or non- 
 pressure, less considerable than in the case of a simple surface. And as we have seen that the definitive 
 resistance against a moving body is the difference between the pressure of the air in front and the par- 
 tial vacuum created behind, it follows that longer bodies definitively suffer from the air a less resistance 
 than bodies of inconsiderable thickness. 
 
 The experiments of M. Thibault have confirmed those of Borda, on the proportionality of the resist- 
 ance of the air to the square of the velocity, within the limits of velocity that we have to consider. 
 They have, moreover, demonstrated that if two square surfaces be placed so that one shall precisely 
 screen the other, and at a distance apart equal to one of their sides, the resistance against the screened 
 surface will be 7-10ths of the resistance suffered by the surface in front. It consequently results that, 
 when two surfaces are separated by a considerable space relatively to their extent, the resistance of the 
 air against the second is to be estimated nearly as if it were isolated in the air ; but if, on the contrary, 
 the two surfaces are very near each other, relatively to their extent, there is room to think that the 
 screened surface may be almost entirely protected against the effect of the air, since a space equal to 
 one side of the surface would be requisite for the air to exert against it a resistance equal to two-thirds 
 of the resistance against an isolated surface. 
 
 Uniting the results, and limiting ourselves to the case of a body moving in the air at rest, we have, 
 to determine the resistance of the air, the following formulas, in which X represents the front surface of 
 a body traversing the air in a direction perpendicular to that surface, V the velocity of the motion, e a 
 coefficient variable with the length of the body, and, lastly, Q the definitive resistance produced by the 
 air against the body : 
 
 Q ^-0011896 t x V 2 . Eesistance of the air expressed in English pounds, the surface X being expressed 
 in square feet, and the velocity Y in English feet per second. 
 
 And in applying these formuke it will be necessary, according to the case, to give t ) the letter s the 
 following values. 
 
252 
 
 LOCOMOTIVE ENGINES. 
 
 For a thin surface t = 143 
 
 For a cube t = 1-17 
 
 For a prism of a length equal to three times the side of its front surface t = 110 
 
 Of the resistance of the air against the wagons, isolated or united in trains. — From what we have just 
 seen, it will be easy to estimate the resistance of the air against a prismatic body in motion, when its 
 front surface and dimension in length are known. But as a wagon does not present a regular prismatic 
 form, it becomes necessary first to consider how we may find what surface it really offers to the shock 
 of the air. 
 
 The front surface of a wagon may be directly measured ; it consists of two distinct parts, the surface 
 of the load, and that of the wagon itself. The former of these surfaces necessarily varies according to 
 the nature of the goods which form the load ; and the surface of the wagon, properly so called, includes 
 the spokes of the wheels, the axletrees, axle-boxes, springs, and hind-wheels of the wagon. 
 
 We obtain, as the result of sufficiently extended experiments for separate wagons, the value of t in 
 the preceding formulae to be = 1T5. 
 
 As to the trains of several wagons, we see that for the resistance of the wheels, an addition must be 
 made to the transverse section of the train ; but as the wagons composing the same train, though very 
 near each other, are not however in contact, it is necessary further to seek upon what extent of surface 
 these wagons, thus united, still suffer the resistance of the air during their motion. 
 
 From the result of a number of experiments undertaken to determine this resistance, it was found 
 that in order to estimate the effects of the resistance of the air against the progression of a train, to take 
 as resisting surface that of the wagon of greatest section, augmented by 10 square feet per intermediary 
 wagon, and by 6 square feet for the first wagon, including of course in this number the engine itself and 
 its tender. 
 
 On railways of about 5 feet width of way, the surface of the highest wagon may, at a medium, be 
 reckoned at 70 to 74 square feet; we may then esteem, in general, the resisting surface of a train of 
 wagons at 70 square feet, plus as many times 10 feet as there are carriages in the train, including the 
 engine and its tender. 
 
 If the road has a wider way, or if the carriages offer a surface different from that we have just indi- 
 cated, the carriage of greatest section must be measured, and that measure used instead of the number 
 70. If the wheels of the wagon are more than three feet in diameter, there will likewise be an addi- 
 tion to make to take account of the greater surface which they expose to the shock of the air during 
 the motion. This addition would be about 3 square feet per wagon, for wheels of 5 feet in diameter 
 instead of 3. Finally, if the interval between the wagons, instead of being as it is at a medium on or- 
 dinary railways, considering the different kinds of carriages and the inequalities of their loading, were 
 augmented by any important quantity, there might also be some addition to make for the effect of the 
 air against the loads of the successive wagons ; but as our determination in this respect gave something 
 less than one square foot per wagon, and as the interval between the wagons could not be augmented 
 by any thing considerable without being liable to inconveniences in practice, we deem that one square 
 foot per wagon may comprehend nearly all cases. 
 
 • When the effective surface presented to the shock of the air shall be known by the preceding calcu- 
 lation, it must be substituted for the letter 2 in the formulae given above, putting at the same time 
 for t its value suitably to the length of the prism formed by the train of wagons. According to the va- 
 riation of £ observed by Dubuat for prisms of divers proportions, it will be found that in the case of a 
 train of 5 wagons, we must make £ = 1'07, and that the case of a train of 25 wagons would require 
 £ = T04. In order then not to have to return continually upon these considerations we will take as a 
 medium t = 1-05, which is suitable to a train of 15 wagons, and expressing at the same time, in the 
 formula given above, the velocity in miles per hour, we shall have, in fine, to express the resistance of 
 the air against a train of wagons in motion, the following formula : 
 
 Q = -002687 j»’. Resistance of the air, in pounds, the effective surface, of the train or the quantity 
 S being expressed in square feet, and the velocity of the motion in miles per hour. 
 
 Table of the resistance of the air against the trains. — To dispense with all calculation relative to the 
 resistance of the air, we here subjoin a table showing its intensity for all velocities from 5 to 50 miles 
 per hour, and for surfaces of from 10 to 100 square feet. Were it required to perform the calculation 
 for a velocity not contained in the table, it would evidently suffice to seek the resistance corresponding 
 to half that velocity and to multiply the resistance found by 4; or, on the contrary, to seek the resist- 
 ance corresponding to the double of the given velocity, and to take a quarter of the result. So the 
 resistance of the air against a surface of 100 square feet, at the velocity of 50 miles per hour, is equal 
 to four times the resistance of the air against the same surface at the velocity of 25 miles per hour. 
 As to surfaces greater than 100 square feet, they must be decomposed into surfaces less than 100 feet, 
 and then the table will still give the results required ; for the resistance against a surface of 120 square 
 feet is evidently nothing more than the sum of the resistances against one surface of 100 square feet and 
 one of 20 square feet. 
 
 By means of the table in question will be obtained, without calculation, the resistance of the air ex- 
 pressed in pounds, for any velocity of the moving body ; but it is to be observed that the table supposes 
 the atmosphere at perfect rest. If, then, there be a wind of some intensity favorable to the motion, or 
 contrary to it, account must be taken thereof. In order to effect this, it will suffice to observe that if 
 the wind is favorable, the body will move through the air only with a velocity equal to the difference 
 between its own absolute velocity and that of the wind ; and that if on the contrary the wind is opjiosed 
 to the motion, the effective velocity of the body through the air will be equal to the sum of its own ve- 
 locity augmented by that of the wind. In this case, then, the velocity of the wind must first be meas- 
 ured, by abandoning a light body to its action, and noting the time in which it traverses a space pre- 
 viously measured on the ground; or else an anemometer may be used for the purpose. Then tha 
 
LOCOMOTIVE ENGINE. 
 
 
 velocity of the wind must be subtracted from that of the train in motion or added to it, according to the 
 ease ; and that difference or that sum is the velocity to be sought in the table, or substituted in the 
 formula, to obtain the corresponding resistance against the whole train. 
 
 If the wind, instead of being precisely contrary or favorable to the motion, should exert its action in 
 an oblique direction, it would tend to displace all the wagons laterally ; and consequently, from the 
 conical form of the wheels, all those on the further side from the wind would turn on a larger diameter 
 than those on the side towards the wind. The resistance produced will therefore be the same as that 
 which would take place on a curve on which the effect of the centrifugal force were not corrected, and 
 tliat resistance would necessarily be very considerable. 
 
 Practical Table of the resistance of the air against the trains. 
 
 Velocity of mo- 
 tion in miles per 
 hour. 
 
 Resistance of the 
 air in pounds per 
 square foot of 
 surface. 
 
 Resistance of the air in pounds; the effective surface of the train, 
 in square feet, being: 
 
 20 
 
 30 
 
 40 
 
 50 
 
 60 
 
 70 
 
 80 
 
 90 
 
 100 
 
 Miles. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 5 
 
 •07 
 
 i 
 
 2 
 
 i, 
 
 3 
 
 4 
 
 5 
 
 5 
 
 6 
 
 7 
 
 6 
 
 TO 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 7 
 
 T3 
 
 3 
 
 4 
 
 5 
 
 7 
 
 8 
 
 9 
 
 11 
 
 12 
 
 13 
 
 8 
 
 •17 
 
 3 
 
 5 
 
 7 
 
 9 
 
 10 
 
 12 
 
 14 
 
 15 
 
 17 
 
 9 
 
 *22 
 
 4 
 
 7 
 
 9 
 
 11 
 
 13 
 
 15 
 
 17 
 
 20 
 
 22 
 
 10 
 
 •27 
 
 5 
 
 8 
 
 11 
 
 13 
 
 16 
 
 19 
 
 22 
 
 24 
 
 27 
 
 11 
 
 •33 
 
 7 
 
 10 
 
 13 
 
 16 
 
 20 
 
 23 
 
 26 
 
 29 
 
 33 
 
 12 
 
 •39 
 
 8 
 
 12 
 
 15 
 
 19 
 
 23 
 
 27 
 
 31 
 
 35 
 
 39 
 
 13 
 
 *45 
 
 9 
 
 14 
 
 18 
 
 23 
 
 27 
 
 32 
 
 36 
 
 41 
 
 45 
 
 14 
 
 •53 
 
 11 
 
 16 
 
 21 
 
 26 
 
 32 
 
 37 
 
 42 
 
 47 
 
 53 
 
 15 
 
 ■60 
 
 12 
 
 18 
 
 24 
 
 30 
 
 36 
 
 42 
 
 48 
 
 54 
 
 60 
 
 ie 
 
 •69 
 
 14 
 
 21 
 
 28 
 
 34 
 
 41 
 
 48 
 
 55 
 
 62 
 
 69 
 
 17 
 
 •78 
 
 16 
 
 23 
 
 31 
 
 39 
 
 47 
 
 54 
 
 62 
 
 70 
 
 78 
 
 18 
 
 ■87 
 
 17 
 
 26 
 
 35 
 
 44 
 
 62 
 
 61 
 
 70 
 
 78 
 
 87 
 
 19 
 
 •97 
 
 19 
 
 29 
 
 39 
 
 49 
 
 58 
 
 68 
 
 78 
 
 87 
 
 97 
 
 20 
 
 1-07 
 
 22 
 
 32 
 
 43 
 
 54 
 
 65 
 
 75 
 
 86 
 
 97 
 
 107 
 
 21 
 
 1T9 
 
 24 
 
 36 
 
 47 
 
 59 
 
 71 
 
 83 
 
 95 
 
 107 
 
 119 
 
 22 
 
 1-30 
 
 26 
 
 39 
 
 52 
 
 65 
 
 78 
 
 91 
 
 104 
 
 117 
 
 130 
 
 23 
 
 1-42 
 
 28 
 
 43 
 
 57 
 
 71 
 
 85 
 
 100 
 
 114 
 
 128 
 
 142 
 
 24 
 
 T55 
 
 31 
 
 47 
 
 62 
 
 78 
 
 93 
 
 109 
 
 124 
 
 140 
 
 155 
 
 25 
 
 1-68 
 
 34 
 
 50 
 
 67 
 
 84 
 
 101 
 
 118 
 
 134 
 
 151 
 
 168 
 
 26 
 
 1-82 
 
 36 
 
 55 
 
 73 
 
 91 
 
 109 
 
 127 
 
 146 
 
 164 
 
 182 
 
 27 
 
 1-96 
 
 39 
 
 59 
 
 78 
 
 9S 
 
 118 
 
 137 
 
 157 
 
 176 
 
 196 
 
 28 
 
 2T1 
 
 42 
 
 63 
 
 84 
 
 106 
 
 127 
 
 148 
 
 169 
 
 190 
 
 211 
 
 29 
 
 2-26 
 
 45 
 
 68 
 
 90 
 
 113 
 
 136 
 
 158 
 
 181 
 
 203 
 
 226 
 
 30 
 
 242 
 
 48 
 
 73 
 
 97 
 
 121 
 
 145 
 
 169 
 
 194 
 
 218 
 
 242 
 
 31 
 
 2-58 
 
 52 
 
 77 
 
 103 
 
 129 
 
 155 
 
 181 
 
 206 
 
 232 
 
 258 
 
 32 
 
 2 75 
 
 55 
 
 83 
 
 110 
 
 138 
 
 165 
 
 193 
 
 220 
 
 248 
 
 275 
 
 33 
 
 2-93 
 
 59 
 
 88 
 
 117 
 
 147 
 
 176 
 
 205 
 
 234 
 
 264 
 
 293 
 
 34 
 
 3T1 
 
 62 
 
 93 
 
 124 
 
 156 
 
 187 
 
 218 
 
 249 
 
 280 
 
 311 
 
 35 
 
 3-29 
 
 66 
 
 99 
 
 132 
 
 165 
 
 197 
 
 230 
 
 263 
 
 296 
 
 329 
 
 36 
 
 3-48 
 
 70 
 
 104 
 
 139 
 
 174 
 
 209 
 
 244 
 
 278 
 
 313 
 
 348 
 
 37 
 
 3'68 
 
 74 
 
 110 
 
 147 
 
 184 
 
 221 
 
 258 
 
 294 
 
 331 
 
 368 
 
 38 
 
 3-88 
 
 78 
 
 116 
 
 155 
 
 194 
 
 233 
 
 272 
 
 310 
 
 349 
 
 388 
 
 39 
 
 4-09 
 
 82 
 
 123 
 
 164 
 
 205 
 
 245 
 
 287 
 
 327 
 
 368 
 
 409 
 
 40 
 
 4-30 
 
 86 
 
 129 
 
 172 
 
 215. 
 
 258 
 
 301 
 
 344 
 
 387 
 
 430 
 
 41 
 
 4’52 
 
 90 
 
 136 
 
 181 
 
 226 
 
 271 
 
 316 
 
 362 
 
 407 
 
 452 
 
 42 
 
 4-74 
 
 95 
 
 142 
 
 190 
 
 237 
 
 284 
 
 332 
 
 379 
 
 427 
 
 474 
 
 43 
 
 497 
 
 99 
 
 149 
 
 199 
 
 249 
 
 298 
 
 348 
 
 398 
 
 447 
 
 497 
 
 44 
 
 5-20 
 
 104 
 
 156 
 
 208 
 
 260 
 
 312 
 
 364 
 
 416 
 
 468 
 
 520 
 
 45 
 
 544 
 
 109 
 
 163 
 
 218 
 
 272 
 
 326 
 
 3S1 
 
 435 
 
 489 
 
 544 
 
 46 
 
 569 
 
 114 
 
 171 
 
 228 
 
 285 
 
 341 
 
 398 
 
 455 
 
 512 
 
 669 
 
 47 
 
 594 
 
 119 
 
 178 
 
 238 
 
 297 
 
 356 
 
 416 
 
 475 
 
 535 
 
 594 
 
 48 
 
 6T9 
 
 124 
 
 186 
 
 248 
 
 310 
 
 371 
 
 433 
 
 495 
 
 557 
 
 619 
 
 49 
 
 6 45 
 
 129 
 
 194 
 
 258 
 
 323 
 
 387 
 
 452 
 
 516 
 
 581 
 
 645 
 
 50 
 
 6-72 
 
 134 
 
 202 
 
 269 
 
 336 
 
 403 
 
 470 
 
 538 
 
 605 
 
 672 
 
 Of the friction of the cars of a train- — From experiments, the mean friction of the cars taken inde- 
 pendently of the resistance of the air, amounts to of their gross weight, or to 5’76 pounds per ton ; 
 but to simplify the calculations we will take it at 6 pounds per ton, which makes T l^ of the weight ol 
 the cars. 
 
 These are the results which ought to be rised when, for the resistance of the air, the determination 
 deduced from the most recent and most exact experiments on the subject is used, and when account is 
 
254 
 
 LOCOMOTIVE ENGINE. 
 
 taken, as it ought to be, of the length of the prism formed by the train in motion, as well as of the 
 effects of the air against the rotation of the wheels and the accessory parts of the wagons. 
 
 It appears from this result that for the mean velocity of trains it would be indifferent to compute the 
 friction of the cars at 5'7 6 pounds per ton, taking account of the real resistance of the air and of its 
 effects against the accessory parts noticed above, or to take the friction of the wagons at 7 pounds per 
 ton, accounting merely for the resistance of the air against the wagon of greatest section. On the other 
 hand, as during the work of the engines their velocity is so much the greater as the train they draw is 
 less considerable, whence the resistance of the air increases as the friction of the train diminishes, it will 
 be found that either of the two preceding calculations leads to very nearly the same result, for the total 
 resistance opposed by the moving train, and that it is only in cases of extreme velocity that the two 
 modes of calculation present a notable difference. 
 
 Without any important error, the second of the two modes of calculation may be used ; but the first 
 is introduced with a view to the exhibition of a general formula. 
 
 It should be premised that the valuation of the friction, which we obtained above, ought to be under- 
 stood only of carriages similar to those which were submitted to experiment, and subject to like condi- 
 tions, viz., with iron axles, turning on brass chairs, and provided with self-acting grease-boxes ; with three- 
 feet wheels and axle-bearings If inches; with the use of a well-kept railway, and finally with the 
 '.csual proportions of about | between the weight of the body of the loaded carriage and the total weight 
 of the wagon. Were these conditions materially altered, a new determination of the friction would be- 
 come necessary. 
 
 Of gravity on inclined planes. — We have seen how the resistance caused on a railway by the friction 
 of the wagons may be valued. But it sometimes happens that this friction is the smallest part of the 
 total resistance which the engine has to overcome, in order to effect the motion of the train. This case 
 occurs when the way is not level, and the train is obliged to ascend an acclivity. The resistance then 
 caused is, as every one knows, much greater than on a level line, and in consequence it becomes neces- 
 sary to take account of it in the calculations. 
 
 When a body is placed on an inclined plane, the weight vhich urges it, and which always acts in a 
 vertical line, is decomposed into two forces ; one perpendicular to the plane, and which measures the 
 pressure produced against the plane, by virtue of the weight of the moving body, and the other parallel 
 to the plane, and which tends to make the body slide or roll along the declivity. The latter force, which 
 we will call the gravity along the plane, would inevitably drag the body towards the foot of the declivity, 
 were it not counteracted by a contrary force. When therefore a train of wagons has to ascend an in- 
 clined plane, the moving power must apply to it : firstly, a force able to overcome the friction of the 
 wagons themselves ; and again, another force able to overcome the gravity in the direction of the plane. 
 If, on the contrary, the mover draw the train of wagons down the plane, then, in order to produce the 
 motion, it will evidently have to apply only a force equal to the difference between the friction proper 
 to the wagons and the gravity, since the latter force then acts in the same direction as the mover. 
 
 When a body of a given weight is set on a plane of a given inclination, we know that, in order to ob- 
 tain the gravity of the body along the plane, its weight is to be multiplied by the fraction which ex- 
 presses practically the inclination of the plane. Thus, for instance, on a plane inclined fg, that is to say, 
 on a plane which rises 1 foot on a length of 89 feet measured along the acclivity, the gravity of 1 ton, 
 or 2240 lbs., is 
 
 2240 
 
 = 25-2 lbs. 
 
 89 
 
 Moreover, when a train of wagons ascends an acclivity, the engine has not only to surmount the grav- 
 ity of the wagons of the train, but likewise its own gravity and that of the tender which follows it ; and 
 these forces do not present themselves when the motion takes place on a horizontal line. It is then on 
 the total weight of the train, that is, including engine and tender, that the resistance caused by gravity 
 on acclivities is to be calculated. 
 
 If it be supposed, for instance, that a train of 40 tons, tender included, be drawn up a plane inclined 
 ■gL, by an engine weighing 10 tons, it is clear that the definitive resistance opposed to the motion by the 
 
 train will be 
 
 40 X 6 lbs. = 240 lbs., friction of the carriages at 6 lbs. per ton 240 lbs. 
 
 50 X -2.||- = 1258 lbs., gravity of the 50 tons of the train (reduced to lbs.) on a plane 
 
 inclined fg, to be added 1258 
 
 Total resistance arising from friction and gravity 1498 lbs. 
 
 If, on the contrary, the same train had to descend a plane inclined j- T Vo> the resistance it would then 
 offer would be 
 
 40 X 6 lbs. - 240 lbs., friction of the wagons 240 lbs. 
 
 50 X ffjyg = 112 lbs., gravity of the train to be deducted 112 
 
 Definitive resistance arising from friction and gravity 128 lbs. 
 
 In general, let M be the weight of the train, in tons gross and including the tender ; let m be the 
 weight of the engine, expressed also in tons ; k the friction of the wagons per ton, expressed in lbs., as 
 has been explained ; finally, let g be the gravity, in lbs., of 1 ton on the plane in question. It is clear 
 in the first place, from what has been said above, that the quantity g will be equal to 2240, multiplied 
 
 by the practical inclination of the plane ; so that if — express that inclination, or the ratio of the height 
 
 of the plane to its length, we shall have, to determine y, the equation 
 
 2240 
 
LOCOMOTIVE ENGINE. 
 
 25 £ 
 
 This premised, the friction of the wagons will have for its value k M. Again, since g expresses tho 
 gravity of 1 ton, it is plain that g (M -+- in) will represent, in lbs., the gravity of the total mass, train 
 and engine, placed on the inclined plane. 
 
 Thus, according as the motion takes place in ascending or in descending, the total resistance, in lbs., 
 offered by the train on the inclined plane, will be 
 
 k M + g (M -f- in) — (k + g) M + g in, 
 
 an expression in which the sign + belongs to the ascending motion, and the sign — to the descending 
 motion of the train. 
 
 It will always be easy then to obtain the number of lbs., which represents the resistance opposed by 
 a train in motion on a plane of a given inclination. 
 
 Of the effects of the blast-pipe . — We have just examined several of the resistances which are opposed 
 to the engine in its motion, viz., that of the wagons along the rails, and that of the air against the trains. 
 But among other resistances which the piston has yet to overcome, is one arising from the disposition 
 of the engine itself, and of which it will be proper to treat before proceeding further. 
 
 The steam, after having exerted its action in the cylinder, might escape into the atmosphere by a 
 large opening. It would then be possible for it entirely to dissipate itself in the air, during the time the 
 piston takes to change its direction. Consequently the steam would in nowise impede the retrograde 
 motion of the piston, whatever might be the velocity of the piston. But the disposition adopted is con- 
 trary to this. The steam, on leaving the cylinder, has no other issue towards the atmosphere than an 
 aperture exceedingly narrow ; nor can it, by that aperture, escape totally within the time of one stroke, 
 except by assuming a very considerable velocity in its motion. For this, the steam in the cylinder must 
 necessarily be at a pressure sensibly greater than that of the atmosphere into which it flows ; and as 
 the pressure of the steam while flowing acts in all directions, and consequently against the piston, it 
 results that the latter, instead of having simply to counteract the atmospheric pressure, finds an addi- 
 tional one to overcome, which is to be added to the divers resistances already measured. 
 
 This new cause of resistance might, as has been said, be in a great measure suppressed, by enlarging 
 sufficiently the outlet of the steam. But to do this would be to lose one of the most active causes of 
 the definitive effect of the engine ; for the object of the disposition of which we treat is to excite the fire 
 sufficiently, and to produce, in a boiler of small dimensions, the very great quantity of steam requisite 
 for the rapid motion of the engine. To this end, the waste steam is conducted to the chimney, and 
 thrown into it by intermittent jets, through a blast-pipe or contracted tube, placed in the centre of the 
 chimney and directed upwards. The jet of steam, as it rushes with force from this aperture, rapidly 
 expels the gases which occupied the chimney. It consequently leaves behind it a vacuum ; and this is 
 immediately filled by a mass of air rushing through the fire-grate into the space where the vacuum has 
 been made. At every aspiration thus produced, the fuel contained in the fire-box grows white with 
 incandescence. The effect then is similar to that of a bellows continually urging the fire ; and the arti- 
 ficial current created in the fire-box by this means is of such efficacy for the vaporization, that were the 
 blast-pipe suppressed, the engine would become almost useless, which proves that the current of air 
 attributable to the ordinary draught of the chimney is in comparison but very trifling. 
 
 Omitting the experiments and calculations from which it is derived, we obtain as the value of the 
 resistance against the piston caused by the action of the blast-pipe, the formula 
 
 S' 
 
 •0113 v — ; 
 o 
 
 in which v is the velocity of the engine in miles per hour : S' the total vaporization of the boiler in cubic 
 feet of water per hour ; o the area of the orifice of the blast-pipe expressed in square inches ; and the 
 result of the calculation will give the pressure in the blast-pipe expressed in pounds per square inch. 
 The pressure per square foot will be 144 times as much. 
 
 With respect to the quantity represented here by S', the experiment from which we deduced the 
 formula shows, that the vaporization signified is tne total vaporization effected in the boiler, that is to 
 say, the vaporization counted before deduction of the water carried away in a liquid state with the steam. 
 
 Making in the preceding formula 
 
 •0113 S =r/, 
 o 
 
 the pressure in the blast-pipe may be represented by the expression p' v, m which p' will be the ratio 
 of the vaporization to the orifice of the blast-pipe, multiplied by a constant coefficient. 
 
 Now, for engines which vaporize as much as 60 cubic feet of water per hour, practice has established 
 the use of a blast-pipe of 2'23 inches diameter, or 3’96 square inches of area, which gives for the value 
 
 of the ratio 
 
 60 
 
 3'96 
 
 = 15-2. 
 
 In constructing engines of a greater vaporizing power, it would be natural to increase the area of the 
 blast-pipe in proportion to the quantity of steam to which it is to give issue. There is room therefore 
 to think that the proportion thus established between the production of steam and the area of the blast- 
 s' 
 
 pipe, will not be notably changed by the different engine-makers. Consequently the ratio — may be 
 
 regarded approximatively as a constant quantity, given by the above proportion. 
 
 Then the preceding formula will be reduced simply to the expression T75 v, which will be 
 useful especially in valuing the pressure due to the blast-pipe in engines whose vaporization is 
 
‘256 
 
 LOCOMOTIVE ENGINE. 
 
 unknown. In this formula, v is the velocity of the engine, in miles per hour, and the result is the 
 pressure in the blast-pipe, expressed in pounds per square inch. As the pressure per square foot is 144 
 times as much, it follows that if we require the pressure expressed in that manner, we shall obtain its 
 value by the formula 25'2 v. 
 
 We shall then represent generally the pressure in the blast pipe under the form p' v\ and for 
 the most ordinary cases, it will suffice to give to p‘, in this expression, one of the constant values 
 above mentioned, according to the measures employed. But if the engine in question should differ too 
 considerably from the proportions which we have just indicated with reference to the area of the blast- 
 pipe, it would be necessary to substitute for that approximate value of pi’, its value function of S' and o. 
 
 In line, to dispense with all calculation on this head, we here subjoin a table, in which will be found, 
 on inspection, the pressures in the blast-pipe for given circumstances, and we continue that table beyond 
 the actual effects of locomotive engines. It will there be recognized how, by augmenting the orifice of 
 the blast-pipe, the resistance against the piston, arising from that cause, may be diminished at pleasure ; 
 and it may probably be found, in consequence, that in the regular work of locomotives, it might be use- 
 ful to adopt a blast-pipe with a variable orifice, such as was employed temporarily in the experiments 
 from which these values were deduced. Then, by contracting the orifice of efflux of the steam only 
 just as much as is necessary, there will be no more resistance against the piston than what is indispen- 
 sable for the proper action of the engine. 
 
 Practical Table of the pressures against the piston, due to the action of the blast-pipe. 
 
 Diumeter of 
 the blast-pipe. 
 
 Velocity 
 of the 
 engine, in 
 miles per 
 hour. 
 
 Effective pressure against the piston, in lbs. per square inch, the vaporization 
 of the boiler, in cubic feet of water per hour, being: 
 
 30 
 
 40 
 
 50 
 
 00 
 
 70 
 
 80 
 
 90 
 
 100 
 
 
 miles. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 2 inches. 
 
 5 
 
 0*5 
 
 0-7 
 
 0-9 
 
 11 
 
 1-3 
 
 
 „ 
 
 
 
 10 
 
 IT 
 
 1-4 
 
 1-8 
 
 2*2 
 
 2'5 
 
 
 
 >» 
 
 
 15 
 
 1-G 
 
 2*2 
 
 2-7 
 
 32 
 
 3-8 
 
 
 „ 
 
 
 
 20 
 
 2*2 
 
 2-9 
 
 3-6 
 
 4-3 
 
 5*0 
 
 f} 
 
 * 
 
 
 
 25 
 
 2-7 
 
 3-6 
 
 45 
 
 51 
 
 6'3 
 
 
 
 » 
 
 
 30 
 
 3-2 
 
 4-3 
 
 51 
 
 65 
 
 7-6 
 
 }} 
 
 v 
 
 
 
 35 
 
 3-8 
 
 5-0 
 
 63 
 
 7-0 
 
 8-8 
 
 n 
 
 
 
 
 40 
 
 4-3 
 
 5-8 
 
 7-2 
 
 8-6 
 
 101 
 
 ’< 
 
 „ 
 
 » 
 
 2 1 inches. 
 
 5 
 
 OT 
 
 0'6 
 
 0-7 
 
 0-9 
 
 1-0 
 
 1-1 
 
 
 V 
 
 
 10 
 
 0'9 
 
 IT 
 
 11 
 
 1-7 
 
 2-0 
 
 2-3 
 
 
 
 
 15 
 
 1-3 
 
 1-7 
 
 21 
 
 2-6 
 
 30 
 
 31 
 
 
 
 
 20 
 
 1-7 
 
 23 
 
 2-8 
 
 31 
 
 4-0 
 
 4-5 
 
 
 
 
 25 
 
 21 
 
 2-8 
 
 3-G 
 
 4 3 
 
 50 
 
 5-7 
 
 
 JJ 
 
 
 30 
 
 2-6 
 
 3T 
 
 4-3 
 
 5*1 
 
 G'O 
 
 6-8 
 
 
 
 
 35 
 
 3-0 
 
 4-0 
 
 5-0 
 
 6-0 
 
 7-0 
 
 80 
 
 
 
 
 40 
 
 31 
 
 4 5 
 
 5-7 
 
 6’8 
 
 8-0 
 
 91 
 
 - 
 
 » 
 
 2A inches. 
 
 5 
 
 0 3 
 
 0-5 
 
 06 
 
 0-7 
 
 0-8 
 
 09 
 
 1-0 
 
 ?> 
 
 
 10 
 
 0'7 
 
 09 
 
 1-2 
 
 11 
 
 1-6 
 
 1-8 
 
 2-1 
 
 »» 
 
 
 15 
 
 1-0 
 
 1-4 
 
 1-7 
 
 21 
 
 21 
 
 2-S 
 
 31 
 
 
 
 20 
 
 1-4 
 
 1-8 
 
 2-3 
 
 2-8 
 
 3-2 
 
 37 
 
 4-1 
 
 
 
 25 
 
 1-7 
 
 2-3 
 
 2'9 
 
 3-5 
 
 4-0 
 
 4*6 
 
 5-2 
 
 „ 
 
 
 80 
 
 21 
 
 2-8 
 
 35 
 
 41 
 
 4-8 
 
 5*5 
 
 6-2 
 
 
 
 35 
 
 21 
 
 3-2 
 
 4-0 
 
 4-8 
 
 56 
 
 61 
 
 7-3 
 
 »> 
 
 
 40 
 
 2-8 
 
 3-7 
 
 4-6 
 
 5*5 
 
 6-4 
 
 71 
 
 8-3 
 
 >> 
 
 
 45 
 
 3 1 
 
 41 
 
 5-2 
 
 6-2 
 
 7-3 
 
 8-3 
 
 9-3 
 
 y> 
 
 
 50 
 
 3-5 
 
 4-tl 
 
 5-8 
 
 6*9 
 
 81 
 
 92 
 
 101 
 
 n 
 
 2J inches. 
 
 5 
 
 0-3 
 
 01 
 
 0 5 
 
 0-6 
 
 0-7 
 
 0-8 
 
 0-9 
 
 1-0 
 
 
 10 
 
 0'6 
 
 0-8 
 
 1-0 
 
 11 
 
 1-3 
 
 1*5 
 
 1-7 
 
 1-9 
 
 
 15 
 
 0-9 
 
 11 
 
 11 
 
 1-7 
 
 2-0 
 
 2-3 
 
 2-6 
 
 2-9 
 
 
 20 
 
 11 
 
 1-5 
 
 1-9 
 
 23 
 
 2-7 
 
 3-0 
 
 31 
 
 3-8 
 
 
 25 
 
 1-4 
 
 1-9 
 
 2-4 
 
 29 
 
 33 
 
 3-8 
 
 4-3 
 
 4-8 
 
 
 30 
 
 1-7 
 
 2-3 
 
 29 
 
 31 
 
 4-0 
 
 4-6 
 
 5-1 
 
 5-7 
 
 
 35 
 
 2-0 
 
 2-7 
 
 33 
 
 4-0 
 
 4-7 
 
 53 
 
 60 
 
 6-7 
 
 
 40 
 
 2-3 
 
 3-0 
 
 3-8 
 
 4-6 
 
 53 
 
 61 
 
 68 
 
 7-6 
 
 
 45 
 
 2-6 
 
 34 
 
 4-3 
 
 51 
 
 6-0 
 
 68 
 
 7-7 
 
 8 6 
 
 
 50 
 
 2-9 
 
 38 
 
 48 
 
 57 
 
 6-7 
 
 7'6 
 
 8'6 
 
 95 
 
LOCOMOTIVE ENGINE. 
 
 257 
 
 1 
 
 Jiameter of 
 the blast-pipe. 
 
 Velocity 
 of the 
 engine, in 
 miles per 
 hour. 
 
 Effective pressure against the piston, in lbs. per square inch, the vaporization 
 of ttie boiler, in cubic feet of water per hour, being: 
 
 30 
 
 40 
 
 50 
 
 60 
 
 TO 
 
 80 
 
 90 
 
 100 
 
 
 miles. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 lbs. 
 
 3 inches. 
 
 5 
 
 0'2 
 
 0-3 
 
 0'4 
 
 0-5 
 
 0-6 
 
 0-6 
 
 0-7 
 
 0-8 
 
 
 10 
 
 0'5 
 
 0-6 
 
 0-8 
 
 1-0 
 
 IT 
 
 1-3 
 
 14 
 
 1-6 
 
 
 15 
 
 0-7 
 
 1-0 
 
 1-2 
 
 1-4 
 
 1-7 
 
 1-9 
 
 2-2 
 
 24 
 
 
 20 
 
 10 
 
 1-3 
 
 1-6 
 
 1-9 
 
 2-2 
 
 2-6 
 
 29 
 
 32 
 
 
 25 
 
 1'2 
 
 1-6 
 
 2-0 
 
 2-4 
 
 2-8 
 
 3-2 
 
 36 
 
 40 
 
 
 30 
 
 1-4 
 
 1'9 
 
 2-4 
 
 2-9 
 
 34 
 
 3-8 
 
 4 3 
 
 4-8 
 
 
 35 
 
 1-7 
 
 2'2 
 
 2-8 
 
 3-4 
 
 3-9 
 
 4-5 
 
 5-0 
 
 66 
 
 
 40 
 
 1-9 
 
 26 
 
 3-2 
 
 3-8 
 
 4-5 
 
 51 
 
 6-8 
 
 64 
 
 
 45 
 
 2'2 
 
 2-9 
 
 3-6 
 
 4'3 
 
 5 0 
 
 5-8 
 
 65 
 
 7-2 
 
 
 60 
 
 2-4 
 
 82 
 
 4-0 
 
 4-8 
 
 5-0 
 
 64 
 
 7-2 
 
 8-0 
 
 
 55 
 
 2-6 
 
 3-5 
 
 4-4 
 
 5-3 
 
 62 
 
 7-0 
 
 7-9 
 
 8-8 
 
 
 60 
 
 29 
 
 3-8 
 
 4-8 
 
 5-8 
 
 6-7 
 
 7-7 
 
 86 
 
 96 
 
 3J inches. 
 
 5 
 
 0-2 
 
 0-3 
 
 0-3 
 
 0-4 
 
 05 
 
 0-5 
 
 0'6 
 
 0-7 
 
 
 10 
 
 0-4 
 
 05 
 
 0'7 
 
 0-8 
 
 1-0 
 
 IT 
 
 1-2 
 
 14 
 
 
 15 
 
 06 
 
 08 
 
 10 
 
 1-2 
 
 14 
 
 1-6 
 
 1-8 
 
 20 
 
 
 20 
 
 0-8 
 
 IT 
 
 1-4 
 
 1-6 
 
 1-9 
 
 22 
 
 24 
 
 2-7 
 
 
 25 
 
 1-0 
 
 1-4 
 
 1-7 
 
 2T 
 
 24 
 
 2-7 
 
 8T 
 
 34 
 
 
 30 
 
 1-2 
 
 1-6 
 
 2-0 
 
 2-5 
 
 29 
 
 33 
 
 37 
 
 44 
 
 
 35 
 
 1-4 
 
 1-9 
 
 24 
 
 2-9 
 
 3-3 
 
 3'8 
 
 4-3 
 
 4-8 
 
 
 40 
 
 1-6 
 
 2-2 
 
 2-7 
 
 3 3 
 
 38 
 
 44 
 
 4-9 
 
 64 
 
 
 45 
 
 1-8 
 
 2-4 
 
 3T 
 
 3-7 
 
 4-3 
 
 4-9 
 
 55 
 
 6T 
 
 
 50 
 
 2-0 
 
 2-7 
 
 3-4 
 
 4T 
 
 4-8 
 
 54 
 
 64 
 
 6-8 
 
 
 55 
 
 2-2 
 
 3-0 
 
 3-7 
 
 4-5 
 
 62 
 
 60 
 
 6-7 
 
 7'5 
 
 
 60 
 
 2-4 
 
 3-2 
 
 4-1 
 
 4-9 
 
 5-7 
 
 65 
 
 7-3 
 
 8'2 
 
 3-J- inches. 
 
 5 
 
 0-2 
 
 0-2 
 
 03 
 
 0-4 
 
 04 
 
 0-5 
 
 05 
 
 06 
 
 
 10 
 
 0-4 
 
 0*5 
 
 0-6 
 
 0-7 
 
 0-8 
 
 0-9 
 
 IT 
 
 1-2 
 
 
 15 
 
 05 
 
 0-7 
 
 0'9 
 
 IT 
 
 1-2 
 
 14 
 
 1-6 
 
 1-8 
 
 
 20 
 
 0-7 
 
 0-9 
 
 1-2 
 
 1-4 
 
 1-6 
 
 1-9 
 
 2T 
 
 23 
 
 
 25 
 
 0-9 
 
 1-2 
 
 1-5 
 
 1-8 
 
 2T 
 
 24 
 
 2-7 
 
 29 
 
 
 30 
 
 11 
 
 1-4 
 
 1-7 
 
 24 
 
 25 
 
 28 
 
 32 
 
 35 
 
 
 36 
 
 1-2 
 
 1-6 
 
 2-0 
 
 25 
 
 2'9 
 
 3-3 
 
 3-7 
 
 4T 
 
 
 40 
 
 1-4 
 
 1-9 
 
 23 
 
 2-8 
 
 33 
 
 3-8 
 
 4-2 
 
 4-7 
 
 
 45 
 
 1-6 
 
 2'1 
 
 26 
 
 3-2 
 
 3-7 
 
 4-2 
 
 4-8 
 
 53 
 
 
 50 
 
 1-8 
 
 2-4 
 
 2-9 
 
 3-5 
 
 41 
 
 4-7 
 
 5-3 
 
 5-9 
 
 
 55 
 
 1-9 
 
 2-6 
 
 32 
 
 3-9 
 
 4-5 
 
 5-2 
 
 5-8 
 
 6-5 
 
 
 60 
 
 2-1 
 
 2-8 
 
 3o 
 
 4-2 
 
 49 
 
 56 
 
 64 
 
 7-0 
 
 3| inches. 
 
 5 
 
 02 
 
 02 
 
 0-3 
 
 0-3 
 
 04 
 
 04 
 
 05 
 
 0-5 
 
 
 10 
 
 0-3 
 
 04 
 
 0*5 
 
 0'6 
 
 0-7 
 
 08 
 
 09 
 
 1-0 
 
 
 15 
 
 05 
 
 06 
 
 0-8 
 
 0-9 
 
 IT 
 
 1-2 
 
 14 
 
 1-5 
 
 
 20 
 
 0-6 
 
 0-8 
 
 10 
 
 1-2 
 
 14 
 
 16 
 
 1-8 
 
 2-0 
 
 
 25 
 
 0'8 
 
 1-0 
 
 13 
 
 1*5 
 
 1-8 
 
 21 
 
 23 
 
 26 
 
 
 30 
 
 0-9 
 
 1-2 
 
 1-5 
 
 1-8 
 
 2T 
 
 25 
 
 2-8 
 
 31 
 
 
 35 
 
 1-1 
 
 1-4 
 
 1-8 
 
 2T 
 
 25 
 
 2-9 
 
 32 
 
 36 
 
 
 40 
 
 1-2 
 
 1-6 
 
 20 
 
 25 
 
 29 
 
 33 
 
 37 
 
 44 
 
 
 45 
 
 1-4 
 
 1-8 
 
 2-3 
 
 2-8 
 
 32 
 
 3-7 
 
 41 
 
 46 
 
 
 50 
 
 1-5 
 
 21 
 
 26 
 
 3T 
 
 3'6 
 
 4T 
 
 4-6 
 
 54 
 
 
 55 
 
 1-7 
 
 23 
 
 2-8 
 
 34 
 
 39 
 
 45 
 
 61 
 
 5-6 
 
 
 60 
 
 1-8 
 
 25 
 
 ST 
 
 3'7 
 
 43 
 
 4-9 
 
 55 
 
 64 
 
 4 inches. 
 
 6 
 
 0 1 
 
 0-2 
 
 0-2 
 
 0-3 
 
 03 
 
 04 
 
 04 
 
 05 
 
 
 10 
 
 03 
 
 0-4 
 
 0-5 
 
 0‘5 
 
 06 
 
 0-7 
 
 0-8 
 
 09 
 
 
 15 
 
 04 
 
 0-5 
 
 0'7 
 
 0-8 
 
 0-9 
 
 IT 
 
 1-2 
 
 14 
 
 
 20 
 
 0-5 
 
 0-7 
 
 09 
 
 IT 
 
 1-3 
 
 14 
 
 1-6 
 
 1-8 
 
 
 25 
 
 0-7 
 
 09 
 
 IT 
 
 1-4 
 
 1-6 
 
 1-8 
 
 2-0 
 
 23 
 
 
 30 
 
 08 
 
 IT 
 
 1-4 
 
 1-6 
 
 1-9 
 
 22 
 
 24 
 
 2-7 
 
 
 35 
 
 0-9 
 
 1-3 
 
 1-6 
 
 1-9 
 
 2 2 
 
 25 
 
 2-8 
 
 3-2 
 
 
 40 
 
 11 
 
 1-4 
 
 1-8 
 
 2-2 
 
 25 
 
 2-9 
 
 3-2 
 
 36 
 
 
 45 
 
 1-2 
 
 1-6 
 
 20 
 
 24 
 
 28 
 
 3-2 
 
 36 
 
 44 
 
 
 60 
 
 1-4 
 
 1-8 
 
 23 
 
 2-7 
 
 32 
 
 36 
 
 41 
 
 45 
 
 
 65 
 
 1-5 
 
 2'0 
 
 25 
 
 30 
 
 35 
 
 4-0 
 
 45 
 
 50 
 
 
 60 
 
 1-6 
 
 2 2 
 
 2-7 
 
 32 
 
 38 
 
 43 
 
 49 
 
 64 
 
 Vol. II.— 17 
 
258 
 
 LOCOMOTIVE ENGINE. 
 
 Of the several elements of the friction of locomotive engines. — After having examined the resistance 
 offered by the loads to be moved, it will be proper also to make known the passive resistance or fric- 
 tion of the movers which we have to employ ; for it is only the surplus of their power over and above 
 what is necessary to propel themselves, that these movers can apply to the drawing of burdens. 
 
 While a locomotive engine is performing the traction of a train, it evidently requires : — 1st, a certain 
 force to make the train advance, or to overcome the resistance of all the loaded carriages ; and 2dly, 
 another force to propel itself by overcoming its own friction. It is this second force, that which causes 
 the engine to move, which represents the friction of the engine ; whereas the first is the resistance of 
 the load , and the union of the two efforts constitutes the total force applied by the mover. 
 
 The friction of a locomotive engine is then the force it expends to maintain itself in motion on the 
 rails. But that force must clearly vary according to the weight or resistance of the load which the 
 engine draws. In effect, the greater that weight, the greater also will be the pressure it causes on the 
 axes of rotation, and on the divers moving parts of the apparatus; and as the friction is always in 
 proportion to the pressure, it follows that the friction which takes place at these points, must augment 
 with the load. Hence the friction of the engine, which is nothing more than the force resulting from 
 the union of these different frictions, must equally increase with the load. 
 
 Thus we find a difference between the friction of an engine unloaded , and that of the same engine 
 loaded. The value of the first is found to be 15 lbs. per ton of their weight, and of the second, T37 lbs. 
 additional per pound of traction in the case of uncoupled driving-wheels, and '215 lbs. per pound of 
 traction in the case of engines with wheels coupled. 
 
 It will readily be conceived, however, that it must vary some with the construction and state of every 
 engine. 
 
 With reference to the manner in which the additional friction of engines ought to be calculated, we 
 have to bear in mind that it is to be reckoned on every pound of the total resistance exerted against the 
 motion ; that is to say, the resistance caused by the friction of the wagons, that of gravity, and that of 
 the atmosphere, must first be calculated, and on the sum of these the additional friction of the engine is to 
 be taken at the rate already indicated. 
 
 Of the total resistance on the piston, resulting from the divers partial resistances just enumerated . — 
 We have just estimated successively the divers resistances which oppose the motion of the engine. It 
 is necessary now to seek the definitive resistance which results from them united, per square inch or 
 per unit of surface of the area of the piston. 
 
 The resistances which we have hitherto considered are — the resistance of the air, the friction of the 
 wagons, the gravity, the friction of the engines, and the resistance arising from the blast-pipe. But we 
 must here add, besides, the atmospheric pressure ; for the engines under consideration being high- 
 pressure engines, it follows that the opposite face of the piston necessarily supports, like every other 
 uody in communication with the atmosphere, a certain pressure due to the elasticity of the atmos- 
 pheric air. 
 
 Thus, the definitive resistance exerted against the piston consists of six resistances, which are — the 
 friction of the wagons, the resistance of the air, the gravity of the train, the friction of the engine, the 
 atmospheric pressure, and the pressure caused by the blast-pipe. Of these six resistances, the last two 
 act immediately and directly on the piston. 'They must therefore be moved at the velocity of the 
 piston itself ; but it is not so with the other four. In an engine, the pressures exerted on different points 
 by the same force, are in the inverse ratio of the velocities of those points. Here the engine and its 
 train must be moved at a velocity greater than that of the piston, in the proportion of the circumference 
 of the wheel, to twice the length of the stroke. The intensity of the pressure exerted by the resistance 
 of the load, the air, the engine, and the gravity, is then increased by its transmission to the piston, in the 
 above ratio of the velocity of the wheel to that of the piston. 
 
 Consequently, if M express the number of tons gross which compose the total load, that is to say, 
 including the weight of the tender-carriage of the engine, and k the number of pounds requisite to draw 
 one ton on a railway, 
 
 k M 
 
 will be the resistance, in pounds, resulting from the friction of the wagons which carry the load. If at 
 the same time we call g the gravity of 1 ton on the inclined plane to be traversed by the engine, and if 
 m represent the weight of the engine, in tons, 
 
 g (M -f m) 
 
 will be the resistance, in pounds, produced by the gravity of the total mass, train and engine ; so that, 
 according as the motion takes place in ascending or in descending, the definitive resistance arising from 
 friction and gravity will be 
 
 k M ±g (M + m ) = (k±g) M ±gm. 
 
 Similarly, if we express by u v 2 the resistance, in pounds, exerted by the air against the train, at the 
 velocity v of the engine, 
 
 (k±g)ll±gm + u v 2 
 
 will be the resistance opposed to the motion of the engine by the friction, the gravity, and the shock of 
 the air. 
 
 If, again, F represent the friction of the unloaded engine, expressed also in pounds, and <5 its additional 
 friction, measured as a fraction of the resistance, as has been already indicated, we see that 
 
 F -f <5 [ (k±g) M ±g m -f u v-] 
 
 will be the total friction of the engine at the moment when it draws the resistance 
 
 ( k '±$0 M m + u v 1 . 
 
LOCOMOTIVE ENGINE. 
 
 259 
 
 Consequently 
 
 (1 + 0 [ (£±<7) M±f7 m + u V] + F 
 
 will be the total resistance opposed to the progression, along the rails, by the engine and its train. 
 
 As this force produces on the piston a resistance augmented in the ratio of the circumference of the 
 wheel to twice the stroke of the piston, if D express the diameter of the wheel, l the length of the 
 stroke, and n the ratio of the circumference to the diameter, 
 
 0 + s ) [ (^dt#) <7 m + u Yi "t" o i 
 
 will be the resistance on the piston, caused by that force, that is to say, caused by the resistance of the 
 wagons, the gravity, the air, and the friction of the engine. 
 
 This resistance is that which is exerted on the totality of the area of the pistons. But representing 
 by <1 the diameter of the cylinders, d" will be the area of the two pistons. Whence 
 
 (1 + [ {k±cj) M ±g m + 
 
 ’ 
 
 or, simplifying, 
 
 (l + «) [(*±S0M ±c l m + uP]~ + ^- l , 
 
 will be the same force, divided according to the unit of surface of the piston. 
 
 Adding to this the atmospheric pressure p, and the pressure caused by the blast-pipe p' v, which 
 are already measured per unit of surface, we shall have, in fine, for the total resistance R exerted on 
 the piston, 
 
 R = (1 + &) [ (k±ff) M±y m -f u F 2 ] ~ + 5Z + p -fy/ v _ 
 
 In this expression, the quantity g represents the gravity on the plane to be traversed by the train ; if 
 the plane be horizontal instead of inclined, we shall have g — o. The weights M and in of the train and 
 the engine are expressed in tons gross ; the quantity k, which is the friction of the wagons per ton, is 
 equal to 6 lbs.; the value of S is T37 or 4, for engines with uncoupled wheels; the velocity v of the 
 engine is expressed in miles per hour; in fine, according as the dimensions D, l and d are expressed in 
 inches or in feet, and the forces u, p and p\ in pounds per square inch, or in pounds per square foot, 
 the value R which will result from the calculation will be the resisting pressure on the piston, expressed 
 likewise in pounds per square inch, or in pounds per square foot. 
 
 Applying this calculation to a train of 9 wagons and a tender, weighing 60 tons gross, and drawn at 
 the velocity of 20 miles per hour, up a plane inclined t^j,, by an engine with two cylinders of 11 inches 
 diameter, stroke of the piston 16 inches, propelling wheels 6 feet, not coupled, weight 8 tons, friction 
 104 lbs., blast- pipe 2'25 inches in diameter; and referring, for the resistance of the air, to what has been 
 said above, the proceeding will be as follows : 
 
 60 X 6 = 300 lbs. Friction of the wagons, in pounds, or value of k m. 
 
 2240 
 
 — — X58 = 260 lbs. Gravity of the total mass, train and engine, or value of g (M -j- in ). 
 
 194 lbs. Resistance of the air against an effective surface of 180 square feet, at the ve- 
 locity of 20 miles per hour or value of u v 1 . 
 
 7 54 lbs. Resistance of the train, or ( k + y) M -f- gm-\- u v 2 . 
 
 ’lo'iXI'IS'l = 857 lb3. Resistance of the train, including the additional friction which it produces in 
 the engine, or (1 -{- 5) [ ( k + g)~M.-\-gm-{-v, w 2 .] 
 
 -f- 104 lbs. Friction of the unloaded engine, or F. 
 
 961 lbs. Total resistance to the progressive motion of the engine, or value of the term 
 (l + i)[(* + fl')M + S Pm + ««»H-F. 
 
 On the other hand, we have 
 
 3T416 X 60 in. = 188’5 Circumference of the wheel, expressed in inches, or z D. 
 
 2X16 in. = 32 Double the stroke of the piston expressed in inches, or 2 7 
 
 - = 5'9 Ratio of the velocities of the wheel and the piston, or L_- 
 
 Thus, 
 
 961X6 9 = 5670 lbs. Resistance produced on the piston, or value of the term 
 
 Again, 
 
 3T416X11 2 
 
 
 = 1 90 Area of tlie two pistons, in square inches, or 4 n d*. 
 
260 
 
 LOCOMOTIVE ENGINE. 
 
 Consequently, we obtain in fine 
 
 5670 
 
 190 
 
 = 29-8 lbs. 
 
 Above-mentioned resistance, portioned per square inch of the surface of the 
 piston. 
 
 - 1 - 3’5 lbs. Effective pressure per square inch, arising from the blast-pipe, or p' v. 
 l-t'7 lbs. Atmospheric pressure per square inch, or p. 
 
 48 0 lbs. Definitive resistance, per square inch of the surface of the piston of an engine 
 with two cylinders of 11 inches in diameter, <Szc., when drawing a load of 50 
 tons under the given circumstances. 
 
 \V ere it desired to know that resistance per square foot, it would suffice to multiply the last result by 
 144, that is to say, the pressure required would be 6912 lbs. per square foot, which number would have 
 been obtained directly, if instead of expressing the area of the piston in square inches, and the partial 
 pressures in pounds per square inch, these measures had been referred to the square foot as unit ol 
 surface. 
 
 This example shows what is to be understood by the different quantities contained in the formula, and 
 how each of them ought to be introduced into the calculation. 
 
 To know the evaporating power of which a given engine is capable, it suffices to measure the number 
 of square feet composing its total heating surface, without distinction between the fire-box and the tubes, 
 and then to multiply that number by the vaporization which each square foot of surface is capable of p>ro- 
 aucing. It is then the latter quantity which we must now seek to determine ; but, as we have seen 
 that the vaporization produced per unit of surface varies with the velocity of the motion, it is necessary 
 to specify at the same time the velocity at which we wish to measure the vaporization. 
 
 We find that in certain engines the vaporization per square foot of heating surface was T98 cubic 
 foot, at the velocity of 1815 miles per hour. On the other hand, we know that the vaporization varies 
 in the direct ratio of the fourth roots of the velocities. We may then deduce from thence, that at the 
 velocity of 20 miles per hour, the vaporization of those engines will be 
 
 / 20 \ i 
 
 T98 S ^ - i ='203 cubic foot of water per square foot of heating surface. 
 
 Operating in the same manner for the two following series, we obtain, for the velocity of 20 miles per 
 hour, the determinations of the following table : 
 
 Experiments on the vaporization of locomotive engines, per unit of total heating surface of their boiur. 
 
 Number of the series. 
 
 Average velocity of 
 the engine in miles 
 per hour. 
 
 Vaporization per hour and per sq. 
 loot of total heating surface, at 
 the preceding velocity. 
 
 Vaporization per hour and per sq. 
 foot of total heating surface, at 
 the velocity of 20 miles per hour. 
 
 
 Miles. 
 
 Cubic foot. 
 
 Cubic foot. 
 
 2d, 
 
 1 8T5 
 
 •198 
 
 •203 
 
 3d, 
 
 20T3 
 
 •200 
 
 •200 
 
 4th, 
 
 8-99 
 
 •172 
 
 •210 
 
 5th, 
 
 15-26 
 
 •194 
 
 •208 
 
 
 
 
 Mean '205 
 
 Thus, from these experiments, it appears that at the velocity of 20 miles per hour, the vaporization 
 of locomotives may be valued at "205, or, in round numbers, at '2 cubic foot of water per hour, per 
 square foot of total heating surface of their boiler ; and it appears also that the different engines and 
 different velocities lead to numbers almost identical, which tends to confirm the valuation we have just 
 obtained. 
 
 This determination is, as we have said, suitable to the velocity of 20 miles per hour; but it is easy to 
 deduce from it that which would take place at any other velocity, by multiplying by the fourth root of 
 the ratio between the given velocity and the velocity of 20 miles. 
 
 It must, however, be observed, with respect to these determinations, that they are strictly suitable 
 only to boilers constructed in proportions not very different from those used in the experiments ; that 
 is to say, according to what has been explained above, that the heating surface of the fire-box ought 
 not to be under a tenth of the total heating surface of the boiler, and the orifice of the blast-pipe not 
 much larger than we had it in our experiments, according to the adopted practice. Were any notable 
 change made in this respect, were the fuel of an inferior quality, or the engine materially different in 
 construction from what we have described, there would be grounds for a new determination of the 
 vaporization. 
 
 In fine, we will again add, that the numbers obtained above indicate rather the consumption of water 
 of the boiler, than the real vaporization produced ; for we shall presently see, that out of the total water 
 thus expended by the engine, there is a portion which is drawn into the cylinders, mixed with the steam, 
 but without being itself vaporized. Consequently, to obtain the real vaporization of the engine, it will 
 be necessary to take account of this circumstance, as we shall do further on. 
 
 Of the loss of steam which takes place by the safety-valves, during the icork of locomotive engines . — 
 Among locomotive engines there are a great number which are subject to a continual loss of steam by 
 the safety-valves. This effect arises from the engine being designedly constructed with an excess of 
 
LOCOMOTIVE ENGINE. 
 
 261 
 
 power ; that is to say, that according to the production of steam which takes place in its boiler, the 
 engine cftuld draw its regular load at a greater velocity than it is allowed to do. The result is, that tc 
 prevent the engine from acquiring too great a velocity, it becomes necessary partially to close the regu- 
 lator, that is, to diminish the passage of the steam, till no more enters the cylinder than the quantity 
 necessary to produce the desired velocity. Then the surplus accumulating in the boiler, at last raises 
 the safety-valve and escapes iuto the atmosphere. When this loss takes place only on the regula- 
 tor being somewhat closed, it is but a proof, as we have said, of a surplus of power which the engine 
 holds in reserve. But if it takes place more or less under all circumstances, then it depends on the 
 steam-ways being too narrow, and is consequently a defect in the engine ; in either case, however, it is 
 necessary to obtain a valuation of this loss. 
 
 There is yet another case in which engines are subject to a loss of steam by the valves ; but this loss 
 is owing to a different cause from the preceding, and exhibits itself much more abundantly ; it is when 
 the engine ascends a steep acclivity, with an apparently moderate load, or when it ascends a moderate 
 inclination, with a very heavy load. At these moments the valves are always seen to emit an enor 
 mous quantity of steam. The reason is that, as soon as the engine reaches the inclined plane, its load 
 instantly becomes extremely heavy, on account of the surplus of traction required by the gravity on the 
 plane. It has been shown, in effect, that on a plane inclined every ton produces, by gravity alone, 
 a resistance equal to that of 3'7 tons on a level. It happens therefore, at that moment, that the re- 
 sistance of the train may become greater than the actual pressure of the safety-valve. Consequently 
 the steam, instead of flowing by the cylinder, driving back the piston, raises the safety-valve, and 
 escapes into the atmosphere. If then the passage which the steam thus opens for itself were sufficient 
 for its total efflux, no more steam would pass through the cylinder, and the engine would inevita- 
 bly stop. 
 
 Moreover, since, supposing even the steam in the cylinder at the same pressure as in the boiler, which 
 is the most favorable supposition we can make, it still happens that the volume of steam expended by 
 the cylinder is less than the volume of steam generated in the boiler, a part of the water must have 
 been carried from the boiler to the cylinder, in its liquid state ; and the comparison between the quan- 
 tity of water consumed by the boiler and that which, in the state of vapor, corresponds to the velocity 
 of the piston, shows that the quantity of water really converted into steam, is to the total quantity of 
 water consumed, in the ratio of the numbers 
 
 11827 
 
 15641 — ' b ' 
 
 Thus, in this experiment, we see that -24 of the water expended by the boiler was carried into the 
 cylinders without being reduced to steam, or that the real vaporization of the engine was -76 of the total 
 water expended. 
 
 The results which have just been presented above show that the quantity of water carried away with 
 the steam, varies in different engines, and ought to be determined for each separately ; but as in taking 
 the means between the different experiments, that loss is found to amount to -24 of the total vaporiza- 
 tion of the boiler, this proportion may be adopted approximatively for engines that have not been 
 directly submitted to experiment in this respect ; that is to say, in order to have the effective vaporiza- 
 tion of a locomotive, the total vaporization of which its boiler is capable must be first measured ; from 
 the result must be subtracted , if necessary, the loss, either accidental or permanent, which may be observed 
 at the safety-valves, and the remainder must be multiplied by the fraction -76. Thus will be obtained 
 the volume of water which passes into the cylinder, in the real state of steam, and produces the motion 
 of the piston. 
 
 We liave reason then to think, from the different experiments cited above, that with coke for fuel, and 
 with the other circumstances of the work and the construction of the engines, the most advantageous 
 ratio to establish between the total heating surface and that of the fire-box would be nearly that of 10 
 to 1 : since for a less proportion there would be increase in the expenditure of fuel, without increase of 
 vaporization ; and for a greater proportion, on the contrary, there would be reduction in the vaporization 
 of the engine per unit of surface, which would incur the necessity of a larger boiler, and consequently of 
 a greater weight, which it is important to avoid. 
 
 In fine, to arrive at a general conclusion from the experiments which have been made in order to the 
 determination of this question, it appears that, according to the proportion of the fire-box to the total 
 heating surface, the consumption of fuel in locomotive engines varies from 9'2 to 1T3 and 11'7 pounds 
 per cubic foot of total water vaporized : so that it may, on an average, be valued at 10 7 pounds of coke 
 
 per cubic foot of total vaporization, or its equivalent in other fuel. 
 
 Fuel. — To find the quantity of fuel necessary for the engine per ton per mile, the load the engine is 
 to draw must previously be given : in multiplying the given load by the velocity the engine will assume 
 with that load, the product will immediately make known, in tons conveyed one mile per hour, the use- 
 ful effect of the engine. Dividing then the consumption of fuel of the engine per hour by the useful 
 effect produced in the same time, the quotient will give definitively the quantity of fuel which will be 
 consumed by the engine per ton per mile in drawing the given load. 
 
 The principal problems which occur with respect to locomotive engines have reference in the first 
 place to two circumstances, namely: 1. When the engine is already constructed, and the question is to 
 
 determine the effects that it will produce ; 2. When the engine is as yet unbuilt, and the question is to 
 
 determine the proportions it ought to have in order to produce desired effects. At present we consider 
 only the questions relative to the first case. 
 
 When an engine is already constructed, and all its dimensions may be directly measured, the follow 
 ing problems may present themselves: 
 
 1. To determine the velocity the engine will assume with a fixed load ; 
 
 2. To determine the load it will draw at a desired velocity; 
 
“262 
 
 LOCOMOTIVE ENGINE. 
 
 3. To determine the useful effect it will produce at a desired velocity, or with a fixed load. 
 
 And this last problem may itself be expressed under ten different forms — namely, to find successively 
 
 The useful effect of the engine in tons drawn one mile ; 
 
 The useful effect expressed in horse-power ; 
 
 The quantity of fuel necessary per ton per mile ; 
 
 The quantity of water necessary per ton per mile ; 
 
 The useful effect produced per pound of fuel consumed ; 
 
 The useful effect produced per cubic foot of water vaporized ; 
 
 The consumption of fuel which produces one-horse power ; 
 
 The consumption of water which produces one-horse power ; 
 
 The horse-power produced per pound of fuel ; 
 
 The horse-power produced per cubic foot of water vaporized. 
 
 Moreover, as two cases are necessarily to be distinguished in the work of the engines, namely, the 
 case in which they work with a load or velocity indefinite, and that in which they work with the load 
 or velocity which produces the maximum of usef ul effect, there will yet occur in tins respect a new series 
 of questions, namely : 
 
 1. To determine the velocity at which the engine will produce its maximum of useful effect ; 
 
 2. To determine the load corresponding to the production of the maximum of useful effect ; 
 
 3. To determine the maximum of useful effect that the engine can produce. 
 
 And this last problem may be expressed under the ten different forms which we have indicated 
 above. 
 
 Of the velocity of the engine with a given load. — Suppose, in effect, that a load of 50 tons gross, tender 
 included, be drawn up a plane inclined by an engine with 2 cylinders 11 inches hi diameter, stroke 
 of the piston 16 inches, wheels 5 feet, friction 103 pounds, total pressure of the steam in the boiler 65 
 pounds, or effective pressure 50 pounds per square inch, and, finally, vaporizing pjower 60 cubic feet of 
 water per hour, or 1 cubic foot per minute. 
 
 The total resistance opposed by that load to the motion of the piston is 48 pounds per square inch, 
 when the velocity is 20 miles per hour. If, then, we admit that the engine will come near enough to 
 that velocity, for the valuation which we have made of the resistance of the air and the pressure caused 
 by the blast-pipe, in the calculation, not to be very far from the truth, we must conclude that, during 
 the uniform or permanent motion of the engine with that load, the pressure of the steam, during its 
 action in the cylinder, will likewise be 48 pounds per square inch. 
 
 Now, the quantity of water consumed by the boiler amounts to 60 cubic feet of water per hour, and 
 we have shown in treating of the vaporization that out of that mass of water 75-lOOths only, on an av- 
 erage, are really converted into steam, and that the rest is merely carried away with the steam into the 
 cylinders, but in a liquid state. The effective vaporization of the engine is, then, firstly, 
 
 •75 X 60 = 45 cubic feet per hour, or 
 •75 cubic foot per minute. 
 
 This water is first transformed, in the boiler, into steam at the total pressure of 65 pounds per square 
 inch ; but on passing into the cylinders it acquires the pressure of 48 pounds per square inch, and we 
 know that, in this change, the steam remains always at the maximum density for its temperature. Its 
 volume may then be determined by the table, which we have already given, on the volume of the steam 
 formed under different pressures. According to this table, the volume of the steam formed under the 
 total pressure of 48 pounds per square inch, is 573 times that of the water which produced it. Hence 
 the quantity of water effectively vaporized per minute in the boiler, will form, during its passage through 
 the cylinders, a volume of steam expressed by 
 
 573 X ’75 =430 cubic feet. 
 
 On the other hand, the area of each cylinder is 95 square inches, or in square feet that area is repre- 
 sented by '66 square foot; and the stroke of the piston is 16 niches, or T33 foot. Whence the capacity 
 of each cylinder traversed by the piston is 
 
 •88 cubic foot. 
 
 But besides the portion traversed by the piston there still exists, at each end of each cylinder, a vacant 
 space called the clearance of the cylinder, which is necessarily filled with steam at each stroke. The 
 capacity of this vacant space, represented by an equivalent portion of the cylinder, and steam-ways 
 included, is usually l-20th of the part of the cylinder traversed by the piston. The real capacity, there- 
 fore, which is filled with steam at each stroke of the piston, is 
 
 •88 X — '924 cubic foot. 
 
 Consequently the number of strokes of the piston which the engine will give per minute, by reason of 
 its effective vaporization, will necessarily be 
 
 430 
 
 ■ = 46o. 
 
 •924 
 
 Now, each time the wheel makes one revolution the engine gives two strokes of the piston in each of 
 its two cylinders ; and the diameter of the wheel is 5 feet, which makes 1 5‘7 1 feet in circumference. 
 Therefore, at every four strokes of the piston the engine advances 15’7l feet; that is to say, its velocity, 
 in feet per minute, will be 
 
 — X 15-71 = 1822 feet. 
 
 4 
 
 Finally, as one mile contains 5280 feet, and one hour contains 60 minutes, the definitive velocity of tie 
 engine, in miles per hour, will be 
 
LOCOMOTIVE ENGINE. 
 
 20 : 
 
 X 1822 = 20'7l miles. 
 
 5280 
 
 Thus we see that the above vaporization will necessarily produce a velocity of 20'7 miles per hour 
 for the engine ; that is to say, a locomotive engine with the given proportions may, if in good order, and 
 with a well-stocked fire, draw a load of 50 tons gross, tender included, up a plane inclined at the 
 velocity of 20'7 miles per hour. 
 
 With regard to the velocity which we have just obtained, we must add that if the engine suffers be- 
 sides a loss of steam by the safety-valve, which takes place in a great number of locomotive engines, 
 there will then be a corresponding loss on the effective vaporization ; and consequently the definitive 
 velocity of the engine will be reduced in a corresponding proportion. For instance, if the engine 
 be liable to a loss of - 05 of its vaporization in full activity, its definitive velocity, in the case above 
 mentioned, will become 
 
 •95 X 20'71 = 19'67 miles per hour. 
 
 The calculation will be performed in the same manner for every other load and for every other engine. 
 Thus, in general, 
 
 M, Representing the number of tons of the load, tender included ; 
 in, The weight of the engine, in tons ; 
 
 g, The gravity, in pounds, of one ton on the plane the engine has to traverse ; this gravity being null 
 for the case of a horizontal plane ; 
 
 k, The friction of the wagons per ton, expressed in pounds ; 
 v, The velocity of the engine, in miles per hour ; 
 
 u v 2 , The resistance of the air against the train, at the velocity v, resistance expressed in pounds ; 
 p' v, The pressure against the piston, arising from the action of the blast-pipe, expressed in pounds per 
 square foot ; 
 
 F, The friction of the engine, in pounds ; 
 
 6, Its additional friction, measured as a fraction of the resistance ; 
 
 D, The diameter of the propelling wheels of the engine, in feet; 
 d, The diameter of the cylinder, in feet ; 
 
 l, The length of the stroke of the piston, in feet ; 
 
 c, The clearance of the cylinder, represented by an equivalent portion of the stroke of the piston, 
 and consequently in feet ; 
 
 P, The total or absolute pressure of the steam in the boiler, in pounds per square foot ; 
 p, The atmospheric pressure, expressed in pounds per square foot ; finally, 
 
 S, The effective vaporization of the engine, in cubic feet of water per hour, at the velocity known or 
 unknown of the motion ; 
 
 R = (l + ^) [(k±gW±gm + uv i ]^ l + J ^ l + p-{-p'v, 
 
 will be the pressure of the steam per unit of surface in the cylinder. 
 
 On the other hand, if we express by n the relative volume of the steam generated under the pressure 
 R, a relative volume which will be found in the tables given, p. 230, since S is the volume of water 
 vaporized per hour in the engine, it follows that 
 
 will be the corresponding volume of the steam under the pressure R ; that is to say, during its action in 
 the cylinders. 
 
 But, expressing by w the ratio of the circumference to the diameter, the capacity of each cylinder 
 which is traversed by the piston, has for its measure 
 
 indH- 
 
 and the clearance of the cylinder offers, besides, a capacity of 
 
 I ir d ‘ c. 
 
 Therefore the totality of the space filled with steam at each stroke, in each cylinder, has for its 
 expression 
 
 \itd 2 {lffc). 
 
 Consequently the number of strokes of the piston corresponding to the volume of steam expended ^ S, 
 will be n S 
 
 \ it d“ (l -f- c) 
 
 But, while each piston performs 2 strokes, that is, at every expenditure of 4 cylinders-full of steam, 
 the engine advances 1 turn of the wheel, that is to say, a space represented by 
 
 Therefore the velocity of the engine, in feet per hour, will be expressed by the above number of strokes, 
 divided by 4 and multiplied by it D ; that is to say, the velocity will be 
 
 D 
 
 / -j- c 
 
 And finally, as 1 mile contains 5280 feet, the velocity of the engine expressed in miles per hour, will be 
 
 1 D 
 
 528o" d 2 ' l-\-c 
 
 ( 1 ) 
 
 i'his expression will make known the velocity required, on substituting, for each of the letters, the valut 
 suitable to it in the engine considered. 
 
264 
 
 LOCOMOTIVE ENGINE. 
 
 As it has been shown that the relative volume of the steam under the pressure R, may be ex- 
 pressed by 
 
 1 
 
 n + q R 
 
 it is plain that, instead of seeking the relative volume n in the table which we have given, its value may 
 be represented by the expression 
 
 1 
 
 n + yR 
 
 n + y 
 
 1 
 
 ( + <0 [(i-±y)M±ym+M» ! ]^+^+])+y!) j- 
 
 and consequently the preceding expression of the velocity of the engine may equally be written under 
 the form 
 
 i 2 _j_ s 
 
 o-80 q l + c ^^. 3 ) [(£±S , )M±y»i + Mif'] + F + 3 " +.P 
 
 (1 bis) 
 
 Such then will be the general expression of the velocity of the engine, in miles per hour ; an expression 
 in which all is known from measures taken on the engine, even the vaporization S, which results from 
 the extent of heating surface. 
 
 Making use of this formula to find the velocities corresponding to divers loads of the engine, or to 
 divers values of M, attention must be paid never to suppose, for M, a load capable of producing on the 
 piston a resistance greater than the pressure of the steam in the boiler, because it is evident that the 
 resistance would then exceed the power, and the motion could not take place. Nor can M be supposed 
 of a value less than the weight of the tender, which is the minimum load an engine can have to draw. 
 Beyond these two limits the solutions given by the formula would evidently cease to suit the problem. 
 
 Practical formulae for calcxilating the effects of locomotive engines, and examples of their application . — 
 We have hitherto presented the formula proper for calculating the effects of the engines, under a 
 form completely algebraical, that is to say, leaving in them all the quantities represented by letters, 
 without excepting the constant quantities whose values have been already determined in former pages. 
 But we now purpose to reduce these formula to their most simple practical form ; in order to effect 
 which, it will be proper to replace in them, as far as may be, the letters, by the numerical values which 
 they represent. 
 
 The letters which have a constant value in all cases and for all the' engines are — 
 
 Friction of the wagons, which we have found equal to 6 lbs. per ton ; 
 
 p, Atmospheric pressure, the value of'which is 2118 lbs. per square foot; 
 
 n, Constant quantity relative to the volume of the steam, its value being '0001421, when the pressure 
 is measured in pounds per square foot ; 
 
 q, Factor relative to the volume of the steam, equal to '00000028 when the pressure is expressed in 
 
 pounds per square foot ; 
 
 c, Clearance of the cylinder, which may be taken generally at — of the useful stroke of the piston, which 
 
 gives 
 
 l _ 20 
 1+c-Ti 
 
 These values being constant for all engines, may be introduced permanently into the equations. Sub- 
 stituting them therefore for the respective letters, and effecting the calculation as much as possible, we 
 obtain the following formulae, which are quite prepared for practical applications. 
 
 In order to avoid recurring to another page of the w T ork, we will first repeat here the signification oi 
 all the letters which subsist in these formute. 
 
 M, Load of the engine, in tons gross, tender included ; 
 m, Weight of the engine, in tons ; 
 
 C, Weight of the tender, in tons ; 
 
 < 7 , Gravity, in pounds, of 1 ton placed on the inclined plane to be traversed by the engine. If the in- 
 1 2240 
 
 clination of the plane be — > that gravity*(vill have for its value, in pounds, ; and if the plane 
 
 be horizontal, the gravity will be equal to zero; 
 v, Velocity of the engine, expressed in miles per hour; 
 
 « jj 2 , Resistance of the air against the train, at the velocity v, a resistance expressed in pounds ; 
 p' v, Pressure owing to the blast-pipe, expressed in pounds per square foot ; 
 
 F, Friction of the engine, in pounds ; 
 
 <?, Additional friction of the engine, measured as a fraction of the resistance, namely: T4 for engines 
 with uncoupled wheels, and '22 for those with coupled wheels; 
 
 D, Diameter of the propelling wheels, in feet ; 
 d. Diameter of the cylinder, in feet ; 
 
 i. Stroke of the piston, in feet ; 
 
 P, Total or absolute pressure of the steam in the boiler, in pounds per square foot ; 
 
 S, Effective vaporization of the engine, in cubic feet of water, per hour. It varies according to the 
 engines, but may, on an average, be valued at '75 of the total or gross vaporization, when there 
 is no blowing of steam at the valves; 
 
 S', Total vaporization of the boiler, at the velocity of the motion, in cubic feet of water per hour 1 
 
 N, Consumption of coke in the fire-box, in pounds per hour. 
 
LOCOMOTIVE ENGINE. 
 
 265 
 
 PRACTICAL FORMULAS FOR CALCULATING THE EFFECTS OF LOCOMOTIVE ENGINES. 
 
 General case. 
 
 784 S 
 
 v — fffl 
 
 (1 + i) [( 6 ± 5 ')M±i”« + “i' 2 ] + F + — (2736 +p'v) 
 
 Velocity of tlie engine, in miles per hour. 
 
 M= p5)W)t ,84 » _ T (a,3,! +' > '’)- F ]-«S5 ( “'’ ±! '” ) = 
 
 Load of the engine, in tons gross, tender included. 
 
 u. E =M» = 
 
 Useful effect, in tons gross, drawn 1 mile per hour, tender included. 
 
 u ‘ KinHP ~ 62-5 ~ 
 
 Useful effect, in horse-power. 
 
 N 
 
 Q. co. pr. t. pr. M = vj jr — 
 
 1 r My — (J v 
 
 Quantity of coke in pounds, per ton gross drawn 1 mile, tender not included. 
 
 S' 
 
 Q. wa. pr. t. pr. m = rj — = 
 
 1 r My — Cy 
 
 Quantity of water, in cubic feet, per ton gross drawn 1 mile, tender not included. 
 
 My 
 
 u. E. 1 lb. co = — = 
 
 N 
 
 Useful effect produced per pound of coke, in tons gross drawn 1 mile, tender included. 
 
 _ My 
 
 u. E. 1 ft. wa = -t— = 
 
 Jo 
 
 Useful effect produced per cubic foot of total vaporization, in tons gross drawn 1 mile, tender ircluded 
 
 Q. co. fr. 1HP = < ^^ = 
 
 Mv 
 
 Quantity of coke in pounds, w hich produces the effect of 1 horse. 
 
 Q. wa. fr. 1 HP = 
 
 Mv 
 
 Quantity of water, in cubic feet, which produces the effect of 1 horse. 
 
 u. E. 1 lb. co. in H P = — = 
 
 62o N 
 
 Useful effect, in horse-power, produced per pound of coke. 
 
 u. E. 1 ft. wa. in H P = - M V , = 
 
 62'5 S’ 
 
 Useful effect, in horse-power, produced per cubic foot of total vaporization. 
 
 Case of maximum useful effect. 
 
 1-804 D S _ 
 
 V ~ 1-421+ -0023 P 7 + 
 
 Velocity of maximum useful effect, in miles per hour. 
 
 M ' = (i + s)[Lg)i > ( p - 2118 -P' ^ ^ m ) = 
 
 Maximum load of the engine, in tons gross, tender included. 
 
 M. u. E =Wv’ = 
 
 Maximum useful effect, in tons gross drawn 1 mile per hour, tender included. 
 
 That there may be no misunderstanding as to the manner of expressing the divers quantities contained 
 in the formula!, nor on the manner of performing the calculation, we will here give an example or tw r o 
 with some detail. 
 
 Suppose a locomotive of 65 cubic feet of total vaporization, at the velocity of 20 miles per hour ; 
 with cylinders 11 inches or -917 foot in diameter, stroke of the piston 16 inches or P33 foot, wheels 5 
 feet in diameter, not coupled, friction 103 lbs., weight 8 tons, blast-pipe 2'33 inches in diameter, total or 
 absolute pressure in the boiler 65 lbs. per square inch, and consumption of coke per hour 598 lbs. Sup- 
 pose this engine employed on a level railway, of about 5 feet of width of way, and let it be required tc 
 
266 
 
 LOCOMOTIVE ENGINE. 
 
 know what velocity it will attain with a train of 10 wagons weighing 56 tons, tender included, which 
 is the same as 5t) tons without tender. 
 
 1st. As the motion takes place on a horizontal plane, we have <7 = 0; and since the wheels of the 
 engine are not coupled, we have <3 =-14 ==■}. Moreover, from the ratio which we have found between 
 the total and the effective vaporization of the engine, the value of the latter, at 20 miles per hour, is 
 S = -75 X65 = 48-75 cubic feet of water per hour ; 
 
 *nd in fine, from the proportions of the engine, we have 
 
 <IH — 2 1-33 
 
 — = •917 X— = '2237. 
 U 5 
 
 This done, to find what velocity the engine will acquire in drawing the train of 06 tons, we will first 
 suppose that it may be, approximative^, 23 miles per hour, and we shall then have, for the pressure in 
 the blast-pipe, 4 lbs. per square inch, or p' v — 576 lbs. per square foot. As the effective surface pre- 
 sented to the shock of the air, valued according to the mode already explained, is S = 70 — f- 10X12 = 190 
 square feet, the resistance of the air at the velocity of 23 miles per hour, will be u v 2 = 270. 
 
 Thus the value of v, taken without supposing that the vaporization changes with the velocity, will be 
 
 784X48-75 n)00 
 
 v = = 24*88. 
 
 1-14(6X56 + 270) + 103 + *2237 (2736 + 576) 
 
 This first essay of calculation gives then 24-88 miles per hour, for the velocity of the engine, and we 
 conclude from it that the two terms u v 2 and p' v which we have calculated on the supposition of v = 23, 
 have not been valued in a manner sufficiently exact, but that the true velocity is comprised between 
 24'88 and 23 miles. 
 
 Trial then might be made of v = 24, and this value would be found to satisfy the problem, when the 
 variation which the vaporization undergoes with the velocity of the motion is neglected. Thus approx- 
 imatively we might hold to this result ; but if it be desired to calculate with greater accuracy, it will be 
 proper to introduce the increase of vaporization due to the velocity. 
 
 For this purpose, as the increase of vaporization will have the effect of increasing the result of the 
 calculation, we will try a number greater than 24, as v = 25, for instance. Supposing then this datum 
 for the valuation of the variable quantities, we shall have 
 
 S = 5T55, 
 p' v = 630, 
 u i' 2 = 3 1 9 ; 
 
 and resolving the equation with these values we find 
 
 v = 25-19. 
 
 Consequently, in fine, taking a mean between 25 and 25-19, we have, for the definitive velocity sought, 
 
 v = 25'10 miles per hour. 
 
 Such then will be the velocity which the engine will assume, when drawing on a level a train of 56 
 tons, tender included. 
 
 2d. To continue this example of the application of the formulae, let it be required to find what will be 
 the velocity of the maximum useful effect of the engine. 
 
 In order to effect this, we will replace in the equation proper to that problem, the pressure P in the 
 boiler by its value P = 65 X 144 = 9360 lbs. per square foot ; and supposing first that the vaporization 
 of the engine will undergo no change notwithstanding the reduction of velocity, we obtain the result 
 
 , 1-804 X 48-75 1 
 
 v'= ; = 17T3. 
 
 1-421 + -0023 X 9360 '2237 
 
 This would then be the velocity sought, if the vaporization of the engine were invariable ; but as the 
 diminution of velocity will lower the vaporization, which is such as we have supposed it, only at the 
 velocity of 20 miles per hour, we will try whether the velocity of 16 miles will suit the formula. Then 
 the effective vaporization of the engine, reduced in the proportion of the fourth roots of the velocities, 
 will become 46-10 cubic feet of water per hour, and the formula resolved according to this supposition, 
 will give 
 
 v’ = 16'20 miles per hour. 
 
 This is therefore the velocity suitable to the production of the maximum useful effect required. 
 
 3d. In fine, to obtain the load corresponding to the maximum of useful effect, we recur to the proper 
 equation, which is 
 
 , r , dH 1 , , F W 2 
 
 M' = — • . (P — 2118— p’v’) — 
 
 D 6 (1 + <S) ' 
 
 6 (1 +< 5 ) 
 
 and first calculating in this all the terms, except the last, we have as a result 208'46. 
 
 It remains then to subtract from this number the value of — ■ V — > to conclude from it definitively the 
 
 11 
 
 required value of the load. As the value of the term — depends on the number of carriages in the 
 
 train, which will itself be known only by the definitive solution of the problem, we will again in this 
 place follow the method of approximations. Supposing the load to be of about 1 60 tons, the train will 
 consist of 31 carriages besides the tender ; thus the effective surface offered to the shock of the air, will be 
 
 2 = 70 + 33 X 10 = 400 square feet. 
 
LOCOMOTIVE ENGINE. 
 
 267 
 
 Consequently the resistance of the air, at the velocity found, of 16-20 miles per hour, will he u v' 2 = 28? 
 lbs., which gives 
 
 substituting then this valuation in the formula, we obtain the result 
 
 M' = 208-46 — 47-00 = 161-46. 
 
 Consequently the load of 161-6 tons, forming a train of 31 carriages, besides the tender, will be tha 
 maximum load required. 
 
 4th. In fine, if it be desired to know the maximum velocity the engine is capable of attaining, when 
 followed by its tender only, and without drawing any train, the proceeding will be as in the first case ; 
 but supposing the load to be of 6 tons only, and taking account of the increase of vaporization, accord- 
 ing to the velocity, the result will be 
 
 v = 35 03 miles per hour. 
 
 In this last case, the useful effect of the engine, tender not included , will be null. 
 
 From these detailed examples is seen how the calculation is to be performed in all the cases ; but it 
 must be remarked, that with the use of logarithms, these different trials present no sort of difficulty, and 
 that those who have once got the habit of these researches, guess immediately and at a glance, what 
 numbers they ought to employ in the approximations, so that the apparent length of the calculation 
 entirely disappears. 
 
 Collecting the results which we have just obtained, calculating moreover the useful effect of the 
 engine, and expressing it under the different forms already indicated, we form the following Table : 
 
 Effects of a locomotive of 65 cubic feet of vaporization , with a load of 56 tons gross, on a level, tender 
 
 included. 
 
 M = 56 tons gross, tender included, (10 carriag-js and the tender ;) 
 
 v = 2510 miles per hour; 
 
 u. E = 141 1 tons gross drawn 1 mile per hour, tender included ; 
 
 u. E. in H P =23 horses ; 
 
 Q. co. pr. t. pr. m = -47 lb. per ton gross per mile, tender not included ; 
 
 Q. wa. pr. t. pr. m. ... = -052 cubic foot per ton gross per mile, tender not. included ; 
 
 u. E. 1 lb. co = 2-36 tons gross drawn 1 mile, tender included ; 
 
 u. E. 1 ft, wa = 2T70 tons gross drawn 1 mile, tender included- 
 
 Q. co. fr. 1 HP = 26-50 lbs. ; 
 
 Q. wa. fr. 1 H P = 2-880 cubic feet ; 
 
 u. E. 1 lb. co. in H P. = -038 horse ; 
 u. E. 1 ft. wa. in H P. = -347 horse. 
 
 Maxima effects of the same engine. 
 
 M' = 161-5 tons gross, tender included, (31 carriages and tender;) 
 
 v‘ = 16-20 miles per hour ; 
 
 u. E =2616 tons gross drawn 1 mile per hour, tender included ; 
 
 u. E. in H P =42 horses ; 
 
 Q. co. pr. t. pr. m. ... = -24 lb. per ton gross per mile, tender not included ; 
 
 Q. wa. pr. t. pr. m. ... = -026 cubic foot per ton gross per mile, tender not included ; 
 
 u. E. 1 lb. co = 4'38 tons gross drawn 1 mile, tender included ; 
 
 u. E. 1 ft. wa = 40-25 tons gross drawn 1 mile, tender included ; 
 
 Q. co. fr. 1 H P = 14-29 lbs. 
 
 Q. wa. fr. 1 HP = 1-553 cubic foot; 
 
 u. E. 1 lb. co. in H P. = -070 horse ; 
 u. E. 1 ft. wa. in H P. = -644 horse. 
 
 To give a second example of this calculation, we will suppose the railway to have 7 feet of width of 
 way, and seek what will be the velocity of the engines of medium force, in use on such a line, under 
 the same circumstances as we have just examined relatively to a railway of about 5 feet of width of way. 
 
 We will suppose then a locomotive of 120 cubic feet of vaporization, at the velocity of 25 miles per 
 hour, with the following proportions : cylinders, 14 inches or 117 foot in diameter ; stroke of the piston, 
 16 inches or 1-33 foot; wheels, 8 feet in diameter, not coupled; weight, 18 tons; friction, 270 lbs.; 
 blast-pipe, 3-14 inches in diameter ; total or absolute pressure in the boiler, 80 lbs. per square inch ; and 
 consumption of coke in the same time, 1050 lbs. or 8"75 lbs. per cubic foot of water vaporized. More- 
 over, by reason of the width of the way, we will take the surface of the largest wagon of the train at 
 100 square feet, the average surface of a wagon at 56 square feet, and the weight of the tender at 10 
 tons. 
 
 . Seeking then by the same calculation as before, what effects this engine is capable of producing, first 
 m drawing a train of 60 tons gross, tender included, which makes 50 tons without the tender and after 
 wards in drawing its maximum load, we obtain the following results : 
 
268 
 
 LOCOMOTIVE ENGINE. 
 
 Effects of a locomotive of 120 cubic feet of vaporization, with a load of 60 tons gross, tender included 
 
 M = 60 tons gross, tender included, (7 carriages and the tender ;) 
 
 v = 34'75 miles per hour; 
 
 u. E = 2085 tons gross drawn 1 mile per hour, tender included ; 
 
 u. E. in H P =33 horses; 
 
 Q. co. pr. t. pr. m. ... = '60 lb. per ton gross per mile, tender not included ; 
 
 Q. wa. pr. t. pr. m. ... = -069 cubic foot per ton gross per mile, tender not included ; 
 
 u. E. 1 lb. co = 1-99 ton gross drawn 1 mile, tender included ; 
 
 u. E. 1 ft. wa = 17 38 tons gross drawn 1 mile, tender included; 
 
 Q. co. fr. 1 H P = 31'48 lbs. ; 
 
 Q. wa. fr. 1 H P = 3 597 cubic feet; 
 
 u. E. 1 lb. co. in H P. = '032 horse ; 
 u. E. 1 ft. wa. in H P. = -278 horse. 
 
 Maxima effects of the same engine. 
 
 M' = 147 tons gross, tender included, (20 carriages and the tender 
 
 v' = 25 55 miles per hour; 
 
 u. E = 3756 tons gross drawn 1 mile per hour, tender included ; 
 
 u. E. in H P =60 horses ; 
 
 Q. co. pr. t. pr. m. ... = - 30 lb. per ton gross per mile, tender not included ; 
 
 Q. wa. pr. t. pr. m. ... = -034 cubic foot per ton gross per mile, tender not included; 
 
 u. E. 1 lb. co = 3'58 tons gross drawn 1 mile, tender included ; 
 
 u. E. 1 ft. wa = 31'30 tons gross drawn 1 mile, tender included; 
 
 Q. co. fr. 1 II P = 17'47 lbs. ; 
 
 Q. wa. fr. 1 H P = 1997 cubic foot; 
 
 u. E. 1 lb. co. in H P. = -057 horse ; 
 u. E. 1 ft. wa. in H P. = -501 horse. 
 
 The velocity of the same engine, drawing its tender alone, would be 43'28 miles per hour ; which 
 would be the maximum of velocity that this engine could attain. 
 
 It is visible, in these examples, that the above formulae present no difficulty, and that it is merely 
 necessary to preserve in them the homogeneity of the measures employed. 
 
 Practical formulae, to determine the proportions of locomotive engines, according to given conditions.— 
 We will here give, in their numerical form, all the formulae which are essential for determining the pro- 
 portions of the engines, according to given conditions. For the signification of the signs employed, wi 
 refer to page 243 of this volume. 
 
 PRACTICAL FORMULA TO DETERMINE THE PROPORTIONS OF LOCOMOTIVE ENGINES, NECESSARY TO PRODUCE 
 
 GIVEN EFFECTS. 
 
 . G +l)v 
 784 
 
 [(6 ± g) M db g rn + u v 1 + — ^ ^ (2736 + p' p)”J = 
 
 ^ [lira* 7 - 1 (6 ± g) M T V m - 11 u *' - IT^] =■ 
 
 Total vaporization of the boiler, in cubic feet of water per hour. 
 
 d==°._i±A 
 
 l 2736 + P 
 Square of the diameter of the cylinder, in feet. 
 
 , D 1 +5 r ^ S ^ , FT 
 
 d? 2736 +p'v Ll + a v v y 1-HJ 
 
 Stroke of the piston, in feet. 
 
 D: 
 
 cPl 
 
 2736 + />' v 
 
 '1 + 6 784 S 
 
 Diameter of the wheel, in feet. 
 
 1 -J- <5 v 
 
 — (6 m - 
 
 i + a 
 
 S = -i-.^.v (618 + P) = 
 
 784 D 
 
 Total vaporization of the boiler, in cubic feet of water per hour. 
 
 P = (1 + i ) jr / [ ( 6±flr) M ±flr« + «* ,I + j-^J+2118+pV. 
 
 Total or absolute pressure of the steam in the boiler, in pounds per square foot. 
 
 P =784 — .-, — 618 = 
 d 3 1 v' 
 
 Total or absolute pressure of the steam in the boiler, in pounds per square foot 
 
 1 
 
 d 2 = 784?.^. 
 
 Square of the diameter of the cylinder, in feet. 
 
 I v' 618 + P 
 
LOCOMOTIVE ENGINE. 
 
 269 
 
 , =m E s i _ 
 
 784 cf 2 V*618 + P 
 
 Stroke of the piston, in feet 
 
 d= 4-^-I'( 618 + f )= 
 
 Diameter of the wheel, in feet. 
 
 r) (6 ±<7)M ' ±gm + uv rl -f 
 
 d * = 7 ' P — 2118— p'v' 
 
 Square of the diameter of the cylinder, in feet. 
 
 D (6±'7)M ' ±gm + uv'* + 
 
 1 = (1 + i) • P — 2118 — pV 
 
 Stroke of the piston, in feet. 
 
 F 
 
 r+i _ 
 
 F 
 
 1+1 
 
 (PI P — 2118 — p’v' 
 
 (6 ±<j)W ±gm + uv n + — - 
 
 1 T o 
 
 Diameter of the wheel, in feet. 
 
 Of adhesion . — It has been observed, in the description of the engine, that the effort of the steam 
 being applied to the wheel, the engine is precisely in the case of a carriage which is made to advance 
 by pushing at the spokes. Tims, as in this action the only fulcrum of the mover is the adhesion of the 
 wheel to the rails, if that adhesion were insufficient, the force of the steam would indeed make the 
 wheels turn ; but these, sliding on the rails instead of adhering to them, would turn without advancing, 
 and the engine would remain on the same spot. 
 
 The heavier the train to be drawn, the more force the engine must employ, and the more resistance 
 it must consequently meet with at the point on which it strains to effect the motion. It might then be 
 feared that with trains of considerable weight, the engines would be unable to advance ; not that force 
 would be wanting in the mover itself, but in the fulcrum of the mover. 
 
 Adhesion being indispensable to the creation of the progressive motion, two conditions are requisite 
 for an engine to be capable of drawing a given load : 1st, the dimensions and proportions of the engine 
 and its boiler must enable it to produce, by means of the steam, the necessary pressure on the piston, 
 which constitutes the force apjffied by the engine ; and 2d, the weight of the engine must be such as 
 to cause a sufficient adhesion to the rails. These two conditions of force and weight should accord to- 
 gether; for, were there a great force of steam and a slight adhesion, the latter would limit the effect of 
 the engine, and steam would be lost; and were there too much adhesive weight for the power of the 
 engine, that weight would, during the motion, become a useless burden, since the limit of the load would 
 then be marked by the pressure of the steam. 
 
 It is necessary therefore, after having determined the dimensions of the engines from the conditions 
 which they are to fulfil, as has been done in the preceding pages, to seek what ought to be their weight 
 so as to enable them to draw the greatest load intended to be imposed on them during their work. 
 The enormous weight now given to locomotive engines, generally causes this condition to be fulfilled of 
 itself. Six-wheel engines however require, in this respect, more attention than four-wheel engines, be- 
 cause it often happens, on an uneven railway, that a six-wheel engine is wholly supported on its four 
 extreme wheels, whereas the middle ones, which are the propelling wheels, being accidentally situated 
 immediately above a low part of the railway, scarcely touch the rail, and therefore have but a slight 
 adhesion. In the best state of the rails the adhesion which is the limit of the traction of an engine, may 
 be taken at j ; of the weight on the driver, and it is never less than in the worst state of the rails, 
 when they are greasy and dirty from the effect of wet weather. 
 
 For the preceding calculations and formula} W’e are indebted to M. Pambour, whose works on the 
 steam-engine, both locomotive and stationary, should be in the hands of every engineer and machinist, 
 and to which we refer for a more complete elucidation of the laws which govern the motion of this won- 
 derful machine. 
 
 Locomotive engine and tender . — The example which we have chosen for detailed illustration is the 
 form of locomotive engine and tender at present constructed by Messrs. Hawthorn, of Newcastle, Eng- 
 land, a firm whose success and extensive employment in this branch of the trade is a sufficient guarantee 
 for the excellence of their arrangements. In these figures are embodied all the most recent improve- 
 ments which Messrs. Hawthorn have introduced into their engine, including their patent auxiliary ex- 
 pansion-frame, and the mechanism by which it is moved. 
 
 The engine is made, according to the method generally adopted by Messrs. Hawthorn, with a cranked 
 axle and outside bearings ; it is furnished with six wheels, (designated a six-wheeled engine ;) the driv- 
 ing and fore wheels, which are five feet in diameter, are coupled together, and the hind-wheels, three 
 feet diameter, are placed immediately below the fire-box. By this arrangement the greatest safety is 
 insured, and particularly at high speeds ; the same amount of stability being given to the engine as if 
 the hind-wheels were placed behind the fire-box, with this additional advantage, that the length of 
 coupling between the wheels may by the present disposition, be regulated to any convenient distance. 
 An engine of this description will be found exceedingly useful for general purposes, being adapted both 
 for merchandise and for mixed or passenger trains at ordinary speeds ; while for express or special 
 
•270 
 
 LOCOMOTIVE ENGINE. 
 
 trains, where a high rate of speed is required, railway travelling would be rendered comparatively safe 
 by employing engines specially made and adapted f<* such purposes. J 
 
 Enumeration of the figures— Fig. 2601, a longitudinal elevation of the locomotive engine 
 rig. 2602, a general plan of the same. ° 
 
 Fig. 2603, a longitudinal elevation of the tender, showing the mode of its connection with tile 
 engine. 
 
 Fig. 2604, a general plan of the tender, in which are seen the cocks for regulating the supply of wates 
 to the boiler, and the hand-wheel for working the brake apparatus. 
 
 The following four figures are sectional views. 
 
LOCOMOTIVE ENGINE. 
 
 271 
 
 Fig. 2605, a longitudinal section of the engine, showing the internal arrangements of the boiler, and 
 the working parts of the engine. 
 
 Fig. 2606, a sectional plan of the engine, with the cylindrical part of the boiler removed, for the 
 purpose of exhibiting the general arrangement of the working parts, and the construction of the 
 fire-box. 
 
 Fig. 2607, a longitudinal section of the tender. 
 
 Fig. 2608, a plan of the tender with the tank removed, showing the construction of the framing, drag- 
 snrinP, brake-geer, &c. 
 
 The following figures represent end elevations and transverse sections of the engine 
 Fig. 2609, an elevation of the engine as seen at the fire-box end. 
 
 Fig. 2610, a transverse section through the fire-box. 
 
 Fig. 2611, an elevation of the engine as seen at the smoke-box end. 
 
 • a f ran sverse section through the smoke-box. In this view the cylinder to the right is sec 
 
 tinned through the steam-passage, while that to the right is supposed to be cut through the discharge 
 port and blast-pipe. 
 
272 
 
 LOCOMOTIVE ENGINE. 
 
 The following figures represent detailed views, drawn to a larger scale, of such parts of the engine 
 and tender as could not be fully shown in combination : 
 
 Fig. 2613, a transverse section of the steam regulator and chest; Fig. 2614, a longitudinal section of 
 the same. 
 
 Fig. 2616, a plan of the piston, with the cover removed to show the packing. 
 
 Fig. 2616, a section of the piston through the lines 12 3. 
 
 Fig. 2617, a plan of the same, complete, with the cover and guards. 
 
 Fig. 2618, a plan of the piston-rod cross-head, with slide-blocks and projecting arm for workmg the 
 feed-pump. 
 
 Fig. 2619, a side view of the same. 
 
 Fig. 2620, an end view of the same. 
 
 Fig. 2621, an elevation of the backward eccentric. 
 
 Fig. 2622, a plan of the same, showing the stud for working the espansion-geer. 
 
 Fig. 2623, a side view of the reversing or coupling link. 
 
 Fig. 2624, an edge view of the same, showing the stud by which the valve is shifted into forward 
 er back geer. 
 
 Fig. 2625, an elevation of the front end of the eccentric-rod. 
 
 Fig. 2626, a plan of the same. 
 
 Fig. 2627, a longitudinal section of the feed pump, with the plunger, valves, <fcc. 
 
 Fig. 262S, an end view of the same. 
 
LOCOMOTIVE ENGINE. 
 
 273 
 
 Fig. 2629; a plan of the double safety-valve, with the seat ; Fig. 2630, a longitudinal section n( 
 
 the same. _ . 
 
 Fig. 2631, an edge view of the driving-wheel, half in section, to show the mode of faxing the arms, 
 tyre, (fee. In this view is also given part of the cranked axle, to show the lelative positions of the cianl, 
 wheel, bearing, die. 
 
 261 IS, 
 
 Fig. 2632, a transverse section of the driving-wheel axle-box, and of part of the outer spring Fig 
 2633, a longitudinal section of the same. 
 
 Fig. 2634, a section of the suspending link for adjusting the weight of the engine on the springs • Fig 
 2635, a side elevation of the same. 
 
 2609. 2610. 2611. 
 
 Stora'Affeigr 
 
 Fig. 2636, a general elevation of the tender brake-geer; Fig. 2637, a plan of the brake-lever and 
 oothed sector ; Fig. 2638, the screw and link-nut for the tender brake. 
 
 Description of the engine. — The fire-box . — The first part of the engine which claims our attention is 
 the fire-box. The form of fire-box which Messrs. Hawthorn have adopted is clearly shown in the end 
 elevation, Fig. 2609, aud transverse section, Fig. 2610. It consists of two parts : the external fire-box A, 
 which in reality forms part of the boiler, being filled with water to about fifteen inches from the top ; 
 and the internal fire-box B, placed within the other, and which contains the fuel for generating steam. 
 The internal fire-box is made of copper, and tapered slightly towards the top, for the purpose of allow- 
 ing the globules of steam which are formed on its sides to ascend more freely. To resist the downward 
 pressure of the steam, the roof is strengthened by the strong malleable-iron stays C C bolted across, and 
 having a bearing against its sides, wlule both external and internal fire-boxes are secured against the 
 lateral strain by having numerous iron stay-bolts aaa screwed through both boxes, and riveted at each 
 end. The fire-door b affords access to the internal fire-box for the admission of coke. It is of an oval 
 form, and the latch is provided with a chain for the greater convenience of opening and shutting. The 
 space between the two fire-boxes at that part where the fire-door is situated is filled by an oval-shaped 
 frame, securely riveted through both, and the fire-door itself is furnished with a plate of iron riveted to 
 the inside at some little distance from it, to save it from warping by the intensity of the heat within. 
 The fire-bars cc distinctly shown in the section Fig. 2605, and in the plan Fig. 2606, are ranged parallel 
 Vol. II — 18 
 
274 
 
 LOCOMOTIVE ENGINE. 
 
 to each other on a wrought-iron frame fixed to the under side of the fire-box, and a portion of them 
 marked d in the plan, is so arranged as to admit of their falling at one end on the removal of the pin 
 which supports them. In this case the burning fuel drops into the ash-box D fixed below to receive it, 
 and the combustion almost immediately ceases. 
 
 The boiler. — As before remarked, the external fire-box A forms part of the boiler, communicating 
 freely with it, and being, like it, filled with water to the proper height when the engine is in operation. 
 The boiler, properly so called, is marked E in the figures, and in the specimen now under notice consists 
 of a cylinder 11 feet 6 inches in length, and 3 feet 6§ inches in diameter outside. It is traversed 
 throughout its length by 107 brass tubes eec, 2J inches outside diameter, of No. 13 and 14 wire gage. 
 
 2612. 2614. 
 
 These tubes are inserted into the front plate of the internal fire-box, (called the tube-plate ,) which is 
 made of a sheet of copper considerably thicker than the other plates of which the fire-box is composed, 
 so as to afford a better bearing for the fixing of the tubes. At the front extremity of the boiler, they 
 pass through a similar plate of iron, which forms the partition between the boiler and the smoke-box 
 Into these plates the tubes are secured at both ends by riveting, and subsequently by strong steel fer- 
 rules accurately turned, and driven firmly into the interior of the tubes, so as to render them perfectly 
 tight and free from leakage. The cylindrical form of the boiler renders lateral staying unnecessary, and 
 the tubes themselves, at that part where they are situated, secure it against the pressure in a longitu- 
 dinal direction ; but for further safety, three strong malleable-iron stay-bolts fff traverse the whole 
 length of the boiler, and are secured to it by round pins passing through brackets riveted to the front 
 tube-plate, and to the back plate of the external fire-box. The whole boiler is covered externally with 
 a coating of thick felt and with strips of wood, called the lagging, or clcading, to prevent the radiation 
 of heat, as well as to give greater symmetry of appearance. 
 
 2619. 
 
 2624. 2623. 
 
 The smoke-b'ox . — The tubes eee all open into that part of the boiler called the smoke-box F, the pur- 
 pose of which is to collect the gases evolved by the combustion of the fuel, and to transmit them through 
 the chimney G into the air. In this compartment of the boiler are also placed the steam cylinders, and 
 other very important parts of the engine, to be hereafter described. The front plate of the smoke-box 
 is furnished with large folding-doors g g , fitted air-tight to it, and provided with a handle, by which both 
 doors are simultaneously shut and opened. These doors, which are distinctly shown in the end eleva- 
 tion, Fig. 2611, and in the section, Fig. 2605, serve to afford access for the insertion and cleaning of the 
 tubes, as well as for the examination and repair of the parts of the engine referred to above. 
 
 The safety-valves and boiler mountings . — Although the efficient working of the engine requires that 
 the boiler be capable of generating steam of a high elastic force, it is yet essential to safety that the 
 uteam pressure be confined within certain limits. In order to insure this, the boiler is provided with 
 
LOCOMOTIVE ENGINE. 
 
 I 
 
 275 
 
 two safety-valves, li and i, both placed in one chest, (Fig. 2629,) fixed on the summit of the external fire- 
 box, and surrounded by a polished brass chimney H, of a form symmetrical with that of the large chim- 
 ney Gr. One of these valves, marked i, which is of the kind called the lever safety-valve, can he regu- 
 lated to any required degree of pressure by the engine-driver, being furnished with a spring-balance, by 
 which the amount of pressure is distinctly indicated. The other safety-valve h is inaccessible, and is 
 loaded by a spiral spring and screws, to such a pressure as may be considered safe, yet higher than the 
 engine is expected, under ordinary circumstances, to require. 
 
 To indicate the height at which the water stands in the boiler, and to enable the driver to keep it 
 always at its proper level, a set of gage-cocks and glass tube j, communicating with the water inside, 
 are fixed at a convenient situation near the foot-plate. A graduated scale is fixed behind the glass 
 tube, and the required level may thus be maintained with considerable accuracy. 
 
 As a precaution against accidents, and to give notice of the approach of the engine, a steam whistle 
 k is attached to the top of the fire-box, and communicates with the steam within by a short pipe, pro- 
 vided with a stop-cock. The internal construction of the whistle is such, that when the stop-cock is 
 opened, the steam rushing out with great force encounters the sharp edges of a species of inverted cup, 
 thereby emitting a shrill and very loud noise, which can be heard at the distance of several miles. 
 
 2629. 2632. 2635. 
 
 Behtid, and at the lowest extremity of the fire-box, is situated the blow-off cock l, by which the boiler 
 may be emptied of water when required ; and, for the purpose of cleansing it of the accumulation of 
 sediment which is constantly being formed in it when the engine is in operation, it is provided with 
 mud-holes both at fire-box and smoke-box ends. These mud-holes, which are shown in Figs. 2609 i nd 
 
t 
 
 27 G 
 
 LOCOMOTIVE ENGINE. 
 
 2612, are secured -when the engine is at work, by covers or doors bearing against the inside of the boiler 
 and fixed each by a single bolt passing through a strong wrought-iron bridge bearing against the outside 
 The steam-pipes and regulator-valve . — The steam-chest or receiver I rises from the centre of tha 
 cylindrical part of the boiler, and is carried to a considerable height above it, in order that the mouth 
 of the steam-pipe J, which opens into it, may be removed to as great a height as can conveniently be 
 obtained, from the surface of the water in the boiler. The object of thus raising the open orifice of the 
 steam-pipe is to prevent priming, that is, the ascent of water along with the steam, and its consequent 
 flow through the steam-pipe into the cylinders, where its presence in any considerable quantity wouid 
 produce the most serious inconveniences, besides the danger to which the boiler would be exposed by 
 its rapid abstraction. As a further precaution against priming, Messrs. Hawthorn make use of a simple 
 but very ingenious contrivance. This consists of a species of inverted cone m, Fig. 2005, made of sheet- 
 iron, and riveted to the interior of the steam-chest, with an aperture in the centre just wide enough tc 
 allow the free ascent of the steam between it and the steam-pipe, which passes through it. The water 
 in the boiler tends to prime chiefly where there is a surface of metal to which it may adhere ; conse- 
 quently, when, in rising up the sides of the steam-chest, it encounters the inverted cone m , its course is 
 diverted downwards and towards the centre, where being unsupported it falls back into the boiler. 
 Should any priming occur round the sides of the steam-pipe itself, the water is, in a somewhat analogous 
 way, diverted by the bell-shaped mouth of the pipe, and returned into the boiler. The steam-receiver 
 is surrounded by a polished brass dome, which, besides being highly ornamental to the engine, serves 
 the very important purpose of diminishing the radiation of heat, by interposing a stratum of heated air 
 between the steam-chest and the external atmosphere. 
 
 The steam-pipe J is made of copper, and that part of it which is inclosed within the boiler is 5J 
 inches internal diameter. It enters an orifice accurately bored and fitted to receive it, in the cast-iron 
 regulator-valve chest K, which is bolted steam-tight to the exterior of the front tube-plate of the boiler. 
 The valve-chest K incloses a regulator-valve n , of a new and improved form, which, as well as the chest 
 itself, is shown on an enlarged scale in Figs. 2613, 2614. It is formed of cast-iron, and has two projecting 
 faces accurately and smoothly turned, and of such form and dimensions as, when placed in the position 
 shown in Fig. 2613, completely to cover the orifices of the two branch steam-pipes J J, whose faces are 
 bored truly cylindrical, and of the same diameter as that of the faces of the valve. The distance be- 
 tween the contiguous edges of the two branch-pipes is somewhat greater than the breadth of the valve 
 face, so that when turned round in either direction, the orifices of both pipes may be fully opened. In 
 the centre of rotation of the valve is an oblong hole, into which is fixed the correspondingly formed end 
 of a long rod o o, traversing the whole length of the boiler, and passing steam-tight through a stuffing- 
 box in the back plate of the fire-box. A long lever-handle p, is fixed to the outer extremity of this rod, 
 and the engine-driver is thereby enabled, with the greatest ease and precision, to regulate the supply 
 of steam to the cylinders. A small pipe q, screwed into the upper part of the regulator-valve chest, 
 rises through the smoke-box, and is surmounted by a cup, and provided with a stop-cock, by which oil 
 may be admitted into the interior of the valve-chest, for the lubrication of the working parts. 
 
 The two branch steam-pipes J J, as will be distinctly seen by reference to the transverse section, Fig. 
 2612, open a communication for the admission of steam from the regulator-valve chest K, into the valve 
 casing or steam-chest L L. They are each 3f inches internal diameter, and they, as well as the dis- 
 charge-pipes N N, are so disposed within the smoke-box as not to obstruct the cleaning or replacing of 
 ’ the tubes. 
 
 The cylinders and valves . — The slide-valves, with their expansion-slide frames, are placed between 
 the cylinders M M, in one steam-chest L, formed by the construction of the cylinders when bolted 
 together, as will be seen by inspection of Fig. 2606. By this arrangement access is afforded to both 
 valves by the removal of only one cover, which seems to be an improvement over the other methods 
 row in use. 
 
LOCOMOTIVE ENGINE. 
 
 2i i 
 
 The steam cylinders M M are 14 inches diameter, with a stroke of 21 inches. They are placed at a 
 slight angle in the smoke-box, for the purpose of being accommodated to the position of the cranked 
 axle. The form and dimensions of the pistons P' P', and the arrangement of the packing-rings a" a", 
 are clearly indicated in Pigs. 2615, 2016, 2617. The packing consists of two cast-iron rings a" a", 
 turned slightly eccentric, the thick sides in each being set diametrically opposite. At these points 
 they are cut, and wedges b" b" fitted accurately into the openings. These wedges are pressed out- 
 wards by two springs c" c", which are adjustable by set-sere ws. The whole is rendered compact and 
 secure, by the piston cover, d", which is bolted to the body of the piston by four bolts, guarded by the 
 pieces c" e", as shown in Fig. 2617. 
 
 The steam-ports s s, which communicate between each extremity of the cylinders and the slide-valves 
 r r, are formed in the body of the cylinders, as are also the discharge-ports N N, to the point where the 
 blast-pipes are jointed to them. The discharge or blast pipes N N, ascend from each cylinder till they 
 reach the bottom of the chimney, where they are formed into one pipe, in the orifice of which is placed 
 a cone or tapered plug t, so disposed and connected by means of a system of rods and levers u u, as to 
 be capable of being raised or depressed by the engine-driver. By this means the orifice of the blast- 
 pipe may be enlarged or contracted at pleasure, thereby causing a greater or less draught to the fire. 
 By this simple contrivance, the engine-driver is enabled to adapt the quantity of steam generated in 
 the boiler to the exact amount required for the supply of the engine, and thereby to prevent the waste 
 of fuel indicated by the steam blowing off at the safety-valve. For the further regulation of the 
 draught when the engine is at rest, it is provided with a damper v, at the lower end of the chimney, 
 worked, like the blast regulator, by a system of rods and levers, also marked v v, and terminating near 
 the foot-plate. 
 
 The framing and connections of the engine . — Having described the internal arrangements of the en- 
 gine, we now proceed to explain the parts by which motion is communicated to the wheels. These are 
 most fully and clearly delineated, iu combination, in our sectional elevation, Fig. 2605, and in the plan, 
 Fig. 2606. Between the smoke-box and external fire-box, are bolted the four strong malleable-iron 
 beams OOO, called the imide framing, and which, besides imparting great strength and rigidity to the 
 whole structure, serve the purpose of giving fixed points of resistance for the bearings of the working 
 parts. Of these, the first that claim our attention are the piston-rods P P. These are made of steel, 
 turned truly cylindrical and smooth, and of the diameter of 2 J inches ; they are fixed into the piston 
 with a cotter in the manner indicated in the detail, Figs. 2615, 2616, and at the opposite extremity they are 
 terminated each by a cross-head Q', also attached to them by a cotter, Fig. 2618. On these cross-heads 
 are bearings for the small ends of the connecting-rods Q Q ; and concentric, and of the same piece with 
 these bearings, are projecting arms into which the cast-iron guide-blocks ww, Figs. 2618, 2619, are fitted. 
 The guide-blocks are formed with flanges, and are accurately fitted and ground into steel slide-bars, 
 also marked w w, so as to work smoothly and steadily between them. These latter are set truly par- 
 allel and in the same inclined plane with the centre of the piston-rods, and are firmly bolted to the 
 framing-plates O 0. By this means, the piston-rods are constrained to 'move in a rectilinear direction, 
 and secured against any deflection, or undue strain arising from the continual change of position of the 
 opposite ends of the connecting-rods, in obedience to the revolution of the cranks to which they are 
 respectively attached. 
 
 The feed-pumps S S, for the supply of water to the boiler, are also set in the line of the piston-rods 
 and their plungers jrartake of their motion, being each fixed to a small arm x, firmly secured by a cot- 
 ter to the cross-head Q'. The pumps, the internal arrangement of which is fully shown in the longi- 
 tudinal section, Fig. 2627, are formed of cast-iron, and are firmly fastened to the inside framing O, by 
 bolts passing through the projecting flanges f" f". The plungers g" are of brass, two inches in diam- 
 eter, and at each stroke of the engine draw the water from the tender through the feed-pipe y, and 
 lower or suction valve h", forcing it, at the return stroke, through the upper or delivery valve i", and 
 along the pipe z, into the boiler. The valves are prevented from rising out of their seats by the stops 
 j"j", fixed into the covers of their respective chests, and so adjusted as to admit of their rising only to 
 the proper height for the due ingress and egress of the water. At the point where the water is dis- 
 charged into the boiler is placed a valve-box a', within which is a valve opening upwards, for the re- 
 tention of the water within the boiler. A small cock, called the pet-cock, o, is fixed to the outside of 
 ‘ be feed-pump, and by means of a long slender rod, the handle is brought within reach of the engine- 
 iriver, so that he may be enabled to ascertain at any time whether the pump is working efficiently. 
 
 The connecting-rods Q Q are jointed, as we have before explained, to the cross-heads of the piston- 
 rods. The coupling is effected in the usual way, by means of straps, gibs, and cotters, properly secured 
 against relaxing or falling out. The opposite ends are attached in the same manner to the cranks R R, 
 upon the axle of the driving-wheels. This cranked axle is made of the best forged iron, the cranks being 
 cut out of the solid mass, and the one formed exactly at right angles to the other. In the earlier stages 
 of the locomotive engine, it was usual to provide bearings for the cranked axle upon each of the frames 
 O 0, but this practice is now discontinued, and thereby the machinery is much simplified, and the fric- 
 tion considerably reduced. 
 
 The eccentrics and valve geer. — This engine is provided with four eccentrics, two for the forward, 
 and the other two for the backward geer. The form ar.d dimensions of these are shown upon an 
 enlarged scale in Fig. 2621, which gives a view of one of the backward eccentrics, but which, with 
 a slight difference, presents an accurate type of the whole set. Each eccentric is formed in halves, 
 for the purpose of embracing the axle, and these are joined immovably together by the two 
 round pins k" k", screwed into one half, and secured, after passing through the other, by cotters 
 It is fixed firmly to the axle by the two pointed set-screws, l" l". The forward eccentrics for both 
 cylinders are fixed upon the axle a little in advance of a line at right angles to their respective 
 cranks, for the purpose of giving the required lead, and the position of the backward eccentrics 
 is adjusted upon the same principle, though of course in a diametrically opposite direction. The 
 
278 
 
 LOCOMOTIVE ENGINE. 
 
 eccentric-rods m"m", are bolted firmly to the brass strap surrounding the eccentrics; and their oppo 
 site extremities, the form of which is shown in Fig. 2625, are connected together by a double link e' 
 Figs. 2623 and 2624, so formed as to admit of either forward or backward eccentric being thrown 
 into geer with the valve-spindle, as may be required. The link which Messrs. Hawthorn employ 
 for coupling the ends of their eccentric-rods is of a new and improved construction, being so formed 
 as to diminish as much as possible the friction and wear upon the slide-rod pin and the eccentric- 
 rod ends. The reversing geer, or mechanism by which the engine-driver is enabled to propel the en- 
 gine in either direction, consists of a system of rods and levers f'f'f, commencing with a stud 
 upon the lower extremity of the coupling-link e‘, and terminating in a long handle, placed in a 
 convenient position near the foot-plate. The motion of the eccentrics is communicated directly tc 
 the slide-valves by means of valve-spindles, working through oblong guides at the one extremity, to 
 insure steadiness, and attached at their opposite ends to the slide-valves by nuts and jam-nuts, for 
 the purpose of adjustment. We may here take occasion to remark, in anticipation of the subject upon 
 which we are now about to enter, that by Messrs. Hawthorn’s arrangement the ordinary slide-valves, 
 when once properly adjusted, never require to be varied, to whatever extent the expansion geer may 
 be employed. 
 
 Auxiliary expansion slide-frame and geering . — On each of the backward eccentrics is fixed a stud 
 h', Fig. 2621, to which is jointed a rod, the other extremity of which is connected with the upper arm 
 of a double lever, working upon a bearing fixed to one of the framing-beams 0 O. The lower arm of 
 this lever is grooved throughout its length to receive a sliding-pin, attached by a link to a system of 
 rods and levers, terminating in a long handle, working on the same centre with the reversing handle. 
 The sliding-pin is also connected by the rod to the hollow spindle which works through the stuffing-box 
 of the valve-chest L, and incloses the spindle g of the ordinary slide-valve. It may here be remarked, 
 as objections may be urged on the ground of expense, that the hollow spindle is not essentially requisite 
 in this arrangement of valves ; the spindle may be made solid, similar to the rod of the ordinary slide, 
 and worked through a separate stuffing-box, either above or on one side of it ; the mode represented is, 
 however, the neatest and most compact arrangement. 
 
 The expansion slide-frame is worked by the hollow spindle, being attached to it by means of a 
 slender malleable iron frame, embracing it on all sides, and screwed to the end of the hollow spindle. 
 It is fitted to and works upon the same face as the ordinary slide-valve, but is cf such a form as, when 
 the frame is in motion, to overlap alternately the ends of the latter, (the back of the slide-valve being 
 accurately planed and fitted for that purpose,) according to the amount of expansion required. This 
 can be varied at pleasure by the mechanism above described ; for when the sliding-pin which works in 
 the grooved arm is brought into the centre of motion of that lever, it is obvious that no motion of the 
 slide frame will ensue, and in this position, when it is not required to work expansively, the geering may 
 be secured so as to obviate all unnecessary wear and tear. If, however, the handle be advanced 
 into the position represented in the general elevation, Fig. 2601, the sliding-pin and rod l', which is 
 attached to it, will then be forced downwards, as shown in Fig. 2605, and the slide-frame will partake 
 of the motion communicated to the lever i' by the backward eccentric, and the amount of this travel 
 will obviously be in proportion to the distance at which the sliding-pin is set from the centre of motion. 
 A graduated sector is placed at the foot-plate in view of the engine-driver, as shown in the general 
 elevation, for the purpose of indicating minutely the amount of expansion, or at what part of the stroke 
 the steam is cut off. 
 
 W" e may remark that Messrs. Hawthorn’s expansion geer appears to possess advantages over many 
 of the other methods hitherto employed. The first and perhaps the most important of these we have 
 before adverted to, namely, the complete independence of the motion of the ordinary slide-valve from 
 that of the expansion-frame, rendering any alteration of the latter, after it has been once properly 
 adjusted, unnecessary, whatever amount of expansion may be employed. The admission and discharge 
 of the steam are thus, in all cases, regular, and take place under the most advantageous circumstances 
 attainable by the ordinary valve. Again, the movement communicated by the backward eccentric to 
 the expansion-slide is so regulated, in relation to that of the ordinary valve, as to produce a very pecu- 
 liar and advantageous effect in catting off the steam quickly. Thus, the expansive principle may be 
 employed to any extent, between that due to the cutting off of the steam at g of the stroke of the piston, 
 to that which would be produced by the action of the ordinary slide alone, without throttling, or what 
 is technically called wire-drawing the steam, a defect so much complained of in most of the other modes 
 of expansion hitherto in use. These theoretical advantages have been fully corroborated by the results 
 of experience. Messrs. Hawthorn have successfully applied their expansion geering to the locomotives 
 which they have supplied to ten different railways in England, and the saving of fuel effected by the 
 use of it, in many cases, amounts to 30 per cent. 
 
 The wheels and outside framing . — The driving-wheels TT arc firmly fixed to the cranked axle, the 
 ends of which, produced beyond the bearings, carry the cranks and coupling-rods o o'. The other 
 extremities of these rods are connected by cranks of exactly the same dimensions with the axle of the 
 fore-wheels U U. By thus connecting the driving and fore wheels, the amount of traction, or the sur- 
 face upon the rails available for the propulsion of the engine, is greatly increased, which renders this 
 species of engine peculiarly suitable for drawing merchandise or other heavy trains, at moderate speeds. 
 The hind or trailing wheels V Y, are situated under the fire-box, and the advantages of this disposition 
 have been already pointed out. The dimensions of all these wheels have also been already given, and 
 the mode of their construction will be clearly understood by reference to Fig. 2631, which shows both 
 external and sectional views of one of the driving-wheels, but which, as far as regards construction, may 
 be taken as a type of the whole. The navs is of cast-iron, moulded and poured round the arms, which 
 have been previously prepared with a dove-tail at their inner ends, for the purpose of giving additional 
 security. The arms and rim are of the best forged iron, and the latter is accurately turned in the laths* 
 
LOCOMOTIVE ENGINE. 
 
 27h 
 
 after being welded together. The tyre, which is also of the best forged scrap-iron, is bored internals 
 to a slightly smaller diameter than the rim, and shrunk on. It is then secured to the rim by a few 
 rivets, and the whole turned accurately to the proper form and diameter. 
 
 As the whole weight of the engine rests upon the wheels, it may be expected to suffer from jolting 
 in passing over the irregularities of the rails. To obviate this as far as possible, the springs p p p and 
 q q q are interposed, the former upon bearings in the outermost of the internal framings 0 O, and tin- 
 latter under the axle-boxes r r r, of the main external bearings. The springs marked q q', and the 
 mode in which they are attached to the axle-boxes and to the framing, are clearly represented in Figs 
 2634 and 2635. They are composed of thin layers of steel, gradually diminishing in length from the 
 centre to the extremities, and bound together by the connecting-hoop o", secured in its place by a small 
 round pin passing through it and the steel plates. The connecting-hoop is formed with a tail projecting 
 upwards into the lower portion of the axle-box, where it is fixed by a round pin p" passing through it. 
 The axle-box r, which is of cast-iron, fitted with bearings composed of a metallic alloy favorable for 
 Jie reduction of friction, slides up and down as the springs bend with the weight of the engine, 
 oetween the cast-iron axle-guides q" q", which are accurately planed and fitted to receive it, and 
 bolted firmly to the plates of the external framing. The axle-boxes are formed with a sort o; 
 reservoir for oil or tallow, which is constantly supplied to the rubbing surfaces by two small tubes 
 and siphon-wicks. It may here be remarked, that the other rubbing parts of the engine are lubri 
 cated in the same manner. The mechanism by which the springs are attached to the external framing 
 is shown in Figs. 2634, 2635. These parts are called the spring-links, and consist of a species of 
 small cross-head r", fitted with round pins for passing through the plates of the external framing, and 
 with screwed studs attached by similar round pins to the ends of the springs q' q. The nut s" works 
 into these screws, and by means of it the weight which it may be thought expedient to throw upon 
 each spring may be accurately adjusted. 
 
 The external framing consists of two strong parallel beams W W, extending somewhat beyond the 
 engine at both ends, and connected in front by the wooden cross-beam or buffer-bar Z, and behind by a 
 similar beam, on which rests the foot-plate Y. These beams are firmly bound together at the corners 
 by angular plates of iron bolted through each, and the weight of the boiler is supported upon them 
 by the strong malleable iron brackets or stays N N X, riveted to the boiler, and bolted through 
 the beams W W. These latter are formed each of two parallel plates of iron, cut out into the 
 form shown in the general elevation, with horns projecting downwards for the bearings of the 
 wheels. Between each pair of plates a beam of well-seasoned oak is interposed, and the whole firmly 
 bolted together. 
 
 To deaden the shocks to which the engine is exposed, it is provided with buffers, s' s', fixed to and 
 projecting in front of the buffer-bar Z. These buffers are a species of elastic cushions, formed of horse- 
 hair, surrounded by strong leather, and further strengthened by slender malleable iron hoops. To 
 secure the engine against the effects of the wheels coming in contact with stones or other obstacles 
 which may happen to be lying ou the rails, it is furnished with strong malleable iron safe-guards t' t', 
 descending from the external framing to within a short distance of each rail, and so formed at the points 
 as to turn aside any object with which they may come into collision. 
 
 Any water which may happen to accumulate in the cylinders, whether from the priming of the boiler 
 or the condensation of the steam, and which, unless removed from time to time, would be very detri- 
 mental to the working of the engine, is let off by means of the pipe and stop-cock xi, communicating 
 with the discharge passage of each cylinder. 
 
 Upon the front of the smoke-box, and towards the top, is fixed a small bracket for supporting the 
 signal-lamp v\ by which notice is given at night of the approach of the engine and train. 
 
 As a precaution against accident to the engine-driver and his assistant, hand-rails w' to' are erected 
 on each side of the foot-plate Y, and these are continued along the whole length of the boiler, so that 
 they may be enabled with comparative safety to walk round the engine, even when it is in rapid motion. 
 The rods forming this latter part of the hand-rail are made hollow, and thus afford a neat and compact 
 guide and protection for the slender rods by which the blast regulator on one side, and the damper on 
 the other, are worked. 
 
 When the engine is at rest, the steam which would otherwise escape at the safety-valve and be 
 thrown to waste, is made available for the heating of the water in the tender. This is accomplished by 
 means of the bent pipe x', by which a communication is made between the steam within the fire-box 
 and the feed-pipe y, and thereby a considerable saving of fuel is found to be effected. 
 
 The connection of the engine and tender is made by means of the strong double link or drag-bar y'. 
 one end of which is secured by a strong pin to a bracket fixed under the foot-plate of the engine, while 
 the other is in a similar manner jointed to the drag-springs of the tender. 
 
 _ To assist the engine-driver in rising into his place on the foot-plate, the foot-steps z' z' depend on each 
 side of it to within an easy distance from the ground. 
 
 Having thus minutely described the parts of which this engine is composed, and explained their sev- 
 eral uses as we went along, we consider it unnecessary to occupy more space with an account of its 
 mode of action. This is in every respect identical with that of the ordinary high-pressure engine, and 
 to those who have followed us in our previous descriptions will be perfectly intelligible. 
 
 Description of the tender . — The tender is an invariable concomitant of the locomotive engine, and as 
 in it, as well as in the engine, there is considerable room for the display of tasteful design and judicious 
 arrangement, we have thought that, we should render our engravings more interesting and more 
 acceptable by giving representations of both. The water-tank A A forms the principal part of 
 the tender, and consists of a rectangular sheet-iron cistern, capable of contaiuog 1200 gallons oi 
 water for the supply of the boiler. It is made with a long recess B for Ihe reception of the 
 fuel. The floor a of this recess is made with a slope downwards from the front of the tender, bj 
 
280 
 
 LOCOMOTIVE ENGINE. 
 
 ■which arrangement the fuel is prevented from being thrown out by any jolting or shaking to which it 
 may be subjected. 
 
 Towards the back of the tank it is surmounted by a pipe or opening C, by which water is introduced 
 from the water-crane or other contrivance for that purpose. A wooden cover is fitted over this opening 
 when not in use. At the same point are fixed the wooden tool-boxes D D for containing spanners and 
 other implements which may be required for the engine. At the front of the tank, and on each side, are 
 situated the cocks b b for regulating the supply of water to the suction-pipes c c communicating between 
 the feed-pumps and the tender. These are connected to the feed-pipes y y by means of leather hose 
 screwed on to each by the union-joints d d, thus admitting of a considerable amount of vibration or 
 change of position of the pipes, without breaking the connection. The tank is secured to a strong 
 wooden frame E E, forming the body of the tender, and strengthened by numerous cross-beams. Be- 
 yond this wooden framing, and on each side of it, the external iron framing-plates F E are fixed by bolts 
 passing through short cross-beams of timber eee abutting against both. The external framing-plates 
 are made of a form symmetrical with those of the engine, as seen in the general elevations, Figs. 2601 
 and 2603, and their purpose is to afford bearings for the reception of the axle-boxes///, which slide up 
 and down in them in obedience to the action of the springs g g g. 
 
 The tender is supported upon six wheels G G G, of the same diameter as the trailing or hind wheels 
 of the engine, and constructed in the manner already described in treating of the latter. The brake 
 apparatus, which is shown on an enlarged scale in Fig. 2636, consists of a train of mechanism by which 
 a great amount of friction can be simultaneously produced upon the peripheries of the tender-wheels, 
 for the purpose of reducing the momentum of the engine and train, when it is required to arrest the mo- 
 tion of the train. The hand-wheel h is fixed to the upper extremity of the vertical spindle H, working 
 in a strong bearing attached to the tank. The lower portion of the spindle is formed into a screw, and 
 works through the wrought-iron nut I, on which is forged a double link, jointed at its lower end to the 
 brake-lever i. The latter has its centre of motion in the short shaft J, which works in strong bearings 
 attached to the wooden frame, and carries the double-toothed sector/ Two longitudinal iron rods kk 
 extend the whole length of the tender, and a small portion of each towards the front extremity is formed 
 into a rack, so adjusted as to work into the teeth of the sector/ The rods k k are supported and guided 
 in their motion by small rollers working in the wrought-iron guides 1 1 1, and upon them are bolted the 
 wooden brake-blocks m in in, by the contact of which with the exterior surface of the wheels the friction 
 is produced. By this arrangement it is obvious that by screwing the vertical spindle H into the nut I, 
 the latter will be drawn upwards, and carrying with it the lever i, the toothed sector j will be made to 
 revolve upon its axis J, and consequently the rods k k will be drawn each in the opposite direction to 
 the other. Each wheel will therefore be forcibly compressed between the brake-blocks mm, and the 
 engine and train be proportionally retarded. 
 
 At the point where the engine is connected to the tender, the latter is provided with a system of 
 springs, to deaden the effects of shocks from either direction. This consists of two springs set back to 
 back, and connected together by a socket n, which receives the end of the drag-bar. The fore spring p 
 comes into action when any force is applied tending to separate the engine from the tender, as in start- 
 ing a train, and the hinder spring o when the force is applied in the opposite direction. Both springs 
 are supported upon pieces of thin iron bolted between the beams of the wooden frame, and the extrem- 
 ities of the spring o bear upon the two guide-pins q q. 
 
 For further security, in case of the ordinary connections failing, the safety-chains r r are attached be- 
 tween the engine and tender. 
 
 For the accommodation of the engine-man and fireman, or stoker, the tender is furnished with foot- 
 steps s s, placed at an easy distance above the steps of the engine. By these arrangements, and with 
 the assistance of the handles 1 1, the foot-plate is rendered easily accessible. 
 
 At the front of the tender a piece of boiler-plate u is fixed by hinges, for the purpose of forming a 
 floor where the engine and tender are connected. At the other extremity of the tender the buffers v v, 
 similar in construction and in situation to those formerly described, are fixed to the cross-beam of the 
 wooden framing, for the purpose of deadening the shocks produced by the occasional irregularities of 
 motion between the engine and the train. The drag-chain w, which is firmly secured to the same beam, 
 forms the connecting link between the tender and the train. 
 
 Literal References to the Engine. 
 
 A, the external fire-box. 
 
 B, the internal fire-box. 
 
 0 C, stays for strengthening the roof of the internal 
 fire-box. 
 
 a a a, stays between the external and internal fire- 
 boxes. 
 
 b, the fire-door. 
 c c, the fire-bars. 
 
 i, the movable portion of the fire-bars. 
 
 D, the ash-box. 
 
 E, the cylindrical part of the boiler. 
 eee, the tubes. 
 
 ff longitudinal stays from the back of the fire-box 
 ’ to the front of the boiler 
 
 F, the smoke-box. 
 
 n g, the smoke-box doors. 
 
 G, the chimney. 
 
 H, a brass funnel for inclosing the safety-valves. 
 
 h, the spring safety-valve. 
 
 i, the lever safety-valve and spring-balance. 
 
 / the water-gage, and gage-cocks. 
 
 k, the steam-whistle. 
 
 I, the blow-off cock. 
 
 l, the steam-receiver. 
 
 in, the inverted cone for preventing priming. 
 
 J J, the steam-pipes. 
 
 K, the regulator valve-chest. 
 
 n, the regulator valve. 
 
 o, a rod connecting the regulator valve with 
 
 p, the handle for working it. 
 
 q, the oil-cup and pipe for lubricating the regulator 
 valve. 
 
LOCOMOTIVE ENGINE. 
 
 281 
 
 L, the steam-chest of the cylinders, 
 r r, the slide-valves. 
 
 M M, the steam-cylinders, 
 s s, the steam-ports. 
 
 N N, the discharge-ports and blast-pipes. 
 t, the blast-regulator. 
 
 u u, handle, rods, and levers for working the blast- 
 regulator. 
 
 v v, the damper, with the handle, rods, and levers 
 for working it. 
 
 O O, the inside framing of the engine. 
 
 P', the steam-piston, 
 a" a", the packing-rings of the piston. 
 b” b", wedges for tightening the packing. 
 c" c", springs bearing on the back of the wedges 
 b"b". 
 
 d", the piston-cover. 
 
 ' e", guards for the bolts of the piston-cover. 
 
 P P, the piston-rods. 
 
 Q' Q', cross-heads for the piston-rods. 
 w w, the cross-head slides. 
 
 x x , projecting-arms for working the feed-pumps. 
 
 Q Q, the connecting-rods. 
 
 R, the cranked axle. 
 
 S S, the feed-pumps. 
 
 f" f", flanges for bolting the feed-pumps to the in- 
 side framing. 
 
 g'' g", the plungers of the feed-pumps. 
 h", lower or suction valve of the feed-pump. 
 i", upper or delivery valve. 
 j"j", stops for regulating the lift of the valves. 
 yy, the feed-pipes from the tender to the feed- 
 pumps. 
 
 z z, branch-pipes from the feed-pumps to the boiler. 
 a' a', valve-boxes at the boiler. 
 b‘ b', the pet-cocks and their handles, 
 o' o', the forward eccentrics. 
 d' d', the backward eccentrics. 
 k" k", bolts for connecting the halves of each ec- 
 centric. 
 
 I" l", steel pinching-screws for fixing the eccentrics 
 to the axle. 
 
 m" in", the eccentric-rods. 
 
 e' e' , coupling links for the ends of the eccentric- 
 rods. 
 
 levers, shafts, and rods for working the re- 
 versing-geer. 
 
 Literal Rcferen 
 
 A, The water-tank. 
 
 B, the recess for containing the coke. 
 a a, the floor of the coke-box. 
 
 C, the opening into the tank. 
 
 D D, the tool boxes. 
 
 b b, the cocks for regulating the supply of water to 
 the feed-pumps. 
 
 c c, water or suction pipes to the engine. 
 dd, union-joints for connecting the feed-pipes. 
 
 E E, wooden frame of the tender. 
 e e, stays between the wooden and iron frames. 
 
 F F, the iron frame for receiving the axle- 
 boxes. 
 
 fff the axle-boxes. 
 g g g, the springs. 
 
 GG6, the wheels. 
 
 H, the vertical spindle and screw for working the 
 brake. 
 
 h, the hand-wheel for the brake-screw. 
 
 g' g', the main steam-valve spindles. 
 h’ h', studs on the backward eccentrics for working 
 the expansion slide-frames. 
 n" n ", connecting-rods between the studs h' h' 
 and 
 
 V i', the grooved arms for the variable expansion. 
 j’j', links between the grooved arms and the lev- 
 ers k’ k'. 
 
 k' k' k' , levers, shafts, and rods for regulating the 
 expansion-geer. 
 
 V l', connecting-rods between the grooved arm a 
 i' i', and 
 
 m' m', the hollow spindles attached to 
 n' n' , the expansion slide-frames. 
 
 T T, the driving-wheels. 
 
 o' o', the outside cranks and coupling-rods. 
 
 U U, the fore-wheels coupled to the driving- 
 wheels. 
 
 V V, the hind- wheels under the fire-box. 
 
 p' p', springs for the inside bearings of the cranked 
 axle. . 
 
 q' q', springs for the outside bearings of all the 
 axles. 
 
 o" o ", connecting-hoop for the outside springs o l 
 the cranked axle. 
 r' r', the axle-boxes. 
 
 p" p", pins for attaching the springs to the axle- 
 boxes. 
 
 q" q”, cast-iron guides for the axle-boxes. 
 r" r" , the spring-links. 
 
 s''s", the nuts for adjusting the weight upon the 
 springs. 
 
 W W, the external frame of the engine. 
 
 X X, stays from the external frame to the 
 boiler. 
 
 Y, the foot-plate. 
 
 Z, the buffer-beam. 
 s' s', the buffers. 
 t't', the safeguards. 
 
 u' u', a cock and pipe for letting off water from the 
 cylinders. 
 v', the signal-lamp. 
 w'w', the hand-railing. 
 
 x', a pipe from the boiler for heating the water in 
 the tender. 
 y’, the drag-bar. 
 
 2 ' 2 ', the foot-steps. 
 
 •es to the Tender. 
 
 I, the nut and link for connecting the screw witn 
 
 i, the brake-lever. 
 
 J, the short shaft carrying the brake-lever, and 
 
 j, the double-toothed sector, working into 
 
 k k, the longitudinal rods carrying the brake- 
 blocks. 
 
 1 1, supports fitted with rollers for guiding the 
 rods kk. 
 
 mm, the wooden brake-blocks. 
 n, socket for connecting the drag-springs to the 
 drag-bars. 
 
 op, the springs for buffing and drawing. 
 q q, bearings for the spring o. 
 r r, the safety-chains, 
 s s, the foot-steps. 
 
 1 1, handles to assist in rising to the foot-plate. 
 u, a hinged plate between the engine and tender. 
 v v, buffers for the tender. 
 w, drag-chain of the tender. 
 
 Fig. 263V is an elevation of a small American locomotive built by H. R. Dunham & Co., New York 
 The distinctive part of the engine and of American locomotives in general, is the forward truck consist- 
 
282 
 
 LOCOMOTIVE ENGINE 
 
 ing of two sets of wheels on one frame, the frame revolving on a centre-pin, which enables the machine 
 to move more easily around corners ; this form of engine is called the bogey in England. 
 
 The locomotive here shown is one of the earlier kind, with inside connection, and hut one pair of 
 drivers. At present in this country, engines with outside connections are thought to be safer, steadier 
 and cheaper than inside, and are very generally adopted. The number of rb-iving wheels is seldom lesl 
 than two pairs. Fig. 2638 is the side elevation of a locomotive as built b; Rogers, Ketchum & Gros 
 
 vner of Paterson, and may be taken as the type of the American locomotive. The earliest American 
 locomotives were but copies of the English with slight adaptations, for the service required and fuel used, 
 but the later engines, as will be seen, are distinctive. 
 
 The valve- o-eer now mostly used is the link-motion, for description of which see Link-Motion. 
 
 The coal locomotives as built by Ross & Winans of Baltimore, differ essentially from those of othei 
 
LOCOMOTIVE ENGINE. 
 
 283 
 
 makers. The freight engines are usually eight-wheeled engines, all connected ; the fire-hox is extremely 
 long and capacious. The fuel is let down through a hopper above the fire-hox, the tender being two- 
 storied, and the engineer is placed on the top of the engine, immediately back of the smoke-stack. For 
 the results of experiments on these engines on the Beading Bailroad see Boiler. 
 
 Coal engines, as bunt by Perkins of Alexandria, have three pairs of connected drivers and a forward 
 truck. The coal engines of other makers are in general appearance similar to the wood engine, til e dif- 
 ference being almost entirely in the form of the boiler. 
 
284 
 
 LOGARITHMS. 
 
 LOGARITHM. The logarithm of a number is the exponent of a power to which another given inva- 
 riable number must be raised in order to produce the first number. Thus, in the common system o( 
 logarithms, in which the invariable number is 10, the logarithm of 1000 is 3, because 10 raised to the 
 third power is 1000. In general, if a x =y, in which equation a is a given invariable number, then x is 
 the logarithm of y. All absolute numbers, whether positive or negative, whole or fractional, may be 
 produced by raising an invariable number to suitable powers. The invariable number is called the base 
 of the system of logarithms : it may be any number whatever greater or less than unity ; but having 
 been once chosen, it must remain the same for the formation of all numbers in the same system. What- 
 ever number may be selected for the base, the logarithm of the base is 1, and the logarithm of 1 is 0. 
 In fact, if in the equation a*=y we make a-=l , we shall have a 1 — a, whence, by the definition, log. 
 a— 1 ; and if we make x=0, we shall have a <l =l, whence log. 1=0. 
 
 These properties of logarithms are of very great importance in facilitating the arithmetical opera- 
 tions of multiplication and division. For if a multiplication is to be effected, it is only necessary to 
 take from the logarithmic tables the logarithms of the factors, and add them into one sum, which gives 
 the logarithm of the required product ; and on finding in the table the number corresponding to this 
 new logarithm, the product itself is obtained. Thus by means of a table of logarithms the operation 
 of multiplication is performed by simple addition. In like manner, if one number is to be divided by 
 another, it is only necessary to subtract the logarithm of the divisor from that of the dividend, and to 
 find in the table the number corresponding to this difference, which number is the quotient required. 
 Thus, the quotient of a division is obtained by simple subtraction. 
 
 Logarithms apply with equal advantage to the formation of powers and extraction of roots. Let y 
 be a number to be raised to the power m, ( m being any number, whole or fractional, positive or negar 
 tive.) As before, we have y=a* ; and, on raising both sides of the equation to the power m, y m =a m x: 
 whence, by the definition, log. y m =m x—m log. y ; that is, the logarithm of the power of a number is 
 equal to the product of the logarithm of the number by the exponent of the power. 
 
 If in the equation of log. y m = m log. y we make m — -, we shall have log. y “ (or log. y) = - log. 
 
 y ; that is to say, the logarithm of any root of a number is equal to the logarithm of the number divi- 
 ded by the index of the root. 
 
 From these two last results it is obvious that by means of a table of logarithms numbers may be 
 raised to any power by simple multiplication, and that the roots of numbers may be extracted by sim- 
 ple division. 
 
 When a table of logarithms has been calculated for any given base, it is easy to find by means of it 
 any other system of logarithms corresponding to a different base. Thus, supposing a system of loga- 
 rithms has been calculated of which the base is a, or, which is the same thing, that the value of x has 
 been found for every different value of y in the equation a x —y, and that it is required to construct 
 another table, of which the base is b, or to find the values of v corresponding to every different value 
 of y in the equation b v = y, we may proceed as follows : Taking the logarithms of both members of 
 this last equation from the table supposed already calculated, of which the base is a, and recollecting 
 
 log. y 
 
 that log. b v — v log. b, we have v log. b = log. y ; whence v = ^ v ' . But because b T = y, it follows that 
 v is the logarithm of y in the system of which the base is b ; therefore, denoting the logarithms in this 
 new system by L, we have L y — ^ p ~ jf . Hence it appears that, in order to find the logarithm of any 
 given number y in the new system, it is only necessary to multiply its logarithm in the system already 
 
 calculated by the constant number , -. This constant number, by means of which we pass from the 
 
 J log. b J 
 
 one table to the other, is called the modulus of the new table with reference to the old. 
 
 The logarithms of the particular system of which the modulus is 1, is called the Napierian system. 
 But, as has been shown, when the logarithms have been found in any one system, they may be trans- 
 ferred into those of any other system by means of a constant factor. In the common system the base 
 is 10, and the Napierian logarithm of any number is consequently transformed into the common loga- 
 
 rithm of the same number by multiplying by the modulus 
 
 1 
 
 lTo' 
 
 This number, which is of great im- 
 
 portance in the computation of the logarithmic tables, is found to be 0'4342944819, &.C., the Napierian 
 logarithm of 10 being 2'30258509, &c. It may also be remarked that this modulus 0'4342944819 is 
 the ordinary logarithm of the base of the Napierian system; for, calling e this base, we shall have 
 
 e = 10, whence, taking the ordinary logarithm of both sides of the equation L10 Xlog. e = log. 10 = 1; 
 therefore, log. e — — — - = 0-4342944819. On passing to numbers, we find e — 2-7182818284. 
 
 The Napierian logarithms are sometimes called the natural logarithms , on account of the modulus oi 
 the system being unity ; and, more frequently, hyperbolic logarithms, because they represent the area 
 of a rectangular hyperbola between its asymptotes, and on this account are of immense use in calcula 
 lions connected with the steam-engine. 
 
 Logarithms being of constant use in calculations, the tables which have bean published are very 
 numerous. The most complete are those of Ylacq, to ten decimals ; but they are very scarce, and can 
 with difficulty be procured. There is an edition of them by Vega, in 1797, also scarce. Gardiner’s 
 Logarithms, printed in 1742, in 4to, and another edition of them at Avignon, in France, in 1770. are to 
 seven decimals. Collet’s Logarithms, in 8vo, like Gardiner’s, contain the logarithmic sines, &c., loi 
 
LOOM, POWER. 
 
 285 
 
 every 10 seconds. Taylor’s Logarithms , in 4to, and also Baguay’s , have them to every second. Hut- 
 ton’s Logarithms, and Babbage’s Logarithms of Numbers, are well known. The latter was carefully 
 collated, and is very accurate and convenient. Hulsse’s Sammlung Mathematischer Tafeln (8vo. Leip- 
 sig, 1840) deserves to be mentioned as a very useful collection. The above (excepting Vlacq’s and 
 Yega’s) are all to seven decimal figures; hut for many purposes, logarithms to a less number of deci- 
 mals are sufficiently accurate. For navigation and surveying, tables to six fixgures are the most con- 
 venient, as they give, in general, the trigonometrical lines correct to single seconds. The best tables of 
 this kind are Farley’s Tables of Six-figure Logarithms, (12mo, 1840.) For many auxiliary computations 
 in astronomy it is sufficient to have the logarithms to five places. The reprint of Lalandc’s Five-figure 
 Table by the Useful Knowledge Society (18mo, 1839) is convenient, and may be relied on for accuracy. 
 
 LOG, for steam-vessels. Fig. 2649 is a side view, and 
 Fig. 2650 an end view of this instrument. A is a small 
 wheel, 1 foot diameter, having vanes set at such an angle 
 that, when let into the water, the action upon their in- 
 clined surfaces would cause the wheel to revolve once in 
 passing the distance of two feet through the water. 
 
 Upon the axis of the wheel is an endless screw a, into 
 which works a small toothed wheel, having 51 teeth. 
 
 The instrument should be mounted on the low end of a 
 stiff bar of wood, or other material, of such length as 
 that the top end could be fastened by a joint or hinge b, 
 to the side of a vessel, in convenient proximity to a 
 cabin window, or to the deck. To the low end of the 
 rod or bar a small line should be attached, c, the other 
 end of which to be secured on the deck of the vessel. 
 
 The use of this line would be to withdraw the instru- 
 ment from the water when not required for observation, 
 and to lash it horizontally out of the reach of the waves. 
 
 When the line was released, the instrument should be so 
 suspended as to fall perpendicularly into the water, and 
 the bar sufficiently stiff to remain perpendicular, and re- 
 sist the pressure of the water against its front edges, 
 which, however, would be but trifling. The axis of the 
 small toothed wheel should be inclosed in a tube in 
 front of the bar on which the wheel is suspended, and 
 prolonged to a short distance below the hinged joint ; 
 and upon the top end of it should be fixed an index d, 
 to revolve on a dial-plate decimally divided. The wheel 
 being constructed as before described, this index would 
 make one revolution round the dial-plate in the time 
 that the vessel passed 102 feet through the water, which 
 is about the one-sixtieth part of a knot, or nautical mile. If, therefore, an observer stood with a minute- 
 glass, (or seconds watch,) and turned the glass the moment the index was at zero upon the dial-plate, 
 and noted the number of revolutions and parts made by the index during the time the sand was running 
 out, he would have the rate at which the vessel passed through the water, in knots and decimals, per 
 hour. 
 
 LOGWOOD. A hard, compact wood, so heavy as to sink in water, of a fine grain, capable of being 
 polished, and so durable as to be scarcely susceptible of decay. Its predominant color is red, tinged 
 with orange, yellow, and black. It yields its color both to spirituous and watery menstrua. Alcohol 
 extracts it more readily and copiously than water. The color of its dye is a fine red, inclined a little 
 to violet or purple, which left to itself, becomes yellowish, purple, and at length black. Acids turn it 
 yellow, alkalies deepen the color, and give it a purple or violet hue. A blue color is obtained from 
 logwood, by mixing verdigris with it in the dye-bath. The great consumption of logwood is for blacks, 
 to which it gives a lustre and velvety cast ; it is also extensively used as a red, purple, or black dye to 
 beech, and various white woods. See Woods, Varieties of. 
 
 LOOM, POWER. Fig. 2651 is a front elevation of a power-loom for weaving printing goods, as built 
 in the Lowell Machine Shop, Lowell, Mass. 
 
 Fig. 2652 is the driving-end, showing pulleys, geers, shipper, Ac. 
 
 Fig. 2653 is a view of the other end, showing the take-up motion. 
 
 A denotes the cast-iron ends, which, with the iron girts that are bolted between, constitute the frame- 
 work to which all other parts are attached. 
 
 B is a cast-iron arch, which supports the roll over which the harnesses hang. 
 
 C C are the driving-pulleys, one loose, the other fast. 
 
 D, large geer or cam shaft, driven by a geer on the crank-shaft. 
 
 E, cams for working the harnesses ; F, cam for throwing shuttle. 
 
 G, lever for taking up the cloth by operating on the ratchet-wheel H. This lever is worked by a 
 jrank-motion attached to the end of cam-shaft. 
 
 H, ratchet-wheel, operated by lever G. 
 
 I, emery-roll ; J, binder-roll; K, cloth-roll. The cloth, after passing between the rolls I and J, windi 
 up on this roll. This roll is driven from I by a belt. 
 
 L, Fig. 2652, is a view of the filling stop-motion. 
 
 M, head on yarn-beam, with a groove for a strap. 
 
 N, strap and spring for friction on yarn-beam. 
 
286 
 
 LOOM, POWER. 
 
 # 
 
 O, lever, operated by cam, on cam-shaft. 
 
 P, lever attached to O, which comes in contact with catch L, (when the filling breaks,) and throws tli* 
 shipper-handle Q out of the notch in which it is held, and stops the loom. 
 
 Q, shipper-handle for stopping and starting the loom. 
 
 R, piece attached to the protecting-rod, that strikes a lever under the breast-beam, (whenever tha 
 shuttle fails of performing its duty,) and stops the loom. 
 
 S, picker-staff for throwing the shuttle, which receives its motion from a cam on cam-shaft, commu 
 aicated by a treadle and strap T. 
 
 T, strap for picker-motion. 
 
 IT, harness-treadles, operated by the cams E E. 
 
 V, crank-shaft, which gives motion to the lathe or sley. X, sley or lathe, which contains the reed. 
 
 Y, harnesses for separating the warps while the filling passes through, which are operated by th« 
 narness-cam E alternately. 
 
LOOM, COUNTERPANE. 
 
 287 
 
 Z Z are the swords that support the lathe, and are attached to the rocking-shaft at the bottom. 
 
 «fc, rocking-shaft on which the lathe swings. 
 
 a' is a geer attached to the yarn-beam, used only when dressing the yarn. V , reed, c', friction roll 
 for picker-lever strap, d', picker-levers or treadles, e', race-rods, on which the pickers slide. /', pickers, 
 made of green hide, dried and pressed, g', temples for holding the cloth in its place and keeping it 
 stretched in width. h‘ is the cloth, as it passes over the breast-beam down between the two rolls on 
 to the cloth-roll. 
 
 LOOM, BIGELOW’S COUNTERPANE. This improvement consists principally in the manner in 
 which the shuttles are thrown; the manner of raising and depressing the shuttle-boxes; and the man- 
 ner in which the picker is relieved from the shuttle. 
 
 We copy from the specification of the patentee : 
 
 In throwing the shuttles, I cause the two picker-staves to operate simultaneously, so that the shuttle 
 may be thrown from whichever of the boxes is presented to their action. This I effect by the use of one 
 picker-treadle only, which is acted upon by a cam-ball, in the usual way of working such treadles. 
 From this treadle two bands are extended, and pass around the two picker-pulleys in such manner that 
 when the treadle is depressed both the picker-staves will be set in action at the same moment. By this 
 arrangement, two or more shuttles may be successively thrown from the same end of the loom by the 
 action of one treadle. 
 
 The shuttle-boxes are raised and lowered in the following manner : a shaft extends along under the 
 race-beam, from one shuttle-box to the other, and carries pinions, which take into racks attached to the 
 shuttle-boxes ; it will be manifest, therefore, that by causing this shaft to revolve, the shuttle-boxes may 
 be raised. The revolving of this shaft is effected by the action of a spiral or other spring, one end of 
 which is attached to the frame of the loom at its back, and said spring extends forwards towards the 
 lathe ; from this forward end a band attached to it passes round guide-pulleys, the situation of which 
 will be shown in the accompanying drawing, and also round a pulley upon the above-named shaft, to 
 which latter said band is attached. The action of the spring, by its drawing upon the band, will cause 
 the pinion-shaft to revolve, and will consequently raise the shuttle-boxes. Should this spring be thrown 
 out of action, and the band by which the shuttle-boxes are raised be relaxed, they will then descend by 
 their own gravity. To take off the tension of the spring, there is a cam upon the main shaft of the loom, 
 which cam, as the shaft revolves, depresses a treadle, to the end of which a band is attached, which 
 operates in such a way as to relieve the shuttle-boxes from the action of the spring, and they then de- 
 scend. In relieving the picker from the point of the shuttle, I make use of the protection-rod consti- 
 tuting a part of the apparatus employed in the ordinary power-loom, for stopping the loom when the 
 shuttle does not arrive home in the shuttle-box. From the protection-rod, which extends along below 
 the shuttle-boxes, I allow a small arm or finger to descend, which finger, as the lathe comes up towards 
 the breast-beam, strikes against a stop or pin, attached, for that purpose, to the frame of the loom, caus- 
 ing the protection-rod to rock or revolve to a short distance. This gives motion to two arms which 
 extend out from the extreme ends of the protection-rod, opposite to the outer ends of each of the shuttle- 
 boxes ; from these arms motion is communicated to a lever which works on a fulcrum over the outer 
 ends of each of the shuttle-boxes, said arms being connected to the levers by rods or wires. By depress- 
 ing the outer ends of these levers their inner ends are raised, and to these ends are appended rods 
 which carry pieces of wood or metal, which, when down, rest on and embrace the picker-rod, and in 
 that position they serve to hold the picker at a short distance from the end of the shuttle-box, and to 
 stop the shuttle ; the picker is then removed from the point of the shuttle by the raising of the lever, 
 the picker being made to pass home to the end of the box, thus leaving’ the shuttle and shuttle-box free 
 to be raised or lowered without obstruction, the picker being also ready again to act on a shuttle. 
 
 Having thus given a general description of my improvements, I now proceed to exemplify the same 
 by references to the accompanying drawings. 
 
 Fig. 2654 is a front view, in perspective, of my improved counterpane power-loom, and Fig. 2655 a back 
 view of one end of one of the shuttle-boxes, this being drawn for the purpose of showing the particular 
 construction and arrangement of this part of the machinery, which could not be exhibited in the front 
 view. In Fig. 2654 the breast-beam is not represented, it being removed for the purpose of showing 
 the lathe, and the parts connected therewith, the more distinctly. The jacquard apparatus, which is 
 employed to regulate the figure, and is perfectly well known, being in general use, I also use as hereto- 
 fore constructed. It is not represented in the drawing, it not being deemed necessary to describe it ; 
 but I have fully shown those parts which constitute my improvements. 
 
 A A are the picker-staves, and B the picker-treadle ; D is the cam-ball for working this treadle, oper- 
 ating in the usual manner. E E are two straps which are attached to the picker-treadle ; these straps 
 pass over the pulleys F F, and are attached by their outer ends to the pulleys G G, which carry the 
 staves A A, and these are consequently acted upon simultaneously. The rods or staves A' A' serve to 
 cause the pickers to pass home when the pieces of wood, &c., above referred to, are raised ; these rods 
 are drawn towards the outer ends of the shuttle-boxes by the action of the spiral springs 0 C, the use 
 of which will more fully appear when describing the parts shown in Fig. 2655. 
 
 The following is the arrangement devised by me for raising and depressing the shuttle-boxes : a shaft 
 H H is made to extend along under the race-beam, and this shaft carries the pinions 1 1, which take into 
 vertical racks J J attached to the shuttle-boxes. I sometimes use a single rack affixed at the middle of 
 each box ; but I prefer the placing of a rack and pinion at each end of each box, as shown in the draw 
 ing. There is a pulley L on the shaft H, and this shaft is made to revolve by means of a band K, one 
 end of which is attached to and laps around the said pulley. The baud K passes thence around pulleys 
 act.', the pulley a being attached to the frame, and the pulley a' either to the frame or to the floor. The 
 spiral spring M affixed to the back of the loom draws on the band K attached to its fore end, so as to 
 cause the pulley L and the shaft H to revolve and raise the shuttle-boxes. When the spiral spring M 
 is relieved from its action on the band K, the shuttle-boxes will descend by their own gravity When 
 
288 
 
 LOOM, COUNTERPANE. 
 
 this is to take place, the tension of the spring is taken off by the action of the cam N, placed on the 
 main shaft of the loom, which cam is so formed as to depress the treadle O, which, drawing on the part 
 P of the band Iv, takes off the action of the spiral spring therefrom, and the shuttle-boxes descend. 
 
 The protection-rod Q Q and its appendages, used for stopping the loom when the shuttle does net 
 arrive home, are employed by me iu the ordinary way ; but I also make use of this protection -rod for 
 the purpose of relieving the shuttle from the picker, in the following manner : R is an arm or finger 
 which is affixed to and descends from the protection-rod, and this, as the lathe approaches the breast- 
 beam, strikes against the stop S attached to the frame of the loom, and causes a partial revolution of 
 the protection-rod. T T are arms on its extreme ends, which arms are connected to two vibrating levers 
 U U, by a rod z z, which work on fulcra on the ends of the lathe, above the shuttle-box. 
 
 >:*3 
 
 O 
 
 ci 
 
 Fig. 2655 is a back view of the outer end of one of the shuttle-boxes, showing the manner in which 
 die lever U and its appendages operate. The piece of wood or metal Y which is raised and lowered 
 by the action of the lever U, and which is represented as resting on the picker W, will, when the inner 
 end of the lever U is down, rest upon the picker-rod X, where it serves to arrest the picker and stop 
 the shuttle. When the lever U is raised, the picker is thereby allowed to pass home, and is conse- 
 quently removed from the point of the shuttle, and this and the shuttle-box are left free to be raised or 
 lowered. The ro*d A' bears against the pin b projecting from the picker, and serves to remove it from 
 
LOOM, DOUBLE-STROKE. 
 
 289 
 
 the shuttle -when the piece Y is raised. The rods c c support the pin l>, and serve as guides to the rod 
 A'; the cord d connects the upper end of the rod A' to the upper end of the stave A, in order that the 
 stave may by its motion move the rod also. 
 
 I -will here remark, that a weight may be substituted for the spiral or other spring M ; that the 
 shuttle-boxes may be raised by springs placed immediately under them, and that the tension of such 
 springs may be taken off by means analogous to those described ; but it will be manifest to every com- 
 petent machinist that any such variation of the respective parts will not substantially change the char- 
 acter of my invention. The manner of constructing and arranging the apparatus as set forth by me, is 
 that which I have deemed the best in practice. 
 
290 
 
 LOOM, DOUBLE-STROKE. 
 
 Fig. 2659, illustration of the movement which operates the picker-staff. 
 
 Figs. 2660 ami 2661, shuttle. Fig. 2658, elevation of the loom on the side of the warp. 
 
 Figs. 2662 and 2663, plan and section of the brake. 
 
 Fig. 2664, plan of one of the shuttle-boxes. 
 
 A, warp-beam. B B 1 B 2 B 3 B 4 , frame of the loom, b b, supports of the shaft of the drum C, fastened 
 to the uprights of the frame by set-screws. C, wooden drum, dd', blocks to preserve separate tha 
 
 threads of the warp. E E', harness for raising and lowering the threads of the warp for the passage oi 
 the shuttle. F, breast-beam. G, cloth-beam. H, spur-wheel on the shaft of the cloth-beam, f pinion 
 working into the wheel H. I, ratchet-wheel, which works with the pinion. J, bell-crank, moving on 
 the centre n, and carrying the clicks g g' and the counterpoise j. g, lay-click, serving to give motion to 
 the ratchet-wheel, g' g', stop-clicks, to arrest the movements of the ratchet-wheel, i, pin on one of the 
 swords of the lay, to give motion to the bell-crank J. K, spur-wheel on the shaft of the drum A, work 
 mg with the pinion k k pinion of 12 teeth, fixed to the shaft which carries the brake-pulley L, Fig 
 
LOOM, CARPET-WEAVING. 
 
 291 
 
 265S, and also Figs. 2662 and 2663. m, cord, fastened at one end to a spiral spring, and passing ovei 
 the pulley M, supports the counterpoises M', formed of iron rings. N N', needles, ■which give movement 
 to the harness of the treadles, one shorter than the other. 0 O', two eccentrics, cast in the same piece, 
 serving to give motion to the treadles, and consequently to raise and lower the harness. P, shaft car- 
 rying the eccentrics of the treadles, and also the cranks Z, which give motion to the picker-staff. P', 
 spur-wheel on the shaft P. Q, pinion, of half the diameter of the wheel P, and giving motion to it. 
 Q', a driving-shaft of the machine. R R', fast and loose pulleys on the shaft Q. for the working of the 
 machine. S S', eccentrics, by means of which a double beat is given to the lay V at each revolution oi 
 the main shaft. t 1', friction-rollers at the ends of the swords of the lay, to receive the action of the 
 eccentrics S S'. T, two swords of the lay. U, lay or batten, on which traverse the shuttles. V, shut- 
 tles ; X, picker-staff; x, picker strings, x, pickers of hide, serving to throw the shuttle, x 2 , guide-rods 
 to the pickers. Y, wooden levers, sunk in the substance of the cheeks of the lay, and turning on the 
 pin y. y y 1 y 3 y 4 y b , details of the stop-motion by which the loom is thrown out of geer by a failure ol 
 the proper motion of the shuttle. Z, two cranks on the shaft P, giving motion to the picker-staff by 
 means of friction-rollers z on the ends of the crank, working upon inclines z. Z 2 . two levers, connected 
 witli the axes of the picker-staffs, and united by means of straps to a spiral spring Z 3 . 
 
 LOOM, POWER CARPET, for weaving two or three ply ingrain or Kidderminster carpets, by E. B. 
 Bigelow. It gives peculiar interest to the description of a valuable and meritorious invention, to pre- 
 cede it by some account of the life an 1 character of the inventor. The mind loves to contemplate the 
 early struggles of genius, to perceive and comprehend its first inspirations, and step by step to trace 
 the development of its powers. 
 
 Erastus B. Bigelow was born at West Boylston, Massachusetts, in April, 1814. Plis father was a 
 cotton manufacturer, which circumstance, we have a right to assume, gave to the son’s mind its first 
 tendency towards that peculiar branch of mechanical pursuits in which he has now attained an envia- 
 ble and undisputed eminence. His parents, however, designed him for the medical profession ; but 
 such a misdirection of faculties was not predestined by the “ Divinity that shapes our ends.” Before 
 he had completed his medical education, his father, in common with many others engaged in man- 
 ufactures at that time, failed in business, and was unable to complete the education of his son. What 
 appeared at first a severe private calamity, has, -under a wise Providence, resulted in great public 
 good. 
 
 Finding himself without means to prosecute his medical studies, young Bigelow yielded to that ne- 
 cessity which has so often proved the benign mother of early invention, and determined to direct his 
 ingenuity to the contrivance of some piece of mechanism, from which he might obtain some pecuniary 
 benefit. Whilst his thoughts were directed to that object, he happened one day to be lying on a bed 
 covered with a knotted counterpane, a species of fabric in which the figure on the surface appears as if 
 made by tying into knots the threads of the woof ; and as, some years before, an attempt had been 
 made in West Boylston (where he was still living) to manufacture such counterpanes on hand-looms, 
 and abandoned on account of the great labor and expense involved, three or four days being required 
 to make one counterpane, it became evident to his mind that if he could succeed in producing a power- 
 loom for this purpose, it would be highly valuable as a labor-saving machine, and that he could derive 
 from it the pecuniary assistance for the want of which his medical studies had been suspended. It was 
 a bold undertaking for one wholly uninitiated in the mysteries of the mechanic art, but his very inex- 
 perience was to him a great benefit, by concealing from his sight the enormous mechanical difficulties 
 he would have to encounter, and which, if then fully known, might have deterred him from ever carry- 
 ing his purpose into execution. We may here notice this remarkable fact, that the most original and 
 important inventions the world has ever seen, were the productions of men who had received little or 
 no previous training in the particular art which they sought to improve. Jacquard, the inventor of 
 the beautiful mechanism which bears his name, for weaving figured fabrics, is the only exception 
 with which we are acquainted. It would seem that in pursuing any avocation steadily, the mind 
 becomes so habituated to a certain practical routine, as to make it distrustful of any other ; whilst, 
 on the other hand, a mere novice, from the fact of his approaching the subject untrammelled by 
 habit or prejudice, will be better fitted to detect existing errors, and suggest bold and original improve- 
 ments. 
 
 But to return. This new idea, forced by circumstances upon Mr. Bigelow’s mind, he prosecuted so 
 vigorously, that in the course of one year he hail an automatic loom for weaving knotted counterpanes 
 in successful operation, doing the work in one-fourth of the time required by the hand-loom. 
 
 The loom was arranged with every fourth dent of the reed adapted to slide vertically in the lathe, and 
 with a hook on the front edge. To the lower end of each of these hooked dents was suspended a wire, 
 attached at its lower end to one end of a lever, and the series of levers were acted upon at the other 
 end by tappets, arranged in a helical line on a barrel or cylinder, for the purpose of depressing the 
 hooked dents in succession from one side of the lathe to the other. The levers and dents were so weighted 
 as to remain in a depressed position, with the hooks below the race-beam, to permit the passage of the 
 shuttle, and when elevated they were held up by the pressure of a spring on each one. For the pro- 
 duction of the figure, the hooks, or rather that portion of them required each time, were operated every 
 fourth pick or throw of the shuttle, and after the fourth throw of the shuttle, the required portion of 
 hooked dents were elevated above the weft-thread, the upper part of the hooks being curved, to admit 
 of its passing by the weft-thread ; and then, when drawn down, each hook in succession caught the weft 
 and drew it down below the line of the bottom warps, to form the loop, so that when the weft-thread 
 was beaten up by the reed, and the warps crossed, each loop would project to the required distance 
 above the face of the cloth. To insure the proper action of the hooks on the weft-thread, there was a 
 plate imbedded in the race-board, and adapted to slide up and down, and having a notch corresponding 
 with each hooked dent. This plate was brought up under the warps just before the hooked dents were 
 denressed, and formed a bed for the hooks to draw the weft-thread down. The selection of the hooked 
 
292 
 
 LOOM, CAE PET- WEAVING. 
 
 dents required to be elevated and depressed, for each operation to determine the figure was effected by 
 a series of needles, on the principle of the jacquard, and governed by punched cards ; but these nee- 
 dles, instead of being used to operate knotted cards, were, at their outer ends, joined to wire hooks 
 connected with the levers of the hooked dents, and when the needles were acted upon by the cards, 
 the hooked wires of such of the levers as were to be operated to lift the dents were brought 
 within the range of motion of a lifting-bar, which carried them up where they were held by the 
 spring before described ; the lifting-bar was then depressed, and then, as the tappets on the barrel 
 passed around, the lifted hooked dents were eacli in succession drawn down to form the series of 
 loops. 
 
 This loom was so ingenious, and worked so well, that our young inventor soon found capital- 
 ists able and willing to furnish the means necessary for the enterprise, and a patent was secured 
 for the invention in the United States, on the 6th day of January, 1838, and in England the same 
 year. 
 
 He contracted with parties to build three looms, they to pay a certain price for the invention, but be- 
 fore this contract was fulfilled on either side, he visited New York, and there saw for the first time a 
 new and different species of counterpanes, then just introduced from England, which, from the superior- 
 ity of the fabric, he perceived must soon supersede the knotted counterpanes. Although being at that 
 time in great pecuniary want, and surrounded by all its attendant privations and temptations, instead 
 of proceeding to the enforcement of his contract, which would have at once relieved his wants, he im- 
 mediately returned to Boston, and communicated to the parties what he had seen and believed, and 
 advised them to abandon the enterprise, as, in his judgment, the new kind of fabric would be preferred 
 in the market, and that he could produce a loom which would weave it with greater facility than the 
 knotted counterpanes could be woven. His success in his first effort of invention, and the honesty of 
 purpose manifested in this his first business transaction, could not fail to inspire a degree of confidence 
 in his ability and integrity which proved of great advantage throughout his subsequent life, in bringing 
 all his enterprises to a successful issue. 
 
 He now entered into an agreement with the same parties to invent an automatic loom for weaving 
 this new species of counterpanes, which was afterwards produced, and patented on the 24th of April, 
 1840, and put in successful operation. There are now 36 of these looms in operation at Clinton, Massa- 
 chusetts, which supply the principal demands of our markets. 
 
 Before he had completed the counterpane-loom above described, he had incidentally seen in New 
 Jersey the operation of weaving coach-lace in hand-looms, and not having as yet realized any pecuniary 
 advantage from his efforts, he determined, while progressing with the new counterpane-loom, to direct 
 his attention to the subject of weaving coach-lace. With this view, he made inquiries of persons en- 
 gaged in vending this kind of fabric, as to the extent of the consumption and the cost of production, as 
 well as the difficulties of weaving it by hand. The result of his investigation determined him to make 
 the attempt, and, with the pecuniary assistance of an elder brother, he proceeded to the construction of a 
 loom which was completely successful. So urgent were his necessities at this time, and such was the 
 ardor with which he pursued the subject, that he labored day and night, scarcely taking time for food 
 and rest, and in the short space of six weeks from the time that he made the inquiries above referred 
 to, he had the first loom in operation, and in three months after that, another and more perfect one, and 
 the requisite capital under his control for putting up a large establishment. This result, when we con- 
 sider the youth and inexperience of the inventor, and the peculiar difficulties of the subject, seems to 
 us to have no parallel in the history of inventions. 
 
 The figure on coach-lace is produced by raising on the surface of the ground-cloth a pile similar to 
 the Brussels carpet, formed by looping the warps over fine wires, which are inserted under such of the 
 warps as have been selected by the jacquard to determine the figure. The warps are then woven into 
 the body of the cloth, to tie and fix the loops. The wires are then withdrawn and re-inserted. Auto- 
 matic pincers, as if instinct with life, grasp the end of the wire, draw it out from under the forward 
 loops, carry it back towards the lathe, where the warps are spread apart, forming what is called the 
 open shed, and there introduce and drop it, that the shed may be closed and opened, that by the throw 
 of the shuttle, the weft-threads, which are to tie and weave the warp-threads into the cloth, may be 
 beaten up by the reeds. The pincers then move back to draw another wire from under the formed 
 loops, and repeat the same operation, several such wires being used at the same time in the cloth, to 
 prevent the loops from being drawn out by the tension which is given to the warps to insure an even 
 and regular surface to the fabric ; but as there are a number of these wires woven into the cloth, nearly 
 touching one another, it became a matter of great difficulty to contrive a mechanism winch would in- 
 sure the taking of only one of these wires to draw it out, and select the piroper one at each operation. 
 The pincers could not practically be made so narrow, and work so accurately, as to insure this. This 
 difficulty was overcome by an ingenious mechanism placed on the opposite side of the loom, which at 
 each operation selects the required wire, and pushes it out sufficiently far beyond the ends of the 
 others to be gripped by the fingers, which then draw it out to carry it back and introduce it in the open 
 shed of the warps. 
 
 Some notion can be formed of the difficulties which this subject presented, by taking into considera- 
 tion that the mechanism which works the wires must operate in connection with the mechanism which 
 weaves the cloth, and the jacquard which produces the figure. 
 
 The cost of weaving coach-lace was very much reduced by this invention, and there are now in one 
 establishment in Clinton, Massachusetts, 96 of these looms in successful operation. 
 
 Soon after this was in successful operation, Mr. Bigelow completed his second counterpane-loom, to 
 which we have before referred, and he had then accomplished the first purpose which impelled him to 
 exercise his ingenuity — he had acquired the means of completing his medical studies. But by this 
 time he had found much greater attractions in the new career which circumstances had opened before 
 him — it was one for which nature had manifestly intended him, and therefore invention was an occuna- 
 
LOOM, CARPET WEAVING. 
 
 298 
 
 tion no longer ancillary, but paramount, and the success with which he has pursued it up to this day L- 
 now distinctly marked upon the pages of our industrial history.* 
 
 The coachdace loom was merely the basis of a series of improvements then contemplated, but 
 which have since been completed, and are now in successful use ; these improvements are in looms foi 
 weaving Brussels and tapestry carpeting. , 
 
 The weaving of Brussels and tapestry carpets by automatic machinery was considered by many, a 
 few years back, to be a mechanical impossibility, and, indeed, there were few subjects that presented 
 such formidable difficulties. After constant anti laborious exertions, at times snatched from other 
 pressing engagements, Mr. Bigelow succeeded also in this undertaking. There are now 28 Brussels 
 looms in operation in one establishment in Clinton, producing carpets which are pronounced by the 
 ablest judges to be the best Brussels carpets manufactured in any part of the world, and 50 tapestry 
 looms in the establishment of Messrs. Higgins & Co., New York; and when those now in contempla- 
 tion shall have been completed, there will be 225 looms in operation on his plan, weaving each, on the 
 average, from 18 to 20 yards per day, while from 3 to 4 yards per day is tiie average product of hand- 
 looms. 
 
 The surface of the carpets woven by these looms is more perfect and regular than when woven by 
 hand, the texture of the cloth more regular, and, what is of the greatest importance, the figures are so 
 regularly measured that, when put together, they make a perfect match. This perfection in the quality 
 of the cloth and the regularity of the figure is in part due to improvements which will be described in 
 connection with the ingrain-loom, as they are applicable to the weaving of all kinds of figured fabrics 
 that require regularity in the figure. 
 
 Shortly after the completion of his coach-lace loom, Mr. Bigelow called on Mr. Alexander Wright, the 
 agent of the Lowell Manufacturing Company, who was not only a man of great experience in manu- 
 factures generally, but possessed an intimate knowledge of the manufacture of coach-lace. From him 
 he obtained valuable information, and in the course of their conversation, Mr. Wright called his atten- 
 tion to ingrain carpets, and suggested to him the importance, as well as the difficulty, of producing a 
 power-loom for weaving that kind of fabric. The hint was not thrown away, for as soon as he had 
 completed his second counterpane-loom, he bent his mind to improving the ingrain manufacture, and in 
 the year 1839, through the instrumentality of Mr. Wright, entered into an agreement with the Lowell 
 Manufacturing Company to accomplish this purpose, and before the close of that year had completed 
 the first power-loom for weaving two-ply ingrain carpets. This loom produced from 10 to 12 yards per 
 day — the hand-loom produced only 8 yards per day. 
 
 When his mind was first turned to this subject, it presented these leading difficulties. The mere 
 weaving of the fabric by an automatic loom was easily effected, but to invent a loom which should make 
 carpet fast enough to be economical, one which should make the figures match, and to have a good and 
 regular selvage and a smooth, even face, were very serious practical difficulties. The hand-weaver, by 
 the exercise of his judgment, can, to a certain extent, meet these contingencies ; if the weft-thread is too 
 loose after the shuttle has been thrown, he can give it a pull with the fingers to make the selvage reg- 
 ular; if he finds by measurement that by reason of the irregularity of the weft-threads or the ingrain- 
 ing, the figure is being produced too long or too short, he gives more or less force to the lathe in beating- 
 up ; and if he finds that the surface of the cloth is getting rough, he regulates the tension of the warps. 
 In this way, by observation and the exercise of skill and judgment, lie can approximate, and only ap- 
 proximate, to the production of a good and regular fabric. But to invent an organization of matter 
 which should itself observe, and think, and judge, and do it all with more unerring accuracy than man 
 himself- — this was a result almost absurd to contemplate, but which it was reserved for Mr. Bigelow 
 to attain. 
 
 In the first loom produced, he approximated more nearly than the hand-weaver to a perfect match in 
 the figure, and this he effected by taking up the woven cloth by a regular and positive motion which 
 was unerring, the same amount for every throw of the shuttle and beat of the lathe, and as the weft- 
 threads are not spun regularly, and the weaving in of the warp-threads and passing the different colors 
 from the upper to the lower ply or cloth, (as ingrain carpets are composed of two or three cloths woven 
 and connected together,) to produce the figures, requiring sometimes more and sometimes less to make 
 a given length, he determined to regulate the delivery of the warps as required by their tension, thereby 
 throwing the irregularities into the thickness, where it cannot be noticed, instead of in the length, where 
 it would destroy the match of the figures. And lie accomplished this by suspending a roller on the 
 woven cloth, between the lathe and the rollers that take up the woven cloth, so that when the cloth 
 was being woven too short, which indicates a deficient supply of warps, the roller would be elevated, 
 and by its connection increase the delivery motion to give out more warps ; and when the cloth was 
 being woven too long, which indicated too great a supply of warps, the roller was let down to decrease 
 the delivery motion, and thus reduce the supply of warps. In this way the roller was made to act as 
 a measurer and feeler of the quantity of warp demanded, and to direct the supply. But this contri- 
 vance, like the mind of the hand-weaver, only came in play to prevent the progress of an evil after it 
 had been observed. If he had applied this yielding roller to the unwcven warps to feel and ascertain 
 the demand of warp beforehand, lie could have prevented the evil. He did not then perceive that this 
 could be done, for the reason that this roller must be sensitive to detect and indicate the amount, and 
 at the time the lathe beats up the weft, the warps must be rigid to resist the beat, or else a good fabric 
 cannot be produced. This was, however, accomplished by a subsequent improvement, which will be 
 hereafter described. 
 
 * In addition to the establishments at Lowell, Thompsonville, and other places which have been built solely for the use 
 of his improvements, the new town of Clinton, Massachusetts, (which we have mentioned before,) situated twelve miles 
 north of Worcester, and now containing a population of nearly 3000, is virtually the creation of Mr. Bigelow’s own mind, 
 it having been built up by business consequent upou his inventions. 
 
294 
 
 LOOM, CARPET-WEAVING. 
 
 A smooth and even surface for the cloth he obtained in the following manner. We have already 
 pointed out that the passage of the warp-threads from one ply or cloth to the other, called ingraining, 
 must necessarily be unequal and depending on the figure to be produced, and that in consequence of 
 this the warp-threads that are the most ingrained will be taken up faster than those less ingrained, and 
 as all the warps are of necessity rolled up on the warp-beam with equal tension, they can only be given 
 out equally. 
 
 This seeming impossibility he did effectually overcome in the following manner. Each warp-thread 
 in the usual way passes through a loop called a mail, attached to a card suspended from the jacquard, 
 and each card has suspended to it a weight, all the weights being equal. The two trap-boards of the 
 jacquard move simultaneously, one up and the other down, and in these movements they catch or trap 
 such of the cords (determined by the combination of cards) as are required to bring up the proper warp- 
 threads at each operation to produce the figure, leaving down such of them as are not required at that 
 particular operation ; and when the two trap-boards are on a level, and all the warp-threads connected 
 with them in a horizontal line, and those not connected with them hanging down with the weights sus- 
 pended to them, the lathe beats up the weft-thread which lies between the warps that are in a horizon- 
 tal line, at the same time exerting a force on the weft-threads previously thrown, and beating them up 
 more closely. 
 
 Now, as the warp-threads are all connected at one end to the woven cloth, and at the other with the 
 beam, it follows that those which are hanging down in a bent line with the weights suspended to them, 
 will receive a greater proportion of the force of the beat of the lathe than those which are in a straight 
 line ; and as all the warp-threads in succession take this hanging-down position, and all of them have 
 an equal weight, it follows necessarily that each warp-thread in succession receives the same pull at 
 the time the lathe beats up, and that therefore all tendency to irregularity in the length of the warp- 
 threads taken up by the ingraining will not tend to produce an irregular surface, but, on the contrary, 
 the surface of the cloth will be as smooth and even as if all the warp-threads were equally taken up 
 in the weaving of the cloth, and were under a constant and equal tension. 
 
 At the same time he accomplished the making of a good selvage by a mechanism which handed in- 
 stead of throwing the shuttle across — an arm carried the shuttle half way across, and another there took 
 it and carried it entirely across. By this means any required degree of tension could be given to the 
 weft to make a smooth and even selvage. But although it accomplished this desirable object, it failed 
 to work with sufficient velocity, and thereupon Mr. Bigelow, nothing daunted, renewed his efforts, and 
 produced another loom with the fly-shuttle, in which he was enabled to make a good selvage by a 
 mechanism which gives a pull to the weft-thread after the shuttle has been thrown, and as the lathe 
 beats up. He also introduced other improvements, which will be hereafter described. This loom, 
 although it produced about 18 yards per day, did not satisfy the inventor, and he again applied himself 
 with renewed energy until he made a third loom, which averages from 25 to 27 yards per day of two- 
 id y, and from 17 to 18 of three-ply carpets. There are now in operation at Lowell, Thompgonville, and 
 t’nriffville, 450 of these improved looms. 
 
 This brings us to our main purpose, the description of the loom as it is now worked, with all the 
 improvements which have been made in succession from the commencement to the date of the last 
 patent, the 23d day of October, 1849. But before proceeding to the detailed description of this loom, 
 it may bo well to state that the improved method of producing figures that will match, which makes 
 part of this loom, was invented in 1844, and patented on the 10th of April, 1845, in connection with a 
 loom for weaving plaids and ginghams, which has gone into extensive use at Clinton, there being now 
 580 of them in one mill, and 120 in another. 
 
 In addition to the various important inventions which have been enumerated, many others have been 
 made by Mr. Bigelow connected with the details of various kinds of looms, and for drying and stretching 
 fabrics and printing warps, some of which have been, and others are to be, patented both in England 
 and in this country, and which are nearly all of decided practical utility. No one man within our 
 knowledge, either in Europe or in this country, has given to the world so large a number of valuable 
 inventions as Mr. Bigelow, and inventions, too, evincing not only great ingenuity, but sound inductive 
 powers of the highest order. 
 
 This invention for weaving ingrain carpets, taking it from the commencement, through all its stages, 
 to the date of the last patent, consists : 
 
 1. In operating the trap-boards of the jacquard in a power-loom simultaneously, one up and the other 
 down, instead of moving them alternately as in the hand-jacquard, whereby either the time required 
 for the movements of the jacquard, or the velocity of their motion is reduced, the former admitting of 
 more expeditious weaving (if the other operations be accelerated in the same ratio), and the latter re- 
 ducing the liability to wear and tear. But there are other and important advantages incident to tnis 
 change, such as balancing the weight of the harness, which in a jacquard is considerable, for that part 
 of the harness suspended to the descending trap-board balances the corresponding harness suspended 
 to the ascending trap-board, thus equalizing the resistance to the moving power, and rendering the 
 operations easier and more regular. And still another change is, that the beat of the lathe takes place 
 after the warps connected with the two trap-boards have passed and are a little crossed, and whilst the 
 remaining warps are in their lowest position, that is, bent down by the weights suspended to their trap- 
 cords, so that these, which like the others are held at both ends and bent down, will receive a greater 
 portion of the force of the beat of the lathe ; and as all the warps in turn take this position, and each 
 warp-thread, when in this position, is held down by the weights — all of them equal — suspended to its 
 trap-cord, it follows that all the warp-threads, as before stated, receive an equal tension in beating-up 
 the weft-threads, no matter what may be the variation in their lengths between the woven cloth and 
 the yarn-beam, occasioned by the irregularity of the ingraining. The practical weaver will appreciate 
 this as one of the most important advantages in weaving ingrain carpets, for it presents a principle ot 
 '.ompensation and self-adaptation to the irregularity of the ingraining due to the figure never before 
 
LOOM, CARPET-WEAVING. 
 
 295 
 
 attained, and by which alone such fabrics have been made with a regular and measured figure, having 
 a face or surface as smooth and even as a plain fabrie. 
 
 2d. In taking up the woven cloth by a regular and positive motion, which measures the length of 
 cloth to be produced at each beat of the lathe when employed in connection or combination with a 
 method of regulating the delivering out of the warps by their tension in proportion to the quantity re- 
 quired, and taken up in the process ef weaving, and also with the holding of the warps rigid at the time 
 the lathe beats up the weft to prevent them from yielding to the force of the beat. It will be seen that 
 m this way the irregularities of the ingraining and of the weft-threads will be thrown into the thickness 
 instead of the length of the cloth, for as the lathe beats up the weft-threads to the same distance each 
 time, and a given and measured length of cloth is taken up, the same length of cloth will be woven ; 
 but if the warp-threads were free to yield at the time the lathe beats up instead of forcing up the weft- 
 threads to the required position, the whole cloth and warp would be forced forward, and produce what 
 is called a sleazy fabric ; and this, from its loose texture, would soon accumulate to such an extent as 
 to stop the further progress of weaving. But to prevent this, the moment the lathe begins to beat up 
 the weft-thread, the warps are held firm to resist the force of the beat, and thus insure the carrying of 
 the weft-thread up to the required line. In this way the two opposing or antagonistic conditions — sen- 
 sitiveness to deliver out the quantity required, whatever may be the irregularity of the demand, and 
 non-yielding to resist the beat of the lathe — are reconciled to produce the important result of weaving 
 ingrained fabrics with a regular and measured figure ; a result never before attained, even with the 
 hand-loom. 
 
 3d. In mounting the shuttle-boxes in independent frames at the sides of the lathe, which in this way 
 becomes a mere guide to the shuttles as they are thrown from one side to the other. The advantages 
 of this arrangement are, first, the weight of the lathe (which must have a considerable range of motion 
 and a high velocity) is greatly reduced, and will not, therefore, require so much power to operate it ; for 
 in weaving two and three ply carpets, particularly such as have a variety of colors, the shuttle-boxes 
 are numerous and heavy, and in proportion to the number and weight would be wasteful of power and 
 liable to derangement if carried by the lathe. Secondly, it affords a surer, easier, and more durable 
 mode of operating the shuttle-boxes to shift the shuttles for the changes in the colors of the pattern , 
 and, lastly, it is very efficient in producing a good selvage, for the moment the shuttle is thrown the 
 weft-thread is held on a permanent bed by fingers, so that as the lathe beats it up, the pressure of the 
 fingers affords the required friction to pull the weft-thread to make a tight and regular selvage ; and 
 the shuttle-boxes being in independent frames, the weft-thread is not drawn out of its position in the 
 cloth by the back movement of the lathe, as in the ordinary loom. Thus, the weft-threads, when once 
 beaten up, are retained in that position, and their parallelism in the cloth is insured. 
 
 4th. In connection with the mounting of the shuttle-boxes in independent frames by the side of the 
 lathe, using one cam and roller to work the lathe, and another to hold it in a fixed position during the 
 throw of the shuttle, one of the said cams being on the lathe-shaft, and the roller which works in con- 
 nection with it on the lathe, and the other cam on the lathe, and its roller or wrist attached to the first 
 cam ; one of the cams being concentric to hold the lathe in a fixed position during a part of the rotation, 
 and whilst the shuttle is being thrown, with its ends eccentric, that the roller may enter and leave it as 
 the lathe is either gradually started or gradually arrested, and the other cam being of any form suitable 
 for giving the lathe the required varying motions. 
 
 By this means the cam and roller, which operate the lathe, and which are, in consequence, exposed 
 to all the strain and wear and tear, are not used to hold the lathe in a fixed position during the throw 
 of the shuttle. 
 
 5th. In combining with a power or automatic loom four series of shuttle-boxes, two on each side in 
 separate frames at the sides of, and independent of the lathe, the said four series of shuttle-boxes 
 receiving motion from the loom or from some first mover in connection with, or operating in unison with 
 the loom ; one series of these shuttle-boxes on one side being for the purpose of holding all the shuttles 
 of the various colors required for one ply of the carpet, and the corresponding series on the other side 
 to contain the shuttles of the various colors for the other ply, so that by the up and down motions of 
 these boxes, the various changes of colors can be effected, the other two series of shuttle-boxes being 
 merely to receive and return the shuttle from and to the first series. In view of this, for some patterns 
 the second or receiving shuttle-boxes may be single ; but for others they are required to be double, as 
 the colors are required to be alternated. 
 
 6th. In combining with the lathe and the shuttle-boxes in separate and independent frames by the 
 sides thereof, hinged guides to guide t]^ shuttles from the one to the other, and to yield and thereby 
 prevent breaking whenever a shuttle, ot any part of it, fails to enter the shuttle-boxes. 
 
 7tli. In giving to the jacquard, which determines the figure, a separate organization independent of 
 the loom which forms the cloth, that the various motions of the jacquard may be taken from or given 
 hy a shaft or shafts within it, and simply deriving its or their motions from some part of the loom, or 
 from some first mover corresponding with or regulated by the motion of the loom or part thereof, that 
 the motions of the jacquard may correspond with those of the loom. In this way the motions of the 
 jacquard are rendered more accurate and steady, and the weight of the moving parts is greatly reduced. 
 
 Prior to this invention, in all looms for weaving by power in connection with the jacquard, all the 
 motions of the jacquard were derived directly from some part of the loom and communicated by con- 
 necting-rods, which were necessarily of great length. The principal difficulties attending this old mode 
 of construction and organization were the inaccuracy of the motions by reason of the great length of the 
 connecting-rods, the liability to derangement, and the labor and difficulty of adjusting the connections to 
 the varying lengths of the cords of the harness as they are affected by atmospheric changes. All of 
 which difficulties are avoided or greatly reduced by this separate organization. 
 
 8 th. In making the whole frame of the jacquard adjustable at one operation relatively to the frame 
 of the loom, that the distance between the two may be adjusted to the varying lengths of the cords oi 
 
2665 
 
 296 
 
 LOOM. CARPET- WEAVING. 
 
LOOM, CARPET-WEAVING. 
 
 297 
 
 the harness, whereby the utmost nicety in the adjustment can be obtained, and at the same time, in con- 
 nection with the separate organization, avoiding the necessity of adjusting the connections when it be- 
 comes necessary to adjust the jacquard to the varying lengths of the cords of the harness, for the 
 jacquard, having a separate organization, no change becomes necessary in its own connections. 
 
 9tn. In communicating the required motions to the picker-staffs and to the apparatus for shiftily the 
 shuttle-boxes hung in pendulous frames at the sides of and independent of the lathe, from a shaft or 
 shafts above, whereby is avoided the serious difficulty before experienced of communicating the motions 
 
298 
 
 LOOM, CARPET-WEAVING. 
 
 from a shaft or shafts below to the picker-staff and the apparatus for shifting the shuttle-boxes which 
 must be attached to or connected witli the shuttle-box frames that vibrate on axes above. By this im 
 proved arrangement the motions are derived from a shaft or shafts coincident with or near to the axis 
 of motion of the pendulous frames that carry the shuttle-boxes, instead of being below, where the frames 
 have the greatest motion. 
 
 10th. In introducing in power-looms a reversing motion. Before this, power-looms were simply pro 
 vided with the means of disconnecting the motive power, and arresting the momentum of the moving 
 parts to enable the attendant to piece the threads, or to do what might be necessary preparatory to 
 re-starting ; but as the loom cannot always be stopped with the parts in the positions required, the 
 
LOOM, CARPET- WEAVING. 
 
 299 
 
 ittendant has to reverse the motion of the loom by the application of hand-power to the driving-pulley , 
 a mode of procedure attended with waste of time and great inconvenience, for the attendant must leave 
 L’is usual position to go to the driving-pulley, and in heavy looms, such as are used for weaving carpets, 
 much strength is required to set the machinery in motion. But by the use of a reversing motion, the 
 attendant, without leaving his place, and by the simple motion of a lever, can operate the mechanism 
 in either direction and to any extent desirable to bring the parts to a proper position for piecing the 
 threads, &c., and re-starting. 
 
 In the accompanying drawings, Fig. 2G65 is a plan of the loom in the present improved form. 
 
 Fig. 2666, a plan of the loom below the jacquard. 
 
 Fig. 2667, a front elevation ; Fig. 2668, a back elevation. 
 
 Fig. 2669, an elevation of the left-hand side, without the jacquard; Fig. 2670, a vertical section, with 
 the jacquard ; and Fig. 2671 another section. 
 
 In the said drawings, A represents the power-loom, and B the jacquard-frame resting on beams 
 C C C' O', supported on columns D from the main floor. 
 
 The pendulous frames E E, which carry the series of shuttle-boxes, are arranged on each side of the 
 lathe, and independent thereof, and are hung on arbors F F, at the top, on which they vibrate. These 
 frames are vibrated back and forth simultaneously, in opposite directions, at each throw of the shuttle, 
 so that the first series of shuttle-boxes on one side, and the second or receiving boxes on the other, shal 1 
 
 oe in line with the race-beam of the lathe when one shuttle is thrown, and vice vena for the next tnrow 
 And these motions are obtained from a cam A' on the main cam-shaft B’ of the loom, which acts on an 
 arm C s of a rock-shaft D that extends across the loom. This rock-shaft carries at each end a cogged 
 sector E , which engages a pinion F' on a short arbor G' (one on each side) which carries two cranks 
 U , one at each end, the wrists of which are fitted to grooves I’ I' in the pendulous frames, so that as the 
 
300 
 
 LOOM, CARPET- WEAVING. 
 
 arbors G' G' are vibrated by the rotation and peculiar form of the cam A' and the connections, the 
 pendulous frames are vibrated in opposite directions, and there held during the throw of the shuttle, 
 and then back again. 
 
 The driving-shaft a of tire loom has a fast and loose pulley b c on one end, which receives the driving- 
 belt from any first mover in the usual way ; and on the other end the said shaft has a bevel-pinion d. 
 
 which takes into and drives a bevel-wheel c on the lower end of a line-shaft f which extends up to and 
 has its upper bearing in a box g attached to one of the beams C', the upper end of the said shaft having 
 a bevel-pinion h, which engages and carries a bevel-wheel i on one end of a horizontal shaft j, which has 
 its bearings in boxes attached to the tops of the beams C. It is from this horizontal shaft that all the 
 jacquard and shuttle motions are taken. 
 
LOOM, CARPET- WEAVING. 
 
 301 
 
 On this shaft j there is a cogged wheel R which communicates motion to a cog-wheel i on the jac- 
 quard-shaft m, by the medium of a connecting pinion n, which turns on a stud-pin o adjustable in a 
 sector-mortice p, the curve of which is struck 'from the centre of the shaft m. that the pitch-line of the 
 said connecting pinion may be always at the same distance from the axis of the wheel i, when its stud- 
 pin is shifted. By this means, when the jacquard-frame is adjusted, the connecting pinion can also be 
 shifted and adjusted relatively to the pinion k on the shaft j. 
 
 The frame B of the jacquard, as already intimated, instead of being permanently attached to the 
 -beams C' O', is free to slide vertically, for the purpose of vertical adjustment, to suit any change in (lie 
 length of the harness. The side-pieces q q of the frame of the jacquard embrace the transverse beams 
 C' C', and slide in them accurately, but freely. 
 
 The jacquard-frame rests on two horizontal slides S S, which are adapted to slide on the transverse 
 beams (7 C', the upper surfaces of each being formed with two inclined planes 1 1, one for each of the 
 sides of the jacquard-frame to rest on, so that when these two slides are moved to the one side or the 
 other, the entire jacquard-frame will be elevated or depressed relatively to the loom below, the stud-pin 
 of the connecting pinion n being at the same time adjusted in its sector-mortice to adjust the pitch-line 
 of the cogged geering. The slides S S are operated simultaneously by a hand-wheel «ona short arbor 
 v in front, which carries a worm w that engages the cogs of a wheel *on a shaft y that carries two 
 pinions z (only one shown in the figures) that engage the cogs of a rack a on each of the slides. 
 
 For the purpose of adjustment, it is only necessary to turn the hand-wheel until the jacquard is 
 
 brought to the required position, and then to adjust the geering by shifting the stud-pin of the connecting 
 pinion, the thread of the worm on the hand-wheel arbor and the inclination of the wedges being suffi- 
 cient to retain the parts in a permanent position. 
 
 The required motions of the trap-boards b' and c, and the journals d' e f g, are derived from the 
 jacquard-shafts m, which, as described above, receive a continuous rotary motion from the driving-shaft 
 
302 
 
 LOOM, CARPET- WEAVING. 
 
 of the loom below, and the proportions of the geering, as represented in the figures, should be such as 
 to give to the jacquard-shaft one revolution for every two of the lathe-shaft of the loom. On each end 
 of the jacquard-sliaft m there are two cams K K and i i', which are all of the same form as represented 
 in the figures. The cams h' h' are placed on opposite ends of the shaft, and in corresponding positions 
 to work the trap-board b', and the other two cams i' i are arranged in the same manner, but on the 
 opposite side of the axes of the shaft m, to operate the other trap-board c , as one trap-board descends 
 whilst the other ascends ; and the form and position of the cams should be such that one trap-board 
 shall begin to ascend as the other begins to descend. There are four levers j'j'k'k' placed above the 
 cams and operated by them, each lever being hung on a fulcrum-pin at the rear of the frame, and having 
 a roller m which bears on the cam. The two levers// are connected with the ends of the trap-board 
 U by connecting-rods in’ m\ that the cams liK may communicate the required motions to it; and the 
 
 other levers k’ k' are in like manner and for the same purpose connected to the other trap-board o', by 
 similar rods n n. In this way it will be perceived that the required alternate up and down motions 
 are given to the two trap-boards. The same cams and levers are employed for operating the four 
 journals d' e' f <j . The two journals are alternately elevated with the trap-board b' , and the other two 
 f </ are in like manner operated with the other trap-board c, which is effected in the following manner : 
 To the ends of the four levers/ and k’ are jointed four rods o' o' o' o', (one to the end of each,) the upper 
 ends of which play in slots p p' p p in the top plate q of the jacquard-frame — these slots being of such 
 length that the rods can vibrate sufficiently to pass from one journal to the other. The upper ends 01 
 these rods are rounded, and enter sockets in the under face of the ends of the journals, so that when 
 brought under either of the journals, when the levers are raised by the cams, the journals will be ele- 
 vated. As there are two journals for each trap-board, and these are alternately elevated with the 
 sorresponding trap-board, the lifting-rods must be alternately shifted from the one to the other. As the 
 
LOOM, CARPET- WEAVING. 
 
 30-3 
 
 rods are so jointed as to incline outwards, when vibrated they will fall, by gravity, against the outer 
 ends of the slots p, which are so located as to hold the rods in a position to catch under the two outer 
 journals d ang g. 
 
 In this position, when either of the trap-boards are elevated, one of the journals will be carried up 
 with it; but when the other journals are to be lifted, the rods o' are to be shifted from the outside jour- 
 nals to the inside ones, and this is effected by cams r r s' s, two on each side of the frame, and on one 
 
 and the same shaft t', receiving motion from the shaft to' by two cog-wheels, u v. These four cams are 
 all of the same form as represented in the plates, and arranged in two sets, one of each set being on 
 each end of the shaft, and the position of the two sets relatively to each other will depend upon the 
 form and position of the levers which they operate. On each side of the frame there are two levers, 
 in x, (the two sets corresponding in every particular,) that vibrate at y' on the same arbor, the one w of 
 which bears by the disposition of its weight on the periphery of one of the cams r, and the other x on 
 one of the cams s'. The arm of each of these levers acts against one of the rods o', so that there is one 
 Buch lever and cam for each rod o' ; and as the shaft t’ of these cams makes but one rotation for every 
 
304 
 
 LOOM, CARPET-WEAVING. 
 
 two of the jacquard-shaft, the levers w' and x will act upon the corresponding rods o' at every alternate 
 descending motion of each trap-board. 
 
 The form of the cams r' and s' is such that during one rotation of the jacquard-shaft m, they elevate 
 one set of levers w w, to shift the two corresponding rods o' o' from one journal to the other, and during 
 the next rotation of the jacquard-shaft they recede to permit these rods to fall back, whilst the other 
 set of levers x x' shift the other two rods o' o' from one to the other of the other set of journals, the 
 next rotation liberating these and shifting the first set. In this way it will be seen that during one 
 operation, when the trap-board c descends, the journal g descends with it, the trap-board b' at the same 
 time being carried up and down with the journal e'. At the end of this motion the cams r r throw out 
 the levers w w, which shift the rods o' o' to the journal /'; at the next operation the trap-board c is 
 
 elevated, and with it the journal /', the trap-board b' at the same time descending, and with it the 
 journal e, and when this has reached the end of its down motion, the rods o' o' continue the motion 
 down sufficiently to clear the sockets of the journals, and then by their own weight the rods fall back 
 to the journal d', to be ready to carry it up at the next upward motion of the trap-board b ' ; and when 
 this takes place the trap-board c descends, and with it the journal/', at the end of the down motion of 
 which the rods o' o' fall, to come under the journal g\ so that at the next upward motion of the trap- 
 board c, this journal may be elevated, during which the trap-board b' descends, and with it the journal 
 d and when this is entirely down, the cams s' s' act upon the levers x x, which shift the rods o' o' to 
 the journal e. Thus the journals d' and e are alternately carried up and down with the trab-board b’ 
 and the other two journals/ and g' with the trap-board c. 
 
 The journals of the card-prism a? (of the usual construction) are hung in the rods P P, which slide 
 horizontally on the sides of the jacquard-frame, and which at the back are jointed to two arms c 2 c 2 in 
 a rock-sliaft d 2 , from which projects another arm e 2 , connected by a rod f 2 with a treadle g 2 that vibrates 
 
LOOM, CARPET-WE AVIN (}. 
 
 305 
 
 on a fulcrum-pin at the back, its front end being provided with a weight h 2 of sufficient gravity to push 
 out the prism, the levers being elevated to draw in the prism by a cam i 2 on the jacquard-shaft m. 
 The form of the cam i 2 , and its position relatively to the trap-board cams, must be such as to bring the 
 prism into action while the trap-boards are at rest. 
 
 The straps k 2 k 2 k 2 k 2 of the picker-staffs / 2 j 2 extend up to, and are secured each to a picker-lever P, 
 there being two such levers on each side, which are jointed at their back end to the upper arm nP ot 
 two levers iP n 2 that vibrate on a stud-pin o 2 attached to one of the beams 0. 
 
 The levers iPiP constitute each two arms, at right angles with the arm in 2 the back one carrying a 
 weight/) 2 which must be sufficient to carry back the picker-lever P, and the forward end carries a 
 roller q 2 which bears up against the periphery of a cam-wheel r 2 , so that when the roller bears on the 
 periphery of this wheel, the picker-lever is pushed and held forward to the full length of its longitudi- 
 nal motion ; but when, by the rotation of the wheel, the roller is permitted to enter a depression in its 
 periphery, the picker-lever is drawn back. As stated above, and as represented in the plates, there 
 are two picker-levers on each side, one for each picker-staff, and, therefore, two inverted T levers rn? n‘, 
 and one cam-wheel r 2 , for each lever rrP rP. The forward ends of the picker-levers P work between verti 
 cal guides s 2 , to prevent lateral play, and they are each provided with a hook P, which, when the lever is 
 drawn back, hooks into the end of the picker-treadle u 2 , which is made of sufficient breadth to receive 
 and operate the two, there being one treadle on each side, and operated at the proper periods of time 
 by two cams v 2 v e , one for each treadle, and placed on opposite ends of the shaft /', as before described. 
 
 Each cam has two projections opposite to each other, so as to operate the treadle twice for each ro- 
 tation, and the projections of the two cams are placed in the same line, so that the two treadles are 
 operated at the same time, and the shaft makes one rotation for every two beats of the lathe of the 
 loom ; hence the treadles are both worked once for each beat. This simultaneous working of the trea- 
 dles is rendered necessary, because two shuttles have frequently to be thrown in succession from the 
 same side. As both treadles are operated for each beat of the lathe, and there are two picker-staffs 
 on each side, at each beat of the lathe one of the picker-levers P must be put in connection with one of 
 the treadles, whilst the other remains disconnected. This is effected by drawing back the picker-lever 
 which is to be operated, until its hook catches into one of the treadles, and this must be done whilst 
 the treadle is down, and at rest. The manner in which the picker -treadles are drawn back to effect 
 the hooking on to the treadle has already been described, as also the manner of pushing them forward 
 to carry their hooks beyond the range of motion of the treadles, and it only remains to explain 
 how the succession is determined. This is done by means of four cam-wheels r 2 , which act on 
 the four levers rP vP, as described above. These cam-wheels are formed with a series of cam-like 
 depressions v? made at equal distances around the periphery, into each of which the rollers of the 
 levers rP enter; and when this takes place, the weights on the levers n 2 draw the picker-levers so far 
 back that the treadles in rising catch under the hooks and elevate the picker-levers, and the further 
 rotation forces out the rollers from the cam-like depression on to the periphery of the circle of the 
 wheels, which forces the picker-levers so for forward as to disengage the hooks. There must be as 
 many of these cam-like depressions in each cam-wheel as the number of changes of shuttle required 
 in the kind of fabric to be woven ; eight being the number represented in the plates for eight changes 
 of shuttle. To each of these depressions is fitted a block, which when put in renders the periphery of 
 the wheel cylindrical ; and when all are in, the picker-levers will not be engaged or hooked by the 
 treadle, and hence no shuttle will be thrown ; and, therefore, in setting the loom for any particular 
 kind of fabric, the operator will leave out of each of the cam-wheels as many of these blocks, and in 
 the order required, as may be necessary for operating the picker-staffs in the order required for the 
 succession of the shuttles. The four cam-wheels r' 2 are on a shaft x 2 , parallel with, and receiving motion 
 from the shaft/, by a cog-wheel and pinion y" 2 z 2 , the shaft x 2 making one rotation for four of the shaft 
 j. The plates represent the back, or receiving shuttle-boxes c 3 c 3 , as consisting of two on each side, 
 although for some kinds of fabrics but one is required, in which case they are not required to be oper- 
 ated in the pendulous frames. When the two are used on each side, they are adapted to slide in the 
 back of the pendulous frames, and are suspended each to one end of a lever b 3 , by a connecting-rod d 3 , 
 the rear end of the said levers being provided with a sufficient weight e 3 to lift the boxes, in order to 
 bring the lower box of the series in line with the race-beam of the lathe ; and when the upper box is 
 to be let clown to receive a shuttle, the weighted end of the lever is elevated by a cam a 3 on the end 
 of the shaft re 2 , before described as carrying the cams to determine the succession of the motions of the 
 picker-staffs. The form of the cams a? will of course depend on the pattern to be woven, and as they 
 are on the ends of the shaft, they can be removed and other cams of different forms substituted. The 
 front series of shuttle-boxes f 3 f 3 are represented as consisting of twelve shuttle-boxes on each side, 
 adapted to work patterns requiring twenty-four shuttles. As the two series are operated in like man- 
 ner, it is only necessary to describe one series. 
 
 These shuttle-boxes f 3 are all connected together, and slide in the front of the pendulous frame, and 
 are suspended to a chain a° that is attached to and winds on a barrel b 6 on the arbor F of the pendu- 
 lous frame; and this arbor carries another barrel, on which winds another chain c 6 that passes over a 
 guide-pulley, and has a counter-weight d 6 suspended to it to counterbalance the shuttle-boxes, the 
 weight being made in sections, that it may be regulated to suit the number of shuttles employed. As 
 the shuttle-boxes are connected with the arbor F, it will be obvious that then - weight will carry them 
 down, when permitted so to do by the turning of the arbor in one direction, and that they will be lifted 
 when the arbor is turned in the reverse direction. On the inner end of the said arbor there is a cog- 
 wheel e“, the cogs of which engage a pinion/ 6 of one-sixth its diameter, which has attached to its face a 
 wheel (/ with a portion of its periphery cut off, against which bears a stop IP on the end of a rod sur- 
 rounded by a helical spring P, which forces the stop against the periphery of the wheel cut out, so that 
 when the wheel is turned, the pressure of the stop shall have the effect to stop the wheel, to aid in 
 bringing the parts to a state of rest in the proper position, and there hold them. The wheel e 6 has six 
 Vol. II. — 20 
 
BOG 
 
 LOOM, CARPET- WEAVING. 
 
 pins projecting from its inner face, at equal distances apart, and so proportioned that the turning of the 
 wheel the distance of one of these pins shall shift the shuttle-boxes to a distance required for one 
 change. There are two rods/ 5 / 1 , one on each side of the axis of the wheel c-°, and so far apart that 
 when thrown out they will not touch the pins on the -wheel. These rods are jointed to a sliding-frame 
 k e above, adapted to work on a guide-rod, and suspended to a lever p 3 that carries a roller /t 3 working 
 in a cam-groove i 3 on the shaft f, which makes two revolutions to each beat of the lathe, so that the 
 lever and rods f will be carried up and down every alternate beat of the lathe ; and there being a 
 similar arrangement on each side of the loom, with the cams placed on opposite sides of the axis, one 
 set will be w r orked for each beat of the lathe. The rods ff before described, are drawn together by 
 a helical spring l 6 to bring their inner edges against the pins of the wheel e 6 . Their inner edges are 
 formed each with a hook m°, so that when drawn up the hooks catch under the pins to turn the wheel ; 
 and as the two rods are on opposite sides of the axis of the wheel, the wheel can be turned in either 
 direction if the appropriate hook be brought in the required position. The manner in which the rods 
 are drawn inwards has been pointed out. They are kept out so that their hooks shall not engage the 
 pins as they are moved up and down at each operation, by means of weights n e n? (represented by 
 dotted lines) suspended to cards o 6 o 6 attached to levers rf rf, which by the force of the weights are 
 made to bear against the inner faces of the said rods f, and to overcome the tension of the spring 
 which tends to draw them in. The weights n 6 n 0 are connected each to one of the cards (not repre- 
 sented) of the jacquard, so that when either weight is lifted by the jacquard, the corresponding rod f 
 will be drawn inwards by its spring, and hence, when drawn up by the rotation of the cam, as before 
 described, its hook will catch under one of the pins and turn the wheel, and hence shift the shuttle- 
 boxes. As these movements are very quick, and it is important that the shifting motion be accurate, 
 the two rods are bent in at their lower ends to such an extent, that when drawn up, with the hook of 
 one turning the wheel at the required extent of motion, the said bent projection of the other comes in 
 contact with another one of the pins on the wheel, and thus effectually stops the movements. In this 
 way it will be seen that by the punching of the cards that operate the needles connected with the 
 cards that control the weights to disengage the hooks, the shuttles can be shifted to suit any variety of 
 changes of color in the pattern. 
 
 The connection between the frames that carry the hook-rods ff and the levers operated by the 
 cams to give the shuttle-motions, is by means of spring-gripes, which hold by friction surface, so that 
 in case of an imperfect throw of a shuttle, or any other impediment, the connections will yield instead 
 of breaking. This is effected in the rear or receiving shuttle-boxes by the weighted lever, which is suffi- 
 cient to move the boxes, but not to strain the parts in case of any impediment. 
 
 When a shuttle enters either of the boxes, it is arreted in part by its point striking against the 
 picker, which soon becomes so indented as to permit the point of the shuttle to lodge therein, and 
 therefore it will be seen that in this condition of the parts the shuttle-boxes could not be shifted, or 
 rather would be seriously impeded, for the shuttle being in the box which is to rise, and its point im- 
 bedded in the picker, which does not move up, the parts would thus be held or strained. To prevent 
 this, at the time the shuttle enters a box the picker is forced inwards by a lever r 6 , which is afterwards 
 drawn back to permit the picker to be drawn back clear of the point of the shuttle by the spring of 
 the picker-staff. There are four such levers r 4 , one for each series of shuttle-boxes ; they turn on ful- 
 crum-pins on the pendulous frames, and at their lower ends carry wrist-pins that work in cam-grooves 
 on wheels s that turn on stud-pins on the lower ends of the pendulous frames, and from each of these 
 wheels extends an arm f with a slot near the end, playing on a pin v? attached to the floor, so that as 
 the pendulous frame vibrates, the required vibratory motion shall be given to the cam-groove wheels 
 One such cam-groove wheel answers for two levers, as shown in the plates. 
 
 The warps pass from the warp-beam below the floor, and pass over a roller e 1 above the warp-beam, 
 and thence through the mails of the trap-cards in the usual manner of mounting a jacquard loom. The 
 woven cloth from the breast-beam passes between two rollers f f, one of which is weighted to 
 make pressure against the other, that the cloth may be gripped between the two with sufficient force to 
 prevent it from slipping. And thence the cloth is wourfa' upon the cloth-beam, (not represented,) which 
 is driven by a friction-strap with sufficient velocity to take up the slack, the band slipping on the pul- 
 ley when the diameter of the beam becomes so large as to tend to wind on the cloth faster than it is 
 carried forward by the two rollers ff, which constitute what is called a positive take-up motion, and 
 which receive the same motion for each beat of the lathe, that the same length - of cloth may be taken 
 up for each operation of the loom, and thus measure the figure to be produced on the cloth. As the 
 mechanism for giving this regular and positive take-up motion to the rollers was not invented by Mr. 
 Bigelow, but was previously well known to weavers, it is deemed unnecessary to give a description of 
 it here. 
 
 The mode of operating the yarn-beam is not represented, but it will be understood with sufficient 
 clearness from the description alone. 
 
 On the shaft of the yarn-beam there is a cog-wheel operated by a worm on a vertical shaft, which 
 carries a crown ratchet-wheel, the teeth of which are engaged by a pall, or ratchet-hand, on the end of 
 a rod jointed to -the sword of the lathe, so that as the lathe beats back, by the connections described, 
 the ratchet-wheel is turned a given portion of a revolution, which shall be sufficient to give out the re- 
 quired quantity of warp-threads for any one operation of the loom. But as the diameter of the beam 
 is constantly varying, beginning with a large diameter, and gradually diminishing as the warps are 
 given out, and the demand for warps is constantly varying, by reason of the irregularities of the weft- 
 threads and the ingraining of the fabric, the regular and positive motion of the warp-beam given by 
 the mechanism requires to be varied to suit the varying conditions above described. This, as before 
 intimated, is governed by the tension of the warps between the beam and the woven cloth. The roller 
 ?’ over which the warps pass from the warp-beam is hung in the upper ends of two levers f f' which 
 have their fulcra at W\ and the lower arms of these levers are formed in sector-racks i', the cogs oi 
 
LOOM, CARPET-WEAVING. 
 
 307 
 
 which engage pinions f on the ends of a shaft, and this shaft is provided with an arm which carries a 
 weight P, which, by the connections of the pinions and sector-racks, tends always to force back the 
 roller e 1 to keep the warps under the same, or nearly the same tension. This weight is adjustable on the 
 arm by a set-screw, to regulate the degree of tension, to suit the quality of the warps and the fabric to 
 be produced. From this it will be seen not only that the warps will be always kept under the same 
 degree of tension during the operation of weaving, a condition very essential to the production of a 
 fabric of regular texture, but if the quantity of warps given out by the warp-beam be greater than the 
 quantity taken up in weaving, the roller will be carried back by the weight, and that when the quantity 
 is less than enough, the roller will be drawn forward. This motion of the roller is made use of to reg- 
 ulate the motion of the warp-beam in the following manner : On the shaft before described there is 
 another arm, to which is jointed one end of a connecting-rod, the other end of which is in turn jointed 
 to an arm which turns on the arbor just above the ratchet-wheel, and this arrli carries a plate that rests 
 on the face of the ratchet-wheel, so that when the roller is carried back by the action of the weight 
 when the supply of warps is too great, the shaft is turned in one direction, which, by the connection de- 
 scribed, carries the plate so far over the surface of the ratchet-wheel as to cover all, or only a portion 
 of the teetli which would otherwise have been engaged by the band, and hence the let-off motion of 
 the warp-beam is either entirely or partly prevented ; and when, on the other hand, the roller is drawn 
 forward by the amount of warps given being insufficient, the plate is drawn back, which permits the 
 band to engage the teeth of the ratchet, and to operate the warp-beam, to give out the required quan- 
 tity of warps. In this way the supply of warps is proportioned to the demand, and the cloth being 
 taken up by a positive and measured quantity at each operation, it follows that the irregularities will 
 be thrown into the thickness instead of the length of the cloth, and hence the figures will be produced 
 of a regular and measured length, whatever may be the irregularities of the weft-threads and the in- 
 graining. 
 
 But there is still another condition which is important to be observed. The roller e 7 must be suffi- 
 ciently sensitive to yield to the tension of the warps undgr the force of the weight suspended to the 
 arm of the shaft connected with the levers that carry the roller ; and hence, when the lathe beats up the 
 weft-threads, it would yield to the force of the beat, particularly in weaving fabrics of a close texture, 
 which motion would have the effect to prevent the full action of the reed, and cause the cloth of loose 
 texture to lay up in front of the reed, and in a short time impede the proper working of the loom. To 
 
 E revent this, the shaft carries a wheel m 1 , and around a portion of its circumference passes a friction- 
 rake, rp ; that is, a metal strap jointed to the frame and to a connecting-rod o’, attached to the sward 
 of the lathe, so that when the lathe beats up, this metal strap is drawn in contact with the periphery 
 of the wheel, and thus by friction holds it firmly so that it cannot turn, by the connections holding the 
 roller firmly, that the warps may be prevented from yielding to the force of the beat of the lathe. In 
 this way the desired effect is produced ; Viz.., that of producing a close fabric of regular texture and 
 measured figure, with the irregularities thrown into the thickness instead of the length of the cloth. 
 
 So soon as the shuttle has been thrown the weft-thread lies between the warps in a diagonal line 
 from the selvage on one side to the shuttle-box on the other, and this diagonal line being longer than 
 the breadth of the cloth, it is evident that if the weft-thread were beaten up freely, it would become 
 loose and produce a bad selvage. To prevent this, the sides of the frame at a? constitute a bed on each 
 side, grooved to receive a series of fingers IP, jointed to the frame, and the moment the shuttle has 
 passed a cam cP, on the lathe-shaft, permits the fingers to fall on to, and gripe the weft-thread, so that 
 when it is carried forward by the reed it is resisted by the pressure of the fingers, which gives the 
 required pull to insure a good selvage. The cam then passes around to lift the fingers, that the shuttle 
 may pass. These fingers are made to answer the purpose also of stopping the loom when the weft- 
 thread has not been carried across ; for then, as the fingers descend, not being held up by the weft- 
 thread, they enter the grooves, and the arm at the back acts as catch-levers connected with the shipper 
 to stop the loom. 
 
 The manner of operating the lathe has beem described with sufficient clearness in pointing out the 
 characteristics of this invention, and it is thereiwe unnecessary to give a more detailed description of it. 
 
 The belt is shifted from the loose to the fast pulley, and vice versa, by the belt shipper a 4 , and belt- 
 guide b'\ in the usual way; but to adapt this to the introduction of a reversing motion, the shipper and 
 the guide are differently arranged. The shipper a 4 , and the belt-guide & 4 , are on opposite ends of a 
 shaft c 9 , hung in appropriate boxes, and this shaft is hollow, and within it there is an arbor cl 1 , which 
 extends out at each end. From the rear end of this inner arbor projects an arm e 4 , which carries a 
 wrist-pin/ 4 , that fits and slides freely but accurately in a curved mortise y 4 , in one arm of a lever IP, 
 that turns on a fulcrum-pin i 4 , its other arm being jointed to the connecting-rod of the brake/, that 
 works against the inner periphery of the fast pulley b, in the usual way of arranging the brake for 
 arresting the operation of the loom when the belt is shifted from the fast to the loose pulley. When 
 the inner arbor d* is therefore connected with the shaft of the shipper, the brake is operated to make 
 friction on the fast pulley when the belt is shifted to the loose pulley, and liberated to relieve the fric- 
 tion when the belt is shifted to the fast pulley, the motion of the shipper to shift the belt from the one 
 to the other of the pulleys being sufficient to move the arm c i , so that its wrist / 4 shall move over a 
 distance equal to half the length of the curved mortise in the lever of the brakes, the curve and the 
 length of this mortise being such that moving the wrist-pin from either end of the mortise to the middle 
 will force the brake against the pulley to make friction, and moving it from the middle towards either 
 end will remove the brake. As I employ the loose pulley for the purpose of giving the reverse motion, 
 it becomes necessary in the first place to stop the loom, and then to start it in the reverse direction, 
 and therefore in shifting the belt from the fast to the loose pulley, the brake at first must be operated 
 to make friction to arrest the parts, and then liberated whilst the mechanism of the reversed motion is 
 brought into action. This is effected in the following manner : on the front end of the arbor d', when 
 it projects beyond the hollow shipper-shaft, there is an arm g*, which projects out towards the middle 
 
308 
 
 MACHINES. 
 
 of the loom, nearly in a horizontal direction and at a convenient height to be reached by the attendant's 
 foot. On this arm is journalled a treadle A 4 , and so connected with the arm g*, by means of a helical 
 spring i 4 , that when no force is applied to it, an armj 4 , which projects upward from its inner end, is 
 held against a projection k 4 of the shipper, so that the arbor of the brake and the shaft of the shipper 
 are kept in a locked condition by the helical spring i* to be operated together ; but when pressure is 
 applied on the top of the treadle, then the brake is operated separately to remove the friction from the 
 pulley. When the attendant moves the shipper towards him, the belt is shifted from the fast to the 
 loose pulley, the brake at the same time being drawn down to make friction for arresting the momentum 
 of the moving parts, and then the attendant with his foot forces down the treadle which relieves the 
 brake, thereby liberating the parts preparatory to the reversing motion which is brought into action by 
 the same motion. From the bottom of the treadle projects an arm l 4 , that carries a pin m 4 , that plays 
 freely in a mortise w 4 , in t"he end of a sliding-rod o 4 , and the length of this mortise is such that the mo- 
 tions given to the arm Z 4 by the ordinary motions of the shipper will not communicate motion to the 
 sliding-rod, but when the treadle is borne down to relieve the brake after the shifting of the belt into 
 the loose pulley, the sliding-rod is drawn in the direction of the arrow. 
 
 The sliding-rod o 4 is jointed to the lower arm of a lever y> 4 , which turns on a fulcrum-pin q\ its uppei 
 arm being forked and made to embrace the collar r 4 of a wheel s 4 , which slides freely on the main driv- 
 ing-shaft a of the loom. When the sliding-rod o 4 is drawn in the direction of the arrow, it forces the 
 wheel s 4 against the face of a friction-plate u'\ which is fast on the main shaft, and this friction-plate 
 has the effect of locking it with the main shaft, so that any motion given to this wheel s 4 will drive the 
 main shaft. The hub v ' of the loose pulley carries a pinion w*, which engages another pinion x i , on a 
 parallel shaft y 4 , the other end of which has a pinion z 4 , which engages cogs on the inner periphery of 
 the wheel s 4 , so that the motion of the loose pulley communicates a reversed motion to this wheel, which 
 drives the main shaft in the reversed direction whenever they are locked together by the friction-plate. 
 
 The moment the attendant removes his foot from the treadle, the wheel is withdrawn from the fric- 
 tion-plate by the tension of a helical spring a», on the slide-rod o 4 , and the parts are then in a condition 
 for starting the loom by the shifting of the belt on to the fast pulley.* 
 
 MACHINES are instruments employed to regulate motion, so as to save either time or force. 
 
 The maximum effect of machines is the greatest effect which can be produced by them. In all urn 
 chines that work with a uniform motion there is a certain velocity, and a certain load of resistance, that 
 yields the greatest effect, and which are therefore more advantageous than any other. A machine may 
 be so heavily charged that the motion resulting from the application of any given power will be but just 
 sufficient to overcome it, and if any motion ensue it will be very trifling, and therefore the whole effect 
 very small. And if the machine is very lightly loaded, it may give great velocity to the load ; but 
 from the smallness of its quantity the effect may still be very inconsiderable, consequently between 
 these two loads there must be some intermediate one that will render the effect the greatest possible. 
 This is equally true in the application of animal strength as in machines.! 
 
 1. The maximum effect of a machine is produced when the weight or resistance to be overcome is 
 four-ninths of that which the power, when fully exerted, is able to balance, or of that resistance which 
 is necessary to reduce the machine to rest ; and the velocity of the part of the machine to which the 
 power is applied should be one-third of the greatest velocity of the power. 
 
 2. The moving power and the resistance being both given, if the machine be so constructed that the 
 velocity of the point to which the power is applied be to the velocity of the point to which the resist- 
 ance is applied, as four times the resistance to nine times the power, the machine will work to the 
 greatest possible advantage. 
 
 3. This is equally true when applied to the strength of animals ; that is, a man, horse, or other animal 
 
 will do the greatest quantity of work, by continued labor, when his strength is opposed to a resistance 
 equal to four-ninths of his natural strength, and his verity equal to one-third of his greatest velocity 
 when not impeded. * 
 
 Now, according to the best observations, the force of a man at rest is, on an average, about 70 lbs.; 
 and his greatest velocity, when not impeded, is about 6 feet per second, taken at a medium. Hence 
 the greatest effect will be produced when the resistance is equal to about 31 l-9th pounds, and his uni- 
 form motion 2 feet per second. * 
 
 The strength of a horse at a dead pull is generally estimated at about 420 pounds, and his greatest 
 
 • The history of the invention of this machine is so full of instruction to the young mechanic, and the facts of the case 
 coming entirely within our own knowledge, we have been induced to dwell upon them, although by so doing we have de- 
 parted somewhat from the original plan of the Dictionary, which would confine all description to the machines themselves. 
 
 t These conditions are deduced from the following empirical expression, which is adopted by Euler and other waiters, 
 to represent the law of the moving power: Let 1’ = the power applied, (or weight which the power, when fully exerted, is 
 just able to overcome ;) B = the resistance, or load, or weight to be overcome ; c the greatest velocity, or that at which 
 the power ceases to act; a = any other velocity: then the law of the moving power is 
 
 ’The variables in this expression are R and v, and the effect is represented by the product E v ; on making which a max- 
 imum, the rules of the differential calculus give v = i c ; whence the formula becomes E = |P. 
 
 From these expressions it follows, that when the moving power and the resistance are both given, if a machine be so 
 constructed that the velocity of the part to which the power is applied is to the velocity of the part to which the resistance 
 is applied in the ratio of 9 R to 4 P, the effect of the machine will be a maximum, or it will work to the greatest possible 
 advantage. The above conditions apply equally to machines impelled by animal force and the agents of nature, as running 
 water, steam, the force of gravity, &c. An animal exerts itself to the greatest advantage, or performs the greatest quantity 
 of work in the least time, when it moves with about one-third of the utmost speed with which it is capable of moving. 
 4iid is loaded with four-ninths of the greatest load which it is capable of putting in motion. 
 
MACHINES. 
 
 309 
 
 rate of walking 10 feet per second; therefore the greatest effect is produced when the load = 18G| 
 pounds, and the velocity y, or 3J feet per second. 
 
 4. A machine driven by the impulse of a stream produces the greatest effect when the wheel move® 
 with one-third of the velocity of the water. 
 
 The following may be taken as a general arrangement of machines : 
 
 Class I. — Machines for overcoming inertia. 
 
 Machines for raising weights. 
 
 Machines for transporting weights on land. 
 Machines for raising water. 
 
 Blowing machines. 
 
 Machinery for ascending and descending in fluida 
 Machines for navigation, &c. 
 
 Ploughs. 
 
 Drilling machines. 
 Reaping machines. 
 Threshing machines. 
 Mills. 
 
 Boring machines. 
 
 Class II. — Machines for overcoming cohesion. 
 
 Cutting machines. 
 
 Machines for cleaning, or removing impurities. 
 Grinding machines. 
 
 Machines for turning. 
 
 Machines which act by compression. 
 
 Pile engines, &c. 
 
 Class III. — Machines for combining materials. 
 
 Machines for weaving cloths, carpets, nets, stockings. | Machine for combining materials in brewing, die. 
 
 Class IY. — Machines for measuring forces. 
 
 Anemometers. 
 
 Torsion machines. 
 Balances and steelyards. 
 Barometers. 
 Thermometers. 
 Hygrometers. 
 
 Machines for measuring the elasticity and strength 
 of materials. 
 
 Dynamometers for measuring the force of men, 
 animals, and other agents. 
 
 Machines for measuring the force of projectiles. 
 Machines for measuring the force of running water. 
 
 Class V. — Machines for measuring and dividing space. 
 
 Quadrants. 
 
 Circles. 
 
 Theodolites. 
 
 Levels. 
 
 Micrometers. 
 
 Goniometers. 
 
 Dividing machines. 
 
 Odometers. 
 
 Drawing and copying instruments. 
 
 Class VI. — Machines for measuring time. 
 
 Machinery . — The utility of machinery, in its application to manufactures, consists in the addition 
 sdiich it makes to human power, the economy of human time, and in the conversion of substances ap- 
 parently worthless into valuable products. The forces derived from wind, from water, and from steam, 
 are so many additions to human power. The difference between a tool and a machine is not capable 
 of very precise distinction, nor is it necessary, in a popular examination of them, to make any distinction. 
 A tool is usually a more simple machine, and generally used by the hand ; a machine is a complex tool, 
 a collection of tools, and frequently put in action by inanimate force. All machines are intended to 
 transmit power. Of the class of mechanical agents by which motion is transmitted — the lever, the 
 pulley, the wedge — it has been demonstrated that no power is gained by their use, however combined. 
 Whatever force is applied at one part can only be exerted at some other, diminished by friction and 
 other incidental causes ; and whatever is gained in the rapidity of execution, is compensated by the 
 necessity of exerting additional force. These two principles should be constantly borne in mind, and 
 teach us to limit our attempts to things which are possible. 
 
 1. Accumulating power . — When the work to be done requires more force for its execution than can 
 be generated in the time necessary for its completion, recourse must be had to some mechanical method 
 of preserving and condensing a part of the power exerted previously to the commencement of the pro- 
 cess. This is most frequently accomplished by a fly-wheel, which is a wheel having a heavy rim, so 
 that the greater part of the weight is near the circumference. It requires great power, applied for some 
 time, to set this in rapid motion ; and when moving with considerable velocity, if its force is concen- 
 trated on a point, its effects are exceedingly powerful. 
 
 2. Regulating powers — Uniformity and steadiness in the motion of the machinery are essential both to 
 its success and its duration. The governor, in the steam-engine, is a contrivance for this purpose. A 
 vane or fly, of little weight, but large surface, is also used. It revolves rapidly, and soon acquires a 
 uniform rate, which it cannot much exceed ; because any addition to its velocity produces a greater ad- 
 dition to the resistance of the air. This kind of fly is generally used in small pieces of mechanism, and, 
 unlike the heavy fly, it serves to destroy instead of to preserve force. 
 
 3. Increase of velocity . — Operations requiring a trifling exertion of force may become fatiguing by the 
 rapidity of motion necessary, or a degree of rapidity may be desirable beyond the power of muscular 
 action. Whenever the work itself is light, it becomes necessary to increase the velocity in order to 
 economize time. Thus, twisting the fibres of wool by the fingers wmuld be a most tedious operation. 
 In the common spinning-wheel, the velocity of the foot is moderate, but, by a simple contrivance, that 
 of the thread is most rapid. 
 
 4. Diminution of velocity . — This is commonly required for the purpose of overcoming great resistances 
 with small power. Systems of pulleys afford an example of this. 
 
310 
 
 MAGNET— MAGNETISM. 
 
 5. Spreading the action of a force exerted fcr a fe,v> minutes over a large time. — This is one of the most 
 common and useful employments of machinery. The half-minute which we spend daily in winding up 
 our watches is an exertion of force which, by the aid of a few wheels, is spread over 24 hours. 
 
 6. Saving time in natural operations. — The process of tanning consists in combining the tanning prin- 
 ciple with every particle of the skin, which, by the ordinary process of soaking it in a solution of the 
 tanning matter, requires from six months to two years. By inclosing the solution, with the hide, in a 
 close vessel, and exhausting the air, the pores of the hide being deprived of air, exert a capillary at- 
 traction on the tan, which may be aided by pressure, so that the thickest hides may be tanned in six 
 weeks. The operation of bleaching affords another example. 
 
 7. Exerting forces too large for human power. — When the force of large bodies of men or animals is 
 applied, it becomes difficult to concentrate it simultaneously at a given point. The power of steam, air, 
 or water, is employed to overcome resistances which would require a great expense to surmount by 
 animal labor. The twisting of the largest cables, the rolling, hammering, and cutting of large masses 
 of iron, the draining of mines, require enormous exertions of physical force, continued for considerable 
 periods. 
 
 8. Executing operations too delicate for human touch. — The same power which twists the stoutest 
 cable and weaves the coarsest canvas may be employed, to more advantage than human hands, in 
 spinning the gossamer thread of the cotton, and entwining the meshes of the most delicate fabric. 
 
 9. Registering operations. — Machinery affords a sure means of remedying the inattention of human 
 agents, by instruments, for instance, for counting the strokes of an engine, or the number of coins struck 
 in a press. 
 
 10. Economy of materials. — The precision with which all operations are executed by machinery, and 
 the exact similarity of the articles made, produce a degree of economy in the consumption of the raw 
 material which is sometimes of great importance. 
 
 11. The identity of the result. — Nothing is more remarkable than the perfect similarity of things man- 
 ufactured by the same tool. This result appears in all the arts of printing : the impressions from the 
 same block, or the same copper-plate, have a similarity which no labor of the hand could produce. 
 
 12. Accuracy of the work. — The accuracy with which machinery executes its work is, perhaps, one ol 
 its most important advantages. It would hardly be possible for a very skilful workman, with files and 
 polishing substances, to form a perfect cylinder out of a piece of steel. This process, by the aid of the 
 lathe and the sliding-rest, is the every-day employment of hundreds of workmen. 
 
 Machines are classed under different denominations, according to the agents by which they are put in 
 motion, the purposes they are intended to effect, or the art in which they are employed. 
 
 The reader is referred to the various machines, under their respective heads. 
 
 MAGNET — MAGNETISM. The magnesian stone, or native magnet, abounds in various parts of 
 tne earth, especially in iron mines, where it is found massive, frequently crystallized, and occasionally 
 m beds of considerable thickness. Its constituents are, for the most part, oxygen and iron under the 
 form of two oxides, the black and red. In 100 parts, we have about 73 parts iron and 27 oxygen : it 
 has been termed magnetic iron ore. Its color varies from a reddish black to a deep gray. Native 
 magnets from Arabia, China, and Bengal are commonly of a reddish color, and are powerfully attractive 
 Those found in Germany and England have the color of unwrouglrt iron. 
 
 The specific gravity of magnetic iron ore is about 4-J- times that of water, and affords, when worked, 
 excellent bar-iron. 
 
 This remarkable substance has not only the power of drawing apparently towards itself small parti- 
 cles of iron, but it has also the important property of communicating or propagating, as it were, its own 
 attractive power through a series of masses, so as to cause them to hang one on another in a sort of 
 linked chain. 
 
 If the magnet be suspended by a delicate silk line from some point between the surfaces of attraction, 
 so as to admit of its turning freely on that point, the mass will rest only in one position : this position 
 will be such as to place its poles either in the line of the meridian, or very near it ; one of the surfaces 
 of the mass will have turned towards the north, and the opposite surface towards the south, and, if 
 drawn aside from this position, will continue to vibrate backwards and forwards until it again rests in 
 the same position. 
 
 The attractive force of the loadstone or natural magnet cannot generally be considered as of any 
 great amount. Native magnets in their rude state will seldom lift their own weight, and, with some 
 rare exceptions, their power is limited to a few pounds. 
 
 The effective power of the loadstone may be considerably improved by means of what is termed an 
 armature , which consists of small pieces of very soft iron applied to the opposite polar surfaces of the 
 stone, and projecting a little below it on each side. The attractive force is thus transmitted to the 
 small projecting or artificial poles of iron ; this is found not only to augment the power, but also to en- 
 able the experimentalist to bring both the poles to bear upon any given mass at the same instant. 
 
 The pieces intended for the armature should be made of very soft iron, and each formed with a ver- 
 tical face about gth to ^th of an inch thick, with a projecting solid foot below, as at ap and l n, Fig. 
 2672 ; the vertical face being closely applied to the polar surfaces, and the mass allowed to rest on the 
 projecting feetpw, forming the artificial poles. Things being thus arranged, the whole is bound firmly 
 together by a cap of silver or brass, or by plain metallic bands, as represented in A B and C D, Fig. 2673. 
 A ling R is usually fixed in the upper part of the cap for the convenience of raising the whole mass, 
 and a transverse piece of soft iron K, termed a keeper or lifter, furnished with a central hook G, is 
 placed across the artificial poles p n, so as to unite them. This keeper is found to preserve and increase 
 the attractive force of the poles, especially if the magnet be suspended by its upper ling R, and weights 
 be attached to the book G, and by which its power may be roughly estimated. 
 
 If the armed magnet be thus suspended, and a small scale-pan attached to the keeper II, an additional 
 
MAGNET— MAGNETISM. 
 
 311 
 
 weight may be added daily for a considerable time : the loadstone thus armed may be caused to sustain 
 from twenty to thirty times its own weight. 
 
 When an armed loadstone is employed for particular experimental inquiries or other purposes, the 
 keeper K may be removed, but it should be replaced when the magnet is not in use. 
 
 If we suspend a magnet by a fine silk fibre over another magnet, or near another magnet also sus- 
 pended, the poles of these magnets will arrange themselves in such a way as to bring the opposite 
 poles together ; the similar poles are found so powerfully and reciprocally repulsive, as not to allow 
 ‘he masses to rest with their similar poles in juxtaposition. 
 
 2C73. 
 
 Pieces of common iron, which have been for a great length of time in one fixed position, or under- 
 ground, acquire considerable polarity — in fact, become magnets. In the “ Memoirs of the Academy oi 
 Sciences” for 1731, we find an account of a large bell at Marseilles having an axis of iron: this axis 
 rested on stone blocks, and threw off from time to time great quantities of rust, which, mixing with the 
 particles of stone and the oil used to facilitate the motion, became conglomerated into a hardened mass : 
 this mass had all the properties of the native magnet. The bell is supposed to have been in the same 
 position for 400 years. 
 
 The artificial magnet. — To make an artificial magnet, procure a small bar of steel about 8 inches in 
 length, Ith of an inch wide, and Jth of an inch thick, or a piece of common steel wire of about the same 
 length, and from |th to ^th of an inch in diameter. Let the steel be well hardened and tempered by 
 plunging it at a cherry-red heat into cold water ; when cold and polished, apply each extremity in sue 
 cession to the opposite poles of an armed magnet, Fig. 2672, first touching with gentle friction one ex 
 tremity of the bar, or one of the poles and the opposite extremity on the other pole, or, which is bettejj 
 draw the bar a b, Fig. 2674, a few times, in the direction of its length, across the two poles mn of the 
 magnet M, as represented in the figure, and in such a way as not to pass either extremity, a h, beyond 
 or off the opposite poles mn; finally, bring the bar a b so as to rest with its extremity a 'b equally dis- 
 tant from each pole m n ; that is to say, bring the poles m n at the centre of the bar, or as nearly as 
 may be. In this position remove the bar from the poles. The bar will now be found attractive of 
 particles of iron, common steel needles, and other ferruginous matter : when suspended it will arrange 
 itself in the direction of the magnetic meridian, and will, in fact, have all the properties of the loadstone, 
 including the important property of imparting or exciting a magnetic condition in tempered steel. 
 
 Take a small bar of steel which has been rendered magnetic by the process just described, apply it 
 with slight friction to a piece of hard steel wire or a similar bar, and in such way that the opposite 
 extremities of each bar may have contact attended by a slight degree of friction : this second bar or 
 wire will be found also to have acquired a similar magnetic condition to the first ; and this process may 
 be continued from the second to a third wire of steel, and so on without limit. 
 
 The propagation of magnetism from one bar of steel to another, as illustrated in this experiment, en- 
 ables the experimentalist to obtain artificial magnets to any given amount ; and since the form and 
 magnitude of the steel has not been found to interfere with the generality of the result, we are further 
 enabled to obtain magnets of any required figure or magnitude. 
 
 It is to be especially observed that the polarities excited in the opposite portions of a steel bar by 
 this artificial process of magnetizing are the reverse of those of the magnetic poles to which these por- 
 tions have been applied. Thus in Fig. 2674, if the extremity b of the steel a b rest on the north, or 
 positive pole n of the magnet M, the polarity induced in that extremity b will be a south or negative 
 polarity. Reciprocally, if the extremity n be brought to rest on the negative or south pole m, then the 
 polarity induced in that point of the steel will be a positive or north polarity. 
 
 Artificial magnets may be of any required form, or of almost any dimensions, according to the par- 
 ticular views of the experimentalist : for general purposes they are limited to straight bars, such as 
 represented in Fig. 2675, or otherwise to bars bent into a curvilinear form, resembling a horse-shoe, as 
 m Fig. 2676 ; the branches cp and c n bemg longer, and the extremities p n nearer than in the common 
 horse-shoe. Many such bars, either straight or curved, form, when combined, what is termed a com- 
 vound magnet, such, for example, as that represented in Figs. 2677 and 2678. The combination of 
 several compound magnets with projecting armatures constitutes a magnetic battery or machine. The 
 dimensions well adapted to magnetic bars, either straight or curved, are such as to give the breadth 
 about -A th or -Ath of the leng th, and the thickness something less, or not exceeding one-half of the 
 breadth. ° 
 
•512 
 
 MA GNEP— MAGNETISM. 
 
 To magnetize a bar of tempered steel, Fig. 2676, curved into the horse-shoe form, fix the bar, Fig 
 2679, on a flat board, with its extremities, p s, against a straight piece of soft iron, p s, of the same 
 thickness and width as the bar. Having secured the whole in this position, place a compound magnet 
 M, or an armed native magnet, on one of the extremities s, of the curved bar, taking care that the oppo- 
 site or marked and unmarked ends are in contact with each other. Continue as before to glide the 
 magnet M several times round the whole series, and in the same direction, s cp, finally stopping in the 
 
 2675. 
 
 2677. 
 
 2678. 
 
 centre, c. Repeat this process on each face of the bar, when a high degree of power will have become 
 developed ; so much so, that the iron or keeper p s cannot be directly pulled away without considerable 
 force, and in some instances cannot be conveniently removed except by sliding it off. 
 
 In order to preserve effectually the magnetism thus excited in bars of steel, it is requisite, when not 
 in use, to keep their opposite poles united by means of pieces of soft iron. 
 
 2080. 
 
 2670. 
 
 Take a perfectly straight and even bar of steel, P S, Fig. 2680, sufficiently hard to retain.a magnetic 
 state. It may be 7 inches long, Jth of an inch wide, and -Ath of an inch thick. Drill a clean hole 
 through the centre of the wide surface, and then pass an extremely fine drill also through the centre 
 transversely to this hole, across the thickness of the bar, edgewise, and so accurately as to pass through 
 the centre of gravity of the mass, or as nearly as possible ; proceed now to complete the equilibrium of 
 the bar upon a fine needle as an axis, and in such a way as to render it indifferent as to position in a 
 vertical plane or nearly so, and that whether it be placed with one or the other face uppermost. Let 
 the bar be now magnetized, and then mounted on its central axis ; run the axis through a small silver 
 stirrup c r, and suspend the whole by a fine silk fibre r t, attached to a fixed point t ; the bar P S will 
 be observed gradually to assume a definite and oblique position, p n, inclining in these latitudes its 
 north pole, P, nearly 70 degrees below the horizontal line, turning at the same time into a plane devia- 
 ting from the plane of the meridian by a given angular quantity, called “ the dip,” the lower extremity 
 having turned towards the north, and the other extremity towards the south ; and it may be likewise 
 observed, on the principle already stated, that the extremities which have thus turned, the one towards 
 the north and the other towards the south, will have been derived from the opposite poles of the load- 
 stone or magnet by which it has been magnetized. 
 
 The position of the magnetic centre and poles of each surface, together with the general magnetic 
 condition of the bar, and the reciprocal attractions, repulsions, and neutralization of the opposite forces, 
 may be shown in the following way. 
 
 Strain a piece of common drawing-paper on an open frame, AC, Fig. 2681, and place it over a hard 
 steel bar S N, regularly and powerfully magnetic ; project on the paper over the bar, through a small 
 muslin or lawn sieve, some fine iron dust or filings ; the particles will arrange themselves in a series of 
 
MAGNET— MAGNETISM. 
 
 312 
 
 curved lines of magnetic force proceeding from homologous or similar points on each side of the middle 
 of the bar, some uniting about the magnetic centre, others standing out at the extremities as if repelled 
 from the poles FT S, and tending to turn at considerable distances into other curved lines of force, to 
 unite their branches between the opposite poles. This experiment may be rendered more decisive by 
 slightly tapping the finger on the paper, so as to give the particles a little vibration. 
 
 Oppose the dissimilar poles S N, Fig. 2681|, of two powerful bars to each other at about two inches 
 
 2681 . 2681 *. 
 
 distance, and project over them fine iron filings as before ; similar results ensue. Magnetic lines of 
 force, both straight and curved, and proceeding from similar points of each bar, will be apparent, uniting 
 the two poles by chains of reciprocal attraction. 
 
 Change the position of one of the bars, so as to oppose two similar poles N iST, Fig. 2682 ; the lines of 
 force will then appear to be conflicting lines ; the repulsive forces will cause a straight line a 5 to appear 
 on the open space or field between the poles, from which the iron dust stands out transversely. At 
 this line, the opposed forces on either side are apparently struggling with each other, being exerted in 
 repulsive directions from the opposed poles. 
 
 • 2682 . 2683 . 
 
 We have in these phenomena satisfactory visual evidence of the existence of two distinct forces — of 
 their reciprocal attractions and repulsions, and their mutual neutralization. 
 
 A light magnetic bar N S, Fig. 2683, or a small magnetic steel cylinder, of great comparative length, 
 has been termed a magnetic needle. When delicately poised on a central point c, so as to retain a hori- 
 zontal position, and move freely in a horizontal plane, it has been termed the horizontal needle. When 
 poised on a fine central axis, so as to move freely in a vertical plane, it has been termed a vertical or 
 dipping needle. If suspended as in Fig. 2683, so as to have motion in both a horizontal and vertical 
 plane, it has been termed the horizontal and vertical needle. 
 
 Instruments for ascertaining whether a substance has polarity or not, and for detecting the presence 
 and kind of force in operation, have been termed magnetoscopes. The most simple kind of magneto- 
 scope is a small horizontal needle, about an inch in length, delicately suspended by a fine silk fibre, or 
 otherwise set upon a fine point and agate centre, within a small wood or glass 
 case, as represented in Fig. 2681, and so set as to admit of some degree of dip or 2681. 
 
 depression of either pole, as well as a perfect motion in a horizontal plane. From 
 the attractive and repulsive forces of similar and dissimilar poles it is evident, 
 from the kind of effect produced on the poles of the magnetoscope, we may al- 
 ways determine the presence or kind of polarity acting on it. Thus, if such an instrument as that just 
 described, be glided along the surface of any given substance without any attractive or repulsive 
 effect being apparent, such a substance may be considered as non-magnetic. If, on the contrary, we 
 find both poles of the instrument everywhere attracted indifferently, then we may infer that the sub- 
 stance is a magnetic substance : such would be the case with a piece of common soft iron. Should we 
 find certain points attractive of one of the poles of the small needle, and repulsive of the other, then 
 we may infer that not only is the substance a magnetic substance, but that it has also polarity, or is a 
 magnet. 
 
 Magnetic influence or induction . — When a piece of soft iron is brought into contact with a magnetic 
 pole, it immediately acquires an attractive power, as if the magnetism of the pole had spread out and 
 pervaded the iron. In fact, if we examine a piece of iron thus circumstanced by means of the magneto- 
 scope, we find the same polarity continued throughout the iron ; it will everywhere attract one pole of 
 the magnetoscope, and repulse the opposite pole. If, however, we separate the iron from the magnet, 
 and retain it at a short distance from the magnetic pole, then a new case appears to arise : that portion 
 of the iron next the magnet will have an opposite polarity to that of the pole to which it is opposed ; 
 the two magnetic elements resident in the iron will, in fact, become separated ; one of them will be 
 sensible at the extremity next the magnet, and the other at its distant extremity : a result which we 
 
814 
 
 MAGNET— MAGNETISM. 
 
 might expect to follow from the repulsion of the similar elements and the attraction of the opposite 
 elements. This separation of the latent magnetism of the iron into its constituent elements has been 
 termed magnetic induction. It is altogether a temporary state or condition of the iron sustained by the 
 influence of a magnetic pole, and vanishes so soon as that influence is withdrawn. 
 
 In the communication of magnetism by the loadstone to hardened steel, and from one piece of steel 
 to another without limit, neither the loadstone nor the artificial magnet loses any of its inherent power , 
 nothing, therefore, appears to be communicated ; the whole result is entirely a species of molecular 
 excitation, or a calling into sensible activity certain forces already existiug in the magnetic substance, 
 and which, under ordinary circumstances, remain in a quiescent or neutral state. No means yet de- 
 vised have ever insulated these forces in such way as to enable us to obtain one of them only, independ- 
 ently of the other. We cannot, for example, produce a magnetic bar having a single pole ; for although 
 we touch one extremity of the bar only with one pole of the loadstone, still two poles will appear in 
 the bar, although the one induced by the presence of the other may not be so forcible. 
 
 Methods of communicating magnetism to steel bars. — The first means of imparting magnetism to 
 steel was, as we have already described, by contact with the armed loadstone or other magnet. A 
 more efficacious method, however, of magnetizing small needles or bars by simple contact, consists in 
 placing the bar or needle between the opposite poles of powerful magnets, as, for example, in the mag- 
 netic field S N, Fig. 2681, immediately between the poles S N. 
 
 We are indebted to Dr. Gowan Knight, F.R.S., a London physician, for the first important step in the 
 communication of magnetism to bars of steel. His method, as given in the Philosophical Transactions 
 for the years 1746 and 1747, vol xliv., is as follows : two powerful magnetic bars M M', Fig. 2685, are 
 placed in the same straight line, with their opposite poles N S very near each other ; the needle or bar 
 ns to be magnetized is laid flat on the surface of the bars, immediately over the opening N S, between 
 them. If the bar ns be a magnetic needle, having a cap for suspension, then the cap is allowed to 
 rest between the bars: if the surface be unimpeded by this, the bars M M' may be brought very near 
 each other. Things being thus disposed, the bars M M' are gradually withdrawn in opposite directions, 
 and immediately under the barsm; the result of which operation is, on the principles already ex- 
 plained, that each half of the bar s n being acted on by opposite polarities, the two magnetic forces resi- 
 dent in it become separated ; the pole N of the bar M attracts all the south polarity and repels the 
 north, whilst the pole S of the bar M' attracts all the north polarity and repels the south : hence a 
 final and permanent magnetic state is imparted to the bar s n, the position of the poles s n being the 
 reverse of the poles N S of the bars. 
 
 26 F 6 . 
 
 Small needles will become magnetized to saturation by one opei^ition of this kind performed on each 
 of its surfaces ; for larger bars, two or three, or more, repetitions are desirable. This method is very 
 effectual, especially for single bars, and there is not, perhaps, any better for certain purposes, even at 
 the present day. 
 
 After this method of Dr. Knight’s had become known and practised, M. Du Hamel, member of the 
 Royal Academy of Sciences at Paris, was led, about the year 1749, to a further and still more exten- 
 sive application of it. Two bars N S and T P, Fig. 2686, required to be magnetized, are laid on a ta- 
 ble jrarallel to each other, and their intended opposite poles united by pieces of soft iron N T, S P, so 
 as to form a closed rectangular parallelogram, as seen in the figure. The opposite poles n s of two 
 powerful magnets A B, either simple or compound, are then applied to the centre C of one of the bars 
 N S, and drawn away from each other in opposite directions C N, C S, being held all the while at an 
 inclination of about 40° : this operation is repeated several times ; the magnets A B are now either 
 reversed, or their relative positions changed, by turning them round ; they are then applied in a similar 
 way to the other bar P T, so as to bring the poles s n opposite to their former position : the same oper- 
 ation is now repeated on the bar T P, and this process is to be further repeated on each surface of the 
 bars T P, N S. M. Du Hamel’s method is effective and expeditious ; the elementary forces resident in 
 the bars being by tire joint operation of the magnets easily separated, whilst the union of the opposite 
 poles N T and S P by soft iron, further tends to increase the effect, by holding together, as it were, the 
 two separated magnetic elements, and thus allowing the exciting magnets A B to operate with more 
 considerable effect. 
 
 Bars of the horse-shoe form may be rendered magnetic in a similar way, by uniting their near ex- 
 tremities or intended poles with soft iron, and then drawing the magnets away from each other, com- 
 mencing at the centre of the curve, and terminating at each extremity. 
 
 A high magnetic development may be obtained in a series of straight bars, without the aid of pow- 
 erful magnets, by a successive touching in combination one with the other. We are indebted to Mr. 
 Canton for this process, which is as follows : 
 
 Having a set of 12 bars, however slightly magnetic, two of the series S' ISP, N S. Fig. 2687, are laid 
 
MAGNET— MAGNETISM. 
 
 31 £ 
 
 with reverse poles parallel to each other, and the rectangle closed by pieces of soft iron S N', N S', 
 about one-half the length of the bars, and of the same breadth, as in the method of Du Hamel ; the 
 remaining 10 bars are separated into two combined systems A B, of 5 bars each, placed on one of the 
 bars N' S', with their remote and opposite poles C in contact, and their lower poles n s somewhat open. 
 This arrangement being made, the bars S' N' and N S are rubbed with these systems in the way 
 already described, and being thus strengthened by the united powers of all the rest, are now removed, 
 
 2687. 
 
 c 
 
 and placed at the back of the others, as at A B, whilst the two interior bars of each system C s, C n, 
 are withdrawn, and subjected to the same operation as the preceding ; in this way we continue to 
 “trengthen each pair of bars by the acquired power of those last touched, until the whole become mag- 
 netized to saturation. This process is very useful when powerful magnets are not at hand ; for how- 
 ever weak may be the magnetic state of the bars, even although two of them only be slightly mag- 
 netic, we may from these render the whole series very powerful. 
 
 The combined systems A B may be temporarily bound together by a little common tape, and a small 
 block of wood placed between them, so as to support the whole in position during the process of mag- 
 netizing. 
 
 Besides these direct methods, we have other processes for obtaining a magnetic development in steel 
 and iron, of much practical importance. Marcel, so long since as the year 1722, observed that a bar of 
 iron acquired a temporary magnetic state by position alone ; and he succeeded in imparting magnet- 
 ism to a piece of hard steel placed on an anvil, merely by rubbing it with the lower end of a bar of 
 iron about 33 inches long, set upright upon the steel. The temporary magnetic state thus induced by 
 position in the iron bar is such, that the lower extremity, in these latitudes, becomes a south pole, and 
 the upper extremity a north pole ; and the forces are much increased by placing the bar in the direc- 
 tion of the inclined needle : in southern latitudes the reverse of this occurs — the lower extremity is 
 then a north pole, and the upper end a south pole. Mr. Canton, by an ingenious manipulation of this 
 kind, succeeded in communicating a weak degree of magnetism to steel by means of a common poker 
 and a pair of tongs, and from this magnetized his series of bars to saturation by the process we have 
 described : the bar to be rendered weakly magnetic was attached to the upper end of the poker by 
 means of thread, and the whole placed in the direction of the dipping needle ; whilst in this position 
 the bar was repeatedly touched with the closed extremities of the tongs, carried from one end of the 
 bar to the other, from below upward, the marked end of the bar being below. 
 
 Another method of developing magnetism in steel bars, without the aid of common magnets, consists 
 in subjecting the bar to sharp concussion. This principle was well known to Gilbert so long since as 
 the year 1570, who, in his celebrated work “De Magnete,” represents a blacksmith hammering a steel 
 bar in the position of the inclined needle. Smiths’ tools, such as drills, broaches, &c., which have under- 
 gone pressure and motion, are generally magnetic. When a steel jDunch is driven hard into iron, the 
 punch is not unfrequently rendered magnetic by a single blow. 
 
 In the Philosophical Transactions for 1738 we find an account, by Desaguliers, of iron bars ren- 
 dered magnetic by striking them sharply against the ground whilst in a vertical position, or otherwise 
 striking them with a hammer when placed in a horizontal position at right angles to the magnetic 
 meridian. Such bars attract and repulse the poles of the needle. According to Du Faye, whose ex- 
 periments are quoted, it is no consequence how the bar is struck : all that is required is to impart to 
 the bar a vibratory state whilst in a vertical position. 
 
 Availing himself of these facts, Scoresby, after a further and critical examination of the subject, 
 succeeded in obtaining magnetic bars of extraordinary power by percussion. In the course of these 
 inquiries, a considerable advantage was found to arise by striking the bar whilst resting in a vertical 
 position upon a rod of iron. A cylindrical bar of soft steel, 6 J inches long, and I of an inch diameter, 
 resting on stone, and struck with a hammer weighing 12 ounces, could only be made to lift about 
 grains ; whereas when resting on a bar of iron, and struck in a similar way, it lifted 88 grains. Scores- 
 by, in developing magnetism in this way by percussion, first struck a large iron bar in a vertical posi- 
 tion, and then laid it on the ground with its acquired south pole towards the north ; he then proceeded 
 to strike sharply with a hammer a soft steel bar, 30 inches long and an inch square, resting vertically 
 on the south pole of the iron bar. A second similar bar was treated in the same way ; then, placing 
 one of these steel bars vertically, he proceeded to strike upon them, as supports, a series of flat bars 
 of soft steel, 8 inches long, and \ an inch broad, and in a few minutes they had acquired a considerable 
 lifting power. The series of bars being now touched one with the other, after the manner of Canton 
 became very soon magnetized to saturation; each pah readily lifted 8 ounces. 
 
316 
 
 M A GNET — MAGNETISM. 
 
 Dr. Scoresby observes that large iron and steel bars are not absolutely requisite to the success of tliii 
 process, common pokers answering the purpose very well. 
 
 The next series of phenomena claiming attention, arise out of a property peculiar to natural and 
 artificial magnets, by which they tend, when freely suspended, to arrange themselves in a certain rela- 
 tive position to a wire carrying a current of Voltaic electricity. These phenomena have been hence 
 termed electro-magnetic , and although of sufficient moment and extent to come under a separate and 
 peculiar branch of physical science, yet so far demand a brief notice here, as constituting a very im- 
 portant property of the natural and artificial magnet. 
 
 With a view to a clear conception of these reciprocal magnetic and Voltaic actions, it is requisite to 
 understand that two plates of zinc and copper, z c, Fig. 2688, placed near each other in a vessel of di- 
 
 2690 . 
 
 2609. 
 
 lute acid, and connected by a metallic circuit c' S FT z', turned or directed in any manner, give rise, during 
 the solution of the zinc in the acid, to a peculiar electro-chemical action, by which a current of electricity 
 is supposed to flow from the zinc plate z in the direction of the small arrow, through the acid upon the 
 copper plate c , and from thence through the metallic circuit cc'SNz'z back again upon the zinc plate z. 
 A combination of this kind has been termed a Voltaic circle, and the metallic circuit c' S IT z' the 
 uniting wire. 
 
 This understood, let S IT be a perfectly straight portion of this circuit, which, as a standard of refer- 
 ence as to position, we will suppose to be in the direction of the magnetic meridian. Let p t be a mag- 
 netic needle, suspended below and parallel to FT S ; then, directly we complete the communications IT 
 z' z — S c' c with the zinc and copper plates zc, the needle p t varies from the meridian, and tends to 
 place itself across the wire IT S, and in such way that whichever pole of the needle is next the copper 
 plate c, that pole moves to the right hand, or towards the east. If, therefore, the current flow over the 
 needle from c to z , through the wire S IT, from south to north, and the observer be looking over the 
 wire in the same direction, then the south pole t, next the copper plate c, turns to his right hand, or to the 
 east, and the north pole p to his left hand, or west. If we suppose the position of the plates c and z 
 to be changed, and the direction of the current reversed, by connecting the extremity IT with c, and the 
 extremity S with z, so as to cause the current to flow from north to south, then these deflections are 
 also reversed. The south pole t now goes to the left hand, and the north pole p to the right hand — 
 that is to say, the north pole p being now next the copper plate, goes to the right hand. 
 
 Place the ueedle above, and parallel to the wire S IT, then the reverse of all the former deflections 
 will be obtained ; whichever pole of the needle is now next the copper plate, that pole moves to the 
 left hand, or west When the current, therefore, flows from south to north, the south pole t, which be- 
 fore went to the right hand, or east, now goes to the left hand, or west, whilst the north pole turns to 
 the right hand ; if we reverse the current, and cause it to flow from north to south, as in the last experi 
 ment, then these deflections are again reversed ; the north pole of the needle, being now next the cop 
 per plate of the battery, goes to the left hand. 
 
 If the needle be immediately in the plane of the uniting wire, on either side of it, no motion is ob- 
 tained in that plane ; but if it be suspended in a vertical plane, on a horizontal axis, so as to admit ol 
 a deflection of Inclination, then it tends to place itself across the wire as before. If the needle be on 
 the east side of the uniting wire, that is, on the right hand, taking the current and direction as at first, 
 then the south pole, next the copper side of the battery, dips below the horizontal plane, and the north 
 pole, next the zinc plate, rises. If the current be reversed, the deflections are also reversed. If the 
 needle be placed on the left hand, or west side of the uniting wire, then the south pole, next the copper 
 plate, rises, and the opposite north pole dips. By reversing the direction of the current, these deflec- 
 tions are again reversed. 
 
 It is apparent, from the successive directions of the bar as it becomes placed above, at the sides, or 
 below the wire S FT, that the force affecting the magnet is a force transverse to the pole of the bar, by 
 which, if the bar had complete freedom of motion in every direction, the poles would actually turn 
 round the wire, but in different directions ; and, conversely, supposing the bar fixed, and the wire S IT 
 carrying the current free to move, then those parts of the wire parallel to the magnet would rotate 
 about the magnetic poles in opposite directions, in a similar way. If both are supposed free to move 
 in any direction, then the wire and magnet would turn round each other, and such is really found to 
 happen, giving rise to a very important series of electro-magnetic actions. 
 
MAGNET— MAGNETISM. 
 
 or 
 
 oi 
 
 Let a magnetic bar M M', Fig. 2689, be bent so as to produce a short oblique portion at the middle 
 of the bar, with two vertical arms M M' ; poise it on a fine central point c, and let a wire N S be 
 placed near and parallel to one of the arms M. Then, supposing a descending current to flow from the 
 copper plate c, Fig. 2688, through the wire in the direction H S, upon the zinc plate Z, the magnet M 
 revolves about the wire N S, upon the central point c ; and if the north pole of the bar be uppermost, 
 the motion will be direct, or from the left hand to the right. 
 
 Conversely, if the magnet M be fixed as in Fig. 2690, and the wire N S be movable on a fine centre 
 o, then, on transmitting the current as before, through the wire N S, it immediately revolves about the 
 pole P of the magnet, with a direct screw motion, supposing the current to descend the wife, and the 
 pole P to be a north pole. To enable these motions to go on without disturbing the progress of the 
 current and the connections with the Voltaic plates, the movable parts dip into small cups and cisterns 
 containing mercury, and with which the plates of the Voltaic circle, Fig. 2688, communicate, as indi- 
 cated in the figures. 
 
 2691. 
 
 The tangential or transverse force, by which a magnetic pole is caused to revolve about a wire trans- 
 mitting a current of Voltaic electricity, is equally apparent when the magnetic bar itself becomes the 
 conjunctive wire of the battery ; so that an electrical current flowing over or through a magnetic bar 
 from one of its poles to the equator, or from the equator to either of the poles, causes such a bar to 
 revolve upon its axis, the requisite mechanical arrangements for motion being complete. 
 
 Let a magnetic bar, S P, Fig. 2691, be mounted vertically between two delicate centres ; the bar may 
 be about 18 inches in length, 1 inch wide, and of an inch thick. Let an electrical current be caused 
 to flow from either of the poles P S to the equator d, oj - from d to either of the poles P ; the bar will 
 immediately revolve upon its axis P S, the direction of the motion being such, that supposing the bar 
 to rest upon its north pole P, the centre d being in communication with the copper plate of the battery 
 C, and either or both of the poles P S in communication with the zinc plate Z, electrical currents w’dl 
 flow from the equator d to tihe poles, and the bar will revolve from left to right, as in the motion of the 
 hands of a watch, or a common right-handed screw. By reversing the communication with the Voltaic 
 plates, that is, placing the poles P S in connection with the copper plate, and the centre d with the zinc 
 plate, the electrical current will flow from the poles to the equator d. In this case, the direction of the 
 motion will be the reverse of the former ; it will be from right to left, or backward, as it were. 
 
 If the position of the magnet be changed, that is, if we place it to rest with its south pole below, 
 then, the communication with the Voltaic circle remaining as in the first instance, we also reverse the 
 motion. If now the communications be changed, as in the last instance, we again reverse the motion, 
 and obtain, as at first, a motion from left to right. 
 
 To facilitate the passing of the electrical current over the magnet, the bar is supported between fine 
 centres P S by a light vertical column fixed on a firm base ; a small ring or cistern of mercury d, also 
 supported from the vertical column, surrounds the equator of the bar ; the bar turns within this, and it 
 is connected with the mercury in turning by a small bent wire dipping into the cistern ; the lower 
 centre P turns upon an agate contained in a small cup at P, connected with the point Z' ; this cup con- 
 tains a small globule of mercury, to keep up the metallic connection with the magnet ; there is a simi- 
 lar globule in a small cavity at the upper end of the bar for the centre S ; this upper centre is sup- 
 ported by a wire extending from the head of the pillar Z Z r . It is here evident, that in connecting the 
 points C Z or C Z' witli the plates of the Voltaic circle, an electrical current will flow between these 
 points through C d S Z, or C d p Z', the direction depending on the respective connections with the zinc 
 or copper plate of the circle. 
 
 A recollection of the relative direction of the motions we have been describing will be facilitated by 
 keeping in mind the following simple formula: a descending current moves a north pole to the right 
 hand, or will give rise to a direct screw-motion ; from this simple fact all other relative motions are 
 easily determined. 
 
 The reciprocal action of a magnetic needle and uniting wire, together with the series of deflections 
 in given directions, have led to the invention of a very important magnetical instrument, termed the 
 Electro-magnetic Multiplier, or Galvanometer, by which extremely small magnetic and electro- magnetic 
 forces may be detected and measured. 
 
 It will be apparent, as already observed, that a current flowing both above and below a needle, is 
 
318 
 
 MAGNET— MAGNETISM. 
 
 opposite directions, deflects the needle in the same direction ; hence it follows that if a magnetic needle 
 p t, Fig. 2G92, be suspended on a delicate centre c, within the bite of a returning wire zdc, and the 
 extremities zcof the wire connected with the zinc and copper plates of the Voltaic circle by means of 
 two little cups containing mercury, then a current will flow longitudinally round the needle, both above 
 and below it, and in opposite directions, that is to say, in the direction c d above the needle, and in the 
 direction d z under it ; the effect of this will be to deflect the needle with twice the power by which it 
 would be deflected with a single current only, as in Fig. 2688. 
 
 If we imagine the wire zdc to be several times turned longitudinally about the needle, as in Fig. 
 2693, then the effect would be still further increased ; it would, in fact, become multiplied in proportion 
 to the number of turns of the wire, which would represent so many additional currents. It ii only 
 requisite to cover the wire with silk thread, or some other imperfect or non-conducting matter, so as 
 to avoid metallic communication between the coils, and oblige the current to traverse the whole length 
 of the wire. This is the principle upon which the electro-magnetic multiplier rests, and the delicacy of 
 the effect is such that the needle will become deflected by the immersion of two pieces of zinc and 
 platinum wire less than |th of an inch long, and -jL-th of an inch in diameter, in water slightly acidu- 
 lated. Fig. 2694 represents this instrument under one of its most perfect and delicate forms. Two 
 
 2694. 
 
 magnetic needles, with their poles reversed to each other, are fixed on a central rigid axis, so as to neu- 
 tralize the directive power of the needles, merely allowing a sufficient force to bring the whole into the 
 meridian. This system is suspended by two parallel threads of unspun silk r n, one of the needles 
 being within a rectangular coil of wire zdc, and the other needle immediately without it, and over the 
 upper part of the coil. The wire z c is covered with silk thread, so that the coils may not have metal- 
 lic communication, and the extremities p q are brought out near each other, and terminate in small cups 
 p q, containing a little mercury, for the better convenience of communicating a current to the coil from 
 any given source. The coils are separated a little near the centre, to allow the axis of the astatic sys- 
 tem of the two needles to pass through them. 
 
 The slightest current transmitted through the coil from p to q , or q to p, causes the needles to deviate 
 from their constant position. Both the needles, as is evident, will be impelled in the same direction ; 
 the lower needle being in the position just described, Figs. 2692 and 2693, whilst the upper needle, its 
 poles being reversed, is impelled in the same direction by the upper side of the coil. 
 
 The threads of the double or bifilar suspension r n, in tending to cross each other as the needles turn, 
 give rise to a reactive force, which may be set against the deflective force employed to measure it ; for 
 this purpose a graduated circle s s is fixed under or round the upper needle, so that the angle of deflec- 
 tion may be accurately estimated. If the earth’s directive force be completely neutralized by the re- 
 versed positions of the needles, then this would be the only force opposed to the deflective force ; i 
 not, then it becomes mixed with the little directive power left in the system, but which is generally so 
 small as not to be of much moment. 
 
 The instrument is set upon a convenient stand, and may be inclosed within a glass shade, the bifilar 
 suspension being sustained within a tube of glass. 
 
 Steel magnetized by the electrical current . — One of the many important results of these discoveries is 
 the means of imparting a high degree of magnetism to iron and steel, and to so great an extent as to 
 give a soft iron rod a lifting power of more than a ton. 
 
 We have seen that the electrical and magnetic forces are so related that the one is exerted at right 
 angles to the other. We derive from this elementary principle a means of disturbing the latent mag- 
 netic forces resident in magnetic substances, by which these forces become separated, and the body ren- 
 dered magnetic, precisely in the same way as effected by the contact of an ordinary magnet. 
 
 Let a long piece of copper wire be wound round a piece of glass tube of about an inch or less in 
 diameter, and from 6 to 10 inches in length, so as to produce a helix or spiral, A B, Fig. 2695, and mount 
 this spiral between two vertical supports, as represented in the figure. Place a perfectly neutral piece 
 of hard steel wire pn, of about Ath of an inch in diameter, or a large sewing needle within the helix, 
 and connect the extremities AB with the zinc and copper plates of the Voltaic circle, the steel pn will 
 become immediately magnetic ; in fact, each turn of the spiral causes electrical currents to flow in re- 
 verse directions above and below the steel. If the coils of the spiral be numerous and close, they maj 
 
MAGNET— MAGNETISM. 
 
 319 
 
 be regarded as parallel circles standing at right angles to the direction of the inclosed wire, and with 
 which toe axis of the helix may be made to coincide. The effect of a helix of this kind on a fine mag- 
 netic needle placed within it is so powerful, that with a strong Voltaic current the needle is frequently 
 caught up and retained on the axis of the spiral, as if liberated from the trammels of gravity. 
 
 The kind of polarity given to steel or iron thus circumstanced will depend on the direction of the 
 current with reference to the axis of the helix, and this again will depend on the connections with the 
 plates of the Voltaic circle and the direction in which the helix is turned. Now, the spiral may evi- 
 dently be turned either direct, like the threads of a common cork-screw, forming what is termed a 
 right-handed helix, or they may be turned in the reverse direction, in which case we have a left- 
 handed helix. 
 
 If we suppose the helix to be a reverse or left-handed helix, as in Fig. 2696, the current flowing from 
 c to 2 , round a small cylindrical steel needle or wire P N, and the coils standing in the direction of the 
 magnetic meridian c' z', so that the current may flow under the wire in the direction c' z’, from south 
 to north, as indicated by the dotted lines, and over the needle in direction c', from north to south, as 
 indicated by the full lines, then the positive pole P will be determined to the right hand, and the ex- 
 tremity P, of the wire next the copper plate c, will be a north pole : by similar reasons the opposite 
 extremity N will be a south pole, and next the zinc plate of the battery. 
 
 If we take a direct or right-handed helix and an inclosed wire PN, as in Fig. 2697, and transmit the 
 current as before from c to 2 , then the reverse of all this occurs ; the currents flow under the wire from 
 north to south in direction z'c', and over the wire from south to north in direction c' z'. Under these 
 conditions the positive pole P is determined to the left hand, so that the extremity P of the steel cylin- 
 der P N next the zinc plate becomes a north pole, and, by similar reasoning, the opposite extremity next 
 the copper plate c, a south pole. Supposing the current to be reversed and to pass through a direct 
 helix from left to right, the copper plate of the battery being to the left hand, and which is the ordi- 
 nary form of the experiment, the north pole will be always determined next the zinc plate, that is. to 
 the right hand 
 
 2GOO. 
 
 Zfi 08 . 
 
 ft will be useful to the student to remember as a general fact, that supposing, Fig. 2695, the observer 
 to be facing the north, N, and the helix A B placed transversely before him so that its axis may lie 
 east and west, then if the current be descending the coils of the spiral directly before him, the north pole 
 is determined to the light hand, and the south pole to the left. Reciprocally, if the current be ascend- 
 ing the cods of the spiral directly before him, then the south pole is determined to his right hand, and 
 the north pole to the left. Hence, with a direct helix, the north pole will be always found next the 
 zinc plate, and with a left helix next the copper plate. 
 
 The magnetic power developed in soft iron closely surrounded by heliacal coils transmitting electrical 
 currents all in the same direction is so great, that a curved iron rod, during the action of the battery 
 may be caused to sustain an enormous weight. The usual form of the experiment is as follows : 
 
 A cylindrical bolt of soft iron P T N, Fig. 2698, about an inch or more in diameter, and from 80 to 40 
 inches long, is bent into the horse-slroe form, as indicated in the figure. It is then surrounded by several 
 long coils of copper wire zTc, covered with silk or other iusulatiug thread, so as to interrupt all metal- 
 lic communication or coil with the other; one set of coils is superposed on another, and all the ends of 
 the wires P N on each side united into common terminations z c, to be connected w T ith the battery. 
 
 If, when the currents are passing through the coils, we apply a soft iron keeper P N, and cross the 
 projecting poles, it will be held fast with an enormous force, so that several hundred weight, W, may 
 be suspended without breaking the contact. An electro-magnet of this kind may become ^o powerful 
 as to support upwards of 2 tons. 1 
 
 . Instruments for indicating the presence and determining the polarity of magnetic forces, and measur- 
 ing their quantitative power under various conditions. — Instruments for indicating the mere presence of 
 magnetic force, and determining its peculiar polarity, may be termed, as before observed, magneto- 
 scopes ; those for its quantitative measurement, under various conditions, may be considered as mag- 
 netometers. J n 
 
320 
 
 MAGNET— MAGNETISM. 
 
 Magnetoscopes generally consist of light bars or needles, either suspended by a delicate flexible 
 thread, or attached to an agate or metallic cap, and set on a fine central point. Of these two forms of 
 suspension, the filar suspension is the most sensitive. The Rev. A. Bennet, F. R. S., employed fila 
 ments of a spider’s web, which proved so extremely delicate, that two small pieces of straw, placed at 
 right angles to each other, in the form of the letter T inverted, would, when thus suspended under a 
 closed receiver, turn towards a person coming within 3 feet of the glass, and would move so decidedly 
 towards wires merely heated by the hand, as much to resemble magnetic attraction. A fine and weakly 
 magnetic steel wire, suspended from a spider's thread of 3 inches in length, would admit of being twisted 
 round 18,000 times, and yet continue to point accurately in the meridian — so little was the thread sen 
 sible of torsion.* 
 
 Magnetometers . — The quantitative measurement of magnetic forces may be either direct applications 
 of equivalent weight, or any species of equivalent reactive power, as in the reactive force of torsion; or 
 may consist of indirect determinations of force, through the medium of certain relative effects, as in the 
 amount of deviation of a suspended magnetic needle from its line of direction by the influence of a mag- 
 net placed at a given distance from the needle. 
 
 Scale-beam magnetometer . — The common scale-beam, has been occasionally applied to the measure- 
 ment of magnetic forces. A small cylinder of iron or a magnet is to be suspended from one arm of the 
 beam, and counterpoised by weights in a scale-pan suspended on the opposite arm. The beam being 
 sustained on any convenient support in the usual way, a second magnet or iron is placed on the table, 
 immediately under this, and the attractive force at any given measured distance is estimated by addi- 
 tional weights placed in the scale-pan. 
 
 Much care is requisite in effecting this experiment. The beam should not be allowed any very con- 
 siderable play, but be limited in its motions by two vertical forked stops, one under each arm. If the 
 beam, with a given added weight in the scale-pan, be overset by the attractive force, and rest on 
 the stop, we may either increase the distance of the attracting bodies, or increase the wgjght, so as just 
 to catch the instant of the balance of the force. Or, supposing a given added weight in the scale-pan, 
 we may continue to approximate a magnet towards the suspended iron or other magnet over a divided 
 scale of distance, and catch the point at which the beam turns. 
 
 The bent lever, or any self-adjusting balance, may be also employed in a similar way to the measure- 
 ment of magnetic force. 
 
 The hydrostatic magnetometer . — This instrument, shown in its general form in Fig. 2700, and partially 
 explained in the following figures, is of such convenient and universal application to the measurement 
 and exhibition of elementary magnetic phenomena and forces, that a particular description of it appears 
 essential. 
 
 A light grooved wheel, W, Fig. 2699, about two inches in diameter, being 
 accurately poised on a firm axis, rn n, is mounted on the smooth circumfer- 
 ences of two similar wheels, mw, nw'. The extremities of the axis rn n are 
 turned down to fine long pivots, and whilst resting on the friction-wheels mw, 
 nw', pass out at mn between other small check-wheels, two at each extrem- 
 ity of the axis, so that the wheel W cannot fall to either side : great freedom 
 of motion is thus obtained. These friction and check wheels are set on points 
 or pivots in light frames of brass, and the whole is supported on short pillars 
 screwed to a horizontal plate or stage, as shown at A B, Fig. 2700. The stage 
 is sustained on a vertical column, A E, fixed to an elliptical base of mahogany, 
 
 E, supported on three levelling screws. 
 
 There is a short pin li, Fig. 2699, fixed in the circumference of the wheel 
 W, to receive an index of light reed, cut to a point, and movable over a gradu- 
 ated arc MN, placed behind the wheel, as represented in Fig. 2700: the 
 weight of this index is balanced by a small globular mass d, movable on a 
 screw in the opposite point of the circumference ; so that the wheel alone with 
 the index would rest in any position, or nearly so. The arc MN is a quad- 
 rant divided into 180 parts : 90 in the direction I M, and 90 in the direction 
 I N, the centre 0 being marked zero. Two fine holes are drilled through the 
 wheel, one on each side of the point h, for receiving and securing two silk lines, 
 ww ' : these lines pass over the circumference on opposite arms of the wheel, 
 and terminate in small hooks, t and w. A cylinder ot soft iron t, or a small 
 magnet, rather less than 2 inches in length and ijth of an inch in diameter, is 
 suspended by a silk loop from one of these lines, w‘, and a cylindrical counter- 
 poise of wood, a u, weighted at u, and partly immersed in water, is hung in 
 like manner from the oilier line, w. The weights, and altitude of the water, and of the vessel q con- 
 taining it, are so adjusted, that when the whole system is in equilibrio, the index b o is at zero of the 
 arc M N. With a view to a perfect adjustment of the index, the water-vessel q is supported in a ring 
 of brass at the extremity of a rod q, movable in a tube k, Fig. 2700 : this tube is attached to a sliding 
 piece b h, acted on by a milled head at h and a screw within the cylinder, which is fixed to the stage 
 AB, so that the water-vessel may be easily raised or depressed by a small quantity, and thus the index 
 be regulated to zero of the arc with the greatest precision ; for it is evident, by the construction of the 
 instrument, that the position of the index will depend on the greater or less immersion of the cylindrical 
 counterpoise a w, the weight of which being once adjusted to a given line of immersion, and a given 
 position of the wheel W and index O, any elevation or depression of the water-vessel q must necessarily 
 move the wheel. The counterpoise a u is about 1-J inch in length and full ’3 of an inch in diameter : a 
 small ball of lead is attached to its lowest part, in order to give it a sufficient immersion, and at the 
 
 2G99. 
 
 1 7i 
 
 Phil. Trans, for 1792, p. 86. 
 
MAGNET— MAGNETISM. 
 
 321 
 
 game time balance the iron cylinder t when the float is about half immersed in the water. With a view 
 to a imal regulation of the weight, a small hemispherical cup a is fixed on the head of the counterpoise 
 for the reception of any further small weights required. This counterpoise is accurately turned out ot 
 fine-grained mahogany, and is freed from grease or varnish of any kind, so as to admit of its becoming 
 easily wetted in the water. 
 
 The column A E supporting the stage A B consists of two tubes of brass, one, G, movable within 
 the other, E C, so that by a rack on the sliding-tube G, and a pinion on the fixed tube at C, the whole 
 of the parts just described may be raised or lowered through given distances, as shown by a divided 
 scale G, adjustabledo any point by means of a slide and groove in the movable tube G. The brass 
 tubes composing the column are each about a foot in length and an inch in diameter. 
 
 o 
 
 It will be immediately perceived, from the general construction of this instrument, that if any force 
 cause the cylinder t to descend, then the index h o will move forward in the direction 0 N, until such a 
 portion of the counterpoise a u rises out of the water as is sufficient to furnish, in the fluid it ceases to 
 displace, an equal and contrary force. In like manner, if any force cause the cylinder t to ascend, then 
 we have the reverse of this — the counterpoise obtains an equivalent increased emersion, and the index 
 moves in the opposite direction, 0 M. Thus if we place a weight of 1 grain, for example, on the iron 
 cylinder t, the index will indicate, in the direction 01, a given number of degrees equal to a force of 1 
 grain. If we double this weight, we obtain a force of 2 grains, and so on. The converse of this arises 
 on placing the weights in the cup of the counterpoise a u. We may thus reduce the indications to a 
 known standard of weight. It is further evident, that, whether we operate on the system by gravity 
 or by the attractive or repulsive force of a magnet, the indications of force are equally true. 
 
 If the instrument be well constructed, and the counterpoise freely wetted in the water, the march of 
 the index in either of the directions 0 IST or 0 M will correspond to the added weights. Thus, if 1 grain 
 Vol. II. — 21 
 
MAGNET— MAGNETISM. 
 
 322 
 
 gives 3 degrees, 2 grains will give 6 degrees, and so on. And thus we obtain a continual and knowt 
 measure of the force we seek to examine, within a given range of degrees of the arc, which will be 
 more or less extensive according to the dimensions of the cylindrical counterpoise, the intensity of the 
 force, and the rate of its increase. When we require to examine very powerful forces, or forces operat- 
 ing on the suspended iron t at small distances, it is requisite to increase the size of the counterpoise 
 lloat, the indications of which we may always find the value of in grains, as before. 
 
 Previously to suspending the cylindrical counterpoise a u, the iron cylinder t should be placed in 
 equilibrio on the wheel W, with an equal and opposite weight, as previously determined by an accurate 
 scale-beam, in order to observe if, when loaded with the whole, the wheel W and index are indifferent 
 as to position on any part of the arc, or nearly so. The instrument will be sufficiently delicate, if, when 
 loaded in this way with 350 grains, it is set in motion by something more than J a grain added to either 
 side. 
 
 In order to retain the wheel W, Figs. 2699 and 2700, in its position at the time of removing either of 
 the suspended bodies, a small brass prong is inserted at h into the arms of the circular segment M N, so 
 as to inclose the pin h carrying the index : the wheel is thus prevented from falling to either side. 
 
 The forces requiring to be measured are brought to operate on the suspended cylinder t through the 
 medium of induction on soft iron, or by a magnetic bar placed immediately under it, either vertically 
 or horizontally. In the vertical arrangement, shown in Fig. 2700, the magnet or bon is fixed against a 
 graduated scale S, by which the distance between the attracting surfaces or bodies is estimated. This 
 scale, together with the magnet H, is secured by light bands s, .of brass, united by a rod D K. The 
 lower band and rod D are both fixed to a stage D, movable between guide-pieces, and acted on through 
 a nut at q by a vertical screw P q, about 6 inches in length and |ths of an inch in diameter ; so that the 
 whole may be raised or depressed, and hence the suspended cylinder and magnet placed at any re- 
 quired distance apart. The regulation of tliis important element in the operation of magnetic forces is 
 hence provided for in two ways, viz., by the rack at G and the milled head at P, either of which may 
 be employed, as found most convenient. The scale S is of boxwood, 1 foot in length, fths of an inch 
 wide, and ^th of an inch thick : it is divided into inches, subdivided into tenths and twentieths of an 
 inch. About 6 inches of the upper part is divided in this way, viz., 3 inches on each side of a central 
 division which is marked zero ; the rest of the piece extends to the stage D. The magnetic bar H is 
 tied to the scale by compressing screws and simple brass bands, either fixed, as at D and K, or mov- 
 able, as at H. This adjusting apparatus is secured to a stout brass plate It, fitted by a dovetail into a 
 sliding piece v, forming part of the mahogany stand E, so that it may be removed at pleasure. The 
 brass bands and frames at D PI K are sufficiently capacious to inclose two bars together if required, the 
 superabundant space being filled when only one magnet is employed, either by a bar of wood or small 
 wedge pieces in the brass frame*. 
 
 When we require to examine the forces in different points of a moderate-sized magnetic bar, the bar 
 is laid in a small frame piece T Y, Fig. 2701, temporarily fixed by a compressing screw to the divided 
 scale S, in the way already described, the force on the suspended cylinder t being caused to operate 
 through a small cylinder of soft iron d, accurately fitted to the surface of the bar ; and thus, by sliding 
 the bar along in the holding-frame, we may get, approximatively, by induction on the iron d, the force 
 of any point in the bar. 
 
 When the bar is of considerable magnitude and weight, or we require to examine inductive forces, 
 the magnets may be placed on a narrow table, ab, Fig. 2702, supported on a central square pillar P, 
 fitted to the frame-pieces, K P, of the adjusting apparatus already described, so that the whole may 
 be raised or depressed through any given distance. In this case the divided scale S, which measures 
 the distance a between the attracting or repelling surfaces, is a detached piece fixed against one of the 
 perpendicular sides of a right-angled triangle, so as to be anywhere placed upright on the bar : the 
 
MANOMETER. 
 
 323 
 
 table a b also has a divided scale movable in a wide groove through its centre, by which any dis- 
 tance s between magnetic masses may be also shown. When the bars are very ponderous, two sup- 
 ports are required, one at each end of the table a b. 
 
 Inductive forces are examined vertically by fixing the masses by compressing bands against the 
 scale S, Fig. 2702, and of which we may have, if requisite, two or three in succession. 
 
 These arrangements put us in a position to note readily and simultaneously all relative distances and 
 forces under a great variety of magnetic and apparently complicated conditions. 
 
 We have been somewhat prolix in our description of this instrument, but not unnecessarily so. 
 There is scarcely any elementary experiment in magnetism which it does not completely and satisfac- 
 torily illustrate, besides furnishing quantitative measures of great importance to the mathematical in- 
 quirer into the laws and operations of magnetic force. See Electro-Metallurgy. 
 
 MAHOGANY. The beautiful reddish-brown colored wood, of which household furniture is now 
 chiefly made. It is a native of the warmest parts of America and the West Indies. It thrives in most 
 soils in the tropical climates, but varies in texture and grain according to the nature of the soil. On 
 rocks it is of a smaller size, but very hard and weighty, of a close grain, and beautifully shaded ; while 
 the produce of the low and richer lands is observed to be more light and porous, of a paler color, and 
 open grain ; and that of mixed soils to hold a medium between both. The tree grows very tall and 
 straight, and is usually four feet in diameter. On account of the difficulty of transporting the mahogany 
 timber from the forests, when the tree is of great thickness they cut it into short logs, otherwise the 
 great weight and bulk would be unmanageable with the restricted means available on the spot ; and 
 with the view of equalizing the burden or draft of the cattle, (oxen,) the logs are long in proportion to 
 their diminished thickness. The largest log ever cut in Honduras was of the following dimensions : 
 length 17 feet, breadth 57 inches, depth 64 inches; measuring 5421 feet of plank, of one inch in thick- 
 ness, and weighing upwards of 15 tons. 
 
 MANOMETER. An instrument for measuring the rarefaction and condensation of elastic fluids, but 
 especially that of the atmosphere. It differs from the barometer, which shows only the weight of the 
 superincumbent column of air ; whereas the manometer shows the density, which depends on the com- 
 bined effect of weight and the action of heat. It is sometimes called manoscope. Among the various 
 contrivances of this kind may be mentioned that of the Hon. Robert Boyle, which he calls a statical 
 barometer, which consists of a bubble of thin glass, about the size of an orange, which, being counter- 
 poised in an accurate pair of scales, rises and sinks with the alterations of the atmosphere. This instru- 
 ment, however, does not show the cause of the difference of density in the atmosphere, whether it be 
 from a change of its own weight, or its temperature, or both. The manometer constructed by Mr. 
 Ramsden, and used by Capt. Phipps in his voyage to the North Pole, was composed of a tube of small 
 bore, with a ball at the end ; the barometer being 2'97, a small quantity of quicksilver was put into the 
 tube, to take off the communication between the external air and that confined in the ball, and the part 
 of the tube below this quicksilver. A scale is placed on the side of the tube, which marks the degrees 
 of dilatation arising from the increase of heat in this state of the weight of the air, and has the same 
 graduation as that of Fahrenheit’s thermometer, the point of freezing being marked 32°. In this state, 
 therefore, it will show the degrees of heat in the same manner as a thermometer. But if the air be- 
 comes lighter, the bubble inclosed in the ball being less compressed, will dilate itself, and take up a 
 space as much larger as the compressing force is less ; therefore the changes arising from the increase of 
 heat will be proportionably larger, and the instrument will show the differences in the density of the air, 
 arising from the changes in its weight and heat. Mr. Ramsden found that a heat equal to that of boil- 
 ing water increased the magnitude of the air from what it was at the freezing point by A 1 /- of the 
 whole. Hence it follows, that the ball and part of the tube below the beginning of the scale, is of a 
 magnitude equal to almost 414 degrees of the scale. If the height of both the manometer and ther- 
 mometer be given, the height of the barometer may be determined also. 
 
 When used for measuring pressure above that of the atmosphere, the instrument (as usually con- 
 structed) is in all respects the same, except that the tube is not filled with mercury, but inverted, while 
 full of atmospheric air, into a reservoir of mercury, and the scale is differently marked. When the 
 pressure on the surface of the mercury in the reservoir is that of the atmosphere, the mercury will rise 
 in the tube nearly to the level of that surface, (but slightly lower, owing to the resistance of the air ir, 
 the glass tube.) As soon, however, as the pressure communicated exceeds that of the atmosphere, the 
 mercury will be forced up into the tube, and the inclosed air condensed, until its elastic resistance is just 
 equal to the pressure. The height of the mercurial column will of course vary with any variation of 
 pressure, and thereby indicate the degree of pressure at every moment by means of the scale, which is 
 divided, according to Mariotte’s law, into atmospheres, pounds, or the like. 
 
 The high degree of pressure to which the last-described form of manometer may be subjected without 
 error from friction or loss of mercury, the permanent elasticity, and the every-where existing and ex- 
 actly defined qualities of the material of resistance, (atmospheric air, or other fluids of the same nature,) 
 its comparatively small dimensions and convenient form, make it a very desirable instrument for meas- 
 uring the pressure of steam. As usually constructed, however, it has defects, which have prevented its 
 general use as a steam-gage. Among these defects were the coating and consequent opacity of the 
 glass tube, by the deposition of an oxide of mercury when acted on by the inclosed atmospheric air ; 
 the expansion and partial loss of air from within the tube whenever any partial vacuum was produced 
 in the boiler, and so allowing the mercury to rise higher in the tube with the same pressure ; its oscil- 
 lation, especially when there is a varying pressure, as in engines working expansively ; the almost 
 constant tendency of the condensed steam to insinuate itself between the mercury and the glass, 
 and to find its way into the tube above the mercury ; and the great inequality in the divisions ot 
 the scale, arising from the peculiarities of the law that governs the volume of aeriform fluids under 
 pressure. 
 
 The improvements by which these defects have been remedied, at the same time rendering it mor« 
 
324 
 
 MANOMETER. 
 
 2704. 
 
 cell 
 
 2703. 
 
 2700. 
 
 serviceable for determining pressures less than that of the atmosphere, have recently been made tht 
 subject of a patent to Mr. Paul Stillman, of Few York. 
 
 Fig. 2703 is the usual form of the patent manometer for showing a pressure up to eight atmospheres 
 Fig. 270-1 represents the form of one for showing a pressure up to twenty atmospheres. 
 
 Fig. 2705 is the form used for showing less than one atmosphere. The arrangement of 
 the glass tube is quite similar in all the forms usually given to the instrument. 
 
 Fig. 2706 is a longitudinal section through the centre of the glass tube, in which A is 
 the tube ; B is an iron piece in which the tube is firmly secured by means of the stuffing- 
 box G. It is screwed at one end to receive the brass case C, and in the middle to confine 
 it in the reservoir of mercury into which the lower end of the tube is to be immersed. 
 
 D D are scales divided into atmospheres, pounds, or inches of pressure, as desired. E E 
 are blocks to secure the scales in their proper places. F is a gland which protects the 
 lower end of the tube, and compresses the packing in the stuffing-box G. H is a cap or 
 plug loosely screwed into the gland to facilitate the operation of charging the tube, and 
 also, by admitting the mercury into the tube only through the interstices of the screw, 
 prevent its oscillation, and at the same time allow 
 the orifice to be made the full size of the tube 
 whenever it may be necessary to clean the tube. 
 
 In Fig. 2703 the reservoir for mercury is a deep 
 " with an iron tube communicating from the 
 
 cock at the bottom to the middle of the chamber above the surface of the mercury. In Fig. 2701 it is 
 divided, the glass tube being inserted into a cell of greater depth, while the reservoir of mercury is in 
 the bulb, to which a sufficient elevation is given to compress the gas within the tube to two or three 
 times the density of the atmosphere, according to the density of the steam of which it is to serve as the 
 gage. In this, as in the other form, an iron tube communicates the pressure from the cock below to 
 the surface of the mercury in the bulb above. The subdivisions of the scale are by this means much 
 more uniform and distinct than when used at atmospheric pressure only. 
 
 In all cases, the mercury should be seen above the junction of the tube with the tube-holder, so as to 
 indicate the initial pressure, or 0. In Fig. 2703 it is brought up by partially exhausting the tube at the 
 time it is erected. In Fig. 2704 it is forced up by the superincumbent weight of the mercury in the 
 bulb. The oxidation of the mercury within the tube is prevented in the latter form of the instrument 
 by charging the tube with nitrogen or hydrogen gas ; but in the former, on account of the difficulty of 
 preventing the admixture of atmospheric air, while exhausting a portion of the contents of the tube, for 
 the purpose above referred to, atmospheric air only is used, and a drop or two of naphtha or other 
 fluid answering the end, is introduced within the tube, on the surface of the mercury, to prevent the 
 oxidation. 
 
 When designed to show a pressure less than atmospheric, but not less than that shown by two inches 
 of mercury, the tube is to be perfectly filled with mercury, and inverted in the reservoir, and the press- 
 ure will be determined by the number of inches sustained above the level of the mercury in the reser- 
 voir below ; but if it is to be used for a pressure less than the weight of two inches of mercury — that 
 being the distance from the lowest visible part of the glass tube to the surface of the mercury in the 
 reservoir — it will be necessary to use the bulb shown in Fig. 2704, but with such an elevation only as 
 
MARBLE-SAWING MACHINERY. 
 
 325 
 
 will brine the surface of the mercury in it to a height equal to the lowest visible part of the glass tube ; 
 or it may be done equally well by using the form shown in Fig. 2104:, if a scale is properly made for 
 the purpose, and the bulb elevated so as to compress the air so high in the tube as to allow the mercury 
 to have sufficient fall without going out of sight, when the pressure of the atmosphere is removed from 
 the surface of the mercury in the bulb above. 
 
 It will be seen that either of these arrangements would resist the tendency of such partial vacuum as 
 is generally formed in steam-boilers, when they are allowed to cool down, from disturbing the quantity 
 of air within the tube of the manometer. 
 
 If the initial quantity of air or gas in. the tube be deranged by a change of temperature, or by any 
 other cause, it becomes necessary to know the extent of the variation occasioned thereby. To ascertain 
 this, (if inexpedient to correct it at once,) a simple arrangement is adopted, viz., 1st, to remove the press- 
 ure by closing the stop-cock and opening the small waste-cock between it and the reservoii this will 
 allow the mercury to fall to a place in which it will be at equilibrium with the atmosphere ; 2d, to note 
 the point to which it descends. The variation from the original place of 0 will be, in addition to the 
 pounds shown on the scale-plate, such part of the whole as the variation from 0 bears to the whole 
 length of the tube above 0. To determine this proportion, a series of decimals is placed on the scale at 
 fixed distances, and the one of these nearest to where the base of the column of air within the tube rests, 
 is to be used as a multiplier, by which the pressure of steam indicated on the scale is to be multiplied. 
 Their product, less the pounds of variation shown on the scale, will be the true pressure. Thus, for 
 example, if the mercury in the tube falls until the base of the column of air rests at the decimal *96, 
 which would be near to the place due to 1 pound pressure, and if, on opening the. communication to the 
 boiler again, it should rise to 130 pounds, this apparent pressure of 130 pounds is to be multiplied by 
 •96, and deduct from their product the 1 pound, thus giving as the true pressure 123'8 pounds, showing 
 a variation of 6'2 pounds. See Gage, Indicator. 
 
 MANGLE, house. Figs. 2T0T and 2108 exhibit a house mangle for swathing cloth, the action of 
 which is obvious. 2708 . 
 
 MAPLE-WOOD, is found growing in mountain districts, is indigenous to the United States, and val- 
 uable for its lightness ; and not being subject to warp or split, it will take any color, and a fine polish. 
 When green, it weighs 61 lbs. 9 oz. a cubic foot; and when dry, 51 lbs. 15 oz. 
 
 The bird’s-eye maple , from the beauty of its grain and the shades of its spots, is much employed for 
 veneering ; by sawing the timber nearly parallel with the concentric rings, the effect of its marking or 
 pencilling is much improved. In this country wheelwrights employ it, after giving it a seasoning for 
 two or three years ; and when constantly under water it will not readily perish. 
 
 MARBLE-SAWING AND POLISHING MACHINERY, worked by steam-power. Marble has. of 
 late years been extensively worked by machinery driven by steam-power ; the processes are closely 
 analogous in principle to those pursued by hand, but with various modifications of the apparatus, and 
 it is proposed to explain briefly some of the peculiarities of the machine processes. 
 
 In the simplest application of machinery to sawing marble, as for making one or two cuts in a large 
 block, the construction of the ordinary stone-saw is closely followed, but the frame is made much 
 stronger, of squared timber firmly bolted together, and stayed with chains ; to constitute three sides of 
 a rectangular frame, the place of the pole and tightening chain of the saw is occupied by two fixed 
 beams, and the saw is held and stretched by means of two clamps with screws passing through the ends 
 of the frame, and tightened by nuts on the outside. The saw-frame works between vertical guide-posts 
 to keep it upright, and it is reciprocated horizontally by a connecting-rod fixed to a crank driven by the 
 engine. The connecting-rod is attached to the frame by a loop, which can be placed at various heights, 
 so as always to keep the stroke of the connecting-rod nearly horizontal, notwithstanding the gradual 
 descent of the saw in the cut. 
 
 These saw-frames are sometimes made as large as 16 feet long and 10 feet high, for cutting huge 
 blocks of marble ; and to prevent the great weight of these frames from pressing on the cut, they are 
 suspended at each end by chains or slings which vibrate with the saw, and are connected with a coun- 
 terpoise weight, that is adjusted to allow of the necessary pressure for tire cutting, which is effected 
 
826 
 
 MARBLE-SAWING MACHINERY. 
 
 ■with sand and water supplied in the same manner as for the stone-saw used by hand, but the introduo 
 tion of the guide principle renders the chasing of the stone for the entry of the saw unnecessary. In 
 some cases smaller saws ot similar construction are used for cutting thick slabs into narrow slips, and 
 sometimes several cuts are made at once by an equal number of saw-blades, arranged in a rectangula” 
 frame that is suspended horizontally by vibrating slings, and works between vertical guide-posts. 
 
 In the horizontal sawing machine for marble patented by Mr. James Tulloeh, in 1824, the entire ar 
 rangements are combined in a very effective manner, for cutting a block of marble into a number ol 
 parallel slabs, of any thickness, at the one operation. The iron frame-work of the machine, shown in 
 Fig. 2109, consists of four vertical posts strongly connected together at the top and bottom, to form a 
 stationary frame from 10 to 14 feet long, 4 to 5 feet wide, and 8 to 12 feet high, within which the block 
 of marble to be sawn is placed. The two upright posts at each end of the stationary frame have, on 
 their insides opposite to each other, perpendicular grooves, within each pair of which slides up and down 
 a square vertical frame ; to the lower end of each of these slides is affixed a spindle carrying two guide- 
 pulleys, or riggers, upon which the horizontal saw-frame rests, and is reciprocated backwards and for- 
 wards. The saw-frame is thus traversed within the fixed framing, and supported upon the four guide- 
 pulleys of the vertical slides, which latter are themselves suspended by chains coiled upon two small 
 drums placed overhead. On the same spindle with the drums is a large wheel, to which a counterpoise 
 weight is suspended by a chain. The weight of the counterpoise is so adjusted as to allow the saw- 
 frame to descend when left to itself, and which thus supplies the necessary pressure for causing the 
 penetration of the saws. 
 
 The saw-frame is made rectangular, and from two to three feet longer than the distance between the 
 vertical slides, in order to permit of the horizontal traverse of the saws, which is from 18 to 20 inches. 
 To allow of the blades being fixed in the frame with the power of separate adjustment, every blade is 
 secured by rivets in a clamp or buckle at each end. The one extremity of the buckle embraces the saw, 
 the other is made as a hook ; the buckle at one end of the saw is hooked upon a horizontal bar fixed 
 across the end of the saw-frame, and the opposite end of the frame has a groove extending its entire 
 width, through which a separate hook, provided with a vertical tightening wedge, is inserted for every 
 saw, which thus admits of being replaced without deranging the position of the neighboring blades. 
 
 The distances between the saws, and their parallelism with the sides of the frame, are adjusted by 
 means of iron blocks made of the exact thickness required in the slabs of marble ; the blocks and blades 
 are placed alternately, and every blade is separately strained by its tightening wedge until it is suffi- 
 ciently tense ; the blocks are sustained between two transverse bars, called gage-bars, and are adowed 
 to remain between the blades to give them additional firmness. 
 
 The traverse of the saw-frame is given by a jointed connecting-rod, attached by an adjustable loop to 
 a long vibrating pendulum, that is put in motion by a pair of connecting-rods, placed one over the other, 
 and leading from two cranks driven by the engine. a 11 three connecting-rods admit of vertical adjust- 
 
MARBLE-SAWING MACHINERY. 
 
 327 
 
 ment on the pendulum. The connecting-rod of the saw-frame is placed intermediately between the 
 other two, but its exact position is regulated by the height at which the saws are working, as it is sus- 
 pended by a chain and counterpoise weight, which allow it to descend gradually downwards on the 
 pendulum with the progress of the cut, so as always to keep the connecting-rod nearly horizontal. 
 
 In the London Marble Works four of these sawing-machines of different sizes are grouped together, 
 with the driving-shaft and pendulums in the middle, and so arranged that each pair of saw-frames 
 reciprocate in opposite directions at the same time, in order to balance the weight, and reduce the 
 vibration. 
 
 Another mode of traversing the saw-frame sometimes adopted, is by means of a vertical frame than 
 is reciprocated horizontally on slides, and the connecting-rod, instead of being jointed, is fixed rigidly to 
 the saw-frame, and slides upon a vertical rod. Various other unimportant modifications in the construe 
 tion of the machines are also adopted. 
 
 One of the most difficult points in the application of these machines, was found to be the supplying 
 of the sand and water mechanically to the whole of the cuts at the same time. This is now success- 
 fully effected by the following arrangement. Above the block of marble to be sawn is fixed a water- 
 cistern, or trough, extending across the whole width of the frame, and measuring about 1 'foot wide, and 
 1 foot deep ; about 20 small cocks are arranged along each side of the cistern, and a small but constant 
 stream from each of the cocks is received beneath in a little box ; a sloping channel leads from every 
 box across the bottom of a trough filled with sand, which mingles with the water, and flows out in 
 separate streams, that are conducted to each of the saw-cuts. In the first construction of this appara- 
 tus for the feed, the sloping channels were led straight across the bottom of the sand-trough, but it was 
 then found that the water excavated little tunnels in the sand, through which it flowed without carrying 
 the sand down. This difficulty was overcome by leading the channels across the bottom of the trough 
 in a curved line, when viewed in plan. The form of the channels is shown in Fig. 2710, which repre 
 sents four channels cut across the middle of their length, to show 2710 . 
 
 their section, from which it will be seen that the channels are made 
 as a series of Gothic shaped tunnels, supported only on one side, and 
 open on the other for the admission of the sand ; the water flows 
 through these tunnels, and continually washing against the convex 
 side of the channel, undermines the sand, which falls into the water 
 and is carried down : to assist this action the attendant occasionally 
 stirs up the sand to loosen it. There is a sand-trough and set of 
 channels on each side of the water cistern, so that every saw-cut re- 
 ceives two streams of sand and water in the course of its length. 
 
 The saws having been adjusted to the proper distances for the required slabs, the saw-frame is raised 
 by means of a windlass and the suspended chains attached to the vertical frames, and the block of 
 marble to be sawn is mounted upon a low carriage, and drawn into its position beneath the saws, and 
 adjusted by wedges. The saws are then lowered until they rest upon the block, the counterpoise 
 weights are adjusted, and the mixed sand and water allowed to run upon the saw-blades, which are put 
 in motion by attaching the connecting-rod to the pendulum. The sawing then proceeds mechanically 
 until the block is divided into slabs, the weight of the saw-frame and connecting-rod causing them 
 gradually to descend with the progress of the cutting. 
 
 To allow the sand and water to flow readily beneath the edges of the saw-blades, it is desirable 
 that the horizontal frame should be slightly lifted at the end of each stroke. This is effected by making 
 the lower edges of the frame, which bear upon the guide-pulleys, straight for nearly the full length of 
 the stroke, but with a short portion at each end made as an inclined plane, which on passing over the 
 guide-pulleys lifts the frame just sufficiently to allow the feed to flow beneath the saws. 
 
 For cutting slabs of marble into narrow pieces, such as shelves, and which is effected by hand with 
 grub-saws, a machine called a ripping bed is employed, in which as many cuts as may be required in 
 the one slab are effected simultaneously, by an equal number of circular saws with smooth edges, re- 
 volving vertically, and fed, as usual, with sand and water. This machine consists of a bench about 12 
 or 14 feet long, 6 or 7 wide, and about 2 feet 6 inches high ; upon the top of the bench is fixed two rails, 
 upon which a platform, mounted on pulleys, is drawn slowly forward by a weight. The horizontal axis 
 carrying the saws revolves about 9 inches above the platform, and to insure the rotation of the saws, 
 the axis is provided with a projecting rjjb or feather extending its whole length. The saws are made 
 as circular plates, about 17 inches diamener when new. The saws, or cutters, are clamped between two 
 collars about 6 inches diameter, fitted so as to slide upon the spindle, and be retained at any part of its 
 length by side screws. 
 
 The saws having been adjusted to the required distances for the widths of the slips to be cut, and 
 fixed by the side screws, the slab of marble is imbedded in sand upon the platform, and the edge of 
 every saw is surrounded on one side with a small heap of moist sand. The saws are then set in mo- 
 tion, so as to cut upwards, and the platform is slowly traversed under the saws by the weight, which 
 keeps the slab of marble constantly pressing against the edges of the revolving saws, until the slab is 
 entirely divided into slips. 
 
 "When the saws are new, they nearly reach the upper surface of the platform, and a moderate thick- 
 ness of sand, just sufficient to form a bed for the slab of marble, raises it high enough to allow the 
 6aws to pass entirely through the thickness of the slab ; but as the saws are reduced in diameter by 
 wear, it becomes necessary to employ a thicker layer of sand, or to use a supplementary platform to 
 raise the slab to the proper height. To avoid this Inconvenience, an improvement lias been recently 
 introduced by mounting the axis of the saws in a vertical slide, which is adjusted by a rack aud pinion, 
 so as to allow the edges of the saw to penetrate exactly to the required depth. 
 
 Circular pieces of marble, such as the tops of round tables, and other objects, from about 6 feet diam 
 eter to the small circular dots sometimes used in tesselated pavements, are sawn to the circular form 
 
328 
 
 MARBLE-SAWING MACHINERY. 
 
 by means of revolving cylindrical cutters, constructed on much the same principle as the crown saws 
 for wood. The slab to be sawn is placed horizontally on a bench, and the axis of the machine works 
 vertically above it in cylindrical bearings, which allow the spindle to slide through them, so as to be 
 elevated or depressed according to circumstances. The spindle is suspended at the upper end by 
 a swing-collar attached to a connecting-rod, that is jointed to the middle of a horizontal lever. 
 The weight of the vertical rod and cutter supplies the pressure for the cutting, and the whole ii 
 raised for the admission of the work by a rope attached to the end of the lever, and passed over 
 a pulley. 
 
 For circles of small diameter, the cutters are made as hollow cylinders of sheet-iron, of various 
 diameters, and each attached by screws to a circular disk of cast-iron,” as shown in section in Fig. 2711. 
 The cutter is screwed on the lower end of the spindle, just the same as a chuck on a lathe mandrel, 
 except that the spindle is placed vertical instead of horizontal. To insure free access for the sand and 
 water beneath the cutter, one or two notches, about three-quarters of an inch wide, are generally made 
 in the lower edge. 
 
 For large circles, the apparatus is made strong, and 
 the vertical spindle is fitted at its lower extremity with a 
 circular plate, to which is bolted a wooden cross, shown 
 in plan in Fig. 2711, and in elevation in Fig. 2713; the 
 cross has radial grooves about 18 inches long, near the 
 outer extremities of the four arms. The cutters consist 
 of detached plates of iron, from G to 18 inches long, of 
 various widths, according to the thickness of the work. 
 
 The cutters are curved as segments of a cylinder, of the 
 particular diameter they are required to cut, and are each 
 riveted to a clamp that passes through the radial groove, 
 and is retained by a wedge. The number and length of 
 the cutters is solely a matter of convenience, as a single cut- 
 ter, when put in rotation, would make a circular groove, 
 and several cutters are only employed in order to expedite 
 the process. But eveiy different diameter requires a 
 different curve in the cutters, and which must all be placed 
 at exactly the proper distance from the centre of rotation. 
 
 The horizontal bench upon which the marble is laid, is 
 generally a temporary structure, adjusted to suit the 
 thickness of the object to be sawm. Works of large di- 
 ameter are seldom more than one or two inches thick, but 
 those of small diameter are frequently much thicker, and 
 sometimes three or four thin pieces are cemented upon 
 each other, and cut at one operation. Short pillars are 
 sometimes sawn out of an irregular block in a similar 
 manner, instead of being chipped and turned. And it 
 has been proposed that long cylinders, and tubes of stone, 
 should be cut with cylinders of sheet-iron of correspond- 
 ing length, put in rotation, and supplied with sand and water. 
 
 Marble works of small and medium size, are ground flat upon horizontal revolving laps, after the 
 same general method as that pursued by the lapidary, but with a proportionate increase of size in the 
 lap, which is supplied as usual with sand and water. The laps for marble works are made as circular 
 plates of cast-iron, from fi to 14 feet diameter, and about 3 inches thick when new; they are mounted 
 in various ways upon vertical spindles, so that their upper sides or faces may be about 2 feet 6 inches 
 above the ground. Across the face of the lap, or, as it is called, the sanding plate, one or two strong 
 square bars of wood, faced with iron, are fixed so that their lower sides may just avoid touching the 
 face of the lap, and their edges present perpendicular faces, from 5 to 6 inches high, at right angles to 
 the face of the lap. The wooden bars serve as stops to prevent the work from being carried round by 
 the lap, and also as guides to insure the work being ground square. 
 
 The piece of marble is laid flat upon the lap, with the face to be ground downwards, and the side of 
 the work in contact with the guide-bar. Water is allowed toSdrip upon the plate from a cistern fixed 
 above, and small quantities of sand are thrown on as required. During the progress of the work the 
 workman leans upon the marble, the position of which is shifted occasionally to expose both the work 
 and the lap to an equal amount of wear, and prevent the formation of ridges, but which is less likely 
 to occur with iron laps used for grinding large surfaces of marble, than when small objects are applied 
 upon lead laps, as by the lapidary and mechanician. 
 
 The one side of the marble having been reduced to a flat surface, the work is turned over to grind 
 the adjoining face, and the first face is held in contact with the perpendicular side of the guide-bar, in 
 order to present the second face of the work to the lap exactly at right angles to the first. When two 
 pieces of similar size are to be ground each on the one face and two edges, as for the upright sides of 
 a chimney-piece, the two pieces of marble are cemented together back to back with plaster of Paris, 
 (a process that is called lining^) and the pair are ground as one piece on all four faces ; in this case the 
 flat sides are first ground parallel to each other, or of equal thickness on the two edges, and the latter 
 are then ground square by placing the sides in contact with the guide-bar. 
 
 When the lap is of moderate size, one guide-bar only is employed, and it is fixed across the diameter 
 of the plate, whicli then allows of two workmen being employed on the opposite sides ; but large 
 grinding plates sometimes have two or three bars placed at equal distances across the face, and four or 
 six workmen may then be employed at the same time upon separate pieces of marble. 
 
MARBLE-SAWING MACHINERY. 
 
 329 
 
 The sand and water are continually thrown from the lap by the centrifugal force, and the large siz«. 
 of the works sometimes applied prevents the use of a rim standing up above the level of the lap te 
 catch the wet, as used by lapidaries. Every workman, therefore, stands within a kind of trough like a 
 box, about three feet high, without a top or back ; the troughs serve as a protection to the workmen, 
 who would otherwise be exposed to a continued shower of sand and water. 
 
 The surfaces of large slabs are in some cases ground upon revolving plates ; in this case the axis is 
 placed entirely beneath the surface of the plate, somewhat as in Fig. 2714, and the slab is traversed 
 by two men over the face of the plate to grind it equally, but the machine next described is better 
 adapted for large slabs of marble requiring tolerable accuracy. 
 
 Large slabs of marble and stone are ground very accurately in a machine patented by Mr. Tulloch 
 and called a grinding bed. In this machine, represented in Fig. 2714, the slab to be ground is placed 
 
 2714. 
 
 horizontally upon a moving bed, and the grinding is effected by sand and water, by means of t large 
 flat plate of iron resting upon the surface of the slab. The two surfaces are traversed over each other 
 with a compound motion, partly eccentric and partly rectilinear, so as continually to change their rela- 
 tive positions. The machine consists of a frame about 9 feet long, 6 feet wide, and 8 feet high ; about 
 2 feet from the ground is mounted a platform, that is very slowly reciprocated horizontally for a dis- 
 tance of from 1 to 2 feet, according to the size of the slab, by means of a rack and pinion placed be- 
 neath, and worked alternately in both directions. 
 
 Above the platform are fixed vertically two revolving shafts, having at their upper extremities hori- 
 zontal toothed wheels of equal diameter, which are driven by means of a central toothed wheel keyed 
 on the driving-shaft. The two vertical shafts are thus made to revolve at equal velocity, or turn for 
 turn, and to their lower ends are attached two equal cranks, placed parallel to each other ; the extremi- 
 ties of which, therefore, describe equal circles in the same direction. To these cranks the iron grinding 
 plate or runner is connected by pivots fitting two sockets placed upon the central line of the plate. 
 The cranks are made with radial grooves, so that the pivots can be fixed by wedges at any distance 
 from the centre of the cranks. When the machine is put in motion, the grinding plate is thus swung 
 round bodily in a horizontal circle of the same diameter as the throw of the cranks, which is usually 
 about 12 inches, and consequently every portion of the surface of the grinding plate would describe a 
 circle upon the surface of the slab being ground, if the latter were stationary. But by the slow recti- 
 linear movement of the platform, the slab is continually shifted beneath the plate, so as to place the 
 circles, or rather the cycloids, in a different position ; and it is only after many revolutions of the cranks 
 that the same points of the surfaces of the grinding plate and slab are a second time brought in 
 contact. 
 
 The grinding plate is raised for the admission of the slab by means of four chains suspended from a 
 
330 
 
 MARINE STEAM-ENGINE. 
 
 double lever, and attached to the arms of a cross secured to the centre of the upper surface of the plate, 
 ■which is thus lifted almost like a scale pan. For slabs that are much thicker or thinner than usual, the 
 principal adjustment is obtained by the removal or addition of separate beds, or loose boards, laid upon 
 the platform to support tire slab at the proper height. Slabs that are too large to be ground over the 
 whole surface at the one operation, are shifted once or twice during the grinding, to expose the surface 
 equally to the action of the grinding plate. 
 
 The necessary pressure for grinding, is given by the weight of the horizontal plate, which is sup- 
 ported almost entirely by the work, as the pivots of the cranks merely enter the sockets, and allow the 
 plate to descend when left to itself. For delicate works a counterpoise weight is attached to the 
 double lever so as to regulate the pressure on the work. 
 
 The sand and water are applied to the grinding surfaces in much the same manner as in the iron 
 runners used by hand, previously described. The grinding plate is made on the upper side with a 
 raised rim like a tray, and the bottom of the tray is perforated with numerous holes about 1 J inch 
 diameter arranged at equal distances apart. The sand and water are thrown into the tray at intervals 
 in small quantifies, and run through the holes and between the surfaces of the slab and grinding plate, 
 which are thus uniformly supplied with the feed that ultimately makes its escape around the edges of 
 the grinding plate. . 
 
 Various qualities of sand may be employed according to the perfection of surface required, and very 
 flat surfaces are produced by this machine. The grounding or smoothing of the best works is effected 
 with a succession of fine emeries, with which the surfaces may be made very smooth, and almost 
 polished ; but from motives of economy, the grounding of ordinary works is more frequently completed 
 by hand, with grit-stone and snake-stone, before the work is finally polished on another machine. 
 
 Eectilinear mouldings in marble are wrought by machinery in a manner altogether different from the 
 hand process of working mouldings, in which, as previously described, nearly the whole of the material 
 is removed with chipping chisels, and the surfaces of the mouldings are only smoothed by abrasion. In 
 the machine process, on the contrary, the whole of the material is removed with revolving grinders, by 
 which the work is reduced to the required form, and left smooth at the one operation. 
 
 The machine for working rectilinear moulding, or as it is called the moulding bed , closely resembles 
 in its construction the ripping bed described previously, except that the frame carrying the revolving 
 grinders is provided with the power of vertical adjustment by a screw placed beneath, in order to raise 
 the grinder to the proper height to suit the thickness of the marble, and that instead of the grinders 
 being thin circular sheets of iron, they consist of solid cylinders of cast-iron turned to the counterpart 
 forms of the required mouldings. Indeed the ordinary ripping bed is occasionally used for working 
 mouldings on large works, and when it is provided with the vertical adjustment for elevating or 
 depressing the axis to any required position, the ripping bed is equally suitable for working mouldings 
 but as the latter are in general only required on slips of marble only a few inches wide, a narrow ma- 
 chine is usually employed for the purpose. 
 
 MARINE ENGINES, Steam. Marine engines may be divided into two broad classes, viz: beam 01 
 lever engines, and direct acting engines. These may be either condensing or non-conaensing engines , 
 the former, however, are the most extensively used. With the exception of small screw-propellers and 
 tow-boats, and steamers on the western waters, the condensing or low-pressure engines are almost 
 

 in. -urn 
 

 
 
 
 
MARINE STEAM ENGINE. 
 
 331 
 
 •wholly used in this country. The terms high and low pressure are in general used to designate respeo 
 tively the non-condensing and condensing engine, although the terms are not in truth sufficiently distinc* 
 tive, as the condensing engine may he, and in connection with the expansion principle, frequently is, 
 used with what may he called high steam. What would he considered in this country a low pressure 
 steam, say 40 lhs. to the inch, would be considered in England as high-pressure. 
 
 These two classes admit of subdivision into many varieties, hut may, for all practical purposes, he 
 confined to the following system of arrangement : 
 
 Beam-engine, 
 
 Side-lever. 
 
 r 
 
 Direct-acting engine... - 
 
 Vertical 
 
 Oscillating, 
 
 Rotatory. 
 
 Square engine. 
 
 Steeple engine. 
 
 Trunk engine. 
 
 Gorgon. 
 
 F airbairn. 
 
 Double-cylinder engine. 
 
 The Direct-Acting Engines differ from the beam-engine simply in the method of taking the power 
 from the piston-rod. In the one the head of the piston-rod is connected either directly with the crank, 
 or by means of a connecting-rod or rods ; in the other, the working-beam or great lever, vibrating on 
 its centre, receives at one end the power from the piston-rod through the modifying action of “ parallel 
 motion ” rods, or plain slides, and communicates it to the crank-shaft by a connecting rod attached to its 
 other extremity. 
 
 The Side-Lever Engine is a modification of the 
 
 of the marine engine, this form of engine is ordinarily understood, unless otherwise specified. For al- 
 though other forms of engines may become of as much importance to steam navigation, certain it is 
 that at this day no engine has been found to equal it in point of general efficiency. The description of 
 engine called oscillating is, however, coming into favor, from other considerations to be noticed subse- 
 quently. 
 
 I’assing to the varieties of the direct-acting engine, already defined, we find that the attempt to pro- 
 duce engines more compact and of less weight and bulk, has extended the examples of this class of en- 
 gines into an almost endless variety of modifications. Scarcely any two are alike ; and in our classifi- 
 cation above, we have retained only tnose whose features are sufficiently distinctive to admit of general- 
 ization. Some engineers regard those engines only as direct-acting, where the piston itself seizes the 
 crank, without the intervention of any connecting-rods. Such are the trunk and oscillating engines ; 
 but the classification we have used is simple, and sufficiently minute for all purposes. 
 
 In the first species of the direct-acting engine, namely, the vertical, the paddle-shaft is directly over 
 the axis of the cylinder ; but the method has the disadvantage of admitting only a short stroke and a 
 short connecting-rod, and requires that the height of the axis above the bottom of the cylinder should 
 be at least three times the length of the stroke. Thus one of the extremes, too short a connecting-rod, 
 too short a stroke, or a paddle-axis too high above the floor of the vessel is incurred. 
 
 1c this country the square engine, the first variety of the vertical engine, has its cylinder immedi- 
 
332 
 
 MARINE STEAM ENGINE. 
 
 ately over the axis and cranks, to which motion is communicated from the cross-head of the piston bj 
 means of side-rods, the air-pump being worked by a separate beam connected with the cross-head by pro- 
 per links ; but this is equally unsuited to sea-going steamers on account of the height of the cylindei 
 above the paddle-shaft. 
 
 To obtain the object sought without incurring these evils, many descriptions of engine have heel 
 contrived ; among others the steeple engine, so called, where the piston-rod is made forked, so as, pass- 
 ing round the shaft, to rise above it to a considerable height, from which again descends the connecting- 
 rod to the crank. Figs. 2716 to 2721 illustrate the principle. The top of the piston-rod carries a four- 
 armed cross-head h k, on each end of which stands a pillar hh ; these four pillars again unite in another 
 quadruple cross-head, sustained upright by a vertical guide ; and it is from this summit that a connect 
 ing-rod descends to the crank K. 
 
 After passing through a great variety of phases the steeple engine appears to have settled down mt« 
 the two following shapes. In figs 2720 and 2721 the piston-rod is seen united to a triangular frame, 
 from the apex of which the connecting-rod descends to the crank. In fig. 2722 this frame is shown to 
 be square, and fig. 2719 is the side view of both varieties. 2723 2724 
 
 Another method of accomplishing the direct connec- 
 tion without encumherirlg the deck is called the trunk 
 engine,. The axis is placed at the height of half the 
 stroke, or more, above the cylinder, and a connecting- 
 rod unites immediately the crank-pin with the centre of 
 the piston. In this way the connecting-rod, passing 
 through the top of the cylinder, would allow the steam 
 to escape but for a large trunk or casing with which it 
 
 is surrounded, and which, passing through a chasm of large area conceived to 
 be steam-tight, rises and falls w T ith the piston to which it is attached. In fig. 
 
 2724, A A is the cylinder ; to its piston is attached a trunk B, which works 
 through a stuffing box in the cylinder cover ; to the piston the connecting-rod 
 c c is attached. Fig. 2723 represents the top of the cylinder A A, with its 
 stuffing-box and the trunk. 
 
 These engines were first used for marine purposes with vertical cylinders, 
 and were again introduced into use by Penn, of Greenwich, with horizontal 
 cylinders. The first application of it was to H. M. S. Encounter, a vessel of 
 360 hoi'se-power. The cylinders are horizontal, and connected at once to the 
 screw-shaft. These engines make between 78 and 80 revolutions per minute, 
 which was sufficient to propel the ship about eleven knots. They were fitted 
 with locomotive slides, and worked with two eccentrics. The air-pumps, like 
 the cylinders, were horizontal ; and indeed all the parts of the engines were 
 ns low as they possibly could be, for the purpose of bringing the machinery 
 
 below the water line. 
 
 This form of engine was used by the Messrs. Kemble, for the steamers “ Pioneer ” and “ City of Pitts 
 ourg.” In these the cylinders are again brought back to the original vertical position, and form, not- 
 withstanding, a most compact form of engine. 
 
 The Gordon, Fairbairn, and the double-cylinder engines are English varieties of direct-acting engines 
 extensively used abroad, but little used in this country; they deserve a passing notice, as illustrative 
 of the efforts made to reduce the dimensions of marine engines within the least possible limit. 
 
MARINE STEAM ENGINE. 
 
 333 
 
 The principle of construction of the Gorgon engines will be clearly seen by reference to fg. 2725, which 
 represents a section of one of such engines ; and the several parts, for simplicity .sake, are represented 
 
 omy bylines. Here AB CD represent the cylinder, F is the centre of the shaft, directly over the 
 middle of the cylinder ; I E is a section of the piston ; I H the piston-rod, working steam-tight in u 
 etuffing-box at K ; H G is the connecting-rod, and G F the crank It is easily seen that as the piston is 
 
334 
 
 MARINE STEAM ENGINE. 
 
 forced up and down by tlie steam, the crank will be made to revolve, and consequently cause the paddle- 
 wheel to rotate. The remaining parts of the engine will be readily understood : L is the condenser, M 
 the air-pump, N the hot well, a and b are the foot-valve and delivery-valves respectively. There are twc 
 particulars deserving special notice in this engine, viz. : the slides for admitting the steam and allowing 
 it to escape, and the parallel motion, or the means of keeping the piston-rod in its vertical line. It is 
 observable that there are four slides, viz. : A, B, C, and D, two of which, A and C, are for allowing tlia 
 ingress of steam, and the other two, B and D, for allowing it to escape to the condenser L. The follow- 
 ing is an outline of the parallel motion: II 0 is a beam called the “rocking-beam,” one end of which 
 
 2727 
 
 o ; 
 
 / 
 
 i 
 
 
 T 
 
 1 
 
 a 
 
 2728 
 
 ,tted to the upper extremity H, of the piston-rod. P Q is a vertical frame, called the ‘rocking- 
 standard ; ” the lower end of this is connected with some convenient point Q, about which it can move, 
 and the upper end P will therefore describe a small circular arc about Q; but this arc will be so small 
 that it may be practically looked upon as a straight line. T S is a bridle-rod, secured at one end T to 
 the framework of the engine, and at the other to the rocking-beam. If, now, these rods have the pro- 
 per proportions, the motion of H will be vertical. The rocking-beam is continued along to 0, and the 
 air-pump rod is fitted to it by means of the interme- 
 diate rod R 0. The air-pump rod is kept in a vertical 
 line by means of guides. 
 
 Fig. 2726 represents an outline of the Gorgon 
 engine. 
 
 The chief peculiarity of Fairbairn’s direct-acting 
 engines is in the parallel motion, which is somewhat 
 similar to that of the Gorgon engines. 
 
 The dotted lines, fig. 2727, represent the Gorgon 
 engines. H P 0 is the rocking-beam ; H the point to 
 which the piston-rod and connecting-rod are attached ; 
 
 P the point of attachment of the rocking-standard ; 
 then, to construct Fairbairn’s parallel motion, let the 
 rocking-standard P Q be inverted, as in the figure, so 
 as to hang down from a point Q' in the entablature of 
 the engine. In the Gorgon engines, H P is prolonged 
 to 0, as before described, and the air-pump is worked 
 from this extremity ; but in Fairbairn’s engines the 
 radius-gear S T will be produced to some point O', and 
 O' T serves as the beam for working the air-pump. 
 
 The steam is admitted and allowed to escape by 
 means of a slide-valve, worked by an eccentric. 
 
 The four main parts of each engine, viz. : the cyl- 
 inder, slide-valves, condenser, and air-pump, form a 
 square, and thus occupy little space. 
 
 Fig. 2728 represents in outline one of the Fair- 
 bairn engines. 
 
 Maudslay's Double-Cylinder Engines. In the fore- 
 going direct engines the connecting-rod is necessarily 
 shorter than it would have been if side-levers had been used • and consequently the force exerted on the 
 
MARINE STEAM ENGINE. 
 
 335 
 
 2729 
 
 crank alters more suddenly as tlie motion is alternated from the up to the down stroke, and vice versa , 
 than would have been the case had the connecting-rod been longer. 
 
 Now, in most direct engines a long connecting rod is an impossibility ; for the distance from the shaft 
 
 to the bottom of the vessel being limited,, the depth 
 of the cylinder, the radius of the crank, and the 
 length of the connecting-rod, must all be accommo- 
 dated to it. Messrs. Maudslay and Field proposed 
 to remedy it by adapting two cylinders to each en- 
 gine, instead of one ; the cylinders having one con- 
 necting-rod between them. In figs. 2729 and 2730 
 A and A 2 are the two cylinders of one of the en- 
 gines ; a a 2 the piston-rods ; these rods are connected 
 together at their upper extremities by the cross-piece 
 
 2731 
 
 BCD, called (from its form) the T-plate ; the lower end C of the T-plate is attached to the connecting- 
 rod C E, which again being connected with the crank E F communicates with the paddle-shaft F. The 
 condenser G is underneath the cylinders. It is clear that if steam be admitted below both pistons at the 
 same time, the pistons, in rising, will force up the T-plate, and with it the connecting-rod, &c . ; and 
 
 conversely these will again descend as the 
 2732 piston is forced down. Hence the working 
 
 HjHHl ^ ^ ^ J L part t ^ ie engine can be comprehended. 
 
 It remains to be shown how the steam is ad- 
 mitted to both cylinders simultaneously. 
 Looking at the plan of the figure, the cir- 
 cle S represents a slide-valve, different in 
 form from the common slide-valve, inasmuch 
 as it is circular instead of being semicircular ; 
 it has one upper and lower face in contact 
 with the ports of the cylinder A, and one of 
 each in contact with the cylinder A 2 , so that 
 as the valve is raised or depressed, the steam 
 is admitted above or below both pistons at 
 the same instant of time. FI is the air- 
 pump, the bucket of which is worked oy 
 the beam K L moving round the centre I. 
 
 Fig. 2731 is an outline elevation of the 
 double-cylinder engine. 
 
 In the oscillating engines the connecting- 
 rod is altogether dispensed with, the piston- 
 rod being attached directly to the crank; and 
 because the piston-rod from this mode of at- 
 tachment, must either be bent when motion 
 ensues, or the top of the cylinder must move 
 laterally, this is provided for by allowing the 
 cylinder itself to vibrate in a small arc, ef- 
 fected by casting trunnions on to the cylinder near its middle, as an axis upon which it oscillates. 
 
336 
 
 MARINE STEAM ENGINE. 
 
 Fig. 2732 will give an idea of the appearance of the oscillating engine. 
 
 Many nautical men, and some engineers, have objected to oscillating engines on account of the move- 
 ment of the cylinder, which, they imagined, would become a formidable evil in the case of a vessel roll- 
 ing heavily at sea. These objectors do not seem to have remarked that the rolling of the cylinder is 
 neither dependent upon, nor proportionate to, the rolling of the ship, but is regulated exclusively by the 
 movement of the piston ; and it is difficult to see why a mass of matter, in the form of a cylinder, 
 should be more formidable or intractable in its movements than a similar quantity of matter in the 
 form of a side-lever, or in any other shape whatever. It has also been objected against the oscillating 
 engine, that the eduction passages are more tortuous tnan in common engines, so that the steam gets 
 out of the cylinder less freely. We do not believe such to be the fact, if the comparison be made with 
 the common ran of marine engine ; and in practice, no diminution of efficacy from this cause is appre- 
 ciable. All the objections that have been raised to the oscillating engine are hypothetical ; they are 
 anticipations of defects to he found out in large engines on the oscillating plan, and would probably be 
 plausible enough to carry some weight, were it not the fact that they have been completely controverted 
 by experience. The remark, indeed, is heard sometimes even yet, that the oscillating method may do 
 very well for small engines, but is of doubtful efficacy for large ones. But the definition of large en- 
 gines has been continually changed, to escape the contradiction experience afforded, and that size is, in 
 every case, decided to be large, which just exceeds the size of the oscillating engine last constructed. 
 The grounds of this skepticism, however, are now being fast contracted; and, indeed, experience has 
 now demolished every objection that theory had raised. Some persons have apprehended that it would 
 be difficult in large oscillating engines to obtain sufficient surface of trunnion to prevent the trunnions 
 from heating; yet we have never been able to learn that any heating of those bearings has been found 
 to occur in practice, and it appears probable that any such disposition would be resisted by the cooling 
 effect of the steam passing through them, which, though hot, is of greatly inferior temperature to that 
 of a hot bearing. It does not appear to us, however, that the trunnions may not be made with any 
 amount of surface that is thought desirable, but we believe the proportion adopted by Messrs. Penn have 
 been found adequate, and are generally adopted in this country. 
 
 Rotatory Engines are engines for obtaining a motion round an axis by the direct action of the steam, 
 without involving the necessity of reciprocation. Some of them operate on the principle of reaction of 
 which the engines of Avery and others may be taken as specimens ; others operate on the principle 
 of impulse; a third kind trusts to the intervention of some liquid to produce the desired effect, as in 
 the mercury engine of Watt and the wheel of Amonton ; while in the fourth class the piston moves in a 
 circle round the axis. It is impossible to give any enumeration even of the numberless schemes for 
 rotatory engines that have at various times been projected ; but none of them have been applied with 
 any prospect of success to the purposes of navigation, and in their present state, need scarcely be ranked 
 as marine engines. 
 
 MARINE STEAM-ENGINE, of one hundred and forty-five horse-power. By Caird & Co., Greenock 
 The following figures illustrate very fully the form and construction of marine engines made by Messrs. 
 Caird & Co. of Greenock, for the steam-packets Actteon and Achilles, and also for the royal mail-packet 
 Urgent, still plying betwixt Liverpool and Dublin. The drawings were made from the engines of the 
 Actteon, since lost on the West-India station ; but in order to render them more complete, and therefore 
 more acceptable to the engineer, the expansion-geer subsequently applied to the engines of the Achilles 
 has been embodied. It may also be remarked, that by proportionally reducing the scale of the draw- 
 ings, they will be found to agree in every respect, beyond a few very slight modifications of a technical 
 kind, with the larger class of engines, since constructed by the same spirited firm for the W est-India 
 mail-packets Clyde, Tay, Tweed, and Teviot, of 225 horse-power each engine. The figures may thus 
 be regarded as giving a general representation of the form of marine engines built by a firm to whose 
 engineering skill the profession is indebted for a design of engine equally remarkable for elegance of 
 appearance and compactness of arrangement. In lightness of material it is no doubt surpassed by the 
 recent introduction of malleable-iron framing, and direct-action; but in the class to which it belongs, 
 known as side-lever engines, it exhibits a massiveness of appearance and an economy of weight which, 
 in combination with equal strength, has not hitherto been surpassed. 
 
 Enumeration of the figures. — Fig. 27144- exhibits a complete side elevation of the engine, showing the 
 general design and arrangement of the framings, and the relative positions and connections of the work- 
 ing parts; the valve, expansion, and starting geer, parallel motions, and situation of the pumps. In this 
 view the side of the vessel is supposed to be removed and the engine seen in situ. 
 
 Fig. 2715 is a plan of the sole-plate of the engine with all the parts removed, but showing the position 
 and provision for fixing the steam-cylinder bottom and valve casing, the hot-well, placed on the top of 
 the condenser, the air-pump, and the soles of the main framing. 
 
 Fig. 2716 is a general plan of the engine, exhibiting very fully the starting and eccentric geer, the 
 mode of working the pumps, the direction and position of the steam-pipe, and mode of connecting the 
 diagonal framing ; also the horizontal relation of the valve and expansion geer. 
 
 General description. — Sole-plate and condenser. — The sole-plate, marked A A, with the condenser U, 
 consists of a single casting, double-ribbed on the under side, to give it additional strength and rigidity. 
 For facility of fitting it is provided with fitting-strips on its upper surface ; these are faced true to re- 
 ceive the soles of the maiji frame and cylinder bottom, which are fitted upon it metal to metal, aud 
 consequently are likewise-provided with corresponding fitting-strips, faced in the same manner. The 
 sole-plate is firmly secured to the keelsons of the vessel by sixteen strong malleable-iron bolts marked 
 a in the elevation, and the recesses for which are similarly designated in the plan of the sole-plate The 
 middle of the plate, falling between the two keelsons, is depressed to allow the condenser and its ap- 
 pendages to stand lower in the vessel than they otherwise would, as shown in the general section. 
 
 Framing. — The main framing of the engine consists of four strong fluted columns, cast pair and pair 
 

 
Pi rrr 
 
 ■ 
 
 X 
 
 j 
 
 
 i 
 

MARINE STEAM-ENGINE. 
 
 337 
 
 with their soles and entablatures. The soles, as above observed, are fitted upon the sole-plate metal to 
 metal, and are secured to it by bolts and keys, for which snugs are cast on the sole- plate. The entab- 
 lature is completed by two cross-beams corresponding in form with the sides, into which they are fit tec 
 and secured by bolts. The form of their cross-section is shown in the general section of the engine. 
 
 The upper or crank framing consists likewise of four columns cast pair and pair with their soles and 
 entablatures ; but in this case there are no cross pieces, the two sides being simply braced together by 
 two strong malleable-iron stays marked c. One of these passes between two strong lugs cast on the 
 back columns near the top, and the other between the cheeks of the diagonal framing marked 0. The 
 crank-framing rests on the entablature of the main frame to which it is fitted, and secured by bolts and 
 by two centre keys in each sole, driven on the right and left of a dovetail snug cast on the entablature 
 of the lower frame, and which enters a similarly formed but larger recess in the sole of the upper frame 
 — an arrangement which is clearly shown both in the general elevation and section. This framing is 
 further secured between the ship’s beams by the strong stays b b cast upon the entablatures. These 
 stays usually abut against cast-iron face-plates, bolted upon the paddle-beams at the points of contact, 
 but they are neither bolted nor otherwise fixed to the facings, but are left free to slide vertically upon 
 them in obedience to any spring which the vessel may have when under way, and which is often con- 
 siderable, especially in a rough sea. The crank-framing is also braced to the steam-cylinder by the 
 diagonal framing C C, consisting of two strong parallel struts cast upon the inner columns of the crank- 
 framing, from which they spring. These struts terminate in rectangular flanges, answering to similarly 
 formed projections cast on the cylinder on opposite sides of the valve-casing at top ; and to these they 
 are carefully fitted metal to metal, and secured by bolts, as partially shown at d in the elevation 
 and plan. 
 
 The principal use of the crank-framing, and that from which it takes its name, is to support the c> ank- 
 sliaft. This is accomplished in each of the engines by two plummer-blocks, one on each side of the 
 crank, secured by bolts and keys on the entablatures of the frames. The soles of the plummer- 
 blocks are in this, as in all highly finished engines of the same class, likewise faced and fitted metal 
 to metal. 
 
 Steam-cylinder . — The steam-cylinder E is cast open, and with broad and strong flanges at both ends. 
 It is placed upon a separate bottom piece, flanged like the cylinder, to allow of their being bolted to- 
 gether. This bottom piece being truly faced, above and below, is secured to the sole-plate of the 
 engine by strong bolts, and rusted. The lower end of the cylinder being truly faced is similarly 
 fitted upon and secured to the upper flange of this bottom piece, so that the whole may be perfectly 
 steam-tight. 
 
 The interior of the cylinder is bored as truly as possible of a uniform inside diameter of sixty-two 
 inches. The cover d' which, as will be observed from the section, is cast hollow, is fitted by turning 
 and grinding, into the upper end to nearly the depth of the steam-port. On the inside is a circular re- 
 cess to receive the heads of the bolts of the junk-ring of the piston ; and the exterior plate is expanded 
 by a strong flange to the same diameter as the flange of the cylinder, to which it is secured by bolts. 
 In the centre is formed the stuffing-box through which the piston-rod ascends. 
 
 The projecting corner pieces marked d are those to which the diagonal framing is attached ; they 
 are faced both on their horizontal and vertical surfaces, so that the corresponding flanges, in which 
 the struts of the framing terminate, may be fitted truly upon them. The projecting valve facings 
 are cast of a piece with the cylinder. These are carefully dressed and the whole surface of both exactly 
 reduced to the same plane ; and to complete them, a carefully finished facing of brass, but of less 
 breadth, (two inches,) is applied steam-tight round each of the ports, and projects on each side, by 
 runners of a length corresponding to the length of the ledgings of the valves. The outlines of these 
 facings are indicated in the view above referred to, and the transverse form in the general section of 
 the engine. 
 
 The piston . — The body of the piston consists of a single hollow casting, strengthened by radiating 
 feathers, with a strong eye in the centre to receive the piston-rod. The under side is a portion of a 
 sphere answering to the curvature of the bottom of the cylinder. The upper side in like manner is 
 convex to its junction with the ring, which is horizontal, and corresponds to a horizontal part round 
 the inside of the cover, within which the cover is a segment of a hollow sphere of the same radius as 
 the top of the piston. By making these parts of a curvilinear section, they are better secured from 
 rupture by changes of temperature ; and the piston being symmetrical in its outlines with the cover and 
 bottom, the loss of steam due to the clearance is reduced to a minimum. 
 
 The under side of the piston only is cast of a diameter equal to that of the cylinder, the deficiency on 
 the upper side being made up by the junk-ring. This ring is fitted steam-tight, first by turning 
 and subsequently by grinding. Packing-rings, consisting of two thicknesses, made up of overlapping 
 segments, are likewise fitted into their place between the junk-ring and the flange corresponding on 
 the under side of the piston, and are rendered steam-tight by the same means. The whole of these 
 thicknesses, composing the edge of the piston, are simultaneously turned of a uniform diameter, pre- 
 cisely equal to the internal diameter of the cylinder, in which they are intended to work steam-tight ; 
 but as this condition would endure only for a short period, however carefully and exactly the fitting 
 might be effected, were no provision made for compensating the wear incident to the continued motion 
 of the piston, and especially under variations of temperature, as in starting, the packing-rings are ren- 
 deied capable of adjusting their diameter to that of the cylinder, by springs placed behind them. The 
 springs employed in this piston are of a U-form, placed vertically, the strong side bearing upon the 
 piston, and the elastic side against the adjacent ends of two of the segments. The number of springs 
 and segments is thus necessarily equal, and so arranged that every segment is supported at each end 
 by a spring. By this means the pisten is made to work in the cylinder steam-tight, and to accommo- 
 date itself to any slight variations due to the contraction and expansion of the materials; and likewise 
 to compensate for wear of its own circumference and that of the cylinder. 
 
 Vol. II.— 22 
 
338 
 
 MARINE STEAM-ENGINE. 
 
 The junk-ring is secured in its place by bolts and nuts ; the nuts are placed in recesses provided 
 for them in the metal of the piston, and the bolts are screwed into them from the outside. The heads 
 thus project on the surface of the ring, and would come into contact, at the end of the up-stroke, with 
 the cylinder cover, but for a circular recess formed in it for their reception, as before noticed. 
 
MARINE STEAM-ENGINiE. 
 
 339 
 
 eve and the thickness of the rod thereby effectually binding the latter to the piston. For convenience 
 of inserting the key a recess is left in the upper plate of the piston, which is afterwards filled, to prevent 
 the steam gaining admission to the hollow interior of the piston. 
 
 Piston cross-head and connections . — The piston-rod, ascending through a packed stuffing-box, is 
 inserted .into an eye, bored a little smaller than its own diameter in the cross-head I, equidistant 
 from the two extremities ; and is then fixed by two gibs and cotter in the usual manner. The 
 cross, head has two journals turned on each of its ends, separated from each other by ruffs of an inch 
 
 2715. 
 
 2710. 
 
 >c> 
 
 breadth. By these journals the radius-bars KKand the side-rods J J are connected with the cross- 
 ... ' VJ e side-rods are fitted upon the exterior journals, and descend to the corresponding extrem- 
 
 ities of the side levers M M, to which they are also flexibly attached. Their connection at the 
 crossdiead as will be observed from the elevation, is by solid eyes formed in the ends of the rods 
 and bushed, the brasses being retained in their places by the collars of the cross-head, with the assist- 
 ance o a^ey rearing against the back of the lower brass ; but the connection with flie side-levers is 
 effected differently. Here the brasses are placed within strong malleable-iron straps, bent at the mb’ 
 
340 
 
 MARINE STEAM-ENGINE. 
 
 die of their length till their projecting ends fit closely upon the rectangular ends of the side-rods, ii 
 which they are secured by a gib and cotter. This species of connection, technically known as the butt- 
 end and strap , and universally adopted in like circumstances, provides for any slight wear of the brasses 
 for should these become too large, they can be brought closer together by driving the cotter more 
 tightly, the holes through which the gib and cotter pass being so disposed in the strap and butt that 
 the gib shall only be in contact with the ears of the strap and the cotter with the butt on its under 
 edge. The holes in both strap and butt being thus of greater breadth than the gib and cotter together, 
 the connection admits of adjustment to the extent of the difference, and no further, for then the edges 
 of the holes being in the same plane, the relative positions of the strap and butt will not be altered by 
 any subsequent action upon the cotter. 
 
 The side-levers are divided at their extremities at the point of connection with the side-rods J J and 
 the links jj, which connect them with the cross-tail. The joints are completed by strong malleable- 
 iron pins which pass through the jaws of the levers, and the bushes of the straps which are placed be- 
 tween them. These centre pins are turned with a little taper on the parts which pass through the 
 levers, and the holes made for their reception are accurately bored to the same diameter and ground. 
 The studs are driven in tightly from the outside, and secured in their places by riveting at the opposite 
 extremity. 
 
 Both levers are suspended upon the same axis called the main centre, M', which passes through and 
 is fixed in the sides of the condenser. It will be observed that the eye of the lever is fitted with brasses 
 which can be tightened as they wear by a pair of cotter-keys, parsing through the boss and bearing 
 against the back of the under brass. Inside, and bearing against the shoulder of the boss, is a ring of 
 malleable iron, of sufficient breadth to cover the margin of the eye to fully an inch beyond the circum- 
 ference of the brasses, thereby preventing the lever from deviating inwards: and to prevent it from 
 sliifting its position outwardly, a plate of the same external diameter is applied by a strong bolt screwed 
 into the end of the main centre. 
 
 The side-levers are connected with the connecting-rod 1ST by means of the cross-tail O and links jj. 
 The connecting-rod passes through an eye at the middle of its length, and is fixed by two gibs and a 
 cotter, in the same way as the piston-rod is attached to the cross-head, wdiile the links are connected in 
 the same manner as the side-rods, except that the upper ends do not admit of adjustment, being simply 
 riveted in the eyes. The attachment of the connecting-rod with the crank is likewise by a butt-end and 
 strap, the cotter of which is tightened and maintained in its place by a screw and nuts. The crank-shaft Q 
 rests, as before observed, on pedestals fixed upon the entablature of the crank-framing, and is prevented 
 from moving on end by ruffs on the outsides of the pillows, and by the shoulders of the crank-brasses 
 inside. 
 
 It may be noticed that the piston-rod, side-rods, cross-head, main centre-shaft, cross-tail and links, 
 connecting-rod, and crank-shaft are all formed of the best malleable iron, and turned and pared to the 
 requisite forms and dimensions. 
 
 The parallelism of the piston-rod is maintained when the piston is in motion, by the two radius bars 
 Iv K, by the radius levers//, fast upon the ends of the shaft L, called the parallel-motion shaft, and by 
 the parallel bar h. The ends of the radius bars K K, on the cross-head are formed with solid eyes, 
 fitted with brasses, the inner of which are tightened by keys, in the same manner a9 those of the side- 
 rods which are attached at the same points. The eyes at the opposite ends, which work upon studs in 
 the radius levers // are formed in the same way, but are smaller, and have the outer brasses adjusta- 
 ble by screwed-pins g g. The length of the bar thus admits of slight adjustment between its centres, 
 to compensate for errors of workmanship and wear of the bushes. The parallel bar h is also attached 
 by a solid eye and stud to the lever /, and admits of still more extensive adjustment at its lower end. 
 This bar, it will be observed, is formed in two pieces, with the contiguous ends screwed right and left, and 
 embraced by a long nut similarly screwed. By turning this nut to the right or left it is obvious that the 
 upper and lower ends will be made to approach or recede, and the distance between the centres be 
 thereby diminished or increased. The upper end of the rod is formed with a solid eye bushed, and the 
 lower with a butt-end and strap in the usual way; it -is attached to the exterior side-lever by a malleable- 
 iron stud inserted into a rectangular eye formed in the latter. 
 
 The disposition of the flexible points of these connections being such, that in every position of the 
 piston the angles of the parallelogram formed by the part of the side-lever comprehended between the 
 stud of the rod h and the junction of the side-rod, opposed to the radius bar K, and by the parallel 
 bar h and the side-rod J, shall change proportionally, always preserving the same constant ratio, it fol- 
 lows that the piston-rod cross-head will move constantly in the same place and the parallelism of the 
 piston be thereby maintained. 
 
 The parallel-motion shaft L is supported by two plummer-blocks, resting on the entablatures of the 
 small pillar-framing D. This framing, called the parallel-motion framing, consists of four columns, 
 cast, like the larger framings, pair and pair, with their soles and entablatures, and with provision on 
 the latter for bolting and keying the pedestals. The soles rest upon oblique flanges cast on the 
 .diagonal framing C 0, to which they are secured by bolts and keys. 
 
 The valves and valve-geer. — The valve casing F is cast of a semi-cylindrical form, corresponding to 
 the form of the valves, which are of that kind designated, in accordance with their outline, short 
 D-slides. 
 
 The casing is fitted steam-tight and bolted to the side of the cylinder by projecting flanges cast on 
 both for that purpose ; and also to the sole-plate over the recess T', shown in the general elevation 
 The flat side, as will be observed from the general section, occupies only about a third of the whole 
 length equidistant from both ends, and is cast with projecting flanges, which are carefully fitted steam- 
 tight between the ends of the projecting faces of the cylinder. These faces thus project inside, but 
 are concealed by the circular part of the casing, in which, it will be observed, when the cover is applied, 
 there is no communication with the external atmosphere ; through the passages T it communicates 
 
MARINE STEAM-ENGINE. 
 
 341 
 
 with the condenser U, and through the steam-ports with the cylinder. The steam-pipe G likewise opens 
 into it, and a communication is thereby effected with the boilers. 
 
 The valves, as already noticed, are of the kind known as short D-slides. There are two of these, 
 one to each port of the cylinder. The backs are turned truly circular, and the faces are planed and 
 ground to the brass facings of the ports, so that they may slide upon them steam-tight, and with 
 as little friction as possible. They are kept tight against the faces, and also rendered steam-tight in 
 the casing by hemp packings, introduced through the packing-porta cast in the casing. These pack- 
 ings are covered by the packing-rings which are pressed against them by set pins acting in nuts 
 between the packing-rings and the port-covers, as fully shown in the general section. These set pins 
 can be tightened at pleasure by a box key, inserted through holes formed in the covers, and filled with 
 hollow plugs, which can be withdrawn when necessary. 
 
 The planes forming the faces of the valves are slightly less than double the breadth of the port, but 
 the circular parts are necessarily much larger. The faces and backs are connected by strong dia- 
 phragms, through which pass the ends of the rods which couple the two valves together. These rods are 
 turned to an exact length between the ruffs, against which the contiguous sides of the diaphragms bear, 
 and are kept fast in their places by nuts upon their protruding ends. They are stiffened at the middle 
 of their length by a cross-stay. A strong stud is inserted downwards in the middle of the diaphragm of 
 the upper slide, and is retained in its place by a nut on the end projecting below. The upper end is 
 formed with strong projecting lugs, between which the enlarged square end of the valve-spindle is re- 
 ceived, and retained by a strong square pin which passes through the lugs of the stud and the end of 
 the spindle, thereby forming an inflexible joint at the point of connection. 
 
 The valve-spindle passing through a packed stuffing-box in the cover of the valve casing, is 
 attached by means of a small cross-head and side links, to the lever n. This lever is fast upon the 
 transverse shaft m, which has its bearings immediately under those of the parallel-motion shaft in the 
 framing D. On the opposite end of the lever n , is fixed a weight q, sufficiently heavy to counterpoise 
 the weight of the valves.. This weight is connected with the shaft S, called the starting -shaft , by two 
 small levers s s. These levers are fast upon the shaft S, but are flexibly connected to the axis of the 
 weight q, by two short connecting-rods jointed to each. The shaft S is carried on pedestals fixed upon 
 the cheeks of the diagonal framing 0 C, and has a short lever crank keyed upon the end projecting to 
 the inside of the engine. A long lever is fitted to this fixed piece by a hollow boss which passes upon 
 the tail, but, being required only occasionally, it is not fixed, that it may be removed when not in use, 
 and for that reason it is not shown in the drawings ; but supposing it applied, it is plain that by moving 
 it towards the right and carrying the shaft S with it in the same direction, the balance weight q will be 
 elevated and the valves depressed. The reverse action will produce the reverse effect by again lower- 
 ing the weight and raising the valves. Now, observing in the section that the lower steam-port of the 
 cylinder is open to communication with the condenser, and that the upper port communicates only with 
 the interior of the casing, if the weight q be raised until the valves descend through a space equal to the 
 breadth of the faces, it is clear that the conditions will be reversed, and that the upper port will be 
 opened to communication with the condenser, through the passage T, and that the lower passage will be 
 shut, and the lower port will communicate with the interior of the casing. 
 
 Upon one end of the traverse-shaft m, is a crank-arm, upon the pin of which a gab formed in the 
 end of the compound rod 1 1, called the eccentric rod, rests. This rod, which consists of two bars of 
 malleable iron stiffened by diagonal braces, is attached at its base to the two opposite lugs of the 
 eccentric ring R, which works freely upon the eccentric embraced by it, and which revolves with the 
 crank-shaft of the engine ; consequently, supposing the crank to revolve, the rod 1 1 will at the same 
 time receive an alternating rectilineal motion, which being transferred to the crank-lever of the 
 traverse-shaft m, will cause the ends of the lever n alternately to ascend and descend. But the valve- 
 spindles being attached to this lever, its motion will be transferred to the valves, which will thus be 
 made alternately to ascend and descend in the same manner as when a lever is applied by manual 
 strength to the shaft S. This is the action necessary to maintain the motion of the engine, as will be 
 explained. 
 
 As in the case of the piston-rod, the parallelism of the valve-spindle is maintained by means of the 
 links o o, arranged as in the common parallel motion of stationary engines. The radius rods are at- 
 tached to opposite sides of a small framing consisting of two columns, fixed on the cover of the valve 
 casing, and having their entablature p of a semicircular form to allow the cotters of the cross-head 
 links to pass when the engine is in action. 
 
 The condenser and its appendages.— The condenser U and the lower exhaust passage T' T' are cast 
 of a piece with the sole-plate. Two strong eyes are cast in the sides of the condenser to receive the 
 main centre-shaft M', which passes completely through it. In the top is an opening for the upper 
 exhaust passage TT, the vertical part of which is cast of a piece with the hot-well X. This also rests 
 upon the condenser, but is separated from the interior by an inflected partition. 
 
 The cold water for effecting the condensation of the steam which passes into the condenser by 
 the exhaust ports, when the engine is in action, is admitted by an injection-pipe. This pipe passes 
 through the side of the vessel and communicates with the water without; but in order to regulate the 
 supply a valve is placed in the pipe, close upon the condenser; its position is marked by v in the plan 
 of the sole-plate. The face upon which the slide works is formed on the side of the condenser at v, over 
 which the casing is fixed. The mode of working the valve is by a small brass spindle which rises 
 through a packed stuffing-box in the cover of the casing; this is attached to a long lever passing to the 
 opposite side of the engine, and which can be more or less depressed at pleasure, to allow of a larger 
 or smaller supply of injection. 
 
 The part of the pipe within the condenser, passes completely across, and is perforated with numer- 
 ous small holes to diffuse the water more completely in the body of the condenser, and thereby render 
 i more effective. To prevent the water from passing into the lower exhaust, passage. a shelf is 
 
342 
 
 MARINE STEAM-ENGINE. 
 
 attached over the opening, which, throwing the water over the edge of the partition into the body of 
 the condenser, prevents it from accumulating in the passage, and at the same time renders the water o. 
 more avail than if it had been allowed to strike against the side of the condenser. 
 
 The air-pumps and valves . — The condenser communicates at bottom by a valve, called the foot- 
 valve, with the air-pump V, the barrel of which is 44 inches, clear of the sole-plate, thereby leaving 
 space for a body of water to enter it from below. The barrel of the pump is bored and lined with a 
 thin cylinder of brass turned to fit within it. A strong flange is cast round it at 11 inches from its 
 lower end, which is fitted water-tight, and bolted to the margin of a circular opening cast in the upper 
 division of the sole-plate, for the reception of the lower end of the barrel, as shown in the section, and 
 also in the plan of the sole-plate. 
 
 The bucket consists of a ring connected to the eye at the centre, into which the rod is fitted by four 
 arms. The under side of the ring has a flange cast upon it of one inch breadth, between which and 
 the projecting ledge of the junk-ring, bolted on the upper side, a packing of hemp is retained. But 
 before applying this packing, both the flange and the junk-ring are turned to work easily in the barrel. 
 The pump-rod is sheathed also with brass, to prevent corrosion by contact with the water. To apply 
 this sheathing, the rod, which consists of malleable iron, is first roughly turned ; it is then thoroughly 
 cleaned and taken to the brass foundry, where the covering of brass is cast upon it, of somewhat more 
 than the required thickness. It is again put into the lathe and turned to the requisite diameter. The 
 rod, which thus possesses all the advantages of strength and diminished liability to corrosion, is retained 
 in the tapered eye of the bucket by a cotter, and passes through a packed stuffing-box in the cover of 
 the pump. The bucket-valve is of that kind technically known as the pot-lid valve, in contradistinc- 
 tion to the butter-fly valve, which consists of two hinged flaps. The pot-lid valve consists of a circular 
 plate, which slides vertically on the pump-rod by means of a bored eye at its centre ; the plate is 
 strengthened by ribs radiating from the eye, and terminating in a narrow ring on its circumference, 
 which is faced, and fits water-tight upon the similarly faced edge of a ring projecting round the plane 
 of the bucket. 
 
 To understand the action of this valve it is only necessary to conceive the under part of the barrel 
 to be filled with water, and the bucket to be forced to descend in it ; it is then obvious that the 
 water passing between the arms will meet the under surface of the valve, and prevent it descending 
 with the bucket ; for being inelastic, and also being prevented from returning into the condenser by the 
 foot-valve, it must force a passage at the least resisting point ; but the only resistance which the 
 valve offers being its own weight, the water will bear it up and force a passage at its circumference, 
 over the ring of the bucket, and will continue to ascend relatively in the barrel so long as the bucket 
 continues to descend ; but when the bucket has attained the lowest point of the stroke and begins to 
 return, then the valve, being of greater specific gravity than the water, will shut by its own weight, 
 and will carry whatever water is above it to the height of its own ascent. The water thus carried up is 
 ejected by the valve called the discharge-valve, into the hot-well X, so called because the water thus 
 thrown into it by the air-pump, being that employed in condensation, has its temperature proportionally 
 increased. 
 
 It may be observed that the bucket and valve are of brass, as are also spindles which form their axes. 
 The box-framings of these valves are formed of cast-iron, faced with brass, and fitted water-tight into 
 their seats, where they are each retained by two long copper keys, one at each side, inserted from above 
 before the covers are put on. The covers are likewise fitted water-tight and bolted down. 
 
 The valves are prevented from opening beyond the requisite distance, by projecting bridges situated 
 before them, as shown in the section. 
 
 The hot-well . — -The hot-well, as already observed, is situated above the condenser. The part marked 
 X, with the vertical part of T, of the upper exhaust passage, is formed of a single casting, fitted water- 
 tight to the top of the condenser. In one side of the well, as shown in the section, is a rectangular 
 recess covered b/ a door, through which admission can be obtained to the interior ; and in the side ad- 
 jacent to that of the vessel, as shown in the elevation, is a circular opening to which the discharge-pipe 
 Y is bolted. Through this latter the excess of water beyond that required for supplying the boilers, is 
 discharged into the sea. The pipe consists of a single length outside of the condenser, to which it is 
 fitted by an expansion joint, to compensate for the spring of the vessel wdien at sea ; and has also a 
 valve in it capable of opening outwards, but which being shut resists the pressure of the water 
 inwards. 
 
 An air-vessel Z is placed over the hot-well and fitted to it air and water tight. The object of this 
 vessel is to create an elastic pressure by means of the air contained within it, to assist in ejecting the 
 water through the di«charge-valve should the hot-well from any cause become surcharged. The pressure 
 thus brought into action by continuing to increase with the exigency of the case will, under all ordinary 
 circumstances, prevent accumulation of water in the well to any detrimental extent. 
 
 Feed and bilge pumvs. — The same cross-head u by which the air-pump is worked, serves also to work 
 two other pumps of smaller dimensions. These are the feed-pump, by which water is supplied from 
 the hot-well to the boilers, and the bilge-pump, by which leakage water is withdrawn from the hold 
 of the vessel. These are very nearly identical in construction with the bilge-pump. The barrel is 
 formed of cast-iron, but the plunger, which is made hollow for the sake of lightness, is formed of brass. 
 It is connected to the cross-head by a cotter, a portion of the end being made solid for that purpose. 
 
 This pump communicates with the hot-well by a pipe projecting from the side of the barrel, a portion 
 of which is shown in the general elevation, where it is marked W. The feed-box is bolted upon the side 
 of the part of the hot-well formed in the condenser, at the position marked w' in the plan of the sole- 
 plate, by square flanges upon the face. In the side of the hot-well are two square holes corresponding 
 to the two openings in the feed-box, and these being made to coincide, the pipe from the feed- 
 pump is attached to the lower of the two circular openings in front of the box corresponding to the 
 lower of the square openings, and the upper communicates by a copper pipe with the boilers. This 
 
MARINE STEAM-ENGINE. 
 
 343 
 
 connection being effected, and a clack-valve, opening towards the pump, being placed in the lower 
 division of the box, and a similar valve, opening reversely, being placed in the upper division, if the 
 plunger be made to ascend in the barrel of the pump, leaving a corresponding space unoccupied, the 
 water will flow from the hot-well, by its own gravity, into the pump ; but on the plunger beginning to 
 descend the valve in that division of the feed-box will be closed by the pressure of the water tending 
 to return to the hot-well, and consequently will be forced through the upper valve, and along the feed- 
 pipe, to the boilers. But if more water be drawn by the pump than is required for the boilers, it is 
 simply ejected through the valve in the upper division of the box, and thus returned to tire well. The 
 pressure of water in the box is maintained by a loaded conical valve placed on the top : this can be 
 adjusted at pleasure to suit the pressure of steam in the boilers. 
 
 Instead of being guided by parallel-motion bars, the pump cross-head is restricted in its vertical 
 path by two guide-rods vv attached to the flanges of the feed and bilge pumps at their lower ends, and 
 to the diagonal framing above ; these pass through bushed eyes in the cross-head which is thus confined 
 at the same time that it slides freely upon the rods in its alternating ascent and descent. 
 
 The cross-head is connected to the side-levers by the rods 1 t, which are formed with solid bushed eyes 
 at their upper ends, and with butts and straps at their lower extremities. 
 
 Shifting-valve . — The bottom of the air-pump well communicates by a pipe with a small conical valve, 
 which is technically called the snifting-valve. This valve is kept shut by a screwed pin passing through 
 a malleable iron bridge made fast upon the mouth of the pipe. To the side of this pipe, above the 
 valve, is cast a small return branch, by which the water passing through the valve is carried off. 
 
 The use of this valve is to admit of the escape of the air within the condenser, air-pump, and steam- 
 passages, on starting the engine, and before these have been filled with steam. When about to start, 
 the pin is simply unscrewed by hand, to permit the valve to rise and allow the air and water to escape, 
 and give place to the steam, which now flows onwards from the valve-casing, occupying all the passages 
 and condenser, and finally begins to issue by the valve itself. 
 
 Blow-through valve. — This valve is situated at the position marked u' in the plan of the sole-plate. 
 It is placed in a chest fixed upon the steam-valve casing at the lower end, and has two openings, 
 one above and the other below the packing port. The valve itself is placed between these two 
 apertures. 
 
 This valve is used simultaneously with the snifting-valve, to allow the steam to fill the passages and 
 condenser, when preparing to start the engine, and thereby to displace the air and water which may be 
 lodged in them, through the snifting-valve. 
 
 Priming-valves. — These are two small valves, situated in the steam-ports of the cylinder, and are 
 called priming-valves from their being intended to discharge any water carried over into the cylinder 
 with the steam, and which is technically termed priming. These valves are kept shut by springs acting 
 against them externally, and of such strength as to resist the ordinary pressure of the steam ; but should 
 water lodge in the passages, owing to its non-elastic properties, it will be ejected through the valves by 
 the action of the piston tending to compress it. 
 
 Expansion geer . — The expansion geer consists of an apparatus by which the amount of steam 
 admitted during a stroke of the piston can be diminished at pleasure, when it is not required to work 
 the engines to full power. The first part of the apparatus consists of a cam with five faces fixed on 
 the crank-shaft, as shown in the elevation and plan of the engine. These faces are of different lengths, 
 giving five different degrees of expansive action. They are so formed that the friction roller on the 
 end of the lever w, and bearing against any one of them, is thrown forward through the same space ; 
 but the time of action varying as the length of the face, the effect will depend upon the particular face 
 in contact with the roller ; and this, according to its distance from the frame, may be made to bear 
 against either one or other of the faces. The position of the roller, and consequently of the lever to 
 which it is attached, is regulated by a screw and nut ; the last is formed in the back lever x, which is 
 forged of a piece with the weighted lever, and has a long hollow boss working on a stud fixed in the 
 framing. The screw has a handle upon the projecting end, which being turned causes the lever w to 
 advance or recede upon the boss of the double lever on which it slides by a sunk key. The roller is 
 kept against the face of the cam by the action of the weighted lever ; the weight tending to de- 
 scend and carry the lever with it, causes the opposite lever to press upwards against the face of 
 the cam. 
 
 The lever x is connected by a joint with an adjustable rod, carried forward to the lever y, which is 
 fast upon a cross-shaft supported by two small columns on the flange of the expansion chest, marked Gr- 
 in the elevation. On the same shaft is keyed the double-ended lever y', one end of which is connected, 
 by flexible links, with the spindle of the expansion-valve, which is of the kind known by the name of 
 equilibrium valves. The opposite end of the lever y' communicates by a rod 2 with an arrangement 
 cl levers attached to the side of the condenser, by which the apparatus can be thrown into geer and 
 disengaged at pleasure. Thus the end of the crank lever z' being moved to the right, the rod 2 will 
 be drawn down, and with it the end of the horizontal lever y' to which it is attached ; but the lever y' 
 being fast upon the same axis as the vertical lever y, this lever will be thrown back, and at the same 
 time the lever x, with which it communicates ; and again the lever x being fast upon the same axis as 
 the lever w, this last will be projected forward, and the roller thrown out of contact with the cam, and 
 the engine will receive the full supply of steam. 
 
 Action of the engine. — To bring the engine into action, the steam is allowed free admission into the 
 valve-casing by the steam-pipe G G, leading from the steam-chest over the boilers. To prevent the pipe 
 being injured by expansion, arising from the variations of temperature to which it is liable, it is pro- 
 vided with expansion-joints which allow the ends to slide upon each other, and thereby maintain the 
 same aggregate length between the two extremities. It has also a valve, called the throttle-valve, 
 placed in it to regulate the supply of steam, and to cut off the communication between the boilers and 
 the casing when necessary. The valve is placed close to the junction of the pipe with the casing; it is 
 
344 
 
 MARINE STEAM-ENGINE, 
 
 simply a disk of the same diameter as the inside of the pipe, -with a rectangular eye cast in it to receive 
 the spindle upon which it works. 
 
 The steam-ports of the cylinder being both shut by the valves, and the blow-through and snifting- 
 valves open, the steam is allowed to pass into the valve-casing by opening the throttle-valve, partially 
 at first, which fills the steam-passages and condenser, driving the air and water before it. When this 
 has been accomplished, and steam alone issues by the snifting-valve, the blow-through valve is closed, 
 and the injection-valve is opened ; the cold water now rushing into the condenser effects the conden- 
 sation of the steam with which it was filled, and creates the desired vacuum. The eccentric-rod l being 
 out of geer with the crank upon the traverse-shaft m, and a long lever, as before described, being applied 
 to the starting-shaft S, the steam-valves are raised until the under port communicates by the passage 
 with the condenser, and the upper port with the interior of the valve-casing, now full of steam, 
 which, in consequence of this disposition, will flow into the cylinder above the piston and force it to de- 
 scend. The next operation is to reverse the pressure upon the starting-lever and thereby to reverse the 
 position of the valves, shutting off the communication of the upper port with the casing, and opening it 
 to the condenser, at the same time that the communication of the lower port is cut off from the con- 
 denser and opened to the interior of the casing. This being done the steam will flow from the cylinder 
 into the condenser, and encountering there a shower of cold water from the injection-pipe, will be con- 
 densed, and a vacuum thereby formed in the cylinder above the piston. By that means the pressure 
 over the piston is removed, and the steam flowing into the cylinder beneath it, forces it to ascend to the 
 top of the cylinder. 
 
 But the piston being connected by the cross-head and side-rods, with the side-levers, carries these 
 with it in its ascent and descent, through an arc, whose chord is equal to the length of the stroke of the 
 piston ; and the side-levers being connected at their opposite ends by means of the cross-tail and con- 
 necting-rod, with the crank, the motion of the piston is thus transferred to the crank-shaft, and through 
 it to the paddles, which are fast upon its extremities. 
 
 After two or three strokes of the piston the moving parts will have acquired a certain degree of mo- 
 mentum, and this is taken advantage of to render the engine self-acting. The crank-shaft being in 
 motion, if the eccentric-rod l be thrown into geer with the traverse-shaft, exactly the same effect will be 
 produced upon the valves as by the lever applied to the starting-shaft S ; for by the alternating thrust 
 and pull of the rod, communicated to it by the eccentric R, the crank of the traverse-shaft will be made 
 1o describe a certain portion of a revolution, proportional to the eccentricity of the eccentric, and the 
 valve lever n being fast upon that shaft, the valves must consequently ascend and descend regularly 
 with the revolutions of the crank-shaft ; and these revolutions are performed uniformly with the alter- 
 nating ascent and descent of the piston. 
 
 The water is drawn out of the condenser by means of the air-pump with the same regularity ; for the 
 air-pump cross-head being worked by the side-levers, it will move simultaneously with them ; the feed- 
 pump being also attached to the same cross-head, the boilers will be furnished with water in proportion 
 to the speed of the engine, and consequently in proportion to the quantity of steam used. 
 
 Literal references. 
 
 A, the sole-plate of the engine. 
 
 a a a, holding-down bolts by which the sole-plate is 
 fixed to the keelsons. 
 
 B, the crank framing. 
 
 b b. spring-stays of the crank framing which work 
 between face-plates on the paddle-beams. 
 
 C, the diagonal framing. 
 
 cc, stay-rods connecting the framings of both en- 
 gines. 
 
 I), the parallel-motion framing. 
 
 d d , flanges by which the diagonal framing is bolted 
 to the cylinder. 
 
 E, the steam-cylinder. 
 
 F, the steam-valve casing. 
 
 G, the steam-pipe and expansion -valve chest. 
 
 H, the steam-piston rod. 
 
 I, the cylinder cross-head. 
 
 J J, the cylinder side-rods. 
 
 K K, the radius-bars of the piston-rod parallel 
 motion. 
 
 ff the radius levers of the parallel motion. 
 
 e/ g, pinching-screws for adjusting the ends of the 
 radius-bars. 
 
 L, the parallel-motion shaft. 
 
 h, the parallel-motion side-rod attached to the lever 
 f and to 
 
 M M, the great side-levers of the engine. 
 
 M', the main centre. 
 
 i i, bosses at the centres of the side-levers, through 
 which pass the keys for tightening the bearings. 
 
 X, the connecting-rod. 
 
 0, the cross-tail of the connecting-rod. 
 
 j, the cross-tail links. 
 
 P P, the cranks. 
 
 Q Q, the crank or paddle shaft. 
 
 R, the eccentric for working the valves. 
 
 l, the eccentric-rod. 
 
 m, the traverse or valve shaft. 
 
 n, the valve-lever. 
 
 o, small parallel-motion for the valve-spindle. 
 
 p, a small framing to which are attached the 
 ends of the radius-bars of the valve parallel- 
 motion. 
 
 q, the back balance or counter weight of the 
 valve. 
 
 r, the back balance or counter weight of the ec- 
 centric. 
 
 s s, levers by which the valve counter weight is 
 attached to 
 
 S, the starting-shaft. 
 
 T and T', the upper and lower exhaust passages. 
 
 U, the condenser, cast of a piece with the sole-plate. 
 
 V, the air-pump cylinder, lined with brass. 
 
 1 1, the air-pump side-rods. 
 
 u, the air-pump cross-head. 
 
 v, guides for the air-pump cross-head. 
 
 W, the feed-pump. 
 
 X, the hot-well. 
 
 Y, the discharge-pipe. 
 
 Z, the air-vessel. 
 
 u’, (in plan of sole-plate) the part of the sole-plate 
 to which the blow-through valve is bolted. 
 v', (in plan of sole-plate) a projection on the conden- 
 ser, to which the expansion-valve casing is bolted 
 

 
 
MARINE STEAM-ENGINE. 
 
 345 
 
 •o', (in plan of sole-plate) the part of the hot-well 
 to which the feed-chest is bolted. 
 w, the movable lever of the expansion-geer. 
 
 x, the fixed lever of the expansion-geer. 
 y y' y\ additional levers for working the expansion- 
 valve. 
 
 American Marine Steam-Engine . — Section and details of the engine of the United States Mail 
 Steamer Pacific, built at the Aliaire Works city of New York, after the design of C. W. Copeland, Esq 
 
 Details. 
 
 Fig. 2717, longitudinal section of engine. 
 
 Fig. 2718 shows a plan of the bed plate. 
 
 Fig. 2719, a longitudinal projection. 
 
 Fig. 2720, a transverse section, vertically of the 
 bed-plate and condenser through the centre of 
 the side-lever shaft bearing. 
 
 Fig. 2721, transverse section of bed-plate through 
 the centre of the sockets, for the support of the 
 pillow-block columns. 
 
 Fig. 2722 shows a vertical elevation of steam cyl- 
 inder. 
 
 Fig. 2723, plan. 
 
 Fig. 2724, a vertical elevation of the air-pump. 
 
 Fig. 2725, plan. 
 
 Fig. 2726 shows a longitudinal projection of side- 
 lever. 
 
 Fig. 2727, plan. 
 
 Fig. 2728, a vertical section through steam piston. 
 Fig. 2729, sectional plan. 
 
 Fig. 2730, side elevation of outboard pillow-blocks. 
 Fig. 2731, plan. 
 
 Fig. 2732, plan of reservoir. 
 
 Fig. 2733, end projection. 
 
 Fig. 2734, side elevation. 
 
 Fig. 2735, vertical section through man-hole open- 
 ing- 
 
 Fig. 2736, longitudinal projection of main pillow- 
 block. 
 
 Fig. 2737, plan. 
 
 Fig. 2738, section through socket for column. 
 
 Fig. 2739, vertical projection of air column. 
 
 Fig. 2740, plan. 
 
 Fig. 2741, front view of upper steam-chest. 
 
 Fig. 2742, end view of upper steam-chest. 
 
 Fig. 2743, front view of lower steam-chest, with 
 side-pipes attached to upper chest. 
 
 Fig. 2744, end view of lower steam-chests. 
 
 Fig. 2745, vertical section through air-pump cover. 
 Fig. 2746, plan. 
 
 Fig. 2747, vertical section through air-pump bucket 
 and valve. 
 
 Fig. 2748, plan. 
 
 Fig. 2749, vertical section of cylinder top and false 
 cover. 
 
 Fig. 2750, plan. 
 
 Fig. 2751, side view of cut-off eccentric. 
 
 Fig. 2752, end view. 
 
 Fig. 2753,. side view of steam eccentric. 
 
 Fig. 2754, end view. 
 
 Fig. 2755, vertical elevation of force-pump. 
 
 Fig. 2756, vertical section. 
 
 Fig. 2757, plan. 
 
 Fig. 2758, vertical elevation of bilge-pump. 
 
 Fig. 2759, plan. 
 
 Fig. 2760, elevation of force-pump plunger. 
 
 Fig. 2761, side projection of force-pump chest. 
 
 Fig. 2762, plan. 
 
 Fig. 2763, front view of bonnet to close over opening 
 to adjust valves. 
 
 Fig. 2764, end view. 
 
 Fig. 2765 plan of bilge-pump chest. 
 
 Fig. 2766, longitudinal projection. 
 
 Fig. 2767, end elevation. 
 
 Fig. 2768, plan of bonnet. 
 
 Fig. 2769, end view of bonnet. 
 
 Fig. 2770, plan of bilge-pump plunger. 
 
 Fig. 2771, vertical section. 
 
 Fig. 2772, side view of centre-bearing for water- 
 wheel shaft. 
 
 Fig. 2773, plan. 
 
 Fig. 2774, water-wheel shaft. 
 
 Fig. 2775, centre water-wheel shaft. 
 
 Fig. 2776, side view of driven crank. 
 
 Fig. 2777, plan. 
 
 Fig. 2778, side view of driving-crank. 
 
 Fig. 2779, plan. 
 
 Fig. 2780, parallel-motion shaft. 
 
 Fig. 2781, end view of parallel-motion arm. 
 
 Fig. 2782, plan. 
 
 Fig. 2783, side view and plan of air-pump rods. 
 Fig. 2784, side view and plan of radius rods for 
 parallel motion. 
 
 Fig. 2785, side view and plan of parallel-motion 
 connecting-rod. 
 
 Fig. 2786, pillow-block columns. 
 
 Fig. 2787, side elevation of bush for driven crank. 
 Fig. 2788, plan. 
 
 Fig. 2789, vertical elevation of cross-tail, with side- 
 lever links attached. 
 
 Fig. 2790, plan of cross-tail. 
 
 Fig. 2791, end view of side-lever links. 
 
 Fig. 2792, plan. 
 
 Fig. 2793, vertical projection of cylinder cross-head. 
 Fig. 2794, plan. 
 
 Fig. 2795, piston-rod. 
 
 Fig. 2796, side view of side-lever shaft, with washers 
 on the ends. 
 
 Fig. 2797, end view. 
 
 Fig. 2798, side view and plan of main connecting- 
 rod. 
 
 Fig. 2799, side view and plan of cylinder side- 
 links. 
 
 Fig. 2800, side view and plan of cut-off eccentric- 
 rod. 
 
 Fig. 2801, side view and plan of steam eccentric- 
 rod. 
 
 Fig. 2802, vertical elevation of air-pump cross-head. 
 Fig. 2803, plan. 
 
 Literal References to Fig. 2717. 
 
 A, the bed-plate, upon which the engine stands. 
 
 B, the cylinder bottom, cast upon the bed-plate, in 
 which is the lower steam opening. 
 
 C, cylinder. 
 
 D, steam piston. 
 
 E, piston-rod. 
 
 F, cylinder cross-head, attached to the piston-rod, 
 and also to the side levers, by two side-rods. 
 
 G, cylinder side-rods. 
 
 H H, upper and lower steam-chests, in which are 
 fitted valves for the induction and eduction of 
 steam to and from the cylinder. 
 
346 
 
 MARINE STEAM-ENGINE. 
 
 1 1, steam-valves. 
 
 J J, valve-stems, on which are keyed the steam- 
 valves. 
 
 K, parallel-motion shaft and standard. 
 
 L, lifting-rods, for lifting steam and exhaust valves, 
 worked from an eccentric on the water-wheel 
 shaft. 
 
 M it, steam-toes, keyed to the lifting-rod. 
 
 N N, feet for lifting -rod, attached to the rock- 
 shaft. 
 
 O, steam and exhaust side-pipes. 
 
 P, foot-valves and seats. 
 
 Q, condenser, cast upon bed-plate. 
 
 R, side-lever shaft, passing through and firmly keyed 
 to condenser. 
 
 e e, pillow-block columns, keyed into sockets cast 
 upon the bed-plate. 
 
 /, pillow-blocks for water-wheel shafts. 
 
 g, cranks. 
 
 h, main connecting-rod, connecting cross-tail and 
 crank-pin. 
 
 i, cross-tail, attached to the side-levers by two 
 short links, also the main connecting-rod. 
 
 j, main-braces from pillow-blocks to cylinder. 
 
 k, steam-valve lifters, keyed to the lifting-rods. 
 
 l, parallel bar for parallel motion. 
 
 m, parallel motion connecting-rod 
 
 n, eccentric-rod. 
 
 o, guide-rod for air-pump cross-head. 
 
 p, brace from pillow blocks to bed-plate. 
 
 S, side-levers. 
 
 T, hot-well. 
 
 U, injection-pipe. 
 
 V, connection, from exhaust-pipe to condenser. 
 
 W, air-column, to receive the air arising from the 
 waste water, thereby facilitating its discharge. 
 
 X, air-pump. 
 
 Y, air-pump piston. 
 
 Z, air-pump rod. 
 
 a, air-pump cross-head. 
 
 b, delivery valves and seats. 
 d, force-pump chest. 
 
 q, injection-valve. 
 
 r, centre-bearing for rock-shaft. 
 
 s, brace from cylinder to bed-plate. 
 
 1 t, cross-beams for pillow-blocks. 
 
 u u, studs and transverse braces. 
 
 v, nuts for securing pillow-blocks to columns. 
 
 w, bolts for holding down pillow-block caps. 
 
 I x Xy studs between columns and bolts, running trans- 
 j versely through each set. 
 y, braces from pillow-blocks to bed-plates, in the 
 centre of each and between engines. 
 
 Zy snifting-valve. 
 
 I ’ ° 
 
MARINE STEAM-ENGINE. 
 
 34? 
 
 2 ? 21 . 
 
348 
 
 MARINE STEAM-ENGINE. 
 
MARINE STEAM-ENGINE. 
 
 341 ) 
 
350 
 
 MARINE STEAM-ENGINE. 
 
5J77II. 
 
 MARINE STEAM-ENGINE. 
 
 351 
 
 0 
 
 01 
 
 F'PM ' ii rq 
 
 CO 
 G 1 
 
 Cl 
 
 l^ffj 
 
352 
 
 MARINE STEAM-ENGINE. 
 
 urn 
 

 
 
 
 
 


 fLJIIL 
 

 
 
 
 
 
 
 » 
 
 
 
 
2794 
 
 MARINE STEAM-ENGINE. 
 
 35S 
 
 w "i t 1 ; ; i 
 
 Yol. II. — 23 
 
354 
 
 MARINE STEAM ENGINE. 
 
 Engines of the Golden Gate. Plate II. is the front elevation, and Plate III. the side elevation an« 
 section through air pumps, a main shaft, b crank-pin, cccc cylinder; d trunnions on which the 
 cylinder oscillates to accommodate itself to the motion of the crank ; e stuffing box on the cylin- 
 der-head. This is made as long as practicable, to give as much bearing as possible for oscillating 
 the cylinder, f f belt-passage connecting the trunnion with gg side-pipe, hli valve-stems, connect- 
 ing with the balance puppet-valves in Hi valve-chests. The lower valve on the right or steam side 
 is concealed by j j j j, air-pump; the air-pump bucket is provided with India-rubber valves, and is 
 worked by k, crank on the intermediate shaft. I III, condenser : there are two condensers and two air- 
 pumps ; they are located between the cylinders and inclined towards each other, one only being repre- 
 sented. 
 
 The passage f f, together with the side-pipes, valve-chests, and appurtenances, are fixed to the cylin- 
 der, and oscillate with it, the steam being received through one trunnion and allowed to escape to the 
 condenser through the opposite one. m is an injection-cock admitting the water upon a scattering plate 
 in the condenser. These are the first oscillating engines to which balance puppet-valves have ever been 
 applied ; and the constructors, Messrs. Stillman & Allen, deserve great credit for successfully carrying 
 out so decided an improvement. 
 
 The valves are worked by the toes o o in the usual manner. The rock-shafts p p receive motion partly 
 from the movement of the cylinder, and partly from the eccentric. Levers are permanently attached to 
 the trip-shafts qq, the ends of which work in a slotted piece curved to the centre of the trunnion. This 
 piece is guided, as represented in the engraving, by vertical rods sliding in bushes attached to the fixed 
 framing, and is connected by a rod to the starting lever r, all the levers for working by hand being so 
 balanced, that the engineer with one hand can work the engine up to the usual speed. The cut-off 
 valve is placed outside the trunnion, and is a balance puppet-valve, worked by the ordinary cam motion, 
 and so arranged as to act either as cut-off or throttle, or both, the levers being placed within reach of 
 the engineer when working the engine. 
 
 The Golden Gate has four return tubular boilers — two forward and two aft of the engines. They are 
 placed at the sides of the ship, leaving room for the fire-room in the centre. The furnaces are conse- 
 quently athwart-ships instead of ranging fore and aft as usual. 
 
 The Illeiois, plying between this city and Chagres, the John L. Stevens, the Augusta, plying between 
 this city and Savannah, the Republic, the Agnes, a vessel constructed for the Spanish government in 
 1850, the Arago of the Havre line, the Adriatic of the Collins line, are among the American examples 
 of paddle-wheel steamers fitted with oscillating engines. 
 
 The Golden Gate is of the following principal dimensions : Length on deck, 265 feet ; beam, 40 feet ; 
 depth of hold, 22 feet; tonnage, 2030 tons; diameter of cylinders, 85 inches; stroke, 9 feet; average 
 revolutions, 18^; average pressure in boilers above atmosphere, 12 lbs. ; cut-off from commencement, 3 
 feet ; amount of fire surface, 1 2,052 square feet ; tube surface, 8396 ; grate surface, 367 ; calorimeter 
 of tubes, 61f feet; paddle-wheels, diameter 31 feet; length of paddle, 12 feet; depth, 24 inches; num- 
 ber of paddles in each wheel, 30. 
 
 Sorrows ’ Double Acting Reversible Rotary Steam Engine. — Arranged for working steam expansively. 
 
 Plate IV. is a perspective view of two cylinders or engines fixed on one shaft for the expansive work- 
 ing of the steam. The cylinders are of equal diameter but of unequal length. The steam^s first ad- 
 mitted to the smaller; after doing its work in which, the greater part is admitted at a lower pressure to 
 the larger cylinder. In this respect, working the steam through two engines, it somewhat resembles the 
 well-known Woolf engine, but with this difference, that the steam is taken from the first engine at such 
 a point that it exerts no back pressure. This will be understood by examining Plate V., which repre- 
 sents a vertical and horizontal section of the smaller engine only. The larger engine resembles this, 
 except in having but four instead of eight pistons, or leaves, and in having no outlets for the steam at 
 the top and bottom, as in the smaller. 
 
 c is a pedestal of cast iron on which the cylinder rests, forming the whole of the frame of the engine ; 
 a is the cylinder, whose inner periphery is turned perfectly true, and whose ends are closed by heads d d, 
 in each of widen heads is a groove h h, the form of which is best shown in fig. 5 by dotted lines, 
 being that of a circle with segments cut off on opposite sides, leaving only two-fourths of its circum- 
 ference. On opposite sides of the cylinder are abutments n n , cast upon the steam-heads m m ; on either 
 side of which abutments are quadrangular openings 1 1', u v! , connecting with the double three-way cocks 
 qq. To the inside of the cylinder is fitted the steam- wheel ee ee e'e'. The ends of the steam-wheel are 
 formed of two plates ee, ee, of a diameter equal to the interior of the cylinder, and secured by bolts ii, 
 to a ring e'e' of less diameter, which forms the bottom of the channel f, in which the steam acts. Its 
 axle j passes through boxes in the cylinder ends, packed with metallic packing, and lined with anti- 
 friction rollers. The rollers may, no doubt, be omitted in practice, as a refinement of little use, if not 
 positively productive of derangement. The peripheries of the two plates ee, ee, forming the ends of the 
 steam-wheel, are made to fit steam-tight to the interior of the cylinder, by means of metallic packing- 
 rings let into the interior of their flanges as represented. The abutments n n are packed with metallic 
 packing o to the bottom, and p to the sides of the channel/'; the packing-pieces o and p being dove- 
 tailed together, so that p will slide with o, but at the same time slide outwards, independently of it as they 
 wear. The steam acts in the passage f upon 8 slides or leaves g g, which we will term pistons, which 
 revolve with the steam-wheel, but are capable of sliding to or from the centre through slots in the ring 
 ee. It will be seen that the sides of the channel f are formed by the plates ee, before described, so 
 that the channel is, in fact, wholly sunk in the rim of the steam-wheel. The pistons are made a little 
 wider than ‘-he channel, and partially supported by shallow radial grooves on the inside of the plates 
 ee. The p' it ms are packed on their edges both to the inner periphery of the cylinder and to the grooves 
 «i the sides of the channel/'. This packing is shown on the right hand of fig. 2, Plate V., in section, the 
 section being taken through the centre of the piston, and exhibiting the end and side packing dovetailed 
 
MARINE STEAM ENGINE. 
 
 355 
 
 loosely together in the same manner as already described in the packing of the abutments. The slots 
 through which the piston slides are also packed, as represented in fig. 1. All the packing pieces are 
 kept to their work by small helical springs at their hacks. From the inner edge of each piston at each 
 side, a square stud V projects through a radial slot f ', in the plates ee, and at the end of each stud is a 
 pivot </, carrying a friction-roller. These friction-rollers travel in the grooves h h, inside the fixed cyl- 
 inder head, and during the revolution of the wheel cause the pistons to alternately project and with- 
 draw into the wheel. By the form of the groove, it will be seen that each piston will project across the 
 channel f during two-fourths of the revolution, while during the remaining two-fourths, it will be wholly 
 or in part withdrawn into the interior of the wheel. At the moment of passing either abutment re re, 
 the outer edge of the piston will coincide with the outer surface of the ring e'e', so that the packing 
 pieces oo of the abutments have presented to them by the revolution of the steam-wheel simply a con- 
 tinuous cylindrical surface. 
 
 The steam-heads or cocks m m, through which the steam is admitted to the cylinder, and which 
 supply the place of valves, valve-gear, and reversing-gear in ordinary engines, are of peculiar con- 
 struction, having six ways or passages in each. There are conical seats in each to receive the plugs 
 q q', in which are passages to correspond with the ways in the steam-heads. The steam-pipe s 
 has two branches leading to the two steam-heads. Of the six ways or passages in each steam-head, 
 two 1 1' are steam-passages leading from the cock-seats into the channel f the former above and the 
 latter below the abutment, (see the right-hand side of fig. 1, Plate V.) ; re re' are exhaust passages leading 
 from the cylinder to the cock-seats, the former from above and the latter from below the abutments 
 (see left-hand side of fig. 1, Plate V.). In addition to the four already described, one r leads from the steam- 
 pipe to the cock-seat, and the remaining one v, fig. 2, Plate V. is a continuation of the cock-seat, provided 
 with a flange at its extremity for connecting to the exhaust-pipe. The vertical section, fig. 1, is taken 
 through the steam-passages on the right side, but through the exhaust-passages on the left. The plugs 
 q q' have each two passages, the first k, fig. 2, being for the purpose of communication between the 
 steam-pipe and either of the passages 1 1', and admitting steam on either the upper or lower side of its 
 corresponding abutment, the other l, in a hollow part of the plug, being for forming a communication 
 between the exhaust-passage v, and the opposite side of the abutment to that which is in communica- 
 tion with the steam-pipe. The two plugs q q' are furnished with levers (see Plate IV.), by which they are 
 turned to admit the steam on either side of the abutment, and allow the escape of the exhaust from the 
 opposite side, and the levers are connected, so that both are reversed at the same instant. Whatever re- 
 lation, therefore, exists between the several passages in one steam-head and cock, the opposite relation 
 must exist between the passages in the other. In fig. 1, Plate V., the cock on the right-hand side of the fig- 
 ure is in such position, that steam is admitted through the passage t above the abutment, the passage t' 
 being effectually closed, while in the same cock the exhaust passage u', imperfectly represented by dotted 
 lines as being more distant from the eye, is open, and admits the exhaust steam to escape from the lower 
 side of the abutment into the hollow portion of the plug at its further end. In the other steam-head, 
 the lower steam and the upper exhaust are supposed to be open, the dotted steam-passages 1 1 1 being o~ 
 this side nearer the eye than the exhaust passages re re', through which this section is taken. 
 
 It will be recollected that there is no movement of these cocks, except in reversing, all the passages 
 being full open, and the steam exerting its full force in every possible position of the wheel. The arrows 
 indicate the movements of the steam, and also the direction in which tire wheel revolves, every particle 
 of steam expended being effective in driving the wheel, without loss by filling any cavities uselessly, as 
 in the valve passages and clearance of every variety of reciprocating engine. 
 
 It now remains to describe the provision for rendering available some portion of the expansive power 
 of the steam. The spaces in the channel f between each piston appear as if filled with steam of full pres- 
 sure, which is carried along by the revolution of the wheel, and discharged into the exhaust passage of the 
 opposite steam-head. This would be the case but for the passages w w', midway between the steam- 
 heads, through which a large portion of the steam thus confined expands itself into the second or mate 
 engine, which is of similar construction, but containing only four instead of eight pistons. The channel 
 in which the steam works in the second engine may also be deeper, and any desired ratio may subsist 
 between the capacities of the two engines. Suppose the boiler pressure to be 60 lbs. per square inch, 
 and the capacity of the second engine be twice that of the first, steam from the boiler at 60 lbs. above the 
 atmosphere, or 75 lbs. total pressure, is expanded in passing the passage w into three times its original 
 space, two volumes going over into the second engine, while one volume remains in the first. The pres- 
 sure will thus be reduced, according to the law of Boyle and Marriotte, to about t 5 = 25 lbs. total, or 
 10 lbs. above the atmosphere. The additional force, therefore, due to the existence of the second en- 
 gine will be that of 10 lbs. per inch upon a double area, or one-third that of the first engine [10 x 2 
 = 60 x •$■]. If the engines are condensing, and exhaust into a perfect vacuum, the power of the second 
 engine will be two-thirds that of the first [25 x 2 =75 x £]. If the second engine be only equal in ca- 
 cacity to the first, the pressure on its pistons will be half the boiler pressure, or 37-5 lbs. ; and the effect 
 of the second will be one-half the first, when both exhaust into a vacuum, or a little more than one- 
 third when exhausting into the atmosphere [37'5 — 15 = 22'5 lbs. 22-5 > 60 x $■]. Any one may read- 
 ily calculate the effect of any other ratio between the cylinders, or of any other initial pressure than 00 
 lbs. The inventor prefers a second cylinder of about twice the capacity of' the first. 
 
 A considerable advantage to be derived under some circumstances from the existence of two engines, 
 is the possibility of using both for a few minutes on any extraordinary occasion, under full pressure, by 
 connecting each directly with the boiler. In Plate IV., a represents the first and b the second engine. 
 Under ordinary circumstances, the stop-valves c and d being open, the steam from the boiler would be 
 admitted through e into a alone, after working through which, a portion would pass over through the 
 stop-valve d into the cylinder b. Should occasion require an extraordinary effort, the valve d may be 
 closed and e opened, thus shutting the communication between the engines, and opening each to the full 
 
356 
 
 MARINE STEAM ENGINE. 
 
 pressure of steam from the boiler. Both might be thus worked so long as the boiler could generate a 
 sufficient supply of steam. 
 
 Compound Engines of the Steamship Thorwaldsen (Plate VI.), constructed by Messrs. Oswald & 
 Co., of Sunderland, Eng. The engines are of the overhead cylinder type with an intermediate receiver, 
 the cylinders — not steam jacketed — 51" and 86" in diam., with a stroke of 3 ft. 6”. The inter- 
 mediate receiver surrounds the high-pressure cylinder, and is of the same capacity. The valve-chest 
 of the high-pressure cylinder is situated at the forward end of the engines, that for the low-pressure 
 cylinder between the cylinders. The valves of both cylinders are double-ported, that for the high- 
 pressure cylinder being equilibrated by a ring at the back. 
 
 High-pressure cylinder. 
 
 Feet. Inches. 
 
 Low-pressure cylinder. 
 
 Feet. Inches. 
 
 Length of ports, 
 
 . 2 
 
 6 
 
 Length of ports, . 
 
 . 5 
 
 0 
 
 Width of steam ports, 
 
 . 0 
 
 3» L 
 
 Width of steam ports, 
 
 . 0 
 
 
 “ exhaust ports, 
 
 .- 0 
 
 9 
 
 “ exhaust ports, 
 
 . 0 
 
 91 
 
 The maximum travel of the valves is in each case 8", and each of the valves has its weight counter- 
 balanced by the pressure of the steam acting on an 8-inch piston working in a balance cylinder. 
 
 Besides the stroke of main valves being adjustable by means of the link motion, the high-pressure 
 cylinder is fitted with a separate expansion-slide which works on a face at the side of the main valve 
 chest, and which has an adjustable travel. Eor starting the engines, or moving them by hand, small 
 supplementary slide-valves are provided, at the front of the cylinders, moved by hand-levers. By 
 means of one of these slides steam can be admitted direct to the low-pressure cylinder. 
 
 Between the exhaust-pipe and the low-pressure cylinder a chamber is interposed, fitted with an 
 injection-pipe, to form a feed-heater by which the temperature of the feed is raised to about 160°. 
 
 The circulating pump is driven by a prolongation upward of the air-pump rod, both pumps being 
 actuated by back levers connected to the crosshead of the low-pressure cylinder. To the air-pump 
 crosshead are also connected the feed and bilge pumps, these pumps having 6^-incli plungers, and 
 stroke 1 ft. 9". The air-pump is single-acting, and has a diameter of 36". 
 
 The piston-rods are each 8" diam. below the piston, and they are continued upward, working 
 through stuffing-boxes in the top cylinder-covers. The crosshead gudgeons are 10J-" in diameter by 
 11" long, and the guide-blocks are 15" wide by 2 ft. 5" long. The connecting-rods are 7 ft. 9" long, 
 and the crank-pins have bearings 13|" long by 13^-" diam. The diameter of the crank-shaft is 13^-" 
 throughout, with 4 bearings, and each 18 inches long. 
 
 The thrust bearing has 9 collars placed l£" apart, these collars being each thick and 15" diam. 
 outside. The diameter between the collars is 12". The intermediate shafting is 12" in diam., with 
 bearings of the same diameter, and 12' long, while the propeller shaft is 12J" diam., and the lignum- 
 vitm bearings are 14j" diam., and 2 ft. 7" and 3 ft. 10" long respectively. 
 
 The propeller is 16 ft. 6” in diameter, and from 18 feet to 22 feet pitch. The boss is 4 feet in 
 diameter, and it has four arms, each with an area of 14 square feet. 
 
 The engines are supplied with steam by four boilers, each 12 ft 3" diam. by 10 ft. 6" long. Each 
 boiler contains three furnaces, each 3 feet in diameter. The grates are 6 ft. 6" long. The boiler- 
 tubes are of brass and are 3§" diam. by 7 ft. long. The chimney is 8 ft. in diameter, and the safety- 
 valves, which are eight in number, have each a diameter of 4j". The main steam-pipe is 13", the 
 waste steam-pipe 114”. The main feed and bilge pipes are 4j inches in diameter. 
 
 Marine Engines , by Mr. J. Hall, Munich, for the tipper Danube. Fig. 2804 is a side elevation of one 
 of the engines, with boiler and paddle-wheel, as fitted in the vessel. Fig. 2805 is a corresponding trans- 
 verse section through the vessel, showing both engines, with various parts in section. The view oi: 
 the right of the centre line represents sections through the paddle-box, air-pump, feed-pump, crank shaft 
 journals, condenser passage, and the barrel of the boiler — the cylinders not being shown. On the left, 
 the air-pump and paddle-wheel are in elevation, the cylinder being in section through its exhaust passage, 
 as in connection with the blast-pipe. Figure 2806 is a plan of the combined engines, one being in hori- 
 zontal section. The boiler and the fire-box A B, are constructed just as in a locomotive. At C C are 
 two parallel frames of double boiler plate, filled in with timber, running along the boiler, and riveted 
 fast to it. D D are t-wo similar frames, standing up from the bottom of the boat ; and these four lines 
 of framing carry, at one end, the four inner journals of the paddle-shaft, and at the other the pair of 
 steam cylinders E E. The steam is admitted in the usual way by a regulator in the dome, through the 
 pipe F, to the steam-chest G. The expansion-vale spindle H, has a right and left-hand screw at 1 1, 
 each screw having a plain cut-off slide, commanding the steam ports J, leading into the second steam- 
 chest K, and fitted with piston-valves worked by the spindle L The cut-off spindle H, is worked by 
 the outside eccentric M, the rod of which is linked to it direct. The variation in the expansion is ef- 
 fected by the light shaft N, passing alongside the engines to the engineer’s hand, and having a bevel 
 pinion O, gearing with a similar pinion P, on the transverse shaft Q, passing across between both en- 
 gines. In this way the shaft N, commands the valves of both engines through the two pairs of bevel 
 pinions B R — the result of turning the shaft N to the right or left being to expand or approximate the 
 two cut-off-slides by the right and left screws, and thus increase or diminish the degree of expansion 
 without affecting the lead. The cylindrical, or piston-valve chest, has three valves S T and U, on the 
 same rod V ; and, as represented in the horizontal section, the engine is upon its bottom centre, and 
 steam is entering between the valves U and T ; the valve U being on the point of opening to admit 
 steam to the cylinder — the waste steam of the previous stroke having escaped by the opening cast in 
 the middle of the cylinder, and through similar recesses formed in the valve T, into the blast-pipe W. 
 Mow it is to be remembered that the valve U must travel downwards until its port leading into the cyl* 
 

 
 
 
 
 
 
 
 
 
 
 
 
MARINE STEAM ENGINE. 
 
 357 
 
 inder is full open ; and, as the whole three valves are on one rod, as U is opening to admit steam to the 
 cylinder, T is closing the communication between the cylinder and the blast-pipe. So soon as the ports’ 
 
 1 
 
 i 
 
 =P 
 
 5 
 
 H 
 
 
 to the blast-pipe — which are only half the width of the valve — are closed, the other valve S opens, and 
 the remaining vapor escapes through the pipes X, cast on the steam-chest, to the pipe Y, leading to the 
 condenser Z. As the expansion at each stroke commences at the face of the cut-off slides, whatever 
 amount of steam may be in the piston-valve chest at the time is also expanded; therefore, to diminish 
 this amount as much as possible, two additional pistons S' S', are fitted upon the valve-rod, for the pur- 
 
 pose of displacing the steam which would otherwise collect at each stroke in the valve-chest.. The air- 
 pump a, is of the ordinary construction : it is bolted on to the condenser, and is worked by the same ec- 
 centric which works the expansion valves. The piston steam-slides, S T and U, are worked by the back 
 and forward eccentrics b b, through the reversing link c. The backward eccentric also works the feed- 
 pump d — the feed being taken from the hot well, whilst the remainder runs to waste by the pipe e. 
 
 The steam is admitted to the cylinder when the piston is on the centre, and is allowed to escape tc 
 
358 
 
 MARINE STEAM ENGINE. 
 
 the eduction-port or blast-pipe when the piston is lfths inch from the end of its stroke. The valve S 
 opens to the condenser when the piston has travelled lfths inch from the commencement of its stroka 
 — the full length of stroke being 30 inches — so that the cylinder is open to the condenser when the pu 
 
 At jf and g, two cocks are placed upon the pipe Y, leading to the condenser, and these cocks are so 
 arranged that when one is open the other is shut. The injection-pipe h, is placed between the air- 
 pump°and the cocks f and g, so that by reversing the latter by means of the rods and levers k k , the en- 
 gine will work with the condenser or without it. When working without the condenser, the cylinder is 
 open to the atmosphere throughout the entire stroke, as in the common high-pressure engine, and under 
 such circumstances, the pipe l is open to the feed-pump, for the boiler supply. The pipe m, leads to a 
 small steam pump not seen in the drawing, and the pipe n , conveys the water from the steam pump to 
 the boiler. The pipe o is the blow-off pipe. 
 

 
PL.m. 
 

 
 
MATCHES. 
 
 359 
 
 MATCHES. The contrivances in which sulphur matches were inflamed by immersion in phospho- 
 rus (phosphorous matches) were first superseded by the so-called chemical matches, which consisted of 
 sulphur matches, with a coating of chlorate of potash. This salt, when brought into contact with con- 
 centrated sulphuric acid in the cold, is decomposed with explosion and the production of fire, into bisul- 
 phate of potash, perchlorate of potash, and chlorous acid, and by the two latter (one of which is re 
 solved into chlorine and oxygen, and the other into chloride of potassium and oxygen) inflammable 
 matters of all kinds, as sulphur, metallic sulphurets, resin, gum, &c., are inflamed, when within the im- 
 r icdiate reach of its action. The sulphur ends of the matches are covered with a composition of chlo- 
 rate of potash, flowers of sulphur, colophony, gum, and cinnabar, (as a coloring matter:) on dipping 
 this into a bottle containing asbestus, previously moistened with sulphuric acid, it quickly becomes in- 
 flamed. These matches are now superseded by the more simple lueifer matches, which inflame with- 
 out the aid of acid, or any thing of the kind, by mere friction ; an invention, the history of which, not- 
 withstanding its novelty, is already lost, partly on account of its simplicity, and from the rapid intro- 
 duction of similar processes. 
 
 Lucifer matches . — These, like the last, are sulphur matches, to which a separate inflammable com- 
 pound has been added. The primary coating of sulphur cannot be dispensed with, because the 
 inflammable composition burns much too rapidly to set fire to the wood. The flame produced by the 
 combustible mixture is, therefore, first communicated to the sulphur, and from it to the wood. Thu 
 mixture at first contained chlorate of potash as an essential ingredient, and the production of fire de 
 pended upon the power of this substance of inflaming the sulphur, phosphorus, &c., with explosion, the 
 effect being produced even by shaking or friction. Thus phosphorus was mixed with mucilage, at a 
 temperature of 104° F., so as to form an emulsion, to which the chlorate of potash was then added. 
 The phosphorus was sometimes replaced by sulphuret of antimony. The operation of mixing the in- 
 gredients in the dry state is at all times dangerous. The unpleasant noise which occurred whenever a 
 match was inflamed, and a certain amount of danger from fire, rendered it desirable to replace the de- 
 tonating action of the mixture by a slow combustion, and this has been accomplished in the noiseless 
 lueifer matches. None of those compositions which inflame without explosion contain chlorate of pot- 
 ash, but nitre and phosphorus instead ; the latter of which burns at the expense of the oxygen of the 
 former. The general principle concerned in the action of these matches is, that substances (as phos- 
 phorus) having a great affinity for oxygen, are mixed with a large amount of it, condensed into a small 
 space, (in the nitre,) so that the slightest cause is sufficient to effect their combination. The peroxides 
 of lead and manganese, which abound in oxygen, are often mixed with the nitre ; they act in the same 
 way when they have once attained a red heat. 
 
 As the thickness of the match, and the quantity of the composition upon it, must always bear a cer- 
 tain proportion, both because the latter is expensive, and burns with a disagreeable odor, the matche ■: 
 require to be cut by machinery, or planes constructed for the purpose ; they are thus obtained thin, suf- 
 ficiently strong, perfectly uniform, and of an elegant appearance. Moist poplar w'ood is best suited for 
 this purpose. The round or angular matches are dipped in bundles into melted sulphur, and then 
 coated with the inflammable composition : sixteen parts of gum-arabic, 9 parts of phosphorus, 14 parts 
 of nitre, and 16 of finely divided peroxide of manganese, form a good composition, which must be 
 worked up with water to avoid danger. The mixture then forms a thick paste, into which the matches 
 are separately dipped and then dried. Occasionally, smalt and similar matters are added, to produce 
 certain colors, or to increase the effects of friction. After repeated trials, the inflammability of the 
 composition has been gradually diminished to such an extent, that it only inflames when strongly 
 rubbed against rough surfaces, but not readily by pressure or shaking, especially when the matches are 
 preserved in closed boxes ; hence they are much less dangerous than might be anticipated. The slow 
 combustion of the sulphur, with the emission of sulphurous acid, forms a great objection to these 
 matches, as this gas is injurious to respiration. Matches have consequently been introduced into com- 
 merce which have been first dipped into fused stearine, instead of sulphur ; these, however, frequently 
 miss fire. 
 
 According to Ure, the following process answers well : 
 
 Phosphorus 4 parts. 
 
 Nitre 10 “ 
 
 Fine glue 6 “ 
 
 Red ochre, or red lead 5 “ 
 
 Smalt 2 “ 
 
 Convert the glue, with a little water, by a gentle heat, into a smooth jelly ; put it into a slightly warm 
 porcelain mortar to liquify ; run the phosphorus down through this gelatine at a temperature of about 
 140° or 150° F. ; add the nitre, then the red powder, and lastly the smalt, till the whole forms a uni- 
 form paste. To make writing-paper matches, which burn with a bright flame, and diffuse an agreeable 
 odor, moisten each side of the paper with tincture of benzoin, dry it, cut it into slips, and smear one oi 
 their ends with a little of the above paste by means of a hair pencil. On rubbing the said end after 
 it is dry against a rough surface, the paper will take fire without the intervention of sulphur. 
 
 T : form lueifer wood matches, that act without sulphur, melt in a flat-bottomed tin pan as much 
 white wax as will stand one-tenth of an inch deep ; take a bundle of wooden matches free from resin, 
 rub their ends against a red-hot iron plate till the wood be slightly charred ; dip them now in the 
 melted wax for a moment, shake them well on taking them out, and finally dip them separately in the 
 • above viscid paste. When dry, they will kindle readily by friction. 
 
 For the rapid manufacture of the wooden splints for lueifer matches, a patent was granted to 
 Mr. Reuben Partridge, in March, 1842. He employs a perforated metallic plate, having a steel 
 face, strengthened by a bell-metal back. The size of the perforations must depend on that of the 
 desired splints, but they must be as close together as possible, that there msfy be a very small 
 
360 
 
 MATERIALS. 
 
 blank space between them, otherwise the plate would afford too great resistance to the passage of the 
 wood. By this construction, the whole area of the block of wood may be compressed laterally into 
 the countersunk openings, and forced through the holes, which are slightly countersunk to favor the 
 entrance and separation of the wooden fibres. A convenient size of plate is three inches broad, six 
 inches long, and one thick. The mode of pressing is by fixing the back of the plate against a firm 
 resisting block or bearing, having an aperture equal to the area of the perforations in the plate, and 
 then placing the end of the piece or pieces of wood in the direction of the grain against the face of the 
 plate within the area of the perforated portion. A plunger or lever, or other suitable mechanical 
 agent, being then applied to the back or reverse end of the piece of wood, it may be forced through the 
 perforations in the plate, being first split as it advances by the cutting edges of th holes, and after- 
 wards compressed and driven through the perforations in the plate, coming out on the opposite side or 
 back of the plate in the form of a multitude of distinct splints, agreeably to the shapes and dimen- 
 sions of the perforations. 
 
 MATERIALS, properties of, used in the mechanic arts. The following tables show, in a condensed 
 form, the characteristics of materials. 
 
 Experiments on the direct Cohesive Powers of various Materials. 
 
 Names of Materials. 
 
 Cohesive 
 powers re- 
 duced to a sq 
 inch rod. 
 
 Experimenters. 
 
 Quoted from. 
 
 WOODS. 
 
 Oak 
 
 do 
 
 do. dry English from. 
 
 Beech 
 
 do 
 
 Alder 
 
 Chestnut, Spanish - .... . 
 
 Ash, very dry, from ... 
 
 do 
 
 Elm 
 
 Acacia 
 
 Mahogany 
 
 Walnut 
 
 Teak 
 
 Poplar 
 
 Fir 
 
 do. 
 
 Scotch Pine... 
 Norway Pine . 
 
 Larch 
 
 Cedar 
 
 lbs. 
 
 17.300 
 13,950 
 
 j 12,000 ) 
 \ 8,000 j 
 17,709 
 11,500 
 14,186 
 
 13.300 
 
 ( 17,850 ) 
 j 15,784 j 
 12,000 
 13,489 
 20,582 
 8,000 
 8,130 
 15,000 
 
 from 
 
 i 6.641 
 
 to 
 
 ] 4,596 
 
 from 
 
 ] 13^448 \ 
 
 to 
 
 1 11,000 
 
 METALS. 
 
 STEEL. 
 
 Cast-steel previously tilted 
 
 Cast-steel not tilted 
 
 Blistered steel reduced per hammer 
 Sheer steel reduced per hammer. . 
 
 IRON WIRE. 
 
 Iron wire 
 
 do. l-10th inch diameter 
 do 
 
 8,506 
 
 7,818 
 
 7,287 
 
 10,224 
 
 4,973 
 
 134,256 
 
 68,110 
 
 133,152 
 
 127,632 
 
 113,077 
 
 93,964 
 
 85,797 
 
 Muschenbroek. 
 
 Rondelet. 
 
 Barlow. 
 
 Muschenbroek. 
 
 Barlow. 
 
 Muschenbroek. 
 
 Rondelet. 
 
 Barlow. 
 
 Muschenbroek. 
 
 do. 
 
 do. 
 
 Barlow. 
 
 Muschenbroek. 
 
 Barlow. 
 
 Muschenbroek. 
 
 Barlow. 
 
 Muschenbroek. 
 
 do. 
 
 Rondelet. 
 
 do. 
 
 Muschenbroek. 
 
 Rennie. 
 
 Brown. 
 
 Rennie. 
 
 do. 
 
 Sickengen. 
 
 Telford. 
 
 Button. 
 
 Introd. ad Phil. Nat. 
 
 L’Art de Batir, iv. 
 
 Essay on the Strength of Timber. 
 
 Introd. ad Phil. Nat. 
 
 Essay on the Strength of Timber. 
 Introd. ad Phil. Nat. 
 
 L’Art de Batir, iv. 
 
 Essay on the Strength of Timber. 
 
 Introd. ad Phil. Nat. 
 do. 
 do. 
 
 Essay on the Strength of Timber. 
 
 Introd. ad Phil. Nat 
 
 Essay on the Strength of Timber. 
 
 Introd. ad Phil. Nat. 
 
 Essay on the Strength of Timber. 
 
 Introd. ad Phil. Nat. i. 
 do. 
 
 L’Art de Batir, iv. 
 do. 
 
 Introd. ad Phil. Nat. i 
 
 Phil. Trans, for 1813. 
 Barlow’s Essays, <tc. 
 Phil Trans, for 1818. 
 do. 
 
 Ann. de Chimie, vol. 25. 
 Barlow’s Essay, p. 245, 2d ed. 
 (Euvres de Gauthey, ii. p. 153. 
 
 MALLEABLE IRON IN BARS. 
 
 German bar, mark B R, highest 
 
 results 
 
 Swedish bar, highest result 
 
 German bar, mark L, highest result 
 
 Liege bar, highest result 
 
 Spanish bar 
 
 Oosement bar, highest result 
 
 Swedish bar reduced per hammer. 
 
 93,069 
 
 88,972 
 
 85.900 
 82,839 
 
 81.901 
 76,697 
 72,064 
 
 Muschenbroek. 
 
 do. 
 
 do. 
 
 do. 
 
 do. 
 
 do. 
 
 Rennie. 
 
 Introd. ad Phil. Nat. i. 426. 
 do. 
 do. 
 do. 
 do. 
 do. 
 
 Phil. Trans. 1818. 
 
MATERIALS. 
 
 361 
 
 Names of Materials. 
 
 Cohesive 
 powers re- 
 duced to a sq. 
 inch rod. 
 
 Experimenters. 
 
 Quoted from. 
 
 . i 
 
 Common round iron 
 
 lbs. 
 
 66,309 
 
 Telford. 
 
 Barlow’s Essay, p. 230. 
 
 German bar, marked L 
 
 69,530 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 426 
 
 Common Staffordshire bar 
 
 64,580 
 
 Telford. 
 
 Barlow’s Essay, p. 230. 
 
 Common German bar 
 
 69,133 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 426. 
 
 Swedish bar 
 
 68,728 
 
 do. 
 
 do. 
 
 Oosement bar 
 
 68,728 
 
 do. 
 
 do. 
 
 Welsh bar 
 
 62,079 
 
 Telford. 
 
 Barlow’s Essay, p. 230. 
 
 Bar of the best quality 
 
 66,000 
 
 Rumford. 
 
 Phil. Mag. x. p. 51. 
 
 A bar of Welsh, one of Swedish, 
 and one faggoted scrap iron, 
 
 
 
 each gave a result of 
 
 00,413 
 
 Telford. 
 
 Barlow’s Essay, p. 229. 
 
 The Swedish iron broke at a flaw. 
 
 
 
 Liege bar 
 
 62,369 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat, i. 426. 
 
 Staffordshire bar 
 
 57,288 
 
 Telford. 
 
 Barlow’s Essay, p. 229. 
 
 German bar, marked B It 
 
 61,361 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 426. 
 
 Bar (mean of S3 experiments) 
 
 61,041 
 
 Perronnet. 
 
 CEuvres de Gauthev, ii. 154. 
 
 Russian old sable, mark C C If.... 
 
 64,230 
 
 Brown. 
 
 Barlow’s Essay, p. 233. 
 
 English bar reduced per hammer. 
 
 65,872? 
 
 Rennie. 
 
 Phil. Trans, for 1818. 
 
 Welsh bar (3 experiments) 
 
 60,288 
 
 Brown. 
 
 Barlow’s Essay, p. 233. 
 
 Bar of good quality 
 
 66,000 
 
 Rumford. 
 
 Phil. Mag. vol. x. p. 51. 
 
 Swedish bar (3 experiments) 
 
 67,503 
 
 Brown. 
 
 Barlow’s Essay, p. 232. 
 
 CAST-IRON. 
 
 
 
 
 Bar, specific gravity 7-80 7 
 
 68,295 ? 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 417. 
 
 do. cast vertically 
 
 19,488 
 
 Rennie. 
 
 Phil. Trans, for 1818. 
 
 do. cast horizontally 
 
 18,656 
 
 do. 
 
 do. 
 
 do. Welsh pig 
 
 17,565 
 
 Brown. 
 
 Barlow’s Essay, p. 235. 
 
 COPPER. 
 
 
 
 
 Wire 
 
 61,228 
 
 Sickingen. 
 
 Ann. de Chimie, xxv. 9. 
 
 Wrought copper reduced b}' the 
 
 
 
 hammer 
 
 33,792 
 
 Rennie. 
 
 Phil. Trans, for 1818. 
 
 Cast, Barbary, spec. grav. 8T82... 
 
 22,570 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat, i. 417. 
 
 do. Japan, do. do. 8 - 726... 
 
 20 272 
 
 do. 
 
 do. 
 
 do 
 
 19,072 
 
 Rennie. 
 
 Phil. Trans, for 1818. 
 
 PLATINUM. 
 
 
 
 
 Platinum wire, spec. grav. 20-847 . 
 do. do. 
 
 56,473 
 
 Morveau. 
 
 Ann. de Chimie, xxv. 8. 
 
 62,987 
 
 Sickingen. 
 
 do. p. 9. 
 
 SILVER. 
 
 
 
 
 Silver wire 
 
 38,257 
 
 do. 
 
 do. 
 
 Silver cast, spec. grav. 11-091 
 
 40,902 
 
 Muschenbroek. 
 
 Introd. ad. Phil. Nat. 417. 
 
 GOLD. 
 
 
 
 
 Gold wire 
 
 30,888 
 
 Sickingen. 
 
 Ann. de Chimie, xxv. 9. 
 
 Gold cast, spec. grav. 19-238 
 
 20,450 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 417. 
 
 ZINC. 
 
 
 
 
 Zinc wire 
 
 22,551 
 
 Morveau. 
 
 Ann. de Chimie, lxxi. 194. 
 
 do. sheet 
 
 16,600 
 
 Tredgold. 
 
 Phil. Mag. vol. i. p. 422. 
 
 do. cast 
 
 TIN. 
 
 Tin wire 
 
 2,689 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat, i. 407. 
 
 7,129 
 
 Morveau. 
 
 Ann. de Chimie, lxxi. 194. 
 
 English block, cast 
 
 6,650 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 417. 
 
 English, spec. grav. 7'295 
 
 5,322 
 
 do. 
 
 do. 
 
 Cast 
 
 4.736 
 
 Rennie. 
 
 Phil. Trans, for 1818. 
 
 Banca tin cast, spec. grav. 7'2165 . 
 
 3,679 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat, i. 417. 
 
 Malacca tin cast, do. 6-1250. 
 
 3,211 
 
 do. 
 
 do. 
 
 LEAD. 
 
 
 
 
 Milled sheet, spec. grav. 11-407 .... 
 
 3,328 
 
 Tredgold. 
 
 Phil. Mag. vol. i. p. 422. 
 
 A\ ire 
 
 3,146 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. i. 452. 
 
 do. spec. grav. 11-282 
 
 2,581 
 
 do. 
 
 do. 
 
 do. 
 
 2,547 
 
 Morveau. 
 
 Ann. de Chimie, lxxi. 194. 
 
 Cast lead 
 
 1,824 
 
 Rennie. 
 
 Phil. Trans, for 181S. 
 
 Cast, English, spec. grav. 11-479... 
 
 885 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. L 452. 
 
3G2 
 
 MATERIALS. 
 
 Names of Materials. 
 
 Cohesive 
 powers re- 
 duced to a sq. 
 inch rod. 
 
 Experimenters. 
 
 Quoted from. 
 
 BISMUTH. 
 
 lbs. 
 
 
 
 Bismuth cast, spec. grav. 9-810 
 
 3,250 
 
 Muschenbroek. 
 
 Introd. ad Phil. Fat. i 4 "2 
 
 do. spec. grav. 9-926 
 
 3,008 
 
 do. 
 
 do. 
 
 ANTIMONY. 
 
 
 
 
 Antimony cast, spec. grav. 4-500... 
 
 1,006 
 
 do. 
 
 do. 
 
 ALLOYS. 
 
 
 
 
 Copper 10 tin 1, sp. gr. 8'351 
 
 32,093 
 
 Muschenbroek. 
 
 Introd. ad Phil. Nat. 
 
 do. 8 do. 1, do. 8-392 
 
 36,088 
 
 do. 
 
 do. 
 
 do. 6 do. 1, do. 8-707 
 
 44,071 
 
 do. 
 
 do. 
 
 do. 4 do. 1, do. 8 - 723 
 
 35,739 
 
 do. 
 
 do. 
 
 do. 2 do. 1 
 
 1,017 
 
 do. 
 
 do. 
 
 Gun metal, hard 
 
 36,368 
 
 Rennie. 
 
 Phil. Trans, for 1818. 
 
 Brass, fine yellow 
 
 17,968 
 
 do. 
 
 do. 
 
 Tin, English, 10 lead 1 
 
 6,904 
 
 Muschenbroek. 
 
 do. 
 
 do. 8 do. 1 
 
 7,922 
 
 do. 
 
 do. 
 
 do. 6 do. 1 
 
 7,997 
 
 do. 
 
 do. 
 
 do. 4 do. 1 
 
 10,607 
 
 do. 
 
 do. 
 
 do. 2 do. 1 
 
 7,470 
 
 do. 
 
 do. 
 
 do. 1 do. 1 
 
 7,074 
 
 do. 
 
 do. 
 
 sp. gr. 
 
 
 
 
 Tin, Banca, 10 Antimony 1, 7'359 
 
 11,181 
 
 do. 
 
 do. 
 
 do. 8 do. 1, 7-276 
 
 9,881 
 
 do. 
 
 do. 
 
 do. 6 do. 1, 7-228 
 
 12,632 
 
 do. 
 
 do. 
 
 do. 4 do. 1, 7-192 
 
 13,480 
 
 do. 
 
 do. 
 
 do. 2 do. 1, 7T05 
 
 12,029 
 
 do. 
 
 do. 
 
 do. 1 do. 1, 7-060 
 
 3,184 
 
 do. 
 
 do. 
 
 do. 10 bismuth 1, 7'576 
 
 12,688 
 
 do. 
 
 do. 
 
 do. 4 do. 1, 7’613 
 
 16,692 
 
 do. 
 
 do. 
 
 do. 2 do. 1, 8-076 
 
 14,017 
 
 do. 
 
 do. 
 
 do. 1 do. 1, 8-146 
 
 12,020 
 
 do. 
 
 do. 
 
 do. 1 do. 2, 8'580 
 
 10,013 
 
 do. 
 
 do. 
 
 do. 1 do. 4, 9-009 
 
 7,875 
 
 do. 
 
 do. 
 
 do. 10 zinc, Ind’n, 1, 7'288 
 
 12,914 
 
 do. 
 
 do. 
 
 do. 2 do. 1, 7-000 
 
 15,025 
 
 do. 
 
 do. 
 
 do. 1 do. 1, 7-321 
 
 15,844 
 
 do. 
 
 do. 
 
 do. 1 do. 2, 7-100 
 
 16,023 
 
 do. 
 
 do. 
 
 do. 1 do. 10, 7‘130 
 
 5,671 
 
 do. 
 
 do. 
 
 Tin, English, 8 do. Goslar, 1, 
 
 10,607 
 
 do. 
 
 do. 
 
 do. 4 do. 1, 
 
 10,258 
 
 do. 
 
 do. 
 
 do. 2 do. 1, 
 
 10,964 
 
 do. 
 
 do. 
 
 do. 1 do. 1, 
 
 9,024 
 
 do. 
 
 do. 
 
 do. 1 antimony 1, 7'000 
 
 1,450 
 
 do. 
 
 do. 
 
 do. 3 do. 2, 
 
 3,184 
 
 do. 
 
 do. 
 
 do. 4 do. 1, 
 
 11,343 
 
 do. 
 
 do. 
 
 Lead, Scotch, 1 bismuth 1 , 1 0*93 1 
 
 7,319 
 
 do. 
 
 do. 
 
 do. 2 do. 1,11-090 
 
 5,840 
 
 do. 
 
 do. 
 
 do. 10 do. 1,10-827 
 
 2,826 
 
 do. 
 
 do. 
 
 Experiments on the Pesistance of different Metals to Pressure. 
 
 Size of prism. 
 
 Name of Metal. 
 
 Crushing 
 
 weight 
 
 Remarks. 
 
 Size of base. Height. 
 
 inch. inch. 
 
 lMth. l-4th. 
 
 do. do. 
 
 do. do. 
 
 do. do. 
 
 do. do. 
 
 Cast copper. 
 Brass. 
 
 Wrought copper. 
 
 Cast tin. 
 
 Cast lead. 
 
 lbs. 
 
 7,318 
 
 10,304 
 
 6,440 
 
 966 
 
 483 
 
 Crumbled by pressure. 
 
 ( Fine yellow brass reduced onc-tenth by 3213 
 } lbs, and one-half with 10,304 lbs. 
 j Reduced one-sixteenth with 3427 lbs., one- 
 I eighth with 6440 lbs. 
 
 j Reduced one-sixteenth with 552 lbs, one- third 
 l with 960 lbs. 
 
 Reduced one-half with 483 lbs. 
 
MATERIALS. 
 
 3G8 
 
 Experiments on the Resistance of Cast-iron to Pressure. 
 
 Size of prism. 
 
 Specific 
 
 Crushing 
 
 zq of base. 
 
 Height. 
 
 gravity. 
 
 weight. 
 
 inch. 
 
 inch. 
 
 
 lbs. 
 
 1-Stll. 
 
 1-8 th. 
 
 7033 
 
 1,454 
 
 do. 
 
 do. 
 
 do. 
 
 1,416 
 
 do. 
 
 do. 
 
 do. 
 
 1,449 
 
 do. 
 
 2-8ths. 
 
 6977 
 
 1,922 
 
 do. 
 
 do. 
 
 do. 
 
 2,310 
 
 do. 
 
 3-8ths. 
 
 do. 
 
 2,363 
 
 do. 
 
 4-8ths. 
 
 do. 
 
 2,005 
 
 do. 
 
 5-8ths. 
 
 do. 
 
 1,407 
 
 do. 
 
 6-8ths. 
 
 do. 
 
 1,743 
 
 do. 
 
 7-8ths. 
 
 do. 
 
 1,594 
 
 do. 
 
 8-8ths. 
 
 do. 
 
 1,439 
 
 l-4th. 
 
 l-4th. 
 
 do. 
 
 10,561 
 
 do. 
 
 do. 
 
 do. 
 
 9,596 
 
 do. 
 
 do. 
 
 do. 
 
 9,917 
 
 do. 
 
 do. 
 
 do. 
 
 9,020 
 
 do. 
 
 do. 
 
 7013 
 
 12,665 
 
 do. 
 
 do. 
 
 do. 
 
 10,720 
 
 do. 
 
 do. 
 
 do. 
 
 10,605 
 
 do. 
 
 do. 
 
 do. 
 
 8,699 
 
 do. 
 
 do. 
 
 7074 
 
 12,665 
 
 do. 
 
 do. 
 
 do. 
 
 10,950 
 
 do. 
 
 do. 
 
 do. 
 
 11,088 
 
 do. 
 
 do. 
 
 do. 
 
 9,844 
 
 do. 
 
 do. 
 
 do. 
 
 11,096 
 
 do. 
 
 l-2d. 
 
 }H 
 
 9,455 
 
 do. 
 
 do. 
 
 9,374 
 
 do. 
 
 do. 
 
 1 7074 j 
 
 9,938 
 
 do. 
 
 do. 
 
 10,027 
 
 do. 
 
 3-8ths. 
 
 7113 
 
 9,006 
 
 do. 
 
 5-8ths. 
 
 do. 
 
 8,845 
 
 do. 
 
 6-8 ths. 
 
 do. 
 
 8,362 
 
 do. 
 
 7-8ths. 
 
 do. 
 
 6,430 
 
 do. 
 
 8-8ths. 
 
 do. 
 
 6,321 
 
 do. 
 
 3-8ths. 
 
 7074 
 
 9,328 
 
 do. 
 
 5-8ths. 
 
 do. 
 
 8,385 
 
 do. 
 
 6-8ths. 
 
 do. 
 
 7,896 
 
 do. 
 
 7 -8 ths. 
 
 do. 
 
 7,018 
 
 do. 
 
 8-8ths. 
 
 do. 
 
 6,430 
 
 Mean from 
 each set. 
 
 Remarks. 
 
 lbs. 
 
 | 1,440 | 
 [ 2,116 
 
 1,758 | 
 
 | 9,773 | 
 10,114 | 
 11,136 | 
 
 ,414 
 
 f “• 
 
 t 9,982 
 
 These specimens were from one 
 block. 
 
 Iron from a block. 
 
 These specimens were from the 
 same block. 
 
 These specimens were from the 
 same block as the above. 
 
 These specimens were from hori- 
 zontal castings. 
 
 These specimens were vertical 
 castings. 
 
 Horizontal casting. 
 Vertical casting. 
 
 Horizontal castings. 
 Vertical castings. 
 
 The Experimental Strength of various species of Timber opposed to a Transverse Strain. 
 
 Kinds of Wood. 
 
 Specific 
 
 Gravity. 
 
 Length in 
 feet. 
 
 Breadth 
 
 in 
 
 inches. 
 
 Depth in 
 inches. 
 
 Deflec- 
 tion at 
 the time 
 of frac- 
 ture. 
 
 Break- 
 
 ing 
 
 weight 
 in lbs. 
 
 Value of 
 constant 
 strength. 
 
 Authorities. 
 
 Oak, English, young tree 
 
 •863 
 
 2* 
 
 i 
 
 i 
 
 1-87 
 
 482 
 
 2892 
 
 Tredgold. 
 
 l)o. old ship timber 
 
 •872 
 
 2*5 
 
 i 
 
 i 
 
 1-5 
 
 264 
 
 1980 
 
 do. 
 
 Do. from old tree 
 
 •625 
 
 2* 
 
 i 
 
 i 
 
 1-38 
 
 218 
 
 1308 
 
 do. 
 
 Do. medium quality 
 
 •748 
 
 2-5 
 
 i 
 
 i 
 
 
 284 
 
 2130 
 
 Ebbels. 
 
 Do. green 
 
 •763 
 
 2-5 
 
 i 
 
 i 
 
 
 219 
 
 1741 
 
 do. 
 
 Do. do 
 
 1-063 
 
 11*75 
 
 8‘5 
 
 8-5 
 
 3-2 
 
 24812 
 
 1785 
 
 Buffon. 
 
 Beech, medium quality 
 
 •690 
 
 2-5 
 
 i 
 
 1 
 
 
 271 
 
 2031 
 
 Ebbels. 
 
 Alder 
 
 '555 
 
 2-5 
 
 i 
 
 1 
 
 
 212 
 
 1590 
 
 do. 
 
 Plane tree 
 
 •648 
 
 2'5 
 
 i 
 
 1 
 
 
 243 
 
 1821 
 
 do. 
 
 Sycamore 
 
 •590 
 
 2-5 
 
 i 
 
 1 
 
 
 214 
 
 1605 
 
 do. 
 
 Chestnut tree 
 
 ■875 
 
 2-5 
 
 i 
 
 1 
 
 
 180 
 
 1350 
 
 do. 
 
 Ash, from young tree 
 
 •811 
 
 2-5 
 
 i 
 
 1 
 
 2-5 
 
 324 
 
 2430 
 
 Tredgold. 
 
 Do. medium quality 
 
 •690 
 
 2-5 
 
 i 
 
 1 
 
 
 254 
 
 1905 
 
 Ebbels. 
 
 Ash 
 
 ■753 
 
 2'5 
 
 i 
 
 1 
 
 2-38 
 
 314 
 
 2355 
 
 Tredgold. 
 
 Elm, common 
 
 •544 
 
 2-5 
 
 i 
 
 1 
 
 
 216 
 
 1620 
 
 Ebbels. 
 
 Do. weych, green 
 
 •763 
 
 2-5 
 
 i 
 
 1 
 
 
 192 
 
 1440 
 
 do. 
 
 Acacia, green 
 
 •820 
 
 2-5 
 
 i 
 
 1 
 
 
 249 
 
 1866 
 
 do. 
 
 Mahogany, Spanish, seasoned. 
 
 •862 
 
 2-5 
 
 i 
 
 1 
 
 
 170 
 
 1275 
 
 Tredgold. 
 
 Do. Honduras, seasoned 
 
 •256 
 
 2 5 
 
 i 
 
 1 
 
 
 255 
 
 1911 
 
 do. 
 
364 
 
 MATERIALS. 
 
 Exhibiting the Experimental Strength of various Species of Timber, etc. — Cont inued. 
 
 Kinds of Wood. 
 
 Specific 
 
 Gravity. 
 
 Length in 
 feet. 
 
 Breadth 
 
 in 
 
 inches. 
 
 Depth in 
 inches. 
 
 Deflec- 
 tion at 
 the time 
 of frac- 
 ture. 
 
 Break- 
 
 ing 
 
 weight 
 in lbs. 
 
 Value of 
 constant 
 strength. 
 
 Authorities. 
 
 Walnut, green 
 
 •925 
 
 2-5 
 
 i 
 
 i 
 
 
 195 
 
 1461 
 
 Ebbels. 
 
 Poplar, Lombardv 
 
 •375 
 
 2*5 
 
 i 
 
 i 
 
 
 131 
 
 981 
 
 do. 
 
 Do. Abele 
 
 •511 
 
 25 
 
 i 
 
 i 
 
 1-5 
 
 228- 
 
 1710 
 
 Tredgold. 
 
 Teak 
 
 •744 
 
 7 
 
 2 
 
 2 
 
 4-00 
 
 820 
 
 2151 
 
 Barlow. 
 
 Willow 
 
 •405 
 
 25 
 
 i 
 
 i 
 
 3 
 
 146 
 
 1095 
 
 Tredgold. 
 
 Birch 
 
 ■720 
 
 2-5 
 
 i 
 
 i 
 
 
 207 
 
 1551 
 
 Ebbels. 
 
 Cedar of Libanus, dry 
 
 •586 
 
 * 2-5 
 
 i 
 
 i 
 
 2-75 
 
 165 
 
 1236 
 
 Tredgold. 
 
 Riga fir 
 
 •480 
 
 2-5 
 
 i 
 
 i 
 
 1-3 
 
 212 
 
 1590 
 
 do. 
 
 Memel fir 
 
 •553 
 
 2 5 
 
 i 
 
 i 
 
 1-15 
 
 218 
 
 1635 
 
 do. 
 
 Norway fir from Longsound ... 
 
 •639 
 
 2 
 
 i 
 
 i 
 
 1-125 
 
 396 
 
 2376 
 
 do. 
 
 Mar forest fir 
 
 ■715 
 
 7 
 
 2 
 
 2 
 
 55 
 
 360 
 
 945 
 
 Barlow. i 
 
 Scotch fir, English growth 
 
 •529 
 
 25 
 
 i 
 
 i 
 
 1-75 
 
 233 
 
 1746 
 
 Tredgold. 
 
 Do. do. . 
 
 •460 
 
 2-5 
 
 i 
 
 i 
 
 
 157 
 
 1176 
 
 Ebbels. 
 
 Christiana white deal 
 
 •512 
 
 2 
 
 i 
 
 i 
 
 •937 
 
 343 
 
 2058 
 
 Tredgold. 
 
 American white spruce 
 
 •465 
 
 2 
 
 i 
 
 i 
 
 1-362 
 
 285 
 
 1710 
 
 
 Spruce fir, British growth 
 
 •555 
 
 2-5 
 
 i 
 
 i 
 
 
 186 
 
 1395 
 
 Ebbels. 
 
 American pine 
 
 •460 
 
 2-0 
 
 i 
 
 i 
 
 1-125 
 
 329 
 
 1974 
 
 TrecVold. 
 
 Larch, choice specimen 
 
 •640 
 
 2-5 
 
 i 
 
 i 
 
 3-0 
 
 253 
 
 1896 
 
 do. 
 
 Do. medium quality 
 
 •622 
 
 2-5 
 
 i 
 
 i 
 
 
 223 
 
 1671 
 
 do. 
 
 Do. very young wood 
 
 •396 
 
 2-5 
 
 i 
 
 i 
 
 1-78 
 
 129 
 
 966 
 
 do. 
 
 English oak.. 
 
 •934 
 
 7 
 
 2 
 
 2 
 
 8-1 
 
 637 
 
 1672 
 
 Barlow. 
 
 Canadian do 
 
 •872 
 
 7 
 
 2 
 
 2 
 
 60 
 
 673 
 
 1766 
 
 do. 
 
 Dantzic do 
 
 •756 
 
 7 
 
 2 
 
 2 
 
 4-86 
 
 560 
 
 1457 
 
 do. 
 
 Adriatic do 
 
 •993 
 
 7 
 
 2 
 
 2 
 
 5-73 
 
 526 
 
 1383 
 
 do. 
 
 Ash 
 
 •760 
 
 7 
 
 2 
 
 2 
 
 8-92 
 
 772 
 
 2026 
 
 do. 
 
 Beech 
 
 ■696 
 
 7 
 
 2 
 
 2 
 
 5-73 
 
 593 
 
 1556 
 
 do. 
 
 Pitch pine 
 
 •660 
 
 7 
 
 2 
 
 2 
 
 6-00 
 
 622 
 
 1632 
 
 do. 
 
 Red pine 
 
 •657 
 
 7 
 
 2 
 
 2 
 
 5-83 
 
 511 
 
 1341 
 
 do. 
 
 New England pine 
 
 ■553 
 
 1 
 
 2 
 
 2 
 
 4*66 
 
 420 
 
 1102 
 
 do. 
 
 Of Experiments on the Stiffness of different Woods. 
 
 Kinds of Wood. 
 
 Specific 
 
 Gravity. 
 
 Length in 
 feet. 
 
 Breadth 
 
 in 
 
 inches. 
 
 Depth in 
 inches. 
 
 Deflec- 
 
 tion. 
 
 Weight 
 which 
 produ- 
 ced de- 
 flection. 
 
 Value of a 
 from a — 
 40 bd?Z 
 
 h w 
 
 Authorities. 
 
 Ash, young tree, white colored 
 
 •811 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 141 
 
 •009 
 
 Tredgold. 
 
 Do. old tree, red colored 
 
 •753 
 
 2 5 
 
 i 
 
 i 
 
 0*5 
 
 113 
 
 •0113 
 
 do. 
 
 Do. medium quality 
 
 •690 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 78-5 
 
 ■0163 
 
 Ebbels. 
 
 Ash 
 
 ■760 
 
 7 
 
 2 
 
 2 
 
 1-27 
 
 225 
 
 •0105 
 
 Barlow. 
 
 Beech 
 
 •688 
 
 7 
 
 2 
 
 2 
 
 1-025 
 
 150 
 
 •01277 
 
 do. 
 
 Teak 
 
 •744 
 
 7 
 
 2 
 
 2 
 
 1-276 
 
 300 
 
 ■0076 
 
 do. 
 
 Elm | 
 
 •540 
 
 2-5 
 
 2 
 
 2 
 
 1-42 
 
 125 
 
 •0212 
 
 do. 
 
 •544 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 99-5 
 
 •0128 
 
 Ebbels. 
 
 Cedar of Libanus 
 
 •486 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 36 
 
 •0355 
 
 Tredgold. 
 
 Maple, common 
 
 Abele 
 
 •625 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 65 
 
 ■0197 
 
 do. 
 
 ■511 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 84 
 
 •0152 
 
 do. 
 
 Willow 
 
 •405 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 41 
 
 •031 
 
 do. 
 
 Horse chestnut 
 
 •483 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 79 
 
 •0162 
 
 do. 
 
 Lime tree 
 
 ■483 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 84 
 
 •0152 
 
 do. 
 
 Walnut, green 
 
 •920 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 62 
 
 •020 
 
 Ebbels. 
 
 Chestnut, Spanish 
 
 •895 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 68-5 
 
 •0187 
 
 do. 
 
 Acacia 
 
 •820 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 125 
 
 ■0102 
 
 do. 
 
 Plane, dry 
 
 •648 
 
 2*5 
 
 i 
 
 i 
 
 0*5 
 
 995 
 
 ■0128 
 
 do. 
 
 Alder, do 
 
 ■555 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 80-5 
 
 •0159 
 
 do. 
 
 Birch, do 
 
 ■720 
 
 2-5 
 
 i 
 
 i 
 
 05 
 
 90-5 
 
 •0141 
 
 do. 
 
 Wycli elm, green 
 
 •763 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 92 
 
 •014 
 
 do. 
 
 Lombardy poplar, dry 
 
 •374 
 
 2*5 
 
 i 
 
 i 
 
 0*5 
 
 56-5 
 
 •0224 
 
 do. 
 
 Mahogany, Honduras 
 
 •560 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 118 
 
 •0109 
 
 Tredgold. 
 
 Do. Spanish 
 
 •853 
 
 2-5 
 
 i 
 
 i 
 
 05 
 
 93 
 
 •0137 
 
 do. 
 
 Sycamore 
 
 •590 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 76 
 
 •0168 
 
 Ebbels. 
 
 Pear, green 
 
 •792 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 59-5 
 
 •0215 
 
 do. 
 
 Cherry, do 
 
 •690 
 
 2-5 
 
 i 
 
 i 
 
 0*5 
 
 92-5 
 
 •0138 
 
 do. 
 
 Beech, dry 
 
 •696 
 
 2 5 
 
 i 
 
 i 
 
 0-5 
 
 97-5 
 
 •0131 
 
 do. 
 
MATERIALS. 
 
 365 
 
 Of Experiments on the Stiffness of Fir. 
 
 Kinds of Fir. 
 
 Specific 
 
 Gravity. 
 
 | 
 
 Length in 
 feet. 
 
 Breadth 
 
 in 
 
 inches. 
 
 Depth in 
 inches. 
 
 Deflec- 
 tion in 
 inches. 
 
 Weight 
 producing 
 the de- 
 flection in 
 lbs. 
 
 Value of a 
 from 
 40 bd?S 
 
 P w 
 
 Authorities. 
 
 Fir, Riga, yellow medium 
 
 Do. Norway 
 
 Do. Riga, yellow 
 
 iDo. Memel medium 
 
 American pine 
 
 White spruce, Christiana 
 
 Do. Quebec 
 
 Pitch pine 
 
 Fir, New England 
 
 Riga fir 
 
 Mar forest, Scotland 
 
 Larch, Blair, Scotland, dry .... 
 
 Do. seasoned medium 
 
 Do. very young wood 
 
 Scots fir 
 
 Spruce, British 
 
 Fir, (bois-disbrin) 
 
 Do. do. 
 
 .6398 
 j -480 
 | -464 
 t -553 
 \ -544 
 l -460 
 l -407 
 ■512 
 ■465 
 •712 
 •560 
 •765 
 •715 
 •622 
 $ -644 
 \ 554 
 •396 
 •529 
 •555 
 
 1-8 
 
 2 
 
 25 
 
 2-5 
 
 2'5 
 
 25 
 
 2 
 
 3 
 
 o 
 
 2 
 
 7 
 
 7 
 
 7 
 
 7 
 
 2'5 
 
 25 
 
 25 
 
 2-5 
 
 25 
 
 2'5 
 
 21-3 
 
 10'65 
 
 2 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 2 
 
 2 
 
 2 
 
 2 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 10-48 
 
 10-58 
 
 7 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 2 
 
 2 
 
 2 
 
 2 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 10-48 
 
 10-48 
 
 0-25 
 
 0-5 
 
 0-5 
 
 0-5 
 
 0’5 
 
 0-5 
 
 0-5 
 
 05 
 
 0- 5 
 0'5 
 
 1- 33 
 ■970 
 •912 
 
 1‘560 
 
 0'5 
 
 0’5 
 
 0-5 
 
 0'5 
 
 0- 5 
 0'5 
 
 1- 02 
 0-2245 
 
 103 
 
 261 
 
 123 
 
 116 
 
 143 
 
 145 
 
 237 
 
 69 
 
 261 
 
 180 
 
 150 
 
 150 
 
 150 
 
 125 
 
 93 
 
 101 
 
 112 
 
 45 
 
 89 
 
 93 
 
 4-389 
 
 4-122 
 
 •0015 
 
 •00957 
 
 •0102 
 
 •0110 
 
 •0089 
 
 •0088 
 
 •0105 
 
 •0112 
 
 •00957 
 
 •0130 
 
 •0166 
 
 •0121 
 
 •01137 
 
 •0233 
 
 •0137 
 
 •0126 
 
 ■0111 
 
 •0284 
 
 •01437 
 
 •0124 
 
 •0115 
 
 •0220 
 
 Tredgold. 
 
 Do. 
 
 Do. 
 
 Ebbels. 
 
 ) | 
 > Tredgold.; 
 
 s ° 
 
 ( Do. 
 
 Do. 
 
 Do. 
 
 Barlow. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Tredgold. 
 
 Do. 
 
 Ebbels. 
 
 Tredgold. 
 
 Do. 
 
 Ebbels. 
 
 Girard. 
 
 Do. 
 
 Experiments on the Resistance of various Materials to a Crushing Force. 
 
 Names of Materials. 
 
 Specific 
 
 Gravity. 
 
 Crushing 
 
 weight. 
 
 1. Elm, cube of 1 inch 
 
 
 lbs. 
 
 1284 
 
 2. American pine, do 
 
 
 1606 
 
 3. White deal, do. 
 
 
 1928 
 
 4. English oak, do 
 
 
 3860 
 
 5. Portland stone, 2 inches long 
 
 
 805 
 
 6. Statuary marble, 1 inch 
 
 
 3216 
 
 7. Craigleith, do 
 
 
 8688 
 
 8. Chalk, cube of 1 J inch 
 
 
 1127 
 
 9. Brick, pale red, do 
 
 2085 
 
 1265 
 
 1 0. Roe-stone, Gloucestershire, do 
 
 
 1449 
 
 11. Red brick, do. 
 
 2168 
 
 1817 
 
 1 2. Do. Hammersmith pavior’s do 
 
 
 2254 
 
 13. Burnt do. 
 
 
 3243 
 
 14. Fire brick, do. 
 
 
 3864 
 
 15. Derby grit, do. 
 
 2316 
 
 7070 
 
 16. Do. another specimen, do 
 
 2428 
 
 9776 
 
 17. Killaly white freestone, do 
 
 2423 
 
 10264 
 
 18. Portland do 
 
 2428 
 
 102S4 
 
 19. Craigleith white freestone, do 
 
 2452 
 
 12346 
 
 20. Yorkshire paving with the strata, do. 
 
 2507 
 
 12856 
 
 21. Do. do. against strata, do : . 
 
 
 12856 
 
 22. White statuary marble, do 
 
 2760 
 
 13632 
 
 23. Bramlev Fall sandstone, do 
 
 2506 
 
 13632 
 
 24. Do. against strata, do 
 
 
 1 3632 
 
 25. Cornish granite, do 
 
 2662 
 
 14302 
 
 26. Dundee sandstone, do 
 
 2530 
 
 14918 
 
 27. Portland, a two inch cube 
 
 2423 
 
 14918 
 
 28. Craigleith, with the strata, 1^ inch cube 
 
 2452 
 
 15860 
 
 29. Devonshire red marble 
 
 
 16732 
 
 30. Compact limestone 
 
 2584 
 
 17354 
 
 31. Granite Peterhead 
 
 
 18636 
 
 32. Black compact limestone 
 
 2598 
 
 19924 
 
 33. Purbeck 
 
 2599 
 
 2528 
 
 20610 
 
 21254 
 
 34. Freestone, very hard 
 
 35. Black Brabant marble 
 
 2697 
 
 20742 
 
 - 36. White Italian marble 
 
 2726 
 
 21783 
 
 1 37. Granite, Aberdeen, Blue kind 
 
 2625 
 
 24556 
 
3G6 
 
 MATERIALS. 
 
 Of Experiments on the Stiffness of Oaf. 
 
 Kinds of Oak. 
 
 Specific 
 
 Gravity. 
 
 Length in 
 feet. 
 
 Breadth 
 
 in 
 
 inches. 
 
 Depth in 
 inches. 
 
 Deflec- 
 tion in 
 inches. 
 
 Weight 
 producing 
 the de- 
 flection in 
 lbs. 
 
 Values of 
 a from 
 40 bd?S 
 12 W 
 
 Authorities. 
 
 
 X 
 
 -I 
 
 to 
 
 2-5 
 
 i 
 
 i 
 
 0-5 
 
 127 
 
 •00998 
 
 Tredgold. 
 
 Do. 
 
 Oak from young tree, King’s 
 
 •863 
 
 2* 
 
 i 
 
 i 
 
 0-5 
 
 237 
 
 •0105 
 
 Oak from Beaulieu, Hants .... 
 
 •616 
 
 •736 
 
 2*5 
 
 2*5 
 
 i 
 
 i 
 
 1 
 
 1 
 
 0-5 
 
 0-5 
 
 78 
 
 65 
 
 ■0164 
 
 •0197 
 
 Do. 
 
 Do. 
 
 
 •625 
 
 2 
 
 i 
 
 i 
 
 
 103 
 
 ■0240 
 
 Do. 
 
 
 •688 
 
 o 
 
 i 
 
 1 
 
 
 233 
 
 •0107 
 
 *0119 
 
 Do. 
 
 
 •960 
 
 7 
 
 2 
 
 2 
 
 1-275 
 
 270 
 
 Barlow. 
 
 Do. 
 
 
 •867 
 
 7 
 
 2 
 
 9 
 
 1-07 
 
 225 
 
 •009 
 
 
 ■787 
 
 7 
 
 2 
 
 9 
 
 1-26 
 
 208 
 
 •0105 
 
 Do. 
 
 
 ■948 
 
 7 
 
 2 
 
 9 
 
 
 150 
 
 •0193 
 
 
 
 •763 
 
 
 1 
 
 1 
 
 0-5 
 
 0*5 
 
 96 
 
 *0133 
 
 
 
 •755 
 
 2-5 
 
 1 
 
 1 
 
 148 
 
 •0087 
 
 •008 
 
 
 
 12-8 
 
 .3-19 
 
 3-19 
 
 \ 1-06 
 
 268 
 
 | Aubry. 
 
 
 
 6-87 
 
 5-3 
 
 5-3 
 
 ( 4-25 
 •433 
 
 803 
 
 7587 
 
 •0105 
 
 •005 
 
 Do. do 
 
 
 23'58 
 
 53 
 
 5-3 
 
 2-7 
 
 706 
 
 •0095 
 
 Do. 
 
 Do. 
 
 
 8-52 
 
 5-06 
 
 6-22 
 
 0-709 
 
 4146 
 
 ■0013 
 
 
 
 
 1606 
 
 10-66 
 
 11-73 
 
 0-67 
 
 
 •02 1 3 
 
 Do 
 
 Oak 
 
 
 9 
 
 1 
 
 1 
 
 0-35 
 
 149 
 
 •0117 
 
 Tredgold. 
 
 Do. 
 
 |Do 
 
 
 9 
 
 1 
 
 1 
 
 0-35 
 
 167 
 
 •0104 
 
 
 
 
 
 
 Experiments on the Resistance of Seasoned Oak Beams to Forces pressing in the direction of their lengths. 
 
 Kind of Wood. 
 
 fcO 
 
 ►3 
 
 Breadth in inch. 
 
 Depth in inches. 
 
 Oak seasoned . ... ^ 
 
 2.125 
 
 2-126 
 
 2-126 
 
 Do 
 
 4-25 
 
 2T26 
 
 2-126 
 
 Do 
 
 6-375 
 
 2-126 
 
 2-120 
 
 Do 
 
 2-125 
 
 3-18 
 
 ST8 
 
 Do 
 
 4-25 
 
 SIS 
 
 3-18 
 
 Do 
 
 6-375 
 
 3-18 
 
 3-18 
 
 Do 
 
 2.125 
 
 4-25 
 
 4-25 
 
 Do 
 
 4-25 
 
 4-25 
 
 4-25 
 
 Do 
 
 6-375 
 
 4-25 
 
 4-25 
 
 o 
 
 CD 
 
 6 3 
 ■~3 o 
 
 O £ 
 
 IT-3 
 
 ■— QJ 
 
 'o ^ 
 
 Proportional 
 
 elasticity. 
 
 Duration of the 
 experiments in 
 hours. 
 
 ’3 o 
 p 
 
 3 
 
 •0787 
 
 7,856 
 
 •0006 
 
 4 
 
 15-631 
 
 •03937 
 
 13,525 
 
 •00033 
 
 6 
 
 21-296 
 
 •1181 
 
 14,119 
 
 •00032 
 
 18 
 
 19-993 
 
 •03937 
 
 11,750 
 
 •00042 
 
 8 
 
 21-060 
 
 -0787 
 
 6,298 7 
 
 
 r - 1 
 
 11-844 
 
 •1574 
 
 6,298 1 
 
 
 1 27 
 
 12-225 
 
 •1574 
 
 6,298 | 
 
 
 1 
 
 13565 
 
 •1574 
 
 6,298 J 
 
 
 l 6 
 
 12-458 
 
 •1574 
 
 3,277 
 
 •00015 
 
 6 
 
 7-244 
 
 •1574 
 
 2,860 
 
 •00018 
 
 
 7-484 
 
 ■2361 
 
 2,750 j 
 
 
 5 
 
 8-492 
 
 •1574 
 
 2,750 j 
 
 
 
 7-878 
 
 •0787 
 
 34,599 
 
 •0007 
 
 27 
 
 50-958 
 
 "03937 
 
 45,168 
 
 •0006 
 
 24 
 
 50-958 
 
 •1574 
 
 20,317 
 
 •0003 
 
 29 
 
 43-639 
 
 ■1574 
 
 18,647 
 
 •00031 
 
 5 
 
 36'865 
 
 •19685 
 
 20,578 
 
 •0003 
 
 9 
 
 36-205 
 
 •27559 
 
 21,819 
 
 •00026 
 
 17 
 
 28-182 
 
 •1574 
 
 9,121 
 
 •00028 
 
 7 
 
 26-939 
 
 •19685 
 
 9,713 
 
 •00027 
 
 19 
 
 28-987 
 
 •0787 
 
 11,000 
 
 •00023 
 
 4 
 
 23-929 
 
 ■2361 
 
 10,142 
 
 •00025 
 
 18 
 
 33-048 
 
 •1574 
 
 12,746 
 
 •0002 
 
 6 
 
 36-902 
 
 •0787 
 
 61,883 
 
 •00118 
 
 11 
 
 95-262 
 
 •03937 
 
 56,691 ) 
 
 
 8 
 
 66-112 
 
 •03937 
 
 56,693 J 
 
 
 23 
 
 105-826 
 
 •0787 
 
 67,467 
 
 •00107 
 
 28 
 
 94-476 
 
 •03937 
 
 57,780 
 
 •00125 
 
 30 
 
 88-442 
 
 •03937 
 
 63,066 
 
 •00027 
 
 8 
 
 100-755 
 
 •0787 
 
 29,695 
 
 •0006 
 
 5 
 
 85-998 
 
 •0787 
 
 50,525 
 
 •00035 
 
 19 
 
 73-238 
 
 •03937 
 
 45,201 
 
 •0004 
 
 19 
 
 96-368 
 
 •1574 
 
 21,589 
 
 •00038 
 
 7 
 
 64-090 
 
 •2361 
 
 17,331 
 
 ■00047 
 
 5 
 
 59-373 
 
 •1574 
 
 IS, 517 
 
 •00044 
 
 oo 
 
 54-062 
 
 •2361 
 
 27,599 
 
 ■0003 
 
 22 
 
 65-608 
 
 ► Lamande. 
 
 - Do. 
 
 Do. 
 
 Do. 
 
 - Do. 
 
 - Do. 
 
 Do. 
 
 ■ Do. 
 
 {- Do. 
 
MECHANICAL POWERS. 
 
 3G7 
 
 On the Elasticity of various Woods, as computed by Mr. Tredgold. 
 
 Kinds of Wood. 
 
 English oak 
 
 Beech 
 
 Alder 
 
 Chestnut, green 
 
 Ash 
 
 Elm 
 
 Acacia 
 
 Mahogany, Spanish 
 
 Elasticity 
 
 0'0015 
 
 0-00195 
 
 0-0023 
 
 0-00267 
 
 0-00168 
 
 0-00184 
 
 0-00152 
 
 0-00205 
 
 Kinds of Wood. 
 
 Elasticity 
 = e. 
 
 
 0-00161 
 
 
 0-00118 
 
 
 00063 
 
 Riga fir 
 
 0-00152 
 
 Memel fir 
 
 0-00133 
 
 
 0-00142 
 
 
 000157 
 
 
 0-0019 
 
 
 MEAN. A middle state between two extremes ; thus we say, arithmetical mean is half the sum of 
 any two quantities : as < —z — = arithmetical mean between a and b. 
 
 Geometrical mean is the square root of the product of any two quantities ; that is, a b is the geo- 
 metrical mean between a and b. 
 
 MEASURE. Measure denotes any certain quantity with which other homogeneous quantities are 
 compared. — See Weights and Measures. 
 
 MECHANICAL POWERS. Power is a compound of weight, multiplied by its velocity ; it cannot 
 be increased by mechanical means. 
 
 The weight is the resistance to be overcome, the power is the requisite force to overcome that resist- 
 ance. When they are equal, no motion can take place. 
 
 The powers are three in number, viz., Lever, Inclined Plane, and Pulley. 
 
 Note. — The wheel and axle is a continual or revolving lever, the wedge is a double inclined plane, 
 and the screw is a revolving inclined plane. 
 
 Lever. — When trie f ulcrum (or support) of the lever is between the weight and the power. 
 
 Rule . — Divide the weight to be raised by the power, and the quotient is the difference of leverage, 
 or the distance from the fulcrum at which the power supports the weight. 
 
 Or, multiply the weight by its distance from the fulcrum, and the power by its distance from the 
 same point, and the weight and power will be to each other as their products. 
 
 Example . — A weight of 1600 lbs. is to be raised by a force of 80 lbs. ; required the length of the 
 longest arm of the lever, the shortest being 1 foot. 
 
 1600X1 
 
 80 
 
 = 20 feet, A ns. 
 
 Proof, by second rule. 
 
 1600X 1 =1600. 
 
 80X20 = 1600. 
 
 Example. — A weight of 2460 lbs. is to be raised with a lever 7 feet long and 300 lbs. ; at what part 
 of the lever must the fulcrum be placed ? 
 
 2460 7X12 84 
 
 7 — 8-2 ; that is, the weight is to the power as 8’2 to 1 ; therefore the whole length - — - — = — = 
 
 300 ’ ’ 13 1 ’ ° 8-2 + 1 9-2 
 
 9-13 inches, the distance of the fulcrum from the weight. 
 
 Example. — A weight of 400 lbs. is placed 1 5 inches from the fulcrum of a lever ; what force will 
 raise it, the length of the other arm being 10 feet? 
 
 400x15 rn IK < 
 
 = 50 lbs., A ns. 
 
 120 
 
 Note . — Pressure upon fulcrum equal the sum of weight and power. 
 
 When the fulcrum is at one extremity of the lever, and the power, or the weight, at the other. 
 
 Ride. — As the distance between the power or weight and fulcrum, is to the distance between the 
 weight or power and fulcrum, so is the effect to the power, or the power to the effect. 
 
 Example. — What power will raise 1500 lbs., the weight being 5 feet from it, and 2 feet from the 
 fulcrum ? 
 
 5 + 2 = 7 : 2 : : 1500 : 428-5714 + Ans. 
 
 Example. — What is the weight on each support of a beam that is 30 feet long, supported at both 
 ends, and bearing a weight of 6000 lbs. 10 feet from one end ? 
 
 30 : 20 : : 6000 : 4000 lbs. at the end nearest the weight ; and 
 30 : 10 : : 6000 : 2000 lbs. at the end farthest from the weight. 
 
 Note. — Pressure upon fulcrum is the difference of the weight and the power. 
 
 The General Rule, therefore, for ascertaining the relation of Power to Weight in a lever, whether 
 it be straight or curved, is, the power multiplied by its distance from the fulcrum, is equal to the weight 
 multiplied by its distance from the fulcrum. 
 
368 
 
 MECHANICAL POWERS. 
 
 Let P be called the power, W the weighty the distance of P from the fulcrum, and w the distance 
 of W from the fulcrum ; then 
 
 and 
 
 P : W : ; w : p, or P Xp = WX»; 
 
 1YX» 
 
 P Xp _ 
 
 w. 
 
 -='[>■ 
 
 P Xp 
 
 ~W~ w ' 
 
 If several weights or powers act upon one or both ends of the lever, the condition of equilibrium is 
 PXp-f P'Xjo' + P "Xp", <fec., = WX» + W'Xai', Ac. 
 
 In a system of levers, either of similar, compound, or mixed kinds, the condition is 
 
 P XpXp'Xp" _ w 
 wXw'Xw" 
 
 Let P = 1 lb., p and p' each 10 feet, p" 1 foot ; and if w and w' be each 1 foot, and w" 1 inch, then 
 
 1X120X120X12 172800 
 
 - = = 1200 ; that is, 1 lb. will balance 1200 lbs. with levers of the lengths 
 
 11! X 1-iXI 1 44 
 
 above given. 
 
 Note. — The weights of the levers in the above formulae are not considered, the centre of gravity being 
 assumed to be over the fulcrums. 
 
 If the arms of the lever be equally bent or curved, the distances from the fulcrum must be measured 
 upon perpendiculars, drawn from the lines of direction of the weight and power, to a line running hori- 
 zontally through the fulcrum ; and if unequally curved, measure the distances from the fulcrum upon a 
 line running horizontally through it till it meets perpendiculars falling from the ends of the lever. 
 
 Wheel and Axle.— The power multiplied by the radius of the wheel is equal to the weight multi- 
 plied by the radius of the axle. 
 
 As the radius of the wheel is to the radius of the axle, so is the effect to the power. 
 
 When a series of wheels and axles act upon each other, either by belts or teeth, the weight or velocity 
 will be to the power or unity as the product of the radii, or circumferences of the wheels, to the product 
 of the radii, or circumferences of the axles. 
 
 Example. — If the radii of a series of wheels are 9, 6, 9, 10, and 12, and their pinions have each a 
 radius of 6 inches, and the weight applied be 10 lbs., what weight will it raise ? 
 
 10X9X6X9X10X12 ... 
 
 = 75 lbs. weight. 
 
 6X6X6X6X6 ° 
 
 Or, if the 1st wheel make 10 revolutions, the last will make 75 in the same time. 
 
 To find the power of cranes, &c. 
 
 Rule. — Divide the product of the driven teeth by the product of the drivers, and the quotient is the 
 relative velocity, which, multiplied by the length of the winch and the force in lbs. and divided by the 
 radius of the barrel, will give the weight that can be raised. 
 
 Example. — A force of 18 lbs. is applied to the winch of a crane, the length being 8 inches ; the pinion 
 Unving 6, the wheel 72 teeth, and the barrel 6 inches diameter. 
 
 -^ = 12X8X18 = 1728-1-3 = 576 lbs. weight. 
 
 Let w represent length of winch, 
 r “ radius of barrel, 
 
 P “ force applied, 
 
 v “ velocity, 
 
 W “ weight raised. 
 
 i^=W. 
 
 r 
 
 W r = v w P. 
 — = P. 
 
 V w 
 
 Example . — A weight of 94 tons is to be raised 360 feet in 15 minutes, by a force the velocity cl 
 which is 220 feet per minute ; what is the power required ? 
 
 = 24 feet per minute. 
 
 15 1 
 
 24X94 
 
 = 10'2542 tons. 
 
 220 
 
 In a wheel and axle, where the axle has two diameters, the condition of equilibrium is 
 
 W : P :: R : i(r — r'); 
 or, P X R == W X i (r — r'); 
 
 that is, the weight is to the power as the lever by which the power works, is to half the difference of 
 the radii of the axle ; 
 
 R representing radius of wheel, 
 
 r “ radius of large axle, 
 
 r' “ radius of less axle. 
 
 Inclined Plane. — Rule . — As the length of the plane is to its height, so is the weight to the power. 
 
MECHANICAL POWERS. 
 
 369 
 
 Example . — Required the power necessary to 
 feet high. 
 
 As G : 4 : : 
 
 raise 1000 lbs. up an inclined plane 6 feet long and 4 
 1000 : GG6-66 Ans. 
 
 Let W represent weight, 
 
 h “ height of plane, 
 
 l “ length of plane, 
 
 P “ power, 
 
 b “ base of plane, 
 
 p' “ pressure on plane. 
 
 W X h 
 
 h 
 
 Wx6 
 
 To find the length of the base, height, or length of the plane, when any two of them are given. 
 
 Rule. — For the length of the base, subtract the square of the height from the square of the length ol 
 the plane, and the square root of the remainder will be the length of the base. 
 
 For the length of the plane, add the squares of the two other dimensions together, and the square root 
 of their sum will be the length required. 
 
 For the height, subtract the square of the base from the square of the length of the plane, and the 
 square root of the remainder is the height required. 
 
 Example . — The height of an inclined plane is 20 feet, and its length 100 ; what is its base, and the 
 pressure of 1000 lbs. upon the plane ? 
 
 n/' 20 2 — 100 2 = 9 6 00 = 97'98 the base. 
 
 As 100 : 20 : : 1000 : 200 lbs. necessary power to raise the 1000 lbs., and 
 
 loooxopgs 
 
 100 
 
 : 979'8 the 
 
 pressure upon the plane. 
 
 If two bodies on two inclined planes sustain each other by the aid of a cord over a pidley, their weights 
 are directly as the lengths of the planes. 
 
 Example . — -If a body of 50 lbs. weight, upon an inclined plane of 10 feet rise in 100, be sustained by 
 another weight on an opposite plane of 10 feet rise to 90 of an inclination, what is the weight of the 
 latter ? 
 
 As 100 : 90 : : 50 : 45, the answer. 
 
 When a body is supported by two planes, and if the weight be represented by the sine of the angle 
 between the two planes. The pressures upon them are reciprocally as the sines of the inclinations of 
 those planes to the horizon, viz. : 
 
 The weight, ) ( Sine of the angle between the planes. 
 
 The pressure upon one plane, V are as ■< Sine of the angle of one plane. 
 
 The pressure upon the other plane, ) ( Sine of the angle of the other plane. 
 
 Thus, if the angle between the planes was 90°, of one pilane 60°, and the other 80° — since the 
 
 natural sines of 90°, 60°, and 30° are 1, "866, and ’500 — if the body weighed 100 lbs., the pressure upon 
 the plane of 30° would be 86'6 lbs., and upon the plane of 60°, 50 lbs., =the centre of gravity being in 
 the centre of the body. 
 
 When the power does not act parallel to the plane, draw a line perpendicular to the direction of the 
 power's action from the end of the base line, (at the back of the plane,) and the intersection of this line 
 on the length will determine the length and height of the pilane. 
 
 Note . — When the line of direction of the power is parallel to the plane, the power is least. 
 
 The space wliich a body describes upon an inclined plane, when descending on the plane by the force 
 of gravity, is to the space it would freely fall hi the same time, as the height is to the length of the 
 plane ; and the spaces being the same, the times will be inversely in this proportion. 
 
 Example . — If a body be placed upon an inclined plane 300 feet long and 25 feet high, what space 
 will it roll down in one second by the force of gravity alone ? 
 
 As 300 : 25 : : *16'08 : L33 feet, Ans. 
 
 If a body be projected down an inclined plane with a given velocity, then the distance which the body 
 will be from the point of projection in a given time will be tXv -f- — X16087 2 ; but if the body be pro- 
 jected upward, then the distance of the body from the point of projection will be tXv — - X 16'08 1‘. 
 
 The force which accelerates a body down an inclined plane is that fractional part of the force of 
 gravity which is represented by the height of the plane divided by its length. 
 
 Let h represent the height of the plane, l its length, t the time in seconds, s the space which a body 
 
 will move through in a given time, v the velocity, and i the angle of inclination ^sin. i — j^. 
 
 Iv 2 
 
 16’08 hf tv 
 
 '■ ; , or — , or -, 
 
 l ’ 2 64-8 h 
 
 64- 3 sin. i 
 
 or sin. ixl6'08 f 2 . 
 
 32’16 /it ,64'3/ts . . ; 
 
 • , or s/ - , or sin. * X 32T6 t, or V sm. i X 64'3 s. 
 
 Vol. II. — 24 
 
 The distance a body will freely fall in one second by the force of gravity. 
 
370 
 
 MECHANICAL POWERS. 
 
 2s 
 
 t = — , or 
 
 l v 
 
 32-16 K 
 
 h . . 
 
 or sin. i 
 
 or 
 
 l s 
 
 loim'/i 
 
 , or 
 
 32-16 t 
 
 , or 
 
 32-16 sin. 
 
 s v 2 
 
 or • 
 
 16-08 t v 64 3 s 
 
 Or yj ; 
 
 i v 16-08 sin. 4 
 
 The accelerating force on the plane is to the accelerating force of gravity as v 1 is to 64-3 Xs. 
 
 If sin. i = £, it shows that the length of the plane is twice its height, or ^ = 30°. 
 
 If the proportion which the length of the plane bears to the height be given, substitute these pro 
 portions for the length and height in the above rules, and the conclusions will be equally true. 
 
 Wedge.— When two bodies are forced from one another, in a direction parallel to the bach of the wedge. 
 Rule . — As the length of the wedge is to half its back, so is the resistance to the force. 
 
 Example . — The length of the back of a double wedge is 6 inches, and the length of it through the 
 middle 10 inches ; what is the power necessary to separate a substance having a resistance of 150 lbs. ? 
 
 As 10 : 3 : : 150 : 45 lbs., Ans. 
 
 When only one of the bodies is movable. 
 
 Rule . — As the length of the wedge is to its back, so is the resistance to the power. 
 
 Example . — What power, applied to the back of a wedge, will raise a weight of 15,000 lbs., the wedge 
 being 6 inches deep, and 100 long on its base ? 
 
 As 100 : 6 : : 15000 : 900 lbs.,* Ans. 
 
 Note . — As the power of the wedge in practice depends upon the split or rift in the wood to be cleft, 
 or in the body to be raised, the above rules are only theoretical where a rift exists. 
 
 Screw. — As the screw is an inclined plane wound round a cylinder, the length of the plane is found 
 by adding the square of the circumference of the screw to the square of the distance between the 
 threads, and taking the square root of the sum, and the height is the distance between the consecutive 
 threads. 
 
 Rule . — As the length of the inclined plane is to the pitch or height of it, so is the weight to the 
 power. 
 
 When a wheel or capstan is applied to turn the screw, the length of the lever is the radius of the 
 circle described by the handle of the wheel or capstan bar. 
 
 Let P represent power, 
 
 R “ length of lever, 
 
 W “ weight, 
 
 l “ length of the inclined plane, 
 
 p “ pitch of screw or height of plane, 
 
 x “ effect of power at circumference of screw, 
 
 r “ radius of screw. 
 
 Then, by the above rules, 
 
 As l 
 
 p : 
 
 : W 
 
 P, 
 
 P 
 
 W : 
 
 : P 
 
 i, 
 
 l 
 
 W: 
 
 : p 
 
 P, 
 
 r 
 
 R 
 
 : P 
 
 X, 
 
 W 
 
 l : 
 
 : P 
 
 p. 
 
 P 
 
 X 
 
 : r 
 
 R, 
 
 P 
 
 l : 
 
 : P 
 
 ■ w, 
 
 It 
 
 r : 
 
 : x 
 
 P. 
 
 Example . — What is the power requisite to raise a weight of 8000 lbs. by a screw of 12 inches circum 
 ference and 1 inch pitch ? 
 
 12 2 -f- 1 2 = 145, and ^145 = 12 04159. 
 
 Then, 12-0416 : 1 : : 8000 : 664-36 lbs., Ans. 
 
 And if a lever of 30 inches length was added to the screw, 
 
 12 -1- 3-1416 = 3-819 2 + SO = 31-9095, length of lever. 
 
 Then, as 31-9095X2X3-1416 : 12-0416 : : 664-36 : 399 lbs., Ans. 
 
 Or, let C represent the circumference described by the power, and we have 
 
 P : W : : p : C, 
 
 C : p : : W : P, 
 
 P X C =W Xp; 
 
 When a hollow screw revolves upon one of less diameter and pitch, (or the differential screw,) the 
 effect is the same as that of a single screw, in which the distance between the threads is equal to the 
 difference of the distances between the threads of the two screws. 
 
 If one screw has 20 threads in an inch pitch, and the other 21, the power is to the weight as the 
 difference between Ar and »Y> or 4"3 o' = 1 to 420. 
 
 In a complex machine, composed of the screw, and wheel, and axle, the relation between the weight 
 »nd power is thus : 
 
 Let x represent the effect of the power on the wheel, 
 
 R “ the radius of the wheel, 
 
 p “ the pitch of the screw, 
 
 r “ the radius of the axle, 
 
 C “ the circumference described by the power. 
 
 * Thi9 is exclusive of friction, which in this machine is very great. 
 
MECHANICAL POWERS. 
 
 371 
 
 Then, by the properties of the screw, 
 and of the wheel and axle, 
 
 PXC = .r Xp; 
 iXR=Wxr. 
 
 Hence we have 
 
 PXCXrXR = J'Xj)XWXr. 
 
 Omitting the common multiplier, x, 
 
 PXCXR = W XpXr; 
 or P : W : : pXr : CxR, 
 andpXr : CxR : : P : W. 
 
 Example . — What weight can be raised with a power of 10 lbs. applied to a crank 32 inches long, 
 turning an endless screw of 3£ inches diameter and one inch pitch, applied to a wheel and axle of 20 
 and 5 inches in diameter respectively ? 
 
 Circumference of 64 = 201. 
 
 1 : 201 : : 10 : 2010. 
 
 Radii of wheel and axle, 10 and 2 5. 
 
 2-5 : 10 : : 2010 : 8040 lbs., Ans. 
 
 or 2-5X1 : 201 X 10 : : 10 : 8040. 
 
 And when a series of wheels and axles act upon each other, the weight will be to the power as the 
 continued product of the radii of the wheels to the continued product of the radii of the axles ; 
 
 thus, W : P : : R 3 : r 3 ; 
 or, r 3 : R 3 : : P : W, 
 
 there being three wheels and axles of the same proportion to each other. 
 
 Example . — If an endless screw, with a pitch of half an inch, and a handle of 20 inches radius, bo 
 turned with a power of 150 lbs., and geered to a toothed wheel, the pinion of which turns another wheel, 
 and the pinion on the second wheel turns a third wheel, to the pinion or barrel of which is hung a 
 weight, it is required to know what weight can be sustained in that position, the diameter of the wheels 
 being 18, and the pinions 2 inches ? 
 
 pXr* : CXR 3 : : P : AV; 
 
 or -5X1 3 : 125-6X9 3 : : 150; 
 
 which, when extended, gives 
 
 •5 : 91562-4 : : 150 : 21468720 lbs., Ans. 
 
 Note . — The diameter of a screw is not a necessary element in determining the weight it will support, 
 when the point at which the power is applied is given. 
 
 Pullet. — When only one cord or rope is used. 
 
 Rule . — Divide the weight to be raised by the number of parts of the rope engaged in supporting the 
 lower or movable block. 
 
 Example . — What power is required to raise 600 lbs., when the lower block contains six sheaves and 
 the end of the rope is fastened to the upper block, and what power when fastened to the lower block ? 
 
 600 
 
 = 50 lbs., 1 st Ans. 
 
 6X2 
 
 — — =46-15 lbs., 2d Ans. 
 
 6 X 2-|-l 
 
 or W = n X P, 
 
 n signifying the number of parts of the rope which sustain the lower block. 
 
 When more than one rope is used. 
 
 In a Spanish burton, where there are two ropes, two movable pulleys, and one fixed and one sta- 
 tionary pulley, with the ends of one rope fastened to the support and upper movable pulley, and the 
 ends of the other fastened to the lower block and the power, the weight is to the power as 5 to 1. 
 
 And in one where the ends of one rope are fastened to the support and the power, and the ends of 
 the other to the lower and upper blocks, the weight is to the power as 4 to 1. 
 
 In a system of pulleys, with any number of ropes, the ends being fastened to the support, 
 
 AV = 2" X P, 
 
 n expressing the number of ropes. 
 
 Example . — What weight will a power of 1 lb. sustain in a system of 4 movable pulleys and 4 ropes ? 
 
 1X2X2X2X2 = 16 lbs., Ans. 
 
 When fixed pulleys are used in the place of hooks, to attach the ends of the rope to the support, 
 
 W = 3"xP. 
 
 Example . — What weight will a power of 5 lbs. sustain with 4 movable and 4 fixed pulleys, and 4 ropes ? 
 5X3X3X3X3 = 405 lbs., Ans. 
 
 When the ends of the rope, or the fixed pulleys, are fastened to the weight, 
 
 W = (2»— 1)XP, 
 and W =(3" — 1)XP, 
 which would give, in the above examples, 
 
 1X2X2X2X2= 16 — 1= 15 lbs., 
 
 5X3X3X3X3=405 — 1=404 lbs. 
 
372 
 
 MECHANICAL POWER OF STEAM. 
 
 MECHANICAL POWER OF STEAM. Under the head of Crank, in the first volume of this Dic- 
 tionary, reference is made to this article for an elucidation of the theory of its movement, as also for 
 an explanation of the mechanical laws of steam. These last should be sought under their proper head 
 “ Steam,” while the theory of the crank will be explained in this place, as reference has been made to 
 it under this head. 
 
 If we consider the rotatory engine with revolving piston apart from the practical objections against 
 its application, it is a perfect engine, and is capable of giving out all the effect of the steam. An im- 
 pression has, however, widely prevailed that this is not the case with the common reciprocating engine 
 with its connecting-rod and crank. Several scientific writers on the steam-engine have pointed out the 
 error of this conviction, so that all the better-informed class of engineers are well aware that the crank, 
 like all other pieces of machinery, fully transmits the power which is communicated to it. There are 
 others, however, who cannot understand this : they cannot set out from the great fundamental principle 
 of virtual velocities, and satisfy themselves with asserting the truth as a simple and inevitable deduc- 
 tion from it. They are continually asking the question, “ How is it that, in the common crank, we are 
 able to show that, at two given points in its revolution, the position is such that an infinite power would 
 produce no effect at all ; that there are only two positions in which the force and effect are equal ; and 
 that, at every other position, the effective pressure given out by the connecting-rod to the crank is less 
 than the original pressure of the steam on the piston — the remainder of the pressure of the steam pro- 
 ducing only a useless pressure on the cranks — how then can the crank be conceived to transmit the 
 whole mechanical effect of the steam ?” In the present remarks we intend to give an answer to this 
 question. We intend to examine, at considerable length, the action of the crank, and to show that the 
 great fact upon which the whole science of mechanics has rested ever since the time of Galileo, still 
 obtains in all its generality in this particular case. For the purpose of clearly elucidating the subject 
 we intend to consider it at first in a very simple and practical manner, and then to examine it in a more 
 theoretical point of view. 
 
 Before proceeding further it is necessary to have a clear conception of the meaning of the term 
 “ power.” It is obvious that it must be different from the term “ force” or “ pressure for, if its mean- 
 ing were the same, it would be absurd to say that the crank always transmits the whole “ power,” since 
 in some position^ it does not transmit any of the pressure of the steam at all. The term “ power,” as 
 generally used by writers on the steam-engine, means the mechanical power of the steam, or its me- 
 chanical effect. In estimating the mechanical effect we have to consider two things : 1st, the load or 
 force raised, and 2d, the distance through which it is raised; and the mechanical effects are considered 
 to be equal when the product of these two are equal. For example, suppose two different machines 
 constructed in such a manner that in the one 1 lb. of steam is made to raise 10 tons through 8 feet, and 
 that in the other 1 lb. of steam is made to raise 15 tons through 6 feet; we say that the mechanical 
 effect of the steam is the same in these two machines, because 10X8=15X6. This principle may be 
 expressed in the form of a rule : — “ Mechanical effects are equal when the weights raised are inversely 
 proportional to the distances through which they are raised.” This law is useful for comparing the 
 mechanical effects of different machines ; our purpose, at present, however, is to compare the mechani- 
 cal effects of different parts of the same machine. It will not be difficult so to modify this law as to 
 suit our purposes. When it is different machines that we are comparing, the time for developing the 
 mechanical effects may be different, but in the same machine the time must necessarily be the same. 
 From this equality of time we infer that the spaces through which the load is moved are directly pro- 
 portional to the uniform velocity with which they are described. Hence the law may be expressed as 
 follows: “The mechanical effects of the different parts of the same machine are equal when the 
 weights or pressures raised are inversely proportional to the velocities with which they are raised. ’ 
 The product of a weight or pressure into its velocity is called the “momentum of the weight or pres- 
 sure.” After this definition, our rule may be expressed as follows: “Mechanical effects of the differ- 
 ent parts of the same machine are equal when the momenta are equal.” A dopting the principle that 
 the momentum measures the mechanical effect, or, as it is usually called, the power, it is a recognized 
 principle, proved by all writers on mechanics, that however complicated machinery may be, still, making 
 allowance for the resistances arising from friction, the mechanical effect remains the same. Our inten- 
 tion at present is only to show that it obtains in the particular case 
 of the crank. The crank-pin moves through a greater space than 
 the piston ; and when the piston is moving very slowly the crank- 
 pin is moving very quickly, so that the ultimate effect is the same 
 at every moment. By multiplying the pressure into the velocity, 
 it will be found that the same quantity of steam produces the 
 same amount of power at every part of the stroke. 
 
 Suppose the velocity of the piston to be uniform, then the mo- 
 tion of the extremity of the connecting-rod will be uniform also. 
 
 The extremity of the crank always moves irregularly, but as it 
 moves over a greater space than the extremity of the connecting- 
 rod, its mean velocity must be greater. The proportion is obviously 
 as follows : 
 
 Velocity of piston : mean velocity of extremity of crank : : twice 
 the length of stroke : circumference which the extremity of the 
 crank describes. 
 
 Let l denote the length of stroke, and n the ratio of the circum- 
 ference of a circle to its diameter ; then we have the proportion, 
 
 Velocity of piston : mean velocity of extremity of crank : : 2 
 l : 7t l : : 2 : “, and, therefore, mean velocity of extremity of crank 
 = 7r x velocity of piston — 2. Since the mean velocity of the 
 
MECHANICAL POWER OF STEAM. 
 
 37 
 
 crank is greater than that of the piston, then, according to our law, in order to produce the same mechan- 
 ical effect, the mean effective pressure must be less, and that in the same proportion. We may approxi- 
 mate to the mean effective pressure by calculating it for a great many equidistant positions, and taking 
 the average. Thus let Fig. 2804 represent the circle which the extremity of the crank describes. Di- 
 vide it into 20 equal parts. Suppose the connecting-rod to remain always in a parallel direction, and 
 the constant pressure in it to be 100. The effective pressure at any point P will be 100 sin. POE. 
 From this we have the following table : 
 
 Points in the Figure. 
 
 Pressure in the Direction of Revolution. 
 
 At 0 and at 
 
 20 
 
 100 
 
 X 
 
 sin. 
 
 0° = 
 
 000 
 
 
 1 
 
 19 
 
 100 
 
 X 
 
 sin. 
 
 18° = 
 
 30-90 
 
 
 2 
 
 18 
 
 100 
 
 X 
 
 sin. 
 
 36° = 
 
 58-78 
 
 
 3 
 
 17. 
 
 100 
 
 X 
 
 sin. 
 
 54° = 
 
 80-90 
 
 
 4 
 
 16 
 
 100 
 
 X 
 
 sin. 
 
 72° = 
 
 95-11 
 
 
 5 
 
 15 
 
 100 
 
 X 
 
 sin. 
 
 90° = 
 
 100-00 
 
 
 6 
 
 14 
 
 100 
 
 X 
 
 sin. 
 
 108° = 
 
 95-11 
 
 
 7 
 
 13 
 
 100 
 
 X 
 
 sin. 
 
 126° = 
 
 8090 
 
 
 8 
 
 12 
 
 100 
 
 X 
 
 sin. 
 
 141° = 
 
 58-78 
 
 
 9 
 
 11 
 
 100 
 
 X 
 
 sin. 
 
 162° = 
 
 30-90 
 
 
 10 
 
 10 
 
 100 
 
 X 
 
 sin. 
 
 180° = 
 
 o-oo 
 
 
 
 
 
 Mear 
 
 pressure 6ST1 
 
 
 From this we learn that the mean effective pressure is to the pressure at piston in the proportion of 
 about 63 to 100. This is very nearly the same proportion as 2 to it ; for 110 -f- 03 = 1'6 nearly, and 
 ■n--h 2 = l - 7. Hence we have the proportion, pressure at piston : mean effective pressure at extremity 
 of crank : : mean velocity of extremity of crank : velocity of piston. This shows, according to our law, 
 that the mechanical effect of the pressure at the piston is wholly transmitted to the crank. 
 
 We have said not only that the mechanical effect is the same ultimately, but that it is the same 
 momentarily ; that is to say, that the product of the effective force at any point, and the velocity at 
 that point, is constantly equal to the product of the pressure at the piston, and its velocity at the cor- 
 responding position. It is more difficult to illustrate this in the same manner, on account of the diffi- 
 culty of calculating the relative velocity of the crank and piston. It is very easy to show, however, 
 that at what is called the “position of the centres” no loss of power can really take place. This hap- 
 pens for this very plain reason, that there is no power exerted at that time. It ought to be remem- 
 bered that at that time the communication which supplies the steam from the boiler is cut off. The 
 steam on one side having done its work, only waits to be released from its chamber, and escapes at the 
 opening of the eduction valve, and at the same instant is in the act of being permitted to enter on the 
 opposite side for reversing the motion. Hence at these points all application of force has ceased, and 
 arrangements are making for reversing the motion ; besides which, when the engine is on the centre, 
 the piston has not any motion. 
 
 With regard to the remaining points of the circle, at which it is said power is lost, the velocity im- 
 parted to the crank is always an exact equivalent for the force which is apparently lost. At present 
 we wish only to illustrate this fact, for its rigid demonstration requires rather abstract considerations. 
 The following table presents the results of the calculations of the power and velocity. The numbers 
 I, 2, &c., refer to Fig. 2804. 
 
 Position of Crank. 
 
 Pressure in Direction of 
 Revolution. 
 
 Velocity of Crank divided 
 by Velocity of Piston. 
 
 At 0 and at 20 
 
 o-oo 
 
 Infinite 
 
 1 
 
 19 
 
 30-90 
 
 3-236 
 
 2 
 
 18 
 
 58-78 
 
 1-701 
 
 3 
 
 17 
 
 80-90 
 
 1-236 
 
 4 
 
 16 
 
 95-11 
 
 1-051 
 
 5 
 
 15 
 
 10000 
 
 1-0OC 
 
 6 
 
 14 
 
 95-11 
 
 1-051 
 
 7 
 
 13 
 
 80-90 
 
 1-236 
 
 8 
 
 12 
 
 58-78 
 
 1-701 
 
 9 
 
 11 
 
 30-90 
 
 3-236 
 
 10 
 
 10 
 
 0-00 
 
 Infinite 
 
 These are obtained on the supposition that the force on the piston and its velocity are constant, and 
 »lso that the connecting-rod keeps always in a parallel direction. Neither of these suppositions is ex- 
 actly true in practice. The same law holds, although the pressure on the piston is variable, and also its 
 velocity, and although the connecting-rod takes different inclinations. It will be observed from our table 
 that the smaller the effective pressure in the direction of the revolution, the greater the relative velocity 
 The rigid demonstration of these facts requires for their proper exhibition the differential calculus 
 tvhich in this work would be out of place. 
 
374 
 
 MENSURATION. 
 
 MEERSCHAUM. This form of silicate of magnesia is employed in manufacturing the celebrated 
 tobacco-pipes known under this name, and its composition is as follows, differing but little from steatite 
 or soapstone ; but, unlike the latter, may be artificially produced : 
 
 Madrid. Natoiia. 
 
 53-80 42-00 
 
 23-80 30-50 
 
 23-80 2-30 
 
 { K} «• 
 
 20-00 23-00 
 
 100-05 98-80 99-30 
 
 It is found in the native state on the shores of the inland seas of Europe. That found in Morocco 
 contains, in addition to the above ingredients, -52 of potash. It is. light and soft, and is employed in the 
 Turkish dominions as fuller’s earth. In Germany it is extensively used in the manufacture of tobacco- 
 pipes, which are prepared for sale by being soaked first in tallow, then in wax, and finally by being 
 polished with shave-grass. Imitation meerschaum pipes are sold in large quantities, and the greatest 
 caution is necessary to guard against deception. To the connoisseur, the best criterion is the beautiful 
 brown color which the genuine meerschaum assumes after being smoked some time. 
 
 MENSURATION — Of Surfaces. To find the area of a four-sided figure. — Rule. — M ultiply the 
 length by the breadth or perpendicular height ; the product will be the area. 
 
 To find the area of a triangle. — Rule. — M ultiply the length of one of the sides, by a perpendicular 
 falling upon it from the opposite angle; half the product will be the area. 
 
 To find the length of one side of a right-angled triangle , when the lengths of the other two sides are 
 given. — Rule 1 . — To find the hypothenuse, add together the squares of the two legs, and extract the 
 square root of that sum. 
 
 Rule 2. — To find one of the legs, subtract the square of the leg, of which the length is known, from 
 the square of the hypothenuse, and the square root of the difference will be the answer. 
 
 To find the area of a regular polygon. — Rule. — M ultiply the length of a perpendicular, drawn from 
 twe centre to one of the sides, (or the radius of its inscribed circle,) by the length of one side, and this 
 product again by the number of sides ; and half the product will be the area of the polygon. 
 
 To find the area of a trapezium. — Rule 1. — Draw a diagonal line to divide the trapezium into two 
 triangles ; find the areas of these triangles separately, and add them together. 
 
 Rule 2. — Divide the trapezium into two triangles, by a diagonal, and let two perpendiculars fall on 
 the diagonal from the opposite angles ; then, the sum of these perpendiculars multiplied by the diagonal, 
 and divided by 2, will be the area of the trapezium. 
 
 To find the area of a trapezoid. — Rule 1. — Multiply the sum of the two parallel sides by the perpen- 
 dicular distance between them, and half the product will be the area. 
 
 Rule 2. — Draw a diagonal, to divide the trapezoid into two triangles ; find the areas of those triangles 
 separately, and add them together. 
 
 To find the area of an irregular polygon. — Rule. — D raw diagonals, to divide the figure into tra- 
 peziums and triangles ; find the area of each separately, by either of the rules before given for that 
 purpose ; and the sum of the whole will be the area of the figure. 
 
 To find the area of a long irregular figure. — Rule. — T ake the breadths in several places, and at equal 
 distances from each other ; add all the breadths together, and divide the sum by this number, for the 
 mean breadth ; then multiply the mean breadth by the length of the figure, and the product will be the 
 area. 
 
 To find the circumference of a circle when the diameter is given ; or the diameter when the circumfer- 
 ence is given. — Rule 1. — Multiply the diameter by 3-1416, and the product will le the circumference; 
 or divide the circumference by 3-1416, and the quotient will be the diameter. 
 
 Rule 2. — As 7 is to 22, so is the diameter to the circumference ; 
 
 As 22 is to 7, so is the circumference to the diameter. 
 
 Rule 3. — As 113 is to 355, so is the diameter to the circumference; 
 
 As 355 is to 113, so is the circumference to the diameter. 
 
 To find the area of a circle.— Rule 1. — Multiply the square of the diameter by -7854 ; or the square 
 of the circumference by "07958; the product, in either case, will be the area. 
 
 Rule 2. — Multiply the circumference by the diameter, and divide the product by 4. 
 
 Rule 3. — As 14 i% to 11, so is the square of the diameter to the area ; 
 
 Or as 88 is to 7, so is the square of the circumference to the area. 
 
 To find the length of any arc of a circle. — Rule 1. — From 8 times the chord of half the arc, subtract 
 the chord of the whole arc ; one-third of the remainder will be the length of the arc, nearly. 
 
 Rule 2. — As 180 is to the number of degrees in the arc; 
 
 So is 3-1416 times the radius to its length. 
 
 Or, as 3 is to the number of degrees in the arc ; 
 
 So is -05236 times the radius to its length. 
 
 To find the area of d sector of a circle. — Rule 1. — Multiply the length of the arc by half the length of 
 the radius ; the product will be the area. 
 
 Rule 2. — As 360 degrees is to the number of degrees in the arc of the sector ; so is the area of the 
 circle to the area of the sector. 
 
 To find the area of a segment of a circle. — Rule 1. — To the chord of the whole arc, add the chord oi 
 naif the arc and one-third of it more. Then multiply the sum by the versed sine, or height of the seg- 
 ment, and four-tenths of the product will be the area of the segment. 
 
 
 Levant. 
 
 Silica 
 
 60-87 
 
 Magnesia 
 
 27-80 
 
 Lime 
 
 27-80 
 
 Alumina 
 
 ) 
 
 Oxide of iron 
 
 ' 1 -009 
 
 Water 
 
 11-29 
 
MENSURATION. 
 
 375 
 
 Rule 2. — Divide the height, or versed sine, by the diameter of the circle, and find the quotient in the 
 column of versed sines, in the table of areas of segments. 
 
 Then take out the corresponding area in the next column on the right-hand, and multiply it by the 
 square of the diameter, for the answer. 
 
 To find the area of a circular zone. — Rule 1. — When the zone is less than a semicircle, to the area of 
 the trapezoid, formed by connecting the extremities of the zone by straight lines, add the area of the 
 circular segments beyond those lines ; the sum is the area of the zone. 
 
 Rule 2. — When the zone is greater than a semicircle, to the area of the parallelogram, formed in like 
 manner as above, add the area of the circular segments, at its extremities ; the sum is the area of the 
 zone. 
 
 To find the area of a circular ring, or space, included between two concentric circles . — Rule. — Find the 
 areas of the two circles separately ; then the difference between them will be the area of the ring. 
 
 To find the ofrcumference of an ellipse.-— Rule. — Square the two axes, and multiply the square root 
 of half that sum by 3T416 ; the product will be the circumference, nearly. 
 
 To find the area of an ellipse . — Rule. — Multiply the transverse diameter by the conjugate, and the 
 product by "7854. 
 
 To find the area of an elliptic segment. — Rule. — Divide the height of the segment by the axi9 of 
 which it is a part, and find, in the table of segments of circles, a circular segment having the same 
 versed sine as this quotient. Then, multiply the segment thus found and the two axes of the ellipse 
 continually together, and the product will give the area required. 
 
 When the transverse, the conjugate, and the abscissa! are given , to find the ordinate. — Rule. — Multiply 
 the abscissae into each other, and extract the square root of the product ; this will give the mean 
 between them. Then, as the transverse diameter is to the conjugate diameter, so is the mean to the 
 ordinate required. 
 
 When the transverse, the conjugate, and the ordinate are given, to find the abscissce . — Rule. — From 
 the square of half the conjugate, take the square of the ordinate, and extract the square root of the 
 remainder. 
 
 Then, as the conjugate diameter is to the transverse, so is that square root to half the difference of 
 the two absciss®. 
 
 Add this half difference to half the transverse, for the greater abscissa; and subtract it for the less. 
 
 When the transverse, the ordinate, and the two abscissce are given, to find the conjugate . — Rule. — As 
 the square root of the product of the two absciss® is to the ordinate, so is the transverse diameter to 
 the conjugate. 
 
 Note . — In the same manner the transverse diameter may be found from the conjugate, using the two 
 absciss® of the conjugate, and their ordinate perpendicular to the conjugate. 
 
 When the conjugate, the ordinate, and the abscissce are given, to find the transverse diameter. — Rule. — 
 From the square of half the conjugate subtract the square of the ordinate, and extract the root of the 
 remainder. Add this root to the half conjugate if the less abscissa be given ; but subtract it when the 
 greater abscissa is given. 
 
 Then, as the square of the ordinate is to the rectangle of the abscissa and conjugate, so is the reserved 
 sum, or difference, to the transverse diameter. 
 
 To find the area of a parabola . — Rule. — Multiply the base by the height, and two-thirds of the pro- 
 duct will be the area. 
 
 To find the area of a frustum of a parabola. — Rule. — Multiply the difference of the cubes of the two 
 ends of the frustum by twice its altitude, and divide the product by thrice the difference of their squares. 
 
 To find the abscissa or ordinate of the parabola. — Rule. — The absciss® are to each other as the 
 squares of their ordinates ; that is, as any abscissa is to the square of its ordinate, so is any other 
 abscissa to the square of its ordinate. 
 
 Or, as the square root of any abscissa is to its ordinate, so is the square root of another abscissa to its 
 ordinate. 
 
 To find the length of a parabolic curve, cut off by a double ordinate. — Rule. — To the square root of 
 the ordinate, add four-thirds of the square of the abscissa ; the square root of that sum, multiplied by 2, 
 will give the length of the curve, nearly. 
 
 To find the area of a hyperbola . — Rule. — -To five-sevenths of the abscissa, add the transverse diame- 
 ter ; multiply the sum by the abscissa, and extract the square root of the product. Then, multiply the 
 transverse diameter by the abscissa, and extract the square root of that product. 
 
 Then, to 21 times the first root add 4 times the second root ; multiply the sum by double the product 
 of the conjugate and abscissa, and divide by 75 times the transverse; this will give the area, nearly. 
 
 To find the length of a hyperbolic curve. — Rule. — To 21 times the square of the conjugate add 9 times 
 the square of the transverse; also, to 21 times the square of the conjugate add 19 times the square of 
 the transverse, and multiply each of these sums by the abscissa. 
 
 To each of the two products add 15 times the product of the transverse and square of the conjugate. 
 
 Then, as the less sum is to the greater, so is the ordinate to the length of the curve, nearly. 
 
 When the transverse, the conjugate, and the abscissce are given, to find the ordinate . — Rule. — As the 
 transverse diameter is to the conjugate, so is the square root of the product of the two absciss® to the 
 ordinate required. 
 
 Note . — In the hyperbola, the less abscissa added to the axis gives the greater : and the greater 
 abscissa subtracted from the axis, gives the less. 
 
 When the transverse and conjugate diameters, and the ordinate, are given, to find the abscissae. — Rule. — • 
 To the square of half the conjugate add the square of the ordinate, and extract the square root of that 
 sum. 
 
 Then, as the conjugate diameter is to the transverse, so is the square root +o half the sum of (he 
 absciss®. 
 
376 
 
 MENSURATION. 
 
 To this half sum add half the transverse diameter for the greater abscissa, and subtract it fol 
 the less. 
 
 When the transverse diameter , ordinate , and abscissa;, are given , to find the conjugate. — Rule. — A s the 
 square root of the product of the two abscissas is to the ordiuate, so is the transverse diameter to the 
 conjugate. 
 
 When the conjugate diameter, the ordinate, and the two abscissa:, are given, to find the transverse 
 diameter. — Rule. — To the square of half the conjugate add the square of the ordinate, and extract the 
 square root of that sum. 
 
 To this root add the half conjugate when the less abscissa is used ; and subtract it when the greater 
 abscissa is used ; reserving the sum or difference. 
 
 Then, as the square of the ordinate is to the product of the absciss® and conjugate, so is the reserved 
 sum, or difference, to the transverse. 
 
 Mensuration of Solids. — To find the solidity of a cube. — Rule. — Multiply the side of the cube by 
 itself, and that product again by the side ; the last product will be the solidity of the given cube. 
 
 To find the solidity of a parallelopipedon. — Rule. — Multiply the length, breadth, and depth or alti- 
 tude, continually together, or, in other words, multiply the length by the breadth, and that product by 
 the depth or altitude, and this will give the required solidity. 
 
 To find the solidity of cylinders and prisms . — Rule. — Multiply the area of the base by the height of the 
 cylinder or prism, and the product will give the solid content. 
 
 To find the convex surface of a cylinder. — Rule. — Multiply the circumference by the length of the 
 cylinder ; the product will be the convex surface required. 
 
 lb find the convex surface of a right cone, or pyramid . — Rule. — Multiply the perimeter, or circum- 
 ference of the base, by the slant height, or length of the side of the cone, and half the product will be 
 the surface. 
 
 To find the convex surface of a frustum of a right cone, or pyramid. — Rule. — Multiply the sum of the 
 perimeters of the two ends by the slant height or side of the frustum, and half the product will be the 
 surface required. 
 
 To find the solidity of a cone, or pyramid. — Rule. — Multiply the area of the base by the perpendicular 
 height, and one-third of the product will be the content. 
 
 To find the solidity of the frustum of a cone. — Rule. — Divide the difference of the cubes of the diam- 
 eters of the two ends by the difference of the diameters ; this quotient multiplied by ‘7854 and again by 
 one-third of the height, will give the solidity. 
 
 To find the solidity of the frustum of a pyramid . — Rule. — Add to the areas of the two ends of the 
 frustum the square root of their product, and this sum, multiplied by one-third of the height, will give 
 the solidity. 
 
 To find the solidity of a wedge . — Rule.— T o the length of the edge of the wedge add twice the length 
 of the back ; multiply this sum by the height of the wedge, and then by the breadth of the back ; one- 
 sixth of the product will be the solid content. 
 
 To find the solidity of a prismoid. — Rule. — Add into one sum the areas of the two ends and four 
 times the middle section, parallel to them ; then, this sum multiplied by one-sixth of the height, will 
 give the content. 
 
 Note . — The length of the middle section is equal to half the sum of the lengths of the two ends ; and 
 its breadth is equal to half the sum of the breadths of the two ends. 
 
 To find the convex surface of a sphere, or globe. — Rule. — Multiply the diameter of the sphere by its 
 circumference. 
 
 Or, multiply 3T416 by the square of the diameter; the product will be the convex surface required. 
 
 Note. — The convex surface of any zone or segment may be found, in like manner, by multiplying its 
 height by the whole circumference of the sphere. 
 
 To find the solidity of a sphere or globe. — Rule. — Multiply the cube of the axis by '5236 ; the product 
 will be the solidity. 
 
 To find the solidity of a spherical segment . — Rule. — To three times the square of the radius of its 
 base add the square of its height; then, multiply the sum by the height, and the product by '5236. 
 
 To find the solidity of a spherical zone or frustum . — Rule.— T o the sum of the squares of the radius 
 of each end, add one-third of the square of the height of the zone ; this sum, multiplied by the said 
 height, and the product by T5708, will give the solidity. 
 
 To find the solidity of a spheroid. — Rule. — Multiply the square of the revolving axis by the fixed or 
 shorter axis; the product, multiplied by '5236, will give the content. 
 
 To find the solidity of a segment of a spheroid . — Rule 1. — When the base is circular or parallel to the 
 revolving axis, multiply the fixed axis by 3, the height of the segment by 2, and subtract the one product 
 from the other ; then multiply the remainder by the square of the height of the segment, and the pro- 
 duct by '5236. 
 
 Then, as the square of the fixed axis is to the square of the revolving axis, so is the last product to 
 the content of the segment. 
 
 Rule 2. — When the base is perpendicular to the revolving axis, multiply the revolving axis by 3, and 
 the height of the segment by 2, and subtract the one from the other ; then, multiply the remainder by 
 the square of the height of the segment, and the product by '5236. 
 
 Then, as the revolving axis is to the fixed axis, so is the last product to the content. 
 
 To find the solidity of the middle frustum of a spheroid. — Rule 1. — When the ends are crrcuiar, or 
 parallel to the revolving axis, to twice the square of the revolving axis, add the square of the diameter 
 of either end; then, multiply this sum by the length of the frustum, and the product again by '2618; 
 this will give the solidity. 
 
 Rule 2. — When the ends are elliptical, or perpendicular to the revolving axis, to twice the product ol 
 .lie transverse and conjugate diameters of the middle section, add the product of the transverse and 
 
METALS AND ALLOYS. 
 
 377 
 
 conjugate of either end ; multiply this sum by the length of the frustum, and the product by '2618 ; this 
 will give the solidity. 
 
 To find the surface of a circular spindle. — Rule. — Multiply the length of the spindle by the radius of 
 the revolving arc. Multiply also the said arc by the central distance, or distance between the centre oi 
 the spindle and centre of the revolving arc. Subtract this last product from the former ; double the 
 remainder; multiply it by 3-1416, and the product will give the surface of the spindle. 
 
 Note. — The same rule will serve for any segment, or zone, cut off perpendicularly to the chord of the 
 revolving arc ; but, in this case, the particular length of the part, and the part of the arc which describes 
 it, must be used, instead of the whole length and whole arc. 
 
 To find the solidity of a circular spindle. — Rule. — Multiply the central distance, as above, by half the 
 area of the revolving segment. Subtract the product from one-third of the cube of half the length ol 
 the spindle. Then, multiply the remainder by 12-5664, or 4 times 3-1416, and the product will be the 
 solidity required. 
 
 To find the solidity of the frustum , or zone , of a circular spindle. — Rule. — From the square of half 
 the length of the whole spindle, take one-third of the square of half the length of the frustum, and mul- 
 tiply the remainder by the said half-length of the frustum. Multiply the central distance by the 
 revolving area, which generates the frustum. Subtract the last product from the former ; and the 
 remainder, multiplied by 6‘2832, or twice 3-1416, will give the content. 
 
 To find the solidity of an elliptic spindle. — Rule. — To the square of the greatest diameter, add the 
 square of twice the diameter at one-fourth of its length ; multiply the sum by the length, and the pro- 
 duct by '1309, and it will give the solidity, very nearly. 
 
 To find the solidity of a frustum or segment of an elliptic spindle. — Rule. — Proceed, as in the last 
 rule, for this, or any other solid, formed by the revolution of a conic section about an axis, namely : 
 
 Add together the squares of the greatest and least diameters, and the square of double the diameter 
 in the middle between the two; multiply the sum by the length, and the product by -1309, and it will 
 give the solidity. 
 
 Note. — For all such solids this rule is exact when the body is formed by the conic section, or a part 
 of it, revolving about the axis of the section ; and it will always be very near the truth, when the figure 
 revolves about another line. 
 
 To find the solidity of a parabolic conoid. — Rule. — Multiply the square of the diameter of the base 
 by the altitude, and the product by -3927. 
 
 To find the solidity of a frustum of a paraboloid. — -Rule. — Multiply the sum of the squares of the 
 diameters of the two ends by the height of the frustum, and the product by -3927. 
 
 To find the solidity of a parabolic spindle. — Rule. — Multiply the square of the middle diameter by 
 the length of the spindle, and the product by '41888, (which is eight-fifteenths of -7854,) and it will give 
 the content. 
 
 To find the solidity of the middle frustum of a parabolic spindle. — Rule. — Add together 8 times the 
 square of the greatest diameter, 3 times the square of the least diameter, and 4 times the product of 
 these two diameters; multiply the sum by the length, and the product by '05236, (which is -J of 
 3-1416 ;) this will give the solidity. 
 
 To find the convex surface of a cylindrical ring. — Rule. — To the thickness of the ring add the inner 
 diameter ; multiply this sum by the thickness, and the product by 9'8696, (which is the square of 
 3-14159,) and it will give the superficies required. 
 
 To find the solidity of a cylindrical ring. — Rule. — To the thickness of the ring add the inner diameter ; 
 then multiply the sum by the square of the thickness, and the product by 2-4674, (which is one-fourth 
 of the square of 3-1416,) and it will give the solidity. 
 
 To find the superficies or solidity of any regular body. — Rule 1. — Multiply the tabular surface by the 
 square of the linear edge, and the product will be the superficies. 
 
 Rule 2. — Multiply the tabular solidity by the cube of the linear edge, and the product will be the 
 solidity. 
 
 Table of the Surfaces and Solidities of the Regular Bodies when the linear edge is 1 . 
 
 No. of Sides. 
 
 Names. 
 
 Surfaces. 
 
 Solidities. 
 
 4 
 
 Tetrahedron 
 
 1-73205 
 
 0-11785 
 
 6 
 
 Hexahedron 
 
 6-00000 
 
 1-00000 
 
 8 
 
 Octahedron 
 
 3-46410 
 
 0-47140 
 
 12 
 
 Dodecahedron 
 
 20-64573 
 
 7-66312 
 
 20 
 
 Icosahedron 
 
 8-66025 
 
 2-18169 
 
 METALS AND ALLOYS, employed in the mechanical and useful arts. Metals are elementary 
 oodies, being all capable of combining with oxygen, and many of them, during this combination, exhibit 
 the phenomena of combustion. Formerly only seven metals were known, but modern discoveries have 
 added to the number greatly. Metals are distinguished by their great specific gravity, considerable 
 tenacity and hardness, opacity, and property of reflecting the greater part of the light which fells on 
 their surface, giving rise to what is denominated the metallic lustre or brilliancy. Opacity is another 
 leading property of metals ; even when beat to the greatest possible thinness, "they transmit scarcely 
 any light; from the union of the two qualities density and opacity, arises that of lustre. By their 
 opacity and the denseness of their texture, they reflect the greatest part of the light that falls on their 
 surface. From their density they are susceptible of a fine polish, by which their lustre is increased 
 
378 
 
 METALS AND ALLOYS. 
 
 Tenacity distinguishes a number of the metals, and is not possessed in any great degree by othel 
 bodies ; hence arises their malleability and ductility. Some of the metals are neither malleable not 
 ductile. Both these qualities are greater in combinations of the metals than in the individual metals. 
 Metals are the best conductors of caloric ; their expansibilities are various, and are probably nearly in 
 the order of their fusibilities. Mercury melts at so low a temperature, that it can be obtained in the 
 solid state only at a very low temperature ; others, as platina, can scarcely be melted by the most in- 
 tense heat which we can excite. Metals may be volatilized ; at the degree of 600 quicksilver may be 
 volatilized, and zinc and arsenic at a temperature not very remote from this. Metals are the best con- 
 ductors of electricity. 
 
 Table of the Properties of the Metals. 
 
 Name. 
 
 When dis- 
 covered. 
 
 By whom. 
 
 Color. 
 
 Specific 
 
 gravity. 
 
 fcf~ 
 
 o 
 
 o. 
 
 Scale of 
 ductility. 
 
 Scale of 
 malleability. 
 
 Tenacity. 
 
 Ratio of 
 hardness. 
 
 Gold 1 
 
 
 
 Pure yellow. 
 
 19-257 
 
 5237 
 
 1 
 
 i 
 
 08-210 
 
 8 
 
 Silver 
 
 
 
 
 White. 
 
 10-474 
 
 3077 
 
 2 
 
 2 
 
 85 062 
 
 6 
 
 Iron ^. . 
 
 
 Known from 
 
 
 Blue-gray. 
 
 7-788 
 
 17077 
 
 4 
 
 8 
 
 209-659 
 
 3 
 
 Copper 
 
 
 the earliest 
 
 
 Red. 
 
 8-895 
 
 4587 
 
 5 
 
 3 
 
 157-399 
 
 5 
 
 Mercury 
 
 
 ages. 
 
 
 White. 
 
 13-508 
 
 30 
 
 
 
 
 None. 
 
 head 
 
 
 
 
 Blue. 
 
 1 1-352 
 
 594 
 
 8 
 
 0 
 
 
 14 
 
 Tin 
 
 
 
 
 White. 
 
 7-291 
 
 442 
 
 7 
 
 4 
 
 24-200 
 
 12 
 
 Zinc 
 
 1.141 
 
 Paracelsus. 
 
 Bluish-white. 
 
 0001 
 
 700 
 
 6 
 
 7 
 
 12-720 
 
 9 
 
 Bismuth 
 
 1.TJ0 
 
 Agricola. 
 
 Yellowish-white. 
 
 9-822 
 
 470 
 
 
 
 
 7 
 
 Antimony 
 
 XVth cent. 
 
 B. Valent. 
 
 Bluish-white. 
 
 6*702 
 
 932 
 
 
 
 
 10 
 
 Arsenic 
 
 1723 
 
 Brandt. 
 
 Gray. 
 
 8-308 
 
 
 
 
 
 13 
 
 Cobalt 
 
 
 do. 
 
 Gray-white. 
 
 8-538 
 
 10077 
 
 
 
 
 11 
 
 Platinum 
 
 i?4i 
 
 Wood. 
 
 Bluish-white. 
 
 21-500 
 
 G. B. P. 
 
 3 
 
 5 
 
 124-000 
 
 4 
 
 Nickel 
 
 1751 
 
 Cronstedt. 
 
 White. 
 
 8-279 
 
 21877 
 
 9 
 
 9 
 
 
 
 Manganese 
 
 1774 
 
 Scheele. 
 
 Gray- white. 
 
 5*850 
 
 do. 
 
 
 
 
 2 
 
 Tungsten 
 
 1781 
 
 D'EIhuyart. 
 
 
 7*600 
 
 G. B. P. 
 
 
 
 
 i 
 
 Tellurium 
 
 1782 
 
 Muller. 
 
 
 6*115 
 
 
 
 
 
 
 Molybdenum 
 
 do. 
 
 Iljelm. 
 
 Gray. 
 
 7*400 
 
 G. B. P. 
 
 
 
 
 
 Titanium 
 
 1781 
 
 G regor. 
 
 Red. 
 
 
 do. 
 
 
 
 
 
 Uranium 
 
 1789 
 
 Klaproth. 
 
 Gray. 
 
 9-000 
 
 do. 
 
 
 
 
 
 Chromium 
 
 1707 
 
 Vauquelin. 
 
 
 
 do. 
 
 
 
 
 
 Columbium 
 
 1802 
 
 Hatchett. 
 
 
 
 do. 
 
 
 
 
 
 Palladium 
 
 1803 
 
 Wollaston. 
 
 Bluish-white. 
 
 li-300 
 
 
 10 
 
 10 
 
 
 i 
 
 Rhodium 
 
 do. 
 
 do. 
 
 Grayish- white 
 
 
 g. ii. p. 
 
 
 
 
 
 Iridium 
 
 do. 
 
 Descot i Is. 
 
 
 
 
 
 
 
 
 Osmium 
 
 do. 
 
 Tenant. 
 
 Bluish-black. 
 
 
 do. 
 
 
 
 
 
 Cerium 
 
 1804 
 
 Berzelius. 
 
 Gray- white. 
 
 
 do. 
 
 
 
 
 
 Potassium "j 
 
 
 
 do. 
 
 0-805 
 
 130 
 
 
 
 
 100 
 
 Sodium [ 
 
 
 
 do. 
 
 0-972 
 
 194 
 
 
 
 
 100 
 
 Barium 
 
 1807 
 
 Davy. 
 
 
 
 
 
 
 
 
 Strontium j 
 
 
 
 
 
 
 
 
 
 
 Calcium J 
 
 
 
 
 
 
 
 
 
 ... # 
 
 Cadmium 
 
 1818 
 
 Stromeyer. 
 
 White. 
 
 8-004 
 
 
 ii 
 
 ii 
 
 
 
 Lithium 
 
 do. 
 
 Arfvedson. 
 
 
 
 
 
 
 
 
 Silicium 
 
 1824 1 
 
 Berzelius. 
 
 
 
 
 
 
 
 
 Zinconium 
 
 .... j 
 
 do. 
 
 
 
 
 
 
 
 
 Aluminum 
 
 1828 1 
 
 Wohler. 
 
 
 
 
 
 
 
 
 Glucinum 
 
 
 do. 
 
 
 
 
 
 
 
 
 Yttrium 
 
 .... \ 
 
 do. 
 
 
 
 
 
 
 
 
 Thonium 
 
 1829 
 
 Berzelius. 
 
 
 
 
 
 
 
 
 Magnesium 
 
 do. 
 
 Bussy. 
 
 
 
 
 
 
 
 
 Varadium 
 
 1830 
 
 Seftstrom. 
 
 
 
 
 
 
 
 
 Lantanium 
 
 1840 
 
 Mosander. 
 
 
 
 
 
 
 
 I 
 
 A ntimony * is of a silvery white color, brittle and crystalline in its ordinary texture. It fuses at about 
 800°, or at a dull-red heat, and is volatile at a white heat. Its specific gravity is 6-7 1 2. ( Hatchett , 
 
 Phil. Trans. 1803. Brande , 849.) 
 
 Antimony expands on cooling; it is scarcely used alone, except in combination with similar bars of 
 other metals for producing thermo-electricity: but antimony, which in the metallic state is frequently 
 called “regulus,” is generally combined with a large portion of lead, and sometimes with tin, and other 
 metals. See Lead and Tin. 
 
 “Antimony and tin, mixed in equal proportions, form a moderately hard, brittle, and very brilliant 
 alloy, capable of receiving an exquisite polish, and not easily tarnished by exposure to the air; it has 
 been occasionally manufactured into speculums for telescopes. Its sp. gr., according to Gellert, is less 
 than the mean of its constituent parts.” — Aikin’s Dictionary. 
 
 Bismuth is a brittle white metal, with a slight tint of red; its specific gravity is 9'822. ( Hatchett , 
 
 Phil. Trans. 1803.) It fuses at 476°, {Crichton,) 507°, ( Rudberg ,) and always crystallizes on cooling. 
 According to Chaudet, pure bismuth is somewhat flexible. A cast bar of the metal (see Rennie ) one- 
 tenth of an inch in diameter, supports, according to Muschenbroek, a weight of 48 pounds. Bismuth is 
 volatile at a high heat, and may be distilled in close vessels. It transmits heat more slowly than most 
 other metals, perhaps in consequence of its texture. ( Brande , 861.) 
 
 * The alloys are in general arranged under those metals which constitute respectively their largest proportional port** 
 
 but in some lew instances under those from which they derive their peculiar characters. 
 
METALS AND ALLOTS. 
 
 379 
 
 Bismuth is scarcely used alone, but it is employed for imparting fusibility to alloys, thus: 
 
 8 bismuth, 5 lead, 3 tin, constitute Newton’s fusible alloy, which melts at 212° F. 
 
 2 bismuth, 1 lead, 1 tin, Rose’s fusible alloy, which melts at 201° F. 
 
 5 bismuth, 3 lead, 2 tin, when combined melt at 199°. 
 
 8 bismuth, 5 lead, 4 tin, 1 type-metal, constitute the fusible alloy used on the Continent for producing 
 the beautiful casts of the French medals, by the clicliee process. The metals should be repeatedly 
 melted and poured into drops until they are well mixed. Mr. Charles Y. Walker substituted antimony 
 for the type-metal, and strongly recommends this latter in preference to the first-named fusible alloy 
 Electrotype Manipulation, Part II. p. 9-11, where the clichee process is described. 
 
 1 bismuth and 2 tin make the alloy Mr. Cowper found to be the most suitable for rose-engine and 
 eccentric-turned patterns, to be printed from after the manner of letter-press. He recommends the thin 
 plates to be cast upon a cold surface of metal or stone, upon which a piece of smooth paper is placed, 
 and then a metal ring; the alloy should neither burr nor crumble; if proper, it turns soft and silky; 
 when too crystalline, more tin should be added. 
 
 2 bismuth, 4 lead, 3 tin, 
 1 bismuth, 1 lead, 2 tin, 
 
 constitute pewterer's soft solders. 
 
 All these alloys must be cooled quickly to avoid the separation of the bismuth ; they are rendered 
 more fusible by a small addition of mercury. 
 
 Copper, with the exception of titanium, is the only metal which has a red color ; it has much lustre, 
 is very malleable and ductile, and exhales a peculiar smell when warmed or rubbed. It melts at a 
 bright-red or dull-white heat; or, according to Daniell, at a temperature intermediate between the 
 fusing points of silver and gold = 1996° Fabr. Its specific gravity varies from 8‘86 to 8'89 ; the 
 former being the least density of cast copper, the latter the greatest of rolled or hammered copper. 
 ( Brande , 812) 
 
 Copper is used alone for many important purposes, and very extensively for the following : namely, 
 sheathing and bolts for ships, brewing, distilling, and culinary vessels. Some of the fire-boxes for loco- 
 motive engines, boilers for marine engines, rollers for calico-printing and paper-making, plates for the 
 use of engravers, <fcc. 
 
 Copper is used in alloying gold and silver, for coin, plate, Ac., and it enters with zinc and nickel into 
 the composition of German silver. Copper alloyed with one-tenth of its weight of arsenicis so similar in 
 appearance to silver, as to have been substituted for it. 
 
 The alloys of copper, which are very numerous and important, are principally included under the 
 general name Brass. In the more common acceptation, brass means the yellow alloy of copper, with 
 about half its weight of zinc ; this is often called by engineers “ yellow brass.” 
 
 Copper alloyed with about one-ninth its weight of tin, is the metal of brass ordnance, which is very 
 generally called gun-metal; similar alloys used for the brasses or bearings of machinery, are called by 
 engineers hard brass, and also gun-metal ; and such alloys, when employed for statues and medals, are 
 called bronze. The further addition of tin leads to bell-metal, and speculum-metal, which are named 
 after their respective uses ; and when the proportion of copper is exceedingly small, the alloy constitutes 
 one kind of pewter. 
 
 Copper, when alloyed with nearly half its weight of lead, forms an inferior alloy, resembling gun 
 metal in color, but very much softer and cheaper, lead being only about one-fourth the value of tin, and 
 used in much larger proportion. This inferior alloy is called pot-metal, and also cock-metal, because it 
 is used for large vessels and measures, for the large tapis or cocks for brewers, dyers, and distillers, and 
 those of smaller kinds for household use. 
 
 Generally the copper is only alloyed with one of the metals, zinc, tin, or lead ; occasionally with two, 
 and sometimes with the three in various proportions. In many cases the new metals are carefully 
 weighed according to the qualities desired in the alloy, but random mixtures more frequently occur, 
 from the ordinary practice of filling the crucible in great part with various pieces of old metal, of un- 
 known proportions, and adding a certain quantity of new metal to bring it up to the color and hardness 
 required. This is not done solely from motives of economy, but also from an impression which appears 
 to be very generally entertained, that such mixtures are more homogeneous than those composed en- 
 tirely of new metals, fused together for the first time. 
 
 The remarks we have to oiler on these copper alloys will be arranged in the tabular form, in four 
 groups; and, to make them as practical as possible, they will be stated in the terms commonly used in 
 the brass-foundry. Thus, when the founder is asked the usual proportions of yellow brass, he will say, 
 6 to 8 oz. of zinc, (to every pound of copper being implied.) In speaking of gun-metal, he would not 
 say, it had one-ninth, or 11 per cent, of tin, but simply that it was 1-J, 2, or 21 oz., (of tin,) as the case 
 might be ; so that the quantity and kind of the alloy, or the addition to the pound of copper, is usually 
 alone named. 
 
 Alloys of copper and zinc only. — The marginal numbers denote the ounces of zinc added to every 
 
 pound of copper. 
 
 £ to I oz. Castings are seldom made of pure copper, as under ordinary circumstances it does not cast 
 soundly: about half an ounce of zinc is usually added, frequently in the shape of 4 oz. of brass 
 to every pound of copper ; and by others 4 oz. of brass are added to every two or three pounds 
 of copper. 
 
 1 to II oz. Gilding-metal, for common jewelry : it is made by mixing 4 parts of copper with 1 of cal- 
 amine brass ; or sometimes 1 lb. of copper with 6 oz. of brass. The sheet gilding-metal will be 
 found to match pretty well in color with the cast gun-metal, which latter does not ,.<tcnii of being 
 rolled ; they may be therefore used together when required. 
 
 8 oz. Red sheet-brass, made at Hegermiihl, or 5^ parts copper, 1 zinc. (Urc.) 
 
380 
 
 METALS AND ALLOYS. 
 
 B to 4 oz. Bath metal, pinchbeck, Mannheim gold, similor, and alloys bearing various names, and re- 
 sembling inferior jeweller’s gold greatly alloyed with copper, are of about this proportion: some 
 of them contain a little tin ; now, however, they are scarcely used. 
 
 6 oz. Brass, that bears soldering well. 
 
 6 oz. Bristol brass is said to be of this proportion. 
 
 8 oz. Ordinary brass, the general proportion ; less fit for soldering than G oz., it being more fusible. 
 
 8 oz. Emerson’s patent brass was of this proportion, and so is generally the ingot brass, made by sim 
 
 pie fusion of the two metals. 
 
 9 oz. This proportion is the one extreme of Muntz’s patent sheathing. See 10§. 
 
 lOf oz. Muntz’s metal, or 40 zinc and 60 copper. “ Any proportions,” says the patentee, “ between 
 the extremes 50 zinc and 50 copper, and 37 zinc 63 copper, will roll and work at the red-heat 
 but the first-r.amed proportion, or 40 zinc to 60 copper, is preferred. 
 
 The metal is cast into ingots, heated to a red-heat, and rolled and worked at that heat into 
 ships’ bolts and other fastenings and sheathing. 
 
 12 oz. Spelter-solder for copper and iron is sometimes made in this proportion; for brass work the 
 metals are generally mixed in equal parts. See 16 oz. 
 
 12 oz. Pale-yellow metal, fit for dipping in acids, is often made in this proportion. 
 
 16 oz. Soft spelter-solder, suitable for ordinary brass-work, is made of equal parts of copper and zinc. 
 About 14 lbs. of each are melted together and poured into an ingot-mould with cross-ribs, which 
 indents it into little squares of about 2 lbs. weight ; much of the zinc is lost. These lumps are 
 afterwards heated nearly to redness upon a charcoal fire, and are broken up, one at a time, with 
 great rapidity on an anvil, or in an iron pestle and mortar. The heat is a critical point ; if too 
 great, the solder is beaten into a cake or coarse lumps and becomes tarnished ; when the heat is 
 proper, it is nicely granulated, and remains of a bright-yellow color ; it is afterwards passed 
 through a sieve. Of course, the ultimate proportion is less than 16 oz. of zinc. 
 
 16 oz. Equal parts is the one extreme of Muntz’s patent sheathing. See 10f. 
 
 16£ oz. Hamilton and Parker’s patent mosaic gold, which is dark-colored when first cast, but on dip- 
 ping assumes a bp&_tiful golden tint. When cooled and broken, say the patentees, “ all yellow- 
 ness must cease, and the tinge vary from reddish-fawn or salmon color to a light purple or lilac, 
 and from that to whiteness.” The proportions are stated as from 52 to 58 zinc to 50 of copper, 
 or 16f to 17 oz. to the pound. 
 
 32 oz., or 2 zinc to 1 copper, a bluish-white brittle alloy, very brilliant, and so crystalline that it may 
 be pounded cold in a pestle and mortar. 
 
 128 oz., or 2 oz. of copper to every pound of zinc; a hard crystalline metal, differing but little from 
 zinc, but more tenacious ; it has been used for laps or polishing disks. 
 
 Remarks on the alloys of copper and zinc. — These metals seem to mix in all proportions. 
 
 The addition of zinc continually increases the fusibility, but from the extremely volatile nature of zinc, 
 these alloys cannot be arrived at with very strict regard to proportion. 
 
 The red color of copper slides into that of yellow brass at about 4 or 5 oz. to the pound, and remains 
 little altered unto about 8 or 10 oz. ; after this it becomes whiter, and when 32 oz. of zinc are added to 
 16 of copper, the mixture has the brilliant silvery color of speculum metal, but with a bluish tint. 
 
 These alloys, from about 8 to 16 oz. to the pound of copper, are extensively used for dipping, as in 
 an enormous variety of furniture work ; in all cases the metal is annealed before the application of the 
 scouring or cleaning processes, and of the acids, bronzes, and lackers subsequently used. 
 
 The alloys with zinc retain their malleability and ductility well, unto about 8 or 10 oz. to the pound ; 
 after this the crystalline character slowly begins to jjrevail. The alloy of 2 zinc and 1 copper, before 
 named, may be crumbled in a mortar when cold. 
 
 The ordinary range of good yellow brass, that files and turns well, is from about 4J to 9 oz. to the 
 pound. With additional zinc, it is harder and more crystalline ; with less, more tenacious, and it hangs 
 to the file like copper ; the range is wide, and small differences are not perceived. 
 
 Alloys of copper and tin only. — The marginal numbers denote the ounces of tin added to every 
 pound of copper. 
 
 Ancient Copper and Tin Alloys. 
 
 | oz. 
 
 If oz. 
 2 oz. 
 2f oz. 
 
 6 to 8 
 
 1 oz. 
 1| oz. 
 1 1 oz. 
 U to 
 
 2 oz. 
 24 oz. 
 
 3 oz. 
 3J oz. 
 
 4 oz. 
 
 Ancient bronze nails flexible, or 20 copper, 1 tin, 
 
 Soft bronze, or 9 to 1. 
 
 Medium bronze, or 8 to 1. 
 
 Hard bronze, or 7 to 1 . 
 
 oz. Ancient mirrors. 
 
 (Ure.) ' 
 
 f According to Pliny, as quoted by Wilkinson. 
 
 ) Ancient weapons and tools, by various analyses, or 8 to 15 per cent 
 ) tin ; medals from 8 to 12 per cent, tin, with 2 parts zinc added tc 
 (_ each 100, for improving the bronze color. (Ure.) 
 
 Modern Copper and Tin Alloys. 
 
 Soft gun-metal, that bears drifting, or stretching from a perforation. 
 
 A little harder alloy, fit for mathematical instruments ; or 12 copper and one very pure grain tm. 
 Still harder, fit for wheels to be cut with teeth. 
 
 2 oz. Brass ordnance, or 8 to 12 per cent, tin ; but the general proportion is one-ninth part of tin 
 Hard bearings for machinery. 
 
 Very hard bearings for machinery. By Muschenbroek’s tables it appears that the proportion 
 1 tin and 6 copper is the most tenacious alloy ; it is too brittle for general use, and contains 
 oz. to the pound of copper. 
 
 For some other alloys used in machinery, see alloys of copper, zinc, tin, and lead, p. 354 
 Soft musical bells. 
 
 Chinese gongs and cymbals, or 20 per cent. tin. 
 
 House bells. 
 
METALS AND ALLOYS. 
 
 381 
 
 <1 oz. Large bells. 
 
 5 oz. Largest bells. 
 
 7i to 8^ oz. Speculum metal. Sometimes one ounce of brass is added to every pound as the means 
 of introducing a trifling quantity of juic; at other times small proportions of silver are added; 
 the employment of arsenic was strongly advocated by the Rev. John Edwards. Lord Oxman- 
 town, now the Earl of Rosse, says, “ tin and copper, the materials employed by Newton in the 
 first reflecting telescope, are preferable to any other with which I am acquainted ; the best 
 proportions being 4 atoms of copper to 1 of tin, (Turner’s numbers;) in fact, 126-4 parts of cop- 
 per to 58’9 of tin.” — Trans. Royal Soc. 1840, p. 504. 
 
 The object agreed upon by all experimentalists appears to be the exact saturation of the copper with 
 the tin, and the proportionate quantities, differ very materially (in this and all other alloys) according 
 to the respective degrees of purity of the metals : for the most perfect alloys of this group, Swedish cop- 
 per and grain tin should be used. 
 
 Mr. Ross says : “ When the alloy is perfect, it should be white, glassy, and flaky. When the copper 
 is in excess, it imparts a red tint easily detected; when the tin is in excess, the fracture is granulated, 
 and also less white.” His practice is to pour the melted tin into the fluid copper when it is at the low- 
 est temperature that a mixture by stirring can be effected ; then to pour the mixture into an ingot, and 
 to complete the combination by remelting in the most gradual manner, by putting the metal into the 
 furnace as soon almost as the fire is lighted. Trial is made of a little piece taken from the pot imme- 
 diately prior to pouring. 
 
 82 oz. of tin to 1 lb. of copper make the alloy called by the pewterers “temper,” which is added ir 
 small quantities to tin for some kinds of pewter, called “ tin and temper,” in which the copper is fi\ 
 quently much less than 1 per cent. 
 
 Remarks on the alloys of copper and tin only. — These metals seem to mix in all proportions. 
 
 The addition of tin continually increases the fusibility, although when it is added cold it is apt tc 
 make the copper pasty, or even to set it in a solid lump in the crucible. 
 
 The red color of the copper is not greatly impaired in those proportions used by the engineer, namely 
 up to about 2-J oz. to the pound ; it becomes grayish white at 6, the limit suitable for bells, and quite 
 white at about 8, the speculum metal ; after this, the alloy becomes of a bluish cast. 
 
 The tin alloy is scarcely malleable at 2 oz., and soon becomes very hard, brittle, and sonorous ; ano 
 when it has ceased to serve for producing sound, it is employed for reflecting light. 
 
 The tough, tenacious character of copper under the tools rapidly gives way ; alloys of 1^ cut easily 
 2 J assume about the maximum hardness without being crystalline ; after this they yield to the file bj 
 crumbling in fragments rather than by ordinary abrasion in shreds, until the tin very greatly predomi 
 nates, as in the pewters : when the alloys become the more flexible, soft, malleable, and ductile, the less 
 copper they contain. 
 
 Alloys of copper and lead only. — The marginal numbers denote the ounces of lead added to every 
 pound of copper. 
 
 2 oz. A red-colored and ductile alloy. 
 
 4 oz. Less red and ductile ; neither of these is so much used as the following, as the object is to em- 
 ploy as much lead as possible. 
 
 6 oz. Ordinary pot-metal, called dry pot-metal, as this quantity of lead will be taken up without sep- 
 
 arating on cooling ; this is brittle when warmed. 
 
 7 oz. This alloy is rather short, or disposed to break. 
 
 8 oz. Inferior pot-metal, called wet pot-metal, as the lead partly oozes out in cooling, especially when 
 
 the new metals are mixed ; it is therefore always usual to fill the crucible in part with old 
 metal, and to add new for the remainder. This alloy is very brittle when slightly warmed. 
 More lead can scarcely be used, as it separates on cooling. 
 
 Remarks on the alloys of copper and lead only. — These metals mix in all proportions until the lead 
 amounts to nearly half ; after this they separate in cooling. 
 
 The addition of lead greatly increases the fusibility. 
 
 The red color of the copper is soon deadened by the lead ; at about 4 oz. to the pound the work 
 has a bluish leaden hue when first turned, but changes in an hour or so to that of a dull gun-metal 
 character. 
 
 When the lead does not exceed about 4 oz. the mixture is tolerably malleable, but with more lead ii 
 soon becomes very brittle and rotten ; the alloy is greatly inferior to gun-metal, and is principally used 
 on account of the cheapness of the mixture, and the facility with which it is turned and filed. 
 
 Alloys of copper, zinc, tin, and lead, d'c. — This group refers principally to gun-metal alloys, to which 
 more or less zinc is added by many engineers ; the quantity of tin in eveiy pound of the alloy, which is 
 expressed by the marginal numbers, principally determines the hardness. 
 
 Keller’s statues at Versailles are found as the mean of four analyses, to consist of 
 
 Copper 91 - 40, or about 14f ounces. 
 
 Zinc 5 53 “ 1 “ 
 
 Tin 1-70 “ f “ 
 
 Lead 1-37 “ $ “ 
 
 In 100 parts or the 16 ounces. 
 
 li to 2^ oz. tin to 1 lb. copper used for bronze medals, or 8 to 15 per cent, tin, with the addition of 2 
 parts in each 100 of zinc, to improve the color. 
 
 The modem so-called bronze medals of our mint are of pure copper, and are afterwards 
 bronzed superficially. 
 
 I \ oz. tin 4 zinc to 16 oz. copper. Pumps and works requiring great tenacity. 
 
382 
 
 METALS AND ALLOYS. 
 
 For wheels to be cut into teeth. 
 
 For turning-work. 
 
 For nuts of coarse threads, and bearings. 
 
 The engineer who uses these five alloys recommends melting the copper alone : the small 
 quantity of brass is then melted in another crucible, and the tin in a ladle ; the two latter are 
 added to the copper when it has been removed from the furnace ; the whole are stirred together 
 and poured into the moulds without being run into ingots. The real quantity of tin to every 
 pound of copper is about one-eighth ounce less than the numbers stated, owing to the addition of 
 the brass, which increases the proportion of copper. 
 
 \l oz. tin, 1| oz. zinc, to 1 lb. of copper. This alloy, which is a tough, yellow, brassy gun-metal, is used 
 for general purposes by a celebrated engineer ; it is made by mixing 1 £ lb” tin, 1 £ lb. zinc, and 
 10 lbs. of copper : the alloy is first run into ingots. 
 
 %£ oz. tin, £ oz. zinc, to 1 lb. of copper, used for bearings to sustain great weights. 
 
 2£ oz. tin, 2£ oz. zinc, to 1 lb. copper, were mixed by the late Sir F. Chantry, and a razor was made from 
 the alloy ; it proved nearly as hard as tempered steel, and exceedingly destructive to new files, 
 and none others would touch it. 
 
 1 oz. tin, 2 oz. zinc, 16 oz. brass. Best hard white metal for buttons. 
 
 £ oz. tin, 1£ oz. zinc, 16 oz. brass. Common ditto. (Phillips’s Dictionary.) 
 
 0 lbs. tin, 6 lbs. copper, 4 lbs. brass, constitute white solder. The copper and brass are first melted 
 together, the tin is added, and the whole stirred and poured through birch twigs into water to 
 granulate it ; it is afterwards dried and pulverized cold in an iron pestle and mortar. This 
 white solder was introduced as a substitute for silver solder in making gilt buttons. Another 
 button solder consists of 10 parts copper, 8 of brass, and 12 of spelter or zinc. 
 
 Remarks on alloys of copper, zinc, tin, lead, dec . — Ordinary yellow brass, (copper and zinc,) is 
 rendered very sensibly harder, so as not to require to be hammered, by a small addition of tin, say 4 
 or £ oz. to the lb. On the other hand, by the addition of £ to £ oz. of lead, it becomes more malleable 
 and casts more sharply. Brass becomes a little whiter for the tin, and redder for the lead. The addi- 
 tion of nickel to copper and zinc constitutes the so-called German silver. 
 
 Gun-metal (copper and tin) very commonly receives a small addition of zinc ; this makes the alloy 
 mix better, and to lean to the character of brass by increasing the malleability without materially re- 
 ducing the hardness. The standard measures for the Exchequer were made of a tough alloy of this 
 kind. The zinc, which is sometimes added in the form of brass, also improves the color of the alloy, 
 both in the recent and bronzed states. Lead, in small quantity, improves the ductility of gun-metal, 
 but at the expense of its hardness and color; it is seldom added. Nickel has been proposed as an ad- 
 dition to gun-metal by Mr. Donkin, and antimony by Dr. Ure. 
 
 Pot-metal (copper and lead) is improved by the addition of tin, and the three metals will mix in 
 almost any proportions : when the tin predominates, the alloy so much the more nearly approaches 
 the condition of gun-metaL Zinc may be added to pot-metal in very small quantity, but when the 
 zinc becomes a considerable amount, the copper takes up the zinc, forming a kind of brass, and leaves 
 the lead at liberty, and which, in great measure, separates in cooling. Zinc and lead are also very in- 
 disposed to mix alone, although a little arsenic assists their union by “ killing” the lead as in shot- 
 metal. Antimony also facilitates the combination of pot-metal; 7 lead, 1 antimony, and 16 copper 
 mixed perfectly well the first fusion, and the alloy was decidedly harder than 4 lead and 16 copper; 
 and apparently a better metal. “ Lead and antimony, though in small quantity, have a remarkable 
 effect in diminishing the elasticity and sonorousness of the copper alloys.” 
 
 Gold is of a deep and peculiar yellow color. It melts at a bright-red heat, equivalent, according 
 to Daniell, to 2016° of Fahrenheit’s scale, and when in fusion appears of a brilliant greenish color. Its 
 specific gravity is 19'3. It is so malleable that it may be extended into leaves which do not exceed 
 the one two hundred and eighty-two thousandth of an inch in thickness, or a single grain may be ex- 
 tended over 56 square inches of surface. This extensibility of the metal is well illustrated by gilt 
 buttons, 144 of which are gilt by 5 grains of gold, and less than even half that quantity is adequate by 
 giving them a very thin coating. It is also so ductile that a grain may be drawn out into 500 feet of 
 wire. The pure acids have no action upon gold. (Brande, 972.) 
 
 Gold, in the pure or fine state, is not employed in bulk for many purposes in the arts, as it is then 
 too soft to be durable. The gold foil used by dentists for stopping decayed teeth is perhaps as nearly 
 pure as the metal can be obtained : it contains about six grains of alloy in the pound troy, or the one- 
 thousandth part. Every superficial inch of this gold foil or leaf weighs J of a grain, and is 42 times as 
 thick as the leaf used for gilding. 
 
 The wire for gold lace prepared by the refiners for gold-lace manufacturers, requires equally fine 
 gold, as when alloyed it does not so well retain its brilliancy. The gold, in the proportion of about 100 
 grains to the pound troy of silver, or of 140 grains for double-gilt wire, is beaten into sheets as thin as 
 paper ; it is then burnished upon a stout red-hot silver bar, the surface of which has been scraped per- 
 fectly clean. When extended by drawing, the gold still bearing the same relation as to quantity, 
 namely, the 57th part of the weight, becomes of only one-third the thickness of ordinary gold-leaf used 
 for gilding. In water-gilding, fine gold is amalgamated with mercury, and washed over the gilding 
 metal, (copper and tin ;) the mercury attaches itself to the metal, and when evaporated by heat, it 
 leaves the gold behind in the dead or frosted state : it is brightened with the burnisher. (See Tech- 
 nological Repository, vol. ii., p. 361 : 1828.) By the electrotype process, a still thinner covering of 
 pure gold may be deposited on silver, steel, and other metals. Mr. Dent has introduced this method 
 »f protecting the steel pendulum-springs of marine chronometers and other time-pieces from rust. 
 
 Fine gold is also used for soldering chemical vessels made of platinum. 
 
 Gold alloys. — Gold-leaf, for gilding, contains from 3 to 12 grains of alloy to the oz., but generally i 
 
 l-J oz. tin 2 oz. brass 16 
 
 if “ 2 “ 16 
 
 2 “ 1£ “ 16 
 
 2 * “ 14 “ 16 
 
METALS AND ALLOYS. 
 
 3 S3 
 
 grains. The gold used by respectable dentists, for plates, is nearly pure, but necessarily contains about 
 6 grains of copper in the oz. troy, or one-eightieth part ; others use gold containing upwards of one- 
 third of alloy: the copper is then very injurious. 
 
 With copper, gold forms a ductile alloy of a deeper color, harder and more fusible than pure gold : 
 this alloy, in the proportion of 11 of gold to 1 of copper, constitutes standard gold ; its density is 17-157, 
 being a little below the mean, so that the metals slightly expand on combining. One troy pound of 
 this alloy is coined into 46|| sovereigns, or 20 troy pounds into 934 sovereigns and a half. The pound 
 was formerly coined into 44 guineas and a half. The standard gold of France consists of 9 parts of gold 
 and 1 of copper. ( Brande , 979.) 
 
 For Gold Plate the French have three different standards : 92 parts gold, 3 copper ; also 84 gold, 16 
 copper; and 75 gold, 25 copper. 
 
 In England, the purity of gold is expressed by the terms 22, 18, 16 carats, &c. The pound troy is 
 supposed to be divided into 24 parts, and the gold, if it could be obtained perfectly pure, might be 
 called 24 carats fine. 
 
 The “ Old Standard Gold,” or that of the present currency, is called fine, there being 22 parts of pure 
 gold to 2 of copper. 
 
 The “New Standard,” for watch-cases, <fec., is 18 carats of fine gold, and 6 of alloy. No gold of infe- 
 rior quality to 18 carats, or the “New Standard,” can receive the Hall mark; and gold of lower quality 
 is generally described by its commercial value, as 60 or 40 shilling gold, tire. 
 
 The alloy may be entirely silver, which will give a green color, or entirely copper for a red color ; 
 but the copper and silver are more usually mixed in the one alloy according to the taste and judgment 
 of the jeweller. 
 
 The following alloys of gold are transcribed from the memoranda of the proportions employed by a 
 practical jeweller of considerable experience.* 
 
 First group . — Different kinds of gold that are finished by polishing, burnishing, &c., without neces- 
 sarily requiring to be colored : 
 
 The gold of 22 carats fine, or the “ Old Standard,” is so little used, on account of its expense and 
 greater softness, that it has been purposely omitted. 
 
 18 carats, or New Standard gold, of yellow tint:* 
 15 dwt. 0 grs. gold. 
 
 2 dwt. 18 grs. silver. 
 
 2 dwt. 6 grs. copper. 
 
 20 dwt. 0 grs. 
 
 18 carats, or New Standard gold, of red tint:* 
 15 dwt. 0 grs. gold. 
 
 1 dwt. 18 grs. silver. 
 
 3 dwt. 6 grs. copper. 
 
 20 dwt. 0 grs. 
 
 16 carats, or Spring gold: this, when drawn or 
 rolled very hard, makes springs little inferior to 
 those of steel : 
 
 1 oz. 16 dwt. gold. or T12 
 6 dwt, silver. — -4 
 
 12 dwt. copper. — T2 
 
 80s. gold of yellow tint, or the fine gold of the jew- 
 ellers; 16 carats nearly : 
 
 1 oz. 0 dwt. gold. 
 
 7 dwt. silver. 
 
 5 dwt, copper. 
 
 1 oz. 12 dwt. 
 
 60s. gold of red tint, or 16 carats : 
 1 oz. 0 dwt. gold. 
 
 2 dwt. silver. 
 
 8 dwt. copper. 
 
 1 oz. 10 dwt. 
 
 40s. gold, or the old-fashioned jewellers’ gold, about 
 1 1 carats fine ; no longer used : 
 
 1 oz. 0 dwt. gold. 
 
 12 dwt. silver. 
 
 12 dwt. copper. 
 
 2 oz. 14 dwt. 
 
 2 -8 
 
 2 oz. 4 dwt. 
 
 Second group . — Colored golds ; these all require to be submitted to the process of wet-coloring, 
 which will be explained : they are used in much smaller quantities, and require to be very exactly pro- 
 portioned. 
 
 Full red gold : 
 
 5 dwt. gold. 
 
 5 dwt. copper. 
 
 Green gold : 
 
 5 dwt. 0 grs. gold. 
 21 grs. silver. 
 
 10 dwt. 
 
 5 dwt. 21 grs. 
 
 Red gold : 
 
 10 dwt. gold. 
 
 1 dwt. silver. 
 4 dwt. copper. 
 
 Gray gold : (Platinum is also called gray gold by 
 jewellers :) 
 
 3 dwt. 15 grs. gold. 
 
 1 dwt. 9 grs. silver. 
 
 15 dwt. 
 
 5 dwt. 0 grs. 
 
 * When it is not otherwise expressed, it will be understood all these alloys are made with fine gold, fine silver, and fine 
 sopper, obtained direct from the refiners. And to insure the standard gold passing the test of the Hall, 3 or 4 grains ad- 
 ditional of gold are usually added to every ounce. 
 
884 
 
 METALS AND ALLOYS. 
 
 Blue gold ; scarcely used : 
 5 dwt. gold. 
 
 5 dwt. steel filings. 
 
 10 dwt. 
 
 Antique gold, of a fine greenish yellow color ; 
 18 dwt. 9 grs. gold, or 18' 9 
 21 grs. silver, — 1' 3 
 18 grs. copper, — -12 
 
 20 dwt. 0 grs. 20' 0 
 
 Third group . — Gold solders: these are generally made from gold of the same quality and value aa 
 they are intended for, with a small addition of silver and copper, thus : 
 
 Solder for 22 carat gold : 
 
 1 dwt. 0 grs. of 22 carat gold. 
 2 grs. silver. 
 
 1 gr. copper. 
 
 1 dwt. 3 grs. 
 
 Solder for 60s. gold :# 
 1 dwt. 0 grs. of 60s. gold. 
 10 grs. silver. 
 
 8 grs. copper. 
 
 1 dwt. 18 grs. 
 
 Solder for 18 carat gold : 
 
 1 dwt. 0 grs. of IS carat gold. 
 2 grs. silver. 
 
 1 gr. copper. 
 
 1 dwt. 3 grs. 
 
 Solder for 40s. gold ; but middling silver solder is 
 more generally used : 
 
 1 dwt. fine gold. 
 
 1 dwt. silver. 
 
 2 dwt. copper. 
 
 4 dwt. 
 
 Dr. Hermstadt’s imitation of gold, which is stated not only to resemble gold in color, but also in spe- 
 cific gravity and ductility, consists of 16 parts of platinum, 7 parts of copper, and 1 of zinc, put in a 
 crucible, covered with charcoal powder, and melted into a mass. 
 
 Gold alloyed with platinum is also rather elastic, but the platinum whitens the alloy more rapidly 
 than silver. 
 
 Lead appears to have been known in the earliest ages of the world. Its color is bluish white ; it has 
 much brilliancy, is remarkably flexible and soft, and leaves a black streak on paper : when handled it 
 exhales a peculiar odor. It melts at about 612°, and by the united action of heat and air, is readily 
 converted into an oxide. Its specific gravity, when pure, is 11 '445 ; but the lead of commerce seldom 
 exceeds 11'35. ( Brande , 833.) 
 
 Lead is used in a state of comparative purity for roofs, cisterns, pipes, vessels for sulphuric acid, <Szc. 
 Ships were sheathed with lead and with wood from before the Christian era to 1450, after which wood 
 was more commonly employed, and in 1790 to 1800 copper sheathing became general; of late years, 
 lead with a little antimony has likewise been used, also Muntz’s sheathing, an alloy of copper ana zinc 
 and galvanized sheet-iron. The most important alloys are those employed for printers’ type, namely, 
 about 
 
 3 lead, 1 antimony, for the smallest, hardest, and most brittle types. 
 
 4 lead, 1 antimony, for small, hard, brittle types. 
 
 5 lead, 1 antimony, for types of medium size. 
 
 6 lead, 1 antimony, for large types. 
 
 7 lead, 1 antimony, for the largest and softest types. 
 
 The small types generally contain from 4 to 6 per cent, of tin, and sometimes also 1 to 2 per cent, 
 of copper ; but as old metal is always used with the new, the proportions are not exactly known. 
 
 Stereotype plates contain about 4 to 8 parts of lead to one of antimony. 
 
 Baron Wetterstedt’s patent sheathing for ships consists of lead with from 2 to 8 per cent, of anti- 
 mony ; about 3 per cent, is the usual quantity. The alloy is rolled into sheets. 
 
 Similar alloys, and those of lead and tin in various preparations, are much used for emery-wheels and 
 grinding-tools of various forms by the lapidary, engineer, and others. The latter also employs these 
 readily fused alloys for temporary bearings, guides, screw-nuts, &c. 
 
 Organ-pipes consist of lead alloyed with about half its quantity of tin to harden it. The mottled or 
 crystalline appearance so much admired shows an abundance of tin. 
 
 Shot-metal is said to consist of 40 lbs. of arsenic to one ton of lead. 
 
 In casting sheet-lead, the metal was poured from a swing-trough upon a long and nearly horizontal 
 table, covered with a thin layer of coarse damp sand, previously levelled with a metal rule or strike. 
 The thickness of the fluid metal was determined by running the strike along the table before the lead 
 cooled, the excess being thus swept into a spill-trough at the lower end of the table ; but the sheet-lead 
 now more commonly used is cast in a thick slab, and reduced between laminating rollers ; it is known 
 as “ milled lead.” 
 
 The metal for organ-pipes is prepared by allowing the metal to escape through a slit in the trough, 
 as it is slid along a horizontal table, so as to leave a trail of metal behind it ; the thickness of the metal 
 is regulated by the width of the slit through which it runs, and the rapidity of the traverse ; a piece of 
 cloth or ticken is stretched upon the casting-table. The metal is planed to thickness, bent up, and 
 soldered into the pipes. 
 
 Lead pipes are cast as hollow cylinders and drawn out upon triblets ; they are also cast of indefinite 
 
 * By others, 4 grains of brass are added to the solder ; it then fuses beautifully and is of good color. Zinc is sometimes 
 added to other gold solders to increase their fusibility ; the zinc (or brass, when used) should be added at the last mo- 
 ment, to lessen the volatilization of the zinc. 
 
METALS AND ALLOYS. 
 
 385 
 
 length without drawing. A patent was taken out for casting a sheath of tin within the lead, but it has 
 been abandoned. 
 
 Lead shot are cast by letting the metal run through a narrow slit, into a species of colander at the 
 top of a lofty tower ; the metal escapes in drops, which, for the most part, assume the spherical form 
 before they reach the tank of water into which they' fall at the foot of the tower, and this prevents their 
 being bruised. The more lofty the tower, the larger the shot that can be produced ; the good and bad 
 shot are separated by throwing small quantities at a time upon a smooth board nearly horizontal, which 
 is slightly wriggled ; the true or round shot run to the bottom, the imperfect ones stop by the way, and 
 are thrown aside to be remelted ; the shot are afterwards riddled or sifted for size, and churned in a 
 barrel with black-lead. 
 
 Mr. Joseph Manton took out a patent for amalgamating the stirface of leaden shot with mercury. 
 One pound of mercury was added to every cwt. of shot; they were churned together in a revolving 
 barrel nearly full of water, until the shot assumed a silvery coat. These shot were stated to foul the 
 barrel of the gun in a less degree than others, and also to be less injurious to the game after it had 
 been killed. 
 
 Mercury is a brilliant white metal, having much of the color of silver, whence the terms hydrargyrum 
 argentum vivutn , and quicksilver. It lias been known from very remote ages. It is liquid at all com- 
 mon temperatures ; solid and malleable at — 40° F., and contracts considerably at the moment of 
 congelation. It boils and becomes vapor at about 670°. Its specific gravity at 60° is 13'5. In the solid 
 state its density exceeds 14. The specific gravity of mercurial vapor is 6'976. (Dumas, Ann. de Ch. et 
 Ph. xxxiii., Brande , 928.) 
 
 Mercury is used in the fluid state for a variety of philosophical instruments, and for pressure gages 
 for steam-engines, &c. It is sometimes, though rarely, employed for rendering alloys more fusible ; it is 
 used with tin-foil for silvering looking-glasses, and it has been employed as a substitute for water in hard- 
 ening steel. Mercury forms amalgams with bismuth, copper, gold, lead, palladium, silver, tin, and zinc. 
 
 Mercury is commonly used for the extraction of gold and silver from their ores by amalgamation, and 
 also in water-gilding. See Gold. 
 
 Nickel is a white, brilliant metal, which acts upon the magnetic needle, and is itself capable of be- 
 coming a magnet. Its magnetism is more feeble than that of iron, and vanishes at a heat somewhat 
 below redness, 630°, (Faraday.) It is ductile and malleable. Its specific gravity varies from 8'27 to 
 8 p 40 when fused, and after hammering from 8'69 to 9. It is not oxidized by exposure to air at common 
 temperatures, but when heated in the air it acquires various tints, like steel ; at a red heat it becomes 
 coated by a gray oxide. ( Brande , 802.) 
 
 Nickel is scarcely used in the simple state ; Mr. Brande mentions, however, that he has seen a Bava- 
 rian coin that had been struck in it ; but it is principally used together with copper and zinc, in alloys 
 that are rendered the harder and whiter the more nickel they contain ; they are known under the 
 names of albata, British plate, electrum^ German silver, pakfong, teutanag, &c. : the proportions differ 
 much, according to price ; thus the 
 
 Commonest are 3 to 4 parts nickel, 20 copper, and 16 zinc. 
 
 Best are .6 to 6 parts nickel, 20 copper, and 8 to 10 zinc. 
 
 About two-thirds of this metal is used for articles resembling plated goods, and some of which are 
 also plated, (see silver ;) the remainder is employed for harness, furniture, drawing and mathematical 
 instruments, spectacles, the tongues for accordions, and numerous other small works. 
 
 The white copper of the Chinese, which is the same as the German silver of the present day, is com- 
 posed, according to the analysis of Dr. Fyfe, of 
 
 31'6 parts of nickel, 40'4 of copper, 25 4 of zinc, and 2'6 of iron. 
 
 17'48 “ “ 53 39 “ 13-0 “ Frick’s Imitative Silver. 
 
 The white copper manufactured at Sutil, in the duchy of Saxe Hildburghausen, is said b} r Keferstein 
 to consist of copper 88'000, nickel 8.753, sulphur, with a little antimony, 0'750,silex, clay, and iron, 1-75. 
 The iron is considered to be accidentally introduced into these several alloys, along with the nickel, and 
 a minute quantity is not prejudicial. 
 
 Iron and steel have been alloyed with nickel ; the former, (the same as the meteoric iron which 
 always contains nickel,) is little disposed to rust, whereas the alloy of steel with nickel is worse in 
 that respect than steel not alloyed. 
 
 Palladium is of a dull-white color, malleable and ductile. Its specific gravity is about 1 1-3, or 11'86 
 when laminated. It fuses at a temperature above that required for the fusion of gold. ( Brande , 998.) 
 
 “ Palladium is a soft metal, but its alloys are all harder than the pure metal. With silver it forms 
 a very tough malleable alloy, fit for the graduations of mathematical instruments, and for dental 
 surgery, for which it is much used by the French ; with silver and copper, palladium makes a very 
 springy alloy, used for the points of pencil-cases, inoculating lancets, tooth-picks, or any purpose where 
 elasticity and the property of not tarnishing are required ; thus alloyed it takes a high polish. Pure 
 palladium is not fusible at ordinary temperatures, but at a high temperature it agglutinates so as to be 
 afterwards malleable and ductile.” — ■ W. Cock. 
 
 This useful metal was discovered by Dr. Wollaston, in 1803, and it has recently been found in some 
 abundance in the gold ores of the Minas Geraes district ; the process now employed for its separation 
 was discovered by Mr. P. N. Johnson. Palladium is calculated thoroughly to fulfil many of the pur- 
 poses to which platinum and gold are applied in the useful arts, and from its low specific gravity, it 
 may be obtained at about half the price of an equal hulk of platinum, and at one-eiglith that of gold ; 
 and it equally resists the action of mineral acids and sulphuretted hydrogen. — London Journal of Sci- 
 ence for 1840. 
 
 Palladium was used in the construction of the balances for the United States’ Mint. 
 
 Platinum is a white metal, extremely difficult of fusion, and unaltered bv the joint action of heat 
 Vol. II.— 25 
 
386 
 
 METALS AND ALLOYS. 
 
 and air. It varies in density from 21 to 21-5, according to the degree of mechanical compression whici 
 it has sustained ; it is extremely ductile, but cannot be beaten into such thin leaves as gold and silver 
 ( Brande , 4th Ed. p. 822.) 
 
 The particles of the generality of metals, when separated from the foreign matters with which 
 they are combined, are joined into solid masses by simple fusion ; but platinum being nearly infu- 
 sible when pure, requires a very different treatment, which was introduced by Dr. Wollaston, and 
 is now conducted in the following manner by Messrs. Johnson and Cock, of London, the celebrated 
 metallurgists. 
 
 The platinum is first dissolved chemically, and it is then thrown down in the state of a precipitate ; 
 next it is partly agglutinated in the crucible into a spongy mass, and is then compressed whilst cold in 
 a rectangular mould by means of a powerful fly-press or other means, which, in operating upon 500 
 ounces, converts the platinum into a dense block about 5 inches by 4, and 2 J inches thick. This block 
 is heated in a smith’s forge, with two tuyeres meeting at an angle, at which spot the platinum is placed 
 amidst the charcoal fire ; when it has reached the welding point, or almost a blue heat, it receives one 
 blow under a heavy drop, or a vertical hammer, somewhat like a pile-driving engine ; it then requires 
 to be reheated, and it thus receives a fresh blow about every 20 minutes, and in a week or ten days it 
 is sufficiently welded or consolidated on all sides to admit of being forged into bars, and converted into 
 sheets, rods, or wires by the ordinary means. 
 
 The motive for operating upon so great a quantity is for making the large pans for concentrating 
 sulphuric acid, in only two or three pieces, which are soldered together with line gold. In France, 
 2,000 ounces are sometimes welded into one mass, so that the vessels may be absolutely entire, a prac- 
 tice which is considered in this country to be unnecessarily costly. For small quantities the treatment 
 is the same, but in place of the drop, the ordinary flatter and sledge-hammer are used. 
 
 Platinum is exceedingly tough and tenacious, and “ hangs to the file worse than copper,” on which ac- 
 count, when it is used for the graduated limbs of mathematical instruments, the divisions should be cut 
 with a diamond point, and which is the best instrument for fine graduations of all kinds, and for ruling 
 grounds, or the lined surfaces for etching. 
 
 Platinum is employed in Russia for coin. This valuable metal is used in various chemical and philo- 
 sophical apparatus, in which resistance to fusion or to the acids is essential. 
 
 The alloys of platinum are scarcely used in the arts ; that with a small quantity of copper is em- 
 ployed in Paris for dental surgery. For alloys of platinum and steel, see Quarterly Journal of the 
 Royal Inst.., vol ix., p. 328. The alloy of equal parts of steel aud platinum is therein highly spoken of 
 as a mirror. 
 
 “Dr. Yon Eckart’s alloy contains platinum 2’40, silver 3'53, and copper 1 17 1 . It is highly elastic, 
 of the same specific gravity as silver, and not subject to tarnish ; it can be drawn to the finest wire 
 from Jth of an inch diameter, without annealing, and does not lose its elasticity by annealing. It is 
 liighly sonorous, and bears hammering red-hot, rolling and polishing.” 
 
 Mr. Ross added to silver one-fourth of its weight of platinum, and he considers that it took up one- 
 tenth its weight. The alloy became much harder than silver, capable of resisting the tarnishing influ- 
 ences of sulphur and hydrogen, and was fit for graduations. 
 
 An alloy of platinum with ten parts of arsenic is fusible at a heat a little above redness, and may 
 therefore be cast in moulds. On exposing the alloy to a gradually increasing temperature in open ves- 
 sels, the arsenic is oxidized and expelled, and the platinum recovers its purity and infusibility. — Turner's 
 Chemistry. 
 
 Tin also so greatly increases the fusibility of platinum, that it is hazardous to solder the latter metal 
 with tin solder, although gold is so used. 
 
 Platinum, as well as gold, silver, and copper, are deposited by the electrotype process ; and silver 
 plates thus platinized are employed in Smee’s Galvanic Battery. 
 
 Rhodium is a white metal, very difficult of fusion; its specific gravity is about 11 : it is extremely 
 hard. When pure, the acids do not dissolve it. ( Brande , 1001.) 
 
 Rhodium was discovered in 1803, by Dr. Wollaston, and has been long employed for the nibs of 
 pens, which have been also made of ruby, mounted on shafts of spring gold ; these kinds have had to 
 endure for the last 7 or 8 years the rivalry of “ Hawkins’ everlasting Pen,” of which latter, the author 
 from many months’ constant use can speak most favorably. “ The everlasting pen,” says the inventor, 
 “is made of gold, tipped with a natural alloy, which is as much harder than rhodium as steel is harder 
 than lead ; will endure longer than the ruby, yields ink as freely as the quill, is as easily wiped, and if 
 left unwiped is not corroded.” See also Mec. Mag., 1840, p. 554. Mr. Hawkins employs the natural 
 alloy of iridium and osmium, two scarce metals, discovered by Tennant amongst the grains of platinum ; 
 the alloy is not malleable, and is so hard as to require to be worked with diamond powder. The metals 
 rhodium, iridium, and osmium, are not otherwise employed in the arts than for pens, although steel 
 has been alloyed with rhodium. See also the Quarterly Journal, Royal Inst., vol. ix. 
 
 Silver is of a more pure white than any other metal ; it has considerable brilliancy, and takes a high 
 polish. Its specific gravity varies between 10’4, which is the density of cast silver, and 10’5 to 10'6, 
 which is the density of rolled or stamped silver. It is so malleable and ductile, that it may be ex- 
 tended into leaves not exceeding a ten-thousandth of an inch in thickness, and drawn into wire much 
 finer than a human hair. Silver melts at a bright-red heat, estimated by Mr. Daniell at 1873° of Fah- 
 renheit’s scale, and when in fusion appears extremely brilliant. ( Brande , 953.) 
 
 Silver is but little used in the pure unalloyed state, on account of its extreme softness, but it is gen- 
 erally alloyed with copper in about the same proportion as in our coin, and none of inferior value can 
 receive the “Hall mark.” Diamonds are set in fine silver, and in silver containing 3 to 12 grs. of cop- 
 per in the ounce ; the work is soldered with pure tin. 
 
 The sheet, -metal for plated works is prepared by fitting together very truly, a short stout bar of cop- 
 per aud a thinner plate of silver; when scraped perfectly clean, they are tied strongly together with 
 
METALS AND ALLOYS. 
 
 387 
 
 binding wire, and united by partial fusion without the aid of solder. The plated metal is then rolled 
 out, and the silver always remains perfectly united, and of the same proportional thickness as at first 
 Additional silver may be burnished on hot, when the surfaces are scraped clean, as explained under 
 gold ; this is done either to repair a defect, or to make any part thicker for engraving upon, and the 
 uniformity of surface is restored with the hammer. In addition to its use for articles of luxury, the 
 important service of copper plated with silver for the parabolic reflectors of lighthouses must not be 
 overlooked ; these are worked to the curve with great perfection by the hammer alone. 
 
 Plated spoons, forks, harness, and many other articles, are made of iron, copper, brass, and German 
 silver, either cast or stamped into shape ; the objects are then filed and scraped perfectly clean ; and 
 fine silver, often little thicker than paper, is attached with the aid of tin solder and heat ; the silver is 
 rubbed close upon every part with a burnisher. 
 
 The electrotype process is also used, under Elkington & Co.’s patent, for plating several of the metals 
 with silver, which it does in the most uniform and perfect manner ; the silver added is charged by 
 weight at about three times the price of the metal ; the German silver, or albata, is generally used for 
 the interior substance, as when the silver is partially worn through, the white alloy is not so readily 
 detected as iron or copper. 
 
 Silver alloys. — Mr. Brande says, “ The alley with copper constitutes plate and coin ; by the addition 
 of a small proportion of copper to silver, the metal is rendered harder and more sonorous, while its 
 color is scarcely impaired. Even with equal weights of the two metals, the compound is white ; the 
 maximum of hardness is obtained when the copper amounts to one-fifth of the silver. The standard 
 silver of this country consists of 1 IjA pure silver, and copper, or 11T0 silver, and 0'90 copper. A 
 pound of troy, therefore, is composed of 11 oz. 2 dwts. pure silver, and 18 dwts. of copper. Its density 
 is 10'3 ; its calculated density is 105, so that the metals dilate a little on combining. The French silver 
 coin is constituted of 9 silver and 1 copper.” {Brande.) The French billon coin is 1 silver and 4 
 copper. {Kelly.) 
 
 “For silver plate, the French proportions are 9^- parts silver, ^ copper, and for trinkets, 8 parts silver, 
 2 copper.” 
 
 Silver solders are made in the following proportions : 
 
 Hardest silver solder, 4 parts fine silver, and 1 part copper ; this is difficult to fuse, but is occasion- 
 ally employed for figures. 
 
 Hard silver solder, 3 parts sterling silver, and 1 part brass wire, which is added when the silver is 
 melted, to avoid wasting the zinc. 
 
 Soft silver solder for general use, 2 parts fine silver, and 1 part brass wire. By some few, f part of 
 arsenic is added, to render the solder more fusible and white, but it becomes less malleable ; the arsenic 
 must be introduced at the last moment, with care to avoid its fumes. 
 
 Silver is also soldered with tin solder, (2 tin, 1 lead,) and with pure tin. 
 
 Silver and mercury are used in the plastic metallic stopping for teeth. 
 
 Tin has a silvery-wliite color, with a slight tint of yellow ; it is malleable, though sparingly ductile. 
 Common tin-foil, which is obtained by beating out the metal, is not more than 1 -1000th of an inch in 
 thickness, and what is termed white Butch metal is in much thinner leaves. Its specific gravity fluctu- 
 ates from 7-28 to 7 '6, the lightest being the purest metal. When bent it occasions a peculiar crackling 
 noise, arising from the destruction of cohesion amongst its particles. 
 
 When a bar of tin is rapidly bent backwards and forwards several times successively, it becomes so 
 hot that it cannot be held in the hand. When rubbed it exhales a peculiar odor. It melts at 442°, 
 and by exposure to heat and air is gradually converted into a protoxide. {Brande.) 
 
 Pure tin is commonly used for dyers’ kettles ; it is also sometimes employed for the bearings of loco- 
 motive carriages and other machinery. This metal is beaten into very large sheets, some of which 
 measure 200 by 100 inches, and are of about the thickness of an ordinary card ; the small-sized foil is 
 stated not to exceed one-thousandth of an inch in thickness. The metal is first laminated between 
 rollers, and then spread one sheet at a time upon a large iron surface or anvil, by the direct blows or 
 hammers with very long handles ; great skill is required to avoid beating the sheets into holes. The 
 large sheets of tin-foil are only used for silvering looking-glasses by amalgamation with mercury. See 
 Mr. Farrow’s apparatus, Trans. Soc. of Arts, vol. 49, p. 146. Tin-foil is also used for electrical pur- 
 poses. The amalgam used for electrical machines, is 7 tin, 3 zinc, and 2 mercury. 
 
 Tin is drawn into wire, which is soft and capable of being bent and unbent many times without 
 breaking ; it is moderately tenacious, and completely inelastic. Tin tube is extensively used for gas 
 fittings, and many other purposes ; it has been recently introduced in an ingenious manner for the 
 formation of very cheap vessels, for containing artists’ and common colors, besides numerous other 
 solid substances and fluids, required to be hermetically sealed, with the power of abstracting small 
 quantities. 
 
 Tin plate is an abbreviation of tinned iron plate ; the plates of charcoal iron are scoured bright, 
 pickled, and immersed in a batli of melted tin covered with oil, or with a mixture of oil and common 
 resin ; they come out thoroughly coated. Tinned iron wire is similarly prepared ; there are several 
 niceties in the manipulations of each of these processes which cannot be noticed in this place. 
 
 Tin is one of the most cleanly and sanatory of metals, and is largely consumed as a coating for culi- 
 nary vessels, although the quantity taken up in the tinning is exceedingly small, and which was noticed 
 by Pliny. 
 
 Tin imparts hardness, whiteness, and fusibility to many alloys, and is the basis of different solders, 
 pewters, Britannia metal, and other important alloys, all of which have a low power of conducting heat. 
 
 Pewter is principally tin ; mostly lead is the only addition, at other times copper, but antimony, zinc, 
 <tc., are used with the above, as will be separately adverted to. The exact proportions are unknown 
 even to those engaged in the manufacture of pewter, as it is found to be the better mixed when it con 
 tains a considerable portion of old metal, to which new metal is added by trial. 
 
388 
 
 METALS AND ALLOYS. 
 
 In order to regulate the quality of pewter wares, the Tenderers’ Company published in 1772 “A 
 Table of the Assays of Metal, and of the Weights and Dimensions of the several sorts of Pewter 
 Wares,” and they threatened with expulsion from their guild, any who departed from the regulations 
 given in this now scarce and disregarded pamphlet. 
 
 The assay is made by casting a small button of the metal to be tried in a brass mould, which is sc 
 proportioned that the button, if pure tin, weighs exactly 182 grains ; all the metals added to the tin 
 being heavier than the latter : the buttons or assays are the heavier the less tin they contain, and at 
 page 14 of the pamphlet the following scale is given : 
 
 Assay of pure tin 182 grains. 
 
 Ditto of fine or plate metal 1£ grains heavier than tin, or 183^ “ 
 
 Ditto of trifling metal “ “ 1854 “ 
 
 Ditto of ley metal 164 “ “ 198| “ 
 
 sad it may be added, although an unauthorized addition, that equal parts of tin and lead are about 
 fifty grains heavier than tin, or 232 grains. 
 
 Some pewters are now made nearly as common as the last proportion : when cast they are black, 
 shining and soft ; when turned, dull and bluish. Other pewters only contain l-5th or l-6th of lead ; these 
 when cast are white, without gloss, and hard ; such are pronounced very good metal, and are but little 
 darker than tin. The French legislature sanctions the employment of 18 per cent, of lead with 82 of 
 tin, as quite harmless in vessels for wine and vinegar. 
 
 The finest pewter, frequently called “tin and temper,” consists mostly of tin, with a very little cop- 
 per, which makes it hard and somewhat sonorous, but the pewter becomes brown-colored when the 
 copper is in excess. The copper is melted, and twice its weight of tin is added to it, and from about 
 d to 7 lbs. of this alloy, or the “ temper,” are added to every block of tin weighing from 360 to 390 
 pounds. 
 
 Antimony is said to harden tin and to preserve a more silvery color, but is little used in pewter. 
 Zinc is employed to cleanse the metal rather than as an ingredient ; some stir the fluid pewter with a 
 thin strip, half zinc and half tin ; others allow a small lump of zinc to float on the surface of the fluid 
 metal whilst they are casting, to lessen the oxidation. 
 
 Britannia metal, or white metal, is said to consist of 3^- cwt. of block tin, 28 lbs. antimony, 8 lbs. cop- 
 per, and 8 lbs. brass ; it is cast into ingots and rolled into very thin sheets. This manufacture was in 
 troduced in about the year 1770, by Jessop and Hancock. 
 
 Tin solders are very much used in the arts, and according to Dr. Turner, 
 
 1 tin 3 lead, the coarse plumber’s solder, melts at about 500 F. 
 
 2 “ 1 “ the ordinary or fine tin solder “ “ “ 360 F. 
 
 Zinc. — A bluish-white metal, with considerable lustre, rather hard, of a specific gravity of about 6 8 
 in its usual state, but, when drawn into wire, or rolled into plates, its density is augmented to 7 or 7'2. 
 In its ordinary state at common temperatures, it is tough, and with difficulty broken by blows of the 
 hammer. It becomes very brittle when its temperature approaches that of fusion, which is about 773° ; 
 but at a temperature a little above 212°, and between that and 300°, it becomes ductile and malleable, 
 and may be rolled into thin leaves, and drawn into moderately fine wire, which, however, possesses but 
 little tenacity. When a mass of zinc, which has been fused, is slowly cooled, its fracture exhibits a 
 lamellar and prismatic crystalline texture. — Brando, 770. 
 
 Zinc, which is commercially known as spelter, although it is always brittle when cast, has of late 
 years taken its place amongst the malleable metals ; the early stages of its manufacture into sheet, foil, 
 and wire, are stated to be conducted at a temperature somewhat above that of boilrng water ; and it 
 may be afterwards bent and hammered cold, but it returns to its original crystalline texture when re-' 
 melted. It has been applied to many of the purposes of iron, tinned-iron, and copper ; it is less subject 
 to oxidation from the effects of the atmosphere than the iron, and much cheaper, although less tenacious, 
 ductile, or durable than the copper. The sheet metals when bent lengthways of the sheet, (or like a 
 roll of cloth,) are less disposed to crack than if bent sideways. In this respect zinc and sheet-iron are the 
 worst : the risk is lessened when they are warmed. 
 
 Zinc is applied as a coating to preserve iron from rust. 
 
 Zinc mixed with one-twentieth its weight of speculum metal, may be melted in an iron ladle, and 
 made to serve for some of the purposes of brass, such as common chucks. The alloy is sufficient to 
 modify the crystalline character, but reserves the toughness of the zinc; it will not, however, bear ham- 
 mering, either hot or cold. Four atoms of zinc and one of tin, or 133 f 2 and 57'9, make a hard, malleable, 
 aud less crystalline alloy. 
 
 Biddery ware, manufactured at Bidderv, a large city, 60 miles N. W. of Hyderabad in the East In- 
 dies. and also at Benares, is said by Dr. Heyne to consist of copper, 16 oz. ; lead, 4 oz. ; and tin, 2 oz., 
 melted together : and to every 3 oz. of this alloy, 16 oz. of spelter or zinc are added. The metal is used 
 as an inferior substitute for silver, and resembles some sorts of pewter. 
 
 The foregoing alloys are mostly derived from actual practice, and although it has been abundantly 
 shown that alloys are most perfect, when mixed according to atomic proportions, or by multiples 
 of their chemical equivalents, yet this excellent method is little adopted, owing to various interfer- 
 ences. 
 
 For example, it is in most cases necessary, from an economic view, to mix some of the old alloys, (the 
 proportions of which are uncertain,) along with the new metals. In most cases also unless the fusion 
 and refusion of the alloys are conducted with considerably more care than ordinary practice ever attains, 
 or really demands, the loss by oxidation completely invalidates any nice attempts at proportion ; and 
 
METALS AND ALLOYS. 
 
 38P 
 
 wliicli proportions can be alone exactly- arrived at, when the combined metals are nearly or quite 
 pure. 
 
 Hardness, fracture, and color of alloys. — The- object of this division of our article is to explain, in a 
 general way, some of the peculiarities and differences amongst alloys, in the manner of a supple- 
 ment to the list ; prior to entering on the means of melting tire metals, without which process 
 alloys cannot be made : yet notwithstanding that the list contains the greater number of the alloys in 
 ordinary use, and many others, it is merely a small fraction of those which might be made, for, says l)r. 
 Turner, “It is probable that each metal is capable of uniting in one or more proportions with every other 
 metal, and on this supposition the number of alloys would be exceedingly numerous.”* * * § 
 
 It is also stated by the same distinguished authority, that “Metals appear to unite with one another 
 in every proportion, precisely in the same manner as sulphuric acid and water. Thus there is no limit 
 to tire number of alloys of gold and copper.” The same might be said of many other metals, and when 
 the alloys compounded of three, four, or more metals, are taken into account., the conceivable number oi 
 alloys becomes almost unlimited. “It is certain, however, that metals, have a tendency to combine in 
 definite proportion ; for several atomic compounds of this kind occur native.” “ It is indeed possible 
 that the variety of proportions in alloys is rather apparent than real, arising from the mixture of a few 
 definite compounds with each other, or with uncombined metal ; an opinion not only suggested by the 
 mode in which alloys are prepared, but in some measure supported by observation.” •)■ 
 
 It appears to be scarcely possible to give any sufficiently general rules by which the properties of 
 alloys may be safely inferred from those of their constituents ; for although, in many cases, the working 
 qualities and appearance of an alloy, may be nearly a mean proportional between the nature and quan- 
 tities of the metals composing it ; yet in other and frequent instances the deviations are excessive, as 
 will be seen by several of the examples referred to. 
 
 Thus, when lead, a soft and malleable metal, is combined with antimony, which is hard, brittle, and 
 crystalline, in the proportions of from twelve to fifty parts of lead to one of antimony, a flexible alloy 
 is obtained, resembling lead, but somewhat harder, and which is rolled into sheets for sheathing ships. 
 Six parts of lead and one of antimony are used for the large soft printers’ types, which will bend 
 slightly, but are considerably harder than the foregoing; and three parts of lead and one of antimony 
 are employed for the smallest types, that are very hard and brittle, and will not bend at all : antimony 
 being the more expensive metal, is used in the smallest quantity that will suffice.]; The difference in 
 specific gravity between lead and antimony constantly interferes, and unless the type metal is fre- 
 quently stirred, the lead, from being the heavier metal, sinks to the bottom, and the antimony is dispro- 
 portionally used from the surface-! 
 
 In the above examples, the- differences arising from the proportions appear intelligible enough, as 
 when the soft lead prevails, the mixture is much like the lead ; and as the hard, brittle antimony is 
 increased, the alloy becomes hardened, and more brittle : with the proportion of four to one, the frac- 
 ture is neither reluctant like that of lead, nor foliated like antimony, but assumes very nearly the grain 
 and color of some kinds of steel and cast-iron. In like manner when tin and lead are alloyed, the for- 
 mer metal imparts to the mixture some of its hardness, whiteness, and fusibility, in proportion to its 
 quantity; as seen in the various qualities of pewter, in which however copper, and sometimes zinc or 
 antimony, are found. 
 
 The same agreement is not always met with ; as nine parts of copper, w T hich is red, and one part of 
 tin, which is white, each very malleable and ductile metals, make the tough, rigid metal used in brass 
 ordnance, from which it obtains its modern name of gun-metal, but which neither admits of rolling nor 
 drawing into wire ; the same alloy is described by Pliny as the soft bronze of his day. The continual 
 addition of the tin, the softer metal, produces a gradual increase of hardness in the mixture ; with about 
 one-sixth of tin the alloy assumes its maximum hardness consistent with its application to mechanical 
 uses ; with one-fourth to one-third tin it becomes highly elastic and sonorous, and its brittleness rather 
 than its hardness is greatly increased. 
 
 When the copper becomes two, and the tin one part, the alloy is so hard as not to admit of being cut 
 with steel tools, but crumbles under their action ; when struck with a hammer, or even suddenly warmed, 
 it flies into pieces like glass, and clearly shows a structure highly crystalline, instead of malleable. The 
 alloy has no trace of the red color of the copper, but it is quite white, susceptible of an exquisite polish, 
 and being little disposed to tarnish it is most perfectly adapted to the reflecting speculums of telescopes 
 and other instruments, for which purpose it is alone used. 
 
 Copper, when combined in the same 'proportions with a different metal, also light-colored and fusible, 
 namely two parts of copper with one of zinc, (which latter metal is of a bluisli-wdiiie, and crystalline, 
 whereas tin is very ductile,) makes an alloy of entirely opposite character to the speculum metal ; 
 namely, the soft yellow brass, which becomes by hammering very elastic and ductile, and is very easily 
 cut and filed. 
 
 Again, the same proportions, namely, two parts of copper and one of lead, make a common inferior 
 
 * Dr. Turner’s Chemistry, Seventh Edition, 1841, p. 558. + Ibid., p. 559. 
 
 t hi this alloy the antimony fulfils another service besides that of imparting hardness: antimony somewhat expands on 
 cooling, whereas lead contracts very much, and the antimony therefore, within certain limits, compensates for this contrac 
 tion, and causes the alloy to retain the full size of the moulds. 
 
 Sometimes from motives of economy the neighboring parts of machinery are not wrought accurately to correspond one 
 with the other, but lead is poured in to fill up the intermediate space, and to make contact. As around the brass nuts in 
 the heads of some screw-presses, in the guides or followers for the same, and some other parts of either temporary or per- 
 manent machinery. Antimony is quite essential in all these cases to prevent the contraction the lead alone would sustain, 
 and which would defeat the intended object, as the metal would otherwise become smaller than the space to be tilled. 
 
 § A little tin is commonly introduced into types, and likewise copper in minute quantity; iron and bismuth are also 
 spoken of; the last is said to be employed on account of its well-known property of expanding in cooling, so as to cause the 
 types to swell in the mould, and copy the face of the letter more perfectly ; but although i find bismuth to have been thus 
 used, it appears to be neither common nor essential in printing types. 
 
390 
 
 METALS AND ALLOYS. 
 
 metal, called pot-metal, or cock -metal, from its employment in those respective articles. This alloy is 
 much softer than brass, and hardly possesses malleability ; when, for example, the beer-tap is driven 
 into the cask, immediately after it has been scalded, the blow occasionally breaks it in pieces, from its 
 reduced cohesion. 
 
 Another proof of the inferior attachment of the copper and lead, exists in the fact that if the moulds 
 are opened before the castings are almost cold enough to be handled, the lead will ooze out, and appear 
 on the surface in globules. This also occurs to a less extent in gun-metal, which should not, on that 
 account, be too rapidly exposed to the air ; or the tin strikes to the surface, as it is called, and makes it 
 particularly hard at those parts, from the proportional increase of the tin. In casting large masses o( 
 gun-metal, it frequently happens that little hard lumps, consisting of nearly half tin, work up to the 
 surface of the runners or pouring places, during the time the metal is cooling. 
 
 In brass, this separation scarcely happens, and these moulds may be opened whilst the castings are 
 rod.-hot, without such occurrence ; from which it appears that the copper and zinc are in more perfect 
 chemical union, than the alloys of copper with tin, and with lead. 
 
 Malleability and ductility of alloys. — The malleability and ductility of alloys are in a great measure 
 referable to the degrees in which the metals of which they are respectively composed possess these 
 characters. 
 
 Lead and tin are malleable, flexible, ductile, and inelastic, whilst cold, but when their temperatures 
 much exceed about half way towards their melting heats, they are exceedingly brittle and tender, 
 owing to their reduced cohesion. 
 
 The alloys of lead and tin partake of the general nature of these two metals ; they are flexible when 
 cold, even with certain additions of the brittle metals antimony and bismuth, or of the fluid metal 
 mercury ; but they crumble with a small elevation of temperature, as these alloys melt at a lower 
 degree than either of their components, to which circumstance we are indebted for the tin solders. 
 
 Zinc, when cast in thin cakes, is somewhat brittle when cold, but its toughness is so far increased 
 when it is raised to about 300° Fahr. that its manufacture into sheets by means of rollers is then admissi- 
 ble ; it becomes the malleable zinc, and retains the malleable and ductile character, in a moderate 
 degree, even when cold, but in bending rather thick plates it is advisable to warm them to avoid frac- 
 ture ; when zinc is remelted it resumes its original crystalline condition* 
 
 Zinc and lead will not combine without the assistance of arsenic, unless the lead is in very small 
 quantity ; the arsenic makes this and other alloys very brittle, and it is besides dangerous to use. Zinc 
 and tin make, as may be supposed, somewhat hard and brittle alloys, but none of the zinc alloys, except 
 that with copper to constitute brass, are much used. 
 
 Gold, silver, and copper, which are greatly superior in strength to the fusible metals above named, 
 may be forged either when red-hot or cold, as soon as they have been purified from their earthy mat- 
 ters, and fused into ingots; and the alloys of gold, silver, and copper are also malleable, either red-hot 
 nr cold.f 
 
 Fine, or pure gold and silver, are but little used alone ; the alloy is in many cases introduced less 
 with the view of depreciating their value than of adding to their hardness, tenacity, and ductility ; the 
 processes which tire most severely test these qualities, namely, drawing the finest wires and beating 
 gold and silver leaf, are not performed with the pure metals, but gold is alloyed with copper for the 
 red tint, with silver for the green, and with both for intermediate shades. Silver is alloyed with copper 
 only, and when the quantity is small its color suffers but slightly from the addition, although all its 
 working qualities are greatly improved, pure silver being little used. 
 
 The alloys of similar metals having been considered, it only remains to observe that when dissimilar 
 metals are combined, as those of the two opposite groups — namely, the fusible lead, tin, or zinc, with 
 the less fusible copper, gold, and silver — the malleability of the alloys when cold is less than that of the 
 superior metal; and when heated barely to redness, they fly in pieces under the hammer; and there- 
 fore, brass, gun-metal, Ac., when red-hot, must be treated with precaution and tenderness. Muntz’s 
 patent metal, which is a species of brass and is rolled red-hot, appears rather a contradiction to this ; 
 but in all probability this alloy, like the ingots of cast-steel, requires at first a very nice attention to the 
 force applied. It will be also remembered the action of rollers is more regular than that of the ham- 
 mer ; and soon gives rise to the fibrous character, which, so far as it exists in metals, is the very ele- 
 ment of strength when it is uniformly distributed throughout their substance. This will be seen by the 
 inspection of the relative degrees of cohesion possessed by the same metal when in the conditions of 
 the casting, sheet, or wire, and to which quality or the tenacity of alloys we shall now devote a few 
 lines. 
 
 Strength or cohesion of alloys. — The strength or cohesion of the alloys, is in general greatly superior 
 to that of any of the metals of which they are composed. 
 
 All nice attempts at proportion, are, however, entirely futile, unless the metals are perfectly pure ; 
 for example, it is a matter of common observation that for speculums, a variable quantity of from seven 
 and a half to eight and a half ounces of tin is required for the exact saturation ot every pound of cop 
 per, and upon which saturation the efficiency of the compound depends ; bells of exactly similar quality 
 sometimes thus require the dose of tin to vary from three and a half to five ounces to the pound of 
 copper, according to the qualities of the metals. 
 
 Fusibility of alloys. — In concluding this slight view of some of the general characters of alloys, it re- 
 mains to consider the influence of heat, both as an agent in their formation, and as regards the degree 
 in which it is required for their after fusion ; the lowest available temperature being the most desirable 
 hi every such case. 
 
 “ Metals do not combine with each other,” says Dr. Turner, “in their solid state, owing to the influence 
 
 * It is considered that most of the sheet zinc contains a very little lead. 
 + Gold alloyed with copper alone is not very malleable when hot. 
 
METALS AND ALLOTS. 
 
 39 
 
 ct chemical affinity being counteracted by the force of cohesion. It is necessary to liquefy at least ona 
 of them, in which case they always unite, provided their mutual attraction is energetic. Thus, brass is 
 formed when pieces of copper are put into melted zinc ; and gold unites with mercury at common tem- 
 peratures by mere contact.” 
 
 The agency of mercury in bringing about triple combinations of the metals, both witli and without 
 heat, is also very curious and extensive. Thus, in water-gilding , the silver, copper, or gilding metal, 
 when chemically clean, are rubbed over with an amalgam of gold containing about eight parts of 
 mercury ; this immediately attaches itself, and it is only necessary to evaporate the mercury, which 
 requires a very moderate heat, and the gold is left behind. Water-silvering is similarly accom- 
 plished. 
 
 Cast-iron, wrought-iron, and steel, as well as copper and many other metals, may be tinned in a 
 similar manner. An amalgam of tin and mercury is made so as to be soft and just friable ; the metal 
 to be tinned is thoroughly cleaned either by filing or turning, or if only tarnished by exposure, it is 
 cleaned with a piece of emery-paper or otherwise, without oil, and then rubbed with a thick cloth 
 moistened with a few drops of muriatic acid. A little of the amalgam then rubbed on with the same 
 rag, thoroughly coats the cleaned parts of the metal by a process which is described as cold-tinning ; 
 other pieces of metal may be attached to the tinned parts by the ordinary process of tin-soldering. 
 
 In making the tinned-iron plates, the scoured and cleaned iron plates are immersed in a bath of pure 
 melted tin ; covered with pure tallow, the tin then unites with every part of the surfaces ; and in the 
 ordinary practice of tinning culinary vessels of copper, pure tin is also used. The two metals, however 
 must then be raised to the melting heat of tin ; but the presence of a little mercury enables the process 
 to be executed at the atmospheric temperature, as above explained. 
 
 In Mr. Mallett’s recently patented “ processes for the protection of iron from oxidation and corrosion, 
 and for the prevention of the fouling of ships,” one proceeding consists in covering the iron with zinc. 
 
 The ribs or plates for iron ships are immersed in a “ cleansing bath” of equal parts of sulphuric or 
 muriatic acid and water, used warm ; the works are then hammered, and scrubbed with emery or sand, 
 to detach the scales and to thoroughly clean them ; they are then immersed in a “ preparing bath” of 
 equal parts of saturated solutions of muriate of zinc and sal-ammoniac, from which the works are trans- 
 ferred to a fluid “metallic bath,” consisting of 202 parts of mercury and 1292 parts of zinc, both by 
 weight ;* to every ton weight of which alloy is added about one pound of either potassium or sodium, 
 (the metallic bases of potass and soda,) the latter being preferred. As soon as the cleaned iron works 
 have attained the melting heat of the triple alloy, they are removed, having become thoroughly coated 
 with zinc. 
 
 The affinity of this alloy for iron is, however, ^o intense, and the peculiar circumstances of surface as 
 induced upon the iron presented to it by the preparing bath are such, that care is requisite lest by too 
 long an immersion the plates are not partially or wholly dissolved. Indeed, where the articles to be 
 covered are small, or their parts minute, such as wire, nails, or small chain, it is necessary before im- 
 mersing them to permit the triple alloy to dissolve or combine with some wrought-iron, in order that 
 its affinity for iron may be partially satisfied, and thus diminished. At the proper fusing temperature 
 of this alloy, which is about 680° Fahr., it will dissolve a plate of wrought-iron of an eighth of an inch 
 thick in a few seconds. 
 
 The palladiumizing process . — The articles to be protected are to be first cleansed in the same way 
 as in the case of zincing ; namely, by means of the double salts of zinc and ammonia, or of manganese 
 and ammonia ; and then to be thinly coated over with palladium, applied in a state of amalgam with 
 mercury. 
 
 In the opinion of eminent chemists and metallurgists, all the metals, even the most refractory, which 
 nearly or quite refuse to melt in the crucible when alone, will gradually run down when surrounded by 
 some of the more fusible metals in the fluid state ; in a manner similar to the solution of the metals in 
 mercury, as in the amalgams, or the solutions of solid salts in water. The surfaces of the superior metals 
 are, as it were, dissolved, washed down, or reduced to the state of alloys, layer by layer, until the entire 
 mass is liquefied. 
 
 Thus nickel, although it barely fuses alone, enters into the composition of German silver by aid of the 
 copper, and whilst it gives whiteness and hardness, it also renders the mixture less fusible. Platinum 
 combines very readily with zinc, arsenic, and also with tin and other metals ; so much so, that it is 
 dangerous to melt either of those metals in a platinum spoon, or to solder platinum with common tin 
 solder, which fuses at a very low temperature; although platinum is constantly soldered with fine gold, 
 the melting point of which is very high in the scale. Again, the circumstances that some of the fusible 
 bismuth alloys melt below the temperature of boiling water, or at less than half the melting heat of tin, 
 their most fusible ingredient, show that the points of fusion of alloys, are equally as difficult of explana- 
 tion or generalization as many other of the anomalous circumstances concerning them. 
 
 This much, however, may be safely advanced, that the alloys, without exception, are more easily 
 fused than the superior metal of which they are composed ; and extending the same view to the relative 
 quantities of the components, it may be observed that the hard solders for the various metals and 
 alloys are in general made of the self-same material which they are intended to join, but with small 
 additions of the more fusible metals. The solder should be, as nearly as practicable, equal to the metal 
 on which it is employed, in hardness, color, and every property excejtt fusibility ; in which it must excel 
 just to an extent that, when ordinary care is used, will avoid the risk of melting, at the same time, both 
 the object to be soldered and likewise the softer alloy or solder by which it is intended to unite its 
 parts. 
 
 It would appear as if every example of soldering in which a more fusible alloy is interposed, were 
 also one of superficial alloying. Thus, when two pieces of iron are united by copper, used as a solder 
 
 Being in the proportion of one atom of mercury to forty atoms of zinc. 
 
392 
 
 METALLURGY. 
 
 it seems to be a natural conclusion that each surface of the iron becomes alloyed with the copper ; and 
 that the two alloyed surfaces are held together from their particles having been fused in contact, and 
 run into one film. It is much the same when brass or spelter solder is used, except that triple alloys 
 are then formed at the surfaces of the iron, and so with most other instances of soldering. 
 
 And in cases where metallic surfaces are coated by other metals, the latter being at the time in a 
 state of fusion, as in tinned-iron plates and silvered copper ; may it not also be conceived, that between 
 the two exterior surfaces which are doubtless the simple metals, a thin film of an alloy compounded of 
 the two does in reality exist ? And in those cases in which the coating is laid on by the aid of mercury, 
 and without heat, the circumstances are very similar, as the fluidity of mercury is identical with the 
 ordinary state of fusion of other metals, although the latter require higher temperatures than that of our 
 atmosphere. 
 
 When portions of the same metal are united by partial fusion, and without solder, as in the process 
 described as burning together, and more recently known as the “ autogenous ” mode of soldering, no alloy 
 is formed, as the metals simply fuse together at their surfaces. 
 
 Neither can it be supposed that any formation of alloy can occur where the one metal is attached to 
 the other by the act of burnishing on with heat, as in making gilt wire, but without a temperature suf- 
 ficient to fuse either of the metals. The union in this case is probably mechanical, and caused by the 
 respective particles or crystals of the one metal being forced into the pores of the other, and becoming 
 attached by a species of entanglement, similar to that which may be conceived to exist throughout solid 
 bodies. This process, almost more than any other in common use, requires that the metals should be 
 perfectly or chemically clean ; for which purpose they are scraped quite bright before they are burn- 
 ished together, so that the junction may be next approaching to that of solids generally. 
 
 And, lastly, when metals are deposited upon other metals by chemical or electrical means, the addi- 
 tion frequently appears to be a detached sheath, and which is easily removed ; indeed, unless the metal 
 to be coated is chemically clean, and that various attendant circumstances are favorable, the sound and 
 absolute union of the two does not always happen, even when carefully aimed at. 
 
 METALLURGY. A word derived from the Greek, signifying the art of working metals, or the art 
 by which metals are produced from their ores. 
 
 Metals constitute a well-known class of substances, distinguished by characteristics which every one 
 recognizes. They are considered as elementary matter by chemists, because chemistry has failed, up 
 to the present time, to resolve any one of them into more simple forms of matter ; they may, therefore, 
 be regarded as an aggregation of elementary atoms, held together by the force of cohesion. Metals are 
 popularly recognized as heavy matter, of great tenacity ; of a peculiar metallic lustre, which it is diffi- 
 cult to describe, but which is easily recognized. With one exception, namely, quicksilver, all the metals 
 are solid at ordinary temperatures ; they are all capable of liquefaction, and even volatilization, at 
 higher temperatures, the degree of heat being a different one in every instance. Metals, as a class, are 
 characterized by a higher specific gravity than almost all other matter ; they are distinguished by 
 opacity, from which rule only gold and silenium are excepted. The capacity of conducting heat and 
 electricity is possessed by metals to a high degree of perfection. 
 
 Malleability is the property of metals to change their form permanently, under a certain pressure. 
 The most important considerations for our present purposes are, the chemical qualities, the fusibility of 
 metals, their affinity for other matter, and their affinity among themselves. 
 
 Fusibility . — The degree of heat at which metals assume the solid or the fluid state is their fusibility. 
 
 Mercury melts at 39° 
 
 “ boils “ 600° 
 
 Tin melts “ 420° 
 
 Lead “ “ 600° 
 
 Zinc “ “ 666° 
 
 Silver melts at 1860o 
 
 Gold “ “ 1983° 
 
 Cast-iron “ “ 2700° 
 
 Platinum" “ 4561° 
 
 The affinity of the metals for oxygen forms a very important item in our investigations. The oxides of 
 mercury, silver, gold, platinum and the platinum metals, part with their oxygen by the mere application 
 of heat. The following oxides of metals retain their oxygen at any temperature ; they require the 
 addition of carbon or hydrogen in order to expel their oxygen : lead, copper, bismuth, antimony, 
 chromium, arsenic, nickel, cobalt, iron, tin, zinc. Most of these oxides may be deprived of their oxygen 
 by carbon only, others by carbon and hydrogen, and some may be reduced by hydrogen only. Hydrogen 
 reduces all these oxides, but with most of them the point of reduction is so low as to leave the metal 
 in the form of a fine powder, which oxidizes as soon as it is exposed to the atmosphere. Iron, copper, 
 nickel, chromium, and other metals cannot be reduced by hydrogen, on account of the low heat by 
 which the process is accomplished. Antimony, arsenic, tin, zinc, lead, mercury, and all the alkaline 
 metals may be reduced by hydrogen. The facility with which metals oxidize is also of importance 
 in metallurgical operations. Lead, copper, bismuth, antimony, chromium, and arsenic do not decompose 
 water at any temperature, but are easily oxidized by atmospheric air. Nickel, cobalt, iron, tin, zinc, 
 manganese, decompose water easily at a red heat. All the terrifiable metals, such as aluminum, and 
 we may add silicon, are easily oxidized at a higher heat, and their oxides readily reduced in the pres- 
 ence of carbon, and of such other metals as these metals can combine with. The alkaline metals 
 oxidize most readily under all conditions, and their oxides are easy of reduction in the presence of other 
 metals, such as lead, antimony, and others with which the alkaline metals may combine. Besides the 
 combination of the metals with oxygen, their union with other matter, such as sulphur, phosphorus, 
 carbon, Ac., is of high interest. Most of the metals combine readily with sulphur, such as iron or 
 lead ; others are not so easily disposed to enter into that combination, as zinc and gold. The affinity 
 of sulphur for the metals and carbon, and the mode and conditions under which these combinations 
 may be separated, forms a very important part of the metallurgist’s knowledge. Of the same import- 
 ance as the sulphur combinations are those of phosphorus ; which combinations are in most cases more 
 
METALLURGY. 
 
 393 
 
 difficult of separation than all other or similar compounds. Of equal importance to the smelter of 
 metals, is the relation of the metals among themselves ; it is not so much the nature and qualities of 
 these combinations, as the conditions under which the metals combine and separate, which interest him. 
 
 The art of smelting consists in the knowledge of the nature of metals, their fusibility and relation to 
 other matter. It is not so much the specific qualities of metals which interest the metallurgist, as the 
 mode of manufacturing the metals from their native ores. To produce metal from ore, the first condi- 
 tion is to expose the ore to such a high heat as will melt the metal. Gold, mercury, and the platinum 
 metals may be produced in this way to a certain extent. All or most of the metals in nature are 
 copibined with other matter, such as oxygen, sulphur, phosphorus ; to remove the oxygen, we add to 
 the ore matter which has a greater affinity for oxygen than the metal, at or near that degree of heat by 
 which the metal melts: carbon is the most generally in use, hydrogen serves in some cases, and metals 
 in others. Metals and sulphur, or other matter, may be roasted, and the metal resolved into an oxide ; 
 but if sucli process is not practicable, the sulphuret or phosphuret, <Src., is melted along with another 
 metal, such as sulphuret of lead or copper with metallic iron, where always that condition is complied 
 with, namely, that the newly formed metal is more fusible than the newly formed sulphuret. Metallic 
 ores are in most cases a mechanical mixture of the metal in its pure state, as gold ores ; or a mixture of 
 the oxide of metal and other matter, such as is the case in clay — iron — stone : or the ores are a chemical 
 combination of one sulphuret of metal with other sulphurets of metal, as copper-pyrites in connection 
 with iron-pyrites, to which, frequently, silex or clay is added in admixture. The prevailing principle 
 in all metallurgical operations is, with but few exceptions, the transformation of all ores into metallic 
 oxides, and the reduction of these oxides by carbon. Where the metallic oxides are incorporated with 
 matter, such as silex, alumina, or lime, which cannot be reduced at those temperatures and under those 
 conditions by which the metals melt and are reduced themselves, that matter would prevent the agglu- 
 tination of the metallic globules, and permit but a small portion of the metal to separate from it, even if 
 all other conditions of the reducing process are fulfilled ; this foreign matter forms an inclosure to the me- 
 tallic particles. This inclosure is to be destroyed, which, in many cases, can be done by heat simply ; such 
 is the case with some copper ores, where a certain portion of iron is present. In other cases it requires 
 the addition of such matter to the ore which will combine with the impurities of it, melt with it, and lib- 
 erate the metal. This latter part of the science of metallurgy is the most difficult to obtain, and exerts 
 the most influence upon the practical results of the operation. This branch of our investigation it is be- 
 yond the limits of this article to explore fully, we can furnish but a faint outline of the principles involved. 
 
 The formation of fusible slags is accomplished by smelting an oxide of one metal together with the 
 oxide of another, or these oxides together with silex. These combinations are subject to the laws of 
 affinity developed by chemistry. They depend upon the quantity of the oxides, their degree of oxida- 
 tion, their relative position in the scale of affinity, and the conditions under which the oxides meet. The 
 most prevalent in these combinations are the silicates, or a vitrification of a metallic oxide with silex. 
 Either mixed to a silicate, or one mixed to the other, are frequently found the carbonates, chlorides, 
 sulphates, fluates, and other salts, which form in all cases a more or less fusible slag. The nature of the 
 operation requires the formation of a fusible slag as most advantageous to the process. In practice, this 
 principle is frequently modified, on account of the quality of the metal to be produced, or, more generally, 
 for reasons of economy. Silex and alumina are the most pervading admixtures to metallic ores ; these 
 are vitrified by all the alkalies and alkaline earths, by protoxides of metals, and the oxides of metals. 
 The fusibility of these combinations is in the following order : alkalies, alkaline-earths, protoxides, and 
 peroxides. A mixture of various oxides or alkalies is more fusible than that of but one alkali or oxide, 
 with silex or alumina ; the greater the number of these vitrifying elements, the more fusible and homo- 
 geneous is the slag ; the greater the affinity between the composing parts of a slag, the easier it melts. 
 The laws involved in this question may be abstracted from chemistry, always, however, with due 
 regard to the' temperature by which the operation is performed. 
 
 Preparatory metallurgical operations. — Some metallic ores may be made to yield their metal by 
 merely crushing and washing the ore — such are the gold and platinum ores. Other ores may be smelted 
 without any preparation or addition of fluxes ; to this class belong a large portion of the copper ores, 
 some iron ores, and most of the lead ores. Some ores require simple roasting, others stamping and 
 roasting, before they are ready for the smelting furnace. Almost all the ores, to be smelted, require tlv 
 addition of fluxes to make the operation profitable. The manipulations in the smelt-works avr, divided 
 into the preparation of fuel, preparation of ore, and smelting. The first we consider as too extended for 
 the limits of this article, (see Iron,) and confine the subject to the description of the two latter pro- 
 cesses. Preparation of ore is again divided into dressing, roasting, crushing, and washing of ore. 
 
 Pressing of ore. — An imperfect picking or sorting of ore is generally performed in the mines; but 
 as a distinct separation and classification cannot be expected in this place, valuable ores are once more 
 picked and cleaned above-ground with greater care than it could be done in the mine. Iron ores, and 
 such ores which cannot bear such expense, are used directly from the mine, without further sorting. 
 Gold ores are necessarily assorted before they are brought to the mill ; the same operation is performed 
 on silver ores. If there are pieces among the ore which contain no metal at all, they are thrown away ; 
 also such as are so poor as not to pay the expenses of the subsequent operations. 
 
 Stamping of ore. — If the mixture of metallic ore and impurities is very intimate, and are the impuri- 
 ties of such a nature as to make smelting difficult, they are moved to the stamping-mill, where the 
 ores are crushed, broken into a more or less fine sand, and washed. Crushing is performed by ma- 
 chinery called a stamping-mill. 
 
 In Fig. 2805 a mill of this kind is represented in plan, and in Fig. 2806 in elevation. The machine 
 represented in the engravings has been erected in Virginia during the last year. 
 
 For the crushing of gold ore there are 30 stampers connected with the engine, which is of 40 horse- 
 power. These stampers are scantlings of white-oak wood, 6 feet long, and 6X6 inches thick. Each 
 wooden stamper is provided at its lower end with a cast-iron pestle, (stamper-head,) weighing from 2 
 
394 
 
 METALLURGY. 
 
 to 2i cwts. each. These stamper-heads are made of the finest and hardest kind of cast-iron, such iro« 
 as chilled rollers are made of, and are cast in heavy iron chills, so as to harden the whole surface of the 
 head. These heads are fastened to the wooden helve by a wrought-iron tang of two inches square 
 iron, cast in into the head and sunk into the centre of the wood, where it is secured by wrought-iron 
 
 hoops laid around the lower end of the helve. The SO stampers are divided into 3 sets of 5 each ; these 
 5 stampers work into one trough — that is, the whole length of the trough is divided into 6 compart- 
 ments, of which each forms a set or battery. Each battery has its own feeding apparatus ; this is a 
 
 Into this hopper the ore is carried as it comes 
 2807. 
 
 large, wooden, fixed hopper, as shown in Fig. 2807. 
 from the hive. It discharges the ore in the middle 
 of the battery or set of five stampers, the middle 
 stamper drawing as much ore as, with the assist- 
 ance of the two stampers on each side, it can crush. 
 
 The bottom of each trough is provided with a cast- 
 iron plate; the stampers, however, never touch tliis 
 plate. Upon this bed-plate a bed of quartz is laid, 
 and kept so that always from 2 to 4 inches high of 
 partly crushed quartz is in the bottom of each bat- 
 tery. This bottom of rocky matter protects the iron 
 bottom, the stampers, and the whole machinery 
 against premature destruction. Each battery is in- 
 closed by a trough made of cast-iron plates, reach- 
 ing about 7 inches high above the bottom plate. 
 
 The woodwork to which these plates are fastened is higher, and reaches up to 12 or more inches. Each 
 battery is provided witli two sieves, or grates, shown by A ; these are made of sheet-iron, or sheet-cop- 
 per, pierced with holes, or they are made of brass- wire gauze, tweeled, in which wire and spaces are 
 each about of an inch. Round holes punched in plates ought to be or -Jg of an inch in diameter. 
 These sieves are 8 inches square, fastened vertically at each end of the trough, about 4 inches or 3£ 
 inches above the bottom. The size and form of the holes in the sieves decide the size of the grains of 
 sand made, for all grains which cannot pass these holes are returned to the stamps. 
 
 Tliis stamping-machine crushes and washes the ore in the mean time, each stamper receiving 2J 
 gallons of water per minute. Where ores are stamped dry, the breast-plate and sieves at each battery 
 can be dispensed with. The yield of the machine is about 1000 bushels of quartz converted into fine 
 sand fit for amalgamation in 12 hours, each pestle making from 90 to 100 strokes per minute, having 
 10 or 11 inches lift. The water in the trough ought to be always high enough to prevent splashing, 
 and loss of good mineral. There is a diversity of opinion respecting the construction of stamping- 
 machines, many machines being now built entirely of cast-iron. We are not aware that any superior 
 results have been achieved by cast-iron machines. It is against the practice and principles of mechanics 
 to build machines which work by concussion of an almost inelastic material such as cast-iron. Wooden 
 machines of this kind are, in the first place, cheaper, and, if well built, are more durable and of greater 
 effect than cast-iron structures. 
 
 Gold ores are stamped to liberate the metallic gold inclosed by rocky matter. Lead ores, copper 
 ores, silver ores, &c., are stamped to wash off the gangue. Rocky matter is of a smaller specific 
 gravity than the metallic ores generally are, particularly the sulphurets. When an ore is pulverized, 
 and a current of water passed through the trough containing it, the sand and clay, limestone, <fcc , will 
 pass off readily in coarse grains, because its gravity is greatly diminished in water : such grains are car- 
 ried off by the slightest current. Metallic substances more heavy than quartz or rocky matter, will not 
 move until reduced to a certain size, when the particles will follow the current by adhesion, or be so 
 inconsiderable as to be carried off by the wash water. The current of water issuing from the stamps 
 will carry the rocky matter further than the metallic granules, and if the water and sand from the 
 stamps is led into a long wooden trough, the lightest particles will be found furthest off the stamps, and 
 the heaviest matter nearest to the mill. The size of the grains is regulated in the mill, chif fly by the 
 height of the grating or sieve above the bottom of the trough or stamper-bed ; further by the size of the 
 
METALLURGY. 
 
 895 
 
 holes in the sieve ; by the amount of water ; by the lift of the stamps, weight of stamps, and particu- 
 larly by the kind of bottom used. If the bottom is too hard or thin, the mill stamps coarsely ; and if the 
 rock bottom is too thick, it stamps too fine. 
 
 Other means of grinding or crushing ore are millstones, of considerable weight and size. In Fig. 
 2808 a mill of this kind is represented. A vertical shaft, to which a cross shaft and two millstones of 
 4 or 5 feet diameter are appended, revolves slowly around itselt, making from 3 to five revolutions per 
 minute. This shaft carries with it the two head-stones, which revolve around the vertical axis, and in 
 the mean time around their own axis, running upon a third millstone, which is laid horizontal, and fixed 
 upon the floor of the millhouse. These stones are of hard material, either of granite, gneiss, trap, or 
 some other tenacious hard rock. Such mills are chiefly used for grinding clay, fire-clay, or kaolin in poi 
 
 2808. 
 
 celain manufactories. Similar mills are exclusively employed in North Carolina for crushing gold ores, 
 also to some extent in Virginia ; they are there entirely constructed of iron, or at least the facing, or 
 grinding part of it is made of cast-iron ; and are here called Chilian-mills. These mills show one ad- 
 vantage to the stamper-mills; that is, they may be made to grind the ore very fine ; and where that is 
 necessary, as it is with many gold ores, these mills are advantageous. But there is one serious draw- 
 back to these machines : they require much power in proportion to their effect, and much room. A 
 strong mill of this kind requires from 4 to 6 horse-power, with which it will grind from 40 to 50 bushels 
 of ore in 12 hours, that is, ten bushels to a horse-power. One horse-power will drive one stamper in a 
 stamp-mill, and that stamper will crush at least 30 bushels in the same time, — a consideration which 
 is of importance where wages, power, and time are valuable. Other crushing apparatus, such as common 
 mills, in the form of grist-mills, crushing rollers, and similar machinery, are not in use in this country, at 
 least not to any extent. 
 
 Washing of ores . — Ores which contain a considerable amount of clay, lime, sand, and other impurities 
 which may be injurious to the smelting operation, are washed in an abundance of water, so as to carry 
 off the light particles and retain the heavy metallic matter. The simplest form of a washing apparatus, 
 such as is used for washing impure iron ores, is represented in Fig. 2809. A is a long wooden trough of 
 from 20 to 50 feet long, 12 inches wide in 
 the bottom, and 6 or 8 inches high. This 
 trough is a little inclined to the horizon, so 
 as to afford a gentle current. At the up- 
 per end a strong current of water is let 
 into it, from a weir or an elevated reser- 
 voir, which flows down the channel at a 
 rapid rate. At the entrance of the water 
 a laborer throws in, at intervals, a shovel- 
 full of unclean ore, under the current from 
 the spout of the pool. The water in fall- 
 ing upon the ore moves first the small 
 and light particles, which are carried 
 downwards to the valves B and C. The 
 light, floating particles are carried over 
 these valves, and are discharged at 
 the end of the trough. The heavier particles near the bottom are carried to the valves and pass 
 through these, the coarse through the opening B, and the smaller through C, forming heaps below, 
 from which the remaining light impurities flow off. This apparatus is simple, effective, and may 
 be applied in all instances where washing is to be done. Various modes and machines are used 
 in Europe to remove the earthy matter from the ore by washing. Complicated sifting machines 
 are employed, the grilles or step-washings of Hungary, percussion-tables, shaking-tables, German-chests, 
 sleeping-tables, swing-sieves, and a host of other machines, all of which are of no use to us ; these ma- 
 chines work too slow, absorb too much labor, and are not advantageous to our modes of working. The 
 above wash apparatus, properly modified in particular cases, is all-sufficient for washing any kind of 
 ore, and purifying it so far as necessary. 
 
 Boasting of ores . — This process is sometimes performed on the ores when brought from the mine, as 
 
BOG 
 
 METALLURGY. 
 
 is the case with iron ore, or it is performed after the ores are crushed, wdiich is the way cf working sil 
 ver ores in North Carolina. The principle involved in this operation is to drive off all that volatile mat- 
 ter from the ore which may be dissipated by heat ; such as water, carbon, sulphur, phosphorus, chlorine, 
 arsenic, zinc, &c. The consequence of this operation, if well performed, is in all cases, with but few 
 exceptions, the oxidation of the remaining metals to their highest degree ; a condition in which the ores 
 are most easily worked, and reduced by carbon to the metallic state. Roasting is performed in this 
 country almost exclusively in the open air; experiments made on roasting ovens met in but few instan- 
 ces with success. There is no doubt but that roast ovens are more economical in the use of fuel than 
 heaps in the open air, but the ovens require more labor ; and as fuel is cheap with us, labor high, the 
 reverse of what they are in Europe, it appears to be natural to follow those modes of working which 
 tend to lessen cost, and do the work in the cheapest way. In Fig. 2810 a roast-heap is represented in 
 section. These heaps are often round, but in most cases are mounds of from 25 to 50 and more feet 
 long. The operation consists in spreading over an area of a certain length, and from 8 to 20 feet wide, 
 sticks of fire-wood, which may be of an indifferent 
 kind and form. The spaces between the sticks are 
 filled up by small wood, chips, or any kind of fuel, 
 providing, however, sufficient spaces for the access 
 of air from below. The coarser pieces of ore are 
 now spread over this grating of wood, and a layer 
 of from 8 to 12 inches levelled over it; on this ore 
 fine charcoal, braise, is spread about 2 inches thick. 
 
 Instead of fine charcoal, mineral coal slack may be 
 used to advantage, or wood chips, or in fact any 
 fuel free of injurious matter, such as sulphur, phos- 
 phorus, &c. Ore is now piled again upon this coal, and the operation of laying coal and ore in succes- 
 sive layers repeated until that height of the heap is reached which is calculated to be most ad- 
 vantageous in this particular instance. One inch thick of coal is generally considered sufficient for one 
 foot high of ore, exclusive of the foundation of wood. The ore is broken into uniform sizes, of from 2 to 3 
 inches thick. Fire is kindled in the lower parts of the heap, which to conduct to advantage requires 
 considerable skill, sagacity, and industry. The chief object in this operation being the dissipation of 
 volatile matter, it is evident that the melting of any particles of the ore is to be prevented, for from 
 such melted ore no degree of heat will separate the injurious matter effectually. The conducting of 
 the degree of heat in the roasting heap is therefore an operation liable to injure the ore instead of bene- 
 fiting it. Ores which melt readily, such as impure iron ores, silver and lead ores, pyrites of all kinds, 
 require oore than common watchfulness to insure success in the operation. 
 
 Fi& 2911 represents the section of a reverberatory furnace for roasting schliech of lead ore in Ger- 
 man"; These ores contain much sulphuret of zinc, and resemble our silver ores in Virginia and North 
 
 2810. 
 
 Carolina, for which reasons we allude particularly to this furnace. Fig. 2812 is the diawmg of an ele- 
 vation of that furnace, showing it to be a double furnace ; and Fig. 2813 is the plan of half the furnace, 
 or one single furnace. In these several figures, a is the furnace or fireplace ; b, a chimney leading to 
 
METALLURGY. 
 
 397 
 
 the condensing chambers cc, in which the evaporated metals, as zinc, arsenic, Ac., are conducted ; d is 
 the stack for the escape of the burnt gases and smoke ; e‘ is the charging door ; f the drying chamber 
 for expelling the water from the ore ; g is the hopper or charging orifice ; h the hearth of the furnace ; 
 i channels for the escape of moisture from the ground ; n n’ are openings leading to the condensing 
 chambers. In each of these furnaces nearly half a ton of ore is charged at a time, which takes from a 
 to 12 hours work to be roasted; much zinc delays the process. About two thirds of a cord of wood is 
 required to perform one heat. If well constructed and properly managed, these furnaces work exceed- 
 ingly well, but require a great deal of labor. 
 
 As remarked before, roasting ovens are more economical in the use of fuel than heaps in the open 
 air ; this advantage, however, is balanced by our having generally cheap fuel. These ovens are liable 
 to do imperfect work ; the access of air, which is the chief oxidizing agent, is not so freely admitted as 
 in heaps. In ovens the advantageous access of watery vapors is out of the question, which, as in the 
 case of heaps, are derived from the ground in such quantities and in such conditions as to be most advan- 
 tageous to the operation. Watery vapors afford in roasting the triple advantage of being a powerful 
 oxidizing element, in the mean time carrying off sulphur in the form of sulphuretted hydrogen, and assist- 
 ing in keeping the heat more uniform than it can be done without these vapors. The roasting in heaps 
 may be more expensive in some cases ; it certainly is more correct in principle than roasting in ovens. 
 
 Boasting in reverberatory furnaces may be considered an advantageous operation where sulphur, 
 arsenic, and such volatile matter is to be expelled which cannot well be removed in the yard by roast- 
 ing in heaps. These furnaces apply particularly where arsenic is to be driven off; but as no arsenical 
 ores are smelted in the Union, there is little use for reverberatory roast-ovens. At the copper smelt- 
 works roasting is done to a certain extent in the reverberatory, but it is not practised in any other in- 
 stance. This furnace suffers under the same disadvantage as the roast-oven ; the work performed by it 
 is expensive, because of the labor it requires to stir and shovel the ore. 
 
 Blast machines are auxiliaries in metallurgical operations. We refer to the article on “Iron" for in- 
 formation. 
 
 Assay of ores is a very important operation in smelt-works. Assaying is not only performed here to 
 ascertain the quantity of metal contained in the ore ; it is employed both for that purpose and for assay- 
 ing the metal to inquire what kind of metals and how much of each is contained in the samples pro- 
 duced in the smelting-furnace. Assays of gold ores are generally made by pounding the rock, convert- 
 ing it into a very fine powder, and washing the debris of rock away, which latter operation is. performed 
 in a sheet-iron pan. The remaining gold, after washing, is either taken up, amalgamated by quicksilver, 
 and the quicksilver expelled by heat, or, if the quantity is large, say one grain or more, it is weighed 
 in its native state. Experienced gold-washers will judge very near correctly how much one bushel of 
 ore will contain in gold by making one or more pan-washes. 
 
 Assays for ascertaining the quantity of a certain kind of metal in a specimen of ore, are in this in- 
 stance chiefly made in the dry way. If an ore is to be assayed for its contents in gold or silver, the 
 ore is finely powdered, sieved, and mixed with its three or fourfold weight of litharge. This litharge 
 must be free from any other metal but lead ; the common shop litharge is not quite safe in this respect, 
 and in case a correct assay is required, it is advisable to dry and roast sugar of lead ; the litharge de- 
 rived from it may be considered pure. The fine litharge and fine ore are well mixed, to which a very 
 little carbonate of soda may be added. If not much gold or silver is expected, but little lead is re- 
 duced in this process, which is regulated by the quantity of carbon mixed with it. In most cases, half 
 an ounce of lead will contain all the gold and silver in the ore ; one grain of charcoal produces SO 
 grains of lead ; if we want, therefore, 240 grains, or one half ounce of lead, we mix 8 grains of fine 
 charcoal powder with the above mixture of ore and litharge. The mixture is put in a dry and warm 
 crucible, covered by a little common salt, and a slab to prevent the falling in of coal, and then exposed 
 to a rapid heat in an air-furnace. One half hour’s heat will finish the operation ; the crucible is cooled, 
 broken, and the button of lead removed, washed, and cupelled. This button of lead, of half an ounce 
 weight, requires a cupel of half an ounce; better if one ounce. The cupel is a flat crucible, made of 
 bone-ashes, which, when the lead is heated in it, and in the mean time oxidized, it absorbs the oxide of 
 lead, just as a sponge absorbs water ; but this cupel will not absorb any metal in the metallic state. 
 Gold and silver have but little affinity for oxygen, and in heating the alloy of lead and other metals, 
 all other metals will be oxidized and absorbed by the cupel, while gold and silver remain in their pure 
 condition. When, in exposing the cupel in a muffle, or in a crucible, to a white heat, all the lead and 
 n+ber metal is oxidized and absorbed, a bright globule of gold or silver, or a mixture of both, remains ; 
 m the latter case the globule is analyzed in the humid way, to ascertain the quantity of either metal, 
 gold or silver. 
 
 Aext to the assays of gold or silver ores, are those of copper. These ores are pounded, roasted, and 
 mixed with from 1 5 to 100 per cent, of black flux. Black flux is prepared in mixing the powders of 
 equal parts of saltpetre and crude tartar together, heating this mass gently, and stirring it with a red- 
 hot iron ; the burnt powder is again pounded, sifted, and kept in a glass-stoppered bottle for occasional 
 use. The well-pounded and roasted ore is intimately mixed with its flux, put into a crucible, and heated 
 to a bright white heat in the shortest time. The resulting button of copper is broken out of the cooled 
 crucible and washed ; it is crude copper, and requires to be refined. This button is pounded in case it 
 is brittle; if not, it is melted in its original form, along with half its weight of black flux, to which a 
 little common salt or saltpetre is added ; the first, however, is preferable. While this crucible is melt- 
 mg, another is heated, in which a flux composed of black flux, common salt, and saltpetre, is contained ; 
 when the copper is thoroughly melted, and the second crucible hot, the flux melted, the copper is cast 
 from the first into the latter. By these means, metal and flux is mixed without running the risk of 
 losses, which inevitably follow if the crucibles are not shaken, or if they are stirred by an iron rod. If 
 the copper after this second assay is not fine, the process of refining is repeated once more, by which 
 time fine Conner is obtained. In Tiis operation, some copper remains always in the scoriae ; the lattei 
 
398 
 
 METALLURGY. 
 
 may be gathered together from all the smeltings and melted along -with some black flux, -which will 
 produce a small button of crude copper ; this is added to the first after it is refined, or added by ap- 
 proximating its value in copper. This last grain contains generally a great deal of iron, and looks like 
 iron. 
 
 Other ores than those mentioned are commonly not assayed in the smelt-works. Iron, lead, zinc, etc., 
 are of too little value ; they canuot bear these expenses. Tin we are not yet smelting, and in so far 
 have no need of assaying it. 
 
 Assaying forms a very important branch of the smelting establishment. In this country, owing to 
 the youth of metallurgical operations, most of the smelt-works are connected with the mines ; from 
 this rule the copper smelt-works are only excepted. For these reasons, the assay necessary to ascertain 
 the value of ore, in order to establish its price, is not in extensive use. When smelt-works shall be car- 
 ried on in their proper form, assaying of ore will be more generally executed. At present the assays 
 of ore are only used to ascertain the value of ore specimens, by which assays, as they allude but to a 
 small and in most cases a selected part of the ore, many illusory prices of ore are furnished, which de- 
 ceive the unwary. All assays made in the dry way are incorrect; they always furnish a smaller 
 amount of metal than the large operation ; if, however, the assays are conducted with uniform precision, 
 the loss in each case will be the same, and may be represented by a per-centage of the whole. The 
 second feature of the utility of the dry assay is its affording indications of the amount and nature of 
 the foreign admixtures to the ore : it furnishes a guide to the smelter at the furnace. Experiments as 
 to the mode of smelting an ore to the best advantage, can be made in the crucible with less expense 
 and greater facility than in the smelting furnace. A third advantage arising from the assay laboratory 
 ts the analysis of the manufactured metal in respect to its purity and contents of precious metals. 
 
 Assay in the humid way. — The chemical analysis of ore, or the assay in the humid way, is not of 
 much practical use to the metallurgist. If this assay is well performed, it furnishes an exact table of 
 the contents of an ore, of slags, and of metals ; but it requires more science and experience than com- 
 monly is at the disposal of the practical man, to make that use of an analysis winch frequently is 
 expected from it. The humid analysis furnishes the facts, the elements for the science of metallurgy ; 
 but the application of these facts is subject to more difficulties than at a superficial glance appear: it 
 is moreover a means of inducing young, speculative minds to a waste of time and money which may be 
 better employed than in chemical analysis. This department belongs to the scientific chemist : it is of 
 no use in the smelting-house. There is no doubt but the humid analysis furnishes the most correct esti- 
 mate of the contents of an ore, slag, and metal, but in all instances it is advisable to verify these results 
 by the dry assay, for there are innumerable instances where the portions of metal obtained in the analy- 
 sis cannot be yielded by the ore in the most perfect smelting operations. The assay comes nearer to 
 the practical result than the analysis. We cannot deny that the analysis furnishes principles upon 
 which improvements are and may be executed, but these principles and facts are only useful in the 
 hands of a scientific and experienced metallurgist. 
 
 The manufacture of metals. — In this part of our labors we shall omit the allusion to iron, because a 
 valuable contribution is furnished under the proper head ; we shall further limit ourselves to those 
 metals which are actually manufactured, or are likely to be manufactured in the United States. 
 
 Gold. — Germ, gold; Fr. Or; Lat. Aurum. Gold is found almost over the whole globe, but in most 
 cases in small quantities compared with other metals. At the present time California affords the 
 largest amount of this metal in the world. Virginia, North Carolina, South Carolina, Georgia, and Ala- 
 bama, in the United States, afford gold in considerable quantity. The production of California amounted 
 in the year 1850 to about §40,000,000 worth of this metal ; the other States of the Union together about 
 §2,000,000. Next to the United States, the largest amount of gold is furnished by Russia, from the 
 Ural Mountains. It is found extensively in the South American States, near the Equator, in Africa, 
 Asia, and Europe. Gold is chiefly found in its native condition, in a metallic state, alloyed with silver, 
 and sometimes with tellurium, as is the case in Virginia and North Carolina. In California it is found 
 chiefly in alluvial ground, bedded upon rock in most cases ; it is also found inclosed in quartz rock, ap- 
 parently in veins ramifying the rocks of an extensive mountain range. This California gold is ob- 
 tained chiefly in large grains, and often in lumps of several pounds weight. In the other States of the 
 Union the gold is in very minute fragments, often invisible to the eye if not aided by a lens, only to be 
 detected by crushing and grinding the rock and washing off the debris. This gold is apparently de- 
 rived from the decomposition of iron and copper pyrites, chiefly the first ; which assertion cannot be ob- 
 jected to, because it is founded in principle that almost all iron pyrites contain gold, that the gold ores 
 of that region are rocks which are colored by iron, and that this iron is evidently derived from the de- 
 composition of the pyrites. Pyritous ores of this kind are worked which contain no visible gold, or 
 which do not yield gold at the first crushing and washing, but which furnish gold in a succession of 
 amalgamations, performed after regular intervals of exposure to the air in a fine powder. Gold is also 
 furnished by the silver ores of North Carolina and Virginia. 
 
 A splendid yellow color and brilliant metallic lustre characterizes gold distinctly from other metals ; 
 its specific gravity being 19'3 to water, is another quality easily appreciated by the senses. It is pre- 
 eminently ductile, which qualifies it for an extensive use in the arts. One grain of gold may be drawn 
 into a wire 500 feet long ; silver may be coated with gold, of which the thickness is only the twelve- 
 millionth part of an inch, and still the microscope cannot detect the slightest indication of an interrupt 
 tion of the gold coating. Pure gold requires more heat for melting than either silver or copper, but as 
 all native gold is alloyed with some other metal, it may be considered more fusible than those 
 metals. If, in cupelling gold, the hot globule shines with a greenish light, we may consider the gold 
 not much adulterated ; if it contains 10 per cent., or from there to one-third of silver, the color of the 
 gold is in the hot cupel white as silver. Pure gold is not very volatile, and may be exposed to a strong 
 beat for a long time without loss of metal ; but if gold is alloyed with volatile metal, such as lead, zinc, 
 tnd antimony, it is liable to be carried off by their vapors. Gold has a considerable cohesion, which 
 
METALLURGY. 
 
 399 
 
 inclines it to crystallization. Its crystal form is an octahedron ; it is often found in fragments of crystals 
 imbedded in quartz, of which fine specimens are found in California, and also in the gold region of the 
 Southern States. In melting gold along with pure borax it assumes a -whitish color, as if adulterated 
 with silver ; in melting it again with saltpetre, or common salt, it recovers its rich yellow color. 
 
 The geological position of gold is in the primitive rock. It is found in granite, disseminated in 
 grains and spangles through the mass of rock. In the United States gold is chiefly found in the 
 stratified transition series ; in California it appears to be disseminated through this rock, imbedded in 
 quartz. Most of the gold, the California gold exclusively, is found in alluvial soil. In the Southern 
 gold region this source is much exhausted, and the gold is here obtained from regular, well-developed 
 veins, running parallel with the general direction of the rock strata, southwest by northeast. The 
 plane of inclination of these veins is also parallel wfith the plane of inclination of the general formation. 
 It appears from this that the gold-bearing veins are of a simultaneous origin with the rock ; at least, 
 they have been introduced when the rock was in a plastic condition. In Virginia and North Carolina 
 the gold-bearing veins are a ferruginous talcose slate, often inclined to mica slate. In North Carolina 
 this slate is found to be very hard in many instances, showing a compact solid mass of rock, apparently 
 the same slate, but having been under the influence of a considerable heat, it is hardened. In Vir- 
 ginia this slate is more soft, the fissures open more readily, and the whole vein shows the appearance 
 of soft slate. This slate is impregnated with small quartz veins, from one-eighth to one-half an inch, 
 and often two inches thick. Where these quartz veins are thin and in great numbers, the ore is always 
 found to be richest in gold. This feature of the ore is well developed throughout Virginia, and at Gold- 
 hill, North Carolina. The vein-stone of the gold-bearing veins is strongly impregnated with oxide of 
 iron, showing evidences that this iron is derived from pyrites, because the oxide appears in dots or 
 flowers, and groups of dots. Many of these veins have been traced to that depth where the pyrites are 
 not oxidized ; here they appear in their perfect crystal form, and are profusely distributed through the 
 slate. The oxidation of these pyrites appears to depend on the penetrability of the rock by atmos- 
 pheric agents; where the slate is soft we find it oxidized to the depth of from 50 to 150 feet; where 
 the slate is hard, as is the case at the Sawyer mine, North Carolina, the oxidation reaches hardly ten 
 or twenty feet deep, and is in many places, such as bluffs, not developed at all. At the latter spots the 
 pyrites are in their original form, untouched by oxygen. Where the pyrites are not oxidized the ex- 
 traction of gold is connected with considerable more expense than it is from soft slate and oxidized 
 pyrites. The crushing of the hard slate is in the first place more expensive ; the sulphur of the pyrites 
 destroys a large portion of quicksilver in amalgamation, and the gold cannot be all extracted ; the 
 largest portion of it remains inclosed by the sulphuret of iron, which can only be liberated by destroy- 
 ing that envelope. 
 
 When we consider the great extension of the Southern gold formation, which is at least 500 miles 
 long ; the breadth of the gold-bearing strata in which the veins are imbedded, and which is from 5 to 
 20 miles wide; further consider the depth of these veins, which may be assumed to be 2000 feet, the 
 body of gold ore in these regions is certainly to be regarded as an important source of national wealth. 
 There is, however, one drawback to the rapid extraction of gold from these deposits — the ores are all, 
 without exception, pyritous in greater depth, and to work these sulphurets to advantage no progress 
 has been made up to this time. Various experiments tending to accomplish this purpose, and affording 
 means of extraction, have been tried, but none of these succeeded so far as to work the poorer class of 
 ores. At Goldhill, N. C., where the ores yield from $1.50 to $3 of gold in 100 pounds or one bushel of 
 ore, the pyritous ores are ground, amalgamated, and a certain portion of gold extracted. The crushed 
 ore, now a fine sand, is exposed to the influence of the atmosphere for one year, after which the process 
 of grinding and amalgamating is repeated, and another portion of gold, almost equal to the first, is ex- 
 tracted. An exposure of another year furnishes another crop of gold, which operation may be repeated 
 four or five times without extracting all the metal from the sand. This way of working is tedious, 
 expensive, and will not answer where the ores yield but 25 cents to the bushel. The process of roast- 
 ing these ores by artificial fire is too expensive, and all processes which require much labor are out of 
 the question. Here is a promising field for American ingenuity and industry. 
 
 The extraction of gold is performed in California, and also in some parts of the Southern States, simply 
 by washing the alluvial soil, removing the sand, clay, and debris of rock ; after these operations the gold, 
 as specifically the heaviest matter, will remain in the vessel in which the washing has been performed. 
 This washing may be done to advantage in a tin pan or a sheet-iron pan. Such a pan is filled with 
 sand containing the gold and immersed in water ; in stirring it gently by hand the clay and light sand 
 flow off, and, after some of the earthy matter is removed, the pan is shaken so as to bring the heavier 
 gold to the bottom of it; the superstratum of sand is now removed, and the gold found in the bottom 
 of the pan. Where water is abundant, a more effective machine than the pan is employed. This 
 machine is called a rocker. It is represented in Fig. 2814. 
 
 This is a machine made of wood, about 6 feet long, 26 inches high, and 16 inches wide in the trough. 
 A is a grating of flat iron bars, set edgeways, leaving an open space of about ^ an inch between each 
 bar. By B a strong current of water is let upon this grating, which flows off at the opposite end of the 
 machine. The machine rests upon two gently curved frames, which admit of a rocking motion upon 
 two planks laid on the ground. This apparatus is set in a rocking motion by a boy. two wooden 
 springs on each side of it limiting that motion, and forcing the rocker back at each vibration. The ma- 
 chine represents in its motion a worn-out cradle, which is used beyond gentle rocking. A laborer 
 supplies the rocker with sand at B, by means of a shovel ; the sand which passes through the grating, 
 and also the gold, falls into the trough C, in which quicksilver is kept in case the gold is fine ; it forms 
 here an amalgam of gold. The light sand from O is swept off by the water which passes through the 
 grating. The cradle is more or less inclined towards the discharge of the charges, according to the 
 kind of material to be washed. These operations are quite effective ; secure, for coarse gold ; the fine 
 and floating gold is lost. 
 
400 
 
 METALLURGY. 
 
 Gold inclosed in rocky matter cannot be washed with success in the foregoing described manner ; the 
 rock must be crushed, and is, in this operation, transformed into more or less fine sand. The bulk of this 
 sand is removed by washing, and the rest, with the gold, reserved for amalgamation. The crushing is 
 performed in the stamp-mill, Fig. 2808 ; the sand, including gold, conducted over hides, which retain the 
 gold, and the sand is floated away. The gold and sand from the hides are removed, when the latter are 
 filled, to an amalgamating machine, which combines the gold with quicksilver, and admits the sand to 
 flow off. Instead of hides, woollen blankets are also used for gathering the gold, and there is a diversity 
 of opinions as to the merits of either. Blankets, it is contended, are more expensive than hides, but 
 they have the advantage of working more uniform. Hides are cheaper, but they lose their hairs or 
 wool very soon, and are then not fit to do good work. Hides of short, curly wool are selected ; these 
 are spread on the ground, and over these the water, sand, and gold are led in a broad sheet. In other 
 instances shaking-tables are suspended at the discharge of the stampers, which gather the gold and 
 some sand. Shaking-tables are wooden platforms of 8 or 10 feet long, and from 3 to 4 feet wide, made 
 of 2-inch plank well joined together, and the whole smoothly planed. Around the edges of the table 
 are projecting ribs, which prevent the water from flowing over the edges. In suspending this table, a 
 little inclined to the horizontal, leading the sand and water over it in a broad sheet, and applying a 
 gentle shaking motion to it, the gold will sink to the bottom and move gently down the plane ; it is 
 arrested at the lowest end of the table by a projection on the table. In either of the above cases the 
 gold is brought to the amalgamating machine for amalgamation. 
 
 Most of the gold-mining establishments are provided with Chilian mills for crushing the ore. "We 
 furnish a description of it in its simplest form in Fig. 2808, in which form most of these machines are 
 erected. Still, there are some machines of this kind in North Carolina, which work by four or five run- 
 ners or crushers in one trough. 
 
 2815. 
 
 In Fig. 2815 is such a machine represented as it is in operation at Goldhill. It i9 a cast-iron circular 
 trough of about 16 feet diameter, 10 inches wide, and 6 inches deep; the trough is firmly fixed upon 
 the floor of the mill. In this trough five travellers or head-stones are moving, of 3 feet diameter and 
 6 inches thick, rounded on the edge, made of cast-iron. These travellers are fixed to the revolving- shaft 
 in the centre, and are moved by it. The circular trough is supplied with coarsely broken ore and a con- 
 stant current of water, which latter washes off all the light impurities, and leaves the gold in the trough. 
 At the close of every day’s work the trough is supplied with some quicksilver, which is worked in it for 
 or hour’s time, in which time it absorbs the gold, and is then removed as amalgam. The water 
 from these mills is generally conducted into other machines, in which some of the fine gold which passes 
 from the first machine is gathered. In most cases a shallow round basin, of about 4 feet diameter, is 
 appended, in which a rake moves around with a vertical axis, gently stirring the sediment which may 
 settle from the passing water. It retains only the heavy particles. In other instances, Sullivan 
 bowls (a small machine which derived its name from the inventor, residing in North Carolina) are 
 appended ; these gather the heavy parts which may escape the previous machines. 
 
 2816. 
 
 A Sullivan bowl is represented in Fig. 2811. A vertical wooden shaft of about 18 inches long and 
 2 inches square carries on the lower part a shallow vessel or bowl B, about 2 inches deep and 18 inches 
 in diameter. This bowl is formed of a wooden bottom and sheet-iron periphery. This bowl receives 
 the water from the other machines at or near its circumference, and discharges at the centre. By the 
 lever A, the machine is set in a rocking motion, caused by a crank connected with the same. This 
 machine gathers a great deal of fine gold, but it is an expensive machine, because they work but little 
 water, and it requires many machines to do the work of a small establishment. 
 
 The gold from the various machines, mixed with some sand and other impurities, is carried to the 
 Chilian mill for amalgamation, in case there is no other machine for doing that work. This is an im- 
 perfect machine for amalgamation, and causes losses in quicksilver and gold. In most cases separate 
 
METALLURGY. 
 
 401 
 
 machines are used for amalgamation ; in North Carolina the cradle is generally employed. The cradle 
 is made from the trunk of a tree, hollowed out so as to form a round trough, closed at one end and open 
 at the other, as represented in Fig. 2810. 
 
 Here is a battery of 5 cradles represented : as many as that are frequently connected and moved by a 
 little boy. A cradle is from 1 0 to 1 2 feet long, hollowed out of a trunk of at least 24 inches diameter. The 
 bottom part is thicker than the sides. The first cradle in the drawing shows a section. We see here three 
 or more grooves carved in the bottom ; in each of these grooves from 3 to 4 pounds of quicksilver are put. 
 At the farthest end sand is shovelled in and water led upon it, the cradles being a little inclined towards 
 the discharge. A gentle current of water will have a tendency to wash sand and every thing else down 
 the trough, the trough being, in the mean time, in a rocking motion, which assists the water in washing 
 off every thing. The quicksilver in the grooves is also in constant motion, by which the heavy gran- 
 ules of gold gliding down on the bottom are arrested by it, while the lighter matters, as sand, &c., are 
 not attracted, and pass over the mercury. These machines are very effective, but work slow, and 
 lose much of the fine suspended gold. Other amalgamating machines have recently been put in opera- 
 tion ; their efficacy is, however, not settled, and we hesitate to describe them In North Carolina the 
 German barrel amalgamation lias been introduced within a few months, but we are not informed of the 
 results. In Virginia, amalgamating machines of novel patterns have been tried, but we are not ac- 
 quainted with their effects. 
 
 All amalgamating machines suffer under a common evil, — they cannot work all the water as it issues 
 from the crushing machines to advantage. In all instances half the golden contents of the ore are lost. 
 This is owing partly to the clayish condition of the ore, which clay incloses particles of gold and carries 
 it off, and partly to the extreme division of the gold in the ores of these regions, particularly in North 
 Carolina. This minute division causes the gold to be suspended in water, and in that condition it is 
 carried away by the current. A good amalgamating apparatus, which will work the water directly 
 from the crushing machines, rub off clay and other matter from file particles of gold, so as to make it 
 adhere to the quicksilver, and which does not lose any quicksilver, is still a desideratum in the Southern 
 gold-mining districts. 
 
 Gold, gathered by quicksilver, forms a white amalgam. In the amalgamating machines a surplus of 
 quicksilver is used to secure the fluidity of the mercury ; for if it gets slimy, or still worse, plastic, like 
 clay, it will not absorb any more gold with facility. The fluid amalgam is pressed through a soft 
 leather or a piece of close canvas, to remove the superfluous mercury ; after which a solid amalgam, 
 called quick, remains in the bag. The quicksilver which passes through the bag retains always some 
 gold in solution, the quantity of which varies according to the stuff through which it has been squeezed. 
 The amalgam thus obtained contains from 30 to 7 0 per cent, of gold, according to the mode of working 
 and the quality of the ore. The quick from the Chilian mills generally contains but from 30 to 40 per 
 cent, of gold, while that from stampers contains seldom less than 40, and in most cases from 50 to 60 
 per cent, of gold. This circumstance appears to speak in favor of the stamps ; the difference in the 
 contents of gold, in the amalgam, is owing to its division ; the finer the gold the less of it the amalgam 
 contains. The dry amalgam is distilled in an iron retort, lined with clay ; a red heat will drive off 
 tlie mercury, which is condensed by leading it into cold water. The gold remains in the retort in the 
 form of a powder, which is collected, melted in a crucible along with some saltpetre, and cast into iron 
 moulds, forming square bars of about one pound weight each. One pennyweight of gold of the Virginia 
 mines is generally worth from 90 to 92 cents. North Carolina gold contains more silver than the first, 
 and a pennyweight is seldom more than 90, and in the majority of cases, from 80 to 90 cents to the 
 pennyweight. California gold ranges from 75 to 90 cents. 
 
 In Virginia and North Carolina gold ores are mined, crushed, and amalgamated, which yield but the 
 150,000th part of gold to the bulk of ore, and these ores are worked with profit. The Russel Mining Co., 
 in North Carolina, which operates 12 or more Chilian mills, works ore which yields 10 cents of gold to 
 the bushel, or 100 pounds of ore, with profit. The Louisa Mining Co., which employs stampers for 
 crushing, shows that ores which yield 7 cents in the bushel may be worked, and pay expenses and 
 profit. There are inexhaustible stores of gold ores in the Southern States ; it requires nothing but in- 
 dustry to make its production profitable. 
 
 Silver. — Argent, Fr. ; silber, Germ.; argentum, Lat. Native silver is frequently found ; it appears 
 crystallized, but chiefly in irregular concretions, often in the form of fine hairs. Generally it is com- 
 bined, or alloyed, with gold, quicksilver, antimony, arsenic. It appears as sulphuret in connection with 
 the sulphurets of most other metals. 
 
 Pure silver is the brightest of the metals, of a beautiful white color and rich lustre. Its specific 
 gravity is 1047. It is a little more fusible than gold, but in practice we find generally the reverse, 
 which is owing to the alloys of the two metals, which have a more softening influence upon gold than 
 upon silver. Silver is exceedingly malleable, but not so much as gold ; it crystallizes very readily 
 when exposed for some time to the influence of heat in a melted state, but not so when alloyed to other 
 metals. This latter quality of silver has been made available in practice, in refining lead for silver. If 
 silver bearing lead is exposed to a melting heat, the silver will not crystallize along with some lead. 
 Lead crystallizes more readily in this case, and these crystals may be removed from the fluid mass by 
 an iron dipper pierced with small holes. The crystals of lead, thus freed from the largest part of their 
 silver, are melted and converted into pigs and sold. After repeated melting and crystallization, the 
 remaining fluid is rich in silver, and is now refined in the common way. 
 
 Silver ores are of great variety : there is antimonial silver, found in Mexico and Europe ; sulphuret 
 of silver, almost everywhere ; also the mixtures of sulphuret of silver, with other metallic sulphurets ; 
 chloride, carbonate, and tellurate of silver are curiosities of little practical value. Most of the silver, 
 and in the United States exclusively, is derived from the sulphuret of lead, from galena. In the Union 
 we have but one establishment which manufactures silver to some extent; it is the Washington Mining 
 Co., in North Carolina. As the production of silver from its ore is generally conducted on the same 
 Vol. II.— 20 
 
402 
 
 METALLURGY. 
 
 principles, and as the operation at the Washington mine may be considered one of the most difficult 
 cases, on account of the composition of its ore, we will describe the operation in this instance. 
 
 The ore at this establishment consists chiefly of brown sulphuret of zinc, which is largely mixed with 
 galena, copper, and iron pyrites ; it contains silver, gold, and other metals. The ore as it comes from 
 the mine is broken into coarse fragments, and roasted in heaps in the open air, in the manner described 
 before. The roasting is performed altogether by wood and wood charcoal. After the first roasting the 
 piles are picked over for such ore which is well roasted, and that which is too much roasted. This is 
 brought to the stampers, crushed into a fine powder, and washed, so as to carry off all the oxidized zinc 
 and quartz. If the ore, after its being crushed, is found to be imperfectly roasted, it is returned to the yard 
 and once more subjected to roasting. That part of the ore which is rejected in the yard is piled and 
 roasted along witli some fresh ore- from the mine. In this way it may happen that some of the ore is 
 exposed to several heats. The roasting operation is not considered to be finished until all the sulphuret 
 of zinc is destroyed ; that is, until the zinc is deprived of its sulphur and converted into oxide of zinc, in 
 which form it may be washed away by the water at the stamping-mill. 
 
 The finely powdered ore consists now chiefly of galena, or, in case the roasting operation is well per- 
 formed, of oxide of lead, oxide of iron, oxide of copper, silver, and other matter. This ore is brought to 
 the smelting-furnace, called a high-furnace, and here smelted along with some fluxes by charcoal. In 
 Fig. 2818 such a furnace is represented ; it is a solid work of masonry, calculated to retain its heat if 
 once thoroughly heated. The fire is urged by cylinder bellows, driven by a steam-engine ; the air to 
 the furnace is supplied at the tuyere m. In consequence of the alternate charges of coal and ore, the 
 basin or hearth g is regularly supplied with metal, which is removed at certain intervals of time, so as 
 to afford room for fresh met|l and cinder. In this manner about one ton of lead is obtained in 12 hours, 
 which is removed and put aside for refining. The composition of the ore, which makes its perfect 
 roasting difficult, renders it necessary to make large additions of iron ore to the posts of ore. The iron 
 oxide, which is reduced in presence of carbon in the furnace, will absorb the sulphur from the other 
 metals in case there is any sulphur left after roasting. This circumstance renders the operation tedious 
 and slow. It cannot be avoided but by perfect roasting, which may be considered practically impossi- 
 ble in this instance. The presence of zinc is what renders the operation tedious and expensive. If the 
 zinc is not removed to a large extent, it will, in smelting the ore, carry off by evaporation much of the 
 other metals, gold and silver not excepted. The sulphurets of zinc and lead are very fusible if in con- 
 tact. In roasting the ore these two sulphurets will invariably melt together, which causes the roasting 
 process to be either very expensive or imperfect. All experience with a similar ore in other parts ot 
 the world are confirmatory as to this operation being expensive. 
 
 The lead from these blast-furnaces is transferred to the refining-furnace. Formerly the English re- 
 fining-furnace was used as it is represented in Fig. 2819, in a longitudinal section. Here is a double, 
 or two furnaces represented, which, as is shown, are reverberatory furnaces. The fireplace a throws 
 the flame over the hearth or cupel into a chimney, which is provided with a sliding door at ff to shut 
 off the draft and prevent the fumes of metal from escaping through the stack. The cupel is formed of 
 several layers of bone-ashes, mixed with wood-ashes ; this mas9 is rammed into an iron hoop when in a 
 moistened condition. The form of this cupel is represented in Fig. 2820 ; from above it is a concave 
 egg-shaped dish, of about 5 inches thick, the largest diameter being 4 feet, the smallest 2 feet. When 
 the furnace and cupel are heated, the lead, previously melted in an iron pot, is cast into it ; and now the 
 Dellows, which are represented in Fig. 2821, are set to work, a gentle current of air is thrown over the 
 not surface. The action of the blast is here twofold : it oxidizes the lead and forms litharge of it, and 
 drives by its force the melted litharge to the opposite side of the blast, or the tap-hole, where it flows 
 out and falls into an iron basin, from whence it is carried back to the smelting-furnace. The level of 
 the lead is in this way gradually reduced if not kept up to a certain height ; this is done by casting in 
 melted lead, which is always ready melted in an iron pot. This process is carried on until a certain 
 quantity of lead has been concentrated so far that a little more than one weight of lead is combined 
 with an equal weight of silver ; this rich lead is taken out and refined in a properly prepared cupel. 
 If sufficient rich lead is ready to make from 500 to 1000 ounces of silver, it is refined in a new cupel, 
 
METALLURGY. 
 
 403 
 
 I and the silver melted into a cake. The operation is carried on as before, with the only difference, that 
 no fresh lead is added. 
 
 J The Washington mine has more recently introduced the German refining-furnace represented in Fig. 
 2822, with what success we are not aware. This furnace is larger than the above English furnace, the 
 cupel being at least 6 feet diameter. The drawing shows a section of the furnace, in which the fire- 
 place y, the tuyeres nn, and the door q, into which the lead is charged, are shown. In Fig. 2823 is a 
 ground plan of the furnace shown. Here is the flue x visible, which leads to the stack, and which serves 
 in the mean time to clear off from the surface of the melted lead some of the scum. The cupel of this 
 furnace is made entirely of wood-ashes, which are the refuse ashes from the soap-works, and in this 
 respect the furnace has an advantage over the English furnace. The floor or hollow surface of it is well 
 pounded by wooden mallets, to make it solid and smooth. About four tons of lead are charged for one 
 heat ; it is carefully laid upon the bottom, and at first gently heated, so as not to injure the fresh bottom 
 
 and dome. When the lead is melted, and all ebullition ceases, the blast is thrown in at the tuyeres n n 
 by setting the bellows at playing on the surface of the melted metal. At first no litharge is made, but 
 a dirty froth of oxydized metals is raked off, to facilitate which formation of froth, fine charcoal dust is 
 thrown on the surface. When all the impurities of the lead are removed in this way, the formation 
 of litharge begins, which flows off at the flue x. The separation of the litharge from the lead must be 
 assisted by a hook, because the blast is generally not strong enough to move the fluid oxide of lead over 
 the large surface of the molten mass. The cupellation of four tons of metal lasts from 18 to 20 hours. 
 Towards the end of the operation some silver is carried off with the litharge, which portion of litharge 
 is therefore carefully preserved, to be remelted by itself or along with other ore. The silver is, in this 
 operation, obtained pure in the first heat ; it is melted into the form of a cake in a cavity prepared for 
 its reception in the centre of the hearth. 
 
 In all these refining operations there is an inevitable loss of metal, disappearing in the form of fumes, 
 through the chimney. This loss is variable, and may be modified by the skill of the workman and 
 the purity of the lead ; it amounts on an average to from 4 to 7 per cent, of the lead melted. 
 
 2822. 
 
 2823. 
 
 The extraction of silver from its ores by amalgamation is not practised in the United States; this 
 process requires rich ores and cheap quicksilver. In the old States of the Union there is no prospect of 
 seeing this process executed; but in California, where rich silver ores and mercury ores abound, there may 
 be a probability of its being executed ; still it is a tedious, expensive operation, which, at the rate of wages 
 paid in the United States, will not yield much profit. Amalgamation is a process not adapted to our 
 social condition; it is too laborious to secure success in ordinary cases of common or average ore. 
 For these reasons we do not furnish a description of this operation. In our condition there is no way of 
 working silver ores profitably but by smelting the ore and refining the lead ; or, in some instances, the 
 new process introduced last year into European establishments may answer our purposes. 
 
 Some of the silver smelt-works of Germany have been in a condition of working poor ores, which, in 
 many instances, have not covered the expenses of smelting or amalgamation, which must be extreme cases, 
 considering German industry and perseverance. A process has been introduced within a short time, 
 which promises to advance the interest of the metallurgy of silver greatly. The operation is as follows . 
 Silver ores which may be poor or contain more or less silver, are coarsely broken or stamped, and then 
 
404 
 
 METALLURGY. 
 
 carried to a reverberatory furnace ; here the ore is heated to redness, calcined, and in that state flora J 
 to 5 per cent, of common salt is added to the ore ; the whole kept in that degree of heat, and stirred bv 
 iron bars for some hours. The object of this operation is to transform the silver contained in the ora 
 into chloride of silver, which is so much more easy, as silver has a predominating affinity for chlorine. 
 If the operation of heating is perfected, the red-hot ore is drawn from the furnace and thrown hot into 
 a boiling concentrated solution of common salt. The hot salt solution will dissolve the chloride of silver, 
 and it is kept in solution so long as that solution is boiling-hot ; it is therefore necessary to filtrate it in 
 this condition. To the hot and filtrated solution a little muriatic acid is added, and then some coarse 
 pieces of crude copper; which latter precipitates all the silver in a metallic state, in the form of a fine 
 powder ; this is gathered and melted in a crucible ; it is pure silver. This process is, to all appearances, 
 simple, and is in fact so ; but it requires an expert chemist to execute the operation. If there is only 
 copper, iron, and silver present in the ore, the operation is simple ; but if there is gold, lead, or quick- 
 silver in the ore, the case is not so easily managed ; for the gold will not pass with the silver into the 
 solution, and the chlorides of lead and quicksilver, which are soluble in the same manner as chloride of 
 silver, are precipitated by the same means. The application of this process to our Southern ores is 
 difficult, but it may be an extremely useful process in applying it to the argentiferous stamp-work of 
 the Lake Superior copper ores. 
 
 The silver ores of the Southern gold region, such as are smelted at the "Washington mines, yield from 
 200 ounces to 300 ounces of silver in a ton of lead ; the ore itself contains on an average 8 per cent, of 
 lead ; the other matter is zinc, iron, copper, tin, and chiefly sulphur. The silver is worth §1.80 the 
 ounce, because it is alloyed with a large portion of gold, which raises its value to double the value of 
 pure silver. 
 
 Copper . — Germ. Kupfer; Fr. Cuivre; Lat. Cuprum. Copper was known to the ancients long before 
 iron ; most of the metallic instruments of the era preceding ours were made of copper, alloyed with 
 tin and other metals. The ancient nations on the old continent, as well as the inhabitants of America 
 before European invasion, understood the art of hardening copper as well as we now understand 
 hardening steel. This art is now lost, and we doubt its utility if it were recovered. Copper is pro- 
 fusely distributed all over the globe; its ores are found everywhere. Native copper is particularly 
 found in this country and in Russia. The ores of copper are chiefly sulphurets, of which the yellow 
 sulphuret, or copper pyrites, forms nine-tenths of all the ore used in the smelt-works. Besides this 
 ore, there is the gray sulphuret ; there are carbonates, arseniates, phosphates, silicates, oxides of cop- 
 per, and others ; all these ores are of more interest to the mineralogist than to the metallurgist. The 
 bulk of ore, particularly in this country, are the yellow pyrites ; besides which, the native copper forms 
 an important source of metal to the smelter. The whole amount of copper produced in the world an- 
 nually is about 33,000 tons, of which Europe produces 25,000 tons ; the rest is American copper. ■* 
 
 In the United States there are four large copper smelt-works, and some smaller. At Boston, New 
 York, Baltimore, and Pittsburg are smelt-works, working on the English plan; smaller furnaces are in 
 Missouri, Wisconsin, and Michigan. At present most of the smelt-works are stopped for want of ore. 
 If all the furnaces in the Union could be kept in operation, we should produce more copper than we 
 want, and have some for export ; for the smelt-works have a capacity of 18,000 tons. The works along 
 the Atlantic coast depend chiefly upon ores from Cuba ; Pittsburg and Boston are supplied from Lake 
 Superior. All the States along the Atlantic coast furnish copper ores, but there must be causes which 
 prevent a regular supply to the smelt-works. Our ores are not particularly rich, still there are mines 
 in New Jersey, Pennsylvania, Virginia, and all the Southern States, which will pay handsomely if car- 
 ried on properly. There is a deposit of native copper in Virginia which will furnish stamp-work 
 equal to Lake Superior. The chief difficulty in our copper-mining business is, that some of these mines 
 have been carried on by ignorant persons ; in other cases, swindlers have abused the confidence of the 
 community. If copper-mining in either of the Atlantic States is carried on with discrimination, indus- 
 try, and not over-sanguine expectations, there is no doubt as to its being a safe and paying business. 
 Many of our copper mines would be, and could be carried on by farmers, or the owners of the soil, it 
 their knowledge of mining and preparation or concentration of the ore were sufficient to make the opera- 
 tion profitable. In these respects the smelt-works can assist a great deal in developing the resources of 
 the country, if they will furnish such instructions to the owners of the mines as will facilitate their 
 operation; for it must be presumed the smelt- works are more qualified to furnish practical information 
 on that subject than any other person or persons can do. Ores do not come now on consignment, be- 
 cause the owner of the ore does not like to run the risk of a sale which appears to him arbitrary. Our 
 Atlantic smelt-works have to exert themselves in developing the sources of ore, and export copper, or 
 they are to stop operations. Lake Superior promises to furnish 6000 tons of copper this year; this 
 will supply nearly the demand of the Union ; there is, therefore, little or no choice for the Atlantic 
 works, but to smelt for export. Here are means, that is, ore and fuel, to go into competition with Eu- 
 rope : it requires some industry to make these means available. 
 
 The smelting of copper ores in all of our smelt-works is carried on in furnaces resembling the English 
 furnaces at Swansea. The operation of smelting is also similar to the English process, all of which 
 elaborate descriptions are furnished in Ure’s Dictionary of Manufactures and Mines. The operation ot 
 smelting is divided chiefly into preparing, or washing and crushing of the ore, calcining, smelting and 
 refining. The washing of these ores is performed at the mines, and also the crushing or concentration, 
 and does not differ from similar operations performed on other ores. The furnaces used in the various 
 operations at the smelt-works are all of the reverberatory kind, and fired by bituminous coal, or by 
 v T ood. Fig. 2824 shows a calcining-furnace in elevation, Fig. 2825 the same furnace in section, and 
 Fig. 2827 shows the ground-plan of the furnace. A is the fire-place, B is the hearth, C an arch into 
 which the ore is drawn ; E E are stationary hoppers, or feeders, and b bbb four work-doors. The ore 
 in this calcining operation is not fused ; it is heated merely to such a degree of heat as will evaporate 
 sulphur and arsenic, and oxidize the metallic ores. These calcined ores are exposed to a second heat, 
 
METALLURGY. 
 
 405 
 
 Either in the same furnace, or, as in most cases, in a separate or smelting-furnace. Such a furnace is 
 represented in Figs. 2832, 2833, showing the plan and section of it ; here A B is the hearth, 0 the fire- 
 place, L the hopper, and K M a receiving-pot filled with water, in which the copper is granulated. In 
 the second operation, or smelting, some copper is produced along with the matt or slag, which is sep- 
 arated and treated in a peculiar way. The matt, which contains but little copper, is returned to the cal- 
 cined ore, 'and smelted along with it. In this operation fluxes are added in case the ore does not con- 
 tain sufficient flux for smelting. Iron forms the best flux, and for these reasons : copper pyrites, which 
 always contain more or less iron pyrites, are the most profitable ores in the smelting operation. Other 
 fluxes are the metallic oxides of manganese, lead and tin, besides which, lime, fluor-spar, or other fluxes 
 are used. 
 
 The copper obtained in the first smelting operation is impure, and classes not higher than a rich matt 
 er melted ore ; its granules consist of copper, iron, sulphur, &c. This matt or coarse metal is once 
 more calcined in the calcining-furnace, and then subjected to another smelting, by which operation a 
 more refined metal is obtained. The latter product is, however, not yet fine copper ; it is matt, which 
 contains 60 per cent, of copper ; it is granulated and roasted as before, and once more smelted, by 
 which a richer matt is obtained. These alternate operations of roasting and smelting are repeated 
 from seven to eight times before fine copper is obtained. The cause of this delay, or repetition of cal- 
 cining, is found in the great affinity of copper for sulphur and arsenic, which it requires repeated fire 
 and cooling to expel successfully. 
 
 The refining of copper is done in the smelting-furnace, or a refining-furnace kept for the purpose. 
 The melting of the pigs is conducted slowly, so as to calcine the copper, in case any impurities are left 
 in the fine copper. When the copper is melted, its surface is covered by finely broken charcoal, which 
 operation is repeated as the charcoal consumes. This refining process lasts for 20 hours, and longer, 
 for one heat of from 8 to 9 tons, after which time the copper is ladled out by means of iron ladles 
 coated with clay. 
 
 The Germans, and all other European nations, also the new copper smelt-works in Baltimore, 
 smelt their copper ores in furnaces similar to those represented in Figs. 2828 to 2831. The opera- 
 tion is similar to that of smelting lead, silver, or iron ores. In these furnaces, which are about 15 feet 
 high, and 3 feet wide, are two tuyeres C C, and a cinder tap-hole in the line G II. The copper is tapped 
 into the basin i, where it is chilled on the surface and forms rosettes, or it is cast into pigs for refining. 
 The latter process is performed in reverberatory furnaces, similar to those described. 
 
 The native copper occurring at Lake Superior, in Virginia, and elsewhere, contains a large portion of 
 silver, which at present is lost; to extract this silver by liquation is expensive, and injurious to the 
 quality of the metal ; to do it by amalgamation is expensive, and hardly would pay the trouble. There 
 are, however, ores which contain more than one per cent, of silver to the copper, and we may assume 
 the whole body of copper contains the half of one per cent.; this would amount, on the 6000 tons of 
 Lake Superior copper to- be furnished this year, to at least If 60,000 worth of silver, which silver is now 
 entirely lost. We recommend for the extraction of this silver the process alluded to above. 
 
 Copper is one of the most useful metals, particularly in its alloys with tin, zinc, and other metals. 
 The native metal is frequently found to be crystallized in concrete, irregular masses, ramifying the rock 
 in which it is found •, it is also found in grains, disseminated through the rock. It is less fusible than 
 silver, of a specific gravity of 8'94. It is highly tenacious, and its fracture fibrous. 
 
 Lead. — Germ. Blei; Fr. Plomb ; Lat. Plumbum. This metal is, like gold, silver, and copper, known 
 since time immemorial. It is one of the metals the most easily obtained from its ores. The chief ore 
 from which lead is smelted is galena or sulphuret of lead, which contains when pure 86'66 parts of 
 metal, and the remainder sulphur. The United States and Spain are at present the contending parties 
 in the lead market, and there is a prospect of our final supremacy. The amount of lead manufactured 
 throughout the world may be about 100,000 tons annually, of which our Mississippi lead region fur- 
 nished last year 20,000 tons, Spain 31,000 tons, and England 39,000 tons. 
 
 The metallurgy of lead is very simple, particularly in this country, where an abundance of good 
 galena is found, as in Missouri, Iowa, Illinois, Arkansas, Virginia, California, and more or less in all the 
 States of the Union. Very little or no lead is smelted from other ores but galena. In the Northwest- 
 ern States, Illinois, Wisconsin, and Missouri, are the principal lead smelt-works ; the operation as it 
 is conducted in these places is very much the same as in other parts of the Union. 
 
 Lead is smelted in the above-named States in reverberatory furnaces and in blast-furnaces. Tha 
 reverberatory furnaces resemble, those in which copper is smelted, of which Figs. 2832, 2833, si ow a 
 
406 
 
 METALLURGY. 
 
 vertical and horizontal section. About one ton of ore, along with one ton of slag from the previous 
 heats, forms one charge. The whole is thoroughly heated by closed doors and suffocated combustion, 
 so as to produce carbonic oxide gas in the furnace, for reducing as much lead from the slags and ore as 
 possible. When in this way most of the lead is extracted, the doors of the furnace are opened, more 
 heat is given, and the mass, ore and slags, thoroughly melted, with the addition of some pure quick- 
 lime, which is occasionally thrown into the melting mass, and well stirred along with the ore. Most o! 
 the lead is yielded by the ore in this operation, still there is more than 25 per cent, of it lost in the 
 slags ; these are resmelted in a blast-furnace. Reverberatory furnaces are heated by dry wood, and 
 produce in 24 hours from three to four tons of metal. 
 
 282s. 283'). 
 
 2832. 
 
 More general than the foregoing are the blast-furnaces for smelting lead. These are furnaces resem 
 oling a cupola in which iron is smelted, more than any thing else ; they are generally built in a rough 
 manner in appearance, but the inside of the furnace coincides with a cupola ; it is generally from six to 
 eight feet high ; the blast is introduced by the nozzle h to the tuyere y. The lead, in gathering in the 
 bottom f is frequently tapped, so as to have but little metal in the furnace at a time. The cinder, or 
 slag, is kept as high as the tuyere, and if it reaches too high some of it is tapped at a tap-hole in the 
 front of the furnace. One blast-furnace will produce in 24 hours about two tons of lead, for which it 
 consumes 6000 lbs. of galena, 25 bushels of charcoal, and about a quarter of a cord of wood. In this 
 operation, as in the reverberatory, a great deal of metal is lost, which in most cases amounts to 20 per 
 cent, or more. The slags contain most of this loss, still a large portion of it is destroyed by evapora- 
 tion. The blast-furnace has the advantage over the reverberatory so far as regards economy, but it 
 does not furnish so much metal in the same time as the latter. 
 
 The slags from the blast-furnace, the reverberatory, and the slags from the old Scotch furnaces, now 
 no longer in use, are gathered, broken into coarse lumps of about two inches, and are then subjected 
 to another smelting in the slag-furnace. The slag-furnace is similar to the above blast-furnace, but it 
 is lower ; its extreme height is only four feet, and in many instances it is only three feet high. The slags 
 are here smelted by charcoal, with the addition of some lime and iron ore, by which about two-thirds 
 of the lead contained in the slags is obtained ; one-third of the metal in the slags, or 10 per cent, of the 
 ore, is therefore irrecoverably lost. These furnaces are the same in principle as that represented in the 
 above drawing ; the work in it differs somewhat from the smelting of ore. The lead and slags flow 
 here continually, the first into a basin nearest the tap-hole in which it gathers ; the latter flows from 
 this basin into a somewhat distant reservoir of water, where it is cooled and thrown away. A slag- 
 furnace will smelt in 24 hours about two tons of metal; this, however, depends upon the richness of 
 the slags ; it will make more if the slags are rich, and will make less if poor. 
 
 The conditions of the lead business are not very encouraging at present ; the profits are so small that 
 the smelting of lead is reduced to an occupation which hardly pays the trouble of carrying it on. If an 
 Illinois smelter, who carries on one furnace, can make ten dollars a day, he does very well. When we 
 consider the risk of bad debts, accidents, and stoppages for want of ore or hands, we find that the 
 smelting of lead pays worse than any other trade. 
 
 Zinc . — This metal was known to the ancients, who melted oxide of zinc, called galmei by the Ger- 
 mans, together with copper, and formed brass of it. A similar process is performed with the red oxide 
 of zinc in New Jersey. The Chinese have known this process longer than historical reports reach. The 
 most abundant ores of zinc are the sulpliurets, blende ; these are found in Virginia and North Carolina 
 
METALLURGY. 
 
 407 
 
 m inexhaustible quantities, along with galena, silver, and the sulphurets of iron and copper. Anothej 
 ore is the oxide of zinc, calamine, which is combined with carbonic acid, or silex, or both of these mat- 
 ters. Large deposits of this kind of ore are found in New Jersey, Pennsylvania, and some of it along 
 the northwestern lakes. 
 
 Zinc is a brittle metal, of a bluish white color and considerable lustre ; it is soon tarnished with an 
 insoluble coating of protoxide of zinc. Its fracture is crystalline and short, and its malleability not 
 remarkable. American zinc, manufactured by the New Jersey Company, is remarkable for its tenacity. 
 Fine wires may be drawn of it, which possess great strength, a beautiful silvery lustre, and fine ap- 
 pearance. The specific gravity of zinc is 6'9 to 7'3 ; it melts at about 700°, and soon burns with a 
 bluish-white light, forming bright white flowers of zinc, a flocculent matter resembling cotton-wool, or 
 snow-flakes — it is oxide of zinc. 
 
 In the United States not much zinc is manufactured in its metallic state at present ; the low price 
 of the European zinc will not admit of working our own ores. Some zinc is manufactured in New 
 Jersey, but the quantity is small in comparison to that imported. Considerable use, however, is made 
 of the red oxide for the manufacture of brass. An important business could be done in the Southern 
 States by working the silver blende for zinc, and extracting the silver in the mean time, either before or 
 after the zinc is manufactured from it. The Silesian process of working zinc ore is the best adapted for 
 working this kind of ore, for which reason we shall describe this operation in preference to other pro- 
 cesses. 
 
 The ore, in this operation, is roasted in a reverberatory furnace, similar to that in which copper ores 
 are roasted, and which have been represented before. After the ore is well roasted, which operation is 
 tedious on sulphurets, it is mixed with an equal volume of culm, that is, bituminous coal-slack, and 
 some small charcoal, in case the ore is fine, to make the mixture porous. The roasted ore, well mixed 
 with its ingredients, is now introduced in lots of 50 pounds of ore into a muffle, which is carefully made 
 of good fire-clay, such clay as fire-bricks are made of- — the Mt. Savage, Maryland, and Johnstown, Pa., 
 clay is, for this purpose, the best. Muffles are round pipes ; they must be slowly dried, and are then 
 baked in a particular furnace. They are, when red hot, inserted into the reducing-furnace, which is a 
 reverberatory, shown in section in Fig. 2834, and in plan in Fig. 2835. A range of muffles is laid on tlio 
 
 2835. 
 
 hearth, a , of the furnace, reaching to the fire-bridge, b, their mouth extending to c. The muffles are 
 closed by a clay slab at the mouth, in which there are two openings, one at the bottom for the charge and 
 discharge of the ore, and one at the top for inserting an iron pipe which is to conduct the vapors of the 
 distilled zinc to the condensing vessel. The vapors of zinc are conducted into cold water, in which it 
 condenses and forms grains ; these are afterwards remelted in an iron pot. One reverberatory contains 
 five muffles, and a double furnace ten. To produce one ton of metal, 10, and from that to 12, tons of 
 bituminous coal are consumed, and one muffle will last for making nearly one ton and a half of zinc. 
 
 Zinc is a useful metal, if it can be obtained at reasonable prices ; it is indispensable in the chemical 
 laboratory, and is very useful in architecture for roofing and for ornaments. Its most important appli- 
 cation is, however, in combination with copper, as brass, of which a great variety of shades of the yellow 
 color are produced. 
 
 . Mercury.' — Syn ., quicksilver : Germ., quecksilber ; Lat., hydrargyrum; has been known from early 
 historical times. The most important mines used to be, and are still, in Spain ; besides which, mercury 
 is made in Idria and Western Germany, in Mexico and California. This subject is of more import- 
 ance to the United States, since the acquisition of California, than it was previous to that time; not 
 only in respect to the manufacture of the metal itself, but in its relation to the gold and silver ores. 
 The quicksilver mines of California had been worked before its annexation, but these mines never at- 
 tracted so much attention as they have done since that country became a part of the Union. The principal 
 nines in California are the Guadalupe and the New Almadan mines, which are some miles distant from 
 each other, and not far in the interior of the country. The ore in these places is a beautiful sulphuret, 
 cinnabar, of a bright, fiery-red color, and yields from 60 to 70 per cent, of mercury. The successful 
 operation of these mines, and a reduction of the price of quicksilver in consequence, is an important- 
 object to the silver mines of California, Mexico, and, in fact, to all the silver mines along the Pacific 
 coast. 
 
 Ihe extraction of quicksilver from its ores is a very simple operation; but, as economy is desirable in 
 all operations of this kind, we will describe the most perfect apparatus invented for this kind of work— 
 if is that constructed by Dr. Andrew Ure for a European establishment of this kind. 
 
 2834. 
 
408 
 
 METALLURGY. 
 
 Fig. 2836 shows a section of a furnace parallel with the front elevation represented in Fig. 2837 
 1 a a are iron retorts; the whole furnace contains 9 of them. I is the fireplace, designed either foi 
 coal or wood. The upper retort is protected against the direct contact of the flame by fire-bricks. K K 
 
 2836. 
 
 shows the flues for the escape of the burnt gases. The whole arrangement is shown in Fig. 2838 very 
 distinctly. The two ends of the retort, a, are shut by two iron lids, secured by cross-bars and screw- 
 bolts, luted with clay. The one end of the retort is provided with an iron pipe b, which leads into a long 
 
 2837. 
 
 condenser e, and from thence into the receiver D, e. The hole L is designed for the introduction of an 
 iron wire, in case any disturbance should happen in the pipe A, where dirt from the ore may accumulate 
 and obstruct the passage of the mercury vapors. The pipe, 
 c, is always partly filled with quicksilver, and kept cool by 
 water contained in a trough which surrounds it. 
 
 The retorts are kept in constant ignition, and a charge is 
 worked in three hours’ time, each charge consisting of 5 
 cwts. of ore. The ore is finely broken, and mixed with a 
 portion of quicklime or porous magnetic iron ore, and, if it 
 can be had, with both mixed together. The quantity of 
 lime or iron depends upon the quality of the ore ; pure ore 
 requires more of it than impure ore. The quantity of 
 quicksilver made in one retort per day depends also on the 
 richness of the ore : the California ore ought to produce at 
 least 600 lbs. in 24 hours in one retort, which will be for 9 
 retorts nearly 2 tons and a half per day. The retorts are 
 charged and discharged from behind, so as to leave the con- 
 densing apparatus undisturbed. 
 
 Tin. — Germ., zinn ; Ft., etain ; Lat., stannum. Tin has 
 been known for ages, and was used by the ancients long 
 before our era. Tin ore is found chiefly as an oxide of tin : 
 it is, in fact, the only available ore. England, Germany, and the East Indies, furnish almost all the 
 tin in market — some is brought from South America, but it is of an inferior quality. In the United 
 States tin ore is found in Connecticut, and there is said to be a good deposit in Missouri ; a small quan- 
 tity is found in the silver ores of the Southern States. Tin is a beautiful metal, and, next to silver, the 
 whitest of all the metals. Its specific gravity is 7'29. It is a little harder than lead, and emits a pe- 
 culiar sound, tin-cry, when bent, but the addition of a small quantity of lead diminishes the strength oi 
 that sound. Tin is more fusible than lead ; it melts at 440°. It is very volatile, and burns in open 
 fire, forming oxide of tin, or putty of tin. The most extensive use of tin is in the manufacture of tin 
 plate, for which purpose a very pure tin is required ; it is further employed for making pewter, bronze, 
 bell-metal, &c., for which purpose it is alloyed with other metals, such as lead and copper. 
 
 The metallurgy of tin is simple, but it requires experience to succeed well ic smelting. The ores are 
 
MICROMETER. 
 
 400 
 
 first concentrated by stamping and washing, which is so much the more easy as tin ores are of a high 
 specific gravity, almost equal to galena. The roasting is invariably performed in a reverberatory fur- 
 nace, which is a tedious operation, and requires from 18 to 20 hours work for one heat; if this operation 
 is not well performed, much trouble and loss is met with in smelting. Tin is the most profitably smelt- 
 ed in a blast-furnace, such as copper or silver ores are smelted in. In England, the reverberatory is 
 employed for smelting some kinds of ore, but the best metal is made in the first furnace. The charges 
 in the blast-furnace consist in charcoal ore, and lime, lead ore or iron ore as fluxes. In the reverbera- 
 tory, the ore is charged along with lime, and culm, or mineral coal slack, as the means of reduction. At 
 the tap-hole of the furnace a receiving basin is moulded, into which the fluid metal is tapped at certain 
 intervals, the fluid slag being conducted to some other reservoir and gathered, to be smelted once 
 more. 
 
 Tin, directly from the smelting furnace, is always impure. It contains all the metals with which the 
 ores are adulterated, and it absorbs, also, metals from the flux. The metal is refined in a reverberatory 
 furnace by eliquation, which process is based upon the ready fusibility of tin. In charging the blocks of 
 tin near the fire-bridge, the hearth being sloped towards the flue, a gentle heat will melt the tin first cf 
 all other metals, and it will flow down the hearth, leaving the other metals in the form of skeletons of 
 the original blocks. The pure metal is removed by tapping it at the flue, and then the heat increased 
 and the other metals melted down : these are kept separate. The tin thus obtained is once more sub- 
 jected to refining, for which purpose it is melted in an iron kettle, and stirred with sticks of green wood. 
 The steam emitted from that wood oxidizes all other metals, and purifies the tin from them ; the former 
 form a light scum on its surface, which is removed, and the metal cast in blocks ; it is now ready for 
 the market. The whole amount of tin manufactured in the world may be estimated at about 10,000 
 tons, of which England furnishes the one half. 
 
 MICROMETER. An instrument applied to telescopes and microscopes for measuring very small 
 distances, or the diameters of objects which subtend very small angles. A great number of contrivances 
 of various kinds, and depending on different principles, have been employed for this purpose ; but it 
 will be sufficient to give a general description of some of the most useful or remarkable ones. 
 
 Wire micrometer. — This instrument, when placed in the tube of a telescope, at the focus of the object 
 glass, presents the appearance represented in Fig. 2839. A a is a spider’s web line, or very fine wire 
 fixed to the diaphragm ; and B b and C c are similar wires stretched across two forks, each connected 
 with a milled-headed screw. By means of these screws the two wires, B b and 
 C c, which are exactly parallel to each other, are movable in the direction per- 
 pendicular to A a- and in order that the wire A a may be placed in any direc- 
 tion relatively to the meridian, there is an adjusting screw, which works into an 
 interior toothed wheel, and turns the apparatus round in its own plane perpen- 
 dicular to the axis of the telescope. 
 
 The method of using the micrometer is as follows: Suppose the object to be 
 accomplished were the measurement of the angle of position and distance of two 
 very close stars ; the telescope being set and kept on the objects, the microme- 
 ter is turned by its adjusting screw until the spider line A a coincides with the 
 line joining the two stars, or threads them both at the same moment. The 
 milled heads of the screws, which carry the two movable wires, are then turned 
 until B b bisects one of the two stars, and C c bisects the other. The observation is now completed, and 
 it only remains to ascertain the position and distance indicated by the micrometer. For the first of 
 these purposes, the circumference of the micrometer is divided into degrees and minutes, and read by 
 two verniers : this reading gives the position of A a in respect of the horizontal and vertical planes, and 
 consequently the angle of position of the two stars. To find their distance, the head of the screw which 
 carries one of the movable wires, for instance C c, is turned until 0 c coincides with B b ; and the num- 
 ber of revolutions, and parts of a revolution, required to effect the coincidence, gives the distance of the 
 stars when the value of the scale of the micrometer is known ; that is to say, when the number of sec- 
 onds of space which correspond to one revolution of the screw is known. The screws must be made 
 with great accuracy, and their heads are usually divided into 60 equal parts, representing seconds. 
 
 The value of the scale, or of a revolution of the screw, is obtained in the following manner : Set the 
 two wires, B b and 0 c, apart to a certain number of revolutions, and place them in the direction of the 
 meridian. Observe the transits of several stars of known declination over the wires ; then multiply 
 each interval of seconds by 15, and by the cosine of the star’s declination; and, taking the mean, you 
 have the seconds of space which correspond to a known number of revolutions of the screw. 
 
 Circular Micrometer . — This instrument, which differs entirely from the above, was first suggested by 
 Boscovich, in the Leipzic Acts for 1140, and used by Lacaille in observing a comet in 1742 ; but seems 
 afterwards to have fallen into disuse until it was revived by Dr. Olbers about 1798. The principle may 
 be explained as follows : If the field of a telescope be perfectly circular, (which may be effected by 
 means of a diaphragm turned in a lathe,) and if its diameter be determined from observation, the paths 
 of two celestial bodies across the field may be considered as two parallel chords, which are given in 
 terms of a circle of known diameter. The differences of the times at which two stars 
 arrive at the middle of their paths will be their ascensional differences ; and the dis- 
 tance between the chords, which is readily computed from their lengths, gives the 
 difference of the declinations of the two bodies. 
 
 The most approved construction of the annular micrometer is that of the late Fraun- 
 hofer. It consists of a disk of parallel plate glass, Fig. 2840, having in its centre a 
 round hole of about half an inch in diameter, to the edges of which a ring of steel is 
 cemented, and afterwards truly turned in a lathe. The disk being mounted in a brass 
 tube, so that it may be accurately adjusted in the focus of the eye-piece, and applied to 
 a telescope, the steel-ring is alone visible, and appears as if suspended in the atmosphere, whence the in- 
 
 2840. 
 
 2839. 
 
 I c 
 
410 
 
 MICROSCOPE. 
 
 stmment is called the suspended annular micrometer. The advantage of this construction consists in Lh« 
 accuracy with which the moment of ingress or egress is determined, from the body being seen in the 
 field of view before it comes up to the edge of the steel ring. The annular micrometer is conveniently 
 used for comparing the place of a small star or a comet with that of a known star in nearly the same 
 parallel of declination. 
 
 Divided object-glass, or double-image micrometer. — This instrument is formed by dividing the object- 
 glass of a telescope or microscope into two halves, the straight edges being ground smooth, so that they 
 may easily slide by one another. A double image of an object in the field of view is produced by the 
 separation of the segments ; and, by bringing the opposite edges of the two images into contact, a 
 measure of the diameter of the object is obtained in terms of the extent of the separation. From its 
 being used to measure the diameter of the sun, this is usually called the heliometer. Instead of a 
 divided object-glass, Ramsden preferred a divided lens in the eye-tube, which form of the instrument is 
 called the dioptric micrometer. The double-image micrometer was suggested by Roemer, about 1678, 
 but first brought into use by Bouguer, about 1748. 
 
 MICROSCOPE. An optical instrument which enables us to see and examine objects which are too 
 minute to be seen by the naked eye. Microscopes are single or compound, according to the nature 
 of their construction ; a single microscope being one through which, whether it consists of a single 
 lens or a combination of lenses, the object is viewed directly; and a compound microscope one in which 
 two or more lenses are so arranged that an enlarged image of the object formed by one of them is 
 magnified by the second, or by the others, if there are more than two, and seen as if it were the object 
 itself. 
 
 Single microscope. — This instrument is, for the most part, simply a lens or sphere of any transparent 
 substance, which refracts the rays of light issuing from a small body placed in its focus, and gives them 
 such a degree of convergency as is necessary for distinct vision. In order that the rays of light issuing 
 from the several points of a very small body may produce a sensible impression on the retina of the eye, 
 it is necessary that the object be brought very near the eye ; but when this is done, the rays coming 
 from its different points are so divergent as to produce only a confused image. Now, if a convex lens 
 be interposed between the object and the eye, and so placed that its distance from the object is a little 
 less than its focal distance, the diverging rays issuing from the object are refracted by the lens, and 
 enter the eye placed behind it, either parallel, or so nearly parallel as to afford distinct vision. The ob- 
 ject is then seen in the direction of the refracted rays, and at the distance at which it could be distinctly 
 seen by the naked eye, and consequently magnified in the ratio of the distance of distinct vision to the 
 focal distance of the lens. This ratio is called the magnifying power of the lens ; hence, for single mi- 
 croscopes, the magnifying power is equal to the distance at which a small object can be seen distinctly 
 by the naked eye, divided by the focal distance of the lens ; and, as the distance of distinct vision is 
 constant, (at least for the same individual,) the magnifying power is inversely as the focal distance. If 
 we suppose the distance which limits distinct vision, in respect of minute objects, to be 5 inches (which 
 is about the average for good eyes) and the focal distance of the lens to be 1 inch, the object will be 
 magnified 5 times in linear dimensions, and 25 times in superficial. If the focal distance is one-tenth 
 of an inch, the magnifying power will be 50 in linear extent, and 2500 in superficial. 
 
 A single microscope may be obtained very easily by piercing a small circular hole in a slip of metal, 
 and introducing into it a drop of water, which will assume a spherical form on each side of the metal. 
 The substance commonly used for microscopic lenses is plate glass ; but they are sometimes formed of 
 rock crystal, which is better. Flint glass, by reason of its great dispersive power, is unfitted for the 
 pjurpose. The precious stones, as the garnet, ruby, sapphire, and diamond, have been proposed ; but the 
 numerous and skilful attempts of Mr. Yarley and Mr. Pritchard have proved that the advantages aris- 
 ing from the greater refractive power of those substances are more than counterbalanced by their color, 
 reflective power, double refraction, and heterogeneous structure. The crystalline lenses of minnows and 
 other small fishes give a very perfect image of minute objects. 
 
 When the object to be examined is of such magnitude as to subtend an angle of some degrees, the 
 requisite distinctness cannot be given to its whole surface by an ordinary lens, in consequence of the 
 confusion occasioned by the lateral rays ; unless, indeed, the rays are only permitted to enter the lens 
 through a very small aperture, whereby the quantity of light is greatly diminished. In order to 
 remedy this inconvenience, Dr. Wollaston contrived a form of lens, to which he gave the name of 
 periscopic lens. Its construction is as follows : two plano-convex lenses or hemispheres are ground to 
 the same radius, and between their plane surfaces a thin plate of metal, with a circular aperture, is 
 introduced. The aperture which appeared to give the most distinct image was about ^ of the focal 
 length in diameter ; and, when the aperture was well centered, the visible field was as much as 20° 
 in diameter. A lens of this kind possesses the double advantage of having a very short focal dis- 
 tance, and very little spherical aberration. Dr. Wollaston’s contrivance may, however, be improved 
 upon in various ways ; for example, by filling up the central aperture with a cement of the same 
 refractive power as the lenses, whereby the loss of fight from the double number of surfaces is avoided ; 
 or by grinding away the equatorial parts of a sphere of glass, so as to leave a deep groove all round 
 it, in the plane of a great circle perpendicular to the axis of vision, and filling the groove with opaque 
 matter. This last construction is called the Coddington lens, (from the name of its proposer,) and 
 when executed in garnet, and used in homogeneous fight, it is considered by Sir David Brewster 
 to be the most perfect of all lenses, either for single microscopes, or the object lenses of compound 
 ones. 
 
 In using a single lens as a magnifier, it is always necessary that the fight be made to pass through 
 a very small aperture, in order that the object may be seen distinctly and without distortion. This 
 necessity arises, both from the spherical aberration and the chromatic dispersion of the fight falling on 
 the surface of the lens under an angle of considerable obliquity ; and the consequence is, that the 
 quantity of fight admitted to the eye is so much diminished that the object cannot clearly be seen 
 
MICROSCOPE. 
 
 411 
 
 To remedy tills inconvenience, Dr. Wollaston proposed a combination of two lenses, called, in const* 
 quence, a microscopic doublet, the optical partof which may be described as follows: M and N, Fig. 
 2841, are two plano-convex lenses, whose focal lengths are in the ratio of 8 to 1, or nearly so, and 
 placed one over the other so that their plane sides are towards the object. The adjustment of the 
 distance between the lenses is best accomplished by trial ; and they must, accordingly, be so mounted 
 that the distance may be varied at pleasure. A D is a diaphragm or stop for limiting the aperture. 
 Though it does not appear that the stop was contemplated by Dr. Wollaston, who makes no allusion 
 to it, the performance of the microscope depends much on its nice adjustment. It is obvious that as 
 each of the pencils of light from the extremities of the object is rendered eccentric by the stop, and 
 made to pass through the two lenses on opposite sides of the common axis, they are affected by oppo- 
 site errors, which, in some degree, serve to counteract each other. This doublet, when correctly made, 
 is infinitely superior to any single lens, and will transmit a pencil of from 35° to 50° wdthout any very 
 sensible errors. The original description by Dr. Wollaston is given in the Philosophical Transactions 
 for 1829. 
 
 The above construction has been improved upon by substituting two plano-convex lenses for N in 
 the doublet, the plane side of the one being in contact with the convex side of the other, and the stop 
 being retained between them and the third. This combination is called a triplet ; and its advantage 
 is, that the errors of the doublet are still further reduced by the greater approximation to the object, 
 in consequence of which the refractions take place nearer the axis. 
 
 When the magnifying power of the lens is considerable, and, consequently, its focal distance very 
 email, it requires to be placed at the proper distance from the object with great precision ; and, as it 
 cannot be held in the hand with sufficient steadiness for any length of time, it requires to be mounted 
 in a frame having a rack and screw, by means of which its distance from the object can be adjusted 
 with accuracy. Mirrors for collecting the light and throwing it upon the object are also necessary for 
 many purposes. 
 
 Compound microscope. — The simplest kind of compound microscope is formed by the combination of 
 two converging lenses, whose axes are placed in the same straight line. The arrangement of the 
 lenses, and the path of the rays, will be readily understood from the annexed diagram, Fig. 2842. 
 M N is the object-glass, which has a very short focal distance, and P Q the eye-glass. A small object, 
 a b, being placed before the object-glass, a little further from it than the focus or parallel rays, a re- 
 versed and enlarged image, a ' b, will be formed at some distance behind M 1ST. The lens P Q is placed 
 at such a distance from M N that its principal focus is in the line at a 1 b' ; consequently the rays of 
 light from every point of the image a' b' emerge nearly parallel from P Q, and to the eye at E the 
 image a ' b' is magnified, as if it were a real object, into a" b", and appears at a distance equal to the 
 limits of distinct vision, which, as stated above, is about 6 inches. 
 
 The magnifying power of this microscope, or the ratio of a" b" to a 6 is found as follows : In the first 
 place, if we assume d to denote the distance of the first image a' b' from MN, and / the distance of 
 a b from M 1ST, or the focal distance of MN, we have this proportion, a' b' : a b : : d :/. In the second 
 place, if l denote the limit of distinct vision, or distance of the second image a" b" from P Q, and f the 
 focal distance of P Q, (or distance of a' b' from P Q,) we shall also have a" b" : a' b ' : : l :/'. These two 
 
 proportions, being multiplied together, give which, therefore, is the magnifying power of 
 
 a u J f 
 
 the microscope. It thus appears that the magnifying power is inversely as the product of the focal dis- 
 tances of the two lenses, and directly as the distance between them. The magnifying power will there- 
 fore be increased by increasing the distance between the object-glass and eye-glass ; but a limit is 
 soon placed to this increase by the indistinctness of the image, and, in practice, it is not advisable to 
 make the distance of a' b' from M N more than from 5 to 7 inches. Suppose the focal distance of M N to 
 be \ of an inch, and the distance of a' V from M N to be 5 inches, then a' b' will be 20 times greater 
 than a b ; and if the focal distance of PQ be ^ an inch, and the distance of a" b" from P Q be 5 
 inches, then a" b" will be 10 times greater than a' b’, and consequently 200 times greater than a b ; 
 or the magnifying power is 200. 
 
 The great defects of the microscope, when constructed in the manner now described, consist in the 
 smallness of the field of view and want of achromatism in the object-glass, in consequence of which 
 the images a' b' and a" b" are fringed with the prismatic colors. For the sake of enlarging the field 
 of view, a third lens, larger than either of the others, and called the field-glass, is usually interposed 
 between the image a' b' and the object-glass. 
 
 Reflecting microscope. — The principle of the reflecting microscope is very simple, and easily con- 
 
412 
 
 MILLSTONE. 
 
 reived. Suppose M N, Fig. 2843, to be a concave speculum, and a small object to be placed before it 
 at /. A reflected image of the object will be formed at F, where the rays issuing from each point of 
 the object intersect each other, and magnified in the proportion of FM to / M. If the image at F ia 
 viewed with the naked eye, the instrument is a single reflecting microscope ; but if the image is view- 
 ed through a refracting lens P Q, (or a combination of lenses forming an eye-piece,) by which the rays 
 are made to converge towards the eye at E, it becomes a compound reflecting microscope. 
 
 The reflecting microscope was first proposed by Sir Isaac Newton in the form now described ; but, 
 on account of the impracticability of illuminating the object, it was long disused. It has, however 
 been recently revived, under a modified form, by Professor Amici, of Modena, who places the object 
 outside the tube of the microscope, below the line N F ; and, in order that an image may be formed in 
 the speculum, the rays issuing from the object fall upon a small plane mirror placed at / inclined to 
 the axis of the speculum in an angle of 45°, whereby they are thrown upon the speculum in the same 
 manner as if the object itself were placed at/. By this means the object can be illuminated with per- 
 fect facility. The concave speculum MN is ground into an ellipsoidal surface ; the diagonal mirror is 
 placed at the nearest focus/ and the image is consequently formed at the other focus F. The image 
 at F is viewed with a single or double eye-piece, as in other microscopes. 
 
 2843. 2844. 
 
 Solar and oxyliydrogen microscopes. — The solar microscope is composed essentially of a mirror and 
 two converging lenses. The plane metallic mirror C D, Fig. 2844, reflects the sun’s rays upon the lens 
 MN, by which they are concentrated upon the object ab placed in its focus. The object being thus 
 strongly illuminated, is placed before a second lens P Q, (a little before the principal focus,) by which 
 the rays are rendered still more convergent, and produce a magnified image of the object upon a 
 screen suitably placed at a distance of some fee behind the lens. The object is here supposed to be 
 transparent ; if opaque, the light must be thrown upon it in such a manner as to be reflected by it to 
 PQ. The mirror and lens MN are placed in the hole of a window-shutter in a darkened room; and 
 the mirror must be movable, in order that the sun’s rays may always fall upon it under a proper angle 
 to be reflected to the lenses. But the solar microscope is now almost entirely superseded by the 
 oxyliydrogen microscope ; so called because the illumination, instead of being produced by the sun’s 
 rays, is produced by burning a small piece of lime or marble in a stream of oxyliydrogen gas. In this 
 case the plane mirror C D becomes unnecessary ; and instead of the lens M N a concave speculum is 
 employed, in front of which the ball of lime is placed, and an intense light thus thrown upon the ob- 
 ject ab, the rays from which are brought to foci upon the screen by the lens P Q. For full details 
 respecting the management of this apparatus, which forms a very popular exhibition, the reader is 
 referred to Goring and Pritchard' s Micographia. For descriptions of the various kinds of micro- 
 scopes see Brewster's Treatise on JVeiu Philosophical Instruments ; or Ency. Brit., art. “ Microscope.” 
 
 MILE. A long measure, equal to 1160 yards. See Weights and Measures, for miles of different 
 countries. 
 
 MILL. The term is most commonly applied to machines for grinding corn, but it is likewise used in 
 a more loose sense to denote machines intended for other purposes, as the grinding of bark, for felling 
 wood, for preparing flax, cotton, &c. See Water-wheels, Geering, and the various processes of man- 
 ufacture commonly classed under this head. 
 
 MILLSTONE, or Burr-Stone. This interesting form of silica, which occurs in great masses, has a 
 texture essentially cellular, the cells being irregular in number, shape, and size, and are often crossed 
 by thin plates, or coarse fibres of silex. The burr-stone has a straight fracture, but it is not so brittle 
 as flint, though its hardness is nearly the same. It is feebly translucent; its colors are pale and dead, 
 of a whitish, grayish, or yellowish cast, sometimes with a tinge of blue. 
 
 The burr-stones usually occur in beds, which are sometimes continuous, and at others interrupted 
 These beds are placed amid deposits of sand, or argillaceous and ferruginous marls, which penetrate 
 between them, filling their fissures and honeycomb cavities. Burr-stones constitute a very rare geologi- 
 cal formation, being found in abundance only in the mineral basin of Paris, and a few adjoining dis- 
 tricts. Its place of superposition is well ascertained : it forms a part of the lacustrine, or fresh-water 
 formation, which, in the locality alluded to, lies above the fossil-bone gypsum, and the stratum of sand 
 and marine sandstone which covers it. Burr-stone constitutes, therefore, the uppermost solid stratum 
 of the crust of the globe ; for above it there is nothing but alluvial soil, or diluvial gravel, sand, and 
 loam. 
 
 Burr-stones sometimes contain no organic forms, at others they seem as if stuffed full of fresh-water 
 shells, or land shells and vegetables of inland growth. There is no exception known to this arrange- 
 ment ; but the shells have assumed a silicious nature, and their cavities are often bedecked with crys- 
 tals of quartz. The best burr-stones for grinding corn, have about an equal proportion of solid matter 
 and of vacant space. The finest quarry of them is upon the high ground near La Ferte-sous-Jouarre 
 The stones are quarried in the open air, and are cut out in cylinders from one to two yards in diameter, 
 by a series of iron and wooden wedges, gradually but equally inserted. The pieces of burr-stones are 
 afterwards cut in parallelopipeds, called panes, which are bound with iron hoops into large millstones 
 These pieces are exported chiefly to this country and England. Good millstones of a bluish white 
 tolor, with a regular proportion of cells, when six feet and a half in diameter, fetch 1200 francs a-piece, 
 or £48 sterling. A coarse conglomerate sandstone or breccia is, in some coses, used as a substitute for 
 burr-stone, but it is a poor one. 
 
MINERAL KINGDOM. 
 
 413 
 
 MINERAL KINGDOM, materials from, used in the mechanical and ornamental arts. The materials 
 from the mineral kingdom may be divided, so far as regards these pages, into two groups : the earthy, 
 and the metallic. 
 
 The earthy materials, when employed in the mechanical and useful arts, are generally used in their 
 natural states. 
 
 The metallic minerals consist in general of metallic oxides, combined with a larger quantity of some 
 base, such as silex, clay, or sulphur, which are the most common mineralizers ; the cohesion of tire mass 
 has in general to be overcome by heat, which destroys the affinity of the component parts, and allows 
 of the separation of the metals in various ways. Of these processes the author will have scarcely any 
 thing to say, but the metals themselves, when so obtained, will be treated of at some length here- 
 after. 
 
 The earthy and crystalline mineral substances are less frequently worked by the, amateur than the 
 metallic, and therefore they will be noticed rather briefly, and in the order of their hardness, as derived 
 from the folio whig table : 
 
 Table of Hardness, etc. 
 
 1. Talc 
 
 2. Compact Gypsum. 
 
 S. Calcareous spar.... 
 
 4. Fluorspar 
 
 5. Apatite 
 
 6. Felspar 
 
 1 Silex 
 
 8. Topaz 
 
 9. Sapphire 
 
 10. Diamond 
 
 Lead, Steatite or Soapstone, Meerschaum 28 
 
 Tin, Ivory, Potstone, Figure-stone, Cannel-coal, Jet, <fcc 90 
 
 ( Gold, Silver, and Copper, when pure ; soft Brass, Serpentine, Mar- 
 
 '{ files, Oriental Alabaster, &c Il 
 
 Platinum, Gtm-metal 53 
 
 Soft Iron 48 
 
 Soft Steel, Porphyry, Glass 52 
 
 Hardened Steel, Quartz, Flint, Agate, Granite, Sandstone, Sand 20 
 
 Hardest Steel 6 
 
 Ruby and Corundum 1 
 
 Cuts all substances 1 
 
 The above table exhibits the relative degrees of hardness of the several substances in the estimation 
 of the mineralogist ; thus talc may be scratched by gypsum, gypsum may be scratched by calcareou* 
 spar, the last by fluor spar, and so on throughout; in the second column are named some of the miner 
 als, metals, and other substances of similar degrees of hardness, and the last column contains the nura 
 ber of minerals which, in respect to hardness, are ranked under each of the ten grades. 
 
 In the several practices of working these numerous substances, structure must also be taken into ac- 
 count, or the mode in which their separate particles are combined ; thus hardened steel, quartz, granite, 
 and sandstone, are each included under the number 7. The particles of the steel, however, are much 
 more firmly united than those of the glassy crystalline quartz, which is far more brittle ; and still more 
 so than the aggregations of crystals in the granites ; the last may be wrought by sharp-pointed picks, 
 and chisels of hard steel, which crush and detach, rather than cut the crystals ; and although sandstone 
 consists almost entirely of particles of silex cemented with silex, still, as the grains of the sandstone 
 are but loosely held together, it may be turned with considerable facility with the tools used for turn- 
 ing marble, and which is the every-day practice in turning the grindstone. Whereas granite, which 
 contains from half to three-fifths felspar, a substance softer than silex, and porphyry, which consists of 
 crystals of felspar imbedded in a base of felspar, cannot be turned with steel tools at all. 
 
 Several mineral substances are formed by the successive deposition of their component parts in uni- 
 form layers, as in mica and slate ; or in alternate depositions, as in the Yorkshire flags or sandstones. 
 Mica may in consequence be split into leaves even so thin as the one 50,000th of an inch ; it is used by 
 the optician in mounting objects for the microscope, and is often misnamed talc ; slate may be split into 
 very thin leaves of considerable size, and those sandstones which result from the recomposition of 
 granite are most readily split through the layers of minute scales of mica, which, being lighter than 
 the other ingredients, are deposited in separate layers. 
 
 Many hard substances, as the agates, carnelians, and flints, show neither the crystalline nor lamellar 
 structure, and break with a fracture termed the conchoidal, of which the broken flakes of glass, flint, 
 and pitch, may be taken as familiar examples* Hard crystalline gems, on the other hand, are formed 
 of laminae, arranged in various directions, and may be readily split by the hammer and chisel through 
 their natural cleavages or joints ; but in most of the earthy minerals, grinding is resorted to for obtain- 
 ing the ultimate and defined shapes, the consideration of which methods are for the present deferred. 
 Should none of these processes be resorted to by my readers, they will at any rate serve to explain the 
 broad features of the respective influence of the mineral materials (amongst others) upon tools, which 
 is undoubtedly an important link in our subject, and one full of general interest and variety, from the 
 diversity of the methods which are pursued in such of the useful ard ornamental arts as require these 
 natural mineral substances, that include both the softest and hardest solids with which we are ac- 
 quainted. 
 
 The hard mineral substances are mostly attached to the lathe by resinous cements, as driving them 
 into hollow chucks, like pieces of wood or metal, would endanger their being broken, from their crys- 
 talline nature. The soft cements consist of about half a pound of resin, one ounce of wax, and any 
 fine powder, often the fine dust from the stones that are turned ; pounded brickdust and coarse flour 
 
 * Flint, when first raised, may be split with remarkable precision, with the imperfectly flat conchoidal fracture, as may be 
 well observed in gun-flints ; the perfection of the keen edges thus produced, exceeds that of any which may be obtained 
 upon similar substances by art; when the water is completely dried out of the flint it breaks with the ordinary conchoidal 
 tracture. 
 
414 
 
 MINERAL KINGDOM. 
 
 are used, and pitch also enters into the composition of other kinds. Shellac, either alone or mixed 
 with half its weight of finely powdered pumice-stone, is sometimes employed; and fine sealing-wax, 
 which is principally shellac, is used, as well as many other kinds of cement. The stone is in general 
 warmed to the melting point of the cement, but sometimes the latter is melted by friction alone. 
 
 Clay. — This material is only worked in the soft and plastic state. In pottery, it is attached to 
 the potter’s wheel or horizontal lathe, by its own adhesiveness alone, and is turned by the hands and 
 blunt wooden tools ; it is also pressed into moulds of metal and plaster of Paris, some of wliich are 
 mounted on the lathe when the objects are smoothed within and moulded without. Lathes with 
 vibrating mandrels, or possessing the movement of the rose-engine, are likewise employed for the pro- 
 duction of some works in pottery and china. The artists who model in clay, use blunt instruments, 
 mostly of wood, which are rounded at the ends ; and all artisans cut or divide this material with a 
 stretched pack-thread, or a metal wire. The clay for superior pottery works and modelling, often 
 called pipe-clay, is decomposed felspar — it is mostly obtained from Cornwall and Devon ; and the im- 
 portance of the Stourbridge, and some other refractory clays, in the construction of crucibles and fire- 
 bricks for a variety of other purposes in the arts, must not be overlooked. 
 
 Meerschaum — Amber. — These are principally used for smoking-pipes. Previously to being turned, 
 the meerschaum is soaked in water ; it is then worked with ordinary tools, and is described “ to cut 
 like a turnip.” After having been dried in a warm room, it is polished with a few of its own shavings, 
 and rubbed with white wax, which penetrates its surface. Sometimes the pipes are dipped into a 
 vessel containing melted wax. 
 
 Jet, cannel coal, Ac. — Jet is found at Whitby, Scarborough, and Yarmouth, and is also imported 
 from Turkey, but it is not generally met in large pieces. It may be turned with most of the tools 
 for the soft and hard woods, and worked with saws and files, all used in the ordinary way. Jet, until 
 polished, appears of a brown color, and is manufactured by the lapidary into a variety of ornaments, 
 such as necklaces, ear-rings, and crosses. 
 
 Cannel coal is principally obtained in England from Yorkshire, Shropshire, Derbyshire, and Cum- 
 berland. It is also found in parts of Scotland and North Wales. It occurs in seams, generally about 
 three inches, but occasionally one foot thick, amongst ordinary coal ; sometimes, as at the Angel Bank 
 Colliery, near Ludlow, it constitutes the entire bed. Compared with jet it is much more brittle, also 
 heavier, and harder ; it is less brown when worked, less brilliant, but more durable when polished ; 
 neither of them are at all influenced by acids or moisture, although they temporarily expand by heat. 
 
 Cannel coal may be thought to be a dirty and brittle material, but this is only partially true ; it is 
 far better suited to the lathe than might be expected, although a peculiar treatment is called for in 
 the entire management, which commences with the selection of pieces free from flaws, of a compact 
 grain, and of a clean conchoidal rather than flaky structure. 
 
 All the tools for cannel coal are ground with two bevels exactly like the chisel for soft wood turn- 
 ing, but they are held horizontally ; a small gouge, from one-quarter to three-eighths of an inch wide, 
 also slightly bevelled oft' from within, is used for roughing out, or rather bringing the work as near as 
 possible to the shape, to save the finishing tools : these should be ground with thin and very sharp 
 edges, otherwise they burnish instead of scrape the work. The ordinary tools for ivory and hard wood, 
 if employed, must be held downwards at an angle of about twenty degrees. These tools are some- 
 times used with a wire edge turned up in the manner of a joiner’s scraper. 
 
 The plankway surfaces turn the most freely, and with shavings much like those of wood ; the edges 
 yield small chips, and at last a fine dust, but which does not stick to the hands in the manner of com- 
 mon coal. Flat objects, such as inkstands, are worked with the joiner’s ordinary tools and planes; but 
 with these likewise it is also better the edge should be slightly bevelled on the flat side of the iron. 
 The edges of cannel coal are harder and polish better than the flat surfaces. 
 
 Alabaster. — This is a sulphate of lime, or compact gypsum, which occurs in various places ; in 
 England the finest is found near Derby, where the pure white is employed for the purposes of sculp- 
 ture, but the finest white alabaster is from Italy ; the variegated kinds are turned into vases, pillars, 
 and other ornamental works. 
 
 The Italian alabaster, when first raised, is semi-transparent like spermaceti ; it is wrought in this 
 state. The works are generally rendered of a more opaque white by placing them in a vessel upon 
 little fragments of the stone, so that they may be entirely surrounded by the cold water, which is 
 then poured in and very slowly raised to nearly the boiling temperature ; this should occupy two 
 hours. The vessel is then allowed to cool to 10° or 80° Fahr., the object is taken out, closely 
 wrapped in a cloth, and allowed to remain until dry. The alabaster at first appears little altered, 
 but it gradually assumes the opaque white ; for the first six months it is considered to remain softer 
 than at first, but to become ultimately somewhat harder from the treatment. 
 
 Alabaster readily absorbs grease and dirt of any kind, but it is cleaned by the Italians very dexter- 
 ously ; some use weak alkaline and acid solutions. Soap and water are not to be recommended, as 
 the unpolished parts absorb the oil of the soap. 
 
 There are but few kinds of tools employed in turning alabaster, namely, points for roughing out, 
 flat chisels for smoothing, and one or two common firmer chisels, ground convex and concave for curved 
 lines. The point tools used in Derbyshire are square, and described under marble ; the Italians pre- 
 fer a triangular point, as an old triangular file driven into a handle and ground off obtusely at the 
 ?nd. The carved parts are done by hand with small gouges, chisels, and scorpers of various forms and 
 sizes ; drills, files, and saws are also employed, and the surface, unless polished, is finished with fish- 
 skin and Dutch rush. 
 
 The fibrous gypsum, called from its brilliant appearance satinstone, is much softer; it is turned into 
 necklaces and small ornaments by a sharp, flat chisel, held obliquely ; a square point would split off 
 the fibres. All the above kinds of alabaster or gypsum produce, when calcined, the well-known 
 plaster of Paris, a substance used for cementing together such of the vases as are made of detached 
 
MINERAL KINGDOM. 
 
 415 
 
 parts; plaster of Paris also renders other and far more important services in a variety of the usefu 
 and ornamental arts. 
 
 Oriental alabaster is a very different substance from the above ; it is a stalacrnitic carbonate ot 
 lime, compact or fibrous, generally white, but of all colors from white to brown, and sometimes veined 
 with colored zones ; it is of the same hardness as marble, is used for similar purposes, and wrought by 
 the same means. 
 
 Slate. — The common blue and red slates consist of clay and silex in about equal parts ; the largest 
 slate quarries, perhaps in the world, are at Bangor in Wales. The blocks, when quarried, are split 
 into sheets, sometimes exceeding eight feet by four, by means of long, wide, and thin chisels, applied on 
 the edge, parallel with the lamina;, and struck with a mallet or hammer. The sheets are sawn into 
 rectangular pieces and slabs, by ordinary circular saws with teeth, moved rather slowly ; and these 
 are afterwards planed for billiard-tables, <fcc., in machines nearly resembling the engineer’s planing- 
 machiues for metal, but with tools applied at about an angle of thirty degrees with the perpendicular. 
 The process of sawing slate appears rather crushing than cutting, or a trial of strength between the 
 tool and the slate, as the latter is carried up to the saw by machinery, and cannot recede from the in- 
 strument ; the saw is sharpened about four times a day, and is worn out in about two months. The 
 planing tools for common slabs are six inches wide, and when made of the best cast-steel and properly 
 tempered, they last a day and a half without being sharpened ; the jambs for chimney-pieces and 
 other mouldings, not exceeding about six inches wide, are planed with figured tools of the full width. 
 
 Slate is also turned in the lathe with the heel or hook, tools used for iron, and also with ordinary 
 tools, used witli or without the slide rest, which are, however, rapidly blunted when applied superfi- 
 cially ; it is much tougher at the ends or edges of the laminae than at the flat sides. Slate has been 
 recently worked into chimney-pieces, and a variety of objects for internal decoration, which are 
 ornamented by a patent process, in the manner of papier nidche and china; imitations of marbles and 
 granite are thus made at about one-third the prices of marble. Some of the substances known to 
 mineralogists as slates are exceedingly hard, and vary from the hardness 24, to that of flint or 7. 
 Many varieties, including the Turkey oilstones, are used for sharpening tools ; and this family also 
 includes the touchstones formerly used in assaying gold. 
 
 Serpentine, potstone, steatite. — These are natural compounds of magnesia and silica. They are 
 generally worked immediately on being raised, being then much softer ; but with the evaporation of 
 their moisture they assume the general hardness of marble. The serpentine and steatite are found 
 abundantly in Cornwall ; serpentine is often called green marble, and by the Italians Verde de prato. 
 It is much used ; but some of the serpentines will not polish well. 
 
 Potstone is an inferior variety of serpentine ; in Germany it is abundantly turned into various 
 domestic articles in common use, whence its name. 
 
 Steatite is called soapstone, from its smooth, unctuous feel, and when first raised it may be scratched 
 with the finger-nail ; but it becomes nearly as hard as the others. A variety of steatite is carved by 
 the Chinese into images employed as household gods, and is named figure-stone : until lately, it was 
 supposed to be a preparation of rice. Steatite enters into the composition of porcelain. 
 
 Marbles, limestones . — The term marble is applied by the mason to any of the materials that he 
 employs which admit of being polished ; but the mineralogist designates thereby the compact car- 
 bonates of lime variously colored. The principal kinds worked in the ornamental arts, are the white 
 or statuary marble from Italy, a variety of colored marbles, principally from Devonshire and Derby- 
 shire, and the black bituminous marble from Derbyshire, Wales, and various parts of Ireland. 
 
 The marbles are turned with a bar of the best cast-steel, about two feet long and five-eighths of an 
 inch square, drawn down at each end to a taper point, about two inches long, and tempered to a straw- 
 color ; this point is rubbed on two opposite sides on a sandstone, and held to the marble at an angle of 
 twenty or thirty degrees : the tool soon gets dull, and must be again rubbed on the sandstone to 
 sharpen it. Water should drop on the marble, to prevent the tool from becoming heated and losing 
 its temper. The point will keep getting broader by constant grinding, till it forms a kind of chisel an 
 eighth of an inch wide, after which, it will require drawing out again. For cutting in the mouldings a 
 more delicate point is used, and these are the only tools employed ; a flat tool will not turn marble 
 at all. 
 
 Many of the limestones, although chemically like the marbles, are less compact, and therefore do 
 not readily admit of being polished ; of these may be noticed the Bathstone and other oolites, which 
 are aggregations of egg-shaped particles, like the roes of fish ; when first raised, they may be cut very 
 readily with an ordinary toothed saw, and turned with great freedom. The Maltese stone, of which 
 many beautiful turned and carved works were recently sold in London, belongs likewise to this 
 group. It is very compact, and nearly as soft as chalk, from which, in fact, it scarcely differs in any 
 respect, except in its delicate brown cream-color. The natives of the island of Malta display consider- 
 able taste in the objects turned and carved in this limestone. 
 
 Fluor spar is a natural combination of lime and fluoric acid, and the workable variety is peculiar 
 to Derbyshire, where the art of turning it is carried to great perfection. The most costly varieties are 
 the deep blue and purple, found only at Castleton in that county. Fluor being an aggregation of 
 crystals, all having a fourfold cleavage, is very difficult to turn, as the lamina; are easily split ; few 
 even of the best workmen can turn it into very thin hollow articles. The following is the process. 
 
 The stone is first roughed out with a point and mallet, then heated till it will readily frizzle yellow 
 resin which is applied all over it : this penetrates about one-eighth of an inch, and holds the crystals 
 together. It is next rough-turned, and a little hollowed ; it is again heated and resined, and turned 
 still more into form ; then it is bound round with a thin wire, and again resined, and so on until it is 
 sufficiently thin to show the colors. It is then resined for the last time, and polished in the same 
 manner as marble, but the process is more difficult, and ultimately but very little 1 ‘esin remains in the 
 surlace of the work. The only tool used is the steel point. 
 
416 
 
 MINERAL KINGDOM. 
 
 The blue color of fluor is often so intense that the works cannot be wrought thin enough to show it. 
 When this is the case, the stone is very gradually heated in an oven until it becomes nearly red-hot, 
 when the blue changes to an amethystine color. Great care is required, for if suffered to remain too 
 long the color would entirely disappear. The white and lighter kinds of fluor are not worth one-tenth 
 of the value of *he blue, but are wrought in the same manner for commoner works. 
 
 Freestones, sandstones. — Freestone is a term commonly applied by the mason to such of the sand- 
 stones used for building purposes as work freely under the tools ; namely, the stone-saw, a smooth 
 iron blade, fed with sand and water, and the ordinary picks and chisels, which are too familiar to re- 
 quire more than to be named. The freestones are frequently turned into balustrades, pedestals, and 
 vases. The term is used in this country to designate the sandstones used in building. 
 
 Sandstones, from their relatively slight cohesion, may be turned with the point tool used for marble, 
 although, in the workshop, the grindstone is commonly turned with an old file drawn down for some 
 two or three inches to about one-eighth of an inch square, and held downwards upon the rest at the 
 angle of 20 or 30 degrees. It is rolled over and over, which continually produces a new point ; the 
 stone is then smoothed with a flat piece of iron or steel, or rubbed with a broken lump of another 
 grindstone. 
 
 Porphyries, cleans, granites. — The division and preparation of the softest of the former materials, 
 namely, clay, can be accomplished by the hands alone ; in others, as alabaster and slate, with the ordi- 
 nary toothed saws ; and for those of a harder nature, the stone-saw, fed with sand and water, is an 
 economical mode of dividing them with great exactness and little waste, from their original forms 
 to those in which they are ultimately required, and which is greatly facilitated by the structure of 
 such as occur in stratified beds ; but the use of the stoue-saw may be considered to cease with the 
 sandstones. 
 
 Different and far more troublesome methods of working are necessary with those materials now to 
 be considered, that are much harder, and in which the existence of stratification is considered but 
 rarely and imperfectly to exist ; namely, in the compact and cemented porphyries, principally from 
 Egypt and Sweden. The crystalline granites, and some other varieties, appear to merge from the 
 porphyries to the granites, are used for similar purposes, worked by the same means, and ask for an 
 intermediate position. 
 
 In detaching the masses of granitic rock from their natural beds, the points of least resistance are 
 first determined by an experienced eye, and holes are sunk at those points, vertically or inclined, as 
 circumstances may require : the diameters of these holes vary according to the mass and the amount 
 of resistance, and their depths according to the thickness of the blocks to be detached. 
 
 The holes are made with an iron rod, terminating at foot in a chisel-formed edge of hardened steel ; 
 the tool is held by one man, who changes its position at every blow received from sledge-hammers 
 worked by other men who stand around. When the holes are thus made sufficiently deep, they are 
 charged with gunpowder, in order to effect a separation of the mass by blasting ; the ordinary process 
 of tamping confines the powder, and the fuse communicates the blast. The art of the quarryman 
 consists in placing the blast (or shot) where the smallest amount of powder will remove the largest 
 mass of rock with the least breakage, simply dislodging or turning it over ready for converting. 
 
 In converting the rude masses of granite to their intended forms, the line of the proposed division 
 is first marked, and holes from two to three inches deep, and four to six inches asunder, are bored upon 
 this line, by means of an iron rod, terminating at each end in chisel-formed edges of hardened steel, 
 with a bulb in the middle to add weight ; this tool, called a jumper, is made to fall on one spot. It 
 rebounds, and is partially twisted round to present the edge continually in a different angular position. 
 In this manner a very expert workman will bore about a hundred holes a day. Every one of the 
 holes is then filled with two half-round pieces of iron, called feathers, with an iron-pointed wedge 
 between them ; the wedges are progressively and equally driven until the stone splits, and the 
 fissure will be in general moderately flat, even should the mass be four or six feet thick, although in 
 such cases the holes are sometimes continued round the ends also. 
 
 The scouters, the next class of men, employ the jumpers’ feathers and wedges for removing any large 
 projections, by boring holes sideways, and thus casting off large flakes ; the spallers employ heavy axe- 
 formed or mrecMe-hammers, for spalling or scaling off smaller flakes ; and the scablers use heavy pointed 
 picks, and complete the conversion, so far as it is effected at the quarry, ready for the masons employed 
 in erecting the buildings for which the blocks are used, who complete their formation on the spot. All 
 these materials are likewise used in the ornamental arts. 
 
 Porphyry is worked in the lathe with remarkable perfection, and many excellent specimens from 
 Sweden, of vases, slabs, pestles, and mortars, and bearings intended for the gudgeons of heavy 
 machinery, may be seen in London. These objects are first worked as nearly as possible to the re- 
 quired forms with the pick, are then mounted in lathes driven by water-power, and finished by grinding 
 them with other lumps of porphyry, supplied with emery and water; the machinery is kept going day 
 and night, and the gangs of men relieve one another at certain intervals. 
 
 Granite is incapable of being turned in the lathe ; it is therefore treated like porphyry, that is, 
 shaped with heavy picks, and finally with smaller points used with a hammer; it is afterwards ground 
 with circular or reciprocating motion, according to the figure, by means- of iron plates fed with sharp 
 sand, next with emery, progressively finer and finer, upon wooden rubbers, the endways of the grain ; 
 and lastly, the polish is perfected with felt rubbers and crocus. The process is tedious and difficult 
 from the unequal hardness of the particles ; in this respect granite is inferior to porphyry. 
 
 Of late years numerous vases and other circular and ornamental objects have been admirably exe- 
 cuted in polished granites and elvans, which occur of various colors and degrees of hardness ; when 
 decomposed they are friable, and furnish the china stones extensively used as one of the materials for 
 porcelain and china, and also for making very refractory crucibles. 
 
 Agate, jasper, chalcedony, cornelian, <tc., are all composed of silex nearly pure ; they break in general 
 
MINERAL KINGDOM. 
 
 417 
 
 with a conchoidal fracture, and to divide them into plates it is necessary to resort to the lapidary pro- 
 cess'. They may be slit with emery, but it is far more economical to employ diamond powder, as the 
 time then required is only one-third of that called for when emery is used ; these stones are always 
 ground with emery,, and polished with rotten-stone. 
 
 Agate is used as the bearing planes for the knife-edges of delicate balances, for pestles and mortars, 
 burnishers for gilders, and bookbinders, and also for some other purposes in the mechanical arts ; the 
 whole of the stones in this group are largely employed for the purposes of jewelry, the handles ol 
 knives, snuff-boxes, and a variety of ornaments. 
 
 Topaz, sapphire, ruby. — These may be split with plane surfaces through their natural cleavages, and 
 which method is continually employed ; otherwise, they can be only slit with the diamond powder. 
 The first and similar stones may be smoothed with emery, but emery being in hardness only equal to 
 9, produces but little effect upon topaz, upon sapphire and ruby it is almost inert, and on diamond quite 
 so ; the sapphire and ruby, and also diamonds, are therefore always polished with diamond powder. 
 
 On account of the peculiar interest attached to the mechanical applications of the hard gems, it is 
 proposed to depart a little from the subject and order of these pages, to advert to some few of their 
 uses, which may not be generally understood. The sapphire, the ruby, and also the diamond, are com- 
 monly used for the construction of certain parts of the best time-pieces and watches, such as the pivot- 
 holes, pallets, and other parts of the escapements. 
 
 The jewelling consists mostly of two stones : the one, commonly sapphire or ruby, is turned convex 
 above and concave beneath, of two different sweeps, to thin it away at the part where it is to be pierced 
 with the hole, and which is made a little smaller in the middle to lessen the surface bearing. 
 
 The other, which is called the “ top-stone ,” or “ end-stone ,” is generally a ruby, in the form of a plano- 
 convex lens, or else it is a diamond cut into facets ; the flat side of this touches the end of the pivot. 
 
 Each stone is burnished into a brass or steel ring, like some of the lenses of telescopes, and the two 
 stones (separated a slight distance for the retention of oil by capillary attraction) are inlaid in a 
 counter-sunk recess in the side-plate, or other part of the watch, and retained therein by two side- 
 screws, although unimportant variations are made by different artists in the shapes and proportions of 
 the parts. 
 
 The delicacy of these jewelled holes will be imagined, when it is added that in the axis above referred 
 to, the pivot is the one two-hundredth part of an inch diameter. 
 
 The wire for making the pendulum springs for chronometers is sometimes drawn through a pair oi 
 flat rubies with rounded edges ; the stones are cemented into the ends of metal slides having screw 
 adjustments. Sometimes two pairs of rubies are placed one before the other, to constitute a rectangular 
 hole of variable dimensions, for equalizing the wire both in width and thickness. 
 
 Rubies and other gems are drilled with holes conical from both sides, for drawing the slender silver 
 gilt and silver wires used in the manufacture of gold and silver lace ; the wires are afterwards flattened, 
 wound spirally upon silk, and then woven into the lace. Ruby holes are also employed for rounding 
 the leads of ever-pointed pencils ; but for this use they are chamfered from the one side only, and the 
 lead is pushed through from the small side, the ruby is then used as a cutting tool ; ■whereas the hole 
 in the draw-plate is slightly rounded upon the ridge, and acts more as a burnisher or compresser; the 
 action of the wire, which is pulled through in the direction of the arrow, tends to draw the stone more 
 firmly into its seat. The finest holes of all are made by barely allowing the point of the drill to pene- 
 trate into the apex of the conical hole, previously formed on the opposite side of the ruby. 
 
 All these applications are adopted on account of the very great hardness of the stone, but they could 
 scarcely exist were there not one substance still harder than the ruby to serve for the tools by which 
 these several forms are wrought, and the brief consideration of which will now be proceeded with. 
 
 Diamond. — The diamond is the hardest substance in nature, and in common with some other crys- 
 talline bodies, it is harder at the natural angles and edges, and also at the natural coat or skin of the 
 stone than within, or in its general substance. Its peculiar hardness is probably altogether due to its 
 highly crystalline form, as by analysis the diamond, charcoal, and plumbago, are found to be nearly 
 identical ; the first is absolutely pure carbon, the others are nearly so. 
 
 The principal use of the diamond is for jewelry, its preparation for which will be touched upon in 
 the slightest possible manner ; but from its peculiar hardness the diamond fulfils some more really im- 
 portant although less brilliant services as tools, without which several curious and highly valuable 
 processes must be altogether abandoned, and others accomplished in an inferior although more costly 
 manner by other means. 
 
 The diamond is prepared for the purposes of jewelry by three distinct processes, namely, splitting, 
 cutting, and polishing, which will be adverted to in a very few lines. In order to split off the portions 
 not required, the stone is fixed in a ball of cement, about as large as a walnut, the line of division is 
 sawn a little way with a pointed diamond fixed in another ball of cement, and the stone is afterwards 
 split with the blunted edge of a razor struck with a hammer ; the small fragments removed, when they 
 are too small for jewelry, are called diamond bort. 
 
 In cutting diamonds, two stones are operated upon at once ; they are cemented in the ends of two 
 sticks, which are supported on the edges of a box three or four inches wide, rested against two pins 
 as fulcra, and forcibly rubbed against each other ; by which means they abrade each other in nearly flat 
 planes and remove a fine dust called diamond powder, which falls through the fine holes in the bottom 
 of the box, and is there collected. 
 
 The diamonds are lastly polished upon an iron lap or skive, charged with diamond powder, the stone 
 being guided mechanically ; it is fixed by soft solder in a copper cup, or dop, attached by a stout copper 
 wire to the end of the pincers, a flat board terminating at the other extremity in two feet, which rest 
 upon a fixed support, the whole forming a long and very shallow triangular stool, loaded at the end 
 near the stone. In the last two processes the stone is readjusted for producing every separate facet. 
 M e will now proceed to the applications of the diamond as tools. 
 
 Vol. II. — 27 
 
418 
 
 MINERAL KINGDOM. 
 
 The invaluable instrument, the glazier’s diamond, although employed for a consideral le period, was 
 for the first time investigated scientifically by Dr. Wollaston, in 1816, who pronounced its operation tc 
 depend upon a peculiarity of crystallization in the diamond, the facets of which are frequently round 
 instead of flat, and therefore the edges are circular instead of straight. The rounded edge first indents 
 the glass, and then slightly separates its particles, forming- a shallow fissure, with a splitting rather 
 than a cutting action, none of the material being removed. 
 
 The primitive form of the diaitiond is that of a regular octahedron; it is like two square pyramids 
 joined base to base ; the four sides of the pyramids meet at the angle of 90°, their bases at the angle of 
 109° or thereabouts. Many of the diamonds merge from the form of the octahedron into that of the 
 sphere, or a very long egg, in which cases although a disposition to the development of the six points, 
 each formed by the meeting of four surfaces, exists, they are curiously twisted and contorted. The 
 Count de Bournon has published upwards of one hundred forms of crystallization of the diamond, but 
 the irregular octahedrons with round facets are those proper for glaziers’ diamonds. 
 
 The extreme point of any diamond may be employed to scratch glass with a broad white streak, and 
 detach its particles in a powder, hut such glass will break with difficulty, (if at all,) through such a 
 scratch ; whereas the almost invisible fissure, made when the rounded edge is slid over the glass with 
 but slight pressure and almost without causing any sound, is that which produces the effective cut; and 
 the cut or split thus commenced will be readily extended through the entire thickness of the glass, 
 when the extremities of the sheet are bent with the fingers or appropriate nippers. 
 
 If we could obtain a diamond in the form of a circular button, the edges of which were turned to the 
 angle of 90 or 100 degrees, it would be the perfection of the instrument, as there would be then no 
 point to interfere with its action, and any part of its edge might be used. But as the natural diamond, 
 unaltered by the artisan, is always employed, it must be so applied upon the glass, that one of its curved 
 edges bears upon the intended line of division of the glass, and with the extreme point just out of con- 
 tact : this, in so small an object, necessarily confines the position within very narrow limits. 
 
 The patent swivel diamond insures the one condition, by placing the edge of the stone upon the line 
 of the cut, and a few trials at different elevations, generally from 70 to 80 degrees, will soon give the 
 other position. At the commencement a slight force is applied, until the stone appears to bite or hang 
 to the glass, it is then drawn steadily along, with but little pressure, and the good cut will be scarcely 
 either seen or heard. 
 
 To show that the diamond possesses nothing in itself that should adapt it to cutting glass, beyond its 
 peculiar form and hardness, Dr. Wollaston succeeded with great labor in giving the same form to the 
 ruby, the spinel ruby, topaz, and rock crystal, with all of which likewise he effected the cutting of glass, 
 but they were of course far less economical than the natural angle of the diamond itself, which requires 
 no such tedious preparation, and lasts very much longer. 
 
 It must not be supposed, however, the diamond endures forever ; the ordinary painter and glazier 
 may use one diamond throughout his lifetime, by having it reset to expose other angles ; but in some 
 glass-works, where enormous quantities of this useful material are cut up, the consumption of diamonds 
 amounts to one and two dozen or upwards every week, as the sides from being convex, become rapidly 
 concave, and the principle is lost. 
 
 The following figures represent, say two or three times magnified, the forms of diamonds that would 
 be most proper for various tools ; but it will be remembered they are only selected as near to the 
 respective shapes as they can be found, either amongst imperfect diamonds, or from fragments split off 
 good stones in the first stage of their manufacture for jewelry; these pieces are known as diamond 
 bort. The diamonds are mostly fixed in brass wires, by first drilling a shallow hole for the insertion of 
 the stone, which is imbedded slightly below its largest part, and the metal is pinched around it. Shel- 
 lac is also used for cementing them in, and spelter or tin solders may be fused around them with the 
 blow-pipe, but pinching them in annealed brass is preferred. 
 
 2845. 
 
 a b c d e f g h i k l 
 
 When diamond tools Larger than those made of crystals or thin splinters are required, diamond 
 powder is applied upon metal plates and tools of various forms, which serve as vehicles, and into which 
 the particles of diamond powder are imbedded, either by slight blows of the hammer, or by simple 
 pressure. 
 
 In the construction of the jewelled holes, and in similar works, the rubies and sapphires, although 
 sometimes split, are more commonly slit with a plate of iron three or four inches diameter, mounted on 
 a lathe, and charged on the edge with diamond powder and oil. When sliced they are ground parallel 
 one at a time on a flat plate of copper, (generally a penny-piece,) mounted on the lathe, and into the 
 turned face of which small fragments of diamond have been hammered ; this is called a roughing-milL 
 A similar plate with finely washed diamond powder is used for polishing them. 
 
 The rubies are afterwards cemented with shellac, on the end of a small brass chuck, turned cylin- 
 drical on their edges, and bevelled for burnishing into the metal rings. They are also turned concave 
 and convex on their respective faces, the turning tool being a fragment or splinter of diamond, fixed in 
 a brass wire. Fig. a represents the flat view, and Fig. 6 the edge view of such a tool, but of the 
 
MINES, ENGINES FOR. 
 
 419 
 
 form more usually selected for turning hardened steel, namely, an egg-shaped diamond split in two* 
 the circular end being used with the flat surface upwards ; the watch jeweller uses any splinter having 
 an angular corner. 
 
 The convex surfaces of the rubies are polished with conceive grinders of the same sweeps ; the first of 
 copper, the next glass, and the last pewter, with three sizes of diamond powder, which is obtained prin- 
 cipally from Holland, from the men who cut diamonds for jewelry, an art which is more extensively 
 followed in that country than elsewhere. The watch jewellers wash this powder in oil, after the same 
 manner that -will be hereafter explained in regard to emery. 
 
 In drilling the rubies they are chucked by their edges, and a splinter of diamond, also mounted in a 
 wire, is used. Should the drill be too conical, the back part is turned away with a diamond tool to re- 
 duce it to the shape of Fig. c, and from the crystalline nature of the stone, some facets or angles 
 always exist to cause the drill to cut. The holes in the rubies are commonly drilled out at two pro- 
 cesses, or from each side, and are afterwards polished with a conical steel wire fed with diamond 
 powder.. 
 
 In producing either very small or very deep holes, a fine steel wire, Fig. d, is used, with diamond 
 powder applied upon the end of the same, the limit of fineness being the diameter to which the steel 
 wire can be reduced. 
 
 In drilling larger holes in china and glass, triangular fragments of diamond are fixed in the cleft ex- 
 tremity of a steel wire, as in Figs, e and /, either with or without shellac. Another common prac- 
 tice of the glass and china menders, is to select a tolerably square stone, and mount it as in Fig. g 
 in the end of a taper tin tube, which wears away against the side of the hole so as to become very 
 thin, and by the pressure to embrace the stone by the portions intermediate between its angles. 
 
 The stone is, from time to time, released by the wearing away of the metal, but these workmen are 
 dexterous in remounting it; and that the process is neither difficult nor tedious to those accustomed to 
 it, is proved by the trifling sum charged for repairing articles, even when many of the so-called rivets 
 or rather staples are cemented in ; they employ the upright drill with a cross staff. 
 
 A similar diamond drill mounted in brass was used by Mr. Ellis, with the ordinary drill-bow and 
 breast-plate for drilling out the hardened steel nipple of a gun, which had been broken short off in the 
 barrel ; no material difficulty was experienced, although the stone appeared to be so slenderly held. 
 
 For larger holes, metal tubes such as Fig. h, fed with diamond powder, are used ; they grind out 
 an annular recess, and remove a solid core ; copper and other tools fed with emery or sand may be thus 
 used for glass, marble, and various other substances. The same mode lias been adopted for cutting out 
 stone water-pipes from within one another by the aid of steam machinery. 
 
 Fig. i represents the conical diamond used by engravers for the purpose of etching, either by 
 hand or with the various machines for ruling etching grounds ; for ruling medals and other works. 
 Conical diamonds are turned in a lathe by a fragment of another diamond, the outside skin or an angle 
 being used, but’ the tool suffers almost as much abrasion as the conical point, from their nearly equal 
 hardness ; therefore the process is expensive, although when properly managed entirely successful. 
 
 To conclude the notice of the diamond tools, Figs, k and L show the side and end views of a 
 splinter suitable for cutting fine lines and divisions upon mathematical instruments. The similitude 
 between this and the glazier’s diamond will be remarked, but in the present case the splinter is selected 
 with a fine acute edge, as the natural angle would be too obtuse for the purpose. 
 
 Mr. Ross, with a diamond point of this kind, was enabled to graduate ten circles upon platinum, 
 each degree subdivided into four parts ; at the end of which time the diamond, although apparently 
 none the worse, was accidentally broken. A steel point would have suffered in the graduation of only 
 one-third of a single circle upon platinum, so as to have called for additional pressure with the progress 
 of the work, which in so delicate an operation is of course highly objectionable. 
 
 MINES, ENGINES FOR. The locality of a mine will determine the manner in which it ought to 
 be drained. Where the mine is situated on the top or side of a hill, a shaft is led from the bottom ol 
 the mine to the nearest valley, and the water runs off in this way without the application of pumps 
 wrought by steam-engines. Where the mine is situated in a level country pumping becomes neces- 
 sary; and should the mine be deep, say from 100 to 150 fathoms, very powerful steam-engines are 
 required. Where the pumping requires great power, suppose of 200 horses, it is better to construct 
 two small engines than one large one. Where a single engine is used one set of pumps are wrought, 
 and the ascending motion of the piston is employed to raise a weight equal to half the pressure of the 
 water in the pumps. Where two engines are used there are commonly two sets of pumps, one set 
 wrought by a diagonal spear attached to the piston end of the beam, and the other set are wrought by 
 the other end. Steam-engines for mines should be simple in form and proportioned to the work they 
 have to perform. The pump-shaft is divided into lifts, which should not exceed 180 feet each; there 
 is a cistern for the reception of the water, at the top of each lift. Rather than make the diameter ol 
 the pump more than sixteen inches an additional set should be added. Mining work is irregular, 
 more resistance having to be overcome at one time than another. Tredgold gives it as his opinion 
 that an engine does good duty when it raises 70,000 lbs. of ore by the consumption of one pound of coal. 
 The weight to be raised at one draught varies from 3 to 7 hundred weight. Engines at mines are some- 
 times used to break the ore by means of stampers. 
 
 For a more complete treatise on mines, see lire's Dictionary of Mines. For the engines used, see 
 article Pumps and Pumping, as also Engines, in this Dictionary. 
 
 MINT. See Coining. 
 
 MODULUS. The modulus of the elasticity of any substance is a column of the same substance, 
 capable of producing a pressure on its base which is to the weight causing a certain degree of compres- 
 sion, as the length of the substance is to the diminution of its length. 
 
 The modulus of elasticity is the measure of the elastic force of any substance. 
 
 A practical notion of the modulus of elasticity may be readily obtained. Let c be the quantity a bat 
 
420 
 
 MODULUS. 
 
 of wood, iron, or other substance, an inch square and a foot in length, would be extended or diminished 
 oy the force /; and let l be any other length of a bar of equal base and like substance ; then 
 1 : l : : t : A, or 1 c = A, the extension or diminution in the length l. 
 
 The modulus of elasticity is found by this analogy : as the diminution of the length of any substance 
 is to its length, so is the force that produced that diminution to tlie modulus of elasticity. Or, denoting 
 the weight of the modulus in lbs. for a base of an inch square by m \ it is 
 
 And, if to be the weight of a bar of the substance one inch square and one foot in length ; then, if M ba 
 the height of the modulus of elasticity in feet, we have 
 
 — M. 
 
 When a force is applied to an elastic column of a rectangular prismatic form in a direction parallel 
 to the axis, the parts nearest to the line of direction of the force exert a resistance in an opposite direc- 
 tion ; those particles, which are at a distance beyond the axis, equal to a third proportional to the 
 depth, and twelve times the distance of the line of direction of the force, remain in their natural state ; 
 and the parts beyond them act in the direction of the force. 
 
 The weight of the modulus of the elasticity of a column being in, a weight bending it in any manner 
 f the distance of the line of its application from any point of the axis D, and the depth of the column d, 
 (H 2 
 
 the radius of curvature will be — — - . 
 
 1-2 D/ 
 
 If a beam is naturally of the form which a prismatic beam would acquire, if it were slightly bent by 
 a longitudinal force, calling its depth d, its length l, the circumference of a circle of which the diameter 
 is unity c , the weight of the modulus of elasticity m, the natural deviation from the rectilinear form a', 
 and a force applied at the extremities of the axis f the total deviation from the rectilinear form will be 
 
 , d 2 c 2 A in 
 
 ^ d 2 c 2 m — 12 l 2 f 
 
 Scholium — It appears from this formula, that when the other quantities remain unaltered, a' varies 
 in proportion to A, and if A = O, the beam cannot be retained in a state of inflection, while the denomi- 
 nator of the fraction remains a finite quantity : but when d 2 c 2 in = 12 Pf a' becomes infinite, whatever 
 may be the magnitude of A, and the force will overpower the beam, or will at least cause it to bend so 
 
 ( f/ c\ ^ 
 
 -f) * 1 
 
 d 2 
 
 8225 -yin, 
 
 which is the force capable of holding the beam in equilibrium in any inconsiderable degree of curva- 
 ture. The modulus being known for any substance, we may determine at once the weight which a 
 given bar nearly straight is capable of supporting. For instance, in fir wood, supposing its height 
 10,000,000 feet, a bar an inch square and ten feet long may begin to bend with the weight of a bar of 
 
 the same thickness, equal in length to ‘8225 X ^ pm ^ 10,000,000 feet, or 571 feet; that is, with 
 
 a weight of about 120 pounds ; neglecting the effect of the weight of the bar itself. In the same man- 
 ner the strength of a bar of any other substance may be determined, either from direct experiments on 
 
 771 I? I 
 
 its flexure, or from the sounds that it produces. If/= — , = ’8225 n, and — = (’8225 n ) = -907 
 
 y/ n ; whence, if we know the force required to crush a bar or column, we may calculate what must be 
 the proportion of its length to its depth, in order that it may begin to bend rather than be crushed. 
 
 The weight of the modulus of the elasticity of a bar is to a weight acting at its extremity only, as 
 four times the cube of the length to the product of the square of the depth and the depression. 
 
 If an equable bar be fixed horizontally at one end, and bent by its own weight, the depression at the 
 extremity will be half the versed sine of an equal arc in the circle of curvature at the fixed point. 
 
 The height of the modulus of the elasticity of a bar, fixed at one end, and depressed by its own weight, 
 is half as much more as the fourth power of the length divided by the product of the square of the 
 depth and the depression. 
 
 The depression of the middle of a bar supported at both ends, produced by its own weight, is five- 
 sixths of the versed sine of half the equal arc in the circle of least curvature. 
 
 The height of the modulus of the elasticity of a bar, supported at both ends, is of the fourth power 
 of the length, divided by the product of the depression and the square of the depth. 
 
 From an experiment made by Mr. Leslie on a bar in these circumstances, the height of the modulus 
 of the elasticity of deal appears to be about 9,328,000 feet. Chladni’s observations on the sounds of fir 
 wood afford very nearly the same result. 
 
 The modulus of elasticity has not yet been ascertained in reference to so many subjects as could be 
 wished. Professor Leslie exhibits several, however, as below. That of white marble is 2,150,000 feet, 
 or a weight of 2,520,000 pounds avoirdupois on the square inch ; while that of Portland stone is only 
 1,570,000 feet, corresponding on the square inch to the weight of 1,530,000 lb. 
 
 White marble and Portland stone are found to have, for every square inch of section, a cohesive 
 power of 1811 lb. and 857 lb.; wherefore, suspended columns of these stones, of the altitude of 1542 
 and 945 feet, or only the 1394th and 1789th part of their respective measure of elasticity, would be 
 torn asunder by their own weight. . . . 
 
 Of the principal kinds of timber employed in building and carpentry, the annexed table will exhibit 
 
MORTAR. 
 
 421 
 
 their respective modulus of elasticity, and the portion of some of them 'which limits their cohesion, oi 
 which lengthwise would tear them asunder. 
 
 3.600.000 
 
 5.100.000 
 '7,400,000 
 6,000,000 
 
 5.100.000 
 
 6 . 200.000 
 4,350,000 
 
 Teak 
 
 .... 6,040,000 feet 
 
 168th. 
 
 Oak 
 
 .... 4,150,000 feet 
 
 144th. 
 
 Sycamore 
 
 .... 3,860,000 feet.' 
 
 108 th. 
 
 Beech 
 
 .... 4,180,000 feet 
 
 107th. 
 
 Ash 
 
 .... 4,617,000 feet 
 
 109th. 
 
 Elm 
 
 .... 5,680,000 feet 
 
 146th. 
 
 Mernel fir 
 
 8,292,000 feet 
 
 
 Christiana deal 
 
 .... 8,118,000 feet 
 
 146th. 
 
 Larch 
 
 .... 6,096,000 feet. 
 
 121st. 
 
 feet. 
 
 Steel 9,300,000 
 
 Bar-iron 9,000,000 
 
 Ditto 8,450,000 
 
 Yellow pine 9,150,000 
 
 Ditto 11,840,000 
 
 Finland deal 6,000,000 
 
 Mahogany *7, 500, 000 
 
 Rosewood 
 
 Oak, dry 
 
 Fir bottom, 25 years old . 
 
 Petersburg deal 
 
 Lancewood 
 
 Willow 
 
 Oak 
 
 Annexed we give a table of the modulus of cohesion, or the length in feet of any prismatic substance 
 required to break its cohesion, or tear it asunder. 
 
 feet. 
 
 27.000 
 8,000 
 6,700 
 
 79.000 
 
 14.000 
 970 
 144 
 300 
 
 7,300 
 
 Teak 
 
 12,915 lb 
 
 36,049 feet. 
 
 Oak 
 
 11,880 1b 
 
 32,900 feet. 
 
 Sycamore 
 
 9,630 lb 
 
 
 Beech 
 
 12,225 Hi 
 
 38,940 feet. 
 
 Ash 
 
 14,130 lb 
 
 
 Elm 
 
 9,720 lb 
 
 39,050 feet. 
 
 Mem el fir 
 
 9^540 lb 
 
 
 Christiana deal 
 
 12,346 lb 
 
 
 Larch 
 
 12,240 lb 
 
 42,160 feet. 
 
 feet. 
 
 Tanned cow’s-skin 10,250 
 
 calf-skin 5,050 
 
 horse-skin 7,000 
 
 cordovan 3,720 
 
 sheep-skin 5,600 
 
 ITntanned horse-skin 8,900 
 
 Old harness of 30 years 5,000 
 
 Hempen twine 75,000 
 
 Catgut, some years old 23,000 
 
 Garden matting 
 
 Writing-paper, foolscap 
 
 Brown wrapping-paper, thin 
 
 Bent grass, (holcus) 
 
 Whalebone 
 
 Bricks, (Fenny Stratford) — 
 
 (Leighton) 
 
 Ice 
 
 Leicestershire slate 
 
 MOMENTUM, in mechanics, is the same with impetus, or quantity of motion, and is generally esti- 
 mated by the product of the velocity and mass of the body. This is a subject whicJi has led to various 
 controversies between philosophers, some estimating it by the mass into the velocity, as stated above, 
 while others maintain that it varies as the mass into the square of the velocity. But this difference 
 seems to have arisen rather from a misconception of the term, than from any other cause. Those who 
 maintain the former doctrine, understanding momentum to signify the momentary impact ; and the 
 latter, as the sum of all the impulses till the motion of the body is destroyed. See Force. 
 
 MORTAR. A mixture of slaked lime in the state of paste with sand ; it possesses the property, 
 when spread in thin layers between bricks, of gradually hardening to the consistence of limestone, and 
 thus cementing the bricks together. In order to understand the principles upon which mortar is mixed, 
 it is necessary to become acquainted with certain facts which here exert the greatest influence. 
 
 Conditions of hardening. — Simple lime, in the state of paste, likewise hardens, but only to form a 
 loose mass of too slight consistency to bind the parts of a wall or building firmly together. It is only 
 when the layer of lime forms a very thin stratum, as between two polished stones, that a firm and solid 
 cement is produced. The lime must be prevented from forming masses of any considerable thickness, 
 as these always possess a very slight degree of cohesion. The lime attaches itself firmly only to the 
 surface of the building-stones, which differ from it in character, and this surface should be extended, as 
 it were, by mixing a, granular powder with the lime. This leads directly to the object and use of sand 
 in the mortar, which is only intended to bring about more intimate contact between the surfaces of the 
 stones and the lime. The shape of the bricks and hewn stones is so irregular, that crevices of a line at 
 least, and in hewn stones often of an inch in width, are left between them when laid one upon another. 
 Lime alone placed between the stones, would consequently be in layers of a line to an inch in thickness, 
 and in such masses would never bind. If, however, a sandy powder of any kind of stone is mixed with 
 it, the mass of lime is thus divided into a great number of thin layers, or, as it were, fills up the inter- 
 stices between the sand, and finding everywhere points of attachment, binds the grains of sand together, 
 and extends this binding action to the stones themselves. 
 
 It is further known that even the best mortar, when quickly dried, as, for instance, on the stove, does 
 not harden, but remains friable and porous. Although, therefore, mortar placed under water remains 
 
422 
 
 MORTAR, 
 
 porous and 'will not bind, yet the action of moisture is essential to make it harden in the air. Lastly, th* 
 tree access of air is also absolutely necessary to the setting of mortar. 
 
 Proportions of mixture. — When these facts are borne in mind, the rules to be observed in mixing 
 mortar will be obvious. Although many kinds of stone in the form of coarse sand are applicable for 
 making mortar, as limestone, for instance, yet quartz-sand is always most easily obtained; the grain ol 
 the sand, however, is a matter of some importance. Very fine sand renders the mortar too dense, and 
 impedes the free access of air ; sand in grains of the size of hay-seed, particularly if it is angular or 
 sharp, is very good ; the interstices become too large to be entirely filled with lime if very coarse sand 
 is employed. It is then advantageous, particularly when irregularly shaped building-stones are used, 
 to mix two kinds of sand together, coarse and fine. Fine sand can only be mixed with the lime when 
 the mortar is intended for a thin coating upon the surface of walls, &c. The more irregular the sand is, 
 the better. The proper proportion of sand and lime is a most important point in preparing mortar; 
 and the good quality and solidity of the mortar are more influenced by it than by any thing else. 
 Errors committed in the mixing can never be subsequently corrected. 
 
 As a general rule, the lime should be sufficiently fine to cement all the grains of sand together, but 
 should form at the same time the thinnest possible stratum between them. The surfaces of the grains 
 of sand, or the interstices between them, should therefore be only just covered with the lime in a half- 
 liquid state, and no more. The rule might be laid down in the following terms: let as much lime be 
 mixed with the sand as it will take up without having its volume increased. Practically, about 3 to 4 
 cubic feet of sand (or 6 times the weight) are added to 1 cubic foot of half-liquid lime, provided the lime 
 be fat, or very fat ; poor lime, which may be viewed as already containing a certain portion of sand, will 
 not bear the addition of more than 2£ cubic feet of sand to 1 cubic foot of lime. The sand should be 
 pure, i. e., it should not contain too much iron or clay, and least of all, bog-earth, or vegetable matter. 
 
 Hardening or setting — time required. — Although mortar sets sufficiently in a few days, or weeks, to 
 enable a wall to withstand pressure and the like, yet the hardening proceeds so slowly and gradually, 
 that it only attains its maximum (in which case a wall appears as if constructed of one piece of stone) 
 after years, or even centuries. The apparent superiority of mortar in olden times over that in the 
 present, is solely attributable to the longer time which has been allowed it to harden and set, as no 
 essential difference can be traced in the mixture of the ingredients. Although we see, on the one hand, 
 that old buildings can only be destroyed with the aid of powder, yet it must not be forgotten on the 
 other, that in some buildings the direct converse is observed, and that the durable portions only have 
 been enabled to withstand the ravages of time, while the weaker and less durable parts have long since 
 disappeared. In the same manner, it is probable that some buildings erected in our own age will stand 
 forward to posterity as patterns of solid architecture, just as those of the middle ages and of the ages of 
 Grepce and Rome appear to us at preseut. 
 
 Cause of setting. — The hardening of mortar upon exposure to the air is not so easily explained as 
 would at first appear. It has even been disputed whether it is the result of mere physical (mechan- 
 ical) or only of chemical agencies. And it appears probable, when every thing is taken into consider- 
 ation, that the hardening cannot be attributed to any one cause in particular, but to all collectively, and 
 in such a manner that the formation of a silicate of lime and crystallization are the causes of the durable 
 solidity and conversion into stone, while the absorption of carbonic acid induces the rapid setting of 
 the mortar. 
 
 The hydraulic mortar employed in building the Eddystone lighthouse was mixed by Smeaton from 
 equal proportions of lime, slaked to powder, and Puzzolana. Trass and Puzzolana are generally mixed 
 with one-half their weight of lime, as was the practice amongst the Romans. It is desirable to ascer- 
 tain the best proportions by experiment in all cases where no certain knowdedge of the nature of the 
 two substances can be obtained. 
 
 Good hydraulic mortar, whether made from natural limestone or composed of lime and cement, should 
 not show any tendency to crack when hardened under water, even when no sand is mixed with it. It 
 then forms a very dense and solid mass, which, in a short time, neither suffers water to permeate it, nor 
 is attacked by the water, but acquires a considerable degree of hardness. For this reason, it is well to 
 use nothing but hydraulic mortar for those parts of walls which are constantly under water. If the 
 mortar is not only required to harden, but also to bind well, a very important point must never be neg- 
 lected, and that is to moisten the surfaces of the stones to which the mortar is to be applied. When 
 this is not done, the surface of the stone (by its power of absorbing moisture) dries the mortar, and pre- 
 vents proper adhesion from taking place ; the joint then remains open to a greater or lesser extent. 
 
 It does not by any means follow, that because hydraulic mortar is the only durable material for 
 building under water, it cannot consequently be used for dry walls. It is, on the contrary, of the great- 
 est service wherever protection is required against the infiltration of moisture and damp ; and dwellings 
 or buildings can often be rendered very much less damp by a judicious application of a hydraulic coat- 
 ing ; a layer of this kind, when once hardened, is not calculated, like ordinary mortar, to attract moisture 
 and allow it to pass through. The hydraulic mortar must, of course, when used for covering dry walls 
 or otherwise, be kept moist and watered, until it has acquired its proper degree of hardness. If this is 
 not attended to, a soft, friable, useless coating is the certain result. If moisture enters from below, for 
 instance, between the wall and the coating of mortar, it will continue confined there in consequence of 
 the impenetrability of the latter, which, on the occurrence of a frost, will most certainly peel off and be 
 destroyed. Care must also be taken that the mortar does not dry up of itself immediately in the air, in 
 which case it contracts and cracks. It is, therefore, necessary to add sand or some other substance which 
 obviates the shrinking. Hydraulic mortar will bear a very considerable quantity of sand without injury 
 to its hardness, even as much as one and a half times its own weight and more. This addition, there- 
 fore, is important in an economical point of view. The grain of the sand employed, however, requires 
 attention, as was the case with ordinary mortar ; sharp, angular sand is decidedly preferable to blunt, 
 taunded sand, and it is better to use a mixture of coarse with fine sand, than that the sand should be 
 
MORTAR. 
 
 423 
 
 all of the same sized grain. The sand should likewise be as free as possible from earthy particles and 
 dust. In mortar composed of lime and cement, the rule is, to proportion the sand to the quantity ol 
 cement used. Slaked lime will not bear more than a certain quantity of these substances, which quan- 
 tity must not be exceeded, the cement itself being for the greater part inactive, and playing the pari 
 of sand. 
 
 Hydraulic mortar that sets with sufficient rapidity, and to which a proper proportion of sand has been 
 added, may be employed for casting tolerably massive objects, which are not subject to crack when dry. 
 This enables hydraulic mortar to be employed for architectural ornaments which then combine great 
 sharpness with durability, are very light as compared with similar figures of sandstone, and have the 
 great advantage of being easily multiplied. 
 
 A similar application is that for casting water-pipes, on the spot where they are required, as pro- 
 posed by Gasparin. The mould employed is a linen hose, like those attached to the fire-engines, a few 
 meters in length, which is filled with water and closed at both ends. A thick kind of bolster is thus 
 produced, over which sand is sifted, and it is then laid upon a deposit of hydraulic lime and covered, 
 by pouring over it the same substance. When the whole has hardened, the hose is drawn forwards, 
 about the length of one foot being left inserted in the tube, and a fresh length is cast. Water-courses 
 thus constructed must, however, have a certain amount of fall, or the sand cannot be washed out, and 
 will impede the delivery of the water. 
 
 When hydraulic lime is mixed with small stones, or with shingles from the bed of a river, or the sea, 
 walls can be directly constructed of it, and a mass is obtained which resembles the erections with ordi- 
 nary mortar, and is called beton by the French. 
 
 At Toulon a mixture was used for the construction of the harbor consisting of 3 parts lime, 4 Puzzo- 
 lana, 1 smithy ashes, 2 sand, and 4 parts of rolled stones or shingles. 
 
 The great strength of walls constructed with hydraulic mortar is most clearly shown by the experi- 
 ments undertaken with a view to break beams constructed of brick-work. A 25 feet long and 2-J- feet 
 wide beam, constructed with 19 layers of bricks, bound together by Roman cement, in which, here and 
 there, parallel strips of iron were inclosed, was capable of bearing, when supported at both ends, a 
 weight of 22 tons, suspended from the middle, before it showed signs of fracture. 
 
 Mr. Frederick Ransome has lately taken a patent for preparing different articles with a kind of vitri- 
 fied cement. The following is the principle of his process : 
 
 Flints are suspended in wire baskets in a boiler of caustic alkali, which is heated to about 300° Fahr, 
 under a pressure of 50 to 80 pounds per square inch. A solution is thus obtained of silicate of soda o 
 potash, (of a specific gravity of from about 1'3 to 1'6.) 
 
 This is the cementing substance, the composition of which is said to be 
 
 Silica 20'43 
 
 Soda 2T05 
 
 Water 52-52* 
 
 100-00 
 
 One part of this liquid cement is ground up with one part of pipe-clay and one part of powdered flint, 
 which are well mixed in a pug-mill with 10 parts of sand or road-drift. The mixture is pressed into 
 plaster moulds, and is then dried in the air on flat surfaces, to prevent warping. It can now be handled, 
 and is stove-dried previously to being placed in a potter’s kiln, where it is heated slowly for 24 hours, 
 and up to a fair red-heat for 24 hours more, and then gradually cooled during 5 days. 
 
 This gradual annealing is essential, because the silicate of soda, during the firing, takes up more silica 
 and alumina from the flint and clay, forming a true insoluble glass, which would crack if not properly 
 annealed. The stone is not affected by boiling in nitric acid, which proves that an insoluble glass has 
 been formed. 
 
 Sand and road-drift produce a white stone suitable for the face of ornaments, which are backed up 
 with composition made of loam and silicate of soda. 
 
 According to the quantity of silicate of soda used, the stone may be either porous or impervious. It 
 sufficient is used to fill up all the interstices between the grains of sand, the stone will be impervious. 
 Some of Mr. Ransome’s stone has been exposed for two years to the weather without the sharp edges 
 being in the slightest degree injured ; many porous stones will stand weather and frost better than im- 
 pervious ones, and it is therefore still a question whether this stone will resist the action of air and rain 
 loaded with sulphurous acid, as is the case in London. Some of the blocks of stone quarried at the 
 island of Portland for St. Paul’s Cathedral, and left there, are now quite perfect, whilst the stones in the 
 Cathedral have become very much decayed. 
 
 Mr. Ransome in his patent, 22d October, 1844, merely directs the stone to be dried at 212° Fahr., or 
 at a higher temperature, and does not say any thing about baking it ; he directs about one-sixth part 
 of the silicate to be used in the mixture. f It was stated at the Institution of Civil Engineers, that slabs 
 of 7 feet long by 9 in. X 3 in. had been made perfectly flat and true, and that the reason they did not 
 warp was, that the particles of sand were in contact with one another, and the cement only filled the 
 interstices. If, on the contrary, too much cement were used, the shrinking of the cement would warp 
 the slabs. Square blocks of this stone, we believe, may be procured for 3s. per cubic foot in favorable 
 localities for the materials, fuel, (fee., but the principal application for which it is intended is for orna- 
 ments, as mouldings, rosettes, coats of arms, mullions, (fee. ; for elaborate forms may be given to it at 
 very little more expense than is required for the simplest form. Terra cotta has been used for these 
 purposes, but it warps in baking, and produces so many waste pieces that it becomes more costly and 
 B less correct than stone worked by hand in the usual manner. 
 
 * Faraday, however, states the amount of water to be 75 per cent, 
 t See Chem. Gazette, voi. iii. p. 360. 
 
424 
 
 MORTISING MACHINE. 
 
 Mr. Rockwell has also proposed a plan for making large masses, slabs, and pipes from stone and 
 cement ; but bis invention does not apply to the manufacture of cubical blocks. 
 
 He uses fragments of stone as large as will go freely into the mould, mixed with other smaller frag- 
 ments, of various sizes, to fill up the interstices as much as possible, the remaining space being occupied 
 by the cement, composed of chalk and Thames mud burnt together. 
 
 One part of this cement is mixed with eight or more parts of fragments of stone, and wetted with the 
 smallest quantity of water sufficient to moisten the whole ; a portion of the mixture is then put into the 
 mould to a depth of 1 4 inch, and rammed down by hammers or monkeys ; another 14 inch is then added 
 and rammed down, and so on. The mould is perforated, and, although so little water has been used, 
 it oozes out at all parts, showing that the effect of the ramming is to bring the particles of stone into 
 much closer contact than could be done by any simple pressure. When taken out of the mould, the 
 stone is hard enough to ring, and is fit for use in two days ; it becomes still harder by exposure to air 
 or water for some months. 
 
 New Portland stone fragments cannot be used for this conglomerate, because they crush into powder 
 under the hammer ; old Portland stone, which has become hardened by exposure, answers very well, 
 and makes an artificial stone of greater specific gravity than Portland stone itself. The cement is 
 harder than the Portland stone. Flaws, repaired by the mixture laid in with a trowel, are much softer 
 than the cement in the body of the stone which has been consolidated by the ramming. The moulds 
 are made of metal and are very expensive, which prevents the material being applied to ornamental 
 purposes. 
 
 Separate pieces of stone can be joined by well ramming or caulking in the composition between 
 them. For this purpose, of course, the pieces should be firmly fixed before beginning to caulk between 
 them. Mr. Buckwell states that he could execute entirely in his artificial stone the ordinay system of 
 sewage, with improvements, at the same cost as the present mode of executing it in bricks. It may, 
 therefore, be doubted whether it would be advisable to employ it. A new arrangement of sewage, 
 which he proposes, would cost §12 in his stone, for what would cost §75 in brick-work; but it does not 
 as yet appear why, in one case artificial stone should cost as much, and in the other only one-sixth the 
 price of brick. 
 
 An illustration of the effect of percussion in consolidating materials may be taken from the fact that 
 concrete, a mixture of gravel and lime, sets harder and better the greater the height from which it is 
 allowed to drop into its place : in building the Royal Exchange, it was shot in from a platform 30 feet 
 above the foundation. It seems probable that concrete might be rendered still harder by mixing it 
 with rather less water, and ramming it well in its place. In Malta the roofs of the houses consist of 
 flag-stones placed in a nearly horizontal position ; over the flag-stones a bed of fragments of stone and 
 a little clay is laid, which is moistened with water, and beaten and rammed until nearly dry ; it is then 
 covered with a layer of cement, formed of 4 parts of lime to 3 of Puzzolana, moistened with water, and 
 well beaten down until it begins to dry ; this again is covered with a layer of dry stone fragments to 
 prevent the sun from cracking it, which being swept off after a few days, a fine smooth impervious roof 
 is obtained. 
 
 Hydraulic fresco-painting . — In conclusion, we must notice a discovery of Fuchs and Schlotthauer, 
 which was lately communicated to the Academy at Munich, and which has reference to a new mode oi 
 fresco-painting. While the fixing of the colors in the antique as well as in the modern fresco-paintings 
 is due to the hardening property of caustic lime, when exposed to the atmosphere, the colored surface 
 upon this new method is converted into a silicate of lime. The two older methods stand, therefore, in 
 the same relation to the new one, as ordinary to 
 hydraulic mortar. While fresco-paintings of the 
 former kind are not very durable, (except in cases, 
 us at Pompeii, where their preservation is due to 
 the entire exclusion of light and air,) and artists 
 have reason to mourn over the destruction of the 
 greatest master-pieces ; those obtained upon the 
 now principle are capable not only of withstand- 
 ing the action of water, weak acids, and alkalies, 
 but also the great changes of climate during a se- 
 vere German winter without injury to the freshness 
 of the coloring ; and the colors are so firmly at- 
 tached to the ground that they exhibit no tendency 
 to separate from it themselves, nor can they be 
 removed by mechanical agency. The particulars 
 of the process have not been made known, but it 
 appears probable that it is dependent upon the 
 siiicification of the lime mortar, by means of a 
 solution of an alkaline silicate, of which we have 
 previously spoken under soluble glass. 
 
 MORTISING MACHINE. Fig. 2846 repre- 
 sents a mortising machine invented and patented 
 by A. Swingle, formerly of Texas, now of Boston. 
 
 A A are the legs, B the bench ; C is a set-screw 
 for the out-and-in movement of the bench, and D 
 for the lateral, in any kind of work. E is a hub to 
 be mortised ; it is mounted on centres turned by 
 the handle F, and there is a retaining ratchet and wheel H on the nigh side. There is a rest below the 
 hub, operated by a steadying set-screw I. J, inverted, is a hollow augur, or rather hollow chisel withic 
 
MOTION. 
 
 425 
 
 ■which is the augur ; and the movement of the latter is followed by the box-shaped chisel, so that the 
 result is a square hole or mortise. The augur inside receives a very rapid motion from a bevel-wheel, 
 geering into a pinion which drives the spindle K of the augur, a is a pulley to drive the wheel O. M 
 is a lever, and by flanges the spindle is made steady to the back of the frame, and works down in guide- 
 collars. When the hub, or whatever it may be, is in a correct position, the spindle K of the augur is 
 set in motion, and the operator gently brings down the weighted lever M, cutting out the rectangular 
 mortise. There is but little work for the outside chisel of the augur to perform. 
 
 The lever rests on the top of the spindle, and it (the spindle) works by feather and groove to run 
 down through its geer-pinion, to follow the cut to the bottom of the mortise. These machines are highly 
 recommended by those who have used them. 
 
 2847. 2843. 
 
 MORTISING MACHINE. Figs. 2841 and 2848 represent a machine manufactured by W. R. A 
 A. Inslee, Newark, N. J., and from the simplicity of its plan it is much less liable to get out of order 
 than others of a more complicate character. 
 
 The action of the machine is sufficiently obvious. 
 
 MOTION, in mechanics, is a change of place, or it is that affection of matter by which it passes from 
 one point of space to another. Motion is of various kinds, as follows : Absolute motion is the absolute 
 change of places in a moving body, independent of any other motion whatever — in which general sense, 
 however, it never falls under our observation. All those motions which we consider as absolute are, in 
 fret, only relative, being referred to the earth, which is itself in motion. By absolute motion, therefore, 
 we must only understand that which is so with regard to some fixed point upon the earth, this being the 
 sense in which it is delivered by writers on this subject. Accelerated motion is that which is continually 
 receiving constant accessions of velocity. Angular motion is the motion of a body as referred to a 
 centre, about which it revolves. Compound motion is that which is produced by two or more powers 
 acting in different directions. Uniform motion is when the body moves continually with the same ve- 
 locity, passing over equal spaces in equal times. Natural motion is that which is natural to bodies, or 
 that which arises from the action of gravity. Relative motion is the change of relative place in one or 
 more moving bodies : thus two vessels at sea are in absolute motion (according to the qualified signifi- 
 cation of this term) to a spectator standing on the shore, but they are only in relative motion with 
 regard to each other. Retarded motion is that which suffers continual diminution of velocity, the laws 
 of which are the reverse of those for accelerated motion. 
 
426 
 
 MOTION. 
 
 Table of the Analysis of Motion. 
 
 Rectilinear motion continued in 
 
 Circular motion continued in 
 
 Rectilinear 
 
 Circular... 
 
 Continued ... Figs. 1, 2, 3, 4, 5. 
 
 Alternate 
 
 ( Figs. 6, 7, 8, 9, 10, 
 Continued 4 11, 12, 13, 14, 
 
 ( 15, 16, 17, 18, 19. 
 
 Alternate . 
 
 r 
 
 Rectilinear alternate 
 
 .. Figs. 20, 21, 22, 23, 24. 
 
 Figs. 25, 26, 27, 28, 29, 
 30, 31, 32, 33, 34, 
 
 - 35, 36, 37, 38. 39, 
 
 40, 41, 42, 43, 
 
 44, 45. 
 
 Circular 
 
 | Continued . 
 Alternate.. 
 
 ( Figs. 46, 47, 48, 49, 50, 
 4 51, 52, 53, 54, 55, 
 
 ( 56, 57, 58. 
 
 f Figs. 59, 60, 61, 62, 63, 
 I 64, 65, 66, 67, 68, 69, 
 | 70, 71, 72, 73, 74, 
 
 L 75, 76. 
 
 Alternate rectilinear motion con- * 
 
 1 Rectilinear alternate 
 
 1 circular alternate 
 
 j Figs. 77, 78, 79, 80, 81, 
 
 
 
 
 •') 82,83,84,85,86. 
 
 
 Alternate circular motion con- j 
 tinued in j 
 
 - Circular alternate 
 
 Figs. 87, 88, 89, 90, 91. 
 
 
 Supplement 
 
 
 j Figs. 92, 93, 94, 95, 96, 
 ' l 97, 98. 
 
 
MOTION. 
 
 427 
 
428 
 
 MOULDING MACHINE. 
 
 MOULDING MACHINE. This invention consists of certain mechanical arrangements for producing 
 architectural, cabinet, or other mouldings. Our engraving represents an end elevation of the machine, 
 which, with the aid of the letters of reference, will be readily understood. A, is a cast-iron bed-piece 
 with V grooves, and constructed in some respects similar to planing machines now in use for planing 
 iron, &c., having a driving-screw placed in the centre of the bed-piece, so as to give a slow alternating 
 motion to the travelling-table, when power is applied thereto. The ordinary reversing geer is em- 
 ployed, the construction of which is well known ; B is the bed or traversing-table which is shown in 
 section, for the purpose of more clearly representing the various arrangements in detail, such as the 
 mode of fastening the planks of wood to the table by the means of lateral clamps inserted in their 
 sides; JJ the position of the driving -screws together with the inverted Y rail, and standards KK; 
 C is the driving-screw, also shown in section, and which passes longitudinally through the machine from 
 end to end, in geer with the bed or table by a nut, or any other suitable means usually applied to such 
 purposes when reversing. There are two vertical standards, supporting in bearings the bridge E, with 
 the cutter-bars, or mandrils, attached. Each of these standards contains a spring of the same pitch, 
 geering into, and attached to the bridge, so that by turning the horizontal bar F, both screws are made 
 
SHEET-METAL MOULDING MACHINE. 
 
 429 
 
 2947. 
 
 to revolve at the same rate, and the bridge is thereby caused to ascend and descend as may be re- 
 quired; G is a horizontal bar, which revolves rapidly in its bearings HH, and carries a number 01 
 cutters or chisels, each having its cutting edge so shaped as to produce the required mouldings, or any 
 parts thereof, which can be produced by revolving cutters on a horizontal shaft. Motion is communi- 
 cated to this axis by bands from an overhead power-wheel. Its course, after leaving the power-wheel, 
 
 is first directed down to a tightening pulley, which is 
 clamped on to a part of the standard frame on one side, 
 having a vertical slot therein for the purpose of enabling 
 the operators at auy time to obtain the requisite tension ; 
 it then passes up and over the upper half of one groove 
 of the cutter-pulley, down again at the back, and over the 
 driving-pulley : it is then pressed in at the starting point 
 to make the endless band. 1 1 are the chisels or cutters, 
 which are mounted upon the horizontal shaft G, which ad- 
 mit of being arranged and set up in any convenient or 
 necessary form and number suitable to the production of 
 compound mortises ; each chisel being of the most simple 
 form and construction, having its cutting edge shapied to 
 form the numerous mouldings, either simple or compound 
 by either using them separately or in conjunction with eact 
 other, as the case may require ; L L are bosses cast on the 
 standard on each side and on each end, on a level with 
 the surface line of the bed or table B. These bosses 
 are bored to receive a vertical rod through each, the 
 
 lower end of which has a thread run upon it, in geer 
 with a nut and a hand-wheel MM, whilst the upper end 
 forms a shackle or forked head, (but which is not shown in the above view.) it being readily understood 
 to constitute merely a single bearing to carry a horizontal shaft from one side of the machine to the other 
 transversely, on which elastic friction rollers are mounted: the object of such bearings being that when 
 a different moulding is to be substituted for the one in the course of formation, the shaft containing the 
 corresponding shaped friction rollers by the mouldings last completed may easily be exchanged for that 
 of any other, by removing it from the forked head in which it revolves. At the back of the bridge E 
 a horizontal and vertical slide is fixed, having a slot parallel to the bed of the machine, for the purpose 
 of carrying two traversing cutter-heads, affixed to which, through the intervention of revolving man- 
 drils, are the cutters which work at any angle to the bed or table, as well as on the same surface level, 
 as the cutters 1 1. The cutters thus referred to receive their direct motion from the power-wheel over 
 head, independently of other parts of the machine, by an endless rope or chain passing round the 
 wheel mounted in the cutter-heads in such a manner that when this part of the apparatus is not re- 
 quired to work in connection with the other it can be thrown out of geer at any time, even while tha 
 running mouldings are in action. 
 
 2949. 
 
 2950. 
 
 2948. 
 
 In connection with the above the inventor uses the bevelled cone-wheels to produce rotary motion 
 to give full effect to the cutting tools 1 1, by the motion of the vertical mandril working in a broad beam 
 the cutter-head, while the work to be cut is held down nicely by vulcanized India-rubber rollers. The 
 principal feature in the invention is the revolving horizontal bar, whereby, like borders made of type, 
 the inventor is enabled to make compound and various patterns by simple chisels, by their transposition. 
 
 SHEET-METAL MOULDING MACHINE, by Mr. It. Roberts, of Manchester. This machine, Figs. 
 2951-2955, has two shafts B and B', which project beyond one of the side-frames in which the lower 
 shaft B turns ; the upper shaft B is mounted in a balance swing-frame, and is connected by spur geer 
 with the lower shaft in such a way that the distance between the shafts may be adjusted to any re 
 
430 
 
 MULE. 
 
 quired extent, without altering the depths of the wheels in geer. On the projecting ends of thes* 
 shafts, the rollers D E are put, with which the mouldings are to be formed ; the lower roller is in one 
 piece only, but the upper roller is made in one or more parts transversely, as may be best adapted to 
 form the required mouldings, as shown in 
 the enlarged figure : the which parts, 
 when more than one, are made to ap- 
 proach each other by being slid along the 
 shaft B', which is hollow, by means of a 
 screw F that acts within on the back part 
 of the top roller D by means of a cotter, 
 which passes through the shaft and the 
 screw, and on the front part by a nut f 
 which is screwed, from time to time, by 
 hand. 
 
 The advantage of making the rollers in 
 two or more parts is, that it allows the 
 metal to be gradually compressed side- 
 ways as well as vertically, and avoids 
 puckering. The curved mouldings shown 
 in the engraving were made on the first 
 machine of the kind that was constructed, 
 and the straight mouldings on a similar 
 machine subsequently made. Almost any 
 degree of curvature can be given to the 
 moulding, by means of the third roller H, 
 which, with its shaft and sliding bearings 
 J, is lowered by the geering h, Fig. 2951, in front of the pair of rollers to produce the required curvature, 
 
 The engravings A, Fig. 2951, apd A', Fig. 2953, are representations of two pair of rollers for form- 
 ing simultaneously the cap mould of each of the two brass domes for locomotive engines ; the rollers 
 A, Fig. 2951, being for the purpose of creasing the metal, and the rollers A' for finishing the two 
 cap-moulds, which may be afterwards divided in the middle by a lathe or with a saw. Two mouldings 
 are in this case made together, owing to the peculiar form of the moulding rendering it more facile to 
 do so than to make one separately. 
 
 Fig. 2950 and 2954 show two pair of rollers for forming the “ astragal,” to which the upper and lower 
 plates of the chimney of a locomotive are riveted ; the rollers B* B" are used in the order the draw- 
 ings are lettered. 
 
 Fig. 2953 shows a pair of rollers for forming the “ base mould,” and Fig. 2949 for forming the body of 
 the brass dome of the locomotive engine, one pair of rollers only being used in both these last men- 
 tioned cases. 
 
 MULE. A machine employed in spinning cotton and other fibrous materials. For producing fine 
 threads, a process analogous to that performed with carded cotton, upon a common spinning-wheel, 
 and called stretching , is resorted to. In tins operation, portions of yarn, several yards long, are forcibly 
 stretched in the direction of their length, with a view to elongate and reduce those parts of the yarn 
 which have a greater diameter and are less twisted than the other parts, so that the size and twist of 
 the thread may become unifprm throughout. To effect the process of stretching, the spindles are 
 mounted upon a carriage, which is moved backwards or forwards across the floor, receding when the 
 threads are to be stretched, and returning when they are to be wound up. The yarn produced by 
 mill spinning is more perfect than any other, and is employed in the fabrication of the finest articles. 
 The sowing-thread, spun by mules, is a combination of two, four, or sis threads. Threads have been 
 nroduced of such fineness that a pound of cotton has been calculated to reach 167 miles. 
 
MULE, SELF-ACTING. 
 
 431 
 
 MULE, Mason's self-acting. This machine, invented by J. W. Mason, of Taunton, Mass., for spinning 
 cotton and other fibrous substances, stands first in the first class of machines. 
 
 Fig. 2956 is an elevation of the mule and carriage. Fig. 2957 an elevation of the other side. Fig. 
 2959 a plan. Fig. 2960 an elevation. Fig. 2961 a longitudinal vertical section, taken through the line 
 X X of Fig. 2959. Fig. 2963 a front elevation. Fig. 2962 a section through the friction-clutch. . Fig. 
 2958 a separate view of the scroll or volute cam. Fig. 2964 a cross lection of the head. The same 
 letters indicate like parts in all the figures. 
 
 A 3 represents a frame properly adapted to the operative parts of the head ; the carriage is not 
 represented, as it is similar to those of other mules. 
 
 A A' A" three pulleys of equal diameter, placed side by side on the main shaft B'. A is the first 
 fast pulley attached to and turning with the shaft B. A' is the second fast pulley, carrying a pinion 
 D, and turning freely on the shaft B. A" a loose pulley placed between the other two, and turning 
 freely on the shaft. A driving-belt passes over these pulleys, and is guided to either of them by a 
 shipper-lever C, that vibrates on a stud-pin U, and connected with a weighted balance-lever C 3 by 
 which the belt is moved from one of the pulleys to either of the other two. At the commencement ol 
 the first series of operations, the belt runs on the first fast pulley A', to give the first series of motions. 
 The pinion J, on the shaft B, communicates a positive and regular motion to the shaft G (which is in 
 connection with the draw collars in the usual manner) by means of the first train of wheels Iv L I, and 
 from the shaft G by the second train of wheels NOPRSX, to the line shaft Y that drives the car- 
 riage by means of endless chains Z, connected with the carriage by one of the links, Z 3 . There is but 
 one of these chains represented in the drawings, and the shaft is shown broken off, as the connections 
 with the carriage present nothing new, and therefore need not be represented. The spindles at the 
 same time rotate by the usual band T, driven by the pulley O', on the same pulley shaft B. This 
 completes the first series of motions, namely, drawing out the carriage, turning the draw rollers and 
 spindles to draw out, spin, and twist the threads. Near the end of the running-out motion of the 
 carriage, the belt is shipped from the first fast pulley A to the loose pulley A", which removes the 
 driving power from these motions. The shifting of the belt is thus effected : the weighted balance-lever 
 C 3 is jointed to the shipper-lever at 2, above the stud-pin 3, on which it vibrates. The lower end ot 
 this balance-lever is T-shaped, and one of its short arms is joined by a fink 4, with a short lever 5, 
 that turns on the stud-pin 6. This lever is also connected by a link d, with another lever p, that 
 turns on a stud-pin e, and this last lever is depressed when the belt is to be shipped by means of a 
 pin a , on a vibrating arm L', on the shaft K' of the wheel that carries the connecting-rod by which 
 the carriage is run in. The balance-lever is by this means carried a little beyond the vertical line, 
 and then carried entirely over by the weight of the lever C 3 . On this shaft, K', and on the opposite 
 side of the frame, there is another arm M', provided with a pin g, which at the same time depresses 
 another lever X', connected by means of a jointed rod li, with an elbow-lever 7, that moves a 
 clutch M on the shaft G, by means of which the cog-wheel I is clutched, which liberates the draw 
 rollers and the second train of wheels that communicate motion to the carriage from the parts that 
 drive the spindles. The clutch M is held open until the belt is again carried to the first fast pulley 
 at the end of the third series of motions by a pin /, on one arm of the balance-lever C 3 , which bears 
 against one side of the arm of the clutch-lever 7, for the lever X', that moves the clutch-lever, is 
 provided with a helical c' attached to it and the frame, for the purpose of forming the clutch the 
 moment that the pin^' of the balance-lever C 3 liberates the clutch-lever 7. The band T' that carries 
 the spindles, and which, as we have before stated, passes round and is carried by the pulley O' on the 
 main shaft B, passes around a guide-pulley R' at one end of the frame, and another S' at the other 
 end, and also around another pulley P' that runs freely on a shaft Q' which slides endwise on its bearings 
 and on the friction pulley, which is prevented from sliding endwise with the shaft by a collar 8, so that 
 when this shaft Q' is moved in one direction, the puliey P' is clutched to it by the friction of the 
 conical surfaces, and when moved in the reverse direction it is unclutched and turns freely on the 
 shaft. This clutching and unclutching is effected by an arm Z 3 , Fig. 2961, on the spindle U' of the 
 shipper-lever C, which embraces a collar on the shaft Q', so that when the shipper C shifts the belt 
 from the first fast pulley A, it at the same time gives the requisite movement to clutch the friction- 
 clutch that connects the spindles with the shaft Q', which will be carried by their momentum ; and as 
 this shaft is connected by the train of wheels X', Y', Z', and C", with a horizontally sliding-rack W', the 
 rack is carried for a short distance in the direction of the arrow, Fig. 2961. When the shipper trans- 
 fers the belt from the first fast to the loose pulley, a clutch D 2 , Fig. 2964, on the shaft D 1 , is 
 shifted by the forked lever f which turns on the stud-pin 10, and is worked by a spur 11 on the 
 balance-lever C 3 , which bears on the end of the volute spring 12 attached to the lever /, the tension of 
 which forces the sliding part of the clutch against the permanent part. The sliding part of the clutch 
 is feathered to the shaft D', v\ hich is carried by a train of wheels C' B' and pinion D on the second 
 fast pulley A', driven by the driving-belt when it is shifted by the shipper that carries it from the first 
 fast pulley A to the loose pulley A" and then to this : the time required for this transfer of the belt 
 by the motion of the shipper being sufficient for the preparative movement. 
 
 So far it has been shown that the second fast pulley carries the shaft D' of the clutch D” a part of a 
 revolution before clutching the pinion E' which geers into the wheel F' that runs the carriage in, (as 
 will be hereinafter described,) this period of time being required to enable the momentum of the spin- 
 dles to run back the rack w' preparatory to the backing-off motion. As the rack w' is carried by the 
 momentum of the spindles in the direction of the arrow preparatory to the backing-off motion it is 
 necessary gradually to arrest this motion, which is effected by a friction-spring brake constructed and 
 connected with the rack in the following manner. To the end of the rack is attached a chain m, which 
 passes over a pulley o, and then around a spin-wheel p, attached to a ratchet-wheel H 2 , and with it 
 turning freely on a rock-shaft n ; and then it passes over another loose pulley D 3 , and to the end of it 
 is susnended a tension weight E 2 , which takes up the slack of the chain. On the said rock-shaft n, and 
 
432 
 
 MULE. SELF-ACTING. 
 
MULE, SELF-ACTING. 
 
 433 
 
 // 
 
 Vol. IL— 28 
 
431 
 
 MULE, SELF-ACTING, 
 
MULE, SELF-ACTING. 
 
 435 
 
 by the side of the ratchet-wheel, there is a cam-plate t, that also turns freely on the shaft, and which is 
 carried in one direction by the ratchet-wheel, when the catch or hand v, which is jointed to the cam- 
 plate, takes into the teeth of the ratchet, the two turning independently of each other in the reverse 
 direction, or in the same direction when the catch or hand is lifted out of the teeth. When the rack is 
 drawn by the momentum of the spindle in the direction of the arrow, the chain in attached thereto 
 
 turns the spur and ratchet wheel in the direction of the arrow ; and the cam-plate is also turned in tne 
 same direction by the catch or hand v. This motion is gradually arrested by the enlarged or scroll form 
 of the cam-plate, which forces out a friction-arm b', one end of which is jointed at a' to an arm of a 
 lever F 3 , attached to the rock-shaft n, the other arm of this lever being connected with the friction b' 
 by a helical spring s. It will therefore be perceived that as the friction- arm is forced out by the cam 
 
29C1. 
 
 436 
 
 MULE, SELF-ACTING. 
 
MULE, SELF-ACTING. 
 
 437 
 
 plate, the tension of the spring increases the friction of the brake on the periphery of the cam-plate, 
 which gradually arrests the motion of the parts in connection with the rack W, and of necessity the 
 spindles. When these parts are arrested the rock-shaft n is turned in the opposite direction, and carries 
 with it the cam-plates, ratchet-wheels, and spur-wheel by the pressure of the brake, and of necessity 
 reverses the motion of the rack and spindles to uncoil the threads from the spindles. At the end ol 
 this motion the catch v of the cam-plate is liberated from the ratchet-wheel H 2 , by a spur x, of a lever 
 y, jointed at 14, by the arm F 3 , of the rock-shaft n, the spur being forced on to the back end of the 
 catch by the rotation of the rock-shaft ; the lever y having a slot in it which turns and slides on a per- 
 manent rod z. This reversed motion of the rock-shaft n is effected by a crank motion in the following 
 manner, viz. : The pinion D, on the second fast pulley A, commences motion by the train of wheels B, 
 C, and R 2 , to the wheel Q 2 , in the direction of the arrow, and this wheel carries a crank-pin h', that 
 works in a slot /t 2 , of a connecting-rod O 2 , jointed to a curved arm K 2 , that vibrates on a fixed stud-pin 
 15, and this arm has a slot in it which works a slide e', for the purpose of graduating the backing-off 
 motion and to this slide is jointed another connecting-rod J 2 , the other end of which is jointed to the 
 
 arm I 2 , of the rock-shaft n. At the time that the driving-belt is shifted to the second fast pulley A', 
 which takes place whilst the momentum of the spindle prepares the parts for the backing-off motion, 
 the crank-pin h' is at h 3 , a little above a line passing from the centre of the wheel to the junction oi 
 the connecting-rod O 2 , and the arm K 2 , so that the crank-pin in this wheel can move around to the posi- 
 tion represented in Fig. 2957 before it begins to draw the connecting-rod to give time for completing 
 the preparation of the parts for backing-off. In rotating from h to 7t 4 , the crank-pin carries the connect- 
 ing-rod the required distance to give the required backing-off motion to the spindles to uncoil the thread, 
 and at the same time depresses the faller to guide the threads to the cops preparatory to winding on 
 by means of the coping-rail or former G 2 , one end of which is connected by a slot with a wrist q , on an 
 arm F 2 , of the rock-shaft n, the elevation of which, by the backing-off motion of the rock-shaft n , depresses 
 the faller. So soon as the connecting-rod O 2 has been carried to the point h 4 by the crank-pin, which 
 is the extent of the backing-off motion, the catch-lever U 2 takes hold of the pin 13, on the arm K s , and 
 there holds all the parts of the backing-off operation until released towards the end of the running mo- 
 tion of the carriage, the liberation of the parts' neing then effected by means of a pin V on the arm L, 
 on the shaft K, of the wheel F, which runs in a carriage. So long as the backing-off apparatus is held 
 
438 
 
 MULE, SELF-ACTING. 
 
 by the catch-lever U 2 , the crank-pin h' can revolve freely, the slot in the connecting-rod O 2 admitting 
 of this. When the backing-off apparatus is liberated it falls back to the position indicated in the draw- 
 ings by the weight of the coping-rail and the other parts attached to the rock-shaft ; and to prevent ja! 
 this return motion of the parts is eased off by the connecting-rod O 2 coming against the crank-pin h, at 
 the point /t 3 , the power required to turn this train of wheels in the reverse direction being sufficient tc 
 ease off and gradually arrest the moving parts without jar. This return motion of the backing-off ap- 
 paratus at the same time arrests the second fast pulley A, and the train of wheels in connection with it 
 by means of a brake,/', connected by the arm T 2 , and link S 2 , with the arm K 2 , of the backiDg-off ap- 
 paratus, and the train of wheels and the connection of the brake are so regulated as to stop the crank 
 pin h' at the point /t 3 , where it is required to be when the second series of motions is commenced. The 
 link S 2 , and the connecting-rod J 2 , are provided with adjusting-screws for the proper adjustment of all 
 these parts. As the backing-off motion must be gradually decreased as the cop is formed and increased 
 in length, the vibrating motion of the rock-shaft is gradually shortened by means of the slide e, in the 
 arm K 2 , to which the connecting-rod J 2 is jointed. For this purpose the slide is attached to a chain d, 
 which passes over the upper end of the arm, and is gradually wound up on the arbor e ", of a cog-wheel 
 L 2 , that geers into a pinion L', of a ratchet-wheel N 2 , which receives motion from the arm K 2 , of the 
 backing-off apparatus by a hand or catch M 2 , jointed thereto at z. It will be evident that as the slide 
 is drawn up by the chain towards the axis of motion of the arm K 2 , the motion of the connecting-rod J 2 
 will be diminished, and with it the motion of the backing-off apparatus. This completes the second 
 series of motions, and the mule is then in a condition to commence the third series. 
 
 When the clutch D 2 , at the end of the 
 backing-off motion, clutches the pinion E', 
 it begins to turn, which communicates mo- 
 tion to the cog-wheel F on the shaft K, or 
 to the periphery of this wheel at G is jointed 
 a connecting-rod at H ; the other end of 
 which at I is jointed to a horizontal sliding- 
 rack Y, that runs on ways W that carries 
 by means of the pinion U the train of wheels 
 that communicate motion to the carriage. 
 
 The wheel F is carried but part of a revo- 
 lution (nearly one-half) in one direction by 
 its connection with the second driving-pul- 
 ley A when the clutch D 2 is closed, which 
 gives by the crank motion, in consequence 
 of the connection above pointed out, the 
 peculiar running-in motion to the carriage, 
 as pointed out in the description of the gen- 
 eral characteristics of this invention ; and as 
 the carriage approaches the end of its run- 
 ning-in motion, the pinion E is unclutched 
 by the reversed action of the shipper-lever 
 C 3 ; this reversed motion of the shipper and 
 its appendages being effected by the pin e 
 on the arm L of the shaft K of the wheel F', 
 this pin e being on the side of the shaft K 
 opposite to the pin a which first ships it. 
 
 The unclutching the pinion E leaves the 
 wheel F free to be turned back by the re- 
 versed motion of the rack Y by the train 
 of wheels which runs out the carriage in the 
 first series of motions. 
 
 As the carriage is run in by the means 
 just described, the spindles must be turned 
 to wind up the threads which have been 
 spun during the first series of motions, and this is effected by means of the top sliding-rack W, 
 by which the backing-off motion is given, and which is placed on top of the main rack V ; the 
 connection of this rack W with the spindles by means of the friction-clutch having been described, 
 it is only necessary to the manner in w'hich the winding-on motion is communicated to it by the main 
 rack V, and the manner in which this motion is varied and regulated to correspond with the varying 
 size of the cops as they are formed. To the upper rack W, and near one end of it, is jointed a lever 
 m, to the short arm of which is attached a chain l', which thence passes around a pulley k that turns on 
 a stud-pin projecting from the side of the main rack V, the other end of the said chain being attached 
 to the smallest diameter of a scroll-cam n' connected with the end of the main rack V. From this 
 arrangement it will be obvious that if the cam n be prevented from turning on its axis, the motion of 
 the main rack V ■will carry the top rack in the same direction, and with the same varying velocity, 
 which would give to the spindles a winding-on motion, corresponding to the running-in motion of the 
 carriage, such as would be required if the cops were to be formed cylindrical and did not vary in diam- 
 eter ; but such is not the case, as clearly pointed out in the general description. To give the varying 
 motions required, and fully pointed out above, the scroll-cam n' is attached to and turns with a wheel v 
 on the stud-pin I on the main rack Y, and to this wheel at vi is attached a chain x' , which, after passing 
 around a portion of the circumference thereof is attached by a link y' to a slide z" that travels on a 
 ■crew a" that turns in the arm V 2 of a rock-frame V s , the lower end of the said arm being jointed tc 
 
MULE, SELF-ACTING. 
 
 439 
 
 another arm of equal length W 2 that vibrates on the stud-pin I', on which turn the wheel v' and the 
 oam re, so that when the slide z" is at the lower end of the arm V 2 , the end of the chain x\ which is 
 attached to the slide during the movements of the main rack, will not communicate motion to the 
 wheel v and cam re, hence the motions of the two racks Y and W will correspond and give to the 
 spindles the motion required for winding the threads on the naked spindles, and as the base of the cope 
 is increased in diameter, the slide z" is drawn up towards the axis of motion of the arm V 2 to decrease 
 the motion of that end of the chain x attached to it, which will cause the wheel and cam to turn on 
 then- axis, and thus give out the chain l', thereby giving to the top rack W', and consequently to the 
 spindles, a gradually reduced motion relatively to the main rack to correspond with the increased diam- 
 eter of the base of the cops. The motion required is given to the slide 2 " by the vibrations of the rock- 
 frame V 3 , the screw a" that operates the slide being connected by a train of cog-wheels b" e" z" h" i"j" 
 with a horizontal ratchet-wheel l" which turns freely by the rocking motion of the frame V s in one 
 direction, and which therefore does not turn the screw, but which is prevented from turning in the 
 opposite direction, during the running motion of the carriage, by a catch or pawl r" to turn the said 
 screw. Whenever the tension of the threads in winding on is too great it bears down the counter-faller, 
 (not represented in the drawings,) the arm of which in motion of the carriage strikes an arm S" of what 
 is termed a butterfly, that turns on a stud-pin q", on which the catch or hand r" of the ratchet-wheel / 2 
 also turns, and with which it is connected by a spring «> 2 , Fig. 2956, and throws it into the teeth of the 
 ratchet-wheel ; the ■wheel being thus held, the further vibration of the rock-frame turns the screw and 
 carries up the slide to reduce the motion of the spindle, and on the return motion of the carriage the 
 hand or catch r" is thrown out of the teeth of the ratchet-wheel by the arm of the counter-faller, which 
 then comes in contact with another arm f of the butterfly, the end of which extends lower down than 
 the arm S 2 , and low enough to be struck by the arm of the counter-faller when it is not under the action 
 of the tension of the threads. The catch or hand then remains out until the tension of the threads 
 again requires the motion of the spindles to be reduced. The butterfly is connected with a hand-latch 
 lever ?re 2 that turns on a stud-pin re 2 , by which the attendant can throw the butterfly in and out of play. 
 So soon as the base of the cops have been formed the scroll form of the cam re' gives the regular vary- 
 ing motions to the spindles to wind the cone of the cops, as fully pointed out in the general description. 
 
 It has been stated that in finishing the cops the threads are wound on harder at the point of the cops ; 
 this is effected in the following manner : On the shaft e” which regulates the backing-off motion, as de- 
 scribed above, there is a hub q' from which projects a crank-arm t’, to the pin S' of which is jointed, by 
 a link r', a chain p', the other end of which is jointed by a link O' to a long arm of the lever m, which 
 forms the connection between the top rack W and the chain l', which forms the connection between the 
 top and the main racks. This shaft, as heretofore described, is connected with the ratchet-w'heel N ! , 
 which is operated by the catch or hands M 2 of the lever K 2 of the backing-off apparatus, and the chain 
 p ' is of such length that it is wound up by the rotation of the shaft until towards the completion of the 
 cops, at which time it is drawn sufficiently tight to strike against a permanent arm u' towards the end 
 of the winding-on motion, which causes the lever m' to turn on its axis, and by its connection to draw 
 up the chain l, and hence to increase the velocity of the rack W, and therefore the rotation of the 
 spindles, which winds the threads on tighter. This operation gradually increases to the completion 
 of the cops. 
 
 On this same shaft e" is placed the coping-cam Y 2 , the periphery of which acts on the lever X 2 , to 
 which the coping-rail or former G 2 is jointed at r', in a manner well known to those who are acquainted 
 with the construction of self-acting mules, and which therefore needs not to be described. This com- 
 pletes the whole series of motions ; but it will be obvious that when one set of cops have been completed 
 the parts employed in giving the progressive movements, such as the shaft e'j that rotates the coping or 
 forming-cam Y 2 , winds the chain which carries the slide c' of the backing-off apparatus, and the arm t' 
 that winds the chain p' to increase the tension of the threads in finishing the points of the cop, and also 
 the ratchet-wheel P which governs the motion of the slide z" on the arm V 2 , by which the winding-on 
 motion of the spindles is regulated to form the base of the cops, are to be turned back by hand to their 
 original position by the attendant, preparatory to commencing a new set of cops. 
 
 I have thus described the general plan of my invention, and the manner of constructing and using the 
 same; but before pointing out what I claim as my invention, I wish it to be distinctly understood that 
 I do not limit myself to the precise form and construction of the various parts employed, or to the 
 precise arrangement described, as I consider all mechanical equivalents as within the limits of my 
 invention. What I claim, therefore, as my invention, and desire to secure by Letters Patent, is, 
 1st. The disconnecting of the mechanism employed in running out the carriage and turning the draw- 
 rollers from the mechanism which gives the whirling or spinning motion to the spindles when the 
 driving-power is shifted from these the first series of motions to enable the spindles to continue their 
 motion by inertia, independent of the other motions, by means of the clutch-box or its equivalent, which 
 forms the connection between the three movements, constituting the first series of motions whereby (he 
 momentum of the spindles can be employed for preparing the parts for the backing-off motion, substan 
 tially as described. 2d. The method of preparing the parts for the backing-off motion by means of the 
 momentum of the spindles, by connecting them with the backing-off apparatus by means of the friction 
 clutch or any equivalent therefor, substantially as described. 8d. The backing-off apparatus, consisting 
 of the combination of the top sliding-rack, which communicates motion to the spindles ; the rocking is 
 with a cam and spring-brake, and other appendages, and the connecting-rod operated by the crank, al‘ 
 substantially as described. 4th. The method of decreasing the backing-off motion to correspond with 
 the increased length of the cops, by means of the slide in the intermediate arm of the connecting-rod, 
 (between the two sections of the connecting-rod,) by means of which the rocking motion of the rock- 
 shaft is gradually decreased, substantially as described, to avoid any sudden strain or jar upon the 
 threads. 5th. The method of communicating the winding-on motion to the spindles from the main rack, 
 which runs in the carriage by combining the said main rack with the top sliding-rack, by means of a 
 
440 
 
 NAIL-MACHINE. 
 
 chain and scroll-cam, or their equivalents ; by means of which combination, in connection with the fora: 
 of the cam, the motions of the spindles so correspond with that of the carriage as to wind the threads 
 on the conical form of the cops, as described. 6th. The method of varying the winding-on motion of 
 the spindles to form the base of the cops, by means of the slide and chain which vary the motions of 
 the wheel that is attached to and which rotates the scroll-cam, substantially as described, whether the 
 slide be operated by the vibration of the arm on which it slides, or by any other means substantially 
 as herein described. 7th. The method of regulating the motion of the slide that varies the motion of 
 the scroll -cam of the winding-on motion, by means of what is termed the butterfly and its appendages, 
 when this is acted upon by the counter-faller, operated by the tension of the threads, substantially as 
 described. And 8th. The method of winding on the threads tighter at the points of tire cops when 
 finishing them, by means of tire apparatus which gives to the top sliding-rack an increased motion 
 towards the end of the operation ; the said apparatus consisting of a chain, which is connected with a 
 chain that forms the connection betwen the main and top racks, and which is gradually wound up and 
 strikes against an arm towards the end of the operations of the mule to shorten the connection between 
 the two racks, and thus increase the winding-on motion of the spindles, as described. 
 
 NAIL-MACHINE. The manufacture of cut nails is entirely an American invention, and was born 
 
 <L 
 
 A 
 
 in our country, and has advanced, 
 within its bosom, through all the 
 various stages of infancy to man- 
 hood ; and no doubtwe shall soon 
 be able, by receiving proper en- 
 couragement, to render them su- 
 perior to wrought nails in every 
 particular. 
 
 The nail-machine now exten- 
 sively in use in this country for 
 all sizes of cut-nails is exhibited 
 in the following figures, and is 
 the machine in operation at Z. B. 
 
 Crooker's Nail Works, in Brook- 
 lyn, L. I. 
 
 Fig. 2965 represents the front 
 elevation of the machine. 
 
 Figs. 2966 and 2967 side ele- 
 vations. 
 
 Fig. 2968 side and end eleva- 
 tions, showing the method of 
 turning the nail-plate. 
 
 Fig. 2969 a general plan of 
 the machine. 
 
 a a, frame of the machine ; b, 
 main-shaft for carrying the cams, 
 driven by a belt over the pul- 
 ley e, and provided with a fly- 
 wheel d ; c, guide which consists 
 of a metal tube through which passes the nail-rod, holding by means of pincers the nail-plate A, Fig 
 i967. and enlarged view A, Fig. 2968. 
 
 
 
 1 
 
 
 . / 
 
 1 
 
 Stt81III8 
 
NAIL-MACHINE. 
 
 441 
 
 In order to give the wedge-shape required in the brad or cut-nail, the cutter is set oblique to the 
 direction of the nail-plate, which is reversed after each cut, by which means each and every nail has a 
 uniform taper. The reversing of the nail-plate is effected by means of a rocking-shaft r which receives 
 its motion from the shaft through a geering/, and crank producing an alternating motion to the seg- 
 ments v Fi°-s °967 and 2968, which is communicated to the guide-tube c, by a belt and pulley, the nail- 
 plate being fed to the cutter by means of a weight m, as shown in Figs. 2967 and 2968, the nail-rod 
 with its attached plate vibrating freely within the guide-tube c. 
 
 The cutter, having the width of a 
 nail-plate, is adjusted by screws to 
 the cutting-block p ; the nail-plate A, 
 lying between guides, rests on the iron 
 block k, and bearing by the action of 
 the weight m against the face of the 
 cutter. The vibratory movement of 
 the latter is effected by means of the 
 crooked lever /, worked by an eccen- 
 tric on the main-shaft — the cutter- 
 block p, forming the short arm of this 
 lever, has a short circular movement 
 about their common centre. The le- 
 ver b, cutter-block p, and the axle 
 arms or trunnions upon which they 
 work being all cast in one piece, are 
 shown in Figs. 2965, 2966, 2967, 2969. 
 
 y, Fig. 2965, shows the lever of the 
 heading-die, which is worked by a 
 crank-pin and rod i, attached to a 
 wheel q , on the main-shaft. 
 
 To prevent the nail falling from its 
 place before the completion of the 
 
 stroke, a small pair of nippers, operated by means of a cam t on the main-shaft, are placed below and 
 in front of the cutter-block ; these are worked by the rods z. 
 
 The working of the machine is as follows : 
 
 The nail-plate rests against the frame of the cutter, the lever l resting on the point of the cam or ec- 
 centric ; as the latter revolves, the lever l falls, lifting the edge of the cutter above the cutting-block, 
 and also above the nail-plate ; the latter, by the action of the weight m, is thrown forward under the 
 cutter to a stop the width of the required nail ; at this point, by the revolution of the eccentric, the lever 
 l is raised, which lowers the edge of the cutter, shearing off a wedge-shaped strip of metal, having the 
 length of the width of the nail-plate ; this is seized at the same instant by the nippers below the cutter, 
 and immediately after the rod i, by the action of its crank, raises the lever y, of the heading-die, and 
 the nail is completed at a stroke. As the complete nail drops from the opening nippers the nail-plate 
 is advanced under the cutting-shears for another naiL 
 
 The action of this machine is very perfect, and is suited for all dimensions of cut-nails ; the machine 
 of course being heavier and larger to suit the different sizes. See Spikes. 
 
 NEEDLES. The making of needles, although largely carried on at Birmingham and a few other 
 towns, is mainly conducted at Redditch in Worcestershire. We should surprise many a reader were 
 we to enumerate all the processes incident to the manufacture of a needle, giving to each the teclmi- 
 cal name applied to it in the factory. The number would amount to somewhere about thirty ; but it 
 will be more in accordance with our object to dispense with such an enumeration, and to present the 
 details of manufacture in certain groups, without adhering to a strictly technical arrangement. 
 
 First, then, for the material. It is scarcely necessary to say that needles are made of steel, and that 
 
442 
 
 NEEDLES. 
 
 tlie steel is brought into the state of fine wire before it can assume the form of needles. The needle- 
 makers are not wire-drawers : they do not prepare their own wire, but purchase it, in sizes varying with 
 the kind of needles which they are about to make, from Sheffield or Birmingham, or some similar town. 
 We will suppose, therefore, that the wire is brought to the needle factory, and is deposited in a store- 
 room. This room is kept warmed by hot air to an equable temperature, in order that the steel may 
 be preserved free from damp or other sources of injury. Around the walls are wooden bars or racks, 
 on which are hung the hoops of wire. Each hoop contains, on an average, about twelve or fourteen 
 pounds of wire, the length varying according to the diameter. Perhaps it may be convenient to take 
 some particular size of needle, and make it our standard of comparison during the details of the pro- 
 cess. The usual sizes of sewing needles are from No. 1, of which twenty -two thicknesses make an 
 inch, to No. 12, of which there are a hundred to an inch. Supposing that the manufacturer is about 
 to make sewing needles of that size which is known to sempstresses as No. 0 — then the coil of wire is 
 about two feet in diameter ; it weighs about thirteen pounds ; the length of wire is about a mile and 
 a quarter ; and it will produce forty or fifty thousand needles. The manufacturer has a gage, con- 
 sisting of a small piece of steel, perforated at the edge with eighteen or twenty small slits, all of 
 
 different sizes, and each having a particular number attached to it. By this gage the diameter of 
 
 every coil of wire is tested, and by the number every diameter of wire is known. 
 
 A coil of wire, when about to be operated on, is carried to the cutting-shop, where it is cut into 
 pieces equal to the length of two of the needles about to be made. Fixed up against the wall 
 of the shop is a ponderous pair of shears with the blades uppermost. The workman takes probably 
 a hundred wires at once, grasps them between his hands, rests them against a gage to determine 
 the length to which they are to be cut, places them between the blades of the shears, and cuts 
 them by pressing with his body or thigh against one of the handles of the shears. The coil is thus 
 reduced to twenty or thirty thousand pieces, each about three inches long ; and as each piece had form- 
 ed a portion of a curve two feet in diameter, it is easy to see that it must necessarily deviate somewhat 
 from the straight line. This straightness must be rigorously given to the wire before the needle-making 
 is commenced ; and the mode by wliich it is effected is one of the most remarkable in the whole manu- 
 facture. In the first place, the wires are annealed. There are provided a number of iron rings, each 
 from three or four to six or seven inches in diameter, and a quarter or half an inch in thickness. Two 
 of these rings are placed upright on their edges, at a little distance apart ; and within them are placed 
 many thousands of wires, which are kept in a group by resting on the interior edges of the two rings. 
 In this state they are placed on a shelf in a small furnace, and there kept till red-hot. On being 
 taken out, at a glowing heat, they are placed on an iron plate, the wires being horizontal, and the 
 rings in which they are inserted being vertical. The process of “rubbing” (the technical name for the 
 straightening to which we allude) then commences. The workman takes a long piece of iron or steel, 
 perhaps an inch in width, and, inserting it between the two rings, rubs the needles backwards and 
 forwards, causing each needle to roll over its own axis, and also over and under those by which it is 
 surrounded. The noise emitted by this process is just that of filing : but no filing takes place ; for the 
 rubber is smooth, and the sound arises from the rolling of one wire against another. The rationale of 
 the process is this: — the action of one wire on another brings them all to a perfectly straight form, 
 because any convexity or curvature in one wire would be pressed out by the close contact of the 
 adjoining ones. 
 
 Our needles have now assumed the form of perfectly straight pieces of wire, say a little more than 
 three inches in length, blunt at both ends, and dulled at the surface by exposure to the fire. Each of 
 these pieces is to make two needles, the two ends constituting the points ; and both points are made 
 before the piece of wire is divided into two. The pointing immediately succeeds the rubbing, and 
 consists in grinding down each end of the wire till it is perfectly sharp. This is the part of needle 
 making which has attracted more attention than all the rest put together. The surprising manipula- 
 tion by which the needles are applied to the grindstone ; the rapidity with which the grinding is 
 effected ; the large earnings of the men ; the ruined health and early death which the occupation 
 brings upon them ; the efforts which have been made to diminish the hurtfulness of the process ; and 
 the resistance with which these efforts have been met — all merit and have received a large measure 
 of attention. Let us first notice the process itself, and then the peculiar circumstances attending it. 
 
 Some of the needle-pointers work at their own homes, while some work at the factories ; but the 
 process is the same in either case. The pointing-room, generally situated as far away as practicable 
 from the other rooms, contains small grindstones, from about eight inches to twenty inches in diam- 
 eter, according to the size of needle to be pointed. They rotate vertically, at a height of about two 
 feet from the ground, and with a velocity frequently amounting to two thousand revolutions per 
 minute. The stone is a particular kind of grit adapted for the purpose ; but sometimes it flies in 
 pieces, from the centrifugal force engendered by the rapid rotation, and in such cases the results are 
 often fearful. The workman sits on a stool, or horse, a few inches distant from the stone, and bends 
 over it during his work. Over his mouth he wraps a large handkerchief, and, as he can perform his 
 work nearly as well in the dark as in the light, he is sometimes only to be seen by the vivid cone of 
 sparks emanating from the steel while grinding. The vivid light reflected on his pale face, coupled 
 with the consciousness that we are looking at one who will be an old man at thirty, and who is being 
 literally “killed by inches” while at work, renders the processes conducted in this room such as will 
 not soon be forgotten. 
 
 The needle-pointer takes fifty or a hundred needles, or rather needle wires, in his hand at once, and 
 holds them in a peculiar manner. He places the fingers and palm of one hand diagonally over those 
 of the other, and grasps the needles between them, all the needles being parallel. The thumb of the 
 left hand comes over the back of the fingers of the right, and the different knuckles and joints are so 
 arranged that every needle can be made to rotate on its own axis by a slight movement of the hand, 
 without any one needle being allowed to roll over the others. He grasps them so that the ends of the 
 
NEEDLES. 
 
 443 
 
 wire (one end of eacli) project a small distance beyond the edge of the hand and fingers, and these 
 ends he applies to the grindstone in the proper position for grinding them down to a point. It will 
 easily be seen that if the wires were held fixedly the ends would merely be bevelled off, in the man- 
 ner of a graver, and -would not give a symmetrical point ; but by causing each wire to rotate while 
 actually in contact with the grindstone, the pointer works equally on all sides of the wire, and brings 
 the point in the axis of the wire. At intervals of every few seconds he adjusts the needles to a proper 
 position, against a stone or plate, and dips their ends in a little trough of liquid between him and the 
 grindstone. Each wire sends out its own stream of sparks, which ascends diagonally in a direction 
 opposite to that at which the workman is placed. So rapid are his movements that he will point 
 seventy or a hundred needles, forming one hand-grasp, in half a minute — thus getting through ten 
 thousand in an hour ! 
 
 The circumstance which renders this operation so very destructive to health is, that the particles of 
 steel, separated from the body of the wire by the friction of the stone, float in the air for a time, and 
 are then inhaled by the workman ; and the same remarks apply to this destructive occupation as to 
 fork-grinding. 
 
 The reader will bear in mind that the state of our embryo needle is simply that of a piece of dull 
 straight wire, about three inches long, (supposing 6’s to be the size,) and pointed at both ends. The 
 next process is one of a series by which two eyes or holes are pierced through the wire, near the centre 
 of its length, to form the eyes of the two needles which are to be fashioned from the piece of wire. 
 A number of very curious operations are connected with this process, involving mechanical and manip- 
 ulative arrangements of great nicety. Those who are learned in the qualities of needles — as that they 
 will not “ cut in the eye,” (fee. — will be prepared to expect that much delicate workmanship is involved 
 m the production of the eyes, and they will not be in error in so supposing. Most of the improvements 
 which have from time to time been introduced in needle-making relate more or less to the production 
 of the eve. In the commoner kinds of needles many processes are omitted which are essential to the 
 production of the finer qualities, but it will show the whole nature of the operations better for us to 
 take the case of those which involve all the various processes. 
 
 After being examined when the pointer has done his portion of the work to them, (an examination 
 wliicli is undergone after every single process throughout the manufacture,) the wires are taken to the 
 stamping-shop, where the first germ of an eye is given to each half of every wire. The stamping- 
 machine consists of a heavy block of stone, supporting on its upper surface a bed of iron ; and on this 
 bed is placed the under half of a die or stamp. Above this is suspended a hammer, weighing about 
 thirty pounds, which has on its lower surface the other half of the die or impress. The hammer is 
 governed by a lever moved by the foot, so that it can be brought down exactly upon the iron bed. 
 The form of the die or stamp may be best explained by stating the work which it is to perform. It is 
 to produce the gutter, or channel, in which the eye of a needle is situated, and which is to guide the 
 thread in the process of “ threading a needle.” 
 
 But besides the two channels or gutters, the stampers make a perforation partly through the needle, 
 as a means of marking exactly where the eye is to be. The device on the two halves of the die is 
 consequently a raised one, since it is to produce depressions in the wire. The workman, holding in his 
 hand several wires, drops one at a time on the bed-iron of the machine, adjusts it to the die, brings 
 down the upper die upon it by the action of the foot, and allows it to fall into a little dish when done. 
 This he does with such rapidity that one stamper can stamp four thousand wires, equivalent to eight 
 thousand needles, in an hour, although he has to adjust each needle separately to the die. 
 
 To tins process succeeds another, in which the eye of the needle is pierced through. This is effected 
 by boys, each of whom works at a small hand-press, and the operation is at once a minute and inge- 
 nious one. The boy takes up a number of needles or wires, and spreads them out like a fan. He lays 
 them flat on a small iron bed or slab, holding one end of each wire in his left hand, and bringing the 
 middle of the wire to the middle of the press. To the upper arm of the press are affixed two hard- 
 ened steel points or cutters, being in size and shape exactly corresponding with the eyes which they 
 are to form. Both of these points are to pass through each wire, very nearly together, and at a small 
 distance on each side of the exact centre of the wire. The wire being placed beneath the points, the 
 press is moved by hand, the points descend, and two little bits of steel are cut out of the wire, thereby 
 forming the eyes for two needles. As each wire becomes thus pierced, the boy shifts the fanlike array 
 of wires until another one comes under the piercers, and so on throughout. The press has to be worked 
 by the right hand for piercing each wire ; and the head of the boy is held down pretty closely to his 
 work, in order that he may see to eye the needles properly 1 Were not the wires previously pre- 
 pared by the stamper, it would be impossible thus to guide the piercers to the proper point ; but this 
 being effected, patience, good eyesight, and a steady hand effect the rest. 
 
 There are several processes about this stage which are effected by boys. Some of these little la 
 borers take the needles when they have been eyed, ar.d proceed to spit them ; that is, to pass a 
 wire through the eye of every needle. Two pieces of fine wire perhaps three or four inches in length, 
 are prepared, the diameter corresponding exactly with the size of the needle-eye. These two pieces 
 of wire are held in the right hand, parallel, and at a distance apart equal to the distance between the 
 two eyes in each needle wire. The pierced needles, being held in the left hand, are successively 
 threaded upon the two pieces of smaller wire, till, by the time the whole is filled, the assemblage has 
 something the appearance of a fine-toothed comb, as shown in Fig. 2910. A workman then files down 
 the bur or protuberances left on the side of the eye by the stamping. 
 
 It must be borne in mind that throughout all these operations the needles are double ; that is, that 
 the piece of wire, three inches in length, which is to produce two needles an inch and a half long each, 
 is still whole and undivided, the two eyes being nearly close together in the centre, and the two 
 points being at the ends. Now, however, the separation is to take place. The filer, after he has 
 brought down the protuberances on each wire, but before he has laid the comb of wires out of his hand. 
 
444 
 
 NEEDLES. 
 
 bends and works the comb between his hands in a peculiar way, until he has broken the comb inti 
 two halves, each half spitted by one of the fine wires. The needles have arrived at something like thei* 
 destined shape and size: for they are of the proper length, and have eyes and points. In Fig. 2971 
 we can trace the wire through the processes of change hitherto undergone. 
 
 2971. 
 
 In Fig. 2971, A is the wire for two needles; B the same, pointed at one end ; C pointed at both 
 ends ; D the stamped impress for the eyes ; E the eyes pierced ; F the needles just before separation • 
 def Fig. 2972, enlargements of D E F. 
 
 But although we have now little bits of steel, which might by courtesy be called needles, they have 
 very many processes to undergo before they are deemed finished, especially if, in accordance with our 
 previous supposition, they are of the finer quality. There are very many workshops which we have yet 
 to glance through, the first of which is that of the soft-straightener. The filer and his two spitters (who 
 together get ready about four thousand needles in an hour) are very likely to bend in a slight degree 
 the needles under operation ; and, indeed, so are likewise the stampers and the eye-makers. To re- 
 store the straightness of the wire is the office of the soft-straightener, who is frequently a female. 
 
 The soft-straightener is seated in front of a bench, near the front edge of which is placed a small 
 steel plate. On this plate the needles are placed, parallel or nearly so; the straightener employed is 
 a steel bar, from a foot to half a yard long, an inch or two in width, and perhaps a quarter of an inch 
 thick. It is turned upwards a little at the two ends, so as to be somewhat convex at the lower sur- 
 face, and is held by both hands at the two ends. By a curious management of this instrument, the 
 6oft-straightener separates each individual needle from the group of which it forms a part, and rolls 
 it over two or three times with the lower surface of the instrument, pressing it against the iron plate, 
 and thus working out any curvatures or irregularities which may have been given to it by the previous 
 operations. So quickly is this done that three thousand needles can be thus straightened in an hour by 
 one person. 
 
 The needles are by this time pointed, eyed, and straightened ; but before they can be brought to that 
 beautifully finished state with which we are all familiar, it is necessary that they should be hardened 
 and tempered by a peculiar application of heat. After being examined, to see that the preceding pro- 
 cesses are fitly performed, the needles are taken to a shop provided with ovens or furnaces. They are 
 laid down on a bench, and by means of two trowel-like instruments, spread in regular thick layers on 
 narrow plates or trays of iron. In this way they are placed on a shelf or grating in a heated furnace 
 When the proper degree of heating has been effected, the door is opened, and the needles are shifted 
 from the iron tray into a sort of colander or perforated vessel immersed in cold water or oil. When 
 they are quite cooled, the hardening is completed ; and if it has been effected in water, the needles are 
 simply dried ; but if in oil, they are well washed in an alkaline liquor to free them from the oil. Then 
 ensues the tempering processes. The needles are placed on an iron plate, heated from beneath, and 
 moved about with two little trowels until every needle has been gradually brought to a certain desired 
 temperature. 
 
 Notwithstanding the soft-straightening which the needles underwent after they were pointed and 
 eyed, they have become slightly distorted in shape by the action of the heat in the processes just de- 
 scribed, and to rectify this they undergo the operation of hammer-straightening. A number of female* 
 are seen seated at a long bench, each with a tiny hammer, giving a number of light blows to th"' •' c “» 
 
NEEDLES. 
 
 445 
 
 dies ; the needles being placed on a small steel block with a very smooth upper surface. This is rathei 
 a tedious part of the manufacture, the workwoman not being able to straighten more than live hundred 
 needles in an hour, a degree of quickness much less than that which we have had hitherto to notice. 
 
 We leave the tinkling hammers, and follow the needles to the only part of the manufacture which in- 
 volves apparatus other than of a very small size. This is the scouring process, performed by machines, 
 looking like mangles, or, perhaps more correctly, like marble polishing-machines — a square slab or rub- 
 ber working to and fro on a long bed, stone, or bench. The object of this process is to rub the needles 
 one against another for a very long period, till the surfaces of all have become perfectly smooth, clean, 
 and true. This is effected in a curious manner. A strip of very thick canvas is laid out open on a 
 bench, and on this a large heap of needles, amounting to perhaps twenty or thirty thousand, is laid, all 
 the needles being parallel one with another, and with the length of the cloth. The needles are then 
 slightly coated with a mixture of emery and oil, and tied up tightly in the canvas, the whole forming a 
 compact roll about two feet long and two inches in thickness. Twenty-four rolls of needles being thus 
 prepared, comprising probably six hundred thousand needles in all, they are placed under the rubbers 
 of the scouring-machines, tv T o rolls to each machine. A steam-engine or a water-wheel then gives to 
 the rubbers, by connected mechanism, a reciprocating or backward and forward motion, pressing heavily 
 on the rolls of needles, and causing all the needles of each bundle to roll one over another. By this 
 action an intense degree of friction is exerted among the needles, whereby each one is rubbed smooth 
 by those which surround it. For eight hours uninterruptedly this rubbing or scouring is carried on ; 
 after which the needles are taken out, washed in suds, placed in new pieces of canvas, touched with a 
 new portion of emery and oil, and subjected to another eight hours’ friction. Again and again is this 
 repeated, insomuch that for the very finest needles the process is performed five or six times over, each 
 time during eight hours’ continuance. 
 
 The needles are examined after being scoured, and are placed in a small tin tray, wdiere, by shaking 
 and vibrating in a curious manner, they are all brought into parallel arrangement. From thence they 
 are removed into flat paper trays, in long rows or heaps, and passed on to the “ header,” generally a 
 little girl, whose office is to turn all the heads one way and all the points the other. This is one among 
 the many simple but curious processes involved in this very curious manufacture, which surprise us by 
 the rapidity and neatness of execution. The girl sits with her face towards the window, and has the 
 needles ranged in a row or layer before her, the needles being parallel with the window. She draws 
 out laterally to the right those which have their eyes on the right hand, into one heap ; and to the left 
 those which have their eyes in that direction, in another. 
 
 About this time too the needles are examined one by one, to remove those which have been broken 
 or injured in the long process of scouring ; for it sometimes happens that as many as eight or ten thou- 
 sand out of fifty thousand are spoiled during this operation. Most ladies are conversant with the merits 
 of “ drilled-eyed needles,” warranted “not to cut the thread.” These are produced by a modern improve- 
 ment, whereby the eye, produced by the stamping and piercing processes before described, is drilled 
 with a very fine instrument, by which its margin becomes as perfectly smooth and brilliant as any other 
 part of the needle. To effect this the needle is first “ blued,” that is, the head is heated so as to give it 
 the proper temper for working. Then the eye is counter-sunk, which consists in bevelling off the eye 
 by means of a kind of triangular drill, so that there may be no sharp edge between the eye itself and 
 the cylindrical shaft of the needle. Next comes the drilling. Seated at a long bench are a number of 
 men and boys, with small drills working horizontally with great rapidity. The workman takes up a 
 few needles between the finger and thumb of his left hand, spreads them out like a fan with the eyes 
 uppermost, brings them one at a time opposite the point of the drill, governs the handle or lever of the 
 drill with his right hand, and drills the eye, which is equivalent to making it circular, even, smooth, and 
 polished. lie shifts the thumb and finger round, so as to bring all the needles in succession under the 
 action of the drill ; and he thus gets through his work with much rapidity. The preparation of the 
 drills, which are small wires of polished steel three or four inches long, is a matter of very great nicety, 
 and on it depends much of that beauty of production which constitutes the pride of a modern needle- 
 manufacturer. 
 
 The needles are next applied to the edges of little wheels revolving with great rapidity, some in 
 tended for what is termed “grinding” the needles, and some for polishing. The men are seated on low 
 stools, each in front of a revolving wheel, which is at a height of perhaps two feet from the ground 
 The grinding-wheels are very small, not above five or six inches in diameter ; they are made of grit 
 stone, and are attached to a horizontal axis. The grinding here alluded to is not such as might be sup 
 posed, relating to the points of the needles, but has reference simply to the heads, which have not yet 
 had a rounded form given to them. The workman takes up a layer or row of needles between the fin 
 gers and thumbs of the two hands, and applies the heads to 
 
 the stones in such a manner as to grind down any small as- 29~3. 
 
 perities on the surface. As the small grindstones are revolving 
 three thousand times in a minute, it is plain that the steel may 
 soon be sufficiently worn away by a slight contact with the 
 periphery of the stone. 
 
 The grinders and the polishers sit near together, so that the 
 latter take up the series of operations as soon as the former 
 
 have finished. The polishing-wheels consist of wood coated I I I 
 
 with buff leather, whose surface is slightly touched with polish- 
 ing-paste. Against these wheels the polishers hold the nee- 
 dles, applying every part of the cylindrical surface in succes- 
 
 sion ; first holding them by the pointed end, and then by the | JJ 
 
 eye end. About a thousand in an hour can thus be polished 
 by each man ; and when they leave his hands the needles are finished. A magnified representation 
 
 d 
 
446 
 
 NUT-CUTTING MACHINE. 
 
 of the eye in different states will assist these details, a , Fig. 2973, represents a needle with the ev t 
 and head rough ; b, the head filed and formed ; c, the eye countersunk ; d represents a needle drilled 
 and finished. 
 
 NICKEL. A white metal, ductile, malleable, attracted by the magnet, and which, like iron, may be 
 rendered magnetic. Its specific gravity when hammered is about 9. It is rather more fusible than pure 
 iron ; is not altered by exposure to air and moisture at common temperatures, but is slowly oxidized 
 at a red heat. It is found in all meteoric iron ; but its principal ore is a copper-colored mineral found 
 in Westphalia, and called kupfernickel, nickel being a term of detraction used by the German miners, 
 who expected from the color of the ore to find that it contained copper. The salifiable oxide of nickel 
 consists of 30 nickel + 8 oxygen. Its salts are mostly of a grass-green color, and the ammoniacal solu- 
 tion of its oxide is deep blue, like that of copper. See Metals and Alloys. 
 
 NONAGON. A figure of nine angles and nine sides. The angle at the centre of a nonagon is 40°, 
 the angle subtended by its sides 140°, and its area ■when the side is 1 = GT818242, consequently the 
 square of the side X 6T818242 will give the area of the figure. 
 
 NORMAL. A term sometimes used for perpendicular. In the geometry of curve lines, the normal 
 to a curve at any point is a straight line perpendicular to the tangent at that point, and included between 
 the curve and the axis of the abscissa. 
 
 NUT-CUTTING MACHINE — By A. Milne, Glasgow. This is a very convenient tool in works 
 
 where the chief business is the construction of the more 
 finished quality of machinery. In these the nuts are usu- 
 ally dressed to correspond with the other parts of the work. 
 It is not commonly employed by millwrights, although its 
 use would often be a material saving of time in the fitting- 
 shop, and especially in out-door work, in reducing the nuts, 
 and consequently the number of keys required, to a few 
 definite sizes. 
 
 Fig. 2974 is a side elevation. Fig. 2975 an end eleva- 
 tion. Fig. 2976 a general plan of the machine. 
 
 a is the main-spindle, having a spur-wheel w, and the 
 cutter x, keyed on it. 
 
 k, the driving-shaft, carrying fast and loose pulleys, and 
 having the pinion p keyed on it, and which geers into the 
 wheel w. 
 
 r, the nut-holder : the nuts are screwed on a pin which 
 is tightened by a nut on the under side, seen in Fig. 2974, 
 by a counter-nut; different sizes of these mandrel-pins 
 or screws are of course required for different sizes of 
 nuts. 
 
 b, a hand-wheel, upon the end of a slide-lever for carry- 
 ing the nut across the end of the cutter. 
 
 c, a shaft carrying a set of grooved pulleys, connected 
 by a cord, with a corresponding set on the shaft k. 
 
 s, an endless screw on the shaft c, and working into the 
 wheel h, on the slide-screw, to render the machine self- 
 acting 
 
 2375 . 
 
OILS. 
 
 447 
 
 rn, a handle to disengage the self-acting feed when desired. The upper part of the slide on which 
 the nuts are fixed turns round, and is held in the position required by the handle n, the end of which is 
 pressed, by a spring, into notches on the rim of the table. See Fig. 297 6. 
 
 u , a screw for moving forward the head carrying the cutter, so as to adjust it to the size of nut to bo 
 cut. This operation is accomplished by hand. 
 
 OCTAGOK In geometry, a plane figure contained by eight sides, and consequently having eight 
 angles. When the sides and angles are equal, it is a regular octagon. If a denote the side of a regular 
 octagon, the area is a 3 X 2 tan. 67^° = a" X 4'828427. 
 
 OCTOHEDRON. In geometry, one of the five regular solids, or Platonic bodies, contained under 
 eight equal and equilateral triangles. Let 
 
 A = the linear edge or side, 
 
 B = the whole surface, 
 
 C = the solid content, 
 
 R = radius of circumscribed sphere, 
 r — radius of inscribed sphere ; then 
 A = r N /6 = RV2 = v /(JB v /3) = 7|C72), 
 
 B = 12 r V 3 = 4 R V3 = 2 A V3, 
 
 C =4 r V 3 = f R 3 = *- A V 2, 
 
 R = r v /3 = iA v /2=WB v /I = 7IC, 
 
 r = iR % /3=^A v /6=l v /(B v /S). 
 
 ODOMETER. An instrument attached to the wheel of a carriage, by which the distance passed 
 over is measured. 
 
 OILS. The term oil is applied to two dissimilar and distinct organic products, which are usually 
 called fixed oils and volatile oils. The fixed or fat oils are either of vegetable or animal origin ; they 
 are compounds of carbon, hydrogen, and oxygen; the relative proportions vary but little in the several 
 species. The following analyses of olive and spermaceti oil may be assumed as types of the rest : 
 
 Olive oil. Spermaceti oil. 
 
 Carbon 772 780 
 
 Hydrogen 133 118 
 
 Oxygen 95 102 
 
 1000 1000 
 
 Th q fixed oils abound in the fruit and seed of certain plants ; they are lighter than water, unctuous, 
 and insipid, or nearly so ; some of these require a low temperature for their congelation, such as linseed 
 oil ; others, such as olive oil, concrete at a temperature higher than the freezing point of water ; some 
 are solid at common temperatures, such as cocoa-nut oil. Some of these oils when exposed to air absorb 
 oxygen, and gradually harden, forming a kind of varnish ; these are called drying oils, and are the basis 
 of paints, such as linseed oil ; others become rancid, as almond oil. All these oils, like the different 
 kinds of fat, consist of two proximate principles, called stearine and elaine ; the former is the fatty por- 
 tion, which first concretes on cooling the oil, and from which the elaine, or oily portion, may be separ- 
 ated by pressure. These oils cannot be volatilized without decomposition. At a red-heat they are 
 resolved into volatile and gaseous products, among which carburetted hydrogen, in several of its forms, 
 predominates ; hence the use of these oils, when volatilized and burned by the aid of a wick, as sources 
 of artificial fight. The action of the alkali on the fat oils is highly important, as forming soap. 
 
 The volatile oils are generally obtained by distilling the vegetables which afford them with water ; 
 they fluctuate in density a little on either side of water : they are sparingly soluble in water, forming 
 the perfumed or medicated waters, such as rose and peppermint water ; they are mostly soluble in 
 alcohol, forming essences. A few of them, such as oil of turpentine, of lemon peel, of copivi balsam, &c., 
 are hydro-carbons, that is, consist of carbon and hydrogen only ; the greater number, however, contain 
 oxygen as one of their ultimate elements. They are chiefly used in medicine and in perfumery, and a 
 
448 
 
 OILS. 
 
 few of them are extensively employed in the arts as vehicles for colors, and in the manufacture of var 
 nislies ; this is especially the case with oil of turpentine. 
 
 Linseed, rape-seed, poppy-seed, and other oleiferous seeds were formerly treated for the extraction ol 
 their oil, by pounding in hard wooden mortars with pestles shod with iron, set in motion by cams driven 
 by a shaft turned with horse or water power ; then the triturated seed was put into woollen bags which 
 were wrapped up in hair-cloths, and squeezed between upright wedges in press-boxes by the impulsion 
 of vertical rams driven also by a cam mechanism. In the best mills upon the old construction, the cakes 
 obtained by this first wedge-pressure were thrown upon the bed of an edge-mill, ground anew, and sub- 
 jected to a second pressure, aided by heat now as in the first case. These mortars and press-boxes 
 constitute what are called Dutch mills. They are still in very general use, and are by many persons 
 supposed to be preferable to the hydraulic presses. 
 
 2977. 
 
 In extracting oil from seeds two processes are required — 1st , trituration ; 2d, expression ; and the 
 steps are as follows : 
 
 L Bruising under revolving heavy-edge mill-stones, in a circular bed or trough of iron, bedded on 
 granite. 
 
 2. Heating of the bruised seeds, by the heat either of a naked fire or of steam. 
 
 3. First pressure or crushing of the seeds, either by wedges, screw, or hydraulic presses. 
 
 4. Second crushing of the seed-cakes of the first pressure. 
 
 5. Heating the bruised cakes : and 6. A final crushing. 
 
 The seeds are now very generally crushed first of all between two iron cylinders revolving in opposite 
 directions, and fed in from a hopper above them ; after which they yield more completely to the tritu- 
 rating action of the edge-stones, which are usually hooped round with a massive iron ring. A pair ol 
 edge mill-stones of about V or Ti feet in diameter, and 25 or 26 inches thick, weighing from V to 8 tons, 
 can crush, in 12 hours, fro.n 2^- to 3 tons of seeds. The edge mill-stones serve not merely to grind the 
 
OILS. 
 
 449 
 
 seeds at first, but to triturate the cakes after they have been crushed in the press. Old dry seeds some- 
 times require to be sprinkled with a little water to make the oil come more freely away ; but this 
 practice requires great care. 
 
 The apparatus for heating the bruised seeds consists usually of cast-iron or copper pans, with stirrers 
 moved by machinery. Figs. 2977, 2978, 2979, and 2980 represent the heaters by naked fire, as mounted 
 in Messrs. Maudsley and Field’s seed-crushing mills, on the wedge or Dutch plan. 
 
 Fig. 2977 is an elevation or side view of the fireplace of a naked heater. 
 
 Fig. 2978 is a plan in the line U U of Fig. 2977. 
 
 Fig. 2979 is an elevation and section parallel to the line V V of Fig. 2978. 
 
 Fig. 2980 is a plan of the furnace, taken above the grate of the fireplace. 
 
 A, fireplace shut at top by the cast-iron plate B, called the fire-plate. C, iron ring-pan, resting on the 
 plate B, for holding the seeds, which is kept in its place by the pins or bolts a. D, funnels, britchen, 
 into which, by pulling the ring-case c by the handles b b, the seeds are made to fall, from which they 
 pass into bags suspended to the hooks c. 
 
 2981. 2982. 
 
 E, Fig. 2979, the stirrer which prevents the seeds from being burned by continued contact with the 
 hot plate. It is attached by a turning-joint to the collar F, which turns with the shaft G, and slides up 
 and down upon it. H, a bevel-wheel in geer with the bevel-wheel I, and giving motion to the shaft G. 
 K, a lever for lifting up the agitator or stirrer E. e, a catch for holding up the lever K, when it has 
 been raised to a proper height. 
 
 Fig. 2981, front elevation of the wedge seed-crushing machine, or wedge-press. 
 
 Fig. 2982, section, in the line XX of Fig. 2983. 
 
 A A, upright guides, or frame-work of wood. B B, side guide-rails. D, driving stamper of wood 
 which presses out the oil ; C, spring stamper, or relieving wedge, to permit the bag to be taken out 
 when sufficiently pressed. E is the lifting-shaft, having rollers b b b b , Fig. 2982, which lift the stampers 
 by the cams a a, Fig. 2982. F is the shaft from the power-engine, on wnich the lifters are fixed. G is 
 the cast-iron press-box, in which the bags of seed are placed for pressure, laterally by the force of the 
 wedge. 
 
 In Figs. 2981 and 2984, o is the spring, or relieving wedge, e, lighter rail; d, lifting-rope to ditto; 
 ffff flooring overhead, g, the back iron or end-plate, minutely perforated, h, the horse-hair bags, 
 (called hairs,) containing the flannel bag charged with seed ; i, the dam-block ; m, the spring-wedge. 
 
 Fig.2983 , A, upright guides ; 0 and D, spring and driving stampers ; E, lifting-roller ; F, lifting-shaft, : 
 a a, cams of stampers. 
 
 Fig. 2984, a view of one set of the wedge-boxes, or presses, supposing the front of them to be removed, 
 o, driving-wedge ; g, back iron ; h, hairs ; i, dam-block ; k, speering or oblique block, between the two 
 stampers ; l and n, ditto ; rn. spring-wedge. 
 
 Vol. II.— 29 
 
450 
 
 OIL TEST. 
 
 When in the course of a few minutes the bruised seeds are sufficiently heated in the pans, the doubl« 
 door F F is withdrawn, and they are received in the bags below the aperture G. These bags are made 
 of strong twilled woollen cloth, woven on purpose. They are then wrapped in a hair-cloth, lined with 
 .eather. 
 
 The first pressure requires only a dozen blows of the stamper, after which the pouches are left alone 
 for a few minutes till the oil has had time to flow out ; in which interval the workmen prepare fresh 
 bags. The former are then unlocked, by making the stamper fall upon the loosening wedge or key to. 
 
 2933. 
 
 The weight of the stampers is usually from 500 to 600 pounds ; and the height from which they fall 
 upon the wedges is from 16 to 21 inches. 
 
 Such a mill as that now described can produce a pressure of from 50 to 15 tons upon each cake of tho 
 following dimensions: 8 inches in the broader base, 1 inches in the narrower, 18 inches in the height; 
 altogether nearly 140 square inches in surface, and about £ of an inch thick. 
 
 Adulteration of oils. — M. Heidenreich has found in the application of a few drops of sulphuric acid to 
 a film of oil, upon a glass plate, a means of ascertaining its purity. The glass plate should be laid upon 
 a sheet of white paper, and a drop of the acid let fall on the middle of ten drops of the oil to be tried. 
 
 With the oil of rape-seed and turnip-seed, a greenish-blue ring is gradually formed at a certain dis- 
 tance from the acid, and some yellowish-brown bands proceed from the centre. 
 
 With oil of black mustard, in double the above quantity, also a bluish-green color. 
 
 With whale and cod oil, a peculiar centrifugal motion, then a red color, increasing gradually in inten- 
 sity ; and after some time it becomes violet on the edges. 
 
 With oil of cameline, a red color, passing into bright yellow. 
 
 Olive-oil, pale yellow, into yellowish green. 
 
 Oil of poppies and sweet almonds, canary yellow, passing into an opaque yellow. 
 
 Of linseed, a brown magma, becoming black. 
 
 Of tallow or oleine, a brown color. 
 
 In testing oils, a sample of the oil imagined to be present should be placed alongside of the actual 
 oil, and both be compared in their reactions with the acid. A good way of approximating to the" knowl- 
 edge of an oil is by heating it, when its peculiar odor becomes more sensible. 
 
 OIL TEST. The most valuable quality in an oil intended for the lubrication of machinery is perma- 
 nent fluidity. That oil which will for the greatest length of time remain fluid in contact with the iron 
 or brass is, without doubt, the most useful for the purpose. Hence the necessity of including the ele- 
 ment of time in any experiment on the comparative value of such oils. 
 
 Some idea may be formed of the importance of having the means of arriving at correct conclusions 
 on this subject, when we know that in some spinning establishments there are upwards of 50,000 spin- 
 dles in motion at the rate of 4000 or 5000 revolutions per minute ! The slightest defect in the quality 
 of the oil in such a case, by its becoming viscid, tells in the most serious way upon the quantity of fuel 
 consumed in generating the power required to maintain at this high velocity such a multitude of moving 
 parts. The slight increase of fluidity consequent on the rise of temperature, caused by the lighting of 
 the gas in the rooms of a cotton-mill, makes a difference of several horses-power in the duty of the en- 
 gine of an extensive establishment. 
 
 The oil test we have now to describe, and which is an invention of Mr. Nasmyth’s, consists of a plate 
 of iron 4 inches wide by 6 feet long, on the upper surface of which six equal-sized grooves are planed. 
 This plate is placed in an inclining position, say 1 inch in 6 feet. The mode of using it is as follows : — 
 Suppose we have six varieties of oil to test, and we are desirous to know which of them will, for the 
 longest time, retain its fluidity when in contact with iron and exposed to the action of the air ; all we 
 have to do is to pour out simultaneously at the upper end of each inclined groove an equal quantity of 
 each of the oils under examination. This is very conveniently and correctly done by means of a row of 
 small brass tubes. The six oils then make a fair start on their race down hill ; some get ahead the first 
 day, and some keep ahead the second and third day, but on the fourth or fifth day the truth begins to come 
 out ; the bad oils, whatever good progress they may have made at the outset, come soon to a stand- 
 still by their gradual coagulation, while the good oil holds on its course ; and at the end of eight or ten 
 days there is no doubt left as to which is the best ; it speaks for itself, having distanced its competitors 
 by a long way. Linseed oil, which makes capital progress the first day, is set fast after having travelled 
 18 inches, while second-class sperm beats first-class sperm by 14 inches in nine days, having traversed 
 in that time 5 feet 8 inches down the hill. The following table will shew the state of the oil-race after 
 a nine days’ run : 
 
ORTHOCHRONOGRAPH. 
 
 45] 
 
 Results of Oil Test. 
 
 Description of Oil. 
 
 First. 
 
 Second. 
 
 Third. 
 
 Fourth. 
 
 Fifth. 
 
 Sixth. 
 
 Seventh. 
 
 Eighth. 
 
 Ninth. 
 
 
 ft. 
 
 in. 
 
 
 in. 
 
 ft. 
 
 in. 
 
 ft. 
 
 in. 
 
 ft. 
 
 in. 
 
 ft. 
 
 in. 
 
 «. 
 
 in. 
 
 ft. 
 
 in. 
 
 ft. 
 
 in. 
 
 Best sperm oil 
 
 2 
 
 8 i 
 
 4 
 
 2 
 
 4 
 
 5f 
 
 4 
 
 6 
 
 4 
 
 6 
 
 4 
 
 6 
 
 4 
 
 u y 
 
 Stat. 
 
 
 i 
 
 Common sperm oil 
 
 i 
 
 7 
 
 3 
 
 9 
 
 4 
 
 04 
 
 4 
 
 11 
 
 5 
 
 H 
 
 5 
 
 4 
 
 5 
 
 
 5 
 
 7® 
 
 5 
 
 8 
 
 Galiopoli oil 
 
 0 
 
 10 J 
 
 1 
 
 24 
 
 1 
 
 6 
 
 1 
 
 64 
 
 i 
 
 n 
 
 i 
 
 84 
 
 1 
 
 9 
 
 1 
 
 94 
 
 i 
 
 94 
 
 Lard oil 
 
 0 
 
 104 
 
 0 
 
 104 
 
 0 
 
 10 J 
 
 0 
 
 104 
 
 0 
 
 114 
 
 Stat. 
 
 
 
 
 
 
 
 Rape oil 
 
 1 
 
 24 
 
 1 
 
 04 
 
 1 
 
 7 
 
 1 
 
 n 
 
 1 
 
 74 
 
 1 
 
 74 
 
 1 
 
 74 
 
 1 
 
 74 
 
 Stat. 
 
 Linseed oil 
 
 1 
 
 64 
 
 1 
 
 6 
 
 1 
 
 04 
 
 1 
 
 64 
 
 1 
 
 64 
 
 1 
 
 64 
 
 1 
 
 64 
 
 _st 
 
 at. 
 
 
 
 For nice machinery nothing has been found to equal the best spermaceti oil, and it is a mistaken econ- 
 omy which applies inferior oil to good machinery. 
 
 OMNIBUS CANE. Invented by S. W. Francis of New York, to enable a passenger at the extremity 
 of the stage to pass up his fare to the driver without incommoding others. The cane is a common ser- 
 viceable stick. Fig. 2984 represents the lower end of the cane ; m is the receptacle for the coin, here, 
 three cent pieces, which are put in by removing the bottom d, and the spring i and follower j, which, 
 after the insertion of say 40 coin, are replaced. At the upper end of the cane is a small stud 6, which 
 on being depressed gives a longitudinal motion to the rod or wire a , which withdraws h from the opening 
 c, gaged to the thickness of two coins, which are thrust out by the bell-crank g. The small spiral 
 spring, as the stud is relieved, presses li against the coin till taken out by the driver. 
 
 OPSIOMETER. An instrument for measuring the extent of the limits of distinct vision in different 
 individuals. The principle of M. Lehot’s contrivance depends on the appearance presented by a straight 
 line placed very near the eye, in the direction of its axis ; and the principle is carried into practice by 
 placing a thread of white silk on a narrow rule covered with black velvet, and furnished with a suitable 
 apparatus for marking the exact points at which the thread begins and ceases to-be distinctly seen, when 
 held in a certain position with respect to the eye. 
 
 ORDINATE. In geometry, a straight . line drawn from any point in a curve perpendicularly tc 
 another straight line, which is called the absciss. The absciss and ordinate together are called the co- 
 ordinates of the point. 
 
 ORDNANCE. Cannon, Great Guns, Artillery. The size of field guns as established in 1827 in 
 the French service, are 8 and 12 pounders, 18 calibres long, and weight of metal 150 times that of the 
 shot. The English field artillery is almost entirely 9 pounders, 17 calibres long, and weight of metal 168 
 times that of the shot. The Prussian service use 6 and 12 pounders, 18 calibres long, and weight of 
 metal 145 times that of the shot. The common charge is 4 of the weight of the ball. 
 
 For battery and siege service, as also in the navy, much heavier ordnance is used; from 24 up to 68 
 pounders. The Dahlgreen guns recently introduced into our navy are very short guns, in shape like a 
 bottle nine-pin, of very large calibre, from 9 to 11 inches. The English 32 pounder is 9 feet long, and 
 weighs*50 cwt. ; the 68 pounder is 10 feet 10 inches long, and weighs 112 cwt. The Paixhan gun is in- 
 tended for the discharge of hollow shot or shell : it is chambered ; that is, there is a chamber, for the recep- 
 tion of the charge, of less calibre than the bore of the piece. Howitzers are short pieces, intended to throw 
 shell at an elevation of from 10° to 30°, and are fixed on carriages. Mortars are still shorter pieces fixed 
 to blocks, intended to throw shell at an elevation exceeding 20°, and sometimes even to 60“ ; they are 
 both chambered ordnance. Howitzers seldom exceed 8 inches in calibre ; Mortars are bored up to 13, 
 15, or even more inches in diameter. See Guns and Gunpowder. 
 
 ORTHOCHRONOGRAPH. This instrument has for its object the ascertaining of correct time. 
 Its property is derived from the intersection of a curvilinear line at two points by the circular transit 
 of a solar ray. The instrument consists of two horizontal circular plates parallel to each other. The 
 upper one a, has an aperture for the passage of a solar ray ; the lower one b, has three pair of semi- 
 circular lines, for the purpose of making observations. The lower plate b, is supported by a pillar c, 
 resting on a tripod, furnished with three adjusting screws d ef. The upper plate a is raised or lowered 
 by means of a rack g, working out of the pillar c, by means of a pinion and friction rollers, acted upon 
 by the milled head h. 
 
 For taking an observation, place the instrument upon any firm support, with the letters N and S as 
 nearly north and south as may be ; but rigid accuracy in this respect is by no means essential. By 
 means of a spirit-level and the adjusting screws d e f. bring the plate b into a horizontal position ; then 
 raise or lower the plate a until the sun’s ray is in contact with the line on which it is intended to make 
 
452 
 
 PACKING. 
 
 the observation, as at A in the diagram, fig. 2986, or until the ray appears within the double line a» 
 at A, fig. 2987. In either case, note the hour, minute, and second, when the ray is at A ; leaving the in- 
 strument undisturbed, the sun’s ray will traverse the plate in the direction of the arrow until it arrives at 
 the point A', when the time is again to be accurately noted. Add the results of the two observation'’ 
 
 together, and divide by 2 ; the difference between this result and 12 hours will show the error of the 
 clock as compared with solar time, which being corrected by the necessary equations, (of which very 
 complete tables are given in the descriptive pamphlet which accompanies the instrument,) will give 
 either mean or siderial time, as may be desired. 
 
 OSCILLATION, CENTRE OF. The centre of oscillation is that point in a vibrating body into 
 which, if the whole were concentrated and attached to the same axis of motion, it would then vibrate 
 in the same time the body does in its natural state. The centre of oscillation is situated in a right line 
 passing through the centre of gravity, and perpendicular to the axis of motion. 
 
 OYSTER-OPENER, Picaclt’s. Amongst the extensive col- 
 lections of the products of industry, agriculture, and manufac- 
 tures of 1849, exhibited in Paris, is a peculiar mechanical con- 
 trivance for opening oysters, which we have engraved, fig. 2988, 
 to show how judiciously mechanical talent may be exercised in 
 the improvement of articles of an humble class. The instrument, 
 which is the invention of M. Picault, consists of two levers bent 
 semicircularly at one end, and hinged together. In the curved 
 portion of one of these levers is a narrow recess, of a size suffi- 
 cient to receive the edge of an oyster, as shown ; and on the other 
 lever, exactly opposite to this recess, is fixed an oblique knife, 
 which, on drawing the two straight ends or handles of the levers 
 together, enters the joint of the shells, and divides them at once. 
 
 PACKING, METALLIC. Patented by Messrs. Allen & Noyes 
 in 1849. By an examination of the accompanying drawing, its 
 principle will be easily understood. Fig. 2989 a is the cylinder 
 cover, b is a matrix of cast-iron, c c &c., a series of rings, and d 
 a piston-rod. Its application is very simple : the bottom of the 
 inside of the stuffing-box, instead of being curved in the usual 
 way, is turned square with the rod on which the cast-iron matrix 
 is fitted and ground on steam-tight ; the diameter of the lower 
 part of the stuffing-box and the inside of the gland is made some 
 what larger than the rod ; and the stuffing-box the same amount 
 larger than the outside of the matrix ; the rings are made of a com- 
 position softer than Babbitt’s metal, and are cast in two pieces, as 
 shown in fig. 2990. It will be observed, the upper ring in which the 
 gland screws enters the matrix about an eighth of an inch, and the 
 top is left the same diameter as the top of the matrix on the inside. 
 
 In its operation, as the matrix is ground on the cylinder cover, 
 and the inside of the rings made the same diameter as the rod, it is 
 kept steam-tight; the rod working through the 2990 
 rings, and being so much the harder metal, keeps 
 perfectly smooth ; the rings are kept from being /' f X A 
 
 worn by any irregularity of motion, by the play L ' \ 2 
 
 allowed in the stuffing-box for the matrix. In 
 screwing down the gland, which must be done 
 lightly, as the rings are conical and left open, they 
 will all press towards the rod, and in time the up- 
 per will take the place of the lower ring. In a 
 stuffing-box of any kind, the great desideratum is 
 to keep it tight, taking care not to cause the packing to scratch the rod, as it always does more or less 
 in using hemp, nor to create an unnecessary amount of friction. This packing effectually accomplishes 
 these, and gives the engineer little or no trouble. 
 
PAPER MACHINES. 
 
 453 
 
 PAPER, MANUFACTURE OF. Till within the last thirty years, the linen and hempen rags from 
 which paper was made, were reduced to the pasty state of comminution requisite for this manufacture 
 by mashing them with water, and setting the mixture to ferment for many days in close vessels, where- 
 by they underwent, in reality, a species of putrefaction. It is easy to see that the organic structure of 
 the fibres would be thus unnecessarily altered, nay, frequently destroyed. The next method employed 
 was to beat the rags into a pulp by stamping-rods, shod with iron, working in strong oak mortars, and 
 moved by water-wheel machinery. So rude and ineffective was the apparatus, that forty pairs of stamps 
 were required to operate a night and a day, in preparing one hundred weight of rags. The pulp or 
 paste was then diffused through water, and made into paper by methods similar to those still practised 
 in the small hand-mills. 
 
 About the middle of the last century, the cylinder or engine mode, as it is called, of comminuting rags 
 into paper pulp, was invented in Holland ; which was soon afterwards adopted in France, and at a later 
 period in England. 
 
 The first step in the paper manufacture is the sorting of the rags into four or five qualities. At fhe 
 mill they are sorted again more carefully, and cut into shreds by women. For this purpose a table- 
 frame is covered at top with wire-cloth, containing about nine meshes to the square inch. To this frame 
 a long steel blade is attached in a slanting position, against whose sharp edge the rags are cut into 
 squares or fillets, after having their dust thoroughly shaken out through the wire-cloth. Each piece of 
 rag is thrown into a certain compartment of a box, according to its fineness ; seven or eight sorts being 
 distinguished. 
 
 The sorted rags are next dusted in a revolving cylinder surrounded with wire-cloth, about six feet 
 long, and four feet in diameter, having spokes about 20 inches long attached at right angles to its axis. 
 These prevent the rags from being carried round with the case, and beat them during its rotation ; so 
 that in half an hour, being pretty clean, they are taken out by the side door of the cylinder, and trans- 
 ferred to the engine, to be first washed and next reduced into a pulp. For fine paper, they should be 
 previously boiled for some time in a caustic ley, to cleanse and separate their filaments. 
 
 Wrigley’s rag-machine is shown in Figs. 2996, 2997, 2998, and 2999. Fig. 2996 is a side elevation; 
 Fig. 2997 a transverse section, taken lengthwise through nearly its middle ; Fig. 2998 a plan view of 
 
 2996. 
 
 the apparatus detached upon a larger scale ; and Fig. 2999 is an elevation. The vessel in which the 
 rags are placed is shown at a a, and in about the centre of this vessel the beating or triturating roll b b 
 is placed ; it is surrounded with the blades or roll-bars c c, Fig. 2997. The roll is mounted upon a shaft 
 d d, one end of which is placed in a pedestal or bearing on the further side of the chamber a , and the 
 other in a bearing upon the arm or level e e*. Fig. 2996, which is supported by its fulcrum, at the end 
 e*, in one of the standards//, and at the other end by a pin fixed in the connecting-rod gg. At the 
 
 2997. 
 
 upper end of this connecting-rod there is a cross-piece or head h, having turned pivots at each end, upon 
 which are placed small rollers ii, resting upon a horizontal cam k k, which is made to revolve. This 
 cam k k, by means of its geering, causes the roll b first of all to wash the rags a short time, then to be 
 lowered at whatever rate is desired for breaking the fibres; to be maintained at the lowest point for 
 
454 
 
 PAPER MACHINES. 
 
 the required number of revolutions for beating; and to be raised and retained, as required, for the final 
 purpose of clearing the pulp. The upper or working edge of this cam is to be shaped exactly according 
 to the action required by the engine-roll ; as, for instance, suppose the previous operation of washing to 
 be completed, and the time required for the operation of the rag machine to be three hours, one of which 
 is required for lowering the roll, that, or the first division of the working surface of the cam k k, must 
 be so sloped or inclined that, according to the speed at which it is driven, the rollers upon the cross- 
 head shall be exactly that portion of the time descending the incline upon the cam, and consequently 
 lowering the roll upon the plates n. Fig. 2997 ; and if the second hour shall be required for the roll to 
 beat up the rags, the roll revolving all the time in contact with the pdates, the second division of the 
 cam k k must be so shaped (that is, made level) that the roll shall be allowed to remain, during that 
 period, at its lowest point ; and if the third portion of tire time, or an hour, be required for raising the 
 * " again, either gradually or interruptedly, then the third division of the cam k must be suitably shaped 
 
 2999. 2998. 
 
 or inclined, so as to cause the cross-head to lift the roll during such interval or space of time ; the par- 
 ticular shape of the inclined portions of the cam depending on the manner in which the manufacturer 
 may wish the roll to approach to or recede from the bottom plates during its descent and ascent respect- 
 
 •'•ely. 
 
 Its mode of connection and operation in the rag-engine is as follows : supposing that the rags intended 
 to be beaten up are placed in the vessel a, Fig. 2997, and motion is communicated from a steam-engine 
 or other power, to the further end of the shaft d, the roll b will thus be caused to revolve, and the rags 
 washed, broken, and beaten up, as they proceed from the front weir m, over the bottom plates n, and 
 again wund by the back weir n. There is a small pulley p, upon the near end of the shaft d, round 
 ’.vhick a band q passes, ahd also round another pulley r, upon the cross-shaft s; upon this shaft is a 
 worm t , geering into a worm-wheel u, fixed upon another shaft v, below ; upon the reverse end of which 
 is a pinion w, geering into a spur-wheel x, upon the end of a shaft y ; and upon the centre of this shaft 
 y there is another worm z, geering into a horizontal worm-wheel 1, upon which the cam kk is fixed. 
 Thus it will be seen that the requisite slow motion is communicated to the cam, which may be made to 
 perform half a revolution in three hours ; or it will be evident, that half a revolution of the cam k k 
 may be performed in any other time, according- to the calculation of the geering employed. The shaft 
 may also be driven by hand, so as to give the required motion to the cam. Supposing, now, at the be- 
 ginning of the operation, the cross-head bearing the lever and roll to be at the highest point upon the 
 cam k k, as its revolution commences, the roll will revolve for a short time on the level surface of the 
 cam, and will then be lowered until the cam k k has arrived at that point which governs the time that 
 the roll remains at the lowest point, for the purpose of beating the rags into pulp, and as the cam k k 
 continues to revolve, and thus brings the opposite slope upon the third portion of its working surface 
 into action upon the cross-head, the roll will be raised in order to clear the pulp from knots and other 
 imperfections, and thus complete the operation of the engine. In order to raise the cross-head and roll 
 to the height from which it descended without loss of time, or to lift the cross-head entirely from off the 
 cam when requisite, a lever 2, or other suitable contrivance may be attached to the apparatus, also a 
 shaft may be passed across the rag-engine, and both ends of the roll may be raised instead of one only, 
 as above described. 
 
 In the paper machine of Messrs Bryan Donkin & Co. in Bermondsey, on Fourdrinier’s principle, each 
 machine is capable of making, under the impulsion of any prime mover, all unwatched by a human eye 
 and unguided by a human hand, from 20 to 50 feet in length, by 5 feet broad, of most equable paper in 
 one minute. Of paper of average thickness it turns off 30 feet. 
 
 Fig. 3000, 30 00 2 is an upright longitudinal section, representing the machine in its most complete state, 
 including the drying steam-cylinders, and the compound channelled rollers of Mr. Wilkes, subsequently 
 to be described in detail. The longer figure shows it all in train, when the paper is to be wound up 
 wet upon the reels E E, which, being movable round the centre l of a swing-bar, are presented empty, 
 time about, to receive the tender web. The shorter figure contains the steam or drying cylinders, the 
 points O O of whose frame replace at the points P P the wet-reel frame F F P. 
 
 A is the vat, or receiver of pulp from the stuff-chest. B is the knot-strainer of Ibotson, to clear the 
 pulp before passing on to the wire. G is the hog, or agitator in the vat. The arrows show the course 
 of the currents of the pulp in the vat. I is the apron, or receiver of the water and pulp which escape 
 through the endless wire, and which are returned by a scoop-wheel into the vat. b is the copper lip ol 
 the vat, over which the pulp flows to the endless wire, on a leathern apron extending from this lip to 
 about nine inches over the wire, to support the pulp and prevent its escaping, cc are the bars which 
 bear up the small tube rollers that support the wire, dd are ruler-bars to support the copper rollers 
 
PAPER MACHINES. 
 
 455 
 
 over which the wire revolves. K is the breast-roller, round which the endless wire turns. N is the point 
 where the shaking motion is given to the machine. M is the guide-roller, having its pivots movable 
 laterally to adjust the wire and keep it parallel. L is the pulp-roller, or “ dandy,” to press out water, 
 and to set the paper, r is the place of the second, when it is used. H is the first or wet press, or 
 couching rollers ; the wire leaves the paper here, which latter is couched upon the endless felt p ; and 
 the endless wire o returns, passing round the lower couch-roller. By Mr. Donkin’s happy invention of 
 placing these rollers obliquely, the water runs freely away, which it did not do when their axes were in 
 a vertical line, ee are the deckles, which form the edges of the sheet of paper, and prevent the pulp 
 passing away laterally. They regulate the width of the endless sheet, ff are the revolving deckle- 
 straps. R is the deckle-guide, or driving-pulley, g g are tube-rollers, over which the wire passes, which 
 do not partake of the shaking motion ; and h h are movable rollers for stretching the wire, or brass car- 
 riages for keeping the rollers g g in a proper position. 
 
 C is the second press, or dry press, to expel the water in a cold state. KK, die., are the steam- 
 cylinders for drying the endless sheet, i i are rollers to convey the paper, jj are rollers to conduct 
 the felt, wliich serves to support the paper, and prevent it wrinkling or becoming cockled. D D are 
 the hexagonal expanding reels for the steam-dried paper web, one only being used at a time, and 
 made to suit different sizes of sheets ; l is their swing-fulcrum. F F F F is the frame of the machine. 
 
 The deckle-straps are worthy of particular notice in this beautiful machine. They are composed of 
 many layers of cotton tape, each one inch broad, and together one-half inch thick, cemented with caout- 
 chouc, so as to be at once perfectly flexible and water-tight. 
 
 The upper end of each of the two carriages of the roller L is of a forked shape, and the pivots of 
 the roller are made to turn in the cleft of the forked carriages in such a manner that the roller may 
 be prevented from having any lateral motion, while it possesses a free vibratory motion upwards and 
 downwards ; the whole weight of the roller L being borne by the endless web of woven wire. 
 
 The greatest difficulty formerly experienced in the paper manufacture upon the continuous system 
 of Fourdrinier, was to remove the moisture from the pulp and condense it with sufficient rapidity, so 
 as to prevent its becoming what is called water-galled , and to permit the web to proceed directly to 
 the drying cylinders. Hitherto no invention has answered so well in practice to remove this difficulty 
 as the channelled and perforated pulp-rollers or dandies of Mr. John Wilks, the partner of Mr. Donkin. 
 Suppose one of these rollers (see L, Fig. 8000, and MM, Fig. 3005) is required for a machine which is 
 to make paper 54 inches wide, it must be about 60 inches long, so that its extremities (see Figs.. 3001 
 and 3002 ) may extend over or beyond each edge of the sheet upon which it is laid. Its diameter may 
 be 7 inches. About 8 grooves, each l-16th of an inch wide, are made in every inch of the tube; and 
 they are cut to half the thickness of the copper, with a rectangularly shaped tool. A succession o? 
 ribs and grooves are thus formed throughout the whole length of the tube. A similar succession is 
 then made across the former, but of 24 in the inch, and on the opposite surface of the metal, which, 
 by a peculiar mode of management, had been prepared for that purpose. As the latter grooves are 
 cut as deep as the former, those on the inside meet those on the outside, crossing each other at right 
 angles, and thereby producing so many square holes; leaving a series of straight copper ribs on the in- 
 terior surface of the said tube, traversed by another series of ribs coiled round them on the outside, 
 forming a cylindrical sieve made of one piece of metal. The rough edges of all the ribs must be 
 rounded off with a smooth file into a semicircular form. 
 
 Figs. 3002 and 3001, A A are portions of the ribbed copper tube. Fig. 3002 shows the exterior, and 
 Fig. 3001 the interior surface; bb and bb show the plain part at each of the ends, where it is made 
 fast to the brass rings by rivets or screws. C C are the rings with arms, and a centre-piece in each, 
 for fixing the iron pivot or shaft B ; one such pivot is fixed by riveting it in each of the centre-pieces 
 of the rings, as shown at c, Fig. 3001 ; so that both the said pieces shall be concentric with the rings, 
 and have one common axis with each other and with the roller. At a a a groove is turned in each of 
 the pivots, for the purpose of suspending a weight by a hook, in order to increase the pressure upon 
 the paper, whenever it may be found necessary. 
 
 Fig. 3003 is an end view, showing the copper tube and its internal ribs A A, the brass rings C C, 
 arm D, centre-piece E, and pivot B. Fig. 8004 is a section of the said ring, with the arms, &c. 
 
 The roller is shown at L, Fig. 3000, as lying upon the surface of the wire-web. The relative position 
 of that perforated roller, and the little roller b over which it lies, is such that the axis of L is a little 
 to one side of the axis of b, and not in the same vertical plane, the latter being about an inch nearer 
 the vat end. Hence, whenever the wire-web is set in progressive motion, it will cause the roller L to 
 revolve upon its surface ; and as the paper is progressively made, it will pass onwards with the web 
 under the surface of the roller. Thus the pulpy layer of paper is condensed by compression under the 
 ribbed roller ; while it transmits its moisture through the perforations, it becomes sufficiently compact 
 to endure the action of the wet-press rollers H H, and also acquires the appearance of parallel lines, 
 as if made by hand in a laid mould. 
 
 Mr. Wilks occasionally employs a second perforated roller in the same machine, which is then placed 
 at the dotted lines i i i. 
 
 The patentee has described in the same specification a most ingenious modification of the said roller, 
 by which he can exhaust the air from a hollowed portion of its periphery, and cause the paper in its 
 passage over the roller to undergo the sucking operation of the partial void, so as to be remarkably 
 condensed ; but he has not been called upon to apply this second invention, in consequence of the per- 
 fect success which he has experienced in the working of the first. 
 
 The following is a more detailed illustration of Mr. Wilks’s improved roller : 
 
 Fig. 3005 represents two parts of his double-cased exhausting cylinder. This consists of two copper 
 tubes, one nicely lining the other ; the inner being punched full of round holes, as at K K, where that 
 tube is shown uncovered ; a portion of the inner surface of the same tube is shown at L L. In this figure 
 also, two portions of the outer tube are shown at M M and N N, tire former being an external, and the 
 
456 
 
 PAPER MACHINES. 
 
PAPER MACHINES. 
 
 457 
 
 latter an internal view. Here we see that the external tube is the ribbed perforated one already de- 
 scribed ; the holes in the inner tube being made in rows to correspond with the grooves in the outer. 
 The holes are so distributed that every hole in one row shall be opposite to the middle of the space left 
 between two holes in the next row, as will appear from inspection of the figure. The diameter of cacti 
 of the punched holes somewhat exceeds the width of each rib in the inside of the outer cylinder, and 
 every inside groove of this tube coincides with a row of holes in the former, which construction permits 
 the free transudation or percolation of the water out of the pulp. At each end of this double-case cyl- 
 inder a part is left at N N plain without, and grooved merely in the inside of the outer tube. The 
 smooth surface allows the brass ends to be securely fixed ; the outer edge of the brass ring fits tight 
 into the inside of the end of the cylinders. 
 
 On the inside of each of these rings there are four pieces which project towards the centre or axis of 
 the cylinder, two of which pieces are shown at a a, Fig. 3005, in section, b b is a brass ring with four 
 arms cccc, and a boss or centre-piece dd. The outer edge of the last-mentioned ring is also turned 
 cylindrical, and of such a diameter as to fit the interior of the former ring oo. The two rings are 
 securely held together by four screws, e e is the hollow iron axle or shaft upon which the cylinder re- 
 volves. Its outside is made truly cylindrical, so as to fit the circular holes in the bosses d d of the rings 
 and arms at each end of the cylinder. Hence, if the hollow shaft be so fixed that it will not turn, the 
 perforated cylinder is capable of having a rotatory motion given to it round that shaft. This motion is 
 had recourse to when the vacuum apparatus is employed. But otherwise the cylinder is made fast to 
 the hollow axle by means of two screw-clamps. To one end of the cylinder, as at p, a toothed wheel is 
 attached for communicating a rotatory motion to it, so that its surface motion shall be the same as that 
 of the paper web; otherwise a rubbing motion might ensue, which would wear and injure both. 
 
 The paper stuff or pulp is allowed to flow from the vat A, Fig. 3000, on to the surface of the endless 
 wire-web, as this is moving along. The fines o o, Fig. 3000, show the course of the motion of the web, 
 which operates as a sieve, separating to a certain degree the water from the pulp, yet leaving the latter 
 in a wet state till it arrives at the first pair of pressing-rollers II H, between which the web with its 
 sheet of paper is squeezed. Thick paper, in passing through these rollers, was formerly often injured 
 by becoming water-galled, from the greater retention of water in certain places than in others. But 
 Messrs. Donkin’s cylinder, as above described, has facilitated vastly the discharge of the water, and 
 enabled the manufacturer to turn off a perfectly uniform smooth paper. 
 
 In Fig. 3000, immediately below the perforated cylinder, there is a wooden water-trough. Along one 
 side of the trough a copper pipe is laid, of the same length as the cylinder, and parallel to it ; the dis- 
 tance between them being about one-fourth of an inch. The side of the pipe facing the cylinder is per- 
 forated with a fine of small holes, which transmit a great many jets of water against the surface of the 
 cylinder, in order to wash it and keep it clean during the whole continuance of the process. 
 
 The principle adopted by John Dickinson for making paper, is different from that of Fourdrinier. It 
 consists in causing a polished hollow brass cylinder, perforated with holes or slits, and covered with wire- 
 cloth, to revolve over and just in contact with the prepared pulp ; so that by connecting the cylinder 
 with a vessel exhausted of its air, the film of pulp, which adheres to the cylinder during its rotation, 
 becomes gently pressed, whereby the paper is supposed to be rendered drier, and of more uniform 
 thickness, than upon the horizontal hand-moulds or travelling wire-cloth of Fourdrinier. When sub- 
 jected merely to agitation, the water is sucked inwards through the cylindric cage, leaving the textile 
 filaments so completely interwoven as, if felted among each other, that they will not separate without 
 breaking, and when dry they will form a sheet of paper of a strength and quality relative to the nature 
 and preparation of the pulp. The roll of paper thus formed upon the hollow cylinder is turned off con- 
 tinuously upon a second solid one covered with felt, upon which it is condensed by the pressure of a 
 third revolving cylinder, and is thence delivered to the drying rollers. 
 
 Mr. Ibotson, of Poyle, paper manufacturer, obtained a patent, see B, Fig. 3000, which has proved very 
 successful for a peculiar construction of a sieve or strainer. Instead of wire meshes, he uses a series of 
 bars of guii-metal, laid in the bottom of a box very closely together, so that the upper surfaces or the 
 flat sides may be in the same plane, the edge of each bar being parallel with its neighbor, leaving par- 
 allel slits between them of from about l-JOth to l-100th of an inch in width, according to the fineness 
 or coarseness of the paper stuff to be strained. As this stuff is known to consist of an assemblage of 
 very fine flexible fibres of hemp, flax, cotton, &c., mixed with water, and as, even in the pulp of which 
 the best paper is made, the length of the said fibres considerably exceeds the diameter of the meshes of 
 which common strainers are formed, consequently the longest and most useful fibres were formerly lost 
 to the paper manufacturer. Mr. Ibotson’s improved sieve is employed to strain the paper stuff pre- 
 viously to its being used in the machine above described, (see its place at B in the vat.) When the 
 strainer is at work, a quick vertical and lateral jogging motion is given to it, by machinery similar to 
 the jogging screens of corn-mills. 
 
 Since the lateral shaking motion of the wire-web in the Fourdrinier machine, as originally made, was 
 injurious to the fabric of the paper, by bringing its fibres more closely together breadthwise than length- 
 wise, thus tending to produce long ribs or thick streaks in its substance, it was proposed to give a rapid 
 up-and-down movement to the travelling web of pulp; and this has been introduced into Mr. Donkin's 
 machines. 
 
 Mr. Dickinson obtained a patent for a method of uniting face to face two sheets of pulp by means of 
 machinery, in order to produce paper of extraordinary thickness. Two vats are to be supplied with 
 paper stuff as usual ; in which two hollow barrels or drums are made to revolve upon axles driven by 
 any first mover ; an endless felt is conducted by guide-rollers, and brought into contact with the drums ; 
 the first drum gives off the sheet of paper pulp from its periphery to the felt, which, passing over a 
 pressing-roller is conducted by the felt to that part of a second drum which is in contact with another 
 pressing-roller. A similar sheet of paper pulp is now given off from the second drum, and it is brought 
 into contact with the former by the pressure of its own roller. The two sheets of paper pulp thus 
 
458 
 
 PAPER MACHINES. 
 
 united are carried forwards by the felt over a guide-roller, and onwards to a pair of pressing-rollers 
 where, by contact, the moist surface of the pulp are made to adhere, and to constitute one double thick 
 sheet of paper, which, after passing over the surfaces of hollow drums, heated by steam, becomes dry 
 and compact. The rotatory movements of the two pulp-lifting drums must obviously be simultaneous, 
 but that of the pressing-rollers should be a little faster, because the sheets extend by the pressure, and 
 they should be drawn forwards as fast as they are delivered, otherwise creases would be formed. Upon 
 this invention is founded Mr. Dickinson’s ingenious method of making safety-paper for post-office stamps, 
 by introducing silk fibres, <fcc., between the two laminae. 
 
 The following contrivance of the same manufacturer is a peculiarly elegant mechanical arrangement, 
 and consists in causing the diluted paper pulp to pass between longitudinal apertures, about the hun- 
 dred-and-fifteenth part of an inch wide, upon the surface of a revolving cylinder. 
 
 The pulp being dilated to a consistency suitable for the paper machine, is delivered into a vat, of 
 which the level is regulated by a waste-pipe, so as to keep it nearly full. From tiiis vat there is no 
 other outlet for. the pulp except through the wire-work periphery of the revolving cylinder and thence 
 out of each of its ends into troughs placed alongside, from which it is conducted to the machine destined 
 to convert it into a paper web. 
 
 The revolving cylinder is constructed somewhat like a squirrel cage, of circular rods, or an endless 
 spiral wire, strengthened by transverse metallic bars, and so formed that the spaces between the rings 
 are sufficient to allow the slender fibres of the pulp to pass through, but are narrow enough to intercept 
 the knots and other coarse impurities, which must of course remain and accumulate in the vat. The 
 spaces between the wires of the squirrel cage may vary from the interval above stated, which is in- 
 tended for tlie finest paper, to double the distance for the coarser kinds. 
 
 It has been stated that the pulp enters the revolving cylinders solely through the intervals of the 
 wires in the circumference of the cylinder ; these wires or rods are about three-eighths of an inch broad 
 without, and two-eighths within, so that the circular slits diverge internally. The rods are one-quarter 
 of an inch thick, and are riveted to the transverse bars in each quadrant of their involution, as well as 
 at their ends to the necks of the cylinder. 
 
 During the rotation of the cylinder its interstices would soon get clogged with the pulp, were not a 
 contrivance introduced for creating a continual vertical agitation in the inside of the cylinder. This is 
 effected by the up-and-down motion of an interior agitator or plunger, nearly long enough to reach from 
 the one end of the cylinder to the other, made of stout copper, and hollow, but water-tight. A metal 
 bar passes through it, to whose projecting arm at each end a strong link is fixed ; by these two links it 
 is hung to two levers, in such a way that when the levers move up and down they raise and depress 
 the agitator, but they can never make it strike the sides of the cylinder. Being heavier than its own 
 talk of water, the agitator, after being lifted by the levers, sinks suddenly afterwards by its weight 
 alone. 
 
 The agitator’s range of up-and-down movement should be about one inch and a quarter, and the 
 number of its vibrations about 80 or 100 per minute ; the flow of the pulp through the apertures is sud- 
 denly checked in its descent and promoted in its ascent, with the effect of counteracting obstructions 
 between the ribs of the cylinder. 
 
 The sieve-cylinder has a toothed wheel fixed upon the tubular part of one of its ends, which works 
 between two metal flanches made fast to the wooden side of the vat, for the pjurpose of keeping the 
 pulp away from the wheel ; and it is made to revolve by a pinion fixed on a spindle, which, going across 
 the vat, is secured by two plummer-blocks on the outside of the troughs, and has a rotatory motion given 
 to it by an outside rigger or pulley, by means of a strap from the driving-shaft, at the rate of 40 or 
 50 revolutions per minute. This spindle has also two double eccentrics fixed upon it, immediately 
 under the levers, so that in every revolution it lifts those levers twice, and at the same time lifts the 
 agitator. 
 
 The diameter of the sieve -cylinder is not very material, but 14 inches have been found a convenient 
 size ; its length must be regulated according to the magnitude of the machine which it is destined to 
 supply with pulp. 
 
 Metal flanches are firmly fixed to the sides of the vat, with a water-tight joint, and form the bearings 
 in which the cylinder works. 
 
 Mr. Dickinson obtained a patent in 1840 for a new mode of sizing paper continuously, in an air-tight 
 vessel, (partly exhausted of air,) by unwinding a scroll of dried paper from a reel, and conducting it 
 through heated size ; then, after pressing out the superfluous size, winding the paper on to another reeL 
 
 A longitudinal section of the apparatus employed for this purpose is represented in Fig. 3006, where 
 a is the air-tight vessel ; b, the reel upon 
 which the paper to be sized is wound ; 
 whence it proceeds beneath the guide- 
 roller c, and through the warm size to 
 another guide-roller d. It thence as- 
 cends between the press-rolls ef, (by 
 whose revolution the paper is drawn 
 from the reel b,) and is w r ound upon the 
 reel ff. A float h is suspended from the 
 cross-bar i of the vessel a, for the pur- 
 pose of diminishing the surface of size 
 exposed to evaporation ; and beneath 
 the bottom of the vessel is an inclosed 
 space j, into which steam or hot water 
 is introduced for maintaining the tem- 
 Derature of the size. 
 
PAPER MACHINES. 
 
 459 
 
 PAPER MACHINES, regulation of. It is found in practice to be difficult to regulate the motion of 
 the Foudrinier, and other machines, in common use, for the manufacture of endless paper. When the 
 flow of pulp upon any machine is uniform, an acceleration of its motion will make the paper thin, 
 whilst a retardation will make it thick. Hence it is of the utmost importance, in order to make paper 
 of even weight and thickness, that when the flow of the pulp is uniform, the machine shall move uni- 
 formly at the same speed. Rut if. by any contrivance, the flow of the pulp could be augmented, or 
 checked, just in the same proportion as the machine moves slower or faster, it is evident that the 
 necessary relation between its speed, and the quantity of pulp thrown on, might be effected and main- 
 tained. Consequently, two modes of obtaining the requisite uniformity in the thickness and weight of 
 the endless sheet of paper suggest themselves. 
 
 I. To regulate the speed of the motor driving the machine. 
 
 II. To regulate the flow of pulp upon the machine. 
 
 The attention of constructors has usually been directed chiefly to the first method; and hence we 
 find the machine-wheels of paper-mills are very frequently tub-wheels, wasting a large amount of water, 
 but nevertheless selected and used on account of the regularity of their motion. With this object also it 
 is almost invariably the practice here to employ an independent wheel to drive the paper machine alone. 
 
 Some attempts have recently been made in this country to regulate endless paper machines by the 
 second method, and accordingly “ pulp regulators ” have been applied with considerable success in 
 several important mills. 
 
 It being, in fact, a desideratum to procure some unobjectionable means of effecting the regulation re- 
 ferred to, we have translated from J. B. Viollet’s Journal des Usines an account of a mechanical con- 
 trivance devised in France for tliis object. 
 
 Regulator for feeding machines making endless paper, by Messrs. Sandford and Varuall, mechanical 
 engineers of Paris . — Whatever care may be taken to render uniform the speed of the motors which 
 drive endless paper machines, and notwithstanding we usually establish for each of these machines a 
 separate water-wheel, constructed of iron, in the best provided works, it has long been impossible to 
 obtain a regularity of motion, and a harmony between the movement of the endless cloth and the feed- 
 ing on of the pulp, so that the paper may possess uniformly the same thickness. 
 
 * From this resulted a serious imperfection, consisting of a marked inequality between the different 
 parts of the long band of paper, and consequently, between the sheets into which it is cut. We con- 
 ceived that this inequality was not only a fault, but also that it exposed the manufacturers to disputes 
 not arising from any fault on their part. 
 
 In fact, to cause the velocity of the machines, and consequently, the strength of the paper to vary, it 
 was enough that the resistances opposed by the materials were not constant, or that the stream of water 
 happened to be disturbed. 
 
 It is to avoid these difficulties and inconveniences that Sandford and Varrall have invented the 
 apparatus represented in Figs. 3007, 3008, 3009, 3010, 3011, and 3012. 
 
 3007. 
 
 O 
 
 This apparatus consists principally of a wheel R, provided with a. certain number ot scoops e, which 
 take up the diluted pulp, elevate it, and pour it into a receptacle, from which the filter c conducts it 
 into the vat for working the paper machine. The motion of the wheel R being connected both with 
 that of the water-wheel, and of the endless cloth, it is easy to see that if the receiver accelerates, or 
 retards its motion, in consequence of some variation in the level or quantity of the water above, the 
 rapidity of the revolution of the scoop-wheel R, and the motion of the endless cloth of the machine, will 
 each feel a proportional variation. But as the scoop-wheel for each of its revolutions pours the same 
 quantity of pulp into the filter c of the machine, it is evident that the feeding on of the pulp will aug- 
 ment, or diminish proportionally to the velocity of translation of the endless cloth, and that, conse- 
 quently, the strength of the paper ought to be constant, so long as we do not change the ratio betweeu 
 Die quantity of pulp furnished and the distance moved in a given time by the metallic clotli. 
 
460 
 
 PAPER MACHINES. 
 
 This principle established, the following are the details of the ingenious apparatus of Sandford ana 
 \ T arrall. 
 
 R, as we have said, is the regulating wheel, provided with scoops eee\ this wheel is confined in a 
 drum B, which the pulp enters from the reservoirs A A by the large stop-cocks r r, kept entirely open, 
 so as to maintain sensibly in the drum B the same level as in the reservoirs A A. It is of little im- 
 portance, moreover, if this level be not rigorously equal, nor even if it varies notably in the reservoirs 
 A A ; for, provided the pulp arrives in sufficient quantity, and we must take care that it be always so, 
 each of the scoops, every time they issue from the pulp, only withdraws the same quantity of material. 
 
 3008. 3010. 
 
 We easily conceive how advantageous is this property of the apparatus, since, notwithstanding all the 
 variations of level of the liquid pulp in the reservoir, or stuff-chest, it assures regularity in feeding on 
 the pulp — a regularity which would often be compromised if made dependent solely on this level. 
 
 It is necessary that the relation which ex- 
 ists between the number of revolutions of the 3009. 
 
 scoop-wheel R and the velocity of the endless 
 cloth may be varied, when we wish to alter 
 the strength of the paper. 
 
 To obtain this effect, Sandford and Varrall 
 have controlled the scoop-wheel R by the two 
 parallel cones C and C', which carry the belt d\ 
 the cone C' receiving its motion from the lat- 
 eral shaft established alongside the paper ma- 
 chine, and on which is all the geering which 
 moves the endless cloth, and the other movable 
 
 parts of the machine. 3012. 
 
 It is sufficient to move the belt laterally, (along the cones,) in order to retard or accelerate the rota, 
 tion of the scoop-wheel, without altering the angular velocity of the other movable parts, and thus, 
 consequently, to change the relation in question, and of course the thickness of the paper made. 
 
PAPER MACHINES. 
 
 461 
 
 PAPER CUTTING. The following machine for cutting paper was contrived by J. Dickinson, of Nash 
 Mill. The paper is wound upon a cylindrical roller a, Fig. 3013, mounted upon an axle, supported in an 
 iron frame or standard. From this roller the paper in its breadth is extended over a conducting drum b, 
 also mounted upon an axle turning in the frame or standard, and after passing under a small guide-roller, 
 it proceeds through a pair of drawing or feeding rollers c, which carry it into the cutting machine. 
 
 Upon a table ad, firmly fixed to the floor of the building, there is a series of chisel-edged knives ee e, 
 placed at such distances apart as the dimensions of the cut sheets of paper are intended to be. These 
 knives are made fast to the table, and against them a series of circular cutters fff, mounted in a 
 swinging frame g g, are intended to act. The length of paper being brought along the table over the 
 edges of the knives, up to a stop h, the cutters are then swung forwards, and by passing over the paper 
 against the stationary knives, the length of paper becomes cut into three separate sheets. 
 
 The frame gg, which carries the circular cutters fff, hangs upon a very elevated axle, in order that 
 its pendulous swing may move the cutters as nearly in a horizontal line as possible ; and it is made to 
 vibrate to and fro by an eccentric or crank, fixed upon a horizontal rotary shaft extending over the drum 
 b, considerably above it, which may be driven by any convenient machinery. 
 
 The workmen draw the paper from between the rollers c, and bring it up to the stop h, in the inter- 
 vals between the passing to and fro of the swing-cutters. 
 
 The following very ingenious appara- 
 tus for cutting the paper web trans- 
 versely into any desired lengths, was 
 made the subject of a patent by Mr. E. 
 
 N. Fourdrinier, in June, 1831, and has 
 since been performing its duty well in 
 many establishments. 
 
 Fig. 3014 is an elevation, taken upon 
 one side of the machine; and Fig. 3015 
 is a longitudinal section, aaaa are four 
 reels, each covered with one continuous 
 sheet of paper ; which reels are supported 
 upon bearings in the framework bbb. 
 c c c is an endless web of felt cloth passed 
 over the rollers dddd, which is kept in 
 close contact with the under side of the 
 drum ee, seen best in Fig. 3016. 
 
 The several parallel layers of paper to 
 be cut, being passed between the drum e 
 and the endless felt c, will be drawn off 
 their respective reels and fed into the 
 machine, whenever the driving-band is 
 slid from the loose to the fast pulley 
 upon the end of the main shaft/. But 
 since the progressive advance of the 
 paper-webs must be arrested during the 
 time of making the cross-cut through it, 
 the following apparatus becomes neces- 
 sary. A disk g, which carries the pin or 
 stud of a crank i, is made fast to the end 
 of the driving-shaft /. This pin is set in 
 an adjustable sliding-piece, which may be 
 confined by a screw within the bevelled 
 graduated groove, upon the face of the 
 disk g, at variable distances from the 
 axis, whereby the eccentricity of the 
 stud i, and of course the throw of the 
 crank, may be considerably varied. The 
 crank-stud i is connected by its rody to the 
 swinging curvilinear rack k, which takes 
 into the toothed wheel l that turns freely 
 
 upon the axle of the feed-drum ee. From that wheel the arms mm rise, and bear one or more palls n, 
 which work in the teeth of the great ra + chet-wheel o o, mounted upon the shaft of the drum e. 
 
462 
 
 PARALLEL MOTIONS. 
 
 The crank-plate g being driven round in the direction of its arrow, will communicate a see-saw move- 
 ment to the toothed arc k, next to the toothed wheel l in geering with it, and an oscillatory motion tc 
 the arms m m, as also to their surmounting pall n. 
 
 In its swing to the left hand, the catch of the pall will slide over the slope of the teeth of the ratchet- 
 wheel o ; but in its return to the right hand it will lay hold of these teeth and pull them, with their 
 attached drum, round a part of a revolution. The layers of paper in close contact with the under half ol 
 the drum will be thus drawn forward at intervals, from the reels, by the friction between its surface and 
 the endless felt, and in lengths corresponding to the arc of vibration of the palh The knife for cutting 
 these lengths transversely is brought into action at the time when the swing arc is making its inactive 
 stroke, viz., when it is sliding to the left over the slopes of the ratchet-teeth o. The extent of this 
 vibration varies according to the distance of the crank-stud i from the centre/, of the plate g, because 
 that distance regulates the extent of the oscillations of the curvilinear rack, and that of the rotation of 
 the drum c, by which the paper is fed forwards to the knife apparatus. The proper length of its several 
 layers being by the above-described mechanism carried forward over the bed r of the cutting-knife or 
 shears r v, whose under blade r is fixed, the wiper s, in its revolution with the shaft f lifts the tail of the 
 lever t, consequently depresses the transverse movable blade v, (as shown in Fig. 8015,) and slides the 
 slanting blades across each other obliquely, like a pair of scissors, so as to cause a clean cut across the 
 plies of paper. But just before the shears begin to operate, the transverse boaid u descends to press 
 the paper with its edge, and hold it fast upon the bed r. During the action of the upper blade y 
 against the under r, the fall-board u is suspended by a cord passing across pulleys from the arm y of 
 the bell-crank lever 1 1. Whenever the lifter cam s has passed away from the tail of the bell-crank t, 
 the weight z, hung upon it, will cause the blade v, and the pinching-board w, to be moved up out of the 
 way of the next length of paper, which is regularly brought forward by the rotation of the drum e, as 
 above described. The upper blade of the shears is not set parallel to the shaft of the drum, but 
 obliquely to it, and is, moreover, somewhat curved, so as to close its edge progressively upon that of the 
 fixed blade. The blade v may also be set between two guide-pieces, and have the necessary motion 
 given to it by levers. 
 
 PARALLEL MOTIONS. The following figures exhibit a variety of forms of parallel motions, such 
 as are employed to maintain the rectilineal direction of the piston-rod of a steam-engine, under the 
 constantly varying angular direction of the beam. Contrivances of this kind are required in other cir- 
 cumstances of the conversion of rotatory and alternating angular motion into rectilineal motion, and the 
 converse ; but the absolute necessity there is of guiding the path of piston in the steam-engine, has 
 called forth more attention to the principles and mechanism of parallel motions than would otherwise, 
 in all probability, have been awarded to the subject for other purposes. In the first place, the principle 
 may be briefly indicated. 
 
 Fig. 3016. Given A B D a right angle : it can be demonstrated that if the end A of the right line A I 
 aescend from A to B along the line A B, while the end D moves along the line B D produced, a point C in 
 the middle of the line will describe the circle C G. Hence, if a beam A D has one end sliding in a groove 
 at D, and is connected or jointed at the middle C in a guide B C of half its length, this guide also mov- 
 ing on a joint at B, then in every position of the beam the point C will describe the circle C G, and the 
 point A of the beam will move in a straight line. 
 
 Fig. 3017. In practice, it may be more convenient to have the erl D of the beam fixed to the ena 
 
PARALLEL MOTIONS. 
 
 163 
 
 of a movable bar, as D N, of some feet in length, than to slide in a groove ; for, though the arc described 
 by the end D will deviate a little from a straight line, yet the error produced thereby will be so very 
 small that it can have no bad effect, or even be discovered in practice. 
 
 In the steam-engine there are various modes adopted by means of jointed rods, (fee., different from 
 that described above, for causing the piston-rod, attached to the end of the beam, to move in a straight 
 line, which, although not mathematically correct, are still so very near the truth as to answer the pur- 
 pose wanted exceedingly well ; such a system of jointed rods is generally termed by engineers a par- 
 allel motion. 
 
 Fig. 3018. In the beam aF, which is shown in its three positions, viz., at the middle and the two 
 extremities of tho»stroke, the versed sine a 6 of the arc formed by the extremity of the beam, is termed 
 the vibration, and a piston-rod attached to the beam is made to move in a line bisecting this vibration ; 
 thus, if a piston-rod were attached to the beam aF, cd is the line in which the rod ought to move. 
 
 Fig. 3019 is a general mode of finding the length of the radius-rod G c, and shows the principle upon 
 which parallel motions formed by jointed rods are founded; «F is the beam, a c a strap, one end of 
 which is attached to the beam, and the piston-rod is attached somewhere about the middle, as at b ; 
 the beam is then put in its three positions, and while the point b to which the piston-rod is fixed is kept 
 in the straight line, bisecting the vibration, thft positions of the lower end c of the strap are carefully 
 marked, as at ccc-, then the centre G of the circle passing through these points will be the point to 
 which the radius-rod Gc, connected to the strap at c, should be fixed, and the radiijs of the circle will 
 be the length of the rod. If the point b be taken exactly in the middle of the strap, the length of the 
 radius-rod G c will be equal to the portion of the beam a F. 
 
 3021. 
 
 Fig. 3020 is another plan of a parallel motion sometimes used : the method of finding the length of 
 the rod D c and position of the point !> is the very same as that described in Fig. 3019, viz., by putting 
 the beam in its three positions, and marking the places of the points ccc of the strap, while the point b 
 to which the piston-rod is fixed is kept in the same straight line: the radius D c of the circle passing 
 through the points ccc will be the length of the radius-rod, and the centre of the same circle the point 
 to which it should be fixed. 
 
 Fig. 3021 is a method of causing the piston-rod to describe a straight line, often adopted in forcing- 
 
464 
 
 PARALLEL MOTIONS. 
 
 pumps : the lever F lias the centre of motion at o in the up standard s, fixed upon the cover of the pump 
 1) is a cylindrical rod, also fixed to the top of the pump, and set quite parallel to the pump-rod R ; g 
 is a cross head attached to the top of the pump-rod, having a projecting arm h terminating in a socket/ 
 •which moves on the rod D ; the lever F is connected to the cross-head g by two straps, one of which 
 is shown at c ; upon moving the lever F it will be quite clear that the piston-rod R must move par- 
 allel to D. 
 
 Fig. 3022 is a drawing of a walking-beam for a twelve-horse engine, with parallel motion attached 
 The point B to which the inner strap is fixed, is very often taken exactly in the centre, betwixt A and c 
 and when that is the case, the length of the radius-rods is equal to the same distance, or, in other words, 
 equal to the fourth part of the whole length of beam. 
 
 When the inner strap is suspended from any other point than in the middle of the distance Ac, the 
 position of the centre and length of the rod ef would be found as described in Fig. 3019: keeping the 
 point a to which the piston-rod is attached always in the same straight line in which it ought to move, 
 and carefully marking the points assumed by the lower end of the strap/. 
 
 The point b to which the air-pump rod is fixed should be exactly in the middle of the strap, when the 
 beam is divided into four equal parts, which will also insure a parallel motion for the bucket of the 
 air-pump. 
 
 P 
 
 3024. 
 
 So.:' 
 
 Fig. 3023 is a mode of causing the piston-rod to describe a straight line by the use of the two friction- 
 wheels W W confined betwixt the guides G G ; this plan is often used in small engines, when the crank 
 to which the connecting-rod P is attached is immediately above the cylinder. 
 
 Fig. 3024 is a plan of parallel motion usually employed in marine engines ; the manner of finding the 
 length and position of the radius-rod g is precisely the same as in Fig. 3019 ; this motion is, in fact, the 
 common parallel motion modified to suit the circumstan- 
 ces in which it is placed. The length of the radius-bar 
 ef is easily found in practice, by supposing the piston-rod 
 to move in a right line, and finding three points through 
 which a point in the side-rod A, assumed at pleasure, 
 would pass, in the highest, middle, and lowest positions 
 of the piston-rod ; then a circular arc passing through 
 these points will give the radius and centre sought ; and 
 the point e assumed in the side-rod will be the point of 
 connection of the radius-bar. 
 
 Now, in order that the point P of connection of the side- 
 rod and piston-rod may describe a right line, the point / 
 must describe an arc of curvature sufficient to neutralize 
 the curvature which would be transmitted to it by the 
 travel of the side-lever; to determine this arc///, it is 
 only necessary to describe from the middle point of the 
 stroke, taken in the straight line e«e, a right line egf 
 equal in length to the length of the radius-bar, and per- 
 pendicular to it ; also the highest position of the radius- 
 bar forming the same angle with egf that the radius-bar 
 forms with that line in its lowest position ; then the three 
 points/// 1 being thus found, a circular arc drawn through 
 them will determine the fixed centre g, and the length of 
 the parallel bar g f 
 
 The length of the side-bar c from f to its connection 
 with the side-lever, must of course be equal in length to 
 the side-rod A, from ? to the point also of its connection 
 with the side-lever. These rods will remain during the 
 working of the engine parallel to each other, and conse- 
 quently the radius-rod will continue parallel to the axis 
 
 of the side-lever in all positions of the stroke. It must, however, be remarked, that the parallelism is 
 not absolutely correct, but is true only within certain though narrow limits, giving an approximation 
 sufficiently near for common practice. 
 
PENDULUM. 
 
 465 
 
 Fig. 3025 shows a form of parallel motion sometimes adopted in land-engines of the smaller class 
 It is susceptible of great accuracy, and admits of several modifications. 
 
 In this figure A is the cylinder of the engine, B the beam, supported on a rocking-bar having a mov- 
 able centre at D. The radius-bar has its fixed centre at a attached to the framing of the engine, and is 
 centred to the beam at a point c equidistant from the main centre/ and the point of attachment to the 
 piston-rod. Flow, the radius-rod being equal to half the radius of the beam, and the radius-bar having 
 a fixed centre at a, the point c of the beam must of necessity describe the arc ccc during each stroke ol 
 the piston. Now, in describing this arc it is plain that the main centre /of the beam must describe 
 simultaneously an arc about the centre D upon which it is carried. But the radius / D being great in 
 comparison to radii/c and ac, the motion of the main centre may be supposed, without sensible error, 
 to be in a right line, as if it were free to slide in a horizontal groove. But the centre / being constrained 
 to move horizontally through a given space during a stroke of the piston, the end a of the beam will 
 travel horizontally through an equal space in the same direction, and will therefore, instead of describing 
 an arc about the centre f describe the chord a aa oi that arc, parallel to the chord of the arc ccc, which 
 is the thing wanted. 
 
 This motion and its modifications are founded on the principle that if the arc of a semicircle be made 
 to slide against a fixed point p, Fig. 3026, while one of its extremities x is constrained to move in a 
 straight line xp, the other extremity y will describe another straight line py at right angles to the 
 first. 
 
 To exhibit this principle in a practicable form, let in n be a rigid bar, having the end n guided in a 
 horizontal groove, in which it can slide freely, as represented in Fig. 3027 ; and let p q be also a rigid 
 bar jointed to the former at q, and having a fixed centre at p. Let this bar be half the length of the 
 bar m n , and let mq — nq\ it is then evident, from the principle stated above, that, as the groove at n 
 and the fixed centre at q control the motion of the bar m n, the end m is constrained to move in a straight 
 line mp r at right angles to p n, which is the condition to be fulfilled. 
 
 In Fig. 3025, instead of the slot at n the main centre is allowed to traverse a small arc, which, devi- 
 ating very little from a right line, fulfils the condition with considerable exactness. The same principle 
 may be applied in various ways. 
 
 P ARAMETER. In geometry, a constant straight line, belonging to each of the three conic sections 
 — otherwise called the latus rectum. In the parabola, the parameter is a third proportional to the 
 absciss and its corresponding ordinate ; in the ellipse and hyperbola, the parameter of a diameter is a 
 third proportional to that diameter and its conjugate. The term is also used in a general sense, to de- 
 note the constant quantity which enters into the equation of a curve. 
 
 PENDULUM. If any heavy body, suspended by an inflexible rod from a fixed point, be drawn aside 
 from the vertical position, and then let fall, it will descend in the arc of a circle of which the point of 
 suspension is the centre. On reaching the vertical position it will have acquired a velocity equal to 
 that which it would have acquired by falljng vertically through the versed sine of the arc it has de- 
 scribed, in consequence of which it will continue to move in the same arc until the whole velocity is de- 
 stroyed ; and if no other force than gravity acted, this would take place when the body reached a height 
 on the opposite side of the vertical equal to the height from which it fell. Having reached this height 
 it would again descend, and so continue to vibrate forever ; but in consequence of the friction of the 
 axis, and the resistance of the air, each successive excursion will be diminished, and the body soon be 
 orought to rest in the vertical position. A body thus suspended, and caused to vibrate, is called a 
 pendulum ; and the passage from the greatest distance from the vertical on the one side to the greatest 
 distance on the other is called an oscillation. 
 
 In order to investigate the circumstances of the motion, the body must be regarded as a gravitating 
 point, and the inflexible rod as devoid of weight. This is denominated the simple pendulum, and the 
 pioblem to be resolved is to determine the motion of a point constrained to move in a circular arc in 
 virtue of the accelerating force of terrestrial gravity. 
 
 Von. II.— 30 
 
4G6 
 
 PENDULUM. 
 
 According to the theory of falling bodies, (See Gravity,) the time t in 'which a body falls through th« 
 
 2s 
 
 space s, by the accelerating force of gravity, is given by the equation t — -f — . Let 2 s = /; then t ~- 
 
 l .9.1 
 
 J -■ But the time T, of the oscillation of a pendulum whose length is /, is T = tta/-; therefor* 
 
 9 \ 9 
 
 T : t : : t : 1 ; consequently the time of the oscillation of a pendulum is to the time that a heavy body 
 would fall freely by the force of gravity through half its length, as the circumference of a circle to its 
 diameter. 
 
 If we suppose the time to be expressed in seconds, and make T = 1, we shall have g = t? 1. Cap- 
 tain Kater found the length of the simple pendulum at London to be 39-13929 inches, and we know 
 that tt 2 = 9-8696 ; therefore g = 9-8696 X 39'1 39 = 386-29 inches, or g — 32-2 feet. It follows, there- 
 fore, that the space tlirough which a body falls freely at London in a second of time is 16-1 feet. 
 
 Compound pendulum. — The simple pendulum, as above defined, is only a theoretical abstraction , 
 for the oscillating body can neither be so small that it may be regarded as a mathematical point, nor 
 can the rod be entirely devoid of weight. When the body has a sensible magnitude, and the suspend- 
 ing-rod a sensible magnitude and weight as they must have in all actual constructions, the apparatus is 
 called a compound pendulum ; and instead of being supported by a single point it is supported by an 
 axis, or by a series of points situated in the same straight line. According to this definition, any heavy 
 body oscillating about an axis of suspension is a compound pendulum. 
 
 In every compound pendulum there is necessarily a certain point at which, if all the matter of the 
 pendulum were collected, the oscillations would be performed in exactly the same time. This point is 
 the centre of oscillation. (See Centre of Oscillation.) It is situated in the vertical plane passing 
 through the centre of gravity of the pendulum, and at a distance from the axis of suspension, (the axis 
 being always supposed horizontal,) which is determined by the following formula: Let dm be the ele- 
 ment of the mass of the compound pendulum, r its distance from the axis of rotation, and x the distance 
 of the centre of oscillation from the same axis ; then 
 
 x=j^r 1 dm-r ■ rdm\ 
 
 that is, the distance of the centre of oscillation from the axis of suspension is equal to the moment oi 
 inertia of the oscillating body divided by its moment of rotation. This value of x is the length of the 
 isochronous simple pendulum, and is what is always to be understood by the term length of a pendulum 
 
 The centre of oscillation possesses a very remarkable property, which was discovered by Huygens ; 
 namely, that if the body be suspended from this point, or a horizontal axis passing through it parallel 
 to the former axis of suspension, its oscillations will be performed in the same time as before ; in other 
 words, the axis of suspension and oscillation are interchangeable. This property furnishes an easy prac- 
 tical method of determining the centre of oscillation, and thence the length of a compound pendulum. 
 
 Applications of the pendulum. — The most important application that has been made of the pendulum 
 is to the measurement of time. 
 
 Compensation pendulum . — The value of the pendulum as a regulator of time-pieces depends on the 
 isoclironism of its oscillations ; which, in its turn, depends on the invariability of the distance between 
 the points of suspension and oscillation. But, as every known substance expands with heat and con- 
 tracts with cold, the length of the pendulum will vary with every alteration of temperature, and the rate 
 of the clock consequently undergo a corresponding change. To counteract this variation numerous con- 
 trivances have been employed. The principle is, however, the same in all ; and consists in combining two 
 substances, whose rates of expansion are unequal, in such a manner that the expansion of the one counter- 
 acts that of the other, and keeps the centre of oscillation of the compound body always at the same dis- 
 tance from the axis of suspension. A brief description of the two compensation pendulums in most 
 common use — the mercurial pendulum and the gridiron pendulum — will sufficiently explain the means 
 by which compensation is obtained. 
 
 Mercurial pendulum . — This was the invention of Mr. George Graham, a celebrated watchmaker, who 
 subjected it to the test of experiment in the year 1721. The rod of the pendulum is made of steel, and 
 may be either a flat bar or a cylinder. The bob or weight is formed by a cylindrical glass vessel, about 
 8 inches in length and 2 inches in diameter, which is filled with mercury to the depth of about 6 J inches. 
 The cylinder is supported and embraced by a stirrup, formed also of steel, through the top of which the 
 lower extremity of the rod passes, and to which it is firmly fixed by a nut and screw on the end of the 
 rod. Now the effect of an increase of temperature on this apparatus is evidently as follows : In the 
 first place, the rod expands, and the distance between the axis of suspension and the bottom of the stir- 
 rup is increased. In the second place, by the expansion of the mercury in the cylinder, its column is 
 lengthened, and the distance of its centre of gravity from the bottom of the stirrup consequently in- 
 creased. But, as the expansion of mercury is about sixteen times greater than that of steel, the height 
 of the mercurial column may be so adjusted by trial that the expansion of the rod and stirrup shall be 
 exactly compensated by that of the mercury, and the centre of oscillation of the whole suffer no change. 
 This pendulum is, perhaps, the most perfect of all compensators ; but, as its adjustments are attended 
 with considerable difficulty, it is seldom used excepting in astronomical observatories. 
 
 Gridiron pendulum . — This was contrived by Mr. Harrison, the inventor of the chronometer. It con- 
 sists of a frame of nine parallel bars of steel and brass, arranged as follows : The centre rod, of steel, is 
 fixed at the top to a cross-bar connecting the two middle brass rods, but slides freely through the twe 
 lower cross-bars, and bears the bob. The remaining rods are fastened to the cross-pieces at both ends, 
 and the uppermost cross-piece is attached to the axis of suspension. It is easy to see that the expan- 
 sion of the steel rods tends to lengthen the pendulum, while that of the brass rods tends to shorten it ; 
 consequently, if the two expansions exactly counteract each other, the length of the pendulum will re- 
 main unchanged. The relative lengths of the brass and steel bars are determined by the expansions oi 
 
PENS, STEEL. 
 
 467 
 
 til 3 two metals, which are found by experiment to be, in general, nearly as 100 to 61. If, then, the 
 lengths of all the five steel bars added together be 100 inches, the sum of the lengths of the four brass 
 bars ought to be 61 inches. When the compensation is found on trial not to be perfect, an adjustment 
 is made by shifting one or more of the cross-pieces higher on the bars. 
 
 Application of the pendulum to the determination of the relative force of gravity at different places . — 
 There are two methods of determining the relative intensity of gravity by means of the pendulum. Ac- 
 cording to the first, the absolute length of the simple pendulum which makes a certain number of oscil- 
 lations in a given time is accurately ascertained at each of the places, and the comparative force of 
 
 l> 
 
 gravity is then given by the formula g’ — -^-g. According to the other method, an invariable pendu- 
 
 lum is swung at the different places, and the number of its oscillations noted at each, when the relative 
 
 N' 2 
 
 gravity is given by the formula g' — — g. Each of these methods has been followed in the delicate 
 
 experiments which have been made for the purpose of determining the figure of the earth ; but though 
 the results of both appear to be nearly equal in point of accuracy, the latter method, on account of its 
 affording greater facilities in practice, is now generally adopted. See Watchmaking. 
 
 PENS, STEEL, manufacture of The manufactory, at Birmingham, of Messrs. Hinks, Wells, & Co., 
 a few years ago consisted of a small house on one side of the street. Now the establishment has 
 become an immense manufactory, giving employment to 664 hands, consuming 24 tons of steel per 
 week, turning out 35,000 gross of pens weekly, or 1,820,000 gross in a year. 
 
 The metal in its crude state . — This consists of the best quality of cast-steel, made from Swedish iron, 
 its granular structure dense and compact. It is in sheets 44 feet long by 18 inches wide, which sheets 
 are clipped across into lengths from If to 44 inches wide. These strips are packed into cast metal boxes, 
 and placed on what is technically called a muffle, or large stone oven, heated to a white heat ; there the 
 process of annealing takes place. After twelve hours of this roasting, the strips are placed in revolving 
 barrels, where, by the friction of metallic particles, the scales caused by the annealing and the rough 
 edges are removed. They are now ready for the rolling-mill. The rollers consist of metal cylinders 
 revolving upon each other. A man and boy attend at each. The first introduces the strip of steel 
 between the opposing surfaces, and the boy pulls it out considerably attenuated. From the first pair 
 of rollers it passes through several others, until it finally assumes the requisite tenuity. Such is the 
 pressure employed, that the steel, in passing through, becomes hotter than it is sometimes convenient 
 for unpractised hands to touch. The strip of] steel is now precisely the thickness of a pen, is quite flex- 
 ible, and has increased in length from 18 inches to 4-4 feet. 
 
 It is now ready for the “ cutting-out room,” where the pen first begins to assume a form. Along this 
 room a number of women are seated at benches, cutting out, by the aid of hand-presses, the future pen 
 from the ribbon of steel. This is done with great rapidity, the average product of a good hand being 
 200 gross, or 28,800, per day of ten hours. Two pens are cut out of the width of the steel — the broad 
 part to form the tube, and the points so cutting into each other as to leave the least possible amount of 
 waste. 
 
 From this room the blanks are taken to be pierced. The flat blanks are placed separately on a 
 steel die, and, by a half-circular action of a lever turning an upright screw, a fine tool is pressed 
 upon the steel, and forms the delicate centre perforation, and the side slits which give flexibility to 
 the pen. 
 
 All this time the metal is soft, bending in the fingers like a piece of lead. It becomes necessary, 
 however, that it should be„rendered still softer. The pens are consequently placed in the heated oven, 
 and a second time annealed. Proceeding with these softened pens to the “ marking-room upon each 
 side and down the middle of the room are arranged a multitude of young women at work, each oi 
 whom raises a weight by the action of the foot, and suddenly allows it to fall on the pen. The rapidity 
 of this process is equal to that of cutting out the blanks, each girl marking many thousands of pens in 
 the day. When it leaves the hand of this operator, the back of the pen is stamped either with the 
 name of a retail dealer at home or abroad, a national emblem, die., according to the fashion. 
 
 The next process is the raising. Until now the pen is flat; and by being placed in a groove, and a 
 convex tool dropped upon it, forcing it into the groove, it is bent into a tube of the required shape. 
 
 Upon the perfection of the slit of course depends the value of the pen. Those who recollect the diffi- 
 culty experienced in getting a perfect slit in a quill pen, can understand how much less easy it is to 
 prevent the gaping of a metallic substance. The first preparatory process after the pens leave the 
 raising-room, is to return them once more to the mufHe, into which they are placed in small iron boxes 
 with Uds, and heated to a white heat. They are then drawn out and suddenly thrown into a large tank 
 of oil, where, by the chemical action of the liquid on the steel, the pens attain a brittleness that makes 
 them crumble to pieces when pressed between the fingers. After being cleaned from the oil they are 
 tempered, or brought back to the condition of softness and elasticity which they are henceforth to retain. 
 This is done by placing them in a cylindrical vessel, open at one end and turned over a tire, somewhat 
 after the fashion in which coffee is roasted. The action of the heat gradually changes the color of the 
 pens, first from a dull gray to a pale straw-color, next to a brown or bronze, and then to blue. 
 
 Still the pens are rough, and covered with small metallic particles. To remove this roughness, they 
 are placed in large tin cans, with a small quantity of sawdust, itc. These cans lie horizontally on a 
 wooden frame, and are made to revolve by steam-power, the pens rubbing against each other, and so 
 cleansing themselves. From this process of scouring , they are taken to the grinding-room.” Each 
 individual pen of the 262,080,000 which are annually turned out of this establishment undergoes the 
 process of grinding, which employs one-fourth of the entire number of hands engaged in the manu- 
 factory. W e have previously referred to the difficulty of getting a close slit in a quill pen. The 
 grinding serves the same purpose as the scraping the back of the quill did, as, by weakening a certain 
 
468 
 
 PERCUSSION-CAP MACHINE. 
 
 part of the metal, the point where the slit is made has a tendency to cohere, and so to form * 
 good pen. The pen is simply caught up by a pair of nippers, and held on a revolving bob, and so 
 ground. 
 
 The pens are now taken to the “ slitting-room.” This work is very light, for the pen is simply placed 
 on a press, and the handle being pulled, a sharp steel tool descends, and the pens are perfect. To 
 secure uniformity of quality, the pens are now looked over, by the points being pressed against a small 
 piece of bone placed on the thumb, and they are then thrown into heaps according to their quality of 
 good, bad, or indifferent. They are next varnished with a solution of gum, and are ready for atfixin? to 
 cards, or boxing, the latter mode of packing being almost universally adopted. 
 
 PERCUSSION. The centre of percussion is that point in a body revolving about an axis, at which, 
 if it struck an immovable obstacle, all its motion would be destroyed, or it would not incline either way 
 
 When an oscillating body vibrates with a given angular velocity, and strikes an obstacle, the effect 
 of the impact will be the greatest if it be made at the centre of percussion. 
 
 For, in this case, the obstacle receives the whole revolving motion of the body ; whereas, if the 
 blow be struck in any other point, a part of the motion will be employed in endeavoring to continue the 
 rotation. 
 
 If a body revolving on an axis strike an immovable obstacle at the centre of percussion, the point of 
 suspension will not be affected by the stroke. 
 
 PERCUSSION-CAP MACHINE, by Richard M. Bouton, of West Troy, New York. Fig. 3028 is 
 a front elevation; Fig. 3029, a right-hand profile elevation; Fig. 3030, four views of the transfer appa- 
 ratus, full size; Fig. 3031, the star-punch, with its picker, lower die, and thimble, all in section, full 
 size; Fig. 3032, the forming-punch and its die, in section, full size. 
 
 This machine consists essentially of two vertical punches, of which one cuts the star or blank, of 
 which the capsule is formed ; and the other forms the capsule by compression. These punches are at 
 their upper ends attached each to its respective arm on the same end of a double-headed lever, and 
 consequently both move at the same time ; and their operations are combined in effect by mechanism, 
 which transfers the star or blank from its punch to the forming-punch. To enable other practical me- 
 chanics to make and use my invention, I will proceed to describe its construction and operation. 
 
 A A, Ac., is the bed-plate, on which are fixed the frame of the machine and a pedestal, (not shown,) 
 which supports the right-hand end of the branch arbor C C, to which the power is applied. 
 
 B B, Ac., the frame of the machine, to which most of the working parts are attached. 
 
 L L, main lever, or double-headed lever, by which the punches are worked. Its long arm is, by a 
 connecting-rod and crank-pin, connected with the crank of the crank-arbor, h h are the short arms or 
 double head, to which are attached 
 
 R R', the two runners which carry the punches. 1 2 3 4 are the guides through which the runners 
 work. These runners may be operated by cams on an arbor passing over their upper ends or through 
 openings or offsets in the middle of their lengths. In this case the main lever and crank-arbor can be 
 dispensed with, and power be applied to the cam-arbor direct. 
 
 Iv K K, bench or shelf, projecting from the frame, on which are the die-beds F and F'. The right 
 hand half of this bench is elevated higher than the left-hand half of its length, in order that the star- 
 die on this part shall be higher than the forming-die on the left-hand half, and that the groove or way of 
 the director d d , Ac., which rests on this part, may be on a level with the face of the forming-die V. 
 
 F, die-bed of the star-punch. This is a square above the bench, and has a round shank passing down 
 into the bench, to which it is fixed by a screw from below. The star-die U has a round hollow shank 
 passing down into this bed, and is supported by a flanch X, Fig. 3031, at its upper end, resting on the 
 top of the die-bed. Within this shank of the star-die is a conical steel tube or thimble vv, Fig. 3031, 
 the lower end of which rests on the director and transfer slide, it reaching up to the cutting part of the 
 star-die. Its internal diameter is exactly equal to the diameter of the star or blank, which, falling 
 from the star-punch through it, is conducted to its proper position on the transfer. The star-punch, 
 with its picker, die, and thimble, are seen in section, full size, in Fig. 3031. 
 
 F', die-bed of the forming-punch. This is round and has a shank passing down through the bench, 
 to which it is fixed by a screw-nut on it below ; through the axis of this shank, and of the forming-die, 
 operates the elevator e. In a socket in this bed stands 
 
 V', the forming-die ; its upper surface is on a level with the way of the director d T'". This die is seen 
 in section, full size, in Fig. 3032, Y, as is also 
 
 Z Z', the forming-punch, which is compound, having an outer shell z, which planishes the flanch of the 
 capsule, and an internal or .centre punch Z', which forms the inside. This centre punch has a shank 
 passing up through the axis of the shell z, and is secured by a cross-key near the bottom, or by a coun- 
 tersunk nut at the upper end. This arrangement, by equalizing the thickness of the several parts, 
 allows a better temper, and consequently insures a more perfect operation and more durability. 
 
 T T'T', Fig. 3030, three views of the transfer, full size. T, slide, with lower face upward ; b, the boss 
 in which the pin i of the connecting-link l works. T' shows the plate and link in profile, and T" shows it 
 in working position with the connecting-link l attached to it, slides in the way (groove) of the director 
 d T"'. The transfer is operated by the lever or arm t i applied to the pintle i. It will be seen in Figs 
 3028 and 3029 that the director d T", Ac., with its transfer, pass through the bed F of the star-die; it 
 passes immediately below the star-die and its thimble, in order that the star may fall from its punch 
 through the thimble upon the transfer slide. 
 
 IT, Fig. 3031, the star-punch. This punch, with its picker, and the star-die, with its included 
 thimble are shown, full size, in vertical section, where q is the picker with its spiral spring above 
 it, and v v the thimble. The office of the picker is to prevent the adhesion of the stars to the face of 
 the punch. 
 
 C C, crank-arbor, to which the power is applied. On this is the collar and flanch D D, on which is 
 the feed-cam c, which operates the feed-lever f, and through the double hands P P, works the ratchets 
 
PERCUSSION-CAP MACHINE. 
 
 469 
 
 r r of the feed-rollers. Oil the opposite face of this collar is the cam c of the elevator lever E E, which, 
 through the rocking-arbor E' and arm a, raises the elevator e, lifting the capsule out of the forming-die ; 
 it is returned by the spiral spring s ss, Fig. 3028. E" is the anvil on which the elevator rests while a 
 capsule is being pressed ; it has an adjusting screw and nut. 
 
 G G, &c., cam lever of the transfer apparatus. It is fast on its axis J J, which works in the bracket 
 II H, <fcc., and is operated by the cylinder cam I on the crank-arbor, and returned by a spiral spring on 
 the axis J J. The lever 1 1 is free on the axis J J, but is constrained to move in concert with G, by 
 means of a spring, which allows it, together with the transfer, to yield to extraordinary resistance, while 
 the cam and fast lever pursue their way thus preventing injury to the machine. 
 
470 
 
 PERCUSSION-CAP MACHINE. 
 
 u is the gage, a cap of steel over the head of the forming-die, with semicircular notch in iis edge 
 against which the star is driven by the transfer and held concentric with the forming-die until seized bj 
 the forming-punch. 
 
 y y, the driver, a slender lever suspended by its upper end thrown forward by a spring y ; its lower 
 pnd is bent forward over the face of the forming-die, somewhat in form of a human foot and leg, Fig 
 
 8029. It is operated by a pin in the runner R' pressing against a tumbler, and holding it behind the 
 punch while a capsule is being formed, and releasing it instantly when the capsule is raised by the ele- 
 vator above the gage u. 
 
 n n, feed-rollers. There is a similar pair behind the punch to continue the progress of the ribbon afte* 
 
PERCUSSION-CAP CHARGING MACHINE 
 
 471 
 
 it has passed the front rollers, m is a lever to open and close the feed-rollers. All these parts arc 
 attached to a movable plate K, covering the front of the bench K, Ac. 
 
 Operation . — The material is cut in ribbons of such width as will admit of two rows of blanks or star- 
 being cut from each lengthwise; but the machine may be so constructed without departing from its 
 principles as to work from ribbons of any width. 
 
 One end of a ribbon being inserted between the feed-rollers n n, is by them drawn in, while a row ot 
 stars is successively cut near one edge throughout its length. When not enough surface remains for 
 another star or trigger, (not shown,) which has ridden upon its surface, drops off at the end, and by 
 mechanical connections stops the machine. Each star, as soon as cut, is projected by the picker q down 
 through the thimble v v, Fig. 3031, upon the face of the transfer, which 
 at this instant is holding a previous star against the gage u under the 
 forming-punch z ' ; on its return its operating end passes beyond the 
 thimble, which consequently sweeps the star deposited in it off of 
 the transfer into the way of the director, and the next stroke of the 
 transfer drives it to the forming-die while another star is being 
 dropped from the star-punch, so that only one star is in the thimble 
 at the same time. 
 
 While the forming-punch rises out of its die, the elevator c raises 
 the capsule after it above the gage, whence the driver y kicks it into 
 the mouth of a receiving-tube, (not shown,) which conveys it to the 
 reservoir. The elevator now sinks, the driver retires behind the 
 punch, and all is clear for another star. 
 
 The machine is a self-operator, and delivers the capsules with a 
 high finish and in a state proper to receive the priming. 
 
 I do not claim as my invention punches and dies for making per- 
 cussion-caps, as these have been so employed in various ways ; but 
 what I do claim as my invention, and desire to secure by Letters 
 Patent, is the combination and arrangement of the mechanism above 
 described for producing the combined operations herein fully set forth, 
 of feeding the metallic ribbon to the star-die U', punching the blank 
 from the ribbon, transferring the blank to the forming-die V by the transferring apparatus TT'T"T" 
 punching the blank into the forming-die V and forming it into a cap, and discharging the same from the 
 die by the elevator e, and kicking the cap in a finished state from the die-bed by the driver Y. All 
 of said operations being performed successively at every revolution of the crank and cam-arbor c, to 
 which the propelling power is applied, substantially as above described. 
 
 2d. I also claim the transferring apparatus constructed substantially as described, in combination 
 with the punches. 
 
 PERCUSSION CAPS, MACHINE FOR CHARGING— M. W. Fisher’s. In Fig. 3033 , the mag- 
 azine. or hopper, in which the fulminating composition is placed, is supported by the tremulous base 
 a rising from the platform, and projecting over the edge of the horizontal ratchet-wheel A, in the 
 Beties of vertical apertures near the periphery of which the caps are placed to receive then - charge 
 
 3031. 3032. 
 
472 
 
 PERCUSSION-CAP CHARGING MACHINE. 
 
 The lower portion of the magazine is funnel-shaped, and opens into a rectangular tube in which the 
 charge E is accurately fitted, and freely slides back and forth. 
 
 A circular aperture is formied in the under side of the tube at the distance of an inch or two from 
 the magazine, exactly corresponding in size with the aperture at the bottom of the magazine, ana 
 with the aperture in the charge E. 
 
 A reciprocating movement being imparted to the charger, the aperture in the same, in passing back 
 and forth under the outlet of the magazine, will receive the charge of composition for a cap and will dis- 
 charge the same as the charger is drawn back into a cap brought immediately under the aperture, by 
 the movement of the wheel A upon its axis, in the manner hereinafter set forth. 
 
 N is the main-shaft, from which all parts of the machine receive motion. Motion is imparted to tlio 
 
 ratchet-wheel A and to the charger E by means of the vibrating lever C, suspended by and vibrating 
 on the arm G' projecting from the end of the machine, the cam 13 on the main-shaft, the cord t con- 
 nected to the upper end of C and passing to the rear over a loose pulley on the axle S', and sus- 
 pending the weight T' at its extremity. A vertical arm F rises from the front end of the charger E, 
 having a vertical slot near its upper end, through which passes an adjustable pin projecting from the 
 lever 0 by which it is operated. A pivot at the lower extremity of the lever C takes into an aper- 
 ture in the ratchet D, which communicates motion to the wheel A. The ratchet D works in the 
 guiding-box t , and is kept in contact with the teeth on the periphery of A by the spring s'. 
 
 The cam B is of such a form that it will force back the upper end of the lever C, and thereby will 
 carry forwards the ratchet D and the charger E, and move the periphery of the wheel A the distance 
 
PERCUSSION-CAP CHARGING MACHINE. 
 
 473 
 
 of the length of a tooth, and in that position will retain them during one-half of the revolution of the 
 main-shaft. During the other half of the revolution of the main-shaft, the periphery of the cam B 
 ceases to press back the upper end of C, and receding towards the shaft permits the weight T' U 
 draw forwards the upper end of C and carry back the ratchet D and the charger E. The charger, iu 
 passing back to its starting-place, deposits a charge in a cap, as before described. In this manner the 
 metallic caps placed in the series of apertures in the ratchet-wheel A receive their respective charges. 
 The apertures in A correspond in number with the ratchet-teeth on its periphery, and are so arranged 
 that each forward movement of the ratchet D will place one of the apertures in A directly under the 
 aperture iu the tube, in which the charger E traverses back and forth, as before described. 
 
 'file composition is forced into the caps in the following manner : On the opposite side of the wheel 
 A from the magazine two arms project from the standard A", which arms embrace journals at the 
 ends of a vertical tube R. The tube R serves as a guide and supporter to the shaft of the punch which 
 forces the composition into the caps. The shaft is composed of two cylindrical parts, which rotate with 
 and play freely up and down in the tube R. The respective parts of the shaft are connected to each 
 other and to the tube R. c c are arms secured to the inner ends of the respective parts of the shaft, 
 projecting out through vertical slots in the sides of the tube. The extremities of the arms c c are 
 connected to each other by the screw bolts or rods b b ; the blank portion of the bolts play freely in 
 the apertures in the arm c through which they pass. 
 
 A stiff and powerful helical spring embraces the middle portion of the tube R, the ends of which 
 bear against the arms cc within the bolts b b. A ring a loosely encircles the lower end of tube R; y 
 is a helical spring encircling the lower end of the tube between the lower supporting arm and the ring a, 
 which, acting against the lower arm c, forces up the punch-shaft. 
 
 A rotary motion is imparted to the tube It and the punch by means of the bevel-pinion, made fast to 
 the upper end of R, and working into a bevel cog-wheel 0 on the main-shaft. The punch is of such a 
 shape as to tit accurately into the caps : the wheel A in depth exactly corresponds with the depth of 
 the caps ; the wheel A revolves upon a journal g made fast to the platform, and passing up through 
 its centre. The edge of the wheel immediately under the punch passes over and slightly rests upon 
 the surface of a metallic block. 
 
 S is a cam on the main-shaft, immediately over the shaft of the punch ; the cam S is of such a form 
 that it will press down and have a continuous action upon the punch during about three-fourths of the 
 revolution of the main-shaft. The cam S strikes against the upper end of the punch-shaft, and forces 
 down the same, pressing the punch with great force into a cap, immediately after the cam B has acted 
 on the lever C, the ratchet D, the charger E, and wheel A, as before described ; during the time that 
 the punch is pressed upon the composition in a cap, four revolutions, more or less, are imparted to the 
 punch by means of the guiding-tube R, the pinion P, and cog-wheel O, which perfects the solidification 
 of the composition, and gives it the requisite adhesion to the caps. 
 
 During the action of the punch the ratchet D and the charger E are drawn back by the lever C and 
 weight T', and immediately thereafter the form of the cam S allows the sjjring y, on the lower portion 
 of R, to elevate the punch out of the cap, and retain it in an elevated position while the cam B and 
 lever C again operate upon the ratchet D, charger E, and wheel A, as before described. It will be 
 perceived that the pressure exerted upon the upper portion of the punch-shaft is communicated to 
 the lower portion of the same and to the punch through the medium of the spring. The object of this 
 arrangement is to give an elastic bearing of the punch upon the composition in the cap, so that should 
 it explode from any cause the punch can yield and give back, and no injury will be done to the ma- 
 chine or attendant. 
 
 The cam T, on the main-shaft, is placed immediately over and operates upon the rod U as follows . 
 the cam T is of such a form as to cause the rod U to descend simultaneously with the punch, forcing 
 the gagged under surface of an arm upon the flanch of the cap, which retains the same and prevents 
 the cap from turning while the punch is operating : the cam T also retains the arm upon the flanch of 
 the cap till the punch is elevated, and then allows the retaining arm to be elevated by the spring 
 encircling U, to allow motion to be imparted to the wheel. 
 
 The caps are thrown out of the apertures in the wheel A after the operation of charging before 
 described, by the following described arrangement of parts, viz. : A cap horizontal tilting-lever is jointed 
 to a fulcrum standard, the extremity of which farthest from its fulcrum joint terminates in an 'upright 
 punch ; the opposite end of it supports the vertical rod X, which passes up through guiding apertures 
 in arms projecting from the standard AT A spring y acts against the under side of the shortest portion 
 of the lever and sustains the rod X. W is a wheel on the main-shaft, from the periphery of which 
 projects the tilting-tooth e ; as the main-shaft is revolved the tooth e will strike against the top of the 
 rod X and cause it to tilt the lever at the moment when the wheel A is stationary ; the tilting ot 
 the lever brings the punch against the bottom of a cap, and throws it out of its aperture in the wheel ; 
 as the cap is thrown upwards the spring R' gives it a lateral direction, and conducts it into the funnel Q’ 
 open at the side, to which a tube may be connected to convey the caps to a drawer, or other suitable 
 receptacle. 
 
 The metallic caps may be placed in the apertures in the wheel A by hand, or by the arrangement 
 of the following described parts, viz. : I” is a hopper in which the caps are placed preparatory to their 
 being deposited in the apertures in A by machinery ; the caps fall from the vibrating shoe, at the 
 base of the hopper, into an inclined vibrating groove — the tubular portion of the caps passing into the 
 groove, and the flanehes resting upon the sides of the same. The periphery of the rotating brush H' 
 comes so nearly in contact with the sides of the groove as to prevent the caps from passing the same 
 unless their tubes are inserted in the groove. The inclined groove is secured by a pivot at its lower 
 end, and its upper end slides freely on a supporting bar. The shoe and the inclined groove are 
 vibrated by means of a connection with the ratchet teeth on the axle of the brush H' by any usual or 
 suitable contrivance. As the groove is vibrated, the caps are carried down the steepest portion of the 
 
474 
 
 PERPETUAL MOTION. 
 
 same ; the feeding-hand on the front end of the arm I is then placed upon them, and draws their 
 down the groove until the foremost one is caught between the scolloped edged wheels n n, located on 
 each side of and projecting into the groove. The concavities in the peripheries of n n are arcs cor- 
 responding with the tubes of the caps, and embrace nearly their entire circumference when the caps 
 are drawn between them. One of the wheels n plays freely on its axis ; the points radiating from the 
 other wheel n are operated upon by a retaining spring. The spring partially retains the wheel n, on 
 which it acts. As the caps are drawn down the groove, should the foremost one strike against a 
 ladiating point of the loose wheel n, it will revolve the same sufficiently to bring the cap between 
 opposite concavities of both wheels. The elastic feeding-finger, connected to the front end of the 
 arm J, is so operated that it is placed in a cap while it (the cap) is retained between the wheels n n, 
 and draw's it forwards and deposits it in an aperture in the wheel A. As the cap is drawn from 
 between the wheels nn it causes a partial revolution of the wheels ; the spring passes over a radiating 
 point in one of the wheels, and, striking on the next point in succession, retains the wheel in the 
 proper position for the reception of another cap. 
 
 The feeding-hand on the front end of the arm I has a soft face that rests but slightly upon the 
 flanches of the caps ; the front end of the arm I, when the hand is acting upon the caps, rests upon 
 the roller which traverses upon the edges of the groove. The feeding-finger passes through an aper- 
 ture and is secured to the spring-plate projecting from the under side of the front end of the arm J ; it 
 is steadied and kept in a vertical position by passing loosely through the plate projecting from the 
 upper side of the front end of J, and to give additional elasticity to the finger it is inclosed in a 
 helical spring. The arms I and J are jointed to and receive motion from the upright vibrating 
 levers I'J' ; the levers I' J' are jointed to and suspended by the curved standard K; the standard K 
 rises from the rear side of the platform, curves forwards over the centre of wheel A, and descends 
 vertically to the top of the axle g, to which it is connected. To the upper ends of the levers I' J' the 
 cords s s are connected, which pass to the rear over loose pulleys on the axle S', and suspend the weights 
 LT U' at their extremities : causing the upper end of I' to bear against the cam L, and the upper end 
 of J' to bear against the cam M on the main-shaft. 
 
 II is a vertical vibrating-lever, placed in the guiding-box u', and working on a joint-pin passing through 
 the sides of the same. 
 
 Angular arms/ and g project from the upper portion of H ; the angular extremity of/ passes to the 
 right over the arms I J, the extremity of g passes to the right under the arms I J. G is a horizontal 
 vibrating-lever jointed to the standard e'. The end of G, to the right of the standard e', passes immedi- 
 ately in front of the lower cord of the lever H ; the opposite end of G turns at right angles to the rear, 
 and is brought directly opposite and in contact with the head of the ratchet D. 
 
 When the ratchet D is drawn back by the lever C, it vibrates the lever G, causing it to throw back 
 the upper end of H, and thereby to elevate the front ends of the arms I J by the arm g at the moment 
 that the arms I J are elevated. The form and position of the cams L M permit the weights U' U' to 
 draw the upper ends of the levers I'J' to the rear, and carry the arms I J forwards ; the moment the 
 ratchet D is carried forwards again, the arms I J descend, placing the hand h upon the flanches of the 
 caps in the groove P', and the finger k in the cap held between the concavities of the wheels n n, as 
 before described. As soon as the arms I J descend, the cams LM commence acting upon the levers 
 I' J' and arms I J, causing the hand to carry forward the caps in the groove, and the finger to place a cap 
 in an aperture in the wheel A, as before described. The moment after the finger has deposited a cap 
 in an aperture in A, the arms I J are again elevated and carried to the front in the manner before de- 
 scribed. 
 
 The rotating brush H' is driven by the band passing around a pulley on the main-shaft N. The 
 rotating brush in the rear portion of the machine acts upon the upper surface of the wheel A near its 
 periphery, for the purpose of removing any of the percussion composition that may chance to be deposited 
 upon the wheel or flanches of the caps. This brush is driven by a band passing around a pulley on the 
 main-shaft. 
 
 PERPETUAL MOTION. In mechanics, a machine which, when set in motion, would continue to 
 move forever, or, at least, until destroyed by the friction of its parts, without the aid of any exterior 
 cause. The discovery of the perpetual motion has always been a celebrated problem in mechanics, on 
 which many ingenious, though in general ill-instructed, persons have consumed their time ; but all the 
 labor bestowed on it has proved abortive. In fact, the impossibility of its existence has been fully de 
 monstrated from the known laws of matter. 
 
 In speaking of the perpetual motion, it is to be understood that from among the forces by which 
 motion may be produced we are to exclude not only air and water, but other natural agents, as heat, 
 atmospheric changes, <tc. The only admissible agents are the inertia of matter, and its attractive 
 forces, which may all be considered of the same kind as gravitation. 
 
 It is an admitted principle in philosophy that action and reaction are equal, and that, when motion is 
 communicated from one body to another, the first loses just as much as is gained by the second. But 
 every moving body is continually retarded by two passive forces, the resistance of the air and friction 
 In order, therefore, that motion may be continued without diminution, one of two things is necessary — 
 either that it be maintained by an exterior force, (in which case it would cease to be what we under- 
 stand by a perpetual motion,) or that the resistance of the air and friction be annihilated, which is 
 physically impossible. The motion cannot be perpetuated till these retarding forces are compensated, 
 and they can only be compensated by an exterior force ; for the force communicated to any body can- 
 not be greater than the generating force, and this is only sufficient to continue the same quantity of 
 motion when there is no resistance. To find the perpetual motion is, therefore, a proposition equivalent 
 to this — to find a force (either an attractive force like that of gravitation or magnetism, or an elastic 
 force, that of a spring, for example) greater than itself 
 
 But it may be argued that, by some arrangement or combination of mechanical powers, a force may 
 
PILE-DRIVER. 
 
 475 
 
 oe gained equal to that which is lost in overcoming friction and atmospheric resistance. This motion 
 at first mention appears plausible, and is, in feet, that by which most spectators have been led astray. 
 It is, however, entirely erroneous ; for by no multiplication of forces or powers by mechanical agents 
 can the quantity of motion be increased. Whatever is gained in power is lost in time ; the quantity ol 
 motion transmitted by the machine remains unaltered. 
 
 PERSIAN WHEEL. In mechanics, a contrivance for raising water to some height above the level 
 of a stream. In the rim of a wheel turned by the stream a number of strong pins are fixed, from 
 which buckets are suspended. As the wheel turns, the buckets on one side go down into the stream, 
 where they are filled, and return up full on the other side till they reach the top. Here an obstacle is 
 placed in such a position that the buckets successively strike against it and are overset, and the water 
 emptied into a trough. As the water can never be raised by this means higher than the diameter of 
 the wheel, it is obvious that this rude machine is capable of only a very limited application. Sometimes 
 the wheel is niade to raise the water only to the height of the axis. In this case, instead of buckets, 
 tlie spokes are made hollow, and bent into such a form that when they dip into the water it runs into 
 them, and is thus conveyed to a box on the axle, whence it is emptied into a cistern. Such wheels are 
 in common use on the banks of the Nile, and elsewhere. 
 
 PHOTOGRAPHY. Photography, or sun-painting, is divided, according to the methods used to pro- 
 duce the picture, viz. — Daguerreotype, Calotypc, Chrysotype, Cyanotype, Chromotype, JSnergiatype, An- 
 thotype, and Amphitypc. 
 
 The principal instrument used in the Daguerreotype process is the camera obscura, and the images 
 from the lenses are thrown on prepared metal or other surfaces and fixed. The processes for the reten- 
 tion of the picture belong rather to chemical than mechanical science. This art is frequently employed 
 by mechanics and architects in making copies of drawings. See Cyclopedia of Drawing. 
 
 PHOTOMETER. An instrument for measuring the intensity of light, or of illumination. 
 
 PILE-DRIVER — Nasmyth's patent steam. This is a machine of great power, and one destined un- 
 doubtedly to take a prominent place among the improvements of the age. 
 
 Fig. 3034 is a front elevation of the entire machine, shown in full operation driving a pile. 
 
 Fig. 3035 is a corresponding general side elevation. 
 
 Fig. 3036 is a general sectional plan of the machine. 
 
 Fig. 3037 is a transverse section of the stage or platform, taken on the line 1 — 2, in Fig. 3036. 
 
 Fig. 3038, an enlarged elevation of the steam-chest and safety-valve geer. 
 
 Fig. 3039, a section corresponding to the above. 
 
 Fig. 3040 is an enlarged section of one of the joints of the flexible steam-pipes, for conveying steam 
 to the hammer-cylinder. 
 
 Fig. 3041, a plan corresponding to the above. 
 
 Fig. 3042, a sectional elevation of the hammer-cylinder and pile-case with all their appendages. In 
 this view the hammer is supposed to have just effected a blow upon the head of the pile, and the vari- 
 ous parts of the valve-geer are represented in the positions they occupy at the commencement of a fresh 
 stroke. 
 
 Fig. 3043, a front view of the hammer-cylinder and pile-case, witli their various attachments. 
 
 Fig. 3044, a sectional elevation of the same parts as are represented in Fig. 3042, with the driving 
 apparatus and valve-geer shown in the positions they occupy when the hammer is about to fall. 
 
 Figs. 3045 and 3046, enlarged views of the trigger and parallel motion of the valve-geer detached. 
 These views are drawn to a scale of twice the size of the other figures. 
 
 Fig. 3047 is a section of the hammer-block and hammer. 
 
 Fig. 3048 is a sectional plan of the pile-case, taken on the line 3 — 4, in Fig. 3043. 
 
 Fig. 3049, a sectional plan of the pile-case and hammer-block, taken on the line 5 — 6, in Fig. 3042. 
 
 General description . — There are two important features of novelty .which serve to distinguish the 
 datent Steam Pile-Driving Engine from all such as had previously been employed for the same pur- 
 pose. These consist : First, in the direct manner in which the steam is employed as the agent by which 
 the block of iron which strikes the head of the pile is raised to the required height ; and, Secondly, in 
 the peculiar mode in which the pile, while being driven into the ground, is employed to support 
 that part of the apparatus which is directly concerned in driving or forcing it into the soil — the appara- 
 tus in question being so contrived that, as the pile penetrates into the ground, the superincumbent ma- 
 chinery shall follow down with it until it has reached the required depth. 
 
 By the peculiar arrangement referred to under the second head, we secure two most important prac- 
 tical advantages : First, the piles are guided throughout their entire course with the utmost accuracy 
 and precision, so that no one shall twist or swerve in the slightest degree from the general line, or from 
 the position in which it is set at the commencement of the driving process, this object being attained 
 without any sacrifice of power from the friction of bands, or other appliances usually employed for that 
 purpose ; and, Secondly, the entire dead weight of the driving apparatus is brought into effective action 
 to second and follow up the blow last inflicted upon the head of the pile. This last peculiarity of ac- 
 tion constitutes one of the most important features of the machine, and has contributed very materially 
 to the success which has attended its use. During the brief intervals between the blows, (70 to 80 per 
 minute,) the pile is urged continuously downward by the action of the force here adverted to, so that it 
 may be said to be in a state of constant motion from the commencement to the termination of the driv- 
 ing, and thus the power which would otherwise be wasted in overcoming its inertia is profitably ex- 
 pended in forcing it further into the soil. 
 
 The basis or foundation on which the entire machine is erected, consists of a strong wooden stage oi 
 platform A A, firmly framed together and strengthened by diagonal timbers, and wrought-iron corner- 
 pieces, the whole being further secured by the massive cast-iron brackets B B, at each angle of the plat- 
 form, in which the locomotive wheels aaaa are fitted to work upon rails disposed parallel and close 
 to the line of piling on which the machine is destined to operate. The stage is made of sufficient dimen 
 
476 
 
 PILE-DRIVER. 
 
 sions and weight to give the requisite stability and firmness to the entire structure, and to afford room 
 for the steam-boiler, the workmen, and all that is necessary for the accomplishment of the proposed 
 object. The great vertical guide-pole C C, on which the driving apparatus slides, is securely bolted tc 
 one side of the platform, the boiler being situated towards the opposite side, to counterbalance tlic 
 weight of the former, and to afford an abutment for the diagonal timber supports D D, firmly bound to 
 both by plates of iron and numerous bolts; the entire frame work of the machine is further secured by 
 the four adjustable tie-rods or stays bbbb, attached to the four corners of the stage and to the top of 
 
 the upright. This latter is surmounted by a cast-iron socket-frame, supporting the brackets E E, which 
 carry a chain-pulley, over which works the great chain c c, one end of which is passed round a barrel 
 worked by a small steam-engine, as will be hereafter described, while the other end is attached to, and 
 sustains the weight of, the pile-driving apparatus. 
 
 This consists of a steam-cylinder F, with all the necessary appendages of piston, valves, ifcc., as will 
 be more particularly specified below ; the lower flange of the cylinder is firmly bolted to the pile-cane 
 
PILE-DRIVER. 
 
 477 
 
 G G, which is a species of rectangular box of a square section, constructed of plates of wrought-ircn, 
 strongly framed together in the manner indicated in the detail views. The interior surfaces of the pile- 
 case serve to guide the hammer-block in its vertical motion, and it is itself guided along the great up- 
 right C 0, by the pieces del , which are fitted to embrace the projecting slips of iron c e, bolted to the 
 front of the upright throughout its entire length. The lower end of the pile-case is open, to admit the 
 head of the pile, and is furnished with cast-iron jaws or resting-pieces// (see Figs. 3042 and 3044.) 
 bolted to its interior surfaces ; these are so formed as to rest upon the shoulders ot the pile H, which, 
 if we suppose the great chain-barrel to be left free to revolve, thus becomes the sole support for the 
 weight of the whole mass of the driving apparatus. By these arrangements it will be seen that as the 
 pile is, by successive steps, forced into the ground by the action of the hammer, (the chain-barrel being 
 thrown out of geer with its driving apparatus during the process,) the pile-case with all its appendages, 
 weighing about three tons, is left at perfect liberty to bear upon the shoulders of the pile, and follow 
 down along with it, while at the same time, and by the same means, the pile itself is guided into a 
 strictly vertical and true course. 
 
 3030. 
 
 The driving apparatus consists simply of a modification of his steam-hammer, the action of the vari- 
 ous parts being in all respects identical, though the whole is movable, as above described, instead of 
 being fixed. The steam necessary for its supply is generated in a boiler I, the construction of which is 
 very similar to that of the ordinary locomotive engine boiler. The steam-chest J surmounts the fire- 
 box, and is made of sufficient height to prevent the influx of water into the steam-pipes, and the entire 
 boiler and steam-chest are covered externally with a coating of felt, and with strips of wood to prevent 
 the radiation of heat, and to give greater symmetry of appearance. On the cover of the steam-chest 
 (the internal construction of which is fully shown in Fig. 3039) is cast a small square box g , containing 
 suitable bearings for the safety-valve, which is loaded by a weight and combination of levers h h li, and 
 for the throttle or shut-off valve, commanded by the lever-handle and rod i i. The steam is conveyed 
 from the boiler to the valve-chest of the driving-cylinder, by a flexible steam-pipe K K, composed of 
 several lengths of wrought-iron tube, connected together by swivel joints of cast-iron jjj, the construc- 
 tion of which will be fully understood by reference to Figs. 3040 and 3041. This arrangement admits 
 of the steam-pipe accommodating itself, without any loss of steam from leakage, to every variety of 
 height or distance at which the driving cylinder may be from the boiler, from the commencement of 
 the process, when the apparatus is sitting aloft upon the shoulders of a tall pile, until it has arrived at 
 its lowest position, when the pile has penetrated the soil to the required depth. 
 
 The remaining part of the driving apparatus is identical in the principles of its action, and very sum- 
 
478 
 
 PILE-DRIVER. 
 
 lar in the details of its construction to those of the direct action steam-hammer. For fuller informatioc 
 on these points, see Steam-Hammer. 
 
 F is the steam-cylinder, within which the power necessary for raising the hammer to the required 
 elevation (three feet) is generated. 
 
 L, the steam-valve chest, bolted to the lower side of the cylinder, within which the valve k is fitted 
 to work upon a face cast with the cylinder. The steam, after having accomplished its work, is permit- 
 ted to escape into the atmosphere by an oblong aperture l, formed in the cylinder-face ; and, to obviate 
 the risk of accident from the piston rising too high, a number of small round holes m m are formed near 
 
 3044. 3043. 3042. 
 
 the top of the cylinder, so that the steam may blow out into the air wneu the piston nses above their 
 edges. It may here be remarked that the efficacy of the blows of the hammer, and the security from 
 damage to the parts of the machinery, are in this case, as in that of the steam forge-hammer, materially 
 augmented by the recoil of the air or steam inclosed above the piston. 
 
 M, the piston, -formed of wrouglit-iron, and fitted with a single packing-ring. 
 
 N the piston-rod, having a cylindrical boss or enlargement n , at its lower extremity, for the purpose 
 
PILE-DRIVER. 
 
 479 
 
 of affording means for securing a slightly elastic connection, by hard-wood washers, between the piston- 
 rod and hammer-block. 
 
 O, the hammer-block, consisting of a rectangular mass of cast-iron, weighing 30 cwt., adapted to slide 
 freely but without much play, within the pile-case G G. It is furnished with suitable recesses for the 
 securing of the hammer, piston-rod, &c., and for enabling it to rise clear of the cylinder stuffing-box ; 
 and at its upper extremity a recess in the form of a species of inclined plane o' o', is provided, for the 
 purpose of acting upon the valve-lever so as to permit the escape of the steam, after it has raised the 
 hammer to a sufficient height. 
 
 P, the hammer: a cylindrical block of cast-iron, formed with a slightly concave face, fitted into the 
 hammer-block, and fastened thereto by a wrought-iron key o, which at the same time serves to secure 
 the connection of the piston-rod. 
 
 Q, the latch-lever working in a recess in the hammer-block, (see Fig. 3049.) The action of this part 
 of the apparatus is fully described in the account of the steam-hammer. 
 
 p, a small solid piston working in a cylindrical part of the valve-chest, and attached to the valve by 
 a short connecting-rod. Its under surface is constantly .acted upon by the pressure of the steam within 
 the valve-chest, so as to cause the steam-valve to assume the position indicated in Fig. 3042, unless 
 counteracted by a superior force. 
 
 q, the valve-*spindle, produced downwards and working in suitable bearings, so as to bring it under 
 the action of the trigger at the termination of the stroke. 
 
 r, the valve-lever, working outside of the pile-case, but having a small friction-roller attached to its 
 inner end, and situated so as to come under the action of the inclined plane o' oo". 
 
 s, the trigger, the function of which is to keep the steam-valve in such a position as to prevent the 
 admission of steam into the cylinder during the descent of the hammer-block. 
 
 t, the parallel bar, against which the latch-lever acts at the termination of the stroke, for the purpose 
 of releasing the valve-spindle from the trigger, in order to allow the steam to be admitted for a fresh 
 stroke. 
 
 u u u, the parallel motion bell-cranks and connecting-rod of the disengaging apparatus. 
 
 v, a buffer-box for the purpose of restricting the travel of the valve to its proper amount, and of dead- 
 ening the shocks to which it is subjected. 
 
 The above enumeration, together with the explanations previously given, will convey a sufficiently 
 clear idea of the construction of the pile-driving apparatus, properly so called. We shall now proceed to 
 describe the mechanism by which the pile-case and its appendages are elevated to the top of the great 
 vertical guide-pole, and the means employed to render the whole machine locomotive. 
 
 The power requisite for these purposes is supplied by a small horizontal steam-engine It, situated 
 opposite to the great upright C, and under the boiler I, from which it derives its supply of steam. The 
 motion of this steam-engine is transferred to the axis of the great chain-barrel by means of a train of 
 spur-geering calculated to increase the power to the required extent. Two broad plates of wrought- 
 iron, extending across the entire platform, and bolted securely to its timbers, afford a sufficiently firm 
 foundation for the engine, and for the bearings of the various shafts in the train of wheels, which con- 
 sists of three pairs marked w, x , and y, the pinion of the first pair being fixed upon the crank-shaft of 
 the engine, and the wheel of the last upon the axis of the chain-barrel. The pinion y is fitted to slide 
 ongitudinally upon its shaft by means of a sunk feather, and is commanded by the lever-handle z so as 
 to enable the attendant in charge of the machine to throw it out of geer with the wheel upon the chain- 
 barrel shaft, when the latter is to be left free to revolve during the driving of the pile. The wheel x, 
 upon the third motion shaft, geers with a similar wheel a, fixed upon a cross-shaft T, working in bear- 
 ings under the platform, and serving to impart motion at once to the small chain-barrel b' for hoisting 
 
 e piles, and to the locomotive geer. A clutch, or coupling c, sliding upon the shaft T, enables the 
 
480 
 
 PILE-DRIVER— AMERICAN. 
 
 attendant to throw the small chain-barrel into geer with the driving apparatus or disengage it at 
 pleasure ; the remaining details of this part of the process will be fully understood by reference to Fig. 
 3034, where ». pile H' is shown suspended from the chain d', ready to come under the action of the 
 driving machinery. To adjust the pile-case over the head of the pile at the commencement of the 
 driving, it is of course necessary that one or two men should be raised to the summit of the machine. 
 A rope e' passed over a pulley at the top of the great upright, and wound round the barrel of a winch 
 U, serves to accomplish tills object. 
 
 The locomotive geer is exceedingly simple, and will be at once understood by referring to Figs. 3036 
 and 8037. A bevel-wheel/', fixed to the outer end of the shaft T, geers with another of equal diameter 
 working loose upon the shaft V, to which a pair of the locomotive wheels a a are fixed. When it is 
 required to move the platform, with its superincumbent machinery, along the line of rails, a sliding- 
 clutch g is thrown into geer with the last-mentioned bevel-wheel, and is disengaged when the machine 
 has arrived at the desired position. 
 
 Action of the machine. — The pile having been raised by means of the hoisting apparatus, and its 
 point having been set into the proper position, the pile-case G G, with its attached machinery, is low- 
 ered down over tin; head by reversing the small engine R, so that the jaws / f rest upon the shoulders 
 of the pile, which sinks down into the ground by the effect of the superincumbent weight, till it has 
 reached soil sufficiently firm to support it ; this is indicated by the chain cc becoming slack. The pin- 
 ion y is then thrown out of geer, and the steam is admitted into the driving-cylinder F by turning the 
 handle i. The hammer-block O is by this means raised till the inclined plane o' o", coming in contact 
 with the end of the valve-lever r, causes the valve k to assume the position represented in Fig. 
 3044. The steam which had served to raise the hammer is thus allowed to blow out into the air, 
 and the hammer descends and discharges its Momentum in the form of an energetic blow upon the 
 head of the pile. During the descent of the hammer-block, the steam-valve is retained in its proper 
 position by the action of the trigger s, but by the effect of the concussion upon the head of the pile, the 
 valve-spindle is released from contact with the trigger, and the steam-valve assumes the position indi- 
 cated in Fig. 3042, in' which circumstances the steam is allowed to act freely under the piston, for the 
 purpose of again raising the hammer. 
 
 Such is the rapidity with which these various movements and functions of the driving apparatus are 
 accomplished, that the machine may be easily made to perform 80 strokes per minute. Some idea may 
 be formed of the vast efficiency of this system of driving piles, when it is stated that, in ordinary 
 ground, piles of 14 inches square are driven at the rate of upwards of 10 feet per minute 1 
 
 At the conclusion of the driving of each pile, the action of the hammer is arrested by turning the 
 handle i, which cuts off the supply of steam. The great chain-barrel pinion is then thrown into geer 
 with the wheel on the barrel-shaft, and the small engine R is started, which rapidly raises the apparatus 
 off the head of the pile to the top of the great guide-pole C. In the mean time the locomotive action 
 is applied, and the machine brought opposite the next pile, when the process just described is repeated. 
 
 PILE-DRIVING MACHINE— THE AMERICAN STEAM. The following is a description of the 
 American steam pile-driving machine, and the operations for which it is applicable. 
 
 The machine consists of two pair of leaders, similar to the common hand machine, placed 6 feet from 
 centre to centre, and firmly bolted to a strong horizontal framing, and supported by two oblique lad- 
 ders. The frame is 9 feet wide to the outside of the framing, and 28 feet long ; it carries at one end 
 a locomotive boiler 11 feet long and 2 ft. 6 in. diameter, calculated to bear 120 lb. per square inch 
 pressure, but generally worked at 80 lb. per square inch, and about 100 strokes per minute. Under 
 the boiler is placed the supply cistern. In the centre of the framing, and on each side of the boiler, is a 
 pair of inclined cylinders 5J inch bore, with solid pistons working well without packing, and 14 inch 
 stroke, which act on right-angled crauks, and the geering, drums, Ac., described in the motions of the 
 machine; the shaft centres are 1' Z" apart, the spur-wheel has 56 and the pinion 19 teeth; bevels 101 
 and 40 teeth ; saw-pulley V 9" and 10i inches diameter. The ram is generally raised from 4 to 5 
 times a. minute, the steam being at 80 lb. per square inch. 
 
 For river work the machine is made much more compact, the apparatus is placed on each side and 
 over the boiler, so that the stage is little more than half the length of the machine shown in the en- 
 graving, and it is also sometimes made with an apparatus for driving one pile only, consequently re- 
 quiring smaller power. 
 
 In the drawing, Fig. 3050 is a side elevation of the machine; Fig. 3051 elevation in front of leaders, 
 showing saw, &c. ; Fig. 3052 a section taken in front of geering, ifec. ; Fig. 3053 a plan of geering end with 
 leaders and ladders removed, and showing saw in plan; similar letters refer to similar parts in each figure. 
 
 Taking up the pile. — The ram A being secured by placing the stop B under it, by means of the small 
 ropes attached to the latter, and passing over the small pulleys C C, to within three feet of the stage. 
 The dogs D are made fast to the pile, Fig. 3052, the rope attached to which passes upwards through 
 the small guide-pulleys and over the outer pulley E, passes downwards and is coiled round the pulley 
 F fixed on the shaft G, which being made to revolve, raises the pile to its place between the leaders, and 
 is then secured by the loose stay 11 and the iron work II' placed round it for guiding it perpendicularly. 
 
 Driving the pile. — The stop B being withdrawn from under the ram A, the ram is raised by a rope, 
 which, being secured to a staple on the top journal, passes down under the pulley I, then upwards over 
 the pulley K, and again downwards to the drum L, upon which the rope is coiled. The drum is placed 
 on the shaft G, which is made to revolve by the spur-wheel N working in the pinion O on the lower 
 shaft P, which shaft revolves by the action of two cranks Q, Figs. 3050 and 3052, placed on each end of 
 the shaft P ; the cranks are set at right angles to each other, and are worked by the connecting-rods R 
 attached to the piston-rods, which are furnished with slide parallels, as shown in Fig. 3050. The slide- 
 valves of the piston are worked by the eccentric V on the end of the shaft P. Steam is supplied to 
 the cylinder by the pipe S from the boiler T ; the boiler is supplied with water from the cistern M, 
 Fig- 3050, by the pump W, which is worked by the eccentric-rod X fixed on the spur nave at Y, or by 
 
PILE-DRIVER— AMERICAN. 
 
 481 
 
 the handle at Z ; the supply of steam is regulated by the handle a acting on a valve in the steam-pipe 
 S. The drum L consists of a fixed and a loose cylinder, the latter revolving by the friction of the for- 
 mer, (fixed,) and is brought into or out of contact by the hand-lever Y, Figs. 3050 and 3053, which has 
 a fulcrum attached to the standard. 
 
 The follower/ 7 is furnished with a pair of tongs or clippers, which takes hold of a staple fixed on the 
 ram and carries it to the top of the frame ; then, when the top of the tongs is pressed closer together 
 by coming between the contracted cheeks e' e\ the lower part opens and allows the ram to fall. 
 
 For working the apparatus, the engine-tender stands at the valve S, and a man at the lever y of each 
 machine. For raising the ram the man turns on the steam at the valve S, which sets in motion 
 the apparatus of each machine, coils the rope round the drums, and, at the same time, raises the 
 ram ; as soon as the latter reaches the top of the leaders, the ram is detached and descends ; at the 
 same moment the engine-tender turns off the steam, and the men at the levers y throw the drum out of 
 geer, which allows the clippers and chain to descend again and lay hold of the ram, when the drum is 
 again thrown into geer, the steam turned on, and the ram again raised, and so the operation is continued 
 until the pile is driven. 
 
 Drawing a pile . — Chain tackle is secured to the pile and passed over the top pulley to the drum L, 
 and is then drawn by applying the power to turn the drum of the apparatus. 
 
 ITie saw apparatus consists of a circular saw b, 4 feet diameter, having teeth set three inches apart, 
 secured to the end of a beam c, which beam works on the upright shaft d for a centre, and slides lat- 
 erally on the iron arc e; when used, the saw is adjusted to the proper height by the screws/, and a bar 
 having a hook in one end, and fitting into a staple in the beam’s end, is used to press the saw against 
 the work ; the bevel-pinion g being raised into geer by the foot-lever h, Fig. 3053, motion is given to 
 the pulleys i and^' and band k which work the saw b. The operation of sawing off the end of a pile 
 takes less than a minute. 
 
 Progressing motion . — The hook l being fastened to a driven pile, and the rope passed over the pulley 
 m attached to the side of the frame to the pulley F, round which it is coiled twice and the end held by 
 a man ; motion being now given to the drum the machine progresses ; this motion is shown by the 
 dotted rope, Fig. 3050. It should be stated that the frame is intended to be supported upon six rail- 
 way wheels, which run on a temporary rail laid on the top of the piles as they are driven. There is 
 another mode of progressing, but which is not found to answer so well, viz., by means of two sledge 
 beams faced with iron and attached to the under-framing ; these are placed six feet apart from centre 
 to centre, and pass under the whole length of the machine, and slide on small iron wheels fixed to 
 standards, which are placed loose on the piles. 
 
 The plumb-bob l suspended to a line regulates the pile being driven perpendicularly, and Y is a lever 
 attached to a friction baud break passing over the end of the drum, which is only used occasionally. 
 
 Vol. II.— 31 
 
482 
 
 PILING MACHINE. 
 
 For the steam machine it requires to work the engine and apparatus for driving two piles at one time, 
 with a ram weighing 16 cwt., the following men : an engine-tender, one man for throwing each apparatus 
 in and out of geer, and one man to attend to each pile, making altogether five men for driving two piles 
 For the ordinary machine it requires four men to work the crab-engine for lifting a ram of the same 
 
 3053. 
 
 weight, and one man to attend to the driving of the pile, making five men for each pile, or 10 men for 
 two piles. With the steam machine the ram is lifted four or five times in a minute, thereby the opera- 
 tion of driving the pile is very short in comparison with the ordinary machine. The cost of the steam 
 machine, with an engine of ten horse-power, tubular boiler and apparatus, is about 83500, and the cost 
 of the ordinary pile-driving machine, with crab-engine, is about 8350. 
 
 3058. 
 
 r ‘ — = a 
 
 J ^ L 
 
 PILING MACHINE. Fig. 3054 represents the side elevation, Fig. 3055 the front elevation, Fig, 
 3056 the plan, and Fig. 3057 a section of a pile-driver used at the construction of the Dry Dock. Brook 
 
PILING MACHINE. 
 
 483 
 
484 
 
 PILE, SCREW, AND SCREW-MOORING. 
 
 lyn Navy Yard, drawn to a scale of 8 feet to an inch. Fig. 3085 is a plan of the hammer, weighing 
 4050 pounds. 
 
 Figs. 3061, 3059, and 3060 are plan, elevation, and section of the nippers. 
 
 Fig. 3063, plan and elevation of head-pulley. 
 
 These machines were operated by steam ; the fall passing through the leading-blocks to the drum o; 
 a steam engine. 
 
 PILE, SCREW AND SCREW MOORING. To Alexander Mitchell, Esq., of Belfast, Ireland, the 
 profession is indebted for this discovery, by means of which we are now able to construct permanent 
 foundations in deep water, on shoals of sand, mud, clay, or gravel, or in fact on any bottom, excepting 
 solid rock, and to moor shipping of the largest class with a degree of security never before attained. 
 
 8063 
 
 The plan which appeared best adapted for obtaining a firm hold of soft ground or sand, was to insert 
 to a considerable distance beneath the surface a bar of iron, fig. 3063, having at its lower extremity a 
 broad plate, or disk of metal, in a spiral or helical form, on the principle of the screw, in order that it 
 should enter the ground with facility, thrusting aside any obstacles to its descent, without materially dis- 
 turbing the texture of the strata it passed through, and that it should at the same time offer an ex- 
 tended base, either for resisting downward pressure, or an upward strain. 
 
 Whether this broad spiral flange, or “ ground-screw,” as it may he termed, he applied to the foot of a 
 pile to support a superincumbent weight, or be employed as a mooring to resist an upward strain, its 
 holding power entirely depends upon the area of its disk, the nature of the ground into which it is in- 
 serted, and the depth to which it is forced beneath the surface. 
 
 The proper area of the screw should, in every case, be determined by the nature of tho ground in 
 
PILE, SCREW, AND SCREW-MOORING. 
 
 48, 
 
 which it is to he placed, and which mnst be ascertained by previous experiment. The largest size 
 nitherto used has been 4 feet in diameter ; but within certain sizes, prescribed by the facility of manufac- 
 turing them, the dimensions may be extended to meet any case, and may be said to be limited only bj 
 the power available for forcing them into the ground. 
 
 Either the screw-pile or the screw-mooring can be employed in every description of ground, hard 
 rock alone excepted ; for its helical form enables it to force its way among stones, and even to thrust 
 aside medium-sized boulders. In ports, harbors, estuaries, and roadsteads, rock is, however, seldom met 
 with, except in detached masses, the ground being usually an accumulation of alluvial deposit, which 
 is well adapted for the reception of such foundations, and is also that in which they are generally most 
 required. 
 
 The ground-screw has been already extensively used for several purposes, and its applicability to 
 many others will be evident from a succinct account of its present employment. 
 
 The fixed or permanent moorings at present most commonly used are of two kinds — the span-chain 
 mooring, and the sinker, or mooring-block. 
 
 The former of these consists of a strong chain of considerable length, stretched along the ground 
 (across the river), and retained by heavy anchors, or mooring blocks, at either end, and to the middle 
 of the ground-chain the buoy-chain is shackled. 
 
 The other kind, which is more generally employed, consists of a heavy sinker, to which a strong chain 
 is attached, extending to a buoy shackled at the other end (fig. 3064). This sinker, which is a block of 
 stone or iron, is either laid upon the surface of the ground, or is placed in an excavation prepared for 
 its reception. As a simple, effective, and at the same time an inexpensive mode of holding the buoy- 
 chain down, Mr. Mitchell adopted a modification of the screw-pile, fig 3065, because it offers great facil- 
 ities for entering the ground, and when arrived at the required depth, it evidently affords greater holding 
 power than any other form. 
 
 Every description of earth is more or less adhesive, and the greater its tenacity, the larger must be 
 the portion disturbed, before the mooring can be displaced by any direct force. The mass of ground 
 thus affected, in the case of the screw-mooring, is in the form of a frustrum of a cone, inverted ; that 
 is, with its base at the surface, the breadth of the base being in proportion to the tenacity of the 
 ground ; this is pressed on by a cylinder of water equal to its diameter, the axis of which is its deptlr, 
 and the water again bears the weight of a column of air of the diameter of the cylinder. 
 
 It is evident, therefore, that if a cast iron screw, of a given area, be forced into the earth to a certain 
 depth, it must afford a firm point of attachment for a buoy-chain in every direction (fig. 3066), and will 
 oppose a powerful resistance, even to a vertical strain, which generally proves fatal to sinker moorings, 
 depending (as they do) chiefly on their specific gravity. 
 
 The first trials were upon a comparatively small scale ; but their success was so decisive that the 
 merits of the moorings were acknowledged, and their use soon became extended. 
 
 The depth to v r hich these moorings have been screwed varies from 8 to 18 feet; the former is deep 
 enough where the soil is of a firm and unyielding description, and the latter depth is found to give suffi- 
 cient firmness in a very weak bottom. It is evident from its form, that every part of the screw-mooring 
 is so far beneath the surface, as to prevent a vessel from receiving injury from grounding immediately 
 above it, the mooring chain alone protruding from the ground ; and it is also obvious that anchors, 
 dropped in the neighborhood, cannot be hooked into or get foul of the chain, one end alone being at- 
 tached to the ground. 
 
 In fixing these moorings in the ports and harbors where they have been used, the persons hitherto 
 engaged in the operation have been generally compelled to avail themselves of any means within their 
 reach, for the construction of a floating stage, or platform, on which the men could execute the work. 
 Barges, lighters, and pontoons have been therefore indifferently employed ; those that were without ■ 
 decks being planked over for the purpose. Two such vessels being lashed broadside to each other, with 
 a certain space between them, are securely moored over the spot, and the screw-mooring lowered, with 
 the chain attached to the shackle, from the centre of the stage, to the level of the water, and as it de- 
 scends to the bottom the lengths of the apparatus for screwing it into the ground are successively at- 
 tached. 
 
 This apparatus, fig. 3067, consists of a strong wrought-iron shaft, in lengths of 10 or 12 feet each, 
 connected with each other by key-joints or couplings, the lower extremity having a square socket to fit 
 the head of the centre pin, or axis, of the mooring. When the centre pin rests on the bottom, a capstan 
 is firmly keyed upon the shaft at a convenient height ; the men then shift the capstan bars and apply 
 their power whilst travelling round upon the stage, the capstan being lifted and again fixed as the moor- 
 ing is screwed down into the ground. The operation is continued until the men can no longer move the 
 shaft round, or until it is considered to have been forced to a sufficient depth. 
 
 The most important purpose to which the screw-pile has hitherto been applied, to any considerable 
 extent, is for forming the foundations of lighthouses, beacons, and jetties, in situations where the soil, 
 or sand, is so loose and unstable, as to be incapable of supporting any massive structure, or whore the 
 waves have so much power of undermining by their continuous action, or beat so heavily, that the sta- 
 bility of any mass of masonry would be seriously endangered. 
 
 In 1838, Mr. Mitchell and his son laid the foundation of the Maplin Sand Lighthouse. Before deter- 
 mining the length of the piles and the area of the screws to be employed, a careful examination of the 
 ground was made, and it was proposed to use nine malleable-iron piles of 5 inches diameter, and 26 feet 
 in length, with a cast-iron screw of 4 feet diameter, secured to the foot of each. Eight of the piles 
 were placed at the angles of an octagon, and one in the centre ; these were put down in nine consecu- 
 tive days, being screwed into the bank to the depth of 22 feet, leaving 4 feet above the surface. The 
 tile rises on the bank about 16 feet, and seldom leaves the surface dry. 
 
 The instrument used in trying the nature of the ground was also employed in testing its holding 
 
486 
 
 PILE, SCREW, AND SCREW-MOORING 
 
 power. It consisted of a jointed rod 30 feet long, and inch in diameter, having at its foot a spiral 
 flange of 6 inches diameter. It was moved round by means of cross levers, keyed upon the boring-rod 
 and upon these levers, when the screw was turned to the depth of 27 feet, a few boards were laid, form 
 ing a platform sufficiently large to support twelve men. A bar was then driven into the bank at some 
 distance, its top being brought to the same level as that of the boring-rod. Twelve men were theE 
 placed upon the platform to ascertain if their weight, together with the apparatus, in all about one ton, 
 sufficed to depress the screw. After some time the men were removed, and the level was again applied) 
 but no sensible depression of the screw could be observed. 
 
 The inference from it was, that if a screw of 6 
 inches in diameter could support one ton, one of 
 4 feet diameter was capable of supporting at 
 least 64 tons, the comparative area of their sur- 
 faces being as the square of their diameters ; but 
 this experiment was nothing more than an ap- 
 proximation to the truth, a continuous surface 
 possessing a much greater sustaining power than 
 the same area in detached portions. 
 
 In fixing the foundation piles for the Maplin 
 Sand Lighthouse, a raft of 36 feet square was 
 used as a stage, or platform, upon which the men 
 worked, as barges would have been too high 
 from the surface, and “ it was necessary to ground the raft itself,” 
 before the piles could be screwed down to the required depth, 
 their heads being only a short distance above the bank. The 
 raft was constructed of balks of American timber bolted together, 
 leaving an aperture of two feet in width from one side to the cen- 
 tre, by which the pile was brought to its position. 
 
 A screw-pile lighthouse of iron has been constructed on the 
 Brandywine Shoal, in Delaware Bay, under the orders of the 
 Bureau of Topographical Engineers. This work being very much 
 exposed to the action of fields of drift ice during the winter 
 months, it was deemed prudent to protect it by an exterior work 
 that should serve as an ice-fender: this consists of 30 screw-piles 
 of wrought-iron of 5 inches diameter. These 30 piles are placed 
 in symmetrical order, so as to form an oblong hexagon, 75 feet 
 on the largest diameter, and 45 feet on the shorter. The piles are 
 framed together at their heads by ties of 3-inch round iron, keyed 
 into cast-iron sleeves fitted to the pile-heads. A similar system 
 of ties connects the piles at the plane of low water. The nine 
 piles that form the foundation of the lighthouse are inclosed in 
 this system, which has been found, during a series of winters, a 
 most effectual protection against the heaviest drifts of field-ice — 
 no injury w'hatever having thus far been sustained by any part of 
 the work. 
 
 Under the same Bureau, a screw-pile lighthouse of great size 
 has been commenced on the Florida Beefs at Sand Key, and the 
 foundation already completed. This work is quite peculiar, and 
 has many novel features. The principal one is, however, the 
 modification of the form of the screw, into something like a screw 
 auger, enabling the engineer thereby to penetrate through solid 
 masses of coral, of which these reefs are entirely composed. This 
 invention enables the government to erect a chain of lights along 
 the whole reef (upwards of 250 miles long), and right on the edge 
 of the Gulf stream. 
 
 Previously it was thought impracticable to locate any perma- 
 nent structure on these reefs, as in hurricane seasons they are 
 deeply submerged, and exposed to a tremendous sea from the Gulf 
 stream. By means of the screw-pile, as modified for this locality, 
 all difficulties are now surmounted, and it is supposed that within 
 a few years the whole reef will be illuminated, and rendered 
 safely navigable. 
 
 The superintendent of the United States Coast Survey has 
 adopted this modified screw-pile to establish, on the Florida 
 Beefs, his marks of triangulation, the old form of tripod being 
 annually washed away, and their replacement attended with a 
 great expense. To the screw is attached a tube of cast-iron 8 
 fe^t long ; by means of this tube, which takes the place of the ordinary pile, the screw is inserted into 
 the reef 4 or 5 feet deep. A long signal pole, with a cone or ball on top, is then inserted in the iron 
 tube, and will stand erect during the heaviest storms. The number ot wrecks on these reefs has greatly 
 dininished since the operations of the Coast Survey were commenced. 
 
 Three beacons have been erected by Mitchell & Son for the Dublin Ballast Board, ^ on the Kish Bank, 
 the Arklow Bank, and the Blackwater Bank, which are parts of the same shoal. Ihese have all been 
 
PILE, SCREW, AND SCREW-MOORING. 
 
 4S7 
 
 put down with the intention of placing lighthouses on their sites, should they appear eventually to suffer 
 no change by the action of the sea. All these beacons are similar in form and principle (fig. 3068) 
 each consisting of a single pile of wrought-iron in two joints, connected by a strong screw-coupling, 
 and measuring, when together, 63 feet in length ; their diameter at the surface of the ground is 8 inches, 
 diminishing from thence both up and down. 
 
 The incompressible nature of the sand offering considerable opposition to the descent of the pile, 
 screws of only 2 feet in diameter were used, and on the top of each pile, when fixed, a ball was placed 
 of 3 feet 6 inches diameter. The screws used for the Blackwater and the Arklow beacons were forged 
 of malleable iron, and turned in the lathe, at great expense ; but that will probably never again bo 
 necessary, as they can generally be quite as well made of cast-iron, and at much less cost. 
 
 One of these beacons was fixed in June, 1843, the other two in the summer of 1846, and are all 
 standing, though two of them diverge considerably from the perpendicular, having been frequently 
 struck by vessels in heavy weather. 
 
 The engineer of the Great Portland Breakwater, which the British government have ordered to be 
 constructed as a harbor of refuge for the Channel fleets, has applied the screw-pile in a novel and effi- 
 cient manner. On the axial line of the breakwater a viaduct of screw-piles is erected, bearing a railway, 
 which extends inland to the quarries, and is prolonged seaward as fast as the growth of the work requires. 
 The stone of which the breakwater is to consist is thus brought direct from the quarry by rail, to the site, 
 and there dumped into the water. The screw-pile viaduct is of course buried up in the mass of the 
 breakwater ; but an enormous saving has been effected by this arrangement, when compared with that 
 pursued at the Plymouth Works. An extensive railway viaduct was erected on screw-piles over the 
 fens of Linconshire in 1849, by Mr. W. Cubitt, and other similar structures are now in progress. 
 
 Messrs. Ransomes and May (of Ipswich, England) have constructed several kinds of cast-iron screw- 
 points, shown in figs. 3069, 3070, 3071, and 3072. 
 
 8069 
 
 8070 
 
 Fig. 3069 shows the largest size, weighing 2 
 cwt. 3 qrs. 14 lbs., adapted for whole timber piles, 
 which are often so splintered and shattered, and 
 even set on fire, by the rapid blows of the steam 
 pile-driver, when traversing compact ground, and 
 where wrought-iron shoes are generally crushed 
 into the timber even in ordinary ground, with 
 the force of the common pile-engine. The small 
 screw-point opens the way for the conical part, 
 and the larger screw not only draws the pile 
 down, but, when it has penetrated to a sufficient 
 depth, affords an extended base for preventing 
 further .depression. Thus several feet of timbei 
 must be saved, and the general length of the pile 
 can be reduced, as it will bear a greater weight 
 and offer a more solid base when introduced 
 to a less distance, than when it rests upon the 
 ordinary sharp, wrought-iron pointed shoe. 
 
 8071 
 
 Fig. 3070, weighing 3 qrs. 22 lbs., shows the shape adapted for railway signal-posts ; and fig. 3071, 
 weighing 2 qrs. 4 lbs., that for the supports for the wires of the electric telegraph. For these purposes 
 the screw-points must be very useful, as independent of the economy of labor in putting them down by 
 merely screwing them into the ground, instead of digging holes to introduce the cross-feet, all possibility 
 of injury to the banks would be precluded ; whereas at. present there is always a liability of causing a 
 slip by disturbing uncertain ground, and admitting water in the sides of cuttings. 
 
488 
 
 PILE, SCREW, AND SCREW MOORING. 
 
 The cast-iron screw socket-points, fig. 30G9, have recently teen very successfully applied for the sup 
 porting posts or columns of timber-sheds and buildings for railway stations and other purposes. 
 
 Fig. 3072 shows the applicability to smaller objects, and a tent-pin has been selected as the most famil 
 iar example, as it requires to be removed so frequently, and shows the use that may be made of the 
 screw for the standards of fencing, and for an infinite number of agricultural and other purposes. 
 
 The diagram given below represents four lighthouses that have been erected on the “ skeleton frame 
 tower system,” with screw-pile foundations. The whole of these structures are drawn to one scale, sc 
 that at a glance their comparative magnitudes in elevation and area of foundations are immediately 
 visible. The Brandywine Lighthouse i3 erected upon the shoal of that name at the mouth of Delaware 
 
 Sand Key, 1851. Brandywine, 1849. Maplin, 1840. Fleetwood, 1839. 
 
 in form, and consists of two stories. The prevalence of vast fields of ice in the Delaware in winter, 
 rendered it advisable to protect the frame of the tower by surrounding it with a system of thirty 5 
 inch screw-piles, arranged in the form of a hexagon of 75 by 45 feet, the longer axis of the polygon 
 being parallel to the thread of the current. This ice-breaker has proved perfectly efficient after a trial 
 of seven winters. 
 
 The screw-pile lighthouse at Sand Key, constructed by I. W. P. Lewis, is different in design and de- 
 tail from all that have preceded it. On reference to the diagram, it will be seen that the base is square. 
 It was found while constructing the Brandywine and Carysfoot lighthouses, that there was a want of 
 rigidity in the frame-tower, and that the application of any external force produced a vibratory move- 
 ment about the central axis of the frame. Secondly, it was observed that in tying all the horizontal 
 framing to a common centre, there was a very unequal distribution of metal and strength — the centre pile 
 bearing 6 or 8 times the load borne by any one of the angle piles. Both these important defects are 
 entirely remedied by adopting the square base. The tower at Sand Key requiring to be of the first 
 class, it was decided to increase the number of piles to 16, and one auxiliary pile in the centre to bear 
 the weight of the staircase. The foundation thus is formed of 17 screw-piles of 8 inches diameter, armed 
 with a modified form of screw 2 feet in diameter. A survey in 1850 by the engineer, enabled him to 
 design a form of screw, similar in principle to a centre-bit auger, which should with a very slow motion 
 tut. its way through the coral. This screw was entirely successful ; being slowly turned by powerful 
 Machinery, it descended through the coral about 2 inches for each revolution. 
 
 The screws are bored 12 feet into the reef, and the pile-heads being framed and braced together as 
 shown in the diagram, a perfectly rigid and firm foundation is obtained. 
 
 The superstructure of the frame-tower consists of six series of cast-iron tubular columns, framed to- 
 gether with wrought-iron ties at each joint, and braced diagonally on the faces of each tier, as seen in 
 the diagram ; the rigidity of such a system of pillars and braces can be easily estimated. 
 
 The keeper’s house rests on a floor of cast-iron, supported upon cast-iron girders and joists, at the 
 height of 20 feet above the plane of the foundation top ; this is higher by 15 feet than the great hurri- 
 
^IN-MAKING MACHINE 
 
 489 
 
 cane tide of 1846, and beyond the reach of any sea that could rise there, the surrounding coral reel 
 forming a perfect breakwater. 
 
 The foundation of Sand Key Lighthouse measures 50 feet on the side of the square, and its tota. 
 height is 132 feet, or 120 feet above high-water level. The site is a small bank of calcareous sand 
 thrown up by the combined effects of wind and tide, to the height of 4 feet above mean high water, and 
 in depth about 2 feet below low-water leveL 
 
 PIN-MAKING MACHINE. An improved method of making pins, by John J. Howe, of New 
 Haven, Connecticut. The wire having been properly straightened and placed in a coil upon a suitable 
 reel, and having one of its ends introduced in a proper manner into the machine, is, in successive por- 
 tions, drawn in and converted into pins, by the action of the machine ; each pin so made by the machine 
 consisting of a single piece of metal or wire, the head of the pin being upset or raised, and formed at 
 one end, and the other end being sharpened in a suitable manner, to form the point. The following is a 
 full and exact description thereof, and of the manner of constructing and using the same, reference being 
 had to the accompanying figures. 
 
 The individual parts of the machine are marked in the drawings with capital letters, with small 
 letters, and with numbers respectively ; and the same marks of reference refer in all cases to the same 
 or similar parts. 
 
 Of tlie driving-povicr . — The machine is put in motion through a driving-shaft F, which has its bear- 
 ings formed in the portion A 7 of the fixed frame, shown in Fig. 8064. The shaft F is placed at right 
 angles to the main-shaft B, and both of said shafts are in a horizontal position in the same plane with 
 each other. 
 
 On the outer end of the shaft F are fixed a fast pulley 1, a loose pulley 2, a fly-wheel 3, and a pulley 4, 
 for driving the shaft L, which carries the pulleys 45 for driving the pointing mills, and on the inner end 
 of said shaft F is fixed a bevel-pinion G. The aforesaid bevel-pinion G works into the bevel-wheel K, 
 which is fixed on the shaft B, said wheel having four times the number of teeth of the pinion G, so that 
 four revolutions of the driving-shaft F communicate one revolution to the shaft B. The horizontal shaft B 
 is connected with the vertical shaft c by bevel and spur geering, so that both the said shafts revolve in 
 the same time in the direction indicated by the arrows on the respective shafts, as is shown in Fig. 3063. 
 The mitre bevel-wheel HI on the shaft B works into the mitre bevel-wheel H2, which has its axis 
 placed perpendicularly beneath the shaft B. On the axis of the bevel-wheel H2 is fixed a spur-wheel 
 12, which works into a similar spur-wheel fixed on the vertical shaft c. 
 
 The pulley 4, Fig. 3067, is connected by a belt to the pulley 5 on the shaft L, for the purpose of com- 
 municating an accelerated rotary motion to the shaft L. On tjie shaft L are the pulleys 45, which are 
 respectively connected by bands 44 with the pulleys 43, Fig. 3063, on the arbors or spindles of the 
 mills or revolving circular files 38, for the purpose of communicating the necessary rapid rotary motion 
 to said mills, by which the points of the pins are ground and sharpened. 
 
 Of the feeding and cutting apparatus — Fig. 3069 is a perspective view of the combined apparatus for 
 feeding in and cutting off the wire, with a portion of the semicircular horizontal part of the frame, 
 to which the principal parts of said apparatus are attached. Other views of said apparatus are repre- 
 sented in Figs. 3063 and 3064. The fixed portion of the feeding apparatus consists of a horizontal 
 part 8a and two arms, 86 and 8c, depending in a perpendicular direction from the under side of said 
 horizontal portion. The horizontal portion 8a has an oblong opening through it, extending in a hori- 
 zontal direction from within towards the shaft c outwards. The two vertical surfaces of said portion, 8a, 
 are dressed straight and parallel with each other, and the two sides of the aforesaid oblong opening are 
 also dressed straight and parallel with each other. A slide 9 d, which rest3 against the front vertical 
 face of the portion 8a, is connected through the said opening in 8a with a cap, which rests against 
 the back vertical face of the portion 8a, and the portion by which the slide 9a is connected with the 
 cap 96 is so formed and fitted into said opening as to allow said slide to move freely forward and 
 backward, but not to turn or move in any other direction. The slide 9a has a stud 9c standing out 
 horizontally at right angles to and near the centre of its face. There is a small hole made horizontally 
 through said stud close to the face of the slide, through which, and also through an eye formed for the 
 purpose, near each end of the slide, the wire is introduced in a horizontal direction from right to left. 
 There is a steel cap 10 fitted by a hole in its centre on the stud 9c, behind which the wire is introduced 
 as aforesaid, in the manner represented in Fig. 3069. The lever 11 of the feeder has a fork at its upper 
 end to receive the stud 9c, and near its lower end it has the stud 11a and the plate 116 to receive the 
 action of the feeder-cam a; the lever 11 is jointed to the extremities of the two arms 86 and 8c of the 
 feeder-frame 8 a6c by the ring 12, and the four centre or pivot screws 13, Fig. 3069, so as to furnish 
 said lever with two horizontal axes intersecting each other at right angles in the manner of a universal 
 joint ; by means of which the forked end of said lever is allowed to be alternately pressed against the 
 cap 10 and then removed from it, at the same time that it has a reciprocating motion forward and back- 
 ward, for the purpose of carrying forward the feeder 9a in the act of introducing the wire and then 
 carrying said feeder back, in order to its introducing another portion of wire. The cam a, by which the 
 movements and actions of the feeder are produced, is represented in Fig. 3069. Said cam a (revolving 
 in the direction indicated by the arrow) acts by the face a2 on its periphery against the stud 11a of the 
 lever 11 to carry forward the feeder 9, and by the face 13, on its periphery, to retain said feeder for a 
 short period in the advanced position to which it had been previously carried ; the face a3 of said cam 
 being concentric with the axis B, on which said cam is fixed ; said cam a has a rib or raised portion dl 
 on its side, by which it acts against the plate 116 of the lever 11 to press the forked end of said lever 
 against the cap 10 of the feeder, in order to grasp the wire in the act of feeding it into the machine. A 
 spiral spring 14 is attached to the lower end of the lever 11, below its stud and plate aforesaid, and t.> 
 6ome part of the fixed frame, so as to draw obliquely inward that end of said lever, and to retract it as 
 soon as the cam a recedes after having performed its aforesaid actions respectively on said stud 11a and 
 plate 116. 
 
490 
 
 PIN-MAKING MACHINE. 
 
 A gage-screw 15 is fitted into the exterior end of the portion 8a of the feeder-frame, against the poin* 
 of which the slide of the feeder stops, when it is carried back in the manner above described by the 
 spring 14. By turning the aforesaid gage-screw 15 out or in, the length of the portion of wire intro 
 duced at each operation of the feeder may be graduated according to the proposed length of the pin 
 
 When in the rotation of the cam a its rib al comes against the plate 115 of the lever 11, it crowds the 
 lower end of said lever back in the direction of the length of the shaft B, so as to press its upper o 1 ' 
 forked end against the cap 10, pressing said cap against the wire, so that the wire is embraced and 
 firmly held between said cap 10 and the face of the slide 9. and while the wire continues to be held the 
 
PIN-MAKING MACHINE. 
 
 491 
 
 rising face on the periphery of the cam a comes against the stud 1 \d of the lever 1 1, crowding the low sr 
 end of said lever back in a direction at right angles to the length of the shaft B, and consequently 
 carrying forward the upper or forked end of said lever, which, holding on to the stud 9c of the feeder bj 
 the fork in its end, carries forward the feeder, holding the wire in the manner above described. 
 
 In the regular operation of the machine, where the wire is carried forward by the feeder, the end of 
 the wire enters one of the pointing chucks hereinafter described, which is in readiness to receive it; and 
 in order to insure the entrance thereof a guide is placed near the extremity of said chuck : said guide is 
 in the form of a hollow cone, having its apex directed towards the chuck, and its base towards the 
 feeder. There must be a perforation at the apex of the cone to allow the wire to pass through in a 
 straight line from the feeder to the chuck ; and there must also be an opening made in its side to allow 
 the chuck to carry the pin, or wire, out laterally : said guide may be attached to the cutter-staud or any 
 convenient part of the faxed frame. 
 
 Before the concentric face a3, before described, of the cam d, leaves the etud 11 d, the rib dl of said 
 ^am will leave the plate 116, so as to allow the spring II to retract the forked end of the lever 11 from 
 the cap 10 ; and afterwards said high concentric part of the cam a passing away from the stud 11a, will 
 leave the feeder free to be carried back by the action of the spring II, till it is stopped by coming 
 against the gage-screw 15. The apparatus for cutting off the wire, and also for holding it after it has 
 been introduced by the feeder, while the feeder is going back and renewing its grasp on the wire, in 
 order to introduce another succeeding portion of wire, is supported by and consists in part of an ad ■ 
 justable frame-piece or stand, which is fastened by a screw on the top of the portion AI of the fixed 
 frame, close behind the frame 8 of the feeding apparatus, as represented in Fig. 3063. At the interior 
 extremity of the stand 16 it has a portion 16a which extends across in front of the interior extremity of 
 
492 
 
 PIN-MAKING MACHINE. 
 
 (lie portion 8 d of the feeder-frame, furnishing in front towards the vertical shaft c (or the centre of the 
 revolving table D) a vertical plain surface at right angles to the line in which the wire is fed into the 
 machine. To the aforesaid vertical face of the portion 16<i of the cutter-stand is fitted a steel plate 
 This plate has a hole through it of a suitable size and in a proper situation to let the wire pass 
 through it in a straight line from the feeder to the pointing chuck, into which chuck the wire enters, 
 previous to a portion of it being cut off to form a pin. A steel cutter 18 is fitted into a groove or 
 socket in the cutter-stock 19, so as to admit of its being adjusted and fixed therein by screws, and tc 
 cause the cutting edge of said cutter to lie flat against the plate. The cutter-stock 19 is jointed to the 
 vertical portion 1 (id of the cutter-stand by means of a centre-screw 22, so that 19 forms the short arm 
 of which 19 d forms the long arm. 
 
 A small projection or plate 19c extending from the edge of the arm 1 9c? of said lever rests upon the 
 periphery of the cutter-cam 6, and a stud standing out laterally from said arm 19<6 at right angles tc 
 the plane of its motion on its centre 22, rests against the side of said cam b , on which side the acting 
 parts of said cam are formed. The cam b is circular and concentric with the shaft B on which it is 
 fixed, and has its acting parts formed on the side of it next to the aforesaid stud of the lever 19. 
 61 is a recess or low part, which is connected by an inclined portion at one of its extremities to the 
 raised part 62, and at its other extremity to the tooth or pivot 63 ; the portion or face 62 is a plain 
 surface coinciding with the plane in which the cam 6 revolves ; and the tooth 63 is a wedge-shaped 
 projection raised upon one extremity of the face 62. A spiral spring 235, which connects the extrem- 
 ity of the arm 19 d with the fixed frame, serves to draw said arm in a direction contrary to that in 
 winch it is moved by the action of the cam 6, and to retract the cutter immediately after its action 
 
PIN-MAKING MACHINE. 
 
 493 
 
 in cutting off the wire. The cam 6 must be adjusted on the shaft B, in reference to the feeder-cam d, sc 
 that its recess or low part 61 will be opposite the stud of the lever 19 during the time in which the 
 said cam d is engaged in carrying forwards the feeder to feed in the wire; and while the cam d con- 
 tinues to hold the feeder in its advanced position, and before the feeder relaxes its hold upon the wire, 
 iu the manner before described, the face 62 of the cutter-cam must arrive at the stud of the lever 19, 
 so as to cause the cutter 18 to close upon the wire and hold it without cutting it off; and while the face 
 62 of the cutter-cam is passing the stud, and before the tooth 63 reaches said stud, the feeder must 
 relax its grasp on the wire ; and then before the feeder begins to advance, and while it remains station- 
 ary in its retracted position, the tooth 63 of the cutter-cam must pass the stud, by which the cutter 18 
 will be suddenly further advanced to cut off the wire close to the face of the plate, against which the 
 flat side of the cutter plays, and by the reaction of the spring 235 the stud will be drawn against the 
 
 low part 61 of the cutter-cam, so as to retract the cutter 18 out of the way, to allow the feeder to intro- 
 duce another succeeding portion of wire. The length of wire fed in and cut off at each operation ot 
 the feeding and cutting apparatus is equal to the length of the pin to be made, and a portion of wire 
 sufficient, by being raised or upset and properly compressed between suitable dies, to form the head 
 of the pin. 
 
 Of the pointing-chucks and revolving table, and other parts accessor g to their movements . — In the pro- 
 cess of sharpening the points of the pins made by the machine herein described, the piece of wire 
 is held and turned round by a chuck formed at the extremity of a revolving axis, in a manner similar to 
 that in which a piece of work is held and turned in the chuck of a turning-lathe ; but the end of the 
 wire is reduced to the requisite tapering and pointed form by the grinding action of circular revolving 
 
 files, and not by the point or edge of a tool, as in the common operation of turning. There are eight 
 such chucks, mounted in suitable bearings on a revolving table D. The revolving table D is placed in 
 a horizontal position on the vertical shaft c , as is shown in Figs. 3063, 3064, and 3068. It has a hole 
 in its centre fitted to said shaft, so as to allow said shaft to revolve while the table is at rest, and to 
 allow said table to move round said shaft on its axis or centre of motion, when said table moves round 
 by an intermitting motion. The upper horizontal face of said table furnishes plane surfaces to which 
 are fitted and fastened, by screws, the bearings or boxes of the pointing-chucks 28, and said table has on 
 its back or under side a hub, which rests upon a collar on the shaft c, and which is also fitted into a 
 hole iu the middle of the girt A6. It has on its under side, near its circumference, a rim extending ver 
 
494 
 
 PIN-MAKING MACHINE. 
 
 tically downwards, which is divided at its lower edge into eight equal divisions or teeth, similar to saw 
 teeth, as is shown in Fig. 3068. In said Fig. 3068 the above-described rim is represented in section 
 with all the other parts of the table removed, in order to show the aforesaid divisions or teeth, which are 
 marked in the figure D 1 to 8. 
 
 There is a semicircular groove formed around the circumference of the aforesaid rim, above the bot 
 toms of its teeth, to receive the clip-band ef. The clip-band ef is formed of a band of round iron or 
 wire of a size to fit the aforesaid groove. The ends of said rod e (being straight) are passed through 
 eyes in the yokes / and are secured in that situation by nuts which are screwed on to said ends of the 
 
 rod e. The yoke/ is placed in a horizontal position, and presents towards the table D a concave side, 
 which is fitted to the groove in the rim of said table. Said yoke /has a vertical shot formed through 
 it, the longitudinal centre of wliich is in continuation of a right line extending horizontally outwards 
 from the centre of the axis c. By means of a stud 23 which extends upwards in a perpendicular direction 
 through the aforesaid shot in yoke/, from the end of the lever g to which said stud is attached, a con- 
 nection is formed between said yoke /and said lever g, so that when said lever g is moved horizontally 
 
 to the right or left hand, it communicates a corresponding movement to said yoke. The lever g is 
 connected by a vertical axis 24 to the fixed frame, as is shown also at 24 in Figs. 3063 and 3064 : it 
 has a broad part in which is a slot or opening of sufficient dimensions to allow the shaft c to pass through 
 it, and to allow said lever to move forwards and backwards to a certain extent around its axis 24. A 
 stud 26 is attached to the broad part of the lever g, in a suitable position to receive the action of the 
 cam /t, which is fixed on the vertical shaft c. The cam h has two eccentric faces on its periphery, viz., 
 the longer face hi which extends around three-fourths of the circle of the periphery ; and the shorte» 
 
PIPE MACHINE, LEAD. 
 
 495 
 
 face h2 which occupies one-fourth of said circle. A spring 26 connects the end of the lever g with the 
 fixed frame, and draws said lever in such a direction as to incline the stud 25 of said lever inwards to- 
 wards the vertical axis c. 
 
 In the machine herein described the cam h is placed beneath the lever g, and the stud 25 is affixed to 
 the under side of said lever. In Fig. 3068 said cam li is represented above said lever, and the stud 25 
 affixed to its upper side, in order to show the action of said cam upon said stud. 
 
 There is a spring-catch 27 attached to the 
 girt A6, which allows the table D to move 
 round freely in the direction of the arrow, by 
 yielding under the inclined faces of the teeth 
 D of said table ; but which prevents or arrests 
 a retrograde movement of said table, by 
 springing up behind the perpendicular faces 
 of said teeth and catching against one of said 
 perpendicular faces if an effort be made to 
 move said table in a retrograde direction. 
 
 The table moves forwards around the axis c 
 in the direction indicated by the arrow marked 
 on the rim d of said table, as shown in Fig. 
 
 3068, one-eighth of a revolution at each rev- 
 olution of the shaft c. It occupies one-fourth 
 of the time of a revolution of the shaft c in 
 making said movement, and it remains at rest 
 during three-fourths of the time of a revolu- 
 tion of said shaft c. The aforesaid alternate 
 periods of motion and rest of the table D are 
 produced by the above-described combina- 
 tion, which is marked in the figures referred 
 to in the foregoing description with the fol- 
 lowing letters and figures: C, D, d, (1 to 8,) 
 
 «,/, 23, g, 24, Al, A4, A6, 27 h, (1 to 3,) 25, 26, 
 in the following manner : that is to say, sup- 
 posing all the parts of the aforesaid combi- 
 nation which are shown in the figures to be 
 in the positions relatively to each other in 
 which they are represented, and that the 
 shaft c and the cam h are in the act of re- 
 volving in the direction indicated by the ar- 
 rows ; the face hi of the cam h advancing 
 against the stud 25 of the lever g, will carry 
 back said lever, and with it the clip-band 
 fe\ but the table D will be prevented from moving back along with the clip-band ef in consequence 'ol 
 the tooth of said tabic being arrested by the catch 27 ; consequently the clip-band will slip round in 
 the groove of said table D, and said table D will remain stationary. 
 
 FIPE MACHINE, LEAD. Until 1820 lead pipe was manufactured by casting and drawing 
 something similar to the process of wire-drawing. In 1820, Burr took out a patent in England 
 on the following plan : (in these figures, so much of the machine is represented as is essentia) 
 3077 3078 3080 
 
496 
 
 PISE-WORK. 
 
 to illustrate tlie principle of its action, without aiming at accuracy rf detail.) A hollow cylinder c, of 
 cast iron (fig. 3077) is furnished with a steel die d, of the shape and dimensions of the outside of the pro- 
 posed pipe. A solid piston or ram r, of cast iron, fits this hollow cylinder as snugly as possible, without 
 friction. To the bottom of this piston is affixed a steel mandril or core m , of the length of the cylinder, 
 and of the diameter of the bore of the proposed pipe. IVhen this piston is withdrawn from the cylinder, 
 the point of the mandril is just within the die at the bottom of the cylinder. The cylinder is then filled 
 with melted lead, which is allowed to set. By the action of a hydrostatic press the cylinder is then 
 raised between guides, or the piston lowered (it matters not which), and the solid lead is forced by the 
 action of the piston through the die, and enveloping the mandril runs off the point of the latter as lead 
 pipe. This action continues until the piston has reached the bottom of the cylinder, when the mandril 
 projects nearly its whole length through the bottom of the cylinder. 
 
 This was a great improvement on the old method of drawing, but yet accompanied with some objec- 
 tions, one of the most prominent being that, for small pipe, the mandril lacked stiffness to preserve itsell 
 from derangement, and the pipe in consequence was irregular in its thickness. 
 
 To obviate this, Hanson took out a patent in Aug., 1837, the principle of which was, that the mandril 
 was short, and instead of being fixed to the bottom of the piston or ram, as before, was fixed within 
 the cylinder, and a few inches from the die to a plate or diaphragm, stretched across the cylinder a 
 (fig. 3078). The mandril in this case being immovably fixed concentric with the die. To enable the lead 
 to arrive at the die and mandril, this diaphragm or “ bridge ” was perforated by four large holes, shown 
 in plan fig. 3079, through which the lead in a solid state was forced by the action of the ram, but united 
 again after passing the bridge and before reaching the die and mandril poiut. 
 
 By this means, it is true, the irregularity of the action of the man- 
 dril in Burr’s plan was avoided, but at a great expense of power, and 
 the pipe made was inferior, the lead not uniting after passing the 
 bridge so perfectly, but that the pipe manufactured by this machine 
 would split at the points corresponding to the divisions of the “ bridge.” , 
 To overcome this difficulty, as well as that of Burr’s, was the object 
 of the patent of Tateham, dated Oct., 1841, in which the piston is 
 truly bored from end to end, and a larger mandril or shaft (fig. 3080) 
 fitted within, nearly of the length of the cylinder, into the bottom of 
 which is fixed the short core or mandril for the bore of the pipe, the 
 mandril remaining as in Hanson’s plan, fixed just within the die. 
 
 As the hollow piston descends* upon the lead (the mandril shaft 
 rising meanwhile within it), the latter is forced around the shoulder of 
 the mandril, and so through the die into pipe. 
 
 At first sight, and in model, this plan would appear to he very effec- 
 tual, but in practice it is attended with some objections, the principal 
 of which is the difficulty of preserving the smooth, and at the same 
 time tight action of the hollow piston, and the mandril shaft moving 
 within ir. 
 
 It will be readily foreseen that the great power necessary for the 
 manufacture of pipe, will force the lead between the mandril shaft and 
 the bore of the piston, increasing the friction to a very great extent. 
 
 Cornell’s improvements consist simply in making the pipe from that 
 action of the power, and not to move the mass of compressed lead 
 through the cylinder to the die. This is effected by making the piston or ram a die holder, and hollow, 
 and affixing the mandril to the bottom of the cylinder, and extending it to the die in the piston bottom 
 (fig. 3081). The effect is evident. 
 
 The instant the piston commences its movement, pipe is formed a t the die, at one half the expenditure 
 of power necessary when the mass of lead is moved through the cylinder. 
 
 PISE-WOBK. A method of constructing very durable walls of kneaded earth. Any kind of earth 
 that will sustain itself with a small slope, is adapted to the purpose ; but that best suited to it is clay, 
 containing small gravel of sufficient consistence to be dug with a spade. It is first well beaten, then 
 screened to separate stones larger than a common hazel nut ; after which, it is wetted sufficiently to 
 enable it to retain the form given to it by kneading between the fingers. It is now fit for use, and in 
 applying it to build a wall, a sort of movable box or mould is made for the intended wall, of deal planks 
 put together with their joints ploughed, and tongued, and strengthened with clamps on the outside. 
 These frames rest on cross pieces or putlocks, which pass through the thickness of the wall, and near 
 the ends are mortices, into which are placed upright pieces, secured by wedges at the bottom, and tied 
 with ropes. These uprights are set to the intended thickness of the wall, which is about £0 inches at 
 bottom, and gradually diminishes upwards. The frames are steadied at the top by means of cross 
 sticks or struts, and the ropes are made tight by twisting them with a small piece of wood placed be- 
 tween the folds. The frames being properly fixed, the earth is thrown in, and worked like concrete or 
 mortar ; to allow the putlocks to be readily withdrawn, the parts about them must be well wetted. 
 
 In commencing a wall, the first frame is put at one of the extremities, and the end of the frame closed 
 by planks secured by iron cramps ; at the other part, where there is no end, the wall is to be sloped off 
 at an angle of about 60°, for facility in joining on the next piece. In commencing the work, the bottom 
 being well cleaned and sprinkled with water, the laborers bring the masons the prepared earth, and 
 tread it with their feet into a bed 3 or 4 inches thick ; they then ram it down with a rammer. In ram- 
 
 * Tor convenience, we assume that the piston descends in all these machines, as it matters butlittle iD elucidating 
 the principle whether the piston descends or the cylinder ascends, but the former method is more easily compre- 
 hended. • 
 
 
 part of the lead subjected to the 
 
PLANES AND PLANING MACHINES. 
 
 497 
 
 ming, it is turned round at each stroke, so as to make the work more compact, and unite it with tha 
 previously done. By means of the rammer, the first layer is reduced in thickness about one half, and 
 on this compressed bed another layer is spread out, and beaten in the same manner, and so on, until the 
 case is filled. The frame is then taken down, and moved further on, so that the plank entirely covers 
 the inclined part. Lintels are placed over all the apertures, and the finished portions are left for some 
 months to dry. The surface may then be coated with plaster, and the wall is finished. 
 
 Cob walls, as they are termed in Devonshire, resemble pise-work ; they are formed of clay, loam, and 
 chopped straw, and are generally 2 feet thick, resting on brick or stone foundations, 3 or 4 feet above 
 the level of the soil ; they must he carried up at several times, and not he hurried. After each addition 
 the sides are carefully pared down with an iron cob parer, which resembles a baker’s peel. When dry, 
 it is coated with fine stucco or plaster, and if kept dry at its top and foundation, it is very durable. 
 
 Walls similar to pise-work are sometimes made in this country with cement of lime or cement mor- 
 tar, and small stones or screenings; the interior plastering being laid directly on the walls, the outer 
 being usually left in its rough cast state ; the timbers for the floors are inserted as the wall progresses. 
 
 PISTOL. See Gun. 
 
 PISTON. See Pump — Engine, etc. 
 
 PLANES AND CHISELS.'* If we drive an axe, or a thin wedge, into the centre of a block of wood, 
 it will split the same into two parts through the natural line of the fibres, leaving rough uneven surfaces, 
 and the rigidity of the mass will cause the rent to precede the edge of the tool. The same effect will 
 partially occur, when we attempt to remove a stout chip from off the side of a block of wood with the 
 hatchet, adze, paring or drawing knife, the paring chisel, or any similar tool. So long as the chip is 
 too rigid to bend to the edge of the tool, the rent will precede the edge ; and with a naked tool, the 
 splitting will only finally cease, when the instrument is so thin and sharp, and it is applied to so small a 
 quantity of the material, that the shaving can bend or ply to the tool, and then only will the work be 
 cut, or will exhibit a time copy of the smooth edge of the instrument, in opposition to its being split or 
 rent, and consequently showing the natural disruption or tearing asunder of the fibres. 
 
 The axe or hatchet with two bevils, is intended for hewing and splitting, when applied to paring the 
 surface of a block, must he directed at the angle, which would be a much less convenient and less strong 
 position than that of the side hatchet with only one chamfer ; but for paring either a very large or a 
 nearly horizontal surface, the side hatchet in its turn is greatly inferior to the adze, in which the handle 
 is elevated at some CO or 70 degrees from the ground, the preference being given to the horizontal po- 
 sition for the surface to he wrought. The instrument is held in both hands, wLilst the operator stands 
 upon his work in a stoc 'ing position, the handle being from twenty-four to thirty inches long, and the 
 weight of the blade from two to four pounds. 
 
 The chisel admits of being very carefully placed, as to position, and when the tool is strong, very flat, 
 and not tilted up, it produces very true surfaces, as seen in the mouths of planes. The chisel when 
 applied with percussion, is struck with a wooden mallet, but in many cases it is merely thrust forward 
 by its handle. The paring-knife, exhibits also a peculiar but most valuable arrangement of the chisel, 
 in which the thrust obtains a great increase of power and control ; and in the drawing-knife, the narrow 
 transverse blade and its two handles form three sides of a rectangle, so that it is actuated by 'traction, 
 instead of by violent percussion or steady thru® 
 
 The chisel, when inserted in one of the several forms of stocks or guides, becomes the plane, the 
 general objects being to limit the extent to which the blade can penetrate the wood, to provide a defini- 
 tive guide to its path or direction, and to restrain the splitting in favor of the cutting action. In gene- 
 ral, the sole or stock of the plane is in all respects an accurate counterpart of the form it is intended to 
 produce. Although convex surfaces, such as the outside of a hoop, may be wrought by any of the 
 straight planes, applied in the direction of a tangent, it is obvious the concave plane would be more con- 
 venient. For the inside of the hoop, the radius of curvature of the plane, must not exceed the radius 
 of the work. For the convenience of applying planes to very small circles, some are made very narrow 
 or short, and with transverse handles, such as the plane for the hand-rails of staircases. The sections 
 of planes are also either straight, concave, convex, or mixed lines, and suited to all kinds of specific 
 mouldings, hut we have principally to consider their more common features, namely, the circumstances 
 of their edges and guides ; first, of those used for flat surfaces, called by the joiners bench planes , 
 secondly, the grooving planes ; and thirdly, the moulding planes. The various surfacing planes are nearly 
 alike, as regards the arrangement of the iron, the principal differences being in their magnitudes. Thus 
 the maximum width is determined by the average strength of the individual, and the difficulty of 
 maintaining with accuracy the rectilinear edge. In the ordinary bench planes the width of the iron 
 ranges from about 2 to 2^ inches j 
 
 The lengths of planes are principally determined by the degree of straightness that is required in the 
 work, and which may be thus explained. The joiner's plane is always either balanced upon one point 
 beneath its sole, or it rests upon two points at the same time, and acts by cropping off these two points, 
 without descending to the hollow intermediate between them. It is therefore clear, that by supposing 
 the work to he full of small undulations, the spokeshave, which is essentially a very short plane , would 
 descend into all the hollows whose lengths were less than that of the plane, and the instrument is there- 
 fore commonly used for curved lines. But the greater the length of the plane, the more nearly would 
 its position assimilate to the general line of the work, and it would successively obliterate the minor 
 errors or undulations ; and provided the instrument were itself rectilinear, it ivould soon impart that 
 character to the edge or superficies submitted to its action. The following table may be considered to 
 contain the ordinary measures of surfacing planes. 
 
 * Holtzapfel. 
 
 t The “ iron,” is scarcely a proper name for the plane-iron , which is a cutter or blade, composed partly of iros 
 end steel ; hut no confusion can arise from the indiscriminate use of any of these terms. 
 
 Vol. 11—32 
 
408 
 
 PLANES AND PLANING MACHINES. 
 
 Names of Planes. 
 
 Length 
 
 is it 
 
 i inches. 
 
 Width: 
 
 ; in inches. 
 
 Widths 
 
 of irons 
 
 Modelling Planes, like Smoothing Planes 
 
 1 
 
 to 
 
 5 — 
 
 4 
 
 to 
 
 2 
 
 — 8-16 
 
 to 
 
 11 
 
 Ordinary Smoothing Planes . 
 
 6* 
 
 to 
 
 8 — 
 
 2* 
 
 to 
 
 8 4 
 
 — 14 
 
 to 
 
 24 
 
 Rebate Planes . .... 
 
 
 
 »4 - 
 
 “1 
 
 to 
 
 2 
 
 — 4 
 
 to 
 
 2 
 
 Jack Planes ..... . 
 
 12 
 
 to 
 
 IT — 
 
 24 
 
 to 
 
 3 
 
 — 2 
 
 to 
 
 2J 
 
 Panel Planes ..... 
 
 144 
 
 
 — 
 
 ?4 
 
 
 
 - 24 
 
 
 Trying Planes .... . . 
 
 20 
 
 to 
 
 22 — 
 
 84 
 
 to 
 
 35 
 
 — 24 
 
 to 
 
 44 
 
 Long Planes ....... 
 
 24 
 
 to 
 
 26 - 
 
 84 
 
 
 
 — 24 
 
 
 Jointer Planes ....... 
 
 28 
 
 to 
 
 80 — 
 
 34 
 
 
 
 - 34 
 
 
 
 Cooper’s Jointer Planes ..... 
 
 . CO 
 
 to 
 
 T2 — 
 
 5 
 
 to 
 
 54 
 
 - 34 
 
 to 
 
 31 
 
 The succession in which they are generally used, 
 
 is the jack plane for 
 
 Ihe coarser w 
 
 ork, the 
 
 trying 
 
 plane for finer work and trying its accuracy, and the smoothing plane for finishing. 
 
 The mouth of the plane is in the narrow aperture between the face of the iron, and the wear, or face of 
 the mortise; the angle between these should be as small as possible, in order that the wearing away 
 of the sole, or its occasional correction, may cause but little enlargement of the mouth of the plane ; at 
 the same time the angle must be sufficient to allow free egress for the shavings, otherwise the plane is 
 said to choke. In all the bench planes the iron is somewhat narrower than the stock, and the mouth is 
 a wedge-formed cavity ; in some of the narrow planes the cutting edge of the iron extends the full 
 width of the sole, as in the rebate plane. 
 
 The amount of force required to work each plane is dependent on the angle and relation of the edge, 
 »n the hardness of the material, and on the magnitude of the shaving; but the required force is in 
 addition greatly influenced by the degree in which the shaving is bent for its removal in the most perfect 
 manner. The spokeshave cuts perhaps the most easily of all the planes, and it closely assimilates to 
 the penknife ; the angle of the blade is about 25 degrees, one of its planes lies almost in contact with 
 the work, the inclination of the shaving is slight, and the mouth is very contracted. The spokeshave 
 works very easily in the direction of the grain, but it is only applicable to small and rounded surfaces, 
 and cannot he extended to suit large flat superficies, as the sole of the plane cannot be cut away for 
 such an iron, and the perfection of the moutii is comparatively soon lost in grinding the blade. Plane 
 irons are usually ground at the angle of 25'°, and sharpened on the more refined oilstone at 35°, so as to 
 make a second bevil or slight facet ; the irons so ground are placed at the angle of 45°, or that of 
 common pitch ; it therefore follows, that the ultimate bevil, which should he very narrow, lies at an ele- 
 vation of 10° from the surface to be planed. In the planes with double irons, the top iron is not intended 
 to cut, but to present a more nearly perpendicular wall for the ascent of the shavings, the top iron more 
 effectually breaks the shavings, and is thence sometimes called the break- iron. Now therefore, the shav- 
 ing being very thin, and constrained between two approximate edges, it is as it were bent out of the 
 way to make room for the cutting edge, so that the shaving is removed by absolute cutting, and without 
 being in any degree split or rent off. 
 
 Some variation is made in the angles at which plane irons are inserted in their stocks. The spoke- 
 shave is the lowest of the series, and commences with the small inclination of 25 to 30 degrees ; and 
 the general angles, and purposes of ordinary planes are nearly as follows. Common pitch, or 45 de- 
 grees from the horizontal line, is used for all the bench planes for deal and similar soft woods. York 
 pitch, or 50 degrees from the horizontal, for the bencWdanes for mahogany, wainscot, and hard or 
 stringy woods. Middle pitch, or 55 degrees, for mouldmg-planes for deal, and smoothing planes for 
 mahogany, and similar woods. Half pitch, or 60 degrees, for moulding planes for mahogany, and 
 woods difficult to work, of which bird’s-eye maple is considered one of the worst. 
 
 Boxwood, and other close hard woods, may be smoothly scraped, if not cut, in any direction of the 
 grain, when the angle constituting the pitch entirely disappears ; or with a common smoothing-plane, 
 in which the cutter is perpendicular, or even leans slightly forward ; this tool is called a scraping plane , 
 and is used for scraping the ivory keys of piano-fortes, and works inlaid with ivory, brass, and hard- 
 woods ; this is quite analogous to the process of turning the hard woods. The cabinet-maker also em- 
 ploys a scraping-plane, with a perpendicular iron, which is grooved on the face, to present a series of 
 fine teeth instead of a continuous edge; this, which is called a toothing plane, is employed for roughing 
 and scratching veneers, and the surfaces to which they are to be attached, to make a tooth for the better 
 hold of the glue. The smith’s-plane for brass, iron, and steel, has likewise a perpendicular cutter, 
 ground to 70 or 80 degrees ; it is adjusted by a vertical screw, and the wedge is replaced by an end 
 screw and block. 
 
 It is well known that most pieces of wood will plane better from the one end than from the other, and 
 when such pieces are turned over, they must be changed end for end likewise. The plane working with 
 the grain, would cut smoothly, as it would rather press down the fibres than otherwise ; whereas, against 
 the grain , it would meet the fibres cropping out, and be liable to tear them up. The workman will ap- 
 ply the smoothing-plane at various angles across the different parts of such wood according to his judg- 
 ment ; in extreme cases, where the wood is very curly, knotty, and cross-grained, the plane can scarcely 
 be used at all, and such pieces are finished with the steel scraper. This simple tool was originally a 
 piece of broken window-glass, and such it still remains in the hands of some of the gun-stock makers ; 
 hut as the cabinet-maker requires the rectilinear edge, he employs a thin piece of saw-plate. The edge 
 is first sharpened at right angles upon the oilstone, and it is then mostly burnished, either square or at 
 a small angle, so as to throw up a trifling burr, or wire-edge. The scraper is held on the wood at about 
 60°, and as the minute edge takes a much slighter hold, it may be used where planes cannot be well 
 applied. The scraper does not work so smoothly as a plane in perfect order upon ordinary wood, and 
 as its edge is rougher and less keen, it drags up some of the fibres, and leaves a minute roughness, 
 interspersed with a few longer fibres. 
 
 We may plane across the grain of hard mahogany and boxwood with comparative facility, as the fibres 
 are packed so closely, like the loose leaves of a book when squeezed in a press, that they may b» cut in 
 
PLANES AND PLANING MACHINES. 
 
 499 
 
 nil directions of the grain with nearly equal facility, both with the flat and moulding planes. But the 
 weaker and more open fibres of deal and other soft woods, cannot withstand a cutting edge applied to 
 them parallel with themselves , or laterally, as they are torn up, and leave a rough unfinished surface. 
 The joiner uses therefore, for deal and soft woods, a very keen plane of low pitch, and slides it across 
 obliquely, so as to attack the fibre from the one end, and virtually to remove it in the direction of its 
 length ; so that the force is divided and applied to each part of the fibre in succession. The moulding 
 planes cannot be thus used, and all mouldings made in deal, and woods of similar open soft grain, are 
 consequently always planed lengthways of the grain, and added as separate pieces. As however many 
 cases occur in carpentry, in which rebates and grooves are required directly across the grain of deal, the 
 obliquity is then given to the iron , which is inserted at an angle, as in the skew-rebate and fillister, and 
 the stock of the plane is used in various ways to guide its transit. 
 
 Moulding planes. — All the planes hitherto considered, whether used parallel with the surfaces as in 
 straight works, or as tangents to the curves as in curved works, are applied under precisely the same 
 circumstances as regards the angular relation of the mouth, because the edge of the blade is a right 
 line parallel with the sole of the plane ; but when the outline of the blade is curved, some new condi- 
 tions arise which interfere with the perfect action of the instrument. It is now proposed to examine 
 these conditions in respect to the semicircle, from which the generality of mouldings may be considered 
 to be derived. 
 
 A small central portion may he considered to he a horizontal line ; two other small portions may be 
 considered as parts of vertical dotted lines, and the intermediate parts of the semicircle merge from the 
 horizontal to the vertical line. 
 
 The reason why one moulding plane figui-ed to the half-round cannot, under the usual construction, 
 be made to work the vertical parts of the moulding with the same perfection as the horizontal, exists in 
 the fact, that whereas the ordinary plane iron presents an angle of some 45 to 60 degrees to the sole of 
 the plane, which part is meant to cut, it presents a right angle to the side of the plane, which part is 
 not meant to cut. Thus if the parts of the iron of the square rebate plane, which protrude through 
 the sides of the stock, were sharpened ever so keenly, they would only scrape and not cut, just the same 
 as the scraping plane with a perpendicular iron. When, however, the rebate plane is meant to cut at the 
 side, it is called the side-rebate plane, and its construction is then just reversed, that is, the iron is in- 
 serted perpendicularly to the sole of the plane, but at an horizontal angle, or obliquely to the side of the 
 plane, so that the cut is now only on the one side of the plane, and which side virtually becomes the 
 sole. A second plane sloped the opposite way, is required for the opposite side, or the planes are made 
 in pairs, and are used for the sides of grooves, and places inaccessible to the ordinary rebate plane. 
 The square rebate plane, if applied all around the semicircle, would be everywhere effective so long as 
 its shaft stood as a radius to the curve, as then the angle of the iron would be in the right direction in 
 each of its temporary situations. But in this mode a plane to be effective throughout, demands either 
 numerous positions of the plane, or an iron of such a kind as to combine these several positions. The- 
 oretically speaking therefore, the face of the cutter suitable to working the entire semicircle or bead, 
 would become a cone, or like a tube of steel bored with a hole of the same diameter as the bead, turned 
 at one end externally like a cone, and split in two parts. 
 
 As all the imperfections in the actions of moulding -planes occur at the vertical parts, there is a gen- 
 eral attempt to avoid these difficulties by keeping the mouldings flat, or nearly without vertical lines. 
 For example, concave and convex planes, called hollows and rounds , include generally the fifth or sixth, 
 sometimes about the third of the circle ; and it is principally in the part between the third and the 
 semicircle that the dragging is found to exist ; and therefore, when a large part of the circle is wanted, 
 the plane is applied at two or more positions in succession. In a similar manner large complex mould- 
 ings often require to be worked from two or more positions with different planes, even when none of 
 their parts are undercut, but in which latter case this is of course indispensable. And in nearly all 
 mouldings the plane is not placed perpendicularly to the moulding, but at an angle so as to remove all 
 the nearly vertical parts, as far towards the horizontal position as circumstances will admit. 
 
 Planing Machines for Wood. — In using hand-tools, the instrument rests immediately upon the face 
 of the work under formation ; and in repeating any one result, the same careful attention is again re- 
 quired in every successive piece. But in the machines acting by cutting, the accuracy is ensured far 
 more readily, by running either the work or the tool, upon a straight slide, an axis, or other guide, the 
 perfection of which has been carefully adjusted in the first formation of the machine ; and the slide or 
 movement copies upon the work, its own relative degree of perfection. The economy of these applica- 
 tions is therefore generally very great, and they are frequently most interesting, on account of the 
 curious transitions to be observed from the hand-processes to the machines, in some cases with but little, 
 in others with considerable change in the general mode of procedure. 
 
 The first planing machine for wood is supposed to have been that invented by General Bentham, 
 who took out a patent for it in 1791 ; it was based on the action of the ordinary plane, the movements 
 of which it closely followed. This contrivance reduced the amount of skill required in the workman, 
 but not that of the labor ; it appears to have been but little used. The board to be planed was some- 
 times laid on a bench, at other times fixed by long cheeks having teeth, which penetrated its edges ; the 
 iron of the plane extended the full width of the board, and the stock of the plane had slips to rest on 
 the bench and check the cutting action, when the board was reduced to the intended thickness. 
 
 For feather-edged boards, the two slips were of unequal thicknesses; for those intended to be tape* - 
 in their length, the guide rails had a corresponding obliquity, and were fixed to the bench. The plane 
 was moved to and fro by a crank, it was held down to its work by weights, and the plane was lifted up 
 in the back stroke to remove the friction against the cutter. 
 
 The scale-board plane, abbreviated into scabbard-plane, for cutting off the wide chips used for making 
 hat and bonnet boxes, is in like manner, a plane exceeding the width of the board ; it is loaded with 
 
PLANES AND PLANING MACHINES 
 
 500 
 
 weights, and dragged along by a rope and windlass, the projection of the iron determines the thicknesi 
 of each shaving or scale-hoard. This construction is also reversed, by employing a fixed iron, drawing 
 the wood over it, and letting the scale-hoard descend through an aperture in the bench ; each of these 
 modes is distinctly based on the common plane. 
 
 The late Mr. Joseph Bramah took out a patent in 1802 fora planing machine for wood; one of which 
 may he seen in the Gun Carriage Department, Woolwich Arsenal. The timber is passed under a large 
 horizontal wheel, driven hy the steam engine at about ninety revolutions per minute ; the face of tint 
 wheel is armed with a series of twenty-eight gouges, placed horizontally and in succession around it ; 
 the first gouge is a little more distant from the centre, and a little more elevated than the next, and sc 
 on. The finishing tools are two double irons, just like those of the joiner, but without the advantage 
 of the mouth. 
 
 In France, planing machines for wood were patented as early as 1817-18 hy M. Roquin, and M. 
 Manneville in 1835. The first was intended for planing, grooving, and tonguing, and moulding for the 
 purpose of ornamant. The Board was placed on a platform or caariage, adjustable by screws to suit 
 different thicknesses, to which the boards or planks are desire to be reduced. The planes were “ cylin- 
 drical rotating planes.” In Manneville’s, feed rollers were introduced, and the tonguing and grooving 
 was performed by circular saws. 
 
 In this country the most successful machine for planing wood, is the invention of Mr. Woodworth, 
 patented in 1828, and reissued in 1845 ; it consisted of a rotary cylinder on which were fastened the 
 blades or cutters, placed above or laterally to a carriage on which wjis placed the board to be planed, 
 which was moved forward by rack and pinion. The cylinder revolved opposed to the movement of the 
 board, and rollers were introduced bearing upon the upper surface, so as to prevent the board being 
 drawn up to the cutter. The following is the claim of the reissue patent : 
 
 “What is claimed therein as the invention ofWm. Woodworth, deceased, is the employment of rotary 
 planes substantially such as herein described, in combination wdth rollers, or any analogous device to 
 prevent the boards from being drawn up by the planes, when cutting upwards ; or from the reduced oi 
 planed to the unplaned surface as described’’ 
 
 And afterwards, 
 
 “ The effect of the pressure rollers in these operations, being such as to keep the boards, etc., steady, 
 and prevent the cutters from drawing the boards towards the centre of the cutter wheels, whilst it is 
 moved through hy machinery. In the planing operation the tendency of the plane is, to lift the boards 
 directly up against the rollers ; but in the tonguing and grooving the tendency is to overcome the fric- 
 tion occasioned by the pressure of the rollers.” 
 
 Woodworth also united the tonguing and grooving machine to the planer, by which both operations 
 were performed at one and the same time. 
 
 Woodworth’s planer has been a fruitful source of litigation. The only novelty seems to have been in 
 the pressure rollers to keep down the board, and the union of the tonguing and grooving with the planing. 
 
 Previous to the machine of Woodworth, Hill's machine was constructed, consisting of a rotaiy cutter 
 similar to Woodworth’s, but placed beneath the bench ; the board was pressed down on the bench by 
 means of rollers ; in this machine boards were planed but not reduced to an uniform thickness. To 
 obviate this, an improvement was made on this machine in 1850 by N. G. Norcross. He has made 
 the cutting cylinder movable, vertically, which it was not before, and has connected it with his rest, 
 that is with the pressure roller, so that when the latter is forced upwards by the increased thickness of 
 the board, it draws the cutter upwards with it, which thereby is made to cut just as much more from 
 the under side of the board, as the roller is pressed up by the increased thickness. By this con- 
 contrivance the edge of the cutter is kept in a fixed relation to the rest, or in other words, the pres- 
 sure roller, the space between them being always the same, whereas in Hill’s, and also in Woodworth’s 
 the edge of a knife had a fixed rotation to the bed, and not to the pressure roller. To obviate the use of 
 the rotary cutter and continuous feed, which by many were supposed to be inventions of Woodworth and 
 covered by his patent, many machines with stationary cutters or planes were made, beneath which 
 the board to be planed was forced, one of which is here introduced ; but the rotary cutter is by 
 far the simplest and most economical in regard to power. The Woodworth planer still continues to 
 be the one in common and general use for the planing of boards or thin plank, but for the planing 
 of timber, the Daniells’ planer is generally preferred. This machine consists essentially of two arms 
 revolving parallel with the face of the timber to be planed, near the extremities of which are inserted 
 two narrow planes or gouges, the timber lies upon a carriage, and the feed is effected by a rack and 
 pinion. Upon the shaft to which the arms are attached, is a long drum or pulley, to which motion 
 is given by means of a narrow belt; the shaft can be raised or depressed, even whilst the machine 
 is in operation, by which means a thinner or thicker chip or shaving may be taken off, or successive 
 shavings may reduce the timber to the thickness required. A machine somewhat similar to this, is 
 sometimes used for the planing of iron, but it does not leave a finished surface. 
 
 Tonguing and grooving is usually performed by revolving cutters; the cutter irons being generally 
 of the hook form or duck bill. The same form of cutter is used in setting mouldings ; they are roughed 
 by cutters and then forced through stationary irons with cutting edges, corresponding in form to the 
 moulding required. Wave mouldings, such as are used in cars and on furniture, are finished on a 
 machine somewhat similar to the iron planer, the wave motion being given by a pattern on the carriage, 
 which in its passage vibrates an arm connected with the tool. 
 
 Planing Machine , Wood. J. P. Woodbury’s patent. A Fig. 3076 is the frame that contains the 
 machinery. B is the travelling platform, which is formed of lags, and linked together similar to some 
 of the well-known horse powers, the upper part of which runs on ways or rollers, which sustain it per- 
 fectly level. C is the rollers over the platform, which serve to aid the lower platform to carry the 
 board under the stationary cutters. D is the pulley where the power is to be applied to drive the boar£ 
 
PLANES AND PLANING MACHINES. 
 
 501 
 
 through the machine. 
 
 It operates and turns the chain-wheels and shafts M, thereby moving the 
 platform, and making an endless feeding power. E is the stocks 
 or cast-iron beds to which the cutters are attached. Said cutters 
 are similar to those of a common plane, and are firmly screwed 
 to the beds which extend across the machine, and attached at 
 each end to the cast iron frame G, where they are each ad- 
 justed and held by set-screws. F is the yielding-bar mouth- 
 piece, which also extends across the machine, and is held 
 down by springs under the same. This bar is as near the cut- 
 ting edge as possible, and it serve? to hold the grain of the 
 wood together just at the cutting edge, which wholly prevents 
 splitting or tearing the wood. It adapts itself to the ine- 
 qualities of the board or plank without clogging, and thereby 
 produces a perfect surface. G is the frame that holds the 
 cutters, stocks, and mouth-pieces in their proper places, and 
 is to be raised or lowered to suit the different thicknesses of 
 material. H is the crank with the geering attached to raise 
 and lower the frame G, which holds the cutters. I is the 
 geer-wheels. that connect the feeding rollers C to the endless 
 travelling platform B. J is a series of rollers, which hold 
 the board over the cutters, to plane the under side of the 
 board, if required. L is a wheel attached to a screw to 
 move a horizontal slide on which rests the frame that holds 
 the rollers J, and to which is attached four wedges. The 
 wheel and screw L move the horizontal slide, thereby raising 
 and lowering the rollers to admit of different thicknesses of 
 material. M is the chain-wheels on which the endless plat- 
 form revolves. The board is entered between the platform 
 B and the rollers C, and carried through under the station- ' 
 ary cutters E, which plane and reduce the board to a uniform 
 thickness. It then moves forward between the rollers J 
 and under the cutters K, which plane the under side, if re- 
 quired. » 
 
 The above described machine produces a most excellent 
 surface, and does the work with great rapidity. 
 
 The patent includes planing, tonguing, and grooving ma- 
 chinery. 
 
 Machines for Planing Iron. 
 
 Planing Machine, Hand. The following figures represent 
 three views of the machine: Fig. 3077 is a front .elevation, 
 Fig. 3078 is a side elevation, and Fig. 3079 a plan. The 
 same parts are denoted -by the same letters in all the figures. 
 
 A A the supporting legs of the machine, on which rests B 
 B the bed frame. To this is bolted the upright frame for 
 carrying the slides. 
 
 C, the vertical slide. On this are cast profecting pieces 
 a, through which the carrying screws f f pass. By these 
 screws the slide is raised and depressed at pleasure by the 
 geering at their upper extremities. 
 
 D, the horizontal slide, which is carried across the slide C 
 by a screw h b, which has its bearings in the slide c c, which 
 
 , ,k \ j has between it and D a slide-carrier d d, admitting of a 
 
 \1 small amount of circular motion on the stud-bolts h h. These 
 
 pass through circular slots in the plate, and are provided 
 with pinching-nuts to retain the slide in the position desired. 
 By this provision the slide may be set at any required 
 angle, as iu other planing machines. In front of the cutter-slide is placed the tool-box e and g, to which 
 is fixed the cutting-tool in the usual way. This slide is moved by the hand-wheel on the upper end of 
 the slide-screw k ; but the motion of the cross-slide D is obtained by a self-acting apparatus from E E, 
 the travelling table. On this the article to be planed is fixed by bolts, sliding in dovetailed grooves in 
 the usual way. 
 
 F, the driving-pinion which geers into the rack M on the under side of the travelling table E. This 
 pinion is keyed on the end of G the driving-shaft, on one end of which is the driving-pinion F, and on 
 the other H a hand-cross, keyed on the end of the shaft G for working the pinion F, which travels the 
 work-table E by means of the rack M attached to its under side. 
 
 K, a ratchet-wheel fast on one end of the slide-screw b b. 
 
 L, a fclick working in the ratchet-wheel K. This click is guided in the length of its travel at each 
 stroke by the position of the sliding-studs in the pieces m. and n, which are connected by the rod r. 
 The studs slide in grooves in the pieces m and n, and can therefore be set at any required distances 
 from the centres of motion ; and accordingly, the number of teeth over which the click is carried de- 
 pending upon the positions of the studs, the amount of feed-motion of the screw b b can be regulated 
 at pleasure. 
 
502 
 
 PLANING MACHINE, HAND. 
 
PLANING MACHINE. 
 
 503 
 
 M, the travelling rack, made fast to the table and worked by the pinion F. The form of the rack is 
 shown in transverse section in Fig. 30*77, and an elevation and plan are shown in Figs. 3078 and 3079. 
 
 o, a balance-weight on the end of a lever projecting from the same small shaft on which the crank’ 
 ever is fixed. On the opposite end of this small shaft is fixed another lever, placed so that it is depressed 
 by the tapet S, when the travelling table is moved towards the back of the machine ; by this the crank- 
 lev er n is depressed and the weight o raised at the same instant. 
 
 S is a tapet on the travelling table, and which may be shifted to any required position and fixed there 
 by a pinching-screw with which it is provided. The position of this tapet is regulated according to the 
 length of the travel of the table at the time. 
 
 3079. 
 
 V V Y V, four hovel-wheels, geered pair and pair, for turning the screws// to raise or lower the 
 vertical slide C 0, to suit the work upon the table. Two of the wheels are fast upon the upper ends ol 
 the screws, and two are in like manner made fast on W a cross-shaft, on which are two of the bevel- 
 wheels V V for working the elevating screws//. This shaft has a square at one end to receive the eye 
 of a crank-handle or hand-wheel. It has its bearings in two bored pieces which rest on the upper ends 
 of the screws, and against the eyes of the wheels keyed on them, and are retained in their places by 
 check-pins in the usual way. 
 
 PLANING- MACHINE, by Archibald Mylne, Glasgow. This machine has some peculiarities which 
 render it worthy of a place among the higher order of tools of the same kind. 
 
 Fig. 3080 is a side elevation, and Fig. 3080 2 a front elevation of the entire machine, with the same 
 references. 
 
 I; is the bed- frame of the machine, carried on legs or supports i. The bed-frame is formed of one 
 casting, with two projecting edges of a shape, which are planed true, and fitted to corresponding 
 V-shaped grooves in the under side of the travelling table m, contrary to the usual arrangement in plan- 
 ing machines. 
 
 F is the upright frame for carrying the slides ; and m the sliding table for carrying the work to be 
 planed. The work is fixed to the table by bolts with dovetail heads, which slide in grooves of corre- 
 sponding form, running the length of the table. The upright frame F is formed of two side brackets 
 bolted down to strong flanges cast on the bed-frame k, and joined together at top by a cross-piece, which 
 gives to the frame the necessary rigidity and, strength. The faces of these cheeks and cross-piece are 
 planed true and polished. This is requisite in respect of the vertical faces, as upon these the vertical 
 slide a a moves when it is elevated and depressed by its screws n u ; and the cross-piece is polished to 
 avoid unseemly contrast of appearance. 
 
 A is the driving-belt for the forward motion of the table, passing round a large pullev, as shown m 
 Fig. 3080. . F 1 
 
 B, a cross-belt driving a smaller pulley for the return motion of the table, which is thus made quicker 
 than the forward motion. These belts can be shifted from fast to loose pulleys, as may be observed by 
 Fig. 3080, in which they are shown upon their loose pulleys. 
 
 D, a pinion fast on the pulley-shaft. 
 
 E, a wheel driven by the pinion D, and keyed fast on a shaft which passes through the bed-frame of 
 the machine, and carries the two fast pinions which give motion to the sliding-table by geering into 
 racks on the under side of it, shown in the end elevation. These two racks (or double rack) have the 
 teeth of the one opposite the space of the other, so as to render the motion smooth and uniform. 
 
 nn\ Fig. 3079, are tapets to reverse the motion of the table. 
 
 g, a double lever keyed on a hollow shaft which works freely on the driving-shaft. 
 
 •*7 Fig. 3079, a rod having one end attached to a lever, fast on the same shaft with the lever t, which 
 carries the weights r r , and has its other end attached to a lever keyed on the same hollow shaft with 
 double lever g. 
 
 M, a traverse-shaft connected by a lever with the shaft to which the lever / : s attached. 
 
PLANING MACHINE. 
 
 50 1 
 
 J, a lever fast on the shaft M ; and C, Fig. 30 80 2 , a guide for the belts connected with the lever J 
 which has one of its ends flat to prevent it from turning round, and at the same time to allow it to slir 
 lengthwise and shift the belts from the fast to the loose pulleys. 
 
 'The machine is set in motion by moving the belt-guide towards the off-side of the machine, by which 
 ttie belt is shifted on the narrow pulley, which is the driver. The sliding table is thus put in motion, 
 ana moves towards the back part of the machine, until the tapet n, catching one of the legs of the 
 
 lever g, turns it over, throwing outward the weight r, by the connecting-rod x, which is worked by a 
 rever fast on the hollow shaft with g. 
 
 The weights r r'. and lever t, being fast on the same shaft and connected by a link with M, the whole 
 
PLANING MACHINE. 
 
 505 
 
 s simultaneously put in motion, and the upper weight r being thrown off the balance, the belt-guide is 
 pulled by the lever J until the belt A is shifted to the loose pulley, and the cross-belt B to the fast 
 pulley, to produce the return motion. On the return of the table the tapet n' turns over the lever g 
 in the opposite direction, and the reversing motion is produced in the same manner. The tapet n' 
 stands further out than n, so that each of them can only touch one leg of the lever g. They are alsa 
 made to slide in dovetail grooves, and have pinching screws to fix them, to suit the length of work and 
 its position on the table. 
 
 The lever t, which moves with the weights r r', communicates motion to the slides on the frame F, 
 A section of these slides is shown at Fig. 3081, and detached parts in Figs. 3082 to 3086, the same let- 
 ters being used to denote the same parts on all the figures. 
 
 a, the vertical slide attached to the upright frame of the machine by four screwed pins, which pass, 
 pair and pair, through long grooves in the cheeks of the frame F, and the slide being set at the requisite 
 height by the screws uu, it can then be tightened by jam-nuts on the ends of the pins against the faces 
 of the frame, and retained in the required position. 
 
 b, the cross-slide which moves across the breadth of the machine, upon the face of the vertical slide a. 
 Motion is communicated to it by a screw which has its bearings ss in the ends of the vertical slide, and 
 which passes through a nut attached to the back of the slide b, as shown in Fig. 3081. The slide is 
 guided, and also securely retained, on the slide a by dovetail faces formed on the back, and which 
 correspond to dovetails formed on a. The upper dovetail is made adjustable, Fig. 3081, to allow for 
 any wear of the surfaces which may take place. On the face of the slide is a graduated arc to regulate 
 the setting of the slide-carriage c, which is attached to it by fixing screws and nuts, Fig. 3080. The 
 screws have dovetail heads, which slide in an annular groove, Fig. 3082, and pass through two holes in 
 the circular pieces cast on the edges of the carriage c. The bolts are put in from the back of the slide b 
 through a recess cast in it for that purpose. The carriage thus admits of being placed and set at any 
 required angle with the slide b, as shown by Fig. 3087, and the details of the mode in which this is 
 ell'ected is explained by Figs. 3082 and 3083, and partially by Figs. 3081 and 3080. 
 
 3081. 
 
 3082. 
 
 3083. 
 
 In the carriage, c is a screw with bearings at its two extremities, in the metal of the carriage. It is 
 kept from moving endways by a ruff on its upper end, over which passes a ring of malleable iron, fixed 
 to the carriage by screwed pins tapped into the metal. On the lower end of this screw is fixed a small 
 bevel-wheel, which geers with one of a pair checked and bolted together, so that motion cannot be 
 communicated to the one without the other being moved simultaneously in the same direction. The 
 second of the wheels geers with a similar wheel upon the rod qq , Fig. 3080’, and their common bearing 
 consists of the V-shaped groove formed by the backs of the wheels being placed against each other. 
 This groove is truly turned to fit the corresponding V-shaped edge of an annular recess cut in the 
 centre of the cross-slide b, (see sections, Figs. 3081 and 3082.) The purpose of this arrangement of 
 wheels will be explained presently. 
 
 On the face of the carriage c a projecting piece is cast, which is planed with dovetail edges, Fig. 3083, 
 to receive corresponding dovetails of the slide d, Fig. 3084. On the back of this slide is also fixed a nut 
 through which the screw in the carriage c passes, for the purpose of raising and depressing the slide, 
 especially when set obliquely, according to the circumstances of the work under operation. 
 
 e is a second slide-carriage in all respects similar to the carriage c, except that it is smaller. It is 
 attached to the slide d also by bolts with dovetail heads, which work in an annular groove in the face 
 of the slide d, and the ends of the bolts, which are screwed to receive the fixing nuts, pass through holes 
 in the projecting lugs cast on the edges of the carriage, which can thus be set at any required angle on 
 the face of the slide d. 
 
 The slide f is similar to that marked d, and is attached to the face of the carriage c in exactly the 
 same manner; and is, moreover, moved by the screw of its carriage, with which it is connected by a 
 nut, Figs. 3081 and 3086, to any position required within the range of its travel. The tool-box is 
 attached to this slide by a flexible joint, which is easily understood from Figs. 3081 and 3086. The use 
 ol the joint is to prevent the tool h from cutting during the returning of the work-table, which in this 
 arrangement of slides would be apt to injure the more delicate parts of the machine, and possibly the 
 work under operation, particularly as the return motion of the table is much too quick for cutting. Very 
 little moliou of the joint is required to allow the tool to clear the work. 
 
506 
 
 PLANING MACHINE, SELF-ACTING. 
 
 The mode of fixing the tool is by T-headed bolts and glands, as shown in Figs. 3080 and 3086. It 
 this last the tool and glands are removed, but the fixing bolts are dotted in their positions. 
 
 uu, screws revolving in the projecting ends of the top rail, and working into nuts on the back of the 
 slide a. 
 
 o, handle to turn the screws by means of a system of bevel-wheels, in order to raise or depress the 
 slide a to suit the work to lie planed, the slide a having fixing bolts to secure it to the planed faces oi 
 the frame at the required height. 
 
 w, a lever with a spring-catch which may be geered into the wheel y. 
 
 v, a rod connecting the lever t with the lever w. The spring-catch being in geer, the wheel y receives 
 motion from the lever t , and being geered with a pinion on the end of the cross slide-screw, which re 
 volves in bearings s s, it communicates its motion to the screw and cross-slide b. The amount of feed is 
 adjusted by shifting the studs in the slots of the levers t and w\ and the direction in which the slide is 
 wanted to be moved is regulated according as the spring-catch is geered above or below the axis of the 
 lever w. 
 
 3087. 
 
 3086. 
 
 3C35. 3084. 
 
 This self acting feeding motion is also communicated to the down cutting slide d by shifting the 
 pinion from the end of the screw to the end of the small shaft which works in the bearings q q , Fig. 308f> 
 On this shaft is a small bevel-wheel shown at Figs. 3081 and 3082, which is carried round by having a 
 key projecting into a groove continued the whole length of the shaft. This wheel is carried along the 
 shaft by a projecting piece on the slide b, Fig. 3082, and its motion is communicated to that on the end 
 of the slide-screw in c, Fig. 3081, by means of two similar intermediate wheels placed in slide 6, as 
 above described. 
 
 The front slide /is not commonly attached to planing machines; but it is valuable where work is tc 
 be done which requires two or three different angled surfaces to be planed, and which can be done with 
 this machine by arranging the slides before starting, no shift being afterwards required. 
 
 Fig. 3087 shows the slides set at different angles. 
 
 PLANING MACHINE, SELF-ACTING COMPOUND, by Nasmyth, Gaskeli. A Co. The machine 
 represented in Figs. 3088, 3089, 3090, and 3091 is remarkable for compactness and elegance of arrange- 
 ment, and for the accuracy and dispatch with which a description of work that, previously to the intro- 
 duction of such machines, could only be intrusted to the most expert and skilful mechanic, but which can, 
 by its means, be executed by workmen of the most ordinary capacity. It is especially applicable to the 
 finishing of the numerous small levers used in locomotive engine and tool-making, and is admirably 
 adapted, not only to the planing of the sides and edges of such levers, but also to the finishing of their 
 rounded ends, which otherwise could only be accomplished by the rude and tedious process of chipping 
 and filing. 
 
 Fig. 3088 is a side elevation of the machine. 
 
 Fig. 3089 is a view of the front end or face. 
 
 Fig. 3090, a general plan ; and 
 
 Fig. 3091, a transverse section through the principal working parts. 
 
 General description . — The frame upon which the machine rests, and which is used for the purpose of 
 raising it to a convenient height, is composed of two cast-iron cheeks A A, strengthened by flanges, and 
 held together at the lower end by two stay-rods a a. These frames are disposed at an angle to each 
 other, in order to give greater stability to the structure. The main body of the machine consists of a 
 cast-iron table or box B bolted to the frames by internal flanges, as shown in the section, Fig. 3091, and 
 on the upper side of this table are cast the bracket C, carrying the driving-spindle, and the rectangular 
 chamber D, furnished with bearings for the other working parts of the machine. The square cast-iron 
 sliding-bar E, which carries the tool-holder, is accurately planed, and fitted into a recess in the upper 
 portion of the piece D. It is of essential importance that the slide E should move accurately' and with- 
 out play in a rectilinear and horizontal direction, and for this purpose it is secured laterally by the 
 adjusting screws b b, and vertically by the wrought-iron plate or cover c, fixed to the frame by the six 
 countersink screws ddd. 
 
 On the front end of the square slide E is cast a flat rectangular plate, which serves as the fixed point 
 of resistance to the various motions of which the tool-box is susceptible. The first of these is a rotary 
 motion, which is impressed upon it by a toothed quadrant plate e, worked by an endless screw on the 
 axis f. This arrangement enables the workman to set the tool at any required angle to the work. On 
 the upper edge of that part of the tool-box marked F, is fixed a nut, through which works a screw g : 
 surmounted by a handle or small hand-wheel This screw is used for raising or depressing the tool, and 
 
PLANING-MACHINE, SELF-ACTING. 
 
 507 
 
 thereby adapting it to the diameter or height of the work to be executed, as well as for regulating the 
 depth of cut. The part G, which is thus acted upon by the screw g, is furnished with two parallel 
 cheeks accurately dressed on their internal surfaces, and fitted to receive the tool-holder li. The tool 
 itself is inserted into a square hole passing through the piece h, and fixed firmly to it by two pinching- 
 screws. The tool-holder h is so formed as to admit of a small amount of rotary motion round two 
 centre screws passing through the cheeks of the piece G, and by this means accidents arising from the 
 friction of the tool against the work in the return stroke are prevented. 
 
 The mode in which motion is communicated to the tool-box is as follows : The extremity of the 
 
 square slide E opposite to that on which the tool-box is fixed, is traversed by a longitudinal slot or 
 groove i, adapted for the reception of a bolt-head, as shown in the transverse section, Fig. 3091. The 
 projecting part of the bolt passes through a hole in the end of the connecting-rod H, the opposite end 
 of which is attached by another bolt tc a rectangular cast-iron piece I, fixed to the end of the driving- 
 spindle, and acting as a crank for converting the rotary into a rectilinear motion. The crank I is 
 traversed throughout its whole length by a slot i, the form of which, as well as of that in the slide E, is 
 shown in the section, Fig. 3091. By means of these slots the length of the stroke and the position w 
 the tool may be easily and accurately adjusted to suit the work, as will be sufficiently obvious by 
 inspection of Fig. 3088. The driving-spindle works in two bearings, one of which, as before mentioned, 
 is cast on the bed of the machine B, and tire other is formed in the extremity of a bracket bolted to the 
 eide of it. The velocity of the driving-spindle is varied and regulated by means of the cone-pulley J 
 anil fly-wheel K. 
 
 3088. 
 
 The planing of circular surfaces is effected, in this machine, by means of a hollow cylindrical cast-iron 
 Aiandrel L, Figs. 3091 and 3092, accurately turned and fitted into the body of the machine, the centre 
 being exactly under that of the square slide E. This mandrel is provided with a conical bearing on the 
 front end, and is traversed by a malleable iron bolt l, secured to its opposite extremity by a nut. The 
 head of the bolt l is formed into a cylindrical socket, into which, by means of a cotter, is fixed another 
 bolt, having two conical pieces mm, one of which is immovable, and forms part of the bolt, while the 
 other slides upon it, and is adjusted by means of the nut n. These pieces are used for the purpose of 
 fixing the work M, upon which the machine is to operate ; and from their conical form, adapt themselves 
 to any required diameter, so as to insure, without any trouble in setting, the concentricity of the outer 
 surface with the eye. 
 
 The motion of the mandrel L, with its appendages, is effected by means of the worm-wheel FT, which 
 is fixed to its inner end by a large circular nut screwed to the cast-iron mandrel itself, independently of 
 the bolt l, which passes through it. The worm-wheel N geers with an endless' screw on the horizontal 
 axis o, working in two bearings, oue of which is formed by a small malleable iron piece bolted to the 
 body of the machine D, and the other extends considerably beyond the table, and is supported by the 
 bracket O bolted to it, as shown in the section, Fig. 3091. The axis o, besides the self-acting mecha- 
 nism which we are about to describe, is provided with a handle, by which it can at pleasure be moved by 
 the attendant workman. The self-acting geer, which, in Fig. 3093, is shown detached from the machine, 
 consists of an eccentric P, fixed upon the driving-spindle, and by means of the rod pp, communicating a 
 reciprocating motion to the slotted lever Q, which motion is again conveyed by the rod r r to the 
 smaller slotted lever S. The centres of motion of these levers are respectively on the extremities of the 
 traverse screw v, which is used only in flat planing, and on that of the axis o, of the endless screw, and 
 on these centres they are fitted to move loosely without turning them. The slots which traverse the 
 levers are for the purpose of altering the feed to any required amount. The motion of the levers is 
 communicated to their axes by the double pawls q and s, which work respectively into the wheels R 
 and T, fixed upon their centres v and o. These wheels act in this case as ratchet-wheels, and from the 
 peculiar form given to the pawls, they may be made to move either backwards or forwards by simply 
 reversing the direction of the pawls. 
 
 For the purpose of planing flat surfaces with this machine, it is provided with a cast-iron face-plaia 
 G U, which is traversed by several slots, cast on its exterior surface, and adapted to receive the bolts 
 by which the work is to be fixed to it. The back of the face-plate is planed and fitted to move trans- 
 versely along the slide V, by means of adjustable dovetail pieces, in the manner we have already so 
 requently had occasion to describe. This motion is effected by means of the screw v, which is worked 
 
508 
 
 PLATE-BENDING MACHINE. 
 
 by the mechanism above described, and which, having a bearing at each end of the slide V, passei 
 along a recess cast in its surface, and works into a brass nut fixed on the back of the face-plate U. The 
 traverse screw v is provided with a handle w, for the purpose of setting the work into its proper position 
 under tire tool, before bringing the self-acting mechanism into geer. 
 
 noon. 
 
 PLATE-BENDING MACHINE, by Robert Napier, Glasgow. This species of machine, originally 
 confined to the tinsmith's shop, has recently — enlarged in its dimensions and rendered more complete in 
 its mechanism — become indispensable in the operations of boiler-making and iron-ship building, in whicti 
 plates are required to be bent to various degrees of curvature. The example given is the design of Mr. 
 Elder, the manager of Mr. Napier’s works, and is one of the largest yet made, being intended principally 
 for use in the building yard, where plates of greater thickness come under operation than those required 
 in boiler-making. 
 
 Fig. 3098 is a side elevation of the machine, and Fig. 3099 an end view towards the driving-geer. 
 
 Fig. 3100 is a plan corresponding to Fig. 3098. 
 
 General description . — The frame of the machine consists of two very strong end standards A A, cast 
 with soles to admit of their being bolted down to a solid stone foundation. They are braced together 
 by four strong rods of malleable-iron a a a, the screwed ends of which pass through projections on the 
 standards, of such thickness that the nuts by which they are secured are nearly flush with the outside 
 of the frames, thus obviating the necessity for having the geering far overhung. 
 
 The three rollers BCD are solid ; the dimensions of each being 12 inches diameter, and 10 feet long 
 within their bearings. The two rollers B and C are placed in the same vertical plane; but the third 
 roller D moves in a plane inclined at an angle of thirty degrees to the vertical plane. On one end ot 
 the roller B is keyed a strong pinion E, which geers with another pinion of the same size marked G on 
 the end of the lower roller C. On the opposite end of this last is fixed a large spur-wheel H into which 
 works a pinion I on the shaft J, which has a bearing in each of the two standards, and carries on its 
 other end a large spur-wheel K, commanded by a pinion upon the driving-shaft L. One end of this 
 shaft is carried in a bearing in the adjacent standard of the machine, and the other in an independent 
 standard M bolted to the foundation. It carries four pulleys, two of which, N O, are fast upou the shaft, 
 and the other two, P Q, of double the breadth of the former, are loose. On these are two belts, the one 
 cross and the other open, so that the rollers may be driven in either direction according as the motion 
 is communicated by the open or the cross belt. The belts are shifted on their pulleys by means of the 
 hand-bar R, on which are the guide-arms S T, so placed that in reversing the motion of the machine, 
 the belt thrown out of action shall have passed entirely from its fast pulley before the other shall have 
 passed from its loose pulley to the fast one. This arrangement obviates the injurious effect so common 
 in machines furnished with this species of driving-geer, of the one belt acting against the other during a 
 part of the time of shifting, thereby occasioning much unnecessary tear and wear of the belts. 
 
 The upper roller B is adjusted to the thickness of the plate to be bent by two strong set-screws U IT, 
 which work in hexagonal brass nuts inserted into recesses in the standards. These screws bear againel 
 
PLATE-BENDING MACHINE. 
 
 509 
 
 a steel plate resting upon the brass block in "which the roller revolves, and which is of course placed 
 over the journal, the pressure being upwards ; and thus the roller is kept pressed down upon the plate, 
 as it passes through the machine in the operation of bending. 
 
 The roller D is adjusted to the required position by the double hand-crank on the upper end of the 
 vertical spindle b b, which communicates by means of a pair of small bevel-wheels c c with the screws 
 dd, working into long brass nuts ee inserted in recesses of the frame. The upper ends of these nuts 
 support the bearings of the roller, which may consequently be raised and lowered at pleasure, according 
 as the spindle is turned in one direction or the other. The nuts ee are prevented from turning round 
 with the screws by feathers upon the back of the brasses fitting into grooves on the ends of the nuts 
 
 In machines of this kind it is common to provide geering for working both ends of the shifting-roller 
 simultaneously, so that the rollers may always preserve their parallelism. But in the present example 
 that mechanism has been purposely omitted, to adapt it for bending the same plates with different de- 
 grees ot curvature at the opposite edges ; a description of work much required in the building yard and 
 Tther CaD ° Dly be effected by “S one end of tlle mov able roller D proportionally higher than the 
 
 Action of the machine . — From this outline of the arrangement, the action of the machine will be 
 easily understood. Motion being communicated through one of the belts to the driving-shaft L, the 
 pinion upon the end of that shaft geering with the large wheel K gives motion to the shaft J ; this mo- 
 tion by means of the pinion I, is transferred to the large wheel H, which is fast on the under roller C 
 
510 
 
 PNEUMATICS. 
 
 This roller being put in motion, communicates an equal velocity to the upper roller B by means of the 
 pinions E and G which geer together. The roller L>, the position of which determines the degree ot 
 curvature ot the plate under operation, is only driven by the friction of the plate against it as it passes 
 between the two other rollers. 
 
 Literal references. 
 
 3099. 
 
 A A, the end standards of the machine. 
 
 a a a, stay-rods, 2 inches diameter, for connecting 
 the two standards. 
 
 B, the upper roller, 12 inches in diameter, and 10 
 feet long between its bearings, which are 51- 
 inches in diameter. 
 
 C, the lower roller, of the same dimensions. 
 
 D, the shifting-roller, of the same dimensions. 
 
 b, the upright spindle for setting the roller D. 
 
 c, small bevel pair worked by the spindle b. 
 
 il, a screw, 2§ inches diameter, and § inch pitch. 
 
 e, brass nut into which the screw d works. 
 
 E, a pinion on the end of the top roller B ; pitch 2i 
 niches, number of teeth 1 G. 
 
 G, a similar pinion on the lower roller C. 
 
 H, a large spur-wheel on the opposite end of the 
 roller C; pitch 1J inch, number of teeth 100. 
 
 I, a pinion of 13 teeth, working into the spur- 
 wheel H. 
 
 J, a wrouglit-iron shaft conveying motion to the 
 pinion I from 
 
 K, a spur-wheel at the opposite end of the ma- 
 chine ; pitch 11 inch, number of teeth 75. 
 
 L, the driving-shaft of the machine. 
 
 M, a standard for supporting the exterior end of 
 the driving-shaft. 
 
 N O P Q, fast and loose pulleys for setting in mo- 
 tion, stopping, and reversing the machine. 
 
 R, the hand-bar for shifting the belts. 
 
 S T, guide-arms fixed on the hand-bar R. 
 
 U U, screws for adjusting the top roller. 
 
 PLATINUM. (So called from the Spanish word plata, silver, on account of its color.) A metal of » 
 white color, exceedingly ductile, malleable, and difficult of fusion. It is the heaviest substance known, 
 its specific gravity being 21'5. It undergoes no change from air or moisture, and is not attacked by any 
 of the pure acids ; it is dissolved by chlorine and nitromuriatic acid, and is oxidized at high tempera- 
 tures by pure potossa and lithia. It is only found in South America and in the Uralian Mountains : it 
 is usually in small grains of a metallic lustre, associated or combined with palladium, rhodium, iridium, 
 and osmium ; and with copper, iron, lead, titanium, chromium, gold, and silver ; it is also usually mixed 
 with alluvial sand. The particles are seldom so large as a small pea, but sometimes lumps have been 
 found of the size of a hazel-nut to that of a pigeon’s egg. In 1826 it was first discovered in a vein associated 
 with gold, by Boussingault, in the province of Antioquia, in South America. When a perfectly clean surface 
 of platinum is presented to a mixture of hydrogen and oxvgen gas, it has the extraordinary property of 
 causing them to combine so as to form water, and often with such rapidity as to render the metal red- 
 hot : spongy platinum, as it is usually called, obtained by heating the ammonio-muriate of platinum, is 
 most effective in producing this extraordinary result ; and a jet of hydrogen directed upon it may be 
 inflamed by the metal thus ignited, a property which has been applied to the construction of convenient 
 instruments for procuring a light. The equivalent of platinum is about 98. It is precipitated from its 
 nitromuriatic solution by sal ammoniac, which throws it down in the form of a yellow powder, composed 
 of bichloride of platinum and sal ammoniac. 
 
 PNEUMATICS. The science which treats of the mechanical properties of elastic fluids, and particu- 
 larly of atmospheric air. 
 
 Elastic fluids are divided into two classes — permanent gases and vapors. The gases cannot be con- 
 verted into the liquid state by any known process of art ; whereas the vapors are readily reduced to 
 the liquid form by pressure, or diminution of temperature. In respect of their mechanical properties 
 there is, however, no essential difference between the two classes. 
 
 Elastic fluids, in a state of equilibrium, are subject to the action of two forces ; namely, gravity, and 
 a molecular force acting from particle to particle. Gravity acts on the gases in the same manner as on 
 all other material substances ; but the action of the molecular forces is altogether different from that 
 which takes place among the elementary particles of solids and liquids ; for, in the case of solid bodies, 
 the molecules strongly attract each other, (whence results their cohesion,) and, in the case of liquids, 
 exert a feeble or evanescent attraction, so as to be indifferent to internal motion ; but, in the case of the 
 gases, the molecular forces are repulsive, and the molecules, yielding to the action of these forces, tend 
 incessantly to recede from each other, and, in fact, do recede, until their further separation is prevented 
 by an exterior obstacle. Thus, air confined within a close vessel exerts a constant pressure against the 
 interior surface, which is not sensible, only because it is balanced by the equal pressure of the atmos- 
 phere on the exterior surface. This pressure exerted by the air against the sides of a vessel within 
 which it is confined is called its elasticity, or elastic force, or tension. 
 
 Conditions of equilibrium. — In order that all the parts of an elastic fluid may be in equilibrium, one 
 condition only is necessary ; namely, that the elastic force be the same at every point situated in the 
 same horizontal plane. This condition is likewise necessary to the equilibrium of liquids, and the same 
 
PNEUMATICS. 
 
 511 
 
 circumstances give rise to it in both cases ; namely, the mobility of the particles, and the action of gravity 
 upon them. Conceive a close vessel to be filled with air, or a gas ; and let a and b be two molecules 
 situated in the same horizontal plane. It is evident that if the two molecules are in a state of equili- 
 brium, the force with which a repels b must be exactly counteracted by that with which b repels a, for 
 otherwise motion w y ould take place. The same thing takes place in respect of every horizontal section 
 of the gas ; but the pressure on each section varies with its altitude. Suppose c and d to be tw r o mole- 
 cules situated in a horizontal section, lower than that in which are a and b. It is evident that the mole- 
 cules c and d sustain a greater pressure than a and 6; for, in -the first place, the whole of the pressure 
 on a and b is transmitted to them by the principle of the equality of pressure in all directions ; and, in 
 the second place, they sustain a new pressure, arising from the weight or gravity of all the molecules 
 situated between the two horizontal planes a b and c d. 
 
 The principle which has just been explained is proved experimentally by the diminution of the pres- 
 sure of the atmosphere at greater altitudes. A column of air reaching from the ground to the top of 
 the atmosphere exerts a pressure equal to the weight of a colunrn of mercury of the same diameter, and 
 whose height is equal to that in the barometric tube. Now, on carrying the barometer to the top of a 
 mountain, for example, the mercurial column is observed gradually to become shorter as we ascend ; 
 and the diminution of the column, and consequently of atmospheric pressure, is connected with the in- 
 crease of altitude by a certain constant law, which enables us to deduce the one from the other, and to 
 apply the barometer to the very important purpose of determining the relative altitudes of places on 
 the surface of the earth. 
 
 The volumes of gases are inversely as the pressures which they support. — This fundamental property 
 of elastic fluids is called the Law of Mariotte , from its having been discovered by that philosopher in 
 France. It has been verified in several ways, on all the known gases ; and, in the case of dry air, its 
 verification has been pushed, by MM. Dulong and Arago, to pressures equivalent to twenty-seven at- 
 mospheres. (Lame Gours de Physique.) It also holds true in respect of vapors or steam, subjected to 
 a smaller degree of pressure than that which is necessary to reduce them to the liquid state ; and even 
 for mixtures of different gases. It is important, however, to observe, that it is supposed no variation 
 of temperature has taken place during the experiment. 
 
 The density of bodies being inversely as their volumes, the law of Mariotte may be otherwise ex- 
 pressed, by saying, the density of an elastic fluid is directly proportional to the pressure it sustains. 
 Under the pressure of a single atmosphere, the density of air is about the 770th part of that of water; 
 whence it follows that, under the pressure of 770 atmospheres, air is as dense as water. Thus, the 
 average atmospheric pressure being equal to that of a column of water of about 32 feet in altitude, at 
 the bottom of the sea, at a depth of 24640 ( = 770 X 32) feet, or 4f miles, air would be heavier than 
 water ; and though it should still remain in a gaseous state, it would be incapable of rising to the surface. 
 
 Effects of heat on the elasticity of the gases. — The repulsive energy of the molecules of the elastic 
 fluids is greatly augmented by an increase of temperature ; and it is of the utmost importance in many 
 physical inquiries to ascertain the relation between the temperature and the elastic force. If the air 
 and several other gases, sustaining the same constant pressure, are exposed to an increase of tempera- 
 ture which affects all of them equally, it is proved, by observation, that they all undergo an equal ex- 
 pansion ; that is to say, the increase of volume of all the gases is the same for equal augmentations of 
 temperature, and proportional to these augmentations. Experience also shows that, within a considera- 
 ble range of temperature, the indications of the air thermometer differ very little from those of the mer- 
 curial thermometer ; so that, within this range, the expansion of any gas whatever is proportional to the 
 increase of temperature indicated by the degrees of the ordinary thermometer. From the temperature 
 of melting ice to that of boiling water, or from zero to 100° of the centigrade thermometer, Gay-Lussac 
 found the expansion of air subjected to a constant pressure, to be in the ratio of unity to 1'375 ; which 
 gives an expansion of 000375 for each centigrade degree. This being assumed, let Y be the volume 
 of any gas at the zero temperature, P its elastic force, or the pressure it sustains, and D its density. 
 Let a = '00375, and suppose the values of V and D to become V' and D' when the temperature is in- 
 ti eased t degrees; then the pressure P being supposed constant, we have evidently 
 
 V' = V(1 +<zf ); 
 
 and the density being inversely as the volume, we have, also, 
 
 D'= ° 
 
 1 -j- a t 
 
 Now, suppose the pressure to be varied without any change of the temperature, and let y> denote the 
 Dew pressure, and d the corresponding density; the law of Mariotte gives 
 
 p d 
 
 P : D 1 ::p: d, whence p = — ; 
 
 p 
 
 and, on substituting for D' its value given by the preceding formula, and making — = k, we obtain 
 . p = kd{ 1 + at) 
 
 for the expression of the elastic force of any gas in a function of its density and temperature. 
 
 The coefficient k is constant for the same gas, but has a different value for different gases, depending 
 on their densities or specific gravities. With respect to atmospheric ah', its value may be found thus : 
 The density of air, compared with water, is 0'0013, and that of mercury 13'59 ; therefore, supposing the 
 height of the barometer to be 30 inches, the value of k, or the height of a column of air of uniform den- 
 
 sffy, exerting on its base a pressure equal to that of the atmosphere, is 30 in. X — = 313860 inches 
 
 ar 26155 feet, (about five miles,) the temperature being that of freez-water 
 
512 
 
 POLARIZATION OF LIGHT. 
 
 Of the motion of the gases. — Elastic fluids, in escaping from a vessel by a small orifice or tube, into a 
 vacuum, observe, like liquids, a law first discovered by Torricelli ; namely, that the velocity of the mole 
 cules, when they escape from the orifice, is equal to that which they would have acquired by falling 
 through a height equal to the height of a vertical column of uniform density, producing the same pres- 
 sure as is exerted by the gas at the level of the orifice. Thus, it has just been shown that the pressure 
 of the atmosphere, when the barometer stands at 30 inches, and the temperature is that of freezing, is 
 equal to that which would be produced by a column of air of uniform density extending to an altitude 
 of 26155 feet. Now, putting g = the accelerating force of gravity = 32 feet per second, the velocity 
 which a heavy body would acquire by falling in a vacuum from a height of 26155 feet, is ^/(2 g X 
 26155) = 8^/26155 = 1294 feet in a second; which, therefore, is the velocity with which air rushes 
 into a vacuum. If the temperature varies, the velocity will vary also, and will become 1294 -J (1 -+- a t). 
 For example, if the temperature were 16° centigrade, (about 61° of Fahrenheit,) the velocity would be 
 1332 feet per second. 
 
 Since the densities of the gases are proportional to the pressures they support, air will always rush 
 into a vacuum with the same velocity, whatever its density may be in the vessel from which it escapes ; 
 for the homogeneous column of the same density, and exercising the same pressure as the air in the 
 vessel, must, in all cases, have the same altitude. 
 
 The velocities with which the different gases enter a vacuum are inversely as the square roots of their 
 densities ; for they are proportional to the square roots of the altitudes from which the molecules are 
 supposed to fall, and these altitudes are inversely as the densities. Thus, hydrogen gas, the lightest of 
 all the gases, and whose density is only 00688 of that of air, would enter a vacuum with a velocity of 
 4933 (=1294 divided by the square root of 0-0688) feet in a second. It is to be remarked, however, 
 that all those laws relative to the flow of gases, are rather inferences from theory than truths demon- 
 strated by direct experiment. 
 
 In the case of air or any gas flowing into a space containing a gas of an inferior density, the velocity 
 will be the same as that of an incompressible liquid of similar density with the effluent gas, and capable 
 of exercising a pressure equal to the difference between the pressures of the two gases. Taking, for 
 example, the case of a gas flowing from a gasometer into the atmosphere : let h denote the height of 
 the barometer, and h + II that of the column of mercury exercising a pressure equal to the elasticity 
 of the effluent gas, so that 11 is the difference of the two pressures. Also, let A denote the density of 
 mercury, d that of the gas in the gasometer corresponding to the pressure h -f- H, and v the velocity per 
 second ; then 
 
 Now if, in the formula p — hd(\ -f- at ), we substitute the pressure in the gasometer (A -f- H) A for 
 p, and also for k its value as above determined in feet, this expression will become, 
 
 w 1 294 ,/ j (1 + a () | , 
 
 where v is expressed in feet. If, therefore, A denote the area of the orifice in feet, the volume or num- 
 ber of cubic feet discharged in a second will be v A. It is to be observed, that the volume thus deter- 
 mined is the volume of a gas of the same density as in the gasometer ; if it were required to find the 
 number of cubic feet, at a different density, corresponding to the pressure of a mercurial column whose 
 height = h\ it would be necessary to multiply the above expression by the ratio (h -}- H) —■ h'. 
 
 From the experiments of D’Aubuisson, it has been ascertained that air, in passing through an orifice 
 pierced in a thin plate, forms a vena contracta, whose area, as in the case of a liquid, is 065 of the area 
 of the orifice. The application of cylindric adjutages increases the quantity issuing through the orifice 
 to 0'93, and a conical tube to 0'95. The length of the adjutage may be 20 or 30 times the diameter of 
 the orifice before the discharge begins to be diminished by friction. If, therefore, we suppose the gas 
 to flow through a cylindric tube, and assume the multiplier 0’93 ; and also express the area of the orifice 
 in terms of the diameter of the tube, which we shall suppose = in feet ; then, observing that 4 A = 
 3T4159w 2 , the formula for the number of cubic feet discharged in a second, the density being measured 
 by h -f H, will become 
 
 945 wV lrFH ( 1 +a<) S- 
 
 POLARIZATION OF LIGHT. Light which has undergone certain reflections or refractions, or 
 been subjected to the action of material bodies in any one of a great number of ways, acquires a certain 
 modification, in consequence of which it no longer presents the same phenomena of reflection and trans- 
 mission as light which has not been subjected to such action. This modification is termed the polari- 
 zation of light ; its rays being supposed, according to particular theoretical views, to have acquired 
 poles (like the magnet) or sides with opposite properties. 
 
 The polarization of light may be effected in various ways, but chiefly in the following : 1. By reflec- 
 tion at a proper angle from the surfaces of transparent media, as glass, water, &c. 2. By transmission 
 
 through crystals possessing the property of double refraction. 3. By transmission tlirough a sufficient 
 number of transparent uncrystallized plates placed at proper angles. 4. By transmission through a 
 number of other bodies imperfectly crystallized, as agate, mother of pearl, itc. The saccharometer 
 lately invented is based upon this property of light, 
 
 POTASSIUM. This extraordinary metal was discovered by Davy, in the year 180Y, and was one of 
 the first fruits of his researches into the chemical powers of electricity. Its properties are so remark 
 able, that it was for a time doubted whether it could with propriety be placed among the metals ; but 
 •he progress of discovery has removed all difficulty upon that point, by making us acquainted with 
 
PRESS, PROGRESSIVE-LEVER STEAM. 
 
 513 
 
 other metallic substances, the properties of which are, as it were, intermediate between those of potas- 
 sium on the one hand, and the common metals on the other. One of the striking peculiarities of 
 potassium is mechanical rather than chemical, namely, its low specific gravity, it being the lightest 
 known solid ; another is its intense affinity for oxygen, and its consequent energetic action when placed 
 upon water, where it immediately takes fire. The specific gravity of potassium is - 865 at the tem- 
 perature of 60° ; it is solid at the ordinary temperature of the atmosphere; at 80° it becomes soft, and 
 at 150° is perfectly liquid; at 32° it is brittle, and has a crystalline texture. In color and lustre it 
 resembles mercury. Its attraction for oxygen is such that it immediately loses its brilliancy on ex 
 posure to air, and becomes converted into potassa. 
 
 PRESS. Under the head of hydrostatic press will be found a full description of Bramah's most 
 useful invention, and this is in general use for the billing of goods for shipment, for the pressing of paper 
 among printers and lithographers, for the corrugation of iron and metals. It was used by Stephenson 
 for raising the tubes of the Conway and Menai Bridges, and by Brunei for the launching of the Levia- 
 than. It is the most compact of all machines for the transfer and multiplication of power, but is slow 
 in its operation, as usually the speed when driven by power is the same with and without the maximum 
 lead. 
 
 To obviate this difficulty, a steam press has been invented by Philos B. Tyler, called the Progres- 
 sive Lever Steam, lGth January, 1845, which is extensively used in the baling of cotton. 
 
 3099. 3100. 
 
 Looking to the fact that at the commencement of the operation the resistance is very small, scarcely 
 perceptible, and gradually increases as the density of the cotton increases under the action of the press. 
 Mr. Tyler conceived the happy thought of interposing between the piston-rod of the engine and the fol- 
 lower of the press, what are known in mechanics as progressive levers ; that is, levers so arranged that 
 at the commencement of the operation, when the resistance presented by the cotton is at its minimum, 
 the arms in connection with the follower shall be at their greatest length, and those in connection with 
 the piston at their shortest, and, as the resistance increases, that these relations of the arms of the levers 
 shall be changed gradually and in proportion to the increasing resistance of the cotton, until at the end 
 of the operation — when the cotton presents its maximum resistance — the arms of the levers in connec- 
 tion with the piston shall be at their greatest length, and those in connection with the follower at their 
 Bh ortest. 
 
 By this combination, mechanically true and admirably adapted to the purpose, Mr. Tyler was enaoled 
 to produce a steam-press which will compress a bale of cotton within the smallest practicable compass 
 with a steam-cylinder and piston of very small capacity, and economize to the utmost the consumption 
 of steam ; for at no time from the commencement to the end of the operation, is there any more steam 
 applied and consumed than what is necessary to meet and overcome the resistance presented by the 
 cotton and the necessary friction of the mechanism. 
 
 Vol. II.— 33 
 
514 
 
 PRESS, ANTI-FRICTION CAM. 
 
 There are various modes of applying the principle of this invention, for there are various modifica- 
 tions of the progressive lever, all of which may he employed to form the connection between the piston 
 and the follower of the press, on the principle invented by Mr. Tyler ; but the arrangement selected and 
 adopted by bin) is represented in the accompanying engravings, in which Fig. 3009 is a front, and Fig. 
 3040 a side elevation. 
 
 In this arrangement the bed a is inverted and attached to the under side of a beam b of the frame, 
 •o the upper side of which beam is secured the cylinder c, of the steam-engine, to avoid undue strain on 
 the frame ; for in this way the beam is simply exposed to a crushing force. 
 
 Within the cylinder there is a piston of the usual construction, the rod d of which is provided on ojv- 
 posite sides with cogs e e, to form two racks which engage the cogs of two sector-racks ff that turn on 
 fulcrum-pins g g. As the fulcrum-pins of these two sectors have to bear the brunt of the power applied, 
 the boxes in which they turn are secured at the angles formed by a cross-beam h, and the sides ii of 
 the frame, and from the under side of this cross-beam, there are two diagonal braces which extend down 
 to, and rest on the beam b, each side of the steam-cylinder. 
 
 The sectors are connected with the follower R of the press by means of four connecting-rods III l, 
 two on each side. 
 
 The steam-cylinder is provided with the requisite steam and discharge pipes and valves, by means 
 of which the attendant admits steam from a boiler to the under side of the piston, and, at the end of 
 the operation, permits it to escape. 
 
 From the foregoing it will be seen that when steam is admitted the piston is forced up, which causes 
 the two sectors to vibrate, and by reason of their connections to draw up the follower, forcibly com- 
 pressing the cotton between its upper surface and the under surface of the bed until the cotton is com- 
 pressed into a bale m , of the required density, which is then tied up in the usual way. 
 
 It will be observed that the line of action of the piston-rod on the two sectors is always at the same 
 distance from their fulcra, so that these two will be constant levers during the entire operation, but the 
 connecting-rods attached to the follower being jointed to the sectors, as these vibrate upwards, the lines 
 of the rods gradually approach the fulcra ; hence the leverage of these connections gradually decreases 
 during the operation ; and from this it follows that the leverage power with which the piston acts on 
 the follower, gradually increases in the ratio of the increasing resistance of the cotton. 
 
 This is a good form of press, both from the soundness of the principle on which it rests, and the sim- 
 plicity of the mechanical arrangement employed to carry out that principle. In practice it is found 
 to economize fuel and labor, and is so easily managed by ordinary hands that it will supersede many 
 other presses for this purpose. 
 
 A press similar in principle to this, but worked by hand instead of power, is used in many of the 
 smaller cotton factories for the baleing of goods. 
 
 PRESS. Dick’s Anti- Friction Cam. For punching and shearing iron and metals, a new principle 
 of press has been introduced by Mr. Dick of Meadville, Pennsylvania, called the anti-friction cam: the 
 machines are extensively made at Holyoke, Massachusetts. The principle of their construction will 
 he readily understood from the following cuts and description : 
 
 Fig. 3103 represents the elevation, Fig. 3103 a section, and Fig. 3104 the combination of cams on a 
 larger scale of one form of these presses intended for a punch. A A are two eccentric wheels ; B is a 
 roller between ; c c are two pairs of sectors, constituting the hearings of the axes of the eccentric 
 
 310 .!. 3103 . 
 
PRESS, ANTI-FRICTION CAM. 
 
 515 
 
 wheels ; D D are sections of the follower and bearing of the sectors. The axes of the sectors are angu- 
 lar or edge shaped. 
 
 The centre roller B is made to revolve by means of the winch or lever E, which carries by its tractive 
 qualities the two eccentric wheels A A, the axes of which having their bearing on the face of the sectors, 
 
 3104. 3105. 3106. 
 
 are transferred the length of their faces right and left ; and as the sectors are edge shaped at their centre 
 of motion o o, they necessarily revolve free from the impediment of rubbing surfaces, and consequently 
 without friction. 
 
 When the eccentric wheels have made their revolution, the follower will have moved the sum of two 
 eccentrics. When the press is constructed so that the follower movis down, a spring G may be used to 
 return the moving parts to their places when the press is relaxed. 
 
 requiring but little movement or traverse of the follower. 
 
 A A, Fig. 3104, are two eccentric sectors ; B is a centre roller ; C C are sections of the follower and 
 Bearing. Fig. 3106 is an edge view of the same, showing the longitudinal extension of the edges con- 
 
516 
 
 FEINTING MACHINE. 
 
 stituting the axes of the sectors. Fig. 3107 is a view of the same as it is set in the frame, with one side 
 of the frame removed. Fig. 3108 is an edge view of the same with frame and lever all complete. 
 
 For further illustration of mechanical devices which maybe ranked among presses, see Embossing 
 Machine, Punching and Shearing Machine, Printing Press, etc., etc. 
 
 PRINTING MACHINE, S. W. Francis’ Patent. The principal feature of this invention consists ir. 
 arranging a row of hammers in a circle, so that, when put in motion, they will all strike the same place, 
 which is the centre of the said circle. The paper is not touched by the operator till the page is finished, 
 being worked by means of a spring and catch, so connected with the keys, that it moves the pa- 
 per the distance of one letter whenever a key is struck. On the face of each hammer a letter is cut in 
 relief, in such a position, that its impression on the paper is parallel with those of the others. When 
 within four letters of the end of the line, a little hell rings, giving notice to the operator that the word, 
 if of more, than one syllable, must he divided by a hyphen. At the end of each line, the “car,” which 
 carries the paper, is drawn back, and the paper is moved the distance of two lines, in a direction perpen- 
 dicular to the printed line, by means of a catch hereinafter described. The keys are connected with 
 actions somewhat similar to those used in pianos, by means of wires and hell-cranks, which actuate the 
 hammers. There is also an arrangement for rendering the simultaneous action of two or more hammers 
 impossible. It is obvious that by causing two or more hammers to strike against each other, serious in- 
 ; ury would be caused — rendering machines, where key-boards are used, practically useless. 
 
 Fig. 3109 represents a top or plan view of the machine (in part); fig. 3110 a detailed section of an 
 action and hammer, and fig. 3111 an open and front view of the stop-bolts beneath the keys, for the 
 purpose of preventing the downward motion of more than one at the same time. 
 
 (Fig. 3109). B is one of the sides, which together with the cross-bars F and C, fig. 3110, forms part of 
 the frame to which all parts of the mechanism are secured. Fig. 3110. The keys K L , K 1 L, are disposed 
 in a longitudinal series under the cross-bar C. They all carry a counter weight M, which brings them by 
 gravity to rest against the board A. Their downward motion is checked by a cross-bar into which the 
 screw R enters — two pi?.s act as guides for each key. Under and between the keys, (fig. 3111,) a row of 
 vertical stop-bolts P Q, P Q',P" Q”, are pivoted by screws^, It', It", and are in contact with each other; 
 the tops are bevelled on both sides, and are lodged in corresponding recesses of and between the keys. The 
 recesses are made twice as large as the tops of the stop-bolts PQ, P' Q', which enter them. By this 
 arrangement it is impossible to bring down more than one key at the same time ; for supposing a key K', 
 depressed, the stop-bolt P Q, placed on the left side of the key, with all the other stop-bolts on the same 
 slide is pushed simultaneously in the same direction. The same effect is produced on the right side Tie- 
 ginning with stop-bolt P' Q', and so on. If, however, it is attempted to bring down two keys at once, all 
 the stop-bolts between them, being equally pressed to the left and right, will keep their places directly 
 under the spaces between the keys, whereby the two keys which are acted upon, are prevented from 
 coming more than A of an inch. 
 
 (Fig. 3109.) The keys are connected with the “ actions ” by means of wires V, V, V, S, S', S’, and 
 bell cranks T, T', T". These actions and the hammers are attached to a circular frame F, (in fig. 3110,) 
 which is fastened to central opening of the board A, (fig. 3110). Each action is composed of a rocker p 
 movable on a fulcrum, of a pawl p, having its fulcrum attached to the upper end of the hammer at Z. 
 When a key K , is depressed, that part of it to which the wire S is attached at o", pulls upon the rocker 
 p , moving the pawl p, and thereby causing the hammer V to strike the stud PI. 
 
 (Fig. 3109). An arm h projects, from which hangs a stud, fig. 3110, against the end of which all the 
 hammers are made to strike. This arm moves on a cam, and is turned up on either side, while the 
 paper is put in the car g' d' e' , which moves on rails c, V . 
 
 The inking is effected by a silk band p, which is carried on four pulleys similar to l, secured .on two 
 sliding brackets similar to z v. The brackets may be elevated when the band is inked — it retaining ink 
 for four days. The paper is carried upon a “ car,” sliding between two rails c b ' ; this car consists of a 
 quadrangular frame d' e' f g' , supporting two rollers h i', and the heavy flat bar J', to which the latter is 
 united by means of levers p q , n' n', and rod m' , in such a manner, that when J’ is raised from the 
 frame, along a circle the centre of which is at n' , the roller i' is equally raised by moving round the 
 axis p q . The paper to be printed is first placed upon the roller h 1 , the roller I is then brought down 
 upon it, and the weight of the bar J' causes the rollers to hold together. 
 
 The car is propelled by a spring power, which consists of a spiral spring pulling the car by means of 
 string s' passing over pulleys in a direction contrary to the lines to be printed. To the opposite end of 
 the car is atfached a cord a', which, passing over a pulley, winds around a barrel b " ; the latter is firmly 
 mounted upon a round disc c" , which is furnished with a row of pins near the periphery thereof, d is a 
 catch ; on the under side it has a notch, through which the pins may pass in one direction only ; this is 
 effected by means of a spring which causes the opening by the pressure of the pins against it, thus es- 
 tablishing a bar against the passage of the said pins ; hence, against the revolution of the disc in that 
 direction. The catch is connected by a proper system of leverage with the frame g h and the. side of 
 the caseing. The frame bears against a stud by means of a spring, but when acted upon by either of 
 the levers L, (fig. 3110,) it will also actuate the catch by withdrawing the spring from the said pressure 
 of the pins. The spring thus relaxed allows the passage of one pin, but backs against the next following 
 one. These are the means employed to feed the “ car,” and consequently the paper, the distance of one 
 single letter, until the whole line is completed. 
 
 The knob q", is then pulled so as to bring the stud PL, (fig. 3110,) to bear against the first letter of 
 the next following line. The moving of the paper in a direction perpendicular to the lines is effected by 
 means of a spider-wheel v", made fast to the shaft end of the roller I, and by means of a lever S", and 
 spring it. When the car is pulled to the right, one of the spokes of the spider-wheel v" is pressed against 
 the inclined side of the lever S", and is turned the distance of two lines ; but when the car goes back, the 
 spring u plays and the position of the spider-wheel v" remains unchanged. Tht> pulley similar to l ia 
 
FEINTING MACHINE, 
 
 517 
 
518 
 
 PRESS, LITHOGRAPHIC PRINTING. 
 
 free on the shaft of the band pulley, and carries a ratchet so arranged in relation to a ratchet wheel up* 
 on the shaft, that when the car is moved to the right the pulley turns freely, and when the car moves te 
 the left, the pulley carries the other pulley with it ; the band is thus caused to follow the movements of 
 the car, and every letter strikes it in a different place. The band is placed between two pieces of paper, 
 a thick one below and a thin one above ; by this means two copies are printed at the same time and 
 with equal facility. 
 
 The above description with the cuts, explains fully the construction of a machine necessarily some- 
 what complicated, but not necessarily liable to derangement by use. On examining the above cut or 
 perspective view of the complete machine, it will be seen to resemble a piano in its general form and 
 arrangements, in its finger-board, and in the position of the manuscript or rather proof. The keys re- 
 spond as easily to the touch, and the letters appear on the paper in front of the operator. The average 
 size of this portable machine is two feet square, not much larger than a writing desk. 
 
 FRINTING-PRESS, LITHOGRAPHIC. Fig. 3109 is a front elevation of a lithographic printing press, 
 by William Smart, of London. The principle of it consists in the whole of the press-work, with the ex- 
 
 ception of the operation of laying on and taking off the paper, being performed by a series of movements 
 resulting from the first motion given to the machine, and not requiring the aid of hand labor to perform 
 the work as heretofore. A portion of the standard frame is removed at one end. A A are the stand- 
 ard and body frames of the machine. B E is the driving-shaft and pinion, receiving motion from steam 
 or any motive agent, and communicating the same to the wheel C, which takes into and geers with D, 
 thereby giving motion to the wheel G, which drives the pinion F. Keyed on the main shaft with the 
 
PRINTING PRESS. 
 
 519 
 
 pinion F is a large toothed wheel H, moving loosely on its centre or shaft, the periphery of which i? 
 perforated with the stud holes at the side, of sufficient size to enable the studs, when brought in con- 
 tact witli them, to enter into and take hold of the wheel H ; for this purpose a ring or disk of metal 
 keyed to the main shaft with the projecting studs is employed, so that by any lateral action, caused bv 
 a shifting clutch-box on the main shaft, the wheel II may be coupled witli the fixed disk by the studs 
 entering into and uniting the two together, and revolve with the main shaft ; mounted, also, upon this 
 shaft, there is a concentric double-action motion rack I, in which a pinion takes into, first on the outside 
 thereof, thereby causing the toothed wheel II to be thrown in play during the printing process in one 
 direction ; and secondly, on the inside, by passing through an opening in the periphery of the rack, and 
 reversing the wheel. J is a horizontal rack, moving longitudinally in the direction of a machine, in a 
 suitable iron bed, in geer with the large toothed wheel H. K is a wooden bed or sleeper fixed to the 
 traversing-frame, on which a rectangular slab of slate is fitted to receive the stone L at the top. M are 
 surplus head standards carrying the wetting and inking apparatus ; this part of the improvement con- 
 sists in giving motion by means of the endless strap from the driving rigger on the main shaft to the 
 doctor ink-roller, which revolves at right angles with the supply and distributing rollers situated under- 
 neath, in the manner represented by the figures 1, 2, 3, 4, 5, 6, *7, 8, 9 ; for example, by the revolution* 
 of the rollers 2 3 moving on the face of the doctor they receive ink therefrom and convey it, through the 
 intervention of other rollers, to the stone, thereby completing the process of inking in the manner de- 
 scribed. N is the water-trough and sponge-box. It consists of a vessel of water having a series of 
 tubes passing through the bottom of the box with their upper ends above the surface of the water, 
 whilst their lower ends communicate with the sponge. A warp of cotton is placed in the upper ends of 
 the tubes, and allowed to descend into the trough below the water, which causes, by capillary att-rs - 
 tion, the water contained in the trough to pass down the tubes in connection with the sponge, and 
 supply it with water without overcharging it. This box is brought down on the surface of the stone 
 when passing under for the purpose of wetting, and remains until the subsequent process of inking is per- 
 formed, when, upon the stone returning to the centre of the machine from which it started, to receive the 
 paper, the action of a cam, so operating upon a vertical rod in connection with it, causes the box to be 
 raised and the stone to pass out in readiness for the next operation. O is a small framing mounted on 
 the body standards A, for carrying the scraper and tympan-roller P. Q is the scraper, fixed to a strong 
 cross-head, which is regulated to any height by the screw R in the centre. S is the tympan-cloth, 
 which is fixed at one end to a bar T ; the other end is coiled round a roller P, on the shaft of which a 
 pulley-wheel is fixed, having a cord or rope bearing on it in such a manner that by the effect of this 
 rope passing over another pulley, suspended at a distance apart, as shown, it shall cause, by the action 
 of a weight at one end, the tympan-cloth to be kept stretched, so that when the traversing-frame, witi; 
 the stone, is passing under the scraper, it may catch hold of the bar T, and by the onward motion of the 
 traversing-frame unwind the tympan-cloth and lay it over the stone until it shall have passed under 
 the scraper and completed the printing operation. When, by the pressure being withdrawn from un- 
 derneath the stone, the weight suspended from the end of the cord in connection with the pulley P is 
 then the medium through which the bed and stone is driven back into the centre of the machine ready 
 for the next operation, by reason of the weight acting in such a manner that when the tympan-cloth 
 has been unwound and placed on the surface of the stone, the mode of again winding it up is only 
 effected by the proximity of the bar T to the roller P producing the diminution in the space from the 
 contraction of the tympan-cloth. To apply the power to the scraper and the traversing-frame, a pressui e 
 roller is employed, actuated by a cam producing pressure at given times, such as when the stone is 
 passing under the scraper ; but as soon as it has performed such operation the pressure will be with- 
 drawn, and the means employed to assist its return rendered free to act. There is an arrangement, 
 consisting of a long bar or bearer U, with a counterbalance weight affixed; this bar passes along (he 
 sides of the frame-work, and touches the boss of the cam-wheel V, to which is attached a concentric 
 arm revolving with it ; the movement produced by such means on the long lever is for throwing a stop 
 behind the traversing-frame and checking its further progress when not required, at the same time, 
 giving to it an elasticity by the application of a spiral spring, so as to prevent concussion. On the 
 means employed for throwing the driving-wheel H in and out of geer, depends the proper working of 
 the machine. The means of employing studs, as described, consist in fixing two peripheries together bv 
 pressing the projecting pins on one periphery into the opposite holes in the other ; for this object a side 
 lever with a forked end is placed in connection with the clutch-box on the main shaft, which it shifts 
 laterally within the limits of its fulcrum by the rotation of a cam placed on the sides of the toothed 
 wheel Y; this lever, so acted upon by the cam, requires a corresponding pressure to keep it up to its 
 work. To do this, the weight is applied and attached to it by a cord passing over the wheel Y and at- 
 tached to the lever, so that when the cam moves the end of the lever outwards the weight X will be 
 raised, but when it falls it will tend to move inward and throw out of geer the coupling disk aforesaid. 
 When motion is given to the driving-shaft B by E, and communicated through the train of toothed geer- 
 ing wheels to the main shaft F, such motion, in consideration of the parts arranged for such purposes, is 
 caused to move the traversing-frame by reason of the teeth of the wheel H taking into the teeth of the 
 horizontal rack, and propelling it in either direction by the reversing rack. The rollers may be made 
 of india-rubber and keot cool in a trough of cold water. 
 
 PRINTING-PRESS. We cannot do better under this head than to exhibit the various presses 
 manufactured for this purpose, by R. Hoe & Co., of New York. 
 
 Type-revolving, fast printing-machine. — Fig. 3112. A horizontal cylinder of about four and a half feet in 
 diameter is mounted on a shaft, with appropriate bearings ; about one-fourth of the circumference of this 
 cylinder constitutes the bed of the press — the periphery of which portion is adapted to receive the form 
 of types — the remainder is used as a cylindrical distributing table. The diameter of the cylinder is less 
 than that of the form of types, in order that the distributing portion of it may pass the impression cvl 
 inders without touching. The ink is contained in a fountain placed beneath the large cylinder, fro® 
 
520 
 
 PRINTING-PRESS. 
 
PRINTING-PRESS. 
 
 521 
 
 which it is taken by a ducter roller and transferred, by a vibrating distributing roller, to the cylindrical 
 distributing table ; the fountain-roller receives a slow and continuous rotary motion, to carry up the ink 
 from the fountain. 
 
 The large cylinder being put in motion, the form of types thereon is, in succession, carried to four or 
 more corresponding horizontal impression cylinders, arranged at proper distances around it, to give the 
 impression to four or more sheets, introduced one by each impression cylinder. The fly and feed boards 
 of two of the impression cylinders are similar to those on the well-known double-cylinder press ; on the 
 other two, the sheet is fed in below and thrown out above. The sheets are taken directly from the 
 feed-board by iron fingers attached to each impression cylinder. Between each two of the impression 
 cylinders there are two inking-rollers, which vibrate on the distributing surface while taking a supply 
 of ink, and at the proper time are caused to rise, by a cam, so as to pass over the form, when they 
 again fall to the distributing surface. Each page is locked up upon a detached segment of the large 
 cylinder, called by the compositors a “ turtle,” and this constitutes the bed and chase. The column-rules 
 run parallel with the shafts of the cylinder, and are consequently straight ; while the head, advertising, 
 and dash rules are in the form of segments of a circle. A cross-section of the column-rules would pre- 
 sent the form of a wedge, with the small end pointing to the centre of the cylinder, so as to bind the 
 types near the top ; for the types being parallel, instead of radiating from the centre, it is obvious that 
 if the column-rules were also parallel, they must stand apart at the top, no matter how tight they were 
 pressed together at the base ; but with these wedge-shaped column-rules, which are held down to the 
 bed or turtle by tongues, projecting at intervals along their length, and sliding in rebated grooves cut 
 crosswise in the face of the bed, the space in the grooves, between the column-rules, being filled with 
 sliding blocks of metal, accurately fitted, the outer surface level with the surface of the bed, the ends 
 next the column-rules being cut away underneath to receive a projection on the sides of the tongues, 
 and screws at the end and side of each page to lock them together, the types are as secure on this cyl- 
 inder as they can be on the old flat bed. 
 
 Fig. 3112 represents a press with four impression cylinders, capable of printing 10,000 impressions per 
 hour. Four persons are required to feed in the sheets, which are thrown out and laid in heaps by self- 
 acting flyers, as in the ordinary cylinder presses. A press with eight impression cylinders will print 
 16,000 or more impressions per hour. 
 
 Patent single large-cylinder printing-machine. — Fig. 3113. This machine is particularly adapted to 
 book and fine newspaper work. It has a registering apparatus and sheet-flyer; also adjustable iron 
 bearers, so that stereotype may be worked with the same facility and beauty as type forms. One boy 
 is required to lay on the sheets, and the press may be driven by man or steam power. With the same 
 attendance, it will print, say from 1,000 to 2,000 impressions in an hour, according to the size if the press 
 and the quality of the work desired. 
 
522 
 
 PRINTING-PRESS. 
 
 Single small- cylinder printing-machine.— Fig. 3114. In this press the form of types is placed upon a 
 flat bed, and the impression taken upon the paper by means of a cylinder, while the form is passing 
 undei it. I he small size of the cylinder allows the machine to be constructed in a very compact man- 
 ual* so as to shorten the distance which the bed travels, thereby considerably increasing the number ot 
 mnressions in a given time, beyond the single large-cylinder press. 
 
 This machine is of convenient height for use. One person only is required to feed down the paper 
 « hose position is but a step from the floor. It will give from 2,000 to 3,000 impressions per hour, with 
 perfect safety to the machinery. The printed sheets are thrown out by a fly-frame in a uniform pile. 
 Register sufficiently accurate for newspaper and job work is obtained by the patent feed-guides, which 
 are attached to each press. When required, a registering or pointing apparatus is furnished, and the 
 press may then be used advantageously for book-work. 
 
 The press is made in the same manner as the double-cylinder press described above, with buffers 
 similarly arranged to prevent noise. 
 
 Double-cylinder printing-machine. — Fig. 3115. In its arrangement this press is similar to the single 
 small-cylinder machine ; except that it has two impression cylinders each alternately giving an impression 
 from the same form. The sheets are supplied by two attendants, and, if required to print short editions 
 of various sizes, it will be necessary to have a boy at each end of the press to receive the printed sheets ; 
 but where large editions or forms of uniform size are worked, not requiring frequent changes of the 
 tape-wheels, the self sheet-flying apparatus is very efficient and economical, placing the printed 
 sheets in heaps with precision, and dispensing entirely with the two boys otherwise required for that 
 purpose. 
 
 The large amount of printing ordinarily done on these presses, and the consequent speed required 
 have rendered necessary greatly increased strength and weight of material in all the parts, together witl 
 
3115 
 
 PRINTING-PRESS, 
 
 523 
 
524 
 
 PRINTING-PRESS. 
 
 simplicity in the mechanical arrangements, and the utmost perfection of workmanship. The noise and 
 annoyance occasioned by the concussion of the bed against the springs, which are placed at each end ol 
 the machine to overcome the momentum of the bed, has been removed by means of adjustable india- 
 rubber buffers placed at the points of contact, which in no way interfere with the lively and certain 
 action of the spiral springs. 
 
 Patent machine card-press. — Fig. 3116. For printing cards and small circulars, this machine is not 
 surpassed. It is worked by either a crank or treadle, and will print from 1,000 to 1,500 cards per hour 
 and may be used also for printing note-paper and small circulars. Its feeding apparatus for cards is 
 self-acting. Size of chase inside 61 by 5 inches. 
 
 3116. 
 
 Improved lithographic-press . — Fig. 3117. This is believed to be the best press in use for lithographic 
 printing. The side-rods and top beam are made of wrought-iron ; the bed and stone are raised to the 
 scraper by a lever and steel cam, working on a steel friction-roller; the impression is regulated by a 
 
 single screw through the top beam ; the scraper is hung on a pivot, that it may accommodate itself to 
 inequalities in the surface of the stone ; the bed is made of the toughest ash plated with iron, with iroit 
 
PROJECTION. 
 
 525 
 
 runners, which run on friction-rollers; the tympan-frame is wrought-iron, with screws and nuts for 
 stretching the tympan. The larger sizes are geered, so as to enable the printer to take an impression 
 from the largest stone with ease. 
 
 Copperplate-press . — 3118. The side-frames, cylinders, and bed are made of cast-iron; the cylinders 
 are turned and the bed planed perfectly true. The shafts through the cylinders, the braces, arms, and 
 6crews, are of wrought-iron, the bearings of composition. 
 
 PROJECTION Projections are of various kinds, according to the situations in which the eye is 
 supposed to be placed in respect of the body and the plane on which it is to be projected ; but there 
 are three which, by reason of the frequency of their use, are particularly deserving of attention, namely 
 the orthographic , the stereographic, and the central or gnomonic. 
 
 1. Orthographic projection. — In this projection the eye is supposed to be at an infinite distance, and 
 the plane of projection, i. e., the plane on which the representation is made, perpendicular to the direc- 
 tion of the rays of light, which are all parallel to each other. The laws of this projection are easily 
 deduced. 1. Any point in space is projected by drawing a straight line from it perpendicular to the 
 plane of projection. 2. A straight line perpendicular to the plane of projection is projected into a point. 
 A straight fine parallel to the plane of projection is projected into an equal straight line ; and a straight 
 line inclined to the plane of projection, is projected into a straight line which is shorter than the first in 
 the proportion of the cosine of the angle of inclination to radius. 3. A plane surface perpendicular to 
 the plane of projection is jsrojected into a straight line. 4. A circle parallel to the plane of projection 
 is projected into an equal circle ; but a circle oblique to the plane of projection is projected into an 
 ellipse, of which the greater axis is equal to the diameter of the circle, and the lesser axis is equal to 
 that diameter multiplied by the cosine of the obliquity. 
 
 The orthographic projection has a multitude of applications. The plans and sections by which arti- 
 ficers execute their different constructions are orthographic projections of the things to be constructed ; 
 and a solid body may be represented in all its dimensions by orthographic projections on two planes at 
 right angles to each other. 
 
 2. Stereographic projection of the sphere . — In this projection the eye is supposed to be situated at the 
 surface of the sphere, and the plane of projection is that of the great circle, which is everywhere 90° 
 from the position of the eye. 
 
 Two of the principal properties of this projection are the following : 1. The projection of any circle on 
 the sphere which does not pass through the eye is a circle ; and circles whose planes pass through the 
 eye are projected into straight lines. 2. The angle made on the surface of the sphere by two circles 
 which cut each other, and the angle made by their projections, is equal. 
 
 3. Gnomonic or central projection . — In this projection the eye is situated at the centre of the sphere, 
 and the plane of projection is a plane which touches the sphere at any point assumed at pleasure. The 
 
526 
 
 PROVING- MACHINE, HYDROSTATIC. 
 
 point of contact is called the principal point ; and the projections of all other points on the sphere are 
 at the extremities of the tangents of the arcs intercepted between them and the principal point. As 
 the tangents increase very rapidly when the arcs exceed 45°, and at 90° become infinite, the central 
 projection cannot be adopted for a whole hemisphere. 
 
 PROVING MACHINE, HYDROSTATIC, for proving chain-cables. Figs. 3119, 3120, 3121. and 
 3122 represent a machine designed and constructed by Wm. M. Ellis, engineer, United States Navv 
 Yard, Washington. 
 
 A A, plan, Fig. 3119, water cistern, with three force-pumps 
 
PUDDLER’S BALLS. 
 
 527 
 
 B, hydrostatic cylinder. C C, wrought-iron cross-heads. D D, wrought-iron bars, connecting cross 
 heads 0 C. F, granite sills. 
 
 H, screw-wheel, for forcing back the ram. 
 
 E, Fig. 3120, compound levers, for ascertaining the strain: proportion, 1 to 200. Fig. 3122, section. 
 
 PUDDLER’S BALLS, MACHINE FOR COMPRESSING, by J. F. Winslow, Troy, N. Y. In Fig 
 3 1 22|, A is the rotating cam-formed compresser. B B, two cylindrical bed-rollers. C, leop or ball of iron, 
 resting upon and between the two bed-rollers in position for being compressed by the rotating cam A. 
 D, helical shaped cam, keyed on to the neck of one of the bed-rollers B and revolves with it, and 
 
528 
 
 PUMPS. 
 
 ■which forces outward the ram or hammer E, which, when released from the cam, a powerful helical 
 spring which is inserted into a cavity in the outer end of the ram throws forward against the loop ol 
 iron and upsets it— the opposite end of the loop, or ball, or bloom being supported against the heavy 
 flanch F, which is cast upon one of the bed-rollers, and serves as an anvil against which to upset or 
 hammer the blooms. G, spur-wheel on the end of the shaft that supports the cam A. H, spur-pinion 
 on the driving-shaft I. This pinion works into two others of corresponding size, one on the end of each 
 bed-roller. This driving-pinion H being interposed between the two on the bed-rollers and the spur- 
 wheel G, gives the peripheries of all the rollers and the cam a direction the reverse of the periphery 
 of the ball C, and all being in motion no waste or abrasion of the hot iron can ensue, as the ball must 
 necessarily revolve upon its axis and be retained in proper place between the rollers and compressers 
 I, shipping-bar. J, shaft communicating with the driving power. 
 
 Advantages. — 1 . Great expedition in shingling puddlers’ iron, one of these machines being sufficient 
 to do the work for 25 puddling furnaces. 2. The almost entire saving of shinglers’ wages. 3. No 
 waste of iron — turning out the blooms while very hot, enabling the roller to reduce them to very 
 smooth and sound bars. 4. Scarcely no expense for repairs. 5. A very small amount of power re- 
 quired to operate it. 6. The ends of the blooms being thoroughly upset. 
 
 PULLEY. See Mechanical Powers. 
 
 PUMPS. — The common pump. Fig. 3123 represents a section of the common suction pump. 
 A 0 is a cylinder or barrel, in which a piston P is moved up and down by means of a piston-rod R, 
 attached to the extremity of the lever, R H, of the first kind. In the piston is a valve v lifting 
 upwards ; and at the bottom of the barrel is another valve V, also lifting upwards. A B is a pipe, 
 passing from the bottom of the barrel into the well from which the water is to be raised. 
 
 In the downward stroke of the piston, it plunges amongst the water in the barrel of the pump; the 
 valve Y closes, and the valve v opens, and allows the water to pass to the upper side of the piston. 
 In an upward stroke the valve v closes, and the valve V opens, and, by the pressure of the atmos- 
 phere, the water follows the piston in its ascent, whereas the water above the piston is pushed before 
 it, and thus the fluid is discharged in a stream at the mouth C of the pump ; and so on to any num- 
 ber of strokes. 
 
 If a perfect vacuum were formed by the piston as it ascends, the water would be raised, on an aver- 
 age, to the height of 34 feet above the level of the water in the well, which is the height of a column 
 of water calculated to balance the average pressure of the atmosphere. 
 
 3124. 
 
 The common forcing pump. — This pump, Fig. 3124, raises water from the well into the barrel on the 
 principle of the suction pump just described, Fig. 3123, and then the pressure of the piston on the 
 water elevates it to any height that may be required. 
 
 Here Pisa solid piston working up and down in a barrel ; Y a valve, lifting upwards, placed at the 
 top of the pipe descending into the well ; v a valve, also lifting upwards, placed in a pipe D, which 
 conveys the water to the cistern. 
 
 In a descending stroke of the piston, the valve Y closes and the valve v opens, and the water, being 
 pressed before the piston, is forced up the pipe D to the higher level required; on the contrary, in an 
 ascending stroke, the valve v closes by the pressure of the external air and the water in the pipe D ; 
 the valve V opens, and the water rises into the barrel of the pump by the pressure of the atmosphere 
 on the water in the well ; and so on to any number of strokes. 
 
 The forcing pump with an air-chamber. — This engine, Fig. 3125, merely differs from the preceding 
 one by having an air-chamber ecv connected with the vertical pipe D. This air-chamber is a closea 
 vessel, having the pipe D descending into it, and a valve v opening and closing its communication with 
 the barrel of the pump. When the piston P descends, the water is forced through the valve v into 
 the air-chamber, so that as soon as the water rises above the lower orifice of the pipe D, the air in the 
 upper part of the chamber is contracted or compressed ; and this compression ot the air causes it to 
 
PUMPS. 
 
 529 
 
 exert a continuous pressure upon the surface of the water in the chamber, which forces the fluid up 
 the pipe D, and thus a constant discharge into the cistern is sustained. In the common forcing pump 
 the water is only discharged at each downward stroke of the piston, whereas, in the present case, the 
 pressure of the air in the chamber sustains the discharge through the vertical pipe D during the in- 
 tervals taken up by the upward strokes of the piston. 
 
 The great defect of this engine is as follows : — after the pump lias been some time in action the air 
 in the chamber becomes absorbed by the water passing through it, so that at length it is found that 
 nearly all the air at first in the chamber has passed away with the water discharged by the pump. 
 
 Double-acting pump . — This pump, Fig. 3120, is designed to remedy the defect of the preceding one. It 
 is simply a double-acting forcing pump. P is a solid piston which moves up and down in a cylinder ; the 
 rod of this piston passes through a stuffing-box at S for the purpose of keeping the cylinder air-tight. On 
 the opposite sides of the cylinder are two pipes A 11 and 0 D ; where A B descends into the well, and 
 C D conveys the water to the reservoir. There are four valves ab e c opening and closing, as the case 
 may be, the communication of these pipes with the cylinder. These valves all lift in the same direc- 
 tion, that is, to the right. Suppose the cylinder and pipes filled with water, then in an upward stroke 
 of the piston, the valves a and e are opened, and c and b are closed ; the water is forced by the piston 
 through the valve e and then up the vertical pipe C D ; at the same time the water, by the atmospheric 
 pressure, rises up the pipe A, and opening the valve a follows the piston in its ascent : on the contrary, 
 when the piston descends, the valves a and e are closed, and c and b are opened ; the water is then 
 forced through the valve c, up the vertical pipe C 1), and the water from the well enters the cylinder 
 through the valve b, and follows the piston in its descent ; and so on to any number of strokes. 
 
 3125. 
 
 3120. 
 
 
 Is 
 
 jp 
 
 T-S- 
 
 ' rfj _ 
 
 
 
 A 
 
 -tr 
 
 It 
 
 |f- 
 
 III 
 
 
 : r 
 
 
 
 J 
 
 rn 
 
 3127. 
 
 1A 
 
 Another variation of the forcing pump, called a plunger-pump, Fig. 312*1, consists 
 in making the piston of the same length as the cylinder but rather less in diame- 
 ter, so that it may be moved freely in the former without touching the sides. These 
 pistons are made wholly of metal, and turned smooth and cylindrical, so as to 
 work through a stuffing-box or cupped leathers. The quantity of water raised at 
 each stroke has therefore no reference to the capacity of the cylinder, however large that part of one 
 of these pumps may be, for the liquid displaced by the piston can only be equal to that part of the lat 
 ter that enters the cylinder. It is immaterial at what part of the cylinder the forcing or ascending pipe 
 is_ attached, whether at the bottom, near the top, or at any intermediate place. Small pumps of this 
 kind are now commonly employed to feed steam boilers and for other purposes, and are worked by 
 levers like the ordinary lifting and forcing pumps, the pistons being preserved in a perpendicular posi- 
 tion by slings. 
 
 This is one of the most valuable modifications of the forcing pump. The friction of the piston is not 
 only greatly reduced, but the boring of the cylinder is dispensed with ; an operation of considerable ex- 
 pense and difficulty, particularly so, before efficient apparatus for that purpose was devised. Another ad- 
 vantage is the facility of tightening the packing without taking out the piston or even stopping the pump. 
 
 There is another species of plunger-pumps, Fig. 3128, in which the stuffing-box is dispensed with, and 
 consequently the piston works without friction. A square wooden tube, or a common pump log of suffi- 
 cient length, and with a valve at its lower end, is fixed in the well as shown in Fig. 3128. The depth 
 of the water must be equal to the distance from its surface to the place of delivery ; and a discharging 
 pipe having a valve opening upwards is united to the pump tree at the surface of the water in the well 
 The piston (a solid piece of wood) is suspended by a chain from a working beam, and loaded sufficiently 
 with weights to make it sink. As the liquid enters the pump through the lower valve, and stands at 
 the^ same level within as without, whenever the piston descends, it necessarily displaces the water, 
 which has no other passage to escape but through the discharging pipe, in consequence of the lower 
 valve closing. And when the piston is again raised as in the figure, a fresh portion of water enters tho 
 pump and is driven up in like manner. 
 
 Vol. II.— 3+ 
 
530 
 
 PUMPS. 
 
 Fig. 3129 is a pump to raise -water without any friction of solids; making use of quicksilver instead 
 of leather to keep the air or water from slipping by the sides of the pistons. One form of it is repre- 
 sented by the figure. A is the suction-pipe, the lower end of which is inserted in the water to be raised. 
 Its upper end terminates in the chamber C, and is covered by a valve. The forcing-pipe B, with a valve 
 at its lower end, is also connected to the chamber. Between these valves a pipe, open at both ends, is 
 inserted and bent down, as in the figure. The straight part attached to it is the working cylinder of 
 the pump, and should be made of iron. Another iron pipe, a little larger in the bore than the last, and 
 of the same length, is made to slide easily over it. This pipe is closed at the bottom and suspended by 
 chains or cords, by which it is moved up and down. Suppose this pipe in the position represented, and 
 tilled with mercury — if it were then lowered, the air in the cylinder and between the valves would be- 
 come rarified, and the atmosphere pressing on the surface of the water in which the end of A is placed, 
 would force the liquid up A till the density of the contained air was the same as before ; then by rais- 
 ing the pipe containing the mercury, the air, unable to escape through the lower valve, would be forced 
 through the upper one ; and by repeating the operation, water would at last rise and be expelled in the 
 same way, •provided the elevation to which it is to be raised does not exceed thirteen times the depth 
 of the mercurial column around the cylinder ; the specific gravity of quicksilver being so many times 
 greater than that of water. When the depth of the former is 30 inches, the latter may be raised as 
 many feet in the suction-pipe and forced up an equal distance through the forcing one, making together 
 an elevation of sixty feet; but if water be required higher, the depth of the mercurial column in the 
 movable pipe must be proportionably increased. To make a small quantity of mercury answer the 
 purpose, a solid piece of wood or iron that is a little less than the cylinder is secured to the bottom oi 
 the movable vessel as shown in the centre : this answers the same object as an equal bulk of mercury. 
 
 These pumps have their disadvantages : they are expensive : and however well made, the quantity 
 of quicksilver required is considerable — the agitation consequent on the necessary movement soon con- 
 verts it into an oxide and renders it useless. Great care is also required in working these machines : it 
 
 the movements are not slow and regular, the mercury is very apt to be thrown out ; to prevent which 
 the upper end of the vessel containing it is dished or enlarged. For the reasons above stated, they 
 have never been extensively employed in the arts. 
 
 If a common atmospheric pump be inverted, as shown in Figs. 3130 and 3131, its cylinder immersed 
 in water, and the valves of the upper and lower boxes reversed, it becomes a forcing, or, as it is some- 
 times named, a lifting pump ; because the contents of the cylinder are lifted up when the piston is 
 raised, instead of being driven out from below by its descent. In a lifting pump the liquid is expelled 
 from the top of the cylinder— in a forcing one from the bottom : it is the water above the piston that is 
 raised by the former ; and that which enters below it, by the latter. The piston-rod in the figure is at- 
 tached to an iron frame that is suspended to the end of a beam or lever. The valve on the top of the 
 piston, like that at the end of the cylinder, opens upwards. When the piston descends (which it does 
 by its own weight and that of the frame) its valve opens and the water enters the upper part of the 
 cylinder, then as soon as it begins to rise its valve closes, and the liquid above it is forced up the as- 
 cending pipe. Upon the return of the piston the upper valve is shut by the weight of the column above 
 it, the cylinder is again charged, and its contents forced up by a repetition of the movements. Machines 
 of this description are of old date. They were formerly employed in raising water from mines. 
 
 Lifting pump . — The modern form of this pump is represented in Fig. 3132. The working cylinder 
 being generally metal, and having a strong flanch at each end ; the upper one is covered bv a plate 
 with a stuffing-box in the centre through which the polished piston-rod moves ; and the under one bv 
 mother to which the suction-pipe is attached, and whose orifice is covered by a valve. 
 
PUMPS. 
 
 531 
 
 The fire-engine . — This engine, Fig. 3183, is simply a combination of two forcing pumps, having a 
 common air-chamber H, and the same suction-pipe F descending to the water intended to supply the 
 engine. The beam A B, turning on its centre of motion K, works the two pistons C and D ; so that 
 while the one is descending the other is ascending, thereby keeping up a continuous flow of water into 
 the air-chamber H. A flexible tube E, of leather, called a hose, is attached to the discharge-pipe, to 
 enable the engine-man to direct the stream of water upon any particular spot. The degree of compres- 
 sion attained by the air in the chamber regulates the velocity with which the water is projected from 
 the nozzle L of the hose. 
 
 If, for example, the air be compressed to one half its original bulk, then it will act upon the surface 
 of the water in the chamber with a pressure equivalent to that of the atmosphere, and the water would 
 be raised in the pipe E to the height of about 34 feet, or it would be projected from the nozzle L with 
 a velocity equal to that winch a body would acquire in falling freely, by the force of gravity, from this 
 height. 
 
 3131. 
 
 SI 32. 
 
 3133. 
 
 The chain pump . — This engine, Fig. 3184, consists of a continuous chain 
 A B C, to which are attached a series of pistons or buckets for raising the water. 
 This chain passes downwards through the wooden tube E, and returns up>- 
 wards through C, extending over two sprocket wheels Q and J. The arms or 
 teeth of the upper wheel Q, acting upon the notches or teeth cut upon the 
 links of the chain, put the chain of pistons or buckets in motion. The lower 
 portion C D of the ascending tube is lined with a brass barrel, in which the 
 pistons or buckets are fitted ; so that whilst they are ascending through this 
 barrel, the water is lifted and discharged at the top A of the tube. The 
 wheel Q is turned by a winch, a shows the shape of the links forming the chain, b the section of the 
 piston or buckets. 
 
 Rotary pumps . — Two cog-wheels, the teeth of which are fitted to work accurately into each other, 
 are inclosed in an elliptical case. The sides of these wheels turn close to those of the case, so that 
 water cannot enter between them. The axle of one of the wheels is continued through one side of the 
 case, (which is removed in the figure to show the interior,) and the opening made tight by a stuffing- 
 box or collar of leather. A crank is applied to the end to turn it, and as one wheel revolves, it ne- 
 cessarily turns the other ; the direction of their motions being indicated by the arrows. The water 
 that enters the lower part of the case is swept up the ends by each cog in rotation, and as it cannot 
 return between the wheels in consequence of the cogs being there always in contact, it must neces- 
 sarily rise in the ascending or forcing pipe. The machine is, therefore, both a sucking and forcing one. 
 Of rotary pumps this is not only one of the oldest, but one of the best. Fire-engines made on the same 
 plan were patented about twenty-five years ago in England, and more recently pumps of the same 
 kind in this country. 
 
 Rotary pumps may be divided into classes according to the forms of and methods of working the 
 pistons, or those parts that act as such ; and according to the various modes by which the hutment is 
 obtained. It is tills last that receives the force of the water when impelled forwards by the jiiston ; 
 it also prevents the liquid from being swept by the latter entirely round the cylinder or exterior case, 
 and compels it to enter the discharging pipe. In these particulars consist all the essential differences 
 in rotary pumps. In some the hutments are movable pieces that are made to draw back to allow the 
 piston to pass, when they are again protruded till its return ; in others they are fixed, and the pistons 
 themselves give way. It is the same witli the latter; they are sometimes permanently connected to 
 the axles by which they are turned, and sometimes they are loose and drawn into recesses till the 
 butments pass by. In another class the pistons are rectangular, or other shaped pieces that turn on 
 centres, something like the vanes of a horizontal wind-mill, sweeping the water with their broad faces 
 round the cylindrical case, till they approach that part which constitutes the hutment, when they move 
 edgeways and pass through a narrow space which they entirely fill, and thereby prevent any watet 
 
532 
 
 PUMPS. 
 
 passing with them. In other pumps the butment is obtained by the contact of the peripheries of two 
 wheels or cylinders, that roll on or rub against each other. Fig. 3135 is of this kind : while the teeth 
 in contact with the ends of the case act as pistons in driving the water before them, the others are 
 fitted to work so closely on each other as to prevent its return. Fig. 3136 exhibits another modifiea- 
 lion of the same principle. 
 
 Eve's patent rotary steam-engine and pump . — Within a cylindrical case a solid or hollow drum A, 
 Fig. 3136, is made to revolve, the sides of which are fitted to move close to those of the case. Three 
 projecting pieces or pistons, of the same width as the drum, are secured to or cast on its periphery : 
 they are at equal distances from each other, and their extremities sweep close round the inner edge 
 of the case, as shown in the figure. The periphery of the drum revolves in contact with that of a 
 smaller cylinder B, from which a portion is cut off to form a groove or recess sufficiently deep to re- 
 ceive within it each piston as it moves past. The diameter of the small cylinder is just one-third that 
 of the drum. The axles of both are continued through one or both sides of the case, and the openings 
 made tight with stuffing-boxes. On one end of each axle is fixed a toothed wheel of the same diam- 
 eter as its respective cylinder ; and these are so geered into one another, that when the crank attached 
 
 to the drum-axle is turned (in the direction of the arrow) the groove in the small cylinder receives 
 successively each piston ; thus affording room for its passage, and at the same time by the contact of 
 the edge of the piston with its curved part, preventing water from passing. As the machine is worked, 
 the water that enters the lower part of the pump through the suction-pipe, is forced round and com- 
 pelled to rise in the discharging one, as indicated by the arrows. Other pumps of the same class have 
 such a portion of the small cylinder cut off, that the concave surface of the remainder forms a contin- 
 uation of the case in front of the recess while the pistons are passing ; and then by a s imilar movement 
 
PUMPS. 
 
 as that used in the figure described, the convex part is brought in contact with the periphery of the 
 drum till the piston’s return. 
 
 All rotary pumps are both sucking and forcing machines, and are generally furnished with valves in 
 both pipes, as in the ordinary forcing pumps. The butments are always placed between the apertures 
 of the sucking and forcing pipes. 
 
 There is another class of pumps that bears some relationship to the preceding ; one of these is shown 
 in Fig. 3137. The butment consists of a curved flap that turns on a hinge ; it is so arranged as to be 
 received into a recess formed on the rim or periphery of the case, and into which it is forced by the 
 
 E iston. The concave side of the flap is of the same curve as the rim of the case, and when pushed 
 ack forms a part of it. Its width is, of course, equal to that of the drum, against the rim of which 
 its lower edge is pressed ; this is effected in some pumps by springs, in others by cams, cog-wheels, 
 &c., fixed on the axles, as in the last one. The force by which the flap is urged against the drum must 
 exceed the pressure of the liquid column in the discharging pipe. The semicircular pieces on the outer 
 edge of the case represent ears for securing the pump to planks or frames, &c., when in use. The ar- 
 rows in the figures show the direction in which the piston and water is moved. 
 
 Nearly a hundred years before the date of Watt’s patent, Amontons communicated to the French 
 Academy a description of a rotary pump substantially the same as represented in Fig. 3187. It is, 
 figured and described in the first volume of Machines Approuv ., p. 103 : the body of the pump or case 
 is a short cylinder, but the piston is elliptical, its transverse diameter being equal to that of the cyl- 
 inder, hence it performed the part of two pistons. There are also two flaps on opposite sides of the 
 cylinder. 
 
 In other pumps the flaps, instead of acting as butments, are made to perform the part of pistons ; 
 this is done by hinging them on the rim of the drum, of which, when closed, they also form a part : 
 they are closed by passing under a permanent projecting piece or butment that extends from the case 
 to the drum. 
 
 In Fig. 3138 the butment is movable. A solid wheel, formed into three spiral wings that act as 
 pistons, is turned round within a cylindrical case. The butment B is a piece of metal whose width is 
 equal to the thickness of the wings, or the interior breadth of the cylinder ; it is made to slide through 
 a stuffing-box on the top of the case, and by its weight to descend and rest upon the wings. Its upper 
 part terminates in a rod, which, passing between two rollers, preserves it in a perpendicular position. 
 As the wheel is turned, the point of each wing (like the cogs of the wheel in Fig. 3135) pushes before 
 it the water that enters the lower part of the cylinder, and drives it through the valve into the as- 
 cending pipe A ; at the same time the butment is gradually raised by the curved surface of the wing, 
 and as soon as the end of the latter passes under it, the load on the rod causes it instantly to descend 
 upon the next one, which in its turn produces the same effect. This pump is as old as the 16th cent- 
 ury, and probably was known much earlier. Besides the defects common to most of its species, it has 
 one peculiar to itself: as the butment must be loaded with weights sufficient to overcome the pressure 
 of the liquid column over the valve, (otherwise it would itself be raised and the water would escape 
 beneath it;) the power to work this pump is therefore more than double the amount which the water 
 forced up requires. The instrument is interesting, however, as affording an illustration of the early use 
 of the sliding-valve and stuffing-box; and as containing some of the elements of recent, rotary pumps 
 and steam-engines. 
 
 The pump represented by Fig. 3139 consists also of an exterior case or short cylinder within which 
 a small and solid one A is made to revolve. To the last an arm or piston is attached or cast in one 
 piece with it, the sides and ends of which are fitted to bear slightly against the sides and rim in the 
 case. A butment B B slides backwards and forwards through a stuffing-box, and is so arranged (by 
 means of a cam or other contrivance connected to the axle of the small cylinder on the outside of the 
 case) that it can be pushed into the interior as in the figure, and at the proper time be drawn back to 
 afford a passage for the piston. Two openings near each other are made through the case on opposite 
 sides of BB, and to these the suction and forcing pipes are united. Thus when the piston is moved in 
 the direction of the arrow on the small cylinder, it pushes the water before it, and the vacuity formed 
 behind is instantly filled with fresh portions driven up the suction-pipe by the atmosphere ; aud when 
 the piston in its course descends past BB it sweeps this water up the same wav 
 
584 
 
 PUMPS. 
 
 Fig. 3140 represents another rotary engine. This is also a reinvention. Lure many others, it con 
 gists of two concentric cylinders or drums, the annular space between them forming the pump-chamber 
 but the inner one, instead of revolving as in the preceding figures, is immovable, being fixed to the 
 6ides of the outer one or case. The piston is a rectangular and loose piece of brass or other metal 
 accurately fitted to occupy and move in the space between the two cylinders. To drive the piston, 
 and at the same time to form a hutment between the orifices of the induction and eduction pipes, a 
 third cylinder is employed, to which a revolving motion is imparted by a crank and axle in the usual 
 way. This cylinder is eccentric to the others, and is of such a diameter and thickness that its interior 
 and exterior surfaces touch the inner and outer cylinders, as represented in the cut, the places of con- 
 tact preventing water from passing : a slit or groove equal in width to the thickness of the piston is 
 made tlirough its periphery, into which slit the piston is placed. When turned in the direction of 
 the large arrow, the water in the lower part of the pump is swept round and forced up the rising pipe, 
 and the void behind the piston is again filled by water from the reservoir into which the lower pipe 
 is inserted. This machine was originally designed, like most rotary pumps, for a steam-engine. 
 
 In others the pistons slide within a revolving cylinder or drum that is concentric with the exterior 
 one. Fig. 3141 is a specimen of a French pump of this kind. The hutment in the form of a segment 
 ■is secured to the inner circumference of the case, and the drum turns against it at the centre of the 
 chord line ; on both sides of the place of contact it is curved to the extremities of the arc, and the 
 sucking and forcing pipes communicate with the pump through it, as represented in the figure. To 
 the centre of one or both ends of the case is screwed fast a thick piece of brass whose outline resem- 
 bles that of the letter D ; the flattened side is placed towards the butment, and is so formed that the 
 same distance is preserved between it and the opposite parts of the butment, as between its convex 
 surface and the rim of the case. The pistons, as in the last figure, are rectangular pieces of stout 
 metal, and are dropped into slits made through the rim of the drum, their length being equal to that 
 of the case, and their width to the distance between its rim and the D piece. They are moved by a 
 crank attached to the drum-axle. To lessen the friction and compensate for the wear of the butment, 
 that part of the latter against which the drum turns is sometimes made hollow ; a piece of brass is let 
 into it and pressed against the periphery of the drum by a spring. 
 
 In Fig. 3142 the axis of the drum or smaller cylinder is so placed as to cause its periphery to rub 
 against the inner circumference of the case. Two rectangular pistons, whose lengths are equal to the 
 internal diameter of the case, cross each other at right angles, being notched so as to allow them to 
 slide backwards and forwards to an extent equal to the widest space between the two cylinders. The 
 case of this pomp is not perfectly cylindrical, but of such a form that the four ends of the pistons are 
 always in contact with it. An axle on the drum is moved by a crank. Fire-engines have been made 
 on the same principle. 
 
 Rotary pumps are as yet too complex and too easily deranged to be adapted for common use. To 
 make them efficient, their working parts require to be adjusted to each other with unusual accuracy 
 and care : their efficiency is, by the unavoidable wear of those parts, speedily diminished or destroyed. 
 The expense of keeping them in order exceeds that of others ; and they cannot be repaired by ordi 
 nary workmen, since peculiar tools are required for the purpose. 
 
 This remark holds true of all the rotary pumps we have seen, including Gwynne’s, wdiich is nothing 
 more than Dimpfel’s fan, Fig. 1612, applied to raising water ; it is without the merit of novelty in prin- 
 ciple, and in practice will be found worthless for the reasons above given. 
 
 Reciprocating rotary pumps . — One of the obstacles to be overcome in making a rotary pump, is the 
 passage of the piston over the butment, or over the space it occupies. The apparatus for moving the 
 butment as the piston approaches to or recedes from it, adds to the complexity of the machine ; nor is 
 this avoided when that part is fixed, for an equivalent movement is then required to be given to the 
 piston itself in addition to its ordinary one. In reciprocating rotary pumps these difficulties are avoid- 
 ed by stopping the piston when it arrives at one side of the butment, and then reversing its motion 
 towards the other ; hence tjiese are less complex than the former. They are, however, liable to some 
 of the same objections, being more expensive than common pumps, more difficult to repair, and upon 
 the whole less durable. 
 
 Fig. 3143 consists of a close case of the form of a sector of a circle, having an opening at the bottom 
 for the admission of w T ater, and another to which a forcing-pipe with its valve is attached. A movable 
 
PUMPS. 
 
 535 
 
 radius or piston is turned on a centre by a lever as represented ; thus, when the latter is pulled down 
 towards the left, the former drives the contents of the case through the valve in the ascending pipe. 
 
 Fig. 3144 consists of a short horizontal cylinder; a portion of the lower part is separated from the 
 rest by a plate where the suction-pipe terminates in two openings that are covered by clacks cc. The 
 partition A extends through the entire length of the cylinder, and is made air and water tight to both 
 ends, and also to the plate upon which its lower edge rests. The upper edge extends to the under 
 side of the axle to which the piston B is united. One end of the axle is passed through the cylinder, 
 and the opening made tight by a stuffing-box ; it is moved by a crank or lever. Near the clacks c c two 
 other openings are made through the plate, to which the forcing-pipes are 
 secured. These tubes are bent round the outside of the cylinder and meet 
 in the chamber C, where their orifices are covered by clacks. Thus when 
 the piston is turned in either direction, it 
 drives the water before it through one or 
 other of these tubes ; at the same time the 
 void left behind it is kept filled by the 
 pressure of the atmosphere on the surface 
 of the liquid in which the lower orifice of 
 the suction-pipe is placed. The edges of 
 the pistons are made to work close to the 
 ends and rim of the cylinder by means of 
 strips of leather screwed to them. Modi- 
 fications of these pumps have also been 
 used in England as fire engines. Watt 
 patented one in 1782 for a steam engine. 
 
 Centrifugal Pumps. If a common blow- 
 ing fan be immersed in water, and put in 
 operation, the water will be forced to the 
 periphery of the wheel, and may be ele- 
 vated in a rising main according to the 
 velocity given to the fan. Fig. 3145 rep- 
 resents a side rim of Appold’s centrifugal 
 pump as exhibited at the World’s Fair in 
 London. It consists of a hollow disk or cylinder, 12 inches diameter and 3 inches wide on the rim, with a 
 circular opening in the centre of 6 inches diameter. This cylinder is inclosed on both sides, excepting the 
 central opening, and is entirely open all round the rim. The disk is placed vertically on a shaft passing 
 through its centre, and on the end of this shaft is fixed a pulley for driving it. In order to raise the 
 water, the disk is placed in the bottom of a vertical trunk, as shown in fig. 3146. 
 
 In the centrifugal pump, the velocity of the circumference must be constant for all sizes of pumps 
 ior the same height of lift ; that is, a pump 1 inch diameter must make twelve times the number of 
 revolutions per minute of one 12 inches diameter, and both pumps will then raise the water to the same 
 height, but the quantity of water delivered will he 144 times greater than the 12 inch pump, being in 
 proportion to the area of the discharging orifices at the circumference, or the square of the diameter, 
 when the proportion of breadth was kept the same, namely, one fourth of the diameter in each case. 
 
 In Mr. Appold’s pump, a velocity of 500 feet per minute of the circumference raised the water 1 foot 
 high, and maintained it at that level without discharging any ; and a double velocity raised the water to 
 "our times the height, as the centrifugal force was proportionate to the square of the velocity ; conse- 
 quently, 
 
 500 feet per minute raised the water 1 foot without discharge. 
 
 1.000 “ “ “ 4 “ “ 
 
 2.000 “ “ “16 “ “ 
 
 4,000 “ “ “ 64 “ “ 
 
 The greatest height to which the water had been raised, without discharge, in the experiments with the 
 1 foot pump, was 67’7 feet, with a a velocity of 4,153 feet per minute, beiijg rather less than the calcu- 
 lated height, owing probably to leakage with the greater pressure. 
 
 A velocity of 1,128 feet per minute raised the water 54 feet without any discharge, and the maximum 
 effect from the power employed in raisins: to the same height 54 feet, was obtained at the velocity af 
 
536 
 
 PUMPS. 
 
 1,678 feet per minute, giving a discharge of 1,400 gallons per minute from the 1 foot pump. The ad- 
 ditional velocity required to effect the discharge is 550 feet per minute ; or the velocity required to 
 effect a discharge of 1,400 gallons per minute, through a 1 foot pump, working at a dead level without 
 any height of lift is 550 feet per minute : consequently, adding this number in each case to the velocity 
 given above at which no discharge takes place, the following velocities are obtained for the maximum 
 effect to be produced in each case : 
 
 1,050 feet per minute, velocity for 1 foot height of lift. 
 
 1.550 “ “ “ 4 feet “ 
 
 2.550 “ “ “ 16 “ 
 
 4.550 “ “ “ 64 “ “ 
 
 Or, in general terms, the velocity in feet per minute for the circumference of the pump to he driven to 
 raise the water to a certain height, is equal to 
 
 550 + (500 f height of lift in feet). 
 
 In some situations where it is the most important consideration for a pump to be quickly and readily 
 applied, that would discharge a very large quantity of water, the centrifugal pump is found very advan- 
 tageous in such cases. In one instance, in putting in the foundations of harbor works at Dover, a large 
 quantity of water of 2,000 to 3,000 gallons per minute was pumped out by one of these pumps. The 
 centrifugal pump had another important advantage for such applications, from having no valves in 
 action when at work, which enabled it to pass large stones, and almost anything that was not too large 
 to enter between the arms. The largest pump constructed at present on this plan was erected at Whit- 
 tlesea Mere, for the purpose of draining, and has worked there nearly a year with complete success. The 
 pump is 4£ feet diameter, with an average velocity of 90 revolutions, or 1,250 feet per minute, and is 
 driven by a double-cylinder steam-engine, with steam 40 lbs. per inch, and vacuum 134 lbs. per inch ; 
 it raises about 15,000 gallons of water per minute an average height of four or five feet. 
 
 Mr. Appold considers the spiral form of the arms an essential point in his pump, instead of the radial 
 arms in the other centrifugal pumps. He at first tried straight arms inclined at 45°, but he found 
 that the curved arms ending nearly in a line with a tangent to the outer circumference gave the greatest 
 effect. 
 
 The comparative value of the different forms of arms was proved by the experiments at the London 
 Exhibition mentioned before ; the curved arms gave a duty of 68 per cent., the inclined arms 43 per 
 cent., and the radial arms only 24 per cent. 
 
 The Spiral Pump. If we wind a pipe round a cylinder, of which the axis is horizontal, and connect 
 one end with a vertical tube, while the other is at liberty to turn round and receive water and air in each 
 revolution, the machine is called a spiral pump ; it was invented, about 1746, by Andrew Wirz, a pew- 
 terer in Zurich, and was employed at Florence with Bernoulli’s improvement, in 1779. At Archangel- 
 sky, near Moscow, a pump of this kind was erected in 1784, which raised a hogshead of water in a 
 minute to a height of 74 feet, and through a pipe 760 feet in length. Eytelwein enters very minutely 
 into calculations of the effect of such a machine under different circumstances ; and the results of the 
 theory, as well as of experiment, recommend it for common use, instead of forcing pumps of a more 
 complicated and expensive construction. The water-tight joint presents the only difficulty : the pipe 
 may form either a cylindrical, a conical, or a plain spiral, and it appears to he uncertain which is the 
 most advantageous ; the vertical pipe should be nearly of the same dimensions as the spiral pipe. 
 
 The Screw of Archimedes , or the Water-Snail , and the Water-screw. The screw of Archimedes con- 
 sists, either of a pipe wound spirally round a cylinder, or of one or more spiral excavations, formed by 
 means of spiral projections from an internal cylinder, covered by an external coating, so as to be water- 
 tight. But if the coating is detached, so as to remain at rest w'hile the spirals revolve, the machine is 
 called a water-screw. Eytelwein observes, that the screw of Archimedes should always be so placed, 
 as to fill exactly one-half of a convolution in each turn ; and that when the orifice remains constantly 
 immersed, the effect is very much diminished. When the height of the water is so variable as to render 
 this precaution impossible, Mr. Eytelwein prefers the water-screw ; although, in this instrument, one- 
 third of the water runs back, and it is easily clogged by accidental impurities. The screw of Archime- 
 des is generally placed so as to form an angle of between 45° and 60° with the horizon, but the open 
 water-screw at an angle of 30° only: for great heights, the spiral pump is preferable to either. 
 
 Belidor's pressure engine, moved hy water. — Fig. 
 
 3150: A conveys the descending column of water 
 from its source to the three-way cock F ; to one of 
 the openings of which it is united. This cock is con- 
 nected, at another opening, to the horizontal cylinder 
 C, whose axis coincides with that of a smaller one D. 
 
 Both cylinders are of the same length ; and their pis- 
 tons are attached to a common rod, as represented in 
 the figure. Two valves are placed in the ascend- 
 ing pipe B — one below, the other above its junction 
 with the cylinder D. The horizontal pipe H con- 
 nects B and D with the third opening of the cock. 
 
 By turning the plug of this cock, a communication 
 is opened alternately between each cylinder and the 
 water in A. Thus when the water rushes into C it 
 drives the piston before it to the extremity of the 
 cylinder, and consequently the water that was pre- 
 
PUMPS. 
 
 537 
 
 viously in D is forced up the ascending pipe B ; then the communication between A and C is cut off, 
 (by turning the cock,) and that between A and D is opened, when the pistons are moved back towards F 
 by the pressure of the column against the smaller piston — the water previously in C escaping through 
 an opening shown in front of the cock and runs to waste, while that which enters D is necessarily forced 
 up B at the next stroke of the pistons. The cock was opened and closed by levers, connected to the 
 middle of the piston-rod, and was thus worked by the machine itself. By the air-chamber the discharge 
 from B is rendered continuous. 
 
 Suppose the water A has a perpendicular fall of thirty-four or thirty-five feet, and it was required 
 to raise a portion of it to an elevation of seventy feet above F ; it will be apparent that if both pistons 
 were of the same diameter, such an object could not be accomplished by this machine — for both cylin- 
 ders would virtually be but one — and so would the pistons ; and the pressure of the column on both 
 sides of the latter would be equal. A column of water thirty -five feet high presses on the base that 
 sustains it with a force of 15 pounds on every superficial inch; and one of seventy feet high, with a 
 force of 30 pounds on every inch ; hence, without regarding the friction to be overcome, which arises 
 from the rubbing of the pistons, from the passage of the water through the pipes, and from the 
 necessary apparatus to render the machine self-acting, it is obvious in the case supposed that the area 
 of the piston in C must be more than double that in D, or no water could be discharged through B. 
 Thus in all cases, the relative proportion between the area of the pistons, or diameter of the cylinders, 
 must be determined by the difference between the perpendicular height of the two columns. When the 
 descending one passes through a perpendicular space, greatly exceeding that of the ascending one, then 
 the cylinder of the latter may be larger than that of the former ; a smaller quantity of water in this 
 case raising a larger one. It, however, descends like a small weight at the long end of a lever, through 
 a greater space. 
 
 That the force which a running stream acquires may be made to drive a portion of the liquid above 
 the source whence it flows, is obvious from several operations in nature. 
 
 The hydraulic ram raises water on this principle : a quantity of the liquid is set in motion through an 
 inclined tube, and its escape from tire lower orifice is made suddenly to cease, when the momentum of 
 the moving mass drives up a portion of its own volume to an elevation much higher than that from 
 which it descended. 
 
 The first person who is known to have raised water by a ram, designed for the purpose, was Mr. 
 'Whitehurst, a watchmaker of Derby, in England. He erected a machine similar to the one represented 
 in Fig. 3151, in 1772. 
 
 A represents the spring or reservoir, the surface of the water in which was of about the same level 
 as the bottom of the cistern B. The main pipe from A to the cock at the end of 0, was nearly six 
 hundred feet in length, and one and a half inch bore. The cock was sixteen feet below A, and fur- 
 nished water for the kitchen offices, &c. When it was opened the liquid column in A C was put in 
 motion, and acquired a velocity due to a fall of sixteen feet ; and as soon as the cock was shut, the mo- 
 mentum of this long column opened the valve, upon which part of the water rushed into the air-vessel 
 and up the vertical pipe into B. This effect took place every time the cock was used, and as water 
 was drawn from it at short intervals for household purposes, “ from morning till night — all the days in 
 the year,” an abundance was raised into B, without any exertion or expense. 
 
 The Belier hydraulique of Montgolfier was invented in 1796. Although it is on the principle of the 
 one just described, its invention is believed to have been entirely independent of the latter. 
 
538 
 
 PUMPS, STEAM. 
 
 Fig. 3152 represents a simple form of Montgolfier’s ram. The motive column descends from a spring 
 or brook A, through the pipe B, near the end of which an air chamber D, and rising main F, are attached 
 to it as shown in the figure. At the extreme end of B the orifice is opened and closed by a valve E, 
 .nstead of the cock in Fig. 3151. This valve opens downwards, and may either be a spherical one, as 
 in Fig. 3152, or a common spindle one, as in Fig. 3153. It is the play of this valve that renders the 
 machine self-acting. To accomplish this, the valve is made of. or loaded with, such a weight as just to 
 open when the water B is at rest; i. e., it must be so heavy as to overcome the pressure against its 
 under side when closed, as represented in Fig. 3153. Now suppose this valve open as in Fig. 3152, the 
 water flowing through B soon acquires an additional force that carries up the valve against its seat ; 
 then, as in shutting the cock of Whitehurst’s machine, a portion of the water will enter and rise in F, 
 the valve of the air-chamber preventing its return. When this has taken place the water in B has been 
 brought to rest, and as in that state its pressure is insufficient to sustain the weight of the valve, E 
 opens, (descends ;) the water in B is agaiu put in motion, and again it closes E as before, when another 
 portion is driven into the air-vessel and pipe F ; and thus the operation is continued, as long as the 
 spring affords a sufficient supply and the apparatus remains in order. 
 
 The surface of the water in the spring or source should always be kept at the same elevation, so that 
 its pressure against the valve E may always be uniform — otherwise the weight of E would have to be 
 altered as the surface of the spring rose and fell. 
 
 This beautiful machine may be adapted to numerous locations in every country, and is coming much 
 into use in the agricultural districts of this country. When the perpendicular fall from the spring to 
 tlie valve E is but a few feet, and the water is required to be raised to a considerable height through F, 
 then, the length of the ram or pipe B must be increased, and to such an extent that the water in it is 
 not forced back into the spring when E closes, which will always be the case if B is not of sufficient 
 length. 
 
 If a ran. of large dimensions, and made like Fig. 3152, be used to raise water to a great elevation, 
 it would be subject to an inconvenience that would soon destroy the beneficial effect of the air-chamber 
 If air be subjected to great pressure in contact with water, it in time becomes incorporated with or 
 absorbed by the latter. This sometimes occurs in water-rams ; as these, when used, are incessantly at 
 work both day and night. To remedy this, Montgolfier ingeniously adapted a very small valve (opening 
 inwards) to the pipe beneath the air-chamber, and which was opened and shut by the ordinary action 
 of the machine. Thus, when the flow of the water through B is suddenly stopped by the valve E, a 
 partial vacuum is produced immediately below the air-chamber by the recoil of the water, at which 
 instant the small valve opens and a portion of air enters and supplies that which the water absorbs. 
 Sometimes this snifting-valve, as it has been named, is adapted to another chamber immediately below 
 that which forms the reservoir of air, as at B in Eig. 3153. In small rams a sufficient supply is found 
 to enter at the valve E. 
 
 Although air-chambers or vessels are not, strictly speaking, constituent elements of water-rams, they 
 ate indispensable to the permanent operation of these machines. Without them, the pipes would soon 
 oe ruptured by the violent concussion consequent on the sudden stoppage of the efflux of the motive 
 column. See Embank' s Hydraulics. 
 
 PUMPS, STEAM. Pig. 3154 and 3155 represent an independent steam pumping machine, pa- 
 tented in April, 1849, by Worthington - & Baker, of the city of New York, and which is undoubtedly- 
 the best pump in use for heavy purposes. 
 
 The general principle involved in its construction is the combination of a pump with the steam-cylin- 
 ler that drives it by direct action, without the intervention of a crank fly-wheel or any other device 
 for producing rotary motion. The steam-cylinder S is in all respects similar to that of an ordinary 
 
 aigh-pressure engine, with the parts as usually constructed for the admission and emission of the steam. 
 The rod of the piston which traverses in this cylinder is prolonged and attached to the plunger P of a 
 double-acting pump. 
 
 The arm A is fastened to the middle of the piston-rod, and strikes the tappits or nuts on the valve- 
 
PUMPS, STEAM. 
 
 539 
 
 rod at eacli end of the stroke, in order to change the position of the steam-valve and admit steam to 
 alternate sides of the piston. The necessary reciprocating motion of the pump-plunger is thus produced 
 in a very simple way, with the least possible amount of friction and loss of power. 
 
 The brief space afforded in a notice of this description, will only allow of a glance at the mechanical 
 peculiarities of this machine, designed to overcome the difficulties incident to the direct application ol 
 steam, without availing of the controlling power of the crank for regulating the stroke nor of the ec- 
 centric for producing the proper motion of the steam-valve. At low speed, more especially, the obvious 
 tendency of the motion is to bring the steam-valve directly over the ports, and exclude the steam from 
 either end of the cylinder. The patentees have obviated this serious difficulty in a manner at once sim- 
 ple and effective. By a peculiar arrangement of the water passages in the pump, the resistance is re- 
 duced or relieved at or near the end of the stroke, and thus a momentum is suddenly generated amply 
 sufficient to throw the valve wide open. A modification of the ordinary slide-valve, which the patentees 
 denominate a B valve, is shown in the drawing, and serves to admit the steam in the proper direction, 
 without resorting to levers for changing the motion. 
 
 The pump shown at C, called the double-acting plunger pump , consists of a plunger or plug P, work 
 ing through a ring R, which may be made adjustable, if necessary. 
 
 The course of the water, as indicated by the arrows, is through a set of valves resting upon seats 
 that radiate from a common centre, and covered in by the cap A, Fig. 3154, which is held firmly in its 
 place by the single bolt B. As all these valves are thus accessible at a moment’s warning, a great 
 source of danger from delay in relieving them from impediments is avoided. 
 
 This pump is in general use on board of steamboats, and in connection with stationary boilers, both 
 on account of its value as an independent feed-pump, and also as a means of safety against accidents, 
 having been found of great use as a bilge pump, and also as a fire engine. 
 
 This pump has also been employed for water supply in the city of Savannah, Ga., and Cambridge, 
 Mass. The duty at the latter place almost comes up to that of the best Cornish Engines. The 
 engines consist each of two cylinders on the Wolf plan, with condensers. The cylinders are concentric, 
 the smaller being interior, and the larger exterior ; the piston of the latter being annular with two rods 
 The whole machine is compact and economical, both in first cost and in working. 
 
 PUMPS. Carrett’s Steam Pump. Figs. 3156 and 4157 represent two views of the pump, construct- 
 ed to deliver ten gallons per minute at a height of 130 feet, the steam power being derived from a 
 two-horse portable high-pressure boiler, complete in itself, and weighing under 6 cwt. 
 
540 
 
 PUMPS, STEAM. 
 
 Fig. 3157 is a front elevation of the pump and actuating steam-cylinder, and Fig. 3156 is a corre- 
 sponding side elevation or view, at right angles to the first figure. The steam-cylinder A is inverted 
 upon the horizontal plate B, which is bolted to the top of the two-standards C, forming the framing 
 of the machine. These standards spring from the chest D, which answers as the base of the whole, and 
 contains the influx and efflux vessels for the water. The branch E conveys the steam to the slide-valve 
 chest F, which is arranged in the simplest manner, the slide being worked direct from the eccentric G, 
 on the crank-shaft H. The crank-shaft is carried in two bearings in the cross-piece of the side stand- 
 ards, and is connected to the piston-rod I, of the steam-cylinder, by passing the cranked-portion, fitted 
 with a steel slide J, through the horizontal slotted cross-head K, of the piston-rod. The latter is pro- 
 longed below the cross-head, for the purpose of carrying 
 the water-plunger L, which is bored out and entered 
 upon the rod, and secured by set screws. When the 
 engine is not required for pumping, the plunges is dis- 
 connected by slackening these screws, and the piston- 
 rod then works loose inside the plunger as a guide, the 
 the power of the engine being then devoted to driving 
 other machinery by a belt on the fly-wheel, or by con- 
 necting the crank-shaft with the machinery to be driven, 
 by means of a link or universal joint, which, in the 
 figure, is supposed to be broken away. The whole of 
 the pump-work is shown by sectioned dotted lines in the 
 base chest. The pump cylinder or barrel is at M, 
 in the centre, and the passage N, at- the top, forms the 
 communication with the vertical influx water-passage 
 0, governed by the conical lift-valve P. The bottom 
 of this passage opens into an air-vessel Q, which, with 
 the corresponding vessel for the discharge on the oppo- 
 site side, forms the chief feature of improvement in the 
 arrangement. The water is taken in by a pipe attached 
 by a union joint at R, to the base chest. The discharge 
 is by the opposite port, fitted with the lift-valve S, which 
 opens into the top passage T, communicating with the 
 top of the discharge air-vessel U, which has a discharge 
 pipe attached at V. 
 
 It is this neat combination of air-vessels, with the in- 
 flux and efflux passages, which enables the pump to be 
 worked at an effective speed without injury to the differ- 
 ent movements, whilst a constant and regular delivery 
 is completely secured. Without a provision of this na- 
 ture the barrel of the common pump is only partially 
 filled at each stroke, and the ram is consequently driven 
 against the surface of the water with a serious shock at 
 each down stroke. On the other hand, in Mr. Carrett’s 
 
 pump, the lower valve, at each ascent of the plunger, 
 
 drains its water supply from the bottom of the induction 
 air-vessel ; which again is fully replenished by the suc- 
 tional power from the reservoir. When the plunger 
 descends, the water in the barrel is driven through the 
 upper valve into the discharge air-chamber, and makes 
 its escape thence in a “ continuous stream,” under the 
 pressure of the contained air. Thus, the pump has a noiseless and perfectly smooth action, with a uni- 
 form delivery. 
 
 Our plate shows the old slotted cross-head movement as adopted for returning the plunger at each 
 termination of its stroke, and for this purpose, as there is no great strain on the working parts, this sim- 
 ple plan has met with an apt application. For powers of pumps from three horses upwards, a connect- 
 ing-rod and vertical slide movement is substituted, and this of course is a much more suitable arrange- 
 
 ment where the engine is intended occasionally to exert its power through the crank-shaft. 
 
 The slotted frame is not, however, a mere aperture, as in the original plan adopted in steam-engines. 
 A thin metal plate is bolted on each side, so as to provide projecting edges as guide flanges for the slide- 
 block, and to retain the lubricating oil on the surfaces where it is wanted. 
 
 Pumps like the preceding, with a fly-wheel, are better suited to constant work than to the variable 
 duty of feed-pump to a boiler. They must be run with sufficient velocity that the impetus of the fly- 
 wheel may carry the valve sufficiently far to open the ports. This difficulty, as has already been ex- 
 plained, has been obviated in the Worthington pump, by relieving the pressure on the pump piston 
 near the conclusion of the stroke. In Garrison’s pump, also a direct action pump, this throw is effected 
 in the steam chest. 
 
 The motion is somewhat similar to the working motion of a planing machine, fig. 3080. The roa 
 x is the valve, and the weight r consists of a small piston working in a cylinder open at the upper end 
 to the steam pressure, the other end connected with the exhaust. In this way the pressure of the 
 steam is made to serve for the weight ; other direct engines have been constructed in which the valve 
 is worked by another sma. 1 engine. 
 
 3157. 
 
PUMPING-ENGINE. 
 
 541 
 
 PUMPING-ENGINE, erected at the new Dry Dock, Brooklyn Navy Yard, New York. The pumping- 
 engine of the new Dry Dock, at the United States Naval Station, New York, is of the largest class, 
 and possesses many interesting features. It was built at Kemble’s West Point Foundry, and affords 
 additional proof of the capability of that establishment to execute the most massive work in the highest 
 degree of perfection. 
 
 There are but very few specimens of large pumping- engines to be found in the United States, those 
 if the government dry docks at Norfolk and Boston being the most important. These, however, are 
 of somewhat antiquated construction, and possess no remarkable qualities of excellence. The new 
 dock at New York being the largest in the country, and at the most extensive naval station, it was 
 deemed important that the machinery for exhausting it should be of the most perfect kind, and of great 
 power and capacity also, as but a very inconsiderable amount of aid is afforded by the recession ol 
 the tide. 
 
 The “duty” required of the engine was to raise 610,000 cubic feet of sea-water in three hours, dis- 
 .ributed through different heights, as follows : 
 
 110.000 cubic feet of water raised through an average height of 21- feet. 
 
 j.25,000 “ “ 71 “ 
 
 115.000 “ “ 12J “ 
 
542 
 
 PUMPING-ENGINE. 
 
 110.000 cubic feet of water raised through an average height of 174 feet. 
 
 110,000 “ “ 22 | “ 
 
 40,000 “ “ 26 
 
 610.000 
 
 The commission appointed to devise a plan, unanimously adopted that shown in the accompanying 
 figures, a brief description of which is here given. 
 
 The pumps are two in number, of the kind denominated “lifting-pumps,” each 63 inches in diameter 
 of cylinder and 8 feet length of stroke. The suction-pipes (also 63 inches in diameter) are extended tc 
 the bottom of the well, and terminate in suitable rose-pieces, with ample apertures in the sides for the 
 
 4028. — Elevation and Section of the Pumps. 
 
 ? 1 1 M f , ..7 s ... V 
 
 admission of the water. By this arrangement a staunch support is furnished for the insistent weight 
 of the upper works of the pumps and the engine above. Each suction-pipe is furnished with a capa- 
 cious branch-piece, (63 inches diameter,) forming a connection with an air (or vacuum) chamber, sit- 
 uated centrally between the pumps, and extending up to the bottom of the upper (or engine) bed-plate. 
 This air-chamber, in addition to the support received from the branch pipes, is upheld by a hollow 
 cylindrical pillar resting on the bottom of the well. A continuation of this pillar is carried through the 
 centre of the air-chamber to the under side of the lower (or pump) bed-plate. 
 
 The pump-cylinders, suction and branch pipes, the air-chamber and its support, are r>f cast-iron, 
 
PUMPING-ENGINE. 
 
 543 
 
 flanged and ribbed, as represented in the figures, the pump-cylinders lieing lined with composition 
 metal. 
 
 The mouths of the pumps are placed at the level of mean low water, in a chamber formed of cast- 
 iron, 8 feet wide, 13 feet high, and 30 feet long, — the bottom of the chamber forming a support to the 
 heads of the pump-cylinders, as well as a bed-plate for the air-pump and condenser of the engine : its 
 sides, strongly ribbed, support the engine bed-plate with the superstructure, and the top is itself a part 
 of the engine bed-plate. A culvert from the bay leads up to one of the sides of this chamber, and 
 serves as a conduit for the water delivered from the pumps. Twelve of the panels of the side of the 
 
 chamber adjoining the conduit are open, and furnished with flap-valves of vulcanized India-rubber, 
 opening outwardly to prevent the rising tide from flowing into the chamber. Four cast-iron girders of 
 J. section, 32 inches deep, are placed transversely across the well, directly underneath the bottom of 
 this chamber, and are held down to the masonry by suitable bolts. 
 
 Ihe arrangement of the pump-valves is of somewhat novel character, a suction-valve being placed 
 near the bottom of each suction-pipe, in addition to the usual one near the bottom of the pump-cham- 
 bers. Each of these valves is provided with suitable chests and bonnets, and is composed of vulcanized 
 ndia-rubber, with the usual metal guard above. A disk of India-rubber, cut to the proper shape, with 
 punctures along its diameter, is slipped over standards, tapped into the valve-seat, and secured by 
 washers and the nuts of the guard; the India-rubber alone, from its flexibility, forming the hinge. 
 
 due valve-seats are of composition metal, their faces being indented in such ? manner as to require 
 
0 44 
 
 PUMPING ENGINE. 
 
 two sets of valves to eaeli chest, and are divided into numerous apertures by narrow but deep bars, 
 crossing each other at right angles. This cross-barring forms a support for the flexible material of the 
 valve, and obviates all the difficulty to be apprehended from the tendency of the valve to collapse on 
 being loaded. A perfectly tight and quiet-working valve is the consequence of this arrangement. 
 
 The pump-rods are double, and passing through stuffing-boxes in the floating covers with which the 
 pumps are provided, take hold of cross-heads working in slides below the engine bed-plate. From 
 these cross-heads, double connecting-rods extend directly to the beam of the engine. 
 
 The engine is a double-acting condensing one, of 50 inches diameter of cylinder, and 12 feet length 
 of stroke, with an independent adjustable expansion-geer, so arranged, that as the load upon the engine 
 is increased by the lowering of the water in the dock, a proportionate increased amount of steam is ad- 
 mitted into the cylinder. 
 
 The working beam is of cast-iron, 31 feet long between the “ end centres,” and 4 feet deep at the 
 “ main centre,” strongly flanged and bossed. The piston-rod is attached to the beam by a parallel 
 motion; the main-pump and air-pump rods are connected to it by double rods and links, the air-pump 
 cross-head working in slides attached to the columns of the engine-frame. The balance-wheel is of 
 cast-iron, 25 feet in diameter, a cross section of its rim having an area of about 80 square inches. Its 
 arms (eight in number,) unite in a centre case, having compartments to receive their tapered ends. 
 
 The condenser is formed from a portion of the air or vacuum chamber before described, a partition 
 being placed in that portion of it which extends above the engine bed-plate. The air-pump stands level 
 with the condenser. The air-pump rod and bucket, foot-valve and seat, are of composition metal. The 
 length of stroke is 42 inches, the diameter of the cylinder 44 inches. The interior of the cylinder is 
 lined with composition metaL 
 
 The piston, cylinder-cover, and steam chests, side-pipes, valves, and valve-geering, are all nearly 
 identical with those used in the best specimens of American steamboat engines. The boilers are three in 
 number, 2G feet long, and of 7 feet diameter in the waist, built on the ‘ ‘ single return drop flue ” plan. 
 They are fed by the direct action steam-pumps of Worthington and Baker of New York. 
 
 PUMPING ENGINES. For the water supply of cities the Cornish Engine (q. v.) for this purpose 
 affords the highest rate of duty. We know of no others that are remarkable either in construction or 
 duty, except the one at Cambridge, Mass., already spoken of, and one at Hartford, Conn. The pecu- 
 liarity of the latter consists in the arrangement of the piston in the pump cylinders : there are two 
 pistons in each cylinder, the piston-rod of the lower passing through that of the upper, and so arranged 
 in their alternate movements, that the flow of water is nearly continuous. They are actuated by cams, 
 driven by a vertical steam engine, working very expansively. 
 
 PUMP, LEEGIIWATER STEAM. — Drainage of the Haarlem Lake , Holland. In order to ascertain 
 the most approved method, and at the same time the most economical manner, of draining this lake, the 
 Dutch government appointed a commission of engineers to report upon the best means, and to examine 
 the various plans of drainage adopted in England. After examining a great variety of schemes and 
 proposals, it was determined to adopt the plan submitted by Mr. Joseph Gibbs and Mr. Arthur Dean. 
 It is proposed to have three engines of the same power, and three sets of pumps. The first of these 
 engines is now in operation, and is shown in Figs. 3158 to 3161. 
 
 Description of the engines. The Leeghwater Engine, as shown in the figures, has two steam cylinders 
 A and C, one within the other, united to the same bottom X ; but the inner one is not attached at the 
 top, a clear space of 1^- inch existing between it and the cover, which serves for both cylinders. The 
 large cylinder A, is 144'37 inches diameter, and 1^- inch thick; and C, the small cylinder, 8D25 inches 
 diameter, and If inch thick ; both are truly bored out, and the small cylinder is also turned on its outer 
 circumference. B is a steam-jacket for the large cylinder, cast in 13 segments — which is again enve- 
 loped in a wooden casing l , having 4 inches of peat ashes between them. 
 
 Pistons. — The small cylinder C is fitted with a plain piston of 5474-81 square inches area, and tho 
 large cylinder A is occupied by an annular piston of 10323-36 square inches area. The areas of the 
 two cylinders, after deducting 472'8 square inches for the thickness of small cylinder, are as 1 to 2-85. 
 The internal and external packings of the pistons consist of hard cast-iron segments at bottom, with 
 gasket above, pressed down by glands, also in segments; the qpen spaces in the pistons cc are filled 
 with cast-iron plates, and the tops of the pistons have movable cast-iron covers. 
 
 Cap or cross-head. — The pistons are connected to the great cap or cross-head G, by the main piston- 
 rod Y, of 12 inches diameter, and by four small rods y, of 4£ inches diameter, (Fig. 3158.) 
 The great cap G has a circular body 9 feet 6 inches diameter, divided into eight compartments, which 
 can be filled with cast-iron weights ; from its centre a guide-spindle z, passes through a stuffing-box 
 placed in the centre of a great beam of timber 2 feet square, which passes across the engine-house, and 
 is secured to its walls ; there are two other guide-rods b, which pass through stuffing-boxes in the arms 
 of the great cap G, and are secured to the upper and lower spring beams. 
 
 Plungers. — Suspended from the arms of the great cap are two 9-inch plunger-poles F, working ir. 
 plunger-cases D ; attached to D are two valve-nozzles d'\ connected with stand-pipes d\ by two branch 
 pipes d" ; the valve-nozzles are connected with each other and a hydrostatic equilibrium valve-nozzle 
 O, from the bottom of which a branch piece is connected with the stand-pipes d by the pipes d"". The 
 exterior surfaces of the plunger-cases D are turned truly, so as to allow the rings e e to slide up and 
 down freely ; the rings are suspended from the great cross-head by rods v, and are furnished with cross- 
 bearings, on which the jaws of the two air-pump balance-beams E rest : the inner ends of these balance- 
 beams move in a perfectly vertical line, and the outer ends are furnished with rollers working between 
 guides, to allow for the variation of the beams during the up or down stroke. 
 
 Air-pump. — From the centre of the air-pump balances, the two air-pump plunger pistons n are sus- 
 pended, (Fig. 3159;) diameter of plunger pistons 40 inches, stroke 5 feet; the two air-pumps N are 
 united by a branch piece with the bottom of the condenser M. The condenser has an intermittent in 
 
PUMP, LEEGHWATER STEAM. 
 
 545 
 
 jeclion by a valve 8 inches diameter, and a constant injection by another valve of 3 inches diameter, 
 it is the condenser cistern. 
 
 Pipes and valves . — L is the steam-pipe (2 feet diameter) from the boilers ; in it is placed a double 
 beat governor-valve of 16 inches diameter. 
 
 P, the induction-valve, 10 inches diameter and nozzle. 
 
 Q, Equilibrium-valve, 20 do. do. do. 
 
 S, Eduction-valve, 26 do. do. do 
 
 q , Equilibrium steam-pipe. 
 
 The induction and equilibrium nozzles are each connected to a separate port cast in the cylinder’s bot- 
 tom. The eduction nozzle is connected by a pipe M, 34 inches diameter, to the branch-pipe M of the 
 condenser. The pipe M is also connected to the bottom of the cylinder, in which a port is cast, which 
 communicates with the space under the annular piston; by this arrangement a constant vacuum is 
 maintained beneath that piston. 
 
 The hand-geer is connected to the weigh-post K, and the plug-rod is worked by a lever and shaft T, 
 the outer end of which is slotted and worked by a pin on the sliding-ring e. 
 
 Pumps.— The engine works eleven pumps of 63 inches diameter ; each pump is furnished with a 
 cast-iron balance-beam H, (Fig. 3158,) which radiates from the centre of the piston-rod ; the inner and 
 outer arms are of equal lengths from the centre gudgeon. The inner ends of the balance-beams are 
 furnished with cast-iron rollers, working against a plate, fitted with guides for each roller, which is 
 screwed up against the under side of the great cap ; each beam is connected to the cap by two slotted 
 bridles, to insure simultaneous upward motion during the up-stroke of the engine. From the outer end 
 of the balance-beam the pump piston is suspended by wrought-iron rods, 3 inches diameter and 16 feet 
 long, and an additional length of 14 feet of patent chain cable attached to the pump piston. Fio\ 3160 
 shows a section of one of the pumps, and Fig. 3161 an elevation of the piston. A, working barrel, 63 
 inches diameter ; B, windbore and clack piece ; C, the piston or bucket ; D, bottom valve and seat 
 Vol. II. — 35 
 
546 
 
 PUMP, LEEGHWATER STEAM. 
 
 The pump piston C is of a peculiar construction ; it is composed of a wrought-iron centre-piece, 1 inch 
 thick ; firmly bolted to this piece are two double elbow frames of cast-iron, called “ the cradles ;” the 
 elbows are faced with gun-metal plates ; the cradles serve to support two wrought-iron semi-elliptic 
 valves cc, which occupy the whole area of the pump when they fall out, and constitute in fact the pis- 
 ton. These valves are edged with wood, having a piece of leather on the upper side secured by a 
 wrought-iron gland ; the valves are hung to the centre-piece at about 3 inches from their lower edges, 
 so that when they open during the down stroke, any dirt or sand which has lodged on the bottom may 
 fall through. Attached to the centre-piece are two plates of cast-iron, which serve as ballast to sink 
 the piston ; these ends are cast with a jaw, in which pieces of wood are secured to prevent friction 
 against the sides of the pump, and to give steadiness to the piston. These pistons require a weight of 
 1'4 lb. per square inch of the area of the pump to sink them with the velocity required upon the down 
 stroke. The pump pistons of the Leeghwater are not furnished with guides, as shown in Figs. 3160 and 
 3161 , and work very well without them : but the pistons for the pumps of the Cruquius and Van Lyn- 
 den engines (now constructing for the drainage of the lake) will have guides, in consequence of the 
 diameter of the pumps being increased to 73 inches. 
 
 Ptimp valves. — The bottom valves have cast-iron seats secured to the windbore, the valve beats are 
 of wood, and the valves are simply plates of wrought-iron, 1 inch thick ; the valves are not hung on 
 tired joints, but are each fixed to a bar, the ends of which are entered in cast-iron slot-pieces, allowing 
 a rise of 1 J inch, so that the valve can rise altogether from its beat, and give a large water passage all 
 round. 
 
 Power of engines. — The steam and pump pistons both perform a stroke of 10 feet in length: each 
 pump by calculation should deliver 6'02 tons of water per stroke, or 66'22 tons for the eleven pumps; 
 but by actual admeasurement of the quantity delivered, it is found to be 63 tons. The loss might be 
 reduced, but probably at the expense of increased friction. 
 
 The engine-house is a massive circular tower, concentric to the cylinders ; on its walls are placed the 
 eleven pump balances radiating from its centre. The eleven pump balances are so placed as in no way 
 to disturb the equilibrium of the great cap of the engine, under which the inner ends of all the balances 
 are concentrated. If any of the pumps require repairs, the opposite pairs can be easily detached, with- 
 out causing more than a trivial delay to the working of the engine. 
 
 The astion of the engine is very simple ; the steam being admitted into the small cylinder, the whole 
 of the dead weight and pump-balance beams attached to the great cross-head are elevated with it, and 
 the steam being cut off at such portion of the stroke as may be required, the remainder is effected by 
 the momentum acquired by the dead weight and the pressure of the expanding steam upon the small 
 piston, (the pump pistons at the same time make their down stroke ;) at the end of the up stroke a 
 pause of one or two seconds is requisite, to enable the valves of the pump pistons to fall out, so that 
 upon the down stroke of the steam piston they may take their load of water without shock. During 
 this time it is necessary to sustain the great cross-head and its load of dead weight at the point to which 
 it was elevated by the up stroke, as otherwise it would fall back until the expanded steam under the 
 small piston was compressed to a density equal to the pressure per square inch of the load lifted, or 
 would cause a very violent shock upon the pump-valves by suddenly throwing them out against the 
 sides of the pumps. To avoid these evils the hydraulic apparatus D F was devised. 
 
 Hydraulic apparatus. — When the engine makes its up stroke, the plunger-poles F (which form part 
 of the dead weight) are lifted, and the water from the stand-pipes and reservoirs d' flows through the 
 valves d", and follows up the plunger-poles as fast as they are elevated. At the end of the stroke the 
 spherical valves instantly close, and the dead weight is suspended exactly at the point at which it had 
 arrived — and, of course, if the valves are tight, could be maintained there for any given period ; in con- 
 sequence of all strain being thus removed, there is no pressure to close the valves of the pump pistons 
 beyond their own weight ; therefore, they fall out without the slightest shock. To make the down 
 stroke, the equilibrium steam-valve Q, and the hydraulic valve 0 are opened simultaneously : the water 
 from beneath the plungers escapes to the stand-pipes and reservoirs by the pipes d"", and the steam 
 from the small cylinder passes by the pipe q, round to the upper side of the small and annular pistons, 
 puts the pressure on the small piston in equilibrium, and presses upon the annular piston, (beneath 
 which a constant vacuum is maintained,) in aid of the dead weight now resting upon the inner ends 
 of the pump balances : by the united effort, the pump pistons are elevated and the water dis- 
 charged. Before the next stroke is made, the eduction-valve is opened and a vacuum formed over both 
 pistons. 
 
 So well does the hydraulic apparatus just described effect the object for which it was designed, that 
 the Haarlem-mer Meer Commissioners have decided to use only eight pumps, but of 73 inches diameter, 
 for the other engines ; the chief reason for the adoption of the 63-inch pumps for the Leeghwater Engine 
 having been the fear of the shocks to which such large pump pistons are ordinarily liable. 
 
 Boilers. — The Leeghwater Engine is furnished with five cylindrical boilers, each 30 feet long and 6 
 feet diameter, with a central fire-tube, 4 feet diameter : a return flue passes under the boilers to the 
 front, and then splits along the sides. Over the boilers is a steam chamber, 4 feet 6 inches in diameter 
 and 42 feet in length, communicating with each boiler; from thence a steam-pipe, of 2 feet diameter, 
 conducts the steam to the engine. The steam space in the chamber, boilers, 'and pipe is nearly 1 320 
 cubic feet, and as the engine draws its supplies from such an immense reservoir of steam, no “ primage’’ 
 takes place, and a very uniform pressure upon the piston is obtained until the induction-valve closes 
 These boilers have produced steam enough to work the engine to the net power of 400 horses. The 
 Oruquius and Van Lynden Engines will have boilers capable of working to 500 horses’ power if re- 
 quired. 
 
 The drainage.— Prior to the construction of the engine-house, &c., an earthen dam of a semicircular 
 form was thrown out into the lake, to inclose about 1^ acres; after the water was pumped out from 
 
PUMP, LEEGHWATER STEAM. 
 
 547 
 
 within the dam, a strong piled foundation was made, and the masonry commenced at the depth of 21 
 feet below the surface of the lake : a small steam-engine was erected to evacuate the water from the 
 dam. When the Leeghwater was completed, the commissioners determined to test its merits fully 
 before deciding on the construction of the other engines upon the same model ; and as they had the 
 means of evacuating the water within the dam to any level required, the Leeghwater could be tried 
 and worked continuously under any circumstances, precisely similar to those which will occur during 
 the drainage of the lake, if, instead of discharging the water from the pumps into the upper canal, it 
 was allowed to fall back again to the level from whence it was derived. 
 
 The average depth of the lake is 13 feet below the general level of the surface water of the canal 
 and water-courses conducting to the sea-sluices ; when the communications between those waters and 
 ♦lie lake are closed, the engine will at first have only the head of water caused by the discharge from 
 the pumps, and the friction of the machinery, to overcome ; in this state, all the filling plates or ballast 
 of the great cap and pistons will be taken out, and counter-balances added to the pump balance-beams 
 “ out of doors,” so as to take up as much of the dead weight attached to the great cap as may not be 
 required for working the engine : as the lift becomes greater, the dead weight “ in-doors” will be gradu- 
 ally added. In this manner the engine was worked for a considerable time, to get all the parts in good 
 working order. A sub-committee of the commission conducted a series of experiments, and satisfied 
 themselves that the Leeghwater will perform a duty of 75 million pounds, lifted one foot high, by the 
 consumption of 94 lbs. of good Welsh coal, whilst exerting a net effective force of 350 horses’ power. 
 With a lift of 13 feet, the engine easily worked the eleven pumps simultaneously; the net load of 
 water lifted being 81'7 tons, and the discharge 63 tons, t«er stroke. 
 
 When the bed of the lake is cultivated, the surface of the water in the drains will be kept at IS 
 inches below the general level of the bottom ; but in time of winter floods, the waters of the upper 
 level of the country will be raised above their ordinary height : in which case, to keep the bed of the 
 lake drained to the regulated height, the lift and head may be increased to 17 feet. To test the power 
 of the engine under these circumstances, (and without regard to the consumption of fuel,) the whole of 
 the 11 pumps were worked simultaneously, and the extraordinary quantity of 109 tons net of water 
 was raised per stroke to the height of 10 feet; but, in practice, it will be advisable to work a less num- 
 ber of pumps, and increase the number of strokes per minute. 
 
 After numerous and severe trials of the engine, the commissioners were satisfied that it is capable of 
 performing its work under the most difficult circumstances that can arise ; and immediately determined 
 on having two more engines constructed, of equal size, and on the same model — the only material alter- 
 ation being in the arrangement of the pumps ; the number being reduced to 8 for each engine, but of 
 73 inches diameter, placed in pairs opposite each other, and the ends of the balance-beams projecting 
 over the great cap of the engine, (instead of under as in the Leeghwater,) to which they will be con- 
 nected by stout wrought-iron straps. The boilers also will be increased in number, and in power nearly 
 100 horses. All the feed-water will be filtered before passing into the boilers. 
 
 Advantages of two cylinders. — Many persons imagine that the engines are constructed witli two cylin 
 ders to obtain a greater expansion of the steam than would be attainable in one cylinder ; but such is 
 not the case, as no greater economy of steam can be obtained by the use of two cylinders than by one, 
 although greater steadiness of motion for rotatory engines, and less strain upon the pit-work of a mine- 
 pumping engine, may result from the use of two cylinders. In the Haarlem engines two cylinders are 
 used, because if one cylinder only were employed it would sometimes be necessary to use a dead weight 
 of 125 tons to overcome the resistance of the water load and friction of the engine and pumps ; such a 
 mass of iron or other heavy material would be unmanageable, and no alteration in the force of the en- 
 gine could be effected but by taking from or adding to the dead weight, which would be a source of 
 great difficulty and inconvenience, when the varying character of the load, during the drainage of the 
 lake, is considered ; particularly as at times the water will be charged with so much foreign matter as 
 greatly to add to the friction of the pumps. By the system adopted the maximum dead weight ele- 
 vated by the small piston will seldom exceed 85 tons, the additional power required being derived 
 from the pressure of the return steam, at the down stroke, on the annular piston ; by varying the ex- 
 pansion and pressure of the steam in the small cylinder, the engineman can add to, or diminish the 
 pressure upon the annular piston, so as to meet any case of variable resistance without the inconveni- 
 ence and delay attending an alteration of the dead weight ; the load is therefore under perfect com- 
 mand at all times. 
 
 Quantity of water. — The area of the Haarlem Lake is 45,230 acres, the estimated contents to be 
 pumped out about 800 million tons ; but should the quantity be increased by any unforeseen cause 
 even to 1000 million tons, the whole amount could be evacuated by the three engines in about 400 
 days. 
 
 The bed of the lake when drained must be always kept dry by machinery, and observations continued 
 during 91 years show that the greatest quantity of rain which fell upon the area of the lake in that 
 period would give 36 million tons as the maximum quantity of water to be elevated by the engines in 
 one month ; to perform this work would require a force of 1084 horses’ power to be exerted during that 
 period ; the average annual drainage is estimated at 54 million tons. 
 
 The cost of the Leeghwater, buildings and machinery, was £36,000 ; of this amount about £15,000 are 
 due to the buildings and certain contingencies. For the foundations 1400 piles were driven to the depth 
 of 40 feet into a bed of hard sand, and a strong platform laid thereon at the depth of 21 feet below the 
 surface of the lake ; upon this platform, at the distance of 22 feet from the engine-house, a strong wall 
 pierced with arches was constructed, and at 7 feet from the coping a stout floor of oak was laid between 
 the wall and the engine-house ; the pumps rest upon the platform beneath and opposite the arches, and 
 their heads come through the floor alluded to, and stand about 3 feet above its level : into the canal 
 thus formed between the engine-house and the outer wall, the water from the pumps is discharged and 
 
548 
 
 PUNCH, REVOLVING SPRING. 
 
 flows off on either side of the boiler-house, through sluice-gates, into the canals conducting to the sea 
 sluices. 
 
 The great cost of the buildings, for whatever description of machinery might have been employed, 
 rendered it an object of considerable importance to lessen this expense by concentrating the power tc 
 drain the lake in three engines ; in addition to which a considerable saving in the wages of enginemen, 
 stokers, and others is effected, as these large engines require very little more attendance than an ordi- 
 nary mine engine ; this is an important feature in the economy of the charge for the permanent drain- 
 age of the “Polder,” which will be formed by the bed of the lake. 
 
 The average consumption of the ordinary land-draining engines applied to scoop-wheels and Archi- 
 median screws, may be taken at 15 lbs. of coal per net horse-power per hour; this quantity will be 
 greatly reduced if the horses power of the engines be calculated by the pressure of the steam on the 
 pistons, and not by the net delivery of the water ; in a case where the water delivered by a large 
 steam-engine working a scoop wheel, was measured during eight hours, the engine was found to exert 
 a net force of 73 horses’ power during the first hour, with a consumption of 15 lbs. of coals per net horse- 
 power ; as the lift increased the power diminished, and the consumption of fuel increased, until at the 
 eighth hour it was found that the engine only exerted a net force of 33 horses’ power, and consumed 24 
 lbs. of coal per net horse-power per hour. The consumption of fuel by the Leeghwater is 2-J lbs. of coals 
 per horse-power per hour when working with a net effective power of 350 horses. 
 
 No new principle has been developed in the Leeghwater, but important facts have been demonstrated 
 which must have an immense influence on the progress of agricultural hydraulic engineering : it has 
 proved that witli proper attention to well-known principles, steam-engines of the very largest class (the 
 Leeghwater is believed to be the largest and most powerful land engine ever constructed) may be em- 
 ployed to raise great bodies of water from low lifts for the drainage or irrigation of low lands with as 
 great an economy of fuel as was hitherto generally supposed to be confined to the elevation of com- 
 paratively small quantities of water to great heights. To the Haarlem-mer Meer Commissioners be- 
 longs the merit of having ventured to carry out this bold experiment, and they will reap their reward 
 by an economy of at least £100,000 over the cost of draining the lake by the ordinary system of steam- 
 engines and hydraulic machinery employed to drain land ; and of upwards of £170.000 and three 
 years time over the cost of draining the lake by the windmill system hitherto generally employed in 
 Holland. 
 
 The Leeghwater is named in honor of a celebrated Dutch engineer, who, from his great success in 
 draining numerous lakes in North Holland, was popularly known by the name of “ Leeghwater,” or “ the 
 drier-up of water,” and with him the first proposal to drain the lake originated in 1623. 
 
 The engines and pumps were manufactured at the establishment of Messrs. Harvey Co., of Hayle, 
 and Messrs. Fox & Co., of Perran, Cornwall. 
 
 PUNCH, REVOLVING- SPRING. Invented by S. Merrick, of Springfield, Mass., and patented 
 February 28th, 1848. 
 
 This tool is designed for punching leather and other like material, and contains four punches of vary 
 ing size, either of which can be instantly brought into use. 
 
 In the drawings, Fig. 3162 denotes a side elevation. 
 
 Fig. 3163 an end view of the cylinder E, and the series of rotating punches FFFF, showing the 
 right-angular shoulders b, on the punches. 
 
 In said Figures A denotes the bed-lever of the punches ; B, the punch-lever, or that which supiports 
 or carries the series of rotating punches FFFF, which are sustained and revolve between spring-jaws 
 D D. I is the bed or blank of copper, in conjunction with which the lower punch acts during the opera- 
 
 3162. 3103. 
 
 tion of punching ; E is the cylinder to which the several punches are fastened : right-angular notches 
 are made in the lower side of the spring-jaws D, which notches are made to fit the projections or 
 right-angular shoulders b, made on the sides of the punches; their object is to prevent the lower 
 punch from being moved forward towards the extremity of the lever A during the operation of 
 punching. Each punch of the series is fitted with like shoulders. The notches are made in cam pro- 
 jections, formed respectively on the spring-jaws. For the purpose of effectually discharging the little 
 circles or cylinders of material separated from any article by the cutters, and which pass through the 
 cutters and into the interior of the cvlinder E, a cone is arranged with respect to the discharging 
 mouths of the punches, so that, after the pieces of leather have passed out of the punches they are 
 forced against the cone, and by it directed laterally and out of the space. Without some such con 
 trivance, the space is very liable so become filled or choked by the pieces which are cut away by the 
 punches. 
 
 The remaining parts of the punch will be obvious without further description. 
 
PUNCHING MACHINE, STEAM. 
 
 549 
 
 PUNCHING MACHINE, STEAM. — By M. Cave, Paris. Fig. 3164, elevation. Fig. 3165, end 
 view. Fi°\ 3166, nlan. Fig. 8167, sectional plan of punching-frame. Fig. 3168, section of cutter 
 adapted to machine for cutting plate. Fig. 3169, elevation of the same. Fig. 3170, plan. Fig. 3171, 
 section showing the mode of keying the punch. 
 
 Literal References. 
 
 * team-cylinder. 
 
 b, piston and cross-head h’. 
 
 c, slide-valVe, opening alternately the steam-port 
 c' and exhaust- port c", worked by rod d. 
 
 d shde-rod. 
 
 e, steam-pipe. 
 
 f, punching-lever, connected to the piston by the 
 links/' and cross-head b' working in frames /". 
 
 g, punching cylinder, connected to lever f by the 
 links g. 
 
 h, frame for carrying punching machinery. 
 
 j, lever fixed to the rod d for stopping the machine 
 by the pins/; it is worked by the handle j " 
 and counterbalance/”. 
 
 k, connecting-rod. 
 
 l, crank and shaft. 
 
550 
 
 PUNCHING AND PLATE-CUTTING MACHINE. 
 
 m, fly-wheel. 
 
 n, punch, 
 
 o, dies. 
 x>, stop. 
 
 I q, plate being punched. 
 
 r, foundations. 
 
 s, aperture through which the iron plate punched 
 I out falls. 
 
 PUNCHING AND PLATE-CUTTING MACHINE. By Messrs. Nasmyth, Gaskell d' Co., Man 
 Chester . Fig. 3172, front elevation. Fig. 3173, side elevation. 
 
 3172. 
 
 Literal References. 
 
 а, tight and loose riggers. 
 
 б, fly-wheel. 
 
 c, spur-wheel and pinion. 
 
 d, frame for carrying machinery. 
 
 e, shaft and eccentric for raising and depressing 
 slide. 
 
 3173. 
 
 ft slide, the upper end having a steel cutter g, and 
 the lower end the punches h. 
 
 g, steel cutters. 
 
 h, punches. 
 
 i, die-frame. 
 
 /, stop for preventing the plate from rising. 
 k, travelling table for carrying plate to be punched. 
 
 l, rods, levers, and spindle for advancing the trav 
 elling table by means of tappet m, on spur-wheel 
 
 m, tappet on spur-wheel. 
 
 n, rack-bar attached to brackets o of travelling 
 table. 
 
 o, brackets fixed to table. 
 
 p, carriage for supporting spindle. 
 
PUNCHING AND SHEARING MACHINE. 
 
 551 
 
 PUNCHING AND SHEARING MACHINE. By Cairo & Co., Greenock. These figures repre 
 sent the form and general arrangement of a machine of great importance and utility in the manufacture 
 of steam-engine boilers. The present example is distinguished for its mechanical elegance of design, 
 simplicity of construction, compactness and strength. Although the machine occupies only a very in- 
 considerable space on the floor of the factory, it is capable of punching and shearing plates of one inch 
 in thickness. 
 
 Fig. .3174: is a general side elevation of the machine. 
 
 Fig. BUS is a front elevation, looking upon that face of the machine which is adapted to the opera- 
 tion of shearing. 
 
 Fig. 3176 is a corresponding elevation of the opposite end at which the operation of punching is per- 
 formed. 
 
 Fig. 3177 shows the form of the main-shaft and section of the slides. 
 
 General description . — The framing consists of a single massive casting A A, having strong brackets 
 B C and D E formed upon it at opposite sides. In the pieces B and D recesses are formed for the re- 
 ception of the bushes of the shaft N, and of the slides b b, to which the shearing cutter and punch are 
 attached respectively. The bushes of the shaft N are adjusted to the proper degree of tightness by the 
 
 3174 . 
 
 cotters dd; and the extremities a a of the shaft, close to these bearings, are formed eccentrically, as 
 shown in Fig. 3177. These eccentric ends are inserted into the slides bb, and work in oblong bushes of 
 such a form as to allow the eccentrics to move freely in a lateral direction, while the full amount of 
 their vertical motion is transferred to the slides. These bushes are retained in their places by thin 
 wrought-iron covers c c. 
 
 The slides move vertically between the parallel dovetail guides e e, fixed by screws tapped into the 
 projecting pieces B and D, which are carefully dressed to allow the slides to move freely but without 
 play upon them. On the shearing slide is fixed a steel cutter/, acting in contact with the stationary 
 cutter inserted into the table C ; the cutting edges form an acute angle with each other, so that during 
 the process of shearing, the action is rendered gradual. The opposite slide carries the punching-tool r/, 
 which is held in its socket by a cotter h ; the small hole i, immediately over it, is for the convenience 
 of driving the punch out of the socket when required. The die-holder is attached to the table E by two 
 screws tapped into the table, and thus admits of being changed at pleasure. 
 
 The shaft N derives its motion from the large bevel mortise-wheel M M, keyed upon it between th< 
 cheeks of the frame. This^pheel geers with, and is put in motion by, the pinion L, or the low _ r enu 
 of the vertical shaft J, which is carried in a step supported in a bracket cast on the inside of one of the 
 
552 
 
 RAG AND WASTE PICKER. 
 
 cheeks; the upper end revolves in an independent hearing attached to any convenient beam. The 
 power is transmitted to this shaft from the driving-shaft F, by means of the two bevel-wheels Cf and 
 H. On the upper end of the same shaft J is keyed the fly-wheel K, for equalizing the motion of the 
 machine under the irregular strains to which it is subject. 
 
 Action of the machine . — Motion being communicated to the eccentric-shaft N, the slides will be made 
 to travel vertically through spaces corresponding to the eccentricity of the parts a a, thereby working 
 the shears and punch alternately ; the eccentricity of the two extremities being formed on opposite 
 sides of the shaft, so that while the punch is descending, the cutter of the shears will be ascending, and 
 vice versa. The plates under operation are shifted by hand, upon tables of wood erected at the proper 
 levels, and usually witlf guides fixed upon them for insuring accuracy in the operation of cutting. 
 
 Literal References. 
 
 L A, the frame of the machine. 
 
 B, hollow bracket for the shearing-slide. 
 
 C, the fixed table for the same. 
 
 D, hollow bracket for the punching-slide. 
 
 E, the table upon which the hollow die is set. 
 
 h a, eccentric ends of the shaft N. 
 
 L b, the shearing and punching slides. 
 
 c c, covers fixed upon the slides over the ends of the 
 eccentrics a a. 
 
 dd, cotters for adjusting the adjusting bearings of 
 the shaft N. 
 
 ce, dovetail guiding pieces between which the 
 slides move. 
 
 f the shearing-cutter. 
 
 ( 7 , the punching-tool. 
 
 /i, a cotter for fixing the punch in its socket. 
 
 i, an oblong hole over the socket of the punch lor 
 driving it out when required. 
 
 F, the shaft by which the power is led to the ma- 
 chine. 
 
 G, a bevel-wheel on the horizontal driving-shaft, 
 geering with 
 
 H, a bevel-wheel on the vertical driving-shaft J. 
 
 K, the fly-wheel for regulating the motion of the 
 machine. 
 
 L, a bevel-pinion on the vertical shaft J, geering 
 with 
 
 M, a large bevel mortise-wheel fixed on 
 
 FT, the main eccentric-shaft. 
 
 PYROMETER. An instrument for measuring the degrees of heat. The term pyrometer is generally 
 understood to denote either an instrument intended to measure higher temperatures than can be 
 measured by the ordinary thermometer, or an instrument for comparing the expansions of different 
 metals. 
 
 Various contrivances have been employed for the above purposes. Musschenbroek, the original 
 inventor of the pyrometer, adopted the following method : A prismatic rod (about six inches long) of 
 
 the metal under trial being attached at one extremity to an immovable obstacle, and heated by lamps, 
 the other end is necessarily pushed forward ; and this being fastened to the end of a rack playing into 
 a pinion, communicates a revolving motion to an axle to which a train of wheel-work is attached, 
 vdiereby the minutest expansion of the heated bar is rendered sensible, and measured by an index on a 
 dial. The principle of this apparatus is sufficiently simple; but the uncertainty attending the motion 
 of so many loosely connected wheels and pinions must have rendered its indications of little value ; and 
 the method is liable to a still more serious objection, namely, that the temperature communicated to 
 the bar by the lamps is entirely unknown. Desaguliers, and afterwards Ellicott, made several improve- 
 ments in the construction of the instrument, tending to give it a more equable motion and to increase its 
 delicacy. Graham substituted a micrometer screw for the wheels and levers that had formerly been 
 employed ; and on this principle Mr. Smeaton contrived an ingenious apparatus, which is described in 
 the Phil. Trans., vol. xlviii. 
 
 RAG AND WASTE PICKER — By C. G. Sargent. It has always been a desideratum, and hith- 
 erto unaccomplished in any practical degree, for the manufacturer to be able to reduce waste yarn and 
 poor or worn fabrics to their original condition of fibre, and capable of being again worked into cloth. 
 The above machine accomplishes this object, being capable of reducing 150 pounds of waste woollen 
 yarns, so that they may be easily carded and spun anew. It was invented after trials of several modes, 
 and after much consideration, by Mr. Charles G. Sargent, of Lowell, and he is now constructing them 
 for most of the woollen-mills in that section of the country. The cost of one whose cylinders are 12 
 inches long, with full rights to use it, is about §300. 
 
 The machine and its action may be described by reference to Fig. 3178, which represents a longitu- 
 dinal section of it. The frame being represented at A A A, <fcc., the casings at B B B, <Src., D being a 
 shaft put in motion by some force, and from which motion is communicated to all moving parts. The 
 yarn, cloth, or other material required to be picked, is spread upon a feeding apron E, which has a slow 
 motion towards the roll F, which has a motion indicated by the arrows, and being fluted or toothed 
 draws in the material between itself and the iron shell G, and passes it forward to the roll F', which is 
 similar to F, and has a quicker angular motion than it, thereby insuring that it may take all that is 
 presented by the roll F, and at the same time tending to draw the threads or fibres to a position at 
 right angles to its axis, the rolls F and F' being so supported that they can rise and fall from and to- 
 wards the shell G, according as there may be large or small pieces between them and the shell. 
 
 The material is thrust out from between the roil F' and the shell G, towards the first picking cylinder 
 H. This cylinder is formed by adding to a plain cylindrical pulley strips of metal, about 1 inch by | 
 inch, and of the same length as the face of the pulley. Parallel to its axis and upon the outer surfaces 
 of these strips, are secured plates somewhat wider than the strips, having fine teeth cut upon one of 
 their edges, and set in such a manner that the points of the teeth will fc*; somewhat further from the 
 centre of the pulley than the other edge, and also projecting forward in the direction of die motion ol 
 
RAILROADS. 
 
 553 
 
 the pulley, and overlapping the strips to which they are attached. This cylinder being so placed that 
 the teeth of the serrated plates will, when the cylinder is in motion, barely clear the shell G, when the 
 material is projected from between the roll F' and the shell G the part so projected will be combed ana 
 torn to shreds, while the twist of the yarn will be taken out by the rapid action of the senated plates, 
 while large and long pieces will be prevented from being passed through by being held between the 
 rolls and the shells. The material is taken from the cylinder H by the brush I, which revolves more 
 rapidly, and at the same time is assisted by the fan R, which also keeps the brush clean. By the cur- 
 rent of air produced by the fan and brush the material, now partially picked, is blown upon the second 
 feeding apron J, which has a slow movement indicated by the arrows, and is prevented from leaving 
 this apron by the cylinder K, which revolves slowly, being carried by the aprorf This cylinder is made 
 by covering a slight frame with wire cloth, thus allowing the air to pass through it and retain the ma- 
 terial upon the apron, forming a lap. 
 
 3178. 
 
 The material now passes under the small roll L, which is a plain cylinder, and for the purpose j 
 eading it to the second pair of feeding-rolls M M', the cylinder 0, the brush P, and fan R, each ol 
 which acts respectively the same as the rolls F F', the cylinder II, brush I, and fan R, except that the 
 teeth of the cylinder O are finer than those of H, and that the material is now blown out of the machine 
 picked, and again ready for the card. 
 
 RAILROADS. The limits and scope of this work forbid enlarging upon the history of railroads, or 
 tracing their development from the rude tram-ways of the German mines, to their present highly ad- 
 vanced state of perfection. A great deal has been written on this branch of the subject, easy of access, 
 and the reader is referred to Wood, Breese, Dempsey, and others on railroads. We have to do in this 
 place with railroads in the light of machines, and as such describe them as they are ; the principles 
 upon which they are projected and located, constructed and worked. 
 
 Railroads are roads upon which the carriages travel on iron rails, to which they are confined by pro- 
 jections on their wheels, called flanges. 
 
 The principles which govern in the location of a railroad are the same as those of a common road ; 
 the motor in general use on the former, however, renders necessary a more rigorous observance of these 
 principles. 
 
 The resistance to motion on roads is occasioned : 1st. By the want of uniformity in the surface of the 
 road ; the weight of the load having to be lifted over the projecting points and out of the hollows or 
 ruts, thus diminishing the effective load which the power may draw to such as it can lift. 
 
 2d. The want of strength of the road-bed itself let its surface be as even or uniform as it may, adds 
 another impediment to the movement of a load over it, with the additional disadvantage that while the 
 power is endeavoring to lift the load from a cavity or hollow, the fulcrum, which in the first case w’as 
 supposed to be rigid and fixed, is in the latter yielding and variable, subjecting the power to the con- 
 stant effort of lifting instead of simply drawing. To these causes of resistance are to be added, 
 
 3d. The grade of the road, or the quantity by which it differs from a level. This resistance is due to 
 the force of gravity, and unlike the others may be determined from the well-known laws of mechanics, 
 whilst the former are determinable entirely by experiment on the road in question or a similar one. 
 
 Friction of the axles and resistance of the air. — This, it is true, is a fourth cause of resistance to mo- 
 tion on roads, but its consideration may be neglected for the present, as its effects are constant, and in 
 dependent of the imperfections of the road. 
 
 The first cause of resistance above enumerated, want of uniformity or evenness of the road surface, is 
 attempted to be overcome in the railroad by substituting for the uneven gravel or pavement a hard and 
 smooth iron surface, or the rail. The second cause of resistance is diminished by a system of construe 
 tions whose aim is to afford the iron rail a permanent and unyielding support. 
 
 The whole art of railroad building , then, consists in producing for the carriage to roll on, a hard, smooth 
 surface, upon an unyielding foundation or road-bed — in appearance a very simple matter— in reality a 
 ’ ery difficult one. 
 
 To exhibit at a glance the value of a smooth surface — From experiments made upon the best turn- 
 
554 
 
 RAILROADS. 
 
 pike road in England, and probably in the world, the following was found to be the force of traction, or 
 the weight in pounds which, hanging over a pulley, would draw one ton on a level part of the road — 
 the road-bed as firm as most railways : 
 
 On a well-made smooth pavement 33 lbs. 
 
 On a broken stone surface (macadamized) over an old flint road 65 “ 
 
 On a gravel road 147 “ 
 
 On a macadamized road, on a rough permanent foundation 46 “ 
 
 On a macadamized surface, on a foundation of cement and gravel 46 “ 
 
 Average, 67 lbs. 
 
 On a good edge railroad, the force of traction on a level is usually taken 
 for one ton at 8 “ 
 
 or a horse will draw from five to eighteen times as much on a good railroad as upon the best turn- 
 pike roads in use, and this is due to the smoothness of the surface alone. 
 
 This illustrates the extent of the first cause of resistance to motion on roads. 
 
 For the second, it may be sufficient to mention a circumstance within the writer’s experience. A lo- 
 comotive engine, built at Lowell, drew, on trial, on the Lowell and Boston Railroad, up a grade rising 
 30 feet per mile, the same load which it barely drew on a level part of the inferior railroad upon which 
 it was subsequently worked. The surfaces in the two cases were the same, wrought-iron ; but the one 
 road-bed and rail was firm, and the other yielding. 
 
 The engine which could draw, say 300 tons gross, on a grade rising 30 feet per mile, the rail per- 
 fectly firm, would, in the same condition of rail, draw 475 tons on a level. This illustrates the value of 
 a firm and unyielding road surface. 
 
 Location. — In the location of a railroad, the termini are in most cases fixed, and the engineer, having 
 in consideration the nature and amount of the traffic anticipated on the road, must so adjust its align- 
 ment, both vertical and horizontal, as with the least expenditure in first cost and in subsequent working, 
 to produce the greatest effect — in this case, the greatest return on the capital invested in the building 
 maintenance, and working of the road. 
 
 The perfection of a railroad would seem to be a straight line and a level, and yet there may be con- 
 trolling circumstances which would render a level road not desirable ; such as a very heavy trade of 
 coal, lumber, ores, &c., in one direction : in fact, the trade may be such as to render the weight of the 
 empty return wagons alone the data for limiting the steepness of the grade ; and again, when the trade 
 is well balanced, it would be desirable to have the acclivities and declivities balanced, and the profile 
 to be an undulating grade, providing a level road could not be found. In general, however, let wdiat 
 $ill be the best grade in view of the weight of traffic or other circumstances, it is rarely that these con- 
 ditions can be rigorously obtained, save at a cost which will defeat its own object; for it is undeniable 
 that a good road may cost too much. For instance, a heavy trade in one direction with no return of 
 freight would seem to call for a uniform descending grade, or a grade undulating between level and 
 descending; and yet to obtain these advantages ridges may require tunnelling, and expensive works 
 encountered, to pay the cost of which would require tolls on the traffic for which the road was built, 
 tending to throw the article out of the market in competition with other sources of supply. Between 
 these limits of maximum acclivity and level the engineer is to make his selection, keeping always in 
 view the conditions which he is aiming to fulfil, avoiding a hill here, cutting through a ridge there, again 
 tunnelling in preference to adding to the length of line or to the curvature, or the reverse, increasing the 
 length of the road very materially in some cases in order to avoid encountering heavy expenditures, &.C. 
 After he has made a careful reconnoissauce of the country between the termini, and an instrumental 
 examination of such lines of route as appear to his judgment the best calculated to fulfil the conditions 
 sought, it wffil usually be found that one of two things exist : either the true route is indicated beyond 
 all doubt by the features of the country, in which case it remains but to improve the line within nar- 
 rower limits, or else several lines offer, either of which may, to the unassisted judgment, appear to fulfil 
 all the required conditions. In the latter case, after improving each line in detail in reference to bal- 
 ancing the material to be used, that is to say, where possible, making the cuttings furnish the material 
 for the filling ; reducing the amount of curvature as much as possible ; selecting the proper crossings of 
 rivers, swamps, ridges, Ac. ; examining foundations of all kinds ; ascertaining the fitness of the material 
 to form banks ; examining quarries, timber, price of labor and materials, and, in general, ascertain- 
 ing the capabilities of the country on each route : the several routes are then compared in view of their 
 first cost, maintenance, and working, and not unlikely a new element will appear of the varying amounts 
 of the local or way business to be anticipated and provided for. 
 
 A treatise on railroad engineering would of itself require more space than can be allotted to the whole 
 subject of railroads in a dictionary. This will account for the suppression of much of the detail which 
 would be sought for in a complete treatise on railroad building. We must omit, therefore, the consid- 
 eration of the preliminary operations of surveying and levelling, as well as the form and character of the 
 respective works which make up the construction of a railroad ; such as bridges, culverts, tunnels, founda- 
 tions, Ac., and which, in their principles of construction, are common to many branches of internal im- 
 provement.* 
 
 In preparing the estimates of the several lines, plans in detail are made of all the mechanical struc- 
 tures from which their cost is deduced : profiles are made exhibiting the grades of the road together with 
 
 * These are subjects of but little interest to the general reader, and the student in the science of engineering should look 
 Slsewliere than in a dictionary, however comprehensive, for the principles of his profession. 
 
 Ir. the first volume of this Dictionary reference is frequently made to “railway engineering;” but the subject is, we 
 conceive, foreign to the character of this work, which is a dictionary of “ machines,” showing the principles of their construc- 
 tion and working, or the “engineering of machinery” simply. — [Ed. 2d. VoL.j 
 
RAILROADS. 
 
 the cuts and fills, and tables exhibiting the cubical contents of the various sections of the work, as also 
 the horizontal alignment, showing the relative amounts of straight line and curves, and the character 
 of the latter. The cost of construction having thus been obtained of the various lines, they are equated 
 for their respective amounts of ascents, descent, and curvature, the ruling grade, or the grade which 
 limits the effective power of the engines to be used, determined, and the lines of routes brought under 
 one general view for comparison. 
 
 Equating for grades . — The result of experiments carefully conducted gives as the resistance to motion 
 of one ton, moving on a well-built level railroad, about 8-J- pounds, or the weight which hanging freely 
 over a pulley will overcome the friction of one ton. This resistance to motion is a constant fraction of 
 the weight moved, and is its ^- T th part. This is the friction of the load. If now the plane be elevated 
 from a level to a rise of -^J-j-th its length, according to well-known mechanical laws 1 pound will on this 
 plane sustain 264 pounds, (See Inclined Plane and Mechanical Powers,) or 84 pounds will sustain 
 one ton ; and the fraction representing a rise of 20 feet in a mile ; it follows that on this grade the 
 effect of gravity is equal to that of friction, and in order to produce motion up this grade, twice the 
 power must be applied that would be required were it on a level ; and as it is a well-known mechani- 
 cal law that the same amount of power is expended in raising a weight through a given height, what- 
 ever may be the angle of the plane upon which the motion is effected, it follows that for every 20 feet 
 in height that we ascend on a railroad, we expend an amount of power equivalent to the transport of 
 that weight over one mile of level ; and this holds true whatever the grade may be. Equating for 
 grades with a view to a comparison of lines, then, consists in adding to the measured distance one mile for 
 each and every twenty feet of ascent on the respective routes. 
 
 Equating for curves . — Direct motions on levels or inclines are affected less by disturbing causes than 
 motion in curves ; for in addition to the irregularities growing out of the imperfections of the curved 
 track and the varying elements of the curved motion in practice, is to be added all the disturbing causes 
 which exist in the first case. This has, as yet, prevented that rigorous solution of the latter problem, 
 which is to be desired, and which is essential to a true comparison, a priori , of the cost of movement on 
 curved roads. It is as yet entirely an empirical formula deduced from a few experiments, but has been 
 used for the purpose of comparison of routes by distinguished engineers, and is the best we can offer 
 with our present knowledge of the subject 
 
 We find by the experiments referred to above, that a curve of 400 feet radius doubles the resistance. 
 In propelling a train, then, through an entire circumference of such a curve, we expend twice the power 
 that would be consumed in travelling an equal distance in a right line. 
 
 Taking, then, the analogy afforded by motion on ascents as compared with levels as a guide, and we 
 conclude that the same power would be expended in turning through an entire circle, whatever may be 
 its radius, (this, of course, must be understood as confined to certain limits ;). hence, for every circle of 
 860 degrees, we must add for the expenditure of power on a right line of the same length, the circum- 
 ference of a circle described with the radius of double resistance, found by experiment as above to be 
 400 feet ; this will be half a mile. Equating for curves consists, then, in adding to the measured distance 
 one half mile for each and every three hundred and sixty degrees of curvature on the respective routes. 
 
 Having explained the principles which govern in reducing the several routes under comparison to a 
 aniform standard in respect to their distance, curvature, and grades, we will introduce an example from 
 actual practice illustrative of the every-day operations of comparing routes preliminary to a selection of 
 one for construction. 
 
 The road in question was- to connect two points some ninety miles apart, for which seven routes were 
 examined, nowhere distant from each other more than seven miles, and the nature of the country and 
 the anticipated traffic such as to reduce the question of a choice of routes to that of economy of con- 
 struction, maintenance, and working — independently of any local advantages which one route might 
 possess. 
 
 The cost of repairs per mile per year of roads as nearly similarly circumstanced as possible, and with 
 a given traffic, having been obtained from their official returns, as also the cost of working, the former 
 amounting to $600 per mile, was multiplied by the measured distances of the lines, and the latter, 
 amounting to $150 per mile, was multiplied by the distances resulting from equating the lines for curva- 
 ture and grades as above described. 
 
 A capital which at 6 per cent, will furnish the first amount is shown in the sixth column of the table 
 below; the capital to furnish the second is shown in the seventh column. 
 
 Table exhibiting the measured and equated Distances on the Various Lines surveyed for Railroad , with 
 the estimated Cost of each, including Graduation, Masonry, Wooden Bridging, and Railway, with the 
 Capital requisite at 6 per cent, to f urnish an annual sum adequate to maintain and work each line. 
 
 Description of Lines. 
 
 No. 
 
 Measured 
 distances in 
 miles and 
 decimals. 
 
 Equated 
 distances in 
 miles and 
 decimals. 
 
 Estimated 
 cost of con- 
 struction. 
 
 Equivalent 
 capital to main- 
 tain. 
 
 Equivalent 
 capital to work. 
 
 Grand totals. 
 
 Upper line 
 
 1 
 
 92-63 
 
 160-13 
 
 $1,127,471 
 
 $926,375,00 
 
 $2,001,636,25 
 
 $4,055,482,56 
 
 Lower line 
 
 o 
 
 91-06 
 
 157-22 
 
 1,067,816 
 
 910,632,00 
 
 1,965,256,25 
 
 3,943,705,17 
 
 I/>wer line B 
 
 3 
 
 89-64 
 
 157'40 
 
 1,076,042 
 
 896,416,00 
 
 1,967,527,50 
 
 3,939,985,66 
 
 Lower line C 
 
 4 
 
 90-07 
 
 156 - 60 
 
 1,087,689 
 
 900,766,00 
 
 1,957,543,75 
 
 3,945,999,02 
 
 Lower line D 
 
 5 
 
 90-24 
 
 155-97 
 
 1,073,518 
 
 902,478,00 
 
 1,949,741,25 
 
 3,925,737,52 
 
 | Lower line E 
 
 6 
 
 91'65 
 
 159"55 
 
 1,124,509 
 
 916,596,00 
 
 1,994,416,25 
 
 4,035,522,00 
 
 Upper line B 
 
 7 
 
 93-51 
 
 160-79 
 
 1,129,097 
 
 935,116,00 
 
 2,009,911,25 
 
 4,074,124,74 
 
556 
 
 RAILROADS. 
 
 Judging the lines by these tests, we find that No 1, or the upper line , stands Gth in order of direct 
 ness, Gth in point of value derive 1 from present actual outlay, Gth in order of working, and of course Gth 
 in the aggregate of them all. 
 
 No 2. or the lower line, is 
 
 No. 3 stands 
 
 No. 4 stands 
 
 No. 5 stands 
 
 No. G stands 
 
 f 2d 
 J 4th 
 1 2d 
 [4th 
 
 f 2d 
 J 2d 
 
 | 1st 
 [1st 
 
 f 5th 
 
 J Oth 
 
 1 5th 
 [5th 
 
 No. 7 
 
 In order of directness. 
 
 In value derived per actual present outlay. 
 In order of working. 
 
 In the aggregate of all these considerations. 
 
 In order of directness. 
 
 In value derived per actual present outlay. 
 In order of working, and 
 In aggregate of all these. 
 
 In order of directness. 
 
 In actual present outlay. 
 
 In order of working. 
 
 In aggregate of all these. 
 
 In order of directness. 
 
 In actual present outlay. 
 
 In cost of working, and 
 In aggregate of them all. 
 
 In order of directness. 
 
 In order of actual present outlay. 
 
 In cost of working. 
 
 In aggregate of alL 
 
 Is the inferior one in every respect, standing 
 last in all the comparisons. 
 
 Simplifying the matter as far as possible, we have four routes, No. 2, 3, 4 and 5, differing from each 
 ether, in the extremes of the first respect, rather less than two per cent., and in the latter about per 
 cent. 
 
 There seems no substantial reason at this stage of the case, founded upon such minute differences, for 
 preferring one hue over another, and we must therefore consider what improvements each is susceptible 
 cf, when it comes to be definitely staked off for construction. 
 
 It is very rare, however, that so small differences appear in the comparison of several routes, but it 
 is introduced here as an example in actual practice, and showing a very proper method of comparison. 
 
 The route having been determined on, we proceed to the construction. 
 
 Excavation and embankment . — Let ABC, Tig. 3179, represent a profile or longitudinal section of a 
 portion of the line over which the railroad is to pass, and abed the level at which the road is to be formed, 
 
 3179 . 
 
 constituting what is called the grade line. All those parts of the section above the line abed will re- 
 quire to be cut down, and are called cuttings ; and those portions below this line will require to be filled 
 up, and are designated as embankment, or fillings. 
 
 Where a trifling variation in the general inclination of the line or of the grades is not of great im- 
 portance, it is very advisable that the line should be so laid out that the quantity of earth, or material 
 required for making the embankments, should not be greater than what is to be obtained from the ex- 
 cavations. There is, however, an exception to this in cuttings or embankments of great lengths. Cases 
 may occur where the distance between the cutting and embankment is such, that the expense of con- 
 
 3180. 
 
 veying the earth from one part of the line to another is greater than the increased expense of borrowing 
 material alongside the line of railway, or near the embankment, for the purpose of forming the embank- 
 ment ; and of depositing the earth from the cut, which ought to have formed the embankment, upon 
 waste ground alongside such cut, in spoil bank. These are, however, cases to be judged of by the en- 
 gineer of the work, and are entirely questions of comparative expense between the one mode and the 
 other. 
 
RAILROADS. 
 
 557 
 
 Width of the railway. — Fig. 3180 is a cross section of an excavation or cutting, and Fig. 3181 a cross 
 bection of an embankment ; ab being the original surface of the ground, and gh the bottom level or ex 
 treme depth of the excavation. The first question to determine is the width at the bottom level, as by 
 this the whole of the operations are guided ; and this depends upon two considerations : first, the width 
 between the rails ; and next, the width between the two lines, if the railway is intended to be a double 
 line. 
 
 3181. 
 
 
 N— . . 
 
 7. 
 
 \ 
 
 ■ A 
 
 
 s 
 
 A 
 
 . A 
 
 
 f. 
 
 + 
 
 \ 
 
 1 
 
 
 5 
 
 i 
 
 
 
 6 
 
 i 
 
 ft 
 
 
 
 A 
 
 Width between the rails. — The first public railway, of any extent, which was executed, was the Stock- 
 ton and Darlington Railway. The width between the rails of that railway was made four feet eight inch- 
 es and a half, taking the Ivillingworth Colliery Railway as a standard. The Liverpool and Manchester 
 Railway, constructed by the same engineer, was formed of the same width ; and it was then made a 
 standing order of the legislature in England that, in all public lines of railway, the width, between the 
 lTiils, should be four feet eight inches and a half. In 1836 this standing order was suspended, and there 
 is now, or was until lately', no standard of width whatever. 
 
 The following are the principal gages in use, ranging from 4 feet 6 inches to 7 feet : "Mo. 1. — 1 
 feet 6 inches, originally laid down in Scotland. No. 2. — 4 feet 84 inches, the gage in most general use. 
 No. 3. — of 5 feet, formerly adopted for the 
 Eastern Counties and Blackwall lines, in Eng- 
 land. No. 4. — of 5 feet 6 inches, used in Scot- 
 land. No. 5. — The New York and Erie Rail- 
 road of 6 feet. No. 6. — The Irish gage of 6 
 feet 2 inches ; and No. 7, the Great "Western of 
 7 feet gage, in England. 
 
 The confusion actually resulting, and to be an- 
 ticipated by this want of uniformity in the con 
 
 etruction of the “ arterial circulation,” so to speak, of Great Britain, led to the appointment by government 
 of a commission to inquire into and report upon the most advantageous width to be adopted in the future 
 construction of railroads in that country. The subject was examined with all the minuteness which its 
 importance called for; every evidence was received from the friends of the several widths which it was 
 in their power to furnish, and the result was a report from the commission in favor of the “ narrow 
 gage,” or four feet eight and a half inches between the rails as affording all the advantages claimed for 
 the “broad gage,” and at a diminished expense. It. is now the standard gage in that country, but in 
 our own the matter is still left to the caprice of individuals or companies. 
 
 We shall, then, assume the width between the rails to be four feet eight inches and a half. The 
 breadth of the bearing part of the rails cannot vary much ; about two inches and a half seem to be the 
 width agreed upon by almost, if not all, engineers. The width between the outside of the rails will, 
 therefore, be five feet one inch and a half; or five feet one inch if the breadth of the rail itself be two 
 inches and a quarter. 
 
 Width between the two tracks. — The next consideration is the width between the tracks of the railway. 
 Upon the Liverpool and Manchester, the width was made the same as that between the rails, viz, four 
 feet eight inches and a half. On the London and Birmingham, and the Grand Junction Railways, the 
 width is six feet; and less than this is not considered advisable, and is the width almost universally 
 adopted in this country. 
 
 Width on the outside of the rails. — The next question to determine is the width required on the out- 
 side of the rails, or between the rails and the edge of the embankment, or side of the excavations. This 
 is, to a great extent, determined by what is necessary to keep the ties firm, to preserve the stability of 
 the rails, and to effect the passage of the engines and carriages along the railway with every possible 
 security. Where economy of construction has been a primary object, a width of three feet and a half 
 from the rails to the outer edge of the embankment or footpath of the excavation, or from n to k, or o' 
 to l, Figs. 3180 and 3181, has been found sufficient to secure adequate firmness and stability to the 
 blocks, or cross-ties and rails. 
 
 But there is another very important object to effect, — the width necessary to secure the safety of the 
 engines and carriages passing along the railway, and which is more difficult to determine, without 
 going into the subject, in a speculative point of view. The width necessary to prevent the cars running 
 off the bank will vary very materially, according to the circumstances of the case ; the speed, the weight, 
 the dimensions, and the shape of wheels, the material forming the road-bed, the method of laying the 
 rails, the alignment of the road, whether straight or curved, <fec., all having more or less bearing on 
 this dimension to insure safety. It has been attempted to investigate this question mathematically, but 
 it is one of the few questions wholly beyond such method of determination. Its solution can only be 
 arrived at by practical observation and experience. A standard writer on railroads has calculated that 
 this dimension should, when the road is travelled at a speed of twenty miles per hour, never be less 
 than the distance between the rails of the two tracks. This, it appears to us, is unnecessarily great, 
 and failing a more rigorous solution of the question, we will assume as the proper distance outside of the 
 track, the distance very generally adopted in this country, as well as on some foreign roads, and which 
 s found to answer sufficiently well, viz., three feet. 
 
558 
 
 RAILROADS. 
 
 Supposing the width of gage to be 4 feet 8J inches, ov to outside of rails to be five feet one inch 
 between the tracks six feet ; and the breadth on the outside of the rails three feet on each side ; wo 
 have, then, the width of the entire road, at the level of the rails, or, between lc and l , Figs. 3181 and 
 3180, twenty-two feet two inches. The only remaining questions for consideration, are the slopes g k, 
 h l, required for the filling of the road, and the width required for the drainage of the excavations. The 
 depth of the filling is usually two feet or two feet three inches, and a slope of one foot horizontal, to one 
 foot perpendicular, is found to be sufficient. 
 
 The width of the drainage eg, hd, Fig. 3180, will vary, according to the quantity of water required 
 to be conveyed off ; but one foot and a half on each side, at the bottom level, is generally Lund 
 sufficient. 
 
 We have, then, the width of the excavations at the bottom level, as follows: 
 
 feet, inches. 
 
 ’’wo lines of railway, including rails 10 2 
 
 Width between the two lines 6 0 
 
 Width on the outside of rails 6 0 
 
 Width required for the slopes 4 0 
 
 Width for the drainage .' 3 0 
 
 29 2 
 
 which will be the width /V, c d, Fig. 3180. 
 
 And for the embankments, or Ik, Fig. 3181, which require no width for drainage, three feet less, or 
 twenty-six feet. And where the slope of the embankments is one and a half to one, the width at the 
 bottom level, so called, (two feet three inches below grade,) is thirty-three feet nine inches. 
 
 Slopes of the excavations and embankments. — Having now ascertained the width, it is next necessary 
 to determine the angle to be given to the slopes of the excavations and embankments. These 
 depend, in some degree, upon the depth of the excavation, or height of the embankment ; in the former, 
 when the material is sand, gravel, or gravelly clay, a slope of one and a half horizontal, to one perpen- 
 dicular, is quite sufficient ; and in excavations, up to thirty or forty feet, this slope has been found to 
 stand very well. In some descriptions of clay a greater slope is given, sometimes as much as tw'o 
 to one. The embankments are generally made with the same slope as that of the excavations ; and it 
 is presumed that, with whatever slope the excavation will stand, the embankment formed of the 
 material from such excavation will stand with the same angle of slope. 
 
 On the English railways the slopes are covered with a layer of soil, which is procured from the base 
 of the embankments, or from the top of the cuttings ; this layer of soil is spread over the face of the 
 slope about six inches thick, or of the thickness which the soil from those places w'ill yield. It is of 
 great importance to the security of the slopes, that the soil should be laid on as soon as possible, after 
 the excavation is made, or the embankment consolidated ; and sown wdth grass or clover, or both, to get 
 a turf upon it before the slopes are affected by the action of the weather. By doing so slopes will often 
 stand, where, without the soiling and turf, or when exposed to the action of 
 the weather, they will not stand. This is very much neglected in this <J~ 
 
 country, and the conseauonce is, the cuts are in general either badly 
 drained, or a gang of hands are constantly at w T ork to keep the ditch free 
 from the wash of the slopes ; and it is a good practice to sow the slope 
 with some hardy grass-seed, or defend it from washing by loose stones 
 thrown over the bank. 
 
 In these figures we have shown the slope of the excavation to run 
 down to the bottom of the drain. In some cases, where stone is plentiful, 
 and where there is an excess of cutting, side walls, similar to Fig. 3182, 
 are built, to retain the sides of the excavation, the line p q showing, in that 
 case, the line of the slope. In such cases, stone drains, similar to that shown at g, are made to still 
 further diminish the width of the railway. The propriety of doing this is, however, entirely a matter 
 of calculation. 
 
 Foundations for the cross-ties. — The line having been formed to the proposed inclination longitudi- 
 nally, it is then levelled transversely. But, as the material constituting the base of the railway, in the 
 excavations and embankments, is rarely a proper material for a road-bed, it is necessary to cover these 
 surfaces over with some material which will allow the water to drain off from the bottom of the 
 ties, and which will likewise form a sufficiently firm foundation for the ties to rest upon. This is gen- 
 erally done by a layer or coating of broken stone, or clean gravel, whichever is found the least ex- 
 pensive. 
 
 The drainage having been effected, and the under coating of broken stone having been all spread 
 upon the line, the next operation is setting the blocks or ties. 
 
 On all the excavations where stone blocks can be had at a moderate cost, and on the embankments 
 which are perfectly consolidated, which, by the way, is never sufficiently the case on a new road, they 
 may be used ; but upon high embankments made of clay, and which are constantly settling down, it is 
 found most advisable, in the first instance, to lay down wooden sleepers or ties, stretched across from 
 one rail to the other. 
 
 It has been the custom in England to lay the rails on stone blocks, which rest on a laj-er of broken 
 stone about nine inches thick, and the whole filled in afterwards or “ ballasted,” as it is called, with 
 gravel. If broken stone be used, about one foot in depth will be sufficient; but if gravel be used, it is 
 customary to lay a greater depth, about two feet. This serves as a drain to take off the surface water 
 and prevents its freezing at the bottom of the ties or blocks. 
 
 The American system, however, is beginning to prevail to a great extent ; viz., the use of cross-ties of 
 wood instead of stone blocks, upon which to rest the rail In our country, where the frost is so severe, 
 
RAILROADS. 
 
 559 
 
 the difficulty and expense of setting and preserving the stone blocks is very great, and they have long 
 since been abandoned for the wood ties ; and even in England, some roads originally laid with stone 
 blocks have been taken up and wood cross-ties substituted in lieu of the stone blocks. And in fact, ii 
 the experience in this country be worth any thing, this may be considered the proper method, as most 
 modern works are now projected on this plan. 
 
 These wooden sleepers are made from eight to ten feet long, eight to ten inches broad, and about 
 five inches thick. 
 
 When the blocks are set, or sleepers laid, as the case may be, the space between the blocks, and on 
 the outside of the rails, is filled up to about three inches above the top of the blocks, or about the same 
 depth below the top of the rails. 
 
 /Seating! the chairs upon the blocks . — A seat is first made upon the top of the block, perfectly level, 
 and in the same plane as the base of the block, upon which the chair, of cast-iron, and weighing from 
 20 to 40 pounds, is to be set. Holes are drilled into the stone, about two inches in diameter, into which 
 oaken plugs are driven, Fig. 3183 ; these plugs are then bored with a three-eighth inch auger, and the 
 chair, having been properly seated upon the top of the block, an iron pin is driven through the hole of 
 the chair into the wooden plug, and which, having a head, fastens the chair to the sleeper. 
 
 3183. 
 
 3195. 
 
 Keying the rails to the chairs . — Various methods have been devised for fastening the rail to the chair. 
 Iron wedges, keys, and pins, and sometimes a union of all three, have in their turn had then advocates ; 
 but all metal fastenings are objectionable, as all are found to work loose. Wooden keys or wedges are 
 beginning to be in favor. Fig. 3184 is the rail used on the London and Birmingham Railway, and weighs 
 sixty -five pounds per yard; and which is the form of rail used upon the Grand Junction Railway. 
 
 3184. 
 
 3185. 
 
 4199. 
 
 o s a cc 
 
 X ml - - I - ' ; 
 
 3187. 
 
 These rails are secured to the chair by a wooden key, a a, Figs. 3184 and 3185. One side of the chair 
 is bevelled vertically, against which the wedge acts, and pressing against the upper side of the base of 
 the rail, forces it downwards into the chair, while it, at the same time, forces the rail against the other 
 check of the chair. These keys are made of oak and well dried, so that when driven, and exposed to 
 
 3205. 
 
 a a a- 
 
 H 
 
 ^ 
 
 
 R| 
 
 V 
 
 B 
 
 h 
 
 O 
 
 
 A -!_ ' f 
 
 H 
 
 0 
 
 ,o 
 
 
 tne humidity of the atmosphere by expanding, they act with very powerful effect in fastening the ran 
 to the chair; so much so as in some cases to split the chair. The plan B of Fig. 3184 shows the form 
 of the wedge a a longitudinally ; by this it will be seen that the side of the chair is convex; when, 
 
560 
 
 RAILROADS. 
 
 therefore, the wedge, being quite dry, is driven between the rail and chair, and expanding by the damp 
 of the atmosphere, it is very tightly compressed by the convexity of the chair, which produces a corre- 
 sponding expansion at the ends, and thus fastens the wooden wedge so securely that no working takes 
 place between it and the rail or chair. This key has, of course, no tendency, except the mere friction or 
 pressure of its sides, to prevent the ends of the rails at the joint from separating. 
 
 Fig. 3186 represents the form of chair in use on the New York and Erie Railroad, in this State, which 
 is found to answer a good purpose. The chair is complete in itself, and the rail fastened by means ol 
 it and the spikes to the cross-ties, independent of the oak wedge, which is driven in to prevent the 
 rattling of the rail in its seat, from the vibration caused by the passage of the train. It will be per- 
 ceived that the action of the wedge forces the rail down in the chair and firmly against its opposite 
 cheek. 
 
 The effect of the expansion and contraction of the rails, by the variation of temperature, amounts to 
 about the fifteenth part of an inch in a rail fifteen feet in length. It has been attempted to obviate this 
 shock by forming the ends into a half-lap joint, but with partial success only. The best thing that can 
 be done at present is to preserve the parallelism of the upper surface of the rail ; but the opening of the 
 joint is inevitable, as, from the expansion and contraction of the rail, an open joint must be left, 
 dependent in its dimensions upon the temperature at the time of laying the rails. 
 
 3188. 3190. 3192. 3194. 
 
 Fig. 31 SI is a plan of rail laid down on some of the railroads in this country; with this rail chairs 
 are dispensed with, the base of the rail being very broad, and being laid upon the longitudinal sills or 
 cross-ties, is fastened to them by the brad-headed spikes c and d, which are driven into the sills. A 
 notch is cut near the end of the rail on each side, somewhat longer than the width of the spike which 
 is driven through the notch, thus permitting the rail to expand or contract, while the flat head of the 
 spike confines it firmly to the cross-ties. , This has become a favorite mode of fastening rails in this 
 country, and may be said to be universal, sometimes without any chair at the ends, and sometimes 
 with a mere plate to prevent the ends of the rail from bedding themselves into the wood. This form 
 of rail is now known in Europe as the “ American rail.” The following are a few of the various 
 patterns of rail in use : 
 
 Fig. 3188 is the section of an experimental fish-bellied or elliptical rail, rolled by the Newcastle and 
 Carlisle Railway Company, for the purpose of ascertaining the comparative rigidity of this kind of rail, 
 and parallel rails of the same weight per yard ; the w'eight of this rail was about fifty pounds per yard ; 
 the figure shows the extreme depth, and the dotted line a b the smallest depth. 
 
 Fig. 3189 is the section of the parallel rail, rolled for the purpose above described, the weight of 
 which was as nearly fifty pounds per yard as it could be rolled. The area of the wearing or top part 
 of the two rails is precisely the same, as likewise the breadth of the base ; but they differ in the depth 
 and thickness of the middle part of the rail. 
 
 Fig. 3190 is the section of a parallel rail, used upon the Liverpool and Birmingham, or Grand Junction 
 Railway, and weighing about sixty-two pounds per yard. The top and base of this rail are the same 
 section. 
 
 Fig. 3191 is the section of a rail used on the Dublin and Kingston Railway, and which is a parallel 
 rail, weighing about forty-five pounds per yard. 
 
 Fig. 3192 is a fish-bellied rail, made by Mr. Stephenson, and weighing about forty-four pounds per 
 yard. The entire section on the drawing shows the extreme depth in the middle, and the line a b the 
 depth at the bearing parts. This rail does not swell out at the base, being intended to be keyed into 
 the chair. 
 
 Fig. 3193 is the section of a parallel rail, of the weight of fifty pounds per yard, a few of which are 
 laid down on the Liverpool and Manchester Railway. 
 
 3201. 3202. 3204. 
 
 Fig. 3194- is the section of a rail intended for the Great North of England Railway, the weight of which 
 is about sixty pounds per yard. This is likewise a parallel rail ; the mode of keying this rail differs 
 from any of the preceding plans, and is shown in Figs. 3195 and 3196, Fig. 3196 being a section, and Fig 
 3195 a plan. One side of the chair is cast to fit the rail; on the other side of the chair a loose inter- 
 mediate wedge slides between the cheeks of the chair, shown at e ; this intermediate wedge is keyed 
 against the rail by the driving-key/, which may be driven with any degree of tightness; the interme- 
 diate key prevents the vibration of the rail from loosening the key f This chair, it will be seen, has 
 four pins to fasten it to the block. 
 
RAILROADS. 
 
 56.1 
 
 Fig. 3197 is the section of a parallel rail, laid down on the Liverpool and Manchester Railway, and 
 weighing sixty pounds per yard. In all the preceding figures of rails, both sides of the top or wearing 
 part of the rail, whereon the wheels roll, is the same ; but as it is only on one side of the rail that the 
 flanch of the wheel rolls against it below the plane of the top of the rail, the wheel on the other side 
 rolling along the plane of the surface, it is evident that there is no necessity to have both sides the 
 same. In this case the side of the top, acted against by the flanch of the wheel, is of the same outline 
 as that part of the wheel ; while, on the opposite side, the section is at right angles to the plane of the 
 top. This plan, however, prevents the rail from being turned with the opposite side to the flanch of the 
 wheel, which it is sometimes found requisite to do. 
 
 Fig. 3198 is a section of the thirty-five pounds per yard fish-bellied rail, originally laid down upon 
 the Liverpool and Manchester Railway ; the entire figure showing the extreme depth in the middle, and 
 the line a b the depth in the bearing parts of the rail. The mode of keying this rail is shown in Fig. 3199. 
 
 Fig. 3200 is a section of a fifty pound per yard elliptical, or fish-bellied rail, laid down on the Liver- 
 pool and Manchester Railway : the section of this is nearly similar to the preceding figure, except in 
 the area and weight; the keying is precisely similar; the line ab shows the depth at the bearings. 
 
 Fig. 3201 is a parallel rail, weighing seventy-five pounds per yard, and laid on the London and 
 Birmingham Railway. The mode of keying is similar that shown in Fig. 3199 ; the distance of the 
 supports, five feet. 
 
 Fig. 3202 is the section of the parallel rail, laid down upon the Liverpool and Manchester Railway, 
 weighing seventy-five pounds per yard. The top of this rail is made of the shape explained in Fig. 3197. 
 
 Fig. 3203 is another sixty pounds per yard parallel rail, which has been laid down upon the Liver- 
 pool and Manchester Railway. 
 
 Fig. 3204 is the section of the rail laid down upon the Newcastle and Carlisle Railway ; it is an ellip- 
 tical or fish-bellied rail, shown in Fig. 3205, with a convex projecting knob at the bearing points. The 
 entire figure in the plate shows the extreme depth of section at a' b', Fig. 3205, and the line a b, Fig. 
 3204, the depth near the knob, the latter swelling out the depth of half an inch more within the chair. 
 These rails weigh forty-two pounds per yard, and are laid in fifteen feet lengths, with five bearings of 
 three feet each. 
 
 The compound rail, designed with a view to correct the defect experienced in the simple rail at the 
 joint, is now receiving a good deal of attention from engineers. Several plans have been devised, but 
 all of them want the results of experience before they can be recommended for general adoption. Un- 
 doubtedly the defects of the joints are, to a great extent, remedied by the compound rail, but it is 
 questionable if in this country greater evils would not result by increasing the number of piarts of a 
 machine already so complicated and difficult to keep in repair as a railroad. 
 
 Curves on the line of railway . — It has been usual to construct the wheels for railway carriages so that 
 the outside rim is conical, or enlarged in diameter next the flanch; when, therefore, the carriages are 
 passing round a curve, the wheels being connected together by the axle, forms, as it were, a conical 
 roller, running upon the rails with different radii ; the larger radii being on the outside curve of the rail. 
 This increase in the diameter of the wheel running on the outside compensates, to a certain extent, for 
 the increased length of the outer curve of the rail ; and if the radius of the curve is not less than the line 
 which the two wheels of unequal radii would describe, the wheels will travel along the line of the curve 
 without rubbing against the Handles. But if the curve is more acute than such a line, then the flanches 
 of the wheels are the only guides to keep the carriages on the rails. 
 
 The degree of cone generally given to the tire of the carriage wheels is to make the diameter next 
 the flanch one inch larger than the diameter next the outside of the tire, the breadth being 34 inches. 
 In practice, it is likewise usual to keep the wheels at such a distance from each other upon the axles, 
 that, when travelling upon a straight line, the flanches on each side are about one inch from the rail. 
 With a view to provide against the centrifugal force of the carriages when running in a curve, it has been 
 customary to elevate the outer rail of the track. 
 
 The following table will show the elevation to be given to the outside rail, of different radii, above 
 that of the inner rail ; so that the whole amount of centrifugal force is balanced by that of the gravity 
 of the load, towards the inside of the curve. 
 
 Description of wagon and width of 
 
 Radius of 
 
 Surplus of elevation in inches, the velocity in 
 miles per hour being : 
 
 railway. 
 
 in feet. 
 
 10 miles. 
 
 15 miles. 
 
 520 miles. 
 
 30 miles. 
 
 
 250 
 
 1T6 
 
 3-04 
 
 5-67 
 
 13- 
 
 Diameter of wagon wheels 3 feet ; 
 
 500 
 
 •58 
 
 1-52 
 
 2-83 
 
 6'57 
 
 width of railway 4 feet 8 inch. ; 
 
 1000 
 
 ■29 
 
 •76 
 
 1-42 
 
 3-30 
 
 inclination of the tire of the 
 
 2000 
 
 •15 
 
 •38 
 
 •71 
 
 1'65 
 
 wheel ^ inch in the breadth, 
 
 3000 
 
 TO 
 
 •25 
 
 •47 
 
 1T0 
 
 viz., 3-1 inches. 
 
 4000 
 
 •07 
 
 •20 
 
 ■36 
 
 ■83 
 
 
 5000 
 
 •06 
 
 T5 
 
 •29 
 
 •67 
 
 J 
 
 It was a few years back the custom in this coantry, as it still is to a great extent in England, to 
 cone, as it is called, the tires of the wheels with a view to prevent the rubbing of the flaiKlies of the 
 wheels in passing the curves. The above calculations of the elevation of the outer rails includes, as an 
 element, this coning of the wheels. Theoretically and practically, with a given speed, this is correct 
 but the passenger, express, and freight trains, travelling at very different speeds without their wheels 
 Vol. II. — 36 
 
RAILROADS. 
 
 m2 
 
 are coned at different angles — which in practice would he very inconvenient, if not wholly impractica- 
 ble — the different elevations of the outer rail would not meet the necessities of the particular case 
 a9 a speed of 30 miles per hour requires an elevation some 11 times greater than a speed of 10 
 miles. It is now, in this country, the custom to disregard this coning of the wheels to the extent which 
 the theory would call for, and simply cone them to the amount of the draft (as it is called) of the cast- 
 ing, about J inch on the tread of the wheel; and engineers differ very much as to the proper amount Oi 
 elevation which should be given to the outer rail. The actual amount to meet a given speed is easily 
 estimated ; but whether it is expedient to give more or less than this, or to provide for the freight or 
 passenger trains, is as yet an unsettled question. 
 
 As there can be no doubt that the higher velocities of passenger trains, even with their less load, is 
 nroductive of greater injury to a road than the freight trains, it would seem desirable to adjust the rail 
 with the surplus elevation due the higher velocity ; if the road were essentially a passenger road, or in 
 other words, without the freight trains were largely in excess of the passenger trains, to suit the curves 
 to the latter traffic, having in view the diminution of “wear and tear” of both wheels and rail, rather 
 than an economy of motive power. 
 
 Great Western Railroad in England — Mr. BruneTs plan. — Figs. 3205, 3206, and 3181, (p. 519,) show 
 a plan apd different sections of Mr. Brunei’s plan of railway. ABCDEF and G H are the longitudinal 
 rails forming the railway ; these longitudinal rails are 14 to 15 inches broad and 6 or 7 inches thick, and 
 are made of American pine, ah' ah' and cd' cd' are double transverse ties or sleepers, which are each 
 six inches in breadth and seven inches deep ; and ef single transverse ties or sleepers, which are six 
 inches in breadth and nine inches deep. These sleepers are stretched across the line of railway, and tc 
 them the longitudinal rails are secured. 1 2 3 4 5 and 6 are piles which, in the cuttings, are from nine 
 to fourteen feet in length, according to the nature of the material, and in the embankments 12 to 30 
 l'eet, or of such a length as that they will reach from the base or formation line of the railway 6 to 8 
 feet into the original surface of the ground. The cross-ties are American pine, and the piles of beech. 
 
 3205. 
 
 The plan of construction, or of forming the railway, is as follows : the piles are driven at intervals of 
 every fifteen feet, as shown in the drawing, and in the middle between the longitudinal rails. In cut- 
 tings, they are driven from eight to ten feet into the ground, below the level of the cross-sleepers; and 
 on embankments they must be of such a length as to be driven about the same depth, or seven or eight 
 feet into the original ground. Upon an embankment of three feet they must be, therefore, ten or twelve 
 feet long, and so on, according to the height of embankment, and the kind of subsoil into which they are 
 to be driven. These piles are always to be driven to the exact depth required ; no part of the head is 
 allowed to be cut off; but if the pile does not drive to the proper depth, it must be drawn and driven 
 again. This is for the purpose of being certain that they have sufficient hold of the ground ; near the 
 head of these piles, as shown at 1 2 3 4 5 6, Fig. 3205, and at b b'f and dd\ Fig. 3206, a square shoul- 
 der, of 14 inch, is made on one side of the piles for the single ties, and on both sides of the piles 12 5 6 
 for the double ties. The ties or cross-timbers are let into these shoulders, and they are firmly bolted to 
 the piles, as shown in the drawings. The double cross-timbers are laid down thirteen inches, and the 
 single timbers nine inches below the line of the rails. Between the double timbers, as shown at g g, 
 Fig. 3205, and also at all the Other points where the longitudinal rails intersect the cross-timbers, a piece 
 of wood is interposed, which is pinned to the cross-timbers, and upon which the longitudinal rails rest. 
 
 The longitudinal rails are then laid down upon the cross-timbers, the upper surface of which is three 
 inches below the surface of the iron rails ; they are bolted to the cross-timbers with screw-bolts and 
 washers, as shown at nnnn, Fig. 3205, and by a larger scale in Fig. 3207, ef being the cross-timber, 
 and A B the longitudinal timbers ; the latter, it will be seen, is let into the cross-timber a little, the 
 single cross-timbers being deeper than the double cross-timbers. The head of the bolt and washer is 
 countersunk into the upper surface of the longitudinal rail, as shown in the figure. One of these bolts 
 is put in at each of the points of intersection of the longitudinal rails with the single cross-timbers, and 
 vwo bolts at each of the points of intersection with the double timbers. 
 
 When the piles are firmly driven, the cross-timbers bolted to them, and the longitudinal timbers 
 bolted to the cross-timbers, then sand, or finely screened gravel, is beat or packed underneath the longi- 
 n dinal timbers, until a base or bed is made for them to rest upon, perfectly firm, solid, and compact. 
 
 Fig. 3208 shows a section of the rail used, which weighs from 4 3 to 44 pounds per yard, and which 
 
RAILROADS. 
 
 585 
 
 rests upon and is secured to the hard-wood plank and timbers of the longitudinal sills, and is of the de- 
 scription known as the U or bridge rail. 
 
 As shown in the figure, the rails have a slight bevel inwards. 
 
 The width or gauge of the railway is 7 feet 2^ inches, from centre to centre of the rails ; and the 
 width between the centres of the inside rails is 6 feet. 
 
 A few instances occur in this country of the use of stone blocks for the support of the rail ; but they 
 form the exception, it being found that the wear and tear of machinery on the stone track is much 
 greater than on the wood, and in consequence, the use of the latter material for the support of the 
 rail has become universal. Upon this depends in a great measure the perfection of the road. The 
 point in which our roads present a great inferiority when compared with the English, is in the want of 
 complete preparation of the foundation. All the refinement of science, applied to the form and dimen- 
 sion of rails, chairs, engines, &c., is useless, if the foundation be liable to be thrown by frost, or to dis- 
 placement from any cause. To prevent this, too much care cannot he given to the nature of the mate- 
 rial forming the road-bed, and to the position and preservation of the ditches. All material impervious 
 to water should be excavated from the bed of the road to the depth at least of two feet, and its place 
 supplied by clean gravel. The sleepers or cross-ties of chestnut, cedar, oak or other durable wood, ac- 
 cording to the locality, are laid transversely, at intervals of about two feet. These ties should be at 
 least 6 inches deep by 7 or 8 inches wide, and for the narrow gauge 8 feet long. Upon these cross ties 
 are to he spiked the iron rails. 
 
 The rail is usually secured in the chair by the brad-headed spikes which hold the latter to the ties, the 
 notch in the rail for the spike being elongated so as to permit the expansion and contraction of the rail, or 
 else the chair is fastened independently of the rail, and the latter prevented from rising out of the chair 
 by the latter being made to conform to the shape of the rail, so that it cannot be removed from its 
 chair but by drawing it out in the direction of its length. At the intermediate cross-ties the rail is 
 secured inside and out by the brad-headed spike driven into the tie on each side, and lapping over the 
 base of the rail. The rail may be further secured in the chair by a wooden wedge, sawn to a taper, 
 and driven into the chair against the bottom, side, and top of the rail, one side of the chair being cast 
 to receive it. It is not advisable, however, to make the fastening of the rail in the chair dependent 
 entirely upon the wedge. The chair should be safe against accident, were the wedge to drop out ; 
 out the use of the latter should be to perfect the joint, and prevent the small motion in the chair oc- 
 casioned by the vibration of the rail, which in the end might prove the destruction of the chair. The 
 spikes should be machine-made, with chisel points, and weigh at least half a pound each, and occupying 
 in length the dejrth of the cross-tie. After the rails — we have supposed the H or U section, of about 
 from 60 to 80 pounds per yard — are laid and spiked, and the line of rails adjusted to their proper 
 adjustment, the ballast of clean gravel is brought into the road and deposited between and around 
 the cross-ties, packed well underneath them with the shovel and rammer, and levelled off to the plane 
 of the bottom of the rail, nearly. This is the method, with some modification, which prevails pretty 
 generally in the construction of the modern railroad. A longitudinal bearing under the rail, into which 
 the cross-ties are framed something- similar to the Western Railroad in England, is occasionally adopt- 
 ed ; but its want of simplicity, as well as other defects, has occasioned its disuse. 
 
 ROLLING STOCK. Under this term are included the locomotives and cars. The distinctive feature 
 of the American locomotive will be found under its appropriate head. Our cars are still more peculiar. 
 Whilst the English, adopting the stage coach as their model, made their cars with compartments re- 
 sembling coach bodies, generally three to each car, and supported on but two sets of wheels, we, adopt- 
 ing a new and distinct construction, have adopted a long undivided car, supported near the ends by 
 trucks like the forward trucks of our locomotives. Each truck has not less than two sets of wheels, 
 sometimes three, and in very rare instances four. Passenger cars are provided with seats for from 40 to 
 60 passengers. Most of the cars are entered at the ends from the end platforms, but in some, as in the 
 Jersey Railroad cars, the entrance for passengers is in the centre. 
 
 The freight cars are in general construction similar to those for passengers, hut shorter. On a few 
 roads the short four-wheeled cars are adhered to, and when slow speeds are preserved they are more 
 economical, less dead weight in proportion to the weight carried, and easier moved at the stations. 
 Freight cars are either open or boxed; ballast cars are usually two wheeled, and arranged so as to be 
 capable of being dumped. 
 
 The chief objection to our present system of cars, resulting in part from unnecessary speed, is the 
 amount of dead, weight drawn in proportion to their freight ; and even this is disproportionately increased 
 by the often unnecessary hauling of empty or far from full cars. We annex the following table from 
 the Report of the New York Commissioners for 1856. 
 
 The following tabular statement gives the average cost per mile, for building and manning the road; 
 also the average amoimt of freight in tons, and the number of passengers for one year : 
 
 Average cost per mile of road, . 
 Of equivalent siugle track, . . 
 
 Average cost of locomotive en- 
 gines and fixtures, .... 
 Average cost of passenger and 
 
 baggage cars, 
 
 Average cost of freight cars, 
 Average number of miles of road 
 for one locomotive, .... 
 \verage number of miles of road 
 for one passenger car, . . . 
 
 $50,792 
 
 88 
 
 36,833 
 
 73 
 
 9,625 
 
 50 
 
 2,011 
 
 50 
 
 631 
 
 50 
 
 3.43 miles. 
 
 Average number of miles of road 
 for one freight car, .... 
 Average number cars per train, 
 
 passenger, 4.5 
 
 Average number per train of 
 passengers, .... 72.6 
 Average number per cai-, of 
 passengers, .... 16.13 
 Average number of tons of 
 non - paying weigh# per 
 passenger, . . . . 1.17 
 
 0.26 miles, 
 freight, 18.2 
 “ tons 71.2 
 
 “ “ 3.91 
 
564 
 
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RAILWAY" BARS. 
 
 66? 
 
 The great weight of the locomotive and of the carrying stock generally, has led to various expedient, 
 to avoid this difficulty. Rope railways, that is railways in which the cars were drawn by ropes or chains 
 by means of stationary engines, had long been used in mining districts to overcome steep gradients. 
 This system was adopted with some ingenious modifications, to propel cars on a level track, on the Lon- 
 don and Blackwall railway. But it was found uncertain and expensive and given up. In fact, at present 
 there are but few inclines in this country worked by stationary power, it being found more economical tc 
 work with the locomotive on zig-zag or Y tracks to overcome steep gradients. 
 
 As an improvement on the rope railway, Clegg and Samuda introduced the atmospheric railway upon 
 the Dublin and Kingstown road, where it worked so successfully for a series of years, that it was intro- 
 duced on the London and Croydon Railroad, but it proved a failure. As an expedient it was very in- 
 genious, and may perhaps in some form be serviceable on very short lines. Suppose a large pipe to be 
 laid down on a road, and that at one end of this pipe were placed an air-pump for withdrawing the air, 
 and at the opposite end a piston, working accurately in the pipe. On pumping out the air from the 
 pipe, the atmospheric pressure upon the piston would didve it along the tube. In order that the piston 
 and the carriages might travel together, much in the same way as the short tube, or pencil-holder 
 inside a pencil-case, travels with the outer tube or ring, — some connection is necessary between the 
 piston within and the cars without the tube. The arrangement employed on the line from Kingston to 
 Dalkev, a distance of If mile, is as follows : 
 
 In this railway the vacuum-pipe was about 15 inches in internal diameter ; it was of cast-iron, and 
 was laid down in the same way as the large water mains, between the two rails of the railway. After 
 the pipes were cast, a cutter was passed through them in the direction of their length : they were then 
 raised to the temperature of melting tallow, and a mop dipped in that material was passed through 
 them, and being followed by a wooden piston, the inside became coated with a thin surface of tallow, 
 which soon acquired great hardness. This was found to be an excellent sui-face for the piston to travel 
 against. On the top of the tube was a narrow opening extending the whole length, closed by a valve 
 so as to render the tube air-tight. This valve was a continuous flap of leather, on the upper and under 
 sides of which plates of iron were riveted, the inner surface of the lower plate formed to the curve of 
 the pipe, the upper plate and the leather being made a little wider than the opening or slot, and extend- 
 ing over it on each side. This continuous valve was hinged on one side to a projecting rib, and the 
 other edge fell into a groove containing a composition of wax and tallow, which, when melted, sealed 
 up the pipe, and made it sufficiently air-tight for the working. A flap called the weather-valve, protected 
 the apparatus from the weather. The piston contained within the tube was furnished with a rod 1+ oi 
 15 feet in length, to which were attached rollers for opening the air-tight valve behind the piston as it 
 advanced along the pipe. The piston was connected with tbe first carriage, or driving-car, by means of 
 a coulter : to the driving-car was attached a copper vessel, several feet in length, heated with coke, for 
 the purpose of melting the wax and tallow when the valve had been pressed down by the apparatus. 
 
 It will be understood, then, that the train of carriages moved on rails as in the ordinary railway : 
 but between the rails the tube with its enclosed piston was situated ; and that an air-pump worked by a 
 stationary steam engine exhausted the air in the tube in front of the carriages. The speed of the train 
 would evidently be in proportion to the rapidity with which the air could be pumped out. It was found 
 that an exhaustion of 15 inches could be produced in about 2 minutes, and that a speed of 50 or GO 
 miles an hour could be produced. 
 
 RAILWAY BARS .— On the manufacture and form of. The mass out of which the rail is rolled is 
 called a “ pile,” and is composed of a number of plates cut from rolled bars to a length suitable to the 
 convenience of handling, and the dimensions of the close-furnace in which the piles are placed to receive 
 a welding heat. The piles have a bed and cap plate of double the width of the other plates, which 
 keep the pile together, and are mostly of superior iron .See Fig. 3196, in which A represents the cross- 
 section of the pile. 
 
 3198.— T or edge rail. 
 
 The furnace is closed up to prevent the iron from burning on the surface before the middle of the mass 
 is brought to a welding heat. It requires skill and practice to judge of the degree of heat necessary to 
 insure a sound rail. If the heat is not sufficient for an effectual weld through the whole mass, the rail, 
 when put to the severe action of the locomotive-wheels, will crush down, or peal off in laminae ; and 
 when the rail is finished it is not easy to see a defect in the welding, as the surface may appear sound. 
 For this reason a close and competent superintendence of the manufacture is much more important than 
 the most careful inspection after the work is done. It often happens that a careful headman, who man- 
 ages the rolling, will send back a pile to the furnace, before or after passing it once through the rolls, to 
 receive a better heat. The good quality of a rail is as much dependent on effectual welding as on tha 
 quality of the metal. 
 
566 
 
 RAILWAY BARS. 
 
 To obtain a more solid and durable surface on the top of the rail, it has been proposed to use a ham 
 mered bar of double the usual thickness for the cap-plate of the pile, which would remain a solid ma- 
 terial of considerable body after the rail is finished. See Fig. 3197, in which A represents the cross- 
 section of the pile. 
 
 In the composition of the pile no scraps or short pieces should be admitted, for the reason that the 
 process of rolling and extending the mass lengthwise is adverse to welding the cross-joints between the 
 pieces, and so far the rail is diminished in strength and solidity. Scraps and trimmings had better be 
 wrought into common bars, to be worked over again in the smith-shop. The heavy rail is a finished 
 piece of work, and so expensive that its efficiency should not be endangered by the use of improper 
 materials. 
 
 The pile should always be of sufficient weight to afford a surplus in length, so as to cut the rail of the 
 desired length entirely clear of the fag-ends. Rails are often defective and give way at the ends while 
 other parts remain sound, for the want of due attention to this matter. 
 
 3199. — Double-headed rail, to be reversed. 3200.— H-rail. 
 
 Great care should be taken in the straightening and trimming ; and the first step is to see that the 
 large cast-iron plate upon which the rail is laid while hot from the rolls is straight and out of wind — as 
 tLe rail, being lifted and slammed down while soft, will conform to its surface, and retain a twist when 
 cola if the plate should be in wind. This is a most mischievous fault, and can never afterwards be per- 
 fectly corrected. Though the surface may be brought to a line longitudinally, and the base adjusted on 
 the bearings, the pressure on the top, varying from side to side, will produce a rocking action, lending 
 constantly to loosen the rail. 
 
 Close attention should also be paid to accurate straightening, as even a slight undulation on the sur- 
 face will produce, at the ordinary velocity of the train, (30 miles per hour,) a sensible vibration, un- 
 pleasant to the passenger, and injurious to the road and train. 
 
 3201. — Bridge-rail. 3202. — Three-part rail. 
 
 To prevent rails having these defects from being brought into use, a severe inspection should be 
 applied to them. Each rail should be placed on a strong bench, in length equal to that of the rail, and 
 the surface plated with iron in several places ; these plates should be dressed to a correct fine and out 
 of wind, which will at once detect any twist or crook that may be in the rail. 
 
 The circular saw is now generally used in trimming, which is a great improvement over the chisel, as 
 it leaves the section of the rail undisturbed — a very important matter in making even joints. 
 
 In considering the form of the railway bar, it may be first observed that the more simple and com- 
 pact the section, the more sound will be the rail. It is obvious in viewing a section of the pile, (see Fig. 
 3196,) that there are a number of joints between the plates to be welded, and that each plate must of 
 
RAILWAY BARS. 
 
 5G7 
 
 necessity be reduced to a thin lamina in extending the mass to the length of a rail, and that the strain 
 on the weldings and materials will be much less in one form of section than another; therefore, in de 
 signing a form, it is well to give to this matter its due consideration. 
 
 The X or edge rail, set in chairs, and the double-headed rail, Figs. 3198 and 3199 have been exten. 
 sively used in Europe ; but it is said that the H, and bridge or U rails, American designs, are coming 
 into favor there. They have long been the favorite patterns in America, and do now divide the opin- 
 ions of professional men and railway companies, so that the two are placed in competition on extend ve 
 divisions of the same line, and on different roads. Each has its peculiar merits. 
 
 The H-rail has the advantage in simplicity and beauty of form, and may have in solidity, by a mod 
 ification of the section. The head and base are generally made too light, (see Fig. 3200.) It also affords 
 a better base for its support on the bearings. 
 
 The U or bridge rail has the advantage of perpendicular sides to support the head, without projections 
 subject to be split off, like the H-rail. It also offers better facilities in its hollow form to secure strone 
 and even joints, by the insertion of an iron core at those points. See Fig. 3201. 
 
 3204. 
 
 3203.— Two-part H-rail. 
 
 But, after all the exertion of talent and skill for the last twenty years to perfect a line of road with 
 the usual form of rails, it still remains very deficient in smoothness and stability at the joinings, and it 
 is feared will continue to be so while the rails are made in independent, separate, solid pieces 
 
 The perfection of a rail would be one of sufficient and uniform strength— rolled, or made by other 
 means — in one piece, without joints the whole length of the line ; but this being impracticable, the effort 
 is now to approach it by a new device, which is to form the rail of two or more pieces, say 20 feet in 
 length, and to splice them together, breaking joint, so that each part shall act as a splicing-plate to the 
 others where their ends meet. 
 
 A three-part compound rail of cast and wrought iron has been on trial for some time on a line of 
 heavy traffic, and stands the test of heavy engines remarkably well. It is more elastic than a solid rail 
 of the same weight, and the line is more uniform in strength, and of course more easy to the passenger, 
 the train, and the road. It is apparently so far a considerable advance towards theoretic perfection. 
 See Fig. 3202. 
 
 The next attempt, having the same object in view, is a compound rail of two parts, bolted together 
 with a vertical joint, and each part breaking joint with the opposite part. It is now under trial in a 
 section of an important road, and is said to promise well. See Fig. 3203. 
 
 The third plan, which yet exists only in model, is also a compound rail of two parts, having a vertical 
 joint, and breaking joint. But each part is concave on the inner side, so that when they are combined 
 they form a tube, in which, at each cross-joint, is inserted an iron core which fills the tube for a short 
 epace, and is designed to compensate the loss of strength occasioned by the semi-cross-joint, and to pre- 
 vent vertical slipping between the two parts. 'The edges of this compound rail are precisely alike, 
 which renders it capable of being twice reversed, thus possessing two surfaces to be worn out in succes- 
 sion, thereby doubling the durability of the rail. But without actual trial it is questionable whether 
 this presumed advantage will compensate the expense of the stancheons intended to support the rail in 
 its proper position. The form, however, may readily be modified, (see Figs. 3201 and 3205.) Fig. 3206 
 shows the break-joint on the top, the dotted lines representing the core. 
 
 A fair statement of the distinguishing properties of these three new American devices will now be 
 attempted, leaving a comparison of their merits to those competent to make it, and to the test of 
 experiment. 
 
 The leading property in the three-part rail is, that the cap piece is the only part subject to renewal, 
 and being but about one-third of the whole weight, must greatly reduce the cost of repairs. The means 
 of securing the cap-piece against endwise movement under the stroke of the locomotive- wlie.e.ls, is by 
 
568 
 
 REFRIGERATOR, THE DRY. 
 
 3206. 
 
 assing keys through the tongue of the cap-piece and fitting in stop-notches cut in the top of the 
 earing- rails. A better mode of security in this important matter is suggested by the inventor, which 
 is to let the tongue of the cap-rail project downwards sufficiently low that the bolts which hold the 
 base-rails together may pass through it also. This compound rail loses about one-third of its strength at 
 each cross-joint; but the objection may be relieved to a considerable extent by inserting an iron core at 
 each cross-joint under the tongue of the cap-piece. This form of a composite rail necessarily carries 
 with it one great objection in view of a perfect surface, as the latter is broken at the end of each cap- 
 rail by a thorough cross-joint, presenting a notch for the wheels to pass over of more or less extent, pro- 
 ducing more or less jar at all those points. 
 
 The two-part H-rail, the second noticed, and the two-part tubular rail each equally possess the ad- 
 vantage of a surface but partially broken, as the cross-joint extends only to the nriddle of the surface, 
 leaving the other part a bearing to the wheels in passing over. They also equally possess a provision 
 against end-tlirusts, in merely combining the two parts. When the surface is 'worn out, the whole rail is 
 lost in each case. The two-part H-rail loses half its strength at each cross-joint ; the tubular rail, in 
 consequence of the core, is of nearly equal strength in all parts of the line. 
 
 REFRIGERATOR, The Dn/, for Family Use. A. S. Lyman’s. Fig. 3207 is an interior view. The ice is 
 placed in the chamber A, and the air in contact with it being cooled and condensed, and therefore rendered 
 heavier, flows down through the grate R, and the descending cold air flue C, in the direction of the arrows. 
 It is discharged up through the opening in the hack part of the bottom of the lower drawer. The warmer 
 air in this drawer rises up through the opening M, in the division hoard above and onwards, finally 
 passing up the flue D, and over again upon the ice : thus a current is formed, as shown by the arrows. 
 
 For the purpose of showing more clearly its inter- 
 nal arrangement, the middle drawer is represented as 
 partially open. This shows the opening M, through 
 the division board on which that drawer rests, and 
 the opening N, through the back end of the bottom 
 of that drawer. This opening If, is now closed by 
 the division board. When the drawer is closed, these 
 openings M and N coincide, and the air flows freely 
 through them, as it is forced from the lower to the 
 upper drawers by the superior weight of the column 
 of cold air in the flue C. Tbe back end of the drawer 
 cuts off all connection with the refrigerator, so that 
 no air can flow out when it is open. The cold air in 
 this drawer being heavier than the air outside, re- 
 mains in it, unless there are currents in the room, 
 which at most can only sweep the air from this drawer. 
 
 Some of the gases set free in refrigerators are ab- 
 sorbed by ice, or rather by the pure water as it is 
 dissolving from ice ; but that alone will not absorb all 
 impurities, nor prevent a refrigerator from accumu- 
 lating had odors, as is known practically by all who 
 have used refrigerators for a sufficient time. 
 
 In order that the air may be rendered perfectly 
 pure, the charcoal filter S, is placed in the back part 
 of the drawer, so that the air in its rounds is constantly being filtered through the charcoal, and thus 
 deprived of all its impurities. The water from the melting ice runs into the gutter G, and off by a trap 
 pipe not. shown. These refrigerators are all made double as represented, and the spaces, which are from 
 l|- to 3 inches wide, filled with pulverized charcoal ; this increases the weight and cost somewhat, but it 
 is essential to practical success. 
 
 REGISTERING AND NUMBERING MACHINE, Bahanovvski’s patent. The several machines 
 patented by Mr. Baranowski are all dependent on one particular arrangement of wheels or disks, of 
 which he gives the following preliminary description : 
 
REGISTERING AND NUMBERING MACHINE. 
 
 569 
 
 The 'wheels or plates d and b, Fig. 3209, turn on their centres B and A, and ■when the tooth e falls 
 into one of the notches in b, it moves b round one-tenth of its circumference, as there are ten notches in 
 the wheel b. The spaces between the notches in b are arcs of the same circle as d, so that b is always 
 stationary and fixed, except when moved by the tooth in d once for each revolution of d. b is fixed to 
 a, the edge of which is engraved with the figures from 0 to 9, as shown in Fig. 3208. The cogged- 
 
 3208. 3210. 
 
 wheel c is also fixed to a, and works into a cogged-wheel of the same size A turning on the same centre 
 as d, the edge of which is also shown in Fig. 3208. d l is fixed to this last cogged-wheel f, and is of the 
 same form and size as d. b' is fixed to a 1 , the edges of which are shown in Fig. 3208, and is of the 
 same form and size as b. Again: Fig. 3208, b 2 is fixed to a 2 , and is turned by d 2 , which is fixed to 
 working into the cogged-wheel c 1 : b~ and d 2 are also of the same size and form as b and d. a 1 and a 2 
 have also the figures from 0 to 9 engraved upon their edges. All the plates or wheels move freely on 
 their cylinders or centres, A and B respectively, although it will be seen that no one of them can move 
 without moving all the others, at intervals of time dependent upon the number of notches in the wheels 
 b, b 1 , and b 2 , respectively, and also upon their respective distances in the arrangement from the first 
 mover d. The operation of counting proceeds thus : — The first revolution of d moves a one-tenth, or 
 puts the unit in the place of the cipher on a; ten revolutions af d, or one of a — that is, one revolution 
 
 3212. 
 
 3211. 
 
 of d' (tor the cogged-wheels are equal in size) — moves d 1 one-tenth, or puts unity in the place of the 
 cipher on a 1 , or shows ten where there is 0, 0, 0, in Fig. 3208. One revolution of as 1 , that is, one revo- 
 lution of d", (for the cogged-wheels are of the same size,) moves d 2 one-tenth, or puts unity in the place 
 of the cipher on a 1 , or shows one hundred where there is 0, 0, 0, in Fig. 3208, and so on till the arrange- 
 ment shows 9, 9, 9, where is 0, 0, 0, in Fig. 3208. 
 
 It is obvious that the notches in b b 1 and 5 2 need not be each ten in number, nor need there he pre- 
 cisely such three wheels ; but there may be, for instance, only two, (see Figs. 3210 and 3211,) b having 
 twelve notches, and b 1 twenty notches ; and in such a 'case, the numbers on the edges of a and a' might 
 
570 
 
 REGULATOR, STEAM. 
 
 represent shillings and pounds. It will also be seen, by examining the Figs. 3208 and 3210, that Fig- 
 3210 differs slightly from Fig. 3208, without affecting the peculiar character of the arrangement. The 
 same letters show the same parts in both figures. 6, the unit wheel a, and d' are all fixed to the axle 
 A, which turns upon its centres. In Fig. 3208 the corresponding wheels are loose on A ; d' works into 
 b\ as in Fig 3208 ; and as f is fixed to b\ and c to a 1 , and f and c are of the same size, and work into 
 each other, every complete revolution of a is attended with a partial revolution of n‘ through a space 
 measured by the distance between any two notches in b\ Fig. 3211. The object of this variation ii, 
 the Figs. 3208 and 3210 is to bring the numbers on the edges of a and a 1 close together. 
 
 Again : if d had two teeth, two notches of b would be moved round at each revolution of d, and the 
 odd or even numbers on a "would be presented from time to time where there is now 0, 0, 0, Fig. 3208, 
 according as the arrangement was started with 1 or 2. If started with 1, it would skip 2, 4, 6, &c., and 
 show 1, 3, 5, <kc. ; if started with 2, it would skip 1, 3, 5, &c., and show 2, 4, 6, &c. The Roman method 
 of notation, or any other signs or symbols expressive of numbers, can be substituted for the Arabic 
 figures, and can, by means of this arrangement, (modified so as to facilitate and vary its application,) 
 be made to appear at 0, 0, 0, Fig. 3208. 
 
 The manner in which this simple and ingenious arrangement is applied to the numbering, stamping, 
 and registering railway tickets, for example, is thus described : 
 
 Fig. 3212 is a sectional view of the side of a machine of this description. R R is a cylinder which is 
 movable up and down in the frame S S. The top P, upon which the blow with the hand is to be given, 
 is always kept up some distance above S S by a spiral spring upon R R. The whole of the machinery 
 forms part of R R, and moves up and down with it, except the rack X, and the clicks b and b, which 
 are fixed to S S. When R R is struck down, a tooth of the wheel c passes beyond b, and when R R 
 rises again to its place, the wheel c is turned one tooth by the position and resistance of b ; d is a click 
 to keep c fixed, as R R descends. The arrangement here is the same as shown in Fig. 3208, only there 
 are four wheels with figures on them instead of three, as the number shown is any short of ten thou- 
 sand. There are also two sets of figured or marked wheels, one above the other, and made to move at 
 the same time by the cogged-wheels on the middle axle g. Figs. 3212 and 3213. On the lower set the 
 numbers project to be used as stamps, the neighboring parts being cut away, as shown in the wheels A, 
 Fig. 3212. The upper set appear at H, Fig. 3214, so that each number from time to time is both 
 stamped and registered. The segment of a wheel W, Fig. 3212, to which is fixed an arm carrying a 
 small elastic roller T, works into the rack X, and at each descent of R R is thereby carried over the 
 under side of the apparatus Z Z ; and this surface being charged with printing-ink, the roller T inks each 
 projecting figure before it reaches the paper below. 
 
 REGULATORS. Clarks' Patent Steam, and Fire Regulator. Even in the earliest application of steam, 
 regulators were contrived for controlling the draft of the fire by the pressure of the steam in the 
 boiler, by which an even pressure may be maintained and no greater quantity of fuel consumed than 
 may be necessary to maintain the desired pressure. Figs. 3215, 3216, illustrate the most successful and 
 practical of these contrivances, patented by Patrick Clark, in January, 1854. Both figures are in 
 section. The construction can be readily understood. The steam trom the boiler is introduced 
 beneath a vulcanized rubber diaphragm, upon which rests a piston I , weighted like a common 
 safety valve to its lever H, as rod K is attached, which connects with the damper in the chimney 
 or flue. Fig. 3215 shows the position of the diaphragm and piston when the pressure in the boiler is 
 
REGULATOR, STEAM. 
 
 571 
 
 below that required ; wben the pressure exceeds the desired pressure, the diaphragm and piston are forced 
 up, and the damper begins to close, till it attains the 
 position, fig. 32 1G, when the draft is entirely shut. 1 The 
 amount of pressure is controlled by the sliding weight or 
 pea on the steelyard arm H, as shown in fig. 3216. The 
 diaphragm is composed of a cup or cylinder, and the 
 patentee claims “ the combination of a cylindrical dia- 
 phragm with a cylinder and piston,” by which any de- 
 sired amount of motion may he given from one inch to 
 ten feet, but for a movement not greater than an inch, 
 
 haying placed on its side or face a set or series of dies, each of which dies is placed equidistant from the 
 axis of the disk and from each other, and are intended to be brought, one to the place of feeding and 
 another to the place of heading, and one to the place of discharging, all at one and the same time 
 while at an intermediate and alternate time the disk may revolve, and by such revolution bring tire 
 next set of dies to the respective points for the before-named operations to be performed, the disk r u 
 
RIVETING MACHINE. 
 
 572 
 
 maining at rest for the purpose of allowing such operations to take place, but cutting off the wire or roil 
 that has been fed in as the disk and dies revolve, and holding and conveying it until the work is com 
 plete ; that is, until the rivet is headed and discharged, and so continuing their operations m succession 
 so long as it shall be desired. 
 
 I arrange a table a upon which I place a disk b having its several dies c, and its outer edge being in 
 the form of a ratchet d , and which may he caused to revolve by the pawl e, or any equivalent mechanism. 
 This may be understood more clearly by referring to Fig. 3219 of the drawings, this being a plan oi 
 these parts, although the same parts are known by the same references in all the drawings. Above the 
 table is the main shaft, from which is conveyed motion to all parts of the machine. A double acting 
 crank, by an intermediate connecting lever g, acts upon the pawl e to cause the disk to revolve at the 
 Draper time, and to the proper distance ; while a somewhat similar arrangement hears a like relation 
 through its connecting-rod h to the discharger i, worked by an intermediate lever k. At the back of 
 the pawl e‘ is a spring /, which keeps the pawl up to its work at all times; there is, besides, a strong 
 coiled spring, designed to keep the disk in its place firmly to the table ; a planihg-board n is used 
 to plane off and level the head after the header or meshing tools have done their work. This tool 
 may be constructed with a projecting point or lip to fit in a recess in the face of the disk, and this lip 
 will cut the nick in the head of the screw. This planing tool is placed immediately in front of the dis- 
 charger ; behind the discharger is a stop or gage piece v placed in an oblique position, which serves 
 the double purpose of a gage for the length of wire to be cut off, and as a clearer to throw off the work 
 from the disk after it has been discharged from the dies. I will here add, that I have intended to use, 
 if necessary, a lock-up for my disk ; this would regulate the disk by stopping its motion at one precise 
 place at each stop, in case it should fall a trifle short or overreach the desired point by the inaccurate 
 action of the pawl. This lock-up may be applied in many ways, but can be well applied by attaching a 
 wide piece to the end of the discharging lever, and upon it placing two pins instead of one; one of these 
 could have a long bevelled or taper point to enter one of the dies, and thus, as it is pushed in to the full 
 size, will bring the disk to the exact place to receive the other, (the discharging pin ;) this discharging 
 pin is for operating upon a headed rivet to discharge it. 
 
 Fig. 3217 shows the action of the heading hammer. This hammer has several hammer-faces, to 
 act upon as many rivets or blank screws, and gives by this means as many blows upon each one as 
 there are of these faces ; that is, one acts upon the head 
 of the rivet in one die at one blow, and the same one 
 acts upon the next rivet after one move of the disk, and 
 so on, while the one acted upon first is acted upon by 
 the second hammer-face, and so on to the finish. This 
 hammer is shown at o, and is worked by a connection p 
 to an eccentric or crank g, by which it is raised and low- 
 ered in its operation, and presses or crushes down the 
 metal, and forms a head in the rough where a flat head 
 is to be formed, whiie the round head is produced by a 
 hollow or concave in the face of the hammers. 
 
 I have used two, three, or more of these hammer- 
 faces as before stated, for the more perfectly pressing 
 and consolidating the metal, as it might not be per- 
 fectly solid by a single blow, particularly when the 
 metal is used in a cold state, as is generally the case for blank screws, while heated metal is most 
 generally used for rivets. I also use one hammer having a chisel-face, which may be pressed into the 
 head and form a nick, when it is desired to form nicks. 
 
 I provide a tube r through which the wire or rod may be fed to the die in the disk, and which does 
 the further duty of one-half of the shears for the cutting off the wire or rod, the die itself being the other 
 half of said shears. The rods or wire may be fed in by hand, or by any convenient machinery, in many 
 ways, such apparatus being common to machines for these purposes. 
 
 The operation of my machine will be better understood by saying that the machinery is set in motion 
 by power applied at the pulley s. We commence feeding wire or rods through the tube into the 
 dies, while the disk is at rest ; next, the disk of dies move round (always in the same direction) and 
 cut off the wire, which has been fed in until it meets the herein-before-named gage v. This revolving 
 action brings a second die which is also fed in, and so on until each die will be filled as intended. As 
 the dies continue to fill and cut off, they pass on, and one after the other meets tire header and subse- 
 quently the discharger, wheli one after the other is discharged — all the other operations being performed 
 in the progress, and between the feeding and discharging. 
 
 RIVETING AND STEAM PUNCHING MACHINE. By M. Leiiattre, Paris. The principle on 
 which the motive power of the steam-engine is applied in the machine now before us, is widely different 
 from that which characterizes most of those of which we have yet treated, and, simple and obvious as it 
 may appear, it is only beginning to be appreciated by mechanicians as we think it deserves. 
 
 In those machines in which a rectilinear motion, whether in a horizontal or vertical direction, is re- 
 quired to be produced, that object has hitherto, in most cases, been accomplished by n.eans of mechan- 
 ism, more or less complicated and expensive, for converting the rotary motion transmitted through long 
 trains of shafts from the fly-wheel of a steam-engine, into a rectilinear motion. In establishments in 
 which a great number of machines, small as well as great, have to be kept in motion, we believe that 
 no improvement upon this roundabout method could be recommended ; but for single and independent 
 machines, where great power acting in a rectilinear direction is required, we believe that the direct 
 action of the steam-engine, as exemplified in the machine now to be described, will supersede the more 
 rircuitous, expensive, and, on many accounts, objectionable method hitherto practised. 
 
 Another very important peculiarity in the machine now under consideration, deserves to he specially 
 
 3 ’ 19 . 
 
RIVETING MACHINE. 
 
 573 
 
 noticed. In riveting by hand the workman finds it. necessary to bring the plates upon which he is opera 
 ting into close contact, by striking them with his hammer while closing and finishing the head of the 
 rivet. The necessity of this will be obvious when we consider that the iron pin, which is to form the 
 rivet, tends, by the compression to which it is subjected by the blows of the hammer, to stave up through- 
 out its whole length, as well as at the end, and that, consequently, unless the plates are brought into 
 very close contact during the operation, an obstacle to their perfect junction is interposed by the very 
 means employed to bring them into intimate contact. In M. Lemaitre’s machine this difficulty is obvi- 
 ated by a very ingenious and effective contrivance which we shall now proceed to describe. 
 
 Fig. 3220 is an elevation. Fig. 3221 a plan. Fig. 3222 an end view, and Fig. 3223 a partial section 
 of the steam punching and riveting machine. 
 
 The plates to be operated upon are, in this machine, placed horizontallv between the fixed and mov 
 able dies a and b. The matrix of the fixed die a is at the extremity of a strong malleable-iron stem or 
 riveting-block A, fixed firmly into the sole and foundation of the machine, anti serving as the point o{ 
 resistance against the action of the punch l , the compressing ferule i, and the riveting-die b. This last, 
 which, as well as its corresponding fixed die a, is made of hard-tempered steel, is fixed into a malleable 
 iron stock or tool-holder B, accurately planed and adjusted to slide in a vertical direction, and without 
 lateral motion, in a socket G, the further purpose of which will hereafter be described. The tool-holder 
 B has an alternate rectilinear motion of ascent and descent communicated to it by a malleable-iron lever 
 C, which has its centre of oscillation at tire upper extremity of a strong frame D, cast in a piece with 
 the sole or base by which the machine is fixed to its foundations. The opposite end of the lever C is 
 connected by the rod E, to a piston working in the cylinder F. This cylinder, which is open above, and 
 close beneath the piston, is furnished with a valve inclosed in the vaive-box c, and by this valve high- 
 pressure steam is alternately admitted under the piston, through the steam-pipe g, and allowed to es- 
 
 cape through the exhaust-pipe h. The valve is raised or depressed by means of the combination oi 
 rods and levers def, which are disposed so as to place the machine within the command of the work- 
 man who superintends the operation. The mechanism by which the plates are compressed during the 
 process of riveting consists of a cylindrical steel ferule i, Fig. 3223, through the centre of which the riv- 
 eting-die b passes, and which again is fitted into a strong cast-iron socket G, sliding exactly and without 
 play, between two planed guides H H. The socket G is made hollow for the purpose of forming the 
 guide to the tool-holder B, as we have already mentioned, and receives a motion similar to, though in- 
 dependent of, the latter, from the two malleable-iron levers 1 1, which have their centre of oscillation at 
 the same point as the lever 0, and are connected at their opposite extremities by the rod J to a piston 
 contained within the cylinder K. This latter cylinder is of smaller diameter than that used for riveting 
 and like it, is provided with a valve c for the admission and escape of steam. The rods and levers d, 
 e /', for opening and shutting this valve, are arranged in the same way as those already described. 
 
 This machine is adapted for punching as well as riveting iron plates. For this purpose two strong 
 parallel guides M M are fixed to the movable frame which carries the compressing ferule*. To the 
 centre of these guides a socket or tool-holder L is attached by means of a pin m passing through its 
 upper extremity and the guides. The punch l is fitted to the opposite end of the socket L, and its po- 
 
574 
 
 RIVETING MACHINE. 
 
 sition, when brought into operation by turning it downwards upon its pivot m and securing it between 
 the guides M M, coincides exactly with that of the matrix a', upon the extremity of the riveting-block A 
 The matrix a! is sunk into a circular recess cast upon the riveting-block, and for the sake of accurate 
 adjustment, is acted upon by three small screws passing through the sides of the recess. Under these 
 circumstances, it is obvious that the operation of punching will be performed by the same mechanism, 
 by which, in riveting, the compressing ferule is made to descend. When not required to be used, the 
 punch and its socket are turned into the position represented in Figs. 3222 and 3223. 
 
 Action of the machine . — The plates to be united by riveting, having been previously punched, are 
 placed together, as shown in the drawings, upon the horizontal stem or riveting-block A. The heated 
 rivet is then placed into its appropriate hole, with the head inside, and the plates are shifted till the 
 rivet-head falls into the matrix a. The attendant workman by pulling down the handle/' depresses the 
 valve inclosed in the steam-chest c, and thus opens a communication through the pipe g, between the 
 steam in the boiler and the under side of the piston working in the cylinder K. The piston ascends, and 
 its motion being communicated through the rod J to the level's 1 1, causes the ferule i to descend, and 
 compress the plates firmly together. The same workman then, by pulling down the handle/, opens 
 the valve of the large cylinder F, taking care that the pressure is still kept upon the plates. This 
 causes the tool-holder B, and riveting-die b, to descend, and thus the rivet is finished. The valve of the 
 cylinder F is then first moved so as to shut the communication between the boiler and the piston, and 
 allow the steam to escape through the pipe li. The weight of the rod E and lever C causes the piston 
 to descend and the die b to rise. The handle f is then released, and by a similar process the ferule i 
 rises to admit of the plates being shifted for the fixing of the next rivet. 
 
 The action of the machine in punching is obviously so similar to that already explained as to require 
 no further description. As it is of importance that the rivet-holes should be pierced with as little delay 
 as possible, at the same distance from each other, and in the same line, M. Lemaitre makes use of a 
 marker which serves as a guide to the workman in placing the plates under the action of the machine. 
 This contrivance consists of a small arm n formed into a socket, so as to admit of being adjusted and 
 fixed upon the axis o, which has its bearings in one of the cheeks or guides M. Into the arm n is fixed 
 a small piece of sheet-iron, shaped at the outer extremity into a circle, the diameter of which is equal to 
 that of the punch, and its centre, when turned towards the punch, coinciding with it. In making use of 
 this contrivance the handle p of the axis o is turned round till the extremity of the arm n is brought 
 directly under the punch. The plates are then shifted so that the place where the hole is to be pierced 
 is covered by the circular end of the sheet-iron marker, and thus the accuracy of the work is insured. 
 
 Figs. 3224 and 3225 represent a very ingenious and most useful contrivance which M. Lemaitre has 
 adapted to this machine, for the purpose of riveting long and narrow tubes from the interior, a problem 
 which, at first sight, is of very difficult solution. The stem or riveting-block N is made hollow through 
 out its whole length, and incloses a long rod S, terminated by a steel wedge r. This wedge acts upon 
 the movable matrix t, which passes through the upper side of the riveting-block A, in such a way as to 
 cause it to rise or fall according as the rod S is pushed in or drawn out. The die u and its holder or 
 stock O are of the same form, and are connected with the machine in the same manner as those already 
 described. In using this form of the machine, the rivets are inserted from the outside of the tube, the 
 dies t and u receive simultaneously a motion in opposite directions, the lower one t being made to rise 
 by pushing in the rod S, and the upper one u descending by the action of the steam-piston upon the 
 lever, and thus the rivet is formed. 
 
 M. Lemaitre has been enabled, by this contrivance, to rivet tubes of considerable length and small 
 diameter ; a work which it was impossible to perform either by hand or by any machine formerly in 
 existence. 
 
 Literal References. 
 
 A, the malleable-iron stem or riveting-block. 
 
 B, the stock or tool-holder into which is fixed the riveting-die 6, and which is made to move in a ver- 
 tical direction by the great lever 
 
 C, by which the pressure necessary for forming the rivet-head is conveyed from the steam-piston. 
 
 I), the frame and sole or base of the machine. 
 
 E, the connecting-rod between the piston inclosed within the cylinder F and the lever C. 
 
 F, the steam-cylinder in which the power required for forming the rivet-head is generated. 
 
 G, a socket or tool-holder, to the lower end of which is fixed the compressing ferule i, and which 
 moves vertically between the two planed guides 
 
 H H, bolted firmly to the fixed frame of the machine. 
 
 1 1, a double malleable-iron lever, by which the pressure necessary for keeping the plates firmly to 
 gether is conveyed from the piston inclosed within the cylinder K, to the compressing ferule i. 
 
 J, the connecting-rod between the piston inclosed within the cylinder K and the lever I. 
 
 K, the steam-cylinder in which the power required for compressing the plates is generated. 
 
 L, the stock or socket into which the punch l is fitted. 
 
 M M, the guides for confining the tool-holder L, laterally. 
 
 a, the matrix or die on the end of the riveting-block. 
 
 a , the matrix of the punching-tool, 
 
 b, the cylindrical stock into which the riveting-die is fixed, and which works up through the compres 
 «ing ferule i. 
 
 c, the valve-box fixed to the lower extremity of the steam-cylinder F. 
 
 c, a similar valve-box fixed to the lower extremity of the cylinder K. 
 
 d ef rods and levers for working the valve attached to the cylinder F 
 
 d'ef, similar rods and levers for working the valve attached to the cylinder K. 
 
 ci h, pipes for the admission and escape of steam into and from the valve-box c. 
 
RIVETING MACHINE. 
 
 575 
 
 g’ It, pipes for the admission and escape of steam into and from the valve-box c\ 
 
 i, the compressing ferule. 
 
 k, a strengthening piece by which the foundations, frame, and riveting-block are held together. 
 
 !> the puncking-tool. 
 
 m, a joint by which the punch-holder L may be turned upwards or downwards, as required. 
 
 n, a small sheet-iron arm which may be used as a marker. 
 
 o, the axis upon which this marker is fixed. 
 
 p , a handle by which it may be turned out or in as required, 
 
 N, the hollow riveting-block used for riveting tubes internally. 
 
 O, the stock or die-holder used in the same operation. 
 
 S, a long rod terminated in a wedge r, by which the riveting-die t is made to ascend. 
 
 r, a steel wedge moving in the interior of the riveting-block N. 
 
 t, the internal riveting-die moving upwards and downwards by the action of the wedge r. 
 
 u, the external riveting-die moving upwards and downwards by the action of the steam. 
 
 Ill VET [MG MACHINE — By William Fairbairn & Co., Manchester. In the manufacture of steam- 
 engine boilers, however varied and important the improvements which have, from time to time, been 
 effected in the form and arrangement of then - parts, no attempt has, until a very recent period, beer 
 made to facilitate the means of their construction, or, by the introduction of machinery, to supersede 
 the necessity for manual labor. It is true, the punching and shearing machine has, under various mod 
 ifications, been long in use, but it is only within the last few years that machines for bending plates, 
 for making rivets, and still more recently for riveting, have been introduced. 
 
 For this last purpose, a variety of ingenious and effective combinations have been proposed, and al- 
 though, as yet, none of them has come into very general use among boiler-makers, there can be little 
 doubt that the laborious and expensi ve process of riveting by hand will be superseded by some form of 
 this machine. The first idea of the riveting machine is due to Mr. Fairbairn, of Manchester, who, in 
 1838, patented a machine in many respects similar to the common punching machine, but having the 
 great lever of such a form as to communicate a horizontal motion to the dies or tool for forming the 
 head of the rivet. The machine represented is a modification which Mr. Fairbairn has since made, 
 in which he has introduced several improvements, and remedied several defects to which the former 
 was subject. 
 
 The principle of Mr. Fairbairn’s machine consists in its performing by almost instantaneous pressure, 
 what could formerly only be done by a long series of impacts. Every mechanic is aware that the oper- 
 ation of riveting, in all ordinary cases, requires the services of three men, one to hold a hammer or other 
 mass of iron inside the boiler, against the head of the rivet, while the other two beat the protruding end 
 into the conical form given to the rivet on the outside of the boiler. For this operation very expert and 
 skilful workmen are required, that the rivets may be fixed soundly and firmly without injury to the 
 plates, and that all unnecessary hammering, which has only the effect of weakening the rivets, may be 
 avoided. By means of the riveting machine, the process is accomplished with much greater rapidity 
 and regularity, without producing the stunning and disagreeable noise unavoidable in hand riveting. 
 Besides these advantages, the operation being, as we have before said, performed almost instantane- 
 ously by the machine, the danger of injuring the rivets by hammering them when too cold is avoided 
 and the hemispherical, which we think greatly preferable to the conical form, is more easily impressed 
 upon them. 
 
 Fig. 3127 represents an elevation, and Fig. 3126 a plan of Mr. Fairbairn’s machine in its most im- 
 proved form, and as it is now constructed by him. It possesses the advantage over his first proposed 
 torm, of being more compact and portable, and is capable of more extensive application, being adapted 
 to rivet angle-iron, and finish the corners of boilers and cisterns. 
 
 The sole or base of the machine A is made of cast-iron, and mounted upon wheels adapted to rails, 
 .or the convenience of shifting it to any required place. The framing B B is cast in a piece with the 
 
576 
 
 RIVETING MACHINERY. 
 
 sole A, and consists of an oblong box, open at the top, and furnished with bearings for the movable 
 parts of the machine ; C, a strong upright stem of malleable iron, fitted firmly into the base A, which 
 is secured against the effect of undue strains, arising from the dies coming in contact with a cold rivet 
 or other hard substance, by a malleable-iron strap D passing round its upper edge, and secured by nuts 
 at a a. The stem or riveting-block G is the point of resistance to the action of the dies, and against it is 
 placed that part of the boiler which is to undergo the process of riveting. It is made of malleable-iron, 
 in order that it may possess a certain amount of elasticity, which is necessary to the prevention of such 
 accidents as we have just alluded to. Its upper extremity is formed into an oblong block k, and in this 
 the matrices for receiving the dies are placed. - 
 
 The moving parts of the machine consist of a shaft carrying the fast and loose pulleys E and F, 
 driven by the belt b. To give the requisite power and velocity to the machine, a pinion G is fixed 
 upon this shaft, and works into a wheel I, keyed upon another and stronger shaft situated directly over 
 the former. On the pinion-shaft is placed the fly-wheel H, for giving a uniform motion to the working 
 parts of the machine, and at each revolution of the wheel I the machine performs one stroke. The 
 ratio of the pinion G to the wheel I is as 1 to 6 ; consequently, when the pulleys are driven at the rate 
 of 42 revolutions per minute, the machine performs 7 strokes per minute, and this is found to be the 
 most suitable velocity. On the axis of the wheel I is fixed a cam c, of the form denoted by the dotted 
 lines in Fig. 3127. This cam, in its revolution, alternately raises and suffers to fall by its own weight 
 the friction-pulley d, which runs loose upon the centre pivot of a knee-joint composed of the arms e e 
 and ff. The arms ee working upon a fixed centre, as shown in the plan, the elevation of the pulley d 
 by the cone c necessarily impresses a horizontal motion upon the corresponding extremities of the arms 
 //'. These extremities are connected by a joint to the slide g, the motion of which is guided into a per- 
 fectly rectilinear and horizontal direction by the dovetail pieces h h, planed true and screwed firmly to 
 the frame of the machine. The sliding piece g is furnished at its outer extremity with three holes or 
 matrices for receiving the die i, which forms the head of the rivet. These matrices are so placed that 
 their centres coincide exactly, both in the horizontal and vertical planes, with the centres of similar ones 
 in the upper extremity of the stem or riveting-block c, already described. Into these latter is fitted the 
 die?', against which the head of the rivet is placed during the process. The centre matrix in which the 
 dies are represented in the figure is used for riveting every description of flat or circular work, while 
 those at each side are required for finishing the corners of the boilers.. Thus the machine is adapted 
 for riveting vessels of almost every shape within the given depth. 
 
 Action of the machine . — The plates to be riveted together, having been previously punched in the 
 usual way, are suspended by a block and chain, as shown in Fig. 3127. The heated rivet is then in- 
 serted into its appropriate hole, and the attendant workman shifts the plates, so that the head of the 
 rivet falls into the recess on the point of the diey. The machine is then put in motion by changing the 
 position of the strap b from the loose to the fixed pulley. This motion is transmitted by the mechanisn 
 above described, to the sliding tool-holder g, and its projecting-die i, in its advance, forms the head and 
 finishes the rivet. The velocity of the machine is so calculated as to allow time between each stroke 
 for the insertion of another rivet and the readjustment of the plates, and thus the work proceeds with- 
 out interruption. 
 
 It is stated by Mr. Fairbairn that, with two men and two boys attending to the plates and rivets, his 
 machine can fix, in the firmest manner, eight rivets of three-quarters of an inch diameter in a minute, 
 whereas, by the common process of hand riveting, three men and a boy can only rivet up 40 per hour. 
 Thus the quantity of work done in the same time in the two cases is in the proportion of 480 to 40, or 
 as 12 to 1, exclusive of the saving of one man’s labor. 
 
 RIVETING MACHINERY— GARFORTH’S PATENT, for riveting metallic plates, for the con- 
 struction of boilers, and other purposes. 
 
 These improvements in machinery or apparatus for connecting metallic plates for the construction 
 of boilers, consist in the direct application of the expansive force of steam to the dies for riveting 
 such plates together, and in an arrangement of machinery whereby such force is brought into 
 action. 
 
 3228. 3229. 
 
 Fig. 3228 represents a plan or horizontal view of an arrangement of machinery or apparatus designed 
 for connecting or riveting metallic plates for the construction of steam-boilers ; Fig. 3329 is a side view ; 
 and Fig. 3230 a section, taken longitudinally through about the centre of the apparatus, a a is the 
 
ROLLING MACHINE. 
 
 577 
 
 frame-work for supporting the steam-cylinder b b, in ■which a steam-tight metallic or other piston c « 
 works ; this piston c c is mounted upon the rod dd which passes out through stuffing-boxes e e at each 
 end of the cylinder b b; in the end a* of the piston-rod the die /is fixed, the other die g being mounted 
 in the pillar h, which is fast to the frame-work. Steam being admitted through the entrance or feed- 
 pipe i, it passes onwards through a common slide or other valve k, to the cylinder ; and after having 
 performed its office, is allowed to pass out through 'the pipe l. The slide-valve k is worked by hand, 
 by means of the lever m, so as to admit the steam on either side of the piston as required. 
 
 The operation of the apparatus is as follows : Steam of a sufficient pressure being admitted (by 
 means of the slide-valve k) at the back, or as it appears in Fig. 3230 at the left-hand side of the piston 
 cc, that piston will be forced, together with the piston-rod dd*, in the direction of the arrow, and form 
 the ends of the rivet n, between the two dies/ and 17 ; thus firmly connecting the plates 0 and p, and 
 thereby producing a perfectly steam, air, or water tight joint. 
 
 The head of the rivet is formed at one or more blows, as required; the intensity of the blow depend- 
 ing upon the area of the piston, the length of the stroke, and the pressure of the steam employed. The 
 valve k is then reversed, to admit the steam in front of the cylinder ; which movement will withdraw 
 the die/, when another rivet may be put in, and the operation proceeds as before. 
 
 The patentee remarks that he does not intend to confine himself to the use of steam alone for such 
 purposes, as the direct pressure of water, air, or other elastic medium may be similarly employed, 
 without departing from the principle of his invention. He states that he does not claim the exclusive 
 use of the several parts of the above-mentioned apparatus, when taken separately, but only when em- 
 ployed for the purpose of his invention, which consists in the riveting of metallic plates by dies driven 
 by the power of steam, water, &c. 
 
 3231. 
 
 ROLLING MACHINE, for rolling iron, specially intended for railroad bars and locomotive tires a 
 
 new method, invented by Horatio Ames, of Falls Village, Connecticut. 
 
 We are induced to publish the entire specification and drawings of this invention, not only on account 
 of the value and merit which it presents, but because of the deep interest which must be felt in all such 
 improvements by those who are engaged in the manufacture of iron, and in railroads. The great rival- 
 ship now going on in this country and in England, in the manufacture of iron, renders every improve- 
 ment which looks either to the reduction of the cost of manufacture, or to the amelioration of the quality 
 of the iion, of the highest importance. And as the cost of repairs on railroads arises in a great measure 
 fiom the wear of railroad bars and locomotive tires, by exfoliation and splitting, any invention which 
 pi onuses to avoid this evil must be looked upon with interest. The invention in question has already 
 excited a deep interest in England, where the inventor has secured it by patent. 
 
 Fig. 3-31 is a plan of the machine; Fig. 3232, a side elevation; Fig. 3233, a longitudinal vertical 
 section taken at the line X X of Fig. 3231 ; and Fig. 3234, a like section, taken at the line ZZ of the 
 same figure. The same letters indicate like parts in all the figures. 
 
 In the manufacture of iron, either by rolling or hammering, the fibres are all drawn longitudinally, 
 which, foi the rails of railroads, for the tires of railroad wheels, and for a variety of other purposes, 
 renders it liable to break off in thin leaves or scales, or to split lengthwise — this state of things bein°- 
 very common in the two instances specified. The object of my invention is so to treat the iron, either 
 m the original manufacture thereof, or afterwards, as to avoid this defect, and thereby render the iron 
 tor these purposes more durable, by laying the fibres in such form and direction as to prevent it from 
 scaling off or splitting. And my invention consists in twisting the iron in, or before, or after, the opera- 
 lion ot 10 ing 01 hammering, so that the fibres shall wind around one another, in a manner somewhat 
 similar to the fibres of hemp in a twisted rope or strand. 
 
 . Aud tl> e second part of my invention relates to the machinery by which I carry into effect my 
 improved process, and consists in combining two or more sets of rollers, one or both of which are to be 
 iaw 10 er^ and one set turning in the usual permanent bearings, and the other set or sets working in 
 a frame or chuck that rotates on an axis at right angles to the axis of the rollers, to twist the bar oi 
 iron between the two sets of rollers. 
 
 Vol. II. — 37 
 
578 
 
 ROLLING MACHINE. 
 
 To enable any one skilled in the art to apply my improved process of treating iron, and to construct 
 and use the machine which I have invented therefor, I will describe the mode of procedure which I 
 have essayed, as well as the manner of constructing and raising the machine therefor. The bloom of 
 iron, or a bar previously formed, is taken while in a heated state, and twisted while undergoing the 
 operation of hammering, which may be done by securing one end of the bloom or bar in a clamp and 
 rotating it while the hammer rests on the other end ; or by securing the two ends in separate clamps 
 and twisting one of them, or both, in opposite directions, until the required twist has been given, and 
 then subjecting it to the operation of hammering. But when the bar is to be drawn by rolling, the bar 
 is to undergo the operation of twisting while passing between the rollers, or after it has passed between 
 one set, and before it passes between the second set; and when it is twisted on its way to the rollers, 
 one end of the bar may be secured to a clamp, which is to be rotated as the bar passes between the 
 draw-rollers. 
 
 3232. 
 
 As the bars thus prepared are, in most instances, to be reworked to receive the required form or 
 forms, according to the purposes which they are to be applied to, it will be evident that they may be 
 twisted as they pass from the hammer or the rollers, instead of giving the twist before the hammering 
 or rolling ; and to effect this, the end of the bar may be clamped as it leaves the hammer or rollers, and 
 the required twist given ; but it is better to give the twist before the iron has undergone the operation 
 of rolling or hammering, as it is then more highly heated, and the fibres will not be so severely strained 
 as they would be after the metal has been partly cooled. 
 
 When iron has been treated and worked according to this process, the fibres, instead of running in the 
 bar longitudinally, in straight lines, will run in the direction of a helix, gradually approaching to a 
 straight line from the circumference to the axis of the bar, so that when used for making tires, or for 
 other analogous purposes, the bar will be prevented from splitting along its length by the tenacity of 
 tire fibres, which cross the bar in the direction of a helix, instead of the mere adhesion of the fibres 
 together ; and when used for the rails of railroads, or similar purposes, none of the fibres can be sepa- 
 rated from the mass longitudinally, as heretofore, nor can the iron be stripped off in scales until they 
 have been cut off on each side, for, by their direction, they pass diagonally from one side, over the sur- 
 face, and down the other side, whereby they are completely tied together. 
 
 3233. 
 
 Of the machinery for working iron in accordance with the foregoing process . — In the accompanying 
 drawings a represents a frame properly adapted to the purpose, and h h two grooved rollers, such as are 
 used in rolling-mills for rolling bars of iron — the groove in each being semicircular, or nearly so, that 
 the two together may form a cylindrical bar. These two rollers are placed one above the other, with 
 their journals in appropriate boxes in the two standards c c. The shaft of the lower roller extends out 
 beyond one of the standards, and is provided with a level cog-wheel d, which mashes into a level 
 pinion e on the main driving-shaft/, which turns the lower roller to feed in the bar of iron g — the upper 
 roller being carried by the motion of the lower one. Just back of the first set of rollers above described, 
 there is another pair nn, similar to the first, except that the grooves in them are smaller, to draw the 
 iron slightly, after passing the first set — they are mounted in a hollow chuck or frame i on the forward 
 end of a hollow shaft or mandrel j that has its bearings in two standards k k, and which is provided 
 with a cogged pinion l, the teeth of which engage with a cog-wheel m on the main-shaft, by which the 
 second set of rollers are made to rotate at right angles to their axes, and on an imaginary line passing 
 through the bight of the two sets of rollers, and in the centre of the two holes formed by the grooves 
 ui the rollers at the bight of each set, the axis of the hollow shaft or mandrel being in this imaginary 
 
ROPES, STIFFNESS OF. 
 
 579 
 
 line. Back of the clutch, and attached to the front face of the forward standard k, there is a wheel n , 
 the cogs of which mash into the cogs of two pinions o o on two short arbors pp , one on each of the two 
 opposite sides of the chuck, the other end of these short arbors being provided each with a short screw q, 
 the threads of which engage with the cogs of two pinions r r, one on the end of each of the rollers of 
 the second set, so that the cog-wheel n, being permanently attached to the standard when the hollow 
 shaft with its chuck, and the second set of rollers, is turned, the two cogged pinions o o travel about this 
 wheel, which turns the arbors to which they are attached, in the direction of the reverse of the rotation 
 of the chuck, and the threads of the screw in turn engaging with the cogs of the pinions on the shafts 
 of the second set of rollers causes these to rotate on their axes, and in the same direction with the first 
 set, and with a velocity, relatively to the rotation of the first set, proportioned to the amount of drawing 
 action which they are intended to exert on the bar that is to pass between. 
 
 In this way it will be obvious that when the machine is put in motion, and a bar of iron fed in, it will 
 pass between the first pair of rollers and be partly drawn, and then pass between the second pair, 
 which having two motions, one on their axis and another at right angles thereto, and on the axis of 
 tfc« bar of iron, it (the bar) will in consequence be twisted between the two pairs of rollers, and also 
 d; awu by them, and the fibres compressed. 
 
 3235. 
 
 From the foregoing it will be obvious that the extent of drawing action of either or both sets of 
 Ira wing-rollers can be regulated at pleasure, by simply varying the size of the grooves and relative 
 motions of the draw-rollers on their axes, and their rotation on the axis of the bar of iron. 
 
 It will be equally obvious that the number of draw-rollers can be increased -without changing the 
 principle of my invention. It is to be understood that the iron, when subjected to the compound action 
 of drawing and twisting, is to be in a heated state, such as practised by and known to iron-masters in 
 the manufacture of iron. 
 
 Claim . — What I claim as my invention is, first, the method herein described of treating iron to 
 increase its toughness or durability for certain purposes — such as railroad bars and tires, &c . — by sub- 
 jecting it, in a highly heated state, to the compound operation of drawing and twisting, substantially as 
 herein described. 
 
 I also claim in the machinery above described, giving to one set of rollers the rotary motion on their 
 axes, and a rotary motion at right angles thereto, on the axis of the bar of iron, when this is combined 
 with another pair of rollers that have simply a rotary motion on their axes, whereby the bar of iron, in 
 a highly heated state, is drawn and twisted. 
 
 HOPES, STIFFNESS OF, or the resistance of ropes to bending upon a circular arc. The experi- 
 ments upon which the rules and table following are founded were made by Coulomb, with an appara- 
 tus the invention of Amonton, and Coulomb himself deduced from them the following results : 
 
 1. That the resistance to bending could be represented by an expression consisting of two terms, the 
 one constant for each rope and each roller, which we shall designate by the letter A, and which this 
 philosopher named the natural stiffness, because it depends on the mode of fabrication of the rope, and 
 the degree of tension of its yarns and strands ; the other, proportional to the tension, T, of the end of 
 the rope which is being bent, and which is expressed by the product BT, in which B is also a number 
 constant for each rope and each roller. 
 
 2. That the resistance to bending varied inversely as the diameter of the roller. 
 
 Thus the complete resistance is represented by the expression 
 
 A+ BT. 
 
 D 
 
 where D represents the diameter of the roller. 
 
 Coulomb supposed that for tarred ropes the stiffness was proportional to the number of yarns, and 
 M. Navier inferred, from examination of Coulomb’s experiments, that the coefficients A and B were 
 proportional to a certain power of the diameter, which depended on the extent to which the cords were 
 worn. M. Morin, however, deems this hypothesis inadmissible, and the following is an extract from his 
 new work, “ Leqons de Mecanique Pratique” December, 1816 : 
 
 “ To extend the results of the experiments of Coulomb to ropes of different diameters from those 
 which had been experimented upon, M. Navier has allowed, very explicitly, what Coulomb had but sur- 
 mised — that the coefficients A and B were proportional to a certain power of the diameter, which depended 
 on the state of wear of the ropes ; but this supposition appears to us neither borne our, nor even admis- 
 sible, for it would lead to this consequence, that a worn rope of a metre diameter would have the same 
 stiffness as a new rope, which is evidently wrong ; and, besides, the comparison alone of the values oj 
 
580 
 
 ROPES, STIFFNESS OF. 
 
 A and B shows that the power to which the diameter should be raised would not be the same for the 
 two terms of the resistance.” 
 
 Since, then, the form proposed by M. Navier for the expression of the resistance of ropes to bending 
 cannot be admitted, it is necessary to search for another, and it appears natural to try if the factors A 
 and B cannot be expressed for white ropes, simply according to the number of yarns in the ropes, as 
 Coulomb has inferred for tarred ropes. 
 
 Now, dividing the values of A, obtained for each rope by M. Navier, by the number of yarns, we 
 find for 
 
 A 
 
 n = 30 <1= 0“-200 A = 0-222460 - = 0-0074153 
 
 n 
 
 n = 15 d= 0 m -144 A = 0'003514 — = 0'0042343 
 
 ii 
 
 n— 6 d=Q m ' 0088 A = 0-010604 - = 0D017673 
 
 n 
 
 It is seen from this that the number A 's not simply proportional to the number of yams. 
 
 Comparing, then, the values of the r» do — > corresponding to the three ropes, we find the following 
 results : 
 
 Number of 
 yarns. 
 
 Values of ^ • 
 
 7 , 
 
 Diffe.ences of the numbers 
 of yarns. 
 
 Differences of 
 the values of 
 A 
 n 
 
 Differences of 
 the values of 
 
 — for each yarn 
 n 
 
 of difference. 
 
 30 
 
 0-0074153 
 
 From 30 to 15. 
 
 15 yarns 
 
 0-0031810 
 
 0-000212 
 
 15 
 
 0-f 04234 'J 
 
 “ 15 to 6. 
 
 9 “ 
 
 00024770 
 
 0-000272 
 
 6 
 
 'VOOR, 673 
 
 “ 30 to 6. 
 
 24 “ 
 
 0-0056400 
 
 0-000252 
 
 Mean difference per yarn, 0-000245. 
 
 It follows, from the above, that the values of A, given by the experiments, will be represented with 
 sufficient exactness for all practical purposes by the formula 
 
 A = n [0-0017673 + 0-000245 (n — 6)]. 
 
 = n [0-0002973 + 0-000245 «]. 
 
 An expression relating only to dry white ropes, such as were used by Coulomb in his experiments. 
 With regard to the number B, it appears to be proportional to the number of yarns, for we find for 
 
 5i = 30 d = 0 m -0200 B = 0-009738 - = 0-0003246 
 
 n 
 
 n= 15 cl = 0 m -0U4 B = 0-005518 - = 0-0003678 
 
 n 
 
 Whence 
 
 51 = 6 (f=0m-0088 B = 0-002380 — = 0-0003967 
 
 n 
 
 Mean 0-0003630 
 
 B = 0-000363 n. 
 
 Consequently, the results of the experiments of Coulomb on dry white ropes will be represented 
 with sufficient exactness for practical purposes by the formula 
 
 K = « [0-000297 + 0-000215 n + 0-000363 T] kil. 
 
 -which will give the resistance to bending upon a drum of a metre in diameter, or by the formula 
 
 R = ~ [0-000297 + 0-000245 n + 0-000363 T] kil. 
 tor a drum of diameter D metres. 
 
 These formulae, transformed into the Englfeh scale of weights and measures, become 
 R = k [0-0021508 + 0-0017724 n + 0-0011909S T] lbs. 
 for a drum of a foot in diameter, and 
 
 R = ^ [0-0021508 + 0-0017724 n + 0-00119096 T] lbs. 
 for a drum of diameter D feet. 
 
 With respect to worn ropes, the rule given by M. Navier cannot be admitted, as I have shown above 
 
ROPES, STIFFNESS OF. 
 
 581 
 
 Decause it would give for the stiffness of a rope of a diameter equal to unity the same stiffness as for a 
 new rope ; and it is from having adopted, with other authors, this rule without investigation, that I have 
 been led to this inadmissible result, in calculating the table of the stiffness of ropes inserted in the third 
 edition of my Aide Memoire de Mecanique Pratique , p. 328. 
 
 The experiments of Coulomb on worn ropes not being sufficiently complete, and not furnishing any 
 precise data, it is not possible, without new researches, to give a rule for calculating the stiffness of 
 these ropes. 
 
 Tarred ropes . — In reducing the results of the experiments of Coulomb on tarred ropes, as we have 
 done for white ropes, we find the following values : 
 
 n = 30 yarns A = 0-34982 B = 0-0125605 
 n — 15 “ A = 0-106003 B = 0-006037 
 
 n— 6 “ A = 0-0212012 B = 0-0025997 
 
 which differ very slightly from those which M. Navier has given. But, if we look for the resistance 
 corresponding to each yarn, we find 
 
 A B 
 
 n = 30 yarns — = 0'0116603 - = 0-000418683 
 
 n n 
 
 _ A _ B 
 n = 15 “ - =0-0070662 - = 0-000402466 
 
 n n 
 
 A B 
 
 n= 6 “ - =0-0035335 - =0-000433283 
 
 n n 
 
 Mean 0-000418144 
 
 We see by this that the value of B is for tarred ropes, as for white ropes, sensibly proportional to the 
 number of yarns, but it is not so for that of A, as M. Havier has supposed. 
 
 Comparing, as we have done for white ropes, the values of — corresponding to the three ropes of 30, 
 15, and 6 yarns, we obtain the following results : 
 
 Number of 
 yarns. 
 
 Values of — • 
 n 
 
 Differences of the numbers 
 of yarns. 
 
 Differences of 
 the values of 
 A 
 n 
 
 Differences of 
 the values of 
 
 — for each yarn 
 n 
 
 of difference. 
 
 30 
 
 0-0116603 
 
 From 30 to 15. 
 
 15 yarns 
 
 0-0045941 
 
 0-000306 
 
 15 
 
 0-0070662 
 
 “ 15 to 6. 
 
 9 “ 
 
 0-0035327 
 
 0-000392 
 
 6 
 
 0-0036335 
 
 * 30 to 6. 
 
 25 “ 
 
 0-0081268 
 
 0000339 
 
 Mean 0-000346 
 
 It follows from this that the value of A can be represented by the formula 
 
 A = n [0-0035335 + 0'000346 (n — 6)] 
 
 = n [0-0014575 -F 0-000346 n] 
 
 and the whole resistance on a roller of diameter D metres, by 
 
 R = g [0-0014575 + 0-000346 n + 0-000418144 T] kil. 
 
 Transforming this expression to the English scale of weights and measures, we have 
 R = g [0-01054412 -h 0-00250309 n + 0-001371889 T] lbs. 
 for the resistance on a roller of diameter D feet. 
 
 This expression is exactly of the same form as that which relates to white ropes, and shows that the 
 stiffness of tarred ropes is a little greater than that of new white ropes. 
 
 In the following table the diameters corresponding to the different numbers of yarns are calculated 
 from the data of Coulomb, by the formulae 
 
 d cenl - = V 0-1338 n for dry white ropes, and 
 d ce " t - = V O'l 86 n for tarred ropes, 
 which, reduced to the English scale, become 
 
 d inches \f 0-020739 n for dry white ropes, and 
 d in ' hcs = V 0-028S3 for tarred ropes. 
 
 A nte . — The diameter of the rope is to be included in D ; thus, with an inch rope passing round a pul 
 ley, 8 inches in diameter in the groove, the diameter of the roller is to be considered as 9 inches. 
 
582 
 
 SAWS. 
 
 i 
 
 Ery White Ropes. 
 
 Tarred P»opes. 
 
 Number of 
 
 Diameter. 
 
 Value of the natural 
 stiffness, A. 
 
 Value of the stiff- 
 ness proportional 
 to the tension, B. 
 
 Diameter. 
 
 Value of the natural 
 stiffness, A. 
 
 Valueofthestiff- 
 ness proportional 
 to the tension, li. 
 
 | 
 
 
 ft. 
 
 lbs. 
 
 
 ft. 
 
 lbs. 
 
 
 6 
 
 0'0293 
 
 0-0767120 
 
 0-0071457 
 
 0-0347 
 
 0-153376 
 
 0-00823133 
 
 9 
 
 00360 
 
 ■ 01629234 
 
 0-0107186 
 
 0-0425 
 
 0-297647 
 
 0-01234700 
 
 12 
 
 0-0416 
 
 0-2810384 
 
 0-0142915 
 
 0-0490 
 
 0-486976 
 
 0-01646267 
 
 15 
 
 0-0465 
 
 0-4310571 
 
 0-0178644 
 
 00548 
 
 0721357 
 
 0-02057834 
 
 18 
 
 0-0509 
 
 0 6129795 
 
 0-0214373 
 
 0-0600 
 
 0-000795 
 
 0-02469400 
 
 21 
 
 0 0550 
 
 0-8268054 
 
 0-0250102 
 
 0-0648 
 
 1-325289 
 
 0-02880967 
 
 24 
 
 0-0588 
 
 1-0725350 
 
 0-0286831 
 
 0-0693 
 
 1-694839 
 
 0-03292534 
 
 27 
 
 0-0622 
 
 1-3501682 
 
 00321559 
 
 0-0735 
 
 2-109444 
 
 0-03704100 
 
 30 
 
 0-0657 
 
 1-6597051 
 
 0-0357288 
 
 0-0775 
 
 2-569105 
 
 0'04115667 
 
 33 
 
 0-0689 
 
 2-0011455 
 
 0-0393017 
 
 0-0813 
 
 3-073821 
 
 0-04527234 
 
 36 
 
 0-0720 
 
 2-3744897 
 
 0-0428746 
 
 0-0849 
 
 3-623593 
 
 0-04938800 
 
 39 
 
 0-0749 
 
 2-7797375 
 
 0-0464475 
 
 0-0884 
 
 4-218416 
 
 0-05350367 
 
 42 
 
 0-0778 
 
 3-2168888 
 
 0-0500203 
 
 0-0917 
 
 4-858303 
 
 0-05761934 
 
 45 
 
 0-0805 
 
 3-6859438 
 
 0-0535932 
 
 00949 
 
 5-543242 
 
 0-06173501 
 
 48 
 
 0-0831 
 
 4-1869024 
 
 0-0571661 
 
 0-0980 
 
 6-273287 
 
 0-06585067 
 
 51 
 
 0-0857 
 
 4"7 197647 
 
 0-0607390 
 
 0-1010 
 
 7-048287 
 
 0-06996634 
 
 54 
 
 0-0882 
 
 5-2845306 
 
 0-0643119 
 
 0-1040 
 
 7-868393 
 
 0-07408201 
 
 57 
 
 0-0908 
 
 5-8812001 
 
 0-0678847 
 
 0-1070 
 
 8-733554 
 
 0-07819767 
 
 60 
 
 0-0926 
 
 6-5097733 
 
 0-0714576 
 
 0-1099 
 
 9-643771 
 
 0-08231334 
 
 n 
 
 v/0-000144 n 
 
 ( 0 0021508 n 
 
 \ +0.0017724 7t 2 
 
 0'00119096?i 
 
 v^0 00020 n 
 
 < 0-01054412 n 
 
 $ +0-00250309 nl 
 
 0-001371889« 
 
 Application of the preceding tables or formula . — To find the stiffness of a rope of a given diameter 
 or number of yarns, we must first obtain from the table, or by the formulae, the values of the quan- 
 t.ties A and B corresponding to these given quantities, and knowing the tension, T, of the end to bf 
 wound up, we shall have its resistance to bending on a drum of a foot in diameter by the formula 
 
 R = A + BT, 
 
 Then, dividing this quantity by the diameter of the roller or pulley round which the rope is actually 
 to be bent, we shall have the resistance to bending on this roller. 
 
 Example . — What is the stiffness of a dry white rope, in good condition, of 60 yarns, or '0928 diameter 
 which passes over a pulley of 6 inches diameter in the groove, under a tension of 1000 lbs.? The table 
 gives for a dry white rope of 60 yarns, in good condition, bent upon a drum of a foot in diameter, 
 
 A = 0-50977 B = 0'07l4576 
 
 and we have D — 0 5 + 0-0928 ; and consequently, 
 
 _ 6-50977 + 0-071457CX1000 
 — 0-5928 
 
 128 lbs. 
 
 The whole resistance to be overcome, not including the friction on the axis, is then 
 Q + K = 1000 + 128 = 1128 lbs. 
 
 Tire stiffness in this case augments the resistance by more than one-eighth of its value. 
 
 SAWS.* Saws may he considered in two groups, namely, rectilinear saws, and circular saws. The 
 blade of the rectilinear saw is usually a thin plate of sheet steel, which in the first instance is rolled of 
 equal thickness throughout : the teeth are then punched along its edge, previously to the blade being 
 hardened and tempered, after which it is smithed or hammered, so as to make the saw quite flat. The 
 blade is then ground upon a grindstone of considerable diameter, and principally crossways, so as to 
 reduce the thickness of the metal from the teeth towards the back. When, by means of the hammer, 
 the blade has been rendered of uniform tension or elasticity, the teeth are sharpened with a file, and 
 slightly bent, to the right and left alternately, in order that they may cut a groove so milch wider than 
 the general thickness, as to allow the blade to pass freely through the groove made by itself. The bend- 
 ing, or lateral dispersion of the teeth, is called the set of the saw. 
 
 The circular saw follows the same conditions as the rectilinear saw, if we conceive the right line to 
 be exchanged for the circle ; with the exception that the blade is, for the most part, of uniform thick - 
 ness throughout, unless, as in the circular veneer saws, it is thinned away on the edge. 
 
 It is to be observed that the word pitch, when employed by the saw maker, almost always designates 
 the inclination of the face of the tooth, up which the shaving ascends ; and not the interval from tooth 
 to tooth, as in wheels and screws. The teeth of some kinds are usually small, and seldom so distant as 
 an inch asunder : these are described as having 2, 3, 4, 5, to 20 points to the inch ; such as are used 
 
 Holtzapfel. 
 
SAWS. 
 
 58c 
 
 by hand, are commonly from about -J to inch asunder, and are said to be of -ir or 1^ inch space 
 although some of the circular saws are as coarse as 2 to 3 inches and upwards from tooth to tooth. 
 
 The processes denominated sharpening and setting a saw, consist, as the names imply, of two distinct 
 operations : the first being that of filing the teeth until their extremities are sharp ; the second, that of 
 bending the teeth in an equal manner, and alternately to the right and left, so that when the eye is di- 
 rected along the edge, the teeth of rectilinear saws may appear exactly in two lines, forming collec- 
 tively an edge somewhat exceeding the thickness of the blade itself. 
 
 3285. 3236. 
 
 In general the angles of the points of the saw 
 teeth are more acute, the softer the material to 
 be sawn, agreeably to common usage in cutting 
 tools ; and the angles of the points, and those at 
 which the files are applied, are necessarily the 
 same. Thus in sharpening saws for metal, the file is generally held at 90 degrees both in the horizontal 
 and vertical angle, as will be shown ; for very hard woods at from 90 to 80 degrees, ar.d for very soft 
 woods at from 70 to 60 degrees, or even more acutely. The vertical angle is about half the horizontal. 
 
 Fig. 3235 represents in plan and two elevations the saw-teeth that are the most easily sharpened, 
 namely, those of the frame-saw for metal, commonly used by the smith : the teeth of this saw are not 
 set or bent in the ordinary manner, owing to the thickness and hardness of the blade, and the small size 
 of the teeth. 
 
 The smith’s-saw blade, when dull, is 
 placed edgeways upon the jaws of the vice, 
 and the teeth which are placed upwards, 
 are slightly hammered ; this upsets or thick- 
 ens them in a minute degree, and the ham- 
 mer face reduces to a general level those 
 teeth which stand highest. They are then 
 filed with a triangular file held perfectly 
 square, or at ninety degrees to the blade, 
 both in the horizontal direction h, and the 
 vertical v, until each little facet just disap- 
 pears, so as to leave the teeth as nearly as 
 possible in a line, that each may fulfil its 
 
 share of the work. 
 
 The most minute kind of saws, those which are made of broken watch springs, have teeth that are 
 also sharpened nearly as in the diagram, but without the teeth being either upset or bent ; as in very 
 small saws the trifling burr, or rough wiry edge thrown up by the file, is a sufficient addition to the 
 thickness of the blade, and is the only set they receive. 
 
 Fig. 3236 illustrates the peg-tooth; but it may also be considered to apply to the M tooth, and, in 
 part, to the mill-saw tooth. The points of the cross-cutting saws for soft woods are required to be 
 acute or keen, that they may act as knives in dividing the fibres transversely. 
 
 The left sides of each alternate tooth, are 
 first filed with the horizontal angle denoted by 
 h, and then the opposite sides of the same teeth 
 with the reverse inclination, or li. Fig. 3237 
 may be considered to refer generally to all teeth 
 the angles of which are 60 degrees, (or the 
 same as that of the triangular file,) and that 
 are used for wood. The most common exam- 
 ple is the ordinary hand-saw tooth ; but teeth 
 of upright pitch, such as the cross-cut saw, 
 or of considerable pitch, are treated much in 
 the same manner. The teeth having been 
 topped, the faces 5, 9, are first filed back, 
 until they respectively agree with a dotted line 
 a, supposed to be drawn through the centre of each little facet produced in the topping; the file is then 
 made to take the sides 6 and t of the nook until the second half of the facet is reduced, and the point 
 of the tooth falls as nearly as may be on the dotted line a. The first course takes the face only of 
 each alternate tooth ; the second course the back of the former and face of the next tooth at one pro- 
 cess ; and the third course takes the top only of the second series, and completes the work. This ordei 
 of proceeding is employed, that the faces of the teeth may be in each case completed before the tops o. 
 backs 
 
 3233. 
 
 3237. 
 
584 
 
 SAWS. 
 
 Fig. 3238 exhibits also in three elevations a somewhat peculiar form of tooth, namely, that of the 
 pruning-saw for green wood. The blade is much thicker on the edge than the back, so that the teeth 
 are not set at all. The teeth are made with a triangular file, applied very obliquely as to horizontal 
 angle, as at h, sometimes exceeding 45 degrees, but without vertical inclination, as at v; and the faces 
 of the teeth are nearly upright, as in the hand-saw. The large sides of the teeth are very keen and each 
 vertical edge is acute like a knife, and sharply pointed ; in consequence of which it cuts the living wood 
 with a much cleaner surface, and less injury to the plant, than the common hand-saw toith. 
 
 Fig. 3239 explains the method em- 
 ployed in sharpening gullet or briar- 
 teeth ; in these there are large curvili- 
 near hollows, in the formation of which 
 the faces of the teeth also become hol- 
 lowed so as to make the projecting 
 angles acute. The gullets 3, 7, are 
 first filed, and from the file crossing the 
 tooth very obliquely, as at v v in the 
 section, the point of the tooth extends 
 around the file, and gives the curvature 
 represented in the plan. The file should 
 not be so large as the gullet ; it is there- 
 fore requisite that the file be applied in 
 twe positions, first upon the face of the 
 one tooth, and then on the back of the preceding tooth. The tops of the teeth, 2, 6, are next sharp- 
 ened with the flat side of the file, the position of which is of course determined by the angles c and d ; 
 the former varies with the material from about 5 to 40 degrees with the edge, and the latter from 80 to 
 60 degrees with the side of the blade; the first angles in each case being suitable for the hardest, and 
 the last for the softest woods. The alternate teeth having been sharpened, the remainder are completed 
 from the other side of the blade requiring in all four ranges. 
 
 After sharpening, the saw is to he set, that is, an uniform bend is given to the teeth alternately to the 
 right and to the left. This is often done by a hammer and set punch, but usually by a saw set which 
 consists of a narrow blade of steel, with notches of various widths, for different saws. The saw is 
 firmly held in clamps, the alternate teeth are inserted a little way into the proper notch, and are then 
 bent over by raising or depressing the handle of the blade. Some sets are arranged with a guide by 
 which the bends shall he uniform. 
 
 The method of sharpening and setting circular saws is very similar to that employed for rectilinear 
 saws. The teeth of circular saws are in general more distant, more inclined and more set, than those 
 of rectilinear saws. They are more distant on account of the greater velocity given to the saw, 
 whereby the teeth follow in such rapid succession that the effect is almost continuous. They are more 
 inclined because such teeth cut more keenly, and the extra power required to work them is readily ap- 
 plied. The harder the wood, the smaller and more upright should he the teeth, and the less the velocity 
 of the saw. The teeth are more set in order to produce a wider kerf, since the large circular plate 
 cannot be made so true, nor keep so true as the narrow straight blade. The setting must be very uni- 
 form, as one tooth projecting beyond the general line will score or scratch the work. ‘'It is generally 
 politic to use for any given work a saw of as small diameter as circumstances will fairly allow, as the 
 resistance, the surface friction, and also the waste from the thickness, rapidly increase»with the diameter 
 of the saw. But on the other hand, if the saw is so small as to be nearly or quite buried in the work, 
 the saw-plate becomes heated, the free escape of the dust is prevented, and the rapidity of the sawing 
 is diminished.” As a general rule the diameter of the saw should be about 4 times the average thick- 
 ness of the wood ; and the flange on the spindle should be as nearly as possible flush with the platform 
 or saw-table. 
 
 In cutting with the grain, the teeth of the saw should he coarse and inclined, and the speed mod- 
 erate, so as to remove shreds rather than sawdust. In cutting across the grain, the teeth should be 
 finer and more upright, and the velocity greater. 
 
 The usual saws used at saw-mills for the manufacture of lumber are rectilinear saws, supported in an 
 upright frame, to which motion is given by a crank, either attached to a small water-wheel, or drum, 
 driven by a steam engine. The feed is generally by a carriage geered and driven by a pawl on the saw 
 frame, working into a ratchet wheel. In water mills the carriage is drawn back by a distinct wheel. 
 In many mills the feed is continuous, the log being drawn in by feed rolls. For the manufacture of 
 boards many saws are set in one frame, the whole log being split at once ; they are called gang saws. 
 Saws without frame, working in a guide at the top, and attached to the crank at the bottom are called 
 muley saws. Circular saws are sometimes used for the manufacture of timber, bat not to any great 
 extent. 
 
 SAWS. Improvement in Tempering and Straightening, Watermans patent. The usual method of 
 tempering saws is to heat and then dip them in oil. — This process is slow, laborious, and costly ; it is 
 a.so disadvantageous, because the saws become warped, and require to be hammered up straight again 
 by hand. 
 
 The present improvement consists in tempering and straightening the saws at one operation. This 
 is done by heating the saws to the proper degree, and then pressing them, with a sudden and powerm. 
 ftroke, between the two surfaces of cold iron. Drop presses are employed for the purpose. The en- 
 graving shows a pair of presses conjoined, one for long the other for circular saws. After being heated 
 the saws are supported in mid air, on buttons attached to the framing at the base of the machine. The 
 heavy drop-weights A A, are now liberated by pulling the cords B B, and the weights fall upon their 
 
SAWS, TEMPERING AND STRAIGHTENING. 
 
 585 
 
 respective saws, drive them down, and press them upon the solid iron base C, with tremendous force 
 The sudden blow hardens the metal by rendering it more dense, and also straightens the saw. 
 
 SCALE, a line drawn upon wood, ivory, etc,, and divided into parts, the lengths of which may be 
 taken off by the compasses and transferred to paper. 
 
 ^ '--I'll \\ . screws aie of two kinds, external or male, and or female, The first kind consists 
 
 of a cylinder, on the surface of which is a projecting fillet, or thread , passing spirally round so as to make 
 equal angles with lines parallel to the axis of the cylinder. The second kind of screw consists o p a cylin- 
 drical perforation through a solid block, bearing a spiral 
 which it is adapted. 
 
 The screw is usually regarded as a continuous circular 
 tance between two contiguous centres of the same thread, 
 
 (o the pitch. . The screw will be a right-hand or a left-hand screw, according as the wedge is wound 
 upon the cylinder, to the right hand or to the left. Double , triple, or quadruple screws are 'those which 
 
 groove, corresponding to the male thread to 
 
 wedge. The pitch of the screw' is the dis- 
 and the screw will be coarse or fine according 
 
686 
 
 SCREWS— SELF-OPERATING SHAVER. 
 
 have a double, triple, or quadruple thread, such, for example, as would be formed by placing 2, or 4 
 strings in contact, and coiling them as a flat band round the cylinder. The screw may also vary in 
 section, that is, the section of the worm or thread may be aru/ular , square , round , etc. 
 
 Micrometer screws are screws of extremely fine pitch, accurately made, and used for graduation. 
 Wood screws is a term applied to the common screw, as used by carpenters. Machine screws are a sim- 
 ilar screw adapted to joiners in iron work. 
 
 SCREWS — SELF-OPERATING SHAVER. This is an improvement in machinery for turning or 
 shaving the heads of the blanks which are to be formed into wood-screws, by J. Cullen Whipple, 
 Providence, Rhode Island. 
 
 In the machines heretofore used for turning or shaving the heads of blanks, the tool or cutter by which 
 they were finished was brought up against them by hand ; but in this improved machine the parts 
 are? made self-acting by means of cams and levers, and other devices connected therewith, arranged for 
 that mrrpose in the manner to be described. 
 
 3241. 
 
 In the accompanying drawings Fig. 3241 is a side, and Fig. 3242 a plan or top view. A A is the 
 frame of the machine, which is made of cast-iron. C C is a tubular or hollow arbor or spindle, which is 
 sustained by and runs in the heads A' A'. The arbor or spindle C is driven by a band on a whirl or 
 pulley D, and it is widened out at its end, C', so as to constitute two cheeks which embrace the jaws 
 E E. Through the tubular arbor C the sliding-bolt F F passes, and serves to close the jaws E, its 
 wedge-formed end F' passing in between the tails a a of the jaws for that purpose. The sliding-bolt F 
 
 bears at. Its outer end against a regulating screw G. This screw passes through the head H' of the lever 
 H, which has its fulcrum at I. When the end H 2 of. this lever is depressed, its end H' will force the bolt 
 F forward, and cause the jaws E to close and embrace the blank which is to be turned The lever H is 
 depressed by means of a cam J, which is carried by a cam-shaft K K. The cam J as it revolves oper- 
 ates upon a lever L, having its fulcrum at L 2 , the short arm of which L' serves to depress the end H 2 ot 
 
SCREW BLANKS. 
 
 5X7 
 
 i hardened roller M, near its end H 2 , upon which L' bears. As represented in Fig. 3241, the lever 
 L is relieved from its action on the lever II by its having fallen into the recess between the points J' J' 
 of the cam J ; the weight II 3 serves to raise the lever H. The arbor C C and the sliding-bolt F F then 
 fall back, release the blank that has been turned, and allow a new one to be fed in. There is a second 
 cam N N, carried by the shaft K, which cam serves to advance the tool or cutter 0 against the head to 
 be turned. This tool or cutter does not differ from those used in other machines for turning the heads 
 of screws. P is a lever upon which the cam N operates to raise the cutter and carry it regularly against 
 the head of the blank ; the fulcrum of this lever is at Q. P' is a branch of the lever P, which by the 
 aid of the set-screw P" allows the action of the cutter to be accurately graduated. The periphery of 
 the cam J is equidistant from its centre K, but that of the cam N has a gradually increasing diameter, 
 to cause the cutter to advance gradually, as it takes a shaving off the head. The cutting part of the. 
 tool is so formed as to cut both the top and bevel of the head at the same time. 
 
 On the same shaft with the cams there is a large spur-wheel R, and motion is given to this wheel by 
 means of a tubular pinion S, on a third shaft T, the bearings of which shaft are on the standards A 2 A 2 . 
 The shaft T also carries the large band-wheel U U, which receives a band from a small band-wheel or 
 whirl Y on the shaft 0. The shaft C and the band-wheel U have their motion continuous, the band 
 around the whirl Y and the wheel U connecting these two parts. W is a sliding clutch-box, having the 
 pinion S attached to it ; and these are moved back and forth by the shipper X, which is governed by 
 the handle Y, a rock-shaft Z on the lower end of which extends to the lower end of the shipper, by 
 means of which the clutch-box is brought into contact with or removed from the clutch-pin, the clutch- 
 ing being effected by a tooth or pin b falling into one of the spaces ccc. For the purpose of arresting 
 the wheel R at the proper time for removing a finished and feeding in a new blank, that is to say, at 
 the period when the cams cease to act upon the levers P and L, there is a pin p projecting from the 
 shipper X at its upper end, on the side opposite to that seen in Fig. 3241, which pin points towards the 
 wheel R, and said wheel has a hole in its side, as at d, Fig. 3241, into which said pin will fall when the 
 wheel comes round to the proper point. The spiral spring e' draws upon the shipper X for the purpose 
 of forcing said pin into the hole, and of arresting the wheel. There is a gage-pin d within the cheeks 
 c, against which a blank e is stopped when fed in ; this pin is regulated by a set-screw/ to suit blanks 
 of different lengths. B is a rest which sustains a blank whilst it is being turned. Within the jaws E E 
 there is a spring g g by which they are opened, and the blanks relieved as the bolt F recedes. The 
 feeding is effected by passing the blank in between the jaws on the side shown in Fig. 3241, where B' 
 is the head of a blank inserted ready for the shaving or turning, by the tool 0. When it has been 
 turned and the jaws opened, it is removed and another inserted by hand ; the blank being stopped by 
 the gage-pin d'. 
 
 One person can readily attend two such machines, his duty being to operate the clutch at the proper 
 time and to feed in a new blank. 
 
 SCREW BLANKS — Merrick’s patent. Fig. 8243 denotes a plan of the blank feeder; Fig. 3244, a 
 longitudinal, vertical, and central section. 
 
 In the said figures A represents a conical hopper, sustained in position by a suitable frame-work B. 
 Two conic frustra C D are disposed within the said hopper, and the one over the other, and sustained 
 upon shafts or bearings, as seen in the drawings. The said conic frustra should revolve in contrary di- 
 rections, as denoted by arrows in the figures. The diameter of the base of the lower frustum is some- 
 what less than the diameter of the lowest part of the interior of the hopper, there being a circular space 
 E left between them of a width to correspond with the diameter of the shank of each of the screw 
 blanks, and permit them to move freely through it, as will be hereinafter described. The exterior sur- 
 faces of the two conic frustra should be roughened or indented in such manner as to act upon the screw 
 or pin blanks and cause them to revolve. Generally speaking, the angles of inclination of the exterior 
 edge of the two conic frustra and the interior edge of the hopper, with respect to a horizontal plane, 
 are to be equal, or about equal, as denoted in Fig. 3244. Between the inner face of the hopper and the 
 outer faces of the two frustra, I extend a partition F, which I secure to the hopper, and permit to 
 approach as near as possible towards the frustra and not interfere with their revolving movements, and 
 at a suitable distance from, or on the right of the said partition, and between the interior face of the 
 hopper and the exterior faces of the frustra, I arrange a revolving beater G. 
 
 The said beater consists of one or more triangular or other suitably shaped plates H H, applied to a 
 horizontal shaft I extending into the hopper, and sustained in bearings at L JVI, as represented in the 
 figures. The said beater may be revolved by an endless band N, which may pass around a grooved 
 pulley o placed upon the shaft P of the upper conic frustum, and thence over guide-pulleys Q R, and 
 under a small pulley S fixed upon the shaft of the beater. The lower conic frustum should have a 
 pulley T fixed upon its axis ; from the said pulley an endless belt V proceeds to and around a pulley 
 Y fixed upon a vertical shaft W. The said shaft has another pulley X fixed upon its upper end, the 
 said pulley communicating with another one (viz. Y upon the shaft of the upper conic frustum) by a 
 cross-band L. Instead of the aforesaid modes of giving motion to the several parts, any suitable geer- 
 work may be adopted. 
 
 The screw or other blanks of the kind are to be thrown previously into the hopper on the left-hand 
 side of the partition F ; as the upper conic frustum C revolves from left to right, and the lower one D 
 from right to left, they will disturb the screw blanks which come in contact with them in such manner 
 as to cause them to successively move downwards the circular space E before mentioned, through which 
 the shanks will fall until arrested in vertical positions by the heads of the blanks coming into contact 
 with the adjacent inclined surfaces of the lower conic frustum and the hopper. 
 
 As the lower frustum continues to revolve, it will advance each screw blank through the circular 
 space E, in the direction in which it (the frustum) travels. The circular space E will thus be filleu 
 with screw blanks, whose shanks stand in vertical positions, as denoted at a a. The object of the beater 
 is to prevent any one of the blanks from overriding the others or disturbing the arrangement of those 
 
SCREWS, BURRING MACHINE FOR. 
 
 588 
 
 which may be in that part cf the space E which exists on the right of the partition F, and between it 
 and the beater. The object of the upper conic frustum is to prevent the blanks from being carried 
 around towards the beater in too great a body ; it also facilitates the downward movements of the 
 Dlanks towards the space E. 
 
 The triangular plates or arms of the beater, shaped as seen in Fig. 324-1, revolve in the same directior 
 a9 does the upper conic frustum. They therefore throw or keep back such blanks as might accumulate 
 to an injurious extent in rear of them. 
 
 3244. 
 
 The next part of the apparatus is that by which the blanks are regularly delivered or fed from the 
 circular space E. It consists of a horizontal slide-plate b, Fig. 3243, (which represents a view of the 
 under sides of the hopper and lower conic frustum D,) affixed to the lower edge of the hopper just on 
 the right of the partition F, the said plate being suitably sustained, so as to slide towards and from the 
 axis of the lower conic frustum. It is forced inwards or towards the same by means of a spring c ap- 
 plied to it and the hopper. The said plate has a circular aperture d cut through one end of it, and a 
 passage e into said aperture cut through the side of the plate, the whole being as seen in the figures. 
 The inner end of the plate is cam-shaped, as seen at f so that when a stud g, projecting from the under 
 side of the lower frustum, is brought into contact with it, the stud shall press the slide outwards, or in 
 a direction away from the frustum, and bring the passage e into line, or so as to correspond with the 
 circular opening E. When this takes place, the movement of the lower frustum will carry one of the 
 screw blanks through the passage e and cause it to drop out of the machine, the circular aperture d 
 being made larger in its diameter than that of the head of the blank. 
 
 There is a small stud h fixed upon the rear side of the 
 entrance e of the slide, as seen in the figure. When the slide 
 is pressed outwards this stud enters between the screw blank 
 wdiich is to be discharged and the one next to it, and thereby 
 prevents the escape of the latter. As soon as the blank is 
 discharged, the slide-plate should be moved inwards by its 
 spring. 
 
 The screw, or pin, or other blank thus discharged, may 
 be received by or into any apparatus calculated to hold or 
 dispose of it for any other operation necessary to be per- 
 formed. 
 
 Instead of the conical frustra and hopper, I sometimes 
 make use of two or more chain-belts arranged parallel to 
 each other and at a proper distance apart, and I apply to 
 them a hopper and beater ; but I consider the said chain- 
 belts, as mechanical equivalents to the aforesaid mechan- 
 ism, by no means so useful or perfect in their operation. 
 
 The beater may be applied to two cylinders or rollers 
 placed parallel to and apart from each other, and provided 
 with a hopper and other contrivances by which the blanks may be dropped between them, and ad- 
 vanced towards the beater. 
 
 In some cases but one conic frustum may be used in connection with the hopper ; in others, a greater 
 number may be necessary, according to circumstances. 
 
 SCREWS, BURRING MACHINE FOR — By J. Cullen Whipple, of Providence, Rhode Island. 
 Fig. 3245 is a front view of the machine, or of that part opposite to which the person stands who is 
 using it; Fig. 3246 is a side view of it; Fig. 3241, a section through the main spindle or arbor; Fig. 
 3248, the under face of the machine; and Fig. 3249, the upper face of the lower end. 
 
 A A is the bed-piece or main-frame, which supports the working parts, and which is usually of cast- 
 iron. A' is a piece projecting therefrom, by which it may be fastened to a bench. B is a whirl or 
 pulley on the main arbor or spindle C C. This arbor runs and slides in collars in the heads A 2 A 2 . The 
 arbor C widens out at its lower end C', and is divided so as to form two cheeks, between which the 
 jaws D D are to be received. These jaws work upon pins a a, which pass through them and through 
 the cheeks. HH is an adjustable slide, which is fastened to the bed-piece A by a- screw b passing 
 through a slot. 
 
 3243. 
 
SCREWS, BURRING MACHINE FOR. 
 
 589 
 
 The part H7 of the adjustable slide, which stands at right angles to the part H, has on its face a 
 piece I fastened to it by a screw c, and this holds the tool G, by which the burs are to be removed fiorn 
 the under side of the heads, the proper form being given to the cutting part G 2 of said tool, to adapt it 
 
 cut away, as shown at e. 
 
 The arbor C 0 is tubular, and there passes through it a sliding-bolt K, having a wedge-formed head K', 
 cy which the jaws DD are to be closed, and this closing will take place as the bolt is drawn back, and 
 
 (tie wedge part K' is forced against the tails ffoi the jaws. F' is a shaft, to which is attached an 
 sum F, that is forked at its outer end F 2 , and is received between collets L L attached to the sliding- 
 
590 
 
 SCREW-CUTTING MACHINE. 
 
 bolt K. EE are a handle and lever, by which the sliding-bolt K and the spindle C are drawn upwards 
 A spiral spring M surrounds the arbor C, and bearing against the uppermost of the heads A 2 and against 
 the pulley B, causes the spindle and bolt to descend, when the handle E is allowed to recede and ren • 
 ders the motion in both directions regular and smooth. As the bolt K descends it is brought into con- 
 tact with the pins g g, which are made fast to the jaws and forces them open. 
 
 In using this machine, when the handle E has been moved back, and the sliding-bolt and arbor have 
 descended, a blank, which has been notched, is fed in through the countersunk opening in the plate J, 
 so as to enter between the jaws. The handle E is then drawn forward, which closes said jaws and 
 brings the head up against the cutting edge of the tool G, by which the removal of the bar is instan- 
 taneously effected, the edge of the tool projecting a little within the countersink. In removing the 
 handle back the blank is liberated and falls out, and another is fed in. 
 
 SCREW-CUTTING MACHINE. This is an invention of 1’eter II. Watson, Esq., of Rockford, 
 Illinois, for cutting serews. 
 
 Fig. 3250 is a perspective view of the machine, as arranged for cutting a male screw upon a rod of 
 metal. 
 
 Fig. 3251 is a view of the face of the bevelled cog-wheel, carrying the dies, cutter and rest, <fcc. 
 
 Fig. 3252 is a vertical transverse section of the carriage and jaws for holding the material to be 
 operated on. 
 
 Fig. 3253 is a plan of the cutter. 
 
 Fig. 3254 is a plan of the tap in the act of cutting the thread in a nut. 
 
 The nature of this improvement consists in combining and arranging in a suitable frame certain 
 known mechanical principles in such a way as to form a new and useful machine, which will enable the 
 mechanic to make screws and nuts with greater dispatch and correctness than by the modes now 
 in use. 
 
 325.*. 
 
 The combination consists of a cog-wheel A and pinion B working into the same, supported by suitable 
 framework C on a permanent bed D, said cog-wheel having attached to its face two sliding-dies E E of 
 the usual form for indenting the screw on the rod of iron F, said dies being turned with said cog-wheel, 
 which is caused to revolve by turning a crank G on the axle of the pinion B, while the rod of iron F is 
 held in a horizontal position between two vertical parallel jaws H, attached to sliding-carriage I, moved 
 in parallel grooves S in the bed towards the dies, by the draft of the dies and chaser, on the rod in 
 cutting the thread which passes through the hub of the wheel, made hollow for that purpose, the screw 
 being perfected and finished before passing through the opening in the centre of the wheel, by means 
 of an adjustable cutter or chaser J, of a shape corresponding to the shape of the thread to be cut, 
 attached tr the face of the wheel between the dies and the wheel directly behind the dies, and in a 
 
SCREW FINISHER. 
 
 591 
 
 [KJsition to bring tlie cutter for chaser in contact with the thread as marked by the dies, so as to cut and 
 perfect it as it leaves the dies, said cutter being attached to the face of the wheel by a set screw J 
 passing through an oblong mortise in its shank. 
 
 A forked rest K is connected to the cog-wheel in the same manner so as to bear against the screw on 
 tire side opposite to that where the cutter is placed being designed to support the screw while under 
 the operation of the chaser or cutter. 
 
 The dies are contained in and supported by a sliding-frame L, and are moved by a right and left 
 screw M, attached by a collar to a stud N inserted into the face of the wheel turned by a milled head 
 or other means, without changing its position longitudinally, the right thread working in a female head 
 in the middle of the top of said sliding-frame L, and the left thread in a female thread in the middle of 
 the sliding follower which slides in the sliding-frame, the lower die being placed against the bottom of 
 the sliding-frame and the upper die against the under side of the follower P, so that when said screw is 
 turned it causes the dies to approach or recede from each other simultaneously by giving the follower 
 and bottom of the frame similar movements in opposite directions. The inner sides of the frame are 
 made of a V-shape to enter corresponding shaped grooves in the ends of the die-plates and follower. 
 The outsides of the sliding-frame are similarly shaped to slide in corresponding grooves made on the 
 under sides of parallel ribs and fastened to the face of the wheel. 
 
 This arrangement is adopted for the purpose of adapting the dies to various diameters of rous upon 
 which screws are to be made, and for centering the dies and rods. 
 
 The jaws for holding the rod of iron on which the screw is to be cut consists of two vertical parallel 
 plates H H, notched or recessed on their inner sides where they grip or clamp the rod F, having their 
 lower ends turned at right angles to enter and slide back and forth in parallel grooves R R on the upper 
 side of the sides of the sliding-carriage I at right angles to the grooves S in the bed in which the 
 carriage I moves. These jaws are opened or closed by means of a right and left horizontal screw T, 
 turned in corresponding right and left female screws in the jaws H H, said screw being prevented from 
 changing its position longitudinally by attaching it to the head of a post U, inserted into the carriage I 
 by a suitable neck V, formed in the middle of the screw between the right and left threads, said neck 
 turning in a corresponding box fixed in the head of the post U. By turning this screw the jaws will be 
 moved simultaneously in opposite directions. 
 
 When a nut is required to be made, the piece of iron W to form the same must be held between the 
 jaws H H instead of the rod, and a tap X with a T-head such as that represented at Fig. 3254 must be 
 placed between the dies ; then, by inserting the tapered end of the tap into the hole in the centre of the 
 piece of iron t,o form the nut, and turning the crank-axle Cf, the thread will be cut by the said tap. 
 
 The frame C containing the cog-wheel and pinion may be made to revolve horizontally on a pivot or 
 centre, and the cog-wheel may be made the driver and the pinion the carrier of the cutting tools and 
 dies, especially in cutting screws of small diameter where speed is required. 
 
 SCREW FINISHER — Whipple’s patent. (We copy from his specification.) The cutter or chaser, 
 by means of which the threads are to be cut, is the same in all respects with that described and claimed 
 by me in the specification of Letters Patent for a machine for cutting the threads upon wood screws, 
 granted to me under date of the 18th of August, in the year 1842; but the combination and arrange- 
 ment of the other parts of the machinery which I am now about to describe, differ essentially from that 
 which was the subject of the patent above referred to. 
 
 Fig. 3255 is a front elevation of such a machine. 
 
 Fig. 3256 is a view of the right-hand end thereof. 
 
 Fig. 3257 is the top view, with the omission of certain parts shown fully in the next figure. 
 
 Fig. 3258 is the top view of the apparatus, into which the blanks that are to be cut are to be fed, and 
 by which they are successively presented to the action of the tool for cutting the thread : most of the 
 operating parts shown in this figure are omitted in each of the others. 
 
 The other figures represent parts in detail which could not be otherwise fully shown. In each of these 
 figures, where the same parts are shown, they are designated by the same letters of reference. 
 
 A A is the frame-work of the machine, which may be of cast-iron. The part A' is a circular horizon- 
 tal table, upon which is sustained a movable zone or ring I F, and the apparatus by which it is governed 
 in its motion, these parts being distinctly shown in Fig. 3258. The zone or ring 1 1' rests loosely upon 
 the horizontal table A', and is kept in place by means of a projecting circular rim N, Fig. 3258, attached 
 to, or in one piece with the circular table A'. The outer portion I of the ring has on its periphery a 
 series of tubes a a into which the blanks are to be fed ; these tubes are countersunk at the upper ends 
 so as to adapt them to the heads of the blanks, and below the countersunk part a portion of each tube 
 is cut away, as shown at a s' a', to admit the end of the cutter or chaser. The blank which is being cut is 
 made to revolve within its tube by means of a revolving screw-driver, which takes into the nick on its 
 head, and is operated in a manner to be presently described. 
 
 J J is the horizontal shaft, which may be connected with the first mover for the purpose of driving 
 the machine; on this shaft there is a bevel-wheel b which geers into the bevel-wheel b', on the 
 vertical shaft C. On this latter shaft there is an endless screw or worm c that mashes into a worm- 
 wheel D D on the main horizontal shaft B B, to which it consequently gives motion ; this shaft runs into 
 boxes a" a" attached to the frame. The shaft C passes up through the table A', in which it has its 
 upper bearing; its continuation is seen at C', and to its upper end is affixed the spur-wheel e', which, 
 geering into the wheel g‘ on a shaft R, which is that which carries the screw-driver, gives motion 
 thereto. 
 
 (I G, shown in detail in Fig. 3264, is a bar which I will call the vertical cutter-slide ; this may be 
 rectangular, and it passes through mortises in the bed A" and in the upper part A'", Fig. 3256, 
 of the frame: in these it slides up and down freely as the thread is chased by the cutter. The cutter 
 i not attached directly to the bar G, but to the upper end of a lever o o which works on a fulcrum- 
 pin in, by which it is connected to said bar ; the lever o allows the cutter to move laterally to and 
 
592 
 
 SCREW FINISHER. 
 
 from the blank to be cut ; the head o' of this lever is widened out for the purpose of sustaining the cut- 
 ter, which is shown in place at xx, Figs. 3257 and 3264. 
 
 This is held in place by the cap P, which has a curved groove on its under side to receive it, the 
 screw q pressing through said cap into the head o' of the lever ; r is a steel spring that bears against 
 the inner side of the lever o, serving to force it back when not pressed up by the apparatus by which 
 tire cutter is made to operate .on the blanks, which I will now describe. 
 
 E, shown most distinctly in Figs. 3255 and 3256, is a cam-wheel made fast on the main horizontal 
 shaft B. The periphery of this wheel is divided into fourteen equal parts, and is cut so as to have on 
 it thirteen tooth-like projections ddd', Fig. 3256, the part d' occupying two of the fourteen divisions, 
 leaving twelve, dd, equal in size. Each of these projections operates as a cam in causing the cutter to 
 operate on a blank ; the number of equal projections determines the number of times that each blank 
 shall be acted on by the cutter, and this number may be varied, but that which I have given is found 
 
 3055. 
 
 sufficient for screws of ordinary size. To the cutter-slide G is attached a hardened steel bearing-piece n, 
 the upper end of which is in the form represented, and is kept in contact with the projections d d of the 
 cam-wheel ; this wheel, therefore, by its revolution, will depress the slide and carry the cutter down : 
 the cam-teeth and the bearing-piece n are made very true and smooth. The faces of the projections d 
 which act on the piece n are finished to an irregular curve, which is such as to cause the direct down- 
 ward motion of the slide to be equal in equal periods of time, the motion of the wheel being uniform. 
 The slide G is raised in the following manner, after each descent: H is a steel spring, shown most 
 plainly in Fig. 3255, which presses on a lifting-piece Y that works on a joint-pin U', and bears against a 
 pin on the back side of the slide G. At the time when this lifting is effected, the cutter is drawn off 
 from the blank by the action of the gage-wheel F and its appendages. 
 
SCREW FINISHER. 
 
 593 
 
 F, Figs. 3255 and 3256, is what I call the gage-wheel, which is affixed to the horizontal shaft B ; this, 
 wheel has a projecting rim i i on its face, like a crown-wheel, which is divided into a number of parts 
 corresponding with those of the projections on the cam-wheel, there being thirteen recesses or notches 
 ij, twelve of which are of one size, whilst the other j' corresponds with the projection d' on the cam- 
 wheel. The gage-wheel F is intended to regulate the feed of the cutter in its successive actions on the 
 blank; under the arrangement described the cutter will, as before remarked, operate twelve times in 
 forming the thread of each screw, the operation on each being completed by one revolution of the shaft 
 B. The cutter is forced up against the blank in the following manner : K' is a lever which ■works on a 
 fulcrum-pin /, and the end K' of which bears upon the face of the projecting rim i i of the gage-wheel 
 during the time that the cutter is operating upon the blank, when the point K is, by the revolution of 
 the wheel F, brought opposite to one of the recesses j, the lever o with its cutter is passed back by the 
 action of the spring r, and at the same instant the piece n falls into one of the notches on the cam-wheel, 
 the slide G rising, consequently, to its original elevation. The lever k advances the cutter against a 
 
 blank by bearing against a sliding-piece t, which bearing is regulated by means of a thumb screw s, 
 Every successive cut of the tool must, of course, be to a greater depth than that which preceded it, and 
 this is effected in the following manner : the face of the projecting rim i i of the wheel F is not in a 
 vertical plane, but each projecting portion rises by a regular inclination beyond that which preceded it, 
 which rise amounts, in machines intended for cutting ordinary |-inch screws, to about one-tenth of an 
 inch in its whole circumference. By this manner of forming the gage-wheel is also obtained the right 
 taper on the screw. T is a conductor down which the cliffs pass from the cutter. 
 
 When the cutting of a screw is to be commenced, the screw-driver must be forced down so as to enter 
 the nick on the blank, and when it has been completed it must be raised therefrom, and the zone or 
 l ing 1 1' must be moved so far round as to bring another blank into the proper situation for the action 
 of the cutter. The apparatus for depressing and raising the screw-driver is as follows : on one side of 
 
594 
 
 SCREW FINISHER. 
 
 the cam-wheel E there is attached a broad rim or hoop vv, Fig. 3255, and the situation of which 
 is indicated also by the dotted lines V Y, Fig. 3256 ; this hoop is continuous for about 10-llths of a 
 circle, about 1-1 1th of it being removed, as at the part h. The outer surface of it is made perfectly 
 .rue and smooth, and there bears on it one end of a crooked lever Q, which is shown separately in Fig. 
 3263 ; its end Q is that which bears on the hoop UU; it has a fulcrum-pin at Q". K" is a pin attached 
 to the upper end of this lever, which pins enter a notch or opening in a piece k', to which is attached 
 tlie vertical sliding-rod P that makes a part of the sliding-frame P P, Fig. 3256, which frame sustains 
 the shaft of the screw-driver : when, by the revolution of the cam-wheel, the end Q' of the lever Q, is 
 brought opposite to the opening h in the hoop U U it falls into it, and the sliding-frame P with the 
 screw-driver attached to it is raised ; the lever Q is kept in contact with the hoop U U by the action of 
 a spring l' that bears against it, and is attached to the circular table A'. The passing of the end of the 
 lever Q into the recess in the hoop U occurs at the moment that a screw has been finished. R, Figs. 3255 
 and 3256, is the shaft of the screw-driver; this shaft passes through and revolves within in the arms 
 0 0 , Fig. 3256, making a part of the stationary screw-driver frame. By means of a feather the shaft R 
 slides freely up and down through the wheel g', which is driven by the wheel c. O, Fig. 3258, is the 
 bottom plate or basis of the frame 0 O, which is fastened on to the top of the circular table A by screws, 
 as at f" /". The upper end of the shaft R is connected to the sliding-frame P by the springs in! n\ Fig. 
 3256. The lowermost of these springs serves to lift it, and the upper one, by means of the thumb- 
 screw o’, serves to adjust it to the different thicknesses of the heads of the blanks, the shaft R is de- 
 pressed, and the screw-driver kept in contact with the blank by the bearing of the lever Q on the 
 hoop U U. 
 
 The removing of the finished screw from the tubes a is effected by the aid of the same hoop TJ that is 
 concerned in the depressing and raising of the screw-driver. S, Figs. 3255 and 3256, is a stationary 
 tubular rod placed vertically, which receives within it a small sliding-rod p'\ there is a slot along the 
 rod S, and a small arm r" attached to the sliding-rod p passes through this slot and bears upon the 
 periphery of the hoop U until it arrives at the opening li ; whilst it bears on the hoop the rod p' is de- 
 pressed, but when it enters the opening h the spiral spring r' forces the rod p f up, which, passing into 
 the tube containing the last but one finished screw, removes it, and it falls into a receiver. 
 
 The apparatus used for causing the zone or ring 1 1' to revolve and carry a blank to the distance ne- 
 cessary to its being operated on by the cutter, is shown in Figs. 3255, 3258, 3259, 3260, 3261, and 3262 
 One side of the worm-wheel D D is widened out, so as to leave a guide-groove fff formed upon it ■ 
 this groove passes uniformly round the wheel, excepting at the point f. Fig. 3255, where it forms an 
 angle, as represented. This groove receives the pin g which constitutes the end of a short arm g", seen 
 separately in Fig. 3262 ; from this arm a shaft M rises vertically and passes through the circular table 
 A', and is firmly attached to an arm or lever K which rests on the top of the table, as seen in Fig. 3258 ; 
 the piece K is shown separately in Fig. 3261, and the part of it to which the shaft M is attached is rep- 
 resented by dotted lines in Fig. 3258. Whilst the pin g remains in the direct part of the groove//, the 
 piece K remains stationary, but where it enters the angular part/' the shaft M is made to revolve par- 
 tially back and forth, and carries with it the piece K. The arm g" is situated below the table A' ; the 
 shaft M to which it is attached has its step in the stud d‘. To cause the pin g to pass readily back into 
 the straight part of the groove/, a spring s', the lower end of which is seen in Fig. 3255, is made to bear 
 against said pin, as shown in Fig. 3262. The finger Y on the piece K draws back the bolt y, Fig. 
 3258, seen separately in Fig. 3259, so as to relieve it from one of a series of notches on the interior edge 
 of the ring 1 1'. These notches x x", &c., correspond in number and position with the tubes for the blanks, 
 and it will be manifest that the bolt y, when inserted in one of these notches, will keep the ring sta- 
 tionary. The bolt y is forced into the notches by means of a spiral spring z, acting against the plate O 
 
SCREWS, MACHINE FOR NICKING. 
 
 595 
 
 To the piece K is also connected the feed-hand L by a joint-pin a'"; this feed-hand carries the ring 1 1' 
 round to the requisite distance. The steel spring b'", which has a bearing on the pin c, serves to throw 
 the feed-arm forward to the proper position to bear against the angle of one of the notches, as seen at x " 
 In describing the various parts of this machine, I have also shown the manner in which they are in- 
 tended to operate, but I will now give a general view of the action of the whole. The tubes a a in 
 the horizontal ring I V are to be kept supplied with blanks, which are to be fed in by hand. Imme- 
 diately preceding the first operation of the cutter on a blank, the lever Q will have occupied the recess 
 li in the hoop U on the cam-wheel, and the lever lv the recess j' in the gage-wheel; and the machine 
 being in motion, the cutter-slide G G will be raised by the action of the spring H on the joint-piece u. 
 
 3264. 
 
 At the commencement of the ascent of the cutter-slide, the cutter will be thrown back by the action 
 of the spring r on the lever o. During this period of time the revolving of the hoop U on the cam-wheel 
 will bring the end of the lever Q, which had occupied the recess h, in contact with said hoop, on the 
 periphery of which it will rise, thereby lowering the screw-driver, when the screw-driver will enter the 
 nick on the blank, which it will cause to revolve rapidly ; the lever K also at the proper instant will 
 leave the recess on the gage-wheel and bear on a projecting part of its rim, bringing the cutter into 
 contact with the blank. That one of the tooth-like projections on the cam-wheel, which is next to the 
 double one, will at the same time be in contact with the steel bearing-piece n, and the cutter will be 
 thereby caused to make its first cut, which being succeeded by the action of the remaining cam-teeth, 
 completes the screw. 
 
 At the time of the completion of the screw last cut, the revolution of the cam-wheel will have brought 
 the hoop U into the position in which the end of the lever Q will enter the recess h, and the screw- 
 driver will be lifted. 
 
 At this time the cutter will have been withdrawn from the screw, and the point g of the arm g", 
 traversing in the guide-groove ff of the worm-wheel, will have attained its greatest variation from its 
 direct course in the angular part of the said groove f, in passing and returning along which it will have 
 given the revolving motion to the shaft M necessary to the operation of the parts concerned in the shift- 
 ing of the ring 1 1' one notch, in the manner above described, which will bring a fresh blank into a situ- 
 ation to be operated on by the cutter, and will also bring the cut screw directly over the rod p'. This 
 screw will be removed by the passing of the small arm r" into the recess h by the revolution of the 
 hoop U, which will leave the rod p' free to rise by the action of the spiral spring r'\ 
 
 SCREWS— MACHINE FOR NICKING. By II. L. Pierson. In this machine the blanks or screws 
 to be nicked are fed or placed in holes made radially in the periphery of a carrying-wheel composed of 
 two plates, the holes being made at the junction of the two pilates, and by the rotation of this wheel 
 they are carried up to and passed under a cutter that forms the nick ; they are griped and held tight 
 during that operation, and then, by the further rotation of the wheel, are liberated and discharged. 
 The nature of this invention consists in griping the blanks in recesses made radially in the face of a 
 wheel by making pressure on one or both sides as the wheel rotates, so that the blanks may be dropped 
 into the holes or recesses with their heads outwards, and griped while passing under the nicking cutter ; 
 aud then, by the further rotation of the wheel, liberated that they may be discharged. 
 
 In Figs. 3265 and 3266 A A is the frame-work of the machine. B is a shaft to which the driving 
 
596 
 
 SCREWS, MACHINE FOR NICKING. 
 
 power is applied, upon which there are two pulleys C C, with bands for driving the different parts of the 
 machinery. D is a whirl on the shaft E, which carries the circular cutter F, by which the screws art 
 to be nicked. A band from the whirl C drives the whirl G on the shaft H, upon which there is an end- 
 less screw or worm I, which takes into a pinion J, upon the upper end of a vertical shaft, the lower end 
 of which runs into a bridge-tree or shifting-bar, the end of which is shown at K, Fig. 3266. This shaft 
 carries an endless screw or worm L, which takes into and drives the toothed wheel M, Fig. 3265, which 
 toothed wheel is on the same shaft with that of N for holding the blanks ; the lower end 0 of the verti- 
 cal shaft being seen in Fig. 3266 ; the connecting-rod P acting upon the bridge-tree or shifting-bar K. 
 
 The blank-wheel N is in two parts, divided through its plane, as shown by the line along its periph- 
 
 ery ; one of these parts is fixed firmly on its axle, whilst the other part slides upon a square eye, or 
 otherwise, upon the axle, and is capable therefore of receding from the fixed part, although it revolves 
 with it. The periphery of this wheel is perforated with holes at the junction of its two parts, as shown 
 in the figures, which holes are of such size as to receive and hold the blanks which are to be nicked. To 
 cause the two portions of this wheel to grip the blank while it is being nicked, there is a friction roller 
 which bears against the outer edge of the periphery of the movable part, immediately under the circu- 
 lar cutter. The dotted lines Q, Fig. 3265, mark its situation, which is opposite to the screw-nut R, 
 Fig. 3266, which confines the friction-wheel box in its place. To react against this friction roller, a simi- 
 lar one is placed opposite to it, and bears upon the fixed portion of the blank-wheel ; the bar S is to 
 sustain this friction-wheel. The shaft which carries the saw is raised or lowered by means of the ad- 
 justing screws TT, and by this means the depth of the nick is perfectly regulated. 
 
 3206. 
 
 Having thus fully described the construction of this machine, its operation will be readily understood. 
 The shaft B being made to revolve by any motive power, the blanks are dropped into the holes in the 
 blank-wheel N as it approaches the cutter, and are held firmly whilst being cut by the pressure of the 
 friction rollers ; and being released from this pressure, they fall out by their own gravity as they are 
 jarried round to the lower part of the machine. 
 
SCREWS, MACHINE FOR SHAVING AND TURNING. 
 
 597 
 
 It will be obvious from the foregoing, that instead of having one part of the wheel firmly attached 
 to the shaft, that both parts may be loose thereon provided they are so connected witli it as to be car- 
 ried around by its rotation, and admit of being pressed together to grip the blanks firmly while passing 
 under the operation of the cutter to be nicked, whether this cutter be a rotating cutter or any other kind 
 of instrument for this purpose, although the rotating cutter is deemed to be the best. Instead of the 
 rollers to press together the two parts of the carrying-wheel, cheeks may be substituted, but with less 
 advantage on account of the friction of the rubbing surfaces ; and instead of making use of two rollers, 
 die one that bears against the face of the permanent part of the wheel may be dispensed with by mak- 
 ing this part of the wheel very strong, and the shaft to run in firm bearings that will afford sufficient 
 strength to resist the pressure required to grip the blanks firmly while being nicked. It will also be 
 obvious tliat the two parts of the wheel may be kept apart for the free reception and delivery of the 
 blanks either by a boss or shoulder on the shaft, or by the introduction of something between them, or 
 by any other equivalent means ; although a projection boss, or shoulder on the shaft, is the simplest and 
 most effective. 
 
 SCREWS, MACHINE FOR SHAVING AND TURNING. Crum & Pierson’s patent. The na- 
 ture of the first part of this invention or improvement in the before-mentioned machine consists in giv- 
 ing to the frame or carriage that carries the carrying and holding wheel (sometimes misnamed the feed- 
 ing-wheel) an intermittent reciprocating motion to withdraw the turned blank and insert the points oi 
 others in the jaws, in succession, instead of giving an endwise motion to the mandrel for this purpose as 
 heretofore ; and also in giving to the carrying-wheel an intermittent rotary motion to present a new 
 blank to the jaws preparatory to the insertion of the same into the jaws by the motion of the carriage. 
 And the second part of this invention consists in shaving the under and upper surface of the heads, 
 within the rim of the carrying and holding wheel, by means of a tool properly adapted to the purpose, 
 which is attached to the end of a vibrating tool-holder, that receives its appropriate motions at right 
 ano-les to the axes of the blank from a cam on the main-shaft. 
 
 z 
 
 In Figs. 3261, 3268, and 3269, a represents a frame properly adapted to the purpose, but which may 
 be changed at the discretion of the constructor. On the table b of this frame, and near one end thereof, 
 there are two ways c c, in which slides a carriage d, that carries the carrying and holding wheel e, for 
 the purpose of withdrawing from the jaws the blank that has been turned, and presenting a new one to 
 the jaws. 
 
 The carrying and holding wheel e is made with a projecting rim f in which spaces are cut out at 
 equal given distances apart, and extending from the fac.e of the wheel to the middle of the width of the 
 projecting rim, and in these recesses are fitted dies g, which are secured by screws to the wheel — the 
 holes that receive the screw-blanks are made half in the end of the dies and the other half in the edge 
 of the recesses, so that by sliding the dies the holes can be adapted to different sizes of screw-blanks. 
 The wheel thus formed is hung on the end of a shaft i, which turns in standards jj of the carriage d, and 
 it is turned the distance required at each operation by a clutch-wheel l, one-half of which is attached 
 permanently to the shaft, and the other to a cog-wheel K, that turns freely on the shaft, the cogs of the 
 wheel Iv engaging with a rack M, that slides freely in the standards of the carriage, so that when this 
 carriage is moved back from the jaws during the operation of the machine, the end of the rack strikes 
 against the end of a set-screw N attached to the frame which slides the rack and turns the carrying- 
 wheel the required distance to take the turned blank from the jaws and present another to be turned ; 
 and on the return motion of the carriage the other end of the rack strikes against another set-screw o, 
 which forces it back, and also the cog-wheel and that half of the clutch-wheel attached to it, the form of 
 the clutch-cogs being such as to permit the two halves to turn in that direction independently of one 
 another, the movable half being forced towards the other by the tension of a helical spring p out the shaft. 
 
 The blanks are fed into the holes of the carrying-wheel e by hand, with the heads inwards, and the 
 required motions are given to the wheel in the following manner : An elbow-lever g, which turns on a 
 
598 
 
 SCREWS, MACHINE FOR SHAVING AND TURNING. 
 
 32C8. 
 
 fulcrum-pin r, has the end of one arm working in a slot s of the carriage d, while the end of the other 
 arm is provided with a roller or wrist which runs in a cam-groove t, made in the face of a plate u, on ;; 
 shaft v , that makes half a revolution for each complete operation ; that is, for every blank that is intro- 
 duced, turned and discharged; and the cam-groove is formed so that from the point 1 to 2, in the direc- 
 tion the reverse of the arrow, it runs out of the circle to move the carriage, and with it the carrying- 
 wheel from the jaws w, to remove a blank that has had the head turned ; and from the point 2 to 3, in 
 the same direction, the groove runs towards the shaft by a curve the reverse of that from 1 to 2, for the 
 purpose of moving the carrying- wheel towards the jaws to present a new blank, the previous motion oi 
 the carriage from the jaws having turned the carrying-wheel a distance equal to a space between two 
 of the holes in the dies to present a new blank, and then from the point 3 to 4 the groove is concentric 
 to hold the carrying-wheel in the same position while the head of a blank is being turned. The other 
 half of the cam-groove is similar to the one described to repeat the operation. So soon as the carrying- 
 wheel has completed its motion towards the jaws and while that part of the cam-groove from the point 
 3 to 4 is passing over the end of the lever q , the carrying-wheel is held firmly in that position to hold 
 the blank firmly while it is being rotated by the jaws and acted on by the cutter ; and this is done by 
 the point of a follower x, that is forced by a helical spring around it to enter one of the series of holes 
 y in the face of the wheel, and preparatory to turning the wheel to shift a blank, a cam z on the periph- 
 ery of the cam-plate u forces up a sliding wedge-piece a', that acts on a follower x, to force it back out 
 of the hole in the wheel, and the moment that the cam passes the follower x is in a condition to be 
 forced by the tension of the spring into the next hole when the wheel is turned round to present another 
 blank to the jaws. 
 
 The screw-blanks thus presented are caught, 
 gripped, and rotated by the pair of jaws w, that are 
 minted to the end of an arbor or mandrel b\ which 
 runs in standards or puppets c c\ and rotated by a 
 belt d' from a pulley e‘ on the driving-shaft/'. This 
 mandrel is hollow, and within it there is a sliding- 
 rod </', one end of which is jointed by links K K with 
 the levers of the jaws, and the other end projects 
 out beyond the back of the mandrel, and is there 
 provided with two collars i i', that embrace the 
 forked end of a lever / that turns on a fulcrum-pin k\ 
 the other end being provided with a roller or wrist 
 that runs in a cam-groove l' in the periphery of a 
 wheel rti on the shaft of the cam that operates the 
 carrying-wheel. The form of this cam-groove is such 
 that from the point 1 to 2 it runs by a sudden curve 
 to the left to open the jaws just as the carrying- 
 wheel begins to move from the jaws to draw out the 
 blank that has been turned ; from 2 to 3 for a short 
 distance it runs ha the direction of the periphery to 
 give time for the carrying-wheel to present a new 
 blank, and then from the point 3 to 4 it runs by a 
 curve the reverse of the one from 1 to 2, to close the 
 jaws and grip the end of a blank, and then the 
 groove runs in the direction of the periphery to com- 
 plete half the circumference from the point 1, the 
 groove for the other half of the circumference being 
 a repetition of the first half to repeat the operation. 
 
 It will be obvious from the foregoing and the fig- 
 ures that the sliding of the rod in the mandrel by its 
 connections will open and close the jaws. So soon 
 as the blank has been presented and gripped the 
 cutter n' is moved up. The cutting edge of this 
 cutter is somewhat in a A form, the edge d being 
 nearly at right angles with the axis of the screw- 
 blank to turn the top of the head, and the other edge 
 
 v' forming the required angle therewith to turn the under surface of the head. This cutter is fitted to 
 a stock q, and slides therein that its cutting edge may be properly set by a screw r. The cutter-stock 
 turns on a fulcrum-pin s' and it rests on the upper end of a sliding-bar t‘, provided with a friction-roller 
 u at the lower end, which is acted upon at the appropriate time ; that is, the moment that the blank 
 is griped by the jaws, by a cam v on the same shaft with the other cams before described ; this cam 
 suddenly runs out from the axis to carry the cutter to the head of the blank and then runs for a short 
 distance by a slight eccentricity to force the cutter gradually against the blank until the head thereof is 
 sufficiently reduced or turned, at which point the cam suddenly runs towards the axis that the cutter 
 may be drawn back from the blank by the weight of the cutter-stock. There are two cutter-cams v 
 to correspond with the double cams for operating the jaws and the carrying-wheel; but it will be ob- 
 vious that by doubling the motion of this cam-shaft relatively to the motions of the other parts of the 
 machine, that the cams may be single. The cam-shaft receives its motions from the mandrel by an 
 endless-screw w on the latter, which actuates a spur-wheel x on one end of a shaft y , the other end o! 
 which has a bevel cog-wheel z , the cogs of which take into the cogs of a similar wheel a? on the cam 
 shaft, shown by dotted lines. As stated before, the screw-blanks are placed in the carrying-wheel, and 
 carried up by its rotation, and when presented to the gripping-jaws the point is forced against a stop L 
 
SCREWS, MACHINE FOR THREADING. 
 
 599 
 
 within the jaws by the motion of the carrying-wheel. And after being turned, the further motion o I 
 the wheel carries them up, their heads resting on to a curved rest c 1 , which is so curved at <P as to per- 
 mit them to fall out by their weight so soon as they reach the top. 
 
 By doubling the length of the carriage, and putting another carrying-wheel on the other end of the 
 shaft, as represented iii Figs. 3267 and 3268, and putting up a duplicate of the mandrel, gripping-jaws, 
 and cutting tools, with their connections, the cam-shaft and cams will answer for two machines, with 
 the exception of the cutter-cams, which must also be doubled to avoid complexity ; but even these mav 
 be dispensed with by changing the form of the cutter-stock and the slide that communicates motion 
 io it from the cutter-cam. 
 
 3269. 
 
 SCREWS, MACHINE FOR THREADING : John Crum’s. Figs. 3270, 3271, 3272, 3273, and 3274. 
 The nature of this invention consists in giving a reciprocating motion to a carriage, in which is hung the 
 shaft of the carrying and holding wheel to draw the stem of the blank from the dies as they rotate to 
 give the pitch to the thread, and to return it to the dies for a succession of operations until the thread is 
 cut, this series of motions being given by a simple segment cog-wheel, the cogs of which act alternately 
 on an upper and a lower rack connected with the carriage. And also in giving to the carrying and 
 holding wheel an intermittent rotary motion (to remove a threaded screw and present a blank) from c 
 wheel below, provided with a pin on its face, which, at every rotation, lifts a lever, the upper end ot 
 which is provided with a hand that acts on the teeth of a ratchet-wheel on the shaft of the carrying- 
 wheel to turn it the required distance for the presentation of a blank, the wheel that carries the lifting- 
 pin being turned a part of a revolution for each cut of the dies by an arm on the shaft of the cam that 
 closes the dies ; the number of teeth or pins on the wheel that are to be struck by the arm on the crank 
 shaft being such for each pin on the other face of the wheel, as to correspond with the number of cuts to 
 be given by the dies for the completion of the thread of the screw. 
 
 The nature of this invention also consists in holding the blanks while under the operation of the dies 
 by the pressure of a spring-roller within the rim. And the last part of this invention consists in closing 
 the dies for the cutting of the threads by means of a cam, which makes one revolution for each cut, and 
 acts by means of a sliding-rod on a lever that forces a rod in the hollow arbor of the jaws to close them 
 when this is combined with a sliding wedge-piece interposed between the sliding-rod and the lever ti 
 increase the depth of the cut at each operation, the said wedge-piece being made to slide for this pur- 
 pose by means of another cam combined therewith. 
 
 In the accompanying figures, a represents a frame, properly adapted to the purpose, and b the main 
 driving-shaft with a pulley c, from which a belt cl passes to a pulley e on a hollow mandrel f that 
 carries the jaws g g, in which are secured dies or chasers It h made in the usual manner. The jaws are 
 joined to ears ii on the end of the mandrel with springs jj interposed, that tend constantly to keep the 
 jaws open, and the rear end of the levers pass into the mandrel and are then acted on to force the dies 
 together in threading the screw by the conical end of the rod Iv, that slides within the mandrel. Tbf 
 
SCREWS, MACHINE FOR THREADING. 
 
 GOO 
 
 rear end of this rod passes out of the mandrel and is acted on -when the jaws are to be closed by the 
 point of an adjustable screw l on the upper end of a lever m, the lower arm of the said lever being 
 acted upon by a sliding-rod n that bears against the face of a cam o on a transverse shaft p. The form 
 of this cam is sucli that from the point 1 to 2, extending one-half of the circumference, it is concentric; 
 at the point 2 it suddenly runs out from the centre to close the jaws, and therefore to make the dies 
 grasp the shank of the blank, and then from this sudden swell to the point 3 it gradually runs out 
 from the centre to increase the bight of the dies, and then by a radial line it runs back to the point of 
 beginning, to permit the springs to force open the jaws that the screw-blank may be run back for a repe- 
 tition of the operation. This cam receives its motions from the mandrel by a train of cog-wheels qr s, the 
 one q being on the shaft of the cam and engaging with the cogs of the one r, which is on the shaft of the 
 
 3270. 
 
 wheel s that is actuated by an endless screw t on the mandrel. Between the lower arm of the lever m 
 and the sliding-rod n there is interposed a wedge-formed slide n' placed at right angles with the 
 sliding-rod n. The end v of this slide is forced by a spring w against the face of a series of cam- 
 formed projections x on the face of a wheel y on a shaft z, the periphery of the said wheel being pro- 
 vided with teeth a', which strike against a pawl or hand b' jointed to the main frame, the shaft of the 
 said wheel y having its bearings in a frame a? attached to and moved by the lever rn, so that at every 
 back motion of the lower end of this lever to open the jaws the wheel y is turned a portion of a revo- 
 lution, that the cam-formed projections x may act on the end of the wedge-formed slide and force it 
 back, and thus cause the threading-cam at each operation to close the cutting-dies more, and in this 
 way complete the cutting of the thread by a series of operations. The cam-formed projections x are as 
 series of planes inclined to the plane of the face of the wheel from which they project, and the length 
 of each is such, relatively to their motion, as that each shall move its whole length for the complete 
 cutting of one screw ; and of course the number of these cam-formed projections will depend on the 
 diameter of the wheel to which they are attached and to the extent of the motion of the said wheel. 
 
 3271. 
 
 The screw-blanks c' are inserted in holes in the rim d' of what is called the carrying and holding 
 wheel e', the rim being made to project from the face of the wheel sufficiently for this purpose. The 
 shaft f of this wheel runs in standards g' of a carriage h' that runs on ways i'i', and this carriage 
 receives a reciprocating motion to move the blank towards and from the chasers or dies by a segment 
 _og-wheel j on the shaft of the threading-cam. The cogs extend over a little less than one-half of the 
 oircumference, and alternately act on the teeth of a lower rack k' to move the carrying-wheel towards 
 the cutting-dies, and then on the cogs of an upper rack l' to run it back to form the thread, the said 
 racks being formed in the opening of a bar attached to the carriage of the carrying-wheel. In this way 
 the motions back anti forth of the carriage are given to determine the pitch of the threads and to return 
 the screw for the repetition of the operation. 
 
 So soon as a screw has been threaded it must be carried away and a blank presented to the dies. 
 This is done in the following manner: On the shaft of the carrying-wheel there is a ratchet-wheel m', 
 which is turned by a hand n' on the end of a lever o' that turns on a fulcrum at p ' ; the lower arm is bent 
 
SCREWS, MACHINE FOR THREADING. 
 
 601 
 
 as at q', so that when lifted the hand on the upper end turns the ratchet-wheel, and with it the carry' 
 ing-wheel, the required distance to carry off the threaded blank and present a new one. The lever is 
 operated in the following manner : On the threading-cam shaft there is an arm r' which, at every rota- 
 tion of the shaft, strikes one of a series of pins s' projecting from a wheel t' to turn it a distance equal 
 to the space between the centres of any two of these pins, and on the other face of this wheel there is a 
 pin u' which, at every entire revolution of the wheel, strikes under the bent arm of the lever o' and 
 gives it the requisite motion to turn the carrying-wheel. Back of the lever o' there is a standard a? 
 with a set-screw 6 2 , against which the lever strikes when thrown back by the weight of the bent part q\ 
 so that by the set of this screw the extent of motion of the lever and the carrying-wheel can be 
 determined. The position of the arm r on the segment cog-wheel shaft relatively to the segment of 
 cogs should be such that the carrying-wheel will be turned for removing the threaded screw and pre- 
 senting a blank when the carriage is farthest from the jaws. And the number of pins s' on the wheel t' 
 must be equal to the number of times it is intended that the chasers or dies shall pass over the blank 
 to complete the thread ; but if desired this number may be doubled, trebled, &c., by having two, three, 
 (fee., pins u on the other face of the wheel. It is, however, preferred to have it as described. In this 
 u r ay it will be seen that the carrying-wheel carries the blanks towards the jaws and inserts the blank 
 in the open dies and moves it back to form the thread, and that these motions are repeated a given 
 number of times until the thread is completely chased or cut, and that when completed the carrying- 
 wheel is turned far enough around to remove the threaded screw and present a hlank to the jaws to 
 undergo the same series of operations. 
 
 3273. 3273. 
 
 While the screw is being cut or chased it is held in its hole in the rim of the carrying-wheel by means 
 of a roller v within the rim of the wheel, and turning on a stud-pin at the end of a lever w, which turns 
 on a fulcrum-pin x\ the roller being held against the inner periphery of the rim of the wheel by a 
 pressure-screw y that bears against the lower end of the lever, so that as the blank is carried up by 
 the wheel to be presented to the dies, the pressure of this roller against the head holds it firmly in the 
 rim of the wheel. The machine can be made double for threading two screws at one and the same 
 time, as shown in the figures, by having two carrying-wheels on the same shaft, and two mandrels with 
 their jaws, dies, and sliding-rods, the two mandrels being geered together by two cog-wheels z' z'. 
 
 It will be obvious from the foregoing that, instead of the segment cog-wheel for giving the recipro- 
 cating motions to the carriage of the carrying-wheel, this may be done by a segment volute-cam, the face 
 of which shall act alternately against the front and back faces of the open space of the bar attached to 
 the carriage, as the object is simply to give a regular reciprocating motion to the carriage, particularly 
 during the operation of threading; for during that operation the motion of the carriage must be regain 
 to give a regular pitch to the thread. As it is only important to give a regular motion to the carriage 
 in the operation of threading, the segment-cog or the volute-cam need only act in this direction, and the 
 motion to run back the carriage for the presentation of the blank may be given by a separate cam of a 
 more sudden curve, or an arm of greater length to perform the return motion faster ; but as these are 
 
G02 
 
 SCREWING MACHINE FOR BOLTS. 
 
 well-known mechanical equivalents, they are simply named to indicate the various modes in which thb 
 part of the invention may be applied. 
 
 SCREWING MACHINE FOR BOLTS. Fig. 3275 is a general plan of the machine. 
 
 F’ig. 3276 is an end view looking upon the frame K, the guide-rods R R and chuck L being removed 
 Fig. 3277 is an end view looking upon the frame N. 
 
 F’ig. 3278 is a general side elevation of the machine corresponding with the plan in Fig. 3275. 
 
 F’ig. 3279 is a face view of the chuck L, seen also in F’igs. 3275 and 3280. 
 
 Fig. 3280 is a corresponding front view of the die-frame, which is retained upon the guide-rods R R 
 of the machine by recesses in the projecting ends. 
 
 The same letters of reference are used in all the figures. 
 
 The head-frame of the machine consists of three pieces fastened to a sole in the usual manner. The 
 forms of the frame-pieces K and N are distinctly shown in the drawings, particularly by Figs. 3276 
 and 3277. A separate view of the intermediate upright is not given, but it is easy to perceive from 
 
SCREWING MACHINE, DOUBLE. 
 
 C03 
 
 Figs. 3275 and 3277, that it has a projecting piece corresponding to that on the bracket N to carry the 
 spindle of the back-speed wheels GH; and that it has besides a centre-bearing corresponding to that 
 of Fig. 3276, for the end of the main-spindle, on which are the pinion C and wheel L>, and which carries 
 the chuck L. 
 
 P, the driving-pulleys on the driving-spindle of the machine. This spindle has a bearing at each 
 end,’ and a bearing also in the middle standard of the frame. The pinion F and wheel I are keyed on 
 the spindle, and geer with the wheel and pinion G and H on a separate spindle, like the back-speed of 
 a lathe. The clutch-wheels A and B are loose on the same spindle which carries the similar pair F 
 and I, so that either of them may be made drivers by means of the clutch S, which slides on the shaft, 
 and is made to turn with it by a sunk feather which connects the clutch and shaft. This clutch is 
 worked by a lever passing to the hand of the operator in the usual manner. The pinion A geers with 
 D on the main-spindle ; B geers with a carrier-pinion E, Fig. 3276, which, in its turn, geers with 0 on 
 the main-spindle. 
 
 3279. 
 
 To explain the action of the machine, suppose the bolt to be centered in the chuck L, and the die- 
 holder, shown by Fig. 3280, to be placed on the guide-rods It R, and brought up so that the end of tne 
 bolt just enters the dies; then the clutch being locked with the pinion A, and the machine set in mo- 
 tion, the chuck will be made to revolve, and with it the bolt to be screwed ; and meanwhile the die- 
 holder being pressed against the end of 1 the bolt, this will enter them as into a nut and will continue 
 to screw itself into them, and by this means the desired thread will be cut upon its circumference. 
 
 The bolt being thus screwed, the next operation is to unscrew it.from the die-holder. For this pur- 
 pose, the clutch is disengaged from the pinion A, and locked with B, which geering with an interme- 
 diate pinion E, reverses the motion, and it at the same time increases the speed in proportion to the 
 increase of diameter of B to A. 
 
 This form of screwing machine has some advantages, but it is wanting in compactness and simplicity 
 of geering, so much the aim of constructors of engineering tools. 
 
 SCREWING MACHINE, DOUBLE — By William Moore, Glasgow. This is one of the most pow- 
 erful and complete machines of its class. It is capable of cutting the threads of screws of 4-£ inches 
 diameter, and, unlike most other machines of the kind, the geering is so adjusted, that both sides of the 
 machine can be employed simultaneously upon bolts and nuts of different sizes. 
 
 A A, the two main standards of the machine, are fixed upon a strong cast-iron sole-plate B, which ex- 
 tends the whole length of the machine, and is securely bolted to a stone foundation. Upon these standards 
 all the geering of the machine is mounted. The driving-spindle J is placed intermediate to the screwing- 
 spindles E and N, and carries the three-speed cone I, by which motion is communicated to the machine. 
 The spindle J has a bearing in each of the two standards, and carries the fast-pinions a and b, also the 
 wheel U and pinion cl, which are cast together, but run loose on the spindle. The pinion a geers into 
 the two spur-wheels S and F, which are loose upon the two screwing-spindles E and N ; and the pinion 
 b geers with the spur-wheel K, which is loose upon a spindle L, immediately under the driving-spindle 
 J. The wheel U geers into the wheel R, and the pinion d into the wheel O, fast on the screwing- 
 spindle N. The spindle L has its bearings also in the two end standards, and carries, besides the 
 wheel K, another wheel M, which geers with the loose wheel G on the screwing-spindle E ; also a fast- 
 pinion c, which geers with the fast-wheel P, upon the screwing-spindle N. The wheels K and M are 
 loose on the shaft L, but are both fast upon a common hollow boss, so that motion being communicated 
 to the wheel K, the other, M, will be carried round in the same direction with an equal velocity. 
 
 The arrangement of the wheels on the large screwing-spindle N is fully shown by Fig. 3286. This 
 spindle is provided with a hollow boss Q, ou which are the fast-wheel R and the loose clutch-wheel S : 
 this last can be brought into action by the sliding-clutch T, upon the same hollow boss Q, and which 
 can be worked from either end of the machine, by the double handle Z Z. The wheels O and P are 
 fast upon the spindle. 
 
 The smaller screwing-spindle carries only the two loose clutch-wheels G and F, either of which can 
 be brought into action by the sliding-clutch H, which is worked by the double handle Y Y. This hau, 
 die is placed upon a small rocking-shaft l, carried on two brackets mm, resting upon the sole-plate of 
 the machine, and has the clutch-fork n keyed upon it, so that in moving the handle from the vertical 
 position, the clutch will be brought into geer with one of the wheels G F, on the spindle E. The handle 
 L Z is in like manner fixed upon a cross-shaft o, carried by the brackets pp, similarly fixed upon the 
 6ole plate; but this shaft, besides the clutcli-fork q for working the clutch T on the hollow boss Q of 
 
604 
 
 SCREWING MACHINE, DOUBLE. 
 
 the screwing-spindle N, has a second fork for working a clutch on the spindle L, to engage and disen 
 gage the loose boss of the wheels K and M. But these two clutches are so fixed in relation to each 
 other, that one of them only can be in action at the same time, consequently, when the wheel S is en- 
 gaged by the clutch T, the wheels K and M must necessarily be loose on the shaft L. 
 
 This arrangement of the geering being kept in view, the action of the machine will easily be com- 
 prehended. Thus supposing motion to be communicated to the speed-cone I, if the clutches T and H 
 be in geer with the wheels S and F respectively, these wheels will be driven by the pinion a, with a 
 speed proportioned to their respective diameters, and in opposite directions. Meantime, the clutch on 
 the under shaft L, being out of action, the wheels K and M will be loose upon it, and the shaft itself 
 will be made to revolve idly by means of the wheel P, which geers with the pinion c upon it. The 
 angular velocity of the wheel F will be immediately communicated to the screwing-spindle E and its 
 chuck V; but the angular velocity of the wheel S will be transferred to the hollow boss Q, and thence 
 
 ”p s 32s3. o 
 
 to the wheel R, which geers with the wdieel U. But this Iasi, being loose upon the driving-shaft, and 
 fast with the pinion d, will communicate its motion to the wheel 0, which is fast upon the screwing- 
 
 x X R X d 
 
 spindle N, and so communicate a reduced speed in the ratio of the numbers — . But let the 
 
 to X B X H 
 
 clutch T be disengaged — the clutch II remaining in geer as before — then the under clutch will engage 
 the wheels K and M to their shaft L, and in consequence this shaft will be driven by the pinion b, which 
 geers with the wheel K, and will drive the wheel P, which is fast on the screwing-spindle N, with a 
 
 b X c 
 
 speed, in the opposite direction to its former motion, determined by the ratio of the numbers — — 
 
 k X 1 
 
 Let the clutch H be brought out of geer with the wheel F, and engaged with the wheel G, then the 
 spindle E will receive an increased speed in the opposite direction to its former motion. Thus the twc 
 screwing-spindles may be driven in either direction independently of each other, and may be employed 
 at the same time to screw-bolts and nuts of different sizes and pitches of thread. 
 
SCREWING MACHINE, DOUBLE. 
 
 605 
 
 The screwing-spindles are of malleable iron to insure strength, and are made hollow to allow the 
 bolts to pass into them as they are screwed. The chucks are fast upon the ends of the spindles, and 
 to these the die-holders are bolted. The die-holder of the smaller spindle is of the common form, and 
 fits into a dovetailed recess Y, from which it can be removed and have its cutters changed at pleasure ; 
 
 3234. 
 
 V 
 
 but that for the larger spindle is differently constructed, as will be observed from the face view of it 
 given in Fig. 3287. This consists of a strong plate W, annularly recessed to receive a ring X, flush 
 with its exterior surface. The ring X has a portion of its circumference cut into teeth to geer with a 
 worm recessed in the plate W, and which can be worked by a handle placed upon the projecting square 
 end of its spindle h. Consequently, as this worm is turned in one direction or the other, the ring X 
 
 3285. 
 
 will be correspondingly affected, and will, by its motion, change the relation of the cutters fff in re- 
 spect of the axis of the chuck. For this purpose, three spiral recesses g g g are formed on the interior 
 circumference of the ring, into which the exterior ends of the cutters project and abut against the 
 inner edges of the spiral recesses. It is therefore clear that if the ring be made to pass through a 
 
 3386. 
 
 3287. 
 
 small aic from right to left, the cutters will be forced to approach the centre ; and conversely, if the 
 motion be from left to right, the cutters will be allowed to expand and receive a larger diameter of 
 bolt. The cutters are accurately fitted into recesses prepared for their reception in the ring e / which is 
 of a piece with the plate W, and the whole is covered by the thin plate j. In this plate are three ra- 
 
606 
 
 SEA-LIGHTS. 
 
 dial slots kkk, through which pass three small round pins projecting from the cutters, for the purpose 
 of guiding them in a rectilinear motion. 
 
 In the operation of screwing, the head of the bolt is caught in the gland-frame D, Fig. 3288, which 
 fits between the guide-rods C C, along which it slides towards the chuck, as the thread is being cut, 
 and the screw thereby formed passes into the hollow interior of the screwing-spindle. When nuts are 
 to be tajiped, they are inserted into glands which fit the guide-rods C 0, at the opposite end of the 
 machine, and the taps are fitted into the square holes in the ends of the spindles. 
 
 SEA-LIGHTS, or Light-Houses. Powerful lights exhibited from lofty towers or headlands, to warn 
 navigators of their proximity to the land. These are divided into coast-lights, which occupy the most 
 salient points ; bay-lights, located within the recessed lines of coast ; channel-lights, arranged to desig- 
 nate some particular course for vessels to steer over a bar or past some danger, and hence are often 
 called “ leading-lights tide-lights, to indicate the height of tide at the port; and lastly, floating-lights, 
 which are vessels from which are exhibited lights to indicate the vicinity of some shoal lying off from 
 the shore, in a position where no permanent structure can be erected. 
 
 Light houses, properly speaking, are of modern origin, and date their efficiency from about the year 
 1780, when Citizen Argand, of Geneva, in Switzerland, invented the admirable lamp that yet bears his 
 name, and which combines in a degree not yet equalled by any other the best principles of combustion, 
 and consequently the evolution of a brilliant light. Previous to the invention of Argand, navigators 
 were compelled to trust to the dim and murky light of wood and coal fires, burned on the tops of tow- 
 ers or lofty promontories, which, when the wind was off shore, must have been nearly or quite concealed 
 by their own smoke. Coal lights have been continued in the Baltic till within ten years past. Smeaton, 
 who erected the celebrated Eddystone Light-house, (justly considered the work of a man of genius, and 
 as displaying a high degree of mechanical skill,) had not the talent sufficient to devise any improvement 
 in the lights, but was obliged to illuminate that superb Pharos with tallow candles ! How great would 
 be his delight, could he now see the beautiful combination of science and practice that are united in the 
 admirable dioptric apparatus of Fresnel, which is installed in the Eddystone Light-house, and makes it 
 one of the most efficient lights in the English Channel ! 
 
 'The great increase of commerce and navigation in the last century, and the repetition of frightful dis- 
 asters by frequent shipwrecks, naturally directed the minds of men to suggest means for ameliorating 
 the danger to which shipping of all classes was then exposed, and an effort to improve the light-houses 
 was one step towards the accomplishment of this desirable object. The clumsy means of producing 
 light from wood and coal fires, prevented the use of a glazed lantern to protect the flame from the 
 furious winds of the Atlantic, and consequently the application of optical instruments to magnify the 
 light. These fires were made in large iron braziers, and about 225 lbs. of coal were used in one night. 
 The first attempt to economize the light from coal or other fires, and to direct the rays to the horizon, 
 was made in 1727, at the Cordouan Light-house, by M. Bitri, an engineer employed to repair that 
 structure. He placed over the flame an inverted cone of tin plates, which reflected all the light inci- 
 dent upon its surface, and must have added materially to its effect as long as the tin was kept polished ; 
 but it is evident that with an open fire beneath the cone, the smoke and gas must speedily have de- 
 stroyed the polish, and with it the reflecting power. 
 
 The effects of a light in giving out rays without any controlling apparatus, will be to fill a sphere 
 whose radius is equal to the distance at which the light is visible. In the light shown from a light- 
 house, those rays which are thrown upwards or downwards beyond the reach of vision, would be totally 
 lost for practical utility, and it therefore becomes necessary to economize the light, to deflect these rays 
 and cause them to assume that direction only in which they are required : in short, our apparatus must 
 be so ordered as to produce a horizontal band or zone of light. To do this we have two methods, both 
 of which have been successfully applied : the first being to collect the rays in a concave mirror, and by 
 its reflective power project them to the horizon ; a circle of these mirrors would thus be visible from 
 every point of the horizon : this is termed the catoptric method. Secondly, to place lenses of a 
 proper form around the light, when all the rays falling upon these will be refracted in a horizontal 
 plane : this is called the dioptric method, and is the more modern and by far most perfect of the two 
 systems. 
 
 As the catoptric or reflector system is the only one used in the United States, we shall briefly de- 
 scribe the form and construction of the reflectors, which ought to be paraboloidal to produce the proper 
 result, though, we regret to say, there are few such reflectors in this country. 
 
 It is proper to premise that a parabola is a curve of the second order, obtained by cutting a cone in 
 a plane parallel to one side, and possessing this remarkable property, that a line drawn from the focus 
 to any point in the curve makes, with a tangent at that point, an angle equal to that which a line par- 
 allel to the axis of the curve makes with that tangent. An inspection of the diagram will render this 
 apparent, and it is easy to see that a revolution of this curve upon its axis will generate a parabolic 
 conoid, which is the form of concave mirror we require for light houses. 
 
 The line P Y G, Fig. 3289, is a parabolic curve, and within it is the focal point F, which is the situa- 
 tion of the lamp-flame in the reflector, of which this may be supposed to represent a section. Now, a 
 ray from the lamp at F falling on the concave surface at d, will be reflected in the direction a f which 
 is parallel to the axis of the curve Y Z, and the angle of reflection bac is equal to the angle of incidence 
 d a e ; in other words, it makes with the normal a z the angle g ah equal to the adjacent angle h a i, and 
 this property belongs to every portion of the surface of the parabola, and consequently the rays from 
 the focal point will be represented by the lines F x x', F w w. 
 
 With respect to the invention of parabolic mirrors, we find them mentioned at a very early period, 
 though not in connection with the subject of illumination, but in reference to their powers of focalizing 
 the rays of the sun to form burning instruments, an inverse principle of that of lamp reflectors. 
 
 In a work entitled “ Pantometria,” by Leonhard Digges, published in London in 1571, the authoi 
 states that, “ with a glasse, framed by a revolution of a section parabolicall, I have se f fire to powdei 
 
SEA-LIGHTS. 
 
 GOT 
 
 half a mile and more distant.” In the prosecution of this subject the celebrated Napier and Sir Isaac 
 Newton experimented with parabolic reflectors before 1673, and lluffon, the great naturalist, with the 
 same object proposed the polyzonal lens, now adapted to light-house purposes, as will be described 
 further on. The first parabolic reflectors for light-houses of which any authentic record remains, were 
 used at the port of Liverpool, England, previous to 1777, for in that year Wm. Hutchinson, dock-master 
 of the port, published his “Practical Seamanship,” and in that work he fully describes the apparatus 
 used in the four light-houses built at Liverpool in 1763. These reflectors were formed to a parabolic 
 curve by a somewhat rude process, which he describes. 
 
 Figs. 3290 and 3291 represent the parabolic reflectors used in the Liverpool light-houses, copied from 
 a plate in Hutchinson’s “Practical Seamanship,” formed of wood, and lined with pieces of looking-glass, 
 or of plates of tin. The oil is kept on a level with the flame by a dripping-pot, supplying the reservoir 
 at the back.* 
 
 3290. 
 
 3291. 
 
 He evidently had a perfect knowledge of the properties of the parabolic reflector, and had also 
 a just idea of its correct application as an illuminating instrument, and he also proposed other 
 aud more complete reflectors, similar to those now in use ; but like Smeaton, who proposed the 
 use of lenses, neither seems to have attempted the production of a more perfect method of obtain- 
 ing the artificial fight, one thinking candles best, the other preferring a rude oil lamp. The inven- 
 tion of Argand’s lamp, in 1780, led the celebrated Chevalier de Borda to propose its union with 
 parabolic reflectors of silver plate, for the illuminating apparatus of light-houses. A suite of Argand 
 lamps and silver-plate parabolic reflectors were accordingly made by Lenoir, the eminent optician, and 
 set up in the Cordouan Light-house in 1783 by M. Teulfere, Ingenieur en chef Ponts et Chaussees, who 
 had just completed the alteration of that structure, and raised it to its present height of 206 feet. 
 This apparatus was arranged, moreover, as a revolving light, being the first one of that kind ever ex- 
 hibited, the reason for which will be explained further on. 
 
 The Trinity House, London, adopted De Borda’s plan of the Argand lamp and silver-plate parabolic 
 reflector in 1788, and the Scottish Light-house Board did the same in 1803, at Inchkeith. The inven- 
 tion was imported into this country in 1810, and, strange to say, a patent was granted for this impor- 
 tation, and our government bought out the patentee in 1812, although the Argand lamp was a French 
 
 * “We have had,” says Mr. Hutchinson, “ and used here in Liverpool, reflectors of 1, 2, and 3 feet focus, and 3, 51, 7 '-, 
 and 12 feet diameter. The smallest made of tin plates soldered together, and the largest of wood covered with plates of 
 looking-glass, and a copper lamp ; the cistern part for the oil and wick stands behind the reflector, so that nothing stands 
 before the reflector to interrupt the blaze of the lamp acting upon it, but the tube that goes through with a spreading 
 burner mouth-piece, to spread the blaze parallel thereto, and with the middle of it just in the focus or burning point of 
 the reflector. The lamps are, like the reflectors, proportioned to make a greater or less blaze as required ; their spread- 
 ng burning parts are from 3 to 12 and 14 inches broad, and are trimmed every four hours. Thus are these light-houses 
 sonstructed, kept, and situated, and have stood the test of a fair trial, and the preference and advantages given to them 
 even by their opponents, as there always will be to new things, commonly calling them new whims, till time and trial 
 confirm them as useful improvements.” 
 
608 
 
 SEA-LIGHTS. 
 
 patent, and, combined with the reflector of De Borda, had then been in public use in the French and 
 English lightdiouses for thirty years. 
 
 The manner in which these instruments are applied to produce the effect of fixed and revolvin'* 
 lights will be understood by inspecting the diagrams. 
 
 Fig. 3292 is a half-plan and elevation of a fixed light of 1G lamps. The reflectors are arranged in 
 two series, one above the other, on circular frames of iron ; at the back of each reflector an Argand 
 lamp is attached, the supply-tube from which passes through a hole cut in the reflector and leading to 
 the burner, which is accurately set in the focus of the instrument. Each reflector must thus illuminate 
 that portion of the horizon towards which it faces, and consequently the distant observer sees the light 
 of but one lamp. 
 
 Fig. 3293 is a half-plan and elevation of a revolving light of four faces. In the diagram there are 
 but two lamps on each of the four sides of a square, though as many as ten lamps are often so placed 
 in lights of the first class. It is obvious in this arrangement that the light from this apparatus must 
 be visible in four directions only, and these 90° apart, or at right angles to each other, while the inter- 
 vening spaces must be dark or eclipsed. By causing this apparatus to rotate slowly on its vertical 
 axis, the bright and dark portions of the square will be presented alternately to the eye of a distant 
 observer ; in other tvords, the light will appear and disappear at intervals of time corresponding to the 
 speed of rotation. Two objects are gained by this arrangement : 1st. A distinctive appearance, by 
 which a light that is eclipsed at regular intervals can never be mistaken for a light steadily visible, or, 
 as they are termed, a fixed light. 2d. The power and brilliancy of the light is greater than in a fixed 
 light, just in proportion to the number of lamps on each face of the frame ; for while in the fixed light 
 we cannot receive the light of but one reflector at a time, owing to the circular form of arrangement, 
 in the revolving light we have the combined power of from two up to ten reflectors at one view, sim- 
 ply by placing so many reflectors on each face of the frame. The difference, then, between the illumi- 
 nating power of the two methods of fixed and rotary lights, is in the ratio of 2 to 1, 3 to 1, or 10 to 1, 
 as the case may be. Consequently, the relative economy of the two plans is in a like ratio. In a 
 fixed light of 24 lamps, the seaman can only have the aid of one reflector, no matter from what direc- 
 tion he views the light ; while in a revolving light of 24 lamps, arranged in groups of eight reflectors on 
 the three sides of a triangular frame, the seaman has eight times as powerful a light presented to his 
 view at short intervals — yet the cost of maintaining these two lights is exactly similar. Notwith- 
 standing the simplicity of this fact, and the cogent reasons that exist for availing ourselves of the 
 superior economy and brilliancy of the revolving light, it is rarely adopted in the United States light 
 houses. With more than 300 lights on our coast, there are yet but 38 revolving fights, against 287 
 fixed. 
 
 In Fig. 32S9 the theoretical properties of the parabola are stated, and it is obvious that if these 
 should remain true in practice, the beam of light from such a reflector would be a simple cylinder ol 
 a diameter equal to the double ordinate of the mirror. Such, however, is fortunately not the case 
 
SEA-LIGHTS. 
 
 609 
 
 3294. 
 
 The size of the flame of the lamp causes a divergence of the reflected light, which divergence increases 
 and decreases with the length of the focal axis of the mirror and the size of the flame. 1 n practice, 
 the effective divergence of the beam of light from a 21-inch reflector of 4 inches focal axis is found 
 to be about 14 degrees in azimuth. Hence we require 26 reflectors in 
 a fixed light, in order to produce a tolerably equal distribution of light 
 around the horizon. If a less number is used, the intervals between 
 each pair of reflectors is poorly lighted, and not visible at any great 
 distance. 
 
 Fig. 3294 is a vertical section of a parabolic reflector, with its lamp 
 in the proper place, and the burner in the focal point. 
 
 Dioptric system of lights . — One of the earliest notices of the applica- 
 tion of lenses to light-houses is in Smeaton’s Narrative of the Eddy- 
 stone Light-house, where it is mentioned that a London optician, in 
 1759, proposed grinding the glass of the lantern to a radius of seven 
 feet six inches. About the middle of the last century, however, lenses 
 were actually tried in several light-houses in the south of England, and 
 in particular at the South Foreland in the year 1752; but their imper- 
 fect figure and the quantity of light absorbed by the glass, which was 
 of impure quality and of considerable thickness, rendered their effect 
 so much inferior to that of the paraboloidal reflectors then in use, that 
 after trying some strange combinations of lenses and reflectors, the 
 former were finally abandoned. 
 
 The celebrated Buffon, in order to prevent the great absorption of light by the thickness of the ma- 
 terial, which would necessarily result from giving to a lens of great dimensions a figure continuously 
 spherical, proposed to grind, out of a solid piece of glass, a lens in steps, or concentric zones. This 
 suggestion of Buffon about the construction of large burning glasses was first executed, with tolerable 
 success, about the year 1780, by the Abbe Rochon. 
 
 The merit -of having first suggested the building of lenses in separate pieces seems to be due to 
 Condorcet, who, in his Eloge de Buffon, published so far back as 1773, enumerates the advantages to 
 ae derived from this method. Sir David Brewster also described this mode of building lenses in 181 1, 
 and in 1822 the late eminent Fresnel, unacquainted with the suggestions of Condorcet or the descrip- 
 tion by Sir David Brewster, explained, with many ingenious and interesting details, the same mode of 
 constructing those instruments which he had discovered for himself in 1819. 
 
 Spherical lenses, like spherical mirrors, collect truly into the focus those rays only which are incident 
 near the axis ; and it is, therefore, of the greatest importance to employ only a small segment of any 
 sphere as a lens. The experience of this fact, among other considerations, led Condorcet, as already 
 noticed, to suggest the building of lenses in separate pieces. Fresnel, however, was the first who actu- 
 ally constructed a lens on that principle, and fully availed himself of the advantages which it affords ; 
 and he has subdivided, with such judgment, the whole surface of the lens into a centre lens and concen- 
 tric annular bands, and has so carefully determined the elements of curvature for each, that it does not 
 seem likely that any improvement will soon be made in their construction. 
 
 Fig. 3295 represents a plan of the great lens ; Fig. 3296 a section through the line A B. 
 
 3295. 
 
 pi' 
 
 The central disk of the lens, which is employed in lights of the first order, and whose focal distance is 
 920 millimetres, or 36'22 inches, is about 11 inches in diameter; and the annular rings which surround 
 '*■ gradually decrease in breadth, as they recede from the axis, from 2J to II inches. The breadth of 
 any zone or ring is, within certain limits, a matter of choice, it being desirable, however, that no part of 
 Vol. n.— 39 1 
 
610 
 
 SEA-LIGHTS. 
 
 the lens should be much thicker than the rest, as well for the purpose of avoiding inconvenient projec- 
 tions on its surface, as to permit the rays to pass through every part of it with nearly equal loss by 
 absorption. The objects to be attained in the polyzonal or compound lens are chiefly, as above noticed, 
 to correct the excessive aberration produced by refraction through a hemisphere or great segment, whose 
 edge would make the parallel rays falling on its curve surface converge to a point much nearer the lens 
 than the principal focus, as determined for rays near the optical axis, and to avoid the increase of ma- 
 terial, which would not only add to the weight of the instrument and the expense of its construction, but 
 would greatly diminish by absorption the amount of transmitted light. 
 
 In applying lenses to the flame of a light house lamp, similar considerations must guide us iu making 
 the necessary arrangements as in the case of reflectors. The size of the flame and its distance from the 
 surface of a mirror have an important practical bearing on the utility of the instrument, and the di- 
 vergence of the resultant beam materially affects its fitness for the purpose of a light-house. So also in 
 the case of the lens ; unless the diameter of the flame of the lamp has to the focal distance of the instru- 
 ment a relation such as may cause an appreciable divergence of the rays refracted through it, it could 
 not be usefully applied to a light-house ; for, without this, the light would be in sight during so short a time 
 that the seaman would have much difficulty in observing it. To determine the amount of this diverg 
 ence of the refracted beam, therefore, is a matter of great practical importance, and we shall briefly 
 point out the conditions which regulate its amount, as they are nearly identical with those which deter- 
 mine the divergence of a paraboloidal mirror illuminated by a lamp in its focus. The divergence, in 
 the case of lenses, may be described as the angle which the fame subtends at the principal focus of the 
 lens, the maximum of which, produced at the vertex of Fresnel’s great lens by the lamp of four concen- 
 tric wicks, is about 5° 9'. 
 
 This will be easily seen by examining Fig. 8297, in which Q q represents the lens, A its centre, F the 
 principal focus, b F and b' F the radius of the flame ; then is the angle b A b' equal to the maximum 
 
 divergence of the lens. Sin b A F = — - = sin 6'AF = ; and twice JAF = the whole 
 
 A r focal distance 
 
 divergence at A. Then for the divergence at the margin of the lens, or at any other point, we have 
 FQ = N /(AQ 2 + AF 2 ) and Q x — y/ (Q F 2 -f- F x 2 ) ; and for any angle at Q, we have sin F Q x 
 _ Far 
 ~FQ' 
 
 On the subject of the illuminating power of the lenses, it seems enough to say that the same general 
 principle regulates the estimate as in reflectors. Owing to the square form of the lens, however, there 
 is a greater difficulty in finding a mean focal distance whereby to correct our estimate of the angle sub- 
 tended by the light, so as to equate the varying distance o*f the several parts of the surface ; but, prac- 
 tically, we shall not greatly err if we consider the quotient of the surface of the lens divided by the sur- 
 face of the flame as the increased power of illumination by the use of the lens. The illuminating effect 
 of the great lens, as measured at moderate distances, has generally beeu taken at 3000 Argand flames, 
 the value of the great flame in its focus being about 16, thus giving its increasing power as nearly equal 
 to 180. The more perfect lenses have produced a considerably greater effect. 
 
 The application of lenses to light-houses is so obvious as to require little explanation. They are ar- 
 ranged round a lamp placed in their centre, and on the level of their focal plane in the manner shown 
 in Fig. 3298, which is a vertical section and plan of a revolving light of eight lenses, that form, by their 
 union, a right octagonal hollow prism, circulating round the flame which is fixed in the centre, and 
 showing to a distant observer successive flashes or blazes of light, whenever one of its faces crosses a 
 line joining his eye and the lamp, in a manner similar to that already noticed in describing the action of 
 the mirrors. The chief difference in the effect consists in the greater intensity and shorter duration of 
 the blaze produced by the lens; which latter quantity is, of course, proportional to the divergence of 
 the resultant beam. Each lens subtends a central horizontal pyramid of light of about 46° of inclina- 
 tion, beyond which limits the lenticular action could not be advantageously pushed, owing to the extreme 
 obliquity of the incidence of light; but Fresnel at once conceived the idea of pressing into the service 
 of the mariner, by means of two very simple expedients, the light which would otherwise have uselessly 
 “soaped above and below the lenses. 
 
 For intercepting 1b r upper portion of the light, he employed eight smaller lenses ol 500 mm. focal 
 
SEA-LIGHTS. 
 
 611 
 
 listance (19'68 inches) inclined inwards towards the lamp, which is also their common focus, and thus 
 forming, by their union, a frustum of a hollow octagonal pyramid of 50° of inclination.. The light fall- 
 ing on those lenses is formed into eight beams rising upwards at an angle of 50° inclination. Above 
 them are ranged eight plane mirrors, as in Fig. 3299, so inclined as to project the beams transmitted by 
 the small lenses into the horizontal direction, and thus finally to increase the effect of the light. In 
 placing those upper lenses, it is generally thought advisable to give their axes a horizontal deviation Oi 
 no or go f rom that of the great lenses, and in the direction contrary to that of the revolution of the 
 frame which carries the lenticular apparatus. By this arrangement the flashes of the smaller lenses 
 precede those of the large ones, and thus tend to correct the chief practical defect of revolving lenticular 
 fights, by prolonging the bright periods. The elements of the subsidiary lenses depend upon the very 
 same principles, and are calculated by the same formulas as those given for the great lenses. In fixing 
 the focal distance and inclination of those subsidiary lenses, Fresnel was guided by a consideration of 
 the necessity for keeping them sufficiently high to prevent interference with the free access to the lamp. 
 He also restricted their dimensions within very moderate limits, so as to avoid too great weight. Their 
 focal distance is the same as that for lenses of the third order of lights. 
 
 Owing to certain arrangements of the apparatus which are necessary for the efficiency of the lamp, 
 but a small portion of those rays which escape from below the lenses can be rendered available for the 
 purposes of a light-house ; and any attempt to subject them to lenticular action, so as to add them to 
 the periodic flashes, would have led to a most inconvenient complication of the apparatus. Fresnel 
 adopted the more natural and simple course of transmitting them to the horizon in the form of flat 
 rings of light, or rather of divergent pencils, directed to various points of the horizon. This he effected 
 by means of small curved mirrors, disposed in tiers, one above another, like the leaves of a Venetian 
 blind an arrangement which he also adopted (see Fig. 3300) for intercepting the light which escapes 
 above as well as below the dioptric belt in fixed lights. Those curved mirrors are, strictly speaking, 
 generated (see Fig. 3301) by portions such as a b of parabolas, having their foci coincident with F, the 
 common flame of the system. In practice, however, they are formed as portions of a curved surface, 
 ground by the radius of a circle, which osculates the given parabolic segment. The mirrors are plates 
 ot glass, silvered on the back and set in flat cases of sheet-brass. They are suspended on a circular frame 
 by means of screws which, being attached to the backs of the brass cases, afford the means of adjusting 
 them, to their true inclination, so that they may reflect objects on the horizon of the light-house to an 
 observer’s eye placed in the common focus of the system. 
 
 Having once contemplated the possibility of illuminating light- houses by dioptric means, Fresnel 
 
012 
 
 SEA-LIGHTS. 
 
 * 
 
 quickly perceived the advantage of employing for fixed lights a lamp placed in the centre of a polyg 
 onul hoop, consisting of a series of refractors, infinitely small in their length and having their uxes ir. 
 plants parallel to the horizon. Such a continuation of vertical sections, by refracting the rays proceed- 
 ing from the focus, only in the vertical direction, must distribute a zone of light equally brilliant in 
 
 33U0. 
 
 every point of the horizon. This effect will be easily understood, by considering the middle vertical 
 section of one of the great annular lenses, already described, abstractly from its relation to the rest of 
 the instrument. It will readily be perceived that this section possesses the property of simply refracting 
 the rays in one plane coincident with the line of the section, and in a direction parallel to the horizon, 
 end cannot collect the rays from either side of the vertical line ; and if this section, by its revolution 
 
 I 
 
 i 
 
 about a vertical axis, becomes the generating line of the enveloping hoop above noticed, such a hoop 
 will of course possess the property of refracting an equally diffused zone of light round the horizon, Fig 
 8302. The difficulty, however, of forming this apparatus appeared so great, that Fresnel determined 
 to substitute for it a vertical polygon, composed of what have been improperly called cylindric lenses 
 but which in reality are mixtiliuoar prisms placed horizontally, and distributing the light which they 
 
SEA-LIGHTS. 
 
 G13 
 
 receive from the focus nearly equally over the horizontal sector which they subtend. This polygon has 
 a sufficient number of sides to enable it to give, at the angle formed by the junction of two of them, a 
 light not very much inferior to what is produced in the centre of one of the sides ; and the upper and 
 lower courses of curved mirrors are always so placed as partly to make up for the deficiency of the 
 light at the angles. The effect sought for in a fixed light is thus obtained in a much more perfect man- 
 ner than by any conceivable combination of the paraboloidal mirrors. 
 
 3305 . 
 
 An ingenious modification of the fixed apparatus is also due to the inventive mind of Fresnel, who 
 conceived the idea of placing one apparatus of this kind in front of another, with the axes of the 
 cylindric pieces crossing each other at right angles. As those cylindric pieces have the property oi 
 refracting all the rays which they receive from the focus, in a direction perpendicular to the mixtilinear 
 cection which generates them, it is obvious that if two refracting media of this sort be arranged as 
 above described, their joint action will unite the rays which come from their common focus into a beam, 
 whose sectional area is equal to the overlapped surface of the two instruments, and that they will thus 
 produce, although in a disadvantageous manner, the effect of a lens. It was by availing himself of this 
 property of crossed prisms, that Fresnel invented the distinction for lights which he calls a fixed light 
 varied by flashes ; in which the flashes are caused by the revolution of cylindric refractors with vertical 
 axes ranged round the outside of the fixed light apparatus already described. See Fig. 3303. 
 
 The loss of light by reflection at the surface of the most perfect mirrors, and the perishable nature of 
 
(314 
 
 SEA-LIGHTS. 
 
 the material composing their polish, led to the introduction of totally reflecting prisms as a substitute 
 for the silvered glass mirrors placed above and below the great refracting belt. These prismatic zones 
 nr catadioptric rings, involve some very difficult calculations in order to determine the proper section oi 
 each. In a dioptric light of the first order there are 13 zones above the refractor and 6 below it. In 
 each one the triangular section differs according to its position with respect to the focal centre of the 
 system of lenses. 
 
 The problem is, therefore, the determination of the elements and position of a triangle ABC, Fig. 
 830-1, which, by its revolution about a vertical axis, passing through the focus of a system of annular 
 lenses or refractors in F, would generate a ring or zone capable of transmitting in a horizontal direction, 
 by means of total reflection, the light incident upon its inner side BC from a lamp placed in the 
 point F. The conditions of the question are based upon the well-known laws of total reflection, and 
 require that all the rays coming from the focus F shall be so refracted at entering the surface B C, as to 
 meet the side B A at such an angle, that instead of passing out they shall be totally reflected from it, 
 and passing onwards to the side C A shall, after a second refraction at that surface, finally emerge from 
 the zone in a horizontal direction. For the solution of this problem, we have given the positions of F 
 the focus, of the apex C of the generating triangle of the zone, the length of the side B C, or C A, and 
 the refractive index of the glass. 
 
 The position of the several prismatic zones is shown in the annexed section, Fig. 3305, or generatrix 
 of the complete system drawn in perspective elevation, Fig. 3306, which is a fixed light of the first 
 order. ABC, catadioptric zones. JD E F, compound dioptric belt with diagonal joints C N M. A' B' C', 
 lower catadioptric zones, one division being left out for free access to lamp. F, focus with flame oi 
 lamp. XXX, diagonal supports for the upper catadioptric zones. HH, service table, on which the 
 lamp rests and where the keeper stands to trim the burner, and which is supported by a pillar resting 
 on the light-room floor. 
 
 The original conception of this magnificent apparatus is seen 
 
 in the annexed diagram, Fig. 3307, which represents a plan r -- — -, 
 
 and vertical section of Fresnel’s fourth order, combining a 
 central annular refractor, with totally reflecting zones above 
 and below. Mr. Stevenson has very unjustly attempted to 
 appropriate this invention as his own ; but the only claim he 
 can properly advance is that of proposing the adoption of this 
 plan of Fresnel's on a larger scale. 
 
 We have next to consider the great lamp, to the proper 
 distribution of whose light the whole of the apparatus above 
 described is applied. Fresnel immediately perceived the ne- 
 cessity of combining with the dioptric instruments which he 
 had invented a burner capable of producing a large volume of 
 flame ; and the rapidity with which he matured his notions on 
 this subject and at once produced an instrument admirably 
 adapted for the end he had in view, affords one of the many 
 
 „ m 
 
 VA 
 
 f /f.v/ 
 
 > J i fjt 
 
 
 ■ \ .■/ ^ 
 
 
 
 .. 
 
 
 
 
 ZZL.JST 
 
 
 proofs of that happy union of practical with theoretical talent, 
 for which he was so distinguished. Fresnel himself has mod- 
 estly attributed much of the merit of the invention of this 
 lamp to M. Arago ; but that gentleman, w 7 ith great candor, 
 gives the whole credit to his deceased friend, in a notice regard- 
 ing light-houses, which appeared in the Annuaire du Bureau 
 des Longitudes of 1831. The lamp has four concentric "burners, 
 which are defended from the action of the excessive heat pro- 
 duced by their united flames, by means of a superabundant 
 supply of oil, which is thrown up from a cistern below by a 
 clockwork movement and constantly overflows the wicks, as in 
 the mechanical lamp of Carcel. A very tall chimney is found 
 to be necessary, in order to supply fresh currents of air to each 
 wick with sufficient rapidity to support the combustion. The 
 carbonization of the wicks, however, is by no means so rapid 
 as might be expected ; and it is even found that after they 
 have suffered a good deal the flame is not sensibly diminished, 
 as the great heat evolved from the mass of flame promotes the 
 rising of the oil in the cotton. The large lamp at the Tour de Corduan burns for seven hours without 
 being snuffed or even having the wicks raised; and, in the Scotch light-houses, it often, with Colza oil, 
 maintains, untouched, a full flame for no less a period than seventeen hours. 
 
 The annexed diagrams will give a perfect idea of the nature of the concentric burner. The first, 
 Fig. 3308, shows a plan of a burner of four concentric wicks. The intervals which separate the wicks 
 from each other and allow the currents of air to pass, diminish a little in width as they recede from the 
 centre. The next. Fig 3309, shows a section of this burner. C C 1 C" C" are the rack-handles for raising 
 or depressing each wick ; A B is the horizontal duct which leads the oil to the four wicks ; L L L are 
 small plates of tin by which the burners are soldered to each other, and which are so placed as. not to 
 hinder the free passage of the air; P is a clamping-screw, which keeps at its proper level the gallery 
 It R, which carries the chimney. The next, Fig. 3310, shows the burner with the glass chimney and 
 damper. E is the glass chimney; F is a sheet-iron cylinder, which serves to give it a greater length, 
 and has a small damper D, capable of being turned by a handle for regulating the currents of air ; and 
 B is the pipe which supplies the oil to the wicks. To prevent the occurrence of such accidents as 1 
 itoppage of the machinery of these lamps, and to render their consequences less serious, various precau 
 
SEA-LIGHTS. 
 
 U1S 
 
 tions have been resorted to. Amongst others, an alarum is attached to the lamp, consisting of a small 
 cup pierced in the bottom, which receives part of the overflowing oil from the wicks, and is capable, 
 when full, of balancing a weight placed at the opposite end of a lever. The moment the machinery 
 stops the cup ceases to receive the supply of oil, and, the remainder running out at the bottom, the 
 equilibrium of the lever is destroyed, so that it falls and disengages a spring which rings a bclJ 
 enfticiently loud to waken the keeper should he chance to be asleep. 
 
 3309. 
 
 There is another precaution of more importance, which consists of having always at hand in the 
 light-room a spare lamp, trimmed and adjusted to the height for the focus, which may be substituted 
 for the other in case of accident. It ought to be noticed, however, that it takes about twenty minutes 
 from the time of applying the light to the wicks to bring the flame to its full strength, which, in order 
 to produce its best effect, should stand at the height of nearly four inches (10 cm \) The inconveniences 
 attending the great lamp have led to several attempts to improve it ; and, among others, M. Delaveleye 
 has proposed to substitute a pump having a metallic piston, in place of the leathern valves, which 
 require constant care, and must be frequently renewed. A lamp was constructed in this manner by M. 
 Lepaute, and tried at Corduan ; but was afterwards discontinued until some of its defects could be 
 remedied. It has lately been much improved by M. Wagner, an ingenious artist, whom M. Fresnel had 
 
 3310. 
 
 
 P3D 
 
 
 Li 
 
 3311. 
 
 employed to carry some of his improvements into effect. In the dioptric lights on the Scotch const, » 
 common lamp, with a large wick, is kept constantly ready for lighting ; and, in the event of the sudden 
 extinction of the mechanical lamp by the failure of the valves, it is only necessary to unscrew and re- 
 move its burner, and put the reserve-lamp in its place. The height of this lamp is-so arranged that its 
 flame is in the focus ot the lenses, when the lamp is placed on the ring which supports the burner of the 
 mechanical lamp; and as its flame, though not very brilliant,. has a considerable volume, it answers the 
 
f>l6 
 
 SEA-LIGHTS. 
 
 purpose of maintaining the light in a tolerably efficient state for a short time, until the light-keepers 
 have time to repair the valves of the mechanical lamp. Only three occasions for the use of this reserve- 
 lamp have yet occurred. 
 
 The most advantageous heights for the flames in dioptric lights are as follows : 
 
 Inches. 
 
 1st Order 10 to 11 centimetres = 3'94 to 4'33 
 
 2d Order 8 to 9 “ =3T5 to 3 54 
 
 3d Order 7 to 8 “ =2 76 to 315 
 
 The dioptric system of Fresnel has another capital advantage over the old system of reflectors, by 
 which a great economy is secured, and what is more important, the amount of light at each station can 
 be graduated to the wants of navigation and the peculiar features of the location. The dioptric system 
 is divided into four orders of magnitude, represented by Figs. 3311, 3312, and 3313, drawn to a uniform 
 scale. Each order may be either a fixed light, a revolving light, or a fixed light varied by flashes, or a 
 flashing light. Here are four different appearances or characteristics, in addition to which, the times ot 
 the flashes and eclipses can be so essentially varied as to produce new distinctive appearances perfectly 
 intelligible to the practical seaman. 
 
 1. Lights of tiie 1st order, Fig. 3212, 3312 . 
 
 have an interior radius or focal distance of 
 92 centimetres, or 36 22 in., and lighted by 
 a lamp of four concentric wicks, consume 
 annually 570 gallons of oil. The revolv- 
 ing lights of this order, having eight large 
 polyzonal lenses, with the catadioptric 
 zones above and below, produce a beam 
 ?>f light whose power is equal to 5000 
 Argand flames of one inch diameter and 
 one and a half inch height. The fixed 
 lights of the same order with catadioptric 
 cupole and zones, produce a beam whose 
 power in all azimuths is equal to 800 
 Argand burners, as above. 
 
 2. Lights of the 2d order. Fig. 3313, 
 having an interior radius of 70 centime- 
 tres, or 27'55 in., lighted by a lamp of 3 
 concentric wicks, consume annually 384 
 gallons of oil. The best revolving lights 
 of this order have a brilliancy equal to 
 3000 Argand burners as above, and the 
 fixed lights of same order, have a power 
 in all azimuths equal to 450 such burners. 
 
 3. Lights of the 3d order, having an 
 interior radius of 50 centimetres, or 19'68 
 inches, and lighted by a lamp with two 
 concentric wficks, consume annually 183 
 gallons of oil. The revolving lights of 
 this order produce a flash equal to 800 
 Argand burners, and the fixed lights of 
 same order have a power in all azimuths 
 of 100 such burners. 
 
 4. Lights of the 4th order, Fig. 3311, 
 nave an interior radius of 15 centimeters, 
 or 5’9 in., and are lighted w r ith a simple 
 Argand burner, consuming annually 48 
 gallons of oil. The flash of this light is 
 equal to 150 burners, and as a fixed light 
 its power in all azimuths is 25 burners. 
 
 There is no combination of reflectors 
 that can be made to produce such powers 
 of light as the first order described above. 
 
 A revolving reflecting light, such as the 
 one on Beachy Head, has three faoes of 
 ten reflectors each, whose combined power 
 of 10X280 = 2800 burners. We have 
 thus three portions of the horizon illumin- 
 ated at the same time with a power equal 
 to 2800 burners. 
 
 The consumption of oil per lamp at 
 Beachy Head is 44 gallons per annum, which, for 30 lamps, gives an aggregate combustion of 1320 gal 
 ions of oil each year. The aggregate power of light produced is 2800 X 3 = 8400 burners. A 1st order 
 dioptric illuminates eight portions of the horizon at one time, with a power of 5000 burners, or ar 
 aggregate effect of 40,000 burners, consuming in one year 570 gallons of oil. 
 
SEA-LIGHTS. 
 
 617 
 
 We hare thus the following comparison : 
 
 1st order dioptric 570 galls, oil 5000X8 points = 40,000 
 
 1st “ catoptric 1320 “ “ 2800X3 “ = 8,000 
 
 Saving in oil = 750 gallons per annum. 
 
 Gain of light = 31,600 burners in eight points. 
 
 Gain of light = 3,200 “ at any one point. 
 
 The greater the amount of sea horizon there is to be illuminated, the more economical and useful 
 becomes the dioptric light ; while the catoptric system increases in first cost, and maintenance after- 
 wards, by the same law. In the. first no increased consumption of oil is caused by extending the area of 
 illumination, while in the latter system the number of lamps and consequent cost and consumption 
 must be increased in proportion to the number of degrees of horizon to be lighted. 
 
 The spheroidal form of the earth requires that the height of a light-house tower should increase pro- 
 portionally to the difference between the earth’s radius and the secant of the angle intercepted between 
 the normal to the spheroid at the light-house and the normal at the point of the light’s occultation from 
 the view of a distant observer. The effect of atmospheric refraction, however, is too considerable to be 
 neglected in estimating the range of a light, or in computing the height of a tower which is required tc 
 give to any light a given range ; and we must, therefore, in accordance with the influence of this element, 
 on the one hand increase the range due to any given height, and, vice versa, reduce the height required 
 for any given range, which a simple consideration of the form of the globe would assign. In ascertain 
 ing this height, we may proceed as follows : 
 
 3314. 
 
 Referring to the accompanying figure, 3314, in which S' d L' is a segment of the ocean’s surface, O the 
 centre of the earth, 17 L a light house, and S the position of the mariner’s eye, we obtain the value of 
 LL' = H', the height of the tower in feet by the formula, 
 o P 
 
 h'= t (1.) 
 
 m which l = the distance in English miles L ' d at which the light would strike the ocean’s surface. We 
 then reduce this value of H' by the correction for mean refraction, which permits the light to be seen at 
 
 2 P 
 
 a greater distance, and which = - — > (2.) 
 
 2 p op 
 
 1 IT 
 
 4 P 
 
 T 
 
 73d 
 
 So as to get, 
 
618 
 
 SEAMING MACHINE. 
 
 an expression which at once gives the height of the tower required, if the eye of the mariner were just 
 on the surface of the water at d, where the tangent between his eye at S and the light at L would 
 touch the sea. We must, therefore, in the first instance, find the distance dS = l', which is the radius ol 
 the visible horizon due to the height S S' — A of his eye above the water, and is, of course, at once ob- 
 tained conversely by the expression, 
 
 Deducting this distance from S L, the whole effective range of the light, we have L d — /, and operating 
 with this value in the former equation, 
 
 we find the height of the tower which answers the conditions of the case. From the above data the 
 following table has been computed : 
 
 11 
 
 Heights in 
 
 A 
 
 Lengths in 
 English 
 
 A' 
 
 Lengths in 
 nautical 
 miles. 
 
 H 
 
 Heights in 
 
 A 
 
 Lengths in 
 English 
 miles. 
 
 A' 
 
 Lengths in 
 nautical 
 miles. 
 
 H 
 
 Heights in 
 
 A 
 
 Lengths in 
 English 
 miles. 
 
 A' 
 
 Lengths in 
 nautical 
 miles. 
 
 5 
 
 2-958 
 
 2-505 
 
 70 
 
 11-067 
 
 9-598 I 
 
 250 
 
 20-916 
 
 18-14 
 
 10 
 
 4-184 
 
 3-628 
 
 75 
 
 11-456 
 
 9 935 
 
 300 
 
 22*912 
 
 19-87 
 
 15 
 
 5123 
 
 4-443 
 
 80. 
 
 11-832 
 
 10-26 
 
 350 
 
 24-748 
 
 2146 
 
 20 
 
 5-916 
 
 5-130 
 
 85 
 
 12T96 
 
 10-57 1 
 
 400 
 
 26 457 
 
 22-94 
 
 25 
 
 6014 
 
 5-736 
 
 90 
 
 12549 
 
 10-88 1 
 
 450 
 
 28-062 
 
 24-33 
 
 30 
 
 7-245 
 
 6-283 
 
 95 
 
 12-893 
 
 11-18 
 
 500 
 
 29-580 
 
 25-65 
 
 35 
 
 7-826 
 
 6787 
 
 100 
 
 13-228 
 
 11-47 
 
 550 
 
 31-024 
 
 26-90 
 
 40 
 
 8306 
 
 7-255 
 
 110 
 
 13874 
 
 1203 
 
 600 
 
 32-403 
 
 28-10 
 
 45 
 
 8-874 
 
 7-696 
 
 120 
 
 14-490 
 
 12-56 
 
 050 
 
 33-726 
 
 29-25 
 
 50 
 
 9-354 
 
 8112 
 
 130 
 
 15-083 
 
 13-08 1 
 
 700 
 
 35-000 
 
 30-28 
 
 55 
 
 9811 
 
 8-509 
 
 140 
 
 15-652 
 
 13-57 
 
 800 
 
 37-416 
 
 32-45 
 
 00 
 
 10-240 
 
 8-886 
 
 150 
 
 17-201 
 
 14-91 
 
 900 
 
 39-836 
 
 34-54 
 
 65 
 
 10-665 
 
 9 249 
 
 200 
 
 18-708 
 
 16-22 
 
 1000 
 
 41-833 
 
 36-28 
 
 If the distance at which a light of given height can be seen by a person on a given level be required, 
 it is only needful to add together the two numbers in the column of lengths A or A', (according as nauti- 
 cal or English miles may be sought,) corresponding to those in the column of heights H, which repre- 
 sent respectively the height of the observer’s eye and the height of the lantern above the sea. When 
 the height required to render a light visible at a given distance is required, we must seek first for the 
 number in A or A' corresponding to the height of the observer’s eye, and deduct this from the whole 
 proposed range of the light, and opposite the remainder in A or A' seek for the corresponding number 
 in II. 
 
 SEAMING MACHINE, DOUBLE. George R. Moore, Philadelphia, Penn. Fig. 331 5 represents 
 a general view of this machine. All the parts that are not lettered compose the frame simply, the con- 
 struction of which is obvious from the drawing, as it is similar to other tin machines, and made of the 
 same materials ; it may, however, be varied. 
 
 We proceed to describe the working machinery, noticing first the two arbors a and b, which are con- 
 nected by cog-wheels, and turned by the crank e. Two heads, d and e, are affixed to the ends of these 
 arbors, and between these heads the double seaming is performed. A pan p is represented in dotted 
 lines, as placed over the head d, on the lower arbor, so as to bring the edge which is to be seamed down 
 between the head c, and a small roller/, hereinafter described. The shape of the head e should be 
 carefully noticed. This head consists of a flanch 1, projecting from a cylindrical surface 2, similar to 
 some other machines now in use ; this cylindrical surface is terminated by a shoulder 3, that connects 
 with a conical moulding 4. The bevel surface of the head e bears first upon the edge of the pan, which 
 is sustained by the head d, the shoulder 3, above named, coming against the bottom, and the edge is 
 forced to yield to the bevel of the head e, as this is screwed down upon it by means of the screw g ; and 
 should any part of the edge be inclined to slip out towards the top of the pan, (as this edge is always 
 composed of three thicknesses,) it is prevented from so doing by the little roller/ attached to the collar 
 k, that surrounds the arbor b near the head. 
 
 At this stage of the operation the crank c is turned, the pan revolves in the machine, and the edge 
 is turned down as far as the bevel part 4, of e , will turn it, while the shoulder 3 prevents the edge oi 
 the pan from bending too far down towards the centre ; after this the head e must be raised up a little 
 by turning the screw g, attached to the box, (in which the arbor b runs,) and then the lever A is brought 
 into use to move the arbor b inwards, by which the cylindrical part 2 of the head e, which is parallel 
 with the outer surface of the head d, is brought over the same and then screwed down towards it, by 
 (he screw g, when, by again turning the crank, the work is completed. The outside shoulder 1 of the 
 head e keeps the bottom of the pan close against the head d. The lever A passes through an aperture 
 in the frame, where it has room to be moved back and forth, and places are fitted to receive it when 
 bo moved, into which it is thrown by a spring, or by its own elasticity. It also passes between two 
 shoulders on the arbor b, and its lower end is connected to the frame by a pivot. Its use has already 
 Wen explained, i is a sliding gage for the purpose of holding in proper position flaring articles, such 
 
619 
 
 SEWERS. 
 
 as the pan represented in the drawing, where the bottom need? to be thrown out from a perpendiculat 
 with the arbors, in order to bring the body parallel with them. This gage consists of a shank that is 
 attached by the scr ewj to the frame, and is terminated by heads branching out for the bottom of the 
 pan to rest against, upon the inside. This is found to be indispensable when the work is much flaring. 
 The heads of this gage are provided with soft or smooth surfaces, to prevent them rubbing the tin so as 
 to mar or injure it. When it is not desirable to use the gage, the work will rest against the head d, 
 which is faced nearly to the edge with leather, although other materials may be used, to prevent its 
 rubbing the tin. 
 
 The piece k is a collar with a lever attached thereto; the collar part of it is fitted upon the arbor b, 
 allowing the arbor to turn freely in it, while the upper end passes through a loop m in the frame, to 
 keep it in an upright position; and below the collar, this lever passes through the little roller/. The 
 only use of the loop m is to bring the roller/ to bear properly upon the work ; and to secure this the 
 oetter, the lever k is made crooked at the top, so that, by pressing it down, this part of it is brought 
 towards the frame, and consequently the roller/ is moved up closer towards e, and vice versa. 
 
 A spring 1 is applied to throw k back as it rises up, to make it easy to get the work properly into 
 die machine. 
 
 SEWERS. Subterranean passages formed for the drainage of a town. The inclination and depth of 
 sewers must be regulated according to circumstances. The Ilolborn and Finsbury regulations require 
 that “the inclination be not less than A inch to every 10 feet in length, and as much more as circum- 
 stances will admit in those portions that are in a straight line, and double that fall in portions that are 
 curved.” It is stated in the regulations of the Westminster Commission, (1836) that the current re- 
 quired for sewers in all cases is 1J inch to every length of 10 feet; hut later regulations order “ that 
 the current of all sewers to be built, be regulated by the commissioners according to surface required to 
 be drained,” without stating any particular inclination. It is, as already observed, frequently a matter 
 of difficulty to obtain sufficient inclination in a sewer, and yet to make it deep enough to drain the 
 basement story of the neighboring houses. 
 
 To remedy the evils of insufficient declivity, the process of flushing has been adopted in the sewers; 
 that is, the water is allowed to accumulate for a time by means of gates or dams, and is then suddenly 
 let loose so as to act like a powerful current in sweeping all the loose matter before it. Sewers receive 
 the drainage of houses by means of small channels or drains , usually of circular form. 
 
 The Westminster commissioners require that the bottoms of private drains shall be 12 inches above 
 the bottom of the sewer ; and they recommend that such drains have a fall of at least \ inch in a foot. 
 Glazed stoneware pipes are excellent substitutes for brickwork in the smaller drains. They are more 
 quickly laid than the others can be built, and they present a much better surface for the rapid flow of 
 the sewage. They are constructed in various forms of bends and junction pieces, and from tire compar- 
 ative thinness of these pipes a much larger capacity is obtained with a given quantity of excavation 
 for laying them, than brickwork sewers, which even for the smallest diameter cannot be less than half 
 a brick, or 4/ inches in thickness. Each pipe has a socket at one end for receiving the plain end of the 
 adjoining pipe. 
 
 The entrances to private drains are usually secured by a stink-trap. These traps are constructed in a 
 variety of forms, but they depend for their action upon the formation of what the chemist calls a water-lute. 
 
 The form of sewer most generally adopted is the egg section, with the smallest end down, so that 
 under a diminished flow the velocity of the current may not be impaired. The size of the sewer must 
 depend on the area to be drained, the requirements of the rain shed, and the house sewage. Knowing 
 the descent, the discharge may be calculated from the usual formulas for the flow of water through pipes, 
 very liberal allowance being made for accidental obstructions, and for excessive falls of rain. Mr. Phil- 
 lips, before the Metropolitan Sanitary Commission of England, classed the sewers by 7 sizes, the first being 
 3.9 x 2.3, with an area of 6.6 square feet, and the 7th class 15 inches x 9 inches, area, 736 souare feet. 
 
620 
 
 SEWING .MACHINES. 
 
 SEWING MACHINES. The application of machinery to the purposes of sewing, is of very recen’ 
 date. It was only since the invention of Mr. Howe in 1846, that it assumed any practical value, and 
 still more recently by other improvements, has it become a household utensil. The germ of the sewing 
 machine is the tambouring machine, a description of which may be found in the Edinburgh Encyclo- 
 pedia, under the head of “ Chainwork.” This machine contained 54 needles, placed one inch asunder 
 and was designed to tambour muslin J wide, one whole row being wrought at the same time. In the de 
 tails of its construction may be found many principles which are still employed. 
 
 8316. The tambour or chain stitch is that in general use 
 
 in the cheaper single thread sewing machines. The 
 form of stitch is represented in fig. 3316; a loop of 
 thread e, is thrust through the fabric c, and held 
 open till the next movement of the needle forces a second loop through the cloth and through the first 
 loop; the first loop is now drawn tightly, and the second loop held open for the third stitch, and so on. 
 At the completion the upper surface of the work shows a single line of thread, the lower a succession of 
 loops : about four and a half yards of thread are a fair average for one yard of this work. The great 
 objection to this stitch is the facility with which it may be ravelled, and on this account it is often used 
 in cloth bleaclieries and printeries, where pieces of cloth are stitched together for the purposes of under- 
 going temporary operations. The low price of these machines has led to a large sale of them, and for 
 many purposes they may be considered of practical value, but the purchase and use of them tend to 
 develop the necessity of sewing machines, and the purchase of the more costly, and by far the most useful 
 double-threaded machines. 
 
 Besides the tambour machine, there are two other single-threaded machines essentially different in 
 principle. 
 
 The first is the invention of Benjamin W. Bean of New York City, patented March 4, 1843, reissued 
 March 10, 1849. The following is the claim : “ What I claim as my invention is the combination of 
 a straight or curved needle and two or more paired wheels for forming the doubles or corrugations of the 
 cloth, the whole being made to operate together essentially as above specified, and in combination there- 
 with. I claim one or more cogged wheels, applied substantially as above specified, and for the purpose 
 of advancing the doubles of the cloth along the needles as above explained.” — This machine formed a 
 running or basting stitch. 
 
 Second, the Robinson & Roper machine ; this is essentially a hand-sewing machine, single-threaded, 
 forming the same kind of stitches that, are made by hand, to wit : back stitches, half and quarter back, 
 side, sail, quilting, hemming, running, etc. Two needles are employed, one above, the other below the 
 cloth, traversing large arcs in a circular slide. The needles are somewhat like those used in the first 
 tambouring machines. The eye opens at the side for the slipping in of the thread, which is retained 
 in its place by a piston sliding down through the upper part of the needle. The principle of the action 
 of the machine is as follows: a needleful of thread, say about 18 inches, is drawn off the spool in its 
 proper position beneath the upper needle, as the upper needle passes down through the cloth it forces 
 down a loop, which is caught in the eye of the lower needle, and by the down movement of this needle, 
 the whole needleful is drawn through the cloth, and by the return motion of the under needle, a loop is 
 presented at the upper surface for a similar operation on the part of the upper needle. When the 
 needleful of thread is exhausted, another is supplied by the operator. The variety of form of stitch is 
 effected by changes in the relative position of the upper and lower needles. 
 
 A similar machine with a rotary feed, has been constructed for the working of eyelet holes; for this 
 improvement a patent was granted to S. H. Roper, November 4, 1856. 
 
 To Elias Howe, Jr., of Spencer, Mass., now of' New York City, is due the credit of inventing the first 
 practical sewing machine. This he patented in 1846, and under licenses from him, are manufactured 
 all the most valuable and practical sewing machines, as I. M. Singer's, Grover & Baker’s, and Wheeler 
 
 The stitch invented by Mr. Howe may be properly 
 termed a lock-stitch ; it is formed with two threads, one 
 above and the other below the fabric sewed ; inter- 
 locked with each other in the centre of the fabric, as 
 in fig. 3317, c being the section of fabric sewed, e the 
 thread above the fabric, and z the thread below the 
 fabric ; a single line of thread extending upon each sur 
 face of the fabric from stitch to stitch. The same 
 thread does not appear both above and below the fabric at each alternate stitch, but that shown upon 
 the upper surface is exclusively the thread e, and that shown upon the lower surface exclusively the 
 thread z. It may be formed by hand with two ordinary needles as follows : 
 
 Take two needles threaded in the ordinary manner, and a piece of soft cloth ; tie the long ends of 
 the thread together, and thrust the needle A, containing the thread e, through the cloth head first, as in 
 fig. 3318, say three-fourths of an inch ; withdraw it slightly, and a small loop of the upper thread e 
 will be formed below the fabric. Through this loop pass the needle with the lower thread s, and with- 
 draw the needle A, entirely from the fabric. The upper thread e, thus surrounds the lower thread z, and 
 interlocks with it; the point of interlocking being drawn into the fabric as in fig. 3318, and the process 
 repeated, a seam will be formed with a single line of thread visible upon each surface, and having the 
 same appearance as that given by stitching. About two and one-half yards of thread are an average 
 for a yard of seam with this stitch, one yard being expended upon the upper surface of the fabric, one 
 upon the lower, and one-half of a yard in passing through the fabric. A firm knot might be tied at each 
 stitch, but as this would involve a waste of thread and form an uneven seam, it has not been practised. 
 
 In the machine invented by Mr. Howe, this stitch was formed in the following manner: one of thr 
 
SEWING MACHINES. 621 
 
 threads was carried through the cloth by means of a needle, the pointed end of which passed through 
 the cloth. The needle had the eye to receive the thread near the point, the other end was held by a bar 
 or arm vibrating upon a pivot. When the needle was forced through the cloth about three-fourths of 
 an inch, a small shuttle carrying a bobbin, filled with silk or thread, was made to pass between the 
 needle and the thread which it carried, and when the needle was drawn up, it forced the thread 
 received from the shuttle into the body of the cloth and formed a stitch ; this being repeated, a seam 
 was formed. 
 
 The cloth to be sewed was suspended perpendicularly upon pins projecting from a baster plate, be- 
 tween which and a pad-plate in front of it, which pressed the fabric upon the baster-plate, it passed, 
 while the stitch was formed, the needle having a horizontal action. This baster-plate with the fabric 
 was moved forward by a mechanical contrivance, by which also the length of stitch was regulated. 
 The invention of the endless rotary feed, and the change of the needle from a horizontal to a vertical 
 action, were the first improvements upon it. The baster-plate was abandoned, the fabric was laid 
 horizontally upon a cloth-plate beneath the vertical acting needle, pressed upon the plate by a cloth 
 presser, and moved forward by a wheel with pins or other projections upon its periphery, penetrating 
 the fabric from beneath, by the action of which also the length of stitch was graduated. The pins 
 penetrating the cloth were objectionable, in not allowing that free movement to the fabric which is 
 essential in forming curved seams. A feed was desired that should not only advance the fabric, but 
 should intermit its action, so that the fabric might be readily turned in any direction. The rough 
 surface feed, with the yielding spring pressure invented by A. B. Wilson, admirably answers these re- 
 quirements, and the patent has become the joint property of the three manufacturers above named. 
 
 Many expedients are devised to increase the speed of shuttle machines — a machine was invented in 
 which the shuttle had a rotary motion, and was made to travel an entire circuit at each stitch ; but 
 the shuttle was kept in its place with difficulty ; the thread was liable to become entangled, and was 
 untwisted at each stitch. Another machine was invented for using a shuttle pointed at both ends, to 
 take a stitch at each movement backwards and forwards. 
 
 The sewing machines of I. M. Singer are identical in their stitch with Howe’s machine. Many im- 
 provements in construction and in the details have been the subjects of patents of either Mr. Singer 
 himself, or have been acquired by purchase. In general arrangement the machines are strong and 
 well made, and the seam secure. They are applied to the sewing of leather as well as that of cloth. 
 
 The Gi'over & Baker Machine. Although making use of two threads to form the stitch, the seam is 
 widely different in its appearance from that of the lock stitch ; it may be called the double-threaded 
 tambour stitch. Fig. 3319 represents the stitch in process of formation, fig. 3320 when completed. 
 
 8319 . , 8320 . 
 
 On the upper surface a single thread is shown, on the lower side three. The upper needle forms a loop 
 as in all machines, and the seam is made by a chain stitch passing through this loop. The stitch is 
 strong and somewhat elastic, and the machine simple, but it is the least economical of thread of all the 
 machines ; the stitch requiring about six and a half yards of thread for each yard of seam. Like all 
 the other sewing machines, the machine embodies several patents. 
 
 The Wheeler & Wilson Machine. In 1851, Mr. A. B. Wilson patented his celebrated lock-stitch 
 machine, which, with the co-operation of Mr. N. Wheeler, was soon introduced into successful opera- 
 tion. The merit of Mr, Wilson’s invention consists in the rough surface feed above mentioned, and in 
 the improved mode and mechanism by which sewing is effected. The main feature of the invention 
 consists in a “ rotating hook,” by which the needle or upper thread upon being passed through the 
 fabric, is enlarged and carried around a stationary bobbin containing the lower tliroad, interlocked with 
 it, and the point of interlocking drawn into the fabric. It may be made by hand in an analogous manner. 
 
 Take an ordinary needle threaded, and a small ball of thread/, say of the size of a hazelnut, as m 
 fig. 3321, tie the ends of the thread together, leaving an inch or two of thread z , unrolled from the 
 ball. Thrust the needle h, head first through the fabric, withdraw it slightly, seize the loop thus made 
 by the upper thread, enlarge it, and instead of passing the ball with the lower thread through this 
 loop, hold the ball stationary and pass the loop around it as in fig. 3321 ; then withdraw the needle 
 entirely from the fabric, and draw up the loop, so that the point of the threads e and z interlocked 
 will be in the centre of the fabric. The manner of making this stitch with the AVheeier & Wilson 
 machine is represented by the following diagrams. 
 
622 
 
 SEWING MACHINES. 
 
 E in fig. 3322 is the rotating hook referred to ; it is formed by cutting away a portion of the peri- 
 phery of the circular concave disk, upon the end of the arbor C. Y, is the concavity of the disk; a, 
 the point of the hook cut clear to the point d ; and d is a small groove diagonal across the periphery of 
 the hook to the point b, where the edge is beveled off ; h is the needle with the eye near the point, that 
 has been thrust through the fabric, with the thread c, the loop of which has just been entered by the 
 point of the hook a. The lower thread is contained in a double convex metallic bobbin, to lie in the 
 concavity Y of the hook E, and held in its position by a concave ring (not represented) between which 
 
 3328. 
 
 and the concave surface of the disk it lies. No axis passes through it, so that a loop of thread can 
 pass around it as around the small ball of thread in the last diagram. By the revolution of the hook 
 after entering the loop of the upper thread, this loop is enlarged and carried forward. Fig. 3323 re- 
 presents the hook as having made about one-third of a revolution, and the lower thread z extending 
 from the lower surface of the fabric to the bobbin in the concavity of the hook containing it. The 
 upper thread e, extends through the fabric from a previous stitch, down into the concavity of the disk, 
 behind the bobbin, around the hook at the point d, thence diagonally along the groove and to the eye 
 of the needle h. Fig. 3324 represents the hook as having made about half a revolution, with the 
 bobbin F in its proper position. The upper thread c has been drawn further behind the bobbin, thence 
 around the hook at d, and diagonally across the periphery of the hook in the groove by b to h the 
 needle. As the hook further revolves to the position in fig. 3325, both lines of the loop e are upon the 
 same side of the hook. The line of thread that extended in fig. 3324 along the groove of the hook 
 from d to b, has slipped off at the termination of this groove, and fallen in front of the bobbin F, so that 
 
 the loop extends behind the bobbin; around the point of the hook a, and across theTront jf the bobbin 
 to the needle h, thus surrounding the bobbin and inclosing the lower thread z. The hook revolving 
 further, the loop e slips off from the point of the hook, and being drawn up, interlocks with the lowei 
 thread z in the fabric, and forms a stitch similar to those represented in the several figures above. 
 
 The following is a description of the accompanying plates. 
 
 To illustrate more clearly the method of making the Howe stitch by the 'Wheeler & Wilton Machine, 
 we have exhibited the rotating hook E and the bobbin F, carrying the lower thread detached from the 
 machine. In the subsequent figures the same parts are represented in their proper places combined with 
 the other parts of the machine, and which are respectively numbered as follows: 1, 1, the Bed Plate 
 supporting 2, 2, the front standards, and 3, 3, the back standards. 4 is the Arbor with its bearings in 
 the front standards, and upon which are, 5 the Rotating Hook, 6 the Feed Cam, 7 the Band Pulley, 8 
 the Eccentric Ring, and 9 the Spooling Spindle, bloving in grooves in the front standards is 10 the Feed 
 Bar ; 11, 11, Ears of the feed bar, 12 the Spiral Feed Spring, working between the left front standard 
 and the left ear of the feed bar. 13 the Feed Tongue, slrtted in the feed bar, and furnished with 14 
 
SEWING MACHINES. 
 
 628 
 
 Feed Points. 15 is the double convex metallic Bobbin, containing the lower thread, and held in the 
 concavity of the rotating hook by 16, the Bobbin Ring, mounted upon 17, the Ring Bar, sliding in a 
 groove in the bed plate, and held by 18 the Thumb Screw. 19 is the Fixed Arm, projecting from the 
 back standard, and supporting 20, the Cloth Pressor, attaclted to the Piston in 2 1, the Piston Cylinder. 
 22 is the Thumb Screw of the cloth presser, 23 the Lever of the cloth presser. 24 is the Needle Rocker, 
 pivoted upon 25, 25, the Centre Screws, 26 the Short Arm of the rocker hinged by 27 to 28 the Con- 
 necting Rod. Upon the rocker is 29 the Needle Arm, bearing 30 the Thread Spool, 31 the Spool Brake, 32 
 the Brake Screw, 33, 33 the Thread Eyelets, 34 tlie Needle Yoke, 35 the Needle. 36 is the Loop Check, 
 37 the Spool Pin, 38 a spool of Thread, 39 a Thread Guide, 40 a Tension Pulley, 41 volute Tension Spring, 
 42 large Seam Gauge, 43 Gauge Screw, 44 Screw for Small Gauge, 45 the fabric sewed, 46 the Cloth 
 Plate, 47 Table Screws. 52 Feed Slots, 53 Set Screw, 54 Feed Stop, 55 Stop Pivot, 56 Thread Guard, 
 57 Thread Hold, 58 small Gauge, 59 Spiral Spring of the cloth presser, 60 Needle Hole. 
 
 In constructing the machine, the lower surface of the bed-plate 1 1 is planed with perfect exactness, 
 and made the plane to which all the planes and lines of the machine are adjusted. The standards 2 2 
 are levelled to a plane parallel with the plane of the bed-plane, at a fixed height above it, and pierced 
 in another parallel plane for the arbor 4, and grooved in a parallel line for the feed-bar 10. The bed- 
 plate is grooved in the same line for the slide bar 1 7 ; the standards 3 3, are pierced parallel to the line 
 of piercing in 2 2, for the centre screws 25 25 ; and the arbor 4, and the rocker 24, are adjusted parallel to 
 each other and to the plane of the bed-plate 1 1. The connecting-rod 28, the short arm 26, the needle 
 arm 29, the fixed arm 19, are adjusted at right angles to the lines of 4 and 24. The rotating hook 5, 
 the bobbin 15 and the needle 35, move in planes vertical to the plane of the bed-plate 1 1. The rotating 
 hook is a portion of the thread of a screw, formed upon the periphery of this circular concave disc. 
 To the left of the notch d, is a portion of another parallel thread of the screw: the disc is cut away 
 below the point d into its concavity, so that the thread of the screw forms the clear point of the hook a. 
 The groove between the two threads of the screw extends diagonally across the periphery of the hook disc 
 to the point 6, where the hook thread of the screw is entirely chamfered off and the groove disappears. 
 The concave surfaces of the disc, and the slide ring 16, contain the bobbin 15 ; the needle 35 is 
 curved to the arc in which the end of the needle arm vibrates. A perfectly rectangular figure is formed : 
 the arbor 4 forms one side ; the connecting-rod 28, the second ; the rocker 24, the third ; and the needle 
 arm 29, with the needle 35, and the rotating hook 5, the fourth. The opening is made for sewing be- 
 tween the needle and the hook. 
 
 The working parts are secured to a frame constituted by the bed-plate 1 1, and the standards there- 
 on, 2 2 and 3 3. The slide ring 16, is adjusted by the set screw 53, to retain the bobbin 15, and allow 
 it to turn freely in the concavity of the hook disc. The needle 35 is adjusted with its head in the needle 
 yoke 34, to vibrate through a small hole 60, in the cloth plate 46, and so that in its rise the eye will 
 be brought just below the point of the hook a, which revolves so close by the right side of the needle 35, 
 that nothing can lie between them as they come opposite each other. The eccentric ring 8, through the 
 connecting-rod 28 and the rocker 24, vibrates the needle arm so that it begins to rise just before the 
 point of the hook a reaches the needle. The pressure of the fabric upon the thread about the needle as 
 it begins to rise, loops the thread slightly upon the right of the needle ; this loop is caught, enlarged 
 and carried around the bobbin as before illustrated. When the loop of thread is about to slip from the 
 hook, as is represented on fig. 3325, it is checked for an instant until the hook has completed its full 
 revolution and enters the next loop, in the process of enlarging which, it draws up the loop already 
 formed. 36, the loop check employed, is a small piece of leather or an equivalent, held in contact with 
 the periphery of the hook, so that the loop cannot pass until the chamfered part b of the hook reaches 
 and frees it, as it does, just as the hook enters the next loop. 
 
 This rotating hook is of singularly ingenious, simple, and novel construction, and is equivalent to 
 several pieces of elaborate machinery. It performs the three operations of enlarging the loop of the 
 upper thread, passing it around the bobbin carrying the lower thread, and tightening the preceding 
 loop 
 
 The bobbin 15 is placed in its proper position, with the thread flowing from the top towards the front 
 of the machine, in which direction it revolves slowly. The thread is wound upon this bobbin with 
 great facility, at the rate of one hundred yards per minute. For this purpose it is placed upon the 
 spooling spindle 9, and the spool of thread upon the spool pin 37 ; the thread is then rewound upon the 
 bobbin by working the treadles as in sewing. 
 
 The upper thread may be used from the original spool 38, or from another spool 30 on which it has 
 been rewound. The tension of the two threads used is a point of importance. To form the stitch per- 
 fectly, the point of interlocking the two threads should be drawn to the centre of the fabric sewed, 
 so that each thread may be held firmly, and the seam present the same appearance upon each side — a 
 single line of thread extending from stitch to stitch. In this machine the tension of the lower thread is 
 rendered sufficiently great by the friction between the surface of the bobbin 15, and the rotating hook 
 in the cavity of which it is placed, the two revolving in opposite directions. The tension of the upper 
 thread must be so adjusted, as to draw the lower thread into the fabric in the formation of a stitch. 
 
 Were the spools of thread always uniform, and the thread uniformly wound, there would be no diffi- 
 culty in using the thread from the original spool. But this is not the case. In fig. 3331 it is shown as 
 fed from the original spool 38, through the thread guide 39, to the tension pulley 40, and thence 
 through the eyelets 33, 33, to the needle 35. The tension is attained by the volute spring 41, pressing 
 upon the wheel 40, which may be regulated at pleasure by the thumb screw at the end. In fig. 3331 
 the tension is attained by the break 31, upon the spool 30, and which is regulated by the thumb screw 
 32. The next point of importance is the Feed This is that part of the mechanism by which the fabric 
 to be sewed is moved forward, and the length of stitch regulated. The length of stitch does not depend 
 at all upon the speed of the machine, but upon the feed alone. 
 
624 
 
 SEWING MACHINES 
 
 22 
 
 22 
 
 ^ rr~ n y ■ ■ ■ 
 
 
 n 
 
 
 
 
 1 
 
 
 
 W 
 
 
 
 Iw 
 
 
 
 § 
 
 
 
 p 
 
 
 
 If 
 
 
 
 H 
 
 eh 
 
 
SEWING MACHINES. 
 
 625 
 
 22 
 
 3333 . 
 
 Vox. II. — 40 
 
SEWING MACHINES. 
 
 B26 
 
 The feed consists of a bar 10, lying in grooves in the front standards, and directly beneath the cleft 
 plate 46. It has a slot nearly its entire length, in which is pivoted, near the left end, a tongue 13, with 
 its right end resting upon the right front standard, armed with two rows of small points 14. The rela- 
 tive position of the feed bar and its appendages to the cloth plate is best seen in fig. 3327. The cloth 
 plate is furnished with a slot 52, through which the feed points when raised project, and enter the fabric 
 held upon the cloth plate by the cloth presser 20. The feed is worked by the cam 6, which rotates with 
 the arbor 4. As this cam revolves, the swell of its periphery strikes the under surface of the feed 
 tongue 15, and raises the feed points 14, through the slot 52, while the swell on the right side of tlia 
 cam 6, presses upon the right ear 11 of the feed bar, and throws it forward. The cam further revolv- 
 ing, brings a point of depression both on its periphery and its side next to the feed bar ear, when the 
 points drop below the surface of the cloth plate, and the feed spring 12, throws the bar back to the left 
 against the feed slot 54, and the next revolution of the cam throws it forward again. It will he ob- 
 served that while the needle penetrates the cloth, the feed points are below the surface of the cloth 
 plate, and intermit their action upon the cloth ; hence the needle constitutes a pivot upon which the 
 fabric may he turned to sew a curved seam of any radius. 
 
 The feed points rising and penetrating the cloth at each stitch, their movement forward determines 
 the length of the stitch, which is graduated by regulating the play of the feed bar. The play of this 
 bar is limited to the difference between the narrowest and the widest parts of the feed cam, which is 
 about one-fourth of an inch, and may be graduated to any length within these limits by the eccentric 
 feed slot 54, against which the heel of the feed bar is thrown by the feed spring 12. As the narrowest 
 or widest parts respectively of this slot are turned towards the feed bar, greater or less play of it is per- 
 mitted, and longer or shorter stitches are made. This slot is turned with great facility while the ma- 
 chine is in motion, by pressing upon the lever with which it is furnished. The machine when used 
 is mounted upon a neat work-table, and driven by sandal treadles and band 7. The fabric to be sewed 
 45, is laid upon the cloth plate 46, beneath the needle, and held by the cloth presser 20. The operator 
 seats herself before the table, on which the machine is placed, with her feet upon the sandal treadles 
 by which the machine is driven. The threads being adjusted, the machine is touched into motion by 
 a gentle pressure of the feet upon the sandals. The cloth moves forward from left to right, and the 
 sewing is accomplished in the manner above described. Two and one-half }ards of thread is the 
 average required for a yard of sewing. There is no limit to the number of stitches that may be made 
 in any given time. The driving wheel is graduated ordinarily so as to make five stitches at each 
 tread, so that from six hundred to one thousand stitches per minute are readily made. 
 
 The bearings and friction surfaces are so slight, that the propelling power required is merely nominal. 
 The rotary hook, feed, bobbin, and other parts at all subject to wear, are made of finely tempered steel • 
 the other parts of the machine are tastefully ornamented, or heavily silver plated. 
 
 Various appliances are furnished for regulating the widths of hems, etc., as 42 and 53. The seam guide 
 42 is attached to the fixed arm 19, by the thumb screw 43, and extends down over the cloth plate with 
 various projections for guiding the work. It is slotted and jointed so as to be adjusted in various positions. 
 A smaller gauge 58 is commonly used, but not in conjunction with 42. It is fastened to the cloth plate 
 by the thumb screw 42. 
 
 Another appendage is the hemmer 48 ; it is used in place of the cloth presser 20, and is in fact a 
 cloth presser, so convoluted, that as the edge of the cloth passes through it is turned down as in ordinary 
 hemming and beautifully stitched. All numbers of thread are used, and needles of various sizes are fur- 
 nished suited to the several threads. 
 
 Thousands are used by seamstresses, dressmakers, tailors, manufacturers of skirts, cloaks, mantillas, 
 clothing, hats, caps, corsets, ladies’ gaiters, umbrellas, parasols, silk and linen goods with complete suc- 
 cess ; sometimes from one hundred to two hundred are used in a single manufactory. The amout of 
 sewing that an operator may accomplish depends much upon the kind of sewing and her experience ; one 
 thousand stitches per minute are readily made, which would form more than a yard of seam with stitches 
 of medium length. Fifty dozens of shirt collars, or six dozens of shirt bosoms are a day’s work. Upon 
 straight seams an operator with one machine will perform the work of twenty by hand ; on an average 
 one probably performs the work of ten seamstresses. 
 
 The Wheeler & Wilson machine is applicable to every variety of sewing for family wear ; from the 
 lightest muslins to the heaviest cloths, it works equally well upon silk, linen, woolen and cotton goods, 
 seaming, quilting, hemming, gathering and felling, performing every species of sewing except making 
 button-holes, stitching on buttons, and the like. Its mechanism is the fruit of the highest inventive 
 genius, combined with practical talent of the first order. Its principles have been elaborated with great 
 care, and it involves all the essentials required in a family sewing machine. It is simple and thorough 
 in construction, elegant in model and finish, facile in management, easy, rapid, and quiet in operation, 
 and reflects additional credit upon American mechanical skill. 
 
 SHEARS ROTARY, Ruggles’ Patent. This machine is made of sizes adapted to cut sheet metal of 
 all numbers. One straight and one circular cutter are employed, the latter being revolved and moved 
 slowly along the edge of the former. The cutting edges do not lap by each other except iu cases of very 
 thin metal, but are at a vertical distance of about half the thickness of the metal to be cut. 
 
 SHEARS ROTARY. Fig. 3320 Js a representation of Bulkley & Norton’s patent improved rotary 
 shears. The shears, when used, stand in the position of the figure, and revolve upon the perpendicular 
 axis or standard. The material to be cut is placed between the clamps, put up to the cutters and the 
 gauge, and held there by the screw, and is cut by one revolution of the machine. 
 
 The cutters revolve and are placed upon a movable half bows, which is easily set to any required 
 size. A boy can use them, and his work will be cut perfect, while there is great saving of labor and 
 stock, as it leaves the work and pieces perfectly smooth. They will cut any wire varying but a hair’s 
 breadth from 21 to 22 inches in diameter. The above shears have been in constant use in various 
 
SHINGLER, BURDEN’S PATENT. 
 
 627 
 
 heavy manufacturing establishments more than five years, and the many high testimonials of theil 
 value which we have seen are fully corroborative of their excellence. When tin is required to be cut 
 in a circular form these shears must be exceedingly useful ; indeed it is said that an entire box of tin 
 can be cut perfectly uniform in twenty :r thirty minutes by this improvement. Orders for these shears 
 are addressed to the patentees and proprietors, Messrs. Bulkley & Norton, Berlin, Conn. 
 
 O 
 
 nr 
 
 3326. 
 
 SHINGLER, BURDEN’S PATENT. This machine, which is represented in Figs. 3327, 3328, and 
 3329, is the invention of Henry Burden, Esq., of the Troy Iron Works, New Tork. Fig. 3327 is a 
 cross-section through B F E. Fig. 332S is a vertical section through B F E. Fig. 8329 is a perspective 
 
 view ABODE are five pillars fixed to the sole-piece 1 1 1 1, which support the strong eccentric eas 
 iog H H H H, and the top journal of the shaft F. G G is a cylinder keyed on the shaft F, and driven 
 
628 
 
 SHINGLER, BURDEN'S PATENT. 
 
SHOT, SMITH’S PATENT. 
 
 629 
 
 in the direction of tlie arrow by the pinion I. K K is a heavy ring or thimble which is allowed to rise 
 and fall up and down the shaft F ; its weight upsets the upper end of the bloom. The dotted line at 
 L represents a large hook, to deliver the bloom when finished. The dotted line at M represents a 
 scraper to clean away any slag that may remain on the flange of the cylinder. D is the rough bloom 
 entering, and E is it just leaving in its finished state. F FFF are flanges to strengthen the, eccentric 
 casing. The bloom being thrown in at the wide end is laid hold of by the cylinder, and by its action 
 pressed against the outside casing, and revolving on its own axis, is taken through the machine, being 
 thus gradually brought to its finished state, and at the same time deprived of its scoria. The under 
 end of the bloom is upset by the action of the flange of the cylinder, and the upper end by that of the 
 lifting-ring K K, in the most perfect manner. 
 
 Tlie advantages are : — 1. The entire saving of shingler’s wages, no attendance being necessary. 2. 
 Very considerable saving in first cost. 3. Great, or rather, almost entire saving of repairs. 4. Con- 
 siderable saving in power. 5. The immense saving, in time, from the quantity of work done, one ma- 
 chine being capable of working to sixty puddling furnaces. 6. Saving of waste, nothing but the slag 
 being thrown otf. 7. The staffs are also saved. 8. It will be readily seen, from the shortness of the 
 time required to finish a bloom, (six or seven seconds,) that tlie scoria can have no time to set, and is 
 thus got rid of much better than when allowed to congeal. 9. The blooms from this machine being 
 discharged so perfectly hot, they roll much better, and thus, besides being much easier on the rollers, 
 the bars produced are much sounder and better finished. 
 
 By the use of this machine, common iron, of an excellent quality, can be finished off at the first heat, 
 viz., that of the puddling furnace. 
 
 SHINGLE MACHINE — JOHNSON'S. Fig. 3331 represents a machine invented by Mr. J. G. 
 Johnson, of Augusta, Maine. 
 
 The machinery is adjusted to a frame of 10 feet in length by 3 feet 10 inches in width. On this is 
 placed a movable carriage E E, which runs on trucks attached to the carriage F F. B is the block or 
 bolt of wood to be sawed, and is held in its place by dogs. C is a piece of wood fastened on the end 
 of the frame, the object of which is to cause the lever D to turn the set-shaft one quarter round every 
 time the carriage returns back ; this lever is raised by a piece of wood fastened to the main frame. To 
 this lever is also fastened a hook, which hooks on to the set-shaft. G G are handles attached to a rod 
 which has a cam on it. By turning the handles up, the rack is raised out of geer and stops the carriage 
 while the operator supplies another bolt or block of wood. The set-shaft has a dog on each end, placed 
 at right angles so as not to set but one of the blocks at a time. Those dogs move two gages that are 
 secured to the headstock which holds tlie block or bolt of wood. The carriage is fed by a decreased 
 motion received from the saw-shaft. 
 
 SHOT. The usual method of making lead shot, is by letting melted lead, with a small alloy of ar- 
 senic, fall through the air from a considerable elevation, and thus the leaden rain becomes cold, and 
 solidified into leaden hail or shot. To carry out this process, high shot towers are erected ; at the top 
 the lead is melted and poured into colanders with different sized holes according to the size of the shot 
 required. That the shot may not be bruised in falling upon one another, they are received into a ves- 
 sel of water at the bottom. To separate the imperfect shot, a slab of polished iron is tilted at a certain 
 angle, and the shot are strewed along the upper part of, the ipclined plane thus formed. The perfect 
 shot proceed rapidly in straight lines and fall into a bin placed to receive them, about a foot distant from 
 the bottom of the slab, whilst the misshapen shot on the contrary, travel with a slower zig-zag motion 
 and fall without any bound into a bin immediately at the foot of the incline. 
 
 To obviate the necessity and expense of high towers,, an expedient is in use for causing the fused 
 metal to fall through an ascending current of air. This method, of which the following is a description, 
 has been secured to David Smith by patent. 
 
 Fig. 3332 is a vertical sectional elevation of a sheet-metal cylinder, set up as a tower within a build- 
 ing, and may be of about twenty inches internal diameter to eaph fifty feet of height, or nearly in such 
 proportions for other heights. Fig. 3333 is a plan at the line A B of Fig. 3332 ; Fig. 3334 is a plan at 
 .he line C D of Fig. 3332 ; Fig. 3335 is a plan at the line E F of Fig. 3332 ; and Fig. 3336 is a plan at 
 
630 
 
 SHOT, SMITH’S PATENT. 
 
the line G H of Fig. 3332. The similar letters used as marks of reference apply to the like parts in all 
 the figures. 
 
 3333. 3334. 
 
 In these, I is a -water-cistern beneath the tower. A is a pipe from any competent blowing apparatus, 
 leading into a hollow annular ring-chamber b, the bottom of which is to be supported in any proper 
 manner above the cistern I ; the inner face forms a portion of the passage for the descending shot ; the 
 upper face c is fitted with holes, as shown in plan Fig. 3334, to pass and dispense the entering and as- 
 cending air ; and the outer side of the ring b forms the base of a truncated cone that sustains a metal 
 cylindrical tower dd , which at ee spreads to pass the ascending blast through a frame //; this is shown 
 in plan Fig. 3335, and in Fig. 3332 is shown as sustaining a cylindrical standard g, the upper central 
 portion of which receives the pouring-pan /t : this is made changeable for each separate size of shot, to 
 be made by larger or smaller holes through the bottoms of the successive pans, as usual ; and round 
 the pouring-pan h is a circular waste-trough i ; round these parts the tower dd finishes also a trumpet- 
 mould K K. The intent and effect of this arrangement is, that the fluid metal running through the 
 pouring-pan h into the ascending current of air, in a tower fifty feet high, when the air is passing up 
 with twice the velocity of the descending metal, will be operated on to the same, or to a greater extent, 
 by the air, as when it falls through the stagnant air in a costly tower of one hundred and fifty feet or 
 more high ; and in the like proportions with the greater or less velocities of the ascending current of air. 
 The particles of metal fall through the open centre of the ring b into the water in the cistern I, where, 
 for convenience, a shoot l carries the particles of metal into a tub m, which may be placed empty, and 
 removed when full through a scuttle n in the cover of the cistern. 
 
 The patentee does not intend to confine himself to the proportions of the parts as here described, nor 
 does he intend confining himself to the parallel cylindrical form of the tower dd, kk, as this may be 
 made more or less conical ; and the other parts may be varied in any way that is substantially tha 
 same, in the means employed to produce the like and intended effects. 
 
 SHUTTLES. See Loom. 
 
 SILEX. The earth of flints. The characteristic ingredient of a great variety of minerals, as 
 quartz, chalcedony, flint, etc. ; the predominating material in granite, many varieties of sand stone 
 and quartz rock. Its chief importance in practical arts is in the manufacture of Glass. 
 
 SILVER. See Metallurgy. 
 
 SINKING. In mining, digging downwards. In rising and sinking a shaft one set of men sink from 
 an upper level while auother set rises from a lower level and meet them. 
 
 SLATE. An argillaceous stone, readily split, and employed to cover the roofs of buildings. Most of 
 the slate at present used in this country is Welsh, but within a few years it has been extensively quar- 
 ried in Vermont. 
 
 Slate has heretofore been all cut out in quarries by hand labor. The workmen with picks cut grooves 
 in the rock to the depth required, and then the slate comes off in thin layers the size of the space be- 
 tween the cut grooves, forming rectangular slabs. To supersede this slow method of quarrying slate. 
 H. J. Bremner, of Nazareth, Pa., has invented a machine, in which cutters are operated so as to feed 
 forward and cut out a groove in one direction, the desired length, and then it (the machine) is turned, 
 and the cutters made to cut a transverse groove, and thus proceed until the rock is so grooved that the 
 space between the side and two end grooves or cut channels, forms a slab of the size desired for the 
 slate ; the slate is then forced out, and splits easily into as many separate slabs as there have been hori- 
 zontal layers from the surface to the depth the cutters have penetrated. 
 
 Machine far Cutting and Trimming Slate. A machine for cutting and trimming slate has been invented 
 and patented by Asa Keyes, of Brattleboro’, Vermont. The nature of the invention consists in apply- 
 ing a rapid succession of stone hammer blows, each of which beats off a minute piece of the slate, 
 while it (the slate) is carried along by a carriage on ways. The wheel which carries the hammers or 
 cutters is heavy, and this weight of the wheel not only furnishes the momentum of the individual blows 
 of each hammer, hut supplies the purpose of a fly-wheel to the machine. The hammers are held into 
 mortises cast in the wheel, by bolts and nuts. 
 
 SLEEPERS. Pieces of timber laid on the ground, taking a bearing their whole length; the term ? 
 applied to the cross ties on a railroad. 
 
 SLIDE-REST. See Tools. 
 
 SLIDE VALVE. See Engines, and Lap and Lead of Slide Valves. 
 
 SLIDING RULE. A rule constructed with logarithmic lines, formed upon a slip of wood, ivory or 
 brass, inserted in a groove in another rule, so that by means of another scale upon the rule itself tha 
 »ontents of a surface or solid may be known. 
 
G32 
 
 SLOTTING MACHINE. 
 
 3337. 
 
 SLOTTING MACHINE, Self-acting, by Caird Co., Greenock. The following figures represent a 
 machine adapted for slotting or paring work of moderate size, and for cutting the key-grooves or seats 
 of wheels not exceeding five feet in diameter. It is at once elegant in design, simple in construction, 
 and capable of adaptation to a great variety of circumstances. 
 
 Fig. 3331 is a front, and Fig. 3339 a side elevation of the machine, showing the general arrangement 
 of the working parts. Fig. 3338 is a general plan, and Fig. 3340 a transverse section of the work-table 
 and part of the framing on which it rests. 
 
 The framing consists of a strong fluted column A, 
 ivith two brackets of proportionate strength for carry- 
 ing the working geer and slotting-bar, and a sole- 
 frame for supporting the work-table and its append- 
 ages, and having a strong bottom plate by which the 
 machine can be bolted to a stone foundation. The 
 whole of this framing consists of a single casting, and 
 therefore may be presumed to possess all the strength 
 and rigidity which can possibly be obtained with the 
 form adopted and the weight of metal employed; 
 two conditions of the utmost importance in machines 
 of this kind, in which the strain varies suddenly from 
 the mere weight of the slotting-bar to the maximum 
 pressure necessary to effect the cut. 
 
 The projecting palms of the brackets are faced and 
 formed with dovetail edges, between which the slot- 
 ting-bar B slides in its up and down motion. Two of 
 these dovetail pieces are attached, by screws, and can 
 be adjusted by set-pins, as they are worn by the 
 sliding action of the bar. On the lower extremity of 
 this bar the slotting-tool is attached by two glands 
 and set-screws, in the usual way ; and, at some dis- 
 tance from jts upper end, it has an adjustable stud 
 fitted into it, to which the upper end of the connecting- 
 rod 0 is jointed. The mode of fixing and adjusting 
 the stud is clearly shown in the front elevation of the 
 machine. From this view it will be observed that the 
 bar has a long slot, occupying about a third of its 
 length at the upper end, between the parallel cheeks 
 of which the rectangular body-part of the stud is 
 accurately fitted. This part of the stud is formed 
 with shoulders which bear against the inside of the 
 bar, and has a strong screwed pin projecting from it3 
 exterior surface, on wliich a large pinching-nut is 
 passed. This nut being screwed tight against the face 
 of the bar, the stud is effectually secured from shifting 
 its position in the slot, by the friction induced between 
 the bar and the shoulders of the stud on the inside, 
 and the nut on the outside. 
 
 The rectangular body of the stud is traversed by a 
 long square-threaded screw, which occupies the whole 
 length of the slot in the bar, and which can be worked 
 by the small hand-wheel P, fixed on its upper end. 
 
 This screw is so fitted into the machine as to have no 
 end-long motion independent of the bar; but when 
 turned by means of the wheel P, on its upper extrem- 
 ity, it will cause the stud to assume any required posi- 
 tion in the slot. But it is easy to perceive that by 
 changing the position of the stud in the slot, the height 
 of the slotting-bar will be correspondingly changed in 
 relation to the work-table of the machine. In effect 
 the stud may be considered as a fixed point by which 
 the bar is suspended, and consequently by turning the 
 hand-wheel of the screw in one direction or other, the 
 bar will be correspondingly elevated or depressed, 
 and the tool thereby set at any height above the 
 table that may be necessary for the kind of work 
 ULder operation. And when it is so adjusted, the stud 
 is made fast in its place by tightening the pinchiug- 
 n it on the screwed tail projecting in front of the bar, 
 as above described. 
 
 The lower end of the connecting-rod O is flexibly attached by a stud-bolt to the disk or crank-wheel 
 N, which has a radial dovetail groove a formed in its plane face to receive the correspondingly formed 
 head of the bolt. This bolt or stud is embraced by a strong ferule of slightly greater length than the 
 eye of the connecting-rod, which fits upon it freely ; and being in its place, a large nut is passed upon 
 the projecting end of the bolt, which fixes the ferule between it and the edges of the groove in the face 
 
 3340. 
 
SLOTTING MACHINE. 
 
 633 
 
 of the wheel, and thereby effectually secures the stud in the required position, while the connecting-rou 
 is left free to revolve on the ferule, in consequence of the latter being slightly greater in length than 
 the eye of the rod. The position of the stud in relation to the centre of the crank-wheel obviously de 
 termines the length of the stroke of the slotting-bar. Thus, the wheel admits of the stud being fixea 
 at seven and a half inches from the centre as a maximum, and therefore the utmost throw will be tjf 
 teen inches. 
 
 formed in halves, to admit of their being adjusted, as they wear, by cotters acting against the under 
 
034 
 
 SLOTTING MACHINE. 
 
 brasses, as shown in the side elevation of the machine. On the opposite end of the crank-wheel shaf 1 
 is keyed the spur-wheel G, which geers with the pinion H on the driving-shaft. The cone-pulley K 
 receives motion by a strap from the main shaft, and is susceptible of three modifications of speed, to 
 suit the kind of work under operation, the fly-wheel I rendering the motion uniform, and obviating the 
 jerks and variations to which it would otherwise be liable. This shaft lias one of its bearings in the 
 columnar frame of the machine, while the other is independently supported by a pillow resting on the 
 solo of a wall recess. 
 
 The sliding-table D is movable on the upper surface of the bed-plate E, in a direction parallel to tne 
 sole-frame of the machine ; and the circular table C is capable of sliding horizontally on this last, in a 
 direction at right angles to the direction of motion of the table D. From the sectional view, Fig. 8340, 
 it will be observed that the table 0 is provided with a rectangular sole-plate, to which it is attached 
 by a central stud and socket, in such a manner as to be capable of working freely on the stud as on an 
 axis. By this arrangement two motions of the upper table are obtained, one rectilineal and the other 
 circular. The rectilineal motion is obtained from the sole-plate, on which are bevelled ledges, adjusted 
 to slide in corresponding faces formed on the table D, as shown in Fig. 3388 ; and the circular motion 
 is obtained by causing the upper plate to revolve on its centre. The first of these motions is commu- 
 nicated by means of a screw e , which passes through a longitudinal recess, formed for its reception in 
 the table D, and works into a nut attached to the sole-plate of ihe upper table. To obtain the circular 
 motion, the table C is formed with a worm-wheel on its circumference, into which the worm on the 
 spindle S geers ; and as this spindle is attached by its bearings to the rectangular sole-plate, whici 
 cannot revolve in consequence of its attachment to the table D, it is obvious that by turning the crank 
 handle on the worm-spindle, the plate C will be made to revolve on its central stud. 
 
 The table D can also be worked by hand, by placing a crank-handle on the square end of the screw h, 
 the self-acting mechanism to be described presently being out of geer. This screw has its bearings in 
 the bed plate E, and works in a nut attached to the under side of the table. It may also be observed 
 that one of the dovetail or bevelled ledges of each of the sliding-tables is adjustable by set-screws when 
 reduced by wearing, as shown in the section of the table D. 
 
 A self-acting motion may be given to the under table by means of an arrangement of parts shown in 
 the side elevation of the machine. These consist of the ratchet-wheel L, which is keyed upon the end 
 of a spindle connected by a universal joint at M, with the screw h ; and a pawl l, attached to the end of 
 the lever m , on the same axis and formed of a piece with the lever n. In one arm of the wheel G is 
 fixed a stud o, carrying a small friction pulley, and adjustable, like the stud in the crank-wheel, to any 
 required distance from the centre. This stud, as the wheel revolves, comes in contact with the lever n, 
 which, being loose on its axis, yields to the pressure, and through the lower arm m , and pawl l, trans- 
 mits its motion to the ratchet-wheel, and through this again to the screw h. The pawl l can be applied 
 to either side of the ratchet-wheel, so that the table may be made to travel upon the bed E, in either 
 direction, and as the throw of the lever n can be regulated by the position of the stud o, the amount of 
 the feed motion may thus be adjusted to the kind of work. The object of the universal joint at M is to 
 permit the table to be set at a small angle with the horizontal plane, when necessary, as in cutting the 
 key-seats of wheels. This is effected by raising the inner end of the table by means of the screwed 
 link b, jointed to the bed-plate E, as shown in Fig. 3340, and acted upon by the set-nuts marked 2, 2, 
 shown in the side elevation of the machine. The bed-plate of the table, when in this position, is sup- 
 ported by two palms fitted to a cylindrical piece formed on the front of the main sole ; and is prevented 
 from moving laterally by the set-screws g g. 
 
 The circular motion of the table 0 may be communicated by the handle on the end of the worm- 
 spindle S ; but, to render it self-acting, a double ratchet-wheel is substituted for the handle, and is 
 worked by pawls attached to a rocking-lever, which communicates by a series of small rods with the 
 lever in. The transverse motion of the upper table can also be given by the handle on the end of the 
 screw e ; but a ratchet may also be substituted for this handle, and worked by a pawl connected with 
 the levers employed to transmit the circular motion of the table. Thus each and all of the three mo- 
 tions of the table may be rendered self-acting, and the work thereby carried on independently of that 
 constant attention which would otherwise be requisite on the part of the workman. It is seldom, how- 
 ever, that more than one of the self-acting motions is required to be in action at a time, the other mo- 
 tions being adjusted by hand. 
 
 Literal References. 
 
 A, the frame of the machine. 
 
 B, the slotting-bar. 
 
 a, dovetail groove in the crank-wheel N. 
 
 0, the circular table upon which the work is fixed. 
 
 D, the under slide of the table. 
 
 E, the bed-plate of this slide. 
 
 b, a fink with adjusting nuts for setting the work- 
 table at an angle. 
 
 e, guide-screw of the upper table, 
 o g, set-screws for preventing lateral motion of the 
 table. 
 
 h, guide screws of the lower table. 
 
 G, spur-wheel on the crank-wheel shaft, geering 
 with 
 
 H, a pinion on the driving-shaft. 
 
 1, fly-wheel on the driving-shaft. 
 
 ' K, cone-pulley for driving the machine. 
 
 j L, a ratchet-wheel by which motion is transmitted 
 to the slide-screw h. 
 
 l, a pawl for working the wheel L. 
 
 m, lower arm of the lever to which the pawl is at- 
 tached. 
 
 n, upper arm of the same lever receiving motion 
 from the stud o. 
 
 | M, a universal joint by which the spindle of the 
 ratchet-wheel L is connected to the screw h. 
 
 N, the crank-wheel on the main shaft. 
 
 O, the connecting-rod to the slotting-bar. 
 
 i P, hand-wheel on the screw for adjusting the stroke 
 of the machine. 
 
 j S, the spindle of the worm geering w.tb the worm- 
 
 1 wheel on the table 0 
 
SMUT MACHINE. 
 
 635 
 
 SLUICE-COCKS, Waller’s Patent. This invention consists in applying movable bushes or facings to 
 sluice-cocks, and in constructing the bushes in such a manner that they shall be harder, and fit more 
 truly, and may be more readily applied and replaced when worn ; it further consists in a mode of render- 
 ing the working surfaces of sluice-cocks, which are made without movable bushes, more hard and durable 
 Fig. 3341 is a vertical section of the improved sluice-cock ; Fig. 3342 also represents a vertical sec 
 tion, taken on the line AB of Fig. 3341 ; and Fig. 3343 is a horizontal section taken on the line CD oi 
 Figs. 3341 and 3342. a is the body of the cock, and b b are portions of two pipes which enter the 
 sockets of the cock, and are retained therein water-tight by the application of melted lead, in the 
 usual manner. The body of the cock is bored out, and the backs of the bushes cc are turned 
 in a lathe, so as to fit the recesses thus formed. The bushes are made, by preference, of cast-iron, 
 (although other metal may be used ;) the working surfaces are chilled in the act of casting, and art 
 ground or “ faced lip” with emery in a lathe. The bushes are coated on their backs with marine glue. 
 
 or similar material, previous to introducing them into the co< 't ; and after the bushes have been intro- 
 duced into the cock, they are moved back in the recesses before mentioned, into a proper working posi- 
 tion by forcing down the plug d into its place. The patentee does not confine himself to the shape oi 
 the recesses formed in the body of the cock, as that may be varied, e is a screw for raising and lower- 
 ing the plug; / is a screw-nut, fitted into a recess at the top of the plug; <j g are ribs, formed on the 
 interior of the upper part of the cock ; and k h are corresponding ribs on the outer surface of the upper 
 part of the plug ; the use of the ribs being to guide the plug correctly in its movement up and down. 
 The surfaces of the plug are chilled in the act of casting, and are then ground with emery. 
 
 When making sluice-cocks without movable bushes, the patentee causes the surface against which 
 the plug works to be chilled in the act of casting the body of the cock, so as to make it more durable , 
 and this surface is afterwards rendered true by means of a revolving tool and emery. 
 
 The patentee claims, Firstly, the mode of preparing the bodies of sluice-cocks with recesses for 
 receiving bushes ; the planes of the surfaces being inclined to the central line of the barrel of the 
 cock as above described. Secondly — the mode of applying movable bushes to cocks. Thirdly — mak- 
 ing the movable bushes, and also the plugs of sluice-cocks, with chilled working surfaces as described. 
 Fourthly — the making of sluice-cocks with chilled surfaces, which form the bed of the plug. 
 
 SMUT MACHINE. F. Harris efe Sons’ Patent Smut and Scouring Machine, for cleaning aP kinds 
 
 cl grain, was, we understand, originally invented for hulling and pearling rice and coffee, as also foi 
 Eiuutting and polishing wheat and other grain. It has been in successful operation for several years 
 
636 
 
 SOLDERING. 
 
 past, giving entire satisfaction to all who have used it, and acknowledged to be superior for cleaning 
 and scouring grain — being capable (when set the right distance apart) of pearling barley and wheat 
 with ease. 
 
 This machine is constructed of three concave and convex stones, of a very porous and gutty nature, 
 dressed similar to a mill-stone, are equally as durable, with a perforated iron case around the running 
 or concavo-convex stone, (which makes 400 revolutions per minute,) all set into a frame, as repre- 
 sented in Fig. 8344, with a perpendicular blower or fan attached to the spindle, capable of blowing 
 every thing from the grain without a particle of waste. 
 
 This machine is capable of cleaning from 10 to 80,000 bushels of grain previous to being dressed or 
 picked, which makes it do the work as well as when first put in operation. The stones can be set as 
 necessity requires, closer or further apart, so as to suit all kinds of grain, and are well adapted for 
 custom mills. 
 
 SOLDERING. Soldering is the process of uniting the edges or surfaces of similar or dissimilar met- 
 als and alloys by partial fusion. In general, alloys or solders of various and greater degrees of fusi- 
 bility than the metals to be joined, are placed between them, and the solder when fused unites the threa 
 parts into a solid mass ; less frequently the surfaces or edges are simply melted together with an addi- 
 tional portion of the same metal. 
 
 The circumstances to be considered in respect to soldering, are, for the most part, that the solders 
 must be necessarily somewhat more fusible than the metals to be united ; and that it is of primary im- 
 portance that the metallic oxides and any foreign matters be carefully removed, for which purpose the 
 edges of the metals are made chemically clean, or quite bright, before the application of the solders and 
 heat ; and as during this period their affinity for oxygen is violent, they are covered with some flux 
 which defends them from the air, as with a varnish, and tends to reduce any portion of oxide accident- 
 ally existing. 
 
 The solders are broadly distinguished as hard-solders and soft-solders ; the former only fuse at the 
 red heat, and are consequently suitable alone to metals and alloys which will endure that temperature; 
 the soft-solders melt at very low degrees of heat, and may be used for nearly all the metals. 
 
 The attachment is in every case the stronger the more nearly the metals and solders respectively 
 agree in hardness and malleability. Thus, if two pieces of brass or copper, or one of each, are brazed 
 together, or united with spelter solder, an alloy nearly as tough as the brass, the work may be ham- 
 mered, bent, and rolled, almost as freely as the same metals when not soldered, because of the nearly 
 equal cohesive strength of the three parts. 
 
 Lead, tin, or pewter, united with soft-solder, are also malleable from the near agreement of these sub- 
 stances ; whereas when copper, brdss, and iron are soft-soldered, a blow of the hammer or any accidental 
 violence, is almost certain to break the joint asunder, so long as the joint is weaker than the metal gen- 
 erally ; and therefore the joint is only safe when the surrounding metal from its thinness is no stronger 
 than the solder, so that the two may yield in common to any disturbing cause. 
 
 When the spaces between the works to be joined are wide and coarse, the fluid solder will probably 
 fall out, simply from the effect of gravity ; but when the crevices are fine and close, the solder will be 
 as it were sucked up by capillary attraction. All soldered works should be kept under motionless re- 
 straint for a period, as any movement of the parts during the transition of the solder from the fluid tc 
 the solid state, disturbs its crystallization and the strict unity of the several parts. 
 
 In hard-soldering it is frequently necessary to bind the works together in their respective positions ; 
 this is done with soft iron binding wire, which for delicate jewelry work is exceedingly fine, and for 
 stronger works is the twentieth or thirtieth of an inch in diameter ; it is passed round the work in loops, 
 the ends of which are twisted together with the pliers. The Asiatics seldom use binding wire. 
 
 In soft-soldering the binding wire is scarcely ever used, as from the moderate and local application 
 of the heat, the hands may in general be freely used in retaining most thin works in position during the 
 process. Thick works are handled with pliers or tongs whilst being soft-soldered, and they are often 
 treated much like glue joints, if w r e conceive the wood to be replaced by metal, and the glue by solder, 
 as the two surfaces are frequently coated or tinned whilst separated, and then rubbed together to dis- 
 tribute and exclude the greater part of the solder. 
 
 The succeeding “ Tabular View of the Processes of Soldering” may be considered as the index to the 
 entire subject; which refers to the ordinary methods of soldering most metals. The article is arranged 
 under three divisions, illustrated in distinct sections, preceded by one section on the modes of applying 
 heat 
 
 Tabulae view of the processes of soldephng. — To avoid continual repetition, references are made tc 
 the lists on the succeeding page, in -which some of the solders, fluxes, and modes of applying heat are 
 enumerated. 
 
 Hard soldering. — Applicable to nearly all metals less fusible than the solders ; the modes of treat- 
 ment nearly similar throughout. 
 
 The hard-solders most commonly used are the spelter solders and silver solders. The general flux is 
 borax marked A, on next page ; and the modes of heating are the naked fire, the furnace or muffle, and 
 the blowpipe, marked a, b , g. 
 
 Note. — The examples commence with the solders, (the least fusible first,) followed by the metals for 
 which they are commonly employed. 
 
 Fine gold, laminated and cut into shreds, is used as the solder for joining chemical vessels made ol 
 platinum. 
 
 Silver is by many considered as much the best solder for German silver. 
 
 Copper in shreds is sometimes similarly used for iron. 
 
 Gold solders laminated are used for gold alloys. 
 
 Spelter solders, granulated whilst hot, are used for iron, copper, brass, gun-metal, German silver, (fee, 
 
 Silver solders laminated are employed for all silver works and for common gold work, also for Ger- 
 
SOLDERING. 
 
 637 
 
 man silver, gilding metal, iron, steel, brass, gun-metal, Ac., -when greater neatness is required than is ob- 
 tained with spelter solder. 
 
 White or button solders granulated are employed for the white alloys called button metals ; they 
 were introduced as cheap substitutes for silver solder. 
 
 Soft-soldering . — Applicable to nearly all the metals ; the modes of treatment very different. 
 
 The soft-solder mostly used is 2 parts tin and 1 part lead ; sometimes from motives of economy much 
 more lead is employed, and 1-J tin to 1 lead is the most fusible of the group unless bismuth is used, 
 The fkixes B to G-, and the modes of heating, a to i, are all used with the soft-solders. 
 
 Note. — T he examples commence with the metals to be soldered. Thus in the list, zinc, 8, C, f im- 
 plies that zinc is soldered with No. 8 alloy, by the aid of the muriate or chloride of zinc and the copper 
 bit. Lead, 4 to 8, F, d, e, implies that lead is soldered with alloys varying from No. 4 to 8, and that 
 it is fluxed with tallow, the heat being applied by pouring on melted solder, and the subsequent use of 
 the heated iron not tinned ; but in general one only of the modes of heating is selected, according to cir- 
 cumstances. 
 
 Iron, cast-iron, and steel, 8, B, D, if thick, heated by a, b, or c, and also by g. 
 
 Tinned iron, 8, C, D ,/. 
 
 Silver and gold are soldered with pure tin or else with 8, E, a, g, or li. 
 
 Copper and many of its alloys, namely, brass, gilding metal, gun-metal, Ac., 8, B, C, D ; when thick, 
 heated by a, b , c, e, or g, and when thin by f or g. 
 
 Speculum metal, 8, B, C, D, the heat should be most cautiously applied ; the sand-bath is perhaps the 
 best mode. 
 
 Sine, 8 0,/ 
 
 Lead and lead pipes, or ordinary plumbers’ work, 4 to 8, F, d, or c. 
 
 Lead and tin pipes, 8 D and G mixed, g, and also/. 
 
 Britannia metal, 8, C, D, g. 
 
 Pewters : the solders must vary in fusibility according to the fusibility of the metal, generally G and 
 i are used, sometimes also G and g, or / 
 
 Tinning the metals, and washing them with lead, zinc, <fcc. 
 
 Soldering per se, or burning together. — Applicable to some few of the metals only, and which in gen- 
 eral require no flux. 
 
 Iron, brass, Ac., are sometimes burned, or united by partial fusion, by pouring very hot metal over 
 or around them, d. 
 
 Lead is united without solder, by pouring on red-hot lead, and employing a red-hot iron, d, e, and 
 also by the autogenous process. 
 
 Alloys and their Melting Heats* Fluxes. 
 
 ). 1. 
 
 1 Tin, 
 
 25 Lead 
 
 558 Fahr. 
 
 A. Borax. 
 
 2. 
 
 1 “ 
 
 10 “ 
 
 .... 541 “ 
 
 B. Sal-ammoniac, or muriate of ammonia. 
 
 8. 
 
 1 “ 
 
 5 “ 
 
 .... 511 “ 
 
 C. Muriate, or chloride of zinc. 
 
 4. 
 
 1 “ 
 
 3 “ 
 
 .... 482 “ 
 
 D. Common resin. 
 
 5. 
 
 1 “ 
 
 2 “ 
 
 .... 441 “ 
 
 E. Venice Turpentine. 
 
 6. 
 
 1 “ 
 
 i “ 
 
 
 F. Tallow. 
 
 7. 
 
 14 “ 
 
 i “ 
 
 .... 334 “ 
 
 G. Gallipoli oil, a common sweet oil. 
 
 8. 
 
 2 “ 
 
 i “ 
 
 .... 340 “ 
 
 
 9. 
 
 3 “ 
 
 i “ 
 
 .... 356 “ 
 
 Modes of Applying Heat. 
 
 10. 
 
 4 “ 
 
 i “ 
 
 .... 365 “ 
 
 a. Naked fire. 
 
 11. 
 
 5 “ 
 
 i “ 
 
 .... 378 “ 
 
 b. Hollow furnace or muffle. 
 
 12. 
 
 6 “ 
 
 i “ 
 
 .... 381 “ 
 
 c. Immersion in melted solder. 
 
 13. 
 
 4 Lead, 4 Tin, 1 Bismuth .... 
 
 .... 320 “ 
 
 d. Melted solder or metal poured on. 
 
 14. 
 
 3 “ 
 
 3 “ 1 
 
 .... 310 “ 
 
 c. Heated iron not tinned. 
 
 15. 
 
 2 “ 
 
 2 “ 1 
 
 .... 292 “ 
 
 /. Heated copper tool, tinned. 
 
 16. 
 
 i “ 
 
 1 “ 1 
 
 .... 254 “ 
 
 g. Blowpipe flame. 
 
 17. 
 
 2 “ 
 
 1 “ 2 “ 
 
 .... 236 « 
 
 h. Flame alone, generally alcohol. 
 
 18. 
 
 3 “ 
 
 5 “ 3 
 
 .... 202 “ 
 
 i. Stream of heated air. 
 
 The modes of applying heat in soldering. — The modes of heating works for soldering are extremelv 
 varied, and depend jointly upon the magnitude of the objects, the general or local manner in which they 
 are to be soldered, and the fusibility of the solders. It appears to be now desirable to advert to sue! 
 of the modes of applying heat enumerated in the tabular view, as are of more general application, leav- 
 ing the modes specifically employed in heating works to their respective sections. 
 
 In hard-soldered works, the fires bear a general resemblance to those employed in forging iron ana 
 steel ; in fact, the blacksmith’s forge is frequently used for brazing, although the process is injurious to 
 the fuel as regards its ordinary use. Coppersmiths, silversmiths, and others, use a similar hearth, but 
 which stands further away from the upright wall, so as to allow of the central parts of large objects 
 being soldered ; the bellows are always worked by the foot, either by a treadle, or more commonly by 
 a chain from the rocking-staff terminating in a stirrup. 
 
 The brazier’s hearth for large and long works, is a flat plate of iron, about four feet by three, which 
 stands in the middle of the shop upon four legs : the surface of the plate serves for the support of long 
 tubes and works over the central aperture in the plate which contains the fuel, and measures about 
 
 * By the addition of 3 parts of mercury to No. 18 it melts at 122° F., and may be used for anatomical injections and fee 
 Hopping teeth. 
 
SOLDERING. 
 
 bi 8 
 
 twc feet by one, and five or six inches deep. The revolving fan is commonly used for the blast, and 
 the tuyere irons, which have larger apertures than usual, are fitted loosely into grooves at the ends, to 
 admit of easy renewal, as they are destroyed rather quickly. The fire is sometimes used of the full 
 length of the hearth, but is more generally contracted by a loose iron plate ; occasionally two separate 
 fires are made, or the two blast-pipes are used upon one. The hood is suspended from the ceiling, with 
 counterpoise weights, so as to be raised or depressed according to the magnitude of the works ; and it 
 has large sliding tubes for conducting the smoke to the chimney. 
 
 Furnaces are occasionally used in soldering, or the common fire is temporarily converted into the con- 
 dition of a furnace from being built hollow, or by the insertion of iron tubes or muffles amidst the ignited 
 fuel, as already explained in reference to forging and hardening. For want of any of these means, the 
 amateur may use the ordinary grate, or it is better to employ a brazier or chafing-dish containing char- 
 coal, and urged with hand-bellows blown by an assistant, as then both hands are at liberty to manage 
 the work and fuel. 
 
 Fresh coals are highly improper for soldering on account of the sulphur they always contain ; the 
 best fuel is charcoal, but in general coke or cinders are used. Lead is equally as prejudicial to the fire 
 in soldering as it is in welding iron and steel, or in forging gold, silver, or copper ; as the lead readily 
 oxidizes and attaches itself to the metals that are being soldered or welded, preventing the union of the 
 parts, and in almost all cases rendering the metals brittle and unserviceable. 
 
 There are many purposes in the arts which require the application of heat having the intensity of 
 the forge-fire or of the furnace, but with the po-wer of observation, guidance, and definition of the artist’s 
 pencil. These conditions are most efficiently obtained by the blowpipe, an instrument by which a stream 
 of air is driven forcibly through a flame, so as to direct it either as a well-defined cone, or as a broad 
 jet of flame, against the object to be heated, which is in many cases supported upon charcoal, by way 
 of concentrating the heat. 
 
 The blowpipe is largely used — namely, in soldering, in hardening and tempering small tools, in glass- 
 blowing for philosophical instruments and toys, in glass-pinching with metal moulds made like pliers, 
 in enamelling, and by the chemist and mineralogist, as an important means of analysis : the instrument 
 has consequently received very great attention both from artisans and distinguished philosophers. 
 
 Most of the blowpipes are supplied with common air, and generally by the respiratory organs of the 
 operator ; sometimes by bellows moved with the foot, by vessels in which the air is condensed by a 
 syringe, or by pneumatic apparatus with water pressure. In some few cases oxygen or hydrogen, or the 
 same gases when mixed, are employed ; they are little used in the arts. 
 
 The ordinary blowpipe is a light conical brass tube, about 10 or 12 inches long, from one-half to one- 
 fourth of an inch diameter at the end for the mouth, and from one-sixteenth to one-fiftieth at the aper- 
 ture or jet ; the end is bent as a quadrant, that the flame may be immediately under observation. 
 
 The lungs may be used for the blowpipe with much more effect than might be expected, and with a 
 little practice a constant stream may be maintained for many minutes if the cheeks are kept fully dis- 
 tended with wind, so that their elasticity alone shall serve to impel a part of the air, whilst the ordinary 
 breathing is carried on through the nostrils for a fresh supply. 
 
 The. most intense heat of the common blowpipe is that of the pointed flame ; with a thick wax can 
 die, and a blowpipe with a small aperture placed slightly within the flame, the mineralogist succeeds 
 in melting small fragments of all the metals, when they are supported upon charcoal and exposed to 
 the extreme point of the inner or blue cone, which is the hottest part of the flame ; that is, fragments of 
 all metals which do not require the oxyhydrogen blowpipe. 
 
 Larger particles, requiring less heat, are brought somewhat nearer to the candle, so as to receive a 
 greater portion of the flame ; and when a very mild degree of heat is needed, the object is removed fur- 
 ther away, sometimes as in melting the fluxes preparatory to soldering, even to the stream of hot air 
 beyond the point of the external yellowish flame. 
 
 The first, or the silent pointed flame, is used by the chemist and mineralogist for reducing the metal- 
 lic oxides to the metallic state, and is called the deoxidizing flame ; the second, or the noisy, brush-like 
 flame, is less intense, and is called the oxidizing flame. 
 
 The artisan employs in soldering a much larger flame than the chemist, namely, that of a lamp the 
 wick of which is from a quarter to one inch diameter: this must be plentifully supplied with oil ; the 
 blowpipe in such cases is selected with a larger aperture, it is blown vigorously, and held a little distant 
 from the flame, so as to spread it in a broad stream of light, extending over a large surface of the work, 
 which is in most cases supported upon charcoal. When any minute portion alone is to be heated, the 
 pointed flame is used, with a milder blast of air and a decreased distance. 
 
 The following method is much employed by the cheap jewelry manufacturers at Birmingham. A 
 6tream of air from a pair of bellows directs a gas flame through a trough or shoot, the third of a cylin- 
 drical tube placed at a small angle below the flame. Instead of a charcoal support they employ a 
 wooden handle, upon which is fixed a flat disk of sheet-iron, about three or four inches diameter, covered 
 witli a matting of waste fragments of binding wire, entangled together and beaten into a sheet about 
 throe-eighths or half an inch thick ; some few of the larger pieces of wire extend round the edge of the 
 disk to attach the remainder. The work to be soldered is placed upon the wire, which becomes par- 
 tially red-hot from the flame, and retains the heat somewhat as the charcoal, but without the inconve- 
 nience of burning away, so that the broad level surface is always maintained. Small cinders are fre- 
 quently- placed, upon the tool, either instead of, or upon the wire. 
 
 Sometimes the gas-pipe is surmounted by a square hood, open at both ends, and two blast-pipes are 
 directed through it ; the latter arrangement is used by the makers of glass toys and seals ; these are 
 pinched in moulds something like bullet-moulds ; the devices on the seals are produced by inserting in 
 the moulds dried casts, made in plaster of Paris. 
 
 Makeis of thermometers and other philosophical instruments generally use a table blowpipe, with a 
 thallow oval, or rather a kidney-shaped lamp, with a loop placed lengthways upon the short diametei 
 
SOLDERING. 
 
 689 
 
 • : 
 
 for holding the cotton, -which is sometimes an inch long and half an inch wide. The wick is plentifully 
 supplied with tallow or hog’s lard, and a furrow is made through it with a wire to afford a free passage 
 for the blast from the fixed nozzle, by the size of which, and its distance from the flame, the latter is 
 made to assume the pointed or brush-like character. This lamp is more cleanly, and emits less smell 
 than those supplied with oil ; any overflow of the tallow is caught in the outer vessel or tray, and when 
 cold, the fat solidifies. 
 
 Many blowpipes have been invented for the employment of oxygen and hydrogen ; the mixed gases 
 were first used by Dr. Hare, of Philadelphia, who has been followed in various ways by Clark, Gurney, 
 CummiDg, Hemming, Marcet, Leeson, and many others. Two subsequent modifications of gas blow- 
 pipes which have been invented for the workshop will alone be here described, namely, Sir John Rob- 
 ison’s Workshop Blowpipe, intended for soldering, hardening, and other purposes; and the Count de 
 Richemont’s Airo-hydrogen Blowpipe. 
 
 The general form of the “ workshop blowpipe” is that of a tube open at the one end, and supported 
 on trunnions in a wooden pedestal, so that it may be pointed vertically, horizontally, or at any angle as 
 desired. Common street gas is supplied through the one hollow trunnion, and it escapes through an 
 annular opening ; whilst oxygen gas, or more usually common air, is admitted through the other trun- 
 nion which is also hollow, and is discharged in the centre of the hydrogen through a central conical tube ; 
 the magnitude and intensity of the flame being determined by the relative quantities of gas and air, and 
 by the greater or less protrusion of the inner cone, by which the annular space for the hydrogen is con- 
 tracted in any required degree. 
 
 Prom amongst numerous other small applications of heat, Mr. Gill’s portable blowpipe furnace may 
 be noticed ; it consists of a lump of pumice-stone three or four inches diameter, scooped out like a pan 
 or crucible, and filled with small fragments of charcoal ; sometimes a conical perforated cover is added ; 
 the inside may be intensely ignited, whilst the slow conducting power of the pumice-stone guards the 
 hand from inconvenient heat. 
 
 Examples of hard-soldering. — It was mentioned in the tabular view that the several works united 
 with hard-solders receive nearly the’ saine treatment ; a few examples will therefore serve to convey a 
 general idea of hard-soldering — a process commonly attended with some risk of partially melting the 
 works, because the fusing points of the metals and their respective solders often approach very nearly 
 together. 
 
 Several of the hard-solders contain zinc, which appears to be useful in different ways : first, it in- 
 creases their fusibility ; in cases where the solder cannot be seen it serves as an index to denote the 
 completion of the process, for when the solder is melted the zinc volatilizes, and burns with the well- 
 known blue flame ; and as at this moment some of the zinc is consumed, the alloy left behind becomes 
 tougher, and more nearly approaches to the condition of the metal which it is desired to unite. The 
 zinc may be therefore considered to act as a flux, and so likewise does the arsenic occasionally intro- 
 duced into the gold and silver solders, as the arsenic is for the most part lost between the processes of 
 making and using the solders ; but this metal being of a noxious quality, it is but little resorted to, and 
 besides, it renders the other metals very brittle. 
 
 In every case of soldering, a general regard to cleanliness in the manipulation is important, and for 
 the most part the edges of the metals are filed or scraped prior to their being soldered, as before ob- 
 served; in those cases in which the red-heat is employed, filing or scraping are less imperative, as any 
 greasy or combustible matters are burned away, and the borax has the property of combining with 
 nearly all the metallic oxides and earthy bases, thereby cleansing the edges of the metals, should that 
 proceeding have been previously omitted. 
 
 The works in copper, iron, brass, &c., having been prepared for brazing, (or soldering with a fusible 
 brass,) and the joints secured in position by binding wire where needful, the granulated spelter and 
 pounded borax are mixed in a cup with a very little water, and spread along the joint by a slip of sheet- 
 metal or a small spoon. 
 
 The work, if sufficiently large, is now placed above the clear fire, first at a small distance so as grad- 
 ually to evaporate the moisture, and likewise to drive off the water of crystallization of the borax; dur- 
 ing this process the latter boils up with the appearance of froth or snow, and if hastily heated it some- 
 times displaces the solder. The heat is now increased, and when the metal becomes faintly red, the 
 borax fuses quietly like glass ; shortly after, that is at a bright red, the solder also fuses, the indication 
 of which is a small blue flame from the ignition of the zinc. Just at this time some works are tapped 
 slightly with the poker to put the whole in vibration, and cause the solder to run through the joint to 
 the lower surface, but generally the solder flushes, or is absorbed in the joint, and nearly disappears 
 without the necessity for tapping the work. 
 
 It is of course necessary to apply the heat as uniformly as possible by moving the work about so as 
 to avoid melting the object as well as the solder; the work is withdrawn from the fire as soon as the 
 solder has flushed, and when the latter is set, the work may be cooled in water without mischief. 
 
 Tubes are generally secured by loops of binding wire twisted together with the pliers ; and those sol- 
 dered upon the open fire are almost always soldered from within, as otherwise the heat would have to 
 be transmitted across the tube with greater risk of melting the work, air being a bad conductor of heat ; 
 it is necessary to look through the tube to watch for the melting of the solder. Long tubes are rested 
 upon the flat plate of the brazier’s hearth, and portions equal to the extent of the fire are soldered in 
 succession. The common Birmingham tubes for gas-works, bedsteads, and numerous other purposes, 
 are soldered from the outside ; but this is done in short furnaces open at both ends and level with the 
 floor, by which the heat is applied more uniformly around the tubes. 
 
 Works in iron require much less precaution in point of the heat, as there is little or no risk of fusion ; 
 thus in soldering the spiral wires to form the internal screw within the boxes of ordinary tail-vices, the 
 work is coated with loam, and strips of sheet-brass are used as solder ; the fire is urged until the. blue 
 flame appears at the end of the tube when the fusion is complete : the work is withdrawn from the fire 
 
040 
 
 SOLDERING-. 
 
 5: 
 
 and rolled backwards and forwards on the ground to distribute the solder equally at every part. Other 
 common works in iron, such as locks, are in like manner covered with loam to prevent the iron from 
 scaling off. Sheet-iron may be soldered by filings of soft cast-iron, applied in the usual way of solder- 
 ing with borax, which has been gradually dried in a crucible and powdered, and a solution of sal-am- 
 moniac.” 
 
 The finer works in iron and steel, those in the light-colored metals generally, and also the works in 
 brass which are required to be very neatly done, are soldered with silver-solder. From the superior 
 fusibility of silver -solder, and from its combining so well with the different metals without “gnawing 
 them or eating them away" or wasting part of the edges of the joints, silver-solder is very desirable for 
 a great many cases ; and from the more careful and sparing manner in which it is used, many objects 
 require but little or no finishing subsequently to the soldering, so that the more expensive solder is not 
 only better, but likewise in reality more economical. 
 
 The practice of silver-soldering is essentially the same as brazing. The joint is first moistened with 
 borax and water ; the solder, (which is generally laminated and cut into little squares with the shears,) 
 is then placed on the joint with forceps. In heating the work additional care is given not to displace 
 the solder; and for which reason some persons boil the borax, or drive off its water of crystallization at 
 the red-heat, then pulverize it and apply it in the dry state along with the solder ; others fuse the borax 
 upon the joint before putting on the solder. 
 
 Numerous small works united with hard-solders, such as mathematical and drawing instruments, but- 
 tons, and jewelry, are soldered with the blowpipe ; in almost all cases the work is supported upon char- 
 coal, and sometimes for the greater concentration of the heat it is also covered with charcoal. The 
 management of the blowpipe having been explained, it is only necessary to add that the magnitude and 
 shape of the flame are proportioned to those of the works. 
 
 In soldering gold and silver the borax is rubbed with water upon a slate to the consistence of cream, 
 and is laid upon the work with a camel's hair pencil, and the solders although generally laminated are 
 also drawn into wire or filed into dust ; but it will be remembered, the more minute the particles of 
 the granulated metals the greater is the degree of heat required in fusing them. 
 
 In many of the jewelry works the solder is so delicately applied, that it is not necessary to file or 
 scrape off any portion, none being in excess, and the borax is removed by immersing the works in the 
 various pickling and coloring preparations. 
 
 Examples of soft-soldering. — In this section the employment of the less fusible of the soft-solders will 
 be first noticed ; the plumbers’ sealed-solder, 2 parts lead and 1 of tin, melts at about 440° F. ; the 
 usual or fine tin-solder, 2 parts tin and 1 of lead, melts at 340° ; and the bismuth-solders at from 250° 
 to 270° : the modes of applying the heat consequently differ very much, as will be shown. 
 
 The soft-solders are prepared in different forms suited to the nature of the various works. No. 5, p. 
 590, the plumber’s-solder, is cast in iron moulds into triangular ingots measuring from 1 to 6 superficial 
 inches in the section. No. 8, the fine tin-solder, is cast in cakes about 4 by 6 inches, and \ to J inch 
 thick ; and this and the more fusible kinds are trailed from the ladle upon an iron plate or flat stone, to 
 make slight bars, ribbons, and even threads, that the magnitude of the solder may be always propor- 
 tioned to the magnitude and circumstances of the work. 
 
 It is very essential that all soft-soldered joints should be particularly clean and free from metallic 
 oxides ; and except where oil is exclusively used as the flux, greasy matters should be avoided, as they 
 prevent the ready attachment of the aqueous fluxes. It is therefore usual with all the metals, except 
 clean tinned plate, and clean tin alloys, to scrape the edges immediately before the process, so far as 
 the solder is desired to adhere. 
 
 Lead works are first smeared or soiled around the intended joints with a mixture of size and lamp- 
 black, called soil, to prevent the adhesion of the melted solder ; next the parts intended to receive the 
 solder are shaved quite clean with the shave-hook, (a triangular disk of steel riveted on a wire stem,) 
 and the clean metal is then rubbed over with tallow. Some joints are wiped, without the employment 
 of the soldering-irou ; that is, the solder is heated rather beyond its melting point, and poured somewhat 
 plentifully upon the joint to heat it ; the solder is then smoothed with the cloth, or several folds of thick 
 bed-tick well greased, with which the superfluous solder is finally removed. 
 
 Other lead joints are striped, or left in ridges, from the bulbous end of the plumber’s crooked solder- 
 ing-iron, which is heated nearly to redness, and not tinned ; the iron and cloth are jointly used at the 
 commencement for moulding the solder and heating the joint. In this case less solder is poured on, and 
 a smaller quantity remains upon the work; and although the striped-joints are less neat in appearance, 
 they are by many considered sounder from the solder having been left undisturbed in the act of cooling. 
 The vertical joints, and those for pipes, whether finished with the cloth or iron, require the cloth to sup- 
 port the fluid solder when it is poured on the lead. 
 
 Slight works in lead, such as lattices, requiring more neatness than ordinary plumbing, are soldered 
 with the copper-bit or copper-bolt ; they are pieces of copper weighing from three or four ounces to as 
 many pounds, riveted into iron shanks and fitted with wooden handles. All the works in tinned iron, 
 sheet-zinc, and many of those in copper and other thin metals, are soldered with this tool, frequently 
 misnamed a soldering-iron, which in general suffices to convey all the heat required to melt the more 
 fusible solders now employed. 
 
 If the copper-bit have not been previously tinned, it is heated in a small charcoal stove or otherwise 
 to a dull red, and hastily filed to a clean metallic surface ; it is then rubbed immediately, first upon a 
 tump of sal-ammoniac, and next upon a copper or tin plate, upon which a few drops of solder have been 
 placed ; this will completely coat the tool ; it is then wiped clean with a piece ot tow and is ready for 
 use. 
 
 In soldering coarse works, when their edges are brought together they are slightly strewed with pow 
 dered resin, or it is spread on the work with a small spoon; the copper-bit is held in the right hand, 
 the cake of solder in the left, and a few drops of the latter are melted along the joint at short intervals 
 
SOLDERING. 
 
 641 
 
 The iron is then used to heat the edges of the metal, both to fuse and to distribute the solder along the 
 joint, so as entirely to till up the interval between the two parts ; only a short portion of the joint, 
 rarely exceeding six or eight inches, is done at once. Sometimes the parts are held in contact with a 
 broad chisel-formed tool, or a hatchet stake, whilst the solder is melted and cooled, or a few distant 
 parts are first tacked together or united by a drop of solder, but mostly the hands alone suffice without 
 the tacking. 
 
 Two soldering-tools are generally used, so that whilst the one is in the hand the other may be reheat- 
 ing in the stove ; the temperature of the bit is very important ; if it be not hot enough to raise the edges 
 of the metal to the melting heat of the solder, it must be returned to the tire ; but unless by misman- 
 agement it is made too hot and the coating is burned off, the process of tinning the bit need not be re- 
 peated, it is simply wiped on tow on removal from the fire. If the tool be overheated it will make the 
 solder unnecessarily fluid, and entirely prevent the main purpose of the copper-bit, which is intended to 
 act both as a heating tool and as a brush, first to pick up a small quantity or drop from the cake of 
 solder which is fixed upright in a tray, and then to distribute it alone the edge of the joint. 
 
 The tool is sometimes passed only once slowly along the work, being guided in contact with the fold 
 or edge of the metal. This supposes the operator to possess that dexterity of hand which is abundantly 
 exhibited in many of the best tin wares ; in these the line of solder is very fine and regular. The sol- 
 dering-tool is then thin and keen on the edge, and the flux instead of being resin is mostly the muriate 
 of zinc, with which the joint is moistened by means of a small wire or a stick prior to the application of 
 the heated tool ; sometimes the workman cools the part just finished by blowing upon it as the bit pro- 
 ceeds in its course ; and the iron if overheated is cooled upon a moistened rag placed in' the empty 
 space of the tray containing the solder. 
 
 Copper works are more commonly fluxed with powdered sal-ammoniac, and so likewise sheet-iron, 
 although some mix powdered resin and sal-ammoniac ; others moisten the edges of the work with a satu- 
 rated solution of sal-ammoniac, using a piece of cane, the end of which is split into filaments to make a 
 stubby brush, and they subsequently apply resin : each method has its advocates, but so long as the 
 metals are well defended from oxidation any mode will suffice, and in general management the pro- 
 cesses are the same. 
 
 Zinc is more difficult to solder than the other metals, and the joints are not generally so neatly exe- 
 cuted ; the zinc seems to remove the coating of tin from the copper soldering-tool ; this probably arises 
 from the superior affinity of copper for zinc than for tin. The flux sometimes used for zinc is sal-ammo- 
 niac, but the muriate of zinc, made by dissolving fragments cf zinc in muriatic acid diluted with about 
 an equal quantity of water, is much superior ; and the muriate of zinc serves admirably likewise for all 
 the other metals, without such strict necessity for clean surfaces as when the other fluxes are used. 
 
 The copper tool is only applicable to thin metals, because it requires such a degree of heat as will 
 allow it to raise the temperature of the work to be joined to the melting point of the solder ; and the 
 excess of heat thus required for stout metals, is apt either to burn off the coating of solder, or to cause 
 it to be absorbed as a process of superficial alloying. It requires some tact to keep the heat of the tool 
 within proper limits by means of the charcoal or cinder fire, but with the airo-hydrogen blowpipe it is 
 easy to maintain any required temperature for an indefinite period. 
 
 Thicker pieces of metal, such as the parts of philosophical apparatus, gas-fittings, and others which 
 cannot be conveniently managed with the copper-bit, are first prepared by fifing or turning, and each 
 piece is then separately tinned in one of the following ways. Small pieces, immediately after being 
 cleaned with the file or other tool, and without being touched with the fingers, are dipped into a ladle 
 containing melted solder, which is covered with a little powdered sal-ammoniac. The flux meets the 
 work before it is subjected to the heat, and the tinning is then readily done ; sometimes the work is in 
 the first instance sprinkled with resin, or rubbed over with sal-ammoniac water ; the latter is rather a 
 dangerous practice, as the moisture is apt to drive the melted metal in the face of the operator. 
 
 Thin pieces of bx - ass or of copper alloys, if submitted to this method, must be quickly dipped, or their 
 is risk of their being attacked and partly dissolved by the solder. There is some little uncertainty as 
 to iron, and especially as to steel, being well coated by dipping; sometimes a forcible jar or a hard rub 
 will remove most of the tin, and it is therefore safer to rub these works with a piece of heated copper 
 shaped like a file, immediately on their removal from the melted solder, which makes the adhesion 
 more certain. 
 
 Larger pieces of metal, or those it is inconvenient to dip into the ladle, are first moistened with sal 
 ammoniac water, or dusted with the dry powder or resin, and heated on a clear fire either of charcoal, 
 coke, or cinders, until the strip of solder held against them is melted and adheres ; as the lowest heat 
 should be always used. Another cleanly way of applying the heat, and which is also employed in tem- 
 pering tools, varnishing, and cementing, is to make red-hot a few inches of the end of a flat iron bar 
 about two feet long, to pinch it in the vice by the cold part, and to lay the work upon that spot which 
 is at a suitable temperature ; the work can be thus very conveniently managed, especially as it may be 
 likewise placed in a good light. 
 
 Until the two parts of the work are thoroughly tinned, they must be well defended from the air by 
 the flux to prevent oxidation ; they are next made a trifle hotter than is required for tinning, and placed 
 in contact while the solder is quite fluid, and a little additional solder is also used ; when practicable, 
 the two surfaces are rubbed together to perfect the tinning and spread the alloy evenly' through the 
 joint, the work is then allowed to cool under pressure applied by the hammer handle, the blunt end of a 
 tool, the tail-vice, or in any convenient manner. The stages of this practice are similar to those of the 
 carpenter, who having brushed the glue over the two pieces of wood, rubs them together and fixes them 
 with the hand-screws until cold, as before adverted to. 
 
 Small works are sometimes united by cleaning the respective surfaces, moistening them with sal- 
 ammoniac water, or applying the dry powder or resin, then placing between the pieces a slip of tin 
 Vol. II. — 41 
 
642 
 
 SOLDERING. 
 
 foil, previously cleaned with emery-paper, and pinching the whole between a pair of heated tongs to 
 melt the foil ; or other similar modifications combining heat and pressure are used. 
 
 Many workmen who are accustomed to the blowpipe, as jewelers, mathematical instrument makers, 
 and others, apply the blowpipe with great success in soft-soldering ; but as the methods are in other 
 respects similar to those given, they do not require particular notice, except that in some cases there is 
 no choice but to tie the works together with binding wire, as in hard-soldering ; but the preference is 
 always given to detached tinning and rubbing together. 
 
 The modern gas-fitters are remarkably expert in joining tin and lead pipes with the blowpipe ; they 
 do not employ the method of the plumbers and pewterers, or the spigot and faucet joint surrounded by 
 a bulb of solder, but they cut off the ends of the pipes with a saw, and file the surfaces to meet in butt- 
 joints, in mitres, or in T-form joints, as required. In confined situations they apply the heat from one 
 side only with the blowpipe and rushes; they employ a rich tin-solder, with oil and resin mixed in 
 equal parts as the flux ; the work looks like carpentry rather than soldering. 
 
 An ingenious workman assured us that he had employed this mode, for lead pipes measuring 
 externally one inch and a half diameter and situated in angles, by placing pieces of slate against the 
 floor and the perpendicular partition to defend them from the flame, the action of which was assisted 
 by two pieces of charcoal inserted in the corners. And also that as a trial of skill, he had made fifteen 
 joints in three-quarter inch tin pipe, five of each kind, namely, plain, mitre, and T form, including the 
 preparations, in the exceedingly short period of twenty-five minutes. 
 
 Iron, copper, and alloys of the latter metal, are frequently coated with tin, and occasionally with lead 
 and zinc, to present surfaces less subject to oxidation ; gilding and silvering are partly adopted from 
 similar motives. 
 
 Copper and brass vessels are first pickled with sulphuric acid, mostly diluted with about three times 
 its bulk of water; they are then scrubbed with sand and water, washed clean and dried; they are next 
 sprinkled with dry sal-ammoniac in powder, and heated slightly over the fire ; then a small quantity of 
 melted block-tin is thrown in, the vessel is swung and twisted about to apply the tin on all sides, and 
 when it has well adhered the portion in excess is returned to the ladle, and the object is cooled in 
 water, When cleverly performed very little tin is taken up, and the surface looks almost as bright as 
 silver ; some objects require to be dipped into a ladle full of tin. 
 
 Iron presents rather more difficulty, the affinity of the tin being less strong for iron than for copper ; 
 but the treatment is in general nearly the same. Old works require that the grease should be removed 
 with concentrated muriatic acid, before the other processes are commenced ; and in cast-iron vessels the 
 grease often penetrates so deeply, owing to the porous nature of the metal, that the retinning is some- 
 times scarcely possible, and it is often more economical to obtain a new vessel. 
 
 An alloy of nickel, iron, and tin, has been introduced as an improvement in tinning the metals. 
 Mr. G. M. Braithwaite, one of the patentees, says that “ the nickel and tin compound is harder 
 than tin, and endures a much longer time ; it is less fusible, and will not run or melt at a heat that, 
 would cause the ordinary tinning of pans to forsake the sides and lie in a mass at the bottom. Also 
 that as an experiment to show the tenacity of the nickel, a piece of cast-iron tinned with the compound 
 had been subjected by him for a few minutes to the white heat under a blast, and although the tin was 
 consumed, the nickel remained as a permanent coating upon the iron.” 
 
 The proportions of nickel and iron mixed with the tin in order to produce the best tinning, are ten 
 ounces of the best nickel and seven ounces of sheet-iron to ten pounds of tin. These metals are mixed 
 in a crucible, and to prevent the oxidation of the tin by the high temperature necessary for the fusion of 
 the nickel, the metals are covered with one ounce of borax and three ounces of pounded glass. The 
 fusion is completed in about half an hour, when the composition is run off through a hole made in the 
 flux. In tinning metals with this composition the workman proceeds in the ordinary manner. 
 
 There is also another method, that of cold-tinning , by aid of the amalgam of mercury ; but this pro- 
 cess, when applied to utensils employed for preparing or receiving food, appears questionable both as 
 regards effectiveness and wholesomeness, and the activity of the muriatic acid must not be forgotten ; it 
 should be therefore washed carefully off with water. The tin adheres, however, sufficiently well to 
 allow other pieces of metal to be afterwards attached by the ordinary copper soldering-bit. 
 
 Soldering per se, or hurtling together. — This principally differs from ordinary soldering, in the circum- 
 stance that the uniting or intermediate metal is the same as those to be joined, and that in general no 
 fluxes are employed. 
 
 The method of burning together, although it only admits of limited application, is in many cases of 
 great importance, as when successfully performed the works assume the condition of greatest strength, 
 from all parts being alike. There is no dissimilarity between the several parts as when ordinary solders 
 are used, which are open to an objection, that the solders expand and contract by heat either more or 
 less than the metals to which they are attached. There is another objection of far greater moment : 
 the solders oxidize either more or less freely than the metals, and upon which circumstances hinge some 
 galvanic or electrical phenomena; and thence the soldered joints constitute galvanic circuits, which in 
 some cases cause the more oxidizable of the two metals to waste with the greater rapidity, especially 
 when heat, moisture, or acids are present. 
 
 In chemical works this is a most serious inconvenience, and therefore leaden vessels and chambers for 
 sulphuric acid must not be soldered with tin-solder, the tin being so much more freely dissolved than 
 the lead. Such works were formerly burned together by pouring red-hot lead on the joint, and fusing 
 the parts into one mass, by means of a red-hot soldering-iron. This is troublesome and tedious, and it 
 is now replaced by the autogenous soldering. 
 
 Pewter is sometimes burned together at the external angles of works, simply that no difference ol 
 color may exist; the one edge is allowed to stand a little above the other, a strip of the same pewter is 
 laid in the angle, and the whole are melted together, with a large copper-bit heated almost to redness 
 the superfluous metal is then filed off, leaving a well-defined angle without any visible joint. 
 
SOLDERING. 
 
 643 
 
 Brass is likewise burned together ; for instance, the rims of large mural circles for observatories, that 
 are live, six, or seven feet diameter, are sometimes cast in six or more segments, and attached by burn- 
 ing. The ends of the segments are tiled clean, two pieces are fixed vertically in a sand mould in their 
 relative positions, a shallow space is left around the joint, and the entire charge of a crucible, say thirty 
 or forty pounds of the melted brass a little hotter than usual, is then poured on the joint to heat it to 
 the melting point. The metal overflows the shallow chamber or hole, and runs into a pit prepared for 
 it in the sand ; but the last quantity of metal that remains, solidifies with the ends of the segments, and 
 forms a joint almost or quite as perfect as the general substance of the metal ; the process is repeated 
 for every joint of the circle. 
 
 The compensation balance of the chronometer and superior watches is an interesting example of 
 natural soldering. The balance is a small fly-wheel made of one piece of steel, covered with a hoop of 
 brass ; the rim consisting of the two metals, is divided at the two extremities of the one diametrical arm 
 of the balance, so that the increase of temperature which weakens the balance-spring contracts in a pro- 
 portionate degree the diameter of the balance, leaving the spring less resistance to overcome. This 
 occurs from the brass expanding much more by heat than steel, and it therefore curls the semicircular 
 arcs inwards, an action that will be immediately understood if we conceive the compound bar of brass 
 and steel to be straight, as the heat would render the brass side longer and convex, and in the balance 
 it renders it more curved. 
 
 In the compensation balance, the two metals are thus united : the disk of steel when turned and 
 pierced with a central hole, is fixed by a little screw-bolt and nut at the bottom of a small crucible with 
 a central elevation, smaller than the disk ; the brass is now melted and the whole allowed to cool. The 
 crucible is broken, the excess of brass is turned off in the lathe, the arms are made with the file as usual, 
 the rim is tapped to receive the compensation screws or weights, and lastly the hoop is divided in two 
 places, at opposite ends of its diametrical arm. 
 
 A little black-lead is generally introduced between the steel and the crucible ; and other but less 
 exact modes of combining the metals are also employed. 
 
 Cast-iron is likewise united by burning, as will be explained by the following example : to add a 
 flange to an iron pipe, a sand mould is made from a wood model of the required pipe, but the gusset or 
 chamfered band between the flange and tube is made rather fuller than usual, to afford a little extra 
 base for the flange. The mould is furnished with an ingate, entering exactly on the horizontal parting 
 of the mould, at the edge of the flange, and with a waste-head or runner proceeding upwards from 
 the top of the flange, and leading over the edge of the flask to a hollow or pit sunk in the sand oi 
 the floor. 
 
 The end of the pipe is filed quite clean at the place of junction, and a shallow nick is filed at the inner 
 edge to assist in keying on the flange ; lastly the pipe is plugged with sand and laid in the mould. After 
 the mould is closed, about six or eight times as much hot metal as the flange requires is poured through 
 the mould ; this heats the pipe to the temperature of the fluid iron, so that on cooling the flange is at- 
 tached sufficiently firm to bear the ordinary pressure of screw-bolts, steam, &c* 
 
 The method of burning is occasionally employed in most of the metals and alloys, in making small 
 additions to old castings, and also in repairing trifling holes and defects in new ones ; it is only success- 
 ful, however, when the pieces are filed quite clean, and abundance of fluid metal is employed, in order 
 to impart sufficient heat to make a natural soldering : a jjrocess which is also, although differently 
 accomplished, in plating copper with silver, as the two metals are raised to a heat just short of the 
 melting-point of the silver, and the metals then unite without solder by partial alloying. 
 
 To conclude the description of soldering processes, we have to refer to the airo-hydrogen\ blowpipe, 
 invented in France by the Count de Richemont. It is in a great measure converting the oxy-hydrogen 
 blowpipe, invented by Dr. Hare, to the service of the workshop, and it is done with great simplicity and 
 safety. An elastic tube supplies hydrogen from the generator, and a pipe supplies atmospheric air from 
 a small pair of double bellows worked by the foot of the operator, and compressed by a constant weight ; 
 the two pipes meet in an arch, and proceed through the third pipe to a small jet, from whence proceeds 
 the flame. All the connections are by elastic tubes, which allow perfect freedom of motion, so that the 
 portable blowpipe is carried to the work. 
 
 In soldering by the autogenous process, the works are first prepared and scraped clean as usual, the 
 hydrogen is ignited, and the size of the flame is proportioned by a stop-cock ; the ah' is then admitted 
 through the air-pipe until the flame assumes a fine-pointed character, with which the work is united 
 after the general method of blowpipe soldering, except that a strip of lead is used instead of solder, and 
 generally without any flux. 
 
 This mode is described as being suitable to most of the metals, but its best application appears to be 
 to plumber’s work. The weight of lead consumed in making the joints is a mere fraction of the weight 
 of ordinary solder, which is both more expensive and more oxidizable, from the tin it contains. The gas 
 soldering, as it is called, removes likewise the risk of accidents from the plumber’s fires, as the gas gen- 
 
 * Steam and water-tight joints, in cast-iron works not requiring the power of after-separation, are often made by means 
 of iron cement in the following proportions: 112 lbs. of cast-iron filings or borings, 1 lb. of sal-ammoniac, 1 lb. of sulphur, 
 and 4 lbs. of whitening. Small quantities of the materials are mixed together with a little water shortly before use. 
 
 For minute cracks the cement is laid on externally as a thin seam, or for larger spaces it is driven in with caulking-irons. 
 The edges of the metal and the cement shortly commence one common process of rusting, and at the end of a week or ten 
 days the joints will be found hard, dry, and permanent. 
 
 t The following is the broad difference between the airo-hydrogen and the oxy-hydrogen blowpipes. In the oxy-hydro- 
 gen blowpipe, the pure gases are mixed in the exact proportions of two volumes of hydrogen to one of oxygen, which 
 quantities when combined constitute water, and in this particular case there is the greatest condensation of volume, and 
 the greatest evolution of latent as well as of sensible heat. 
 
 The airo-hydrogen blowpipe is supplied wilh common air and with pure hydrogen; this instrument is also the most 
 effective when the oxygen and hydrogen are mixed in the proportions of 1 to 2; but the nitrogen, which constitutes four- 
 fifths of our atmosphere, is now in the way and detracts from the intensity of the effect. 
 
644 
 
 SPARK ARRESTER. 
 
 erator which is in itself harmless, may he allowed to remain on the ground whilst the workman ascends 
 to tne roof, or elsewhere, with the pipe. 
 
 Lead is interposed as solder in uniting zinc to zinc, and it is also used m soldei'ing the brass nozzles 
 and cocks to the vessels of lead, and those of copper coated with lead, used as generators. Another 
 very practical application of the gas flame is for keeping the copper soldering tool at one temperature, 
 which is done hy leading the mixed gases through a tube in the handle, so that the flame plays on the 
 back of the copper bit. This mode seems to be very well adapted to tin-plate and zinc works, espe 
 eially as the common street-gas may be used, thereby dispensing with the necessity for a gas generator 
 
 SPANDRIL. An irregular triangular space formed between the outer curve or extrados of an arch 
 and a line tangent at or near the crown, and the perpendicular line from the springing»of the arch. 
 
 SPARK ARRESTER — Cutting’s patent. Fig. 3339 is a vertical section of the machine. 
 
 Fig. 3341, a view of the diaphragm with its curved and inclined planes, separating the outer chamber 
 from the inner chambers, and exhibiting a view of the ventilators, or air-flues, in the lower or inclined 
 section. 
 
 Fig. 3342 is a horizontal view of the under side of Fig. 3341, showing a series of ventilators or air- 
 lines, and the curved plane. 
 
 Fig. 3340 is a perspective view of a section, showing the combination of the different parts. 
 
 Fig. 3343 is a horizontal view, taken at the line a a of Fig. 3344, showing the air-flue, and the en- 
 trance of the ventilating tubes. 
 
 Fig. 3344 is a vertical section of the chimney in combination with the ventilating tubes and air- 
 chambers. 
 
 The same letters in the several figures represent the same parts. 
 
 The nature of the first part of this invention consists in arranging upon the outside of the inclined 
 plane, at the base of the diaphragm, a series of air-flues, extending from the spark-chamber through 
 the diaphragm, the mouths of said flues being in the spark-cliamber, and their exits in the diaphragm, 
 so that the rotary current of steam, &c., through a series of curved flues in said diaphragm, will pass 
 over the exits of said air-flues, causing a current of air to be drawn from said spark-chamber through 
 said air-flues in the direction of the current of steam, &c., for the purpose of creating a partial vacuum 
 in said spark-chamber into which the sparks fall. And in order to effect the deposit of such light 
 particles as may possibly reach the top of the diaphragm, the nature of the second part of the in- 
 vention consists in arranging an air-chamber within the diaphragm at the top of the stack, which 
 chamber is ventilated or exhausted by means of tubes connecting that chamber with the air-flue at 
 the bottom of the chamber at the top of the chimney. 
 
 To enable others skilled in the art to make and use this invention, we will proceed to describe the 
 same with reference to the drawings. 
 
 3339. 3340. 
 
 At the top of the chimney A is placed an air-chamber B, over which is placed a deflecting cone C, in 
 the form of a funnel, with the outer edges turned down all around uniformly, to reverberate the steam, 
 gases, and particles, and throw them into a series of curved and inclined flues D, surrounding the air- 
 chamber B, by which a whirling or rotary motion is produced within the diaphragm 0. This dia- 
 phragm is provided with a series of apertures G-. The exhaust steam, in passing through th# 
 
SPEEDER 
 
 615 
 
 chimney A into the air-chamber B, has the effect of drawing a current of air between the curved plane 
 K, and the chimney A., through the air-flues F, out of the spark-chamber J. 
 
 The air-flues F are arranged on the outer side of the inclined plane E, at the base of the diaphragm, 
 and extend from the chamber J through the diaphragm O. The mouths of the flues F are in the spark- 
 chamber J, and their exits c in the diaphragm O, the current of air through them being in the direction, 
 of the current of steam, passing through the inclined flues D, as shown by the arrows, so as to allow 
 the air to pass out from, and prevent the sparks, &c., from passing into the spark-chamber through said 
 flues F. 
 
 At the bottom of the diaphragm 0, under the series of curved and inclined flues D, is a curved 
 plane K, and an inclined plane E. In the inclined plane E is placed the series of flues F above 
 described. The effect of the passage of thte circular current of steam, <fcc., within the diaphragm O, 
 and over the air-flues F, is to still further exhaust the spark-chamber J of its air, on the same prin- 
 ciple that the spark-chamber J is ventilated by the passage of steam, etc., over the air-flue P, (shown 
 by dotted lines in Fig. 3344,) at the bottom of the air-chamber B. 
 
 The circular current has the tendency by its centrifugal force to throw the particles off in a tan- 
 gent, against the inner walls of the diaphragm 0, and through the apertures G into the outer or 
 spark-chamber J. The deposit of the sparks, &c., in the spark-chamber J is greatly facilitated by 
 the action of the partial vacuum in the spark-chamber J, by which a draught is occasioned through the 
 apertures G of the diaphragm O, towards said spark-chamber J. 
 
 3341. 3344. 
 
 It will be seen that the spark-chamber J is exhausted of its air, in part, by every pulsation of ex- 
 haust steam, consequently between every pulsation there will be a draught towards the spark-chamber 
 J through the air-flue as well as through the aperture G of the diaphragm 0. This draught through the 
 air-flue towards the spark-chamber J will have the effect to create a draught upwards through the 
 chimney A, by which the draught of the furnace will be to a great extent regulated, and the heat cor- 
 respondingly increased. 
 
 Fig. 3344 represents the chimney A, with air-chamber B, in connection with 'he pipes H, which 
 pass to another air-chamber I, at the top of the stack. The passage of the steam through the chim- 
 ney A tends to draw a current of air through the pipes H, in the same manner in which the ventila- 
 tion of the spark-chamber J is effected, the result of which is to exhaust the air-chamber I of a por- 
 tion of its air. This air-chamber I is provided with apertures, the object of which is to arrest such 
 light particles as may possibly reach the top of the stack, and cause them to pass around again with 
 the view of their being deposited. L is the general outlet of the steam and such gases as may be 
 evolved. 
 
 SPECIFIC GRAVITY. See Gravity. 
 
 SPEEDER. After cotton in the course of preparation for yarn has passed through the drawing-frame, 
 the next operation is the making of roving ; this is effected in most American mills by the speeder. 
 Of speeders there is some variety ; as the Taunton speeder, the Eclipse speeder, the Plate speeder, and 
 the Double speeder. The rovings produced from the first three are alike, having no twist and built on 
 bobbins or spools with conical ends. In the first the roving passes through a revolving tube, in the 
 second between two opposing surfaces of a travelling endless belt ; in the third, between two plate sur- 
 faces revolving in opposite directions. The double speeder is somewhat similar to the English bobbin 
 ana fly frame. The double speeder is made in two different forms, the first of which receives the arms 
 
04G 
 
 SPIKE MACHINE. 
 
 direct from the drawing frame, and has only one row of spindles on one side of the frame ; these are 
 usually called speeders: the other receives the bobbins from the speeders and still further reduces the 
 rovings ; these are called stretchers, and have rows of spindles on each side like the throstle. The 
 roving from these machines, unlike the first varieties, has a little twist : the chief objection to them 
 lies in the power required to drive them, and on this account chiefly, they have been superseded by the 
 bobbin and fly frame in the finer mills ; two machines being commonly used, corresponding to the 
 speeder and stretcher, a coarse and fine frame. In their general action they may be said to unite the 
 drawing and spinning frame, performing both processes, and being the connecting link between the two. 
 
 SPIKE MACHINE. Burden’s Patent. “ In my improved machine, the feeding in of the rod, the 
 rutting it off, and the pointing the spike, are effected in the way previously used by me for performing 
 
SPIKE MACHINE. 
 
 647 
 
 3346. 
 
 the same offices in my ordinary spike machines, 
 or adopted by others ; and my improvement for 
 forming the spikes with hook or brad heads, may 
 be applied to spike machines of various construc- 
 tions. 
 
 Before the introduction of my improvement, 
 the heads of hook or brad-headed spikes were, 
 so far as I am informed, always made by hand, 
 and they were necessarily imperfect, being de- 
 ficient in that uniformity in shape and strength 
 which are important requisites. My improve- 
 ment in manufacturing them consists principally 
 in the employment of what I denominate a bend- 
 ing lever, or some analogous device, by means of 
 which the portion of the rod which is to consti- 
 tute the head is bent down so as to form an angle 
 with the shank, and in then forcing up a heading 
 die, properly formed, so as to upset the bent 
 portion, and to cause it to assume the desired 
 shape. 
 
 In each of these figures, where like parts are 
 shown, they are designated by the same letters 
 of reference. A A is the bed-plate upon which 
 most of the operating parts of the machine are 
 sustained. B B are the dies which grip and hold 
 the spike-rod during the time the bending and 
 heading are effected. C is a lever by which the 
 die B is closed, the die B being stationary. This 
 lever is acted on by the segmental cam D on 
 the driving-shaft E of the machine ; the frame 
 F F, which holds the die H, works on a joint- 
 rod c c, and is lifted by the strap cl d, attached 
 by the joint-pin e to the lever C. The spike-rod 
 
 amS 
 
G48 
 
 SPIKE MACHINE. 
 
 fia to be fed into the dies in the usual way, and as soon as the dies are closed upon the piece to be 
 headed, the bending lever G has its outer end h raised by the cam II on the shaft E, which causes its 
 end g to descend upon the projecting end of the spike-rod, and to bend it down in the manner shown. 
 I is the heading-slide which carries the heading-die J, and as soon as the cam H escapes from the outer 
 end of the bending lever h, and that end descends, the cam K comes in contact with the end L of the 
 heading-slide, which it forces. 
 
 In the accompanying figures a represents the frame-work of the machine, in which are hung tne 
 shafts b b b of three rolls ccc, arranged at equal distances around a common axis. Each shaft has two 
 journals running in boxes dd, the lower one so mounted in the frame by means of set-screws e the axis 
 of the rollers can be adjusted in a radial direction from or towards the central line around which they 
 are arranged. The rolls are frustums of cones from the lines 1 to 2, and 2 to 3, which is the extremity 
 of the rolls ; they are in the form of the frustum of a flatter or more obtuse cone, so that in the plane 
 of the radii of the common centre, the latter part will be parallel with the common axis around which 
 the three rolls are arranged. 
 
SPIKE MACHINE. 
 
 641 } 
 
 3353. 
 
 335G. 
 
 3249. 
 
650 
 
 SPIKE MACHINE. 
 
 There is a cog-wheel/ on the shaft of each of the rolls, the three being of equal diameter, and these, 
 three are caused to rotate in the same direction by means of two intermediate cog-wheels g g. The 
 driving power should be applied to the shaft h of one of the rolls in any desired manner, although it 
 may be applied to the shafts of one of the intermediate wheels. The dotted lines ij in sections, 
 represent the inclination of the axis of the rolls, and the intermediate wheels form the axis round 
 which they are arranged, and the dotted lines k k k represent vertical planes radiating from this 
 common axis, and the dotted lines III the lines of the axis of the three rolls which are slightly inclined 
 thereto 
 
 When the rolls are set in motion a loop or ball of iron m, in a highly heated state, is dropped in be- 
 tween them, at their upper end, the frame-work being left open above for that purpose, and the slight 
 inclination of the axis of the three rolls from the vertical plane, as indicated by the dotted lines b bb, 
 causes the rolls gradually to carry down between them the ball of iron towards their lower end, where 
 they are nearer together by reason of the inclination of their axis from the vertical line being greater 
 than the lines of the cones. 
 
 By this means not only is the mass of iron gradually drawn down in the direction of the common 
 axis, around which the rolls are arranged, but by the action of the rotating surface of the rolls, in a 
 line nearly at right angles to this common centre, the iron is rotated on its axis and squeezed in a spiral 
 direction, and the mass gradually elongated and carried out at the bottom in a round bar n, of a di- 
 ameter equal to the space between the lower end of the three rolls, where the cones are so flat as to 
 reduce the bar to a cylindrical form. For the purpose of preventing the rolls from being overheated 
 
STATIONARY STEAM ENGINE. 
 
 651 
 
 by contact with the highly heated mass of iron under treatment, the rolls may be made hollow 
 as indicated by the dotted lines, with a central water-tube o, extending down to near the bottom, 
 through which water is introduced, and which flows out around the tube, and is discharged at 
 the top. 
 
 Fig. 3345 elevation of right side of machine, showing the fly-wheel, pulleys, bands, and fixtures, to 
 apply the moving power. 
 
 Fig. 3345a section of same through cd. 
 
 Fig. 3346 elevation of left side of machine when closed in the act of finishing a spike. 
 
 Fig. 3346a section of same through a b. 
 
 Fig. 3347 front elevation, with pointing-levers closed. 
 
 Fig. 3348 rear elevation, with pointing-levers closed. 
 
 Fig. 3349 longitudinal section and elevation of machine, prepared for making hook-head spikes, th* 
 machine open, and immediately after forwarding the nail-road, and ready for the downward motion oi 
 the upper lever and hooker. 
 
 Fig. 3350 section after the downward motion of upper lever and hooker. 
 
 Fig. 3351 section after the downward motion of upper lever and hooker, with the header home and 
 the spike headed and pointed. 
 
 Fig. 3352 plan of heading-box and heading-lever B, heading-bolt FT. 
 
 SPINNING FRAME. See Mule and Throstle. 
 
 SPINNING-FRAME BANDING, MACHINE FOR MAKING. Applicable to the making of small 
 cord for any purpose. 
 
 Description. — A, Fig. 3361, is the combination of fixed loose pulleys receiving the driving-band. B 
 is a cone, from which a band leads to a round cone directly in the rear of B on the shaft b ; thence In 
 another band to the pulley c motion is communica- 
 ted to shaft c, which takes up the banding as it is 
 laid, which from thence passes to a bobbin, and is 
 wound by the friction of a drum on which the bob- 
 bin lies, which is driven by a band from the pulley 
 f, but which are not shown in the drawing. E is 
 the machine which lays the banding. A revolving 
 motion is given by the band-geer C around the fixed 
 spindle D, while the upper is steadied in a socket 
 at d. and the whole is supported by the point l 
 bearing on the top of D. The twist to be made 
 into banding is wound on two bobbins p placed 
 within the flyers /(, held between two disks, which 
 disks are kept together firmly by two rods, not 
 shown in the figure. The twist, as it leaves the 
 bobbins, passes round the rim of the flyer, or 
 through a staple in the conical weight i, thence 
 through a hole in the end of the bar f, thence 
 through the centre of the flyer twice or thrice 
 round the geered rolls k, thence through the centre 
 of the spindle of the machine E, when the two 
 strands are twisted together or laid. The shaft E 
 takes up and dedivers the banding. It is evident 
 that in laying the banding, if the bobbins were 
 stationary, a portion of the twist would be taken 
 out ; to remedy this by meaus of the geer m fixed 
 on the spindle D and an intermediate n, motion is 
 given to thenjgeer o to which the flyer is fastened ; 
 by this means, as much or more twist is put into 
 the strands as would be lost in the laying. The 
 bobbins of twist p are held on spindles, which spin- 
 dles fit into a socket in the bottom of the flyer, and the upper end passing through the bar_/" is held by 
 a small screw. To take out the spindle, the bar f can be revolved. 
 
 STATIONARY STEAM ENGINE. Under the head of “Engine” will be found the usual varieties 
 of Stationary Engines. By far the largest class in this country are horizontal cylinders, with every va- 
 riety of valve and cut off. Of late years it has been found economical to avoid wire drawing, to open 
 and close the steam ports as suddenly as possible, and to attach the governor directly to the steam-valve. 
 Of this class of engines Mr. Geo. H. Corliss, of Providence, has been the most successful builder and 
 inventor. Plate VII represents one of his engines : in this case a vertical engine, but the improvements 
 are equally adapted to horizontal engines. 
 
 Stationary Steam Engine, Corliss Patent. The chief peculiarities lie in the method of working the 
 valves, and in controlling the valve motion by the governor, so as to regulate the motion of the engine 
 with perfection, and use the steam to the best advantage under all conditions. 
 
 The valves employed are rotary sliding valves. Their motion is similar to that of the common plug- 
 cock or faucet, but the form adopted is such that they fill a portion only of the cylindrical cavities in 
 which they are mounted. The connection of each valve to its spindle or stem is such that it is free to 
 adapt itself to all conditions. It works freely and yet remains tight, precisely like an ordinary slide 
 valve. There are two steam valves cd , and two exhaust valves ef all worked independently, yet by 
 simple mechanism. The exhaust valves are held open during the whole stroke of the piston, but the 
 steam valves are opened at the proper time and allowed to shut automatically at some point in the early 
 
652 
 
 STATIONARY STEAM ENGINE. 
 
 portion of the stroke. The precise point at which this shutting of the steam valve occurs, and conse- 
 quently the volume of steam admitted into the cylinder in any g ven stroke, depends on the position of 
 the governor balls 1, and the speed of the engine is regulated by the variations in the quantity of steam 
 thus admitted. The principal improvements in this engine are therefore twofold. 
 
 First: There is a peculiar device for moving each steam valve and each exhaust valve, with a dis- 
 tinct and independent motion, by means of a crank- wrist. A series of crank wrists, a 1 a 3 a 3 u‘, are at- 
 tached to a common disc or plate, a, which latter is secured to a rock shaft connected with the main ec- 
 centric. Each wrist operates through a distinct lever upon its proper valve ; and all of the wrists are 
 so arranged on the common wrist-plate, with reference to their levers, that they act like cranks, each of 
 which vibrates near its dead point or point of slowest throw, and therefore imparts but little movement 
 to the valve it actuates, while that valve is closed, and moves with its fastest throw, and therefore im- 
 parts the greatest movement to its valve, during the opening and closing motions. This is a substitute 
 for the common slide valve arrangement. As commonly constructed, a steam valve and an exhaust valve 
 are rigidly connected together, so that when one is moved the other is forced to move equally with it. 
 
 The whole amount of force consumed in unnecessarily moving a valve while closed, is expended to no 
 good purpose, and tends to increase the wear of the engine. The new device therefore, secures two ad- 
 vantages : first, it saves much of the power which was injuriously expended in moving the closed valve ; 
 second , it prevents wire-drawing or waste of the expansive force of the steam, because the valves are 
 moved with increased speed while opening and closing their ports. 
 
 The second improvement in this engine consists in a method of automatic regulation of the steam in 
 its passage into the cylinder, so that, by means of the steam valves only, the entire expansive force of 
 the steam is saved and applied. This is effected by combining the governor — all its sensibility being 
 completely preserved — through the agency of stops or cams, with the catches that liberate the steam 
 valves for the purpose of cutting olf the flow of steam into the cylinder. 
 
 The Corliss engine then, is a steam engine with sliding or circular valves, and with a new valve-gear 
 adapted to perfect automatic regulation and to the saving of fuel. The regulation in this engine is purely 
 automatic, and practically perfect, as it acts without impairing the effect of the steam. The common 
 method of regulation is by the employment of a throttle valve, a kind of damper in the steam pipe, de- 
 scribed on page . This is connected to the governor, so that as the speed of the engine is increased 
 the aperture through which the steam passes is diminished ; by thus retarding its flow, the pressure of 
 the steam in the cylinder is diminished, and the velocity of the engine is consequently checked. The 
 action is a continual choking of the engine, which is increased and diminished according to circum- 
 stances, but is always a tax on the power. The loss by the use of the throttle-valve is universally ac- 
 knowledged to be very serious. Maudsley, in Great Britain, and several others, succeeded in regulating 
 by varying the cut-off by the hand of an attendant, but the adjustments could not be successfully effect- 
 ed by the governor prior to this invention, as the power required to change the parts exhausted the sen- 
 sibility of the governor and made the motion very irregular. Even the slight resistance experienced in 
 turning a throttle-valve — as it is necessarily effected through the intervention of a steam-tight stuffing 
 box- — is sufficient to affect the action of the governor, and make the throttle regulation not only waste- 
 ful, but imperfect. In the method here represented, there is practically no resistance to the rise and fall 
 of the governor balls, and the engine is found to work with apparent uniformity, even in driving such 
 machinery as large rolling mills, where the resistance varies suddenly from 60 to 360 horse power. 
 
 In the engraving, the letters c and d as before observed, indicate the steam valves, or rather indicate 
 levers, keyed on the stems of such, and by which they are worked. Near the extremity of each rody 
 and k , is provided a suitable hook or catch, which at each rocking movement of the plate, a, seizes the 
 respective lever c or d, and opens the valve, but by a movement which necessarily presses the polished 
 side of j or k against the end of one of the light and loosely mounted slides n n. This contact, as the 
 circular motion of the wrist pin a' or a? continues, aided by the curvilinear motion of the extremity of 
 the lever, compels the hook to slip off and release its valve, which is then immediately closed by a 
 weight suspended to the rod r or s. The slight rods or slides n n, are free to slip endwise until their op- 
 posite extremities press against the side of the pieces o o, mounted for the purpose on the rod m of the 
 governor. The sides of o o are inclined slightly, and as they are elevated by the rise of the governor 
 balls, they urge n n forward, and cause the hooks to detach and the steam valves to shut at an earlier 
 point in the stroke. When, on the other hand, the engine inclines to run too slow, and the balls sink, 
 the slides n n, yield to the slight pressure of j and k, and slip back until they are in contact with o, and 
 thus more steam is admitted into the cylinder, the steam valves not being detached until a later period 
 in the stroke. In case either the resistance to the motion of the engine becomes very great, or the 
 pressure of the steam becomes very slight, the slides n n retreat so far that they fail to detach the hooks 
 and the steam valves consequently remain open during the whole stroke, like the exhaust valves. 
 
 It will be observed that in this engine the governor nowhere performs any labor, and, on the contrary, 
 only indicates the change required to the levers which move the valves. This does not task its powers : 
 it puts forth only the force necessary to move the small stops nn. This movement is attended with the 
 least possible friction, and the stop presents absolutely no resistance to the governor, except at the very 
 instant when it is in actual contact withy or k. 
 
 In puppet-valve engines, the valves must be started from their seats or places of rest at the moment of 
 opening their ports. In this engine, as we have seen, the sliding or circular valves have a rapid mo- 
 tion at that point, analogous to, but faster than, that in the common slide valve arrangement. This al- 
 lows the ports to be uncovered and covered very rapidly, without involving any accompanying sudden 
 motions and concussions. It allows the valves to be opened very widely with great rapidity, a point of 
 considerable importance in the motion of the exhaust valves, as it is always desirable to discharge the 
 steam as freely and rapidly as possible when its work is performed. But its greatest merit lies in the 
 dvet that it prevents a wire-drawing of steam at the closing of the steam valves, by means of the suck 
 
STAVE-DRESSING MACHINE. 
 
 653 
 
 cienness of the motion ; a result which cannot he obtained in an engine having puppet- valves, because 
 the descent of the valves by gravity, must, in such engines, be very moderate at the termination of the 
 motion, to prevent their slamming on their seats. 
 
 The alternations in the action of the steam, as ordinarily effected, are constantly in progress. The 
 opening for the admission of the steam enlarges gradually, and is no sooner fully and freely open than 
 it commences to close : the same is true cf the opening for the exhaust. In order to so effect the op- 
 erations of admitting and discharging the steam that the mean of each shall be at the proper time, it is ne- 
 cessary to commence a certain time in advance. Thus the steam begins to enter the cylinder to produce 
 a movement of the piston in one direction before the previous stroke has been fully completed, and con- 
 sequently acts for a brief period in the wrong direction, or as a retarding force ; and subsequently begins 
 to escape, and to lose its effect before the piston has completed its proper movement. These imperfec- 
 tions in the action of the steam are unavoidable in the common varieties of the steam engine, whether 
 using slide valves or puppet valves, but are completely avoided in this style of engine ; the steam being 
 admitted and discharged very freely, and at the moment the piston is at the ends of the stroke. The 
 construction allows of the adjusting of the valve motion so as to receive and discharge a little in ad- 
 vance or a little behind this period if preferred, and in fact, these engines are frequently adjusted in va- 
 rious conditions in this respect ; but the necessity for commencing either operation in advance, or giving 
 “lead” to the valves, is entirely removed by the rapidity with which it is effected. 
 
 Perfection of economy in the use of steam is to admit it freely at a high pressure at the moment the 
 piston commences its stroke, and allow it to follow at full pressure through such a fraction of the stroke 
 that the subsequent expansion shall, during the remainder of the stroke, reduce it to the lowest pressure 
 at which it can be useful. A certain amount of pressure, varying from one to three or four, pounds 
 is always required to overcome the friction of the engine. Whenever steam is discharged from a cylin- 
 der at a higher effective pressure than this, it proves that there is still power remaining in it which 
 might have been utilized by a better arrangement and proportion of the engine. It might seem reason- 
 able to suppose that the gain of effect due to expansion, explained on page , may be increased in- 
 definitely by increasing the initial or boiler pressure, and cutting off at a proportionally early period in 
 the stroke ; but there are other considerations, due to the strains on the parts, the friction of the surfaces, 
 and the leakage of steam, which limit it. In the Corliss engine, the average expansion allowed is that 
 found most economical in practice. 
 
 It should be premised that it requires a higher temperature , but only a very little greater amount, of heat, 
 to evaporate a given quantity of water at a high pressure than at a low. Recent elaborate scientific 
 experiments, as also the results of general experience, assure us that there is a little, and but a little 
 difference in the amount of fuel consumed, in evaporating a cubic foot of water at 100 pounds pressure 
 or at 1 pound pressure, while the power derivable is much greater from the steam of highest pressure, 
 used expansively as above described. The actual cost for fuel to obtain any given power, is a subject 
 which has not received the attention it deserves. The following condensed tabular statement indicates 
 the actual performances of these engines. The data are from large mills in ordinary and constant use, 
 and in this respect differ very widely from experiments conducted for short periods and with miniature 
 apparatus, — good common engines had been previously employed in each. 
 
 The quantities marked with an asterisk (*) indicate the amount used for heating and dressing in addition to 
 that required for power. 
 
 Establishment. 
 
 Horse power 
 by Indicator. 
 
 lbs. Coni consumed per 
 day with Corliss Engine. 
 
 lbs. Coal per Morse 
 per Hour. 
 
 * Ounces Coal per 
 day per Spindle. 
 
 lbs. Coal consumed 
 with former Engines. 
 
 Atlantic M l, Prov- 
 idence R. I. 
 
 1 
 
 o 
 
 Cl 
 
 6,000 
 
 T88 
 
 3-942 
 
 — 
 
 Bartlett M’lsNew- 
 buryport, Mass. 
 
 200 
 
 6,000* 
 
 . 2-5* 
 
 5-690* 
 
 9,250* 
 
 James Mills, do. 
 
 190 
 
 5,690* 
 
 2 5* 
 
 5-27* 
 
 10,483* 
 
 Globe Mills, do. 
 
 294 
 
 8,800* 
 
 2-49* 
 
 — 
 
 11,000* 
 
 Crocker & Bro’s, 
 (Rolling Mill,) 
 Taunton, Mass. 
 
 60 to 860 
 
 4,000 
 
 — 
 
 
 10,000 
 
 STAVE-DRESSING MACHINE. Fig. 3362 gives only a representation of this machine in the 
 manner of looking down upon the face of the frame, therefore the geering underneath cannot be seen ; 
 but from this vertical view a good mechanic will be able to trace the relation of the different parts, and 
 perceive the beauties of the whole machine and its adaptations to the purpose, so much to be desired 
 and so essential to the great and rising trade of American cooperage. 
 
 A A A is the frame ; K is the iron bed-plate represented by the dark shading. B represents the large 
 knife or cutting-roller, somewhat hid by the belt which drives it from the power-roller D. C C are 
 friction-rollers, edged, as it were, to run upon a rail to keep the large knife-roller steady, and underneath 
 is another for the same purpose, all three set equidistant, like at the points of a triangle. E H are rollers 
 connected with another belt to drive the small knife-roller I. G is a driving-belt on an idle roller near 
 the motion or drive pulley F. N N are pulleys which are driven by a cross rope-belt to drive a hori- 
 zontal shaft, on which is the notched wheel which moves the two vertical shafts or feeding-rollers (two 
 biting wheels) a a, and which are now represented as feeding a stave into the knife-rollers. E is a spiral 
 spring which makes the feeders accommodate themselves to the bendings of the staves, b is a rest on a 
 straight line which keeps the stave up to the other two smooth rollers with springs cd, which act as 
 subordinate to the biting feeders. C is another rest and roller to keep firm the small cutting-roller T, 
 between which and the large knife-roller B the stave passes and comes out shaved through the centre 
 
G54 
 
 STAVE- JOINTING MACHINE. 
 
 of B, tlie large cutting-roller, -which is open. L is the lever or handle to set the feed-geer in motion, bj 
 lifting the wheel which drives the feed-shafts. 
 
 The nature of this invention and improvement consists in combining and arranging two revolving rings 
 or wheels having cutters on their opposing surfaces uext each other, for shaving the stave transversely 
 on both sides at once, producing a stave the cross-section of which is the segment of a circle, the diam- 
 eter of which is to be greater than the diameters of the wheels, and the curve of the stave being variable 
 at pleasure for all kinds of casks. The position of the whole geering can be changed to suit the angle 
 of the stave’s curvature, as the stave moves on the cutters it being the hvpothenuse of a right-angled 
 triangle formed by the parallel lines on which the cutters are placed. The whole machine is constructed 
 on the principle of considering a circle (for the curvature) to be a regular polygon of an indefinite num- 
 ber of sides, the sum of the sides being the perimeter of the circle. 
 
 3302. 
 
 A patent was granted for this machine to Judson <fc Pardee, New Haven, Conn. It cannot but be >1 
 great benefit to our country, as it destroys at once the rough, slavish work of cooperage, and lets the 
 cooper occupy his hands with the most light and easy parts of his trade. 
 
 STAVE-JOINTING- MACHINE. Fig. 3363 is an engraving of a stave jointer, the invention of Mr. 
 H. Law, of Wilmington, North Carolina, who has taken measures to secure a patent for the same. Its 
 utility, nature, and mode of operation will be fully understood by the following description : 
 
 AAA, frame. B, lever, which moves the frame L L, together with the saw and roller D, which are 
 all attached to frame L L. C, lever, by means of which lever B is moved. D D, concave rollers under 
 which the stave passes. E E E E, standards to support D D. F F, circular saws, standing in a raking 
 position, verging in opposite directions, so as to give the proper bevel to the edges of the stave. GG 
 G G, raised pieces over which the stave passes, which raised pieces together with the concave rollers 
 D D form throats or slots just the thickness of the stave, and through which the stave is made to pass 
 H, a guide-piece to conduct the stave to the second saw. I, a light spring to press the stave against the 
 guide-piece H. J, the end of the feed-chain which connects with the dresser. K K, dogs or hooks, at- 
 tached to the endless chain and traversing in the curved slot S S S to carry forward the stave — the chain 
 
 is underneath, and does not appear in the engraving except at J. L L, movable frame that supports 
 the saw, and that is attached to and acted upon by lever B to adjust the saw to the width of the stave. 
 M, journal-box. P P, pulleys to drive the circular saw. 0, pawls, or hold-fasts, to lever C. N N, weight 
 
 ani rope that move lever B. Q Q, index beds. R, curved piece attached to lever B dotted 
 
 curved line ranging with the saw, and governing the feed of stave on that side. 
 
 Operation .— The stave is deposited by the machine on the floor of the jointer, and is placed by hand 
 With the back of the stave up, with one edge on the dotted lines, being the proper position for that edge 
 
STEAM. 
 
 655 
 
 ro be jointed by the first saw, and with a single glance of the eye on the index lines on the near side the 
 tender can see what width the stave will bear; if it is described, for instance, by the first line, the lever 
 0 is immediately placed on the corresponding first line, and held fast by pulley O, or if the stave is of 
 some other width it is readily seen, and the lever C placed in the proper position ; but it is not conve- 
 nient that the saw should take that position immediately, therefore lever B is still held fast in its former 
 position by ratchets underneath and attached to circular piece It, which circular piece is attached to and 
 traverses with lever B. There is a ketch attached to the frame of the machine, which is pressed into 
 r-he ratchets and holds fast lever B. This hold-fast is tripped by one of the dogs passing through a 
 throat under the floor at the proper time, when the weight N immediately shifts lever B to lever C, and 
 places the saw in its proper position. The dog that carries the stave forward traverses in a curved line 
 corresponding to the bilge or taper of the stave, giving to the stave its taper, and both saws standing in 
 a raking position corresponding to the bevel of the stave, gives to the stave its proper bevel, the stave 
 passing between the raised pieces GGGG and the concave roller 1) D, which together form a slot just 
 the thickness of a stave, must of necessity bring every crook or twist fair to the saw, jointing to corre- 
 spond with the crooks and twists, and making a more perfectly shaped stave than can possibly be done 
 bv the hand. The staves are pressed by springs (which do not appear in the engraving) up against the 
 rollers D D, and as the rollers are more concave than the stave is convex, one edge of a narrow stave 
 is forced into this concavity and presents an edge less bevelling to the saw than a wide stave does, 
 so that without any alteration of machinery the bevel is made to correspond to the width of the stave ; 
 to accomplish this with the second saw the concave roller, together with the near standard E and raised 
 piece Gr, is attached to the frame and shifts with the saw. 
 
 STEAM. The elastic fluid into which water is converted by the continued application of heat. 
 
 All liquids whatever, when exposed to a sufficiently high temperature, are converted into vapor. 
 The mechanical properties of vapor are similar to those of gases in general. The property which is 
 most important to be considered, in the case of steam, is the elastic pressure. When a vapor or gas is 
 contained in a close vessel, the inner surface of the vessel will sustain a pressure arising from the elas- 
 ticity of the fluid. This pressure is produced by the mutual repulsion of the particles, which gives them 
 a tendency to fly asunder, and causes the mass of the fluid to exert a force tending to burst any vessel 
 within which it is confined. This pressure is uniformly diffused over every part of the surface of the ves- 
 sel in which such a fluid is contained : it is to this quality that all the mechanical power of steam is due. 
 
 To render the chief properties of steam intelligible, it will only be necessary to explain the phenomena 
 which attend the conversion of water into vapor by the continued application of heat, under the various 
 circumstances of external pressure which present themselves in the processes of nature and art. 
 
 Let A B, Fig. 3364, be a tube or cylinder, the magnitude of whose base is a square inch, and 
 let a piston move steam-tight in it ; let it be imagined that under this piston, in the bottom of 
 the cylinder, there is an inch depth of water, which will therefore be in quantity a cubic 
 inch ; let the piston be counterbalanced by a weight W acting over a pulley, which shall 
 be sufficient to counterpoise the weight of the piston and its friction in the cylinder ; and 
 let the weight W be so arranged that from time to time its amount may be diminished to 
 any required extent. Under the circumstances here supposed, the piston being in contact 
 with the water, and all air being excluded from beneath it, it will be pressed down by 
 the weight of the atmosphere, which we shall assume to be 14f lbs. Let it be also sup- 
 posed that a thermometer is placed in the water under the piston, and that the tube A B 
 is transparent, so that the indications of the thermometer may be observed. The temper- 
 ature of the water under the piston being reduced to that of melting ice, which is 32° of 
 the common thermometer, let the flame of a lamp be applied under the tube, and let the 
 time of its application be noted. If the thermometer be now observed, it will be seen slowly and grad- 
 ually to indicate an increasing temperature of the water, the piston maintaining its position in contact 
 with the water unchanged. This augmentation of the temperature will continue until the thermometer 
 indicates the temperature of 212°. Let the time be then noted. It will be found that after that epoch, 
 the water will cease to increase in temperature, notwithstanding the continued application of the lamp, 
 the thermometer not rising above 212°. But another effect will begin to be manifested; the piston 
 will be observed gradually to rise, leaving a space apparently vacant between it and the water. The 
 depth of the water will, however, be at the same time gradually diminished, and the diminution of its 
 depth will be found to bear constantly the same proportion to the ascent of the piston. This propor- 
 tion will render the circumstances here supposed to be that of 1 100 to 1. If the application of the 
 lamp be continued, and the tube have sufficient length, the water will, after the lapse of a certain time, 
 altogether disappear from the bottom of the tube ; and when that occurs, the piston will have risen to 
 the height of 1700 inches, being 1700 times the original depth of the water. 
 
 The tube will now, to all appearance, be empty ; but if the apparatus were weighed, it would be 
 found to have the same weight as at the commencement of the experiment. The water, therefore, must 
 Btill be contained in the tube, though it has assumed an invisible form. To demonstrate its presence, let 
 the lamp be removed ; immediately the piston will begin to descend, and the inner surface of the tube 
 will be covered with a dew, which speedily increasing, will fall to the bottom in drops of water. The pis- 
 ton meanwhile will continue to move downwards, sweeping before it the water from the sides of the tube ; 
 and at length will recover its first position, having under it, as at the beginning, a cubic inch of water. 
 
 In the above process, the elevation of the piston is produced by tbe elastic force of the steam, into 
 which the water was gradually converted by the lamp. The space between the piston and the water 
 during its ascent, though apparently empty, was filled with steam; which, like air and most other 
 gases, is a colorless and invisible fluid. The proportion of the elevation of the piston to the diminution 
 of depth of the water being 1700 to 1, proves that the water in passing into steam increases its volume 
 in that proportion. When the water altogether disappeared, the height of the piston from the bottom 
 of the tube was 1700 inches; and as the tube under the piston was then filled with the steam into 
 
 3364. 
 
656 
 
 STEAM. 
 
 which the water had been converted, it is apparent that the cubic inch of water, in this case, was con- 
 verted into 1700 inches of steam. 
 
 The pressure of the atmosphere above the piston was, in this case, overcome by the elastic force o.f 
 the steam, and the piston, bearing that pressure upon it, was raised to a height of 1700 inches. In the 
 evaporation, therefore, of this cubic inch of water, a mechanical force has been evolved equivalent tc 
 14J lbs. raised to the height of 1700 inches. 
 
 From the moment at which the water began to be converted into steam the thermometer, having 
 then attained 212°, ceased to rise. Nevertheless, the application of the lamp was continued, and there- 
 fore the same quantity of heat per minute was still supplied to the water. Since the water did not 
 increase in temperature, it may be asked what became of this continued supply of heat received from 
 the lamp ? It may be said that it was imparted to the steam into which the water was converted ; but 
 if the thermometer were raised out of the water, and held in the steam between the water and the pis- 
 ton, it would still indicate the same temperature of 212°. We thus arrive at the extraordinary and 
 unexpected fact, that notwithstanding a large supply of heat imparted to water during its evaporation, 
 that heat is sensible neither in the water itself nor in the vapor into which the water is converted. 
 
 The quantity of heat which is thus absorbed in converting water into steam is easily determined, the 
 interval of time being noted which elapsed between the first application of the lamp and the moment 
 at which the thermometer ceased to rise. Let us suppose that interval to be an hour ; the interval be- 
 ing also noted between the moment the thermometer ceases to rise and the process of evaporation 
 begins, and the moment at which the last particle of water disappears from the bottom of the tube and 
 the evaporation is completed, it will be found that this interval is 54 hours ; and in general, whatever 
 may be the length of time necessary to raise the temperature of the water from 32° to 212°, 5| times 
 that interval will be necessary for the same source of heat to evaporate the same quantity of water. 
 It follows, therefore, that to evaporate water under a pressure of 14f pounds per square inch requires 
 5J times as much heat as is necessary and sufficient to raise the same water from 32° to 212°. 
 
 Since the difference between 212° and 32° is 180°, and since 5-J- times 180° is 990°, it follows that 
 to convert the water into steam after it has attained the temperature of 212°, as much heat must be 
 supplied to it as would be sufficient, if it were not evaporated, to raise it 990° higher. The heat thus 
 absorbed in evaporation, and not sensible to the thermometer, is said to be latent in the steam ; and 
 the phenomena which have been just described form the foundation of the whole theory of latent heat. 
 That this large quantity of heat is actually contained in the steam, though not sensible to the thermo- 
 meter, admits of easy demonstration, by showing that it may be reproduced by converting the steam 
 into water. If a cubic inch of water, in the form of steam at the temperature of 212°, be introduced 
 into the same vessel with 5J cubic inches of water at the temperature of 32°, the steam will be imme- 
 diately converted info water; the temperature of the inches of ice-cold water will be raised to 212°, 
 and there will be found in the vessel 6^- cubic inches of water at 212°. Thus, while the steam, in re- 
 assuming the liquid form, has lost none of its temperature, it has nevertheless given up as much heat 
 as has raised 5^- cubic inches of water from 32° to 212°. It is therefore demonstrated that this quan- 
 tity of heat was actually in the steam ; and that it was its presence there in the latent state, by some 
 agency not yet explained, that conferred upon the water in the vaporous form the property of elasticity. 
 
 We have here supposed that the pressure under which the water in the tube was evaporated was 
 the mean pressure of the atmosphere, or 14 j lbs. per square inch. Let us now suppose that the piston 
 resting on the water is loaded with a force of 14f lbs., besides the pressure of the atmosphere, which 
 may be done by taking 14 J lbs. from the counterpoise W. If the same process be followed as before, 
 it will now be found that the thermometer will not cease to rise when it has attained 212° ; nor will 
 the piston then begin to ascend. The thermometer will, on the other hand, continue to rise until it has 
 attained 250°. It will then, as in the former case, cease to rise ; the piston will ascend, and the water 
 will begin to be converted into steam ; the proportion, however, between the ascent of the piston and 
 the diminished depth of the water, or, in other words, between the volume of steam produced and the 
 volume of water producing it, instead of being 1700 to 1, will now be about 930 to 1, being little more 
 than half the former proportion. The force against which the elasticity of the steam, in the present 
 case, acts, is 294 lbs. ; and this force is raised about 930 inches by the evaporation of a cubic inch of 
 water. In the former case, a force of 14J lbs., being half the present force, was raised to 1700 inches 
 by the evaporation of the same quantity of water. If the double force, instead of being raised 930 
 inches, had been raised only 850 inches, or half the first elevation, then the mechanical effect evolved 
 would in both cases be precisely the same, the double resistance being raised through only half the 
 space ; but the actual height through which the double resistance is raised being 930 inches instead of 
 850, a greater mechanical effect is produced in the one case than in the other, in the proportion of 930 
 to 850, being an advantage on the part of the steam of greater pressure of about 8 per cent. 
 
 If the pressure under which the evaporation is produced were further varied, it would be found that 
 with every increase of pressure the temperature at which the evaporation would commence would be 
 augmented, and that with every diminution of pressure that temperature would be diminished. It 
 would be also found that the volume of steam produced by a cubic inch of water would be less with 
 every increase of pressure under which the evaporation is made ; and that the diminution of volume 
 would be nearly, but not in quite so great a proportion, as the increase of pressure. In like manner, if 
 the pressure be diminished, the volume of steam produced by a cubic inch of water will be augmented 
 in nearly, but not quite so great a proportion, as that of the diminution of pressure. From all this, it 
 obviously follows that the mechanical effect evolved by the evaporation of a given volume of water 
 under different pressures is very nearly the same ; greater pressures, however, having a slight advan- 
 tage over lesser ones. 
 
 It has been seen that 14f lbs. are raised to a height of 1700 inches by the evaporation of a cubic 
 inch of water under the pressure of 14J lbs. per square inch. Now, 1700 inches are nearly equal tc 
 142 feet ; and 14 j lbs. raised 142 feet is equivalent to 142 times 14| lbs. raised one foot, which is eauaJ 
 
STEAM. 
 
 657 
 
 to very nearly 2100 lbs. raised one foot. To use round numbers, it may then be stated, that by thi 
 evaporation of a cubic inch of water a mechanical force is produced equivalent to a ton weight raised a 
 foot high ; and that this force is very nearly the same, whatever be the temperature or pressure unde; 
 which the evaporation takes place. 
 
 In the following table, calculated by Dr. Lardner, and given by him in the Appendix to the 7th edi- 
 tion of his work on the Steam-Engine, is exhibited the temperatures at which water is evaporated undei 
 different pressures, the volume into which the water expands by evaporation, the mechanical eftec; 
 evolved expressed in lbs. raised one foot. 
 
 1 
 
 Total pressure 
 in pounds per 
 square inch. 
 
 Correspond- 
 ing Tempera- 
 ture. 
 
 Volume of the 
 steam com- 
 pared to the 
 volume of the 
 water that has 
 produced it. 
 
 Mechanical ef- 
 fect of a cubic 
 inch of water 
 evaporated, in 
 pounds raised 
 one foot. 
 
 Total pressure 
 in pounds per 
 square inch. 
 
 Correspond- 
 ing Tempera- 
 ture. 
 
 Volume of the 
 steam com- 
 pared to the 
 volume of the 
 water that has 
 produced it. 
 
 Mechanical ef- 
 fect of a cubic 
 inch of water 
 evaporated, in 
 pounds raised 
 one foot. 
 
 i 
 
 102-9 
 
 20868 
 
 1739 
 
 58 
 
 292-9 
 
 484 
 
 2339 
 
 2 
 
 1261 
 
 10874 
 
 1812 
 
 59 
 
 294-2 
 
 477 
 
 2343 
 
 3 
 
 141-0 
 
 7437 
 
 1859 
 
 60 
 
 295'6 
 
 470 
 
 2347 
 
 4 
 
 152-3 
 
 5685 
 
 1895 
 
 61 
 
 296-9 
 
 463 
 
 2351 
 
 5 
 
 161-4 
 
 4617 
 
 1924 
 
 62 
 
 298-1 
 
 456 
 
 2355 
 
 6 
 
 169-2 
 
 3897 
 
 1948 
 
 63 
 
 299-2 
 
 449 
 
 2359 
 
 7 
 
 175-9 
 
 3376 
 
 1969 
 
 64 
 
 300-3 
 
 443 
 
 2362 
 
 8 
 
 182-0 
 
 2983 
 
 1989 
 
 65 
 
 301-3 
 
 437 
 
 2365 
 
 9 
 
 187-4 
 
 2674 
 
 2006 
 
 66 
 
 302-4 
 
 431 
 
 2369 
 
 10 
 
 192-4 
 
 2426 
 
 2022 
 
 67 
 
 303-4 
 
 425 
 
 2372 
 
 11 
 
 197-0 
 
 2221 
 
 2036 
 
 68 
 
 304-4 
 
 419 
 
 2375 
 
 12 
 
 201-3 
 
 2050 
 
 2050 
 
 69 
 
 305-4 
 
 414 
 
 2378 
 
 13 
 
 205-3 
 
 1904 
 
 2063 
 
 70 
 
 306-4 
 
 408 
 
 2382 
 
 14 
 
 209-1 
 
 1778 
 
 2074 
 
 71 
 
 307-4 
 
 403 
 
 2385 
 
 15 
 
 212-8 
 
 1669 
 
 2086 
 
 72 
 
 308-4 
 
 398 
 
 2388 
 
 16 
 
 216-3 
 
 1573 
 
 2097 
 
 73 
 
 309-3 
 
 393 
 
 2391 
 
 17 
 
 219-6 
 
 1488 
 
 2107 
 
 74 
 
 310-3 
 
 388 
 
 2394 
 
 18 
 
 222*7 
 
 1411 
 
 2117 
 
 75 
 
 311-2 
 
 383 
 
 2397 
 
 19 
 
 225-6 
 
 1343 
 
 2126 
 
 76 
 
 312-2 
 
 379 
 
 2400 
 
 20 
 
 228-5 
 
 12S1 
 
 2135 
 
 77 
 
 313-1 
 
 374 
 
 2403 
 
 21 
 
 231-2 
 
 1225 
 
 2144 
 
 78 
 
 314-0 
 
 370 
 
 2405 
 
 22 
 
 233-8 
 
 1174 
 
 2152 
 
 79 
 
 314-9 
 
 366 
 
 2408 
 
 23 
 
 236-3 
 
 1127 
 
 2160 
 
 80 
 
 315-8 
 
 362 
 
 2411 
 
 24 
 
 238-7 
 
 1084 
 
 2168 
 
 81 
 
 316-7 
 
 358 
 
 2414 
 
 25 
 
 2410 
 
 1044 
 
 2175 
 
 82 
 
 317-6 
 
 354 
 
 2417 
 
 26 
 
 243-3 
 
 1007 
 
 2182 
 
 83 
 
 318-4 
 
 350 
 
 2419 
 
 27 
 
 245'5 
 
 973 
 
 2189 
 
 84 
 
 3193 
 
 346 
 
 2422 
 
 28 
 
 247 6 
 
 941 
 
 2196 
 
 85 
 
 320-1 
 
 342 
 
 2425 
 
 29 
 
 249-6 
 
 911 
 
 2202 
 
 86 
 
 - 32T0 
 
 339 
 
 2427 
 
 30 
 
 251-6 
 
 883 
 
 2209 
 
 87 
 
 321-8 
 
 335 
 
 2430 
 
 31 
 
 253'6 
 
 857 
 
 2215 
 
 88 
 
 322-6 
 
 332 
 
 2432 
 
 32 
 
 255'5 
 
 833 
 
 2221 
 
 89 
 
 323-5 
 
 328 
 
 2435 
 
 33 
 
 257-3 
 
 810 
 
 2226 
 
 90 
 
 324-3 
 
 325 
 
 2438 
 
 34 
 
 259-1 
 
 788 
 
 2232 
 
 91 
 
 325-1 
 
 322 
 
 2440 
 
 35 
 
 260 9 
 
 767 
 
 2238 
 
 92 
 
 325-9 
 
 319 
 
 2443 
 
 36 
 
 262-6 
 
 743 
 
 2243 
 
 93 
 
 326-7 
 
 316 
 
 2445 
 
 37 
 
 264-3 
 
 729 
 
 2248 
 
 94 
 
 327-5 
 
 313 
 
 2448 
 
 38 
 
 265'9 
 
 712 
 
 2253 
 
 95 
 
 328-2 
 
 310 
 
 2450 
 
 39 
 
 267-5 
 
 695 
 
 2259 
 
 96 
 
 329-0 
 
 307 
 
 2453 
 
 40 
 
 269-1 
 
 679 
 
 2226 
 
 97 
 
 329-8 
 
 304 
 
 2455 
 
 41 
 
 270-6 
 
 664 
 
 2268 
 
 98 
 
 330-5 
 
 801 
 
 2457 
 
 42 
 
 272-1 
 
 649 
 
 2273 
 
 99 
 
 33T3 
 
 298 
 
 2460 
 
 43 
 
 273-6 
 
 635 
 
 2278 
 
 100 
 
 332-0 
 
 295 
 
 2462 
 
 44 
 
 275-0 
 
 622 
 
 2282 
 
 110 
 
 339-2 
 
 271 
 
 2486 
 
 45 
 
 276-4 
 
 610 
 
 2287 
 
 120 
 
 345-8 
 
 251 
 
 2507 
 
 46 
 
 277-8 
 
 598 
 
 2291 
 
 130 
 
 352-1 
 
 233 
 
 2527 
 
 47 
 
 279-2 
 
 586 
 
 2296 
 
 140 
 
 357-9 
 
 218 
 
 2545 
 
 48 
 
 280-5 
 
 575 
 
 2300 
 
 150 
 
 363-4 
 
 205 
 
 2561 
 
 49 
 
 281-9 
 
 564 
 
 2304 
 
 160 
 
 368-7 
 
 193 
 
 2577 
 
 50 
 
 283-2 
 
 654 
 
 2308 
 
 170 
 
 373-6 
 
 183 
 
 2593 
 
 51 
 
 284-4 
 
 544 
 
 2312 
 
 180 
 
 378-4 
 
 174 
 
 2608 
 
 52 
 
 285-7 
 
 534 
 
 2316 
 
 190 
 
 382-9 
 
 166 
 
 2622 
 
 53 
 
 286-9 
 
 525 
 
 2320 
 
 200 
 
 387-3 
 
 158 
 
 2636 
 
 54 
 
 288-1 
 
 516 
 
 2324 
 
 210 
 
 391-5 
 
 151 
 
 2650 
 
 55 
 
 289-3 
 
 508 
 
 2327 
 
 220 
 
 395-5 
 
 145 
 
 2663 
 
 56 
 
 290-5 
 
 500 
 
 2331 
 
 230 
 
 399-4 
 
 140 
 
 2675 
 
 67 
 
 291-7 
 
 492 
 
 2335 
 
 240 
 
 403-1 
 
 134 
 
 2687 
 
 You II.— 42 
 
558 
 
 STEAM. 
 
 From what has been above explained, it is apparent that the quantity of sensible heat in steam k> 
 augmented with every increase of pressure under which the evaporation takes place ; but if the interval 
 ef time be observed which elapses between the first application of the lamp to the ice-cold water in 
 the experiment above described, and the moment at which the last particle of water disappears by 
 evaporation from the bottom of the tube, it will be found that this interval is exactly the same, what- 
 ever be the temperature or pressure under which the evaporation takes place. It follows, therefore, 
 that the actual quantity of heat necessary to convert ice-cold water into steam is the same, whatever 
 be the pressure of the steam ; but as the temperature of steam increases and diminishes as the pressure 
 is increased or diminished, it follows that this given quantity of heat is differently distributed between 
 sensible and latent heat in steam of different pressures. As the pressure is increased the sensible heat 
 is augmented, and the latent heat undergoes a corresponding diminution, and vice versa. The sum of 
 the sensible and latent heats is, in fact, a constant quantity; the one being always increased at the ex- 
 pense of the other. It has been shown that in converting water at 32° of temperature, and under a 
 pressure of 14 J lbs. per square inch, it was necessary first to give it 180° additional sensible heat, and 
 afterwards 990° of latent heat, the total heat imparted to it being 1170°. Such, then, is the actual 
 quantity of heat which must be imparted to ice-cold water to convert it into steam. The actual tem- 
 perature to which water would be raised by the heat necessary to evaporate it, if its evaporation could 
 oe prevented by confining it in a close vessel, will be found by adding 32° to 1170°. It may, there- 
 fore, be stated that the heat necessary for the evaporation of ice-cold water is as much as would raise 
 it to the temperature of 1202°, if its evaporation were prevented. If the temperature of red-hot iron 
 be, as is supposed, about 800°, and that all bodies become incandescent at the same temperature, it 
 follows that to evaporate water it is necessary to impart to it 400° more heat than would be sufficient 
 to render it red-hot if its evaporation were prevented. As the mechanical effect evolved by water 
 evaporated at all pressures is nearly the same, and as the quantity of heat necessary to effect that 
 evaporation is also the same, it follows that the same quantity of fuel employed in the evaporation of 
 water is productive of very nearly the same mechanical effect, whatever be the pressure of the steam. 
 
 Since the heat imparted to water in evaporation is necessary to sustain it in the form of vapor, it 
 follows that if any portion of that heat be taken from it, the steam will not be lowered in temperature, 
 but a portion of it will be reconverted into water ; a process which is called condensation. To illustrate 
 this, let us suppose the tube AB to be filled with steam of 212° of temperature, produced from a 
 cubic inch of water evaporated under the pressure of 1-4 J lbs. on the piston. If, by the application of 
 external cold, or any other means, a quantity of heat be extracted from this steam, say as much as 
 would be sufficient to evaporate the tenth of a cubic inch of water, then a tenth part of the steam in 
 the tube will be condensed and deposited in the liquid state in the bottom, the piston will descend 
 through a tenth of its entire height, and the steam remaining uncondensed will still have the tempera- 
 ture of 212° and the pressure of 14J lbs. per square inch, while the water in the bottom of the tube 
 produced by the condensation will also have a temperature of 212°. The heat, therefore, which has 
 been thus abstracted, is the heat which was latent in the steam formed by the water thus deposited. 
 And in the same manner, any heat which is drawn from the steam will be latent heat ; a correspond- 
 ing condensation will take place until all the steam has been condensed, and the piston brought into 
 contact with the bottom of the tube. After that, any abstraction of heat must be made at the expense 
 of the sensible heat of the water. 
 
 It has, in some works, been stated that by mere mechanical compression steam will be converted 
 into water. This is, however, an error, since steam, in whatever state it may exist, must possess at 
 least 212° of heat; and as this quantity of heat is sufficient to maintain it in the vaporous form, under 
 whatever pressure it may be placed, it is clear that no compression or increase of pressure can diminish 
 the actual quantity of heat contained in the steam ; and it cannot, therefore, convert any portion of the 
 steam into water. 
 
 If steam, by mechanical pressure, be forced into a diminished volume, it will undergo an augmenta- 
 tion both of temperature and pressure, the increase of pressure being greater than the diminution of 
 volume ; in fact, any change of volume which it undergoes will be attended with the change of temper- 
 ature and pressure indicated in the above table. The steam, after its volume has been changed, will 
 assume exactly the pressure and temperature which it would have in the same volume if it were im- 
 mediately evolved from water. Thus, let us suppose a cubic inch of water converted into steam under 
 a pressure of 14f lbs. per square inch, and at the temperature of 212°. Let its volume be then reduced 
 by compression in the proportion of 1700 to 930. When so reduced, its temperature will be found to 
 have risen from 212° to 250°, and its pressure will be increased from 14J lbs. per square inch to 29-J 
 lbs. per square inch ; but this is exactly the state, as to pressure, temperature, and density, as the steam 
 would be in if it were immediately raised from water under the pressure of 29^- lbs. per square inch. 
 It appears, therefore, that in whatever manner, after evaporation, the density of steam be changed, 
 whether by expansion or contraction, it will still remain the same as if it were immediately raised from 
 water in its actual state. 
 
 The circumstance which has given rise to the erroneous notion that mere mechanical compression will 
 produce a condensation of steam is, that the vessel in which steam is contained must necessarily have 
 the same temperature as the steam itself. If then the steam contained in the vessel be suddenly com- 
 pressed, it will undergo as sudden an elevation of temperature ; and the vessel containing it not receiv- 
 ing at the same time, from any external source, a corresponding increase of temperature, it will rob the 
 steam of a portion of its heat, and a partial condensation will be produced, and will be continued until 
 the temperatures of the steam and the vessel containing it shall be equalized. 
 
 While water, in passing into steam, suffers a great enlargement of volume, steam, on the other hand, 
 m being converted into water undergoes a corresponding diminution of volume. It has been seen that 
 a cubic inch of water, evaporated at the temperature of 212°, swells into 1700 cubic inches of steam. 
 it follows, therefore, that if a close vessel, containing 1700 cubic inches of such steam, be exposed to 
 
STEAM. 
 
 G59 
 
 cold sufficient to take from the steam all its latent heat, the steam will be reconverted into water, will 
 shrink into its original dimensions, and will leave the remainder of the vessel a vacuum. This prop- 
 erty of steam has supplied the means, in practical mechanics, of obtaining that amount of mecbanieai 
 power which the properties of the atmosphere confer upon a vacuum. If by any means whatever the 
 space in a cylinder under the piston be rendered a vacuum, the atmospheric pressure will take effect 
 above the piston, and will urge the piston downwards with a force amounting to about 15 lbs. on each 
 square inch of the surface of the piston. To render steam available for this purpose, it is only neces- 
 sary to inject it into the cylinder until it expels from the cylinder all the atmospheric air or other un- 
 condensable gases which the cylinder contains ; and when that is effected, the pure steam which remains 
 in the cylinder being suddenly condensed by the application of cold, leaves the cylinder a vacuum, and 
 gives effect to the atmospheric pressure above the piston, as before explained. This is, in fact, the 
 principle of the atmospheric engine. 
 
 The temperature and pressure of steam produced by immediate evaporation, when it has received 
 no heat, save that which it takes from the water, have a fixed relation one to the other. If this rela- 
 tion were known, and expressed by a mathematical formula, the temperature might always be inferred 
 from the pressure, or vice versa. But physical science has not yet supplied any principles by which 
 such a formula can be deduced from any known properties of liquids. In the absence, therefore, of any 
 general relation established by direct reasoning, empyrical formulae have been proposed which express, 
 with more or less precision, this relation in different parts of the thermometric scale. 
 
 When the pressure under which the evaporation takes place does not exceed one atmosphere, or 15 
 lbs. per square inch, the relation between the temperature and the pressure will be expressed with 
 sufficient accuracy by the following formula!, proposed by Southern : 
 
 P 
 
 0-04948 
 
 /51-3 + T\ 5 ' 13 
 \ 155T256 ) 
 
 T = 155-7256 X V P — 0-04948 — 51‘3 , 
 
 where P expresses the pressure in pounds per square inch, and T the temperature by Fahrenheit’s 
 thermometer. 
 
 For pressures exceeding one atmosphere and not exceeding four, the relation is expressed by the 
 following formulas, proposed by Tredgold : 
 
 / 103 + T \ C 
 \ 201-18 / 
 
 T = 201-18 v' _ P — 103; 
 
 or by the following formulae, 
 
 _/98-206 + T\ 6 
 “V 198-562 / 
 
 T = 198-562 l/~Y— 98-806. 
 
 For pressures extending from four to fifty atmospheres, the following formulas have been proposed 
 by Messrs. Dulong and Arago : 
 
 P = (0-26793 + 0-0067585 T) 6 
 T = 147-961 y/T- 39-644. 
 
 Biot has proposed a more general formula, which expresses the relation between the pressure and 
 the temperature, whatever be the pressure under which the evaporation takes place. Let p be the 
 pressure, expressed in millimetres, of mercury at the temperature of melting ice ; let t be the tempera- 
 ture of the water taken on the centesimal air thermometer ; and let a, a,, « 2 , b u h be constant quanti- 
 ties, whose values shall be determined by the following conditions : 
 
 a = 5-96131330259 
 
 Log. a, = 1-82340688193 
 
 Log. b l = — 0-01309734295 
 Log. « a = 0-74110951837 
 
 Log. = — 0-00212510583. 
 
 The relation between p and t will then be expressed by the following formula, 
 
 Log. p = 
 
 ■ a\ bi 
 
 20 + £ 
 
 20 + t. 
 
 M. Biot compared the temperature and corresponding pressures, calculated by this formula, with tho 
 series determined by an extensive course of experiments undertaken by MM. Arago and Dulong by 
 order of the French government, to those of the experiments of Taylor at lower temperatures, and to a 
 numerous series of MSS. observations of M. Gay-Lussac, extending from the boiling point to tempera- 
 tures considerably below that of melting ice, and found that the calculated and observed results cor- 
 responded within the limits of error of the experiments themselves. The formula; first given above 
 offer, however, much greater facility for practical calculation, and afford as accurate results as are re- 
 quired for all ordinary purposes. 
 
 The same difficulty which attends the establishment of a general formula expressing the relation be- 
 tween the temperatures and pressures of steam, also attends the determination of one expressing the 
 relation between the pressure and the augmented volume into which the water expands by evaporation. 
 Empirical formulae have accordingly been likewise proposed to express this relation. The late Pro- 
 fessor Navier proposed the following formula for this purpose. 
 
660 
 
 STEAM. 
 
 Let V express the number of cubic inches of steam produced by one cubic inch of water, and let P 
 express the pressure of this steam in kilograms per square metre ; then we shall have 
 
 _ iooe 
 
 - 0-09 + 0-0000484 ?' 
 
 This formula gives sufficiently accurate results when applied to pressures much above one atmosphere, 
 It fails to give the same accuracy, however, when applied to lower pressures. 
 
 The following formulae have been proposed by M. de Pambour : 
 
 1T _ 10,000 
 
 ~ 0-4227 -f 0-00258 P’ 
 
 which will apply to low pressures ; and 
 
 v _ 10,000 
 
 ~ 1-421 -f (TOO 2 3 P’ 
 
 which will be applicable to high pressures. In each of these P is expressed in pounds per square foot 
 Dr. Lardner proposes the following modified formula, V and P retaining their signification : 
 
 w — 38 ’ 75969 
 ~ 164 + P’ 
 
 which may be used in reference to low-pressure engines of every form, as well as for high-pressure 
 engines which work expansively. 
 
 When the pressure is not less than 30 lbs. per square inch, the following formula will be more 
 accurate : 
 
 _ 434*7826 
 
 ~ 018 4- P' 
 
 In the preceding observations steam has been considered as receiving no heat except that which it 
 takes from the water during the process of evaporation, the amount of which, as has been shown, is 
 1170° more than the heat contained in ice-cold water. But steam, after having been formed from 
 water by evaporation, may, like all other material substances, receive an accession of heat from any 
 external source, and its temperature may thereby.be elevated. If the steam to which such additional 
 heat is imparted be so confined as to be incapable of enlarging its dimensions, the effect produced upon 
 it by the increase of temperature will be an increase of pressure ; but if, on the other hand, it be con- 
 fined under a given pressure, with power to enlarge its volume, subject to the preservation of that 
 pressure, as would be the case if it were contained in a cylinder under a movable piston loaded with a 
 given pressure, then the effect of the augmented temperature will be, not an increase of pressure but 
 an increase of volume ; and the increase of volume in this latter casp will be in exactly the sam , r >- 
 portion as the increase of pressure in the former case. 
 
 These effects of elevated temperature are common, not only to the vapors of all liquids, but also to 
 all permanent gases ; but, what is much more remarkable, the numerical amount of the augmentation 
 of pressure or volume produced by a given increase of temperature is the same for all vapors and gases. 
 If the pressure which any gas or vapor would have were it reduced to the temperature of melting ice 
 be expressed by 100,000, then the pressure which it will receive for every degree of temperature by 
 which it is raised will be expressed by 208 or, what amounts to the same, the additional pressure 
 produced by each degree of temperature will be the 480th part of its pressure at the temperature of 
 melting ice. From these data it is easy to obtain an algebraical expression by which the augmentation 
 of pressure in a given volume, or, what is the same, the augmentation of volume under a given pressure 
 for every increase of temperature, may be calculated. 
 
 Let v be the volume of any elastic fluid at the temperature of 32° ; and let it be then supposed to 
 be raised by the application of heat to the temperature T, if under a given pressure. Let its aug- 
 mented volume be V. The increase of volume will then be Y — v, while the increase of temperature 
 
 V 
 
 will be T° — 32°. But since the increase of volume for one degree of temperature is — -, the increase 
 
 4oU 
 
 for T° - 
 
 ■ 32° will be — — X (T° — 32°) ; and therefore the augmented volume V will be 
 480 v ° 
 
 V = c 4- — (T° — 32°). 
 ' 480 v 
 
 S , , T°-32° ) 
 
 = v \ 1 -j — — - ; 
 
 ( 480 
 
 If Y' be the volume at any other temperature T', we shall have 
 
 V' = * j 
 
 T /0 qoo ) 
 
 480 
 
 From whence we infer 
 
 V T -f- 448 _ 
 
 Y 7- TM- 448’ 
 
 by which, when the volume of steam at any one temperature is known, the volume at any other tem- 
 perature may be found, supposing that the steam receives no accession of water by evaporation. 
 
 Steam which thus receives additional heat after its separation from the water from which it is 
 evolved has been called by Dr. Lardner superheated steam , to distinguish it from common steam, which 
 is that usually employed in steam-engines. Superheated steam admits of losing a part of its heat with- 
 out suffering partial condensation ; but common steam is always partially condensed if any portion ol 
 heat be withdrawn from it. For further details on these properties, see Lardner on the Steam-Emjine 
 7th ed. p. 168, et. seq ; also Appendix. See also Lardner on Heat, chap. viii. ; Cabinet Cyclopccdia, 
 
STEAM. 
 
 661 
 
 In the mechanical operation of steam, ■which has been already explained, the pressure, density, and 
 temperature of the steam are supposed to remain the same during its action, and the mechanical effect 
 is produced by the continual increase of the quantity of steam produced by evaporation. Thus, the 
 piston in the apparatus represented in the figure is moved upwards, not by any change in the tempera- 
 ture, density, or pressure, but by the increased volume required by the continual production of steam. 
 It has been proved that by this process alone the evaporation of a cubic inch of water, whatever be the 
 pressure under which it takes place, evolves a mechanical force equivalent to a ton weight raised a foot 
 high. But if, after this evaporation has been completed, the steam be separated from the water which 
 produced it, and the load on the piston be gradually diminished, the steam would expand by moving 
 the piston upwards in virtue of its excess of pressure, and this expansion will continue until tire press- 
 ure of the steam shall be reduced to equality with the load on the piston. All mechanical effect de- 
 veloped in this process is due to the steam itself, independently of any further evaporation. 
 
 To make this important quality of the expansive action of steam understood, let us suppose the pis- 
 ton loaded with a pressure amounting to four times that of the atmosphere, including that of the at- 
 mosphere itself. If the water under the piston be evaporated under this pressure, it will have a tem- 
 perature of about 291°, and by its evaporation the piston will be raised 40 feet. This will, therefore, 
 be the whole mechanical effect arising from the immediate evaporation of the water. But when the 
 evaporation has been completed, and the piston, with its load of four atmospheres, stands suspended at 
 40 feet above the bottom of the tube, let a pressure equal to that of one atmosphere be removed from 
 the piston. The remaining pressure of three atmospheres being less than that of the steam below the 
 piston, the piston will be raised, and will continue to rise until it has attained a height of about 50 feet, 
 and the temperature of the steam thus expanded will fall to about 275°; and its pressure being re- 
 duced to that of three atmospheres, it will cease to rise. By this process, therefore, a mechanical force 
 has been obtained from the steam equal to the weight of three atmospheres raised 10 feet, in addition 
 to the effect obtained by immediate evaporation ; but the expansive action does not stop here. Let it 
 be supposed that the piston is again relieved from the pressure of another atmosphere, the superior 
 pressure of three atmospheres below will cause it to rise, and it will ascend to the height of about 7 5 
 feet, the temperature of the steam falling to about 250°, and its pressure being reduced to two atmos- 
 pheres. A further mechanical effect equivalent to the weight of two atmospheres raised to about 25 
 feet, has thus been obtained ; and it is evident that by constantly and gradually diminishing the load 
 on the piston, an additional effect may be always obtained from a given amount of evaporation, to an 
 extent which is only limited by practical circumstances which restrain the application of this expansive 
 principle. Since the cost of producing steam as a mechanical agent depends chiefly on the quantity of 
 fuel necessary to effect the evaporation of a given volume of water, it follows that all the mechanical 
 effect obtained by this principle of expansion is so much power added to the steam without further 
 expense. Its importance, therefore, will be obvious in the economy of steam-power. For the manner 
 of rendering it available in steam machinery, see Steam-Engine. 
 
 Table No. 1 exhibits the temperatures and corresponding pressures of steam as determined by the 
 experiments of the committee of the French Institute up to fifty atmospheres — the atmosphere being 
 measured by a column of mercury 29'922 inches high. 
 
 The last six temperatures in table No. 1 are deduced by calculation from the formula c — (1 -f- 
 0-7153 tf, in which e expresses the elasticity in atmospheres, and t the temperatures in centieme de 
 grees, beginning from 100°, and proceeding upwards. 
 
 The most recent experiments on the elastic force 
 of steam are those by a committee of the Franklin 
 Institute. The object of the committee was to in- 
 quire into the causes of the explosion of steam- 
 boilers, to investigate which they were requested 
 to make experiments on the properties of steam, 
 the expense of which was defrayed out of the 
 treasury of the United States. 
 
 The results are contained in the following table, 
 No. 2, arranged as in table No. 1, up to ten atmos- 
 pheres. 
 
 Table II. 
 
 Table I. 
 
 Pressure in 
 Atmospheres. 
 
 Temperature. 
 
 Pressure in 
 Atmospheres. 
 
 Temperature. 
 
 i 
 
 212° 
 
 13 
 
 380-66° 
 
 H 
 
 234 
 
 14 
 
 386-94 
 
 o 
 
 250\5 
 
 15 
 
 392-86 
 
 2i 
 
 263-8 
 
 16 
 
 398-48 
 
 3 
 
 275-2 
 
 17 
 
 403-83 
 
 3* 
 
 285 
 
 18 
 
 408-92 
 
 4 
 
 293-7 
 
 19 
 
 413-78 
 
 44 
 
 300-3 
 
 20 
 
 418-46 
 
 5 
 
 307"5 
 
 21 
 
 422-96 
 
 54 
 
 314-24 
 
 22 
 
 427-28 
 
 6 
 
 320-36 
 
 23 
 
 431-42 
 
 64 
 
 326-26 
 
 24 
 
 435'56 
 
 7 
 
 331-7 
 
 25 
 
 439-34 
 
 n 
 
 336-86 
 
 30 
 
 457-16 
 
 8 
 
 341-78 
 
 35 
 
 472-73 
 
 9 
 
 350-78 
 
 40 
 
 486-59 
 
 10 
 
 358-88 
 
 45 
 
 499-14 
 
 11 
 
 366-85 
 
 50 
 
 510-6 
 
 12 
 
 j 
 
 ‘374 
 
 
 
 Pressure in 
 Atmospheres. 
 
 Temperature. 
 
 Pressure in 
 Atmospheres. 
 
 Temperature. 
 
 i 
 
 212° 
 
 6 
 
 315-J° 
 
 H 
 
 235 
 
 6J 
 
 321 
 
 2 
 
 250 
 
 7 
 
 326 
 
 24 
 
 264 
 
 U 
 
 331 
 
 3 
 
 275 
 
 8 
 
 336 
 
 34 
 
 284 
 
 8| 
 
 340|- 
 
 4 
 
 2914 
 
 9 
 
 345 
 
 4i 
 
 298$ 
 
 94 
 
 349 
 
 5 
 
 304 i 
 
 10 
 
 352 J 
 
 54 
 
 310 
 
 
 
 We add the following table, calculated, we believe, by Professor Alexander, of Baltimore, on the 
 orcssure of steam at various temperatures. 
 
emp 
 
 in 
 
 :gre« 
 
 0 
 
 5 
 
 10 
 
 15 
 
 20 
 
 25 
 
 30 
 
 32 
 
 33 
 
 34 
 
 35 
 
 36 
 
 37 
 
 38 
 
 39 
 
 40 
 
 41 
 
 42 
 
 43 
 
 44 
 
 45 
 
 46 
 
 47 
 
 48 
 
 49 
 
 50 
 
 51 
 
 52 
 
 53 
 
 54 
 
 55 
 
 56 
 
 57 
 
 58 
 
 59 
 
 60 
 
 61 
 
 62 
 
 %3 
 
 64 
 
 65 
 
 66 
 
 67 
 
 68 
 
 69 
 
 70 
 
 71 
 
 72 
 
 73 
 
 74 
 
 75 
 
 76 
 
 77 
 
 78 
 
 79 
 
 80 
 
 81 
 
 82 
 
 83 
 
 84 
 
 85 
 
 86 
 
 87 
 
 88 
 
 89 
 
 90 
 
 STEAM. 
 
 of Steam in inches of Mercury at the temperature of melting ice from degree tt 
 degree of Fahrenheit' s thermometer. 
 
 Difference 
 
 for 
 
 1 degree. 
 
 Temp. 
 
 in 
 
 degrees. 
 
 Pressure in 
 inches of 
 Merc. 
 
 Difference 
 
 for 
 
 1 degree. 
 
 Temp. 
 
 in 
 
 degrees. 
 
 Pressure in 
 inches of 
 Merc. 
 
 Difference 
 
 for 
 
 1 degree. 
 
 0-002 
 
 91 
 
 1-67 
 
 
 157 
 
 9-54 
 
 
 0-003 
 
 92 
 
 1-72 
 
 
 158 
 
 9-76 
 
 
 0-004 
 
 93 
 
 1-77 
 
 0-06 
 
 159 
 
 9-98 
 
 0-23 
 
 0-005 
 
 94 
 
 1-83 
 
 
 160 
 
 10-21 
 
 0-24 
 
 0-006 
 
 95 
 
 1-89 
 
 
 161 
 
 10-45 
 
 
 0-007 
 
 96 
 
 1-95 
 
 
 162 
 
 10-69 
 
 
 0-008 
 
 97 
 
 2-01 
 
 
 163 
 
 10-93 
 
 0-25 
 
 
 98 
 
 2-07 
 
 
 164 
 
 11-18 
 
 
 0-009 
 
 99 
 
 213 
 
 
 165 
 
 11-43 
 
 
 
 100 
 
 2-19 
 
 
 166 
 
 11-68 
 
 0-26 
 
 o-oio 
 
 101 
 
 2-25 
 
 0-07 
 
 167 
 
 11-94 
 
 0-27 
 
 0-011 
 
 102 
 
 2-32 
 
 
 168 
 
 12-21 
 
 
 0-010 
 
 103 
 
 2-39 
 
 
 169 
 
 12-48 
 
 0-28 
 
 o-oii 
 
 104 
 
 2-46 
 
 
 170 
 
 12-76 
 
 
 
 105 
 
 2-53 
 
 
 171 
 
 13-04 
 
 
 
 106 
 
 2-60 
 
 0-08 
 
 172 
 
 13-32 
 
 0-29 
 
 0-012 
 
 107 
 
 2-68 
 
 
 173 
 
 1361 
 
 0-30 
 
 
 108 
 
 2-76 
 
 
 174 
 
 13-91 
 
 
 0-013 
 
 109 
 
 2-84 
 
 
 175 
 
 14-21 
 
 0-31 
 
 0-014 
 
 110 
 
 2-92 
 
 
 176 
 
 14-52 
 
 
 
 111 
 
 3- 
 
 
 177 
 
 14-83 
 
 0-32 
 
 
 112 
 
 308 
 
 009 
 
 178 
 
 15-15 
 
 
 
 113 
 
 3-17 
 
 
 179 
 
 15-47 
 
 0-33 
 
 0-015 
 
 114 
 
 3'-26 
 
 
 180 
 
 15-80 
 
 0-34 
 
 0-016 
 
 115 
 
 3-35 
 
 
 181 
 
 16-14 
 
 
 
 116 
 
 3-44 
 
 
 182 
 
 16-48 
 
 0-35 
 
 0-017 
 
 117 
 
 3-53 
 
 010 
 
 183 
 
 16-83 
 
 
 
 118 
 
 3-63 
 
 
 184 
 
 17-18 
 
 0-36 
 
 0-018 
 
 119 
 
 3-73 
 
 
 185 
 
 17-54 
 
 0-37 
 
 
 120 
 
 3-83 
 
 
 186 
 
 17-91 
 
 
 0-019 
 
 121 
 
 3-93 
 
 0-11 
 
 187 
 
 18-28 
 
 0-38 
 
 
 122 
 
 4-04 
 
 
 188 
 
 18*66 
 
 
 0-020 
 
 123 
 
 415 
 
 
 189 
 
 19-04 
 
 0-39 
 
 0-021 
 
 124 
 
 4"26 
 
 
 190 
 
 19-43 
 
 0-40 
 
 
 125 
 
 4-37 
 
 012 
 
 191 
 
 19-83 
 
 0-41 
 
 0022 
 
 126 
 
 4-48 
 
 
 192 
 
 20-24 
 
 
 0023 
 
 127 
 
 4-60 
 
 
 193 
 
 20-65 
 
 0-42 
 
 
 128 
 
 4-72 
 
 
 194 
 
 21-07 
 
 0-43 
 
 0-024 
 
 129 
 
 4-84 
 
 0-13 
 
 195 
 
 21-50 
 
 
 0-025 
 
 130 
 
 4-97 
 
 
 196 
 
 21-93 
 
 0-44 
 
 0-026 
 
 131 
 
 5-10 
 
 
 197 
 
 22-37 
 
 0-45 
 
 
 132 
 
 5-23 
 
 
 198 
 
 22-82 
 
 
 0-027 
 
 133 
 
 5-36 
 
 014 
 
 199 
 
 23-27 
 
 0-46 
 
 0-028 
 
 134 
 
 5-50 
 
 
 200 
 
 23-73 
 
 0.47 
 
 0-029 
 
 135 
 
 5-64 
 
 
 201 
 
 24-20 
 
 0-48 
 
 
 136 
 
 5-78 
 
 0-15 
 
 202 
 
 24-68 
 
 0-49 
 
 0-030 
 
 137 
 
 5-93 
 
 
 203 
 
 25-17 
 
 
 0-031 
 
 138 
 
 6-08 
 
 
 204 
 
 25-66 
 
 0-50 
 
 0-033 
 
 139 
 
 6-23 
 
 
 205 
 
 26-16 
 
 0-51 
 
 
 140 
 
 6-38 
 
 0-16 
 
 206 
 
 26-67 
 
 0-52 
 
 0-034 
 
 141 
 
 6-54 
 
 
 207 
 
 27-19 
 
 0-53 
 
 0-035 
 
 142 
 
 6-70 
 
 
 208 
 
 27-72 
 
 0-54 
 
 
 143 
 
 6'86 
 
 0-17 
 
 209 
 
 28-26 
 
 0 - 55 
 
 0-037 
 
 144 
 
 7-03 
 
 
 210 
 
 28-80 
 
 
 0-038 
 
 145 
 
 7-20 
 
 0-17 
 
 211 
 
 29-35 
 
 056 
 
 0039 
 
 146 
 
 7-37 
 
 0-18 
 
 212 
 
 29-91 
 
 0-57 
 
 0-040 
 
 147 
 
 ^*55 
 
 
 213 
 
 30-48 
 
 0-58 
 
 
 148 
 
 7-73 
 
 0-19 
 
 214 
 
 31-06 
 
 0-59 
 
 0-043 
 
 149 
 
 7-92 
 
 
 215 
 
 31-65 
 
 0-60 
 
 0-043 
 
 150 
 
 8-11 
 
 
 216 
 
 32-25 
 
 0-61 
 
 0-04 
 
 151 
 
 8*30 
 
 0-20 
 
 217 
 
 32-86 
 
 
 0-05 
 
 152 
 
 8-50 
 
 
 218 
 
 33-47 
 
 0-63 
 
 
 153 
 
 8-70 
 
 
 219 
 
 34-10 
 
 
 
 154 
 
 8-90 
 
 021 
 
 220 
 
 34-73 
 
 0-65 
 
 
 155 
 
 9-11 
 
 
 221 
 
 35-38 
 
 
 
 156 
 
 9-32 
 
 0-22 
 
 009 
 
 36-03 
 
 067 
 
STEAM. 
 
 663 
 
 Temp. 
 
 in 
 
 degrees. 
 
 °23 
 
 224 
 
 225 
 
 226 
 
 227 
 
 228 
 
 229 
 
 230 
 
 231 
 
 232 
 
 233 
 
 234 
 
 235 
 
 236 
 
 237 
 
 238 
 
 239 
 
 240 
 
 241 
 
 242 
 
 243 
 
 244 
 
 245 
 
 246 
 
 247 
 
 248 
 
 249 
 
 250 
 
 251 
 
 252 
 
 253 
 
 254 
 
 255 
 
 256 
 
 257 
 
 258 
 
 259 
 
 260 
 261 
 262 
 
 263 
 
 264 
 
 265 
 
 266 
 
 267 
 
 268 
 
 269 
 
 270 
 
 271 
 
 272 
 
 273 
 
 274 
 
 275 
 
 276 
 
 277 
 
 278 
 
 Table of the Pressure of Steam, dbc., (Continued.) 
 
 Pressure in 
 
 Difference 
 
 Temp. 
 
 Pressure in 
 
 Difference 
 
 Temp. 
 
 Pressure in 
 
 Difference ! 
 
 inches of 
 
 for 
 
 in 
 
 inches of 
 
 for 
 
 in 
 
 inches of 
 
 for 
 
 Merc. 
 
 1 degree. 
 
 degrees. 
 
 Merc. 
 
 1 degree. 
 
 degrees. 
 
 Merc. 
 
 1 degree, j 
 
 36‘70 
 
 
 279 
 
 94-47 
 
 1-50 
 
 335 
 
 213-74 
 
 2-94 
 
 37-37 
 
 0-69 
 
 280 
 
 95-97 
 
 1-51 
 
 336 
 
 216-68 
 
 2-97 
 
 38-06 
 
 0-70 
 
 281 
 
 97-48 
 
 1-52 
 
 337 
 
 219-65 
 
 3- 
 
 38-76 
 
 0-71 
 
 282 
 
 99- 
 
 1-54 
 
 338 
 
 222-65 
 
 3-03 
 
 39-47 
 
 0-72 
 
 283 
 
 10054 
 
 1-56 
 
 339 
 
 225-68 
 
 3-07 
 
 40-19 
 
 0-73 
 
 284 
 
 102-10 
 
 1-58 
 
 340 
 
 228-75 
 
 3-10 
 
 40-92 
 
 0-75 
 
 285 
 
 ] 03*08 
 
 1-60 
 
 341 
 
 231-85 
 
 3-13 
 
 41-67 
 
 
 286 
 
 105-28 
 
 1-63 
 
 342 
 
 234-98 
 
 3-16 
 
 42-42 
 
 0-76 
 
 2S7 
 
 106-91 
 
 1-65 
 
 343 
 
 238-14 
 
 3-20 
 
 43-18 
 
 0-77 
 
 288 
 
 108-56 
 
 1-67 
 
 344 
 
 241-34 
 
 3-24 
 
 4395 
 
 0-78 
 
 289 
 
 110-23 
 
 1-69 
 
 345 
 
 244-58 
 
 3-28 
 
 44-73 
 
 0-80 
 
 290 
 
 111-92 
 
 1-71 
 
 346 
 
 247-86 
 
 3-32 
 
 45’53 
 
 0-81 
 
 291 
 
 113-63 
 
 1-72 
 
 347 
 
 251-18 
 
 3-36 
 
 46-34 
 
 0-82 
 
 292 
 
 115-35 
 
 1-75 
 
 348 
 
 254-54 
 
 3-39 
 
 47-16 
 
 0-83 
 
 293 
 
 117-10 
 
 1-77 
 
 349 
 
 257 93 
 
 3-42 
 
 47-99 
 
 0-85 
 
 294 
 
 118-87 
 
 1-80 
 
 350 
 
 261-35 
 
 3-45 
 
 48-84 
 
 0-86 
 
 295 
 
 120-67 
 
 1-83 
 
 351 
 
 264-80 
 
 3-49 j 
 
 49-70 
 
 0-87 
 
 296 
 
 122-50 
 
 1-85 
 
 352 
 
 268-29 
 
 353 
 
 50’57 
 
 0-88 
 
 297 
 
 124-35 
 
 1-87 
 
 353 
 
 271-82 
 
 3-59 
 
 51-45 
 
 0-89 
 
 298 
 
 126-22 
 
 1-89 
 
 354 
 
 275-39 
 
 361 
 
 52-34 
 
 0-91 
 
 299 
 
 128-11 
 
 1-91 
 
 355 
 
 279- 
 
 366 
 
 53-25 
 
 0-92 
 
 300 
 
 130-02 
 
 1-93 
 
 356 
 
 282-66 
 
 3-71 
 
 54-17 
 
 0-94 
 
 301 
 
 131-95 
 
 1-96 
 
 357 
 
 286-37 
 
 3-75 i 
 
 55-11 
 
 0-95 
 
 302 
 
 133-91 
 
 1-99 
 
 358 
 
 290-12 
 
 3-79 
 
 56-06 
 
 0-96 
 
 303 
 
 135-90 
 
 2-01 
 
 359 
 
 293-91 
 
 3-83 
 
 57-02 
 
 0-97 
 
 304 
 
 137-91 
 
 2-03 
 
 360 
 
 ’297-74 
 
 3-87 
 
 57-99 
 
 1- 
 
 305 
 
 139-94 
 
 2-06 
 
 361 
 
 301-61 
 
 3-91 
 
 58-99 
 
 1-01 
 
 306 
 
 142- 
 
 209 
 
 362 
 
 305'52 
 
 3-95 
 
 60- 
 
 
 307 
 
 144-09 
 
 2-11 
 
 363 
 
 309-47 
 
 3-99 
 
 61-01 
 
 1-03 
 
 308 
 
 146-20 
 
 2-13 
 
 364 
 
 313-46 
 
 4-04 
 
 62-04 
 
 1-04 
 
 309 
 
 148-33 
 
 2-16 
 
 365 
 
 317-50 
 
 
 63-08 
 
 1-07 
 
 1-07 
 
 310 
 
 150-49 
 
 220 
 
 2’22 
 
 
 
 
 64-15 
 
 311 
 
 152-69 
 
 
 
 
 65"22 
 
 1 09 
 
 312 
 
 154-91 
 
 2-24 
 
 
 Formula. 
 
 
 66-31 
 
 
 313 
 
 157-15 
 
 9*27 
 
 
 
 inches. 
 
 67-41 
 
 1-10 
 
 314 
 
 159-42 
 
 2-30 
 
 v — 
 
 pressure in 
 
 68-53 
 
 112 
 
 315 
 
 161-72 
 
 2-32 
 
 t = 
 
 temp, in deg. Fahr. 
 
 69-67 
 
 114 
 
 316 
 
 16404 
 
 2-34 
 
 
 / t 990 \ 0 
 
 70-83 
 
 116 
 
 317 
 
 166-38 
 
 2-37 
 
 .-./> = 
 
 (T80 + 1695) 
 
 71-99 
 
 
 318 
 
 168-75 
 
 2-40 
 
 73-18 
 
 119 
 
 319 
 
 171-15 
 
 2-44 
 
 t 
 
 180 1/ p— 105°, 13. 
 
 74-37 
 
 1-23 
 
 320 
 
 173-59 
 
 2-48 
 
 
 
 75-60 
 
 1-24 
 
 321 
 
 176-07 
 
 2-51 
 
 P‘ = 
 
 
 atmosphere 
 
 76-84 
 
 1-25 
 
 322 
 
 
 o-53 
 
 pressure in 
 
 78-09 
 
 1-27 
 
 323 
 
 181-11 
 
 2'55 
 
 
 of 29*915 inches at 32° 
 
 79-36 
 
 1 28 
 
 324 
 
 183*66 
 
 2-58 
 
 
 r . 
 
 
 80-64 
 
 1 30 
 
 325 
 
 186-24 
 
 2-61 
 
 t 
 
 temp, as before ; 
 
 81-94 
 
 1-33 
 
 326 
 
 188-85 
 
 2 61 
 
 
 / t 561-91 \ c 
 
 83- 27 
 
 84- 61 
 
 1-34 
 
 1-35 
 
 327 
 
 328 
 
 191-49 
 
 194-15 
 
 2-66 
 
 2-69 
 
 
 1 1 
 
 - 9 
 
 • ■ P 
 
 y 317-13 1 
 
 1695 ) 
 
 85-96 
 
 1 36 
 
 329 
 
 196-84 
 
 2-73 
 
 
 ( * , 
 
 \ ft 1 
 
 87-32 
 
 1-39 
 
 330 
 
 
 2-76 
 
 
 990 \ 
 
 88-71 
 
 1-41 
 
 331 
 
 202-33 
 
 2-80 
 
 
 ^317-13 1 
 
 2986-33 / 
 
 9012 
 
 1-43 
 
 332 
 
 205 13 
 
 2-84 
 
 and 
 
 
 
 91-55 
 
 93 
 
 1-45 
 
 1-47 
 
 333 
 
 334 
 
 207-97 
 
 210-84 
 
 2-87 
 
 2-90 
 
 t ~ 
 
 317-13 V p' 
 
 — 105°, 13 
 
 For a more exceuoed and at the same time practical view of the theory of steam and the steam 
 engine, embracing rules for all the calculations likely to be introduced in the practice of constructing ol 
 working steam-engines, the reader cannot do better than consult “Bourne on the Steam-Engine,” put 
 lished by the Artisan Club. It should be in the hands of every one using steam, and Is recommended 
 to our readers as a standard work on this subject. 
 
664 
 
 STEEd. 
 
 STEEL. Steel appears to occupy an intermediate place between cast and malleable iron. The 
 researches of the French academicians, Monge, Barthollet, and Vandermonde, show the distinction 
 between cast-iron and steel to be that the former is charged with a superabundant, the latter with a 
 minute yet sufficient dose of carbon ; hammered iron, on the contrary, if pure, consists of iron free from 
 all heterogeneous matter. It is to be regretted that the constituent proportions of steel have not been 
 accurately determined. Vauquelin assumes the average amount of carbon to be l-150th, and Clouet 
 places it as high as l-32d. Mr. Parkinson considers the quantity of carbon necessary for making of steel 
 to be very small, indeed the actual amount seldom exceeding l-200th, or 1 -300th, and perhaps never 
 more than l-100th, the remaining portion of charcoal flying off at the time of cementation in the 
 form of gaseous oxide of carbon. Dr. Thomson analyzed some specimens of cast-steel, from the man- 
 ufactory of Mr. Buttery, near Glasgow, and the general results of his trials gave the constituents as 
 follows : 
 
 Iron 99 
 
 Carbon, with some silicon 1 
 
 100 
 
 Now this approaches — 
 
 Iron, 20 atoms VO 
 
 Carbon, 1 atom 0’75 
 
 VO-75 
 
 And this Dr. Thomson considers as likely to be the constitution of cast-steel. He did not m like 
 manner attempt the analysis of blistered steel, but concludes the proportion of carbon in it to be rather 
 less. It is well ascertained that iron and carbon are capable of combining together in a variety of 
 different proportions : when the carbon exceeds, the compound is carburet of iron ; when the iron 
 exceeds, the compound is steel or cast-iron in various states according to the proportion : all these com- 
 pounds may be considered as subcarburets of iron. The most complete detail of experiments on these 
 compounds which has yet appeared in this country is by Mr. Mushet. This ingenious metallurgical 
 chemist has observed that the hardness of iron increases with the proportion of charcoal with which it 
 combines, till the carb6n amounts to about l-80th of the whole mass. The hardness is then a maxi- 
 mum, the metal acquires the color of silver, loses its granulated appearance, and assumes a crystallized 
 form. If more carbon be added to the compound the hardness diminishes in proportion to the quantity, 
 as appears from the following tabular arrangement, extracted from Mr. Mushet’s papers on iron 
 and steel : 
 
 Iron, semi-steelified 
 
 Soft steel, capable of welding 
 
 Cast-steel for common purposes 
 
 Cast-steel requiring more hardness 
 
 Steel capable of standing a few blows, but quite unfit for drawing, 
 
 First approach to a steely granulated fracture 
 
 White cast-iron 
 
 Mottled cast-iron 
 
 Carbonated cast-iron 
 
 Super-carbonated crude iron 
 
 contains 1-1 50th of carbon. 
 “ 1-1 20th 
 
 “ l-100th 
 
 “ l-90th 
 
 “ l-50th “ 
 
 „ j 1-3 0th ) 
 
 ( l- 40 th y 
 
 “ 1-2 5 th “ 
 
 “ 1-2 0th 
 
 “ 1-1 5th 
 
 “ 1-1 2th 
 
 Dr. Schafthacutl has lately propounded a novel and startling theory, viz., that steel is entirely a 
 mechanical production of the forge-hammer, which tears the molecules of certain species of white cast- 
 iron out of their original positions, into which the forces of attraction, in respect to the centres as well 
 as to the position of the molecules, had arranged those molecules by the slow action of heat, and that 
 steel, as it comes out of the converting-furnace or the crucible, is nothing more or less than white cast- 
 iron, of which Indian steel, called wootz, is the fairest specimen. 
 
 Steel, as is well known, is made by combining carbon with iron, the atmosphere being excluded and 
 a white heat kept up until the iron has imbibed from the carbonaceous matter with which it is sur- 
 rounded a sufficient quantity, which may be more or less, according to the use for which the steel is 
 intended. Iron is very slightly, and if pure, not at all, altered or increased in hardness by sudden cool- 
 ing from a red-heat, but the small amount of carbon which it receives during the process of cementation 
 greatly increases both its strength and toughness, leaving it alike malleable and ductile, and imparts to 
 it that peculiarly valuable property of becoming extremely hard if suddenly cooled from a red-heat. 
 With this first dose of carbon it is denominated mild steel , possessing all the distinctive properties oi 
 iron with increased strength. A larger dose of carbon renders the metal susceptible of greater hard- 
 ness, and proportionably more brittle. It is also fusible, and therefore called cast-steel, but being less 
 malleable is more difficult to work. 
 
 Steel made by cementation is designated blistered-steel, because it is supposed, while the carbon is 
 entering it meets with oxygen, hydrogen, or some foreign matter which it causes to become gaseous, 
 and thus blisters the surface of the steel. Dr. Thomson attributes these blisters to a gas evolved in the 
 interior of the bar, which pushes up by its elasticity a film of the metal, and Mr. Gill considers them as 
 indications of the quality of the steel, as “ the hardest will be found to be blistered all over its surface 
 while the milder will be smoother.” Cast-steel being made by fusion admits of an equal distribution of 
 the carbon, to the expulsion of every other substance, which cannot endure the intense heat : the sound- 
 ness of this description of steel is obviously a great recommendation, but the excess of carbon renders it 
 
STEEL. 
 
 665 
 
 harsh and consequently intractable ; under the hammer, however, by careful treatment during the 
 operation of forging, the excess of carbon may be dissipated and the quality of the steel ameliorated 
 and greatly improved for general purposes. 
 
 The question whether steel contains any thing besides iron and carbon is purely chemical, the con- 
 sideration of which would form, did space allow, an interesting theoretical illustration of the practical 
 details of the present inquiry. A good workman merely requires steel free from flaws, completely 
 homogeneous, and such as will harden at the lowest heat, for this test supersedes all others in proving 
 its superior quality. 
 
 Perfectly pure iron cemented in equally pure carbon would doubtless produce steel free from blisters, 
 but as in practice these blisters are unavoidably evolved, it is needless to inquire into their origin more 
 minutely than we have already done, especially as it seems to be admitted that blistered-steel is 
 unequally carbonized, the outside retaining the larger portion. It is therefore rendered fit for the 
 market by doubling and welding several times, by which means the parts are more intimately blended 
 together, and the carbon more equally distributed ; in this state it is called sheer-steel. These repeated 
 weldings, although they tend to condense the metal, are apt to produce flaws, 1st. by imperfect union, 
 2d. by the carbon burning out of the commingling surfaces, thereby interposing a stratum of iron or 
 imperfectly converted steel, and this being softer than the surrounding particles would give way during 
 the extension of the steel. To whatever cause such defects are to be attributed must necessarily 
 remain a matter of conjecture, but that they do very largely accompany this description of steel 
 is certain, and it is a question whether any process short of actual fusion can totally remove them ; 
 nevertheless, it is ascertained that long-continued forging essentially conduces to the soundness or 
 homogeneity. 
 
 Besides these flaws there is another obstacle frequently met with in steel : it is said to have pins, 
 when, in the operation of turning or filing, knots are developed harder than the other portions of the 
 metal ; these knots or pins present themselves of almost every degree or hardness, commencing with 
 mere harshness, and advancing to absolute intractability, so that whilst turning in the lathe the pins 
 would remain projecting out and grind or break the edge of the tool rather than submit to be cut away, 
 and it is by no means unusual to find their hardness nearly approach that of a file applied to remove 
 them. Various causes have been assigned for these knots; Mr. Varley thinks they are portions of 
 metal over-steeled, that is, so completely charged with carbon as to be incapable of being annealed by 
 any known process of slow cooling. Mr. Clement states that he broke the steel across these pins, hav- 
 ing filed away the back to render it weak enough to part at the right place, when he found a cut or 
 division, on which account he attributes the flaw and its extreme hardness to an oxide of iron, which 
 prevented the union of the parts. It would be a curious and by no means an unprofitable investiga- 
 tion to analyze the condition of the deepest blisters, in order to determine whether they are alloyed or 
 oxidized, or in any way differing in their state of carbonization from the more solid parts. It seems 
 clear that if these pins are induced by the presence of oxygen, then the adjoining metal would be iron, 
 for there would be a gradation from the oxide through iron to the steel, and consequently the circum- 
 ference of such a spot would be softest. 
 
 An excess of carbon renders steel harder and more brittle, therefore au inequality is liable to occur. 
 This may be illustrated by the known fact, that portions of an iron casting intended to be soft are fre- 
 quently hardened by contact with the moist sand of which the mould is formed, and those parts near- 
 est the outside break with a fracture more glassy than even hard steel. How good steel hardened by 
 sudden immersion in cold water, when at a red-heat, will invariably return to a soft state by slow cool- 
 ing from such heat, and more equally so if the external atmosphere be carefully excluded ; but this 
 hard cast-iron on the contrary does not ; it requires to be exposed for many hours to an intense heat, 
 and must not be smothered by fuel to prevent the escape of the superabundant carbon with which it is 
 charged. The air too should be allowed free access as a means of disengaging some portions of the 
 carbon, while the remainder has a tendency to equalize itself; then, if slowly cooled, the mass will be 
 found to be sufficiently aunealed. 
 
 The knots or pins in steel are rarely removed by slow cooling alone ; there is, however, an opinion 
 prevalent among workmen that pinny steel may be rendered uniform in its substance if it be first 
 hardened and then annealed. To bum out these pins would manifestly spoil the steel, because it has 
 no carbon to spare but in the pins, (supposing this to be the cause of their hardness,) and the process 
 of annealing in air-tight vessels is not found to produce equality sufficient for any good purpose. Even 
 cast-steel, which is undeniably purer and more homogeneous than any other description, is liable to 
 long streaks or veins harder than the other portions of the bar. All these show the necessity of greater 
 and more minute attention to the treatment of steel than the subject appears to have received, and for 
 this end two modes of hammering are indispensable. To illustrate our position, let us take any article 
 forged in the usual way, not out of blistered or sheer-steel, both of which may be presumed to contain 
 carbon unequally distributed, but of cast-steel, which having been fused and passed through the rolls, 
 or under a jjonderous tilt-hammer, is characterized as refined, and considered uniform. Yet notwith- 
 standing every precaution, we still see the labor and skill of the machinist defeated by those veins, 
 fissures, and pins, which denote either metal of inferior quality, or that the original texture of the steel 
 has been deteriorated by the ignorance and carelessness of the smith. The first supposition does not 
 apply to cast-steel, in which the dose of carbon is diffused equally throughout the mass, or so nearly so 
 as to render the difference inappreciable. We are therefore compelled to admit the second position, 
 and this, unless we have entirely mistaken the bearings of the case, will enable us to account for past 
 failures and guard against future disappointment. 
 
 The two-fold process of hammering, already alluded to, is intended to correct the greater part, if not 
 the whole, of the defects pointed out. It is necessary in the first place to hammer the steel at a forg- 
 ing heat, so as to knead the parts together and keep them moving among themselves. This should bo 
 continued till the different constituents are not only intimately blended, but as it were dissolved iu each 
 
( 1(36 
 
 STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 other, so as to insure perfect uniformity, for the carbon being thus spread the metal will be rendered 
 as sound as can be expected of cemented steel ; and it is clear that if by mechanical agency all foreign 
 matter be expelled and the carbon alone remain, there is nothing to prevent a perfect union of the parti 
 while under the hammer. Good steel consists of that proportion of carbon and iron, which combined 
 form the strongest and toughest compound ; each purer portion, therefore, when brought into contact by 
 the hammer remains in that state and resists its percussive force the more from the greater cohesion of 
 the particles. Hence the redundant or deficient portions suffer most till they become equalized, and 
 the impurities are either beaten out or formed into a homogeneal compound with the entire mass. 
 
 Although by this means sound steel may be obtained, it is far from being in a perfect state ; it is still 
 very unequal in density, and in a state of distraction ; some portions are close and dense, and others are 
 fissured. A second hammering at a particular heat is therefore necessary, and under circumstances 
 required by the shape of the steel — such as recesses in the anvil or blocks laid thereon, technically 
 termed swedges and moulds. For this purpose the metal is first brought as near as eligible to the re- 
 quired dimensions, and is then to be hammered in order to close and condense the particles equally 
 and throughout, yet leaving every part in a state of rest and ease — a condition very essential for good 
 springs, and indeed every article formed of steel, that has to vibrate or act by tension. 
 
 This second hammering is also intended to prepare the steel for receiving the utmost hardness of 
 which it is susceptible — a quality which entitles it to be considered the master metal — the one by which 
 we give shape and form to all others. How steel at a red-heat, when suddenly plunged in cold water, 
 becomes both brittle and hard, but even in this state its toughness greatly exceeds that of any other 
 brittle substance. This characteristic hardness cannot be given in part, but always in full and to its 
 highest limit. So true is this, that in a piece of steel, a portion of which is hard and a portion soft, no 
 gradation of hardness can be detected, the parts adjacent to the hard portion being quite soft, or, as 
 some think, softer than if slowly cooled. This singular fact has been thus accounted for : — Suppose a 
 rod of well-hammered steel to be heated at one end for hardening, there will be a gradation of tem- 
 perature from the coldest to the hottest extremity, and the annealing or reduction of that hardness 
 which it has received will be in proportion to the heat, consequently the rod will be softer and softer 
 towards the end where the heat is applied. On plunging the bar into cold water, that portion which 
 has become sufficiently hot to harden, is rendered quite hard, but that part immediately adjacent to it 
 will be found to be most annealed, and will endure more twisting and bending than any other. Al- 
 though this hardness may be imparted in its full extent, it may nevertheless be lowered in any assigna- 
 ble degree — that is, a portion of its brittleness may be removed by the application of moderate heat, a 
 greater portion by more heat, and so on, as the purposes may require. This is called tempering. If 
 hard steel be brought to a red-heat and then suffered to cool slowly, it will become as soft as if never 
 hardened : this is called softening , and is distinguished from annealing , which is a similar process of 
 slow cooling, but applied to steel, iron, or brass, merely to remove all mechanical condensation, whether 
 by hammering or otherwise ; for if metal has been altered in shape by the hammer or any other pro- 
 cess, as much as it will bear without breaking, then by annealing it will be softened and may again be 
 altered in form as often as requisite. Now as different degrees of heat remove different degrees of 
 condensation received from the hammer, and a white-heat removes all, it is of great importance to 
 harden steel from the lowest possible degree of heat, in order to retain as much condensation as practi- 
 cable ; and it is a fortunate coincidence that the greater the condensation the lower is the heat from 
 which steel will harden, and the stronger and tougher it will be. But should this condensed metal be 
 once over-heated, it will then no longer harden from that lower degree, but only from a heat nearly 
 approaching that to which it was originally raised. In this case, the condensation, with all its attend- 
 ant advantages, can only be restored by rehammering. 
 
 The lowest heat at which steel will generally harden, is a dull or cherry -red, just visible in day-light ; 
 therefore, to be safe, the same test, that is, a dull red-heat, just perceptible in the dark, is chosen for 
 the process of hammering ; it offers, too, the advantage of coating the article with carbonaceous matter, 
 thereby securing instead of losing by the action of the fire a due supply of carbon, which is of particu- 
 lar consequence. Different modes of performing this part of the process may be adopted. It is de- 
 sirable that the forge should not be under the influence of a strong light; the anvil should be placed as 
 near as circumstances will permit to the flat bed of the forge, and the fire smothered with small fuel, 
 just kept alive by the bellows, so as never to allow the gas bursting into flame. The pieces of steel 
 under treatment are now placed in the smouldering and partially kindled fuel enveloped in smoke, 
 whence they imbibe a portion of carbon, which the hammering heat is insufficient to expel ; they are 
 then brought in succession from the fire to the anvil, and back again to the fire when too cool, the ham- 
 mer is moved quickly, and every part of the steel subjected to its blow. The position of the article is 
 then slightly changed, and the operation continued and repeated as often as needful, till it has been 
 hammered well in every direction. See Tools, as also Tempering. See also Mushet on Steel. 
 
 STRENGTH OF MATERIALS OF CONSTRUCTION. 1. Direct cohesion.— The power of co- 
 hesion is that resistance which bodies exhibit when force or weight is applied to tear asunder in the 
 direction of their length the fibres or particles of which they are composed. 
 
 The strength to resist force or weight that produce fracture is as the area of the cross-section acted 
 upon. Hence, multiply the area of the section in inches by the power in pounds (as in the following 
 table) opposite the name of the material, and the product will be equal to the weight in pounds the rod, 
 bar, or piece will just support; but the greatest constant load should never exceed one-fourth. 
 
STRENGTH OP MATERIALS OF CONSTRUCTION. 
 
 667 
 
 Table of the Cohesive Power of Bodies whose Cross-Sectional Areas equal One Square Inch. 
 
 Woods. 
 
 Cohesive 
 Power, 
 in lbs. 
 
 Cohesive 
 Power, 
 in tons. 
 
 Metals. 
 
 Cohesive 
 Power, 
 in lbs. 
 
 Cohesive 
 Power, 
 in tons. 
 
 
 23,400 
 
 10-44 
 
 Swedish bar-iron 
 
 65,000 
 
 29'20 
 
 
 19 980 
 
 8-92 
 
 Russian do 
 
 59,470 
 
 26'70 
 
 Turtosa, African teak. 
 
 17*000 
 
 7'58 
 
 English do 
 
 56,000 
 
 25'00 
 
 Ash 
 
 15,780 
 
 7'04 
 
 Cast steel 
 
 134,256 
 
 59-93 
 
 Teak wood, or Indian 
 
 
 
 Blistered steel 
 
 133,152 
 
 59-43 
 
 
 14,500 
 
 647 
 
 Shear do 
 
 127,632 
 
 56-97 
 
 Poona, or Peon 
 
 1 2^350 
 
 551 
 
 Wrought copper 
 
 33,892 
 
 15-08 
 
 
 12,000 
 
 5-35 
 
 Hard cun-metal 
 
 36,368 
 
 16-23 
 
 American fir, or pine. . 
 
 11,800 
 
 526 
 
 Cast copper 
 
 19,072 
 
 8-51 
 
 Oak 
 
 11,592 
 
 5-17 
 
 Yellow brass, cast 
 
 17,968 
 
 8-01 
 
 
 11 500 
 
 5-13 
 
 Cast-iron 
 
 17,628 
 
 7-87 
 
 Mahogany, Honduras. 
 
 11,475 
 
 5'12 
 
 Tin, cast 
 
 4,736 
 
 211 
 
 
 11,000 
 
 4-91 
 
 Bismuth, cast 
 
 3,250 
 
 1-45 
 
 Chestnut, Spanish 
 
 10,800 
 
 4-82 
 
 Lead, cast 
 
 1,824 
 
 0-81 
 
 Alder 
 
 9,700 
 
 4'33 
 
 Elastic power, or direct 
 
 
 
 Larch 
 
 9,500 
 
 4'24 
 
 tension of wrought- 
 
 
 
 Walnut 
 
 7,740 
 
 3'45 
 
 iron, medium qual- 
 
 
 
 Mahogany, Spanish ... 
 
 7,560 
 
 3'37 
 
 ity 
 
 22,400 
 
 10-00 
 
 Cedar, Libanus 
 
 7,000 
 
 312 
 
 
 
 
 Poplar 
 
 6,500 
 
 2'90 
 
 
 
 
 Note. — A bar of iron is extended '000096, or nearly one ten-thousandth part of its length, for every 
 ton of direct strain per square inch of sectional area. 
 
 The resistance being proportional to the area, the strength of any given bar or bolt will be found by 
 multiplying the sectional area in inches by the tabular number. 
 
 Table of the relative Weight and Strength of Ropes and Chains. 
 
 Cireum. of 
 Rope. 
 
 Weight per 
 fathom. 
 
 Weight of 
 chain per fath. 
 
 Proof 
 
 Strength. 
 
 Cireum. of 
 rope. 
 
 Weight per 
 fathom. 
 
 Weight of 
 chain per fath. 
 
 Proof 
 
 Strength. 
 
 Inches. 
 
 lbs. 
 
 lbs. 
 
 tons. 
 
 cwt. 
 
 Inches. 
 
 lbs. 
 
 lbs. 
 
 tons. 
 
 cwi. 
 
 H 
 
 2} 
 
 54 
 
 1 
 
 54 
 
 10 
 
 23 
 
 43 
 
 10 
 
 0 
 
 44 
 
 4 | 
 
 8 
 
 1 
 
 16| 
 
 104 
 
 28 
 
 49 
 
 11 
 
 11 
 
 5 
 
 H 
 
 lOJ 
 
 2 
 
 10 
 
 114 
 
 304 
 
 56 
 
 13 
 
 8 
 
 5J 
 
 7 
 
 14 
 
 3 
 
 54 
 
 124 
 
 36 
 
 63 
 
 14 
 
 18 
 
 64 
 
 94 
 
 18 
 
 4 
 
 34 
 
 13 
 
 39 
 
 71 
 
 16 
 
 14 
 
 7 
 
 HI 
 
 22 
 
 5 
 
 2 
 
 134 
 
 45 
 
 79 
 
 18 
 
 11 
 
 8 
 
 15 
 
 27 
 
 6 
 
 44 
 
 144 
 
 484 
 
 87 
 
 20 
 
 8 
 
 
 19 
 
 32 
 
 7 
 
 7 
 
 154 
 
 56 
 
 96 
 
 OO 
 
 13 
 
 94 
 
 21 
 
 37 
 
 8 
 
 134 
 
 16 
 
 60 
 
 106 
 
 24 
 
 18 
 
 2. Transverse strength, or resistance to lateral pressure . — The strength of bodies to resist fracture in 
 this direction is as the breadth and square of the depth, directly, and inversely as the length. 
 
 The general formula being 
 
 Sad~ = l w, 
 
 where a is the breadth, d the depth, l the length, w the weight, and S a number determined by experi- 
 ment on ditferent materials. When the beam is supported at each end and loaded in the middle, the 
 values of S for different materials have been determined by Mr. Barlow as in the following table — the 
 breadth and depth being taken in inches, the length in feet, and the weight in pounds. 
 
 Values of S for 
 
 Elastic strength of 
 
 Good English malleable iron 2050 
 
 Cast-iron 2548 
 
 Teak 820 
 
 English oak 400 
 
 Best Canadian 688 
 
 Ash 675 
 
 different Materials. 
 Elastic strength of 
 
 Pitch pine 544 
 
 Red pine 447 
 
 Riga fir 376 
 
 Mar forest fir 415 
 
 Larch 280 
 
 Note. — It must be observed that these numbers indicate the extreme strengdL The practical man 
 must not depend upon more than a third of these values. 
 
868 
 
 STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 If the depth is taken, a certain fractional part of the depth as - th, the above formula becomes 
 
 S d 3 — n l w, 
 
 ,nl 10 
 
 or, d = V- 
 
 Hence the following rule in words : 
 
 Rule. — Multiply the length between the bearing in feet by the weight to be supported in pounds 
 and by the number indicating the ratio of the depth to the breadth — divide the product by the tabular 
 value, and the cube root of the quotient equals the dejith in inches ; and the depth divided by the pro- 
 portional breadth is the breadth in inches. 
 
 Example. — Suppose a uniform beam of cast-iron, 18 feet in length, be required to carry a weight of 
 20,000 pounds on the middle, between the supports, what must be the breadth and depth, in inches, 
 when the breadth is one-fifth of the depth, and the strain not to exceed one-third of the strength ? 
 
 We must here take ^s = 850. 
 
 88 X 20000 X 5 l'^*8 
 
 Hence, = 3 */ 2117'6 = 12'8 in. in depth, and — ' — = 2'56 in. in breadth or thickness. 
 
 850 5 
 
 2. Given the length and breadtlt of a uniform beam, and the weight it is to support in the middle , to 
 find the required depth ; or the depth given, to find the breadth required. 
 
 Here, d = — . 
 
 s a 
 
 Rule. — Multiply the length in feet by the weight in pounds. Also the tabular value of S by the 
 breadth in inches. Divide the former product by the latter, and the square root of the quotient will 
 give the depth in inches. 
 
 Or, divide the former product by S times the square of the depth, and the quotient will be the 
 breadth. 
 
 Example. — Let it be required to find the breadth of a uniform beam of oak to sustain a weight of 
 6000 pounds in the middle of its length, the distance between the supports being 20 feet, and the depth 
 of the beam 9 inches. The strain to be half the strength. 
 
 G000 X 20 
 
 : 7 '4 inches, the breadth ; and 
 
 V 6000 X 20 
 
 = 9-1 inches, the depth. 
 
 200 X 9- ’ ' ~~ ’ " 200 X 7 
 
 Note 1. — When the load is not on the middle of the beam, but placed nearer to one end, divide four 
 times the product of the distance of the weight in feet from each bearing by the whole distance in feet, 
 and the quotient equals the length of the beam to be taken into account. 
 
 Example. — Suppose a beam 80 feet in length with a load placed 9 feet from one end ; required the 
 length to be taken into calculation as affected by the load. 
 
 21 X 9 X 4 
 
 30 — 9 = 21, and = 25'2 feet effective length. 
 
 30 ° 
 
 Note 2, — When the load is distributed over the whole length of a beam, it will bear double the as- 
 sumed load as above ; hence, in such cases, the divisors must be doubled. 
 
 Note 8. — When a beam is to be fixed at one end and the weight placed on the other, take only one- 
 fourth of the tabular number for the divisor; but if the weight is to be laid uniformly along its whole 
 length, use one-half. 
 
 Example to Rule 2. — Required the depth for the cantilevers of a balcony of cast-iron to project 4 feet, 
 and to be placed 5 feet apart, the weight of the stone part being 1000 pounds, the breadth of each can- 
 tilever 2 inches, and the greatest possible load that can be collected upon 5 feet in length of the balcony 
 2200 pounds. 
 
 1000 + 2200 = 3200 lbs.; and 800 = 2 = 400, the divisor. 
 
 Hence, 
 
 V 3200 X 4 . , , , , 
 
 = 4 inches, the depth required. 
 
 400 X 2 
 
 Deflection of rectangular beams.— To ascertain the amount of deflexion of a uniform beam of cast-iron 
 supported at both ends, and loaded in the middle to the extent of its elastic force. 
 
 Rule. — Multiply the square of the length in feet by - 02, and the product divided by the depth in 
 inches equals the deflexion. 
 
 Example . — Required the deflexion of a cast-iron beam 18 feet long between the supports, 12’8 inches 
 deep, 2'56 inches in breadth, and bearing a weight of 20,000 pounds in the middle of its length. 
 
 18 2 X '02 
 
 7 = 506 inches from a straight line in the middle. 
 
 12-8 
 
 Note. — For beams of a similar description, loaded uniformly, the rule is the same, onl) multiply by 
 025 in place of '02. 
 
 To find the deflexion of a beam when fixed at one end and loaded at th e other. 
 
 Rule. — Divide the length in feet of the fixed part of the beam by the length in feet of the part which 
 yields to the force, and add 1 to the quotient ; then multiply the square of the length in feet by the 
 quotient so increased, and also by T3 ; divide this product by the middle depth in inches, and the quo- 
 tient will be the deflexion, in inches also. 
 
 Multiply the deflexion so obtained for cast-iron by -86, the product equals the deflexion for wrought 
 iron ; for oak, multiply by 2'8 ; and for fir, 2'4. 
 
STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 (169 
 
 A Table of the Depths of Square Beams or Bars of Cast-Iron, calculated to support from 1 cwt. to 1* 
 tons in the Middle, the Deflexion not to exceed 1-40 th of an inch for each foot in Length,. 
 
 Lengths in feet. 
 
 4 
 
 6 
 
 8 
 
 10 
 
 12 
 
 14 
 
 16 
 
 i8 
 
 20 
 
 22 
 
 24 
 
 26 
 
 28 
 
 30 
 
 Weight 
 
 Weight 
 
 i 
 
 5 
 
 f 
 
 
 a 
 
 4 
 
 4 
 
 4 
 
 5 
 
 CL 
 
 s 
 
 i 
 
 5 
 
 5 
 
 ft 
 
 in cwt. 
 
 in lbs. 
 
 a 
 
 o 
 
 a 
 
 a 
 
 a 
 
 a 
 
 a 
 
 a 
 
 a 
 
 a 
 
 a 
 
 « 
 
 « 
 
 a 
 
 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 1 cwt. 
 
 112 
 
 1-2 
 
 1-4 
 
 1-7 
 
 1-9 
 
 2-0 
 
 2-2 
 
 24 
 
 2-5 
 
 29 
 
 27 
 
 29 
 
 39 
 
 31 
 
 3-2 
 
 2 
 
 124 
 
 1'4 
 
 1-7 
 
 29 
 
 2'2 
 
 2-4 
 
 2-6 
 
 2-8 
 
 39 
 
 3-1 
 
 39 
 
 3-4 
 
 39 
 
 37 
 
 3-8 
 
 3 
 
 336 
 
 16 
 
 1-9 
 
 2-2 
 
 2-4 
 
 27 
 
 29 
 
 31 
 
 39 
 
 3-4 
 
 39 
 
 3-8 
 
 39 
 
 41 
 
 4*2 
 
 4 
 
 448 
 
 1-7 
 
 2-0 
 
 2-4 
 
 2'6 
 
 29 
 
 3-1 
 
 39 
 
 3-5 
 
 37 
 
 39 
 
 4*0 
 
 42 
 
 43 
 
 4-5 
 
 r> 
 
 560 
 
 1-8 
 
 2'2 
 
 2*5 
 
 28 
 
 3-0 
 
 39 
 
 35 
 
 37 
 
 39 
 
 41 
 
 43 
 
 4-4 
 
 4*6 
 
 4-8 
 
 G 
 
 672 
 
 1'8 
 
 2'2 
 
 2-0 
 
 29 
 
 32 
 
 34 
 
 37 
 
 39 
 
 41 
 
 49 
 
 45 
 
 46 
 
 4-8 
 
 59 
 
 7 
 
 784 
 
 1-9 
 
 23 
 
 2'7 
 
 30 
 
 33 
 
 39 
 
 3-8 
 
 41 
 
 4-2 
 
 4-4 
 
 49 
 
 4-8 
 
 59 
 
 5-2 
 
 8 
 
 896 
 
 2-0 
 
 2-4 
 
 2'8 
 
 31 
 
 34 
 
 37 
 
 3-9 
 
 4-2 
 
 4'4 
 
 49 
 
 48 
 
 59 
 
 59 
 
 54 
 
 9 
 
 1,008 
 
 2-0 
 
 2-5 
 
 2-9 
 
 32 
 
 35 
 
 3-8 
 
 4 0 
 
 49 
 
 49 
 
 47 
 
 4-9 
 
 5-1 
 
 59 
 
 5-5 
 
 10 
 
 1,120 
 
 21 
 
 26 
 
 30 
 
 3'3 
 
 36 
 
 39 
 
 4-2 
 
 44 
 
 47 
 
 49 
 
 5*2 
 
 59 
 
 5'4 
 
 57 
 
 11 
 
 1,232 
 
 2-1 
 
 2'6 
 
 30 
 
 34 
 
 37 
 
 40 
 
 4‘3 
 
 4 5 
 
 4-8 
 
 59 
 
 59 
 
 5*4 
 
 59 
 
 58 
 
 12 
 
 1,344 
 
 2-2 
 
 2'7 
 
 3'1 
 
 35 
 
 3-8 
 
 41 
 
 4’4 
 
 47 
 
 4‘9 
 
 5-1 
 
 5-3 
 
 55 
 
 57 
 
 59 
 
 13 
 
 1,456 
 
 2*2 
 
 2-7 
 
 31 
 
 35 
 
 3-8 
 
 42 
 
 4'4 
 
 47 
 
 49 
 
 5*2 
 
 54 
 
 59 
 
 59 
 
 69 
 
 14 
 
 1,568 
 
 23 
 
 2'8 
 
 3-2 
 
 3'6 
 
 39 
 
 4'2 
 
 45 
 
 4-8 
 
 5*0 
 
 59 
 
 5-5 
 
 57 
 
 6-0 
 
 6-1 
 
 15 
 
 1,680 
 
 23 
 
 2'8 
 
 3'2 
 
 36 
 
 4-0 
 
 49 
 
 46 
 
 49 
 
 5*2 
 
 5*4 
 
 5'6 
 
 58 
 
 6-1 
 
 0-2 
 
 16 
 
 1,792 
 
 2-4 
 
 2-9 
 
 3'3 
 
 37 
 
 4-0 
 
 4-4 
 
 47 
 
 59 
 
 52 
 
 5-5 
 
 57 
 
 59 
 
 6'2 
 
 6*4 
 
 17 
 
 1,904 
 
 2'4 
 
 29 
 
 3’4 
 
 3'8 
 
 4-1 
 
 44 
 
 47 
 
 59 
 
 59 
 
 5-5 
 
 5'8 
 
 6*0 
 
 6’2 
 
 6-5 
 
 18 
 
 2,016 
 
 2-4 
 
 30 
 
 34 
 
 3-8 
 
 42 
 
 45 
 
 4'8 
 
 57 
 
 5-4 
 
 59 
 
 59 
 
 6-1 
 
 04 
 
 6*6 
 
 19 
 
 2,128 
 
 2-5 
 
 3-0 
 
 3-5 
 
 39 
 
 42 
 
 49 
 
 4’9 
 
 59 
 
 5'4 
 
 57 
 
 69 
 
 6-2 
 
 6'5 
 
 6 7 
 
 1 ton. 
 
 2,240 
 
 2-5 
 
 3-0 
 
 3'5 
 
 3-9 
 
 4-3 
 
 49 
 
 49 
 
 5-2 
 
 5'5 
 
 5-8 
 
 6*0 
 
 69 
 
 65 
 
 6*6 
 
 H 
 
 2,800 
 
 2-0 
 
 3'2 
 
 37 
 
 4-1 
 
 45 
 
 49 
 
 5‘2 
 
 5'5 
 
 5-8 
 
 61 
 
 6*4 
 
 69 
 
 69 
 
 7-2 
 
 4 
 
 3,360 
 
 2-8 
 
 34 
 
 39 
 
 4-3 
 
 47 
 
 57 
 
 5'5 
 
 5-8 
 
 O'l 
 
 64 
 
 6*7 
 
 79 
 
 7*2 
 
 7-5 
 
 1-1 
 
 3,920 
 
 2-9 
 
 3-5 
 
 4*0 
 
 4-5 
 
 4-9 
 
 59 
 
 57 
 
 69 
 
 69 
 
 07 
 
 69 
 
 7-2 
 
 7'5 
 
 77 
 
 2 
 
 4.480 
 
 2-9 
 
 35 
 
 41 
 
 47 
 
 57 
 
 5'5 
 
 59 
 
 6*2 
 
 69 
 
 6-8 
 
 7-2 
 
 7-6 
 
 77 
 
 89 
 
 24 
 
 5,600 
 
 31 
 
 3'8 
 
 44 
 
 4-9 
 
 55 
 
 5’8 
 
 G'2 
 
 6*6 
 
 6*9 
 
 79 
 
 7-6 
 
 79 
 
 8'2 
 
 8-5 
 
 3 
 
 6,720 
 
 3-3 
 
 40 
 
 4'6 
 
 51 
 
 57 
 
 67 
 
 6’5 
 
 69 
 
 7’3 
 
 79 
 
 79 
 
 8-3 
 
 89 
 
 89 
 
 34 
 
 7,840 
 
 3-4 
 
 4-1 
 
 4'8 
 
 53 
 
 5-8 
 
 69 
 
 67 
 
 71 
 
 7'5 
 
 79 
 
 8-2 
 
 89 
 
 89 
 
 9'2 
 
 4 
 
 8,960 
 
 35 
 
 43 
 
 4'9 
 
 5*5 
 
 60 
 
 65 
 
 79 
 
 7-4 
 
 7'8 
 
 8-2 
 
 8'5 
 
 89 
 
 9*2 
 
 9 5 
 
 44 
 
 10,080 
 
 
 4-4 
 
 5-1 
 
 57 
 
 62 
 
 67 
 
 7*2 
 
 79 
 
 89 
 
 8-4 
 
 8-8 
 
 9-1 
 
 9-5 
 
 9-8 
 
 5 
 
 11,200 
 
 
 4'5 
 
 5-2 
 
 5.8 
 
 64 
 
 6'9 
 
 7’4 
 
 78 
 
 8‘2 
 
 89 
 
 9*0 
 
 9-4 
 
 97 
 
 107 
 
 6 
 
 13,440 
 
 
 
 55 
 
 6-1 
 
 67 
 
 7-2 
 
 7.7 
 
 8-2 
 
 8'6 
 
 9*0 
 
 9-4 
 
 9-8 
 
 10-2 
 
 10*5 
 
 7 
 
 15,680 
 
 
 
 57 
 
 6-3 
 
 69 
 
 7*5 
 
 89 
 
 8-5 
 
 89 
 
 9*4 
 
 9-8 
 
 10-2 
 
 109 
 
 119 
 
 8 
 
 17,920 
 
 
 
 59 
 
 66 
 
 7 2 
 
 7-8 
 
 89 
 
 8-8 
 
 99 
 
 97 
 
 10-1 
 
 10*6 
 
 109 
 
 119 
 
 9 
 
 20,160 
 
 
 
 6*0 
 
 6-8 
 
 7-4 
 
 89 
 
 89 
 
 90 
 
 9-5 
 
 100 
 
 104 
 
 109 
 
 119 
 
 117 
 
 in 
 
 22,400 
 
 
 
 
 6-9 
 
 7-6 
 
 82 
 
 8-8 
 
 99 
 
 9-8 
 
 109 
 
 107 
 
 11-2 
 
 119 
 
 129 
 
 n 
 
 24,640 
 
 
 
 
 7-1 
 
 7-8 
 
 8-4 
 
 99 
 
 9-5 
 
 10 0 
 
 105 
 
 119 
 
 115 
 
 119 
 
 129 
 
 12 
 
 26,880 
 
 
 
 
 7-2 
 
 79 
 
 89 
 
 9*2 
 
 97 
 
 10*2 
 
 10-8 
 
 11*2 
 
 117 
 
 12-1 
 
 12-5 
 
 13 
 
 29,120 
 
 
 
 
 7-4 
 
 8-1 
 
 88 
 
 9 4 
 
 99 
 
 10*4 
 
 119 
 
 145 
 
 11*9 
 
 12-4 
 
 129 
 
 14 
 
 31,360 
 
 
 
 
 7-5 
 
 8-3 
 
 8-9 
 
 9-5 
 
 10-4 
 
 109 
 
 111 
 
 117 
 
 12-1 
 
 129 
 
 139 
 
 Deflexion in inches. . 
 
 I 
 
 •15 
 
 ■2 
 
 •25 
 
 ■3 
 
 •35 
 
 ■4 
 
 •45 
 
 •5 
 
 •55 
 
 9 
 
 •65 
 
 7 
 
 75 
 
 Lengths in feet. 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 20 
 
 22 
 
 24 
 
 2G 
 
 23 
 
 30 
 
 32 
 
 34 
 
 36 
 
 15 
 
 33,600 
 
 7-7 
 
 8-4 
 
 91 
 
 97 
 
 10-3 
 
 10-8 
 
 11-4 
 
 119 
 
 129 
 
 12-8 
 
 13-2 
 
 137 
 
 141 
 
 145 
 
 lo 
 
 35.840 
 
 7-8 
 
 8-5 
 
 9-2 
 
 9-8 
 
 10-4 
 
 119 
 
 11-5 
 
 129 
 
 12*5 
 
 130 
 
 13-5 
 
 139 
 
 149 
 
 147 
 
 17 
 
 38,080 
 
 7-9 
 
 8-7 
 
 9-4 
 
 10-0 
 
 10-6 
 
 11-2 
 
 117 
 
 12-2 
 
 127 
 
 13-2 
 
 13 7 
 
 141 
 
 1 4*5 
 
 149 
 
 18 
 
 40,320 
 
 8-0 
 
 8-8 
 
 95 
 
 107 
 
 10-8 
 
 119 
 
 119 
 
 12-4 
 
 129 
 
 13-4 
 
 139 
 
 143 
 
 147 
 
 15-1 
 
 19 
 
 42,560 
 
 81 
 
 8-9 
 
 96 
 
 103 
 
 10-9 
 
 1 1-5 
 
 12-2 
 
 129 
 
 13 1 
 
 139 
 
 141 
 
 14-5 
 
 159 
 
 15-4 
 
 29 
 
 44,800 
 
 
 90 
 
 9-7 
 
 104 
 
 no 
 
 119 
 
 12-5 
 
 127 
 
 13 2 
 
 13 8 
 
 14-2 
 
 147 
 
 15-1 
 
 15*6 
 
 22 
 
 49,280 
 
 
 9-2 
 
 lo-o 
 
 107 
 
 11-3 
 
 119 
 
 12-8 
 
 13*0 
 
 139 
 
 141 
 
 149 
 
 157 
 
 15*5 
 
 159 
 
 24 
 
 53,760 
 
 
 9-4 
 
 102 
 
 109 
 
 11-5 
 
 12-2 
 
 139 
 
 13-4 
 
 139 
 
 14*4 
 
 149 
 
 15-4 
 
 159 
 
 169 
 
 26 
 
 58,240 
 
 
 90 
 
 10 4 
 
 lit 
 
 11-8 
 
 12-4 
 
 13-3 
 
 139 
 
 142 
 
 147 
 
 15*2 
 
 157 
 
 16-2 
 
 167 
 
 28 
 
 62,720 
 
 
 9-8 
 
 10-6 
 
 11-4 
 
 129 
 
 127 
 
 13-5 
 
 139 
 
 144 
 
 159 
 
 15*5 
 
 169 
 
 16*5 
 
 179 
 
 Deflexion in inches. . 
 
 •25 
 
 •3 
 
 •35 
 
 •4 
 
 •45 
 
 •5 
 
 •55 
 
 •0 
 
 •6G 
 
 •7 
 
 •75 
 
 •8 
 
 •85 
 
 •9 
 
 1 
 
 Lengths in feet. 
 
 14 
 
 16 
 
 18 
 
 20 
 
 22 
 
 24 
 
 26 
 
 28 
 
 30 
 
 32 
 
 34 
 
 36 
 
 38 
 
 40 
 
 30 
 
 67,200 
 
 10-8 
 
 11-5 
 
 12-2 
 
 12-9 
 
 13-5 
 
 141 
 
 147 
 
 15*2 
 
 157 
 
 16-3 
 
 16-8 
 
 179 
 
 177 
 
 18-2 
 
 32 
 
 71,680 
 
 11*0 
 
 117 
 
 12-4 
 
 13-1 
 
 13-7 
 
 149 
 
 14*9 
 
 15-5 
 
 169 
 
 16-5 
 
 179 
 
 17-5 
 
 189 
 
 18 5 
 
 34 
 
 76,160 
 
 111 
 
 1 1-9 
 
 12-6 
 
 13-3 
 
 139 
 
 14-5 
 
 151 
 
 157 
 
 16-2 
 
 16*8 
 
 179 
 
 17-8 
 
 189 
 
 18-8 
 
 36 
 
 80,640 
 
 11-3 
 
 12-0 
 
 12-8 
 
 13-4 
 
 111 
 
 147 
 
 159 
 
 159 
 
 16-5 
 
 179 
 
 17-5 
 
 189 
 
 18-5 
 
 199 
 
 38 
 
 85,120 
 
 11-4 
 
 12-2 
 
 130 
 
 13 6 
 
 14 3 
 
 149 
 
 15 5 
 
 161 
 
 167 
 
 17-2 
 
 17-8 
 
 189 
 
 18-8 
 
 199 
 
 40 
 
 89,600 
 
 
 12-4 
 
 13-1 
 
 13-8 
 
 14-5 
 
 15-1 
 
 157 
 
 16-4 
 
 169 
 
 17'5 
 
 189 
 
 18-5 
 
 101 
 
 19-5 
 
 42 
 
 94,080 
 
 
 12'5 
 
 13-3 
 
 140 
 
 14-7 
 
 159 
 
 159 
 
 16 5 
 
 171 
 
 177 
 
 18-2 
 
 187 
 
 199 
 
 19-8 
 
 44 
 
 98,560 
 
 
 12-7 
 
 13*5 
 
 142 
 
 149 
 
 15*5 
 
 161 
 
 10-8 
 
 17-4 
 
 179 
 
 18'5 
 
 199 
 
 19-5 
 
 20*0 
 
 46 
 
 103,040 
 
 
 12-8 
 
 13 6 
 
 14*3 
 
 150 
 
 157 
 
 169 
 
 170 
 
 179 
 
 181 
 
 187 
 
 19-2 
 
 19-8 
 
 209 
 
 48 
 
 107,520 
 
 
 I3'0 
 
 137 
 
 14-5 
 
 152 
 
 159 
 
 16*5 
 
 17 1 
 
 177 
 
 189 
 
 18'8 
 
 19-4 
 
 20*0 
 
 20-5 
 
 50 
 
 112,000 
 
 
 
 13-8 
 
 14-6 
 
 159 
 
 169 
 
 16 6 
 
 17-3 
 
 179 
 
 18-5 
 
 199 
 
 199 
 
 20-1 
 
 207 
 
 52 
 
 116,480 
 
 
 
 14-0 
 
 147 
 
 15-5 
 
 16 2 
 
 16-8 
 
 17-5 
 
 18-1 
 
 187 
 
 19'2 
 
 198 
 
 20*3 
 
 21-0 
 
 54 
 
 120,960 
 
 
 
 14-1 
 
 14-9 
 
 15-7 
 
 169 
 
 179 
 
 179 
 
 182 
 
 18-8 
 
 19*4 
 
 199 
 
 20*5 
 
 21-1 
 
 56 
 
 125,440 
 
 
 
 14-3 
 
 150 
 
 15 8 
 
 16*5 
 
 17-1 
 
 178 
 
 18-4 
 
 199 
 
 199 
 
 207 
 
 20*7 
 
 219 
 
 58 
 
 129,920 
 
 
 
 14-4 
 
 15-1 
 
 159 
 
 16 6 
 
 179 
 
 17*9 
 
 18-5 
 
 192 
 
 197 
 
 209 
 
 20*9 
 
 21-4 
 
 60 
 
 134,400 
 
 
 
 14-5 
 
 15-3 
 
 160 
 
 167 
 
 17-4 
 
 18-1 
 
 187 
 
 199 
 
 199 
 
 20*5 
 
 241 
 
 219 
 
 Deflexion in inches. 
 
 •35 
 
 •4 
 
 ■45 
 
 •5 
 
 ■55 
 
 •6 
 
 |95 
 
 7 
 
 75 
 
 •8 
 
 •85 
 
 •9 
 
 95 
 
 19 
 
670 
 
 STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 Examples illustrative of the Table. — 1. To find the depth of a rectangular bar of cast-iron to support 
 a weight of 10 tons in the middle of its length, the deflexion not to exceed l-40th of an inch per foot in 
 length, and its length 20 feet, also let the depth be 6 times the breadth. 
 
 Opposite 6 times the weight and under 20 feet >n length is 15'3 inches, the depth, and l-6th ol 
 15'3 = 2'6 inches, the breadth. 
 
 2. To find the diameter for a cast-iron shaft or solid cylinder that will bear a given pressure, the 
 flexure in the middle not to exceed l-40th of an inch for each foot of its length, the distance of the bear- 
 ings being 20 feet, and the pressure on the middle equals 10 tons. 
 
 Constant multiplier T7 for round shafts, then 10 X TV = 17. And opposite 17 tons and under 20 
 feet is 1T2 inches for the diameter. 
 
 But half that flexure is quite enough for revolving shafts : hence 17 X 2 = 34 tons, and opposite 34 
 tons is 13'3 inches for the diameter. 
 
 The preceding tables of the strength of cast-iron bars are the data of recent experiments by Mr 
 Hodgkinson of Manchester, and extracted from his new edition of Tredgold on the strength of cast-iron. 
 This gentleman has also made extensive experiments for obtaining the strongest form of t 
 section for beams, the following of which is the strongest form yet obtained. J 
 
 The bottom flange B is as 6 to 1 of the top flange T, or contains 6 times its sectional area. 
 
 He also gives the following rule for ascertaining the ultimate strength of beams of cast- 
 iron of the preceding section and proportions. 
 
 Multiply the sectional area of the bottom flange in inches by the depth of the beam in 
 inches, and divide the product by the distance between the supports, also in inches, and 
 514 times the quotient will give the breaking weight in cwts. 
 
 Table of the Weight of Modulus of Elasticity of various Metals 
 
 Name of Metal. 
 
 Modulus of Elas- 
 ticity, in lbs. 
 
 Name of Metal. 
 
 Modulus of Elas- 
 ticity, in lbs. 
 
 Steel 
 
 29,000,000 
 
 24.920.000 
 
 18.400.000 
 
 13.680.000 
 
 Gun-metal 
 
 Brass 
 
 9.873.000 
 
 8.930.000 
 
 4.608.000 
 720,000 
 
 
 Tin 
 
 
 Lead 
 
 
 
 Note. — Modulus of elasticity, or measure by which the comparative stiffness of bodies may be ascer- 
 tained: thus, the modulus of elasticity for oak is 1714500, and for cast-iron 18400000, or 10'7 times 
 that of oak; therefore a piece of cast-iron is 107 times as stiff as a piece of oak of equal dimensions 
 and bearing. 
 
 A hard body is that which yields least to 
 any stroke or impressive force; and in uni- 
 form bodies the degree of yielding is always 
 proportioned to the weight of the modulus of 
 elasticity. 
 
 Resilience, or toughness of bodies, is strength 
 and flexibility combined ; hence any material 
 or body which bears the greatest load, and 
 bends the most at the time of fracture, is the 
 toughest. 
 
 Annexed i9 a Table of experiments on rect- 
 angular bars of malleable iron by Mr. Bar- 
 low, for the purpose of determining the point 
 of neutral axis, the centre of compression, 
 and the greatest deflexion to which railway 
 bars or lines of rail might be submitted 
 without causing permanent injury to the pro- 
 perties of the iron. 
 
 Note. — Distance between the bearings 33 
 inches ; breadth of bar 1 j inch ; depth 3 
 inches. 
 
 The neutral axis was found to be l-5th of 
 the depth from the top of the bar ; the centre 
 of compression §ds of that fifth above the 
 neutral axis ; and the rule for obtaining the 
 utmost degree of deflexion as follows : 
 
 Divide '22 by 4-5ths the depth of the bar 
 ,n inches, and the quotient is the utmost de- 
 flexion that can be suffered with safety on 
 bearing 33 inches apart. 
 
 To find the weight that railway bars will 
 support. — Observe, that whatever figure may 
 oe given to the transverse section, the head, 
 or top portion of the rail, is generally sup- 
 posed to occupy the 2-5ths of the whole section ; or, in the larger description, to have two inches sec 
 tion, and to be one inch deep, and that the lower web be the same depth as the head 
 
 Weight in 
 tons. 
 
 Deflexion 
 in inches. 
 
 Deflexion 
 per half 
 ton. 
 
 Remarks. 
 
 T25 
 
 ■500 
 
 TOO 
 
 T50 
 
 2-00 
 
 2-50 
 
 8-00 
 
 350 
 
 4-00 
 
 4-50 
 
 •50 
 
 TOO 
 
 T50 
 
 2-00 
 
 2- 50 
 300 
 
 3- 50 
 
 4- 00 
 4-50 
 
 •50 
 
 TOO 
 
 T50 
 
 2-00 
 
 2- 50 
 
 3- 00 
 3-50 
 
 7-50 
 
 •043 
 
 •059 
 
 •074 
 
 •083 
 
 •095 
 
 •101 
 
 •109 
 
 •120 
 
 T31 
 
 T48 
 
 •017 
 
 •037 
 
 •052 
 
 •061 
 
 •064 
 
 •078 
 
 •089 
 
 T02 
 
 T24 
 
 ■003 
 
 ■050 
 
 •060 
 
 •074 
 
 •093 
 
 • 110 ' 
 
 T49 
 
 015 
 
 009 
 
 012 
 
 006 
 
 008 
 
 Oil 
 
 Oil 
 
 017 
 
 015 
 
 009 
 
 003 
 
 014 
 
 011 
 
 013 
 
 022 
 
 020 
 
 010 
 
 014 
 
 019 
 
 017 
 
 Mean, ‘0103. 
 k) = 4F Neutral axis, 
 Y 1 : 4-9. 
 
 Elasticity preserved 
 at 4 j tons. 
 
 Mean, ‘0108. 
 w — 4R Neutral axis, 
 1 : 4-9. 
 
 Elasticity injured. 
 
 The depth of this bar 
 only 2 1 inches. 
 Mean, -0173. 
 
 Bent 8 inches. 
 
 w = 3. Neutral axis, 1 
 4 9. Elasticity pre- 
 served, 3 tons. 
 
STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 671 
 
 Resistance of the head or upper portion of the rail. — Rule. — Subtract, the thickness of the middle rib 
 from 2 inches, and multiply the remainder by 10. — Again, subtract an inch from the whole depth, 
 and multiply the remainder by 12; then divide the former product by the latter and the quotient 
 equals the resistance, in tons, due to the head, not including the continuation of the middle rib. 
 
 Resistance of the centre rib. — Rule. — Multiply the whole depth of the rail in inches by the whole 
 depth minus ^ an inch, and that product by 10 times the thickness of the rib; jd of the last product 
 equals the resistance, in tons, of the middle rib continued through the whole depth. 
 
 Resistance of lower web. — Rule. — Multiply the whole depth of the rail, minus 1 inch, by the breadth 
 of the bottom web, minus the thickness of the rib, and that product by 10. — Again: from the whole 
 depth of the rail subtract 1 inch, and to 12 times the square of the remainder add 6 times the remain- 
 der, and call this the first number. From this subtract twice the remainder, and add 1, and call this 
 the second number. Then say, as the first number is to the second, so is the product obtained in the 
 former part of the rule to the resistance of the lower web, not including the continuation of the mid- 
 dle rib. 
 
 Then, the sum of these three resistances multiplied by 4, and divided by the clear bearing length, 
 will be the weight, in tons, that the rail will sustain without injury. 
 
 Ex. 1. Let the depth of a rail be 5 inches, with a plain rib, whose thickness is -9 of an inch ; required 
 the greatest weight that it ought to be required to bear. 
 
 R . , fl , < (2 — -9). X 10 = 11 ) 11 no 
 Resistance of head j (5 _ x 12 = 54 \ 54 = °' 2 ' 
 
 44 X 5 X -9 X 10 67-5 , 4 X 67'7 , . , 
 
 Resistance of rib = — — ; and, 8*21 tons, the greatest weight; and 
 
 3 67*7 33 6 & ’ 
 
 •22 
 
 the deflexion with this weight — =-05 of an inch nearly. 
 5 4-5 
 
 Ex 2. Suppose a rail with bottom web, the depth of rail being 5 inches, the thickness of rib 6 of 
 an inch, breadth of section of lower web 1 '32, and weight 50 lbs.; required the greatest load. 
 
 Resistance of head j j j * jj> II 1 j j- ~= 0'26 tons. 
 
 t, • . . .,4$' X 5 X -6 X 10 
 
 Resistance of rib = 45'00 do 
 
 f (5 — 1) X '72 X 10 X 28-8 
 Lower web I 12 (5 — l) 2 -f- 24 = 210, or 1st number j 
 ( 216 — 7 = 209, or 2d number 
 
 Then 210 : 209 : : 28-8 : 27'94 = 27'94 
 
 And 
 
 73 2 X 4 
 33 
 
 = 8'75 tons, the greatest weight. 
 
 73-20 
 
 ON THE STRENGTH OF COLUMNS, OR POWER OF RESISTANCE TO COMPRESSIVE FORCE. 
 
 Ti jle of Practical Formulce by which to determine the Amount of Weight a Column of given Dimen- 
 sions will support in lbs. 
 
 For a rectangular column of cast-iron 
 
 For a rectangular column of malleable iron 
 
 For a rectangular column of oak 
 
 For a solid cylinder of cast-iron 
 
 For a solid cylinder of malleable iron 
 
 For a solid cylinder of oak 
 
 Vote. — AV = the weight the column will support in lbs. 
 b = the breadth in inches. 
 
 1 = the length in feet. 
 d = the diameter in inches. 
 
 15300 lb 3 
 
 ~ 4 b- + 18 l r 
 17800 lb 3 
 ~ 4 6 s + -16 A 
 3960 lb' 
 
 W — 4 6 2 + -5 P' 
 _ 9562 d‘ 
 
 ~4d 2 + -18 A 
 11!25 d' 
 
 ~ 4</ 2 + -16 f 2 ' 
 _ 2470 d* 
 
 4 d 2 -f- -5 P' 
 
 Ex. 1 . A rectangular column of oak, 6 inches on the side, and 12 feet in length, what weight will it 
 support ? 
 
 3960 X 12 X 6 3 
 4 X O 2 + -5 X J2 2 
 
 10264320 
 
 = 47520 lbs. 
 
 216 
 
672 
 
 STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 Ex. 2. What weight will a cast-iron cylinder support, whose diameter is 4 inches, and length 10 
 feet ? 
 
 95G2 X 5' 
 
 4 X 5 2 + -18 X 10' 2 
 
 5976250 
 
 118 
 
 = 50646 lbs. 
 
 Table to shovi the Weight or Pressure a Column of Cast-iron will sustain with safety. 
 
 Length or 
 height in 
 feet. 
 
 4 
 
 6 
 
 8 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 20 
 
 22 
 
 24 
 
 Diameter. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 Weight 
 in cwts. 
 
 In. 
 
 24 
 
 119 
 
 105 
 
 91 
 
 77 
 
 65 
 
 55 
 
 47 
 
 40 
 
 34 
 
 29 
 
 25 
 
 
 178 
 
 163 
 
 145 
 
 128 
 
 111 
 
 97 
 
 84 
 
 73 
 
 64 
 
 56 
 
 49 
 
 H 
 
 247 
 
 232 
 
 214 
 
 191 
 
 172 
 
 156 
 
 135 
 
 119 
 
 106 
 
 94 
 
 83 
 
 4 
 
 326 
 
 310 
 
 288 
 
 266 
 
 242 
 
 220 
 
 198 
 
 178 
 
 160 
 
 144 
 
 130 
 
 H 
 
 418 
 
 400 
 
 379 
 
 354 
 
 327 
 
 301 
 
 275 
 
 251 
 
 229 
 
 208 
 
 189 
 
 5 
 
 522 
 
 501 
 
 479 
 
 452 
 
 427 
 
 394 
 
 365 
 
 337 
 
 310 
 
 285 
 
 262 
 
 6 
 
 607 
 
 592 
 
 573 
 
 550 
 
 525 
 
 497 
 
 469 
 
 440 
 
 413 
 
 386 
 
 360 
 
 7 
 
 1032 
 
 1013 
 
 989 
 
 959 
 
 924 
 
 887 
 
 848 
 
 808 
 
 765 
 
 725 
 
 686 
 
 8 
 
 1333 
 
 1315 
 
 1289 
 
 1259 
 
 1224 
 
 1185 
 
 1142 
 
 1097 
 
 1052 
 
 1005 
 
 959 
 
 • 9 
 
 1716 
 
 1697 
 
 1672 
 
 1640 
 
 1603 
 
 1561 
 
 1515 
 
 1467 
 
 1416 
 
 1364 
 
 1311 
 
 10 
 
 2119 
 
 2100 
 
 2077 
 
 2045 
 
 2007 
 
 1964 
 
 1916 
 
 1865 
 
 1811 
 
 1755 
 
 1697 
 
 11 
 
 2570 
 
 2550 
 
 2520 
 
 2490 
 
 2450 
 
 2410 
 
 2358 
 
 2305 
 
 2248 
 
 2189 
 
 2127 
 
 12 
 
 3050 
 
 3040 
 
 3020 
 
 2970 
 
 2930 
 
 2900 
 
 2830 
 
 2780 
 
 2730 
 
 2670 
 
 2600 
 
 Relative Strength of Long columns of different materials, Cast-iron being 1000 : 
 
 Steel 
 
 Wrought-iron 
 Dantzic oak.. 
 Red deal 
 
 = 2518 
 = 1745 
 = 108-8 
 = 78-5 
 
 Elasticity of torsion, or resistance of bodies to being twisted . — The angle of flexure by torsion is as 
 the length and extensibility of the body directly and inversely as the diameter. Hence, the length of a 
 bar or shaft being given, the power, and the leverage the power acts with, being known, and also the 
 number of degrees of torsion that will not affect the action of the machine, to determine the diameter 
 in cast-iron with a given angle of flexure : 
 
 Rule. — Multiply the power in pounds by the length of the shaft in feet, and by the leverage in feet ; 
 divide the product by 55 times the number of degrees in the angle of torsion, and the fourth root of the 
 quotient equals the shaft’s diameter in inches. 
 
 Ex. Required the diameter of a series of shafts, 30 feet in length, and to transmit a power equal to 
 4000 lbs., acting at the circumference of a wheel of 2 feet radius, so that the twist of the shafts on the 
 application of the power may not exceed one degree. 
 
 4000 X 30 X 2 
 55 X 1 
 
 4 */4364 = 8T3 inches diameter. 
 
 Note. — The rule is the same for hollow shafts, only using 48 in place of 55, the thickness of metal 
 being l-5th the shaft’s diameter. 
 
 To determine the side of a square shaft to resist torsion with a given flexure : 
 
 Rule. — Multiply the power in pounds by the leverage it acts with in feet, and also by the length of 
 the shaft in feet; divide this product by 92-5 times the angle of flexure in degrees, and the square root 
 of the quotient equals the area of the shaft in inches. 
 
 Ex. Suppose the length of a shaft to be 12 feet, and to be driven by a power equal to 700 lbs., 
 acting at 1 foot from the centre of the shaft ; required the area of cross-section, so as it may not exceed 
 1 degree of flexure. 
 
 700 X 1 X 12 . , 
 
 — — — : — = \/90-8 = 9’oS inches. 
 
 9 2 ‘ o X 1 
 
 Relative Strength of Bodies to resist Torsion, Lead being 1. 
 
 Tin = 1-4 
 
 Copper = 4'3 
 
 Yellow brass = 4'6 
 
 Gun-metal . . = 5 0 
 
 Cast-iron = 9'0 
 
 Swedish iron 
 
 — 9-5 
 
 English do 
 
 — 10-1 
 
 Blistered steel 
 
 — 16-6 
 
 Shear do 
 
 — 17-0 
 
 Cast do 
 
 — 19-5 
 
STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 673 
 
 Strength of hletals when Pulled in the Direction of their Length. 
 
 Names of metals. 
 
 Specific 
 
 (Gravity. 
 
 Force 
 necessary 
 to tear 
 nsunder 1 
 sq. in. in 
 lbs. Avd. 
 
 Antimony, cast 
 
 4-500 
 
 1-060 
 
 Bismuth, cast 
 
 9-810 
 
 3-250 
 
 “ cast 
 
 9-926 
 
 3-008 
 
 Copper, cast, Barbary 
 
 8-182 
 
 22-570 
 
 “ “ Japan 
 
 8-726 
 
 20-27 
 
 
 
 61-228 
 
 Gold, cast 
 
 19-238 
 
 20-450 
 
 
 
 30-888 
 
 Iron, cast 
 
 
 “ gray, of Cruzot, 1st fusion. 
 
 
 30-162 
 
 “ “ “ 2d “ 
 
 
 30-6S0 
 
 “ Engli-di 
 
 
 52-000 
 
 “ “ soft 
 
 
 40-824 
 
 
 
 70-367 
 
 << a 
 
 
 50-981 
 
 U (( 
 
 
 42-666 
 
 “ “ soft 
 
 
 63-622 
 
 “ “ gray 
 
 
 37-680 
 
 “ German 
 
 7-807 
 
 68-295 
 
 Iron, -wrought 
 
 
 
 “ bar, coarse grained 
 
 
 20-460 
 
 “ “ medium fineness 
 
 
 34-081 
 
 “ “ fine-grained 
 
 O 
 
 49-982 
 
 “ “ of good quality 
 
 CO 
 
 55000 
 
 “ bar 
 
 o 
 
 61041 
 
 “ “ of best quality 
 
 o 
 
 66000 
 
 “ bar 
 
 o 
 
 80-000 
 
 u 
 
 G 
 
 80-333 
 
 u tc 
 
 £ 
 
 84-443 
 
 “ Germ, marked B. R 
 
 o 
 
 f-t 
 
 ,61-361 
 
 W “ “ “ 
 
 
 93069 
 
 “ “ common 
 
 
 69-133 
 
 “ “ marked L 
 
 
 69*538 
 
 Names of metals. 
 
 * 
 
 Specific 
 G ravity. 
 
 Ferce 
 neco-jsary 
 to tear 
 asunder 1 
 sq. in. in 
 lbs. Avd. 
 
 Iron, German, marked L 
 
 
 85-900 
 
 
 
 62-369 
 
 “ ditto 
 
 o 
 
 82-839 
 
 “ Oosement 
 
 CO 
 
 68-728 
 
 “ ditto 
 
 G 
 
 76-697 
 
 “ Spanish. 
 
 -2 
 
 81-901 
 
 “ Swedish 
 
 o 
 
 o 
 
 68-728 
 
 “ ditto 
 
 
 88-972 
 
 “ cable 
 
 
 54-513 
 
 
 o 
 
 73024 
 
 
 
 85-797 
 
 
 
 113-077 
 
 Lead, cast 
 
 11-479 
 
 0-885 
 
 
 2-547 
 
 
 1 1-282 
 
 2-581 
 
 
 11-348 
 
 3-146 
 
 “ milled 
 
 11-407 
 
 3-328 
 
 
 52-987 
 
 
 20-847 
 
 56-473 
 
 Silver, cast 
 
 11-091 
 
 40-902 
 
 
 38-257 
 
 
 7-780 
 
 120-000 
 
 “ razor-tempered 
 
 to 
 
 7*840 
 
 150-000 
 
 Tin, cast, Banca 
 
 7-217 
 
 
 
 7-295 
 
 5*322 
 
 “ “ ditto 
 
 
 u “ Malacca 
 
 6-126 
 
 3-211 
 
 
 7-1 9,9 
 
 Zinc, cast, Goslar 
 
 “ “ ditto 
 
 7-215 
 
 7-215 
 
 2*937 
 
 2*689 
 
 “ patent sheet 
 
 16*616 
 
 “ wire 
 
 
 22-551 
 
 Strength of Alloys when Pulled in the Direction of their Length. 
 
 Parts. Parts.] 
 
 Brass 
 
 
 i 
 
 
 45-882 
 
 Copper 
 
 10— Tin 
 
 i 
 
 
 32-093 
 
 “ 
 
 8 “ 
 
 i| 
 
 
 36-088 
 
 “ 
 
 6 “ 
 
 ii 
 
 
 44-071 
 
 “ 
 
 4 “ 
 
 i 
 
 
 35-739 
 
 “ 
 
 0 « 
 
 i 
 
 
 1-017 
 
 “ 
 
 1 “ 
 
 i 
 
 
 0-725 
 
 Gold 
 
 5 — Copper ... 
 
 i 
 
 
 50-000 
 
 “ 
 
 o — Silver 
 
 1 
 
 
 28-000 
 
 Lead, Scotch, 1 0 — Bismuth . . . 
 
 i 
 
 10-827 
 
 2-826 
 
 “ “ 
 
 2 “ 
 
 i 
 
 11-090 
 
 5-840 
 
 “ “ 
 
 i 
 
 i 
 
 10-931 
 
 7-319 
 
 Silver 
 
 . 5 — Copper.... 
 
 i 
 
 
 4S-500 
 
 “ 
 
 . 4— Tin 
 
 i 
 
 
 41*000 
 
 Tin, Banca.. 
 
 10 — Antimony. 
 
 i 
 
 7-359 
 
 11-181 
 
 “ “ 
 
 8 
 
 i 
 
 7-276 
 
 9-881 
 
 “ .. 
 
 6 
 
 i 
 
 7-228 
 
 12-632 
 
 “ “ 
 
 4 
 
 ii 
 
 7-192 
 
 13-480 
 
 
 2 “ 
 
 i 
 
 7-105 
 
 12-029 
 
 U U 
 
 i 
 
 i 
 
 7-060 
 
 3-184 
 
 it (( 
 
 10 — Bismuth ... 
 
 i 
 
 7-576 
 
 12-688 
 
 U it 
 
 4 
 
 ii 
 
 7 613 
 
 16-692 
 
 u u 
 
 2 “ 
 
 1 
 
 8-070 
 
 14-017 
 
 
 
 Parts. Paits. 
 
 
 
 Tin, 
 
 Banca... 
 
 1— Bismuth .. 
 
 i 
 
 8-146 
 
 12-020 
 
 “ 
 
 ... 
 
 1 
 
 2 
 
 8-580 
 
 10-013 
 
 “ 
 
 “ ... 
 
 1 
 
 4 
 
 9-009 
 
 7-875 
 
 “ 
 
 “ ... 
 
 1 
 
 10 
 
 9-439 
 
 3-871 
 
 “ 
 
 “ ... 
 
 10 — Zinc, In- 
 
 
 
 
 
 
 dian 
 
 1 
 
 7-288 
 
 12-914 
 
 “ 
 
 “ ... 
 
 2 “ 
 
 1 
 
 7-000 
 
 15-025 
 
 “ 
 
 “ 
 
 i “ .... 
 
 1 
 
 7-321 
 
 15-844 
 
 “ 
 
 “ ... 
 
 i “ .... 
 
 2 
 
 7-100 
 
 16023 
 
 “ 
 
 “ 
 
 i “ .... 
 
 10 
 
 7-130 
 
 5*671 
 
 U 
 
 
 4 — Antimony 
 
 1 
 
 
 11-323 
 
 “ 
 
 “ 
 
 3 
 
 2 
 
 
 3-184 
 
 “ 
 
 “ ... 
 
 1 
 
 i 
 
 7-000 
 
 1-450 
 
 Tin, 
 
 English 
 
 10 — Lead ..... 
 
 i 
 
 
 6-904 
 
 “ 
 
 “ 
 
 8 “ 
 
 i 
 
 
 7-922 
 
 “ 
 
 “ 
 
 6 « 
 
 i 
 
 
 7-997 
 
 “ 
 
 “ 
 
 4 “ 
 
 i 
 
 
 10-607 
 
 “ 
 
 “ 
 
 2 “ 
 
 i 
 
 
 7-470 
 
 “ 
 
 « 
 
 i “ 
 
 i 
 
 
 7-074 
 
 “ 
 
 
 8 Zinc, Goslar 
 
 i 
 
 
 10-607 
 
 “ 
 
 “ 
 
 4 >< 
 
 i 
 
 
 10-25S 
 
 “ 
 
 “ 
 
 2 “ “ 
 
 i 
 
 
 10964 
 
 “ 
 
 “ 
 
 i “ 
 
 i 
 
 
 9-024 
 
 
 
 
 
 
 1) 
 
 Vol. II— 4: 
 
674 
 
 STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 Strength of Woods when Pulled in the Direction of their Length. 
 
 Names of woods. 
 
 > 
 
 Specific 
 Gravity, a 
 
 Acacia 
 
 0-860 
 
 Alder 
 
 
 
 
 
 Ash 
 
 0-840 
 
 0-780 
 
 Ash 
 
 1 Ash 
 
 
 
 Ash, red, seasoned 
 
 0-812 
 
 0-685 
 
 “ white, seasoned 
 
 Bay '. 
 
 | Bay 
 
 
 
 0-720 
 
 Beech 
 
 Birch 
 
 0-640 
 
 0-990 
 
 0-400 
 
 0-540 
 
 Box 
 
 
 Cedar 
 
 Cedar 
 
 Chestnut, horse 
 
 0-610 
 
 0-610 
 
 0-877 
 
 
 “ do., 100 years in use... 
 
 Citron 
 
 Citron 
 
 
 
 
 Cypress 
 
 
 ! Damson 
 
 0-790 
 
 0-340 
 
 Deal, Norway spruce 
 
 “ ditto. 
 
 
 0-460 
 
 0-460 
 
 0-460 
 
 0-470 
 
 0-498 
 
 0-472 
 
 “ ditto. 
 
 “ ditto. 
 
 “ . English 
 
 “ Scotch, white 
 
 “ “ yellow 
 
 Elder I 
 
 Elm 
 
 
 Fir, American 
 
 0-416 
 
 “ Riga 
 
 “ Russian 
 
 0-459 
 
 “ ditto 
 
 “ ditto 
 
 
 “ Mem el, seasoned 
 
 
 “ weakest 
 
 
 “ strong red 
 
 
 “ strongest 
 
 
 “ ditto 
 
 
 Hawthorn 
 
 0-910 
 
 Hawthorn 
 
 Holly 
 
 0-760 
 
 Jujube 
 
 Jasmine 
 
 
 Jasmine 
 
 
 j Laburnum 
 
 0920 
 
 1-010 
 
 1-022 
 
 0'636 
 
 0-496 
 
 0-470 
 
 
 
 
 “ Scotch, seasoned 
 
 “ “ very dry 
 
 
 Force 
 ecessai-y 
 to tear 
 asunder 1 
 sq. in. in 
 lbs. Avd. 
 
 1G-000 
 
 14-186 
 
 7- 667 
 17-379 
 
 16- 700 
 19-600 
 
 17- 000 
 12-000 
 17-892 
 14-220 
 
 14- 572 
 10-220 
 22-200 
 
 17- 709 
 
 15- 000 
 
 15- 500 
 6-300 
 
 11- 400 
 
 4- 973 
 
 12 - 100 
 10-500 
 12-168 
 
 8- 176 
 12-782 
 
 5- 105 
 
 6- 895 
 14-000 
 
 18- 100 
 
 17- 600 
 1 2-400 
 
 12- 300 
 14-000 
 
 7- 000 
 4-290 
 
 8- 478 
 10-230 
 
 13- 489 
 
 8- 874 
 
 9- 072 
 10-008 
 10000 
 
 9-792 
 
 10- 876 
 8-280 
 
 11- 040 
 
 12- 420 
 
 13- 000 
 
 10- 700 
 9-200 
 
 16- 000 
 
 18- 915 
 12-020 
 
 11- 756 
 10-500 
 
 23- 400 
 
 24- 696 
 11093 
 
 7-888 
 7 020 
 
 Names of woods. 
 
 Specific 
 Gravity, a 
 
 Lemon 
 
 
 Lignum Vitte 
 
 1-220 
 
 Lime-tree 
 
 0-760 
 
 
 Mahogany 
 
 0-870 
 
 Mahogany 
 
 0-800 
 
 
 
 Maple, Norway 
 
 0-793 
 
 Mulberry 
 
 0-660 
 
 Mulberry 
 
 0-660 
 
 Mulberry 
 
 
 
 
 0-673 
 
 
 
 
 
 
 “ ditto, old 
 
 “ ditto 
 
 0-760 
 
 0-760 
 
 
 0-700 
 
 “ pile out of River Cam 
 
 0-610 
 
 0-670 
 
 
 
 
 “ ditto 
 
 1-068 
 
 
 
 0-660 
 
 
 0-660 
 
 
 0-771 
 
 
 0-828 
 
 
 1-164 
 
 
 
 
 
 
 “ Norway 
 
 0-590 
 
 
 0-660 
 
 “ St. Petersburg 
 
 0-550 
 
 
 0-490 
 
 
 
 
 
 
 
 
 
 0-360 
 
 
 
 
 
 
 
 
 
 0-700 
 
 
 0-690 
 
 
 
 
 
 0-530 
 
 “ Java, seasoned 
 
 “ Malabar, seasoned 
 
 0-697 
 
 0-688 
 
 
 0-619 
 
 Walnut 
 
 0590 
 
 
 0-390 
 
 
 Willow, dry 
 
 
 
 0790 
 
 
 Force 
 
 9- 457 
 
 11-800 
 23-500 
 
 20- 582 
 
 21- 800 
 
 16- 500 
 
 12-186 
 
 10- 584 
 
 17- 400 
 
 10-600 
 
 14-054 
 
 11- 501 
 
 11- 412 
 
 7- 704 
 
 8- 820 
 
 10- 224 
 
 14- 000 
 
 15- 000 
 19-800 
 
 4-500 
 
 7-700 
 
 16079 
 
 9-043 
 
 9-985 
 
 13- 659 
 
 16- 300 
 
 14- 000 
 
 12- 839 
 
 13- 602 
 
 14- 685 
 
 7- 818 
 
 12- 096 
 
 13- 176 
 
 12- 400 
 
 14- 300 
 
 13- 100 
 13-300 
 
 11- 351 
 
 12- 782 
 
 8- 308 
 11-501 
 
 7- 200 
 
 6- 641 
 
 4- 596 
 
 5- 878 
 
 8- 822 
 
 18- 600 
 
 13- 000 
 6'895 
 
 11- 247 
 8-200 
 
 14- 220 
 13-140 
 13-194 
 
 7- 800 
 14 000 
 
 12- 782 
 
 7- 628 
 
 8 - 000 
 
STRENGTH OF MATERIALS OF CONSTRUCTION. 
 
 675 
 
 Transverse strength of timber . — The following table contains the results of five different series of ex- 
 periments upon the strength and qualities of different sorts of timber. The experiments are detailed 
 at considerable length in Yol. Y. of the Professional Papers of the Royal Engineers. The names of the 
 experimenters are given at the top of the columns in which the mean results of their experiments are 
 contained. 
 
 W l 
 
 The transverse strength S is calculated from the common formula -, in which W is the weight in 
 
 4 a cr 
 
 pounds necessary to break a beam of l length, a breadth, and d depth, and supported at the ends ; oi 
 S may be taken as the resistance of a rod an inch square. 
 
 Table of the Transverse Strength of Timber. 
 
 Names of woods. 
 
 OBSERVERS. 
 
 Mean. 
 
 LT. NELSON, j 
 
 CAPT. YOUNG j 
 
 MR. MOORE. 
 
 MR. BARLOW. 
 
 LT. DENISON. 
 
 sp. gr. 
 
 S. 
 
 sp. gr. 
 
 s. 
 
 sp. gr. 
 
 S. 
 
 sp. gr. 
 
 S. 
 
 sp. gr. 
 
 S. 
 
 sp. gr 
 
 S. 
 
 African Oak 
 
 885 
 
 2484 
 
 
 
 962 
 
 2522 
 
 982 
 
 2493 
 
 1024 
 
 2595 
 
 988 
 
 2523 
 
 Ash, English 
 
 
 
 
 
 
 
 700 
 
 2026 
 
 
 
 700 
 
 2026 
 
 kk American 
 
 oil 
 
 1550 
 
 
 
 
 
 
 
 042 
 
 2041 
 
 626 
 
 1795 
 
 u u Swamp 
 
 
 
 
 
 
 
 
 
 925 
 
 1165 
 
 925 
 
 1165 
 
 u “ Black 
 
 
 
 
 
 
 
 
 
 533 
 
 861 
 
 533 
 
 801 
 
 Beech, English 
 
 
 
 
 
 
 
 090 
 
 1550 
 
 
 
 696 
 
 1556 
 
 American White. 
 
 
 
 
 
 
 
 
 
 7ii 
 
 ioso 
 
 711 
 
 1380 
 
 “ “ Red... 
 
 778 
 
 1720 
 
 
 
 
 
 
 
 772 
 
 1758 
 
 775 
 
 1739 
 
 Birch, Common 
 
 
 
 
 
 
 
 711 
 
 1928 
 
 
 
 711 
 
 1928 
 
 “ American Black. . 
 
 6 82 
 
 i848 
 
 
 
 
 
 649 
 
 1810 
 
 679 
 
 2525 
 
 670 
 
 2061 
 
 u “ Yellow. 
 
 
 
 
 
 
 
 
 
 750 
 
 1335 
 
 756 
 
 1335 
 
 Cedar, Bermuda 
 
 748 
 
 1395 
 
 
 H'ji 
 
 
 
 
 
 
 
 748 
 
 1443 
 
 Gaudaloupe 
 
 75(3 
 
 2044 
 
 
 
 
 
 
 
 
 
 756 
 
 2044 
 
 u American White. 
 
 
 
 
 
 
 
 
 
 3o4 
 
 700 
 
 354 
 
 700 
 
 u of Lebanon 
 
 
 
 
 
 
 
 
 
 330 
 
 1493 
 
 330 
 
 1493 
 
 
 
 
 
 
 
 
 
 1013 
 
 605 
 
 551 
 
 579 
 
 782 
 
 u Canada Rock 
 
 700 
 
 1809 
 
 
 
 
 
 
 
 751 
 
 2072 
 
 725 
 
 1970 
 
 Hickory, American 
 
 871 
 
 1672 
 
 
 2447 
 
 786 
 
 2PJ2 
 
 
 
 83« 
 
 2205 
 
 831 
 
 2129 
 
 “ “ Bitter Nut 
 
 
 
 
 
 
 
 
 
 871 
 
 1465 
 
 871 
 
 1465 
 
 Oak, English 
 
 834 
 
 1029 
 
 
 
 810 
 
 ioio 
 
 934 
 
 1672 
 
 733 
 
 1 550 
 
 829 
 
 1694 
 
 *• American White . . 
 
 645 
 
 1699 
 
 
 
 830 
 
 1699 
 
 872 
 
 1766 
 
 772 
 
 1809 
 
 779 
 
 1743 
 
 “ “ Red 
 
 940 
 
 1709 
 
 
 
 
 
 
 
 964 
 
 1005 
 
 952 
 
 1687 
 
 u li Live 
 
 1100 
 
 1862 
 
 
 
 
 
 
 
 
 
 1160 
 
 1862 
 
 u Adriatic 
 
 
 
 
 
 7is 
 
 i 509 
 
 993 
 
 1383 
 
 
 
 855 
 
 1471 
 
 “ Dantzic 
 
 
 
 
 
 684 
 
 1579 
 
 756 
 
 1457 
 
 
 
 720 
 
 1518 
 
 u Italian 
 
 
 
 
 
 790 
 
 1688 
 
 
 
 
 
 796 
 
 1088 
 
 “ Lorraine 
 
 
 
 
 
 790 
 
 1483 
 
 
 
 
 
 796 
 
 1483 
 
 u Memel 
 
 
 
 
 
 727 
 
 1005 
 
 
 
 
 
 727 
 
 1605 
 
 Pine, American White.. 
 
 453 
 
 1456 
 
 iio 
 
 i()73 
 
 
 
 
 
 432 
 
 1160 
 
 432 
 
 1229 
 
 “ “ Red .... 
 
 621 
 
 1944 
 
 
 1799 
 
 521 
 
 P289 
 
 657 
 
 i:iii 
 
 500 
 
 1261 
 
 576 
 
 1527 
 
 “ “ Yellow . 
 
 
 
 
 
 516 
 
 1188 
 
 553 
 
 1102 
 
 450 
 
 1266 
 
 508 
 
 1185 
 
 “ “ Pitch . . . 
 
 
 
 
 — 
 
 
 
 000 
 
 1632 
 
 820 
 
 1822 
 
 740 
 
 1727 
 
 u Virginia 
 
 
 
 
 
 590 
 
 1450 
 
 
 
 
 
 590 
 
 1456 
 
 u Archangel 
 
 
 
 
 
 551 
 
 1370 
 
 
 
 
 
 551 
 
 1370 
 
 “ Dantzic 
 
 
 
 
 
 049 
 
 I486 
 
 
 
 
 
 649 
 
 1420 
 
 u Memel 
 
 
 
 
 
 001 
 
 1348 
 
 
 
 
 
 601 
 
 1348 
 
 u Prussian 
 
 
 
 
 
 590 
 
 1445 
 
 
 
 
 
 590 
 
 14-15 
 
 “ Riga 
 
 
 
 
 
 562 
 
 1687 
 
 740 
 
 i()79 
 
 
 
 054 
 
 1383 
 
 Spruce 
 
 
 
 
 
 503 
 
 1346 
 
 
 
 
 
 503 
 
 1346 
 
 “ American 
 
 
 
 
 
 
 
 
 
 772 
 
 1036 
 
 772 
 
 1036 
 
 Mar-Forest Fir 
 
 
 
 
 
 
 
 698 
 
 1232 
 
 
 
 698 
 
 1232 
 
 Norway Spar 
 
 
 
 
 
 
 
 577 
 
 1474 
 
 
 
 577 
 
 1474 
 
 Deal, Christiana 
 
 
 
 
 
 
 
 G89 
 
 1502 
 
 
 
 089 
 
 1502 
 
 Canada Balsam 
 
 
 
 
 
 
 
 
 
 548 
 
 112 ;) 
 
 548 
 
 1123 
 
 Hemlock 
 
 
 
 
 
 
 
 
 
 911 
 
 1142 
 
 911 
 
 1142 
 
 
 
 
 
 
 
 1958 
 
 542 
 
 995 
 
 408 
 
 1 052 
 
 
 1335 
 
 u Amer. or Tamarak 
 
 
 
 
 
 
 
 
 433 
 
 911 
 
 433 
 
 911 
 
 Licmum-ViLe 
 
 1082 
 
 2 oi:i 
 
 
 
 
 
 
 
 
 
 1082 
 
 2013 
 
 Mahogany, Nassau 
 
 812 
 
 1752 
 
 
 iyiH 
 
 525 
 
 1503 
 
 
 
 
 
 068 
 
 1719 
 
 Mangrove, Bermuda Bl'k 
 
 1188 
 
 1699 
 
 
 
 
 
 
 
 
 
 1188 
 
 1699 
 
 u “ White 
 
 951 
 
 1985 
 
 
 
 
 
 
 
 
 
 951 
 
 1985 
 
 Teak 
 
 719 
 
 1898 
 
 
 
 723 
 
 1964 
 
 745 
 
 2462 
 
 
 
 729 
 
 2108 
 
 Poon 
 
 
 
 
 
 708 
 
 1687 
 
 579 
 
 2221 
 
 
 
 673 
 
 1954 
 
 
 
 
 
 
 
 
 710 
 
 1867 
 
 
 
 
 
 Sneeze wood 
 
 1006 
 
 3305 
 
 
 
 
 
 
 
 1060 
 
 3305 
 
 Yellow-wood 
 
 920 
 
 2103 
 
 
 
 
 
 
 
 
 
 926 
 
 2103 
 
 Greenheart 
 
 
 
 970 
 
 8471 
 
 
 
 1000 
 
 2759 
 
 
 
 985 
 
 2615 
 
 Wallaba 
 
 
 
 1147 
 
 1643 
 
 
 
 
 
 
 
 1147 
 
 1043 
 
 Bullet-tree 
 
 
 
 1075 
 
 2733 
 
 
 
 1029 
 
 2651 
 
 
 
 1052 
 
 2092 
 
 Kakarally 
 
 
 
 1223 
 
 2379 
 
 
 
 
 
 
 
 1223 
 
 2379 
 
 Crab-wood 
 
 
 
 648 
 
 1875 
 
 
 
 
 
 
 
 648 
 
 1875 
 
 Locust 
 
 
 
 
 
 
 
 954 
 
 3430 
 
 
 
 954 
 
 3430 
 
 Cabacally 
 
 
 
 
 
 
 
 900 
 
 2518 
 
 
 
 900 
 
 2518 
 
 Iron-wood 
 
 
 
 
 
 
 — 
 
 — 
 
 
 879 
 
 1800 
 
 879 
 
 1800 
 
 Sott Maple 
 
 
 
 
 
 
 .... 
 
 .... 
 
 
 075 
 
 1094 
 
 675 
 
 1694 
 
 Remarks. 
 
 i Sr- e- 
 
 f when dry. 
 
 S. Africa. 
 W. Indies. 
 
676 
 
 SUGAR-MILL, HORIZONTAL. 
 
 SUGAR-MILL, HORIZONTAL. By M. Nillus, of Havre. The figures furnish a good example ol 
 file form of machine used for crushing sugar-canes, as constructed by an eminent French engineer, who 
 has devoted his attention, in an especial manner, to the improvement of the apparatus used in the colo- 
 nies for the manufacture of sugar. It differs but slightly from the form usually adopted by English 
 makers. Many improvements have been recently proposed, but we have preferred giving engravings 
 of the more simple and compact form which is still mostly in use. 
 
 The conformation of the sugar-cane does not render it necessary that, for the extraction of its juice, 
 the cells which contain it should be previously broken, as is the case with sugar obtained from other 
 sources; simple pressure, properly applied, is all that is required for its expulsion. For this purpose 
 the canes are squeezed by being passed successively between rollers disposed somewhat like those of 
 a rolling-mill. In the older form of machines employed for the extraction of the juice, the rollers are 
 placed vertically, and it is only within the last few years that this arrangement has been supersedeo 
 by the sugar-mill with horizontal cylinders, which is not only cheaper in construction and more easily 
 fixed, but by its use the process of feeding is performed with much less labor, and at the same time 
 more efficiently. 
 
 Fig. 33C5 represents a front elevation of the entire mill, showing the form of the framing, and the 
 general disposition of the cylinders or rollers, and of the feeding-board, returner, and delivering-board. 
 
 Fig. 336(3 is an end view of the same, showing the geering by which the rollers are driven. 
 
 33 ( 36 . 
 
 Fig. 3367 is a half-sectional plan taken on the line v — w, in Fig. 3365. 
 
 Fig. 3368 is a similar half-section taken on the line x — y. 
 
 Fig. 3369 is a vertical transverse section, through the centre of the mill, exhibiting the form of section 
 of the framing or standards, and the internal construction of the top-roller, with its gudgeon and bear- 
 'UgS; 
 
 Fig. 3370 is a longitudinal section of the entire mill, in which the arrangement and dimensions of the 
 rollers and their gudgeons, and the disposition of the feeding-board, returner, and delivering-board, are 
 most distinctly represented. 
 
 Fig. 3371 is a longitudinal section of one of the lower or feeding and delivering rollers, and of one ot 
 the driving pinions. 
 
 Fig. 3372 a front elevation of the three driving pinions, corresponding in position with their respec- 
 tive rollers, as shown in Fig. 3370. 
 
 Fig. 3373 a detached view of one of the stay-bolts for strengthening the standards. 
 
 Fig. 3374 is a section of part of the feeding-board, through the socket of one of its supporting columns. 
 
 Fig. 3375 is a section of that part of the standard through which passes the screw for adjusting the 
 Searings of the feeding and delivering rollers ; and Fig. 3376 shows a face view of one of these bearing; 
 themselves. 
 
SUGAR MILL, HORIZONTAL. 
 
 677 
 
 General description . — The crushing-rollers consist of three strong cast-iron cylinders A B C, mounted 
 between the two massive lieadstocks or standards D D, and so disposed that the periphery of the upper 
 roller A is nearly in contact with those of both the others. The rollers are made from 2^ 1° 3 inches 
 thick, and to give additional strength, are ribbed in the centre. They are traversed by the strong mal- 
 leable-iron gudgeons a b c, fixed into their respective rollers by keys, in the usual manner, and carrying 
 at one extremity the geering by which the rollers are moved. The gudgeon of the upper roller A is 
 made of considerably greater strength than those of the others, as it has to sustain simultaneously the 
 strain of both. The feeding and delivering rollers B and C have small flanges at their ends, between 
 which the top-roller is placed, as shown in Fig. 3369 ; these flanges are for the purpose of preventing 
 the pressed canes from working into the mill-bed. Some makers still continue the practice, once uni- 
 versally adopted, of fluting the top-roller, in order the better to seize the canes, but it is now very gene- 
 rally abandoned, as it is found that after working some time, the surface of the rollers becomes suffi- 
 ciently rough to bite the canes effectively; and the fluted rollers have this disadvantage, that the grooves 
 carry round with them a considerable portion of the expressed juice, which is speedily absorbed by the 
 spongy canes, besides causing considerable waste by breaking the canes themselves. 
 
 The standards D D are securely fixed to the strong cast-iron sole-plate E, which, besides performing 
 this function, is constructed of such a form as to serve as a receptacle for the collection of the expressed 
 juice. For this purpose that part of the sole-plate marked F, which lies between the two standards, is 
 made to slope downwards from all sides, thus forming a species of trough or cistern, the bottom of 
 which communicates with the gutter e, also cast of a piece with the sole-plate, and through which the 
 juice runs off into the proper receptacles. The whole mill rests upon, and is bolted firmly to its foun- 
 dation G, which, in the example before us, consists of two strong beams of timber, but more generally a 
 stone foundation is preferred. The bolts/// which serve this purpose, pass through foundation, sole- 
 plate, and standards, so that the whole are at once bound together. 
 
 The standards D D are formed with indentations for the purpose of receiving the bearings H H of the 
 feeding and delivering rollers. These bearings consist of a single brass bush for each journal, and their 
 form, as well as the mode of their adjustment, is shown detached from the machine in Figs. 3375 and 
 3376. To regulate the distance of the rollers from each other, and to compensate for the wear and tear 
 of the bearings, these latter are so formed as to be capable of being moved to a greater or less distance 
 from the centre of the mill, and for this last purpose the bearings are made of considerable thickness at 
 the points opposite to which the strain is applied. A projecting tongue on the under side of the brass 
 fits into a corresponding groove in the standard, by which means the bearing is guided laterally, and 
 its motion is circumscribed to the required limits by a small projection d, cast upon the standard. A 
 small gutter g, which is indicated by the dotted lines in the general elevation, is also cast upon the 
 standard round the sole of the bearing, by which the oil applied for its lubrication is prevented from fall- 
 ing into the mill-bed, and is carried round to the outside of the mill. A strong screw h passes through 
 the end of the standard opposite to the centre of each bearing, and works into a nut i sunk into it for 
 the purpose of adjusting the lower rollers. 
 
 The cheeks 1 1 of the standards through which the screws h h pass, are united to, and consolidated 
 with, the main body of the lieadstocks, by the strong bolts K K, fixed to the latter by cotters, and se 
 cured externally by nuts, after traversing the upper extremities of the cheeks II and the cast-iron fer 
 ules k k, which serve to fill up the intermediate space. See Fig. 3373. 
 
 The axis a of the upper roller revolves in the brass bearings L L, which consist of double brass bushes 
 fitted into the upper portion of the standards D D. They are surmounted by the massive caps or covers 
 >1 M, which are retained in their places by strong bolts N N, traversing the whole height of the stand- 
 ards, and secured under the sole-plate by cotters. These bolts serve likewise, by means of the nuts n n, 
 to regulate the pressure to which it may be thought expedient to subject the upper roller. 
 
 Between the lower rollers is placed a cast-iron plate 0. called the returner ; it is usually made con- 
 cave upon its upper surface, and is serrated at the edges to admit of the free flowing of the liquor to 
 the mill-bed. At each extremity it is furnished with projecting tails, which pass through slots in the 
 
678 
 
 SUGAR MILL, HORIZONTAL. 
 
 standards, and are supported by the slips of wood P P, which may be made of greater cr less thickness 
 according as it is found necessary to elevate or depress the returner. The use of the returner is to 
 direct the canes which have been crushed between the top-roller A and the feeding-roller C, so that thev 
 may be again subjected to pressure between the former and the delivering-roller B. 
 
 The three rollers ABO are simultaneously set in motion by the strong spur-pinions Q R S, fixed by 
 keys upon the extremities of their respective gudgeons and geering together, as shown in Fig. 3372. 
 The pinion of the upper roller, which communicates motion to the others, is itself set in motion by the 
 driving-shaft, through the intervention of a clutch or coupling-box, fitting into the teeth q q q, which are 
 cast upon it. To provide for the varying resistance arising from irregular feeding, or from the acciden- 
 tal crossing of the canes, by which accidents the engine is liable to be brought up so suddenly as to en- 
 danger the breaking of the fly-wheel shaft, it is necessary to make all these connections of unusual size 
 and weight. The best surface speed for the rollers is 3'4 or 3'6 feet per minute. 
 
 The feed-board P consists of a flat plate of cast-iron, strengthened by feathers on its under surface. 
 It is set at a considerable inclination, and furnished with sheet-iron sides, and its purpose is to convey 
 the canes regularly and equably from the hands of the feeder to the mill. The feed-board rests upon 
 two cast-iron columns 1 1, fixed by cotters at their lower extremities to the edge of the mill-bed. Fig. 
 3374 shows the mode of their attachment to the feed-board. 
 
 On several sugar estates a continuous system of feeding has been recently adopted, and might, we 
 think, be generally employed with advantage. This consists of an endless web of cloth, carried by two 
 parallel rollers, on which the canes are laid. One of the rollers receives motion from the mill itself, and 
 consequently the cloth progresses regularly, carrying the canes with it, and delivering them to be 
 crushed between the feeding and upper rollers. By this means the canes are all presented to the action 
 of the rollers in a longitudinal direction, and in the most equable and regular manner ; whereas, when 
 spread on the hopper by the hands of the negroes, the quantity admitted is sometimes too large and 
 sometimes too small, which has the disadvantage, in the one case, of permitting a portion of the canes 
 to pass between the rollers without receiving the due amount of pressure, and in the other of unneces- 
 sarily straining the mill. 
 
 The delivering-board U, by which the crushed canes are withdrawn from the mill after the juice has 
 been expressed, consists, like the feed-board, of a cast-iron table, set at a great angle, and fitted close to 
 the delivering-roller B, so as to detach any small portions of the canes that may adhere to it, and might 
 otherwise mix with the liquor. It is made so as to turn upon pivots at the top of the small columns u it 
 which support it. 
 
 Action of the machine . — The action of the sugar-mill is so obvious as scarcely to require to be spe- 
 cially noticed. The sugar-canes, having been previously cut into short lengths of about three feet, are 
 brought to the mill tied up in small bundles; there the feeder unites them, throws them on the feed 
 board T, and spreads them so that they may cross each other as little as possible. They are drawn in 
 between the feeding and top rollers A and C, where they are split and slightly pressed ; the liquor 
 flows down and is received into the mill-bed F, while the returner O guides the canes between the top 
 and delivering rollers A and B, where they receive the final pressure, and sliding down the delivering- 
 board U, are turned out on the floor of the mill, while the liquor runs back and falls into the mill-bed. 
 
 When circumstances will admit of it, it is desirable that the mill should be situated at such an eleva- 
 tion above the rest of the sugar apparatus as to render it unnecessary to raise the juice which flows 
 through the gutter e by pumping, as the contact of the air occasioned by the agitation of the liquor in 
 the pump-barrels tends to throw it into a state of fermentation. In very many cases, however, a pump 
 is attached to the sugar-mill, and is worked by suitable geering affixed to the gudgeon a of the upper 
 roller, wliich in our figures is shown of sufficient length to effect this purpose if required. 
 
 Literal References. , 
 
 A, the upper roller or cylinder. 
 
 «, the gudgeon or shaft of the upper roller, upon which it is fixed by keys. 
 
 B 0, the delivering and feeding rollers. 
 
 b c, their respective gudgeons. 
 
 D D, the standards or headstocks of the mill. 
 
 d d, small projections thereon for guiding the bearings of the rollers B and C. 
 
 E, the sole-plate, to which the standards D D are fitted, and which is also formed intc 
 
 F, the mill-bed, into which the expressed liquor flows. 
 
 e, the gutter for withdrawing the liquor from the mill-bed. 
 
 fff 6 )e holding-down bolts of the mill. 
 
 G G, strong beams, forming the foundation of the mill. 
 
 g g , gutters for withdrawing the superfluous oil from the bearings of the rollers B and C. 
 
 H H, brass bushes, forming the bearings of the rollers B and 0. 
 
 hh, regulating screws for the adjustment of the rollers B and C 
 
 % i, their nuts, sunk into the framing. 
 
 1 1, the cheeks of the framing, traversed by the screws li h. 
 
 K K, cotter-bolts, for strengthening the cheeks 1 1. 
 
 k k, cast-iron ferules on tiie bolts K K. 
 
 L L, the brass bearings of the top-roller. 
 
 M M, the plummer-block covers of the top-roller. 
 
 N N, the plummer-block cover bolts, which also regulate the pressure upon the top-roller by meara 
 jt the nuts n n. 
 
 O, the returner, fixed between the lower rollers, and serrated at each edge. 
 
 P P small slips of wood for supporting the returner. 
 
SUGAR BOILERS. 
 
 6 <9 
 
 Q, a stroDg spur-pinion on the gudgeon of the top-roller. On its face are also cast the projections 
 q q q, engaging with similar projections on the coupling-box of the driving-shaft. 
 
 RS, spur-pinions on the gudgeons of the lower rollers, geering with the pinion Q. 
 
 T, the feed-board. 
 
 1 1, small columns for supporting the feed-board. 
 
 U, the delivering-board, fitted with hinge-joints, to admit of its turning upon 
 u u, the small columns upon which it is supported. 
 
 3377. 
 
 Fig. 3377 represents a five-roller sugar-mill built by Nellius in France for the French colonies. 
 
 The mills used for grinding the cane are generally placed ten to twelve feet from the ground, in ordei 
 !o give sufficient fall for the juice to flow into the juice-boxes, and from them into the kettles. 
 
 3378. 
 
 The thickness of the shell of the rollers in those mills constructed by Leeds & Co., New Orleans 
 represented in Fig. 3378, varies from 2^ to 3 inches, according to size ; the depth of the eye of the 
 roller is 12 inches in all these mills. The shafts are of wrought-iron. The journals vary in size 
 from 7J to 8J inches in diameter. The boxes in which the journals revolve are of brass, lined with 
 “ Babbitt’s metal.” The return plats, about which there is a great difference of opinion respecting their 
 proper position, are placed from one to two inches below the top-roller. The cane-carrier is from fifty 
 to ninety feet in length, according to the height at which the mill is placed. 
 
 SUGAR BOILERS, Reed’s improved. The art of making sugar consists in separating the crystal- 
 lizable sugar from the liquor of the cane. This liquor often contains more than 70 per cent, of its 
 weight of sugar, and, in some instances, this amount has been extracted from the cane. Sugar is also 
 obtained from the beet, the maple, the melon, the carrot, the turnip, the green Indian corn plant, and 
 from many other substances. Extensive manufactories of beet sugar are now in operation on the con- 
 tinent of Europe, and in our forests vast quantities of maple sugar are annually manufactured. 
 
 Fig. 3379 is a view and description of parts of Mr. Knight Reed’s patent Flue Boiling Sugar Pans, to 
 whom was awarded a silver medal, by the American Institute, at the late Fair of October, 1850. 
 ABC, boilers. D E, clarifiers. F G H 1 1, flues. J K L M N", stopcocks for drawing off syrup. 0, stop- 
 ;ock for drawing off syrup from striking-teache. P, damper between striking-teache and second boiler. 
 R. damper, closing flues to striking-teache. S, door for draft. 7’, damper for shutting oft’ fire from flues 
 So striking-teache. U J stop-cock for drawing off washings. V, damper for shutting off the tire from 
 
580 
 
 SUGAR BOILERS. 
 
 going directly under the clarifiers, sending the draught through the teache and all the boilers. W W 
 dampers for shutting off draught from clarifiers D E. XXX, feeding-doors to the boilers. Y Y, feediug 
 doors to clarifiers. Z Z Z, doors for drawing the ashes from under the boilers. 
 
 The sugar-cane is twice subjected to the action of the mills, or is passed through two sets of rollers 
 of which the second pair are adjusted more closely together than the first. By this process, the sugar- 
 cane comes out from the rollers nearly dry, but some juice is still retained by the capillary forces ol 
 the plant, and cannot be entirely separated from it by any degree of pressure. The liquor thus pro- 
 duced soon undergoes fermentation if left to itself, and by very slight causes is changed into substances 
 of a nature entirely different from the pure solution of sugar, of which it at first consisted. Among 
 these substances are mucilage, lactic acid, alcohol, and carbonic acid. To prevent this change by fer- 
 mentation, the liquor, as soon as possible after it is expressed from the cane, is exposed to a high heat. 
 This checks its tendency to ferment. 
 
 As it comes from the mill, the juice is passed through a sieve or coarse cloth, to separate the coarse 
 6olid feculencies. It then flows from the mill-bed into channels through which it is conducted to re- 
 ceivers. These are generally two in number, placed in a situation as cool as possible, to diminish the 
 tendency of the liquor to ferment. They are also usually on a higher level than the boiling-house. 
 
 The crushed cane-stalks are carried from the mill to the trash-house, which, on large plantations, is a 
 building about one hundred feet long, eighteen feet wide, and fourteen feet high. In these the cane- 
 trash is carefully spread out, and means taken to render it perfectly dry. When dry it is employed 
 as fuel. 
 
 When the receiver, is filled with cane-liquor, a valve is opened, and the liquor flows out through a 
 channel lined with sheet-lead, into the clarifiers D and E, Fig. 3379. In the ordinary method, a fire is 
 lighted under these clarifiers, and lime is stirred into the cane-juice. The liquor soon becomes heated, 
 and the temperature gradually rises till the thermometer stands at about 210°. As the heat increases, 
 minute bubbles of air make their appearance, and a greenish-gray scum forms upon the surface of the 
 liquor. The temperature is not allowed to rise to the boiling point, as the motion thus produced in the 
 liquor would break the scum at the top, and mingle it again with the fluid by carrying down the fecu- 
 lencies which had risen to the top. In about forty minutes, the scum attains a thickness which causes 
 it to “ crack,” or to divide into white froth, as watery vapor rises up and forces its way through. Wheu 
 this is observed, the liquor is skimmed for about ten or twelve minutes, after which, if circumstances 
 will admit of the delay, the fire is damped, and the cane-liquor is allowed to remain undisturbed in the 
 <Tu ifiers for twenty or thirty minutes, or even longer, during which period there ensues a more com 
 
SUGAR BOILERS. 
 
 681 
 
 plete separation and rising of the impurities. This process is called clarifying, because in this way 
 the greater part of the feculencies is removed. 
 
 From the clarifiers the liquor is drawn off by stop-cocks M and N, (in Reed’s process ; various methods 
 are employed in other processes.) These stop-cocks are placed at such a distance from the bottom 
 that about one-twentieth of the liquid will remain in the boiler. In some cases the boiling-house is fur- 
 nished with only one clarifier ; in general, however, two or three, and in some large establishments 
 four are employed. The boiling-house of an estate in Jamaica, which produces 400 hogsheads of sugar 
 annually, is provided with three clarifiers, each of 440 gallons capacity, one grand evaporator of equal 
 magnitude, one of 300 gallons, another of 180 gallons, and another of 90 gallons, wine measure. 
 
 From the clarifiers the liquor passes into the first evaporator C, which, in Reed’s arrangement, holds 
 about 400 gallons. Flere the juice is allowed to boil. This boiling separates a kind of feculencies 
 which could not be separated by gentle heat, and which, therefore, were not removed in the clarifiers. 
 The scum, as it rises, is carefully removed by scummers. When, in this way, the cane-liquor is im- 
 proved in quality, thickened to a syrup, and reduced about two-thirds in quantity, it is then drawn off 
 into the second and smaller evaporator B. This evaporator holds about 200 gallons. New liquor may 
 now be admitted from the clarifiers into C. The syrup from C. is concentrated still further in B, and 
 then drawn off into the last evaporator A. This evaporator is technically called the tcache. In this 
 the syrup is concentrated to the requisite degree for crystallizing. This is called the striking-point, 
 and the concentrated syrup the strike , while striking is an operation performed in a set of wooden ves- 
 sels or wooden vats, not represented in the figure. These are made of cypress planks, and are very 
 shallow, measuring from four to five feet in width, by twelve to fourteen inches in depth. Not less 
 than six of these are used with one set of kettles, and, in general, a sugar-house contains eight or ten, 
 or even a greater number. They are called coolers, for the liquor is removed from the teache and 
 poured into these vessels to cool. Their size is such that, when filled, the syrup will cool at that rate 
 which is most favorable to a proper crystallization of the sugar. The more gradually the syrup 
 cools the larger will be “ the grain” of the sugar, and the more easily will the molasses be drained 
 from it. 
 
 The degree of concentration of the syrup is determined by several methods, of which the best is 
 called the proof by touch. A small portion of the syrup is taken from a ladle or stirrer on the. end of 
 the thumb, and the middle finger is then brought in contact with it, and again separated from it. If, 
 in this case, two drops of liquid separate, that on the thumb below being the larger, the concentration 
 is as yet weak. If the drops become nearly equal and do not separate until the finger and thumb are 
 drawn widely apart, the concentration is stronger. The third state of concentration is where, by the 
 separation of the finger and the thumb half an inch, a thread is drawn out, which finally breaks below ; 
 the end of the thread becomes club-shaped, and rises slowly towards the finger. In the fourth stage, 
 the same thing occurs at a greater distance, the end is folded backwards, and the thread has the form 
 of a ribbon or long strip, which rises more rapidly than before. In the fifth and last degree of concen- 
 tration, after a greater separation, the thread breaks, being very fine at the end which turns aside and 
 twists up like a cork-screw. It does not fold itself upon the upper part of the thread as before. A 
 little mote concentration prevents the thread from shrinking at all upon itself. 
 
 The scum which is removed from the cane-liquor and syrup is taken, together with the feculencies 
 collected in the clarifiers, to the still-house, where it is converted into spirit. The furnace is maintained 
 at a uniform heat, day and night, from the commencement of the grinding season in November, till its 
 conclusion in January, stopping only a few times that the kettles may be scraped from the accumula- 
 tion of rust, lime, and earthy impurities, which collect upon them, and which, if not occasionally re- 
 moved, cause them to crack. 
 
 From the coolers the sugar is taken to the curing-house, which is a large building contiguous to the 
 boiling-house. In a cavity in the lower part of the curing-house is the molasses cistern. Over this cis- 
 tern and on the floor of the boiling-house, is an open frame-work of strong joists, leaving a gangway in 
 the middle. Upon these joists are supported a series of hogsheads, into which the sugar, when suffi- 
 eiently crystallized in the coolers, is removed, and the molasses drained off through holes in the bottom. 
 This molasses flows through a trough below into the cistern. The curing-house is built so capacious as 
 to hold all the sugar which can be made in three or four weeks, or till it is freed from the greater part 
 of its molasses. Some molasses will always remain entangled in the crystals of sugar, but when tol- 
 erably dry, the sugar is removed from the curing-house for shipment. The sugar thus manufactured 
 is called muscovado or raw sugar, and is the material used by sugar-refiners in making white or loaf- 
 sugar. 
 
 Description of Reeds sugar boilers, with the method of preparing them for use . — In every process 
 for the manufacture of sugar, there must be a series of boilers, evaporators, coolers, and the other 
 arrangements which have already been described. The peculiarity of Reed’s boilers consists chiefly in 
 the mode in which the fire is applied. 
 
 In Fig. 3380, d is a valve which closes either the flue de or the open passage' represented by the 
 bent arrow. Another valve e is represented as open, which, when let down, closes the flue e d. The 
 valve c affords a direct communication with the chimney through the flue c a h. The valves c and a 
 being opened, the fire is kindled beneath boilers Nos. 2 and 3, on the grate m n. When the fire is 
 sufficiently kindled, the valve c is shut, e is opened, as shown in the figure, d is shut down over the 
 space represented by the bent arrow, and thus the heat from the fire passes down beneath the teache, 
 and then turns upwards, as shown by the bent arrow e, through the flue ed, and passes on through the 
 flues beneath Nos. 3 and '2.- If the valve b is thrown entirely open the heat will ascend through the 
 grate immediately above, and pass around in the flue under No. 1, and, descending in the direction rep 
 
 * These flues pass through the boilers. 
 
682 
 
 SUGA.R BOILERS. 
 
 resented by the bent arrow, will finally pass through the flue a A into the chimney. Two valves are 
 represented by the letter a, and two by the letter b, corresponding to the two clarifiers represented by 
 No. 1. The object of this double arrangement is to shut off the heat from either clarifier, according to 
 circumstances. 
 
 * 
 
 The flue eel passes through the teache and is composed of a series of pipes, as represented at I ' , ir 
 Fig. 3879. The valve e is so constructed as to close all these pipes, and corresponds to the valve R, 
 in Fig. 3379. The valve d is made in the same way. The flues beneath Nos. 3 and 2 pass through 
 these boilers, as represented in G- and H, in Fig. 3379. The flue beneath No. 1 has a different con- 
 
SUGAR BOILERS. 
 
 635 
 
 st-ruction. In this two large pipes pass through each clarifier, as is shown at ffff Fig. 3380. By 
 the valve b the fire may at any time be entirely, or in part, cut off from the clarifiers, and by the valve 
 e from the teache. 
 
 The remaining arrangements are represented in Fig. 3319. XXX W are doors opening to the fur- 
 nace, by which a fire may at any time be kindled directly under each of the boilers or under the clari- 
 fiers. Z Z Z are doors for removing ashes from under the boilers. O is a stop-cock for drawing oil 
 syrup from the teache. The stop-cocks for drawing off the syrup from the other boilers have been 
 already mentioned. 
 
 To prepare the boilers for use . — AB and 0 are at first nearly filled with water, D and E are filled 
 with cane-juice. The fire is then kindled, and the heat is made to pass, as described above, through 
 all the boilers, and one of the clarifiers D, but not through the other, E. When the cane-liquor in D is 
 heated nearly to the boiling point, the heat is cut off from this and made to pass through E. The 
 water is now drawn off from boiler C, and the clarified cane-juice from D is drawn off into this boiler 
 L) is then again filled with cane-liquor. 
 
 When the cane-liquor in Eds sufficiently clarified, the contents of C are drawn off into B, the watei 
 of which has been previously removed. The liquor from E is then drawn off into C, and E is filled 
 with fresh cane-juice. 
 
 The liquor from D being ready to be drawn off again, the water is removed from the striking-teaehe 
 A, and the syrup is drawn from B to A, from C to B, and from D to C. I) is filled with fresh cane- 
 juice, and all the boilers are now in operation. When the syrup in A is sufficiently concentrated, the 
 fire is cut off from this boiler by raising the valve d. Fig. 3380. The syrup is allowed to remain in the 
 teache for a few moments till it is somewhat cooled, and is then drawn off except 3 or 4 inches at the 
 bottom. 
 
 Advantages of Reed’s Boilers. 1. Economy of fuel . — In most of the tropical countries where sugar 
 is made, fuel has become scarce ; hence the great object of the planter is so to arrange his works as to 
 economize fuel. The usual arrangement for this purpose, is of a series of boilers in a horizontal flue. 
 The heat of the fire is thus, to a great extent, abstracted before it arrives in the flue. The saving of 
 fuel, in Reed’s arrangement, is produced by cutting off the fire when it is not needed. 
 
 Mere position cannot adapt the boilers to the different degrees of heat which they require, for there 
 is no gradation in this respect. When the liquor is first introduced into the clarifiers, a great amount 
 of heat is frequently necessary, on account of the large quantity of water which the cane-juice contains. 
 But, as the evaporation proceeds, the amount of heat required diminishes. In the striking-teaehe, 
 also, it is equally important to be able to diminish or cut off the heat at once. This is easily managed 
 in Reed’s method, and, at the same time, the heat is not lost, but is applied immediately to the evap- 
 orators Nos. 2 and 3, Fig. 3380. 
 
 2. Economy of time. — On many plantations, and on all at certain times, it is far more important to 
 hasten the conversion of cane-juice into sugar, even if this is done imperfectly, than to obtain a more 
 perfect article with a greater expenditure of time. It is often far more profitable to make a large 
 quantity of rather inferior sugar, than a smaller amount of the first quality. 
 
 Economy of time is important in another respect. It has been ascertained that sugar is rendered 
 dark and uncrystallizable more by the duration of boiling than by the intensity of the heat employed. 
 Slow evaporation by steam, for instance, instead of producing a better result, gives very dark and un- 
 crystallizable syrups. A rapid evaporation in 6 or 8 minutes, in the usual evaporating pan, renders less 
 of the sugar uncrystallizable, than a slow evaporation in the same pan continued for 40 or 50 minutes. 
 The same effect lias been found to take place even in the vacuum process, where the sugar is boiled 
 at a very low temperature. 
 
 Reed’s process secures this advantage in three ways. (1.) Evaporation takes place much faster 
 when the heat is distributed through the syrup by pipes, than when it is applied to the flat or round 
 bottom of the common boiler. For this reason steam-pipes are introduced into the syrup, in the vacuum 
 process, besides the steam which fills the double bottom of the boilers used in this process, and commu- 
 nicates heat from beneath. (2.) A much higher degree of heat can be used in this method than in the 
 one generally employed. In the common boiler, as the heat of the fire acts directly on the flat or 
 round bottom, the greatest care is necessary to prevent the sugar from being burnt, or from being ren- 
 dered uncrystallizable. If a high heat is employed, it is impossible to prevent this effect from taking 
 place to a greater or less extent. But, by distributing the heat through the syrup, as in Reed’s pro- 
 cess, the danger from this source is entirely removed. (3.) The whole arrangement is so easily man 
 aged by dampers, &c., that the five evaporating pans will require no more attendance than one of the 
 ordinary boilers. Much labor will thus be saved when it is most important to economize labor in the 
 hurry of gathering the crop and converting the cane-juice into sugar. 
 
 Simplicity of construction. — Compared with the other methods by which sugar is made in tolerable 
 perfection, this is remarkable for the simplicity of its construction. The vacuum processes of Howard 
 and others require a steam-engine, and are very complicated in all their parts. Only large plantations 
 can employ these methods, on account of their great expense, and the skilful hands required to work 
 them. The amount of sugar manufactured must be great to pay the interest on the cost of these ar- 
 rangements. The entire cost of Reed’s boilers will not very greatly exceed that of the arrangements 
 now generally employed, while it will be much less liable to accident. It can be managed by common 
 hands, as it requires less skill than even the common methods of making sugar. (Prof. A. F. Olmsted.) 
 
 Two vacuum-pans . — This mode of boiling sugar requires a careful defecation and filtration of the juice 
 and syrup through animal charcoal. The cane-juice, after having been defecated, is passed through 
 bone-black filters, collected in a vat from which the first vacuum-pan is supplied; when the cane-juico 
 is concentrated therein to 28° or 29° of Beaume, or thereabouts, it is drawn off into a vat from whence 
 the concentrated juice is passed again through bone-black filters, collected into a proper vat from which 
 
684 
 
 SUGAR BOILERS. 
 
 the second vacuum-pan is supplied, where it is then brought to the striking point. The vacuum-pans 
 used in this mode of boiling are like those described under the mode of boiling in open kettles and 
 vacuum-pans ; they are heated with low-pressure steam, and, consequently, the burning of the concen- 
 trated saccharine liquid is thereby obviated. When the operations of defecation, filtering, and boiling 
 are well managed, the sugar is equal in every respect to any made in any apparatus of the most im- 
 proved method. By this mode of boiling sugar the consumption of fuel is as great as with common ket- 
 tles. These kinds of vacuum-pans require a great quantity of fresh water for condensing; and in places 
 where water is scarce, vacuum-pans of this description cannot be employed. 
 
 Degrand's apparatus . — Degrand’s system consists of a condenser. The vapors arising from the juice 
 or syroD boiled in a vacu»m-pan and condensed by means of a serpentine tube, over which a film of cold 
 juice is continually kept flowing, which absorbs the latent heat of the vapor within the tube, and a por- 
 tion of the water from the juice passes off as vapor in the air. Degrand's condenser serves the double 
 purpose of a condenser and evaporator. 
 
 There are only two of Degrand’s apparatus in Louisiana. They were constructed at the Novelty 
 Works, New York, and are more commonly known as Derosne’s apparatus; but Mr. Degrand is the 
 eal inventor and patentee of this apparatus, and Derosne it Cail are only the constructors and assignees 
 jf his apparatus for the north of France and the colonies. 
 
 The Degrand apparatus in operation in Louisiana have vacuum-pans with a very large heating sur- 
 face, and heated with low-pressure steam ; the air-pumps are larger than those used in the Island of 
 Cuba. The artificial draught of air is not made use of here, but the same result is obtained by the in- 
 jection of water between the condenser and air-pump ; this increases somewhat the consumption of fuel, 
 but the vacuum obtained in that way is as perfect as by means of the draught of air ; and the sugar 
 made with this apparatus is as good as any made in Louisiana. 
 
 In the beet-sugar manufactories in Germany the manufacturers were beginning to abandon its use, in 
 consequence of the practical difficulties in distributing the beet-juice regularly over the serpentine; and 
 in case one of the many tubes which form the serpentine has the slightest deviation from the straight 
 line, the juice will concentrate more at such depressions, and disturb the regular distribution of juice 
 over the tubes. When a leak happens, the juice or syrup is rapidly absorbed into the interior of the 
 tube on account of the vacuum, and causes a considerable loss. It is likewise found that the economy 
 of water for condensing is not so great as was anticipated, and finally it was concluded to return to the 
 former plan of boiling in common vacuum-pans. 
 
 The consumption of fuel by a Degrand's apparatus is If to 2 cords of wood for every 1000 pounds 
 of sugar produced. In the Island of Cuba this apparatus takes off the wdiole crop with the bagasse 
 alone ; however, some require great quantities of wood besides the bagasse. 
 
 Mr. Derosne obtained a patent in Europe in 1836, and in America in 1845. 
 
 The following description of the mode of working his apparatus is taken from his patent. 
 
 The juice which is taken from the mills is defecated in pans or boilers, a row of which is shown at 
 fff Fig. 3382. In Fig. 3381, the elevation of one of these boilers,/, is represented. The juice from 
 the mill passes into a reservoir d, that is connected by a pipe d' with an air-tight cylinder e, in which 
 pipe there is a stop-cock that is turned by a long handle d", by turning which the cylinder e can be 
 filled, and the communication can be afterwards cut off by admitting steam from the generators or boil ■ 
 ers, (shown in Fig. 3382, G, in dotted lines, that supplies steam to the engines and heating apparatus or 
 the whole manufactory,) into the top of the cylinder e. The juice is forced through a pipe e', in the 
 bottom of said cylinder, up into the clarifying boilers/, which is constructed wfith a double bottom, be- 
 tween which steam is admitted by the tube a' from the generator ; the condensed water being returned 
 to the boilers by a force-pump through the pipe b' . The construction is common, but the employment 
 
SUGAR BOILERS. 
 
 085 
 
 of the series of these pans, for this purpose, has never before been done, or the juice cl'tified, as about 
 to be described. 
 
 When the cane-juice has reached the point proper for receiving the clarifying mixture, which point is 
 from 60° to 63° of Beaume, it is added. This composition is made by a compound of the sulphate of 
 alumine of the cheapest character, either with or without the presence of iron, which is formed by mix- 
 jng sulphuric acid with aluminous earth, and adding thereto lime, potash, or other similar salt, and a 
 quantity of liquified blood, either fresh or dried, being incorporated into the precipitate. This is united 
 with the juice by carefully stirring it while pouring in the mixture, and clarifies it; or, instead of this, 
 dme alone can be used, as in the former processes, the quantity being much greater than that used in 
 the old colonial mode of proceeding, as, in this system, there is nothing to fear from an excess of lime, 
 which a subsequent part of the process perfectly corrects to any extent that it may have been found 
 necessary to use it, in order to obtain a good clarification. The steam is kept on until the juice begins 
 to boil, and when this point is reached, the steam is cut off. The result of this is, where the mixture is 
 used, that at the top of the boiler ff a thick and solid coat of scum is formed, and only a very small 
 quantity of matter is precipitated to the bottom of the boiler. In a few minutes the liquor will have 
 become clear, and can be drawn off' through a tube m, by turning a cock in the bottom by means of a 
 key in', when it can be ascertained if the liquor is limpid. A small quantity of thick matter usually 
 issues from the tube first, but it soon runs clear. By this mode of proceeding we avoid all the trouble- 
 some labor of skimming, &c. The juice, after leaving the tube m, passes into a gutter M which commu- 
 nicates by a pipe c with another reservoir j, by which the filters, hereafter described, are charged with 
 the juice. 
 
 When all the clear juice is drawn off, the scum and the remainder is drawn into a reservoir under- 
 neath ; after which bags are filled with it, and the syrup is drained and pressed out of it. The clarified 
 cane-juice in the reservoir F is next to be filtered through animal charcoal in grain; and this filtration 
 constitutes one of the most important operations of the manufacture — it purifies the juice and furnishes 
 the means for readily obtaining sugar of the first quality. In Fig. 3381 eight of these filters are repre- 
 sented, li h h, all of the same construction ; the same are shown in Fig. 3382. They are constructed to 
 contain about one and one-seventh tons of animal charcoal. They are made of sheet-iron or wood lined 
 w T ith copper, of a square form, narrowing slightly towards the bottom. At the lower part there is a grat- 
 ing, leaving a small space between that and the bottom, through which the filtered liquid flows. On 
 this grating is placed a thick blanket for the purpose of supporting the charcoal, which should be suffi- 
 ciently large to allow the edges to be pressed against the sides ; a thick layer of charcoal is then spread 
 over this blanket firmly and evenly, after which another layer of charcoal is put on, care being taken to 
 equalize it with a trowel as it is thrown in, and the filter is filled thus to about four and a half feet in 
 depth ; the upper surface is then carefully smoothed, and it is ready for uee. • 
 
 A plate is laid on the place where the cock discharges the juice or syrup into the filter, in order that 
 t may spread horizontally over the surface without forming hollows therein. The syrup penetrates the 
 animal charcoal, and drives the air down before it, which is discharged from a pipe that leads up from 
 the space below the grating to the top of the filter. The syrup, after passing through the grating and 
 having deposited all its impurities in the filter above, is drawn off through the cock in the bottom, from 
 whence it is conducted to a reservoir, shown in Fig. 3382 by the letter k, from which it is elevated by a 
 cylinder l into a reservoir l'. This cylinder or monte-jus is made and operates precisely the same as 
 that previously described and shown in Fig. 3381. 
 
 From the reservoir l' of Fig. 3382 the juice is conveyed to the evaporator, which is one of the most 
 important parts of this invention, and is constructed as follows : Fig. 3382 (O' C" O'") being a top plan, 
 and Fig. 3381 a side elevation thereof; it consists of a double or triple series of horizontal tubes of 81- 
 inches in diameter, and about 300 feet in length, each series being placed one over the other, forming 
 two or three parallel lines ; the tubes of each series are connected together at each end, so as to form 
 one long conductor for the steam, by which they are heated. The tubes of each series are supported by 
 two upright posts, one at each end, which are connected at the top by a cross-beam or cup-brace just 
 under this beam ; there is a bracket on the inside of each post which supports a triangular-shaped 
 trough or distributor P, that extends from one to the other, the lower edge of said trough being serrated 
 without being cut through, and standing directly over the centre of the upper tube of the series, C' ; one 
 side of this trough has a row of small vertical oblong holes in it, through which the juice received from 
 the reservoir V percolates, and guided by the lower serrated edge, drops upon the top of the upper tube, 
 spreads itself around it, and then falls on the next, and so on to the bottom, passing over the entire sur- 
 face of the tubes, which, by the heat of the steam within them, serve to evaporate some of the aqueous 
 portions of the juice that is then received at the bottom in a receiver V , and ultimately into the reser- 
 voir u, and the juice being heated by the tubes, and being exposed to the action of the air in a state of 
 extreme division, is evaporated, and conducted in a proportion determined by the rate at which it es- 
 capes from the distributor above, as it falls into the receiver t'. 
 
 A is a pan of a common construction for boiling by steam in vacuum, with the usual fixtures attached 
 thereto ; a vacuum is formed by an apparatus hereafter named, in the boiler A, and by opening a com- 
 munication between the boiler and the reservoir u through the connecting-pipe d", which extends from 
 the bottom of said reservoir to the pan, the juice contained in the reservoir rushes into the pan. As soon 
 as 'the pan is filled, which is ascertained by means of the glasses in the lid of the pan, the pipe d" is 
 stopped, and the steam is introduced into the respective heaters of the boilers from the steam-generators. 
 
 The steam which rises from the juice in the pan into the cup Id, passes through a tube a into a large 
 upright cylinder B, in which any saccharine matter is separated from the steam which has been forced 
 up with it. From the vase B the steam passes by the pipes e" into each series of tubes above described, 
 (lettered C' C" C'",) entering the upper tubes of the series and passing out of the l;wer ones on the op- 
 posite sides ; the steam, in passing through the tube 0, is condensed by the juice which runs down over 
 the outside, the apparatus thus performing the two-fold operation of evaporating the juice and forming 
 
686 
 
 SUGAR BOILERS. 
 
 ft condenser for the steam rising from the vacuum-pan. The steam, when condensed into water, runs 
 out of the lower tubes, as above named, into an injecting -cylinder D, where, if the condensation is not 
 perfect, water can be injected to complete it ; from the cylinder D the water of condensation, <5rc., is 
 drawn off by the action of the air-pump attached to a steam-engine, indicated in the drawing by E. 
 The pump and cylinder D, above named, may be omitted, and a ventilator placed in their stead ; but 
 the vacuum will not in that case be so complete, although the expense of the apparatus is somewhat 
 reduced. Instead of attaching the condenser with the vacuum-pan, as above described, it may be con 
 nected with the exhaust-pipe of the steam-engine. 
 
 As the depth of juice in vacuum-pan A is reduced by evaporation down 10 the heaters inside, a fur- 
 ther supply is to be admitted from u through the pipe d", as in the first instance; and when the juice 
 under evaporation acquires a density of 2I 0 or 25° of Beaume, it must be drawn out of the pan, the 
 passage of the steam to the heaters being first cut off, and the vacuum therein destroyed. 
 
 The syrup at 25° then passes through a movable spout L, which is directed into another spout N, and 
 thence into the reservoir I, after which the boiler is charged with juice from u, and the process again 
 proceeds as before. During the operation of emptying and refilling the pan, the time is so short as not 
 to require the stopping of the flow of the cane-juice over the outside of the tubes C' C" O'". 
 
 From the reservoir I the syrup is raised by means of a hand-pump J into a spout which is represented 
 at i, Fig. 3382, for feeding the filters before described. The syrup runs from the spout i into either of 
 the filters li through stop-cocks attached thereto for that purpose, and passing down through the filters, 
 it is soon after drawn off through the cock and received into the gutter i\ whence it is conducted into 
 the reservoir k', Fig. 3382 ; and when there is a sufficient quantity therein to fill the pan A, the other 
 processes are stopped, and the pan A is filled with the syrup from the reservoir k', by means of a pipe 
 u', which connects them by a proceeding similar to that for filling the pan from the reservoir u. The 
 evaporation of this syrup of 25° is then proceeded with until it is sufficiently boiled, which is ascertained 
 by the testing-rod of common form. When the syrup is in a proper state of condensation, the pan is to 
 be emptied by means of the movable spout L, through the spout N, into one or the other of the heating 
 pans shown by letter F. 
 
 The pans I’ have double bottoms, and are supplied with steam from the generators between the two 
 bottoms, by which they are heated, until the temperature of the syrup contained therein reaches 1 0° 
 Beaume, at which point crystallization almost immediately commences; and when it is quite deter- 
 mined, the mixture of crystals and syrup must be stirred with a wooden spatula, care being taken to dis- 
 tribute the crystal formed on the bottom and sides equally ; the matter is then, while in a liquid state, 
 ready to pour into the moulds. 
 
 In the process of filtration, herein before named, as soon as it is found that from the use of the filter 
 the syrup of 25° comes from it less pure than at first, it is stopped and turned into another filter; the 
 clarified juice is then admitted into the filter from spout j ; this drives the syrup still contained in the 
 filter down, and takes its place. When the degree of the flowing syrup is found to be reduced to 15°, 
 the juice flowing from the cock is directed into the gutter j, which conducts it into the reservoir lc, from 
 whence it takes its course as before indicated. _ ... . 
 
 When the animal charcoal is sufficiently exhausted by the filtration of the clarified juice, water is let 
 on to the filter, and assumes the place of the clarified juice in the same way as the juice did the syrup ; 
 by this means the greater part of the juice is recovered, the flow being stopped when the degree of the 
 liquid is too weak to be of value. _ . . 
 
 The coal is then taken out of the filter and conveyed to the revivifier, and the filter is again refilled 
 with fresh black. _ . 
 
 Ddrosne claims the employment of a series of horizontal tubes, placed one above another, in the man- 
 ner described, having a current of steam passing through them, and the cane-juice flowing over the ex- 
 terior surface, by which the steam is condensed and the juice is somewhat concentrated ; thus serving 
 the double purpose of condenser and evaporator as before described, said condenser being attached either 
 to the vacuum-pan or to the exhaust-pipe of the steam-engine. 
 
 milieux’s apparatus .— Norbert Rillieux, of New Orleans, invented an apparatus for boiling sugar m 
 vacuo? in which he uses the latent heat arising from one pan to boil the juice or syrup in succession in 
 another vacuum-pan of similar construction. To heat the first pan he uses the escape steam of the 
 
SUGAR BOILERS. 
 
 G87 
 
 steam-engine -which works the grinding-mill; the second, third, or fourth pan is heated from the vapors 
 arising from the second and third pans. 
 
 An air-pump produces the necessary vacuum. 
 
 Mr. Rillieux obtained letters patent for his invention in 1843, and for improvement in the same in 1 84f>. 
 
 The following description and figures will give a correct idea of the apparatus and its mode of working. 
 
 Rillieux’s boiling apparatus is composed of three or four pans. 
 
 The four-pan apparatus . — The cane-juice, after having passed the clarifiers and filters, flows into a 
 vat, from which it is pumped in the first pan A, through a pipe a, Fig. 3385, which leads to the back 
 part of that pan, on which pipe there is a stop-cock, which is opened or closed by means of a handle h 
 placed in front of the apparatus, where the man who manages the apparatus is placed ; and, in turning 
 
 that handle more or less, he can regulate the feeding of that pan, in front of which is a pipe r, Fig» 
 8383 and 3385, leading the cane-juice to the back part of the second pan B ; on that pipe and under th< 
 first pan is a stop-cock, worked by the hand d, by which the feeding of the second pan B is regulated 
 and in the front, on this second pan and below, is another stop-cock, worked by the hand e ; from that 
 stop-cocx a pipe e' leads to the back of pan 0, to convey the cane-juice, now at the density of 15° 
 Beaume, into said pan; and from this pan a pipe leads to a pump which draws the syrup, now arrived 
 at 28°, from the pan c, and forces it up to the clarifiers E E. In those clarifiers the syrup is heated up 
 to the boiling point and scummed ; from thence it passes through the bone-black filters G G, whence it 
 goes to a vat H, Fig. 3384, below, to supply the fourth or strike pan D. 
 
688 
 
 SUGAR BOILERS. 
 
 Now let us follow the steam : 
 
 The exhaust steam from the boilers goes through the pipe I, Figs. 3383 and 3384, to the first pan A. 
 Below that is another, K, which brings the direct steam from the boiler and feeds the clarifiers F F and 
 the pumping engine L. At M, Fig. 3384, is a valve which connects the two steam-pipes together, and 
 through which any quantity of direct steam wanted, besides the exhaust steam, can be let into the ex 
 haust steam-pipe I for boiling the juice. 
 
 The vapors arising from the cane-juice of the pan A are carried down through a pipe h, Figs. 3385 
 and 3386, and column i, in a cast-iron box, o 2 , steam-chest k. A part of this steam passes up through 
 the column l to feed the second pan B, and passes through the horizontal pipe m, Fig. 3385, and up the 
 column q to feed the strike-pan D. 
 
 The vapor arising from the second pan B passes through column n and steam-chest k 1 , and up through 
 the column o, to boil the pan C. The vapor from C D passes through the columns p 2 through the 
 horizontal pipe s, and brings the vapor to the condenser s, where it is condensed by means of a jet of 
 water; the vacuum being maintained through the means of an ordinary air-pump T. S is a pipe which 
 connects the pumping engine with the condenser, the third and fourth pan. 
 
 3385. 
 
 The waste water of the first pan A comes down through a pipe into an air-tight chest in the bot- 
 tom-plate of the pumping engine, from w’hich the force-pump u takes it and sends it back to the steam- 
 boilers. 
 
 The waste water of the second and third pans, which is the condensed water of the vapor arising 
 from the cane-juice in the first and second pans, passes through similar stop-cocks and pipes, which 
 carry it to the small air-pump U, which forces it up to a vat, where it serves for all the cleansings of the 
 establishment. _ ... , „ 
 
 Three-pan apparatus . — When the three-pan apparatus is used, the cane-juice is pumped into the first 
 pan A ; from thence to the third C ; the second, marked B, is omitted ; whence it is drawn off by the 
 
SUGAR BOILERS. 
 
 689 
 
 pump to the clarifiers, and the juice follows the same course as in the four-pan apparatus, above de 
 scribed. 
 
 The exhaust steam and the direct steam are let in the first pan by means of the valve M, above 
 mentioned, and the vapor arising from this pan feeds the pan C, and the third pan D, and the vapor of 
 the second C, and third D, goes as in the other apparatus already described to the condenser. The 
 waste water of the second 0, and third D, follows the same course as already described in the four -pan 
 apparatus, to the small air-pump. As the main part of the boiling in the apparatus is effected by the 
 exhaust steam of the mill-engine, the mill must be kept grinding at a uniform speed, and with a contin- 
 ually regular supply of cane ; and as the power of the engine is regulated by the difference of pressure 
 between the steam in the boilers and the steam in the exhaust-pipe, and, as that difference is regulated 
 by the weight, on the valve M, it follows that, in loading that valve M more or less, the different pres- 
 sure of steam, or what is called the effective pressure of the steam, is adjusted in such a way that the 
 mill will furnish as much cane-juice as the apparatus boils — in such a way that the clarifiers, filters, 
 and filtered juice-vat are always kept full. The liquid flows from the mill up to the clarifiers and down 
 to the filters, with the same S23eed as it comes from the mill, the cane-juice passing out of the aforesaid 
 vat as fast as it comes in, to supply the first pan, and from thence to the second pan, (or third, as the 
 case may be,) when it is brought to the density of 29° Beaumti, A small pump is attached to the en- 
 gine to take it out of that pan fast enough to keep the syrup at a certain height in it. 
 
 The syrup is pumped into one of the clarifiers E as high as the jacket reaches ; when that clarifier is 
 filled to that point the rest of the syrup is turned into the other, which is heated by letting in the steam 
 before it is full ; when the first clarifier has reached the boiling point, the steam is shut off, the scum 
 removed, and the liquid emptied by the cock W into a trough, and thence down to the filters. 
 
 The only operation which the attendants of the pans have to observe is to keep the juice or syrup at 
 the proper level in the first and second pans, and to feed them as well as the third pan in such a way 
 that the syrup be maintained at 29° Beaumfe in the second pan, (or third, as the case may be,) by open- 
 ing or closing tlie feeding-cocks when the syrup runs too thick or too thin, or when the juice is too high 
 or too low, and also to regulate the pressure of the steam by the valve M. It will be observed that 
 there are two sets of clarifiers EE — one set to boil the syrup, and the other set to defecate the juice as 
 it comes from the mill. 
 
 When the stop-cocks are regulated they require a constant watching by the person employed at the 
 pans ; but they remain sometimes hours without being moved, or the handles require to be moved more 
 than one-eighth of an inch to one or the other side to keep the cane-juice at the proper height, and the 
 syrup at its proper density. The cane-juice, when it leaves the mill, passes in a constant stream to the 
 clarifier E, from thence to the filters and pans, and returns again to the clarifier F, at syrup of 29° den- 
 sity, and from there it goes through the bone-black filters G G to the vat H, which again supplies the 
 strike-pan, and then, at last, the boiling is done by strikes, as the sugar-boiler calls it. 
 
 The juice goes from the first into the second in the three-pan apparatus, and from the first to the sec- 
 ond, and from the second to the third in the four-pan apparatus ; because, in the latter apparatus there 
 is more vacuum in the second than in the first, and more in the third than in the second ; and it is that 
 excess of vacuum which draws the cane-juice from one pan into the other. 
 
 The waste water of the juice-clarifier F F comes through pipe X in the steam-chamber of the first 
 pan ; on which pipe there is a three-way cock, which, when properly turned, sends it directly back to 
 the waste-water pipe t of the first pan. The waste water of the two other clarifiers E E comes directly 
 to the waste-water pipe t of said pan. When the second pan is boiling, the three-way cock is turned 
 to bring said waste water from the cane-juice clarifier to the steam-chamber of the first pan ; arid all 
 the steam arising from said waste water upwards mixes itself with the exhaust steam, and helps the 
 boiling of said pan ; the water flows to the lower row of pipes through the other end of the pan, and 
 mixes itself with the waste water of said pan, and goes down through the waste-water pipe f, mixed 
 with the waste water of the clarifier E E to the closed chest in the bed-plate of the pumping-engine, 
 from whence the whole is pumped back to the boilers in such a way that all the steam condensed in 
 the jacket of the cane-juice and syrup clarifier, and that which has been condensed in the pipe of the 
 first pan, is returned to the boilers. Now, as all the exhaust steam of the mill and pumping engine is 
 used for the boiling of the first pan, it follows that all the steam raised in the boilers, except the small 
 portions which escape from the leak of stuffing-boxes or safety-valves, is entirely condensed and ren- 
 dered available for heating the cane-juice and syrup in the clarifier, and the whole of the waste water 
 heated to the boiling point is sent back to the boiler. 
 
 In Rillieux’s apparatus the use of the latent heat is carried out more perfectly and fully, perhaps, 
 than in any other system known. 
 
 The first pan of his apparatus is heated by steam not exceeding a pressure of four to eight lbs. per 
 square inch, and the latent heat of the vapor from this pan is used to evaporate the syrup in the next of 
 the series of pans, and so on. We have seen from the description of this apparatus that he uses an air- 
 pump to form the vacuum, which is worked in connection with the various other pumps by a separate 
 steam-engine, which is placed under the apparatus. 
 
 Merrick & Town, of Philadelphia, assignees of N. Rillieux’s patent, carried the plans of the highly in- 
 telligent inventor into execution, and developed in its results its admirable adaptation to the purpose 
 for which it was intended. 
 
 The principle of the successive use of latent heat has been long known and applied for distilling and 
 evaporating, but it has never been applied in connection with vacuum, by which connection only the 
 rapid boiling required for the evaporation of saccharine can be obtained. 
 
 This is, therefore, an American invention, which will form a new era in the sugar-growing interest of 
 the United States. 
 
 Mr. Tli. Packwood uses three steam-boilers of ordinary size : the fire-grate extends only under two of 
 them; the third boiler is heated by a return flue, and this is the only fire employed about the whole 
 Vol. II.— if 
 
SUGAR BOILERS. 
 
 GOO 
 
 sugar-house, generating enough steam to work the grinding-mill, to heat the defecators, supply the ne- 
 cessary quantity of steam to the boiling apparatus, to work the engine for the air, juice, syrup, anq 
 water pumps ; making 12,000 lbs. of sugar in 24 hours. 
 
 The apparatus is solid and requires very small space, and has a pleasant appearance. 
 
 The sugar made with this apparatus is of a beautiful light straw-color, of tine large crystal, and free 
 from unpleasant odor, and commanding a good price and ready sale. 
 
 The price of a Rillieux apparatus varies according to the size ; a three-pan apparatus sufficiently 
 large to take off a crop of 440 hogsheads of first sugar, including clarifiers, bone-black filters, vat for 
 tiltered cane-juice and syrup, three boiling-pans, pumping engine, cast-iron and copper pipes, and all 
 expenses of setting up, is $11,000.* 
 
 A. Stillman patented an improvement in evaporating saccharine juices in 1843. 
 
 The invention consists in employing the surplus or waste heat from the " train” in generating steam 
 for grinding cane, pumping, or any other purpose for which it may be required. 
 
 To supply the deficiency of evaporating power occasioned by diminishing the train of kettles, he sub- 
 stitutes in their place any number of steam evaporators or clarifiers, into which is introduced the “ ex- 
 haust" or waste steam, from the steam-engine. This waste steam, to be made effective, must be intro- 
 duced into the clarifiers or evaporators under a pressure greater than that of the atmosphere, and the 
 effect will be in proportion to the jiressure. 
 
 The objects of this arrangement are, a saving of fuel and improvement in the quality of the product, 
 and the improvement in the latter respect will be proportionate to that amount of the process of clari- 
 fying and evaporating which is transferred from the ordinary kettles in contact with the fire, to those 
 making use of the waste steam. 
 
 Fig. 3387 is a section of the sugar- works in which are shown the application of the improvement, and 
 respecting only a general arrangement. A A are the steam-boilers so placed as to receive under them 
 the waste heat from the train ; B, the steam-engine ; E, pump for bringing the liquor from the reservoir 
 to the clarifiers through the pipe F. This pump is not an essential fixture, as the mill is more frequently 
 elevated to a height sufficiently for the liquor to run directly to the clarifiers. GG, the clarifiers; H, 
 the evaporator, which is of the same form and construction as the clarifiers ; IKL, a train of “ coppers” 
 or evaporators, such as are in common use ; M, fireplace for the train ; N, the flue, through which the 
 flame passes from the “ train” under the steam-boilers to the chimney ; O P is also a flue to the chim- 
 ney, so that the flame from the “ train” may be turned off from the steam-boilers at will ; R, exhaust 
 steam-pipe from the engine ; this pipe communicates with the pipes in the clarifiers or evaporators ; S, 
 the escape-valve, by which a pressure is maintained in the exhaust-pipe. 
 
 The clarifiers are rectangular boxes of sheet-iron, (boiler-plate,) the bottoms of which are double, so 
 as to form a steam-chamber a\ around the top they have a channel-way m, which forms the “skim- 
 ming-spout the skimmings, which it receives, are carried off by a pipe. In addition to the heating 
 surface obtained by the double bottom, there is above it one or more tiers of copper pipes. The method 
 of introducing them is as follows : on two opposite sides of the clarifiers is a cast-iron box riveted, which 
 forms the side chamber b b, and extends the whole length of the clarifier ; this chamber is closed by a 
 movable plate which is fastened by bolts ; these two opposite chambers are connected by the cross- 
 pipes e; the pipes are received into the chambers through “packing-joints,” so as to prevent any com- 
 munication between the steam in the chamber and the liquor within the clarifier. To the top of one of 
 the side chambers there is a cylindrical valve-chamber attached, which receives the steam from the ex- 
 haust-pipe on either side ; from the lower side of this valve-chamber is a steam passage communicating 
 with the chamber b ; this steam passage is opened or closed by means of a sliding-valve d. 
 
 When the engine is in operation, the waste steam passing through the exhaust-pipe R is admitted 
 through into the side chamber b , and from thence into the pipes c c. and also through apertures into the 
 bottom chamber a. The liquor in the clarifier is then exposed to the heating surfaces of the pipes c e, 
 and also of the “ false” or “ double bottom.” 
 
 Steam-pipes passing through the liquor have been before employed, but not in combination with the 
 double bottom. The advantage of this combination is this: by using the pipes alone, that portion of 
 the liquor beneath them would be in a great measure unaffected, whilst the double bottom above would 
 not give the necessary heating surface ; so that the combination is necessary to a perfect operation. 
 
 h and i are two valves ; one for discharging the clarified or concentrated liquor, and the other for 
 discharging -the sediment formed in clarifying. Their construction is as follows : the valve is the ordi- 
 nary “ puppet valve,” with a hinge on the upper side for attaching the rods ; the seat is fitted between 
 :he two bottoms of the clarifier and riveted to both ; the pipes for carrying the liquor and sediment arc 
 
 See De Row’s Commercial Review, p. 292, vol. 5 
 
SWITCH. 
 
 691 
 
 attached by fianches and bolts to the bottom of the seats. The valves will close by their own weight, 
 and the weight of the liquor above them will keep them tight ; the valves are raised by cords con 
 necting them to levers on the shaft R, which shaft is worked by a handle on the outside of the clarifier 
 
 The valves are so placed that the levers stand in opposite directions upon the same shaft, so that 
 both valves can never be opened at the same time. 
 
 S .the escape-valve, made like an ordinary safety-valve, and attached to the exhaust-pipe of the en- 
 gine. Its particular construction, however, is not essential, its purpose being to obtain all the useful 
 effect of the waste steam by confining it in the exhaust-pipe and clarifiers at any required pressure. 
 Suppose, for instance, that the engine is in operation, and the exhaust-pipe terminating in the clarifiers, 
 but in some part of the exhaust-pipe there is an opening into the air of a size equal to that of the pipe, 
 the steam, of course, would escape through the opening against the pressure of the atmosphere only ; 
 its effect in the clarifiers would then be very slight ; but when that opening is closed by means of a 
 loaded valve, by increasing the weight on the 
 
 valve, we may so confine the waste steam as to 3388 - 
 
 effect the entire absorption of its heat in the clari- 
 fiers or evaporators. 
 
 The operation of this apparatus is as follows : 
 
 The Hues N and P being closed by dampers, a 
 fire is made under the steam-boilers in the usual 
 manner. As soon as a sufficiency of steam is 
 generated the engine and cane-mill are put in 
 operation. The pump E is then put in operation, 
 and the liquor carried to the clarifiers G G, through 
 the pipe F ; the steam is then admitted from the 
 exhaust-pipe into the clarifiers ; and the liquor hav- 
 ing gone through the usual process of clarifying, is 
 discharged by means of the valves h h into the 
 evaporators H, and through that into the train of 
 coppers I K L, where the evaporation is to be 
 completed. These coppers or kettles being filled 
 with the clarified liquor, the furnace is closed, and 
 the fire started under the trains of coppers on the 
 furnace M, by which fire, besides effecting the 
 concentration of the liquor in the kettles, the steam 
 is generated in the boilers and the operation con- 
 tinued. 
 
 The steam-clarifiers may be used indiscrimi- 
 nately in clarifying or evaporating, as the case may 
 require. 
 
 If the train of coppers be very much diminish- 
 ed, more of the evaporation, of course, must be 
 carried on in the steam evaporator. 
 
 SWITCH. A contrivance of a variable rail by 
 means of which the cars on a railroad are passed 
 from one line of rail to another. 
 
 Fig. 3388 shows the method of operating. S S 
 are called the switch-bars, movable about the 
 point H, at which point they form part of the line 
 of rail of the straight track BBBB. These bars 
 are secured together by iron rods rrr; a rod r' is 
 connected to the short arm of a lever l, seen in 
 elevation in Fig. 3389 : by throwing this lever to 
 the right or left the switch-bars are moved so that 
 they form either part of the straight and right-hand 
 track B A, B A, or part of the straight and left- 
 hand track B 0, B 0. Where the rails cross at E 
 is the fixed casting called a frog, the use of which 
 to pass the flange of the wheel through the 
 curved rail is too obvious to require explanation. 
 
 This is the double switch connecting a main line 
 with a turn-out or track on either side, and wher- 
 ever the rails cross each other a frog is inserted, 
 bolted to the cross-ties. See Frog. 
 
 Innumerable forms of switch-bar and frog have 
 been devised for accomplishing the same purpose, 
 and several patents have been taken out for 
 switches called “safety switches,” the object of 
 which is to prevent the cars passing off the track 
 when through negligence the variable rail is left 
 in a wrong position. Mr. Nichols, of Philadelphia, is the patentee of a very efficient form of safetj 
 switch, as is also Mr. Tyler, of Worcester, Mass. 
 
692 
 
 TELEGRAPH. 
 
 TELEGRAPH, History of the. Soon after the discovery of the Leyden jar, in 1747, it was observed 
 that the shock, passed through twelve thousand feet of wire, affected persons placed at either extremity, 
 apparently at the same instant of time. The idea of the instantaneous passage of electricity was prob- 
 ably thus first received, and it was forced, by new observations, on the attention of all succeeding 
 electricians. 
 
 In 1794, Reizen proposed a telegraph, employing the spark, with seventy-six wires, or thirty-six 
 complete circuits, one for each letter and number. In 1798, Betancourt constructed a telegraph, also 
 employing the spark, which is stated to have been in successful operation, between Madrid and Aran- 
 juez, for twenty-six miles. This was the achievement of the close of the last century. The difficulty 
 of insulating free electricity made it impossible that any great results should be obtained from its use. 
 
 The first year of the present century produced the voltaic or galvanic battery. In 1809, Soemmering 
 improved this discovery by inventing a telegraph of thirty-five wires, which indicated the letters by 
 the decomposition of water, which took place under the eye of the observer, from little pins of gold. 
 He also caused the liberation of the gases to raise a cup attached to a lever, and thereby drop a weight 
 on a little platform, connected with chime machinery, so as to ring a bell. In 1816, Dr. J. R. Coxe, of 
 Philadelphia, proposed a similar decomposing apparatus, and confidently predicted the ultimate sue 
 cess of the telegraph. In the same year, Ronalds, in England, returned to the use of free electricity,, 
 inventing an elaborate telegraph, which was put into operation over eight miles of wire. 
 
 The first registering telegraph seems to have been constructed by Mr. Harrison Gray Dyar, of Long 
 Island, in 1826, who used the decomposing power of the spark, acting upon a fillet of paper, moistened 
 and stained with litmus, and moved by hand or clock-work. The passage of each spark from a con- 
 ductor to the paper produced a discoloration, and, by different combinations of marks thus made, any 
 signal could be transmitted and registered. This was a very important step in the history of the tele- 
 graph, and appears to be the origin of the system of telegraphic alphabets so. generally used in later 
 inventions. 
 
 In the telegraphs already referred to, it had been necessary to interpose the indicating apparatus in 
 the course of the circuit ; that is, to interrupt the circuit for a short space. This was obviated by the 
 discovery of the deflection of the compass needle by (Ersted, in 1819, and the discovery of the electro- 
 magnet by Ampere, in 1820. According to the first of these discoveries, a magnetic needle tends to 
 place itself at right angles to a wire in its neighborhood, through which a galvanic current passes. 
 According to the second, a piece of soft iron, placed in the axis or centre of a coil of wire, becomes a 
 magnet during the passage of a galvanic current through the coil. 
 
 In 1820 and 1822, Ampere proposed and fully described the use of the deflection of a number of 
 needles to constitute a telegraph similar to that of Wheatstone, now in operation, with a less number 
 of circuits, in England. From this time the subject became one of frequent suggestion among philoso- 
 phers. The deflective telegraph was, however, finally introduced into practice by Schilling, in Russia, 
 at the end of 1832, by Gauss and Weber at Gottingen, in 1833, and finally, on a large scale, by Wheat- 
 stone, in England, and Steinheil, at Munich, in 1837, or soon after. The credit of the first construction 
 of the galvanic telegraph belongs thus to Schilling, Steinheil, and Wheatstone, by the latter of whom, 
 with some of his English coadjutors, many of the practical difficulties in the modes of transmitting the 
 current were overcome. 
 
 The telegraph of Steinheil, which was in operation between Munich and Bogenhausen in the sum- 
 mer of 1837, seems to be the first electro-magnetic telegraph on record which employed a registering 
 apparatus. The deflection of his needles moved little levers, carrying pen-points, which marked dots 
 or short lines on a fillet of paper moved by clock-work, as had been done with common electricity pre- 
 viously by Dyar, and as was subsequently brought into use in this country by Professor Morse. 
 
 The deflective telegraph was still imperfect, each deflection of the needle requiring a very apprecia- 
 ble time to be accomplished. The use of the electro-magnet was the next step taken in advance. It 
 was not until the experiments, in 1830, of Professor Joseph Henry, now secretary of the Smithsonian 
 Institute, upon powerful electro-magnets, and the effect of long conductors, that this form of telegraph 
 became possible ; and in his first paper on the result of these experiments, he at once applied the new 
 facts to the idea of the construction of the telegraph. 
 
 In 1844, the registering telegraph of Professor S. F. B. Morse, employing the electro-magnet, was 
 introduced upon a line between Baltimore and Washington, the caveat to his patent bearing the date 
 of October, 1837. The first suggestion of this form of telegraph is claimed to have been made by Pro- 
 fessor Morse in 1832, and also, in its general character, by Dr. 0. T. Jackson. This telegraph, together 
 with the House telegraph, and the Bain decomposing telegraph, constitute the three systems now, for 
 the most part, in operation in this country 
 
 Description of the telegraph.. — Fig. 3390 represents a series of twelve pairs of Grove’s battery, such 
 as is generally used in connection with the telegraph. When a plate of platina and a plate of zinc are 
 placed in an acid solution, a current tends to flow from the platina to the zinc, through any conductor 
 
TELEGRAPH. 
 
 693 
 
 which may be so disposed as to connect the two. In the figure, the galvanic series is represented, cor,, 
 eisting of twelve single pairs, the zinc of each of which is connected with the platina of the next. It 
 may be considered that a current is produced by each of these pairs, which has, however, to flow in the 
 same direction, and fall in with all the others. Hence their intensity is multiplied twelve times. It is 
 by this means that the resistance to the passage of the current through very long conductors is over- 
 come. The number of pairs in the telegraph is always proportioned to the distance which the current 
 is to traverse, fifty or more being used on a line of two hundred miles. 
 
 Each pair of the battery consists of a pint glass tumbler, a cylinder of zinc, a small porous cylindri- 
 cal earthenware cell within the zinc, and a platinum strip suspended within the cell from an arm be- 
 longing to the zinc of the next pair. A solution of diluted sulphuric acid is used with the zinc, outside 
 the porous cell, and the cell itself is filled with nitric acid. The two acids are used on account of an 
 increase of power depending on a chemical reaction. The zinc cylinder is amalgamated with mercury, 
 to prevent its being acted upon by the acid when the battery is not in use. A solution of sulphate of 
 soda is sometimes added to the sulphuric acid, to assist in accomplishing the same object. This is the 
 most powerful form of battery known. 
 
 A battery, usiug copper and zinc plates in flat glass cells, has been lately employed on the lines of 
 the chemical telegraph in this country. The interval between the plates is filled with white sand. The 
 sand is moistened to the consistency of a paste with diluted sulphuric acid. This battery proves very 
 constant, and, though less powerful, is much more easily managed than the Grove battery. 
 
 Two screw-cups will be seen rising above the battery in Fig. 3390, one of which is the positive pole 
 or extremity of the series, the other the negative. To these the wires are attached which convey the 
 current. These wires, as first used in the telegraph, were of copper, which is a better conductor of gal- 
 vanism than iron ; but the liability to accident, from their want of strength, was so great, that iron 
 wires were substituted by Steinheil, in Germany, of a size sufficient to make up by their quantity for 
 the poorness of their quality as conductors. 
 
 The wires are usually supported on posts, from which they are insulated by glass supports or knobs. 
 They have been sometimes carried through the ground, insulated within a metallic tube. 
 
 Fig. 3391 represents the signal-key in its simple form. It is placed, when in use, in the course of the 
 conductors or telegraphic circuit, proceeding from the battery. When the hand depresses the key, it 
 comes in contact with the knob and metallic strip below, making connection between the two screw- 
 cups, and completing the batteiy circuit. While the key is depressed, a continuous current passes ; 
 but if it be depressed, and allowed to spring immediately up, only an instantaneous wave or impulse 
 is communicated. The use of the signal-key, in connection with the telegraph, was described by Am- 
 pere, in 1820. 
 
 3392. 
 
 The signal-key, in its more perfect construction, is represented in Fig. 3392. It consists of a lever, 
 mounted on a horizontal axis, with a knob of ivory for the hand at the extremity of the long arm, which 
 is at the right in the figure. This lever is tlirown up by a spring, so as to avoid contact with the button 
 on the frame below, except when the lever is depressed for the purpose of completing the circuit. A 
 regulating screw is seen at the extremity of the short arm of the lever, which graduates precisely the 
 amount of motion of which it is at any time capable. 
 
 3393. 
 
 The registering part of Morse’s telegraph is shown in Fig. 3393. Two screw-cups are seen on tne 
 board, intended for the insertion of the wires from the distant battery. Next the screw-cups is seen a 
 U-shaped electro-magnet, with coils of wire upon it, the ends of which, passing down through the board, 
 are connected with the screw-cups. Over the poles of the magnet is a little armature, or bar of soft 
 iron, attached to the short arm of a lever, whose long arm carries a point or style, nearly in contact 
 with the grooved roller above. The action which takes place, on depressing the signal-key at the dis- 
 tant station, is, in the simplest terms, as follows : A wave of electricity is transmitted over the wire of 
 the telegraph, arrives at the electro-magnet, and circulates through the coil of wire surrounding it. The 
 U-shaped soft iron becomes at once a magnet, (see Magnetism,) and attracts the little armature down 
 to it. The long arm of the lever is thrown up, and marks the strip of paper passing between it and 
 the roller. When the distant operator lets the signal-key fly back, and the current ceases, the iron 
 
694 
 
 TELEGRAPH. 
 
 of the electro-magnet losing all its magnetism, and the armature, with the lever, is carried back by 
 the action of a little spring, being a dot impressed upon the strip of paper. Should the distant opera- 
 tor hold down the key, a continuous current will pass, and a line is marked on the paper which mover 
 under the roller. 
 
 / 
 
 h 
 
 t — 
 
 The complete registering instrument, shown in Fig. 3304, is a large spool, on which the strip c4 
 paper is wound, and clock-work, with rollers, give the strip a steady motion onwards under the style 
 upon the lever of the electro-magnet. A bell may also be added, which is struck by its hammer on the 
 first motion of the lever, to draw attention. There is a stop-motion sometimes used, by which the clock- 
 work is brought to rest in a few seconds after the lever ceases to act, and which is released again bv 
 the first motion of the lever. 
 
 The annexed is the combination of dots and morse’s telegraphic alphabet. 
 lines on the fillet of paper used by Professor Morse 
 to indicate the different letters and numbers. 
 
 Between each letter of a word a short space is ^ p 
 
 allowed, between words a longer space, and be- 
 tween sentences a still longer one. Many short- c - - - 9 
 
 hand signals are also employed. 
 
 Where a long circuit is used, the resistance to 
 conduction, measured by the amount of electricity 
 which passes, is very great. The diminution of 
 the current is most sensible when tested through 
 the first few miles of wire, the amount which sub- 
 sequently passes appearing nearly constant for a 
 long distance. It is not, however, sufficient, in its 
 electro-magnetic effects, to work one of Morse’s 
 registers directly. The current, which has trav- 
 ersed a great length of wire, can only move the 
 lever of the electro-magnet sufficiently to bring a 
 platina point in contact with a little platina disk 
 placed opposite to it, so as to complete the circuit 
 of a local battery, which works the register with 
 energy. This is the principle of combination of 
 
 circuits, and constitutes the important invention n _ | 
 
 of the receiving magnet and relay or local battery, 
 
 as they are familiarly known in connection with Morse’s telegraph. 
 
 The” effect of the combination of circuits is to enable a weak or exhausted current to bring into action, 
 and substitute for itself, a fresh and powerful one. This is an essential condition to obtaining useful 
 mechanical results from electricity itself, where a long circuit of conductors is used, and accordingly it 
 received the attention of early experimenters with the telegraph. This principle seems to have been 
 first successfully applied by Professor Joseph Henry, of Princeton College, in the latter part of 1836. 
 He was thus enabled to ring large bells at a distance, by means of a combined telegraphic and local 
 circuit. In the early part of 1831, Wheatstone, in England, used a combining instrument, which con- 
 sisted of a magnetic needle, so arranged as to dip an arch of wire into two mercury cups, when deflected 
 by a feeble current, thus completing the circuit of a local battery, which struck a signal-bell. Davy 
 patented in England, in 1838, a system of combined circuits, for four different purposes connected with 
 his telegraph. He brought into action a local circuit, 1st, to discolor or dye, by electro-decomposition, 
 the calico on which he registered his signs ; 2d, to actuate an electro-magnet regulating the motion ol 
 the calico ; 3d, to direct the long or telegraphic circuit to either of two branches, by means of a receiv- 
 ing instrument placed at their point of meeting, and operated upon from a distance ; 4th, he provides 
 for a complete system of relays of long circuits. His instrument resembled Wheatstone s, only the con* 
 .act was made by two surfaces of metal, without the use of mercury. 
 
 
 NUMERALS. 
 
 
 
 0 
 
TELEGRAPH. 
 
 695 
 
 The receiving magnet used by Professor Morse is a very slight modification of his register, the platiria 
 noint for completing the local circuit being substituted for the marking point. The magnet is sur 
 ■minded with helices of tine wire, which multiply the effects of the feeble current, and the whole instru- 
 ment is constructed with delicacy. By Morse’s patent of 1840, this is applied to the combination o( 
 long circuits, or the relay of currents ; and by his patent of 1846, it is applied to operating the register 
 by a local or office circuit. The electro-magnet, armature, and lever, constituting the chief part of botn 
 these instruments, is simply the electro-magnet of Professor Henry, described in 1831. 
 
 In a line of telegraph of several hundred or thousand miles, any number of receiving magnets may 
 be interspersed, as they do not interrupt the circuit. Each one of these may work a local register, and 
 thus the same message may be recorded at a multitude of places, practically at the same moment oi 
 time. If the receiving magnet is to effect a relay of currents, the motion of its lever brings into action 
 a powerful battery on the spot, which works the next receiving magnet in succession, and so on. 
 
 The use of the receiving magnet, however, for the purpose of relay of the galvanic force, may be hi? 
 pensed with by simply increasing the number of pairs, and distributing them in groups along the line 
 Thus Mr. Sears C. Walker, of the Coast Survey, writes, “ We have made abundant experiments on the 
 line from Philadelphia to Louisville, a distance in the air of nine hundred miles, and in circuit of eighteen 
 hundred miles. The performance of this long line was better than that of any of the shorter lines has 
 hitherto been. I learn, from au authentic source, that the same success attends the work from Phila- 
 delphia to St. Louis, a distance in circuit of one-twelfth of the earth’s circumference. The number oi 
 Grove’s pint cups used is about one for every twenty miles. It is natural to conclude, from this experi- 
 ment, that, if a telegraph line round the earth were practicable, tv’elve hundred Grove’s pint cups, in 
 equidistant groups of fifties, would suffice for the galvanic power for the whole line. The daily ex- 
 pense of acids, for maintaining this whole line, would be about five mills per day for each cup, or six 
 dollars per day for the whole line.” This distribution of the galvanic agency is frequently adopted in 
 the mode of placing one half of the necessary number of pairs at each extremity of the line. 
 
 The conductors hitherto spoken of have been exclusively the telegraph wires. It has now, however, 
 become a universal custom to use the earth as one-half of the circuit, and thus to employ but one wire. 
 T his is accomplished by carrying a wire down at each extremity of the line, and connecting it with a 
 metallic plate buried in the earth. The advantage consists not only in the economy of employing a 
 single wire to each circuit, but the loss from conduction by using the earth is vastly less. The use of 
 the ground circuit for the telegraph seems to be due to Professor Steinheil, of Munich. 
 
 In case of interruption of the telegraph wire, much ingenuity lias been shown by the association of a 
 through line and a test line, which latter communicates with a number of intermediate stations, and by 
 means of which the place of interruption can be readily ascertained, and the injury repaired. An in- 
 terruption is shown by the increased strength, the weakness, or the suspension of the current, which 
 each station has the means of examining, and from which the direction and nature of the accident can 
 be inferred. 
 
 A great source of irregularity in the action of the telegraph, in this country, has been atmospheric 
 electricity. The air being in different electrical states in different places, or thunder-storms taking place 
 in the course of the line, the insulated telegraph wires frequently become the medium of transfer of 
 atmospheric electricity. The safety of the operators, and even the regular action of the electro-magnet, 
 requires the use of conductors at the stations, which are nearly in contact with the wires, and which 
 communicate with the earth, so as to carry off' any excessive charge of electricity which might destroy 
 the instrument, or even endanger life. Much irregularity in the action of the telegraph still exists from 
 this cause. 
 
 These facts of general application to the electric telegraph have been considered here, as many oi 
 them were first developed and applied in this country, in connection with Morse’s register. This in- 
 strument, and the system connected with it, will always deserve credit for its early service in adapting 
 the telegraph to our climate and natural resources. 
 
 Lightning Protector. By L. Pocget, Maisonneuve. This is a beautiful and most important discovery 
 as an auxiliary in the perfection and full development of the electric telegraph. It is designed to drain 
 off the atmospheric electricity, which in certain conditions of the atmosphere accumulates in the wire, 
 seriously interrupting the transmission of signals by deranging the magnets, and often even melting and 
 destroying them. The beauty of the invention is in its simplicity : it consists in the discovery that 
 absolute alcohol, after having been subjected to proper chemical treatment, becomes a good conductor of 
 the high tension electricity of the atmosphere, while it is a non-conductor of the current generated by 
 the galvanic battery. 
 
 The apparatus consists simply of a glass tube, two inches in diameter by five in length, filled with the 
 prepared liquid, and a brass cap hermetically sealed to each end. The telegraph wire is made to pass 
 through the tube, and is surrounded by, and is in direct contact with the liquid. On one side of the 
 tube is introduced a wire connecting with the ground, which terminates in the liquid, but does not come 
 in metallic contact with the former wire. Its operation is as follows : 
 
 The accumulations of high tension electricity from the atmosphere pass along the wire until they 
 enter the tube, where they leave the wire, pass through the liquid to the ground wire, and thence to 
 the great reservoir of electricity, in the earth. Thus the line wire is relieved of the disruption dis- 
 charges, which otherwise would pass through and interrupt the proper action of the magnets, and the 
 battery current is left free from disturbance, and goes on to its destination, performing its mission with 
 fidelity. 
 
 Bain s Telegraph. The telegraph of Bain, represented in fig. 3395, is constructed on the principle 
 of the decomposition of a saline solution, through which a galvanic current passes, and is the most sim- 
 ple now in use. The indication of the current takes place here without motion. The circular tablet, 
 on which the writing is obtained, is moved by clock-work, at a uniform rate, under the wire, which con 
 stitutcs the telegraphic pen. But the pen itself never stirs. It bears silently on the tablet, and as the 
 
696 
 
 TELEGRAPH 
 
 eye observes the point of contact, now a blank space, and now a deep blue line, appears upon the re- 
 treating surface. This is the record of the intermitting current, sent over the wires from a distance. 
 
 In Fig. 3395 the clock-work which moves the tablet is seen on the left. Its motion is regulated by 
 n fly-wheel above, the vanes of which can be inclined so as to present greater or less resistance to the 
 an. A lever or break bears upon the axle of the fly-wheel, by moving which lever the clock-work may 
 be stopped, or allowed to go on. The circular disk, or tablet of brass, carried by the clock-work, is seen 
 on the right of the figure, inclined towards the observer. In the centre of the disk, occupying the shaded 
 portion, a spiral groove is cut, in which the guide to the pen travels. This guide is seen attached at 
 right angles to the penholder, which extends over the disk. The pen-wire is seen held by a little 
 clamp, descending so as to touch the tablet. This wire, of course, traces a spiral upon the outer ring 
 of the disk’s surface, exactly corresponding, in the distance of its lines, to the spiral groove within, 
 which serves as a guide. By this beautiful contrivance, the writing is disposed in a close spiral, occu- 
 pying but very little space. 
 
 The outer part of the surface of the disk, upon which the letters are represented in the figure, is 
 covered with a ring of moistened and chemically prepared paper. This may be renewed or removed 
 at pleasure. The penholder is connected with the positive wire of the telegrajih, and the tablet with 
 the negative. The circuit of conductors is completed by the moistened paper which intervenes, and 
 which the current accordingly traverses. This paper is moistened w'ith a solution of the yellow prus- 
 siate of potash, acidulated with nitric or sulphuric acid. The pen-wire consists of iron. When the 
 current passes, this pen-wire is attacked by the solution, and the portion of iron dissolved unites with 
 the prussiate of potash to form the color known as Prussian blue, which permanently stains or dyes 
 the paper. 
 
 A modification in the mode of marking has been introduced in this telegraph by Mr. Rogers, of Bal- 
 timore. He substitutes a pen carrying an ink which is decomposed by the current when in contact with 
 the brass disk, without any intervening paper. A superficial stain is produced on the metallic surface, 
 which is easily obliterated by friction. 
 
 3395. 3305. 
 
 In Bain’s telegraph, no receiving magnet is necessary. The current traversing the long wires is suffi- 
 cient to leave its trace upon the paper. There would be a disadvantage, however, in the use of this 
 telegraph, with a simple circuit, where it is desirable to register the same communication at a number 
 of different places, as the interposition of the paper, moistened with a saline solution, somewhat obstructs 
 the current. The receiving magnet and register used by Morse present a metallic conductor for the 
 current throughout, and they can, therefore, be multiplied without serious loss. To compensate this 
 disadvantage, a system of branch circuits at way-stations has been devised, in connection with the Bain 
 telegraph, by which communications can be received at various places at the same time. Morse’s in- 
 strument requires the time taken by the motion of the armature to make each mark. The decomposi- 
 tion in Bain’s instrument is instantaneous. This is an advantage where mechanical means are used to 
 complete and break the circuit W'itli great rapidity for the purpose of rapid communication. 
 
 An ingenious instrument to effect this object has been recently contrived. One of the circular me- 
 tallic disks of the register has its surface coated with wax or other composition. The lines and dots 
 which constitute the writing to be transmitted, are scratched through this so as to expose the metal, by 
 the operator, previous to completing the telegraphic circuit. This writing is effected, and disposed in 
 spirals around the disk, by simply putting a little signal-key in place of the pen-wire, and allowing the 
 uisk to revolve. The guide to the penholder, of course, carries the signal-key over the same spiral 
 which the pen-wire would describe on the disk. The signal-key lias a sharp or cutting point. which 
 removes the wax from the disk whenever the key is depressed. The usual motion for signalizing the 
 letters, therefore, prepares the impression of the writing, which is afterwards to be connected with the 
 telegraph, and transmitted with speed. This transmission is effected by restoring again the pen-wire 
 ’,o its holder, and allowing it to follow over the track just made by the signal-key. The battery being 
 connected, the wire completes the circuit whenever it touches the exposed metal, and breaks the circuit 
 when it rests upon the wax. The disks at both the transmitting and receiving ends are made finally to 
 
TELEGRAPH. 
 
 697 
 
 revolve rapidly, and the message is said to be thus communicated at the rate of one thousand or more 
 letters per minute. 
 
 The alphabet used by Bain is the same in principle as that employed by Dyar, Steinheil, and also bv 
 Morse, consisting of combinations of dots and lines. 
 
 The call, commonly used on the Bain lines, is represented in Fig. 3396. It consists of a U-shapea' 
 receiving magnet, placed horizontally on the board, with two helices of wire surrounding the leg3. An 
 armature, supported on an upright bar, so as to form a cross, is seen in the figure before the poles ot 
 the magnet. This is held back by a delicate spiral spring, graduated by a screw, which is also seen to 
 the left. Above are two circular plates of glass. The upright bar, armed with two little knobs, to 
 perform the part of a hammer, rises between these plates. When the armature is drawn to the mag- 
 net, it strikes one of them, and on being drawn back it strikes the other. As they are of different tone, 
 the repetition of this signal at once draws attention to the register. The duty of the operator is then to 
 set the clock-work in motion, and receive the message communicated. This instrument can be used 
 also as a receiving magnet, by placing a platinum point on the upright bar or pendulum, and a little 
 platinum disk immediately in front of it, so connected that the interval between the point and disk shall 
 constitute the break in a local circuit, an additional pair of screw-cups for the attachment of which 
 may be seen upon the base-board. When the armature approaches the electro-magnet, it closes the 
 local circuit, and when it recedes it breaks it. This is essentially the receiving instrument of Morse 
 and others. 
 
 This call is similar in purpose or principle to those used by Soemmering in 1811, Schilling in 1831, 
 and Henry, Steinheil and Wheatstone in 1836 and 1837. 
 
 Bain’s telegraph has been introduced very extensively into this country, especially in connection with 
 the network of lines constructed throughout the South and West by the enterprise of O’Reilly. 
 
 The receiving magnet in its improved form, Fig. 3397, used for the purpose of combining or connect- 
 ing circuits, is closely allied in its construction to the call, 
 and may therefore be described here, though already referred 
 to in connection with Morse’s telegraph. The armature is 
 mounted on an upright bar, and is seen forming part of the 
 cross just in front of the poles of the horizontal electro-mag- 
 net, surrounded with helices of fine wire. The long or tele- 
 graphic circuit is connected with these helices by means of 
 two of the screw-cups on the board. When the current flows, 
 the. armature is attracted to the magnet, and the upright bar 
 is brought in contact with the end of the horizontal screw, 
 seen at the top of the instrument. This completes a local 
 circuit, or branch circuit from the main battery, the conduc- 
 tors of which are connected with the instrument by means 
 of two other serew-cups, seen on the left of the hoard. The 
 points of contact of the upright bar and screw are protected from oxidation by the use of platinum 
 
 TELEGRAPHIC COMPOSITOR. The experience of Bain and others, in transmitting signals by 
 electricity, has demonstrated that the amount of time requisite to send a message to a distant place, is 
 not dependent upon the speed with which the electricity travels, but upon the time in which the human 
 hand can perform the proper manipulations. This, in actual practice, as experience with the various 
 methods in use has proved, has never reached an average of more than eighty letters per minute. In 
 the mean time the researches in electricity have shown, that when the wave or pulsation is given to the 
 current by the finger, it flies to its destination with the swiftness of thought, though its path may he 
 thousands of miles in length, and leading over precipitous mountains and through barren deserts. 
 
 The telegraphic compositor was invented by J. P. Humaston, of New Haven, Connecticut, and was 
 patented September 8, 1857. Its object is to increase the rapidity of manipulation so that it shall bear 
 some fair proportion to the capacity of electricity to record the signals. This is effected by an instru- 
 ment termed a compositor , which cuts the dots and lines of the telegraphic letters in a strip of paper of 
 about three-eighths of an inch in width. The message thus prepared is passed through the transmitting 
 instrument, which may be run at any speed requisite to keep pace with the record of the signals. This 
 speed with the magnetic instruments, is not more than about three hundred letters per minute ; this is 
 owing to the fact that they require machinery whose moving parts have weight and inertia. With the 
 electro-chemical mode, Mr. Bain, in 1846, transmitted as many as one thousand letters per minute be- 
 tween London and Manchester, England ; this was done by preparing the message strip by hand, and 
 then passing it rapidly between the poles of contact in the electro-chemical instrument. 
 
 The compositor consists of a key-board and twelve small steel cutters, which lie side by side ; the keys 
 are connected with the cutters in such a manner, that when any key is depressed, the cutters are carried 
 forward, and through the paper in the proper combination to form the letter which it represents. This is 
 done as rapidly as the touch can be made, and a single touch forms the letter with mathematical certainty 
 and accuracy. The compositor is to the telegraph wire what the font of type is to the printing press, 
 and any number of compositors may be used to prepare the messages which the capacity of the wire will 
 enable it to transmit. Thus far, its use has proved that one well insulated wire will transmit, per day 
 of 12 hours, 10,800 messages of ten words each. To do this with any system depending upon the, 
 manipulation or touch of the finger direct, would require the use of at least ten wires and twenty in- 
 struments. With the rapid extension and future development of the telegraph, this improvement fur- 
 nishes the means of reducing the tariff for telegraphing to a point low enough to bring it within the 
 means of every human being possessing sufficient intelligence to commit his thoughts to writing. It can 
 be used as an auxiliary to the magnetic telegraph, and is readily changed to any system of telegraphic 
 alphabet. Its usefulness however is greatly enhanced in connection with the electro-chemical instru- 
 ment, which records its signs by the simple pulsations of the electric current. 
 
698 
 
 TELEGRAPH. 
 
 Home's Printing Telegraph. This beau- 
 tiful invention may be considered as one of 
 the wonders of the age. Using but a single 
 wire, it is yet able to select and print in 
 order the letters of the common alphabet, 
 with a greater rapidity than the hierogly- 
 phic marks of Professor Morse, representing 
 the same letters can he produced. 
 
 This instrument is complicated, though 
 all its parts are simple. We shall try to de- 
 scribe it so that the mode of its operation 
 may be understood. A perspective view of 
 the instrument is shown in Fig. 3398, com- 
 prising both the transmitting and receiving 
 apparatus. The principle by which the dif- 
 ferent letters are signalized over the wire, is 
 the transmission of a given number of elec- 
 trical impulses for each letter, by the rapid 
 opening and closing of the circuit. This is 
 accomplished by means of the twenty-six 
 letter-keys, and the two keys for the dot and 
 dash, seen in the figure. Under the key-board 
 is a horizontal cylinder, which is kept in revolution by turning the crank and wheel, seen at the left of the 
 figure. At one end of this cylinder is a circuit-wheel or break-piece, having fourteen projections and 
 fourteen spaces, on which a spring, connected with the telegraphic circuit, bears. Consequently the 
 battery circuit is completed fourteen times and broken fourteen times with each revolution of the cyl- 
 inder. Under each key a projection or stop is placed upon the cylinder, in such a position that when 
 the key is depressed and comes in contact with it, the cylinder shall have performed such part of a 
 revolution as to have made and broken the circuit the number of times which represents the letter cor- 
 responding to the key. The motion of the cylinder is communicated by means of slight friction, and it 
 is accordingly arrested by depressing the key. This is the transmitting or “ composing” apparatus. 
 
 The receiving or printing apparatus is seen behind the key-board in the figure. There is one such at 
 each extremity of the line, to receive messages transmitted from the other extremity. But both are 
 left constantly in the circuit, so that the operator signalizes or prints the message which he sends both 
 at the distant end of the line and immediately before his eyes. The printing instrument which we are 
 examining is, therefore, a fac-simile of the one which receives the communication at a distance from the 
 operator at the key-board in the figure. 
 
 The printing apparatus consists of an upright rod-electro-magnet, inclosed in the metallic cylinder A 
 of a little engine, operated by condensed air, and moving an escapement at B ; of a type-wheel at C 
 of a printing eccentric and lever, the end of which is seen at D ; of a black coloring-band at E, and the 
 strip of printing paper at F F. 
 
 The electro magnet consists of a compound rod of several short pieces of iron strung upon a rod or 
 brass. This rod is inclosed in a tube of brass, attached to which, within, are several short tubes of iron, 
 corresponding to and reacting with the pieces belonging to the axial magnet. This whole system of 
 tubular and axial magnets is inclosed in a single helix of fine wire, connected with the telegraphic cir- 
 cuit. The tube is fixed, but the compound rod is movable, and attracted downwards by several co- 
 operating reactions when the current passes. This rod is suspended by a cross-wire, which may be seen 
 stretched across the top of the cylinder A, and acts as a spring, drawing the rod back after the current 
 has ceased to act. A very rapid vibration of the rod is thus obtained, corresponding to the opening and 
 closing of the circuit effected at the transmitting end of the line. 
 
 Connected with the wheel is a condensing pump at G, which keeps up a supply of condensed air. 
 At the upper part of the electro-magnetic rod is a collar- valve, which changes the direction of the cur- 
 rent of condensed air with each vibration of the rod, though these vibrations are only l-64th of an inch. 
 The air is thus admitted to opposite sides of the cylinder of a little atmospheric engine, which, by means 
 of its reciprocating motion, permits the action of an escapement, tooth by tooth, and the corresponding 
 revolution of the type-wheel, which is impelled by a spring kept wound up by the manual power em- 
 ployed at the crank and wheel. 
 
 The result is that the type-wheel, which has twenty-eight teeth, revolves just as far as the cylinder 
 attached to the circuit-wheel, at the distant extremity of the line, has been permitted to revolve by de- 
 pressing one of the keys. Each break, as well as each completion of the circuit, thus corresponds to a 
 letter. It only requires that the instruments at both ends of the line should be set to the same letter, 
 and then the cylinder at one extremity and the type-wheel at the other, regulated by the pulsations ot 
 the current, will always revolve at the same rate ; and if the cylinder is stopped at any one point rep- 
 resenting a letter, the type-wheel is stopped at the same point, and presents the type which it carrie 
 on its periphery to the strip of paper in front of it. 
 
 When the type-wheel stops, an eccentric, actuated also by the local power at the crank and wh< 
 brings the black band and paper forcibly against the type, and leaves the impression of the let 
 The paper is then carried on just the distance of a letter, and is ready for another impression. Roman 
 letters are thus printed over a long line at the rate of from one hundred and fifty to more than two 
 hundred a minute. 
 
 In the figure the letter A will be observed at a little window above the type-wheel. This letter is 
 >n a letter-wheel, connected with the type-wheel below, so that the letters may be presented to the 
 
TELEGRAPH. 
 
 C9S 
 
 sight at the same time as printed ; or the printing eccentric may be detached, and only the visible 
 letters read. 
 
 The action of the electricity in this telegraph is merely to produce correspondence of motion in ma- 
 chinery at different ends of the line, in the same manner that uniformity of rate has been secured in 
 clocks at different places, regulated by the electro-telegraphic current. All the mechanical results of 
 House’s telegraph are produced by local mechanical power. For this purpose, clock-work, having a 
 regular rate, would be preferable to manual power. 
 
 Horn's igniting telegraph . — The register invented by G. H. Horn employs a principle never before 
 applied to the telegraph, namely, the heating or igniting effect of electricity. When an electrical cur- 
 rent flows through a fine platinum wire it ignites it, or brings it to a red-heat. If this wire is bent, as 
 at A, in the figure below, so as to be in contact, for a short distance, with a moving fillet of paper, it 
 will burn a hole through the paper when the current passes. This can be done with great rapidity, so 
 as to represent probably a hundred linear letters per minute. 
 
 3399. 
 
 This instrument is shown in Fig. 8399, the greater part of which consists of the clock-work, spool, <5rc, 
 required for moving the paper. Above the clock-work are two pillars, supporting an axis, upon which 
 is the adjustable wire-holder, the lower extremity of which is seen touching the fillet of paper. By 
 means of the connections and insulations of the pillars, axis, and wire-holder, the platinum wire, which' 
 passes over a little slip of porcelain at the end of the wire-holder, becomes part of the circuit, with 
 which the two screw-cups on the right of the base-board are connected. When the wire needs adjust- 
 ment, the wire-holder can be turned up on its axis. The bed supporting the fillet of paper is also ad- 
 justable, so as to regulate the contact between the wire and the paper. 
 
 This register requires a quantity current to produce the effect of ignition, and therefore needs a re- 
 ceiving instrument and local battery, to be operated by the telegraphic circuit. 
 
 3400. 2401. 
 
700 
 
 TELEGRAPH. 
 
 of this reaction is so great, that it has been successfully applied by Prof. Charles G. Page, of Washing- 
 ton, to the propulsion of machinery on a large scale. 
 
 The axial telegraph is represented in a simple form in Fig. 3100. The U-shaped iron rests upon a 
 spring, seen on the board. A style attached to the iron, projects up between the coils so as to be nearly 
 in contact with the roller, under which the strip of paper is made to pass. A little rod or armature of 
 iron, placed across the top of the coils, causes the soft iron to move in obedience also to electro-magnet- 
 ic attraction, somewhat increasing the power, but introducing a new and unnecessary principle into 
 the reaction. The axial telegraph in its complete form, is represented in Fig. 3401, where the spool 
 and clock-work for the movement of the paper are added. 
 
 The axial motion is due to the deflective power of a coil, as in the telegraphs of Amphere, Steinheil, 
 and Wheatstone, and not to electro-magnetic attraction. This instrument requires, on a long line, the 
 intervention of a receiving instrument and short circuit. 
 
 Telegraph , Hughes. The Hughes instrument consists of a train of clock work, keys for closing the 
 circuit, an electro-magnet, and a vibrating spring to govern the type wheel, which revolves by aid of the 
 train of wheels. The clock work consists of four cog wheels, turned by a weight, which turns a shaft 
 with a wheel, upon which are engraved the letters of the alphabet. This wheel is inked by a small roll- 
 er. Below the type wheel a small press moves the paper to be printed upon against the letters. This 
 press moves only when the armature of the magnet acts by a current of electricity being sent along the 
 line. 
 
 The magnet of the Hughes instrument is a peculiarly simple and effective arrangement, by which 
 electricity is made to work at its highest development. Electricity only holds the armature whilst in 
 contact. As soon as it is set free by the distant operator closing the circuit, it falls against a detent 
 which brings a small cam in play, and restores the armature to its resting place in contact with the 
 electro-magnet. This operation is performed every letter that is printed, the magnet never acting until 
 a letter is sent, and then only once to each letter. 
 
 The principle of making all the instruments keep exact time with one another, so that they always 
 present a certain letter opposite the press at the same instant, and also to revolve rapidly, has been ac- 
 complished by the union of a well known law in acoustics to mechanics : thus a certain number of vi- 
 brations per second produces a certain musical tone ; if these two instruments have each a vibrating 
 spring of the same tone, the two instruments must always revolve in exact time with each other. 
 
 These type wheels, revolving by means of clock work, carry around with them a circuit closer, which 
 travels over twenty-eight pins corresponding to the letters upon type wheels ; if any of these pins are 
 touched by corresponding keys, the circuit is closed at the moment the closer passes that point. The 
 armature immediately falls off, opens the detent which locks the press to the wheel work ; this moves 
 up the press, and when the letter is printed unlocks itself until again locked by the action of the arma- 
 ture. 
 
 The fact of the possibility of writing both ways simultaneously on one wire has been fully demon- 
 strated. This is accomplished by the arrangement of the battery, so that it does not affect the magnet 
 at the office sending, but the instant that a distant office puts on battery the magnet acts ; thus each 
 magnet acts only from the distant battery, and is not affected by its own writing, whilst it receives per- 
 fectly what is sent to it. Another great feature in this machine is the freedom of disturbance from 
 atmospheric causes. This is caused by the line being always open except at the instant of the letter 
 being sent ; then if in same direction, can only assist the current from the battery. 
 
 Another new feature is its power of cutting off all offices except those to which it is desired to com- 
 municate. This is accomplished by a flange on the type wheel — this flange having a space cut out 
 opposite a certain letter — each office having the flange cut out at different letters from each other. A 
 bolt is made to slide through this space, and moved through by the action of the instrument. If this 
 bolt is sent through at the moment the space is opposite, it permits the instrument to run ; if not, it 
 goes against the flange and locks the wheel. 
 
 The success of telegraphs for overland communications soon turned the attention to its practicability 
 as a submarine conductor. As early as in August 1843, Prof. S. F. B. Morse, in a letter to the Secre- 
 tary of the Treasury of the United States, speaking of an experiment which he made the previous year, 
 of passing an electric current through a submerged conductor, says : the inference from this law is that 
 a telegraphic communication may with certainty be established across the- Atlantic. In the autumn of 
 1842, he submerged an insulated wire from the Battery to Governor’s Island, and had just begun to 
 operate, having received but two or three characters, when the wire was raised and broken by being 
 drawn up with the anchor of a vessel. He also succeeded in transmitting a current across a stream or 
 canal, by means of parallel lines along the banks. 
 
 In the fall of 1850, a wire of about the size of an ordinary knitting needle encased in a coating of gutta 
 percha, was laid from Calais to Dover ; communications were transmitted for a time through this wire, 
 but soon a portion became broken, and another cable was laid composed of four copper wires, each insu 
 lated with gutta percha, and afterwards bound together with hemp steeped in a solution of tar and tallow. 
 
 In May, 1852, Holyhead and Howth, a distance of 65 miles across the Irish Channel, were connected 
 by a single wire encased in gutta percha. Scotland and Ireland were connected by a cable of thirty 
 miles long consisting of six wires. 
 
 The following June a cable was laid from Orfordness, in England, to the Hague in Holland, a distance 
 of 115 miles. This task was accomplished in thirty-four hours, and only 44 miles of cable were re- 
 quired in the paying out over the actual length from point to point, making hardly 120 miles altogether 
 Another cable connects Dover with Ostend, making the third between England and the continent. 
 
 In the summer of 1854 a telegraphic union was effected between Corsica and Sardinia. This work 
 was attended with much difficulty in consequence of the breaking of a part of the wire. The submerg- 
 ng of a cable between Corsica and the island of Sardinia was successfully accomplished shortly after - 
 
TELEGRAPH. 
 
 701 
 
 but the attempt which was subsequently made to connect the island of Sardinia and Algeria, and thus 
 establish immediate communication between the continents of Europe and Africa, was unsuccessful, and 
 bas not since been attempted. 
 
 The New York, Newfoundland and London Telegraph Company made. an attempt in August of 1855, 
 to unite the islands of Newfoundland and Cape Breton, but the vessels employed in the work were 
 caught in a gale, the cable was obliged to be cut, and the undertaking abandoned for that time. The 
 cable, as may be seen from the accompanying engravings, which show the exact size, had three con- 
 ductors, and was protected in the same manner, by iron wire, as those already described. 
 
 3402. In 1856 the company succeeded in making the desired connection be- 
 
 tween the opposite shores of Newfoundland and Cape Breton. This time they 
 rejected the three wire cable and procured a much lighter one, with a single 
 wire, consisting of seven strands. The object of this arrangement, instead of 
 a single wire of the same thickness, is to provide against the 
 possibility of any break of continuity taking place in the 
 metal. This strand will stretch twenty per cent, of its own 
 length, and is covered with three layers of the purest gutta 
 t jpercha, separately applied. The cable weighs somewhat 
 sinless than a ton to the mile, and is one of the lightest and 
 strongest of its thickness yet manuactured. 
 
 A few weeks after the allied army entered the ( ’rimea 
 a single wire cable was laid across the Black Sea, a dis- 
 tance of 374 miles, between Varna and Balaklava, and it was through this that the English and French 
 governments were apprised every day of the movements of the belligerent forces on either side. This 
 is the longest submarine cable which has yet been laid. 
 
 In the fall of 1857, an attempt was made to lay a cable between Valentia Bay, Ireland, and St. Johns, 
 Newfoundland, a distance of 1650 miles. The attempt was unsuccessful, the cable having parted after 
 some 300 and odd miles had been laid. It will be again undertaken this year, and it is to be hoped 
 with better success. 
 
 From the following engravings it will be seen that the transatlantic submarine cable is somemhat dif- 
 ferently made from any previously manufactured. The core, or conductor, is composed like that of the 
 
 gulf cable, of seven cop- 
 per wires wound together 
 in the same manner. The 
 cable will be 2,500 miles 
 in length, the surplus 
 over the actual distance 
 to be traversed being 
 considered necessary in 
 
 case of emergency to make up for the inequalities in the bed of the ocean, and the variations that may 
 be caused by the winds and the currents. The protecting wires are made into strands, each composed of 
 seven of the best charcoal iron wires. The aggregate length of the smaller wires required in the manu- 
 facture of one mile of the cable is one hundred and twenty-six miles, and the whole cable will require 
 three hundred and fifteen thousand miles of this wire. 
 
 The flexibility of this cable is so great that it can be made as manageable as a small rope, and it is- 
 capable of being tied around the arm without injury. Its weight is but 1,800 pounds to the mile, and 
 its strength such that it will bear in water over six miles of its own length if suspended vertically. 
 
 3404. 
 
 3403. 
 
 Table of Submarine Cables already laid down. 
 
 Miles. 
 
 From Dover to Calais, . . . 21 
 
 From Ilowth to Holyhead, . . .65 
 
 Between Ireland and Scotland, . . 20 
 
 From England to Holland, . . .115 
 
 From Dover to Ostend, ... 60 
 
 From Balaklava to Varna, Black Sea, . 374 
 Between Sardinia on the main land, and 
 
 Corsica, 60 
 
 Total miles now laid, 
 
 Miles. 
 
 Between Corsica and the Island, of Sar- 
 dinia, ...... G 
 
 Across the Gulf of St. Lawrence, from 
 
 Cape Breton to Newfoundland, . 74 
 
 Across the straits of Northumberland, be- 
 tween Cape Tormentine and Prince 
 Edward’s Island, . . .101 
 
 805 ^ 
 
 The application of the telegraph to comparative astronomical observations is a splendid result of the 
 iperations of the American Coast Survey. The transit of a star over the meridian of two places, con- 
 nected by telegraph, was notified from one to the other by a touch of the signal-key, and the time at eacli 
 was observed. The longitude could be thus obtained, with some precautions, with an ease and accu- 
 racy not before possible. A second step was then taken, by connecting the chronometer, which was the 
 standard of time, directly with the telegraph. Thus the seconds-wheel was made, by Dr. Locke, to 
 raise a little platinum hammer, by which the circuit of the telegraph was broken once a second. By 
 another invention, the pendulum swept through a little globule of mercury when at its centre of oscil- 
 lation, thus completing the circuit once a second. The fillet of paper of the telegraph, as it unwound 
 from its spool, at the extreme, and also at the intermediate stations of the line, was thus graduated 
 accurately into seconds, represented by a line with a short break, or a break with a short line. A 
 signal-key was also included in the circuit, by which the observer could complete or break the circuil 
 
702 
 
 TELESCOPE. 
 
 momentarily so as to mark upon the same fillet the transit of the star over the wire of the telescope. 
 A permanent and incomparably accurate record was thus made of the observation, and the instant of its 
 time. It is estimated that the facilities of astronomical observation are increased sixty-fold by this in- 
 vention. In fact, it -constitutes an era in modern astronomy. Though the work of the last one or twc 
 years, it has already received the tribute of the most distinguished foreign observers. 
 
 TELESCOPE. An optical instrument for viewing distant objects. 
 
 For several reasons a distant object is seen less distinctly than a similar near one. The angle which 
 an object subtends diminishes as the distance increases ; the density of the light which renders it visible 
 also diminishes with the distance, but in a much faster ratio; and a considerable portion of light is al- 
 ways lost in its passage through the atmosphere. 
 
 It is found by experience that to be discernible at all in ordinary daylight, a detached object must 
 subtend at the eye an angle of not less that 30", and that the least angle under which contiguous ob- 
 jects can be satisfactorily distinguished is about one minute. By the aid of a telescope a magnified 
 image of the object is obtained ; and within certain limits the object is not only apparently enlarged, 
 nut rendered brighter than it appears to the unassisted eye. 
 
 The invention of the telescope, to which practical astronomy is indebted for its most important dis- 
 coveries, has been ascribed to various persons. Sir David Brewster ( Encyc . Brit., art. “ Optics”) says 
 “ We have no doubt that this invaluable instrument was invented by Roger Bacon or Baptista Porta, in 
 the form of an experiment ; though it had not, perhaps, in their hands assumed the maturity of an in- 
 strument made for sale, and applied to useful purposes, both terrestrial and celestial. If a telescope is 
 an instrument by means of which things at a distance can be seen better than by the naked eye, then 
 Baptista Porta’s concave lens was a real telescope ; but if we give the name to a tube having a convex 
 object-glass at one end, and a convex or concave lens at the other, placed at the distance of the sum or 
 difference of their focal lengths, then we have no distinct evidence that such an instrument was used be- 
 fore the beginning of the 17th century.” Descartes ascribes the invention to James Metius, a citizen of 
 Alkmaer in Holland ; Huygens to John Lippersey, or Zacharias Jansen ; Borellus also to Jansen. Pro- 
 fessor Moll, who has discussed these rival claims, after examining the official papers preserved in the 
 archives at the Hague, comes to the conclusion that Metius (whose proper name was Jacob Adriaansy,) 
 on the 17th of October, 1608, was in possession of the art of making telescopes, but that from some un- 
 explained reason he concealed his invention, and thus gave up every claim to the honor he would have 
 derived from it ; that on the 21st of October in the same year, 1608, John or Hans Lippersey, a spectacle- 
 maker of Middleburg, was actually in possession of the invention; and that there is little reason to be- 
 lieve that either Hans or Zacharias Zanz (or Jansen, father and son) were inventors of the telescope, 
 though one of them invented a compound microscope about 1590. (, Journal of the Royal Institu- 
 
 tion, vol. i.) 
 
 The telescope soon made its way into other countries. In April or May, 1609, the illustrious Galileo, 
 having heard a rumor of the invention, set about considering the means whereby distant objects could 
 be seen distinctly, and was soon in possession of a telescope which magnified three times. In subse- 
 quent trials he succeeded in increasing the magnifying power; and before the beginning of 1610 he had 
 observed the satellites of Jupiter. In England, Harriot also, in 1609, began to use the telescope 
 for examining the disk of the moon, and before he had heard of the discoveries of Galileo. ( Priestley's 
 History of Discoveries relating to Vision, Light, and Colors .) 
 
 Telescopes are of two kinds, refracting and reflecting telescopes: the former depending on the use of 
 properly figured lenses, through which the rays of light pass ; and the latter on the use of specula, or 
 polished metallic mirrors, which reflect the rays ; an inverted image of the object being formed in both 
 cases in the focus of the lens or mirror. 
 
 Refracting telescopes were those which were first constructed. They were of the most simple char- 
 acter, consisting merely of an object-glass of one lens, and an eye-glass of one lens, but of a shorter 
 focus. But in this construction the prismatic colors produced by the difference of the refrangibility of 
 the luminous rays tinged the images of all objects seen through the telescope, and the image was like- 
 wise distorted by the aberration of the extreme rays. It was soon found that the latter defect could 
 be sufficiently corrected by employing more lenses than one in the eye-piece ; but it was long before a 
 remedy was found for the chromatic dispersion ; and artists, despairing of success, generally turned 
 their attention to the improvement of instruments of the reflecting class. The difficulty, however, was 
 at length overcome through the persevering efforts of John Dolland, (see Achromatism ;) and the achro- 
 matic refracting telescope may now be regarded as an instrument all but perfect. 
 
 The general aim in the construction of a telescope is to form, by means of lenses or mirrors, as large, 
 bright, and distinct an image of a distant object as possible, and then to view the image with a magnify- 
 ing glass in any convenient manner. We shall first describe those of the refracting glass. 
 
 Galilean telescope. — This is the most ancient form of the telescope, and is that which was used by 
 Galileo. It consists of a converging object-glass AB, Fig. 3402, and a concave diverging eye-glass C D 
 On passing through the object-glass A B the rays 
 
 of light coming from the different points of a dis- 3402 - 
 
 tant object in jjarallel pencils are rendered con- A 
 
 vergent, and proceed towards the principal focus, 
 where they would form an inverted image ; but 
 before they arrive at this point they fall upon the 
 concave lens C D, by which they are again rendered 
 parallel, or at least their convergence is corrected 
 so as to give distinct vision of the object to the eye 
 at E. The lens C D is therefore placed between the object-glass and the image, and at a distance from 
 the image equal to its principal focal distance. The magnifying power is equal to the princiDal focal 
 distance of the object-glass. Seo Lens. 
 
TELESCOPE. 
 
 708 
 
 In this telescope the object is seen erect, and the length of the tube is only the difference between 
 the focal lengths of the two lenses. These properties render it preferable to any other telescope for 
 many ordinary purposes ; as, for example, an opera-glass. When used for this purpose the magnifying 
 power is hardly ever greater than 4 ; and it is often as low as 2. 
 
 Astronomical telescope . — This is composed of a converging object-glass A B, Fig. 3403, and of a con- 
 verging eye-glass C D. Rays of light proceeding from any point M of a distant object M 1S T , and falling 
 on the different points of the object-glass, are refracted into a point m in the principal focus. In like 
 manner, those proceeding from the point N are 
 
 refracted into the point n ; and thus an invert- 3403. 
 
 ed image rn n is formed at the focus of the ob- c , M 
 
 ject-glass. The eye-glass is placed so that its 
 focus shall coincide with the place of the im- 
 age ; consequently rays diverging from any 
 point of the image, and falling on the lens 
 O D, are refracted into a joarallel direction be- 
 fore they enter the eye at E, and are thereby 
 rendered fit to produce distinct vision. The length of the telescope is equal to the sum of the focal dis- 
 tances of the two lenses; and the magnifying power is equal to the focal distance of the object-glass 
 divided by the focal distance of the eye-glass. This telescope was first described by Kepler in his 
 Rioptrice, 1611 ; but it does not appear to have been executed until about twenty or thirty years 
 later. 
 
 Terrestrial telescope . — This differs from the astronomical telescope only in having two additional 
 lenses E F, G H, Fig. 3404, placed in the tube of the eye-glass for the purpose of restoring the inverted 
 image to its erect position, and thereby accommodating the telescope to terrestrial objects. The focal 
 lengths of these additional lenses are usually the same as that of the eye-glass. The two pencils of 
 rays proceeding from the points M and N cross each other in the anterior focus of the second lens E F, 
 and falling parallel on E F form in its principal focus an inverted image of m n, and consequently an 
 erect image of the object M N. This image m' n’ is seen by the eye at E through the lens GH, as the 
 rays diverging from m' and n' in the focus of G H enter the eye in parallel pencils. When the three 
 first lenses are equal, the magnifying power is the same as that of the astronomical telescope, whose 
 object and eye glasses are the same as A B and C D. 
 
 3404 . 
 
 The performance of refracting telescopes depends most essentially on the goodness of the object-glass , 
 for if the first image is bright and distinct, and perfectly achromatic, there is little difficulty in construct- 
 ing eye-pieces to magnify it, without causing it to undergo any sensible alteration. 
 
 Reflecting telescopes . — In reflecting telescopes the speculum, or mirror, performs the same office that 
 the object-glass does in those of the refracting kind, and is therefore called the object-mirror. The in- 
 strument is constructed in various forms ; but these differ from one another chiefly in reference to the 
 contrivances which have been adopted for bringing the focal image into a convenient situation for being 
 viewed by the eye-piece. The principal forms are the Newtonian, the Gregorian, the Cassegrainian, and 
 the Herschelian. 
 
 Newtonian telescope . — Let ABCD, Fig. 3405, represent a section of the tube of the telescope ; A B the 
 object-mirror, which would form at its focus the image a of any distant object. Now if a person at- 
 tempted to view the image in its place at a by placing himself directly before the mirror, he would ne- 
 cessarily intercept the rays of light from the object passing down the tube to the mirror, and conse- 
 quently there would be no image to view. Sir Isaac Newton overcame this difficulty by introducing a 
 small diagonal plane speculum d between A B and a, which intercepting itself but a small portion of 
 
 
 light, reflects towards the side of the tube the rays converging from A B, and causes the image which 
 would have been formed at a to be formed at b, where it can be conveniently viewed by the eye-piece 
 E attached to the side of the tube. The small mirror is of an oval form, and is fixed on a slender arm 
 c connected with a slide, by means of which it may be made to approach or recede from the large spec- 
 ulum A B, according as the image approaches to or recedes from it. In this telescope the magnifying 
 power is equal to the focal length of the object-mirror A B divided by that of the eye-glass- 
 
704 
 
 TELESCOPE. 
 
 Gregorian telescope. — In this construction the object-mirror A B, Fig. 3406, is perforated in the mid- 
 dle, and the rays of light from a distant object being reflected from the surface of A B cross each other 
 in the focus, where they form an inverted image a, and are then intercepted by a small concave mirror 
 d, which causes them again to converge to a focus at b, near the perforation of the object-mirror, where 
 they form a reinverted or direct image, which is viewed by an eye-piece E screwed into the tube behind 
 AB. The curvature of the small speculum should be elliptical, having the foci at a and i> ; but it is 
 generally made spherical,. In this case the great speculum should be slightly hyperbolic, to counteract 
 the aberration of the small mirror. 
 
 Cassegrainian telescope. — The great speculum of this instrument. is perforated like the Gregorian ; but 
 the rays converging from the surface of the mirror AB, Fig. 3407, towards the, focus a, are intercepted 
 before they reach that point by a small convex mirror d, not sufficiently convex to make the rays diver- 
 gent, but of such a curvature as to prevent them from coming to a focus till they are thrown back to b, 
 near the aperture in A B, where they form an inverted image which is viewed by the eye-piece E. This 
 construction has the advantage of requiring a shorter tube than the Gregorian ; but the inversion of the 
 image is not corrected, and for this reason probably it has not been much used. 
 
 In the two last constructions the small mirror d is adjusted by means of a rod turning on a shoulder 
 near the eye end of the tube, and connected by a screw with the apparatus which carries the arm c, to 
 which the mirror is attached. 
 
 3 - 107 . 
 
 3108 . 
 
 D 
 
 Herschelian telescope . — This construction differs from the others in having no second mirror. The 
 large speculum A B, Fig. 3408, is placed at the bottom of the tube in an inclined position, so as to bring 
 the focal image a near the edge of the tube, where it is viewed directly by the eye-piece F without in- 
 terfering with the light entering the telescope from the object observed. The magnifying power is the 
 same as in the Newtonian. 
 
 The reflecting telescope was invented by James Gregory, and is described by him in his Optica Pro- 
 mota, 1663 ; but the first telescope of the kind was executed by Newton. P^eflecting telescopes have 
 been made on a very large scale. The celebrated instrument of Sir William Herschel, erected at Slough 
 in 1789, was 40 feet in length. Its great speculum had a diameter of 49^ inches ; its thickness was 
 about 3-J- inches, and its weight when cast was 2118 lbs. Its focal length was 40 feet, and it admitted 
 of a power of 6450 being applied to it. The essential advantage of large telescopes of this kind consists 
 in the immense quantity of light which they collect, whereby the observer is enabled to perceive faint 
 nebulae and stars which are altogether invisible in ordinary instruments. 
 
 Reflecting telescopes are used only for observing phenomena , and are not like refracting telescopes, 
 attached to circular instruments for the purpose of measuring angles with greater precision. In order 
 to derive full benefit from them they must be used in the open air ; and must either be mounted equa- 
 torially, (see Equatorial ;) or else in such a manner as to be capable of a smooth motion both in a ver- 
 tical and horizontal direction. Telescopes of this kind being generally used with a high magnifying 
 power, and consequently having a small field of view, are always accompanied with a smaller telescope 
 or finder fixed to the tube, so that the axes of the two inst ruments are exactly parallel. 
 
 Eye-pieces of telescopes.— When the image formed by the object-glass or mirror is viewed with a sin- 
 gle lens or eye-glass, whether concave or convex, it is only in the centre of the field that distinct vision 
 is obtained, all towards the margin being hazy and distorted. To remedy this defect, Boscovich and 
 Huygens separately proposed the construction of an eye-piece formed of two lenses, placed at a distance 
 from each other equal to half their focal distances. Boscovich recommended two similar lenses ; Huy- 
 gens, that the focal length of the one should be twice that of the other ; and as this construction is found 
 to answer best in practice, it is that which is most commonly used. 
 
 The two lenses are usually plano-convex, with the convex faces towards the object-glass ; the larger 
 lens, called the field glass, is innermost, or nearest the object-glass ; and a diaphragm cutting off the 
 marginal rays is usually placed between them near the focus of the eye-lens, where the image is formed. 
 This eye-piece is usually called the negative eye-piece, from its having the image seen by the eye be- 
 hind the field glass ; and is that which is commonly supplied with telescopes intended only for the pur- 
 pose of seeing objects without reference to measurement. 
 
 Another modification of the two-lens eye-piece was proposed by Ramsden, and is called the pjositive 
 eye-piece, because the image observed is before both lenses. The lenses are plano-convex, and nearly 
 of the same focal length ; but their distance from each other is less than the focal distance of the lens 
 nearest the eye, two lenses thus placed acting as a compound simple lens. This eye-piece is the most 
 convenient when micrometer wires are placed in the focus, because it can be taken out without injuring 
 the wires ; and it has also this advantage, that the measure of an object given by one eye-piece is not 
 altered when it is changed for another of a different magnifying power. 
 
 In both the eye-pieces now described, the image is seen inverted ; and though this is of no import 
 
TEMPERING METALS, ETC. 
 
 705 
 
 ance in astronomical observations, it is inconvenient when the telescope is used for looking at terrestrial 
 objects. By placing an additional pair of lenses in the tube of the eye-piece, the image is repeated and 
 reinverted, and, consequently, seen erect. By this means, as explained above, the terrestrial telescope 
 is obtained. 
 
 The name of diagonal eye-piece has been given to eye-pieces furnished with a diagonal reflecting mir- 
 ror, tlie object of which is to give a more convenient direction to the rays emerging from tire eye-piece 
 when the telescope is pointed high. 
 
 Telescopes are generally supplied with eye-pieces of different powers, which are all fitted to enter the 
 same tube ; and the focal adjustment is commonly effected by a rack and pinion motion acting on the 
 tube which carries the eye-piece. 
 
 TEMPERING, HARDENING, AND SOFTENING METALS used in the mechanical and useful 
 arts . — When the malleable metals are hammered, or rolled, they generally increase in hardness, in 
 elasticity^, and in density or specific gravity, which effects are produced simply from the closer approxi- 
 mation of their particles ; and in this respect steel may be perhaps considered to excel, as the process 
 called hammer-hardening, which simply means hammering without heat, is frequently employed as the 
 sole means of hardening some kinds of steel springs, and for which it answers remarkably welL 
 
 After a certain degree of compression, the malleable metals assume their closest and most condensed 
 states ; and it then becomes necessary to discontinue the compression or elongation, as it would cause 
 the disunion or cracking of the sheet or wire, or else the metal must be softened by the process of an- 
 nealing. 
 
 The metals, lead, tin, and zinc, are by some considered to be perceptibly softened by immersion in 
 boiling water ; but such of the metals as will bear it are generally heated to redness, the cohesion of 
 the mass is for the time reduced, and the metal becomes as soft as at first, and the working and an- 
 nealing may be thus alternately pursued, until the sheet metal, or the wire, reaches its limit of tenuity. 
 
 The generality of the metals and alloys suffer no very observable change, whether or not they are 
 suddenly quenched in water from the red-heat. Pure hammered iron, like the rest, appears after an- 
 nealing to be equally soft, whether suddenly or slowly cooled ; some of the impure kinds of malleable 
 iron harden by immersion, but only to an extent that is rather hurtful than useful, and which may be 
 considered as an accidental quality. 
 
 Steel however receives by sudden cooling that extreme degree of hardness combined with tenacity, 
 which places it so incalculably beyond every other material for the manufacture of cutting tools ; espe- 
 cially as it likewise admits of a regular gradation from extreme hardness to its softest state, when sub- 
 sequently reheated or tempered. Steel therefore assumes a place in the economy of manufactures 
 Unapproachable by any other material ; consequently we may safely say that without it, it would be 
 impossible to produce nearly all our finished works in metal and other hard substances ; for although 
 some of the metallic alloys are remarkable for hardness, and were used for various implements of peace- 
 ful industry, and also those of war, before the invention of steel, yet in point of absolute aDd enduring 
 hardness, and equally so in respect to elasticity and tenacity, they fall exceedingly short of hardened 
 steel. 
 
 Hammer-hardening renders the steel more fibrous and less crystalline, and reduces it -in bulk; on the 
 other hand, fire-hardening makes steel more crystalline, and frequently of greater bulk ; but the elastic 
 nature of hammer-hardened steel will not take so wide nor so efficient a range as that which is fire- 
 hardened. 
 
 If we attempt to seek the remarkable difference between pure iron and steel in their chemical analy- 
 ses, it appears to result from a minute portion of carbon ; and cast-iron, which possesses a much larger 
 share, presents, as we should expect, somewhat similar phenomena. 
 
 Iron semi-steelified contains one 150th of carbon. 
 
 Soft cast-steel capable of welding “ 120th 
 
 Cast-steel for common purposes “ 100th 
 
 Cast-steel requiring more hardness “ 90th 
 
 Steel capable of standing a few blows, but quite unfit for drawing “ 50th 
 
 First approach to a steely granulated fracture “ 30th to 40th 
 
 White cast-iron “ 25th 
 
 Mottled cast-iron “ 20th 
 
 Carbonated cast-iron “ 15th 
 
 Super-carbonated crude iron , “ 12th 
 
 Moreover, as the hard and soft conditions of steel may be reversed backwards and forwards without 
 any rapid chemical change in its substance, it has been pronounced to result from internal arrangement 
 or crystallization, which may be in a degree, illustrated and explained by similar changes observed 
 in glass. 
 
 A wine-glass, or other object recently blown, and plunged whilst red-hot into cold water, cracks in a 
 thousand places, and even cooled in warm air it is very brittle, and will scarcely endure the slightest 
 violence or sudden change of temperature ; and visitors to the glass-house are often shown that a wine- 
 glass or other article of irregular form, breaks in cooling in the open air from its unequal contraction at 
 different parts. But the objects would have become useful, and less disposed to fracture, if they had 
 been allowed to arrange their particles gradually, during their very slow passage through the long an- 
 nealing oven or leer of the glass-house, the end at which they enter being at the red-heat, and the op- 
 posite extremity almost cold 
 
 To perfect the annealing, it is not unusual with lamp-glasses, tubes for steam-gages, and similar 
 pieces exposed to sudden transitions of heat and cold, to place them in a vessel of cold water, which is 
 slowly raised to the boiling temperature, kept for some hours at that heat, and then allowed to cool 
 very slowly : the effect thus produced is far from chimerical. For such pieces of flint-glass intended 
 Von. II.— 45 
 
TEMPERING METALS, ETC. 
 
 700 
 
 for cutting as are found to be insufficiently annealed, the boiling is sometimes preferred to a spcond 
 passage through the leer : lamp-glasses are also much less exposed to fracture when they have been 
 once used, as the heat if not too suddenly applied or checked, completes the annealing. 
 
 Steel in like manner when suddenly cooled is disposed to crack in pieces, which is a constant source 
 ol anxiety ; the danger increases with the thickness in the same way as with glass, and the more espe- 
 cially when the works are unequally thick and thin. 
 
 Another ground of analogy between glass and steel, appears to exist in the pieces of unannealed 
 glass used for exhibiting the phenomena, formerly called double refraction, but now polarization of 
 light; an effect distinctly traced to its peculiar crystalline structure. 
 
 In glass it is supposed to arise from the cooling of the external crust more rapidly than the internal 
 mass ; the outer crust is therefore in a state of tension, or restraint, from an attempt to squeeze the 
 inner mass into a smaller space than it seems to require ; and from the hasty arrangement of the unan- 
 nealed glass, the natural positions of its crystals are in a measure disturbed or dislocated. 
 
 It has been shown experimentally, that a rearrangement of the particles of glass occurs in the pro- 
 cess of annealing, as of two pieces of the same tube each 40 inches long, the one sent through the leer, 
 contracted one-sixteenth of an inch more than the other, which was cooled as usual in the open air. 
 'lubes for philosophical purposes are not annealed, as their inner surfaces are apt to become soiled with 
 the sulphur of the fuel ; they are in consequence very brittle and liable to accident. 
 
 In the philosophical toy, the Prince Rupert’s drop, this disruption is curiously evident to the sight, as 
 the inner substance is cracked and divided into a multitude of detached parts, held together by the 
 smooth external coat. The unannealed glass, when cautiously heated and slowly cooled, ceases to 
 present the polarizing effect, and the steel similarly treated ceases to be hard, and may we not there- 
 fore indulge in the speculation, that in both cases a peculiar crystalline structure is consequent upon 
 the unannealed or hardened state ? 
 
 In the process of hardening steel, water is by no means essential, as the sole object is to extract its 
 heat rapidly ; and the following are examples, commencing with the condition of extreme hardness, and 
 ending with the reverse condition. 
 
 A thin heated blade placed between the cold hammer and anvil, or other good conductors of heat, 
 becomes perfectly hard. Thicker pieces of steel, cooled by exposure to the air upon the anvil, become 
 rather hard, but readily admit of being filed. They become softer when placed on the cold cinders, or 
 other bad conductors of heat. Still more soft when placed in hot cinders, or within the fire itself, and 
 cooled by their gradual extinction. When the steel is incased in close boxes with charcoal powder, and 
 it is raised to a red-heat and allowed to cool in the fire or furnace, it assumes its softest state ; unless 
 lastly, we proceed to its partial decomposition. This is done by inclosing the steel with iron turnings 
 or filings, the scales from the smith’s anvil, lime, or other matters that will abstract the carbon from its 
 surface ; by this mode it is superficially decarbonized, or reduced to the condition of pure soft iron, in 
 the manner practised by Mr. Jacob Perkins, in his most ingenious and effective combination of pro- 
 cesses, employed for producing, in unlimited numbers, absolutely identical impressions of bank notes 
 and checks, for the prevention of forgery. 
 
 A nearly similar variety of conditions might be referred to as existing in cast-iron in its ordinary 
 state, governed by the magnitude, quality, and management of the castings ; independently of which, 
 by one particular method, some cast-iron may be rendered externally as hard as the hardest steel: 
 such are called chilled-iron castings ; and, as the opposite extreme, by a method of annealing combined 
 with partial decomposition, malleable-iron castings may be obtained, so that cast-iron nails may be 
 clenched. 
 
 Again, the purest iron, and most varieties of cast-iron, may, by another proceeding, be superficially 
 converted into steel, and then hardened, the operation being appropriately named case-hardening. 
 
 It may perhaps be truly said, that upon no one subject connected with mechanical art does there 
 exist such a contrariety of opinion, not unmixed with prejudice, as upon that of hardening and temper- 
 ing steel ; which makes it often difficult to reconcile the practices followed by different individuals in 
 order to arrive at exactly similar ends. The real difficulty of the subject occurs in part from the mys- 
 teriousness of the change ; and from the absence of defined measures, by which either the steps of the 
 pirocess itself, or the value of the results when obtained, may be satisfactorily measured ; as each is de- 
 termined almost alone by the unassisted senses of sight and touch, instead of by those physical means 
 by which numerous other matters may be strictly tested and measured, nearly without reference to the 
 judgment of the individual, yhieh in its very nature is less to be relied upon. 
 
 The excellence of cutting-tools, for instance, is pronounced upon their relative degrees of endurance, 
 but many accidental circumstances here interfere to vitiate the strict comparison : and in respect to the 
 measure of simple hardness, nearly the only test is the resistance the objects offer to the file, a mode in 
 two ways defective, as the files differ among themselves in hardness ; and they only serve to indicate 
 in an imperfect manner to the touch of the individual, a general notion without any distinct measure, 
 so that when the opinion of half a dozen persons may be taken, upon as many pieces of steel differing 
 hut slightly in hardness, the want of uniformity in their decisions will show the vague nature of the proof 
 
 Under these circumstances, instead of recommending any particular methods, we have determined to 
 advance a variety of practical examples derived from various sources, which will serve in most cases to 
 confirm, but in some to confute one another ; leaving to every individual to follow those examples which 
 may be the most nearly parallel with his own wants. There are, however, some few points upon which 
 it may be said that all are agreed ; namely, 
 
 The temperature suitable to forging and hardening steel differs in some degree with its quality and 
 its mode of manufacture ■ the heat that is required diminishes with the increase of carbon : 
 
 In every case the loxeest available temperature should be employed in each process, the hammering 
 should be applied in the most equal manner throughout, and for cutting tools it should be continued 
 mtil they ar - nearly cold : 
 
TEMPERING METALS, ETC. 
 
 TOT 
 
 Coke or charcoal is much better as a fuel than fresh coal, the sulphur of which is highly injurious : 
 
 The scale should be removed from the face of the work to expose it the more uniformly to the effect 
 of the cooling medium : 
 
 Hardening a second time without the intervention of hammering is attended with increased risk; and 
 the less frequently steel passes through the fire the better. 
 
 In hardening and tempering steel there are three things to be considered ; namely, the means of 
 heating the objects to redness, the means of cooling the same, and the means of applying the heat for 
 tempering or letting them down. I will speak of these separately, before giving examples of their 
 application. 
 
 The smallest works are heated with the flame of the blowpipe and are occasionally supported upon 
 charcoal. (See Soldering.) 
 
 For objects that are too large to be heated by the blowpipe, and too small to be conveniently warmed 
 in the naked fire, various protective means are employed. Thus an iron tube or sheet-iron box inserted 
 in the midst of the ignited fuel is a safe and cleanly way ; it resembles the muffle employed in chemi- 
 cal works. The work is then managed with long forceps made of steel or iron wire, bent in the form 
 of the letter U, and flattened or hollowed at the ends. A crucible or an iron pot about four to six 
 inches deejy filled with lead and heated to redness, is likewise excellent, but more particularly for long 
 and thin tools, such as gravers for artists, and other slight instruments ; several of these may be inserted 
 at once, although towards the last they should be moved about to equalize the heat ; the weight of the 
 lead make9 it desirable to use a bridle or trevet for the support of the crucible. Some workmen place 
 on the fire a pan of charcoal dust, and heat it to redness. 
 
 Great numbers of tools, both of medium and large size, are heated in the ordinary forge fire, which 
 should consist of cinders rather than fresh coals : coke and also charcoal are used, but far less generally ; 
 recourse is also had to hollow fires ; but the bellows should be very sparingly used, except in blowing 
 up the fire before the introduction of the work, which should be allowed ample time to get hot, or, as it is 
 called, to “ soak.” 
 
 It is a common and excellent practice among some workmen to use coke both in forging and harden- 
 ing steel goods. They frequently prepare it for themselves, either upon the forge-hearth or in a heap 
 in the open yard. 
 
 Which method soever may be resorted to for heating the work, the greatest care should be given to 
 communicate to all the parts requiring to be hardened a uniform temperature, and which is only to be 
 arrived at by cautiously moving the work to and fro to expose all parts alike to the fire ; the difficulty 
 of accomplishing this of course increases with long objects, for which fires of proportionate length are 
 required. 
 
 It is far better to err on the side of deficiency than of excess of heat ; the point is rather critical, and 
 not alike in all varieties of steel. Until the quality of the steel is familiarly known, it is a safe precau- 
 tion to commence rather too low than otherwise, as then the extent of the mischief will be the neces- 
 sity for a repetition of the process at a higher degree of heat ; but the steel if burned or overheated 
 will be covered with scales, and what is far worse, its quality will be permanently iujured ; a good 
 hammering will, in a degree, restore it ; but this in finished works is generally impracticable. 
 
 It is argued by some, that by heating pieces of steel to different degrees, before plunging them into 
 the water, the one piece attains full hardness, the next the temper of a tool fit for metal, another of a 
 tool fit for wood, a fourth that of a spring, and so on; That this view is not altogether without founda- 
 tion, appears in the fact that if the end of a piece of steel be made entirely hard, the transition is not 
 quite immediate from the hard to the soft part; in making points, such as are used in a dividing-engine, 
 it is customary to harden the end of a longer piece of steel than is required, and form the point upon 
 the grindstone, exactly at that part where the temper suits, without the steel being let down at all. In 
 hardening by this method, however, without tempering, the scale of proper hardness is confined within 
 such extremely narrow limits, as to be nearly useless ; thus, it frequently happens that in a number of 
 tools heated as nearly alike as the workman could judge, some few will be found too soft for any use, 
 although they were all intended to receive the ordinary hardness, so as to require letting down, as usual 
 with those tools exposed to violent strains or blows, such as screw-taps, cold chisels, and hatchets, 
 although many tools for metal, used with quiet and uniform pressure, are left of the full hardness for 
 'greater durability. 
 
 With the excess of heat, beyond tlie lowest that vr.ll suffice, the brittleness rather than the useful hard- 
 ness of tools is increased ; and when no excess of heat is employed beyond that absolutely requisite for 
 hardening in the usual manner, the steel does not appear to be injured, and the colors on its brightened 
 surface that occur in tempering are an excellent, and in general, sufficiently trustworthy index of the 
 inferior degrees of hardness proper for various uses. 
 
 Less than a certain heat fails to produce hardness, and in the opinion of some workmen has quite the 
 opposite effect, and they consequently resort to it as the means of rapid annealing, not, however, by 
 plunging the steel into the water and allowing it to remain until cold, but dipping it quickly, holding 
 it in the steam for a few moments, dipping it again, and so on, reducing it to the cold state in a hasty 
 but intermittent manner. 
 
 There is another opinion prevalent among workmen, that steel which is “pinny” or as if composed 
 of a bundle of hard wires, is rendered uniform in its substance if it is first hardened and then an- 
 nealed. 
 
 Secondly, the choice of the cooling medium has reference mainly to the relative powers of conducting 
 heat they severally possess: the following have been at different times resorted to with various degrees 
 of success: currents of cold air; immersion in water in various states, in oil or wax, and in freezing 
 mixtures ; mercury, and flat metallic surfaces have been also used. Mr. Perkins recommended, as the 
 result of his experiments, plain water at a temperature of 40° Fahrenheit. On the whole, however, 
 there appears to be an opinion that mercury gives the greatest degree of hardness; then cold salt ano 
 
708 
 
 TEMPERING METALS, ETC. 
 
 water, or water mixed with various ‘"astringent and acidifying matters;” plain water follows; and 
 lastly, oily mixtures. 
 
 I find but one person who has commonly used the mercury ; many presume upon the good conduct- 
 ing power of the metal, and the nonformation of steam, which causes a separation betwixt the steel and 
 water when the latter is employed as the cooling medium. I have failed to learn the reason of the ad- 
 vantage of salt and water, unless the fluid have, as well as a greater density, a superior conducting 
 power. The file-makers medicate the water in other ways, but this is one of the questionable myste- 
 ries which is never divulged ; although it is supposed that a small quantity of white arsenic is gener- 
 ally added to water saturated with salt. One thing however may be noticed, that articles hardened in 
 salt and water are apt to rust, unless they are laid for a time in lime-water, or some neutralizing agent. 
 
 With plain water an opinion very largely exists in favor of that which has been used over and over 
 again even for years, provided it is not greasy : and when the steel is very harsh, the chill is taken off 
 plain water to lessen the risk of cracking it ; oily mixtures impart to thin articles, such as springs, a 
 sufficient and milder degree of hardness, with less danger of cracking, than from water ; and in some 
 cases a medium course is pursued by covering the water with a thick film of oil, which is said to be 
 adopted occasionally with scythes, reaping-hooks, and thin edge-tools. 
 
 From experiments upon all these means, we are induced fully to acquiesce in Mr. Perkins’ recom- 
 mendation of plain cold water for general purposes ; except in the case of thin elastic works, for which 
 oil, or oily compositions are certainly more proper. 
 
 A so-called natural spring is made by a vessel with a true and a false bottom, the latter perforated 
 with small holes ; it is filled with water, and a copious supply is admitted beneath the partition ; it 
 ascends through the holes, and pursues the same current as the heated portions, which also escape at 
 the top. This was invented by the late Jacob Perkins, and was used by him in hardening the rollers 
 for transferring the impressions to the steel-plates for bank notes. 
 
 Sometimes when neighboring parts of works are required to be respectively hard and soft, metal 
 tubes or collars- are fitted tight upon the work, to protect the parts to be kejrt soft from the direct ac- 
 tion of the water, at any rate for so long a period as they retain the temperature suitable to hardening. 
 
 The process of hardening is generally one of anxiety, as the sudden transition from heat to cold often 
 causes the works to become greatly distorted if not cracked. The last accident is much the most likely 
 to occur with thick massive pieces, which are as it were hardened in layers, as although the external 
 crust or shell may be perfectly hard, there is almost a certainty that towards the centre the parts are 
 gradually less hard ; and when broken the inner portions will sometimes admit of being readily filed. 
 
 When in the fire the steel becomes altogether expanded, and in the water its outer crust is suddenly 
 arrested, but with a tendency to contract from the loss of heat, which cannot so rapidly occur at the 
 central part ; it may be therefore presumed that the inner bulk continues to contract after the outer 
 crust is fixed, and which tends to tear the two asunder, the more especially if there be any defective 
 part in the steel itself. An external flake of greater or less extent not unfrequently shells off in har- 
 dening; and it often happens that works remain unbroken for hours after removed from the water, but 
 eventually give w T ay and crack with a loud report, from the rigid unequal tension produced by the vio- 
 lence of the process of hardening. 
 
 The contiguity of thick and thin parts is also highly dangerous, as they can neither receive, nor yield 
 up heat, in the same times ; the mischief is sometimes lessened by binding pieces of metal around the 
 thin parts with wire, to save them from the action of the cooling medium. Sharp angular notches are 
 also fertile sources of mischief, and, where practicable, they should be rejected in favor of curved lines. 
 
 As regards both cracks and distortions, it may perhaps be generally said, that their avoidance de- 
 pends principally upon manipulation , or the successful management of every step : first the original 
 manufacture of the steel, its being forged and wrought, so that it may be equally condensed on all 
 sides with the hammer, otherwise when the cohesion of the mass is lessened from its becoming red-hot, 
 it recovers in part from any unequal state of density in which it may have been placed. 
 
 While red-hot, it is also in its weakest condition ; it is therefore prone to injury either from incautious 
 handling with the tongs, or from meeting the sudden cooling action irregularly, and therefore it is gen- 
 erally best to plunge works vertically, as all parts are then exposed to equal circumstances, and less 
 disturbance is risked than when the objects are immersed obliquely or sideways into the water ; al- 
 though for swords, and objects of similar form, it is found the best to dip them exactly as in making a 
 vertical downward cut with a sabre, which for this weapon is its strongest direction. 
 
 Occasionally objects are clamped between stubborn pieces of metal, as soft iron or copper, during 
 their passage through the fire and water. Such plans can be seldom adopted and are rarely followed, 
 the success of the process being mostly allowed to depend exclusively upon good general management. 
 
 In recent experiments in making the magnets for dipping-needles, which are about ten inches long, 
 one-fourth of an inch wide, and the two-hundredth part of an inch thick, this precaution entirely failed ; 
 and the needles assumed all sorts of distortions when released from between the stiff bars within which 
 they were hardened. The plan was eventually abandoned, and the magnets were heated in the ordi- 
 nary way within an iron tube, and were set straight with the hammer after being let down to a deep 
 orange or brown color. Steel however is in the best condition for the formation of good permanent 
 magnets when perfectly hard. 
 
 In all cases the thick unequal scale left from the forge should be ground off before hardening, in 
 order to expose a clean metallic surface, otherwise the cooling medium cannot produce its due and 
 equal effect throughout the instrument. The edges also should be left thick, that they may not be 
 burned in the fire ; thus it will frequent.lv happen that the extreme end or edge of a tool is inferior in 
 quality to the part within, and that the instrument is much better after it has been a few times 
 ground : 
 
 “ He that, -will a good Edge win 
 Must Forge thick and Grind thin.” 
 
TEMPERING METALS, ETC. 
 
 70', 
 
 Thirdly, the heat for tempering or letting down. Between the extreme conditions of hard and soft 
 steel there are many intermediate grades, the common index for which is the oxidation of the brightened 
 surface, and it is quite sufficient for practice. These tints, and their respective approximate tempera- 
 tures, are thus tabulated : 
 
 1. Very pale straw yellow 
 
 2. A shade of darker yellow 
 
 3. Darker straw yellow 
 
 4. Still darker straw yellow 
 
 5. A brown yellow 
 
 6. A yellow, tinged slightly with purple. 
 
 7. Light purple 
 
 8. Dark purple 
 
 9. Dark blue 
 
 10. Paler blue 
 
 11. Still paler blue 
 
 12. Still paler blue, with a tinge of green 
 
 410 | Tools for metal. 
 
 470 ) Tools for wood, and screw-taps, 
 490 \ &c. 
 
 500 i Hatchets, chipping-chisels, and 
 520 >• other percussive tools, saws, 
 530 ) &c. 
 
 550 / c • 
 
 -,_ A 1 Springs. 
 o,0 J 1 ° 
 
 590 1 
 
 610 > Too soft for the above purposes. 
 630 ) 
 
 The first tint arrives at about 430° F., but it is only seen by comparison with a piece of steel not 
 heated : the tempering colors differ slightly with the various qualities of steel. 
 
 The knife-edges, for Cajotain Eater’s experimental pendulum, were very carefully hardened and tem- 
 pered in a bath heated to 430° ; being then found too soft they were rehardened, and tempered, at only 
 the heat of boiling water, after which they were considered admirably suited to their purpose. 
 
 The heat for tempering being moderate, it is often supplied by the part of the tool not requiring to 
 be hardened, and which is not therefore cooled in the water. The workman first hastily tries with a 
 file whether the work is hard, he then partially brightens it at a few parts with a piece of grindstone 
 or an emery stick, that he may be enabled to watch for the required color ; which attained, the work 
 is usually cooled in any convenient manner, lest the body of the tool should continue to supply heat. 
 But when, on the contrary, the color does not otherwise appear, partial recurrence is had to the mode 
 in which the work was heated, as the flame of the candle, or the surface of the clear fire applied, if 
 possible, a little below the part where the color is to be observed, that it may not be soiled by the 
 smoke. 
 
 A very convenient and general manner of tempering small objects, is to heat to redness a few inches 
 of the end of a flat bar of iron about two feet long; it is laid across the anvil, or fixed by its cold ex- 
 tremity in the vice ; and the work is placed on that part of its surface which is found by trial to be of 
 the suitable temperature, by gradually sliding the work towards the heated extremity. In this manner 
 many tools may be tempered at once, those at the hot part being pushed off into a vessel of water or 
 oil, as they severally show the required color, but it requires dexterity and quickness in thus managing 
 many pieces. 
 
 Vessels containing oil or fusible alloys carefully heated to the required temperatures have also been 
 used, and I shall have to describe a method called “ blazing off’" resorted to for many articles, such as 
 springs and saws, by heating them over the naked fire until the oil, wax, or composition in wdiich they 
 have been hardened ignites ; this can only occur wheu they respectively reach their boiling tempera- 
 tures and are evaporated in the gaseous form. 
 
 The period of letting down the works is also commonly chosen for correcting, by means of the ham- 
 mer, those distortions which so commonly occur in hardening ; this is done upon the anvil, either with 
 the thin pane of an ordinary hammer, or else with a hack-hammer, a tool terminating at each end in an 
 obtuse chisel-edge, which requires continual repair on the grindstone. 
 
 The blows are given on the hollow side of the work, and at right angles to the length of the curve ; 
 they elongate the concave side, and gradually restore it to a plane surface, when the blows are dis- 
 tributed consistently with the positions of the erroneous parts. The hack-hammer unavoidably injures 
 the surface of the work, but the blows should not be violent, as they are then also more prone to break 
 the work, the liability to which is materially lessened when it is kept at or near the tempering heat, 
 and the edge of the hack-hammer is slightly rounded. 
 
 Watchmakers’ drills of the smallest kinds, are heated in the blue part of the flame of the candle; 
 larger drills are heated with the blowpipe flame, applied very obliquely, and a little below the point ; 
 when very thin they may be whisked in the air to cool them, but they are more generally thrust into 
 the tallow of the candle or the oil of the lamp ; they are tempered either by their own heat, or by im- 
 mersion in the flame below the point of the tool. 
 
 For tooLs between those suited to the action of the blowpipe, and those proper for the open fire, there 
 are many which require either the iron tube, or the bath of lead or charcoal ; but the greater number 
 of works are hardened in the ordinary smith’s fire, without such defences. 
 
 Tools of moderate size, such as the majority of turning tools, carpenters’ chisels and gouges, and so 
 forth, are generally heated in the open fire ; they require to be continually drawn backwards and for- 
 wards through the fire, to equalize the temperature applied : they are plunged vertically into the water, 
 and then moved about sideways to expose them to the cooler portions of the fluid. If needful, they 
 are only dipped to a certain depth, the remainder being left soft. 
 
 Some persons use a shallow vessel filled only to the height of the portion to be hardened, and plunge 
 the tools to the bottom ; but this strict line of demarcation is sometimes dangerous, as the tools are ajjt 
 to become cracked at the part, and therefore a small vertical movement is also generally given, that 
 the transition from the hard to the soft part may occupy more length. 
 
 ■Razors and penknives are too frequently hardened without the removal of the scale arising from the 
 forging; this practice which, is not done with the best works, cannot be too much deprecated. The blades 
 are heated in a coke or charcoal fire, and dipped into the water obliquely. In tempering razors, they 
 
710 
 
 TEMPERING METALS, ETC. 
 
 are laid on their backs upon a clear fire, about half-a-dozen together, and they are removed one at a 
 time, "when the edges, ■which are as yet thick, come down to a pale straw-color ; should the backs acci 
 dentally get heated beyond the straw-color, the blades are cooled in water, but not otherwise. Pen 
 knife blades are tempered, a dozen or two at a time, on a plate of iron or copper, about twelve inches 
 long, three or four wide, and about a quarter of an inch thick ; the blades are arranged close together 
 on their backs, and lean at an angle against each other. As they come down to the temper, they are 
 picked out with small pliers and thrown into water, if necessary ; other blades are then thrust forward 
 from the cooler parts of the plate to take their place. 
 
 Hatchets, adzes, cold chisels, and numbers of similar tools, in which the total bulk is considerable 
 compared with the part to be hardened, are only partially dipped ; they are afterwards let down by 
 the heat of the remainder of the tool, and when the color indicative of the temper is attained, they are 
 entirely quenched. With the view of removing the loose scales, or the oxidation acquired in the fire, 
 some workmen rub the objects hastily in dry salt before plunging them in the water, in order to give 
 them a cleaner and whiter face. 
 
 In hardening large dies, anvils, and other pieces of considerable size, by direct immersion, the rapid 
 formation of steam at the sides of the metal prevents the free access of the water for the removal of 
 the heat with the required expedition ; in these cases, a copious stream of water from a reservoir above 
 is allowed to fall on the surface to be hardened. This contrivance is frequently called a “ float,” and 
 although the derivation of the name is not very clear, the practice is excellent, as it supplies an abun- 
 dance of cold water ; and which, as it falls directly on the centre of the anvil, is sure to render that part 
 hard. It is, however, rather dangerous to stand near such works at the time, as when the anvil face is 
 not perfectly welded, it sometimes in part flies off with great violence and a loud report. 
 
 Occasionally the object is partly immersed in a tank beneath the fall of water, by means of a crane 
 and slings ; it is ultimately tempered with its own heat, and dropped in the water to become entirely 
 cold. 
 
 Oil, or various mixtures of oil, tallow, wax, and resin, are used for many thin and elastic objects, such 
 as needles, fish-hooks, steel pens and springs, which require a milder degree of hardness than is given 
 by water. 
 
 For example, steel pens are heated in large quantities in iron trays within a furnace, and are then 
 hardened in an oily mixture ; generally they are likewise tempered in oil, or a composition the boiling 
 point of which is the same as the temperature suited to letting them down. This mode is particularly 
 expeditious, as the temper cannot fall below the assigned degree. The dry heat of an oven is also 
 used, and both the oil and oven may be made to serve for tempers harder than that given by boiling 
 oil ; but more care and observation are required for these lower temperatures. 
 
 Saws and springs are generally hardened in various compositions of oil, suet, wax, and other ingre- 
 dients. The composition used by an experienced saw-maker is two pounds of suet and a quarter of a 
 1 ound of bees- w 7 ax to every gallon of whale-oil ; these are boiled together, and will serve for thin works 
 and most kinds of steel. The addition of black resin, to the extent of about one pound to the gallon, 
 makes it serve for thicker pieces and for those it refused to harden before ; but the resin should be 
 added with judgment, or the works will become too hard and brittle. The composition is useless 
 when it has been constantly employed for about a month : the period depends, however, on the extent 
 to which it is used, and the trough should be thoroughly cleaned out before new mixture is placed in it. 
 
 The following recipe is recommended by an experienced workman : “ Twenty gallons of spermaceti 
 oil ; twenty pounds of beef suet rendered ; one gallon of neats-foot oil ; one pound of pitch ; three 
 pounds of black resin. These tw 7 o last articles must be previously melted together, and then added to 
 the other ingredients ; w 7 hen the whole must be heated in a proper iron vessel, with a close cover fitted 
 to it, until the moisture is entirely evaporated, and the composition will take fire on a flaming body 
 being presented to its surface, but which must be instantly extinguished again by putting on the cover 
 of the vessel.” 
 
 The above ingredients lose their hardening property after a few weeks’ constant use. The saws are 
 heated in long furnaces, and then immersed horizontally and edgeways in a long trough containing the 
 composition ; two troughs are commonly used, the one until it gets too warm, then the other for a pe- 
 riod, and so on alternately. Part of the composition is wiped off the saws with a piece of leather, when 
 they are removed from the trough, and they are heated one by one over a clear coke fire, until the 
 grease inflames ; this is called “ blazing off.” When the saws are wanted to be rather hard, but little 
 of the grease is burned off; when milder, a larger portion ; and for a spring temper, the whole is allowed 
 to burn away. When the work is thick, or irregularly thick and thin, as in some springs, a second and 
 third dose is burned off, to insure equality of temper at all parts alike. 
 
 Gun-lock springs are sometimes literally fried in oil for a considerable time over a fire in an iron 
 tray ; the thick parts are then sure to be sufficiently reduced, and the thin parts do not become the 
 more softened from the continuance of the blazing heat. 
 
 Springs and saws appear to lose their elasticity, after hardening and tempering, from the reduction 
 and friction they undergo in grinding and polishing. Towards the conclusion of the manufacture, the 
 elasticity of the saw is restored principally by hammering, and partly by heating it over a clear coke 
 fire to a straw-color : the tint is removed by very diluted muriatic acid, after which the saws are well 
 washed in plain w 7 ater and dried. 
 
 Watch-springs are hammered out of round steel wire, of suitable diameter, until they fill the gage 
 for width, which at the same time insures equality of thickness ; the holes are punched in their ex- 
 tremities, and they are trimmed on the edge with a smooth file; the springs are then tied up with 
 binding-wire, in a loose open coil, and heated over a charcoal fire upon a perforated revolving-plate, 
 they are hardened in oil, and blazed off. 
 
 The spring is now distended in a long metal frame, similar to that used for a saw-blade, and ground 
 end polished with emery and oil, between lead blocks; by this time its elasticity appears quite Iosl, 
 
TEMPERING METALS, ETC. 
 
 71] 
 
 and it may be bent in any direction ; its elasticity is, however, entirely restored by a subsequent ham 
 mering on a very bright anvil, which u puts the nature into the spring .” 
 
 The coloring is done over a flat plate of iron, or hood, under which a little spirit lamp is kept burning; 
 the spring is continually drawn backwards and forwards, about two or three inches at a time, until it 
 assumes the orange or deep-blue tint throughout, according to the taste of the purchaser ; by many the 
 coloring is considered to be a matter of ornamant, and not essential. The last process is to coiL the 
 spring into the spiral form, that it may enter the barrel in which it is to be contained ; this is done by a 
 tool with a small axis and winch-handle, and does not require heat. 
 
 The balance-springs of marine chronometers, which are in the form of a screw, are wound into the 
 square thread of a screw of the appropriate diameter and coarseness ; the two ends of the spring are 
 retained by side-screws, and the whole is carefully enveloped in platinum foil, and tightly bound with 
 wire. The mass is next heated in a piece of gun-barrel closed at the one end, and plunged into oil, 
 which hardens the spring almost without discoloring it, owing to the exclusion of the air by the close 
 platinum covering, which is now removed, and the spring is let down to the blue, before removal from 
 the screwed block. 
 
 The balance or hair springs of common watches are frequently left soft ; those of the best watches 
 are hardened in the coil upon a plain cylinder, and are then curled into the spiral form between the 
 edge of a blunt knife and the thumb, the same as in curling up a narrow riband of paper, or the fila- 
 ments of an ostrich feather. 
 
 Mr. Dent says that 3200 balance-springs weigh only one ounce ; but springs also include the heaviest 
 examples of hardened-steel works uncombined with iron ; for example, of Mr. Adams’ patent bow- 
 springs for all kinds of vehicles, some intended for railway use, measure 3-1 feet long, and weigh 50 
 pounds each piece ; two of these are used in combination : other single sjirings are 6 feet long, and weigh 
 70 pounds. 
 
 In hardening them they are heated by being drawn backwards and forwards through an ordinary 
 forge-fire, built hollow, and they are immersed in a trough of plain water : in tempering them they are 
 heated until the black-red is just visible at night; by daylight the heat is denoted by its making a piece 
 of wood sparkle when rubbed on the spring, which is then allowed to cool in the air. The metal is 
 9-16ths of an inch thick, and Mr. Adams considers 5-8ths the limit to which steel will harden properly 
 — that is, sufficiently alike to serve as a spring : he tests their elasticity far beyond their intended range. 
 
 Great diversity of opinion exists respecting the cause of elasticity in springs : by some it is referr d 
 to different states of electricity ; by others the elasticity is considered to reside in the thin, blue, oxidized 
 surface, the removal of which is thought to destroy the elasticity, much in the same manner that the 
 elasticity of a cane is greatly lost by stripping off its siliceous rind. The elasticity of a thick spring is 
 certainly much impaired by grinding off a small quantity of its exterior metal, which is harder than the 
 inner portion ; and perhaps thin springs sustain in the polishing a proportional loss, which is to them 
 equally fatal. 
 
 It has been found experimentally that the bare removal of the blue tint from a pendulum spring, by 
 its immersion in weak acid, caused the chronometer to lose nearly one minute each hour ; a second and 
 equal immersion scarcely caused any further loss. It is also stated as a well-known fact that such 
 springs get stronger, in a minute degree, during the first two or three years they are in use, from some 
 atmospheric change ; when the springs are coated with gold by the electrotype process, no such change 
 is observable, and the covering, although perfect, may be so thin as not to compensate for the loss of 
 the blue oxidized surface. 
 
 One of the most serious evils in hardening steel, especially in thick blocks, or those which are un- 
 equally thick and thin, is their liability to crack, from the sudden transition ; and in reference to hard- 
 ening razors, a case in point, Mr. Stodart mentions it as the observation and practice of one of his work- 
 men, “ that the charcoal fire should be made up with shavings of leather and upon being asked what 
 good he supposed the leather could do, this workman replied, “that he could take upon him to say that 
 he never had a razor crack in the hardening since he had used this method, though it was a frequent 
 occurrence before.” 
 
 When brittle substances crack in cooling, it always happens from the outside contracting and becom- 
 ing too small to contain the interior parts. But it is known that hard steel occupies more space than 
 when soft; and it may easily be inferred that the nearer the steel approaches to the state of iron, the 
 less will be this increase of dimensions. If, then, we suppose a razor or any other piece of steel to be 
 heated in an open fire with a current of air passing through it, the external part will, by the loss of 
 carbon, become less steely than before ; and when the whole piece comes to be hardened, the inside 
 will be too large for the external part, which will probably crack. But if the piece of steel be wrapped 
 up in the cementing mixture, or if the fire itself contain animal coal, and is put together so as to operate 
 in the manner of that mixture, the external part, instead of being degraded by this heat, will be more 
 carbonated than the internal part, in consequence of which it will be so far from splitting or bursting 
 during its cooling, that it will be acted upon in a contrary direction, tending to render it more dense 
 and solid. 
 
 The cracking which so often occurs on the immersion of steel articles in water, does not appear to 
 arise so much from any decarbonization of the surface merely, as from the sudden condensation and 
 contraction of a superficial portion of the metal, while the mass inside remains swelled with heat, and 
 probably expands for a moment on the outside coming in contact with the water. 
 
 The file-makers, to save their works from clinking, or cracking partly through in hardening, draw the 
 files through yeast, beer-grounds, or any sticky material, and then through a mixture of common salt 
 and animal hoof roasted and pounded. This is corroborative of the above, as in the like manner it sup- 
 plies a little carbon to the outside, and also renders the steel somewhat harder and less disposed to 
 crack ; the composition also renders the more important service of protecting the fine points of the teeth 
 from beintr injured by the five. 
 
712 
 
 TEMPERING METALS, ETC. 
 
 An analogous method is now practised in hardening patent axletrees which are of wrought-iron, with 
 two pieces of steel welded into the lower side where they rest upon the wheels and sustain the load 
 The work is heated in an open forge-fire, quite in the ordinary way, and when it is removed a mixture, 
 principally the prussiate of potash, is laid upon the steel ; the axletree is then immediately immersed 
 in water, and additional water is allowed to fall upon it from a cistern. The steel is considered to be- 
 come very materially harder for the treatment, and the iron around the same is also partially hardened 
 
 These are, in fact, applications of the case-hardening process, which is usually applied to wrought- 
 iron for giving it a steely exterior, as the name very properly implies. Occasionally steel which hardens 
 hut imperfectly, either from an original defect in the material, or from its having become deteriorated 
 by bad treatment, or too frequent passage through the fire, is submitted to the case-hardenitag process 
 in the ordinary way, by inclosing the objects in iron boxes, as will be explained. This in part restores 
 the carbon which has been lost, and the steel admits of being hardened ; but this practice is not to be 
 generally recommended, although it is well employed for, the purposes of transfer engraving, explained 
 at Engraving on Steel, a method introduced by Mr. Jacob Perkins, and which took its origin in the 
 curious transfer processes of the calico- works, wherein, however, copper is the material principally used. 
 
 Various methods have been likewise attempted to prevent the distortions to which work is liable in 
 the operation of hardening, but without any very advantageous results : for instance, it has been rec- 
 ommended to harden small cylindrical wires by rolling them when heated between cold metallic sur- 
 faces to retain them perfectly straight. This might probably answer, but unfortunately cylindrical steel 
 wires supply but a very insignificant portion of our wants. 
 
 Another mode tried by Dr. Wollaston was to inclose the piece of steel in a tube filled with Newton’s 
 fusible alloy, the whole to be heated to redness and plunged in cold water; the object was released by 
 immersion in boiling water, which melted the alloy, and the piece came out perfectly unaltered in form, 
 and quite hard. This mode is too circuitous for common practice, and the reason why it is to be always 
 successful is not very apparent. 
 
 Mr. Perkins resorted to a very simple practice with the view of lessening the distortion of his en- 
 graved steel plates, by boiling the water in which they were to be hardened to drive off the air, and 
 plunging them vertically ; and as the plates were required to be tempered to a straw color, instead ol 
 allowing them to remain in the water until entirely cold, he removed them whilst the inside was still 
 hot, and placed them on the top of a clear fire until the tallow with which they were rubbed smoked ; 
 the plate was then returned to the water for a few moments, and so on alternately until they were quite 
 cold, the surface never being allowed to exceed the tempering heat. 
 
 From various observations, it appears on the whole to be the best in thick works thus to combine the 
 hardening and tempering processes, instead of allowing the objects to become entirely cold, and then to 
 reheat them for tempering. To ascertain the time when the plate should be first removed from the 
 water, Mr. Perkins heated a piece of steel to the straw color, and dipped it into water to learn the sound 
 it made ; and when the hardened plate caused the same sound, it was considered to be cooled Ic the 
 right degree, and was immediately withdrawn. 
 
 Locomotive wheels with hardened-steel tires may be viewed as the most ponderous example of hard- 
 ening, as the tires of the eight-foot wheels weigh about 10 cwt., and consist of about one-third steel, and 
 there seems no reason why this diameter might not be greatly exceeded. 
 
 The materials for the tires are first swaged separately, and then welded together under the heavy 
 hammer at the steel-works, after which they are bent to the circle, welded, and turned to certain gages. 
 The tire is now heated to redness in a circular furnace ; during the time it is getting hot the iron wheel, 
 previously turned to the right diameter, is bolted down upon a face-plate ; the tire expands with the 
 heat, and when at a cherry-red it is dropped over the wheel, for which it was previously too small, and 
 is also hastily bolted down to the surface-plate, the whole load is quickly immersed by a swing-crane 
 into a tank of water about five feet deep, and hauled up and down until nearly cold ; the steel tires are 
 not afterwards tempered. 
 
 Hardening and softening cast-iron . — The similitude of chemical constitution between steel, which 
 usually contains about one per cent, of carbon, and cast-iron, that has from three to six or seven per 
 cent., naturally leads to the expectation of some correspondence in their characters, and which is found 
 to exist. Thus some kinds of cast-iron will harden almost like steel, but they generally require a higher 
 temperature ; and the majority of cast-iron, also like steel, assumes different degrees of hardness, ac- 
 cording to the rapidity with which the pieces are allowed to cool. 
 
 The casting left undisturbed in the mould, is softer than a similar one exposed to the air soon after it 
 has been poured. Large castings cannot cool very hastily, and are seldom so hard as the small pieces, 
 some of which are hardened like steel by the moisture combined with the moulding sand, and cannot be 
 filed until they have been annealed after the manner of steel, which renders them soft and easy to be 
 worked. 
 
 Chilled iron castings present as difficult a problem as the hardening and tempering of steel ; the fact 
 is simply this, that iron castings, made in iron moulds under particular circumstances, become on their 
 outer surfaces perfectly hard, and resist the file almost like hardened steel ; the effect is, however, su- 
 perficial, as the chilled exterior shows a distinct line of demarcation when the objects are broken. 
 
 Ploughshares are sometimes cast on this principle ; the under sides and points are hard from the 
 chilling process, and these, from resisting abrasion more than the softer parts, maintain a comparatively 
 thin edge. 
 
 The production of chilled castings is always a matter of some uncertainty, and depends upon the 
 united effect of several causes: the quality of the iron, the thickness of the casting,. the temperature of 
 the iron at the time of pouring, and the condition or temperature of the iron mould, which has a greater 
 effect in “ striking in” when the mould is heated than if quite cold : a very thin stratum of earthy matter 
 will almost entirely obviate the chilling effect. A cold mould does not generally chill so readily as one 
 heated nearly to the extent called “ black-hot;” but the reverse conditions occur with some cast-irrn- 
 
TEMPERING METALS, ETC. 
 
 713 
 
 There is this remarkable difference between cast-iron thus hardened, and steel hardened by pi .inging 
 whilst hot into water : that whereas the latter is softened again by a dull-red heat, the chilled castings, 
 on the contrary, are turned out of the moulds as soon as the metal is set, and are allowed to cool in the 
 air ; yet although the whole is at a bright-red heat, no softening of the chilled part takes place. This 
 material has been employed for punches for red-hot iron ; the punches were fixed in cast-iron sockets, 
 from which they only projected sufficiently to perforate the wheel-tires in the formation of which 
 they were used, and from retaining their hardness they were more efficient than those punches made 
 of steel. 
 
 Chilled castings are also commonly employed for axletree-boxes, and naves of wheels, which are fin- 
 ished by grinding only ; also for cylinders for rolling metal, for the heavy hammers and anvils or stithies 
 for iron-works, the stamp-heads for pounding metallic ores, <fcc. Cannon-balls, as well as ploughshares, 
 are examples of chilled castings ; with the destructive engine the chilling is unimportant, and occurs 
 alone from the method essential to giving the balls the required perfection of form and size. 
 
 Malleable-iron castings are at the opposite extreme of the scale, and are rendered externally soft by 
 the abstraction of their carbon, whereby they are nearly reduced to the condition of pure malleable iron, 
 but without the fibre which is due to the hammering and rolling employed at the forge. 
 
 The malleable-iron castings are made front the rich Pennsylvania iron, and are at first as brittle as 
 glass or hardened steel ; they are inclosed in iron boxes of suitable size, and surrounded with pounded 
 iron-stone, or some of the metallic oxides, as the scales from the iron forge, or with common linte, and 
 various other absorbents of carbon, used either together or separately. The cases, which are sometimes 
 as large as barrels, are luted, rolled into the ovens or furnaces, and submitted to a good heat for about 
 live days, and are then allowed to cool very gradually within the furnaces. 
 
 The time and other circumstances determine the depth of the effect ; thin pieces become malleable 
 entirely through, they are then readily bent, and may be slightly forged ; cast-iron nails and tacks thus 
 treated admit of being clinched, thicker pieces retain a central portion of cast-iron, but in a softened 
 state, and not brittle as at first ; on sawing them through, the skin or coat of soft iron is perfectly dis- 
 tinct from the remainder. 
 
 The mode is particularly useful for thin articles that can be more economically and correctly cast 
 than wrought at the forge, as bridle-bits, snuffers, parts of locks, culinary and other vessels, pokers and 
 tongs, many of which are subsequently case-hardened and polished, as will be explained, but malleable 
 cast-iron should never be used for cutting-tools. 
 
 Case-hardening wrought and cast iron. — The property of hardening is not possessed by pure malleable 
 iron; but we have now to explain a rapid and partial process of cementation, by which wrought-iron is 
 first converted exteriorly into steel, and is subsequently hardened to that particular depth ; leaving the 
 central parts in their original condition of soft fibrous iron. The process is very consistently called case- 
 hardening, and is of great importance in the mechanical arts, as the pieces combine the economy, 
 strength, and internal flexibility of iron, with a thin casing of steel ; which, although admirable as an 
 armor of defence from wear or deterioration as regards the surface, is unfit for the formation of cutting 
 edges or tools, owing to the entire absence of hammering, subsequent to the cementation with the car- 
 bon. Cast-iron obtains in like manner a coating of steel, which surrounds the peculiar shape the metal 
 may have assumed iri the iron-foundry and workshop. 
 
 The principal agents used for case-hardening are animal matters, as the hoofs, horns, bones, and skins 
 of animals ; these are nearly alike in chemical constitution, and they are mostly charred and coarsely 
 pounded ; some persons also mix a little common salt with some of the above ; the works should be sur- 
 rounded on all sides with a layer from half an inch to one inch thick. 
 
 The methods pursued by different individuals do not greatly differ ; for example, the gunsmith inserts 
 the iron-work of the gun-lock in a sheet-iron case in the midst of bone-dust, (often not burned,) the lid of 
 the box is tied on with iron-wire, and the joint is luted with clay ; it is then heated to redness as quickly 
 as possible and retained at that heat from half an hour to an hour, and the contents are quickly im- 
 mersed in cold water. The objects sought are a steely exterior, and a clean surface covered with the 
 pretty mottled tints, apparently caused by oxidation from the partial admission of air. 
 
 Some of the malleable-iron castings, such as snuffers, are case-hardened to admit of a better polish ; 
 it is usually done with burnt bone-dust, and at a dull-red heat ; they remain in the fire about two or 
 three hours, and should be immersed in oil, as it does not render them quite so brittle as when plunged 
 into water. It must be remembered they are sometimes changed throughout their substance into an 
 inferior kind of steel, by a process that should in such instances be called cementation, and not case- 
 hardening, consequently they will not endure violence. 
 
 The mechanician and engineer use horns, hoofs, bone-dust, and leather, and allow the period to extend 
 from two to eight hours, most generally four or five ; sometimes, for its greater penetration, the process 
 is repeated a second time with new carbonaceous materials. Some open the box and immerse the work 
 in water direct from the furnace ; others, with the view to preserve a better surface, allow the box to 
 cool without being opened, and harden the pieces with the open fire as a subsequent operation ; the 
 carbon once added, the work may be annealed and hardened much the same as ordinary steel. 
 
 When the case-hardening is required to terminate at any particular part, as a shoulder, the object is 
 left with a band or projection, the work is allowed to cool without being immersed in water, the band 
 is turned off, and the work when hardened in the open fire is only effected so far as the original ce- 
 mented surface remains. This ingenious method was introduced by Mr. Roberts, who considers the 
 success ot the case-hardening process to depend on the gentle application of the heat ; and that, by 
 proper management not to overheat the work, it may be made to penetrate three-eighths of an inch in 
 lour or five hours. 
 
 A new substance for the case-hardening process, but containing the same elements as those more 
 commonly employed, has of late years been added, namely, the prussiate of potash, (a salt consisting r- 
 two atoms of carbon and one of nitrogen,) which is made from a variety of animal matters. 
 
714 
 
 THERMOMETER. 
 
 It is a new application ■without any change of principle ; the time occupied in this steelifying process 
 is sometimes only minutes, instead of hours and days ; as, for example, when iron is heated in the open 
 fire to a dull red, and the prussiate is either sprinkled upon it or rubbed on in the lump, it is returned 
 to the fire for a few minutes and immersed in water ; but the process is then exceedingly superficial, 
 and it may if needful be limited to any particular part upon which alone the prussiate is applied. The 
 effect by many is thought to be partial or in spots, as if the salt refused to act uniformly, in the same 
 manner that water only moistens a greasy surface in places. 
 
 The prussiate of potash has been used for case-hardening the bearings of wrought-iron shafts, but this 
 seems scarcely worth the doing. It has been also employed with the view of giving an additional and 
 extreme, although superficial hardness to steel, as in axletrees, Perkins’s engraved steel-plates, <tc. ; but 
 we have only heard of one individual who has encased work with this salt — it was for case-hardening 
 the iron rollers and side-plates of glaziers’ vices employed for milling window-lead. 
 
 In the general way, the conversion of the iron into steel by case-hardening is quite superficial, and 
 does not exceed the sixteenth of an inch ; if made to extend to one-quarter or three-eighths of an inch 
 in depth, to say the least, it would be generally useless, as the object is to obtain durability of surface, 
 with strength of interior, and this would disproportionately encroach on the strong iron within. The 
 steel obtained in this adventitious manner is not equal in strength to that converted and hammered in 
 the usual way, and if sent in so deeply, the provision for wear would far exceed that which is required. 
 
 Let us compare the case-hardening process with the usual conversion of steel. The latter requires a 
 period of about seven days, and a very pure carbon, namely, wood charcoal, of which a minute portion 
 only is absorbed ; and it being a simple body, when the access of air is prevented by the proper security 
 of the troughs, the bulk of the charcoal remains unconsumed, and is reserved for future use, as it has 
 undergone no change. The hasty and partial process of cementation is produced in a period commonly 
 less than as many hours with the animal charcoal, or than as many minutes with the prussiate of pot- 
 ash ; but all these, are compound bodies, (which contain cyanogen, a body consisting of carbon and nitro- 
 gen,) and are never used a second time, but on the contrary the process is often repeated with another 
 dose. It would be, therefore, an interesting inquiry for the chemist, as to whether the cyanogen is ab- 
 sorbed after the same manner as carbon in ordinary steel, (and which in Mackintosh’s patent process 
 was driven through the crucible in the form of carbonic acid gas, and is stated to be absorbed at the 
 rate of one-thirtieth of an inch in depth, each hour ;) or whether the nitrogen assists in any way in hast- 
 ening the admission of the carbon, by some as yet untraced affinity or decomposition. 
 
 This hasty supposition will apply less easily to cast-iron, which contains from three to seven times as 
 much carbon as steel, and although not always hardened by simple immersion, is constantly under the 
 influence of the case-hardening process ; unless we adopt the supposition, that the carbon in cast-iron 
 which is mixed with the metal in the shape of cinder in the blast-furnace, when all is in a fluid state, is 
 in a less refined union than that instilled in a more aeriform condition in the acts of cementation and 
 case-hardening. (See Tools.) 
 
 THERMOMETER. An instrument for measuring variations of heat or temperature. The principle 
 upon which thermometers are constructed is the change of volume which takes place in bodies when 
 their temperature undergoes an alteration. Generally speaking, all bodies expand when heated and 
 contract when cooled, and in such a manner that, under the same circumstances of temperature, they re- 
 turn to the same dimensions; so that the change of volume becomes the exponent of the temperature 
 which produces it. But as it is necessary not merely that expansion and contraction take place, but 
 that they be capable of being conveniently observed and measured, only a small number of bodies are 
 adapted for thermometrical purposes. Solid bodies, for example, undergo so small a change of volume 
 with moderate variations of temperature, that they are in general only used for measuring very high 
 temperatures, as the heat of furnaces, of melting metals, <kc. Instruments for such purposes are called 
 pyrometers. (See Pyrometer.) The gaseous fluids, on the other hand, are extremely susceptible ol 
 the impressions of heat and cold ; and as their changes of volume are great even with moderate acces- 
 sions of heat, they are only adapted for indicating very minute variations, or for forming differential 
 thermometers. Liquids hold an intermediate place ; and by reason of their moderate but sensible ex- 
 pansion through the ranges of temperature within which observations have to be made for by far the 
 greater number of purposes, are commonly used for the construction of thermometers. Various liquids 
 have been proposed, as oils, ether, spirits of wine, and mercury ; but scarcely any other than the two 
 last are now ever used, and mercury by far the most generally. 
 
 The properties which render mercury preferable to all other liquids (unless for particular purposes) 
 are these: 1. It supports, before it boils and is reduced to vapor, more heat than any other fluid, ex- 
 cepting certain oils, and endures a greater cold than would congeal most other liquids, excepting certain 
 spirituous liquors. 2. It takes the temperature of the medium in which it is placed more quickly than 
 any other fluid. Count Rumford found that mercury was heated from the freezing to the boiling point 
 of water in 58 seconds, while water took 133 seconds, and air 617 seconds, the heat applied being the 
 same, in all the three cases. 3. The variations of its volume within limits which include the tempera- 
 tures most frequently required to be observed, are found to be perfectly regular, and proportional tc 
 the variations of temperature. The spirit thermometer is now little used excepting for observations oi 
 very low temperatures, or as a self-registering instrument for meteorological observations. 
 
 Construction of the mercurial thermometer . — In order to render small changes of volume sensible, a 
 glass bulb, having a slender hollow tube attached to it, is filled with mercury, so that expansion or con- 
 traction can only take place by the rise or fall of the liquid in the tube. The diameter of the tube may 
 be of any convenient size ; but the smaller it is the larger will be the scale of the variations ; and capil- 
 lary tubes are usually employed. It is essential that the diameter of the bore be of a uniform width 
 throughout ; a quality which is tested by drawing up into the tube a short column of mercury, and 
 measuring its length at the different parts with a pair of compasses. Not more than a sixth part of the 
 tubes which come from the glass-house are found to be fit for the purpose. 
 
THERMOMETER. 
 
 71 , 
 
 Having selected a tube, the workman begins by blowing a hollow ball A, Fig. 3409, upon one extrem- 
 'ty of it, by means of an air-bag of caoutchouc, (in order to avoid the introduction of watery vapor by 
 olowing from the mouth.) The length which the thermometer is to have is then marked, and 
 above this point the tube is expanded into a second bulb B, rather larger than the first. When the 3409 
 tube has acquired its natural temperature one of the bulbs is warmed, in order to expel the air I 
 from it, and the open end of the tube is plunged into distilled and well-boiled mercury. During I 
 the cooling the mercury rises into the second bulb B, whence it is made to pass into A by placing JL._ 
 this undermost, and expelling the air from it by heat, after which the mercury descends from the 
 effect of cooling. When the bulb A has been completely filled, and also a part of B, the tube is 
 suspended horizontally over a charcoal fire, so as to be equally heated throughout, and the in- 
 closed mercury boiled, in order to expel every remaining particle of air or humidity. The open 
 end is then touched with sealing-wax, and the tube withdrawn from the fire, and placed in an up- 
 right position until it is cooled, when the bulb A and the portion of the tube under B will be filled j 
 with mercury. A portion of mercury is then expelled by heat, so that the column may stand at 
 the proper height in the tube. The tube is then carefully softened with the blowpipe, and her- 
 metically sealed under the bulb B, which is thus cut off. 
 
 Graduation of the scale . — The instrument prepared in the manner now described is admirably adapted 
 for rendering evident the expansions and contractions of the inclosed fluid, and it only remains to adopt 
 a scale to it in order to have a complete thermometer. The graduation of the scale is in some measure 
 arbitrary ; nevertheless, in order that different thermometers may be comparable with each other, it is 
 necessary that two points at least be taken on the scale corresponding to fixed and determinate tem- 
 peratures, the distance between which will determine the graduation. The two points which are now 
 universally chosen for this purpose are those which correspond to the temperatures of freezing and boil- 
 ing water. With respect to the first of these there is no difficulty ; it is only necessary to surround the 
 bulb with ice, and to mark on the stem the point at which the mercury stands when the ice begins to 
 melt. The boiling point is not so readily determined. As the temperature at which water boils varies 
 to a small extent with the barometric pressure, it is necessary, in order to have instruments comparable 
 with each other, either that the boiling point on the scale be determined when the barometer stands at 
 a certain height which is arbitrarily assumed for the standard, or else to apply a correction when the 
 actual height of the barometer is above or below the assumed standard. De Luc made a number of 
 experiments on this subject, and gave a formula for the correction, which was adapted to Fahrenheit’s 
 scale and English inches by Horsley. (Phil. Trans., vol. Ixiv.) A committee of the Royal Society who 
 undertook to investigate the best method of adjusting the fixed points, and whose report is contained in 
 vol. lxvii. of the Transactions, laid down a set of rules which have been generally followed by English 
 instrument-makers. They recommended the adoption of 29'8 inches for the standard barometric pres- 
 sure, and gave a table of the corrections for all ordinary pressures above or below this standard. Their 
 table is very nearly represented by the following simple rule, which will be quite sufficient for the guid- 
 ance of the artist in all ordinary cases : 
 
 Supposing the thermometer placed in an atmosphere of steam immediately over the surface of boil- 
 ing water, then for every tenth of an inch by which the barometer is above or below 29'8, the correction 
 for the boiling point of the scale of the thermometer is one-thousandth part of the interval between the 
 freezing and boiling points. The corrected must be placed lower than the observed boiling point by 
 this quantity when the pressure exceeds 29'8 inches, and higher when the pressure is less than the 
 standard. 
 
 Several other minute circumstances must be attended to in the construction of delicate instruments. 
 As the temperature of boiling water is different at the top and near the bottom of the vessel in which 
 it boils, the thermometer should not be plunged into the water itself, but into the vapor which rises 
 above it, in a close vessel with an aperture for the escape of the steam. The vessel should be of metal, 
 because water boils at a different temperature in vessels of different substances, as metal and glass. 
 Distilled water, or clear soft water, should be used ; if mixed with saline ingredients, the temperature 
 at which it boils would be affected, and the instrument rendered inaccurate. 
 
 The interval between the two fixed points on the stem may be divided into any number of degrees 
 at pleasure, and the graduation continued above and below as far as may be thought requisite : the nu- 
 meration may also be begun at any point whatever on the scale ; but there are only three methods of 
 division so generally adopted as to require particular notice. The first is Fahrenheit’s, which is used in 
 England, Holland, and North America ; the second, Reaumer’s, which was formerly in general use in 
 France, and is still followed in Sj>ain and some parts of Germany ; and the third that of Celsius, or the 
 centigrade scale, now used in France, Germany, and Sweden. 
 
 Fahrenheit's scale. — Tn this scale the interval between the freezing and boiling points of water is 
 divided into 180 equal parts or degrees, which number was chosen by Fahrenheit, (or probably Roemer,) 
 from some theoretical ■considerations respecting the expansion of mercury ; it being computed that the 
 thermometer, when plunged into melting snow, contained 11,156 parts of mercury, which, at the tem- 
 perature of boiling water, were expanded into 11,336 parts, being an increase of 180 parts. The zero 
 point of the scale is placed at 32° below the freezing point of water. It has been frequently stated 
 that this point was selected as indicating the temperature of a freezing mixture of snow and salt ; but 
 it appears from Boerhaave that it was adopted from a still more precarious supposition, namely, the 
 greatest cold observed in Iceland, which was probably assumed to be the lowest natural temperature. 
 The freezing point is thus marked 32°, and consequently the boiling point at 32 -f- 180 = 212. It must 
 be admitted that this scale, though it possesses some advantages in the lowness of the zero point and 
 the smallness of the divisions, is not well adapted to philosophical purposes. 
 
 Reaumer's scale . — Reaumer, in 1130, proposed the adoption of the temperature of melting ice as tho 
 r.ero of the scale, and to divide the distance between this and the boiling point of water into 80°, hav- 
 ing observed that between those temperatures spirits of wine (which he used for the thermometric 
 
716 
 
 THERMOMETER. 
 
 fluid) expanded from 1000 parts to 1080. This division soon became general in France and othet 
 countries, and a great number of valuable observations have been recorded in terms of it; but it is now 
 seldom used in works of science. 
 
 Centigrade scale. — In 1742 Celsius, professor at Upsal, in Sweden, proposed to divide the space be- 
 tween the freezing and boiling points of water into 100 equal parts, the zero point being placed (as in 
 Reaumer’s) at freezing. This division being in harmony with our decimal arithmetic, is better adapted 
 than the two former to scientific purposes. It has been adopted by all the French writers since the 
 Revolution, and is the best known in most parts of the north and middle of Europe. 
 
 It has been sometimes objected to this scale, (and the objection applies equally to Reaumer’s,) that 
 on account of the comparatively high point at which the zero is placed, meteorological observations are 
 embarrassed with the algebraic signs of plus and minus. The inconvenience (if any) is a very trifling 
 one, and is much more than compensated by the facilities for calculation which the scale affords. 
 
 Conversion of degrees of one scale into degrees of another. — From the manner in which the three scales 
 are graduated, it is easy to deduce formul* expressing any temperature given according to one scale in 
 terms of either of the others. The interval which in Fahrenheit’s scale is divided into 180 parts is di- 
 vided into only 100 parts in the centigrade scale, and into 80 in Reaumer’s. Hence one degree of Fah- 
 renheit’s is equal to 5-9ths of a degree of the centigrade, and to 4-9ths of a degree of Reaumer. But 
 some attention is required on account of the difference of the zero points. For the sake of perspicuity, 
 it is convenient to adapt the expressions to three distinct cases. Let F denote degrees of Fahrenheit’s 
 scale, C degrees of the centigrade, and R degrees of Reaumer ; then, 
 
 Case I. For all temperatures above the freezing point, 
 
 F — 32 = fC = JR. 
 
 Case 2. For all temperatures between the freezing point and the zero of Fahrenheit’s scale, 
 
 32 — F = — 4 C = — SR. 
 
 Case 3. For all temperatures below the zero of Fahrenheit, 
 
 — 32 — F= — fC= — §R. 
 
 By substituting numbers in these formula? for F, C, or R, as the case may require, the corresponding 
 values on the other scales is immediately obtained ; but if many reductions are required to be made, it 
 is more convenient to have comparative tables, by which the correspondence of the scales is seen at a 
 glance. Such tables are given in most treatises on chemistry. 
 
 Theory of the graduation. — It will be evident from what has now been said that, whatever scale be 
 adopted, the division is founded on the assumed principle that equal increments of heat produce equal 
 expansions. This assumption may be put to the test of experiment by the mixture of fluids at different 
 temperatures. For example, if a pound of water at 212° Fahr. be mixed with another pound of water 
 at 32°, and the requisite precautions be used, then the temperature of the mixture will be 122°, which 
 is the arithmetical mean between the two temperatures ; and if the assumed principle be correct, a ther- 
 mometer plunged into the mixture will stand at 122°. This is found to be the case with the mercurial, 
 but not with the spirit thermometer ; and, in general, thermometers formed of different fluids, when ex- 
 posed to the same temperatures, do not give the same indications throughout the whole extent of the 
 scale. An important question hence arises : what substance ought to be adopted as the standard to 
 which, in comparing observations, all others should be reduced ? It is, perhaps, not possible to deter- 
 mine this question with absolute certainty; but the experiments of the French chemists Dulong and 
 Petit on the dilatation of various substances, render it probable that air and the other permanent gases 
 (which all expand equally) afford the most accurate indications of the true variations of temperature. 
 As compared with the air thermometer, the expansion of mercury is proportional to the increase of tem- 
 perature from — 30° to -f- 100° of the centigrade scale. From this point to 360° (the boiling point of 
 mercury) mercury expands more rapidly than air, and consequently the mercurial thermometer stands 
 higher than the air thermometer in the same temperature. When the former indicates 200° and 300°, 
 the latter indicates 197° and 292'7° respectively ; and it seems to be a general law that all fluids with 
 the same increase of heat expand more rapidly as the temperature approaches their boiling point. The 
 more rapid expansion of the mercury at high temperatures is, however, in some measure corrected by 
 the expansion of the bulb. 
 
 Change of the zero point.- — There is a circumstance connected with the mercurial thermometer which 
 requires to be attended to when very exact determinations of temperature are to be made. Bellani, in 
 Italy, and Flaugergues in France, observed that when thermometers which have been constructed for 
 several years are placed in melting ice, the mercury stands in general higher than the zero point of the 
 scale ; and this circumstance, which renders the scale inaccurate, has been usually ascribed to the slow- 
 ness with which the glass of the bulb acquires its permanent arrangement, after having been heated to 
 a high degree in boiling the mercury. Despretz ( Trcdte de Physique) observes, that in very nice ex- 
 periments it is always necessary to verify the zero point; for he found that when thermometers have 
 been kept during a certain time in a low temperature, the zero point rises, but falls when they have 
 been kept in a high temperature ; and this remark applies equally to old thermometers and to those 
 which have been recently constructed. 
 
 Register thermometers. — In meteorological observations it is of great importance to ascertain the lim 
 its of the range of the thermometer in a given period of time, during a day or night, for example, while 
 the observer is absent. Numerous contrivances have accordingly been proposed for this purpose, but 
 the two following are those most frequently used. 
 
 Six's register thermometer. — This instrument was invented by Mr. Six, of Colchester, England, and is 
 described in the Phil. Trans., vol. lxxii. It is a spirit thermometer, having a long cylindrical bulb A, 
 Fig. 3410, with the tube bent in the form of a siphon, and terminating in a small cavity B. A part of 
 the tube, from a to 6, is filled with mercury ; but the bulb A, and the remaining portion of the tube 
 
THERMOMETER. 
 
 717 
 
 3410. 
 
 
 ■ 1 
 
 and a small part of the cavity 13, with highly rectified alcohol. The use of the mercury in the middle 
 of the tube is to give motion to two indices, c and d, which consist each of a glass tube in which a small 
 bit of iron wire is inclosed, the ends being capped with enamel. The indices are of such a 
 size that they move freely within the barometric tube, and allow the spirit to pass ; but a 
 slender spring is attached to each, which presses against the side of the tube, and is just 
 strong enough to prevent the index from falling down when it has been raised to any point 
 and the mercury recedes. The action of the instrument will be readily apprehended from 
 the figure. An increase of heat expands the alcohol in the bulb A, depresses the mercury 
 at a, and consequently raises it in the other branch of the siphon at b. The mercury while 
 rising drives the index d before it; and when the temperature diminishes, the mercury re- 
 cedes from the index, which is retained in its place by the action of the spring, and conse- 
 quently marks the highest point at which the mercury has stood. In like manner, when 
 the spirit in the bulb A is contracted by a diminution of heat, the mercury is pressed to- 
 wards A by the elastic force of a portion of air purposely left in the cavity B, and drives 
 before it the index c, which is prevented from falling back by the. spring, and consequently 
 remains at the highest point at which the mercury has stood in that branch of the siphon. 
 
 When the observation has been made, the indices are brought- back to the surface of the 
 mercury by means of a magnet, which acts on the inclosed iron wire and overcomes the force of the 
 spring. A scale is applied to each limb of the siphon, and graduated by comparison with a standard 
 thermometer. 
 
 This instrument has all the defects which belong to the spirit thermometer, and the indications arc 
 besides in some degree deranged by the expansion and contraction of the inclosed column of mercury; 
 probably, also, by the friction of the indices. Nevertheless, it is the best instrument we possess for de- 
 termining the temperature of the sea at great depths. 
 
 Rutherford's thermometer. — Another register thermometer, simpler in its construction, and less ex- 
 pensive than the former, and consequently more generally used, is the day and night thermometer pro- 
 posed by Dr. Rutherford in the Edinburgh Transactions, vol. iii. It consists simply of two thermome 
 ters; a mercurial thermometer A, Fig. 3411, and a spirit thermometer B, 
 attached horizontally to the same frame, and each provided with its own 
 scale. The index of A is a bit of steel, which is pushed before the mer- 
 cury ; but, in consequence of its horizontal position, remains in its place 
 when the mercury recedes, and consequently indicates the highest degree 
 of the scale to which the mercury has risen. The index of B is of glass, 
 with a small knob at each end. This lies in the spirit, which freely 
 passes it when the thermometer rises ; but when the spir it recedes, the cohesive attraction between the 
 fluid and the glass overcomes the friction arising from the weight of the index, and the index is conse- 
 quently carried back with the spirit towards the bulb. As there is no force to move it in the opposite 
 direction, it remains at the point nearest the bulb to which it has been brought, and thus indicates the 
 lowest temperature which has occurred. By inclining the instrument the indices are brought to the 
 surfaces of their respective fluids, and prepared for a new observation. 
 
 History of the thermometer . — The invention of the thermometer dates from about the beginning of 
 the 17th century, but it is not certainly known when or by whom it was first brought into use. By the 
 Dutch authors it is ascribed to Cornelius Drebbel, a peasant of Alkmaar, and by the Italians to Sanc- 
 torio. Libri ( Annates de Chitnie, Dec. 1830) maintains, on the authority of Castelli and Viviani, that ' 
 the instrument was invented by Galileo prior to-1597. The thermometer of Drebbel and Sanctorio was 
 a very imperfect instrument. It consisted of a glass tube, having a ball blown on one of its extremi- 
 ties, and the other end left open. A portion of air being expelled from the ball by heat, the open end 
 was plunged into a cup containing any liquid, when, on the cooling of the ball, the liquid would rise in 
 the tube, and the variations of its height indicate the increase or diminution of the temperature of the 
 bulb. The instrument had no scale, and was therefore merely an indicator of changes of temperature, 
 or a thermoscope ; and it was defective even in this respect, inasmuch as it is affected not merely by 
 heat and cold, but by the varying pressure of the atmosphere. The Florentine academicians first ex- 
 cluded the influence of atmospheric pressure by using a spirit instead of an air thermometer, and her- 
 metically sealing the tube. The next step in improvement was the adoption of a fixed point in the 
 scale. Boyle proposed the thawing oil of aniseeds, which he preferred to thawing ice, because it could 
 be readily obtained at all times of the year. Halley proposed the uniform temperature of a deep pit, 
 which he probably considered would be the mean temperature of the earth ; but he also suggested the 
 point at which spirit boils as well as the boiling point of water. Newton appears to have been the first 
 who saw the advantage of having two fixed points in the scale ; and in order that the instrument might 
 be applicable to a wider range of temperature, he used linseed oil as the thermometric fluid. This, 
 however, has not been found to answer, on account of its sluggish motion and adhesion to the sides of 
 the tube. The astronomer Roemer proposed the substitution of mercury, which is now generally used ; 
 and the knowledge of the fluctuation of the boiling point of water, owing to atmospheric pressure, is 
 due to Fahrenheit, about 1724. Since that time no improvement has been made in the principle of the 
 instrument. 
 
 For further information on this subject the reader may be referred to Deluc, Recherches sur les Modi- 
 fications de V Atmosphere, Geneve, 1772; Biot, Traite de Physique, tome 1 ; Nicholson's Chemistry; 
 Library of Usef ul Knowledge, “ Thermometer and Pyrometer ;” Muncke in Gehler's Physicalisckes 
 1 Vorterbuch. 
 
 Saxton's Deep Sea Thermometer. In conducting the off-shore hydrography of the United States Coast 
 Survey, the proximity of the Gulf Stream, and its important bearings on the chief highways of our 
 commerce, have made it specially incumbent on the Coast Survey organization to develop the great 
 physical features of this phenomenon with as much accuracy as possible. The exigency of the work of 
 
718 
 
 THERMOMETER. 
 
 sounding along the shore has hitherto withheld the organization from any full investigation of the Gulf 
 Stream problems, yet several results of much interest, as to its form, position, movements, and tempe- 
 ratures, have been already reached in more or less detail. How to observe the deep sea temperatures 
 which are ever disturbing the rest of the ocean — how to bring up, from a depth of several miles, a trust- 
 worthy reading of the heat which prevails in those unexplored recesses, is a question which demands an 
 answer before the Gulf Stream can be fully comprehended in its fundamental facts. 
 
 The proposed investigations were seriously obstructed by the enormous pressures in the regions to be 
 explored, which deranged all common contrivances. The ordinary glass thermometers were repeatedly 
 tried in the Coast Survey soundings, hut as uniformly broken. Attempts were made to protect them by 
 strong metallic cases, which were also crushed in. Mr. Saxton, the eminently ingenious and successful head 
 of the Instrument Department in the Coast Survey Office, then devised the deep sea thermometer which 
 bears his name, and which has been used for several years with entire success. Some accidents, not 
 faults of the instrument, have had the effect to prevent such extensive observations as Mr. Bache had 
 provided for, hut it is to be hoped that each year will contribute to the number of our reliable observa- 
 tions with this elegant apparatus. \\e proceed to state its principle and the arrangement of its parts. 
 
 The main feature is a compound spiral of helical band or ribbon, 
 composed of two similar plates firmly united along their surface of 
 contact, the outer one being of silver, and the inner one of plati- 
 
 i 
 
 nurn. As the rates of expansion of these two metals are widely different, the variation of temperature 
 to which the spiral is exposed, will produce a considerable movement of torsion, or rotation at the bot- 
 tom of the helix, the top being fixed. This principle is familiar in Breguetfs torsion thermometer, and 
 Mr. Saxton has only applied it to a novel case, with an improved arrangement at the upper extremity of 
 the spiral, for magnifying and reading the indication furnished. The motion of rotation given by a 
 change of temperature, is very well fitted for reading, as by gearing it up, it gives a quite ample rota- 
 tion to an index hand. Within the spiral is a hollow tube, to which at the top the spiral is screwed fast, 
 as shown in fig. 1. Within this tube is a small rod or axle, which is connected with the bottom of the 
 spiral, and turns freely on a supporting pivot, so as to communicate the torsion rotation to a toothed 
 
THERMOMETER 
 
 719 
 
 silver wheel on its top, which is shown in fig. 2 ; that part only being toothed which will he needed. 
 A small pinion, which bears the index hand, takes up the motion, and is made to traverse the graduated 
 silver rim, and carry with it a stop hand, fig. 3, which will indicate the maximum or minimum tempe- 
 ratures passed in the descent, according to its arrangement. Suriace temperatures are read off at once, 
 and the sounding lines give the depths. _ 
 
 The whole of this arrangement is inclosed in a firm metal case, a§ shown in fig.. 4, which protects it 
 from injury, and yet permits the water to pass freely around the spiral, causing it instantly to take the 
 temperature of its locality. The top case is covered with a cap, pierced with small holes to permit the 
 water to pass freely. The whole case is then mounted in a metal frame by means of two rings. The 
 top ring turns on two side pivots, to permit the insertion of the case ; but the lower ring is in halves, 
 one of which is fixed, and the other opens out to receive the case, after which it closes, and is tightly 
 clamped. An eye at the top receives the sounding-line, and one at the bottom any requisite sinking 
 weights. All the delicate parts of this thermometer which could be corroded, are heavily electro-plated 
 with gold by Mr. Mathiot in the Coast Survey Electrotype Laboratory, so that they are not liable to 
 injury with fair treatment. 
 
 In using this instrument, it is thrown from the side of the vessel at successive times, first observing 
 the surface temperature, and then sinking it to a small depth, and again to one a little greater, and so 
 on, till it can be decided that the stop hand indication belongs to the greatest depth attained. The pass- 
 ing of a point of maximum or minimum temperature, however, complicates the problem, and makes it 
 a matter of critical judgment to connect the temperature and depth with accuracy. In the hands of 
 good observers, it yields excellent results, and, though not all that could be desired, is still a most excel- 
 lent instrument within the range of its capacities. Its cost, made in the limited numbers required in the 
 operation of the Coast Survey, is about sixty dollars, though a demand for considerable numbers would 
 much reduce this amount. We trust that this or some better instrument, if possible, will hereafter be em- 
 loyed with increased zeal in the study, not only of Gulf Stream temperatures, but of the ocean through- 
 out its whole expanse, and even in our lakes and the interior seas of the whole world. Surface tempe- 
 ratures alone are quite insufficient to give correct results, for the solar radiation produces a great effect 
 on the superficial layers, and we must penetrate to one or two hundred feet before we enter on the 
 grand temperature scale. A minimum temperature is usually passed in descending, at that depth where 
 the sun’s effects may be assumed to terminate, and we then enter on an increasing scale of tempera- 
 tures, which, according to one of Prof. Bache’s discussions, give, with the co-ordinates of depth, a curve 
 clearly and obviously the logarithmic curve. The connection between this result, and some of the 
 grand results of that theory of heat, which treats it as an elastic fluid, is striking and eminently sug- 
 gestive, though too recondite to be more than mentioned here. There is then a vast field of research, 
 full of interest and promise, for whose exploration this thermometer is, we believe, the most reliable in- 
 ttrument, and we trust it will therefore be put into increasingly active requisition. 
 
 THRESHING MACHINE, WATER, of eight horse-power. Fig. 3412 contains a side elevation of 
 the machine, and Fig. 3413 contains a plan of the same. 
 
 The same parts are denoted by the same letters in both of the drawings. 
 
 The water-wheel is of the kind denominated overshot , with wooden buckets. The shaft of this wheel 
 
720 
 
 THRESHING MACHINE. 
 
 rests on pillow-blocks bolted to the stone-work forming the sides of the wheel-pit. These pillow-blocks 
 have sometimes covers of the regular form, but more commonly they are unprovided with covers of any 
 sort; occasionally they are furnished with shell-covers for the sake of appearance, and to preserve the 
 gudgeons from water and sand. 
 
 On the end of the water-wheel shaft, which passes into the barn , is keyed a spur-wheel 1, of 121 
 teeth ; this wheel geers with the pinion 3, of sixteen teeth, upon the shaft B. On the other end of the 
 shaft is keyed the cog-wheel 2, of 115 teeth; this last geers with the pinion 4, of 15 teeth, on the end 
 of the shaft of a drum D, which carries on its circumference four projecting pieces called the beaters, 
 their purpose being to beat or thresh the grain from the straw as this passes forward between the feed- 
 rollers R, at the bottom of the feed-table F, upon which the unthreshen material is spread out in a layer 
 previous to its being introduced between the feed-rollers. The feed-rollers are both fluted, and derive 
 their motion from a pulley on the shaft B, by means of a pitch-chain 6, which passes over the pulley 8, 
 on the spindle of the lower roller. 
 
 On passing the beater-drum D, the straw is taken up by the two sets of shakers S S in succession. 
 The shakers are driven likewise from the shaft B by a pulley marked 7, and a pitch-chain which passes 
 over a pulley marked 5, on the shaft of the first set of shakers. The second set of shakers is connected 
 with the first by a pitch-chain, which passes over the equal pulleys a a, upon their shafts. 
 
 During the operation of threshing, the straw is tossed out behind the machine by the second set of 
 shakers upon a heck Y, and the grain falling through the sparred segmental bottoms H H, is collected 
 by the hopper kk into the fanner, situated below the machine, as shown in Fig. 3412. The- fan is 
 driven from the shaft of the beater-drum by a rope-band, which, passing from the pulley P on the 
 beater-shaft to the guide-pulleys b b, embraces the fan-pulley C, of the same diameter as P, so that the 
 
THROSTLE. 
 
 721 
 
 3413. 
 
 of the machine. 
 
 THROSTLE. A spinning frame for the manufacture 
 of cotton yarn of the lower numbers, say below 110’s 
 Throstles are designated as the live spindle , used in the 
 Middle and Southern States, the dead spindle used in 
 Lowell. The Cap Spinner, or Danforth Throstle; the 
 Ring Throstle, or Ring and Traveller. Figs. 341-1, 3415, 
 3410 represent one' of the latter class ; it differs from 
 the more common form of ring and traveller in its man- 
 ner of driving the spindle. In all other throstles the 
 motion is given to the flyer or to the spindle by a twisted 
 band, from a central drum passing round a small pulley 
 on the spindle. 
 
 fan and the beater-drum have the same speed, supposing no slip of the band. But the guide-pulleys b b 
 are usually fixed in a frame, which can be shifted vertically, so as to increase or lessen the tension of 
 the band at pleasure, according as the grain is heavy or light; for, when the grain is light, it will be 
 more easily blown away with the chaff than when heavy, and for that reason a certain amount of slip 
 of the band is allowed by lessening the tension, until the proper strength of blast is obtained. 
 
 The directions of the motions of the several parts of 
 the machine are indicated by arrows on the elevation 
 figures, and, indeed, are obvious from the mode of action 
 
 Fig. 3414 is an end elevation, showing the arrangement for the geers and belts for driving the rolls 
 and lifting motion for the rails. 
 
 Fig. 3415 is a front elevation, showing the rolls, spindles, and an edge view of the friction-disks a a 
 for driving the spindles. These disks and the whirls running upon them constitute the parts patented 
 by McCulley. The advantages derived by tins improvement are the saving of power, (which is 60 per 
 cent.,) and the dispensing with the bands, which constantly require tightening and renewing, also a great 
 saving in room, wear, and repair. The whirls, which are covered witli leather, will last several years 
 without need of repair. 
 
 Fig. 3416 is a vertical section of the machine through the centre of one section, showing the roller 
 stands s, the manner of weighting top-rolls by the weights g g, tile bearings for the side-shafts, stands 
 for the spindles, guide-rod d for raising top or ring rail, &c. 
 
 C is a collar on spindle in which the bobbin rests, b is the whirl on spindle resting on the friction- 
 disk a. E, weight to balance-rails, u is the heart, combined with geers and segment, which gives 
 motion to the ring-rail which forms the shape of the bobbin. 
 
 These frames are capable of being run at a great speed. The front roll may run at 130 revolutions 
 per minute for No. 14 yarn. 
 
 The live spindle, a great improvement upon the method first adopted by McCulley, is the application 
 Vol. II. — 46 
 
3410. 
 
 THROSTLE. 
 
TIMBER BENDING. 
 
 723 
 
 made by the Lowell Machine Shop, -who build frames of this kind to run with each side separate, thereby 
 stopping only half of the spindles while doffing. 
 
 In general arrangement, this machine differs but in the mode of driving from other ring-throstles ; 
 and in all respects but this the description applies to all ring-throstles. The older mode of driving is 
 by a central drum, from which bands, passing round whirls on the spindles, give motion to the same. 
 
 This latter mode of driving, by the friction of the whirl on the edge of a revolving disk, is fully tested 
 and very largely in operation. It gives a stronger, more regular and uniform motion to the spindle 
 than is given by bands, and is applied to driving the spindles, flyers, and bobbins of all kinds of thros 
 ties, also to worsted frames, and to doublers and twisters, with similar advantages. 
 
 TIMBER BENDING. The usual way of bending planks to curved forms, has been by straining or 
 heating the pieces and bending over a mould or frame, and leaving them* keyed in this position till they 
 had by cooling taken a set. This process not only strained the fibre of the wood, but was inapplicable 
 to the formation of curves of short radius in large scantling. In 1819 letters patent were granted to 
 Thomas Blanchard for improvements in bending wood and other fibrous substances. This patent claimed 
 the bending timber by placing a powerful pressure on the ends of the body ; and while the pressure was 
 continued, it was forced around a mould to the desired curve. The pressure upon the ends of the tim- 
 ber prevented the elongation of the fibre outside of the curve, while the inside was necessarily shortened, 
 thereby preventing the rupture or breaking of the same. 
 
 It was found, in the course of experiment in bending heavy timber for ships’ knees, requiring short 
 curves, that the timber, in the process of conforming to the mould, spread or bulged, much to its deface- 
 ment. To remedy this defect, Mr. Blanchard was employed to construct another machine, in all re- 
 spects adapted to bending ship timber. This was accomplished by encasing the timber on all sides, and 
 effectually preventing its spreading in any direction. This improvement was of vital importance in 
 bending heavy timber, and without which large knees could not be made. Previous to being subjected 
 to the pressure, the fibres of the wood are softened by steaming, which also incidentally by dissolving 
 the acid contained in the capillary vessels, increases the durability of the timber. 
 
 The fibres of wood have their origin in cells, generally shaped like a double cone, greatly elongated, 
 and placed close and parallel to one another, with the various extremities of one set wedged in between 
 those of another set. These fibres are generally collected together into layers, so arranged as to pre- 
 sent the greatest resistance to forces tending to displace them in the longitudinal direction. The masses 
 of fibre contain assemblages of cells which retain the air, fluids, gums, and resins of the tree. 
 
 In the application of heavy lateral forces to a body of wood, as in the operation of bending, the re- 
 sult is but a compression of its fibres to a solid mass, by the breaking up of the cells of which the fibres 
 are only the coat or covering. These fibres will remain under the action of any force, entire and con- 
 tinuous throughout the body, through their flexibility and elasticity, most hard woods being taken as a 
 standard. The grain of the wood or fibre is easily traceable, even at the point of greatest tension and 
 displacement, the angle at a short curve, where they interlace and lock each other so firmly as to hold 
 the extremities of a stick in position, after being bent to a right angle. 
 
 The aggregation and complication of the fibres at the angle of the curves, gives the greatest strength 
 where it is most required, as at that point one-fourth of every inch lost in bending the interior side of 
 the curve, is there gained. The severest tests have shown the impossibility of restoring a stick of tim- 
 ber, of whatever size, to its original form, after being subjected to this process ; fracture would first ensue, 
 but at those parts quite removed from the centre of the curve. Additional strength and elasticity are 
 given to a bent piece of wood, by the interstices and cellular spaces being filled up by the solid fibrous 
 material. 
 
 In 185G tests were made at the Brooklyn Navy Yard, under the direction of officers of the navy, with 
 the following results : 
 
 The knees upon which these tests were made, were of the largest size commonly used for hanging 
 knees. In order to make the test analogous to the appliance in the vessel, a piece of oak timber of equal 
 siding size with the knees, was fastened to the body, representing a timber of the ship’s frame ; also 
 another to the arm representing the beam of a vessel. The body was secured upon an iron frame, in 
 which the press rested, while the power was applied to the arm, on some, to contract the angle of the 
 knee, by drawing it inward to a point of rupture ; and on others, to thrust the arm outward to the rup- 
 turing point. In several cases, the fastenings were found inadequate to hold the beam and arm together, 
 although placed in about equal quantity, size and distribution, to the proportion commonly used in 
 vessels. It should be considered, however, that the knees were of more than ordinary stamp in quality. 
 
 Result of Tried. 
 
 No. 1 — Bent knee, sided 101 inches; moulded 10 inches at throat; remainder of size in throat made up 
 of chock on the comer; angle of knee, 95 degrees; power applied, 5.37 feet, from corner of arm; 
 and fulcrum at right angles with a point on the body, 1.92 feet from corner: 
 
 Bent inward, at \ inch required 5.500 pounds. I Bent inward, at 1-junch, required 8.500 pounds. 
 
 “ “ I “ “ 7.500 “ | “ “ 2 “ “ 10.000 “ 
 
 No. 2. — Natural, or grown, sided 10^ inches, moulded to corner; angle, 96 degrees; power, fulcrum, 
 and fastenings, same as No. 1 : 
 
 Bent inward, at it inch, required 3.500 pounds. I Bent inward, at 11 inch, required 7.000 pounds. 
 
 “ “ 1 “ “ 5.500 “ | “ “ 2 “ “ 9.500 “ 
 
 No. 3. — Bent knee, sided 10^ inches; moulded 11 inches in throat, and filled out to corner with chock, 
 angle, 88 degrees ; power applied as in No 1 and 2 ; fulcrum at middle of throat ; fastenings as before 
 distributed ; 
 
1 24 
 
 TOBACCO CUTTING MACHINE. 
 
 Bent inward, at 4 inch, required 6.500 pounds, j Bent inward, at 14 inch, required 10.000 pounds. 
 
 “ “I “ “ 9.500 “ | “ “ 2 “ “ 11.000 “ 
 
 Note. — T liis knee, (No. 3.) was "bent inward six inches, when the fastenings giving way, the knee was allowed to re- 
 turn, which it did; was re-fastened, and again bent inward, when it sustained within about 9 per cent, of its first 
 pressure. 
 
 No. 4. — Natural or grown knee, sided 104 inches; moulded to corner; angle square, or 90 degrees; 
 power applied, same as those before bent ; fulcrum at middle of throat, at angle of 45 degrees, with 
 arm and body : 
 
 Bent inward, at 4 inch, required 5.500 pounds. I Bent inward, at 14 inch, required 9.000 pounds. 
 
 “ “ 1 “ “ 7.500 “ | “ “ 2 “ “ 10.500 “ 
 
 No. 5. — Bent knee, sided 10 J- inches; moulded 11 inches; filled out to corner with chock; angle right, 
 or90 degrees; leverage as before, 5.37 feet from corner: fulcrum at right angles from middle of 
 throat, = to 3.08 feet : 
 
 Bent outward, at 4 inch, required 8.000 pounds. I Bent outward, at 14 inch, required... 18.000 pounds. 
 
 “ “ 1 “ “ ...14.000 “ I “ “ 2 “ *• ...22.500 “ 
 
 Note. — This knee, (No. 5,) was bent outward 10 inches, without the least rupture, and the highest resisting pressure 
 = 38.000* pounds; and on being relieved, returned to within 41 degrees of its former angle; was again subjected to 
 pressure, and when at 11J inches from its relieved position, the pressure amounted to 36.500t pounds. 
 
 No. 6. — Natural or grown knee, sided 104 inches ; moulded to corner ; full and well-grown, with 5 feet 
 arm, the very best the Navy or market could furnish : was prepared at the navy yard, angle 82 de- 
 grees ; fastenings, leverage, and fulcrum as before applied ; one inch larger in body at commencement 
 of throat. This knee had two trials, in consequence of the necessity of re-arranging to secure equal- 
 ity of position. 
 
 On First Trial. 
 
 Bent outward, at 4 inch, required 7.500 pounds. I Bent outward, at 14 inch, required. ..26.500 pounds, 
 
 “ “ 1 “ “ ...20.000 “ | “ “2 “ “ ...33.000 “ 
 
 On Second Trial. 
 
 Bent outward, at 4 inch, required... 11.500 pounds. I Bent outward, at 14 inch, required. ..31. 500 pounds. 
 “ “ 1 “ “ ...22.500 “ | “ “ 2' “ “ ...38.500 “ 
 
 It broke at two inches in the throat, the rupture being complete. Blanchard’s patent has passed into 
 the hands of the Timber Bending Co., who have now nearly ready for operation an improved machine, 
 with capacity to bend timber fifty feet long and twenty inches square. 
 
 TOBACCO-CUTTING MACHINE. This is a superior constructed tobacco-cutting machine, the in’ 
 vention of A. P. Finch, Red Falls, Greene Co., N. Y. Its workmanship is of a very superior kind, 
 strong, correct, and simple, and there can be no question of its qualities. 
 
 A, Fig. 3419, is the frame; BB are two wheels on which is fixed the cutting-knife C, across the end 
 of the box D ; E is the lid of the box, under which is pressed down the tobacco to be cut, by four screws 
 FFFF. As the tobacco to be cut has to be pressed down to a very solid bed, two cross-bars extend 
 under the nuts of the screw-bolts across the box D, on the top of the cover E, and there are notches in 
 
 3419. 
 
 N 
 
 the sides of the box to allow these bars to descend with the cover on the top of the tobacco as it is 
 screwed down. H is a cog-wheel on the screw L. The screw passes through it, and as there is a 
 thread in the interior of the wheel, the screw will be moved forward or backward by the motion of the 
 wheel. On the end of the screw in the box there is a square block pressing behind the tobacco to movf 
 
TOOLS. 
 
 725 
 
 it gradually towards the knife. This is the office of the screw. Therefore as the knife cuts up the to- 
 bacco under E, at the right end of the box, the screw pushes up the compressed tobacco to present al- 
 ternately a new layer of tobacco to the knife at every revolution of the revolving cutter-wheels B B. 
 N is a fly-wheel on the cutter-shaft, and the pulley on the left of the cutter is for a band to drive the 
 shaft. The cog-wheel F, at the left end of the box, is driven by a worm-wheel J, (scarcely seen,) under 
 the bottom of the box. K is a set of pulleys on the shaft of J to drive the said shaft, so that the screw 
 may receive a forward or backward motion by the changing of the band. The handle on the end of the 
 screw is merely to show the manner in which it may be turned. 
 
 TOOLS. The great and manifest importance of tools to the mechanic is so self-evident that it is ex- 
 traordinary the subject has not hitherto received that investigation which it obviously deserves. The 
 vast improvements in modern machinery are mainly attributable to the excellence and accuracy of the 
 tools used in preparing and completing the various parts of which every machine is composed. 
 
 By the expression tools, according to the definition given by Mr. George Rennie, we understand in- 
 struments employed in the manual arts for facilitating mechanical operations by means of percussion, 
 penetration, separation, and abrasion of the substances operated upon, and for all which operations 
 various motions are required to be imparted either to the tool or the work. 
 
 For the sake of distinctness it would be desirable, so far as is practicable, to treat the subject under 
 two points of view: 1st. Where motion is given to the tool, as in handicraft work; 2d. Where motion 
 is given either to the tool or the work, as in self-acting or automatic tools. Now, in the case of the 
 turning-lathe the tool usually remains fixed, while the object invariably moves — in that of the planing- 
 machine the tool or cutter may either remain fixed or be made to move, according to the duty required 
 to be performed. In almost all the other machines which come under the denomination tools — such, 
 for example, as are intended to perform the various mechanical operations of slotting, key-grooving, 
 punching, drilling, nut-trimming, cutting the teeth of wheels, boring, screw-cutting — the tool receives 
 motion, although in some cases, particularly in the nut-trimming and screw-cutting machines, the tool 
 may be either movable or fixed. 
 
 It would afford much matter for curious and instructive inquiry to trace the early history of tools, as 
 there can be little doubt that the use of handicraft tools is coeval with the earliest ages ; and assuming 
 the recent researches of modern travellers to be satisfactory proof of the fact that the ancients were 
 acquainted with almost all the tools now in use, we cannot fail to admire the patient perseverance of 
 the workman, whose skill, combined with manual labor, enabled him to produce so many beautiful spe- 
 cimens of his art— a circumstance the more remarkable when we consider the rude and simple imple- 
 ments by the aid of which this extraordinary degree of excellence was attained. 
 
 The gradual improvement in tools, which of late years have reached a very high point of perfection, 
 is well illustrated by the wheel-cutting and dividing-engine. We therefore propose very briefly to 
 sketch the history of those machines and appliances which come under the general name above prefixed. 
 
 While the art of constructing wheel-work was in a less advanced state, the dividing of the circum- 
 ference of a wheel into the requisite number of parts, and cutting out the tooth spaces by a manual 
 operation, was not only a tedious but also an extremely imperfect way of proceeding. To facilitate 
 such manual operation by a file, the simple platform described by Pere Alexandre, in his Treatise on 
 Clock-making, was invented ; this platform was simply a circular plate of brass, of ten or more inches 
 in diameter, with concentric circles traced thereon corresponding to the numbers of teeth in the wheels 
 and pinions of clock-work. In the centre of this platform was fixed a stud or fast arbor, round' which 
 an index, with a straight edge pointing to the centre, turned freely into any given point of a required . 
 circle, by means of which the divisions of any given circle were transferred to a wheel placed on the 
 central arbor under the index already described, by a marking point. This mode of dividing a wheel 
 is still practised in some branches of the mechanical arts, and is, doubtless, an easy way of transferring 
 divisions from a larger to a smaller circle for various purposes, where rigid accuracy is not required. 
 But one great difficulty still remained to be surmounted : the spaces necessarily required to be cut by 
 hand with a file. At length a small frame was mounted on the index, which was contrived to direct 
 and confine the file in such a way as to cut the notches in a wheel placed over the index, with less de- 
 viation from the truth than could be managed by mere manual dexterity. It is extremely probable 
 that this addition led to the adoption of a circular file or cutter, and of such other appendages as com- 
 pleted the construction of a simple wheel-cutting machine, and it is asserted by M. Le Roy that Dr. 
 Hooke was the first person who contrived such an arrangement as could 
 merit the name of a cutting-engine. The machine thus converted into a 
 self-acting piece of mechanism was made up of the strong frame, the slid- 
 ing-bars for supporting the platform or plate, with a horizontal screw for 
 adjusting the distance from the circular file, the divided plate with a re- 
 volving arbor to receive the wheel to be cut, and the alidade or index fixed 
 to the great frame in the position of a tangent line to any of the divided 
 circles, and applying its bent and rounded point to any of the pierced 
 marks of division on the circle successively, as the plate revolved, during 
 the operation of cutting the successive teeth of a wheel. This construc- 
 tion of the engine is very nearly identical in principle to that used in the 
 present day, more especially for cutting the teeth of small wheels, as shown 
 in Fig. 3420. Here A shows the arbor on which the wheel to be cut is 
 fixed. B, the cutter. 0, a toothed-wheel worked by the handle E, and 
 faking into the pinion D, which being on the same axis as the cutter B, 
 imparts to it a velocity proportionate to the number of teeth in the wheel 
 C, and the pinion D. F is a lever-handle by means of which the swinging frame may be gradually 
 depressed as the cutter B is brought into operation, or raised when it lias performed its work. G 
 the horizontal screw of adjustment ; H, the division-plate, and I the index or pointer. 
 
 3420. 
 
 c,<r? 
 
72G 
 
 TOOLS. 
 
 The original divisions of the circle, namely, 360, 300, 150, 90, 60, <fcc., are commonly retained in tho 
 ordinary engines, although many of the smaller numbers are included in the larger ones, and are, there- 
 fore, superfluous; lor, taking every fourth hole in the circle of 360, gives precisely the same result as 
 using the circle of 90, or every sixth as using the circle of 60, and, in like manner, taking every other 
 hole in the circle of 300, will be precisely the same in effect as using the circle of 150. It must, we 
 think, be obvious to every one, acquainted with the ordinary process of cutting the teeth of wheels, 
 that engines, of the construction just described, are very limited in their operations, by reason of their 
 powers extending only to the numbers marked on the divided circles, or the factors of which those 
 numbers are composed, and because the prime numbers are not usually inserted. To remedy this de- 
 fect, and at the same time render the engine of greater practical utility, appears to have been a favorite 
 study with different ingenious artisans, whose daily avocations admirably qualified them to appreciate 
 the improvements we have already referred to, as well as to devise such additional apparatus as would 
 make the engine more perfect. 
 
 It is unnecessary to pursue further the minute details of this subject, but it is to be observed that the 
 only true and accurate method of circular division, namely, by a tangent-wheel and endless screw, first 
 contrived and used by Dr. Hooke in 1 661, for the purpose of dividing astronomical instruments, has 
 been from time to time advantageously applied to the wheel-cutting engine by eminent mechanicians. 
 
 We now proceed to the dividing-engine, of which it has been justly observed, that “ none has so much 
 contributed to the interest of navigation considered as a science indeed the facility, and at the same 
 time the accuracy, with which the measuring portion of any astronomical or mathematical instrument, 
 however portable, can now be divided by our best engines, are truly astonishing ; the fine lines of divi- 
 sion which in many instances are scarcely visible to the naked eye, are, when magnified by a suitable 
 lens, perceived to be laid down with perfect equality, as to relative distance, so much so, that no one 
 who has not examined the means by which the result is produced, can conceive the possibility that the 
 expedition with which the divisions are made, is equal to the accuracy with which they are measured 
 and marked down. 
 
 Several trials were made at the Greenwich Observatory, by Flamsteed, the Astronomer Royal, but 
 the method was found defective, probably in consequence of imperfect workmanship, and was soon 
 abandoned. In Mr. Smeaton’s paper, read before the Royal Society of London, November 17th, 1785, 
 on the “ Graduation of Astronomical Instruments,” he mentions an engine made by Mr. Henry Hindley 
 of York, which indented the edge of any circle in such a way that a screw with fifteen threads acting 
 at once, would, by means of a micrometer, read off any given number of divisions, so as to answer the 
 purpose of subdividing the circle. Mr. Ramsden, in consequence of the reward offered by the Board of 
 Longitude to Mr. Bird, for his method of dividing, in the year 1760, turned his attention towards the 
 contrivance of an engine that would divide nautical instruments with sufficient accuracy, without resort- 
 ng to the delicate and tedious process of manipulation, practised by Mr. Bird. Lie completed an en- 
 gine with an indented plate, or wheel of thirty inches diameter, which, though it did not entirely answer 
 hi3 expectations to their full extent, yet was found very useful for dividing theodolites, and such like 
 instruments, with great facility. This was effected before the spring of 1768; and in 1771, a much 
 larger and more efficient engine was produced, with an indented plate of forty-five inches diameter, 
 which divided a sextant for Mr. Bird’s examination so accurately, that the Board of Longitude, ever 
 ready to remunerate any successful endeavor to promote the lunar method of determining the longi- 
 tude at sea, did not hesitate to confer a handsome reward on the inventor, but on the express condition 
 that the said engine should be at the service of the public, and that Mr. Ramsden should publish an 
 explanation of his method of making and using it. 
 
 In 1820, Mr. James Allan was rewarded by the Board*of Longitude with one hundred pounds, 
 f r his improvement on Ramsden's dividing-engine. This improvement consists in the method em- 
 ployed to cut or rack the teeth around the periphery of the great circle, worked by an endless screw, 
 upon which the arc to be divided is placed, so as to insure perfect equality of size, as regards the teeth, 
 in all parts of the circle. This extremely ingenious, though simple contrivance of Mr. Allan, is described 
 in the transactions of the Society of Arts. The great circle of bell-metal, a semi-plan of which is shown 
 in Fig. 3121, is mounted upon an axis A, and its surface made truly plane and perpendicular to the 
 axis ; the section shows the figure of the axis, and the central ring B, to give the greatest strength to 
 the circle ; C is a section of a portion of the frame of the engine ; and D, a socket into which the axis 
 A is fitted; the circumference of the large circle is then turned to such a figure as to receive a ring oi 
 brass a, which is united firmly to it by a number of pins. Upon this ring a second, b, is placed, the two 
 
TOOLS. 
 
 727 
 
 making the same thickness as the circle, a sectional view of which is here introduced. The inside of 
 the ring b, and the outside of the bell-metal circle, are fitted to each other with the greatest accuracy 
 and great care taken to turn the same truly fitting concentric with the axis of the circle ; the brass 
 rings a and b are held together by twenty- four screws, and a groove corresponding to the curvature ot 
 the screw which moves the circle is then turned in the outside of the two ; in this state the racking of 
 the teeth is performed by a screw similar to that afterwards used to turn the circle to its divisions, but 
 notched across the threads so that it cuts like a saw, when pressed against the circle and turned round, 
 and removes the metal from the spaces between the teeth, which are by this means formed around the 
 edge of the circle ; when this has been performed all round, two fine lines are drawn across the brass 
 and bell-metal circles, diametrically opposite to each other ; the twenty-four brass screws are then 
 withdrawn, and the upper brass ring turned exactly half round, which is determined by the lines before 
 mentioned ; and by this means the teeth of the circle are divided into two thicknesses, and being put 
 together again in opposite directions, if any error arose in racking the teeth, it would be shown by the 
 upper and lower halves of the teeth not coinciding when reversed, and by racking them while reversed, 
 the screw would cut away the inequalities, and make all the teeth of the same size and distance from 
 each other; this reversing the teeth is performed several times, till the teeth are brought to a perfect 
 equality in all parts of the circle ; four steady pins are accurately fitted into the two rings to hold 
 them together in any of the positions in which they have been racked together, and it is upon them 
 that dependence is placed for the coincidence of the teeth, the twenty-four screws being merely 
 to hold them fast together, and fitted rather loosely in their holes that they may not strain the 
 steady-pins. 
 
 We have purposely omitted any mention of the improved engine by Mr. E. Troughton, in who3e 
 hands the art doubtless arrived at a high degree of exactness, because, to adopt the language of a com- 
 petent judge, there are various difficulties in the application and construction of the apparatus, to avoid 
 which was the avowed object of the engine now in part to be described, by adopting principles perfectly 
 independent of mechanical action, and governed only by vision, assisted by the most powerful optical 
 means. For this really scientific piece of mechanism we are indebted to Mr. Alexander Ross, mathe- 
 matical instrument maker, to whose ingenuity the Society of Arts of London, in 1831, awarded the Gold 
 Isis Medal and fifty guineas. 
 
 Fig. 3422 is a side view of Mr. Ross’s apparatus for cutting original divisions, and consists of the fol 
 lowing parts: a small circle 10 or 12 inches diameter, divided into spaces of 3° 45' or 96 parts, by the 
 usual dividing-engine or by any ordinary means — -two micrometer microscopes, represented at a b an 
 arc co of the length of 3° 45' of the circle to be divided — a cutting-frame <1 e, and a frame ffgg to sup- 
 port the apparatus. The frame fg consists of a bottom and top plate connected by two strong pillars, 
 one of which is represented at li, the front one being removed to show the other parts. In the bottom 
 plate are screwed the nuts i i which form adjustable feet for the frame ; these nuts are perforated, an-j 
 the screws jj pass through and fasten the whole securely, after being levelled by the nuts i and the 
 level l. The upper plate is secured to the pillars h by two screws and collets, moving on the one as a 
 centre, and adjustable at the other by the pushing screw n for the purpose of setting the cutting-point 
 o, which is attached to the upper plate / - , to cut a radiating division on the circle to be divided: an arc 
 and index not capable of being shown in a side view, indicate the inclination given. To the upper plate 
 is likewise attached the hollow centre q ; in this works a male centre, the flanch of which is seen at r ; 
 this supports the bar ss which carries the microscopes a b and the level l. The microscopes are secured 
 to this bar by two pulling and two pushing screws tt,tt, passing through a flanch v, and acting ih and 
 on the bar s. The microscopes are secured to the flanch by fitting into strong tubes u u, and when ad- 
 justed to distinct vision can be fixed in that position by the clamping-rings w w. The handle x x for the 
 cutting-frame is attached to the perpendicular sling d, having a double joint at the point where it is 
 fixed, in order to prevent any unequal pressure from producing a lateral motion of the cutting-point ; 
 the other end is connected to the upright dovetail slide 34, which forms part of the apparatus for mov- 
 ing the cutting-point. (See article Automatic, in 1st volume of this Dictionary.) 
 
 From a consideration of the foregoing sketch we draw the following conclusion, namely, that the dif- 
 ficulties and failures which have from time to time checked the progress of inventive genius are to be 
 traced to two sources: first, a limited knowledge of elementary principles; and secondly, the defective 
 construction and consequent imperfect performance of the tools employed. 
 
 One of the most valuable aids to the more perfect construction of machinery is due to Mr. Joseph 
 Whitworth, of Manchester, who has recently introduced the simple process of scraping, instead of the 
 dirty and unsatisfactory operation of grinding, as a means of producing plane metallic surfaces. It is 
 essentially required in a surface for mechanical purposes, that all the bearing points should be in the 
 same plane, that they should be equidistant from each other, and that they should be sufficiently nu- 
 merous for the particular application intended. Where surfaces remain together in fixed contact, the 
 bearing points may, without disadvantage, be fewer in number, and consequently wider apart ; but in 
 the case of sliding surfaces the points should be numerous, and in close approximation. 
 
 A little consideration will make it evident that these conditions cannot be obtained by the process of 
 grinding. And first, with regard to general outline, how is the original error to be got rid of ? For if 
 it be supposed that one of the surfaces is concave, and the other a true plane, then the tendency of 
 grinding, no doubt, would be to reduce the error of the former, but the opposite error would at the same 
 time be created in the true surface. The only case in which an original error could be extirpated, 
 would be when it was met by a corresponding and contrary error of exactly the same amount in the 
 oj posed surface; but it is evident that where only two surfaces are concerned, the variety of error in 
 the general outline is not sufficient to afford any probability of mutual compensation. It will furthei 
 appear, that if the original error be inconsiderable, the surfaces must lose instead of gaining truth. It 
 results from the nature of the process that certain parts are acted upon for a longer time than others ; 
 the} r are consequently more worn, and the surfaces are made hollow; nor is there any probability o' 
 
728 
 
 TOOLS. 
 
 obviating this source of error except by sliding the one surface entirely out of the other at each move, 
 a method which is clearly impracticable. 
 
 It may be mentioned as an additional cause of error, that the grinding powder collects in greater 
 quantity about the edges of the metal than upon the interior parts, producing the well-known effect ol 
 the bell-mouthed form. This is particularly objectionable in the case of slides, from the access afforded 
 to particles of dust, and the immediate injury necessarily occasioned thereby. Another circumstance 
 materially affecting the durability of ground slides is, that a portion of the emery becomes fixed in the 
 pores of the metal, and can never be entirely eradicated therefrom, causing a rapid and irregular wear 
 of the surface. 
 
 If, then, grinding be not adapted to form a true general outline, neither is it to produce accuracy in 
 the minuter detail. There can be little chance of a multitude of points being brought to bear, and dis- 
 tributed equally under a process from which all particular management is obviously excluded. To 
 obtain any such result, it is necessary to possess the means of operating independently on each point as 
 occasion may require, whereas grinding affects all simultaneously. It is subject neither to observation 
 nor control, there is no opportunity of regulating the distribution of the powder, or of modifying its ap- 
 plication, with reference to the particular condition of the different parts of the surface. The variation 
 in the quantity of the powder and the quality of the metal will of necessity produce inequalities, even 
 supposing they did not previously exist. Hence, if a ground surface be carefully examined, the bearing 
 points will be found lying together in irregular masses, with extensive cavities intervening. An ap- 
 pearance indeed of beautiful regularity is produced, to which, no doubt, we may trace the universal 
 prejudice so long established in favor of the process; but this appearance, so far from being any evi- 
 dence of truth, serves only to conceal error, and under this specious disguise surfaces pass without 
 examination, which if unground would be at once rejected. 
 
 In addition to what has been stated, it must be remembered another great evil of grinding is that it 
 takes from the mechanic all sense of responsibility and all spirit of emulation, while it deludes him with 
 the idea that the surface will be ultimately ground true ; hence he slurs his work over in a slovenly 
 manner, trusting to the effect of grinding, being conscious that it will efface all evidence either of care 
 or neglect on his part. 
 
 Thus it appears that the practice of grinding has altogether impeded the progress of improvement. 
 A true surface, instead of being, as it ought, in common use, was until lately almost unknown ; few 
 mechanics have any distinct knowledge of the method to be pursued for obtaining it, nor do practical 
 men sufficiently advert either to the immense importance or to the comparative facility of the acquisi- 
 tion. The expression “true surface” may appear contradictory, and therefore require qualification. 
 Absolute truth is confessedly unattainable ; moreover, it would be possible to aim at a degree of perfec- 
 tion far beyond the necessity of the particular case, the difficulty of which would more than counter- 
 balance the advantage ; nevertheless it is certain that the progress hitherto made falls far short of this 
 practical limit, and that considerations of economy alone would carry improvement many degrees 
 higher. The extensive class of machinery denominated tools, affords an important application of the 
 subject; here every consideratiou combines to enforce accuracy. It is implied in the very name of the 
 planing engine, the express purpose of which is to produce true surfaces, and it is itself constructed of 
 slides, according to the truth of which will be that of the work performed ; and when it is considered 
 that the lathe and the planing engine are employed in the making of all other machines, and are con- 
 tinually reproducing surfaces similar to their own, it will manifestly appear of paramount importance 
 that they should themselves be perfect models. Indeed it would be difficult to mention any description 
 of machinery which would not serve as an illustration of the importance belonging to truth of surface, 
 and at the same time offer abundant evidence of the present necessity for material improvement ; nor 
 is there any subject connected with mechanics, the bearings of which, whether regarded in a manufac 
 turing or scientific point of view, are more varied or more extensive. 
 
 The tool employed for scraping is not only simple but easily made ; it should be of the best cast-steel, 
 and carefully sharpened to a fine edge on a Turkey-stone, the use of which must be frequently repeated ; 
 but worn-out files may be converted into convenient scraping-tools. A flat file with the broad end bent 
 and sharpened will be most suitable in the first instance, and afterwards a three-angled file sharpened 
 on all the edges. The process of scraping is equally simple, requiring rather care than skill on the part 
 of the work man, whilst it affords a certain and speedy means of attaining any degree of truth that may 
 be deemed necessary, thus tending to the gradual establishment of a higher standard of excellence, the 
 influence of which cannot fail to affect beneficially all mechanical operations, opening at the same time 
 to the mechanic himself a new field in which he will find ample scope for the exercise of skill, both 
 manual and mental. 
 
 We are now in a condition to proceed with the matter more immediately under consideration. The 
 value of every cutting instrument depends upon the excellence of the steel of which it is made, the care 
 bestowed daring the several processes of forging, hardening, and tempering, and the just adaptation of 
 the angle or bevel which forms its edge to the work it is intended to perform. Generally speaking, this 
 angle is determined by the hardness of the substance to be operated upon. Thus we see chisels for 
 cutting soft woods are thinner than those used for the harder species, and these again are more acute 
 than chisels employed for cutting metals, or in other words, the greater the resistance offered by the 
 material to be cut, the more obtuse must be the angle of the tool. This definition is not propounded as 
 rigidly correct in all cases, although it is susceptible of abundant practical illustration ; for example, in 
 hand-turning, the workman is enabled by raising or lowering the T of the rest, to vary the direction and 
 limit the cut of the tool employed, according to circumstances. This one fact, amongst a multitude oi 
 others equally palpable that could be adduced, might have been expected to induce inquiry and inves- 
 tigation. On the contrary, we have the authority of Mr. Nasmyth for stating that the form of tools, 
 more, especially those us.ed in turning and planing iron, brass, <fec., has not hitherto received either that 
 attention which the importance of the subject calls for, nor has any attempt been made to reduce it to 
 
TOOLS. 
 
 729 
 
 plain and general principles, of which it is highly susceptible, and if so treated would be of much service 
 to those in whose hands the management of such tools is for the most part intrusted. So many consid- 
 erations of a practical nature are inseparable from this subject, that the quality as well as the quantity 
 of work produceable from turning lathes and planing machines depends entirely upon the skill of the 
 workman in giving to his tools the proper form. 
 
 The general principle propounded by Mr. Nasmyth, which is equally applicable whether the motion 
 be horizontal, circular, or vertical, is deduced from a consideration of the direction in which the metal 
 is to be cut or penetrated. With regard to the first case, as in the planing machine, it is manifest that 
 the face of the tool is at right angles to the plane of the material to be cut, and consequently, if its point 
 or cutting edge be made in the form of a very obtuse angle, it will possess little or no penetrating qual- 
 ity — such a tool would not cut, but rather abrade, or probably crush off the particles of metal. Again, 
 if wo resort to the other extreme, and give to the cutting edge the shape of an extremely acute angle, 
 we shall find, however sharp it may appear, a total absence of penetrating quality, or at all events in 
 the required direction, and what is equally objectionable, the point being weak would snap off, incajja- 
 ble of resisting the least applied force. 
 
 From an investigation of these and other obvious facts, Mr. Nasmyth concludes that a tool of the 
 form shown in Fig. 3423 fulfils the requisite conditions, as it combines a high degree of acuteness with 
 sufficient strength — the former in the direction of the cut, and the latter behind the point or cutting edge, 
 where it is most needed. Hence the following principle may be established, namely, that in forming 
 and setting a tool to cut any surface, it is (jssentially necessary so to place it that the end shall form the 
 least possible angle with the surface to be cut, or in other words, as nearly parallel as possible, and what- 
 ever degree of acuteness may be deemed necessary must be obtained by hollowing out the face E C, on 
 which the shavings slide. An apt and very familiar illustration of the principle may be drawn from the 
 common plane of the joiner. An artificial end being given to the plane-iron, which is here the cutting 
 tool, by means of the sole of the plane, this necessarily limits the penetrating quality in all directions 
 except that in which it is required to remove the material. Further, it can scarcely have escaped ob- 
 servation that the bevelled surface of a chisel is invariably placed outwards, and the flat surface next 
 to the wood, so that the face of the chisel next the wood and the surface of the wood itself shall form 
 the least possible angle. 
 
 The same principle is similarly true in the case of turning-tools, and indeed in every tool, from the 
 smallest and most delicate of the clock and watch maker, up to the largest and most powerful tool in 
 an engineer’s lathe or planing machine. 
 
 As regards circular motion, we have a clear exemplification of the principle by merely considering 
 the tool already described as a turning-tool. In Fig. 3424, A B shows a section of a cylindrical bar in 
 the lathe, and E F so placed as to be, as nearly as circumstances will permit, a tangent, that is, at right 
 angles to the radius of the curve — the requisite acuteness being obtained, as before, bv hollowing out 
 the face E C. 
 
 The same principle applies to drills. Thus Fig. 3425 being the end view of a drill, the edge 0 P 
 should be in the least degree prominent or out of the plane of the surface, of which the bounding lines 
 are the edges, 0 S being slightly less prominent than O P, so that the penetrating quality at the edge 
 0 P may be limited as much as possible. An adherence to these rules will produce a drill that shall 
 cut a smooth and equal hole, without chattering, as is commonly the case when the edges are bevelled 
 very much back, as shown at R. The necessary acuteness to the cutting edge of the drill is easily ob- 
 tained by merely observing the principle laid down in respect to turning-tools, that is, by hollowing out 
 a groove at X, on each cutting face. 
 
 Every mechanic is sensible of the value of good tools as necessary appliances to the performance of 
 his work more quickly, with less exertion, and more accurately than can be done with inferior ones ; yet 
 how few are in a position to answer this apparently simple question, what constitutes this quality de- 
 nominated goodness ? The excellence of cutting-tools is generally decided by their relative degrees of 
 endurance, but how many incidental circumstances may, and frequently do, interfere to vitiate any ac- 
 curate comparison. As regards hardness, nearly the only test is the resistance the objects offer to the 
 file, a mode extremely fallacious, because files differ among themselves in hardness, and at best only 
 serve to indicate in a very imperfect manner, to the touch of the individual, a vague notion without any 
 distinct measure. Take, for example, two chisels for turning iron, both of cast-steel, and from the hands 
 of the same maker, and although precisely alike in outward appearance, the one may be absolutely 
 worthless and the other equally valuable. Nay, one portion of the same chisel may be good and the 
 other bad. If during the process of fabrication of two cutting-tools the same treatment be practised 
 witli similar care, we should naturally expect, all things being coincident, that the one would correspond 
 with the other. Experience shows the fallacy of this mode of reasoning. Nearly every metal-turner 
 makes his own tools, and for this plain reason, that he cannot place any dependence on those he pur 
 chases. The smith who forges, hardens, and tempers these tools, rarely uses them ; he labors to pro- 
 
730 
 
 TOOLS. 
 
 duce a certain number in a given time, and if they satisfy the eye his o eject is attained. The good or 
 bad quality of a tool depends more on the care and attention bestowed during the process of forging 
 than is commonly imagined, and the defects, whether of texture or edge, which so often present, them- 
 selves in articles manufactured of steel, are to be traced not so much to any natural imperfection or 
 partial conversion of the metal, as to a slovenly and hasty mode of forging. (See Steel.) 
 
 The tool employed for chipping is simply a chisel with an edge assuming the shape of an acute 
 wedge ; it is ordinarily made from square or oval steel of the best quality, rather spread out at that 
 end which is intended to form the edge, so as to afford a greater surface. Whatever may be the 
 length of the chisel, whether six or eight inches — and this must depend in some measure upon the na- 
 ture of the work — the form of the cutting edge is in all cases nearly similar ; observing, however, that 
 it is advisable to have the chisel drawn out by the smith, by which precaution the edge, when injured, 
 may be more easily restored on the grindstone. The operation of chipping is materially facilitated by 
 the use of the cross-cutting chisel, of which Fig. 3420 shows a front and Fig. 342*7 a side view, a a' in 
 the latter figure being a section. The cutting edge of this extremely useful tool varies in breadth from 
 one-sixteenth to five-sixteenths of an inch ; its utility and application will probably be rendered more ob- 
 vious to the reader by a diagram than by any lengthened verbal explanation. 
 
 Suppose the surface of a block of cast-iron, represented by Fig. 3428, to require chipping. In the 
 first place, the workman cuts longitudinal grooves a a', h b', cc\ throughout or across the entire length 
 or breadth of the surface by means of the cross-cutting chisel, and at such a distance from each other as 
 is rather less than the width of the chipping chisel intended to be subsequently employed ; by which 
 means the corners of the edge of the chipping chisel are essentially preserved from injury, as under or- 
 dinary circumstances it is found that the corners of the chisel first give way, and require constant repair. 
 
 The interior portions of any piece of metal are usually removed by a tool called a drill. Boring dif- 
 fers from drilling principally, as we shall hereafter show, in being applied to larger works. The class 
 of tools which come within the general description of drills, or cutters, is extremely numerous ; that 
 more commonly employed is too well known to require description, more especially as we have already 
 given Mr. Nasmyth’s imjrroved form of this tool. The pin-drill and half-round drill are, in certain cases, 
 extremely useful ; the only objection to the former is, that it requires a small hole to be first cut in and 
 through the metal in which the pin of the drill works and necessarily follows ; it answers, however, for 
 
 3420. 3427. 3431. 3430. 3420. 
 
 ill ordinary purposes, and performs its work extremely well, although it cannot be depended on in 
 cases where rigid accuracy is required. The half-round drill offers little or no security whatever as re- 
 gards piercing in a right line ; it is, however, a very useful tool, and may, in many instances, be advan- 
 tageously employed. Perhaps the most effective form of drill yet introduced, more especially if ap- 
 plied to any metallic substance revolving in a lathe, is that invented by M. Collas, an eminent French 
 mechanician. This tool, of which Fig. 3429 is a front view, and Figs. 3430 and 3431 side views, taken 
 from from e and/, is turned truly cylindrical throughout its entire length, except at that end which is 
 intended to fit into the brace, or if used in a lathe a small portion of the metal is filed square, or the 
 edges taken off to admit of any convenient mode of preventing the drill turning. At the other or oppo- 
 site extremity of this cylinder of steel, and through the centre a small hole is drilled in proportion to the 
 size of the tool ; one half of a portion of the bar is then cut away, leaving the remainder cylindrical; 
 this part is then equally divided into three, and one of them filed out, as is clearly shown in the plan 
 views of Figs. 3429, 3430, and 3431, by which process the central hole is cut into two equal parts, and 
 becomes a small semicircular groove. With regard to the angle of inclination to be given to the cutting 
 end of the drill, this must depend principally upon the resistance offered by the material.* This tool 
 manifestly cuts circularly, except at the centre, where it forms a small projecting pin, which enters the 
 central groove and serves as a conductor; in proportion as the tool advances this pin increases in length 
 until it reaches the extremity of the groove, when it necessarily breaks and comes away with the chips. 
 It is important to observe that this groove must be rather less than greater than a semicircle, otherwise 
 the pin of metal which enters therein, being cylindrical, could not leave it during the progress of the 
 operation, and the distinguishing feature of this tool would be destroyed. 
 
 Small drills are commonly made of a single piece of steel wire, upon which, near to the middle, a 
 pulley or drill-barrel is driven. Occasionally a small mandrel is used, provided at one end with a square 
 
 * Drills or boring-bits ought to have the angles of their edges varied according to the nature of the metal to be bored ; 
 thus, wrouglit-irou would require a very different angle from that used for cast-iron. If in use, the bit trembles or jars, it 
 is a sign that the angle is too acute, and must be made more obtuse, or nearer to a right angle with the plane or Hat lacy 
 of the drill. Again, if the obliquity of the other, or crossing angle, be too great, the tool will also have too great a ten- 
 dency to form a nipple or cone in the centre of the bottom of the hole, and to bore the hole gradually wider aDu wider 
 instead of truly cylindrical, as it will do when properly formed; and that fault must therelore be corrected by grinding the 
 drill or bit so as to reduce its obliquity, or bring it nearer to a right angle with the sides of the bit 
 
TOOLS. 
 
 781 
 
 hole about half an inch deep, into ■which drills of various dimensions can be inserted. The disadvan- 
 tage of this mode of construction is, that the drill is rarely placed true in the mandrel, which necessarily 
 causes it to perform indifferently; it is, therefore, but seldom employed by practical men who have the 
 convenience of readily sujoplying themselves with drills of various dimensions as required. 
 
 When small drills are used they are held horizontally and kept up to the work by a breast-piece, 
 which is usually made of wood, armed with a plate of steel superficially pierced with holes of different 
 dimensions, in one of which the blunt end of the drill works. The drill receives a reciprocating motion 
 from an elastic bow, the spring of which is coiled once round the pulley. Common bows are ordinarily 
 made of stout cane, those of a better description of steel, and the string of catgut, but the strength of 
 both must necessarily be proportioned to the size of the drill. 
 
 In order to cut large holes more force is obviously required than can be imparted by the method 
 just described, instead of which a brace, not very dissimilar to that used by carpenters, is employed, 
 and the drill itself is fitted as a boring-bit ; but with this difference in the mechanical arrangement, in- 
 stead of the stock remaining stationary, we have in this case a long tapering spindle, which being noth- 
 ing more than a continuation of the brace, is necessarily carried round at the same time, and the motion 
 becomes continuous. The upper part of this spindle works in an iron or steel plate, which is attached 
 to the under side of the beam, called the drill-beam. One end of this beam turns upon a transverse pin, 
 between two uprights, pierced with various holes, to allow facility of fixing it by means of the pin at 
 different elevations. The other end of the beam traverses between two uprights, and carries a heavy 
 weight, which acting as a lever necessarily keeps the drill to its work, and the point of the drill being 
 placed upon that part of the metal to be bored, the brace is revolved by the hand of the workman. 
 
 The shank of the drill should be accurately fitted in the brace, and the apparatus is generally so ar- 
 ranged that the work may be held in a strong bench-vice during the process. 
 
 The difficulty of applying a press or lever drill in confined situations appears to have been very gen- 
 erally felt. In Bergeron’s Manuel du Tourner, there is a plan of a brace worked by a pair of bevel- 
 wheels, and Mr. George Rennie, in the last edition of Buchanan on Mill-work and other Machinery, has 
 given two views of a portable drill, invented by Messrs. Nasmyth, Gaskell, &' Co., of Manchester, which 
 consists of a cast-iron frame, carrying an upright drilling spindle, the top of which is formed into a 
 screw, so that it may be raised or depressed by a handle-wheel, while the requisite revolving motion is 
 imparted to it by two small bevel-wheels. When required to drill a hole in any piece of machinery, 
 it is first of all set in its proper place ; after this is done the handle or small fly-wheel is turned round 
 for working the drill, and by a slow revolving motion given to the upper handle, communicating by 
 means of the screw, the drill while working is made gradually to descend. 
 
 * The contrivance we have now to describe is, we are informed, the invention of a practical mechanic, 
 then in the employ of Mr. Hague, of London. The distinguishing feature of this tool is the introduction 
 of a ratchet-wheel and click, which obviate the necessity of turning the brace completely round, so that 
 the effective power of the workman is constantly acting at the greatest advantage. Big. 8432 shows 
 an elevation of the complete tool. Fig. 
 
 3483 is a section of the same ; and Fig. 
 
 3434 the ratchet with its appendages, 
 and the arm separately. It is composed 
 of two parts : the first distinctly shown 
 in the sectional view, and distinguished 
 by the letter a, which is simply an elon- 
 gated nut ; the second is a circular piece 
 of wrought-iron, terminating in a square 
 threaded screw h, and working into the 
 aforesaid nut a. The combined length 
 of these two, which constitute the prin- 
 cipal part of the tool, as shown in Fig. 
 
 3432, may be lengthened or shortened 
 at pleasure, by means of a nut a. The 
 bottom piece b has a square hole, slightly tapered, cut in its extremity, and in a direction with its axis 
 for receiving the drill f The handle or third portion of the tool, shown separately in Fig. 3434, fits on 
 to b, for which purpose a square hole is cut in it as shown at e ; the handle has a portion of it at one 
 end cut out to receive the ratchet and its appendages, as is apparent from inspection of the figure, and 
 is kept in its place by the ring or cap, shown in section at m m, Fig. 3433. The action of the ratchet- 
 vheel is plainly restrained to one direction by means of the click g and spring h, so that when the han- 
 dle is moved with a backward pull, the drill does not move. 
 
 In working, the conical point of the brace is placed under a temporary framing of cast-iron; the tool 
 being thus fixed is set in motion by means of the handle c, the drill being pressed down when neces- 
 sary, or, in technical language, “ kept to its work,” by unscrewing the upper portion or nut a, by means 
 of a piece of pointed iron which enters a hole cut for that purpose, and obviously urges the drill down- 
 ward. 
 
 Such, with some unimportant modifications, is the form in which this very useful implement has till 
 recently been constructed. Its advantages may be enumerated in few words : it requires less exertion 
 than any form of brace or drill-stock previously introduced, and it performs its work with greater accu- 
 racy. It is not, however, free from defects ; the ratchet-wheel, click, and spring, are liable to derange- 
 ment, and require to be frequently replaced, and the noise which is produced in working the instrument 
 is far from agreeable. These objections are obviated by an arrangement recently proposed by Me 
 Shanks of Johnstone, England, which, we think, will be found in every respect superior to the old form, 
 and only requires to be more generally known to insure its preference and adoption. The principal 
 peculiarity of Mr. Shanks’s hand-drill is the substitution of a spiral steel band, or clutch, embracing the 
 
 3432. 3433. 
 
732 
 
 TOOLS. 
 
 drill-stock, and acting upon it by friction for the more complicated combination of ratcliet-wlieel, click, 
 and spring. Fig. 3435 shows an elevation, and Fig. 3486 a section of this improved form of the tool, 
 a is the hallow nut for adjusting the drill to different lengths, b the screw fur feeding the drill, c the 
 handle of the same form, and worked in the same manner as that already described, but made with a 
 cylindrical socket c', which embraces the spiral riband k, and of which Fig. 3437 is a detached view 
 This spiral riband or clutch iti bored truly cylindrical to fit the drill-stock e, and rests without being 
 fixed upon a collar at the lower end cf the stock ; it is fixed to the upper part of the socket c' by the 
 screw l, and the washer m secures all these parts. 
 
 3435. 343G. 
 
 3437. 3438. 
 
 The mode in which the tool works will be sufficiently obvious from the above description and an ex- 
 amination of the section, Fig. 3436. When the handle c is turned in the direction in which the drill f 
 cuts, the clutch k by its friction firmly embraces the drill-stock e, and turns the drill, however great the 
 resistance may be. When the handle is returned the clutch relaxes and slips upon the stock, thereby 
 preventing the return of the drill. 
 
 The class of tools w T kich come within the general description of rose-bits, countersinks, wideners, or 
 broachers, is far too numerous to admit of any specific description in an article like the present. Some 
 are intended partially to enlarge a hole previously drilled, others to do so throughout its entire depth. 
 M. Lenseigne, a French mechanician, has made a great and decided improvement in the form of his 
 broaches. It is a well-ascertained fact that pentagonal broaches do not perform their work very accu- 
 rately, more especially when applied to enlarge a hole drilled through a thin plate of metal. The mo- 
 tion of the brace has a tendency to render the hole sensibly larger at the mouth. To correct this defect 
 some workmen turn the broach truly cylindrical and then remove a portion of two sides with a file, as 
 is showm in the sectional view, Fig. 3438 : the part a, which is a segment of a circle, bears against the 
 sides of the bole, and serves as a conductor, and whilst the acute angular edge b quickly removes the 
 material, the obtuse angle c, which follows, corrects any inequality of cutting. This form of broach is 
 unquestionably preferable to any previously introduced ; nevertheless it has this defect: if a chip of 
 metal gets between the round part a of the broach and the side of the bole, the angular edge b is 
 necessarily thrust forward, and the truth of the work is destroyed. To avoid this difficulty, M. Len- 
 seigne gives to his broaches the form shown in section in Fig. 3439. Here there are three segments of 
 a cylinder which serve as guides, and the metal i9 removed by the obtuse angular edges. A tool thus 
 formed cuts nearly as fast and much more accurately than that shown in Fig. 3438 ; it also possesses 
 the advantage of being more easily made than those which are either pentagonal or hexagonal. 
 
 We have now to consider the method of cutting a screw or spiral thread upon any cylinder of metal 
 by a manual operation. Before describing the tools by w 7 hich this effect is produced, we propose to lay 
 before the reader a brief analysis of Mr. Joseph Whitworth’s excellent and thoroughly practical essay 
 on a Uniform System of Screw Threads, as applied to bolts and screws, used in fitting up steam-en- 
 gines and other machinery. The difficulty of ascertaining the exact pitch of any particular thread, es- 
 pecially when it is not a submultiple of the common inch measure, occasions extreme embarrassment, 
 au evil which would be completely obviated by uniformity of system, the tnread becoming constant for 
 a given diameter. The same principle would also supersede the costly variety of screwing apparatus 
 required in many establishments, and remove the confusion and delay occasioned thereby ; it w T ould 
 likewise prevent the waste of bolts and nuts which is at present unavoidable. 
 
 It does not appear that any combined effort has been, hitherto, made to attain so desirable an object ; 
 as yet there is no recognized standard, and this will cease to be a matter of surprise when it is consid- 
 ered that any standard must, to a great extent, be arbitrary. On the one hand, it is impossible to de 
 duce a precise rule from mechanical principles, or from any number of experiments ; and, on the other, 
 the nature of the case is such that mere approximation would be unimportant and unsatisfactory, ab- 
 solute identity of thread being indispensable. To how great an extent the choice of thread is arbitrary 
 will appear from a cursory consideration of the principles affecting it. Without attempting to discuss 
 these in detail, which would be foreign to the present purpose, it may he interesting to notice the gen- 
 eral outline and bearings of the subject. 
 
 The use of the screw-bolt is to unite certain parts of machinery in close and firm contact, and it is 
 peculiarly adapted for this purpose by the compact form in which it possesses necessary strength and 
 mechanical power. The extreme familiarity of the object tends to prevent the observation of its pecu- 
 liar fitness, yet among all the applications of mechanics there is, perhaps, no instance of adaptation 
 more remarkable. The ease with which distinct parts of machinery can be united, the firmness of the 
 union, and the facility with which they may he separated, are conditions of the utmost importance, 
 Which by no other contrivance could be combined in an equal degree. 
 
TOOLS. 
 
 73S 
 
 While, however, the utility of the screw in this application is abundantly obvious, it is by no means 
 evident what may be the precise formation most advantageous under all circumstances. No exact data 
 of any kind can be obtained for calculation, and the problem will be found to be capable only of ap- 
 proximate solution. 
 
 The principal conditions required in the screw-bolt are power, strength, and durability — the latter 
 having reference to the wear occasioned by frequent fixing and unfixing. But none of these conditions 
 can be reduced to any definite quantity. We cannot, for example, determine the exact amount of pow 7 er 
 necessary to draw the parts of a machine into due contact, of the precise degree of strength which may 
 suffice for resisting the strains to which they may be exposed. Hence we cannot lay down any rule 
 for determining the diameter of the screw-bolt required for a given purpose. Practical men can judge of 
 the proper size with considerable accuracy, but they have no means of ascertaining it with absolute 
 precision. 
 
 If the diameter be given, and it be required to find the proper thread, the nature of the question is 
 not essentially altered. The amount neither of power nor of strength, nor indeed any other condition, 
 is thereby determined. A certain limit is assigned, but within that limit the proportions of strength 
 and power, <fcc., may vary indefinitely according to the actual formation of the thread. There are three 
 essential characteristics belonging to the screw thread, namely, pitch, depth, and form. Each of these 
 may be indefinitely modified independently of the others, and any change will more or less affect the 
 several conditions of power, strength, and durability. The mechanical power of the screw clearly de- 
 pends on the pitch, which, for a given diameter, determines the angle of the inclined plane, and on the 
 form of thread which regulates the direction in which the force applied w'ill act. The strength of the 
 screw, as regards the thread, varies with each of the three characters ; in the centre part being as the 
 area, it is little affected, except by change of depth. The durability of the thread also depends chiefly 
 on its depth, and the proper degree of the latter is determined principally with reference to this condi- 
 tion. In the selection of the thread considerable latitude of choice will be found to prevail with refer- 
 ence to all the characteristics ; therefore no definite rule can be given for determining any one of them. 
 It may be manifest that particular threads are too coarse or too fine, too deep or too shallow, but there 
 are clearly intermediate degrees, within which the choice of thread, like that of the diameter, is arbi- 
 trary, and must be guided rather by discretion than by calculation. 
 
 The mutual dependence of the several conditions required in the thread may be noticed as having a 
 tendency to perplex the choice. Thus, increase of power, according to a known law, is necessarily at- 
 tended with diminution of strength, and the square thread which has the advantage in respect of power 
 is proportionally weaker than the angular thread. A fine thread loses in strength while it gains me- 
 chanically as compared with one that is coarser ; and deep threads, while they are more durable than 
 shallow, materially detract from the strength of the bolt. 
 
 The selection of the thread is also affected by the mutual relation subsisting between the three con- 
 stituent characters of pitch, depth, and form. Each of these, as already observed, may be separately 
 modified ; but practically no one character can be determined irrespectively of the others. The pitch 
 of the square thread is usually twice that of the angular, for the same diameter, to retain similar pro- 
 portions of power and strength. Coarse threads should be deep as compared with fine to provide 
 against the wear from friction, and a coarse angular thread will require additional depth, not only to 
 preserve the due proportion of power, but also to prevent the longitudinal strain from being thrown 
 too much sideways on the nut. Hence each character acts as a limit to the variation of the others, and 
 in some instances, that is, in the case of certain diameters, it will be found that the leading considera- 
 tions in fixing one character is the resulting effect on another. Thus, in some of the smaller sizes 
 screws, the pitch is determined principally by reference to the depth, a coarser thread being objectiona 
 ble, because the extra depth would obviously tend to weaken the centre part of the bolt, while the 
 necessary shallowness of a finer thread would render it too liable to w r ear with friction. 
 
 The proportionate strength of the thread and centre part of the screw is regulated mainly by the 
 depth of the nut, which is usually of the same measure as the diameter of the bolt. Assuming this 
 dimension as fixed, the proportion of strength between the two parts will necessarily vary with the 
 different characters of thread, and more particularly with the depth. The centre part not being liable 
 to wear, while the thread is obviously subject to friction and accidental injury, the original proportion 
 of strength ought to be considerably in favor of the latter. 
 
 Such being the variety and vague character of the principles involved in the subject, a corresponding 
 degree of latitude might naturally be expected in their practical application. Accordingly we find, 
 instead of that uniformity which is so desirable, a diversity so great as almost to discourage any hope 
 of its removal. The only mode in which this could be attempted with any probability of success would 
 be by a sort of compromise, all parties consenting to adopt a medium for the sake of common advan- 
 tage. The average pitch and depth of the various threads, used by the leading engineers, would thus 
 become the common standard, which would not only have the advantage of conciliating general con- 
 currence, but would, in all probability, be nearer the true standard for all practical purposes than any 
 other. 
 
 Some years ago Messrs. Whitworth & Co. altered the threads of their screwing tackle on this princi- 
 ple, and the result of the experiment has proved abundantly satisfactory. An extensive collection of 
 screw-bolts was made from the principal workshops throughout England, and the average thread care- 
 fully observed for different diameters. The 4-, 1, and 1-J inch were particularly selected, and taken 
 as fixed poinls of a scale by which the intermediate sizes were regulated, and the only deviation made 
 from the exact average was such as was absolutely necessary to avoid the great inconvenience of small 
 fractional parts in the number of threads to the inch. The following table shows the number of threads 
 to the inch, standard measurb, for each diameter. 
 
,34 
 
 TOOLS. 
 
 It ■will be observed that above one inch diameter the 
 same pitch is used for two sizes. This was unavoidable 
 without introducing small fractional parts ; moreover, the 
 economy of screwing apparatus is promoted by repetition 
 of the thread. 
 
 Further, it is important to remark that the proportion 
 between the pitch and the diameter varies throughout the 
 entire scale. Thus the pitch of the \ inch is one-fifth of the 
 diameter ; that of the 4 inch, one-sixth ; of the 1 inch, one- 
 eighth ; of the 4 inch, one-twelfth ; of the 6 inch, one-fif- 
 teenth. It is obvious that more power is required as the 
 diameter increases : but this consideration alone will not 
 account for the actual deviation, which is obviously much 
 less than it would be if the scale were calculated mathe- 
 matically with reference to the power required. The ne- 
 cessary amount of power must be determined in relation 
 to the muscular force of the human arm, aided by the lever- 
 age of the screw-key. Now in the case of smaller screws, 
 there is a considerable excess of force, and consequently of 
 power. Again in the larger we discover a deficiency of 
 power, for with all the leverage that can generally be ap- 
 plied, it requires the united force of several men to fix a 
 bolt of six inches diameter. Hence it is evident that at the two extremes of the scale the amount of 
 power required is not the leading consideration in determining the pitch of the thread, and in the smaller 
 sizes the necessary depth of a coarser thread, as already observed, would too much weaken the centre 
 jrart of the screw. It may also be mentioned that coarse threads would render small screws apt to 
 work loose for want of sufficient hold to prevent the effect of jarring ; and, on the other hand, finer 
 threads on large bolts, besides being w T eaker, and consequently less durable, might render it a matter 
 of difficulty to unfix them when occasion required. 
 
 It may, perhaps, be necessary to remark that the threads, of which the preceding table shows the 
 average, are used in cast as well as wrought-iron, and this circumstance has, doubtless, had the effect 
 of rendering them somewhat coarser than they would have been if restricted to wrought-iron. The 
 variation in depth among the different specimens, before alluded to, was found to be greater propor- 
 tionally than in pitch. The angle made by the sides of the thread will afford a simple and convenient 
 expression for the depth. The mean of the variation of this angle in one-inch screws was found to be 
 about 55°, and this was also very nearly the mean of the angle in screws of different diameters. As 
 it is obviously desirable that this angle should be constant, more especially with reference to general 
 uniformity of' system, the angle of 55° has been adopted throughout the entire scale ; a constant pro- 
 portion is thus established between the depth and pitch of the thread. In calculating the former, a 
 deduction must be made for the quantity rounded off, amounting to one-third of the whole depth— that 
 is, one-sixth from the top, and one-sixth from the bottom of the thread. Making this deduction, it will 
 be found that the angle of 55° gives for the actual depth rather more than three-fifths, and less than 
 two-thirds of the pitch. The precaution of rounding off is adopted to prevent the injury which the 
 thread of the screw and that of the taps and dies might sustain from accident. 
 
 Two descriptions of tools are employed for cutting screws by hand ; namely, the screw-plate and the 
 screw-stock, with movable dies. The first, and doubtless the most ancient form, is simply a flat plate 
 of steel, assuming the shape of a file, having a tang and handle at one or both ends ; in this plate are 
 one or more series of graduated screwed holes, so that by passing the bolt or pin successively through 
 several a finished screw is obtained. This form of tool, however modified in its construction, is obvi- 
 ously imperfect, and but rarely used except for screws under § inch diameter. 
 
 The first decided improvement with which we are acquainted is due to Mr. Peter Keir, who intro- 
 duced a cutter, let into a groove sunk in one of the dies, which follows the lead obtained by the dies, 
 and deepens the thread. This arrangement is more especially applicable to square-threaded screws. 
 
 In 1828, Mr. J. Jones submitted to the Society of Arts of London an improved form of scr.ew-stock 
 and tap, for which he received the thanks of the society. In this case, also, a cutter is used, secured 
 by clamps on the face of the screw-stock, which necessarily follows the. lead obtained by the dies, and 
 completes the screw in an expeditious manner. Thq altered form of tap is a combination of the taper 
 and plug tap, the part towards the point being conical, and the upper part cylindrical. The threads 
 are rounded off both at top and bottom, and the tap is fluted with four or more rectangular grooves, 
 one side of which is in a line with the centre, thus giving, in a cross section of the tap, a form some- 
 what similar to a ratchet-wheel. About one-third of the threads have their tops filed down to diminish 
 the quantity of surface in contact, by which much labor is saved, as the greater part of the power re- 
 quisite for screwing in the usual way is expended in overcoming the friction, and not in cutting away 
 the superfluous metal. This form of tap answers perfectly well for nuts not exceeding one incli and a 
 quarter, but for those of larger size, as two or three inches, it is advisable to insert a cutter in the body 
 of the tap just at the part where the cone terminates, by which nearly the whole of the metal is cut 
 out, and the upper or plug part of the tap has nothing to do but to equalize and smooth the thread. 
 
 In 1838, M. Gouet proposed a new form of screw-stock with four dies, two of which were conductors 
 or guides, and the other two acted as a screw-cutting or chasing tool. In the Bulletin de la Societie 
 Industrielle de Mul house, we find a description of two forms of screw-stoqjk, and an expanding tap by 
 M. Lamoriniere. The first is composed of three dies, two of which are of tempered steel, and the third 
 of wood, intended merely to serve as a conductor. The second has four dies, very narrow and directly 
 opposite to each other, which are made to approach by means of a circular plate, holloaed in an ellip- 
 
 Diameter 
 in inches. 
 
 Threads to 
 the inch. 
 
 Diameter 
 in inches. 
 
 Threads to 
 the inch. 
 
 3 
 
 TF 
 
 24 
 
 2 
 
 44 
 
 i 
 
 20 
 
 n 
 
 4 
 
 IB 
 
 18 
 
 24 
 
 4 
 
 3 
 
 8 
 
 16 
 
 21 
 
 H 
 
 1 
 
 7B~ 
 
 14 
 
 3 
 
 3-J- 
 
 i 
 
 12 
 
 si 
 
 H 
 
 & 
 
 8 
 
 11 
 
 H 
 
 34 
 
 4 
 
 10 
 
 3f 
 
 o 
 
 7 
 
 9 
 
 4 
 
 3 
 
 1 
 
 8 
 
 44 
 
 -B 
 
 n 
 
 7 
 
 44 
 
 - B 
 
 H 
 
 7 
 
 4 
 
 2J 
 
 it 
 
 6 
 
 5 
 
 2J 
 
 14 
 
 6 
 
 54 
 
 9 3 . 
 
 - 8 
 
 it 
 
 5 
 
 5i 
 
 
 H 
 
 5 
 
 5f 
 
 24 
 
 it 
 
 44 
 
 6 
 
 24 
 
TOOLS. 
 
 735 
 
 3440. 
 
 tical shape, and its circumference cut into teeth. With regard to the expanding screw-tap the. object 
 of the inventor appears to have been to dispense with a series of taps of different sizes, to cut rather 
 than press out the metal, and to allow sharpening on a grindstone when the cutting edges become im- 
 paired. M. Waldeck also invented a screw-stock with a series of cutters, which produced either angu- 
 lar or square threads, and the same mechanician subsequently introduced further improvements with 
 regard to taps. The screw-stock invented and patented by Mr. Joseph Whitworth, of Manchester, next 
 claims our attention. Of this tool there are two forms ; the first is rather complicated : the dies, of which 
 there are three, work in as many eccentric curves sunk in a metal disk, whose exterior edge is cut into 
 teeth in the manner of a tangent-wheel, and worked by an endless screw, the action of which necessa- 
 rily causes the dies either to approach or recede from a common centre. 
 
 This tool cuts the metal with great rapidity, requires but little exertion, and produces very excellent 
 screws. The principal objection to it is, that the complication of its parts, and the wear and tear of the 
 tangent-wheel render frequent repair necessary, more especially in the hands of careless or indifferent 
 workmen. 
 
 The second, or guide screw-stock, is entirely new in form, and not liable to the same objection ; more- 
 over, it is alleged by the inventor that it will cut a screw scarcely inferior to that obtained in a slide- 
 lathe from a true guide. The thread produced is not only true, and of the exact pitch required, but 
 . perfectly formed throughout, being cut clean, without distortion of the metal. 
 
 In all these respects the advantage of the guide over the common screw-stock is remarkable. The 
 latter will not cut a screw in any degree perfect ; the thread, besides being irregular, is never of the 
 right pitch ; it is also more or less swollen by the violence done to the metal, so that the diameter of 
 the screw is frequently found to exceed that of the blank-bolt in which it is cut. These defects are 
 attended with the most serious practical inconvenience ; they frequently render it extremely difficult to 
 obtain a fit between the screw and the nut, and consequently occasion a considerable sacrifice both of 
 time and labor. They necessarily impair, in a very great degree, the efficiency of the screw-bolt, which 
 cannot possess either the strength or mechanical power which it would have if the thread were cut 
 clean and true. 
 
 The defects in question are variously modified according to the size of the master-tap used in cutting 
 the dies. If they have been cut by a master-tap double the depth of the thread, larger in diameter 
 than the bolt to be screwed, they will act very well at first, and the thread will be started true, but, 
 as the operation proceeds, they become altogether unsteady and uncertain in their action. If, on the 
 other hand, they have been cut by a master-tap of the same size as the bolt to be screwed, the thread 
 is made out of truth in its origin. They first touch the bolt only on the extreme 
 point of their outer edges, as shown in Fig. 3440, a being the die, and b the pin or 
 bolt. Further, they have neither sufficient guide nor steady abutment till the oper- 
 ation is on the point of completion. It is not unusual to employ a master-tap of an 
 intermediate size. In this case, however, it is obvious that the dies will combine in 
 a modified degree the defects peculiar to each of the cases already mentioned. In 
 the guide-stock this perplexity is entirely obviated, and the dies act with full advantage from the com- 
 mencement of the operation to its conclusion. They are cut by a master-tap double the depth of the 
 thread, larger in diameter than the screw-blank ; while their general form and the direction in which 
 they are moved forward, are 'such as to preserve their cutting power, and steadiness of action, undi- 
 minished to the full depth of the thread. 
 
 The plan of the guide-stock will be easily understood from Fig. 3441. The interior of the stock is 
 shown in dotted lines through the top-plate a, which is fastened by the screws b b' b" ; c is a stationary 
 or fixed die; dd' are moving dies simultaneously brought up 
 by a piece e, sliding in a recess in the stock, and bearing with 
 a distinct incline, as shown by dotted lines, against the back r 
 
 of each die. The piece e terminates with a square-threaded f< _ -J , 
 
 screw e', and is drawn up by a nut f on the outside of the &Eggj 
 stock. The dies having been cut by a full-sized master-tap, as 
 already mentioned, the curve made by their outer edges is that 
 of the blank-pin or bolt they are intended to screw. Hence, 
 in starting the thread they bear at all points of the common 
 curve, and the impression made by indentation is an exact copy of the thread of the die. The parts in- 
 dented serve as a steady guide to the dies in cutting round the blank-pin. A groove in the stationary 
 die facilitates the operation. Four cutting edges are brought into action, at points of the circumference 
 nearly equidistant ; so that by little more than a quarter turn, the thread is completely started round 
 the pin, and the difficulty involved in the operation, by the common screw-stock, is entirely removed. 
 
 After the thread is started, the fixed die serves principally as a guide and abutment for the others. 
 The moving dies are peculiar both in regard to their form and direction, which depend on the piston of 
 the arc in the shank of the die. The two sides have each a different inclination to the arc. As the die 
 moves forward one side becomes prominent towards the screw-bolt, and its cutting edge continues in 
 contact with the thread, till it is cut to the full depth required. The prominent sides of the moving 
 dies are those turned towards each other. 
 
 The direction of the common die in screw-stocks, of the old form, is necessarily towards the axis ot 
 the screw-bolt. In the guide-stock the direction of the moving dies is that of two planes meeting be- 
 yond the centre of the stock, in a line parallel to the axis gf the screw-bolt, and considerably behind it. 
 
 This direction is determined by reference to the change which takes place in the relative position of 
 the screw-bolt as the thread is cut deeper. One of the three dies being stationary, there must necessarily 
 be a constant change in the position of the screw-bolt in relation to the two others, the effect of which, 
 if nut counteracted, would be to deprive the cutting edges of the requisite prominence ; but by giving 
 them the direction before mentioned, the proper degree of prominence is secured, notwithstanding the 
 
 
 3441. 
 
736 
 
 TOOLS. 
 
 change of position, and the latter when combined with the eccentricity of the dies, so far from being 
 any impediment to their action, materially assists it. The newly formed thread is thereby kept in con- 
 tact with the dies, for some distance behind their cutting edges, affording them the same kind of sup 
 port throughout the operation which they have at the commencement ; when, as already observed, the 
 curve made by their outer edges is coincident with that of the screw-blank. This continued support, 
 which is necessary to steady their action, could not be obtained without a change in the position of the 
 screw-bolt. They would otherwise acquire too much clearance as they form the thread deeper, and 
 their cutting edges would be apt to dig. 
 
 The steadiness of the guide-stock, and its easy action in screwing, are equally remarkable. In using 
 it, not one-half the force consumed by the common stock is required. The inner edges of the moving 
 dies, which principally act in cutting out the metal, are filed olf to an acute angle; this enables them 
 to cut with extreme ease, and without in any degree distorting the thread, while they take off shavings 
 similar to those cut in the lathe ; their action in cutting is in effect the same as a chasing-tool, to which 
 indeed they bear an obvious resemblance in form, and they may be sharpened on a grindstone in the 
 same manner. 
 
 A practical difficulty has hitherto attended the use of the screw-stock, arising from the wear of the 
 taps and dies. The tap becomes less in diameter, and consequently taps the hole too small, while the 
 opposite effect takes place with the dies, which, being unable to cut a full-sized thread, leave the screw 
 too large. The only mode of counteracting this two-fold error, so as to obtain a fit between the screw 
 and the nut, is by forcing the dies forward till they have reduced the diameter of the screw a propor- 
 tionate quantity, and from what has been before observed, it is manifest that this cannot be done in the 
 case of common dies, without injury to the thread. In using the guide-stock, on the contrary, it is 
 attended with no disadvantage, and lest the diameter of the screw should inadvertently be reduced 
 more than necessary, figures are stamped on the sides of the nut/, to indicate when the thread is full. 
 
 We have now to describe another screw-stock. This tool is constructed on the principle of the ordi- 
 nary screw-stock, with such additions and alterations as appeared necessary. The principal objection 
 to the old form is, that the metal is rather pressed out than cut, at the expenditure of much force ; in 
 that now under consideration, one die acts as a guide, and the other as a cutter, by which arrangement 
 not only is a perfect thread produced, but the tenacity of the metal is preserved and less power em- 
 ployed. 
 
 Figs. 3442 and 3443 show Mr. Bodmer’s improved screw-stock, with the lid removed in a plan and 
 longitudinal section ; a a ' is the box made either of steel, wrought, or cast iron ; b the vibrating tool or 
 cutting-die, which is fixed in the die-holder c, in such a manner as to accommodate itself to the inclina- 
 tion of the thread when the die begins to cut on the surface. The die may also be a perfect fit in the 
 die-holder c, but in that case it must be cut to a larger diameter than the screw itself would require, as 
 usually done in common stocks ; d is the guide-die recessed into the stock a a', and which may be bored 
 out to the full diameter of the bolt or pin to be screwed, or tapped in the ordinary manner. The guide- 
 die d is prevented from turning by a small key e ; the screw/, in the die-holder c, is not only the handle 
 or lever by which the stock is worked, but also advances the cutting-die b as the operation proceeds. 
 The cutting die-holder c is recessed into the stock, in a manner similar to d, and has as much room at 
 x and x as is necessary to allow that part of the cutting-die which, when the stock is turned in the op- 
 posite direction would drag, to recede out of the thread so as to clear the thread and particles of metal 
 cut out during the operation, by which arrangement the cutting-die will preserve its keen edge. Sup- 
 pose the operation of screwing to have been commenced at the bottom of a pin, and the stock arrived 
 at the top ; the handle or screw / will require to be advanced a little, and then the stock is ready to 
 work in the opposite direction. It is evident that the moment the handles ff are pulled by the work- 
 man, the die will bite on that side which is moved deeper by the pull, and recede out of cut on the 
 opposite side ; it will therefore act and cut like a tool in a lathe or planing machine, and preserve its 
 keen edge much longer, and remove filaments of metal much more easily than dies constructed in the 
 ordinary way. 
 
 344‘i. 3445. 3444. 
 
 Fig 3444 is an end view of the stock; Fig. 3445 a ground plan and an end view of the cutting die- 
 holder, and Fig. 3446 the lid of the stock fitting the bevel or half V grooves of the same ; Fig. 3447 is 
 a plan and section of the guide-die d, and Fig. 3448 shows a mode of regulating the play or motion of 
 the cutting-die b, by means of set-screws. 
 
 ' Fig. 3449 is a ground plan, and Fig. 34^0 a section of a stock with two cutting-dies moving in a 
 lateral direction; a a' is the stock or frame; bb' the handles or set-screws, acting upon the dies cc', 
 which are perfect fits in the stock, and against which the cutting-dies dd' slide laterally. These dies 
 are confined between two plates which are screwed or riveted to the stock in the ordinary manner. It 
 is evident that the two cutting-dies dd', when tightened up against the piece which is to be screwed. 
 
TOOLS. 
 
 737 
 
 will recede in the contrary direction to that of the pull, as much as there is space left between the dies 
 and the side of the stock, and in so doing will operate in the manner already described with reference 
 to the vibrating dies. 
 
 3450. 3449. 
 
 Fig. 3451 shows a longitudinal and end view of one of these taps. After having been finished to 
 nearly the right measure in the screwing lathe, the taps are subjected to the operation of a mechanism 
 in a tap-cutting lathe, by means of which the convolute form is given. 
 
 3451. 
 
 The advantage of this construction of tap is evident, because not only is the top of the thread eased 
 in a convolute form, as usually done by hand, but likewise the bottom ; the sides of the thread also are 
 tapered, or relieved, in the same proportion, so that the tap cuts like an ordinary turning-tool, instead 
 of making its way through the metal by sheer pressure. 
 
 The annexed table indicates the number of threads per 
 inch both for angular and square threads. 
 
 To describe, within the limits of a brief article, the various 
 tools used among the different classes of turners is manifest- 
 ly impossible. They are so infinitely diversified both in 
 form and size, according to the necessities, the ingenuity, 
 and frequently, perhaps, the prejudice of those who use 
 them, that a volume would scarcely suffice to do justice to 
 the subject. 
 
 Gravers, triangular, square, round, pointed, heel or hook, 
 and screw tools, with various other nameless sorts, the con- 
 trivance of individual skill, are used in turning hard bodies, 
 such as bone, ivory, and the metals. 
 
 The graver is made from a square bar of steel cut off by 
 an oblique plane at the end, which forms a lozenge or dia- 
 mond face, and produces two inclined edges, at two of the 
 flat sides of the bar ; these are inclined opposite ways, so 
 that the graver serves either for left or right hand work by 
 merely turning it one quarter round to bring up another 
 side. The point formed by the acute angle in which the 
 two inclined edges meet, is better adapted for cutting than 
 any other form, and is exceedingly strong; the flat sides 
 give it an excellent bearing upon the rest. Another conve- 
 nience of the graver is the ease with which it may be sharp- 
 ened, an object of considerable importance in turning hard 
 metal ; it only requires to be held on the grindstone at the 
 proper angle to grind the diamond face away, and thus make sharp edges with the two flat sides. The 
 graver is principally used to rough the work, its point being applied to cut grooves all over the surface 
 till it is true, and then the welved edge of the graver, or a square, or round tool, makes it smooth, and 
 of a proper figure. 
 
 Triangular and square tools are so denominated from their respective sections being of these figures 
 — they are flat at the end. The former have three cutting edges, namely, each arris in a longitudinal 
 direction ; the latter, which are principally used for turning brass, have four, that is, each arris at the 
 extremity. 
 
 Hound tools have the edges of a semicircular form, and are used for forming hollow mouldings. 
 
 The pointed tool has two inclined edges, forming a point, which cut grooves in any piece of work, or 
 its edges may be used to turn shoulders either right or left. 
 
 Heel-tools are used for turning wrought-iron, steel, and copper ; they are made with all the edges 
 already described, but the end where the edge is formed is bent, so that when it is presented to the 
 work in a proper direction, the handle is inclined upwards in such a position that the end of it will rest 
 upon the workman’s shoulder, and he holds it down firmly with both hands, the heel of the tool being 
 at the same time supported on the lathe-rest. The metals above mentioned, being of a fibrous texture, 
 turn away in a connected shaving ; the tools are therefore presented in the direction of a tangent to the 
 work, but as the drift of the work would force the tool endways, it is necessary to have a heel or angle 
 which is placed immediately upon the rest : then the long handle serves to guide and fix it, and by ele- 
 vating the end its edge cuts deeper. 
 
 Cast-iron is turned by hook-tools ; their edges are formed in various ways, but invariably very obtuse, 
 being nearly a right angle ; in turning they are held in such a position that a line bisecting the angle of 
 the edge is made to point nearly to the centre, and as the metal is usually hard and refractory, they 
 Vol. II.— 47 
 
 V-Threads. 
 
 Square Taper-threads. 
 
 Diameter 
 
 Threads 
 
 Diameter 
 
 Threads 
 
 in inches. 
 
 per inch. 
 
 in inches. 
 
 per inch. 
 
 5 
 
 77f 
 
 18 
 
 5 
 
 TF 
 
 9 
 
 3 
 
 8 
 
 16 
 
 3 . 
 
 8 
 
 9 
 
 7 
 
 TF 
 
 14 
 
 7 
 
 TF 
 
 8 
 
 4 
 
 12 
 
 4 
 
 7 
 
 y 
 
 TF 
 
 11 
 
 TB 
 
 7 
 
 5 
 
 8 
 
 11 
 
 8 
 
 7 
 
 1 1 
 
 TF 
 
 10 
 
 1 1 
 
 TF 
 
 7 
 
 l 
 
 10 
 
 f 
 
 6 
 
 1 3 
 
 TF 
 
 9 
 
 1 3 
 
 TF 
 
 6 
 
 7 
 
 F 
 
 9 
 
 7 
 
 B 
 
 6 
 
 1 5 
 
 TF 
 
 8 
 
 1 5 
 
 TF 
 
 6 
 
 i 
 
 8 
 
 i 
 
 5 
 
 
 7 
 
 
 4 
 
 H 
 
 7 
 
 H 
 
 4 
 
 if 
 
 6 
 
 1 3 . 
 
 1 8 
 
 3 
 
 H 
 
 6 
 
 n 
 
 3 
 
 M 
 
 5 
 
 if 
 
 2f 
 
 if 
 
 5 
 
 if 
 
 24 
 
TOOLS. 
 
 i 38 
 
 arc made with a hook, which, being laid over the rest, acts as a lever, and causes the edge to approach 
 to or recede from the work by merely raising or depressing the end of the handle. 
 
 Screw-tools are very important appendages to a lathe, and in many cases indispensable ; they are 
 usually made in pairs, namely, an outside and an inside tool, and the teeth of both should be so accu- 
 rately cut that on being placed together, the teeth of the one in the intervals between the teeth of the 
 other, they should exactly fit, even to tire exclusion of light. It may probably appear fastidious to 
 insist on this rigid perfection in a tool which is apparently of simple and easy construction ; a little 
 consideration, however, will show that unless the teeth, whatever be their shape, are similar in every 
 respect, it will be impossible to cut an accurate thread, since if one tooth be in the least degree larger 
 than the others, it will necessarily destroy the proportion of the thread. 
 
 Many methods have been suggested to enable the mechanic to cut his screw-tools. M. Seguier, a 
 distinguished amateur turner, recommends that a model be taken in lead or soft brass, by impression of 
 the required screw, and then to place the pattern so obtained and the blank tool back to back in a vice, 
 and with a triangular file remove the steel, until the projecting teeth exactly coincide with the model. 
 To this we object that the form of a triangular file does not agree with the shape of a screw-thread — it 
 is much too obtuse ; what is called a slitting file is certainly more suitable. With very great care and 
 dexterity in the use of the file, this method may answer, but the operation demands an aptitude and 
 precision of hand rarely attained — added to which the loss of time and risk of failure are scarcely com- 
 pensated by the probability of success. 
 
 We now proceed to explain a method very generally adopted to cut the teeth in screw-tools. A 
 piece of cast-steel is turned cylindrical, and being suspended between the centres of the lathe, is made 
 to revolve ; upon the surface of this cylinder a series of concentric and equidistant circles are cut by 
 means of a screw-tool, or a simple V-tool, which is held firmly and in a fixed position against the steel 
 cylinder. When the teeth are sufficiently raised by the cutting action of the tool, the cylinder is re- 
 moved from the lathe, and gaps or notches cut across its surface in a diagonal direction, so as to give to 
 the teeth a cutting edge. It is then hardened, and tempered to a straw-color. This is technically called 
 a hob, or hub. 
 
 The great objection to this method is, that it produces perpendicular and not inclined teeth in the 
 screw-tool. This however, is easily remedied by cutting a regular helix, instead of merely concentric 
 circles, upon the surface of the hob ; or still more readily by employing a common plug-tap, which an 
 swers the purpose perfectly well. 
 
 We will now suppose either a hob or plug-tap to be made to revolve between the centres of the lathe. 
 The workman takes a blank screw-tool, which must be well annealed, and applies its face to the re- 
 volving hob ; being careful to hold the tool very firmly, yet not to allow the hob at the commencement 
 to bite too greedily, and supplying oil to the surface of the hob or tap, which essentially assists the 
 operation. The blank tool may be held either above or below the centre of the hob. The latter is 
 shown in Fig. 3453, and is in some respects preferable to the 
 former, as it affords a better purchase for the tool. The method 
 practised in Manchester of cutting screw-tools, is in many re- 
 spects similar to that we have just described, except that it 
 requires the aid of change-wheels and a slide-lathe. Never- 
 theless, as many of the details are common to both, the obser- 
 vations we are about to make will, in some measure, apply to manual as well as mechanical power. 
 
 The first thing is to cut the hob, or hub, which is effected by a self-acting slide-rest. It is simply a 
 screw cut on the surface of a solid cylinder of cast-steel, with diagonal grooves cut across the thread ot 
 the screw to act as cutters, as shown in Fig. 3452 ; the two necks of the hob have concave holes drilled 
 in the ends to carry the centres of the lathe. 
 
 The hob is placed between the centre points of the lathe, by means of a dog or catch attached to one 
 end in the usual way-. Change-wheels are then put on to connect the mandrel or spindle with the 
 guide-screw of the lathe, and which carries along the slide-rest. The wheels are so arranged that one 
 turn of the mandrel causes the slide-rest to travel a distance exactly equal to one thread. The blank 
 which is to be cut is firmly screwed down in the tool-box of the slide-rest, and made to stand above the 
 centre of the hob, as shown in Fig. 3454. It is then pressed, by the screw of the slide-rest, against the 
 hob ; and the lathe being put in motion causes the tool to traverse along and against the hob, cutting it 
 as deep as may be thought necessary. The face of the tool, when cut, is a segment of a circle, varying, 
 of course, according to the diameter of the hob. 
 
 3452. 5343. 
 
 3454. 3455. 3456. 
 
 Fig. 3455 is a side view of the tool in this condition ; but this form is not found sufficiently economical 
 n practice, since it can only be ground and sharpened to a particular point, as to b , for when ground to 
 /, as from a to c, it ceases to cut, owing to the top of the tool being then as far from the screw to be 
 cut as the bottom. The method adopted to obviate this difficulty is to give the tool an angular instead 
 of a circular face, and this is managed in the following way : the screw-tool is removed from the slider- 
 rest, and as the hob revolves, the workman elevates and depresses the end of the tool which is in his 
 hand, so as to present different points of the face to the cutting action of the hob, until by degrees he 
 succeeds in obtaining a perfectly angular face, which allows the tool to be ground nearly or quite to the 
 bottom, with a certainty of preserving a good cutting edge. In order to fix the blank which is intended 
 
TOOLS. 
 
 739 
 
 to make an inside screw-tool, in the slide-rest, some little contrivance is necessary, the stem is usually 
 bent, and afterwards, when cut, set straight previously to hardening. 
 
 The handles of turning-tools, it may be premised, must be varied in size, according to the manner in 
 which they are intended to be held. For heavy work, more especially when the lathe is turned by 
 machinery, they must be sufficiently long to reach to the shoulder, upon which one end rests during the 
 operation of turning, besides being held by both hands of the workman at the same time. In using the 
 foot-lathe the tools are held by both hands only, and the handles are rarely more than half the length 
 required in the former instance. 
 
 The socket-handle for turning-tools, Fig. 3456, is an extremely ingenious and useful appendage to the 
 lathe, as it is equally applicable to slide-rest tools. This handle is 9 J inches long ; the brass socket a a' 
 has a longitudinal slot b b’ , which terminates at the circular hole c. This socket is confined by the steel 
 ring d d', which has at one side a steel set-screw e, and at the other a pincbing-screw f which necessa- 
 rily contracts the aperture, and consequently grips the tang of a tool placed within it. The slot b b’, as 
 well as the opening for the tang of the tool and the pinching-screw, are more clearly shown in the end 
 view. 
 
 The tool-gage is a very simple and convenient method of ascertaining whether a tool is ground oi 
 formed to the proper angle. It consists of a planed plate of metal, on whose surface there is, at one 
 end, fixed a conical steel pin, whose taper, or the angle formed by the sides of the cone with the surface 
 of the plate, is exactly that which is proper for the cutting face of the tool. The angle formed by the 
 sides of the cone and the surface of the base plate should be about three degrees. By using this gage, 
 all difficulty of forming the tools to the proper angle is at once removed. Moreover, this same gage will 
 answer for every kind of planing or turning tool of whatever size. 
 
 We now proceed to a very important practical inquiry, namely, the velocity at which tools cut most 
 advantageously for different kinds of material. 
 
 It cannot, we apprehend, have escaped the observation of such of our readers who are in the habit of 
 turning metal, that if a velocity exceeding certain prescribed limits be imparted to the material, the 
 edge of a cutting-tool applied to reduce the surface of that material is brought to a soft state and ren- 
 dered obtuse. This is an acknowledged fact, and many ingenious contrivances have been, from time to 
 time, introduced to meet the exigency, of the case, or in other words, to regulate the speed of the lathe- 
 mandrel according to the hardness and diameter of the metal or other substance to be turned. It is 
 commonly supposed that for wood the velocity cannot be too great, yet this is probably a vulgar error, 
 since if we allow the speed to pass certain limits the tool necessarily becomes hot, loses its temper, and 
 ceases to cut. Wrought-iron requires a slow motion, and cast-iron, above all, ceases to be affected by 
 the edge of the tool, unless a very slow and regular motion is preserved, as it appears to act by abrasion, 
 and actually grinds away the face of the tool. 
 
 The opinion of practical men is much divided on this point— some name from ten to fifteen feet per 
 minute as a maximum velocity, others allow thirty to forty feet, whilst others again regard this as the 
 minimum speed which should be given to cast-iron, in order to obtain the greatest effect from the tool. 
 
 For turning or boring cylinders, or indeed any substance of which the diameter is nearly equal 
 throughout, a uniform velocity fully answers the purpose, since the speed can easily be increased or 
 diminished by means of conical pulleys placed in opposite directions, as also by many other mechanical 
 contrivances* which are too familiar to practical men to require any extended description on this occa- 
 sion. Suppose, for example, we have a cylinder of wood of considerable diameter to turn, we devise 
 some lViethod to control the speed, as, for instance, by diminishing the diameter of the fly-wheel, and 
 increasing that of the pulley or mandrel-wheel ; by this means the motion is made slower, and in some 
 respects in proportion to the diameter of the material. Had the cylinder been composed of cast-iron 
 instead of wood, we should have pursued a somewhat similar course, but carried to further limits than 
 that we have just described. The facility afforded by two elongated cones, fixed in opposite directions, 
 as regards their respective diameters — the one attached to or in immediate connection with the ffy- 
 wheel, and the other on the lathe-mandrel — enables us to regulate the velocity with a precision that in 
 many operations is of the highest importance ; but it must be remembered that the advantageous effects 
 of this arrangement are limited to the circumference, or perimeter. 
 
 The back-geer lathe, Fig. 2538, p. 179, answers the purpose perfectly well for cylindrical turning. In 
 this arrangement the driving-cone b and pinion p are connected, and may either run loose or be locked 
 to the spur-wheel w, but in the former case the speed of the lathe-spindle, and consequently whatever is 
 attached to it, is greatly reduced, as indeed is manifest from inspection of the engraving ; for sujjposing 
 the spur-wheel w and pinion p to have respectively 52 and 13 teeth, and the spur-wheel h and pinion i 
 on the back-geer spindle also 52 and 13 teeth, tire ratio of speed of the driving-cone to that of the lathe- 
 spindle would be as 16 to 1 ; or, in other words, the latter would perform 1 revolution for every 16 rev- 
 olutions of the former. 
 
 M. Armengaud, a distinguished French engineer, has arranged the different degrees of velocity 
 applicable to the several mechanical operations of turning, boring, drilling, &c., in the following 
 manner : 
 
 The velocity at the circumference of the material, or of the tool for turning or planing cast-iron, should 
 be from 7 to 8 centimetres-)- per second. 
 
 The velocity of the tool at its circumference for widening or broaching cast-iron is from 4 to 5 cen- 
 timetres per second. 
 
 * Those who wish to investigate the subject will gather much information from the specification of Mr. Bramah’s patent, 
 long since expired. 
 
 + The centimetre, according to Professor Millington, is equivalent to 0-393 of an English inch, and M. Armengaud states 
 that the latter, compared with the French inch, is as 25 : 27 very nearly; that is to say, the French inch containing 27 
 millimetres, the English vuch contains only 25 mills. 4. 
 
740 
 
 TOOLS. 
 
 Diameter 
 in inches. 
 
 Revolutions 
 of spindle per 
 minute. 
 
 Diameter 
 in inches. 
 
 Revolutions 
 of boring-bar 
 per minute. 
 
 i 
 
 50 
 
 i 
 
 25 
 
 2 
 
 25 
 
 2 
 
 12-5 
 
 3 
 
 16-67 
 
 8 
 
 833 - 
 
 4 
 
 12-50 
 
 4 
 
 6-25 
 
 5 
 
 10 
 
 5 
 
 5 
 
 6 
 
 8-32 
 
 6 
 
 4-16 
 
 7 
 
 7-15 
 
 7 
 
 3-57 
 
 8 
 
 6-25 
 
 8 
 
 3125 
 
 9 
 
 5'55 
 
 9 
 
 2-77 
 
 10 
 
 5- 
 
 10 
 
 2-5 
 
 15 
 
 3-33 
 
 15 
 
 1-66 
 
 20 
 
 2-50 
 
 20 
 
 1-25 
 
 25 
 
 2 
 
 25 
 
 1 
 
 30 
 
 1-667 
 
 30 
 
 0-833 
 
 35 
 
 1-430 
 
 35 
 
 0-714 
 
 40 
 
 1-250 
 
 40 
 
 0-425 
 
 45 
 
 1-12 
 
 45 
 
 0-56 
 
 50 
 
 1 
 
 50 
 
 0 5 
 
 60 
 
 0-834 
 
 60 
 
 0-417 
 
 70 
 
 0-716 
 
 70 
 
 0-358 
 
 80 
 
 0-626 
 
 80 
 
 0-313 
 
 90 
 
 0-554 
 
 90 
 
 0-278 
 
 100 
 
 0-50 
 
 100 
 
 0 25 
 
 The velocity of cast-iron, turned by a hook-tool, held 
 and guided by the hand of the workman, to finish or 
 complete, is 12 centimetres. 
 
 For iron turned by means of the slide-rest, the velo- 
 city at the circumference of the work is about 14 cen- 
 timetres. When the metal is turned by hand-tools, the 
 speed at its circumference is from 18 to 20 centime- 
 tres to rough out, and from 28 to 30 centimetres to 
 finish. 
 
 The difference of velocity of the work or the tool 
 when the turning is effected mechanically or by the 
 hand, is deduced from the obvious fact, that in the for- 
 mer case the contact between the tool and the work is 
 constant and invariable, whilst in the latter it is inter- 
 mittent. 
 
 The foregoing velocities are equally applicable to 
 drills or cutters in boring machines. 
 
 The lateral progress of the tool varies according to 
 the power of the machine ; it is in general from 4 to -J- 
 of a millimetre for each revolution of the work, never- 
 theless it should be less for drills. 
 
 The annexed table indicates the average degree of 
 speed, as well for turning as boring. 
 
 If we have occasion to turn a plane surface accu- 
 rately true, the motion of the lathe-mandrel, or what 
 is the same thing, the substance affixed to it, requires 
 to be accelerated or retarded in a ratio proportioned 
 to the progress of the tool, either to or from its 
 centre ; then that portion of the plane where the 
 tool takes effect would pass its edge always at the same velocity; and if a proper speed be obtained 
 in the first instance not only will the tool preserve its originally keen edge for a very considerable time 
 uninjured, but the surface produced by its action would be nearly perfect. This control and command 
 of the movement obviously require that it be continuous ; since if the lathe be stopped, a mark, or false 
 cut, as it is termed, will be the unavoidable result. 
 
 Under ordinary circumstances, regular motion in surface-turning is not only prejudicial in relation to 
 its effects, but it also involves great waste of time. We will suppose that a speed suitable for the cir- 
 cumference and the proximate parts is obtained, it is evident, as we approach the centre, the rotary 
 movement becomes less effective ; until at length near the centre it produces little or none, and the 
 work does not proceed at all. The reason of this is obvious ; the velocity continues unaltered, while 
 the diameter of the material is progressively reduced. It is also manifest as an inevitable consequence 
 to uniform motion in surface-turning, that presuming a suitable velocity be communicated when the tool 
 is at the greatest distance from the centre of rotation, if it be made to advance regularly towards the 
 same point, similar uniform speed being continued, the cutting edge of the tool would 
 not, on its arrival at the centre, be more deteriorated than if the velocity had been in- 
 creased in a proportionate ratio to its progress towards the centre. This, we believe, 
 is an admitted fact by competent judges ; but it must be remembered there would be a 
 sacrifice of nearly one-lialf of the time employed. This statement, extraordinary as 
 it may appear, is nevertheless susceptible of mathematical demonstration, a mode of 
 proof which, we presume, few will feel inclined to dispute. Let the parallelogram, a 
 bed, Fig. 3457, represent the time that would be required to turn a surface. Draw 
 the diagonal line b c ; bisect the line a c at e, e c at g, and g c at i ; then draw the lines 
 ef, g h, and ij parallel to a b. 
 
 Let c represent the centre, a c equal the radius, and a b equal the circumference, or time of one revo- 
 lution at its greatest diameter; therefore, the lines ef, g h, and ij, will also represent their circumfer- 
 ence, or time of one revolution at their respective radii at eg and i; and as the lines a b, ef, gh, and 
 ij, are one-half the length of each other, so will their revolutions be performed in similar proportions of 
 time, and the velocity of the lathe-mandrel will be increased in the inverse ratio, as the length of the 
 lines a b, ef, g h, and ij ; consequently, the right-angled triangle a b c will represent the time that would 
 be required to turn a surface, when the velocity of the lathe-mandrel is increased in the manner already 
 described. The parallelogram abed will represent the time that would be required, if the velocity re- 
 main unaltered — that is, from the moment the tool is applied to the surface at its greatest diameter, to 
 its arrival at the centre ; for if the length of the line a b represent the time of one revolution at its 
 greatest diameter, the line cd will similarly represent the time of one revolution when the tool reaches 
 the centre ; therefore, as the length of the iine c d is equal to a b, so will all the intermediate revolutions 
 be performed in similar spaces of time. 
 
 This inquiry may be usefully applied to determine the period of time necessary for surface-turning. 
 Thus, if we wish to know what time would be required to turn a plane surface of cast-iron, the diame- 
 ter being twenty-four inches, to make fifty revolutions or cuts in each inch of the radius, and to pass the 
 tool at the rate of 15 feet per minute: Multiply the circumference, say 75‘39 inches by the radius 
 equal 12 inches, then multiply the product, 904'68, by the number of revolutions or cuts in one inch of 
 the radius, in this instance 50, this will give 45,234 inches ; divide this by 12, to reduce it to feet, and 
 we have 3769'5 ; divide again by 15, which gives 251'3 minutes, and lastly dividing by 60, we have 4 
 hours, ll - 3 minutes; consequently this would be the time, if each revolution were performed in equal 
 
TOOLS. 
 
 741 
 
 portions of time, but if the speed of the lathe-mandrel be regulated so that the surface to be turned 
 shall always pass the tool at the same velocity, then the time required to perform the work will be 
 only one-half of the above ; for in this case we must multiply the radius by one-half of the circumfer- 
 ence, as that will be a mean proportion of the lengths of all the intermediate revolutions. 
 
 We have now arrived at a very important and interesting inquiry: — namely, the principle and mode 
 of action of automatic or self-acting tool-machines. 
 
 If we consider the separate and distinct parts which combined make up a machine, whether simple 
 or complex, to be disunited and viewed in detail, we shall find that their constituent parts, however nu- 
 merous, are composed either entirely or partially of certain original geometrical figures, so that it is evi- 
 dent the more nearly the configuration of each individual part approaches strict mathematical truth, 
 the more regular and perfect will be the performance of the machine. 
 
 But the accuracy and precision of workmanship here predicated, and which peculiarly distinguishes 
 the machinery of the present day, is obviously unattainable by mere manual dexterity ; it is principally 
 to be attributed to the slide-rest. 
 
 The invention and introduction of this tool may justly be considered an era in the history of construc- 
 tive mechanism ; it has entirely superseded both manual labor and dexterity, which previously were re- 
 quired ; added to which, it enables us to produce work infinitely superior, and in a much shorter space 
 of time than could be effected by hand-turning : so many and so conclusive are the beneficial results con- 
 sequent to the introduction of this tool that it is not affirming too much to assert that nearly all the im- 
 provements in modern machinery are in a greater or less degree to be attributed to its almost universal 
 application in some or other of its many and varied forms. 
 
 It constitutes no part of the present inquiry to investigate the principles of turning, except so far as 
 is absolutely necessary to illustrate the subject in hand. Let us suppose then, that instead of the tool 
 being held and guided by the hand of the workman, assisted merely by muscular strength, the same 
 tool is firmly fastened to the lathe-rest, so that during the operation of cutting, it could be slid along the 
 bed of the lathe, in a direction parallel to the axis of the work, the result of this operation would ne- 
 cessarily be a cylinder ; if, however, the tool move in a line forming an angle with the axis of the man- 
 drel, a conical form would be obtained, and if it operate at right angles to the same axis a plane surface 
 would be the result. Such are the elementary principles on which this important, and in many respects 
 invaluable tool is constructed, the details of which, and the different forms, we defer for the present, 
 thinking it preferable in the first instance to describe the machine of which it forms an appendage. 
 
 One of the primary and most indispensable requisites of a well-constructed lathe is, that the centre of 
 the cone-spindle should coincide exactly with the adjustable centre of the movable head-stock, or, in 
 other words, that each of these parts should be in the same line, parallel to the face of the lathe-bed. 
 
 The spindle is a very important part of the lathe, as upon its truth and accuracy of motion the circu- 
 lar rotation of any work attached to it mainly depends ; it is usually made of iron, but the working 
 parts of the two extremities are altogether of steel, which are hardened after being turned and finished ; 
 they are then ground in their places to fit the collars or bearings with finely pulverized Turkey stone 
 and oil; the left-hand end lias a hole bored exactly in its centre to receive the point of a screw, which 
 supports and retains it in its place, as shown in Figs. 2523 and 2524, p. 176. 
 
 The other, or right-hand end. of the spindle, is somewhat larger, and has a conical hole bored in the 
 direction of its axis for the purpose of receiving a centre point ; this is disengaged when necessary by 
 means bf any tapered instrument which, being inserted in a slot cut in the mandrel, acts as a lever and 
 forces the centre forwards. 
 
 In the larger class of lathes the spindle is usually fitted up to run in divided collars of brass or gun- 
 metal ; these slide on V-shaped grooves cast in the head-stock, and are adjusted to fit the neck of the 
 mandrel or spindle by means of screw-bolts which pass through a cap or plate of wrought-iron, fitted on 
 the upper surface or top of the head-stock. 
 
 V arious contrivances have from time to time been suggested to avoid the inconvenience of a back- 
 screw, and at the same time insure uniformity of position under all possible circumstances. The boring and 
 turning machine, pp. 180, 181, and 182, offers an example of this modification : here the sjoindle works 
 in divided collars, but has shoulders at the necks, by which contrivance all longitudinal motion is en- 
 tirely avoided. The method adopted by Mr. Whitworth, of Manchester, to effect this object is extremely 
 ingenious, and peculiarly entitled to the distinctive epithet, self-sustaining ; as a specimen of the adap- 
 tation of mechanical means applied to produce certain results, it is probably unrivalled. 
 
 In this lathe the inner journal of the spindle is turned conically, but at two different angles, that part 
 next the nose being more acute than the remaining portion. This arrangement meets the great difficulty 
 attendant on conical bearings, as the base of the cone is opposed to direct pressure, and consequently 
 removes all danger of the spindle becoming fixed or jammed in its collar. The sliding cone which is 
 placed upon the spindle for working in the outer bearing, becomes, as it were, a part of the spindle, but 
 having longitudinal motion ; it tends to balance the effect of pressure applied directly to the screw. 
 
 The method shown in the sectional view, Fig. 2532, p. 177, is by no means so well contrived as in this 
 case ; a set-screw is introduced to counteract longitudinal motion by direct pressure against the left- 
 hand end of the spindle. 
 
 The movable or right-hand head-stock now requires consideration. The first decided step towards 
 improvement in this part of the lathe may doubtless be traced to the substitution of a plain cylinder for 
 a screw, both terminating alike in a conical point; in the former case the cylinder turning upon itself, 
 the apex of the cone is not so liable to deviation, but this does not compensate for the absence of regu- 
 lar pressure, which can be imparted at will, and at any moment, by means of a screw, and that in a 
 degree exactly required by the nature of the case ; nevertheless this great inconvenience must not be 
 overlooked, the screw is extremely liable to vary relatively to the centre line. If, for instance, either 
 the pin or the thread be slightly twisted, which it frequently and unavoidably is, the point will describe 
 a small circle at each revolution, and however well and carefully the thread of the screw may be cut 
 
742 
 
 TOOLS. 
 
 it is almost impossible to make it perfectly regular and mathematically true ; consequently, if the centraj 
 line of the cone, -which forms the point, be not that of the screw itself, the same effect will be produced 
 These and other considerations of a like nature that might be adduced, probably suggested the ar 
 rangement shown in Fig. 2538, which combines the simplicity and uniformity of position of the cylinder 
 with the mechanical power of the screw. In this case the sliding cylinder in the head-stock is deprived 
 of rotary motion, its outer end being connected by a coupling to a second cylinder of smaller diameter, 
 which constrains both to move in a parallel direction ; between these, a square-threaded screw works, 
 which is capable only of longitudinal motion, being connected to the aforesaid coupling, so that the 
 screw being worked to the left hand, compels the cylinder in the head-stock to travel with it, as is evi 
 dent from inspection of the figure. 
 
 The form of head-stock just described probably suggested that generally known as the cylinder head 
 stock. This was invented simultaneously, we believe, by M. Collas, of Paris, and Mr. Joseph Clement, 
 of London. The arrangement now usually adopted is shown in section in Fig. 3458. The head-stock 
 is bored out true and an iron or steel cylinder ground therein so as to insure an accurate fit ; this re- 
 ceives a forward and backward motion from a screw which is rendered endless by means of a collar or 
 
 3458. 3459. 
 
 cap, and is worked by a handle-wheel. The sliding cylinder is fixed when requisite by a pinchmg- 
 screw, which presses against a piece of iron let into the head-stock. A sectional view of another mode 
 of fitting up is given in Fig. 3459. This is unquestionably not so expensive to get up as that just de- 
 scribed, but it is liable to the objection, that nearly the whole amount of pressure is thrown upon the 
 driving-screw connected with the cylinder and attached to the handle-wheel. In this latter example 
 the mode of fixing the spindle in its required position is superior to that shown in Fig. 3458. A malle- 
 able iron ring, bored out so as accurately to fit the spindle, is let into a recess in the head-stock, and 
 tightened up by means of a handle passing through a screwed shank projecting from the ring. 
 
 In some cases it is desirable to possess the means of moving the shifting head-stock in a direction at 
 right angles to the bed of the lathe. A very convenient mode of effecting this is shown in Figs. 2523 
 and 2524, by means of the screw f, which causes the head-stock to move transversely, an arrangement 
 which is peculiarly applicable to conical turning. 
 
 In heavy lathes the sliding head-stock is usually moved along the bed by means of a train of bevel- 
 wheels, as in Fig. 2542. Here a bevel-pinion attached to a horizontal spindle, which is worked when 
 necessary by a crank-handle fitted upon the square end o, gives motion to a bevel-wheel upon one end 
 of a vertical shaft, which has its bearings inside a hollow column cast in the body of the head-stock for 
 that purpose. On the other end of this shaft is a bevel-pinion ; this again geers with a small bevel- 
 wheel keyed upon the spindle p, 'which works in bearings attached to the sole of the head-stock and 
 also carries a pinion which works into the rack M, fixed upon the bed-plate of the lathe, and thus obvi- 
 ously completes the connection, enabling the workman to adjust the sliding head-stock in any required 
 position with ease and facility. 
 
 Cones or speed-pulleys are very important adjuncts to tool-machines in general, and more especially 
 the lathe, as from the nature of the operations performed by it, it is a primary requisite that the range 
 of variation in the velocity of the spindle should be as large as possible. Professor Willis has investi- 
 gated the mechanical principles of their adjustment in a very clear and satisfactory manner. 
 
 Supposing a pair of cones or speed-pulleys to be arranged upon two parallel axes and in opposite 
 directions, we have an easy mode of changing the ratio of the angular velocity of the shafts by simply 
 moving the belt from one pair of speeds to another. 
 
 In this case it is evident that the diameters of each pair of opposite pulleys should be so adjusted that 
 the belt shall be equally tense upon any pair of the whole series ; this, as may be- easily demonstrated, 
 is attained by making the sum of each pair of opposite pulleys equal throughout the whole series. 
 
 We have now to describe the slide-rest, a tool which has unquestionably contributed more than any 
 other to the improvement of modern machinery. The invention of this truly important tool is claimed 
 by Mr. Nasmyth for the late Mr. Henry Maudslay ; but, as it appears to us, the conclusion arrived at 
 by that gentleman has been hastily adopted and without sufficient inquiry, inasmuch as a form certainly 
 similar in all important details was well known and commonly used by rose-engine turners long pre- 
 viously, added to which we may remark that the original slide-rest constructed by Mr. Maudslay for 
 Mr. Bramah bears so slight a resemblance to that now in use as scarcely to be capable of identification ; 
 moreover, it is extremely doubtful whether a form of rest, known as the parallel rest, as well as a tool 
 very similar in principle, invented by the late Earl Stanhope for turning metallic surfaces of large di- 
 mensions truly plane, did not precede the slide-rest of Mr. Maudslay. 
 
 It is foreign to our purpose to pursue the subject further, nor are we disposed to depreciate the great 
 merit of an ingenious and highly talented engineer ; nevertheless, as the principle has been so extensively 
 and so successfully applied to modern tool machinery, we have been solicitous to perform an act of jus- 
 tice in attributing to those who have in any way contributed to the invention of this important tool a 
 fair share of commendation. 
 
 The form of slide-rest shown in Figs. 2542 and 2543 is a very convenient arrangement in many of its 
 
TOOLS. 
 
 74 o 
 
 details, and the one most commonly adopted. Here J is the saddle-plate upon which the slide-rest K 
 is supported, and the longitudinal slide L which carries the tool-holder is firmly secured upon the part 
 K by the screw u ; the parallel motion of the tool-holder is obtained by means of the screw r, and simi- 
 larly a transverse motion of the same in order to place the tool in and out of cut by the screw s ; these 
 necessarily work at tight angles to each other, and the tool itself is made fast on the tool-holder by the 
 two clamps u. The adjustment requisite for setting the tool to the work is effected by disengaging the 
 sole K from the saddle-plate J ; the nuts on the bolts which pass through the slots, shown in the plan 
 view, Fig. 2543, being released, by this means the sole K may then be moved to the requisite distance 
 from the longitudinal axis of the lathe, and to a certain extent in the line of that axis by shifting the 
 bolts in the dovetail grooves of the saddle-plate, should that operation be more convenient than to shift 
 the latter on the bed-frame of the lathe. 
 
 A transverse adjustment to a limited extent may be obtained by means of the screw s, and the tool- 
 carrier may be adjusted longitudinally by the screw r. 
 
 The slide-rest we have now to describe is due to the ingenuity of Mr. Joseph Whitworth. It is un- 
 questionably an excellent specimen of constructive mechanism, combining the requisite stability with 
 great accuracy of motion, and the manner in which the details are worked out displays considerable 
 ability and mechanical talent. Figs. 3460 and 3461, the latter being a section, show the rest set for 
 facing a circular plate ; that is, the motion of the upper slide is in a line at right angles to the lathe-bed 
 A A, which is bolted in the usual manner to the supports B B. 
 
 The saddle upon which is placed the carriage of the rest is simply a broad and strong plate of cast- 
 iron C C, planed true and finished by scraping upon both horizontal faces. The slides a a, similarly 
 planed and dressed, are screwed to the lower surface of the saddle on either side of the lathe-bed, to 
 enable it to traverse with uniform motion its entire length without shake or play, and so arranged as to 
 compensate for wear and tear by means of lateral screws countersunk in the cheeks of C 0. 
 
 When the saddle is required to remain stationary during the work, as, for example, when a circular 
 or other plate is to be faced, it is firmly fixed on the lathe-bed A A by means of a single screw-bolt b, 
 the nut of which is screwed up by the lever-handle c. 
 
 The carriage of the rest is composed of three principal parts : the first D D, which rests upon the sad- 
 dle, and is susceptible of different positions ; the second E is a plate movable upon the preceding, and 
 the third F which carries the tool. The base or carriage is of cast-iron, planed and finished by scraping 
 not only on the two horizontal faces, but also on the two upper lateral edges, which are angular like 
 those of the lathe-bed, so as to receive the slides e e fitted on each side of the rectangular plate E. A 
 screw-bolt d, the square head of which is lodged in a gap sunk in the saddle C C, serves to adjust the 
 carriage D D upon the saddle-plate, and this adjustment obviously depends upon the diameter of the 
 piece to be turned. 
 
 The rectangular plalfe E is rendered movable in the direction of the lengtl# of the carriage D D by 
 means of an endless-screwy, which is entirely sunk in its thickness, and receives a rotary motion either 
 from the handle g or from the lathe itself. This endless-screw works in a brass nut fitted under the 
 plate E, and being deprived of endlong motion, it necessarily follows that in its rotation it imparts a 
 forward aud backward motion to the nut, and consequently the tool-carrier. 
 
 The part F, which may properly be designated the tool-carrier, is susceptible of another movement — 
 that is, in a direction exactly at right angles to that just described— by means of a second endless-screw 
 smaller than the former ; this is intended to be worked only by the handle h, and that in the event of 
 its being necessary to regulate in an exact manner the position of the tool with regard to the piece upon 
 which it is to operate. This endless-screw works in a brass nut attached to the plate E, and conse- 
 quently imparts a forward and backward motion to the tool-carrier F, which moves between two slides 
 screwed upon this plate. 
 
 The tool i, which is intended to act upon the material either for turning or screw-cutting, is securely 
 fixed on the tool-carrier F by vertical pinching-screws jj, which are screwed through the thickness of 
 the upper plate or cap ; these screws, four in number, are placed 
 at the anglea of the cap, an arrangement which allows the tool 
 to be fixed in different directions, and in such a manner that it 
 is always acted upon by two screws. This disposition enables 
 the workman to employ two tools which shall act at the same 
 time or nearly so upon the material ; for instance, the one to 
 rough out and the other to complete the work. 
 
 Motion is communicated to the carriage, and consequently to 
 the tool-slide, by a peculiar arrangement of the guide-screw, 
 which is so formed as to be alike capable of performing the office 
 of a rack as well as that of a screw > to this end the thread is 
 rounded off both at top and bottom, instead of being either tri- 
 angular or. square. It is thus enabled to work either in a nut or 
 with a tangent-wheel. 
 
 This guide-screw is shown at G-, Fig. 3460. It is placed with- 
 in the lathe-frame, not in the direction of the axis of the machine, 
 but rather on one side, in order to screen it from the falling turn- 
 ings, and the nut k, when needful, is taken out of geer by the 
 pin l. When the guide-screw is required to answer the pur- 
 pose of a rack — as, for instance, to bring the saddle, and consequently the carriage, to any particular 
 position — the nut k is disengaged, and the handle in, the socket of which is fitted on a horizontal spindle 
 carrying the small meter-wheel n, which geers with a larger one o, keyed on one end of a vertical shaft 
 placed in the centre of the saddle 0, and on the other extremity of this shaft is a tangent-wheel p 
 which works with the guide-screw of the lathe. JN T ow as this last is deprived of rotary motion, it is evj 
 
 3460. 
 
744 
 
 TOOLS. 
 
 dent that by turning the handle in, the tangent- wheel p, driven as already described, will produce pre 
 ciselv the effect of a rack ; that is to say, the saddle and carriage will receive a traversing motion ic 
 the direction of the length of the lathe-bed. 
 
 In actual work the saddle, and consequently the rest itself, is placed in any required position, the 
 handle in being removed and the nut k brought into connection with the guide-screw G, which, actuated 
 and regulated by a train of wheels attached to the lathe, causes the saddle with its appurtenances t» 
 travel with any degree of speed that may be required. 
 
 By a peculiar and ingenious arrangement, the guide-screw is made to drive the carriage and tool- 
 carrier in a direction at right angles to the axis of the lathe. This is effected in the following man- 
 ner : — with the mitre-wheel o a similar but smaller one q geers ; this is keyed on the end of a shaft iu 
 the same straight line as that which carries the small mitre-wheel n. At the opposite extremity of this 
 axis is a spur-wheel r which geers with a similar spur-wheel s mounted on an iron spindle, which ter- 
 minates at the other end- in a grooved shoulder ; this axis is movable in a socket which forms a support 
 and is fixed to the saddle C, and by means of an 'ingenious contrivance the forked lever t is made to 
 connect or disconnect at pleasure the spindle that carries the spur-wheel s, with the square end of the 
 screw f of the carriage 1) 1). 
 
 It is obvious, if we suppose the saddle to be fixed on the lathe-bed — and to effect this it is merely 
 necessary to screw up the bolt c — that the guide-screw G giving motion to the tangent-wheel p deter- 
 mines the motion of the toothed-wlieels, and consequently that of the screw/, which after this manner 
 gives motion to the carriage and the tool-carrier, to which we have given, by anticipation, the position 
 shown in the sectional view, Fig. 8461. It is evident that when this transverse motion is not required, 
 it is only necessary to throw the wheels out of geer by means of the forked lever t, and then these 
 wheels will revolve on their axes without producing any effect. 
 
 \ 
 
 The collars or bearings in which the axes of the bevel-wheels n and q revolve freely, are nothing 
 more than long hollow cylinders bored out true, and fixed on the saddle or bed-plate c, and to avoid 
 the injury which might result from these wheels becoming clogged by chips of metal, they are usually 
 protected by a metallic cover either of tin or sheet-brass. 
 
 In the construction of steam-engines and engineering work generally, there are a great number of 
 parts, such as steps, bushes, ifcc., which require their outer diameter to be turned truly concentric with 
 the hole bored through them. The most general method of accomplishing this, is by driving the work 
 upon a mandrel sufficiently tight to withstand the action of the turning-tool. The common mandrel, 
 which is perhaps the most universal adjunct of the lathe, is a cylindrical bar of steel, turned with an 
 exceedingly slight taper to fit the central hole of the work. 
 
 The time lost in preparing these mandrels, and the great weight of useless metal which must thus 
 be kept in stock, prove serious objections to their use, and led Mr. Hick to the invention of the expand- 
 ing mandrel, by which various sizes of holes may be fitted. 
 
 Figs. 3462 and 8463 represent a longitudinal section and an elevation of the mandrel, the expanding 
 wedges being shown in two different positions, a is the mandrel, *the central portion of which is turned 
 conically as at b. This cone is provided with four dovetail grooves c running in the direction of the 
 axis of the mandrel, and fitted to receive the four wedges dd, shown in Fig. 3462, in their highest po- 
 sition. The dotted circles in the end view represent the work, which is placed upon the four wedges ; 
 these are pressed onwards by the hollow conical collet e, urged by the nut f working' on the screw- 
 threads cut on the mandrel. In this manner the wedges d are driven up the inclined grooves, and thus 
 fix the mandrel concentrically within the hole of the work so that any diameter of hole may be readily 
 fitted, which is within the range of the travel of the wedges. 
 
 Another equally important appendage of the lathe, is the universal chuck. Yarious views of this 
 chuck are given in Figs. 2542 — 2545, pp. 180-2. For turning or boring articles of a regular external 
 configuration, this arrangement has a decided advantage over the common chuck, where each adjust- 
 ing screw is moved separately ; and effects a considerable saving in time, in setting the work. 
 
 There are, besides the modification just referred to, various other species of chucks, among which we 
 may class Mr. Bodmer’s as one of the best. 
 
TOOLS. 
 
 715 
 
 In this arrangement, the clutches are expanded and contracted by means of a series of radiating 
 screws, each of which carries a pinion geering with a large central wheel on the front plate of the 
 chuck ; the work is fastened by setting the lathe in motion, and holding back the front plate until the 
 wheel upon it shall have driven in the clutches worked by the screws sufficiently far to grasp it. 
 
 The object of change-wheels applied to a lathe is, generally speaking, to. obtain a screw of any re- 
 quired pitch ; that is, in relation to the leading or guide screw* by which the cutter is moved in a lon- 
 gitudinal direction. 
 
 If a spur-wheel be attached to the left-hand end of the lathe-spindle, and.so arranged as to geer with 
 mother spur-wheel similarly fixed on the axis of the guide-screw, and continuous motion be commu- 
 nicated to the lathe-spindle, it is evident that this motion will be transferred by means of the aforesaid 
 wheels to the saddle of the slide-rest ; consequently a screw-tool attached thereto, will receive direct 
 rectilinear motion, and thus trace the spiral thread of a screw on the exterior surface of any revolving 
 cylinder opposed to its action. 
 
 The relative proportions of these wheels obviously determine the pitch of the screw to be cut, as 
 compared with that of the guide-screw of the lathe ; so that if they are of equal diameter, or, what is 
 the same thing, have an equal number of teeth, the result will be a screw of the same pitch as that of 
 the leading screw ; but if the driving-wheels be larger than the driven — suppose in the proportion of 
 two to one, then will the pitch of the work be exactly double that of the guide-screw, and if these pro- 
 portions were reversed a contrary result would follow. 
 
 It is obvious in such a case as we have here supposed, that, as the wheel fixed on the lathe-spindle 
 and that upon the guide-screw, each revolve in contrary directions, all screws cut by this arrangement 
 will be the reverse of the guide-sCrew, or left-hand threaded. In order, therefore, to cut a right-hand 
 screw, ^t will be necessary to introduce an intermediate wheel geering with both wheels, so that the 
 direction of motion of the work shall be the same as that of the lathe-spindle. 
 
 The principle of this arrangement is shown in Fig. 3464, entirely _ 
 
 disconnected from the frame-work of the lathe, and without strict 
 regard to proportion, it being intended merely to exhibit the parts 
 as distinctly as possible. Here A A' is a portion of the lathe- 
 spindle, to which is attached in the usual way a cylindrical rod, 
 for the purpose of cutting a thread upon it. G represents the 
 leading or guide screw revolving in suitable bearings, and giving 
 motion by means of a nut to the saddle, and consequently the 
 carriage of the rest, upon which is firmly clamped a suitable tool 
 intended to cut the screw. 
 
 In this arrangement it is manifest that every revolution of the 
 guide-screw G will cause the rest to advance through a space ex- 
 actly equal to its own pitch, or, in other words, supposing the 
 guide-screw to have four threads in the inch, it will, in every rev- 
 olution it makes, advance the rest, and consequently the tool or 
 cutter, one-fourth of an inch end-long upon the work, so that if the 
 lathe-spindle revolve with the same velocity as the guide-screw, 
 the tool will produce a screw of precisely similar pitch ; but if, on 
 the contrary, AA' revolve with less velocity than G, then the 
 effect will be a greater pitch, and vice versa. How if the lathe- 
 spindle and the guide-screw be connected by a set of change- 
 wheels, we have the means, by properly choosing the numbers of 
 these wheels, to obtain any desired pitch. This is practically 
 etfected by an intermediate axis which is supported by a grooved 
 bearer ; this carries an arrangement of additional change-wheels, 
 according to circumstances and the conditions of the case. The 
 leading or guide screw which communicates motion to the saddle of the slide-rest is driven by a train 
 
 * Screw-cutting and boring machines are reducible to the principle of aggregate motion. For the cutting of a screw ir 
 In fact the tracing of a spiral upon the surface of a cylinder, and the motion of boring is also the tracing of a spiral unor 
 
746 
 
 TOOLS. 
 
 of wheels which are in connection with the spindle of the lathe, it passes through and forms the axis of 
 a movable piece H, and at its extremity carries the fast-wheel 1, which geers with a pinion E ; this 
 and the wheel F, wnich geers with the pinion D upon the end of the lathe-spindle, are carried by r 
 stud B fixed in a straight slot cut in the movable arm H, which' has likewise a curvilinear slot near its 
 end, through which two fixed studs pass , upon these studs pinching-nuts are placed, which being 
 screwed up tightly, retain it securely, and by altering the angular position of H, a pinion of greater or 
 less diameter than I) may be used, and consequently the motion of the leading or guide screw regu- 
 lated. 
 
 Having now explained the arrangement of geering necessary for effecting a change of speed in the 
 guide-screw, we shall, for the sake of a practical illustration, give determinate values to the wheels 
 D F E and J. Thus let the number of teeth in the wheels D and E be 30, and that in F and J 60 each, 
 the pitch of the guide-screw G being -J inch, or in other words, that it lias two threads per inch. It is 
 
 now evident that one complete revolution of G will advance the tool through the space -gy-', and simi- 
 
 30 X 30 
 
 larly one revolution of A will advance the tool through the space = 0'25 turns of G, or ith 
 
 6 ^ 60 X 60 ’ 8 
 
 inch, and consequently the pitch of the screw cut by this arrangement will be Jth inch. In this man- 
 ner any desired pitch of screw may be cut by proportioning the change-wheels accordingly. This may 
 be much facilitated, by arranging the various pitches of screw’s in a tabular form and placing the re- 
 spective change-wheels required for each opposite to them, so that all computation during the actual 
 progress of the work is avoided. 
 
 In order, however, to meet emergencies, it is necessary that the process of calculation for any given 
 pitch should be thoroughly understood, and for this purpose we shall give an example as a guide. 
 Suppose it is required to cut a screw which shall contain 13 threads in the inch. Here the ratio of 
 
 t 23 ) 
 
 speed between the cone-spindle and the guide-screw is required to be as 6 J to 1 ^ — \ , so that 
 
 — t &c. = 64. In this case, the wheels D and J are supposed to be geered together merely 
 
 (D) 20. 24 1 1 & o j 
 
 by a single carrier-wheel ; but as this arrangement is not always convenient, we shall now find the ratios 
 of the wheels as given in Fig. 3464, where four are used. Here we must remember that the condition 
 of the case is that the numerator divided by the denominator of the expression (13) shall be 64- We 
 
 will assume 28 and 56 as the respective values of D and J, or — = 2. Hence we have only to find 
 
 we have 
 
 E 64 
 
 such values of F and E, so that — = -^ or 34, which informs 
 
 D 
 
 us that E must have 34 times as many 
 
 teeth as F. Suppose then F has 32 teeth, we have 32 X 34 = 104 = the number of teeth in E, the 
 whole set of wheels standing as follows : D = 281, J = 56, F = 32, E = 104. This result is capable 
 
 of verification as follows: — — 2 = 2. 31. 2 ' 13, or the number of threads per inch of the screw to 
 28. 32 1 
 
 be cut. Thus in all cases of calculations of this nature, the expression in general terms stands thus : 
 
 (Ho. of teeth in J,) (Ho. of teeth in E Ho. of threads per inch of screw to be cut, 
 
 (Ho. of teeth in D,) (Ho. of teeth in F * Ho. of threads of guide-screw. 
 
 The following table shows the train of wheels to be used in cutting screws varying in pitch from 1 
 
 to 70 threads in the inch ; the leading or guide screw is supposed to have two threads per inch, yet 
 
 may the table be still employed where the leading screw has four threads to the inch, for the same 
 train of wheels would suit for cutting screws of double fineness ; and similarly when the leading screw 
 has only one thread to the inch, a screw of only one-half the fineness will be produced with any train 
 given in the table. 
 
 In the first columns it will be observed that the wheel and pinion carried by the stud B are omitted ; 
 these not being required in cutting screws of the pitches there stated, are displaced, and a simple car- 
 rier-wheel substituted for them. To facilitate this arrangement, the wheel J, on the leading screw, has 
 the boss of its socket longer on one side than the other ; so that when reversed, as in this instance, it is 
 brought into train with the carrier-wheel, placed upon the stud ; and this again is placed in train w T ith 
 the pinion D. 
 
 Such are the general principles of screw-cutting for single threads ; but when it is required to cut a 
 multi-threaded screw, it is evident that some additional apparatus will be requisite to effect the requi- 
 site exactitude of division, so as to bring in each parallel thread in its proper place. 
 
 the surface of a hollow cylinder; the tool being in both cases the describing point, and the plain cylinder the surface. 
 Now as the tracing of this spiral is resolvable into two simultaneous motions, one of revolution with respect to the axis 
 of the cylinder, and the other of transition parallel to that axis, we have in the construction of machines for boring and 
 screw-cutting the choice of four arrangements: 
 
 (i.) The cylinder may be fixed and the tool revolve and travel. This is the case in all simple instruments for boring 
 and tapping screws, in machines for boring the cylinders of steam-engines, and in engineers’ boring machines. 
 
 (2.) The tool may he fixed and the cylinder revolve and travel. Screws are cut upon this principle in small lathes with 
 a traversing mandrel. ' 
 
 (3.) The tool may revolve and the cylinder travel. The boring of the cylinders of pumps is often effected upon this 
 principle. 
 
 (4.) The cylinder may revolve and the tool travel. Guns are thus bored, and engineers’ screws cut in the lathe. 
 
TOOLS. 
 
 747 
 
 CD O 
 
 a o 
 
 6 -2 
 £ u 
 P. 
 
 No. of 
 teeth on 
 
 No. of threads 
 per inch of screw. 
 
 No of teeth on 
 
 No. of threads 
 per inch of screw. 
 
 No. of teeth on 
 
 No. of threads 
 per inch of screw. 
 
 No. of teeth on 
 
 Mandrel pin- 
 ion D. 
 
 Leading 
 screw-wheel I. 
 
 Mandrel pin- 
 ion D. 
 
 Stud-wheel F. 
 
 Stud-pinion 
 
 K. 
 
 Leading 
 screw-wheel I. 
 
 Mandrel pin- 
 ion D. 
 
 Stud-wheel F. 
 
 Stud-pinion 
 
 E. 
 
 tp s 
 
 O ^ 
 
 o 
 
 Mandrel pin- 
 ion D. 
 
 fa 
 
 3q 
 
 3 
 
 ‘rH 
 
 m 
 
 tD 03 
 
 o P 
 
 CJ 
 
 1 
 
 80 
 
 40 
 
 84 
 
 40 
 
 55 
 
 20 
 
 60 
 
 18 
 
 40 
 
 60 
 
 20 
 
 120 
 
 32 
 
 30 
 
 80 
 
 20 
 
 120 
 
 14 
 
 80 
 
 50 
 
 84 
 
 90 
 
 85 
 
 20 
 
 90 
 
 184 
 
 80 
 
 100 
 
 20 
 
 150 
 
 33 
 
 40 
 
 110 
 
 20 
 
 120 
 
 u 
 
 80 
 
 60 
 
 84 
 
 60 
 
 70 
 
 20 
 
 75 
 
 19 
 
 50 
 
 95 
 
 20 
 
 100 
 
 34 
 
 30 
 
 85 
 
 20 
 
 120 
 
 14 
 
 80 
 
 10 
 
 94 
 
 90 
 
 90 
 
 20 
 
 95 
 
 194 
 
 80 
 
 120 
 
 20 
 
 130 
 
 35 
 
 60 
 
 140 
 
 20 
 
 150 
 
 2 
 
 90 
 
 90 
 
 94 
 
 40 
 
 60 
 
 20 
 
 65 
 
 20 
 
 60 
 
 100 
 
 20 
 
 120 
 
 36 
 
 30 
 
 90 
 
 20 
 
 120 
 
 24 
 
 80 
 
 90 
 
 10 
 
 60 
 
 75 
 
 20 
 
 80 
 
 204 
 
 40 
 
 90 
 
 20 
 
 90 
 
 38 
 
 30 
 
 95 
 
 20 
 
 120 
 
 24 
 
 80 
 
 100 
 
 104 
 
 50 
 
 70 
 
 20 
 
 75 
 
 21 
 
 80 
 
 120 
 
 20 
 
 140 
 
 39 
 
 40 
 
 120 
 
 20 
 
 130 
 
 24 
 
 80 
 
 110 
 
 11 
 
 60 
 
 55 
 
 20 
 
 120 
 
 22 
 
 60 
 
 110 
 
 20 
 
 120 
 
 40 
 
 30 
 
 100 
 
 20 
 
 120 
 
 3 
 
 80 
 
 120 
 
 12 
 
 90 
 
 90 
 
 20 
 
 120 
 
 224 
 
 80 
 
 120 
 
 20 
 
 150 
 
 42 
 
 50 
 
 140 
 
 20 
 
 150 
 
 sj 
 
 80 
 
 130 
 
 I2f 
 
 60 
 
 85 
 
 20 
 
 90 
 
 22J 
 
 80 
 
 130 
 
 20 
 
 140 
 
 44 
 
 30 
 
 110 
 
 20 
 
 120 
 
 34 
 
 80 
 
 140 
 
 13 
 
 90 
 
 90 
 
 20 
 
 130 
 
 23| 
 
 40 
 
 95 
 
 20 
 
 100 
 
 45 
 
 30 
 
 90 
 
 20 
 
 150 
 
 34 
 
 80 
 
 150 
 
 134 
 
 60 
 
 90 
 
 20 
 
 90 
 
 24 
 
 65 
 
 120 
 
 20 
 
 130 
 
 454 
 
 40 
 
 130 
 
 20 
 
 140 
 
 4 
 
 40 
 
 80 
 
 134 
 
 80 
 
 100 
 
 20 
 
 110 
 
 25 
 
 60 
 
 100 
 
 20 
 
 150 
 
 50 
 
 30 
 
 100 
 
 20 
 
 150 
 
 44 
 
 40 
 
 85 
 
 14 
 
 90 
 
 90 
 
 20 
 
 140 
 
 254 
 
 30 
 
 85 
 
 20 
 
 90 
 
 52 
 
 35 
 
 130 
 
 20 
 
 140 
 
 44 
 
 40 
 
 90 
 
 144 
 
 60 
 
 90 
 
 20 
 
 95 
 
 26 
 
 70 
 
 130 
 
 20 
 
 140 
 
 524 
 
 40 
 
 140 
 
 20 
 
 150 
 
 44 
 
 40 
 
 95 
 
 15 
 
 90 
 
 90 
 
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 27 
 
 40 
 
 90 
 
 20 
 
 120 
 
 55 
 
 30 
 
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 20 
 
 150 
 
 5 
 
 40 
 
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 16 
 
 60 
 
 80 
 
 20 
 
 120 
 
 274 
 
 40 
 
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 110 
 
 56 
 
 30 
 
 120 
 
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 140 
 
 5-J- 
 
 40 
 
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 164 
 
 80 
 
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 28 
 
 75 
 
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 30 
 
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 6 
 
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 164 
 
 80 
 
 110 
 
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 284 
 
 30 
 
 90 
 
 20 
 
 95 
 
 65 
 
 30 
 
 130 
 
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 64 
 
 40 
 
 130 
 
 17 
 
 45 
 
 85 
 
 20 
 
 90 
 
 30 
 
 70 
 
 140 
 
 20 
 
 150 
 
 70 
 
 30 
 
 140 
 
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 7 
 
 40 
 
 140 
 
 Hi 
 
 80 
 
 100 
 
 20 
 
 140 
 
 
 
 
 
 
 
 
 
 
 
 14 
 
 40' 
 
 150 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 8 
 
 30 
 
 120 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Two separate contrivances have been devised for this purpose. Pihet’s apparatus is shown in Figs, 
 8465 and 8466 ; the former of which is a front elevation and the latter a section in a line with the axis 
 of the lathe, a is a cast-iron disk cut with a female screw to tit the nose of the lathe-spindle, and on 
 the face of this disk is fitted the division-plate b, the tubular portion of which also answers for chucking 
 the work. The circumference of this disk is divided by notches, into 60 equal parts, numbered respect- 
 ively from 0 to 60, into which the spring-catch or stop c takes, so that when the disk a is put in mo- 
 tion, and^the catch put down in any notch as required, the whole moves together as in one piece. 
 
 The disk b is held in its place merely by friction generated by the pressure of the ring e ; this ring 
 is shown removed in Fig. 8465, in order to show the graduation of the disk e , which is bolted to the 
 disk a, and carries in one portion of its circumference a screw d. This screw passes through the exter- 
 nal ring e, and is screwed into the stop c, so as to fix the latter in any required division of the plate b. 
 
 In cutting a multi-threaded screw by this apparatus, it takes the place of the common chuck, the 
 workman fixing his work to it, by means of the radiating screws in the tubular portion of b. 
 
 Supposing it is required to cut a triple-headed screw, the first operation which is necessary is the 
 detaching of the stop c from the disk, so that the latter may be turned round alone, until the division o 
 comes opposite the hole in the external ring seen at e, in Fig. 3466 ; the screw d is then adjusted so as 
 to connect the division-plate with the disk a, and the first thread of the intended screw is cut through- 
 out its whole length. Now as the thread is to be a triple one, it is obvious that the circumference of 
 the work must be divided into three equal parts, so that each thread may be equidistant when cut; 
 accordingly the stop is again detached, and the division-plate carrying the work turned round, until the 
 notch 20 arrives at the hole e \ the stop is then replaced, and the second thread is cut in a similar man- 
 ner as before. Lastly, the division-plate is moved round, until the notch 40 is seen through the hole e, 
 when the remaining thread is cut, the three having the same reference to each other as the divisions 0, 
 20, and 40 relatively bear to each other. 
 
748 
 
 TOOLS. 
 
 In the production of the minor screws and bolts used in engineering work, the lathe is superseded by 
 the screwing and tapping machine, in which the thread is formed by a travelling die working upon the 
 revolving-bolt intended to be screwed. The principle of the action of this machine will be understood 
 by referring to Fig. 3275, in which we have given an elevation, ground plan, and different detailed 
 views of a single screwing machine of great simplicity. In this arrangement the frame containing the 
 dies travels upon the parallel guide-rods It R, the work being fixed in the chuck L, and entered into 
 the dies which are then contracted until they embrace the bolt sufficiently to be drawn along its surface 
 by its revolution. The quick return motion of the die-frame is produced in the ordinary manner as 
 applied to planing machines. This machine is objectionable on account of its want of compactness 
 otherwise it is a pretty fair specimen of its class. 
 
 The double screwing machine by Messrs. Randolph, Elliot, and Co., of Glasgow, is a much more 
 complete and useful workshop auxiliary than the last, and has, besides, the merit of great compactness. 
 Fig. 3467 is a side elevation of the machine, Fig. 3469 is a ground plan, Fig. 3468 is an elevation of the 
 
 3470. 
 
 nut- tapping end and Fig. 3470 is a similar view of the bolt-screwing end. The frame-work of the ma- 
 chine A A°and the sole-plate B B, are cast in one piece. The driving-cone C is supported by the up- 
 rio-ht frames near the centre of the machine, and carries a pinion D, of 15 teeth, which geers with ha 
 wheel E, of 56 teeth, keyed on the smaller screwing-spindle F ; thus the relative speeds of the driving- 
 tone and the spindle F are as 3-73 to 1. The spindle F again carries a pinion G of 18 teeth, geenng 
 
TOOLS. 
 
 749 
 
 with the wheel H of 72 teeth, keyed on the larger screwing-spindle L the ratio of speed in this 
 case being as 4 to 1. In the end view the chucks KK are shown with square recesses, for the 
 purpose of receiving the heads of taps for tapping-nuts. In the view of the contrary or bolt-screwing 
 end, the chucks L L are provided with plates grooved for the purpose of receiving the screwing-dies, 
 which are adjusted by means of two set-screws, which press against the backs of the dies so as to suit 
 them to any diameter of bolt. The motion of the spindles is stopjred or reversed by the handles M M, 
 at each end of the machine. They are connected by a lever with the vertical rod E, which carries the 
 shifting-strap forks. The top driving-geer consists of three pulleys, a fixed central one, with a loose one 
 on each side, all being on one shaft, which also carries a cone of three speeds exactly similar to C, — 
 the last carries the driving-belts communicating directly with the machine. The centre pulley of the 
 6et of three is much narrower than that on each side of it, so as to allow of the release of the cross- 
 strap before the op^i one comes upon it, and vice versa. For another somewhat similar arrangement, 
 see Figs. 3282 to 3287. 
 
 34G9. 
 
 formed by manual labor, a tedious and uncertain process, but now effected w T ith facility and precision 
 by self-acting machinery. 
 
 In Figs. 2974 to 2976 we have given detailed views of a complete machine for this purpose, by Mr. A, 
 Mylne, of Glasgow. The nut to be cut is fixed on the upright spindle of the support r, and is brought 
 in contact hvith the revolving-cutter x by means of the screw y, the requisite division of the faces of the 
 nut being effected by means of the circular table, which is provided with six equal notches fitted with 
 a spring-catch from the lever n. This machine is also provided with a self-acting feed motion, by which 
 the nut is gradually moved up to the cutter while in action. This is effected by the shaft c of the speed- 
 pulley e, which carries a worm s geering with the wheel h, upon the shaft of which is fixed a pinion 
 geering with a rack on the lower side of the table carrying the nut. This motion may be dispensed 
 with when thought necessary, and the work may be carried forward by hand, by means of the hand- 
 wheel and shaft b. 
 
 This machine is very compact and fully answers the purpose of dressing-nuts of any number of sides, 
 by using differently divided plates. In many engineering works, nuts of all numbers of sides are forged 
 iu swages made for the purpose ; the accuracy and beauty of finish of which is nearly equal to nuts 
 cut by the machine, and answer all purposes where extreme finish is not required, the expense of pro- 
 duction being at the same time very greatly diminished. 
 
 The subject of nut-cutting leads us now to the consideration of screw-keys, by means of which all 
 nuts of screws used in the connection of the different portions of machinery are adjusted to suit the 
 ever-varying exigencies of mechanical contrivances. The common screw-key with fixed jaws must be 
 so familiar to our readers as to render any description of it unnecessary, and we shall therefore point 
 out a few examples of attempts to remedy the defects of this most necessary instrument. In the dis- 
 section of any piece of machinery, even of the more simple species, we invariably find a multitude ot 
 different sized bolts, the nuts of which of course each require a key suited to its own particular size. 
 A reference to the number of gradations of size of nuts, given in a previous portion of our pages, will 
 immediately poiut out the necessity of some contrivance for dispensing with the number of these instru- 
 ments, and introducing an adjustable apparatus, by which a number of different sized nuts may be 
 worked without entailing the awkward drawback of keeping so many all but useless workshop ap- 
 pendages. 
 
 The earliest contrivance for this purpose is what is technically called a monkey, the use of which, 
 previous to the introduction of the more refined species of tools, was almost universal. 
 
 But a more elegant instrument for this purpose is the coach-wrench, which is equally applicable to 
 the working of nuts and all similar purposes. 
 
 Our example of this key, Fig. 3471, is capable of receiving nuts from the smallest size up to four 
 inches, and is of course sufficient of itself for all ordinary purposes. The end jaw a is in one piece 
 with the lever-handle b. The movable-jaw c is mortised to slide upon that portion of the lever between 
 
750 
 
 TOOLS. 
 
 3471 . 
 
 the end a and the fixed stop d\ it is held in its place when set for any nut by means of the second 
 lever e, which works on a centre-pin in the projecting portion of the jaw. This lever also carries a 
 projection at / by which it is jointed to a thin wedge, passing between the top of the lever b and the 
 interior surface of the slotted portion of the movable jaw. Thus, when the lat- 
 ter is set to the size of nut required, a slight pressure upon the side of the lever 
 e forces down the wedge, and secures the jaw immovably. (See Wrench.) 
 
 The peculiar merit of this species of key is, that all allowance for wear is 
 made up by the wedge, which will never permit any looseness in the jaw, as 
 the only difference caused by the wear of the surfaces in contact will be a greater 
 travel of the fixing wedge. Practical men who have made use of those keys 
 which are adjusted by means of nuts will at once see the value of this advantage. 
 
 Next to the turning-lathe in its importance to the engineer, the planing ma- 
 chine stands foremost in rank of constructive machines. The primary idea of 
 planing by machinery was doubtless brought into existence by the necessity 
 which constantly presents itself of diminishing the enormous amount of labor 
 expended in producing plane surfaces on wood by hand, as practised by means 
 of the common joiner’s plane. Next to the process of sawing, there is no opera- 
 tion connected with the working of wood, which consumes so much time, and 
 adds so much to the expense of the conversion of timber as the production of the 
 hand-planed surface. 
 
 The first attempt to obviate this difficulty with which we are acquainted, was 
 made by General Bentham, in 1791, who took out a patent for a method of effect- 
 ing this object. In this scheme, the plane or cutting-edge, which was movable, 
 was made of the full width of the board intended to be cut, and on each side of 
 it were fixed fillets which projected below the face of the plane, a distance equal 
 to the amount of the thickness intended to be taken off the board. Several 
 plans were adopted for obtaining a good surface from a very thin board, but the 
 whole scheme eventually proved all but abortive — the machine was never prac- 
 tically worked by mechanical power, but whether thus driven, or by the hand 
 of the attendant workman, the idea had still the advantage, that it exonerated 
 the latter from the charge which he had of his tool in the ordinary operation of 
 planing, rendering a common workman as useful as the skilful joiner for this 
 purpose. The next epoch in the history of mechanical planing is the improve- 
 ment produced by Mr. Bramah, who, in 1802, patented a method of producing 
 “ straight, smooth, parallel, and curvilinear surfaces on wood and other mate- 
 rials.” This invention embraced the original machine for producing spheres, the 
 principle of which is still preserved in all machines of a similar nature to the 
 present day. Bramah’s planing machine, as constructed for the Royal Arsenal 
 at Woolwich, gives us a specimen of an embodiment of his ideas at this period. 
 
 Here the cutters are attached to a horizontal disk keyed on a strong vertical 
 spiudle. This disk is put in rotation at a speed of about 90 revolutions per 
 minute, the material to be cut being attached to a sliding cast-iron bed, which is 
 moved by hydrostatic pressure. A pipe communicating with a hydrostatic press is carried in below th6 
 bed of the machine, and terminates in a plunger-barrel, the plunger of which carries a rack-geering 
 with a pinion on a rag-wheel shaft. This wheel is provided with teeth, over which a pitch-chain at- 
 tached to the table of the machine is carried. 
 
 In all planing machines as at present constructed, the cutter is invariably the fixed portion, the work 
 being passed beneath it in the act of cutting, by means of a sliding-table. The particular species of 
 planing machine which has been most lately introduced, is termed the hand-planing machine. 
 
 In Figs. 3477 and 3479 we have given three views of a simple and effective hand-planing machine, 
 as suited for small work generally, such as links and connecting-rod ends for locomotive engines, and 
 other portions of machinery where a plane surface of small extent is required. 
 
 The table of the machine is here supported in the usual manner, as employed in similar tools of a 
 larger class, upon a bed bolted to the top of two standards attached to the floor. The lower surface of 
 the table carries a rack M, which is driven by a pinion F, upon the shaft G, supported in bearings at- 
 tached to the fixed bed of the machine. Motion is given to this shaft in either direction, by the cross- 
 handle H, worked by hand in a similar manner as applied to small presses. 
 
 The cross-slide C is supported by two uprights bolted down to the bed ; this slide carries the tool-holder 
 D, which is traversed across the bed of the machine by means of the horizontal screw b. The automa- 
 tic action of the transverse feed motion of the cross-slide is effected by the movable stud S, attached to 
 the travelling-table ; this stud, being movable in a groove in the side of the table, is capable of being 
 set at any point in order to suit the required length of stroke for the work. The pressure of this stud, 
 upon a short lever keyed on the small shaft carrying the piece n, depresses it, and the latter, by its 
 connecting-rod r, acts upon the ratchet-plate K, upon the horizontal screw b. 
 
 The amount of travel thus given to the screw is varied by shifting the position of the sliding-studs in 
 the pieces m and n. The front plate of the tool-holder is provided with two short circular slots, through 
 which bolts pass from the back plate ; in this manner the tool may be set at any angle to suit the na- 
 ture of the work required. The tool-holder or cross-slide is raised or lowered to suit the circumstances 
 by the vertical screws//, driven by bevel-geering in the usual manner. 
 
 A somewhat similar but more useful machine of this species has been introduced by Mr. Charles 
 Walton, of Leeds. In this machine the bed is so arranged that it may be fixed upon the workman’s 
 bench, and may be driven either by manual or steam power. Immediately beneath the bed of the ma- 
 chine is placed a horizontal grooved disk, driven by bevel-geering, either from the pulley-shaft of the 
 
 
TOOLS. 
 
 751 
 
 workshop or by a winch. This disk is grooved directly across its upper surface for the purpose of re- 
 ceiving a pin, which is connected by a link with the lower surface of the short travelling-table. In this 
 manner a reciprocating motion is given to the table in the simplest manner, and the length of stroke is 
 capable of variation according to the distance of the pin in the horizontal grooved disk, from the centre 
 of motion. The feed motion of the cross-slide is effected by a stud fixed on the under surface of the 
 horizontal disk; this stud works a short lever keyed upon a shaft working in bearings attached to the 
 side of the bed. This shaft again curries a second lever outside the bed, and is jointed by a link to an 
 arrangement of ratchets. For all small machines, this method of giving motion to the table is decidedly 
 the simplest and most compact, and although the introduction of the disk has the effect of producing 
 a variable speed in the cutting, being greatest at the middle of its stroke and least at each end ; yet as 
 the disk is confined to machines of a short stroke, its diameter is not so great as to bring about a detri- 
 mental variation in the speed. Small machines of this species, ■which are quite an innovation in the 
 workshop, are now becoming indispensable where much small work is required, and have served in a 
 great measure to banish that most expensive of all tools, the file, and thus rendered an important ser- 
 vice in cheapening engineering work in general. So much indeed is this the case, that it is an estab 
 lished fact that different portions of machinery, the configuration of which is made up of curved and 
 plane surfaces, are now entirely finished by means of the lathe and planing machine, without the neces- 
 sity of touching them with the file. 
 
 As a spacimen of a step higher in the order of completeness and general usefulness in machines 
 of this kind, we must now refer the reader to Figs. 3080 and 3080 2 , where we have given very 
 complete views of the machine invented by Mr. Mylne, of Glasgow. Here tire system of working 
 the vertical and horizontal slides is similar to that made se of in the hand-machine, Figs. 3077 
 and 3078. 
 
 The chief peculiarities in the present machine are the arrangement of the geering for travelling the 
 table, and the great completeness of the tool-holder. The forward or cutting motion of the table is ob- 
 tained from the large pulley A, the shaft of which carries a pinion D geering with the large wheel E 
 upon the rack-pinion shaft. 
 
 This shaft carries two pinions geering with two racks of similar pitch bolted to the under side of the 
 travelling-table. These racks are so placed that each tooth of the one shall be opposite to each space 
 of the other ; in this manner the irregularity of motion so much complained of in ordinary rack-worked 
 machines, as producing a waved surface on the work, is to some extent avoided. A more effectual 
 method of attaining this end has been introduced by Mr. Collier, of Manchester ; this plan consists in 
 making the teeth of the rack and pinion on what is technically termed the step system, that is, each 
 tooth is divided in its breadth into three parts, each division being set a distance equal to one-third of 
 the true pitch of the teeth behind its neighbor. The practical result of this arrangement is, that although 
 the strength of the original coarse pitch is preserved, yet the teeth work with the steadiness due to a 
 pitch three times finer, or so many times less as the number of divisions of the teeth amounts to. This 
 plan is now universally adopted in all rack machines, as it is simple, easy of application, and completely 
 effectual. 
 
 This, although in our opinion not the best, is probably the most universally used species of driving 
 geering applied to planing machines. Of the two remaining systems, the chain and seme , the latter, for 
 excellence of workmanship, is decidedly to be preferred. Mr. Whitworth’s planing machine is perhaps 
 the most finished specimen of modern tool-making extant. 
 
 The principle of anti-friction rollers acted on by a screw, as a means of obtaining a rectilinear motion, 
 was first introduced by Mr. Whitworth, in 1835, when he employed it as a motion for the carriage of 
 the self-acting spinning mule. In his planing machine the rollers are placed parallel, face to face, on 
 opposite sides of the screw, their axes revolving in bearings attached to the under surface of the bed, 
 and their peripheries projecting into the spaces between the threads of the driving-screw. It will be 
 seen that each periphery has two opposite points of contact, acting alternately according to the direction 
 of motion of the screw, which, as it revolves, brings its threads to bear upon the rollers, causing them to 
 revolve, and at the same time to carry forward the table to which they are fixed. The friction which 
 would occur if the threads of the screw bore simply against a fixed nut, is thus transferred to the axes 
 of the rollers, where the velocity is reduced in the proportion existing between their peripheries and the 
 circumference of their axes. The proportion found to answer best for this arrangement is as 7 to 1. 
 The advantage which this mode of driving has over the common rack and the chain will be perceived a4 
 a glance, as not only is the motion rendered perfectly uniform, a condition essentially necessary to the 
 proper action of the cutter in producing a good surface, but the construction of the driving geering is 
 rendered to the last degree simple. 
 
 The arrangement of catches employed by Mr. Mylne is good, but tire geering connecting the catch- 
 shaft with the strap-fork is capable of much simplification. 
 
 Referring to Figs. 3080 and 3080 2 , it will be seen that there are two adjustable catches n n set in a 
 groove running along the side of the table ; these catches are not set in the same plane, but one projects 
 out beyond the other in order to suit the levers g, which are cast to a tubular shaft working loose on 
 the driving-shaft. When the table is moving forward one of the catches comes in contact with its lever 
 and turns it over, as seen in the end view of the machine. The boss of these levers again carries a third 
 lever connected to the weighted lever on the end of the bed, which again communicates by a shaft run- 
 ning along the side of the machine, with the strap-fork shaft 0; the latter thus causes the shift of the 
 straps from one pulley to the other, and reverses the motion of the table. Upon the return of the table, 
 the catch which has just acted now returns without coming in contact with its lever, as its former motion 
 has placed it out of its reach, having at the same time raised the second lever on the same shaft to an 
 upright position, so that it may be acted upon by the other catch at the contrary end of the table, when 
 the straps are brought back to their primary positions. 
 
 As a driving and reversing geer for small planing machines, Mr. Nasmy i h has applied the mangle- 
 
752 
 
 TOOLS. 
 
 wheel motion, so called from its adaptation as a continuous forward motion for common clothes-mangles. 
 It consists of a large disk, having near its circumference a circle of pins bolted through the metal at 
 right angles to its plane; these pins answer as a set of teeth, into which a small driving-pinion geers, 
 working alternately on the outside and inside of the teeth so as to effect the desired reverse motions. 
 In Mr. Nasmyth’s arrangement, the driving-pulley is keyed upon a light shaft passing transversely be- 
 neath the table of the machine. The contrary extremity of this shaft, which projects beyond the edge 
 of the bed, carries the mangle-pinion geering with the pins of the mangle-wheel. The latter is keyed 
 upon a central transverse shaft which passes beneath the table of the machine and carries a large chain- 
 pulley. Round this pulley a chain is passed twice, and its two extremities are passed round two fixed 
 pulleys placed at contrary ends of the bed, and attached to the opposite ends of the travelling-table. 
 The reversing of the mangle-wheel, and consequently that of the table, is effected in the following man- 
 ner : at two points in the circumference of the mangle-wheel, one or two of the pin-teeth are removed, 
 and a sloping guide or stud is placed at each point, so that when the driving-pinion arrives there, this 
 guide causes it to traverse in or out, as the case may be, to geer with the inner or outer sides of the 
 pins, under which conditions it is easy to see that the two contrary motions of the wheel will be the 
 result. The guide supporting the pinion-shaft is slotted horizontally to allow of the traversing of the 
 shaft as well as to prevent its running beyond the point of geer with the pins of the mangle-wheel, the 
 bearing on the opposite end of the shaft next the driving-pulley being arranged to swivel on a centre, 
 so as to permit of this motion. This movement of the pinion-shaft is also taken advantage of in giving 
 the feed motion to the cross-slide of the machine, being connected to the vertical rod carrying the catches 
 for the ratchet-wheel of the transverse screw. 
 
 This movement, although ingenious, is destitute of the ad- 
 vantage of an increased speed in the return stroke, consequent- 
 ly much time is lost by it when applied to single-acting ma- 
 chines. 
 
 The arrangement applied by Messrs. Nasmyth and Gaskell 
 to the rack-planing machines is a very convenient though 
 somewhat cumbrous motion. Fig. 3472 is a ground plan of 
 this geering, in which a is the forward motion driving-pulley, 
 keyed on the hollow shaft b, which carries a pinion c geering 
 with a large spur-wheel d. The latter is keyed directly on 
 the rack-pinion shaft e, shown in dotted lines passing beneath 
 the table of the machine. The backward-motion pulley/ is 
 keyed on the solid shaft, passing through the hollow one and 
 revolving at one extremity in the bearing g fixed on a pedestal 
 attached to the bed-plate, and at the other in the bearing k 
 bolted to the side of the bed. This latter shaft carries another 
 pinion k geering by means of an intermediate carrier-wheel, 
 with the spur-wheel l also keyed on the rack-pinion shaft. 
 
 The centre pulley is of course loose, serving merely to carry 
 the strap when the machine is stopped, and during the trans- 
 fer from the forward to the backward pulley. Thus it will be seen that the return stroke of the table 
 will be so much quicker than the cutting one, as the difference in diameter of the two wheels l and d, or 
 rather, as the ratio which exists between the wheels k and I and c and d. 
 
 The strap-fork is seen at m ; it is worked by catches fixed on the other side of the table, a connecting- 
 shaft from which passes beneath the bed where it is attached to the fork; n is a weighted lever for the 
 purpose of giving a sudden shift to the strap, so as to give the workman a better command over his 
 machine. 
 
 Of chain-worked planing machines, the modification introduced by M. Decoster, of Paris, is perhaps 
 one of the most complete. In his machine he has made use of the driving-geer as applied by Mr. 
 Whitworth to his screw-machines. In the example by M. Decoster, to which we refer, the chain- 
 motion is applied to give motion to the tool-slide, while the table of the machine remains stationary. 
 This plan is found extremely useful in planing heavy and unmanageable pieces of metal, as the latter 
 may be firmly secured to a foundation independent of the machine, while the tool alone traverses over 
 it ; and consequently no more power is absorbed by a heavy casting, than by the lightest possible piece 
 of metal. The driving geering before referred to is here placed alongside the bed of the machine, near 
 one end ; the pinion on the central bevel-wheel geers with a large spur-wheel, on a shaft passing trans- 
 versely across the bed of the machine, below the table. The latter shaft carries two rag-wheels, placed 
 near its two extremities just within the frame of the machine. Round each of these wheels is passed 
 an endless chain, which passes along the whole length of the machine, returning round a similar pair of 
 w’heels revolving loosely on studs at the contrary end of the bed. The upper length of this chain is 
 attached to the lower surface of a V-grooved slide, working in corresponding grooves planed in the 
 upper surface of the bed. This slide carries a second horizontal slide supporting the tool-holder in the 
 usual manner. The feed-motion of the cross-slide is ingeniouslv effected by two ratchet-catches attached 
 to the spur-geering on the end of the horizontal screw. The lower extremities of these catches are set 
 to come in contact with movable tappets attached to the fixed frame of the machine, so as to give the 
 proper amount of motion to the screw of the cross-slide. The method of attachment of the driving- 
 chains adopted by M. Decoster has the advantage of giving a steadier pull to the tool-slide than can be 
 obtained by the central mode of fastening, with a single chain. 
 
 The principle of the movable tool and fixed table has also been adopted by M. Cave and Mi - . Hick, of 
 Bolton. In M. Cave’s machine, the driving motion is given to the tool-slide by an endless strap. The 
 driving-pulley is placed immediately over the centre of the bed of the machine, the strap from whicn 
 passes below two fixed tension-pulleys, placed just beneath the driver, and thence round two fixed pul- 
 
l C uLS. 
 
 753 
 
 leys attached to the opposite ends of the bed. The attachment of this strap to the sliding-frame of tb6 
 tool is effected by passing the strap in contrary directions round two separate pulleys, each carrying a 
 pinion geering with a central driving-wheel. 'The shaft of the latter passes across the bed of the ma- 
 chine, and carries two pinions, geering with two racks, placed within the framing, and running along the 
 whole length of the bed. 
 
 The arrangement of the spur reversing-geer will be understood by referring to Fig. 3473, which is a 
 side view of the tool-slide, frame, and geering, with the driving-pulleys removed. A is the travelling 
 tool-slide, eairying the central driving-wheel B, keyed on the pinion-shaft — the shafts C C each carry a 
 loose driving-pulley, capable of connection by means of sliding clutch-boxes with the two pinions D D 
 These latter work loose on the pulley-shafts, and geer with the central wheel B, so as to drive it ir. 
 either direction accordingly as the clutch-boxes are set. 
 
 3173 . 
 
 Two povable inclined tappets are fixed to the bed of the machine, which alternately come in contact 
 with the lever E on the oblique shaft F, so as to move it in and out according to the motion of the slide. 
 The shaft F carries the two forks G, connected to the clutch-boxes of the pinions D D, which are placed, 
 one on each side of it, so that when the lever E is pressed upon by its tappets, the hold of the two 
 clutches is changed accordingly — one being thrown out of geer at the same time the other is put in. In 
 this manner, as the two pulleys on the pinion-shafts revolve in different directions, a reciprocating mo- 
 tion is given to the travelling-slide. 
 
 The cross-slide of this machine is provided with two tool-holders, one on each side, so as to cut in both 
 directions ; this improvement effects a great saving of time, as the return stroke is rendered equally as 
 effective as the forward one. 
 
 In Mr. Hick's movable tool-slide machine, the traversing motion is given to it by means of steel belts. 
 The driving-pulley of the machine is alternately worked by a cross and open strap ; the shaft of this 
 pulley is connected, by means of spur-geering, with a transverse shaft carrying two pulleys working 
 outside the frame of the machine. These pulleys each carry an endless steel belt, running along- 
 side the frame, and passing round two similar pulleys placed at the contrary extremity of it. The 
 steel belts are attached to projecting levers on the cross-slide by means of tightening screws, so as 
 to communicate an alternate motion to it, accordingly as the open or crossed strap is working on the 
 driving-pulley. 
 
 As the speed of the travelling-table of this machine is the same in each direction, it is arranged to 
 cut both ways, by the adaptation of Mr. Whitworth’s revolving tool-holder, subsequently described. 
 
 It is a' matter of considerable importance in planing machines, to have a compact arrangement at 
 command, both for reversing the motion of the table, and also for giving the self-acting feed-motion to 
 the cross-slide. As regards the reversing motion, in planing delicate or complicated work, it is often 
 requisite to be able to stop the motion of the table within the shortest possible limits, as, for instance, 
 in planing up to an abrupt shoulder ; in such a case, if the tool does not proceed sufficiently far, a sur- 
 face of metal is left which must be removed by some more laborious means ; or, on the other hand, if it 
 proceeds a little too far, the tool strikes against the obstacle and causes an injury either to the work or 
 to its own geering. In small machines this is easily avoided, by the use of the crank or grooved disk, 
 which allows of the greatest exactitude in the length of travel ; but in machines of the larger class we 
 are driven to some other expedient to attain this end. Where the change of motion is effected by the 
 pulley-belt, the simplest and most effective system of quick stoppage is the addition of the weighted 
 balance-lever attached to the strap-fork ; the sudden fall, in either direction, of this weight causes an 
 instantaneous motion of the strap, and stops the table within very short limits. Where still greater 
 nicety is required, possibly the addition of a movable clutch-box may be of some assistance Soma 
 Vol. II. — 48 * 
 
754 
 
 TOOLS. 
 
 maker's, indeed, have applied Ihe clutch-box instead of the shifting-strap, the clutch being arranged to 
 throw the two side bevel-wheels in geer alternately with the centre one. 
 
 Asa compact and efficient self-acting reversing and feed motion, we give that adopted by Mr. Whit 
 worth, as one of the best. Fig. 3474 is a side elevation of the apparatus ; a is the table of the planing 
 machine, on the side of which, at the centre, is screwed the fixed catch b, which, in the course of work- 
 ing, alternately comes in contact with the movable catches cc, adjustable on the shaft d which runs 
 alongside the table, sliding in the bearings e e at each end of 
 the frame. This shaft carries a third adjustable catch/, con- 
 nected with a short lever cast on the boss g working loose on 
 a stud screwed to the frame. The same boss has also cast 
 upon it a second lever /t, at right angles to the former one, 
 the end of which works in a slot in the scrap-fork i. The lat- 
 ter oscillates on a centre attached to the bed at k ; when the 
 catch b comes in contact with one or other of the studs c, the 
 shaft d is carried along laterally, and gives motion, through 
 the arrangement of levers just described, to the strap-fork so 
 as to shift the strap from one pulley to the other, and reverse 
 the table. 
 
 The self-acting feed-motion of the cross-slide is effected in 
 the following simple manner : on the sliding shaft or rod d a 
 few rack-teeth l are cut, which geer with a segment of a spur- 
 wheel keyed on the shaft m, working in bearings screwed to 
 the upright frame of the machine, and carrying the eccentri- 
 cally-grooved disk n, which revolves with it ; o is the vertical 
 rod carrying the ratchet-catches for working the horizontal 
 screw of the cross-slide : it is guided by a bearing p screwed 
 to the frame, and carries at its lower extremity a pin working 
 in the eccentric slot of the disk n. Thus when the rod d re- 
 ceives its motion from the catch b, at the termination of the 
 stroke of the table, its short rack causes the disk n to make a 
 portion of a revolution, so as to raise or depress the rod o 
 by means of the eccentric groove. This motion is at once ef- 
 fectual and easy of application, besides possessing that great 
 desideratum in all tools, compactness. 
 
 We now come to the consideration of tool-holders. The 
 specimen of a tool-holder given in Mr. Mylne’s machine, is one 
 of the more complicated variety, being provided with a double 
 set of slides and appropriate screws, for the purpose of plan- 
 ing at two different angles with one adjustment of the tool. 
 
 The saving in time, however, by this arrangement, is more 
 than counterbalanced by the increased cost of the tool-box, 
 
 3475. 
 
 and the disadvantage which it entails upon the machine, by throwing the point of resistance in cutting 
 so far from the surface of the supporting frame as to render the cutting action unsteady. 
 
 A somewhat simpler modification of the same variety of holder is represented in Fig. 3475, where the 
 
TOOLS. 
 
 
 (05 
 
 edf-acting down cut motion is obtained by one screw; a is a transverse section through the cross-slide 
 of the machine, to which is fitted, by dovetails, the horizontal sliding-plate b. The latter again carries 
 the down-cut slide c, being attached to it by dovetail-headed bolts working in a circular groove in the 
 former. The slide c is fitted with a central screw carrying a nut fixed on the front sliding- plate d, so 
 that the latter may be moved at any angle to the bed of the machine according to the angular position 
 of the screw; e is a front plate, checked into the slide d, to which is hinged the tool-holder/, carrying 
 the tool as shown at g. 
 
 The self-acting feed-motion is given to the screw in the plate c by bevel-geering, similar to that em- 
 ployed in Mr. Mylne’s machine. The hinge at the upper end of the tool-holder is for the purpose of 
 nllowing the tool to give way in case it comes in contact with any obstacle during the return stroke of 
 the machine. In all properly constructed tool-boxes, the mechanism is arranged to lift the tool out of 
 the way at each return stroke, so that it never rests upon the surface of the work in the back motion. 
 This is effected by a separate transverse screw placed parallel to the main traversing screw, and worked 
 by the same geering. In Mr. Bodmer’s tool-boxes this screw carries a nut with a slotted projection fit- 
 ting to a pin in the upper end of the front plate, which oscillates loosely on a fixed centre. The nut 
 being carried along with the tool-slide by the revolution of its screw, remains always immediately above 
 the centre of the tool-holder; at the termination of a stroke, the reversing geering is so connected with 
 the screw as to give the latter a lateral sliding motion, the nut upon it then moves the front plate by 
 the pin in its upper side. This plate carries a small inclined pin, which in its motion presses against 
 the front of the hinged tool-holder, thus raising it out of connection with the work. 
 
 The self-feeding down-cut motion is also given by the same oscillating plate. The latter is provided 
 with a toothed sector screwed to it near its lower extremity, and geering with a small bevel-pinion on 
 the down-cut screw-spindle. The latter being fitted with a ratchet-wheel, receives at each stroke of the 
 machine an amount of motion proportioned to the material to be cut. This is probably one of the most 
 complete and effective of all single-acting tool-holders, and is a good specimen of the high degree of 
 eminence which Mr. Bodmer has attained as a maker of constructive machinery. 
 
 In addition to the common rectilineal planing machine, machinists have of late years found a power- 
 ful auxiliary in the circular machine ; this may be defined, in general terms, as a lathe with a vertical 
 spindle. The tool is either fixed or movable, the former being the preferable and more general ar- 
 rangement. The advantages which these machines possess over common turning-lathes, are, firstly, the 
 greater facility of adjustment of heavy castings preparatory to planing them ; and secondly, the greater 
 latitude they allow for acting on masses of metal of great diameter, as the driving-wheels of locomotive 
 engines, fly-wheels, &c. Of this species of tools, perhaps Mr. Bodmer’s modification stands highest in 
 the scale of usefulness. It consists of a heavy foundation plate, in the centre of which a strong vertical 
 spindle revolves, having a horizontal circular table of large diameter keyed upon it, and provided in the 
 usual manner with slots for fixing the work. The fixed cutter is held in a tool-box precisely similar to 
 that adopted in the common planing machines. It is placed on a strong horizontal cross-slide, which is 
 adjusted to work freely in a vertical direction upon two upright frames, placed one on each side of the 
 revolving-table. The tool-holder being fitted with a down-cut motion, is readily adjusted with great 
 ninety to suit the work, besides which its horizontal motion on the cross-slide, combined with the verti- 
 cal motion of the latter upon the uprights of the frame, permit the tool to be set to any portion of the 
 radius of the table. The machine is fitted with a self-feeding motion ; this is found very serviceable in 
 turning up the tires of locomotive and carriage wheels, the rims of small fly-wheels, <fce. Machines have 
 been constructed which combine the advantages both of the rectilineal and circular machines, with a 
 view to the finishing of more complicated work than can be effected by either of these separately. The 
 machine is provided with a rectilineal sliding-table, as ordinarily used, supported on a fixed bed. A 
 horizontal shaft passes transversely below the bed, and carries a plain sector of considerable radius, to 
 which a chain is attached, and is connected to the opposite ends of the table. Motion is given to this 
 sector by a plain grooved disk, as usually applied to slotting machines ; this is driven by over-head 
 geering, supported by the upright framing which springs from the bed of the machine. The pin of this 
 disk is attached by a suitable connecting-rod to a crank keyed on the extremity of the shaft of the sec- 
 tor, which thus communicates a reciprocating motion to the table, of a length dependent on the position 
 of the pin in the radius of the disk. 
 
 When continued circular work is required, the driving disk is thrown out of geer, and the driving- 
 shaft is connected with an upright spindle revolving in bearings attached to the upper framing of the 
 machine, and carrying an adjustable cutter in a projecting arm at its lower extremity. This cutter is 
 provided with suitable slides, by which it may be set at any required distance from the centre of motion 
 of the spindle, so as to act upon any given circle. When thus arranged it may be used as a powerful 
 boring machine, by detaching the facing cutters, aud fitting the proper tools as applied to the usual bor- 
 ing bars. When the combination of the straight and circular movements is required, as for finishing 
 the flat sides and circular ends of strap-links, ifcc., both movements are effected by the same driving- 
 shaft as follows : — On the end of the driving-shaft are keyed two toothed sectors, arranged to give al- 
 ternately a semi- revolution to the wheel on the driving disk for the rectilineal motion, and that on the 
 train for giving the circular motion to the cutter-spindle— each wheel being alternately held by a de- 
 tent while the other is being driven. In this manner various kinds of work may be finished in a very 
 superior manner, such as the plane and circular surfaces of plummer-blooks, connecting-rod straps, Ac. 
 
 In addition to these two descriptions of machines for obtaining a plane surface, a third species for 
 planing curves has latterly filled an important office in the engineer’s workshop. The tool to which we 
 refer is the compound machine by Messrs. Nasmyth and Gaskell. This little machine forms another 
 link in the catalogue of automatic contrivances for superseding the delicate manipulations of file labor. 
 By its assistance the circular ends of levers, connecting-links, &c., are correctly cut out, and finished with 
 a degree of celerity that sets manual labor at defiance. The essential principle of the machine is iden- 
 tical with a slotting machine with a horizontal tool movement, the tool-slide being worked in a similar 
 
756 
 
 TOOLS. 
 
 manner by a circular slotted disk. In planing the circular ends of levers, the., the work, after being 
 drilled, is fixed on an ingenious adjustable mandril, with its rectilineal surface in a line with the direc- 
 tion of the traverse of the tool. A self-feeding motion causes the work to revolve slowly in the action 
 of cutting, similarly to the same arrangement in the slotting machine. By detaching this geering the 
 tool becomes available for the production of plane surfaces at any angle by an appropriate adjustment 
 of the tool-holder — thus it unites the offices usually consigned to separate tools, and is a very useful 
 auxiliary to the engineer. 
 
 Though not in immediate connection with the subject of planing, we may here mention Mr. Bodmers 
 stand-cutting machine. This tool is a species of planing machine, provided with a revolving cutter, and 
 is used for the purpose of cutting out the recesses in the small stand bearings, ifcc., in cotton and other 
 machinery, a species of work which requires the utmost precision and exactitude of management. In 
 preparing and fitting up the supporting pedestals used for the rollers of spinning machinery it is essen- 
 tially necessary to preserve their line of bearing perfectly level, otherwise the rollers will undergo an 
 injurious strain in the working. To accomplish this in a speedy manner, Mr. Bodmer fixes a row of 
 pedestals upright on a movable bed, constructed like an ordinary planing machine. The upright fram- 
 ing in the centre of the machine carries a revolving cutter, similar to the steel cutters used for cutting 
 the teeth of wheels ; the row of pedestals, which are placed in a line with the motion of the bed, are 
 then passed slowly beneath the cutter, thus securing an accurate adjustment of the height of each. 
 
 A machine similar in principle is used for fluting the wooden rollers of flax machinery, mechanism 
 being introduced for the purpose of causing the rollers to make a portion of a revolution after the cut- 
 ting of each groove. 
 
 Slotting machines, in their general principle of action, may be defined as planing machines with 
 movable tools. The period of their introduction to the workshop dates among the latest of the automa- 
 tic tools of the day, as, until a short time back, the species of work now executed by them was entirely 
 performed by the file and chipping-tool. As a finished specimen of this tool we may refer the reader 
 to Messrs. Caird & Co.’s machine, Figs. 3337, 3338, 3339, 3340. 
 
 The method of transmitting motion from the driving-gesr to the reciprocating tool is here very simple, 
 and the machine, as a whole, has a very handsome appearance. The table, in addition to the usual rec- 
 tilineal and circular motions, is provided with apparatus for setting it at any angle to suit the different 
 varieties of work. This angular motion is useful in cutting the key-seats of wheels, where a slight in- 
 clination is necessary to suit the shape of the fixing-key. 
 
 In such a machine as the one before us, it is evident that the size of the work capable of being oper- 
 ated upon by it, is circumscribed by the distance from the cutting centre to the edge of the supporting 
 pillar. If this distance is increased in order to suit the dimensions of wheels and castings of a large 
 size, a greater disadvantage ensues, namely, an increased amount of unsteadiness of action. Messrs. 
 Nasmyth & Gaskell have remedied this disadvantage most efficiently by doing away with the support- 
 ing framing of the machine, and causing the tool to cut from below upwards. The machine is, as it 
 were, entirely reversed in this modification, the driving disk and geering connected with the slotting-bar 
 being placed under ground in a pit made for the purpose. The cutting end of the slotting-bar projects 
 upwards, through a fixed cast-iron table on the floor of the workshop, upon which the work is laid in 
 the act of slotting. As in this arrangement there are no supports to interfere with the work on the 
 table, it is evident that this tool possesses an unlimited range of action. In another modification by the 
 same firm, this object is attained by supporting the tool-slide in a bottom-plate attached to the floor, to 
 which are attached four strong pillars, carrying a square table for the support of the work, at the height 
 required for the convenience of the workman. The driving-geer, in this instance, consists of a horizontal 
 shaft, passing under the table, near the level of the floor, driven by a strap, and carrying a pinion geer- 
 ing with a large spur-wheel, which, at the same time, serves to communicate the reciprocating motion 
 to the slotting-bar, being grooved across one side, for the purpose of receiving the traversing-pin of the 
 connecting-rod. The self-acting motion of the table is extremely neat and convenient. The spur-wheel 
 shaft carries a small eccentric, the rod of which communicates with the ratchet-wheels of two shafts 
 running horizontally at right angles to each other, beneath the movable sides of the table. Each of 
 these shafts carries screws, one of which, passing beneath the centre of the table, gives the rectilineal 
 motion, while the other geers with the screw teeth cut round the circumference of it, and, consequently, 
 traverses the table in a circular direction. 
 
 We have already discussed the philosophy of the true form of cutting edge for drills, as well as the 
 minor species of tools of this class ; it remains for us, therefore, now to enter upon the construction of 
 what are more properly termed drilling machines. The varieties of these useful machines, as used by 
 the engineer, are so numerous, that we can only find space to touch upon a few of those best adapted 
 to the wants of the workshop. Practically speaking, drilling machines are divisible into two classes 
 only, namely, the common vertical pillar, or wall-side drill, and the radial machines. 
 
 For a good example of the former of these varieties we may refer the reader to the detailed views in 
 Figs. 1122-1128, of Mr. Whitworth’s vertical drill. This machine, which probably takes the first rank 
 in its class, is independent, being provided with its own separate frame intended to be screwed to the 
 floor without the additional support of a pillar or wall. Motion is communicated to the drill-spindle by 
 an arrangement similar to the back geer of a lathe, contained in an opening in the upper portion of the 
 frame. The rectilineal feed motion of the drill-spindle is self-acting ; it is a beautifully ingenious ar- 
 rangement, and is pre-eminently deserving of attention. The upper portion of the spindle between its 
 bearings is screwed for the purpose of geering with the inclined teeth of a pair of worm-wheels, placed 
 one on each side of it ; the axes of which work in bearings attached to the front of the frame. A com- 
 pact friction-clip worked by a vertical screw from below embraces the projecting ends of these axes, by 
 which arrangement the revolution of the wheels may be completely stopped when requisite. Thus, we 
 will suppose the tightening screw of the friction-clip to be screwed up so that the latter holds the worm- 
 wheels firmly in their position ; it follows, then, that if the drill is set in motion, the threads upon the 
 
TOOLS. 
 
 757 
 
 spindle will act upon the teeth of the worm-wheels exactly as in a nut, and a quick descent of the spin- 
 dle will be the result. If now the friction is slightly relaxed, then the speed ot the descent of the spin- 
 dle will have diminished so much as is due to the slipping round of the worm-wheels. In this manner 
 any amount of feed motion may be communicated to the spindle with a nicety unattainable by any other 
 means, so that the varying hardness of the metal under action may be immediately accommodated by 
 a speed exactly suitable for cutting most advantageously. The table ot the machine is provided most 
 completely with all the requisite movements, and may be raised or lowered to suit the work by a pinion 
 working in a vertical rack attached to the front of the frame. 
 
 In Figs. 3652 to 3659 we have given complete views of Messrs. Nasmyth & Gaskell’s drilling-ma- 
 chine, which differs from the last specimen in the fact of its being destitute of a self-acting feed motion. 
 The downward pressure necessary for the feed of the tool being given by the pressure of the foot act- 
 ing on a bottom lever, which is connected by a vertical rod at the back of the frame, with a second 
 lever working on a bearing at the top. The front end of this lever works a sliding bearing fitting on 
 the top of the spindle, which thus receives a downward motion according to the pressure of the foot, the 
 counter- weight on the back end of the lever bringing up the spindle again, on the lever being released 
 from the pressure of the foot. This, as an independent variable motion, is very convenient, though in- 
 ferior in nicety to that used by Mr. Whitworth. 
 
 Fig. 3476 is a front view of the self-acting feed motion 
 applied by Mr. Lewis, of Manchester, to a wall-side drill. 
 
 Here the vertical spindle a carries a bevel-wheel b, into 
 which a second bevel-wheel c on the driving cone-shaft 
 geers. The spindle works in two bearings d d, attached 
 to a vertical plate bolted to the wall. A small spur-wheel 
 e is keyed on the spindle, a little above the lower bearing ; 
 this wheel geers with a second wheel/, which carries a 
 sliding bush g, so that it may be thrown in and out of geer 
 with the driving-wheel e at pleasure. The shaft li, carry- 
 ing this latter wheel, passes up the side of the drill, and 
 carries a second spur-pinion k at its upper extremity, geer- 
 ing with a large wheel l , the bush of which carries a nut 
 working on the screw m on the spindle. 
 
 This motion may be driven by hand at pleasure by dis- 
 connecting the wheel f and working a hand-wheel fixed on 
 the spindle h. 
 
 This may be taken as a specimen of the best kind of 
 self-feeding motions: it is compact, effective, and inexpen- 
 sive. 
 
 Of pillar drills, the modification introduced by Messrs. 
 
 Randolph, Elliot ifc Co., of Glasgow, is one of the most com- 
 pact. This drill is certainly the simplest and most gener- 
 ally applicable of its class, its component parts being con- 
 fined to a set of brackets to carry the drill-spindle, without 
 any additional frame, the office of which is supplied by any 
 of the pillars of the workshop. The spindle-brackets, as 
 well as those for supporting the table, are clamp-bolted 
 to the pillar — the spindle being worked either directly 
 through a speed cone or by double geering, as applied to 
 lathes generally. The self-acting feed motion in its gen- 
 eral details is similar to that of Mr. Lewis. The table is 
 provided with a strong central foot, to which two project- 
 ing brackets at the foot of the pillar are bolted ; it is thus 
 fixed immovably, and so far lacks the important advan- 
 tage possessed by a movable table. In some varieties of 
 drills the feed motion is confined entirely to the table, 
 which is worked by a rack and pinion movement, its weight 
 being balanced by a counterpoise attached to a chain pass- 
 ing over a pulley on the top of the frame. In drills in- 
 tended for boring to a considerable depth, this arrangement may have the advantage of steadiness of 
 action, otherwise the movable spindle is in every respect preferable. 
 
 In Figs. 3650 and 3651 we have given two views of Mr. Whitworth’s modification of the second class 
 of drilling machines, the radial drill. A reference to this drawing will show that it is an arrangement 
 on a principle quite distinct from that of the ordinary drilling machine. In the radial drill the motion 
 of the spindle is not confined to the vertical direction, but is provided with a lateral motion, whereby it 
 may be set to any portion of the work within the limits of the radial arm, thus superseding one of the 
 rectilineal motions of the table, which in this arrangement need only travel in one rectilineal direction 
 beneath the drill. This machine is likewise provided with the same feed motion as applied by this 
 maker to his ordinary vertical machine. 
 
 Messrs. Hick make use of a somewhat different arrangement of driving and feed geer. The central 
 frame of this machine consists in a short hollow circular bracket, having a nut fitted on its upper end 
 for the purpose of receiving a strong square-threaded screw, which carries the radial arm for the tool- 
 slide. The vertical motion of the drill is therefore not confined to the motion of the spindle in its own 
 bearings, but the whole radial arm is capable of a considerable vertical movement by turning the nut 
 on the central screw. The fast and loose pulleys for the driving geer are placed on a vertical shaft 
 
 3476. 
 
758 
 
 TOOLS. 
 
 working in a bearing on the top of the radial arm immediately over the centre of the screw — motion 
 being communicated from it to the drill-spindle by means of bevel geer as in Mr. Whitworth’s machine 
 The additional horizontal traversing motion of the spindle is effected by means of a pinion keyed on a 
 hand-wheel shaft and geering into a rack on the radial arm ; the downward motion for the feed is given 
 by hand by means of an overhead ratchet lever connected to a ratchet-wheel on a short horizontal shaft, 
 over which a chain connected to a cross-head on the drill-spindle is wound. A rod from this lever is 
 brought within the reach of the workman, so that he can depress the spindle at pleasure, the upward 
 motion being accomplished by means of a counter-weight attached to a chain-pulley on the ratchet- 
 wheel shaft. A somewhat similar mode of central movement has been adopted by Mr. Bodmer in his 
 improved radial drill. Here the main central support consists of a strong hollow circular pillar provided 
 with wrought-iron centres at top and bottom, upon which it revolves. A screw passes down the centre 
 of this pillar, and carries a nut attached to a bevel-wheel on a bracket projecting through a vertical slot 
 in the pillar. This bracket is screwed to the radial arm of the machine, and is raised or lowered by a 
 lever handle on a shaft carrying a bevel-wheel geering with the one referred to above as carrying the 
 nut on the central screw. The driving geer consists of an overhead horizontal shaft carrying a bevel- 
 pinion working in a large bevel-wheel on the top of the supporting pillar ; the latter carries a spur- 
 wheel geering with a pinion on a vertical grooved shaft working in bearings attached to the pillar. 
 This shaft carries a sliding Devel-wheel provided with a key to fit its groove, so that it is at liberty to 
 rise and fall with the radial arm without revolving loosely on its shaft. From this bevel-wheel motion 
 is transmitted by a train of geering to the drill-spindle in the radial arm, in the usual manner. The 
 self-acting feed motion is highly ingenious and effective ; the horizontal driving-shaft of the radial arm 
 carries a small band-pulley from which motion is given to a short horizontal worm-wheel shaft, the worm 
 of which geers with a wheel on an upright shaft carrying a long pinion on its upper extremity. This 
 pinion geers with a spur-wheel attached to the nut of the top driving-screw of the spindle, which thus 
 receives a regular descending motion according to its boring speed. By detaching this geering, the 
 long pinion may be worked by hand at pleasure. Although for some specific purposes this species of 
 drill is highly useful, yet where great accuracy is required, it is inferior to the ordinary pillar or wall- 
 side machine on account of its want of steadiness and rigidity. 
 
 Boring machines are, abstractedly, merely modifications of the larger class of drills, and are applied 
 to the same purposes. 
 
 They are divisible into two classes, namely, horizontal and vertical machines. The latter species of 
 machine is generally considered to be the most useful for engineering works, and there is no doubt that 
 it possesses some great advantages over the former one. In the first place, the vertical position of the 
 cylinder entails no transverse strain upon it, which would be pretty considerable in a cylinder of large 
 «ize placed horizontally. Such a strain would, of course, render the action of the tool extremely uncer- 
 tain, and would detract materially from the required true surface. Again, the boring-bar may in some 
 sort be considered as liable to the same disadvantage which its vertical position remedies. Lastly, the 
 action of the cutters is not at all impeded by the presence of the turnings, which immediately fall to 
 the foot of the cylinder and leave the cutter free at each progressive step. The most convenient and 
 secure place for a boring-machine of a large size is the corner of the workshop, where the two angular 
 walls form firm supports for the framing of the machine. 
 
 Messrs. Nasmyth & Gaskell have produced a useful tool of this particular class; the framing consists 
 of a stout circular bottom casting, provided with a clamping ring for holding down the cylinder in the 
 act of boring, and an overhear! cross-beam for carrying the upper extremity of the boring-bar spindle. 
 The footstep of the boring-bar's placed beneath the ground floor of the shop, where, as well as for a 
 portion of the driving geering, an excavation is purposely made to receive them. The driving-pulleys 
 are placed outside this pit ; they communicate with an oblique shaft, which carries a worm on its end, 
 geering with a large worm-wheel near the foot of the boring-bar, to which motion is thus given. The 
 cutter-boss is traversed in the usual manner by a longitudinal screw in the bar, but a different method 
 is adopted for returning it after the first rough cut. Immediately this is accomplished the cutter-boss 
 is detached from the nut of the traversing screw, and is hauled up alone by a small crane attached to 
 the machine ; the cutters are then reset and the finishing cut is gone over. 
 
 A machine somewhat similar, but of gigantic dimensions, has been constructed by the same engineers 
 for the Great Western Steam Navigation Company, for the purpose of boring out the cylinders of the 
 Great Britain steamer. 
 
 In this machine, the entablature carrying the upper end of the boring-bar is supported on two mas- 
 sive pillars of masonry, placed one on each side of the boring-bar. The feed-motion of the cutters is 
 novel and ingenious in the extreme ; it consists, primarily, of an internal screwed collar fixed on the upper 
 surface of the entablature, and surrounding the boring-bar. A train of geering, terminating in a pinion 
 working into a rack running down the side of the boring-bar, is attached to the latter and revolves with 
 it. The first wheel of the train is a species of crown-wheel, its teeth being set at right angles to its axis 
 of motion ; this geers with the internal threads of the screwed collar before mentioned, so that by this 
 means, the train is set in motion by the revolution of the bar, and the cutter-boss, which is attached to 
 the lower end of the rack, is raised and lowered at pleasure. 
 
 Mr. Walton, of Leeds, has introduced a highly effective boring machine, with columnar framing in- 
 tended principally for boring the apertures in the tube plates of locomotive engines. The machine is 
 capable of drilling a series of parallel holes on a surface of five feet square, without refixing the object 
 under operations, the tool-holder and the table being movable at right angles to each other. This bor- 
 ing machine may be considered as a magnified drill, as the spindle is fed longitudinally, no cutter-boss 
 being attached. The framing consists of two plain columns, coupled at the top by a suitable entabla- 
 ture, and carrying two other transverse beams for the support of the drill-spindle and driving-gear 
 The self- feeding motion is similar to that illustrated by Fig. 347 6, and it may also be worked by hand 
 in the same way 
 
TOOLS. 
 
 759 
 
 The spindle is capable of a vertical travel of 24 inches, and is consequently well suited for boring 
 out the small cylinders of locomotives, Ac., as well as for boring out the eyes of carriage and othei 
 wheels, which it will receive up to 6 feet in diameter. 
 
 Figs. 2547 and 2548 now introduce to us the second species of boring machine, the horizontal one 
 Our example is intended for the heaviest kind of work in the engine-shop, and is purposely very strongly 
 constructed. The arrangement of the train of driving-geer allows of a considerable latitude of speed 
 of the cutters ; the changes by alteration in the geering permit of as small a variation as 1 to 1-J, so 
 that any speed within the entire range may be obtained within Jth of the one required. In Figs. 2542 
 and 2543 we have given a still more complete tool by Messrs. Kinmonds, Hutton, and Steel, of Dun- 
 dee. It is provided with a slide-rest and tool-holder, and thus becomes available for turning as well 
 as boring. This is a very valuable machine, and where ground space is an object in the w 7 orksbop, will 
 be found highly convenient from the saving of space which it effects. The proper speed at which the 
 cutter should pass over the surface of the metal may be stated as from 6 to 7 feet per minute, though 
 this must, of course, be dependent in a considerable degree upon the relative hardness of the metal. 
 Until a few years back, cannon were cast with a core, in the same manner as steam-engine cylinders 
 are now. Experience has, however, pointed out the fallacy of this method, as it was impossible to 
 make a true bore, the cutter having a tendency to follow the inaccuracies of the yet rough surface. In 
 addition to this, the guns, when cast hollow, have a tendency to become spongy near the inner surface 
 of the bore. To remedy these defects, all ordnance are now cast solid, and thus the metal is rendered 
 closer in the grain, and any “ blown” or defective parts are confined to the centre of the metal, when 
 they are cut out in boring. Guns are bored in a manner directly the reverse of that employed in pre 
 paring steam-engine cylinders. The bed of the machine employed for boring out guns is provided with 
 two pedestals having bearings of a considerable diameter, in which the gun itself is caused to revolve, 
 the cutter remaining stationary on a sliding-carriage. The cutter is kept up to its work by means of a 
 weighted-lever, attached to a pinion-shaft beneath the bed of the machine. This pinion geers with a 
 rack attached to the cutter-carriage, which is thus impelled forward towards the gun, until the weights 
 in the loaded lever reach near the ground, when the lever is raised and the weights reset by a ratchet- 
 wheel. 
 
 The punching machine, from being confined to the tin-smith and ornamental metal-worker’s shop, has 
 latterly become an instrument of no slight importance to the engineer, whose ponderous adaptations of 
 this tool excite the greatest wonder in the mind of a stranger unaccustomed to their operations. Here 
 the punch or cutting tool seems to pass through an enormously thick piece of cold metal, as if the latter 
 was so much pasteboard, the whole of the operation being conducted without producing the least noLe. 
 
 In Fig. 3174 we have given various views of a compact and convenient punching machine, constructed 
 by Messrs. Caird, of Greenock. The framing consists of one solid casting, open in the centre for the 
 reception of the large driving bevel-wheel on the horizontal puncliing-shaft. The driving geering and 
 fly-wheel for steadying the motion are placed overhead, so as to be completely out of the way, and 
 leaving a clear space all round the machine for the workmen. The shearing and punching apparatus 
 being on two opposite sides of the machine, these two operations may be conducted at the same time, 
 without any risk of confusion among the men. 
 
 -Of late years, the system of riveting by steam power has made rapid progress, and promises in all 
 large works to supersede entirely the old laborious and noisy process of riveting by hand. We are in- 
 debted to Mr. Fairbairn, of Manchester, for the introduction of this machine, who invented it upon an 
 emergency to supply the loss of a set of hand riveters who had left their employment on account of 
 some business disagreement. Mr. Fairbairn’s machine, see Figs. 3226-7, is a highly elegant and efficient 
 apparatus. The essential principle of the machine is that of the knee-joint lever, as applied to printing- 
 presses. Motion is given to this lever by means of a revolving-cam driven by suitable geeriug ; this 
 cam acting upon a loose anti-friction pulley, placed at the centre joint of the lever. The saving by the 
 use of this machine is very great, and, what is of no small consequence, the whole operation of riveting 
 is performed in silence ; the system of pressure, too, has the advantage of leaving the metal of the rivets 
 in its original state. By the old plan of hammering, the rivets were extremely subject to crystalliza- 
 tion, and as a natural consequence, numbers of the heads gave way in the finishing. 
 
 We have seen a section of two pieces of boiler-plate riveted together in this manner, the section be- 
 ing taken through the centre of the rivet, and it was remarkable to see how the pressure of the ma- 
 chines had forced, as it were, the metal of the rivet into all the interstices of the plates, incorporating 
 the two so as to be scarcely distinguishable from one piece of solid metal. M. Lemaitre, of Paris, has 
 successfully combined the two operations of riveting and punching, in one machine, which he actuates 
 by the direct pressure of steam, without the intervention of additional geering. We have detailed this 
 machine fully in Fig. 3220, where also is shown M. Lemaitre’s arrangement for riveting long and nar- 
 row tubes, which is very ingeniously contrived. 
 
 Messrs. Schneider, of Creusot, in France, have also applied the direct action of the steam to the pur- 
 pose of riveting. Their modification closely resembles in principle the plan adopted by Mr. Fairbairn ; 
 the piston of the steam cylinder is jointed directly to the central joint of the “ knee” combination, and 
 the rise and fall of the former of course gives a lateral traversing motion to the compressing ferrule. 
 Latterly, also, Messrs. Garforth, of Duckintield, have applied the pressure of steam in a still more direct 
 manner. The shaft carrying the compressing ferrule, for forming the rivet, is at the same time the 
 piston-rod. the cylinder of which is placed horizontally in the frame of the machine. It is evident that 
 in this plan, as no mechanical power intervenes between the point of action of the steam, and the point 
 of resistance, a very large cylinder must be used to produce the required pressure, and consequently a 
 large amount of steam must be used at each stroke of the riveter. There is no doubt but that this 
 machine may be arranged to work at a high speed, but we think it must fail to work so ecenomicahy 
 as the machines worked by a small piston assisted by additional mechanical power. 
 
 Mr. Walton, of Leeds, has produced an extremely useful punching and shearing machine, which is 
 
TOOLS, TURNING. 
 
 7 1>0 
 
 capable of being worked either by manual or mechanical power. The framing consists of a single 
 casting, having a stud keyed in the thickness of the metal near its tep, for the purpose of carrying the 
 fly-wheel and driving-pinion, which are cast together. These work loose on the stud, the pinion geering 
 with a large spur-wheel keyed on the horizontal eccentric punebing-shaft. A slot is cast through the 
 centre of the frame for the reception of this shaft, suitable bearings for carrying it being placed within 
 the slot; the projecting end of the shaft is slightly eccentric, for the purpose of giving motion to the 
 vertical punching and shearing shaft. The latter consists of a heavy piece of metal, having a horizon- 
 tal slot in the centre, for the purpose of allowing a clear space for the lateral working of the eccentric 
 end of the driving-shaft. Suitable bearings are attached to the front of the frame, in which the punch- 
 ing-shaft is arranged to slide, the top of the latter being the shearing end, and the bottom carrying the 
 punch, the matrix for which is fixed in a projecting piece cast to the frame. 
 
 The machine is adapted to punch holes up to £ inch in diameter in plates § inch in thickness, at any 
 distance from the edge not exceeding 7^ inches, the frame being hollowed out to this extent to permit 
 of the entrance of the plates. The shears are capable of cutting plates § inch in thickness, and 12 inches 
 breadth, without curling the piece sheared off. 
 
 The construction of this machine is exceedingly simple, and being set in an independent framing of 
 its own, may be moved to any part of the workshop with facility. A somewhat similar machine, but 
 much more complete in its details, has been constructed by Messrs. Nasmyth and Gaskell. Here the 
 punching-slide is provided with four punches, by which means the same number of holes are punched 
 at each stroke of the machine. The punching operation is also made self-acting, by an arrangement of 
 a self-moving table for carrying the work. The plates intended to be punched are fixed in the usual 
 manner on a travelling-table, moving on wheels set to run oc i pair of triangular rails. A long notched 
 bar is attached by means of brackets to the under side of this table ; this is arranged to traverse the 
 table in the following manner : — The large driving-wheel on the eccentric shaft carries a pin fixed in 
 the side of its rim, which, once during each revolution, comes in contact with a lever connected to a 
 ratchet-catch adapted to take into the notches of the bar before mentioned ; thus each revolution of the 
 spur-wheel causes the table to advance a distance equal to the length included between each notch in 
 the bar. 
 
 In Fig. 3100 we have detailed a machine intended for the bending of wrouglit-iron plates. This ma- 
 chine, owing to the increase of iron ship-building, has latterly risen to be of great importance to the 
 engineer and ship-builder. The present machine being principally intended for the use of the ship- 
 building yard, where few plates are required to have a regular curve throughout, is not provided with 
 geering for simultaneously altering the positions of the ends of the front roller. This arrangement 
 allows of the setting of one of the ends of the roller at any position with regard to the other, so as to 
 give any required twist to the plate. 
 
 In the original application of the bending-rollers to the curving of boiler plates, none of the rollers 
 touch each other, and they are placed so that lines drawn from centre to centre form an equilateral 
 triangle, the upper central roller being made adjustable for the different curvatures required ; this 
 arrangement is, however, now entirely superseded by that depicted in Mr. Napier’s machine. 
 
 We take this occasion to acknowledge our indebtedness to the Engineer and Machinist’s Assistant, 
 published by Blackin and Son, Glasgow, for the very valuable articles on Geering, as also this one on 
 Tools. The work mentioned should be in the hands of every engineer and machinist. 
 
 TOOLS, TURNING. The process of turning is accomplished with considerably more facility, truth, 
 and expedition, than any other process requiring cutting tools, because in the most simple application 
 of the art, the guide principle is always present, namely, that of rotation. The expedition of the process 
 is due to its being uninterrupted or continuous, except as regards the progressive changes of the tool, 
 and which is slowly traversed from part to part, so as to be nearly always in action. 
 
 To choose the most simple condition, let us suppose the material to be in rotation upon a fixed axis, 
 and that a cutting tool is applied to its surface at fifty places. .Provided the tool remain quiescent at 
 one place for the period of one revolution of the material, the parts acted upon will each become one 
 circle ; because the space between the tool and the axis is for a period constant, and the revolution of 
 the material converts the distance of the tool from the centre into the radius of one circle, and the same 
 is equally true of the fifty positions. 
 
 The fifty circles will be concentric, or parallel with each other, because the same axis, extended or 
 continued as a line, remains constant, or is employed for each of them ; and therefore conceiving the 
 fifty circles to be as many parts of the outline of a vase or other object, simple or complex, it will be 
 strictly symmetrical, or equidistant from the central line at corresponding parts. 
 
 Each of the fifty circles will also become the margin of a plane at right angles to the axis, and which 
 axis being a straight line, the whole of the circles will be parallel, and therefore the top and bottom 
 of the vase will be also exactly parallel. And yet all these accurate results must inevitably occur, and 
 that without any measurement, provided the material revolve on one fixed axis, and that the tool is 
 for a short period constant or stationary at each part of the surface — conditions inseparable from the 
 turner’s art. 
 
 The principle of rotation upon a fixed axis removes the necessity for many of the steps and measure- 
 ments required to produce with accuracy the various angular solids employed in carpentry and many 
 other arts. 
 
 The turner’s box consists of two pieces, as the bottom and its four sides are resolved into one piece— 
 when of wood, by nature in the forest ; w T hen of metal, by man in the crucible. The surfaces are there- 
 fore reduced to eight, namely, the inner and outer surfaces of the bottom and lid amounting to four, and 
 the inner a-nd outer sides or margins, amounting to four also, and the revolution of the work upon one 
 axis places the eight in exact and true relation with extreme rapidity. 
 
 For example, the ends or terminal planes of the box are, from necessity, at right angles to the axis of 
 rotation, and parallel with each other. In each of these superficies the question of being in cr out oi 
 
TOOLS, TURNING. 
 
 761 
 
 winding ceases ; as, if straight, they can only be planes or cones, and which the one straight edge imme- 
 diately points out. 
 
 The principle of rotation insures circularity in the work, and perpendicularity or equality as regards 
 the central line ; it only remains, therefore, to attend to the outline or contour. The right line serves to 
 produce the cylinder, which is a common outline for a box ; and the employment of mixed, flowing, and 
 arbitrary lines, produces vases and ornaments of all kinds, the beauty of which demands attention alone 
 to one single element, or conception, namely, that of form ; and in the choice and production of which a 
 just appreciation of drawing and proportion greatly assist. 
 
 In the art of drawing, it is almost essential to the freedom of the result, that the lines should be de- 
 lineated at once, and almost without after correction ; in the art of turning, it is always desirable 
 to copy a drawing or a sketch, but having nearly attained the end, the tool may be continually re- 
 applied, partially to remove any portions which may appear redundant, until the most scrupulous eye 
 is satisfied. 
 
 The combining of the several parts of turned objects, as the separate blocks of which a column or 
 other work is composed, is greatly facilitated from the respective parallelism of the ends of the pieces 
 of which turned objects consist ; and the circular tenons and mortises, whether plain or screwed, place 
 the different pieces perpendicular and central with very little trouble. 
 
 These several and most important facilities in the art of turning, are some amongst the many reasons 
 for its having obtained so extensive and valuable an employment in the more indispensable arts of life, 
 as well as in its elegances. 
 
 The tools us.ed in turning the woods act much in the manner of the blades of the carpenter’s planes; 
 but as we have now, at all times, a circular guide in the lathe-mandrel, we do not require the stock ot 
 the plane or its rectilinear guide. Although if we conceive the sole of the plane applied as the tangent 
 to the circle, the position it would give is nearly retained, but we are no longer encumbered with the 
 stock or guide. In turning-tools for soft woods, the elevation of the tool and the angle of its edge are 
 each of them less than in ordinary planes, and in those for the hard woods both angles are greater. 
 
 Tor example, the softest woods are turned with tools the acute edges of which measure about 20 to 
 30 degrees, and are applied nearly in coincidence with the tangent, as in Fig. 3477. 
 
 These tools closely assimilate to the spokeshave, which is the plane of the lowest pitch and keenest 
 edge. On the contrary, the hardest woods may be turned with the above soft-wood tools, applied just 
 as usual ; but on the score of economy and general convenience, the edges are thickened to from 60 tc 
 80 degrees, and the face of the tool is applied almost horizontally on the lathe-rest, or as a radius to the 
 circle, as in Fig. 3478, thus agreeing with the opposite extreme of the planes, in which the cutter is 
 perpendicular and much less acute, as in the scraping and toothing planes, which are only intended to 
 6crape, and not to cut. 
 
 The hard-wood tools may be figured and employed as scrapers in turning the members of the capital 
 or the base of a column, or similar object in hard wood or ivory ; but if we try the same tools on deal, 
 ash, and other soft woods, we shall in vain attempt to produce the capital of a column, or even its cy- 
 lindrical shaft, with a thick horizontal tool as in hard wood ; for the fibres would not be cut, but forcibly 
 torn asunder, and the surface would be left coarse and ragged. 
 
 But a reference to the planes with which the joiner proceeds across the fibres of deal, will convey the 
 particulars suited to the present case ; the iron is always thin and sharp, and applied in an oblique 
 manner, so as to attack the fibre from the one end, and virtually to remove it in the direction of its 
 length. 
 
 It is proposed now to describe some of the more important of the turning tools, commencing- with 
 those employed on the soft-grained woods, but it would be both hopeless and unnecessary to attempt 
 the notice of all the varieties which are to be met with in the hands of different individuals; and only 
 so much will be here advanced as, it is hoped, may serve to explain the modifications of the general 
 principles of cutting tools to some of the more usual purposes of turning. To avoid repetition, it may 
 be observed, that in general the position of the tool for turning the cylinder, and secondly, that for the 
 flat surface or plane, will be alone described. For works of intermediate angles, whether curves or 
 flowing lines, the position of the tool slides from that for the cylinder to that for the plane, or the re- 
 verse ; and these changes will be readily made apparent when the reader gradually moves either a 
 tool, or even a rod of wood, from the one to the other of the described positions. 
 
 It may be added that most of the tools for metal are applied direct from the grindstone, the oilstone 
 being used for such tools only as are employed for the more delicate metal-works, or for the last finish 
 of those ot stronger kinds; all the tools for wood, ivory, and similar materials, are invariably sharpened 
 on the oilstone. It may be desirable to remark, in addition, that the rough exterior faces of all works 
 should be turned with narrow or pointed tools, and only a narrow portion at a time, until the sur- 
 
7G2 
 
 TOOLS, TURNING. 
 
 faces are perfectly true or concentric ; as wide flat tools applied to rough irregular surfaces, espe 
 daily of metal, would receive a vibratory, or rather an endlong motion, quite incompatible with truth 
 of work. 
 
 Turning-tools for soft wood. — Angle 20° to 30 ° — Figures generally half size. — The tools most gen- 
 erally used for turning the soft woods are the gouge and chisel, Figs. 3178 to 3479, wherein they are 
 shown of one-fourth their medium size ; they vary from one-eighth to two inches wide ; and as they are 
 never driven with the mallet, they do not require the shoulders of the carpenter’s tools, they are alsc 
 ground differently. The turning-gouge is ground externally and obliquely, so as to make the edge 
 elliptical, and it is principally the middle portion of the edge which is used ; the chisel is ground from 
 both sides, and with an oblique edge, and Figs. 3481 and 3482 represent the full thickness of the chise 1 
 and its ordinary angles, namely, about 25 to 30 degrees for soft, and 40 for hard woods. The gouges 
 and chisels wider than one inch are almost invariably fixed in long handles, measuring with the blades 
 from 15 to 24 inches ; the smaller tools have short handles, in all from 8 to 12 inches long. 
 
 Fig. 3477 shows the position of the gouge in turning the cylinder ; the bevel lies at a tangent, and tha 
 tool generally rests on the middle of the back, or with the concave side upwards, the extremity of the 
 handle is held in the right hand close to the person, and the left hand grasps the blade, with the fingers 
 folded beneath it, and in this manner the gouge is traversed along the cylinder. 
 
 For turning the flat surface the gouge is supported on its edge, that is, with the convex side towards 
 the plane of the work, and with the handle nearly horizontal, to bring the centre of the chamfered edge 
 in near coincidence with the plane ; the tool is inclined rather more than tire angle at which its chamfer 
 is ground, and it is gradually thrust from the margin to the centre of the work. 
 
 The gouge is also used for hollow works, but this application is somewhat more difficult. For the 
 internal plane, the position is almost the same as for the external, except that the blade is more inclined 
 horizontally, that it may be first applied in the centre to bore a shallow hole, after which the tool is 
 traversed across the plane by the depression of the hand which moves the tool as on a fulcrum, and it is 
 also rotated in the hand about the fourth of a circle, so that in completing the margiu or the internal 
 cylinder the tool may lie as in Fig. 3477, but with the convex instead of the concave side upwards, as 
 there shown. 
 
 In Figs. 3483 and 3484 are represented the plans, and in Figs. 3485 and 3486 the elevations of the 
 hook-tools for soft wood, which may be called internal gouges ; they differ somewhat in size and form : 
 the blades are from 6 to 12 inches long, the handles 12 to 15. They are sharpened from the point 
 around the hook as far as the dotted lines, mostly on one, sometimes on both sides, as seen by the sec- 
 
TOOLS, TURNING. 
 
 763 
 
 tions. The hook-tools follow very nearly the motion of the gouge in hollowing, the rest is placed rathe, 
 distant and oblique ; the tool is moved upon it as a fulcrum, and it is also rotated in the hand, so as al- 
 ways to place the bevel of the tool at a very small inclination to the tangent. 
 
 The finishing tools used subsequently to the gouges or hook-tools have straight edges ; the chisel, Fig 
 3487, is the most common ; its position closely resembles that of the gouge, subject to the modifications 
 called for by its rectilinear edge. If, for example, the edge of the chisel were just parallel with the axis 
 of the cylinder, it would take too wide a hold ; there would be risk of one or other corner digging into 
 the work, and the edge, from its parallelism with the fibres, would be apt to tear them out. All these 
 inconveniences are avoided by placing the edge oblique, as in Fig. 3487, in which the tool may be sup- 
 posed to be seen in plan, and proceeding from right to left, Fig. 3477 being still true for the other view; 
 the tool is turned over to proceed from left to right, and both corners of the tool are removed from the 
 work, by the obliquity of the edge. The tool may be ground square across, but it must be then held in 
 a more sloping position, which is less convenient. 
 
 • 3489. 
 
 Turning a flat surface with the chisel is much more difficult. The blade is placed quite on edge, and 
 with the chamfer in agreement with the supposed plane a b c, Fig. 3481 ; the point of the chisel then cuts 
 through the fibres, and removes a thin slice which becomes dished in creeping up a d, the bevel of the 
 tool ; it then acts something like the scoring-point of the planes, or the point of a penknife. Flat sur- 
 faces, especially those sunk beneath the surface, as the insides of boxes, are frequently smoothed with 
 an ordinary firmer chisel, which is ground and sharpened with one bevel, but rather thicker than for 
 carpentry. The edge is then burnished like the scraper, and it is applied horizontally like a hard-wood 
 tool, as in Fig. 3478, but against the face or plane surface. The wire edge then lies in the required po- 
 sition, but it must be frequently renewed. 
 
 The broad, represented in three views in Fig. 3488, endures much longer, but it requires to be held 
 downwards or underhand at about an angle of 40 to 50 degrees from the horizontal, in order to bring its 
 edge into the proper relation to the plane to be turned. Another form of the broad is also represented 
 in Fig. 34-89 ; it is a cylindrical stem, upon the end of which is screwed a triangular disk of steel, some- 
 times measuring three inches on the sides, and sharpened externally on each edge : this tool requires the 
 same position as the last. Broads of the forms b c are also used, but principally for large works the 
 plank way of the grain. Similar tools are also used for turning pewter wares. 
 
 For the insides of cylinders the side-tool, Fig. 3490, which is represented in three views, is sometimes 
 used; it is sharpened on both edges, and applied horizontally. The tool Fig. 3491, also shown in three 
 views, serves both for the sides and the bottoms of deep works, but it does not admit of being turned 
 over; and Fig. 3492 is another form of the same tool for shallower works, the cranked form of which 
 is considered to give it a better purchase. 
 
 The tools used for cutting screws in soft wood, by aid of the traversing or screw mandrel-lathe, par- 
 take of the same general characters as the others, and are represented in their relative positions ; Fig. 
 3493 is for the outside, and Fig. 3494 for the inside screw. 
 
 To conclude the notice of tools of this class, the parting-tool, Fig. 3495, has an angular notch or groove 
 on its upper surface, from which it results that when the tool is sharpened on the bevel b, the upper face 
 presents two points, which separate the fibres by a double incision. This method wastes only as much 
 wood as equals the thickness of the tool, and it leaves the work smooth and flat; whereas, when the 
 angle of the chisel is used for the same purpose several cuts are required, and the gap must present a 
 greater angle than the bevel of the tool, and which consumes both more time and wood. 
 
 The various turning-tools for soft woods which have been described are, with the exception of the 
 gouge and chisel, nearly restricted to the makers of Tunbridge- ware, toys, and common turnery ; with 
 them they are exceedingly effective, but to others somewhat difficult. The amateur turner scarcely uses 
 more than the common gouge and chisel, and even these but insufficiently, as much may be done with 
 them. It has been shown, for instance, that moulding tools cannot be used for the soft woods, but IFiey 
 are efficiently replaced by the gouge for the concave, and the chisel for the convex mouldings. 
 
7G4 
 
 TOOLS, TURNING. 
 
 A good fair practice on the soft woods would be found very greatly to facilitate the general manipur 
 lation of tools, as all those for the soft woods demand considerably more care as to their positions and 
 management than those next to be described. 
 
 3490. 
 
 3491. 
 
 Turning-tools for hard wood and ivory. — Angles 40° to 80° — Figures generally half size . — The 
 gouge is the preparatory tool for the hard as well as for the soft woods, but it is then ground less 
 acutely; the soft-wood chisel may indeed be employed upon the hardest woods, but this is seldom done, 
 because the tools with single bevels held in a horizontal position, as in Fig. 3478, are much more man- 
 ageable, and on account of the different natures of the materials they are thoroughly suitable, notwith- 
 standing that their edges are nearly as thick again as those of soft-wood tools. In general, also, the long 
 handles of the latter are replaced by shorter ones, as in Figs. 3496 and 3497, measuring with the tools 
 from 8 to 12 inches; but these give in general an abundant purchase, as from the nearly horizontal pc 
 sition of the tool, the lathe-rest or support can be placed much nearer to the work. 
 
 349G. 3497. 
 
 The hard-wood tools are often applied to a considerable extent of the work at one time, and the fin- 
 ishing processes are much facilitated by selecting instruments the most nearly in correspondence with 
 the required shapes. Rectilinear surfaces, such as cylinders, cones, and planes, whether external or 
 internal, necessarily require tools also with rectilinear edges, which are sloped in various ways as re- 
 gards their shafts ; they are made both large and small, and of proportionate degrees of strength to 
 suit works of different magnitudes. The following are some of the most useful kinds. 
 
 3498. 3499. 
 
 3300. 
 
 3585. 3580. 3587. 3583. 
 
 3589. 
 
 3590. 3591. 
 
 The right-side tool, Fig. 3498, cuts on the side and end, the dotted lines being intended to indicate the 
 undercut bevel of the edge — so named because it cuts from the right hand towards the left. The left-side 
 tool, Fig 3499, is just the reverse. The fiat-tool, Fig. 3500. cuts on both sides, and on the end likewise ; 
 
TOOLS, TURNING. 
 
 7G5 
 
 and in all three tools the angle seen in plan is less than a right angle, to allow them to be applied in 
 rectangular corners. The point-tool , Fig. 3585, is also very convenient ; and bevel-tools , Figs. 3586 and 
 3587, the halves of the former, are likewise employed ; Figs. 3588 show the general thicknesses of these 
 tools. When any of them are very narrow they are made proportionally deep to give sufficient strength, 
 the extreme case being the parting-tool, Fig. 3589, which is no longer required to be fluted, as in the 
 corresponding tool for soft wood ; but the side-tools, when used for small and deep holes, necessarily 
 require to be small in both respects, as in Fig. 3590. The inside parting-tool, Fig. 3591, is used fur 
 the removal of rings of ivory from the interior of solid works, in preference to turning the materials into 
 shavings ; it is also useful in some other undercut works. 
 
 Some of the curvilinear tools for hard wood are represented in the annexed group of figures; the 
 semicircular or round tool, Fig. 3592, is the most general, as concave mouldings cannot be made without 
 it, and it is frequently divided, as in the quarter round tools, Figs. 3593 and 3594 ; it is convenient that 
 these should be exact counterparts of the mouldings, but they may also be used for works larger than 
 themselves, bj» sweeping the tools around the curves. Convex mouldings are frequently made by rec- 
 tilinear tools, which are carried round ir a similar manner, so as to place the edge as a tangent to the 
 curve, but the bead, Fig. 3595, the astragal, Fig. 3696, or the quarter hollows, Figs. 3597 and 3598, 
 facilitate the processes, and complete the one member of the moulding at one sweep, and enable it to 
 be repeated any number of times with exact uniformity 
 
 3592. 3593. 3594. 3595. 3590. 
 
 
 
 V 
 
 ■ 
 
 
 w 
 
 
 w 
 
 
 
 
 L . — 
 
 
 
 
 
 Frequently the tools are made to include several members, as the entire base or capital of a column, 
 as in big. 3599. Similar figured tools have been applied to turning profiles of about one or one and a 
 half inches high, by employing four different tools, embracing each about a quarter of the profile, and 
 applied at four radial positions, around a ring of some three to five inches diameter; the rings are cut 
 up into radial slices, and turned flat on each face prior to being glued upon tablets. Profiles have been 
 likewise successfully and more skilfully turned, by the ordinary round, point, and fiat tools. 
 
 Figs. 3600 to 3603 represent some of the various kinds of inside tools, which are required for hol- 
 lowing vases and undercut works ; and Fig. 3604 the inside screw tool, and Fig. 3605 the outside screw 
 tool for hard wood, ivory, and the metals : these tools are made with many points, and are bevelled 
 like the rest of the group. 
 
 The hollow tools, Figs. 3595 to 3598, may be sharpened with a narrow slip of oilstone used almost 
 as a file ; but their sweeps are more accurately sharpened by conical metal grinders, supplied with 
 emery, as will be explained ; most other moulding tools, and the screw tools, are only sharpened upon 
 the face. The ends of these tools may be whetted at a slope, if it be more gradual than in Fig. 3604, 
 this however, increases the angle of the edge; but by nicking in the tools, as in Fig. 3607, by applying 
 them transversely on the grindstone, the original angle is maintained, and which is the better mode for 
 screw tools more especially. 
 
 Turning-tools for brass. — Angles 70° to 90° — Figures generally the same as the tools for hard 
 wood. — The turning-tools for brass are in general simple, and nearly restricted to round, point, flat, 
 right and left side tools, parting-tools, and screw-tools ; they closely resemble the hard-wood tools, ex- 
 cept that they are generally ground at angles of about 60° or 70°, and when sharpened it is at an 
 angle of 80° or 90° ; some few of the finishing or planishing tools are ground exactly at 90°, upon 
 metal laps or emery wheels, so as to present a cutting edge at every angle and on both sides of the 
 tools. 
 
 3G08. 3009. 3610. 
 
 It is not a little curious that the angles which are respectively suitable to brass and to iron, art 
 definitively shown to be about 90 and 60 degrees. For turning brass, a worn-out square file is occasion- 
 ally ground on all sides to deprive it of its teeth : it is used as a side-tool, and is slightly tilted, as in 
 Fig. 3608, just to give one of the edges of the prism sufficient penetration ; but applied to iron, steel, O' 
 
766 
 
 TOOLS, TURNING. 
 
 copper, it only scrapes with inconsiderable effect. A triangular file, Fig. 3609, similarly ground, cuts 
 iron with great avidity and effect, but is far less suited to brass ; it is too penetrative, and is disposed 
 to dig into the work. It appears, indeed, that each different substance requires its own particular angle, 
 from some circumstances of internal arrangement as to fibre or crystallization not easily accounted for. 
 
 A stout narrow round tool, Fig. 3592, in a long handle, serves as the gouge or roughing-out tool for 
 brass-work ; others prefer the point, Fig. 3585, with its end slightly rounded, which combines, as it were, 
 the two tools with increased strength ; a small but strong right side tool, Fig. 3582, is also used in 
 rough-turning; the graver. Figs. 3611 and 3612, although occasionally employed for brass, is more 
 proper for iron, described hereafter. 
 
 The wide finishing tools should not be resorted to under any circumstances until the work is roughed- 
 out nearly to the shape, and reduced to perfect concentricity or truth, with narrow tools which only 
 embrace a very small extent of the work. 
 
 It is the general impression that in taking the finishing cuts on brass it is impolitic, either to employ 
 wide tools, or to support them in a rigid solid manner upon the rest, as it is apt to make the work full 
 of fine lines or strife. This effect is perhaps jointly attributable to the facility of vibration which exists 
 in brass and similar alloys, to the circumstance of their being frequently used in thin pieces on the 
 score of economy, and to their being rotated more rapidly in the lathe than iron and steel, to expedite 
 the progress of the work. 
 
 When a wide flat tool is laid close down on the rest, and made to cut with equal effect throughout its 
 width, lines are very likely to appear on the metal, and which if thin, rings like a bell from the vibra- 
 tion into which it is put ; but if the one corner of the tool penetrate the work to the extent of the thick- 
 ness of the shaving, whilst the other is just flush with the surface, or out of work, the vibration is les- 
 sened, and that whether the penetrating angle or the other move in advance. 
 
 The brass-turner frequently supports the smoothing-tool upon the one edge only, and keeps the other 
 slightly elevated from the rest by the twist of the hand, which thus appears to serve as a cushion or 
 spring to annul the vibrations: Fig. 3610 shows about the greatest inclination of the tool. Some work- 
 men with the same view interpose the finger between the tool and the rest, in taking very light finish- 
 ing cuts. The general practice, however, is to give the tool a constant rotative shuffling motion upon 
 the supported edge, never allowing it to remain strictly quiet, by which the direction of the edge of the 
 tool is continually changed, so as not to meet in parallelism any former strife which may have been 
 formed, as that would tend to keep up the exciting cause, namely, the vibration of the metal. The 
 more the inclination of the tool, the greater is the disposition to turn the cylinder into small hollows. 
 
 Some workmen burnish the edges of the finishing tools for brass, like the joiners’ scraper, or the 
 firmer chisel used in soft-wood turning. On account of the greater hardness and thickness of the edge 
 of the tool, it cannot be supposed that in these cases any very sensible amount of burr or wire edge is 
 thrown up. The act appears chiefly to impart to the tool the smoothness and gloss of the burnisher, 
 and to cause it, in its turn, to burnish rather than cut the work ; the gas-fitters call it a planishing tool, 
 but such tools should never be used for accurate works until the surface is perfectly true and smooth. 
 
 The hard-wood and brass-turners avoid the continual necessity for twisting the lathe-rest in its socket 
 to various angular positions, as they mostly retain it parallel with the mandrel, and in turning hollow 
 works they support the tool upon an arm rest, ; this is a straight bar of iron, which resembles a long- 
 handled tool, but it has a rectangular stud at the end, to prevent the cutting-tool from sliding off. 
 
 The position of the arm-rest and tool, as seen in' plan, are therefore nearly that of a right angle ; the 
 former is held under the left arm, the latter in the right hand of the workman, the fore-fingers of each 
 hand being stretched out to meet near the end of the tool. This may appear a difficult method, but it 
 is in all respects exceedingly commodious, and gives considerable freedom and choice of position in 
 managing the tool, the advantage of which is particularly felt in guiding the first entry of the drill, or 
 the path of the screw-tool ; and in brass-work it likewise renders the additional service of associating 
 the tool with the elastic frame of the man. But when particular firmness and accuracy are required 
 the tool should be supported upon the solid rest as usual. 
 
 Turning-tools for iron, steel, etc. — Angles 60° to 90° — Figures generally one-sixth the full size . — 
 The triangular tool is one of the most effective in turning these metals, as was adverted to above ; 
 the triangular tool is also used by the engravers and others for scraping the surfaces of the metals, 
 and it is then applied nearly perpendicular, or as a penknife in erasing ; but when the triangular tool is 
 placed nearly as a tangent against the inner or outer edge of a ring or cylinder, as in Fig. 3609, it 
 seems almost to devour the metal, and instead of scratching, it brings off coarse long shavings. In 
 turning the flat sides of the ring, the face of the tool is placed almost in agreement with the plane to 
 be turned. 
 
 The graver, which is also an exceedingly general tool, is a square bar of steel ground off at the end, 
 diagonally and obliquely, generally at an angle of from 30 to 50 degrees. The parts principally used 
 are the two last portions of the edge close to the point, and to strengthen the end of the tool a minute 
 facet is sometimes ground off, nearly at right angles to the broad chamfer, or principal face. 
 
 The proper position of the tool in turning a cylinder, will be most readily pointed out by laying the 
 chamfer of the tool in exact contact with the flat end of such cylinder ; it will be then found that one 
 of the lateral angles of the tool will touch the rest, and the obliquity in the shaft of the tool would be 
 the angle, at which the graver is ground, instead of which it is held square and slightly elevated above 
 the horizontal position, as shown in Fig. 3611. The graver is rotated upon the supporting angle, which 
 sticks into the rest, much the same as the edge of the triangular tool ; in fact, the two tools, although 
 different in form, remove the shaving in a very similar manner. 
 
 In using the graver and other tools for the metals, it is the aim to avoid exposing the eDd of the tool 
 to the rough gritty surface of the material. This is done by cleaning the surface, especially the extreme 
 edge, with an old file, and beginning at that edge, the work is at one sweep reduced nearly to its re- 
 quired diameter by a wide thin cut, which may be compared with a chamfer, or a conical fillet, con 
 
TOOLS, TURNING. 
 
 767 
 
 necting the rough external surface with the smooth reduced cylinder. Therefore after the first entry, 
 the point of the tool is buried in the clean metal below the crust, and works laterally, which is indeed 
 the general path of pointed tools for metal. 
 
 When the graver is used in the turn-bench with intermittent motion, as for the pivots of watches, the 
 axes for sextants, and other delicate works, it is applied overhand, or inverted, as in Fig. 3612 ; but it 
 is then necessary to withdraw the tool during each back stroke of the bow, to avoid the destruction of 
 the acute point, and which alone is used. The graver, when thus applied in lathes with continuous 
 motion, is only moved on the rest as on a fulcrum, and in the plane in which it lies, rather as a test ol 
 work done, than as an active instrument. 
 
 The edge of the graver is afterwards used for smoothing the stronger kinds of work ; it is then neces- 
 sary to incline the tool horizontally, to near the angle at which it is ground, in order to bring the sloping 
 edge parallel with the surface. But the smoothing is better done by a thick narrow flat tool, ground 
 at about sixty degrees, the handle of which is raised slightly above the horizontal, as in Fig. 3613, in 
 order that its edge may approach the tangential position ; here also the tool is rotated on one edge, 
 after the manner of the brass tools or the graver. 
 
 For many slight purposes requiring rather delicacy than strength, as in finishing the rounded edge 
 of a washer, the flat tool is inverted or placed bevel upwards, as in Fig. 3614 ; the lower side, then be- 
 comes the tangent, and the edge the axis of rotation of the tool, the same as in turning convex mould- 
 ings with the soft-wood chisel. Indeed, many analogies may be traced between the tools respectively 
 used for soft woods and iron, except that the latter are ground at about twice the angle to meet the 
 increased resistance of the hard metal, and the tools are mostly sustained by the direct support of the 
 rest, instead of resting in great measure against the hands of the individual. 
 
 3016 . 
 
 For instance, the lieel-tool, which is used for rough-turning the metals, is represented of the full size 
 in the side view, Fig. 3615, and the front view, Fig. 3616, and also on a, smaller scale in Figs. 3617 and 
 3618. The dotted lines a, Fig. 3617, denote the relative position of the fluted gouge, and although the 
 heel or hook-tool occupies nearly the same spot, its edge is of double the thickness, aud the entire re- 
 sistance of the cut is sustained by the heel of the tool, which is poised upon the flat horizontal surface 
 of the rest ; the shaft of the tool is bent nearly at right angles, that it may be held either above or be- 
 low the shoulder of the workman, as preferred. Some variation is made in the form and size of the 
 heel-tools, and they are occasionally pointed instead of round upon the cutting-edge. 
 
 The heel-tool is slightly rotated upon its heel in its course along the work, so that, as seen at h, it? 
 
7G8 
 
 TOOLS, TURNING. 
 
 edge travels in short arcs, and when its position becomes too inclined, a fresh footing is taken ; on this 
 account the straight handle, employed in ordinary tools, is exchanged for the transverse handle repre- 
 sented. In the best form of heel-tools the square shaft lies in a groove in the long handle, and is fixed 
 by an eye-bolt and nut, passing through the transverse handle, as seen in the section, Fig. 3618. Not- 
 withstanding the great difference the materials upon which tire gouge and heel-tool are employed, their 
 management is equally easy, as in the latter the rest sustains the great pressure, leaving the guidance 
 alone to the individual. 
 
 Fig. 3619 represents another kind of liook-tool for iron, which is curiously, like the tools Figs. 3483 to 
 3484, p. 707, used for soft wood, the common differences being here also observable, namely, the in- 
 creased strength of edge, and that the one edge is placed upon the rest to secure a firm footing or hold. 
 
 Nail-head tools are made much on the same principle : one of these, Fig. 3620, is like a cylinder, ter- 
 minating in a chamfered overhanging disk, to be rolled along so as to follow the course of the work, but 
 it is rather a theoretical than practical instrument. When, however, the tool is made of a square or 
 rectangular bar, and with two edges, as at Fig. 3621, it is excellent, and its flat termination greatly 
 assists in imparting the rectilinear form to the work. Occasionally the bar is simply bent up at the 
 end to present only one edge, as in Fig. 3622 ; it is then necessary the curved part should be jagged as 
 a file to cause it to dig into the rest like the others of its class, and which present some analogy to the 
 soft-wood tools, Figs. 3488 and 3489, p. 707. 
 
 The cranked, or hanging tools, Fig. 3623, are made to embrace the rest, by which they are prevented 
 from sliding away, without the necessity for the points and edges of the heel-tools ; the escape of the 
 cranked-tool sideways is prevented by the pin inserted in one of the several holes of the rest. The 
 direct penetration is caused by the depression of the hand ; the sideway motion by rotating the tool by 
 its transverse handle, which is frequently a hand-vice temporarily screwed upon the shaft. To save 
 the trouble of continually shifting the lathe-rest, an iron wedge (not represented) is generally intro- 
 duced at a, between the rest and the back of the tool ; when the wedge is advanced at intervals it sets 
 the tool deeper into the work, when it is withdrawn it allows more room for the removal of the tool. 
 
 Fig. 3624 represents a tool of nearly similar kind ; the stock is of iron, and it carries a piece of steel, 
 about three or four inches long, and one inch square, which is forged hollow on the faces by means of 
 the fuller, to leave less to be ground away on the stone. The rectilinear edges of this tool are used 
 for smoothing iron rollers, iron ordnance, and other works turned by hand, and to preserve the edge of 
 the tool, thin spills of hard wood are sometimes placed between the cutter and the bar. Under favora- 
 ble arrangements these tools also are managed with great facility ; indeed, it occasionally happens that 
 the weight of the handle just supplies the necessary pressure to advance the tool, so that they will rest 
 in proper action without being touched by the hand ; a tolerable proof of the trifling muscular effort 
 occasionally required, when the tools are judiciously moulded and well applied. 
 
 These hand-tools, and various others of the same kinds, although formerly much used by the mill 
 wrights, are now in a great measure replaced by the fixed tools applied in the sliding-rest. 
 
 Fixed or machine tools for turning and planing. — Angles as in the hand-tools — Figures generally 
 one-fourth to one-eighth the full size . — The performance of fixed tools is, in general, much more effective 
 than that of hand-tools ; as the rigid guides and slides now employed do not suffer the muscular fatigue 
 of the man, nor do they experience those fluctuations of position to which his hand is liable. There- 
 fore, as the tool pursues one constant undeviating course, the corresponding results are obtained both 
 more economically and more accurately by the intervention of the guide-principle, or the slide-rest, from 
 which we derive the side-lathe, and thence the planing machine, and many other most invaluable tools. 
 
 The cutting edges of machine-tools mostly follow the same circumstances as those of hand-tools, but 
 additional care is required in forming them upon principle ; because the shafts of the fixed tools are 
 generally placed, with little power of deviation, either at right angles to, or parallel with, the surfaces 
 to be wrought ; the tools are then held in the iron grasp of screws and clamps, in mortises, staples, and 
 grooves. The tools do not, therefore, admit of the same accommodation of position, to compensate for 
 erroneous construction, or subsequent deterioration from wear, as when they are held in the hand of the 
 workman, and directed by his judgment. 
 
 It must also be additionally borne in mind that, however ponderous, elaborate, or costly the machine 
 may be, its effectiveness entirely depends upon the proper adaptation and endurance of the cutting-tool, 
 through the agency of which it produces its results. 
 
 The usual position of the fixed turning-tools is the horizontal line, as at a, Fig. 3625 ; and unless the 
 tools always lie on the radius, (or any other predetermined line.) various interferences occur. For in- 
 stance, the tool proceeding in either of the lines b or c, could not reach the centre of the work, and a 
 portion w’ould then escape being wrought; the curvature of the circle at b would sacrifice the proper 
 angle, and expose the tool to fracture from the obliquity of the strain ; and at c, the edge would be 
 altogether out of contact, and the tool could only rub anil not cut. These evils increase with the dim 
 inution of the circle ; and although the diagram is greatly exaggerated for illustration, the want of 
 centrality is in truth an evil of such magnitude that various contrivances are resorted to, by which either 
 the entire slide-rest, or the cutter alone, may be exactly adjusted for height of centre. 
 
TOOLS, TURNING. 
 
 769 
 
 The planing tools for metals are in general fixed vertically, and the path of the work being, in the 
 majority of planing-machines, rectilinear and horizontal, the tool may be placed at d, e, or /, indiffer- 
 ently, there being no interference from curvature as in turning. 
 
 In those modifications of the planing-machine in which, as in Brunei’s mortising-engine, the cutter 
 travels perpendicularly, and is also fixed perpendicularly, as in the key-groove or slotting-engines, and 
 the paring-engines, the general form of the tool/, or that of a strong paring chisel, is retained, but the 
 blade is slightly inclined in its length as at j, Fig. 3626, to avoid touching the surface to be wrought 
 expect with its cutting edge, and the length of the tool supplies a little elasticity to relieve the friction 
 of the back stroke. 
 
 Although all the various forms of hand-turning tools are more or less employed as fixed tools, still 
 the greater part of the work is done with the point-tool, (such as g, in the plan Fig. 3626,) the angle of 
 which should be slightly rounded ; but for working into an angle, the point of the tool is thrown off as 
 at h, so that its shaft may avoid either side of the angle, and it is then called a side-tool. For internal 
 works, and in small apertures especially, the abrupt curvature requires particular attention to the cen- 
 tral position of the tool i, and a frequent sacrifice of the most proper form of the chamfer or edge. We 
 will now describe a few of the slide-rest tools in the previous order, namely, those for soft wood, for 
 hard wood, for brass, and for iron. 
 
 The fixed tools for soft wood require the same acute edges and nearly tangential positions as those 
 used by hand ; and if these conditions exist, it is quite immaterial whether the tool touch the work 
 above or below the centre ; but the central line, or a, Fig. 3625, is the most usual. The soft-wood 
 gouge, or hook-tool, is successfully imitated by making an oblique hole in the end of a bar of steel, as 
 seen in two views in Fig. 362/ but it is not very lasting ; or a bar of steel may be bent to the form ot 
 Fig. 8628, and sharpened internally, either rounded to serve as a gouge, or straight and inclined as a 
 chisel, but neither of these tools admits in itself of adjustment for centre. 
 
 The difficulty of centre is combated by the use of a tool exactly like a common gouge or chisel, but 
 only an inch or two long, and with a cylindrical stem also an inch or two long, by which it may be re- 
 tained at any height, in the end of a bar of iron, having a nearly perpendicular hole and an appropriate 
 side-screw for fixing the tool ; this construction is abundantly strong for wood. 
 
 The fixed tools for hard loood and ivory follow the several forms of the hand-tools, Figs. 3498 to 3605, 
 except in having parallel stems ; they are always placed horizontally, and are treated in all respects 
 just as before. Care should be taken, however, that the end of the tool is its widest part ; in’ order that, 
 if it be sent in below the surface of the work, as in cutting a groove, it may clear well and not rub 
 against the sides. 
 
 In sharpening the tools intended for hard wood and ivory, the oil-stone should be applied principally 
 at the end, or on the chamfer of the tool, as this will not reduce the height of centre, which it. is always 
 important to retain. If, however, the tools should eventually become chamfered off, after the manner 
 of Fig, 3606, they may be annealed, and thrown up to place the chamfered part in the line of the gene- 
 ral face ; they are then rehardened, and ground up as at first. But as most of the slide-rests for wood- 
 turning are fitted into pedestals by means of a cylindrical stem with a vertical screw adjustment, the 
 tools may be at all times accurately centered when particular care is required ; and this provision is of 
 still greater importance, with the several revolving cutters applied to the slide-rest, which will be here- 
 after adverted to. 
 
 The fixed tools for brass and for iron, whether used in the lathe or the planing-machine, will be con 
 Von. II.— 49 
 
770 
 
 TOOLS, TURNING. 
 
 sidered in one group ; the principal difference is, that the tools for brass present an angle of nearly 90 
 degrees, the tools for iron an angle of 60, to the superficies to be wrought. Indeed, the angles or edges 
 of the cube may be considered as the generic forms of the tools for brass, and the angles or edges of 
 the tetrahedron, as the generic forms of the tools for iron ; that is, supposing the edges or planes of 
 these solids to be laid almost in contact with the line of motion or of the cut, in order that they may 
 fulfil the constant conditions of the paring tools. 
 
 The fixed tools for brass and similar alloys resemble, as in hand- turning, the more simple of the hard 
 wood tools, except that they are sharpened a trifle thicker on the edge ; they are, however, nearly re' 
 stricted to the point-tool, the narrow round tool, and to the side-tool, which is represented at j, Fig. 3626 
 It is ground so that the two cutting edges meet at an angle not exceeding about 80 degrees, that in 
 proceeding into rectangular corners it may clear each face by about five degrees, and it will then cut 
 in either direction, so as to proceed into the angle upon the cylindrical line, and to leave it upon the 
 plane surface, or it may be applied just in the reverse manner without intermission. 
 
 When the tool is used for rough work the corner is slightly rounded, but in finishing it is usually 
 quite sharp ; and as it differs only some ten degrees from the solid angle of a cube, it is abundantly 
 strong. If the tools acted upon a considerable extent or width of the brass, they would be liable to be 
 set in vibration ; but as the paths of the cutters are determined by the guide principle employed, the 
 point fulfils all that can be desired. 
 
 The fixed tools for iron present more difficulties than the generality of the foregoing kinds; first, the 
 edges of the tools are thinner and more interfered with in the act of grinding, as the vertical height of 
 the cutting edge is reduced when either face of the wedge is ground ; and secondly, they are exposed 
 to far more severe strains from the greater hardness of the material, and the less sparing manner in 
 which it is reduced or wrought, owing to its smaller price and other circumstances ; and therefore, the 
 most proper and economic forms of the tools for iron are highly deserving of attention. 
 
 The fracture of a tool when it is overloaded commonly points out the line of greatest resistance or 
 strain. Tire tool, Fig. 3629, although apparently keen, is very weak, and it is besides disposed to pur- 
 sue the line at which its wedge-formed extremity meets the work, or to penetrate at an angle of some 
 30 degrees. Fig. 3629 would probably break through a line drawn nearly parallel with the face a b of 
 the work under formation ; that portion should therefore be made very nearly parallel with a b, the line 
 of resistance, in order to impart to the tool the strength of the entire section of the steel ; so that should 
 it now break it will have a much longer line of fracture. The tool thus altered is very proper for brass, 
 an alloy upon which acute tools cannot be favorably employed. 
 
 But with the obtuse edge of Fig. 3630 other metals will be only removed with considerable labor, as 
 it must be remembered the tool is a wedge, and must insinuate itself as such amongst the fibres of the 
 material. To give the strengthened tool the proper 
 degree of penetration, the upper face is next sloped, 
 as in Fig. 3631, to that angle in which the minimum 
 of friction and the maximum of durability of the edge 
 most nearly meet ; and which, for iron, is shown to 
 be about 60 degrees, as in the triangular tool, Fig. 
 
 3609. The three planes of pointed tools for iron, 
 meeting at 60 degrees, constitute the angle of the te- 
 trahedron, or the solid wdth four equilateral planes, 
 like a triangular pyramid, the base and sides of which are. exactly alike. 
 
 But the form of Fig. 3631 would be soon lost in the act of grinding; therefore, to conclude, the tool 
 is made in the bent form of Fig. 3632, in which the angles of Fig. 3631 are retained, and the tool may 
 be many times ground without departing from its most proper form. This is in effect extending the 
 angle of the tetrahedron into the triangular prism ground off obliquely, or rathfer, as seen in the front 
 view, Fig. 3633, into a prism of five sides, the front angle of which varies from 60 degrees to 120 de- 
 grees, and is slightly rounded, the latter being most suitable for rough work ; sometimes the front of the 
 prism is half-round, at other times quite flat: these forms are shown in Fig. 3639. 
 
 The extremities of Figs. 3631 and 3632 approach very closely to the form of the graver used for en- 
 graving on steel and copper-plates, than which no instrument works more perfectly. The slender graver, 
 whether square or lozenge, is slightly bent, and has a flattened handle, so that the ridge behind the 
 point may lie so nearly parallel with, and so completely buried in, the line or groove under formation, 
 as to be prevented or checked by the surface contact from digging into the work. This is another con- 
 firmation of the fact that the fine of penetration is that of the lower face of the cutter or wedge, or that 
 touching the work. 
 
 In adopting the crank-formed tools, Fig. 3632, the principle must not be carried into excess, as it 
 must be remembered we can never expunge elasticity from our materials, whether viewed in relation 
 to the machine, the tool, or the work. 
 
 The tool should be always grasped as near the end as practicable, therefore the hook or crank should 
 occupy but little length ; as the distance from the supposed line of the fixing-screw c to the edge of the 
 tool being doubled, the flexure of the instrument will be four-fold ; when trebled, nine-fold ; in fact, as 
 the square. And also as the flexure may be supposed to occur from near the centre of the bar, (that 
 .s, neglecting the crook,) the point of the tool should not extend beyond the central line o ; otherwise 
 when the tool bends, its point would dig still deeper into the work from its rotation on the intersection 
 of c and o; the point situated behind the central line would spring away from, or out of, instead of into 
 the work. To extend the wear of the cranked tools they are commonly forged so that the point is nearly 
 level witli the upper surface of the shaft, as in Fig. 3638 ; they then admit of being many times ground 
 before they reach the central line, and they are ultimately ground (always at the end of the prism and 
 obliquely) until the hook is entirely lost. This avoids such frequent recurrence to the forge lire, but i* 
 is a departure from the right principle to allow the point to extend beyond the centre line o. 
 
 3629. 3630. 3631. 3632. 3633. 
 
 - | 
 
TOOLS, TURNING. 
 
 77] 
 
 The works of the lathe and planing-machine frequently present angles or rebates, chamfers, grooves' 
 and under-cut lines, which require that the tool should be bent about in various ways, in order that 
 their edges may retain as nearly as possible the same relations to all these surfaces, as the ordinary 
 surfacing tools, Figs. 8631 and 3632, have to the plane a b. For instance, the shaft of the tool Fig 
 3631, when bent at about the angle of 46 degrees, becomes a side cutting and facing tool, as shown in 
 plan in Fig. 3634, in elevation in Fig. 3635, and in perspective in Fig. 3636 ; and in like manner the 
 cranked tool, Fig. 3632, when also bent as in Fig. 3634, becomes Fig. 3637, and is also adapted to work- 
 ing into angular corners upon either face. 
 
 / 3634 . 3636 . 
 
 Mr. Nasmyth’s tool-gage, shown in elevation in Fig. 3638, and in plan in Fig. 3639, entirely removes 
 the uncertainty of the angles given to these irregular bent tools ; for instance, when the shaft of the tool 
 is laid upon the flat surface and applied to the iron cone c, whose side measures about 3° with the per- 
 pendicular, it serves with equal truth for s, the tool for surfaces; p and/, the side-cutting tools, used 
 also for perpendicular cuts and fillets ; and u for under-cut works. 
 
 3638 . 
 
 3639 . 
 
 "1 
 
 In applying tools to lathe works of small diameters, it is necessary to be very exact, and not to place 
 them above the centre, or they immediately rub ; and as this soon occurs with tools having so small an 
 angle, it appears desirable to make the cone-gage for small lathe works of about twice the given angle, 
 and to mark upon the cone a circle exactly indicative of the height of centre ; the tool can be then 
 packed up to the centre line, with one or two .dips of sheet-iron, to be afterwards placed beneath the 
 tool when it is fixed in the lathe-rest. In small hollow works, the most lasting or the crank-formed 
 tools are entirely inapplicable ; indeed, so much attention is required to prevent the tool from rubbing 
 against the interior surfaces, that the ordinary angles cannot be employed, and the cone-gage ceases to 
 be useful, but in every other case it should be constantly resorted to ; the additional thickness a is re- 
 quired to make it applicable to the crank-formed tools. 
 
 3640 . 3641 . 
 
 I 
 
 3643 . 
 
 3642 . 
 
 Fig. 3640 represents a cutter introduced in the block machinery at Portsmouth, England, to lessen 
 the difficulty of making and restoring the tools for turning the wrought-iron pins for the sheaves ; it 
 consists of a cylindrical wire which, from being ground off obliquely, presents an elliptical edge ; the 
 tool is fixed in a stock of iron, terminating in an oblique hole, with a binding-screw. The tool, when 
 used for iron, in the “pin turning lathes,” was made solid; when used for -turning the surfaces of the 
 wooden shells, in the “shaping engine,” it was pierced with a central hole ; the latter could only facili 
 
TOOLS, TURNING. 
 
 1 1 . 
 
 tate the process of sharpening without altering the character of the edge, which continued under tht 
 same circumstances as when solid. 
 
 About sixteen years back the author made for his own use a tool such as Fig. 3640, but found that 
 with rough usage the cutter was shivered away, on account of its breadth, and he was soon led to sub- 
 stitute for the solid cylinder a triangular cutter, the final edge of which was slightly rounded, and placed 
 more nearly perpendicular, in a split socket with a side screw, as in Fig. 3641. The strength of the 
 edge was greatly increased, and it became, in fact, an exact copy of the most favorable kind of tool for 
 the lathe or planing-machine, retaining the advantage that the original form could be always kept, 
 with the smallest expenditure of time, and without continually reforging the blade, to the manifest de- 
 terioration of the steel from passing so frequently through the fire ; it being only requisite to grind its 
 extremity like a common graver, and to place it so much higher in the stock as to keep the edge at all 
 times true to the centre. 
 
 A right and a left hand side-tool for angles, the former seen in Figs. 3642 and 3643, were also made; 
 the blade and set-screw were placed at about 45°, and at a sufficient vertical angle to clear both the 
 inside of a cylinder of three inches diameter and also to face the bottom or surface. These side-tools 
 answered very well for cast-iron ; but Fig. 3641, the ordinary surfacing tool, is excellent for all purposes, 
 and has been employed in many extensive establishments. 
 
 The prismatic cutters admit of the usual variations of shape : sometimes two binding screws are used, 
 and occasionally a tail screw, to receive the direct strain of the cut. When the blades are only used 
 for cutting in the one direction, say from right to left, they may, with advantage, be ground with a 
 double inclination ; for as all these pointed tools work laterally, the true inclination of some 60° to the 
 narrow facet or fillet operated upon is then more strictly attained. 
 
 Considerable economy results from this and several other applications, in which the cutter and its 
 shaft are distinct parts. The small blades of steel admit of being formed with considerable ease and 
 accuracy, and of being hardened in the most perfect manner. And when the cutters are fixed in strong 
 bars or shafts of iron, they receive any required degree of strength, and the one shaft or carriage will 
 serve for any successive number of blades. 
 
 'The blades are sometimes made flat, or convex in the front, and ground much thinner, to servo for 
 soft wood ; the tools for hard wood and ivory, being more easily ground, do not call for this application 
 of detached blades. 
 
 In turning heavy works to their respective forms, a slow motion and strong pointed tools are em- 
 ployed ; but in finishing these works with a quicker rate of motion, there is risk of putting the lathe in 
 a slight tremor, more particularly from the small periodic shocks of the toothed wheels, which in light 
 finishing cuts are no longer kept in close bearing as in stronger cuts. 
 
 Under these circumstances, were the tools rigid and penetrative, each vibration would produce a line 
 or scratch upon the surface, but the finishing or hanging tools, Figs. 8644 and 3645, called also spring- 
 ing tools, which are made of various curves and degrees of strength, yield to these small accidental mo- 
 tions. The first resembles in its angles the rest of the tools used for brass, the second those for iron ; 
 their edges are rectdinear, and sometimes an inch wide. The width and elasticity of these finishing tools 
 prevent their acting otherwise than as scrapers for removing the slight superficial roughness without 
 detracting from the accuracy of form previously given. In a somewhat similar manner the broad hand 
 flat tool, rendered elastic by its partial support, as in Fig. 3610, is frequently used for smoothing brass 
 works, and others turned with the slide-rest. 
 
 Figs. 3646 and 3641 represent a very excellent finishing tool, introduced by Mr. Clement, for planing 
 cast and wrought iron and steel ; it resembles the cranked tools generally, but is slighter ; it is made 
 smooth and flat upon the extremity, or rather in a very minute degree rounded. This tool is sharpened 
 very keenly upon the oil-stone, and is used for extremely thin cuts, generally one-quarter of an inch 
 wide, and when the corners just escape touching the work is left beautifully smooth; the edge should 
 on no account stand in advance of the centre line. But to avoid the chatters so liable to occur in brass 
 works, Mr. Clement prefers for that material the elastic planing-tool, Figs. 3648 and 3649 ; its edge is 
 situated considerably behind the centre. 
 
 In concluding the notice of the turning tools it may be necessary to add a few words on those used 
 for lead, tin, zinc, copper, and their ordinary alloys. The softest of these metals, such as lead, tin, and 
 soft pewter, may be turned with the ordinary tools for soft wood ; but for the harder metals, such as 
 
TOOL, RADIAL DRILLING. 
 
 773 
 
 zinc, and hard alloys containing much antimony, the tools resemble those used for the hard woods, and 
 they are mostly employed dry. 
 
 Copper, which is much harder and tougher, is turned with tools similar to those for wrought-iron, but 
 in general they are sharpened a little more keenly, and water is allowed to drop upon the work to lessen 
 the risk of dragging or tearing up the face of the copper, a metal that neither admits of being turned or 
 filed with the ordinary facility of most others. Silver and gold, having the tenacious character of cop 
 per, require similar turning tools, and they are generally lubricated with milk. 
 
 In the above, and nearly all the metals except iron and those of equal or superior hardness, there 
 seems a disposition to adhere, when by accident the recently removed shaving gets forcibly pressed 
 against a recently exposed surface, (the metals at the time being chemically clean ;) this disposition to 
 unite is nearly prevented when water or other fluid is used. 
 
 Water is occasionally resorted to in turning wrought-iron and steel ; this causes the work to be left 
 somewhat smoother, but it is not generally used, except in heavy work, as it is apt to rust the machin- 
 ery ; oil fulfils the same end, but it is too expensive for general purposes. 
 
 Cast-iron, having a crystalline structure, the shavings soon break without causing so much friction as 
 the hard ductile metals ; cast-iron is therefore always worked dry, even when the acute edges of 60 
 degrees are thickened to those of 80 or 90, either from necessity, as in some of the small boring tools, 
 or from choice on the score of durability, as in the largest boring tools and others. Brass and gun metal 
 are also worked dry, although the turning tools are nearly rectangular, as the copper becomes so far 
 modified by the zinc or tin, that the alloys, although much less crystalline than cast-iron, and less duc- 
 tile than copper, yield to the turning tools very cleanly without water. 
 
 But when tools with rectangular edges are used for wrought-iron and steel, on account of the greater 
 cohesion of these materials, they must be lubricated with oil, greese, soap and water, or other matter, 
 to prevent the metals from being torn. And the screw-cutting tools, many of which present much sur- 
 face friction, and also rectangular or still more obtuse edges, almost invariably require oil or other unc- 
 tuous fluids for all the metals. 
 
 In the practice of metal turning the diamond point a b, Big. 2845, is occasionally used in turning 
 hardened steel and other substances ; i f, Fig. 2845, are constantly used in engraving by machinery, 
 and in graduating mathematical instruments. 
 
 TOOL, RADIAL DRILLIISU — By Messrs. Whitworth & Co., Manchester. This is an entirely 
 different arrangement of drilling machine from those before described. It embodies the elegant feeding 
 apparatus introduced by the same makers, and described in the account already given of their vertical 
 drilling machine, p. 387 ; but in that form of the machine the drilling spindle does not admit of any lat- 
 eral motion ; it is strictly confined to the same vertical position, and in that can rise and fall at the wil.' 
 
774 
 
 TOOL, RADIAL DRILLING. 
 
 of the operator ; but in this the drill-spindle has not only the same vertical and revolving motions as ir. 
 that form of the machine, but admits also of a lateral motion whereby it can be brought over the work 
 into any required position within the limits of the radial arm D, on which the whole drilling apparatus 
 is carried. 
 
 The arrangement consists of a strong upright framing A A, Fig. 3650, with a sole by which it can be 
 bolted to a stone foundation. To this is attached a vertical sliding bracket B B B, attached by dove- 
 tailed guides. This bracket is raised and lowered at pleasure, according to the height required for the 
 work, by means of a handle which fits on the end of the tangent-screw L ; this screw works into the 
 tangent- wheel K, on the spindle of which is a small pinion which geers with a rack on the back of the 
 bracket B B. The bracket is secured, when raised to its proper position, by the pinching-screw w, on 
 the outer end of which a handle is fixed. 
 
 C C is the sole of the radial arm D D. It is supported in bearings at its extremities in the vertical 
 slide B B, and by this means can swing through an arc of 180 degrees. On this arm D D is carried 
 movable slide, to which all the drilling apparatus is attached. 
 
 3IS5J. 
 
 E is the pulley-cone by which motion is communicated to the machine. On the spindle of this cone 
 is keyed the bevel-wheeiy, which geers with the similar wheel marked e on the vertical spindle g. This 
 spindle is provided with a sunk-feather to allow it to slide through the eye of the wheel e when the 
 bracket is moved vertically. On the upper end of the spindle g is keyed the bevel-wheel h, which 
 works into another similar wheel on the end of the horizontal and hollow shaft G, which has its bearing 
 in the boss F. This hollow shaft G has a groove-cut inside of it to receive a feather inserted into the 
 spindle k, which passes into it, and with which it must of necessity turn by virtue of the connecting 
 feather or key projecting from the surface of k. The other end of the spindle k has its extreme bear- 
 ings in the slide, and has the bevel-wheel o keyed upon it ; this wheel geers with that marked n on the 
 drill-spindle. It is therefore clear that motion being communicated to the driving pulley-cone E, it will 
 be transferred to the bevel-pair f and e, then to the similar bevel-pair at li, and from that point through 
 g and k to the bevel-pair o and n, the last of which is placed on the drill-spindle l with a sliding feather 
 or key, as before explained. 
 
 We have described the wheel which geers with that marked h, as being directly keyed on the hollow 
 
TOOL, PORTABLE DRILLING. 
 
 775 
 
 piece G- ; this, however, is not the case : the wheel is keyed on an independent short spindle of its own, 
 which enters G- in F, and connects itself also by a sunk key, so that the piece G is nothing more than a 
 coupling for this spindle with that marked k, and can moreover be slid considerably further into the 
 boss F than is represented in the drawing, Fig. 3652. 
 
 The slide is moved along the radial arm D by a crank-handle placed on the squared end of the screw 
 v v, which passes through a nut fixed on the back of the slide in the usual manner. 
 
 The slide moves along the arm in dovetail guides, as shown in the front view, Fig. 3653 ; on the 
 upper side are the adjusting piece c and setting-screws d. 
 
 As already stated, the feeding apparatus, and in fact all the drilling tackle, is identical in arrange- 
 ment with that described on p. 387 : pp are the friction-pulleys on the same axes as the screw-wheels 
 which geer with the screwed part r of the drill-spindle, q q are the friction-clips upon the pulleys p p, 
 and s is the screwed rod by which the clips are brought into action. 
 
 For some special purposes the radial drill affords great convenience, hut where much accuracy is re- 
 quired it cannot be so well depended upon as the ordinary form, as it rarely possesses the requisite 
 degree of rigidity. 
 
 It may be here observed, that the merit of first introducing this description of drilling machine is due 
 to Messrs. Benjamin Hick & Son, of Bolton. 
 
 3654. 3653. 3655. 
 
 TOOL, PORTABLE DRILLING — By Nasmyth, Gaskell <fe Co., Manchester, big. 3652 is a side 
 elevation of the machine; Fig. 3653, a front view. 
 
 Fig. 3654 is a partial section through the axis of the drill-spindle. 
 
 Fig. 3655, a cross-section above the table N, showing the form of the frame A. A. 
 
 This frame is formed of one casting, and is bolted to a large sole-plate, which serves as a foundation 
 without other fixing. 
 
 B B, the drill-spindle, passes through a long tube marked C C, and which serves as a guide to the 
 spindle, in ascending and descending. The spindle is attached by a sunk-featlier to the interior of the 
 tube, so that the spindle can slide in it vertically, but cannot turn round within it. 
 
 D D, the two fixed brackets in which are the bearings of the guide-table C C, the plan of which is 
 shown separately by Fig. 3658. 
 
 E, a set of driving cone-pulleys corresponding to the lower set of cone-pulleys F. On these two set; 
 
TORSION. 
 
 (76 
 
 of pulleys is placed the belt, -which directly gives motion to the drill-spindle by means of the bevel-pair 
 a and b, of which the wheel marked a is keyed on the guide-tube 0 C of the drill-spindle, and tha* 
 marked b is fast on the rod of the same spindle on which are the cone-pulleys E. 
 
 G and H, a pair of pulleys, one fast and the other loose, by which the machine is driven. They are 
 upon the same spindle as the lower cone-pulleys F, by w'hicli the motion is conveyed through a belt to 
 the pulley E. 
 
 I, a link connecting the foot-lever J with the weighted lever L, one end of which enters a recess d of 
 the sliding bracket h h, the sole of which is guided in dovetail grooves, formed by the pieces bb bb, seen 
 in Fig. 3653. From this arrangement it is easy to perceive that when the foot is pressed upon the foot- 
 board at J, the link I will cause the weighted end of the lever L to ascend, and the other to descend ; 
 and at the same time the sliding bracket, into which is fitted the top of the drill-spindle. 
 
 The manner of attaching the drill-spindle to the sliding bracket is rendered obvious by Fig. 3654 : 
 the top is formed with a rutf upon it, which is kept in the screwed recess formed in c to receive it, by 
 the hollow screw which bears against the under side of the ruff. The spindle is at the same time met 
 above by a screwed steel pin. The end of this pin sustains the downward pressure when the foot is 
 placed on the treddle J. 
 
 M is the bracket of the table 1ST. The table is simply a plank of wood resting upon the top plate of 
 the bracket. 
 
 As the travel of the drill-spindle is very limited, the table-bracket can be raised and lowered at pleas- 
 ure, through the required range, by means of the screw S. Its sole is guided vertically by grooves k k 
 in the frame ; this has also grooves formed in it to receive the heads of the setting-bolts m m, the nuts of 
 which, being screwed tight, keep the bracket in its place. The bolt-heads are entered through the open- 
 ings n, and slide down the grooves 1 1 ; the arrangement of the table-screw S, with the hand-wheel for 
 working it, also its socket with the treddle-lever attached, are shown in plan, Fig. 3659. 
 
 Fig. 3656 is a plan of the sliding bracket for feeding the drill-spindle ; and Fig. 3657 is a plan of the 
 lever by which it is worked by means of the treddle and link I. 
 
 TORSION in mechanics is the twisting or wrenching of a body by the exertion of a lateral force. If 
 a slender rod of metal suspended vertically, and having its upper end fixed, be twisted through a cer- 
 tain angle by a force acting in a plane perpendicular to its axis, it will, on the removal of the force, un- 
 twist itself, or return in the opposite direction with a greater or less velocity, and, after a series of os- 
 cillations, will come to rest in its original position. The limits of torsion within which the body will re- 
 turn to its original state depend upon its elasticity. A fine wire of a few feet in length may be twisted 
 through several revolutions without imparing its elasticity ; and within those limits the force evolved is 
 found to be perfectly regular, and directly proportional to the angular displacement from the position 
 of rest. If the angular displacement exceeds a certain limit, the particles of the body will be wrenched 
 asunder ; or if the elasticity is not perfect, (as in a wire of lead, for example, before disruption takes 
 place,) the particles will assume a new arrangement, or take a set, and will not return to then- original 
 position on the withdrawal of the disturbing force. 
 
 The resistance which cylinders or prisms formed of different substances oppose to torsion, furnishes 
 one of the usual methods of determining the elasticity and strength of materials ; and the property which 
 a metallic wire or thread stretched by a small weight possesses of becoming twisted and untwisted in 
 a series of isochronous and perfectly regular oscillations, has been ingeniously applied in the torsion 
 balance to the measurement of very minute forces, and thereby to the establishment of the fundamental 
 laws of electricity and magnetism, and to the determination of the mean density of the earth. See Bal- 
 ance of Torsion. 
 
 The laws of torsion have been experimentally investigated by Coulomb in a variety of substances ; 
 as metallic wires, hairs, fibres of silk, &c. The method which he employed consisted in attaching a 
 body of given form and dimensions to the extremity of the wire, and, after twisting it through a certain 
 angle, to abandon it to the action of the force evolved, and observe the time of the oscillations. The 
 following general laws were found to hold good : 
 
 1. On loading a wire or thread with different weights, it will settle in different positions of stability; 
 that is to say, an index attached to the weight will point in different directions if the weight be varied, 
 and the angular deviation may amount even to a whole circumference. 
 
 2. The oscillations are isochronous. 
 
 3. The time of oscillation is proportional to the square root of the weight which stretches the wire. 
 
 4. The time of oscillation is as the square root of the length of the wire. 
 
 5. The time of oscillation is inversely as the square of the diameter of the wire. 
 
 From the second of these laws it follows that when the wire is twisted round from the position of rest, 
 the force with which it tends to return to that position is proportional to the angle to be described in 
 order to attain it. For it is a general result of mechanics that all motions produced by forces acting 
 according to this law have the property of tautochronism ; that is to say, the oscillations are performed 
 in equal times, whatever be the length of the arc. This fundamental property is usually enunciated by 
 saying that the force of torsion is proportional to the angle of torsion. 
 
 Let F denote the force of torsion, measured by the weight which it would be necessary to apply by 
 means of a pulley to a point p, situated at the unit of distance (one inch) from the axis of the wire, and 
 invariably connected with it, to cause the point p to describe an arc of a circle equal in length to the 
 unit of distance ; then, by the property enunciated, the force which must be applied at p in order that 
 the point may describe any arc <p is expressed by F' tp. If the arc of torsion is expressed in degrees 
 instead of parts of the radius, we have <p — rr <j>° •— ISO 0 (r being the semicircumference to radius 1, or 
 — 3-14159 ;) whence the expression of the force becomes F -|- tt <fi° ~ 180°.- 
 
 On this principle of the proportionality of the impelling force to the angle or deviation the problem 
 of determining the time of an oscillation is solved. Suppose a body of any form attached to the ex- 
 tremity of a slender wire, whose weight in comparison to that of the body may be neglected, and le( 
 
TRANSIT INSTRUMENT. 
 
 777 
 
 dm be an element of the mass, r the distance of dm from the axis of the -wire, and T the time of ar 
 oscillation ; the solution of the problem gives 
 
 m , / nr 2 dm\ „„ , nr 2 dm 
 
 1 ^ (/— ) ’ ° r T ' = ' 
 
 The integral J' r 2 dm is the moment of inertia of the attached body. If the body be a cylinder whose 
 axis coincides with that of the wire, and if a denote its radius and M its mass, then J'r 2 dm = \ Mu’; 
 or, substituting the weight for the mass, and observing that if the weight be denoted by P, and the 
 accelerating force of gravity by <7 (=321908 feet or 386.2894 inches in a second,) we have P = 
 
 M g,C r 2 d rn = P a 2 -f- 2 g. Hence the expression for the time becomes T = r a if — — . 
 
 If the attached body were a slender cylindrical needle suspended horizontally by its middle to the 
 wire, we should, on denoting its length by /, have J'r 2 dm = J M P ; whence T = 7r l if - — -. 
 
 The following results are deduced from the formula: 1. The force of torsion is independent of the 
 weight which stretches the wire, or F remains constant while P is varied. For suppose P to become 
 P', and let T' be the corresponding time of oscillation, and F' the corresponding force, we have then 
 
 „„ id ad P d ad P' 
 
 2 y F ’ 2#F' ’ 
 
 whence T 2 : T /2 : : P F' : P' F. But, by the third experimental law, T 2 : T' 2 : : P : P' ; therefore F' = F. 
 
 2. The force is inversely as the length of the wire. For, supposing P to remain constant, we have 
 
 T 2 : T /2 : : F : F. But, bv the fourth experimental law, T 2 : T /2 whence F' : F : : l : V. 
 
 3. The force is proportional to the fourth power of the diameter of the wire. Let there be two wires 
 of the same substance, but of different diameters, D and D', and stretched by the same weight P ; and 
 let T and T' be the corresponding times. By the fifth experimental law, we have T : T' : : D' 2 : D 2 . But 
 it has been shown that T 2 : T' 2 : : F' : F ; therefore F : F' : : D 4 : D' 4 . 
 
 To show the method of applying the formulae, we shall compute one of the experiments of Coulomb. 
 An iron wire was stretched by a vertical cylinder of '8 of an inch radius and weighing 2 lbs., and it was 
 observed to make 20 oscillations in 242 seconds, or one in 12'1 seconds. It is proposed to determine 
 
 ^2 p 
 
 the force F. From the formula for the time of an oscillation we have, by transposition, F : 
 
 a ' 2 = 64, P = : 
 
 1 9- 
 
 Substituting numbers in this formula, we have id — 9'8G96, 
 
 12'633 
 
 = 146'41 ; consequently F = -A — — = -0001117 of a pound, or about -78 of a grain 
 
 86 - 
 
 2 g T 2 ’ 
 2894, T 2 = (12-l) 2 
 
 Hence the weight 
 
 applied at the distance of one inch from the axis of the wire that would be required to twist the wire 
 through a complete revolution, or 360°, is 6'283 times this quantity, or nearly five grains. 
 
 For the demonstration of the fundamental formula, namely, T 2 F — id J'r 1 dm, see Coulomb, Theorie 
 des Machines Timples ; or Biot, Traite de Physique, tom. i. 
 
 TRANSIT INSTRUMENT for the correction of time-keepers. Mr. Dent had long felt persuaded 
 that the interest of Horology would be promoted if the public were more generally possessed of a 
 cheap, simple, and correct transit instrument, requiring little or no scientific knowledge for its right use, 
 and not readily susceptible of injury or derangement. To this end he had devoted much time and 
 thought; and, in 1840, he considered that he had succeeded in inventing an apparatus which, by means 
 of shadows, would produce the desired result. This idea he communicated to J. M. Bloxam, Esq., who 
 thereupon informed him that his own attention had for some years been devoted to the same object, 
 and that he had contrived an optical arrangement, which, by the agency of a single and double reflec- 
 tion, determined the sun’s passage over the meridian with great exactness. Convinced of the supe- 
 riority of Mr. Bloxam’s contrivance, Mr. Dent, in conjunction with that gentleman, after two years of 
 great labor and expense, produced the instrument in its present simple and accurate form. It has been 
 made the subject of a patent, and may be had, with complete instructions for its use, from the maker 
 and proprietor, Mr. Dent. 
 
 Fig. 3660 gives a general outline of the instrument, in readiness for taking observations. 
 
 3'&4' 3&4 l' 1 2 
 
 The Dipleidoscope operates by reflecting the sun’s rays by means of a simple combination of reflect- 
 ing surfaces. Bearing this in mind, and remembering also that the angle of the incident rays of light 
 falling upon a plane is equal to the angle of the reflected rays, the nature and action of the instrument 
 will be obvious from the figure. 
 
778 
 
 TRIP-HAMMER. 
 
 The instrument consists of three reflecting planes DC, D B, and B C, Fig. 3661. D C represents tlia 
 exterior plate of glass, which covers in the other two opaque glass surfaces D B and B C, set in the in 
 terior of the instrument. Suppose D C to be so divided that the ray No. 1 falling on D C, at E, will 
 be reflected to the eye at 1', and the image of the sun will appear to advance in the direction from 1) 
 towards C. The ray No. 2 passing through D C, is reflected from C B, impinges on D B, and reaches 
 the eye in the direction 2'. The image of the sun thus formed will appear to move from C towards D, 
 because it has been twice reflected, and thus the two images will approach each other. Suppose the 
 ray No. 1 to have advanced to the position No. 3, and the ray No. 2 to the position No. 4; it will then 
 be evident that their reflected rays will be in the same direction 3' and 4', and, therefore, that the two 
 images of the sun coincide, as shown by the arrows being in the position of crossing each other, and in- 
 dicating the instant of apparent noon ; as the rays continue to advance, the images, having passed over 
 each other, will, of course, be seen to separate. 
 
 The following familiar illustration is introduced to further explain the optical construction. When 
 the sun is about setting, it is not uncommon to see the rays so reflected from the windows of a whole 
 range of houses, as to convey the idea of a public illumination. While some portions of the sun’s rays 
 are thus reflected, other portions pass through the glass into the rooms. The rays thus transmitted 
 (the rays of incidence , as they were styled above) may be thrown at pleasure in any direction consist- 
 ent with the range of the sun, by a person within the room, having a looking-glass in his hand: exactly 
 as children produce what they call a Jack-o’- Lantern. Now if, instead of throwing the rays upon a 
 non-reflecting object, (sucli as the wall, die.,) he were to transfer them to another looking-glass, they 
 would be again reflected from this latter glass. Supposing these two looking-glasses to be placed at 
 an angle of less than 90°, in a manner corresponding with the position of the two silvered planes seen 
 in the instrument, and also shown in the figure at D B, B C, he can reflect the sun’s rays again out of 
 the window. Now, if we imagine the window to represent the outer reflector of the meridian instru- 
 ment, its construction is, by this process, completely exemplified. To proceed a little further; it is 
 evident, that the angle and situation of the two looking-glasses could be so arranged as to direct the 
 rays of the sun through any particular pane of the window ; so that a person standing without, in a 
 proper position, would see, in addition to the sun’s rays reflected from the outer surface of the pane, the 
 rays of incidence that had passed through the window, and were thus reflected from the double mirror. 
 One of the luminous objects (the flash or glare of the sun) so produced, would be reflected from the 
 surface of the window, and would be a single reflection ; while the rays of incidence, which had passed 
 through the window, and undergone a double reflection by means of the two mirrors would, on being 
 thrown back by the mirrors tlirougli the window, move in a direction contrary to that taken by the 
 single reflection from the surface of the window-pane. Hence, any one of, the heavenly bodies, sub- 
 jected to the eye by a process of the above description, would not only appear as two distinct objects, 
 but those objects would be seen to approximate and cross each other in an opposite course : a desidera- 
 tum being hereby secured which increases the power of the instrument in a double ratio, and renders it 
 proportionably preferable to any other that has been hitherto employed. 
 
 The Dipleidoscope, or new patent meridian instrument, will enable any person to obtain correct time 
 with the greatest facility, by an observation either of the transit of the sun over the meridian by day, or 
 of the transit of the stars by night. It possesses great advantages over any other of similar correctness ; 
 it is exceedingly simple, it is not liable to get out of adjustment or repair, and it does not require any 
 attention beyond that which is, of course, necessary in the first instance, viz., that it be placed on a 
 level surface, and in the meridian. The observations to be taken afterwards can be made by any one, 
 although previously unacquainted either with astronomical apparatus or practical astronomy ; the in- 
 strument being as simple as a sun-dial, while it is infinitely more correct, since it gives the time to 
 within a fraction of a second. The utility of possessing an indicator of this kind in addition to the most 
 perfect time-keeper, must be evident : for, however excellent a clock or watch may be, experience 
 shows how difficult it is to obtain exact time, for lengthened periods , by any mere mechanical contriv- 
 ance. To remedy the defect of mechanism, it has been already remarked, that actual observation of 
 the heavenly bodies becomes indispensable ; as, without it, the best time-keeper cannot be implicitly 
 depended upon for any considerable interval. 
 
 TRIP-HAMMER. Fig. 3662 is a side elevation of a small trip-hammer, such as is commonly used 
 /or forging spindles and bolts, and for swaging various other kinds of small work 
 
TUBE-MAKING MACHINERY. 
 
 779 
 
 Fig. 3663 is an end elevation of the same, A is the driving-pulley, with a flanch on each side to 
 guide the belt while running loose. This pulley is attached to the cam-shaft, upon the other end of 
 which is the balance-wheel E. C a foot-lever, connected with the catch b , by a rod and spring, and by 
 means of which the hammer can he stopped or started without shipping the belt. F, bed of timbers 
 bolted together to support hammer. G, post in which the hammer-block is placed — usually extending 
 into the ground four or five feet, f is the husk-supporter or rocker, adjusted by screws and bolts, so 
 that the hammer can be set at any taper. S is a heavy cast-iron bed-plate to which all other parts are 
 connected. This plate is bolted firmly to the timbers below. 
 
 TRIP or TILTING HAMMER. From the Lowell Machine Shop. Figs. 3661 and 3665 are side 
 and end elevations of a tilting hammer, with a head weighing 250 lbs. 
 
 a is the driving-pulley. As the Delt runs loose around the pulley when the hammer is not in use* 
 here is a flanch on each side to keep the belt in its place. 
 
 B, large timbers on which the heavy iron-work rests. 
 
 P, timbers disconnected with B, which support the block S in which the lower die is fastened. 
 
 3665. S6G4. 
 
 e, a spring of the best kind of timber, which serves as a stop for the hammer when raised, and gives 
 force to the blow. 
 
 b is the cam, which raises the hammer twice in one revolution. 
 
 The hush of this hammer is hung in a rocking stand, adjusted by set-screws and bolts, so that it can 
 be set at any taper for drawing tapering work. 
 
 This hammer is well adapted to swaging car-axles, Ac. 
 
 TUBE-MAKING MACHINERY — Deakin’s improvements, 1850. The patentee’s invention relates 
 to rolling machinery for the manufacture of metallic cylindrical, taper, and other tubes and solids 
 
 3666. 
 
 Fig. 3666 represents a longitudinal vertical section of the machinery for making tubes, taken centn- 
 cally through the rollers at the line 1, 1 ; Fig. 3667 is a plan view. A A, the side framing of the ap- 
 paratus, upon which are mounted the four pairs of rollers, B B B B. The patentee does not, however, 
 confine himself to the employment of this number of rollers in each apparatus, as a greater or less num- 
 ber may be used, but he prefers this number generally, as most advantageous. These rollers are con- 
 nected together by means of spur-wheels, so that the surface velocities of the rollers acting immediately 
 upon the metal passing between shall be equal, although the diameters of such rollers may be unequal 
 or equal, as most convenient. Immediately in front of the first pair of these rollers B B are placed tk* 
 
780 
 
 TUBE-MAKING MACHINERY. 
 
 pair of rollers C C 1 , the centres of the shafts of these rollers being in a direction at or near right angles 
 to those of the rollers B B, and therefore revolving at right angles to them. The peripheries of the roll- 
 ers B B are all concave, the concavity of the first pair from the rollers C C l being greater than the con- 
 cavity of the other pairs, and this concavity decreases in each pair of rollers until the last, in which the 
 two concavities of the rollers form together a circle. The peripheries of the two rollers C C 1 are differ- 
 ent from each other ; that is, one of them, as C, is convex, and the other, C 1 , is concave. The lower ends 
 of the vertical shafts D D, carrying the rollers C C 1 , revolve in steps, E 1 , E 2 , upon the bed-plate F, which 
 thereby supports the weight of them and the rollers. The rollers are geered together by spur-wheels, 
 and the requisite rotary motion is given to them and to the rollers B B by any well known and conve- 
 nient means. G represents the plate or skelp of metal in the process of being bent and formed into a 
 tube. The flat skeip is previously heated in a suitable furnace, and then passed through the machine, 
 first between the convex and concave rollers C C 1 , by which it is bent from its previous flat form, and 
 assumes that of the peripheries of the rollers, being about semi-cylindrical, of considerably larger diam- 
 eter or radius than that of the intended tube, and then passes on to the first pair of the horizontal rollers 
 B B, by which the edges of the skelp become further bent round, and begin to approach each other, and 
 this rounding gradually goes on in the passage between the remaining pairs of rollers. In passing be- 
 tween the second pair of rollers, the edges are caused to approach nearer together ; the action of the 
 third pair brings the edges into contact, and the last pair effects the closing or welding of the joint. 
 When the whole formation of the tube is intended to be effected at one operation of the machine, it is 
 necessary that the skelp should be at a welding heat when passed into the machine. Thus it will be 
 seen, that at one operation of the machine, the flat plate or skelp will be bent up to the cylindrical form, 
 the joint welded up, and the perfect tube produced at one heat of metal. This result, however, cannot 
 always be obtained, as when very thin plates or skelps are used for the manufacture of tubes. In this 
 case the metal cannot be retained at a welding heat sufficiently long to insure a perfect junction of the 
 edges of the skelp at the last pair of rollers, therefore the skelp is bent up to the tubular form, and the 
 edges brought together at the first operation, preparatory to the welding process, which the patentee 
 then effects by passing it, at a welding heat, between the rollers of a second machine of similar construc- 
 tion to that previously described, but not having any rollers similar to these, C C l . The rollers B B are 
 sometimes arranged in vertical positions, instead of horizontal, as described ; the rollers C C 1 will like- 
 wise be reversed in their position, but their action on the skelp and the result will be precisely the 
 same as by the first arrangements. 
 
 The next improvement consists in the means of manufacturing taper tubes. The machinery em- 
 ployed for this purpose is the same as that previously described for manufacturing cylindrical tubes, 
 except that one or more of the pairs of rollers employed, instead of having their grooves regular, and 
 of equal size throughout the whole of their peripheries, are formed of varying sizes, either increasing or 
 decreasing, according as the tube to be manufactured is required to be produced of increasing or de- 
 creasing diameter. One of the rollers is represented in section, Fig. 3668, which shows the form of the 
 
 36CS. 8CC9. 
 
 groove. It will be seen that proceeding from the cutter I 2 , Fig. 3668, in one direction round the roller, 
 the size of the groove is gradually increased until it arrives at the same point, which is the junction of 
 the greatest and smallest portions of the groove ; proceeding in the other direction from the same point 
 the reverse obtains, the corresponding roller working with the one shown in section, both being grooved 
 in a similar manner, so that when working together they present a circular passage of gradually vary- 
 ing diameter, and thereby produce a tube, the taper of which corresponds with the varying size of the 
 grooves ; the variation in the sizes of the grooves will of course depend upon the degree of taper the 
 manufactured tube is required to have. The patentee sometimes employs taper plates or skelps of 
 metal in the manufacture of taper tubes, by means of the above-described machinery ; and when he re- 
 quires to manufacture tubes with the interior cylindrical, and taper upon the exterior, he then employs 
 skelps of metal of unequal thickness. The means adopted for forming and making the varying grooves 
 in the rollers, so that they shall present a smooth surface, and also that their variations shall be perfectly 
 regular and uniform throughout the circumference, is this : — It consists of a frame or head-stock H, Fig 
 3668, fitted in bearings, in the top of the uprights of which is mounted the shaft or mandril H 1 , upon 
 which is fixed the driving cone of pulleys or wheels, H 2 , by which the requisite rotary motion is given 
 to the mandril H : the mandril is hollow, and slotted upon opposite sides. A rod I passes into the hol- 
 low of the mandril from one end. The inner end of the rod is pointed or wedge shaped, and passes 
 into, and bears against a corresponding recess in the end of the cutter I 1 , which is of two or more parts, 
 the cutting-edges of which pass through the slots in the sides of the mandril, and project beyond it 
 
TUBE-MAKING MACHINERY. 
 
 781 
 
 The rod I is caused to traverse along the mandril by means of the screw I 2 , passing through a bracket 
 fixed to the back of the upright carrying the open end of the mandril, the end of the screw bearing 
 against the end of the slotting-rod I, so that as the screw is screwed up, it causes the cutter to expand 
 by acting on the rod. The cutter is, of course, carried round with the mandril. A spur-pinion is fixed 
 upon the screw I 2 , by which a slow but regular rotary motion is given to it, by which the expansion of 
 the cutter is effected at a regular and uniform rate. The rollers L L are mounted upon shafts in a 
 carrying-frame, in position shown, the groove to be cut off, one being above and one beneath the cutter. 
 A slow rotary motion is given to the rollers, both moving at equal velocities, at the same time that a 
 rapid motion is given to the mandril and cutters ; when the cutter is in the position shown in the draw- 
 ings, the largest part of the groove required will be cut, because the largest part of the cutter is then 
 in the plane passing through the two centres of the rollers; but as the cutting progresses, the size of 
 the groove cut will gradually decrease, by reason of the cutter being caused to traverse along the man- 
 dril, when the small part of the cutter comes gradually into action, until the rollers have made one 
 revolution, when the cutter will have traversed so far that only the small end of the cutter will be in 
 action, in cutting the smallest part of the groove, where the junction with the largest part of it takes 
 place. The degree of variation of the grooves cut in the peripheries of the rollers will depend upon the 
 form and length of the cutter, and amount and rate of traverse given to it, in relation to that of the 
 rollers upon their axis. In manufacturing other forms of tube, the patentee employs the cylindrical 
 tubes in the manner before described, which are reheated and passed between rollers, the peripheries 
 of which are of such a form as to cause the tubes to assume the exterior form desired. A pair of rollers, 
 the forms or shapes of the peripheries of which are such as to compress the cylindrical tubes between 
 them, and into the form of a hollow railway rail, are shown in Fig. 3671. 
 
 Fig. 3669 shows an arrangement of these rollers, OOO, placed triangularly, for compressing and roll- 
 ing cylindrical tubes into hollow trilateral forms, suitable likewise for railway rails, the peripheries of 
 the rollers being of such shapes as to produce the forms required. 
 
 Fig. 3670 shows the hollow trilateral rail produced, and rolled by the arrangement of rollers, as shown 
 
 Fig. 3669. 
 
 3670. 3673. 
 
 <3» 
 
 Fig. 3675 is another form of hollow trilateral rail, slightly differing from the preceding. 
 
 Fig. 3673 represents a cylindrical tube. 
 
 Fig. 3674 is a taper tube, the interior and exterior being of uniform tape) - , and of equal thickness ol 
 metal throughout. 
 
 Fig. 3672 represents a tube tapered exteriorly, and cylindrical interiorly, and of an equal thickness 
 of metal. Mandrils may be employed or not in the above modes of manufacturing tubes, as convenient. 
 
 The next improvement relates to the manufacture of spiral or helical metal tubes. This improve- 
 ment is illustrated in Fig. 3676, which represents an elevation of the apparatus. The apparatus con- 
 
 sists of a pair of rollers P P, mounted one above the other in the framing QQ, the bearings in which 
 the rollers revolve being in the uprights Q 1 Q 1 of the framing, and the mode of attachment to the bear- 
 ings being such that the rollers may be removed or replaced with facility, as it is necessary to remove 
 the rollers from the frame before the spiral or helical tubes can be removed from the rollers. These 
 rollers are geered together at one end by the geering-wheels P 1 P 1 , so that they revolve in unison. The 
 peripheries of the rollers are formed with spiral grooves T T, around which the direction of the spiral 
 of one is in one direction, aud that of the other is in another direction, so that as the rollers revolve, the 
 grooves of one always coincide with the grooves of the other, and the two together form the extei ior 
 of the spiral tube, as is the case with grooved rollers generally. The grooves may be of any form so 
 as to manufacture the spiral or helical tubes of any form of cross-section desired. Motion is given to 
 tlie rollers by any convenient means. When a spiral tube is to be formed, the tube is previously man- 
 ufactured cylindrical, or of other shape suitable for the purpose, and as the rollers P P revolve, one end 
 of the tube is applied to the grooves in the rollers at or near the smaller ends of them, or the 'everse, a 
 
782 
 
 TURN-TABLE. 
 
 catch being provided to secure it, and as the rollers revolve, the tube will be drawn between them, and 
 coiled along the spiral grooves T T, thus forming the spiral tube required, and when the tube has been 
 formed, the machinery is stopped and the rollers removed from their bearings, when the spiral tube 
 may be drawn off. The rollers are then replaced in their bearings preparatory to another operation. 
 The rollers may be formed with any required degree of taper, so as to manufacture tubes of correspond- 
 ing forms, and the spiral grooves may be made so as to produce spiral tubes either regular or irregular 
 in the pitch of the spirals, increasing or decreasing, as required. When it is required to manufacture 
 helical tubes, the patentee employs cylindrical instead of taper rollers, and proceeds as before described, 
 with respect to spiral tubes. By this improved machine the patentee is enabled to manufacture spiral 
 or helical tubes, in which the direction of the spiral or helix shall be either right-handed or left-handed. 
 This is effected simply by causing the straight tube to be coiled during the process, and wrapped 
 around either one or the other of the two rollers, the grooves of one being right-handed, and the other 
 left-handed, and therefore a correspondingly formed tube is oroduced. 
 
 TUNNELS. From an examination of James Hayward, Esq., C. E., before a Committee of the Mas- 
 sachusetts Legislature. 
 
 Mr. Hayward visited Europe and examined as many as thirty tunnels. The Marseilles Tunnel i. 
 located at Nerthe near Marseilles, is three miles (15,153 feet) long, and has twenty-four shafts. The 
 material in this tunnel is a very hard limestone. The height of the ground over it is a little over 600 
 feet. The aggregate length of all the shafts is 7,589 feet ; the deepest shaft is 610 feet. The cost per 
 yard down, for excavation, was $43. The shafts are nine feet in diameter, and are lined with masonry, 
 at a cost of $19 40 per yard down. 
 
 The deepest shaft cost $73 per yard down, entirely completed. The entire cost of all the shafts for 
 the masonry amounted to $47,000 ; and $150,000 for the whole cost of the tunnel. The entire cost of 
 the tunnel for the contractor was $125 for the lineal yard; this includes shafts. The tunnel was lined 
 with masonry of ditferent thicknesses, and cost $423,000. The entire cost of the tunnel, exclusive of 
 masonry, was $705,000. 
 
 Woodhead Tunnel between Manchester and Sheffield, is a little over three miles long, and the hill 
 over it 600 feet high. It has five shafts, 10 feet in diameter, which vary from 400 to 600 feet in depth. 
 The character of theroek is granite, not so hard as our granite; it is called there “Mill-stone rock.” 
 The tunnel was about five years in construction, and its whole cost was $1,026,705. 
 
 There are various ways of ventilating the tunnel while the miners are at work, and it is easily done. 
 It was supposed that the shafts would be necessary for ventilation in the Woodhead Tunnel, as the cars 
 passed through it, hut they are now closed. Mr. H. gave an explanation of the various modes that are 
 adopted for ventilation. In the mines in Cornwall, there are excavations extending 30 miles under 
 ground. There are tunnels in the Duke of Bridgewater’s Canal, which make, in the aggregate, thirty 
 miles. On the Thames and Medway Canal, there is a tunnel about two miles long. The shafts by 
 which it was originally constructed, except one in the centre, are closed. The tunnel is used both for 
 a railway and canal, and trains pass through it every half hour daily. Gen. Paisley, the superintendent 
 of public works, passed nearly a day in the tunnel, and he says that the smoke and steam from the 
 trains passed almost immediately away. There was a constant current of air through it. 
 
 The Box tunnel, on the Great Western Bailway, about 100 miles from London, is the largest and 
 most expensive tunnel ever constructed ; it is 39 feet high, and over 30 feet wide. The shafts were 25 
 feet in diameter, its length is 9579 feet. Over one-third of it is through the solid rock. 
 
 Upingham Tunnel, 1320 feet in length, cost £25 per lineal yard. Pulpit Rock Tunnel, Pennsylvania, 
 a difficult tunnel on the Beading Road, cost $66 20 pier lineal foot. Gen. Barnard gave to Mr. Baldwin, 
 in answer to some inquiries, the cost of five tunnels, the highest of which was $4 36 per cubic yard. 
 
 TURBINE. See Water AVheel. 
 
 TURN-TABLE. A contrivance on railroads by means of which the engine or cars may be turned 
 round. This is effected by excavating a pit under a portion of the track, and laying in the bottom of 
 this pit a circular track, upon which a platform, supported by friction-wheels, is made to revolve. A 
 great many plans have been devised to effect this object. The following is the method of constructing 
 the iron turning platform used in England. 
 
 These tables are thus constructed: oo, Fig. 3680, is the surface of the ground whereon the rails of 
 the railway are laid, a circular hole being dug of sufficient depth to receive-the table ; around this, large 
 stone blocks a a, similar to the railway blocks, are placed ; upon these blocks eight cast-iron chairs, rep- 
 resented at bbb, &c., Fig. 3681, are placed, and pinned down; a circular ring of cast-iron cc is laid 
 within these chairs, about two inches and a half broad at top, and a little bevelled ; this ring is laid 
 perfectly horizontal, and upon it the small bevelled rollers gg g, &c., revolve, the arms 1, 2, 3, 4 acting 
 as axles to them, and around the ends of which they turn freely. These arms pass through a ring oi 
 
 iron near the extremity, which keeps the rollers constantly in their proper position ; the arms are fast- 
 
 ened in the centre to a ring of irony) which turns freely round the spindle/', Fig. 3680. The turn-table 
 rests upon these rollers, which are for the purpose of causing it to turn round as freely as possible. 
 Fig. 3682 shows the framework of the table ; hhh, (fee., are the outer rim ; Hi the arms ; and m n the 
 inner rim, which is of the same diameter as the ring of iron cc c, and which rests on, and turns lound 
 upon, the periphery of the rollers gg g- The table is kept in its place by the vertical spindle f fixed 
 
 upon the table at e, and turning with it upon the rest e'. 
 
 The table, it will therefore be seen, turns round this rest as a centre, and revolving upon the periph- 
 ery of the rollers, it moves round with very little friction. It is not intended that the spindle f should 
 support any part of the weight of the table, the use of it being solely to prevent any side motion. The 
 outer ring ll of the table projects above the level of the arms i i and the inner part of the ring h' h' 
 Within this outer ring a platform of timber is laid, resting upon and fastened to the arms kk, the bolt 
 holes being shown in the figure; upon this platform the rails of the road are placed -m, Fig. 368U 
 
TURN-TABLE. 
 
 783 
 
 stows the timber, the upper side of which is level with the top of the cuter ring h h. A circular ring 
 o o of cast-iron, or of mason-work, is laid around the outer circle of the table, upon which the rails rest, 
 and which abut against the ends of the rails laid upon the turn-table. 
 
 We have said that the top of tl e turn-table is covered with timber, on which the rails forming tha 
 railway is laid ; in many cases the top is formed of cast-iron, the rails being raised a little above the 
 surface of the cast-iron plate. 
 
 3683. 
 
 A very much improved form of table is that of Mr. Aldrich, of Worcester, Mass., which is extensively 
 used in New England, sometimes as large as 48 feet in diameter. A plan and section is shown in Figs. 
 S6S3 and 3684. It will be seen that in this table the wheels are fixed to a framing independently of the 
 table ; in fact, the principle being the same in many respects as the one above described : the number of 
 
784 
 
 TWISTING MACHINE FOR IRON. 
 
 friction-rollers is however much greater, and on the whole the arrangement is superior to the English 
 tables. This wheel is turned by means of a pinion working into the toothed segment shown in plan 
 Fig. 3683. These tables are of wood, and were originally patented. The arrangement is shown in the 
 figures so clearly as to require no further description. * 
 
 3084. 
 
 TWISTING MACHINE FOR IRON — Melling’s. The great advantages of obtaining perfect 
 
 homogeneity of matter in metal surfaces over which heavy loads are passed, either with an abrading or 
 rolling movement, is obvious ; and by a very simple process a vast increase in permanency may be con- 
 ferred upon articles of this class as well as upon various others, as axles, shafts, connecting-rods, and 
 piston-rods. In shafts, for instance, where the mass is built up out of a series of bars, flaws are of fre- 
 quent occurrence, through imperfect welds ; and where the weld is good, a deficiency in strength and 
 durability is generally the resulting effect of the parallelism of the fibre. 
 
 To overcome this practical mechanical difficulty, Mr. Melling, of the Rainhill Iron Works, Liverpool, 
 has proposed to twist together the bundles of constituent bars which go to form a shaft, or other forging 
 of large size, and for this end he has devised and introduced the machine which forms the subject of 
 our figures. This machine has now been in operation for a considerable period ; it is not, therefore, 
 held up simply as a novelty, but as a valuable workshop accessory. 
 
 Fig. 3685 is a complete longitudinal elevation of the machine in working order, having the front 
 heavy driving geering removed to avoid obscuring the twisting details. In the same view are also 
 shown the carriages on which the bars under treatment are conveyed to and from the machine. 
 
 Fig. 3686 is a corresponding plan, partly in section, showing the driving geering. In this view a bar 
 is represented as in the act of passing through the twisting rollers. 
 
 Fig. 3687 is an end view, looking upon the delivering rollers. 
 
 3085. 
 
 Fig. 3688 is a side elevation of a modification of the delivering rollers, differing slightly from the same 
 portion in Fig. 3687 in point of regulation of the upper roller-bearing. 
 
 Fig. 3689 is a front elevation of the first or revolving set of rollers, exhibiting the actuating mechan- 
 ism whence the revolving movement round the axis of the twisting bar is obtained. 
 
 Figs. 3690, 3691, 8#92, 3693, 3694, and 3695 represent various kinds of work, as finished from the 
 original pile of bars. 
 
 The machine stands upon a massive foundation of masonry, to the surface of which the cast-iron bed- 
 plate is b( Ited. The driving power is communicated to the shaft A, from which motion is communi- 
 cated through the pair of wheels B B to the transverse shaft C C, passing right across the macliine, and 
 having a heavy fly-wheel D at its opposite end. From this shaft the first pair of rollers E E, from their 
 peculiar movement distinguished as the revolving rollers, are worked by the worm F, which geers with 
 the large worm-wheel G, cast in one piece with the back of the plate H, and bored out at the back to 
 work upon a fixed carrier bolted to an upright bracket fixed to the back part of the bed-plate. The 
 shafts T T carrying these rollers are supported in four bearings K K, fitted into a pair of transverse 
 cheeks L L, bolted and keyed between the two plates H M. The latter is supported by a corresponding 
 plate N, into which is fitted a turned ring cast on the front of the plate M, and this Dlate N is again 
 
TWISTING MACHINE FOR IRON. 
 
 735 
 
 bolted to flanges 0 0 on the upright cheeks of the delivering rollers. It is easy to see how by this ar- 
 rangement the revolution of the main shaft C communicates a revolving movement to the frame-work 
 carrying the rollers E E ; but in addition to this movement they revolve also round their own axes, and 
 this is obtained by means of the t»o plates H and M, which carry round with them two small spur- 
 pinions P P, geering with the fixed toothed rim Q. This motion is then transmitted from these pinions 
 *o the rollers, through the two worms R R upon their shafts, to the two worm-wheels cut upon the 
 roller-shafts. 
 
 3U80. 
 
 In the plan, Fig. 3686, the machine is shown as thrown out of geer with the driving-shaft, whilst a 
 a bar S S is passing through. This disengagement is effected by the two lever-handles T T acting each 
 one upon a clutch-box, corresponding with similar clutches on the worms v and v, the latter being that 
 through which motion is communicated to the front delivering rollers, which latter may be thrown 
 in or out of geer by the attendant, when on .the opposite side of the machine, by means of a short 
 handle at v. 
 
 3087. 
 
 The lower of the two delivering rollers W W, which simply revolve round their own axes, receiver 
 its motion from the main shaft, through the worm geering with the worm-wheel X on the second trans- 
 verse shaft Y, carrying a pinion Z geering with a similar one on the lower roller-shaft. The object in 
 giving motion to the lower roller first being to admit of the raising and lowering of the upper one as 
 Von. II. — 50 
 
786 
 
 TWISTING MACHINE FOR IRON. 
 
 may be required to suit the work, the upper being driven from the lower one by the pair of pinions a a 
 on the opposite side of the roller-standards b b. In the combined views of the machine, the pressure 
 upon the upper delivering roller is represented as obtained from the weight c, adjustable on the long 
 lever d having its fulcrum at e, and pressing upon the journals of the upper roller by the two spindles //. 
 Crane-power may be applied to raise or lower this weighted lever, by attaching a chain to either of the 
 two loops formed for the purpose, both on the weight and on the lever. In Fig. 3685 the office of this 
 weighted lever is represented as supplied by a pair of adjusting screws pressing upon the upper rcller- 
 bearings. 
 
 3088. 
 
 The bars to be operated upon are brought from the furnace in the carriage g g, running upon four 
 wheel? on a tramway. The body of this carriage carries two brackets supporting a cross-shaft, on which 
 are two pulleys li h, employed for the withdrawal of the bars from the furnace. The pulley-shaft is 
 worked by a short winch-handle, as in Fig. 3686, and the ends of the two chains, coiled on the pulleys, 
 are attached to a box which is slipped over the bar whilst in the furnace. Guides are attached to the 
 carriage at k k for the support of the bar or pile of bars to be twisted ; and to admit of their free revo- 
 lution they are turned on the outside and fitted into the cast-iron rings, bored to correspond. These 
 
 3690. 
 
 3691. 
 
 3692. 
 
 oearmg-nngs are put together in halves, and are carried upon a pair of parallel longitudinal rods con 
 nected with the body of the carriage, or they may be simply suspended from a crane. The carriage for 
 receiving the twisted bar, as delivered from the machine, is at l on the opposite or delivering end. It 
 is nothing more than a semicircular iron trough, mounted upon a pair of wheels, with a drawing handle. 
 
 3694. 
 
TYPE FOUNDING, 
 
 787 
 
 The bar or pile of bars being entered between the revolving rollers, and passed through until the end 
 reaches the delivering pair, the upper one of this latter pair is pressed hard down upon it, so as to pre- 
 vent it from turning. Being thus firmly held at this end whilst the after portion is carried round by 
 the revolvers, it is clear that a twist must take place, an$ so the simultaneous revolutions of each pair 
 upon their own axes carry forward the bar ; it is preserved perfectly straight, and an even and regular 
 twist is given to it. Fig. 3690 is the original pile of rectangular bars; fig. 3691 represents these bars 
 as twisted together previous to the subsequent finish under the hammer. In fig. 3692 the twisted metal 
 is shown under the form of a double-T rail. 3693 is an axle formed out of round bars twisted together, 
 and welded only at each end for the wheels and journals ; and fig. 369-1 is a tire-bar exhibiting the stri- 
 ated texture, as in fig. 3692. . . . 
 
 TYPE FOUNDING. There are two kinds of fonts which are used respectively for book printing and 
 job printing, the latter including such work as hand and posting bills, etc. Book types include eleven 
 or twelve regular bodies, from Great Primer, which is the largest, to Pi&mond, which is the smallest 
 type used for printing books. The following are specimens of book types : 
 
 Great Primer, 
 
 English, 
 
 Pica, 
 
 Small Pica, 
 
 Each of the above fonts of type consist of five alphabets, viz. : A, a, a, A, a, together -with many 
 other characters, about 200 in all, and these must all be exactly alike, except in device and width. The 
 greatest width is for the W and M, and the least for the i and ! . 
 
 Every one of these numerous characters requires for its formation a punch, a matrix, a mould, and 
 type metal in a fused state. The punch is a piece of steel with a single letter at one end. It is formed by 
 hammering down the hollows and filing up the edges of the metal in a softened state. Each letter must 
 harmonize with all the others in the font with regard to height, breadth of stroke whether heavy or fine. 
 
 The matrix is a small piece of copper about 1 ^ inch long, -j) inch deep, and wide in proportion to the 
 size of the type : into this the hardened punch is struck. This must be managed with care, so as to 
 allow the faces of the types, when composed or set up, to be in a perfect plane. Hence the depth of the 
 impression in the matrix is of great importance, and it is usual to adjust this depth by filing down the 
 surface of the copper. The matrix having thus received a sunken impression from the raised letter on 
 the punch, all that is required is to pour a quantity of fluid metal into the matrix in order to reproduce 
 the letter as it is engraven on the punch. But in addition to this the cast letter will require a support, 
 or body, an appropriate width, and certain nicks or notches, which enable the compositor to place the 
 letter in the proper position in his composing-stick without having to examine every letter by eye. The 
 measure of the type with regard to height, width, and body, is determined by the type mould. The 
 mould is made in two parts, so contrived that on being put together, the two halves form in the centre 
 a space or mould, in which the type is formed : the matrix is placed at the bottom of the mould, and is 
 retained in its place by a spring. By sliding one part upon the other, the square cavity in the centre, 
 while retaining the same height, would have its width diminished to any extent required. The extent 
 to which the two parts of the mould slide upon each other is determined by the width of the matrix. 
 The metal is poured in at the orifice formed by closing the upper parts. 
 
 These details being understood, a few words will suffice to explain the operation of casting. The 
 caster stands by the side of a furnace containing the melting-pot and the fused type-metal (see Metals 
 akd Alloys). He holds the mould in his left hand, and taking up a portion of the metal, in a very 
 small ladle, held in the right, he pours a sufficient quantity of it into the mould, and immediately jerks 
 it up for the purpose of expelling the air from the cavity and driving the metal into the finest strokes of 
 the matrix. Then, by means of one finger, he releases the spring, separates the mould, and hooks out 
 the letter. The small and the large sizes require more time : the former, on account of the increased 
 care, and the latter, to allow the metal to set. 
 
 The types are removed from the caster’s table by a hoy, who, seizing the type by the edges, breaks 
 or bends off the superfluous metal at the bottom ; lie then conveys them to a man seated at a table, 
 who, with his finger protected by a piece of tarred leather, mbs the side of every letter on a slab of 
 gritty stone for the purpose of removing knobs or globules. The letters are next set up by a boy, in 
 lines, in a long stick, or shallow frame, -with the faces uppermost, and the nicks outwards. With the 
 assistance of other frames, a man called the dresser polishes the types on each edge, and turning them 
 with the face downwards, planes the bottom, and planes the groove which brings the types to the re- 
 quired height, and enables them to stand steadily ; the letters are carefully inspected -with a lens, and 
 the font being proportioned, i. e. the proper proportion of each letter, together with the spaces, quadrats, 
 etc., being counted out, each letter, Ac., is tied up in lines of convenient length for the printer. 
 
 TYPE SETTING MACHINE, or COMPOSING APPARATUS. For a series of years it has been 
 attempted to supersede manual labor in composing by machinery. The most successful thus far is the 
 invention of William H. Mitchel, of Brooklyn, which has now been for some two or three years in prac- 
 tical operation, in John F. Trow’s establishment. Fig. 3695 represents a perspective view of the ma- 
 chine : g g are conductors placed in a range, and eacli conductor allowed to a particular letter or charac- 
 ter, and a range of finger keys marked with corresponding character are so arranged that upon striking 
 one of said keys, the bottom type in the conductor with which it is connected, drops on to a correspond- 
 ing endless belt m, of a series of belts of successively increasing length, or speed, towards the deliverin 
 or composing part of the machine, which belt delivers the types on to a diagonal belt o, in' such 
 
 Fong .Primer, 
 
 Bourgeois, 
 
 Brevier, 
 
 Minion, 
 
 Noapariel, 
 
 Pent], 
 
 w 03 
 
788 TYPE DISTRIBUTING AND TYPE SETTING MACHINES. 
 
 manner, that they reach the composing wheel p in the order in which the keys are struck. The type: 
 are delivered upon the composing wheel hv an inclined conductor. The composing wheel delivers the type 
 in an upright position to the composing slide, from which they are taken and justified by the workman. 
 
 * 
 
 TYPE DISTRIBUTOR. Mr. Mitchel has also invented a simple and efficient distributing machine, 
 of which the following is his description. 
 
 “ Before the types are made use of or composed, each letter of the font is prepared, by cutting or 
 otherwise forming (as the assorted letters are set up in line) one or more grooves or notches in the body 
 of the type at a certain distance or distances from its bottom or lower end, each respective character 
 having its notch or notches differently located relatively to the lower end of the body from those of any 
 other varieties of letters or types, and around the edge of the wheel pins are inserted near the bottom 
 of each groove therein, which pins, by the notches before mentioned, sustain the types in different posi- 
 tions, according to the position of the notch or notches in the types ; hence, as said types are carried 
 along on said pins, each respective letter is dropped into a groove or receptacle provided for it when it 
 arrives opposite to said receptacle, by its lower end taking an off-set or incline, which removes the 
 t} r pe from its pin ; or any suitable means may be made use of to deposit the type in the receptacle 
 adapted to its peculiar position on the revolving wheel ; and by a peculiar arrangement of double 
 notches, a very great number of separate characters of types may be distributed to their respective re- 
 ceptacles by a very simple arrangement of inclines and off-sets. The lines of types in the receptacles or 
 grooves are successively pushed along to give room for the succeeding types, and a stop motion is used, 
 by which any misplaced type arrests the rotation of the machine. 
 
 TYPE DISTRIBUTING- MACHINE, Beaumonts Patent. This machine is automatic and distributes 
 with perfect accuracy every thing but two-em and three-em quadrats, without any attendance except to 
 supply the matter at short intervals. The types are carefully picked apart and are left standing in lines 
 suitable for a type-setting machine, or tumbled unceremoniously into boxes, as may be desired, the lat- 
 ter being easier as requiring less labor and care in their removal by the attendants. The principle on 
 which the machine is able to discriminate and put each type in its appropriate place, is that of feeling, 
 not the face, but the sides of the body. Each type is prepared expressly for the purpose by cutting 
 three nicks on its edges, differently arranged for each letter. The letter a, for example, is manufactured 
 with three nicks, called one, two and three, counting from the highest ; c has one, two and four ; b has 
 two, three and five, etc. The channel leading to each box is provided with a mouth of the same form, 
 carefully executed in hardened steel to withstand the wear, and the lines of type are pressed up succes- 
 sively against all these channels until the right one is presented, when the first type in the line pops in, 
 leaving the next to commence a similar round. The receiving channels are arranged in a circle, faces 
 inward, and the lines of type to be distributed are ranged radially in a horizontal wheel of somewhat 
 less diameter. This wheel is properly geared and rolls around within the enclosure, presenting each 
 type rapidly, but gently, to every aperture. The lines are thrust outward in the wheel by suitable 
 springs, which are simultaneously compressed by a simple movement when it is desired to supply more 
 matter. In wmrking out the details of this machine the most beautiful simplicity has been arrived at, 
 and every type is seized, on entering its proper channel, by a spring lever of sufficient force to tear it 
 from its fellows, however adhesive may be its alkaline and inky bond. A similar lever guards the exit 
 of each type from the wheel, and the hold is slackened only during the instant it presses fairly against 
 the steel mouth of a channel for its reception. Thirty lines are received at once in the wheel, and the 
 machine has been for several months in operation -without appearing to wear, or otherwise injure the 
 sides of the type. The nicks cause a slight annoyance by catching the rule in setting, but this evil will 
 probably be overcome by practice. Each machiue will distribute but one size of type ; but the inven- 
 tor states that they may be so constructed as to be easily adapted to the different sizes of small type. 
 If worked by hand, one man or boy can distribute 12,000 ems per hour, and with scarcely a possibility 
 of an error of a single type ; whereas by the usual process of hand distribution, 3,000 ems are about 
 the average. The machines can be worked by steam, and one man can then attend to three of them, 
 .making the total distribution in one hour 36,000 ems. 
 
VALVES, BALANCED. 
 
 780 
 
 URANIUM. A metal discovered by Klaproth in 1789. The oxides of uranium are used in painting 
 upon porcelain, yielding a fine orange color in the enamelling fire, and a black one in that in which the 
 porcelain itself is baked. 3096. 
 
 VALVES. (See Engines, Varieties and Details of.) 
 
 Cornell and Hosking's Treble Beat Hydraulic Values. 
 
 A is the valve seat; B, the valve; CO, the passages 
 through the seat, and D D, passages through and around 
 the valve ; E is the guard or stop to prevent the valve from 
 being thrown out of its seat by any sudden or unusual ac- 
 tion of the engine. In fig. 3G96 the valve is shown in its 
 open position, and the arrows indicate the course taken by 
 the water in passing through it ; a a, b b, c c, are the seats 
 or bearing surfaces. The most prominent advantage of- L 
 fered by these valves, is the larger opening for the passage 
 of the water than is afforded by the valves of the forms hitherto in use, while at the same time the lift 
 is reduced, and consequently the concussion very considerably lessened. 
 
 VALVES, BALANCED — Stevens’ Improvements, 1851. The patentee’s object is a convenient 
 adaptation to the double-acting steam-engines of balanced valves, commonly known as the Cornish 
 double-beat valves. For the balanced spindle valve, as commonly constructed, is liable to two objec- 
 
 tions : in the first place, the valve being formed by two disks connected by a spindle, the force of tho 
 steam acting against the disks in opposite directions puts a great strain on the spindle, so that should 
 it be slightly eccentric, the valve will be sprung from the seat and will leak ; and in the second place, 
 the difference of expansion between the valve spindle, which is completely surrounded by steam, and 
 
790 
 
 VALVES. BALANCED. 
 
 the steam-chests holding the valves, which is on the outside, exposed to the atmosphere, will also cause 
 the valves to leak. The valves commonly known as the Cornish double-beat valves are obviously 
 superior in principle to the spindle valves just described, and having been invented nearly a century 
 ago, and been in constant use ever since, it may be presumed that their general introduction in the 
 double-acting steam-engine, where balanced valves are used, has been prevented or retarded by the 
 difficulties presented for their adaptation to that purpose. These difficulties might be of the space 
 occupied, or of the expense, or of such an adaptation as would alter but little the arrangements of the 
 existing parts of the engine. The object is to endeavor to arrange these valves in such manner tha* 
 
 869a 
 
 itie advantages gained by their superiority in principle may not be so counterbalanced by the difficulties 
 above named, as to prevent their general introduction. To effect this, the valves are arranged on the 
 lame level, as this is the arrangement most generally adopted in engines having balanced valves ; and 
 for the same purpose certain peculiarities are introduced in the construction of the valve, that render it 
 different from any hitherto in use. 
 
 Fig. 3698 represents a side view of one of each of the steam and exhaust valves ; the steam-valve 
 being the Cornish valve, and the exhaust-valve having Stevens’ improvement. 
 
 Fig. 3699 represents a vertical section of the same valves both raised off their seats, which are alse 
 shown in section. 
 
 Fig, 3700 represents a horizontal view of the same valves. 
 
VALVES, BALANCED. 
 
 791 
 
 Fig 3C97 represents a vertical section of the side-pipes, steam-chests, valves, and valve-seats. 
 
 Fig. 3701 represents a horizontal cross-section of the lower steam-chest valves and valve-seats, taken 
 through the dotted line xx of Fig. 3697. 
 
 Fig. 3702 represents a horizontal view of the lower steam-chest. 
 
 Fig. 3703 represents a vertical section of the side-pipes, taken through the dotted line yy of Fig. 4082 
 
 In the drawings, a is the lower steam-chest; b is the upper steam-chest,; c and c are the side-pipes, 
 leading respectively to the boiler and condenser ; d and d are the openings from the side-pipes into the 
 cylinder nozzles; e is the opening into the condenser. 
 
 h h represents the two steam-valves, differing but little, if any, from the Cornish valve ; m and m 
 represents the two exhaust-valves, showing the alterations made to adapt them to the position in which 
 they are placed relatively to the steam-passages. In the first place we will describe the different parts 
 of the Cornish valve. 
 
 /and/ are respectively the lower and upper seats, the upper seat being formed on the circumference 
 of a disk supported by a cross ; g g, cast in the centre of the ring, forming the lower seat; the valve h 
 is formed by a hollow cylinder, the lower part of which being turned in, as shown, forms the valve- 
 face i ; that rests on the seat / and the upper part also turned in, forms the valve-face i ; that rests on 
 the seat/; k k are ribs cast on the inside of the valve to guide it ; l is a cross by which the valve is 
 lifted by the valve-stem. 
 
 The steam-valve h, thus drawn and described, does not differ materially, if in any respect, from a 
 Cornish double-beat valve ; and we have been thus particular in describing it in order to explain the 
 manner in which to alter it, the alteration constituting the material part of the invention. 
 
 It will be observed by a reference to the drawings that the position of the exhaust-valve with respect 
 to the steam-passages, and also with regard to the direction in which it is opened, is such that if it were 
 made similar to the valve just described, the pressure of the steam would force it from its seat. It is 
 necessary, therefore, in order that the valve shall be retained on its seat by the pressure of the steam, 
 that the seat formed on the disk supported by the ribs shall be larger in diameter than the seat that 
 forms the circular opening through which the steam passes. In order to effect this, a ring is attached 
 to the valve, forming the bearing for the smaller seat, this ring being smaller in diameter than the disk ; 
 there is also a ring attached to this disk, forming the larger seat. We are thus enabled to put the valve 
 together by slipping the smaller ring over the disk, and then by attaching the larger ring to the disk, 
 and finally by slipping the valve over the disk and attaching it to the smaller ring. 
 
 The faces of this valve having respectively the smaller and larger diameter are represented respect- 
 ively by n and n, resting on the seats o and o' ; p is the disk supported by the cross q. The valve is 
 formed in two pieces by bolting it to the ring r, on the edge of which the smaller valve-face n is shown ; 
 the disk is also formed into two pieces, by bolting to the disk p the ring s, on the edge of which the 
 larger valve-seat o' is shown. To put the valve in its place, the ring r must be slipped over the disk p. 
 then the ring s must be bolted to the disk p, and finally the remainder of the valve must be slipped 
 over the disk p and ring s, and bolted to the ring r ; u is a cross by which the valve is lifted by the 
 valve-stem, 1 1 are ribs to guide the valve. From the position in which this valve m is shown in refer- 
 ence to the steam-passages, it will be seen that when the valve is closed the pressure of steam will be 
 below the valve, and the vacuum will be above the valve ; it will also be seen from the construction ol 
 the valve that it will be held down on its seat by the pressure of the steam acting from below. 
 
 VELOCIMETER. An apparatus for measuring the rate of speed of machinery. When the velocity 
 is unifonn, the instrument is merely a measurer of distance ; but this is not the case with a variable 
 velocity, which requires a much more elaborate contrivance for its estimation. Such a velocity meas- 
 urer was constructed by Breguet, of Paris, under the direction of M. Morin, the principle of which may- 
 be briefly explained as follows : A circular disc, covered with card or paper, is made to revolve with an 
 uniform motion by means of clock-work, regulated by air-vanes : upon this disc a revolving pencil, 
 whose motion is caused by and corresponds with that of the body whose vai-iable velocity is to be meas- 
 ured, describes a curved line ; and from this curve, which results from a combination of the variable 
 with the uniform motion, the velocity may be easily ascertained by processes and formulae adapted to 
 the purpose. 
 
 VELOCITY, VIRTUAL. Virtual velocity, in mechanics, is the velocity which a body in equilibrium 
 would actually acquire during the first instant of its motion in case of the equilibrium being disturbed. 
 
 The general principles on which the laws of equilibrium in machines are established may be reduced 
 to three ; namely, the principle of the lever, the principle of the composition of forces, and the principle 
 of virtual velocities. The last consists in this, that forces are in equilibrium when they are in the inverse 
 ratio of the virtual velocities of the points to which they are applied, estimated in the direction ip which 
 
792 
 
 VERNIER, 
 
 they respectively act. Thus, let F and F' be two forces applied to the points p and p' of a body which 
 is in equilibrium between their joint actions, and let s and s' be the spaces which the points p and p 1 
 would describe in the first instant of time, in case of the equilibrium being disturbed ; then F : F' : : s' : », 
 or Fs = F' s'. The principle is thus enunciated generally by Lagrange, ( Mcc . Analytique, p. 22 :) 
 
 “ If any system of bodies or material points, urged each by any forces whatever, be in equilibrium, 
 and there be given to the system any small motion, by virtue of which each point describes an infinitely 
 small space, which space will represent the virtual velocity of the point; then the sum of the forces, 
 multiplied each by the space w r hich the point to which it is applied describes in the direction of that 
 force, will be always equal to zero or nothing, regarding as positive the small spaces described in the 
 direction of the forces, and as negative those described in the opposite direction.” 
 
 In order to illustrate this principle we may take as an example the case of the bent lever, Fig. 3700. 
 Let P P' P" be the points of application of the three forces F F' F", acting on the lever B A C, in the 
 directions P Q, P' Q', P" Q", which are all supposed to be comprised in the same plane. Suppose the 
 lever to describe an infinitely small angle about the fulcrum 
 A, so that the points P P' P" come into the positions pp' p". 
 
 According to the definition given above, the infinitely small 
 arcs P p, P' pi', P " p", which may be considered as straight 
 lines, will be the virtual velocities of the points of applica- 
 tion P P' P", of the three forces F F' F". From the points 
 pp' p” let there be drawn p m, p' m‘, p" in", respectively 
 perpendicular to the lines P Q, P' Q', P" Q" ; then P m will 
 be the virtual velocity of the point P reduced to the direc- 
 tion P Q of the force F, and P' m\ P" m" will in like man- 
 ner represent the virtual velocities of the points P' and P" 
 reduced to the directions in which the forces F' and F" respectively act. Let P m = s, I" in' = s', and 
 P" in" — s" ; and as the force F acting in the direction P Q tends to turn the lever in the direction in 
 which the motion has been supposed to take place, while F' and F" tend to turn it in the contrary di- 
 rection, the space s must be regarded as positive, and s' and s" as negative. 
 
 Now, according to the principle of virtual velocities the sum of the given forces, each multiplied by 
 the velocity of its point of application reduced to the direction of that force, is zero in the case of equili- 
 brium ; and, reciprocally, when this sum is zero the system is in equilibrium ; hence the equation of the 
 equilibrium of the lever is 
 
 F s F' s' + F" s" — 0. 
 
 It is easy to verify this equation by showing that it may be derived from the equation of equilibrium 
 deduced from the principle of the lever. From A let A q, A q‘, A q", be drawn respectively perpen- 
 dicular to the directions P Q, P' Q', P" Q", and let the angle P A p = 8 ; then, since the angle A Pp 
 may be regarded as a right angle, m P p = P A q ; whence the two triangles m Pp, q A P, are similar, 
 arid m P : A q : : Pp : P A : : tan. 8 : 1 ; therefore m P = A q tan. 6, that is, s — A q tan. $. In like man- 
 ner we have s' — A q’ tan. 6, s' — A q" tan. 8 ; whence, by substituting in the above equation, and leav- 
 ing out the common multiplier tan. 8, w^e find 
 
 F • A q -|- F 1 • A q' + F" • A q" = 0, 
 which is the well-known equation of equilibrium. 
 
 The equation F s -f- F' s' -f- F" s" = 0 may be extended to a solid body of any form, or to any machine 
 whatever. Let dm be an element of the body, F an accelerating force applied to dm, v the velocity of 
 that element, z the angle comprised between the direction of the force F and that in which the element 
 d in moves ; then the moving force of the element will be F dm, and v cos. z, its velocity estimated in 
 the direction of this force ; and consequently, by the principle of virtual velocities, the equation of equi- 
 librium will be J ' F v cos . zdm — 0. 
 
 The principle of virtual velocities is easily verified by experiment with respect to all the simple ma- 
 chines; namely, the lever, the pulley, the w'heel and axle, the inclined plane, and the screw. Its im- 
 portance as a fundamental principle in rational mechanics was first recognized by John Bernoulli, (see 
 the Nouvelle Mecanique of Varignon, tom. ii. ;) and Lagrange has derived from it the whole theories of 
 statics and dynamics in his celebrated work, the Mecanique Analytique. Fourier ( Journal de V Ecole 
 Polytechnique, cahier v.) has demonstrated the principle from the property of the lever. 
 
 VENTILATION. See Warming. 
 
 VERNIER. A contrivance for measuring intervals between the divisions of graduated scales or cir- 
 cular instruments. The name is given from that of the inventor, Peter Vernier, who published an 
 account of the contrivance in a work printed at Brussels in 1631. It consists of a small movable scale, 
 which slides along the graduated scale ; the divisions on the one scale beiifg to those on the other .u 
 the proportion of two numbers which differ from each other by unity. The theory of the instrument, 
 and the manner in which it is used, may be explained as follows : 
 
 3700 . 
 
 B | 
 
 
 1 A 
 
 2 1 | 
 
 987654321 
 
 9 8 
 
 ?.’ l i ! i \ I I I I I I ir 
 10 9876543210 
 
 Let AE = (i be a distance on tlie scale containing n of its divisions. Let vv be another scale equa. 
 in length to n — 1 of the divisions oil AB; and let v v be divided into n equal parts. Since the distance 
 
VERNIER. 
 
 793 
 
 A B — o, and contains n equal parts, each division on the scale — — . Hence the length of the vetniet 
 
 vv=-a — — ; and, as it is divided into n equal parts, each division on the vernier = — («-I) 
 
 = — — — „ ; and therefore the difference between a division on the scale and one on the vernier . 
 
 n n n 
 
 Suppose the zero of the vernier to coincide with the division marked A on the scale ; then the first di- 
 vision on the vernier will not coincide with the first after A on the scale, but fall behind it by a quantity 
 
 equal to their difference, or equal to In like manner, the next line on the vernier will fall behind 
 
 the next on the scale by a quantity equal to twice the difference of the divisions, or equal to ■ 
 
 The 
 
 3 a 
 
 third on the vernier will fall behind the third on the scale by — ; and so on to the nth division on the 
 
 vernier, which will fall behind the nth on the scale by — - — — , that is, by a whole division ; and there- 
 
 J n 2 n J 
 
 fore the nth on the vernier coincides with the division n — 1 on the scale. Conceive the scale to be a 
 
 scale of inches, and suppose it divided into tenths ; then a = 1 inch, n — 10, — — -L of an in., and (the 
 
 • n 1 u n 
 
 difference between a division on the scale and on the vernier) = T i F ; so that the yi^th of an inch is 
 exhibited on the scale, though its divisions are only to tenths. 
 
 The vernier is connected with the scale in such a way that it can be moved along it by means of a 
 rack and pinion, or a tangent-screw, or some similar contrivance, and its zero be brought to coincide with 
 any point on the scale. If, when the vernier is thus adjusted, its zero coincides exactly with a division 
 on the scale, the measure is read off at once ; but if (as must generally happen, the zero falls between 
 two of the divisions on the scale, then some one of the lines on the vernier will coincide, or very nearly 
 coincide, with one of the divisions on the scale, and the distance of the zero beyond the last division on 
 the scale behind it is expressed in hundredths by the number of the division on the vernier which is co- 
 incident with a division on the scale. Suppose, for example, the position of the vernier with respect to 
 the scale be as represented in Fig. 3701 , where the zero of the vernier is brought to coincide with a cer • 
 
 1234501891 123 
 
 rm p \ s i tt imi 
 
 i i r i r i i r i . i 
 
 0 123456789 10 
 
 □J 
 
 tain point p on the scale. The poiptp is read on the scale 29 inches, 2-10ths, and a fraction, which is 
 to be measured by the vernier. Here the division 6 on the vernier coincides with that which is marked 
 7 on the scale ; therefore the distance of the zero of the vernier from the last division (2) behind it on 
 the scale is 5-lOOths of an inch; for as 5 on the vernier coincides with 7 on the scale, the distance of 4 
 from 6 is l-100ths ; of 3 from 5, 2-100ths ; of 2 from 4, 3-100ths ; of 1 from 3, 4-100ths ; and of 0 from 2, 
 5-100ths. In like manner, if the vernier were pushed along till the division 8 coincided with 30 inches 
 on the scale, then the reading of the zero point would be 29 inches, 2-10ths, and 8-100ths. If, when the 
 zero is brought to coincide with p, none of the divisions on the vernier coincide exactly with a division 
 on the scale ; for example, if the 5 on the vernier should be a little past the 7 on the scale, and the 6 not 
 up to the 8, the reading would be between 5-100ths and 6-100ths ; but its precise amount could only be 
 stated by estimation. If the line 5 appeared nearer 7 than 6 to 8 lie distance measured would be 
 greater than 5-100ths, or 10-200ths, but less than ll-200ths ; and if the line 6 appeared nearer to 8 than 
 5 to 7, the distance would be greater than ll-200ths, but less than 12-200ths, or 6-100ths. Thus in any 
 case the limits of the uncertainty must be confined within a distance = l-200ths of an inch. In order that 
 the coincidences may be observed with greater certainty, the divisions are generally read with a lens. 
 
 The vernier is equally applicable to circular scales as astronomical circles ; it is then circular also, 
 and must move concentric with the limb of the circle. Suppose the limb divided into intervals of 10' ; 
 and let n = 10. We have then 10 divisions on the limb = 100 , =a; and the length of the vernier 
 
 — -^ = 100' — 10' = 90'; which, divided into 10 equal parts, gives 9' for the length of a divi- 
 sion on the vernier, and consequently the difference of the length of a division on the scale and on the 
 vernier =1'. The arc, therefore, can be read to minutes. But the reading may be carried to much 
 more minute quantities by increasing the length and the number of divisions on the vernier. Instead of 
 embracing 9 intervals of 10' on the scale, let the vernier embrace 59 such intervals, and be divided into 
 
 60 equal parts. We have then a = 10' X 60 = 600', n = 60, n 2 = 3600 ; therefore, - = — — - — -- = 
 
 ’ ’ n 2 3600 6 
 
 10"; that is to say, the arc may be read to 10". 
 
 In barometers, where a considerable degree of accuracy is required, the inch is divided into 20 equal 
 parts ; the vernier is made equal in length to 24 of these, and divided into 25 equal parts. In this case 
 
 25 
 
 we have a — — = T25 inch, n — 25 ; 
 20 
 
 ing to l-500th of an inch. 
 
 therefore 
 
 a 
 n 1 
 
 1-25 
 
 = 0’002 ; so that the vernier gives the read 
 
 625 
 
794 
 
 WARMING AND VENTILATION. 
 
 Instead of making the vernier equal to n — 1 divisions of the scale, it is sometimes made equal tc 
 n ~f- 1 divisions, and the object will still be accomplished in precisely the same manner. For in this 
 
 case the length of a division on the scale being as before, — , and that of a division on the vernier - 
 
 n n 
 
 ( a -\ — } = — 4-— „, the difference is still The principle is the same in both cases. 
 nr n ra 2 n 2 1 
 
 The vernier is often called a nonius, but improperly, the contrivance invented by Nonius or Nunnez 
 being on a quite different principle. 
 
 VICE, LEVER. This is an engraving of a vice invented by Mr. J. Peck, and improved by Mr. L. 
 Pardee, of New Haven, Conn. It possesses great strength and great power. It is made of wrought- 
 iron, and is claimed to have better qualities than any now in use. It is w'orked entirely by the foot 
 without laying down a tool for that purpose, and it can be changed to receive work from l-16th to 8 or 
 10 inches in width, as quickly as any other vice can be moved one-fourth of an inch. 
 
 3702. 
 
 Description. — a t Fig. 3102, sliding-jaw; b, jointed or swing jaw; c, rail on which the sliding-jaw 
 moves ; d, click which catches in ratchet on rail c, and holds the sliding-jaw firmly where placed. E 
 jointed lever (elbow-joint) w'hicli turns on pins ee, and is attached to prong of rail c and the lower end 
 of the swinging-jaw. g, foot-lever w 7 ith joint attached to leg of bench, and connected by rod i with 
 jointed lever, h, click which catches in ratchet at the foot of the forward bench-leg, and holds the jaws 
 firmly as forced up by the combined levers ; it is easily tripped with the foot. / is a spiral spring which 
 lifts the foot-lever and throws open the jaw. 
 
 It will be recollected that when this vice is forced up it becomes very firmly attached to the bench, 
 and very solid for chipping and other heavy work that is required to be put into a vice, and heavy work 
 requiring both hands to lift can be very easily placed in it. It is certainly much easier for the mechanic, 
 for the strain upon the breast in turning the screw is avoided. This vice has been tested and found to 
 be a useful invention, and one of them weighing fifty pounds has been found to possess as much power 
 as an English vice weighing seventy pounds. 
 
 WARMING AND VENTILATION. Heat is given off from bodies by two distinct processes — ra- 
 diation and conduction. In radiation, rays of heat diverge in straight lines from every part of a heated 
 surface, and also from extremely minute depths below such surface. These rays, like rays of light, are 
 subject to the laws of refraction and reflection, and their intensity decreases as the square of the distance. 
 When we approach an open fire, or the surface of a stove, we feel its heat by radiation, and it has been 
 ascertained that, at the ordinary temperature of hot-water pipes, about one-fourth of the total cooling 
 effect is due to radiation. 
 
 But the amount of radiation of a body heated above the temperature of he surrounding atmosphere 
 depends greatly upon the nature of its surface. If a vessel of hot water, coated with lamp-black, radiate 
 100 parts of heat within a given time, a similar vessel, containing water of the same temperature, coated 
 with writing-paper, will radiate 98 parts of heat ; resin, 96 ; China ink, 88 ; red lead, or isinglass, 80 ; 
 plumbago, 15; tarnished lead, 45; tin, scratched wfith sand-paper, 22; mercury, 20; clean lead, 19; 
 polished iron, 15 ; tin-plate, 12. 
 
 In order to ascertain the velocity of cooling from a surface of a cast-iron pipe 30 inches long, 21 
 inches diameter internally, and 3 inches diameter externally, the rates of cooling were tried with differ- 
 ent states of the surface : first, when covered with the usual brown surface of protoxide of iron ; next it 
 was varnished black, and finally the varnish was scraped off, and the pipe painted white with two coats 
 of lead paint. The ratios of coding 1° were found to be for the black varnished surface 1'21 minutes - 
 
WARMING AND VENTILATION. 
 
 79 ; 
 
 for the iron surface, l'2o minutes, and for the white painted surface, T28 minutes. “ These ratios are in 
 the proportion of 100, 103 - 3, and 105’7 ; but, as the relative heating effect is the inverse of the time of 
 cooling, we shall find that 100 feet of varnished pipe, 1031 feet of plain iron pipe, or 105J feet of iron 
 pipe, painted white, will each produce an equal effect.” 
 
 Tarnished surfaces, or such as are roughened by emery, by the file, or by drawing streaks or lines 
 with a graving tool, have their radiating power considerably increased. But, according to Melloni, the 
 roughness of the surface merely acts by altering the superficial density which varies according as the 
 body is of a greater or less density, previous to the alteration of its surface by roughening. The follow- 
 ing experiment gives the data for this conclusion : Melloni took four plates of. silver, two of which, when 
 cast, were left in their natural state, without hammering, and the other two were planished to a high 
 degree under the hammer. All four plates were then finely polished with pumice-stone and charcoal, 
 and after this one of each of the pairs of plates was roughened by rubbing with coarse emery paper in 
 one direction. The quantity of heat radiated from these plates was as follows : 
 
 Hammered and polished plate 10° I Cast and polished plate 13*T° 
 
 Hammered and roughened plate 18° | Cast and roughened plate 1T3° 
 
 Thus it appears that the hard hammered plate was increased in radiating power four-fifths by roughen- 
 ing its surface, while the soft cast plate lost nearly one-fifth of its power by the same process. 
 
 When a body is exposed to a source of heat, a portion of it is absorbed, and it has been proved, ex 
 perimentally, that the absorptive power of bodies for heat is precisely equal to their radiative power. 
 It was long supposed that color had great influence on radiation and absorption. By exposing variously 
 colored surfaces to the heat of the sun, their absorbing power was in the following order : black, blue, 
 green, red, yellow, and white. Hence it would naturally be expected that the radiating powers of dif- 
 ferently colored bodies would be in this order, and that by painting a body of a dark color we should 
 increase its radiating power. Such, however, is not the case, for the absorption and radiation of simpli 
 heat , or heat without light, depend on the nature of the surface rather than on color. 
 
 The numbers which represent the radiating powers of different bodies for invisible or non-luminous 
 heat, or heat of low temperature, evidently bear no relation to color, for lamp-black and writing-paper 
 are nearly equal ; Indian ink is much less, and plumbago still less. A thermometer bulb, coated with 
 a paste of chalk, is affected by invisible heat even more than a similar one coated with Indian ink ; but, 
 this result does not occur when the heat is from a luminous source. Thus it was found that when two 
 spirit thermometers, one containing colored, and the other colorless alcohol, were exposed to the sun, 
 the colorwl liquid rose much more rapidly than the colorless, but when they were both plunged into a 
 vessel containing hot water, they rose equally in equal times. 
 
 The propagation of heat by conduction is a very different process from that of radiation. By conduc- 
 tion, the heat travels through or among the particles of solid matter, until the temperature of the body 
 in contact with the source of heat is raised more or less above the temperature of the air. When heat, 
 is communicated to a fluid body, the process is different. In consequence of the great mobility of its 
 particles, those which first come under the action of the source of heat, being raised in temperature, es- 
 cape from its influence, and ascend through the fluid mass, distributing a portion of their acquired heat 
 among other particles on its way ; other particles immediately take its place, and being heated, ascend 
 in like manner and distribute their heat. By this process of convection, as it is called, the whole of the 
 particles in a confined mass of fluid come under the action of the heating body ; those first heated es- 
 cape as far as possible from the source cf heat, and becoming cooled, descend again to be heated, and 
 again to ascend and descend. In this w'ay a circulation is maintained in the whole mass of fluid. 
 
 It is only by this process of convection that air may be said to be a conducting body, for if a mass of 
 air be confined in such a way as to prevent the free motion of its particles, it ceases almost entirely to 
 conduct heat, and may be usefully employed to retain heat ; as in the case of double windows, the 
 inclosed mass of air prevents the heat from escaping from the apartment, and shields the glass which is 
 in contact with the warm air of the room from the cooling action of the external air. According to some 
 experiments each square foot of glass will cool 1 ‘27 9 cubic feet of air 1° per minute, when the temper- 
 ature of the glass is 1° above that of the external air. This, however, is in a still atmosphere. Glass 
 is a very bad conductor of heat, and the cooling effect of wind upon it is not so great as is generally 
 supposed. 
 
 Solids differ greatly in their heat-conducting powers. If gold conduct 100 parts of heat, platina will 
 conduct 98T0 parts; silver, 97‘30; copper, 89'82; iron, 3743; zinc, 36'30 ; tin, 30‘39 ; lead, 17'96; 
 marble, 23'60 ; porcelain, 1‘2'20 ; fire-brick, 1T40. The slow conducting power of such bodies as porce- 
 lain, brick, and glass, may be contrasted with the rapid conducting power of some of the metals by 
 holding one end of a piece of each substance in a flame ; the metal will soon become too hot for the 
 hand, while the porcelain may be heated to redness in the flame without its being felt to be much 
 warmer at the other end. A joractical application of this property is also to be found in the materials 
 of close stoves for heating apartments ; for while those in which the outer case consists of copper or 
 iron receive their heat quickly and part with it quickly, those which are lined with brick and covered 
 with porcelain receive their heat slowly, and communicate it slowly to the air of the apartment. Much, 
 however, depends on the thickness of the metal casing ; for, by increasing this, it will, of course, retain 
 its heat longer. 
 
 When a heated body cools under ordinary circumstances, it is by the united effects of radiation and 
 conduction, and the rate of cooling increases considerably in proportion as the temperature of the heated 
 body is greater than that of the surrounding medium. We have seen that the cooling effect of radia- 
 tion depends greatly on the nature of the surface ; but it is a remarkable fact, that the cooling effect of 
 the air by conduction has no reference to the nature of the surface ; it is the same on all substances, 
 and in all states of the surface of those substances. The air in contact with such surfaces robs them of 
 ft portion of heat, and immediately ascends to make way for other portions of air, which repeat the 
 
796 
 
 WARMING AND VENTILATION. 
 
 process. By these two processes the body cools down to the temperature of the surrounding air, the 
 conductive power of which varies with its elasticity, or barometric pressure; the greater the pressure 
 the greater also the cooling power. It has also been shown by Dulong and Petit that the ratio of heat 
 lost by contact of the air alone, is constant at all temperatures ; that is, whatever is the ratio between 
 40° and 80° is also the ratio between 80° and 160°, or between 100° and 200°. 
 
 It was long supposed that a certain relation existed between the radiating and conducting powers of 
 heated bodies. This does, to a certain extent, apply where low temperatures are concerned, but does 
 not hold at high temperatures. Thus, in a set of experiments by Dmong and Petit, the total cooling at 
 60° . and 120° (Centigrade) was found to be about as 3 to 7 ; at 60° and 180°, as 3 to 13; and at 60° 
 and 240°, as 3 to 21 ; whereas, according to the old theory, these numbers would have been as 3 to 0, 
 3 to 9, and 3 to 12. When the excess of temperature of the heated body above the surrounding air is 
 as high as 240° Cent., or 432° Fahr., the real velocity of cooling is nearly double what it would have 
 been by the old theory, varying, however, with the surface. 
 
 Since the heat lost by contact of the air is the same for all bodies, while those which radiate most, or 
 are the worst conductors, give out more heat in the same time than those bodies which radiate least, or 
 are good conductors, it might be supposed that those metals which are the worst conductors would be 
 best adapted for vessels or pipes for warming rooms by radiation. “ Such would be the case if the 
 vessels were infinitely thin ; but as this is not possible, the slow conducting power of the metal (iron) 
 opposes an insuperable obstacle to the rapid cooling of any liquid contained within it, by preventing 
 the exterior surface from reaching so high a temperature as would that of a more perfectly conducting 
 metal under similar circumstances; thus preventing the loss of heat both by contact of the air and by 
 radiation, the effect of both being proportional to ■‘Tie excess of heat of the exterior surface of the heated 
 body. If a leaden vessel were infinitely thin, the liquid contained in it would cool sooner than in a 
 similar vessel of copper, brass, or iron ; but the greater the thickness of the metal, the more apparent 
 becomes the deviation from this rule ; and as the vessels for containing water must always have some 
 considerable thickness, those metals which are the worst conductors will oppose the greatest resistance 
 to the cooling of the contained liquid.” 
 
 The reflective power of different substances for heat is inversely as their radiating power. If a sur- 
 face of brass reflect 100 parts of heat, a similar surface of silver will reflect 90 parts ; tin-foil, 85 ; block- 
 tin, 80 ; steel, 70 ; lead, 60 ; tin-foil, softened by mercury, 10 ; glass, 10 ; glass, coated with wax, 5. 
 
 When similar substances are exposed to the same temperature they all become heated to the same 
 degree, as measured by the thermometer ; but if the temperatures of dissimilar substances have to be 
 raised to the same degree, the quantities of heat required for the purpose will be very different for dif- 
 ferent substances. Thus, if we place side by side, upon a hot plate, two equal and similar vessels, one 
 containing a certain weight of water, and the other an equal weight of mercury, the mercury will soon 
 become much hotter than the water. So also, on lowering the temperature of dissimilar substances to 
 an equal degree, some will give out more and others less heat. Different bodies, therefore, display dif- 
 ferent degrees of susceptibility for receiving free heat within their molecules ; this is called their capa- 
 city for heat, and the quantity required to raise equal masses or equal weights 1°, is termed their spe- 
 cific heat. The theory of specific heat is of great importance in a practical point of view, for on it de- 
 pend many of the calculations for ascertaining the proportions of the various kinds of apparatus em- 
 ployed in warming buildings. 
 
 The specific heat of different substances can be ascertained by mixing together, with certain precau- 
 tions, ascertained quantities of the substances under consideration, when their mutual capacities for heat 
 are determined by the decrease in the temperature of the hotter body, and by its increase in the cooler. 
 Thus, if 1 lb. of mercury at 32°, and 1 lb. of water at 62°, be mixed together, the common temperature 
 will be 61°. The temperature of the metal has, therefore, risen 30°, while that of the water has fallen 
 1°. If the mercury had been at 02°, and the water at 32°, the common temperature of the mixture 
 would have been 33°. In this case the water would have gained 1° of temperature, and the mercury 
 would have lost 30°. Thus it appears that the capacity of water for heat exceeds that of mercury 30 
 times. If the water be taken as unity, the specific heat of the mercury will be -Jj, or 0'033. 
 
 Again, if 1 lb. of iron filings at 6S° be mixed with 1 lb. of water at 32°, the temperature of the mix- 
 ture will be 36°. That quantity of heat, therefore, the loss of which lowers the temperature of iron 
 32°, raises the temperature of water only 4° ; so that eight times as much heat is required to raise or 
 depress the temperature of the water 1°, as would raise or depress the temperature of an equal weight 
 of iron 1°. Hence the specific heat of iron is §, or 0T25. 
 
 The capacity of substances for heat may also be found by observing the quantity of ice which the 
 body under investigation is capable of thawing. Thus, if equal weights of iron and lead be operated 
 on, it will be found that the iron requires a greater quantity of heat than the lead to produce the same 
 change of temperature, in the proportion of nearly 1 1 to 3. If a bar of iron, in falling from 100° to 95°, 
 melt 11 grains of ice, then a bar of lead of equal weight, under similar circumstances, would melt rather 
 less than 3 grains ; heat is, therefore, more effective in warming lead than iron. Again, an ounce of 
 mercury and an ounce of water, in falling from 60° to 55°, will melt quantities of ice, in the proportion 
 of 33 to 1000, or very nearly 1 to 30 ; that is, to 'raise water from 55° to 60°, requires a greater quan- 
 tity of heat than to raise an equal weight of mercury through the same range of temperature, in the 
 proportion of 30 to 1. The quantity of ice melted by different kinds of fuel affords a convenient method 
 of estimating their relative values. Thus it has been found that 
 
 1 lb. of coal, of good quality 
 
 coke, “ “ 
 
 “ wood, “ “ 
 
 “ wood charcoal, “ 
 
 “ peat, “ “ 
 
 .melts 90 l’os. of ice. 
 . “ 84 
 
 . “ 32 
 
 “ 95 “ 
 
 . “ 19 
 
WARMING AND VENTILATION. 
 
 797 
 
 One method of estimating how much of the heat of a common fire is radiated around it, and how much 
 combines with the smoke, is to allow all the radiant heat to melt a quantity of ice contained in a ves- 
 sel surrounding the fire, and all the heat of the smoke to melt the ice in another vessel surrounding the 
 chimney. By comparing the two quantities of water thus obtained with the quantities of ice melted, 
 it will be found, according to Dr. Arnott, that the radiant portion of the heat is, in ordinary cases, rather 
 less than the combined, or less than half the whole heat produced. 
 
 The specific heat of bodies has been determinetLnot only for equal weights, but also for equal vol- 
 umes, and this is called their relative heat, which il*fo the specific heat of any substance directly as its 
 specific gravity. It may be found by multiplying the specific heat into the specific gravity ; and con- 
 versely, the specific heat may be found by dividing the relative heat by the specific gravity. Now as 
 the quantity of heat required to raise the temperature of 1 lb. of water 1° is sufficient to raise 1 lb. oi 
 mercury 30°, we say that the specific heat of mercury is - S ' (T , taking water as unity ; and since the spe- 
 cific gravity of mercury is about 13 6, it follows that the relative heat of an equal volume of this metal 
 is - 3 ~X 13'G=0'453. 
 
 With respect to gaseous bodies, it has been found that their specific heat is inversely as their specific 
 gravity or density ; and, consequently, equal weights of such gases contain a larger quantity of heat, 
 less their specific gravity. The capacity of atmospheric air is taken as the unit by which to estimate 
 the specific heat of gaseous bodies; but sometimes that of water is assumed as the unit, and then the 
 capacities of gases are comparable with those of solids and liquids. The latter values are obtained by 
 multiplying the former into 0"2669, which is the index of the specific heat of atmospheric air compared 
 with that of water. 
 
 The following table shows the specific heat of various substances referred to water as tire standard, 
 and are supposed to represent the quantity of heat contained n. equal weights of the several sub- 
 stances : 
 
 Water 1-0000 
 
 Aqueous vapor 0-8470 
 
 Alcohol OTOOO 
 
 Ether 06600 
 
 Oil 0-5200 
 
 Air 0-2669 
 
 Hydrogen 3’2936 
 
 Nitrogen 0'2754 
 
 Oxygen 0-2361 
 
 Carbonic acid 0-2210 
 
 Carbonic oxide 0-2S84 
 
 Charcoal 0'2631 
 
 Sulphur 0'1850 
 
 Wrought-iron 0-1100 
 
 Mercury 0-0330 
 
 Platinum 0-0314 
 
 Gold 0-0298 
 
 The method of ascertaining the specific heat of gases is as follows : — The gas to be examined is well 
 dried, and then brought from a vessel, surrounded with water at 212°, gradually through a spiral tube, 
 surrounded by cold water, the gas escaping through the opposite end of the spiral. In the course of its 
 passage, the gas parts with a portion of its heat to the cold water which surrounds the spiral, and the 
 temperature of the water gradually rises, until after some time it becomes stationary. The equilibrium 
 thus established between the water and the gas is measured by a thermometer, so as to find both the 
 rise in the temperature of the water, and the full in that of the gas. If the experiment be made with 
 some other gas, and the result should give a higher temperature to the water, then this second gas must 
 have imparted to the fluid a greater amount of heat than the former one did. If, on the contrary, the 
 temperature of water be less this time than before, it will have given out less heat, and the respective 
 capacities for heat of these two gases will be proportional to the temperatures of the water through 
 which they have been admitted. The capacity of atmospheric air being taken as the unit, the specific 
 heat of other gases may be expressed by proportionate numbers. To raise 1 lb. of water from 32° to 
 212°, requires the same quantity of heat as will raise 4 lbs. of atmospheric air the same number of de- 
 grees. The specific heat of air is therefore R or, more exactly, 0-2669 that of water, as stated in the 
 above table. 
 
 When heat is added to a solid body, the first effect which marks the increase of temperature is ex- 
 pansion. At a certain point, however, the temperature, as marked by the thermometer, becomes sta- 
 tionary ; and although the heat be continually applied, the temperature does not rise. The solid is 
 now undergoing a change of state ; it is passing from the solid into the liquid state ; and no rise in tem- 
 perature will be observed until the whole of the solid has become liquid. The point at which a body 
 begins to fuse or melt, is called its fusing point or point of liquefaction, and is different in different sub- 
 stances. The quantity of heat absorbed by the body, and unaccounted for, as far as the thermometer is 
 concerned, is called latent heat. When the body is liquefied, the temperature again begins to rise, until 
 another point is attained, when it again becomes stationary, and the liquid begins to pass off in the form 
 of vapor or steam. This point is called the boiling point, and is different in different substances. The 
 heat absorbed during the process of boiling or vaporization is also called latent. 
 
 In the following table, the melting points of a few substances are noted, together with the quantity of 
 heat rendered latent by each in passing from the solid into the liquid state. From these and other re- 
 sults, it may be seen that, in general, the higher the point of fusion, the greater will be the quantity of 
 heat absorbed in liquefaction. There is, however, no proportion between these effects, for ice and sper- 
 maceti melt at 32° and 112°, and yet the quantities of heat rendered latent are nearly the same. 
 
 Melting Point. Latent Heat. 
 
 W ator 32 degrees. 140 degrees 
 
 Sulphur 213 “ 143 7 “ 
 
 Spermaceti 112 “ 145 “ 
 
 Lead 612 “ 162 “ 
 
 Bees’-wax 150 “ 17o “ 
 
798 
 
 WARMING AND VENTILATION. 
 
 Melting Point. Latent Heat. 
 
 Zinc 773 degress. 493 degrees. 
 
 Tin 442 “ 500 
 
 Bismuth 476 “ 550 “ 
 
 In the following table, the boiling points of a few substances are given, together with the quantity of 
 heat rendered latent by each in passing from the lij^id into the aeriform state : 
 
 Water 
 
 Alcohol (sp. gr. 0'7947). 
 
 Ether 
 
 Oil of Turpentine 
 
 Nitric Acid (sp. gr. 1-50). 
 
 Ammonia 
 
 Vinegar 
 
 Petroleum 
 
 Boiling Point. Latent Heat. 
 
 .212 degrees. 1000 degrees. 
 
 .173 “ (bar. 29-5) 457 
 
 . 98 “ 312-9 “ 
 
 .314 “ 183-8 “ 
 
 .210 “ 550 
 
 865-9 “ 
 
 903 
 
 183-8 “ 
 
 These details respecting latent heat will enable the reader to compare the merits of the two systems 
 ol heating buildings by pipes filled with hot water, and by similar pipes filled with steam. 
 
 In the former system, it is not desirable to raise the water to the boiling point (212°), because, in 
 such case, steam would be formed, and this escaping by the safety-pipe, would abstract much useful 
 neat from the apparatus. In the latter system, it is desirable to maintain the pipes at 212°, because, 
 at a lower temperature, the steam would condense, and also absorb much useful heat from the appa- 
 ratus. From the necessity of maintaining the temperature of 212° in steam-pipes, it is evident that a 
 given length of steam-pipe will afford more heat than the same quantity of hot-water pipe ; but the fol- 
 lowing remarks by Mr. Hood, on the relative permanence of temperature of the two methods, will show 
 an advantage in favor of the hot-water system : 
 
 “ The weight of steam, at the temperature of 212°, compared with the weight of water at 212°, is 
 about as 1 to 1694 ; so that a pipe which is filled with water at 212° contains 1694 times as much mat- 
 ter as one of equal size filled with steam. If the source of heat be withdrawn from the steam-pipes, 
 the temperature will soon fall below 212°, and the steam immediately in contact with the pipes will 
 condense ; but in condensing, the steam parts with its latent heat ; and this heat, in passing from the 
 latent to the sensible state, will again raise the temperature of the pipes. But as soon as they are a 
 second time cooled down below 212°, a further portion of steam will condense, and a further quantity 
 of latent heat will pass into the state of heat of temperature ; and so on, until the whole quantity of 
 latent heat has been abstracted, and the whole of the steam condensed, in which state it will possess 
 just as much heating power as a similar bulk of water at the like temperature ; that is, the same as a 
 quantity of water occupying y-^Ly part of the space which the steam originally did. 
 
 “ The specific heat of uncondensed steam, compared with water, is for equal weights as -8470 to 1 ; 
 but the latent heat of steam being estimated at 1000°, we shall find that the relative heat obtainable 
 from equal weights of condensed steam and of water, reducing both from the temperature of 212° to 
 60°, to be as 7'425 to 1 ; but for equal bulks, it will be as 1 to 228, that is, bulk for bulk, water will 
 give out 228 times as much heat as steam, on reducing both from the temperature of 212° to 60°. A 
 given bulk of steam will, therefore, lose as much of its heat in one minute, as the same bulk of water 
 will lose in three hours and three quarters.” 
 
 But when the water and the steam are both contained in iron pipes of the same dimensions, the rate 
 of cooling will differ from this ratio, in consequence of the greater quantity of heat contained in the 
 metal than in the steam. The specific heat of iron being nearly the same as that of water, the pipe 
 filled with water will contain 4'68 times as much heat as that which is filled with steam; and if the 
 latter cools down to 60° in one hour, the other will require about four hours and a half to do the same. 
 There are other circumstances to be noticed hereafter, which cause the hot water apparatus to be six or 
 eight times (instead of 4J) more efficient as a source of warmth than steam. 
 
 The process of boiling is by no means indispensable to the formation and escape of steam or vapor ; 
 for at all temperatures below the boiling point, vapor is formed at the surface of liquids, and escapes 
 therefrom by a process called spontaneous evaporation. The difference between this process and ebul- 
 lition is chiefly this : — When a liquid boils, the vapor which escapes therefrom constantly maintains the 
 same temperature, provided the pressure remain the same ; but evaporation may go on at all tempera- 
 tures and pressures, the quantity of liquid evaporated depending on the temperature and the amount 
 of surface exposed. 
 
 We have seen that the pressure or elasticity of vapor at 212° is sufficient to support a column of 
 mercury 30 inches high. The force of vapor at lower temperatures is also measured by the length of 
 the mercurial column which it will support. Vapor at 200° will support 23'64 inches of mercury ; at 
 150°, 7-42 inches; at 100°, 1-86 inches; at 80°, 1 inch; at 60°, -524 inch; at 50°, -375 inch; at 32°, 
 •2 inch. 
 
 The amount of evaporation, however, is greatly influenced by the motion of the air, which carries off 
 the vapor from the surface of a liquid as fast as it is formed. A strong wind will cause twice as much 
 vapor to be discharged as a still atmosphere. Dalton ascertained the number of grains’ weight of water 
 evaporated per minute from a vessel, six inches in diameter, for all temperatures between 20° and 212°, 
 when the air was still, or in gentle or brisk motion. When the water was at 212°, the quantity evapo- 
 rated was 120 grains per minute in a still atmosphere ; 154 grains per minute with a gentle motion oi 
 the air ; and 189 grains per minute with a brisk motion of the air. The following is an extract from 
 his table between the temperatures of 40° and 60° : 
 
WARMING AND VENTILATION. 
 
 799 
 
 Temperature. 
 
 Force of vapor in 
 inches of mercury. 
 
 Evaporating force in grains of water. 
 
 Fahrenheit. 
 
 Still 
 
 Gentle. 
 
 Erislc. 
 
 40 degrees. 
 
 0'263 degrees. 
 
 T05 degrees. 
 
 T35 degrees. 
 
 T65 degrees. 
 
 42 
 
 ■283 
 
 T13 
 
 T45 
 
 T78 
 
 44 
 
 305 “ 
 
 1-22 
 
 T57 
 
 1-92 
 
 40 ‘ l 
 
 •327 
 
 T31 
 
 T68 
 
 2-00 
 
 48 
 
 •351 
 
 1-40 
 
 1-80 
 
 2-20 “ 
 
 50 
 
 •375 
 
 T50 
 
 T9 2 
 
 2-36 
 
 52 
 
 •401 
 
 TOO 
 
 2-06 “ 
 
 2-51 
 
 54 
 
 •429 
 
 1-71 
 
 2-20 “ 
 
 2-69 
 
 50 
 
 •458 
 
 T83 
 
 2-35 
 
 2-88 
 
 58 
 
 ■490 
 
 1-96 
 
 2-52 
 
 3-08 
 
 60 
 
 •524 
 
 2-10 
 
 2.70 
 
 3-30 
 
 The amount of spontaneous evaporation is also greatly influenced by the quantity of vapor already 
 existing in the air. In order to find this, we must ascertain the dew-point of the air, or the temperature 
 at which the vapor in the air begins to condense, and then, by referring to the table, the quantity of 
 vapor in the air at the time can be found ; and this, deducted from the quantity shown by the table to 
 be given off at the ascertained temperature of the evaporating liquid, will give the quantity of water 
 that will be evaporated per minute. In finding the dew-point, we must bring some colder body into 
 the air, or have the means of cooling some body to such a point as shall just condense the vapor of the 
 air upon its surface. Dr. Dalton used a very thin glass vessel, into which he poured cold water from a 
 well, or cooled down the water by adding a small portion of a freezing mixture. If the vapor was in- 
 stantly condensed, he poured out the cold water and used some a little warmer, and so on, until he 
 could just perceive a slight dew upon the surface. The temperature at which this took place was the 
 dew-point. In Daniell’s hygrometer, the cold is produced by the evaporation of ether. Now suppose 
 the dew-point of the air to be 40°, and the temperature of the air and of the evaporating liquid to be 
 60°, with a still atmosphere, the vapor in the air, as shown by the table at 40°, is 1'05 grains, which, 
 subtracted from that at 60°, or 210, gives To grains per minute as the quantity of vapor given off from 
 a surface six inches in diameter. 
 
 During the spontaneous evaporation of wet surfaces, a considerable degree of cold is produced by the 
 quantity of heat rendered latent by the formation of the vapor ; and the heat is mostly derived from the 
 liquid itself, or the surface containing it. By proper contrivances, water may be frozen, in consequence 
 of the abstraction of heat during the rapid formation of vapor. When a jJerson takes cold from wear- 
 ing wet clothes, the vapor from the wet clothes obtains its heat from his body, and the chilling sensa- 
 tion is often the greater the warmer the air. A person with damp clothes, entering a room filled with 
 hot dry air, is very likely to take cold, on account of the powerful effect of warm air in abstracting 
 moisture. 
 
 In a badly ventilated room, the moisture from the breath of the inmates, and from the combustion of 
 lamps and candles, accumulates nearly to the point of saturation. This is well shown by an experi- 
 ment of the late Professor Daniell. The temperature of a room being 45°, the dew-point was 39° ; a 
 fire was then lighted in it, the door and window shut, and no air was allowed to enter. The thermome- 
 ter rose to 55°, but the point of condensation remained the same. A party of eight persons afterwards 
 occupied the room for several hours, and the fire was kept up ; the temperature rose to 58°, and the 
 point of condensation rose to 52°. Now, if this room had been properly ventilated, the vapor would 
 have been removed as it was formed, and with it the effluvia and impure air. 
 
 On the warming of buildings by means of steam and hot water. — The method of warming build 
 ings by steam, depends on the rapid condensation of steam into water when admitted into any vessel 
 which is not so hot as itself. At the moment of condensation, the latent heat of the steam is given out 
 to the vessel containing it, and this diffuses the heat into the surrounding space. 
 
 The first practical application of this principle was made by James Watt, in the winter of 1184-5, 
 who fitted up an apparatus for warming his study. The room was 18 feet long, 14 feet wide, and 8£ 
 feet high. The apparatus consisted of a box, or heater, made of two side plates of tinned iron, about 3-J 
 feet long, by 2-J- feet wide, separated about an inch by stays, and jointed round the edges by tin-plate. 
 This heater was placed on its edge, near the floor of the room. It was furnished with a cock to let out 
 the air, and was supplied with steam by a pipe from a boiler, entering at its lower edge ; and by this 
 pipe the condensed water also returned to the boiler. The heating effect of this apparatus was not so 
 great as was anticipated, in consequence, perhaps, of the bright metallic surfaces of the box not being 
 favorable to radiation. 
 
 About the end of the year 1199, Mr. Lee, of Manchester, under the direction of Boulton and Watt, 
 erected a heating apparatus of cast-iron pipes, which served also as supports to the floor. This an- 
 swered perfectly, and was, in point of materials and construction, the earliest of its kind. Mr. Lee af- 
 terwards had his house heated by steam ; and the staircase, hall, and passages were warmed by the 
 apparatus shown in Fig. 3703. It was placed in the underground story, and consisted of a vertical cast- 
 iron cylinder a, surrounded by a casing of brick-work, leaving a space e e of two and a half inches all 
 round, and having openings i below, to admit the air. This casing was surrounded, at the distance 
 of three or four inches, by another wall, forming a sort of well c. The colder and heavier air falling to 
 the bottom of this well, entered by the holes i into the space e where it came in contact with the 
 cylinder a, and, being heated, ascended. The entrance of the steam into the cylinder was regulated by a 
 ralve, the air being allowed to escape by a stop-cock, while the steam was entering; the condensed 
 
800 
 
 WARMING AND VENTILATION. 
 
 water escaping by a pipe not shown in the figure. The transmission of the heated air was regulated 
 by a valve at a, on the top of the brick-work. This apparatus was so effective, and heated the staircase 
 to such a degree, that after it had been in operation a short time, it was 
 necessary to suspend its action by closing the valve at a, or by closing the 
 valve which admitted steam into the cylinder. 
 
 In establishments where a steam-engine is in daily use, the ^team-pipes 
 may be supplied from the engine-boiler, its dimensions being enlarged at the 
 rate of one cubic foot for every 2000 cubic feet of space, to be heated to the 
 temperature of 70° or 80°. A boiler adapted to an engine of one-horse 
 power is sufficient for heating 50,000 cubic feet of space. Hence an appa- 
 ratus specially erected for the purpose need not be of very large size, nor is 
 the quantity of fuel consumed great. If the fire under a small boiler be 
 carefully managed, 14 lbs. of coal will convert one cubic foot of water, at 50°, 
 into 1800 cubic feet of steam, at 216° ; and only 12 lbs. of coal are required 
 to convert the same quantity of water into steam, at 212°. The shape of the 
 boiler, and the method of setting it, must also be considered, and the furnace 
 must be arranged so as to admit no more air than is required to support the 
 combustion. The hot air must also be kept in contact with the sides of the 
 boiler, until as much of the heat as possible be abstracted from it. In such 
 an arrangement, according to Dr. Arnott, nearly half of all the heat produced 
 in the combustion is applied to use. 
 
 In estimating the extent of surface of steam-pipe required to raise the rooms to the proper tempera- 
 ture, it is necessary to consider how the heat is expended. This is done in three ways : — 1, Through the 
 thin glass of the windows. 2, More slowly through the walls, floors, and ceiling; and 3, In combination 
 with the air which escapes at the joinings of the windows and doors, or through openings expressly 
 made for the purpose of ventilation. The amount of heat lost in this way has been variously estimated 
 by different writers ; but Dr. Arnott states it thus : — That in a winter day, with the external tempera- 
 ture at 10° below freezing, to maintain in an ordinary apartment the agreeable and healthful tempera- 
 ture of G0 C , there must be of surface of steam-pipe, or other steam vessel heated to 200°, (which is the 
 average surface-temperature of vessels filled with steam of 212°,) about one foot square for every six 
 feet of single glass window of usual thickness ; as much for every 120 feet of wall, roof, and ceiling of 
 ordinary material and thickness ; and as much for every six cubic feet of hot air escaping per minute as 
 ventilation, and replaced by cold air. A window, with the usual accuracy of fitting, allows about eight 
 feet of air to pass by it in a minute, and there should be for ventilation at least three feet of air per 
 minute for each person in the room. According to this view, the quantity of steam-pipe or vessel 
 needed, under the temperature supposed, for a room 16 feet square by 12 feet high, with two windows, 
 each 7 feet by three, and with ventilation, by them or otherwise, at the rate of 16 cubic feet per minute, 
 would be — 
 
 For 42 square feet of glass (requiring 1 foot for 6) 7 feet. 
 
 “ 1238 feet of wall floor and ceiling (requiring 1 foot for 120) 10J “ 
 
 “ 16 feet per minute for ventilation (requiring 1 foot for 6) 2§ “ 
 
 Total of heating surface required 20 feet. 
 
 Which is 20 feet of pipe, 4 inches in diameter, or any other vessel having the same extent of surface, — 
 as a box two feet high, with square top and bottom of about 18 inches. It may be noticed, that nearly 
 the same quantity of heated surface would suffice for a larger room, provided the (quantity of window- 
 glass and of the ventilation were not greater ; for the extent of wall, owing to its slow conducting 
 quality, produces comparatively little effect. 
 
 The same authority also supplies the following illustrations : — A heated surface, as of iron, glass, 
 die., at temperatures likely to be met with in rooms, if exposed to colder air, gives out heat with ra- 
 pidity, nearly proportioned to the excess of its temperature above that of the air around it, less than 
 half the heat being given out by radiation, and more than half by contact of the air. Thus, if the ex- 
 ternal surface of an iron pipe, heated by steam, be 200°, while the air of the room to be warmed by it 
 is at 60°, showing an excess of temperature in the pipe of 140°, such pipe will give out nearly seven 
 times as much heat in a minute as when its temperature falls to 80°, because the excess is reduced to 
 20°, or \ of what it was. Supposing wdndow-glass to cool at the same rate as iron-plate, one foot of 
 the steam-pipe would give out as much heat as would be dissipated from the room into the external air 
 by about five feet of window, the outer surface of which were 30° warmer than (hat air. But as glass 
 both conducts and radiates heat about -1 slower than iron, the external surface of the glass of a 
 window of a room, heated to 60°, would, in an atmosphere of 22°, be under 50°, leaving an excess of 
 less than 30° ; and about six feet of glass would be required to dissipate the heat given off by one foot 
 of the steam-pipe. In double windows, whether of two sashes or of double panes, only half an inch 
 apart in the same sash, the loss of heat is only about one-fourth of what it is through a single window. 
 It is also known that one foot of black or brown iron surface, the iron being of moderate thickness, with 
 140° excess of temperature, cools in one second of time 156 cubic inches of water one degree. From 
 this standard fact, and the law above given, a rough calculation may be made for any other combina- 
 tion of time, surface, excess, and quantity. And it is to be recollected, that the quantity of heat which 
 changes, in any degree, the temperature of a cubic foot of water, produces the same change on 2850 
 cubic feet of atmospheric air. 
 
 The arrangement of the steam-pipes has next to be considered. A common method is shown in 
 Fig. 3704, in which a is the pipe from the boiler, rising at once to the upper story. From this pipe pro- 
 ceed horizontal branches b b to each floor. Each branch is furnished with a stop-cock at o, by which 
 means the steam can be turned on or off at pleasure, in any one of the three stories. The water aris- 
 
 3703. 
 
 J n t) 
 
 
 
 
 
 c 
 
 ’ 
 
 1 
 
 
 71 
 
 U 
 
 
 c 
 
 1 
 
 
 © 
 
 7 
 
 
WARMING AND VENTILATION. 
 
 801 
 
 3705. 
 
 3700. 
 
 ing from the condensation of the steam in each pipe flows back into the boiler along the ascending pipe 
 But if it be not convenient to place the boiler below the level of the lowest floor, the condensed steam 
 is received into a reservoir, from which it is pumped into the feeding-cistern. At the extremity of each 
 horizontal branch C is a stop-cock, which is opened when the steam is filling, to allow the air to blow off 
 
 Another arrangement of the heating pipes is shown in Fig. 3105. Steam from the boiler enters by 
 the connecting-pipe a into the heatiqg-pipe b, placed near the floor ; and this is carried, with a gentle 
 slope, to the opposite side of the room, whence it rises into the next story, and returns along its floor to 
 the opposite side, where it rises to the third floor, and proceeds as before. Here, also, the condensed 
 water flows back in a direction contrary 
 to the current of the steam, and is re- 3701. 
 
 moved by a siphon at a. The air-vent 
 is fixed at the highest point of the ar- 
 rangement c. 
 
 It is necessary to prevent the con- 
 densed water from accumulating in the 
 pipes, otherwise it would be impossible 
 to maintain them at a uniform tempera- 
 ture. Moreover, this water condenses the 
 steam so rapidly, that a vacuum is formed 
 within the boiler and pipes ; and should 
 they not be firm enough to resist the ex- 
 ternal pressure of the atmosphere, the boiler may be crushed in, and the whole system deranged. By a 
 special arrangement, the condensed water is collected at certain parts of the system, where it continues to 
 give out heat after the steam has ceased to flow into the pipes. In such 
 cases, stop-cocks may be employed, so arranged as to allow the water to 
 be afterwards withdrawn from the pipes ; the same cocks also serve for 
 letting the air out of the pipes when the steam is first admitted. But when 
 the water is returned into the boiler, the advantage of this supply of heat 
 cannot be reserved ; and in these cases, a self-acting apparatus is used 
 for taking off the water of condensation. Such a siphon is represented in 
 Fig. 3706. The pipes are so fixed, that A is the lowest point of a branch 
 pipe, so that any quantity of water that may be formed in it will flow 
 into the siphon, A 11 C, at A, and escape at C, where it may be received 
 into any vessel ; for as the water is pure distilled water, it may be useful 
 for a variety of purposes. The water in the legs of the siphon acts as a 
 trap to the steam in the pipe A ; hence, the length of the leg A B should 
 not be less than is equivalent to the force of the steam in the pipes. 
 
 When, for example, the steam is worked at the rate of ten pounds per 
 square inch, the column of water should not be less than ten feet ; and 
 even with this pressure, there will be considerable oscillations, unless a 
 valve be placed at some intermediate point between A and B. When 
 the legs are both filled with water, and at rest, this valve should be open, 
 so as to close whenever the water has a tendency to return into the pipe. 
 
 The siphon should be large enough to carry off all the water of condensa- 
 tion, but not too large, or there would be a loss of heat in the leg A B, 
 from its being filled with steam ; and, in all cases, the siphon should be 
 protected from frost. In connection with the siphon, it is usual to place 
 a cock for letting the air out of the pipe, instead of the stop-cock above 
 referred to. Such a cock is shown at E, and it is made to range with the 
 lower part of the pipe, because the air being heavier than steam, will occupy only the per portion of it. 
 
 In cases where sufficient depth cannot be afforded for a siphon, a steam-trap valve, made to 
 open by a float-ball, is, employed. Tredgold’s arrangement is as 
 follows : — B C, Fig. 3707, is a square box attached to the end A of 
 the steam-pipe; D is a hollow copper cylinder, fixed to a conical 
 valve E. When steam is condensed, the square box will fill with 
 water, which will float the hollow cylinder, and the water will 
 escape, and run by the pipe F into the drain. Whenever the quan- 
 tity of water in the box is greater than is required just to float 
 the cylinder, and when there is less than will float it, the valve 
 will be closed. In this case, also, a stop-cock S will be necessary 
 to let out the air while the pipes are being filled with steam. 
 
 The various methods of connecting the cast-iron pipes are by the 
 flange-joint, and the spigot and faucet, or socket-joint. Mr. Bu- 
 chanan gives minute directions for these, but he seems inclined to 
 recommend the thimble-joint. Care must of course be taken, in 
 joining the pipes, to allow room for expansion. This is sometimes 
 done in the thimble-joint, Fig. 3708, in which the adjoining ends of 
 the pipes a i are turned true on the outside, and have a thimble, 
 or short cylinder of wrought-iron, to inclose them, leaving only a 
 small space for the current. A piece of tin c, or inner thimble, is 
 interposed, and made to fit well to the turned parts of the pipes, 
 which, under the influence of heat or cold, work forwards or backwards, like a piston in a cylinder. In 
 a range of pipes T20 feet in length, there was a motion from expansion of three-quarters of an inch ; but 
 Vol. II.— 51 
 
 
802 
 
 WARMING AND VENTILATION. 
 
 the usual allowance for the expansion of cast-iron pipes is one-eighth of an inch in 10 feet, or c 
 their length. Cast-iron, heated from 32° to 212°, expands ? t-o of its Ie ngth, which is nearly 1| of an 
 inch in 100 feet. A similar expansion-joint applied to the spigot and faucet connection. Fig. 3709, am 
 swered very well. Lead cannot be substituted for tin or iron cement in joints, for, by frequent heating, 
 it becomes permanently expanded ; while the iron pipes always contracting in cooling, and the lead not 
 participating in the contraction, the joints soon get loose. Count, Rumford introduced an expansion- 
 drum x, Fig. 3710, of thin copper, between the extremities of two pipes a -which, in elongating, 
 pressed the sides of the drum inwards, and in cooling drew them outwards. The pipes should not be 
 connected with any part of the building, but be quite independent thereof. All the horizontal branches 
 should be supported on rollers, and nothing done to interfere with the expansion of the different parts 
 
 3708. 3710. 3711. 
 
 In private dwellings, where the appearance of the pipes is objectionable, they may be concealed be- 
 hind perforated mouldings, or skirtings, or cornices ; or the steam may be brought into ornamental 
 vases dispersed about the room, each furnished with a small stop-cock, to allow the air to escape while 
 the steam is entering. 
 
 The method of heating buildings by steam has been superseded by hot-water apparatus of various 
 kinds, which, however, may be resolved into two distinct forms or modifications, dependent on the tem- 
 perature of the water. In the first form of apparatus, the water is at or below the ordinary tempera- 
 ture of boiling. In this arrangement, the pipes do not rise to any considerable height above the level of 
 the boiler, so that the apparatus need not be of extraordinary strength. One pipe rises from the top of 
 the boiler, and traverses the places to be warmed, and returns to terminate near the bottom of the 
 boiler. Along this tube the heated water circulates, giving out its heat as it proceeds. The boiler 
 may be open or closed. If open, the tube, when once filled with water, acts as a siphon, having an as- 
 cending current of hot water in the shorter leg, and a descending current of cooled water in the longer 
 leg. If the boiler be closed, the siphon action disappears, and the boiler, with its tubes, becomes as one 
 vessel. In the second form of apparatus, the water is heated to 350° and upwards, and is, therefore, 
 constantly seeking to burst out as steam, with a force of 70 lbs. and upwards on the square inch, and 
 can only be confined by very strong or high-pressure apparatus. The pipe is of iron, about an inch in 
 diameter, made very thick. The length extends to 1000 feet and upwards ; and where much surface 
 is required fur giving out heat, the pipe is coiled up like a screw. A similar coil is also surrounded by 
 the burning fuel, and serves the place of a boiler. 
 
 The heating of rooms by the circulation of hot water in pipes seems to have occupied the attention 
 of a few speculative individuals, long before the attempt was actually made. The first successful at- 
 tempt, on a large scale, was made in France, in 1777, by M. Bonnemain, in an app;yatus for hatching 
 chickens, for the purpose of supplying the market of Paris. A section of this heating apparatus is 
 shown in Fig. 3711, in which a is the boiler, d a feed-pipe, o a stop-cock, for regulating the quantity of 
 ascending hot water, b the pipe by which the hot water ascends from the boiler into the heating pipes 
 c c which traverse the hatching-chamber. These heating pipes have a gradual slope towards the 
 boiler, to which the water returns by the pipe e, carried nearly to the bottom. In this way the water 
 cooled by being circulated through a long series of pipes, is being constantly returned to the lowest 
 part of the boiler, where it receives a fresh amount of heat ; and being thus rendered lighter, rises up 
 the pipe b, and descends the inclined planes of the pipes, losing a portion of its heat on the way, and at 
 the same time increasing in density ; the velocity of the current depending on the difference between 
 the temperature of the water in the boiler and that in the descending pipe. At the highest point of the 
 apparatus is a pipe i, furnished with a stop-cock for the escape of the air which the cold water holds in 
 solution on entering the boiler. The water that rises along with it is received into the vessel k. 
 
 Whatever be the arrangement adopted for warming buildings by this method, two considerations must 
 be specially attended to, viz., sufficient strength to bear the hydrostatic pressure, and freedom of motion for 
 currents of water, of varying temperatures, and consequently of varying densities. As fluids transmit 
 their pressure equally in every direction, a column of water rising from a strong vessel to a certain 
 height, may be made to burst the vessel with enormous force. Thus a tube whose sectional area is one 
 inch, rising to the height of 34L feet from the bottom of a vessel of water, will, if the tube be also full 
 of water, exert a bursting pressure on every square inch of the inner surface of such vessel of one at- 
 mosphere, or 15 lbs. If the sectional area of the tube be increased, the pressure remains the same, be- 
 cause it is distributed over a larger surface of the vessel. If a boiler be 3 feet long, 2 feet wide, and 2 
 feet deep, with a pipe 28 feet high from the top of the boiler, when the apparatus is filled with water, 
 there will be a pressure on the boiler of 66,816 lbs., or very nearly 30 tons. This will show the neces- 
 sity for great strength in the boiler, especially when it is considered that the effect of heat upon it is to 
 diminish the cohesive force of its particles. But even supposing the apparatus were to burst, no danger 
 would arise, because water, unlike steam, has but a very limited range of elasticity. The boiler just 
 described would contain about 75 gallons of water, which, under a pressure of one atmosphere on the 
 
WARMING AND VENTILATION. 
 
 80 :J 
 
 Equare inch, would be compressed about one cubic inch ; and if the apparatus were to burst, the expan- 
 sion would only be one cubic inch, and the only effect of bursting would be a cracking in some part of 
 the boiler, occasioning a leakage of the water. 
 
 The circulation of the water is brought about by the principle of convection. When heat is applied 
 to a vessel containing water, the principle of conduction altogether fails, for water is so imperfect a con- 
 ductor of heat, that if the fire be applied at the top, the water may be made to boil there without 
 greatly affecting the temperature below. But when the fire is applied below, the particles in contact 
 with the bottom of the boiler, being first affected by the heat, expand, and thus becoming specifically 
 lighter than the surrounding particles, ascend, and other particles take their place, which in like manner 
 becoming heated, ascend also ; and the process goes on in this way until the whole contents of the 
 boiler have received an accession of temperature. If the process be continued long enough, the water 
 will boil and pass off in steam. If the boiler be closed in on all sides, so as to prevent the escape of 
 steam, it will burst with a fearful explosion. If a tube full of water rise from the top of the boiler in a 
 vertical line to any required height, and then by a series of gentle curves descend, and enter near the 
 bottom of the boiler, the process of heating is still the same. The particles of water first heated will 
 rise, and, in doing so, distribute their heat to other particles, which will also rise. These in their turn 
 will lose a portion of their- heat to other particles, which rise in their turn ; until at length an equilibrium 
 is established. But as the source of heat is permanent, other particles are rapidly brought under its 
 action, and, being heated, ascend. By continuing the process a short time, the particles in the vertical 
 tube become heated, and, by their expansion, exert a pressure on the water contained in the lateral 
 branches. This, together with the increasing levity of the water in the boiler, establishes a current, and 
 the water from the branches begins to set in in the direction of the boiler ; the water in the lowest 
 branch, where it enters the boiler, supplying colder and heavier particles every moment to take the 
 place of the warmer and lighter particles which are being urged upwards along the vertical pipe. 
 
 Now to ascertain the force with which the water returns to the boiler, we must know the specific 
 gravities of the two columns of water, the ascending and the descending, and the difference between 
 them will be the effective pressure or motive power. This can be done by ascertaining the temperature 
 of the water in the boiler and in the descending pipe. When the difference amounts to only a few de- 
 grees, the difference in weight is very small, but quite sufficient, in a well-arranged apparatus, to main- 
 tain a constant circulation. For example, suppose an apparatus to be at work, in which the tempera- 
 ture in the descending pipe is 170 deg., and the temperature of the water in the boiler, the height of 
 which is 12 inches, is 178 deg. The difference in weight is 8'16 
 grains on each square inch of the section of the return pipe. If 
 the boiler A, Fig. 8712, be two feet high, and the distance from 
 the top of the upper pipe c to the centre of the lower pipe d be 
 18 inches, and the pipe four inches in diameter, the difference of 
 pressure on the return pipe will be 153 grains, or about one-third 
 of an ounce weight ; and this will be the amount of motive power 
 of the apparatus, whatever he the length of pipe attached to it. If such an apparatus have 1 00 yards 
 of pipe, four inches in diameter, and the boiler contain 30 gallons, there will be 190 gallons or 1900 
 lbs. weight of water kept in continual motion by a force equal to only one-third of an ounce. 
 
 Another method of estimating the velocity of motion of the water of a hot-water apparatus, is to 
 regard the two portions of the system as the lighter and heavier fluids in the two limbs 
 of a barometrical a-friometer. This instrument is an inverted siphon, Fig. 3713, and its 
 use is to ascertain, irv a rough way, the specific gravities of immiscible fluids. If mercury 
 be poured into one limb A and water into the other B, and the stop-cock between them 
 be turned so as to establish a communication, it will be found that an inch of mercury 
 F D in one limb will balance 13J inches of water I E in the other limb, thus showing that 
 the densities or specific gravities of the two fluids are as 13 J to 1. If oil be used instead 
 of mercury, it will require 10 inches of oil to balance 9 inches of water. Or if equal bulks 
 of oil and water be poured into the limbs of the siphon and the stop-cock be then turned, 
 the oil will be forced upwards with a velocity equal to that which a solid body would ac- 
 quire in falling by its own gravity, through a space equal to the additional height which 
 the lighter body would occupy in the siphon. Now as the relative weights of water and 
 oil are as 9 to 10, the oil in one limb will be forced upwards by the water with a velocity 
 equal to that which a falling body (in this case the water) would acquire in falling 
 through one inch of space, and this velocity is equal to 138 feet per minute. 
 
 In estimating the velocity of motion of the water in a hot-water apparatus, the same 
 rule will apply. “If the average temperature be 170 deg., the difference between the 
 temperature of the ascending and descending columns 8 deg., and the height 10 feet ; 
 when similar weights of water are placed in each column, the hottest will stand '331 of 
 an inch higher than the other, and this will give a velocity equal to 79'2 feet per minute. If the height 
 be five feet, the difference of temperature remaining as before, the velocity will be only 55'2 feet per 
 minute ; but if the difference of temperature in this last example had been double the amount stated— 
 that is, had the difference of temperature been 16 deg., and the vertical height of the pipe five feet — 
 then the velocity of motion would have been 79'2 feet per minute, the same as in the first example, 
 where the vertical height was 10 feet, and the difference of temperature 8 deg.” 
 
 But in all these calculations a considerable deduction must be made for the effects of friction. In the 
 centre of the ascending pipe, the heated particles meet with the smallest amount of obstruction, and 
 there the motion is quickest ; but at and near the circumference of the pipe, the retarding effects of 
 friction are most apparent. In the descending pipe the friction is less, for the water descends more as 
 a whole, and is, moreover, assisted by the gravity of the mass. In an apparatus where the length of 
 pipe is not great, where the pipes are of large diameter, and the bends and angles few, a large deduc. 
 
804 
 
 WARMING AND VENTILATION. 
 
 tion from the theoretical amount must still be made, to represent 'with any thing like accuracy the true 
 velocity ; and Mr. Hood states that in more complex apparatus the velocity of circulation is so much 
 reduced by friction that it will sometimes require from 50 to 90 per cent, and upwards to be deducted 
 from the calculated velocity, in order to obtain the true rate of circulation. 
 
 The amount of friction not only varies according to the arrangement of the apparatus, but also ae 
 cording to the size of the pipes. It is much greater in small pipes than in large ones, on account of the 
 relatively larger amount of surface in the former; besides this, small pipes cool quicker than large }nes, 
 and this increases the velocity of the circulation, and with it the friction is also increased. When the 
 velocity with which the water flows is the same in pipes of different sizes, tne relative amount of friction 
 is as follows : 
 
 Diameter of the pipes, ^ in., 1 in., 2 in., 3 in., 4 in. 
 
 The amount of friction, 8, 4, 3, T3, 1. 
 
 3714. 
 
 So that, if the friction in a pipe of 4 inches diameter be represented by 1, the friction of a pipe 2 
 inches in diameter is twice as much, and a 1-inch pipe four times as much. By increasing the velocity, 
 the friction increases nearly as the square of the velocity; but as the water in a hot-water apparatus 
 circulates with various degrees of speed in its different parts, it is not easy to calculate the amount of 
 friction from this cause. 
 
 It will be seen, then, that when all the deductions are made, the circulation of the water is produced 
 by a very feeble power, so that, as may be supposed, a very slight cause is sufficient to neutralize it. 
 Mr. Hood has known so trifling a circumstance as a thin shaving accidentally getting into a pipe, effect- 
 ually to prevent the circulation in an apparatus otherwise perfect in all its parts. 
 
 But the great point to be attended to, is so to dispose the pipes, that the water, in its descent, may 
 not be obstructed by differences ; level, or angles in the pipes, where air may accumulate ; for this, 
 by dividing the stream, effectually prevents the circulation. For example, in an apparatus constructed 
 in the form represented in Fig. 3714, the motion through the boiler 
 and pipe A B takes place by convection, and through the descend- 
 ing pipe C D by the force of gravity, as already described. But 
 it will be seen that, when the motion commences in the return 
 pipe D B, in consequence of the greater pressure of C D than of 
 A B, the water in A will be forced towards e, while the water in 
 ef g h flows towards C. But when a very small quantity of hot 
 water has passed from the pipe and boiler A B into the pipe ef 
 the column of water g h will be heavier than the column ef and 
 the current will, therefore, tend to move along the upper pipe 
 towards the boiler, instead of from it. This force, whatever its 
 amount, must oppose that in the lower or return pipe, in conse- 
 quence of the pressure of C D being greater than A B ; and unless the force of motion in the descend- 
 ing pipe C D be sufficient to overcome this tendency to a retrograde motion, and leave a residual force 
 sufficient to produce direct motion, no circulation of the water can take place. 
 
 With respect to the accumulation of air in the pipes, every part of the apparatus, where an altera- 
 tion of level occurs, must be furnished with a vent for the air. Thus, in Fig. 3714, if the air accumu- 
 late in the pipe between A and e, it is evident that a vent at C, although it would take off the air from 
 g h , and from C D, could not receive any portion of that which is confined between A e, or between ef 
 because, in that case, it must descend through the pipe ef before it could escape, and as air is so very- 
 much lighter than water, it cannot possibly descend so as to pass an obstruction lower than the place 
 where it is confined. The same remark applies to all cases, however large or small the descent may 
 be, and the accidental misplacing of a pipe in the fixing, by which one end may be made a little 
 higher than the other, will as effectually prevent the escape of air through a vent placed at the lower 
 end, as though the deviation from the level were as many feet as it may, perhaps, be inches. 
 
 When it is required to heat a number of separate stories by the 
 same boiler, one of two methods may be adopted. The vertical pipe 
 from the boiler may be carried up to the highest story, and the re- 
 turn pipe meander through each story, until it finally terminates in 
 the boiler. But it is obvious, that in such case, the top story will get 
 the larger share of the heat, and the lower stories will be gradually 
 less heated, on account of the cooling of the water in its passage to 
 the boiler. The second method is to supply each story with a sep- 
 arate range of pipes branching out from the main pipe, and returning 
 either together or separately into the boiler. The application of 
 this principle, however, requires caution, for if the branch pipes are 
 simply inserted into the side of a vertical ascending pipe, the hot 
 current may pass by, instead of flowing into, them. Some con- 
 trivance is, therefore, necessary to delay the motion of the upward 
 current, and to cause it to turn aside at the points required. This 
 may be done by the arrangement shown in Fig. 3715, which is 
 also copied from Mr. Hood’s work. Here it will be perceived, 
 that as the water ascends from the boiler B it receives a check at 
 b, whereby it tends to flow through the horizontal pipe, at that 
 level. The same also occurs at c, and, by this means, a nearly 
 equal flow of hot water may be obtained. If it be required to 
 cut off the supply of heat from one story, while the others are 
 being heated, this may be done by turning a stop-cock at s, by 
 
 3715. 
 
WARMING AND VENTILATION. 
 
 805 
 
 which the heated current is prevented from flowing along the particular branch so closed. But when- 
 ever a branch is closed as at s, it is necessary also to close the other end t of the same branch, other- 
 wise the water in the descending return pipe R, being warmer and lighter than that in the branch closed 
 at s, will circulate therein, and thus raise the temperature of the room intended to be kept cool. 
 
 In some arrangements, the hot ascending current of the vertical main is made to discharge into an 
 open cistern at the top, as in Fig. 3716, and from the bottom of this cistern the various flow-pipes are 
 made to branch off. By this means, the expense of cocks or 
 valves is avoided ; for by driving a wooden plug into one or 
 more of the pipes which open into the cistern, the circulation 
 will be stopped until the apparatus is heated ; but, in that 
 case, water will flow back through the return pipe. This, 
 however, may be prevented, by bending a lower portion of 
 the return pipe into the form of an inverted siphon, as shown 
 in the figure. This will not prevent the circulation when the 
 flow-pipe is open ; but if that be closed by a plug in the 
 cistern, the hot water will not return back through the lower 
 pipe. Any sediment that may accumulate in the siphon may 
 be removed, from time to time, by taking off the cap at the 
 lower part of the bend. 
 
 In such an arrangement as that shown in the last two figures, the vertical main £ .pe need not be 01 
 larger diameter than the branches, unless these extend to a very considerable distance, and then the 
 diameter of the main pipe may be somewhat enlarged. It is not, however, desirable to increase the 
 diameter of the main, because it is an object to economize the heat in this pipe, and there are circum- 
 stances in which a small main loses less heat than a large one, as, for example, in the arrangement 
 shown in Fig. 3716. If one main pipe, eight inches in diameter, supply four branches in a given time, 
 it is evident, that by reducing the main to four inches in diameter, the water must travel four times 
 faster through the smaller pipe to perform the same amount of work ; and, under such circumstances, 
 the water will lose only half as much heat in passing through the small main as it would do in ascend- 
 ing the larger one, for , the loss of heat sustained by the water is directly as the time and the surface 
 conjointly. ’ 
 
 Hence, in warming' by the same boiler two rooms separated from each other, by a considerable dis- 
 tance, the pipe connecting the two rooms may be of smaller diameter than the pipes used for diffusing 
 the heat Thus a pipe of one inch diameter may be used to connect pipes four inches in diameter. 
 
 The great specific heat of water, whereby it is enabled to retain its heat for a very long time, has 
 been already shown (page 743) to be a great advantage of this method of warming buildings. The 
 rate at which this apparatus cools depends chiefly on the quantity of water coritaiued in it with respect 
 to the amount of surface exposed, and the excess of temperature of the apparatus above that of the 
 surrounding air ; but for temperatures below the boiling point, this last circumstance need only be taken 
 into account in estimating the velocity with which this apparatus cools. Now the variation in the rate 
 of cooling for bodies of all shapes, is inversely as the mass divided by the superficies. In cylindrical 
 pipes, the inverse number of the mass divided by the superficies is exactly equal to the inverse of the 
 diameters ; so that, supposing the temperature to be the same in all, 
 
 In pipes of 1 2 3 4 inches diameter, 
 
 The ratio of cooling will be 4 2 T3 1 “ 
 
 That is, a pipe of one inch in diameter will cool four times as quickly as a pipe of four inches in 
 diameter, and so on. These ratios, multiplied by the excess of heat in the pipes above that of the 
 surrounding air, will give the relative rates of cooling for different temperatures below 212 deg.; but 
 if the temperatures be the same in all, the simple ratios given above will show their relative rate of 
 cooling without multiplying by the temperatures. 
 
 These calculations supply practical rules for estimating the size of the pipes under different circum- 
 stances. If the heat be required to be kept up long after the fire is extinguished, large pipes should 
 be used ; if, on the contrary, the heat is not wanted after the fire is put out, then small ones will answer 
 the purpose. Pipes of larger diameter than four inches should never be used, because they require a 
 very long time in being heated to the proper temperature. Pipes of four inches in diameter are well 
 adapted for hot-houses, green-houses, and conservatories. Pipes of two or three inches may be used 
 for warming churches, factories, and dwelling-houses ; such pipes retain their heat for a sufficient length 
 of time, and they can be more quickly and more intensely heated than larger pipes, so that, on this 
 account, a smaller quantity of pipe will often suffice. 
 
 With respect to the quantity of pipe required for warming a building of ascertained size, it is neces- 
 sary to bear in mind the rate at which a given quantity of hot water, in an iron pipe, will impart its 
 heat to the surrounding air. Now, it has been shown by Mr. Hood, that the water contained in an iron 
 pipe four inches in diameter internally, and four and a half inches externally, loses "Sol of a degree of 
 heat per minute when the excess of its temperature is 125 deg. above that of the surrounding air ; and, 
 as one cubic foot of water in losing 1 deg. of its heat will raise the temperature of 2990 cubic feet of 
 air the like extent of 1 deg., so one foot length of four-inch pipe will heat 222 cubic feet of air 1 deg. 
 per minute, when the difference between the temperature of the pipe and the air is 125 degrees. 
 
 We must now take into account the loss of heat per minute arising from the cooling power of glass, 
 ventilation, radiation, cracks in doors and windows, and other causes. An allowance of from three and 
 a half to five cubic feet of air ought to be made per minute for each person in the room, so that, for 
 the purposes of respiration, this quantity will have to be discharged, and an equal supply of air brought 
 in to be warmed. 
 
 One square foot of glass will cool 1'279 cubic feet of air as many degrees per minute as me internal 
 
 3716. 
 
806 
 
 WARMING AND VENTILATION. 
 
 temperature of the room exceeds the temperature of the external air. If the difference between ther. 
 be 30 deg., the T279 cubic feet of air will be cooled 30 deg. by each square foot of glass, that is, aj 
 much heat as is equal to this will be given off by each square foot of glass. 
 
 The quantity of air to be warmed per minute in habitable rooms and public buildings must be three 
 and a half cubic feet for each person the room contains, and one and a quarter cubic feet for each square 
 foot of glass. For conservatories, forcing-houses, and other buildings of this description, the quantity 
 of air to be warmed per minute must be one and a quarter cubic feet for each square foot of glass 
 which the building contains. When the quantity of air required to be heated has been thus ascertained, 
 the length of pipe which will be necessary to heat the building may be found by the following rule : — 
 multiply 125 (the excess of temperature of the pipe above that of the surrounding air) by the differ- 
 ence between the temperature at which the room is purposed to be kept when at its maximum, and 
 the temperature of the external air ; and divide this product by the difference between the temperature 
 of the pipes and the proposed temperature of the room ; then, the quotient thus obtained, when mul- 
 tiplied by the number of cubic feet of air to be warmed per minute, and this product divided by 222 
 (the number of cubic feet of air raised 1 deg. per minute by one foot of 4-inch pipe) will give the 
 number of feet in length of pipe four inches diameter, which will produce the desired effect. 
 
 When 3-incli pipes are used, the quantity of pipe required to produce the same effect will, of course, 
 be different. To obtain it, the number of feet of 4-inch pipe obtained by the above rule must be mul- 
 tiplied by l - 33. If 2-inch pipe be used, the quantity of 4-inch pipe must be multiplied by two. 
 
 If we wish to determine the quantity of pipe required to maintain a constant temperature of 75 deg. 
 in a hot-house, we must suppose the external air occasionally to fall as low as 10 deg., and calculate 
 from this temperature. The amount of heat to be supplied by the pipes is obviously that which is 
 expended by the glass, the cooling power of which is exactly proportioned to the difference between 
 the internal and the external temperature, the actual cubical contents of the house making no difference 
 in the result. If such a house have 800 square feet of glass, it can easily be calculated, from the pre- 
 ceding data, that this quantity will cool down 1000 cubic feet of air per minute from 75 deg. to 10 deg., 
 which will require 292 feet of 4-inch pipe. If the maximum temperature of the pipe be 200 deg., and 
 the water be at 40 deg. before lighting the fire, the maximum temperature will be attained in about 
 four hours and a half ; with 3-inch pipe, in about three hours and a quarter ; and with 2-inch pipe, in 
 about two hours and a quarter ; depending, however, upon the structure of the furnace, and the quantity 
 of coal consumed. If the external temperature be higher than 10 deg., the effect will be produced in 
 a proportionally shorter time. 
 
 In churches and large public rooms, with an average number of doors and windows, and moderate 
 ventilation, a more simple rule will apply for ascertaining the quantity of pipe required. Where a 
 number of persons are assembled, a large amount of heat is generated by respiration, so that a very 
 moderate artificial temperature is sufficient to prevent the sensation of cold. In such a case, the air 
 does not require to be heated above 55 deg. or 58 deg., and the rule is to take the cubical measurement 
 of the space to be heated, and dividing this by 200, the quotient will be the number of feet of 4-inch 
 pipe required. 
 
 The efficiency of any form of hot-water apparatus will, of course, greatly depend on the boiler, 
 which ought to be so constructed as to expose the largest amount of surface to the fire in the smallest 
 space ; to absorb the heat from the fuel, so that as little as possible may escape up the chimney ; to 
 allow free circulation of the water throughout its entire extent, and not be liable to get out of order by 
 constant use. A variety of boilers are figured in Mr. Hood’s work, and their respective merits con- 
 sidered on scientific grounds. One of these boilers is shown in Fig. 3717. 3717. 
 
 It is of cast-iron, and the part exposed to the fire is covered with a series 
 of ribs two inches deep, and about one-fourth or three-eighths of an inch 
 thick, radiating from the crown of the arch at an average distance of two 
 inches from each other. These ribs greatly increase the surface exposed 
 to the fire, exactly where the effect is greatest ; for being immediately over 
 the burning fuel, it receives the whole of the heat radiated by the fire. The form of this boiler being 
 hemispherical, will also expose the largest amount of surface within a given area. The boiler shown 
 in Fig. 3715 being of wrought-iron, and, therefore, thinner than cast-iron, absorbs the greatest amount 
 of heat from the fuel. 
 
 With respect to the size of the boiler, it has been shown by experiment that four square feet of sur- 
 face in an iron boiler will evaporate one cubic foot of water per hour when exposed to the direct action 
 of a tolerably strong fire. The same extent of heating surface which will evaporate one cubic foot of 
 water per hour from the temperature of 52 deg., will be sufficient to supply the requisite amount of 
 heat to 232 feet of 4-inch pipe, the temperature of which is required to be kept 140 deg. above the sur- 
 rounding air ; or one square foot of boiler surface exposed to the direct action of the fire, or three square 
 feet of flue surface, will supply the necessary heat to about 58 superficial feet of pipe ; or, in round num- 
 bers, one foot of boiler to 50 feet of pipe. But as this is the maximum effect, a somewhat larger allow- 
 ance ought in general to be made. If the difference of temperature be 120 deg. instead of 140 deg., 
 the same surface of boiler will supply the requisite amount of heat to one-sixth more pipe, and if the 
 difference be only 100 deg., the same boiler will supply above one-third more pipe than the quantity 
 stated. 
 
 With respect to the furnace, the rate of combustion of the fuel will depend chiefly on the size of the 
 furnace-bars, provided the furnace-door be double and fit tightly. The ash-pit should also be provided 
 with a door to exclude the excess of air when the fire is required to burn slowly. A dumb-plate should 
 also be provided, to cause the combustion to be most active at the hinder part of the furnace instead of 
 directly under the boiler. The fuel will thus be gradually coked, the smoke consumed, and the fuel 
 economized. 
 
 In an apparatus containing 600 feet of 4 inch pipe, the area of the furnace-bars should be 300 square 
 
WARMING AND VENTILATION. 
 
 80 ? 
 
 inches, so that 14 inches in width and 22 inches in length will give the amount of surface required. Tc 
 obtain the greatest heat in the shortest time, the area of the bars should be proportionally increased, 
 so that a larger lire may be obtained. The fire ought at all times to be kept thin and bright; and to 
 obtain a good effect from the fuel, one pound weight of coal ought to raise 39 lbs. of water from 32 
 degrees to 212 degrees. 
 
 The best kind of pipes for hot-water apparatus are those with socket-joints, flange-joints having long 
 been out of use for this purpose. Where the socket-joints are well made, there is no fear of leakage, 
 for the pipes themselves will yield before the joints will give way, or before the faucet end^f one pipe 
 can be drawn out of the socket of the other. The joints must be well caulked with spun yarn, and 
 tilled up with iron cement, or with a cement made of quicklime and linseed oil. 
 
 Soft or rain water ought always to be used in the hot-water apparatus, because, if hard water be 
 used, its salts will form a sediment or crust in the boiler, and interfere with its action. But as there is 
 very little evaporation from this kind of apparatus, the boiler will not require cleaning out for years, 
 if a moderate degree of attention be bestowed on the water employed. 
 
 When the apparatus is not in use, care must be taken to prevent the water from freezing in the pipes, 
 or the sudden expansive force of the water in freezing may crack them. If the apparatus is not likely 
 to be used for some time during winter, it is better to empty the pipes than incur the risk of free/, 
 ing. It has been proposed to till the pipes with oil instead of water, and as the boiling point of oil is 
 nearly three times higher than that of water, it was thought that a temperature of 400 deg. might 
 be safely given to the pipes. It was found, however, that the oil at high temperatures became thick and 
 viscid, and at length changed into a gelatinous mass, completely stopping all circulation in the pipes. 
 
 In the forms of apparatus to which the preceding details refer, the temperature of the water never 
 rises to the ordinary boiling point, (212 deg. ;) but we have now to notice a method in which the tem- 
 perature of the water is often beyond 300 deg. ; this is the high-pressure method contrived by Mr. 
 Perkins. In its simplest form, the apparatus consists of a continuous or endless pipe, closed in all parts, 
 and filled with water. There is no boiler to this apparatus, its place being supplied by coiling up a 
 portion of the pipe (generally one-sixth of the whole length) and arranging this in the furnace. The 
 remaining five-sixths of the pipe are heated by the circulation of the hot water, which flows from the 
 top of the coil, and cooling in its progress through the building, returns to the bottom of the coil to be 
 reheated. The diameter of the pipe is one inch externally, and half an inch internally, and is formed 
 of wrought-iron. The coil in the furnace being entirely surrounded by the fire, the water is quickly 
 heated, and becoming also filled with innumerable bubbles of steam, these impart a great specific 
 levity to the ascending current. At the upper part of the pipe, the steam bubbles condense into water, 
 and uniting with the column in the return pipe, which is comparatively cool, the descent is rapid in 
 proportion to the expansion of the water in the ascending column, or, in other words, according to the 
 relative specific gravities of the two columns of water. 
 
 As the expansive force of water is almost irresistible, in consequence of its extremely limited elas- 
 ticity, it is necessary in the high-pressure apparatus to make some provision for the expansion of the 
 water when heated. The necessity for this will appear from the fact, that water heated from 39'45 deg. 
 (the point of greatest condensation) to 212 deg., expands about l-23d part of its bulk; and the force 
 exerted on the pipes by this expansion would be equal to 14,121 lbs. on the square inch. The method 
 adopted is to connect a large pipe, called the expansion-pipe, 2^- inches diameter, with some part of the 
 apparatus, either horizontally or vertically. It should be placed at the highest point of the apparatus, 
 and at the bottom of the expansion-pipe is inserted the filling-pipe through which the apparatus is filled. 
 While the apparatus is being filled with water, the expansion-tube is left open at the top ; water is then 
 poured in through the filling tube, and as it rises in the pipes, drives out the air before it. When the 
 pipes are full, the filling-pipe and the expansion-tube are carefully closed with screw-plugs. It is im- 
 portant to expel all the air from the pipes, and this is done, in the first instance, by pumping the water 
 repeatedly through them. The expansion-pipe is, of course, left empty, as its use is to allow the water 
 in the pipes to expand on being heated, and thus prevent the danger of bursting. From 15 to 20 per 
 cent, of expansion space is generally allowed in practice. 
 
 The furnace is generally so arranged in the building required to be heated, as to allow the tube pro- 
 ceeding from the top of the coil to be carried straight up at once to the highest level at which the water 
 has to circulate ; here the expansion-tube is situated, and from this point two or more descending 
 columns can be formed, which, after circulating through different and distant parts of the building, 
 unite at length in one pipe, just before entering the bottom of the coil in the furnace. 
 
 The whole arrangement will be better understood by referring to Fig. 3718, in which a is the ascend- 
 ing column ; 5, the expansion-tube ; c, the descending columns ; d, the coil in the furnace ; and ss s s, 
 stop-cocks for turning off the circulation from the coils when desired. 
 
 The heat is communicated to the air of the rooms from the external surface of the pipes, which are 
 coiled up as at e e, and placed within pedestals, ranged about the room with open trellis- work in front, 
 or they may be sunk in stone floors, placed behind skirtings, or in the fireplaces of each floor, the flues 
 being stopped, or arranged in any other convenient manner. 
 
 In consequence of the great internal pressure which these tubes have to sustain, considerable care 
 is required in their manufacture. They are made of the best wrought-iron, rolled into sheets a 
 quarter of an inch thick, and of the projrer width. The edges are then brought nearly together the 
 whole length of the iron, which is generally about 12 feet. In this state it is placed in a furnace, and 
 heated to a welding heat. One end is then grasped by an instrument firmly attached to an endless 
 chain, revolving by steam power, and a man applies a pair of circular nippers, which, when closed, press 
 the tube into the required size, and which lie holds firmly while the tube is drawn through them by the 
 engine. The edges are thus brought into perfect contact, and are so completely welded after passing 
 I wo or three times through the nippers, that a conical piece of iron driven into the end of the tube wiD 
 not opeu it at the joint sooner than at any other part. 
 
>508 
 
 WARMING AND VENTILATION. 
 
 When the tubes are screwed together at each end, they are proved by hydrostatic pressure, with s 
 force equal to 3000 lbs. on the square inch of internal surface. 
 
 When the tubes are properly arranged and fixed in the building, the whole apparatus is filled with 
 water by a force-pump, and subjected to considerable pressure, before lighting the fire. In this way 
 faulty pipes or leaky joints are detected. 
 
 The tubes are joined by placing the ends within a socket, forming a right and left hand screw, the edge 
 of one tube having been flattened, and the other sharpened ; they are then screwed so tightly together, 
 that the sharpened edge of one pipe is indented in the flattened surface of the other. Another method 
 of connecfing the pipes is by a cone-joint. A double cone of iron is inserted into the ends of the pipes 
 to be joined, and is made tight by two screw-bolts, as shown in Fig. 3719. This joint is quickly made, 
 and is very strong. 
 
 3718. 
 
 3719. 
 
 3720. 
 
 The furnace varies in form and dimensions according to circumstances ; but a very common arrange- 
 ment is shown in Fig. 3720. The size is about three and a half feet square, increasing to six feet, 
 according to the extent of pipe connected with it. The fire occupies a small space in the centre, raised 
 about one foot from the ground, and the fuel is supplied through the hopper-door m, at the top. The 
 outer casing a is of common brick-work ; cc are fire-bricks, supporting the coil k ; dd reservoirs for the 
 dust and soot, which would otherwise clog the coil ; g bearing-bars for the grate ; h the grate : the fire-door 
 is double, and there are also doors to the ash-pit and dust reservoirs. Fig. 3721 shows the descending 
 tube entering the fire-chamber, and passing through the bearing-bars g g of the grate h. Fig. 3722 is a 
 section of the back well or reservoir d d, formed so as to support the coil, and to cause the soot and dust 
 to fall to the bottom. 
 
 In this arrangement of the furnace, the ignited coal is surrounded on three sides by a thickness ot 
 nine-inch fire-brick ; the hopper-door is also placed in one of these lumps ; the coil is contained in a 
 chamber round the fire-brick, four and a half inches wide ; the pipe enters this chamber, passing through 
 
WARMING AND VENTILATION. 
 
 309 
 
 the bearing-bars of the grate, which tends to preserve the grate from burning ; the pipe passes out from 
 the top of the coil, at the upper part. of the chamber. The smoke passes through the chamber con- 
 taining the pipes, and escapes through an opening at the back. The coil is in actual contact with tire 
 fire only in front. The best fuel for this furnace is coke or Welsh hard coal, such as is not liable to clog. 
 The furnace may be placed in a cellar, or be completely removed from the building to be warmed. 
 The heat of the furnace can be moderated by closing the ash-pit door, and opening the furnace door, or 
 the reservoir doors, so as to lesson the draught and admit cold air to the coil. 
 
 In the apparatus erected at the British Museum for warming the print-room and the bird-room, the 
 furnace is in a vault in the basement story, and the pipes, entering a flue, are carried up about forty 
 feet to two pedestals, one in each room ; one containing 360 feet of pipe, and the other 400 feet. About 
 140 feet of pipe are employed in the flow and return pipes in the flue, and 150 feet are coiled up in 
 the furnace. In this way, 1050 feet of pipe are employed: the apparatus is very powerful, and sup- 
 plies the requisite amount of heat. The print-room is about 40 feet long, by 30 feet wide, and the 
 ceiling contains large sky-lights. The temperature of 65 deg. can easily be maintained in this room 
 during winter. The fire is lighted at 0 a. m., and is allowed to burn briskly till sufficient heat is pro- 
 duced in the rooms, when the damper in the flue is partially closed. A slow fire is thus maintained : 
 at 11 a. m., a fresh supply of fuel is added, and this supports the fire till 4 p. m., when all the fires at the 
 Museum are extinguished. 
 
 The above details will suffice to show the nature and application of this apparatus. 
 
 It is, however, of great importance to ascertain whether this apparatus is perfectly safe, for even a 
 doubt on the subject must be fatal to its general introduction. The average temperature of the pipes 
 is stated to be generally about 350 deg. ; but a very material difference in temperature, amounting 
 sometimes to 200 deg. or 300 deg., is said to occur in different parts of the apparatus, in consequence 
 of the great resistance which the water meets with in the numerous bends and angles of this small 
 pipe. The temperature of the coil will, of course, give the working effect of the apparatus, but the 
 temperature of any part of the pipe will furnish data for estimating its safety ; for whatever is the 
 temperature, and, consequently, the pressure in the coil, must be the pressure on any other part of the 
 apparatus ; for by the law of equal pressures of fluids, an increased pressure at one part will generate 
 an equally increased pressure at every other part of the system. 
 
 A very elegant method of ascertaining the temperature* of a heated surface of iron or steel, consists 
 in filing it bright, and then noting the color of the thin film of oxide which forms thereon, as follows : 
 
 Steel becomes a very faint yellow at 430 deg. Fahr. 
 
 “ pale straw-color “ 450 “ 
 
 “ full yellow “ 470 “ 
 
 “ brown “ 490 “ 
 
 “ brown, with purple spots “ 510 “ 
 
 “ purple.. “ 530 “ 
 
 blue “ 550 “ 
 
 “ full blue “ 560 “ 
 
 “ dark blue, verging on black “ 600 “ 
 
 Mr. Hood states, that in some apparatus, if that part of the pipe which is immediately above the lur 
 nace be filed bright, the iron will become of a straw color, showing a temperature of about 450 deg. 
 In other instances, it will become purple = about 530 deg., and, in some cases, of a full blue color = 
 660 deg. Now, as there is always steam in some part of the apparatus, the pressure can be calculated 
 from the temperature, and a temperature of 450° = a pressure of 420 lbs. ou the square inch ; 630° = 
 900 lbs. ; and 560° = 1150 lbs. per square inch. 
 
 Although these pipes are proved, at a pressure of nearly 3000 lbs. per square inch, and the force 
 required to break a wrought-iron pipe of one inch external, and half an inch internal diameter, requires 
 8822 lbs. per square inch on the internal diameter, yet these calculations are taken for the cold metal. 
 By exposing iron to long-continued heat, it loses its fibrous texture, and acquires a crystalline character, 
 whereby its tenacity and cohesive strength are greatly weakened. 
 
 In order to make this apparatus safe, Mr. Hood suggests that, instead of hermetically sealing the 
 expansion-pipe, it should be furnished with a valve so contrived as to press with a weight of 185 lbs. 
 on the square inch. This would prevent the temperature from rising above 350 deg. in any part : the 
 pressure would then be nine atmospheres, which is a limit more than sufficient for any working appa- 
 ratus where safety is of importance. 
 
 But, supposing the apparatus were to burst in any part, the effects would, by no means, resemble those 
 which accompany the explosion of a steam-boiler. One of the pipes would probably crack, and the 
 water, under high-pressure, escaping in a jet, a portion of it would instantly be converted into steam, 
 while that which remained as water would sink to 212 deg. This would have the effect of scalding 
 water under ordinary circumstances, but the high-pressure steam would not scald, because its capacity 
 for latent heat is greatly increased by its rapid expansion, on being suddenly liberated, so that 
 instead of imparting heat, it abstracts heat from surrounding objects. The only real danger that 
 would be likely to ensue, would be from the jet of hot water, and this must, in any case, be of trifling 
 amount. 
 
 The methods of warming most generally practised in this country are the hot-air furnaces, so called 
 in which anthracite coal is consumed in an inclosed iron furnace, lined usually with fire-brick, and placed 
 within a brick chamber, either double or single ; and the heated air, after being moistened by the evap- 
 oration of water, is conveyed through the building !y tin conductors. The external air is introduced in 
 iarge quantities, supplying the means of a continuous curren'- of fresh warm air. We give several 
 methods now ii_ use 
 
810 
 
 WARMING AND VENTILATION. 
 
 Culver's hot-air and portable furnaces . — These furnaces are represented in the accompanying draw 
 ings, Figs. 3723, 3724, and 3725. 
 
 A, Fig. 3723, iron or brick ash-pit. 
 
 B, ash-pit door. 
 
 C, pot, or coal-burner, with or without soap- 
 stone lining. 
 
 D, fire-chamber. 
 
 E, lower half of tubular drum. 
 
 F, elliptical tubes. 
 
 G, upper half of tubular drum. 
 
 II, top of tubular drum. 
 
 1, cap and smoke-pipe. 
 
 K, flat radiator. 
 
 L, water-basin, or evaporator. 
 
 M, smoke-pipe to chimney. 
 
 N, conductors of hot air. 
 
 O, cold-air conductor and chamber. 
 
 P, feed-door. 
 
 Q, hot-air chamber. 
 
 It, damper in globe with rod attached. 
 
 S, pendulum valve for cleaning. 
 
 The arrows show the direction of the currents of 
 
 hot or cold air. 
 
 Fig. 3724 represents a large size portable fur- 
 nace in outline or skeleton form, in double cover- 
 ings of sheet-iron, tin, or zinc, with same letter 
 references as in Fig. 3723. 
 
 These portables may be used to warm stores or 
 buildings where it is not convenient or desirable to 
 erect brick walls, and may be placed in basements 
 or cellars, warming the rooms in which they stand, 
 if need be, as well as those above. They have 
 sufficient power to warm a moderate sized building, and can be removed as easily as a common stove. 
 
 Fig. 3275 represents a portable furnace with two metal coverings, with the inlets and outlets of cold 
 and hot air, smoke-pipe, &c., w’ith evaporating pan standing upon the top of the drum. 
 
 3726. 
 
 McGregor’s hot-air furnace. — Fig. 3726 is a front view of largest furnace set in mason- work. 1, feed 
 door; 2, fire-chamber; 3, 4, and 5, hot-air pipes; 6, ash-pit door ; 7, cold-air box; 8, cylinder chamber 
 for generating hot air. 
 
 Fig. 3727 exhibits an internal view of the structure of the furnace. A C D, the course of the heat 
 ascending into the drum, descending Aid passing off into the smoke-pipe. H, the feed-door for fuel, 
 D, the back damper by which the fire is checked by admitting cold air into the smoke-pipe. 
 
 The aim of this furnace is to exclude entirely the red and unwholesome heat made by the hot or fire 
 chamber, in which the coal is burnt, from coming into the hot air chamber, and instead, all the heat is 
 thrown into the large cylinder drum in the air-chamber, which is never allowed to become so heated ae 
 
WARMING AND VENTILATION. 
 
 811 
 
 to burn the air ; and into this chamber is continually allowed to pass a large volume of fresh air, and 
 from thence into the apartments. The serious objection to furnaces has been, not that they would not 
 produce sufficient heat, but that the air was burnt and poisoned by coming in contact with the red-hot 
 cylinder as it passed through the hot-air chamber, which in this furnace is obviated by shutting off in a 
 separate brick chamber all the heat thrown out from the cylinder. 
 
 Walker's hot-air furnace for heating and ventilating dwellings, churches, school-houses, d'c . — Walker’s 
 hot-air furnace is now very much in vogue, and we extract from his treatise on warming as follows : 
 
 The principle of heating by hot-air furnaces is to take fresh air from outside the building, warm it, 
 and then let it flow into the rooms as temperature and ventilation require. Thus, a pipe conducts the 
 air from outside of the building to the air-chamber of the furnace, i. e., the space inclosed about the fur- 
 nace ; here it is warmed, and is then conducted by pipes into the apartments, while the smoke and gas 
 generated by the combustion of the fuel pass off by another pipe to the chimney. 
 
 But if the air-chamber and the pipes leading from it are small, or if the furnace itself is so small that 
 in order to get the heat required its surface must be kept at a high red-heat, a furnace will be found to 
 be one of the most expensive and disagreeable modes of heating. To construct a good furnace, there- 
 fore, several things must be considered. 
 
 1. Ventilation . — The problem is how to • secure a pleasant, genial heat, with thorough ventilation. 
 Either of these alone may be very easily and economically obtained. Stoves of various kinds will pro- 
 duce heat at little cost, but they afford no ventilation. Open doors and windows will produce ventila- 
 tion, but at the expense of that warmth which health and comfort require. 
 
 To make a furnace the means of ventilating an apartment does not appear to have been thought of. 
 The uniform plan was to admit into the apartments to be warmed by the furnace but a small quantity 
 of air, which, to produce sufficient heat, was necessarily raised to a very high temperature— intensity of 
 heat being substituted for quantity. This was in various ways productive of bad results. The small 
 volume of air introduced into a room from the air-chamber of the furnace was worth very little for 
 ventilation. 
 
 But the question arises, how is the requisite amount of ventilation to be secured ? What limit shall 
 be assigned to the introduction of fresh air into an apartment which is to be heated to a given temper- 
 ature ? The answer to this question must vary with the relative importance of economy in fuel, and of 
 the health and comfort of the occupants of the room. The limit of the amount of ventilation must 
 sometimes be that which can be afforded. The heating of air for this process is just so much fuel 
 thrown away. 
 
 The most economical stove is that which is placed in the room to be warmed, and the smoke of which 
 is reduced to the temperature of the room ; if no change of air then take place, by crevices or otherwise, 
 we have arrived at perfection in the economy of fuel. Whether it is advisable to practise such econo- 
 my, or rather parsimony, for this is its nature, is quite another question. It is upon this principle of the 
 non-renewal of the air and low temperature of the smoke, that air-tight stoves consume but little wood ; 
 that the odor of the rooms warmed by them, in which several people are assembled, is offensive, and 
 their influence upon the health injurious. In New England the winter temperature is such that the 
 expense of heating up the air to a comfortable point is a serious item, and the temptation to economize 
 in this respect is with some not easily resisted. 
 
 If pure and healthy air be worth what it will cost, then should hot-air furnaces be so constructed as 
 to admit freely large quantities of fresh air into the apartments. But while this object is secured, fur- 
 naces should be so constructed also that the ample volume of air thus freely introduced shall be raised 
 to the required temperature with the least possible expense of fuel. 
 
 2. Evaporation . — There appears to be a great ■want of information on this branch of the subject, even 
 among those who ought to be sufficient masters of their business to know its use. Thus one man will 
 advertise as a recommendation of his furnace, that “ a large quantity of water is evaporated, to restore 
 to the air the oxygen taken from it by the heat of the furnace.” Another has a furnace “ so constructed 
 that evaporation is not necessary, as it never becomes sufficiently hot to destroy the vitality of the air,” 
 it being lined with soap-stone, or something similar. 
 
 But all such statements are based upon an incorrect idea of the use of evaporation. They imply that 
 heat destroys the vitality of the air, and that the evaporation of water will restore it, neither of which 
 is correct. Heat without combustion does not destroy the vitality of the air ; and if it did, evaporation 
 would not be a remedy. The necessity for evaporation arises wholly from the fact, that as the temper- 
 ature of the air is increased, its capacity to hold and its tendency to absorb moisture are increased also. 
 Thus a given volume of air at the temperature of 40 deg. is capable, like a sponge, of holding in suspen- 
 sion a certain quantity of water. If now, without adding to the quantity, the temperature be raised to 
 65 deg., the capacity for moisture is nearly doubled ; if raised to 90 deg. it is nearly quadrupled ; and 
 if additional moisture is not supplied by the evaporation of water, what may be termed, for convenience, 
 the drying powers of the air will be manifested in its effects upon the wood-work of the apartments, 
 upon the furniture, and also upon the skin and lungs of the occupants. It is impossible, therefore, to 
 contrive a heating apparatus which shall dispense with the necessity for evaporation. The laws of 
 nature require this expedient, to supply air at an increased temperature with the moisture which it 
 demands. 
 
 But evaporation, important as it is, must be judiciously conducted. The evaporating pan should have 
 a large surface, and should be so arranged that the water shall never be heated to the boiling point. 
 When water boils, steam will rise whether the air requires it or not ; but when the water is below the 
 boiling point, evaporation proceeds in some measure according to the wants of the air. When the air is 
 very dry the evaporation is rapid, and when moist it proceeds slowly. In a dry day a number of gal- 
 lons will be evaporated, while in a very moist state of the atmosphere, when the same amount of heat 
 is required, the evaporation is scarcely perceptible. If nature is consulted in arranging this department 
 vf the furnace, the supply of moisture will always be regulated by the demand. 
 
S12 
 
 WARMING AND VENTILATION. 
 
 3. Temperature . — To keep the apartments at a comfortable temperature, well ventilated, without dust 
 or gas, and without injury to furniture or to health by the extreme dryness of the atmosphere, in a 
 word, to keep up a continual supply of pure, fresh, invigorating air at summer heat, is the desideratum 
 in a hot-air furnace. To effect tins the heat must be imparted by a surface so large that no part of it 
 wall be highly heated in obtaining the requisite temperature. The chief objections against furnace? 
 have arisen from the fact that very small surfaces have been used, and were heated to such a degree 
 that the innumerable particles of animal and vegetable matter that are always floating in the air were 
 burned, rendering the air offensive and unhealthy. The air also was very highly heated, which not only 
 made it very unpleasant, especially when it came in contact with the person before its temperature was 
 reduced, causing headache, lassitude, and other disagreeable sensations, but also very injurious to the 
 Dannels and other wood-work of the room, furniture, &c.. by reason of its extreme dryness. 
 
 When the temperature of the air cannot be diminished ■without depositing water upon the walls of 
 the containing vessel, or appearing as a mist, it is said to be saturated. If the temperature of saturated 
 air be raised, it will, to the feelings, become drier, and will immediately begin to take up water which 
 is exposed to it ; air is dry or mo>«t, not in proportion to the water it contains, but in proportion as it b 
 more or less removed from the point of saturation. 
 
 3728. 
 
 Walkers patent improved hot-air furnace, manufactured at No. S9J Leonard-street, New York, is 
 represented in Figs. 3728 and 3729. 
 
 The objects aimed at by the patentee in the construction of his hot-air furnace are — 
 
 1st. By means of one tire to produce a mild, uniform, and agreeable temperature throughout several 
 apartments, and to warm a whole house sufficient for sleeping-rooms, or to keep plants of all kinds in 
 the coldest weather. 
 
 3729. 
 
 2d. To avoid all dust and gas, and to keep the apartments well ventilated by means of a constant 
 supply of fresh air from without. 
 
WARMING AND VENTILATION. 
 
 81 .: 
 
 8d. To be simple, so that any one capable of managing a stove can take care of it. 
 
 4th. To be economical in point of fuel. 
 
 5th. To be durable, so as not to require frequent or expensive repairs. 
 
 The furnace is constructed of cast-iron, is placed in the cellar and inclosed in brick walls, in such a 
 manner that there is very little heat wasted by escaping into the cellar or chimney-flue. Consequently 
 all the fuel consumed is made available to heating the apartment ; and in no case where they have been 
 erected, have they failed to give entire satisfaction. 
 
 A, upper smoke-pipe. 
 
 B, damper. 
 
 C, drums, or radiators. 
 
 D, feed-door. 
 
 E, fire-pot, fluted. 
 
 F, cold-air flues. 
 
 Literal References. 
 
 G, space between walls for cold air. 
 
 H, hot-air flues. 
 
 I, lower smoke-pipe. 
 
 J, evaporating pan — 12 gallons. 
 
 K, door to put in or take out the heater. 
 
 L, door to remove ashes. 
 
 We extract from the Journal of the Franklin Institute a report on warming and ventilating the west 
 half of the Lunatic Asylum of Blockley Almshouse, Philadelphia, by steam : 
 
 Much difficulty was experienced in the adaptation of an old edifice, not originally designed for such 
 a system as has been adopted, and which added greatly to our labor and made it more difficult to effect 
 our purpose. 
 
 In constructing the heating chambers and necessary flues, we were obliged to cut through a system 
 of arches, which, on account of the substantial manner in which the building was constructed, added 
 greatly to the expense and time attending the prosecution of the work. The want of proper flues and 
 conduits for the warmed and extracted or foul air, all of which we were obliged to construct, or alter to 
 answer the purpose of the present arrangement; the insufficient height of the cellar ceiling for our pur- 
 poses, and the impossibility of going any deeper on account of water, presented another serious difficulty 
 in the great distance the steam had to be convoyed and the condensed water returned again to the 
 boilers, being 600 feet; a greater depth would have facilitated the return of the condensed water. 
 
 Running underneath the building are a number of sewers, into which the sinks are drained, conse- 
 quently making them very foul. These made a system of ventilation very desirable, but at the same 
 time greatly interfered with our efforts to produce a pure atmosphere throughout the building. The 
 building itself is one very difficult to warm, on account of the great height of the ceilings, the first story 
 being 14 feet 11 inches, the second 16 feet 4 inches, and the third 14 feet 8 inches in height. The 
 number and large size of the windows making the glass surface equal to 3447 square feet, and the im- 
 perfect fitting of the windows, together with the large size of the doors, and the very exposed situation 
 of the building, render it, perhaps, more difficult to warm than any of the buildings connected with the 
 Institution. 
 
 Explanation of the figures. — Fig. 3730, plan of building, and warming and ventilating. 
 
 Fig. 3731, elevation of heating chambers. 
 
 Fig. 3732, longitudinal vertical section of the arrangement for warming and ventilating. 
 
 Fig. 3733, plan of a part of the heating and ventilating chamber. 
 
 Fig. 3734, elevation of Fig. 3733. 
 
 Fig. 3731 is a plan of the west half of the Lunatic Asylum : the main building, running east and west, 
 is 168 feet long by 69 feet wide, inside measurement, three stories high, with an attic. On each floor 
 of the main building there is a large hall running the length of it, a stairway, kitchen, dining-room, and 
 three large associate rooms, in each of which there is a nurse’s room, wash-room, and water-closet. 
 
 The wing at right angles to the main building is 119 feet long by 46 feet wide, inside measurement, 
 three stories high, with an attic. On each floor of the wing there is a hall running the length of it, and 
 connected with the main building by another hall, two stairways, a nurse’s room, a bath-room, two asso- 
 ciate rooms, and twenty cells. 
 
 Great pains have been taken to procure air for the supply of the house from pure sources, and to keep 
 it from being contaminated while in the equalizing and heating chambers under the building. The ar- 
 rangements are such that the patients cannot interfere with them in any way ; there are no valves in 
 any of the flues except those in the hall, nor have they been found desirable, as there is but a trifling 
 difference in the temperature of the different parts of the house, thus avoiding the consequent annoyance 
 from interference with them. 
 
 The heating chamber A A, for warming the main building, runs along the centre of the cellar 
 until within 23 feet of the wing, where it was found necessary to stop, on account of a sewer 
 crossing it at right angles. For warming the halls in the main building, another chamber B is con- 
 structed. For warming the cells and halls in the wing, the heating chamber A' runs the length of the 
 wing at right angles to the main chamber. For warming the associate find nurse's rooms, the chambers 
 A" A" A” are constructed. 
 
 The air for supplying the main building is drawn from the garden on the south side into equalizing 
 chambers L L L, and from thence through the small apertures OOO, Ac., in the bottom of the chamber 
 wall, as indicated by the arrows, Fig. 3733, into the heating chamber A where it is heated, and then 
 distributed through the flues F F F, Figs. 3732, 3733, and 3734, into the different parts of the house to 
 be warmed. 
 
 The air for supplying the cells and halls in the wing is drawn from the inclosure on the west side of 
 the building. It is received into a shaft S sufficiently high to be beyond the reach of the patients who 
 may be exercising in the yard, conveyed down this and through a tunnel 50 feet in length into the 
 heating chamber A', where it is heated, and from thence distributed into the cells and halls. 
 
 The associate rooms in the wing receive their supply of air from the garden, and the nurse’* room* 
 
«14 
 
 WARMING AND VENTILATION. 
 
 from the yard. Their arrangements for the equalizing and heating chambers, flues, Ac., are the same as 
 the others. 
 
 The arrangements by which the heated air is introduced and the foul air extracted from the rooms, 
 will be understood by referring to Figs. 3732, 3733, and 3734, which represent the arrangement for 
 warming and ventilating three of the large associate rooms in the main building, which are each 47 by 
 44 feet. The flues F F F lead from the heating chamber A to near the ceiling in the centre of the 
 rooms ; these supply the heated air for warming- the roo™' throwing it out in the directions as inchoated 
 by the arrows. 
 
 The foul air is drawn off by means of the foul-air flues Y V placed in the sides of the rooms, opposite 
 to the entrance for warm air ; they open close to the floor, thus producing a downward ventilatioa 
 Through these it is conducted to the main foul-air flue K K, Figs. 3733 and 3734 ; from thence conducted 
 to the extracting shaft E, which is 90 feet high, fitted with a cast-iron chimney 30 inches diameter 
 and 25 feet high, through which the smoke and gases from the fire are discharged. The extracting 
 shaft is also fitted with a steam-jet, by means of which additional force can be given to the ventilation 
 if it should be desirable. There is also a small furnace in the base of the shaft, so arranged as to pro- 
 duce ventilation when the heating apparatus is not in use. 
 
 The main sewer which runs under the building is so connected with the fire under the boiler that the 
 necessary air for supplying the furnace may be drawn from it, thus creating a current of air into the 
 sewer, and in a measure preventing the escape of fetid gases. 
 
 GG, Figs. 3730 and 3731, are two cylindrical boilers, 86 inches in diameter and 40 feet long, having 
 a capacity, together, equal to 565 cubic feet. We would here assure j t ou of the perfect safety of these 
 
WARMING AND VENTILATION. 
 
 815 
 
 boilers. They are constructed of tire best Pennsylvania iron, by experienced workmen, and are of un- 
 usual thickness; the heads, although of cast-iron, are concave; the boilers weigh together 12,186 lbs., 
 the great amount of water they contain, and consequently the amount of time necessary to evaporate 
 it, makes them safe as regards explosion from the most frequent cause, the want of water ; and their 
 proportion in relation to the fire and radiating surfaces is such that, were the safety-valves chained 
 down, it would be impossible to generate a pressure of 100 lbs. to the square inch. With the present 
 weight at the extreme end of the safety-valve levers, 72 lbs. pressure would raise them. The boilers 
 will sustain a pressure of 300 lbs. to the square inch without any danger ; 30 lbs. is the greatest pressure 
 under which the apparatus is generally worked. Plain cylinder boilers are always preferable to tubu 
 lar boilers where there is room enough to make them sufficiently large — they can be made stronger on 
 account of their form ; they have, also, more steam and water room. The boiler of a first-class locomo- 
 tive of ordinary construction will generate enough steam, when the fire is in full operation, to fill the 
 steam space in four seconds, and enough, could there none escape, to burst the boiler in about ten min- 
 utes ; they will evaporate the water so as to become dangerous in from 30 to 60 minutes when the 
 supply of water is stopped. 
 
 3732. 
 
 3733. 
 
 The smoke and gases from the furnace are conveyed through the smoke flue D, Figs. 3730 and 3731, 
 within the heating chamber A, until it is opposite the extracting shaft E ; from here it is conducted 
 across and into the cast-iron chimney P, within the extracting shaft E. The smoke-flue within the heat- 
 ing chamber A is covered with cast-iron plates, and these with clean sand. The arrangements are such 
 that the temperature of the smoke and gases is reduced below 200 deg. Fahr. before they are permitted 
 to escape, thus preventing any unnecessary waste of heat, and consequently of fuel. 
 
 To the boilers are connected, by means of a 6-inch cast-iron main R, systems of radiating pipes li li h 
 of wrought-iron, f inch inside diameter ; they are distributed through the different heating chambers 
 A A' A", <fec. These systems are so arranged that the condensed water is returned to the boilers to be 
 again converted into steam, thus producing a circulation. There are between 8000 and 9000 feet of 
 radiating pipe distributed through all the heating chambers. 
 
 If a rapid circulation through the radiating 
 pipes is desired, for the purpose of raising the 
 temperature of the building in a comparatively 
 short time, it is effected by opening a blow-otf 
 cock which discharges into a sewer; or by 
 means of a steam-pump, so arranged as to take 
 the water from the condensed water pipes and 
 force it into the boilers. This pump is also used 
 for supplying the boilers with water when the 51 
 pressure of steam is too great to do so from the 
 reservoir. 
 
 In the third story of the wing is an iron tank, 
 of a capacity of 1200 gallons, in which the water 
 for washing and bathing purposes is heated by 
 means of a coil which is supplied with steam from the boilers GG,a distance of 200 feet. 
 
 The boilers also supply the steam for cooking the food for the inmates. In the kitchen are two 
 boilers of 95 gallons each, and one of about 50 gallons ; in these the food is cooked. The k'tchen in the 
 
* 
 
 816 WARMING AND VENTILATION. 
 
 eastern or male part of the house is arranged in the same way. They are all supplied with steam from 
 the same source. 
 
 There is no fire in the west half of the Asylum excepting under the boilers G G, and a small cooking 
 stove for preparing food for the sick. 
 
 The cubical contents of the building warmed, without deducting partition walls, stairways, <fec., is 
 *780,000 cubic feet ; the amount actually warmed by the apparatus, deducting partition walls, stairways, 
 <fcc., is 730,000 cubic feet, or 90 rooms and 6 halls. 
 
 The consumption of fuel in cold weather is 1-J tons of coal per day, (24 hours ;) allowing 75 days cold 
 and 100 days moderate weather through the winter, the consumption would be 213 — say 225 tons; 30 
 tons of this should be deducted,- which is the amount used in cooking, and 15 tons of this should be 
 charged to the eastern or male part of the house. The consumption of fuel, as near as we can ascertain, 
 for heating this part last year by close stoves, (fee., and there was no ventilation, was from 275 to 300 
 tons of coal, say 275 tons, when but a portion of the rooms were warmed, and that imperfectly ; while 
 by the arrangement introduced by us, the whole of the building is warmed at a saving of at least 75 
 tons of coal, which, at $4 per ton, would be $300. 
 
 The advantages of the present arrangement are — 
 
 1st. Producing a pure atmosphere throughout the building, the air being supplied in great abundance 
 from pure sources, and so arranged as to keep it from contamination. 
 
 2d. A system of downward ventilation, which diffuses the warmth uniformly throughout the various 
 apartments ; the air being admitted near the ceiling and drawn off at the floor is constantly sinking, and 
 in this way the colder and impure air passes off by the foul-air flues, and is ejected from the extracting 
 shaft above the building. 
 
 3d. The safety from fire, both in the building and as regards the patients, which, in a lunatic asylum, 
 is a very important consideration. 
 
 4th. The freedom from noise, dust, and dirt usually attendant upon fires in grates and stoves. 
 
 5th. The whole heating arrangement being under the care of a single individual, is more easily man- 
 aged than by a number of attendants, who are now dispensed with. 
 
 6th. The economy of the arrangement, saving about 25 per cent, in fuel ; the repairs will not exceed 
 those of stoves and grates. 
 
 Ventilation. — The following hints on ventilation will be found of value in this place ; they are by 
 W. Walker, Engr., of Manchester. 
 
 However useful steam agency, as applied to ventilating purposes, may be in factories or buildings 
 connected with them, and in theatres or other places liable to great and sudden influx or efflux of per- 
 sons — and well as it has been found to answer in its appplication to other buildings, such as club-houses, 
 banks, collegiate institutions, and hospitals, in which manifest advantages have been derived from its 
 employment — there will still be great numbers and many classes of edifices in which it would be 
 from various causes inadmissible. Churches, chapels, and houses for worship, may be enumerated under 
 this head — the numbers contained within their walls being, on the whole, tolerably constant, and not 
 liable to very sudden fluctuations ; but especially from the circumstance that they are seldom used more 
 than two days in the week, with intervals of two or three days between ; and when used it is only for 
 two hours consecutively, with intervals of two or three hours between. With such proper quantity and 
 sizes of ingress and egress flues as can readily be obtained in the thick walls and piers of such edifices, 
 (if planned prior to their construction,) this short period of occupation will not permit their atmosphere 
 to become very highly charged with impurities, while the intervals between the services will be found 
 sufficient for an entire change of the whole atmosphere left in them at the close of each service, without 
 resorting to mechanical means. In churches with lofty open roofs, of the mediceval or early English 
 construction, without galleries, the total cubic space bears so large a proportion to that portion of it 
 occupied at the floor level by the congregation, that scarcely any injurious vitiation of the entire atmos- 
 pheric contents can take place during the short period of occupation, provided moderate preparations 
 have been made for ingress and egress. Hence, very sudden and powerful ventilation is scarcely re- 
 quired in such churches, and the purification of their atmosphere may safely be left to the spontaneous 
 action of those preparations ; but on special occasions, and in hot weather, the action of the fresh-air 
 flues may be accelerated by the exhausting power of a shaft or trunk of adequate size running up within 
 the tower or steeple, its upper end discharging into the external air, while its lower end communicates 
 with the interior by openings in or near the roof ; and this shaft may be made, in very hot weather, to 
 perform two or three times its usual duty, by rarefaction produced at its lower end g, Fig. 3735, by a 
 large number of gas-burners fixed there in tolerably close proximity with each other, and supplied with 
 gas from the mains which furnish light to the whole building. These ideas have been successfully car- 
 ried out in numerous instances, and in large buildings. The whole process recommended for such a 
 building will be better understood by a reference to the upper portion of Fig. 3736, which represents a 
 section of a church ventilated in this manner ; a a are openings all round the church for admission of 
 fresh air ; b b, hot-water pipes, over which it is made to pass on its way to the gratings cc; dd are 
 openings, by which the vitiated air enters a horizontal trunk e, from the end of which rises the shaft f 
 with a collection g of gas-jets in the bottom of it; h i is the gallery line, and k an excavated room for 
 the boiler, the floor of which should be five feet below the floor line of the church. 
 
 By simply turning the cock in the gas-pipe which supplies the jets, the rarefaction in the shaft, and, 
 consequently, the velocity and quantity of the air passed through the church, may be controlled with 
 tolerable accuracy, and instantly proportioned to any greater or smaller number of persons assembled. 
 The cost of piping and cock for bringing the gas to the jets has been found to be but trifling ; and as 
 they need oidy be lighted during the time the church is occupied for worship, which is seldom of longer 
 duration than two hours and a half, the consumption of gas is not very great, and amply compensated 
 by the beneficial result obtained. 
 
 The means most proper to be adopted for the plentiful supply of fresh air in the low-roofed, galleried 
 
WARMING AND VENTILATION. 
 
 811 
 
 and crowded meeting-house, will be found to consist in abundance of fresh-air openings all round under 
 the windows, communicating by brick flues with the lower part of the spaces under the aisles and seat® 
 in which the hot-water pipes that are to warm the air should be fixed. Fresh-air flues should be con- 
 structed in all the piers between the windows, running as high as the gallery, to supply it with fresh 
 warmed air. A vitiated air-flue should also commence in each pier under the gallery (in order to give 
 free egress to that which would otherwise be intercepted and detained under the gallery) and pass up 
 into a horizontal trunk, running over the roof, along each side, into the foot of the upright shaft below 
 the gas-jets, as before explained. Openings should also be left in the roof, communicating with these 
 horizontal trunks, to carry off the bad and heated air over the galleries. Hot-water pipes should be 
 conveyed along the side-walls, under the floor, so as to warm the air that passes up within the piers intc 
 the gallery. 
 
 The leading points to be observed in such a case are delineated in the lower part of Fig. 3735, below 
 the line h i. 
 
 A much larger provision should be made for supplying fresh air to such a house for worship, or other 
 galleried building, than in one which has no gallery, and which possesses the advantage of an open roof ; 
 and those who would object to the copious measures here recommended as unnecessary, should well 
 consider the following facts and calculations. A chapel or meeting-house with large galleries nearly 
 all round, capable of accommodating on special occasions 2000 persons, is frequently made about 75 feet 
 square and 25 feet average height, givfing a total cubic content of rather more than 140,000 feet. Now 
 the authorities from Tredgold to Reid who have written on the subject of the quantity of fresh air re- 
 quired per minute by each individual, to replace that which such individual has rendered unfit for res- 
 piration, vary in their conclusions from 3^ to 10 cubic feet; and if 7 cubic feet be assumed to be the 
 proper quantity, an allowance near the average of their scientific opinions will be given. The total 
 quantity required, therefore, on this low standard in such a building, to maintain its atmosphere in a 
 state of purity when filled, will be (2000 X 7 =) 14,000 cubic feet every minute, and a like quantity ol 
 vitiated ah' must be carried off in the same time. The atmosphere of the building will therefore require 
 to be completely changed or renewed (140,000 -f- 14,000 = 10) once in every ten minutes. Let it now 
 be supposed that the unusual provision of 16 openings has been made all round the building for fresh 
 air, each opening measuring 18 inches by 6 inches. Deducting one-third of the area for impediment 
 caused by gratings, will allow to each opening a clear area of half a superficial foot, and the aggiegate 
 area of all the openings will be eight feet. Now, to supply the required quantity of air (14,000 cubic 
 feet) in the given time (one minute) through these openings, the air must pass through them all at the 
 velocity of (14,000 8 =) 1750 feet per minute, or more than 20 miles per hour : which it will not do, 
 
 especially on a calm day in hot weather, when ventilation is most needed , without the aid of some pow- 
 erful stimulus ; and if such artificial impulse be wanting, these openings will, under the circumstances, 
 be quite insufficient to prevent the rapid deterioration of the atmosphere within, and ought, therefore, 
 to be considerably enlarged. The bad effects of the usual way of obtaining a partial supply of air in 
 such a case by opening the windows, have been already commented on. 
 
 Take another example from a larg« Gothic church, with galleries and lofty side-aisles and nave, in 
 the neighborhood where this is written ; measuring 80 feet by 65 feet, with a roof approaching to flat- 
 Vol. II.— 52 
 
818 
 
 WARMING AND VENTILATION. 
 
 ness, about 30 feet in average height. This church has often contained 1800 persons ; its cubic contentG 
 being 156,000 feet, and the requirement of air, allowing, as before, seven feet per minute to each person, 
 (1800 X 7 =) 12,600 feet. The time in which the whole atmosphere of this church would, when con- 
 taining its full complement of persons, require to be changed, is (156,000-1-12,600=) 12-J- minutes ; 
 and large openings will obviously be required to pass the quantity in the time. 
 
 These figures will suffice to show the necessity for a very much larger provision for ventilation than 
 has been customary in buildings containing galleries, in which the cubic contents bear a small propor- 
 tion to the numbers assembled. 
 
 The management of the warming of a church being a matter frequently intrusted to a sexton or verget 
 charged with other duties, which necessitate his making a clean appearance, and demand his exclusive 
 attention during the service, it is a matter of some importance, where hot-water apparatus are used, to 
 adopt such form of boiler as will require the smallest possible attention. The kind shown in Fig. 3736, 
 in section, will be found to fulfil this requirement. In this, a is the fire-box ; b, ash-box ; c, smoke-box ; 
 d, fire-bars ; e, smoke-tubes ; f fuel-box ; g, damper ; h, flow or steam pipe ; i, return or condensation 
 pipe ; j, ash-box door ; k, fire-door ; /, smoke-pipe. Many large churches have been kept by it at a uni- 
 form temperature with only three attendances in twenty-four hours. This sort of boiler will be found 
 very desirable in many other buildings besides churches. They are to be filled to the top with coke 
 broken into small pieces, which falls on the fire as required. A very useful kind of Arnott stove has 
 icei largely adopted on the same principle. 
 
 3730. 
 
 The stove here described appears to us a very simple arrangement for effecting the purposes desired, 
 and to be well worthy of adoption. 
 
 In the whole raDge of ventilation there is, perhaps, nothing so much neglected as the ventilation of 
 schools ; and as it is most desirable public attention should be turned to the subject, we give room to 
 Mr. Walker’s statement of his views on the subject : 
 
 Schools are frequently very crowded, and their atmosphere in a most unwholesome condition. The 
 great increase in their number in the populous manufacturing districts, is a gratifying sign of the times, 
 and affords good reason to hope that the succeeding generation will grow up with improved ideas and 
 habits, and, as is most needful in those districts, stand some degrees higher than their predecessors in 
 the scale of civilization. 
 
 Fig. 3737 is a section representing a boys’ and girls’ school ventilated (except as regards the windows) 
 in a satisfactory manner : a a are the fresh-air openings ; b b, pipes for heating ; c c, gratings for entrance 
 of fresh warmed air ; d d, openings for foul air, leading into a trunk e, whence it is drawn down the shaft 
 f by the rarefying furnace g , whence it is discharged up the shaft h into the atmosphere. 
 
 This arrangement of a rarefied shaft, continued down to the ground for the purpose of obtaining a 
 quick draught by a heated column, and requiring a down-shaft to connect the ventilating trunk from the 
 top of the building with its lower end, so that the foul air may enter it below the fire, is the same that 
 has been adopted, at very great cost, by Dr. Reid, in the new houses of Parliament. There is a com- 
 plexity and expense about this arrangement which would seem to be needless. The drawing down to 
 the ground level of the whole of the vitiated air of the building, and then sending it up again ; the cost 
 of connecting the main down-shaft with the up-shaft, which circumstances may require to be at a con- 
 siderable distance ; and the trouble of forming air-tight connecting-flues to convey the vitiated air from 
 numerous rooms to one main down-shaft, to say nothing of the double space and materials occupied by 
 (he two shafts, w ould render this plan in numerous cases impracticable. To overcome some of these 
 
WARMING AND VENTILATION. 
 
 819 
 
 difficulties tlie fire has, in many cases, been provided for at the roof level, (i, Fig. 3737,) thus relinquish- 
 ing the down-shaft and the lower part of the up-shaft, and so far has been an improvement ; but in 
 many cases the trouble of carrying up fuel and ascending to attend to the fire was too great, and the 
 ventilation was, therefore, uncertain. The best mode of effecting forcible ventilation by a shaft doubt- 
 less is, to adopt the last-named arrangement ; substituting gas rarefiers for a furnace, as shown in the 
 church, Fig. 3735. By bringing the pipe which supplies gas to the burners to some accessible point 
 near the ground-floor, with a stop-cock at that point, the handle of which should work in a graduated 
 quadrant, the ventilation can be regulated from below with great precision. 
 
 Window ventilation of a kind very frequently adopted in churches and schools, has been introduced 
 into this figure, (. Tc , Fig. 3737,) not with a view to represent it as part of Dr. Reid’s system, but to illus- 
 trate its bad effects, either where it is the sole provision made, or where it is used in combination with 
 a better process. If it be the sole provision made, and the room be heated by a fireplace or stove to 
 B0°, a downward rush of air at 10° (should that low temperature happen to prevail outside at the time) 
 will play upon the heads of those near it. If it be in force, as in the figure, simultaneously with proper 
 means of introducing fresh warmed air, its force will be modified, and partially deflected upwards, towards 
 the egress openings ; but whatever cold air thus enters is so much deducted from that which ought to 
 have entered warmed through the proper channel c. 
 
 Arnott's ventilating apparatus in use in the York County Lunatic Asylum, England. — The apparatus 
 is shown in the annexed engravings, of which Fig. 3738 is a plan, and Fig. 3739 a section, taken through 
 the centre from A to B. It consists of a fixed cylinder, placed in the centre of a room, and which cyl- 
 inder is about 5 ft. 6 in. diameter and 5 ft. high, with a chamber above and below, each furnished with 
 inlet-valves to receive the air from the fresh-air shaft, and crtlet-valves to deliver the air into the adja- 
 cent chamber, and thence distributed through the building. The cylinder is made of galvanized iron, is 
 
 3738. 
 
 >pen at both ends, and has an outer case at about 3 inches distance, and the whole depth of the cylin- 
 der filled with water, which forms an annular hydraulic joint. Within this cylinder is another cylinder, 
 5 ft. 9 in. diameter, inclosed on the top, similar to the rising bell of a gas-holder ; the rim of this cylinder 
 works up and down in the water contained in the annular rim just described. By this arrangement the 
 communication with the upper and lower compartments is cut off. 
 
 The working cylinder is suspended to the end of a movable beam about 10 feet long, and balanced 
 by a weight or bob suspended at the other end, equal in weight to the movable bell, minus a sufficient 
 
WATCHMAKING. 
 
 8’dO 
 
 weight to cause the bell to descend and expel the air in the lower compartment. Now, for the purpose 
 of setting the beam in motion, it is necessary to have some movable power to overcome the friction 01 
 the movable parts and the air. For this purpose Dr. Arnott has adopted a single-action water-engine, 
 having a cylinder 2 inches diameter and 12 inches stroke; to be supplied by water from a reservoir 
 placed on the top of the building, 60 feet above the engine. A column of water of this altitude acts 
 with a pressure of about 30 lb. on every movable square inch of the piston ; and if the piston be 2 
 inches diameter, it will be equal in round numbers to 3 square inches, consequently the force of the 
 water acting on the piston will be 3 X 30 = 90 lb. ; and this is the power with which the Doctor pro- 
 poses to work the apparatus, and as the engine is single-acting, the cylinder will require about a pint 
 of water for every stroke. Thus, if the engine works 8 strokes per minute, it will require 8 pints of 
 water, or 1 gallon per minute, to keep the beam moving. 
 
 This engine is placed so that the connecting-rod is connected with the movable beam at 1 foot from 
 the fulcrum ; and if the beam have a radius of 5 feet, and the working cylinder be suspended at the end 
 of the beam, the bell will be elevated 5 feet at every stroke of the engine. When the piston has per- 
 formed one upward stroke by the pressure of the water, the water is cut off by a slide-valve, and that 
 which is within the cylinder is discharged into an open pipe ; consequently, the extra weight of the 
 movable parts will cause the piston to descend, and at the same time the working cylinder will also 
 descend. Now, if we suppose that at the commencement of the working of the apparatus the working 
 cylinder is close down on to the fixed cylinder, the upper compartment will be filled with air, and as it 
 rises it will displace a quantity of air equal in capacity to the cubic contents of the working cylinder, 
 and force it out of the valves that open outwards ; and at the same time that the cylinder is rising, the 
 space below is increasing equal in capacity to the cylinder, and a quantity of air rushes in through the 
 valves opening inwards, and fills up the space ; and when the bell begins to descend, the lower inlet- 
 valves close and the lower outlet-valves open, and the air that is below is forced out through the outlet- 
 valves of the lower compartment, and at the same time the air is being admitted into the upper com- 
 partment, as before described. By this means the action is double, and a constant stream of air is being 
 taken in through either of the inlet-valves, and forced out through the upper or lower outlet-valves into 
 the adjacent chamber, and thence through trunks and cases to all parts of the building. 
 
 Now, it has been shown that for every stroke of the engine the working cylinder displaces a quantity 
 of air equal to its capacity in both the bottom and upper compartments ; and as the capacity of the 
 working cylinder is equal to 125 cubic feet, it displaces in both compartments 250 cubic feet for every 
 upward and downward stroke of the engine, at an expense of one pint of water, descending from an 
 altitude of 60 feet ; and if the engine works 8 strokes per minute, it will displace 2000 cubic feet of air 
 at an expense of 8 pints, or one gallon of water, which is equal to 2,880,000 cubic feet of air displaced 
 by the aid of 1440 gallons of water for 24 hours. These are the proportions proposed by Dr. Arnott for 
 ventilating York Hospital. 
 
 For the purpose of feeding the apparatus, pure air is brought down a shaft, the top of which is con- 
 siderably above the top of the building, and which communicates at the bottom with the chambers be- 
 fore described ; and if it be desired that the air be warmed, it is effected by allowing the air, as it is 
 expelled from the chambers on its passage to the trunks, to pass between a series of hollow copper ves- 
 sels filled with hot water. 
 
 The adaptation of the water-engine which Dr. Arnott proposes to adopt is particularly desirable, as 
 it can be worked at comparatively little expense, and the water, after it has done its work in the en- 
 gine, may be used for domestic purposes. It will also be seen that by this apparatus the whole of the 
 air forced in for ventilation can be accurately measured if a counter be attached to the engine to show 
 the number of strokes the engine has performed during the day. 
 
 Literal references. — Similar letters refer to similar parts in each figure. 
 
 A is a fixed cylinder, open at both ends with outer case a, filled with water, forming an annular hy- 
 draulic joint. 
 
 B, working cylinder inclosed on the top and open at the bottom ; the rim works up and down in the 
 hydraulic joint a. 
 
 C C', upper and lower chambers, with inlet-valves i v opening inwards to take in the air from the ex- 
 ternal air-shaft E ; and outlet-valves o v opening outwards to convey the air to the shaft D, and thence 
 to the building through the trunk T. 
 
 F, furnace-room, in which is placed the boiler with four square fire-boxes////, to heat the water for 
 supplying the copper cells g, when it is required to warm the air as it is being forced into the building ; 
 there are several of these copper heating cells placed side by side, with narrow spaces between for the 
 air to pass through. 
 
 H, a water-engine, acted on by a column of water on one side of the piston, which is brought by a 
 pipe h from a cistern placed on the roof 60 feet above ; j is an air-vessel to prevent concussion by cut- 
 ting off the water suddenly ; k, geer for opening and shutting the eduction and induction valves ; l, pis- 
 ton and connecting-rod. 
 
 K, balance-beam ; at one end is fixed a chain to suspend the working cylinder, and at the other end 
 is another chain to suspend a balance-weight m. 
 
 WATCHMAKING, or Horology — the construction of instruments for the measurement of time. 
 The most satisfactory of the ancient instruments for the measurement of time, was the Clepsydra or 
 water-clock ; in which the hours were indicated by marks upon the side of a vessel filled with water, 
 from whose bottom a small stream was allowed to flow out. As the water in the vessel ran off, its 
 surface sank ; and its height, as shown by the marks, indicated the time that had elapsed. It was soon 
 found that the water does not run from such an orifice with a regular velocity ; for, when the vessel is 
 full, the pressure of the fluid is much greater than when it is nearly empty, and its flow will be pro- 
 portionally faster. 
 
WATCHMAKING. 
 
 821 
 
 The simplest mode of overcoming the difficulty, arising from the unequal flow 
 of water through an orifice in the bottom of a vessel, is shown in Fig. 3*740. This 
 clepsydra consists of a cylinder of glass, furnished with a float a , which carries the 
 siphon h. When this siphon has been once filled with water, the fluid will run 
 out at the cock c, until the whole water in the vessel has been drawn off. The 
 rate at which the water is discharged may be regulated by the cock c ; and as, by 
 the connection of the siphon with the float, the mouth of the pipe is always at the 
 same distance below the surface of the water, the quantity will always be the 
 same, whatever be the height of the fluid in the vessel ; and a scale d, on its side, 
 divided into equal parts, will always indicate, by the place of the float, the lapse 
 of equal intervals of time. 
 
 All these instruments, however, were but rude attempts to effect that which is 
 at present accomplished far more perfectly by other means. By the combination 
 of wheel-work (acting upon principles already described) with the pendulum, 
 the laws of whose vibration have also been explained, clocks rre now constructed, 
 which indicate the passage of time with a degree of accuracy which it would have 
 been thought but a short time since quite impossible to attain. It is to these in- 
 struments that the term Clock is- now restricted. A watch is a portable instru- 
 ment, in which the same mechanism is employed as in the clock, but in which, 
 instead of a pendulum, there is a balance-wheel, whose vibrations are regulated 
 by a spring. Any clocks or watches might be termed chronometers or time-measurers ; but this name 
 is now appropriated to those which are constructed with the utmost attention to the perfection of every 
 part, and with means for compensating certain errors to which they are liable. The most perfect clocks 
 are those constructed for astronomical observations, in which the greatest possible accuracy is required ; 
 and hence these are ordinarily termed astronomical clocks. It must be borne in mind, however, that 
 these differ from ordinary clocks in no essential particular; though their appearance is often puzzling 
 to those who see them for the first time, in consequence of the hour and minute hands being fixed on 
 distinct centres, and pointing to different circles, instead of revolving about the same centre, and point- 
 ing to the same circle, as in ordinary clocks. Again, the most perfect watches are those constructed 
 for the purposes of navigation, to which they give the most important assistance ; and these, being 
 much larger than ordinary watches, though constructed on the same principle, are distinguished as ma- 
 rine chronometers. 
 
 General principles — Moving and regulating powers. — The object of clock-work is to maintain the os- 
 cillations of a pendulum, by continually communicating to it a slight additional impulse ; and, at the 
 same time, to register the number of these oscillations, so as to indicate the passage of time. In order 
 to effect these purposes, a train of wheels and pinions is put in motion by a power acting on the first 
 of them, whilst the last is connected with the pendulum by a peculiar contrivance, termed the escape- 
 ment. In clocks which are to remain stationary, and in which a saving of room is no object, the moving 
 power is a weight, which is suspended by a string coiled round a drum or barrel ; this drum carries 
 the first wheel of the clock, and imparts to the train the movement it derives from the gradual descent 
 of the weight. If the whole of this force acted on the wheel-work alone, which it would do if the es- 
 capement were taken off, the weight would run down comparatively fast, and the train would be caused 
 to move with great rapidity. But a part of it is expended in keeping up the vibrations of the pendu- 
 lum ; and the connection of this with the wheel work is such, that not a tooth of the latter can advance, 
 unless permitted to do so by the swing of the pendulum. Hence a clock will not go, even when wound 
 up, unless the pendulum be set in motion ; but when its vibrations have once commenced, they will 
 continue until the string has been unwound from the barrel by the descent of the weight. In “ winding 
 up" the clock, we raise the weight by again coiling its string round the barrel ; and thus communicate 
 (as it were) to the machine a power which will keep it in action for a certain limited time. It would 
 not be difficult to extend that time, to any desired amount, by adding to the number of wheels. Ordi- 
 nary watches, and the commonest kinds of clocks, require to be wound up every day ; chronometers 
 for ships, and house-clocks, are commonly made to go without winding for a week ; many clocks have 
 been constructed which only required winding once a month ; and a few have been made to go for a 
 year. It will be easily understood, upon the principle of the wheel and pinion, that the greater the 
 multiplication of velocity, the greater will be the sacrifice of power ; so that, the longer a clock is made 
 to go — or, in other words, the more slowly its weight is made to descend — the greater must be the 
 power required to produce the same effect ; and the weight must therefore be increased in the same 
 proportion. 
 
 In small portable clocks, however, and in watches and chronometers, a weight cannot be thus em- 
 ployed ; and motion is given to the wheel-work by means of a spring, made of elastic steel, and coiled 
 in a spiral. One end is secured to a fixed point ; and the other, in the effort to uncoil itself, will carry 
 round any thing to which it may be attached. Now it is easy to understand, that a spiral spring, in 
 uncoiling itself after having been tightly wound, exercises a much greater degree of force than it will 
 do when it has become slackened ; and therefore, if the spring were immediately connected with the 
 wheel-work, the impulse which it would give to the train would be much greater at the beginning than 
 at the end of the action. An attempt has been made, in France, to correct this inequality, by making 
 a variation of strength in different parts of the spring itself, so that it shall unwind with equal force, 
 whether it be tight or slack ; and if this can be effected, the spring may be made to act at once upon 
 the first wheel of the train, as shown in Fig. 3746, where O P is the spring, of which the outer end 0 is 
 fixed, so that the inner end, being fixed on the axis or spindle of the wheel N, carries this round in its 
 effort to uncoil itself. But it is found impossible to make such a correction with sufficient accuracy ; 
 and a different method is generally adopted. 
 
 The spring is inclosed within a hollow barrel or drum, to which its outer end is attached ; and the 
 
 37 4C 
 
822 
 
 WATCHMAKING. 
 
 3741. 
 
 
 inner or central end of the spring is attached to a fixed axle. Hence, when the spring has been coiled 
 up, its elasticity will carry round the barrel, in its attempt to uncoil itself. The barrel, in turning round, 
 pulls a chain, which was previously coiled round a conical axle, 
 which is termed the fusee. This axle carries along with it the first 
 wheel of the train. In winding up the watch, we coil the chain 
 round the fusee, and draw it off from the barrel ; by which action 
 the spring within the barrel is coiled up and its power becomes 
 very strong. In attempting to uncoil itself, it pulls the chain, which 
 now acts upon the small part of the fusee. When it has gradually 
 uncoiled itself, the power of the spring is weakened ; but by this time nearly the whole of the chain is 
 coiled upon the barrel, having been unwound from the fusee ; and its pull or strain acts upon the large 
 part of the fusee. Now upon the principles stated in a former part of this work, the more distant 
 the point to which a force is applied from the central axis, the greater will be its power of giving 
 the required motion. When the spring is acting most strongly, therefore, its power is applied at a far 
 less mechanical advantage than when its power is nearly exhausted ; and thus its action on the spindle 
 of the fusee is equalized, so that from a variable power it is made to become nearly as regular as that 
 produced by the descent of a weight. 
 
 The contrivance by which, in winding up a clock or watch, we can turn the fusee 
 without influencing the wheel- work, is shown in Fig. 3742. The first wheel is hol- 
 lowed out to receive the small ratchet-wheel d, of which the teeth are so cut as to slant 
 on one side, but to be upright in the other. In the same hollow, there is a movable 
 click or ratchet b, which is pressed down by the spring c. Now if the ratchet-wheel 
 be turned in the direction of the slanting sides of its teeth (that is, from left to right 
 in the accompanying figure) it will not carry the large wheel with it ; fur the ratchet 
 will be lifted by the inclined side of each tooth, and will consequently pass over them 
 all. But if the ratchet-wheel be made to turn in the contrary direction, it will carry 
 the large wheel with it ; for the upright side of the tooth will be caught by the ratchet ; so that any 
 force applied to the ratchet-wheel will act upon the ratchet, and consequently upon the large wheel 
 with which it is connected. Now the fusee is attached to the ratchet-wheel; and hence, when the fusee 
 is being drawn by the chain in the direction last mentioned, it carries round the large wheel with it, 
 and gives motion to the whole train ; whilst, if the fusee be turned in the contrary direction, as it is by 
 the key in the act of winding, the teeth of the ratchet-wheel lift the ratchet, and there is no motion 
 given to the large wheel. The same contrivance is applied in clocks, to the drum round which is coiled 
 the string that suspends the weight. In the better class of time-keepers, whether clocks or watches, 
 there is another contrivance introduced into the fusee, by which the train of wheels is kept in motion 
 during the time when the weight or spring is being wound up ; so that the inaccuracy that would be 
 tfnerwise occasioned by the stoppage of the movement (which any one may observe, who notices the 
 *econd-hand of an ordinary clock or watch, whilst it is being wound up) is prevented. This contrivance 
 is termed the maintaining power or going-fusee. 
 
 Having now considered the moving power, by which the train of wheels is kept in action, we shall 
 examine the regulating power, by which its action is controlled. This, in all clocks now constructed, is 
 the pendulum ; whilst in watches and chronometeus, it is a wheel termed the balance. The balance of 
 a watch serves the same purpose as the pendulum, having the advantage of occupying much less space, 
 and of acting equally well in almost any position. It consists of a wheel, having an axle which ter- 
 minates in two very fine pivots, and so exactly balanced, as to be capable of being moved with a very 
 small impulse in either direction. To the axle, however, is attached one end of a very delicate spiral 
 spring ; of which the other end is attached to the frame-work of the watch, as shown in Fig. 3747. Now 
 the action of this spring is like that of any other elastic body ; it will produce a certain degree of re- 
 sistance to any change of position of the balance ; and the greater the alteration of its place, the greater 
 will be the resistance, until at last the force which set the balance in motion is overcome by it, and the 
 rotation ceases. But the spring has been so much displaced, that it tends to bring the balance back to 
 its original position, with a gradually increasing rapidity ; and when it has arrived there, the force 
 which it has acquired will carry it as far on the other side. Again this force is resisted by the spring, 
 and again will this bring back the balance to its former position. 
 
 Thus a balance, provided with a spring that possesses perfect elasticity, and uninfluenced either by 
 friction or the resistance of the air, would go on vibrating backwards and forwards without cessation. 
 But three retarding influences really act upon it — want of perfect elasticity in the spring, so that each 
 reacting force is somewhat less than the force which acted on it ; friction of the pivots ; and resistance 
 of the air. Hence, in order to keep up these vibrations, it is necessary that a slight additional impulse 
 should be continually given to the balance, as to the pendulum. When a balance is well constructed, 
 its vibrations become almost perfectly isochronous, whether the space through which it moves be long or 
 short ; hence it is not much affected by moderate differences in the strength of the impulses given to it 
 by the moving power, and in this respect has even advantages over the pendulum. It is found advan- 
 tageous to construct the balance-spring of the best chronometers not in the form of a flat spiral, like 
 that of the common watch, shown in Fig. 3747, but in that of a helix or cork-screw, as shown 
 in Fig. 3743. And the balance itself is not a complete wheel, but is made in a peculiar 3 ~ 4 3. 
 
 form, which will be described hereafter, for the purpose of compensating the influence of L _j=hi 
 
 heat or cold upon the spring. The time occupied by each vibration of the balance depends 
 upon the strength of the spring — other things being supposed equal; and the strength is in- 
 fluenced by the length. A short spring, of equal thickness with a long one, is very much 'w 
 more elastic; hence, by shortening the balance-spring, we increase its elastic force ; whilst 
 by lengthening it, we diminish that force. The greater the elastic force, the shorter will be the vibra- 
 tions of the balance, and the less will be the time occupied by each of them ; consequently the time- 
 
WATCHMAKING. 
 
 828 
 
 piece will gain when the spring is shortened, and will lose when its length is increased. It is by 
 slightly altering the length of this spring that a time-keeper is regulated, so as to go faster or slowe’ 
 than before. 
 
 The contrivance by which the pendulum or the balance is connected 
 with the moving power, is termed the escapement. The simplest form 
 of this is represented in Fig. 8714. Let xy be the axis on which the 
 balance turns, or from which the pendulum is suspended ; projecting 
 from it in different directions are two leaves c and d, which are termed 
 pallets. At fb is seen a crown-wheel, turning on a perpendicular axis 
 oe; its teeth are cut like those of a saw ; and the direction of its move- 
 ment is from right to left, — that is, / moves towards b, whilst on the 
 further side i moves towards a, and a comes gradually round to f. 
 
 This wheel, termed the balance-wheel, is connected with the rest of the 
 movement by the pinion on its axis, as will be shown hereafter. The 
 pallets are so placed, with regard to the teeth of this wheel, that, as 
 the axle turns from one side to the other by the swinging of the pen- 
 dulum or the vibrations of the balance, the teeth are permitted to 
 escape alternately from each of them, and thus the wheel turns round 
 with an interrupted motion. In the figure, the pendulum or balance is 
 represented as at the extremity of its excursion towards the right, and 
 the movement of the axis has just allowed the tooth a to escape from 
 the pallet c ; whilst at the same time the tooth b is just about to fall 
 on the pallet d. Now, whilst the pendulum or balance is moving to 
 the left, that is, from p to g, the tooth b still presses against the pallet 
 d, and is prevented by it from moving further on, until the pallet has 
 changed its position so far towards the left, as to allow the tooth to 
 escape from it. During all the time that the tooth is pressing against 
 the pallet, the balance-wheel is communicating to the pendulum or 
 balance, through its means, a part of the power by which it is itself moved ; and thus supplies the im- 
 pulse required to keep its vibrations up to the proper extent. When the tooth b has escaped from d, 
 the tooth i, on the other side of the wheel, will drop against the other pallet c; and will remain press- 
 ing against it, in like manner, until the return of the pendulum or balance to the position represented 
 in the figure lifts the pallet c sufficiently to allow the tooth i to escape from beneath it, as a had pre- 
 viously done. In this manner, then, the wheel is allowed to advance by an interval of half a tooth at 
 each vibration of the pendulum or balance; and thus, if the wheel have 15 teeth, and the pendulum 
 vibrate seconds, it will make one revolution in half a minute.* 
 
 This escapefnent was in use long before either the pendulum or balance-spring was applied to the 
 regulation of time-keepers. 
 
 The escapement first used to connect the pendulum with the clock, precisely resembled that which 
 has just been described. The axis of the crown-wheel was vertical, as in Fig. 3744 ; and the pendulum 
 was attached to the horizontal axis x y. In fact, there was no essential variation from that representa- 
 tion, except that, instead of a cross-bar with weights p and q at either end, the lower portion only, x p, 
 was left, to serve as a pendulum. It was found, however, that the extensive vibrations which a pen- 
 dulum must make when so hung were injurious to the regular going of the clock ; and various contriv- 
 ances have been devised to prevent this source of error, by constructing the escapement in such a man- 
 ner that the pendulum shall make shorter vibrations. These have completely superseded the use of 
 this original escapement (termed the crown-wheel and verge ) in clock-work ; but it is stdl used in 
 watches, where, indeed, it is an object to make the vibrations of the balance as extensive as possible. 
 All ordinary watches are constructed upon this plan ; and they are distinguished as vertical watches, 
 because the last crown-wheel has a vertical or upright position, as seen in Fig. 3745. 
 
 The first watches that were made were as imperfect as the early clocks ; and differed only from them 
 in being made upon a smaller scale, and in the use of a spring instead of a weight, as the moving power. 
 They had only an hour-hand ; and most of them required winding twice a day. The invention of the 
 spiral balance-spring followed the application of the pendulum to the clock, at no long interval ; and 
 thus both machines were made to receive the greatest possible improvement in the principles of their 
 construction, at a very short interval. The honor of this invention is claimed by Huyghens, the A’obe 
 Hautefeuille, a Frenchman, and Dr. Hooke. There can be little doubt that it is really due to the last 
 of these ; for he was able to produce proof that he had employed the balance-spring, and had applied 
 for a patent for his invention, in the year 1658 ; whilst the claim of Huyghenswas not made until 1674. 
 
 Construction of ordinary watches and clocks . — The general construction of an ordinary watch will 
 now be explained. That of a clock is precisely the same, whether it be large or small ; with the ex- 
 ception of the substitution of a weight and barrel for the mainspring and fusee. On opening an ordi- 
 nary watch-case, we see that the wheel-work is for the most part contained between two round plates, 
 which are connected together by pillars. One of these plates is attached to the dial ; but there is a thin 
 space between them, which is occupied by the wheel-work that connects the motion of the hour and 
 minute hands. On the other plate is a raised portion, beneath which the balance works. 
 
 A general view of the work of a common watch, as seen from the side, is shown in Fig. 3745. For 
 convenience of display, the parts are all arranged in one line, instead of being disposed in a circle at 
 they really are ; and, in order to make them more distinguishable, the distance of the two plates, be- 
 tween which most of the work is contained, is much increased ; as is also the space between the upper 
 
 3744. 
 
 * A crown-wheel of this kind must always have an odd number of teeth ; else the teeth on the opposite sides would norae 
 against the pallets at the same time. 
 
824 
 
 WATCHMAKING. 
 
 plate and the dial, which really lie close together. The balance is seen at A ; and on its axis or spindle are 
 the two pallets p p, which together constitute what is termed the verge. At C is seen the balance-wheel, the 
 teeth of which resemble those of a saw. By the vibrations of the balance, the teeth of this wheel are per- 
 mitted to escape from each of the pallets alternately, as already explained. On the axis of the bal- 
 ance-wheel is a pinion d, which is driven round by the crown-wheel K. This wheel is termed by watch- 
 makers the contrate-wheel. On the axis of this last is a pinion c which works into the third-wheel L; 
 and the axis of the third-wheel is another pinion b which works into the wheel M, termed the centre- 
 wheel, from its position in the centre of the watch, (see Fig. 3746, e.) The axle of this wheel passes up 
 through the centre of the dial, and carries the minute-hand; making one complete revolution in an 
 hour. Upon this axle is placed the pinion a which works in the great-wheel N. This wheel is acted on 
 by the mainspring, which is either fixed upon its own axis, as represented at 0 P in this figure, or is 
 contained within a barrel or circular box, which acts by means of a chain upon the f usee which carries 
 the great-wheel, as already explained. Upon the axis of the centre-wheel, between the upper plate 
 and the dial, is fixed the pinion Q; and this drives the wheel T. Upon the spindle of this wheel is a 
 pinion g which works into the wheel Y. The axis of this last wheel is hollow, so as to allow the axis 
 of the centre-wheel to pass up through it ; and upon this hollow spindle the hour-hand is fixed. 
 
 Z~io. 
 
 It ! s seen, then, that in the watch, as in the clock, the moving power acts on a wheel which drives a 
 pinijn ; that this pinion carries on its axis awheel, which drives another pinion carrying another wheel ; 
 and so on. Hence there is a continual increase of velocity, and at the same time a loss of power. The 
 revolution of the balance-wheel c is very rapid in proportion to that of the great-wheel N, but its force 
 is less in the same proportion ; so that the slightest interruption (such as a thickening of the oil on the 
 teeth and pivots) is sufficient to check the movement of the former, whilst the power of the latter, com- 
 municated to it by the spring, is sufficient to overcome a considerable resistance. 
 
 Many different trains may be adopted, to give the required proportions between the times of revolu- 
 tion of the several wheels ; since their rates depend not upon their absolute number of teeth, but upon 
 the proportion between the teeth of the wheels and the leaves of the pinions. The centre-wheel must, 
 of course, make one revolution in an hour ; the balance-wheel is generally made to turn 94 times in a 
 minute ; whilst the great-wheel makes one revolution in about four hours ; so that, if the spring can 
 turn it seven times round, the watch will go for 28 hours. The following is the train (or arrangement 
 of the number of teeth in the wheels and joinions) usually adopted in common watches. The great- 
 wheel N has 48 teeth, and the pinion a into which it works has 12 teeth ; consequently this pinion will 
 make four revolutions whilst the wheel revolves once ; and if the great-wheel turn round in four hours, 
 the centre-wheel will make one revolution every hour. The centre-wheel M has 54 teeth, and the pinion 
 b has 6 leaves ; so that it, together with the third-wheel, turns round nine times, whilst the centre-wheel 
 revolves once, and hence makes nine revolutions in an hour. The third-wheel L has 48 teeth, and the 
 pinion c has 6 leaves, so that the velocity is again multiplied by 8 ; and the contrate-wheel which is on 
 the axis of the pinion c will make (8X9) 72 turns in an hour. The contrate-wheel K also has 48 teeth, 
 and the pinion d into which it works has 6 teeth, so that a further multiplication of velocity takes place, 
 to the amount of 8 times ; and the balance-wheel C, which is carried round by the pinion d, turns 
 (72X8) 576 times in an hour, or about 9-J times in a minute. The balance-wheel 0 has 15 teeth, and 
 naif of one of these escapes with every turn of the balance ; hence there are about (94X15X2) 305 
 impulses given to the balance in a minute, so that each of its vibrations occupies 60-305th parts, or about 
 l-5th of a second. 
 
 It is often an object, however, to cause the fourth or contrate wheel to revolve exactly once in a 
 minute ; so that its spindle may carry a hand which shall indicate seconds on the dial. This may be 
 done by making the balance perform exactly five beats in a second, and by giving 15 teeth to the bal- 
 ance-wheel, 6 leaves to its pinion, and 60 teeth to the contrate-wheel. The contrate-wheel, in turning 
 once round, causes the balance-wheel to revolve 10 times ; and hence the number of escapes its teeth 
 will make is (10X15X2) 300 in a minute, or one in every fifth part of a second. Or the balance may 
 be adjusted to beat nine times in two seconds ; and then the number of teeth in the contrate-wheel must 
 be nine times that of the pinion it turns — that is, 54 to 6, or 63 to 7. Or the number of beats may be 
 four in a second ; and for this arrangement the contrate-wheel must have eight times the number of 
 teeth in the pinion it turns — that is, 48 to 6, or 54 to 7. When the contrate-wheel is to be thus made 
 to turn 60 times in an hour, instead of 72, (as in the ordinary train,) the number of teeth in the centre- 
 wheel and third-wheel, and the number of leaves in the pinions they tun}, must be regulated accord- 
 
WATCHMAKING. 
 
 825 
 
 ingly. The usual plan is to give the centre-wheel 64; teeth, and to the pinion it turns 8 leaves ; so 
 that this pinion, carrying with it the third-wheel, revolves eight times for each turn of the centre-wheel 
 The third-wheel, having 60 teeth, works into a pinion of 8 leaves ; and this last, carrying the contrate- 
 wheel, turns 7-J times for each revolution of the third-wheel. Hence the contrate-wheel turns (8X7T) 
 60 times for each revolution of the centre-wheel ; and as the latter makes one revolution in an hour, so 
 does the former complete one in each minute. 
 
 3746. 3747. 
 
 llm mode in which the parts of a watch are actually arranged is shown in ? r. 3746, representing the 
 interior of a watch, from which one of the plates has been removed, seen from above. Here a is the 
 barrel, containing the mainspring coiled within it. By the elasticity of this, the barrel is made gradu- 
 ally to wind upon itself the chain b, which was previously coiled around the fusee, and thus to give mo- 
 tion to that fusee, which carries round with it the great- wheel c. The pinion turned by the great-wheel 
 is seen at d ; and this carries on its axis the centre-wheel e. It is the spindle of this wheel which, pro- 
 longed through the dial, carries the minute-hand. The wheel e turns the pinion f which carries round 
 the third-wheel g; and this works into the pinion (which cannot be shown is this view) that carries 
 round the contrate-wheel h. This wheel turns the pinion i, which carries round the balance-wheel- k. 
 The balance itself and the verge are supposed to have been removed with the upper plate, which is 
 shown separately in Fig. 3747. This gives a view of the back of the works of an ordinary watch, as 
 seen when the case is opened. The balance is seen at p ; its spiral spring is shown by s ; and the end 
 of this is fixed at t. In order to regulate the length of this spring, so as to bring the vibrations of the 
 balance precisely to their required number in a minute, there is a movable piece, marked o, through a 
 slit in which the balance-spring passes. This piece (which is termed the curb) can be made to travel 
 towards one side or the other, by means of a wheel acted on by the circular scale r, to which the key 
 is applied for the purpose of regulating the watch. The position of the curb o determines the acting 
 length of the balance-spring, since the part between o and t is cut off, as it were, from the rest. Hence, 
 if the curb be moved towards t, the acting length of the spring is increased •, whilst, if it be moved away 
 from t, the spring is shortened. The effect of this alteration 
 has been already explained. At q is seen the square end of 
 the spindle of the fusee, to which the key is applied for wind- 
 ing the chain off the barrel. In Fig. 3748 is shown the work 
 which lies between the dial and the plate on which it rests, 
 having for its object to give motion to the hour-band. The 
 wheel x is turned by a pinion on the axis of the centre-wheel, 
 concealed in this figure by the wheel v, but shown at Q in Fig. 
 
 3745. The wheel x carries round with it the pinion w, which 
 gives motion to the wheel v ; and on the hollow spindle of 
 this last the hour-hand is fixed. The number of teeth in these 
 wheels and pinions must be so proportioned, therefore, that the 
 wheel v shall turn round with only l-12th of the velocity of 
 the central axis. Thus, suppose the centre-pinion to have 15 
 teeth, and the wheel x to have 60 teeth, the latter will only 
 revolve once whilst the former revolves four times. Again, if 
 the pinion w have 20 teeth, and the wheel v have 60 teeth, the 
 wheel v will turn round once whilst the pinion w revolves three 
 times, and the central pinion (3X4) 12 times. 
 
 It is not exactly correct to say, however, that the central pinion and the minute-hand are fixed upon 
 the spindle of the centre-wheel ; for if they were, the hands could not be moved without turning the 
 centre-wheel, and we should not be able to set them, without disturbing the whole movement of the 
 vratch. I here is a very simple provision for permitting this to be done. The pinion and minute-hand 
 are fixed, not to the axis of the centre-wheel, but to a hollow spindle which is fitted upon this, and car- 
 ried round by friction, so long as there is no opposing resistance. When we set the watch, however, the 
 central axis remains unmoved, and we merely turn round the hollow spindle which carries the minute- 
 hand and the pinion. This pinion acts upon the wheel x, which, through the pinion w and the wheel y, 
 turns the hour-hand one-twelfth of the amount that the minute-hand has been moved ; and thus the two 
 are always made to turn conformably to each other whether they be carried round bv the going of thy 
 
 3748. 
 
820 
 
 WATCHMAKING. 
 
 watch, or by the action of the key in setting it. If the face of any ordinary watch 1 e examined, thert 
 will be seen a small round spindle projecting in the centre. This is the spindle of the centre-wheel 
 Inclosing this is the first hollow spindle, which carries the minute-hand, and which is squared at the 
 top to receive the key ; and this is again inclosed in a second hollow spindle, to which the hour-hand is 
 atl ached. These are seen in Fig.- 37-15. Precisely the same means are adopted to connect the motion 
 of the two hands in ordinary clocks ; but where great accuracy is required, as in clocks used for astro- 
 nomical observations, it is desirable to avoid unnecessary friction as completely as possible. This is done 
 by making the hour-hand turn on a different centre from the minute-hand ; and the former receives its 
 motion from the latter, by means of a wheel containing 12 times as many teeth as the pinion which 
 turns it, and therefore making its revolution in 12 times the period. In astronomical clocks, however, 
 the hour-circle is not unfrequently divided into 21 parts, instead of 12; and the hand requires a whole 
 day and night to traverse it. The object of this is to avoid any mistake, arising from the same numbers 
 being repeated twice between noon and noon, or midnight and midnight. Some clocks have been con- 
 structed, especially at Venice, to strike all the numbers, from 1 to 21 ; but in this there can be no ad- 
 vantage. 
 
 The mechanism of a portable, eight-day clock is represented in 
 Fig. 3719. Of the two barrels, fusees, and trains of wheel-work 
 here seen, the one on the right-hand side alone has for its office the 
 measurement of time. The other is called the striking-train, and 
 its office will he separately considered. The works are arranged, as 
 in the watch, between the plates, in which are holes for the pivots of 
 the axles of the various wheels, <fcc. The front plate is attached to 
 the dial, with an interval in which the hour-hand movement is con- 
 tained, as in the watch. This interval also contains the mechanism 
 by which the striking is regulated. The dial and the front plate are 
 supposed to be here removed, so as to give an uninterrupted view of 
 the train of wheels. The back plate is shown by the letters ABCD. 
 
 The springs inclosed in the barrels E E give motion to the fusees F F, 
 as in the watch, either by a chain or a piece of catgut. The main- 
 wheel a of the going-train has 96 teeth, and this acts on the centre- 
 wheel pinion k, having 8 leaves. This pinion carries with it the cen- 
 tre-wheel b ; and on the same spindle, as in the watch, the minute- 
 hand is placed. The centre-wheel b acts on the pinion l ; and this 
 carries round with it the third-wheel c. This third-wheel, in its turn, 
 acts on a pinion (not seen in the engraving) which carries round the 
 scape-wheel <7; and this wheel, acting on the pendulum by the pal- 
 lets n o of the escapement, communicates to it the impulse received 
 from the spring, whilst its own motion is entirely determined by the duration of the vibrations of the 
 pendulum. For if, on the very same escapement, we were to hang a pendulum of 9f inches, another of 39 
 inches, and another of 13 feet, the duration of each beat, and consequently the interval between the escape ot 
 each tooth, would be half a second in the first pendulum, a second in the next, and two seconds in the last. 
 
 The number of teeth in the wheels and pinions, therefore, must depend upon the length of the pen- 
 dulum. Thus, for a pendulum vibrating seconds, the number of teeth in the scape-wheel is usually 
 30, since, as the wheel only advances to the amount of half a tooth at each escape, its revolution is then 
 performed in a minute, and it may be made to carry a seconds-hand. If the centre-wheel and the third- 
 wheel have 64 and 60 teeth respectively, and their pinions have 8 leaves, the multiplication of velocity 
 will be (60 X 64 ~~ 8 X 8) exactly 60 ; so that the scape-wheel will turn round 60 times for one revolution 
 of the minute-hand. Where the pendulum vibrates half-seconds, however, it would be necessary to 
 make the scape-wheel with 60 teeth, if it be required to perform but one revolution in a minute. Small 
 portable clocks, however, such as those designed for a table or mantel-piece, are not made with a sec- 
 onds-hand ; and in these the scape-wheel is made with a small number of teeth, and revolves in a shorter 
 time ; the number of teeth in the wheels and pinions which connect it with the centre-wheel being ad- 
 justed accordingly. In a clock now before the author, the centre-wheel has 84 teeth. This turns a 
 pinion of 7 leaves, which must therefore revolve 12 times as fast, or once in every five minutes. This 
 pinion carries round with it the third-wheel, which has 77 teeth in it ; and the latter drives the scape- 
 wheel by a pinion of 7 leaves, so that a velocity of 1 1 'to 1 is gained. The scape-wheel goes round, 
 therefore, 1 1 times in five minutes, or once in somewhat less than half a 
 minute. It has 32 teeth ; and the pendulum, being not quite eight inches 
 • ong, allows each to escape in rather less than half a second. 
 
 Clock-escapements.- — The construction of the anchor-pallet escapement, 
 
 To called from its having some resemblance to an anchor,) which is 
 now applied to nearly all ordinary clocks, is seen in Fig. 3750. The 
 scape-wheel has its teeth cut upon its edge, and not raised up as they 
 are in the scape-wheel of a verge watch. The centre, from which the pen- 
 dulum is suspended, is seen at A; and the same point is the centre of mo- 
 tion of the piece of metal ABC, which is termed the crutch, the extremi- 
 ties B and O being the pallets. This crutch is usually not fixed to the pen- 
 dulum, since it is convenient to detach the latter, when the clock is to be 
 moved from one place to another ; but it is so connected with it, that, as the 
 pendulum swings from side to side, the two ends of the crutch move up 
 and down. The position of the crutch shown in the figure is that which cor- 
 responds with the direction A E of the pendulum. If the pendulum be 
 jarried to A F, the end B of the crutch would be raised still more ; whilst if it swing to the other sid" 
 
 3750. 
 
 3749. 
 
WATCHMAKING. 
 
 827 
 
 A. F', the end B of the crutch would sink between the teeth of the scape-wheel, whilst the end C would 
 be raised quite clear of them. The scape-wheel is driven by its pinion in the direction of the arrows ; 
 but its motion sutlers interruption by the alternate locking and disengagement of its teeth against the 
 pallets of the crutch ; and as the movements of these depend upon the pendulum, its time of vibration 
 regulates the period in which the wheel revolves. 
 
 In the position of the escapement shown in the figure, the pendulum is to be supposed to be at E, 
 and to be moving towards F. Now the elevation of the pallet B, against whose under side tooth 5 -was 
 previously pressing, has disengaged the point of that tootli ; and the scape-wheel is consequently at 
 liberty to move onwards. But it is prevented from doing so to more than the interval of half a tooth ; 
 for whilst the pallet B was being withdrawn from the space between 5 and 6, the pallet C was sinking 
 into the interval between 2 and 3 ; consequently the wheel's revolution is checked by the fall of the 
 point of tooth 2 against the upper surface of the pallet 0. But as the pendulum continues to swing to 
 F, the pallet C is still further lowered ; and it gives a slight backward impulse to the tooth which was 
 resting upon it, and consequently to the whole wheel. This backward movement, termed the recoil, 
 may be seen in the seconds-hand of any common clock; this hand being attached to the scape-wheel, 
 and carried round with it. Having completed its swing to F, the pendulum begins to move back again, 
 and in doing so it is assisted by the pressure of tooth 2 against the upper surface of the pallet C. This 
 pallet is gradually withdrawn from the tooth that rests upon it, so that this at last escapes. But in the 
 mean time the pallet B has sunk into the interval between 5 and 4 ; so that when tooth 2 has escaped 
 from the pallet C, tooth 4 drops against the under side of pallet B. The further motion of this pallet, 
 which continues until the pendulum has reached the position F', again causes the recoil of the wheel ; 
 but when the pendulum begins to swing back towards B, it is again assisted by the moving power of 
 the wheel, which tends to make the tooth 4 (now resting on pallet B) press that pallet towards the 
 left. When the pendulum lias moved to E, tooth 4 escapes, as 5 had done before ; and tooth 1 falls 
 upon the pallet 13, as 2 previously did ; tooth 5 having in the mean time moved on to 6, and tooth 
 2 to 3. 
 
 The objection to the recoil escapement consists chiefly in this, that the impelling power of the weight, 
 communicated through the train of wheels, is acting on the pendulum, by means of the inclined surfaces 
 of the pallets, during the whole of each of its vibrations. Hence, any inequalities in the moving power 
 are liable to produce a considerable effect on the pendulum, so as to vary its rate of vibration ; and such 
 inequalities are continually liable to occur from various causes. It was to avoid this source of error that the 
 dead-beat escapement was invented by Graham, a celebrated cloekmaker at the commencement of the last 
 century, to whom we owe also the invention of the mercurial pendulum. The peculiarity of this escape- 
 ment consists in the form of the pallets ; the surface of each of which is partly a circle, having the point 
 of suspension for its centre, and partly an inclined plane. The construction and action of this escape- 
 ment are seen in Fig. 3751. The centre of suspension is at A ; whilst A B and 
 A C are the two legs of the crutch, moving from side to side with the vibra- 
 tions of the pendulum, whose line of direction is shown by A D. The scape- 
 wheel moves in the direction shown by the arrow ; and the position of the 
 whole is seen to be such in Fig. 3751, that the pendulum having nearly 
 reached the limit of its vibration on the left hand, the tooth 6 has escaped 
 from the pallet B, having just slid off the inclined portion of its surface, of 
 which the dotted line b shows the direction. The tooth 2 now drops against 
 the pallet c, and the further motion of the scape-wheel is thereby checked. 
 
 The pendulum then begins to vibrate towards the right, carrying with it the 
 crutch; so that the pallet B enters the interval between the teeth 5 and 6; 
 whilst the pallet C is drawn out from the interval between 1 and 2. During 
 this movement, however, the scape-wheel remains at rest ; for so long as the 
 tooth 2 bears upon the circular part of the pallet C, it does not either ad- 
 vance or recede, and its moving power is not communicated to the pendu- 
 lum. But as soon as the pallet G has been sufficiently withdrawn for the Dl 
 
 edge of. the tooth 2 to press against the inclined plane, of which the dotted 
 
 line c is a continuation, the wheel is allowed to move forwards ; and it communicates an impulse to the 
 pendulum, which aids it in its vibration. 
 
 When the pallet C has been completely withdrawn by the continued motion of the pendulum, the 
 tooth 2 is entirely disengaged from it ; and the wheel would move onwards, but for the check it re- 
 ceives on the other side. Whilst the pallet C was being withdrawn, the pallet B was entering the 
 interval between 5 and 6 ; consequently, just as the tooth 2 is disengaged from the former, tooth 5 falls 
 upon the upper surface of the latter. 
 
 The pendulum, having completed its vibration towards the right, commences its return ; and whilst 
 it is moving in that direction, the tooth 5 remains at rest, and the whole wheel is consequently 
 stationary, until the pallet B has been withdrawn far enough for the tooth to rest against tbo inclined 
 portion of its surface. When it does so, the wheel again begins to move onward, and gives the pendu- 
 lum a fresh impulse, in a contrary direction to the first. When the pallet B shall have been completely 
 withdrawn, and the pendulum have arrived at D, the tooth 5 will be disengaged, and will take up the 
 position of the tooth 6 in Fig. 3751. 
 
 Hence, during a large part of each vibration of the pendulum, the scape-wheel is stationary, in con- 
 sequence of the resting of its teeth upon the circular portion of the pallets ; and it is only whilst they 
 are sliding down the inclined plane, which action occupies but a small proportion of the whole time, 
 that the wheel moves on. Its movement, therefore, as indicated by the seconds-hand, is a succession 
 of jerks, very different from the recoiling movement of the scape-wheel of the ordinary clock. As the 
 dead-beat escapement is the one now universally adopted in this country for the best kind of clocks 
 whether those designed for astronomical purposes or for regulators of time, (such as almost every watcb 
 
WATCHMAKING. 
 
 8-28 
 
 3752. 
 
 maker possesses,) and also in many large public clocks, most of the readers of this description may ob 
 tain the opportunity of observing its action. 
 
 Compensation pendulum. — Although every part of a clock may be constructed with the greatest per- 
 fection, its performance will be very inaccurate, unless it be provided with the means of compensating 
 for those changes which result from an alteration of temperature. A very minute difference in the 
 length of a pendulum will produce a decided influence upon the rate of going of a clock. For if this 
 alteration be so trifling as to cause an increase or decrease of the time of each vibration by l-1440th 
 part of its whole length, it will occasion the clock to lose or gain a minute in every twenty-four hours — 
 a minute being the l-1440th part of a day. The alteration in length required to produce a difference 
 of a second a day will therefore be almost inconceivably small, and such as a trifling variation in the 
 temperature of the air would be sufficient to produce. The amount will vary with the material em- 
 ployed. If the pendulum-rod be of dry varnished deal, an alteration of the temperature to the amount 
 of 10° (Fahr.) will only affect its going by one second a day. But if iron wire be employed, the al- 
 teration is three times as great ; and it is increased to five seconds by employing brass. Hence, to in- 
 sure the accurate going of a clock, some means must be devised to compensate for this source of error. 
 
 This compensation is sometimes effected in clocks by the appa- 
 ratus termed the mercurial pendulum, the form of which is shown 
 in the annexed drawing, Fig. 3752. The rod of the pendulum con- 
 sists of a flat piece of steel, which is formed at the bottom into a kind 
 of stirrup, to carry a glass jar securely fixed to it. This jar is partly 
 filled with mercury, which serves as the weight or bob of the pendu- 
 lum. When a change of temperature causes the steel rod to expand 
 downwards from its point of suspension, it also occasions an expan- 
 sion of the mercury upwards from the bottom of the jar ; and as the 
 expansion of any given bulk of mercury is many times greater than 
 that of the same bulk of steel, the rise of the mercury in the jar 
 counteracts the lowering of the whole jar by the expansion of the 
 rod ; so that the place of the centre of oscillation remains the same, 
 and the rate of vibration continues unaffected. The quantity of mer- 
 cury requisite for the purpose can only be accurately determined by 
 experiment ; but in general it will be found that the height of the 
 column should be about 6'7 inches. If the column is not high enough, 
 its expansion will not counteract that of the steel rod; if it be too 
 high, the pendulum will be over-compensated, so that heat will cause 
 it to gain, and cold to lose, — contrary to the usual rule. Of course 
 what has been said of the mode in which the two expansions balance 
 each other, equally applies to the contractions which will take place, 
 in the steel rod and in the mercury, from the operation of cold. The 
 absolute length of the pendulum is adjusted by a screw at D, by 
 turning which the stirrup is raised or lowered upon the rod. At C is a projecting index, which points 
 to a circular scale below, by which the pendulum’s arc of vibration may be observed from time to 
 time. 
 
 A very simple compensation pendulum, which may be applied to any clock at the most trifling ex- 
 pense, consists of a wooden rod, dried and varnished ; carrying at its lower end, by way of bob, a hollow 
 leaden cylinder, which rests on a serew at the bottom of the rod. If the rod be made about 46 inches 
 long, and the lead cylinder about 14 inches long, it will nearly vibrate in seconds, (since the centre of 
 oscillation will be at about the middle of the leaden cylinder, and therefore at about 7 inches from the 
 end of the rod ;) and the expansion of the lead upwards is sufficient, or nearly so, to counteract that of 
 the rod downwards. There is another very ingenious compensation pendulum, which was invented by 
 Harrison, to whom we are so much indebted for his improvements in chronometers. This is termed, 
 from its form and aspect, the gridiron pendulum. (See Pendulum.) Many other contrivances have 
 been devised for the same purpose ; but they are not superior to these. 
 
 The regular going of a clock will partly depend also upon the steadiness with which it is fixed ; and, 
 it is therefore desirable that a clock for scientific purposes should be as firmly supported as possible. 
 After all, however, there is one source of error for which it does not seem easy to devise a remedy; — 
 this is the varying density of the air, which wall produce a variation in the resistance to the motion of 
 the pendulum. When the air is dense, as shown by a rise of the mercury in the barometer, the resist- 
 ance is increased, and the clock will go slower ; the contrary result occurs when the pressure of the 
 air is diminished, as shown by a fall of the mercury. An attempt has been made to correct this error, 
 by attaching small barometers to the sides of the pendulum ; it being intended that the rise of the mer- 
 cury in the tube, by slightly raising the centre of oscillation, should counterbalance the effect of the 
 increased resistance. This ingenious idea has not yet been properly applied to practice. To show the 
 perfection at which clockmaking has arrived, it may be mentioned that several clocks are now going, 
 whose errors are less than l-10th of a second daily. 
 
 Watch escapements. — As in the clock it is desirable to remove the pendulum as much as possible 
 from the constant influence of the moving power, so is it desirable in the watch to withdraw the balance 
 from the same influence, slight variations of which (such as must be continually occurring from various 
 causes) must otherwise greatly affect its regularity. In order to effect this, various kiuds of escape- 
 ments have been devised. 
 
 The vertical escapement is the oldest escapement of all, which, after having first been adopted in 
 flocks, was applied in the construction of watches. Its nature is explained by Fig. 3754, (a contrate- 
 whcel, b escape or wheel, c the verge, d the balance.) That which is here called the balance-wheel 
 was, when originally applied in a horizontal position to the primitive clocks, termed the croVn-wheel 
 
WATCHMAKING. 
 
 829 
 
 evidently from its resemblance to a crown : this same wheel, when employed in the watch, (supposing 
 the latter to be placed on its face or back,) obviously revolves vertically to the plane of the horizon ; 
 hence, watches made with this escapement are termed vertical. Watches are still manufactured on 
 this principle, which has its conveniences, as it is understood in every part of the world where a man 
 pretends to repair watches, and is the cheapest of ail movements, and perhaps for this reason will 
 never be wholly superseded. 
 
 In this escapement, as in the common recoil escapement of clocks, the teeth of the balance-wheel are 
 continually pressing -on the pallets, in such a manner as to be exercising a constant influence over the 
 vibrations of the balance ; and a fresh impulse is communicated at each vibration. In all the improved 
 escapements, the balance is so detached from the train of wheels, that it only receives a momentary 
 impulse from the moving power ; and in the intervals, the whole train of wheels is checked. In general 
 this impulse is communicated only at every second vibration of the balance ; that is, the balance, after 
 receiving one impulse, completes its vibration in that direction and returns to the same point again, 
 before it receives the next. 
 
 3754. 3755. 
 
 3756. 
 
 One of the contrivances by which these objects are fulfilled, is that known as the duplex escape- 
 nent, so named from the escapement-wheel having two sets of teeth on its rim ; the action of which 
 will be easily comprehended by reference to Figs. 3755 and 3750. A A represents the scape-wheel, 
 which is provided with two sets of teeth ; — 1, 2, 3, Ac., projecting from its sides, and termed the 
 teeth of repose ; — and ahe, Ac., rising from the surface of the wheel, and termed the teeth of impulse. 
 On the axle of the balance there is fixed a piece 0 D, termed the impulse-pallet; this stands just above 
 the surface of the scape-wheel, so that the teeth a b c must strike the projecting portion D, when the 
 wheel revolves. On the same axis, but placed a little below it, so as to be on the level of the teeth 1, 
 2, 3, Ac., is a small roller made of ruby; this has a notch cut out of one side of it, as seen. in.Fig. 3755. 
 The scape-wheel is constantly being urged, by its connection with the going-train, in the direction from 
 3 to 1 ; and consequently, in the position represented in Fig. 3755, the tooth a is just about to strike 
 the impulse-pallet D. The impulse being given, the balance moves round, and the tooth a escapes 
 from the pallet. The next tooth h does not immediately fall against it, however ; since, before it can 
 do so, the tooth 1 has been stopped . against the ruby roller. There it is held, during the vibration of 
 the balance and its return, until the roller comes back into the position shown in Fig. 3755, which will 
 permit the point of the tooth 1 to pass by the notch ; so that the tooth b may fall on the pallet D, and 
 give the balance a renewed impulse just as its next vibration is commencing. Thus it is seen that the 
 teeth abc are those which give the impulses to the pallet ; whilst by means of the check which, in the 
 intervals, the points of the teeth 1, 2, 3 receive against the ruby roller, the train is kept in repose. 
 
 Fig. 3756 is a perspective view of this escapement, the cogs a being placed upright nearer the 
 centre, while the long teeth b are in the plane of the wheel ; hence arises a double action : c is the 
 balance. This escapement is of English invention : watches having it are perhaps to be ranked next 
 to the chronometer in value, particularly as regards the length of time which they will continue to per- 
 form without cleaning, or requiring a fresh application of oil. 
 
 To this movement there are, it must be acknowledged, some objections. It is of very delicate con- 
 struction, and if not made and put together by a workman of superior talent, the watch is liable to 
 stop in the pocket. 
 
 This escapement is not so commonly employed, however, as the one known under the name of the 
 detached lever. This essentially consists of the dead-beat escapement, applied to the balance in such a 
 manner, that a straight piece prolonged from the anchor or crutch, on the other side of its centre of 
 motion, shall give a momentary impulse to a ruby roller fixed on the axle of the balance, each time 
 that either of the pallets escapes. 
 
 Neither of these, however, is equal in perfection to that known, after the name of its inventor, as 
 Earnshaw’s detached escapement. This is the one at present universally employed for chronometers 
 and the most accurate time-keepers ; and nothing but the delicacy of its construction, and its consequent 
 expensiveness, prevents it from coming into general use. Its action will now be explained by the help 
 of Fig. 3757. A A represents the scape-wheel, the teeth of which, 1, 2, 3, 4, Ac., are 
 considerably undercut on the side or face towards which they move. At B B is shown 
 the steel roller or main-pallet, which is fixed on the axle of the balance. This has a 
 large notch cut in it; and the side of this notch nearest the tooth 1 is guarded by a thin 
 plate of ruby, on which the points of the teeth strike as they pass it. The same arbor 
 carries the small lifting-pallet q , which has a projection on one side, that lifts the end 
 E p of the locking-lever or detent next to be described. This lever EE has its centre 
 of motion at c, where it is attached by a screw to a stud S, which is firmly fixed to one 
 of the plates of the chronometer. Near this stud, the lever is made thin and elastic ; 
 so that it has a springing power which keeps it pressing towards the scape-wheel, un- 
 less removed from that position. It is prevented from pressing too far, however, by the screw d, which. 
 >.« fixed into the stud D ; for the head of this screw acts as a stop to the lever, and prevents it from 
 
S30 
 
 WATCHMAKING. 
 
 moving further towards the right than the place in which it is seen. At the other end of the lever is 
 an extremely delicate springy), which extends a little beyond the extremity of the detent. In the mid- 
 dle of the lever is the pin o, which serves to stop the teeth of the scape-wheel, when the detent is in 
 the position represented in Fig. 3757, which is that of repose. 
 
 The following is the mode in which these parts act upon one another. The tooth 5 of the scape- 
 wheel is seen to be resting against the pin o ; whilst the tooth 1 is nearly ready to advance and strike 
 the ruby face of the main-pallet BBB, but is prevented from doing so by this locking of the wheel. 
 The balance, however, being in motion from right to left, (by the elasticity of its spring,) carries round 
 with it the lifting-pallet q , the projection on which acts against the end of the lifting-spring ; and this 
 spring, pressing against the end of the detent E E, raises it a little from its place, towards D, so as to 
 withdraw the pin o from the point of the tooth 5. The wheel being thus unlocked, the tooth 1 strikes 
 against the ruby face of the main-pallet, and gives the balance an impulse, which increases the extent 
 of its vibration. Before the tooth has entirely escaped, however, from the ruby face, the lifting-pallet q 
 lias completely passed the point of the lifting-spring p ; so that the detent is at liberty to fall back into 
 its place, which it is caused to do by the spring at its fixed end. Hence, by the time that the tooth 1 
 has escaped from the main-pallet, the pin o will be in a position to check the next tooth 6, which ad- 
 vances against it ; and the whole train of wheels, therefore, again comes to repose. The balance, hav- 
 ing completed its vibration forwards, begins to return, by the elasticity of its spiral spring. In this 
 return, the lifting-pallet q has again to pass the end of the lifting-spring p ; but it now merely separates 
 this from the end of the detent, and does not move the detent itself. The locking of the scape-wheel 
 still continues, therefore, until the balance has completed its return vibration, and again begins to move 
 forwards; the lifting-pallet will then again raise the detent and set free the scape-wheel; the balance 
 will receive a fresh impulse from the action of the teeth upon the ruby face of the main-pallet ; and 
 the detent will again lock the wheel, as soon as the tooth has escaped. All this complex action, which 
 occupies so long in the description, is really repeated in every half-second, — that being the time in 
 which the balance is usually made to perform its double vibration. 
 
 Compensation balance. — It is essential to the accurate going of a chronometer, that it should be fur- 
 nished with some means of compensating the action of heat or cold upon the balance-spring, analogous 
 to those by which compensation is made for the effect of change of temperature upon the pendulum. 
 This is here also effected, by taking advantage of the unequal expansion of different metals ; so that 
 the change produced in the length of the spring may be antagonized by a change in the form of the 
 balance, producing a variation in the amount of force necessary to move it. From what has been 
 formerly stated of the principles of the lever, and wheel, and axle, it is evident that, the nearer the 
 chief weight of the balance is disposed to the centre of motion, the less amount of force will be required 
 to turn it. Consequently if — when the action of heat upon the balance-spring has weakened it, by in- 
 creasing its length — the same action can be made to cause the weight which the spring has to move 
 to approach nearer the centre, a perfect compensation may be effected. In the same manner, the spring 
 being shortened by cold, and thereby rendered more powerful, the weight ought to be carried further 
 from the centre, so as to require a greater moving power. 
 
 These objects are accomplished by the compensation balances represented in Figs. 3758 and 3759. 
 The principle of both is the same ; and the only difference consists in this, that the necessary weight is 
 given in Fig. 3759 by a single piece W on each arm of the balance ; whilst in Fig. 3758 it is distributed 
 among the four screws 1, 2, 3, 4, which are inserted into each arm. These balances are not made in the 
 
 3758. 
 
 3759. 
 
 37C0. 
 
 form of a complete wheel ; but are composed of the cross-bar A B attached to the axis, and of the two 
 circular arms carried by its ends. Each of these circular arms is a compound bar of brass and steel, 
 the brass being on the outside. As brass expands by heat much more than steel, the effect of a rise of 
 temperature is to cause the curvature of the bars to increase, so that their ends a a curl in, as it were, 
 towards the cross-piece A B, carrying inwards the weights W W, Fig. 3759, or the screws 1, 2, 3, 4, Fig. 
 3758 ; hence the balance will be more easily made to revolve, and the weakened action of the spring 
 will be compensated. On the other hand, the effect of cold will be to make the brass contract more 
 than the steel, and thus to diminish the curve of the circular bars, rendering them straighter, so as to 
 increase the distance of the weights from the centre, and thereby to increase the power requisite to 
 move them ; thus counterbalancing the increased power given to the spring by its own contraction. 
 
 There is much difficulty in exactly adjusting this compensation to the error it is desired to correct. 
 It may be that it is too great ; in which case the chronometer will gain by heat and lose by cold. This 
 is corrected by shifting the weights ~W W, Fig. 3759, towards a part of the circular bars nearer to their 
 attachment, so that they may be less influenced by the alteration of the curvature of the bars ; and the 
 same result is obtained in the other form of the balance, Fig. 3758, by drawing out the screws 4,4, and 
 
WATCHMAKING. 
 
 831 
 
 screwing in 1 , 1 . On the other hand, if the compensation be not sufficient, the weights must be shifted 
 towards the ends a a oi the circular bars, so as to be more altered in place, when the curvature of the 
 bars is changed by an alteration of temperature. The screws C 0 are obviously not affected by these 
 changes of curvature, since (liey pass into the ends of the straight bar A B ; but the effect of screwing 
 them in or drawing them out, is to alter the rate at which the balance will vibrate ; for if the moving 
 power remain the same, and a portion of the weight be carried to a greater distance from the centre — 
 as it is by partly drawing out the screws C C — the vibrations will be rendered slower ; and the contrary 
 effect will be produced by screwing them in. Now in finally adjusting a chronometer, it is found unde- 
 sirable to alter the length of the balance-spring, after the point has once been ascertained at which its 
 vibrations are isochronous, or nearly so. Hence, in order to bring it to the proper rate, it is found ad- 
 vantageous to make it go faster or slower as required by slightly altering these screws, which are hence 
 called, to distinguish them from the others, mean-time screws. 
 
 The chronometer . — Fig. 3760 shows the balance-wheel of a chronometer; a is the balance-spring, the 
 elastic force of which, when wound up by the motive power, acting through the escapement, into a state 
 of tension, gives motion to the balance h. The elastic force of this balance-spring varies by change of 
 temperature, producing an error of six minutes in twenty-four hours in the time indicated by the chro- 
 nometer, for 68° of Fahrenheit. This irregularity is corrected by the balance b varying its diameter, 
 much in the same manner as the balls of a steam-engine govern that machine ; with this exception, that 
 while the balls of a steam-engine act by gravity and centrifugal force, the effect is here mechanically 
 produced from the different metals (brass and steel) expanding and contracting differently under a 
 change of temperature, thus varying the diameter, and consequently the inertia of the balance in ac- 
 cordance therewith. It must be recollected that no chronometer can keep a uniform rate unless the 
 tension of the balance-spring has an invariable ratio to the inertia. 
 
 Heat renders the balance-spring a weaker, while the inertia of the compensation balance b is de- 
 creased, thus compensating the loss occasioned by the relaxation of the spring. 
 
 The compensation balance, by which the error is compensated, may be thus explained : The compen- 
 sation, as already observed, is produced by the variation in the diameter of the circle b. The internal 
 part of the rim c is of steel, while the external part d is of brass ; these are united by heat, causing a 
 partial fusion of the brass, and consequent union with the steel. The degree of expansion of these 
 metals upon application of the same degree of heat varies ; the brass expands more than the steel, and 
 as it cannot release itself from this, so neither has it the power of expanding itself in length, being re- 
 strained by the steel : consequently an increase of curvature is produced by the brass forcing the steel 
 to change its original circular form, the inertia or power of the compensation balance hence varies, and 
 compensates for the loss or gain in the balance-spring occasioned by a change of temperature. The rim 
 of the balance is cut open at e, to admit of this variation in its 
 form; the screws/ can be inserted in any of the holes g, and 
 according to their position in one or the other, these screws are 
 moved more or less in towards the centre by the increase of 
 curvature of the rim before mentioned, thus contributing to vary 
 the inertia of the balance in a small degree, but admitting of 
 original adjustment for this purpose — giving that finish to the 
 principle of this contrivance on which the exquisite accuracy of 
 the chronometer in great measure depends. This principle of 
 compensation is the same in all watches to which a compensa- 
 tion balance is applied, viz., to those of the duplex and lever 
 kind. The escapement used in the chronometer, as seen in Fig. 
 
 3761, is termed a “ detached” one, which means, that the vibrations performed by the balance arc nearly 
 detached from the pressure of the motive power during the greater part of its arc of vibration ; one 
 great advantage is, that it requires no oil. This escapement is of French invention, but improved by 
 English artists. 
 
 These are the principles on which the excellence of a time-keeper depends. In their application to 
 practice, however, every thing depends on the perfection with which the machine is constructed ; and 
 the minuteness of the conditions required for the good going of a chronometer may be judged of from 
 the fact with which practical men are familiar — that, of two chronometers, constructed upon the same 
 plan, and finished with equal care in all respects by the same hand, one may go very well, and the 
 other comparatively badly, without any discoverable difference between them. In finally adjusting a 
 chronometer no attempt is made to keep it exactly to mean time ; that is, to make it continue to point, 
 day after day, and week after week, exactly to the correct hour; for it is just as advantageous to allow 
 it to gain or to lose a few seconds a day, provided that the gain or loss be regular in its amount; since 
 the real time may be known with equal accuracy from that which the chronometer indicates. Thus, 
 suppose that we have a chronometer which was set 36 days ago, since which time it has been gaining 
 5 seconds a day ; if its gain have been regular, its whole gain during that period will be (5 X 36) 180 
 seconds, or three minutes ; and three minutes being deducted from the time to which the hands point, 
 we shall have the real time. This regular amount of gain or loss is called the rate of a chronometer ; 
 and it is thus expressed : When the chronometer is said to have a rate of 2'53, we understand that 
 it is gaining 2-} seconds per day ; but if its rate is — 3'2, we know that it is losing 31- seconds per day. 
 The more closely it keeps to this rate the better the instrument will obviously be ; but if it vary much 
 from its rate, even though its errors should be sometimes on one side, and sometimes on the other, so as 
 to compensate one another, and make the general average the same, the performance is bad, and can- 
 not be relied on. 
 
 When the minuteness of the parts of a chronometer is considered, and the variety of disturbances to 
 which it is exposed, the accurate performance to which it may be brought is most wonderful. For it 
 must be remembered how very trifling a cause, if constantly aedng, (such as a slight thickening of the 
 
832 
 
 WATCHMAKING. 
 
 oil,) will greatly alter the result. Thus, as there are 1440 minutes in a day, any cause which makes 
 each vibration of the balance (of which there are five in a common watch) take place in l-7200th part 
 less or more than its usual time, will cause the time-keeper to gain or lose a minute a day. And as 
 there are 86,400 seconds a day, any cause which makes each vibration of the balance of a chronometer 
 (which usually occurs 4 times in a second) take place in 1-432, 000th part less or more than its usual 
 time, will cause it to gain or lose a second a day — an error of very considerable magnitude. When it 
 was first supposed that chronometers could be made sufficiently perfect to give important assistance in 
 the determination of the longitude at sea, (the mode of doing which will be explained hereafter,) a par- 
 liamentary reward of £10,000 was offered in 1714 to any one who should construct a time-keeper capa- 
 ble of doing so within the limit of sixty geographical miles; £15,000 if to forty miles; and £20,000 if 
 to thirty miles. Now a chronometer that has so much changed its rate a9 to have gained or lost, in a 
 few weeks, two minutes more than it was estimated to have done, would gain the highest of these re- 
 wards; so that the utmost degree of accuracy which was contemplated as possible, at the beginning of 
 the last century, when this act was passed, is far surpassed at present. 
 
 The reward was gained by John Harrison, who, in 1736, completed the first chronometer used at sea, 
 after many years of patient study and laborious experiment. He gradually improved his machine ; 
 and in 1761 the first trial was made of it, according to the regulations of the act of Parliament, by a 
 voyage to Jamaica. In consideration of his advancing years his son was allowed to take this voyage 
 instead of himself. After eighteen days’ navigation the vessel was supposed by the captain to be 13° 
 50' west of Portsmouth; but the watch giving 15° 19', or a degree and a half more, was condemned 
 as useless. Harrison maintained, however, that if Portland Island were correctly marked on the chart, 
 it would be seen on the following day ; and in this he persisted so strongly, that the captain was in- 
 duced to continue in the same course, and accordingly the island was discovered the next day at seven 
 o’clock. This raised Harrison and his watch in the estimation of the crew ; and their confidence was 
 increased by his correctly predicting the several islands as they were passed in the voyage to Jamaica. 
 When he arrived at Port Royal, after a voyage of 81 days, the chronometer was found to be about 5 
 seconds too slow ; and finally, on his return to Portsmouth, after a voyage of five months, it had kept 
 time within about one minute and five seconds, which gives an error of about 18 miles. This amount 
 was much within the limits prescribed by the act ; but Harrison did not receive the whole reward until 
 a second voyage had been made ; and large as the sum appears, it cannot be regarded as more than 
 equivalent to the devotion of extraordinary talents, with unwearied perseverance, during 40 years, to 
 the attainment of an object whose importance can scarcely be estimated too highly. 
 
 As an illustration of the improvements which have been since made in the construction of chronome- 
 ters, the following circumstance, mentioned by Dr. Arnott as having occurred to himself, is of great in- 
 terest. “ After several months spent at sea,” he says, “ in a long passage from South America to Asia, 
 my pocket chronometer and others on board announced one morning that a certain point of land was 
 then bearing north from the ship at a distance of fifty miles ; in an hour afterwards, when a mist had 
 cleared away, the looker-out on the mast gave the joyous call of ‘ Land ahead !’ verifying the report of 
 the chronometers almost to one mile, after a voyage of thousands. It is allowable at such a moment, 
 with the dangers and uncertainties of ancient navigation before the mind, to exult in contemplating 
 what man has now achieved. Had the rate of the wonderful little instrument, in all that time, been 
 quickened or slackened ever so slightly, its announcement would have been useless, or even worse ; but 
 in the night and in the day, in storm and in calm, in heat and in cold, its steady beat went on, keeping 
 exact account of the rolling of the earth and of the stars ; and in the midst of the trackless waves which 
 retain no mark, it was always ready to tell its magic tale, indicating the very spot of the globe over 
 which it had arrived.” 
 
 It is surprising that, in spite of the great advantages resulting from the use of chronometers in navi- 
 gation, many ships are sent to sea without them, even for long voyages. Not unfrequently must it occur 
 that the knowledge of the exact position of the ship, which may be obtained by the chronometer, pro- 
 duces a great saving of time, as well as contributes to the avoidance of danger. A remarkable instance 
 of this was mentioned to the author, a few years since, as having just then occurred. Two ships were 
 returning to London about the same time, after long voyages, one of them provided with chronome- 
 ters, the latter destitute of them. The weather was hazy, and the winds baffling; so that no ship, whose 
 position was uncertain, could be safely carried up the British Channel. Confident in his position, how- 
 ever, the captain of the first ship stood boldly onwards, and arrived safely in the Thames, whilst the 
 other ship was still beating about in uncertainty near the entrance to the Channel. The first ship dis- 
 charged her cargo, took in another, set sail on a fresh voyage, and actually, in running down the Chan- 
 nel, encountered the second ship still toilsomely making her way to her port ! 
 
 Of the degree of accuracy which chronometers are capable of exhibiting, some idea may be formed 
 from the following statement, kindly communicated to the author by a gentleman practically conversant 
 with them. A chronometer made by Molyneux had its daily rate determined, in August, 1839, to be a 
 loss of 7 seconds per day. It was then placed in a ship which traded to the coast of Africa, and was 
 consequently exposed to great variations of temperature. Yet when again placed under careful obser- 
 vation in November, 1840, (sixteen months afterwards,) its daily loss had only changed to 6'7 seconds, 
 being a difference of only 3-10tbs of a second a day. As opportunities for ascertaining the real position 
 of the ship, without chronometers, frequently occur at sea, any error in these may almost always be 
 detected before it has accumulated to any great extent ; but even supposing that no such opportunity 
 had occurred for six months, and that the alteration of the rate had taken place at once, and had been 
 entirely unknown, the whole error would have been under a minute of time, and consequently less than 
 15 miles of space. Another chronometer, constructed by Muston, which had made the same voyage, 
 and been out about the same length of time, had its previous gaining rate of 1’9 seconds a day increased 
 to 2'3 seconds; the difference being here 4-10ths of a second. It is customary for two or more chro- 
 nometers to be carried by the same ship, that they may check one another ; for if one alone were 
 
WATCHMAKING. 
 
 833 
 
 3762. 
 
 trusted to, an accidental irregularity in its going might lead to great error. The average of several — • 
 their errors counterbalancing each other — will be most likely to give the real time with great exactness. 
 
 Striking apparatus . — The apparatus for striking the hour is somewhat complex ; but we shall 
 endeavor to make its action intelligible, as it is a very beautiful specimen of ingenious mechanism. 
 The form which will be described is that which is adopted in the best English clocks : a simpler plan is 
 adopted in the cheap German clocks, which are now so largely employed in this country ; but they are 
 very liable to get out of order. The difference consists, however, only in the apparatus by which the 
 striking is regulated, as to time and number of strokes ; the mechanism by which the hammer is made 
 to strike the bell is the same in both cases. It consists of a train of wheels and pinions, put into action 
 by the spring contained in the barrel E, Fig. 8749, which turns the fusee F. The fusee carries round 
 with it the main-wheel e, which has 81 teeth ; this drives the pinion p of 8 leaves, which carries on its 
 axle the pin-wheel f, having 64 teeth. In the rim of this pin-wheel are 8 pins, which lift the hammer 
 s by acting on its tail t when the train is in motion. The hammer being gradually lifted by each pin. 
 is at last let go by it, and is made to strike the bell by the spring u. The pin-wheel drives a pinion q 
 of 8 leaves, which carries round the pallet-wheel g of 56 teeth : as the pin-wheel has 64 teeth, it turns 
 the pallet-wheel pinion 8 times for each revolution of its own, consequently this pinion makes one revo- 
 lution for every stroke of the hammer, an arrangement of which the use will be presently shown. 
 The pallet-wheel acts on a pinion z of 7 leaves, on which is the warning-wheel h of 48 or 50 teeth, and 
 this last turns the fly-pinion i. The object of this part of the train is only to equalize the motion, 
 which is principally effected by the constant resistance of the air against the surface of the plate (termed 
 the fly) which is whirled very rapidly round by the highest pinion. If it were not for this addition, the 
 pin-wheel would move onwards with a jerk, after each* pin had escaped from the tail of the hammer. 
 
 The striking-train remains completely at rest during each hour’s movement of the going-train, and 
 is only allowed to act at the conclusion of one hour and the commencement of the next. The mode 
 in which it is restrained in the intervals, and its action at the proper time permitted and regulated, 
 will now be explained. The mechanism by which this is effected is shown in Fig. 3162. It is situated 
 immediately behind the dial. The axis of the centre-wheel, as 
 already mentioned, is prolonged through the dial, to bear the 
 minute-hand. In the striking clock this also bears a small wheel 
 a, which gives motion to another wheel b of the same size and 
 number of teeth ; hence this wheel, like the former, revolves once 
 in each hour. On the centre of this wheel is a pinion of 6 or 8 
 leaves, which turns a wheel c with a hollow axle, moving on the 
 same centre as a, but at a different rate, as in the watch. This 
 wheel has 12 times the number of teeth that the pinion contains, 
 and therefore moves at only 1-1 2th of the rate. To it the hour- 
 hand is affixed ; and it also carries a peculiarly shaped piece of 
 metal d, which is called the snail. The edge of this snail is cut 
 into 12 steps, each of which is a twelfth of the circle of which it 
 forms a part ; but the distance of each from the centre increases regularly from 1 to 1 2. 
 a circular rack, fixed to the end of a bent lever ef g h, whose centre of motion is at/i By the action of 
 the bent spring i this rack will be made to fall towards the left, when permitted to do so ; but the 
 amount to which it shall fall is governed by the position of the snail, against the edge of which the pin 
 h will be brought to bear. This spring is prevented from forcing the rack out of the position shown in 
 the figure, by means of the projecting piece on the lever k, which turns on the centre /, and drops by 
 its own weight into the teeth of the rack. The form of these teeth is such, that when the rack is moved 
 from left to right, the catch is lifted by them and allows them to pass ; but, so long as it is allowed to 
 drop between the teeth, it completely prevents the motion of the rack from right to left. The lever k, 
 with its catch, may be lifted by the bent lever m p n, whose centre of motion is at p ; and this is acted 
 on by a pin in the circumference of the wheel b, which is seen in the figure, close against the tail of 
 the lever. 
 
 Only one other part remains to be described — that which is known as the gathering-pallet. The axle 
 of the pallet- wheel g, Fig. 3749, projects through the front plate; and is furnished with a projection, 
 seen at o, resembling one leaf of a pinion. This works into the teeth of the rack in such a manner that, 
 as the axle turns round, the rack is gathered up by it, to the amount of one tooth for each revolution. 
 When the machinery is in the position shown in the figure — which it has during the whole time that the 
 striking-train .is at rest — a projection on the gathering-pallet rests on a pin which projects from the rack, 
 as seen at r. It is this which keeps the striking-train from acting ; for, so long as this projection from 
 the axle of the pallet-wheel bears upon the pin, so long must the pallet- wheel, and consequently the 
 whole remainder of the striking-train, be prevented from running on. 
 
 But when the time of striking is nearly come, the pin on the wheel b acts on the tail of the lever 
 npm; the end q of which raises the lever k l, and consequently lifts its catch out of the rack o, which 
 is thus set free. The spring i, therefore, pressing upon the projection below f, causes the rack to fall 
 towards the left; and therefore sets free the projection on the gathering-pallet, by withdrawing the pin 
 on which it rested. Hence the whole striking-train would be set in action by its weight ; if it were not 
 that, at the same time that the gathering-pallet is freed, another check is provided. The end q of the 
 bent lever mpn bears a projecting piece, which, when the lever is raised, stops a pin placed on the cir- 
 cumference of the warning-wheel h, Fig. 3749. So long as the lever remains in this position, therefore, 
 the striking-train is prevented from acting. The amount of motion given to the rack is determined by 
 the place of the snail. In the position represented in the figure, the pin h would be stopped by the 
 second step ; and thus the rack would only be permitted to move to the amount of two of its teeth. 
 If the position of the hour-wheel were such, that the twelfth step of the snail corresponded with the 
 end h of the rack -lever, then the pin would not be stopped so soon ; and the rack would fall towards 
 Vol. n. — 53 
 
 At e is seen 
 
834 
 
 WATCHMAKING. 
 
 the left to the amount of twelve teeth. This preparatory action is usually made to take place about 3 
 or 5 minutes before the expiration of the hour, and it is called (jiving warning. 
 
 The machinery remains in this position until the minute-hand points to XII., at which time the wheel 
 h has so far advanced that its pin escapes from under the end of the lever, and thus allows it to fall, so 
 that the end q no longer checks the pin on the warning-wheel. The striking-train is now set entirely 
 free ; the weight or spring that moves it produces a rapid revolution of its wheels ; and the pins on the 
 pin-wheel, acting on the tail of the hammer-lever, cause the successive strokes on the bell. This move- 
 ment goes on until it is checked by the action of the gathering-pallet on the rack. It has been alreadv 
 mentioned that the pallet-wheel, from the axle of which the gathering-pallet projects, turns round once 
 for every stroke given to the hammer; and in each turn it gathers up one tooth of the rack, causing it 
 to move towards the right, so as to regain jis original position. The projecting catch of the lever kl 
 drops between the teeth at each advance, and prevents the rack from being moved back by the spring i. 
 This goes on until the rack has been completely brought back to its first position, and then the projec- 
 tion on the gathering-pallet will be again checked by the pin r, and the striking-train would be 
 brought to rest. 
 
 It is evident, then, that the number of strokes will be determined by the number of revolutions 
 which the gathering-pallet is allowed to make ; this depends upon the number of teeth on the rack 
 which have to be gathered up by it ; and this number is regulated by the extent to which the rack is 
 permitted to fall, by the bearing of the pin h against the edge of the snail. It is almost impossible for 
 any error to be committed by a movement so constructed ; but the striking-train of the common Ger- 
 man clocks, now so largely imported into Britain, is regulated by an apparatus of simpler construction, 
 which is very liable to give wrong indications. . It principally consists of a large wheel, (termed the 
 count-wheel,) usually placed at the back of the clock, on which are cut 18 teeth ; this is so connected 
 with the striking-train, that it moves on one tooth for each stroke. The number 78 is the sum of all the 
 strokes which the clock should make in 12 hours ; consequently, after all these strokes have been made, 
 the wheel returns to the same place again. From the surface of the wheel, near its edge, there projects 
 a rim, in which are cut a series of notches, at intervals corresponding with the number of strokes. Thus, 
 between the first and second notches there is an interval amounting only to one tooth of the wheel ; 
 between the second and third notches an interval of two teeth ; and so on up to the twelfth notch, the 
 interval between which and the first is 12 teeth. The use of these notches is to receive a catch or pro- 
 jection, which keeps the striking-train at rest during the hour, and regulates the number of strokes. 
 When the clock gives warning, this catch is lifted out of the notch; but there is a temporary check 
 applied to the warning-wheel as in the last case. When this check is removed, the train immediately 
 begins to move, and continues in action until it is stopped by the falling of the catch into the succeed- 
 ing notch. The number of strokes is determined, therefore, by the number of teeth which the count- 
 wheel shall have moved on before the catch falls into this notch — or, in other words, by the number of 
 teeth between each notch and the succeeding one. 
 
 The advantage of this last plan consists in its simplicity, and the facility with which the apparatus 
 may be constructed. Its disadvantage consists in the readiness with which it may be put out of order. 
 For it will be easily seen that if, from any cause, the clock be made to strike at an improper time, the 
 count-wheel advances, and the number of strokes made will be one more than the last ; so that, when 
 it should next strike the hour, the number of strokes is one too many. Or if any cause (such as neglect- 
 ing to wind up the weight of the striking-train) should prevent the clock from striking at the proper 
 time, the count-wheel remains stationary ; and when the clock next strikes, it gives the number succeed- 
 ing the one which it last struck, which may, of course, be altogether wrong. On the other hand, in the 
 more perfectly constructed clock, the striking may be repeated any number of times within the hour, or 
 it may be made to cease for a time altogether ; and yet, when the clock next strikes the hour, it shall 
 do it correctly. For the number of strokes, as just explained, is dependent upon the position of the 
 snail, which is carried round by the hour-wheel whether the clock strikes or not ; and which must, there- 
 fore, always correspond with the place of the hour-hand. In some clocks of this construction, there is 
 a simple contrivance for causing the hour to be struck at any time. This consists of a lever x, to one 
 end of which the string t is attached, whilst the other carries a pin that raises the lever rn. The action 
 of this lever is checked by the two pins s and z, which prevents it from being moved too far in either 
 direction. When the string t is pulled the lever m is lifted, and all those changes take place which 
 have been described as occurring in the ordinary warning of the clock. When the string is let go, the 
 lever is made to return to its place by the spriug y ; the lever m falls, the warning-wheel is released, 
 and the proper number of strokes is made. Such a contrivance is convenient to those who desire to 
 know the hour during the night. 
 
 Where a clock is made to strike the quarters as well as the hours, a third train of wheels is required. 
 The mechanism is the same in principle with that which regulates the striking of the hours. The axle 
 of the minute-hand carries round a snail cut into four steps ; and on a wheel corresponding to b, and 
 revolving therefore in an hour, there are four pins, one of which lifts the lever that sets free the rack 
 every quarter of an hour. The rack has four teeth, corresponding with the four steps of the snail ; and 
 the passage of each tooth permits one stroke on the quarter-bell. Most frequently the quarter-stroke is 
 made upon two bells ; and this is accomplished simply by having a set of pins on each side of the pin- 
 wheel, of which one set acts on one lever, and the other set (acting a little afterwards, so that the two 
 strokes may not be made at the same moment) on the other lever. In clocks constructed for purposes 
 in which great accuracy is required, it is necessary to dispense altogether with the striking apparatus ; 
 since a certain degree of force is required to set it in action, that would derange the very regular move- 
 ment of a delicate and perfect clock, in which the power of the weight ought to be no more than is 
 requisite to keep the pendulum in action. 
 
 The same apparatus has been applied to watches ; but when made on so small a scale and carried about 
 in the racket, its action is extremely liable to become deranged, and it is therefore of little use. The 
 
WATCHMAKING. 
 
 835 
 
 ordinary repeating-watches are made, not to strike the hours regularly, but merely to indicate them 
 when desired to do so. In order to effect this, it is not requisite that the watch should be furnished 
 with a second barrel and fusee with a distinct striking-train of wheels, for it is easy to apply a power 
 sufficient to produce the strokes every time that the watch is applied to. for this information. This is 
 usually accomplished by pushing in the pendant, or projecting portion to which the chain is attached ; 
 and by this a spring is compressed, which sets in action the mechanism that produces the strokes. The 
 number of strokes is regulated by a snail, resembling that employed in clocks. The ordinary repeating- 
 watches are still very complex in their construction ; and we prefer describing one invented some years 
 ago by Mr. Elliott, of Clerkenwell, in which the number of parts is greatly reduced by the combination 
 of several into one. The striking portion of this watch is represented in Figs. 3763 and 3764. The 
 most important part of it is a flat ring or centreless wheel, of nearly the same diameter with the watch, 
 supported in its place so as to admit of a circular motion, by four grooved pulleys round its external 
 circumference. In Fig. 3763, A IS represents the plate to which the dial is attached; and the flat ring 
 C D, with the rest of the striking mechanism, lies between this plate and the dial. The four pulleys 
 are seen at E F G H. This ring has teeth cut in the part of the outer edge b nearest to the pendant, 
 and the rack may be thus turned by the wheel a, to which motion is given by turning the pendant. 
 At the lower part of this ring is a series of projecting pins, which, in the position shown in Fig. 3763, 
 act upon the projecting pallet i; whilst in the position shown in Fig. 3764, they act upon the pallet r. 
 Of these, the former is destined to strike the hours, and the other the quarters. The internal edge of 
 the ring is cut into two series of steps, of which the one seen on the left-hand side of each figure contains 
 twelve, and regulates the striking of the hours ; whilst the one on the right contains only four, and reg- 
 ulates the striking of the quarters. When the ring has had its position changed by turning the pen- 
 dant, it. is brought back again by a spring contained in the box or barrel Y ; the action of this spring is 
 communicated to the ring by a chain which winds off the barrel, passes between the pulleys U and W, 
 and is attached to the ring at X. Hence, in whichever direction the ring is turned, the chain will be 
 drawn off the barrel, and the spring put on the stretch, as seen in Fig. 3764; and the elasticity of the 
 spring will tend to bring back the ring to its previous position, shown in Fig. 3763. 
 
 37G3. 37G4. 
 
 The regulation of the number of strokes is effected by means of a snail, exactlv resembling that of a 
 clock. At I in either of the figures is seen the quarter-snail, placed on the axis of the minute-hand, so 
 as to revolve every hour, and cut into four steps. The same axle carries a projecting piece 2, which 
 acts on the star-wheel 1, Fig. 3764, in such a manner as to push it on to the amount of one-twelfth of a 
 circle at each revolution of the minute-hand ; consequently the whole star is made to turn once in the 
 twelve hours. To this wheel is attached the hour-snail, as seen in Fig. 3764; the common centre on 
 which they turn is marked at L, Fig. 3763. The hour-snail acts upon the bent lever P O Q, whose cen- 
 tre of motion is at 0 ; and the end P is always kept against the step of the snail by the spring seen in 
 Fig. 3763. In the position in which the lever is there shown, the snail having been removed, the end 
 Q of the lever is pressing against the last or lowest step of the flat ring, and consequently the ring can- 
 not be moved. But supposing the end P to be lifted by the snail to the 2d, 3d, 4th, or any other step, 
 the end Q will be raised to exactly the same amount, and will permit the ring to be turned from right 
 to left, until it is stopped by the contact of Q with the corresponding step of the ring. In exactly the 
 same manner the quarter-snail acts upon the steps cut in the inner edge of the ring at />, by means ot 
 the bent lever SRT, whose centre is R, 
 
 Now when it is desired to ascertain the hour, the watch is held in one hand and the pendant turned 
 from right to left with the other. This causes a corresponding motion in the ring ; and every pin, as it 
 passes the pallet i, gives an impulse to the hammer, which causes a stroke upon the sounding body. 
 The extent to which the ring may be turned, and consequently the number of pins allowed to pass the 
 pallet, depends upon the position of the lever POQ; and this, as just explained, is determined by the 
 position of the snail. Hence the ring is stopped just when as many pins have passed the pallet as cor- 
 respond with the step of the snail against which the end P of the lever is resting. After the hours have 
 been struck, the ring is brought to its original position by the spring contained in the barrel V, and the 
 pendant may then be turned in the opposite direction, so as to cause the other set of pins to act upon 
 the pallet k and to strike the quarters. Its motion in this direction is governed by the position of the 
 lever SRT, of which the end S rests upon the quarter-snail, whilst the end T checks the steps cut in 
 the ring at h. In the position represented in Fig. 3764, the ring has been turned as far as possible in 
 this direction ; for the end S rests upon the highest step of the snail, and has lifted the end so high 
 
836 
 
 WATER-CLOSET. 
 
 that the motion of the ring is not checked until it stops at the last step, by which time four pins have 
 passed the pallet, and four strokes have been made. 
 
 Denis new patent watch without a key. — There are two improvements which have recently been made 
 in the construction of watches, and patented, which will now be described. The daily recurrence oi 
 the act of winding up our watch, and its imperative necessity, renders it obviously desirable that the 
 power of doing this should be facilitated as much as possible ; and that whatever may be the situation 
 in which we may be placed, whether travelling, or in the dark, that we should be able to perform this 
 operation with the greatest ease and certainty : now the use of a key detached from the watch, and 
 requiring to be applied to a small hole, which must be seen to be used, is dispensed with by the im- 
 provement alluded to, so that the winding up of the watch may be effected in the dark by simply turn- 
 ing part of the pendant, by which the watch is attached to the chain to connect it with our person. 
 
 But this improvement is not the only one now made : thus much has been partially accomplished by 
 former artists, who, while they rendered the watch independent of a key for winding it up, suffered the 
 necessity for this adjunct, for the purpose of adjusting the hands, still to exist, and thus did not make 
 the machine quite independent of appendages of any kind. By a simple contrivance, which will now 
 be described, it will be seen that the adjustment of the hands can also be effected by the motion of the 
 pendant at the pleasure of the wearer, and that with a greater latitude than could be done under ordi- 
 nary conditions. 
 
 In Fig. 3 765, a is the knob next to the pendant-ring, 
 but in the improved watch independent of it, and mova- 
 ble with a rotatory motion like a common watch-key : 
 on the axis b of this knob there is a bevelled pinion 
 which acts by means of an intermediate wheel c on a 
 larger one d, which is carried on the axis of the main- 
 spring ; this completes the arrangement for simply 
 winding up the watch : that for setting the hands con- 
 sists of a pinion e attached to the arbor of the minute- 
 hand. This pinion, it must be observed, is free of the 
 wheel d, or, in technical language, not in geer with it ; 
 but it can be put so by means of another and equal 
 pinion / which is carried on an arm, or lever, moving 
 on a centre at g and terminating in a stud h, which 
 projects through the rim of the case ; if this stud is 
 moved by the finger from the pendant, the pinion / will 
 obviously be brought into geer with d, and thus will 
 impart the motion of that wheel to e when the hands 
 require setting ; but when the stud h is released, a 
 spring removes the pinion /from d, and the winding-up 
 part is detached as before. It must be mentioned, 
 that as it is requisite to be able to move the hands 
 either backwards or forwards, the wheel d is made to 
 admit of motion from the knob a in either direction, for 
 this purpose. Since the winding up must always take place in the same constant direction, there is a 
 ratchet and click of the usual principle connected with the wheel d to admit of this double motion : by 
 this arrangement also, the injury to the watch produced by over-winding is guarded against. 
 
 It will be inferred from the foregoing description that the frequent necessity for opening the watch is 
 done away ; hence results another, and not the least improvement effected by the contrivance : in the 
 old construction of the watch-case, dust will penetrate to the interior of the watch, however seldom it 
 may be opened, through the number of passages necessarily consequent on the existence of hinges in 
 the case ; these being dispensed with in the watch now described, the glass and case are as nearly air- 
 tight as possible, while the dust which makes its way in the ordinary watch to the works each time the 
 case is opened for the purpose of winding up, or of setting the hands, is now altogether excluded ; thus 
 cleaning the watch will not be so frequently required as heretofore. 
 
 WATER-CLOSET — By G. Jennings. This closet is intended to remedy the defects of the pan and 
 valve closet. It has neither the usual metal pan or valve, so that no chamber is required, which prevents 
 displacement of pure air when used — an evil so justly complained of in pan or other closets. 
 
 376G. 3765. 
 
 3707. 3768. 
 
 The raising of the handle, as shown in Fig. 3768, causes the water to fall from the cistern to the 
 closet, and suddenly discharges the contents of the basin with all its force through a four-inch India-rub- 
 ber pipe, flushing, as it is termed, the trap and soil-pipe each time the closet is used. The lowering of 
 the handle, as shown in Fig. 3767, compresses the tube, and retains the water in the b""’" ' T ’k« 
 
 water passes off through the overflow pipe, which also regulates the proper quat: 
 letained. 
 
WATER-METRE. 
 
 «37 
 
 This closet in its action is perfectly silent, as the metal-flaps fall without noise against the India-nib- 
 ber tube. It is also free from all complication ; and a fresh piece of India-rubber tube, if ever needed, 
 will make the closet as good as new. 
 
 WATER-METRE — By W. II. Lindsay. The invention of an instrument that will, on inspection, 
 show accurately the amount of water evaporated during any given time — as, for instance, during a voy- 
 age — by a steam-boiler, is a desideratum which has long been sought after. 
 
 The water-gage represented in Figs. 3769 and 3770 is the invention of William H. Lindsay, con- 
 structing-engineer, New York, who has, after a large outlay of time and money, succeeded in producing 
 a durable and critically accurate instrument, and is the only one yet brought into practical operation 
 which can lay claim to that title. It has been subjected to the most thorough and repeated trials, un- 
 der the supervision of many of our most distinguished engineers, and a board of officers appointed by the 
 Navy Department to examine and leport upon its merits. The trials took place after it had been in 
 
838 
 
 WATER-METRE. 
 
 operation more or less every day for the previous five months. On measuring accurately the quantity 
 of water passed through it, in the tanks that received it, and comparing the amount as indicated by the 
 instrument, the difference on nine experimental trials, under different or varying circumstances, was 
 found not to exceed 30 cubic inches in one hundred thousand. 
 
 By the use of this instrument on board steam-ships, the owners will be enabled to place themselves in 
 as advantageous a position, in a pecuniary point of view, as that of the Cornish mine-owners, who some 
 years since adopted the system of registering the duty performed by their engines, and the amount of 
 fuel consumed ; in other words, the work done in relation to the fuel consumed is registered. This ob- 
 ject is accomplished there by means of a counter, which merely registers the number of strokes made 
 by the engine ; but this expedient will only answer where the load upon the engine is constant and 
 easily measurable, but is of no avail in a steam-vessel, where the load is continually var 3 'ing ; which can 
 only be done by measuring and recording the quantity of water evaporated by the boilers, and con- 
 verted into steam, which is the measure of the power exerted by the engines. 
 
 The best proof of the saving in fuel derivable from the plan of registering the duty performed by 
 steam-engines, consists in the enumeration of the wonders it has already done. According to a report 
 made by a committee of the House of Commons appointed to investigate the matter, it appears that the 
 Cornish mine-owners, even in their limited operations, are saving the sum of $400,000 per year, by the 
 simple expedient of registering the duty of their engines. If such a saving can be realized by this sys- 
 tem out of the contracted sphere of Cornish engineering, the results that would ensue by its adoption in 
 our ocean steam-ships are incalculable. Such a practice insures a rigid attention to their duties on the 
 part of the engineers and firemen, as any negligence will be sure to tell to their disadvantage. Its adop- 
 tion puts all the engineers upon their mettle, and induces an emulation, out of which improvement can- 
 not but spring, with corresponding advantages resulting to the owners. Yet the saving of fuel in the 
 case of steam navigation, important as it would be, is not the greatest benefit that would be derived. 
 The powers of steam navigation would be extended, and its profits correspondingly augmented. Re- 
 quiring a less amount of fuel to perform the same duty, they could carry more cargo, and the growth of 
 our steam marine would just be in proportion to the extension of the limit which now hinders its develop- 
 ment. It is needless, however, to dwell further on the advantages derivable from the system of regis- 
 tration, as they must be conspicuous enough to every one who gives attention to the subject, the ac- 
 knowledgment of which has been made by its adoption in the naval service, by order of the Navy De- 
 partment. A series of experiments will shortly be commenced at one of our navy yards with one of 
 these instruments, by a board of officers appointed by the Department, for the purpose of establishing a 
 standard of evaporation due the different varieties of coal used for the generation of steam, for the use 
 of the naval and mercantile marine ; also to institute a series of experiments to ascertain the relative 
 merits of boilers of different construction, which may lead to the solution of the problem, what are the 
 true principles which should govern their construction in every respect ; and determine, beyond all cavil, 
 the best-constructed boiler in use at the present time. The results that may be arrived at by the use 
 of this instrument will be a subject of much importance to all concerned in steam navigation. 
 
 Having given an outline of the use of this important invention, we will proceed to give a description 
 of the figures, &c. : — Fig. 3710 is an elevation. Fig. 3769, sectional do. The figures are lengthened 
 out, with the view only of showing the metre’s general arrangement, without reference to the economy 
 of space that may be attained by a compact arrangement of its several parts. 
 
 Literal references. — D, connecting pipe from the feed-pump of the engine to the drop-valve chest, G ; 
 E. an overflow-valve chest bolted on the pipe E ; F, air-chamber ; G, drop-valve chest bolted to the 
 forcing metre-chamber or cylinder H ; T, plunger or ram working in the cylinder H ; R, metre-cylinder ; 
 L, plunger working in the metre-cylinder — the tYvo plungers being connected by a coupling-rod ; M, 
 metre valve-chest bolted to the cylinder R; N, stop-cock on the pipe O leading to the boiler ; R, feed- 
 pipe from the hot well bolted to the bottom of the valve-chest M, for supplying the metre-chamber R ; 
 P, side-frames, to which the cylinders H and R are bolted. 
 
 b, valve in chest E, loaded by means of the springs attached to the cross-head on the valve spindle ; 
 
 c, drop or cut-off valve in the chest G'; g, cut-off valve spindle passing through a stuffing-box on the 
 cover or bonnet of the drop-valve chest ; d , stud keyed on the spindle g ; e, an inclined slide receiving 
 motion from the connecting link y. It works in a slot in the shde-piece that springs in under the stud 
 
 d. When the valve c rises, and when it is drawn down by the rod y, it draws back the slide-piece from 
 under the stud d, thereby allowing the valve c to fall on its seat, and prevent the return of any more 
 water from the forcing-cylinder H through the pipe D into the engine feed-pump, during its exhaust 
 stroke, h 2 li 2 , seat on the frame/, on which the drop-valve slide (not shown) works, and through which, 
 at the back part, the inclined slide e also passes ; / stand for the seat li 2 li 2 , its lower end being bolted 
 on the bonnet of the chest G. Its upper end is curved, the valve-rod g working through it, which confines 
 the valve-rod to its place. There is a spring not shown fastened to the inside of the frame in its curved 
 portion, the lower end of which being in contact with a small stud on the slide-piece working on the 
 seat h 2 li 2 , springs it under the stud d. When the valve-rod g rises, by the water lifting the valve c on its 
 passage to the cylinder H, the slide-piece retains the valve c, leaving a free passage for the water to and 
 from the cylinder H and the engine feed-pump during the force and exhaust strokes of the feed-pump 
 plunger, until such time as the plungers T and L have completed their required amount of force and 
 exhaust travel, when, by the motion-rod l, on which is keyed the bracket s, in the slot of which is ad- 
 justed the pin t, coming in contact with the arm u, thereby giving motion to the arm to, the connecting 
 link y, and the inclined slide e, the slide-piece is withdrawn from the under side of the stud d, and 
 the valve c drops on its seat, having arrested the motion of the plungers T and L. It remains at rest 
 until the feed-pump plunger again commences its force stroke, when the valve rises as before, and is 
 again locked by the slide-piece. The motion-rod has the same motion as the plungers T and L, being 
 worked by a cross-arm from the plunger coupling-rod, (not shown,) the end of which works on the 
 guide-rod k. The arm i being bolted to the cross-arm at the upper end, and keyed to the motion-rod 
 
WATER-PRESSURE ENGINE. 
 
 839 
 
 at the lower, the travel of the plungers is recorded by means of the rack, keyed on the rod b, giving 
 motion to the segment n, which works freely on the spindle n 2 , on which the arm is keyed. The mo- 
 tion of the arm is communicated by the link h to the counter arm r, which has a slot in it, by which 
 the required length of counter arm may be obtained by means of a pin having a nut on the back. 1, 
 feed-valve in metre-chest ; 2, delivery-valve in same. 
 
 On reference to the sectional figure, it will be perceived, that by the drop-valve c and the deliverv- 
 valve 2 being open, that the cylinder H is receiving water from the engine feed-pump during a force 
 stroke, and that the metre-cylinder R is discharging, by the advance of the plunger L into it, a quantitv 
 of water through the valve 2 and the pipe 0, provided the stop-cock N is not closed, equal to its area 
 of surface and length of travel. But, supposing all the parts in the position as represented, that the 
 stop-cock should now be closed, there being no passage for the water from the cylinder R, the plungers 
 are at once brought to a state of rest, the water from the feed-pump finds -an escape by lifting the 
 loaded valve b, and passing off by the overflow-pipe ; so in like manner if the stop-cock N is only part 
 open, the plungers T and L will only move a distance equal to the quantity of water received into the 
 cylinder H, the rest going to waste by the valve b. 
 
 On the engine feed-pump plunger commencing its exhaust stroke, the delivery-valve 2 having closed, 
 the pressure of the water from the hot well causes the feed- valve 1 to rise, admitting of a supply to the 
 cylinder as the plunger L recedes, by reason of the plunger T being acted on by the vacuum caused 
 by the exhaust stroke of the engine feed-pump plunger, and the pressure of the water from the hot well 
 on the plunger L, by the plunger T following the vacuum, the water in the cylinder II during the pre- 
 vious force stroke of the engine feed-pump is returned to it on the exhaust ; and in case that only a part 
 of the water discharged by the feed-pump during its previous force stroke should have entered the 
 cylinder H, by reason of the stop cock IST being partly closed, the rest having escaped by the valve b, 
 then the cylinder H first returns all it received, the valve-rod g is disengaged, the valve c drops, and the 
 deficiency is supplied to the feed-pump by the feed-pipe from the hot well. 
 
 From the above, it will be seen that the travel of the plungers L and T is dependent on the quantity 
 of water received during each stroke of the engine feed-pump by the cylinder H, and the quantity of 
 water displaced from the cylinder, and thence into the boiler, is dependent on the area of surface and 
 length of travel of the plunger L ; from which it follows, that if the travel of the plungers is correctly 
 recorded, we can at any time ascertain, by inspection of the counter-face, the actual amount delivered. 
 
 WATER-PRESSURE ENGINE. The first engine erected in England with cylinder or piston- 
 valves, was that put up in the Alport mines, Derbyshire, in the year 1842. This was a single cylinder 
 engine. Its success was complete, and others were erected on the same plan. But in 1845, a com- 
 bined cylinder engine was designed, and erected by the same engineer, which is found practically to 
 have several advantages for such large supplies of water as that consumed by the pumping-engine, ol 
 which we subjoin accurate reductions of the working-drawings. 
 
 3773. 
 
 Fig. 3771 is a front elevation of the combined cylinder engine. Fig. 3772 is a sectional view, ana 
 Fig. 3773 is a general plan. PC is the bottom of the pressure column, 130 feet high, and 24 inches 
 internal diameter. C C are the combined cylinders, each 24 inches diameter, open at top, with hemp- 
 packed pistons a, Fig. 3772, and piston-rods m , combined by a cross-head n, working between guides in 
 a strong frame. The admission throttle-valve is a sluice-valve, shown at o, Fig. 3771, and between the 
 letters b and e in Fig. 3773. The main or working valve, is a piston g, 18 inches in diameter, Fig. 3772, 
 with its counter or equilibrium piston above. The orifice for the admission of the pressure water is 
 netween the two pistons. The intermediate pipe a is a flat pipe, into which numerous apertures lead 
 from the valve-cylinder, seen immediately under g, Fig. 3772. The valve-piston is in the position for 
 discharging the water from the cylinders through the pipe e, Fig. 3772, by the sluice-valve k. 
 
 The valve-geer is worked by an auxiliary engine h, by means of the lever v. The auxiliary engine- 
 valves, are piston-valves in the valve-cylinder i, Figs. 3772 and 3773, communicating with the pressure- 
 pipes by a small pipe, provided with cocks, as shown in Fig. 3773. The motion of the auxiliary engine- 
 valves is effected by a pair of tappets t’ t", set on a vertical rod attached to the cross-head n. These 
 tappets move the fall-bob b, by means of the cauti-lever t, Fig. 3771, the other end of the lever beins 
 
840 
 
 WATER-PRESSURE ENGINE. 
 
 linked to the rod s, Fig. 3772, (s, Fig. 3771, is misplaced,) -which again is linked to the auxiliary piston- 
 valve rod. 
 
 The play of the machine is now manifest. It is in every respect analogous to the Harz and Huel- 
 goat engines, described by Weisbach. The average speed of the engine is 140 feet per minute, or 7 
 double strokes per minute. This requires a velocity of something less than 2-^r feet per second of the 
 water in the pressure-pipes ; and as all the valve apertures are large, the hydraulic resistances must be 
 very small. The engine is direct-acting, drawing water from a depth of 135 feet, by means of the 
 spear ww, Figs. 3771 and 3772. The “box,” or bticket of the pump, is 28 inches in diameter, so that 
 
 3771. 
 
 the discharge is 266 gallons per stroke, or when working full speed, 1862 gallons per minute. The 
 mechanical effect due to the fall and quantity of water consumed is nearly 140 horse-power. The 
 mechanical effect involved in the discharge of the last-named quantity of water is nearly 74 horse- 
 power, so that supposing the efficiency of the engine and pumps to be on a par with each other, the 
 
 efficiency of the two being r j, = 71'15, the efficiency of the engine alone r> 
 
 1 + Vi 
 
 1 + T1 
 2 
 
 •85, oi 
 
 n the language of Cornish engineers, 85 per cent, is the duty of the engine. 
 
WATER-WHEELS. 
 
 841 
 
 WATER-WHEELS — -Theory and Construction of. Although in localities where mineral reservoirs 
 of motive power are convenient, the ever-available 1 steam-engine has much diminished the importance 
 of hydraulic movers, these must always continue to be the most economical, and therefore the most 
 frequently resorted to, in situations where the liquid element can be attained in sufficient abundance, 
 and under the necessary circumstances to answer the conditions contemplated. A waterfall is rendered 
 available comparatively without labor, and furnishes its supplies without the intervention of human aid 
 The energies of the steam-engine, on the contrary, can be commanded in any situation, only by the 
 influence of the miner ; and in localities much removed from sources of fuel, can only be sustained at 
 an expense which falls heavily upon the operations to which they are subservient. That expense, it is 
 true, is continually being diminished, and by means of the steam-engine itself, in its character of a car- 
 rier ; but no happy discovery, no possibility, can reduce it to the minimum at which our water-runs are 
 maintained. 
 
 But while water-power has the advantage of economy, where it is abundant and constant, in other 
 localities where it is more immediately dependent upon the condition of the seasons, it is under the dis- 
 advantage of being less certain, and less under control, than the more artificial agency developed in the 
 steam-engine. It is this independence of time and season, of circumstances and locality, which mark 
 the great superiority of this potent creation of engineering skill, and which, in its multiform applications 
 and applicability, have invested it with an importance and an interest which success seems only to 
 stimulate and render more intense. The complexity of parts, and the diversity of combination, offer a 
 scope for the exercise of ingenuity, alike highly inviting to the theoretical and the practical mechanic. 
 The steam-engine, even as a stationary power, is, moreover, of recent origin ; and contemplating the 
 phases which it has already assumed, in connection with the general feeling that its energies have not 
 yet been fully developed, it is not matter of wonder that it has diverted attention from the less inviting 
 problem which we are about to discuss. Water-power is an old, if not an antiquated subject, on which 
 the light of modern improvement has been but feebly reflected since the days of Smeaton. With a few 
 exceptions, it has been abandoned to the management of those who recognize in it no principle, and no 
 scope for improvement ; and whose practice is not more opposed to improvement than it is empirical 
 and opposite to all true principle. 
 
 The fact that water-power is an agency which cannot be augmented at pleasure, and which, in most 
 situations where it is employed, has a full share of duty imposed upon it, renders it desirable that the 
 best means of economizing it be adopted. This implies a knowledge of some of the fundamental prin- 
 ciples of hydraulics, in addition to. that acquaintance with the general laws of mechanics which every 
 engineer is assumed to possess. It is with the view of placing the subject in a distinct and concise 
 form, and of pointing out precisely those principles which ought to guide the practice of the engineer 
 in his dealings with this agency, that we undertake a brief exposition of the general problem. Under 
 the title assumed, is implied the economy of water-power, and the various means of rendering it avail- 
 able for purposes of industry. Without avoiding those abstract questions which beset the subject, and 
 which imply some acquaintance with elementary analysis, we shall endeavor to keep in view that 
 theory is valuable only in its relations to practice. 
 
 Characteristic varieties of water-wheels , and the theory of their action. — By far the most numerous, 
 and, therefore, important order of hydraulic movers, are those which come under the denomination of 
 vertical wheels , from their movement being in vertical planes, and their axis of rotation consequently 
 horizontal. Of these we have three varieties — named according to the points at which the water is 
 received upon the periphery — overshot, undershot , and breast wheel. This last is further distinguished 
 as high and low breast, according as the water is received upon the wheel above or below the horizontal 
 plane of the axis. When the point of reception approaches the lowest point of the circle, it becomes 
 an under shot-wheel ; and on the contrary, when the water is laid on within a few degrees of the sum- 
 mit, it takes the name of overshot. 
 
 A second order, of which the varieties are more numerous, and even less distinct, come under the 
 denomination of horizontal wheels, because they move in planes parallel with the .horizon, and conse- 
 quently have their axis of rotation vertical. Of these, the best known types are the reaction-wheel, 
 the turbines of Burdin, Fourneyron, and Jonval, the tub-wheels of America, (the moulines a cuve of the 
 French,) and the wlieelets common in the south of France (in Provence and Dauphine), and which con- 
 sist simply of a series of spoon-shaped (and somet imes flat) paddles or floats, set on the periphery of a 
 strong wooden axis, and against which the water is projected from a conical adjutage. The danaide, 
 better known to theory than practice, belongs to the same order. 
 
 The effects of these different varieties of wheels arise from three sources — weight, impulse, and re- 
 action. But in stating these as the primary and simple elements of hydraulic power, it is to be re- 
 marked that we very rarely find the effect reducible to a single mode of action ; more commonly we 
 find two, and sometimes even the three acting simultaneously, and not unfrequently in nearly equal 
 degrees. Centrifugal force is also an element which in most forms of wheels requires to be appreciated ; 
 and in some constructions — the reaction-wheel, for example — it is the most difficult influence which 
 enters into the calculation of the ultimate effect. 
 
 Directing our attention, in the first instance, to the element of weight, it is easy to prove that when 
 a given volume of water descends through a known height H, its effect, as a mechanical agent, will be 
 expressed by the product of the weight into the height H fallen through. Asa familiar illustration, in 
 lieu of a more precise demonstration, take the case of a horse drawing a load upon a horizontal road, 
 and suppose that the movement is uniform over a certain distance : the constant effort exercised by the 
 ) orse may manifestly be measured by a dynamometer placed between the horse and the load. Sup- 
 posing this done, and that the number of lbs. indicated by the instrument as the force expended by the 
 animal in moving the load is P, and that the distance travelled over is D feet ; the product P X D, or 
 simply P L, will be a measure of the amount of effort exercised by the animal in passing over the given 
 distance D. Now if, in place of the horse, we suppose a weight of W lbs. to be attached to the load. 
 
842 
 
 WATER-WHEELS. 
 
 by a rope passing over a pulley fixed in the mouth of a pit, of the depth H, equal to the length D, thl 
 pulley being assumed to have no friction, and the rope no weight, (conditions which can be virtually 
 attained,) the weight W, which is a measure of the constant effort exerted by the animal, will descend 
 and drag the carriage along the level road with the same uniform velocity, and arrive at the bottom of 
 the pit at the same moment that the horse would have arrived at the extremity of the distance D. In 
 both cases, the carriage passes over the same space and with the same velocity ; the weight W is there- 
 fore capable of effecting all that the horse had done ; as a prime mover, it is therefore identical. It has 
 given the same quantity of action W X II or W H = P D in the same time. Its dynamical effect may 
 therefore be expressed in terms of the power of the horse, as a known unit. And in general the power 
 developed by any mover, animate or inanimate, may in like manner be measured by that of a weight 
 W descending through a certain height H, and expressed by the product W H. 
 
 Keeping this principle in view, it is further obvious that the greater the height through which the 
 weight descends, the greater will be the effect produced. But as a current of water may be regarded 
 as a continuous succession of weights, descending from the higher to the lower level, it is necessary to 
 ascertain the rate of succession — in other words, the measure of the weight which descends in a given 
 unit of time. Let that unit be 1 minute, and let the quantity of water flowing be 500 cubic feet, which 
 multiplied by 624, the weight in lbs. of a cubic foot of water, gives 31,250 lbs. as the weight which has 
 descended in a minute. Further, let it be supposed that the whole height H, through which it descends, 
 that is, the whole height of the fall or head , is 120 feet; if this quantity of water be made to act upon 
 the circumference of a gigantic overshot-wheel, so constructed as to be free from all those detrimental 
 influences to be hereafter considered, and the wheel be attached by a suitable connection to a train of 
 carriages upon an incline, which by experiment is found to require the application of a force (measured 
 dynamometrically) of 31,250 lbs. to move it through 120 feet in a minute, then, the power and resistance 
 being equal, the water will give motion to the wheel, and descend with it through the height of a fall 
 equal to 120 feet in the same time that the load is moved through an equal distance upon the incline. 
 In this case we have manifestly WH = PD, since W = P, and H = D. The first of these conditions 
 only is necessary to establish an equality of dynamical action. Let us assume the height of the fall to 
 be reduced to 30 feet, and the force necessary and sufficient to drag the train of carriages up the incline, 
 with a velocity of 120 feet a minute, to be only 78121- lbs., the other conditions remaining unchanged, 
 the quantity of water constantly in action upon the circumference of the wheel will be 4th of 31,250 
 lbs. = 78124 lbs., since the rate of descent is 120 feet per minute ; and the distance 4th of 120 feet, or 
 30 feet. In this case, D = 4 X H, and W = 31,250 lbs. of water expended in the unit of time is equal 
 to four times the load moved ; but 4 W X H = 4 P X D is W II = P D, by cancelling the common 
 multiplier 4- 
 
 The dynamical force of a current of water is therefore correctly represented by W H lbs. per minute ; 
 and since the height of fall H feet is independent of the time, W lbs. must express the weight of water 
 which descends in a minute. A stream on which there is a fall of 30 feet, with a supply of 500 cubic 
 feet of waiter per minute, will afford the same amount of power as another stream of 1000 cubic feet 
 with a fall of 15 feet, the product W H of the two factors being the same, whether we take 30 X (500 
 X 624), or 15 X (1000 X 62-4). 
 
 In thus estimating the motive force of a current of water, the height H is the difference of level be- 
 tween the surface of the water at the higher and low T er points between which its power is developed. 
 This is termed the fall, and is either real or Active : it is real when the fluid descends abruptly from a 
 higher to a lower level, and Active when it acts in virtue of a velocity of motion due to that height. Thus 
 if a current, flowing in an inclined channel, be ascertained by experiment to have a uniform velocity of 
 12 feet in a second, then we know, from the laws of falling bodies, that the fictive head is 2-25 feet 
 nearly, and is found from the formula Y = g H. In this formula, V expresses the velocity of the 
 current in feet per second, and g = 32-2 feet the velocity communicated to a falling body by gravity at 
 the end of the first second, when it falls freely. H is the height capable of generating the velocity V, 
 V a 
 
 and is therefore represented by — 0'0155 V 2 ; and if s be the area of the cross section of the fluid cur- 
 rent in square feet, then the weight of water passing a given point in a second will be 62'5 s V; and 
 therefore the whole dynamical force in a second will be expressed by 
 
 62-5 s V X 0-0155 V 2 = 0'97 s V 3 , 
 
 and this result multiplied by the number of seconds in a minute, the unit assumed in speaking of the 
 dynamical value of a real fall of H feet, gives W H = 58 23 s V 3 . 
 
 In illustration : let the mean velocity of a current be 10 feet per second, the mean depth 2 feet, and 
 the mean width 15 feet ; then V 3 = 1000, and s = 30 square feet ; 
 
 . • . W H = 58-23 X 30 X 1000 = 1746900, 
 
 the dynamical force of the current, of which the fictive head is 0 0155 V 2 , equivalent to 1'553 feet, and 
 the quantity of water flowing per minute is 1,125,000 lbs. 
 
 Tiie fictive head of a stream flowing in an inclined channel may then be determined in terms of a 
 real or vertical head, and measured accordingly. They are, indeed, mutually convertible ; and were it 
 not that the expression W H is arithmetically more convenient than 58-128 s V 3 , we might in every 
 case determine H in terms of V, and employ the latter formula in our calculations of the power of a 
 
 ivaterfall. Thus generally II = : — ; therefore, if II be known, the value of Y can be readily deter- 
 64'4 
 
 mined ; and conversely, if V be ascertained, the corresponding value of H may in like manner ba 
 found. 
 
 We have hitherto employed these expressions abstractly; but in speaking of the dynamical force o; 
 
WATER-WHEELS. 
 
 843 
 
 a fall of water, it is found convenient to introduce a unit of comparison by which the amount may be 
 more readily conceived. The mind does not readily apprehend the value of a product, even of such 
 magnitude as 1,746,900 ; and it is often necessary to deal with much higher results. In this, as in all 
 other estimates of mechanical power on a large scale, the unit adopted is the horse-power, reckoned at 
 150 lbs. raised through a height of 220 feet in a minute, or 33,000 lbs. 1 foot high per minute — as from 
 the bottom of a mine by a rope passing round a pulley. This is the unit introduced by Watt in rating 
 his steam-engines, and is supposed to have been taken as the maximum work of the London dray 
 horses. The estimate is found to be a third part too high, as applied to draught horses generally ; but 
 as a measure of dynamical force, when applied to inanimate sources of power, it is unexceptionable on 
 that account. The object is served by a definition of the unit ; and horse-power is a name less objec- 
 tionable than any others which have been proposed, unless we are to except the cheval vapeur of the 
 French writers. 
 
 We have already shown that the magnitude of the individual factors of the product W II may rel- 
 atively change without affecting the result. Now, in the estimate of the horse-power, we have taken 
 150 lbs. = W raised (or descending) through 220 feet = H in a minute ; but these numbers will mani- 
 festly give the same product by multiplication as 33,000 lbs. — W, raised (or descending) through 1 
 foot = H in a minute. This affords the simpler enunciation, and is that uniformly adopted. 
 
 To estimate, therefore, the moving force of a current of water in units of this kind, it is only neces- 
 sary to divide the product W H by 33,000, and the quotient will indicate the equivalent in horse-power. 
 Thus in the example above, we find W H = 1,746,900 dynamic units; which divided by 33,000 gives 
 52'936 as the horse-power of the current. 
 
 The same result may, of course, be obtained by taking the reciprocal of 33,000 = ‘000030,303 as a 
 multiplier. And if we take Q to represent the number of cubic feet of water supplied in a minute, we 
 
 shall have W = 62'5 Q, and, therefore, 
 
 62‘5 Q II 
 33,000 
 
 QH 
 
 523 
 
 ■0018,939 QHwill express the horse-power 
 
 of the current. Thus in the preceding example, the fall due to a velocity of 10 feet per second is 1 ‘5 5 3 
 feet = H, and the quantity of water supplied per minute will be (2 X 15 X 10) X 60 = 18,000 cubic 
 feet - Q. Then ‘0018939 X 18,000 X 1'553 = 52‘94 horse-power as before determined. 
 
 It may also be here observed, that 33,000 lbs. raised a foot in a minute being the same as 550 lbs. 
 raised to the same height in a second, if we take w to represent the weight of water supplied in the 
 
 WH 
 
 smaller unit of time, then will ■ = ‘00182 W H represent the horse-power of the stream. Thus in 
 
 WH 
 
 the preceding example, w = 300 X 62J = 18,750 lbs. ; and II = 1‘553 ; therefore, ■ ■ = 52‘94 horse- 
 
 power as before. 
 
 Also, since 550 lbs. = 8 8 cubic feet of water, if q be the number of cubic feet furnished per second, 
 then 2-— will in like manner represent the horse-power of the current. 
 
 O'O 
 
 As all calculations of the velocity are referred to a second as the unit of time, these forms of expres- 
 sion will sometimes be useful in our subsequent investigations, and may be borne in mind. 
 
 We have hitherto spoken of the power of the water; but in the application of a motive power by 
 means of machinery, we in no case realize the theoretical effect. To produce an effect by a machine, 
 is to overcome the resistances continually and periodically reproduced in a direction opposed to the 
 direction of the moving force during the time of its action ; but in this a certain loss invariably occurs. 
 Thus, confining our attention to the agency under consideration, all the force W H of a current of water 
 directed upon the buckets of a water-wheel does not take effect. A part of the water W commonly 
 escapes, especially in low breast and undershot wheels, between the wheel and the arc by which the 
 water is confined ; and a part of the head H is also lost, both on the entrance of the water upon the 
 wheel and on its leaving it. To these sources of loss we must generally add the amount of motive 
 force annihilated by the counteraction or hack lash of the water in striking the buckets, and the con- 
 traction of the stream at the penstock. These circumstances, to which we shall return, prevent the 
 transfer of a certain amount of the power possessed by the water to the wheel ; but there are, besides, 
 absorbing influences which diminish the useful effect of the power actually developed. In the machine 
 itself, we have the friction of the journals ; and if the velocity be high, as in horizontal wheels working 
 under high falls, the resistance of the atmosphere becomes a sensible quantity. At the geering by 
 which the power is transmitted to the working points, another loss takes place by the friction and 
 shocks of the teeth — individually very small, it is true, but being constantly and often repeated, the 
 sum becomes an appreciable quantity. 
 
 These resistances, which for our present purpose it is sufficient to indicate, being in some part essen- 
 tial to every arrangement of mechanism, have in consequence obtained the name of passive resistances, 
 in contradistinction to active resistance, by which we understand the useful effect developed. The sum 
 of the two — that is, the whole resistance overcome by the machine, active and passive, useful and non- 
 productive — is its dynamic effect, and is less than the dynamical effect of the water expended by the 
 amount of loss incurred by the factors W X H. 
 
 From what has been observed, respecting the development of mschanical power, its measurement 
 Deing the force requisite to elevate a given weight through a known space in a defined unit of time, it 
 is manifest that the higher the velocity of the machine, the greater will be its efficiency, supposing 
 always the resistance overcome to preserve the same intensity. If, therefore, we put w to represent 
 the weight equivalent to the useful or active resistance, and v the velocity with which it is overcome, 
 also w' X v' to denote the same quantities in respect of the passive resistances, we shall have as the 
 
844 
 
 WATER-WHEELS. 
 
 expression of the ■whole dynamical effect of the machine, wv v'. But as all resistances, active 
 and passive, upon the machine are reducible to the common velocity v, we may put W to represent 
 their entire sum ; and, therefore, denoting by E the whole dynamical effect, we shall have E = W «. 
 In words : the effect of the mover is equal to the resistances overcome. 
 
 From this, we observe that the effect does not depend upon the magnitude of the individual factors, 
 but upon that of their product. By means of geering, the working speed may be made a hundred or a 
 thousand times greater or less than that of the first mover ; but when this is the case, the weight ele- 
 vated will be correspondingly diminished or increased in amount, agreeably to the maximum univer- 
 sally recognized in mechanics, that whatever is gained in speed is lost in force, and vice versa. 
 
 The factor v is in practice easily ascertained by observation ; but W being the sum of resistances 
 opposed to the movement of the machine, and often consisting of many particulars imperfectly ascer- 
 tained, and only ascertainable by direct experiment, usually of some difficulty, this factor, and conse-' 
 quently the whole effect E, does not always partake of that certainty which is desirable, in comparing 
 the work done with the power expended. But this last, which we have represented by W H, being 
 always greater than E, we know that whatever may be the efficiency of the wheel, these forces must 
 have the relation E = in W H, in which m is a fraction less than 1, but different in different cases and 
 conditions, and only determinable by direct experiment. Taking the force expended, viz., ¥H = 1, 
 the coefficient m will express the ratio of the effect realized in the active and passive resistances of the 
 mover to that force. It can never equal 1, for then the whole moving force would be realized by the 
 wheel, which cannot possibly happen by any adaptation hitherto discovered ; much less can it exceed 1, 
 which would imply that the power realized is greater than that expended. The values which it bears 
 in particular cases will be subsequently investigated at considerable length, taking as the basis of dis- 
 cussion the numerous experiments which have been directed to its determination. In the mean time, it 
 will be sufficient to observe, that it very rarely exceeds 0 80, and not unfrequently, in undershot-wheels, 
 it falls below 0’25. In wheels coming under the denomination of high breast and overshot, the common 
 value ranges from 0-75 to 0-66. 
 
 The formula E = a WH is general ; it applies to any hydraulic mover under any circumstances, 
 and, therefore, the effect and producing cause may always be thus compared. When the fall is Active, 
 we have seen that it may be determined in terms of H, from the known relations of the velocity Y 
 generated in the current, to the generating head H. But in the case of an undershot-wheel acting by 
 a Active head, although the formula of ultimate comparison remains the same as for an overshot-wheel 
 acting under a real head, the mode of action is different, and requires a separate consideration. Taking 
 a case of the most simple kind, in which the wheel is furnished with radial floats, and acts in a confined 
 rectilineal course, in which the current of water flows with a velocity of V feet per second, it is obvious 
 that the motion of the floats must, under the supposition of the wheel beiffg burdened, be less than Y 
 when impelled by the current ; since it is clear that the fluid could have no effect upon them if they 
 moved at the same velocity, and would retard rather than impel the wheel at any higher velocity. 
 Moreover, in impelling the floats at a given velocity v, there must remain in the water, after it has 
 passed the wheel, a certain velocity which is always greater, and cannot manifestly be less than v. If, 
 according to the supposition, the floats so completely occupy the watercourse that no particle of the 
 fluid can pass without acting upon them, the velocity retained by the current would evidently be the 
 difference between the initial velocity V, and that imparted to the surfaces opposed to its motion. But 
 this condition, although not actually, is virtually fulfilled in every case analogous to that assured, how- 
 ever imperfect the arrangements in scheme and construction. Although a highly mobile fluid, there is 
 a certain cohesion among the particles of a current of water, by which an equilibrium of motioii is, if not 
 uniformly maintained, at least quickly established in cases of disturbance. The interruption offered tc 
 one portion of the mass is speedily communicated to the whole. The uninterrupted particles, by the 
 mutual cohesion existing in the mass, act upon those to which the interruption has occurred, and there- 
 by reciprocally communicate and lose a portion of the velocity which they possessed. An equilibrium 
 may not be thus instantaneously established. Like other ponderous bodies, the fluid particles possess 
 inertia, and, therefore, require time to receive and communicate motion ; but the action is no less certain 
 and essential to the conditions assumed. We may, consequently, without risk of error, presume that 
 in all cases the velocity retained by the water after it has acted upon the float of the wheel, will be 
 fairly expressed by V — v. This velocity is, moreover, lost as respects the efficiency of the wheel: it 
 has produced no effect. Now, from what has been before stated, we know that the head equivalent to 
 
 V 2 
 
 the initial velocity V of the current may be expressed by — — ; and extending the same principle to the 
 
 ~ 9 v 2 
 
 velocity v communicated to the wheel, the head equivalent will be expressed by— — ; and the head lost 
 
 J (V — -vf 
 
 in consequence of the unemployed velocity V — v will, in like manner, be represented by — . The 
 
 vertical section of the stream being, therefore, designated as before by s , the whole weight of water 
 acting upon the wheel, in a second of time, will be represented by 62'5 s V, and this multiplied by 60 
 will be the quantity acting in a minute = W. The dynamical effect of the impulse will; therefore, be 
 expressed by 
 
 ( V 2 d 2 (V — A 2 \ W 
 
 — J reducible to — (V — v)v 
 
 2 3 *3 2 g ) g K 
 
 by performing the operations indicated. And designating by li h' h", the heights of head due to the 
 three velocities Y, v, and V — v, we have the equivalent expression 
 
 W Ih — h' — h”\ 
 
WATER-WHEELS. 
 
 845 
 
 The two last terms in the parentheses manifestly diminish the effect produced. Were they zero, this 
 effect would then be W h, which is the whole dynamic force of the current, since h represents the total 
 head due to the velocity V. In order that the first of the two last terms may be zero, it i*necessary 
 that v = 0 ; and on this supposition, the whole expression vanishes, showing that no effect is realized — 
 which is manifestly the case where the wheel has no velocity. The expression further shows that the 
 velocity preserved by the water after it had acted upon the floats depends upon the relation of V and 
 v, and in order that V — v = 0, the wheel must have the same velocity as the current. In this case also 
 the whole expression vanishes, or the power realized is nothing ; for then the whole force of the water 
 will be absorbed by its own velocity, and could only turn the wheel at an equal velocity when the 
 burden (including its own weight and passive resistances) of the w 7 heel is nothing. The formula is, 
 therefore, consistent with itself in the most extreme cases, and may be accepted as a fair representation 
 of the effect realized in all intermediate conditions. 
 
 There are other modes of establishing the rule, which it may be at least satisfactory to state, more 
 especially as it will be necessary to resort to them in a subsequent part of the inquiry. According to 
 a well-known notation in dynamics, the weight of a body divided by gravity g is called tbe mass ; and 
 the mass multiplied into the velocity in feet per second is denominated the quantity of movement, or 
 pressure of the body. 
 
 Adopting this notation, and denoting the weight of fluid which flows in a second by w, and its velocity 
 by V ; then the mass will be represented by — and tbe quantity of movement or pressure by — V. But 
 the floats of the wheel are assumed to recede from the impulse with a velocity of v feet per second ; 
 
 the pressure exercised upon them will therefore be reduced to - (V — v ) ; but the space passed through 
 by the wheel, impelled by this pressure, is v feet per second ; consequently the dynamical force (the 
 product of the pressure and velocity) will be — (V — v) v per second; or taking W = 60 w, it will be 
 
 W 3 
 
 — (V — v) v per minute. But as before observed, 
 
 9 
 
 W,„ , , Tr \ V 2 v (V— u) 2 ) 
 
 ( V — v)v = VV < 
 
 9 1*9 2 g 
 
 ’■9 2 g S 
 
 as may be found by reduction of this last expression. 
 
 From the principle formerly adverted to of the relation of the velocity possessed by a falling body, 
 to the height through which it must have fallen to acquire that velocity, it follows that the weight 
 being w pounds, and the velocity Y feet per second, there must be accumulated in the body a number 
 
 . . . V 2 
 
 of units of dynamical force represented by the former w — as before shown. After it has passed from 
 
 the velocity V to the less velocity U, there will be accumulated in it the number of units of force rep- 
 U 2 
 
 resented by w — — There will therefore have been taken from its dynamic force a number of units 
 2 9‘ 
 
 V 2 U 2 W 
 
 represented by w w — = — (V 2 — U) 2 . Now this must be equally true of a current of water 
 
 "9 ^ 9 " g 
 
 or of any other body ; consequently, if the velocity with which it meets the floats of the wheel be V, 
 and it escape with the reduced velocity U, the force lost by its action will be expressed by 
 
 W 
 
 __ (V 2 -U 2 ). 
 
 But this force has been lost by impulse upon the floats, and ought, theoretically, to have been en- 
 tirely communicated to them. On this assumption, if v denote the velocity of the wheel in feet per 
 
 W 
 
 second, and p the pressure overcome, then will p v = — — (V 2 — U 2 ). 
 
 But on the assumption that the water meets the floats of the wheel without shock, it will leave them 
 with a velocity, as before shown, of (V — v — U) feet per second ; consequently, putting for U 2 its 
 equivalent (V — v)' 1 and reduce our formula by performing the operations indicated, we find 
 
 pv= rg (v ' 2 
 
 -(Y- 
 
 2 D 
 
 W 
 
 ■ vf) = -- (V — v) v 
 
 which is the same expression which resulted from the preceding modes of investigating the question 
 In the case of purely undershot and other impulsive wheels, we may therefore assume the effect, 
 
 E = Wi |^( V— '’) ^ 
 
 in which, as before, m is coefficient determined by experiment, and W the weight of water in pounds 
 per minute ; and V and v are respectively the velocities of the water, and of the periphery of the wheel 
 in feet per second. 
 
 This formula was first given in all its precision and generality by Borda, in his memoir on water- 
 wheels, presented to the French Academy in 1767. Having called z the velocity with which the wal“- 
 
846 
 
 WATER-WHEELS. 
 
 abandons the machine, and — to 2 the sum of the losses of vis-viva sustained by the fluid, he gives, as a gen- 
 eral corollary to the principles demonstrated in his memoir, the relation, 
 
 P v = 'P(h—~ 
 
 ‘ V 2y2u/ 
 
 which is exactly the same as that above established, p being the pressure overcome by the wheel, v its 
 velocity in feet per second ; P the total pressure due to the weight of water, and h the head real or 
 Active ; u — V ■ — v the difference of velocity of the current and of the periphery of the wheel. Deceived 
 by his formula, he, however, remarks that in the case of the greatest effect u = 0 and z = 0 ; whence 
 p v = P h, which in plain language signifies that the wheel being at rest, the whole power of the stream 
 is realized. This is evidently absurd ; but the absurdity is in the interpretation, not in the formula. 
 When u and z are respectively zero, no power is realized, but the floats of the wheel entirely obstruct 
 the passage of the water, and sustain the whole pressure P h. But pressure without motion is not 
 power. The error has, however, been reiterated until it has assumed the position of an established prin- 
 ciple. Thus every writer since Carnot has laid it down, as the basis of the theory of hydraulic ma- 
 chines, “ that in order that the machine may produce the greatest possible effect, it is necessary that the 
 water shall arrive and act upon it without shock, and quit it without velocity.” That the maximum 
 effect be obtained, it is admitted that there must be no percussive action ; the fluid must lose its velocity 
 by insensible degrees ; but to suppose that it shall quit the wheel without velocity, is to suppose that 
 the wheel itself has motion equal to that of the stream, and consequently produces no mechanical effect. 
 The doctrine is, however, true, if, instead of velocity, we read “ relative velocity.” In this case no water 
 will escape that has not given up a certain amount of its movement to the wheel, and it will clearly pos- 
 sess the least quantity of motion consistent with its action upon the floats, namely, an absolute velocity 
 equal to theirs. On this condition we shall have v — Y — v and therefore v — $ V, which implies that 
 the wheel ought to take half, and only half, the velocity of the current. 
 
 We shall hereafter And that this conclusion requires modiAcation ; but in the mean time it is suffi- 
 cient to intimate the mode of calculation, and to point out the theoretical conditions which form the 
 basis of inquiry. 
 
 It now only remains in this place to indicate the general principle of the reaction of water. Accord- 
 ing to Newton’s third law of motion, action and reaction are equal in amount and opposite in direction. 
 This proposition assumes the character of an axiom, when the mind is directed to the reciprocal action 
 of solids, since it is clear that any body acting upon another by pressure, for example, must itself ex- 
 perience a reaction equal and directly opposed to the action which it exercises. In the same manner, 
 whenever a force, as that of gravity, pressing upon a fluid, causes it to issue through an orifice formed 
 in the side of a containing vessel, a force equal and contrary to that with which the stream issues will, 
 in consequence, be expended upon the side of the vessel opposite to the oriflee of escape. To explain 
 this very briefly : when a part of the weight of a fluid is expended in producing motion in any direc- 
 tion, an equal pressure is necessarily deducted from its pressure in the opposite direction, for the gravi- 
 tation employed in generating velocity cannot at the same instant be causing pressure. Supposing an 
 oriflee to be made in the bottom of a vessel Ailed with water, a column of the fluid will descend 
 through it, and will expend during its descent a quantity of pressure equal to a column of twice the 
 depth of the fluid in the vessel, and having an area equal to the least section of the stream. For exam- 
 ple : suppose the vessel to be 16 feet deep, and to be kept constantly full, the velocity of the stream 
 will be 32 feet in a second ; and, therefore, a column of 32 feet of length will pass through the oriflee 
 in each second, with the whole velocity derivable from its weight acting for the time. It is therefore 
 clear that an equal amount of the pressure of the fluid in the vessel must be expended in producing 
 that velocity, and must of course be deducted from the weight of the whole fluid — that is, from the 
 entire pressure which it would otherwise exercise on the bottom of the vessel. Now, what is true with 
 respect to vertical descent, is equally true when the motion is in any other direction. When the orifice 
 is formed in the side of the vessel, the pressure upon that side will be diminished by as much as the 
 pressure employed in producing the motion ; and the effect of the diminution of the pressure in that 
 direction will be the same as if the vessel were subjected to an equal pressure of any other kind in an 
 opposite direction. And, moreover, the pressure being lateral, and therefore perpendicular to the only 
 direction in which a vertical force, like that of gravity, can itself act. it must be derived from reaction of 
 the opposite surface of the vessel upon the moving particles of the fluid, and may be assimilated to the 
 constant pressure of a spring interposed between the moving particles and the part of the vessel im- 
 mediately opposite to the orifice. In this position the spring must needs act in a direction exactly con- 
 trary to that of the movement impressed upon the fluid, and with an intensity exactly equal to the hy- 
 draulic pressure — that is, to the force due to the volume of water issuing by the orifice. Now, if .$ be 
 taken to denote the cross sectional area, in square feet, of the stream, and h the depth of the water above 
 the centre of the orifice, then the quantity of water discharged in a second will be s V 2g h cubic feet, 
 and the weight 62'5 s V 2g h. But the hydraulic pressure due to this volume of water will be 62 - 5 
 s X 2 h, which is the weight in pounds which would be necessary and sufficient to prevent the vessel 
 from receding in a direction opposite to that in which the water issues. To approach the actual condi- 
 tions : suppose a vertical cylinder with two hollow tubes inserted near its base, and projecting laterally 
 at right angles to its axis ; that these tubes are closed at their outward extremities, and communicate 
 freely with the interior of the cylinder ; that an orifice is pierced near the extremity of each on opposite 
 sides of their common axis, and in a plane passing through that axis perpendicular to the axis of the 
 cylinder. If this apparatus be placed on a vertical axis, round which it is free to revolve, it will consti- 
 tute that variety of hydraulic machine known as Barker’s Mill, and may be considered a type of those 
 machines which derive their power from the reaction of fluids. Water being let in to fill the vertical 
 
WATER-WHEELS. 
 
 847 
 
 cylinder, it will flow into the horizontal tubes, and issue by the lateral orifices , but in thus finding vent 
 into the atmosphere through the (contrary) sides of the tubes, these will be made to recede in a direc- 
 tion opposite to that in which the water flows out, and thereby produce a circular motion of the appa- 
 ratus round the axis by which it is confined. 
 
 To arrive at a general notion of the power developed by the revolution of the machine, let us denote 
 the depth of the cylinder above the level of the orifices by H, and the sum of the cross-sectional areas 
 of the jets by S ; if the cylinder be kept constantly full of water to the depth H, then the weight which 
 must be applied in an opposite direction to that in which the machine tends to revolve, and at the same 
 distance from the axis of revolution as the centres of the orifices, to prevent the machine from getting 
 into motion, will be 624 S X 2H lbs., this being the hydraulic pressure due to the quantity of water 
 S s/iyti. cubic feet discharged each second. Otherwise expressed, the weight necessary and sufficient 
 to balance the hydraulic pressure, and thereby to prevent the machine from revolving, is that of a col- 
 umn of water equal in length to twice the head, and having an area of base equal to the sum of the 
 cross-sectional areas of the two jets. This is found to agree with experiment, and it may be determined 
 from a priori reasoning. In every body falling freely, the velocity acquired in a given unit of time is 
 such as would carry it through double the space which it has fallen during the next equal unit of time, 
 supposing gravity to cease to act upon it. There must, therefore, have issued by each of the orifices of 
 the machine, a column of water equal to double the height of the surface above the orifices, that is, 2 II, 
 and the weight of such column is manifestly 624 S X 2H. 
 
 This will then be the condition of the machine held in a state of rest by a weight balancing the hy- 
 draulic pressure of the water discharged by its orifices. But when it is allowed to get into motion 
 another important condition is superadded. Centrifugal force is brought into action, and increases the 
 pressure of the water at the orifices, and thereby augments the quantity discharged in a given time, 
 and also the intensity of the reaction, exactly as if the head-pressure or depth of the cylinder were cor- 
 respondingly increased. 
 
 A common expression for the centrifugal force of a body revolving in a circle at a distance x from the 
 w . . v 
 
 centre of motion is — J 2 x, in which w is the angular velocity at the distance x, and is = - when v ex 
 
 presses the absolute velocity in feet per second, at the distance x. Now, if the mass — of the body ad- 
 vance in the direction of the radius outwards, through the element of space d x, in an instant of time, the 
 
 . . , V) 
 
 quantity of action (vis viva) created by the centrifugal force will be -uLIi. But this, being true of 
 
 n solid body, will be equally true of the molecules of water in the arms of the machine. If, therefore, 
 these arms commence at a distance r and extend to a distance R (the centres of the orifices) from 
 the centre of rotation, we shall have, by integrating for the space between r and R. the length of 
 each arm. 
 
 R 
 
 / 
 
 u 2 .rd.r = 4-u, 2 (R 2 — r 2 ). 
 r 9 9 
 
 And since u> = — , if we take the quantity of water vi = 1, we have, as the pressure at the orifices due 
 to the velocity of rotation, 
 
 w v 1 / r 2 \ 
 
 4 - u *( R *_ f .* )= (i__y 
 
 9 2.0 \ R-/ 
 
 If, therefore, we add this 
 orifices of the machine, 
 
 to the initial head-pressure H, we shall have as the whole pressure at the 
 
 II 
 
 Now, under this pressure, the expenditure of water will be increased as 
 
 v'2y II to v/2y II -f v* ^1 — -^Y that is, 
 as 1 to ^l+4i(l-^)’ 
 
 putting V for the velocity due to the initial head H; and supposing the permanent head II to have 
 
 been increased by the quantity ~ ^ l _ L ^ by directly increasing the depth of the cylinder, it is 
 
 plain, from what has before been stated respecting the force of reaction, that the weight which would 
 just be sufficient to keep the machine from getting into motion, would be 
 
 «2-5SX2|h + £(,_^)|u* 
 
 This, then, is the whole pressure of reaction due to the increased head II + — ( 1 ■ but the le- 
 
 '2 g \ R7 ’ 
 
 p J p V 
 
 action due to the Active part — p — is obtained in consequence of the rotatory motion of the 
 
848 
 
 WATER-WHEELS. 
 
 machine, with a velocity of v feet per second ; a portion, therefore, of the whole reaction due to the 
 quantity of water expended, must have been consumed in communicating that velocity to the volume 
 of water discharged in that second of time. The pressure, thereby withdrawn from that due to the 
 condition of rest will be expressed by the mass X into the velocity, that is, by 
 
 62'5S v /2 i/ H + » ! (l- j | i ) 
 
 9 XV ’ 
 
 and this pressure being subtracted from the pressure due to the whole force of reaction, there remains 
 the whole effective pressure, that is, the resistance or load which the machine can overcome at the given 
 velocity, v feet per second. The operation being performed, we obtain 
 
 62JS 
 9 
 
 But the weight of water discharged in a second is 
 
 
 624 5 
 
 
 therefore, 
 
 624 S = 
 
 If, then, we put for 624 S in the foregoing expression this equivalent, and reduce, we obtain the conve- 
 nient formula, 
 
 
 Now, this being the pressure acting upon the machine, and the velocity being v feet per second, the 
 power transmitted, supposing no loss, will be 
 
 
 and 
 
 putting V = v / 2 £rH + w s (l — 
 
 or 
 
 (V — v) v, 
 
 the formula takes the form 
 
 9 
 
 in which w = the weight of water discharged in a second ; V the velocity of the issuing jets, and v the 
 absolute velocity of the machine, in feet per second. The theoretical rule thus agrees with that estab- 
 lished for wheels which derive their efficiency from the impulse of the stream, thereby verifying the 
 doctrine that action and reaction are equal. There still remains, however, to determine the value of 
 the experimental coefficient m, with which this expression must likewise be affected to render it avail- 
 able in practice ; but this being different for differently constructed machines, we cannot pursue the 
 inquiry in this place. 
 
 The rule may be otherwise established thus : The whole laboring force, or mechanical efficiency of the 
 water, expended under a head-pressure of H + ^ 1 — — J feet, will be 
 
 But of this efficiency there is consumed in giving rotatory motion to the water, and thereby raising the 
 v 1 / r~ \ v' / r 2 \ 
 
 head-pressure — ^1 — — 2 ^, the quantity — v 1 ^1 — w Hch consequently falls to be deducted 
 from the entire efficiency of the fluid. 
 
 Again, the water leaves the machine with a certain amount of velocity remaining in it, namelv, 
 a velocity equal to the difference between that with which it issues from the orifices under the virtual 
 
 / r 2 \ 
 
 head H -f- — ^1 — — and the velocity of the machine measured on the tangent to the circle 
 through which the orifices revolve ; this difference of velocity will be expressed by 
 
 v' 2 s'H + u 2 (l — ^ 5 )— v, 
 
 and the quantity of laboring force due to it will be 
 
 2 9 
 
 j v / l 2yH+* 2 (l--L)_rj. 
 
WATER- WHEELS. 
 
 849 
 
 This likewise falls to be deducted from the laboring force due to the water expended under the head 
 II -f- — — W')’ * eav * n » efficiency communicated to the machine 
 
 
 
 which is the same formula as we obtained by the preceding investigation, and which, it may be well to 
 ooserve, would correctly represent the action of the machine, were it not that it is liable to modification 
 by certain incidental influences, which remain to be examined when we come to treat of the details of 
 construction, and other circumstances by which the efficiency of the machine is affected. 
 
 We now pass to the examination of the different varieties of wheels before indicated, and shall take 
 them nearly in the order given, but under a somewhat more convenient division 
 
 Bucket-wheels . — Under this head we include those nominal varieties of vertical wheels — overshot and 
 breast — which are provided with buckets upon their peripheries for the reception of the water, and 
 which, therefore, derive their efficiency chiefly from the weight of the fluid received into the buckets. 
 This form of wheel, at whatever point the water may be received upon its circumference, is the most 
 obvious in its action. No hydraulic machine could be more simple : a given weight descends from a 
 given height ; a known power is thus expended, to which the work performed ought to bear an assign- 
 able relation. 
 
 The older bucket-wheels which we encounter are constructed of wood ; but that material, once of 
 almost universal use in constructive mechanics, is fast giving place to iron, and in a few years hence we 
 may expect that a wooden water-wheel will be as rare, and as much an object of antiquarian interest 
 to those who take pleasure in reviewing the progress of the industrial arts, as wooden geering has 
 already become. Many of those wheels still continue to exhibit in their constructive details a very su- 
 perior style of workmanship, and an attention to durability which, in several instances within the knowl- 
 edge of the writer, the lapse of a century has hardly conquered. The best specimens, no doubt, only 
 remain of the truly old construction, while those of an inferior grade have disappeared and been replaced 
 by wheels of modern construction, in which iron, if not the sole material, holds at Jeast a prominent 
 place. 
 
 3774. 
 
 Another peculiarity, not indeed uncommon in wheels of recent construction, although generally aban 
 doued by millwrights who make pretensions to a superior knowledge of the principles which ought to 
 govern the transmission of hydraulic power, unless the conditions be dictated by extraneous circumstan- 
 ces, consists in passing the water over the summit of the wheel into the buckets in the manner 
 'represented in Fig. 3174. This arrangement constitutes literally an overshot-wlieel; but while we 
 have preserved the name, it is no longer deemed necessary to apply it literally. In the present accep- 
 tation of the term, nothing more is implied than that the water is received into the buckets near the 
 summit of the wheel ; and, in ordinary practice, those wheels reckoned as overshot, by strict definition 
 Vol. II.— 54 
 
850 
 
 WATER-WHEELS. 
 
 some under the designation of high-breast -wheels. One of the finest specimens of this construction yet 
 erected is that represented in Figs. 3778 and 3779, in which the height of the fall bears to the diameter 
 of the wheel the relation of 9 to 10. In the purely overshot-wheel this relation, as we shall immedi- 
 ately have, occasion to show, is very nearly inverted. 
 
 3778. 3779. 
 
 In the construction of wheels of this class, the technical points which remain to be considered, after de- 
 termining the diameter and breadth of the wheel from the height of fall and quantity of water furnished 
 by the stream, are the axle and its journals, the arms and their connections, the shrouding, sole, and 
 buckets. 
 
 The subject of the axle and journals has already been very fully noticed w 7 hen treating of shafts in 
 the article on Geering, (which see ;) but it may be here added that in iron wheels of great weight and 
 breadth, in which the axle is consequently of corresponding diameter and length, and especially when 
 the wheel is to be transported to a considerable distance from the work at which it is constructed, it is 
 not uncommon to make the axle of two, or even of three parts. When the axle is formed in this man- 
 ner, the parts are fitted together by turning, and are secured by bolts in strong flanges cast upon the 
 contiguous extremities. Fig. 3775 will convey an idea of this arrangement in its best and most endur- 
 ing form — that in which it is least liable to objection. But no force of ingenuity can render it safe ; 
 the constantly changing position of the weight ultimately, and sometimes, indeed, very speedily, acts 
 injuriously on the bolts, thereby relaxing the joint, which it is all but impossible to refit with any pros- 
 pect of durability. This result is greatly delayed by boring the bolt-holes in the flanges, and turning 
 the bolts exactly to fill them. In fitting the parts together permanently the bolts ought to be inserted 
 hot and have the nuts fully screwed up before they have contracted to their normal length. As a fur- 
 ther precaution, the bearing surfaces may be rusted together by washing them immediately before 
 they are put together with a dilute solution of sal-ammoniac. 
 
 In wheels composed entirely of wood, the eight principal arms are commonly disposed in parallel 
 pairs, crossing each upon the axle to which they have no positive attachment. The arms at the points 
 •»f crossing are bolted together in sets of four, and the two frames thus formed are set apart upon the 
 axle at a distance from each other, determined by the intended breadth of the wheel, and are bound to- 
 gether by tie-rods, and not unfrequently by diagonal struts when the breadth of the wheel is cousidera 
 He, yet not sufficient to require the introduction of an intermediate set of arms and partition shrouding 
 
WATER-WHEELS. 
 
 851 
 
 The framing is further secured in its place upon the axle by wedging. The material used for this pur- 
 pose is commonly oak, which, on being driven as firmly as the nature of the material will admit, is in- 
 terspersed with thin iz’on wedges to give further compactness and solidity to the joint, and to prevent 
 the packing from relaxing. These crosses of four arms each thus fixed in position sustain the two late- 
 ral shroudings between which the buckets of the wheels are inserted. They are termed the master, 
 main, or principal arms ; and in wheels of very small diameter — 14 feet and under — there are no other 
 employed. But when the diameter of the wheel exceeds the limit at which the arcs of the shrouding 
 would be safely supported at that minimum number of points, a series of auxiliary arms are introduced, 
 in sets of four, on each side of the wheel. These secondary arms do not cross each other at the axle 
 as the principal arms do, but are simply made to abut against its faces, where they are secured by 
 filling blocks, laid in in different ways, according to the number of auxiliaries introduced. They are 
 further secured by bolts to the master-arms, which they are always made to cross in the manner rep- 
 resented. 
 
 When the wood is sound, and no particular circumstances intervene to increase the strain upon the 
 wheel, the strength of the arms may be computed by the ordinary rules applicable to the kind of wood 
 employed in the construction. In a very elegant specimen of 48 feet diameter the arms at the base are 
 8 inches square, and taper to 6 inches at the extremities. 
 
 In wooden wheels of more modern construction, instead of the arms being framed together upon the 
 axle in the manner just described, their bases are inserted, and generally fixed by wedges in iron cen- 
 tres previously fitted upon the axle. This is a much more elegant and substantial arrangement, and is 
 applicable to all the varieties of vertical wheels, and to all diameters ; but it does not always happen 
 that the mode of fitting is the best adapted for durability or convenience of repair. Very commonly 
 the centres are solid castings, with recesses in the periphery corresponding in number and size to the 
 arms which they are intended to receive ; and when the arms are formed of malleable-iron bars, this 
 arrangement is all that could be desired. But for wooden arms, the recesses ought to be considerably 
 more in breadth than the butts to be inserted into them ; and these ought to be fixed, not with iron, but 
 by wooden keys, and without the aid of bolts. If the outside cover be cast separately as a loose ring, 
 and bolted upon the centre after the butts of the arms are fitted, it will allow of the recesses to be 
 formed widest at bottom, and the butts to be made dovetail-shaped, and secured by parallel keys a a, 
 in the manner represented by the arms A A, in Fig. 3776. These recesses, when the work is of a 
 superior character, would be planed on all , the bearing surfaces, and the cover might be fitted by 
 turning. 
 
 This mode of fitting is equally suitable for cast-iron arms, except that the keys are in that case ren- 
 dered unnecessary by the butts being made to fill the recesses, and are carefully fitted- by planing. 
 They are also secured by bolts, and it is not often that any cover is employed. 
 
 When the wheel is of small diameter the centres and arms are sometimes, and advantageously, formed 
 of one casting. In this case no fitting is required ; and although the moulder’s labor is greater, there 
 is an ultimate economy, when the diameter does not much exceed 12 feet, which more than balances 
 the excess of foundry cost. In one small example we have observed the principle extended to the shroud 
 ing ; each side of the wheel consisted of a single casting, and the two were simply bound together by 
 a few tie-rods, and the sheet-iron plates, of which the buckets were composed. 
 
 The shrouding is formed of two annular plates, which, in wooden wheels, are composed of plank, of 
 3-J inches to 7 inches thick, shaped and jointed together similarly to the felloes of a carriage-wheel. 
 Instead, however, of the joints being formed by simply abutting the extremity of one piece upon that 
 adjacent, the extremities are checked to half their thickness upon opposite sides, and overlapped. 
 Sometimes also the joints are made by scarfing, when not opposite to the arms, and strengthened by 
 plates of iron laid into recesses flush with the general surface. The other joints which receive the ex- 
 tremities of the arms are half-checked on the exterior surface, and are connected by the palms, which 
 are usually counter-checked on the inner face, to fall flush into the recesses prepared for them in the 
 ends of the pieces which they are intended to connect. With the old millwrights it was not uncommon 
 
 to form the joints of the better class of wheels by mortise-and-tennon, and sometimes by joggles a 
 
 method which seems to us equally efficient and less expensive. 
 
 In the older wooden wheels the shrouding is usually of a greater depth than is consistent with mod- 
 ern practice. At present we meet with few examples in which the shrouding is more than 12 to 15 
 inches deep, whereas a depth of 20 inches was formerly not uncommon. This is a subject, however, 
 which will require to be considered subsequently, as also the width of the wheel or distance between 
 the shrouds. 
 
 The width of the wheel determines the length of the buckets. These extend between the shrouds, 
 except in very broad wheels, in which an intermediate or partition shrouding is sometimes introduced 
 to give support to the buckets at the middle of their length. This is usually resorted to in wooden 
 wheels when the breadth exceeds 8 feet, but it is not uncommon to find iron wheels of double that 
 breadth without any partition shrouding. In this class of wheels it is, indeed, an excepted case in which 
 we find this arrangement adopted in the entirety exhibited by the older specimens. In these the par- 
 tition shrouding was, in all respects, a duplicate of the lateral shrouds, and was like them attached upon 
 arms radiating from an independent centre, placed intermediate to the two others upon the axle of the 
 wheel. Besides giving additional rigidity to the struction, it served to carry the medial extremities of 
 the buckets, which being formed of plank, did not admit of that ready mode of staying, so convenient 
 with sheet-iron buckets, as exemplified in Fig. 3778 and elsewhere. 
 
 The shrouds being properly adjusted and fixed in relation to the axis of motion, a circular runner ot 
 plank having a transverse section of 3 X 3 inches, is attached by wood-screws to the interior face of 
 each of the shroud-plates, and upon this the ends of the sole-planks are supported. We speak of the 
 best form of construction ; but more frequently the sole-planks are simply fitted and fixed upon the in- 
 terior circumference of the shrouding ; and this arrangement has its advantage in the facility which it 
 
852 
 
 WATER-WHEELS. 
 
 allows for the repair of the sole, a9 the planks may be taken off without disturbing the buckets in then 
 vicinity. When the sole is completed the wheel has the appearance of a large drum with radial flanges, 
 between which the buckets are to be fixed. The extremities of the planks of which the buckets are 
 formed are commonly received into mortises cut in the contiguous faces of the shroud-plates ; or into 
 grooves formed by narrow runners of wood nailed upon the plates. A still better mode of fitting is to 
 sprig the buckets in their places, or to mark off their form and positions upon the inner surfaces of the 
 shrouding, and fill in the spaces between them by plates of board cut to the proper form. When the 
 first method is adopted it is necessary to insert the radial part DF of Fig. 3780, before fixing the sole- 
 planks ; but by forming grooves according to the latter methods, the sole may be completed previous 
 to any part of the bucketing being prepared. When the method of mortising is adopted it is, on the 
 contrary, more convenient to make the bucketing precede the application of the sole-planking. It is of 
 little moment which of these methods be adopted in practice, and the circumstances of the particular 
 case will invariably determine that which may be resorted to with most advantage ; but it is of the ut- 
 most importance that in the process of deeding the wheel be not thrown out of truth. To avoid this, 
 the operations ought to proceed from at least two points ; and if the wdieel be of large diameter it will 
 give a better chance of correctness to distribute the operations over the four quadrants of the wheel, 
 taking alternately that immediately opposite and contiguous as the next in succession to be operated 
 upon. 
 
 Each bucket consists usually of two plates placed at a determinate angle A D F, Fig. 3780 ; and some- 
 times of three, as in the form indicated at P M. The bucket is an essential part of the wheel, which ought 
 to be determined not by the rule-of-thumb practice admissible in some of the less important details, but from 
 a competent regard to the conditions involved. Upon their form depends, in a great measure, the effi- 
 ciency of the wheel as a hydraulic motor ; and although with wood the true conditions which lead to 
 the best effect can only be very distantly approximated, it may still be of advantage to indicate these 
 as nearly as the circumstances will admit. 
 
 Having determined the diameter of the wheel and the depth of the shrouding — the rules for which 
 will be hereafter adverted to at length — let portions of their circles A S and B Q be described from a 
 common centre, as O in Fig. 3780. Let the depth A B of the buckets be divided into three equal parts 
 and with a radius to C, making BC = | AC describe the arc C D E of the third circumference upon 
 which the centre of gravity of the water contained in the buckets will always be found, at least very nearly. 
 This radius, marked 0 r in Fig. 3774, is termed the dynamic radius of the wheel, and it is of importance 
 that it be correctly defined. The distance of one bucket from that succeeding it is measured upon this 
 last circumference, and may be taken generally at 12 to 134 inches. The common practice is to divide 
 the circumference into four equal parts, and in each quarter is inserted the same number of buckets, the 
 distance being made to vary slightly with the size of the wheel. But it also follows from this practice 
 that the number of buckets will not be exactly proportional to the diameter. An approximate rule is 
 to double the number expressing the diameter of the wheel in feet, and call that or the next higher 
 number divisible by 4, the number of buckets. 
 
 Thus the diameter being 12 feet, the number of buckets 24. 
 
 “ “ 17 “ “ “ 36. 
 
 “ “ 21 “ “ “ 44. 
 
 » « 05 « “ “ 50, 
 
 In greater diameters, the proportion increases thus : 
 
 Diameter, 28 feet Buckets, 60 
 
 “ 32 “ “ 72 
 
 “ 38 “ “ 84 
 
 We do not instance these as examples to be copied, but simply in illustration of a practice not yet quite 
 obliterated, of referring the mo3t vital conditions of the question to a haphazard empiricism, which pre- 
 tends to no better foundation than its affording an easy approximation. The proper elements from which 
 the capacity of the buckets ought to be determined are the quantity of water to be used and the angu- 
 lar velocity of the wheel, subjects which will be subsequently considered in relation to this and other 
 questions of equal importance. 
 
 The circumference described by the dynamical radius of the wheel being divided into equal parts, 
 C, D, E, &c., in number equal to the number of buckets which the wheel is intended to have, the radial 
 lines C B, D F, E G, <fec., will determine the direction and breadth of the starts of the buckets. Th e. flats 
 A D, H E, Ac., are determined by regard to the condition that the angle H E G, comprised between the 
 Btart and flat of the same bucket, ought to open as little as possible, in order that the bucket may re- 
 tain its water as long as possible ; but at the same time the angle must be sufficiently great that the 
 water shall have free admission through the space D 6, otherwise a portion of it would be thrown back 
 chiefly by the action of the air confined in the bucket — an evil now almost entirely remedied by the sys- 
 tem of ventilation introduced in the construction, but which in wooden wheels could only be effected very 
 
 Diameter, 40 feet Buckets, 22 
 
 “ 42 “ “ 96 
 
 “ 46 “ “ 108 
 
WATER-WHEELS. 
 
 853 
 
 imperfectly. In all cases it is essentially and obviously requisite that the space between the flats be 
 considerably greater than the thickness of the sheet of water which is thrown upon the wheel. It is 
 true, that by increasing the breadth of the stream, its thickness may be diminished at pleasure. Still 
 it is necessary to give to D b a minimum of 5 to 6 inches, to insure free ingress to the water in all posi- 
 tions of the bucket, while receiving its charge. This condition is attained by giving to the angle IT E G 
 a value of 110° to 118°, supposing the wheel to have a diameter not less than 15 feet. Under this ar- 
 rangement, the flat will have an inclination to the interior circumference — rather to a tangent drawn to 
 that circumference from the point of intersection with the exterior circumference — of about 31°, and not 
 more than 33°. This angle is indicated by the tangent in Fig. 3774. 
 
 Some millwrights have endeavored to lessen the evil experienced in the water being thrown out of 
 the buckets by increasing the breadth of the starts, as in the bucket LKI, in which I K = \ I P. And 
 as an approach to the more modern curved bucket, the form P M has been employed, in which the flat 
 is composed of two parts, P 0,0 N, joined together at an angle of about 150°. This form has an ad- 
 vantage in so far as it retains the water longer; but besides increasing the labor and difficulty of fitting 
 and repairing the buckets, it has the further effect of contracting the space through which the water is 
 received into the bucket, which, under the very imperfect system of ventilation practicable in wood 
 wheels, is an evil more than equivalent to the advantage secured Even the mode of fitting the two 
 plates of the bucket together by a bevel-joint, as at D, is considered by some millwrights as an unneces- 
 sary technical difficulty, which they avoid by fitting the start-board at an angle of 90° with the flat- 
 board. This practice has an advantage in point of simplicity of construction, and it does not seem liable 
 to any serious theoretical objection. But the difficulty complained of is more effectually removed by 
 the introduction of sheet-iron buckets, which is not now uncommon, even in wheels principally con- 
 structed of wood. The usual practice is to curve the plate into the form S Q, in which the start to tire 
 point R on the dynamical circumference approaches the circumference of the wheel at an angle of 90°, 
 and the extremity S meets that circumference at an angle of not more than 3°. In this mode of 
 bucketing, which, when introduced, was reckoned an improvement of much value, and which in modern 
 practice is the simplest that can be adopted, the buckets carry their water to the lowest point of the 
 revolution of the wheel ; but like that previously noticed, although it has an advantage in this respect, 
 it has been considered liable to the objection of affording a less ready admission to the water in filling. 
 In early practice, and, indeed, until very recently, the necessity of facilitating the escape of the air from 
 the buckets, when receiving their charge of water at the summit, was not understood. The importance 
 of making the buckets of a form to carry the water to the lowest point of the revolution of the wheel 
 was obvious ; but when this was accomplished, it was usually found that the wheel neither received nor 
 parted with the water freely. The late Professor Robinson seems to have been the first to give a full 
 explanation of these circumstances, and to have pointed out at least a partial remedy. In reference to 
 the first, he observes that “ the half-taught millwright attempts to retain the water a longer time in the 
 buckets, but finds that it gets into them with a difficulty for which he cannot account, and spills it about 
 even after they have ceased to receive any from the spout. This arises from the air, which must find 
 its way out to admit the water, but is obstructed by the entering water, and occasions a great splutter- 
 ing at the entry. This obstruction is vastly greater than one would imagine, for the water drags along 
 with it a great quantity of air, as is evident in the water-blast described by many authors.” 
 
 After observing that “ this evil may be entirely prevented by making the spout considerably nar- 
 rower than the wheel, and thereby leaving room at the two ends of the buckets for the escape of the 
 air,” he proceeds to consider the circumstances attending the emptying of the buckets. He observes, 
 “ There is another very serious obstruction to the motion of an overshot or bucketed wheel, especially 
 when it revolves in backwater. It is not much resisted by the water on account of the slowness of its 
 motion ; but it lifts a great deal of the water in the rising buckets. In some particular states of back- 
 water the descending bucket fills itself completely with water ; and in other cases it contains a very 
 considerable quantity of air of common density, while in some rare cases it contains both water and air 
 in a compressed state. In the first case, the rising bucket must come up filled with water, which it 
 cannot drop till its mouth gets out of the (tail) water. In the second case, part of the water goes out 
 before this ; but the air rarefies, and therefore there is still some water dragged or lifted up by the 
 wheel, but (which is as detrimental to its performance) the descending side is employed in condensing 
 the air ; and although this air aids the ascent of the rising side, it does not aid it so much as it impedes 
 the descending side, being (by the form of the bucket) nearer to the vertical line drawn through the 
 axis.” 
 
 Without acquiescing in the correctness of the objection and explanation contained in tins second case, 
 it is not difficult to perceive that if the bucket be quite air-tight, and of such a form a's to carry its charge 
 of water to the bottom of the circle of revolution, in the process of emptying itself against the atmos- 
 pheric pressure, and in a direction contrary to the direction of motion of the wheel, there will be a par- 
 tial vacuum formed in the bucket, and to that extent the effect of the wheel will be diminished. If 
 the bottom segment of the wheel be immersed in tail water, which is a very frequent circumstance, the 
 evil will be greatly increased, for then the bucket cannot relieve itself until its mouth has ascended 
 above the water-level ; and in consequence of the resistance offered to the descent of the water, the 
 bucket will have ascended considerably higher before i! is entirely relieved of its load. 
 
 The earliest remedy applied to the removal of these difficulties, and which has been continued to 
 some extent to the present time, was to bore holes in the starts of the buckets. As respects the admis- 
 sion of the water, this contrivance is of little value, as the escape of the contained air by the holes is 
 prevented by the presence of the water in the inferior bucket. But its success in promoting the easy 
 discharge of the water from the buckets soon became obvious, from the increased efficiency of the wheels 
 in which it was adopted. And besides its effect in facilitating the relief of the buckets by the admis- 
 sion of the air to replace the water discharged, it has the further advantage of preventing the trouble- 
 some and often dangerous effect of bucketing when the works are stopped, as the small quantity of 
 
854 
 
 WATER-WHEELS. 
 
 water escaping by the sluice and falling upon the wheel runs through the air-holes without accumula- 
 ting in the buckets of the wheel, and starting it into motion at intervals. 
 
 Mr. Fairbairn, of Manchester, to whom we owe the present improved system of ventilation, relates 
 in a paper submitted to the Institution of Civil Engineers, that about twenty years ago he constructed 
 a wheel for Mr. James Brown, of Linwood, near Paisley, “ which in floodwaters, when the wheel was 
 loaded, every bucket acted as a water-blast, and threw the water and spray to a height of six to eight 
 feet above the orifice at which it entered. This was complained of as a great evil; and in order to get 
 rid of the difficulty, incisions were made through the sole-plates, and small interior buckets were 
 attached to the inner sole-plates, as represented in Fig. 3781. ii'he air made its escape by the openings 
 
 3731. 
 
 a a a into the interior buckets bbb inside of tlie wheel during the time of filling ; and, when working 
 in backwater, it presented the same facilities for its emission before even a partial vacuum could be 
 formed in the ascending bucket when rising through the tailwater. The changes which this remarkable 
 alteration effected can scarcely be credited ; the wheel not only took and parted with the water with 
 perfect freedom, but an increase of power of nearly a fourth was obtained. The wheel is still in the 
 same state, and continues in all states of the water to perform an apparent and satisfactory amount of 
 duty.” 
 
 This was an important advance on the scheme of piercing the starts of the buckets ; and although in 
 this case applied to an iron wheel, it admits of easy application to wooden wheels, by making a species 
 of internal sole, and dividing it off into portions answering to the small buckets bbb, and of course 
 equal in number to the number of main buckets in the wheel. 
 
 The improvement effected upon Mr. Brown’s wheel subsequently induced 
 Mr. Fairbairn to extend the principle of ventilation ; and instead of waiting 
 to ascertain the action of the wheel when started, to apply it as a funda- 
 mental requisite to be provided for in the construction. The primary form 
 ui the contriS’ance, although very effective, is manifestly liable to objection 
 m respect of the additional workmanship which it required ; and besides, 
 if thoroughly carried into effect, would tend to weaken the sole-plate of 
 the wheel. To obviate these objections, Mr. Fairbairn introduced the 
 elegant arrangement depicted in Fig. 3782, by which the integrity of 
 the sole is preserved, and in which, with very little additional cost of con- 
 struction, the object is most effectually accomplished. The method consists 
 in forming the buckets — each consisting of a single plate — with independent 
 soles, which are applied parallel with the sole of the wheel, leaving between 
 the two contiguous surfaces a vacant space of about an inch, for the escape 
 of the air into the superior bucket during the process of filling, and which 
 will obviously serve to readmit the air to replace the water when the 
 bucket begins to empty itself towards the lowest point of its revolution 
 and begins to ascend. When it has attained this position, it ought mani- 
 festly to be entirely relieved of its burden ; but it has been already inti- 
 mated that, in certain conditions of backwater, this can be accomplished 
 only by some contrivance for admitting the pressure of the atmosphere 
 upon the water in the bucket immediately on its beginning to ascend. If 
 the atmosphere be then excluded, and the bucket he full of water, a cer- 
 tain amount of weight will be made to act adversely to the motion of the 
 wheel, and to that extent will diminish its efficiency. This takes place 
 more commonly with iron than with wooden buckets destitute of provision 
 for their ventilation, on account of the more contracted form of the inlet 
 passages produced by the curvature of the flats of the former. 
 
 On this subject Mr. Fairbairn remarks, that “ water-wheels constructed entirely of iron, and having 
 thin plates instead of wood for the buckets, give decreased facilities for the admission of the water, and 
 for the escape of the air contained in them. So great difficulty is experienced in effecting the discharge 
 of the air in a close bucket through the same orifice, and at the same time that the water is being ad- 
 mitted, as in some wheels almost entirely to prevent the entrance of the water ; and in cases where the 
 buckets are closely formed, the wheel is deprived of almost half its power by the reaction of the in- 
 closed air. This defect is most obvious in water-wheels having contracted openings — which may be 
 easily accounted for in every case where the water is discharged upon the wheel in a larger section 
 than the opening between the buckets. Under these circumstances the air is suddenly condensed, and 
 again reacting by its elastic force, throws back the water upon the orifice of the cistern, and thus allows 
 the buckets to pass without being more than half tilled.” 
 
 These remarks are intended to show the extent of the difficulties which have been removed by the 
 introduction of the ventilated bucket, and to induce the adoption of that system, which, we may remark. 
 
 3782. 
 
WATER-WHEELS. 
 
 85b 
 
 .a always applicable, and presents none of those constructive objections which are so often fatal to the 
 introduction of technical improvements in hydraulic machinery. This has, indeed, been acknowledged 
 by the almost universal adoption of the principle by those engineers capable of appreciating its advan- 
 tages ; but examples in which it has been disregarded — possibly through ignorance of its use — 
 have fallen under our notice very recently, and in more than one instance very fully illustrated the 
 danger of dealing with hydraulic power on mere empirical rules. 
 
 When the wheel is wholly constructed of iron, the buckets are usually supported at their extremities 
 on narrow flanges, cast of the intended form upon the inside faces of the shrouding, and secured by 
 small bolts, (usually half inch in diameter,) for which the holes are cast in the flanges, and bored in the 
 bucket-plates. They are further supported upon each other by intermediate stays, cast witli palms ni 
 opposite curvature at their extremities, to meet the interior and exterior surfaces of the buckets which 
 they are intended to connect. The details are fully illustrated in Figs. 3783 to 3795. 
 
 3783 . 
 
 3790 . 3 ? 91 . 
 
 It is, however, to be remarked that, except in the undershot-wheel of M. Poncelet, no attempt has 
 hitherto been made to give the buckets a definite form with reference to the action of the water upon 
 them on its admission ; and possibly under the system now generally adopted, of introducing it below 
 the summit, and under as small a head-pressure as can be obtained, consistently with the volume to be 
 used, it is of little importance to bring that element into the calculation. It may, however, be remarked 
 that, in strictness, when the water is allowed to fall simply over the lip of the bucket, the curve ought 
 
 3795 . 
 
 to be that of quickest descent ; and in no case ought it to descend from so great a height that its reac- 
 tion upon the under side of the succeeding bucket shall be sensibly felt. This appears to be well illus- 
 trated by the well-known experiments of Mr. Smeaton, to which we shall hereafter have occasion more 
 particularly to advert. His overshot model was 24 inches in diameter : and when the whole descent, of 
 
356 
 
 WATER-WHEELS. 
 
 the water was 27 inches, the maximum effect of the wheel was 76 per cent, of the power of the water 
 but when increased to 35 inches, the ratio fell to 52. In other words, the head being increased in the 
 ratio of 7 to 9, the increase of effect is only in the ratio of 81 to 84, and, consequently, the increase o: 
 effect is not 1-7 th of the increase of perpendicular height. From this he concludes, and correctly, as 
 respects purely overshot-wheels, “ that the higher the wheel is in proportion to the whole descent, the 
 greater will be the whole effect.” But the explanation which he offers is founded entirely on the opinion 
 “ that the effect of the same quantity of water, descending through the same perpendicular height, is 
 double when acting by its gravity upon an overshot-wheel, to what the same produces when acting ly 
 its impulse.” It is unnecessary, in the mean time, to examine this proposition, as it is sufficient for our 
 present purpose to intimate that a high velocity of the current entering the buckets is attended with a 
 lass of effect, and that at least a portion of that loss seems to us to result from the reaction of the 
 water against the sole of the bucket into which it is received, and against the bottom of the next suc- 
 ceeding bucket; and it is obvious that any impulsive force expended on these surfaces must propor- 
 tionally resist the motion of the wheel in the contrary direction. 
 
 As respects the mode of supplying the water to the overshot-wheel, the arrangement is sometimes 
 made to differ slightly, according as the level of the water in the reservoir or dam is nearly constant, 
 or varies between wide limits. In the first case, especially if the dam be close at hand and the duty 
 of the wheel nearly constant, the channel is simply formed of the proper width to bring forward the 
 maximum quantity which is intended to be employed upon the wheel ; and a sluice is placed at the 
 origin of the channel in the dam-breast to regulate the quantity drawn off for immediate use. From 
 this sluice, the channel — often formed of wooden troues — follows the most direct line over the summit 
 of the wheel, and is terminated by a spout inclined at an angle sufficient to throw tile water perpen- 
 dicularly upon the start of the second or third bucket counted from the summit. The apron or sole of 
 this spout is usually from 18 to 24 inches long, and declines from the bottom level of the channel at an 
 angle of 12 to 18 degrees, forming an incline plane on which the water attains the required velocity 
 before entering the buckets, and which ought to be at least equal to that of the circumference of the 
 wheel ; otherwise it is struck, and some portion of it thrown off by the flat-boards of the buckets as 
 they successively come into position with the current. 
 
 When the dam is at some considerable distance, rendering it inconvenient to have recourse to the 
 sluice there situated, on every occasion that it may be necessary to modify the power of the wheel, a 
 second sluice or shuttle is placed contiguous to the spout, and which, in the common class of wheels, is 
 usually set by hand at the required height, often directly, but sometimes a simple contrivance, consist- 
 ing of a weighted lever, intervenes, by which the shuttle can be adjusted by a cord brought inside of 
 the building. In the higher class of wheels, and especially when great steadiness of motion is required, 
 the shuttle is worked by a self-acting apparatus — shown in its most complete form in Figs. 3796 to 
 i-'SOS, with all the improvements and appliances of modern mechanism, as applied to the large wheel 
 m Greenock. 
 
 3793. 3797. 
 
 When the course is of considerable length, and the level of the water in the reservoir or dam is sub- 
 let to sudden variations, it is of advantage to adopt a slight modification of the spout by which the 
 water is thrown upon the wheel. If the sluice in the dam-breast be set to furnish the proper supply ol 
 water under a given head, and the level be increased, it will, of course, discharge a greater quantity 
 than is required, and thereby produce an increased head-pressure upon the shuttle. This may be low- 
 ered to diminish the quantity thrown upon the wheel ; but, in consequence of the bead-pressure accu- 
 
WATER-WHEELS. 
 
 857 
 
 mulated in the course, the velocity of efflux -would be increased often to such an extent as, -without 
 precaution, to throw the water entirely over the buckets. To prevent this, and, at the same time, to take 
 advantage of the increased impulse of the water, the spout is provided with a cover inclined to the axis 
 of the orifice, and connected, water-tight, with the back-plate of the shuttle. The spout has thus the 
 outline of a truncated pyramid, of which the faces converge towards the extremity at an angle of 6 to 
 V degrees with the axis, which is directed towards the superior surface of the start of the bucket im- 
 mediately in advance of it. The direction of the current upon the wheel is thus preserved under any 
 variations of head-pressure upon the shuttle ; and the impulse being directed as nearly as possible in 
 the line of motion of the point impelled, its value becomes an increment to the force of gravity of the 
 water, and, to some extent, economizes a power which would otherwise act injuriously in projecting the 
 water beyond the proper range. The horizontal dimension of the orifice, under this arrangement, and 
 especially when the system of ventilation is incomplete, ought to be a little less than that of the buckets, 
 and the height perpendicular to the axis ought not, in general, to be more than four inches, and it is 
 almost always better to be less. 
 
 This form of spout is represented in Fig. 3774. It has not been in very general use in this country, 
 although examples are still met with ; but it is still very commonly employed in Europe, espe- 
 cially in France, where it bears the significant name of “ duck's-bill.” In some cases, also, the spout is 
 attached to the feed-box or small reservoir formed over the wheel in some works, where the water is 
 brought forward from the main dam by a large pipe or covered conduit passing along the surface of 
 some intervening ground situated on a lower level than the summit of the wheel, and sometimes entirely 
 under ground, when it is necessary to keep the surface free of interruption for any particular reason, as 
 the crossing of a road and the like. In this arrangement, there is always a certain amount of loss of 
 head incurred by the passage of the water through the conduit, which must be taken into account in the 
 construction of the wheel. The effect of this diminution of head-pressure is to prevent the water from 
 rising to the same level in the feed-box as in the reservoir, by diminishing the force of the current ; and 
 this loss, which is also a loss of fall upon the wheel, and consequently a loss of moving force, without 
 any compensating advantage, except the convenience afforded under particular circumstances, must be 
 deducted from the height of the fall in determining the diameter of the wheel. 
 
 The natural situation for the opening to the culvert for carrying away the tail-water is on the side 
 opposite to that at which the water is received by the wheel ; for, in that case, should the lower arc of 
 the wheel dip, which it almost invariably does, from the desire entertained by the millwright to econo- 
 mize the fall as much as possible, the run of the water will impede it less than if its motion were op- 
 posed to the motion of the wheel. When the wheel is kept entirely above the level of the tail-water, 
 this arrangement may, of course, be reversed. It is then immaterial at what point the culvert opens 
 into the wheel-pit, except that the water will rise higher when the direction of its motion is changed 
 from that impressed upon it by the motion of the wheel, and consequently a greater amount of tail- 
 clearance must be allowed when the escape is retarded by a change of movement. This is, therefore, 
 always avoided as much as possible ; but in situations where the lead of the water is determined by 
 circumstances of locality, and the direction of the motion of the wheel by circumstances of convenience, 
 we commonly find that when these conditions conspire to render the common arrangement inapplicable 
 consistently with economy, that, instead of the water being led over the summit of the wheel, it is thrown 
 upon that side to which the current approaches, the spout of the shuttle being deflected sufficiently 
 backwards to reverse the motion of the current, and direct it upon the circumference at some distance be- 
 low the summit. It is easy to perceive that under this arrangement, which at first was resorted to 
 rather as an artifice to avoid an inconvenience, very severely felt in cases where the direction of the 
 waste-water culvert was fixed by local circumstances, and in which the wheel-pit was liable to be flooded 
 with backwater, allows of the wheel being made of any desired diameter even greater than tire height 
 of the fall. It also requires less of the head to be sacrificed between the shuttle and the point of the 
 wheel at which the water is received, and is, therefore, more economical than the primary arrangement 
 from which it was considered a deviation merely allowable in obedience to the local conditions of the 
 particular case. Its advantages, however, soon began to be perceived, especially in low falls, and exam- 
 
858 
 
 WATER- WHEELS. 
 
 pies of its application speedily became numerous. This was favored by the theoretical notion, that a 
 wheel of large diameter is, in all cases, the most economical ; and. as already observed, this arrange- 
 ment gives free scope to the millwright to adopt any diameter of wheel he may think fit. The system 
 has now become general, and constitutes one of the main characteristic features of the modern bucketed 
 wheel. It has, besides, removed the distinction between overshot and breast wheels, which was formerly 
 significant. The term overshot is, indeed, not now applicable to any of our larger modern examples, 
 except by a forced interpretation of the term, and instead we ought, in strictness, to employ the term 
 high-breast, as better expressing the actual conditions. We have still, indeed, some wheels of a minor 
 class scattered over the country, and employed chiefly for agricultural purposes, which belong to the 
 primitive order ; but they are only retained in situations where the power is superabundant, and where 
 it is, therefore, not necessary to look narrowly into the economy of its employment. 
 
 3804 . 
 
 In the higher class of wheels constructed according to this principle, and which were originally de- 
 nominated breech-wheels, the shuttle consists of an accurately fitted sluice, usually commanded by an 
 adjusting apparatus bearing the name of governor, which regulates the supply of water admitted upon 
 the wheel to the power required. The technical details and mode of action of this apparatus are fully 
 shown and described, in reference to the large wheel erected at Greenock for the Shaws Water Spin- 
 ning Co., and need not be here recapitulated ; but it may be well to observe that a fault is often com- 
 mitted in making the governor not only bring the sluice-geering into action, but to hold it in action un- 
 til the motion of the wheel has been sufficiently increased or diminished by the elevation or depression 
 of the sluice-plate. This is done for economy ; and it is admitted that the apparatus is thus greatly 
 simplified in its constructive details. But as all the pressure of throwing the geering out of action must 
 be overcome by the centrifugal force of the pendulum balls, these must, therefore, of necessity be of 
 great weight, and consequently less susceptible of being affected by slight variations of motion, on ac- 
 count of their greater inertia. But the far greater evil consists in the geering being kept in action until 
 the movement has been so far altered that the balls have acquired sufficient power to overcome the fric- 
 tion due to the pressure of the geering, and disengage itself ; and which cannot possibly happen until 
 the speed has been increased or diminished beyond the point required. To correct this, the governor 
 immediately falls into action to produce the contrary effect, which again is overdone, and must again be 
 corrected. From this cause, the movement of the wheel is never steady, but continually oscillates be- 
 tween two extremes, and the governing apparatus, though, in the first instance, less expensive, is 
 speedily worn out, being constantly in action, and is never satisfactory. The principle to be kept in 
 view is, to allow the pendulum balls to adjust themselves with perfect freedom to the velocity of the 
 wheel, by giving them no other duty to perform ; and, by a cam, obeying the motion of the balls, and 
 shifting its position in obedience to theirs, to throw the geering into action in the manner done in the 
 example above referred to. 
 
 When the height of the fall is considerably less than the diameter of the wheel, we then apply the 
 
WATER-WHEELS. 
 
 85S 
 
 term breast as expressing the relation. The -wheel depicted in Figs. 3804 and 3805 comes under this 
 general denomination ; and to denote that the water is received above the line passing horizontally 
 through the axis, it takes the name of high-brcast. These terms, however, are manifestly only relative ; 
 for if the wheel had been made of somewhat larger diameter, the water would have been thrown upon 
 a lower point of the circumference, and changed the character of the wheel to that of low-breast. These 
 terms, therefore, convey no other positive intimation respecting the size of the wheel than that its axis 
 is below, above, or in the plane of the water level. It, however, usually suggests that the fall is low, 
 and, consequently, that every precaution is taken to render it, as much as possible, available upon the 
 wheel.. For this purpose an arc is usually constructed of the same radius as that of the wheel, to con 
 
 fine tlie water, and prevent it from being spilt from the buckets before it has arrived at the lowest point 
 of the run. In the example referred to, this arc is built of hewn stone ; but sometimes it is constructed 
 »f timber, and not unfrequently of cast-iron plates. Sufficient clearance is of course necessary to allow 
 oi the wheel moving free of the arc, and to this extent there must always be a waste of water ; but 
 when the arc is properly constructed and wrought to the circle, this clearance need not exceed half an 
 inch, which will be the measure of the plate of water which escapes without producing its effect upon 
 the buckets immediately on their passing the plane of the axis. This arrangement is sometimes adopted 
 with good effect in wheels belonging to the class called overshot, and it is applicable in all cases. But 
 when the height of the fall is considerable, and the buckets properly constructed to retain and carry 
 down the water, it is of less importance, as the small loss at the lower part of the revolution bea r s a 
 
SGO 
 
 WATER-WHEELS. 
 
 diminished proportion to the whole effect realized. In the breast-wheel, the buckets are made more flat 
 and radial than in wheels which receive the water near the summit, and are therefore not so well adapted 
 to retain the water. The only reason assignable for this difference of form is, that it to some extent 
 economizes the fall ; for in every wheel the lip of the bucket must descend below the water-level before 
 any water can enter it, and consequently there is a loss of fall incurred in filling equal to something 
 more than the depth of the bucket ; and the lower the fall is, this will evidently bear a greater ratio to 
 the entire value of the water. 
 
 The power of all large wheels is taken off by a second shaft carrying a pinion, which geers with a 
 large spur-wheel bolted upon the shrouding of the water-wheel. This spur-wheel is cast in parts or 
 segments and bolted together, and is generally, though not invariably, an internal wheel. When there 
 is considerable breadth between the shrouds, it is of importance to take the power at both sides, as 
 shown in Figs. 3804 and 3806, and always from the loaded arc of the water-wheel. By this arrangement, 
 all strain is taken off the arms and journals of the wheel, wnich otherwise would be excessive. The 
 circumstances also accommodate themselves to this arrangement, in so far as the centre of pressure 
 of the mass falls usually within the depth of the shrouding, and renders any calculation unnecessary. 
 
 Wheels of a diameter up to 20 feet are frequently fitted with cast-iron 
 arms, instead of being of the spider construction of that above referred to ; 
 and they have an advantage in being more rigid though more heavy, and 
 inerefore more severe on their journals. The common and best mode of 
 fitting the cast-iron arms to the centres is shown by Fig. 3806. The 
 arms A A are cast with projecting cheeks on their lower extremities, which 
 are planed and fitted into the dressed recesses of the centre, and are secured 
 generally by three, but sometimes by one bolt. The other extremities are 
 cast with T ends, which are likewise planed and fitted into corresponding 
 recesses in the shrouds, and fastened by two bolts, and sometimes by ad- 
 justable keys. 
 
 It is not uncommon to find the arms of spider-wheels secured with nuts instead of cotterals, as shown 
 in the two examples given ; but the latter mode is usually reckoned preferable, on account of the diffi- 
 culty of maintaining the truth of the wheel in screwing up the nuts to the requisite degree of tightness ; 
 and the cotterals has the further advantage, that they are more secure, and less expensive. The con- 
 structive details of this mode of fitting have been already shown, and have been highly approved by 
 some of the first builders both in Europe and in this country. The example to which these drawings 
 refer is not only one of the very largest, but perhaps the most complete in its details, of any water- 
 wheel yet constructed. 
 
 To determine the capacity of the wheel answering to a given supply of water, it is necessary to take into 
 account the rapidity with which the buckets are filled and emptied ; in other words, the angular velocity 
 of the wheel. This velocity, it has been remarked, ought to be slightly less than that of the lamina of 
 water falling into the wheel to prevent the back of the buckets, as they pass the receiving point, from 
 striking against the descending stream, and thereby not only wasting a portion of the water by throw- 
 ing it over the circumference of the wheel, but also diminishing the useful effect of that which passes 
 into the buckets by the counteraction produced on the wheel. 
 
 The velocity of the stream may be generally determined in the following manner. Thus at the dam- 
 sluice — if H be the depth to the centre of the sluice-opening, the velocity U of efflux will be ex- 
 pressed by 
 
 m being a coefficient depending for its value upon the particular form of the sluice-gate, but which may 
 be taken generally = 0’64 ; and g the symbol of gravity = 32'2. Consequently, if we substitute the 
 numerical values of these symbols, we shall have the simple arithmetical rule 
 
 U = 7-13371 
 
 And if the lead or course be short, and h the total fall from its origin to the extremity where the water 
 is delivered upon the wheel, the velocity u at that point will be found from the formula 
 
 U = y/ U 2 + 2 (jll, 
 
 m which U and g have the same significations as above. 
 
 But if the lead be of considerable length, it will be necessary to take into account the retardation 
 which the water experiences in its passage. This is found from a calculation of the surface which the 
 water passes over in its transit, and knowing approximately the velocity with which it moves. If we 
 call u (found as above) the ultimate velocity of the stream, and U that at its origin, calculated at the 
 dam-sluice, then ■§■ ( u -J- U) will be nearly the mean velocity in the lead ; and dividing the number ol 
 cubic feet of water to be delivered in a second by this mean velocity, the quotient will be the mean 
 transverse area A of the current ; and this divided by the mean width of the channel will give the depth 
 of water. Now, the frictional retardation of a stream of water varying according to the amount of sur- 
 face of the fluid in contact with the bed upon which it moves, is, therefore, inversely as the whole quan- 
 tity of fluid — that is, for any given quantity of water, the resistance being as the surface, of the bottom 
 anil sides of the channel directly, and as the whole quantity of water inversely, the diminution of velcc 
 S L 
 
 city will be as — ■ in which L is the length of the channel in feet, and S the surface (bottom ano 
 A 
 
 sides) over which the water glides. The retardation is expressed by 
 
 3800. 
 

 WATER-WHEELS. 
 
 8G1 
 
 J S SL/U + w \ 5 
 
 in which c is a coefficient determined by experiment = -007. If, therefore, U be the velocity due to 
 the pressure at the sluice, and h be the total fall upon the channel, the ultimate velocity will be ex 
 pressed by 
 
 Y 
 
 = v 7 
 
 IP + 2 g h — 0-007 
 
 SL/U + u\ 
 
 ~X\ tT J 
 
 It is scarcely necessary to remark that this is only an approximation, which, however, may bo con- 
 sidered sufficiently correct for all practical purposes ; and if greater exactness be desired, the value ol 
 V thus found may be substituted for u and the equation resolved anew for a nearer value of V. 
 
 As the value of h can be modified at pleasure in making the channel, it is of moment that these cal- 
 culations be considered previous to determining the position of the shuttle. If the channel be already 
 existing, and it is wished to determine the quantity of water flowing in it, this may be done with suffi- 
 cient correctness, by finding the surface velocity, and multiplying it by the mean cross-sectional area of 
 stream : four-fifths of the quantity thus found will be very nearly the actual quantity flowing in the 
 channel. 
 
 This rule, although often employed, and without material error when the quantity of water flowing 
 is considerable and the velocity not great, is not to be relied upon when more than a rough approxima- 
 tion is desired. In some cases it is of importance to determine exactly the quantity of water supplied, 
 as when a rental is paid for the power, when testing the efficiency of a wheel, or determining the power 
 necessary to impel certain kinds of machinery ; in these, and analogous cases, we must have recourse 
 to more accurate formulae. When the surface of the stream can be correctly ascertained over a portion 
 of the channel, of which the cross-section is nearly uniform, the following rule, which is founded on that 
 of M. de Prony, may be employed with considerable confidence. Let U denote the mean velocity of 
 the stream, (which is sought to be determined,) and V the surface velocity measured by a float in the 
 middle of the stream, both reckoned in feet per second, then 
 
 V + 6-50 
 
 V + 8-92 
 
 X V. 
 
 As an example — let the surface velocity be 5 feet in a second, then will V -4- 6 - 5 = 11 ’5 and V -4- 8'92 
 = 13-92, and 
 
 = — = 'S24 ; therefore, 6 ' 5 ° X V = -824 X 5 = 4-12 feet,' 
 
 V + 8-9 13-9 ’ ’ Y + 8-92 
 
 that is, the surface velocity of the stream being 5 feet per second, the mean velocity U is 4'12 feet. 
 And this velocity being multiplied by the sectional area of the stream, the result will be the volume 
 of water flowing in a second ; and therefore, 
 
 Q = 60 S X U, 
 
 will be the quantity furnished in 60 seconds or 1 minute. 
 
 The maintaining power in a moving volume of water is obviously proportional to the quantity of de- 
 scent in a given space ; when, therefore, the motion is uniform, and is neither retarded nor accelerated 
 by the force of gravitation, it is manifest that the whole weight of the water is employed in overcoming 
 the frictional resistance ottered by the bottom and the sides of the channel ; and it’ the inclination vary, 
 the relative weight, or the force which urges the particles along the inclined plane, will vary as the 
 height of the plane when the length is given, or as the fall in a given distance. The retarding force, 
 which is equal to the relative weight, must therefore also vary as the fall, and the velocity, which is as 
 tire square root of the impeding influence, must be as the square root of the fall ; and supposing the 
 hydraulic mean depth — that is, the depth which a current of water would take if spread out upon a 
 horizontal surface equal to the bottom and sides of its channel— to be increased or diminished, the in- 
 clination remaining the same, the frictional resistance would be diminished or increased in the same 
 ratio ; and, therefore, in order to preserve its equality with the relative weight, it must be proportion- 
 ally increased or diminished by increasing the square of the velocity in the ratio of the hydraulic mean 
 depth, or the velocity in the ratio of its square root. We may, therefore, expect that the velocities will 
 be conjointly as the square root of the hydraulic mean depth and of the fall in a given distance, or as a 
 mean proportional between these two lines. From this reasoning, Eytelwein and some other writers 
 on hydraulics, have deduced*"* rules for determining the mean velocity of large bodies of water. Let <5 
 
 denote the measure of declivity, and d the mean hydraulic depth of the current, then 100 
 
 express the resulting velocity in feet per second — showing that, if the rate of descent were only one in 
 100 X 100, the stream would acquire a velocity represented simply by the square root of the hydrau- 
 lic mean depth. If / denote the fall in feet each mile, the formula for the velocity will take the form 
 
 5280 
 
 100 11 
 
 y/V — 8 -v/o/- 
 
 Hence, the velocity reckoned in miles an hour is expressed by 
 
 11 15 _ 15 _ 
 
 8 '22''/' 5 / — T 6V ,<5 /- 
 
 The square root of the product of the hydraulic depth into the fall each mile in feet being diminished 
 by 1 -1 6th, will hence represent the mean velocity of a river in miles each hour. 
 
862 
 
 WATER-WHEELS. 
 
 * 
 
 This rule, 'which is that deduced by Sir John Leslie for the velocity of water in rivers, may be com- 
 pared with the result of Eytelwein’stformula for the same purpose, as rendered by Dr. T. Young 
 Taking two English miles as a given length, he finds a mean proportional between the hydraulic mean 
 depth and the fall in that space, and inquiring what relation this bears to the velocity in a particular 
 case, finds that, in general, the mean proportional sought is jAths of the velocity in a second. 
 
 In order to test the accuracy of this rule, Dr. Young takes an example which could not have been 
 known to Eytelwein. Mr. Watt observed, as Prof. Robison informs us in the article River, of the En- 
 cyclopaedia Britannica, that in a canal 18 feet wide above, and 7 below, and 4 feet deep, having a fall 
 of 4 inches in a mile, the velocity was 17 inches in a second at the surface, 14 in the middle, and 10 at 
 the bottom ; so that the mean velocity will be 14 inches or somewhat less in a second. Now, to find 
 the hydraulic mean depth, we must divide the area of the section, 2 (18 + 7) = 50, by the breadth of 
 
 50 
 
 the bottom and length of the sloping sides added together, whence we have ■ X 12 = 29T3 inches; 
 
 and the fall in two miles being 8 inches, we have ^/(S X 29T3) = 15'26 for the mean proportional of 
 which — is 13'87, the mean velocity in inches each second. 
 
 29T3 
 
 To test Sir John Leslie’s rule by the same example, we have f — J ft. and S = ■ *' ■ = 2 - 4275 ft. ; 
 
 therefore, if — '8092 nearly, and y/cf = -8996. Hence, — y/i f X '8996 = 1-236 feet; 
 
 8 8 
 
 that is, 14-83 inches, a result in excess of that found by Eytelwein’s rule of 14-83 — 13-87 = 0‘96 inch. 
 
 17 
 
 By M. de Prony’s rule we have, V = — = 1-4167 feet, and 
 
 Y -f 6-50 
 
 Y + 8-92 
 
 which, multiplied by 17, the surface velocity gives 13'1 inches as the mean velocity. And, taking the 
 common rule of deducting a fifth from the surface velocity for the mean velocity of the current, we 
 17 
 
 have 17 — — = 13-6 inches, which does not differ greatly from M. Eytelwein’s rule, in which we have 
 
 most confidence, from our own experience, when the volume of water is very great. For smaller quan- 
 tities of water, such as we find in leads cut to supply bucketed wheels, the modification which we have 
 given of De Prony’s rule is much more convenient, and we have found it, in general, very correct. 
 
 It is frequently difficult, and sometimes impossible, to apply any of these rules to determine the 
 volume of water furnished ; and it is often of importance, as when considerable accuracy is desired, to 
 resort to more than one mode of measurement. In all ordinary experiments of this kind, there is a 
 certain degree of uncertainty arising from inaccuracy of measurement ; it is therefore of importance to 
 have the means of checking the result of one rule by that obtained by a different process. The follow- 
 ing method, which is not only simple and generally applicable, but likewise admitting of considerable 
 
 o?07. A 
 
 accuracy, will therefore be useful. This consists in erecting a notch in some convenient part of the 
 watercourse where the velocity is not great. The notch is easily formed in leads of moderate size by 
 aboard A A, Fig. 3806, stretched across the channel, and having a rectangular part AcdA cut or 
 notched out in the manner shown in Fig. 3807, and through which the whole of the wate v will be made 
 
WATER-WHEELS. 
 
 SOB 
 
 to pass. The notch-board being fixed, a rod B must be fixed vertically in the channel a few yards be- 
 hind, and having a mark n upon it at exactly the level of the edge c d, of the notch. The water being 
 then permitted to descend in the lead, let its depth nm upon the rod B be carefully noted in inches, 
 then taking from the second or third column of the annexed table the quantity corresponding to one 
 inch of width at the depth noted, multiply that quantity by the whole width in inches, and the result 
 will be the whole quantity flowing through the notch in cubic feet per minute. 
 
 Thus, if the depth from m to n on the rod B be 16 
 inches, and the width of the notch a b be 7 feet = 84 
 inches, then corresponding to 16 inches is 25'8 cubic 
 feet in the second column, and which multiplied by 
 84 gives 2167‘2 cubic feet as the whole quantity pass- 
 ing through the notch in a minute. 
 
 The quantity corresponding to 16 in the third column 
 is 2 7 '4 1 3 cubic feet, which multiplied by 84 gives 
 2202'7 cubic feet as the supply per minute, which is 
 35^- cubic feet in excess of the result obtained by em- 
 ploying the second column. This discrepancy arises 
 from the third column being calculated for weirs 
 which discharge more water in a given time than 
 notches, on account of their offering less impediment 
 to the motion of the fluid. A weir is a wall built 
 generally of solid masonry across the channel, with a 
 parallel plank fixed horizontally on edge along the 
 top of the building. The plank is termed the waste- 
 board, and the water flows over it along the whole 
 breadth of the channel, and thus suffers no lateral 
 obstruction as it does in meeting the notch-board, in 
 which the passage is usually contracted. But if the 
 notch be made equal in width to the width of the 
 channel, then this column ought to be employed, since 
 under these circumstances the conditions are strictly 
 analogous, and the notch may be called a weir. 
 
 When the preceding table cannot be conveniently 
 applied, the value of Q, the quantity of water dis- 
 charged in a minute, will be found very nearly from 
 the expression, 
 
 Q = 200HL ,/ H, 
 
 in which H is the height m n of the surface level of the water above the sole of the notch, and L the 
 
 4 
 
 width, all-in feet. Thus taking the example given above, we have H = - ft., and T, = 7 ft., therefore, 
 
 Depth of the 
 upper edge of 
 the waste- 
 board below 
 
 Cubic feet of water 
 discharged in a min- 
 ute by every inch of 
 the notch, accord- 
 
 Cubic feet of water 
 discharged in a min- 
 ute by eveiy inch of 
 the waste-board of a 
 
 the surface, in 
 inches. 
 
 ing to Du liuat’s for- 
 mula. 
 
 ments made by Mr. 
 Smeaton. 
 
 i 
 
 0403 
 
 0-428 
 
 2 
 
 1-140 
 
 1-211 
 
 
 2-095 
 
 2-226 
 
 4 
 
 3-225 
 
 3-427 
 
 5 
 
 4-507 
 
 4-789 
 
 6 
 
 5 925 
 
 6-295 
 
 7 
 
 7-466 
 
 7-933 
 
 8 
 
 9-122 
 
 9-692 
 
 9 
 
 10-884 
 
 11-564 
 
 10 
 
 12-748 
 
 1 3-535 
 
 11 
 
 14-707 
 
 15-632 
 
 12 
 
 16-758 
 
 17-805 
 
 13 
 
 18-895 
 
 20-076 
 
 14 
 
 21-117 
 
 22-437 
 
 15 
 
 23-419 
 
 24-883 
 
 16 
 
 25-800 
 
 27-413 
 
 17 
 
 28-258 
 
 30-024 
 
 18 
 
 30-786 
 
 32-710 
 
 3S08. 
 
 4 4 
 
 Q = 200 X - X 7 v/ - — 2155-3 cubic feet. 
 
 3 3 
 
 To find the mean curve described by the lamina of fluid discharged upon the circumference of the 
 wheel, when the water is carried over its summit, it is necessary, in the first place, to determine the 
 velocity of the fluid vein at that point. Its rate of descent from the horizontal line inn, in Fig. 3808, 
 may then be assigned by the following method : 
 
 Let u designate the velocity of the water at the ex- 
 tremity of the course, and a the angle, which the direc- 
 tion-board of the spout forms with the horizontal line 
 m n, and which expresses the deflection of the line 
 denoting the velocity u from the plane of the horizon ; 
 then the curve described by the sheet of water will be 
 expressed by the equation 
 
 gz 1 , , 
 
 V = ; — r s h x tan a, 
 
 J 2 v? cos 2 a n 
 
 x being the abscissae measured upon the horizontal 
 plane, taken at half the depth of the fluid vein, where 
 the mean velocity is u\ and y the vertical ordinates referred to the same initial point at n. 
 
 This equation may be expressed verbally thus : 
 
 To find the ordinates of the mean curve described by the water issuing upon a wheel from a shuttle 
 of which the direction-board is inclined at a small angle with the horizontal plane, corresponding to any 
 given horizontal absciss® of the curve, multiply double the square of the velocity u of the water at the 
 extremity of the direction-board by the square of the cosine of the angle formed by its direction with 
 the horizontal plane, and by this product divide the square of the given abscissa multiplied into g ■= 
 S2-2. To the quotient which results, add the product of the same abscissa, multiplied into the tangent 
 of the angle a of the velocity u with the plane in n. The sum will be the ordinate sought —y. 
 
 In giving any values to x equal to 3 inches, 6 inches, 9 inches, &c., we obtain the corresponding values 
 o f ' y, and a curve being traced through them, will give the path of the middle film of water 
 
864 
 
 WATER-WHEELS. 
 
 When the direction-board is horizontal, we have 
 
 and, therefore, 
 
 a — 0, cos a = 1, tan a = 0, 
 
 'J * g „ 
 
 * = 277 = 2 ^’ 
 
 which is the following verbal rule: divide 32 2 by double of the square of the velocity of tie water 
 at the extremity of the course, and multiply the quotient by the square of the given abscissa x. The 
 product will be' the ordinate y , corresponding to the value assigned to x. 
 
 If the water falls over a waste-board, as in breech and breast wheels, the mean velocity of the 
 sheet will be obtained by taking 4-5ths of that due to the whole height H of the level of the water 
 above the edge of the board. 
 
 Thus, u = - — 
 
 5 v /2jiH=6'4^/H 
 
 This velocity will project it only slightly in a horizontal direction ; and, if much accuracy is required, 
 it is easy to determine for any such case the parabola described by the stream. 
 
 To exemplify the rule, as applied to the overshot-wheel, we must, in the first place, determine the 
 point of the circumference where the mean jet encounters the wheel, draw a tangent to the parabolic 
 curve described by the fluid in the direction of its final velocity V ; and, having done this, we calculate 
 the height due to the velocity u , adding the distance of the point of contact below the origin of the 
 curve. The velocity due to the sum of these heights is that with which the water falls into the 
 buckets. 
 
 Thus let it be required to find the final velocity of the water falling upon a wheel of 111 f ee t diam- 
 eter, of which the axis is 10 inches before the vertical line, falling from the extremity of the direction- 
 board, which has an inclination of 1 in 12 ? If we suppose that the extremity of the direction-board is 
 •8 inch above the wheel, and that the piean velocity of the lamina of water is 4 inches, and its velocity 
 9 '84 feet in a second, then, 
 
 tan a = = 0’083, cos a = 0'995, u = 9'84 ft. 
 
 32 ‘2 x I 2 
 
 y = -5 + 0-083 x = 0468 x 2 + 0'083 x. 
 
 J 2 (9-84 X 0-995) 2 
 
 Taking, therefore, any values of x at pleasure, we find the value of y by a simple arithmetical process. 
 Thus, let x — 3 in., we have 0168 x 2 - 0168 X 9 = T512 and 0'083 x — 0147 ; hence y = T512 + 
 0147 = 2'259 inches. 
 
 The intersection of the curve thus determined with the circumference of the wheel is about 2f inches 
 below the middle film of the vein at the extremity of the direction-board ; that is, from the origin of the 
 curve, and the height due to the velocity, 9'84 feet, a second being 1-52 feet, the total height due to the 
 required velocity is 1 foot 9 inches, and, consequently, the velocity with which the water will strike the 
 bottom of the buckets will be y/64'4 X 115 = 10 6 feet in a second. 
 
 The lead or channel by which the water is supplied to the wheel ought obviously to be so constructed 
 that it shall consume as little as possible of the available fall. As a first condition, it ought therefore to 
 be as nearly straight as the local circumstances will admit; for at every bend which it makes, a portion 
 of the impulse of the water will be absorbed by the concave side of the channel, and therefore a greater 
 declivity will be necessary to bring forward a given quantity of water in the unit of time. Moreover, 
 the centrifugal force created at the sinuosities has the effect of raising the surface and augmenting the 
 abrasion of the banks at those points ; and if by any accident a breach be produced, the sweep of the 
 current must necessarily tend to enlarge the concavity with an accelerated progression. The inclination 
 ought likewise to be as nearly as possible uniform — more correctly, it ought to be so regulated that the 
 transverse sectional area of the stream shall remain constant throughout its whole length. If the course 
 be constructed of masonry, it is obvious, from the remarks made respecting the effects of the hydraulic 
 mean depth on the velocity of the current, that it will be of advantage to build the side-walls verti- 
 cally ; and in order that the resistance may be the least possible, the depth of the stream should be 
 equal to half the width. This rule may be followed when the quantity of water is small ; but in leads 
 of large area, the width at bottom is usually from four to six times the depth. When the depth is con- 
 siderable, the walls are moreover built with a certain amount of batter. Mr. Eytelwein, indeed, recom- 
 mends that the breadth at the bottom be fds of the depth, and at the surface 3J. The area of such a 
 section is twice the square of the depth, and the hydraulic mean depth fds of the actual depth. 
 
 The slope here recommended is 4 to 3, forming an angle to the plane of the horizon with the water- 
 way of 37° ; whereas, in this country, the ratio commonly adopted for canals is 3 to 2, making an angle 
 of 34°, which is far more than sufficient for any watercourse intended merely for the purpose under 
 consideration. The best angle to insure durability will, however, very much depend upon local circum- 
 stances, and the material of which the banks are constructed or composed. 
 
 Having fixed upon the dimensions of the lead and the intended depth of the current, if we call A 
 the area of its transverse section, and q the volume of water to be brought forward in a second, the 
 
 mean velocity U, which the water must have, will be expressed by U = And calling S the peri- 
 
 inetrical surface, (bottom and sides,) and I the inclination or fall in 100 feet, which the channel ought to 
 have to give the velocity U required, we shall have 
 
 I = f U (-00042 U -j- -00444 J. 
 
 .A. 
 
WATER-WHEELS. 
 
 865 
 
 Thnt is, to find the fall in 100 feet of length of the channel, multiply '00942 by the given velocity TJ : 
 add to the product '00444 ; multiply the sum again by the velocity, and the product by the perimetri- 
 cal surface, and divide the last product by the transverse sectional area of the channel. 
 
 Thus, if the quantity of water to be brought forward be 40 cubic feet every second, in a channel of 
 18 feet, width, the depth of the water not to extend feet, we shall have, 
 
 A the area of the section = 10 X 2'5 ft. = 25 sq. ft. 
 
 40 
 
 U the mean velocity = — — = T6 feet in a second. 
 
 1 5 
 
 S the perimetrical surface = 10 -j- (2 X 24) = 15 feet; therefore I = — — X 1'6 (0'00942 X 1'6 -f- 
 
 •00444) ='0585 feet, the fall in 100 feet of length of the channel. 
 
 This rule, at least the latter part of it, referring to the inclination, may be dispensed with when the 
 channel is short. In cases where the whole run does not exceed a length of two or three hundred feet, 
 the bottom may be made quite level, as the depth of the water in the channel will give sufficient fall 
 for the velocity required, provided the area of section be made of ordinary magnitude. 
 
 Equal care is usually necessary in the construction of the tail-race as in that of the lead-run ; for it is 
 of quite as much importance that the water leave the wheel-pit freely, as that it be brought forward 
 with as little loss of fall as possible. The same rule will apply in both cases ; but without some .judg- 
 ment in the engineer to apply it, with allowance for sinuosities, it is better to err on the side of excess 
 in the case of the tail-race, than to encounter the risk of flooding the wheel in backwater. 
 
 The quantity of water to be used being ascertained by the preceding methods, the capacity of the 
 wheel may be readily determined. If q denote the volume of water flowing in a second of time, d the 
 distance between two buckets reckoned upon the exterior circumference of the wheel, and v the velocity 
 of those points of the circumference, it is evident that in one second there will pass under the apron of 
 
 the shuttle a number of buckets equal to — , and consequently that each will receive a volume of water 
 equal to q divided by — ; that is, = q — . But it is manifestly necessary that the bucket be capable of 
 
 containing not only this quantity, but even a quantity about three times as great, otherwise a portion of 
 the water will be spilt from the buckets too soon, and without producing its effect upon the wheel. If 
 l represent the width of the bucket, that is, the width of the wheel within the shrouds, and s the area 
 of its transverse section— more correctly, the area of the section of the mass of fluid which it .contains at 
 the moment it passes the jet — s l will represent its capacity, and in relation to the section of the bucket 
 itself we shall have 
 
 *1 = 3 
 
 d q 
 
 o-=180-T_ 
 W M hi 
 
 M being the number of buckets in the wheel, and N the number of revolutions which the wheel makes 
 in a minute. And since 
 
 d = - - and v — — , therefore l = ■ T — - 
 
 M 60 M N S 
 
 which is the width of the wheel when Q is tl.c volume of water to be employed upon it in a minute, and 
 when it is expected to realize the maximum mechanical effect of the water. 
 
 We proceed to establish the values of these symbols from considerations involved in the modus ope- 
 rands of the wheel ; but for practical purposes, we may remark that, with slight variation, s may be 
 
 Q 
 
 taken = \ square foot ; l — 4'5 - and M = 2'88 D. 
 
 We have already seen that the whole dynamical force of the stream of water employed in impelling 
 a wheel of any form is expressed by W 11 ; but as the whole height H can in no case be rendered effec- 
 tive, we have found it necessary to affect this product by a coefficient m, which is always a proper frac- 
 tion, expressing the ratio of the force expended to that realized by the particular mover. To ascertain 
 the theoretical value of m, which often, however, differs considerably from the actual value, let us take, 
 in the first place, the overshot-wheel, as the simplest case which the problem presents. Referring to 
 Fig. Slid, let the horizontal lines M A and F B represent the higher and lower water levels ; the verti- 
 cal distance A B will then indicate the entire height H of the fall. If we divide this height into three 
 parts — A c the part comprised between the higher surface of the water and the point where the stream 
 strikes the wheel ; c D equal to the height of the arc of the wheel, which may be considered as filled 
 with water ; and B D the distance between the point at which the water may be considered to be wholly 
 discharged and the bottom of the fall — this division will enable us to particularize and estimate the losses 
 which take place between the several partial limits, and therefore between the extreme limits A and B. 
 
 Within the limit c and D we have the whole effect of the expenditure realized upon the wheel, since 
 the whole volume of fluid acts constantly, and with its whole weight in the vertical direction, it must 
 realize upon this part of the wheel an effect corresponding to the height through which it descends, and 
 yield a result which, in conformity with the notation adopted, will be expressed by W X c D. The 
 height A c is that due to the velocity with which the water falls into the buckets, and with which it 
 would strike the start-boards, if it did not experience any diminution between the shuttle and the point 
 of impulse. But this condition does not hold true ; for at the point where the fluid encounters the wheel, 
 the height due to the velocity is not A c, (which, for brevity, we shall put = A,) but to a height h — ^ A. 
 The value of the coefficient ^ will depend upon various conditions. In the first place, there arises a loss 
 equivalent to a loss of velocity from the contraction of the fluid vein ( vena contractu) which the fluid ex 
 Vol. II. — 55 
 
866 
 
 WATER-WHEELS. 
 
 periences in its passage through the orifice of the shuttle ; secondly, from the resistance offered by the 
 surfaces over -which it passes ; thirdly, from the dispersion of the filaments of the iluid by striking 
 against the oblique plates of the buckets ; and fourthly, from the oblique direction with which the mean 
 volume of fluid arrives at the bottom of the buckets. This obliquity may, in general, be taken at 30°, 
 causing a diminution in tire value of A of 0T4, and consequently a corresponding diminution of the force 
 of the impulse. All these causes combined are fouud according to local circumstances, such as a good 
 or bad arrangement of the shuttle and direction-plate or apron, to be equivalent to form two tenths tc 
 three-tenths of the whole value of A. Let A a be the portion of the height A c, representing the value 
 of n A, the remaining part a c will then represent the height A — ^ A, due to the actual velocity V of the 
 jet, and consequently equal to -0155 V 2 . 
 
 From what has been before explained regarding the impulsive action of a current of water, this height 
 will be subject to two other reductions : the one A' = '0155 v 2 is that due to the velocity v of the wheel 
 in feet per second, and therefore increases with that velocity ; the other A" = '0155 (V — vf is the 
 height due to the velocity lost by the shock, and which, on the contrary, decreases as the velocity v in- 
 creases. The sum of these losses will be the least possible, or ’0155 j v l + (V — vf j- will be a minimum 
 when 9 = 1 V. They will be respectively equal, that is, each will be | X '0155 V 2 = i A (1 — f ) ; and 
 the two together, that is, a b -f- b d, will be equal to -J A (1 — fi). In this case of minimum loss, the re- 
 maining part d c, which is all of the fell A c that can be regarded as effective, will therefore be equal 
 also to -J A (1 — n) = -J a c, and consequently less than -J- h = \ A c, that is, than half the head reserved 
 between the surface level of the water and the point at which it is received upon the wheel. 
 
 Although the sum of the two losses h' and h" cannot thus be less than $ A (1 — //), we know that it 
 can be, and is, indeed, almost always considerably greater, and increases as the difference between hi 
 and A" increases. It will obtain its maximum , if one of the two quantities, A" for example, should be- 
 come zero, giving rise to the condition V = v. In that case we have h' = -0155 V“ = A (1 — n), that is, 
 ab = a c, showing that no part of the fall A c remains effective. But in practice this condition can never 
 arise, unless by miscalculation of the primary values of V and v. This last must always be less than 
 the former, and consequently h" must always have a real value ; and in every case where h" is greater 
 than zero, it is manifest, from what has gone before, that a certain portion, however small, of the height 
 A c must remain effective. Theoretically, this is shown to be less than -J- A ; and under the very best 
 arrangements it cannot, in practice, be expected to amount to § A, and in ordinary cases it ought not tc 
 be assumed greater than -J A. As a general rule in practice, it may therefore be admitted, that in bucket- 
 wheels, about two-thirds of the part of the fall comprised between the level of the water at the shuttle, 
 and the point where the fluid encounters the wheel, is lost, as respects the effect produced. The actual 
 value of this height A. which may be generally expressed by W j A (1 — v)~ A' — h"\ , will therefore 
 he represented by 
 
 W (A — ! A) = § W A, 
 
 a result which we shall subsequently find is closely analogous to that obtained experimentally as the 
 effect of the best forms of impulsive wheels. 
 
 Since, then, a third only of the part of the fall above the wheel is available as power, whilst the whole 
 of the part from that point downwards to the turn of the buckets, namely, c D, the height of the loaded 
 arc, is entirely realized, it is manifestly of advantage to augment this latter part as much as possible, at 
 the expense of the former. But this augmentation has a near limit, since there would be no economv, 
 but the converse, in raising the point of reception so much, that the water, in arriving at the wheel, would 
 have a less velocity than the buckets. In this case, it could not begin to act upon the wheel, except as 
 a retarding influence, until, by an acceleration of its velocity, it established the necessary condition 
 V v. 
 
 The portion of the fall D B, from the bottom of the loaded arc downwards, is evidently lost, without 
 answering any beneficial purpose. This loss arises from two causes — rather consists of two parts. The 
 part e B is a measure of the loss resulting from the form of the buckets, and the small portion D e of 
 that caused by the velocity of the wheel, or, more correctly, it is a measure of the loss occasioned by 
 the centrifugal force produced in the fluid by the angular velocity communicated to it in its descent in 
 the buckets. Leaving this effect out of view in the mean time, it is evident that, if not influenced by 
 any central force, the surface of the water contained in the buckets would continue horizontal. In pro- 
 portion as the buckets descend, in consequence of the revolution of the wheel, this surface gradually ap- 
 proaches the lip of the containing or front plate of the bucket ; and the instant after it arrives at this 
 position, marked A i , it begins to be discharged, and the bucket will be completely emptied when the 
 face has attained the horizontal position marked k l. The arc F A, which measures the distance of the 
 base of the wheel to the point where the water begins to be discharged, will therefore include the par- 
 tially loaded arc A k and the empty arc k S’. This last is equal to the angle u k l, which the front plate 
 of the bucket makes with the tangent to the circumference, an angle which is known from the rules em- 
 ployed in tracing the lines of the buckets, and which we may here designate by a. The arc F h=F k 
 -j- k A, and this last k h is equal to the angle x h i, which the front plate of the bucket makes with the 
 surface of the water at the point where the fluid begins to be discharged, and which, for brevity, may 
 be called z. We have therefore F A = a-j- '. 
 
 Whatever may be the magnitude of the two arcs of discharge, from these data we can always deter- 
 mine the rate of diminution of the quantity of water remaining in the buckets between the extreme 
 points where it begins to overflow and where it leaves the bucket entirely empty, and therefore can 
 determine the mean arc of discharge, and from this the mean quantity of effect due to the water carried 
 below the commencement of the arc at A, in terms of the whole quantity which the buckets would be 
 capable of carrying in their horizontal position in passing through the height c D. By determining the 
 mean of this arc, we find the point at which, if the whole water were instantly discharged irom each 
 bucket as it passed, the effect upon the wheel would be the same as takes place when it is prolonged 
 
WATER-WHEELS. 
 
 8G7 
 
 over the whole length of the arc h k. Generally, indeed, the mean is the arithmetical mean distance 
 between h and k, and may be expressed by a -f- 1- 2 . If upon A B we take e at such a height that a 
 horizontal line meeting the circumference of the wheel at a point equidistant from h and k, then will 
 e B be the total loss of fall arising from the reversion of the buckets ; and the wheel will yield the same 
 result as if the entire water, instead of being gradually discharged between these points, were carried 
 down to the point e, and then instantly thrown from the buckets. The arc below that point may there- 
 fore be regarded as entirely empty, and producing no effect ; and to designate its relation, we have e B 
 equal to the versed sine of that mean arc, of which the semi diameter of the wheel is the radius ; and 
 therefore putting D to denote the diameter, we shall have 
 
 e B = J D ] 1 — cos (ct + iz)\. 
 
 It may be remarked that the angle z, which the surface of the fluid makes at the commencement of 
 the discharge with the front plate of the bucket, will depend upon the volume of water in the buckets, 
 as well, as upon the form and dimensions of these, both of which are, of course, either known from the 
 rules employed in the design of the wheel, or may be ascertained by direct measurement. 
 
 It remains to determine the loss of head resulting from the centrifugal force produced in the fluid 
 filling the buckets, by the motion of the wheel. This loss is sometimes considerable, although not com- 
 monly reckoned among the influences to which wheels of this class are liable. M. Poncelet was the first, 
 we believe, to direct attention to it, and has established a theorem for its determination, which may be 
 said to complete the theory of the modus operandi of bucketed wheels. 
 
 It has been already stated that if a body move in a circle at 
 a distance x from the centre, its centrifugal force will be express- 
 
 w w v 2 , v . . 
 
 ed by — u 2 x = — . — , when — is put for the angular velocity 
 ff g x x 
 
 with which the body revolves. Now, since every molecule of 
 fluid contained in the buckets of a wheel in motion is subjected 
 to the action of the two forces — that of gravity and the centrifu- 
 gal action — we may confine our attention to one such molecule e 
 w 
 
 of which the mass — may, for brevity of expression, be called m. 
 
 If e ip in the annexed diagram, Fig. 3809, represent the force m g 
 of gravity acting vertically, and e q , measured in the direction of 
 the radius C e, represent the centrifugal force m w a x, the diagonal 
 e r of the parallelogram will be the resultant of the two forces, 
 and may be regarded as representing the measure and direction 
 of a new force replacing the two actual forces ep and e q, and 
 producing upon the molecule the same intensity of action. If we 
 prolong e r until it meets the vertical fine E O passing through 
 
 the centre C in O, this point will be such that C 0 = and, 
 
 Ul 
 
 therefore, is independent of the position of the molecules, and the 
 same for all — all the resultants of the forces converging to that 
 point, which is therefore the centre of action whence all the forces 
 are directed. The surface of the fluid being always perpendicu- 
 lar to the direction of the force which acts upon the molecules, 
 that of the fluid contained in all the buckets will be so to the 
 lines passing to the point 0 from any point of the wheel, and, 
 consequently, the section s t of any given surface will be an arc 
 of a circle having 0 for its centre. 
 
 In the revolution of the wheel, the extremity s of this arc ap- 
 proaches gradually the lip of the front plate of the bucket, and 
 will arrive at it whenever the bucket shall have come into the 
 position A B I. Immediately after it will begin to be discharged, 
 and the discharge will continue until the bucket has descended \ 
 
 to the position A' B' I', where the limiting arc of the fluid surface ''Q 
 
 will have passed under the bucket-plate A' B'. 
 
 In wheels moving at ordinary velocities the surface of the water m the buckets may be regarded as 
 planes perpendicular to fines drawn to them from the centre 0. On this supposition the two arcs of 
 discharge, A E and A E, may be thus determined. The first, that is, the whole arc measured by the 
 angle A C E, is equal to 
 
 G A F = GAB-f BAf-f IAF = a -f- 2 -j- y 
 
 m designating the angle l AF = «OC by y, the point a being equidistant between s' and V. Taking 
 o,g pei pendicular to a C, and calling b the angle which the first of these fines makes with the tangent 
 A G, supposing both produced until they meet, and which will necessarily be equal to the arigl j 
 A C a ■ and 
 
 Z. OaC = /_ g at' = /_ G A t' — b. 
 
 Moreover, the triangle 0 a C gives 
 
 -4n a 0 0 : a C : : sin 0 a 0 : 0 C, 
 
 (i f* 
 
 sin y : p : : sin [a -f Z — b) : — 
 
 v 
 
 that is, 
 
868 
 
 WATER-WHEELS. 
 
 in ■which r is the dynamical radius of the wheel, and p the same radius, diminished by half the depth a 
 the buckets. From this analogy we obtain 
 
 sin y ■- 
 
 p v* sin (a + " — b) 
 
 ~7 ^ ' 
 
 The angle b being generally very small, will very slightly influence the value of ?/, and may, there- 
 fore, be neglected in determining the angle of discharge without sensible error; but by way of compen- 
 sation, we may substitute for p the dynamical radius r, making 
 
 sin y = — . sin ( a -4- z). 
 gr 
 
 To find the measure of the arc A' E : if we take y' to denote the angle a' 0 E we shall have A’ E 
 = Z. (« + y')- And from the same species of reasoning employed for y we find 
 
 • , ^ ■ 
 sin ?/ = — . sin a. 
 gr 
 
 From these values we might establish a general expression for the mean arc of discharge ; but, as 
 already remarked, this does not ditfer sensibly from the arithmetical mean, and may therefore be rep- 
 resented by a + \ z -f- i y + -J y'. And reverting to Fig. 3808, its versed sine will be represented by 
 D B, which is the whole loss of head resulting from the form of the buckets and the centrifugal force 
 conjoinedly, and may thus be calculated previous to the construction of the wheel. If we designate 
 this loss by k'", we shall have 
 
 h"' = lD jl — cos(a + \z + \y + ly')\ 
 
 As an example of the arithmetical process of determining this loss of head from a priori data, let the 
 diameter of the wheel be 37-J feet, the number of buckets 92, the width l = 3'55 feet = 3 feet 6 J inches, 
 and the depth 12'8 inches. The breadth A B of the first plate of the buckets is 1-522 feet, and a line 
 joining A I = 1 -683 feet. The angle GAB which A B makes with the tangent A G to the circumfer- 
 ence is 31° 37' = a ; B A I = 9° 8' ; and A I B = 53° 10' ; the surface of the triangle B A I B is there- 
 fore = '20344 square feet = s'. The dynamical radius r of the wheel is 17'935 feet, and the distance d 
 between the buckets measured on the circle described by that radius is 1'225 feet ; the velocity v at the 
 same circle = 8'2 feet in a second. The quantity of water furnished in the same unit of time is 6'3 
 cubic feet = q. The section s of water contained in a bucket before it begins to discharge will there- 
 fore be 
 
 s 
 
 q d 5-3 X 1'225 
 
 lv~ 3-55 X 8 2 
 
 0-22299 sq. ft. 
 
 But this section being greater than -20344 = .s', shows that the water surface meets the sole at some 
 point V higher than I. Now the angle z, that is, the angle which the surface of the water makes with 
 the face-plate of the bucket, will be equal to the sum of the angles B A I and I A V. 
 
 To find this last we may take, without sensible error,* 
 
 tan I A t' — 
 
 2 (s — s') 
 
 •0391 
 
 A I 2 — 2 (s — s') tan A B I 2'8325 — -006286 
 
 = tan 0° 47' 34"; 
 
 therefore, z = A B I + 1 A t' — 9° 8' -j- 0° 47' 34" = 9° 56' nearly. 
 To find y and y' we have, for the first, 
 
 v* . , , N (8-2) 2 
 
 sin ?/ = — sin (a 4- z) = 
 
 J gr K ^ ' 32-2 X 17-935 
 
 X sin (31° 37' -+- 9° 56') = sin 4° 26' very nearly. 
 
 sin y' = — . sin a - 
 gr 
 
 ( 8 - 2) 2 
 
 32-2 X 17-935 
 
 X sin 31° 37' = sin 3° 30' very nearly. 
 
 For the whole ineffective arc of discharge we have, therefore, 
 
 a + i-- + ll/ + hy' = I0 0 S3' ; 
 
 and from this we obtain as the total loss 
 
 h'" — i X 37-J (1 — cos 40° 33') = 4-502 feet 
 
 If we decompose this into the losses incurred by the form of the buckets and the centrifugal force, we 
 find for the former 
 
 c B = ^ X 37 £ (I — cos 36° 35') = 3-694 feet ; 
 and . • . c D = (4-502 — 3'694) feet = 0'808 feet. 
 
 These parts are, therefore, very nearly as 100 to 22 ; consequently, retaining these numbers, the loss ol 
 fall below the loaded arc is shown to be increased by the centrifugal force communicated to the fluid 
 from 100 to 122. 
 
 In conformity with the principle before indicated, we must, in order to arrive at a complete theoret- 
 ical expression of the value of the fall, subtract these several losses, and multiply the remainder by the 
 weight of water for the total effect, which will then be expressed by 
 
 W (H — tl h — W — h" — h"’). 
 
 But this expression being deduced entirely from theoretical considerations, we must, in order to com- 
 
 * When the point (' falls below I, that is, when s' is greater than s, the formula for z becomes 
 
 2s- AB 
 
 tan z = A B . 2 + 2s CQt ( lg0 o _• A j} jy 
 
WATER-WHEELS. 
 
 869 
 
 pare it with the results of experience, applicable to every particular case, introduce our coefficient of 
 reduction m, when we will have as the actual effect developed by the wheel 
 
 E = i#W (H — — h‘ — h" — /<"'). 
 
 From this it therefore appears that in every bucket-wheel the ultimate effect will be increased as the 
 five quantities //, h, li', h" . h'" are diminished. Now these have respect, 
 
 *<, to the construction of the shuttle and watercourse, which ought accordingly to be adapted with 
 care to the particular case ; 
 
 h, to the diameter of the wheel, which, therefore, ought to be as great as the other conditions will 
 admit, (it being understood here that the wheel is constructed on the overshot principle ;) 
 
 h' and h", to the difference of velocity between the water and the wheel for a given value of h ; a 
 condition which will be satisfied the more nearly as the velocity of the wheel approaches half the ve- 
 locity of the water at the moment it arrives at the bottom of the buckets ; 
 
 h" 1 , to the proper disposition and form of the buckets, and a small velocity of the wheel, by which 
 the water will be carried to the lowest point possible of the fall before it is discharged. 
 
 The only trustworthy experiments on wheels of this class, which have been published, are those of 
 Mr. Smeaton, made in 1759, upon a small model wheel of two feet diameter. Various details are, 
 however, wanting to enable us to compare hi9 results with the preceding formulae — especially the form 
 and dimensions of the buckets. The following table contains the summary of his results : 
 
 No. 
 
 Whole 
 
 descent. 
 
 Water 
 expend- 
 ed in a 
 minute. 
 
 Turn9 at 
 the max- 
 imum in 
 a min- 
 ute. 
 
 Weight 
 raised at 
 the max- 
 imum. 
 
 Power of 
 the whole 
 descent. 
 
 Power of 
 the wheel. 
 
 Effect. 
 
 Ratio of the 
 whole power 
 and effect. 
 
 Ratio of pow- 
 er of the 
 wheel and 
 effect. 
 
 Mean 
 
 Ratio. 
 
 
 Jnch. 
 
 lb. 
 
 
 lb. 
 
 
 
 
 
 
 
 i 
 
 27 
 
 30 
 
 19 
 
 64 
 
 810 
 
 720 
 
 556 
 
 10 : 6-9 
 
 10 : 7-7 
 
 
 2 
 
 27 
 
 56-| 
 
 16! 
 
 144 
 
 1530 
 
 1360 
 
 1060 
 
 10 : 6-9 
 
 10 : 7-8 
 
 
 3 
 
 27 
 
 56| 
 
 20$ 
 
 12! 
 
 1530 
 
 1360 
 
 1167 
 
 10 : 7-6 
 
 10 : 8-4 
 
 s 
 
 4 
 
 27 
 
 63! 
 
 20! 
 
 13! 
 
 1710 
 
 1524 
 
 1245 
 
 10 : 73 
 
 10 : 8-2 
 
 
 5 
 
 27 
 
 76§ 
 
 21! 
 
 15! 
 
 2070 
 
 1840 
 
 1500 
 
 10 : 7-3 
 
 10 : 8-2 
 
 0) 
 
 6 
 
 28! 
 
 73| 
 
 18$ 
 
 17! 
 
 2090 
 
 1764 
 
 1476 
 
 10 : 7- 
 
 rR 
 
 00 
 
 O 
 
 ca 
 
 7 
 
 28jr 
 
 96$ 
 
 20$ 
 
 20! 
 
 2755 
 
 2320 
 
 1868 
 
 10 : 6-8 
 
 10 : 8- 
 
 o 
 
 8 
 
 30 
 
 90 
 
 20 
 
 19! 
 
 2700 
 
 2160 
 
 1755 
 
 10 : 6-5 
 
 10 : 8T 
 
 Cl 
 
 GO 
 
 9 
 
 30 
 
 96§ 
 
 20$ 
 
 204 
 
 2900 
 
 2320 
 
 1914 
 
 10 : 6-6 
 
 10 : 8-2 
 
 10 
 
 30 
 
 113! 
 
 21 
 
 23! 
 
 3400 
 
 2720 
 
 2221 
 
 10 : 6 5 
 
 10 : 8-2 
 
 o 
 
 11 
 
 33 
 
 56§ 
 
 20$ 
 
 13! 
 
 1870 
 
 1360 
 
 1230 
 
 10 : 66 
 
 10 : 9- 
 
 > a 
 00 
 
 12 
 
 33 
 
 106§ 
 
 22$ 
 
 214 
 
 3520 
 
 2560 
 
 2153 
 
 10 : 6T 
 
 10 : 8-4 
 
 13 
 
 33 
 
 146§ 
 
 28 
 
 274 
 
 4840 
 
 3520 
 
 2846 
 
 10 : 5-9 
 
 10 : 8T 
 
 O 
 
 14 
 
 35 
 
 65 
 
 19$ 
 
 164 
 
 2275 
 
 1560 
 
 1466 
 
 10 : 6-5 
 
 10 : 9-4 
 
 JO 
 
 15 
 
 35 
 
 120 
 
 214 
 
 254 
 
 4200 
 
 2880 
 
 2467 
 
 10 : 5-9 
 
 10 : 8-6 
 
 
 16 
 
 35 
 
 163! 
 
 25 
 
 26! 
 
 6728 
 
 3924 
 
 2981 
 
 10 : 5-2 
 
 10 : 7 6 
 
 o 
 
 1. 
 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 
 10. 
 
 11. 
 
 From this table we perceive the small effects produced by an increase of the head A c — li above 
 the wheel. On the general results, he observes, that “ the power of the water computed from the 
 height of the wheel only, appears to observe a more constant ratio” than that between the power of 
 the water reckoned from the whole descent and the ultimate effect. Thus the ratios in column 9 differ 
 from that of 10 : 7 - 6 to 10 : 5'2 ; whereas, taking the mean set down in column 11, “we find the ex- 
 tremes to differ no more than from the ratio of 10 : 8T to 10 : 8'5 ; and as the second term of the ratio 
 gradually increases from 8T to 8‘5, by an increase of head from 8 inches to 11 inches, the excess of 8'5 
 above 8T is to be imputed to the superior impulse of the water at the head of 11 inches above that of 
 3 inches ; so that, if we reduce 8T to 8, on account of the impulse of the 3-inch head, we shall have the 
 ratio of the power, computed upon the height of the wheel only, to the effect at a maximum as 10 : 8, 
 or as 5 to 4 nearly ; and from the equality of the ratio between the power and effect, subsisting when 
 the constructions are similar, we must infer that the effects, as well as the powers, are as the quantities 
 of water and the perpendicular heights multiplied together respectively.” 
 
 These inferences are corroborative of the principles which we have attempted more formally to illus- 
 trate ; but we must also quote his remarks “ concerning the velocity of the circumference of the wheel, 
 in order to produce the greatest effect,” as they are still frequently appealed to in justification of an 
 erroneous interpretation of a true doctrine. The doctrine is thus stated by the author : — “ If a body is 
 let fall freely from the surface of the head to the bottom of the descent, it will take a certain time in 
 falling ; and in this case the whole action of gravity is spent in giving the body a certain velocity : but 
 if this body in falling is made to act upon some other body, so as to produce a mechanical effect, the 
 falling body will be retarded ; because a part of the action of gravity is then spent in producing the 
 effect, and the remainder only giving motion to the falling body : and therefore the slower a body de • 
 
870 
 
 WATER-WHEELS. 
 
 »cends, the greater will be the portion of the action of gravity applicable to the producing a mechanical 
 effect ; and in consequence the greater that effect may he. 
 
 “ If a stream of water falls into the bucket of an overshot-wheel, it is there retained until the wheel 
 by moving round discharges it : of consequence the slower the wheel moves, the more water each bucket 
 will receive ; so that what is lost in speed, is gained by the pressure of a greater quantity of water acting 
 in the buckets at once ; and, if considered only in this light, the mechanical power of an overshot-wheel 
 to produce effects will be equal whether it moves quick or slow : but if we attend to what has been 
 just now observed of the falling body, it will appear that so much of the action of gravity, as is em- 
 ployed in giving the wheel and water therein a greater velocity, must be subtracted from its pressure 
 upon the buckets, so that, though the product made by multiplying the number of cubic inches of water 
 acting in the wheel at once by its velocity will be the same in all cases ; yet as each cubic inch, when 
 the velocity is greater does not press so much upon the bucket as when it is less, the power of the wa- 
 ter to produce effects will be greater in the less velocity than in the greater : and hence we are led to 
 this general rule, that cteteris paribus, the less the velocity of the wheel, the greater will be the effect 
 thereof." 
 
 According to this view of the subject we ought to introduce into our formula a further reduction of H 
 depending upon the velocity of revolution, and which would therefore be a function of v. But if the 
 mode in which li" has been obtained be observed, it will be found that the circumstance which Mr. 
 ijmeaton had in view is there included. It is admitted that the gravitation of the fluid in the buckets 
 cannot at the same time be producing pressure and velocity ; but we have laid it down as a condition, 
 which Mr. Smeaton also insists upon, that the water must have a higher velocity than the circumference 
 of the wheel at the moment of its passing into the buckets. This condition being fulfilled, it is then 
 clear that as no additional velocity has been generated in the fluid, after it has entered the buckets, no 
 part of its power is thereby consumed below that level, and that all its effect will be realized upon the 
 wheel. In other words, the effect of the volume of water on the loaded arc will be expressed by 
 W X c D. 
 
 This may be exhibited somewhat more formally, and as a preliminary step let it be required to prove 
 that the weight of fluid carried in the loaded arc of the wheel, from the level of c to the lower level D, 
 is equal to the effort which would be exercised by the weight of a prism of water G II placed at the 
 extremity of the dynamical radius O P, the height of the prism being equal to c D, and the area of its 
 base equal to the cross-section of the fluid arc, if the water in the buckets were uniformly distributed, 
 and formed a continuous arc. To show that this is true statically, it will be sufficient to prove that the 
 moments of pressure are in the two cases equal. For this purpose let it be supposed that the lengtl 
 of the fluid arc is divided into an infinite number of small elementary arcs, such as m n having a cross 
 section <r. If then we designate by <p the specific gravity of the fluid, we shall have a . m n . <p as the 
 weight of the small arc m n. And since it acts vertically, the distance between the direction of its pres- 
 sure and the centre of rotation will be the horizontal line r s. Thus then we have as the moment of its 
 pressure a . mn . <j> . r s. But the triangles m n t and rOs are similar ; hence mn . r s = 0 r . p q, 
 and therefore, 
 
 a . m n . $ . r s =■ a . <p . O r . p> q. 
 
 Now the sum of all the partial moments will be the moment of the entire arc, and will be found by 
 multiplying the common factor a . <j> . 0 r by the sum of all the small heights p q of the elementary 
 arcs ; this sum is evidently /<? = c D ■ the entire moment will therefore be a . <p . O r . c D. But that 
 of the prism G H is manifestly — o . f G H . 0 P ; and since GH = cD and Or = OP, the two mo- 
 ments are equal. 
 
 If we now bring into view the dynamical conditions imposed by the motion of the wheel, and keep 
 in view that no motion is communicated to the water within the limits of the arc, we have as data a 
 pressure applied at P in the direction of movement a . <p ■ c D, and a velocity at that point of v feet per 
 second : the force impressed will therefore be expressed by a . <p . c D . v. And if q be the volume ol 
 water flowing in a second, with a continuous section a , and velocity v communicated independently of 
 the motion of the wheel, and acquired before it reached it, we have q = <j . v ; and w being the weight 
 of the volume q, we have besides w = <p . q. Taking the values of a and $ in these two equalities, and 
 substituting them in the expression above of the force impressed, it becomes 
 
 q w 
 
 — . — . c V . v — io . c D, 
 v q 
 
 which is the condition we undertook to demonstrate, and upon which, it will be observed, the velocity 
 of the wheel has no influence. 
 
 The best data which we possess for determining the value of the coefficient m in our formula of the 
 actual efficiency of the wheel is a table of experiments furnished by M. D’Aubuisson containing all the 
 conditions. The mean of these cases gives m ='8997, and the highest value is '917, and the lowest 
 •874. We may, therefore, without serious error put m = '9. The other terms may also be simplified 
 for the purposes of ready application. Thus the three terms nh, h', h" , taken together, we have already 
 shown, do not differ widely from § h ; and, except in extreme cases, h"' will not vary more than be- 
 tween 4 and } of the diameter of the wheel. Let us assume the mean of these extremes, namely, l- 1), 
 and substitute these quantities with a value of m = 0'9 in our formula, it will then be reduced to the 
 following : 
 
 E = 0'9 W (H — § h — 1 D), 
 
 and by putting Q = the number of cubic feet of water furnished in a minute, and expressing the effect 
 in units of horse-power, conformably to the principle before explained, w<“ have 
 
 E = '0017 Q (H — ^ h — ^ B). 
 
WATER-WHEELS. 
 
 871 
 
 As an example, let the quantity of water be 1000 cubic feet a minute, and the fall 25 feet; in this case 
 the wheel would be made about 22 feet diameter ; therefore § h = 2 feet and ^ D = 3§ feet. Hence, 
 the value of the fall would be reduced to 25 — (3 — (- 3§) = 19J feet, and this multiplied by 1000 = 
 19333. Finally, 19333 X •001'? = 32-87 horse-power. 
 
 This formula may also be employed to determine the volume of water which it would be necessary 
 to employ, with a given head, to obtain any required amount of power — a problem which very fre- 
 quently occurs in practice. 
 
 In this we have confined our attention to the case of the overshot- wheel, on account of its being the 
 most obvious ; but the same formula may, by a very slight modification, be applied to determine the 
 effect of a breech- wheel. The modification referred to is simply the replacing of ^-D by its assumed 
 equivalent It 1 ", by which we have 
 
 E = -0017 Q (H — § h — h'"). 
 
 We replace h'", because in wheels of this kind its value ought to be always less than in the overshot 
 arrangements. The breech-wheel, as we have already seen, has usually a diameter somewhat greater 
 than the height of the fall ; and as h'" is proportional to the diameter, we have by this arrangement 
 the advantage of making it as small as possible within the limits of practice. We can, indeed, increase 
 the diameter at pleasure, and thereby proportionally increase the length of the loaded arc — the grand 
 source of power in the bucketed wheel of whatever form. 
 
 Robertson Buchanan, in his Essay on Water-Wheels, has endeavored to fix the proportion of the 
 radius of the wheel to the height of fall to yield a maximum effect, but seems to have left out of view 
 the effect of the centrifugal force, and to have sujtposed the wheel to revolve in an arc— which is, in- 
 deed, the usual arrangement now adopted. The following is his mode of calculation : — Let c — that 
 portion of the circumference which is to be loaded with water — that is, the portion of the half circum- 
 ference below the point at which the water flows upon the wheel ; and let x — the arc comprehended 
 between that point and the horizontal plane passing through the axis of the wheel ; also make b — the 
 area of the stream supplying the buckets. Then the solid which represents the effective force, that is, 
 
 ( c 1 — 2 x*\ 
 
 — J , and this is to be the greatest pos- 
 
 (p" 2 op 
 
 sible, or = a maximum. By the principle of maxima and minima, this takes place when x = c 
 
 (1 — y/ 4) or x = 0'2929 c. Accordingly, the arc c — x must be a quadrant, and the arc x = 37’27°. 
 
 From this it appears that the wheel will produce its greatest effect when the diameter is so propor- 
 tioned to the height of the fall that the water flows upon the circumference at a point 90° — 37'27° — 
 52-73° (nearly 62J- degrees) distant from the summit of the wheel. 
 
 If R, then, be radius of the wheel to the extreme edge of the bucket, and h the height of fall meas- 
 ured to the point where it may be delivered upon the wheel, and which may be called the effective 
 height, then we shall have 
 
 R = * _ = 
 
 1 -f- sm 37| 1'605 
 
 Since sin 37i degrees = -305- We have also by reduction R = -623 li. 
 
 The effective height of the foil is less than the entire height H by as much as is necessary to 
 give the water the required velocity, which may be taken generally at 10 feet in a second, or 1-J 
 feet of fall. 
 
 The French mechanicians calculate a somewhat greater diameter for their wheels than that given by 
 the foregoing rule. Instead of laying on the water at 52-J degrees from the summit, as is commonly 
 done in this country, they lay it on at a distance of 60°, that is, 30 degrees above the horizontal plane 
 
 passing through the axis of the wheel. Accordingly R = — = §7i. They also allow, as above recom- 
 
 mended, li feet of the fall to give the required velocity to the water. 
 
 No line of demarcation has yet been determined to separate this species of wheel from the breast- 
 wheel, except that this name is applied when the water is received upon the wheel at a greater dis- 
 tance from the summit than 52| degrees. But it has not been decided when this rule ought to be set 
 aside, and the wheel become a breast-wheel. A notion, not without foundation, prevails among mill- 
 wrights that a wheel of large diameter is more advantageous than one of small diameter ; in a wheel 
 of large diameter the influence of the centrifugal force is less, and the mass in motion being greater, 
 the movement is more uniform and may be proportionally slower, which, in the case of a low fall, is 
 no inconsiderable advantage. There is, however, the disadvantage of additional friction upon the jour- 
 nals, and which, as these wheels are usually very broad, goes far to counterbalance the loss arising from 
 centrifugal force. 
 
 As the question is therefore entirely one of practice, and incapable, we believe, of a theoretical solu- 
 tion, it may be stated as an opinion founded on a good example, that the diameter of the wheel, even 
 for very large quantities of water, may be made to conform to the rule above given, down to 12 feet 
 diameter. The example which we have in view is a double wheel of that size, using at least. 3000 
 cubic feet of water per minute very satisfactorily. The same size of wheel might be used till the fall 
 descends to about 6 feet, when a wheel on the undershot principle will be found less expensive and 
 equally efficient. Under these circumstances the wheel will act partly by the impulse and partly by 
 the gravity of the water — that is, partly as an overshot and partly as an undershot wheel ; its effect 
 may therefore be ascertained by computing the effect due to the difference of level between the surface 
 of the water at the penstock and the point where it strikes the wheel, and adding the result to the 
 effect, realizable from the height of a fall equal to the difference of level between the point where the 
 
872 
 
 WATER-WHEELS. 
 
 water meets the circumference of the wheel and the level of the tail-water, and which may be calculated 
 by the methods above indicated. 
 
 Undershot-wheels . — By undershot we understand here those varieties of wheels which move chiefly 
 by the direct impulse of the fluid. In construction they differ little from the bucketed wheel, except 
 that the buckets are replaced usually by radial floats upon which the impulse of the current is received. 
 They are, also, usually confined in an arc, below the level of the water-line, to confine and economize 
 the motive power; but, as this arrangement is also common to bucketed wheels, especially when the 
 fall is low, it cannot be regarded as a peculiarity. In this form of wheel, especially if the volume of 
 water be considerable, the spider construction is, however, only admissible when the power is taken off 
 at the circumference by a pinion placed slightly above the point of impulse and on the same side, 
 't here is, then, only the small portion of the sole-frame put on strain by tension, between the two points. 
 But, wdten the power is taken off at the axis, the construction ought to be of . the more rigid kind, other- 
 wise the continually changing direction of the strain, acting through a leverage equal to the radius of 
 the wheel, will speedily prove fatal to the points of connection, if in any degree elastic. 
 
 The water is admitted upon the wheel by a sluice or shuttle in its immediate vicinity, as in the case 
 of the bucket-wheel. What has been stated in reference to the loss of head experienced by the water 
 passing through an opening in its course is therefore applicable in this case as before. It is also of 
 moment, both on theoretical and practical grounds, that the sluice be placed as closely upon the wheel 
 as other considerations will permit ; and that the retaining cheeks of the aperture, inside of the sluice, 
 be slightly contracted, answering to the natural contraction of the stream after passing through the 
 orifice, in consequence of the resistance which it there encounters. The sides of the course or arc in 
 which the wheel moves, must necessarily be parallel ; but, immediately on passing the vertical plane 
 passing through the axis of the wheel, the floor ought to deepen and the sides expand and leave the 
 water as much space to diffuse itself over as possible. This arrangement is shown in Figs. 3810 and 
 3811, as far as it is applicable with a sluice-framing entirely constructed of wood; but, when the cod 
 struction is of iron, the confinement of the water may be made much more complete. 
 
 3810 . 
 
 Supposing the floats to be placed radially, their breadth or depth in the direction of the radius ought 
 obviously to be such, that in the rising of the water against the float which it first strikes, the portion 
 which tends to pass over its superior edge shall not be thrown against the back of the succeeding float. 
 Any action of this kind would manifestly be attended with a corresponding diminution of the effect of 
 the wheel; and ought, therefore, to be avoided, as perhaps the most serious error which is liable to be 
 committed in this form of wheel. This source of loss may, however, be, in general, entirely avoided, 
 by giving to the floats a depth of about three times the thickness of the lamina of water acting upon 
 them* The thickness of the lamina is usually from four to six inches, giving the range of depth of the 
 floats from twelve to eighteen inches. The velocity with which the fluid precipitates itself upon the 
 floats, ought also to be taken into account in providing for its expansive movement. The distance of 
 the one float from the other, measured upon the exterior circumference of the wheel, may be generally 
 taken equal to the depth. Their number will, of course, depend upon the diameter of the wheel, and 
 this is almost arbitrary. W e will, however, endeavor briefly to indicate the general principle which 
 ought to be kept in view in fixing the diameter, without entering upon any strict investigation of the 
 question. 
 
WATER-WHEELS. 
 
 873 
 
 As a consequence of the general theory already explained, it follows that the dynamical effect of the 
 wheel is dependent upon the relation which the velocity of the floats bears to that of the water ; but 
 this relation is manifestly independent of the diameter. The velocity due to the current of water to be 
 used is always an ascertainable quantity, and may therefore be regarded as known. Another deter 
 ruinate element of the calculation is the number of revolutions which it is desirable the wheel should 
 make in a certain unit of time, as a minute, in order that the effect may be transmitted to the working 
 points, with a rate of velocity the most advantageous for the particular purposes intended, and obtained 
 
 3811. 
 
 expressed by 
 
 60 u u 
 
 = 111 1 N 
 
 And to obtain an effect approaching the maximum, we may assume u = 2-4 y H ; and therefore the 
 diameter expressed in terms of the velocity and height of fall will be 
 
 19T X 
 
 2-4 v/ H 46 
 
 — N — = \r V 11 vei 7 nearly. 
 
 Thus, supposing the fall to be 6 feet, and the number of turns per minute required to be 10 = N; 
 then the diameter will be 4k X ,/ 6 = 4 6 X 2-45 = 1 Ilf feet nearly. This is nearly the minimum 
 diameter of wheel which would under any circumstances be employed; 12 feet to 25 feet may indeed 
 be taken as the usual range ; but unless the volume of water be extraordinarily great — and then breadth 
 is better than diameter — we cannot conceive of any advantage, other than may arise from some pecu- 
 liarity in the nature of the machinery to be impelled, which may not be obtained with a diameter of 
 16 feet to 18 feet. It is, however, to be observed, that the smaller the diameter the greater is the nicety 
 of adjustment required to make the water yield its effect upon the buckets ; and possibly the errors 
 which have been committed in this particular have led to the common opinion that a wheel of large 
 diameter is always in practice the most effective. 
 
 38 12. 
 
 Before the introduction of Poncelet’s system of curved floats, various attempts were made to increase 
 the efficiency of the undershot-wheel, by placing the floats at some determinate angle with the circum- 
 ference. And where the wheel moved in backwater, and especially in an unconfined channel, a certain 
 beneficial effect was experienced. But in the ordinary cases of a confined course or arc, with proper 
 provision for tail-water clearance, these schemes do not seem to have been attended with any advan- 
 tage. According to Bossut’s experiments, indeed, the result appears to indicate that the radial float is 
 the most efficient. Taking the effect obtained with the radial float as unity, the results which he 
 obtained with (he angular positions noted, arc thus stated: 
 
 Angle of float 0° 8° 12° 16° 
 
 Comparative effect, 1 0 949 0 956 0’99S 
 
o74 
 
 WATER-WHEELS. 
 
 Showing that at least no advantage is derived from feathering the floats, as it is denominated. In aa 
 indefinite volume of fluid, the case is, however, different ; the inclination of the floats favors, not the 
 action of the impelling fluid, but their disengagement. This is manifest when it is observed that aa 
 60 on as the radial float passes into water, having a less velocity than its own, it begins to be retarded ; 
 and besides, in rising to the surface, it tends to lift with it a portion of the fluid, which, acting by ita 
 weight in the contrary direction to that of the wheel, also proportionally diminishes the useful effect. 
 
 This is sometimes obviated at great expense, in large wheels placed in situations where the fall is 
 very small and liable to be flooded, by rendering them capable of being raised and lowered at pleasure, 
 in conformity with the state of the river. The mechanism for this purpose is generally worked by 
 manual labor ; but sometimes also it is rendered self-acting, as in the case of some wheels worked by 
 the tide in situations where the tidal oscillations are considerable. In these the floats are usually, 
 though not always advantageously, inclined to the radius to assist the other arrangements. 
 
 Various other schemes for increasing the efficiency of impulsive wheels have been resorted to. One 
 of these was to place a lodging on' the ends of the floats to confine the action of the fluid ; but with 
 very little beneficial effect ; and, it is obvious, that if any arrangement of this kind was likely to be ox 
 advantage, it could be most effectually secured by placing the floats within slnouds, as in the common 
 bucket-wheel — a form of construction not uncommon. Another supposed improvement, still common 
 in some parts of Europe, though never introduced into this country, and only applicable to very 
 narrow wheels, is to form the floats of cylindrical arcs, with the axis of the cylinder in the direction oi 
 the radius of the wheel, and the concave face of the arc opposed to the motion of the water. This 
 arrangement is stated to possess certain advantages, but we cannot conceive that they can possibly be 
 60 marked as to compensate the additional cost of construction ; and we must still believe that the plain 
 float with shrouding is both the simplest and most complete of all the deviations which have been at- 
 tempted, excepting, indeed, M. Poncelet’s application of the curved float, and even in this the advantage 
 does not so much consist in the form of the float, as in the other beneficial adaptations with which it is 
 associated. 
 
 To understand the action of the water upon the floats of a wheel of the kind under discussion, it io 
 necessary to observe that the moment the sluice is raised, the fluid precipitates itself against the first 
 float which obstructs its passage, and, in consequence, an accumulation takes place, which ultimately 
 succeeds in putting the wheel in motion, and gradually accelerates its velocity until an equilibrium is 
 established between the force of the current and the resistances to be overcome. In proportion as the 
 velocity of the wheel increases, the pressure of the current becomes less, since this action is proportional 
 to the relative velocities ; and very soon the acceleration, which gradually diminishes, becomes imper- 
 ceptible, and finally ceases ; and the wheel, after a certain number of revolutions, in consequence of 
 the velocity impressed upon it, and in consequence also of its inertia, continues to revolve as of itself, 
 e ;t her with a motion perfectly uniform, or with a velocity oscillating between limits imposed by the 
 varying nature of the resistances, and which may be reduced in effect to a mean continuous velocity 
 always ascertainable. 
 
 Supposing the wheel to derive its effect entirely from the impulse of the current, and to obtain no 
 advantage from confinement in an arc, by which a certain amount of the weight of the fluid is made to 
 act in aid of the impulsive force, the dynamical effect, considered theoretically, of any given weight W 
 of water upon a float receding before the stream with a velocity of v feet in a second, is expressed by 
 
 y(V — r) v . 
 
 Hut it may be questioned whether the same effect will be produced upon a suite of floats presenting 
 themselves successively to the current, usually two and three at a time, and under various angles of in- 
 clination. On this point we derive our most important information from experience ; but admitting, in 
 the mean time, that the action of the impulse, although not equal, is of the same kind, and susceptible 
 of an expression of the same form as that above, we shall ultimately succeed in comparing the. results 
 of experiment with those of calculation. 
 
 In the expression above, when the wheel is moved by a confined current, v is the only variable quan- 
 tity. If v = 0, the effect is also cipher, for a machine which does not move yields no power. The power 
 will also be cipher, when Y = v, since, as before remarked, if the wheel move at the same rate as the 
 current, it can receive no motive effect from the fluid. It is still more obvious that v cannot be greater 
 than V. The limit is therefore between v = 0 and v = V, and between these extremes there will be a 
 maximum of effect. If, then, we differentiate the variable part (V — v) v, and equate to zero in the 
 usual manner, we have 
 
 V d v — v d v — 0 ; whence v — Y, 
 
 showing that the effect of the wheel is the greatest possible when it moves with half the velocity of the 
 stream. 
 
 W 
 
 Now, the pressure of the water upon the floats being — (V — v), this will also be a measure of the 
 
 resistances (including all the passive resistances) overcome by the wheel, since the moments of pressure 
 must obviously be equal in every case of equilibrium ; hence, if in this expression we substitute for v its 
 equivalent -J- Y, we have, as the measure of the load when the dynamical effect is a maximum, 
 
 w X V 
 2 9 
 
 And the dynamical effect being equal to the load multiplied into the velocity of motion, viz., v = $ V, 
 we have, using tins last as the measure of the velocity of the wheel. 
 
WATER-WHEELS. 
 
 875 
 
 V 2 
 
 IW X equivalent to -5- W H, 
 
 2 9 
 
 when H is put to denote the height of fall due to the velocity V, as before explained. 
 
 If, therefore, V be the whole velocity of the stream, and H the entire fall due to that velocity, thk 
 result shows that the greatest possible effect which can be realized from a wheel moved entirely by the 
 impulse of the fluid, is only half of the mechanical power of the water expended ; that is, considering 
 both cases theoretically, is only equal to half the effect which a wheel acting entirely by the gravity of 
 the fluid, ought to realize. But even this moiety is subject to reduction, and can be only distantly ap 
 proached in practice. 
 
 We do not, unfortunately, possess many experiments upon which we can implicitly rely, with wheels 
 of this kind. We have many of a mixed kind, in which the effects of impulse and gravity are combined, 
 but few in which the impulsive action alone appears. Those of Mr. Smeaton, indeed, stand nearly alone 
 in importance and accuracy ; and, fortunately, they are complete in the necessary data. Although the 
 model apparatus with which they were made was small, the well-known accuracy of the experimenter, 
 and the purpose for which the investigation was undertaken, warrants the confidence which they have long 
 commanded. The wheel was the same in diameter as his overshot model, viz., 2 feet, and was, indeed, 
 adapted to the same apparatus. The power was measured directly by raising a weight vertically by 
 a cord over a pulley; and perhaps the only objection which can be validly urged against the results, 
 consists in his neglecting the additional friction thereby produced at the journals of the wheel. The 
 data for this correction is, however, furnished, and may still be applied. 
 
 We subjoin the author’s table of results, the columns of which are fully explained by the hcadimjt 
 placed over them : 
 
 6 
 
 c* ® 
 
 o ‘o 
 
 ’3 
 
 X 
 
 Turns of the wheel un- 
 loaded. 
 
 Virtual head deduced 
 therefrom. 
 
 Turns at the maximum. 
 
 'p 
 
 of 
 
 0> 
 
 o 
 
 5 
 
 | Load at the maximum. 
 
 1 
 
 Water expended in a | 
 minute. 
 
 I 
 
 Power. 
 
 Effect. 
 
 Ratio of the power and 
 effect. 
 
 Ratio of the velocity of 
 the water and wheel. 
 
 Ratio of the load at the 
 equilibrium, to the 
 load at the maximum. 
 
 •sjuouiuodrj 
 
 • ‘ 1 
 
 i 
 
 In. 
 
 33 
 
 88 
 
 in. 
 
 15-85 
 
 30- 
 
 lb. 
 
 13 
 
 oz. 
 
 10 
 
 lb. oz. 
 10 9 
 
 275- 
 
 4358- 
 
 1411- 
 
 10:3-24 
 
 10:3-4 
 
 10:7-75 
 
 
 2 
 
 30 
 
 86 
 
 150 
 
 30- 
 
 12 
 
 10 
 
 9 6 
 
 264-7 
 
 3970- 
 
 1266- 
 
 10:3-2 
 
 10:3-5 
 
 10:7-4 
 
 
 o 
 
 27 
 
 82 
 
 13-7 
 
 28- 
 
 11 
 
 2 
 
 8 6 
 
 243- 
 
 3329- 
 
 1044- 
 
 10:3-15 
 
 10:3-4 
 
 10:7-5 
 
 
 4 
 
 24 
 
 78 
 
 12-3 
 
 27-7 
 
 9 
 
 10 
 
 7 5 
 
 235- 
 
 2890- 
 
 901-4 
 
 10:3-12 
 
 10:3"55 
 
 10:7-53 
 
 At 
 
 5 
 
 21 
 
 75 
 
 11-4 
 
 25-9 
 
 8 
 
 10 
 
 G 5 
 
 214- 
 
 2439- 
 
 735-7 
 
 10:3-02 
 
 10:3-45 
 
 10:7-32 
 
 the 
 
 6 , 
 
 18 
 
 70 
 
 9-95 
 
 23-5 
 
 6 
 
 10 
 
 5 5 
 
 199- 
 
 1970- 
 
 561-8 
 
 10:2-85 
 
 10:3-36 
 
 10:8-02 
 
 1st 
 
 7 
 
 15 
 
 65 
 
 854 
 
 23-4 
 
 6 
 
 2 
 
 4 4 
 
 178-5 
 
 1524- 
 
 442-5 
 
 10:2-9 
 
 10:3-6 
 
 10:8-3 
 
 t.ole. 
 
 8 
 
 12 
 
 60 
 
 7-29 
 
 22* 
 
 3 
 
 10 
 
 3 6 
 
 161- 
 
 1173- 
 
 328- 
 
 10:2-8 
 
 10:3-77 
 
 10:9-1 
 
 
 9 
 
 9 
 
 52 
 
 5-47 
 
 19- 
 
 2 
 
 12 
 
 2 8 
 
 134- 
 
 733- 
 
 213-7 
 
 10:2-9 
 
 10:3-65 
 
 10:9-1 
 
 
 10 
 
 6 
 
 42 
 
 3-55 
 
 16- 
 
 i 
 
 12 
 
 1 10 
 
 114- 
 
 404-7 
 
 117- 
 
 10:2-82 
 
 10:3-8 
 
 10:9-3 
 
 
 11 
 
 24 
 
 84 
 
 142 
 
 30-75 
 
 13 
 
 10 
 
 10 14 
 
 342- 
 
 4890- 
 
 1505- 
 
 10:3-075 
 
 10:3-66 
 
 10:7-9 
 
 
 12 
 
 21 
 
 81 
 
 13-5 
 
 29- 
 
 11 
 
 10 
 
 9 6 
 
 297- 
 
 4009- 
 
 T223- 
 
 10:3-01 
 
 10:3-62 
 
 10:8-05 
 
 
 13 
 
 18 
 
 72 
 
 10-5 
 
 26- 
 
 9 
 
 10 
 
 8 7 
 
 2S5- 
 
 2993- 
 
 975- 
 
 10:3-25 
 
 10:3-6 
 
 1 0:8-7 f 
 
 At 
 
 14 
 
 15 
 
 69 
 
 9-6 
 
 25- 
 
 7 
 
 10 
 
 6 14 
 
 277- 
 
 2659- 
 
 774- 
 
 10:2-92 
 
 10:3-62 
 
 10-9- 
 
 the 
 
 15 
 
 12 
 
 63 
 
 8-0 
 
 25* 
 
 5 
 
 10 
 
 4 14 
 
 234- 
 
 1872- 
 
 549- 
 
 10:2-94 
 
 10:3-97 
 
 10:8-7 
 
 2d. 
 
 16 
 
 9 
 
 56 
 
 6-37 
 
 23- 
 
 4 
 
 0 
 
 3 13 
 
 201- 
 
 1280- 
 
 390- 
 
 10:3-05 
 
 10:4-1 
 
 10:9-5 
 
 
 17 
 
 6 
 
 46 
 
 4-25 
 
 21- 
 
 2 
 
 8 
 
 2 4 
 
 167-5 
 
 712- 
 
 212- 
 
 10:2-98 
 
 10:4-55 
 
 10:9- 
 
 
 18 
 
 15 
 
 72 
 
 10-6 
 
 29- 
 
 ii 
 
 10 
 
 9 6 
 
 357- 
 
 3748- 
 
 1210- 
 
 10:3 23 
 
 10:4-02 
 
 10:8-0 5 
 
 
 19 
 
 12 
 
 66 
 
 8*75 
 
 26-75 
 
 8 
 
 10 
 
 7 6 
 
 330- 
 
 2887- 
 
 878- 
 
 10:3-05 
 
 10:4-05 
 
 10:8-1 
 
 The 
 
 20 
 
 9 
 
 58 
 
 6-8 
 
 24-5 
 
 5 
 
 8 
 
 5 0 
 
 255- 
 
 1734- 
 
 541- 
 
 10:3-01 
 
 10:4-22 
 
 10:9-1 
 
 3d. 
 
 21 
 
 6 
 
 48 
 
 4-7 
 
 23-5 
 
 3 
 
 9 
 
 3 0 
 
 228- 
 
 1064- 
 
 317' 
 
 10:2-99 
 
 10:4-9 
 
 10:9-6 
 
 
 22 
 
 12 
 
 68 
 
 9-3 
 
 27- 
 
 9 
 
 2 
 
 8 6 
 
 359’ 
 
 3338- 
 
 1006- 
 
 10:3-02 
 
 10:3-97 
 
 10:9-17 
 
 
 23 
 
 9 
 
 58 
 
 6-8 
 
 26-25 
 
 6 
 
 2 
 
 5 13 
 
 332- 
 
 2257- 
 
 6S6- 
 
 10:3-04 
 
 10:4-52 
 
 10:9-5 
 
 4th. 
 
 24 
 
 0 
 
 48 
 
 4-7 
 
 24-5 
 
 3 
 
 12 
 
 3 8 
 
 262- 
 
 1231- 
 
 385- 
 
 10:3-13 
 
 10:5-1 
 
 10:9-35 
 
 
 25 
 
 9 
 
 60 
 
 7-29 
 
 27-3 
 
 6 
 
 12 
 
 6 6 
 
 355- 
 
 2588- 
 
 785- 
 
 10:303 
 
 10:4-55 
 
 10:9 45 
 
 5th. 
 
 26 
 
 6 
 
 50 
 
 5-03 
 
 24-6 
 
 4 
 
 6 
 
 4 1 
 
 307- 
 
 1544- 
 
 450- 
 
 10:2-92 
 
 10:4-9 
 
 10:9-3 
 
 27 
 
 6 
 
 50 
 
 5-03 
 
 26- 
 
 4 
 
 15 
 
 4 9 
 
 360- 
 
 1811- 
 
 534' 
 
 10:295 
 
 10:5-2 
 
 10:9-25 
 
 6th. 
 
 1- 
 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 
 10. 
 
 11. 
 
 12. 
 
 13. 
 
 
 But it may be observed that several other columns of ratios might be deduced from the data therein 
 furnished, and which would still further illustrate the action of this order of wheels. The last column 
 has reference to the aperture at the sluice for the admission of the water to the wheel. The holes in 
 
87G 
 
 WATER-WHEELS. 
 
 the scale were placed diagonally, and to these a pin was fitted ; so that when the pin was in the same 
 hole, the opening for the water continued the same for all the experiments of that series. 
 
 From this table we find, on comparing the effect pv produced at the maximum with the product i 
 W h, in which h is the virtual or effective head, that the coefficient of reduction m is very nearly 0'64 ; 
 consequently, we shall have 
 
 E or p v = 0 C-t X |W /( = 032 W h. 
 
 The ratio of p v to W /<, we observe, varies from 0 28 to 0 32, giving a mean of 0'30. This led Hr. 
 Smeaton to infer that one-third of the force produced on the floats by the current, may be realized in 
 the larger wheels. 
 
 If we compare the effect realized with the entire power of the water expended, we find that the 
 ratio increases from 0‘16 in the first experiment, when the total head was 33 inches, to 0'25 in the last, 
 when the entire head was reduced to 6 inches. From this it therefore appears, that the greatest effect 
 which can be obtained from a given head of water, acting impulsively, is between a sixth and a fourth 
 of the entire motive force expended ; and in the case of large wheels, it is very doubtful whether even 
 this last result can be obtained, although, as we have already seen, theory indicates as much as W H, 
 or double. 
 
 The ratio of the velocity of the wheel to that of the current gradually augments from 0 34 to 0'52, 
 giving a mean of 0'43. Mr. Smeaton, however, takes 040 as the mean ; and it is worthy of remark that 
 Bossut, in an analogous series of experiments, also adopted the same number. It, however, seems to 
 us, from the nature of the case, that the proper velocity will approximate much more closely to the 
 maximum limit, and will not deviate greatly from 0 50 of the mean velocity of the current, as indicated 
 by theory. 0'45 will at least be, in general cases, a safe number to adopt in practice ; that is, 
 ti = 045 V. 
 
 Another result worthy of notice is the weight or “load at the equilibrium;” that is, the weight which 
 is just sufficient to keep the wheel at rest against the force of the current. This, at an average, is little 
 more than two-tenths greater than the load which the wheel was capable of carrying when yielding its 
 maximum effect. According to theory it ought to be double, for, as already shown, the weight corres- 
 
 ponding to v = 0 is 
 
 W X v 
 9 
 
 and that at the maximum is 
 
 W X V 
 2 9 
 
 The cases to which these observations apply are those in which the velocity of the wheel is adapted 
 strictly to that of the current. But this is not always obtained, and accordingly the coefficient m being 
 a function of v , fluctuates between extremes which it is impossible to comprehend in a general formula. 
 However, when the velocity of the wheel does not fall below certain limits — from a third to two-thirds 
 of that of the current — we may, without much chance of error, especially in excess, assume 0'60 as the 
 c* /efficient, and accordingly we shall have as a general rule, 
 
 W 1 
 
 E = 060 — (V — v)v= — — W (V — v) v = 1-54 Q (Y — v ) v. 
 
 The velocity Y with which the water arrives upon the floats cannot always be easily assigned. It 
 experiences certain losses between the sluice and the point of impulse, but it is not perhaps possible to 
 give a general expression of their amount, even for an individual case, and much less for different forms 
 and conditions of construction. Independent of any reducing influence, we have Y = V 2 g h, in which 
 h denotes the difference of level between the surface of the water in the lead and the centre of percus- 
 sion of the floats, and which can readily be measured. But from Mr. Smeaton's observations on this 
 point, it appears that the loss is sometimes as much as a fifth of this velocity ; and he further remarked 
 that the difference between the actual and calculated velocities diminished as the vertical opening ol 
 the sluice was augmented. In some instances, indeed, where the volume of water was very great, and 
 the head small, he found that V hardly differed from V 2 y h. M. Poncelet also remarked the same 
 circumstance — that the loss of velocity diminishes with the magnitude of the aperture through which 
 the fluid issues. Even in the case of an opening of about 8J inches in height, and with a head of 4^ 
 feet, he had V = 0’99 V 2 g h. This, however, supposes the sluice to be constructed to the best advan- 
 tage ; and to make a slight allowance for untoward circumstances, we may take V =0'95 V 2 g h 
 = 7'6 V h. Substituting this value of V in the preceding result, we have 
 
 E = T54 Q (T6 V h — v) v. 
 
 And, again, putting for v its equivalent JY = 3'8 V h, this expression is reduced to the following con- 
 venient form, 
 
 E = 221 Q h, or Q h, 
 
 ’ 148 
 
 when expressed in units of horse-power. 
 
 This is the case of the purely impulsive wheel ; but in practice it is very rarely found that some 
 slight amount of head cannot be reserved to act by its gravity. Under these circumstances an arc is 
 formed concentrically with the wheel between the point at which the water strikes the wheel, and the 
 lowest level terminating in the vertical plane passing through the axis. The clearance need not exceed 
 •4 inch, and may, if the arc be carefully constructed, be reduced to ’3 inch. To indicate the effect, let 
 II, as before, be the whole height of fall ; and let h be the portion employed in generating the required 
 velocity. After that the water has struck the first float at the level H — h it will afterwards descend 
 by its weight through that height, producing an effect expressed by W (H — h ) ; and the effect c f the 
 W 
 
 impulse being as before — ( W — v) v, we shall have as the sum of these partial actions. 
 
WATER-WHEELS. 
 
 877 
 
 W {(H — /t)+ — (V — v) vy 
 
 But we formerly found in discussing tlie impulsive action in the case of the overshot-wheel that 
 -~(V — v)v— W (h — ^h — h’ — h"), 
 
 in which the three quantities h\ h" have the significations then assigned. We may therefore make 
 use of this expression as more definite. It is, however, in this case subject to two corrections which may 
 be thus exhibited. 
 
 In the first place, when the whole volume of water has expended its impulsive effect upon the first 
 float which it encounters, it immediately begins to descend by its pressure to the bottom of the arc; 
 but let us observe what takes place in the spaces between the floats during the descent. The arc sus- 
 tains a certain amount of the pressure of the fluid, and there is moreover a certain amount of clearance 
 between it and the radial extremities of the floats. A portion of the fluid will therefore escape through 
 this space without producing any effect, since its pressure is entirely exercised upon the superficies of 
 the arc. This must, consequently, be subtracted from W in the expression W (H ■ — h). This loss can- 
 not, indeed, be rigorously assigned, but may be pretty closely approximated by considering that the re- 
 sistance experienced by this water against the face of the arc diminishes the velocity which gravity 
 tends to give it, and that this diminution increases with its descent: also, that this velocity is further 
 diminished by the continual entanglements to which the water is subjected by the varying conditions of 
 the intervals between the floats, and which likewise become greater towards the bottom of the arc ; and, 
 finally, that the velocity is altered by the continual mingling of the descending laminae, corresponding 
 to the several spaces between the floats and the varying positions of the portions of fluid therein con- 
 tained. We may therefore conceive, with all these retarding influences in action, that the velocity ol 
 the ineffectual portion will not differ greatly from that of the floats ; accordingly, in this state of things 
 if we denote by A the cross-section of the plate of water falling upon the wheel, and by a that correa 
 
 ponding to the intervals between the extremities of the floats and the arc, then will W ^ be the por 
 
 tion of fluid lost as regards the effect of pressure ; hence, by subtracting this from W, the expression ot 
 the effect given above, we shall have 
 
 W(1 «)(H-A). 
 
 e A 
 
 In the second place, the portion of the base of the wheel which dips in the water contained in the 
 lower part of the course, loses there a part of its weight equal to the weight of water displaced. In 
 consequence of this loss the equal distribution of the weight of the wheel about the axis of rotation no 
 longer exists ; and the wheel tends to turn in a direction contrary to that of the current. If we repre- 
 sent by p' the diminishing influence of this tendency, this will be a new resistance which the wheel has 
 to overcome, and which ought, consequently, to be added to these other resistances of which the sum 
 is p. We shall then have, taking m as the coefficient of reduction of the results of calculation to those 
 of observation, 
 
 (p rf- p')v —m W j (H — h) (1 -) -f- h -f- /< /t — /V — A"}. 
 
 In practice this formula may be considerably simplified. The quantities p' and 1 — — , sujoposing the 
 
 A 
 
 construction judiciously and carefully finished, will be very nearly proportional to the power of the 
 wheel, that is, to W ; they may, consequently, be comprised in the value of in. We have also before 
 shown that the quantity nh-\-h' + h" is always greater than ^ h, and differs little in ordinary cases 
 from | h. Hence our formula may be reduced by these substitutions to the convenient form, 
 
 E = t»W (H — | h). 
 
 In this the indefinite quantity is in, and, perhaps, the best authenticated experiments, by which its 
 value may be assigned for the particular case assumed, are those of M. Morin, on a wheel constructed 
 by Messrs. Aitken & Steel for the crystal works of Baccarat, in the Department of Meurthe, in France. 
 The diameter of the wheel is 13 feet 3 inches; its width parallel to the axis 12 feet 94 inches; the 
 number of floats 32, of which the breadth in the direction of the radius is 1 foot 4 inches. The whole 
 fall is 6 feet 9 inches, and the versed sine of the arc 6'04 feet. The water is thrown upon the wheel 
 over the waste-board of a sluice, of the same width as the wheel. The results varied with the thick- 
 ness of the lamina of water admitted upon the wheel, as exhibited in the table on the following page. 
 From this table then, it appears that m = 07 72 ; but as this is reputed to be a particularly well con- 
 structed wheel — considerably above the average — we maybe generally safe in taking in = 0'75, by 
 which our formula is reduced to 
 
 E = 0T5 W (H — | h). 
 
 From the same table it appears that the ratio of the effect to the whole power expended, is 0'717 ; 
 this is a good result, and warrants us in taking, as the general expression of effect for a wheel of ordi- 
 nary character under like circumstances, 0'65 W H. 
 
 The effect of curving the floats, as in M. Poncelet’s wheel, is thus indicated : Supposing, in the first 
 place, that the wheel is at rest, and that a film of fluid arrives horizontally with a velocity V upon the 
 lower edge of the float, in continuing to advance it rises along the curve, and during its elevation the 
 velocity which it possessed is gradually diminished, and becomes nothing when it has attained a height 
 expressed by 0'0155 V 2 . The velocity is not, however, lost ; it is simply changed into gravity, in obe- 
 
378 
 
 WATER-WHEELS. 
 
 dience to which the fluid immediately begins to descend upon the curved surface of the float, over 
 which it ascended, and quits it with the same velocity V, which it possessed at the moment it arrived 
 upon it. This velocity is acquired by falling from the height 00155 V 2 , and under the circumstances 
 we have supposed to exist, its direction would be contrary to that first impressed upon the fluid. Let 
 us now assume that the wheel turns with a velocity of v in a second at its periphery. When the fila 
 ment of fluid, having the velocity V, shall have arrived at the float, it will then have a relative velocity 
 
 Velocity of the 
 wheel in feet per 
 secoud. 
 
 V. 
 
 
 Ratio 
 
 of water upon the 
 waste-board of 
 the sluice. 
 
 of effect to power 
 expended VV 11 
 pv 
 
 VV H * 
 
 of effect to virtual 
 head H — 
 pv 
 
 W (H-U/ 
 
 7'65 
 
 Feet. 
 
 0-719 
 
 0-707 
 
 0-762 
 
 3-83 
 
 0-711 
 
 0-734 
 
 0-792 
 
 3T8 
 
 0-711 
 
 0-726 
 
 0783 
 
 2-71 
 
 0714 
 
 0-720 
 
 0-777 
 
 2-40- 
 
 0-714 
 
 0-716 
 
 0-773 
 
 2T3 
 
 0-718 
 
 0-700 
 
 0 755 
 
 
 Mean. 
 
 0-717 
 
 0-772 
 
 of V — v, and it will only be with this velocity that it will commence to ascend upon the curved sur 
 face of the float; it will therefore rise to a height of only 00155 (V — v)\ and after descending, will 
 quit the lower edge of the float with the same velocity V — v. Tut this element will now have itself 
 a velocity v in the contrary direction, for it partakes of the motion of the wheel ; the absolute velocity 
 with which it escapes will therefore be Y — (t> -|- v). Consequently, if v — $ V, the absolute velocity 
 of escape will be Y — V = 0, showing, that if the velocity of the wheel be half of that with which the 
 water arrives, its absolute velocity in quitting the floats will be nothing. We have, therc-fme, the case 
 of a motive current, which experiences neither shock nor loss of velocity at the moment of impulse upon 
 the wheel, and which possesses none at the moment it quits the float ; it has then expended all its 
 movement upon the wheel, and communicated to it all its force. The two conditions, shown to be un- 
 attainable in the bucket and common impulsive wheels, is therefore theoretically attained with this 
 arrangement, so that, if W be the weight of water, and h the height of fall due to the velocity V, we 
 shall have as the expression of effect W h. 
 
 But although this may be nearly true for a simple film, it is not true for a volume or sheet of water 
 of a certain thickness. Those molecules which strike the floats, making an angle more or less great 
 with the element struck, lose both a portion of their velocity and force ; and at the moment when the 
 mass of particles quit the float upon which they have expended their action, their direction is not ex- 
 actly opposite. Besides, as with all wheels which revolve in an arc, a part of the motive fluid escapes 
 without yielding any useful effect. We may, therefore, conclude that the real effect is not W h, but 
 m W h, in which m is some fraction less than 1. 
 
 A series of experiments was undertaken by M. Poncelet for the purpose of determining this fraction ; 
 that is, the ratio between the actual effect realized and the power expended. The annexed table con- 
 tains the most important conclusions. The wheel, it 
 
 may be observed, had a diameter of 11| feet; 30 i ' ] 
 
 floats of 12^- inches depth in the direction of the ra- Ratios, 
 
 dius, and 25 inches breadth between the shrouds. Rise of sluice ' * ' 
 
 From these experiments and observations M. Poncelet in inches. JL. 1[”_ . ZJL . 
 
 concludes : V YV k W H 
 
 1. That the velocity of the wheel which gives the “ 
 
 maximum of effect is 0'55 of the velocity of the cur- o..V’I o -o r.-o n--- 
 
 rent ; but that it might be varied from 0’5 to 0 6 with- „ 
 
 out any marked disadvantage. ^ g™ 
 
 2. That the dynamical effect is not under 0'7 5 W h ^74 zM>a o.qi n '-- 
 
 for low falls with large volumes of water, and may ,, y ^ 
 
 be taken at 0‘65 W h when the volume of water is a ^ 
 
 small and the fall considerable. 1 0 
 
 3. That this same effect, compared with the entire __ 
 
 force expended, namely, W H, may be taken at 0-60 
 
 in ordinary cases, and at 0-50 when the rise of the sluice is very small. 
 
 For those cases which ordinarily present themselves in practice, and supposing the wheels constructed 
 with due care, and to be adjusted to velocities differing little from '55 of the current, we may therefore 
 take 
 
 E = 0’7 5 W h or E = 0 60 W 11. 
 
 Comparing this result with that determined for impulsive wheels having radial floats, it appears that 
 the effect is more than doubled. This conclusion, to which we arrive in both cases by experimental 
 guidance, ought, of course, to decide which of the two forms of wheel ought to be employed in genera] 
 
 Rise of sluice 
 in inches. 
 
 Ratios. 
 
 V 
 
 V 
 
 P V 
 
 Wh, * 
 
 p V 
 
 WH* 
 
 3-937 
 
 0-46 
 
 0-51 
 
 0-46 
 
 8-268 
 
 0-52 
 
 0-70 
 
 0'56 
 
 8-661 
 
 0-60 
 
 0-68 
 
 0-56 
 
 7-874 
 
 0-52 
 
 0-60 
 
 0-52 
 
 11-969 
 
 0-69 
 
 0-81 
 
 0'55 
 
 “ 
 
 0-61 
 
 0-74 
 
 0'55 
 
 
 0-59 
 
 0-63 
 
 0-52 
 
WATER-WHEELS. 
 
 879 
 
 cases. It is admitted that M. Poncelet’s -wheel involves a more precise acquaintance with the nature of 
 the force employed than the common float-wheel ; but nothing beyond the application of a few rules, 
 which any millwright may readily comprehend and apply. These have in part been given in our de- 
 scription of Figs. 3810 to 3812. The extreme and interior circles of the shrouds being drawn such, 
 that o k = i the effective fall when not more than 4 % feet, the circle rn n is described with a radius 
 determined by the following considerations. From the point k at which the water is supposed to meet 
 the exterior circumference of the wheel, draw the line kp perpendicular to the direction of the fluid. It 
 will form an angle of 24° to 28° with the radius. In that line take a point p equal to about a sixth of 
 its length between the circles of the shrouding, within the inner circle, and through that point from the 
 centre of the wheel describe the circle rn n. Then will p k or p q be the radius of the curved float k q ; 
 and similarly all the radii of the other floats will terminate in that circle. Having determined the num- 
 ber of floats, and marked their extremities upon the external circle of the wheel, draw radii from these 
 points to the axial centre, and upon the circle mn set off the corresponding distances from these radii 
 equal to Ip, and the points thus found will be the centres of curvature of the floats. The distance 
 between the floats will be about half that recommended when placed radially, and ought to be formed 
 of sheet-iron both for convenience of making and subsequent economy of action. 
 
 The mode of constructing the arc at the base of the wheel has been explained in describing the 
 figures referred to ; it is further only necessary to observe that every care ought to be employed to ab- 
 sorb as little as possible of the velocity of the water previous to the moment of impulse, and to provide 
 for its escape when it has expended its force upon the wheel. 
 
 It is also to be understood that this species of wheel, or, more correctly, the mode of supplying the 
 water, will not be economical for falls of more than 44- feet ; when the fall exceeds this limit, advantage 
 ought to be taken of its weight as well as of its impulsive force. We conceive, however, that the form 
 of wheel is itself well adapted to this double purpose ; but the water, instead of issuing from the undei 
 pilp-o of the sluice-plate, ought to be directed over it, as over a waste-board ; and the height of the arc 
 ougnt, at the same time, to be proportionally increased. 
 
 Wheels which move in an indefinite current of water, as a river, are usually of a heavier construction 
 than those we have been considering; but differ only in that respect, and in the inclination. of their 
 floats, from the common impulsive wheel. It is usually found of advantage to make them of a dianie 
 ter of 15 to 20 feet, with 12 to 16 floats, of which the best inclination appears from experiment to be 
 30°. Their best velocity — that at which the effect is a maximum — is a third of that of the current ; 
 and, under these conditions, it will be fouud that they yield an effect of about '006 W V 2 of the water 
 received upon the area of the floats — that is, about jj- W h if /t = 0'0155 V 2 . This result may seem, at 
 first sight, surprising, when it is remembered that the effect of the undershot-wheel working in a con 
 fined rectilineal course, does not yield more than J W h ; but it is to be observed that in this last we 
 include the whole volume of water acting ; whereas, in the other, we take into account only the quan- 
 tity received upon the floats, without reference to the large amount which escapes without producing 
 any effect whatever, and which we cannot attempt to estimate. 
 
 This species of wheel is of very rare occurrence ; yet there are numerous situations where it might be 
 employed with good effect. 
 
 Horizontal Water Wheels. In horizontal water wheels, the water produces its effect by impact, by 
 pressure, or by reaction, or by an union of these forces, but never directly by its weight. Impact wheels 
 have plane or hollow pallets or floats on which the water acts more or less perpendicularly. The pres- 
 sure wheels have curved buckets along which the water flows, and the reaction wheels have as their type 
 a close pipe from which the water discharges more or less tangentially. Pressure wheels and reaction 
 wheels are generally very similar to each other in construction ; the essential difference in them being 
 that in the former the ules or conduits between two adjacent buckets are not filled by the water flowing 
 thi-ough them, while in reaction wheels the section is quite filled. 
 
 Impact Wheels. To this class belong that variety of horizontal wheels usually called tub wheels. 
 They consist of inclined pallets or floats on the inner or outer periphery of a drum, and the water is 
 laid on by a short incline at such an angle that it strikes the float at right angles. The inclination of the 
 floats is from 60 to 70° to the horizon. This wheel is extremely simple in its construction, and is found 
 in all parts of the world. In the older saw mills it was almost invariably used for the running back of 
 the carriage. The simplicity of its construction is its chief recommendation : it seldom exceeds in 
 mechanical effect 33J- per cent, of the water expended. The effect of impact wheels is increased by 
 surrounding the buckets with a projecting border or frame, and by forming their surfaces like the bowls 
 of spoons. If we give the buckets greater length, and form them to such a curve that the water leaves 
 the wheel in nearly a horizontal direction, the water then not only impinges on the bucket, but exerts a 
 pressure upon it, and the mechanical effect is proportionately increased. If the water be laid on with- 
 out impact, the wheel becomes a pressure wheel solely. Among this class, though not strictly within 
 the distinction made above between pressure and reaction wheels, may be included most of the wheels 
 constructed on the principle of the smoke jack, the discharge being downwards; such wheels as are de- 
 signated by the French as roues eu cures. 
 
 Reaction Wheels. As a solid body endowed with an accelerated motion, reacts in an opposite direc- 
 tion with a force equal to the moving force ; so it is in the case of water when it issues from a vessel 
 with an accelerated motion from the orifice. If a vessel filled with water be suspended by a cord, and 
 a horizontal aperture be formed near the bottom, the vessel is forced backward, proportionately to the 
 size of the aperture and the velocity of the issuing current. The simplest of all reaction wheels is what 
 is usually termed Barker’s Mill ; a horizontal tube movable on an axis, is furnished with a cross tube 
 extending at right angles across the bottom of the upright tube and connecting with it; this branch is 
 closed at the ends, and orifices are formed near the extremities, one near each end of the tube, on opposite 
 silks • it now the central tube be filled with water, the discharge through the orifice gives a rotarv 
 
880 
 
 WATER-WHEELS. 
 
 motion to the machine, and if the supply be maintained, a permanent motion results, available for prac 
 tical purposes ; by curving the arms, and properly proportioning the capacity of the tubes, the effect 
 may be increased. Reaction wheels have from time to time been popular in this country from their 
 cheapness, hut till very recently they have not been introduced into the larger mills from the defects in 
 their construction and rudeness of workmanship. 
 
 Among the first reaction wheels introduced here were those patented by Q. and A. Parker of Ohio, 
 in 1829, which embodies many improvements which have since been claimed by foreign inventors. 
 
 The claims of the original patent of 1829 which expired 1850, were for the compound vertical per- 
 cussion and reaction wheel, for saw'-mills and other purposes, with two, four, six, or more wheels on 
 one horizontal shaft. The concentric cylinder, with the manner of supporting them. The spouts 
 which conduct the water into the wheels from the penstock, with their spiral terminations between the 
 cylinders. 
 
 Second, the improvement in the reaction wheel, by making the buckets as thin at both ends as they 
 can safely he made, and the rim no wider than sufficient to cover them. The inner concentric cylinder, 
 the spout that directs the water into the wheel, and the spiral termination of the spout between cylin- 
 ders. 
 
 Third. The rim and blocks ; planks that form the apertures in the wheel, and the manner of form- 
 ing the apertures. The conical covering on the blocks, with cylinder or box in which the shaft runs, 
 and the hollow or box gate, in any form, either cylindrical, square, rectangular or irregular. 
 
 Another patent was issued to Messrs. Parker for improvements in water wheels, June 27, 1810, which 
 expired June 27, 1854. The claim is, the placing of the said wheel, or wheels analogous thereto in 
 their construction and mode of operation, within air or water-tight cases or boxes denominated drafts, 
 substantially in the manner, and for the purpose set forth. 
 
 It will be observed that in the first patent, the wheels are placed vertically; this is a convenient form 
 of application to saw-mills ; the shaft of the wheel being used as the crank shaft, connected directly 
 with the saw gate. For most other applications the horizontal wheel is more suitable, and is most 
 economical in the use of water. 
 
 The varieties of reaction wheels at present in operation throughout the country are innumerable, dif- 
 fering in the form of floats, of guides, and of discharge. Among the most prominent are the Foumev- 
 ron and Jouval Turbine, and the Whitelaw reaction wheel. 
 
 Fourneyron's Turbine. Fig. 3813 represents a general vertical section of the entire machine, showing 
 its internal construction. Fig. 3814 is a half vertical section, on an enlarged scale, of the turbine and 
 crown, showing the mode in which these are-fixed to their respective centres, and exhibiting distinctly 
 the manner in which the sluice-cylinder operates. Fig. 3815 is a quarter plan of the same parts as the 
 above, with the sluice-cylinder and top plate of the turbine removed, in order to exhibit the form and 
 relative disposition of the partition-plates of the turbine, and the direction-plates of the crown. 
 
 In 1834 M. Fourneyron received the prize of 6,000 francs offered by the Society for the Encourage- 
 ment of the Arts at Paris, for the construction of the best horizontal wheel on the large scale. This 
 was his first turbine erected at Pont, on the Oguon. In consequence of this decision the turbine excited 
 great attention and discussion among the continental savans ; and it must be remarked, that matters of 
 practical utility are more subjects of interest among scientific men, especially in France, than elsewhere, 
 where every thing of a technical character is considered to belong exclusively to the workshop. 
 
 In an elaborate report of this machine submitted to the Academy of Sciences of Paris by M. Ponce- 
 let, it is stated that the essential quality of the turbine consists in its high velocity, and its capability of 
 working under water without much loss of effect. The expedient of bringing the water horizontally 
 over all the interior circumference of the wheel, and of making it issue through the greater exterior 
 
WATER-WHEELS. 
 
 SSI 
 
 circumference, allows also a large expenditure of power with a machine of very moderate diameter. 
 Finally, it operates favorably under almost any fall, and at any velocity, without suffering any reduction 
 of its effect from the hydrostatic pressure of the water, and which is stated to be a source of great in- 
 convenience in wheels of this class. 
 
 The peculiar character of the machine is sufficiently explained in the description of the figures re 
 ferred to, and which are supposed to represent one of the inventor's most successful applications of his 
 principle ; but, in order to bring the value and relation of the forces more closely into view, the action 
 of the water may be here briefly indicated. Supposing the annular sluice to be so far let down as en- 
 tirely to close the spaces d, which form the communication between the interior cistern b and the chan- 
 nels c of the revolving disk e, which is the turbine, properly so called, if the sluice between the reser- 
 voir and the supply-pipe a be opened, the water will precipitate itself into the cistern b and entirely 
 “fill it. The pressure on the interior of this cistern, as well as on the annular sluice at the orifices^}, 
 will be in proportion to the depth from the higher level of the water, and, therefore, for a unit of are.-, 
 of the surface acted upon, the pressure will be directly as the height H. If, then, the sluice be raised, 
 the water rushes into the channels c with the velocity due to the head of pressure, and in the direction 
 prescribed by the guide-curves, and impinging against the diaphragms of the channels c causes the 
 disk e to revolve in a direction opposite to the direction of impulse, and finally escapes by the external 
 extremities of the channels at the greater circumference of the turbine-disk. 
 
 The lower divisions of the sluice-ring, it may be remarked, are considerably increased in thickness, 
 and rounded to avoid the contraction of the veins of fluid issuing into the channels c, and which would 
 take place, if no provision were made for correcting the oblique motions impressed, when the water is 
 projected through the apertures at the extremities of the guide-curves in a horizontal direction. 
 
 The construction of the machine depends upon the application of a few fundamental principles. Like 
 all other hydraulic motors, its size ought to be proportioned to the effect which it is intended to pro- 
 duce — that is, in effect to the quantities W or Q and H. Thus the interior diameter D, one of the prin- 
 cipal dimensions, is directly as the ratio of these two quantities ; and as the turbine ought to be capable 
 of expending the volume of water Q, arriving to it with the velocity V, the orifices must have an area, 
 determined from the condition Q = A Y, in which we denote by A the sum of the orifices of admission. 
 On the water arriving in the same time upon all the whole interior circumference of the turbine, A will 
 be equal to that surface, (after subtracting the area occupied by the thicknesses of the diaphragms), and, 
 consequently, will be equal to rr D d, in which d denotes the depth of the courses. The proportion 
 fixed by M. Fourneyron, is d— ] D ; and, therefore, by making this substitution, we shall have 
 
 A = | it D 2 = 0-45 D 2 . 
 
 But Q = A V - 0 45 D 2 Y. 
 
 x\nd V = 6 60 y/ H therefore Q = 3 D 2 y/ H 
 
 From this we have the diameter D = 
 
 V 3 y/ II 
 
 This value of D ought, according to the views of the inventor, to be further affected by a coefficient, 
 to allow for the entanglements which the fluid experiences in the cylinder and in entering the turbine, 
 and for the effect of the obliquity with which the water is thrown by the diaphragms upon the mov ing 
 circumference. This coefficient being introduced according to the practice of M. Fourneyron, we have 
 
 It is here assumed that Q is the greatest volume of water which the machine is capable of discharg- 
 ing ; but it is to be understood, that smaller quantities may be employed, and that the machine is 
 capable of working with almost any less quantity without losing any remarkable amount of its pro- 
 portional efficiency. 
 
 The diameter D may thus be taken as a function of the power of the machine, that is, of E, the 
 dynamical effect in units of horse-power. Now, assuming the machine to realize 15 per cent, of the 
 power which it expends, and that <4 is the volume of water supplied in 1 minute, we have 
 
 E 
 
 QH 
 700 ‘ 
 
 Hence, Q 
 
 700 E 
 H 
 
 And, substituting this value of Q in the expression for D above given, it becomes 
 
 D = l-3 
 
 700 E 
 
 hTh 
 
 35 
 
 E 
 
 h 71' 
 
 The exterior diameter, in the practice of M. Fourneyron, varies from I2D to 1-44D. For turbines of 
 large diameter, 6 feet and upwards, the first of these coefficients is taken, and for smaller diameters, 
 the last. 
 
 The number of channels, of course, also varies as the diameter, but not proportionally. In the rules 
 published by the iuventor, 36 is given as a constant number with the same number of guide-curves on the 
 interior disk ; but in some of the machines of later construction these numbers are reduced. D’Aubuisson 
 mentions turbines which he has examined having as few as 18 channels with from 16 to 9 guide-curves. 
 Jariez gives the following rule for the number :■ — Divide the interior circumference by the height d, and the 
 quotient number which results is the number of channels in the turbine. If this number be comprised 
 between 18 and 24, its half represents the number of fixed guide-curves; if it be greater than 24, thee 
 Yol. II. — 56 
 
WATER-WHEELS. 
 
 882 
 
 ii third of it 'trill be the number of these fixed compartments. It is, however, easy to perceive that this 
 rule must only be a distant approximation ; but even an approximation is better than no rule where 
 theory seems insufficient to determine the question. The number, according to Prof. Ruhlmau, depends 
 principally upon the available quantity of water ; they must be greater as more water is discharged in 
 a given time. In any case, a large number of channels is an advantage, when they are formed of thin 
 sheets, as thereby a greater number of filaments of water act directly upon their surfaces, and not in- 
 directly through a mass of other water interposed. 
 
 We have above, following the rules laid down by M. Fourneyron, giving the depth of the channels as 
 a seventh of the inside diameter of the turbine ; but when the sluice is raised only a small part of this 
 height, as it must be at times when the supply of water is scarce, the effect is not only absolutely less : 
 it is relatively so on account of the water losing a portion of its force in diffusing itself over too much 
 space. 'To avoid this, M. Fourneyron, in some of his last constructed machines, has divided the turbine, 
 as before intimated, horizontally into two or three stages, by means of thin plates of sheet-iron placed 
 in the channels. 
 
 The curvature of the water channels of the turbine 
 and of the guide-curves in the fixed crown, may be 
 determined by the following mode. Describe the in- 
 terior circumference with radius o a = D, found as 
 above directed ; also the external or greatest circum- 
 ference of the turbine with radius o G = l - 4 D. These 
 circumferences being described, draw a h making sin 
 Y 
 
 it a o = From the centre o draw o d, making: with 
 
 2 v ’ ° 
 
 a o an angle doa = dav, and from the point e, where 
 
 0 d cuts the circle representing the tube or pipe 
 through which the spindle of the turbine ascends, 
 take e b parallel to o a ; from b draw b c perpendicu- 
 lar to a d, and from d draw dc perpendicular to e b ; 
 the point c where these two perpendiculars meet will 
 lie the centre of the fixed or guide-curve e dba. 
 
 To find the curve of the vertical diaphragm a I of the turbine, draw ap a tangent to the point a ; and 
 let ap and a h be proportional to the velocities v and V of the turbine and water: -the diagonal a q of 
 the parallelogram constructed upon these two lines will be the direction of the first element of the 
 curve. Prolong a q to G, making a G perpendicular to a L, which is p a prolonged indefinitely, cutting 
 m K the exterior circumference of the turbine-disk. The point I at which the extremity of the curve 
 terminates, is 2-oth of G K. The two extreme points being thus found, the curvature i3 determined as 
 follows : — From the point K as a centre, and with a radius I K, describe the arc of a circle I i , and pro- 
 long indefinitely the right line I K. Measure the line a i, with any scale of equal parts, and divide the 
 number expressing its length by 1 — cos M K L, and the quotient number of this division, taken in units 
 of the same kind as a i, will express the length K M. From this point M draw M L perpendicular tc 
 K L ; divide M L into any number of parts as m, m as many as convenient, and the more the bet- 
 
 ter ; from each of these points draw a straight line passing through the point K, and with the length 
 
 1 M in the compasses mark off equal distances from the points in on their prolongations beyond K. 
 
 aud the points thus marked off will be points in the curve a I, which may accordingly be traced through 
 them. 
 
 * The attention of American engineers was directed to the improved reaction water-wheels in use in 
 France and other countries in Europe, by several articles in the Journal of the Franklin Institute ; and 
 in the year 1843, there appeared in that journal, from the pen of Mr. Elwood Morris, an eminent engi- 
 neer of Pennsylvania, a translation of a French work, entitled “Experiments on Water-Wheels having 
 a Vertical Axis, called Turbines, by Arthur Morin, Captain of Artillery,” etc. In the same journal, 
 Mr. Morris also published an account of a series of experiments, by himself, on two turbines constructed 
 from his own designs, and then operating in the neighborhood of Philadelphia. The experiments on 
 one of these wheels, indicate a useful effect of seventy-five per cent, of the power expended, a result as 
 good as that claimed for the practical effect of the best overshot-wheels. 
 
 BOYDEN’S TURBINE.* In the year 1844, Uriah A. Boyden, Esq., an eminent hydraulic engineer 
 of Massachusetts, designed a turbine of about seventy-five horse-power, for the Picking House of the 
 Appleton Company’s cotton-mill, at Lowell, in Massachusetts, in which wheel, Mr. Boyden introduced 
 several improvements of great value. The performance of the Appleton Company’s turbine, was care- 
 fully ascertained by Mr. Boyden, and its effective power exclusive of that required to carry the wheel 
 itself, a pair of bevel gears, and the horizontal shaft carrying the friction pulley of a Prony dynamom- 
 eter - , was found to be seventy-eight per cent, of the power expended. In the year 1846, Mr. Boyden 
 superintended the construction of three turbines of about one hundred and ninety horse power each, 
 for the same company. By the terms of the contract, Mr. Bovden’s compensation depended upon the 
 performance of the turbines, and it was stipulated that two of them should be tested. The mean max- 
 imum effective power of the two turbines tested, was eighty-eight per cent, of the power of the water 
 expended. 
 
 The principal points in which one of them differs from the constructions of Fourneyron are as follows. 
 
 The wooden flume, conducting the water immediately to the turbine, is in the form of an inverted 
 truncated cone, the water being introduced into the upper part of the cone, on one side of the axis of 
 the cone (which coincides with the axis of the turbine) in such a manner, that the water, as it descends 
 
 3613. 
 
 * Lowell Hydraulic Experiments. J. B. Francis. 
 
WATER-WHEELS. 
 
 883 
 
 in the cone, has a gradually increasing velocity, and a spiral motion ; the horizontal component of the 
 spiral motion being in the direction of the motion of the wheel. This horizontal motion is derived from 
 the necessary velocity with which the water enters the truncated cone ; and the arrangement is such 
 that, if perfectly proportioned, there would be no loss of power between the nearly still water in the 
 principal penstock and the guides or leading curves near the wheel, except from the friction of the water 
 against the walls of the passages. 
 
 The guides or leading curves are not perpendicular, but a little inclined backwards from the direction 
 of the motion of the wheel, so that the water, descending with a spiral motion, meets only the edges of 
 the guides. This leaning of the guides has also another valuable effect. ; when the regulating gate is 
 raised only a small part of the height of the wheel, the guides do not completely fulfil their office of di- 
 recting the water, the water entering the wheel more nearly in the direction of the radius, than when 
 the gate is fully raised ; by leaning the guides, it will be seen that the ends of the guides, near the 
 wheel, are inclined, the bottom part standing further forward, and operating more efficiently in directing 
 the water, when the gate is partially raised, than if the guides were perpendicular. 
 
 In Fourneyron’s constructions, a garniture is attached to the regulating gate, and moves with it, for 
 the purpose of diminishing the contraction ; this, considered apart from the mechanical difficulties, is 
 probably the best arrangement. In the Appleton Turbine, the garniture is attached to the guides, 
 the gate (at least the lower part of it) being a simple thin cylinder. By this arrangement, the gate 
 meets with much less obstruction to its motion than in the old arrangement, unless the parts are so loose- 
 ly fitted as to be objectionable ; and it is believed that the coefficient of effect, for a partial gate, is pro- 
 portionally as good as under the old arrangement. 
 
 On the outside of the wheel is fitted an apparatus, named by Mr. Boyden the diffuser. The object 
 of this extremely interesting invention, is to render useful a pai-t of the power otherwise entirely lost, in 
 consequence of the water leaving the wheel with considerable velocity. It consists, essentially, of two 
 stationary rings or discs, placed concentrically with the wheel, having an interior diameter a very little 
 larger than the exterior diameter of the wheel ; and an exterior diameter equal to about twice that of 
 the wheel ; the height between the discs, at their exterior circumference, is a very little greater than 
 that of the orifices in the exterior circumference of the wheel, and at the exterior circumference of the 
 discs, the height between them is about twice as great as at the interior circumference ; the form of 
 the surfaces connecting the interior and exterior circumferences of the discs, is gently rounded, the first 
 elements of the curves, near the interior circumferences, being nearly horizontal. There is, consequent- 
 ly. included between the two surfaces, an aperture gradually enlarging from the exterior cirumference 
 of the wheel, to the exterior surface of the diffuser. When the regulating gate is raised to its full 
 height, the section, through which the water passes, will be increased by insensible degrees, in the pro- 
 portion of one to four, and if the velocity is uniform in all parts of the diffuser at the same distance 
 from the wheel, the velocity of the water will he diminished in the same proportion; or its velocity on 
 leaving the diffuser, will he one-fourth of that at its entrance. By the doctrine of living forces, the 
 power of the water in passing through the diffuser must, therefore, be diminished to one-sixteenth of the 
 power at its entrance. It is essential to the proper action of the diffuser, that it should be entirely un- 
 der water ; and the power rendered useful by it, is expended in diminishing the pressure against the 
 water issuing from the exterior orifices of the wheel ; and the effect produced, is the same as if the 
 available fall under which, the turbine is acting, is increased a certain amount. The action of the diffu- 
 ser depends upon similar principles to that of diverging conical tubes, which, when of certain propor- 
 tions, it is well known, increase the discharge. Experiments on the same turbine, with and without a 
 diffuser, show a gain in the coefficient of effect due to the latter, of about three per cent. 
 
 Suspending the wheel from the top of the vertical shaft, instead of running it on a step at the bottom. 
 This had been previously attempted, but not with such success as to warrant its general adoption. 
 
 The manner adopted by Mr. Boyden is fully illustrated in the accompanying plates. 
 
 TURBINE WHEEL. Plate VIII. is a vertical section through the centre of a turbine wheel, and 
 the axis of the supply pipe. Plate XI. is a plan of the turbine and wheelpit. Fig. 3810 is a plan of 
 the whole wheel, the guides and garniture. This turbine was constructed for the Tremont Manufactur- 
 ing Co. at Lowell, by Mr. James B Francis, and contains most of Mr. Boyden’s improvements. Its ex- 
 penditure of water, under 13 feet head and fall, is about 139 cubic feet per second, and its ratio of use- 
 ful effect to the power expended, about 79 per cent. 
 
 B, the surface of the water in the wheelpit, represented at the lowest height at which the turbine is 
 intended to operate. C, the masonry of the wheelpit. D, the floor of the wheelpit. To resist the 
 great upward pressure which takes place when the wheelpit is kept dry by pumps, three cast-iron beams 
 are placed across the pit, the ends extending about a foot under the walls on each side ; on these are 
 laid thick planks, which are firmly secured to the cast-iron beams by bolts. To protect the thick plank- 
 ing from being worn out by the constant action of the water, they are covered with a flooring of one 
 inch boards. E, the wrought-iron supply pipe. This is constructed of plate iron three-eighths of an 
 inch thick, riveted together. The supply pipe is furnished with the man hole and ventilating pipe G, 
 and the leak box II, to catch the leakage of the head gate, whenever it is closed for repairs of the 
 wheel. 
 
 The lower end of the supply pipe is formed by the cast-iron curbs III. The curbs are supported 
 from the wheelpit floor by four columns, resting on the cast-iron beam 0 ; the beams N', rest immedi- 
 ately upon the columns, and the curb upon the beams, the latter projecting over the columns far enough 
 for that purpose. The beams N' also act as braces from the wheelpit wall to the curb, and are strongly 
 bolted at each end. 
 
 K, the disc. This is of cast-iron, and is turned smooth on the upper surface, and also on its circum- 
 ference. It is suspended from the upper curb I, by means of the disc pipes M M. The disc carries on 
 its upper surface, thirty-three guides, (fig. 3816,) for the purpose of giving the water entering the wheel 
 
8S 4 WATER-WHEELS. 
 
 --C3 
 
WATER-WHEELS. 
 
 885 
 
 proper directions. They are made of Russian plate iron, one-tenth of an inch in thickness, secured to 
 the disc by tenons, riveted on the under side. The upper corners of the guides, near the wheel, are 
 connected by the garniture L, which is intended to diminish the contraction of the streams entering the 
 wheel, when the regulating gate is fully raised. The garniture is composed of thirty-three pieces of 
 cast-iron, carefully fitted to fill the spaces between the guides ; they are strongly riveted to the guides 
 and to each other. 
 
 The upper flange of the disc pipe is furnished with adjusting screws, by which the weight is support 
 ed upon the upper curb. The escape of water between the upper curb and the upper flange of the disc 
 pipe, is prevented by a band of leather on the outside, which is retained in its place by the wrought- 
 iron ring P. The top of the disc pipe, just below the upper flange, has two wings, fitting into recesses 
 in the top of the curb, to prevent the disc from rotating in the opposite direction to the wheel. 
 
 R, R, the regulating gate. Represented Plate XI. as fully raised. The gate is of cast-iron ; the up- 
 per part of the cylinder is stiffened by a rib, to which are attached three brackets S 'S. To these brack- 
 ets are attached wrought-iron rods, by which the gate is raised or lowered. To one of the rods is at- 
 tached the rack Y. The other two rods are attached by means of links, to the levers T T. The other 
 ends of these levers carry geered arch heads, into which, and into the rack V, work three pinions, W, 
 of equal pitch and size, fastened to the same shaft, so arranged that by the revolution of the pinion 
 shaft, the gate is moved up or down, equally on all sides. The shaft on which the pinions are fastened, 
 is driven by the worm wheel X ; this is driven by the worm a, either by the governor Y, or the hand 
 wheel Z. The shaft on which the worm a is fastened, is furnished with movable couplings, which, when 
 the speed gate is at any intermediate points between its highest and lowest positions, are retained in 
 place by spiral springs ; in either of the extreme positions, the couplings are separated by means of a 
 lever moved by pins in the rack Y ; by this means, both the regulator and hand wheel are prevented 
 from moving the gate in one direction, when the gate has attained either extreme position. If, how- 
 ever, the regulator or hand wheel should be moved in the opposite direction, the couplings would catch, 
 and the gate would he moved. The weight of the gate is counterbalanced by weights attached to the 
 levers T T, and by the intervention of a lever to the rack V. 
 
 b b, the wheel consists of a central plate of cast-iron, and two crowns c c, of the same material to 
 which the buckets are attached. The buckets are forty-four in number, made of Russian plate iron, 
 pj- of an inch in thickness, and are secured to the crowns by grooves cut in the crowns of the exact 
 form of the buckets, and by tenons, entered into the mortises in both crowns, and riveted on the opposite 
 sides. 
 
 d d , the vertical shaft, of wrought-iron, runs upon a series of collars, resting upon corresponding pro- 
 jections in the suspension box e' . The part of the shaft on which the collars are placed, is made sepa- 
 rate from the main shaft, and is pinned to it at f by means of a socket in the top of the main shaft, 
 which receives a corresponding part of the collar piece. The collars are made of cast steel ; they are 
 separately screwed on, and keyed to a wrought-iron spindle. 
 
 The suspension box is made in two parts, to admit of its being taken off and put on the shaft ; it is 
 lined with Babbit metal. It is found that bearings thus lined will carry from fifty to a hundred pounds 
 to the square inch, with every appearance of durability. 
 
 f'f\ the upper and lower bearings, are of cast iron, lined with Babbit metal, adjustable horizontally 
 by means of screws. The suspension box e 1 , rests upon the gimbal g. The gimbal itself is supported 
 on the frame h h by adjusting screws, which give the means of raising and lowering the suspension box, 
 and with it, the vertical shaft and wheel. The lower end of the shaft is fitted with a cast-steel pin i. 
 This is retained in its place by the step, which is made in three parts, and lined with case-hardened 
 wrought-iron. 
 
 The weight of the wheel, upright shaft, and bevel geer, is supported by means of the suspension box 
 e on the frame k, which rests upon the long beams m, reaching across the wheelpit, and supported at 
 the ends by the masonry, and also at intermediate points by the braces n n. 
 
 Mr. Francis deduces the following rules for proportioning turbines: 
 
 The sum of the shortest distances between the buckets, should be equal to the diameter of the wheel. 
 
 The width of the crowns should be four times the shortest distance between the buckets. 
 
 The sum of the shortest distances between the curved guides, taken near the wheel, should he equal 
 to the interior diameter of the wheel. 
 
 The number of buckets is, to a certain extent, arbitrary. As a guide in practice, to he controlled by 
 particular circumstances, and limited to diameters of not less than two feet, the number of buckets 
 should he three times the diameter in feet, plus thirty. The Tremont Turbine is 8£ feet in diameter, 
 and according to the proposed rule, should have fifty-five buckets instead of forty-four. The number 
 of the guides is also to a certain extent arbitraiy; the practice at Lowell has been, usually, to have from 
 a half to three-fourths of the number of buckets. 
 
 As turbines are generally used, a velocity of the interior circumference of the wheel, of about fifty- 
 six per cent, of that due to the fall acting upon the wheel, appears most suitable. 
 
 To lay out the curve of the buckets — 
 
 Referring to fig. 3817, the number of buckets N, having been determined by the preceding rules, set 
 
 IT I) 
 
 off the arc yi — Let u — gh, the shortest distance between the buckets : t the thickness of the 
 
 N 
 
 metal forming the buckets. Make the arc glc = 5 w. Draw the radius o k, intersecting the interior cir- 
 cumference of the wheel at l ; the point l will be the inner extremity of the bucket. Draw the direc- 
 trix Im tangent to the inner circumference of the wheel. Draw the arc o re, with the radius w + t, from 
 i, as a centre ; the other directrix y pi, must be found by trial, the required conditions being, that when 
 the line ml is revolved round to the position gt, the point m being constantly on the directrix g p, and 
 another point at the distance m g = r s, from the extremity of the line describing the bucket, being con- 
 
88G 
 
 WATER-WHEELS. 
 
 ■ •tantly on the directrix m l, the curve described shall just touch the arc n o. A convenient line for a 
 jrst approximation, may be drawn by making the angle 0 y p — 11°. After determining the directrix 
 according to the preceding method, if the angle 0 gp should be greater than 12°, or less than 10°, the 
 length of the arc g h should be changed, to bring the angle within these limits. 
 
 The trace adopted for the corresponding guides is as follows : — The number n having been determined, 
 divide the circle in which the extremities of the guides are found, into n equal parts, v w, w x, the. Put 
 to' for the width between two adjoining guides, and t' for the thickness of the metal forming the guides 
 
 We have by rule =lL. With w as a centre, and the radius w +<', draw the arc y z; and with £ as a 
 n 
 
 centre, and the radius 2(«' +<'), draw the arc a b ' . Through v draw the portion of a circle v c' touching 
 the arcs yz and a b' ; this will be the curve for the essential part of the guide. The remainder of the 
 guide c d', should be drawn tangent to the curve c' v , a convenient radius is one that would cause the 
 curve c 1 d 1 , if continued, to pass through the centre 0. 
 
 Passot’s Turbine , Figs. 3818, 3819, 3820. 
 
 “ Are composed of cylindrical vessels fixed to vertical arbors, and supplied at the circumference 
 with orifices intended for the introduction or ejection of the water. The modification which M. Passot 
 has introduced into the old reacting wheels, and which he claims as his invention, consists of having 
 suppressed or got rid of the internal partitions, and reduced the old wheels to their only true essential 
 elements — a motive cylinder to contain the motive fluid, with surfaces to receive its action, and corres- 
 ponding orifices for discharge. The surfaces and the orifices are exactly included between two concen- 
 tric circumferences ; that is to say, that he carefully retrenches all other surface, or projection, capable 
 of impressing the water with the angular movement of the wheel before having reached the parts 
 destined to receive its action, as well as the orifices of discharge. “ I form the new wheel,” says M 
 Passot, “ simply by placing either in the interior or exterior of a cylindrical drum, according as I want 
 the pressure of the fluid to be exerted on the interior or exterior curved vanes in the arc of a circle, 
 such as abed, Figs. 3819 and 3820 ; then I make orifices of discharge, by removing from these vanes 
 and from the cylinder the part in form of a wedge, a b d, and the motion is effected by virtue of the 
 pressure on the faces c d, c' d' , c" d" . 
 
 “ While the machine is very simple, its properties are very remarkable. When the wheel turns 
 without load or work, under a given difference of level or fall, its vanes take exactly the theoretical 
 velocity due to the fall. It is no longer the same when in any manner the form of the new wheel is 
 altered so as to approach those formerly known; all partitions, projections, and asperities which are 
 either within or without two concentric circumferences, considerably diminish the theoretic velocity of 
 rotation due to the fall, on account of the continual shock of these bodies in motion against the water in 
 repose. Then it is not surprising if the useful effect of reacting wheels, when experimented upon, has 
 never risen above 50 per cent. ; that is to say, about the rate of breast-wheels of the usual varieties. 
 
 “ The expenditure of water in Fig. 3820 with the internal action, is sensibly independent of the 
 greater or less reaction of the wheel. In Fig. 3819, with external action, this cannot take place on ac- 
 count of the counter-pressure arising from the formation of an eddy in the interior ; but this counter 
 ;r assure is. however, much less than might be supposed. I have demonstrated that when a fluid forms 
 
 3S19. 
 
 an eddv in the interior of a cylinder, the effects of the centrifugal force show themselves differently 
 according to the different inclinations of the projections or orifices made on the . influ 
 
 “ In Fig. 3819 the orifices are disposed in the direction in which the centufugal foice ca 
 
WATER-WHEELS. 
 
 8S7 
 
 snce the expenditure of water. Thus the coefficient of theoretical expenditure due to the work, during 
 the experiments on the turbine which I constructed at Bourges, has been found very little different front 
 that which agrees with the openings of ordinary sluices disposed so as to avoid contractions on three of 
 the sides. The wheel which turned in work, with about half the velocity due to the fall, and the co- 
 efficient, was 070 to 0'79.” 
 
 M. Poncelet, adopting an arrangement the reverse of that of M. Fourneyron, has proposed a system 
 of turbines of the nature of the horizontal wheels used in the centre and south of France. The water 
 enters by a spout placed on the outside, stretches the vanes, and is discharged by two openings made 
 towards the centre. M. Cardelhac has constructed at Toulouse turbines on this plan ; and Messrs. 
 Mellet and Sarrus, of Lodeve, have exhibited one with the same arrangement. The principal part ol 
 their turbines consists in a case of particular form, provided with three openings, of which one is for 
 the water to enter, and the two others to allow it to escape after its action on the wheel. In conse- 
 quence of the spiral form of this casing, the water arrives on the wheel placed in the interior without 
 any shock, and with a velocity due to half the height of the fall. Each of these veins or streams of 
 water acts at the same distance from the axis, as if it were isolated and independent of the other. Its 
 velocity is transformed into pressure by insensible degrees, and without any loss of power. 
 
 Whitelaw s reaction-wheel — Figs. 3814 to 3821. — The principle of this machine has been already ex- 
 plained, it therefore only remains in this place to indicate briefly the practical details and features of 
 the construction. In this latter respect it is a much simpler machine than that above described ; but 
 still its efficiency. depends in nearly an equal degree upon a correct appreciation of the principles in- 
 volved in its modus operandi. The merely technical details have already been pretty fully pointed 
 out in describing the figures enumerated above, but it may be necessary to indicate the rules employed 
 in assimilating these to the conditions furnished by the particular circumstances of the individual case. 
 
 As in all other hydraulic machines, the data necessary to be assigned as the basis of any calculation 
 of the size and angular velocity of the reaction-wheel, are the values of H and Q, that is, the height of 
 fall under which it is intended to act, and the volume of w T ater to be used. We have before seen that 
 if the water in the arms of the machine experienced no increase of pressure from centrifugal force, 
 the discharge assigned by theory is expressed by S 2 cj H ; but in consequence of the centrifugal 
 force produced by the rotation of the machine about its axis, this quantity will be increased to 
 
 S\/2pII-f-i' 2 (l — ■ But we know from experiment that in consequence of frictional disturb- 
 
 ance of the fluid in passing through the apparatus, the real quantity discharged is uniformly less than 
 that assigned by theory, and that the reduction depends upon conditions which to some extent are 
 within the control of the mechanician. On this subject we quote, with slight modification,' from a paper 
 read by Mr. W. M. Buchanan before the Philosophical Society of Glasgow (1846) on the theory of this 
 species of machine. After stating the loss of head, observed in his experimental apparatus, by com- 
 paring the actual fall with the quantity of water actually discharged by a machine, of which the jet- 
 orifices were accurately determined, the author assigns, as the sources of that reduction, 
 
 1. The pressure absorbed by the friction of the water in passing through the supply-pipe. This he 
 regards as a known quantity, which is expressed in character and amount by 
 
 tt 2 
 
 2 ? 
 
 in which C denotes the internal perimeter, A, the cross-sectional area, and L the length of the pipe ; it, 
 the velocity with which the water descends through it, and f an empirical coefficient = - 0035 . If. 
 therefore, S denote the sum of the areas of the orifices, Y the velocity of efflux, and D the diameter ot 
 the pipe, all in feet, this expression may be put under the form 
 
 „ , L S 2 
 f' ' D ‘ A 2 
 
 XI 
 2 1 
 
 2. The loss of head arising from the acceleration of the water in passing from the supply-pipe into 
 ilie interior of the machine through the water-joint neck, formed by the mouth-piece and central open- 
 ing, and which is commonly less in diameter than the supply-pipe, as shown in Fig. 3818. This he 
 expresses by the formula 
 
 » 
 
 A ,1 
 
 Ay 
 
 in which A ;/ is the area of the central opening, and u the velocity of the water passing through it : m 
 a coefficient determined from experiment to be =-9378. 
 
 3. The small loss of head resulting from the resistance encountered by the water in traversing the 
 arms of the machine, which he expresses by 
 
 8/.S 2 — A-d* = y— . 
 
 J 2, /JO Ajjj 7 2 a 
 
 in which C, and A lu are respectively the transverse perimeter and area of the channels at a distance * 
 from their origin. 
 
 4. The loss resulting from what is called the contracted vein. Although the volume of water dis- 
 charged by any orifice under a given head-pressure is invariably proportional to the area of that orifice 
 and the square root of the head, the actual quantity is found to depend much upon the form of the 
 orifice through which it issues. If the fluid be confined in a vessel of thin material, and the orifice be 
 
888 
 
 WATER- WHEELS. 
 
 simply a hole pierced in its side, the discharge in cubic feet per second -will be nearly expressed by 
 W2 g H, the area of the orifice being a. If the jet from an orifice of this kind be closely observed, 
 it will be perceived to converge through a short distance from its origin, forming, when the orifice is 
 circular, a conoid, of which the area of the least section is gths of the area of the orifice. If advantage 
 
 oe taken of this circumstance to apply an ajutage to the orifice of the form assumed by the jet, tfte 
 discharge will be found to approximate very closely to that assigned by the theoretical formula. 
 
 This difference of discharge in the two kinds of aperture is usually ascribed to the inclined directions 
 which the molecules of the fluid assume previous to their exit, and which they tend to retain after pass- 
 ing the thin parietes of the simple orifice. For greater clearness, let us assume that the aperture is 
 
890 
 
 WATER- WHEELS. 
 
 horizontal, circular, and of small area in comparison with the area of the containing vessel ; under these 
 conditions a large portion of the fluid will be put in motion, and will slowly approach the orifice during 
 the efflux, in the form of an inverted cone, of which the orifice is the apex. The particles, as they come 
 opposite to the orifice, are therefore impressed with motions converging to an axis ; but these motions, 
 in consequence of the mutual cohesion of the particles, must tend to a common velocity in that axis ; 
 and the length of the external conoid will express the time in which the oblique motions are converted 
 into motions parallel to the axis of the jet. It is therefore only at the point of least section that the 
 molecules of fluid have attained the effective velocity due to the head under which they issue ; and it is 
 therefore only in reference to that point that the hydraulic pressure of the jet is equal to a column of 
 the fluid of double the actual head. By adopting an ajutage to the orifice of the shape indicated, the 
 oblique motions of the particles are corrected in passing through it, and reduced to parallelism with the 
 axis at the moment of efflux into the atmosphere. There still, however, remains to depreciate the dis- 
 charge assigned by the formula q—a ^/2 g H, the imperfections of wormanship in the construction, and 
 the adhesion of the fluid to the perimeter of the ajutage, with possibly a slight atmospheric influence 
 not yet defined. But assuming the ajutage to be made with all possible care, both as to form and 
 finish, if we call the area of the orifice 1000, that of the contracted vein will be 915 ; and these num- 
 bers taken inversely will express the velocity of the jet at the two points measured by the discharge. 
 The value of q for an orifice of this form will therefore be 
 
 y = -975 a ^/2 g H, 
 
 showing a loss of head-pressure, as measured by the discharge, of 
 
 U 2 
 
 (1 — -975 2 ) — = -049375 H 
 2 9 
 
 when IT = ^2^11 the theoretical velocity due to the head H. And generally, if Y be the actual ve- 
 
 V 
 
 locity of efflux, and k the practical coefficient of discharge for any orifice, so that U =— , the head- 
 
 /I \ V 2 V 2 
 
 pressure not realized in the measure of q, will be ( — 1} — —S — . And the pressure not realized 
 
 /2p 2p 
 
 in the measure of the reaction, will be expressed by 
 
 Sin 
 
 / 1 \ 
 
 (l 2_ V 2 
 
 V 2 
 
 9' 
 
 V 2 
 
 in which <p denotes the mean angle formed by the filaments of water of the jet with the axis. 
 
 But betwixt this the least contraction of the fluid vein, and that which takes place when the orifice is 
 formed in a thin plate, we may evidently have a series of any number of terms expressing successive 
 degrees of approximation of the ajutage to the theoretical form of least contraction. This is obvious, as 
 regards the discharge from a fixed ajutage ; and it is equally obvious, that if an ajutage be constructed 
 to fulfil the conditions of least contraction when the vessel is at rest, it will no longer answer that con- 
 dition when it moves in the line of the jet with any given velocity. If its motion be in the direction of 
 the jet, its length will manifestly be virtually increased, and the contraction will approach to that of a 
 jet issuing from a parallel pipe, the coefficient for which is -8 ; and if the movement be in the contrary 
 direction, the length of the ajutage will be in effect diminished, and the contraction will approach that 
 from an orifice in a thin plate. This last is the actual case which falls to be considered in the reaction 
 machine; the ajutages have a determinate velocity, in an opposite direction to that in which the fluid 
 issues, and accordingly have their length virtually reduced. This must necessarily be provided against 
 in the construction of the machine, and a length and form of the ajutages determined, which shall ex- 
 actly correspond, at the given angular velocity of the machine, to the proper dimensions at which, if 
 stationary, they would yield their maximum discharge. This is a problem which requires to be resolved 
 for every machine. 
 
 It may, however, be stated as a general rule, that the contraction of the channels towards the orifices 
 is half of that which would give the maximum discharge if the machine was at rest, and may therefore 
 be taken at 7°. 
 
 If to these absorbing influences we add c - — , comprehending the loss of atmospheric pressure due to 
 
 the head H, and the effect of the cohesion of the water to the perimeter of the orifices, (not valued,) we 
 shall have as the total calculated loss of head-pressure, 
 
 (a + ff + y + ^ + e)— , 
 
 and putting a-f/3-fy-)-(l-|-£ = K, we shall have as the velocity of efflux, taking the formula of p. 792, 
 
 TPfSnAh + e(i-A). 
 
 In those machines constructed according to the proportions usually adopted by the makers, tha 
 quantity - — does not differ sensibly in ordinary cases from 0‘94 ; and it has been stated that 
 
 V 1 + K 
 
 It = 2-5 r ; if, therefore, we substitute these numbers in this formula, it is reduced to the following : 
 0-94 V 2 g H A\s4 — 7-5 y/ H + i e 2 = V 
 
WATER-WHEELS. 
 
 891 
 
 A.nd multiplying this last expression by 60 times the area of the two orifices, (in feet,) we shall have, aj 
 
 the quantity of water discharged in a minute, 450 S 
 
 II -f- — v 1 cubic feet = Q. 
 
 We have already found as the measure of the effect of the machine — (V — v)v; if, therefore, in this 
 
 9 
 
 expression we substitute the actual value of Y found above, we shall have 
 
 But, in practice, the velocity v of the machine is taken equal to 8 ,/ H. If, therefore, we substitute 
 this value in that found for E, and put for w its equivalent 62 5 q, and for g its value 32'2, we shall have 
 
 E = 50 q H very nearly. 
 
 Or, taking the quantity of water expended in a minute, and expressing E in units of horse-power, 
 we have 
 
 e = «5, 
 
 660 
 
 which is this rule : Multiply the quantity of water expended in a minute by the given height of fall, and 
 divide the product by 660 : the resulting quotient will express the effect in units of horse-power, (the 
 horse-power being 33,000 lbs. raised through a height of 1 foot in a minute.) 
 
 This rule shows that the machine ought to yield, in practice, an effect of 79} per cent, of the power 
 expended, independently of the partial losses of head above enumerated, taking the fall from the mid- 
 dle of the depth of the machine to the surface of the water in the reservoir. 
 
 Height of fall. 
 
 II. 
 
 Quantity of wa- 
 ter expended in 
 1 minute. 
 
 Q. 
 
 Weight on the 
 arms of the fric- 
 tion brake. 
 
 V' 
 
 Velocity in the 
 circle of the 
 brake. 
 
 V. 
 
 Percentage cf 
 effect. 
 
 W H 
 
 100 . 
 
 pv 
 
 Diameter of 
 model. 
 
 Feet. 
 
 9’335 
 
 Cubic feet. 
 10169 
 
 Oz. 
 
 9 
 
 Feet. 
 
 7910 
 
 75-212 
 
 
 10-520 
 
 11-530 
 
 9} 
 
 9510 
 
 76-664 
 
 •* 
 
 10'355 
 
 10-360 
 
 10} 
 
 7820 
 
 74-933 
 
 
 10-210 
 
 10-330 
 
 10 
 
 7820 
 
 74-433 
 
 p 
 
 10-040 
 
 10-338 
 
 “ 
 
 7900 
 
 76-333 
 
 9-735 
 
 10-250 
 
 9| 
 
 7820 
 
 76-630 
 
 § 
 
 9'575 
 
 9-790 
 
 
 7330 
 
 76-460 
 
 9-390 
 
 9-305 
 
 “ 
 
 6690 
 
 74-868 
 
 1 
 
 10-335 
 
 11-090 
 
 “ 
 
 8960 
 
 76-440 
 
 ft 
 
 10-165 
 
 11-010 
 
 “ 
 
 8840 
 
 77-236 
 
 2 
 
 9-830 
 
 10-350 
 
 “ 
 
 8030 
 
 77-173 
 
 r-’ 
 
 9-680 
 
 10-080 
 
 <( 
 
 8420 
 
 77-887 
 
 
 10-010 
 
 10-740 
 
 “ 
 
 85S0 
 
 78-040 
 
 L~- 
 
 10-700 
 
 13-69 
 
 to 
 
 5340 
 
 74-945 
 
 OJ* 
 
 10-545 
 
 13-44 
 
 “ 
 
 5240 
 
 76-015 * 
 
 2, 
 
 10-415 
 
 13-05 
 
 u 
 
 5040 
 
 76-237 
 
 
 10-250 
 
 12-79 
 
 u 
 
 4900 
 
 76-845 
 
 
 10-130 
 
 12-73 
 
 “ 
 
 4870 
 
 77-644 
 
 £ 
 
 9-980 
 
 12-48 
 
 “ 
 
 4630 
 
 76-425 
 
 C 
 
 O 
 
 9-820 
 
 12-44 
 
 “ 
 
 4500 
 
 75-745 
 
 
 9 660 
 
 11-92 
 
 a 
 
 4280 
 
 76-420 
 
 i 
 
 9-840 
 
 12-33 
 
 20} 
 
 4600 
 
 77-000 
 
 £ 
 
 9-700 
 
 12-45 
 
 19} 
 
 4750 
 
 77-910 
 
 
 9-950 
 
 12-40 
 
 20} 
 
 4700 
 
 78-320 
 
 
 10-270 
 
 12-68 
 
 21 
 
 4740 
 
 76-660 
 
 
 10-460 
 
 12-47 
 
 22 
 
 4540 
 
 76-800 
 
 
 8-05 
 
 Lbs. 
 
 562-32 
 
 14 
 
 37620 
 
 72-69 
 
 
 “ 
 
 560-33 
 
 
 3685-4 
 
 74-03 
 
 “ 
 
 558-75 
 
 15 
 
 3647-3 
 
 75-84 
 
 2 0 
 
 
 553-61 
 
 154 
 
 34S8-5 
 
 7601 
 
 (( 
 
 548-36 
 
 16 
 
 3380-4 
 
 76-56 
 
 Jl 
 
 “ 
 
 53000 
 
 164 
 
 3202-5 
 
 77-39 
 
 ‘ 4 
 
 514-25 
 
 17 
 
 2973-7 
 
 76-31 
 
 
 The preceding table of experiments, upon three model machines, will show that this high percentage 
 n effect is attainable. In the experiments with the first models, the fall was variable, aud the proper 
 relocity of the machine was, therefore, in no case strictly attained. The correct velocity was not at- 
 
892 
 
 WATER-WHEELS. 
 
 tained in the third set of experiments, although the fall was constant, in consequence of the successive 
 variations of load being too great. The maximum of effect is therefore not obtained in any of the re- 
 sults given, but some of the results approach it very closely. 
 
 The mode of performing the experiments was nearly the same throughout. The load was applied 
 upon the equal arms of a friction brake of T59155 feet radius, (as nearly as could be measured,) so that 
 its circle was exactly 10 feet. The revolutions of the machine were ascertained by a counter worked 
 by a screw cut on its vertical spindle ; and the water discharged was received into a cistern, of which 
 the dimensions were accurately determined. The circle of the arms of the brake at the points where 
 the weight was attached being 10 feet, the numbers in the column stating the velocity in that circle 
 being divided by 10, the quotient will, of course, show the number of revolutions made by the machine 
 in the unit of time, 1 minute. 
 
 The constructive rules, published by Mr. Wliitelaw in the Artizan for Nov. 1845, are as follows, the 
 height of fall and the quantity of water furnished in a minute being known : 
 
 A horse-power being taken at 33,000 lbs. raised one foot in a minute, this will be represented by 
 43,421 lbs. of w T ater per minute, with a fall of one foot, supposing the machine to realize only *76 per 
 cent, of the power expended; and the weight of a cubic foot of water being taken at 62,321 lbs., the 
 c-quivalent of 43,421 lbs. will be 696'7 3 cubic feet. Taking Q and H as before, the quantity of water 
 furnished in a minute and height through which it descends, we have as the value of E in units of horse- 
 power, 
 
 69673 
 
 From this the dimensions of the principal parts and the velocity of the machine are determined, as 
 stated in the following expressions — it being understood that the machine has two , and only two jet 
 orifices, and these so formed as not to cause the issuing jets to contract more than in the proportion of 
 97 to 100 after the fluid has left the orifices. 
 
 Width of each discharging orifice ■ 
 
 V 7 
 
 135 E 
 
 1000 Hy/H ' 
 
 Width of each arm of machine = 4 w, = w„ 
 Diameter of the machine = 50 w, = d, 
 Diameter of central opening = 10 w, = o n 
 
 Number of revolutions in a minute _ 
 
 All these rules, except the last, may be departed from with impunity ; but it is impossible to enumer- 
 ate the circumstances and conditions under which modifications may be safely introduced, and where 
 they would be prejudicial. These can only be appreciated by practice and a close investigation of the 
 action of the machine. The rules are, however, safe within a wide range of fall — in fact, for all ordi- 
 nary cases. 
 
 Comparison of the different species of wheels . — -From what we have seen of the different conditions 
 necessary to produce the maximum effect, it is evident that we ought not to be indifferent to the kind 
 of wheel to be adopted in any particular case. The wheel ought especially to be adapted as far as 
 possible, not only to the height of fall and quantity of water to be employed, but also to the kind ot 
 machinery which it is intended to propel. If the motion required be slow, and especially if it be besides 
 irregular, a vertical wheel, of large diameter and considerable weight, will in general be the most sat 
 isfactory. On the cijptrary, where a high velocity is required, a horizontal wheel will be the most 
 economical. The undershot-wheel is only commendable in cases where no other is applicable, on ac- 
 count of the lowness of the fall and large supply of water. It has the advantage, however, of being 
 constructed at comparatively small cost, and if the run of the water be considerable, its velocity will 
 be proportionally high in order that it may yield its maximum effect. Its great inconvenience is the 
 emallness of that effect, which is in part remedied by employing the arrangement recommended by M. 
 Poncelet now extensively adopted on the continent. This may be made to yield an effect of 50 to 60 
 per cent, of that of the water, when the head of water does ndt exceed 4|- feet. It also takes compara- 
 tively a high velocity, and it is to be kept in mind that the higher the velocity of any wheel of this 
 species, the less will be its breadth, size of sluice, arc, and other parts influenced by the volume ot 
 water. It will, moreover, continue to work in backwater until the levels before and behind approach 
 equality, and is therefore particularly fitted for level districts subject to inundations. It is, however, 
 liable to this inconvenience, that its velocity cannot deviate sensibly from that at which it yields its 
 maximum effect without losing greatly in power. 
 
 From falls from 4 to 7 feet, the breast-wheel with radial floats inclosed in an arc may be employed 
 with advantage. If well constructed, and the arc be accurately fitted, to prevent waste of water, this 
 species of wheel is capable of yielding from 60 to 70 per cent, of the power of the water expended. It 
 may besides deviate very considerably from the correct velocity without losing much in effect ; but it 
 is to be observed that this velocity ought never to be very high. This species of wheel is therefore 
 particularly applicable in cases where the ultimate velocity of the machinery impelled is low ; but it 
 lies under the disadvantage that, on account of the slowness of its motion, its breadth must be great, 
 and all its constructive details conformably large and heavy. It is, besides, not well suited for situa- 
 tions subject to backwater, which very speedily brings it to rest. The bucket-wheel is applicable for 
 higher falls and smaller supplies of water. It has all the advantages of the breast-wheel, with some 
 of its defects. It may have a velocity varying from 3 feet a second to 7 feet ; and adopting this highei 
 speed, and allowing the buckets to be half filled with water, its expeDse will be greatly lessened 
 
TABLE OF THE PROPORTIONS OF WATER-WHEELS CONSTRUCTED BY MR. WILLIAM FAIRBAIRN, OF MANCHESTER. 
 
 WATER-WHEELS 
 
 89c 
 
 a o 
 
 o 
 
 o 
 
 
 
 © 
 
 
 
 
 
 
 
 
 
 
 
 
 00 
 
 
 
 Cl 
 
 £* O 
 
 CO 
 
 
 
 
 rH 
 
 
 
 
 
 
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 Note. — M r. Fairbairn’s maximum velocity of the periphery of the wheel is about 7 feet per second for a fall of 5 or f» feet, and his minimum velocity from 2£ to 3 feet for a fall of 40 to 45 feet. 
 
894 
 
 WATER-WHEELS. 
 
 When the fall is high, 18 feet and upwards, it is not common to provide any arc to economize the wa- 
 ter at the lower part of the revolution ; and when the buckets are properly formed, an arc is not greatly 
 wanted. But in general cases the buckets are formed without much attention seemingly to the func- 
 tions which they are intended to perform, and, accordingly, a large waste of power is incurred which 
 an arc would go for to prevent. 
 
 The inconvenience of the bucket-wheel is the low rate of its maximum speed where high working 
 velocities are required. This occasions the multiplication of intermediate geering with all its concomi- 
 tant evils. It is applicable, we have said, to high falls ; but this has its limits. To obtain the full 
 value of the water, the diameter must increase as the fall, and the dimensions and weight assume cor- 
 responding proportions. The construction, accordingly, becomes expensive in a high degree. 
 
 The preceding table of the proportions of wheels of this class, constructed by Mr. William Fairbairn, 
 of Manchester, will be useful. 
 
 When the height of foil exceeds that for which it would be judicious to attempt to construct a bucket- 
 wheel, it is then necessary to have recourse to one or other of the horizontal wheels described — namely, 
 the turbine of M. Fourneyron, or the reaction-wheel of Mr. Whitelaw. The first of these may be made 
 f o yield an effect of about 50 per cent, of value of the water even on very low falls, and when immersed 
 in tail- water; and about 70 per cent, on higher falls. The letter has also been made for situations in 
 which it was intended to work occasionally in backwater, and with very considerable success ; and, for 
 high falls, we have seen that it is capable- of yielding an effect at least equal to the bucket-wheel. It 
 has advantage of the turbine in being less expensive, much more simple, and, we believe, is essentially 
 more effective, on account of there being less loss of vis viva of the fluid in passing through the ma- 
 chine. Both have the advantage of being applicable to falls of any height, and of moving at velocities 
 differing widely from that at which they yield their maximum, without much loss of effect. On low 
 falls they have, what is generally reckoned, an advantage ; they give immediately a comparatively 
 high velocity which, in the case of cotton factories and the like, allows much heavy geering to be dis- 
 pensed with. They have also a further very marked advantage in the little space which they occupy 
 Several reaction-wheels, of 50 horse-power and upwards, might be referred to, placed in situations 
 where, it may be said, they literally occupy no room, being situated in a small pit under the floors of 
 the factories to which they furnish the motive power. In cases where the fall is very high — and both 
 the turbine and reaction-wheel have been applied to falls which could not have been employed on 
 wheels of the common kind — the high speed becomes an inconvenience, causing the use of intermediate 
 geering for the purpose of reducing it. This can be remedied, to a certain extent, by increasing the 
 diameter of the machine ; but, when it is desired to take advantage of falls of 100 feet and upwards, 
 perhaps some little inconvenience may be submitted to without reluctance. 
 
 There remains to be exhibited the turbine of Jonval, now being introduced in this country extensively. 
 
 Jonval’s Turbine , as built by E. Geyelin , Hydraulic Engineer, Philadelphia. — The Jonval turbine 
 was invented and patented in France a few years since, by a French gentleman whose name it bears. 
 
 The first turbine of this species, made by Messrs. Andre Koechlin & Co., was erected and put in 
 operation in a large paper mill at Pont d’Aspach, in the vicinity of Mulhouse, upon which a committee 
 of the Societe Industrielle de Mulhouse experimented, and reported the following tables of the results. 
 
 The experiments were made with the friction brake of Prony. 
 
 Table of experiments with the Friction Brake, made on the Turbine of Pont d’Aspach, and reported by 
 Mr. Amede Riedek, Member of the Committee of the Industrial Society of Mulhouse. 
 
 Number of the Experi- 
 ments. 
 
 Depth of the discharge 
 of water, through an 
 overflow of 3-200 m. 
 wide* 
 
 Weight of water in 
 kilogrammes expended 
 per second. 
 
 Height of the fall in 
 metres. 
 
 Theoretic pow- 
 er of the Motor. 
 
 1 
 
 i Weight on the trie- 1 
 1 lion brake in kilo- 
 grammes. 
 
 Number of revolutions 
 of the Turbine. 
 
 Ti O 
 
 lli 
 
 o ZZ — 
 
 Pel 
 
 =!i 
 
 5 ” * 
 
 Si © <D 
 
 2 = -2 
 z'oi 
 
 1 Velocity which the 
 1 point of suspension of 
 the resistance took in 
 one second. 
 
 Effective power 
 of the Motor. 
 
 1 
 o . 
 
 II 
 
 | S 
 
 Kilog. lifted 1 
 metre high in 
 one second. 
 
 1 
 
 NumbV of horses 
 of 75 kilog. 
 
 ■".S 
 
 ~ o 
 
 JM 
 
 *i§ 
 
 Is 
 
 JO 
 
 So 
 
 ■z 
 
 
 
 
 m. 
 
 
 
 
 
 
 
 
 
 
 i 
 
 0-187 
 
 439 
 
 2-87 
 
 1-259 
 
 16-72 
 
 7000 
 
 76-00 
 
 38-00 
 
 12-229 
 
 856 
 
 9-24 
 
 56 
 
 2 
 
 0-190 
 
 447 
 
 2-87 
 
 1-282 
 
 17-10 
 
 65-00 
 
 96-00 
 
 48-00 
 
 15-448 
 
 1004 
 
 14-72 
 
 86 
 
 3 
 
 0195 
 
 403 
 
 2-90 
 
 1-351 
 
 18-03 
 
 57-00 
 
 1-2400 
 
 62-00 
 
 19*94 
 
 1136 
 
 15-15 
 
 84 
 
 4 
 
 0-195 
 
 4G3 
 
 2" 82 
 
 1-305 
 
 17-47 
 
 47-00 
 
 134-00 
 
 07-00 
 
 21-56 
 
 1013 
 
 13-50 
 
 77 
 
 5 
 
 0-195 
 
 403 
 
 2-71 
 
 1-254 
 
 16-73 
 
 37-00 
 
 164-00 
 
 82-00 
 
 26-39 
 
 976 
 
 1302 
 
 77 
 
 6 
 
 0198 
 
 473 
 
 2-95 
 
 1-399 
 
 18-05 
 
 35-00 
 
 178-00 
 
 80-00 
 
 28-64 
 
 1002 
 
 13-36 
 
 72 
 
 1 
 
 0-239 
 
 039 
 
 2-78 
 
 1-770 
 
 23-68 
 
 89-80 
 
 84-00 
 
 42*00 
 
 13 51 
 
 1213 
 
 16-17 
 
 68 
 
 2 
 
 0-243 
 
 054 
 
 2-78 
 
 1-818 
 
 24-24 
 
 67-25 
 
 124-00 
 
 62-00 
 
 19-94 
 
 1341 
 
 17-85 
 
 73 
 
 3 
 
 0-243 
 
 054 
 
 2-78 
 
 1-818 
 
 24-24 
 
 65-00 
 
 128-00 
 
 64-00 
 
 20-59 
 
 1338 
 
 17-85 
 
 73 
 
 4 
 
 0-230 
 
 041 
 
 2-78 
 
 1-782 
 
 23-76 
 
 67-25 
 
 128-00 
 
 64*00 
 
 20-59 
 
 1385 
 
 18-47 
 
 77 
 
 5 
 
 0-225 
 
 581 
 
 2-78 
 
 1-618 
 
 21-57 
 
 52-00 
 
 134-00 
 
 07-00 
 
 21-56 
 
 1421 
 
 14-95 
 
 69 
 
 7 
 
 0-245 
 
 069 
 
 2-78 
 
 1-859 
 
 24-78 
 
 60-00 
 
 142-00 
 
 71-00 
 
 22-85 
 
 1371 
 
 18-28 
 
 73 
 
 8 
 
 0245 
 
 009 
 
 2-78 
 
 1-859 
 
 24*78 
 
 57-25 
 
 144-00 
 
 72*00 
 
 2315 
 
 1326 
 
 17-68 
 
 71 
 
 9 
 
 0-248 
 
 078 
 
 2-78 
 
 1-884 
 
 2513 
 
 50-00 
 
 164-00 
 
 82-00 
 
 26-39 
 
 1319 
 
 17-59 
 
 70 
 
 General Observations. — The metre is 3 feet 3 and 1-8 inches. 
 
 It will be observed here, that only a very strong change in the speed will alter the percentage 
 of the wheel. The large wheel was in bad condition, as the guide-wheel rested on the turbine and 
 created friction. 
 
TABLE OF EXPERIMENTS, made 6?/ Mr. Theodore Bippert, on the Turbines of Messrs. Geigy, of Steinen. Duchy of Baden, (These Turbines ucre improved 
 
 in the curves of the wheels.) 
 
 WATER-WHEELS. 
 
 895 
 
 General Remarks. 
 
 The numbers 5 and 6, 
 experiments on the large 
 Turbine, show that the 
 power can be reduced to 
 one-fifth without greatly 
 diminishing the percent- 
 age 
 
 The coefficient of con- 
 traction used here is 0'40, 
 given by Mr. Poncelet, on 
 overflows discharging 1 in 
 the open air. 
 
 Percentage of the Turbine. 
 
 d 
 
 
 JT- to 
 
 0 0 0)0 
 OD CO op 05 
 O O O O 
 
 
 to to 
 
 to co 04 i— i Jr- O 
 9 a) oo co 9 p- 
 © o © © © © 
 
 Number of horse-power indicated by the 
 brake. 
 
 Ph 
 
 X 
 
 1 
 
 o 
 
 to 
 
 Jr- 
 
 
 O O L— > — 1 
 to p p P 
 05 05 05 
 
 
 04 c© to co a 
 
 CO J- (N H r|i 
 
 O O O O 04 04 
 
 Weight lifted by the brake. 
 
 pi 
 
 
 t p O O O 
 co cb to o 
 CO CO CO CO 
 
 
 to 
 
 tC^ 10) j ^ 05 
 
 CO 00 CO CO 
 
 Circumferential velocity of the brake per 
 second. 
 
 P-, 
 
 X 
 
 o 
 
 > 
 
 60 
 
 
 05 tO CO c© 
 
 p p co 
 
 05 OH -H 
 1—1 04 04 04 
 
 
 Jr- Jr- —+• co co to 
 H 05 CO CO CQ If 
 04 04 lb rH 05 
 
 04 Ol 04 04 04 i— 1 
 
 Number of revolutions per minute. 
 
 
 
 CO to o o 
 Jo- Jr* co go 
 
 
 CO CO CO to O H4 
 GO 05 05 00 JT- 00 
 
 Circumference of the friction-brake. 
 
 C© 
 
 p 
 ■ cb 
 
 r^i 
 
 II 
 
 o 
 
 s 
 
 16026 
 
 H 
 
 CO 
 
 04 
 
 O - - - - 51 
 
 0 
 
 Number of horse-power. 
 
 MF 
 
 O 
 
 to 
 
 XT- 
 
 
 O O GO H* 
 p p Op 
 rH r— i 04 04 
 
 
 O to Jr r H to 
 
 H 04 rji rji 00 ip 
 04 04 04 04 OO CO 
 
 Height of the fall. 
 
 * 
 
 
 rft JT- 
 
 0999 
 
 
 to 
 
 -H CO 05 05 CO CO 
 p p p O Jr- JT- 
 
 Quantity of water discharged per second. 
 
 • 
 
 O 
 
 o 
 
 II X 
 
 § ° 
 w 
 
 i> 
 
 litres. 
 
 ^ to o co 
 -+< rH to 
 
 to to to to 
 
 litres. 
 
 CO CO CO CO to 05 
 
 to 0 to to CO 
 to to to to 1— 1 r- ( 
 
 Width of the overflow. 
 
 G 
 
 s 
 
 4.09 
 
 
 05 
 
 0 s - - - - 
 
 Theoretical velocity corresponding to the 
 discharge of overflow. 
 
 > 
 
 S ’ 
 
 O to JO o 
 r- Jr- Jr- co 
 
 oo CO oo CO 
 
 g 
 
 0 0 0 0 0 to 
 
 CO CO CO GO CO H 
 00 p 00 p 04 04 
 
 Depth of discharge on the overflow. 
 
 W 
 
 s 
 
 0T780 
 
 OT781 
 
 0T782 
 
 0T800 
 
 £ ’ 
 
 0 0 0 0 0 to 
 cocococooor- 
 --h ' 0 0 
 
 OOOOOO 
 
 Number of Experiments. 
 
 
 
 r-H 04 CO 
 
 
 H 04 CO rH to CO 
 
 Small Turbine. Large Turbine. 
 
 
89G 
 
 WATER-WHEELS. 
 
 H. Amede Rieder, in his report on Jonval’s turbine, enumerates the following as its advantages : 
 
 1st. Its superior mechanical construction and simplicity. 
 
 2d. The great amount of power obtained from the quantity of water used. 
 
 Sd. The regularity of its motion, and the facility of access to it. 
 
 4th. The great practical advantage of its being placed at the top of the fall. 
 
 Experiments have been made on a Jonval turbine at the powder-works of Messrs. E. J. Dupont, by 
 Professor C’resson, and Messrs. Alfred Dupont, Alexis Dupont, S. Y. Merrick, G. Harding, and E. Gey- 
 elin, members of the Franklin Institute. The following is the report, published in the Journal of the 
 Institute, vol. xx., No. 3, 1850. 
 
 The Koechlin turbine. — The hydraulic motor known by this title has just been introduced in this 
 vicinity by Mr. E. Geyelin, at the powder-works of the Messrs. Dupont, near Wilmington, Delaware, and 
 at his request a trial was recently made by certain members of the Institute, to determine the practical 
 coefficient of the wheel. 
 
 The turbine experimented upon is intended to produce I horse-power under a fall of 10. feet, and. to 
 drive the machinery of the new mixing mill at the lower works. It is 21-J inches in diameter, 3^ inches 
 deep, and is to make 190 revolutions per minute, giving 63J revolutions of a horizontal shaft, to which 
 it is geered 3 to 1. To this shaft was attached a Prony dynamometer, whose lever was 7’96 feet long, 
 giving 50 feet circumference. At the time of the experiments, a wooden box, nearly water-tight, was 
 placed in the tail-race, surrounding tile lower part of the wheel. One side of it was cut away, forming 
 a waste-board 3’83 feet wide, over which the water was discharged, and at the same time diminishing 
 the usual head and fall about 9 inches. 
 
 Experiment No. 1. — The distance between the level of water in the penstock or forebay and that of the 
 bottom of the waste-board was 10' 1", and the depth of water flowing over the waste-board 8 J", leaving 
 the actual head, and fall 10' 1 1 ,/ — 8 J" = 9', 4§ = 9 - 34 feet. By Morin’s formula, {Aide Memoire, p. 37,) 
 Q = m L h y/'2 z h ; Q being discharge per second, m the constant, which for -74 depth = '383, L = width 
 of waste-board, = 3-83 feet, and h — depth of water upon it, =-74. Then in this case Q = '383 X 
 3’88 X '74 y/ 04 X '74 =7'468 cubic feet, and the theoretical power due to the water was 7'468 X 62'5 
 X 9'34 X 60 = 261,537 lbs. raised 1 foot per minute = 7'92 horse-power. 
 
 It was found that at 63 revolutions per minute of the horizontal shaft, 63 pounds balanced the lever 
 Hence the power developed by the wheel was 63 X 63 X 50 = 198,450 lbs. = 6'014 horse-power. 
 
 Experiment No. 2. — The gates from the head-race were so far closed as to reduce the head 1 foot, 
 and maintain it at that level during the experiment. The depth of water on waste-board was 8J ,/ , so 
 that the head and fall was 9'T" — 8 J" = 8'-4§" = 8'41 feet. Therefore, by the same formula, in being 
 •39 for this depth, Q = '39 X 3'83 X '677 ,/64 X '677 = 6'66 cubic feet, and the theoretical power due 
 to the water was 6'66 X 62'6 X 8'41 X 60 = 210,000 lbs. raised 1 foot per minute == 6'36 horse-power. 
 
 It was found that 63 pounds balanced the lever at 49 revolutions per minute of the shaft. Hence 
 the power developed by the wheel was 49 X 63 X 50 = 164-350 lbs. = 4'98 horse-power. 
 
 The coefficients are, then, for experiment No. 1, = '760 per ct. 
 
 “ “ “ No. 2, — =-783 
 
 6'66 
 
 And making allowance for leakage around the waste-board box, which was partially counterbalanced 
 by the friction of the geering and horizontal shaft, the useful coefficient of the wheel may be taken at 
 75 per cent., and, as has been seen, remains the same when the wheel is working at 5 horse-power, 
 which is but 70 per cent, of its full power. 
 
 For the information of those who are not familiar with this wheel, it may be stated that it is placed 
 as near the top of the fall as possible, and revolves within a cast-iron pipe leading below the level of 
 the tail-race. The “ curved guides” are directly over the wheel, and may, therefore, be easily reached 
 for cleaning or repair These curved guides are disposed radially around a hub, curving spirally around 
 it as they descend, in such a manner that any horizontal linear element of a ^uide is in a radial line 
 drawn from the axis. The buckets of the wheel are similarly curved, but in an opposite direction. 
 
 The following experiments were made on one of the 60-horse power turbines of Messrs. Jessup & 
 Moore, with a dynamometer of Prony, and the quantity of water calculated by an overflow discharging 
 in the open air. 
 
 JXCxW 
 
 Effective power = S 3 Q 0 0 — num ^ er rev °l u ti° ns P er minute; C, circumference of the lever; 
 
 W, the weight of the lever and balance. 
 
 R = 104. C = 80 feet. W = 223-50 lbs. 
 
 Effective power 
 Theoretical power of the water = 
 
 104 X 80 X 223-50 
 
 33000 
 
 Q X 62-5 X F 
 
 = 56'30 horse-powei. 
 
 33000 
 
 Q, number of cubic feet of water discharged 
 
 through the wheel per minute. 62'5, weight in pounds of the cubic feet of water. F, fall of the water 
 in feet and fraction. 
 
 The quantity of water was measured by an overflow of 17 2‘87 5 inches width. The depth of water 
 discharging through it was 13j-^- inches. This, with the coefficient of contraction, 0’45, adapted by Mr 
 Poncelet for large overflows, gives 3794 cubic feet of water per minute. The total fall during the op- 
 eration of the turbine was 8 feet lOf inches, = 8-89 feet. 
 
WATER-WHEELS. 
 
 897 
 
 Hence the theoretical power is 
 
 3794 X 62-5 X 8‘89 
 
 33000 
 
 88 coefficient of the turbine. 
 
 63'92 horse-power. 
 
 Effective power, 56'30 ) „ 
 
 Theoretical power, 63 92 j 
 General description of the Jonval Turbine. — Fig. 3823 represents a vertical section of a turbine. A 
 represents the movable wheel , consisting of a cast-iron rim, having a given number of wrouglit-iron buck- 
 ets, of the proper curve, mortised into and riveted to it, and occupying the space marked B ; it is keyed 
 to the main or upright shaft C, and revolves freely in the cylinder D, the outside of the buckets and the 
 cylinder having a small space between them. The stationary wheel E consists of a cast-iron rim, hav 
 
 ing also a given number of wrouglit-iron guides mortised into and riveted to it, and occupying the space 
 F. This wheel occupies the conical part of the cylinder, just above the movable wheel, with sufficient 
 space between them to allow the movable wheel to revolve freely. The upper edges of the guides are 
 level with the upper surface of the flanch of the cylinder. The upright shaft 0 has its lower bearing or 
 step running in the oil-box H; the upper bearing C', runs in a pedestal attached to the bridge G. This 
 bridge, made of cast-iron, is supported on some of the cross timbers of the forebay, and supports also 
 the pedestal for the journal of the line-shaft J. 
 
 3826. 
 
 I 
 
 The oil-box H, is supported by the cast-iron bridge M, which rests on the lugs 1ST N, on the inside of 
 the cylinder. The gate 0, resembling a throttle-valve, is fastened to the shaft P, which works in stuff- 
 ing-boxes, cast in the cylinder. To one end of this shaft a worm-wheel is attached, which, being moved 
 by the endless-screw R, opens and shuts the gate. 
 
 Vol. II— 57 
 
81)8 
 
 WATER-WHEELS. 
 
 The screw R is moved by the hand-wheel or governor S. The cylinder D D D, cast in one or mor« 
 pieces, is supported by the timbers T T. U represents a section of the forebay and tail-race. The oil- 
 box is filled with oil through the gas-tube a, which runs from the top of the forebay. The tube marked 
 b is to allow the air to escape from the box when it is being filled ; that marked c is for drawing off the 
 oil when it is necessary to change it. Should the step wear any, the toe can be changed wifh great 
 facility. The oil-box is held to its proper position in the bridge by set-screws h h. As it is represented 
 in the different figures of this article, there are sometimes wooden steps where it is preferred. 
 
 The operation of the wheel . — The operation of this wheel is very simple ; the top of the cylinder is 
 placed from 4 to 6 feet from the upper level of the water, or at a sufficient distance to prevent the 
 water from becoming agitated ; thus it will be seen that the movable wheel or turbine is suspended 
 between the two levels of the fall. The water is made to come on the wheel and leave it so as to exert 
 
WATER-WHEELS. 
 
 899 
 
 its utmost effect by the proper construction of the guides and buckets, which, together, form an annular 
 section. The following is the action of the water discharging through the wheels. 
 
 The water, as it leaves the forebay, follows the guides of the stationary wheel, curved in a spiral 
 form, and leaves them at an angle of 16° to the horizontal line and tangential to the circumference, and 
 thus presses on the movable wheel, which, by the proper course of its buckets, retrogrades and lets the 
 
 water descend in a spiral direction. Then, by the contracted form of the buckets of the movable whee., 
 the water has a second action, that of lifting the wheel in the direction of 18° to the horizontal line and 
 tangential to the circumference ; this second action is upon the principle of discharge of water through 
 a conical pipe, and has the effect of throwing the pipe back. 
 
 These two forces are in the proportion of 10 to 1, and in constructing the parallelogram of forces in 
 the respective directions, the diagonal or resultant will be at an angle of 11° to the horizontal line and 
 tangential to the circumference. 
 
900 
 
 WATER-WHEELS. 
 
 The water discharged through this contracted space falls in a large air-tight cylinder, and descends, 
 partially suspended by the tendency of vacuum , to the tail-race. The following is the effect of the col 
 umi. of water on the wheel. 
 
 As mentioned above, the column of action on these kind of turbines is divided into two distinct ones- 
 1st, from the upper level of the fall to the upper part of the turbine; 2d, from the upper part of this 
 turbine to the lower level of the fall. 
 
 i 
 
 The first part of the column operates by the same laws as in ordinary wheels, that is to say, the 
 quantity of water multiplied by the velocity corresponding to the height of the fall. The second part 
 of the column, that is to say, from the turbine to the lower part of the fall, would, in ordinary wheels 
 which discharge in open air, be of no additional effect to the wheel, as the water would leave this point 
 without velocity, and would only fall by its gravity ; but by this peculiar arrangement of excluding the 
 air from the whole column by means of an air-tight cylinder immersed in the lower level of the fall, the 
 water passing through a contracted part of the air-tight cylinder discharges in a larger part, which also, 
 below, has a larger discharge than admission from the wheel. 
 
 The water, consequently, cannot fill the wholu space of the cylinder below the wheel, and the ail 
 would rush in to till the vacant space, but this element being completely excluded, the tendency to 
 
WATER-WHEELS. 
 
 901 
 
 form a vacuum keeps the column of water suspended to the proportion of the height to that of perfect 
 vacuum ; and the velocity which the water would, through its gravity, acquire at the lowest part of its 
 fall, would be communicated to the upper part, where, instead of pressure, the water acts as suction. 
 
 This principle is true as far as the tendency of vacuum can be rendered perfect, (that is to say, to the 
 height of 32 feet,) and thus produce by suction an equal in effect to the atmospheric pressure ; above 
 this the surplus of pressure would force air in the column from below, and so reduce the effect, which, 
 in placing the wheel below 32 feet from the lower level, would be equal to pressure. 
 
 Reduction of power in the wheel . — The difference of quantity of water in dry and wet seasons, and 
 also the difference of power used in certain kinds of mills, at different times, in the working operations, 
 have shown that it is necessary for these iron wheels to be adaptable to these changes. 
 
 In consequence of their operating with much higher speed than wooden wheels, the difference of 
 power affects its operation more sensibly if there is no means to regulate it. 
 
 Various forms of gates have been tried, but not found to give full satisfaction. In these wheels there 
 have been employed a series of movable divisions, by which a part of the inner periphery of the wheel 
 is inclosed, and the whole water to be absorbed is thrown to the external periphery. This arrangement 
 has been most satisfactory in its operation, and a wheel used for 60 horse-power in wet seasons can 
 operate at 40 horse-power in dry seasons, and does not vary in its percentage more than 5 to 6 per 
 cent, in its effect by this change. 
 
 It will require only half an hour to insert these divisions, but for instant change of speed or power, 
 there is also the gate by which one-fifth of its power can be taken off without any considerable change 
 in effect. 
 
 Advantages obtained by these wheels over other first-class wheels . — 1st. In consequence of its suspen- 
 sion between the two levels of the fall, in case of backwater, the power only changes by its diminution 
 of fall, but should the fall remain the same, the backwater would not have a bad effect. 
 
 2d. As expressed above, the velocity of turbines in general is greater than that of wooden wheels, 
 and in all factories and mills where a high velocity is required, the amount of power absorbed in the 
 geering is gained, and the use of greasing and chance of getting out of order is greatly lessened. 
 
 3d. As shown in Figs. 3827, 3828, and 3842, the water can ieave the wheel at any angle, even to the 
 horizontal line, and such presents very great advantages where there exist rocks below, or quicksand, 
 or structures which could not be removed without much expense. 
 
 4th. By the position of the stationary wheel placed above the movable, where it is suspended in the 
 conical part of the air-tight cylinder, and its only being kept down by the column of water above and 
 its own weight, it cannot present the chance of breaking should some stick or stone come between its 
 plates, as would be the case in Fourneyron’s wheels, which are bolted to their respective places. A 
 Jonval turbine will, by such obstruction, have the stationary wheel lifted out of its place. In other 
 wheels, where the guides cannot give way, the division plates must be broken. 
 
 5th. In breast, pitchback, and overshot wheels, the water acts partly by its weight and partlv by the 
 velocity due to the head on the gates of discharge, on the wheel, and on this account loses a head of 
 water equal, first, to the half of the head on the gate ; second, the depth of the buckets on the wheel 
 itself. In turbine wheels this is not the case, as the full fall is utilized. 
 
 6th. In case of repair this wheel can be rendered instantly dry and accessible, while all other iron 
 wheels, acting only by pressure, are submerged, and in order to reach the wheel the watci nas to be 
 pumped out of the tail-race. 
 
002 
 
 WEIGHTS AND MEASURES. 
 
 Tlie Jonval turbines are guarantied to give, 1st, *75 per cent, of its effect with a fall fiom 30 feet and 
 above clown to 12 feet. 2d, TO per cent, of its effect with a fall from 12 feet to 6 feet, fed, 60 per 
 cent, of its theoretical effect from 6 feet to 4 feet. 
 
 These wheels are built by Mr. E. Geyelin, Philadelphia. 
 
 Figs. 3827 and 3828, elevation and plan of a 15 horse-power turbine, built by E. Geyelin for Mr. Le 
 Carpentier, Philadelphia. Fig. 3824, section of the turbine-wheel of the same. 
 
 Figs. 3840 and 3841, plan and elevation of a turbine of 50 horse-power, 22 feet fall, in operation in 
 the paper-mill of Messrs. Manning, Peckham, A Howland, of Troy, New York, built at the West Point 
 Foundry, by E. Geyelin. 
 
 Fig. 3842, turbine built at the powder-works of the Messrs. Dupont, Wilmington, Delaware. 
 
 Fig. 3843, turbine built for the Fairmount Water-works of Philadelphia. 
 
 WEIGHTS AND MEASURES. The weights and measures of this country are identical with 
 those of England. In both countries they repose, in fact, upon actually existing masses of metal (brass) 
 which have been individually declared by law to be the units of the system. In scientific theory they 
 are supposed to rest upon a permanent and universal law of nature — the gravitation of distilled 
 water at a certain temperature, and under a certain atmospheric pressure. And in this aspect, the 
 origination is with the giains, which must be such, that 252,458 of these units, in brass, will be in just 
 equilibrium with a cubic inch of distilled water, when the mercury stands at 30 inches in a barometer, 
 and in a thermometer of Fahrenheit at 62 degrees, both for the air and for the water. Unfortunately, 
 the expounders of this theory in England used only the generic term brass, and failed to define the 
 specific gravity of the metal to be employed ; the consequence of this omission is to leave room for an 
 error of jq^ViTo ' n ever )' attempt to reproduce or compare the results. This is the minimum possible 
 error : the maximum would be a fraction of the difference in specific gravity between the heaviest and 
 lightest brass that can be cast. 
 
 Length. — 1 yard = 3 feet = 36 inches = 432 lines = 5184 seconds = 62,208 thirds. 
 
 In the actual government standards at the custom-houses, the yard is divided decimally into tenths 
 and hundredths. 
 
 In the measurement of cloths, muslins, linens, cottons, silk, and in general of what are termed dry 
 mods, the yard only is .used — subdivided into halves, quarters, eighths, sixteenths, and half-sixteenths. 
 This lowest denomination = IT 25 inch. 
 
 Surveyors and engineers employ neither the yard nor the inch, but use the foot and its decimal 
 divisions. 
 
 Architects and artificers reckon by the foot and subdivisions, as given above. Nevertheless, the most 
 usual and most recent workmen’s scales bear the foot divided into inches, and eighths and sixteenths 
 of an inch. 
 
 Mariners measure by cable-lengths and fathoms : 
 
 1 cable-length = 120 fathoms = 240 yards = 720 feet. 
 
 The unit of length — the yard, upon whose subdivisions all the weights and capacity measures repose 
 for verification — is, in fact, derived from ancient arbitrary standards of England. In theory, the inch — 
 the l-36th of the yard — is presumed to be contained 39T3929 times in the length of a pendulum that, 
 in a vacuum, and at the level of mid-tide, under the latitude of London, vibrates seconds of mean time. 
 
 Itinerary . — 1 statute mile = 2 half miles = 4 quarter miles = 7J cable-lengths = 8 furlongs = 80 
 chains = 320 perches or poles = 880 fathoms = 1760 yards = 5280 feet = 8000 links = 63,360 inches. 
 
 1 nautical league = 3 equatorial miles = 3457875 statute miles. 
 
 Chains and links are denominations employed by land surveyors, thus : 
 
 1 chain = 4 poles = 66 feet = 100 links. 
 
 Agrarian and superficial. — 1 square mile = 640 acres. 
 
 1 acre = 4 roods = 10 square chains = 160 square perches = 4840 square yards = 43,560 square feet 
 1 square yard = 9 square feet = 1296 square inches. 
 
 Architects and builders reckon 1 square = 100 square feet. 
 
 Liquid capacity . — 1 gallon = 2 half gallons = 4 quarts = 8 pints = 16 gills. 
 
 The gill is not among existing standards of public authority, though it is used in commerce. There 
 are other denominations higher than the gallon, such as barrels, hogsheads, pipes, etc., but these are 
 only vessels, not measures, and are always gaged and sold by their actual capacity in gallons. The 
 gallon, in fact, is almost exactly equivalent to a cylinder 7 inches in diameter and 6 inches high. In 
 theory, it must contain just 231 cubic inches ; and, filled with distilled water at the temperature of maxi- 
 mum density, (say 39° - 8 Fall.,) weighs, according to the official report, at that temperature, and at 30 
 inches of the barometer, 8339 commercial or avoirdupois pounds; or, more nearly, 58372T754 grains. 
 It is in the temperature only that this unit differs from the former wine-gallon of Great Britain. 
 
 The apothecaries use the same gallon, but divide it differently, as follows : 
 
 1 gallon = 8 pints = 128 fluid ounces = 1024 fluid drachms = 61,440 minims (or drops) = 231 
 cubic inches. 
 
 These are graduated measures : they also use sometimes the following approximate ones from vessels 
 in domestic use : 
 
 1 tea-cup = 2 wine-glasses = 8 table-spoons = 32 tea-spoons = 4 fluid ounces. 
 
 Dry capacity. — 1 bushel = 2 half bushels = 4 pecks = 8 gallons. 
 
 There are also in this, as in the former measure, higher denominations (barrels, sacks, etc.) known in 
 commerce, wdiose capacity is intended to be constant. They are, however, always gaged by the 
 bushel. This bushel is the old Winchester bushel of England. In fact, it is a cylinder 18:5 inches in 
 
WEIGHTS AND MEASURES. 
 
 908 
 
 diameter, and 8 inches deep. In theory, it must contain 2150-42 cubic inches, and holds, of distilled 
 water at the temperature of maximum density, and at 30 inches of the barometer, 77 6274 commercial 
 or avoirdupois pounds; or, more nearly, 543391-89 grains. 
 
 Solid. 
 
 1 cubic yard = 27 cubic feet = 46,656 cubic inches. 
 
 1 cubic foot = 12 reduced feet (plank measure) = 1728 cubic inches. 
 
 1 reduced foot (plank measure) = 1 square foot X 1 inch thick = 144 cubic inches. 
 
 In practice, all planks and scantlings less than an inch in thickness are reckoned at an inch. 
 
 1 perch of masonry = 1 perch (164 feet) long X 1 foot high X 14 foot thick = 25 cubic feet. 
 
 In fact, the dimensions given for the perch do not result in 25 cubic feet, but this last number ha.* 
 been adopted for convenience. 
 
 1 cord of fire-wood = 8 feet long X 4 feet high X 4 feet deep = 128 cubic feet. 
 
 Weight. 
 
 1 mint or troy pound = 12 ounces = 240 pennyweights = 5760 grains. 
 
 1 apothecary pound = 12 ounces = 96 drachms = 288 scruples = 5760 grains. 
 
 1 commercial pound = 16 ounces = 256 drachms = 7000 grains. 
 
 1 long ton = 20 cwt. = 80 quarters = 2240 commercial pounds. 
 
 1 short ton = 20 hundred weight = 2000 commercial pounds. 
 
 In the actual government standards the ounce troy is divided, decimally, down to the part. 
 
 TABLES OF UNITED STATES WEIGHTS AND MEASURES. 
 
 MEASURES OF LENGTH. 
 
 12 
 
 inches 
 
 
 Inches. 
 
 Feet. 
 
 Yards. Rods. Furl. 
 
 3 
 
 feet 
 
 — 1 yard. 
 
 36 = 
 
 3. 
 
 
 H 
 
 yards 
 
 
 198 = 
 
 164 
 
 = 54. 
 
 40 
 
 rods 
 
 
 7920 = 
 
 660 
 
 = 220 = 40. 
 
 8 
 
 furlongs . . 
 
 
 63360 = 
 
 5280 
 
 = 1760 =320 = 8. 
 
 
 Gunter's Chain. 
 
 
 Bop 
 
 es and Cables. 
 
 7-92 
 
 inches 
 
 . — 1 link. 
 
 6 feet.. 
 
 
 — 1 fathom. 
 
 100 
 
 links 
 
 . — 4 rods, or 22 yards. 
 
 120 fathoms . ... 
 
 
 Geographical and Nautical Measure. 
 
 1 degree of a great circle of the earth ■. = 69-77 statute miles. 
 
 1 mile = 2046-58 yards. 
 
 Log Lines. 
 
 1 knot.'..... = 51-1625 feet, or 5' feet If + inches. 
 
 1 fathom = 5-11625 feet, or 6 feet 1J -f- inches. 
 
 Estimating a mile at 61394 feet, and using a 30" glass. If a 28' glass is used, and eight divisions, then 
 
 1 knot =47 feet 9 -j- inches. 
 
 1 fathom....... = 5 feet Ilf inches. 
 
 The line should be about 150 fathoms long, having 10 fathoms between the chip and first knot for 
 stray line. 
 
 Note. — B owditch gives 6120 feet in a sea mile, which, if taken as the length, will make the divisions 
 51 feet and 5 1-10 feet. 
 
 Cloth. 
 
 1 nail = 2f inches = l-16th of a yard. 
 
 1 quarter :....=4 nails. 
 
 6 quarters =1 ell English. 
 
 Pendulums. 
 
 6 points = 1 line. 
 
 12 lines = 1 inch. 
 
 Shoemakers'. 
 
 No. 1 is 4 J inches in length, and every succeeding number is § of an inch. 
 
 There are 28 divisions, in two series of numbers, viz., from 1 to 13, and 1 to 15. 
 
 Circles. 
 
 60 seconds = 1 minute. 
 
 60 minutes = 1 degree. 
 
 360 degrees = 1 circle. 
 
 1 day is 
 
 1 minute is 
 
 n 
 
 3600 = 60. 
 1296000 = 21600. 
 •002739 of a year. 
 •000694 of a day. 
 
 Miscellaneous. 
 
 1 palm = 3 inches. I 1 span = 9 inches. 
 
 1 hand =4 inches. | 1 metre. = 3-28174 feet. 
 
 The standard of measure is a brass rod, which, at the temperature of ? 2° Fahrenheit, is tho 
 standard yard. 
 
904 
 
 WEIGHTS AND MEASURES. 
 
 1 yard is . ‘000568 of a mile. 
 
 1 inch is ‘0000158 of a mile. 
 
 MEASURES OF SURFACE. 
 
 144 square inches = 1 square foot. 
 
 9 square feet — 1 square yard. 
 
 Land. 
 
 Inches. 
 
 1296. 
 
 Yards. Rods. Roods. 
 
 1210. 
 
 4840 = 160. 
 
 8097600 = 102400 = 2560. 
 
 30} square yards = 1 square rod. 
 
 40 square rods = 1 square rood. 
 
 4 square roods ) , 
 
 ^ ,. V = 1 acre. 
 
 1 0 square chains ) 
 
 640 acres = 1 square mile. 
 
 Note. — 208'710321 feet, 69‘5701 yards, or 220 by 198 feet square = 1 acre. 
 
 Paper. 
 
 24 sheets = 1 quire. I Sheets. 
 
 20 quires = 1 ream. | 480. 
 
 Drawing Paper. 
 
 Cap 
 
 
 Columbier 
 
 .. 33} X 
 
 23 inches 
 
 Demy 
 
 19}X15} “ 
 
 Atlas 
 
 . 33 X 
 
 26 “ 
 
 Medium 
 
 22 X 18 “ 
 
 Theorem 
 
 . 34 X 
 
 28 “ 
 
 Royal 
 
 24 X 19 “ 
 
 Double Elephant.. 
 
 .40 X 
 
 26 “ 
 
 Super-royal 
 
 27 X 19 “ 
 
 Antiquarian 
 
 . 52 X 
 
 31 “ 
 
 Imperial 
 
 29 X 211 “ 
 
 Emperor 
 
 ..40 X 
 
 60 “ 
 
 Elephant 
 
 27} X 22} “ 
 
 Uncle Sam 
 
 ..48 X 
 
 120 ‘ 
 
 MEASURES OF CAPACITY. 
 
 Liquid. 
 
 ■ 1 pint. 
 
 Gills. Pints. 
 
 32 = 
 
 Pints. Qrts. Galls. 
 
 16 = 8. 
 
 64 = 32 = I 
 
 4 gills 
 
 2 pints = 1 quart. 
 
 4 quarts = 1 gallon. 
 
 Dry. 
 
 2 pints = 1 quart. 
 
 4 quarts = 1 gallon. 
 
 2 gallons = 1 peck. 
 
 4 pecks = 1 bushel. 
 
 United States standard bushel. — The standard bushel is the Winchester, which contains 2150’43 
 cubic inches, or 77'627413 lbs. avoirdupois of distilled water at its maximum density. 
 
 Its dimensions are 184 inches diameter inside, 19} inches outside, and 8 inches deep; and whet 
 heaped, the cone must not be less than 6 inches high, equal 2747‘70 cubic inches for a true cone. 
 
 1728 cubic inches = 1 foot. I Inches. 
 
 27 cubic feet = 1 yard. | 46656 
 
 Miscellaneous. 
 
 1 chaldron = 36 bushels, or 57'25 cubic feet. 
 
 1 cord of wood 128 cubic feet. 
 
 1 perch of stone 24‘7 5 cubic feet. 
 
 MEASURES OF WEIGHT. 
 
 Avoirdupois. 
 
 16 drachms = 1 ounce. 1 Drachms. Ounces. Pounds. 
 
 16 ounces = 1 pound. | 256. 
 
 112 pounds = 1 cwt. 28672 = 1792. 
 
 20 cwt = 1 ton. 573440 = 35840 = 2240 
 
 1 lb. 
 
 = 14 oz. 11 dwt. 16 gr. troy. 
 
 Dwt. 
 
 Troy. 
 
 24 grains = 1 dwt. 
 
 20 dwt = 1 ounce. 
 
 12 ounces = 1 pound. 
 
 Apothecaries'. 
 
 20 grains = 1 scruple. 
 
 3 scruples = 1 drachm. 
 
 8 drachms =1 ounce. 
 
 12 ounces = 1 pound. 
 
 Diamond. 
 
 16 parts = 1 grain = 0’8 troy grains. 
 
 4 grains = 1 carat = 3 2 “ 
 
 Grains. 
 
 480. 
 
 5760 = 240. 
 
 Grains. Scruples. Drachms. 
 60. 
 
 480 = 24. 
 
 5760 = 288 = 96. 
 
WEIGHTS AND MEASURES. 
 
 905 
 
 WOO troy grains = 1 lb. avoirdi pois. 
 
 175 troy pounds = 144 lbs. “ 
 
 175 troy ounces = 192 oz. 
 
 437 i troy grains = 1 oz. 
 
 1 troy pound = '8228 + lb- “ 
 
 Miscellaneous. 
 
 1 cubic foot of anthracite coal from . 
 1 cubic foot of bituminous coal from 
 
 1 cubic foot Cumberland coal = 53 lbs. 
 
 1 cubic foot charcoal = 18-5 “ 
 
 1 cubic foot charcoal = 18 “ 
 
 1 cord Virginia pine =2700 “ 
 
 1 cord Southern pine = 3300 “ 
 
 1 stone — 14 “ 
 
 50 to 55 lbs. 
 45 to 55 lbs, 
 
 (hard wood), 
 (pine wood). 
 
 Coals are usually purchased at the conventional rate of 28 bushels (5 pks.) to a ton = 43’56 cubic feet 
 
 MEASURES OF VALUE. 
 
 1 eagle = 258 troy grains. 
 
 1 dollar =412-5 
 
 1 cent = 168 “ 
 
 The standard of gold and silver is 900 parts of pure metal, and 100 of alloy, in 1000 parts of coin. 
 
 MEASURES OF LENGTH. 
 
 British. — Yard is referred to a natural standard, which is the length of a pendulum vibrating sec- 
 onds in vacuo in London, at the level of the sea ; measured on a brass rod, at the 
 temperature of 62° Fahrenheit, = 39-1393 inches. 
 
 French. Old system . — 1 Line — 12 points. 
 
 Inch . 
 
 Foot 
 
 Toise . .. 
 League 
 
 = 12 lines. 
 
 = 12 inches.... 
 
 = G feet 
 
 = 2280 toises 
 = 2000 toises 
 = 5 feet. 
 
 1 League 
 1 Fathom 
 
 “ New system. — 1 Millimetre 
 
 1 Centimetre 
 
 1 Decimetre 
 
 1 Metre 
 
 1 Decametre 
 
 1 Hecatometre 
 
 Austrian 1 Foot 
 
 Prussian 1 Foot 
 
 Swedish 1 Foot 
 
 SrANisH 1 Foot 
 
 1 League (common) 
 
 0'08884 United States inches 
 1-06604 
 
 12-7925 “ “ 
 
 76-755 
 (common). 
 
 (post). 
 
 •03938 
 •39380 
 
 3-93809 “ 
 
 39-38091 “ 
 
 393-80917 “ 
 
 3938-09171 
 12-448 
 12-361 
 11-690 
 11-034 
 
 3-448 United States miles. 
 
 Table showing the relative length of Foreign Measures compared with those of the United States. 
 
 Places. 
 
 Measures. 
 
 Inches. 
 
 Places. 
 
 Measures. 
 
 Inches. 
 
 Amsterdam ... 
 
 Foot 
 
 11-14 
 
 11-24 
 
 11- 42 
 
 12- 19 
 11-38 
 
 11- 45 
 
 13- 12 
 
 12- 71 
 
 13- 32 
 12-58 
 12-35 
 
 11- 14 
 1200 
 21-60 
 
 12- 79 
 39-381 
 19-20 
 
 9-72 
 
 11-29 
 
 11- 45 
 11-11 
 
 12- 96 
 8 p 64 
 
 Malta 
 
 Foot 
 
 11- 17 
 13-17 
 10-38 
 
 12- 36 
 38-27 
 
 12- 35 
 
 10- 79 
 
 11- 60 
 
 13- 75 
 9-78 
 9-53 
 
 11-03 
 
 66-72 
 
 8-34 
 
 11-39 
 
 11- 69 
 
 12- 72 
 
 13- 40 
 12-45 
 11-81 
 10-74 
 14.03 
 
 
 it 
 
 
 Palmo 
 
 Berlin 
 
 ll 
 
 
 Foot 
 
 Bremen 
 
 it 
 
 
 Arish 
 
 
 it 
 
 
 Foot 
 
 
 “ Mathematician’s 
 “ Builders 
 
 
 
 
 Rome 
 
 « 
 
 « 
 
 “ Tradesman’s... 
 “ Surveyor’s 
 
 a 
 
 
 u 
 
 a 
 
 
 Palmo 
 
 Copenhagen ... 
 
 Sicily 
 
 
 ti 
 
 
 Foot 
 
 
 it 
 
 
 
 
 
 a 
 
 
 
 
 Strasburgh 
 
 Sweden 
 
 Foot 
 
 
 
 
 
 
 Turin 
 
 « 
 
 
 
 Venice 
 
 a 
 
 Hamburgh 
 
 
 
 u 
 
 
 
 u 
 
 
 u 
 
 
 tt 
 
 
 a 
 
 
 tt 
 
 
 
 
 
 
 
DOG 
 
 WEIGHTS AND MEASURES. 
 
 Table showing the relative length of Foreign Road Measures compared with those of the United 
 
 States. 
 
 Places. 
 
 Measures. 
 
 Yards. 
 
 Places. 
 
 Measures. 
 
 Yards. 
 
 Arabia 
 
 Mile 
 
 2148 
 
 Hungary 
 
 Mile 
 
 9113 
 
 Bohemia 
 
 ‘t 
 
 10137 
 
 
 
 3038 
 
 China 
 
 Li 
 
 629 
 
 
 « 
 
 1093 
 
 Denmark 
 
 Mile 
 
 8244 
 
 Persia 
 
 Parasang 
 
 6086 
 
 England 
 
 “ Statute 
 
 1760 
 
 Poland 
 
 Mile, long 
 
 8101 
 
 “ 
 
 “ Geographical. 
 
 2025 
 
 Portugal 
 
 League 
 
 6760 
 
 Flanders 
 
 U 
 
 6869 
 
 
 Mile 
 
 8468 
 
 
 
 6075 
 
 
 
 2025 
 
 
 
 4861 
 
 
 
 1167 
 
 u 
 
 
 4264 
 
 
 
 1984 
 
 
 
 10126 
 
 
 
 7416 
 
 
 
 8244 
 
 
 Mile ...' 
 
 11700 
 
 
 il 
 
 11559 
 
 
 
 9153 
 
 Holland 
 
 ll 
 
 6395 
 
 
 
 1826 
 
 
 
 
 
 
 
 — 
 
 Measures of Surface. 
 
 French. 
 
 Old system . — 1 Square Inch 
 
 1 Arpent (Paris) 
 
 1 Arpent (woodland) 
 
 New system . — 1 Are 
 
 1 Decare 
 
 1 Hecatare 
 
 1 Square Metre 
 
 1 Are 
 
 = 1‘1 364 United States inches. 
 
 = 900 square toises. 
 
 =•100 square royal perches. 
 
 = 100 square metres. 
 
 = 10 ares. 
 
 = 100 ares. 
 
 = 1550-85 square inches, or 10-7698 sq. ft 
 = 1076-98 square feet. 
 
 Table showing the relation of Foreign Measures of Surface compared with those of the United States 
 
 Places. 
 
 Measures. 
 
 Sq. yards. 
 
 Places. 
 
 Measures. 
 
 Sq. yards. 
 
 Amsterdam ... 
 
 Morgen 
 
 9722 
 
 Portugal 
 
 Geira 
 
 6970 
 
 Berlin 
 
 “ great 
 
 6786 
 
 Prussia 
 
 Morgen 
 
 3053 
 
 U 
 
 
 3054 
 
 
 
 3158 
 
 Canary Isles... 
 
 
 9490 
 
 
 
 13066-6 
 
 
 4840 
 
 
 Acre 
 
 6150 
 
 
 
 6179 
 
 
 Fanegada 
 
 5500 
 
 Hamburgh 
 
 Morgen 
 
 11545 
 
 Sweden 
 
 Tunneland 
 
 5900 
 
 
 
 3100 
 
 
 Faux 
 
 
 Ireland 
 
 Acre 
 
 7840 
 
 Vienna 
 
 Joch 
 
 6889 
 
 
 
 3998 
 
 
 Common acre 
 
 3875-6 
 
 
 
 
 
 Measures of Capacity. 
 
 British. The Imperial gallon measures 277-274 cubic inches, containing 10 lbs. avoirdupois of 
 distilled water, weighed in air, at the temperature of 62°, the barometer at 30 inches 
 For Grain. 8 bushels = 1 quarter. 
 
 1 quarter = 10’2694 cubic feet. 
 
 Coal, or heaped measure. 3 bushels = 1 sack. 
 
 12 sacks = 1 chaldron. 
 
 Imperial bushel = 2218-192 cubic inches. 
 
 * Heaped bushel, 19-^ inches diameter, cone 6 inches high = 2815 4872 cubic inches. 
 
 1 chaldron = 58'658 cubic feet, and weighs 3136 pounds. 
 
 1 chaldron (Newcastle) = 5936 pounds. 
 
 French. New system . — 1 Litre = 1 cubic decimetre, or 6P074 U. S. cubic inches. 
 
 Old system. — 1 Boisseau = 13 litres = 793'964 cubic inches, or 3'43 gallons. 
 
 1 Pinte = 0-931 litres, or 5 6 ’8 17 cubic inches. 
 
 Spanish. 1 Wine Arroba = 4-2455 gallons. 
 
 1 Fanega (common measure) = 1'593 bushels. 
 
 * When heaped in the form of a true cone. 
 
WEIGHTS AND MEASURES. 
 
 907 
 
 Table showing the relative Capacity of Foreign Liquid Measures compared with those of the 
 
 United States. 
 
 Places. 
 
 Measures. 
 
 Cub. inch. 
 
 Places. 
 
 Measures. 
 
 Cub. inch. 
 
 Amsterdam ... 
 
 Anker. 
 
 2331 
 
 Naples 
 
 Wine Barille 
 
 2544 
 
 « 
 
 
 146 
 
 
 1133 
 
 
 
 194 
 
 Oporto 
 
 
 1555 
 
 Bordeaux 
 
 Barrique 
 
 14033 
 
 Rome 
 
 Wine Barille 
 
 2560 
 
 Bremen 
 
 
 194-5 
 
 
 Oil “ 
 
 2240 
 
 
 
 949 
 
 a 
 
 
 80 
 
 Constantinople 
 
 Almud 
 
 319 
 
 Russia 
 
 Weddras 
 
 752 
 
 Copenhagen ... 
 Florence 
 
 
 2355 
 
 
 
 94 
 
 Oil Barille 
 
 1946 
 
 Scotland 
 
 Pint 
 
 103-5 
 
 U 
 
 
 2427 
 
 Sicily 
 
 
 662 
 
 
 
 61-07 
 
 
 
 22'5 
 
 
 Setier 
 
 2760 
 
 
 
 30-5 
 
 Genoa 
 
 Wine Barille 
 
 4530 
 
 Sweden 
 
 Eimer 
 
 4794 
 
 
 Pinte 
 
 90-5 
 
 Trieste 
 
 
 4007 
 
 Hamburgh 
 
 Stubgen 
 
 221 
 
 Tripoli 
 
 Mattari 
 
 1376 
 
 
 
 231 
 
 
 Oil “ 
 
 1157 
 
 628 
 
 Hungary 
 
 Eimer 
 
 4474 
 
 Venice 
 
 Seccliio 
 
 Leghorn 
 
 Oil Barille 
 
 1942 
 
 Vienna 
 
 Eimer 
 
 3452 
 
 Lisbon 
 
 Almude 
 
 1040 
 
 « 
 
 
 86-33 
 
 Malta 
 
 Caffiri 
 
 1270 
 
 
 
 Table showing the relative Capacity of Foreign Dry Measures compared with those of the United 
 
 States. 
 
 Places. 
 
 Measures. 
 
 Cub. inch. 
 
 Places. 
 
 Measures. 
 
 Cub. inch. 
 
 Alexandria 
 
 Rebele 
 
 9587 
 
 Malta 
 
 Salme 
 
 16930 
 
 “ 
 
 Kislos 
 
 10418 
 
 Marseilles 
 
 Charge 
 
 9411 
 
 Algiers 
 
 Tarrie 
 
 1219 
 
 Milan 
 
 Moggi 
 
 8444 
 
 Amsterdam ... 
 
 Mudde 
 
 6596 
 
 Naples 
 
 Tomoli 
 
 3122 
 
 
 Sack 
 
 4947 
 
 Oporto. .' 
 
 Alquiere 
 
 1051 
 
 Antwerp 
 
 Viertel 
 
 4705 
 
 Persia 
 
 Artaba 
 
 4013 
 
 Azores 
 
 Alquiere 
 
 731 
 
 Poland 
 
 Zorzec 
 
 3120 
 
 Berlin 
 
 Scbeffel 
 
 3180 
 
 Riga 
 
 Loop 
 
 3978 
 
 Bremen 
 
 
 4339 
 
 
 
 16904 
 
 Candia 
 
 Charge 
 
 9288 
 
 
 
 49.0fi 
 
 Constantinople 
 
 Kislos 
 
 2023 
 
 Rotterdam .... 
 
 Sach 
 
 6361 
 
 Copenhagen ... 
 
 Toende 
 
 8489 
 
 Russia 
 
 Chetwert 
 
 12448 
 
 Corsica 
 
 Stajo 
 
 6014 
 
 Sardinia 
 
 Starelli 
 
 2988 
 
 Florence 
 
 Stari 
 
 1449 
 
 Scotland " 
 
 Firlot 
 
 2197 
 
 Geneva 
 
 Coupes 
 
 4739 
 
 
 
 91 014 
 
 Genoa 
 
 Mina 
 
 7382 
 
 
 
 1 
 
 Greece 
 
 Medimni 
 
 2390 
 
 Smyrna 
 
 Kislos 
 
 2141 
 
 Hamburgh 
 
 Scheffel., 
 
 6426 
 
 Spain 
 
 Catrize 
 
 41269 
 
 Hanover 
 
 Malter 
 
 6868 
 
 Sweden 
 
 Tunnar .1 
 
 8940 
 
 Leghorn 
 
 Stajo 
 
 1501 
 
 Trieste 
 
 Stari 
 
 4521 
 
 “ 
 
 Sacco 
 
 4503 
 
 
 
 19780 
 
 Lisbon 
 
 Alquiere 
 
 817 
 
 
 
 21 855 
 
 
 Fanega 
 
 3268 
 
 
 
 4945 
 
 Madeira 
 
 Alquiere 
 
 684 
 
 Vienna 
 
 Metzen 
 
 3753 
 
 Malaga 
 
 Fanega 
 
 3783 
 
 
 
 
 French. 
 
 Measures of Solidity. 
 
 1 Cubic foot 
 
 Decistre 
 
 Stere (a cubic metre) 
 
 Decastere 
 
 1 Stere 
 
 = 2093-470 U. S. inches. 
 = 3-5375 cubic feet. 
 
 = 35'375 “ 
 
 = 353-75 
 
 = 6107T1564 
 
 Measures of Weight. 
 
 British 1 troy Grain == .003961 cubic inches of distilled water. 
 
 1 troy Pound = 22-815689 cubic inches of water. 
 
 French. Old system. — 1 Grain = 0-8188 grains troy 
 
 1 Gros = 58-9548 “ 
 
 1 Once = 1 0780 oz. avoirdupois. 
 
 1 Livre = 1-0780 lbs. “ 
 
908 
 
 WHEELS. 
 
 Measures of Weight- 
 
 French. New system. — Milligramme 
 
 Centigramme 
 
 -Continued. 
 
 = "01543 troy grains. 
 
 — "15433 
 
 = 1-54331 
 
 = 15-43315 
 
 = 154-33159 
 
 = 1543-3159 
 
 Decigramme 
 
 Gramme 
 
 Decagramme 
 
 Hecatogramme 
 
 1 Millier = 1000 Kilogrammes = 1 ton sea weight. 
 
 Spanish ... 
 Swedish . 
 Austrian . 
 
 1 Kilogramme 
 
 1 Pound avoirdupois 
 
 1 Pound troy 
 
 . 1 “ 
 
 . 1 “ 
 
 . 1 “ 
 
 Prussian 1 
 
 2’20 4737 lbs. avoirdupois. 
 0-4535685 kilogramme. 
 
 0- 3732223 
 
 1- 0152 lbs. avoirdupois. 
 
 0- 9376 
 
 1- 2351 
 1-0333 
 
 Note. — In the new French system, the values of the base of each measure, viz., Metre, Litre, St era, 
 Are, and Gramme, are decreased or increased by the following words prefixed to them. Thus, 
 
 Milli expresses the 1 000th part. 
 
 Centi “ “ 100 th “ 
 
 Deci “ “ 10 th “ 
 
 Deca “ “ 10 times the value. 
 
 Hecato expresses 100 times the value. 
 
 Chilio “ 1000 
 
 Myrio “ 10000 “ 
 
 Table showing the relative value of Foreign Weights compared with those of the United States. 
 
 Places. 
 
 , Weights. 
 
 Number 
 equal to 
 100 avoir- 
 dupois 
 pounds. 
 
 Places. 
 
 Weights. 
 
 Number 
 equal to 
 100 avoir- 
 dupois 
 pounds. 
 
 
 Rot toll 
 
 2046 
 
 
 
 93-20 
 
 
 Oke 
 
 35*80 
 
 
 Catty 
 
 76-92 
 
 
 Rottoli 
 
 107- 
 
 
 Pound 
 
 133-56 
 
 
 
 84- 
 
 
 “ (common)... 
 “ (silk) 
 
 97-14 
 
 Amsterdam ... 
 
 Pound 
 
 9P8 
 
 Lyons 
 
 98-81 
 
 
 
 
 
 143-20 
 
 
 
 112*6 
 
 
 Maund 
 
 33-33 
 
 Batavia 
 
 Catty 
 
 70-78 
 
 Morea 
 
 Pound 
 
 90-79 
 
 Bengal 
 
 Berlin 
 
 Seer 
 
 53-57 
 
 Naples 
 
 Rottoli 
 
 5091 
 
 Pound 
 
 96-8 
 
 Rome 
 
 Pound 
 
 133-69 
 
 
 
 125*3 
 
 
 
 91-80 
 
 
 « 
 
 90*93 
 
 
 « 
 
 110-86 
 
 
 « 
 
 97*14 
 
 Sicily 
 
 (4 
 
 142-85 
 
 
 
 105* 
 
 
 Oke 
 
 
 
 
 85-9 
 
 
 Catty 
 
 
 
 
 
 
 Pound 
 
 106-67 
 
 Constantinople 
 Copenhagen ... 
 
 Oke. 
 
 3555 
 
 
 
 120-68 
 
 Pound 
 
 90-80 
 
 Tangiers 
 
 “ (miner’s) 
 
 94-27 
 
 
 
 131-72 
 
 
 Rottoli 
 
 89-28 
 
 
 
 19-07 
 
 
 
 9009 
 
 
 
 25-28 
 
 
 Pound (heavy) 
 
 94-74 
 
 
 
 133.56 
 
 
 “ (light)! 
 
 150- 
 
 
 
 82*35 
 
 
 
 81- 
 
 
 
 92-86 
 
 
 « 
 
 112-25 
 
 Hamburgh 
 
 “ “ 
 
 93.63 
 
 
 
 To convert English Imperial gallons into United States gallons, multiply by 1-20032. And to con- 
 cert United States gallons into English Imperial gallons, multiply by -83311. 
 
 For an extended view of the various systems of weights and measures in use, see a work on this 
 subject by Professor J. H. Alexander, of Baltimore. 
 
 WHEELS. Under this head we give a few of the best forms of railroad-car wheels in use. Se« 
 also A ppendix. 
 
 3844— g. Hawks’ patent, 1807. 3845, 3846— W. Losh & G. Stephenson’s patent, 1816. 
 
 
WHEELS. 
 
 DO [ J 
 
 3858 — B. Hicks’ patent, 1834. 
 
 3859 — R. Whiteside’s patent, 1834. 
 
 3860— W. B. Adams’ patent, 1835. 
 
 38G1 — I. Day’s patent, 1835. 
 
 3862— R. R. Reinagle’s patent, 1836. 
 
 3863 — H. Van Wart’s patent, 1830. 
 
 38CG — G. Cottam’s patent, 1837 
 
 3869 — J. Grimes’ patent, 1838. 
 
910 
 
 WHEELS. 
 
 3870. ...I F. Rnurne & I. Bartley’s patent, .838. . .3871. 
 
 3872—1. Rivington, 1839. 
 
 3885 1. O. Young 3886 Patented in 1811 3887. 
 
WHEELS. 
 
 911 
 
 3891 VV. Losh 
 
 3892 Patented in 1842 3893. 
 
 3894— T. Banks’ patent, 1842 
 
 3903 Thomas Melling 3904 
 
 Patented in 184G 3905. 
 
 3908 — H. Grafton’s patent, 1847, 
 
 3909 — B. P. Stratton’s 
 
 patent, 1847 
 
 3910— F. Abate, registered in (847. 3911-F. Chaplin’s patent, 1847. 
 
912 
 
 WHEELS, PADDLE. 
 
 3912 — VV. E. Newton’s patent, 1847. 
 
 3913 — G. Stephenson & Co. 
 
 3914— Locomotive-engine wheel. 
 
 3915 — I. G. Bodmer, 1842. 
 
 3918 — Bristol and Exeter Railway, 1840. 
 
 WHEELS, PADDLE, the wheels employed in the propulsion of steamboats. Common paddle- 
 wheels mostly consist of iron framing, supporting paddle-boards or floats fixed at equal distances around 
 the rim, and radiating from the centre ; they are placed one upon each side of the vessel, and are se- 
 cured to a strong shaft passing across it, which is turned round by the engines, each engine working a 
 crank fixed upon it ; and are placed at right angles to each other. Fig. 3920 represents the common 
 paddle-wheel. 
 
 3920. 
 
 3923. 
 
 There is a supposed loss of power attending this description of wheel, on account of only one of the 
 floats striking the water in a vertical position at the same time, the action of the others being oblique; 
 some of them, in fact, backwater, or partially oppose the motion of the vessel. Attempts have been made 
 to obviate these defects by constructing improved wheels, the paddles of which maintain a vertical po- 
 sition in their passage through the water, when in front of the wheel, by having feathering floats, and 
 these are called vertical paddle-wheels. Figs. 3921 and 3922 represent a section and elevation of the 
 vertical paddle-wheels of the “ Medea.” They have been found to answer well for sea-going packets, 
 where the paddle-wheels are deeply immersed in the water; but they are more liable to derangement 
 than the ordinary wheels ; the floats may be made to leave the water at any required angle. Mr. P. 
 W. Barlow, C. E., states the proportion of the power expended on Morgan's vertical wheels at 546, and 
 of the former at 151 to 197. 
 
 The Cycloidal paddle-wheel, Fig. 3923, (the paddle-wheel of the “Great 1768161-0,”) forms, the most 
 recent improvement, and is said to possess the advantages of each of the former, being effective and 
 strong, yet simple, in point of construction. It was patented by Mr. Galloway in the year 1835, although 
 first used by Mr. Field in 1833. The floats are divided into a number of parts, which are placed upon 
 
WIRE ROPE MACHINERY. 
 
 913 
 
 the wheel in the curve of a cycloid, so that they enter the water at the same, spot, and follow one an- 
 other so rapidly as to cause little resistance to the engine ; in passing the centre, there is full scope to 
 their action, and in coming out they allow the water to escape readily from them. 
 
 The draught of the vessel is necessarily greatest at the commencement of a voyage, particularly if 
 it should be a long one, on account of the full quantity of coals for the whole voyage increasing the 
 amount of tonnage, and other similar contingencies ; the wheels are, therefore, immersed very deep in 
 the water, which has the etfect of increasing the resistance ; but this loss of power diminishes as the. 
 
 3921. 
 
 3922. 
 
 vessel proceeds. The adjusting of the floats of paddle-wheels to the requisite depth of immersion is 
 called reefing the fi oats, and there is some difficulty connected with it ; but this defect may be partly 
 rectified with the cycloidal wheels, as the outer floats need not be fixed at starting, but fitted on as the 
 voyage proceeds ; and the larger the wheel, the less will the vessel be affected by this defect, as the 
 diameter of the wheel increases in a greater proportion than the variation of immersion of the vessel ; 
 the latter is consequently proportionately less than other vessels, when each are laden. 
 
 WIRE COVERING- MACHINE. Fig. 3924 is a simple, machine for covering bonnet or telegraph 
 wire, and which may be easily constructed. There are other kinds of machines which we have seen in 
 operation that can cover five and six wires at 
 once, but this one is certainly not surpassed for 3924. 
 
 simplicity. 
 
 A A, sole of machine, made of wood, into 
 which are mortised the two uprights B B, only 
 one of which is shown — they are placed about 
 three inches apart; C, upright frame for carry- 
 ing shaft D and tube E ; F F, two rollers for 
 drawing through the wire as it is covered : the 
 top roller is made of lead, so as to give pres- 
 sure to the wire to take it through ; E, tube or 
 hollow spindle through which the wire passes ; 
 
 G G, spur-wheel and pinion for driving hollow 
 spindle and bobbin A ; I, brackets for carrying 
 end of hollow spindle ; J, endless-screw for 
 working the pulley-wheel 0, fixed on the outer 
 end of the under-roller F ; K, support for 
 steadying the wire as it passes through the 
 
 spindle E. H, bobbin containing the thread for covering the wire ; L is a small eye fixed into the fram6 
 that carries the bobbin, through which the thread passes on to the wire. In using the machine the 
 wire to be covered is held by the hands, and kept stretched as it is drawn through by the two roll- 
 ers ; another pair of rollers might be applied to keep the wire stretched, the same as the drawing-rollers. 
 
 WIRE ROPE MACHINERY. The machinery by which so intractable a material as iron wire, 
 when compared with hemp, is spun into a rope, is most simple and complete, and has been patented 
 in England by Mr. Smith. As the drums on which the wire is wound deliver it to the spinning portion 
 of the machinery, the rope, beautifully and regularly finished, is seen flying away with inconceivable 
 rapidity, and the harmony, smoothness, and freedom from jar or strain with which the whole works is 
 truly admirable. The motion is entirely new for such a purpose, being without wheels, and is effected 
 by a mechanical arrangement similar to an orrery, or the sun and planet motion ; it effects great econo- 
 my in working cost from the decreased friction, takes up much less space than the ordinary machines, 
 and makes but little noise when in most rapid operation. The following is the specification and de- 
 scription : 
 
 Firstly, my invention, in so far as it regards machinery for, or methods of manufacturing rope or cord- 
 age, has relation to the means employed to give motion to the reels or bobbins in laying the yarn or 
 wire into strands, or in laying strands into rope or cordage, and consists in the improved arrangements 
 Vol. II. — 58 
 
on 
 
 WIRE ROPE MACHINERY. 
 
 for that purpose represented in Figs. 3925 and 3926, the former of which is a plan of the machinery or 
 the line y x, and the latter a side elevation thereof. The bobbins or reels gg (of any convenient num- 
 ber) are mounted in a circular frame A, which is upheld by screw-rods v v, with an outer framework A 1 
 consisting of a basement k, four pillars pp, an entablature y 1 , spandrills x‘ x 1 , and conical apex w. The 
 principal parts of the frame A are three six-armed rings R 1 , R 2 , R 3 , which are connected vertically to 
 
 gether in the manner to be presently explained, and two laying-plates 1 1 at top of all. The undermost 
 ring R 1 , is connected by a series of cranks Gee, with the second ring R 2 , and R 2 with the third ring F„ 3 , 
 by straight vertical rods s s. The centre crank C is stationary, and stepped by its short arm in a pe- 
 destal N, attached to the basement of the outer framework A 2 , while the undermost ring R 1 is attached 
 to a loose boss r, slipped over the short arm of the crank C, so that on a rotating movement being given 
 
 to the ring R 1 , it carries round with it the ring R 2 by means of the side-cranks e e — that is to any, the 
 side-cranks e e, which may be called live cranks, are made to revolve round the centre or dead crank 
 C ; while the ring R 2 in its turn imparts, through the medium of the vertical rods ss, a simultaneous ro- 
 tary movement to the top ring R 3 . The long arms of the connecting cranks e e carry the reels or bob- 
 bins gg, on which the yarn or wire is wound, and as they revolve at fixed and invariable distances 
 
WOODS, VARIETIES OF. 
 
 •DM 
 
 ror.nd the centre or dead crank C, any twist of the yarn or wire, which is in the course of being laid, is 
 effectually prevented. The requisite rotary motion is given to the machine by means of a pair of bevel- 
 wheels B 1 and B 2 , the former of which (B 1 ) is attached to the loose boss r on the short arm of the dead 
 crank C, and the latter (B 2 ) to a shaft S, which is turned by a steam-engine, or other first mover, through 
 the medium of the riggers a a. The long arm of the dead crank 0 carries at top a reel or bobbin u, 
 from which the heart or core for the rope or cordage (of whatever material such heart or core may be) 
 is supplied. The yarns or wires from the different bobbins pass through guide-holes in the topmost ring 
 R 3 , and meet and unite with the core at the laying-plates tt. To the revolving shaft S, and at a little 
 distance from the riggers a a, there is attached a worm-wheel h, the threads of which take into a tan- 
 gent-wheel i, and thereby give motion to a whelp-wheel/ keyed to the axis k 1 , of i. The whelp-wheel 
 »' serves to receive or take away the strand or rope as it is delivered from the twisting or bobbin-frame 
 A over the pulley Q. The whelps 1 1 of the wheel ;' are movable to and fro in slots, as usual, so that 
 they may expand or contract (as it were) in proportion to the lay of the strand or rope. On the axis 
 k of the wheels i and/ and outside of both, there is keyed a flat grooved rigger m, which is connected 
 by a band n to a similar flat grooved rigger o, keyed on a separate shaft P, which carries a double 
 whelp-wdieel q , by which the strand or rope is carried along as it is completed. 
 
 And, secondly, my invention, in so far as it regards the fitting and using rope or cordage, has special 
 relation to the application of wire rope or cordage to the standing rigging of ships, and consists in the 
 improved contrivance for the purpose represented in the figure ; a represents the side of a vessel ; B, 
 the chain-plate ; D, a spring lanyard of the ordinary form ; / a tube, in which the lanyard is inclosed ; 
 c, a slip shackle ; e, a stud attached to the front of the tube/) and having an orifice in it, through which 
 the forelock e‘ is passed. By taking out the forelock e\ and pulling down the tube/, the shackle slips 
 up and opens out, whereby the rope can be instantly disengaged as may be required. 
 
 WIRING MACHINE, for the manufacture of tin , sheet-iron, and other plate-ware — Patented by A. 
 W. Whitney, Woodstock, Vermont, 1817. 
 
 The face-plates or rolls HIP are made of cast-steel of an improved form, having the journal-boxes of 
 their shafts in a cast-iron frame. This frame consists of two pieces, fitted together at A, and at the top 
 of the upright piece under K. The journal-box A has 
 two projecting ears or bearings, (one of which is seen 
 at A,) at right angles to the shaft B H, on which ears 
 it is supported, forming a fulcrum to the shaft B H ; 
 thus preserving the bearing of the shaft A perfect, 
 while the end H is raised and depressed in the process 
 of working. B is a movable collar for adjusting the 
 shaft and rolls longitudinally, with great nicety. C 
 is a binding screw for keeping the collar in place. In 
 the shaft concealed by the collar B, is a spiral groove, 
 into which the binding screw enters. Thus, by turn- 
 ing the collar on the shaft, a nice longitudinal adjust- 
 ment can readily be obtained. The movement of the 
 rolls H H is secured in the usual manner by the con- 
 necting geering G G. F is a gage extending between 
 the rolls, with a spring F, and a thumb-nut L, for ad- 
 justment. I is a forming gage, consisting of a friction 
 roll attached to the side of a short rod or shaft, and 
 having its journal bearing in the frame. On the inner 
 end of this shaft is a ratchet-wheel N, for placing the gage in any desired position. Fitted to the ratch- 
 et is a latch E for holding it in place. At D is a spring, pressing the latch into the teeth of the ratchet. 
 
 In the working of the machine the bearing at A always remains perfect ; for its journal-box, by turn- 
 ing on its ears, accommodates itself to the shaft in all positions. Again, the inclination of the shaft B H 
 is always towards H, so as to bring the collar B in contact with the box. Now to compensate for any 
 wear which may displace the rolls HH, as well as to adjust them to different kinds of work, the collar 
 B is always immediately adequate. 
 
 It will readily be seen that the above improvements secure advantages not possessed by any former 
 construction, rendering the machine susceptible of immediate adaptation to plates of different thickness. 
 
 The above improvements are applied to other machines. 
 
 WOODS, VARIETIES OF, used in the Mechanical Arts . — By far the most numerous and important 
 ot the materials from the vegetable kingdom are the woods, with which most parts of our globe are 
 abundantly supplied ; great numbers of them are used in their respective countries, and are known to 
 the naturalist, although but a very inconsiderable portion of them are familiar to us in our several local 
 practices. 
 
 The woods that are most commonly employed in this country are enumerated in an alphabetical 
 list, together with the most authentic information obtainable concerning them. 
 
 The general understanding of the principal differences of the woods will be greatly assisted by a 
 brief examination into their structure which is now so commonly and beautifully developed by the sec- 
 tions for the microscope. The Figs. 3928, 3929, 3930 are drawn from thin cuttings of beech-wood, 
 prepared by the optician for that instrument: the principal lines alone are represented, and these are 
 magnified to about twice their linear distances, for greater perspicuity. 
 
 Fig. 3928, which represents the horizontal or transverse section of a young tree or a branch, shows 
 the arrangement of the annual rings around the centre or pith ; these rings are surrounded by an ex- 
 terior covering, consisting also of several thinner layers, which it will suffice to consider collectively, in 
 their common acceptation, or as the bark. The fibres which are seen as rays proceeding from the pith 
 to the bark, are the medullary rays or plates. 
 
a 16 
 
 WOODS, VARIETIES OF. 
 
 Fig9. 3929 and 3930 are vertical sections of an older piece of beech-wood. Fig. 3929 is cut through 
 a plane, such as from a to a, in which the edges of the annual rings appear as tolerably parallel fibres 
 running in one direction, or lengthways through the stem ; the few thicker stripes gu'e the edges o> 
 6ome of the medullary rays. 
 
 Fig. 3930 is cut radially, or through the heart, as from b to b. In this the fibres are observed to be 
 arranged in two sets, or to run crossways ; there are, first, the edges of the annual rings, as in Fig. 3929 ; 
 and, secondly, the broad medullary rays or plates. 
 
 The whole of these figures, but especially the last, show the character of all the proper woods, namely, 
 those possessing two sets of fibres, and in which the growth of the plant is accomplished, by the yearly 
 addition of the external ring of the wood, and the internal ring of the bark, whence these rings are 
 called annual rings, and the plants are said to be exogenous, from the growth of the wood being external. 
 
 In Fig. 3928 the medullary rays are the more distinctly drawn, in accordance with the appearance of 
 the section, as they seem to constitute more determinate lines ; whereas the annual rings consist rather 
 of series of tubes arranged side by side, and in contact with each other, and which could not be repre- 
 sented on so small a scale. At the outer part of each annual ring these tubes or pores appear to be 
 smaller and closer ; the substance is, consequently, more dense, from the greater proportion of the mat- 
 ter forming the walls of the tubes ; and the inner or the softer parts of the annual rings have in general 
 larger vessels, and therefore less density. 
 
 In many plants the wedge-form plates, intermediate between the medullary rays, only appear as an 
 irregular cellular tissue full of small tubes or pores, without any very definite arrangement* The me- 
 dullary rays constitute, however, the most characteristic part of the structure, and greatly assist in 
 determining the difference between the varieties of the exogenous plants, as well as the wide distinc- 
 tion between the entire group and those shortly to be described. The medullary rays also appear, by 
 their distinct continuity, to constitute the principal source of combination and strength in the substance 
 of the woods ; most of the medullary rays, in proceeding from the centre to the circumference, divide 
 into parts to fill out the increased space. 
 
 In the general way, the vertical fibres of the annual rings, and the horizontal fibres of the medullary 
 rays, are closely and uniformly intermingled ; they form collectively the substance of the wood, and 
 they also constitute two series of minute interstices, that are viewed to be either separate cells or ves- 
 sels, the majority of which proceed vertically, the others radially. In many, as the oak, sycamore, 
 maple, and sweet chestnut, the medullary rays, when dissected, exhibit a more expanded or foliated 
 character, and pervade the structure, not as simple radial tubes, but as broad septa or divisions, which 
 resemble flattened cells or clefts amongst the general groups of pores, giving rise to the term silver- 
 grain, derived from them light and glossy appearance : they vary considerably in size and number. 
 
 The beech-wood, Fig. 3930, has been selected as a medium example between this peculiarity and the 
 ordinary crossings of the fibres, which in the firs and several others seem as straight as if they were 
 lines mechanically ruled, and, even in the most dense woods, are in general easily made out under the 
 microscope. 
 
 The vessels or cells running amidst the fibres are to the plant what the blood-vessels and air-cells 
 are to the animal ; a part of them convey the crude sap from the roots, or the mouths of the plant, 
 through the external layers of the wood to the leaves, in which the sap is evaporated and prepared ; 
 the fluid afterwards returns through the bark as the elaborated sap, and combines with that in the ex- 
 ternal layers of the wood, the two constituting the cambium. The latter ultimately becomes consoli- 
 dated for the production of the new annual ring that is deposited beneath the loosened bark, and which 
 is eventually to constitute a part of the general substance or wood ; the bark also receives a minute 
 addition yearly, and the remainder of the fluid returns to the earth as an excretion. f 
 
 The other order of the plants grows in an entirely different manner, namely, by a deposition from 
 within, whence they are said to be endogenous ; these include all the grasses, bamboos, palms, d:c. 
 Endogens are mostly hollow, and have only one set of fibres, the vertical, which appear in the trans- 
 verse section, Fig. 3931, as irregular dots closely congregated around the margin, and gradually more 
 distant towards the centre, until they finally disappear, and leave a central cavity, or a loose cellular 
 structure. Fig. 3932 represents the horizontal, and Fig. 3933 the vertical section of portions of the 
 same, or the cocoanut palm (Cocos nucifera) of half their full size. 
 
 * In the Cissampctos Pwrcira, belonging to the natural order Menispcrmaceae, this structure is singularlv evident; the 
 medullary rays are very thick, and almost detached from the intermediate wedge-form plates, which are nearly solid, 
 except the few pores by which they are pierced, much like the substance of the common cane. 
 
 f The reader is referred to the following articles in the three editions of Dr. Lindley’s Introduction to Botany, namely, 
 “ Exogenous structure and Of the stem and origin of wood and also, u Exogens and u Endogens, ” by the same 
 Wthor, in the Penny Cyclopaedia; all are replete with physiological interest. 
 
WOODS, VARIETIES OF. 
 
 917 
 
 All the endogens are considered to commence from a circular pithy stem, which is entirely solid 
 some, as the canes, maintain this solidity, with the exception of the tubes or pores extending through 
 out their length. The bamboos extend greatly in diameter, so as to become hollow, except the dia 
 phragms at the knots ; these are often used as cases for rolls 
 of papers. The palms generally enlarge still more consider- 
 ably to their extreme size, which, in seme cases, is fifty times 
 the diameter of the original stem, the centre being soft and 
 pithy. 
 
 Some of the palms, &c., denote each yearly increase by one 
 of the rings or markings upon their stems, which are always 
 soft in the upper part, like a green vegetable, and terminate 
 in a cluster of broad pendent leaves, generally annual, and 
 when they drop off they leave circular marks upon the stem, 
 which are sometimes permanent, and indicate by their num- 
 ber the age of the plant. The vertical fibres above referred 
 to proceed from the leaves, and are considered to be analogous 
 to their roots, and likewise to assimilate in function to the 
 downward flow of the sap from the leaves of the exogens : 
 whereas in the palms they constitute separate and detached 
 fibres, that first proceed inwards, and then again outwards, 
 with a very long and gradual sweep, thereby causing the 
 fibres to be arranged in part vertically, and in part inclined, 
 as in the figure.* 
 
 The substance of the stems of the palms is not allowed by 
 physiological botanists to be proper wood, (which in all cases 
 grows exteriorly, and possesses the two sets of fibres shown 
 in Fig, 3930,) whereas the endogenous plants have only the one 
 set, or the vertical fibres ; and although many of this tribe 
 yield an abundance of valuable gifts to the natives of the trop- 
 ical climates in which they flourish, only a portion of the lower 
 as wood ; amongst other purposes, the smaller kinds are used by the natives as tubes for the convey- 
 ance of water, and the larger pieces as joists and beams. 
 
 The larger palms generally reach us in slabs measuring about the sixth or eighth part of the circle, 
 as in Fig. 3931, the smaller sizes are sent entire; Fig. 3932 represents a small piece near the outside, 
 with the fibres half size ; but the different palms vary considerably in the shapes, magnitudes, and dis- 
 tances of the fibres, and the colors and densities of the two parts. 
 
 In the vertical section, Fig. 3933, which is also drawn half size, the fibres look like streaks or wires 
 imbedded in a substance similar to cement or pith, which is devoid of fibrous structure. The inhab- 
 itants of the Isthmus of Darien pick out the fibres from some of the palms and use them as nails ; they 
 are generally pointed, and in the specimens from which the drawing was made, they are as hard as 
 rosewood, whereas the pithy substance is quite friable. Some of the smallest palms are imported 
 into this country for walking-sticks, under the names of partridge and Penang canes, <fcc. The ordi- 
 nary canes and bamboos are too well known to require more than to be named. 
 
 To return to the more particular examination of the woods that most concern us, it will be observed 
 that the central pith in Fig. 3928 happens to be of an irregular triangular shape. This, the primary 
 portion of the plant, is, in the first instance, always cylindrical ; it is supposed to assume its accidental 
 form (which is very frequently hexagonal) from the compression to which it is subjected. The pith 
 governs, in a considerable degree, the general figure or section, as all the series of rings will be ob- 
 served, in Fig. 3928, to have a disposition to project at three points ; but with the successive additions, 
 the angular form is gradually lost, as it would be if we wound a ribbon upon a small triangular wire ; 
 for, after a time, no material departure from the circular form would be observable. 
 
 A greater variation amongst the rings is due to the more or less favorable growth of the successive 
 years, and to the different exposure of the tree to thevsun and air, which develop that side of the plant 
 in an additional degree ; whereas the tree growing against a wall or any other obstruction, becomes 
 remarkably stunted on that side of its axis, from being so shielded. 
 
 The growth of a tree is seldom so exactly uniform that is section is circular, or its heart central ; 
 often far from it ; and as every annual ring is more consolidated, and of a deeper color on its outer sur- 
 face, they frequently serve to denote very accurately, in the woods growing in cold and temperate cli- 
 mates, the age of the plant, the differences of the seasons, the circumstances of its situation, and the 
 general rapidity of its growth. “ But in many hot countries the difference between the growing season 
 and that of rest, if any occur, is so small, that the zones are as it were confounded, and the observer 
 finds himself incapable of distinguishing with exactness the formation of one year from that of another.” f 
 
 It is, however, difficult to arrive at any satisfactory conclusion respecting the qualities of woods, 
 from the appearance of their annual rings ; for instance, in two specimens of larch, considered by Mr. 
 Finchamj; to be exceedingly similar, in specific gravity, strength, and durability ; in the one, Scotch 
 larch, there were only three annual rings in five-eighths of an inch, whereas in Italian larch there were 
 twenty-four layers in the same space. In some of the tropical woods the appearance of the rings can 
 scarcely be defined, and in a specimen of the lower or butt-end of teak, now before us, three annual 
 rings alone cover the great space of one inch and three-eighths. 
 
 part of the shell of the tree is available 
 
 * The leaves of the exogens are by some thought to send down similar roots or fibres between the bark and wood foi 
 the formation of the annual ring. t Dr. Lindley’s Introduction to Botany, second edition, p. 74. 
 
 t Principal builder of the Chatham Dock-yard, England, and a writer on ship-h’iilding. 
 
918 
 
 WOODS, VARIETIES OF. 
 
 The horizontal section of a tree occasionally looks as if it were the result of two, three, or more sepa- 
 rate shoots or stems consolidated into one ; in some of the foreign woods in particular this irregularity 
 often gives rise to deep indentations, and most strange shapes, which become eventually surrounded by 
 one single covering of sap ; so that a stem of considerable girth may yield only an insignificant piece 
 of wood, scarcely available for the smallest purposes of turnery, much less for cabinet-work.* 
 
 The circulation of the sap is considered to be limited to a few of the external layers, or those of the 
 sap-wood, or alburnum , which are in a less matured state than the perfect wood, or duramen, beneath 
 The last act of the circulation, as regards the heart-wood, is supposed to be the deposition of the 
 coloring matter, resin or gum, through the agency of the medullary rays that proceed from the bark 
 towards the centre, and leave their contents in the layer outside the true wood perfected the year pre- 
 vious. We may fairly suppose by analogy, that as one ring is added eacli year, so one is perfected 
 annually, and thrown out of the circulatory system. 
 
 That the circulation has ceased in the heart-wood, and that the connection between it and the bark 
 has become broken, is further proved by the fact, that numbers of trees may be found in tolerably 
 vigorous growth within the bark, whereas at the heart they are decayed and rotten. In fact, some of 
 the hardest foreign woods, as kingwood, tulip-wood, and others, are rarely sound in the centre, and 
 thus indicate very clearly that their decay commenced whilst they were in their parent soil ; and as in 
 these the appearance of annual rings is scarcely to be distinguished, this also appears to indicate a 
 great term of age, enough to account for this relatively premature decay. 
 
 The quantity of sap-wood is various in different plants, and the line of division is usually most 
 distinctly marked; in some, as boxwood, the sap-wood is very inconsiderable, and together with the 
 bark is on the average only about the thickness of a stout card, whereas in others, as the snakewood, 
 it constitutes fully two-thirds of the diameter, so that a large tree yields but an inconsiderable stick of 
 wood, of one-third or fourth the external diameter. 
 
 It may be presumed that, in the same variety of wood, about an average number of the layers exist 
 as sap-wood, as in cutting up a number of pieces of the same kind, such as the black Botany-Bay wood, 
 and others, it is found that, in those measuring about two inches diameter, the piece of heart-wood is 
 only about as large as the finger, but in pieces one, two, or three inches larger, the heart-wood is also 
 respectively one, two, or three inches larger, or nearly to the full extent of the increase of the diameter. 
 
 The sap-wood may be therefore, in general, considered as of about an average thickness in each kind 
 of wood : it is mostly softer, lighter, more even in color, and more disposed to decay than the heart-wood, 
 which prove it to be in a less matured or useful state, whether for mechanical or chemical purposes. 
 
 At the time the tree is separated from its root, its organic life cease?, and then commences the 
 gradual evaporation of the sap, and the drying and contracting of the tubes, or tissues, previously 
 distended by its presence. 
 
 The woods are in general felled during the cold months, when the vegetative powers of the plant are 
 (.early dormant, and when they are the most free from sap ; but none of the woods are fit for use in the 
 state in which they are cut down, for although no distinct circulation is going on within the heart-wood, 
 still the capillary vessels keep the trees continually moist throughout their substance, in which state 
 they should not be employed. 
 
 If the green or wet woods are placed in confined situations, the tree or plank first becomes stained or 
 doated, and this speedily leads to its decomposition or decay, effects that are averted by careful drying 
 with free access of air.f 
 
 Other mischiefs almost as fatal as decay also occur to unseasoned woods ; round blocks cut out of the 
 entire circular stem of green wood, or the same pieces divided into quarterings, split in the direction of 
 the medullary rays, or radially, also, though less frequently, upon the annual rings. Such of the round 
 blocks as consist of the entire section contract pretty equally, and nearly retain their circular form, but 
 those from the quarterings become oval from their unequal shrinking. 
 
 * This is not peculiar to the tropical woods; for example, some of the yew-trees in Hampton Court gardens appear to 
 have grown in this manner from three or lour separate stems, that have joined into one at a short distance above the 
 ground. As an instance of the singular manner in which the separate branches of trees thus combine, I may mention that 
 stones, pieces of metal, and other substances, are occasionally met with in the central parts of timber, from having been 
 accidentally deposited in a cleft, or the fork of a branch, and entirely inclosed or overgrown by the subsequent increase ot 
 the plant. 
 
 f On this account the timbers for ships are usually cut out to their shape and dimensions for about a year before they 
 are framed together, and they are commonly left a twelvemonth longer in the skeleton state, lo complete ihe seasoning, as 
 in that condition they are more favorably situated as regards exposure to the air than when they are closely covered in with 
 the planking. 
 
 Sir. Fincham considers that the destruction of timber by the decay commonly known as dry-rot cannot occur, unless air, 
 moisture, and heat, are all present, and that the entire exclusion of any of the three stays the mischief. By way of experi- 
 ment, he bored a hole in one of the timbers of an old ship, built of oak, whose wood was at the time perfectly sound ; the 
 admission of air, the third element, to the central par t of the wood, (the two olhers being to a certain degree present,) 
 caused the hole to be filled up in the course of twenty-four hours with mouldiness, a well-known vegetation, which very 
 speedily became so compact a fungus as to admit of being withdrawn like a slick. He considers the shakes or splits in 
 Umber to predispose it to decay, in damp and confined situations, from admitting the air in the same manner. 
 
 The woods differ amazingly in their resistance to decay ; some perish in one or two years, whereas others are very durable, 
 and even preserve their fragrance when they are opened afier many years, or almost centuries. 
 
 Mr. G. Loddiges says the oak-boxes, for the plants in his green-houses, decay in two or three years, whereas he has found 
 jhoso of teak to last fully six or seven times as long: the situation is one of severe trial for the wood. 
 
 There are two quarto works on dry-rot; the one by Mr. Me William, 1818; the other by Mr. John Knowles, Surveyor o 1 
 Her Majesty’s Navy, 1821. 
 
 The process of Kyanizing is intended to prevent the re-vegetation of timber, by infusing into its pores an antiseptic salt : 
 the corrosive sublimate is generally employed, other metallic salts are also considered to be applicable, but the general 
 utility of the process, especially in thick timbers, or those exposed to much wet, is still unsettled amongst practical men. 
 
 The Kyanizing is sometimes done in open tanks, at others, (by Timperley’s process, Hull and Selby Railway,) in close 
 vessels from which the air is first exhausted to the utmost, and the fluid is then admitted under a pressure of about 10(1 
 pounds on the inch. 
 
WOODS, VARIETIES OF. 
 
 919 
 
 As a general observation, it may be said the tvoods do not alter in any material degree in respect tc 
 length. Boards and flat pieces contract, however, in width, they warp and twist, and when they are 
 fitted as panels into loose grooves, they shrink away from that edge which happens to be the most 
 slightly held ; but when restrained by nails, mortises, or other unyielding attachments, which do not 
 allow them the power of contraction, they split with irresistible force, and the materials and labor tho. 
 improperly employed will render no useful service. 
 
 In general, the softest woods shrink the most in width, but no correct observations on this subject 
 have been published. Mr. Fincham considers the rock-elm to shrink as much as any wood, namely, 
 about half an inch in the foot, whereas the teak scarcely shrinks at all ; in the “ Tortoise” store-ship, 
 when fifty years old, no openings were found to exist between the boards. 
 
 In the woods that have been partially dried, some of these effects are lessened when they ar u 
 , defended by paint or varnish, but they do not then cease, and, with dry wood, every time a new surface 
 is exposed to the air, even should the work have been made for many years, these perplexing alterations 
 will in a degree recommence, even independently of the changes of the atmosphere, the fluctuations of 
 which the woods are at all times too freely disposed to obey. 
 
 The disposition to shrink and warp, from atmospheric influence, appears indeed to be never entirely 
 subdued ; some bog-oak, supposed to have been buried in the island of Sheppy not less than a thousand 
 years, was dried for many months, and ultimately made into chairs and furniture ; it was still found to 
 shrink and cast, when divided into the small pieces required for the work. 
 
 Seasoning and preparing the woods. — Having briefly alluded to the mischiefs consequent upon the 
 use of woods in an improper condition, I shall proceed to describe the general modes pursued for avoiding 
 such mischiefs by a proper course of preparation : 
 
 The woods, immediately after being felled, are sometimes immersed in running water for a few days, 
 weeks, or months, at other times they are boiled or steamed ; this appears to be done under the expec- 
 tation of diluting and washing out the sap, after which it is said the drying is more rapidly and better 
 accomplished, and also that the colors of the white woods are improved, (see article Holly in Catalogue, 
 also Ebony ;) but the ordinary course is simply to expose the logs to the air, the effect of which is assisted 
 by the preparation of the wood into smaller pieces, approaching to the sizes and forms in which they 
 will be ultimately used, such as square logs and beams, planks or boards of various thicknesses, short 
 lengths or quarterings, <ftc. 
 
 The stems and branches of the woods of our own country, such as alder, birch, and beech, that are 
 used by the turner, frequently require no reduction in diameter; but when they are beyond the size of 
 the work, they are split into quarterings and stacked in heaps to dry, which latter proceeding should 
 never be forgotten under any circumstances. 
 
 We know but little of the early treatment of the foreign woods used for cabinet-work and turning ; 
 some few of them, as mahogany and satin-wood, are imported in square logs ; others, as rosewood, 
 ebony, or Coromandel, are sometimes shipped in the halves of trees, or in thick planks ; but the general- 
 ity of those used for turning are small, and do not require this reduction ; these only reach us in billets, 
 sometimes with the rind or bark upon them, and sometimes cleaned or trimmed. 
 
 The smaller hard woods are very much more wasteful than the timber woods ; in many of the former, 
 independently of their thick bark, the section is very far from circular, as they are often exceedingly 
 irregular, indented, and ill-defined ; others are almost constantly unsound in their growth, and eithei 
 present central hollows and cavities, or cracks and radial divisions, which separate the stem into three 
 or four irregular pieces. 
 
 Probably none of the hard woods are so defective as the black Botany-Bay wood, in which the 
 available produce, when it is trimmed ready for the lathe, may be considered to be about one-third or 
 fourth of the original weight, sometimes still less ; but unfortunately many others approach too nearly 
 to this condition, as a very large proportion of them partake of the imperfections referred to, more 
 especially the cracks ; the larger hard woods are by comparison much less wasteful. 
 
 All the harder woods require increased care in the seasoning, which is often badly begun by exposure 
 to the sun or hot winds in their native climates : their greater impenetrability to the air the more 
 disposes them to crack, and their comparative scarcity and expense are also powerful arguments on 
 the score of precaution. It is therefore desirable to prepare them for the transition from the yard or 
 cellar to- the turning-room, by removing the parts which are necessarily wasted, the more intimately to 
 expose them to the air some time before they are placed in the house, and they should be always kept 
 away from the fire, or at first in a room altogether without one. 
 
 It is usual to begin by cutting the logs into pieces a few inches or upwards in length, to the general 
 size of the work ; and if possible to prepare every piece into a round block, or into two or three, when 
 the wood is irregular, hollow, or cracked. In the latter case, a thin wedge is inserted into the principal 
 crack, and driven down with a wooden maul ; or a cleaver which has a sharp edge, and a poll to receive 
 the blow, is used in the same manner ; these tools, or the hatchet, are likewise used in splitting up the 
 English woods, when they are beyond the diameters required.* The cleft pieces are next roughly 
 trimmed with the hatchet, or else with the paring-knife, a tool of safer and more economical application 
 in the hands of the amateur : it is a lever knife, from two and a half to three feet long ; the cutting-edge 
 is near that end which terminates in a hook, the other extremity has a transverse handle ; an eye-bolt 
 for the hook to act against is screwed into the bench or block, and a detached cutting-board is fixed 
 under the blade, to serve as the support for the wood, and for the knife to cut upon. To avoid waste 
 of material, it is advisable, until the eye is well accustomed to the work, to score with the compasses 
 upon each end of the rough block as large a circle as it will allow, to serve as a guide for the knife. 
 
 The block is adapted to the bearers of the lathe, but any other support will serve equally well. The 
 paring-knife is also employed for other purposes besides those of the turner : it is sometimes made with 
 
 * Sometimes the. glazier’s chipping knife is used for small pieces of wood instead of the cleaver. 
 
920 
 
 WOODS, VARIETIES OF. 
 
 a curved edge like a gouge, and is used in many shaping operations in wood, as in the manufacture of 
 shoe-lasts, clogs, pattens, and toys.* * * § 
 
 In the absence of the paring-knife or hatchet, the work is fixed in the vice, and rounded with a coarse 
 rasp, but this is much less expeditious : by some manufacturers the preparation botli of the foreign and 
 English woods is prosecuted still further, by cutting the material into smaller pieces, rough turned and 
 hollowed in the lathe, to the forms of boxes, or other articles for which they are specifically intended ; 
 and in fact every measure that tends to make the change of condition gradual, assists also in the 
 economy, perfection, and permanence of the work. 
 
 Many of the timber-woods are divided at the saw-pit into planks or boards, at an early stage, in order 
 to multiply the surfaces upon which the air may act, and also to leave a less distance for its penetration : 
 after sawing, they should never be allowed to rest in contact, as the partial admission of the air often 
 causes stains or doating ; but they are placed either perpendicularly or horizontally in racks, or they 
 are more commonly stacked in horizontal piles, with parallel slips of wood placed between at distances 
 from about three to six or eight feet, according to the quantity of support required ; the pile when 
 carefully stacked forms a press, and keeps the whole flat and straight. 
 
 Thin pieces will be sufficiently seasoned in about one year’s time, but thick wood requires two or 
 three years, before it is thoroughly fit to be removed to the warmer temperature of the house for the 
 completion of the drying. Mahogany, cedar, rosewood, and the other large foreign woods, require to 
 be carefully dried after they are cut into plank, as notwithstanding the length of time that sometimes 
 intervenes between their being felled and brought into use, they still retain much of their moisture whilst 
 they remain in the log.f 
 
 In some manufactories the wood is placed, for a few days before it is worked up, in a drying-room 
 heated by means of stoves, steam, or hot water, to several degrees beyond the temperature to which the 
 finished work is likely to be subjected. 
 
 Such rooms are frequently made as air-tight as possible, which appears to be a mistake, as the wood 
 is then surrounded by a warm but stagnant atmosphere, which retains whatever moisture it may have 
 evaporated from the wood. Of late, a plan has been more successfully practised in seasoning timber 
 for building purposes, by the employment of heated rooms with a free circulation of air, which enters 
 at the lower part in a hot and dry state, and escapes at the upper charged with the moisture, which it 
 freely absorbs in the heated condition. The continual ingress of hot dry air, greedy of moisture, so far 
 expedites the drying, that it is accomplished in one-third of the time that is required in the ordinary 
 way in the open air.j: 
 
 Hard and soft woods, etc . — The relative terms hard and soft, elastic or non-elastic, and the proportions 
 of resins, gums, <fcc., as applied to the woods, appear to be in a great measure explained by their exam- 
 ination under the microscope, which develops their structure in a very satisfactory manner. 
 
 The fibres of the various woods do not appear to differ so materially in individual size or bulk, as in 
 their densities and distances : those of the soft woods, such as willow, alder, and deal, appear slight 
 and It. >se ; they are placed rather wide asunder, and present considerable intervals for the softer and 
 more s longy cellular tissue between them ; whereas in oak, mahogany, ebony, and rosewood, the fibres 
 appeal rather smaller, but as if they possessed a similar quantity of matter, just as threads containing 
 the same number of filaments are larger or smaller, accordingly as they are spun. The fibres are also 
 more closely arranged in the harder woods, the intervals between them are necessarily less, and the 
 whole appears a more solid and compact formation. 
 
 The very different tools used by the turner for the soft woods and hard woods respectively, may have 
 assisted in fixing these denominations as regards his art ; a division that is less specifically entertained 
 by the joiner, who uses the same tools for the hard and soft woods, excepting a trifling difference in 
 their angles and inclinations ; whereas the turner employs, for the soft woods, tools with keen edges of 
 thirty or forty degrees, applied obliquely, and as a tangent to the circle ; and for the hard woods, tools 
 of from seventy to ninety degrees upon the edge, applied as a radius, and parallel with the fibres, if so 
 required. The tools last described answer very properly for the dense woods, in which the fibres are close 
 and well united ; but applied to the softer kinds, in which the filaments are more tender and less firmly 
 joined, the hard-wood tools produce rough, torn, and unfinished surfaces. 
 
 In general, the weight or specific gravity of the woods may be taken as a sure criterion of their 
 hardness ; for instance, the hard lignum-vitre, boxwood, iron-wood, and others, are mostly so heavy as to 
 sink in water ; whereas the soft firs, poplar, and willow, do not, on the average, exceed half the weight 
 of water, and other woods are of intermediate kinds.§ 
 
 * A paring-knife working in a guide, and with an edge twelve or fourteen inches long, i9 a most effective instrument in 
 the hands of the toy-makers. The pieces of birch, alder, &c., are boiled in a cauldron for about an hour to soften them, 
 and whilst hot they may be worked with great expedition and perfection. The workmen pare off slices, the plankway of 
 the grain, as large as four by six inches, almost as quickly as they can be counted: they are wedged tight in rows, like 
 books, to cause them to dry tint and straight, and they seldom require any subsequent smoothing. In making the little 
 wheels for carts, &c., say of one or two inches diameter, and one-quarter or three-eighths of an inch thick, they cut them 
 the cross-way of the grain , out of cylinders previously turned and bored ; the flexibility of the hot moist wood being such 
 that it yields to the edge of the knife, without breaking transversely as might be expected. 
 
 t Scientifically considered, the drying is only said to be complete when the wood ceases to lose weight from evaporation : 
 this does not occur after twice or thrice the period usually allowed for the process of seasoning. 
 
 In many modern buildings small openings are left, through the walls to the external air, to allow a partial circulation 
 amidst the beams and joists, as a preservative from decay, and for the entire completion of the seasoning. 
 
 X Price’s Patent. 
 
 § The most dense wood is the Iron Hark wood from New South Wales: in appearance it resembles a close hard ma- 
 hogany, but more brown than red ; its specific gravity is P420, — its strength (compared with English oak, taken as usual at 
 1*000) is l'5o7. On the other hand, the lightest of the true woods is probably the Cortica , or the el none palustris , from 
 Brazil, in Mr. Mier’s collection ; the specific gravity of this is only 0*206, whereas that of cork is 0*240 ; it has only one- 
 seventh the weight of Iron Bark wood. The Cortica resembles ash in color and grain, except that it is pale.', finer, and 
 much softer ; it is used by the natives lor wooden shoes. &.c. 
 
WOODS, VARIETIES OF. 
 
 9liJ 
 
 The density or weight of many of the woods may be increased by their mechanical compression, 
 which may be carried to the extent of fully one-third or fourth of their primary bulk, and the weight 
 and hardness obtain a corresponding increase. This has been practised for the compression of tree-nails 
 for ships, by driving the pins through a metal ring smaller than themselves directly into the hole in tho 
 ship’s side •* * * * § at other times, (for railway purposes,) the woods have been passed through rollers, but 
 this practice has been discontinued, as it is found to spread the fibres laterally, and to tear them 
 asunder ;f an injury that does not occur when they are forced through a ring, which condenses the wood 
 at all parts alike without any disturbance of its fibrous structure,! even when tested by the microscope ; 
 after compression, the wood is so much harder that it cuts very differently, and the pieces almost ring 
 when they are struck together ; fir may be thus compressed into a substance as close as pitch-pine. 
 
 In many of the more dense woods, we also find an abundance of gum or resin, which fills up many of 
 those spaces that would be otherwise void : the gum not only makes the wood so much the heavier, but 
 at the same time it appears to act in a mechanical manner, to mingle with the fibres as a cement, and 
 to unite them into a stronger mass ; for example, it is the turpentine that gives to the outer surface of 
 the annual rings of the red and yellow deals the hard, horny character, and increases the elasticity of 
 those timbers. 
 
 Those woods which are the more completely impregnated with resin, gum, or oil, are in general also 
 the more durable, as they are better defended from the attacks of moisture and insects. 
 
 Timbers alternately exposed to wet and dry, are thought, by Tredgold and others, to suffer from 
 losing every time a certain portion of their soluble parts ; if so, those which are naturally impregnated 
 with substances insoluble in water may, in consequence, give out little or none of their component parts 
 in the change from wet to dry, and on that account the better resist decay : this has been artificially 
 imitated by forcing oil, tar, <fcc., through the pores of the wood from the one extremity.^ 
 
 Many of the woods are very durable when constantly wet ; the generality are so when always dry, 
 although but few are suited to withstand the continual change from one to the other state ; but these 
 particulars, and many points of information respecting timber-woods that concern the general practice 
 of the builder, or naval architect, such as their specific gravities, relative strengths, resistances to bending 
 and compression, and other characters, are treated of in Tredgold’s Elements of Carpentry, at consider- 
 able length. || 
 
 Elastic and non-elastic woods. — The most elastic woods are those in which the annual or longitudinal 
 fibres are the straightest, and the least interwoven with the medullary rays, and which are the least 
 interrupted by the presence of knots; such woods are also the most easily rent, and the plainest in fig- 
 ure, as the lancewood, hickory, and ash ; whereas other woods, in which the fibres are more crossed and 
 interlaced, are considerably tougher and more rigid ; they are also less disposed to split in a straight or 
 economical manner, as oak, beech, and mahogany, which, although moderately elastic, do not bend with 
 the facility of those before named. 
 
 Eishing-rods, unless made of bamboo, have generally ash for the lower joint, hickory for the two mid- 
 dle pieces, and a strip cut out of a bamboo of three or four inches diameter as the top joint. Archery 
 bows are another example of elastic works ; the “ single-piece bow” is made of one rod of hickory, lance- 
 wood, or yew-tree, which last, if perfectly free from knots, is considered the most suitable wood : the 
 “ back or union bow” is made of two or sometimes three pieces glued together. The back-piece , or that 
 furthest from the string, is of rectangular section, and always of lancewood or hickory ; the belly , which 
 is nearly of semicircular section, is made of any hard wood that can be obtained straight and clean, as 
 ruby-wood, rosewood, greenheart, kingwood, snakewood, and several others : it is in a great measure a 
 matter of taste, as the elasticity is principally due to the back-piece ; the palmyra is also used for bows.^j 
 
 The elasticity, or rather the flexibility of the woods, is greatly increased for the time, when they are 
 heated by steaming or boiling ; the process is continually employed for bending the oak and other tim- 
 bers for ship-building, the lancewood shafts for carriages, the staves of casks, and various other works. 
 
 The woods are steamed in suitable vessels, and are screwed or wedged, at short intervals throughout 
 their length, in contact with rigid patterns or moulds, and whilst under this restraint they are allowed 
 to become perfectly cold ; the pieces are then released. These bent works suffer very little departure 
 from the forms thus given, and they possess the great advantage of the grain being parallel with the 
 curve, which adds materially to their strength, saves much cost of material and time in the preparation, 
 and gives, in fact, a new character to the timber. 
 
 The inner and outer plankings of ships are steamed or boiled before they are applied ; they are 
 brought into contact with the ribs by temporary screw-bolts, which are ultimately replaced by the cop- 
 
 Th'e Pita wood, that of the Fourcroya gigantea , of the Brazils, an cmlogen almost. like pith, fused by the fishermen of 
 Rio Janeiro, as a slow match, for lighting cigars, &c. ; also like cork for lining the drawers of cabinets for insects,) and the 
 rice-paper plant of India and China, which is still lighter and more pithy, can hardly be taken into comparison. 
 
 * Sir. Aunersley’s Patent, 1821, for building vessels of planks only, without ribs. 
 
 f Dublin and Kingston Railway. 
 
 j The mode at present practised by the Messrs. Ransome, of Ipswich, (under their patent.) is to drive the pieces of oak 
 Into an iron ring by means of a screw-press, and to expose them within the ring to a temperature of about 180° for twelve 
 or sixteen hours before forcing them out again. 
 
 The tree-nails may be thus compressed into two-thirds their original size, and they recover three-fourths of the compres- 
 sion on being wetted; they are used for railway purposes, but appear equally desirable for ship-building, in which the 
 tree-nails fulfil an important office, and in either case their after-expansion fixes them most securely. 
 
 § The durability of pitch pine, when “wet and dry,” is however questioned. 
 
 J The work contains a variety of the most useftd tables. 
 
 ®] The union bow is considered to be “softer,” that is, more agreeably elastic than the single-piece bow. even when the 
 wo require the same weight to draw them to the length of the arrow. In the act of bending the bow the back is put into 
 tension, and the inner piece into a state of compression, and each wood is then employed in its most suitable manner. 
 Sometimes the union bow is imitated by one solid piece of straight cocoa-wood, (of the West Indies, not that, of the cocna- 
 n ■ t palm,) in which case the tough fibrous sap is usr d for the back, and in its nature sufficiently resembles t ht lancewood 
 m ire generally used. 
 
922 
 
 WOODS, VAKIETIES OF. 
 
 per bolts inserted through the three thicknesses and riveted : or they are secured by oak or locust tree- 
 nails, which are caulked at each end.* 
 
 Boiling and steaming are likewise employed for softening the woods, to facilitate the cutting as 
 well as bending of them. I 
 
 When the two sets of fibres meet in confused angular directions, they produce the tough cross- 
 grained woods, such as lignum-vit®, elm, &c., and, like the diagonal braces in carpentry and shipping, 
 they deprive the mass of elasticity, and dispose it rather to break than to bend, especially when the 
 pieces are thin, and the fibres crop out on both sides of the same ; the confusion of the fibres is, at the 
 same time, a fertile source of beauty in appearance to most woods. 
 
 Elm is perhaps the toughest of the European woods ; it is considered to bear the driving of bolts 
 and nails better than any other, and it is on this account, and also for its great durability under water, 
 constantly employed for the keels of ships, for boat-building, and a variety of works requiring great 
 strength and exposure to wet. 
 
 A similar rigidity is also found to exist in the crooked and knotted limbs of trees from the confu- 
 sion amongst the fibres, and such gnarled pieces of timber, especially those of oak, were in former days 
 particularly valued for the knees of ships : of later years they have been in a great measure super- 
 seded by iron knees, which can be more accurately and effectively moulded at the forge to suit their 
 respective places, and they cause a very great saving in the available room of the vessel. 
 
 The liguum-vitse is a most peculiar wood, as its fibres seem arranged in moderately thick layers, 
 crossing each other obliquely, often at as great an angle as thirty degrees with the axis of the tree ; 
 when the wood is split, it almost appears as if the one layer of annual fibres grew after the manner 
 of an ordinary screw, and the succeeding layer wound the other way so as to cross them like a left- 
 hand screw. The interlacement of the fibres in lignum-vit® is so rigid and decided, although irregular, 
 that it exceeds all other woods in resistance to splitting, which cannot be effected with economy ; the 
 wood is consequently always prepared with the saw. It is used for works that have to sustain great 
 pressure and rough usage, several examples of which are given under the head Lighum-vim in the 
 Catalogue already referred to. 
 
 Fibre or grain , knots, etc . — The ornamental figure or grain of many of the woods appears to de- 
 pend as much or more upon the particular directions and mixings of the fibres, as upon their differences 
 of color. We will first consider the effect of the fibre assisted only by the slight variation of tint, ob- 
 servable between the inner and outer surfaces of the annual layers, and the lighter or more silky char- 
 acter of the medullary rays. 
 
 If the tree consisted of a series of truly cylindrical rings, like the tubes of a telescope, the hori- 
 zontal section would exhibit circles ; the vertical, parallel straight lines ; and the oblique section would 
 present parts of ovals ; but nature rarely works with such formality, and but few trees are either 
 exactly circular or straight, and therefore, although the three natural sections have a general disposi- 
 tion to the figures described, every little bend and twist in the tree disturbs the regularity of the fibres, 
 and adds to the variety and ornament of the wood. 
 
 The horizontal section, or that parallel with the earth, only displays the annual rings and medul- 
 lary rays, as in Fig. 3928 ; and this division of the wood is principally employed by the turner, as it 
 is particularly appropriate to his works, the strength and shrinking being alike at all parts of the cir- 
 cumference, in the blocks and slices cut out of the entire tree, and tolerably so in those works turned 
 out of the quarterings or parts of the transverse pieces. 
 
 But as the cut is made intermediate between the horizontal line ana the one parallel with the axis, 
 the figure gradually slides into that of the ordinary plank, magnified portions of which are shown in 
 Figs. 3929 and 3930 ; and these are almost invariably selected for carpentry, &c. 
 
 The oblique slices of the woods possess neither the uniformity of grain of the one section, nor the 
 strength of the other, and it would be likewise a most wasteful method of cutting up the timber ; it is 
 therefore only resorted to for thin veneers, when some particular figure or arrangement of the fibres has 
 to be obtained for the purposes of ornamental cabinet-work. 
 
 The perpendicular cut through the heart of the tree is not only the hardest but the most diversified, 
 because therein occurs the greatest mixture and variety of the fibres, the first and the last of which, in 
 point of age, are then presented in the same plank ; but of course the density and diversity lessen as 
 the board is cut further away from the axis. In general the radial cut is also more ornamental than the 
 tangential, as in the former the medullary rays produce the principal effect, because they are then dis- 
 played in broader masses, and are considered to contain the greater proportion of the coloring matter of 
 the wood. 
 
 The section through the heart displays likewise the origin of most of the branches, which arise first as 
 
 * See the description of Mr. William Hookey’s apparatus for bending ships’ timbers, rewarded by the Society of Arts, 
 and described in their Trans., vol. 32, p. 91. 
 
 Preference is now given to the “ Steam Kiln” over the “ Water Kiln,” and the time allowed is one hour for every inch 
 of the thickness of the timber ; it loses much extractive matter in the process, which is never attempted a second time, as 
 the wood then becomes brittle. 
 
 Colonel G. A. Lloyd devised an ingenious and economical mode of bending the timbers to constitute the ribs of a teak- 
 bridge which he built in the Mauritius. Every rib was about 180 ft. long, and of 8 ft. rise, and consisted of five thicknesses 
 of wood of various lengths and widths. The wood had been cut down about a month ; it was well steamed and brought 
 into contact with a strong mould, by means of an iron chain attached to a hook at the one extremity of the mould and 
 passed under a roller fixed at the other; the chain was drawn tight by a powerful capstan. Whilst under restraint the 
 neighboring pieces were pinned together by tree-nails, after which a further portion of the rib was proceeded with: the 
 seasoning of the timber was also effected by the process. 
 
 t Thus in Taylc 's Patent Machinery for making casks, the blocks intended for the staves are cut out of white Canada 
 oak to the size of thirty inches by five, and smaller. They are well steamed, and then sliced into pieces one-half or five- 
 eighths inch thick, at the rate of 200 in each minute, by a process far more rapid and economical than sawing; the instru- 
 ment being a revolving iron plate of 12 or 14 feet diameter, with two radial knives, arranged somewhat like tho irons of 
 Ui ordinary plane or spokeshuve. 
 
/ 
 
 WOODS, VARIETIES OF. 
 
 92c' 
 
 knots, in or near the central pith, and then work outwards in directions corresponding with the arms oi 
 the trees, some of which, as in the cypress and oak, grow out nearly horizontally, and others, as in the 
 poplar, shoot up almost perpendicularly. 
 
 Those parts of wood described as curls are the result of the confused filling in of the space between 
 the forks, or the springings of the branches. Fig. 3934 
 represents the section of a piece of yew-tree, which shows 
 remarkably well the direction of the main stem A B, the 
 origin of the branch C, and likewise the formation of the 
 curl between B and C ; Fig. 3935 is the end view of the 
 stem at A. In many woods, mahogany especially, the 
 curls are particularly large, handsome, and variegated, 
 and are generally produced as explained. 
 
 It would appear as if the germs of the primary 
 branches were set at a very early period of the growth 
 of the central stem, and gave rise to the knots, many of 
 which, however, fail to penetrate to the exterior so as to 
 produce branches, but are covered over by the more vig- 
 orous deposition of the annual rings. All these knots and 
 branches act as so many disturbances and interruptions 
 to the uniformity of the principal zones of fibres, which 
 appear to divide to make way for the passage of the off- 
 shoots, each of which possesses in its axis a filament of 
 the pith, so that the branch resembles the general trunk 
 in all respects except in bulk ; and again from the prin- 
 cipal branches smaller ones continually arise, ending at 
 last in the most minute twigs, each of which is distinctly 
 continuous with the central pith of the main stem, and 
 fulfils its individual share in causing the diversity of fig- 
 ure in the wood. 
 
 The knots are commonly harder than the general substance, and that more particularly in the softer 
 woods ; the knots of the deals, for example, begin near the axis of the tree, and at first show the min- 
 gling of the general fibres with those of the knot, much the same as in the origin of the branch of the 
 yew, in Fig. 3^)34 ; but after a little ■while it appears as if the branch, from elongating so much more 
 rapidly than the deposition of the annual rings upon the main stem, soon shot through and became 
 entirely detached, and the future rings of the trunk were bent and turned slightly aside when they 
 encountered the knot, but without uniting with it in any respeGt. 
 
 This may explain why the smooth cylindrical knots of the outer boards of white deal, pine, efec., so 
 frequently drop out when exposed on both sides in thin boards; whereas the turpentine in the red and 
 yellow deals may serve the part of a cement, and retain these kinds the more firmly. 
 
 The elliptical form of the knots in the plank is mostly due to the oblique direction in which they are 
 cut, and their hardness (equal to that of many of the tropical hard woods) to the close grouping of the 
 annual rings and fibres of which they are themselves composed. These are compressed by the sur- 
 rounding wood of the parent stem, at the time of the deposition ; whereas the principal layers of the 
 stem of the tree are opposed alone by the loosened and yielding bark, and only obtain the ordinary 
 density. 
 
 The knots of large trees are sometimes of considerable size. The writer has portions of one of those 
 of the Norfolk Island pine, ( Araucaria excelsa,) which attained the enormous size of about four feet 
 long, and four to six inches diameter. In substance it is throughout compact and solid, of a semi-trans- 
 parent hazel-brown, and it may be cut almost as well as ivory, and with the same tools, either into 
 screws, or with eccentric or drilled work, &c . ; it is an exceedingly appropriate material for ornamental 
 turning. 
 
 It is by some supposed, that the root of a tree is divided into about as many parts or subdivisions as 
 there are branches, and that, speaking generally, the roots spread around the trunk under ground to 
 about the same distance as the branches wave above ; the little germs or knots from which they proceed 
 being in the one case distributed throughout the length of the stem of the tree, and in the other crowded 
 together in the shorter portion buried in the earth. 
 
 If this be true, we have a sufficient reason for the beautiful but gnarled character of the roots of trees 
 when they are cut up for the aits ; many a block of the root of the walnut-tree, thus made up of small 
 knots and curls, and that was first intended for the stock of a fowling-piece, has been cut into veneers 
 and arranged in angular pieces to form the circular picture of a table ; and few pictures of this natural 
 kind will be found more beautiful. The roots of many trees also display very pretty markings ; some 
 are cut into veneers, and those of the olive-tree, and others, are much used on the continent for making 
 snuff-boxes. 
 
 The tops of the pollard-trees, such as the red oak, elm, ash, and other trees, owe their beauty to a 
 similar crowding together of the little germs, whence have originated the numerous shoots which pro- 
 ceeded from them after they have been lopped. The burrs or excrescences of the yew, and some other 
 trees, appear to arise from a similar cause, apparently the unsuccessful attempts at the formation of 
 branches from one individual spot ; from this may arise those bosses or wens, which almost appear as 
 the result of disease, and exhibit internally crowds of knots, with fibres surrounding them in the most 
 fantastic shapes. Sometimes the burrs occur of immense size, so as to yield a large and thick slab of 
 highly ornamental wood of most confused and irregular growth : such pieces are highly prized, and are 
 cut into thin veneers to be used in cabinet-w'ork. 
 
 It appears extremely clear likewise that the beautiful East Indian wood, called both Kiabooca and 
 
D24 
 
 WOODS, VARIETIES OF. 
 
 Amboyna, is, in like manner, the excrescence of a large timber-tree. Its character is very similar to (hi 
 burr of the yew-tree, but its knots are commonly smaller, closer, and the grain or fibre is more silky. 
 The Kiabooca has also been supposed to be cut from around the base of the cocoanut palm, a surmise 
 that is hardly to be maintained, although the latter may resemble it, as the Kiabooca is imported alone 
 from the East Indies, whereas the cocoanut palm is common and abundant both in the eastern and 
 western hemispheres. (See Kiabooca in the Catalogue.*) 
 
 The bird’s-eye maple shows, in the finished work, the peculiar appearance of small dots or ridges, 01 
 of little conical projections with a small hollow in the centre, (to compare the trivial with the grand 
 like the summits of mountains, or the craters of volcanoes,) but without any resemblance to knots, which 
 are the apparent cause of ornament in woods of somewhat similar character, as the burrs of the yew 
 and kiabooca, and the Russian maple, (or birch-tree :) this led us to seek a different cause for its 
 formation. 
 
 On examination, we found the stem of the American bird’s-eye maple, stripped of its bark, presented 
 little pits or hollows of irregular form, some as if made with a conical punch, others ill-defined and 
 flattened like the impression of a hob-nail ; suspecting these indentations to arise from internal spines 
 or points in the bark, a piece of the latter was stripped off from another block, when the surmise was 
 verified by their appearance. The layers of the wood being moulded upon these spines, each of their 
 fibres is abruptly curved at the respective places, and when cut through by the plane, they give, in the 
 tangential slice, the appearance of projections, the same as in some rose-engine patterns, and the more 
 recent medallic glyptographic or stereographic engravings, in which the closer approximation of the 
 lines, at their curvatures, causes those parts to be more black, (or shaded,) and produces upon the plane 
 surfaces the appearances of waves and ridges, or of the subject of the medaL 
 
 The short hues observed throughout the maple-wood, between the dots or eyes, are the edges of the 
 medullary rays; and the same piece of wood, when examined upon the radial section, exhibits the ordinary 
 silver grain, such as we find in the sycamore, (to which family the maple-tree belongs,) with a very few 
 of the dots, and those displayed in a far less ornamental manner. 
 
 The piece examined measured eight inches wide, and five and a half inches radially, and was appa- 
 rently the produce of a tree of about sixteen inches diameter ; the effect of the internal spines of the 
 bark was observable entirely across the same, that is, through each of the 130 zones of which it con- 
 sisted. The curvature of the fibres was in general rather greater towards the centre, which is to be 
 accounted for by the successive annual depositions upon the bark, detracting in a small degree from the 
 height or magnitude of the spines within the same, upon which the several deposits of wood were formed. 
 Other woods also exhibit spines, which may be iutended for the better attachment of the bark to the 
 stem, but, from their comparative minuteness, they produce no such effect on the wood as that which 
 exists, we believe exclusively, in the bird’s-eye maple. 
 
 This led me to conclude that in woods, the figures of which resemble the undulations, or the ripple- 
 marks on the sands, that frequently occur in satin-wood and sycamore, less frequently in boxwood, and 
 also in mahogany, ash, elm, and other woods, to be due to a cause explained by Fig. 3936, namely, a 
 serpentine or guilloche form in the grain : and on inspection, the fibres of all such pieces will be found 
 to be wavy, on the face, at right angles to that on which the ripple is observed, if not on both faces. 
 Those parts of the wood which happen to receive the light appear the brightest, and form the ascending 
 sides of the ripple, just as some of the medallic engravings appear in cameo or in intaglio, according t« 
 the direction in which the fight falls upon them. 
 
 :«36. 
 
 The woods possessing this wavy character generally split with an undulating fracture, the ridges 
 being commonly at right angles to the axis of the tree, or square across the board ; but in a specimen 
 of an Indian red wood, the native name of which is 6 'aliatour, the ridges are inclined at a considerable 
 angle, presenting a very peculiar appearance, seen as usual on the polished surface. 
 
 In those woods which possess in abundance the septa or silver grain, described by the botanist as the 
 medullary plates or rays, the representations of which, as regards the beech-tree, are given in Fig. 3930, 
 another source of ornament exists ; namely, a peculiar damask or dappled effect, somewhat analo- 
 gous to that artificially produced on damasked linens, moreens, silks, and other fabrics, the patterns 
 on which result from certain masses of the threads on the face of the cloth running lengthways, and 
 other groups crossways. Tins effect is observable in a remarkable degree in the more central planks of 
 oak, especially the light-colored wood from Norway, and'the neighborhood of the Rhine, called wainscot 
 and Dutch oak, (fee., and also in many other woods, although in a less degree. 
 
 In the oak plank, the principal streaks or fines are the edges of the annual rings, which show, as usual 
 
 * Mr. G. Loddiges considers the burrs may occur upon almost all old trees, and that they result “rom the last attempt at 
 the plant to maintain life, by the reparation of any injury it may have received. 
 
WOODS, VARIETIES OF. 
 
 925 
 
 parallel lines more or less waved from the curvature of the tree, or the neighboring knots and branches 
 and the damask pencillings, or broad curly veins and stripes, are caused by groups of the medullary 
 rays or septa , which undulate in layers from the margin to the centre of the tree, and creep in betwixt 
 the longitudinal fibres, above some of them and below others. The plane of the joiner, here and there, 
 intersects portions of these groups, exactly on a level with their general surface, whereas their recent 
 companions are partly removed in shavings, and the remainder dip beneath the edges of the annual 
 rings, which break their continuity ; this will be seen when the sepiia are purposely cut through by the 
 joiner’s plane. 
 
 Upon inspecting the ends of the most handsome and showy pieces of wainscot oak and similar woods, 
 it will be found that the surface of the board is only at a small angle with the lines of the medullary 
 rays, so that many of the latter “crop out” upon the surface of the work: the medullary plates being 
 seldom flat, their edges assume all kinds of curvatures and elongations from their oblique intersections. 
 All these peculiarities of the grain have to be taken into account in cutting up woods, when the most 
 showy character is a matter of consideration. 
 
 The same circumstances occur in a less degree in all the woods containing the silver grain, as the 
 oriental plane-tree, or lacewood, sycamore, beech, and many others, but the figures become gradually 
 smaller, until at last, in some of the foreign hard woods, they are only distinguishable on close inspec- 
 tion under the magnifier. Some of the foreign hard woods show lines very nearly parallel, and at right 
 angles to the axis of the tree, as if they were chatters or utters arising from the vibration of the plane- 
 iron. The medullary rays cause much of the beauty in all the showy woods, notwithstanding that the 
 rays may be less defined than in the woods cited.* 
 
 Jn many of the handsomely figured woods, some of the effects attributed to color would, as in dam- 
 ask, be more properly called those of light and shade, as they vary with the point of view selected 
 for the moment. The end grain of mahogany, the surfaces of the table-cloth, and of the mother-of-pearl 
 shell, are respectively of nearly uniform color, but the figures of the wood and the damask arise from 
 the various ways in which they reflect the light. 
 
 Had the fibres of all these substances been arranged with the uniformity and exactitude of a piece 
 of plain cloth, they would have shown an even uninterrupted color, but fortunately for the beautiful 
 and picturesque, such is not the case ; most fibres are arranged by nature in irregular curved lines, and 
 therefore almost every intersection through them, by the hand of man, partially removes some and 
 exposes others, with boundless variety of figure. 
 
 If further proof were wanted, that it is only the irregular arrangement that causes the damask or 
 variegated effect, we might observe that the plain and uniform silk, when passed in two thicknesses face 
 to face, between smooth rollers, comes out with the watered pattern ; the respective fibres mutually 
 emboss each other, and with the loss of their former regular character they cease to reflect the uniform 
 tintf 
 
 To so boundless an extent do the interferences of tints, fibres, curls, knots, &c., exist, that the cab- 
 inet-maker scarcely seeks to match any pieces of ornamental wood for the object he may be constructing. 
 He covers the nest of drawers, or tliQ table, with the neighboring veneers from the same block, the 
 proximity of the sections causing but a gradual and unobserved difference in the respective portions : 
 as it would be in vain to attempt to find two different pieces of handsomely figured wood exactly alike. 
 
 Variations of color . — The figures of the woods depend also upon the color as well as on the fibre ; 
 in some the tint is nearly uniform, but others partake of several shades of the same hue, or of tw r o or 
 three different colors, when a still greater change in their appearance results. 
 
 In the horizontal sections of such woods, the stripes wind partly round the centre, as if the tree 
 had clothed itself at different parts with coats of varied colors with something like caprice : tulip-wood, 
 kingwood, zebra-wood, rosewood, and many others, show this very distinctly ; and in the ordinary plank 
 these markiugs get drawn out into stripes, bands, and patches, and show mottled, dappled, or wavy figures 
 of the most beautiful or grotesque characters, upon which it would be needless to enlarge, as a glance 
 at the display of the upholsterer will convey more information than any description, even when assisted 
 by colored figures.:): 
 
 Those w r oods which are variegated both in grain and color, such as Amboyna, kingwood, some 
 mahogany, maple, partridge, rosewood, satin-wood, snakewood, tulip-wood, zebra-wood, and others, 
 are more generally employed for objects with smooth surfaces, such as cabinet-work, vases, and turned 
 ornaments, as the beauties of their colors and figures are thereby the best displayed. Every little detail 
 in the object causes a diversion in the forms of the stripes and marks existing in the wood : these ter- 
 minate abruptly round the mouldings which have sharp edges, and upon the flowing lines they are 
 undulated with infinite variety into curves of all kinds, which often terminate in fringes from the acci- 
 dental intersections of the stripes in the woods. 
 
 The elegant works in marquetry, in which the effect of flowers, ornamental devices, or pictures, is 
 attempted by the combination of pieces of naturally colored woods, are invariably applied to smooth 
 
 * The Cuticaem liranco, from Carvalho da Terra, Brazils, and Cuticaem vcrmo , brought over by Mr. Morney, (Admiralty 
 Museum,) show the silver grain very prettily ; the first in peculiar straight radial stripes, the other in small close patches. 
 The llcioa-rewa , ( Knightia cxcelsa,) from New Zealand, is of similar kind; all would be found handsome light-colored 
 furniture woods. 
 
 t The brilliant prismatic colors of the pearl are attributed to the decomposition and reflection of the light by the 
 numerous minute grooves or stria:, a more vivid effect of the same general kind. 
 
 A beautiful artificial example of the same description was produced by Sir John Barton, comptroller of the English 
 mint; he engraved with the diamond the surfaces of hard steel dies in lines as fine as 2000 in the inch, arranged in hex- 
 agons, &c. The gold buttons struck from these dies display the brilliant play of iridescent colors of the originals. 
 
 X Attempls have been made to stain some European woods during their growth, by inserting certain portions of their 
 roots in vessels tilled with coloring matters, but we are not aware with what success. It is not, however, to be expected 
 .hat such a mode would be either so effective or permanent as that produced by the natural absorption during the entire 
 period of the life of the plant, an experiment of too lengthened and speculative a character to be readily undertaken. 
 
926 
 
 WOODS, VARIETIES OF. 
 
 surfaces. In the same manner the beautifully tesselated wood floors, abundant in the buildings of one 
 or two centuries back, which exhibit geometrical combinations of the various ornamental woods, (an art 
 that has been recently pursued in miniature by the Tunbridge turners in tbeir Mosaic works,) are other 
 instances, that in such cases the plain smooth surface is the most appropriate to display the effect and 
 variety of the colors, for such of the last works as are turned into mouldings fail to give us the same 
 pleasure. 
 
 Even-tinted woods are best suited to the work of the eccentric chuck, the revolving cutters, and 
 other instruments to be explained; in which works, the carving is the principal source of ornament: 
 the variation of the wood, in grain or color, when it occurs, together with the cutting of the surface, is 
 rather a source of confusion than otherwise, and prevents the effect either of the material, or of the 
 work executed upon it, from being thoroughly appreciated. 
 
 The transverse section, or end grain of the plain woods, is the most proper for eccentric turning, as 
 all the fibres are then under the same circumstances ; many of the woods will not admit of being worked 
 with such patterns, the plankway of the grain: and of all the woods the black Botany Bay wood, or 
 the Black African wood, by which name soever it may be called, is most certainly the best for eccen- 
 tric turning; next to it, and nearly its equal, is the cocoa-wood, (from the West Indies, not the cocoa- 
 nut palm ;) several others may also be used, but the choice should always fall on those which are of 
 uniform tint, and sufficiently hard and close to receive a polished surface from the tool , as such works 
 admit of no subsequent improvement. 
 
 Contrary to the rule that holds good with regard to most substances, the colors of the generality of 
 the woods become considerably darker by exposure to the light ; tulip-wood is, we believe, the only one 
 that fades. The tints are also rendered considerably darker from being covered with oil or lacker, and 
 although the latter checks their assuming the deepest hues, it does not entirely prevent the subsequent 
 change. The yellow color of the ordinary varnishes greatly interferes also with the tints of the light 
 woods, for which the whitest possible kinds should be selected.* When it is required to give to wood 
 that has been recently worked the appearance of that which has become dark from age, as in repair- 
 ing any accident in furniture, it is generally effected by washing it with lime-water; or, in extreme 
 cases, by laying on the lime as water-color, and allowing it to remain for a few minutes, hours, or days, 
 according to circumstances. In many cases the colors of the woods are heightened or modified, by 
 applying coloring matters either before, or with the varnish ; and in this manner handsome bircliwood 
 is sometimes converted into factitious mahogany, by a process of coloring rather than dyeing, that often 
 escapes detection. 
 
 The bog-oak is by some considered to assume its black color from the small portion of iron contained 
 in the bog or moss, combining with the gallic acid of the wood, and forming a natural stain, similar to 
 writing ink. Much of the oak timber of the Royal George, that was accidentally sunk at Spithead, in 
 1782, and which has been recently extricated by Colonel Pasley’s sub-marine explosions, is only 
 blackened on its outer surface, and the most so in the neighborhood of the pieces of iron ; the inside of 
 the thick pieces is, in general, of nearly its original color and soundness. Some specimens of camwood 
 have maintained their original beautiful red and orange colors, although the inscription says that they 
 were “ washed on shore at Kay Haven, in October, 1840, with part of the wreck of the Royal Tar, lost 
 near the Needles twenty years ago, when all the crew perished.” 
 
 The recent remarks on color apply equally to the works of statuary, carving, and modelling gener- 
 ally : the materials for which are either selected of one uniform color, or they are so painted. Then 
 only is the full effect of the artist’s skill apparent at tire first glance ; otherwise it frequently happens 
 either that the eye is offended by the interference of the accidental markings, or fails to appreciate the 
 general form or design, without a degree of investigation and effort that detracts from the gratification 
 which would be otherwise immediately experienced on looking at such carved works. 
 
 This leads me to advert to modes sometimes practised to produce the effect of carving ; thus, in the 
 Manuel du Tourneurf a minute description will be found of the mode of making embossed wooden 
 boxes, which are pressed into metallic moulds, engraved with any particular device. The wood is first 
 turned to the appropriate shape, and then forced by a powerful screw-press into the heated mould, 
 (which is made just hot enough to avoid materially discoloring the wood;) it is allowed to remain in 
 that situation until it is cold ; this method, however, only applies to subjects in small relief, and is 
 principally employed on knotty pieces of boxwood and olive-wood of irregular curly grain. 
 
 The following method may be used for bolder designs, more resembling ordinary carving : the fine 
 sawdust of any particular wood it is required to imitate, is mixed with glue or other cementitious mat- 
 ter, and squeezed into metallic moulds ; but in the latter case the peculiar characteristic of the wood, 
 namely, its fibrous structure, is entirely lost, and the eye only views the work as a piece of cement or 
 composition, which might be more efficiently produced from other materials, and afterwards colored. 
 
 Each of these processes partakes rather of the proceeding of the manufacturer than of the amateur ; 
 extensive preparations, such as very exact moulds consisting of several parts, a powerful press and 
 other apparatus, are required, and the results are so proverbially alike, from being “ formed in the 
 same mould,” that they lose the interest attached to original works, in the same manner that engravings 
 are less valued than the original paintings from which they are copied. 
 
 Another method of working in wood may be noticed, which is at any rate free from the objections 
 recently advanced : we will transcribe its brief description.^; 
 
 “ Raised figures on wood, such as are employed in picture-frames and other articles of ornamental 
 cabinet-work, are produced by means of carving, or by casting the pattern in Paris plaster or other 
 
 * Specimens of woods for cabinets should be left in their natural state, or at most they should be polished by friction 
 only ; or, if varnished, then upon the one side alone. Their colors are best preserved when they are excluded from tin 
 light, either in drawers or in glass cases covered with some thick blind, 
 t Second edition, vol. ii., pp. 441-451. J Transactions of the Society of Arts, xlii., p. B. 
 
WOODS, VARIETIES OF. 
 
 927 
 
 composition, and cementing or otherwise fixing it on the surface of the wood. The former mode is 
 expensive, the latter is inapplicable on many occasions. 
 
 The invention of Mr. Straker may be used either by itself or in aid of carving ; and depends on the 
 facts, that if a depression be made by a blunt instrument on the surface of wood, such dejrressed part 
 will again rise to its original level by subsequent immersion in water. 
 
 “ The wood to be ornamented having first been worked out to its proposed shape, is in a state to 
 receive the drawing of the pattern ; this being put in, a blunt steel tool, or burnisher, or die, is to be 
 applied successively to all those parts- of the pattern intended to be in relief, and at the same time is 
 to be driven very cautiously, without breaking the grain of the wood, till the depth of the depression 
 is equal to the subsequent prominence of the figures. The ground is then to be reduced by planing 
 or filing to the level of the depressed part ; after which, the piece of wood being placed in water, 
 either hot or cold, the parts previously depressed will rise to their former height, and will thus form an 
 embossed pattern, which may be finished by the usual operations of carving.'’ 
 
 Shrinking and warping . — The permanence of the form and dimensions of the woods require par- 
 ticular consideration, even more than their comparative degrees of ornament, especially as concerns 
 tnose works which consist of various parts, for unless they are combined with a due regard to the 
 strength of the pieces in different directions, and to the manner and degree in which they are likely to 
 be influenced by the atmosphere, the works will split or warp, and may probably be rendered entirely 
 useless. 
 
 The piece of dried wood is materially smaller than in its first or wet state, and as it is at all times 
 liable to re-absorb moisture from a damp atmosphere, and to give it off to a dry one, even after having 
 been thoroughly seasoned, the alterations of size again occur, although in a less degree. 
 
 The change in the direction of the length of the fibres is in general very inconsiderable.* It is so 
 little in those of straight grain, that a rod split out of clean fir or deal is sometimes employed as the 
 pendulum of a clock, for which use it is only inferior to some of the compensating pendulums : whereas 
 a piece of the same wood taken diametrically out of the centre of a tree, or the crossway of the grain, 
 forms an excellent hygrometer, and indicates by its change of length the comparative degree of moist- 
 ure of the atmosphere. The important difference in the general circumstances of the woods, in the 
 two directions of the grain, we propose to notice, first as regards the purposes of turning, and afterwards 
 those of joinery work, which will render it necessary to revert to the wood in its original, or unseasoned 
 state. 
 
 The turner commonly employs the transverse section of the wood, and we may suppose the annual 
 rings then exhibited to consist of circular rows of fibres of uniform size, each of which, for -the sake of 
 explanation, I will suppose to be the one-hundredth of an inch in diameter. 
 
 When the log of green wood is exposed to a dry atmosphere, the outer fibres contract both at the 
 sides and ends, whereas those within are in a measure shielded from the immediate effect of the atmos- 
 phere, and nearly retain their original dimensions. Supposing all the outside fibres to be reduced to 
 the one hundred and tenth, or the one hundred and twentieth of an inch, as the external series can no 
 longer fill out the original extent of the annual ring, the same as they did before they were dried ; they 
 divide, not singly, but into groups, as the unyielding centre, or the incompressible mass within the arch, 
 causes the parts of which the latter is composed to separate, and the divisions occur in preference at 
 the natural indentations of the margin, which appear to indicate the places where the splits are likely 
 to commence. 
 
 The ends being the most exposed to the air, are the 
 first attacked, and there the splits are principally 
 radial, with occasional diversions concentric with the 
 layers of fibres, as in Fig. 3937, and on the side of the 
 log the splits become gradually extended in the direc- 
 tion of its length. The air penetrates the cracks, and 
 extends both cause and effect, and an exposure of a 
 few weeks, days, or even one day, to a hot, dry atmos- 
 phere, will sometimes spoil the entire log, and the 
 more rapidly the harder the wood, from its smaller 
 penetrability to the air. This effect is in part stayed 
 by covering the ends of the wood with grease, wax, 
 glue, or paper, to defend them, but the best plan is to 
 transfer the pieces very gradually from the one atmos- 
 phere to the other, to expose them equally to the air 
 at all parts, and to avoid the' influence of the sun and 
 hot, dry air. 
 
 The horizontal slice or block of the entire tree is the 
 most proper for the works of the lathe, as it is presented by nature the most nearly prepared to oui 
 hand, and its appearance, strength, grain, and shrinking, are the most uniform. The annual rings, if any 
 be visible, are, as in Fig. 3938, nearly concentric with the object, the fibres around the circumference are 
 
 393 /. 
 
 * Good boxwood and lancewood were approved as materials for the verified scales to be employed in laying down the 
 plans for the recent parliamentary survey, as being next in accuracy to those of metal ; whereas scales of ivory are entirely 
 rejected by them, owing to their material variation in length under hygrometrical influence. See their printed papers. 
 
 Mr. Fincham says he has found a remarkable variation in the New Zealand pine, the Kowrie or Cowrie, corrupted into 
 Cowdie, which expands so much as to cause the strips constituting the inside mouldings of ships to expand and buckle, 
 probably from the comparative moisture of our atmosphere; and Colonel Lloyd says he found the teak timbers used by 
 nim in constructing a large room in the Mauritius, to have shrunk three-quarters of an inch in lentr'h in thirty-eigh* leei, 
 although this wood is by many considered to shrink sideways least of all others. 
 
928 
 
 WOODS, VARIETIES OF. 
 
 alike, and the contraction occurs without causing any sensible departure from the circular form. Al- 
 though thin transverse slices are necessarily weak from the inconsiderable length of the fibres of which 
 they are composed, (equal only in length to the thickness of the plate,) they are strengthened in the 
 generality of turned works by the margin, such as we find in the rim of a snulf-box, which supports the 
 bottom like the hoop of a drum or tamborine. 
 
 The entire circular section is therefore most appropriate for turning ; next to it the quartering, Fig. 
 3939, should be chosen, but its appearance is less favorable ; and a worse effect happens, as the shrink- 
 ing causes a sensible departure from the circle, the contraction being invariably greater upon the circu- 
 lar arcs of fibres, than the radial lines or medullary rays. If such works be turned before the materials 
 
 3938 . 3939 . 3940 . 
 
 are thoroughly prepared, they will become considerably oval ; so much so, that a manufacturer who is 
 in the habit of working up large quantities of pear-tree, informs me that hollowed pieces rough-turned 
 to the circle, alter so much and so unequally in the drying, that works of three inches will sometimes 
 shrink half an inch more on the one diameter than the other, and become quite oval ; it is therefore 
 necessary to leave them half an inch larger than the intended size. Even in woods that were com- 
 paratively dry, a small difference may in general be detected by the callipers, when they have been 
 turned some time, from their unequal contraction. 
 
 In pieces cut lengthways, such as Fig. 3940, circumstances are still less favorable ; there being no 
 perceptible contraction in the length of the fibres, the whole of the shrinking takes place laterally, at 
 right angles to them, and the w T ork becomes oval to the full extent of the contraction that occurs in the 
 fibres. 
 
 The plank-wood is almost solely employed for large disks which would be too weak if cut out trans- 
 versely ; and in some cases for objects made of those ornamental woods which are best displayed in 
 that section, as the tulip, rose, king, zebra, partridge, and satin woods. Specimens of oak from ancient 
 buildings are sometimes thus worked, but in all such cases the wood should be exceedingly well dried 
 beforehand ; otherwise, in addition to the inconvenience arising from the greater departure from the 
 circle, the pieces will warp and twist, an effect that more generally concerns the joiner’s art, and to the 
 consideration of which we will now proceed. 
 
 When the green wood is cut up into planks, boards, and veneers, the splitting which occurs in the 
 transverse section is less to be feared than distortion or warping, from the unequal contraction of the 
 fibres. Thick planks are partially stayed from splitting and opening, by cleets nailed upon each end ; 
 boards are left unprotected, and veneers are protected from accidental violence by slips of cloth glued 
 upon each end. 
 
 One plank only in each tree can be exactly diametrical, the others are parallel therewith, and, as 
 shown in Fig. 3937, the two sides of all the boards, but that from the centre are differently circum- 
 stanced as regards the arrangement of the fibres, and contract differently. It will be generally found 
 that the boards exposed to similar conditions on both sides, become, from the simple effect of drying, 
 convex on the side towards the centre of the tree ; this will be explained by a reference to the diagram. 
 
 3941 . 
 
 Fig. 3941, which shows that the longest continuous line of fibres is concentric with the axis of the tree. 
 Thus let a, h, c, d, e,f represent the section of a board, the line b e of which is supposed to contain five 
 fibres, and the arc d bf thirty : therefore, supposing every fibre to shrink alike in general dimensions, 
 the contraction on the arc will be six times that upon the short radial line, and the new margin of the 
 board will be the dotted line which proceeds from g to h, the departure of which from the original 
 straight line will be five times as much at d as at e. 
 
 3942 . 
 
 1 2 3 4 5 6 
 
 This is not imaginary, as it is in all cases borne out by observation, where the pieces are exposed to 
 similar circumstances on both sides. When a true flat board is wanted, it is a common practice to saw 
 
WOODS, VARIETIES OF. 
 
 02!) 
 
 the wide plank in two or four pieces, to change sides with them alternately, and glue them together 
 again, as in Fig. 3942, so that the pieces 1, 3, 5 may present the sides towards the axis of the tree, and 
 2,4, 6 those towards its circumference ; the curvature from shrinking will then become a serpentine line 
 consisting of six arcs, instead of one continuous circular sweep. 
 
 When the opposite sides of a board are exposed to unequal conditions, the moisture will swell the 
 fibres on the one side and make that convex, and in the opposite manner that exposed to the dry air 
 or heat will contract and become concave ; from these circumstances', when several pieces of wood are 
 placed around the room or before the fire, “ to air’' the sides should be continually changed, that both 
 may have equal treatment, so as to lessen the tendency to curvature. To remedy the defect when it 
 may have occurred, the joiner exposes the convex side to the fire, but it is obviously better to be spar - 
 ing of these sudden changes. 
 
 Any unequal treatment of the two sides is almost sure to curl the board ; if, for instance, we paste 
 a sheet of paper upon one side of a board, it will in the first instance swell the surface and make it 
 convex ; as the paper dries it contracts, it forces the wood to accompany it, and the papered side be- 
 comes hollow ; when two equal papers are pasted on opposite sides, this change does not generally 
 occur. A similar effect is often observed when a veneer is glued on a piece of wood ; hence it is usual 
 to swell the surface on which the veneer is to be laid, by wetting it with a sponge dipped in thin size, 
 so as to make it moderately round ; in this case, the wetted surface of the board, and the glued surface 
 of the veneer, are expanded nearly alike by the moisture, and in drying they also contract alike, so that 
 under favorable management the board recovers its true flat figure. 
 
 The woods are much less disposed to become curved in the direction of their length, than crossways ; 
 but another evil equally or more untractable is now met with, as the general figure of the board is more 
 or less disposed to twist and warp, so that when it is laid upon a flat surface it touches only at the two 
 diagonal corners, and is said to be “ in winding.” This error is the less experienced in the straight- 
 grained pines and mahogany, which are therefore selected for works in which constancy of figure is a 
 matter of primary importance, as in models for the foundry, and objects exposed to great vicissitudes 
 of climate. 
 
 The warping may arise from the curved direction of the fibres in respect to the length of the plank, 
 and also from the spiral direction in which many trees grow ; in some, for example, the furrows of the 
 bark are frequently twisted as much as fifteen or twenty degrees from the perpendicular, and some- 
 times even thirty and forty. The woods themselves when split through the centre of the tree differ 
 materially ; they sometimes present a tolerably flat surface, at others they are much in winding or 
 twisted, a further corroboration of the “spiral growth;” we cannot be therefore much surprised that 
 the planks cut out from such woods should in a degree pursue the paths thus early impressed upon 
 them. 
 
 Boxwood is often very much twisted in this manner. The writer had a block, the diameter of which 
 was nine inches ; its surface was split at five parts, with spiral grooves, at an angle of nearly thirty 
 degrees with the axis ; these made exactly one complete revolution, or one turn of a screw in the length 
 of the piece, which was just three feet. 
 
 On the other hand, the Alerce, a pine growing in the island of Chiloe in South America, to the diam- 
 eter of about four feet, and whose wood resembles the cedar of Lebanon in color, is so remarkably 
 straight in the grain, that it is the custom of the country to split it into planks about eight feet long and 
 seven inches wide, which are almost as true as if they were cut witli the saw, although of course not 
 cpiite so smooth. 
 
 To correct the errors of winding and curvature in length, the joiner, :'n working upon rigid pieces, first 
 planes off the higher points so as to produce the true form by reduction. But when the objects are 
 long and thin, they are corrected by the hands, just as we should straighten a cane, or a walking stick, 
 except that the one angle of the board is rested upon the bench or floor, the other is held in the hand, 
 and the pressure is applied between them. 
 
 Broad thin pieces are sometimes warmed on both sides before the 
 fire to lessen their rigidity ; they are then fixed between two stout 
 flat boards by means of several hand-screws, and allowed to remain 
 until they are quite cold ; this is just the reverse of the mode of bend- 
 ing timber for ship-building and other purposes, but applied in a less 
 elaborate manner. 
 
 In concluding this division of the subject, we may observe that the 
 shrinking and contracting of the straight-grained woods, especially 
 deal and mahogany, cause but little distortion of their general shape 
 after they have been properly dried ; but the diversity of grain, a 
 principal cause of beauty of figure in the ornamental woods, is at the 
 same time a source of confusion in their shrinking, which being called 
 on to pursue many paths, (which are parallel with the fibres, however 
 tortuous,) gives rise to a greater disturbance from the original shape, 
 or in extreme cases, even causes them to split where the contraction 
 is restrained by the peculiarity of growth. 
 
 In the handsome furniture woods the economy of manufacture cor- 
 rects this evil, as from their great value they are cut into very thin 
 slices or veneers, and glued upon a stout fabric of straight-grained 
 wood, commonly inferior mahogany, cedar, or deal, by which the op- 
 posite characters, of beauty of appearance and permanence of form, are combined at a moderate ex- 
 pense ; these processes will be explained. 
 
 Combining different pieces of wood. — In combining several pieces of wood for works in carpentry 
 and cabinet-makiug, the different circumstances of the plank as respects its length and width should 
 Yon. II. — 59 
 
 3943. 
 
930 
 
 WOODS, VARIETIES OF. 
 
 l>e always borne in mind. Provision must be made that the shrinking and swelling are as little re- 
 strained as possible, otherwise the pieces may split and warp with an irresistible force : and the prin- 
 cipal reliance for permanence or standing, should be placed on those pieces, (or lines of the work,) cut 
 out the lengthway of the plank, which are, as before explained, much less disposed to break or become 
 crooked, than the crossway sections : these particulars will be more distinctly shown by one or twe 
 illustrations. 
 
 Let abed represent the flat surface of a board ; e f, the edge of the same, and g li the end ; no con- 
 traction will occur upon the line e f or the length, and in the general way, that line will remain 
 pretty straight and rigid; but the whole of the shrinking will take place on gh, the width, which is 
 slender, flexible, and disposed to become curved from any unequal exposure to the air; the four 
 marginal lines of abed, are not likely to alter materially in respect to each other, but they will 
 remain tolerably parallel and square, if originally so formed. 
 
 A dovetailed box consists of six such pieces, the four sides of which, ABCD, Fig. 3944, are inter- 
 laced at the angles by the dovetails, so that the flexible lines, as g h, on B, are connected with, and 
 strengthened by, the strong lines, as c d, on A, and so on : the whole collectively form a very rigid 
 frame, the more especially when the bottom piece is fixed to the sides by glue or screws, as it entirely 
 removes from them the small power of racking upon the four angles, (by a motion like that of the 
 jointed parallel rule,) which might happen if the dovetails, shown on a larger scale in Fig. 3945, were 
 loosely fitted. 
 
 3945. 3944. 
 
 When the grain of the four sides ABCD runs in the same direction, or parallel with the edges Of 
 the box or drawer, as shown by the shade lines on A and B, and the pieces are equally wet or dry, 
 hey will contract or expand equally, and without any mischief or derangement happening to the work ; 
 to insure this condition, the four sides are usually cut out of the same plank. But if the pieces had the 
 grain in different directions, as C and D, and the tw r o were nailed together, D would entirely prevent 
 the contraction or expansion of C, and the latter would probably be split or cast, from being restrained. 
 When admissible, it is therefore usual to avoid fixing together those pieces, in which the grain runs 
 respectively lengthways and crossways, especially where apprehension exists of the occurrence of 
 swelling or shrinking. 
 
 A wide board, Fig. 8945-J-, composed of the slips ABODE, (reversed as in Fig. 3942,) is rendered 
 still more permanent, and very much stronger, when its ends are confined by two clamps, such as G H, 
 (one only seen ;) the shade lines represent the direction of the grain. The group of pieces, A to E, con- 
 tract in width upon the line A E, and upon it they are also flexible, whereas the clamp G H is strong 
 and incapable of contraction in that direction, and therefore unless the wood is thoroughly dry the two 
 parts should be connected in a manner that will allow for the alteration of the one alone. This is 
 effected by the tongue and groove fitting as represented ; the end piece G H is sometimes only fastened 
 by a little glue in the centre of its length, but in cabinet-work, where the seasoning of the wood is gen- 
 erally better attended to, it is glued throughout. 
 
 If the clamp GII were fixed by tenons, (one of which, ij, is shown detached in Fig. 3946,) the con 
 fraction of the part of the board between the tenons might cause it to split, the distance between the 
 
WOODS, VARIETIES OF. 
 
 931 
 
 mortises in G H being unalterable ; or the swelling of the board might cause it to bulge, and become 
 rounding ; or the entire frame would twist and warp, as the expansion of the centre might be more 
 powerful than the resistance to change in the two clamps, and force them to bend. 
 
 It is therefore obvious that if any question exist as to the entire and complete dryness of the wood, 
 the use of clamps is hazardous; although in their absence, the shrinking might tear away the wood 
 from the plain glue-joint, even if it extended entirely across, without causing any further mischief, but 
 more generally the shrinking would split the solid board. 
 
 Another mode of clamping is represented at K ; it is there placed edgeways, and attached by an 
 undercut or dovetailed groove, slightly taper in its length, and is fixed by a little glue at the larger 
 end, which holds the two in firm contact : each of these modes, and some others, are frequently em- 
 ployed for the large drawing-boards required by architects and engineers for the drawings made with 
 squares and instruments. 
 
 From a similar motive, the thin bottom of a drawer is grooved into the two sides and front, and only 
 fixed to the back of the drawer by a few small screws or brads, so that it may swell or shrink without 
 splitting, which might result were it confined all around its margin. It is more usual, however, to glue 
 thin slips along the sides of large drawers, as in Fig. 3947, which strengthen the sides, and being grooved 
 to receive the bottom, allow it to shrink without interfering either with the front or back of the drawer. 
 
 In an ordinary door with two or more panels, all the marginal pieces ruu lengthways of the grain ; 
 the two sides, called the stiles, extend the whole height, and receive the transverse pieces or rails, now 
 mortised through the stiles, and wedged tight, but without risk of splitting, on account of their small 
 width ; every panel is fitted into a groove within four edges of the frame. The width of the panel 
 should be a trifle less than the extreme width of the grooves, and even the mouldings, when they are 
 not worked in the solid, are fixed to the frame alone, and not to the panel, that they may not interfere 
 with its alterations ; therefore in every direction, we have the framework in its strongest and most 
 permanent position as to grain, and the panel is unrestrained from alteration in width if so disposed. 
 
 This system of combination is carried to a great extent in the tops of mahogany billiard-tables, which 
 consist of numerous panels about 8 inches square, the frames of which are 3-J- in. wide and 1-^- in. thick ; 
 the panels are ploughed and tongued, so as to be level on the upper side, and from their small size the 
 individual contraction of the separate pieces is insignificant, and consequently the general figure of the 
 table is comparatively certain. Of late years, we are told that slate, a material uninfluenced by the 
 atmosphere, has been almost exclusively used ; the top of a full-sized table, of 1 2 by 6 feet, consists 
 of four slabs one inch thick, ground on their lower, and planed by machinery on their upper surfaces : 
 the iron tables are almost abandoned for several reasons. Large thin slates, from their permanence of 
 form, are sometimes used by engineers and others for drawing upon, and also in carpentry for the 
 panels of superior doors. 
 
 On glueing various works in wood. — Glue is the cement used for joining different pieces of wood ; 
 it is a common jelly, made from the scraps that are pared off the hides of animals before they are 
 subjected to the tan-pit for conversion into leather. The inferior kinds of glue are often contaminated 
 with a considerable portion of the lime used for removing the hair from the skins, but the better sorts 
 are transparent, especially the thin cakes of the Salisbury glue, which are of a clear amber color. 
 
 In preparing the glue for use, it is most usually broken into small pieces, and soaked for about 
 twelve hours in as much water as will cover it ; it is then melted in a glue-kettle, which is a double 
 vessel or water-bath, the inner one for the glue, the outer for the water, in order that the temperature 
 applied may never exceed that of boiling water. The glue is allowed at first to simmer gently for one 
 or two hours, and if needful it is thinned by the addition of hot water, until it runs from the brush in a 
 fine stream; it should be kept free from dust and dirt by a cover, in which a notch is made for the 
 brush. Sometimes the glue is covered with water, and boiled without being soaked. 
 
 Glue is considered to act in a twofold manner, first by simple adhesion, and secondly by excluding 
 the air, so as to bring into action the pressure of the atmosphere. The latter, however, alone is an 
 insufficient explanation, as the strength of a well-made glue-joint is frequently greater than the known 
 pressure of the atmosphere : indeed, it often exceeds the strength of the solid wood, as the fracture 
 does not at all times occur through the joint, and when it does, it almost invariably tears out some of 
 the fibres of the wood ; mahogany and deal are considered to hold the glue better than any other 
 woods. 
 
 It is a great mistake to depend upon the quantity or thickness of the glue, as that joint holds the 
 best in which the neighboring pieces of wood are brought the most closely into contact ; they, should 
 first be well wetted with the glue, and then pressed together in various ways to exclude as much of it 
 as possible, as will be explained. 
 
 The works in turnery do not in general require much recourse to glue, as the parts are more usually 
 connected by screws cut upon the edges of the materials themselves ; but when glue is used by the 
 turner, the mode of proceeding is so completely similar to that practised in joinery-works, that no 
 separate instructions appear to be called for, especially as those parts in which glue is required, as for 
 example in Tunbridge ware, partake somewhat of the nature of joinery-work. 
 
 When glue is applied to the end grain of the wood, it is rapidly absorbed in the pores ; it is therefore 
 usual first to glue the end wood rather plentifully, and to allow it to soak in to fill the grain, and then 
 to repeat the process until the usual quantity will remain upon the face of the work ; but it never 
 holds so well upon the endway as the lengthway of the fibres. 
 
 In glueing the edges of two boards together they are first planed very straight, true, and square ; 
 they are then carefully examined as to accuracy, and marked, to show which way they are intended 
 to be placed. The one piece is fixed upright in the chaps of the bench, the other is laid obliquely 
 against it, and the glue-brush is then run along the angle formed between their edges, which are then 
 placed in contact, and rubbed hard together lengthways, to force out as much of the glue as possible. 
 When the joint begins to feel stiff under the hand, the two parts are brought into their intended 
 
932 
 
 WOODS, VARIETIES OE. 
 
 position and left to dry ; or as the bench cannot in general be spared so long, the work is cautiously 
 removed from it, and rested in contact with a slip of wood placed against the wall, at a small incli- 
 nation from the perpendicular. Two men are required in glueing the joints of long boards. 
 
 In glueing a thin slip of wood on the edge of a board, as for a moulding, it is rubbed down very 
 close and firm, and if it show any disposition to spring up at the ends, it is retained by placing thereoa 
 heavy weights, which should remain until the work is cold ; but it is a better plan to glue on a wide 
 piece, and then to saw off the part exceeding that which is required. 
 
 Many works require screw-clamps and other contrivances, to retain the respective parts in contact 
 whilst the glue is drying ; in others, the fittings by which the pieces are attached together supply the 
 needful pressure. For instance, in glueing the dovetails of a box, or a drawer, such as Fig. 3944, dove- 
 tails, if properly fitted, hold the sides together in the requisite manner, and the following is the order 
 of proceeding. 
 
 The dovetail pins, on the end B, Fig. 3944, are first sparingly glued, that piece is then fixed in the 
 chaps of the bench, glue upwards, and the side A, held horizontally, is driven down upon B by blows 
 of a hammer, which are given upon a waste piece of wood, smooth upon its lower face, and placed 
 over the dovetail pins, which should a little exceed the thickness of the wood, so that when their 
 superfluous length is finally planed off, they may make a good clean joint. When the pins of the 
 dovetails come flush with the face, the driving-block is placed beside them to allow the pins to rise 
 above the surface. The second end, D, is then glued the same as B, it is also fixed in the bench, and 
 A is driven down upon it as before ; this unites the three sides of the square. The other pins on the 
 ends B and D are then glued, and the first side, A, is placed downwards on the bench, upon two slips 
 of wood placed close under the dovetails, that it may stand solid, and the remaining side, D, is driven 
 down upon them to complete the connection of the four sides. 
 
 The box is then measured with a square, to ascertain if it have accidentally become rhomboidal, or 
 out of square, which should be immediately corrected by pressure in the direction of the longer 
 diagonal ; lastly, the superfluous glue is scraped off whilst it is still soft with a chisel, and a sponge 
 dipped in the hot water of the glue-kettle is occasionally used, to remove the last portion of glue from 
 the work. 
 
 The general method pursued in glueing the angles of the frame for a panel is somewhat similar, 
 although modified, to meet the different structure of the joints. The tenons are made quite parallel 
 both ways, but the mortises are a little bevelled or made longer outside, to admit the small wedges by 
 which the tenons are fastened ; and the stiles are made somewhat longer than when finished, to pre- 
 vent the mortises from being broken out in driving the wedges, which are mostly cut out of the waste 
 pieces sawn off from the tenons in forming their shoulders or haunches. These details are seen in Fig. 3946. 
 
 In glueing the frame for a single panel which is fitted into a groove, the whole of the frame is put 
 together before commencing the glueing, and the stiles are knocked off one at a time, by which the 
 misplacement of the pieces is avoided. The tenons are glued, and a little glue is thrust into the two 
 mortises with a thin piece of wood; when the stiles have been driven down close, the joint is com- 
 pleted by the insertion of a wedge on each side of the tenon ; their points are dipped in the glue, and 
 they are driven in like nails, so as to fill out the mortises, after which the tenons cannot be with- 
 drawn : sometimes the wedges are driven into saw-kerfs, previously made near the sides of the tenons ; 
 the other stile is then knocked off, glued, and fixed in the same manner. Occasionally all four tenons 
 are glued at the same time, and the two stiles are pressed together by screw-clamps, stretching across 
 the frame just within the tenons; the wedges are lastly driven in, before the removal of the damps, 
 and the door, if square and true, is left to dry. 
 
 In many other cases also, the respective pieces are pressed together by screws variously contrived ; 
 the boards employed to save the work from being disfigured by the screws are planed flat, and are 
 warmed before the fire, to supply heat to keep the glue fluid until the work is screwed up, and the 
 warmth afterwards assists in drying the glue : such heated boards are named cauls, and they are par- 
 ticularly needed in laying down large veneers, which process is thus accomplished. 
 
 The surfaces of the table or panel, and both sides of the veneer, are scratched over with a tool callec 
 a toothing-plane, which has a perpendicular iron full of small grooves, so that it always retains a notchec 
 or serrated edge ; this makes the roughness on the respective pieces, called the tooth or key, for the hold 
 of the glue. A caul of the size of the table is made ready ; and several pairs of clamps, each consisting 
 of two strong wooden bars, placed edgeways, and planed a little convex or rounding on their inner 
 edges, and connected at their extremities with iron screw-bolts and nuts, are adjusted to the proper 
 opening ; the table is warmed on its face, and the veneer and caul are both made very hot* 
 
 All being ready, the table is brushed over quickly with thin glue or size, the veneer is glued and laid 
 on the table, then the hot caul, and lastly the clamping-bars, which are screwed down as quickly as 
 possible, at distances of three or four inches asunder, until they lie exactly flat. The slender veneer is 
 thereby made to touch the table at every point, and almost the -whole of the glue is squeezed out, as 
 the heat of the caul is readily communicated through the thin veneer to the glue and retains it in a 
 state of fluidity for the short space of time required for screwing down, when several active men are 
 engaged in the process. The table is kept under restraint until entirely cold, generally for the whole 
 night at least, and the drying is not considered complete under two or three days.f 
 
 * If the clamps were straight, their pressure would be only exerted at the sides of the table ; but being curved to the 
 extent of one inch in three or four feet, their pressure is first exerted in the centre, and gradually extends over their entire 
 length, when they are so far strained as to make the rounded edge bear flat upon the table and caul respectively. 
 
 + In some of the large manufactories for cabinet-work, the premises are heated by steam-pipes, in which case the} have 
 frequently a close stove in every workshop, heated many degrees beyond the general temperature, for giving the final 
 seasoning to the wood, for heating the cauls, and for warming the glue, which is then done by opening a small steam-pips 
 Into the outer vessel of the glue-pot. The arrangement is extremely clean, safe from fire, and the degree of the heat is 
 very much under control. 
 
WOODS, VARIETIES OF. 
 
 When the objects to be glued are curved, the cauls, or moulds, must be made of the counterpart 
 cm ve, so as to fit them ; for example, in glueing the sounding-board upon the body of a harp, which 
 may be compared to the half of a cone, a trough or caul is used of a corresponding curvature, and fur- 
 nished all along the edge with a series of screws to bring the work into the closest possible contact. 
 
 In glueing the veneers of maple, oak, and other woods upon curved mouldings, such as those for pic- 
 ture-frames, the cauls or counterpart moulds are made to fit the work exactly. The moulding is usu- 
 ally made in long pieces and polished, previously to being mitred or joined together to the sizes re- 
 quired. 
 
 In works that are curved in their length, as the circular fronts of drawers, and many of the foundry 
 patterns that are worked to a long sweep, the pieces that receive the pressure of the screws used in 
 fixing the work together “ whilst it is under glue,” are made in narrow slips, and pierced with a small 
 hole at each end; they are then strung together like a necklace, but with two strings. This flexible 
 caul can be used for all curves ; the strings prevent the derangement of the pieces whilst they are being 
 fixed, or their loss when they are not in use. 
 
 We have mentioned these cases to explain the general methods, and to urge the necessity of thin glue, 
 of a proper degree of warmth to prevent it from being chilled, and of a pressure that may cause the 
 greatest possible exclusion of glue from the joint. But for the comparatively small purposes of the 
 amatuer, four or six hand-screws, or ordinary clamps, or the screw-chaps of the bench, aided by a string 
 to bind around many of the curvilinear and other works, will generally suffice. 
 
 As, however, the amateur may occasionally require to glue down a piece of veneer, we will, in con- 
 clusion, describe the method of “ laying it with the hammer,” which requires none of the apparatus just 
 described, but the veneering hammer alone. This is either made of iron with a very wide and thin plane, 
 or more generally of a piece of wood from three to four inches square, with a round handle projecting 
 from the centre ; the ODe edge of the hammer-head is Sawn down for the insertion of a piece of sheet- 
 iron or steel, that projects about one-quarter of an inch, the edge of which is made very straight, smooth, 
 and round ; and the opposite side of the square wooden head of the veneering hammer is rounded, to 
 avoid its hurting the hand. 
 
 The table and both sides of the veneer having been toothed, the surface of the table is warmed, and 
 the outer face of the veneer and the surface of the table are wetted with very thin glue or with a stiff 
 size. The inner face of the veneer is next glued ; it is held for a few moments before a blazing fire of 
 shavings to render the glue very fluid, it is turned quickly down upon the table, and if large is rubbed 
 down by the outstretched hands of several men ; the principal part of the remainder of the glue is then 
 forced out by the veneering hammer, the edge of which is placed in the centre of the table ; the work- 
 man leans with his whole weight upon the hammer, by means of one hand, and with the other he wrig- 
 gles the tool by its handle, and draws it towards the edge of the table, continuing to bear heavily upon 
 it all the time. 
 
 The pressure being applied upon so narrow an edge, and which is gradually traversed or scraped 
 over the entire surface, squeezes out the glue before it, as in a wave, and forces it out at the edge ; hav- 
 ing proceeded along one line, the workman returns to the centre, and wriggles the tool along another 
 part close by the side of the former ; and in fact as many men are generally engaged upon the surface 
 of the table as the shop will supply, or that can cluster around it. The veneer is from time to time 
 wetted with the hot size, which keeps up the warmth of the glue, and relieves the friction of the ham- 
 mers, which might otherwise tear the face of the wood. 
 
 The wet and warmth also render the veneer more pliable, and prevent it from cracking and curling 
 up at the edges, as should the glue become chilled the veneer would break from the, sudden bending to 
 which it might be subjected, by the pressure of the hammer just behind the wave of glue, which latter 
 would be then too stiff to work out freely, owing to its gradual loss of fluidity ; the operation must, 
 therefore, be conducted with all possible expedition. 
 
 The concluding process is to tap the surface all over with the back of the hammer, and the dull hol- 
 low sound will immediately indicate where the contact is incomplete, and here the application of the 
 hammer must be repeated ; sometimes when the glue is too far set in these spots, the inner vessel of 
 the glue-pot or heated irons are laid on to restore the warmth. By some, the table is at the conclusion 
 laid flat on the floor, veneer downwards, and covered over with shavings, to prevent the too sudden ac- 
 cess of air. Of course, the difficulty of the process increases with the magnitude of the work ; the mode 
 is more laborious and less certain than that previously described, although it is constantly resorted to 
 for the smaller pieces and strips of veneer. 
 
 CHARACTERS AND USES OF THE WOODS COMMONLY EMPLOYED IN MECHANICAL AND 
 
 ORNAMENTAL ARTS. 
 
 Abele. See Poplar. 
 
 Acacia, true. The Acacia proximo, Mordi, A. Guillard’s MSS., called in Cuba Sabicii, and in England 
 Savico and Savacu, is a heavy, durable wood of the red-mahogany character, but rather darker and 
 plainer ; it is highly esteemed in ship-building. 
 
 The true acacias are found in warm parts of the world, and yield valuable though usually small 
 timber, which is remarkable for being hard and tough, as Acacia tortuosa, called Cashaw-tree 
 in the West Indies. On the west coast of Africa, Acacia verek has very hard white wood, as 
 well as other species. A. mclanoxylon, black wattle-tree and blackwood, and A. decurrens, 
 green wattle, occur in Hew Holland. 
 
 In India, Acacia arabica and farnesiana, commonly called bubool, A. speciosa, and A. sundra, 
 yield timber valued for different purposes. Many of these trees exude gum, and their bark ij 
 employed in tanning leather. 
 
 Acacia, Arise, the common acacia or locust-tree. See Locust-tree. 
 
 African Black- wood. See Black Botany-Bay Wood. 
 
034 
 
 WOODS, VARIETIES OF. 
 
 Alder, ( Alnus glutinosa,) Europe and Asia. There are other species in North America and the Hima- 
 layas. The common alder seldom exceeds 40 feet in height, is very durable under water, and wa» 
 used for the piles of the Rialto at Venice, the buildings at Ravenna, Ac. : the wood is also much 
 used for pipes, pumps, and sluices. The color of alder is reddish-yellow of different shades, and 
 nearly uniform ; the wood is soft, and the smaller trees are much used for inferior turnery, as tooth- 
 powder boxes, common toys, brushes and bobbins, and occasionally for foundry patterns. The roots 
 and knots are sometimes beautifully veined, and used in cabinet-work. The charcoal of the alder 
 is employed in the manufacture of gunpowder. 
 
 Aloes-wood. See Calembeg. 
 
 Almond-tree, ( Amygdalus communis ,) is very strongly recommended by Desormeaux, as being hard, 
 heavy, oily or resinous, and somewhat pliable ; he says, the wood towards the root so much resem- 
 bles lignum-vitce as to render it difficult to distinguish between them. It is sometimes called false 
 lignum-vitcc, and is used for similar purposes, as handles, the teeth and bearings of wheels, pulleys, 
 Ac., and any work exposed to blows or rough usage. It is met with in the south of Europe, Syria, 
 Barbary, Ac. The wood of the bitter almond, grown in exposed rocky situations, is preferred. 
 
 Amboyna-wood. See Kiabooca-wood. 
 
 Angica-wood. See Cangica-wood. 
 
 Aps. See Poplar. 
 
 Apple-tree, ( Pyrus Malus.) The woods of the apple-trees, especially of the uncultivated, are in gen- 
 eral pretty hard and close, and of red-brown tints, mostly lighter than the hazelnut. The butt of 
 the tree only is used ; it is generally very straight and free from knots up to the crown, whence 
 the branches spring. The apple-tree splits very well, and is one of the best woods for standing 
 when it is properly seasoned ; it is very much used in Tunbridge turnery, for bottle-cases, Ac. : it 
 is a clean-working wood, and being harder than chestnut, sycamore, or lime-tree, is better adapted 
 than they are for screwed work, but is inferior in that respect to pear-tree, which is tougher. The 
 millwright uses the crab-tree for the teeth of mortise-wheels. 
 
 Apri,cot-tree, {Armeniaca vulgaris ,) a native of Armenia, is mentioned in all of the French works on 
 turning, beginning with Bergeron, (1192,) who says the wood of the apricot-tree is very rarely met 
 with sound, but that it is agreeably veined, and better suited to turning than carpentry. He else- 
 where very justly adds, that we are naturally prejudiced in favor of those trees from which we 
 derive agreeable fruits, and expect the respective woods to be either handsome in appearance or 
 agreeable in scent, but in each of which expectations we are commonly disappointed : this applies 
 generally to the orange and lemon trees, and we may add, to the quince, pomegranate, and coffee 
 trees, the vine, and many others occasionally met with, rather as objects of curiosity than as ma- 
 terials applicable to the arts. 
 
 Arbor vitye. The different species of Thuja are called Arbor vita:, and are chiefly found in North 
 America and China. T. occidentals, or American Arbor vit<e, attains a height of from 40 to 50 
 feet, and has reddish-colored, somewhat odorous, very light, soft and fine-grained wood. It is 
 softer than white pine, and much used in house-carpentry, and also for fences. 
 
 The Chinese Arbor vitce, or T. orienlalis, is smaller, but the wood is harder. T. articulata, a 
 native of the north coast of Africa, is the Alerce of the Moors, and was employed in the wood- 
 work of the mosque, now the cathedral, of Cordova. The plant is now called Callitris 
 quadrivalvis. 
 
 Asii, ( Fraxinus cxcelsa ;) Europe and north of Asia; mean size, 38 feet long by 23 inches diameter, 
 sometimes much larger. The young wood is brownish-white with a shade of green ; the old oak- 
 brown, with darker veins. Some specimens from Hungary with a zigzag grain, and some of the 
 pollards, are very handsome for furniture. 
 
 Ash is superior to almost any other timber for its toughness and elasticity ; it is excellent for 
 works exposed to sudden shocks and strains, as the frames of machines, wheel-carriages, agricul- 
 tural implements, the felloes of wheels, and the inside work of furniture, Ac. The wood is split 
 into pieces for the springs of bleachers’ rubbing-boards, which are sometimes 40 feet long; also 
 for handspikes, billiard cues, hammer handles, rails for chairs, and numerous similar works, which 
 are much stronger when they follow the natural fibre of the wood. 
 
 Ash is too flexible and insufficiently durable for building purposes ; the young branches serve 
 for hoops for ships’ masts, tubs, churns, Ac. 
 
 Several species are found in North America : of these it is thought that the white-ash, or Frax- 
 inus amcricana, comes the nearest in quality of wood to the common ash. F. fioribunda and 
 zanthoxyloides are two ashes found in the Himalayas. 
 
 Fraxinus ornus produces manna ; Fraxinus excelsa produces a manna somewhat similar. 
 
 Ash, the Mountain Ash, or Quicken or Rowan tree, Pyrus Aucuparia, grows in almost every 
 soil or situation, has fine-grained hard wood, which may be stained of any color, and takes a 
 high polish, and is applied to the same purposes as the wood of the Beam and Service trees. 
 See Service-tree. 
 
 Aspen. See Poplar. 
 
 Barberry- wood, ( Berberis vulgaris,) is of small size, generally about 4 inches diameter ; the rind is 
 yellow, and about half an inch thick : the wood resembles elder, and is tolerably straight and 
 tenacious. 
 
 Barwood, Africa. Two kinds are imported from Angola and Gaboon respectively, in split pieces 4 to 
 5 feet long, 10 to 12 inches wide, and 2 to 3 inches thick. It is used as a red dyewood — the wood 
 is dark-red, but the dye rather pale ; it is also used for violin-bows, ramrods, and turning. 
 
 Bay-tree. The sweet bay-tree, ( Laurus nobilis,) a native of Italy and Greece, grows to the height ot 
 30 feet, and is an aromatic wood. It is the laurel that was used by the ancients for their military 
 crowns. 
 
WOODS, VARIETIES OF. 
 
 
 Beech. Only one species ( Fagus sylvatica ) is common to Europe ; in England the Buckinghamshire 
 and Sussex beech are esteemed the best. Mean dimensions of the tree, 44 feet long and 27 inches 
 diameter. The color (whitish-brown) is influenced by the soil, and is described as white, brown 
 and black. — ( Tredgold .) 
 
 Beech is used for piles in wet foundations, but not for building; it is excellent from its uniform 
 texture and closeness for in-door works, as the frames of machines, common bedsteads and furniture , 
 it 'is very much used for planes, tools, lathe-chucks, the keys and cogs of machinery, shoe-lasts, 
 pattens, toys, brushes, handles, &c. Carved moulds for the composition ornaments of picture-frames, 
 and for pastry, and large wooden types for printing, are commonly made of beech : the wood is 
 often attacked by worms when stationary, as in framings, but tools kept in use are not thus 
 injured. 
 
 Beech is stained to imitate rosewood and ebony, and it is considered to be almost chemically 
 free from foreign matters ; for example, the glass-blowers use the wood almost exclusively in weld- 
 ing, or fusing on, the handles of glass jugs, which process fails when the smallest portion of sulphur, 
 <fcc., is present : oak is next in estimation for the purpose. 
 
 The white-beech of North America, Fagus sglvestris, is little valued in this country ; the bark, 
 however, is employed in tanning. 
 
 Beefwood. Red-colored woods are sometimes thus named, but it is generally applied to the Botany- 
 bay oak — which see. 
 
 Betle-nuts, or Areca-nuts, are the fruit of the Areca catedru, or Faufel ; they have a thin, brown 
 rind, and in size are intermediate between walnuts and hazelnuts ; their general substance is of a 
 faint oily-gray color, thickly marked with curly streaks of dark-brown or black. The betle-nuts, 
 although softer, resemble ivory, as regards the art of turning ; they are made into necklaces, the 
 tops of walking-sticks, and other small objects. The substance of the betle-nut,, together with 
 quicklime, is chewed by the generality of the natives of India. 
 
 Fig. 3947 is the section of the betle-nut full size, and at right angles to the stalk. Fig. 3948 is 
 the section through the line of the stalk, which shows the central cavity. Externally the marks 
 constitute a tortuous running pattern, as seen in the turned knob, Fig. 3949. 
 
 3948. 3949. 
 
 Birch wood. A forest-tree common to Europe and North America ; the finest is from Canada, St. 
 John’s, and Pictou. It is an excellent wood for the turner, being light-colored, compact, and easily 
 worked : it is in general softer and darker than beech, and unlike it in grain. 
 
 Birchwood is not very durable ; it is considerably used in furniture. Some of the wood is almost 
 as handsomely figured as Honduras mahogany, and when colored and varnished is not easily dis- 
 tinguished from it. The bark of the birch-tree is remarkable for being harder and more durable 
 than the wood itself : amongst the Northern nations it is used for tiles for roofs, for shoes, hats, ifcc., 
 and in Canada for boats. The Russians employ the tan of one of the birch-trees to impart the 
 scent to Russia leather, which is thereby rendered remarkably durable. The inner bark is used 
 for making the Russia mats. 
 
 The English birch is much smaller than the American, and lighter in color ; it is chiefly used for 
 common turnery. Some of the Russian birch (called Russian maple) is very beautiful, and of a 
 full yellow color. 
 
 Betula alba is the common birch of Europe, and the most common tree throughout the Russian 
 Empire. The Russian maple of commerce is thought to be the wood of the birch. Betula 
 lenta, mahogany birch and mountain mahogany of America, has close-grained, reddish-brown 
 timber, which is variegated, and well adapted to cabinet-work. It is exported in considerable 
 quantities to England under the name of American birch. 
 
 Betula excelsa, tall, also called yellow-birch, has wood much like the last, and B. nigra, or black, 
 is also much esteemed. B.papyracea, paper or canoe birch, is employed by the North Amer- 
 ican Indians in constructing their portable canoes. B. Bhojputtra is a Himalayan species, of 
 which the bark is used for writing upon, and for making the snakes of hookahs. 
 
 Bitter-nut wood, a native of America, is a large timber wood measuring 30 inches when squared, plain 
 and soft in the grain, something like walnut. 
 
 Juglans amara, white or swamp hickory or bitter-nut, and J. aquatica, or water bitter-nut 
 hickory, are probably the trees which yield this wood. 
 
 Brack Botany-Bay wood, called also African Blackwood, is perhaps the hardest and also the most 
 wasteful of all the woods ; the billets are veiy knotty and crooked, and covered with a thick rind 
 of the color and hardness of boxwood; the section of the heart-wood is very irregular, and mostly 
 either indented from without, or hollow and unsound from within ; many of the pieces have the 
 irregular scrawling growth that is observed in the wood of the vine. The largest stem of Black 
 Botany-Bay wood we have ever seen, measured transversely 11 inches the longest and 7J the short- 
 est way, but it would only produce a circular block of 5 inches, and this is fully two or three times 
 the ordinary size 
 
 3947. 
 
D36 
 
 WOODS, VARIETIES OF. 
 
 The wood, when fresh cut, is of a bluish-black, with dark-gray streaks, but soon changes to an 
 intense jet black ; of the few sound pieces that are obtained, the largest may perhaps be five 
 inches, but the majority less than two inches in diameter. It is most admirably suited to eccentric 
 turning, as the wood is particularly hard, close, free from pores, but not destructive to the tools, 
 from which, when they are in proper condition, it receives a brilliant polish. It is also considered 
 to be particularly free from any matter that will cause rust, on which account it is greatly esteemed 
 for the handles of surgeons’ instruments. 
 
 The exact locality of this wood has long been a matter of great uncertainty. It has been con- 
 sidered to be a species of African ebony, but its character is quite different and peculiar ; we have 
 however recently heard, from two independent sources, that it comes from the Mauritius, or Isle oi 
 France. Col. Lloyd says the wood is there called Cocobolo prieto ; that it is not the growth of the 
 Mauritius, but of Madagascar, to the interior of which island Europeans are not admitted ; and that 
 it is brought in the same vessels that bring over the bullocks, for the supply of food. The stone- 
 masons of the country use splinters of it as a pencil for marking the lines upon their work ; it 
 makes a dark-blue streak not readily washed off by rain. 
 
 We have only met with one specimen of this wood in the numerous collections we have searched, 
 namely, in Mr. Fincham’s: he assures us that his specimen grew in Botany Bay, and was brought 
 direct from thence, with several others, by Captain Woodroff'e, It. N. As we have recently purchased 
 a large quantity imported from the Mauritius, it is probable that this wood, in common with many 
 others, may have several localities. 
 
 It would be very desirable for the amateur turner that the wood should be selected on the spot, 
 and the better pieces alone sent, as a large proportion is scarcely worth the expense of shipment, 
 but the tine pieces exceed all other woods for eccentric-turned works. 
 
 Blue Gumwood. See Gumwood. 
 
 Botany-Bay Oak, sometimes called Beefwood, is from Mew South Wales ; it is shipped in round logs, 
 from 9 to 14 in. diam. In general color it resembles a full red mahogany, with darker red veins ; 
 the grain is more like the evergreen oak than the other European varieties, as the veins are small, 
 slightly curled, and closely distributed throughout the whole surface. It is used in veneer for the 
 backs of brushes, Tunbridge ware, and turnery ; some specimens are very pretty. 
 
 The trees called oaks in New South Wales do not belong to the genus Quercus, like the European, 
 North American, and Himalayan oaks. There, the tree called Forest Oak, is Casuarina toru- 
 losa ; Swamp Oak is C. paludosa ; He-Oak is C. equisiti folia ; while C. stricta is called She- 
 Oak, and also Beefwood. 
 
 Boxwood ( Buxus sempervirens ) is distinguished as Turkey and European boxwood. The former is 
 imported from Constantinople, Smyrna, and the Black Sea, in logs felled with the hatchet, that 
 measure from 2 to 6 ft. long, and 2-J- to 14 in. diam. The wood is yellow, inclining to orange ; it has 
 a thin rind with numerous small knots and wens ; some of it is much twisted, and such pieces do 
 not stand well when worked; on the whole, however, it is an excellent, sound, and useful 
 wood. 
 
 Boxwood is much used for clarionets, flutes, and a great variety of turned works ; it makes 
 excellent lathe-chucks, and is selected by the wood-engraver to the exclusion of all other woods. 
 It is also used for carpenters’ rules and drawing-scales ; although lancewood, satin-wood, and elder, 
 are sometimes substituted for it. Boxwood is particularly free from gritty matter, and on that 
 account its sawdust is much used for cleaning jewelry ; it is frequently mentioned by the iioman 
 authors as a wood in great esteem at the period in which they wrote. 
 
 Some of the boxwood is as handsomely mottled as flue satin-wood ; but it differs much in color, 
 apparently according to the age and season at which it is cut, as only a small portion of the Turkey 
 boxwood is of the full yellow so much admired, 
 
 European boxwood is imported from Leghorn, Portugal, &c. The English boxwood is plentiful 
 at Boxhill in Surrey, and in Gloucestershire ; it is more curly in growth, softer and paler than the 
 Turkey boxwood; its usual diameters are from 1 to 5 in.; it is used for common turnery, and is 
 preferred by brass-finishers for their lathe-chucks, as it is tougher than the foreign box and bears 
 rougher usage. It is of very slow growth, as in the space of 20 to 25 years it will only attain a 
 diameter of to 2 inches. A similar wood, imported from America under the name of Tugmutton, 
 was formerly much used for making ladies’ fans. 
 
 Murraya, ( JIackay B. fr. Tavoy,) specimen of Dr. Wallich’s and of Captain Baker’s Collection 
 of Indian woods, and the Garipe apugne bravo , from the Brazils, seem fully equal to boxwood in 
 most respects. 
 
 Buxus sempervirens , or common evergreen box, is found throughout Europe, attaining a height 
 sometimes of from 15 to 20 feet. Turkey box is yielded by Buxus balearica, which is found 
 in Minorca, Sardinia, and Corsica, and also in both European and Asiatic Turkey. 
 
 A new species has lately been introduced from the Himalayas, Buxus emarginatus, of Dr. 
 Wallicli: this is found of considerable size and thickness, and the wood appears as good and 
 compact as that of the boxwood in use in Europe. Royle, Illust. Himal. Bot. p. '321. On actual 
 comparison the Himalayan boxwood is found to be softer than the common kinds, but is like 
 them in other respects. 
 
 Brazil-wood, called also Pernambuco, was supposed by Dr. Bancroft to have been known as a red 
 dyewood before the discovery of the Brazils, which country, he says, was so named by Europeans 
 from its abounding in this wood. The best kind is from Pernambuco, where it is called Pao da 
 rainha, or queen’s-wood, and by the natives Ibirapitanga ; it is also found in the West Indies 
 generally, and is often called Pernambuco-wood. The tree is large, crooked, and knotty, and the 
 bark is so thick that the wood only equals the third or fourth of the entire diameter ; the leaves 
 are of a beautiful red, and exhale an agreeable odor. The Pao da rahiha grows to the diameii-t 
 
WOODS, VARIETIES OF. 
 
 937 
 
 of 15 or 1G inches, the Pao Brazil, an inferior kind, to 50 or 60 in. Brazil-wood is a royal monop- 
 oly, and the best quality has the imperial brand mark at the end ; it is shipped in trimmed sticks, 
 from 1 to 4 in. diam. and 3 to 8 ft. long, and its color becomes darker by exposure to the air. Its 
 principal use is for dyeing ; the best pieces are selected for violin-bows and turning. 
 
 Ccesalpinia echinata, the Ibirapitanga of Piso, yields the Brazil-wood of commerce. De Candolle 
 inquires whether it is not rather a species of Guilandina. C. crista, a native of the West 
 Indies, is called Bresillet, because its wood is reddish-colored like Brazil-wood. C. Sapan is 
 a native chiefly of the Asiatic Isles and of the Malayan Peninsula ; its wood is like Brazil- 
 wood, and well known in commerce as Sapan-wood. 
 
 Braziletto is quite unlike the Brazil-wood ; its color is ruddy orange, sometimes with streaks ; it is 
 imported from Jamaica in sawn logs from 2 to 6 ft. long and 2 to 8 in. diam., with the bark (which 
 is of the ordinary thickness) left on them; and also from New Providence, in small cleaned sticks. 
 Braziletto is thought to be an inferior species of Brazil-wood ; it is principally used for dyeing, also 
 for turnery and violin-bows. 
 
 It is considered to be botanically allied to the above, and is called Ccesalpinia braziliensis, a 
 native of the West Indies, but also found in Brazil. 
 
 Bullet-wood, from the Virgin Isles, West Indies, is the produce of a large tree, with a white sap; the 
 wood is greenish-hazel, close and hard. It is used in the country for building purposes, and resem- 
 bles the Greenheart. 
 
 The name of Bullet-wood is perhaps taken from the Bois de balle or Bullet-wood of the French, 
 Guarea trichilioides, which in Jamaica is called musk or alligator wood. Bullet is perhaps a 
 change from Bully-wood, which is that of the bully-tree, called also Naseberry bullet-tree, or 
 Achras Sapota of botanists, described as one of the best timber-trees. The bully-tree of 
 Guiana is also an Achras. The bastard bully-trees of Jamaica are species of Bumelia. 
 
 Bullet-wood, another sjrecies so called, is supposed to come from Berbice ; its color is hazel-brown, of 
 an even tint without veins ; it is a very close, hard, and good wood, well adapted to general and 
 to eccentric turning, but is not common. 
 
 The latter agrees pretty closely with a wood described by Dr. Bancroft as Bow-wood, ovWasceba, 
 of Guiana. 
 
 Different specimens marked Naseberry bullet-wood, and one of an iron-wood, were exceedingly 
 near to the above, if not identical with it, and the Bull Ploof and Bread-nut Heart, all from Jamaica, 
 approached more distantly. 
 
 Button-wood Tree. See Plane-tree. 
 
 Cabbage-wood. See Partridge-wood. 
 
 Calamander, Biospt/ros hirsuta. See Coromandel. 
 
 Calamberrl See Coromandel. 
 
 Calembeg. A wood similar to Sandal-wood in grain, and similarly, but less powerfully, scented ; its 
 color is olive-green, with darker shades. It appears entitled to the name of Green Sandal-wood. 
 
 Calembeg, or Calambac, sometimes called Aloes-wood, is the Agallochum of the ancients, and 
 the Agila or Eagle-wood of the moderns. It is produced in Siam and Silhet by Aquilaria 
 Agallocha. 
 
 Campeachy Logwood. See Logwood. 
 
 Camphor-wood is imported from China, the East Indies, and Brazils, in logs and planks of large size ; 
 it is a coarse and soft wood, of a dirty grayish-yellow color, sometimes with broad iron-gray streaks, 
 and is frequently spongy, and difficult to work. It is principally used in England for cabinet-work 
 and turnery, on account of its scent. 
 
 The Camphor-tree of Sumatra is Dryobalanops Camphora, of which the wood is hard, compact, 
 and brownish-colored ; there is a genuine specimen in the museum of King’s College, Loudon. 
 The fragrant light-colored soft wood of which the trunks and boxes from China are made, is 
 supposed to be that of the Camphor-tree of Japan, Laurus Camphora, now Camphora officinalis. 
 One or more of the tribe of Laurels yield the Sirwabqli wood of Guiana, which is light, fragrant, 
 and much used in the building of boats. 
 
 Camwood, an African dyewood, is shipped from Rokella, Sierra Leone, <fcc., in short logs, pieces, roots, 
 and splinters. When first opened, it is tinted with red and orange ; the dust is very pungent, like 
 snuff; it would be a beautiful wood if it retained its original colors, but it changes to dark red, 
 inclining to brown. Camwood is the best and hardest of the red dyewoods ; it is very fine and 
 close in the grain, and suitable to ornamental and eccentric turning. 
 
 Canary-wood from the Brazils, Para, <fec. ; known at the Isthmus of Darien as Amarillo. It is imported 
 in round logs from 9 to 14 in. diam., and sometimes in squared pieces. The wood is of a light 
 orange color, and generally sound ; it is straight and close in the grain, and very proper for cabinet 
 work, marquetry, and turnery ; is similar, if not the same, to a wood called Vantatico and Vigniatico, 
 corrupted from Vinliatico, a Portuguese name for several yellow woods, besides that imported from 
 the Brazils under the same name. 
 
 Laurus indica, or Royal Bay, is a native of the Canary Isles. The wood is of a yellow coloi 
 not heavy, but well suited to furniture ; it is called Vigniatico in the island of Madeira. 
 
 Caxgica-wood, from the Brazils, also called in England Angica, is of the rosewood character, but of a 
 lighter and more yellow brown, less abrupt, and more fringed, sometimes straight in grain and 
 plain in figure. It is imported in trimmed logs from 6 to 10 in. diam., and is used for cabinet-work 
 and turning. 
 
 Cedar. The name cedar has been given to trees of very different natural orders, and has occasioned 
 much confusion. 
 
 The cedar of Lebanon, or great cedar, ( Pinvs Cedrics,) is a cone-bearing, resinous tree, and one 
 of the pines. It is tall and majestic, and grows to a great size ; the mean dimensions of it- 1 trunk 
 
938 
 
 WOODS, VARIETIES OF. 
 
 are 50 feet high and 39 Indies diameter. The wood is of a ridi yellowish brown, straight-grained 
 and it has a peculiar odor. The tree is famous in Scripture for its size and durability, (Ezekiel xxxi 
 3, 5, 8 ;) it was used in the construction of Solomon's temple at Jerusalem, and many Grecian tem- 
 ples and statues. A few fine trees are said still to remain on Mount Lebanon ; but the wood wa» 
 also procured, iu the time of Vitruvius, from other parts of Syria, and from Crete, Africa, &c — 
 Tredgold. 1 
 
 The Pencil cedar is the Juniperus virginiana ; it is also of the same natural order as the pine- 
 tree. It is a native of North America. The grain of the wood is remarkably regular and soft, on 
 which account, principally, it is used for the manufacture of pencils, and from its agreeable scent, 
 for the inside work of small cabinets ; from the same reason it is made into matches for the 
 drawing-room. 
 
 Another species is the Juniperus bermudiana ; it is a much harder and heavier wood than the 
 pencil cedar, with a similar smell and appearance. It was formerly much used in ship-building; 
 many of the timbers of the Spanish ships taken in the last war were of the Bermuda cedar. 
 
 The cedar known to cabinet-makers by the name of Havana cedar, is the wood of the Cedrcla 
 odorata of Linnaeus, and belongs to the same natural order as mahogany, which it resembles, 
 although it is softer and paler, and without any variety of color. It is imported in considerable 
 quantities from the island of Cuba, and is excellent for the insides of drawers and wardrobes : all 
 the cigar-boxes from Havana are made of this kind of cedar ; the wood is brittle and porous. Some 
 kinds of the Havana cedar are not proper for cabinet-work, as the gum oozes out and makes the 
 surface of the work very sticky and unpleasant. 
 
 There is another kind more red in color, called red cedar ; there are also white cedars common 
 to America : one kind is called prickly cedar, from its being covered with spines ; this is very like 
 the white hemlock, and grows to 4 feet diameter, and 60 to 70 feet high, and is much used for 
 railway works. 
 
 Another sort, from New South Wales, is the wood of the Ccdrela Toona ; it is somewhat similar 
 to the Havana, but more red in color, and of a coarser grain ; it sometimes measures 4 feet diam- 
 eter. This kind is also found in the East Indies ; it is in common use in joinery-work. Most of 
 the cedars have been used for ship-building. 
 
 The Himalayan cedar ( Juniperus excclsa ) is harder and less odoriferous than the pencil cedar, 
 but is an excellent light wood between pencil cedar and deal in general character. 
 
 The cedar of Lebanon is usually called Pinus Cedrus, but sometimes Cedrus Li banus ; the lofty 
 Deodara, a native of the Himalayas, with fragrant and almost imperishable wood, and often 
 called the Indian cedar, is sometimes referred to the genus Pinus , and sometimes to that of 
 Cedrus or Larix, with the specific name of Deodara. 
 
 The wood of several of the Conifers; is, however, called cedar. The wood of Juniperus vir- 
 giniana is called red or pencil cedar, and that of J. bermudiana is called Bermuda cedar ; of 
 J hcm-badensis is called Barbadoes cedar ; while the Juniper of the North of Spain, and South 
 of France, and of the Levant, is called J. oxycedrus : the white cedar of North America, a 
 less valuable wood than the red cedar, is yielded by Cuprcssus Thyoides, and the cedar-wood 
 of Japan, according to Thunberg, is a species of cypress. 
 
 The name cedar is, however, applied to a number of woods in our different colonies, which are 
 in no way related to the Coniferm : thus the cedar of Guiana is the wood of Idea altissima, 
 white wood or white cedar of Jamaica is Bignonia leucoxylon, and bastard cedar is Guazuma 
 ulmifolia. In New South Wales, again, the term white cedar is applied to Melia Azedera.ch, 
 and red cedar to that of Flindersia australis, as well as to the wood of the Toon-tree, or 
 Cedrcla Toona. 
 
 Jherb.y-tk.ee is a hard, close-grained wood, of a pale red brown, that grows to the size of 20 or 24 
 inches, but it is more Usually of half that size. When stained with lime, and oiled or varnished, 
 it closely resembles mahogany ; it is much used for common and best furniture and chairs, and is 
 one of the best brown woods of the Tunbridge turners. The wood of the black-heart cherry-tree 
 is considered to be the best. The Spanish American cherry-tree is very elastic, and is used for 
 felucca masts. 
 
 Cerasus avium is the wild cherry. C. duracina is the heart cherry or Bigarreau. The wood of 
 C. Mahaleb is much used by the French, and is called bois de Sainte Ijucie. 
 
 Chestnut ( Castanea vesca ) is common to Europe ; mean size 44 feet high, 37 inches diameter; is very 
 long-lived and durable. The sweet, or Spanish chestnut, is very much like oak, and is sometimes mis- 
 taken for it; it was formerly much used in house-carpentry and furniture. The young wood is 
 very elastic, and is used for the rings of ships’ masts, the hoops for tubs, churns, &c., but the old 
 wood is considered to be rather brittle. See Horse-chestnut. 
 
 The edible or sweet chestnut is the Castanea vesca , but the horse-chestnut (which see) belongs to 
 a very different genus. The wood, formerly much used in house-building and carpentry, and 
 which, famed for its durability, has been mistaken for chestnut, is now considered to be that of 
 an oak, Quercus sessilifiora. 
 
 Cocoa- wood, or Cocus, is imported from the West Indies in logs from 2 to 8 inches diameter, sawn to 
 the length of 3 to 6 feet, tolerably free from knots, with a thick yellow sap : the heart, which is 
 rarely sound, is of a light yellow brown, streaked, when first cut, with hazel and darker brown, 
 but it changes to deep brown, sometimes almost black. Cocoa-wood is much used for turnery of 
 all kinds, and for flutes ; it is excellent for eccentric turning, and in that respect is next to the 
 African blackwood. 
 
 An apparent variety of cocoa-wood, from 2 to 6 or 7 inches diameter, with a large proportion of 
 hard sap of the color of beechwood, and heartwood of a chestnut-brown color, is used for tree- 
 nails and pins for ship-work, and purposes similar to lignum-vitie, to which it bears some resem- 
 
WOODS, VARIETIES OF. 
 
 939 • 
 
 blance, although it i3 much smaller, has a rough bark, the sap is more red, and the heart darker 
 and more handsomely colored when first opened than lignum-vitae ; it is intermediate between it 
 and cocoa-wood. Another but inferior wood exactly agrees with the ordinary cocoa-wood, but 
 that the heart is in wavy rings, alternately hard and soft. 
 
 Cocoa-wood has no connection with the cocoanut, which is the fruit of a palm-tree common to 
 the East and West Indies, the Cocos nucifera ; neither can it have any relation to the other endo- 
 genous trees which produce the coquilla-nut, the Attalia funifera according to Martius, and Cocos 
 lapidea of Gasrtner, or of the Cacao Theobroma, or the chocolate-nut tree. 
 
 It is really singular that the exact localities and the botanical name of the cocoa-wood that is so 
 much used, should be uncertain : it appears to come from a country producing sugar, being often 
 imported as dunnage, or the stowage upon which the sugar hogsheads are packed : it is also known 
 as brown ebony, but the Amerimnum Ebenus of Jamaica seems dissimilar. 
 
 The cocus-wood of commerce is not easy to trace to any of the trees of the West Indies ; the 
 cocoa plum is Chrysobalanus Icaco, which forms only a shrub ; Coccoloba uvifera, or mangrove 
 grape-tree, grows large and yields a beautiful wood for cabinet-work, but which is light and 
 of a white color. In appearance and description it comes near to the Greenlieart or Laurns 
 chloroxylon, which is also called Cogwood. 
 
 Oocoanut-tree. See Palms. 
 
 Cocoanut-shell. The general characters of this fruit, the produce of the palm Cocos nucifera, are 
 too well known to need particular description : in India its thick fibrous husk is made into the coir- 
 rope, and in Europe into rope, matting, brushes, <fcc. The substance of the shell is very brittle, 
 and its structure is somewhat fibrous, but it admits of being turned in an agreeable manner. 
 Those shells which are tolerably circular are used for the bodies of cups and vases, the feet and 
 covers being made of wood or ivory. Common buttons are also made of the cocoanut-shell, and 
 are considered better than those of horn, as they do not, like that material, absorb moisture, which 
 causes them to swell and twist. 
 
 Cocus. See Cocoa-wood. 
 
 Coffee-tree, ( Coffea arabica.) The wood is of a light greenish-brown or dusky -yellow, with a bark 
 externally resembling boxwood, but thicker and darker ; it has no smell, and but little taste. The 
 tree does not grow more than a few feet high, and it is cut down in the plantations to five or six 
 feet, and is not therefore useful in manufactures. 
 
 The tree called Kentucky coffee-tree, or hardy bonduc, is very different from the common coffee : 
 it forms' a large tree called Gymnocladus canadensis ; the wood is compact, of a rosy hue, and used 
 by cabinet-makers. 
 
 Coral-wood, says Bergeron, is so named from its color. When first cut it is yellow, but soon changes 
 to a fine red or superb coral; it is hard, and receives a fine polish : he also speaks of a damasked 
 coral-wood. It is difficult to associate these with the red woods ; they are, perhaps, from the de- 
 scriptions, nearest to the camwood from Africa. 
 
 The coral-tree, so called from the color of its flowers, is Efythrina Corallodendron ; but the 
 bois de corail of the French is the wood of Adenanthera pavonina, which is hard, reddish- 
 • ' colored, and sometimes confounded with red sanders-wood. 
 
 Coquill a-nuts are produced in the Brazils by Attalia funifera, according to Martius, or the Cocos 
 lapidea of Gsertner ; the latter title is highly descriptive. The coquilla-nut is represented in sec- 
 tion, half size, in Fig. 3950 : the shell is nearly solid, with the exception of the two separate cavities 
 represented, each containing a hard, flattened, greasy kernel, generally of a disagreeable flavor : 
 the cells occasionally inclose a grub or chrysalis similar to that figured, which consumes the fruit 
 
 3950. 3951. 3952. 
 
 The passages leading into the chambers are lined with filaments or bristles, and this end of the 
 shell terminates exteriorly in a covering of these bristles, which conceal the passages ; this end is 
 consequently almost useless, but the opposite is entirely solid, and terminates in the pointed attach- 
 ment of the stalk. Sometimes the shell contains three kernels, less frequently but one only, and 
 we have heard of one coquilla-nut that was entirely solid. The substance of the shell is brittle, 
 hard, close, and of a hazel-brown, sometimes marked and dotted, but generally uniform. Under 
 the action of sharp turning tools it is very agreeable to turn, more so than the cocoanut-shell , it 
 may be eccentric-turned, cut into excellent screws, and admits of an admirable polish, and of being 
 lackered. On the whole it is a very useful material, and suitable for a great variety of smaD 
 
940 
 
 WOODS, VARIETIES -OF. 
 
 ornamental works, both turned and filed ; coquilla-nuts are extensively manufactured into th* 
 knobs of umbrellas and parasols, small toys, dzc. 
 
 Coromandel, or Calamander, the produce of Ceylon, and the coast of India, is shipped in logs and 
 planks from Bombay and Madras. The figure is between that of rosewood and zebra-wood ; the 
 color of the ground is usually of a red hazel-brown, described also as chocolate-brown, with black 
 stripes and marks. It is said to be so hard as almost to require grinding rather than cutting ; this 
 is not exactly true, as the veneer saws cut it without particular difficulty : it is a very handsome 
 furniture wood, and turns well ; it is considered to be a variety of ebony. 
 
 There are three varieties of Coromandel: the Calamander or Coromandel, which is the darkest, 
 and the most commonly seen in this country, the Calemberri , which is lighter colored and striped, 
 and the Omander, the ground of which is as light as English yew, but of a redder cast, with a few 
 slight veins and marks of darker tints. The wood is scarce, and almost or quite limited to Ceylon ; 
 it grows between the clefts of rocks ; this renders it difficult to extract the roots, which are the 
 most beautiful parts of the trees. 
 
 The Calamauder-wood tree is Diospyros hirsuta, and Kadum Beriya is I). Ebcnaster, according 
 to Moore’s Catalogue of Ceylon Plants, and therefore of the same genus as the true ebony. 
 
 Coromandel, falsely so called, has a black ground, and is either striped, mottled, or dappled, with light 
 yellow, orange, or red ; it is a description of accidental or imperfect East Indian black ebony. 
 Some of the pieces are very handsome ; it is used for similar purposes to the true Coromandel, 
 from which, however, it is entirely different, and generally inferior, although it is considered a 
 variety of the same group. 
 
 Corosos, or Ivory-nuts, are produced by Phyteleplias macrocarpa, growing in Central America, and 
 Columbia. — {Humboldt.) They are described as seeds with osseous albumen ; the tree is a genus 
 allied to the Pandanece, or Screw Pines, and also to the Palms. The nuts are of irregular shapes, 
 from one to two inches diameter, and when inclosed in their thin husks, they resemble small pota- 
 toes covered with light-brown earth : the coat of the nut itself is of a darker brown, with a few 
 loose filaments folded upon it. The internal substance of the ivory-nut resembles white wax rather 
 than ivory; it has, when dried, a faint and somewhat transparent tint, between yellow and blue, 
 but when opened it is often almost green from the quantity of moisture it contains, and in losing 
 which it contracts considerably. Each nut has a hole, which leads into a small, central, angular 
 cavity ; this, joined to the irregularity of the external form, limits the purposes to which they are 
 applied — principally the knobs of walking-sticks, and a few other small works. Fig. 8951 is the 
 section of the ivory-nut at right angles with the stalk, and half size ; and Fig. 8952 is the section 
 through the stalk itself, which proceeds from s. 
 
 Cowdje. See Pines. 
 
 Cr/.b-tree, the wild Apple-tree; principally used by millwrights for the teeth of wheels. See 
 Apple-tree. 
 
 Cypress-tree. Of this there are many varieties ; the principal are the Cuvressus sempervirens, and 
 the white cypress or white cedar of North America, the Cupressus Tliyoides ; the latter is much 
 used as a timber wood ; it is an immense tree, and is considered to be more durable even than 
 the cedar of Lebanon. The Cupressus sempervirens is said to have been much used bj^ the 
 ancients ; by the Egyptians for the cases for some of their mummies, by the Athenians for 
 coffins, and for the original doors of St. Peter’s at Rome, which, on being replaced after six hun- 
 dred years by gates of brass, were found to be perfectly free from symptoms of decay, and 
 within, to have retained part of the original odor of the wood. — Tredgold. 
 
 It is probable that the wood of Thuja articulata (see Arbor vitce) w*as also used by the an- 
 cients, and has sometimes been mistaken for that of Cypress. 
 
 Deal. See Pines. 
 
 Dogwood, a small underwood, which is so remarkably free from silex, that little splinters of the 
 wood are used by the watchmaker for cleaning out the pivot-holes of watches, and by the opti 
 cian for removing the dust from small deep-seated lenses ; dogwood is also used for butchers’ 
 skewers, and tooth-picks. 
 
 The charcoal of the black dogwood is employed in the manufacture of the best sporting gun 
 powder, alder and willow charcoal for the government powder. — Wilkinson' s Engines of War 
 1811. 
 
 Cornns sanguined is the wild cornel or common dogwood, C. mas. is the male dogwood or 
 Cornelian cherry, while C.florida is an American species ; others are found in the Himalayas. 
 The name dogwood is applied in Jamaica to Piscidia Erithrina. 
 
 East Indian Blackwood, ( Dalbergia latifolia,) called Blackwood-tree by the English and Sit Sal 
 by the natives of India, on the Malabar coast, where it grows to an immense size. The wood of 
 the trunk and large branches is extensively used for making furniture ; it is heavy, sinking in 
 water, close-grained, of a greenish or greenish-black color, with lighter-colored veins running in 
 various directions, and takes a fine polish. 
 
 Ebony is described as of several colors, as yellow, red, green, and black. The existence of yellow 
 and red ebonies appears questionable. The black ebony is the kind always referred to when 
 the name is mentioned alone ; in fact, “ as black as ebony” is an old proverb. The wood is 
 surrounded by a white sap 3 or 4 inches thick. The green ebony is an entirely different tree, 
 with a thin smooth bark, growing in the West Indies. 
 
 Three kinds are imported : No. 1, from the Mauritius, in round sticks like scaffold poles, they 
 seldom exceed 14 in. diameter ; No. 2, the East Indian, which grows in Ceylon, the East India 
 islands, and on the continent of India ; this is mostly shipped from Madras and Bombay in logs 
 from 6 to 20 and sometimes even 28 in. diameter, and also in planks; and No. 3, tie African 
 ebony, shipped from the Cape of Good Hope in billets, the general sizes of which are from 3 to 
 
WOODS, VARIETIES OF. 
 
 941 
 
 6 ft. long, 3 to 6 in. wide, and 2 to 4 in. thick; these are rent out of the trees, and are thence 
 often called billet-wood. 
 
 No. 1, the Mauritius, is the blackest and finest in the grain, as well as the hardest and most 
 beautiful of the three, but also the most costly aud unsound ; No. 2, the East Indian, is lesa 
 wasteful, but of an inferior grain and color to the above ; and No. 3, the African, is the least 
 wasteful, as all the refuse is left behind, and all th&t is imported is useable, but it is the most 
 porous, and' the worst in point of color. 
 
 They are all used for cabinet, mosaic, and turnery works ; also for flutes, the handles of doors, 
 knives, and surgeons’ instruments, and many other purposes. Piano-forte keys are generally made 
 of the East Indian variety. 
 
 The African stands the best, and is the only sort used for sextants. 
 
 Colonel Lloyd says, the Mauritius ebony when first cut is beautifully sound, but that it splits 
 like all other woods from neglectful exposure to the sun. The workmen who ttse it, immerse it 
 in water as soon as it is felled for 6 to 18 months ; it is taken out, and the two ends are secured 
 from splitting by iron rings and wedges. He considers the Mauritius ebony to be the finest, next 
 the Madagascar, and afterwards the Ceylon. 
 
 The black ebony is also met with in South America, but much less generally than in Asia ana 
 Africa. 
 
 The ebony of Mauritius is yielded by Diospyros Ebenus, that of Ceylon is I). Ebenaster, while 
 the ebony-tree of the Coromandel coast is D. melanoxylon ; other species, as I>. tomentosa 
 and I). Boylei, yield ebony on the continent of India. The tree yielding the African ebony 
 is not ascertained. A kind of ebony is produced by Ameriinnum Ebenus , in the West In- 
 dies, and called Jamaica ebony. 
 
 Mountain Ebony. The different species of Banhinice are so called: B. porrecta grows on 
 the hills in Jamaica, and has wood which is hard and veined with black. 
 
 See Green Ebony and Coromandel. 
 
 Elder, ( Sambucus nigra). The branches of the elder contain a very light kind of pith, which is used 
 when dried for electrical purposes. The surrounding wood is peculiarly strong and elastic. The 
 trunk-wood is tough and close-grained ; it is frequently used for common carpenters’ rules ana 
 inferior t-urnery-work, for weavers’ shuttles, (many of which are also made of boxwood,) for 
 fishermen's netting pins, shoemakers’ pegs, (fee. 
 
 Elm, ( Ulmus ,) a timber-tree, of which there are five species; mean size, 44 ft. long, 32 in. diameter. 
 The heartwood is red brown, darker than oak, the sap yellowish or brownish white .with pores 
 inclining to red ; the wood is porous, cross-grained, and shrinks and twists much in drying. Elm 
 is not liable to split, and bears the driving of nails or bolts better than any other timber, and it 
 is exceedingly durable when constantly wet ; it is therefore much used for the keels of vessels, 
 and for wet foundations, waterworks, piles, pumps, and boards for coffins ; from its toughness, 
 elm is selected for the naves of wheels, shells for tackle-blocks, and sometimes for the gunwales 
 of ships, and also for many purposes of common turnery, as it bears very rough usage without 
 splitting. 
 
 Wych Elm. This sometimes grows to the height of 10 feet, and the diameter of 3J feet ; the 
 branches are principally at the top, the wood is lighter and more yellow in color than the above, 
 also straighter and finer in the grain. It is tough, similar to young sweet chestnut for bending, 
 and is much used by coachmakers, and by shipwrights for jolly-boats. 
 
 Bock Elm appears very like the last ; it is extensively used for boat-building, and sometimes 
 for archery bows, as it is considered to bend very well. 
 
 Ulmus campestris is the common small-leaved elm, U. effusa is the spreading-branched, U. 
 glabra is the smooth-leaved, and U. montana the Wych elm. Ulmus Americana, or the 
 American elm, is used for the same purposes as the European siiecies, though the wood is 
 inferior in quality. U. fulva and alata are other American species, and several species are 
 found in the Himalayas. 
 irs and Pines. See Pines. 
 
 Eustio is the wood of a species of Mulberry, (Morns tinctorial growing in most parts of South 
 America, the United States, and West Indies. It is a large and handsome tree ; it is shipped in 
 trimmed logs from 2 to 4 ft. long, 3 to 8 in. diameter ; the color of the wood is a greenish- 
 yellow ; it is principally used for dyeing greens and yellows, and also in mosaic cabinet-work and 
 turning. 
 
 Grexadillo, Granillo, or Grenada Oocus, from the West Indies, is apparently a lighter description of 
 the common cocoa or cocus-wood, but changes ultimately to as dark a color, although more slowly. 
 It is frequently imported without the sap. 
 
 The tree yielding this has not been ascertained ; the hois dc Grenadille of the French is also 
 called red ebony by their cabinet-makers. 
 
 Green Ebony, from Jamaica, and the West Indies generally. It is cut in lengths of 3 to 6 ft., has a 
 bark much like cocus, but thinner and smoother ; the heartwood is of a brownish green, like the green 
 fig. It is used for round rulers, turnery, and marquetry-work, and it cleaves remarkably well. 
 The dust is very puugent, and changes to red when the hands are washed with soap and water. 
 The wood is very much used for dyeing, and it contains so much resinous matter, that the negroes 
 in the West Indies employ it in fishing as a torch. The candle-woods of the West Indies obtain 
 their name probably from the same circumstance ; they are allied to the rosewoods, but are ol 
 lighter yellow colors. 
 
 The ebony of Jamaica is Amcrimnum Ebenus, and has been mentioned under Ebony. The 
 wood' is described as being of a fine greenish-brown color, hard, durable, and capable of tak 
 ing a fine polish ; B. leucoxylon of South America yields le hois d'ebene verte. 
 
942 
 
 WOODS, VARIETIES OF. 
 
 Gr.kexhe,\rt ; from Jamaica, Demerara and the Brazils, bears a general resemblance to cocoa-wood 
 both in size and bark, but the latter has a redder tint. Greenheart when first cut is of a light 
 green brown, and striped, but it changes to the color of Lignum-vitce, and is by some considered 
 to be Dernicioua. It is used for turnery and other works, but its texture is coarse, and it will 
 not cleave at all profitably. 
 
 Greenheart used in ship-building is entirely different from the above, and runs into several 
 varieties. 
 
 Dr. Bancroft describes Greenheart, or the Sipicra-t ree, to be in size like the locust-tree, say 60 
 or 70 feet high : there are two species, the black and the yellow, differing only in the color of 
 tiieir bark and wood. He says there is also a purple-heart wood, of a bright crimson color, but 
 which changes to purple, and is esteemed more valuable than the preceding. 
 
 The Greenheart of Jamaica and Guiana is the Laurus Chloroxylon of botanists ; it is also 
 called Cogwood in the former, and Sipicri in the latter locality. 
 
 Gpmwood. or blue Gumwood, is the produce of New South Wales; it is sent over in large logs and 
 planks ; the color is similar to that of dark Spanish mahogany, with a blue, sometimes a purple- 
 gray cast : it is used in ship-building. There is also a variety of a redder tint, called red Gum- 
 wood, which is used for ramrods ; both are also employed by the turner. 
 
 Eucalyptus piperita is the blue gum-tree of New South Wales, while red gum-tree is another 
 species, probably E. resinifera. 
 
 Hackmetack Larch. See Pines. 
 
 Harewood. See Sycamore. 
 
 Haavthorn ( Cratcegus oxyacantha ) has hard wood of a whitish color, with a tinge of yellow; the 
 grain is fine, and the wood takes a good polish ; but being small and difficult to work, it is not 
 much used. 
 
 Hazel, a small underwood, but little used for turning, except for a few toys. It is very elastic, and 
 is used, as well as the ground-ash, for the rods of blacksmiths’ chisels, hoops of casks, <fcc. Its 
 botanical name is Corylus Avellana. 
 
 Hickory, or White Walnut, ( Juglans alba,) is a native of this country ; it is a large tree, sometimes 
 exceeding 3 ft. diameter. The wood of young trees is exceedingly tough and flexible, and makes 
 excellent handspikes, and other works requiring elasticity. The bark of hickory is recommended 
 by Dr. Bancroft as a yellow dye. 
 
 Holly ( Ilex cequifolium) is a very clean, fine-grained wood, the whitest and most costly of those 
 used by the Tunbridge-ware manufacturer, who employs it for a variety of his best works, 
 especially those which are to be painted in water-colors. It is closer in texture than any other 
 English woods, and does not readily absorb foreign matters, for which reason it is used for painted 
 screens, the squares of draft-boards, and for the stringings or lines of cabinet-work, both in the 
 white state and when dyed black, also for some of the inside works of piano-fortes, harps, for 
 calico-printers’ blocks, &c. When larger wood than holly is required, the horse-chestnut is em- 
 ployed, but the latter is much softer. . 
 
 The holly requires very particular care in its treatment: immediately it is felled it is prepared 
 into pieces of the form ultimately required, as planks, veneers, or round blocks for turning. The 
 veneers are hung up separately to dry, as resting in contact even for two or three hours would 
 stain them ; the round blocks are boiled in plain water for two or three hours, and on removal 
 from the copper they are thrown in a heap and closely covered up with sacking to exclude the air, 
 which would otherwise cause them to split. The heap is gradually exposed as it dries ; at the 
 end of about four weeks the pieces look greenish, and are covered with mildew sometimes as 
 thickly as one-sixteenth of an inch ; this is brushed off at intervals of three or four weeks, and in 
 about six months the wood is fit for use. 
 
 Holly is a remarkably tough, clean wood, and is used for chucks ; but this troublesome prepa 
 ration to whiten the wood (and which is not generally practised on other woods) is not then re- 
 quired, although a good boil hastens the extraction of the sap, and the subsequent seasoning of 
 the wood. 
 
 The American species of this genus is the Ilex opaca, opaque-leaved or American holly, of 
 which the wood is employed in turnery and cabinet-making ; there are other species in the 
 Himalayas. 
 
 Hornbeam, (Carpinus Betulus,) sometimes also called yoke-elm, is a very tough and stringy wood, 
 which is used by millwrights for the cogs of wheels, plumbers’ dressers or mallets, and a variety 
 of things required to bear rough usage. Hornbeam is sometimes used for planes ; it turns very well. 
 
 Horse-chestnut (pEsculus hippocastum) has no relation to the Spanish or sweet chestnut, which lat- 
 ter is more nearly allied to the oaks. The horse-chestnut is one of the white woods of the Tun- 
 bridge turner ; it is close and soft, even in the grain, and is much used for brush-backs ; it turns 
 very well in the lathe, and is a very useful wood. It is softer than holly, but is preferable to it for 
 large painted and varnished works, on account of its greatly superior size. It is but little used 
 in this country. 
 
 Horse-flesh Wood, one of the Mangroves, which see. 
 
 Indian Blackwood. See East Indian Blackwood. 
 
 Iron-wood is imported from the Brazils, the East and West Indies, and other countries, in square and 
 round logs, 6 to 9 in. and upwards through. Its colors are very dark browns and reds, sometimes 
 streaked, and generally straight-grained. 
 
 The iron-woods are commonly employed by the natives of uncivilized countries for their sev- 
 eral sharp-edged clubs and offensive weapons ; in England they are principally used for ramrods, 
 walking-sticks, for turning, and various purposes requiring great hardness and durability : the 
 more red varieties are frequently called beefwood. 
 
WOODS, VARIETIES OF. 
 
 943 
 
 Iron-wood is a term applied to a great variety of woods, ill consequence of their hardness, and 
 almost every country has an iron-wood of its own. Mesua ferrea , which has received its 
 specific name from the hardness of its wood, is a native of the peninsula of India and of the 
 islands. 
 
 Metrosidcros vera is called true iron-wood : the Chinese are said to make their rudders and 
 anchors of it, and among the Japanese it is so scarce and valuable, that it is only allowed to 
 be manufactured for the service of their king. The iron-wood of Southern China is Baryxy- 
 lumrufum; of the island of Bourbon Stadmannia Sideroxylon, and of the Cape of Good 
 Hope Sideroxylon melanophleum, which latter is very hard, close-grained, and sinks in 
 water. 
 
 The iron-wood of Guiana is Robinia Panacoco, (of Aublet ;) that of Jamaica is Fagara Pterota, 
 and also Erytliroxylum areolatum , which is also called redwood. JEgiphila mariinicensis, 
 and Cocoloba latifolia, are other West Indian trees, to the woods of which the name of iron- 
 wood has been applied. 
 
 Ostrya virginica, called American hop hornbeam, has wood exceedingly hard and heavy, 
 whence it is generally called iron-wood in this country, and in some places lever-wood. 
 
 Jakwood is the wood of Artocarpus integrifolia, or the entire-leaf bread-fruit tree, a native of India ; 
 is imported in logs from 3 to 5 feet diameter, and also in planks; the grain is coarse and crooked, 
 and often contains sand. The wood is yellow when first cut, but changes to a dull red or ma- 
 hogany color. It is very much used in India for almost every purpose of house-carpentry and 
 furniture. The jakwood is very abundant, and its fruit is commonly eaten by the natives, 
 and also sometimes by Europeans at dessert, with salt and water, like olives. The jakwood is 
 sometimes misnamed orange-wood from its color, and also jackwood, Jaack- wood, and Kutliul. 
 See Baker’s Papers. 
 
 Jackaranda, the Portuguese and continental name for Rosewood, which see. 
 
 Juniper-wood. The wood of all the species is more or less aromatic, and very durable ; they are 
 found in the cold and temperate parts of the world. 'Some have already been mentioned under 
 the head of Cedar. The common juniper, Juniperus communis, has wood which is aromatic, 
 finely veined, and of a yellowish-brown color ; J. excclsa, lofty or Himalayan cedar, is found on 
 those mountains, as well as in Siberia and North America. 
 
 Kiabooca-wood, or Amboyna-wood, imported from Sincapore, appears to be the excrescence or burr 
 of some large tree ; it is sawn off in slabs from 2 to 4 ft. long, 4 to 24 in. wide, and 2 to 8 in. 
 thick ; it resembles the burr of the yew-tree, is tolerably hard, and full of small curls and knots ; 
 the color is from orange to chestnut-brown, and sometimes red-brown. It is a very ornamental 
 wood, that is also much esteemed in China and India, where it is made into small boxes and 
 writing-desks, and other ornamental works, the same as by ourselves. 
 
 The Kiabooca is said by Prof. Reinwardt, of Leyden, to be the burr of the Plerosperrnum in- 
 dicum ; by others that of Pterocarpus draco, from the Moluccas, the island of Borneo, Amboyna, 
 <fcc. The native name appears, from Mr. Wilson Saunders’ specimen, to be Serioulcut : the wood 
 itself is of the same color as the burr, or rather lighter, and in grain resembles plain mahogany. 
 
 “ The root of the cocoanut-tree is so similar, when dry and seasoned, to the ‘ bird’s-eye’ part 
 of the wood here termed kiabooca, that I can perceive no difference ; the cocoa has a tortuous 
 and silky fracture, almost like indurated asbestos.” — Col. G. A. Lloyd. 
 
 The comparison of the palmwood with the kiabooca renders the question uncertain, as amongst 
 the multitudes of ordinary curly woody fibres, that one cannot account for in a palm, there are 
 a few places with soft friable matter much resembling its cement. 
 
 Eingwood, called also Violet-wood, is imported from the Brazils, in trimmed logs from 2 to 1 in. 
 diameter, generally pipy, or hollow in the heart. It is beautifully streaked in violet tints of dif- 
 ferent intensities, finer in the grain than rosewood, and is principally used in turning and small cab- 
 inet-work; being generally too unsound for upholstery. It is perhaps one of the most beautiful • 
 of the hard woods in appearance. 
 
 Kourie. See Pines. 
 
 Laburnum ( Cytisus Laburnum ) possesses poisonous seeds, and a small dark greenish-brown wood, 
 that is sometimes used in ornamental cabinet-work and marquetry. Mr. Aikiu sayfe : “ In the 
 Laburnum there is this peculiarity, which I have not observed in any other wood, namely, that 
 the medullary plates, which are large and very distinct, are white, whereas the fibres are a dark 
 brown; a circumstance that gives quite an extraordinary appearance to this wood.” 
 
 The Alpine laburnum, with blackish wood, is Cytisus alpinus. 
 
 Lancewood is imported in long poles from 3 to 6 in. diameter from Cuba and Jamaica ; it has a thin 
 rind, externally similar to that of cocoa-wood ; it is called one of the rough-coated woods, and has 
 a bark distinct from the sap-wood, but together they are very thin. Lancewood is of a paler 
 yellow than box, and rends easily ; it is selected for elastic works, such as gig-shafts, archery 
 bows and springs ; these are bent by boiling or steaming ; lancewood is also used for surveyors’ 
 rods, billiard-cues, and for ordinary rules, which are described as being made of boxwood. 
 
 The lancewood of Jamaica is Guatteria virgata, formerly Uvaria l-anccolata. That of Guiana 
 is an Anonaceous plant, and probably the same species. 
 
 Larch. See Pines. 
 
 Letter-wood. See Snakewood. 
 
 Lemon-tree. See Orange-tree. 
 
 LEorARD-wooD. See Palms. 
 
 Ltc.num-vit/e, or Guaiacum, is a very hard and heavy wood. It is shipped from Cuba, Jamaica, St. 
 Domingo, and New Providence, in logs from 2-J- to 36 in. diameter, and is one of the heaviest of 
 the woods. It grows in the Isthmus of Darien to the size of 5 or 6 ft., and is there calle 1 Gual- 
 
944 
 
 WOODS, VARIETIES OE. 
 
 lacan, and is one of the most abundant woods of the country. When first cut, it is soft 
 and easily worked, but it becomes mucli harder on exposure to the air. The wood is cross 
 grained, covered with a smooth yellow sap like box, almost as hard as the wood, which is of a 
 dull brownish-green, and contains a large quantity of the gum guaiacum, which is extracted for 
 the purposes of medicine. Lignum-vitae is much used in machinery, Ac., for rollers, presses, mills, 
 pestles and mortars, sheaves for ship-blocks, and a great variety of other works requiring hard- 
 ness and strength. It was employed by the Spaniards for making gun-carriages and wheels. 
 
 The fibrous structure of this wood is very remarkable : the fibres cross each other sometimes as 
 obliquely as at an angle of 30 degrees with the axis, as if one group of the annual layers wound 
 to the right, the next to the left, and so on, but without much apparent exactitude. 
 
 The wood can hardly be split, it is therefore divided with the saw; and when thin pieces, 
 such as old sheaves, are broken asunder, they exhibit a fracture more like that of a mineral than 
 an ordinary wood. The chips, and even the corners of solid blocks, may be lighted in the candle, 
 and will burn freely from the quantity of gum they contain, which is most abundant in the 
 heart- wood. 
 
 The Bahama lignum-vitas has a very large proportion of sap-wood ; pieces of 8 or 10 inches 
 diameter have heart-wood that scarcely exceeds 1 or 2 inches diameter. One variety of cocoa- 
 wood, and also the almond-wood, are somewhat similar to lignum-vitse. 
 
 There are two species, Guaiacum officinale and G. sanctum , both of which probably yield the 
 lignum-vitse of commerce. This name is also sometimes applied to the wood of Arbor vitce. 
 
 Lime-tree, called also the Linden-tree, Tilia. This wood is very light-colored, fine and close in the 
 grain, and when properly seasoned it is not liable to split or warp. It is nearly or quite as soft 
 as pine, and is used in the construction of piano-fortes, harps, and other musical instruments, and 
 for the cutting-boards for curriers, shoemakers, Ac., as it does not draw or bias the knife in any 
 direction of the grain, nor injure its edge ; it turns very cleanly ; this wood has recently been 
 used for the frames of the best japanned chairs inlaid with mother-of-pearl. Lime-tree is par- 
 ticularly suitable for carving, from its even texture and freedom from knots : the works of Gib- 
 bons, at Windsor Castle and St. Paul’s, London, are of lime-tree. 
 
 The lime-tree, Tilia europea :, is usually divided into several species : as T. intermedia , micro- 
 phylla , rubra, and platyphylla. 
 
 Locust-tree. The locust-tree of North America is Robinia pscudacacia. The wood is greenish-yel- 
 low, with a slight tinge of red in the pores ; it is u=ed like oak. Locust is much esteemed for tree- 
 nails for ships, and for posts, stakes, pales, Ac., as it is very tough and durable ; it works similarly 
 to ash, and is very good for turning. 
 
 It grows most abundantly in the Southern States ; but it is pretty generally diffused throughout 
 the whole country. It sometimes exceeds four feet in diameter and seventy feet in height. I here 
 are no less than 140 species of forest-trees indigenous to the United States which exceed thirty 
 feet in height. In France there are about thirty, and in Great Britain nearly the same number. 
 
 The locust-tree of the West Indies and Guiana is Hymenea Courbaril, (Semiri,) a tree from 60 
 to 80 feet in height, and five or six feet in diameter : the color of the wood of West Indian locust- 
 tree is light reddish-brown, with darker veins, and the main size 36 inches. The wood in its native 
 country is used for mill-rollers and cogs of wheels. Another tree, called honey locust, Gleditschia 
 triacanthus, of which the wood splits with great ease, is coarse-grained, and but little used. 
 
 Logwood, called also Campeacliy logwood, is from the bay of that name, and from Jamaica, Honduras, 
 Ac. It is scarcely used for turning, and is a dark purple-red dyewood, that is consumed in large 
 quantities : its botanical name is Hcematoxylon campechianum. 
 
 Mahogany, the Swietenia Mahogoni, is a native of the West Indies and the country round the Bay of 
 Honduras. It is said to be of rapid growth, and so large that its trunk often exceeds 40 feet in 
 length and 6 feet in diameter. This wood was first brought to London in the year 1724 ; its Span 
 ish name is Cadba. 
 
 Spanish mahogany is imported from Cuba, Jamaica, Hispaniola, St. Domingo, and some other 
 of the West India islands, and the Spanish Main, in logs from about 20 to 26 in. square, and 10 ft. 
 long. It is close-grained, hard, sometimes strongly figured, and generally of a darker color than 
 Honduras mahogany ; but its pores frequently appear as if chalk had been rubbed into them. 
 
 Honduras mahogany is imported in logs of larger size than the above, that is, from 2 to 4 ft 
 Square, and 12 to 18 ft. in length: sometimes planks have been obtained 6 or 7 ft. wide. Hon- 
 duras mahogany is generally lighter than the Spanish, and also more open and irregular in the 
 grain : many of the pieces are of a fine golden color, with showy veins and figures. The worst 
 kinds are those the most filled with gray specks, from which the Spanish mahogany (except the 
 Cuba) iso comparatively free. 
 
 Both Spanish and Honduras mahogany are supposed to be produced by the same tree, Swietenia 
 Mahogoni of botanists, but some suppose that the Honduras is the wood of a different spe- 
 cies, (V. Don, Syst. 1. p. 688 ;) but Long, in his history of Jamaica, says, “ What grows on rocky 
 grounds is of small diameter, but of closer grain, heavier weight, and more beautifully veined ; 
 what is produced in low, rich, and moist land is larger in dimensions, more light and porous, 
 and of a pale complexion. This constitutes the difference between the Jamaica wood and that 
 which is collected from the coast of Cuba and the Spanish Main ; the former is mostly found 
 on rocky eminences, the latter is cut in swampy soils near the sea-coast.” 
 
 . African mahogany, ( Swietenia senegalensis.) from Gambia, is a more recent importation ; it 
 twists much more than either of the above, and is decidedly inferior to them in all respects, except 
 hardness. It is a good wood for mangles, curriers’ tables, and other uses where a hard and cheap 
 wood of great size is required : it admits of being turned equally as well as the others. 
 
 African mahogany is the wood of Khaya senegalensis, a genus very closely allied to the Swietenia. 
 
WOODS, VARIETIES OF. 
 
 945 
 
 Mahogany shrinks but little in drying, and twists and warps less than any other wood ; on 
 which account it is used for founders’ patterns, and other works in which permanence of form is of 
 primary importance. For the same reason, and from its comparative size, abundance, soundness, 
 and beauty, it is the most useful of the furniture woods, and it holds the glue the best of ali, 
 Mahogany is also used for a variety of turned works, apart from upholstery and cabinet-work. 
 The Spanish mahogany is, in general, by far the best, although some of the Honduras nearly ap- 
 proaches it, except in hardness and weight. The African is by no means so useful or valuable as 
 either of the above, especially as it alters very much in drying. 
 
 There are two other species of Swietenia, besides the mahogany-tree, which are natives of the East 
 Indies: the one, a large tree of which the 'wood is of a dull red color, and remarkably hard ami 
 heavy ; the other is only a middle-sized tree, the wood of which is close-grained, heavy, and dur- 
 able, of a deep yellow color, and much resembles boxwood ; but neither of these species is in com- 
 mon use in this country. — Tredgold. 
 
 The first of these trees was formerly referred to Swietenia, but is now Soymida febrifuge/ ; the 
 second is probably Chloroxylon Swietenia , which is the satin-wood of India and Ceylon. A 
 third species, much admired for its light color, close grain, and being elegantly veined, is the 
 Chikrassee of the natives, and Chikrassia tabularis of botanists : the wood is much employed 
 in making furniture and cabinet-work. , The wood of the Toon-tree, Cedrela Toona, is some- 
 times called Indian Mahogany. 
 
 Maxchineel, a large tree of the West Indies and South America; the wood possesses some of the 
 general characters of mahogany, and is similarly used, but it is much less common. The wood is 
 described as being yellow-brown, beautifully clouded, and very close, hard, and durable. It is 
 said the Indians poison their arrows with its juice, and that the wood-cutters make a fire around 
 it before felling it, to cause the poisonous sap to run out, to avoid injuring their eyes. 
 
 This has been accurately described in Bancroft’s Guiana, p. 36-^1 : “ The juice of this tree is a 
 deadly poison ; it bears a little apple appearing so tempting, that many new-comers have been 
 poisoned by eating it. The tree is poisonous while green ; sleeping under it has been said to have 
 the most deadly effect. 
 
 Hippomane Mancinella is the Manchineel-tree of the West Indies. Cameraria lat folia is called 
 bastard Mancliineel. 
 
 Mangrove. Native woods of the shores of the tropics, bearing this name, and those of Mango, Mangle, 
 Maniglier, (Fr.) &c., differ very much in kind: some bear the appearance of very indifferent ash 
 and elm, others of good useful woods of the same kind, some are dark-colored, and many of them 
 have the red mahogany character. 
 
 One of the latter kind known to cabinet-makers has less of the brown and more of the red tint 
 than mahogany ; it becomes darker on exposure, but not in general as much so as mahogany. 
 This Mangrove is straight-grained, hard, and elastic, and stands better than Spanish mahogany, 
 and it is therefore preferred for straight edges and squares. 
 
 The Mangrove-tree is Rhizopliora Mangle, of which the wood is employed in making staves 
 for sugar hogsheads. Growing in the same situations with it are two trees to which the name 
 mangrove is also applied : the Conocarpus racemosa is called the white Mangrove by Sloane, 
 and Avicennia tomentosa, olive Mangrove. Coccoloba uvifera, sea-side grape, also grows in 
 the same situations, and is a large tree, of which the wood is of a reddish color. 
 
 Maple is considered to be allied to the sycamore, which is sometimes called the great maple, (Acer 
 Pseudo-platanus,) or the plane-tree. The English, or common maple, is of this kind ; its color is 
 pale yellow-brown. 
 
 The American is very beautiful, and distinguished as bird’s-eye maple and mottled maple. 
 The latter is principally used for picture-frames ; the former is full of small knots that give rise 
 to its name : the grain varies accordingly as the saw has divided the eyes transversely or longi- 
 tudinally, as pieces cut out in circular sweeps, such as chair-backs, sometimes exhibit both the 
 bird's-eye and mottled figures at different parts. Much sugar is made from this variety of maple. 
 The common maple ( Acer campestris ) is very much used for house-carpentry and furniture. 
 
 The so-called Russian maple is considered to be the wood of the birch-tree ; it is marked in a 
 manner similar to the American maple, but is unlike it, inasmuch as there are little stripes that 
 appear to connect the eyes, which in the American are quite distinct, and arise from a different 
 cause. All but the first are much used in handsome cabinet-work, and their diversities of grain 
 are very beautifully shown in turned works. 
 
 Acer campcstre is the common maple, and A. platanoides the platanus-like or Norway maple, 
 while A. pseudo-platanus is the great maple, sycamore, or mock plane-tree. A. saccharinum 
 is the sugar-maple, and its wood is often called bird’s-eye maple. A. rubrum, circinatum, 
 striatum, and eriocarpum, are other American species of which the timber is employed and 
 more or less valued. Acer oblongum, cultratum, caudatum, sterculiaceum, and v illosum, are 
 Himalayan species, of which the timbers may be employed for the same purposes. 
 
 SIaracaybo is a furniture-wood of moderate size, as hard as good mahogany, and in appearance be- 
 tween it and tulip-wood. It is sometimes called Maracay bo-cedar, but it has no resemblance to 
 the cedar, although it may grow in the vicinity of the Bay of Maracaybo. 
 
 Medlar-tree, ( Mespilus germanica :) the wood is white, soft, and being small, is not much used, ex- 
 cept for walking-sticks. 
 
 Micocoulier. See Nettle-tree. 
 
 Mora-wood. Specimens of the Mora-tree have been described by Mr. Bentham under the head Mora 
 excelsa ; the tree is 100 feet high, and abundant ; the wood is close-grained like teak, and superior 
 to oak, esteemed for ship-building, and likewise fitted for knees from the branches growing crooked ; 
 in color ,t resembles moderately red mahogany. 
 
 Vol. II. (10 
 
WOODS, VARIETIES OF. 
 
 946 
 
 Mosatahiba. See Mustaiba. 
 
 Mulberry-tree, ( Morus ,) consists of about twenty varieties, of which the yellow fustic is one that is 
 imported in considerable quantities from Rio de Janeiro. Bergeron very strongly recommends 
 the white mulberry, which he describes as similar to elm, but very close in the grain, and suitable 
 for furniture. He says the white is greatly superior to the black mulberry. 
 
 Morns nigra is the black, and Morus Alba the white mulberry ; there are several other species 
 of which the wood is esteemed for its toughness, as of Morus parvifolia in India, for hard- 
 ness and tenacity. See Fustic. 
 
 Mustaiba, from the Brazils and Rio Janeiro, is imported in logs about 1 by 10 in., also in planks; it is 
 generally of an inferior rosewood character, but harder, and is sometimes equally good ; the veins 
 are of a chestnut brown, running into black. In its grain it resembles some of the iron-woods and 
 black partridge-wood ; it has fewer resinous veins than the rosewoods. Mosatahiba, as well as 
 lignum-vitse, cocoa- wood, Ac., is used at Sheffield for the handles of glaziers’ and other knives ; some 
 of the better kinds are very good for turning, as the wood is close, sound, and heavy. 
 
 Nettle-tree, ( Celtis australis.) Micocoulier of the French, has wood that is compact, between oak and 
 box for density, and takes a high polish; it is described in the French works as a heavy, dark, 
 close wood, without bark, very durable and free from flaws. It is said to be used for flutes, and 
 for carving ; it is also called bois de Perpignan. 
 
 Nicaragua-wood, a native of South America, is imported from the bay of Nicaragua, and also from St. 
 Lucia, Rio de la Hache, Mexico, Ac., in rough groovy logs without sap, that measure from 2 to 9 
 inches through, and 2 to 3 feet long. 
 
 Another sort, from Lima, Jamaica, and Peru, called by the dyers Peachwood, apparently from 
 the color for which it is used, is shipped in logs sometimes as large as 18 inches diameter, and 6 
 feet long. Both are similar to Brazil-wood in color, and are generally too unsound for turning. 
 
 The trees yielding Nicaragua and Peach woods have not been yet ascertained, but have been 
 supposed to be species of Casa/pinia, or of Hoematoxylon, but they may be very distinct, as 
 colored woods belong to other genera. 
 
 Nutueg-wood. See Palm. 
 
 Qae, ( Quercus .) Of this valuable timber there are great varieties. Oak of good quality is more dura- 
 ble than any other wood that attains the same size ; its color is a well-known brown. Oak is a 
 most valuable wood for ship-building, carpentry, frames, and works requiring great strength or 
 exposure to the weather ; also for the staves of casks, spokes of wheels generally, and the naves 
 of wagon-wheels, for tree-nails, and numerous small works. The red varieties are inferior, and are 
 only employed for ornamental furniture. 
 
 The English oak is one of the hardest of the species; it is considerably harder than the Ameri- 
 can, called white and red oak, or than the wainscot oak from Memel, Dantzic, and Riga ; the latter, 
 which are the more interspersed with the ornamental markings or flower, from the septa or me 
 dullary rays in the wood, are the least suitable as timber. 
 
 The wainscot oak of Norway is remarkably straight, and splits easily ; so much so, that it is the 
 practice of the country to bore a small hole in the top of the tree at the beginning of the winter, 
 and to fill it with water, the expansion of which in freezing rends the tree from top to bottom. 
 
 The live oak is a fine tree, that is met with in the Southern States ; it is very different in ap- 
 pearance from the others, as the veins are small, and more evenly distributed throughout the 
 wood ; it is used in this country, along with the North American red cedar, for our finest ships ; it 
 is considered to be durable when dry, but not when exposed to wet. 
 
 “ The sea air seems essential to its existence, for it is rarely found in the forests upon the main- 
 land, and never more than 15 or 20 mile9 from the shore.” “ The live oak is commonly 40 or 50 
 feet in height, and from 1 to 2 feet in diameter, but it is sometimes much larger.” 
 
 There is also a fine evergreen oak in the Cordilleras of the Andes. 
 
 The African oak is well adapted to the construction of merchant vessels, but it is apt to sjrlinter 
 when struck by shot ; it is therefore less used for ships of war. They are all softened by steaming, 
 and are then much more easily cut or bent ; the African bends less than the others, and is the 
 darkest in color, but it has not the silver grain nor the variegated appearance of the others : it is 
 sometimes called Teak, (which see.) 
 
 Of the British oak there are two distinct species according to modern botanists. The Quercus 
 Pobur, sometimes called pedunculata, has acorns which are supported on long footstalks or 
 peduncles ; this timber is considered by some superior to that of the other species Q. sessili- 
 flora, but this probably depends on situation, as the strength and toughness of this kind, as 
 well as its durability, have been proved to be great. Dr. Lindley says its wood may be 
 known by its medullary rays or silver grain being so far apart that it cannot be rent, and this 
 gives it quite a peculiar aspect. 
 
 Quercus Ilex, the evergreen or holm oak, is common to the South of Europe ; the wood is hard, 
 heavy, and tough. Q. Suber is the cork-tree. Q. Cerris, called the Turkey oak, is common 
 in the southeast of Europe ; its timber is ornamental, being beautifully mottled, in conse- 
 quence of the abundance of its silvery grain, and is supposed to be often as good as any other ; 
 the Sardinian oak is apparently produced by it. The Wainscoat oak is supposed by some to 
 be produced by Q. Cerris. Dr. Lindley considers it to be. a variety of Q. sessilijlora, grown 
 fast in rich oak land. Q. hispanica, the Spanish oak, and Q. austriaca, the Austrian oak, are 
 found in the countries from which they are named ; and Q. MDyilops is the Valonia oak 
 abounding in Greece and Asia Minor, from which countries such large quantities of its acorns 
 are imported into England. Q. Crini/a is common in Asia Minor, yields excellent timber, and 
 is employed by the Turks in naval architecture. 
 
 The American oaks are numerous, but the timber of Quercus alba , or the white oak, comes near 
 
WOODS, VARIETIES OF. 
 
 947 
 
 est to the English oak, and is largely exported to England as 'well as to the West Indies. 
 Q. virens, the live oak, is confined to the southern of the United States, and is also found in 
 Texas ; it is said to yield the best oak in America, the timber being heavy, compact, and fine- 
 grained. 
 
 Q. tinctoria, dyers’ or black oak, is best known from its inner bark being used as a yellow dye, 
 under the name of Quercitron ; its wood is strong, but coarse. The other American oaks are 
 inferior in the quality of their timber. Besides these there are Indian and Himalayan oaks : 
 rue timber of some of the latter is excellent in quality. 
 
 The African oak, or Teak, as it is also called, is not a species of Quereus, V. Teak. 
 
 Olive-wood, principally imported from Leghorn, is the wood of the fruit-tree, (Olea europea ;) it is much 
 like box, but softer, with darker gray-colored veils. The roots have a very pretty knotted and 
 curly character ; they are much esteemed on the Continent for making embossed boxes, pressed 
 into engraved metallic moulds. 
 
 There is another wood, apparently from South America, called Olive-wood, but it does not agree 
 in color, either with the fruit or wood of the olive-tree, but is of a greenish orange, with broad 
 stripes and marks of a darker brown tint ; it is a handsome wood for turning, but not very hard. 
 
 Elmodendron glaucum is called bois d'olive, but there is no proof that it yields the olive-wood 
 alluded to, as the country from which this is imported is not distinctly known. 
 
 Omander. See Coromandel. 
 
 Orange-tree. The orange, lemon, and lime trees, (Citrus,) are evergreens that seldom exceed about 
 15 feet in height. The wood is only met with as an object of curiosity: it is of a yellow color, 
 but devoid of smell. See Apricot-tree. 
 
 The orange is Citrus Aurantium , the lemon C. Lhnonum, the lime C. Lbnetta, and the citron 
 C. Medica. 
 
 Palm-trees. Several varieties of the four or five hundred which are said to exist are imported from 
 the East and West Indies: they are known by the names palm, palmetto, palmyra, and nutmeg, 
 leopard, and porcupine wood, <fcc., from their fancied resemblances, as when they are cut horizon- 
 tally they exhibit dots like the spice, and when obliquely, the markings assimilate to the quills of 
 the porcupine. 
 
 The trunks of the palms are not considered by physiological botanists to be true wood ; they all 
 grow from within, and are always soft and spongy in the centre, but are gradually harder towards 
 the outside : they do not possess the medullary rays of the proper woods, but only the vertical 
 fibres, which are held together by a much softer substance, like pith or cement, so that the hori- 
 zontal section is always dotted, by which they may be readily distinguished from all true woods. 
 
 The Areca Catechu, or betle-nut palm, is remarkably perpendicular ; it grows to the height of 
 about 30 feet, and rarely exceeds 4 or 5 inches diameter ; it bears a small tuft of leaves, and the 
 fruit is in clusters like grapes. The betle-nut is chewed by the Indians along with quicklime, and 
 the leaf of the Piper Betle, in the manner of tobacco. The general color of the wood is a light 
 yellow-brown ; the fibres are large, hard, and only a few shades darker than the cementitious 
 portions. 
 
 The Cocos nucifera, or cocoanut palm, flourishes the best in sandy spots near the sea-beach, and 
 sometimes grows to 90 feet in height and 3 feet in diameter, but is generally less ; it is rarely 
 quite straight or perpendicular, and has broad pendent leaves from 12 to 14 feet long, in the midst 
 of which is a sort of cabbage, which, as well as the fruit, the cocoanut, is eaten ; the husk of the 
 nut supplies the material for coir-rope and matting. No part of this interesting tree is without its 
 grateful service to the Indian : the leaves are used for making baskets, mats, and the covering of 
 his dwelling ; he also obtains from this tree oil, sugar, palm-wine, and arrack ; and although the 
 upper part of the trunk is soft and stringy, the lower supplies a useful wood, the fibres of which 
 are of a chestnut brown, and several shades darker than the intermediate substance ; the wood is 
 employed for joists, troughs for water, and many purposes of general carpentry. The Asiatic So- 
 ciety has specimens marked male, 1st, 2d, 3d, 4th sorts, and the same number of female varieties ; 
 no material distinction is observable between them. 
 
 The Niepere palm is much darker than either of the preceding kinds ; the fibres are nearly black 
 and quite straight, and the cement is of a dark brown, but in other varieties with these black fibres, 
 the softer part is very light-colored, and so friable that it may be picked out -with the fingers ; at 
 the Isthmus of Darien, they use the fibres of some of the palms as nails for joinery-work. 
 
 Palmyra-wood, or that of Borassus Jlabelliformis, says Mr. Laird, is largely imported into Madras 
 and Pondicherry, from the Jaffna district at the northern part of Ceylon, for the construction of flat 
 roofs, the joists of which consist of two slabs, the third or fourth part of the tree, bolted together 
 by their flat sides so as to constitute elliptical rafters. They are covered first with flat tiles, and 
 then with a white concrete called Clvunam, consisting of shell-lime, yolks of eggs, and Jaggree, 
 (sugar,) beaten together with water in which the husks of cocoanuts have been steeped. 
 
 The prickly pole ( Cocos guianensis ) of Jamaica, tfec., a palm growing 40 feet high, and of small 
 diameter, is said to be very elastic, and fit for bows and rammers. 
 
 The smaller kinds are imported under the names of Partridge canes, (called also Chinese or 
 fishing canes,) Penang canes from the island of that name, together with some other small palms 
 which are used for walkiDg-sticks, the roots serving to form the knobs or handles The knobs of 
 these sticks exhibit irregular dots something like the scales of snakes ; these arise from the small 
 roots proceeding from the principal stem, which latter shows dotted fibres at each end of the stick, 
 and streaks along the side of the same. 
 
 The twisted palm sticks are the central stems or midribs of the leaves of the date palm; they 
 are twisted when green, and stretched with heavy weights until they are thoroughly dry : thej 
 are imported from the Neapolitan coast, but arc considered to be produced in Egypt. 
 
948 
 
 WOODS, VARIETIES OF. 
 
 The bamboos, •which like the palms are endogens, are used in India and China for almost even 
 purpose in the arts ; amongst others, in working iron and steel, as the bamboo is preferred as fuel 
 in this art : the large pieces serve as the blowing cylinders, the small as the blast-pipe, and also 
 when combined with a cocoanut-shell constitutes the hookah of the artisan. The bamboos, and 
 several of the solid canes, are used as walking-sticks, and for umbrella and parasol sticks. 
 
 The shells of the cocoanut and coquilla-nut, and the kernels of the areca or betle-nut, and those 
 of the corosos or ivory-nut, have likewise their uses in our workshops. 
 
 Palisander, a name used in Europe for rosewood. 
 
 There is considerable irregularity in the employment of this name; ii^tlie work of Bergeron a 
 kind of striped ebony is figured as hois de Palixandre ; in other French works this name is 
 considered a synonym of hois violet, and stated as a w’ood brought by the Dutch from their 
 South American colonies, and much esteemed. 
 
 Partiudge-wood is the produce of the Brazils and the West Indian Islands ; it is sent in large planks, 
 or in round and square logs, called from their tints red, brown, and black, and also sweet partridge ; 
 the wood is close, heavy, and generally straight in the grain. The colors are variously mingled, 
 and most frequently disposed in fine hair-streaks of two or three shades, which in some of the curly 
 specimens cut plankways resemble the feathers of the bird ; other varieties are called piheasant- 
 wood. The partridge-woods are very porous ; cut horizontally the annual rings appear almost as 
 two distinct layers, the one hard woody fibre, the other a much softer substance thickly interspersed 
 with pores : this circumstance gives rise to its peculiar figure, which often resembles that of the 
 palm-tree woods. 
 
 Partridge-wood was formerly employed in the Brazils for ship-building, and is also known as 
 cabbage-wood : the red-colored variety is called Angelim and Cangelim in the Brazils, and Yava 
 in Cuba. 
 
 It is now principally used for walking-sticks, umbrella and parasol sticks, and in cabinet-work 
 and turning ; the ladies have patronized it also for fans. 
 
 The partridge-wood imported from the West Indies is yielded by Heisteria coccinea. The wood 
 of several trees is no doubt included under this name. 
 
 Peachwood. See Nicaragua-wood. 
 
 Pear-tree ( Pyrus communis) is a native of Europe. The wild trees are principally used, and they 
 may be obtained from 7 to Id inches diameter. The color is a light brown, approaching that of 
 pale mahogany or cedar, generally less red than the apple-tree ; and it is esteemed a very good 
 wood for carving, as it cuts with nearly equal facility in all directions of the grain, and many of 
 the old works are cut in it. It is now much used for the engraved blocks for calico-printers, paper- 
 stainers, and pastry-cooks ; it does not stand very well, unless it is exceedingly well seasoned. 
 
 Some pieces of pear-tree much resemble lime-tree from being, in the language of the workmen, 
 “ without grain,” but the pear-tree is harder and tougher, and has a few darker streaks : they are 
 used, however, for similar purposes. 
 
 Pernambouca. See Brazil-wood. 
 
 Peruvian-wood, a fine sound wood so called, is of a rosewood character, and measures about 12 to 16 
 inches through ; it is harder, closer, and lighter in color than rosewood, with a straighter distribu- 
 tion of its dark red-brown and black veins ; it has no scent. Its true name and locality are unknown. 
 
 Pigeon-wood. See Zebra-wood. 
 
 Pines > and Firs ( Pinus ) constitute a very numerous family of cone-bearing timber-trees, that thrive the 
 best in cold countries. The woods differ somewhat in color, partly from the greater or less quantity 
 of resinous matter or turpentine contained in their pores, which gives rise to their popular distinc- 
 tions, red, yellow, and white firs or deals, and the red, yellow, and white spruce, or pitch pines, 
 and larches. They are further distinguished by the countries in which they grow, or the parts 
 from whence they are shipped, as Norway, Baltic, Memel, Riga, Dantzic, and American timber, Ac. 
 
 The general characters of the wood, and its innumerable uses besides those of ship and house 
 carpentry, are too generally known to call for any description in this place ; but those who may 
 require it will find abundant information in Tredgold’s Carpentry, pages 208 to 218. The Swiss 
 pine, imported under the name Belly-boards, are used for the sounding-boards of musical instruments 
 The larch is particularly durable, from the quantity of turpentine it contains ; it has of late been 
 considerably employed for naval architecture, as likewise the Hackmetack larch : larch is consid- 
 ered the best wood for the sleepers of railways ; its bark is also used for tanning. The American 
 pitch-pine is likewise exceedingly durable, and is much used for flooring. The white hemlock 
 contains very little turpentine, and is remarkably free from knots : it is sometimes from 2 to 3 feet 
 square, and 60 to 70 feet long, and is suitable for piling, the staves of dry casks, Ac. ; it stands 
 extremely well. 
 
 The Cowdie, Kaurie, or New Zealand Pine, or Dammar a australis, is the most magnificent of the 
 coniferous woods, although not a true pine. It is said to grow from -4 to 12 feet diameter ; one that 
 had been blown down by the wind was found to measure upwards of 1 70 feet. The Norfolk Island 
 pine, Araucaria excclsa, has enormous knots. 
 
 In Norway, when they desire to procure a hard timber with an overdose of turpentine, they riug 
 the bark of the branches just before the return of the sap ; the next year they ring the upper part 
 of the stem ; the third year the central, and lastly, the lower part near the ground. By these 
 means the sap or turpentine is progressively hindered from returning, and it very much increases 
 the solidity and durability of the timber. The roots of some of the red deals so abound in turpentine, 
 that the Scottish Highlanders, the natives of the West Indies, and of the Himalayas, use splinters 
 of them as candles. The knots of deal, especially white deal, are particularly hard ; they are 
 altogether detached from the wood in the outer planks, and often fall out when exposed in thin 
 boards. 
 
WOODS, VARIETIES OF. 
 
 949 
 
 The pines and firs being so numerous, and the timbers of many being known in commerce by such 
 a variety of names, it is difficult to ascertain the trees which yield them. 
 
 The Finns sylvestris, however, called the wild pine, or Scotch fir, yields the red deal of Riga, 
 called yellow deal in London ; Abies excelsa, or Norway spruce fir, yields white deal, Abies 
 picea, or silver-fir, has whitish wood, much used for flooring ; Larix europea is the larch commoD 
 on the Alpine districts of Germany, Switzerland, and Italy. Several other pines, as P. Pinaster , 
 Pinea, Cembra, austriaca and pyrenaica, are found in the south of Europe, but their timber is 
 less known in commerce. 
 
 The North American pines, P. strobus, or Weymouth pine, called white pine in North 
 America, and much used throughout the Northern States ; P. mitis or lutea, the yellow pine, 
 is chiefly employed in the Northern and Middle States for house and ship building ; it is con- 
 sidered next in durability to P. australis, Southern pine, called also P. palustris, and yellow 
 pine, pitch pine, and red pine in different districts : it is said to form four-fifths of the houses 
 in the Southern States, and to be preferred for naval architecture. Its timber is exported to 
 the West Indies and to Liverpool, where it is called Georgia pitch-pine. Pinus tecda, frank- 
 incense pine, called w'hite pine in Virginia ; P. rigida, Virginian or pitch-pine ; P. banksiana, 
 Hudson’s Bay or Labrador pine ; P. inops, Jersey or poor pine, and P. resinosa. The American 
 pitch-pine or red pine, called Norway pine in Canada, and yellow pine in Nova Scotia, and 
 many others, yield deals of various qualities, more or less used in different districts. 
 
 The American spruce firs are the Abies alba, nigra, and rubra, the white, black, and red 
 spruce firs; the last is sometimes called Newfoundland red pine, and employed in ship- 
 building; botli it and the black pine are exported to England; Abies canadensis, hemlock 
 spruce fir, and A. balsamea, balm of Gilead fir, are also employed, although less valued foi 
 their timber, but the American larch, Larix americana, is much esteemed. On the west coasl 
 of America some magnificent pines have been discovered, as P. Douglasii and Lambertiana 
 and others in Mexico. In the southern hemisphere the Cowdie pine or New Zealand pitch- 
 tree, Dammara australis, considered so valuable for masts, belongs to the same genus as the 
 Dammar- tree, D. Orientalis. The Himalayas abound in true pines : a splendid species is the 
 Finns Dcodara already mentioned under Cedar ; so also are Pinus excelsa, Khutrow longifolia, 
 with Abies Webbiana, Findrow, and others. 
 
 Pi-ane-tree, (the Platanus occidentalism) a buttonwood-tree, is a native of North America ; it is abun- 
 dant on the banks of the Mississippi and Ohio. This, perhaps one of the largest of the American 
 trees, is sometimes 12 ft. in diameter; it is much used in the Western States. .The color of the 
 wood resembles beech, but it is softer. The American variety is sometimes called water-beech 
 and sycamore. Plane-tree is used for musical instruments and other works requiring a clean 
 light-colored wood. 
 
 The Platanus orientalis, called also lacewood, is a native of the Levant, and other Eastern 
 countries ; it is smaller, softer, and more ornamental than the above ; the beauty of its septa gives 
 it the damasked appearance from which it is sometimes named. It is commonly used by the 
 Persians for their doors, windows, and furniture, and is suitable to ornamental cabinet-work and 
 various kinds of turnery. The first kind also has septa, but they are smaller. 
 
 The true lacewood-tree is the Daphne Lagetta. 
 
 Plum-tree, ( Prunus domestica and F. spinosa) Europe, similar in general character to pear-tree, is 
 used principally in turning. This is a handsome wood : in the endway of the grain it resembles 
 cherry-tree, but the old trees are of a more reddish-brown, with darker marks of the same color. 
 It begins to rot in small holes more generally away from, rather than in the centre of the tree, and 
 it is very wasteful on that account. 
 
 Poon-wood, or Peon-wood, of Singapore, is of a light porous texture, and light-grayish cedar color ; it is 
 used in ship-building for planks, and makes excellent spars. The Calcutta poon is preferred. 
 
 Calophyllwn inophyllum is called Poona in the peninsula of India, and C. angusti folium, Dr. 
 Roxburgh says, is a native of Penang and of countries eastward of the Bay of Beugal, and 
 that it yields the straight spars commonly called Poon, and which in those countries are used 
 for the masts of ships. 
 
 Pkixces-wood, from Jamaica, is generally sent in logs like cocoa-wood, from 4 to I in. diameter, and 4 
 to 5 ft. long ; it is a light-veined wood, something like West India satin-wood, but of a browner 
 cast ; the sapwood resembles dark birchwood. It is principally used for turning. 
 
 The Princes-wood of Jamaica, called also Spanish elm, is L'ordia Gerascanthus, but the above 
 appears to be different. 
 
 PorLAR, ( Fopulus .) The woods are soft, light, easy to work, suited to carving, common turnery, and 
 works not exposed to much wear. It is considered to be very durable when kept dry, and it does 
 not readily take fire. The bark of white poplar is almost as light as cork. 
 
 The wooden polishing-wheels of the glass-grinder are made out of horizontal slices of the entire 
 stem, about one inch thick, as from its softness it readily imbibes the polishing materials. 
 
 The wood of the Abele, or white poplar, is also commonly known as Ars ; it is extensively used 
 m Europe for toys and common turnery, and is frequently of a uniform reddish color, like red deal, 
 but with very small veins. 
 
 Populus alba is the white poplar or Abele, P. canescens the gray or common white, L\ Tremida 
 is the aspen, and P. pyramidalis or fasligiata, the Lombardy poplar. There are other species 
 in North America and the Himalayas. 
 
 Prize-wood. A large ill-defined wood, from the Brazils, apparently of the cocus-wood kind, but lighter, 
 arid generally of reddish color. 
 
 Purple-heart is mentioned by Dr. Bancroft, (see Grccuhcart ;) it is perhaps the more proper name for 
 the wood next described. 
 
950 
 
 WOODS, VARIETIES OF. 
 
 Purple-wood, or Amaranthus, from the Brazils, is imported in logs from 8 to 12 in. square and 8 te 
 10 ft. long, or in planks: its color is dark gray when first cut, but it changes rapidly, and ulti- 
 mately becomes a dark purple. 
 
 Varieties of Kingwood are sometimes called purple and violet woods: these are variegated : 
 but the true purple-wood is plain, and principally used for ramrods, and occasionally for buhl- 
 work, marquetry, and turning. A few logs of purple-wood are often found in importations ol 
 Kingwood ; it is probable also that the purple-heart is thus named occasionally. 
 
 Quassia- wood. The quassia-tree is a beautiful tall tree, of North and South America and the West 
 Indies. The wood is of a pale yellow, or light brown, and about as hard as beech ; its taste is 
 intensely bitter, but the smell is very agreeable ; the wood, bark, and fruit are all medicinal. 
 
 “ This wood is well known in the Isthmus of Darien, and is invariably carried by all the natives 
 as a ‘ contra’ against the bite of venomous snakes ; it is chewed in small slices, and the juice is 
 swallowed.” — Col. G. A. Lloyd. 
 
 Quassia amara, is a small tree ; Simaruba amara is the Mountain damson of the West Indies, 
 and Picrama excelsa, the lofty Bitter- wood. All have a similarly colored wood, which is 
 intensely bitter 
 
 Queenwood, from the Brazils, a term applied occasionally to woods of the Greenheart and Cocoa- 
 wood character. 
 
 Quince-tree, {Cydonia vulgaris.) See Apricot-tree. 
 
 Red Gumwood. See Gumwood. 
 
 Red Saunders, or Ruby-wood, an East Indian wood, the produce of Pterocarpus santalinus, is prin- 
 cipally shipped from Calcutta in logs from 2 to 10 in. diameter, generally without sap, and some- 
 times in roots and split pieces ; it is very hard and heavy ; it is very much used as a red dye- 
 wood, and often for turning. The logs are often notched at both ends, or cut with a hole as for 
 a rope, and much worn externally from being dragged along the ground ; other woods, and also 
 the ivory tusks, are sometimes perforated for the like purpose. 
 
 The wood of Adenanthera pavonia (see Coral-wood) is similar in nature, and sometimes con- 
 founded with the red saunders. 
 
 Rosetta-wood is a good sized East Indian wood, imported in logs 9 to 14 in. diameter ; it is hand- 
 somely veined ; the general color is a lively red-orange, (like the skin of a Malta orange,) with 
 darker marks, which are sometimes nearly black; ths wood is close, hard, and very beautiful 
 when first cut, but soon gets darker. 
 
 Rosewood is produced in the Brazils, the Canary Isles, the East Indies, and Africa. It is imported 
 in very large slabs, or the halves of trees which average 18 inches wide. The best is from Rio 
 de Janeiro, the second quality from Bahia, and the commonest from the East Indies: the latter 
 is called East India blackwood, although it happens to be the lightest and most red of the three ; 
 it is devoid of the powerful smell of the true rosewood, which latter Dr. Lindley considers to be 
 a species of Mimosa. The pores of the East India rosewood appear to contain less or none of 
 the resinous matter, in which the odor, like that of the flower Acacia armata, arises. Rosewood 
 contains so much gum and oil, that small splinters make excellent matches. 
 
 The colors of rosewood are from light hazel to deep purple, or nearly black : the tints are 
 sometimes abruptly contrasted, at other times striped or nearly uniform. The wood is very heavy ; 
 some specimens are close and fine in the grain, whereas others are as open as coarse mahogany, 
 or rather are more abundant in veins : the black streaks are sometimes particularly hard, and 
 very destructive to the tools. 
 
 Next to mahogany, it is the most abundant of the furniture woods; a large quantity is cut 
 into veneers for upholstery and cabinet-work, and solid pieces are used for the same purposes, 
 and for a great variety of turned articles of ordinary consumption. 
 
 In the Brazils, the ordinary rosewood is called Jacaranda Cabuna ; there is a sort which is 
 much more free from resinous pores, that is called Cabuna only : and a third variety, Jacaranda 
 Tam, is of a pale red, with a few darker veins ; it is close, hard, and very free from resinous veins ; 
 its colors more resemble those of tulip-wood. 
 
 Mr. Edwards says, that “ at the time when rosewood was first imported into England, there 
 was on the scale of Custom-house duties, ‘ Lignum Rhodium, per ton, £40,’ referring to the wood 
 from which the ‘ oil of Rhodium’ was extracted, which at that time realized a very high price. 
 The officers claimed the like duty on the furniture rosewood; it was afterwards imported as 
 Jacaranda, Palisander, and Palaxander-wood, by which names it is still called in Europe. The 
 duty was first reduced to six guineas, then in 1842 to one pound, and in 1845 the duty was en- 
 tirely removed ; the consumption has proportionately increased. It is now only known as rose- 
 wood, some logs of which have produced as much as £150, when cut into veneers.” 
 
 Rosewood is a term as generally applied as iron-wood, and to as great a variety of plants in 
 different countries, sometimes from the color and sometimes from the smell of the woods. 
 The rosewood which is imported in such large quantities from Bahia and Rio Janeiro, called 
 also Jacaranda, is so named according to Prince Maximilian, as quoted by Dr. Lindley, be- 
 cause when fresh it has a faint but agreeable smell of roses, and is produced by a Mimosa 
 in the forests of Brazil. Mr. D. Loddiges informs us it is the Mimosa Jacaranda. 
 
 The rosewood, or candle-wood, of the West Indies, is Amyris balsamifera according to 
 Browne, and is also called Sweetwood, while Amyris montan a is called Yellow candle- 
 wood, or rosewood, and also yellow saunders. Other plants to which the name is also ap- 
 plied, are Licaria guianensis of Aublet, Erythroxylurn areolatum, Colliguaya odorifsra, 
 Molina, Ac. 
 
 The rosewood of New South Wales is Trichilia r/landulosa ; that of the East Indies, if flu 
 same as what is there called Blackwood, is Dalbergia latifolia. 
 
WOODS, VARIETIES OF. 
 
 95 i 
 
 The lignum rhodium of the ancients, from which the oil of the same name and having the odor 
 of roses was prepared, has not yet been ascertained ; it has been supposed to be the Genista 
 canariensis, and by others, Convolvulus scoparius. 
 
 Ruby-wood. See Red Saunders. 
 
 Sallow ( Salix caprea) is white, with a pale-red cast, like red deal, but without the veins. The 
 wood is soft, and only used for very common works, such as children’s toys : like willow, of which 
 it is a variety, it is planed into chips, and made into bonnets. and baskets; it splits well. Se<- 
 Willow. 
 
 Sandal-wood is the produce of Santalum album, a tree having somewhat the appearance of a large 
 myrtle. The wood is extensively employed as a perfume in the funeral ceremonies of the Him 
 doos. The deeper the color, which is of a yellow brown, and the nearer the root, the better i- 
 tbe perfume. Malabar produces the finest sandal-wood ; it is also found in Ceylon and the 
 South Sea Islands. It is imported in trimmed logs from 3 to 8 and rarely 14 in. diameter ; the 
 wood is in general softer than boxwood, and easier to cut. It is used for parts of cabinets, neck- 
 laces, ornaments, and fans. The bark of the sandal-wood gives a most beautiful red or ligh* 
 claret-colored dye, but it fades almost immediately when used as a simple infusion ; in the hamb 
 of the experienced dyer it might, it is supposed, be very useful. 
 
 There are woods described in the French works as red sandal-woods. See Calembeg. 
 
 The sandal-wood tree of the Malabar coast is the Santalum album ; that of the South Sea 
 Islands is considered to be a distinct species, and has been named Santalum Freycinetianuin . 
 there is a spurious sandal-wood in the Sandwich Isles, called by the natives Nailiio , (J/yo 
 porum tenuifolium.) 
 
 Sapan-wood, or Buckum-wood, (Ccesalpinia Sapan,) is obtained from a species of the same genu- 
 that yields the Brazil-wood. It is a middle-sized tree, indigenous to Siam, Pegu, the coast of 
 Coromandel, the Eastern Islands, &c. It is imported in pieces like Brazil-wood, to which, for 
 the purposes of dyeing, it is greatly inferior ; it is generally too unsound to be useful for turning. 
 
 Satin-wood. The best variety is the West Indian, imported from St. Domingo, in square logs and 
 planks, from 9 to 20 in. wide ; the next in quality is the East Indian, shipped from Singapore 
 and Bombay in round logs from 9 to 30 in. diameter ; and the most inferior is from Hew Provi- 
 dence, in sticks, from 3J to 10 in. square ; the wood is close, not so hard as boxwood, but some- 
 what like it in color, or rather more orange ; some pieces are very beautifully mottled and 
 curled. It was much in vogue a few years back for internal decoration and furniture ; it is now 
 principally used for brushes, and somewhat for turning ; the finest kinds are cut into veneers, 
 which are then expensive; the Nassau-wood is generally used for brushes. Satin-wood, of hsiid- 
 some figure, was formerly imported in large quantities from the island of Dominica. The wood 
 has an agreeable scent, and is sometimes called yellow saunders. Bergeron mentions a “ bois 
 saline rouge? 
 
 The satin-wood of Guiana is stated by Aublet to be yielded by his Ferolia guianensis, which 
 has both white and reddish-colored wood, both satiny in appearance. The satin-wood of 
 India and Ceylon is yielded by Chloroxylon Swietenia. 
 
 Sassafras-wood is a species of laurel, ( Sassafras officinalis;) the root is used in medicine. The- 
 small wood is of a light brown, the large is darker ; both are plain, soft, and close. Sassafras- 
 wood measures from 4 to 12 in. diameter; it is sometimes chosen for cabinet-work and turning, 
 on account of its scent. 
 
 Saul, or S&l, an East Indian timber-tree, the Shorea robusta, (see 377, Dr. Wallich’s Catalogue:) 
 this wood is in very general use in India for beams, rafters, and various building purposes; Saul 
 is close-grained and heavy, of a light brown color, not so durable, but stronger and tougher than 
 teak, and is one of the best timber- trees of India. Captain Baker considers Saul to resist strains, 
 howsoever applied, better than any other Indian timber; he says the Morung Saul is the best. 
 The Sissoo appears to be the next in esteem, and then the teak, in respect to strength. See 
 Baker’s Papers. 
 
 Saunders. See Red Saunders. 
 
 Service-tree. This is a kind of thorn, and bears the service-berry, which is eaten ; it is very much 
 like English sycamore in every character as regards the wood. 
 
 Bergeron describes the service-tree as a very hard, heavy, and useful wood, of a red-brown 
 color, and well adapted to the construction of all kinds of carpenters’ tools. He says they will 
 glue slips of the service-tree upon moulding planes, the bulk of which are of oak, on account 
 of its hardness and endurance. He also speaks of a foreign service-tree, (Cormier des Isles.) 
 which is harder, but more gray in color, and more veined : these appear to be totally different 
 woods. 
 
 Sissoo (Balbergia Sissoo). is one of the most valuable timber-trees of India, and, with the Saul, is 
 more extensively employed than any other in Northwest India. The ship-builders in Bengal 
 select it for their crooked timbers aud knees ; . it is remarkably strong ; its color is a light grayish- 
 brown, with darker-colored veins. “In structure it somewhat resembles the finer species of 
 teak, but it is tougher and more elastic.” There are two kinds used respectively in Bengal and 
 Bombay; the latter is much darker in color. The Indian black rosewood ( Balbergia latifolia ) 
 is a superior species of Sissoo from the Malabar coast. 
 
 Snakewood, Letter or Speckled wood, is used at Demerara, Surinam, and along the banks of the 
 Oronoko, for the bows of the Indians. The color of the wood is red hazel, with numerous black- 
 spots and marks, which have been tortured into the resemblance of letters, or the scales of the 
 reptile ; when fine, it is very beautiful, but it is scarce in England and chiefly used for walking- 
 sticks, which are expensive ; the pieces, that are from 2 to 6 in. diameter, are said to be thf 
 produce of large trees, from three to four times those diameters, the remainder being sap. 
 
952 
 
 WOODS, VARIETIES OK 
 
 Dr. Bancroft says, “ Bourra courra, as it is called by the Indians, by the French hois da lettre. 
 and by the Dutch Letter hout, is the heart of a tree growing 30 feet in height with many branch- 
 es,” die. 
 
 “The above must not be confounded with the Snakewood of the West Indies and South 
 America, the Cecropia, of which there are three species, all furnishing trees of straight and tall 
 growth, and a wood of very light structure, presenting sometimes distinct and hollow cells. 
 The Balsas, or floats, used by the Indians of South America for fishing, &c., are very commonly 
 constructed of this wood.” 
 
 It is thought by some to be the Tapura guianensis, of Aublet. 
 
 Speckled-wood. See Snakewood. 
 
 Spanish Chestnut. See Chestnut. 
 
 Spindle-tree ( Euonymus europa) is a shrubby tree, with a yellow wood, similar to the English box- 
 wood, but straighter and softer : it is turned into bobbins and common articles. Bergeron says 
 the wood is used in France for inferior carpenters’ rules, and that its charcoal, prepared in a 
 gun-barrel or any closed vessel, is very suitable to the artist, as its mark may be readily 
 effaced. 
 
 Sycamore, the Acer pseudo-platanus, is called in Europe the great maple, and in Scotland and 
 the north of England, plane-tree ; its mean size is 32 ft. high. Sycamore is a very clean 
 wood, with a figure like the plane-tree, but much smaller ; it is softer than beech, but rather 
 disposed to brittleness. The color of young sycamore is silky white, and of the old brownish 
 white ; the wood of middle age is intermediate in color, and the strongest ; some of the pieces are 
 very handsomely mottled. It is used in furniture, piano-fortes, and harps. Sycamore may be cut 
 into very good screws, and it is used for presses, dairy utensils, (fee. See Maple. 
 
 Teakwood is the produce of the Tectona grandis, a native of the mountainous parts of the Malabar 
 coast, and of the Rajahmundry Circars, as well as of Java, Ceylon, and the Moulmein and Tenas- 
 serim coasts. 
 
 It grows quickly, straight, and lofty ; the wood is light and porous, and easily worked, but it is 
 nevertheless strong and durable ; it is soon seasoned, and being oily, does not injure iron, and 
 shrinks but little in width. Its color is light brown, and it is esteemed most valuable timber in 
 India for ship-building and house-carpentry ; it has many localities. The Malabar teak grown on 
 the western side of the Ghaut mountains is esteemed the best. Teak is considered a more brittle 
 wood than the Saul or the Sissoo. 
 
 In 25 years the teak attains the size of two feet diameter, and is considered serviceable timber 
 but it requires 100 years to arrive at maturity. There is a variety, says Dr. Roxburgh, which 
 grows on the banks of the Godavery in the Deccan, of which the wood is beautifully veined, 
 closer grained and heavier than the common teak-tree, and which is well adapted for furniture. 
 
 Some of the old trees have beautiful burrs, resembling the Amboyna, which are much 
 esteemed. 
 
 The woods in general do not very perceptibly alter in respect to length ; Teak, says Colonel 
 Lloyd, is a remarkable exception. He found the contraction in length, in the beams of a large 
 room he erected in the Mauritius, to be three-quarters of an inch in 38 feet. 
 
 The teakwood when fresh has an agreeable odor, something like rosewood, and an oil is ob- 
 tained from it. He adds, “ The finest teak now produced comes from Moulmein and other parts 
 of Burmah ; some of this timber is usually heavy and close-grained, but in purchasing large 
 quantities care must be taken that the wood has not been tapped for its oil, which is a frequent 
 custom of the natives, and renders the wood less durable.” 
 
 “ At Moulmein, so much straight timber is taken and the crooked left, that thousands of pieces 
 called ‘ shin logs,’ and admirably adapted for ship-timbers, are left. Teak contains a large quantity 
 of silicious matter, which is very destructive to the tools.” 
 
 African teak does not belong to the same genus as the Indian teak ; by some it is thought to 
 be a Euphorbiaceous plant, and by Mr. Don to be a Vitex. 
 
 Toonwood has already been mentioned under the head of Cedar, as being similar to the so-called 
 Havana cedar, the Ccdrcla odorata. The toon-tree is C. Toona ; its wood is of a reddish- 
 brown color, rather coarse-grained, but much used all over India for furniture and cabinet- 
 work. 
 
 Tulip-wood is the growth of the Brazils. The wood is trimmed and cut like Kingwood, but it is in 
 general very unsound in the centre, its color is flesh-red, with dark red streaks ; it is very hand- 
 some, but it fades. The wood, which is very wasteful and splintery, is used in turnery, Tunbridge- 
 ware manufactures, and brushes. 
 
 A wood sometimes called French tulip-wood, from its estimation in that country, appears to 
 resemble a variegated cedar : it is much straighter and softer in the grain than the above, the 
 streaks are well contrasted, the light being of an orange red ; it appears to be a very excellent 
 furniture and turnery- wood, but has no smell ; it contains abundance of gum, and is considered to 
 come from Madras, but which peninsula has no pines. 
 
 Minhatico. The Portuguese name for several yellow and yellow-brown woods. See Canary-wood, 
 
 Violet-wood. See Kingwood. 
 
 Vjxewood. See Apricot-tree. 
 
 Walnut. The Royal or Common "Walnut (Jv.gl.ans regia ) is a native of Persia and the north of 
 China. Walnut was formerly much used in England before the introduction of mahogany. The 
 heart-wood is of a grayish brown, with black-brown pores, and often much veined with darker 
 shades of the same color ; the sap-wood is grayish white. Some of the handsome veneers are 
 now used for furniture, but the principal consumption is for gun-stocks, the prices of which in the 
 rough vary from a few pence to one and two guineas each, according to quality. An inferior 
 
WOODS, VARIETIES OF. 
 
 953 
 
 kind of walnut is very much used in France for furniture, frames of machines, <fec. ; it is less 
 brown than the line sort. 
 
 The Black Virginian Walnut ( Juglans nigra ) is found from Pennsylvania to Florida. It is 
 a large tree, has a fine grain, is beautifully veined, and is the most valuable of the American 
 kinds for furniture. 
 
 The White Walnut is the Hickory, which see. 
 
 Willow. There are many varieties of the willow, ( Salix .) It is perhaps the softest and lightest of 
 our woods. Its color is tolerably white, inclining to yellowish-gray ; it is planed into chips for 
 hat-boxes, baskets, and wove bonnets ; it has been attempted to be used in the manufacture of 
 paper. The small branches of willow are used for hoops for tubs, the large wood for cricket- 
 bats. From the facility with which it is turned, it is in demand for boxes for druggists and per- 
 fumers, which are otherwise made of small birchwood. 
 
 The wood of the willow is described by Mr. Loudon as soft, smooth, and light ; the wood of 
 the larger species, as Salix alaba and Russelliana, is sawn into boards for flooring. The red- 
 wood willow, S. fragiiis, is said to produce timber superior to any other species : it is used 
 for building light and swift-sailing vessels ; S. Russelliana, being closely allied to S. fragiiis, 
 is probably allied to it in properties. The wood of S. caprea is heavier than that of any 
 other species. Hats are manufactured in France from strips of the wood S. alba. 
 Yacca-wood, or Yacher, from Jamaica, is sent in short crooked pieces like roots, from 4 to 12 in. thick. 
 The wood is pale grown, with streaks of hazel brown ; it is principally used for ornamental 
 cabinet and marquetry work, and turning ; some pieces are very handsome. 
 
 Yellow-wood. There is a fine East India wood thus called ; it appears to be larger and straighter 
 than boxwood, but not so close-grained. 
 
 This is probably a Nauclea. The wood of Nauclea cordifolia, according to Dr. Roxburgh, is 
 exceedingly beautiful in color, like boxwood, but much lighter, and at the same time very 
 close-grained. It is used by the inhabitants of Northern India to make combs of. 
 
 Yew. The yew-tree is common in Spain, Italy, and England. The tree is not large, and the wood is 
 of a pale yellow-red color, handsomely striped, and often dotted like Amboyna. It has been 
 long famed for the construction of bows, and is still so employed, although the undivided sway it 
 held in the days of Robin Hood has ceased. The English species ( Taxus baccata ) is esteemed a 
 hard, tough, and durable wood : it is a common saying amongst the inhabitants of the New 
 Forest in Hampshire, that a post of yew will outlive a post of iron ; it would appear the yew- 
 tree lives to a great age, as some of those in Norbury Park are said to have been recorded in 
 Domesday Book. The yew-tree is used for making chairs, handles, archery-bows and walking- 
 sticks. Some of the older wood is of a darker color, more resembling pale walnut-tree, and very 
 beautifully marked ; the finer pieces are reserved for cabinet-work, and it is a clean wood for 
 turning. The Irish yew is preferred for bows. 
 
 The burrs of the yew-trees are exceedingly beautiful, and although larger in figure, they some- 
 times almost equal the Iviabooca. 
 
 The American yew, Taxus canadensis, is supposed to be only a variety of T. baccata; the 
 Himalayan species are closely allied to this and to T. nucifera. 
 
 Zanie, or Young Fustic, from the Mediterranean, is a species of sumach, (Rhus Cotinus.) It is small, 
 and of a golden yellow, with two-thirds sap ; it is only used for dyeing, and is quite distinct from 
 the Morus tinctoria, or old fustic. 
 
 Speaking of this tree, Dr. Bancroft says : “ A distinction was improperly created at least 130 
 years ago, (now 180,) calling that of the Venice sumach Young Fustic, (as being manifestly the 
 wood of a small shrub,) and that of Morus tinctoria, (which is always importe.d in the form of 
 large logs or blocks,) Old Fustic.” — Bancroft's Phil, of Colors, v. i. p. 413. 
 
 The Zante is also called Chloroxylon ; its modern Greek name is Imppore. 
 
 Zebra-wood is the produce of the Brazils and Rio Janeiro ; it is sent in logs and planks, as large as 
 twenty-four inches. The color is orange-brown, and dark-brown variously mixed, generally in 
 straight stripes ; it is suitable to cabinet-work and turnery, as it is very handsome. A wood 
 from New South Wales bearing some resemblance to the above is sometimes called by the same 
 name, as are also some other woods in which the stripes are of a distinct and decided character. 
 
 The zebra-wood is considered by upholsterers to be intermediate in general appearance be- 
 tween mahogany and rosewood, so as to form a pleasing contrast with either of them. The 
 Portuguese name for the zebra-wood appears from Mr. G. Loddiges’ collection to be Burapinima, 
 
 and from Mr. 's Goncalo do para : No. 53, of the last group, Casco do tartarua, is like Zebra, 
 
 but heavier, more handsome, and of a rich hazel-brown, with black wavy streaks. The pigeon- 
 woods are usually lighter, and of more yellow-browns. 
 
 Zebra-wood is also called Pigeon-wood ; one kind of Pigeon-wood in Jamaica is Gucttarda 
 speciosa. 
 
 Memoir on the preservation of woods. — A paper bearing this title was lately read before the French 
 -ieademy of Sciences, by its author, Dr. Boucherie, and as an appropriate sequel to the foregoing pages 
 ipon the woods, we append a synopsis of the numerous experiments referred to. 
 
 He contrasts the increasing consumption and the rapid decay of timber, with its slow rate of produc. 
 tion, which make it necessary to economize its employment. He adverts to the many projects for its 
 preservation, enumerated by Mr. John Knowles, and the methods subsequently proposed, to many of 
 which he objects from their uselessness ; to others from the slow and superficial manner in which 
 timbers part with their contained fluds, or absorb new ones by simple immersion, (circumstances 
 long since proved by Duhamel ;) and t > all from their expense, which is of course the ultimate test of 
 general application. 
 
954 
 
 WOODS, VARIETIES OF 
 
 Dr. Boucherie argues, that all the changes in woods are attributable to the soluble parts they contain, 
 which either give rise to fermentation or decay, or serve as food for the worms that so rapidly penetrate 
 even the hardest woods. As the results of analyses, he says that sound timbers contain from three to 
 seven per cent, of soluble matters, and the decayed and worm-eaten rarely two, commonly less than 
 one, per cent. ; he therefore concludes that “ since the soluble matters of the wood 'were the causes of 
 the changes it undergoes, it is necessary to its preservation, either to abstract the soluble parts in any 
 way, or to render them insoluble by introducing substances which should render them infermentable 
 or inalimentary which he considers may be done by many of the metallic salts and earthy chlorides. 
 
 Dr. Boucherie shows, by parallel experiments upon “vegetable matters very susceptible of decom- 
 position, as flour, the pulps of carrot and beet-root, the melon, &c., (which only differ from wood, of 
 which they possess the origin and constitution, by the greater proportion of soluble matter which they 
 contain,”) that in the natural states they rapidly alter, but are preserved by the pyrolignite of iron, 
 (pyrolignite brut de fer,) a cheaper material than the corrosive sublimate commonly used, and one very 
 desirable in several respects. He presumed that by immersing the end of a tree immediately after it 
 was felled into a liquid, the vital energies not having ceased, the tree would then absorb such fluid 
 through all its pores, by a process which he calls aspiration ; and in this fortunate surmise he was en- 
 tirely successful. This led step by step to numerous practical results, which their inventor enumerates 
 as follows, and describes in separate chapters. 
 
 1st. “ For protecting the woods from the dry or wet rot.” 
 
 2d. “ For augmenting their hardness.” 
 
 3d. “For preserving and developing their flexibility and their elasticity.” 
 
 4th. “ For rendering impossible the changes of form (jcu) they undergo, and the splits ( disjonctions ) 
 which take place when they are brought into use, or are submitted to atmospheric changes.” 
 
 5th. “For greatly reducing their inflammability and combustibility.” 
 
 6th. “ For giving them various and lasting colors and odors.” 
 
 We shall endeavor to convey a general notion of the methods in the same order. 
 
 1. Durability. He took a poplar tree measuring 28 mitres in height and 40 centimetres diameter, 
 simply divided from its root with its branches and leaves undisturbed, and immersed it erect to the 
 depth of 20 centimetres in a vessel containing pyrolignite of iron ; in six days it was entirely impreg- 
 nated even to the leaves, and had absorbed the large quantity of three hectolitres. This method re- 
 quired powerful lifting apparatus, and a support for the tree to lean against, and hence was objectionable. 
 
 He repeatedly operated upon trees lying on the ground, by attaching to their bases water-proof bags 
 containing the liquid : the experiments were varied in many ways ; sometimes portions of the branches 
 were lopped oft) but the crown or tuft was always left upon the principal stem ; at other times the 
 aspiration was effected by boring detached holes near the earth supplied with different fluids, which 
 gave rise to all kinds of diversities in the result ; and other trees were pierced entirely through, and a 
 horizontal cut extending to within an inch or so of each side was made with a thick saw, leaving only 
 sufficient wood for the support of the trees. 
 
 For fear of losing the trees upon which he had the opportunity of experimenting, the process was 
 not deferred beyond 24, 36, or 48 hours after they were felled, as the vigor of the absorption was found 
 to abate rapidly after the first day, and that at about the tenth day it was scarcely perceptible : it was 
 also found the aspiration entirely failed in dead wood, whether occurring at the heart of old trees, or at 
 parts of others from any accidental interruption of the flow of the sap during the growth ; and also that 
 resinous trees absorbed the fluids less rapidly than others. 
 
 Observations were also made of the quantities of the liquids taken up ; these fluids, when of a neu- 
 tral kind, as the chloride of soda, often equalled in bulk that of the wood itself, without causing any 
 addition to its weight ; the acid and alkaline fluids were less abundantly absorbed, apparently from 
 contracting the vessels by their astringent action. It is stated that the pyrolignite of iron effected the 
 preservation of the substance when equal to less than a fiftieth of the weight of the green wood. These 
 points are all separately treated in the original paper. 
 
 2. The hardness of the wood was considered by various workmen to be more than doubled by the 
 action of the pyrolignite. 
 
 3. The flexibility (due to a certain presence of moisture) was increased in a remarkable manner by 
 the chloride of lime and other deliquescent salts, the degree of elasticity depending upon their greater 
 or less concentration. As a cheap substitute for the above, the stagnant water of salt marshes was 
 adopted, with a fifth of the pyrolignite, for the greater certainty of preservation. Pieces of prepared 
 deal, 3 millimetres thick and 60 centimetres long, were capable of being twisted and bent in all direc- 
 tions, as into screws, also into three circular coils; the wood immediately regained its figure when re- 
 leased ; this condition lasted eighteen months, that is, until the time his paper was read. 
 
 4. The warping and splitting, principally due to the continual effect of the atmosphere in abstracting 
 and restoring the moisture, was stayed by impregnating the wood with a weak infusion of the chloride, 
 so as always to retain it to a certain degree moist ; one-fifth of pyrolignite was also added in this case. 
 The seasoning of the wood was also considered to be expedited by the process, and which was not 
 found to interfere with the ordinary use of oil-paint, <fcc. Large boards of the prepared wood, some of 
 which were painted on one or both sides, and similar boards of unprepared wood, were compared ; at the 
 end of twelve months, the former were perfect as to form, the latter were warped and twisted as usual. 
 
 5. The inflammability and combustibility of the woods were also prevented by the earthy chlorides, 
 which fuse on their surfaces by the application of heat, and render them difficult of ignition. Twc 
 similar cabins were built of prepared and of ordinary wood respectively, and similar fires were lighted 
 in each ; the latter was entirely burned, the other was barely blackened. 
 
 6. In respect to colors infused by the aspiratory process, the vegetable colors were found to answei 
 less perfectly than the mineral, and the latter succeeded best when the color was introduced at two 
 processes, so that the chemical change (that of ordinary dyeing) occurred in the pores of the wood 
 
WOOD STEAM CARBONIZING MACHINE. 
 
 95 . 
 
 itself. Odorous matters, required to be infused in weak alcoholic solutions, or essential oils, they were 
 considered to be equally durable with those supplied by the hand of nature ; and resins similarly intro- 
 duced were found to increase amazingly the inflammability of the woods, and to render them imper 
 vious to water. 
 
 On the whole, the method is considered to promise the means of working almost any desired change 
 in the constitution and properties of woods, when the fluids are presented to them before the vitality 
 of the tree has ceased. It is true we have as yet only two years’ trial of these experiments, but they 
 have been scientifically deduced, and their inventor is still engaged in prosecuting them. It is to be 
 hoped, and also expected, that these interesting and flattering promises of success will be realized, and 
 even extended, when tried by that most severe of all tests, time.* 
 
 For the preceding article on Woods, we acknowledge our indebtedness to Holtzapffel’s Turning and 
 Mechanical Manipulation, a work we conceive of great merit. 
 
 WOOD STEAM CARBONIZING MACHINE. Description of an apparatus for carbonizing wood 
 by means of heated steam. By M. Violette. It is well known that the nature of the product of the 
 carbonization of wood, in a close vessel, varies according to the temperature : for instance, a very great 
 heat produces a black charcoal, deprived of the greater part of its volatile hydrogenated parts ; whilst 
 a more moderate heat gives a red charcoal, retaining more of the properties of wood, and still charged 
 with volatile principles. It is this latter quality of charcoal which produces the best gunpowder; and 
 it is therefore important to discover the best means of preparing it. With this object in view, M. 
 Violette has, by experiment, determined the limits within which a red charcoal may be obtained : that 
 is to say, a product which is not wood, and yet is not perfect charcoal. To effect this object he employs 
 a bath of metal, fusible at 160°, composed of one part bismuth, 4 parts of lead, and 3J parts of tin. 
 This metal he keeps in fusion in a deep glass vessel, suspended over a Carcel lamp. A thermometer, 
 graduated at 350°, is immersed in this bath to show the temperature. The pieces of wood to be experi- 
 mented upon are fastened to the ends of platina wires, and put into glass tubes, closed at one end, and 
 immersed in the metallic bath. By this arrangement the wood is maintained at the temperature indi- 
 cated by the thermometer, and sufficiently protected from contact with the atmosphere. The wood 
 may be withdrawn for inspection, when required, by means of the platina wires. A suitable and un- 
 varied temperature may be maintained by raising or lowering the wick of the lamp at the beginning of 
 the operation. The wood exposed in this apparatus during an hour to a temperature of from 200° to 
 250°, does not become converted into charcoal; at the end of two hours, at the same temperature, it is 
 converted into red charcoal, its surface being properly carbonized, but its interior being still wood ; at 
 the end of three hours it is converted into a hard red charcoal, brittle, and burning with flame, but inca- 
 pable of extending its combustion ; if submitted for an hour to a heat of 300' a very good red charcoal 
 is obtained, of sufficient hardness, but easily pulverizable ; on the prolongation of the experiment 
 to two hours a more perfect charcoal is obtained, which burns with flame; and lastly 7 , at a temperature 
 of 350°, and at the end of half an hour, a charcoal is obtained which is black, friable, and easily 
 pounded. 
 
 The first experiments were made with a small apparatus, capable of containing about 2 lbs. of wood ; 
 and, independently of the superior quality of the powder manufactured with the charcoal thus obtained, 
 it was found that the product was augmented to as much as 42 per cent, of the weight of the wood. 
 
 The apparatus now employed for this purpose is shown below, Fig. 3953 being a longitudinal vertical 
 section, and Fig. 3954 a transverse section in the line a b of Fig. 3953. It consists of two hollow con- 
 3954. 3953. 
 
 centric iron cylinders, H and II ; in the inner one (II) of which the wood to be carbonized is placed. 
 C is a coil of steam pipe, communicating at one end with a steam-boiler, and at the other with the 
 outer cylinder H. A is the fire place, (which may be fed with wood or coke, or some other suitable 
 fuel,) wherein the steam-pipe is heated to any required degree of temperature. The cylinder H is 
 closed by a wrouglit-iron cover 1, and the apparatus is provided with two outside cast-iron doors FF, 
 by which it is protected from the cooling action of the atmosphere. Lisa pipe for letting off the steam 
 and the products of the distillation of the wood from the cylinder K. G is the flue, for the escape of 
 the smoke from the fireplace A. The whole apparatus is surrounded by brickwork or masonry, N. 
 
 * In France, Ur. Boucherie has relinquished his brevet , and thrown the process open to the public in consideration of a 
 national reward ; and immense preparations are being there made, by the Minister of Marine, for the employment of the 
 preservative process for the French navy. In England Dr. Boucherie and Company have obtained two patents, and Mr. 
 Puddock, their agent, has specimens of pine, plane-tree, &c..' variously prepared and colored, with the pyrolignite of iron, 
 the prussiate of iron, the prussiate of copper, and various other metallic salts, &c. 
 
956 
 
 WRENCH, CYLINDER. 
 
 The wood to be carbonized is first placed in a cylinder, made either of wire work or perforated metal, 
 which is introduced into the cylinder K; by this arrangement, should the charcoal become ignited on 
 being taken out, the flame will be prevented from spreading. The charge in this apparatus weighs 
 from 30 to 40 lbs. 
 
 Mode of operation. — The first thing to be done is to get up the steam, until the manometer indicates 
 one atmosphere ; the fireplace for heating the steam-pipe is then to be lighted, and in about a quartet 
 of an hour the doors may be opened, and the perforated cylinder containing the wood introduced into 
 the cylinder Iv, which is then closed by means of the cover I ; a luting of clay being made round the 
 edge thereof, and a screw ni applied to fasten the cover in its place, the outer doprs may then be 
 closed. After the lapse of ten minutes, when the luting has become sufficiently dried, the induction 
 steam-cock is opened, and the steam rushes into the steam-pipe C, where it becomes heated; from 
 thence it passes into the outer cylinder H, and into the inner cylinder K at its open end, where it grad- 
 ually insinuates itself into the pores of the wood, acting, by its great heat, in such a manner as to car- 
 bonize it, and finally makes its escape through the pipe L, carrying with it the gases evolved from the 
 wood. In order to keep the fire at a certain temperature, there is a small glazed opening at a, through 
 which the workman can see that the flame acts properly upon the steam-pipe. After some time, a ther- 
 mometer, (specially constructed for the purpose,) on being introduced into the cylinder K, shows that 
 the temperature has reached such a height as to melt tin ; and the steam which escapes shows, by its 
 color and odor, that it is mixed with the first products of distillation of the wood, and that the carboni- 
 zation has commenced. The smoke or vapor thickens, and takes successively various aspects, which 
 are certain signs of the progress of the operation. After about two hours from the time the distillation 
 was first apparent, the smoke shows that the operation is finished. The attendant then proceeds to 
 discharge the charcoal ; and for this purpose two other attendants are ready with what is called the 
 extinguisher , a large iron cylinder, about three feet in diameter, and about six feet in length, to receive 
 the charcoal. The chief attendant then shuts off the steam, opens the doors F, turns the screw m, lays 
 hold, by means of wooden handles, of the respective ends of the cross-bar J, which keeps the disk in its 
 place, detaches it, and plunges it into a vessel full of water close by ; then, by means of the same wooden 
 handles, he takes hold of the disk, and twisting it round, so as to break the luting, detaches it, and plunges 
 it also into the vessel of water. The attendants holding the extinguisher put it in a horizontal position 
 in front of the cylinder K, so as to close the orifice. The chief attendant then pushes a long rod through 
 the pipe L, so ns to push the cylinder containing the charcoal into the extinguishing cylinder, which is 
 then quickly placed on the ground, and the hydraulic joint with which it is provided is filled with 
 water. The operation is then completed. 
 
 The inventor has observed that there are no traces of tar in the apparatus, as it is all driven off by 
 the steam. The charcoal obtained is of very fine quality, and varies according to the temperature ; 
 that is to say, is red or black, according to the degree of heat and the length of time during which it has 
 been maintained. The former is suitable for manufacturing the finer sorts of powder for sporting pur 
 poses, and the latter, inferior powder, for blasting mines, &c. 
 
 The apparatus above described has been in operation more than a year, and has produced 5000 lbs. 
 of superior charcoal, and is now in very good condition. 
 
 Various modifications may be made in this apparatus without in any manner altering the main fea- 
 ture of the invention ; for instance, the inventor jaroposes, in some cases, to use an apparatus containing 
 three carbonizing cylinders, one of which shall not be supplied with steam, but merely serve to dry the 
 wood, and prepare it for either of the other cylinders, on either side of the steam-pipe ; this arrange- 
 ment has the effect of rendering the operation continuous. 
 
 WRENCH, CYLINDER. Invented by S. Merrick, of Springfield, Massachusetts, and patented 
 January 2, 1849. 
 
 This wrench is designed for grasping and turn- 
 ing round bolts, nuts, gas and water pipes, and 
 other cylindrical substances. 
 
 By reference to the accompanying drawings, 
 its construction and operation will be readily 
 understood. 
 
 Fig. 3955 is a side elevation ; Fig. 3956 a cen- 
 tral vertical section. The same letters refer to 
 like parts in each figure. A, main bar ; B, nut, 
 fitted to a screw, cut on the two opposite edges 
 of the main bar ; C, slide, made to move easily 
 upon the main bar, and connected with the nut 
 by a collar on the end of the nut and a groove underneath the end of the slide; D, tightening lever, 
 attached to slide C by a joint, as seen at H ; E, spring for the purpose of pressing the lever D upon 
 the main bar; F, handle. The end of the lever D is made circular, the centre of which circle is shown 
 at G, for the purpose of pressing more firmly against the cylinder I, as the end of the lever is forced 
 down towards the main bar. The circular end of the lever is also indented or roughened that it may 
 not slip on the cylinder I. H, joint of the lever D and slide C ; I, the cylindrical substance to be turned. 
 
 To operate the wrench, it is placed upon the cylinder to be turned, as seen in Fig. 3955, and the 
 indented eud of the lever D is brought in contact with it by means of the nut B. The handle is then 
 moved backwards, and the lever advanced at the same time, until the end of the lever is somewhat 
 raised from the main bar ; the handle is then carried forward in the direction shown by the arrow, which 
 causes the lever to take firm hold of the cylinder and carry it around in the same direction ; and by 
 reversing the motion of the handle, the cylinder is instantly released for a new hold. It will be ob- 
 vious that the wrench can be readily adapted to any size of cylinder within its compass, and will thus 
 supply the place of a pair of tongs (the only tool in use for the same purpose previous t>e *his inven- 
 
 3955. 
 
ZINC. 
 
 1)57 
 
 tion) for each particular size of cylinder. It also possesses the advantage of being worked with cna 
 hand after being set to the particular size required. 
 
 WRENCH, SCREW. Invented by S. Merkjck, of Springfield, Massachusetts, and patented Au- 
 gust 17, 1835 ; patent extended May 14, 1849. 
 
 In the drawings, Fig. 3957 denotes a side ele- 
 vation ; Fig. 3958, a vertical central section. 
 
 The same letters refer to like parts in each 
 figure. 
 
 A is the main bar ; B, the nut fitted to a 
 screw, cut on the two opposite edges of the 
 main bar ; C, a strap , which passes around in a 
 groove formed in the nut B, and is riveted to 
 the end of the slide-jaw D. The collar on the 
 end of the nut B takes into a corresponding 
 groove in the slide D ; E, the end of the main 
 bar, which forms the stationary jaw of the 
 wrench ; F, the handle. The nut is made to 
 move freely in the strap C, and, by turning it to 
 the right or left, the slide D is moved to any desired point on the main bar. 
 
 The principal advantages possessed by this wrench are, its simplicity of construction and consequent 
 cheapness— its compactness, durability, and strength ; the size of the main bar being duly proportioned 
 to the power applied, as will be seen in the figure. 
 
 3957. 
 
 ZINC, composition and use of. Zinc or Spelter has a crystalline texture, is brittle at ordinary tem- 
 peratures, and of a bluish-white color : at 300°, it is both malleable and ductile, and at a white heat 
 it is converted into vapor. When pure zinc is exposed to air and moisture, it acquires a dull color from 
 partial oxydizement ; and great electric action takes place when it is in contact with copper, and the 
 zinc decays in consequence. Its specific gravity is 7", and it has a great attraction for oxygen; the 
 weight of a cubic foot is 439^ pounds. 
 
 Oxide of zinc is obtained by intensely heating the metal exposed to air ; it takes fire at a red heat, 
 if the air is freely admitted, burning with a very bright flame. 
 
 Zinc 1 32 80 
 
 Oxygen J_ _8 20 
 
 1 40 100 
 
 Sulpliuret of zinc ( blende ) is found native, and is a brittle, soft metal, of a brown and black color ; its 
 primitive form is a rhomboidal dodecahedron, and it is a most abundant mineral. The pure metal is 
 obtained from it by roasting the oar, and afterwards distilling it when mixed with charcoal. 
 
 Zinc 1 32 66'5 
 
 Sulphur 1 16 33o 
 
 T" 48" 100-0 
 
 Carbonate of zinc, ( calamine .■) when found crystallized, its primitive form is an obtuse rhomboid. 
 
 Oxide of zinc 1 40 64'5 
 
 Carbonic acid 1 22 35 5 
 
 T 62 100-0 
 
 Zinc is obtained from the sulpliuret and carbonate ; the ore when broken is submitted to a dull red 
 heat in a reverberatory furnace, when the carbonic acid is driven off from the calamine, and the sul- 
 phur from the blende : it is then mixed with one-eighth of its weight of powdered charcoal, being first 
 ground and thoroughly washed, and distilled by the application of a red heat ; the metal being put 
 into earthen pots with iron tubes cemented into the lower parts, dipping into water, where it is collected, 
 and afterwards cast into cakes. A bar of zinc 12 inches long and 1 inch square, weighing 3'05 pounds, 
 expands in length at one degree of heat , and melts at 648° ; it will bear, without permanent 
 alteration, a pressure on a square inch of 5700 pounds. 
 
 Zinc is used for the preservation of iron, by electro-deposition. The iron is first rendered perfectly 
 clean and free from oxide, by placing it in a bath of heated sulphuric acid and water ; then in a cold 
 solution of sulphate of zinc. The positive pole of a galvanic battery is attached to a zinc plate, and 
 the negative to the iron to be covered ; the pure metal is deposited, and the zinc and iron are amal- 
 gamated. Wooden troughs are employed for the process, and iron plates so covered are extensively 
 used for roofing, and do not after many months exhibit any signs of decay. The iron being coated with 
 zinc in a cold solution Joes not in any way change its condition ; but when the zincing of iron is per- 
 formed by steepmg it in a bath of melted zinc, a combination takes place between the two metals, and 
 a brittle alloy is the consequence, the iron losing all its tenacity. 
 
 Tin is usually prepared from the native oxide its oxygen being removed by charcoal: the purer 
 kinds are called grain tin, and the others block tin. The common ores are known under the name of 
 mine tin, and furnish a less pure metal than the stream tin. Tin has a silvery -white color; its specific 
 gravity is 7'3, and the air and moisture have little effect upon it: it melts at 442°, and is converted 
 into a white oxide by exposure to heat and air. 
 
 The specific gravity of the native peroxide of tin is 7‘, and its primitive crystal an obtuse octohedron 
 
 Protoxide of tin : specific gravity 6'6 : 
 
 Tin 1 58 87-S 
 
 Oxygen 1 8 12 '2 
 
 1 66 10U-0 
 
9£»S 
 
 ZINC 
 
 Bmilphuret of tin ( Auruin musivum, Mosaic gold ) is a mixture formed by heating peroxide of tin 
 which contains two of oxygen and one of tin, with its weight of sulphur. Bisulphuret of tin is also 
 formed by decomposing perchloride of tin by sulphuretted hydrogen ; it is quite insoluble in the acids, 
 except nitro-muriatic ; it forms the bronze powder used by paper-stainers. 
 
 Tin 1 58 64-4 
 
 Sulphur 2 82 35 6 
 
 1 90 lUO'O 
 
 The weight of a cubic foot of cast tin is 455'7 pounds, and the weight of a bar 12 inches long and an 
 inch square is 3-165 pounds ; it expands, according to Smeaton, at one degree of heat and melts 
 
 at 442°. It will bear on a square inch 2880 pounds without any permanent alteration” and an exten- 
 sion of length of ^-1-^. Compared with cast-iron, its strength is 0182 times, and its extensibility 075 
 times, and its stiffness 0’25 times, cast-iron being considered as unity. 
 
 Zinc white , a carbonate of zinc, which is destined to supersede the white-lead as a paint. It is 
 equally durable with lead as a color, and docs not turn yellow as does lead. It is also free from the 
 poisonous qualities possessed by preparations of lead which render its effects upon the workmen who 
 use it so disastrous. 
 
 Brooman s improvements in the manufacture of zinc . — The general object of this invention is to do 
 away with the troublesome and expensive processes of assorting, pounding, and crushing, now ordinarily 
 followed in order to the extraction of zinc from its ores ; and this is effected by a method of direct reduc- 
 tion. We extract the following description of the apparatus employed, and of the peculiar processes 
 followed in connection therewith, from the patentee’s specification : 
 
 Fig. 3959 is a vertical section of the apparatus on the line A D of Fig. 3960, which is a horizontal 
 section on the (dotted) line A, B, C, D of Fig. 3959. C is the hearth of the furnace ; F, F, F are the 
 tuyeres, which are three in number; H is the shoot; U the chamber of the furnace. So far the parts 
 of the structure are very similar to those of a small blast-furnace. At IK the upper part of the cham- 
 ber U is suddenly contracted, so as to form a neck Y, or narrow passage, between the upper and lower 
 parts of the furnace. The charge, as it falls through this neck, leaves, necessarily, a vacant annular 
 space at x x, between it and the sides of the furnace, where the volatilizable matters may collect. F F 
 are four rectangular passages, formed of cast or sheet iron, which lead off at right angles, and in an 
 
 inclined direction, from the annular space xx, and each passage is encased for a certain distance within 
 a chamber G, through which cold water is kept continually circulating, flowing in from the tube P, Q, R, 
 and escaping through the pipe S S. At the lower end of each of the rectangular passages there is a 
 tubular passage A 1 , by which the uncondensed gases of the furnace are carried off to different points, 
 to be employed for heating purposes, as hereafter explained ; and each passage is provided at its lower 
 end with a sliding door A 2 which may be closed or opened as required. W is a lid or cover by which 
 the furnace is closed at top, and which fits into a groove made for it, so that there may be no escape of 
 the gases at that part. All the interior parts of the furnace are formed of fire-brick, with an outer 
 wall or casing V 1 , which may be made of ordinary brick ; and between the outer and inner walls there 
 is left a space Z Z, which is filled with some substance which is a bad conductor of heat. H H are 
 strengthening plates of cast-iron, which are inserted into the lower brick-work V 1 , immediately over 
 the tuy£re openings E 1 E 1 . L 1 are cast-iron frames, which carry the passages F F and cold- water 
 chamber G. 
 
 The mode of operating w 7 ith the apparatus is as follDws : — After (he furnace has been built, it is left 
 
ZINC. 
 
 959 
 
 to dry; then a fire is kindled on the hearth, and kept up for about three weeks by supplies of fuel (by 
 preference coke) introduced through the throat. The furnace being in this manner filled with incan- 
 descent fuel, a small charge of quicklime is thrown in. As soon as this charge has descended as far 
 down as the tuyhres, a mixture of ore, flux, and fuel is fed into the furnace, the top of the furnace 
 closed, and a moderate blast of atmospheric air applied by means of a blowing machine. 
 
 Tlie fuel, the flux, and the ore are in such proportions to one another that the whole of the zinc con- 
 tained in the ore shall be reduced, and then volatilized, while all the foreign matters shall form with the 
 flux a residual slag of more or less fluidity when in the heated state. The fuel employed may be either 
 charcoal, or coke, or common coal, or anthracite, or turf, taking care always that it is of a sufficiently 
 hard nature to resist the incumbent pressure of the charge in the furnace. 
 
 The quantity of fuel employed should be greater at the' commencement than during the subsequent 
 stages, and should in all cases be sufficient not only for the complete reduction of the zinc, but also to 
 leave so considerable an excess that when it arrives directly before the tuyeres, the combustion of the 
 fuel shall not give rise to any gaseous oxidating product ; such, for example, as carbonic acid. The flux 
 (the selection of which, as well as that of the fuel, depends on the quality of the ore) must be used in 
 such a state as not to produce any oxidating matter during the formation of the slag. For this reason, 
 when the nature of the ore requires the employment of lime as a flux, the lsme should be used in a 
 caustic state, and not as a carbonate ; and for the same reason it is advisable to use a blast of dry air, 
 that is to say, air deprived of aqueous vapor. The products of the furnace are, in the first place, the 
 gases arising from the combustion of the fuel ; secondly, the vapors of zinc ; thirdly, the non-volatilizable 
 matters, consisting of scoriae or slag, and of reduced metallic substances of greater density than the 
 zinc. The throat of the furnace being closed, “ the gases arising from the combustion of the fuel” pass 
 
 3300. 
 
 off through the passages A 1 , and are made use of either for the purpose of heating the boiler of ths 
 steam-engine which drives the blowing machine, or to burn lime when used for a flux, or to melt the 
 zinc which is carried over in a state of vapor, or to dry and roast the ores. The “ vapors of zinc” are 
 condensed in the passages F F, and may be easily withdrawn therefrom by means of a rake, (the rec- 
 tangular form of the passages FF affording great facilities for this purpose,) after which they are re- 
 duced and formed into ingots or bars. The “ non-volatilized” or residual matters, which collect on the 
 sole or hearth of the furnace, are run off from time to time according as they accumulate. 
 
 The ores containing zinc may be divided into two classes : firstly, those in a state of oxide, either 
 free or combined with carbonic or silicic acid ; secondly, those containing sulphuret of zinc, (blende.) 
 When the ores are of the first class, (oxides,) they are first dried, and if they contain a carbonate, they 
 are subjected to a roasting process. The flux employed for the treatment of ores of this class is quick- 
 lime, the quantity of which varies according to the quantity of earthy matters contained in the ore, but 
 should be sufficient for the formation of a bisilicate, or, as it is commonly called, a good slag. When 
 the ores contain any other metals, such as iron or lead, these metals are reduced to the metallic state, 
 when they collect on the sole of the furnace, where they arrange themselves in different strata accord- 
 ing to their respective densities, and may be drawn off separately. When the ores are of the second 
 class, (blende,) they are treated in one of two ways : either by roasting, which brings them into the 
 state of oxide, 'which oxide is then mixed with a little damp clay and formed into blocks, which, after 
 being dried, are treated in the manner before described ; or (which is considered the preferable way) 
 these sulphurous ores are mixed with a quantity of iron ore, so that when the metals are fused the iron 
 ‘-hall combine with the sulphur, and set the zinc at liberty. 
 
ZINC. 
 
 9(50 
 
 The flux employed in this case is quicklime ; and if the ore contain a portion of baryta or gypsum, 
 then fluorine is added. The quantity of quicklime employed depends on the quantity of earthy mat- 
 ters contained both in the zinc and iron ores. The iron ore best suited for this purpose is that contain 
 ing zinc, but in too small a quantity to be treated separately as a zinc ore. When, however, the iron 
 ore contains water or carbonic acid, it is necessary that these should be expelled by roasting, in ordei 
 that no substance susceptible of oxidizing the zinc may be introduced into the furnace. If the iron 
 ore contain too great a quantity of oxidating matter, then it is preferable to expel the sulphur from 
 the zinc ore by means of cast-iron or malleable iron. This plan presents the advantage of driving otf 
 the whole of the substances capable of reoxidizing the zinc which has been reduced. When a sul- 
 phuret of zinc in which there are several other metals, such as iron, copper, lead, silver, Ac , is treated 
 in the furnace, there collects on the sole, besides the slag, a stratum of argentiferous lead, on which is 
 superimposed a stratum of cast-iron arising from the excess of iron ore used in the process. Again 
 above the stratum of iron there collects a mass composed principally of sulphuret of iron, sulphuret of 
 copper, and portions of the sulphurets of other metals. 
 
 If white, gray, or yellowish oxide of zinc should be formed accidentally in the passages FF, it can 
 oe made use of directly as a coloring matter, and sold as such ; or else it can be mixed with damp clay, 
 made up into blocks, dried, and again passed through the furnace ; in which case a sufficient quantity 
 of quicklime should be added, to convert all the clay into a fusible slag. 
 
 When ore3 containing zinc in a state of oxide have to be treated, they should be previously assayed, 
 in order to effect an analysis, and to ascertain the quantity of earthy matters contained therein capable 
 of being converted into scoria, and which will determine the proper proportion of quicklime to be 
 added. The lime and magnesia contained in the ore are also taken into account. 
 
 When ores containing zinc in the state of sulphurets have to be treated, the quantities of sulphur, 
 earthy matters, and metallic substances contained therein should also be ascertained by preliminary 
 assay, so that the quantity of iron ore used in the charge shall be sufficient to produce the cast-iron 
 requisite for combining with all the sulphur that may be in the zinc. In order that the combination of 
 the sulphur and iron may be the more completely effected, it is advisable to employ a slight excess of 
 iron ore. But if there should be reason to apprehend that the iron ores might produce too great a 
 quantity of oxidating matter, and thereby create too great a quantity of oxide of zinc, then cast or 
 malleable iron may be directly used for the purpose of combining with the sulphur, in which case the 
 proportion of cast-iron or malleable iron is to be determined by the quantity of sulphur contained in 
 the ore, always employing a slight excess of the iron. The proportion of quicklime or of fluorine used 
 for making a fusible slag will depend on the quantity of earthy matters contained in the ore to be 
 treated, as well as in the iron ore when used for combining with the sulphur. The quantity of fuel 
 employed in this case will depend not only on what has been already stated, but also on the richness 
 and fusibility of the iron ores, and in all cases should be so regulated that the working of the furnace 
 shall in all respects resemble that of a blast-furnace for casting purposes. 
 
 As sulphuretted ores contain generally other metallic substances besides, zinc, a great quantity of 
 reduced metals, and of crude metals, composed principally of sulphuret of iron, will collect on the 
 hearth of the furnace, and combine with the sulphuret of copper and a portion of the sulphurets of 
 the other metals. In this case, therefore, it is better to run off the metal more frequently than in the 
 preceding cases. The lead thereby obtained can be recast into pigs ready for sale, or submitted to the 
 process of cupellation, if it should contain silver ; and any other masses of crude metal may be treated 
 by any of the well-known processes, in order to extract the copper therefrom. As in.the preceding 
 cases, the whole of the zinc will be volatilized, and collected condensed in the passages F F, and 
 chamber G. 
 
 END OF VOL. II. 
 
I N D E X 
 
 Abacus 
 
 Absorbing and Productive! Cas- 
 cade. 
 
 Acceleration. 
 
 Affinity. 
 
 Air Escape. 
 
 Air-Gun. 
 
 Air-Valve. 
 
 Air-V essel. 
 
 Air in motion, or Wind and Wind- 
 Mills. 
 
 Air-Pumps, in general. 
 
 “ Kennedy’s Horizontal 
 Double Cylinder. 
 
 Air-Pipes, 
 
 Alarm, Fire-Damp. 
 
 “ Whistle. 
 
 American Steam Excavating Ma- 
 chine 
 Anchor. 
 
 Anemometer. 
 
 Annealing. 
 
 Angle, Definition of. 
 
 Animal Kingdom, Materials from : 
 as, Porcelanous and Nacreous 
 Shells, Bones, etc. ; 
 Horn ; 
 
 Tortoise-shell ; 
 
 Ivory. 
 
 Anthracite Coal. 
 
 Aqueduct, Wire-Suspension. 
 Aqueducts, Modern. 
 
 Aqueduct, Croton. 
 
 Archimedean Boiler-Furnace, and 
 Self-Acting Stern-Propeller. 
 Artesian Wells. 
 
 “ “ Grenelle’s Bor- 
 
 ing Apparatus of. 
 
 Auger, Ship Carpenter’s. 
 
 “ Improved. 
 
 Augers, Machinery for making. 
 
 “ Double and Single Twist. 
 Auger Machine. 
 
 Automatic Dividing Machine. 
 Axle Grease. 
 
 Axles for turning narrow Curves. 
 ■' Vibrating-Box, for Loco- 
 motives. 
 
 Axle and Wheel. 
 
 Backwater or Scouring rower. 
 
 1 
 
 Ballast-Wagon. 
 
 Ballasting, or Metalling. 
 Balustrade. 
 
 Bar. 
 
 Barrel. 
 
 Barrow. 
 
 Base-Lines. 
 
 Bath-Stones. 
 
 Batter. 
 
 Bearings. 
 
 Beetle. 
 
 Bench, or Berm. 
 
 Beetling Machine. 
 
 Bench-Marks. 
 
 Beton. 
 
 Belting. 
 
 Biram's Tell-Tale. 
 
 Blasting, under water. 
 Blast-Furnace. 
 
 Blast-Pipes. 
 
 Blasting. 
 
 I Block Machinery. 
 
 Blocks 
 
 Blood. 
 
 Bloom. 
 
 Blow-Pipe Analyzer. 
 
 Blowing Machine. 
 
 “ “ or Air-Fan. 
 
 Blow-Pipe. 
 
 “ “ Dr. Hare’s Hydro- 
 
 oxygen. 
 
 Bobbinet Machinery. 
 Boiler-Plates, Machine for Punch- 
 ing. 
 
 Boilers, Varieties of, and circum- 
 stances attending their use and 
 construction. 
 
 Bolting-Mill for Flour. 
 
 Bolts, Iron. 
 
 Bolsters. 
 
 Bond. 
 
 Boring Machine, Vertical, by 
 Messrs. Nasmyth, Gaskell & 
 Co. 
 
 Boring Machine, Great, by the 
 same. 
 
 Boring Machine, Vertical, by 
 Messrs. Benj. Hick & Son. 
 Boring Tools. 
 
 Bow-string Bridge, or Tension- 
 j Bridge. 
 
 Drake, or Convov 
 Bran Separator 
 Breakwater. 
 
 Breakwater Glacis. 
 
 Breasts. 
 
 Breast-W all. 
 
 Brick-Machine. 
 
 Brick-Making. 
 
 Bridges. 
 
 Bronzing, Improvements in. 
 Buffing Apparatus. 
 
 Bullets, Manufacture of by rolling 
 Bung-Cutting Machine. 
 
 Bush. 
 
 Button Machinery. 
 
 Byrnegraph, or new Proportional 
 Compasses. 
 
 Calender, with five Rollers. 
 Calender. 
 
 Calico, Machine for Printing it. 
 
 four Colors. 
 
 Candles, Wax. 
 
 “ Stearine, Manufacture of 
 Cannons, or Great Guns. 
 
 Carding Engine. 
 
 Cask-Gaging. 
 
 Casting and Founding. 
 
 Centre of Gravity. 
 
 Cheese Press. 
 
 Cider Mill and Press. 
 
 Circular Saw for cutting Veneer., 
 Cloth-Shearing Machine. 
 Condensing Machine, by Neilson 
 and Mitchell. 
 
 Coining Machine. 
 
 Connecting Crank. 
 
 Conway Tubular Bridge 
 Cop-Spinner. 
 
 Corn-Mill. 
 
 Coal, Anthracite. 
 
 Corn-Sheller. 
 
 Counter Proportional 
 Cracker Machine. 
 
 Crane, Movable. 
 
 Crane, Foundry. 
 
 Cutting and Carving Machine. 
 Cutting Tools. 
 
 Deal Sawing Machine. 
 
 Derrick, Stone Laying. 
 
2 
 
 INDEX. 
 
 Distillation. 
 
 Diving-Bell. 
 
 Docking Ships, Apparatus for. 
 Dredging Machine. 
 
 Dredging aud Raising Machine. 
 Dresser. 
 
 Dressing Machines. 
 
 Dressing Millstones, Machine for. 
 Drilling Machines. 
 
 Drilling Machine, Vertical. 
 
 Dry Dock. 
 
 Dynamometric Crane. 
 Dynamometer. 
 
 Earthwork, Wagons for Execut- 
 ing. . 
 
 Electricity. 
 
 Electric Light. 
 
 Electric Clock. 
 
 El ectro-Metallurgy. 
 Electro-Motive Engine. 
 Electro-Magnetic Ore-Separator. 
 Elevators. 
 
 Elliptograpb. 
 
 Embossing Machine. 
 Embankments, Movable Machine 
 for executing. 
 
 Engines, Details of: 
 
 Pumping Engine. 
 
 Rotative Engines. 
 
 The Parallel Motion. 
 
 Marine Engines. 
 
 Boilers. 
 
 Locomotive Engine. 
 
 Fire-box. 
 
 Stnoke-box and Chimney. 
 Framing. 
 
 Steam-dome, pipes, and regu- 
 lator. 
 
 Safety-Valves and Fusible 
 Plugs. 
 
 Cylinders and Valves. 
 
 Wheels. 
 
 Cranked Axle. 
 
 Connecting-rods. 
 
 Eccentric and Eccentric-rod. 
 Valve motion. 
 
 How to set the Valves of Loco- 
 motives. 
 
 Miscellaneous Remarks respect- 
 ing Locomotives. 
 
 Rules for Calculating the Parts 
 
 of. 
 
 Varieties of the Steam En- 
 gine. 
 
 Eng-raving on Copper 
 “ on Steel. 
 
 “ on Stone. 
 
 on Silver and Gold. 
 
 “ on Wood. 
 
 Envelope Machinery. 
 
 Etching. 
 
 Fan. 
 
 Falling Stocks. 
 
 Felloe Machine. 
 
 Felting. 
 
 Files. 
 
 File and Rasp Machine. 
 
 Filing. 
 
 Filtration. 
 
 Fire-Annihilator. 
 
 Fire Bricks. 
 
 Fire-Engine. 
 
 Flash-Boards. 
 
 Flax, Machinery for Preparing 
 and Spinning. 
 
 Floating Sectional Docks. 
 Floor-Cloth. 
 
 Fly-Wheel. 
 
 Focus. 
 
 Folding and Measuring Machine. 
 Force. 
 
 Forge. 
 
 Forging. 
 
 Fortification. 
 
 Foundations. 
 
 Foundry Crane. 
 
 Freezing Apparatus. 
 
 Friction. 
 
 Friction-Rollers. 
 
 Fringe Machine, Shawl. 
 
 Frog. 
 
 Fulcrum. 
 
 Fulling. 
 
 Fulling-Mill, for Cloth. 
 
 Furnace. 
 
 “ Reverberatory. 
 
 Fusible Metals. 
 
 Futtock, or Ship Timber Convert- 
 ing Machine. 
 
 Futtock Plates. 
 
 Futtocks. 
 
 Galvanism. 
 
 Galvanized Iron. 
 
 Galvanometer. 
 
 Gas, and the Machinery employed 
 in the Manufacture of. 
 
 Gates, Wrought-iron, for the Uni- 
 ted States Dry Dock at Brook- 
 lyn. 
 
 Gates, Floating, for the United 
 States Dry Dock at Brooklyn. 
 Gates, Guard. 
 
 Geer Cutting Machine, Bevel. 
 Geer Cutting Engine. 
 
 Geering. 
 
 Geodesy. 
 
 German Silver. 
 
 Gig-. 
 
 Gilding. 
 
 Gimbals or Gimbols. 
 
 Gin. 
 
 Glass. 
 
 Glue. 
 
 Glyphograpliy. 
 
 Gold. 
 
 Gold-Beating. 
 
 Goniometer. 
 
 Governors. 
 
 Grain Separator. 
 
 Graphometer. 
 
 Gravity, Centre of. 
 
 Gravity, Specific. 
 
 Grinding Machine, Double. 
 
 | Grinding Mill, Eccentric, 
 i Grindstone. 
 
 1 Grist-Mill. 
 
 ' Gage, Steam and Water-Safety, 
 for Steam boilers. 
 
 Gage, Telegraphic Steam. 
 Gudgeon. 
 
 Guns. 
 
 Gun-Barrels, Lathe for Turning. 
 Gun-Cotton. 
 
 Gun-Metal. 
 
 Gunpow T der. 
 
 Gunter’s Chaim 
 Gunter’s Line. 
 
 Gunter’s Scale. 
 
 Gutta Percha. 
 
 Gyration, the Centre of. 
 
 Hammer, Anderson’s patent 
 Hammer, Steam. 
 
 Hammer, Tilt or Trip. See Tilt- 
 ing. 
 
 Harvester. See Reaper. 
 Hat-Making. 
 
 Hay and Corn Cutter. 
 Heart-Wheel. 
 
 Heat. 
 
 Heddles, Machine for making 
 Weavers’. 
 
 Heliotrope, Reflecting Lantern. 
 Heptagon. 
 
 Hexsedron. 
 
 Hexagon. 
 
 High-Pressure Engine. 
 High-Pressure Steam-EngiQc. 
 Hinge. 
 
 Horn. 
 
 Horse. 
 
 Horse-Power. 
 
 Horse-Shoe. 
 
 Hydrodynamics. 
 
 Hydro-Electrical Machine. 
 Hydro-Extractor. 
 
 Hydrometer. 
 
 Hydrostatic Press. 
 
 Hygrometer. 
 
 Hyperbola. 
 
 Hyperbolic Logarithms. 
 
 Ice. 
 
 Ice-Boats. 
 
 “ House. 
 
 “ Saws. 
 
 “ Trade. 
 
 Icosahedron or Icosaedron. 
 Illumination. 
 
 Impact. 
 
 Impenetrability. 
 
 Impetus. 
 
 Incidence. 
 
 Inclination. 
 
 Inclined Plane. 
 
 Indicators. 
 
 Indigo. 
 
 Inertia. 
 
 Involute Curve. 
 
 Iron. 
 
 Jack. 
 
 Jack-Screw. 
 
 “ Lever. 
 
 “ Traversing Screw. 
 
 “ Traversing. 
 
 Jacket, Steam. 
 
 Jacquard. 
 
 “ Perforating Machine 
 Japanning. 
 
 Joint, Clasp Coupling. 
 
 Joint, Patent Expansion. 
 
 Joints, and Joining Timbers, 
 
 Kaleidoscope. 
 
 Kedge. 
 
INDEX. 
 
 3 
 
 Iveel. 
 
 Keelson. 
 
 Kiln. 
 
 Kite. 
 
 Kneading. 
 
 Knives. 
 
 Knife Sharpeners. 
 
 Laburnum Wood. 
 
 Lac. 
 
 Lace. 
 
 Lacquering. 
 
 Lactometer. 
 
 Ladder. 
 
 Lamps. 
 
 “ Spirit Gas. 
 
 Lathe for Turning Irregular 
 Forms. 
 
 Lathe for Small Engine. 
 
 “ Boring and Reaming. 
 
 “ Engine. 
 
 “ Large Boring and 
 
 “ Reaming. 
 
 “ Gun Boring, Turning, 
 
 “ and Planing. 
 
 “ Small Self-acting and 
 
 Screw Cutting. 
 Boring and Turning. 
 
 “ Boring-Mill and Large 
 
 Turning. 
 
 Lap and Lead of the Slide-Valve. 
 Lead. 
 
 Lens. 
 
 Lever. 
 
 Lewis. 
 
 Light. 
 
 “ Artificial. 
 
 Light-Houses. 
 
 Lightning Conductors. 
 
 Life-Boat. 
 
 Lime. 
 
 Lithography. 
 
 Lochs of Canals. 
 
 Locomotive Engine. 
 
 Logarithm. 
 
 Logwood. 
 
 Loom, Power. 
 
 “ Bigelow’s Counterpane. 
 
 Double-Stroke. 
 
 " Power Carpet. 
 
 Machines. 
 
 Magnet — Magnetism. 
 
 Mahogany. 
 
 Manometer. 
 
 Mangle. 
 
 Maple- Wood. 
 
 Marble Sawing and Polishing Ma- 
 chinery. 
 
 Marine Steam-Engine. 
 
 Matches. 
 
 Materials. 
 
 Mean. 
 
 Measure. 
 
 Mechanical Powers. 
 
 Mechanical Power of Steam. 
 Mensuration. 
 
 Metals and Alloys. 
 
 Metallurgy. 
 
 Micrometer 
 
 Microscope. 
 
 Mile. 
 
 Mill. 
 
 Millstone. 
 
 Mineral Kingdom. 
 
 Mines, Engines for. 
 
 Modulus. 
 
 Momentum. 
 
 Mortar. 
 
 Mortising Machine. 
 
 Motion. 
 
 Moulding Machine. 
 
 “ “ Sheet-Metal. 
 
 Mule. 
 
 Nail Machine. 
 
 Needles. 
 
 Nickel. 
 
 Nonagon. 
 
 Normal. 
 
 Nut-Cutting Machine. 
 
 Octagon. 
 
 Octahedron. 
 
 Odometer. 
 
 Oils. 
 
 Oil Test. 
 
 Ombrometer. 
 
 Operameter. 
 
 Opsiometer. 
 
 Ordinate. 
 
 Ore-Separator. 
 
 Orthochronograph. 
 
 Oscillation, Centre of. 
 
 Oscillating Engines. 
 
 Oyster Opener. 
 
 Paints, Grinding of. 
 
 Paper, Manufacture of. 
 
 “ Cutting. 
 
 Parallel Motions. 
 
 Parameter. 
 
 Pendulum. 
 
 Pens, Steel. 
 
 Percussion. 
 
 Percussion-cap Machine. 
 Perpetual Motion. 
 
 Persian Wheel 
 Photography. 
 
 Photometer. 
 
 Pile-Driver. 
 
 Piling Machine. 
 
 Pin-Making Machine. 
 
 Piston. 
 
 Planing Machine. 
 
 “ “ Hand. 
 
 Plate-Bending Machine. 
 
 Platinum. 
 
 Pneumatics. 
 
 Polarization of Light. 
 
 Potassium. 
 
 Press, Anti-Friction Cam. 
 Printing-Press, Lithographic. 
 Press, Progressive Lever Steam. 
 Printing-Press. 
 
 Projection. 
 
 Proving Machine, Hydrostatic. 
 Puddler’s Balls, Machine for com 
 pressing. 
 
 Pulley. 
 
 Pumps. 
 
 “ Steam. 
 
 Punch, Revolving Steam. 
 Punching Machine, Steam 
 Punching and Plate-Cutting Ma- 
 chine. 
 
 Punching and Shearing Machine 
 Pyrometer. 
 
 Picker, Rag and Waste. 
 
 Railroads. 
 
 Retorts. 
 
 Rice-Cleaner. 
 
 Rivets and Blank Screws, Ma- 
 chine for making. 
 
 Riveting and Steam Punching 
 Machine. 
 
 Rolling Machine. 
 
 Ropes, Stiffness of. 
 
 Sawing Machine. 
 
 Saw-Filing Machine. 
 
 Screws, Self-ojierating Shaver. 
 Screw-Blanks. 
 
 Screws, Burring Machine for 
 Screw-cutting Machine. 
 Screw-Finisher. 
 
 Screws, Machine for Nicking. 
 
 “ Machine for Shaving and 
 Turning. 
 
 “ Machine for Threading, 
 Screwing Machine for Bolts. 
 
 “ “ "tauble. 
 
 Sea-Lights. 
 
 Seaming Machine. 
 
 Sewing Machine. 
 
 Shears, Rotary. 
 
 Sliingler. 
 
 Shingle Machine. 
 
 Shot. 
 
 Slotting Machine. 
 
 Sluice-Cocks. 
 
 Smut Machine. 
 
 Soldering. 
 
 Spike Machine. 
 
 Spinning-Frame Banding, Ma 
 chine for making. 
 Stave-Dressing Machine. 
 Stave-Joining Machine. 
 
 Steel. 
 
 Strength of Materials of Con 
 struction. 
 
 Sugar-Mills and Machinery. 
 Switch. 
 
 Telegraph. 
 
 Telescope. 
 
 Tempering, Hardening, and Soft 
 ening Metals. 
 
 Thermometer. 
 
 Threshing Machine. 
 
 Throstle. 
 
 Tilting Hammer. 
 
 Tobacco-Cutting Machine. 
 
 Tools, Cutting, Drilling, Turning 
 &c. 
 
 Torsion. 
 
 Transit. 
 
 Trip-Hammer. 
 
 Tube-Cocks. 
 
 Turbine. 
 
 Turn-Table. 
 
 Twisting Machine for Iron. 
 Uranium. 
 
 , Valves. 
 
 I Valve, Expansion. 
 
 | Velocity. 
 
4 
 
 INDEX. 
 
 Ventilation. 
 
 Vernier. 
 
 Vice, Lever. 
 
 "Warming and Ventilation. 
 Watchmaking. 
 Water-Closet 
 Water-Metre. 
 
 W ater Pressure Engine. 
 Water- Wheels. 
 
 Weights and Measures. 
 Wheels, Railway. 
 Wheels, Paddle. 
 Wire-covering Machinery 
 Wire Rope Machinery. 
 Wiring Machine. 
 
 Woods, Variety of. 
 
 Wood, Steam Carbonizing Ma 
 chine. 
 
 Wrench, Cylinder. 
 
 Wrench, Screw. 
 
 Zinc. 
 
 Boilers, American. 
 Brick-Making Machine. 
 
 Cart-Wheels. 
 Cask-Making Machine, 
 
 Iron Rolling Machine 
 
 Placing Machine. 
 
 APPENDIX. 
 
 Pumping-Engine, from the United 
 States Dry Dock at Brooklyn. 
 
 Railway Bars. 
 
 Regulating and Numbering Ma- 
 chine. 
 
 Smut Machine. 
 
 Spark Arrester 
 Stove, Cooking. 
 
 Sugar, Manufacture of 
 
 Tube-Making Machine 
 
 Sewing Machine, 
 
 Valves. 
 

 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
GETTY RESEARCH INSTITUTE 
 
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