MANUAL TRAINING Made Seroiceable to the School >R. WOLDEMAR GOETZE fyxmll ^uivmity ptag BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OP Stettrg M, Sage 1891 rivet this into the base. Next cut the cone and round it. To allow the wire bow to pass through, holes are punched in the jacket of the cone; then the latter is soldered together so that the apex is somewhat blunt. Cut the wire for the bow ; bend it, and solder it into the cone. Lastly, make the side weights of brass tubing ; cut bottoms for them and solder on. Fill with -molten lead, so that the metal as it cools holds the ends of the wire bow. 38. Candlestick for experiments with concave mirror and lenses. The candlestick is made of iron plate and hoop iron. Dimensions: — diameter of base, 11*5 cm. ; height of candlestick, 30 cm.; breadth, 13 cm.; difference in height between the upper and the two lower candleholders, 11 -5 cm. ; breadth of the hoop iron, 1 - 3 cm. ; thickness of the same, 2 - 5 mm. In making, we first cut the three pieces of hoop iron of which the candlestick consists, and bend the two outer ones rect- angularly in the vice. Then punch the holes for the rivets which are afterwards to join the three pieces into one, and file the ends into spike shape to receive the candles. Now rivet the three pieces together and make a tenon at the bottom. To make the foot, cut a disc of iron plate, hammer it concave, cut the hole for the tenon, and rivet the latter into the foot. Lastly, cut three small discs (diameter, 2 - 5 cm.) of iron plate make holes in them, and fit them on to the iron spikes. 39. Fixed and movable pulleys. (See Bench- Work No. 7.) The two pulleys can be applied equally well to the 4 J- Metal- Work 133 same side of the upright, and the whole apparatus except the grooved wheels (best obtained from the turner), of hard wood, can be made of metal. In that case we need for the base, iron plate ; for the upright, squared bar iron ; for the supporters, iron wire ; for the weights, brass tubing and brass plate. ' Dimensions : — base, 18x12 cm. ; height of the upright, 30 cm. ; cross-section, 1 - 5 cm. square. Order : — First the plate for the base is cut, and the edge strongly hammered to make the base rigid. Then the squared bar iron is cut for the upright, a tenon is made at the bottom, holes are drilled to enable us to apply the pulleys (the grooved wheels), and the upright is riveted into the base. The supporters are made by twisting two wires together, bending them at right angles, and riveting them into the holes already drilled in the uprights. For the weights we cut brass tubing, and discs of brass plate for their bottoms. Fill with molten lead, so that, as before, a handle of brass wire is gripped by the cooling metal. 40. Binding screws — two kinds of. (See Weinhold, Vorschule der Experimmtalphysik, p. 423 ; English transla- tion, p. 657.) For the first we need thick sheet brass and brass wire. A piece of sheet brass of the re- quisite size is cut, filed straight, and bent round a piece of flat iron. In one arm we drill a hole and cut in it a hollow screw. To make the screw to fit into this, a piece of brass wire is bent at right angles and a screw cut on one of its arms. The second kind of binding-screw is for connecting wires to establish an electric circuit. To make it, we need a strong 1 34 Manual Training made serviceable to the School cylinder of brass and brass wire. From the cylindrical bar of brass we cut with the saw a piece of suitable length, and bore therein four holes, two for the wires and two for the screws, which enter from the sides. In the two latter holes hollow screws are cut. We next bend two hooks, cut screws at their straight ends, file the whole clean, and finish. 41. Magnetic needle balanced on pivot -stand, with binding screws and wire arch. The magnetic needle, 8 cm. long, 1 cm. broad, made from a steel plate - 6 mm. thick, has in the middle a small cap, thrust through a hole and riveted in. This cap is made from a piece of brass wire, 5 mm. long, 3-5 mm. thick, in which a hole 4 mm. deep, 2 mm. wide, is drilled. The rim of the foot of the stand (foot cut from brass plate - 65 mm. thick, diameter 56 mm.) is curved downwards on a bordering iron with rounded edge, and hammered true on the big punch, which is fixed in the vice ; then the cut edge is filed level. To obtain a better hold of the foot whilst polishing with emery, we solder to it on the inside a metal handle. It is now turned in the Metal -Work 135 hollow of the hand with oiled emery "paper, thus acquiring a circular grain, as it were. The brass upright (6 cm. high, 3 - 5 mm. thick) is provided at the bottom with a ^ inch screw, passed through the foot and secured with a nut made from brass plate 1 - 7 mm. thick. This nut, which is rectangular, is not visible in the drawing. In the top of the upright a hole is made, into which a needle is soldered, and serves as a pivot on which the magnetic needle may be balanced. The binding-screws (18 mm. long) are sawed from quad- rangular brass wire (8x8 mm.), the cut surfaces being filed true. 6 and 12 mm. from the front edge we drill two vertical holes right through the wire, and a similar hole horizontally in the front surface to a depth of about 10 mm. In the horizontal hole in each part a \ inch female screw is threaded. The screws to fit are of brass wire, 3 - 5 mm. thick ; on them are riveted and soldered discs of metal, li mm. in diameter, and having milled edges. By means of wood screws, which go through the back vertical holes, the binding screws are fastened to a varnished alder board (16 x 13 x 1 cm.). The wire arch (brass or copper wire, 40 cm. long, 1 - 7 mm. thick) is bent in fork shape at the ends ; the fork points are fixed in the wood; the wood screws passing between the prongs secures the arch as well as the binding-screws to the board. (Bericht der Lehrerbildurujsanstalt fur Knaberiliandarbeit, 1891.) 42. Peal of electric bells. Material : — brass plate, thick and thin brass wire. Dimensions : — width of the curved upper piece, 8 cm. Order : — bend first the wire for the upper piece, making a large loop in the middle, a smaller one at each end. The bells are made by cutting discs (6 - 5 cm. in diameter), beating them concave, and then polishing them. Holes are made in the bells to enable us to suspend them. The bell shown in the drawing on the right is insulated by being hung on a silk thread ; it can be brought into connection with a conductor by means of a silver thread, or of a short chain simply made with links of brass 1 36 Manual Training made serviceable to the School wire, the links endirfg at either end in a hook. Through the hole in -the bell there is a short wire also terminating both above and below in a hook ; we are thus able to attach the bell to the silk thread and also to the chain. The other bell is not insulated, but its electricity is conducted off to the earth. Thus it hangs on a brass wire bent at top and bottom into a hook, and at the bottom catches in a hook on. the bell. The slapper hangs insulated on a silk thread ; the hammer part is cut from thick brass wire, filed to shape, and having a hole bored through its upper end. If electricity be conducted to the right-hand bell, it attracts the clapper, and is communicated to it ; hence the clapper, being charged with like electricity, is repelled. The clappei swings to the other bell, and discharges its elec- tricity into it, with the natural consequence that the electricity is conducted to the earth with which the left-hand bell is connected. The clapper having thus become non-electric, the same process is repeated. 43. Weighing machine. Material : — iron plate, hoop iron for the framework and the beam, zinc plate, brass plate, iron wire, brass wire. The base (27 x 15 cm.) is made of iron plate. To give it stability, its four edges are bent at right angles, so that sides are formed to the plate con- stituting the base. The hoop iron employed is 13 mm. wide and 2 "5 mm. thick; the upright is 30 cm. high; the two low supports are 8 cm. high ; the beam has Metal- Work 137 a length of 30 cm. The upright consists of two strips of hoop iron ; in these when they have been cut we punch holes for the rivets and axle of the beam; the feet are then bent at right angles and the strips riveted together above. In like manner we make the two low supports for the scale ; but in one of them there is — not a hole — but a slit narrowing towards the top and enabling us to lay an axle easily in position. Upright and supports finished, we punch holes in the base, and so can rivet the four pieces in their places. ~N&xt comes the making of the weighing-beam. It consists of three parts, a long middle part and two shorter parts, which are only one-third as long as the middle part. These two pieces together form the shorter beam (in the drawing, the one to the right), and are joined together by means of rivets. Holes for the weight-pans and for the axle are then bored through the beam. We now make the weight-pan to the left of zinc plate, 5 cm. square, the rim 5 mm. high. To suspend it, we bend a piece of iron wire into the shape to be seen in the drawing ; on the top of this wire we bend a 138 Manual Training made serviceable to the School hook ; at the bottom we bend at right angles, hammer flat, and solder on the weight-pan. We further need for the suspension of the pan a claw, 12 mm. wide, 5 cm. long, bent over the beam and riveted to it, whilst below the beam the fork is pierced to admit an axle, on which finally the hook of the iron wire is hung. The two round weight-pans, those to the right in the draw- ing) are next cut from brass plate (diameters, 2 - 5 cm. and 4 - 5 cm.), and hammered somewhat concave ; through the edges at equal intervals three holes are punched, as also a hole in the middle. To suspend each of the pans, three wires are used, one set each 9 - 5, the other set each 11 cm. long. The three are twisted together at the top, formed into a hook, and so attached to the beam ; at the bottom each is passed through a hole in the pan and secured by a loop underneath. In the middle holes of the pans small brass-wire hooks are riveted, and in each of these hooks again hangs a piece of wire terminating in its turn in a hook. It is now time to make the lower weighing-beam. This is done with hoop iron 12'5 cm. Taking a piece of hoop iron, 25 cm. long, 13 mm. broad, but only 1*5 mm. thick, we bend it together in the middle, and then, 1 "5 cm. from the bending-point, draw it apart into an acute angle. A hole is drilled in the double end so as to allow the beam to be connected with the larger of the two weight- pans above ; through the divergent ends holes are also drilled, a straight iron rod thrust through these holes and laid as an axle in the two low supports of the scale. The scale or large weighing surface (24 x 10 cm.) is cut from zinc plate, sloped away towards the side where the upright is, the edge bent at right angles all round to a width of 5 mm., the corners soldered. To let the wires through which hang down from the circular weight- pans, there must be made through the scale a small hoje, and more towards the middle a larger one. — We must next make a blade of tin plate, 9 cm. long and Metal- Work 139 3 cm. broad ; 1 cm. of the breadth is bent over at a right angle and soldered on to the under side of the scale. On the same side two small tin-plate strips are fixed, serving as supports for a pieee of iron which can be thrust backwards and forwards and produce equili- brium. In the knife hangs, lastly, another weight-pan. We cut it (5 cm. square) from zinc plate, and bend up the edges 5 mm. all round. "We next bend a piece of iron wire to suspend this weight-pan. At the top there is a hook; at the bottom we bend, as before, at a right angle, flatten, and solder the weight-pan on. The upper hook is fixed in a hole in the knife. 44. Element of chromic acid battery. (See Glass- Work, No. 16; and, for cover, Bench- Work, No. 25.) We use a glass bottle the top of which has been sprung off; about the upper edge we lay a strip of brass 2 cm. wide, cut from thin brass plate, bent round, and soldered together at the ends. On the under side of the wooden cover is a strip 140 Manual Training made serviceable to the School of thin copper plate (see section). This is cut 25 mm. wide, and hent to shape. It then has five holes made in it ; a larger one in the middle and four smaller ones at the corners, the latter to screw it on to the cover. At the end of each bent arm of the copper strip two other holes are made ; these are to enable us to rivet the carbon on. The carbon, however, cannot be riveted directly to the copper strip, but two leaves of thin plate are laid on either side of each carbon block and the latter is riveted in between them to the copper strip. The binding- screw to the left in our drawing is driven through both the wooden cover and the copper strip, then riveted below the latter. Thus it estab- lishes the connection of the two carbon blocks with the conducting wire. As this screw has to go through the wooden cover, it will be best to use for it a wood screw, which, its head snapped off, is soldered into the binder. The binding-screws themselves are made of thick round brass. For the zinc plate, which must be capable of being moved up and down, a guide must be made. We first cut from brass plate a strip, 3*5 cm. long and 13 mm. wide, and punch in it four holes, two to enable us to screw the strip in its place, one for the binding-screw to the right, and one for the guiding-pipe of the zinc plate. Into this last hole a socket of brass tubing, 2 - 5 cm. long, is soldered. The socket is for the. rod on which the zinc hangs. Now the right-hand binding-screw, which connects with the zinc, is riveted into the brass strip, and the guiding-rod is made from brass wire. The rod has a small disc of brass soldered on to its end and serving as a handle. At its lower end the rod is joined to the zinc plate by screws or by soldering. Of course, there must be no contact between the rod and the blocks of carbon between which it passes ; it is likewise necessary that there should be a space between the left binding-screw, which is connected with the carbon, and the brass strip in which is fastened the binding-screw for the zinc. All being now ready, we, last of all, screw the brass strip on to the cover. Metal- Work 141 45. Ruler with square cross-section. The length of this ruler is 30 cm. ; the thickness, 15 mm. The square iron is B IS lilPllil'ilillllili'li'ill'ill^ 1 ^.'''' ■ - ^ ■»yv> T *vwv» w .>K> sg la^ ■* A r~ 1 1 p WW carefully made, the angles made true with the rough file, and the -whole smoothed with a fine file. After the filing, the surfaces may he finished with coarse emery paper. 46. Ruler with chamfered edge. Length, 30 cm. ; breadth, 30 mm. ; thickness, 7 mm. The flat iron bar is prepared and filed. On one side a chamfer (5 mm. wide) is filed, and 15 mm. from one end an 8 mm. hole is drilled. 47. Handscrew. The bow is of flat iron, 20 mm. wide, 7 mm. thick. A piece 18 cm. long is cut off, and marks of division are made, so that one part is 2 cm. shorter than each of the two others. A small cut is made, which shows, when the iron is red-hot, where the bend is to be. The iron, heated to redness at the points of division, is fixed in the vice and bent at right angles. In the shorter arm we drill, 12 mm. from the end, an 8 mm. hole, and in it cut a screw with the 10 mm. screw-tap. The length of the inserted screw corresponds with that of the upright arm of the bow ; the screw is made of round bar iron, 10 mm. thick. At one end of it, a cut, 1 cm. long, is made with the saw, and a plate (3 mm. thick) let into the cut, square ear of iron Screw and ear are then hard soldered (i.e. soldered with brass). The ear 142 Manual Training made serviceable to the School when cold may be worked with the file into an elegant form, say, a heart shape. On the other end of the screw a round tenon is cut, and then the thread is made with the screw- stock, so that the screw just fits into the female screw. A small cup is fixed on the round tenon at the top of the screw. This cup is about 25 mm. in diameter, and is made from iron plate, 1 mm. thick, cut round, and then shaped with the punch on a sheet of lead. The size of the bole in the cup must correspond with that of the tenon, so that the cup can turn on the tenon. Bow and ear of screw are now filed with rough and bastard files, and the tenon somewhat flattened at the end, so that the cup may not fall off. 4,8. Tools — chisels, punches, drills. All these tools are made of cast steel, 8 mm. thick, and are from 8 to 10 cm. long. The cast steel is heated to redness, beaten out somewhat on the anvil — the •chisel on two sides, so that an edge is formed ; the four-cornered punch on four sides, but so as to leave at the end a square surface of 3 or 4 mm. side. The round hollow punch is beaten to a circle at the end, and also has there a surface 3 or 4 mm. in diameter. Lastly, of the drill. The metal is beaten out on four sides, and then flattened on one side to the thickness of 1 - 5 mm. ; the breadth will depend on the size of the hole which we propose to drill with it. The tool-ends remain on the bar during the hammering process, so that they may be the better held. It is only after the hammering that the mark of division is cut into with the triangular file ; we then fix the bar in the vice up to the point indicated, and break off. Afterwards we use rough file and finer file on the Metal- Work 143 detached pieces, according to the purposes for which they are intended. This done, they are again heated to redness in the fire, and cooled off in clean cold water, cooled, however, only for about 1 - 5 cm. of their length, so that the heat remaining can do the blueing. The cooled part is rubbed with sandstone until one can see the colours — yellow, red, and blue. If the blue is duly there, the whole tool is again cooled, and will now possess the requisite hardness. (See Bericht der Lelirerbildungsanstalt fur 1891.) 49. Metal parts for cylinder of steam-engine. (See Bench-Work, No. 35.) Axle and piston-rods are of iron wire, the cranks of brass. The two piston-rods have a screw made at the bottom and a loop at the top. The cranks are cut of brass 6 cm. long, and a slit is filed in their lower ends. It is in the slit that the loops on the piston-rods move. Small holes are drilled through the sides of the slits, and bolts are fixed through these holes to catch the loops. In the cranks, beginning at the middle of their long sides, we file the metal away towards the back top corners, and thus produce a cavity in which the wire of the axle can turn freely. To keep the axle from leaving the crank when rotation takes place, we bore through the crank in a direction at right angles to the axle, small holes, make female screws in these holes, and then fit in small screws. The axle is thus connected with the cranks. The wire of the axle is bent into rectangular loops, the depth of the loop depending on the height to which the parts of the cylinder are lifted. In our .model, the bend for the piston is 2 '5 cm. deep, for the block illustrating the action of the valves l - 5 cm. The end of the axle which projects beyond the frame is hammered flat, then pointed, and fixed in the turning-disc. Lastly, in the other side of the disc, we fasten a small iron rod to serve as a handle enabling us to work the machine. 50. Electric bell. This arrangement is familiar enough ; it must, nevertheless, not be missing from our course. The various parts are mounted on a small board, as shown. The 144 Manual Training made serviceable to the School electro-magnet consists of a bow of iron wire, 7 mm. thick, on which are the coils of copper wire about the iron cores. The magnet is fastened to the board by means of a strip of wood, through which passes a wood screw drawing the strip towards the board. In front of the magnet is an armature of soft iron, into a hole in which the hammer of the bell is soldered fast. On the outside of the arma- ture a spring is soldered. This spring is, at its upper end, fastened sideways by means of screws in a brass cramp screwed on to the board. The lower, movable end of the spring passes to a second cramp, also of brass, and also secured to the board by screws. Through the arm of the cramp which stands out from the board a screw works, and is so arranged that, when the machine is at rest, its end is in contact with the spring ; whereas, as soon as the armature is attracted by the magnet, the spring leaves the screw. At the right and left top corners of the board binding-screws are fastened, and to them the wires from the battery lead. The bell, 9 cm. in diameter, is beaten out from brass plate. It rests on a pin of brass wire, the ends of which are filed down, and have screws threaded on them. The pin is fastened to the board by a nut underneath, fitting into a hole made for the purpose. This nut is of brass plate, and is rectangular ; another nut of the same material, but round, secures the bell to the pin. One end of the copper wire coiled round the magnet is connected with the binding-screw to the left ; the other leads across to the lower brass cramp, and establishes the connection therewith. From the lower the current is conducted through the spring to the upper cramp, which in Metal- Work 145 its turn is connected with the binding-screw to the right, so that the circuit is thus completed. As soon as the current circles round the magnet, the armature is attracted, the hammer strikes the bell and causes it to sound. The current is, however, interrupted ; for with the movement of the armature the spring is removed from the screw on which it lay. The magnet loses its power of attracting; conse- quently the armature, drawn by a spring, reverts to its old position. The circuit is thus again completed, and the process begins anew. 51. Rotation apparatus. A composite work, the masterpiece of the course, yet not so difficult after the preceding exercises that a boy will be unable to cope with it. It is a contrivance for utilising the attractive f orceof anelectro- magnet to produce continual motion. Instead of a horse- shoe magnet, which, as it can only be bent while the metal is 146 Manual Training made serviceable to the School hot, is harder to make, we use two pillars of round bar iron. These pillars are 11 *5 cm. high, and 10 mm. thick, and are joined at the top by a cross-piece of flat bar iron, 10 cm. long, 1 "5 cm. wide, and 5 mm. thick. Both pillars are filed down at top and bottom, and screws are threaded. The screws at the bottom enable us to fasten the pillars to the base-board. This is done by means of nuts screwed upwards and resting in holes made to receive them. The screws at the bottom serve for uniting the pillars : for holes being bored in the proper places in the cross-piece, the latter is laid across the wire coils and attached to the pillars by nuts. On the upper surface of the base-board lies a strip of thin brass plate connecting the two pillars. This is fastened to the wood along with the pillars. It supplies a bed for the rotating axle, inasmuch as the conical lower extremity of the axle works in a small pit in the middle of it. The upper end of the axle has also a small pit made in it, the point of a screw passed through the middle of the cross-piece working in that pit. This screw and the axle are alike made of iron wire 3 '5 mm. thick ; the axle is 9*5 cm., and the screw 2'5 cm. long. Between the two pillars is a straight magnet turning with the rotating axle, to which it is affixed as follows : — The iron core in the straight electro-magnet has a hole drilled in the middle ; the axle is then thrust through and soldered in its place. Instead, however, of soldering, we may drill a hole sideways in the iron {i.e. a hole perpen- dicular to the previous one), cut female screw, and insert therein a screw ; this screw will bind the axle in position. The latter method is better, as, whilst the connection made is strong enough, the screw enables us to fix the rotating magnet higher or lower, as need may be. — To increase the mutual attraction and repulsion of the two electro-magnets, curved pieces of iron are affixed both on the inside at the base of the pillars, and at either end of the rotating magnet. These curved pieces or bows are made of hoop iron, 2 cm. broad,, and 5 mm. thick, rounded over a mandrel. The two Metal- Work 147 outer bows are cut, each 5 cm. long, the two inner each 4 - 5 cm. The ends are bevelled and neatly filed. In the middle of each piece a hole is made ; the holes in the outer pieces enable us to rivet them to a flat surface filed on the pillars ; those in the shorter pieces allow these to be riveted to the ends of the rotating magnet. Near the front long-edge of the base-board are two binding- screws, made of brass in a way that will be by this time familiar (Metal- Work, No. 41). Between them, near the same edge of the board, and opposite the rotating axle, are two small uprights, 5'5 cm. high, and made of thick brass wire. These are soldered at the bottom into little squares of brass plate, the brass squares being attached to the board by screws. The tops of these uprights are filed down, and round them are soldered the looped ends of two strips of brass. The strips, 5 mm. deep, and hammered to act like a spring, are directed on to the axle, and work against a thickening of it in a way that will be understood from the side drawings, which give vertical and horizontal sections of the thickened axle. The thickening of the axle is produced as follows : — First we wrap several times round it, above the rotating magnet, a strip of paper, 3 cm. broad, and smeared with glue. The diameter of the paper cylinder thus produced should be 9 mm. To prevent this paper cylinder from slipping round the iron wire which forms its core, we, before rolling the cylinder, solder two bits of brass to opposite sides of the wire, and work them with the file so that they catch in the paper like hooks. We next make a socket of thin brass plate and cut it lengthways into two parts. The socket is 2 '5 cm. long ; the curve depends on that of the paper cylinder, upon which the two halves are so fixed that small strips of the paper are visible between them. Thus, when the machine is rotating, the two brass springs are alternately in contact with the half-sockets and with the paper of the cylinder. To keep the half-sockets in place, we roll round them another but narrower strip of paper, 9 148 Manual Training made serviceable to the School mm. wide, and smeared as before with glue. The technical construction of the rotation apparatus is now finished. The manner of connecting the wires is exhibited in the drawing. The wire is conducted from the right-hand (in drawing) binding-screw to the right-hand pillar, and coiled round it. At the top the wire passes under the iron cross- piece to the left-hand pillar, is coiled about it, and passes thence under the right-hand brass upright, the connection with the right-hand spring, the axle, etc., being thus estab- lished. A small piece of covered copper wire passes from the square plate in which the left-hand upright is fixed, to the left-hand binding-screw. In wrapping the rotating magnet, we place one end of the copper wire under one half of the brass socket, coil to one end of the magnet and back, then coil from the middle of the magnet to the other end and back, then thrust the end of the wire under the second half of the socket. The current passes from the right-hand binding-screw, in which has been fastened a conducting- wire from a battery, to the right-hand pillar, circulates round it, is conducted over the cross-piece to the left-hand pillar, circulates round that, passes to the right-hand brass upright and through the right-hand spring to one half-socket on the axle, then, circling round the rotating magnet, is conveyed to the other half-socket, thence to the left-hand spring and left-hand upright, and then from the foot of the latter to the left-hand binding-screw, in which the second conducting- wire from the battery has been fixed. The" circuit is thus complete. We may now explain by reference to the drawing the principle on which the rotation is produced. If the right- hand binding-screw is connected with the positive pole of the battery, the foot of the right-hand pillar is a south pole, that of the left-hand pillar a north pole. As long as the current passes from the half-socket which is now to the right end of the rotating magnet, that end becomes a north pole, the left end a south pole. Thus, the right-hand pillar and the left-hand end of the rotating magnet, as on Working in Glass 149 the other side the pole of the left-hand pillar and the left- hand end of the rotating magnet, will attract each other, the axle carrying the horizontal magnet revolving from left to right. If the poles of the rotating magnet were unchange- able, the revolution would cease as soon as the revolving magnets were just between the pillars. But at the moment when this position is reached, the springs leave the half- sockets with which they have hitherto been in contact, the current is interrupted, both magnets become demagnetised, and the attraction ceases. Impetus causes the movable magnet to turn a little farther ; whereupon the relations are changed. The circuit is again completed, but the current now circulates round the rotating magnet in the opposite direction, the poles change, and are consequently now repelled by the poles on the pillars which before attracted them. The result is rotation in the same direction as before. As soon as the rotating magnet again comes half- way between the pillars, its poles are again changed, and so the rotation is continued. If the work be carefully done, rapid rotation will be produced, to the great satisfaction of the workman. D. WORKING IN GLASS. We do not propose to make Glass-Work a separate and independent course, but rather to treat it as subsidiary to the other courses we have suggested. We may point out that the work is at once necessary and easy to learn. It enables us to produce a large number of Anschauungsmittel and much apparatus for school instruction, the making of which we should have to renounce if we excluded exer- cises in the simple manipulation of glass. Those who are willing to employ a glass-cutter can, of course, dispense with such exercises ; but as we desire to be of service to those also who wish to be independent of all assistance, we have in the following pages brought together a series 1 50 Manual Training made serviceable to the School of examples of Glass-Work regarded as a complement to previous courses. As, then, our task was to set our young workmen to completing models already made, and not to exhibit in systematic order by means of special objects the various ways of treating glass, we were confronted by a difficulty. "We had to avoid proposing work involving various processes, lest a simple introductory exercise should be found combined with another and far harder one, requiring long practice before it could be done to perfection. We have met the difficulty by arranging the tasks in groups. In each group more than one kind of work is called for; but due care has been taken to present technical difficulties in an ascend- ing series. a. Glass-Cutting, Smoothing Edges, Roughing. 1. Cutting a piece of glass for the apparatus to exhibit the unequal expansion of metals by heat. (See Bench- Work, No. 17; Metal-Work, Nos. 20 and 28.) To reduce as far as possible the friction of the index wire on its support when the metal bars are heated, we cut a strip of glass of the same width as the support, and of suitable length. The glass is fastened on with sealing-wax. 2. Cutting sheets of glass for the two devices to illustrate the refraction of light. (See Bench - Work, Nos. 31a and 31b ; Metal- Work, No. 33.) The shape of the sheets is easily seen in the plates to Bench- Work, Nos.- 31a and 31b. 3. Cutting of two equal mirrors for the corner mirror. (See Cardboard- Work, No. 18.) 4. Cutting of two equal mirrors for the " light echo " described in Cardboard- Work, No 31. The mirrors, having to fit exactly into the supports, must be cut carefully to measure. Working in Glass iSi 5. Cutting of four rectangular mirrors for the "look- ing round the corner" apparatus. (See Cardboard -Work, No. 44.) 6. Cutting of a small rectangular mirror to illustrate the optical law, The angle of reflection of a ray of light is equal to the angle of incidence. (See Cardboard-Work, No. 33.) 7. Cutting of a mirror and two squares of glass, and roughing of the latter — for the camera obscura. (See Cardboard-Work, No. 50.) 8. Cutting of a round sheet of glass for the exhibition of electric attraction and repulsion. (See Cardboard- Work, No. 41.) 9. Cutting of three rectangular and u two round pieces of glass, and roughing of one of the latter — for the kaleido- scope. . (See Cardboard- Work, No. 47.) b. Glass-Boring and Joining, Mounting on Glass. 10. Anschauungsmittel for Solid Geometry. The making of one such model for the proof of the theorems of Solid Geometry is sufficient to show the general method of con- structing them. The model repre- sented by the drawing serves to establish the theorem : — If a straight line stand at right angles to each of two straight lines at the point of their intersection, it shall also be at right angles to the plane which passes through them— that is, to the plane in which they are (Euclid XI. 4). 152 Manual Training made serviceable to the School The plane is represented by the sheet of glass ; the straight line at right angles to it by a piece of iron wire on which, above and below the glass, a small piece of metal is soldered to keep the wire in position. The straight lines lying in the plane are to be cut in thin white cardboard and secured to the glass ; the letters are also cut from cardboard and mounted in their proper places. The lines of construction, AC, AD, AE, drawn from the perpendicular to points in the plane, are represented by pieces of thread or string. The cutting of glass, already practised by the pupil, reappears here ; technically new is the boring of the holes through the glass plate. This is done with a drill, the point of which has been hardened for the purpose, turpentine being dropped on from time to time as one drills. 11. Cementing three glasses in an insulating stool. (See Bench-Work, No. 6.) 12. Covering the Leyden jar with tinfoil both inside and outside. (See Metal-Work, No. 27.) A fairly large glass jar is used. The inside is covered first. (See Weinhold, Vorschule, p. 402.) c. Cutting Glass Tubes into Parts, Springing, Bending, and Drawing out Glass. 13. Glass handle for the electrophorus. (See Metal- Work, No. 25.) The method of dividing a glass tube is as follows : — Scratch one side of the tube at the required point with a triangular file moistened with turpentine ; place both thumbs on the glass opposite to the scratch and break off the piece desired. The sharp edges may be rounded by heating the ends until the glass begins to melt ; the edges will then round themselves. The glass handle thus obtained is puttied into the socket for its reception already soldered on to the cover of the electrophorus. Working in Glass 153 14. Lightning tube. (See Metal-Work, No. 30.) Here we have practice in the dividing of thicker tubes. We file the place where the division is required fairly deep all round, moistening with turpentine as we file ; we then try to break or else spring the tube along the scratched line by means of SprengJcohle. 1 . The sharp edges may in this case be ground smooth on a stone. The spangles of tinfoil are cut with the chisel and placed in a spiral form round the tube from end to end. To attach them, use thin glue. 15. Electroscope. (See Metal- Work, No. 32.) For the foot we use an inverted wine-glass, to which is joined a short-necked flask. The neck of this flask is ground flat and a perforated cork inserted. Into the hole in the cork a piece of glass tubing is fixed, in order that the brass wire which supports the two aluminium leaves may be properly insulated. The brass wire is fixed with putty in the glass tube. 16. Chromic acid element. (See Bench- Work, No. 25 ; Metal- Work, No. 44.) We have here an exercise in springing glass. The process is as follows : — At each side of the place where the glass is to be sprung, bind with string a piece of paper 2 or 3 cm. wide, and rolled round to a thickness of 3 or 4 mm., so as to leave a space of only 2 or 3 mm. free between the rolls, a kind of groove or channel being thus formed. Next take a piece of good string, 2 or 3 mm. thick, tie one end to the screw of the front bench-vice, pass the string once round the glass to be sprung, and tie the other end to a strip of beech wood (50 x 2 or 3 x - 5 cm.), fastened to the bench by means of the back bench-vice. When the 1 " 60 grs. of gum tragacanth are dissolved in sufficient water to make four liquid ounces of mucilage ; 30 grains pulverised gum benzoin are then dissolved in the smallest possible quantity of spirits of wine ; the two solutions are then mixed in a mortar, with enough pulverised and sifted beeohwood charcoal to form a plastic mass." (Trick's Physical Technics, chap, ii., where see more on Glass-Work.) 154 Manual Training made serviceable to the School string is drawn tight, saw quickly to and fro with the glass bottle until the string grows brown. As a rule, the glass of itself springs off smoothly ; or a drop of water on the heated glass will assist the process. The sharp edges are ground on the outside with a slowly turned grindstone, on the inside filed away with a file moistened with oil of turpentine ; or the whole rim may be ground level on a flat slab of sand- stone. The brass rim is cemented outside the rim of the bottle thus sprung. 17. Induction apparatus. (See Metal-Work, No. 31.) The task here is simply to make a glass handle bent at a right angle, and serving to insulate the metal rod. Thus technically the only exercise is in bending glass. When the electric experiment is performed, the longer arm of the glass handle is fastened vertically in a retort- holder (see p. 130), whilst the shorter arm is passed hori- zontally through a hole in a cork ; through a second hole, parallel to the first, the induction apparatus proper is secured, so that the latter is also horizontal during the experiment. 18. Glass arm with hook for insulating. (See Metal- Work, No. 36.) A piece of glass tubing is connected, in the way described under Metal- Work, with a stand to enable us to support pendulums, etc. Before making the connection, the free end is drawn out and bent into the form of a hook. In the drawing the glass arm is the lower one on the right. 19. Glass cup for magnetic needle. (See Metal- Work, No. 23.) The end of a piece of glass tubing is drawn out to a point and closed by melting. The closed conical piece at the end is scratched with the file and broken off, and then heated until sealing-wax melts on it. When the sealing-wax has grown cold, the cup is secured in the bend of the needle, the latter being also heated to the melting-point of the sealing-wax. The magnetic needle can now be balanced on the stand. Working in Glass 155 20. Magic cup. We use two medicine - bottles,' the bottoms of which have been sprung off in the way already described. The two are joined by means of a cork through a hole in which is passed a bent glass tube. The bent part in the upper bottle acts as a siphon, so that when the upper vessel is filled with water until the latter comes above the bend in the tube, the outflow from the lower part of the vessel begins. The exercises which here find application are in springing glass and bending a glass tube. 156 Manual Training made serviceable to the School 21. Fountain. A bottle, the bottom of which has been sprung off, serves as a reservoir. In the neck is inserted a cork, through which the end of a tube bent twice at right angles is passed. The other end of the tube is drawn out until the orifice is very small. Practise in springing glass bending tube, and drawing out. 22. Siphon with suction tube. A combination of two bent glass tubes with an elongated bottle, the bottom of which has been sprung off. The inside of the rim is filed away somewhat, and cork fitted tightly in. This cork has two holes bored through it to receive the two bent tubes, the siphon and the suction pipe. When suction is applied by means of the tube with the upward bend, the neck of the bottle, which is turned downwards, must, of course, be closed with the finger. Practise in dividing and bending tubes, as also in springing glass. 23. Air-sucker. A 'combination of wide and narrower straight and bent glass tubes. The wide glass tube is closed at both ends by means of corks, one of which is pierced once to receive the next widest tube, the other twice to receive a narrower straight tube drawn at the end towards a point, and a U-shaped tube. If we partly fill the U-shaped tube with coloured water, and then blow vigorously into the narrow straight tube, the current of air rushing through the Working in Glass 157 tube second in width carries along with it the air contained in the widest of the tubes. This is rendered apparent by the rising of the coloured water in the arm of the bent tube o»l which leads into the cylinder, the pressure of the air in the other arm forcing the water up. The sucking action of air currents is thus shown. Practise in dividing tubes, draw- ing them out towards a point, and bending them. MORRISON AND GIBB, PRINTERS, EDINBURGH. Newmann's Sloyd and Manual Training Series. JUST ISSUED, A NEW WORK ON CARDBOARD MODELLING FOR SCHOOLS. MANUAL OF CARDBOARD MODELLING, with an Appendix on the Making of Geometrical Models. By W. Heaton, Instructor under the Bradford School Board. The Contents include :— i. A Preface by T. G. Roopee, Esq., M.A. 2. Discussion of the Educational Values of Cardboard work. 3. Notes on the Models. 4. Description of the Materials used and the Method of working. 5. Drawings and Directions for the construction of 82 Models on 67 Plates. 6. A valuable Appendix of Drawings for the use of Children in Upper Classes, and for Teachers who wish to construct a Set of Geometrical Models for Class'Teaching. The Exercises are based on the Stockholm Series of Models. Both Metric and English Measurements are given. Directions for Working face the Drawings. Cr. 4to, 164 pp., bound cloth and lettered, price 5s. 6d. One of Her Majesty's Inspectors writes: — "The Cardboard Sloyd is beautifully got up, and ought to have a success." A Member of the Yorkshire Ladies* Council of Education writes : — " The printing and general get-up is most attractive, and I am sure the book will meet with well-merited success." A Superintendent of Board Schools writes : — " I have gone through the proof of the work. . . . The drawing and instructions are clearly arranged, so that a student has everything necessary before him without cross references. I nave tested the instructions and the working-drawings, and find no inaccuracy." A Manual Instructor writes:— "The instructions given are clear and precise. The working-drawings are well produced ; the giving of both English and Metric measure- ments is a very good feature. With a careful study of the working-drawings and a close attention to the instructions given, any student should be able to make all the models. 1 ' A Teacher of Cardboard Modelling writes :— " I am delighted with both the drawings and letterpress." THE ORGAN OF THE BRITISH SLOYDERS. HAND AND EYE : A Monthly Journal for the Promotion of Kindergarten, Sloyd, and all other forms of Manual Training. The only Magazine in England devoted to Educational Handwork in Schools. The medium of communication between the Members of (1) The Froebel Society ; (2) The Sloyd Association of Great Britain and Ireland; (3) The Northern Counties Sloyd and Educational Handwork Association; (4) The Sloyd Association for Scotland. Published on the 15th of each month, price 3d. ; Annual Subscrip- tion, post free, 3s. 6d. THE LEIPZIC SERIES OF SLOYD DIAGRAMS of the Manual Training School, with Notes and Instructions. Translated by Miss T. B. Bury. The complete Series, Thirteen Parts, net £1. For particulars and price of Single lumbers, see our Catalogue of Tools and Implements for Manual Training. MISS andrHn-s sloyd models. FIFTY DRAWINGS AND DIRECTIONS FOR THE CONSTRUCTION OF SLOYD MODELS (Carpentering). By Miss Andr£n (from Naas). Size, II inches by 9 inches, printed in Two Colours on Stout Cards in Envelopes, arranged to suit English requirements. Net 5s. DIRECTIONS FOR CHIP CARVING. Translated from the German by Miss J. B. Bury. A concise Set of Instructions, with numerous Illustrations of Designs, Tools, and how to hold and use them to obtain the best results. Price 9d. PLEA FOR MANUAL TRAINING. Reprint of the Article which appeared in Nos. and Eye." Price 3d. By T. G. 1 and 2 of R. A "Hand SLOYD AND THE SCIENCE AND ART DEPARTMENT. By A. Hawcridge, Esq., Superintendent of Board Schools, Barrow- in-Furness. Reprinted from "Hand and Eye." Price 2d. THE ART OF MODELLING IN CLAY, clearly and compre- hensively described, with an Appendix giving Instructions for the taking of Plaster Casts and the making of Plaster and Gelatine Moulds, progressively arranged for Kindergarten and Manual Training Classes. By Paul Sturm, Head Teacher at the Leipsic Training College for Manual Training, and Instructor at the Boys' Manual Training Classes. This work forms a clear and concise guide to the proper treatment of the Author's 16 Wall Diagrams for Modelling. Translated by W. J. Field, M.A. Price is. 16 WALL DIAGRAMS, size 24 by 18 ins., for the Systematic Instruction of Clay Modelling, by the same Author as " The Art of Modelling in Clay," each Plate containing numerous Diagrams, printed in black on a white ground. Plates 1 & 2 represent Clay Finger Work. ,, 3 ,, 4 Clay Pulling and Cutting. „ 5 Clay Cutting and Mounting of Clay on a back ground. ,, 6 & 7 Modelling of Constructive Forms with Wooden Modelling Knives. „ 8 Clay Cutting from the Cube. „ 9 do. do. Pyramids derived from the Cube. „ 10 Modelling, more elaborate and artistic development from the cube. TH E 16 PLATES folded in quarto, in strong cover, net 6s. Do. mounted and varnished, 8 boards, front and back, per set, net 10s. 6d. Do. ,, 16 ,, only I on each board, ,, ,, 15s. Plate 11 Modelling of Leaves and Blossom in constructive form. ,, 12 Modelling of Solids in con- structive form. „ 13 Examples of Leaves in con- structive form combined of blossom and fruit. ,, 14 Modelling of Leaf and Fruit. „ 15 Composition. ,, 16 Modelling of Ornaments to a given style. 0. NEWMAM & CO., 84 Newman Street, London, W.