ESSAYS 
 
 ECONOMY OF FUEL, ^c. 
 
PRACTICAL; ifgsn) DESCRIPTIVE 
 
 E S S Y § 
 
 ECONOMY OF FUEL, 
 
 MANAGEMENT OF HEAT. 
 
 ESSAY FIRST, 
 
 In Three Parts. 
 
 PART I. —On the eeeects op heat, means op h 
 
 SDHING IT, FUEL, &C. 
 
 PART 11. — On heating mills, dwelling-houses, , 
 public buildings, by steam. 
 
 PART ill —On drying and heating bt steam. 
 
 BY ROBERTSON BUCHANAN, 
 
 CIVIL ENGINEER. 
 
 BY 7AMSS HSDDERWICK AND CO. 
 
 
FUEFACM, 
 
 The favourable reception given by the 
 public, to an Essa^ on the Warming of Mills 
 and other Buildings hy Steam, which I pub¬ 
 lished in ] 807 *, and the many additional 
 facts on the subject, which, since that 
 
 period, have been determined, and the 
 
 further application of this agent to drying . 
 as well as heating, in various processes in 
 calico-printing and other manufactures, 
 have induced me to think of publishing 
 an enlarged edition of that Essay. 
 
 Reflecting on this subject, and consider¬ 
 ing the materials I had collected on other 
 practical applications of heat, it occurred 
 to me, that I might extend my plan to a , 
 series of Essays on the Economy of Fuel and 
 Management of Heat. 
 
 • For an account of this Pamphlet, see Philosophical Magazine,' 
 Kicholson*s Philosophical Journal, Monthly Magazine, and various- 
 other periodical publications for 1808. 
 
PREFACE. 
 
 iv 
 
 In order to clear the way for these prac¬ 
 tical inquiries, it seemed proper, to give 
 such a view of some of the principal laws 
 which regulate the phenomena of heat, as 
 would, by the help of references, enable the 
 reader the better to imderstand the nature 
 of the facts and observations which would 
 occur in the subsequent parts of these in¬ 
 quiries. To this purpose, I have accord¬ 
 ingly devoted the first part of this Essay. 
 
 Originally, I had no intention to make 
 this introductory part so large as it now 
 is, but in pursuing the subjects which it 
 contains, it appeared to me, that to em¬ 
 brace the objects of my intention, it could 
 not easily be made less. It would, per¬ 
 haps, not conduce to my credit as a writer, 
 were I to tell the .trouble this part has cost 
 me; and, after all my labour, I fear it will 
 be thought by m^y, a mere compilation. 
 But I was more anxious to make a useful 
 than an elegant book, and, therefore, have 
 attempted, in a small compass, to bring 
 into view, all the practical knowledge that 
 I could find on subjects, which I thought 
 
PREFACE. 
 
 could be beneficial to a valuable class of 
 men, whose time being otherwise fully- 
 occupied, have neither leisure, opportunity, 
 nor inclination, to search into numerous, 
 and often costly volumes. If I have sue* 
 ceeded in this intention, my labour has 
 nor been in vain. Nor will general readers, 
 I trust, deem this part altogether unworthy 
 their notice, having endeavoured in it, to 
 give a concise view of the late important 
 discoveries made by Professor Leslie and 
 others, respecting heat. 
 
 The opportunities which I have had, of 
 conversing and corresponding with several 
 of these writers, as well as with other men 
 of science, whose pursuits have been more 
 immediately practical, I have endeavoured 
 to turn to the advantage of the reader. 
 In the “ Additions and Corrections,” I 
 have studied to correct such errors or 
 mistakes as have occurred in the course 
 of this Essay. 
 
 The advantages which this island enjoys 
 
 over other countries, from the abundance 
 
PREFACE. 
 
 of coal, are too well known to require to 
 be here enumerated. But in many other 
 things we labour under much disadvantage, 
 which should stimulate us to cherish this 
 superiority which we enjoy over the nations 
 on the Continent of Europe. The economy 
 of fuel becomes a subject of increasing 
 importance, from the increasing price of 
 labour, which would require exertion to 
 counteract its effects on our commerce and 
 manufactures. Every attempt, therefore, 
 to save fuel, merits attention; and the 
 subject opens a wide and important field 
 for investigation. 
 
 It is not the saving only of fuel which 
 merits attention, but its safe, eas^, and 
 healthful application to the various pur¬ 
 poses of life. 
 
 The recent destruction by fire, of St, 
 James’s Palace, and of the two largest 
 Theatres in the kingdom, has directed 
 much of the public attention to the ren¬ 
 dering of buildings less subject to so 
 dreadful a calamity. In this important 
 
PREFACE. 
 
 vii 
 
 respect, no means of heating buildings has 
 yet been devised^ so good as that by steam, 
 and from its novelty, none is yet so par¬ 
 tially known or understood. I have, there¬ 
 fore, been induced to make it the princi¬ 
 pal subject of this Essay. 
 
 •It consists of Three Parts, the first of 
 these I have already mentioned. The 
 Second Part relates to the application of 
 steam to the heating of buildings of vari¬ 
 ous descriptions, such as dwelling-houses, 
 manufactories, and public buildings. The 
 Third Part treats of the application of this 
 agent to drying of goods,, as well as to 
 further matters relative to, heating. Its 
 excellent effect in preserving brilliancy of 
 colour, in drying goods, is there proved 
 by strong facts;—a consideration of much 
 importance in many of our manufactures. 
 
 I must crave the indulgence of the pub¬ 
 lic, for any want of unity, and other im¬ 
 perfections, which will too readily appear 
 in the whole of this Essay. I have to 
 plead, that it was written at many differ- 
 
PREFACE. 
 
 viii 
 
 ent and distant intervals, occasioned by 
 interruptions from professional engage¬ 
 ments, as well as from ocher and more 
 irksome causes, witli a detail of which I 
 shall not trouble the reader. 
 
 With regatd to the subject of heating 
 by steam, I beg leave here further to re¬ 
 peat the Preface to the Publication to which 
 allusion is made at the beginning of this 
 introduction. 
 
 “ In a country like Britain, where man¬ 
 ufactures are more generally collected and 
 combined in large estabhshments, than 
 dispersed through individual dwellings; 
 the production and dlffiision of the warmth 
 necessary for the health and comfort of 
 the workmen, as well as for the prosecu¬ 
 tion of the different processes, become 
 objects of the first national importance. 
 
 “ The excessive expense of insurance, 
 arising from the combustible nature of the 
 materials of the cotton manufacture in par¬ 
 ticular; the great difficulty of retrieving the 
 
PR-FFACE. 
 
 ix 
 
 injury resulting to a well established busi¬ 
 ness, from the accidental destruction of 
 machinery; and the frequent alarms from 
 fire, in our powder-mills, arsenals, and 
 dock-yards, furnish the strongest economi¬ 
 cal, as well as political recommendations, 
 for the more general employment of steam 
 for the purpose of warming buildings. 
 
 “ The very limited degree in which 
 steam has yet been applied to this pur¬ 
 pose, might surprise us, did we not recol¬ 
 lect, that the steam-engine itself, although 
 known, perhaps, even before the time of 
 the celebrated Marquis of Worcester, 
 has only, within a very few years, by the 
 ingenious improvements of Mr. Watt, 
 been extensively introduced. The fre¬ 
 quent and various use of steam; to which 
 Mr. Watt’s improvements have given 
 rise, in different departments of manufac¬ 
 ture, have furnished accidental results of 
 great value, which are frequently little 
 known to the merely scientific inquirer. 
 
X PREFACE, 
 
 “ The observations -which the Author 
 has been enabled to make, on various con¬ 
 trivances throughout the kingdom, for 
 heating by steam, modified by his own 
 experience, have led him to believe, that 
 the following remarks on this important 
 subject, would not be altogether undeserv¬ 
 ing the notice of the public. 
 
 “ He, however, lays no claim to origin¬ 
 ality, nor does he pretend to give informa¬ 
 tion to men of science, his object is merely 
 to make such a collection of facts, as may 
 be useful to those who wish to put in 
 practice the warming of buildings by 
 
 “ In making this collection, he has been 
 much indebted to the assistance of some 
 friends, without the aid of whose ingenu¬ 
 ity and experience, his headers would have 
 had still more reason to lament its defi¬ 
 ciency. 
 
 “ Those who are most qualified to esti¬ 
 mate the importance of such investigation. 
 
PREFACE. 
 
 xi 
 
 can best appreciate their difficulty, and 
 will, most readily and candidly, pardon 
 the unavoidable imperfection of this at-‘ 
 tempt; the chief object of which, is less to 
 satisfy curiosity, than to direct the atten¬ 
 tion of the public, to the farther prosecu- • 
 tion of an inquiry, not less curious than 
 useful, ” 
 
 I shall now proceed to give an account 
 of the origin and progress of this applica¬ 
 tion of steam. 
 
 An Account of the Origin and Progress of the 
 Application of Steam, to the purpose of Heat¬ 
 ing Buildings. 
 
 In the Philosophical Transactions for the 
 year 1745, Colonel William Cook suggests 
 the idea of warming rooms by steam. But 
 it does not appear that he ever attempted 
 to reduce it to practice. And although 
 Count Rumford, in the third number of 
 the Journals of the Royal Institution, men¬ 
 tions, that “ this scheme has frequently 
 “ been put in practice with success, in this 
 “ country, as we’.l as on the Continent,” 
 b 
 
PREFACE. 
 
 Sll 
 
 I have not been able to learn, that any 
 thing of importance was done, previously 
 to the use of steam in warming cotton- 
 mills *. 
 
 • It is natural to suppose, that Mr. Watt’s 
 attention to other applications of steam, 
 would lead him to the consideration of the 
 particular subject of heating buildings. 
 Such was indeed the case. The period at 
 which he used steam for warming the 
 room in which he commonly wrote, was 
 1784, or 5, probably the winter between 
 these two years. The room was about 18 
 feet long, by 14 feet wide, and 8| feet 
 high; and the apparatus consisted of a 
 box, or heater, made of two side-plates of 
 tinned iron, about Si feet long, by 2i wide, 
 kept at the distance of an inch asunder, by 
 means of stays, and joined round the edges 
 by other tin-plates. This box was placed 
 upon its edge, near the floor of the room, 
 and furnished with a cock to let out the 
 air, and witli a pipe, proceeding from its 
 
 A patent for heating by steam was granted to John Hoyle, dated 7tSi 
 Inly, 1791; and to Joseph Green, dated 9th December, 179S. 
 
PREFACE. 
 
 xiii 
 
 lower edge to a boiler in an under apart¬ 
 ment, which pipe served to convey the 
 steam, and return the water. The effect 
 produced by this apparatus, was less than 
 Mr. Watt had calculated, which, perhaps, 
 may now be explained by Professor Leslie’s 
 experiments on the heat transmitted by 
 polished surfaces. 
 
 Mr. Boulton heated a room in his man¬ 
 ufactory by steam, soon after this time; 
 but the very infirm state of his health at 
 this moment, prevents me from obtaining 
 accurate information concerning it f. He, 
 however, heated his bath by steam, a few 
 years later, I believe about the year 1789, 
 which he continued to do from that period, 
 until a very short time ago. 
 
 Towards the end of the year 1794, he 
 assisted the late Marquis of Lansdown, to 
 improve an apparatus, erected by a Mr. 
 Green, for warming his library, by means 
 of air heated by steam; but the use of it 
 was afterwards abandoned, owing, I be- 
 
 • This wa# written previously to Mr, Boulton’s deatli. 
 
XIV 
 
 PREFACE. 
 
 lieve, to some defect in the pipes or joints. 
 About a twelvemonth later, in the winter 
 of 1795-6, Mr. Boulton directed the erec¬ 
 tion of a similar apparatus, for his friend 
 Dr. Withering’s library, which, in point 
 of heating, answered perfectly; but the 
 pipes being made of copper, and soft sol¬ 
 dered in some places, the smell of the 
 solder was rather unpleasant to the Doctor, 
 who was then in an infirm state of health 
 with diseased lungs. The apparatus was, 
 in consequence, removed to Soho, where 
 Mr. Boulton proposed erecting it in his 
 own house, in which he was making al¬ 
 terations about this time, and had it in 
 view, to heat every room in the house by 
 steam. A boiler was put up for that pur¬ 
 pose, in one of the cellars, but some cir¬ 
 cumstances occurred, to prevent his con¬ 
 tinuing the plan. The subject, however, 
 underwent frequent discussions, and the 
 different modes of effecting it, were amply 
 considered by Messrs. Boulton and Watt, 
 as was known to many of their friends, 
 no secret having been made, either of cal¬ 
 culations of surface, or of the modes of 
 applying them. 
 
PREFACE. 
 
 XV 
 
 About the end of the year 1799, Mr, 
 Lee of Manchester, having a large increase 
 of his cotton-mill in vievf, consulted with 
 Messrs. Boulton and Watt, relative to the 
 best mode of heating it by steam; and, in 
 the course of the subsequent year, he 
 erected his present- apparatus of cast-iron . 
 pipes^ acting also as supports to the floor, 
 which answered perfectly, and was, both 
 in point of the materials used, and of the 
 construction adopted, as far as I know, the 
 first of the kind. I may add, that though 
 the construction has been frequently imi¬ 
 tated by others, I have never heard of any 
 material improvement having been made 
 upon it. From that period, many appara¬ 
 tus v/ere constructed by them, in some of 
 which, applied to old buildings, the pipes 
 were conducted horizontally through the 
 rooms, with other variations of little im¬ 
 portance. 
 
 It may not be improper here to add, the 
 vats, &c, of the dye-house of Messrs. 
 Wormauld & Gott, of Leeds, were heated 
 by steam, imder the direction of Messrs, 
 
XVI 
 
 PREFACE. 
 
 Boulton & Watt, in the year IISO. The 
 apparatus was planned in August of that 
 year, and set to work either in the course 
 of it, or early in the succeeding one. The 
 history of that establishment has been 
 very incorrectly given, in the Journals of 
 the Royal Institution, for 1801. 
 
 The merit of the first application of 
 steam, to the heating of buildings in Scot¬ 
 land, belongs to Mr. Snodgrass. He in¬ 
 troduced it * into the cotton-work, which 
 Messrs. Dale & M‘Intosh established on 
 the banks of the Spey f. 
 
 Soon after this period, Mr. Houldsworth 
 of Glasgow, used it with great success. 
 His example has been followed by several 
 other respectable cotton-spinners. 
 
 Steam was. soon afterwards applied to 
 warm buildings, appropriated to the pur¬ 
 poses of calico-printing. Mr. Richard 
 
 ledge of -what had been done in England. 
 
 t See Philosophical M^azinefor March, 1807. 
 
PREFACE. 
 
 xvii 
 
 Gillespie, in his calico-works at Anderston, 
 was induced very early to use it in his 
 warehouse for finished goods, and has 
 since been gradually extending it through 
 other parts of his works*. It has also 
 been adopted by some calico-printers in 
 England. 
 
 Messrs. W. Stirling & Sons are at present 
 getting steam apparatus fitted up for their 
 extensive calico-printing works at Cordale. 
 
 In Ireland, Messrs. On* have introduced 
 'it at their works, at Stratford upon Slainy. 
 It is also gradually finding its way into 
 the cotton-mills in that kingdom. 
 
 Messrs. Oakley & Co. cabinet-makers, 
 London, have heated their premises by 
 steam; and Messrs. James Ballantyne & 
 Co. have applied it to the heating of their 
 printing-office in Edinburgh. 
 
 • In the introduction to the Third Part of this Essay, there it a 
 Harrative respecting the application of steam to the puipose of drying. 
 
TABLE OF CONTENTS. 
 
 iii Section H.—Of the Propor- 
 
l^att ifitst 
 
 EFFECTS OF HEAT, 
 
 MEANS OF MEASURING IT, 
 
 FUEL, &c. 
 
 SECTION 1. 
 
 1. Before proceeding to the more prac¬ 
 tical parts of the economy of fuel, in order 
 to establish our inquiries on solid grounds, 
 it will be proper here, to take a view of 
 some of the principal laws which regulate 
 the phenomena of heat. 
 
 A 
 
EFFECTS OF HEAT. 
 
 The most eminent philosophers of the 
 present age, are not yet agreed respecting 
 the nature of heat, nor cjm any of them yet 
 give to a plain inquirer a satisfactory an¬ 
 swer to this simple question. What is heat? 
 While some consider it as merely a state or 
 condition of which all bodies are susceptible; 
 others conceive that heat is a material sub¬ 
 stance —an elastic fluid, extremely subtile 
 and active. 
 
 I shall not take up the reader’s time, 
 
 by attempting to inyestigate the merits of 
 
 those opinions, since it is of no consequence 
 to our present purpose, which of the parties 
 is in the right. 
 
 But although we may not be able to 
 comprehend the nature of heat, we may 
 arrive at the knowledge of many of its 
 ^ects^ and so classify and arrange these, 
 as to adapt them to many useful purposes 
 in common life. 
 
EFFECTS OF HEAT. 
 
 OF HEAT. 
 
 2. The term heat, as used in common 
 language, is ambiguous, being applied to 
 express either a certain sensation, or the ex¬ 
 ternal cause which excites that sensation. 
 It is in this last sense only, that we are at 
 present to consider it; and to this meaning 
 of the term heat, the authors of the New 
 French Chemical Nomenclature, have given 
 the definite name of caloric*. 
 
 3. “ When all surrounding bodies are of 
 one temperature, then the heat attached to 
 them is in a quiescent state; the absolute 
 quantities of heat in any two bodies, in 
 this case, are not equal, whether we take 
 
 * “ The term ea/oric has been adopted in the New Nomenclature, to 
 avoid that ambigult7 and misconception which might, it is said, arise 
 from employing the same term to express a substance, and the sensa¬ 
 tion produced by the action of that substance. By the same mode of 
 reasoning, all the suhstanitves should be changed, in any language that 
 has similar verbs. But suppose the argument, for change, in the' pre¬ 
 sent instance, to have full force in some languages, it has little or none 
 with regard to the English, which employs the word ’warmth to express 
 the sensation occasioned by heat. I shall, however, use the terms heat 
 and caloric In^fferently.” 
 
 Ttlloeh's Phihsojihical Magazine, vol. 8. p, 71. 
 
4 
 
 EFFECTS OF HEAT. 
 
 the bodies of equal weights, or of equal 
 bulks. Each kind of matter has its peculiar 
 affinity for heat, by which it requires a 
 certain portion of the fluid, in order to be 
 in equilibrium with other bodies at a cer¬ 
 tain temperature Thus, when the heat 
 of a room is increased, the various bodies 
 
 cont^ed in it will attract and retain dif¬ 
 ferent quantities of heat This property 
 seems to indicate the materiality of caloric, 
 since, though in a quiescent state, it exists 
 in bodies in difierent proportions, modified 
 neither by their density nor form, but by 
 some innate and peculiar force of attraction, 
 resembling chemical affinity. To express 
 this faculty, the term capacity for heat was 
 invented, and employed by the British 
 philosophers; the name specific caloric being 
 used for the same purpose, by those on the 
 Continent. 
 
 However various the capacities of bodies 
 for heat may be, yet, in consequence of the 
 perfect elasticity of this power, it will 
 speedily acquire the same tension in them 
 
 ♦ Paltoa’s Chemical Philosophy, p. 2. 
 
EFFECTS OF HEAT. 
 
 5 
 
 all; or, like a number of tubes of different 
 magnitudes, but narrow apertures, plunged 
 into the same vessel of water, it will soon 
 stand in each at the same height or level, 
 though the absolute quantity in them be 
 very different. Now, it must evidently be 
 a desirable object, vsdth the philosopher, 
 to obtain some means of estimating this 
 tension, or height, or degree of tempera¬ 
 ture, as it is technically termed. 
 
 Of Thermometers. 
 
 4. The thermometer was invented early 
 in the 17th century, but, like many other 
 useful contrivances, its real author has 
 never been ascertained. The first form of 
 this instrument was the air thermometer. 
 The air was confined in a tube by means 
 of some coloured liquor, and the liquor 
 rose or fell in the tube, accordingly as the 
 air became expanded or condensed. It was 
 found, however, to be very defective. The 
 expansion of spirit of wine was next used, 
 but still thermometers had a great defect; 
 the scale did not commence at any fixed 
 
EFFECTS OF HEAT. 
 
 point. While they laboured under this 
 disadvantage, they could not be of general 
 
 The subject which next drew the atten¬ 
 tion of philosophers, was to obtain some 
 fxed unalterable points., by which a deter¬ 
 minate scale might be formed, so that all 
 thermometers might be accurately adjusted 
 to one standard. These important points, 
 on which the accuracy and value of the 
 thermometer depends, although previotisly 
 discovered by Dr. Hooke seem first to 
 have been practically applied by Sir Isaac 
 Newton. He chose, as fixed, those points 
 at which water freezes and boils; the very 
 points which'the experiments of succeeding 
 philosophers have determined to be the 
 most fixed and convenient. Sir Isaac 
 Nevrton used lintseed oil in his thermom¬ 
 eter, which was constructed in 1701. 
 
 5. Oil, however, was found to have 
 many imperfections. At length a different 
 
 • Dr. Robert Hooke discovered the permanency of the temperature 
 of freezing in 1664, and of boiling water in 1684. 
 
EFFECTS OF HEAT. 
 
 7 
 
 fluid was proposed, by which thermometers 
 could be made free from most of the defects 
 
 alluded to. This fluid was mercury, and 
 
 seems first to have occurred to Dr. Halley, 
 about the end of the 17th century, but was 
 not adopted by him, on accotmt of its hav¬ 
 ing less expansibility than the other fluids 
 then in use for thermometers. The honour 
 of this invention is commonly given to 
 Fahrenheit of Amsterdam, who presented 
 an account of it to the Royal Society of 
 London, in 1724. 
 
 6. Fahrenheit’s thermometer consists of 
 a slender cylindrical tube, and a small bulb. 
 To the side of the tube is annexed a scale 
 which Fahrenheit divided into 600 equal 
 parts, beginning with that of the severe 
 cold which he had observed in Iceland, in 
 1709, or that produced by surrounding 
 the bulb of the thermometer with a mix¬ 
 ture of snow with sal-tamoniac, or with 
 sea-salt. The point at which mercury be¬ 
 gins to boil, he made the other limit of his 
 scale. By trials, he found that the mercury 
 stood at 32® on his scale, when snow or 
 
8 
 
 EFFECTS OF HEAT. 
 
 ice just begins to thaw, which was, there¬ 
 fore, called the freeing point. When the 
 tube was immersed in boiling water, the 
 mercury rose to 212°, which was, therefore, 
 denominated the boiling point, and is just 
 180° above the freezing point. 
 
 7. But the present method of making 
 these thermometers, is to immerse the bulb 
 in melting ice or snow, and mark the place 
 where the mercury stands with the num¬ 
 ber 32°, then immerge it in boiling water, 
 and again mark the place where the mer¬ 
 cury Stands in the tube, which indicates 
 the position of 212°. Dividing, therefore, 
 the intermediate space into 180 equal parts, 
 will give the"scale of the thermometer, and 
 which may afterwards be continued upward 
 and downward at pleasure. 
 
 8. These fixed points are now universally 
 chosen for adjusting thermometers to a 
 scale, but it is well known that the point 
 at which water boils is not invariable. It 
 varies some degrees, according to the weight 
 and temperature of the atmosphere. 
 
EFFECTS OF HEAT. 
 
 9. In order, therefore, to insure uni¬ 
 formity in the construction of thermom¬ 
 eters, it is now agreed, that the bulb 
 of the tube be suspended in the steana 
 when the water boils violently, the barom¬ 
 eter* standing at 30 English inches, which 
 is its mean height’round London, and the 
 temperature of the atmosphere 55° f. 
 
 , 10. Fahrenheit’s thermometer, ds now 
 universally used in ■ this kingdom. See 
 
 The centigrade thermometer, or that of 
 France, since the Revolution, places Zero, 
 or 0, at the freezing point, and divides the 
 range between it and the boiling point 
 into 100°. This has been long used in 
 
 • I suppose the reader to be -previously acquainted with the doctrine 
 of the preuurt of the atmosphere^ and the construction of the barometer. 
 If not, as it is necessary to the right understanding of the following 
 parts of tWs Essay, I beg leave to refer to Gregory’s Mechanics, vol. 2. 
 p. 112, or almost any other of the elementary Treatises on Natural 
 Philosophy. 
 
 f See the Report of the Committee for adjusting Thermometers, 
 Philosophical Transactions, vol. LXVII. 
 
 B 
 
10 EFFECTS OF HEAT. 
 
 Sweden, under the title of Celsius’s ther¬ 
 mometer. See Fig. 2. 
 
 11. Reaumur’s thermometer, which .was 
 formerly used in France, divides the space 
 between the freezing and the boiling of 
 water, into 80 degrees, and places the 
 Zero at the freeedng point. Fig. 2. 
 
 12. Mr. Mtirray has suggested a scale 
 which, he conceives, would be much more 
 convenient than that of Fahrenheit. - He 
 uses, as fixed points, those of the freezing 
 and boiling of mercury, and divides the 
 intermediate space into one thousand 
 parts, or degrees See Fig. 3. 
 
 13. The expansion which is observed in 
 a mercurial thermometer, is, in reality, 
 only the difference of expansions of mer¬ 
 cury and of glass. 
 
 14. It has long been supposed, that the 
 
 equal divisions on Fahrenheit’s scale, did 
 
 * Murray’* Chemistry, voL i. p. 153. 
 
effects of heat. 
 
 11 
 
 not point out the real equal increments 
 (or degrees of equal increase) of tempera¬ 
 ture. This circumstance was not over¬ 
 looked by Dr. Black, who illustrates it in 
 the following manner: “ If a string be 
 stretched, by suspending a moderate 
 weight to it, and we add one pound to 
 that weight, we shall make it a little 
 longerj but by adding a second pound, 
 we shall not add as much more to the 
 length of the string as the first poimd 
 added, nor will a third pound produce so 
 much effect as the second pound. In like 
 rhanner, we can imagine, that when a 
 thermometer receives a series of equal ad¬ 
 ditions to its heat, these may not produce 
 equal increments of expansion; and, there¬ 
 fore, that equal increments of expansion 
 may require for their production, incre¬ 
 ments of heat, very unequal among them¬ 
 selves. This question has been over¬ 
 looked, or little attended to, by some of 
 the principal writers on thermometers. It 
 does not appear to have occurred to Dr. 
 Boerhaave, and Dr. Martin gives very little 
 attention to it. I began to attend to it. 
 
12 
 
 EFFECTS OF HEAT. 
 
 and made an experiment to decide it in 
 the year 1760, and did not then know that 
 others had thought of it; but I soon 
 learned, that Boyle, Renaldini of Padua, 
 Wolfius, Dr. Halley, Sir Isaac Newton, 
 and Dr. Brook Taylor, had severally given 
 their opinions of doubts concerning this 
 question 
 
 The result, however, of Dr. Black’s 
 inquiry was, “ that equal additions, or 
 abstractions of heat, produced equal varia¬ 
 tions of bulk in the liq^uor of the thermom¬ 
 eters employed by him, and, therefore, 
 that the scale of expansion was also a scale 
 of heat 'f, or, at least, that there was but 
 “ a little ''deviation from the. exact propor- 
 tion” 
 
 “ M. De Luc,” says Mr. Dalton, “ found 
 that in mi^g equal weights of water, at 
 the freezing and boiling temperatures, 32* 
 and 212°, the mixture indicated nearly 
 
 Vide Black’s Lectures, 
 
 I Black’s Lectures, toI. i. Preface, p.: 
 
effects of heat. 
 
 13 
 
 119° of Fahrenheit’s thermometer, but the 
 numerical mean, or average, is 122°. If 
 he had mixed equal bulks' of water at 32* 
 and 212°, he would have found a mean of 
 115V’ . 
 
 15. “ It is not improbable, that the true 
 mean temperature between 32° and 212°, 
 may be as low as 110° of Fahrenheit*”. 
 
 ■ We are indebted to Mr. Dalton, for 
 farther investigating this intricate subject, 
 and he has formed a scale which, he con¬ 
 ceives, will correspond with the increments 
 of heat; and, as this is an important part 
 of our subject, I shall here give some 
 extracts with relation to it, from his late 
 valuable publication. 
 
 16. “ In the present imperfect mode of 
 estimating temperature, the equable expan¬ 
 sion of mercury is adopted as a scale for 
 its measure. - This cannot be correct, for 
 two reasons: 1st, The mixture of water of 
 
14 EFFECTS OF HEAT. 
 
 difierent temperatures, is always helow the 
 mean by the mercurial thermometer; for 
 instance, water of 32° and 212° being 
 mixed, gives 119° by the thermometer; 
 whereas, it appears, from the preceding 
 remarks, that the temperature of such 
 mixture ought to be. found above the 
 mean 120°. 2d, Mercury appears, by the 
 most recent experiments, to expand by the 
 same law as water, namely, as the square 
 of the temperature from the point of 
 greatest density. The apparently equal ex¬ 
 pansion of mercury,- arises from our taking 
 a small portion of the scale of expansion, 
 and that at some distance from the freez¬ 
 ing point of the liquid. 
 
 17. “ From what has been remarked, it 
 appears, that we have not yet any mode, 
 easily practicable, for ascertaining what is 
 the true mean between any two tempera¬ 
 tures, as those of freezing and boiling 
 water; nor any thermometer which can 
 be considered as approximating nearly to 
 accuracy. 
 
EFFECTS OF HEAT. 
 
 15 
 
 18. Heat is a very important agent in 
 nature; it cannot be doubted, that so active 
 a principle must be subject to general laws. 
 If the phenomena indicate otherwise, it is 
 because we do not take a sufficiently com¬ 
 prehensive view of them. Philosophers 
 have sought, but in vain, for a body that 
 should expand uniformly, or in arithmeti¬ 
 cal progression, by equal increments of 
 heat; liquids have been tried, and found 
 to expand unequally; all of them expand¬ 
 ing more in the higher temperatures than 
 in the lower, but no two exactly alike. 
 Mercury has appeared to have the least 
 variation, or approaches nearest to uniform 
 expansion, and on that and other accounts, 
 has been generally preferred, in the con¬ 
 struction of therrhometers. 
 
 19, “ Some time ago, it occurred to 
 me as probable, that water and mercury, 
 notwithstanding their apparent diversity, 
 actually expand by the same law, and 
 that the quantity of expansion is as the 
 square of the temperature, from their re¬ 
 spective freezing points. Water very 
 
16 
 
 EFFECTS OF HEAT. 
 
 nearly accords with this law, according to 
 the present scale of temperature, and the 
 little deviation observable, is exactly of 
 the sort that ought to. exist, from the 
 knovm error of the equal division of the 
 mercurial scale. By prosecuting this in¬ 
 quiry, I found that the mercurial and 
 water .scales, divided according to the 
 principle just mentioned, would perfectly 
 accord, as far -as they were comparable, 
 and that the law will probably extend to 
 all other pure liquids, but not to hetero¬ 
 genous compounds, as liquid solutions of 
 salts 
 
 20. “ However, it now appears, that the 
 force of steam, in contact with water, in¬ 
 creases ACCURATELY in geometrical pro¬ 
 gression, to equal increments of tempera¬ 
 ture, provided those increments are mea¬ 
 sured by a thermometer of water or mer¬ 
 cury, the scales of which are divided 
 according to the above-mentioned law. 
 
 * Dalton’s < 
 
 nical Philosophy, p. 8—11. 
 
EFFECTS OF HEAT. 
 
 17 
 
 21. “ The force of steam having been 
 found to vary by the above law, it was 
 natural to expect that of air to do the same; 
 for, air (meaning any permanently elastic 
 fluid) and steam are essentially the same, 
 differing only in certain modifications. 
 Accordingly, it was found upon trial, that 
 air expands in geometrical progression to 
 equal increments of temperature, measured 
 as above. Steam detached from water, by 
 which it is rendered incapable of increase 
 or diminution in quantity, was found, by 
 Gay Lussac, to have the same quantity of 
 expansion as the permanently elastic fluids. 
 I had formerly conjectured that air expands 
 as the cube of the temperature from absolute 
 privation, as hinted in the essay above- 
 mentioned; but I am now obliged to 
 abandon that conjecture. 
 
 22. “ The union of so many analogies, 
 in favour of the preceding hypothesis of 
 temperature, is almost sufficient to establish 
 it; but one remarkable trait of temperature, 
 derived from experiments on the heating 
 and cooling of bodies, which does not ac- 
 
 C 
 
18 
 
 EFFECTS OF HEAT. 
 
 cord with the' received scale, and which, 
 nevertheless, claims special consideration, 
 is, that a body in cooling loses heat in propor¬ 
 tion to its excess of temperature above that of 
 the cooling medium-, or that the temperature 
 descends in geometrical progression in 
 equai moments of time. Thus, if a body 
 were 1.000° above the medium; the times 
 in cooling from 1000° to 100, from 100 
 to 10, and from 10 to 1°, ought all to be 
 the same. This, though nearly, is not 
 accurately true, if we adopt the common 
 scale, as is well known; the times in the 
 lower intervals of temperature are found 
 longer than in the upper; but the new 
 scale proposed, by shortening the lower 
 degrees, and lengthening the higher, is 
 found perfectly according to this remark¬ 
 able law of heat. 
 
 23. “ Temperamre then will be foimd 
 to have four most remarkable analogies 
 to support it. 
 
 “ 1st All pure homogenous liqtiids, as 
 water and mercury, expand from the point 
 of their congelation, or greatest density, a 
 
EFFECTS OF HEAT, 19 
 
 quantity always as the square of the tem¬ 
 perature from that point. 
 
 “ 2, The force of steam from pure 
 liquids, as water, ether, &c. constitutes a 
 geometrical progression to increments of 
 temperature in arithmetical progression. 
 
 “ 3, The expansion of permanent elastic 
 fluids, is in geometrical progression to 
 equal increments of temperature. 
 
 “ 4. The refrigeration of bodies is in 
 geometrical progression in equal incre¬ 
 ments of time. 
 
 “ A mercurial thermometer graduated 
 according to this principle, will differ from 
 the ordinary one with equidifferential 
 scale, by having its lower degrees smaller, 
 and the upper ones larger; the mean be¬ 
 tween freezing and boiling water, or 122° 
 oh the new scale, will be found about 110° 
 on the old one.—The following table ex¬ 
 hibits the numerical calculations illustra¬ 
 tive of the principles inculcated above 
 
 • Dalton’s Chemical PhUosophy, p. 11—14. 
 
EFFECTS OF HEAT. 
 
 21 
 
 Explanation of the Table. 
 
 25. Column I. contains the degrees of 
 temperature, of which there are supposed 
 to be 180, between freezing and boiling 
 water, according to Fahrenheit. By com¬ 
 paring this column with the II. the cor¬ 
 respondences of Mr. Dalton’s new scale and 
 the common one are perceived; the greatest 
 difference between 32° and 212°, is ob¬ 
 servable at 122° of tlie new scale, which 
 agrees with 110° of the old, the difference 
 being 12°; but below 32° and above 212’ 
 the differences become more remarkable. 
 
 The first number in the column, —175' 
 denotes the point at which mercury freezes, 
 hitherto marked —40°. 
 
 By viewing column II. along with the I. 
 the quantity of the supposed error in the 
 common scale may be perceived; and any 
 observations on the old thermometer may 
 ' be reduced to the new. See Fig. 1. 
 
 Column II. contains the common Fah¬ 
 renheit’s scale. 
 
22 
 
 EFFECTS OF HEAT. 
 
 Column III. contains a series of numbers 
 in geometrical progression, representing 
 the expansion of air, or elastic fluids. 
 
 Column IV. contains the squares of the 
 arithmetical series, 1,2,3, &c. representing 
 the expansion of water by equal intervals 
 of temperature. 
 
 Column V. contains the force of aque¬ 
 ous vapours in contact with water, ex¬ 
 pressed in inches of mercury, at the re¬ 
 spective temperatures. 
 
 26. On the construction hitherto de¬ 
 scribed, the thermometer is necessarily 
 very limited in its application. When 
 made with alcohol, or spirit of wine, it 
 may be said, indeed, to measure the greatest 
 degrees of cold witli which we are ac¬ 
 quainted; but even the mercurial ther¬ 
 mometer measures no higher than 400 
 degrees above boiling water, by Fahren¬ 
 heit’s scale, or about 250 degrees by Mr. 
 Dalton’s new scale, at which temperature 
 mercmy boils. This comes short of red 
 
EFFECTS OF HEAT. 
 
 23 
 
 heat, and is far below the highest attain¬ 
 able temperature. To supply this defi¬ 
 ciency, and to measure high temperatures, 
 various methods have been proposed. The 
 instruments thus applied to measure high 
 temperatures, are usually n’surndpi/rometers. 
 That which has come into most general 
 use, was invented by the late Mr. Wedge- 
 wood; but even on this instrument there 
 is still great room for improvement. 
 
 Wedgewood’s pyrometer consists of cy¬ 
 lindrical pieces of clay, composed in the 
 manner of earthen ware, and slightly 
 baked. When used, one of them is ex¬ 
 posed in a crucible to the heat proposed 
 to be measured, and after cooling, it is 
 found to be contracted in proportion to 
 the heat previously sustained; the quantity 
 of contraction being measured, indicates 
 the temperature. 
 
 The utility of this instrument, it was 
 obvious, could be increased, by connecting 
 it with the mercurial thermometer, and by 
 ascertaining the proportional degrees of 
 
24 
 
 EFFECTS OF HEAT. 
 
 each. This was accordingly done by Mr. 
 Wedgewood. Its scale commences at red 
 heat, fully visible in day-light. Its whole 
 range , is divided into 240 equal degrees, 
 each of which is calculated to be equal to 
 130° of Fahrenheit. The lowest, or 0, is 
 fotmd about 107*7° of Fahrenheit (suppos¬ 
 ing the common scale continued above 
 boiling mercmy), and the highest 32277°. 
 
 In Fig. 4, is given a diagram, which . 
 may serve farther to illustrate the con¬ 
 nection between the mercurial thermom¬ 
 eter, and that of Mr. Wedgewood. 
 
 The following table exhibits some of 
 the more remarkable temperatures in the 
 whole range of Reaumtu', Fahrenheit, Cel¬ 
 sius, and Wedgewood’s thermometers. 
 
EFFECTS OF'HEAT. 
 
 25 
 
 27. TABLE of the Degrees of different Ther¬ 
 mometers omitting Fractions, at which some 
 remarhahle Chemical Phenomena occiir. 
 
 
 Greatest artificial cold ob¬ 
 served, produced by Mr. 
 Walker. 
 
 Nitric acid freezes, Fourcroy. 
 Cold observed at Hudson’s 
 Bay, M‘Nah. 
 
 Ether freezes. 
 
 Ammonia exists in 
 
 Mercury freezes. 
 
 SulphuricacidfreezeSjrAomMB 
 
 " ilphurous acid liquid, Monge. 
 )ld observed at Glasgow on 
 
 the surface of snow, 1780. 
 Acetous acid freezes. 
 
 Cold observed at Glaseow, 
 1780. 
 
 Two parts of alcohol and one 
 
 Cold observed on the snow at 
 Kendal, 1791. 
 
 Brandy freezes. 
 
 Cold, produced by mixing 
 
 equal parts of snow and 
 muriate of soda. 
 
 Oil of turpentine freezes. 
 Margueron did not freeze 
 at —18 Morelli. 
 
 Strong wines freeze. 
 
 Fluoric acid freezes, Priestly. 
 Oil of bergamot and cin¬ 
 namon freezes, Marg. 
 Human blood freezes. 
 
 Vinegar freezes’ ' 
 
 Milk freezes. 
 
 Oxymuriatic acid melts, Thm- 
 
 son. Water freezes. 
 
26 
 
 EFFECTS OF HEAT, 
 
 ) Olive oil freezes. 
 
 Heat of hedgehogs and mar¬ 
 mots in a torpid state. 
 
 Oxymuriatic acid boils, Tham- 
 son. Equal parts of phos¬ 
 phorus and sulphur melt, 
 Pelldhr. 
 
 Phosphorus bums slowly. 
 
 Sulphuric acid, Sp. gr. 1.78, 
 freezes, Keir. 
 
 Putrid fermentation, i^oarcrqy. 
 
 Vinous fermentation begins, 
 Fourcrou. 
 
 Oil of anise freezes. 
 
 Animal putrefaction, 70 to 
 
 panary fermentation. 
 
 Camphor evaporates, Fourcroy 
 
 Butter melts. 
 
 Summer heat at Edinburgh. 
 
 Vinous fermentation rapid, 
 Fouicroy. Acetous ditto 
 begins. 
 
 Phosphorus bums in oxygen 
 gas. 104, Goellling. 
 
 Summer heat in England. 
 
 Heat of the ocean under the 
 
 The adipocere of muscle melts. 
 
 Acetous fermentation ceases, 
 Foureroy. Phosphorus is 
 ductile. 
 
 Heat of the human body. 
 
 Axunge melts, Nicholson. 
 
 Heat of a swarm of bees. 
 
 Ether boils. 
 
 Phosphoras melts, Pelletier. 
 
 Heat of domestic quadrupeds. 
 
 Resin of bile melts. 
 
 Heat of Birds. 
 
 Feverish heat. 
 
 Hens hatch eggs. 
 
 Myrtle wax melts. Cadet. 
 
 Heat of the air near Senegal. 
 
Tallow melts, Nicholson. 
 
 Ammonia is separated frt 
 
 Ammonia boils, Dalton. 
 Bees-wax melts, Irvine. 
 Camphor sublimes, Ventu 
 Ambergris melts,ZflGra» 
 Bleachedwax melts, iViVAo/n 
 Albumen coagulates. It 
 Blact. 
 
 Sulphur evaporates, Kirvia 
 Alcohol boils, in, Blaci 
 Adipocere of biliary calc 
 melts, Fourcroy. 
 
 Water and volatile oils b( 
 Bismuth 5 parts, tin 3, a 
 lead 2, melt. 
 
 Phosphorus begins to dis 
 Pelletier. 
 
 Muriate of lime boils, Dalt 
 Sulphur melts, Do/te. 21'. 
 
 Fourcroy. 185°, Kirmi, 
 Nitrous acid boils. 
 
 Nitric acid boils. 
 
 Air breathed by the hun 
 species with tolerable ea 
 
 FKil Tramac. ml. 65. 
 
 White oxide of arsenic 
 blimes. Alloy of equal pa 
 of tin and bismuth melts 
 Sulphur burns slowly, : 
 
 camphor melts, Fenturi. 
 Alloys, tin 3 and lead 2, < 
 tin 2 and bismuth 1, me 
 Tin melts, Crichton. MS, 
 
 Tin 1, and lead 4, melt. 
 Bismuth melts, Irvine. 
 Arsenic sublimes. 
 Phosphorus boils, Pelletier 
 
EFFECTS OF HEAT. 
 
 KEAU. 
 
 EAHR. 
 
 CENT. 
 
 WED. 
 
 
 235 
 
 560 
 
 294 
 
 
 Oil of turpentine 
 
 248 
 
 590 
 
 310 
 
 
 Sulphuricacidboilj, 
 Dalton. 546i 
 
 Blach. 5iO,Berg. 
 
 252 
 
 600 
 
 315 
 
 
 Lintseed oil boils. 
 Sulphur sublimes, 
 Davy. ,’>70,Thom. 
 
 258 
 
 612 
 
 325 
 
 
 Lead melts, Crick- 
 ton. 594, Irvine. 
 585, SecunJat. 
 
 540. Newton. 
 
 269 
 
 635 
 
 335 
 
 
 h-irin’fhe dark! 
 
 279 
 
 660 
 
 350 
 
 
 Mercuryboil5,Z)A/- 
 ton.6ii,Secundat. 
 600, Black. 
 
 297 
 
 700 
 
 371 
 
 
 Zinc melts. 
 
 315 
 
 750 
 
 384 
 
 
 Iron bright red ia 
 the dark. 
 
 341 
 
 800 
 
 427 
 
 
 Hydrogen gasbums. 
 1000, Thomson. 
 
 342 
 
 802 
 
 428 
 
 
 Cbarcoalbum,TXom- 
 
 345 
 
 809 
 
 432 
 
 
 Antfmony melts 
 
 380 
 
 884 
 
 475 
 
 
 Iron red in tbe twi- 
 
 448 
 
 1050 
 
 560 
 
 
 I h 
 
 common fire. 
 
 462 
 
 1077 
 
 577 
 
 0 
 
 Red heat in day¬ 
 light. 
 
 564 
 
 1300 
 
 705 
 
 1.7 
 
 Azotic gas burns. 
 
 737 
 
 1807 
 
 986 
 
 6 
 
 Enamel coloursbum. 
 
 -1451 
 
 2897 > 
 
 1814 
 
 14 
 
 Diamondbums. 1, 
 SirG.M’Kenzie. 
 5000, Morveau. 
 
 1678 
 
 3807 
 
 2100 
 
 21 
 
 Brass melts. 
 
 2024 
 
 4587 
 
 2530 
 
 27 
 
 Copper melts. 
 
 2082 
 
 4717 
 
 2602 
 
 28 
 
 Silver melts. 
 
 2130 
 
 4847 
 
 2700 
 
 29 
 
 Settbng heat of 
 plate glass. 
 
 2313 
 
 ■ 5237 
 
 2780 
 
 32 
 
 Gold melts. 
 
 2880 
 
 6507 
 
 3580 
 
 40 
 
 Delft ware fired. 
 
EFFECTS OF HEAT. 
 
 REAU. 
 
 FAHR. 
 
 CENT. 
 
 WED. 
 
 
 37S0 
 
 8480 
 
 4680 
 
 57 
 
 Working heat of 
 plate glass. 
 
 4450 
 
 10177 
 
 5610 
 
 70 
 
 t lint glass iurnace. 
 
 5370 
 
 12257 
 
 6770 
 
 86 
 
 Cream coloured 
 stone ware fired. 
 
 5664 
 
 12777 
 
 7080 
 
 90 
 
 Welding heat ot 
 iron least. 
 
 5800 
 
 13267 
 
 7330 
 
 94 
 
 Worcester china 
 vitrified. 
 
 5953 
 
 13427 
 
 ' 7441 
 
 95 
 
 Welding heat of 
 
 6270 
 
 14337 
 
 ' 7850 
 
 62 
 
 Stone ware fired. 
 
 6520 
 
 14727 
 
 8150 
 
 105 
 
 Chelsea china vitri¬ 
 fied. 
 
 
 15637 
 
 8650 
 
 112 
 
 Derby china. 
 
 7025 
 
 15897 
 
 .8770 
 
 114 
 
 Flint glass furnace 
 greatest heat. 
 
 7100 
 
 16007 
 
 '8880 
 
 121 
 
 123 
 
 Bow china vitrified. 
 Equalpartsof chalk 
 and clay melt. 
 
 7460 
 
 16807 
 
 9320 
 
 124 
 
 Elate glass furnace 
 strongest heat. 
 
 7650 
 
 17327 
 
 9600 
 
 125 
 
 Smith’s forge. 
 
 7975 
 
 ■ 17977 
 
 9850 
 
 130 
 
 Cobalt melts. Cast 
 iron melts. 
 
 8250 
 
 18627 
 
 10320 
 
 135 
 
 Bristol china no 
 vitrification at 
 
 9131 
 
 20577 
 
 11414 
 
 150 
 
 Nickel melts. Hes¬ 
 sian crucible melt¬ 
 ed. 
 
 9325 
 
 21097 
 
 11680 
 
 154 
 
 Soft iron nails melt- 
 
 cibl'e.' ^ 
 
 9602 
 
 21637 
 
 12001 
 
 158 
 
 Iron melts. 
 
 9708 
 
 21877 
 
 12136 
 
 160 
 
 Manganese melts. 
 Air furnace. 
 
 10286 
 
 23177 
 
 12857 
 
 170 
 
 Platinum, tungsten, 
 molybdenum, ur¬ 
 anium, and tita¬ 
 nium, melt. 
 
 11100 
 
 25127 
 
 13900 
 
 185 
 
 Greatest heat ob- 
 
 14331 
 
 32277 
 
 16802 
 
 240 
 
 Extremityof wedge- 
 
30 
 
 EFFECTS OF HEAT. 
 
 N. B, As many of these higher num¬ 
 bers were calculated from Wedgewood’s, 
 by the sliding rule, the two or three first 
 figures only can be depended upon as cor¬ 
 rect. They will be found, however, to be 
 sufficiently accurate for most purposes. 
 
 For more full information respecting 
 various constructions of thermometers and 
 pyrometers, I beg leave to refer to Mr. 
 Mmray’s System of Chemistry, vol. 1st. 
 I shall, however, when I come to speak of 
 Mr. Leslie’s experiments, give an account 
 of his diSerendal thermometer. 
 
EFFECTS OF HEAT. 
 
 31 
 
 SECTION 11. 
 
 28. Expansion of bodies is an im¬ 
 portant effect of heat. ' Solids are least 
 expanded, liquids more, and elastic fluids 
 most of all. The law of expansion of all 
 permanently elastic fluids, has already 
 been noticed (Art. 23.), it remains now to 
 notice liquid and solid bodies. 
 
 29. Every body receiving heat, with a 
 few exceptions, when accurately measured, 
 is found to be enlarged, or expanded. 
 
 30. It may be proper to take notice of 
 some of the exceptions to this law,—that 
 bodies are expanded by heat. The most 
 general exception is, that increase of bulk 
 which takes place in several substances in 
 changing from the fluid to the solid state. 
 This is remarkably the case with water, the 
 expansion of which, in freezing, is capable 
 of overcoming a very great resistance, as 
 was proved by Mr. Boyle, by the Floren- 
 
EFFECTS OF HEAT. 
 
 tine academicians, and, more lately, by 
 Major Williams. In one of bis experi¬ 
 ments, by tbe expansive force of freezing, 
 an iron plug, weighing 2i lbs. was pro¬ 
 jected to a distance of 415 feet, with a 
 velocity of more than 20 feet in a second *. 
 
 Hence the bursting, during frost, of 
 pipes for conveying water, the raising of 
 pavement, the falling of parts of neglected 
 buildings, the splitting of trees, rocks, &c. 
 
 31. But a phenomenon still more sin¬ 
 gular is exhibited by water, it expands not 
 only in the instant in which it passes to 
 the solid state, but before it reaches its 
 freezing point. This singular phenom¬ 
 enon appears first to have been observed 
 by Dr. Crotme, towards the close of the 
 17th century. It was afterwards observed 
 by Mairan; but De Luc seems to have been 
 the first who attempted to investigate it 
 with precision. Dr. Hope has since made 
 experiments, from which he infers, that 
 water obtains its maximum density at 40°, 
 
 ctions of Royal Societ; 
 
 ‘ Edinburgh, vol. 2. p. 28. 
 
EFFECTS OF HEAT. 
 
 that is, 8° warmer than at the freezing 
 point, or 32°. Mr. Dalton has also inves¬ 
 tigated this subject, and from his experi¬ 
 ments infers, “ that the greatest density of 
 water^ is at or near the 36° of the old scale, 
 and 37° or 38° of the new scale; and fur¬ 
 ther, that the expansion of thin glass is 
 nearly the same as that of iron, whilst that 
 of stone ware is f, and brown earthen 
 ware i- of the same 
 
 32. Permit me to direct the reader’s 
 attention to this very remarkable fact, that 
 all bodies are condensed by cold without 
 limitation, water only excepted, which we 
 have just seen is, at its greatest density, at 
 36° of Fahrenheit’s scale. This exception 
 to one of those general laws of nature, is a 
 striking proof of contrivance in the arrange¬ 
 ment of the universe. Were it otherwise, 
 all the fresh water within the polar circles 
 must inevitably have been frozen to a very 
 great depth in one winter, and a great 
 portion of what is now the most temper- 
 
 • Dalton’s Chemical Philosophy, p. S4. 
 
34 
 
 EFFECTS OF HEAT. 
 
 ate part of the globe, rendered a dreary- 
 waste. 
 
 To understand this, let us see what 
 takes place in the freezing of a fresh water 
 lake. When the cold air comes in contact 
 with the particles at the surface, they are 
 cooled, and becoming heavier descend 
 until they are cooled down to the point 
 of greatest density. Were this 32“ then 
 the whole water would continue this in¬ 
 ternal motion until it arrived at the freez¬ 
 ing point, and being all equally cold, 
 would become all at once solid ice. 
 
 But the water is heaviest at 36°, of 
 course whenever it is all cooled down to 
 that point, the internal motion ceases, and 
 the surface becomes gradually colder un¬ 
 til it arrive at the freezing point, when a 
 thin body of ice forms a covering to the 
 water, and particularly -when snow' is 
 added, serves to protect it from the influ¬ 
 ence of the colder atmosphere. 
 
 For a fuller account of this instance of 
 
KFFECTS OF HEAT. 
 
 35 
 
 the beautiful economy of nature *, as also 
 what relates to the influence of salt water 
 on the temperature of the globe, I may 
 refer the reader to Count Rumford’s 
 seventh Essay. 
 
 33. According to Smeaton, “ glass ex¬ 
 pands in length for 180° of temperature, 
 consequently it expands ^ in bulk. But 
 water expands tt-t or rather more than 
 eighteen and one-half times as much 
 
 34. A knowledge of the comparative 
 expansions of solids, is of much import¬ 
 ance in the arts, and more particularly 
 in the construction of time-pieces, which 
 are much afiected by the expansion of 
 metals. This has led to a number of 
 experiments on the subject; those of Mr. 
 Ellicotj; appear to have been the first 
 which were made with any degree of ac¬ 
 curacy. He was followed in the same 
 inquiry by Smeaton ||, Roy and Trough- 
 ton and also by M. Berthoud§. 
 
36 
 
 EFFECTS OF HEAT. 
 
 Although we perceive something like a 
 relation subsisting between the expansion 
 and fusibility of solids, those which are 
 most fusible, as antimony, tin, lead, &c. 
 expanding most, yet it must be confessed, 
 that we know but very litde with regard 
 to the connection which subsists between 
 the expansibility and other physical pro¬ 
 perties of solids. 
 
 No general law has hitherto been dis¬ 
 covered, respecting the ratio of expansion 
 
 of solid bodies; but for all practical pur¬ 
 poses, we may adopt the notion of the 
 equable expansion of solids. Glass, how¬ 
 ever, is an exception, for it has been foimd 
 to expand in a ratio which increases -with 
 the temperature. 
 
 For measuring the longitudinal expan¬ 
 sion of solids, various instniments, or py¬ 
 rometers, have been invented, accounts of 
 which may be found in most books, on 
 natural philosophy. “ The longitudinal 
 expansion being found, that of the bulk 
 may be derived from it, and will be three 
 
EFFECTS OF HEAT. 
 
 37 
 
 times as much. Thus, if a bar of 1000 
 expand to 1001 by a certain temperature, 
 then a 1000 cubic inches of the same, will 
 become 1003 by the same temperature 
 
EFFECTS OF HEAT. 
 
 35. TABLE of EXPANSIONS, for 180* of 
 
 Fahrenheit *. 
 
 Solids, 
 
 Earthen ware. 
 
 
 in Bulk. 
 
 Wedgewood says, 
 that earthen ware 
 made porous by 
 charcoal,expanded 
 only one-third as 
 much as when 
 solid. 
 
 Brown earthen ware. 
 
 .000416 
 
 .0012 
 
 Dalton. 
 
 Stone ware. 
 
 Wood. 
 
 ,000208 
 
 .0012 
 
 Do. 
 
 Much less than glass. 
 Rittenhouse, 
 
 Glass rods and tubes. 
 
 .000208 
 
 .0025 
 
 Dalton. 
 
 -bulbs thin. 
 
 .001234 
 
 .0037 
 
 Do. 
 
 
 0007761S 
 
 .002330 
 
 Roy.—Phil. Trans. 
 1785. Hehadbe- 
 
 tube expand four 
 
 
 50083333 
 
 .002502 
 
 Smeaton, Philosoph. 
 Transac. 1754. 
 
 Glass rod. 
 
 Deal. 
 
 00080787 
 
 .002426 
 
 Roy, the same glass 
 as the tube. 
 
 Roy, 1777, as glass. 
 
 
 .000856 
 
 .002570 
 
 Borda. 
 
 Platina and glass. 
 
 .0011 
 
 .0033 
 
 Berthoud. 
 
 Repilusof antimony. 
 
 .001083 
 
 .003253 
 
 Smeaton. 
 
 Cast-iron prism. 
 
 .0011094 
 
 .003332 
 
 Roy. 
 
 Cast-iron. 
 
 .0011111 
 
 .003337 
 
 Lavoisier. 
 
 Steel rod. 
 
 .0011447 
 
 .003438 
 
 Roy. 
 
 Blistered Steel. 
 
 .001125 
 
 .001150 
 
 .003379 
 
 .003454 
 
 Phil. Trans. 1795, 
 428. 
 
 Smeaton. 
 
 Steel. 
 
 .00115741 
 
 .003476 
 
 Lavoisier. 
 
 Hard Steel. 
 
 .001225 
 
 .003679 
 
 Smeaton. 
 
 Annealed Steel. 
 
 .00122 
 
 .00367 
 
 Musschenbroek. 
 
 Tempered Steel. 
 
 .00137 1 
 
 .00111 
 
 Musschenbroeh. 
 
 • See Dalton’s Chem. Phil. p. 44. and Young’s Nat. PhiL vol. 2. 
 p. 390—391. 
 
EFFECTS OF HEAT. 
 
 Solids. 
 
 in Length 
 
 in Bulk. 
 
 
 Iron. 
 
 .001156 
 
 .003472 
 
 Borda. 
 
 
 .001258 
 
 .003779 
 
 Smeaton. 
 
 Annealed Iron. 
 
 .00133 
 
 .00400 
 
 Musschenbroek. 
 
 Hammered Iron. 
 
 .00139 
 
 .00417 
 
 Musschenbroek. 
 
 Bismuth. 
 
 .001392 
 
 .004180 
 
 Smeaton. 
 
 Annealed gold. 
 
 .00146 
 
 .00438 
 
 Musschenbroek. 
 
 Gold. 
 
 ■0015 
 
 .0045 
 
 Ellicot, by compari- 
 
 Gold wire. 
 
 .00167 
 
 .00502 
 
 Musschenbroek. 
 
 Copper hammered. 
 
 .001700 
 
 .005109 
 
 Smeaton. 
 
 Copper. 
 
 .00191 
 
 .00573 
 
 Musschenbroek. 
 
 Brass. 
 
 .001783 
 
 .005359 
 
 Borda. 
 
 from Hamburgh. 
 
 .0018554 
 
 .005576 
 
 Roy. 
 
 
 
 
 Cast Brass. 
 
 .001875 
 
 .005635 
 
 Smeaton. 
 
 English plate brass 
 
 .0018928 
 
 .005689 
 
 Roy. 
 
 English plate brass 
 
 .0018949 
 
 .005695 
 
 Roy. 
 
 trough. 
 
 
 
 
 .001933 
 
 .005811 
 
 Smeaton. 
 
 Brass. 
 
 .00216 
 
 .00648 
 
 Musschenbroek. 
 
 Copper 8 tin 1. 
 
 .001817 
 
 .005461 
 
 
 Silver. 
 
 .00189 
 
 .005681 
 
 Herbert. 
 
 — 
 
 .0021 
 
 .0063 
 
 Ellicott, by com- 
 
 — 
 
 .00212 
 
 .00636 
 
 Musschenbroek. 
 
 Brass 16 tin 1. 
 
 .001908 
 
 .005736 
 
 Smeaton. 
 
 Speculum metal. 
 
 .001933 
 
 .005811 
 
 Smeaton. 
 
 Spelter solder brass 
 
 .002058 
 
 .006187 
 
 Smeaton. 
 
 2 zinc 1. 
 
 
 
 
 Fine pewter. 
 
 
 .006866 
 
 Smeaton. 
 
 Grain tin. 
 
 .002483 
 
 .007469 
 
 Smeaton! 
 
 Tin, 
 
 .00284 
 
 .00852 
 
 Musschenbroek. 
 
 Soft solder, lead 2 
 
 .002508 
 
 .007545 
 
 Smeaton. 
 
 Zinc 8 tin 1 a little 
 
 .002692 
 
 .008095 
 
 Smeaton. 
 
 hammered. 
 
 
 
 Lead. 
 
 .002867 
 
 .008625 
 
 Smeaton. 
 
 Zinc. 
 
 .00344 
 
 .01032 
 
 Musschenbroek. 
 
 .002942 
 
 .008850 
 
 Smeaton. 
 
 Zinc hammered out 
 
 .003011 
 
 .009061 
 
 Smeaton. 
 
 half aninchperfoot. 
 
 
 
40 
 
 EFFECTS OF HEAT. 
 
 Liquids. 
 
 ExpanaoD in Bulks. 
 
 Merciuy, - -- - 
 
 Water,. 
 
 Water saturated with salt, . . . . 
 
 Sulphuric acid, 
 
 Muriatic acid, .. 
 
 Oil of turpentine, ....... 
 
 Ether, .......... 
 
 Fixed Oils,. 
 
 Alcohol, .. 
 
 Nutric acid, ... 
 
 0700 = -,% 
 
 0110 = ^ 
 0110 = 1 
 
EFFECTS OF HEAT. 
 
 41 
 
 SECTION III, 
 
 On the Spec^ic Heat of Bodies. 
 
 S6. It was already observed, (Art. 3.) 
 that different bodies at the same tempera¬ 
 ture, and showing the same degree on the 
 thermometer, really contain different 
 quantities of heat. 
 
 This divetsity of the quantity of heat 
 contained in different bodies, is called 
 specific heat; and, accordingly, tables of the 
 specific heat of bodies, showing their com¬ 
 parative attractions for heat, have been 
 formed in a similar manner with tables of 
 specific gravity, which show the compara¬ 
 tive weights of bodies of equal bulks. 
 
 Sometimes the specific heat of bodies is 
 deduced from equal 'weights^ and some¬ 
 times from equal bulks, but it seems to be 
 most correct to deduce them from equal 
 hulks 
 
 * See Dalton’s Chemical Philosophy, p. 2. 
 
 F 
 
42 
 
 i-FFECTS OF HEAT= 
 
 Not being susceptible of measurement 
 by the thermometer, different modes have 
 been contrived for estimating it. 
 
 Lavoisier and Laplace used an ingenious 
 contrivance called a calomiter, for investi¬ 
 gating the specific heat of bodies. It was. 
 calculated to show the quantity of ice, 
 which any body heated to a given tem¬ 
 perature could meltj but, however ingen¬ 
 ious in its construction, this instrument 
 has not been found in practice to be 
 sufficiently accurate. 
 
 Meyer attempted to find the specific 
 heats of dried woods, by observing the 
 times which equal volumes were in cool¬ 
 ing. These times, he considered as pro¬ 
 portionate to the capacities, or specific 
 heats hulk for hulk, and when the times 
 were divided by the specific gravities, the 
 quotients represented the capacities of 
 equal weights. This method was applied 
 by Mr. Leslie to liquids, and has been 
 approved of, and follovfed by Mr. Dalton. 
 
EFFECTS OF HEAT. 
 
 43 
 
 37. The important fact of the absorption 
 of heat, during the conversion of ice into 
 water, appears to have been first observed, 
 separately and unknown to each other, by 
 De Luc, Black, and Wilkie, about the year 
 1755. On this experiment. Dr. Black 
 principally founded his doctrine of latent 
 heat. Dr. Irvine and Dr. Crawford, ex¬ 
 plained the circumstances somewhat dif¬ 
 ferently, by the theory of a change of 
 
 capacity for heat. Dr. Black’s theory led 
 to very vague, indistinct, and inaccurate 
 notions on the subject; nor was the word 
 capacity well chosen. The term specific heat, 
 is that which is more approved by later 
 writers, particularly Dalton and Leslie 
 
 38. By the method already mentioned, 
 (Art. 38.) making proper allowance for 
 the containing glass vessels, Mr, Dalton 
 made his experiments on the specific heats 
 of various bodies, the results of which 
 will be found in the following Table. It 
 will be sufficient to illucidate the use of 
 
 • See Dalton’s Chem. Phil—Leslie’s Inquir)', p. 529, also Mr. Til- 
 loch’s paper, Phil. Mag. 1808, p. 70. 
 
44 EFFECTS OF HEAT. 
 
 the table, to give water and mercury as 
 examples. 
 
 “ If the whole quantity of heat in a 
 measure of water of a certain tempera¬ 
 ture be denoted by 1, that in the same 
 measure of mercury will be denoted by .5 
 nearly; hence the specific heats of water, 
 and mercury, of equal bulks, may be sig¬ 
 nified by 1 and .5 respectively. 
 
 “ If the specific heats, be taken from 
 equal •weights of the two liquids; then they 
 will be denoted by 1 and .04 nearly, because 
 we have to divide .5 by 13.6, the specific 
 gravity of mercury 
 
 Mr. Dalton has discovered that water 
 increases in its capacity for heat with 
 the increase of temperamre, and infers, 
 that as much heat is necessary to raise 
 water 5° in the lower part of Fahrenheit’s 
 scale, as is required to raise it 7° in the 
 higher, and 6° in the middle. 
 
 • Dalton, p. 47. 
 
EFFECTS OF HEAT. 
 
 45 
 
 39. TABLE of Specific Heats. 
 
 Hydrogen ... - 
 
 Oxygen. 
 
 Common air - -- -- -- - 
 
 Carbonic acid - -- -- -- - 
 
 Azotic . 
 
 Aqueous vapour ....... 
 
 LIQUIDS. 
 
 Arterial blood - -. 
 
 Milk (1.026). 
 
 Carbonat. of ammonia (1.033) - - 
 
 Carbonat. of pot-ash (1.30) - - - 
 
 Solut. of ammonia (.948) - - - 
 
 Common vinegar (1.02) - - - - 
 
 Venous blood ........ 
 
 Solut. of common salt (1.197) 
 
 Solut. of sugar (1.17) - . . - 
 
 Nitric acid (1.20). 
 
 Nitric acid (].30). 
 
 Nitric acid (1.36) ------ 
 
 Nitrateof lime (1.40). 
 
 Sulphuric acid and water, equal bulks 
 
 Muriatic acid (1.153). 
 
 Acetic acid (1.056). 
 
 Sulphuric acid (1.844). 
 
 Alcohol (.85). 
 
 Ditto (.817) -------- 
 
 Sulphuric ether (.76). 
 
 Spermaceti oil (.87). 
 
 Mercury.. 
 
 121.40* I 
 4.75* 
 1.79* 
 1.05*1 
 .79* 
 1.55* 
 
46 
 
 EFFECTS OF HEAT. 
 
 Dried woods, and other vegetable substances 
 from A3 to - -- -- -- -- 
 Quicklime - 
 
 Pit-coal (1.27). 
 
 Charcoal .. 
 
 Chalk. 
 
 Hydrat. lime. 
 
 Flint glass (2.87) - - -. 
 
 Munate of soda ......... 
 
 Sulphur - 
 
 Gold.. 
 
 Bismuth - . 
 
 Oxides of the metals surpass the metals 
 themselves, according to Crawford, 
 
EFFECTS OF HEAT. 
 
 47 
 
 Eemarlcs on the Table. 
 
 “ The articles marked * are from 
 Crawford. Notwithstanding the ingen¬ 
 uity and address displayed in his experi¬ 
 ments on the capacities of the elastic 
 fluids, there is reason to believe his results 
 are not very near approximations to the 
 truth; we can never expect accuracy when 
 it depends upon the observation of 1 or 2 
 tenths of a degree of temperature after a 
 tedious and complicated process. Great 
 merit is undoubtedly due to him for the 
 attempt.—The difference between arterial 
 and venous blood, on which he has 
 founded the beautiful system of animal 
 heat, is remarkable, and deserves further 
 inquiry f.” For some account of Dr. Craw¬ 
 ford’s theory here alluded to, see Thomson’s 
 Chemistry, vol. iv. p. 72,—also, Adam’s 
 Lect. on Nat. Phil. vol. i. p, 396. But 
 those who wish fuller information, I would 
 refer to Dr. Crawford’s valuable “ Ex¬ 
 periments and observations on Animal 
 Heat.” 
 
EFFECTS OF HEAT. 
 
 40. “ Water appears to possess the 
 greatest capacity for heat of any pure 
 liquid yet known, whether it be compared 
 with equal bulks or weights; indeed it 
 may be doubted, whether any solid or 
 liquid whatever contains more heat than 
 an equal bulk of water of the same tem¬ 
 perature. The great capacity of water, 
 arises from the strong affinity which 
 both its elements, hydrogen, and oxigen, 
 have for heat. Hence it is that solutions 
 of salts in water, contain generally less 
 heat in a given volume than pure water: 
 for salts increase the volume of water as 
 well as the density, and having mostly a 
 small capacity for heat, they enlarge the 
 volume of the^water more than pi'oportional 
 to the heat they contribute 
 
 41. It is of importance to obtain the 
 exact specific heat of the elastic fluids, 
 because it has an intimate connection 
 with the phenomena of combustion, and 
 of heat in general. Of these, Mr. Dalton 
 has given a theory, upon the principles of 
 
EFFECTS OF HEAT. 49 
 
 which, he has calculated the following 
 table, respecting which he, says, 
 
 “ We shall have the specific heats, of the 
 several elastic fluids, as in the following 
 table. In order to compare them with 
 that of water, we shall further assume the 
 the specific heat of water, to that of steam, 
 as 6 to 7, or as 1 to 1.166.” 
 
 42. “ TABLE of the Specific Heats of Elastic 
 Fluids. 
 
 Hydrogen - - . 9.382 
 Azote .... 1.866 
 
 Oxygen - - - 1.333 
 
 Atmos, air - - - 1.7S9 
 Nitrous gas - - . .777 
 Nitrous oxide . . .549 
 Carbonic acid . - .491 
 Ammon, gas - - l.SSS 
 Carb. hydrogen - - 1333 
 
 Olefiant gas - . 1. 555 
 Nitric acid . . - .491 
 Carbonic oxide - - .777 
 SiJph. hydrogen - .583 
 Muriatic acid - . . .424 
 Aqueous vapour . 1.166 
 Ether, vapour . . .848 
 Alcohol, vapour . - .586 
 Water - - - . I.OOO 
 
 “ Let US now see how far these results 
 will accord with experience. It is remark¬ 
 able, that the heat of common air comes 
 out nearly the same as Crawford found it 
 by experiment; also hydrogen excells all 
 the rest, as he determined, but oxygen is 
 much lower, and azote higher. The 
 G 
 
so EFFECTS OF HEAT. 
 
 principles of Crawford’s doctrine of animal 
 heat, and combustion, however are not at 
 all affected with the change *, 
 
 43. The phenomenon of animal heat 
 has from the earliest ages been the subject 
 of philosphical discussion, but its cause 
 seems not yet ascertained. Of this, there 
 are various degrees, some animals preserv¬ 
 ing a heat of 100° or more in all tempera¬ 
 tures of the atmosphere; others, particularly 
 the more imperfect, keep only a few degrees 
 warmer than the medium, with which they 
 are surrounded. That of the human body 
 is from 96° to 98°, and it is tniely wonder¬ 
 ful that it should remain nearly the same 
 in all climates. Men have lived in cold 
 greater than that at which mercury freezes, 
 (which is at 39° below zero,) and in an at¬ 
 mosphere above the heat of boiling water. 
 Mr. M‘Nab observed cold at Hudson’s Bay 
 50° below zero. While the human species 
 have, vyith impunity, breathed air 264* j-, 
 none of the inferior animals, seem capable 
 
 * Dalton, pge 7S, 74. 
 
 t See Phil. Tran. Vol €S. 
 
EFFECTS OF HEAT. 
 
 51 
 
 of sustaining this change of temperature, 
 while to man has been giten this wonder¬ 
 ful power of enduring all the variety of 
 climates, which his necessities, or desire 
 of knowledge, could lead him to visit, 
 (Art. 27,) 
 
 I hope the following quotations, relative 
 to the power of animals to sustain heat, 
 will be acceptable to the reader. 
 
 “ Air has often been breathed by the 
 human species, with impunity, at 264°. 
 Tillet mentions its having been respired at 
 300; and Morantin, one instance, at 325°, 
 and that for the space of five minutes.' 
 Sonnerat found fishes, existing in a hot 
 spring at the Manillas at 158° *: and M. 
 Humboldt and M. Bonpland, in travelling 
 through the province of Quito, in South 
 America, perceived other fishes thrown up 
 alive, and apparently in health, from the 
 bottom of a vulcano, in the course of its 
 explosions along with water, and heated 
 
 • He graduates by Reaumur’s thermometer, and calculates the heat 
 upon this at 69°. 
 
EFFECTS OF HEAT. 
 
 vapour that raised the thermometer to 210°, 
 being only two degrees short of the boiling 
 point 
 
 “ There are indeed ntimerous facts, all 
 of which tend to confirm the statement of 
 these inti-epid travellers. Dogs have exist¬ 
 ed without apparent inconvenience, in a 
 temperature of 236°, measured by Fah¬ 
 renheit’s thermometer; a heat exceeding 
 that of boiling water, by 24°. A species of 
 toenia has been fotmd alive in a boiled carp; 
 the oven-girls in some part of Germany, 
 have sustained a heat of 257° for a quarter 
 of an horn; one girl supported it ten 
 minutes, when augmented to 288° without 
 inconvenience, and another, breathed in 
 air, heated to 325° for five minutes f; the 
 incombustible man, described by Dr. Sem- 
 entini, of Naples, would receive boiling oil 
 into his mouth, and bathe his fingers in 
 fused lead without injury f; and, to come 
 nearer home. Sir Joseph Banks, bore a 
 
 • Acniversary oration delivered, March 8,1808, before the Medical 
 Society of London, by John Mason Good, F, R. S. 
 
 + Hist. Acad. Scienc. 1764. | Phil. Mag. vol. xixii. 
 
EFFECTS-OF HEAT. 53' 
 
 heated room, at 211°, while Sir Charles 
 Blagden, has himself given an account^ 
 of his sustaining the heat of 260° in the 
 surrounding facticious atmosphere f.” 
 
 44. Bodies by changing their state, also 
 change their specific heat. By a change of 
 state in bodies, is meant their successive 
 passage from solidity to liquidity, and 
 from this to elastic fluidity, and contrari¬ 
 wise. Thus water may be in the state of 
 ice, of liquid, and of vapour, or steam. 
 
 A solid body, as ice, on becoming liquid, 
 acqioires a great specific heat, even though 
 its bulk be diminished; and a liquid, as 
 water, acquires a greater specific heat, on 
 being converted into an elastic fluid. 
 
 It was already mentioned, (Art. 39.) that 
 the absorption of heat, during the conver¬ 
 sion of ice into water, was observed by 
 philosophers, about the year 1755; and Dr. 
 Crawford has shown, that by the laws of 
 
 • Phil. Trans, vols. kv. and kviii. f Eclectic Rev. March, 1809. 
 
54 
 
 EFFECTS OF HEAT. 
 
 absorption and extrication of beat, resulting 
 from the change of capacity, -which takes 
 place in the solid and fluid states of water. 
 Divine Providence, has wisely guarded 
 against various sudden -ricissitudes of heat 
 and cold upon the surface of the earth. 
 A vast quantity of heat is extricated in 
 freezing of large masses, which renders the 
 process very slow, while the great absorp¬ 
 tion of heat from the atmosphere, in 
 thawing, occupies much time, and prevents 
 that terrible devastation, which otherwise 
 would take place from torrents produced 
 by the sudden dissolution of ice and 
 snow. 
 
 45. During the conversion of water into 
 steam, a great quantity of heat is absorbed; 
 in consequence of which, when steam is 
 again converted into water, much heat is 
 extricated. 
 
 Hence the water which results from 
 condensation, forms an accurate compara¬ 
 tive measure of the heat extricated from 
 steam of the same density, and, for this 
 
EFFECTS OF HEAT. 
 
 55 
 
 purpose, it was applied in experiments 
 made by Mr. Houldswortb*, in comparing 
 the effects of steam-tubes of tin-plate with 
 those of cast-iron. , The subject of steam 
 will be farther considered, after treating 
 of Ebullition. 
 
 •See Part II. 
 
56 
 
 EFFECTS OF HEAT. 
 
 SECTION IV. 
 
 Of Cambustim. 
 
 46. Modem chemists consider the 
 sources of heat, which are under the 
 control of art to be the following:— 
 Solar rays, electricity and galvanism, 
 condensation, mechanical action between 
 solids, including friction and percussion, 
 and chemical action, to which head com¬ 
 bustion belongs *. 
 
 Otir concern at present is with com- 
 bustionj but before proceeding to that 
 sttbject, I shall very shortly notice some 
 of the other sources of heat. 
 
 4*7. It has been long known, that col¬ 
 oured bodies when exposed to the light of 
 the Sun, have their temperature raised in 
 proportion to the darkness of their colour. 
 —^The simple experiment of touching a 
 white and a black stone exposed to tie 
 
EFFECTS OF HEAT. 
 
 57 
 
 rays of the sun, would be sufficient to 
 give any one an idea of this truth. To 
 ascertain this point, experiments were made 
 , by Dr. Hooke, by Dr. Franklin, and since, 
 with more precision, by Mr, Davy *. 
 
 48. The temperature produced by the 
 direct action of the rays of the sun, seldom 
 exceeds 120°, but when they are concen¬ 
 trated, they are capable of producing a 
 temperature as great at least, as the most 
 intense and violent fires f. 
 
 49. Condensation of volume, it is 
 well known, produces heat, This fact was 
 long ago observed in condensing air in the 
 air-gun. A curious application of this 
 principle was, a few years ago, invented 
 
 in France, and is now coming into use in 
 this country. I allude to an instrument 
 for kindling fungus, used instead of the 
 tinder-box. It is simply a condenser, 
 which, by compressing the air into a very 
 small space, by a single stroke of the piston, 
 sets fire to the fungus. 
 
 * Thomson’s Chemistry, vol. i. page 419. f Ibid, page 41C. 
 
58 
 
 EFFECTS OF HEAT. 
 
 Mr. Dalton accounts for the decrease 
 of temperature of the atmosphere as we 
 ascend, by supposing that the ' natural 
 equilibrium of heat is an equality in quantity 
 rather than temperature. Air increases in 
 its capacit}' for heat by rarefaction. The 
 temperature must, therefore, be regulated 
 by the density of each atom of air, in the 
 same perpendicular column, being pos¬ 
 sessed of the same quantity of heat. Now, 
 it is well known, that the density of the 
 air becomes less as we ascend, and, of 
 course, the heat also decreases *. 
 
 50. Mr. Dalton is likewise of opinion, 
 that the heat produced by friction and 
 PERCUSSION, of solid bodies, ■ results, in 
 both cases, from the same cause, viz. con¬ 
 densation of volume, in the same manner 
 as the condensation of air and other bodies 
 produces heat f. (See Art. 49.) 
 
 51. It was the opinion of Crawford, 
 Lavoisier, and many other modern chemists, 
 
 • Dalton’s Chem. PhiL p. 123. f Dalton’s Chemistry, p.I23—133. 
 
EFFECTS OF HEAT. 
 
 59 
 
 that oxygenous gas was the sole or prin¬ 
 cipal source of the light and heat produced 
 by combustion. But Mr. Dalton has 
 proved, that although this may be nearly 
 the case with regard to charcdal and pit- 
 coal, that it is not true with regard to 
 other combustible bodies. He concludes, 
 
 “ that the heat, and probably the light 
 also, evolved by combustion, must be con¬ 
 ceived to be derived both from the oxygen 
 and the combustible body, and that each 
 contributes, for ought we know to the 
 contrary, in proportion to its specific heat 
 
 before the combustion,” * (Art. 43.) 
 
 Fml. 
 
 52. Dr. Black considers the fuels com¬ 
 monly used, under five divisions:—“ The 
 first may comprehend the fluid inflam- 
 ables; to the second we may refer peat or 
 turf; to the third, charcoal of wood; to 
 the fourth, pit-coal charred; and to the 
 fifth, wood or pit-coal in a crude state, and 
 capable of yielding a copious and bright 
 flame.— 
 
 • Dalton’s Chem. Phil. p. 81—82. 
 
60 
 
 EFFECTS OF HEAT. 
 
 53. “ 1j/, The fluid inflamables are con¬ 
 sidered as distinct from the solid, on this 
 account, that they are capable of burning 
 upon a wick, and become in this way the 
 most manageable sources of heat; though, 
 on account of their price, they are never 
 employed^ for producing it in great quan¬ 
 tity, and are only used when a gentle 
 degree, or a small quantity of heat is suf¬ 
 ficient. The species which belong to this 
 class, are spirit of wine and different oils.” 
 
 54. “ The second kind of fuel men¬ 
 tioned, peat, is so spongy, that compared 
 with the more solid fuels, it is unfit to be 
 employed for producing very strong heats. 
 —^It is too bjilky for this.—^We caimot put 
 into a furnace, at a time, a quantity that 
 corresponds with the quick consumption 
 that must necessarily go on when the heat 
 is violent. There is no doubt a great dif¬ 
 ference in this respect, among difierent 
 kinds of this fuel; but this is the general 
 character of it. HowCver, when we desire 
 to produce and keep up, by means of 
 cheap fuel, an extremely mild gentle heat, 
 
EFFECTS OF HEAT. 
 
 61 
 
 we can hardly use any thing better than 
 peat. But it is best to have it previously 
 charred, that is, scorched, or burned to 
 black coal. The advantages gained by 
 charring it, will be presently explained. 
 When prepared for use in that manner, it 
 is capable of being made to burn more 
 slowly and gently, or will bear, without 
 being extinguished altogether, a greater 
 
 diminution of the quantity of air with 
 
 which it is supplied, than any other of the 
 solid fuels. Dr. Boerhaave found it ex¬ 
 tremely convenient and manageable in his 
 Furnus Studiosorum. 
 
 55. “ The next fuel in order, is the 
 charcoal of wood. This is the chief fuel 
 used by the chemists abroad, and has 
 many good properties. It kindles quickly, 
 emits few watery or other vapours while 
 burning, and when consumed, leaves few 
 ashes, and those very .light. They are, 
 therefore, easily blown away, so that the 
 fire continues open, or pervious to the 
 current of air which must pass through 
 it to keep it burning. This sort of fuel 
 
EFFECTS OF HEAT. 
 
 too, is capable of producing as intense a 
 heat as can be obtained by any; but in 
 those violent heats it is quickly consumed, 
 and needs to be frequently supplied. 
 
 55. “ Fossil coals charred^ called cinders 
 or coaks, have, in many respects, the same 
 properties as charcoal of wood; as kin¬ 
 dling more readily in furnaces, than when 
 they are not charred, and not emitting 
 watery or other gross smoke while they 
 bum. This sort of charcoal is even greatly 
 superior to the other in some properties. 
 It is a much stronger fuel, or contains the 
 inflamable matter in greater quantity, or 
 in a more condensed state. It is, tlierefore, 
 consumed much more slowly on all occa¬ 
 sions, and particularly when employed for 
 producing intense melting heats. The 
 only inconveniences that attend it are, that 
 when it consumes, it leaves much more 
 ashes than the other*, and these much 
 
 * X do not know that this is the case with the finest pit-coal. 1 
 have seen some of the finest Newcastle coals which did not leave one 
 fiftieth part of their weight of ashes, and e%'en these did not seem 
 entirely consumed. 
 
EFFECTS OF HEAT, 
 
 63 
 
 heavier too, which are, therefore, liable to 
 collect in such quantity, as to obstruct the 
 free passage of air through the fire; and 
 farther, that when the heat is very intense, 
 these ashes are disposed to melt or vitrify 
 into a tenacious drossy substance, whicK 
 clogs the grate, the sides of the furnace, 
 and the vessels. This last inconvenience 
 is only troublesome, however, when the 
 heat required is very intense. In ordinary 
 heats the ashes do not melt, and though 
 they are more copious and heavy than 
 those of . charcoal of wood, they seldom 
 choke up the fire considerably, unless the 
 bars of the grate be too close together. 
 
 “ This fuel, therefore, is preferable in 
 most cases, to the charcoal of wood, on 
 account of its burning much longer, or 
 giving much more heat before it is con¬ 
 sumed, T/ie heat produced by equal quan¬ 
 tities, by weight of pit-coal, wood^charcoal, 
 and wood itself, are nearly in the proportion 
 of 5, 4, and 3. The reason why both these 
 kinds of charcoal are preferred, on most 
 occasions, in experimental chemistry, to 
 
EFFECTS OF HEAT. 
 
 6i 
 
 the crude wood and fossil-coal, from which 
 they are produced, is, that the crude fuels 
 are deprived, by charring, of a consider¬ 
 able quantity of water, and some other 
 volatile principles, which are evaporated 
 during the process of charring, in the 
 form of sooty smoke or flame. These 
 volatile parts, while they remain in the 
 fuel, make it imfit^(or less fit) for. many 
 purposes in chemistry. For, besides ob¬ 
 structing the vents with sooty matter, 
 they require much heat to evaporate them, 
 and, therefore, the heat of the furnace in 
 which they are burned is much dimin¬ 
 ished, and wasted by every addition of 
 fresh fuel, until the fresh fuel is com¬ 
 pletely inflarned, and restores the heat to 
 its former strength. But these great and 
 sudden variations of the heat of a furnace, 
 are quite inconvenient in most chemical 
 processes. In the greater number of chem¬ 
 ical operations, therefore, it is much more 
 convenient to use charred fuel, than the 
 same fuel in its natural state. 
 
EFFECTS OF HEAT, 
 
 65 
 
 57. “ The last kind of fuel is ’wood, or 
 fossil coal in their crude state, which it is 
 proper to distinguish from the charcoals 
 of the same substances. The diflPerence 
 consists in their giving a copious and 
 bright flame, when plenty of air is admit¬ 
 ted to them, in consequence of which they 
 must be considered as fuels, very different 
 from charcoal, and adapted to different 
 purposes. 
 
 “ I had occasion formerly to remark, 
 when treating of inflamation, that flame is 
 produced from those substances only, 
 which are either totally volatile when heat 
 is applied to them, or which contain a 
 quantity of combustible matter that is 
 volatile, or easily convertible into vapour 
 by heat; and that flame is nothing else 
 but this vapour set on fire, or which 
 becomes inflamed as fast as it arises from 
 the body which affords it. 
 
 “ Of this nature, therefore, is the flame 
 of wood and fossil coal, when they are 
 burned in their crude state. These fuels 
 I 
 
EFFECTS OF HEAT. 
 
 contain a quantity of inflamable matter, 
 that is volatile, and which, when a 
 moderate and stifled heat is applied to 
 them, evaporates in the form of oily and 
 sooty vapours and smoke, and diminishes 
 the heat instead of increasing it. But if 
 they are exposed to a stronger heat, and 
 air is freely admitted, the sooty vapours 
 are suddenly set on fire, or become flame, 
 and continue afterwards to burn as fast as 
 tliey arise from the wood or coal, in con¬ 
 sequence of vrhich they produce a great 
 
 “ These flaming fuels, however, have 
 their particular uses, for which the others 
 are far less proper; for it is a fact, that 
 flame, when produced in great quantity, 
 and made to burn violently, by mixing it 
 with a proper quantity of fresh air, by 
 driving it on the subject, and throwing it 
 into whirls and eddies, which mix the air 
 with every part of the hot vapour, gives a 
 most intense heat. This proceeds from 
 the vaporous nature of flame, and the 
 perfect miscibility of it with the air. As 
 
EFFECTS OF HEAT. 
 
 67 
 
 the immediate contact and action of air is 
 necessary to the burning of every com¬ 
 bustible body, so the air, when properly 
 applied, acts with far greater advantage on 
 flame, than on the solid and fixed inflam- 
 able bodies, for when air is applied to 
 these last, it can only act on their surface 
 or the particles of them that are outermost; 
 whereas flame being a vapour or elastic 
 fluid, the air by proper contrivances can 
 be intimately mixed with it, and made to 
 act on every part of it, external and inter¬ 
 nal at the same time.—The great power 
 of flame, which is the consequence of this, 
 does not appear when we try small quan¬ 
 tities of it, and allow it to burn quietly, 
 because the air is not intimately mixed 
 with it, but acts only on the outside, and 
 the quantity of burning matter in the 
 surface of a small flame, is too small to 
 produce much effect. But when flame 
 is produced in large quantity, and is pro¬ 
 perly mixed and agitated with air, its 
 power to heat bodies is immensely in-, 
 creased; it is, dierefore, .peculiarly proper 
 for heating large quantities of matter to a 
 
EFFECTS OF HEAT. 
 
 violent degree, especially if the contact of 
 solid fuel with such matter is incon¬ 
 venient. Flaming fuel is used for this 
 reason, in many operations performed on 
 large quantities of metal or metallic min¬ 
 erals, in the making of glass, and in the 
 baking or burning of all kinds of earthen 
 ware. The potters kiln is a cylindrical 
 cavity, filled from the bottom to the top 
 with columns of ware. The only inter¬ 
 stices are those that are left between the 
 columns; and the flame, when produced 
 in sufficient quantity, pr oves a torrent of 
 liquid fire, constantly flowing up through 
 the whole of those interstices, and heats 
 the whole pile in an equal manner. 
 
 “ Flaming fuel is also proper in many 
 works or manufactories, in which much 
 fuel is consumed, as in breweries, distil¬ 
 leries, and the like. In such works it is 
 evidently worth while to contrive the 
 furnaces, so that heat may be obtained 
 from the volatile parts of the fuel, as well 
 as from the fixed; for when this is done, 
 less fuel serves the pmpose than would 
 
EFFECTS OF HEAT. 
 
 Otherwise be necessary. But this is little 
 attended to, or ill understood, in many of 
 those manufactories. It is not uncom¬ 
 mon to see vast clouds of black smoke 
 and vapour coming out of their vents. 
 
 . “ This happens in consequence of their 
 throwing too large ,a quantity of crude 
 fuel into, the furnace at once. The heat 
 is not sufficient to inflame it quickly, and 
 the consequence is, a great loss of heat 
 
 58. I hope it will not be considered an 
 improper digression, to mention a subject 
 which has lately excited a good deal of the 
 public attention; I allude to the light pro¬ 
 duced from the gas proceeding from the 
 distillation of pit-coal. From the Philo¬ 
 sophical Transactions, it appears that, as 
 far back as the year 1735, it was known 
 as a fact, that coal yields an inflamable 
 gas, but its beneficial application seems to 
 have been reserved for Mr. Murdoch, In 
 the year 1792. The most extensive cot^ 
 
 • Black’s Lectures, vol. i, pages 312—31S. 
 
70 
 
 EFFECTS OF HEAT. 
 
 ton-mill in the kingdom, has been, for 
 several years, lighted up with the gas from 
 coal. The following extract from a peri¬ 
 odical work of extensive circulation *, as 
 giving a summary view of this subject, 
 and as containing some valuable facts 
 respecting fuel, I trust will be acceptable 
 to the reader. But those who wish to 
 pursue the subject, I would refer to the 
 work alluded to, as well as to Mr. Mur¬ 
 doch’s “ Account of the Application of 
 Gas fi'om Coal to Economical Purposes,” 
 published in the Philosophical Transac¬ 
 tions for 1808, and reprinted in Nichol¬ 
 son’s Philosophical Journal, the Philosophi¬ 
 cal Magazine, and the Monthly Magazine 
 for the same year. 
 
 “ Pit-coal exists in this island in strata, 
 which, as far as concerns the himdredth 
 generation after us, may be pronounced 
 inexhaustible; and is so admirably adapted, 
 both for domestic purposes and the uses 
 of the ans, that it is justly regai'ded as a 
 
 •Edinburgh Reyiew, voL aiii. page 47S. 
 
EFFECTS OF HEAT. 
 
 71 
 
 niost essential constituent of our national 
 wealtli. When exposed to heat, as we see 
 it every day in our grates, it is manifestly 
 composed of a fixed base of carbonaceous 
 matter, and a variety of evaporable sub¬ 
 stances, which are driven off in the form of 
 smoke and flame. But, instead of being con¬ 
 sumed in this open way, the coal may be dis¬ 
 tilled, and these evaporable matters collected 
 in proper vessels, and examined. They are 
 then found to contain, besides a consider¬ 
 able quantity of matter, which is condensed 
 by cold into tar and alkaline liquor, an 
 invisible elastic fluid, or gas, which no 
 cold nor affusion of water can condense or 
 absorb. It is a compound of two highly 
 inflamable' gases, which chemists call the 
 light hydrocarbonate, and the heavy hy- 
 drocarbonate, or olefiant gasj and this 
 mixture burns with a very brilliant and 
 beautiful light. It is this gas which fur¬ 
 nishes the flame in our common fires 
 
 “ • There are, in fact, according’ to Mr. Davy, three inflamable 
 gases given out in our fires;—the two we have njentioned, and the 
 gaseous oxide of carbon, which is known by its blue flame. They are 
 all distinctly perceptible; the light bydrocarbonate forms the main body 
 of the flame; the olefiant appears in brilliant jets; and the gaseous 
 
72 
 
 EFFECTS OF HEAT. 
 
 but its beauty is there impaired by the 
 unavoidable alloy of smoky vapour. A 
 separation, however, may be effected by 
 the distilling process, which leaves the 
 pure aerial fluid such as we have described. 
 All the new plans for lighting with coal- 
 gas, proceed upon the principle of purify¬ 
 ing this fluid, collecting it in reservoirs, 
 and distributing it in. tubes. From the 
 furnace where the coal is distilled, a main 
 pipe may convey all the evaporable matter 
 into a large reservoir or gasometer, where, 
 by various means—chiefly, we believe, by 
 washing with water, it may be freed from 
 impurities, and propagated through the 
 tubes in every direction by its own elas¬ 
 ticity. If nothing confine it, it will issue 
 from the .extremities in an equable flow, 
 but still invisible, till a lighted taper be 
 applied^- when it bursts into flame, and 
 continues to bum as long as the gas is 
 supplied. Mr. Accum found, by a com¬ 
 parison of shadows, in the manner sug- 
 
 oxide is occaaonally seen near the root of the fiame, or in contact with 
 the coal It is possible that a small portion of this oxide may mix with 
 prepared gas. 
 
EFFECTS OF HEAT. 73 
 
 gested by Count Rumford, that the light 
 of a gas flame is to that of an equal-sized 
 flame of a candle or lamp as 3 to 1 or, 
 in other words, that to light up a certain 
 space, one gas flame will give as much 
 light as three candles burning with a flame 
 of equal size. The products of the com¬ 
 bustion are, in both cases, the same,— 
 water and carbonic acid gas; but with this 
 material difference, that candles frequently, 
 and lamps always, give out a quantity of 
 smoke and soot; whereas the combustion 
 of the gas is perfect, and leaves no sensible 
 residuum,—nothing that can soil the most 
 delicate white. Its effects on the air of a 
 room are, therefore, less insalubrious than 
 those of a candle, since the only noxious 
 substance it yields is carbonic acid gas; 
 and this it produces in smaller quantity 
 than our common lights. From the in- 
 
 “ • We should have suspected the proportion was over-rated, had 
 not the same accurate experimenters assured us, ‘ that 500 cubic inches 
 of gas, burnt from the orifice of a jet, so as to produce a flame equal 
 in size to that of an ordinary candle, consumed 1076 cubicinches of 
 oxygen gas in the same time that a candle, kept burning in the best 
 possible manner, consumed only 279; and we know, that the intensity 
 of any artificial light depends on the rapidity with which oxygen i» 
 absorbed.’—See Appendix to Report of the Committee, &c. 
 
 K 
 
74 
 
 EFFECTS OF HEAT. 
 
 flamable properties of the gas, explosions, 
 bursting of tubes, and other dangers might 
 be apprehended. But there is no ground 
 for such fears. On the contrary, nothing 
 can be more simple or easy in the man¬ 
 agement. The gas may be confined by a 
 stop-cock with perfect safety, and issued 
 as occasion requires. When it is exhausted, 
 the flame goes out as quietly as the flame 
 of a candle does, when the tallow is spent. 
 
 “ Such are the nature and properties of 
 this curious and beautiful substance, when 
 examined in a small way in the laboratory 
 of the chemist. But it frequently happens, 
 that theories perfectly just and elegant in 
 themselves, and confirmed by experiments 
 on a small scale, with a nice apparatus and 
 skilful management, are yet, when at¬ 
 tempted in the large and wholesale way, 
 utterly incapable of being reduced to prac¬ 
 tice; and thus, many a promising plan has 
 ended with performing nothing. But, in 
 the case before us, there are facts, of the 
 description we want to be collected from 
 difierent quarters, and furnished by indi- 
 
EFFECTS OF HEAT. 
 
 75 
 
 viduals unconnected with each other, which 
 full^ verify the anticipations of theory, and 
 the conclusions of more limited experi¬ 
 ment. 
 
 “ This substance (coke) is the residuum 
 that is found after all the evaporable mat¬ 
 ter has been expelled from the coal by 
 heat. It comes out from the distilling 
 process in large spungy masses, greatly 
 diminished in weight, but increased in 
 bulk nearly one-third. Though somewhat 
 more difficult of ignition than coal, it 
 burns longer, and gives out a steadier and 
 more intense heat. That it should do so, 
 will not appear strange to our chemical 
 readersj (and who is there now, that does 
 not know something of chemistry?) when 
 it is considered that the quantity of mat¬ 
 ter, which, in the combustion of coal, is 
 changed from a solid to a state of elastic 
 fluidity, must necessarily carry off much 
 caloric in a latent state; while the glow 
 of the coke radiates with an intensity un¬ 
 impaired by any demand of this kinri, 
 The same respectable chemist we formerly 
 
76 
 
 EFFECTS OF HEAT. 
 
 mentioned, bears testimony to the supe¬ 
 riority of coke. ‘ I have learned,’ says 
 Mr. Accum*, ‘ that the heat produced by cokc^ 
 
 mahm compared mth that which cm be obtained 
 from coal, is at least as 3 to 2.’ Thus he 
 found, that it required three bushels of coal 
 to distil a given quantity of vrater, and 
 only two of coke. He tried the two sub¬ 
 stances also by combustion, with a certain 
 measure of oxygen gas, by the fusion and 
 the reduction of metals, &c.; and tlie same 
 result was obtained,—a result certainly not 
 unimportant, since it proves that, by being 
 forced to yield the material of a beautiful 
 light, coal is actually improved very con¬ 
 siderably in its power of giving heat. 
 
 “ Before taking leave of Mr. Winsor, we 
 shall present the reader with'the results of 
 his analysis of coal, which, we should have 
 been cautious of admitting among authentic 
 facts, had not the Committee declared, that 
 the experiments were repeated in their pre¬ 
 sence, and that they corroborated Winsor’s 
 
EFFECTS OF HEAT. 
 
 11 
 
 printed statement in the most satisfactory- 
 manner. Two pecks of Newcastle coal,weighing 
 36 lb., produced three pecks ofcoke, weighing 24 
 ll). ^2 02 ., dout Sk IL of oily tar, and ahoui of 
 alkaline liquor-, and, as the only other product 
 was gas, it is concluded that gas constituted the 
 remainder of the weight, amounting nearly to 
 four poundsT 
 
 59. I shall collect here the effect of' 
 several kinds of fuel in producing heat, as 
 given by authorities which have come tm- 
 der my observation, and. afterwards make 
 a comparative abstract of the result. The 
 distillation of water is a simple and satis¬ 
 factory mode of comparing the effects of 
 fuel. 
 
 60. Mr. Dalton says, for the sake of 
 those who are more inimediately interested 
 in the economy of fuel, that the heat given 
 out by the combustion of 1 Ih. of charcoal, 
 and, perhaps, also of pit-coal, is sufficient 
 (if there were no loss) to raise 45 or 50 lbs. 
 of water from the freezing to the boiling 
 temperature; or it is sufficient to convert 
 
18 
 
 EFFECTS OF HEAT. 
 
 7 or 8 /6s, of water into steam. If more 
 than this weight of coal be used, there is 
 a proportionate quantity of heat lost, which 
 ought, if possible, to be avoided *. 
 
 61. In Dr. Black’s Lectures, vol. i. page 
 184, we have the following note; “ 100 
 pounds weight of the best Newcastle coal, when 
 applied by the most judiciously constructed fur¬ 
 nace, will convert about li wine hogshead f of 
 water into steam that supports the pressure of 
 the atmosphere. 
 
 62. By this account, observes Count 
 Rumford, which he (Mr. Kirwan) tells me 
 is foimded on experiments made by Mr. 
 Lavoisier, it appears, that equal quantities 
 of water under equal surfaces, may be 
 evaporated, and consequently equal heats 
 produced- 
 
 By 403 lbs. of coaks, 
 600 — of pit<oal, 
 600 — of charcoal, 
 1089 — of oak, 
 
 S By 17 of coaks, 
 
 10 of pit^coal, 
 40 of charcoal, 
 33 of oak L 
 
 • Dalton’s Chemical Philosophy, page 82. 
 f Equal to 12.63 cubic feet. 
 
 I Rumford’s Essays, toL ii. page 134. 
 
EFFECTS OF HEAT. 
 
 79 
 
 “ From the result of my 20th experiment, 
 it appeared that 20^ lbs. of ice-cold -water 
 might be heated 180 degrees, or made to boil 
 under the mean pressure of the atmosphere, at 
 the level of the surface of the ocean, with the 
 heat generated in the combustion of \ lb. of 
 pine-auood. Computing from the result of 
 this experiment, and from the relative quan¬ 
 tities of heat producible from pine-wood 
 and from pit-coal, it appears that the heat 
 generated in the combustion of \ lb. of pit-coal, 
 would make S6-rj lbs. of ice-cold water boil .—■ 
 Hence it appears, that pit-coal should heat 
 36 times its weight of water, from the 
 freezing point to that of boiling; and as it 
 has been found by experiments, made with 
 great care by Mr. Watt, that nearly times 
 as much heat as is sufficient to heat any 
 given quantity of ice-cold water to the 
 boiling point, is required to reduce that 
 same quantity of water, already boiling hot, 
 to steam; according to this estimation, the 
 heat generated in the combustion of 1 lb. of coal, 
 should be sufficient to reduce very nearly 7 lbs. 
 ef boiling hot water to steam 
 
 •Count Rnmford’s Essays, to), it page 136, 137. 
 
80 
 
 EFFECTS OF HEAT. 
 
 Dr. Crawford found, by an experiment 
 contrived with much ingentuty, and which 
 appears to have been executed with the 
 utmost care, that the heat generated in the 
 combustion of 30 grains of charcoal raised 
 the temperature of 31 lbs. 7 oz. Troy= 
 181.920 grains of water Itw degrees of 
 Fahrenheit’s thermometer, lohen none of the 
 heat generated was suffered to escape. Con¬ 
 sequently, the heat generated in the combus¬ 
 tion of \ lb. of charcoal, would be sufficient to 
 heat 57.608 lbs. of ice-cold water 180 degrees, 
 or to make it boil; for 3157.9 grains of char¬ 
 coal are to 181.920 grains of water, as 1 
 of charcoal to 57.608 lbs. of water. 
 
 From the result of Mr. Lavoisier’s ex¬ 
 periments, it appeared that the quantities 
 of heat generated in the combustion of 
 equal weights of charcoal and dry oak, 
 are as 1089 to 600. Hence we may con¬ 
 clude, that equal quantities of heat are gen¬ 
 erated by 1 lb. of charcoal and 1.815 lbs. 
 of oak; consequently, that the heat gen¬ 
 erated in the combustion of 1.815 lbs. of 
 oak, would heat 57.608 lbs. of ice-cold 
 
EFFECTS OF HEAT. 
 
 81 
 
 water,—or 1 lb. of oak, 31.74 lbs. of ice- 
 cold water 180 degrees, or cause it to boil; 
 were no part of the heat generated in the com- 
 hustion of fuel lost *. 
 
 63. “ The comparative examination of 
 the intensity of the heat produced by burning 
 charcoal and charred turf proves that the heat 
 of the latter is (to that of the former) nearly 
 in the proportion of three to one f. 
 
 64. “ Ml*. Watt finds, that it requires 
 
 eight feet surface of boiler to be exposed 
 to fire, to boil off one cubic foot of water 
 per hour, and that a bushel or 84 lbs. New¬ 
 castle coal., so applied, will boil off from eight 
 to twelve cubic feet J. - '■ 
 
 65. “ The heat expended in boiling oif 
 a cubic foot of water, is about six times as 
 much as would bring it -to a boiling heat 
 
 • Count Rumford’s Essay, vol. ii. page 139, 140. 
 f “ Inquiry into the comparative intensity of heat produced by the 
 combustion of charcoal and charred turf,” in the Memoirs of the Acad¬ 
 emy of Sciences of Paris. Repertory of Arts, vol. v. p. 419. 
 
 I,'”’’ 
 
82 
 
 EFFECTS OF HEAT. 
 
 from the medimn temperature, {55°) in 
 this climate*.” 
 
 66. Mr. Watt, I believe, for his steam- 
 engines, in situations where wood is the 
 fuel employed, allows three times the 'weight 
 of ‘wood, that he does of Neu'castle coal, 
 
 67. Newcastle coal produces much more 
 heat than the generality of Scorch coal. A 
 bushel of Ne-wcastle coal, 'which 'weighs \of a 
 cwt. is reckoned to produce as much heat as a 
 cwt. of Glasgow coal, 
 
 68. Small coal or culm, is much used 
 for steam-engines. From repeated trials, 
 made in the neighbourhood of Glasgow, 
 it requires just double the 'weight of culm that 
 it does of coal to produce the same heat. At 
 the prices in 1808, the cost of culm was 
 to that of coal, supplying the same work 
 as 12 is to 14, thus producing a saving of 
 4 by the use of culm. 
 
 * En. Brit. Supplement. 
 
EFFECTS OF HEAT. 
 
 83 
 
 69. “ A wax candle i of an inch in 
 diameter, loses a grain of its weight in 37 
 seconds, and consumes about three grains, 
 or 9 cubic inches of oxygen gas, produc¬ 
 ing heat enough to raise the temperature 
 of about 15000 grains of water a singly 
 degree. According to the experiments of 
 Mr. Lavoisier and Mr. Laplace, the com¬ 
 bustion of 10 grains of phosphoras, 
 requires the consumption of 15 grains of 
 oxygen; the combustion of 10 grains of 
 charcoal 26, and of hydrogen gas 56; and, 
 by the heat produced during the combustion 
 of a pound of phosphorus, 100 pounds of 
 ice may be melted; during that of a pound 
 of charcoal, 96l; of hydrogen gas, 2955; of 
 wax, 133; and of olive oil, 149; and during 
 the deflagration of a pound of nitre, with 
 about one-sixth part of its weight of char¬ 
 coal, 12 pounds of ice may be melted*.” 
 
 70. The following table contains a 
 comparative abstract of the effect of sev¬ 
 eral kinds of fuel in producing heat. 
 
84 
 
 EFFECTS OF HEAT. 
 
 The numbers in the fourth column, point 
 out the Articles in this Essay which con¬ 
 tain the authority upon which the abstract 
 is made, or on which the proportions are 
 calculated. 
 
 2. 3. 4. 
 
 
 .i-sj 
 
 sy 
 
 111 
 
 Jii 
 
 1" 
 
 -s g 
 k 
 
 
 1 lb. charcoal or 
 
 54toS0 
 
 7or6 
 
 60 
 
 Dalton. 
 
 1 lb. of piKoal, 
 
 36-,^ 
 
 7. 
 
 62 
 
 Count Rumford. 
 
 1 lb. charcoal, 
 
 57.608 
 
 10.9 
 
 62 
 
 Crawford. 
 
 1 lb. drj- oak, 
 
 31.7 
 
 
 62 
 
 Lavoisier. 
 
 1 lb. of pine-wood. 
 
 20.1 
 
 
 62 
 
 Count Rumford. 
 
 1 lb. of Newcastle coal. 
 
 
 6. 
 
 64. 
 
 Watt. 
 
 lib. do. „ do. 
 
 
 
 61 
 
 Black. 
 
 1 lb. do. do. 
 
 
 6.25 
 
 63 
 
 Watt. 
 
EFFECTS OF HEAT. 
 
 85 
 
 SECTION V. 
 
 Of the Motion of Heat. 
 
 71. The temperature of bodies being 
 liable to perpetual fluctuation, to deter¬ 
 mine the nature of the motion of heat in 
 the same body, and in its passage from 
 one body to another, arising from its 
 incessant tendency to an equilibrium, 
 becomes of much practical importance. 
 Dr. Ingenhouse to show the relative con¬ 
 ducting power of the different metals, 
 made this simple experiment;—he took 
 equal straight pieces of stout wire of the 
 different metals, drawn through the same 
 hole and of the same lengths, and dipping 
 them into melted wax. He then held 
 one end, of each of these wires in boiling 
 water, and observed how far the coating 
 of wax was melted by the heat commun¬ 
 icated through the metal, and with what 
 celerity the heat passed. 
 
 72. The property by which bodies 
 receive, and part with heat when in com- 
 
86 EFFECTS OF HEAT, 
 
 munication with others of a different tem¬ 
 perature, is termed their conducting power. 
 Those which have their temperature 
 quickly altered by communication with 
 
 Other bodies, are said to be better con¬ 
 ductors of heat, than those which receive 
 and part with it more slowly. 
 
 73. The power of conducting heat, 
 varies greatly according to the nature of 
 the subject. In general, it may be re¬ 
 marked that dense bodies are the best 
 conductors of heat, and tliat those which 
 are more rare conduct it very imperfectly. 
 The metals, for instance, are good conduc¬ 
 tors. Earthy substances conduct more 
 slowly. Wood is a very imperfect conduc¬ 
 tor. Hair, fur, feathers, &c. which form 
 the covering of animals, are still inferior 
 in their conducting power. The same 
 matter in its different states of aggregation, 
 differs in this property. Thus an iron bar 
 or an iron plate is a much better conduc¬ 
 tor than iron filings, and wood than saw¬ 
 dust. 
 
EFFECTS OF HEAT. - 
 
 8*7 
 
 *74. But though these experiments were 
 very ingenious and simple, and, perhaps,' 
 srifficiently accurate for a great variety of 
 practical purposes, yet philosophers, when 
 the truth can be''more nearly ascertained, 
 are not satisfied with these approximations. 
 Professor Leslie described to me an appar¬ 
 atus, which seems well calculated for this 
 purpose, but which he had not then ap¬ 
 plied. I hope, however, he will soon 
 favour the public with the result of his 
 inquiries on this subject. 
 
 Dr. Ingenhouse, from his experiments, 
 concluded, “ that the conducting powers 
 of the metals which he examined, were in 
 the following order *. 
 
EFFECTS OF HEAT. 
 
 Next to metals, stones seem to be the 
 best conductors; but this property varies 
 considerably in different stones. Bricks 
 are much worse conductors than most 
 vStones. 
 
 “ Glass seems not to differ much from 
 stones in its conducting power. Like 
 them, it is a bad conductor. This is the 
 reason that it is so apt to crack on being 
 suddenly heated or cooled. One part of 
 it, receiving or parting with its caloric 
 before the rest, expands or contracts, and 
 destroys the cohesion. 
 
 “ Next to these come dried woods. Mr. 
 Meyer* has-made a set of experiments on 
 the conducting power of a considerable 
 number of woods. The result may be 
 seen in the following Table, in which 
 die conducting power of water is sup- 
 
EFFECTS OF HEAT. 
 
 89 
 
 JBODIES. 
 
 Water.. 
 
 Diaspyrus ebenum, or ebony .... 
 
 Pyrus malus, or the common apple-tree - 
 Praxinus excelsior, or the ash-tree . . - 
 ■Fagus sylvatica, or the beech tree - - - 
 Carpinus betulus, or common hornbeam - 
 Prunus domestica, or common plum tree - 
 
 Ulmus, or the elm. 
 
 Quercus robur pendunculata, or common m. 
 
 Pyrus communis, or the common pear tree 
 Betula alba, or the common birch tree 
 Quercus robur sessilis, the low growing oak 
 Pinus picea, or yew leaved fir - - - - 
 Betula alnus, or the alder tree - . . - 
 Pinus sylvestris, or the wood pine . . - 
 pinus abics, or the European spruce fir - 
 Tilea Europtea, or the European lime tree 
 
 “ Charcoal is also a bad conductor: 
 According to the experiments of Morveau, 
 its conducting power is to that of fine 
 sand :: 2 : 3 *. Feathers, silk, wool, and 
 hair, are still worse conductors than any 
 of the substances yet mentioned. This is 
 the reason that they answer well for 
 articles of clothing. They do not allow 
 the heat of the body to be carried off by 
 
 • Ann. de Chim. irvi. 225. 
 
 M 
 
 =1.00 
 
 =2.17 
 
 =3.23 
 
 =3.25 
 
90 
 
 EFFECTS OF HEAT. 
 
 the cold external air. Count Rumford 
 has made a very ingenious set of experi¬ 
 ments on the conducting power of these 
 substances *. He ascertained that their 
 conducting power is inversely as the fine¬ 
 ness of their texturei 
 
 “ The conducting power of liquid bodies 
 has not been examined with any degree of 
 precision. I find, by experiment, that the 
 relative conducting powers of mercury, 
 water, and lintseed oil, are as follows: 
 
 Eq:^al Bull,. 
 
 Water.=1 
 
 Mercuiy ----- =2 
 Lintseed oil - . . - =1.111 
 
 11 . Equal Weights, 
 
 Water.=1 
 
 Mercury ----- =4'.8 
 
 Lintseed oil - . - - =1.085 
 
 “ As bodies conduct caloric in conse- 
 quenefe of their affinity for it, the inequality 
 
 of their conducting power is a demonstra- 
 
 • Phil. Trans. 1792. 
 
EFFECTS OF HEAT. 
 
 91 
 
 rion that their affinities for caloric are also 
 unequal. It is probable that their affinity 
 for caloric is in all cases the inverse of 
 their conducting power. If, therefore, we 
 were in possession of the relative conduct¬ 
 ing powers Qf bodies, the inverse of that! 
 would give us the affinities in absolute 
 numbers. Thus the affinity of 
 
 Water is ... =1 ... =1 
 
 Mercury - - - - - =0.208 
 
 Lintseed oil - - —t.wt " ‘ * 
 
 75. “ When a fluid is heated at its 
 surface, the heat gradually and slowly 
 descends in the same manner as along a 
 solid; and fluids seem to have a difference 
 in. their conducting power, analogous to 
 that of solids. But when the heat is 
 applied to the bottom of a vessel contain¬ 
 ing a fluid, the case is very different, the 
 heated particles of the fluid, in conse¬ 
 quence of their dijninished specific 
 gravity, form an ascending current, and 
 rise to the surface, communicating a 
 
92 
 
 EFFECTS OF HEAT. 
 
 portion of heat in their ascent to the 
 contiguous particles, but still retaining 
 a superiority of temperature; so that the 
 increase of temperature in the mass is 
 first observed at die surface, and is 
 constantly greatest there till commence¬ 
 ment of ebullition in liquids, at which 
 period the temperature is uniform. The 
 conducting power of fluids then arises 
 from two distinct sources: the one is the 
 same as solids, namely, a gradual progress 
 of theheat from particle to particle,exclusive 
 of any motion of the particles themselves; 
 die other arises from the internal motion 
 of the pai-tlcles of the fluid, by which the 
 extremes of hot and cold are perpetually 
 brought into contact, and the heat is thus 
 diffused widi great- celerity. The latter 
 source is so much more effectual than the 
 former, that some have been led, though 
 widiout sufficient reason, to doubt the 
 existence of die former, or that fluids 
 do convey heat in the same manner as 
 solids. 
 
EFFECTS OF HEAT. 93 
 
 “ Nothing appears then, but that the 
 communication of heat from particle to 
 particle, is performed in the same way in 
 fluids as in solids; the rapidity of its 
 diffusion in fluids, is to be ascribed to 
 a hydrostatical law. But there is another 
 method by which heat is propagated 
 through a vacuum, and through elastic 
 fluids, which demands our particular 
 notice. By this we receive the heat of 
 the sun, and by this, when in a room, we 
 receive the heat of an ordinary Are. It is 
 called the radialion of heat; and the heat so 
 propelled, is called radiant heat 
 
 76. “ The activity of these rays, says 
 Count Rumford, may be shown in dif¬ 
 ferent ways, but in no way, in a more 
 striking manner, than by the following 
 simple experiment. When the fire burns 
 bright upon the hearth, let the arm be ex¬ 
 tended in a straight line towards the centre 
 of the fire, with the hand open, and all the 
 fingers extended and pointing to the fire. 
 
94 EFFECTS OF HEAT. 
 
 If the hand is not nearer the fire than the 
 distance of two or three yards, except the 
 fire be very large indeed, the heat will 
 scarcely be perceptible; but if without 
 moving the arm, the wrist be bent upwards, 
 so as to present the inside, or flat of the 
 hand perpendicular to the fire, the heat 
 will not only be very sensibly felt, but if 
 the fire be large, and if it burns clear and 
 bright, it will be found to be so intense 
 as to be quite insupportable 
 
 77. “ Till lately, we have been used to 
 consider the light and heat of the sun, as 
 
 the .same tiling. But Dr. Herschel has 
 shown, that there are rays of heat pro¬ 
 ceeding from the sun, which are separable 
 by a prism, from the rays of light; they 
 are subject to reflection like light and to 
 refraction, but in a less degree, which is 
 the cause of their separability from light. 
 The velocity of radiant heat is not known, 
 but it may be presumed to be the same 
 as that of light, till something appears 
 
 • Riunford’s Essays, • 
 
EFFECTS OF HEAT. 
 
 95 
 
 to the contrary. An ordinary fire of red 
 hot charcoal, or, indeed, any heated.body, 
 radiates heat, which is capable of being 
 reflected to a focus, like the light and heat 
 of the sunj but it should seem not to be 
 of sufficient energy to penetrate glass, or 
 other transparent bodies, so as to be re¬ 
 fracted to an efficient focus *. 
 
 78. “ Dr, Hofiinann, appears to have 
 been the first that collected the invisible 
 heat of a stove into a focus, by the reflec¬ 
 tion of one or more concave mirrors. 
 Buffon, Saussure, Pictet, and Mr. King, 
 made afterwards similar experiments on 
 the heat of a plate of iron, and of a vessel 
 of boiling water f,” 
 
 79. Professor Lesslie, has lately ascer¬ 
 tained and published in his “ Inquiry on 
 Heat,” several new and important facts, 
 relative to the radiation f of heat. Some 
 
 • Dalton, p. 101 and 103. f Young’s Nat. Phil. p. 637. 
 
 ^ Professor Lesslie calls this the pulsation of heat. The term 
 radiation, not being applicable according to his theory. 
 
96 
 
 EFFECTS OF HEAT. 
 
 of the principal of these facts, it will be 
 proper here to mention; but I shall first 
 endeavour to give some idea of the instru¬ 
 ments which he used. 
 
 These were concave mirrors of tin-plate, 
 about 14 inches in diameter, and tin-plate 
 cannisters of different sizes, one side of 
 which was kept clean and bright, the 
 opposite was covered with writing paper, 
 
 or painted with lamp, black; the other 
 
 sides were left for miscellaneous service. 
 With these was employed an ingeniously 
 constructed and delicate air thermometer, 
 than which nothing could be more simple 
 and commodious, and for the invention of 
 which, the philosophical world are indebted 
 to Mr. Lesslie. It is thus constructed. 
 
 80. “ Two glass tubes of unequal 
 lengths, each terminating in a hollow ball, 
 and having their bores somewhat widened 
 at the other ends, a small portion of 
 sulphuric acid tinged with carmine being 
 introduced into the ball of the longer 
 tube, are joined together by the means 
 
EFFECTS OF HEAT. 
 
 97 
 
 1 of a blow-pipe, and afterwards bent into 
 nearly the shape of the letter U, the one 
 flexure being made just below the joining, 
 where the small cavity facilitates the adjust¬ 
 ment of the instriunent, which, by a little 
 dexterity, is performed by forcing with 
 the heat of the hand a few minute globules 
 of air from the one ball into the other. 
 The balls are blown as equal as the eye 
 can judge, and from four-tenths to seven- 
 I tenths of an inch in diameter. The tubes 
 ; are such as are drawn for mercurial 
 thermometers, only with wider bores; 
 that of the short one, and to which the 
 scale is affixed, must have an exact calibre 
 of a fiftieth or a sixtieth of an inch; the 
 bore of the long tube need not be so re¬ 
 gular, but should be visibly larger, as the 
 coloured liquor will then move quicker 
 under any impression. Each leg of the 
 instrument is from three to six inches in 
 height, and the balls are from two to four 
 inches apart. The lower portion of the 
 syphon is cemented at its middle to a 
 slender wooden pillar inserted into a 
 round or square bottom, and such that 
 N 
 
EFFECTS OF HEAT. 
 
 the balls stand on a level with the centre 
 of the specnlnm. A moment’s attention 
 to the construction of this instrument will 
 satisfy us that it is affected only by the 
 difference of heat in the corresponding 
 balls, and is calculated to measure such 
 difference with peculiar nicety. As long 
 as both balls are of the same temperature, 
 whatever this may be, the air contained 
 in the one will have the same elasticity as 
 that in the other, and consequently the 
 intercluded coloured liquor, being thus 
 pressed equally in opposite directions, 
 must remain stationary. But if, for in¬ 
 stance, the ball which holds a portion of 
 the liquor be warmer than the other, the 
 superior elasticity of the confined air will 
 drive it forwards, and make it rise in the 
 opposite branch above the zero, to an 
 elevation proportional to the excess of 
 elasticity or of heat. The interval be¬ 
 tween freezing and boiling water being 
 distinguished into an hundred equal parts, 
 called centigrade, each of these subdivided 
 decimally, constitute the degrees which I 
 employ, and which, following up the same 
 
BFFECTS OF HEAT. 99 
 
 system of nomenclature, would be termed 
 milligrade". See Fig. 6, Plate 1. 
 
 81. “ I may notice a simple improve¬ 
 ment, or modification of the differential 
 thermometer, which fits it for estimating 
 with nice precision, the intensity of the 
 diffuse radiations of heat. It has still the 
 form represented by Fig. 2,* ofily the 
 ball of the graduated stem is completely 
 gilt or enamelled with gold. But-the two 
 balls exposed to the same influence, will 
 now receive very different impressions, 
 and the excess of energy, which the in¬ 
 strument marks, must, therefore, amoimt 
 nearly to seven-eighths of the whole vi¬ 
 bratory tide. Hence, it will measure the 
 quantities of heat that are continually 
 thrown from the fire into a room. We 
 can thus calculate, with equal ease and 
 certainty, the ralative advantages arising 
 from various constructions of chimniesf,” 
 
 • Mr. Leslie’s I’ig. 2, is the same as 6, Plate 1 j of this Essay. 
 
 ILeslie on Heat, p, 9*11, 561. 
 
100 
 
 EFFECTS OF HEAT. 
 
 82. Mr. Leslie has also applied this 
 instrument, in a very simple and ingen¬ 
 ious manner, by covering one of the balls 
 with thin silk, and moistening it to act 
 ■as a hygrometer, or instrument for mea¬ 
 suring the" degree of moisture in the 
 atmosphere. An instrument of the kind 
 has long been wanted in the cotton and 
 other manufactures. Respecting Mr, Dal¬ 
 ton’s hygrometer, as also those of Bereze- 
 lius, and Mr. Gough, the reader will find 
 information in the Philosophical Magazine, 
 vol. xxxiii. p. 39,17Y. 
 
 83. The following are some of the 
 principal facts, which were discovered or 
 confirmed by Professor Leslie. 
 
 1st, If a given vessel be filled with hot 
 water, the quantity of heat which radiates 
 from it, depends chiefly upon the nature 
 of the exterior surface of the vessel. 
 Thus, if a canister of tinned iron be the 
 vessel, then a certain quantity of heat 
 radiates from it; if the said vessel be co¬ 
 vered with black paint, paper, glass, &c. 
 
EFFECTS OF HEAT. 101 
 
 it will then radiate 8 times as much heat 
 in like circumstances *. 
 
 84. 2d, “ If the bulb of the thermometer 
 be covered with tin-foil, the Impression of 
 the radiant heat is only ^ of that upon the 
 glass surface. 
 
 85. 3d, “A metalic mirror reflects 10 
 times as much heat from an ordinary fire, 
 or from any heated body, as a similar 
 glass mirror does. This last is found to 
 reflect the heat from its anterior surface, 
 and not from the quick-silvered one, 
 vsrhich is the most essential in reflecting 
 solar light, and heat. Here then is a 
 striking difference between solar and 
 culinary heat. 
 
 • When one side of a tin-plate canister was « 
 another with writing paper, a third with glass, i 
 or covered with tin-foil, the diiferential then 
 Black side was exposed to the speculum to - 
 
 Glass - - - - . 
 Tin-plate, or tin-foil 
 
102 
 
 EFFECTS OF HEAT. 
 
 “ From these facts it appears,' that 
 metals and other bodies which are emi¬ 
 nently disposed to rejiect radiant heat, are 
 not disposed to absorb it in any remark¬ 
 able degree; whereas black paint, paper, 
 glass, &c. are disposed to absorb it, and 
 consequently to radiate it again in proper 
 circumstances.” 
 
 86. 4th, “ The heat radiating from hot 
 water, does not seem capable of being 
 transmitted through glass like the solar 
 heat. 
 
 87. 5th, “ When a heated body is 
 whirled through the air, the additional 
 cooling effect is directly proportional to 
 the velocity 
 
 88. Mr. Dalton infers from his experi¬ 
 ments, contrary to the results obtained 
 by Mr. Leslie, that the same law of 
 progressive cooling (viz. that “ the tempera¬ 
 ture descends in geometrical progression to equal 
 
 
 a. Phil, pages, lOS, : 
 
EFFECTS OF HEAT. 
 
 103 
 
 increments of time*'') applies to a metalic 
 as well as to a vitreous surface f. The 
 surface, however, materially affects the 
 whole time which is occupied in cooling. 
 
 89. “ After a long and intricate, but 
 ingenious investigation, Mr. Leslie finds 
 the’ cooling power of the air upon a hol¬ 
 low sphere, six inches in diameter, and 
 filled with boiling water, to be as follows: 
 namely, in each minute of time, the fluid 
 loses the following fractional parts of its 
 excess of temperature, by the t/iree distinct 
 sources if refrigeration in the air under¬ 
 mentioned. 
 
 “ By abduction, that is, the proper con¬ 
 ducting power of air, the 524th. 
 
 “ By recession, that is, the perpendicular 
 current of air excited by the heated body, 
 the hx 21715th. 
 
 f “ The term surface is used throughout this discourse, in its physical 
 and not its mathematical acceptation. I employ it to signify a stratum 
 of matter of a certain finite depth, yet of such extreme tenuity as almost 
 
104 EFFECTS OF HEAT. 
 
 “ By pulsation^ or radiation^ the 2533d part 
 from a metalic surface, and eight times as 
 much, or the 317th part from a surface of 
 paper. It should be observed, that Mr. 
 Leslie contends that air is instrumental in 
 the radiation of heat, which is contrary to 
 the received opinion 
 
 In the above fractions, Mr. Dalton does 
 not acqtuesce, and after detailing his own 
 experiments, he proceeds as follows: 
 
 “ It will be proper now to inquire into 
 the cause of the difference in the times of 
 cooling, arising from the variation of 
 surface. Mr. Leslie has shown the sur¬ 
 face has no influence upon the time of, 
 cooling, when immersed in water; it 
 should seem then, that the difference of 
 surfaces in the expenditure of heat, arises 
 from their diffferent powers of radiation 
 solely; indeed, Leslie has proved by direct 
 experiments, that the heat radiating from a 
 vitreous or paper surface, is 8 times as 
 
EFFECTS OF HEAT. 105 
 
 great, as that from a metalKc surface. 
 Taking this for granted, we can easily 
 find the portions of heat dispersed by 
 radiation, and conducted away by the 
 atmosphere. For let 1 denote the quan¬ 
 tity of heat conducted away by the at¬ 
 mosphere, from a vitreous or metallic 
 surface, in any given small portion of 
 time, and x the quantity radiated from a 
 metallic surface in the same timej then 8 x 
 will be the quantity radiated from a vitre¬ 
 ous surface in that time; and from the 
 result of the last experiment we shall have 
 2:3:: l+x : 1 + 8 x-, whence 2 + 16 »= 
 3+3 X, and x=-^‘, this gives liV for the 
 whole heat discharged by metal, and li^r 
 for that discharged by glass in the same 
 time, where the unit expresses the part 
 conducted, and the fraction the part radi¬ 
 ated. That is, from a metallic surface, 13 
 parts of heat are conducted away by the 
 air, and 1 part radiated; from a vitrequs 
 surface, 13 parts are conducted, and 8 
 parts radiated, in a given time. 
 
 O 
 
106 
 
 EFFECTS OF HEAT. 
 
 “ The quantity of heat discharged by 
 radiation, from the most favourable sur¬ 
 face, therefore, is probably not more than 
 4 of the whole, and that conducted away 
 by the air not less than .6—Mr. Leslie, 
 however, deduces .57 for the former, and 
 .43 for the latter, because he found the 
 disproportion in the times of cooling of 
 vitreous and metallic surfaces, greater 
 than I find it in the lower part of the 
 scale.” 
 
 “ The obvious consequences of this 
 doctrine, in a practical sense, are;” 
 
 “ 1st, In every case where heat is re¬ 
 quired to be retained as long as possible, 
 the containing vessel should be of metal, 
 with a bright clear surface.” 
 
 “ 9d, Whenever heat is required to be 
 given out by a body with as much celer¬ 
 ity as possible, the containing vessel if of 
 metal, ought to be painted, covered with 
 paper, charcoal, or some animal or vegi- 
 table matter; in which case the heat given 
 
EFFECTS OF HEAT. 
 
 107 
 
 eut, will be 3 parts for 2 from a metallic 
 surface For it is to be recollected, that 
 the nature of the surface affects only that 
 part of the heat which is radiated. The 
 other two causes of. refrigeration, called, 
 by Mr. Leslie, abduction and recession, or 
 which come together under the more 
 usual name of combined heat, remain the 
 same whatever be the nature of the 
 surface. 
 
 90. Mr. Leslie, in an early part of his 
 inquiry, having, as we saw (Art. 83.) ascer¬ 
 tained that bodies differ widely in their 
 power of projecting, absorbing, and re¬ 
 flecting heat, instituted a set of experi¬ 
 ments, with a view to ascertain the limits 
 of this variation. From these experiments, 
 he found that the chemical qualities of the 
 heating surface, have a considerable influ¬ 
 ence, as will appear from the following 
 summary of the results of his experi¬ 
 ments. 
 
 • Dalton’t Chem. PhU. IIS, IIS, 117. 
 
108 
 
 EFFECTS OF HEAT. 
 
 The standard effect of a coat of lamp-black being - 100 
 
 The effect of bright surface of tin.12 
 
 Iron or steel is as----- ----- - IS 
 Mercury above -.20 
 
 All oxydes act more powerfully as they 
 recede from a metallic state. 
 
 Clean lead, but rough, being as-- - ----19 
 
 Lead tarnished by exposure to the air - - - - - 45 
 
 Black lead or plumbago - -- -- -- -- -75 
 Red lead, or Tniniiim as - -- -- -- --80 
 
 Dry size, or isinglass - -- -- -- -- - 80 
 
 Sealing wax amd rosin are nearly equal to paper, which is - 98 
 Ice.'- 85 
 
 The polish^ where not naturally great, 
 diminishes its action. Thus, tin-:plate 
 when hammered, (which Mr. Leslie calls 
 planished tin,) its power to propagate heat 
 is only half that of ordinary tin-plate. 
 The roughening of glass, however, does 
 not increase its power of projecting heat. 
 
 That of tin is doubled by covering it 
 vrith stria or furrows made in one direc¬ 
 tion, by a file or toothed-plane. This 
 remarkable effect cannot be owing to the 
 
EFFECTS OF HEAT. 
 
 109 
 
 greater surface exposed, because the in¬ 
 crease of surface is exactly counteracted 
 by the increase of obliquity, according to 
 a law which Mr. Leslie established by 
 experiment; and, besides, it is found that 
 cross furrows by striating the stuface in 
 the other direction, nearly destroys the 
 effect of those first made *. 
 
 The thickness of the radiating surface 
 has a great influence on its powers of 
 action, a thin film of isinglass produces a 
 radiation as 26, a thick film as 42, when 
 the thickness exceeds the thousandth part 
 of an inch, any subsequent increase does 
 not augment its action. 
 
 Mr. Leslie is of opinion, that these 
 differences in projective power, may be 
 resolved into the variations of the bodies, 
 as to hardness and softness, and shows 
 that the addition of moisture and still 
 more of a mucilaginous substance, con¬ 
 siderably augments the action of 'a sur¬ 
 face painted black. 
 
110 
 
 EFFECTS OF HEAT. 
 
 Mr. Leslie doubts whether the quality 
 of colour exerts any influence at all, in 
 modifying the projective and absorbent 
 powers of bodies. 
 
 The various reflecting powers of differ¬ 
 ent surfaces, bears some inverse ratio to 
 their absorbent and projective powers, 
 although many circumstances occur to 
 prevent this ratio from being expressed 
 by one universal law. 
 
 91. Mr. Leslie having investigated the 
 various circumstances which affect the 
 progress of the cooling of bodies, when 
 the enclosing boundary is considered a 
 mere physical surface^ (Art. 88.) but where 
 the siuface' of a body is defended by a 
 covering of slow conducting materials, 
 the process of refrigeration, is retarded in 
 proportion to the thickness of the exterior 
 coat. On this principle depends the utility 
 of cloathing, whether natural or artificial, 
 also that of covering steam tubes with 
 slow conducting materials to prevent the 
 dissipation of heat. But it requires a 
 
EFFECTS OF HEAT. Ill 
 
 considerable thickness of such materials, 
 to counteract the effect of the physical sur¬ 
 face in propagating heat. Thus, Mr. 
 Leslie informs me, that he found it re¬ 
 quired three plies of flannel to overcome 
 its radiating power. 
 
 92. “ A fluid of such extreme rarity as 
 air, if confined round a heated body, must 
 like those , spongy substances, have a 
 
 decided influence to retard the operation 
 of cooling. And this property is most 
 distinctly perceived, though on a very 
 limited scale. If a series of hollow- 
 cylindrical vessels be constructed of very 
 thin brass, to fit into one another like a 
 nest of boxes, the first or smallest, filled 
 with boiling water, and with a fine ther¬ 
 mometer inserted, being enclosed in each 
 of the rest consecutively, according to the 
 order of their width, and kept equally 
 separate from the sides and bottom, by 
 resting against protuberant points or a 
 slender chequered ring; on plunging the 
 canister with its adapted case, in a tub 
 ®f water, the rate of cooling will be found 
 
112 
 
 EFFECTS OF HEAT. 
 
 at every successive trial, regularly t« 
 diminish till the space of intercluded air 
 comes to exceed a quarter of an inch, when 
 the effect will be reduced to about a si5c- 
 teenth part. Beyond this limit scarcely 
 any farther decrease is observed, there 
 now being room sufficient to allow that 
 active fluid to develope its mobihty, 
 which fully compensates for the increas¬ 
 ing distance of communication. A limit 
 so narrow, must evidently preclude the 
 great majority of instances that would 
 occiu:. The property of confined air to 
 retard the progress of cooling, is, there¬ 
 fore, founded on a principle not quite 
 obvious, and not hitherto explained. By 
 employing a series of concentric cases, or 
 septa, this effect is wonderfully height¬ 
 ened. Yet a subject in itself so curious, 
 and of such vast importance in the econ¬ 
 omy of heat, has been generally over¬ 
 looked, or only treated in a vague and 
 superficial manner. As I purpose to 
 consider it with some attention, 1 shall, 
 for the sake of clearness, divide it into 
 three branches: 1st, when the‘surface of 
 
EFFECTS OF HEAT. 118 
 
 the internal canister, and its several cases 
 are metallic; 2d, When those surfaces are 
 all painted, or consist of glass; and SM, 
 when they are composed partially of both 
 sorts,. 
 
 93. “ 1st, When all the surfaces by 
 which the included or exterior air is 
 bounded, are metallic. 
 
 “ Suppose the canister so large that its 
 surface may be regarded as equal to that 
 of the exterior case, which is separated 
 from it, only by a narrow space. After 
 an equilibrium is attained, the case will 
 receive and discharge heat exactly in the 
 same proportion; it must, therefore, be 
 just as much hotter than the external, as 
 it is colder than the included air. But 
 this confined portion, will have evident¬ 
 ly the mean temperature of its bound¬ 
 ing sides. Consequently, reckoning the 
 heat of the room as a standard, the tem¬ 
 perature of the outer case, must be equal 
 to half the difference between itself and 
 the temperature of the canister, or equal 
 
114 
 
 EFFECTS OF HEAT. 
 
 to one-third of this whole quantity. 
 Hence, the canister under the shelter of 
 its case, will cool three times slower than 
 if it were exposed naked. Thus, 'v^hen 
 the central heat is 30°, that of the exterior 
 surface will be 10°, and their arithmetical 
 mean, or 20°, will be the temperature of 
 the confined stratum of air. Therefore, 
 the rate of internal Communication which 
 cools the one surface in the same degree 
 as it heats the other, will be as 10°, or 
 equal to the discharge into the free sur- 
 rotmding atmosphere. 
 
 “ Imagine a second case to be now 
 added. The mean temperature of the air 
 which that contains, is equal to its differ¬ 
 ence from 'the mean temperature of the 
 mr included within the first case; and 
 either of these measures is equal to half 
 the excess of the central heat above this 
 last mean. Hence, the outmost case will 
 have only one-fifth part of the tempera- 
 mre of the canister; and, consequently, by 
 the intervention of a double case, its rate 
 of cooling is diminished five times. For 
 
EFFECTS OF HEAT. 115 , 
 
 the sake of illustration, let the temperature 
 of the central mass be 25°, then that of 
 the first case will be 15°, and that of the 
 second case 5°, the mean temperature of 
 the inner stratum of air will be 20°, and 
 that of the outer one 10°, the surface of 
 the canister will regularly discharge a 
 portion of heat as 5°, the next septum will 
 receive and deliver the same to the con¬ 
 tiguous air; and the external case will 
 absorb this portion, and finally discharge 
 it into the air of the apartment. 
 
 “ Pursuing the same mode of reasoning, 
 it would be easy to show, that, with three 
 concentric cases, the canister would cool 
 seven times more slowly; and with four 
 such cases, nine times more slowly. In 
 general, .the degree of diminution is equal 
 to double the ntunber of cases increased 
 by one, or the number of surfaces con¬ 
 cerned: it is hence represented by the 
 progression of the odd numbers, 3, 5, 7, 
 9, 11, 13,&c. 
 
116 
 
 EFFECTS OF HEAT. 
 
 “ This result will appear sufficiently 
 accurate when the canister is of consid¬ 
 erable size, and the cases not too widely 
 disjoined; for instance, if the canister 
 exceeds a foot in diameter, and the inter¬ 
 vals between the cases are each of them 
 not more than half an inch *. 
 
 EXPERIMENT. 
 
 “ A cylindrical canister of planished 
 tin, two inches in diameter and equal 
 height, filled with boiling water, took 
 117' to cool, from 30° to 10°; but en¬ 
 closed within a similar canister of fom' 
 inches in diameter, it required 176' to 
 make the same descent. Another cylin¬ 
 drical canister of four inches, and which 
 took 156' to cool from 20° to 10°, re¬ 
 quired 356', when cased with a similar 
 one of five inches; yet, the interval being 
 filled with flour, the effect was performed 
 in 324'. And a square canister of three 
 inches, that cools from 20° to 10° in 117', 
 took 335' to perform the same effect, after 
 
 • Leslie on Heat, pages 373—378. 
 
EFFECTS OF HEAT. 11*7 
 
 it was enclosed within two similar cases 
 of four and five inches 
 
 94. “ 2d, The next division of the pro¬ 
 blem is, where the canister and its sur¬ 
 rounding cases are painted or vitreous. 
 This condition will be found to , alter 
 materially the proportion of the result. 
 When two such surfaces with unequal 
 degrees of heat, are made to front each 
 other, they will not, like metallic plates,. 
 act the same as if they were quite insulat¬ 
 ed; but must, by their pulsatory energies, 
 exert a mutual influence to accelerate the 
 progress towards an equilibrium. If their 
 visual magnitude be very considerable, 
 or their extent great in comparison of 
 their distance, almost the whole of those 
 opposite dispersive pulsations, will be 
 intercepted and received on both sides. 
 But, with a moderate difference of tem¬ 
 perature, the vibratory discharge, consti¬ 
 tutes very nearly the half of the ordinary 
 measure of communication. Therefore, 
 
 ‘ Pages .S80, 381. 
 
118 EFFECTS OF HEAT. _ 
 
 the vitreous or painted surfaces must emit 
 
 or absorb heat, one-half faster than if tliey 
 were removed beyond each others sphere 
 of action, bnt accompanied by the same 
 intercluded atmosphere. ^ 
 
 “ If the one surface be completely en¬ 
 compassed by the otlier, it is evident, that 
 the exterior will receive all the diverging 
 pulsations; and, if the interior be not dis¬ 
 proportionately small, it must, in its turn, 
 intercept those which are reciprocally 
 convergent *. 
 
 95. “ 3d, The last branch into , which 
 the problem divides itself, is, that where 
 vitreous and metallic surfaces are pro¬ 
 miscuously^ combined. But as such pos¬ 
 sible combinations must, evidently, be 
 very numerous, I shall select only their 
 principal varieties. 
 
 “ Suppose a painted canister is included 
 within a bright tin case. If the reflective 
 
 Pages 385, 386. 
 
effects of heat. 
 
 119 
 
 power of the internal surface of the case 
 were absolutely complete, the progress of 
 refrigeration would be exactly the same 
 as if the canister had a metallic lustre; 
 for the discharge of heat by pulsa:tion 
 would then be rendered altogether abor¬ 
 tive, being constantly sent back from the 
 case to its source, and there re-absorbed. 
 The effect would thus be comparatively 
 much greater than in any of the preced¬ 
 ing instances. However, the defective 
 reflection, or partial absorption of the tin, 
 sensibly modifies the result. It is obvi¬ 
 ous, that the mean temperature of the 
 intercluded air, -will be determined in the 
 same manner as before. But, while a 
 polished metallic surface enxits nine parts 
 of heat, a painted one disperses sixteen. 
 Of the sixteen parts, therefore, which the 
 canister is capable of discharging, no 
 more than ten prove really effective, the 
 additional part only being absorbed by 
 the inner surface of the case. Hence, the 
 temperature of the exterior surface, must 
 be somewhat greater than the mean in¬ 
 ternal difference, to enable it to disperse 
 
120 EFFECTS OF HEAT. 
 
 its invigorated accesions of heat into free 
 
 space. 
 
 “ Let the position be now reversed, the 
 surface of the canister being clear, and its 
 exterior case painted on both sides. This 
 case will, therefore, absorb at its inner 
 surface, ten parts of heat, of which the 
 canister makes an effective discharge; but, 
 with the same difference of temperature, 
 it would disperse sixteen parts into the 
 free external atmosphere *. 
 
 “ It would be superfluous to prosecute 
 this subject any farther. The examples 
 which have been chosen are sufficient to 
 explain the varying mode of investigation, 
 When several cases are employed, alter¬ 
 nately vitreous and metallic, the effect is 
 nearly the same as if they were all metallic; 
 but the general influence, will depend 
 chiefly on the quality of the outmost sur¬ 
 face. For the same reason, the vitreous 
 or painted smTaces, will have much less 
 
EFFECTS OF HEAT. 
 
 121 
 
 power to retard the process of cooling 
 when they lie adjacent, than when they 
 are interspersed *. 
 
 “ With equal facility, may be deter¬ 
 mined the progress of refrigeration, which 
 obtains on the immersion of die apparatus 
 in a liquid mass. Since the discharge of 
 heat by external pulsation is now • pre¬ 
 cluded, the nature of the extreme bound¬ 
 ary, will have no influence whatever on 
 the measure of effect. This-result must 
 depend almost entirely on the quality, the 
 position, and the number of the interior 
 surfaces f. 
 
 “ A cylindrical canister of planished tin, 
 three inches in diameter and height, and 
 which in still air takes 117' to cool, from 
 20° to 10° would require 249' if in¬ 
 cluded regularly within a similar cylinder 
 of four inches, but only 185' if the whole 
 were immersed in a tub of water. The 
 same canister when painted, would, in a 
 
 t Page 3S6. 
 
122 
 
 EFFECTS OF HEAT. 
 
 close room, cool in 61', or, surrounded 
 with its case likewise painted, in 98', and 
 both plunged in water would take only 
 64'. 
 
 “ In all these examples, the canister and 
 its several cases are regularly separated 
 from each other by intervals of half an 
 inch. If the divisions approach nearer, 
 their effect soon becomes altered; for the 
 successive strata of intercluded air as they 
 diminish in thickness, lose in some degree 
 their internal mobility, and begin passively 
 to transmit heat like a solid mass. When 
 the terminating surfaces mutually approx¬ 
 imate, not only is the fluidity of the thin 
 shells of air proportionally cramped, but 
 the power of commimication is likewise 
 invigorated by the sliortness of the pas¬ 
 sage, and consequently the quicker grada¬ 
 tion of temperature. On both these 
 accounts, therefore, the quantity of trans¬ 
 mission will increase with most rapid 
 progress, as the septa contract their limits. 
 Thus, a cylindrical tin canister of three 
 inches in diameter and height, placed 
 
EFFECTS OF HEAT. 
 
 123 
 
 within a similar one of four inches, will 
 cool about one-sixtieth part faster, if 
 shifted from its position in the middle to 
 a quarter of an inch from the bottom; 
 and nearly one-nintieth part still faster, 
 when advanced only an eight of an inch 
 from that boundary. Hence, we may 
 compute that a stratum of air one quarter 
 of an inch thick, transmits through its 
 substance, about a sixth part of the heat 
 which it is fitted to communicate in the 
 ordinary mode, and if reduced to half this 
 thickness, it will deliver nearly equal 
 shares in both ways. 
 
 “ But to discover more' accurately the 
 progress of this internal transmission, I 
 procured another intermediate cylinder of 
 tin, with a moveable lid and three inches 
 and three quarters in diameter. The 
 three inch canister enclosed within this, 
 had its rate of cooling reduced to 7-15ths. 
 But calculation gives the difference 
 being only and, consequently, the 
 
 aberration or accelerating influence, cor¬ 
 responding to an interval of three-eights 
 
124 EFFECTS OF HEAT. 
 
 of an inch, must be extremely small. 
 The diameters of the cylinders are as 4 
 and 5, and their surfaces as 16 and 25. 
 Therefore, the temperature of the internal 
 canister being denoted by unit, that of the 
 outer case is tV x The mutual 
 
 difierence is Itt, and hence, the canister 
 exceeds the temperature of the interjacent 
 
 ^7 25 + 16 ''375= 37^' fraction 
 
 will express the ordinary measure of com¬ 
 munication; but the actual discharge of 
 heat is 7-15ths, or -Hf, and, therefore, 
 or about the twelftli part of the whole, is 
 conveyed away through tlie stratum of air 
 by passive transmission. 
 
 “ When the intermediate cylinder was 
 included within the four inch one, their 
 interval being only the eight part of an 
 inch, the deviation appeared now to have 
 most rapidly increased. The rate of cool¬ 
 ing, instead of 17-47ths was only reduced to 
 17-26ths. The opposite surfaces being as 
 225 to 256, or very nearly as 15 to 17, 
 the temperature of the exterior one is x 
 
EFFECTS OF HEAT. 
 
 125 
 
 ■ 4 = 14 , and, consequently, the internal can¬ 
 ister must exceed the temperature of the 
 thin stratum of intercluded air by 4| x 44 = 
 •144. This must denote the ordinary 
 discharge of heat, but the real consump¬ 
 tion is 44=144, which is nearly triple the 
 former. Therefore, when the shell of air 
 is only the eight of an inch in thickness, 
 of 31 parts of heat, 10 are carried off by 
 the general process, and 21 by quiescent 
 communication. 
 
 “ But the close proximity, and still 
 more the partial contact of the canister 
 with its exterior case, has not merely a 
 negative influence to diminish the retard¬ 
 ation of cooling. It must actually accel¬ 
 erate the dispersion of heat, since, in 
 effect, it occasions an artificial enlarge¬ 
 ment of surface. A tin canister of two 
 inches square, will cool one-half slower, 
 when planted in the centre of a similar 
 one of four inches. But if it be made to 
 touch three sides of the case, it will cool 
 about three times faster than at first; for 
 these, sides having the same temperature as 
 
126 
 
 EFFECTS OF HEAT. 
 
 the canister, and presenting twice its extent 
 of surface, must double the refrigerating 
 action, exclusive of the co-operation of 
 the remaining sides, which will add at 
 least one-half more. 
 
 “To produce their proper effect, there¬ 
 fore, it is requisite that the cases should 
 be perfectly detached or insulated. The 
 retardation of the process of cooling, de¬ 
 pends entirely on the coldness of the 
 external surface. But metals conduct 
 heat so freely, that even a partial contact 
 might be sufficient to cause an almost 
 equal diffusion. If a round tin vessel of 
 a broad and rather flat shape, have a cap 
 fitted at each end, capable of being drawn 
 out to different small distances, the rate 
 of cooling will continue very nearly die 
 same, through all the gradations from the 
 position of absolute contiguity, till the 
 circular plates are separated by an interval 
 of perhaps three quarters of an inch. 
 The narrow rims embracing the canister, 
 rapidly abstract heat, and convey it to the 
 prolonged boundaries. We, hence, see 
 
EFFECTS OF HEAT. 
 
 127 
 
 the defect of the ordinary form of pots 
 with double lids, designed for culinary 
 purposes 
 
 96. Many useful practical applications 
 of the principles here investigated might 
 be made, Mr. Leslie has proposed a 
 method of preserving ice, by enclosing it 
 within a number of tin canisters, and has 
 applied it for preserving liquids in a cool 
 state in warm climates; on the same prin- 
 
128 
 
 EFFECTS OF HEAT. 
 
 ciple,- a good mode of protecting water- 
 pipes from freezing, would be to enclose 
 them in tin-plate tubes, leaving a space 
 of about an inch all round the leaden 
 pipes. It is also well worthy of consid¬ 
 eration, how far these principles might be 
 applied in the construction of the casing, 
 for the preservation of the heat of cylin¬ 
 ders of steam engines. Its advantages in 
 many situations of steam rubes is quite 
 obvious. 
 
 “ Refrigeration of Bodies in various Unds of 
 Elastic Fluids. 
 
 97. “ Bodies cool in very different times 
 in some of the elastic fluids. Mr. Leslie 
 was the first, I believe, who noticed this 
 fact; and he has given us the results of 
 his experiments on common air and hy- 
 drogeneous gas, of the common density, 
 and also rarefied in various degrees. 1 
 made some experiments with a view to 
 determine the relative cooling powers of 
 the gases, .the result of which, it may be 
 proper to give. 
 
EFFECTS OF HEAT. 
 
 129 
 
 Thermometer immersed in \ cooled in 
 carbonic acid gas - - | 112 seconds. 
 —sulphuretted hydrogen, 
 nitrous oxide, and ole¬ 
 fiant gas - - - - 
 
 —com. air, azotic and ox- 7 jqq 
 ygengas - - - - j 
 
 —nitrous gas - - - - 90 
 
 —carburet, hydrogen or 7 
 coal gas - - - - j 
 
 —^hydrogen.40 
 
 “ Condensed air cools bodies more 
 rapidly than air of common density; and 
 rarefied air less rapidly, whatever be the 
 kind.—^The results of my own experience 
 for common air were as follows: 
 
 Thru, cool, In 
 
 - - - 85 seconds. 
 
 - - 100 
 
 - - - 116 
 
 - - 128 
 
 - - - 140 
 
 - - 160 
 
 - - - 170 
 R 
 
 I 100 + 
 
130 
 
 EFFECTS OF HEAT. 
 
 “ The expenditure of heat by radiation, 
 being the same in hydrogenous gas as in 
 atmospheric air, we may infer, it is the 
 same in every other species of gas; and, 
 therefore, is performed independently of 
 the gas, and is carried on the same in 
 vacuo as in air. Indeed, Mr. Leslie him¬ 
 self admits, that the diminution of the 
 effect consequent upon rarefaction is ex¬ 
 tremely small, which can scarcely be con¬ 
 ceived if air were the medium of radia¬ 
 tion. 
 
 “ The effect of radiation being allowed 
 constant, that of the density of the air 
 may be investigated, and will be found, 
 I believe, to vary nearly or accurately as 
 the cube root of the density *. 
 
EFFECTS OF HEAXr 
 
 131 
 
 SECTION VI.. 
 
 Boiling Or Ebullition. 
 
 98. The internal comniotion excited in 
 any liquid, by the successive conversion 
 of the lower portions of the fluid into 
 vapour, and their violent effort under this 
 expansive and elastic form, is denominated 
 boiling or ebullition. Though usually it 
 is not necessarily produced by the applica¬ 
 tion of heat; for the removal of pressure 
 from the surface of the fluid, will produce 
 boiling in a liquid, previously in a quies¬ 
 cent state. Thus, if a vessel holding 
 warm water, be placed under the receiver 
 of an air pump, as the exhaustion pro¬ 
 ceeds and gradually withdraws the pres¬ 
 sure, at a certain point of rarefaction 
 boiling takes place. This point, therefore, 
 is not so unchangeable as the melting 
 point, for so far as is yet known, the 
 melting point of each kind of matter is 
 always the same. 
 
132 • EFFECTS OF HEAT. 
 
 99. “ Every particular liquid has a fixed 
 point, at which this boiling commences, 
 (other things being the same,) and this is 
 called the boiling point of the liquid. 
 Thus, water begins to boil when heated 
 to 212°. It is remarkable, that after a 
 liquid has begun to boil, it never becomes 
 any hotter, however strong the fire be to 
 which it is exposed. A strong heat, in¬ 
 deed, makes it boil more rapidly, but does 
 not increase its temperature. This was 
 first observed by Dr. Hooke. 
 
 “ The following Table contains the 
 boUing point of a number of liquids. 
 
 Bodies, Boiling PoinU 
 
 “ Ether - - - - 98 
 
 Ammonia - - - 140 
 Alcohol .... 176 
 
 Water.212 
 
 Muriat of Ume . . 230 
 Nitric acid .... 248 
 
 Bc'dlu. Bolling PoU 
 
 Sulphuric acid . . S90 
 Phosphorus ... Soi 
 Oil of turpentine . 560 
 Sulphur ..... 570 
 Lintseed oil . . . 600 
 Mercury . . . .660 
 
 “ From the experiments of Professor 
 Robison, it appears, that in a vacuum all 
 liquids boil about 145° lower than in the 
 open air, under a pressure of 30 inches of 
 mercury; therefore, water would boil in 
 
EFFECTS OF HEAT. 
 
 133 
 
 vacuo at 67°, and alcohol at 34°. In a 
 Papin’s digester, the temperature of water 
 may be raised to 300°, or even 400°, 
 without ebullition. But the instant that 
 this great pressure is removed, the boiling 
 commences with prodigious violence 
 
 100. “ The opposite influence of heat 
 and pressure on the constitution of fluids, 
 is well exhibited by a very simple, yet 
 striking experiment. Take a large thin 
 phial, and having warmed it gradually to 
 avoid the risk of cracking the glass, fill it 
 completely with boiling water, cork it 
 tight and expose it to a current of cold 
 air. As the water cools, it necessarily 
 contracts its volume, and leaving an 
 Imperfect vacuity below the neck of the 
 phial, it hence becomes, to a considerable 
 degree, relieved from the load of atmo¬ 
 spheric pressure; it, therefore, soon begins 
 again to boil, nay, it will boil more brisk¬ 
 ly the faster it cools; and this singular 
 appearance, so contrary to our usual no- 
 
134 
 
 EFFECTS OF HEAT. 
 
 rions, may continue, perhaps, for the 
 space of half an hour, till the water has 
 grown as cold almost as the temperature 
 of the human body 
 
 101. From this cause of difference of 
 pressure, the boiling point differs with 
 the state of the atmosphere in the same 
 country, and is very different in different 
 countries. Thus, for instance, the boiling 
 point in Britain, under the mean pressure 
 of the atmosphere, is at 212° of Fahren¬ 
 heit, while at Munich in Bavaria, it is 
 only 209i°, and at Quito in South Amer¬ 
 ica, much lower, owing to its great height 
 above the level of the sea, where the pres¬ 
 sure of the atmosphere is greatly reduced. 
 Hence, the boiling point has been em¬ 
 ployed to indicate the heights of places 
 above the level of the sea. 
 
 102. “ The circumstances which precede 
 or accompany the phenomenon of boiling, 
 are best observed in a thin transparent 
 
 J.ee*s Cyclopedia, Art. Boiling. 
 
EFFECTS OF HEAT. 
 
 135 
 
 flask, nearly filled with water, and sus¬ 
 pended over a lamp or a charcoal fire. 
 Numerous minute globules are seen col¬ 
 lecting from all points towards the sides, 
 and rising in a stream to the surface; 
 occasioned evidently by the discharge of 
 air, which is always in some proportion 
 combined with water. As the heat in¬ 
 creases, the liquid particles near the bot¬ 
 tom of the flask, suddenly burst into 
 steam, and shoot upwards; but in ascend¬ 
 ing through the colder mass, they again 
 collapse, stop their progress and seem lost. 
 Such alternate expansions and contrac¬ 
 tions, by throwing the fluid into a gentle 
 tremour, frequently causes a peculiar sort 
 of singing noise, which is rightly sup¬ 
 posed to betoken the approach of actual 
 boiling. This singing is more likely to 
 happen in the case where heat is applied 
 partially; for instance, if a tea-kettle be 
 placed at the side of the fire, since the 
 heat is then more slowly and unequally 
 diffiised through the body of the water. 
 But after the whole contents being fully 
 penetrated, are warmed up to the requisite 
 
136 
 
 EFFECTS OF HEAT. 
 
 degree of intensity, the steam, as fast as 
 it is formed, ascends continually, and 
 escapes unimpaired through the fluid, 
 which it, therefore, heaves with violent 
 agitation 
 
 103. When heat is applied to the bot¬ 
 tom of a vessel containing water, the 
 heated particles nearest the bottom be¬ 
 comes specifically lighter, and, therefore, 
 mount upward and quickly dispose them¬ 
 selves in horizontal strata, according to 
 their respective degrees of temperature. 
 Thus, a vessel full of water is quickly- 
 heated from below. But to commimicate 
 heat downwards from this hydrostatic 
 law, is tedious and ineffectual. Not like 
 a bar of iron, which is heated almost 
 equally soon, whether its upper or lower 
 end be thrust into the fire. So difficult is 
 it to heat fluids from above, that Count 
 Rumford inferred, that they v^ere absolute 
 non-conductors of heat. A mass of water 
 heated from below, has the temperatures 
 
 * Ree’s Cyclopedia, Art. Boilinj. 
 
EFFECTS OF HEAT. 
 
 137 
 
 of the successive strata, reckoning upwards 
 in an accelerating progression, and the 
 centre of the vessel partakes more of the 
 temperature of the bottom, than of the top. 
 The progression is very nearly arithmetical, 
 and Mr. Leslie informs me, that he found 
 it about one degree, for every 10 inches in 
 depth. Thus, when at 212° at the surface, 
 it will be 213°; at 10 inches below, 114°; 
 at 20 inches, &c. 
 
 104. “ If a vessel containing water be 
 placed over a steady fire, the water will 
 grow continually hotter, till it reaches the 
 limit of boiling, after which the regular 
 accessions of heat, are wholly spent in 
 converting it into steam. The water, 
 therefore, remains at the same pitch of 
 temperature, however fiercely it boils. 
 The only difference is, that with a strong 
 fire it sooner comes to boil, and more 
 quickly boils away. Hence the reason 
 why a vessel full of water, and plunged 
 into the centre of a larger one, which is 
 likewise filled with that fluid, barely 
 acquires the boiling heat, but will never 
 actually boil. 
 
 S 
 
138 
 
 EFFECTS OF HEAT. 
 
 105. “ Hence the boiling heat of a deep 
 cauldron, is always rather greater than that 
 of a shallow pan. This excess, we might 
 estimate at nearly one degree of Fahrenheit, 
 for each foot of depth. The heat of ebul¬ 
 lition must also rise somewhat higher, if 
 the steam be not allowed to escape as fast 
 as it is generated; for which reason, there 
 may be a slight difference of energy between 
 rapid and slow boiling. 
 
 106. “ But the position of the boiling 
 point, is likewise modified by the influence 
 of chemical attraction. Thus, sugar, com¬ 
 mon salt, and otlier saline substances, have 
 all of them a tendency to fix water, and 
 retard the crisis of its conversion into 
 elastic vapour. Strong brine will not boil 
 until it is heated up several degrees above 
 the ordinary limit. Hence, a vessel con¬ 
 taining fresh water, and immersed in 
 another which is filled with brine, will 
 gently boil while the surrounding fluid 
 only simmers. On the other hand, the 
 addition of alcohol, renders water more 
 volatile. In the distilation of spirits, the 
 
EFFECTS OF HEAT. 139 
 
 fermented liquor in the copper, boils 
 always at a lower temperature, or at some 
 intermediate point between the ebullition 
 of water, and that of alcohol. The spirit¬ 
 uous fumes which rise, carry along with 
 them a portion of evapourated water 
 
 Of Steam or Vapour. 
 
 107. Elastic fluids, which by cold or 
 pressure are reduced wholly to a liquid 
 state, are denominated vapour or steam. 
 Such are the elastic fluids arising from 
 water, alcohol, ether, mercury, &c. It is 
 proper to distinguish these elastic fluids 
 from those which have not yet been re¬ 
 duced into a liquid state, by the agency 
 of cold and pressure, which are commonly 
 denominated gases. 
 
 108. It is stated in Article 44, that bodies 
 by changing their state, also change their 
 specific heat; and hence, when a fluid is 
 converted into vapour, it absorbs a great 
 quantity of heat. Were a great quantity 
 
 e’s Cyclopedia, vol. iv. part 2. 
 
140 EFFECTS OF HEAT. 
 
 of heat not necessary to the production of 
 vapour, and the body already heated to 
 that temperature, wliich it cannot pass the 
 smallest possible degree, without being 
 converted into steam; the consequence 
 would be, an explosion of the whole water 
 like gun-powder. But this great quantity 
 of heat enters gradiially into the vapour 
 while it is forming, witliout making it 
 perceptibly hotter to the thermometer, for 
 it is found to be exactly of the same tem¬ 
 perature, as the boiling water from which 
 it arose. The water must be raised to a 
 certain temperature, because of that tem¬ 
 perature only, it is disposed to absorb 
 heat, and it is not instantly exploded, 
 because in that instant, there cannot be 
 had through the whole mass, a sufficient 
 supply of heat. 
 
 On the other hand, it is found, that 
 when the vapour of water is condensed 
 into a liquid, the same great quantity of 
 heat is evolved, and the water into which 
 it is changed, does not become colder to 
 the thermometer by the loss of this great 
 
EFFECTS OF HEAT. 
 
 141 
 
 ipantity of heat. We are indebted to 
 Dr. Black for this great discovery, which 
 was the origin of his doctrine of latent 
 heat. He brought to maturity his specu¬ 
 lations on this subject, between the years 
 1759 and 1763*. In these inquiries, he 
 was assisted by his pupils, Mr. Watt and 
 Dr. Irvine. Soon after this period, {viz. 
 in 1764,) Mr. Watt made his first great 
 improvement on the steam-engine. 
 
 109. The combination of a certain 
 quantity of heat in steam. Dr. Black estab¬ 
 lished by the following facts. 
 
 The water in a vessel set upon the fire, 
 becomes hotter till it reaches 212°, but 
 afterwards, although heat must bei con¬ 
 stantly proceeding from the fire, no increase 
 of temperature takes place, the heat must 
 therefore combine with that part of the 
 water which flies off in steam. But the 
 temperature of the steam, is only 212°, 
 therefore the heat combined with it, does 
 not increase the temperature. 
 
142 
 
 EFFECTS OF HEAT- 
 
 110. “ Mr, Watt put three inches of 
 water into a small copper digester, and 
 screwing on- the lid, he left tire safety- 
 valve open. He then set it on a clear fire 
 of coaks, and after it began to boil and 
 produce steam, he allowed it to remain on 
 the fire half an hour, with the valve open. 
 Then taking it off the fire, he found that 
 an inch of water had boiled away. In 
 the next place, he restored that inch of 
 water, screwed on the lid, and set it on the 
 fire; and as soon as it began to boil, he 
 shut the safety valve, and allowed it to 
 remain on the fire half an hour as before. 
 The temperature of the whole, was many 
 degrees above the boiling point. He took 
 it off the fire and set it upon ashes, and 
 opened the valve a very small matter. 
 The steam rushed out with great violence, 
 making a shrieking noise for about two 
 minutes. When this had ceased, he shut 
 the valve, and allowed all to cool. When 
 he opened it, he found that an inch of 
 vv'ater -was consumed 
 
EFFECTS OF HEAT. 
 
 143 
 
 111, Dr. Black found, in this climate, 
 that it requires 6 times the number of 
 minutes to boil off a small quantity of 
 water, than it takes to bring it to boil. 
 
 Hence, 6 times the quantity of heat, 
 which it requires to bring the water to 
 the boiling point, is combined with the 
 steam, and Mr. Watt found from accurate 
 experiments, an exact coincidence between 
 the heat thus combined with the vapour, 
 and that which emerges from it when 
 condensed or re-converted into water. 
 “ And that the heat obtainable from steam, 
 capable of sustaining the ordinary pressure 
 of the atmosphere^ is not less than 900° of 
 Fahrenheit's scale^ and that it does not exceed 
 950°*.” Calculations from experiments 
 made by Lavoisier, on the melting of ice, 
 produce a value somewhat higher, of the 
 heat which Dr. Black called latent of 
 steam, “ f making it 1000°, or perhaps a little 
 
 more. 
 
144 EFFECTS OF HEAT. 
 
 Hence, the great scalding power of 
 steam. Hence also, the great heat pro¬ 
 duced in the refrigltory of a common still. 
 
 112. Dr. Black observes, “ that it is this 
 great quantity of heat contained in steam, 
 that makes it so powerful and effectual in 
 the business of cookery He farther 
 says, “ steam is the most effectual carrier 
 of heat that can be conceived, and will 
 deposite it only on such bodies as are 
 colder than boiling water f.” 
 
 113. Whenever a body hotter than 212° 
 comes in contact with boiling water, it 
 raises its temperature and causes it to 
 expand, but when a body colder than 
 212° touches it, the heat quits the vapour, 
 and it becomes water, or is condensed. 
 
 114. Two English gallons of ice-cold 
 water, dashed in small drops through the 
 capacity of a steam cylinder containing 
 three hogsheads, condenses the vapour 
 which fills it :j:.” 
 
 t Ibid. 181. 
 
 t Ibid. 177. 
 
EFFECTS OF HEAT. 
 
 145 
 
 115. Vapour may be condensed by 
 mechanical compression, as well as by 
 cold. 
 
 116. “ Mr. Watt has made a great 
 number of experiments, for ascertaining 
 the bulk into which a cubic inch of water 
 is expanded, when it composes the steam, 
 which at the temperature 212°, sustains 
 the pressure of the atmosphere; some of 
 these were direct, by evaporating a kaown 
 quantity of water, others were more cir¬ 
 cuitous, deduced from the performance 
 of his engines. The medium result, gave 
 about 1800 cubic inches. We may say 
 that a cubic inch of water, forms a cubic 
 foot of such steam 
 
 117. “ As much heat is contained in one 
 gallon of water in the form of steam, as 
 would bring 54 gallons of ice-cold water, 
 to a boiling heat f.” 
 
 118. From the low temperature at which 
 water boils in vacuo, it occurred to Mr. 
 
 » Blade’s Teitures, vol. i. p. 176. , f Black’s Lectures, vol. i. p. 185. 
 
 v;, T 
 
146' EFFECTS OF HEAT. 
 
 Watt, Dr. Black and others, that distilling 
 in vacuo, would be productive of a very- 
 great saving of fuel. With this view, Mr. 
 Watt instituted a set of experiments, but 
 says Dr. Black, “ The unexpected result of 
 these experiments is, that there is no 
 advantage to be expected in the manufac¬ 
 ture of ardent spirits, by distilling in vacuo. 
 For. we find that the latent heat cf the 
 
 Steam, is at least as much increased, as the 
 
 sensible heat is diminished 
 
 119. In the course of a set of experi¬ 
 ments, made for a practical purpose on 
 steam, of very different degrees of density, 
 a curious fact, I am informed, was observed, 
 viz. that the same quantity of water passed 
 through the same aperture in the form of 
 steam, during the same space of time, what¬ 
 ever was the degree of density. 
 
 120. “ The elasticity of all the elastic 
 fluids, into which liquids are converted by 
 heat, increases -with the temperature; and 
 the vapour formed when the liquid boils' 
 
 ' Black’s Lectures, toI. i. p. 190. 
 
EFrECTS OF HEAT. 
 
 147 
 
 ia the open air, possesses an elasticity just 
 equal to that of air, or capable at a medium 
 of balancing a column of mercury, 30 inches 
 high * ” 
 
 121 “ TABLE of the force of Steam, at diff¬ 
 erent Temperatures from actual experiment 
 (Betamourt, in Prony’s Architecture, Hydrau- 
 
 lique.J 
 
 Force in inches 
 
 Temperature. 
 
 of mercury. 
 
 32° - 
 
 0 
 
 42 - 
 
 - ,08 
 
 52 - 
 
 - .21 
 
 62 - 
 
 - .38 
 
 72 ■ - 
 
 - .58 
 
 82 - 
 
 - .87 
 
 92 - 
 
 - 1.26 
 
 102 - 
 
 - 1.74 
 
 112 - 
 
 - 2.37 
 
 122 - 
 
 - 3.16 
 
 132 - 
 
 - 4.16 
 
 142 - 
 
 - 5.43 
 
 152 - 
 
 - 7.00 
 
 Temperaturei 
 
 Force in inch 
 of mercury. 
 
 162° - 
 
 - 9.07 
 
 172 - 
 
 - 11.0 
 
 182 - 
 
 - 14.9 
 
 192 - 
 
 - 18.7 
 
 102 - 
 
 - 23.7 
 
 212 - 
 
 - 29.8 
 
 222 - 
 
 - 37.4 
 
 232 - 
 
 - 46,5 
 
 242 - 
 
 - 57.3 
 
 252 - 
 
 - 69.7 
 
 262 - 
 
 - 83.6 
 
 272 - 
 
 - 97.1 
 
 282 - 
 
 - 10.8 
 
 “ In the 5th volume of ‘ Memoirs of the 
 Manchester Society,’ a table of the force of 
 vapour, for each degree of Fahrenheit, is 
 given by Mr. Dalton; the numbers below 
 
148 
 
 EFFECTS OF HEAT. 
 
 212 degrees, from experiment, and the 
 higher numbers from calculation, Mr. 
 Betancourt, however professes to have 
 obtained all the above results front! actual 
 experiment,” 
 
 122. “ TABLE of the Expansion of a given Bulk 
 
EFFECTS OF HEAT. 149 
 
 123 . “ TABLE of the Expansion of Liquids 
 by Heat” 
 
 124 . “ TABLE of the Expansim of Water 
 by Heat” 
 
 100000 
 
 100030 
 
 100106 
 
 100182 
 
 100273 
 
 100471 
 
 100624 
 
 100777 
 
 101006 
 
 101220 
 
 101495 
 
 101755 
 
 102040 
 
150 
 
 EFFECTS OF HEAT. 
 
 SECTION VII. 
 
 Of Ignition- 
 
 125. “ By ignition (says Mr. Murray) is 
 meant that illumination or emission of light- 
 produced in bodies, by exposing idiem to a 
 high temperature, and -which is not accom¬ 
 panied by any other chemical change in 
 them. It is to be distinguished from 
 combustion, a process in which there is 
 also the emission of light and heat. Com¬ 
 bustion is always the result, not of mere 
 increase of temperature in the body which 
 suffers it, but of the chemical action of the 
 air, or of a principle wliich the air contains. 
 A certain class of substances, therefore, de¬ 
 nominated Combustible, are alone suscepti¬ 
 ble of it, and when the process has ceased, 
 the body remains no longer combustible. 
 Ignition is an effect of the operation of calo¬ 
 ric alone; it is wholly independent of the 
 air, for by immersing completely any body 
 in melted glass, it is rendered luminous; 
 all bodies, at least all solid and liquid 
 substances, are equally susceptible of it; 
 
jEFFECTS of heat. 
 
 151 
 
 and if it has ceased from a reduction of 
 temperature, it may be renewed by the 
 temperature being again raised.” 
 
 126. “ The point of temperature, at 
 which the first stage of ignition takes 
 place, or at which, in common language, 
 bodies arrive at a red heat, appears to be 
 the same in all. Mr. Wedgwood gilded 
 lines, running across a piece of earthen 
 ware, and luted it to the end of a tube, 
 which was placed in a heated crucible; 
 the eye being applied to the other extrem¬ 
 ity of the tube, no difference of time could 
 be perceived in either the gold or the 
 earthen ware, beginning to shine. No 
 two substances can be more dissimilar; 
 and it may be inferred that all bodies 
 become red-hot at the same temperature. 
 As this can be judged of, only by the 
 illumination, it must, of course, appear 
 various according to circumstances. In a 
 body, therefore, which in the dark appears 
 at a low red heat, the illumination will 
 not be visible in day-light. Sir Isaac New¬ 
 ton, by observing the celerity with which 
 
152 
 
 EFFECTS OF HEAT. 
 
 a body cools, and calculating on tlie pi’in- 
 ciple which has been already pointed out, 
 (p. 161), concluded, tliat ignition visible 
 in the dark, corresponds with 635° of 
 Fahrenheit’s scale, full red heat with 752°; 
 and ignition visible in day-light, with 
 above 1000°. Dr. Irvine having found 
 that quicksilver boils at 672°, and having 
 observed, that boiling mercury did not 
 appear at all luminous in the dark, it ne¬ 
 cessarily followed, that the point of igni¬ 
 tion must be higher than Newton had 
 supposed it to be. He had farther found, 
 that when equal bulks of iron and water 
 at different temperatures are mixed to¬ 
 gether, the resulting temperature is nearly 
 the mean, and he applied this method to 
 determine the point of ignition; the result 
 is not precisely known; but the heat of a 
 common coal fire, he found to be 790° or 
 796°*. Mr. Wedgwood by the expan¬ 
 sion of the piece of silver, measured by a 
 gage of baked clay, by which he endeav¬ 
 oured to cormect his thermometer with 
 
EFFECTS OF HEAT. 
 
 15S 
 
 Fahrenheit’s, as has been already ex¬ 
 plained, fixed the point of ignition visible 
 in the dark, at —1 of his scale, which cor¬ 
 responds with 947° of Fahrenheit; and 
 ignition in day-light, he placed at the 
 commencement of his scale, or 1077°. 
 This dllFers from the preceding results; 
 and as it is probable that the silver would 
 suffer an increasing expansion, this might 
 cause the temperature to appear higher 
 than it actually was, and hence, have 
 given the point of ignition too high. It 
 is probably not far from 800° of Fahren¬ 
 heit. 
 
 127. “ By raising the temperature, the 
 illumination becomes brighter, and the 
 red heat acquires a mixture of yellow” 
 rays. At length, by increasing the heat, 
 we have the due proportion of coloured 
 rays, which forms perfectly white light. 
 This is the highest state of ignition, or 
 any farther rise of temperature produces 
 no apparent change. 
 
 U 
 
154 
 
 EFFECTS OF HEAT. 
 
 128. “ Ignition continues undimin- 
 islied, as long as the temperature is kept 
 up, unless the heat be such as to volatilise 
 or alter the constitution of the ignited 
 body. 
 
 129. “ The aeriform fluids are not 
 brought into a state of illumination by 
 heat. This was observed by Dr. Fordyce, 
 in the example of the vapour, at the end 
 of the flame of a blow-pipe, which though 
 itself not visibly luminous at its extrem¬ 
 ity, will, if applied to glass, raise it to a 
 white heat*. The fact was afterwards 
 also established by Mr. Wedgwood. Air 
 was forced to pass through an earthen 
 tube, in a state of ignition, and was con¬ 
 ducted into a globular vessel, from which, 
 
 ‘ by an opening in the top, it was allowed 
 to escape; while by another opening in the 
 side, closed by a piece of glass, the eye 
 could be directed into the inside of the 
 globe. On looking into it, the air which 
 had passed through the ignited tube was 
 
 ' PhU. Trans, vol. Ixvi. p. 
 
EFFECTS OF HEAT. 
 
 155 
 
 not luminous; but if a solid body, as a 
 piece of gold, Was suspended in it, this 
 became luminous *, This is probably 
 owing to the tenuity of aeriform fluids, 
 whence they present too few points in a 
 given space, to project a quantity of light 
 sufficient to excite vision. 
 
 130. “ The phenomena of ignition are 
 produced, not only by the application of 
 heat, but likewise by friction and attri¬ 
 tion. When a piece of steel is struck 
 against a flint, small particles of the 
 metal are detached, which are at a red 
 heat. Or if various hard minerals be 
 made to act strongly against each other, 
 they give out light. By applying, for 
 exahaple, quartz or agate to the circum¬ 
 ference of a wheel of fine grit, revolving 
 at a moderate rate; Mr. Wedgwood ob¬ 
 served, that the substance applied became 
 brightly red even in day-light, at the 
 touching part; if the wheel revolved at a 
 quicker rate, the part in contact emitted a 
 
 • Phil. Trans, vol. Ixvl. p. 
 
156 EFFECTS OF HEAT, 
 
 pure white light; and in both cases, glow¬ 
 ing sparks were continually emitted, some 
 of which were not extinguished before 
 they had passed twelve or fourteen inches 
 through the air. They exploded gun¬ 
 powder and inflammable air; and burnt 
 the skin, a sufficient proof that they were 
 not merely luminous or phosphorescent, 
 but ignited, or at a red heat. In the same 
 mode, glass and porcelain were raised to a 
 red heat. These appearances from attri¬ 
 tion, are probably to be ascribed to the 
 heat which is excited, rising sufficiently 
 high to extricate their light, as the same 
 bodies become luminous when directly 
 heated, and as the same appearances are 
 not produced in substances which are 
 soft, these not having their temperature 
 raised by attrition 
 
 • Murray’s Chemistry, vol. i. p. 253—257. PhiL Tmns. for 
 1792, p. S9. 
 
Description of Plate 1 . 
 
 131. Fig. 1, is a comparative view of Fahrenheit’s scale, 
 and Mr. Dalton’s new divisions of the scale of the mercurial 
 thermometer. The interval from freezing to boiling water, 
 is 180° on both scales, and the extremes are numbered 32° 
 and 212° respectively. “ There are no other points of tem¬ 
 perature in which the two scales can agree 
 
 Fig. 2, represents Reaumeur’s scale, as also that of the 
 centigrade, (Art. 10, 11). 
 
 Fig. 3, shows the scale proposed by Mr. Murray, 
 (Art. 12). 
 
 Fig. 4, represents the connection of the mercurial ther¬ 
 mometer, with that of Mr. Wedgwood, (Art. 26). 
 
 Fig. 5, “ is the logarithmic curve, the ordinates of which, 
 are erected at equal intervals, and diminish progressively by 
 the ratio The intervals of the absciss or base of the 
 curve, represent equal intervals of temperature, (25° for 
 steam or aqueous vapour, and 34° for ethereal vapour,) the 
 ordinates represent inches of mercury, the weight of which 
 is equal to the force of steam at the temperature. Thus the 
 force of steam at 212°, and of ethereal vapour at 110°, new 
 scale, is equal to 30 inches of mercury; at 187° the force of 
 steam is half as much, or IS inches, and at 76°, that of 
 ethereal vapour is also 15 inches, &c. f ” (Art. 24.) 
 
 Fig. 6, represents Mr. Leslie^s differential thermo.metcr, 
 (Art. 80). 
 
 •Dalton’s Chem. Phil. p. 217. tDolton’sChem. Phil. p. 21S. 
 
 F.VD OF PARF FIRST. 
 
^econij* 
 
 HEATING 
 
 MILLS, DWELLING HOUSES, AND 
 PUBLIC BUILDINGS, 
 
 By STEAM. 
 
 SECTION I, 
 
 132. It may be proper, in general, to 
 mention, that the steam is usually gener¬ 
 ated in a boiler similar to those employed 
 for steam-engines, and having similar 
 apparatus for supplying it with water. 
 The boiler is placed in any convenient 
 
160 
 
 EFFECTS OF HEAT. 
 
 situation, in or near the building to be 
 warmed; from it the steam is conveyed in 
 pipes, through the various rooms where 
 heat is required. 
 
 Of the proportionate size of Boilers. 
 
 133. The proportionate size of boilers 
 is a point of considerable practical impor¬ 
 tance. It has been ascertained, that one 
 cubic foot of boiler will heat about two 
 thousand cubic feet of space, in a cotton 
 mill*; (See Notes A. and B.) and if we 
 reckon twenty-five f cubic feet for every 
 horse’s power X in a steam-engine boiler; of 
 course, such a boiler of a steam-engine, 
 would be capable of warming fifty thou¬ 
 sand cubic feet of space for every horse’s 
 power of the engine. 
 
 • In cotton mills the temperature is in general from TO to 80 degrees 
 of Fahrenheit. 
 
 f 1 am aware that the quantity of steam, which a boiler will pro- 
 Guce, depends much more on the surface applied to the fire, than on its 
 cubical contents: but I here allude to boilers of the form at present 
 most geneniUy used in steam-engines. Twenty-fiw cubic feet, how- 
 CTer, is an ample allo^s'ance. See Art. 64. 
 
 $ Respecting the resistance to -u'Wch a horse’s power is estimated by 
 mechanics, as being equal. See my “ Essay on the Teeth of Wheels.’* 
 
EFFECTS OF HEAT. 
 
 161 
 
 134. A separate boiler ought, however, 
 to be considerably larger than the extra 
 size allowed on a boiler, used for the joint 
 purpose of a steam-engine and warming a 
 mill; to avoid the inequality of heat inci¬ 
 dent to a boiler working to the full extent 
 of its capacity. 
 
 135. Having ascertained the size of the 
 boiler, the fuel may be easily estimated by 
 the following rule, which I believe Messrs. 
 Boulton and Watt adopt with respect to 
 their steam-engines: That is, about 14 lbs. 
 per hour of good Newcastle coal, for each horse s 
 power. It may be proper, however, in 
 general, to make a large additional allow¬ 
 ance for defects in furnaces, and inattention 
 in the attendants. See Art. 59—-70. 
 
 X 
 
162 EFFECTS OF HEAT. 
 
 SECTION II. 
 
 Of the proportion of Steam-pipe required to 'warm 
 a given i^pace. 
 
 136. In cotton mills, it has been ascer¬ 
 tained, that, in most cases, one superjicial 
 foot of exterior surface of steam-pipe, will warm 
 two hundred cubic feet of space. A larger 
 allowance, however, of steam-pipe is usually 
 given. Mr. H. Houldsworth, in the mill 
 at Anderston, has about one hundred and 
 seventp-nine cubic feet of space, to one su¬ 
 perficial foot of external surface of steam-- 
 pipe. Messrs. Kennedy and Watt af 
 Johnston, allow about one hundred and 
 sixty-eight feet. At Catrine, about two hun¬ 
 dred. But the temperature in those mills, 
 is much greater than is required for common 
 purposes, being from 70 to 85 degrees of 
 Fahrenheit. (See Note B.) Mr. Macnaught 
 has lately warmed a small chapel at Port- 
 Glasgow, to a comfortable temperature, by 
 oste foot surface of steam-pipe to four hundred 
 cubic feet of space. 
 
EFFECTS OF HEAT. 163 
 
 137. In the above examples, the steam 
 used, is about the strength usually employed 
 in Messrs. Boulton and Watt’s engines *. 
 Stronger steam would, no doubt, emit 
 more heat from a given surface of steam- 
 pipe, but it -would be difficult in that case, 
 to keep the joints steam-tight. 
 
 138. The nature of the building ought 
 first to be considered, whether much exposed 
 to cold winds, whether it be closely finished, 
 whether there be much wall, in proportion 
 to its capacity, whether the temperature 
 required, be moderate or high. These 
 circumstances being taken into considera¬ 
 tion, a judgement may be formed of the 
 proportion of steam-pipes, from what has 
 been ascertained to be sufficient in existing 
 cases. (See Note B.) 
 
 * That is, the safety-valve on the boiler to be loaded to about 2^ Kb, 
 to th& square inch. 
 
J64 
 
 EFFECTS OF HEAT. 
 
 SECTION III. 
 
 Of the Substance, and Surface of the Steam-pipe. 
 
 139. In order to save expence, pipes of 
 tin-plate have been tried, in preference to 
 cast-iron. It was supposed too, that from 
 its thinness, it would emit the heat more 
 rapidly than cast-iron. Upon the same 
 idea, thin copper pipes* were also tried 
 Contrary to expectation, however, it was 
 soon found, that the same surface of cast- 
 iron gave out much more heat, than eitlier 
 the tin-plate or copper. 
 
 140. Mr. H. Houldsworth made some 
 experiments to ascertain the difference 
 between tin-plate and cast-iron, with respect 
 to their effects in emitting heat; and found, 
 by measuring the quantity of steam con¬ 
 densed in equal lengths ft pipe, or, in other 
 
 
words, measuring the water of conden¬ 
 sation, (Art. 45,) that, taking the effect of 
 tin-plate in emitting heat as one, the effect 
 of cast-iron was equal to two and a half*, 
 
 ' 141. One of the apartments of the 
 Adelphi cotton-mill, Glasgow, which had 
 steam-pipes made of tin-plate, was not 
 found so warm as was required. When 
 this occurred, my attention was directed 
 to some of Professor Leslie’s experiments 
 on heat, this induced me to try the effect 
 of painting them black; the increase of 
 heat, from painting, was great beyond ex¬ 
 pectation. 
 
 142. This trial led me to suspect that the 
 greater effect of cast-iron arose, notffrom 
 the nature of the substance, but from the 
 
EFFECTS OF HEAT. 
 
 colour and nature of the surface. I therefore 
 had some experiments made to ascertain 
 this fact The results were sufficient for 
 my purpose at the time; but it were to be 
 wished, that the subject might be examined 
 by others with still greater accuracy. It 
 appeared, that when equally dark in colour, 
 and when the surface was equally rough, 
 tin-plate emitted heat as rapidly as cast- 
 iron f. 
 
 143. Cast-iron, however, has been found 
 much more durable, and convenient, in 
 its application, than other metals, which 
 have been tried. And it appears, when 
 durability is required, that it is the only 
 substance which seems properly applicable 
 to the purpose. Indeed it has been adopt¬ 
 ed in most of the late cases of warming 
 
 •These experiments were made somewhat in the manner of those 
 of Profesor Leslie. 
 
 There was a canister having four equal sides, three of which were 
 of tin-plate, and one of cast-iron. This canister was filled with hot 
 water, and an air thermometer indicated the temperature. 
 
 f Whether this effect proceeded from the jomt operation of colour 
 
 not ascertain.* Mr. Houldsworth tried cast-iron pipes painted various 
 colours, but found no difference of heat. (Art. dO). 
 
EFFECTS QF HEAT. 
 
 167 
 
 by steamSome, nevertheless, still pre¬ 
 fer tin-plate pipes, as being cheaper, more 
 speedily erected, and, when painted, as 
 effective in emitting heat. 
 
 144. With regard to the thickness of 
 the pipes, I do not suppose that this is to 
 be limited but by expence; for a thick pipe, 
 acting as a reservoir of heat, preserves a 
 more uniform temperature than a tliin one. 
 It is xtsual, however, in order to save expence, 
 to make them as thin as they can be con¬ 
 veniently cast, which may be from a half 
 to three-fourths of an inch. Professor 
 Leslie obligingly suggested to me, that 
 whenever the steam tubes come In contact 
 with the walls of a building, in order to 
 save the heat, a piece of tin-plate should 
 be interposed, (Art. 90.) 
 
 ind becomes no longer steam-tight. When steam-pipes are made of 
 inwards, to allow the air to rush in, should a vacuum take place in the 
 pipes have often suddenly collapsed. In cast-iron pipes such valves are 
 
EFFECTS OF HEAT. 
 
 ie§ 
 
 SECTION IV. 
 
 General Observations 7-especting the Dh-ection and 
 Arrangement of the Pipes. 
 
 145. In the arrangement of steam-pipes, 
 one of the greatest difficulties which occurs, 
 proceeds from the expansion of the metal. 
 —When the pipes are single, this is easily- 
 overcome; but where pipes are connected 
 at various angles, the principal difficulty is, 
 at the same time, to preserve the joints, 
 and give liberty for expansion. 
 
 146. To give some idea of the effect of 
 the heat of steam, in producing expansion, 
 I may mention, that a copper steam-pipe 
 160 feet long, was two inches longer when 
 filled with steam, than when cool; and 
 that ill practice., the expansion of steam-pipes of 
 oast-iron may be taker, at about one-tenth of an 
 inch., in ten feet of length. 
 
 147. “ Brass expands about one hundred 
 thousandth of its length, for each degree 
 of Fahrenheit; copper and gold a little less; 
 
HEATING BY STEAM. 169 
 
 silver somewhat more; iron and steel, about 
 two-thirds as much; tin, one-third more; 
 and lead and zinc about half as much 
 more (See Art. 28, 37.) 
 
 148. Count Rumford, in warming the 
 Lecture-Roona of the Royal Institution, by 
 steam, used drums of thin copper at the 
 terminations of the pipes; the heads of 
 these drums were about three, feet in diam¬ 
 eter, and yielded to the expansion of the 
 pipes. This plan, however, in most sit¬ 
 uations, would require too much space, 
 and be attended with too much expence. 
 
 149. When a straight pipe, filled with 
 steam, stands in a vertical position, it is 
 equally heated all round, and expanding, 
 equally, continues to be straight, but wheii 
 it lies in a horizontal direction, the upper 
 side becomes the hottest, and expanding 
 more than the lower, bends the pipe, which 
 in some cases endangers the joints. Mr. 
 Dalton, in a letter of the 14th .Tune, 1808, 
 
 * Young’s Nat. Phil. voL i. p. 64S. 
 
 y 
 
170 
 
 HEATING BY STEAM. 
 
 ■with which he favoured me, respecting my 
 pamphlet on warming buildings by steam, 
 says, “ I do not feel convinced of the ad¬ 
 vantages of vertical pipes, they must difiiise 
 less heat, having a hot current of air sweep¬ 
 ing them. Could not the bending of the 
 horizontal pipes, by unequal temperature, 
 be prevented by soldering a small tin-plate 
 to the upper surface of the pipe. This 
 would take the excess of heat from the 
 upper surface and dissipate it.” 
 
 Since publishing the pamphlet above 
 alluded to, experience and reflection have 
 convinced me of the justice of Mr. Dalton’s 
 observations, and I find it is only in case 
 of joints made with flanches of great dia¬ 
 meter, that there is any danger of their 
 breaking in a horizontal position from, 
 unequal expansion When air is heated, 
 becoming more rare, it has a tendency to 
 
 • In a mill which Mr. Houldsworth has heated by very thin cast-iroa 
 
HEATING BY STEAM. 
 
 171 
 
 ascend, horizontal pipes should, therefore, 
 when practicable be placed near the floor, 
 (Art. 89). 
 
 150. In arranging steam-pipes, two 
 points require considerable attention: Firsts 
 conveniently to expel the air; and, secondly^ 
 to take off the water resulting from the 
 condensation of tlie steam; which, to avoid 
 circumlocution, we shall call the water of 
 eondensatioju 
 
 In regard to the first point, the steam, in 
 entering the pipes, may be considered as a 
 kind of a piston, driving the air before it: 
 for the steam and air mix very imperfectly 
 in the pipes, and there appears almost a 
 distinct line between their surfaces. This 
 principle should therefore be kept in view, 
 in fixing upon the place of the opening for 
 allowing the air to escape, while the pipes 
 are filling. One or more passages is like¬ 
 wise necessary, after the pipes are filled, 
 in order to show a small portion of steam 
 constantly to escape, to keep up the heat 
 in the pipes. For if this be not done, air 
 will accumulate, and occupy the place of 
 the steam. 
 
172 
 
 HEATING BY STEAM. 
 
 151. With regard to the second point, 
 when it can conveniently be done, it is 
 better to make tlie water of condensation^ to 
 run in the same direction with the steam. 
 Indeed, in a horizontal pipe, the steam will 
 drive the water before it, and will do so 
 when the internal diameter does not exceed 
 2l inches; even if the pipe should have a 
 considerable acclivity. Great care, how¬ 
 ever, should be taken, to prevent the water 
 from lodging in any part of the pipes. 
 From want of due attention to this circum¬ 
 stance, accidents have not unfrequently 
 happened. The water remaining in the 
 pipes after they become cool, keeps one 
 part of them cold. The consequence is, 
 that next time the steam is let into the 
 pipes, the regular expansion is prevented, 
 some part of the pipe cracks, and a violent 
 explosion takes place, racking the joints, 
 to a considerable distance in every direc¬ 
 tion, from the place of explosion, 
 
 152. In most cases, it is attended with 
 least labour and expence, to place the pipes 
 in the horizontal direction. 
 
HEATING BY STEAM. 
 
 173 
 
 SECTION V. 
 
 Of the Methods of Connecting the Steam-Pipes. 
 
 Method 1. Figure 1. 
 
 153. Represents the method of con¬ 
 necting pipes by means of fianches. A 
 and B a.re the pipes, the projecting parts 
 CD, are called the fianches. 
 
 The junctures are secured by Interposing 
 rope-yarns, or some other pliant substance, 
 and iron-cement, and then screwing up 
 the whole by means of the screw-bolts 
 EE, &c. In all cases where bolts are used 
 in steam-pipes, they ought to be carefully 
 lapped with rope-yarn. 
 
 Ohses'vations. 
 
 When the pipes are horizontal, from in¬ 
 equality of expansion, the fianches are liable 
 to be broken, or at least to leak at the bolt 
 holes. For vertical pipes, they may often 
 be applied with advantage. This seems 
 to have been one of the oldest methods in 
 use, for the purpose of connecting cast-iron 
 pipes, (See Briidoi^^rebr-FiydnraliqHe^. 
 
174 
 
 HEATING BY STEAM. 
 
 N. B. All the observations which are 
 here made on the modes of connecting 
 pipes, relate to the conveying of steam only. 
 
 Method 2. Figure 2. 
 
 154. Represents a spigot and facet joint. 
 The juncture ,is secured by iron-cement, 
 to fill the space between the spigot AB, 
 and the facet CD. 
 
 Observations. 
 
 Spigot and facet joints do very well in 
 most cases, but there have been instances 
 of facets bursting from the greater expan¬ 
 sion of the spigots. The risk of this 
 accident is increased, by increasing the 
 space for the cement. 
 
 Method 3. Figure 3. 
 
 155, This figure represents a thimble 
 joint, which is secured in a similar manner 
 with method 2, 
 
 Observations. 
 
 This is a very convenient mode of join¬ 
 ing steam-tubes. If a thimble burst, it is 
 
HEATING BY STEAM. 
 
 175 
 
 easily renewed, and any one pipe may be 
 moved without disturbing the rest, which 
 cannot be done by method 2. Thimbles 
 are often used also to repair spigot and 
 facet pipes; when the facets break, spme^ 
 times it is convenient to make the thimbles 
 in two parts, as represented by No. 4. 
 Fig. 3. It occurs to me, that it would be 
 an improvement to make the thimbles of 
 plate-iron, leaving but a small space for 
 the cement. On this plan, the expansion 
 would be more equal, and the risk of the 
 joint being injui'ed, of course, much 
 lessened. 
 
 Method 4. Figure 4. 
 
 356. Represents a mode of connecting 
 spigot and facet pipes, where they are to 
 have a turn or angle. 
 
 Observations. 
 
 This method is simple and convenient, 
 when the place where the turn is required 
 is previously known, and the pipes cast 
 accordingly. 
 
176 
 
 HEATING BY STEAM. 
 
 Method 5. Figure 5. 
 
 157. Represents what is called the 
 saddle joint, used for taking off a branch 
 The branch has a piece AB formed on 
 its- end, which fits round one-half of the 
 outside of the pipe from which it is to 
 spring. CD is called the saddle which 
 fits round the other half of the pipe. 
 Two screwed hoops FG FG, embrace the 
 saddle, and the part AB, and cement 
 being interposed, they serve to secure the 
 whole. 
 
 ObsetX'ations. 
 
 By this method a branch may be formed 
 on any part of a pipe, by cutting a hole 
 there, and applying the joint to that place. 
 This easy method of applying a branch is 
 often of great use in practice, and the hoops 
 make it very secure, without the disadvan¬ 
 tage of bolt-holes in the cast-iron. 
 
 158. Where there is much risk of the 
 inequality of expansion, the joints at certain 
 places, should be secured by a soft stufiing 
 of hemp or cotton, and tallow; but in most 
 
HEATING BY STEAM. 177 
 
 cases, the joints may be made with iron 
 cement *. Lead has been tried for making 
 the joints, instead of iron cement, though 
 easy of repair, the lead soon gets loose by 
 alternate expansion and contraction. 
 
 1 59. At Butterly Iron-W orfcs, Derbyshire, 
 there is a very good plan of a joint, which 
 has been in use about 7 years, and during 
 the whole of that period, it has continued 
 tight and required no repair. It operates 
 for the expansion of a pipe conveying steam 
 about 40 yards, which makes it yield back¬ 
 ward and forward about % of an inch'. 
 The two adjoining ends of the pipes^A and 
 B, are turned true on the outside, and have a 
 thimble CDEF, with tin interposed between 
 it and the pipe which being less liable to 
 expansion than lead, has continued durable, 
 and still fits well to the turned parts of the 
 pipe, which work in it like a piston in a 
 cylinder, (See Fig. 6). 
 
 • This cement is composed of 40 Ihs. iron Ijorings, 1 do. salamoniac, 
 do. sulphur, well mixed together, and beaten like putty. 
 
 Much sulphur is hurtful, rendering the composition brittle. When, 
 
 the joints, before the steam is applied, a smaller proportion of sulphur 
 ■ than the above, may witli advantage be adopted. 
 
 Z 
 
178 
 
 HEATING BY STEAM. 
 
 Method 6. Figure 7. 
 
 160. Represents the method of making 
 joints, on vertical pipes, when they are used 
 as pillars for supporting floors. The ends 
 are turned to fit each other, and iron cement 
 is interposed. The weight is then suflicient 
 to secure the joint. 
 
 Observation. 
 
 No. 2. is only used when there is not 
 room for the projecting part on the outside 
 as in No. 1. which is preferable when 
 circumstances will permit. 
 
 161. Before putting up any of the steam- 
 pipes, they should be proved to be solid, by 
 the usual process of forcing water into them. 
 
HEATING BY STEAM. 
 
 179 
 
 SECTION VI. 
 
 Description of Boiler for generating Steam, mth 
 Apparatus for supplying it mth Water, regulat¬ 
 ing the Damper, ^c. 
 
 162. ABCD Fig. 8. represents the boiler 
 which is kept in a state of ebullition, by 
 means of a furnace and flues, as represented 
 in the figure, but I shall not at present enter 
 upon the subject of what is called hanging 
 of boilers. 
 
 Apparatus for supplying Wafer. 
 
 163. E the float which is usually made 
 of stone, but which has a balance-weight, 
 F, so as to make it act as if it were specif¬ 
 ically lighter than water. The float E 
 swims on the surface of the water in the 
 boiler, and by means of the wire EG is 
 connected with the lever GH, from which 
 by another wire IK, there is a communi¬ 
 cation with the valve K. The valve K is 
 situated in the bottom of a small cistern, 
 which is constantly supplied with water 
 by a pump, or otherwise. 
 
180 KEATING BY STEAM. 
 
 When there is a sufficiency of water in 
 the boiler, the valve K I'emains shut. But 
 suppose the water in the boiler to fall too 
 low, we shall see what takes place. The 
 float E sinking along with the water, by 
 means of the intermediate parts already 
 described, opens the valve K, and allows 
 the water to get through the valve, and 
 down the pipe KLMN into the boiler, until 
 it again raise the surface of the water, and 
 along with it the float E, which, of course, 
 again shuts the valve K, and thus prevents 
 the further admission of water, until it 
 be again required. 
 
 Apparatus for Regulating tlie Damped'. 
 
 164. Connected with the pipe KLMN is 
 another, but smaller pipe, MNOP, which 
 reaches, usually, within about 12 inches of 
 the bottom of the boiler. 
 
 In the pipe KLMNO there is a hollow 
 float-vessel Q, which is suspended by a 
 chain QR from the pulley S. The vessel 
 Q has liberty to rise and fall freely in the 
 pipe, which liberty also allows the water 
 
HEATING BY STEAM. 181 
 
 from the feeding-valve K, to escape past 
 , its sides, and so into the boiler. 
 
 From another pulley T, the damper W 
 is suspended by another chain TW. 
 
 While the fire is not too violent, the float- 
 vessel Q remains at the bottom of the 
 pipe KLMN, but suppose the fire to become 
 too strong, then the steam pressing on the 
 surface of the water in the boiler, forces 
 part of it up the pipe MNOP, which raises 
 the vessel Q, and by means of the inter¬ 
 mediate parts already described, depresses 
 the damper W, and so, by narrowing the 
 passage for the smoke, checks the draught 
 of the furnace, and, of course, damps .the 
 fire. 
 
 Safety Valves. 
 
 168. In order to prevent accidents, there 
 is a valve a which opens by the elasticity of 
 the steam, when it exceeds about lbs. 
 upon the square inch, a b is the pipe 
 which conveys the steam into the building. 
 There are also valves placed on or near the 
 
182 
 
 HEATING BY STEAM. 
 
 boiler, which open inwards, to prevent 
 accidents from a partial vacuum taking 
 place in the pipes, or boiler. 
 
 Gmge-Cocks, 
 
 166. c and d are the guage-cocks. c 
 communicates with a short pipe, which 
 terminates a little above the proper surface 
 of the water. There is another pipe from 
 which terminates a little below that level. 
 Accordingly, as water or as steam forces 
 through either of those cocks, the keeper 
 of the boiler is enabled to judge of the 
 height of the water within the boiler. 
 Besides the guage-cocks, a glass tube is 
 sometimes used, which shows to the eye, 
 the height of the water in the boiler. The 
 tube is fixed on the outside of the building, 
 and communicates with the boiler, by means 
 of two pipes, the one under the proper 
 level of the surface of the water and 
 the other above it. 
 
 Contrivances to give an Alarm 'when the Water 
 in the Boiler falls too Low. 
 
 167. For this purpose, is sometimes used 
 a pipe of about 24 inches diameter, reach- 
 
HEATING BY STEAM., 
 
 183 
 
 ing from a little way below the proper 
 level of the surface of the water, to about 
 9 feet above the upper part of it. Its upper 
 termination is like an organ pipe. Should 
 the water, therefore, fall too low, the steam 
 rushes through the pipe, and makes a noise 
 which alarms the whole neighbourhood, 
 and so may prevent the bottom of the 
 boiler from being burnt out, an accident, 
 by no means unfrequent. Other means 
 have also been proposed for the same pur¬ 
 pose, such, for instance, as working a stop¬ 
 cock by a float, which, when the water falls 
 too low, would allow the steam to blow 
 into a Boatswain’s whistle. 
 
184 
 
 HEATING BY STEAM. 
 
 SECTION VII. 
 
 168. It may be here observed, in general, 
 with respect to syphons, 1st, That they 
 should have a pressure of water, of at least 
 9 feet in them, in order to prevent the 
 water from being thrown out of them, 
 which would be the case, with a small 
 pressure, more particularly as the water is 
 liable to sudden oscillations. 2d, That 
 they should be wide enough to discharge 
 the water with ease. 3d, That they should 
 be in situations protected from the cold, 
 there having been instances of their being 
 rendered ineffectual from the water freez¬ 
 ing in them. A stop-cock for letting off 
 the air is commonly placed between the 
 steam-pipes and the syphon. Sometimes 
 there is a small hole (the size of a pin) 
 made in that part of the stop-cock which 
 is nearest the steam-tubes, in order that 
 there may always be a small quantity of 
 steam escaping to prevent accumulation of 
 air, in any part of the pipes. 
 
HEATING BY STEAM. 
 
 185 
 
 It frequently occurs, that proper depth 
 cannot conveniently be obtained for a 
 syphon. In that case, a valve to open by 
 a float-ball, has been applied. The valve 
 remains shut, until the water of condensation 
 begins to accumulate, which raises a hol¬ 
 low copper ball attached to the top of the 
 valve_, and allows the water to escape. A 
 syphon is, however, preferable wherever 
 depth for it can be obtained, being much 
 more simple, and less liable to be put out 
 of order. 
 
 ABC, Fig. 9. represents a syphon. The 
 water of condensation, which accumulates in 
 the steam-pipe CD, escapes at A. E is 
 the stop-cock for allowing the air to escape 
 by the pipe EF. EG is a smaller pipe, 
 which communicates with a very small 
 hole between the stop-cock and the steam- 
 
 r omitted to mention in its proper place, what is called the 
 It is a small iron syphon containing some inches of mercury in its bended 
 
 with the boiler., or some part of the sieam-ftfa. The other leg commun¬ 
 icates with the atmosphere, and has a small wooden rod in it, which 
 being raised or depressed, indicates the di/Ferent degrees of density of 
 e steam-gauge is represented by Fig. ff, Plate 2. 
 
 A a 
 
 
186 HEATING BY STEAM. 
 
 pipe CD, and allows a very small quantity 
 of steam constantly to escape, as was men¬ 
 tioned in this Section. 
 
 A syphon of this description, with a wide Bore, may often with 
 
HEATING BY STEAM. 
 
 IS1 
 
 SECTION VIII. 
 
 Description of some Cases, of the Direction and 
 
 Arrangement of Steam-pipes in Actual Use *. 
 
 169. Having made some general observ¬ 
 ations, respecting the direction and arrange¬ 
 ment of steam-pipes,—having considered 
 the various methods of connecting them, 
 and having described the boiler and its 
 apparatus, it may now be proper to notice 
 the direction and arrangement of the pipes, 
 in several cases, in actual use, and, as we 
 proceed, to make some observations on each 
 of these arrangements. 
 
 Arrangement I. for Heating a Cotton-Mill. 
 
 170. A horizontal pipe conveys the steam 
 from the boiler into the mill, connected 
 with a vertical pipe reaching nearly to the 
 ceiling of the uppermost room. 
 
 In each floor there is a horizontal pipe, 
 placed about 2 feet below the ceiling, and 
 
 * See also Note B, at the end of this Essay. 
 
188 HEATING BY STEAM, 
 
 each horizontal pipe has a stop-cock *, 
 where it branches ofF from the vertical 
 pipe. A syphon for conveying olF part of 
 the water of condensation, is placed at the 
 bottom of the vertical pipe. 
 
 Ohsenatiom. 
 
 At the Catrine cotton-works, where this 
 arrangement is adopted, the pipes have 
 their declivity towards the boiler, so that 
 the water of condensation, runs in an op¬ 
 posite direction to the passage of the steam. 
 A great proportion of it, finds its way 
 back to the feeding apparatus, by a small 
 pipe; the rest of it, is carried off by the 
 syphon. 
 
 At the further end of each horizontal 
 pipe, there is a small safety-valve opening 
 inwards, to prevent accidents from a vacuum 
 taking place within the pipes. That valve 
 also serves to allow the air to escape, while 
 the pipes are filling with steam. No prac- 
 
 • These stop-cocks at the Catrine works, are common inch-and-half 
 brass cocks. 
 
HEATING BY STEAM. 
 
 tical disadvantage is experienced, I am in¬ 
 formed, from all the steam which escapes 
 on'that occasion. 
 
 171. With horizontal pipes, it is very 
 common to have a smaller pipe, with a 
 Stop-cock from each, going through the 
 wall, to allow the air to escape; but from 
 what has been experienced at Catrine, this 
 precaution does not seem to be absolutely 
 necessary, nor yet (as is also common) to 
 take off the water of condensation from 
 the further ends of the pipes, in which case 
 the pipes incline in that direction. 
 
 172. I, however, think although less 
 simple, it is a more perfect arrangement to 
 take olF the water of condensation from 
 the further end of each horizontal pipe, 
 more pai'ticularly when such pipes are of 
 great length. The water of condensation 
 going before the steam, serves to warm 
 the lower part of the pipe, and make the 
 expansion of the upper and under parts of 
 it more equal, when die steam comes for¬ 
 ward. At Catrine, the tin-plate pipes, have 
 
190 
 
 HEATING BY STEAM. 
 
 been in use several years, and proprietors 
 think them sufiEciently durable. It is not, 
 however, the general opinion of those who 
 have tried both tin-plate and cast-iron; 
 but it is well worthy consideration, for 
 pipes of tin-plate, are much more speedily 
 erected, and are cheaper at the ordinary 
 prices, in the proportion of about 7 to IT. 
 One defect in this arrangement, as com¬ 
 monly executed, is having the pipes too 
 high above the floors; but they might be 
 placed near the floor, and yet arranged on 
 the same general principle. This arrange¬ 
 ment possesses a very considerable advan¬ 
 tage, for some purposes, over that about 
 to be described, viz. that each floor may 
 be heated separately. 
 
 Arrangement II. for Heating a Cotton-Mill. 
 
 173. The steam from the boiler, in this 
 arrangement, ascends in the vertical pipe, 
 to the highest story, where going along 
 the floor horizontally, to the further end, 
 it descends in a short vertical pipe to the 
 story below, where it is again carried along 
 
HEATING BY STEAM. 
 
 191 
 
 horizontally, and thus is made to descend 
 until it arrives at the bottom. There the 
 water proceeding from condensation, is 
 allowed to run off by a syphon, and the 
 air is allowed to escape by a stop-cock, 
 near the same place. 
 
 Observations. 
 
 This arrangement is exceedingly simple, 
 and is that adopted by Mr. T. Houldsworth, 
 in his cotton-mill (consisting of 8 stories) 
 at Manchester. Although the house be 42 
 feet wide, and the pipes on one side, the 
 heat is found sufficiently uniform, in every 
 part of the floors, for practice, and, in that 
 situation, it occupies little space. 
 
 It is a disadvantage in this arrangement, 
 that no part of the building can be heated 
 sepai'ately from the rest. But in a cottpn- 
 mill, this is not attended with much in¬ 
 convenience. 
 
 Messrs. Todd & Stevenson, at Glasgow, 
 have their mill heated by a similar arrange- 
 
192 
 
 HEATING BY STEAM. 
 
 ment, but the pipes are of tin-plate, and 
 were fitted up about the year 1793. 
 
 174. In arranging the steam-pipes for 
 Milgavie cotton-works, a similar mode was 
 followed. There, the steam-pipes require 
 about two hours in the morning, before 
 they are completely filled with steam. 
 
 Arrangement III. for Heating a Cotton-Mill. 
 
 175. In this arrangement, the principal 
 part of the tubes are vertical, and serve to 
 support the floor. 
 
 176. A horizontal pipe conducts the 
 steam from the boiler to the nearest ver¬ 
 tical pipe, and thence it is conducted by 
 the horizontal pipe, to the top of the new 
 vertical pipe, and so on, alternately ascend¬ 
 ing one pipe, and descending the next. 
 Below, it passes from one vertical tube to 
 another by the wider pipes. There are 
 smaller pipes to carry off the water of con¬ 
 densation, and being placed just below the 
 level of the under parts of the larger ones, 
 
HEATING BY STEAM. 
 
 193 
 
 they are kept always full of water, so as 
 to prevent the steam from passing through 
 them. At the farther end, the water of 
 condensation is let off by a syphon, and 
 the air by a cock or valve, which, in order 
 to allow the air to escape freely, should be 
 as large as the diameter of the steam-pipes. 
 If the number of pillars be not even, then 
 the air-valve should be at the top of the 
 last vertical pipe. 
 
 Observations. 
 
 This mode saves the expense of pillars, 
 for supporting the floors, but eveiy one of 
 experience, knows the disadvantage of hav¬ 
 ing any apparatus or piece of machinery, 
 so constructed as that, when any parti¬ 
 cular part of it is out of order, it cannot 
 be repaired without deranging the whole 
 system. 
 
 There are many mills, however, fitted 
 up on this plan, which give satisfaction to 
 the proprietors. 
 
 Messrs. Forbes, Low, & Go’s, great mill, 
 
 which is heated in this way, at Aberdeen, 
 
]94 
 
 HEATING BY STEAM. 
 
 requires about three quarters of an hour 
 to let off the air and fill the tubes with 
 steam. Messrs. William King & Co.’s 
 mill at Johnston, is also on that plan. 
 There the steam passes through about 400 
 feet of tubes, in 15 or 20 minutes. The 
 tubes should be equally wide throughout, 
 in order that they may fill with greater 
 facility. (See Note B). 
 
 D’sielling-Houses. 
 
 177. There are yet but few instances 
 of dwelling-houses heated by steam, nor, 
 perhaps, would it be eligible to heat small 
 houses separately by it, on account of the 
 trouble it would require to keep a small 
 boiler regularly supplied with water and 
 fuel. But where steam can be obtained 
 from a steam-engine boiler, or where a 
 number of neighbouring buildings could 
 be supplied from one boiler, much might 
 be saved in attendance and fuel, as well as 
 cost of apparatus. In cases where single 
 buildings are large, such as Inns, Hotels, 
 &c. steam might be applied with peculiar 
 advantage in heating the stair-cases, pas- 
 
HEATING BY STEAM. 195 
 
 sages, bed-rooms, &c. An eating-room 
 heated by an open fire only, is often 
 unpleasantly cold to those who sit near 
 the door, while it is oppressively warm 
 to those who sit near the fire. This 
 inconvenience might be remedied by the 
 use of steam. A very small open fire in 
 that case, would be sufficient to give a 
 cheerful appearance to the room. The 
 particular arrangements of the apparatus 
 proper for dwelling-houses, must de¬ 
 pend much on local circumstances. As 
 the steam may be admitted into vessels of 
 almost any form, the ornamental may be 
 combined with the useful. I am at pre¬ 
 sent, engaged in some experiments, with a 
 view to simplify such arrangements, but 
 am not yet ready to lay the result before 
 the public, 
 
 178. Mr. Lee of Manchester has his 
 dwelling-house heated by steam, conveyed 
 under ground from the boiler of a steam- 
 engine. The stair-case, lobby, and passages, 
 are heated by means of a steam cylinder, 
 placed vertically in the sunk story. The 
 
196 HEATING BY STEAM. 
 
 Steam cylinder is surrounded by a casing 
 of brick-work, leaving a space of about 
 two and a half inches all round, and hav¬ 
 ing openings below to admit air. This 
 casing is surrounded at some little dis¬ 
 tance, by another cylindrical wall, forming 
 what we may call the well. The coldest 
 air being the heaviest, falls to the bottom 
 of the well, and enters by the holes below 
 into contact with the cylinder, where, be¬ 
 coming heated and specifically lighter, it 
 ascends. This circulation of the same air, 
 in a very short time, makes the stair-case, 
 &c. comfortably warm. There is a valve 
 to regulate the admission of the steam into 
 the cylinder. There is also another valve 
 on the top of the casing of brick-work, to 
 regulate the transmission of the heated air. 
 It generally soon becomes so warm, that it 
 is necessary to shut one or other of these 
 valves. 
 
 The dining-room is heated by means of 
 two ornamental cast-iron vases filled with 
 steam, and the bed-rooms by steam-pipes 
 of the same material. 
 
HEATING BY STEAM. 
 
 197 
 
 It may not be improper to mention, 
 that the house is lighted, in a very elegant 
 manner, by coal gas. 
 
 179. In answer to some inquiries which 
 I made respecting heating of an inn at 
 Johnston, by steam, Mr. M‘Naught oblig¬ 
 ingly sent me the following letter: 
 
 Johnston, 1th Sept. 1809. 
 
 Dear Sir, 
 
 In compliance with your request, 
 I now send you a description of the Black 
 Bull Inn, as it is heated with steam.— 
 There is a boiler fitted up in the ordinary 
 way, except the furnace mouth, which 
 is made like a hopper, in order to hold 
 a considerable quantity of coal-gum * or 
 dross, and prevents frequent attention to 
 the fire, as there may be put in as much 
 at a time as will serve at least half a day, 
 and will need only to be stirred a little 
 with the pocker now and then. The un¬ 
 der flat is heated with triangular pipes, to 
 imitate a cornice, the place of which they 
 
198 
 
 HEATING BY STEAM. 
 
 occupy in one side of all the rooms; from 
 the metal cornices, a pipe is taken to the 
 upper rooms into a sort of chest, which 
 stands upon short feet similar to a desk, 
 and freely admits air below it. They are 
 ornamented in front similar to carron- 
 grates, &c. in some of the rooms there are 
 two, in others only one, of these chests, ac¬ 
 cording to the size of the rooms. As they 
 are yet hardly finished, and have been 
 tried only a few days, little can be said as 
 to the effect. Considering the doors being 
 so frequently opened, &c. a large portion of 
 heated surface has been allowed, about 1 
 foot to 100. It seems to me, that the 
 house will be too warm, but it is impos¬ 
 sible to judge accurately till cold weather 
 commences. 
 
 The reason for keeping the under pipes 
 so high as the cornice, was to get the con¬ 
 densed water back into tlie boiler, as there 
 is no regular supply, what they have is got 
 from the roof, and kept in a number of 
 casks supported in a row above the boiler. 
 And by using tbe bot water from tbe 
 
HEATING BY STEAM. 199 
 
 pipes, there is only the waste of evapora¬ 
 tion tor to keep up. There is a steam 
 kitchen connected with the boiler, in a 
 pretty advanced state. 
 
 Among other advantages, a dinner or 
 plates, &ZC. may be kept warm by setting 
 them on the top of the chests, and placing a 
 cover over them. It will also save a servant, 
 during winter at least, and as there is 
 more power in the boiler than necessary, 
 some of the neighbours have been treating 
 to be heated from it.—This you will see 
 will become common in a short time. I am, 
 Dear Sir, 
 
 Yours, &c. 
 
 Public Buildings. 
 
 180. In the year 1801, Count Rumford, 
 arranged the apparatus, for heating the 
 Great Lecture-room of the Royal Institu¬ 
 tion by steam, in the following manner; 
 
 The steam is generated in a boiler on 
 
 ihe ground floor, and is conveyed by a 
 
200 
 
 HEATING BY STEAM. 
 
 copper pipe into the Lecture-room. There, 
 it divides into two branches, and passes 
 horizontally under the seats. 
 
 In order to counteract the expansion 
 of the pipes, there is a drum of thin cop¬ 
 per, placed in the middle of each tube. 
 The water of condensation is carried off 
 from the lower part of each drum by 
 small tubes, and conveyed back to the 
 boiler. 
 
 The general arrangement here seems 
 good. The lower part of the room being 
 heated, the other parts must of course, be 
 sufficiently warm. The plan of the expan¬ 
 sion drums, although ingenious, is objec¬ 
 tionable on account of expense, as well as 
 on accoimt of their occupying a very large 
 space. 
 
 We are yet much in want of examples 
 of heating public buildings by steam, but 
 it is highly probable that it will soon be¬ 
 come more general. The mode in which 
 Mr. Lee heats his stair-case, might perhaps 
 
HEATING BY STEAM. 
 
 201 
 
 be applicable with advantage in many 
 cases of public buildings. Much of what 
 is said respecting dwelling-houses may be 
 applied here. 
 
 Bath. 
 
 179. The late Mr. Boulton of Soho, was, 
 I believe, the first who used steam for 
 heating the water for a warm bath, which 
 I am told, gave rise to the method of 
 heating the vats, &c. of the dye-house of 
 Messrs. Wormauld & Gott of Leeds. 
 
 At Helensburgh, the water for the warm 
 baths is, as usual, heated in a boiler, and 
 admitted as it is wanted. Steam from the 
 same boiler, serves also to heat the bath¬ 
 rooms, to each of which it is communicat¬ 
 ed by a small pipe, to a vertical tube of 
 tin-plate about 7 Inches diameter, and 4 
 feet long. 
 
 I shall not at present enter into the 
 details of heating water by steam, as that 
 subject may furnish matter for a separate 
 
General Explanation of Plate 2. 
 
 Fig. 1, represents the method of connecting pipes by 
 means of Ranches, (Art. 153). 
 
 Fig. 2, spigot and faucet joint, (Art. 154). 
 
 Fig. 3, tkimilejoint, (Art. 155). 
 
 Fig. 4, a method of connecting spigot and faucet pipes, 
 where they are to have a round turn or an angle, (Art. 
 156). 
 
 Fig. 5, saddle joint, (Art. 157). 
 
 Fig. 6, slipping joint to allow the pipes to expand, (Art. 
 
 Fig. 7, methods of making joints on vertical pipes sup¬ 
 porting floors, (Art. 160). 
 
 Fig. 8, steam boiler with apparatus for feeding, &c. 
 (Art. 162). 
 
 Fig. 9, represents the mode of allowing the air to escape 
 by a pipe at the termination of the steam pipes, and of tak¬ 
 ing o£F the nuater of condensation by means of a syphon, 
 
 (Art, 168).- 
 
 END OF PART SECOND. 
 

 DRYING, 
 
 HEATING, 
 
 BY STEAM. 
 
 INTRODUCTION. 
 
 Hitherto, we have considered those 
 cases only where the temperature does not 
 exceed 70° or 80° of Fahrenheit’s ther¬ 
 mometer, and where heat only is required; 
 but there is another application of steam, 
 of which we come now to treat, I allude to 
 its use, as a substitute for drying-stoves. 
 
204 
 
 HEATING BY STEAM. 
 
 Steam was many years ago tried at 
 Leeds for that purpose; but, for reasons 
 with which I am unacquainted, the plan 
 was abandoned. 
 
 A method of drying certain kinds of 
 muslins, by wrapping them round cylinders 
 of tin-plate, has, for several years, been 
 successfully practised by bleachers, in the 
 vicinity of Glasgow. The first idea of 
 
 them, I believe was suggested by Mr. 
 
 John Burns of P^sley,in conversation with 
 Mr. Laird, and Mr. Tennant, now of Glas¬ 
 gow. It was first put in practice by the 
 last mentioned gentleman, at the Darnly 
 bleaching works, about the year 1793, 
 about twelve months before it was adopted 
 at any other work. A description of this 
 method of drying muslins, may be seen 
 in “Dr. Ree’s Cyclopedia’’article, “Bleach¬ 
 ing.” Steam-rollers have also been suc¬ 
 cessfully used by calico-printers, for drying 
 their goods; but somewhat different in 
 their modification, from those above al¬ 
 luded to. 
 
HEATING BY STEAM. 
 
 181. Mr. Lounds of Paisley, I believe, 
 was the first who succeeded in using steam 
 as a substitute for a drying-stove to dry 
 goods, stretched on frames. This he has 
 done these several years, for the finer kinds 
 of muslins. 
 
 The temperature required for such goods, 
 however, is much lower than that required 
 for drying the thicker kinds of cotton-cloth, 
 9lich as ckequered Kandkerckiefs, called 
 pullicates. Messrs. Muir, Brown, & Co. 
 at Glasgow, were the first who succeeded 
 in the application of steam, for this pur¬ 
 pose, and also for drying dyed and bleached 
 yarns, where the temperature required is 
 still higher. They made the first trial of 
 their drying-rooms on March 26th, 1808. 
 
 Mr. Muir informs me, that though they 
 formerly gave out their pullicates to be 
 bleached, by some of the best bleachers in 
 this part of the country, that they never 
 had the colours of their goods in the same 
 perfection which they now have, and which 
 improvement they attribute entirely to the 
 
206 
 
 HEATING BY STEAM. 
 
 superior efiect of the steam, and that the ' 
 more experience he has, he is the more 
 convinced of this advantage from the 
 steam-heat. 
 
 I apprehend the superior effect, with 
 regard to colour, of this mode of drying, 
 arises from the difficulty of raising steam- 
 heat to such a degree as to be injurious; 
 as well that no gas which can he hurtful 
 to the colours, is emitted from the steam- 
 pipe. In drying-stoves, on the contrary, 
 the heat is often raised too suddenly to a 
 very high temperature, which gives a harsh 
 feel to the goods; and in such stoves, the 
 air is often much injured by gas emitted 
 from the coaclde and the flues, which must 
 certainly have a great, influence on the 
 colour of the goods,* 
 
HEATING BY STEAM, 
 
 207 
 
 Mr. Muir gives me the following fur¬ 
 ther information, which must be agreeable 
 to every friend to humanity, that the peo¬ 
 ple who now work in his drying-rooms, 
 were formerly employed in working in a 
 stove heated in the common way, at which 
 time, they had a very emaciated unhealthy 
 appearance; but since they have been 
 employed in the rooms heated by steam, 
 they have become healthy, and their aspect 
 has changed most materially for the better. 
 
 182. About this period, Mr. Richard 
 Gillespie, of Anderston, notwithstanding 
 the prejudices of other calico-printers, who 
 predicted that the heat proceeding from 
 steam-pipes, was not of a kind that would 
 
HEATING BY STEAM. 
 
 ever answer in the practice of calico-print¬ 
 ing. They required, they said, a dry heat^ 
 which they conceived could never proceed 
 from steam, a fluid moist in its own nature, 
 forgetting that heat is not altered by being 
 combined with other kinds of matter, and, 
 that in passing through the pipes, if pro¬ 
 perly executed, the heat must leave the 
 moisture behind. Mr. Gillespie, notwith¬ 
 standing those prejudices, made the attempt 
 first, in his copper-plate house, and suc¬ 
 ceeded to his most sanguine wish. His 
 success in this instance, prompted him to 
 apply steam to his block-printing shops, 
 also in which, he has been equally suc¬ 
 cessful. 
 
 Previously to these applications, besides 
 heating his warehouse, he had applied it 
 to the heating of his calenders. For which 
 purpose, the steam is conveyed about 93 
 yards under ground 
 
 * I believe the late Mr. John Miller of Glasgow, was the first who 
 applied steam to the heating of a calender, which he did in the month 
 of July 1805. 
 
 This mode of heating calenders by steam, is found a very great 
 improvement, not only as it saves time, but improves the appearance 
 of the goods. When heated with red-hot iron heaters, the goods had 
 comparaUTely a harsh impoverished, dry, brittle feel. 
 
HEATING BY STEAM. 
 
 Messrs. Leys, Mason & Co. of Aberdeen, 
 also about this time applied steam (on 
 principles similar to Messrs. Muir, Brown, 
 & Co.) to the purpose of drying cloth at 
 their bleaching’works. 
 
 Dd 
 
210 HEATING BY STEAM. 
 
 SECTION I. 
 
 CASE L— Btying-House. 
 
 183. Consists of a room 8 feet high, 
 of an irregular figure, containing about 
 9472 cubic feet of space, and is heated by 
 means of horizontal steam-tubes of tin¬ 
 plate, about 2 feet from the floor. These 
 tubes are arranged in two separate groups, 
 so as to be immediately under two frames, 
 on which the goods are stretched. 
 
 Cubic feet of «pace, -.-.9472. 
 
 Suifece of tube,---S8J.1 feet. 
 
 Space heated by one foot surfece of tin-tube, 16.2 cub. feet. 
 
 But as cast-iron emits %■ times more heat 
 than tin-plate, (Art. 140.) the less tube 
 would have served, in which case, the 
 space heated by one foot surface, would 
 be represented by 21 times 16. That is, 
 40 cubic feet of space heated by 1 super¬ 
 ficial foot of cast-iron, temperature 90°. 
 
HEATING BY STEAM. 
 
 211 
 
 Observations. 
 
 In summer, this room is sometimes at 
 100°; in winter, generally 90°. 
 
 On the 18th of November, 1808, it was 
 only 80°, the external ah' at the time being 
 42°, being a difference of 38 between the 
 external and internal air. 
 
 The goods dried here, are thin muslins, 
 stretched on frames, the air being agitated 
 by a pendulous fan. 
 
 It is employed first, strictly as a heating 
 stove, and the windows kept all close shut, 
 until the vapour from the goods begins to 
 condense on the windows. As soon as 
 the steam begins to obscure the glass, the 
 attendants open them to let off the vapour, 
 and when that is done, they , shut them 
 again; thus alternately heating and venti¬ 
 lating. 
 
 This, mode appears to me exceedingly 
 judicious; formerly, there was no persua¬ 
 sion could make operatives see the pro¬ 
 priety of ventilation in a drying-stove. 
 
212 HEATING BY STEAM. 
 
 They now find that ventilation is neces¬ 
 sary to a certain degree, which degree Mr. 
 Dalton (in his Letter of 14th June, 1808,) 
 says, “ has not yet, I conceive, been de¬ 
 termined.” Query, Whether may not the 
 appearances on the glass, now mentioned, 
 serve as some indication of the degree? A 
 hygrometer might, pi'obably, be of very 
 great use in situations of this kind. (Art. 
 82.) 
 
 One of the most scientific and experi¬ 
 enced bleachers we have, informed me, 
 (April, 1806,) that stoves were much im- 
 proved,by admitting a more free circulation 
 of air, and, in that case, 80°, or even 70°, 
 was sufficient for pui-poses which required 
 100°, in a close house. 
 
 It is evident, that the heat operates on 
 the cloth, by evaporating the water, but 
 after it has thus suspended the moisture, 
 if it be not allowed to escape somewhere, 
 it must remain in the room, and retai'd 
 the process. In other words, it is' keeping 
 the goods in a damp, although warm, 
 atmosphere. 
 
HEATING BY STEAM. 
 
 213 
 
 CASE n.— Drying^House. 
 
 184. This drying-house is heated by 
 horizontal cast-iron steam-tubes, in such 
 proportion, that one foot surface, heats 
 about 80 cubic feet of space. 
 
 The steam is kept in tlie tubes in the 
 night, as well as in the day. 
 
 The temperature in November 1807, 
 was 100“. 
 
 CASE JR.—^Drying-Room. 
 
 185. In this case, there are two rooms 
 for drying by steam, the one for cloth, 
 and the other for yarn. 
 
 These rooms are both on tlie same floor, 
 one story above ground. The steam is 
 generated in a boiier, which supplies' a 
 steam-engine and . other purposes. That 
 for the yarn, requires to be considerably 
 hotter than that for the goods. 
 
 The whole of these steam-tubes are of 
 east-iron, eight inches external diameter. 
 
§14 HEATING BY STEAM. 
 
 and are joined by thimbles where they are 
 straight, by saddle joints at the branches, 
 and by spigot and faucet jomts at the angles. 
 (See Art. 154—157.) 
 
 The most of the joints are made with 
 iron cement (Art 158). Lead was tried for 
 some of them, but was found not to make 
 a lasting joint 
 
 The tubes are placed near the floor, in¬ 
 clining downwards as they recede from 
 the boiler. In order to allow them to move 
 freely in expanding and contracting, they 
 are supported by hollow cast-iron rollers, 
 which rest on blocks of wood, rounded in 
 a contrary direction on their under side, 
 which rests on the floor. Thus forming 
 a kind of universal joint. 
 
 Where the steam-tubes come in contact 
 with the walls of the building, pieces of 
 tin-plate are interposed, in order to save 
 the heat. (See Art. 90 and 144.) 
 
HEATING BY STEAM. 215 
 
 The rooms are both eight feet high. 
 The yarn-room contains 4,224 cubic feet 
 of space. 
 
 Cubic feet of space heated by 1 super¬ 
 ficial foot of steam-pipe, 16^. 
 
 Cloth room contains 5,952 cubic feet. 
 
 Cubic feet of space heated by 1 super¬ 
 ficial foot of steam-pipe, 23i4. 
 
 There is a valve, where the steam-con¬ 
 ductor branches off from the boiler, laden 
 just to that degree, that when the. steam 
 becomes weak, it shuts, and . allows the 
 whole of it to go to supply the steam- 
 engine. 
 
 Obsetvatims. 
 
 These rooms were first tried on the 
 26th March, 1808; the walls were then 
 damp, from having been recently plaistered. 
 
 The external air was-42°. 
 
 The cloth-room-91°. 
 
 The yarn-room-99°. 
 
216 HEATING BY STEAM. 
 
 The steam boiler is only kept boiling 
 during the day, and is rather small to 
 supply the various purposes to which it is 
 applied, so that the rooms are not kept nearly 
 so hot as otherwise they might be. There 
 are also several of the panes of glass 
 broken, and often a great deal of wet 
 goods in the rooms; but, notwithstanding 
 those disadvantages, the temperature is 
 generally from 86° to 96°. The yarn 
 room is commonly about 10° higher than 
 that for cloth. The former, in summer, 
 was often as hot as 120°. 
 
 Notwithstanding the lowness of the 
 temperature, these two rooms dry as much 
 goods, and with as few htads, as any stoves 
 of the same dimensions, even where the 
 temperature is much higher. And it is 
 pleasing to reflect, that the people working 
 in the steam rooms, are much more 
 healthy and comfortable, than those in 
 the contaminated air proceeding from 
 stoves, as commonly constructed for such 
 .purposes. 
 
HEATING BY STEAM. 217 
 
 The proprietors assure me, that they are 
 more and more convinced of the superior 
 effects of steam, with respect to the colour 
 and finish of the goods, as well as with 
 the much greater economy of the process; 
 and, that they are so much convinced of 
 the superior colour and finish, that al¬ 
 though it were at double the expense of stove 
 heat^ they would still use it in preference, 
 
 On the 14 th of January, 1809, the tem¬ 
 perature of the external air being 29°, 
 
 The cloth room was-86°. 
 
 The yarn room was-101°. 
 
 Although the windows were partly open, 
 and a great deal of wet goods in the rooms. 
 
 The attendants find here, that the ad¬ 
 vantage of a circulation of air, depends 
 very much upon the state of the weather. 
 When it is damp, they find it is best to 
 keep the windows shut, and to raise the 
 steam heat; but, on the contrary, when 
 the weather is dry, a free circulation of 
 Ee 
 
218 
 
 HEATING BY STEAM. 
 
 air is of much greater consequence than a 
 high temperature. 
 
 CASE rV .—Calico Printing. 
 
 186. The steam is generated in a boiler 
 
 of about twenty horses’ power, which sup¬ 
 plies a steam-engine of ten horses’ power. 
 The steam is conveyed about ninety-three 
 yards under ground, to heat two calenders, 
 and warm counting-houses and warehouses. 
 It also heats the copper-plate house, block¬ 
 printing shops, and heats water for the 
 processes of branning, dyeing, &c. 
 
 1. Copper-Plate House. 
 
 The copper-plate presses are driven by 
 the steam-engine, and stand in a room one 
 story above the ground. 
 
 About six inches from the ceiling, is a 
 horizontal steam-tube, six inches exter¬ 
 nal diameter. 
 
 The garret above the presses, is occupied 
 for drying the cloth, as it passes from the 
 presses; which arrangement allows the 
 
HEATING BY STEAM. 
 
 printers to work in a moderate tempera¬ 
 ture, while the goods are drying in a tem¬ 
 perature much higher. The garret is heated 
 partly from the heat which rises from the 
 press-room, and partly from a horizontal 
 tube, seven inches external diameter. 
 
 But, as there is a communication be¬ 
 tween the rooms, they ought to be taken 
 together. Therefore, press-room and garret 
 taken together, the space heated by 1 foot 
 surface of steam-tube is 181-cubic feet. 
 
 On the 12th February, 1808, the tem¬ 
 perature of the external air, early in the 
 morning, was 27°, about eleven o’clock, it 
 was 30°. 
 
 The press-room-64°. 
 
 The garret-73°. 
 
 Notwithstanding the coldness of the ex¬ 
 ternal air, tke cloth from the presses was 
 made, to use the overseer’s expression, bone 
 dry, and the operations going on to the 
 complete satisfaction of the proprietors. 
 
HEATING BY STEAM. 
 
 12th of March, 1808, the thermometer 
 in the garret, stood at 105°. 
 
 2. Block-Printing Shops. 
 
 The block-printing shops are each heated 
 by a horizontal steam-tube, Ilf inches 
 diameter, of cast-iron, about 21 feet from 
 each floor; and the temperature, when 
 there is a sufficiency of steam, is usually 
 about 80°. 
 
 Here 90 cubic feet is the space heated 
 by one foot surface of steam-tube. 
 
 Obsenations. ■ 
 
 This mode of heating for this kind of 
 printing, gives equal satisfaction with that 
 for the copper-plate department. 
 
 It is proper to have a boiler of sufficient 
 capacity, in order that the steam may be 
 used for all the various purposes to which 
 it is applicable, in the different processes 
 in calico-printing. In this particular case, 
 the proprietor informs me, that since he has 
 used steam as a substitute for stoves, &c. 
 the saving produced has been very great. 
 
HEATING BY STEAM. 
 
 221 
 
 SECTION II. 
 
 Of the d'ffereme of Temperature between the ex¬ 
 ternal Air and the internal Air of a Building 
 heated by Steam. 
 
 187. Hoping that it might be satisfac- 
 toiy to many, to know whether the differ¬ 
 ence of temperature between the external 
 and the internal air of a building heated by 
 steam, was nearly constant., and conceiving, 
 that it might lead to some useful inference, 
 I was Induced to have the subject experi¬ 
 mentally examined. This examination 
 Mr. H. Houldsworth had the goodness to 
 permit me to make at one of his mills in 
 Anderston; the result of which is given 
 in the following table. 
 
 From the table, it will appear that the 
 difference is far from being constant, and 
 that it is greatest when the air is coldest. 
 
HEATING BY STEAM, 
 
 Talk of the state of the Thermometer in the open 
 Air, and in a Cotton-Mill, the property of H. 
 Houldsxcortk, Esq. each day at \9. o’clock. 
 
HEATING BY STEAM. 
 
 223 
 
 SECTION III. 
 
 Of the proportion hct’ween the Surface of Steam- 
 Pipe, and the Heat produced. 
 
 188. It is of considerable practical im¬ 
 portance, to be able to calculate the quan¬ 
 tity of steam-pipe which will be necessary 
 to produce a given temperature. It must 
 be confessed, however, that such an estimate 
 admits not of absolute precision. 
 
 The temperature will, obviously, not 
 increase in a ratio nearly so high as the 
 increase of surface of pipe. For, suppose 
 a room already at 70°, and that, by means 
 of a cock or valve, we suddenly introduce 
 steam into another tube, which is equal to 
 that already producing the 70°, the differ¬ 
 ence of temperature between the external 
 and internal surfaces of the second pipe, is 
 much less than it was in the first. Of 
 course, the condensation must go on much 
 more slowly, and were the air at 112°, and 
 the steam of the same density as the 
 
224 HEATING BY STEAM. 
 
 atmosphere, no condensation at all could 
 take place. The facts which are collected 
 in the annexed table, will, however, enable 
 the practical reader to approximate toward 
 the truth; and he will there see, perhaps, 
 nearly the maximum temperature which 
 is to be expected in any case in practice, 
 where the rooms have but little ventilation. 
 Where the ventilation is great, it follows, 
 that the effect of the surface of steam-tubes 
 must be lessened. In this table, I would 
 beg leave to direct the reader’s attention 
 to the difference between the temperature 
 of the external and internal air, as being 
 likely to furnish a guide in calculating the 
 quantity of pipe requisite in any given 
 
 In order to form some idea of the greatest 
 heat which could probably be expected 
 from steam-tubes, when the surface should 
 be very great, I made tlie following experi¬ 
 ments, which were repeated, with nearly 
 the same results. These results are, for 
 the sake of bringing the whole of this part 
 of the subject into one view, given in the 
 
HEATING BY STEAM. 
 
 225 
 
 Experiment \st. 
 
 189. A cylindrical tin-plate canister, 
 two inches diameter, and five inches long, 
 with a small projecting rim at one end, to 
 receive a cork. A Fahrenheit’s thermom¬ 
 eter was inserted through the cork, so that 
 its bulb was nearly in the centre of the 
 canister. It may be proper to remark, 
 that the tin-plate was become dim, from 
 having been long exposed to the air. 
 
 This canister was plunged its whole 
 depth into boiling water. The thermom¬ 
 eter, which previously stood at 60°, rose 
 to 160°. The barometer stood at 29.5. 
 
 Observations. 
 
 In this and the following experiments, 
 upon emersing the canisters into the 
 boiling water, part of the air which was 
 expanded by the heat, escaped between the 
 cork and the thermometer. But this is 
 what must occur in practice on the great 
 scale, as the ratified air must escape from 
 an apartment, when it becomes heated. 
 
 F f 
 
226 
 
 HEATING BY STEAM. 
 
 The contents of the canister was 0.00909 
 cubic feet. 
 
 The surface exposed to the hot water, 
 
 0.2563 superficial feet. 
 
 Space heated proportionate to one super¬ 
 ficial foot of surface exposed to the hot 
 water, 0.035466. 
 
 Experiment 2d. . 
 
 190. The same canister, coated in the 
 inside with lamp black and size, all other 
 circumstances being as in the first experi¬ 
 ment, was immersed its whole depth in 
 boiling water. The thermometer rose to 
 190“.. 
 
 Ohsei'eations. 
 
 Here we see the increase of effect 30 
 degrees, occasioned by coating the surface 
 of the tin-plate with lamp black. (See 
 Art. 83.) 
 
 Experiment 3d. 
 
 191. The canister, all other circum¬ 
 stances as in experiment 2d, was half im- 
 
HEATING BY STEAM. 227 
 mersed in boiling water. The thermom¬ 
 eter rose to 176°. 
 
 Obsemtions. 
 
 The space heated proportionate to one 
 superficial foot of surface exposed to the 
 hot water, which, in this case, was double 
 that of experiment 2d, or 0.070932, which 
 alteration lowered the thermometer 24°. 
 
 ExperinKiit Mh. 
 
 192. A small canister of tin-plate, of 
 an elliptical form, about 2.75 inches deep, 
 having its greatest diameter 1.9 inches, 
 and its least 0.8. The tin-plate, as in the 
 cylindrical canister, was tarnished. A 
 thermometer was also inserted through a 
 cork. The canister being immersed into 
 boiling water, the thermometer rose to 
 190. 
 
 Experiment 5th. 
 
 193. The 4th experiment repeated, with 
 this difference only, viz. that the inside of 
 the canister was coated with lamp black. 
 The thermometer rose no higher than 
 190°. 
 
HEATING BY STEAM. 
 
 Observations on Experiments 4-th and 5th.. 
 
 In the 4th and 5th experiments, the con¬ 
 tents of the canister was 0.001899 cubic 
 feet 
 
 Surface exposed to thehot water, 0.107291 
 superficial feet 
 
 Space heated proportionate to one super¬ 
 ficial foot of surface exposed to the hot 
 water, .017699. 
 
 In so small a space, compared with the 
 surface, coating appears to have no influ¬ 
 ence on the projecting power, for the re¬ 
 sult, 190°, in both these experiments, is 
 the same. 
 
 We may infer from Experiments 3d, 
 4th, and 5th, that the maximum heat to he 
 produced hy steam, where the air is not confined, 
 is 190 degrees. 
 
HEATING BY STEAM. 
 
 229 
 
 194. Table shomng the Heat produced frm dif¬ 
 ferent Proportions of Steam-Pipe. 
 
 
 Cubic feet 
 warmed by 1 
 super, foot 
 of steam-pipe. 
 
 Ex- 
 
 Air. 
 
 n,T^r. 
 
 Difference 
 of temper- 
 
 Chapel at Port-Glasgow, 
 
 400 
 
 40 
 
 60 
 
 20 
 
 
 200 
 
 34 
 
 70 
 
 36 
 
 Case I. (Art. 183.) - 
 
 .40 
 
 34 
 
 90 
 
 56 
 
 Case II. (Art. 184.) - 
 
 80 
 
 34 
 
 100 
 
 66 
 
 Case III. (Art. 185.) 
 
 
 
 
 
 cloth-room, ... 
 
 23- 
 
 42 
 
 91 
 
 49 
 
 
 
 29 
 
 86 
 
 55 
 
 Do. yarn-room, - - - 
 
 16 
 
 42 
 
 
 57 
 
 
 
 29 
 
 101 
 
 72 
 
 Experiment 2d, (Art. 
 
 
 
 
 
 190.). 
 
 0.035466 
 
 60 
 
 190 
 
 130 
 
 Experiment 3d, (Ait. 
 
 
 
 
 
 190.). 
 
 0.070932 
 
 60 
 
 176 
 
 116 
 
 Ohservatioiu on the Table. 
 
 The 2d and 3d experiments only, are 
 inserted because the 2d shows xhs maximum 
 heat^ (An. 193,) and the 3d, the altera¬ 
 tion of temperature occasioned by heating 
 double the space by the same surface. 
 All the cases in the table have the surface, 
 either coated, or, what is equivalent, of 
 cast-iron, (Art. 142). 
 
230 
 
 HEATING BY STEAM. 
 
 SECTION IV. 
 
 195. Attempts have been made, to 
 bring a current of air over steam-pipes, 
 or through pipes included in others, filled 
 with steam, in order, by quickening the 
 condensation, to make a less surface of 
 steam-pipe heat an equal space. Mr. 
 Roberton tried this plan, by enclosing the 
 pipes in trunks, and producing a current, 
 by the rarefaction of the air *. I have at¬ 
 tempted the same thing, by increasing the 
 current of air by machinery, but I cannot 
 
 • These trials were made with pipes of tin-plate, included in 
 wooden trunks, at one end of the rooms. The air entered the trunk 
 at the floor, and escaped at the ceiling. Mr. Roberton found that the 
 heat was, to a certain degree, increased by this circulation, and that the 
 
 temperature, at the further end of a room of great extent, was nearly 
 
 equal to what it was near the tnmL From the pipes being made of 
 tin-plate, however, they required frequent repair, which rendered the 
 
 removed. Had it not been from this circumstance, he is of opinion, that 
 considerable advantage would have been derived from the trunks, and 
 would recommend them for cast-iron pipes, which would not require 
 
HEATING BY STEAM. 
 
 231 
 
 say, that much practical advantage has 
 resulted from these trials, (see Note C.) 
 We saw, however, (Art. 178.) that Mr. 
 Lee had successfully employed the prin¬ 
 ciple of rarefaction, in heating part of his 
 dwelling-house, and it is probable, that 
 this principle will be more generally ap¬ 
 plied. 
 
 It has been proposed by some, to heat 
 the external air, and throw it into the 
 apartments, in a manner similar to some 
 kinds of stoves, supposing, that thus by 
 combining ventilation with heatings it would 
 be more salubrious. But this would be 
 obtaining heat at a great expense of fuel, 
 and be losing one very important advan¬ 
 tage which attends heating by steam, 
 viz. that the heating may be kept perfectly 
 separate from the ventilating process, so 
 that each may be managed separately, and 
 no more heat nor ventilation given than 
 what is just proper. Whereas, on the 
 other plan, there must always be nearly 
 the same ventilation, whether the external 
 air be dry or damp, warm or cold. When 
 
232 HEATING BY STEAM. 
 
 damp, a great quantity of moisture must 
 be thrown into the building, which will 
 require additional heat to suspend it, in 
 order to prevent it from being injurious, 
 and when the air is dry, the current of 
 air will carry in dust along with it. I 
 would, therefore, recommend producing 
 the current from the rarefaction of the air 
 within the buildings and ventilating by the 
 window, or other proper openings for the 
 purpose. 
 
 Mr. Houldsworth found, that the maxi¬ 
 mum heat to be produced by the rarefac¬ 
 tion, was about 140 degrees. 
 
 196. Some have appi'ehended, that heating 
 by steam might be inconvenient, on ac- 
 cotmt of the very great heat which would be 
 felt for some feet round the pipes; but 
 this is not the fact, for even when they are 
 not included in any kind of air-trunk, as 
 soon as a particle of air becomes heated, 
 being specifically lighter, it has a tendency 
 to ascend to the ceiling of the apartment. 
 The warm air first accumulates there, and 
 
HEATING BY STEAM. 
 
 233 
 
 gradually descending, as is often visible 
 in a room, when warm air enters, mingled 
 with smoke. The cloud first appears 
 along the ceiling, and then gradually 
 descends, keeping nearly a uniform sur¬ 
 face below. 
 
 That no inconvenience arises in practice, 
 we have a full proof, in the case of an ex¬ 
 tensive cotton-mill in Manchester, (see 
 Art. 173.) which is 42 feet wide. The 
 steam-pipes go along the floor on one side 
 only., and although the yarn spun in this 
 mill be remarkably fine, no difference of 
 temperature is experienced, which, in the 
 smallest degree, affects that delicate pro¬ 
 cess. 
 
 197. V/hen speaking of spigot and faucet 
 joints, (Art. 154.) I omitted to mention, 
 that it seems a good method to cast the 
 faucets thin, and to hoop them with 
 slight wrought-iron, put on at a low red 
 heat. The thinness makes the faucets 
 expand along with the spigot, while the. 
 hoop gives strength, to allow the cement 
 to be firmly driven into the joint, 
 
 G g 
 
234 
 
 HEATING BY STEAM. 
 
 198. In Art 166, it is mentioned, that 
 a glass tube is sometimes used, to show the 
 height of the water in the boiler. This 
 simple contrivance, is, by some, applied for 
 the further very important purposes of 
 measuring the heat produced by the fuel 
 employed in a given time, and showing 
 the quantity of steam used. Great ad¬ 
 vantage may arise from ascertaining these 
 points. Thus, one kind of fuel may be 
 compared with another. Using the same 
 fuel, it will show the comparative effects 
 of different states of the furnace, and dif¬ 
 ferent modes of treatment. It also shows 
 accurately, the quantity of steam which a 
 steam-engine is using, according to the 
 order in which it is kept. It may, tliere- 
 fore, be proper to give a more detailed 
 explanation of the mode of using this 
 ingenious connivance. 
 
 The most simple and accurate mode of 
 comparing one kind of fuel with another, 
 is, to measure .the quantity of water which, 
 under the same circumstances, equal 
 weights of each will evaporate, (see Ar- 
 
HEATING BY STEAM. 
 
 235 
 
 tides 45, 52—70, and 111.) Now, by- 
 having a scale attached to die glass tube, 
 and knowing the dimensions of the boiler, 
 opposite each of the divisions on the scale, 
 it becomes easy to form a table, which 
 will readily show, the number of cubic 
 feet or inches, to which each division of 
 the scale is equal. 
 
 At the most convenient time of each 
 day, (which in many manufactories will 
 be the dinner hour,) put as much extra 
 water into the boiler, as will allow it to 
 boil for two hours, without getting any 
 supply of water whatever. This being 
 done, let every thing, excepting the feed¬ 
 ing apparatus of the boiler, be set to work 
 as usual for two hours. The scale will in¬ 
 dicate the cubic feet of water, which, dur¬ 
 ing that period, has been evaporated; a 
 register of which may be kept, from which 
 
 many useful practical inferences may be 
 
 drawn. 
 
 The tube should be a common bar- 
 rometer tube, of a pretty large bore, and 
 
HEATING BY STEAM. 
 
 the thinner it is, it will be the less liable 
 to break from unequal expansion. 
 
 199. Care should be taken, to have all 
 the pipes about the boiler sufficiently large, 
 to insure the prompt action of the feeding- 
 apparatus, and to prevent them from the 
 risk of choaking, by any extraneous matter 
 which may be in the boiler. 
 
 200. The pipes also, which are to 
 commimicate steam to a distance, should 
 be made sufficiently large, the sooner 
 to fill the more distant parts of the ap¬ 
 paratus. When the pipes are small, ffie 
 surface being great in proportion to the 
 contained steam, the condensation goes on 
 
 very rapidly, and retards die progress- of 
 
 the steam. 
 
 201. In situations where heat is not 
 wanted from the conducting pipes, it will 
 be proper to defend them from the atmos¬ 
 phere. This may be efficaciously done, 
 by enclosing them within tubes of tin¬ 
 plate, leaving a space all round, of about 
 
HEATING BY STEAM. 
 
 23*7 
 
 an inch between the steam-pipe and the 
 tin-tube, (see Articles 90—96, and 144). 
 
 But should this mode be thought too 
 expensive, a cheaper method may be 
 adopted, that of wrapping the steam-pipes 
 round with a considerable thickness of 
 straw ropes, putting a coating over them 
 of fine plaister-lime, and, after it is dry, 
 washing them over with lime-water, in 
 order to fill up any little cracks which 
 may appear. 
 
 202. Where there is found from experi¬ 
 ence, to he too much heat in one place of a 
 building, and too little in another, tin-tubes, 
 as above described, may be used, al¬ 
 lowing a current of air to pass between 
 them and the steam-pipes, which heated 
 air may be conveyed to any higher situa¬ 
 tion, by means of a pipe of tin-plate. 
 
 These covers may be made capable of 
 increase or diminution, by various contriv¬ 
 ances, such, for instance, as forming them 
 on the principles of a sliding spy-glass, as 
 
238 
 
 HEATING BY STEAM. 
 
 is done in the countmg-room of the priut- 
 ing-honse»of Messrs. James Ballantyne 
 &|Co. Edinburgh. 
 
 Brick-work, in some cases, may be used 
 for enclosing steam-pipes, instead of the 
 tin-plate. 
 
 203. A great saving of fuel may be ob¬ 
 tained, by using double sashes in the 
 windows, a practice common on some 
 parts of the Continent. 
 
 204:. We saw, (Art. 174 and 176.) that it 
 requires a considerable time, where there is 
 a great length of steam-pipes, to expel the air 
 from them, and to fill them with steam. To 
 obviate this inconvenience, Mr, H. Houlds- 
 worth proposed a plan, of applying a 
 pump to the pipes, worked by a steam- 
 engine. First, to expel the air, which 
 would allow the steam speedily to fill the 
 pipes. Afterwards, it would serve the 
 purpose of forcing back the water of con¬ 
 densation to the boiler, which would pro¬ 
 duce some saving of fuel; for it, at present. 
 
HEATING BY STEAM. 
 
 239 
 
 escapes nearly at the boiling-point, while 
 the boiler is supplied with water from the 
 air-pump of the steam-engine, about 100 
 degrees colder. Mr. Houldsworth’s plan 
 would be attended with a , further saving 
 of fuel, for, by the common mode, a uni¬ 
 form heat cannot be maintained, unless 
 there be a constant discharge of a small 
 quantity of steam from the extremity-of 
 the pipes, (Art. 168.) but the forcing-pump, 
 by occasioning a constant circulation of 
 steam in the pipes, would ensure a uni¬ 
 form heat, without any loss of steam. 
 This plan has not yet, however, been 
 brought to the test of experience. 
 
 205. The water of condensation^ being dis¬ 
 tilled water^ it may often be of use to col¬ 
 lect it for washing or other purposes, for 
 which soft pure water is desireable. 
 
 206. There is considerable difficulty in 
 obtaining accurate data, to compare the 
 eu!pense of fuel, in heating by steam with 
 other modes. From the best information, 
 however, that I could obtain, I made cal- 
 
HEATING BY STEAM. 
 
 culations on the supposition, that the 
 steam was supplied from a large boiler, 
 and the rest employed for driving a steam- 
 engine, or for some other useful purpose. 
 On this principle then, it appeared, in 
 general, that open fires require consider¬ 
 ably more fuel to heat the same space, than 
 steam. Stoves, as commonly constructed 
 
 and used in our cotton-mills, seem also to 
 require more fuel than steam. With regard 
 to the improved stoves, which are now 
 only beginning to be used in some manu¬ 
 factories, I do not know, that any accurate 
 comparison has yet been made. 
 
 207. In most manufactories, there is a 
 great many separate fires, which occasion, 
 in proportion to their number, not only a 
 loss of heat from the fuel consumed, but 
 also of waste from inattention and care¬ 
 lessness; where steam, therefore, can be 
 used as a substitute for these, a great 
 saving of fuel- will accrue. 
 
 208. Although in situations in which 
 there is a steam-engine, or a regular sup- 
 
HEATING BY STEAM. 241 
 
 ply of Steam kept up for other purposes, it 
 may be proper to use steam for warming 
 buildings; yet, where that is not the case, 
 unless a person can be appropriated to the 
 sole purpose of attending on the boiler, I 
 would hesitate to recommend it; for the 
 trouble and expense of attending on a 
 small boiler, on the common construction, 
 and risk from carelessness of not keeping 
 up a regular heat, or of having it burst or 
 burnt out, would more than counterbal¬ 
 ance the advantage otherwise to be derived 
 from it. But I am much pleased to find 
 that ingenious mechanics are turning their 
 attention to the fitting up of boilers, so as 
 to require less attendance *. 
 
 209. Steam, however, has many material 
 advantages over every kind of stoves; most 
 kinds of stoves are more or less liable to 
 injure the air, which comes in contact with 
 them, and to consume the dust. A dis¬ 
 agreeable oppressive smell is often pro¬ 
 duced, occasioned, probably, not only from 
 
242 HEATING BY STEAM. 
 
 the combustion of the dust, but also from 
 the decomposition of the water suspended 
 in the atmosphere. The disadvantages of 
 throwing in a current of air, by heating 
 the external air, and combining ventilation 
 with heating, have already been men¬ 
 tioned, (Art. 195,) and to these objections, 
 some of our most improved stoves are 
 liable. 
 
 All kinds of stoves are more or less 
 dangerous, and when constructed on the 
 principle of ventilation, they may become 
 particularly so, when the coakle or pan 
 cracks, or is burnt out. In that case, the 
 flames may find their way into the air- 
 flues, and so into the building. The 
 coakles, in many situations, soon fail in 
 some part; in which case, putting the 
 danger out of the question, they must 
 greatly contaminate the air. It has been 
 supposed, that more cotton-mills have been 
 destroyed by fire, occasioned by stoves, 
 than from all other causes put together. 
 
 But steam being free from dust, and 
 the atmosphere uninjured by its heat. 
 
HEATING BY STEAM. 
 
 while it is much more cleanly and safe, it 
 must be more healthful than any kind 
 of Stove. 
 
 Steam has another advantage over the 
 late improved stoves, that it can easily be 
 extended through buildings which are 
 widely spread, and nearly on the same 
 level; such, for instance, as are very com¬ 
 mon in calico printing works: whereas 
 from the tendency which heated air has to 
 ascend, it is exceedingly difficult to heat 
 places which are not considerably above 
 the level of the stove. 
 
 210. After considering the facts detailed 
 in this Essay, many other purposes than 
 those already mentioned, will suggest 
 themselves to readers, to which heating by 
 steam may be usefully applied. It would 
 require a greater scope of knowledge, than 
 an individual could lay claim to, to point 
 them out *. To some purposes, however, 
 
 • It is worthy the consideration of those acquainted with nautical 
 affairs, how far it may be applicable in ships, particularly in men of 
 
244 
 
 HEATING BY STEAM. 
 
 there may be considerable obstacles; for 
 instance, it has been often proposed for 
 heating hot-houses; but a difficulty occurs 
 here, of keeping up a regular heat during 
 the night, which could not, with a boiler 
 on the common construction, I believe, in 
 most cases, be done, without increasing the 
 expense of attendants. Were it not for 
 this objection, the heat from steam-pipes 
 appears to be more genial than that from 
 brick flues; and, in this case, perhaps a 
 boiler with a furnace similar to that de¬ 
 scribed in Mr. M'Naught’s letter, (Art. 
 180,) might be foimd to answer the pur¬ 
 pose, without any additional expense of 
 attendance. 
 
 But in the progress of improvement, 
 obstacles which at present exist to the use 
 of steam, may be removed. I have en¬ 
 deavoured plainly to state facts as they are 
 at present, and ingenious men may draw 
 conclusions from them, which may contri¬ 
 bute to extend the useful application of 
 steam to many purposes, to which it is not 
 at present thought applicable. 
 
HEATING BY STEAM. 
 
 245 
 
 NOTES. 
 
 Note A. 
 
 Messrs. H. Houldsworth & Co. at dieir 
 old mill, Anderston, have a boiler equal to 
 that commonly used for a steam-engine of 
 twenty-one horse’s power. 
 
 But their engine has only die power of 
 sixteen horses; there is, therefore, a sur¬ 
 plus power of five horses in the boiler, and 
 this is appropriated to the warming of the 
 building; for which purpose it is found 
 quite sufficient. 
 
 The building consists of the mill in 
 front, and a house behind, of the same 
 length as the mill; but not so large in its 
 other dimensions. 
 
 The mill contains 6 stories, each 116 
 feet long, by 27 feet 8 inches wide, by 9 
 feet high, equal to 28,884 cubic feet. 
 Therefore, 28,884 cubic feet multiplied by 
 6 stories, is equal to 173,304 cubic feet in 
 
246 HEATING BY STEAM, 
 
 the mill. The back house contains 76,696 
 cubic feet; the whole is, therefore, 250,000 
 cubic feet. Then will 250,000 cubic feet, 
 divided b^ five horses, be equal to 50,000 
 cubic feet, the space which a boiler of one 
 horse’s power will warm in a cottommill. 
 
 Now, reckoning that a horse’s power 
 occupies 25 cubic feet in a boiler, 50,000 
 cubic feet of space, divided by 25, is equal 
 to 2,000 cubic feet of space, which may be 
 warmed by 1 cubic foot of boiler. 
 
 It may be proper to observe, that this 
 allowance may be considered as perfectly 
 sufficient; for the thermometer in the mill 
 often stands above 80° of Fahrenheit. 
 
 In the Linwood cotton-mill, (see Note 
 B,) for every cubic foot of boiler, 2,500 
 cubic feet of space were warmed up to 70 
 degrees of Fahrenheit, under the disad¬ 
 vantages of a newly fitted up building, and 
 a lai'ge opening for the water-wheel. So 
 that we may safely reckon upon a horse's power 
 as being fully adequate to warm 50,000 cubic 
 
HEATING BY STEAM. 
 
 247 
 
 feet of space. Or., what amounts to the same 
 thing., that one cubic foot of boiler will warm 
 2,000 cubic feet of space. 
 
 Note B. 
 
 General ahslract relative to several Buildings 
 which have been warmed by Steam. 
 
 A j. u- .9 . 
 S K V 
 
 lllll 
 
 
 Cubic feet of 
 
 perficial foot 
 of steam pipe 
 
 
 ■warmed 
 >y 1 cubic 
 
 nil nil III 1 II 
 
 Cubic 
 feet in 
 boiler. 
 
 nsl hllMI 1 II 
 
 Cubic feet 
 
 building. 
 
 250,000 
 
 Substance of 
 which the 
 
 Cast-Iron, 
 
 Cast-Iron, 
 Cast-Iron, 
 Tin-Plate 
 not painted, 
 
 Cast-Iron. 
 
 Cast-Iron, 
 
 Cast-Iron, 
 
 Cast-Iron, 
 
 Cast-Iron, 
 
 Tin-Plate, 
 
 Tin-Plate, 
 
 Tin-Plate 
 
 painted, 
 
 Cast-Iron, 
 
 Name of Mills. 
 
 Messrs. H. Houldsworth & Co.'J 
 Anderston Old Mill, - J 
 Linwood Do. - - - - 
 
 Messrs.Kennedy &Watts, Johnston, 
 Catrine, ------ J 
 
 Mr.Thomas Houldsworth’s Mill, 7 
 Manchester, - - - - 5 
 
 Chapel of Port-Glasgow, - - 
 
 Part of AdelphI Cotton Works, 
 Tambouring Mill at Anderston, 
 Messrs. William King and Sons, 7 
 Johnston, ^ 
 
 Mr. Sym’s Mill, Glasgow, - - 
 
 Deanston Mill, Doun, - - - 
 
 Douglas, Cook, & Co.’s, - ^ 
 
 Messrs. Houldsworth & Hussie, 
 Inn at Johnston, ----- 
 
HEATING BY STEAM. 
 
 NoteC. (see Art. 195.) 
 
 In June 1806, I made the following 
 experiments, in order to try the effect on 
 the temperature of a room, by increasing 
 the current of air over the surface of steam- 
 pipes. 
 
 The room was 39 feet long, 22 feet 
 wide, and 9 feet high. It contained a group of 
 steam-pipes of tin-plate in a vertical posi¬ 
 tion, fitted up and enclosed in a wooden 
 trunk, upon Mr. Roberton’s plan, (Art. 
 195). In order to increase the current of 
 air, a pair of fanners were made to suck it 
 out of the upper part of the trunk, and to 
 throw it into the room. The fanners 
 were 18 inches diameter, and 12 inches 
 wide, making 600 revolutions per minute. 
 
 Bj^perhnent 1st. 
 
 External air - - - - 61“ 
 
 ' Heat of room from steam-pipes, fan¬ 
 ners at rest - - - - 71' 
 
 Fanners half an hour in motion raised 
 the temperature to - - 76’ 
 
HEATING BY STEAM. 
 
 249 
 
 After the .fanners had been 20 min¬ 
 utes at rest, the temperature fell to 73° 
 The fanners were put in motion again 
 for 15 minutes, which raised the 
 temperature to - - - 76° 
 
 Thermometer held in the stream of 
 air issuing from the fanners, rose 
 to.104° 
 
 Observatio7is. 
 
 The temperature of the room before the 
 steam was admitted into the pipes, was 
 omitted to be noted, but the difference 
 between the external temperature and that 
 of the room, was, at the beginning of the 
 experiment, 10°. The motion of the fan¬ 
 ners, increased the temperature 5° more. 
 
 Experiment 2rf. 
 
 F. Therm. 
 
 External air, - _ - - 63° 
 
 Heat of the room before admitting 
 the steam into the pipes, - 70 
 
 Steam in the pipes for an hour, but 
 the fanners at rest, raised the tem¬ 
 perature to - - - - 74° 
 
 I i 
 
250 HEATING BY STEAM. 
 
 Fanners in motion for half an hour, 
 raised the temperature to - 76° 
 
 Thermometer held in the stream of 
 air issuing from the fanners, rose 
 to - - ' - - - 125 
 
 Observations. 
 
 In experiment 2d, the temperature of 
 the room, previously to admitting the 
 steam into the pipes, was 7° higher than 
 the external air. The steam raised it in 
 an hour 4° more, and the fanners 2° 
 higher. 
 
 Hence the fanners appear to have in¬ 
 creased the efiect of the steam-pipes one- 
 half, but it must be confessed, that it 
 would require a more extensive and ac¬ 
 curate set of experiments, in order to draw 
 satisfactory inferences. In the mean time, 
 however, I hope the above facts may not 
 be without their value. 
 
251 
 
 ADDITIONS AND CORRECTIONS. 
 
 Art. 14—25. I find, that some of our 
 most eminent chemists, are not yet con¬ 
 vinced of the accuracy of Mr. Dalton’s 
 speculations, with regard to the law of the 
 expansion of liquids, and its influence on 
 the construction of the thermometer; nor 
 are they disposed to admit the alteration 
 in the thermometric scale, which Mr. 
 Dalton proposes. 
 
 Art. 58. Since this article was printed 
 ofi^, I have had an opportunity of reading 
 “ Speeches of H. Brougham, before the 
 committee of the House of Commons, in 
 opposition to the gas-light and coke com¬ 
 pany;” Mr. Brougham there states many- 
 curious and important facts, two of which 
 it will not be improper here to mention. 
 1st, TAat six pounds of coal produces light 
 equal to one pound of tallovo. 2d, That the 
 London Fire Company offered to insure 
 the works of Messrs. Philips & Lee, after 
 they were lighted by the coal gas, at one 
 half the former premium. 
 
252 ADDITIONS AND CORRECTIONS. 
 
 Art. 67. There has never, I believe, 
 been any very accurate comparison of Glas¬ 
 gow coal with that of Newcastle. Some 
 are of opinion, that it requires about double 
 the quantity of Glasgow coal to produce 
 the same heat as that of Newcastle. 
 
 Art 68. From the nature of the thing, 
 culm must differ much in its effects in 
 producing heat Therefore, we may ex¬ 
 pect some results very different from that 
 stated in this article. 
 
 Art. 154. It is a good method to make 
 the faucets with an inner part, no larger 
 in diameter than just to fit the spigot. This 
 supports the pipe, independently of the 
 cement, and prevents the risk of hurting 
 the joint from any external stress. This 
 iimer faucet is commonly made about two 
 inches deep, and has the spigot inserted 
 one inch into it. The practice of some, 
 is to make the outer faucet, or that which 
 contains the cement, six inches deep, for 
 all pipes above six inches diameter; and 
 to make the faucets of all pipes below six 
 
ADDITIONS AND CORRECTIONS. 253 
 
 inches, the same depth as the diameter of 
 the pipes. 
 
 It is usual to make the space for the 
 cement, all round the spigot, from i to t 
 an inch; that width is required, in order 
 that the cement may be firmly driven into 
 the joint. When the space is very nar¬ 
 row, this cannot be done. On the other 
 hand, when too wide, there is a waste of 
 cement, and a risk of injury from uneqyal 
 expansion. 
 
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