Buistmentarg anlJ lElementarg TREATISE ON STEAM AND LOCOMOTION . . liT JOHN SEWELI.. L.E. VOL. I. Price One Shiiling. LONDON: JOHN WEALE, riimm mmm THE UNIVERvSITY OT II T k . ar Hilbrai'T' Digitized by the Internet Archive in 2017 with funding from University of Illinois Urbana-Champaign Alternates https://archive.org/details/elementarytreati01sewe i 9 §k LOKD OF THE ISLES. ELEMENTARY TREATISE ox )••;,/ II I , STEAM AFD LOCOMOTION; BASED ON THE PRINCIPLE OF CONNECTINa SCIENCE WITH PEACTICE, IN A POPULAE POEM. SSlitS Ellustratt'cins. BY JOHN SEWELL, L.E. VOL. I. EonKon : JOHN WEALE, AECHITECTUEAL LIBEAEY, 69, HIGH HOLBOEN. MDCCCLII. :A- K .; ' ^ LONDON ; STEVENS AND CO., PRINTERS, BELL-YARD, TEMPLE-BAR. RaTlvray 27JaM0 *74” ■ 62 1.11 Se^e vl Hill '■ !■ 6;, The increasing extension of steam-power leads to an extend- V ing desire to become conversant with its economical produc- i- tion and employment. True economy is however slowly realised by practice alone, as is testified by the history of V*; many important inventions, as well as by that of the steam- rr, engine ; but when science and practice harmoniously co-ope- rate, progress is greatly accelerated. In steam locomotion it is an every-day duty to generate and employ steam ; but it requires the joint aid of both science and practice to de- cide whether these two distinct processes are or are not eco- nomically performed. In drawing inferences from observed ^facts, practice is powerfully assisted by a scientific know- ledge of the natural agents it has to deal with, and the properties of their compounds. In steam locomotion the na- >tural agents are water, fuel, heat, and metals. The com- pounds are combustion and steam. Science points out the composition of water, of fuel, and the heat-transmitting power of metals. It also acquaints us with the properties of steam, and the process of combustion. Practice observes facts corroborative or corrective of theories, and improves the mechanism, until, in the example of a locomotive engine, every pulsation of the escaping steam is evidence of the successful union of science and practice. The importance of such union, and the absence of early scientific education in a very large portion of the community, have led us to give a popular digest of the properties of water, fuel, heat and steam, with remarks on combustion and the manufacture of coke, as essential preliminaries to either true locomotion or even domestic economy. This digest is ac- companied by valuable classified tables of the mechanical, com- bustible, and chemical characteristics of 16S varieties of vi PREFACE. British and Foreign coals, derived principally from the im- portant researches conducted at the Museum of Practical Geology. This attempt to combine theory and practice is a plan strongly recommended by Sir H. De la Beche, Dr. Whewell, Dr. Lyon Playfair, and other eminent men of science, as necessary to progress ; also in the excellent philo- sophical work on Mathematical Physics, written by John Herepath, Esq. To promote such progress, and convey popular information on steam locomotion, is the design of this treatise, of which the first or theoretical part is now published. The second part, containing familiar descriptions of modern locomotive engines, will shortly follow. In a third part it is proposed to give a succinct historical outline of locomotive engines, with their connection with the eldest branch of the steam family noticed by Hero as ancient some 150 years before our era. It is intended to add to the third volume a copious index that shall be useful for reference to the great variety of subjects treated of in the work. To M. Morin, Director-General of the Conservatoire des Arts et Metiers, of Paris ; Daniel Gooch, Esq., C. E. ; Joseph Glynn, Esq., F. R. S. ; Goldsworthy Gurney, Esq. ; James Hann, Esq. ; J. Herepath, Esq. ; Seymour Clarke, Esq. ; John Gray, Esq., M.D. ; E. J, Dent, Esq. ; J. Hackworth, Esq. ; F. Trevethick, Esq. ; A. Torry, Esq. ; J. Deurance, Esq. ; W. Buckle, Esq. ; Hyde Clarke, Esq. ; and other prac- tical gentlemen who have placed information at the xluthor’s service, he begs to return his grateful thanks. There is much valuable knowledge floating amongst practical men, which would be useful if collected and arranged. Information, therefore, on any point connected with the history or improvement, either of past or modern locomotives, from any one, will be duly acknowledged, as contributions to an accurate history of steam locomotion, that honour may be given to whom honour is due. Dec. 1, 1851. JOHN SEWELL. CONTENTS. SECTION 1. CHAPTER I. PAGE STEAM . . . . . .1 Composition of water .... 2 Power of water . . . . .5 Table No. 1. — Comparative effect of motive powers . 8 Forcing power of water . . .8 Weight and measure of water ... 9 Table No. 2. — Weight of a gallon of water at various tempera- tures ..... 10 For cylindrical vessels or boilers . . ,11 Spherical vessels . . . . 11 Rectangular and cubical vessels . . ,12 Table No. 3. — Areas of the segments of a circle whose diameter is one, and divided into 1000 equal or 500 parts for each half of the circle . . . , 12 Problem, to find the area of a segment of a circle . . 14 Dimensions . . . . , 15 Summary . . , . , ,18 Steam space . . , . . 18 Water space . , . , ,19 Heating space , . , , 19 vm CONTENTS. PAGE Tabular Abstract of boiler contents . . .19 Abstract of tender contents • • . 20 Impurities of water . . . , .20 Table No. 4. — Impurities in one gallon of water . . 21 Hard and soft water for domestic use . . .24 CHAPTER II. HEAT . . . . . .27 Table No 5. — Linear expansion of solids at 212°, taking the length of the bar at 32° Fahr. as 1 foot . . 28 Table No, 6. — Averages of a few of the principal solids . 31 Table No. 7. — Expansion of fluids by the addition of 180° of heat, or at 212° taking the bulk or volume at 32° as 1 cubic foot ..... 31 Table No. 8. — Comparative expansion of water and air by heat. 32 Thermometers . . . . .32 Mercurial thermometers .... 33 Table No. 9. — ^Comparative temperatures of Fahr., De Lisle, Celsius, Reaum., from 600° Fahr., to freezing point of mer- cury . . , . .37 Table No. LO. — Effects of heat ... 42 Sources of heat . . . .44 Conduction ..... 45 Radiation . . . . .46 Convection . . . . . 49 Reflecting power . . . . .50 Specific heat . . , . . 50 Table No. 11. — Specific heat in different bodies . .51 Relative heat . . • • . 52 Combustion, or the production of heat . . .52 Combustibles and incombustibles ... 53 CONTENTS. IX Chemical combinations Mechanical mixtures .... Atmosphere .... Oxygen . . . Nitrogen ..... Carbon ..... Carbonic acid gas . . ^ . oxide ..... Hydrogen .... Comparative heat of carbon and hydrogen Heat from combustion Process of combustion in a furnace . Table No. 12. — Heat of combustion in the living furnace Application of heat to produce steam or evaporation Theories of heat .... Calorific theory of heat .... Latent heat .... Motion theory of heat .... Theory of heat as a fluid in motion Remarks on theories of heat Table No. 13. — Decrease of the measurable heat in air by diffu- sion ...... Table No. 14. — Increase of the measurable heat in air by concen- tration ..... Table No. 15. — Diffused heat of steam by different authorities . COKE ...... Table No. 16. — Ammoniacal products in coals Coke ovens ..... COALS ...... Evaporative value .... PAGE 54 54 54 55 56 57 58 59 59 60 60 61 66 66 68 69 70 70 71 72 77 77 78 81 82 89 97 98 Table No. 17 101 X CONTENTS. PAGE Table No. 18. — Specific and diffused heat of water and steam from 32" to 446° Fahr. .... 102 Table No. 19 ..... 103 Comparative evaporation of different boilers . .103 Coking quality of coals . . . .104 Table No. 20. — Comparative evaporation of water by coals and coke under the same conditions . . . 104 Mechanical structure . . . .106 Combustible character . . . .• 107 Chemical composition . . . .108 Table No. 21. — Products from destructive distillation of coals 109 Table No. 22. — Incombustible matters in coal ashes . . 109 Calorific value . . . . .109 Table No. 23. — Comparative cost and chemical properties of 37 varieties of Welsh coals . . . 110—111 Table No. 24. — Comparative cost and chemical characters of 19 varieties of the Newcastle district coals, and one sample of coke ..... 112—113 Table No. 25. — Comparative cost and chemical qualities “ 28 va- rieties of Lancashire coals . . . 114 — 115 Table No. 26. — Comparative cost and chemical properties of b va- rieties of Derbyshire, 8 of Scotch coals, 6 other varieties, and 6 varieties of patent fuel . . . 116 — 117 Table No. 27. — Summary of the mean averages of the coals from different localities . . . .118 Table No. 28. — Chemical composition of various foreign and co- lonial coals . . . . . 119 Table No. 29. — Chemical analysis of 42 varieties of American coals. Bituminous coals 120 122 CONTENTS. PAGE Anthracite . . . . .122 Evaporative value of the hydrogen in coals . . 124 Table No. 30. — Theoretical and practical duty of 1 lb. of coals, and its constituent parts . . . .125 Heating of the feed-water . . . 128 Table No. 31. — Ratio of the heat applied to feed-water to the total heat of steam of atmospheric pressure, or 1177*7° less the initial heat of the water, or say 52° temperature = 1125*70 . . . . .129 SECTION II. CHAPTER I. Varieties of Steam : Natural steam . . . . . . 130 Table No. 32. — Rate of natural evaporation of water . 132 Spheroidal steam . . . . .134 Heated steam or stame .... 135 Table No. 33. — Experiments on stame by the committee of the Arts and Sciences Institute, New York . .141 At low pressure . . . .141 At high pressure . . . . .141 CHAPTER II. Common steam . . . . . 142 ERRATUM. Page 103, Table 19, /or 7*000000 read 1*000000. LIST OF ILLTJSTEATIONS. Section of the Lord of the Isles . . . . Frontispiece Longitudinal section of a boiler ...... 16 Transverse section 16* Plan of fire-box 16 Elevation of tender tank . . . . .... 20 End view of ditto . . 20 Plan of ditto 20 Fahrenheit's thermometric scale ...... 34 De Lisle's ditto .......... 34 Centigrade .......... 34 Reaumer ........... 34 Violin-sound vibration .... ... 73 Bell-sound vibration ......... 73 Water boiling 74 Elevation of coke oven . . . . . . . .89 Section of ditto ......... 89 Plan of ditto 89 Elevation of Cox’s patent oven 90 Transverse section of ditto ........ 90 Longitudinal section of ditto ....... 90 Plan and section of coke cradle ..... .91 Ground plan of a set of coke ovens ...... 92 Plan of ditto at air passage ........ 93 Transverse section of ovens ....... 94 Longitudinal section of the oven at air-admission passages . . 94 Longitudinal section through chimney and flues ... 95 Section at junction with chimney ...... 95 Elevation . 95 Experimental glass tubes ........ 135 Expansion of steam in glass tube 135 Expansion of stame in ditto . . . , . . .135 Comparative scales of expansion 137 Expansion of water under mercury . .... 138 A TREATISE ON STEAM AND LOCOMOTION. SECTION I. CHAPTER I. STEAM. Steam is pure water expanded by beat into an invisible vapour. The first practical step is to obtain the water, and the next to apply the heat to produce steam power. That a power such as this is, which displays some of its force in ordinary domestic operations, should have arrested the at- tention of early philosophers to its capabilities is as natural a sequence of the new form given to water by heat, as that the steam from a tea-kettle should have pointed one of Dickens’s Christmas tales. Its employment in philosophical experi- ments, and also by the priests of early ages to maintain their ascendency over the minds of the people is matter of history, but the exact period of its first introduction appears to be un- known. The most ancient account of its performances now extant is a treatise published by Hero of Alexandria, about 150 years before our era, or nearly 2000 years ago. In this treatise he described amongst the inventions of others, some of his own (which will be described in their place), and these have gained him the honour of being regarded as the first inventor of the steam engine, and Egypt as the land of its origin. 2 COMPOSITION OF WATER. To understand the nature of steam, it is desirable to possess a knowledge of its component parts. Familiar as are these component bodies, water and heat, yet each of them has formed the subject of elaborate researches, and each of them yet excites interest ; the water, as to its composition, and the heat as to its nature. Taking them in their order of forming steam, the following summary of the generally received opinions regarding them will, it is trusted, prove interesting. Composition of Water, This well-known fluid is the basis of the weight and ma- teriality of steam. In its ordinary state water is a fluid covering a very large portion of the globe, performing most important duties. It is not only abundant as a fluid, but, united with other bodies, it forms a large proportion of animal and vegetable matter, for analyists tell us that potatoes contain 75 per cent., turnips 90 per cent., a beef steak 80 per cent., and a man 75 per cent, of water. Chemically, they tell us that, a man of 10 stone would be made up of 105 lbs. of water, and 35 lbs. of carbon and nitrogen, and that |ths of his daily food is water. It has been general since Watt’s discovery of the composi- tion of water to define it as consisting of one volume of oxygen and two volumes of hydrogen, or by weight, 1 part of hydro- gen and 8 parts of oxygen, the specific gravity of the latter being 16 times that of the former. It is usual to prove this theory of the composition of water by burning or exploding these two gases in a glass vessel, when water is deposited equal in weight to that of the decom- posed gases. It has, however, been suggested that the force required to compress these gases into water must also find some electrical agent in them so as to produce their marked compression in volume. For water is nearly 30 times heavier DECOMPOSITION OF WATER. than oxygen, 478 times heavier than hydrogen, and 34 times heavier than air. The discovery of the composition of water has been ascrib- ed by some to Watt, and by others to Cavendish. Lord Brougham, in his Discourse on Natural Theology, states, “Hav- ing examined the evidence, I am convinced Watt was the first discoverer in point ot* time.’^ This being regarded as one of the greatest discoveries of the age, was naturally a point of emulation amongst those having the least chance of gaining such honour, and it has by no mean authority been awarded to Watt. Science, however, both in x\m erica and in Belgium, has again aroused attention to the decomposition of water, and to the various economical uses to whichit may be applied. About twenty years ago, Macvicar, of St. Andrews, called attention to the particles, or atoms, constituting hydrogen as being of the simplest forms, and that water might either be all hydrogen, or partly oxygen, partly hydrogen, as the atoms were in a more or less divided state. He regarded the hydro- gen atom as the elementary one, and that electrical affinity combined these atoms in a variety of ways, to form oxygen, water, or other substances. These views received little notice at the time, but they are now apparently confirmed by the reported discoveries of Mr. Payne, of America. These discoveries, if fairly established, are of great import- ance, and merit a short description of this mode of decompos- ing water to obtain heat, light, and power. According to Mr. Payne’s experiments, water can be con- verted into hydrogen, or oxygen, without any appearance of the other gas, or both gases can be produced at once. This is effected by a magneto-electric machine, with two horse- shoe magnets, about 12 inches long, placed horizontally on a frame, but the one 4 inches higher than the other. Between the ends of these magnets, two helices are set in rapid motion by a wheel. In the construction of the helices the greatly in- B 2 4 DECOMPOSITION OF WATER. creased power is said to be obtained. They are not formed of solid wire, as is usual, but of copper strips wound round spirally so as to form a hollow wire in which water can be confined. This wire is insulated by means of India rubber or gutta percha. Faraday has demonstrated that a small quantity of water will contain a vast quantity of electricity, so that it is inferred that as the water power of the helices is in- creased to induce or receive the electric current, so is the power increased to give it off. The manner of applying the power so obtained is as fol- lows : — In an open vessel of water is placed a common bell glass, reaching within 4 inches of the bottom of the vessel. The top of this glass is fitted with a brass cap for admitting the wires for connecting it with another jar of spirit of tur- pentine, when it is required for illumination. After passing through this cap of the first jar, the wires terminate in a cylin- drical box inches long by 1 inch diameter, perforated with small holes round the top part. In this box are the electrodes or points of connection of the poles, and here is the point of danger from the intensity of the force evolved by the helices. The turpentine jar has also a cap fitted to it for connecting it with the water jar, and also with a gas burner. It is stated that hydrogen only is produced by the action of the negative electricity, and oxygen only by positive electricity ; but when both kinds of electricity are used, both oxygen and hydrogen are evolved. The interruption of the alternate cur- rent is said to be effected by immersing the broken ends of the wire in a glass of water, without being in contact, leaving the broken wire less active. For illumination the hydrogen is passed through the turpentine, when it becomes catalized,” and burns with great brilliancy. From this it is inferred that hydrogen is a gas and negative electricity, and oxygen the same gas and positive electricity, and that water is, therefore, either all hydrogen, or all oxygen, or partly both, according to the electricity employed in decom- POWER OF FREEZING WATER. O posing it. The cost of production is said to be so small that either as a power or as a combustible it will exercise great economical influence. The editor of the Boston Chronotype/’ who appears to have seen the whole process gone through, states, “ The power of the helices to the mechanical combination of the machine, is comparatively as the force of water in moving a large water wheel is to the force required to raise the water gate.’’ He also distinctly warns experimenters to be guarded as to the power evolved in the electrode, lest it should prove uncontrollable with serious results, for each discharge of the helices produces a numerous crop of bubbles of gas in the water. These bubbles are a singular and important coinci- dence with the globules formed by ordinary heat in generating steam, which will be further noticed under that head. Trials by our own electricians are said to have failed, yet M. Nollet, of Brussels, has just patented in England his improved plan and the use of the gases 'as a motive power similar to steam in the atmospheric engine. ^ower of Water. Simple as may be the appearance of water, it forms a most valuable part of creatiom and in each of its characters, of a solid, as ice ; of a fluid,'^as water ; or of a vapour, as steam, it developes immense power. It is at its greatest density about 40° Fah. but does not become solid until 32^, when its expan- sive force is exhibited in the disintegration of rocks, bursting of pipes, or fracturing other bodies in which it may be confined, as practically tested in the following trials made in the Arsenal at Warsaw, in 1828-9, for the purpose of ascertaining the ex- pansive force of water in a state of freezing. For this purpose cast-iron howitzer shells. Gin. 8 lines diame- ter, having a thickness of metal 1 in. 2 lines, and an orifice, or opening of 1 in. 2 lines diameter, were employed. One of these 6 MOTIVE POWER OF WATER. shells having a capacity of 46*29 cubic in. was filled with water at 40° Fah. and with the orifice open exposed to the atmosphere at 21° Fah. In two hours a column of ice 2 in. 2 lines long was projected from the opening, which was the greatest effort made, and gave an expansive force of 2*31 cub. in. or about ^th part of the whole volume, or 5 per cent. A second shell was filled, and the orifice closed with a piece of wood driven into it. It was then exposed as before, when the plug was expelled, and ice occupied its place. A third shell was filled, and the orifice closed with an iron screw, having through it a hole 3 lines diameter. After two hours’ exposure the shell was burst into two unequal parts, the smaller being thrown 10 feet, and the larger part thrown 1 foot from the spot it was placed upon. The ice had formed only 6 lines thick, the remainder being still fluid. A fourth shell was filled, plugged, and exposed at 28° in a similar man- ner, with a hole of 6 lines diameter, and also burst in two parts, one of them being thrown a distance of 4 feet. The ice was 1 3 lines thick, the rest fluid. A fifth shell was filled, plugged up solidly, and exposed at 28°, when it burst as before, and the smallest piece was thrown a distance of one foot. The thickness of the ice was only 5 lines. These will convey some definite idea of the expansive power of water in a freezing state, which is supposed to be derived from the re-arrangement of the crystalizing particles in angles of 60° or 120° to each other, requiring more space than when in a fluid state, and thus resisting confinement. In giving motion to machinery, water, from its uniform action, has long been held in deserved repute. It has been at- tempted to be made the means of keeping up a regular power by a given quantity of water raised by a steam engine, and then giving motion to an overshot water wheel. The following table will show that the best constructed water wheels yet used do not exceed 80 per cent, of the full weight of water, consequently to employ steam power to raise another power. POWER OF WATER WHEELS. 7 and then to lose 20 per cent, of the power so raised was the reverse of economy, and has, of course, been abandoned. Of the water employed on the different wheels the useful effect is for The Undershot Wheel from 27 to 33 per cent. ,, Breast ,, ,, 45 „ 52 >> ,, Overshot ,, ,, 60 „ 80 39 „ Re-action or Turbine 56 „ 78 33 It may be explained that the undershot wheel is used when a fall is not obtainable, and the water only acts by its force against the float at the extremity of the arms. The breast wheel is employed where there is more fall, and the water en- ters the buckets, and acts by its weight. The overshot wheel is general where there is sufficient fall to carry the water over its top, and allow it to act on the opposite side, both by its force and weight. The turbine is of modern invention, where the water enters the arms of the wheel from a central tube, and issues by orifices at their extremities, but on opposite sides. The force of the issuing water being thus unbalanced, or flowing in one direction only, causes the arms to revolve in contrary directions. As now improved both in this country and on the Continent, these wheels are in considerable repute for economy of power and space. Gwyne’s newly patented modification of the turbine and bucket wheel is said to gene- rate 85 per cent, of the power employed. In all these wheels the weight of water is as its contents multiplied by its gravity of 10 lbs. each imperial gallon, but its force or pressure is as its height. Thus comparatively a column of water 34 ft. high, a column of air the entire height of the atmosphere, and a column of mercury 30 in. high are all equal in weight. That weight is nearly 14| lbs. avoirdupois. The following table, by Fenwick, of the power of an overshot water wheel, a wind mill, and a steam engine, will be useful for reference ; — 8 FORCING POWER OF WATER Table No. ] . COMPARATIVE EFFECT OF MOTIVE POWERS. WATER, acting on a 10-foot wheel, per min. STEAM. Diameter of Cylinder. HORSES, each 12 hours, at a rate of 2 miles per hour. MEN, each 12 hours per day. WIND. Radius of Sails. POWER, = 1000 lbs. raised per minute. Old Class. Improved Class. Common. Dutch. Smeaton’s. Lbs. Inch. Inch. No. No. Feet. Feet. Feet. Feet. 2,300 8 6-12 1 5 21-24 17-89 15*65 13 3,900 9-5 7*8 2 10 30-04 25*30 22-13 26 5,280 10*5 8-2 3 15 36-80 30-98 27-11 39 6,600 11-5 8-8 4 20 42-48 35*78 31*3 52 7,900 12-5 9-35 5 25 47-50 40 * 35 - 65 9,700 14 * 10*55 6 30 52-03 43-82 38-34 78 11,700 15*4 11-75 7 35 56-90 47-33 41-41 91 13,500 16-8 12-8 8 40 60*09 50-60 44*27 104 14,550 17-3 13-6 9 45 63*73 53*66 46*96 117 15,840 18*5 14-2 10 5(1 67*17 56*57 49-50 130 17,400 19*4 14-8 11 55 70*46 59*33 51-91 143 19,000 20*2 15-2 12 60 73*59 61*97 54-22 156 21,000 21 - 16-2 13 65 76*59 64*5 56-43 169 23,000 22 - 17 - 14 70 79-49 66-94 58-57 182 25,000 23-1 17-8 15 75 82*27 69*28 60*62 195 26,860 23-9 18-3 16 80 84-97 71-55 62*61 208 28,700 24-7 19 - 17 85 87'07 73*32 64*16 221 30,550 25-5 19-6 18 90 90*13 75-90 67*41 234 32,400 26-2 20*1 19 95 92-60 77-98 68-23 247 34,260 27 - 20-7 20 100 95 - 80 * 70 * 260 37,500 28-5 22*2 22 no 99*64 83*9 73-42 286 40,000 29-8 23 - 24 120 104*06 87-63 75*68 312 44,600 3 M 23-9 26 130 108-32 91*22 79*81 338 48,500 32-4 24-7 28 140 112*20 94-66 82*82 364 52,500 33*6 25-5 30 150 116-35 97-98 85-73 390 Forcing Poiver of Water, Water forms a remarkable exception to the general law of expansion by heat, for it is more bulky when only 32° than when it is 8° hotter, or 40° temperature. Being then at its greatest density, and almost incompressible, it is made to develop its immense power in Bramah’s hydraulic presses, whereby the strength of cables, anchors, iron, and other materials is tested, goods packed, and other operations per- formed requiring great force. WEIGHT AND MEASURE OF WATER. 9 One of its most recent performances in this field was lifting the Conway and Britannia tubular bridges, up 100 ft. into their places. The weight of the largest tube being about 1800 tons, and one end lifted at a time, gave about 900 tons as the weight to be raised at once. This was done by a strong cast-iron cylinder, 11 in. thick, with a solid piston, or ram 20 in. in diameter and 6 ft. stroke, working through a water-tight stuffing box or gland, now to be seen in the Industrial Exhibition. Into this cylinder the water was forced through a half-inch pipe by a pump of lyV in. diameter worked by a 40-horse steam engine. The power would therefore be as the areas of the ram and pump were to each other, or as 1 to 355. The pressure on the ram would then be 900 tons, or 900 X 2240 (lbs. water) ^ . , - „ ^ r " -- 7 . - T — ( = 6417 lbs. pressure for 314*16 (area ot piston) each square inch of the head of the ram.* The action may be thus explained : water is slowly forced into the cylinder by the pump, and being very nearly incompressible, as soon as the vacant space in the cylinder is filled, it gradually impels the ram outwards, with a force measured by the resistance against the external end of the ram, and limited by the strength of the cylinder and power of the pump to force in the water. Weight and Measure of Water, ^ ‘ “ As a liquid, water is made the standard of comparison of the specific weight or gravities of other liquids and solids. At 55° fah. a cubic foot of water weighs 998*74 ounces avoidupois, but for facility in calculations it is generally taken as 1000 ounces, and the imperial gallon is fixed at 160 ounces, or 10 lbs. avoirdupois of distilled water. By weight a cubic foot of water is taken as 62^ lbs., and by this data the cubic contents in feet of any water tank or boiler multiplied by 62^ gives the weight of water in lbs. avoirdupois, and these * For an interesting description of these bridges, see Rudimentary Treatise on Iron Girder Bridges. B 3 10 WEIGHT AND MEASURE OF WATER lbs. divided by 10 give tbe number of gallons. Thus if the • water space in a boiler be 60 cubic ft. it will contain 3750 lbs. or 375 gallons of water, for 60 X 62-5 = 3750 lbs. and = 375 gallons. The standard fixed by Parliament for the Imperial gallon being 10 lbs. avoirdupois, at a temperature of 62 Fah, the following table gives the weight of a gallon of water at each degree of temperature from 32*^ to 80^ : Table No. 2. WEIGHT OF A GALLON OF WATER AT VARIOUS TEMPERATURES. Deg. Fah. Lbs. Avoir. Deg. Fah. Lbs. Avoir. Deg. Fah. Lbs. Avoir. 80 9*9777 63 9-9989 47 10*0099 79 9*9792 62 10*0000 46 10*0102 78 9*9806 61 10*0010 45 10*0105 77 9*9820 60 10*0019' 44 10*0107 76 9*9834 59 10*0027 43 10*0109 75 9*9848 58 10*0035 42 10*0111 74 9*9861 57 10*0043 41 10*0112 73 9*9874 56 10*0050 40 10*0113 72 9*9887 55 10*0057 39 10*0113 71 9*9900 54 10*0064 38 10*0113 70 9*9912 53 10*0070 37 10*0112 69 9*9924 52 10*0076 36 10*0111 68 9*9935 51 10*0082 35 10*0109 67 9*9946 50 10 0087 34 10*0107 66 9*9957 49 10*0091 33 10*0104 65 64 9*9968 9*9979 48 10*0095 32 10*0101 This shows that from the point of greatest density (38° to 40°) it expands equally in both ways, becoming gradually 4 IN VARIOUS VESSELS. 11 lighter per gallon. Sea water has its greatest density at the freezing point. For calculating the quantities of water contained in either cylindrical or rectangular vessels, the following approximate exponents of the relative weights and measures of water at its ordinary temperature will be useful. Fo 7^ Cylmd^^ical Vessels or Boilers, Water, Cyl. in. 1 or 12 or 1728 or 2*282 cyl. ft. 45'64 cyl. ft. Diam. length. Lbs. avr. Imp. gal. 1 X 1 = *02842 or *00284 1 xl2= *341 or *034 1 cyl. ft. =49*1 or 4*91 = 1 cwt. or 11*2 = 1 ton or 224* 352*97 cyl. in. = 1 gal. 1*273 ,, = 1 cubic in. 1* „ = *7854 To find the capacity of any other cylinder, multiply the square of its diameter by its length, and the product by the exponent of the unit of the feet or inches in which the dimen- sions may be taken. For elliptical vessels or boilers multiply the longest by the shortest diameter, and by the length for the capacity in cylindrical inches, and the product by the re- quired exponent. For concentric spaces add together the inner and outer di- ameters, and multiply the sum by the difference of these diameters, and by the length for the capacity in cylindrical inches, which being multiplied by the tabular exponent will give the required quantity. Spherical Vessels, lbs. avr. gal. imp. A globe of water 1 in. diam. = *0189 or *001888 or 1 spherical inch. A globe of water 12 in. diam. = 32*75 or 3*263 ©r 1 spherical foot. To find the capacity of any other sphere multiply the cube of its diameter by the required exponent of unity of the di- mensions taken in feet or inches. 12 AREAS OF SEGMENTS Uectangular and Cubical Vessels. Water. Cub. in. Sq. length. Lbs. avr. Imp. gal. 1 or 1x1= '03617 or •00361 12 or 1 X 12 = *434 or •0434 1728 or 1 cub. ft. = 62*5 or 6*25 1'8 cub. ft. = 1 cwt. or 11*2 35*84 ,, = 1 ton or 277*274cub.in. = 1 imp. gal. 224* *1 „ = 1*273 cyl. in. *7854 „ = 1* The cubical contents of any other rectangular vessel may found by multiplying the length, width and depth together, and their product by the requisite exponent. Table No. 3. AREAS OF THE SEGMENTS OF A CIRCLE, Whose diameter is one, and divided into 1000 equal or 500 parts for each half of the circle. Hgbt Area Seg. Hght Area Seg. Hght Area Seg. Hght Area Seg. Hght Area Seg. *001 •000042 •022 •014322 •043 •011734 •064 *021168 •085 •032186 •002 000119 •023 •004618 •044 •012142 •065 *021659 •086 *032745 *003 .000219 •024 •004921 •045 •012554 •066 •022154 •087 •033307 *004 *000337 •025 •005230 •046 •012971 •067 •022652 •088 *033872 *005 •000470 •026 •005546 •047 •013392 •068 •023154 •089 *034441 *006 •000618 •027 .005867 •048 •013818 •069 *023659 •090 •035011 •007 •000779 •028 •006194 •049 •014247 •070 •024168 •091 •035585 •008 •000951 •029 *006527 •050 •014681 •071 *024680 •092 •036162 *009 •001135 •030 •006865 •051 •015119 •072 •025195 •093 •036741 *010 *001329 •031 •007209 •052 •015561 •073 •025714 *094 •037323 •oil •001533 •032 •007558 •053 •016007 •074 *026236 •095 •037909 •012 •001746 •033 •007913 *054 *016457 •075 *026761 •096 *038496 •013 •001968 •034 •008273 *055 •016911 •076 •027289 .097 •039087 •014 •002199 •035 •008638 056 •017369 •077 *027821 ^098 •039680 *015 •002438 •036 •009008 •057 *017831 •078 •028356 •099 •040276 •016 •002685 •037 •009383 •058 •018296 •079 •028894 •100 •040875 •017 •002940 •038 •009763 •059 •018766 •080 •029435 *101 •041476 •018 •003202 •039 •010148 •060 •019239 •081 •029979 •102 •042080 •019 *003471 •040 •010537 •061 •019716 •082 •030526 •103 •042687 *020 •003748 •041 •010931 •062 •020196 •083 *031076 •104 •043296 *021 *004031 •042 •011330 •063 •020680 •084 *031629 •105 *043908 AREAS OF SEGMENTS. 13 light Area Scg. light Area Seg. light Area Seg. light Area Seg. light Area Scg. •100 •044522 •154 ■070746 •202 •113426 •250 •153546 •298 196337 •107 •045139 •155 •077469 •203 •114230 •251 •154412 •299 197252 •108 •045759 •156 •078194 •204 •115035 •252 •155280 •300 198168 •109 •046381 •157 •078921 •205 •115842 •253 •156149 •301 199085 •no •047005 •158 •079649 •206 •116650 •254 •157019 •302 200003 •111 •047632 •159 •080380 •207 •117460 •255 •157890 •303 200922 •112 •048262 •160 •081112 •208 •118271 •256 •158762 •304 201841 •113 •048894 •161 ■081846 •209 •110083 •257 •159636 •305 202761 •114 •049528 •162 •082582 •210 •119897 •258 •160510 •306 203683 •115 •050165 •163 •083320 •211 •120712 •259 •161386 •307 204605 •116 •040804 •164 •084059 •212 •121529 •260 •162263 •308 •205527 •117 • 05144 G •165 •084801 213 •122347 •261 •163140 •309 •206451 •118 •052090 •166 •085544 •214 •123167 •262 •164019 •310 •207376 •119 •052736 •167 •086289 •215 •123988 •263 •164899 •311 •208301 •120 •053385 •168 •087036 •216 •124810 •264 •165780 •312 •209227 •121 •054036 •169 •087785 •217 •125634 •265 •166663 •313 •210154 •122 •054689 •170 •088535 •218 •126459 •266 •167546 •314 •211082 •123 •055345 •171 •089287 •219 •127285 •267 •168430 •315 •212011 •124 •056003 •]72 •090041 •220 •128113 •268 •169315 •316 •212940 •125 •056663 •173 •090797 221 •128942 •269 •170202 •317 •213871 •126 •057326 •174 •091554 •222 •129773 •270 •171089 •318 •214802 •127 •057991 •175 •092313 •223 •130605 •271 •171971 •319 •215733 •128 •058658 •176 •093074 •224 •131438 •272 •172867 •320 •216666 •129 •059327 •177 •093836 •225 •132272 •273 •173758 • 32 i •217599 •130 •059999 •178 •094601 •226 •133108 •274 '174649 •322 •218533 •131 •060672 •179 •095366 •227 •133945 •275 •175542 •323 •219468 •132 •061348 •180 •096134 •228 •134784 •276 •176435 •324 •220404 •133 •062026 •181 •096903 •229 •135624 •277 •177330 •325 •221340 •134 •062707 •182 •097674 •230 •136465 •278 •178225 •326 •222277 •135 •063389 •183 •098447 •231 •137307 •279 •179122 •327 •223215 •136 •064074 •184 •099221 •232 •138150 •280 •180019 •328 •224154 •137 •064760 •185 •099997 •233 •138995 •281 •180918 •329 •225093 •138 •065449 •186 •100774 •234 •139841 •282 •181817 •330 •226033 •139 066140 •187 •101553 •235 .140688 •283 •182718 •331 •226974 •140 •066833 •188 •102334 •236 •141537 •284 •183619 •332 •227915 •141 •067528 •189 •103116 •237 •142387 •285 •184521 •333 •228858 •142 ■068225 •190 •103900 •238 •143238 •286 •185425 •334 ■229801 •143 •068924 •191 •104685 •239 •144091 •287 •186329 •335 •230745 •144 •069625 •192 •105472 •240 •144944 •288 •187234 •336 •231689 •145 •070328 •193 •106261 •241 •145799 •289 •188140 •337 •232634 •146 •071033 •194 •107051 •242 •146655 •290 • 1894)47 •338 •233580 •147 •071741 •195 •107842 •243 •147512 •291 •189955 •339 •234526 •148 •072450 •196 •108636 •244 •148371 •292 •190864 •340 •235473 •149 •073161 •197 •109430 •245 •149230 •293 •191775 '341 •236421 •150 ' -073874 •198 •110226 •246 •150091 •294 192684 •342 •237369 •151 •074589 •199 •111024 •247 •150953 •295 •193596 •343 •238318 •152 •075306 •200 •111823 •248 •151816 •296 •194509 •344 •239268 •153 > -076026 •201 •112624 •249 •152680 •297 •195422 •345 240218 14 AREAS OF SEGMENTS. light Area Seg. light Area Seg. Hght Area Seg. Hght Area Seg. Hght Area Seg. •346 *241169 :-377 •270951 •408 •301220 •439 •331850 •470 •362717 •347 -242121 i-378 •271920 •409 •302203 •440 •332843 •471 •363715 •348 -243074 •379 •272890 •410 •303187 •441 •333836 •472 •364713 •349 -244026 j 380 •273861 •411 •304171 •442 •334829 •473 •365712 •350 -244980 •381 •274832 •412 •305155 •443 •335822 •474 •366710 •351 -245934 •382 •275803 •413 •306140 •444 •336816 •475 ■367709 •352 -246889 1-383 •276775 •414 •307125 •445 •337810 •476 •368708 •353 -247845 1-384 •277748 •415 •308110 •446 •338804 •477 •369707 •354 -248801 •385 •278721 •416 •309095 •447 •339798 •478 •370706 •355 -249757 •386 •279694 •417 •310081 •448 •340793 •479 •371704 •356 -250715 •387 •280668 •418 •311068 •449 •341787 •480 •372704 •357 -251673 •388 •281642 •419 •312054 •450 •342782 •481 •373703 •358 -252631 •389 •282617 •420 •313041 •451 •343777 •482 •374702 •359 -253590 •390 •283592 •421 •314029 •452 •344772 •483 •375702 •360 -254550 •391 •284568 •422 •315016 •453 •345768 •484 •376702 •361 -255510 •392 •285544 •423 •316004 •454 •346764 •485 •377701 •362-256471 ‘393 •286521 •424 •316992 •455 •347759 •486 •378701 •363 -257433 •394 •287498 •425 •317981 •456 •348755 •487 •379700 •364 -258395 •395 •288476 •426 •318970 •457 •349752 •488 •380700 •365 -259357 •396 •289453 •427 •319959 •458 •350748 •489 •381699 •366 -260320 •397 •290432 •428 •320948 •459 •351745 •490 •382699 •367 -261284 •398 •291411 •429 •321938 •460 •352742 •491 ; •383699 •368 -262248 •399 •292390 •430 •322928 •461 •353739 •492 •384699 •369 -263213 •400 •293369 •431 •323918 •462 •354736 •493' •385699 •370 -264178 •401 •294349 •432 •324909 •463 •355732 '494 •386699 •371 -265144 •402 •295330 ‘433 •325900 •464 •356730 •495 •387699 •372 -266111 •403 •296311 •434 •326892 •465 •357727 •496 •388699 •373 -267078 •404 •297292 •435 •327882 •466 •358725 •497 •389699 :-374 -268045 •405 •298273 •436 •328874 •467 •359723 •498 •390699 i-375 -269013 •406 •299255 •437 •329866 •468 •360721 .499 .391699 •376 -269982 •407 •300238 •438 •330858 •469 •361719 .500 •392699 PROBLEM, To find the Area of a Segment of a Circle, IluLE. — Divide the height, or versed sine, by the diameter of the circle, opposite the quotient in the column of heights. Take out the area, in the column on the right hand, and multiply it by the square of the diameter, for the area of the segment. Example, — Required the area of a segment of a circle, WATER, FIRE, AND STEAM SPACES IN A BOILER. 15 whose height is 9 inches, and the diameter of the circle 58 inches. 9-^58 = *155 and opposite *155 = *07747 x 58^= 261*5 sq. in. X 1*273 = 331 cubic inches, as the required area. In calculating the separate contents of a cylindrical boiler, segmental spaces require to be measured, and for this purpose the foregoing tabular area of 500 segments or one half of a circle whose diameter is 1, or unity, will be useful. The areas are in square measure, which requires to be multiplied by 1*273 for circular inches. The following practical examples will show how part of these exponents may be usefully applied to ascertain very nearly the quantity of water which is in any boiler or tender, or other vessel. Example 1. — Taking the dimensions of the Lord of the Isles’ locomotive boiler to be as under, required the quantity of water in tons and in gallons which would fill it to the waterline 9 inches below the top of the cylindrical part of the boiler. Dimensions, Cylindrical part, 1 1 ft. long by 58 in. diameter, con- taining 303 tubes, each 2 in. external diameter, and 10 iron stay rods each 1| in. diameter. Steam space a segment of the top of this part whose height or versed sine is 9 in. Fire Box part, 71m. wide, 66 in. long, and 63 in, mean depth, less inside fire box, 64 ,, 60 ,, ,, 63 ,, ,, leaving water spaces. Front and back 71 in. wide, 63 in. deep, and 3 in. mean space. Two sides, each 60 in. long, .63 in. ,, and 3^ in. ,, ,, Top of fire box 69 in. wide, 9 in. ,, and 66 in. long. Partition 63 in. ,, 51 in. ,, and 4 in. space. Less. // // // ^i^* 1^' Fire door 21 x 18 x 3 tubes = 1212 x 3, in. long. 12 stays 1^ x 6^ x 60, 10 stay rods 1:^ diam. x 66 in. long. 16 WATER, FIRE, AND STEAM SPACES Steam space, a segment of the top of the fire hox whose height or versed sine is 15 inches of a circle 71 inches diameter. Boiler. Longitudinal Section. These three diagrams will give an outline of the internal arrangement of the water, fire, and steam spaces in the Lord of the Isles’ locomotive boiler. Fig. No. 1 is a longitudinal section, showing the front and back water spaces between the outside shell of the boiler and inside fire-box. The transverse central water space which reaches up to the level of the fire door in the centre, and higher at the sides is also shown. The fire-box is thus divided IN A LOCOMOTIVE I30ILER. 17 into two rectangular spaces, whose flat sides are strongly- secured by numerous copper stays to the outside shell to resist the force of the steam. From the smallness of the diagrams these stays are not shown, but only one of the strong wrought- iron stays necessary to support the flat top of the fire-box, 303 tubes each, 1 1 ft. long, by 2 inches external diameter convey the heated gases from the fire to the chimney, usually placed on the top of the smoke box. The line of the water level shows the comparative depth of the sectional steam and water spaces, whilst the line of the tubes and top of the fire- box shows the heating space. Fig. No. 2 is a transverse sectional view of the fire-box, showing the two side water spaces between the inside and out- side boxes, which are also strongly secured together by copper stays. The complete circle shows the area of the cylindrical part of the boiler, and the larger circle the area of the fire-box outside shell. The water line shows the comparative steam space in each of these parts. Fig. No. 3, is a plan of the fire-box, showing how the circu- lation of the water spaces is arranged, and which spaces com- municate with the cylindrical part below the tubes, as shown in Fig. 1. From these dimensions we have for the cylindrical parts : Cir. in. Sectional area of boiler = 5 8^ .... =3364 Cir. in. less tubular area of 303 tubes x 2^= . . 1212 and segmental steam space, =:^ = *155 = *07747 (tab. num.) X 58^ = 260 sq. in. X 1*273= 331 1543 Leaving a sectional water area of 1821 which multiplied by the length = 1821 x 132 = 240372 cy. in. The tubular space = 1212 area x 132 length = 159984 cy. in. The steam space = 331 area x 132 length = 43692 cy. in. 18 WATER, EIRE, AND STEAM SPACE. For the fire box or rectangular parts we have Cub. in. Front and back spaces = 71 in. x 63 in. deep x 3 in. wide x 2 = 26838 Side spaces = 60 in. x 63 in. deep x 3^ in. wide x 2 = 26460 Partition spaces = 63in. x 51 in. deep x 4 in. wide x 1 = 12852 Top of fire box = 66 in. x 9 in. deep x 69 in. wide x 1 = 40986 107136 2856 1134 4134 8193 = 16317 90819 Or by taking the space included within the outside fire box, and deducting the inside one, thus. Outside box = 71 wide x 66 long x 63 deep = 295218 Less inside box = 64 wide x 60 long x 63 deep = 241920 53298 Add partition and top as above = 53838 107136 Less deductions as above 16317 Total water space round fire box = 90819 Steam space=ff = *211 =’120713 (tab. num.) x 71^ = 609 sq. in. area, and 609 x 66 length = 40014 sq. in. steam space on top of fire box. Summary. Steam Space. Cub. in. Cy. in. or Cub. in. Cylindrical part = 43692 x ’7854 = 3431 5 Fire box part = 40014 x 1’273 = 50938 x =40014 Total steam space 94630 or 74329 Compared with the capacity of the cylinders 94630 = 18 in. diameter by 24 in. stroke = 182x 24= — — =12’17 ^ 777 ^ times the capacity of 1 cylinder, or 6 times the capacity of the two cylinders. Deduct for back tubes = 1212 cub. in. x 3 x *7854 = For front fire door = 21x18x13 = For stays of sides, ends, and partitions, ^ of space = For top of box stays of water space = WATER AND COKE SPACE IN A TENDER. 19 Water Space. Cub. in. Cy. in. or Cub. in. Cylindrical part = 240372 x '7854 = 188788 Fire box part = 90819 x 1-273 = 115612 = 90819 Total water space — 355984 or 279607. Cyl. in. Lbs. Lbs. av. Gals. bnp. 10117 And 355984 x *02842= =4*516 tons, or 4 10 1 7 2240 and 355984 x *00284 =1011-7 gallons of water. And by cubic measure. Cub. in. Lbs. Lbs.av. 10113 t. c. q. lb. 279607 x* 03617=-2^=4*514, or4 10 1 3 and 279607 x *00361 = 1011*3 gallons, being a difference of 4 lb. on the whole quantity, arising from the exponents being approximate and not strictly correct, but sufficiently near for practical purposes. Heating Space. Cub. in. Cy. in. Cub, in. Tubular space = 159984 x *7854 = 125651 Firebox = 241920x 1-273 = 307964 =241920 Total heating space = 467948 or 367571. Tabular Abstract of Boiler Contents. Cy. in. Cub. in. Ratio. Steam space = 94630 or 74329 1 Water space = 355984 or 279607 373 Heating space = 467948 or 367571 4-94 Per cent. 10*3 3875 50*95. Example 2. — Taking the dimensions of the tender water tank of the Lord of the Isles, locomotive engine, as under, required the quantity of water it will contain in lbs., in tons, and in gallons ? 20 WATER AND COKE SPACE IN A TENDER. Tender Tank. -16 = 6 - Length, 16' 6" ; width, 8' 4" ; depth, 2' 7^” ; less coke space, 7' 3" long, and 4' 2" wide and 2' 7i" deep. Cub. In. Cub. Ft. 178" X 100" X 31-5" = 523700-^ 1728 = 360*9 less 87" X 50" X 31*5"= 137025 -f- 1728= 79*3 486675 281*6. Cub. In. Lb. and 486675 x *0361 7 = 17603 lbs. which divided by 2240 = 7 tons, 17 cwt., 0 qr., 18 lbs. for gallons 486675 x *00361= 1760 gallons, or 281*6 cube ft. x 6*25= 1760 gallons. Abstract of Tender Contents. Cub. In. Ratio. Per cent. Coke space 137025 1 18 Water space 623700 4*55 82. Impurities of Water. Since nothing but pure water is converted into pure steam, and the impurities of water are either deposited on the boiler, or, by the action of chemical agents, partly carried away in the IMPURITIES OF WATER. 21 steam, to the detriment of slide-valves, and pistons ; the fol- lowing table will convey an idea of the impurities in well, river, and canal water. All the London waters are from Professor Brande’s Beport. The New Swindon water is by Dr. Ilerapath, the eminent chemist, of Bristol. Table No. 4. IMPURITIES IN one GALLON OF WATER. (70,000 grains = 1 imperial gallon.) Grains. Per cent. Thames at Greenwich 27*9'i •00398 ,, London Bridge 28- gT CO CO . •004 ,, Westminster 24*4 TO •0035 ,, Brentford . 19*2 (V > o . •00274 „ Twickenham 22*4 <5 ^ CO • •0032 „ Teddington 17*4^ •0025 New Biver 19-2 •002 Colne 21S •00304 Lea 23*7 •00338 Bavensborne, at Deptford . 20* •00285 Combe and Delafield’s Well, , deep 56*8 •0081 xlpothecaries’ Hall, Blackfriars „ 45* •00643 Notting Hill 60-6 •00865 Boyal Mint 39 37*8 •0054 Hampstead Water Works 93 40* •00571 Berkeley Square 99 60- •00857 Tilbury Fort 99 75* •01071 Coding’s Brewery 99 SO- •00714 jj shallow HO* •01571 Pd ore’s Brewery, Old Street deep 38*9 •005557 ?? shallow 110* •0157 Trafalgar Square fountains deep 68*9 •00984 St. Paul’s Churchyard 99 75* •01071 22 IMPURITIES OF WATER. Grains. Per cent. Bream’s Buildings . 115- . . -01643 St. Giles, Holborn . 105- . . -015 St. Martin’s, Charing Cross . 95- . . -01357 Postern Row, Tower . . 98- . . -OM Artesian Well at Crenelle, Paris . 9-86 . New Swindon Canal, filtered . 32-16 . . -00014 Of these a detailed analysis of the Royal Mint water, by Professor Brande, and of the New Swindon filtered canal water, by W. Herapath, Esq., of Bristol, will show the nature of these impurities. In one gallon of water from the Royal Mint well there were — Proximate saline components. Grains. CMoride of sodium . . . 10*53 Sulpliate of soda . . .13*14 Carbonate of soda . . . 8*63 „ of lime . . .3*5 ,, of magnesia . . 1*5 Silicia 0*5 Organic matter . . Phosphoric acid . . > Traces of. Iron j In one gallon of New Swindon water there were — Grains in a gallon. •464 •048 . 5744 . 2736 . 12-16 . 10*4 •608 32*16 This water averages 20 grains of hardness, as it is called, which is more than the average of the London or Bristol Chloride of magnesium (bittern) Sulphate of ,, (Epsom salts) Sulphate of soda (glauber salts) Chloride of sodium (common salt) . Carbonate of lime (chalk) . . . Sulphate of lime (gypsum) . Organic matter (vegetable extract) . isuostances in me water. Sulphuric acid . . . . Chlorine Carbonic acid (after boiling) Silicia Sodium combined with chlorine Soda combined with sulphuric 7 and carbonic acid Lime . Magnesia . Organic matter . Phosphoric acid Iron . drains. 7*44 6*31 5*84 0*50 4*22 10*87 1*96 071 Traces of. SOLVENTS OF IMPURITIES. 23 spring waters, which run from 12 to 16 grains. By boiling the water is reduced to 12 grains hardness. These analyses of water indicate that locality has much to do with its comparative purity, and that in London, the shallow wells above the chalk, or about 200 to 220 feet deep, are more impure than those deep wells which draw their supplies below the chalk, or about 400 to 426 feet deep, as at the Royal Mint. By knowing the particular impurities in any particular water, the practical engineer can decide with confidence whether it is or is not desirable to employ any chemical agent, such as oxalic acid, carbonate of potash, or soda, to precipitate, or nitric, muriatic, or acetic acid, to hold in solution and pass through with the steam some one of these impurities. If only one agent, such as muriate of ammonia, be used, which thus holds in solution one of the impurities, say car- bonate of lime, whilst the others, such as the sulphate of lime, are deposited by boiling ; then it may even be more than doubtful if there be any present gain, and scarcely doubtful as to future injury to the rubbing surfaces and to the boiler itself, whilst the presence of any foreign body in the steam necessarily impairs its efficacy. The effect of acids on iron is well known, and notwithstand- ing their dilution when used in boilers, they still appear to exercise injurious effects on particular makes of iron. In some locomotive boilers where muriate of ammonia has been employed, the internal surface of the part below the tubes was so deeply oxydized in numerous spots as to render it necessary to replace the plates to prevent accidents. In other boilers this effect is not so apparent. This difference is pro- bably owing to the quality of the iron, or to the greater or lesser quantity of oxygen or other bodies it contains, having more or less affinity for acids, as both boilers were supplied with the same water. Similar results are observed from the action of the fire upon copper fire boxes, where one fire box will last much longer than another. The advocates of these 24 DOMESTIC QUALITIES OF WATER. chemical agents deny their injurious action, but the accumu- lating evidence of observed destruction of tender tanks and boilers is a strong presumption that they cannot be used safely with every sort of iron, even if their employment were otherwise beneficial. Dr. Davies’s analysis of locomotive depo- sits shows that they contain carbonate and sulphate of lime with a little magnesia, protoxide of iron, silicia and carbona- ceous matter ; and one about one tenth of an inch thick had formed during a run of 436 miles, and the consumption of 10,900 gallons of water. Hard and Soft Water for Domestic Use.^ Since water for domestic use is still more important to the public generally, the following remarks on its household pro- perties will usefully conclude this chapter. ‘‘ The popular expressions hard and soft water really give little information concerning the wholesomeness or character of a particular water, and its adaptation for drinking or culinary or even washing purposes. Water may be ' soft,’ free from or- ganic impurit}^, but, owing to the presence of a large quantity of mineral matter, be quite unfitted for drinking, cooking, or even for washing. To give a practical illustration : the water sup- plying the Trafalgar Square fountains, and which is lifted from a well sunk into the chalk formation beneath the London clay, the bottom of which is about 350 feet below the level of the sea, is a ^soft’ water about 5|° of hardness ; but this water contains, according to the analysis of Mr. Brande and the Eoyal College of Chemistry, from 66 to 79 grains of mineral matter per gallon, from 60 to 72 grains of which are common salt and soda : water of this description is unfitted for drinking or making tea, and some other culinary operations, because the soda contained in it, when habitually used, acts medicinally on the kidneys ; and ^ S. C. Homersham, on the Supply of Water to the Metropohs. J. Weale, London. HARD AND SOFT WATER. 25 it is unfitted for washing, because the effect of soda, if used for washing clothes, tends to discolour white cotton, flannel, or linen, and to spoil the colours of certain prints ; it is also un- fitted for warm baths, because the soda is apt to form a soap with the oily matter which exudes from the pores of the skin, and therefore causes it to become rough and chap. On the other hand, water may be ‘ soft ’ from the almost entire absence of mineral matter in solution ; water of this description, from only 1^ to 2^ of hardness, may be found in streams fed from the rain falling upon the primi- tive geological formations. I have had water analyzed that was collected from streams fed by the rain falling upon the millstone-grit formation containing only 2J grains of mineral matter per gallon, and only lyoth degree of hardness, and yet the use of this water for most purposes is avoided by the in- habitants living near these streams, because a large portion of the ground draining into them is covered with peat, which, being taken into solution, and especially in summer weather, so completely contaminates the water with organic matter, that it is unfitted for drinking ; for, when so used, it pro- duces sickness and diarrhsea. These streams, especially after heavy rains in the summer time, are discoloured with peat, and if used for washing, stain the coarsest linen and dim the bright colours of printed goods. This water is also bad for making tea, and spring water of a somewhat harder character (about 4^ of hardness) is used in preference for this purpose ; because, as the inhabitants express it, such very soft water draws out the wood of the tea, and spoils the flavour. ^^It may be noted that M. Soyer states as the result of his experiment upon tea-making, that ‘the softest or distilled water had an extraordinary power in obtaining a quick extract ; the result showed perhaps too high a power ^ for it draws out the woody flavour^ It is some years since my attention was first practically drawn to the fact that water might be too soft c 26 HARD AND SOFT WATER. for the making of tea, and M. Soyer’s evidence accords with popular experience in this respect. It may not be out of place to mention here that carbonate of soda, when added to a solution of tea, deepens the colour of the tea, without either improving the flavour or the strength ; any one may prove this by pouring out a cup of tea and sepa- rating it from the grouts ; if a small quantity of carbonate of soda be added to such a solution, the colour will be sensibly deepened, although it is quite evident that the strength of the tea is no greater after the addition of the soda than before. This fact may account for M. Soyer stating, that the water procured from the deep well of the Reform Club and Trafalgar Square fountains (both of which waters contain a quantity of carbonate of soda) ranks number one for tea-making ; M. Soyer being doubtless misled by the colour of the infusion. His taste, being habituated to a water containing soda, would not he offended by the taste of this alkali. As we see, then, water may be. ^ soft ’ and free from organic matter, and yet, from the presence of a large quantity of alkaline salts, be unfitted for nearly all domestic uses. Wa- ter may also be ‘ soft ’ from the almost entire absence of salts, and yet from its high extractive power he unfitted for tea- making ; while such water, especially in summer, when col- lected from the drainage of land covered with peat, or even vegetation of any kind, takes greedily in solution organic mat- ter, which renders it unwholesome for drinking, and when dis- coloured with peat, quite i^nfitted for washing purposes. ‘‘ It is only when ‘ soft ’ water is free from alkaline salts, and devoid of organic matter in solution, that it can be con- sidered as fitted for domestic purposes. Spring w^ater issuing from the millstone grit, and other primitive formations, is often of this character ; hut the soft surface water collected in reservoirs, and used to supply Preston, Bury, Ashton, and other towns in Lancashire, is not good drinking water, owing to its containing, in the summer, organic matter ; and it is a pity, HEAT. 27 that when Dr. Sutherland was directed to make hi» ^ local in- vestigations ’ in Scotland and Lancashire, he was not in- structed to inquire particularly into the amount of organic matter contained during autumn and summer weather in the ^ soft ’ water collected in reservoirs for the use of town popula- tions ; had he done so, he would have discovered, what is well known to all practically acquainted with the subject, that the great bulk of such waters, at these seasons, is impregnated with organic impurities. The term hard water is equally indefinite as soft water. ^ Hard ’ water may be ^ hard ’ from holding in solution (as ex- plained in the body of the Keport) a certain amount of either lime salts or magnesian salts ; and the character of a lime salt or magnesian salt again varies according as it may be com- bined with carbonic acid on the one hand, sulphuric acid, nitric acid, or any other acid, on the other hand. The quality and adaptation of a ^hard’ water for domestic purposes is very different, according as it may be ^ hard ’ from the presence of magnesia or lime, or of both these salts ; so that it is only by knowing the amount and character of the mineral matter from which a water derives its ^ hardness ’ that its wholesome- ness or unwholesomeness, and its adaptation for domestic pur- poses, can be predicted. Again : ^ hard ’ water may be contaminated, especially when warm, with excremental or organic matter in solution, although it is not so rapidly poisoned with these impurities as ^ soft ’ water when free from alkaline salts.” CHAPTER II. HEAT. This widely- diffused body has led to much learned discus- sion on its nature, without arriving at any definite result. Its effects are apparent to all, but its nature is yet conjectural. c 2 28 EXPANSION OF SOLIDS Its measurable quantity is comparatively ascertained by an instrument called a thermometer^ and the quantity indicated on a scale of equal parts is designated its temperature. The general effect of heat upon all bodies is to increase their bulk in some unascertained ratio to their density and molecular formation, excepting those bodies which diminish in volume, by heat evaporating the water they contain, such as newly-cut peat or clay. Solids expand least, fluids next, and gases most by equal increments of heat. As compared with each other, neither solids nor fluids of the same class expand equally, a fact which has hitherto prevented any general law being defined for the rate of expansion of each class. Usually, though not always, the lighter bodies expand more than the heavier ones, as alcohol expands more than water, and water more than mercury. Platinum, gold, silver, and zinc follow the general law, but copper, iron, and marble form exceptions. The following Table, No. 5, shows the lineal expansion of solid bodies, from 32° to 21.2° by different experimenters. In such delicate experiments uniformity of results is not to be expected, yet the averages may be taken as given in Table No. 6. Table No. 5. LINEAR EXPANSION OF SOLIDS AT 212° TAKING THE LENGTH OF THE BAR. AT 32° FAHR. AS 1 FOOT. Name. Experimenter. Length at 212®. Feet. Glass tube . . Ditto . . . . . Ditto ..... Ditto . . . . . Ditto Plate glass . . . . Ditto crown glass Ditto Ditto ..... Smeaton Roy Delucas mean Dulong and Petit . . Lavoisier and Laplace Ditto . . . . Ditto .... Ditto . . . . Ditto .... 1*00083333 1*00077615 1*00082800 1*00086130 1*00081166 1*00089089 1*00087572 1*00089760 1*00091751 BY HEAT. 29 Name. Experimenter. Length at 212°, Feet. Glass rod Roy 1-00080787 Platiaa purified Roy, as glass 1-000857 Platina . Borda . . . . 1-00085655 Ditto .... . Dulong and Petit . 1-00088420 Ditto. . . Troughton . . . 1-00099180 Ditto and glass . Berthoud 1-00110000 Palladium , Wollaston . . . 1-00100000 Antimony . . Smeaton 1-00108300 Cast-iron prism Roy 1-00110940 Cast-iron Lavoisier, by Dr. Young . 1-00111111 Steel . Troughton . . . 1-00118990 Ditto rod . . Roy .... 1-00114470 Blistered steel . Phil. Trans. 1795, p. 428. 1-00112500 Ditto .... Smeaton 1 00107875 Steel not tempered . . Lavoisier and Laplace 1-00107956 Ditto .... Ditto .... 1-00107956 Ditto tempered yellow . Ditto . . . . 1-00136900 Ditto .... . Ditto .... 1-00138600 Ditto at a higher rate Ditto . . . . 1-00123956 Steel .... Troughton . . 1-00118980 Hard steel . Smeaton . . . . 1-00122500 Annealed steel Musschenbrock 1-00122000 Tempered steel . Ditto . . . . 1-00137000 Iron .... . Borda .... 1-00115600 Ditto Smeaton . . . . 1-00125800 Soft iron forged . . Lavoisier and Laplace 1-00122045 Round iron, wire drawn , Ditto . . . . 1-00123504 Iron wire . Troughton 1-00144010 Iron Dulong and Petit . . 1-00118203 Bismuth , Smeaton 1-00139200 Annealed gold . Musschenbrock . . 1-00146000 Gold .... Ellicot, by comparison 1-00150000 Ditto, procured by parting . Lavoisier and Laplace 1-00146606 Ditto, Paris standard Ditto .... 1-00155155 Ditto, pure hammered Ditto .... 1-001514 Ditto, ditto, annealed Ditto . . . . 1-00151361 Copper Musschenbrock 1-00191080 Ditto . Lavoisier and Laplace 1-00172244 Ditto .... Ditto .... 1-00171222 Ditto Troughton 1-00191880 Ditto .... . Dulong and Petit . 1-00171821 Brass . Borda . . . . 1-0O17830O Ditto .... . Lavoisier and Laplace 1-00186671 Ditto . Ditto . . . . 1-00188971 Brass scale, supposed from 1 Hamburgh . , . J Roy .... 1-00185540 Cast brass . Smeaton . . * * | 1-00187500 30 EXPANSION OF SOLIDS Name. Experimenter. Length at 212°. Feet. English plate brass, in form Ditto, in a trough form . Roy .... 1-00189280 . Ditto . . . . 1-00189490 Brass . . . . . Troughton 1-00191880 Ditto wire » . . . Smeaton . . . . 1-00193000 Brass Musschenbrock 1-00216000 Copper 8, tin 1 . Smeaton . . . . 1-00181700 Silver . . . . . Herbert 1-00189000 Ditto Ellicot, by comparison . 1-00210000 Silver . . * . . Musschenbrock 1-00212000 Ditto of cupel Lavoisier and Laplace 1-00190974 Ditto, Paris standard . . Ditto .... 1-00190868 Silver .... Troughton . . . 1-00208260 Brass 16, tin 1 . . . Smeaton 1-00190800 Speculum metal . Ditto .... 1-00193340 Spelter solder ; brass 2, zinc 1 Ditto . . . . 1-00205800 Malacca tin ... Lavoisier and Laplace 1-00193765 Tin from Falmouth . . Ditto . . . . 1-00217298 Fine pewter Smeaton 1-00228300 Grain tin . ... Ditto . . . . 1-00248300 Tin Musschenbrock 1-00284000 Soft solder ; lead 2, tin 1 Smeaton . . . . 1-00250800 Zinc 8, tin 1, a little ham-1 mered . . . . J Ditto .... 1-00269200 Lead ..... Lavoisier and Laplace 1-00284836 Ditto . . . . . Smeaton 1-00286700 Zinc ..... Ditto . . . . 1-00294200 Ditto, hammered out half- ] inch per foot . . J Ditto .... 1-00301100 Glass, from 32° to 212° Dulong and Petit . . 1-00086130 Ditto, from 212° to 392° . . Ditto .... 1-00091827 Ditto, from 392° to 572" . Ditto . . . , 1-000101114 The linear expansion multiplied by three gives the total expansion nearly. Thus for iron it would be 1 in 271, and for lead 1 in 1 1 7 to be considered in buildings ; or, as in the instance of Bow Church spire, it may endanger the structure. The contracting power of expanded iron is usefully employed in various ways, and was the means used to draw the walls of the Museum of Arts in Paris from an inclining to a vertical position. The strain on many parts of locomotive engines from the unequal temperature and expansion of copper, brass, and iron will be readily calculated by the following averages which divided by three give the ratio of increased bulk. AND FLUIDS BY HEAT. 31 Table No. 6. AVERAGES OF A FEW OF THE PRINCIPAL SOLIDS. Averages of the Linear Expansion of Metals from 32"^ to 212®. Name. Increased length at 212°. Zinc sheet, 1 part in . . 340 Zinc, cast, ,, . . 322 Lead ,, . . 351 Tin, pure, ,, . . 403 Tin, impure, ,, . . 516 Silver, ,, . . 524 Copper, ,, . . 581 Brass, ,, . . 584 Gold, „ . . 682 Bismuth, ,, . . 719 Name. Increased length at 212°. Iron, 1 part in . . 812 Antimony ,, . . 923 Palladium, ,, . . 1000 Platinum, ,, . . 1167 Glass, ,, . . 1160 Marble, ,, . . 2833 Iron, soft ,, . . 818 Iron, cast ,, . . 900 Steel, tempered ,, . . 806 Steel ,, . . 926 Sheet zinc as employed on roofs of buildings or for covering locomotive boilers, exhibits in a marked manner the effects of expansion, in causing it to blister and crack,” which renders it an inferior article for such purposes. The following tables will further illustrate this property of heat. Table No. 7. EXPANSION OF FLUIDS BT THE ADDITION OF 180° OF HEAT, OB AT 212'' TAXING THE BULK OR VOLUME AT 32° AS 1 CUBIC FOOT. Name. Cub. ft. Cub. ft. Air 1 part in 2*73 or 1000 become 1366 Alcohol 1 9 1000 1110 Nitric acid (s. g. 1*4) 1 9 1000 1111 Fixed oils 1 12 1000 1083 Turpentine 1 14 1000 1071 Sulphuric ether . 1 14 1000 1071 Sulphuric acid (s. g. 1-85) 1 17 1000 1058 Muriatic acid (s. g. 1*137) 1 17 1000 1058 Salt water 1 20 1000 1050 Water 1 22 1000 1045 Mercury 1 55 1000 1018 Mercury, apparent in glass 1 64 1000 1015. 32 THERMOMETERS. Table No. 8. COMPARATIVE EXPANSION OE WATER AND AIR BT HEAT. Deg. Fall. Water. Air. Deg. Eah. Water. Air. 12 1*00236 122 1*01116 1*198 22 1*00092 132 1*01367 1*219 32 1*00022 1*000 142 1*01638 1*239 40 1*00000 1*021 152 1*01934 1*259 52 1*00021 1*047 162 1*02245 1*279 62 1 00083 1*071 172 1*02575 1*299 72 . 1*00180 1*093 182 1*02916 1*319 82 1*00312 1*114 192 1*03265 1*338 92 1*00477 1*136 202 1*03634 1*357 102 112 1*00672 1*00880 1*156 1*177 212 1*04012 1*376 Thermometers, The general law of expansion by heat, as shown in these tables, suggested the mode of measuring the heat in any body by comparison with the rate of expansion in a given body. The medical advantages of determining the compara- tive temperatures of the body and the air in sick chambers, led Sanctori, an Italian physician, to construct an air ther- mometer in 1590, to aid him in his practice, being the earliest we have an account of. In 1655 alcohol was substituted for air, and although both air and spirit thermometers are still employed in scientific investigations at very high or very low temperatures, mercurial thermometers are generally used. The qualities of mercury for the thermometer are its fluidity through a range of nearly 700^ under atmospheric pressure, and about 630° in the vacuum of a thermometer, where its fluidity extends below the freezing point of water, about 40°, and above its boiling point, 378”. It is not, however, a perfect instrument, as its rate of expansion increases for equal incre- ments of heat at high temperatures, and it also deteriorates by use, which renders it necessary to check its indications for minute investigations by the more uniform expansion of the air thermometer. Quicksilver was its original name, but the alchemists of MERCURIAL THERMOMETER. 33 old fancied that the metals had some mysterious relation to the heavenly bodies. Thus they called : Gold, the Sun ; Silver, Moon ; Quicksilver, Mercury ; Copper, Venus ; Iron, Mars ; Tin, Jupiter ; Lead, Saturn. If they were unable to find the elixh' vitce, or the philosopher’s stone, yet amid their visionary schemes, science is indebted to their researches, and quicksilver retains the name they gave it in ordinary use. Asa metal, mercury has a beautiful silvery appear- ance, and both in art and in medicine it is extensively employed. The following are a few of its exponents; like other instances of the same kind experimentalists do not all give the same exponents. Its specific gravity when solid at 40° below zero, is 13*64 times the weight of water of an equal bulk. At 60° it is 13*58; at 212° it is 13*37, and at 590° it begins to boil in the ther- mometer, but not until 660° in the open air. Mercurial Thermometer, This instrument is usually made with a slender glass tube of equal bore, having an enlarged end, which, with a part of the tube, is filled with mercury. It is then made to boil, that the expansion of the mercury may expel the air from the unfilled part of the tube, when the open end is fused together to prevent the admission of any more air. Thus enclosed from the pressure of the atmosphere, the mercury ascends by expansion as heat is communicated to it, or descends by con- traction as heat is withdrawn from it. To give two fixed points in a scale of parts for the rise and fall of mercury, Dr. Hook suggested, and Sir I. Newton adopted the freezing and boiling points of water for that purpose, which is still acted upon. These points are obtained hyimmersing the prepared tube con- taining mercury, alternately in freezing and boiling water, and marking the level at which the mercury becomes stationary in each trial. The distance between these points is then divided into a number of equal parts, and the scale extended as required. In this country thermometers are understood to be so adjusted, when the pressure of the air supports 30 inches of mercury. c 3 34 VARIOUS Although philosophers have agreed on the fixed points of the thermometric scale, it is greatly to be regretted that they have not equally agreed on its division into equal parts, and not complicated research by a variety of scales. The dis- tance between the freezing and boiling points is by Fahrenheit divided into ISO parts, by De Lisle into 150 parts, by Celsius into 100 parts, and by Reaumur into 80 parts, all in use in different parts of Europe. Diagrams, Nos. 4, 5, 6, 7, will show the relation these scales bear to each other. In g O ^ « ^ . ^ o 2^; C C 1 , o o g , ! II s : ® S 3 (D o O H|« i«|OJ >— • ‘ - rd O ra P-l o o ^|U5 r* 5 O < (N "lU r— I In ... ‘ 3 4J ^ § Q o o o 1—1 «._i o o il« HU5 iO O .55i P? pS ^3 S pqsQ ^ THERMOMETERS 35 Comparatively, therefore, the preceding thermometers stand thus : — Boiling Fahr. 212 De Lisle. 0 Celsius or Cent. 100 Reaum. 80 Freezing 32 150 0 0 No. of equal parts = 180 150 100 80 Ratio of parts = 9 7-5 = 5 = 4 or thus : — 1° of Fahr. = f of 1 of De Lisle’s orFahr. x f = De Lisle’s. 1 „ = f of 1 of Cent. ,, xf = Cent. 1 „ = ^ of 1 of Reaum. ,, x^ = Reaum. 1° of De Lisle’s = 1^ of 1 of Fahr. or De Lisle’s x f = Fahr. 1 ,, of 1 of Cent. ,, X ■^ = Cent. 1 ,, =- 5 -% of 1 of Reaum. ,, Xy®^ = Reaum. 1° of Cent. = of 1 of Fahr. or Cent. 1 ,, =1^ of 1 of De Lisle’s ,, 1 ,, = ^oflofReaum. ,, X § = Fahr. X § = De Lisle’s. X ^ = Reaum. 1° of Reaum. 1 = 2i of 1 of Fahr. or Reanm. x f = Fahr. = If of 1 of De Lisle’s ,, x =De Lisle’s. = 1^ of 1 of Cent. ,, X f = Cent. The multipliers are thus used — 180 Fahr. x f =^^^ = 150° De Lisle’s. 1 ^ 0 V fi 150 DeLisle’s x f or =180“ Fahr. or 150 x 1-2 = 180° Fahr. 80 Reaum. x ^/ = — ^ = 150° De Lisle’s. 180 Fahr. x f =^^^^ = 100 Cent. 100 X 9 100 Cent. X f or 1*8 = — - — =180 Fah. ^ 5 or 100 x 1-8 = 180° Fahr. 36 VARIOUS. Whilst by these multipliers we are enabled to convert the degrees of one into those of the other, yet, as their notation is different, it requires attention to subtract the 32° of Fahren- heit from the reading off other scales, before the multiplier is used. Thus, Fahr. 212°— 32 x | = 100° Cent. From the freezing point to zero, it requires the number for a Fahrenheit scale to be subtracted from 32°. Thus, Fahr. 14, then 32— 14x|=10 Cent. Below zero, it requires the 32° to be added. Thus, Fahr. - 58° + 32° x | - 50° Cent, and in like manner with Reaumur’s scale. De Lisle’s notation commencing at 212^ Fahrenheit’s, 100° Cent, and 80° Reaumur, requires the quantity found by the multipliers to be deducted from 150° for the reading on his scale : thus 206 Fah. = 5 De Lisle’s, for 206-32 X 5 , . , 7^ = 145 and 150— 145 == 5° De Lisle s. o For it will be observed they differ in their zero or starting point as well as in their scale of parts. In 1/09 Fahrenheit having artificially obtained a degree of cold 32° below the freezing point of water, imagined it to be the greatest possible cold, and fixed it as the starting point for his scale used in this country. Recent experiments have, however, gone as low as 448° below Fahrenheit’s zero, and Dulong and Petit regard the point w*here heat is not to be found at all, as undefinable. As cold is only the expression for the comparative absence of heat, the greatest degree of cold it appears is not determin- able. In 1730 Reaumur fixed his zero at the freezing point, so also did Celsius, whose scale is used in France , but in 1 733, De Lisle fixed his zero at the boiling point. Thus, in reading off De Lisle’s own scale, say at 80°, it would be 150° (the range between boiling and freezing) — 80 = 70° above the freezing point. From this brief explanation of the principal thermometers THERMOMETERS. 37 it will be obvious that one uniform scale, such as the centi- grade or decimal scale, would be far preferable for both scien- tific and practical purposes, than a constant recourse to cal- culation to ascertain the comparative temperatures. In this respect the following table will be found useful. Table No. 9. COMPARATIVE TEMPERATURES OP FAHR., DE LISLE, CELSIUS, REAUM., FROM 600^ FAHR. TO FREEZING POINT OF MERCURY. Fahr. De Lisle. Celsius. Reaum. Fahr. De Lisle. Celsius. Reaum. 600 323-3 315-5 252-4 338 105- 170- 136- 580 306-6 304-4 243-5 337 104-1 169-4 135-5 560 290-6 293-3 234-6 336 103-3 168-8 134-1 540 273-3 282-2 225-7 335 102-5 168-3 134-6 520 256-6 271-1 216-8 334 101-6 167.7 134-2 500 240- 260- 208- 333 100-8 167-2 133-7 490 231-6 254-4 203-5 332 100- 166-6 133-3 480 223-3 248-8 199-1 331 99-1 166-1 132-8 470 215- 243-3 194-6 330 98-3 165-5 132-4 460 206-6 237-7 199-2 329 97-5 165- 132- 450 198-3 232-2 185-8 328 96-6 164-4 131-5 440 190- . 226-6 181-4 327 95-8 163-8 131-1 430 181-6 221-1 176 8 326 95- 163-3 130-6 420 173-3 215-5 172-4 325 94-1 162-7 130-2 410 165- 210- 168- 324 93-3 162-2 129-7 400 156-6 204-4 163-5 323 92-5 161-6 129-3 395 152-4 201-6 161-3 322 91-6 161-1 128-8 390 148-3 198-8 159-1 321 90-8 160-5 128-4 385 144-1 196-1 156-9 320 90- 160- 128- 380 140- 193-2 154-6 319 89-1 159-4 127-5 375 135-8 190-5 152-4 318 88-3 158-8 127-1 370 131-6 187-7 150-2 317 87-5 158-3 126-6 365 127-5 185- 148- 316 86-6 157-7 126-2 360 123-3 182-2 145-8 315 85-8 157-2 125-7 355 119-16 179-4 143-5 314 85- 156-6 125-3 350 115- 176-6 141-3 313 84-1 156-1 126-8 345 110-83 174- 139- 312 83-3 155-5 124-4 340 106-6 171-1 136-8 311 82-5 155- 124- 339 105-8 170-5 136-4 310 81-6 154-4 123-5 :8 COMPARATIVE SCALES Fahr. De Lisle. Celsius. Reaum. Fahr. De Lisle. Celsius. Reaum. 309 80*8 153*8 123*1 265 44*1 129*4 103*5 308 80 - 153*3 122*6 264 43*3 128*8 103*1 307 79-1 152-7 122*2 263 42*5 128*3 102*6 306 78-3 152*2 121-7 262 41*6 127-7 102*2 305 77-5 151*6 121*3 261 40*8 127-1 101*7 304 76-6 151*1 120*8 260 40 * 126-6 101*3 303 75-8 150*5 120*4 259 39*1 126.1 100*8 302 75 - 150 * 120 * 258 38*3 125-5 100*4 301 74-1 149*4 119*5 257 37*5 125 - 100 * 300 73-3 148*8 119*1 256 36*6 124-4 99*5 299 72-5 148*3 118*6 255 35*8 123-8 99*1 298 71-6 147-7 118-2 254 35 * 123-3 98*6 297 70-8 147*2 117-7 253 34*1 122-7 98*2 296 70 - 146*6 117-3 252 33*3 122-2 97*7 295 69-1 146*1 116*8 251 32*5 121-6 97*3 294 68-3 145*5 116*4 250 31*6 121-1 96*8 293 67.6 145 * 116 * 249 30*8 120-5 96*4 292 66*6 144*4 115*5 248 30 * 120 - 96 * 291 65-8 143*8 115*1 247 29*1 119-4 95*5 290 65 - 143*3 114*6 246 28*3 118-8 95*1 289 64*1 . 142*7 114*2 245 27*5 118-3 94*6 288 63*3 142*2 113*7 244 26*6 117-7 94*2 287 62*5 141*6 113*3 243 25*8 117-2 93*7 286 61-6 141*1 112*8 242 25 * 116-6 93*3 285 60-8 140*5 112*4 241 24*1 116-1 92*8 284 60 * 140 * 112 * 240 23*3 115*5 92*4 283 59-1 140*4 111*5 239 22*5 115 * 92 * 282 58-3 139*8 111*1 238 21*6 114*4 91*5 281 57-5 139*3 110*6 237 20*8 113*8 91*1 280 56-6 138*7 110*2 236 20*0 113’3 90*6 279 55-8 138*2 109*7 235 19*1 112*7 90*2 278 55 - 137*6 109*3 234 18*3 1 ] 2*2 89*7 277 54-1 136*1 108*8 233 17*4 111^6 89*3 276 53*3 135*5 108*4 232 16*6 111*1 88*8 275 52-5 135 * 108 * 231 15*8 110*5 88*4 274 51-6 134*4 107*5 230 15 * 110 * 88 * 273 50-8 133*8 107*1 229 14*1 109*4 87*5 272 50 * 133*3 106*6 228 13*3 108*8 87*1 271 49-1 132*7 106*2 227 12*5 108*3 86*6 270 48-3 132*2 105*7 226 11*6 107*7 86*2 269 47*5 131*6 105*3 225 10*8 107*2 85*7 268 46*6 131*1 104*8 224 10 * 106*6 85*3 267 45*8 130*5 104*4 223 9*1 106*1 84*8 266 45 * 130 * 104 * 222 8*3 105*5 84*4 or THERMOMETERS. 39 Fahr. Dc Lisle. Celsius. Reaum, Fahr. De Lisle. Celsius. Reaum. 221 7-5 105 * 84 * 177 29*1 80*5 64*4 220 6-6 104*4 83.5 176 30 * 80 * 64 * 219 5-8 103*8 83*1 175 30*8 79*4 63*5 218 5-0 103*3 82*6 174 31*6 78*8 63*1 217 4*1 102-7 82*2 173 32*5 78*3 62.6 216 3-3 102*2 81-7 172 33*3 77*7 62*2 215 2-5 101*6 81*3 171 34*1 77*2 61*7 214 1-6 101*1 80*8 170 35 * 76*6 61*3 213 •8 100*5 80*4 169 35*8 76*1 60*8 212 zero 100 * 80 * 168 36*6 75*5 60*4 211 •8 99*4 79-5 167 37*5 75 * 60 * 210 1-6 98*8 79-1 166 38*3 74*4 59*5 209 25 98*3 78-6 165 39*1 73*8 59*1 208 3*3 97-7 78-2 164 40 * 73*3 58*6 207 4-1 97-2 77*7 163 40*8 72*7 58*2 206 50 96*6 77-3 162 41*6 72*2 57*7 205 5*8 96*1 76-8 161 42*5 71*6 57*3 204 6*6 96*5 76-4 160 43*3 71*1 56*8 203 7-5 95*0 76 - 159 44*1 70*5 56*4 202 8-3 94*4 75-5 158 45 * 70 * 56 * 201 9*1 93*8 75-1 157 45*8 69*4 55*5 200 10 - 93*3 74-6 156 46*6 68*8 55*1 199 10*8 92*7 74-2 155 47*5 68*3 54*6 198 11*6 92*2 73-7 154 48*3 67*7 54*2 197 12-5 91*6 73-3 153 49*1 67*2 53*7 196 13-3 91*0 72-8 152 50 * 66*6 53*3 195 14-1 90*5 72-4 151 50*8 66*1 52*8 194 15 - 90 * 72 - 150 51*6 65*5 52*4 193 15-8 89*4 71-0 149 52*5 65 * 52 * 192 16*6 88*8 71-1 148 53*3 64*4 51*5 191 17-5 88*3 70-6 147 54*1 63*8 51*1 190 18-3 87*7 70-2 146 55 * 63*3 50*6 189 19-1 87*2 69 7 145 55*8 62*7 50*2 188 20 - 86*6 69-3 144 56*6 62*2 49*7 187 20-8 86*1 68-8 143 57*5 61*6 49*3 186 21-6 85*5 68-4 142 58*3 611 48*8 185 22-5 85 * 68 - 141 59*1 60*5 48*4 184 23*3 84*4 67-5 140 60 * 60 * 48 * 183 24-1 83*8 67-1 139 60*8 59*4 47*5 182 25 - 83*3 66-6 138 61*6 58*8 47*1 181 25-8 82*7 66-2 137 62*5 58*3 46*6 180 26-6 82*2 65-7 136 63*3 57*7 46*2 179 27-5 81*6 65-3 135 64*1 57-2 45*7 178 28*3 81*1 64-8 134 65 * 56*6 45*3 40 COMPARATIVE SCALES OF Fahr. De Lisle. Celsius. Reaum. Fahr. De Lisle. Celsius. Reaum. 133 65-8 56*1 44*9 89 102*5 31*6 25*3 132 66-6 55*5 44*4 88 133*3 31*1 24*8 131 67-5 55 - 44 - 87 104*1 30*5 24*4 130 68-3 54*4 43*5 86 105 * 30 * 24 * 129 69 1 53*8 43*1 85 105*8 29*4 23*5 128 70 - 53*3 42 6 84 106*6 28*8 23*1 127 70-8 52-7 42*2 83 107*5 28*3 226 126 71-6 52*2 41-7 82 108*3 27*7 22*2 125 72-5 51*6 41*3 81 109*1 27*2 21*7 124 73-8 51*1 40*8 80 110 * 26*6 21*3 123 741 50.5 40*4 79 110*8 26*1 20*8 122 75 * 50 * 40 * 78 111*6 25*5 20*4 121 75-8 49*4 39*5 77 112*5 25 * 20 * 120 76-6 48*8 39*1 76 113*3 24*4 19*5 119 77-5 48*3 38*6 75 114*1 23*8 19*1 118 78-3 47-7 38*2 , 74 115 * 23*3 18*6 117 79-1 47-2 37-7 73 115*8 22*7 18*2 116 80 * 46*6 37-3 72 116*6 22*2 177 115 80-8 46*1 36*8 71 117*5 21*6 17*3 114 81*6 45*5 36*4 70 118*3 21*1 16*8 113 82-5 45 - 36 * 69 119*1 20*5 16*4 112 83-3 44*4 35*5 68 120 * 20 * 16 * 111 84*1 43*8 35*1 67 120*8 19*4 15*5 110 85 - 43*3 346 66 121*6 18*8 15*1 109 85-8 72*7 34*2 65 122*5 18*3 14*6 108 86-6 42*2 33*7 64 123*3 17*7 14*2 107 87*3 41*6 33*3 63 124*1 17*2 13*7 106 88-3 41*1 32*8 62 125*0 16*6 13*3 105 89-1 40*5 32*4 61 125*8 16*1 12*8 104 90 - 40 * 32 - 60 126*6 15-5 12*4 103 90*8 39*4 31*5 59 127*5 15 * 12 * 102 91-6 38*8 31*1 58 128*3 14*4 11*5 101 92-5 38*3 30*6 57 129*1 13-8 11*1 100 933 37*7 302 56 130 * 13*3 106 99 94*1 37*2 29*7 55 130*8 12-7 10*2 98 95 - 36*6 29*3 54 131'6 12*2 9*7 97 95-8 361 28*8 53 1325 11*6 9*3 96 96-6 35*5 28*4 52 133*3 11*1 8*8 95 97*5 35 * 28 * 51 134*1 10*5 8*4 94 98-3 34 - 27*5 50 135 * 10 * 8 * 93 99*1 33*4 27-1 49 135*8 9*4 7*5 92 100 - 33*8 26*6 48 136*6 8*8 7*1 91 100*8 32-7 26*2 47 137*5 8*3 6*6 90 101*6 32*2 25*7 46 138*3 7*7 6*2 THERMOMETERS. 41 Fahr. De Lisle. Celsius. Reaum. Fahr. De Lisle. Celsius. Reaum. 45 139 1 7-2 5-7 1 175-8 17-2 13-7 44 140 - 6-6 5-3 zero 176-6 17-7 14-2 43 143-8 6-1 4-8 1 175-8 18-3 14-6 42 141-6 5-5 4-4 2 178-3 18-8 15-1 41 142-5 5 - 4 - 3 179-1 19-4 15-5 40 143-3 4-4 3-5 4 180 - 20 - 16 - 39 144-1 3-8 3-1 5 180-8 20-5 16-4 38 145 - 3-3 2-6 6 181-6 21-1 16-8 37 145-8 2-7 2-2 7 182-5 21-6 17-3 36 146-6 2-2 1-7 8 183-3 22-2 17-7 35 147-5 1-6 1-3 9 184-1 22-7 18-2 34 148-3 1-1 0-8 10 185 * 23-3 18-6 33 149-1 0-5 0-4 11 185-8 23-8 19-1 32 150 - zero zero 12 186-6 24-4 19-5 31 150-8 05 0-4 13 187-5 25 - 20 - 30 151-6 1-1 0-8 14 188-3 25-5 20-4 29 152-5 1-6 1-3 15 189-1 26-1 20-8 28 153-3 22 1-7 16 190 - 26-6 21-3 27 154-1 2-7 2-2 17 190-8 27-2 21-7 26 155 - 3-3 2-6 18 191-6 27-7 22-2 25 155-8 3-8 3-1 19 192-5 28-3 22-6 24 156-6 4-4 3-4 20 193-3 28-8 23-1 23 157-5 5 - 4 - 21 194-1 29-4 23-5 22 158-3 5-5 4-4 22 195 - 30 - 24 * 21 159*1 6-1 4-8 23 195-8 30-5 24*4 20 160 - 6-6 5-3 24 196-6 31-1 24 8 19 160-8 7*2 5-7 25 197-5 31-6 25-3 18 161-6 7.7 6-2 26 198-3 32-2 25-7 17 162-5 8-3 6-6 27 199-1 32-7 26-2 16 163-3 8-8 7-1 28 200 * 33-3 26-6 15 164-1 9-4 7-5 29 200-8 33 8 27-1 14 165 * 10- 8- 30 201-6 34-4 27-5 13 165-8 10-5 8-4 31 202-5 35 - 28 - 12 166-6 11-1 8-8 32 203-3 35-5 28-4 11 167-5 11-6 9-3 33 204-1 36-1 28-8 10 168-3 12-2 9-7 34 205 - 36-6 29-5 9 169-1 12-7 10-2 35 205-8 37-2 29-7 8 170 - 13 3 10-6 36 206-6 37-7 30-2 7 170-8 13-8 11-1 37 207-5 38-3 30-6 6 171-6 14-4 11-5 38 208-3 38-8 31-1 5 172-5 15 - 12- 39 209-1 39-4 31-5 4 173-3 15 5 12-4 40 210- 40 - 32 - 3 174-1 16-1 12-8 41 210-9 40-5 32-4 2 175 * 16-6 13-3 42 211-6 41-1 32-9 42 EFFECTS The following table exhibits a few of the effects of heat, which may be instructive. Table No. 10 . EFFECTS OF HEAT. Fahr. below zero. Artificial cold produced by Thelorier . 133 Solid alcohol and carbonic acid . . melts 121 Artificial cold produced by Walker . 91 Natural cold observed by Ross . 60 ,, ,, of planetary space (Fourc.) . 58 ,, ,, observed by Parry . . 55 ,, ,, ,, at Hudson^s Bay . . 50 ,, ,, ,, at Glasgow, 1780 . . 23 Liquid ammonia . melts 46 Nitric acid (sp. gr. 1*424) . melts 46 boils 210' Mercury .... . freezes 39 boils 660' expands 1 in from 32 to 212, or 1*80 per cent. ,, 1 in 54^ from 212 to 392, or 1*83 ,, ,, 1 in 53 from 392 to 472, or 1*88 ,, ,, 1 in 64*8 in glass tubes,* or 1’54 ,, Dulong and Petit. Creosote Oil of vitriol Bromine . Water 1, alcohol 1 ,, 1, snow 1 . ,, 1, salt 3 ,, 78, salt 22 . Turpentine Strong wine still fluid at 17 boils 397° . freezes 13 . melts 10 boils 117° . temp. 7 . temp, zero of Fab. . temp. 4 above zero . temp. 7 . freezes 14 boils 314*^ . freezes 20 Blood, human, freezes 25 ; life beat, 98 ; fever heat, 107. „ composed of water, 78*56; colouring matter, (Hematosin and Globulin,) 11*962. Albumen, 6*94 ; fatty matter, *43 ; fibrin, *356 ; oily matter, *227 ; albu- men combined with soda, *202; extractive matter, *192; portions of chlo- From the expansion of the glass tube. OF HEAT. 43 ride of sodium, potassium, carbonates, phosphates and sulphates of potash and soda altogether, *73 ; carbonates of lime and magnesia, phosphates of lime, magnesia and iron, and peroxide of iron, altogether, *142; loss in analyses, *258 ; total, 100. — M. Lecance. Sea water (salt 1, water 29), . . . freezes 28 boils 224° Milk freezes 30, ferments 100, yielding some alcohol. Ordinary milk contains — Water, Sugar, Butter, Cheese, Total, cons Woman’s . 87*98 6*50 3*55 1*52 *45 100 Ass’s . . 91*65 6*08 0*11 1*82 *34 100 Cow’s . . 87*02 4'77 3*13 4-48 -60 100 Henry Chevallier. Water freezes 32, boils 212'^, fixed thermometrical points measures per cent. Water in cooling from 212^ to 189*5 contracts 18 in 2000 , or *9 >> >> if IS 189*5 to 167 16*2 in ,, or *81 M >> if >» 167* to 144*5 „ 13*8 in ,, or *69 IS SI if if 144*5 to 122 11*5 in ,, or *575 ts if IS 122* to 99*5 „ 9*3 in „ or *465 Jf >> if if 90*5 to 77 7*1 in ,, or *355 if fj if if 77* to 54*5 „ 3*9 in „ or *195 if if 11 . . > > 54*5 to 32 0*2 in ,, or *001 Rumfordo Olive oil, freezes 36 Phosphorus burns slowly at 43, vividly at 122, boils at 554 Mean temp, of the earth’s surface 50 „ of our climate . 52 Vinous fermentation begins Acetous ,, Animal putrefaction from . Summer heat in this country 59, rapid at 77 77, ceases at 88 66 to 135 75 to 80 Heat in Great Exhibition, June 26, 1851, Floor, 85, Galleries, 95. Carbonic acid Tallow Animal heat Spermaceti . Sulphuret of carbon Wax, yellow Stearic acid (per Chandler) melts, 85 92 96 to 100 melts, 112 „ 116 „ 142, white 155 „ 158-167 44 SOURCES OF HEAT. Alcohol . . . boils, 173 Sodium . . . melts, 190 Bismuth 2, lead 1, tin 1 . „ 201 (^Rose^s metal) Steam from ordinary water, begins to form, 212 ,, sea water ,, 224 Sulphur Iodine Tin 1, Bismuth 1 Essential oils Steel (tempering) pale yellow Tin 2, Lead 1 (soft solder) Tin and Cadmum . Tin 1, Lead 3 (coarse solder) Bismuth Lead . . . Whale oil Iron, red heat in the dark . Linseed oil Nickel magnets lose their polarity Zinc Hydrogen Charcoal Antimony Common Bronze (100 copper, 10 tin) Brass Copper Silver (variously stated) Gold ,, Money (Gold 11, Copper 1) Steel Cast Iron, variously stated as Air Furnace melts, 218, boils, 570 „ 225, boils 347, burns 363 „ 289 boil, 320 temp. 330, deep blue, 580 melts, 360 „ 442 „ 480 „ 476 to 507 „ 594 to 612 boils, 630 . 635, in the light 980 640 630 melts, 680 to 773 burns, 800 „ 802 melts, 797, 812 temp. 1141 melts, 1652 „ 1869 „ 1996 „ 1832, 1873, 2233 „ 2016, 2182 „ 2150 „ 2372 to 2552 2732, 2786, 3479 3500 Sources of Heat, The chief sources of heat are the Sun, the Earth, Electri- city, Friction, Percussion, Compression, and Chemical Action. There is a difference between the rays of heat from the sun COMMUNICATION OF HEAT. 45 which passes through glass like light, whilst the rays of heat from a fire are arrested and absorbed by the glass, and only very slowly pass through it. The effect of the rays of the sun in extinguishing a common fire are also well known. Electric heat, like common heat, is also arrested by glass, which is accordingly employed as an insulate in electric expe- riments. What heat really is so much perplexes the closest investi- gators, that it may be submitted, as a question to be solved by electricians, whether there is a point under the ordinary or extraordinary combinations of heat and water as applied to generate steam, when electricity would he engendered and communicated to the water. If there is such a point, and electric and common heat are only different degrees of concen- tration of the same body, then the great difficulty regarding steam-boiler explosions would be more satisfactorily solved than has yet been done. Heat is communicated to other bodies in three ways, 1st. By direct contact, called Conduction, 2nd. By right lines, called Radiation, 3rd. By carrying, called Convection. Conduction. When two bodies of unequal temperature are placed in con- tact with each other, the hotter body communicates heat to the colder body until they become of equal temperature. The rapidity of this equalization depends upon the nature of the bodies themselves, as all bodies do not conduct heat alike, and are accordingly called good or bad conductors. Wood, for instance, is so bad a conductor of heat, that if a piece of it be set on fire at one end it can be held until the flame has reached the hand without the heat having been previously conducted by the fibres of the wood itself. Glass is also a bad conductor of heat. Fluids also conduct heat very slowly, mercury excepted. 46 CONDUCTION. Metals are good conductors, but vary in their power of doing so, as seen in the following tabular classification of their com- parative powers of conduction. Gold . . 1000 Tin . 303-9 Platina . . 381 Lead . 179-6 Silver . 973 Marble . 23-6 Copper . . 898-2 Porcelain . 12-2 Iron . 374*3 Fire Clay . 11-4 Zinc . 363 Water 9- The conducting power of metals may be experienced by holding the point of a pin in the flame of a candle, when the heat is rapidly conducted to the head until it cannot be held by the uncovered fingers. Atmospheric air and gases have been generally regarded as bad conductors of heat ; but recent investigators consider that the atmosphere conducts heat as rapidly as it does sound, but that their effects are rendered almost invisible from the small quantity of ponderable matter in the air. The conduction of heat through a body is by some re- garded as radiated, by others as communicated from particle to particle within the body, and the rapidity of communica- tion regulated by the density and molecular construction of the body. Radiation, When a hot body, such as a fire or a mass of metal, is sur- rounded by other bodies not in immediate contact, but placed at some distance from it, the heat from the hot body radiates from the centre in lines to the colder bodies, with a power in- versely as the square of the distance from the centre. The greatest effect is upwards, the least effect is horizontally to the surface. The surface of the bodies receiving heat exercises a marked effect on the quantity absorbed in a given time. It was shown by Leslie that a tin vessel filled with hot water RADIATION. 47 and covered over with lamp black possessed a radiating power = 100, but , Covered with scaling wax . ^ i \ 1 I ■ ■1 1 V ‘ ^ ; 95 33 writing paper . • i ' ^ A t:'/ 33 resin 96 3) 33 crown glass . 91 }} 33 china ink 88 33 red lead 80 33 plumbago or black lead 75 J5 33 isinglass 75 33 33 tarnished lead 45 33 33 scratched tin 22 •3 33 bright lead 19 33 33 mercury 20 33 33 polished iron 15 33 33 sheet tin 12 Here lamp black and white paper have nearly the same power, whilst China ink and black lead have much less. A thermometer is more affected by an equal amount of heat when coated with chalk than when coated with Indian ink, and a thermometer made with coloured spirits rises more, for equal heat, than an uncoloured one. For instance, painted bodies having a metallic surface from the paint radiate much more than the same bodies not painted. Hammered metallic bodies radiate slower than when less dense, as hammered silver has only a radiating power of 10, hut not hammered of 13*7. When the surface of each is scratched the radiating power is inversely affected, for the hammered is 18 and the cast only 11*3. This leads to the inference that radiation depends upon a thin film at the sur- face regulated by the density, for the increase of rough bur- nished silver is of that of polished hammered, while the cast rough decreases ^ from that of polished cast silver. The absorbing power of a body is usually reckoned as equal to its radiating power. 48 RADIATION. Colour was long held to alFect radiation, but that is now found untenable. It owed its probability to the observed effects of the heat of the sun in radiating most from black, less from blue, green, red, yellow, and white, in the order in which they stand, when acted upon by heat combined with light. Ab- sorption of ordinary heat without light depends, as has been seen, more upon the nature of the surface than of the colour. It was also generally supposed that there was some ratio between radiated and conducted heat ; but it is now ascertained that it only approximates at low but not at high temperatures, and that at 60 to 120 Cent, it is as 3 to 7, at 60 to 130 Cent, as 3 to 13, and at 60 to 240 Cent, as 3 to 21, whilst on the old law these numbers would have been 6, 9, 12, instead of 7, 13, 21. The properties of passing heat and light through bodies appear to have little relation, and Mellorie regards them as being inversely to each other. Thus blackened glass passes heat but scarcely any light, and wood passes neither. Of trans- parent bodies mineral salt passes 92 per cent, of heat, but alum only 12 per cent. Radiation has therefore been considered as equal in power but inversely to absorption, and that at the same temperature the radiating and absorbing power of bodies are equal. Radi- ation may be defined to depend upon the facility of decompo- sing the particles, but absorption upon the inability to reflect them back. Much of the comparative economy of steam boilers depends upon their absorbing power ; for no matter how ably the furnace performs its duty, if the heat given off from the fuel cannot be taken up as rapidly as it is produced, then of course economy ceases. The rapidity of production of heat in a locomotive furnace is not favourable for the entire absorp- tion of that heat : hence the advantage of the numerous thin metal tubes to divide and absorb the heat generated in the furnace. It is not the least merit in this class of boilers, that as the velocity increases so does the area of conduction or CONVECTION. 49 direct contact of the heat, whilst the area of radiation decreases in the same ratio. For as the draught upon the fire increases so does the length of the flame ; consequently not only the fire box, but also a greater or lesser portion of the thin tubes in immediate contact with that flame, absorb heat by conduction, and the remainder of the tubular surface absorbs it by radia- tion from the passing gases. Convection, Convection or carrying is the^power possessed by fluids of conveying heat acquired at one place to another place. In boilers the heat is thus transmitted amongst the w'ater. In the furnace the air carries the unabsorbed heat to the chimney. When the power of convection is much greater than the power of absorption, then the heat evolved during combustion is carried off without producing its proper effect. The greater therefore the absorbing power of any boiler, the greater will be its economy. In locomotive boilers at high ve- locities, this power of convection increases as the radiating surface decreases, and the loss of heat by convection is in pro- portion to the velocity of the escaping gases and the shorter distance passed over by them. In solid bodies heat travels from atom to atom, but in fluid bodies, the heated parts fly off and colder ones take their place until the heat has been diffused. It is only by convec- tion that air carries heat, for if its circulation be stopped it nearly ceases to carry heat. Glass also carries heat slowly, and it is estimated that a square foot of glass exposed on one side to the atmosphere will cool 1*279 cubic feet of air 1° per minute, when it is in contact with the glass, as seen in the condensation of the vapour in the air on it precisely as dew is formed on the grass. A cast-iron pipe 3 inches diameter, and metal I thick cooled down 1° in 1*21 min. with a black surface, In 1*25 mm. D 50 REFLECTING AND with an iron surface, and in 1*28 min. with a white painted one. Reflecting Power, The reflecting power of different bodies is generally esti- mated as being inversely as the radiating power, so that if brass reflects 100 parts of heat, silver would reflect 90, and with these others as they stand below. Brass . 100 Silver . 90 Tinfoil . . 85 Block tin . * . . . 80 Steel . 70 Lead . 60 Tin foil, softened by mercury . . 10 Glass ■ . . 10 Glass, coated with wax . 5 Speciflc Heat, The specific heat, or the comparative capacity of bodies of equal weight to receive heat, varies widely. Thus, if lib. of mercury at 32° be mixed with water at 62°, the temperature wdll become 61°, or if the mercury had been 62° and the water 32°, the common temperature would have been 33°, showing that the capacity of mercury for heat is about ~ of that of water. It may therefore be considered as the ratio of the heat in a given weight or volume to those of the standard body. Iron shows a specific heat of *113 or i that of water, and steam ’Sd?. Water is usually made the standard of comparison for ponderous bodies, and air for gaseous bodies. ’ The capacity of bodies for heat is also tested by the quantity of ice they will melt : thus, equal weights of iron and lead, heated to 100° would melt 1 1 grains by the iron, and only 3 grains by the lead, each falling to 95°. The same test applied to fuel has given the following results. SPECIFIC HEAT 51 1 lb. of good coal melts 90 lbs. of ice. ii coke 33 84 lbs. „ 33 wood 33 32 lbs. „ 33 wood charcoal 33 95 lbs. „ 33 peat 33 18 lbs. „ It may be mentioned here that it was on this plan that Dr. Arnott tested the quantity of heat passing from a common fire up the chimney, and by the quantities of ice melted he found it more than the whole heat radiated out into the room, which melted less ice than the heat carried up the chimney. The following is a table of a few specific heats. Table No. 11. SPECIFIC HEAT IH HIFFEEENT BODIES. Eegnault. D along. Iron •1137 •110 Hydrogen . . 3-2936 Copper •0951 '0949 W ater 1* Zinc •0955 •0927 Steam . . •847 Nickel •1086 •1035 Alcohol . •600 to -700 Cobalt . •1069 •1498 Ether •6600 Platinum •0324 •0314 Oil •520 Gold . •0324 •0298 Air . . . •2669 Sulphur . •2026 •1880 Nitrogen •2754 Carbon •2411 •25 Oxygen . . •2361 Phosphorus •1887 •385 Carbonic acid . •2210 Iodine •05412 •089 „ oxide •2884 Arsenic •0814 •081 Charcoal . . •2631 Lead •0314 •0293 Oil of turpen- Bismuth •0308 •0288 tine . . •426 Antimony •0507 •0507 Sulphuric acid. •333 Indian Tin •05623 •0514 Nitric acid •426 Mercury •0333 •0330 Iron at 212° . •110 Steel •118 „ 392° . •115 Brass . •094 „ 372° . •122 Glass •177 „ 662° . •126 Salt . •225 ,, carbonate of •1819 Marble . •205 Zinc ty •1712 The difference in the quantity of specific heat by different experimenters arises from the delicate nature of the experi- D 2 52 HEAT AND COMBUSTION. merits and tlie manner of performing them, in which the minutest error becomes magnified when generalized. The capacity for heat increases with the temperature, as seen in iron, and in cooling a greater amount of heat is given out in cooling down an equal number of degrees at a high than at a low temperature. To raise lib. of water from 32° to 212^ or 180° requires as much heat as would raise 3*72 lbs of air through the same range. Strictly it is as *2669 is to 1. Relative Heat, Specific heat is by equal weights of the compared bodies, hut relative heat is by equal volumes. Thus the specific heat of steam is only *847, but its relative heat is only 2 J 8 that of an equal volume of water, and would lose as much heat in one minute as the water would do in 228 minutes. Relative heat is therefore directly as its specific heat and volume. With gaseous bodies the specific heat is inversely as their specific gravity ; hence equal quantities of such gases contain an equal quantity of heat less their specific gravity. As the relative weights of equal volumes of gas are inversely as their specific gravity, equal volumes will have equal relative heats. When mechanically mixed, such as the oxygen and nitrogen of the air, or the heat and water in steam, though of dilferent densities, yet they have equal relative heat. When gases are chemically combined, they have a different relative heat above that of air, and each gas has its own relative heat, of which air is the unit of comparison. The relative heat of air to water is 0*2669, which multiplied into any aerial comparative exponent would give the comparison with water similarly to ponderous bodies. Combustion^ or the Production of Heat, Heat appears to be a compound derived from the union of a combustible with an incombustible, which supports or sup- Combustibles and incombustibles. 53 plies the constituent part necessary to complete combustion, and without which definite supply combustion is imperfect. This combination infers ditferent qualities of the two ingredi- ents in the compound of heat. Strictly, the process of com- bustion is complex, and only partially understood. As far as regards its ordinary operation in the steam-boiler fireplace, we will endeavour to convey a clear exposition of its more import- ant features. A coal for instance thrown on a fire evolves amongst others, the two principal combustibles of carbon and hydrogen, which uniting with the oxygen of the air — an incombustible yet a necessary supporter of a fire — produces heat and light at the same time. Simple as this may appear, its analysis is yet a complicated chemical problem. The chief agents operating in the furnace are carbon, hydrogen and oxygen, and their union in certain proportions produces other bodies, as water or steam, carbonic oxide, carbonic acid, besides others of less practical importance. Combustibles and hicombustibles. A combustible body is one whieh actually burns, such as carbon. An incombustible body is one that does not itself burn. A supporter of combustion is one that does not burn, but gives strength and support to one that does burn, such as oxygen, which supports carbon in producing heat. A common fire exhibits the union of the carbon of the fuel and the oxygen of the air. A gas light exhibits the union of carbon, hydrogen, and oxygen to produce both heat and light. In neither process is the oxygen burnt, but only the combusti- bles, carbon and hydrogen. In all ordinary circumstances oxy- gen is therefore an indispensable element of combustion, and its proper supply a question of the first importance to economy of fuel. For instance, if only 8 parts of oxygen are admitted for each 6 parts of carbon evolved from the fuel, the combus- tion is very imperfect, and much of the heat of the fuel 54 ELEMENTS OF COMBUSTION. passes off in combustible gases, of which carbonic oxide is the chief. If, however, 16 parts of oxygen are admitted to com- bine with 6 parts of carbon, the combustion is 70 per cent, better than the last, producing steam and carbonic acid as the products of perfect combustion. Under the ordinary pressure of the atmosphere, oxygen is the supporter, and carbon and hydrogen the combustibles, but in a vacuum, or under the in- tense action of the oxy-hydrogen blastpipe, invented by my friend Goldsworthy Gurney, Esq., and now attracting so much notice in the Crystal Palace — this natural order is re- versed, and oxygen becomes the combustible and carbon the supporter of combustion. The following are the usually received definitions of che- mical combination, mechanical mixture and the elements of combustion. Chemical Combinations, When two bodies unite to form a third body distinct from either of the combining bodies, this is called chemical union, as when carbon and oxygen unite to form heat, carbonic oxide or carbonic acid, or with hydrogen to form water. Mechanical Mixtures, A mechanical mixture is one where the bodies have been brought together, but each retains its original qualities, such as sand and water, or the oxygen and nitrogen of the air, or heat and water in steam, all of which can be readily separated and restored to their original state again. Atmosphere. This important body which surrounds us, and supplies the oxygen, or life of our breath, besides its other invaluable fea- tures, is a mechanical mixture of one-fifth part of oxygen and four-fifth parts of nitrogen, sometimes called azote. The latter dilutes the former, and renders it adapted to the consti- AIR AND OXYGEN. tution of man and the animal creation ; and but for this dilu- tion of the oxygen by the nitrogen, constituted as we are, life would be an accelerated but short course, similar to the bril- liance exhibited by a wax taper when plunged into a jar of oxygen on the lecture table. Oxygen is therefore the principal supporter of both life and combustion ; but the peculiar uses of nitrogen are only clearly understood as indispensable to vegetation. An ordinary iron furnace is estimated to require 310 tons of air in 24 hours, or as much as 20,000 men. That it is the oxygen which changes or supports ordinary combus- tion may be shown by covering an ordinary candle with a bell glass whose lower edge rests in water, to prevent a further supply of air inside the glass. As the enclosed oxygen is changed the flame grows less and less until it is extinguished, and the contents are found to be nitrogen apparently un- altered, hydrogen and carbonic acid. 100 cubic inches of air weigh 31 grains. Oxygen, This gas was discovered by Dr. Priestley in 1774, and is considered to be one of the most abundant bodies in nature. It is a permanent colourless transparent gas without smell, and I'll times heavier than air, and 100 cubic inches weigh 34*1 84 grains. It combines with many other bodies in a variety of ways, forming very distinctive compounds. For ordinary combustion and breathing it is supplied from the atmosphere, but for the lecture-room it can be readily obtained in several ways, one of which is by heating the chlorate of potash, and collecting the gas given off in a bladder or jar. If a taper with a single spark of fire left on its wick be placed in any jar of oxygen, it immediately burns forth with splendour, and iron when introduced is melted down in a shower of dazzling scintillations, forming oxide of iron. Ordinary rust is also oxide of iron formed from the slow combustion of atmospheric temperature, whilst the intense 56 NITROGEN. temperature of carbon and pure oxygen produce rapid com- bustion, and the smith’s forge is only another degree of the same process. Phosphorus introduced amongst oxygen pro- duces a volume of painfully brilliant light forming phosphoric acid. The oxy-hydrogen light, as invented by Mr. Gurney, im- proved by Mr. Beechy, and exhibited by Mr. Abraham of Li- verpool in the Great Exhibition, consists in bringing equivalent quantities of oxygen and hydrogen gases into a burner and ig- niting them, when they evolve vivid combustion and intense heat, melting all common metals with great ease. Lime, however, resists its fusive power, but evolves the most brilliant light then known, which is employed in the Polytechnic Institution for their microscopic views. Recently, however, a still more luminous light is produced by the actipn of electricity on two pieces of charcoal, and M. Lessel and Co. exhibit one of great illuminating power at the Crystal Palace, whose light when tried by the prism shows the solar spectrum rays of the light of the sun, viz., red, orange, yellow, green, blue, indigo, and violet. Nitrogen. This body neither supports life nor combustion. It is lighter than air, has no taste or smell, is little absorbed by water, and has no effect upon lime water. Its specific gravity is *972 that of air, or 100 cubic inches weigh 30*15 grains. Although nitrogen has some properties in common with carbonic acid, one of the products of perfect combustion, it has also dissimilar ones, besides being an elementary body, while carbonic acid is a compound of oxygen and carbon. Nitrogen is necessary to life. Carbonic acid is poisonous. Protoxide of nitrogen forms the well-known laughing gas, which produces such an exhilarating flow of spirits and muscular energy, by a few inhalations of it, and its specific gravity is 1*527 that of air, or 100 cubic inches = 47*37 grains. CARBON. 57 Carhon, This is a finely-divided pulverulent mineral body in its or- dinary state, forming the basis of most fuels, and found in many different forms ; as it is obtained by various processes — from oil lanips, as lamp black ; from coal, as coke ; and from wood, as charcoal. It is the mineral particles of carbon in a state of combustion which render flame luminous from either gas, oil, or candles. Tallow or wax candles are a compound of carbon, oxygen and hydrogen. The diamond is pure car- bon in a crystalline state, possessing the singular property of reflecting all the light which falls upon it at an angle of about 24°, whilst artificial gems only reflect half that light. The diamond is highly valued, and in much esteem as an article of dress, or to adorn an imperial crown. Amongst the many attractions of the National Exhibition, her gracious Majesty’s three specimens of pure carbon in the celebrated Koh-i-noor and two other diamonds, are none of the least. To the general reader the following partieulars of the Mountain of light,” (Koh-i-noor) may possess interest. The Koh-i-noor has no ordinary history, having frequently changed owners, either by the fortunes of war or intrigue, and is now little more than a third of its original weight, being reduced, by the unskilfulness of Hortense Berghere, a Venetian lapidary, from 800 to 279 carats. Its original value was estimated at 3^ millions ; it is now estimated at only half a million, for diamonds rapidly increase in value with size. It first received notice when belonging to the Mogul Princes, and was obtained by Nadir Shah when he plundered Delhi, to the extent, it is said, of 40,000,000^. On his assassination it dis- appeared for a time, until Ahmed Shah’s time, and it passed from his successor, Shah Soojah, to Bunjeet Singh, on whose death it remained at Lahore until it was taken by the British during the last Sikh war, and is now exhibited in Great 58 CARBONIC ACID. Britain’s Industrial Palace. It is not now the largest diamond known, although originally it was so, as that of the Rajah of Mattan in India weighs 367 carats, or 3 ounces troy. A few other celebrated pieces of crystallized carbon are, the Empress of Russia’s, weighing 193 carats, and valued at 90,000^., the Emperor of Austria’s, weighing 139 carats, valued at 100,000/., and the Orleans or Pitt diamond, weighing 136 carats, and valued at 164,000/. Such are the values of small pieces of carbon, as found in the diamond, but intrinsically, for national wealth, they will not bear an instant’s comparison with that form of carbon which composes from 60 to 90 per cent, of coals. The former is an absorber of wealth otherwise existing ; the latter is a producer of wealth throughout the world, and in this country forms the basis of our power and progress, without which the Crystal Palace had not been called into existence. Carbon also unites with iron to form steel, and with hydrogen to form the common street gas, called carburetted hydrogen gas. Analysts tell us that the diamond and its converse, lamp black, are both pure carbon ; and charcoal and coke are other well- known forms of carbon, obtained by burning them with a par- tial supply of air or oxygen. Coals are a compound of carbon, hydrogen, nitrogen and oxygen. Carbon is considered as the next most abundant body in nature to oxygen. In the furnace the carbon of the fuel unites with the oxygen of the air to produce heat. If the supply of air is correctly regulated there will be perfect combustion producing carbonic acid, but if the supply of air be deficient, combustion will be imperfect, and carbonic oxide produced. Carhonic Acid Gas. When air passes through a fire, this gas is formed by the combustion of 16 parts of oxygen and 6 parts of carbon. Its specific gravity is 1*523 that of air, and it forms 44 per cent CARBONIC Oxide and hydrogen. 59 of lime. It is fatal to life, as exemplified in the black hole of Calcutta, Avhen about 140 men died in one night by breath- ing the same air again and again until the oxygen in it had become this gas. It also extinguishes fire, as has been so ably shown this year by Mr. Gurney, forcing it into the burning Sauchie coal mine, and putting out a fire of about 26 acres area and 30 years duration. Carbonic Oxide, This is a colourless, transparent, combustible gas, which burns with a pale blue flame, as may be seen at times on opening a locomotive fire-box door. Its presence in a furnace is evidence of imperfect combustion, from a deficient supply of air, as it indicates that only 8 parts of oxygen instead of 16 parts have united with 6 parts of carbon, requiring as much more to produce complete combustion. Hydrogen, Hydrogen is the source of all common flame, although it extinguishes a light plunged into it, but in doing so takes fire itself and burns at the edge of the vessel, similar to its^ issuing from a gas burner, when it combines with the oxygen of the air and gives out a brilliant flame, but does not enter into the tube or burner where the air is not in contact to supply the necessary oxygen. It is the lightest known body in nature, being 1 6 times lighter, for equal volumes, than oxygen, and is a permanent, yet combustible gas, giving out much heat. It was discovered by Cavendish in 1766, and being 14^ times lighter than air, it is employed in baloons. In our gas establishments it is now distilled from coal in large quantities, and combined with carbon for illuminating streets, shops, and dwelling houses. It is not itself innoxious to life, but does not support it, and 60 HEAT OF COMBUSTION. when combined with sulphur, it becomes explosive, and too frequently produces the most lamentable results in our coal mines. By passing a current of steam through a hot iron tube partly filled with filings, hydrogen gas is given off, and bui;ns with a pale yellow flame. It also combines with oxygen to form water according to Watt’s composition of that body. But the recent experiments of Payne seem to indicate that water may be decomposed by negative electricity into hydro- gen, and by positive electricity into oxygen ; and by both poles being applied, both hydrogen and oxygen are produced from the water, as ordinarily decomposed. Comparative Heat of Carbon and Hydrogen, Dulong estimates that 1 lb. of hydrogen will give out about 4*707 times as much heat as 1 lb. of carbon. In ordinary combustion there is rarely found any provision made to effec- tually consume the hydrogen evolved in the furnace, so that it has been usual to take the quantity of carbon in any coals or coke as the index of their heating powers. If hydrogen gas come to be cheaply evolved, or furnaces arranged to partly consume what is evolved, the theoretical and practical duty of fuel would be proportionally increased. If a unit of heat be taken as the quantity which would raise 1 lb. of water 1° Fah., 1 lb. of carbon is valued as equal to 13268 such units, and 1 lb. of hydrogen as equal to 62470 units, or 4*7 to 1 of carbon. In ordinary coal fires of engines the air is only admitted by the fire grate, and after passing through the fire, is conse- quently unfitted to totally consume the hydrogen gas evolved, which may thus pass off as lost heat, and what portion may be consumed will scarcely balance the heat necessary to its production. Heat from Combustion, This is variously estimated by different authorities. Des- PROCES% OF COMBUSTION. G1 pretz gives the following values on lbs. of water raised 180° by 1 lb. of each fuel. Lbs. of water 1 lb. of from 32'’ to 2 Hydrogen heat . . 236-4 Olive oil 5^ . . 90 to 95 Ether 5) • . 80 Pure charcoal 5) • . . 78 Wood charcoal if . 75 Alcohol fi . . 67-5 Coals 99 • . 60 Baked wood 99 . . 36 Process of Combustion in a Furnace. For raising steam the process of combustion consists in evolving and completely consuming the combustible elements of either coal, coke, or other fuel employed, to produce heat, which may be divided into four different stages of the process : First stage. — Application of existing heat to evolve the constituent gases of the fuel. In coals this is princi- pally carburetted hydrogen. Second part. — Application or employment of existing heat to separate the carbon from the hydrogen. Third part. — Further employment of existing heat to increase the temperature of the two evolved combusti- bles, carbon and hydrogen, until they reach the heat necessary for combination with the oxygen of the air. If this heat is not obtained chemical union does not take place, and combustion is imperfect. Fourth and last part, — The union of the oxygen of the air, with the carbon and hydrogen of the furnace in their proper equivalents, when intense heat is generated by the exchange of the electrical heat in each, and light is also given off from the ignited carbon. Sir H. Davy estimated this heat as greater* than the white heat of metals. PROCESS OV Cy2 In the first three stages of combustion heat is absorbed by the fuel, and only in the last stage of the process is that absorption replaced with greatly increased effects. When the chemical atoms of heat are not united in their proper equivalents, then carbonic oxide, carburetted hydrogen and other combustible gases escape invisibly, with a corre- sponding loss of heat from the fuel. When the proper union takes place then only steam, carbonic acid and nitrogen escape, which, being the products of perfect combustion, are all incombustible, and also incapable of supporting combus- tion. The principal products therefore of perfect combustion are : Steam, invisible and incombustible. Carbonic acid, invisible and incombustible. The products of imperfect combustion are : Carbonic oxide, invisible but combustible. Smoke, partly invisible and partly incombustible. Steam is formed from the hydrogen gas given out by the coals combining with its equivalent of oxygen from the air, in the ratio of 2 volumes of hydrogen to 1 of oxygen, or by weight as 1 to 8, as already explained. Carbonic acid is formed from the carbon of the coals com- bining with its equivalent of oxygen from the air, in the pro- portion of 2 volumes of oxygen to 1 volume of carbon, or by weight, as 16 to 6. Carbonic oxide is formed from the carbonic acid first pro- duced, receiving another volume of carbon in passing through the fire, which last volume of carbon is unconsumed, and forms the combustible carbonic oxide, whilst carbonic acid, having had its carbon consumed, is incombustible. Smoke is formed from the hydrogen and carbon which have not received their respective equivalents of oxygen from the air, and thus pass off unconsumed. The colour of the smoke depends upon the carbon passing off in its dark pul- verized state, but the quantity of heat carried away is not , COMnUSTTON. (]3 dependent upon the carbon alone, but also upon the invisilde but combustible gases (hydrogen and carbonic oxide), so that whilst the colour may indicate the amount of carbon in the smoke, it does not indicate the amount of beat lost ; hence the smokeless locomotive may, and does unobservedly lose more heat in this way than is lost from the combustion of coals in stationary-engine furnaces. Besides the demands of the carbon for the oxygen admitted to the furnace, the hydrogen evolved also requires its equiva- lent, and could this be fairly carried out in the locomotive furnace ; the oxy-hydrogen light is sufficient evidence of the intense heat whieh would be obtained. But where there is no provision for the proper supply of oxygen to such gases it is evident that the hydrogen evolved must nearly all pass off un- consumed. The hydrogen requires one equivalent to produce steam, and the carbon another equivalent to produce carbonic acid. Along with these two equivalents of oxygen the air contains eight equivalents of nitrogen (of no known use in combustion), also passing through the furnace, consequently requiring 10 times as much air as there are gases to be consumed. When less than the proper quantity of air is supplied, hydrogen, from its greater affinity for oxygen than carbon, will take up its equivalent for steam, leaving the carbon to pass off partly unconsumed, as carbonic oxide. An excess of air is, however, as injurious by its tendency to lower the temperature of the evolved gases below the point where the chemical union takes place, and requires to be guarded against in the well- arranged and well-managed fire place. ' A practical and familiar instance of imperfect combustion is exhibited when a lamp smokes, and the unconsumed carbon is deposited in blacks” all round it. When the evolution of carbon is lessened by lowering the wick to meet the supply of oxygen, the carbon is all consumed and the smoke ceases. What takes place with a lamp also occurs in a furnace, so that 64 PROCESS OF the proper supply of air is a primary consideration, both as regards its quantity, and its mode of admission to a fire ; for both affect the economical results. In locomotive furnaces for coke the air is usually admitted through the fire grate, and before it passes through a thick body of red-hot fuel, the oxygen is either all absorbed or so dete- riorated, that it is incapable of combining with the hydrogen, which thus passes off unconsumed, and ma}^ be occasionally observed to ignite at the top of a locomotive chimney, when it obtains its equivalent of oxygen from the surrounding atmo- sphere. Such ignition of course only takes place when the steam is shut off, as its condensation saturates or cools the gases below the temperature of chemical union. The economical generation of heat is therefore a process entirely distinct from the use made of that heat afterwards, just as the generation of steam is an entirely different question from its employment in an engine. Combustion may be perfect, but absorption of heat by a boiler may he inferior, and consequently evaporation of water bear a low ratio to the fuel consumed. To arrange the con- struction of a boiler with rapidly absorbing materials is the principle aimed at by our best boiler-makers, to obtain in- creased evaporative power. The human body has been frequently compared to a furnace, and the process of digestion to combustion, and it is a correct description, for oxygen is the active agent in both processes. In placing animal food in a red-hot platinum crucible, its carbon unites with oxygen to form carbonic acid ; its hydrogen with oxygen to form water ; its nitrogen either escapes free, or unites with hydrogen to form ammonia, leaving behind only some salts partly soluble and partly insoluble in water. Now in the living animal frame these processes are in regular operation. The food is the fuel, evolving carbon and hydrogen, which, combining with the oxygen inhaled by the lungs from the HUMAN COMBUSTION. 65 air, is burnt, and the products of combustion, steam and carbonic acid — are exhaled from the lungs. As in the experi- ment with the enclosed candle, so in the human body, the nitrogen of the air appears to he inhaled and exhaled without apparent alteration. The nitrogen and soluble mine- ral portions of the food pass off as salts of ammonia in the urine, and the insoluble portions or clinkers ” of the food require, as is well known, especially to those suffering from dyspepsia, to be as regularly cleared off as do the residue from the fire-grate. Sir H. Davy found that he required for respiration during 24 hours, 45,504 cubic inches, or 15,751 grains of oxygen, which produced 31,680 cubic inches, or 17,811 grains of car- bonic acid, of which 4853 grains were carbon. Since oxygen is only i of the air, the volume of air inhaled would be 45,504 X 5 = 227,520 cubic inches in 24 hours. The mean carbon issuing from the lungs of an ordinary-sized man is about 130 grains per hour, or rather more than 7 ounces daily, besides what passes off by cutaneous perspiration. In a state of repose, however, Savaser found that the consumption of oxygen was only that of a state of activity : hence sleep is known to be tired nature’s sweet restorer,” by its then allow- ing the human furnace a little rest ; for it is a law, that rapid combustion is equally fatal to the iron and to the vital furnace. The average quantity of air inhaled at once by a man is about 20 cubic inches, and as one fifth of it again leaves the lungs in a poisonous state (carbonic acid) it vitiates any confined atmosphere unless ventilation steps in to prevent injurious con- sequences more or less rapid — as the supply of air may be more or less imperfect. The animal heat of combustion is about 98'^ Fah., and is of course slow compared to an iron furnace of 3479° Fah. ; still both processes are chemically alike, and pure air is as needful a supply to the human furnace as it is an indispensable one to the locomotive furnace. ANIMAL COMBUSTION. 66 The following table of the temperature of combustion in man and other living species may be instructive. Table No. 12. HEAT OF COMBUSTION IN THE LIVING FURNACE. Class. Temp, of Atmos. Fah. Temp, of Animal. Fah. Class. Temp, of Atmos. Fah. Temp, of Animal. Fah. Man Various. 98 Crow 67 104 Monkey 86 102 Frog . . 76 77 Hare 80 100 Green Serpent 814 884 Tiger . . 80 100 Brown ditto . 824 844 Dog 80 102 Brown Adder 824 90 Cat; . . . 77 102 Shark . 74 77 Horse . 79 101 Trout . . 554 574 Ox . 79 102 Flying Fish . 774 77f Kite . . 80 100 Oyster . . 81 81 Sparrow 80 108 Lobster 794 79 Pigeon 78 109 Crab . . 72 72 Hen . 78 110 Beetle . 76 77 Goose . . 78 106 Glow-worm . 72 734 Drake . 78 no Wasp . 744 76 The temperature of the animal body appears to be regulated by its own internal combustion without reference to the sur- rounding medium. For instance, man is found to possess the same heat under all climes and temperatures supportable by the human body. It is estimated that the heat given off by the human body in 24 hours would raise 63 lbs. of water from the freezing to the boiling point, yet the carbon thrown off from the lungs is estimated as only equal to heat 364 lbs. of water, through the same range. The difference is supposed to be due to the action of the muscles and the nerves. Application of Heat to produce Steam or Evaporation. The comparative effect of heat to produce steam in a boiler depends upon the ratio of the absorbing and transmitting power to the velocity of the escaping products of combustion. EVAPORATION. G7 For if the velocity be greater than the absorption and trans- mission of the passing heat to the water, then there will be a corresponding loss of heat. In the locomotive boiler with a rapidly escaping current only from iV to tV of the absorbing surface is by direct contact at ordinary speeds of the engine, and the remainder at right angles to the escaping current of heat. At high velocities the surface of contact will be in- creased to about i or a, whilst the velocity of the escaping gases will be also increased, over a decreased length of tubes. Therefore as the velocity is increased the economy of fuel is deereased, from the failure of the absorbing and transmit- ting power of the boilers to convey more heat in less time to the water. The comparative heat transmitted by conduction, radiation, and convection may be tested by alternately placing a thermo- meter in contact with the flame of a candle, next by its side, then over the top of the flame, and noting the temperature at each of the three positions. Or if the hand be cautiously substituted where a thermometer may not be convenient, the respective differences will be sensibly indicated, and give a clear idea of the heat lost by convection, when its velocity is considerable, and the absorbing space limited. In this re- spect Stephenson’s and England’s long boilers have an evident advantage over shorter boilers, where the diameters of the tubes do not offer sensible obstruction, for the largest portion of locomotive heating surface is on the worst or radiatory portions, at slow velocities, but decreasing as the increase of velocity extends the flames through the tubes. The experi- ments made by Mr. G. Stephenson, many years ago, showing the comparative evaporative ratio between the fire box and tubes of an engine at rest, as 3 to 1, would scarcely apply to an engine at very high speeds, since the relative conducting or radiating surfaces are not uniform, but vary with the velo- city of the engine and heating power of the fuel. With a 68 THEORIES OF HEAT. low velocity these surfaces might be more uniform, if the tlame acted only on the fire-box. The economical evaporation of water into steam depends therefore, first, upon perfect combustion ; and, secondly, upon the absorbing and transmitting power of the boiler. Where these powers are equal, the effects would be in the ratio of the surfaces of conducted and radiated heat, but where unequal in the ratio of their transmitting power only. Careful management of the fire to prevent air holes” burning through in places, a due regard to the air-admission spaces being uniform, and a steady regular supply of fuel, have con- siderable effects upon the economical results from any boiler. A clear level fire, kept fed by regular-sized pieces of fuel, and the fire-grate kept free from clinkers, all contribute to eco- nomy, and should be practised. To aid the fireman or driver in their duties, as well as for the higher objects of research, there should be in every locomotive boiler one glass pane in the fire door, and one in the smoke-box door, that both the fire and the state of the escaping heat might be seen, without opening either door, until such was really necessary. The chilly effect of opening the fire door in checking the pro- duction of steam is w'ell known, and might be so far avoided whilst the experienced eye would soon detect whether combus- tion was or was not perfect, and act accordingly. There is no practical difficulty in doing so, for both in this country and in America it has been done by our best experimenters, and, of course, could be done in daily practice with good re- sults. A good self-acting feeder of fuel is desirable. Theories of Heat, However well known may be the effects of heat, or the sen- sation it produces — whilst exhibiting its gentle docility in sup- plying the many wants of man, its destructive powers in conflagrations, explosion, or artillery ; its potent sublimity in CALORIFIC THEORY OF HEAT. C9 the thunder-storm ; its awe-inspiring force in the heaving earthquake ; its formidable grandeur when issuing from the volcanic safety-valves of the great globular boiler on which we live ; and the immense magnitude of its former operation in forming the shell of that boiler, all proving its power and in- fluence in creation — its real nature remains a matter of doubt, for its subtilty and extensive range of action have as yet de- feated definite analysis. This may appear singular to those who have only regarded heat as a common-place agent, since it is found still determinable at 480^ below Fab. zero, whilst the sun and electricity attest its concentrated energies. This intense heat and light are strikingly exemplified in the Great Exhibition, as already referred to. However, as cor- rectly observed by a recent investigator of its phenomena,* Every one knows the sensation of heat, though it may be difficult to describe it.” The following is a brief outline of the prevailing theories of its nature, followed by a few practical remarks on them. There are two theories of heat which more particularly engage attention, with a third, derived from the others. The prevailing one is that heat is a fluid of so subtle a nature as to preclude any direct investigation of its nature, which fluid is called caloric. The next theory is, that heat is not a material fluid, but is the effect of motion, and its intensity regulated by the momentum of the atoms in motion. The third theory is that heat is the motion of an elastic fluid universally diffused. Calorific Theory of Heat, This theory assumes that heat is a material fluid called caloric, which is communicated from one body to another by conduction, radiation, and convection. This theory is also accompanied by the doctrine of latent heat, to account for the heat contained in any body not Herapath. 70 LATENT, MOTION, AND measurable by the thermometer, and therefore difficult to analyze as a property of a material body. Considering the prominence which the doctrine of latent heat has long borne in reference to steam, it will be necessary to fully explain it. Latent Heat, Latent or hidden heat is that heat which is not measurable by a thermometer. For example, the temperature of ice is 32°, but it requires 140° of heat to convert that ice into w^ater again, which is called the latent heat of ice, because the 140° are not indicated by the thermometer. Water kept quite still has been cooled to 5°, yet retained its liquidity, but on motion being given to it, a great portion of it suddenly became ice at the increased temperature of 32°. The difference of 27° is called the latent heat of water at 5°. Ai 212^^ water begins to pass off into steam, but it requires the same amount of heat to be continued nearly six times as long as raised the water to 212^ to convert it all into steam, which is thus called its latent heat. Taking the temperature of water as 52*^ we have 212^ — 52 = 160^ of heat added to the water to raise it to the boiling point, and 160 X 6 = 960^ usually reckoned as 10 00^^ for the latent heat of steam under the pressure of the atmosphere, but strictly 965*7'^. Regnault found, from an able series of experiments, from 1 up to 13*6 atmospheres, the total heat of steam increase from 1170^ up to 1230^ Fahr., while the diffused heat decreased from 973^ to 878^. The Franklin Institute found the diffused or latent heat of steam of 212^ to 215^ tempera- ture from 995*3 to 1038*5^. Motion Theory of Heat. This theory is, that heat is an effect measured by the motion of particles having powder to communicate that motion to FLUID THEORIES OF HEAT. 71 other particles or to other bodies. If the motion he greater in one part than in another part of the same body, the heat will be unequal, but with a tendency to equalize the tem- perature throughout the mass. The power to heat would be as the temperature directly and the number of particles in mo- tion conjointly. By bringing a thermometer in contact with a body, the motion would be communicated to the mercury, and the amount of motion be read off in the scale of parts as usual. Atoms or particles of bodies moving towards each other would unite, forming a smaller number of particles with more heat for each, but if the motion tended to separate the atoms, the temperature would decrease with the decreased momentum. When water becomes ice, the particles combine, and the motion or temperature remains uniform, or when water be- comes steam the atoms are divided with a less temperature for each, but an increased aggregate temperature. There is, therefore, a growing disposition to regard heat as an effect similar to light, heat, space, or electricity, and that this effect arises from motion, Theory of Heat as a Fluid in Motion, This is merely a combination of the leading features of the calorific and motion theories, evidently based on the idea so natural to all finite minds, that by some finite agent the effect of heat might be accomplished. This theory regards heat as a fluid in vibratory motion capable of producing all the known results or phenomena attending the evolution of heat. It differs from the motion theory by regarding the fluid as material, but agrees with it in all other points as to the effect of motion in developing heat. The remarks, therefore, on the motion theory will apply to this one, excepting the ma- teriality of the agent, which is the difficulty required to be solved — whether heat is or is not a material body. 72 REMARKS ON HEAT. Remarks on Theories of Heat, To an ordinary observer there is a difficulty in reconciling the doctrine of latent heat with the simple laws of nature, yet it is no ordinary matter to differ from the many able men who have supported this doctrine. A conviction however that as regards steam it is untenable, leads to the following re- marks, being submitted with every deference to those who take an opposite view. The usual definition of latent” is hidden^ and that the heat in any body which is not measurable by a thermometer is latent heat. Now it may be observed that the heat-pro- ducing properties of bodies differ greatly, and are quite dis- tinct from their sensible heat. Thus stones from the quarry and coals from the mine, have little difference of thermometric heat, but on combination with oxygen their power of genera- ting heat is very different. If this property of bodies evolv- ing either heat or other body peculiar to their atomic forma- tion be considered as a latent or hidden power, it should follow by parity of reasoning that, the effects of sound, or light pro- duced by a change of circumstances from any other body w^ould be the latent power of such body. For example, a piece of artillery fired along a narrow street, produces a sound ac- companied by a motion of the air sufficient to break the glass in closed windows, but not in open ones, which leave a passage for that motion to exert its force on the more resisting walls. Minute calculations are given to inform us that the harmo- nious sounds of musical instruments are the effects of definite numbers of vibrations in a second of time, that the range of these vibrations for vocal music are for a male voice from 384 to 1266, and for a female voice from 1152 to 3240 ; that the highest note in music (five octaves above the middle C of the piano) is due to 8192 vibrations in a second, the next C 4096, the third C 2048, and so on to 16 vibrations, as the lowest AND SOUND. 73 note in music. The sharpness of the sound being due to the number of times the vibrations strike the air in a second. Fig No. 8, shows the theory of the vibration of a violin Fig. No. 8. string, A B, which is estimated to produce 240 vibrations, if touched by the finger at a certain distance from the bow line ; but if the string is pressed one half nearer to that line the sound is an octave higher, and the number of vibrations doubled, or 480 per second. The motion is, however, supposed not to be in uniform lines passing and repassing the centre lines, but more like the curved outline at C, as in Fig. No. 8. Fig. No. 9, shows the theory of the motion produced by Fig. No. 9. a bell, every vibration sending a spherical wave in every di- rection, resembling those circular ones on the surface of a smooth sheet of water when a pebble is thrown in. The more regular these waves the more musical the sound, whilst a series of irregular weaves produce a noise, but not a musical sound. A shrill whistle is due to several thousand vibrations in a minute.* Now, if sound be the effect of motion, and the variation of * Tomlinson’s Rudimentary Pneumatics. E 74 DIFFUSION OF HEAT sounds results from the number, momentum, or delicacy of these motions, heat may be equally the effect of motion, and its quantity due to the same changes of that motion as sound. For the animating tones produced by the accomplished per- former from a pianoforte, organ, or violin are equally hidden or latent, before being evoked by the impressive touch of the skilful artist, as is the heating power of fuel before ignition calls it forth. It seems, therefore, more in accordance with the simple laws of nature, to regard heat and sound as both phenomena called forth by motion, and amenable to the same general law. The power required to produce the motion of sound, is fairly represented by the force of heat required to give a higher degree of motion or temperature, so that the power of touch, or of mechanical agency in musical instruments, has its equiva- lent in the quantity of heat requisite to produce certain changes of temperature in given bodies, and will be measured by the resistance to greater motion of the particular body. It is usually advanced as a proof of the latent heat of steam that no additional heat imparted to the water increases its temperature beyond that due to the pressure on its surface, whilst six times the heat added to boil it is required to make that water into steam of the same temperature as itself. This, however, can easily be shown to be a good example of the law of equal diffusion by a very simple experiment. Let the glass phial B, Fig. No. 10, re- present a boiler filled with water to W, and placed over the flame of the candle C. At first there is no visible circulation in the water, hut it soon begins, and con- tinues to increase until small globules are observed to form at the bottom from some of the descending atoms of water, and as soon as formed dart off in an irregular zigzag ascent to the surface, retaining Water Boiling. IN STEAM. 75 their spherical form. The circulation increases until ebullition commences, and larger and more numerous globules are formed, crossing each other’s paths in their ascent to the top, where they expand into steam nearly 1700 times more voluminous than the water enclosing the globule. In the figure only two of these atoms of water, a, a, a, «, are represented, to make the process more obvious. The questions then are, what are these globules ? and, why are they in such haste to escape from the water ? The reply which naturally occurs is, that these globules are ascending atoms of heat instantly caught up and surrounded by their equivalents of water, forming steam of a specific gravity about 1300 times lighter than the water, and about 1*6 times lighter than the air pressing on the water ; hence their hurried irre- gular ascent is due to their less specific gravity struggling against the friction of the resisting water to their escape from confinement. These zigzag ascents of the little globules of steam bear some resemblance to the path of the forked light- ning darting through the atmosphere, and since the friction of condensing steam issuing through small orifices is abundantly proved by Armstrong’s hydro-electric boiler to produce vast quantities of electricity, is it impossible that the friction of these small globules through the water may not also evolve elec- tricity ? Armstrong’ s electric boiler artificially divides the con- densing steam to produce friction ; boiling naturally divides the water into its equivalent atoms, of separate ascent, pro- ducing a vast amount of frictional resistance to the escape of the atom of heat and its surrounding film of water. Instead therefore of the heat remaining in the water, it is evident that as soon as the water reaches the temperature of combination for steam, the atoms of heat which penetrate the boiler are separately surrounded and carried out of the water altogether, to be diffused amongst the steam, but are neither lost nor hidden. For if it only requires six atoms of heat to maintain an equal E 2 76 DIFFUSION OF HEAT temperature in 1/00 spaces of steam, as one atom of heat did over one space of water, we have = 283 as the relative 6 diffusion and activity of the heat in its new field. Since condensation recalls both the heat and water to their original spaces again, it proves their diffusion, for it could not be expected that the quantity of heat which would raise the temperature of one room 10°, would equally raise the temper- ature of 1700 equal-sized rooms ; yet such appears to be the inference drawn by those who denominate the diffused heat of steam latent or hidden heat, and its concentration as sensible heat. It will be seen, therefore, that it was a badly selected expression to call diffused heat latent or hidden, a description which is not applicable to the heat of steam. We do not usually call the heat of the air latent, yet it is in the ratio of the density of the air, as is familiar to all who have had experience with air pumps. For increasing density raises the heat, as when phosphorus is ignited by the increased heat of the air compressed in a small syringe. On expanding cooled air it rapidly absorbs heat from surrounding objects until an equilibrium of temperature is restored. Professor Smith, the Astronomer Royal of Scotland, has fully discussed these properties in an able paper on the cooling of air in Indian houses, and refers to the following tables of the heat of dif- fused and compressed air by Mr. Petrie, as entitled to con- fidence. Besides showing the effects of diffused and concen- trated heat in a given volume of the atmosphere, they will be useful for reference. Table 'No. 13, shows 508° — 60° = 448° below zero as the extreme ascertained cold, and 457’2 — 60 = 397*2 below zero as the temperature of air expanded without receiving any ad- ditional heat to 1000 times its original volume. Table No. 14 shows 4572° + 60 = 4632° as the heat of air compressed to its original volume. IN AIR. 77 Table No . 13 . DECREASE OF THE MEASURABLE HEAT IN AIR BY DIFFUSION. A given quantity of air e.jpanded to vols. Decrease of temperature from 60° Fah. A given quantity of air expanded to vols. Decrease in temperature from 60° Fah. 0-000 508-0 2 * 1048 1000 457-2 1-9 97-9 500 444 - 1-8 90-4 200 421 - 1-7 82-3 ’ 100 398 - 1-6 73-7 50 370 - 1-5 64-2 20 320-8 1-4 53-9 10 272-9 1-3 42-5 5 210-9 1-2 30 - 8 155-2 1-1 15-9 2-5 133-7 1-0 0-0 Table No. 14. INCREASE OF THE MEASURABLE HEAT IN AIR BY CONCENTRATION. A given volume Increase of A given volume Increase of of air compressed temperature of air compressed temperature to vols. above 60^ Fah. to vols. above 60° Fah. 09 17-1 0-1 586-4 0-8 39-1 0-05 870-9 0-7 64-2 0-02 1363-5 0-6 94-3 0-01 1850-1 0-5 132 - 0-005 2462-8 0-4 181-5 0-002 3524-0 0-3 251 - 0-001 4572-0 0-2 360-7 0-000 To apply these tables to any other initial temperature than 60 ^ add sis to the tabular number for higher, and subtract the same for every degree of lower initial temperature. There has been and still continues to he considerable dis- crepencies between the quantities given of diffused heat by various Investigators. Even the latest and most elaborate experiments of Regnault and the Franklin Institute differ in 78 HEAT TO MOVE ICE INTO WATER their exponents of that quantity. The following are a few of these discrepancies. Table No. 15. DIFFUSED HEAT OF STEAM BY DIFFERENT AUTHORITIES. Fall. Watt . . . 950 Black . . . . 800 Southern . . . 945 Rumford . . .1021 Ure . . . . 888 Fah. Thompson . . . 1016 Clement . . . 990 Painbow . . .958 Regnault . 880 to 973 Franklin Institute 996 to 1035 The smallness of the quantities operated upon, and the de- licacy of the operation itself render the slightest variation much magnified when applied to larger quantities. Their ge- neral approximation is however sufficiently near for all prac- tical purposes, and for facility in calculation, 1000° is usually taken as the diffused heat of steam of atmospheric pressure, and 212° as the boiling point, or a total heat of 1212° Fah. Now, according to the doctrine that the latent heat diminishes as the sensible heat increases, steam at 400° temperature would only have 812° latent heat, whilst steam of the tempe- rature of 1212° would have none, but instead of proving that the heat is latent, it proves only different stages of diffusion and concentration. Regnault’ s experiments show that whilst the total heat of steam is not uniform, but increasing, the diffused heat becomes less and less in quantity as the spaces occupied by a given weight of steam decreases. For as the pressure is increased the extent of motion of a given quantity is decreased, from the diminished volume of steam, so that whether at high or low pressures the temperature of an atom of heat will be inversely as the space it occupies, but not hidden. In cooling water to the unnatural liquid temperature of 5° its sudden release from that unnatural state produces exces- sive motion, developing 27° of heat as its measure of re- storative force, which in obedience to the general laws of na- ture is comparatively arrested at 32°. Now', agreeably to the laws of motion the friction of a body at rest is much greater AND WATER INTO STEAM. 79 than that of the same body in motion, hence the comparative rest of water in ice requires a force of 140° of heat to give it the motion of fluidity ; and the comparative rest of fluid water requires a force of 1000° of heat to give it the motion of steam. The heat therefore which moves the ice into water and the water into steam is the power externally applied to produce higher degrees of motion, and that motion will be the measure of the force so applied, just as the intensity of sound is measured by the musical scale from the number or force of the vibration of motion, as already referred to. Generally as an effect of motion heat will be measured by the power of the particles in motion to propagate and com- municate it to other particles. Unequal motion in any parts of a body would produce unequal temperature, tending how- ever towards an equality of temperature. The power to heat a body would be as the temperature directly, and the number of atoms in motion conjointly, which would be communicated to a thermometer in contact with it, and be read off in the usual manner. Atoms moving towards each other would unite to form a lesser number, with a greater amount of heat for each, or, if the motion tended to separate the atoms, they would be more numerous, but with less temperature for each separate atom. Thus we see the atoms combine, and uniform motion of 32° is obtained. When water becomes steam the atoms are separated with a less temperature for each, but an increasing aggregate temperature. For equal weights the heat of water would therefore exceed that of ice, and of steam that of water, as they are known to be by experiment. It is further evident, that thermometers only measure the quantity of heat which is communicated to them, but not the space over which heat may be expanded, nor the aggre- gate heat contained in such space. In a large factory where a number of machines are put in motion by one engine, the aggregate pow-er of that engine would not be indicated by the power required to move one machine, but by that power 80 THE TERM LATENT HEAT ” UNTENABLE. multiplied by the number of machines, and other resistances. Neither does a thermometer indicate the aggregate heat in any given space, as that depends upon both the capacity and. temperature combined. It is therefore difficult to realize the idea that diffused heat can be hidden heat, and some better term of expression than latent heat should be employed, if diffused” be not all that is necessary. The application of the term latent to the undeveloped pro- perties of bodies is we think equally untenable as it is to steam, and more appropriate terms should be employed if they are not sufficiently conveyed to the mind by their cus- tomary names, of air, gas, coals, water, ice, or stones. In- deed, it is satisfactory to observe the growing tendency to simplify scientific nomenclature, and the readiness with which it then passes into ordinary use, where the scientific name is most simple and expressive. Dalton found that 1 lb. of hydrogen and 8 lbs. of oxygen burnt in a close vessel produced 9 lbs. of water, and gave out as much heat as melted 320 lbs. of ice, or 35|^lbs. of ice for each lb. of the gases ; but 1 lb. of steam only melted 8*35 lbs. of ice, or less than one fourth the quantity melted by the equivalent weight of the gases. Now the thermometer does not indicate this vast difference, neither can it be the heat in the gas, since in the presence of intense cold it remains very little diminished in volume, whilst steam with very limited cold is condensed to water again. The heating power of gases is therefore like that of coals or coke, a property duly evolved under favourable combination. The light which these bodies give out may equally be designated latent, and dark- ness be only latent light. The sound they emit in giving forth heat and light may be equally latent. The chemical affinity, in short all the peculiar properties of bodies would thus be latent until we should cease to call them by their customary names, and only see before our eyes a mass of latents. For example, Mr. Staite has shown that heat, light, electricity, magnetism, motion and chemical affinity are all MANUFACTURE OF COKE. 81 produced in one line in the voltaic pole, where the battery re- presents motion and affinity; electricity in the deflection of the needle ; electro-magnetism in the helex: and heat and light in the ignition of the wire in irridium lamps placed in different parts of the circuit. There is now a growing tendency to consider heat, light, electricity, and sound as phenomena of nature, intimately asso- ciated with each other, and amenable to the same general laws. To draw general attention to the important nature of the composition of steam these remarks on the theories of heat have been made, and those who desire to extend their infor- mation on these points, will find them ably and scientifically investigated in Herepath’s Treatise on Mathematical Physics, where the motive theory of heat is elaborately supported. COKE. Since railway acts prohibit the use of smoke from locomo- tives, coals can only be sparingly used, and coke is generally employed in generating steam. Important as is this portion of locomotive expenditure, it appears to have received compara- tively little attention, for the ratios of quantity and heating power of coke to the coals from which it is made are much the same in 1851as they werefound to be by Smeaton nearly 130 years ago. Had no more progress been made in making and using steam than has taken place with coke, the success of railways would have been endangered by a continuance of the coke expenditure of 1831-2-3. In the Report on Coals for the Navy, Sir H. He la Beche and Dr. Lyon Playfair state, The whole sys- tem of manufacturing coke is at present imperfect,” and con- demn the management which allows some of the valuable pro- ducts from the ovens to be lost ; stating, as one instance of such loss, that for every 100 tons of coke made, about 6 tons of sulphate of ammonia, worth about ^13 per ton., could be col- lected and sold. To stimulate such economy they give the follow- ing ratios of ammoniacal products in the respective coals named. E 3 82 SULPHATE OF AMMONIA IN COALS. Table No. 16. AMMONIACAL PRODUCTS IN COALS. Name or Locality of Coal. Amount of Ammonia cor- responding to the Nitrogen con- tained in Coal. Amount of Sul- phate of Ammonia corresponding to the Nitrogen con- tained in coal. 0-497 1-932 1 0-225 0-990 1-590 6-175 1-238 4-808 1-586 6-741 1-299 5-044 0-218 0-848 Trace . . 1-76 6-835 1-808 7-340 1-299 5-044 1-347 5-232 1-919 7-448 1-675 6-505 1-639 6-364 1-748 . 6-788 2-622 10-182 1-554 6-033 1-785 6-930 1-214 0-471 Trace . . 1-712 6-647 1-372 5-327 1-639 6-364 2-234 8-674 1-477 9-617 0-279 1-084 0-777 3-017 0-977 3-771 1 132 4-620 0-813 3-158 2-040 7-920 Trace . . 0-983 3-818 Graigola . . . . Anthracite 'Aubrey, Anthracite Oldcastle Fiery Vein Ward’s Fiery Vein . Binea Llangenock Pentripoth Pentrefellin Powell’s Duifryn Mynydd Newydd Three-quarter Rock Vein Cwm Frood Rock Vein Cwm Nanty Gros Resolven Pontypool Bedwas . Ebbw Vale Porthmawr Rock Vein Coleshill . Dalkeith Jewel Seam Dalkeith Coronation Wallsend Elgin Fordel Splint . Grangemouth . Broomhiil Park End, Lydney Slievardagh (Irish) Formosa Island Borneo (Labuan kind) „ 3 feet seam „ 11 Wylam’s Patent Fuel Warlich’s „ Bell’s HARD AND SOFT COKE. 83 Besides these products there are also much heat and much hydrogen gas evolved during coking, which are seldom turned to any profitable account. Of late years several iron works employ the escaping gases from their furnaces with economical results, and at Dundyayvari Iron Works Mr. Budd states the saving to be at least 8 per cent. In cooling coke in the ovens there is also a considerable quantity of pure hydrogen produced from the decomposition of the water by the intense heat of the oven. It is at least worth a trial to determine the commercial value of collecting such products of the coke furnace, for what iron companies do railway companies could also do, and im- prove upon. The best process of manufacturing coke is still also an open question, some engineers preferring hard., others soft burnt coke, but the preponderance of numbers is in favour of the hard coke. Our observations tend to a different result, and to induce more attention to the manufacture of coke, the following remarks are submitted, accompanied by an abstract of the three valuable reports by Sir H. De La Beche and Dr. Lyon Playfair, on coals for the steam navy. The comparative term hard is understood to apply to coke from which all volatile matters have been expelled, and the term soft to refer to coke, in which a portion of these gases still remain. They apply equally to the same vertical piece of coke in the oven as to different processes of coking. The upper part would be comparatively hard, and further heat would have little to expel from it, whilst the lower part near the bed of the oven would be softer, and evolve a gaseous flame, by being exposed to further heat. In the Crystal Palace may be seen some beautiful speci- mens of hard coke, clean, silverydooking columnar pieces. At the base of these same pieces may be observed a darker look- ing portion, of less pleasing appearance than the top portion. This darker or comparatively softer part we regard as the most economical generator of steam in locomotive furnaces. 84 HYDROGEN VALUABLE IN COKE. arising from its still retaining a portion of the original gases in the coals. That hydrogen gas is more valuable in gene- rating steam than has usually been estimated, will be shown from practical examples with coals at the Par Consols mine, where they water their open burning coals to give intensity of heat in the furnace. Many of the best locomotive drivers ivater their coke to make it last longer and a recent patent in America is for employing steam properly distributed over the fire to promote economy of fuel. In each case it only introduces water in a finely divided state into an intensely hot fire, which decomposes it into its equivalent of hydro- gen and oxygen, and thus aids the evaporative powers of the fuel. From the coking property of some coals, water could not be beneficially used with them for steaming, since it would increase the tendency to coke, and retard the generation of steam by presenting to the boiler a fire surface compara- tively cold to that presented by the glowing intensity of open burning coals. This difference may be observed in a common house fire, when the poker is required to break the surface to obtain greater heat, whilst with other coals no such coking occurs, or ‘^pokering” the fire is required. The blacksmith’s forge is an every-day instance of wetted coals producing a very superior fire to coals in their ordinary state where intensity of heat is required in the centre of the fire, and not to radiate externally against a boiler or other object. Whatever evapo- rative benefit may be derived from such introduction of water will arise, it is evident, from the gases evolved, and shows how very desirable it is that, as far as practical, coking should aim at retaining and not expelling such gases. We are aware that it is usually held that the portion of water in coals, varying from 1 to 2 per cent., and that absorbed by coke, varying from 1 to 7 per cent, is not only a loss of weight, but also requires part of the remaining fuel to eva- porate such water. That it w^ould be injudicious to purchase wet fuel — also that such wetted fuel might sensibly retard PEAT TRIED IN LOCOMOTIVES. 85 tlie ligliting of a fire, is evident ; but it is also evident that if a small per-centage of water can be converted into hydrogen and oxygen, they will be more valuable than an equal weight of either coals or coke ; for in coke they would partly re- supply the gases expelled during the process of making, and add to those in coals, thus fairly accounting for the benefit said to be obtained in practice. Unless urged by a strong draught, nearly all the forms of pure carbon burn badly. The diamond long resisted the ac- tion of heat until Lavoisier succeeded in fusing it, and showed it to be pure carbon. Coke also requires a strong draught to promote its combus- tion. Lamp black in certain states ignites spontaneously in casks, but even on being exposed to the air it presents only the appearance of a number of minute sparks, with little heat and no flame. The least admission of air to spontaneously ignited coals, however, produces immediate conflagration, not unfrequently leading to serious consequences. Now, if the process of coking could be so far perfected as to re- tain a considerable portion of these combustible qualities of coals, and only expel the carbonaceous smoky portion, the economy would be obvious. Peat has frequently been sug- gested as a fuel for locomotives, and abou| 1 1 or 1 2 years ago Lord Willoughby D’Eresby, so well known for his promotion of industrial experiments, had some peat tried in the Hesperus locomotive, on the Great Western Railway. This engine Avas of Hawthorn’s patent return-tube construction, and required about one third more peat than coke with equal draughts. This peat, however, did not appear at all equal in quality to the best hard black peat of the border districts of England and Scotland, being more like that brown turf cut immediately below the surface of some deep mosses ; for peat, like coals, varies in lighting and heating properties. Mr. Vignoles has also interested himself in the same field, and the peat com. panics now forming are also directing their attention to the 86 NEWCASTLE AND WELSH COKE. various chemical and useful properties of peat and peat char- coal for heating purposes, with what results remains to be decided, as opinions are divided on its economical merits. The gauge contest, which so rapidly promoted locomotion, also atforded some information on the economy of hard and soft coke. During the trials of locomotive engines under the sanction of the Gauge Commissioners, the rival interests of powerful companies were brought into action, and the least point of seeming advantage of load, gradient, wind, or coke was care- fully noted on both sides. The Newcastle or Durham coke principally used on the northern railways bore a high name for its evaporative powers and durability, whilst the Welsh coke used on the Great Western Railway had only a local character inferior to the northern coke, and a claim was made for an equivalent allow- ance for this supposed difference. After these trials were over the question was practically tested in the broad-gauge engines, ending contrary to antici- pation in favour of the softer Welsh coke, as regarded time and loadi with draughts suited to each variety. It was found that the blast pipe used for Welsh coke was too large, and the draught too little for the Newcastle coke, and the engines failed to keep time until the blast pipe was made less. This- of course increased the draught and promoted the combustion of the coke, but it introduced the greater evil of increased re- sisting pressure against the acting pressure on the piston, leaving a balance in favour of the Welsh coke for equal loads at equal velocities by equal quantities of coke. Of the Welsh coke, the softer burnt was likewise found the best, and pro- duced the best results in a locomotive boiler. An annoying instance of this occurred when the power of a particular engine was to be tried. The more beautiful looking upper parts of the coke were selected to fill the tender, and the trial proved a failure for want of steam. The rejected portion of LANCASHIRE COKE. 87 tlie coke, supplied to an engine for ordinary duty, produced a contrary result. In Lancashire again, a contrary opinion was arrived at, and the inability of coke to resist the action of a hard-coke blast was assigned as a reason for its inferiority to harder coke, although it is clear that if this coke could have generated even less steam with a larger blast pipe than the hard coke with a small one, the effective power of the engine to draw a load might still have been equal. For every pound of resisting pres- sure taken away gives more than a corresponding advantage to the acting pressure, since there is less steam to escape for an equal amount of tractive power given out ; hence, with the pre- sent construction of locomotives, it is always a desideratum to use the largest possible blast pipe. The harder the coke, the more is such an object frustrated. Coke, like coals, varies con- siderably in its heating powers, requiring the draught and process of combustion to be carefully attended to for each, so as to evolve the best results. Mr. Wood states, that, as com- pared to the Hutton and Worsley cokes taken as 100, the practical values of six other varieties not named were respec- tively, 76*3, 80*3, 81*7, 89, 90, 90*1, as tried, it would appear, under similar circumstances, which however might not be a fair trial for the peculiarities of each coke, since the tenderness above referred to was stated as one cause of inferiority. The coke column in the annexed tables will show the per-centage of hard coke in different coals as determined by careful ex- periments. The proper regulation of the blast to the coke employed is very essential to economy. To produce the chemical equiva- lent of perfect combustion it requires by weight about 2*66 lb. of oxygen for each pound of carbon. Since f of the air is nitrogen it requires 60 cubic feet of air to produce 1 lb. of oxygen ; therefore an engine consuming coke equal to 25 lb. of carbon per mile would require 25 x 2*66 x 60 = 3990 cubic feet of air to pass through the furnace during the time 88 COMBUSTION OF COKE. of running one mile. It is this vast quantity of air required which renders the blast-pipe necessary, though it absorbs power varying at high velocities from 25 to 30 per cent, of the work- ing power of the steam. A larger supply of air is, however, required practically to meet the loss from various causes. It is stated that during the steam-coal investigation no com- bustible gases escaped up the chimney, but, on the contrary, much free oxygen, rather a singular result. This experimental boiler had a split” flue, a class which has usually an eddy” favourable to the retention of the cold air or gases, and air admitted at the back of the grate might thus pass away uncombined, and form a portion of the gases ascending in concentric or other separate circles of their own. There is however, this difficulty ; if the combustion was perfect the absorption was less perfect by 20 per cent, than a larger boiler of the same class at the Par Consols mine. Be this, however, as it may with stationary boilers set with split flues, in locomotive boilers there is evidently much com- bustible gas passing off, since it readily ignites either in the smoke-box, or at the top of the chimney when air is supplied. To economize the consumption of these escaping gases Mr. Deurance introduced a gas fire-box between the coke fire- box and the tubes, making a double fire-box, like those used also for coke. A series of short tubes communicated from the coke to the gas fire-box through the divisional water space, and the admission of air was regulated by valves under the control of the driver. This was, with considerable success, tried for eleven months on the Grand Junction Rail- way both with coke and coals mixed, and separately. The cost was from to 6d. per mile, including all repairs for the regular passenger traffic, of which particulars wdll be given in their place. Even without such a plan benefit is found to arise from admitting air occasionally by the fire-door according to the state of the fire and the height of the door from the level of the fire surface, but uniform admission is COKE OVENS. 89 detrimental, and therefore it requires to be carefully regulated to produce perfect combustion. Coke Ovens. Like charcoal, coke was former!}^ made in heaps roughly covered from the air, but furnaces or ovens are now employed for that purpose. These ovens are of various forms, but it is not so much the form as the proper admission of air to the coking coals which is of importance. With a well-regulated supply of air there is not found to be any marked superiority in the most costly ovens over the cheaply constructed circular oven of which Figs. Nos. 11, 12, 13, show an elevation section, Fig. No. 11. Fig. No. 12. Fig. No. 13. and plan. They usually hold about five or six tons of coals, and the air is admitted by the doorway vX a a which is finally closed as required and luted with clay. When the process of coking is completed the brick-built door is taken down and water injected into the oven to cool down the coke. On this being done, the coke is removed by the crane C, and the large iron shovel s^ from the oven, which is then ready to be filled again, k. number of these ovens may be erected in one cluster, and connected wdth a central chimney, as is done by Messrs. Cory, New Barge Wharf, London. Church’s circular ovens w'ere on the same general plan, but with a series of air passages below the coke bed, but not in contact with the coke. When the coking process was complete 90 cox’s PATENT these passages were opened, to admit a current of cold air to aid in cooling down the hot coke, which was effected by care- fully excluding all air from the oven without the use of water. Coke so made was therefore perfectly dry and free from hy- grometric water (until it absorbed it from the atmosphere), and enjoyed considerable repute for its steaming power. The plan of cooling with water is now generally preferred, and when done in the oven there is a better return of large coke than when drawn out hot and cooled outside the oven. Cox’s patent oven is arranged to make both coke and gas at one time, as seen in Fig. No. 14. Fig. No. 14. Cox's Oven. In this oven the air is admitted by the side passages a a, passing along the brick work and opening into the back of the oven, as seen in Fig. No. 15. By this arrangement the air is Fig. No. 15. Longitudinal Section. COKE OVEN. 91 heated before it comes near the coking coal, and passes hy the due to the chimney, as seen by the arrows. When gas is re- quired a retort R is placed in the upper arch, which is acted upon by the escaping heat of the oven. For coke alone the upper arches might be dispensed with, and the chimney placed at the front instead of the back, which would reduce the cost of erection without impairing the quality of the coke, h h are eye holes for observing the process of coking by the escaping products of combustion, and also for admitting air to promote the draught, as may be required. The coke is drawn out hot on the Cradle” C., Figs. No. 16, 17, which show the Figs. 16 and 1 7. A plan and edge view of this implement. It is placed on the door of the oven, as seen in Fig. 15, and the coals put in the oven afterwards. When the coking is completed the door is opened, and a strong chain from a crab is attached to the hook of the cradle, and by the exertion of two or three men working the crab, the whole mass is drawn at once from the oven hot, and cooled with water afterwards. The coke being more friable 92 BRISTOL AND EXETER when hot than when cold, there is rather more small coke hy this plan, than hy cooling in the oven. Amongst the most recently constructed coke ovens are those of the Bristol and Exeter Eailway at Bridgewater. In them is embraced the principal improvements of late years, with modifications of both Church’s and Cox’s patent ovens. Church’s cooling air passages are made to come in contact with the coke, to promote equal ignition, and the side-air passages have frequent openings into the oven, whilst the upper passages further regulate the admission of air, as fully illustrated in the following drawings from the Aide Memoire of Military Sciences.” Fig. No. 18. Cohe Oven. Ground or Floor Plan. COKE OVENS 93 Fig. No. 18, is a ground plan of 8 coke ovens, comnumi- cating with a central chimney, showing the lowest side-air passages leading from the front, and by the transverse dotted passages underneath the coals to promote equal ignition of the whole mass at once. When this is done these passages are closed for that occasion. Fig. No. 19. Coke Oven. Fig. No. 19, is a plan at the upper air passages for re- gulating the supply to the burning fuel. The side open- ings introduce the air so as to distribute it as equally as possible above the burning mass. The spaces parallel with the chimney between the ovens are filled up with dry rubble, as shown in both plans. 94 BRISTOL AND EXETER Fig. No. 20. Coke Oven. Transverse Section at A B, Fig. 19. Fig. No. 20 is a section, at A B of Fig. 19, showing the vertical construction of the ovens, air passages, side openings, lowest air passages, and central openings, leading into the flue which connects them with the chimney. Fig. No. 21. Coke Oven. Longitudinal Section at E F, Fig. 19. Fig. No. 21, is a section of two ovens at E F, Fig. 19, show- ing the longitudinal plan of the ovens and air passages, with the manner of their junction at the back. COKE OVENS. 95 Fig. No. 22. Coke Oven. Longitudinal Section of Oven and Chimney Flues. Fig. No. 22, is a longitudinal section of the oven and chimney "flue, with the dampers A B. Fig. No. 23. Fig. No. 24. Coke Oven. Fig. No. 23, is a section between the ovens at C D, showing their connection with the chimney. Fig. No. 24, is a front elevation of two ovens, showing the external air orifices A B, with the form of the cast-iron doors and fittings. The process of making coke with all these ovens, is to fill them with their respective quantities of coals in such rotation 96 PROCESS OF MAKING COKE. as to produce a daily supply of coke. When the coke is cooled in the oven, the coals require to he lighted, hut when the coke is drawn out hot, the coals then put in ignite readily by the heat of the oven. The ’door is then lined inside with fire bricks, and closed and luted with fire clay, to make it air- tight. Sometimes no door is used, and the opening is built up with fire bricks, leaving regulating air passages to be closed as the coking progresses. The duration of the process is from 48 to 96 hours, but is a good deal dependent on the composi- tion of the coals, the state of the atmosphere, and the class of oven employed. When coals contain little or scarcely any sulphur, the process is slow, although an excess of sulphur is injurious to coke, and electricity has been employed to remove it before the coke was withdrawn from the oven. Still a certain amount of sulphur promotes combustion, and in this respect the Ehonda Valley coal of South Wales makes better coke than the Newport coals, which, from containing more sulphur, make superior household coals. It is the duty of the coke burner to watch the progress of the combustion by the eye-holes for that purpose, and to regu- late the admission of air accordingly. When scarcely any flame can he observed to pass from the heated mass of fuel the air is altogether excluded for some time before the oven is ready to be drawn,” or ‘^'cooled,” as the case may he. Since, therefore, even with the most carefully arranged air passages, much depends upon the care of the burner, there exists, as previously remarked, an opinion amongst experienced men that with such care judiciously exercised, the cheaper class of ovens are nearly as good as the most expensive ones for all practical purposes. The Great Western Hallway Com- pany have both classes of ovens, and find no material differ- ence in the products, either in quantity or in quality. The Bristol and Exeter ovens yield about 13 cwt. of good coke, 6'2 cwt. of small and waste coke, and some ashes, fit for lime burners, from a ton of Cardiff coals. The coke is drawn out of the ovens hot, by a cradle similar to Cox’s, Figs. Nos. COALS AND ANTDEACITE FOE LOCOMOTIVES. 97 16, 17, which probably increases the comparative quantity of small to large coke. The superior economy of coals for generating steam has led to several trials to effect that object, without evolving smoke. Gray and Chanter have each especially designed fire- boxes for this purpose, and Durance has also tried it in his gas fire-box referred to. Whilst therefore ingenuity continues to be directed to obtain this object, there is no reason to doubt its ultimate success, when coals either in union with coke or not may be profitably employed in railway engines. From the high ratio of carbon in anthracite, and its almost smokeless combustion, it would appear well suited for locomotive pur- poses, more especially as it also combines combustible gases, and requires a draught similar to coke. The following abstract of the properties of various coals and anthracite will therefore supply desirable information to the locomotive as well as to the marine engineer on these essential points in the economy of steam power. COALS. The preceding remarks on heat, combustion, and coke, will be rendered practically available in selecting coals for particular purposes, by the following tabular arrangement of 37 varieties of Welsh, 19 of Newcastle, 28 of Lancashire, 8 of Scotch, 1 of Irish, 8 of Derbyshire, 9 of Van Diemen’s Land, 2 of Pa- tagonian, 3 of Bornean, 6 of Chilian, 5 from different localities, and 42 of American coals, with 6 of patent fuels. With the exception of the American varieties, the 132 other varieties are abstracted from the able reports of Sir H. De la Beche, F.B.S., and Dr Lyon Playfair, F.B.S., ‘‘On Coals suited to Steam Navy^” begun in 1846, and the last report issued in April, 1851. The American government had instituted a similar inquiry into coals, and a copy of their report coming into the hands of Mr. Hume, M.P., that able public man lost no time in forwarding it to the Lords of the Admiralty, F 98 - EVAPOEATIYE YALEE OE COALS (loth June, 1845,) suggesting that a similar course should be pursued to ascertain the best coals for the naval steamers of this country.” This -was promptly undertaken by the Admi- ralty, who on the 28th June issued instructions to ascertain how the ‘‘ inquiry could be conducted with the greatest effect.” To the able manner in which this investigation has been con- ducted in all its details, and to the lucid arrangements of the reports themselves, we are indebted for this valuable addition to our knowledge of the properties of coals generally. In endeavouring to compress the lengthened remarks on the combustible peculiarities into a tabular form, the leading fea- tures only have been given, and there was some difficulty to con- vey a brief yet fair impression of the text. It has however been attempted, with every desire to do impartial justice in a matter so important to the public, and to each coal-mine proprietor. The properties sought to be determined by these experi- ments were, briefly, 1st. Evaporative value ; 2nd. Mechanical structure ; 3rd. Combustible character ; and 4th. Chemical composition. Evapoj'ative Value. To Smeaton we believe is due the merit of the first sys- tematic attempt to define the comparative effect of different coals. In 1769 he constructed an experimental engine, having a cylinder nearly 10 inches diameter and 3 feet stroke. The boiler consumed 55 lbs. of coals per hour, and evaporated 6’141bs. of water under a pressure of 7*8 lbs. per square inch for each pound of coals. Taking the Halston coals from Yorkshire as evolving an evaporative power of 100, he found the useful ratio of the others used by him as under — Halston . . 100 Welsh . . .110 Berwick Moor . . 86 Newcastle . . 120 Middleton . .110 Cannel . . . 130 Coke t of that of the coal it was made from. AND OTHER FUELS. 99 The quantity of coke to coals he found about 60 per cent., or nearly the same as at present. Although recent investi- gations have placed the Welsh coals at the top of the practical evaporative test, yet these early experiments bear ample evi- dence of the care with w^hich they had been made. Under his best boilers Smeaton found 7*88 lbs. of water by 11b. of coals, from 212®, as the evaporative value of Newcastle coals. "Watt’s improved boiler gave 8*62 lbs., and this was long con- sidered the standard till the Cornish engineers gradually in- creased it to 10*74 lbs. in 1840, and in 1846 to 12*89 lbs. of water evaporated by 1 lb. of coals. Dr. Ure gives the heating power of 1 lb. avoirdupois of different fuels as under — 1 lb. of Heats water from 52^ to 212® Evaporates water from 212® Weight of air to burn 1 lb. of the fuel. lbs. lbs. lbs. Dry wood . 35 6*36 5*96 Ordinary wood 26 4*72 4*47 Wood charcoal 73 13*27 11*46 Coal . 60 10*90 9*26 Coke 65 n8*88 11*46 Peat charcoal 64 18*63 9*86 Peat . 30 5*45 4*60 Hydrogen gas 76 13*«1 14*58 Oil . . . 78 14H8 15*00 Wax . 78 14*18 15*0 Tallow 00 14*18 15*0 Common alcohol . 52-6 9*56 11*6 Mr. Wicksted gives the following comparative ratios of prac- tical or realized evaporation and prices at London Bridge. The F 2 100 EYAPOEATIYE YALUE OF AKTHEACITE. latter now requires modification, to the extent seen in the last column. Name of Fuel. Water evaporated from 52° by 1 lb. of fuel. Cost per ton at London Bridge. Sept. 18M. lbs. s. d. s~. d. Welsh, best . . . . 9-493 17 11 21 0 Anthracite . . . . . 9-014 17 0 21 0 Newcastle, best small 8-524 16 1 16 6 ,, average 8-074 15 14 9 Welsh, average . . . . 8-045 15 20 0 Gas Coke . . . . 7-908 14 11 14 4 Half coke and half Newcastle small 7*897 14 lOi 14 0 Half Welsh and half Newcastle 7*865 14 10 17 10 Half Newcastle and half Derbyshire 7*710 14 6i 13 9 Newcastle, average of large 7-658 14 15 8 Derbyshire . . . . . 6-772 12 9i 12 9 Blythe Main Northumberland 6-600 12 The value given here for anthracite, is, however, much less than that found hy Messrs. Josiah Parkes, and Charles Manby, of the Institution of Civil Engineers, in 1840, from a series of experiments made on anthracite as a steam fuel. With a boiler, having 340 square feet of heating surface the result gave 13*48 lbs. of water as the evaporative valRC of 1 lb. of the fuel, compared with 1 1*89 lbs,, the then highest recorded duty of a Cornish boiler, having 961 square feet of heating surface, or 13 per cent, in favour of the anthracite with a small boiler. What the difference would have been in boilers of equal heating areas they had not the means to decide, but considered 13 per cent, as the minimum difference of value be- tween anthracite and the best Welsh coals. The subject was one of growing importance, and under the sanction of the Government, it has now been ably investigated in the following manner. The evaporative value was arrived at by taking the mean of three separate days’ trials with each fuel in a small Cornish boiler 12 ft. long, 4 ft. diameter, with inside flue of 2 ft. 6 in. YAEIATION OF BULK OF WATER BY UEAT. 101 diameter and flat ends. The fire was placed in one end of this flue, and the current of heated gases returned by split ” flues round each side of the boiler to the front, where they united and passed under the boiler to the chimney. During two of the trials the pressure on the safety valves was 1 lb. per square inch, and usually 3 lbs. during the third trial. As the comparative weight to bulk of water varies with its temperature, the necessary corrections were made by the fol- lowing table, which shows a difference of 85*6 lbs. between the temperature of 70^ and 212° in the actual quantity of water in the boiler. Table No. 17. Temper- ature of Water, Fahren- heit. Ratio of apparent to real Weight. Actual W'eight of Water in Boiler when filled to Normal Point. Difference between actual and apparent Weight. o 70 1-0000 lbs. 4730000 0-000 80 0-9996 4728-108 1-892 90 0-9992 4726-216 3-784 100 0-9987 4723-950 6-050 110 0-9983 4721-960 8-040 120 0-9979 4719-097 10-903 130 0-9974 4717-795 12-205 140 0-9971 4715-283 14-717 150 0-9967 4714-012 15-988 160 0-9954 4708-242 21-758 170 0-9940 4701-620 28-380 180 0-9923 4693-579 36-421 190 0-9901 4683-173 46-827 200 0-9879 4672-767 57-233 202 0-9869 4668-037 61-963 204 09859 4663-307 66-693 206 0-9849 4658-577 71-423 208 0-9839 4653-847 76-153 210 0-9829 4649-117 80-883 212 0-9819 4644-387 85-613 102 HEAT m WATEE AT^H STEAM. The heating effect of the wood used to light the fires was first experimentally determined, and its effect, — ascertained each trial by the following table based on Regnault’s experi- ment, — was deducted from the total evaporation of both wood and coals. Table No. 18. SPECIFIC and diffused HEAT OF W^ATER AND STEAM FROM 32° TO 446° FAHR. Air Ther. Cent. Mercu- rial Cent. Number of Unities of Heat aban- doned by one kilo, of water in de- scending from T to 0®. Air Ther. Fab. Mercu- rial Fab. Number of Unities of Heat eon- tained in one pound of water at T«. Mean spe- cific Heat of Water between and T cent, or between 32® and T Fab. Specific Heat of Water from T to T -h d T. Latent Heat of Steam saturated to the temper- ature T. Cent. Fab. o 0 o 0-000 o 32 o 32-000 1*0000 606-5 1091*7 10 , . 10-002 50 50-003 1-0002 1-0005 599-5 1079*1 20 . , 20 010 68 68-018 1-0005 1-0012 592-6 1066*7 30 . , 39-026 86 . , 86-046 1-0009 1-0020 585-7 1054-2 40 , , 40-051 104 104-091 1-0013 1-0030 578-7 1041-6 50 50-2 50-087 122 122-36 122-156 1-0017 1-0042 571-6 1028-9 60 60-137 140 140-246 1-0023 1-0056 564*7 1016-4 70 . , 70-210 158 158-381 1-0030 1-0072 557*6 1003*7 80 , , 80-282 176 176-507 1-0035 1-0089 550-6 991*1 90 90-381 194 194-685 1-0042 1-0109 543-5 978-3 100 100-0 100-500 212 212-0 212-900 1-0050 1-0130 536-5 965-7 110 110-641 230 . . 231*153 1-0058 1-0153 529-4 952-9 120 120-806 248 249*450 1-0067 1-0177 522-3 940-1 130 130-997 266 267-794 1-0076 1-0204 515-1 927-2 140 141*215 284 286-187 1-0087 1-0232 508-0 914*4 150 150-0 151-462 302 302-0 304-623 1-0097 1-0262 500-7 901-2 160 161-741 320 . . 323-133 1-0109 1-0294 493-6 888-5 170 172-052 338 341-693 1-0121 1-0328 486-2 875*1 180 182-398 356 . , 360-316 1-0133 1-0364 479-0 862*2 190 192-779 374 379-002 10146 1-0401 471-6 848*9 200 200-0 203-200 392 392-0 397-760 1-0160 1.0440 464*3 835*7 210 213-660 410 416-588 1-0174 1-0481 456*8 822-2 220 224-162 428 , . 435-480 1-0189 1-0524 449*4 808-9 230 234-708 446 454-474 1-0204 1-0568 441*9 795-4 The correction for variation of temperature of the feed- water was made by the following tabular ratios. EVAPORATION OF DIFFERENT ROILERS. 103 Table No. 19. Tempera- ture. Fah. Actual weight of an Unity of Water. Tempera- ture. Fah. Actual weight of an Unity of Water. o 40 1*001464 o 62 1*000712 42 1*001451 64 1*000534 44 1 001439 66 1*000356 46 1*001426 68 1*000178 48 1*001414 70 7000000 50 1*001401 72 *999763 52 1*001294 74 *999527 54 1*001196 76 *999290 56 1*001094 78 *999054 58 1*000992 80 *998818 60 1*000890 Comparative Evaporation of different Boilers, To determine how far the experimental boiler gave results as compared with the best Cornish boilers, Mr. Phillips went to the Par Consols mine and had 11 9,700 lbs. of water eva- porated from 92° by 11,730 lbs. of coals, equal to 10*204 lbs. of water by 1 lb. of coals, or 11,428 lbs. from 212°. The Mynydd Newydd experimental coals had the nearest chemical composition to those used in the above trial, and only evaporated 9*52 lbs. of water per lb. of coals from the ex- perimental boiler, being very nearly 20 per cent, less than in the larger boilers. The ratios therefore of realized evapora- tion in the tables multiplied by 1*1995 will give the value for boilers of the same evaporating power as those at the Par Consols mine. From this it will be noticed that the tabulated evaporative results are only comparative, under the same boiler and con- ditions, for the precise value would vary according to the merits of the particular boiler employed. 104 COKE IK COALS. Coking Quality of Coals. The quantity of coke in the several varieties was ascertained by subjecting a portion of them in a crucible to a white heat for several hours, and weighing the coke left in the crucible. This useful column in the tables will be a new source of information for the selection of particular coals for coking purposes. During the experiments only one sample of loco- motive coke was sent for investigation. This was made by Messrs. Cory, of New Barge Wharf, Lambeth, from Andrews’s House Tantield coals, in a plain circular oven, having a brick- built door, and the coke cooled with water in the oven, yield- ing about 65 per cent, of coke from the coals used. To test the practical with the theoretical elfects of coking, three sepa- rate trials were made in the crucible on coals from the same mine, which gave a mean of 65*13 per cent, of coke to coals, and was regarded as satisfactory evidence of the practical re- turn of coke by Messrs. Cory’s process of producing hard coke. Although in coking the weight of the fuel decreases 35 per cent, the bulk appears to gain about 11*7 per cent, as seen in the table. In one trial under the experimental boiler with the draught increased by blowing the steam into the chimney, the coke evaporated about 20 per cent, less water for equal weights than the coals it was made from. The same increased blast was used both with the coke and coal to give comparative results, and the following statement of this trial will show the precautions taken to ensure accuracy with all the experiments. Table No. 20. COMPARATIVE EVAPORATION OF WATER BY COALS AND COKE UNDER THE SAME CONDITIONS. Particulars. Coals. Coke. Fire lighted . . . . . 10 h. 0 m. 9 h. 0 m. Steam up , . . . . llh. Om. 10 h. 15 m. EYAPORATION BY COALS AND COKE. 105 Particulars. Coals. Coke. Wood used .... 10 lbs. 10 lbs. Initial temperature of water in boiler 192° 203® Temperature of water in tank . 50® mean 50® mean Barometer .... . 29*7 mean 29*65 mean Extremes of external thermometer . 320—560 36°— 560 Extremes of internal thermometer . . 58°— 68° 520—650 Dew point .... . 48° mean 461 mean Area of damper open . 168 in. 168 in. Fuel consumed . 2119 lbs. 2184 lbs. Ashes left . 41 lbs. 94 lbs. Combustible matter in ashes in general from about 20 to 70 per cent. averaging about 38 per cent. Cinder left .... 12 lbs. none Combustible matter in cinder in general, from about 20 to 80 per cent. averaging about 55 per cent. Clinker .... . 42 lbs. 25 lbs. Average soot in flues . . none none Combustible matter in soot in general, from about 55 to even 90 per cent, averaging about 70 per cent. Water evaporated . 17895 lbs. 15275 lbs. Water evaporated from 212° by 1 lb. . . 9*91 lbs. 7*91 lbs. Burnt per hour per square foot of grate 12*4 lbs. 12*84 lbs. Duration of Experiment 34 h. 34 hours Specific gravity 1-264 Mean weight of 1 cubic foot « 52-1 30- Economic weight per 1 ton . a 42-99 74*66 Cohesive power . . « . Pressure of steam blowing off* . • 3 lbs. 3 lbs. Evaporation per hour . 526-3 lbs. 449*2 lbs. Fuel per hour . 62-3 lbs. 66*2 lbs. * The per-centage of combustible matter in the ashes, cinders, and soot, is not from these experiments, but an average for general reference. From this table it is seen that 1 lb. of coals evaporated 9*91 lbs. of water and 1 lb. of coke only 7*91 lbs. or 20*1 per cent, less than the coals. The quantity evaporated in a given time was also greater by 77 lbs. per hour for the coals, amount- ing to 2620 lbs. of water in the 34 hours’ trial. F 3 ]06 MECHANICAL STEUCTUEE ANB The increased draught also increased the evaporative results of the coals 5^ per cent, over the previous trial with the ordinary- flue draughts only. The evaporative-poi^^cr column includes the estimated loss from the unconsumed combustible matter in the residue. The realized column is what was actually obtained during the trials. Smeaton, it has been remarked, found a loss of ^ of steam- generating power from coke, or 16*7 per cent, and 34 per cent, of loss in the manufacture, being a near approximation to the data found from these experiments. Mechanical Structure. The general appearance of the coal was noted, and its com- parative bulk to weight for stowage was ascertained by filling a box of 6 cubic feet capacity, with each variety tried, and care- fully noting the weight per cubic feet. This weight multiplied by the realized ratio of evaporation per lb. gives the evapora- tive power in 1 cubic foot of the particular coals. The cohesive property was found by placing 100 lbs. of suitable sized firing pieces which would not pass through a sieve of 1-inch mesh, in a vertical wooden cylinder, 3 feet diameter and 4 feet high, ^his cylinder had internal angular shelves, which on its being turned round on its axes, carried the coals upwards and let them fall to the bottom, which more or less broke them according to their natural cohesion. Each variety was subjected to two trials of 50 revolutions each time, and then the mean number of pounds of coals which would not pass through the 1-inch mesh sieve is given in the tables as the comparative cohesion per cent, to resist ordinary at- trition. The ordinary hygrometric water in coals w^as determined by drying them at a temperature of 212^, and has been placed under this heading as more allied thereto than to chemical union, that more extended observation on the effect COMBUSTIBLE CITABACTER OF COALS. 107 of such water from fuel on the practical results might be noticed. Combustible Character, The combustible peculiarities were noted from observation and analyzation of the residue arising from combustion. The ease or difficulty of lighting, the draught best suited, the rapid or slow combustion, the coking or open burning, the amount of attention from the stoker, the quantity of smoke, ashes, cinders, and clinkers, with the ratios of unconsumed combus- tible matter in the residue were all noted. Of the residue, the whole per-centage is given, and the clinkers separately. Ashes are no doubt troublesome when in large quantities, but these may be approximately ascertained by the chemical analysis. Clinkers are, however, more troublesome, and fusible ones which adhere to the fire bars particularly so in obstructing the draught. In the table these are marked ad. for adhesive. In locomotive furnaces the formation of clinkers is very prejudicial to the generation of steam, and Goldsworthy Gurney, Esq., from his unpleasant ex- perience of these effects on his common-road steam carriages, calls them ‘"fire eaters.’" He mentions an experiment made by himself and Sir George Cayley, Bart., to test the effect of clinkers in retarding the generation of steam. They introduced a little lime to hasten the formation of the clinker, which soon exhibited greater effects than was anticipated, rendering it difficult to keep up the steam. The per-centage of combustible matter in the residue varies in proportion to the quantity of small coals which falls through the grate, and generally the increase of a per-centage of residue would indicate an increased per-centage of combus- tible matter also, over the per-centage when the fuel was fairly consumed, and the residual matter comparatively small. It will be noticed that the Newcastle coals so geriertliy em- ployed for domestic use in London are of a caking, smoky 108 CHEMICAL COMPOSITION AND character, which, however suitable the caking is for the house or forge fire, is not so suitable for steam furnaces. It might be worth a fair trial to ascertain whether keeping the open- burning Welsh household coals in water would impart that coking quality to them in the house fire which it does in forge operations, as their cleanly smokeless character and superior heating power are far more than compensation for the more easily ignited bituminous coals. An experiment with 7 lbs. of Pyle coals in their ordinary state, and 7 lbs. wet with water, showed a decided difference on a common house fire in coking in favour of the wet coals, but was found to operate the reverse way in evaporating water, for the dry coals kept a more open fire, and evaporated 2 lbs. more water in 6 hours. A further experiment by im- mersing 20 Ihs. of these coals in water for 24 hours showed that they absorbed no appreciable quantity of water, but that due to their wet surfaces, and when these were dry no percep- tible difference in weight was detected. Chemical Composition, The chemical analysis was carefully made from a fair average sample of the coals as mined, checked by an analysis of pure coal from the same sample. Coals in their ordinary state contain more or less shaly, whitish, dull blackish, ex- traneous matter or veins of iron pyrites, besides the pure coals, which decrease the evaporative value whilst they in- crease the duty of the stoker and per-centage of residual matter. An analysis therefore of the pure coal, or even the specific gravity of the pure coal would be no just criterion of the prac- tical composition or practical weight per cubic foot. The analysis therefore of the average sample only as mined is given under this heading, as the weight per cubic foot was given under the heading of mechanical structure. The following Tables show the various substances found in Coals and their Ashes by analysis : — CALOEIFIC VALUE OF COALS. 109 Table No. 21. PRODUCTS FROM DESTRUCTIVE DISTILLATION OF COALS. Name of Coal. 1 I Coke. U H Water. Ammonia. Carbonic Acid. Sulph. Hy* drogen. Olefiant gas and Hy- dro-carbon. Other in- flammable gases. Craigola Anthracite (Jones & 85-5 1-2 3-1 0-17 2-79 traces 0-23 7-01 Co.) . 92-9 none 2-87 0-20 0-06 0-04 . , 3-93 Old Castle Fiery Vein 79-8 5-86 3-39 0-35 0-44 0-12 0-27 9-77 Ward’s Fiery Vein . 1-80 3-01 0-24 1-80 0-21 0-21 Binea . 88-10 2-08 3-58 0-08 1-68 0-09 0-31 4-08 Llangennech . 83-69 1-22 4-07 0-08 3-21 0-02 0-43 7-28 Table No. 22. INCOMBUSTIBLE MATTERS IN COAL ASHES. Name of Coal. . Silica. Alumina and Ox- ide of Iron. Lime. Mag- nesia. Sulph- uric Acid. Phos- phoric Acid. Total per- centage. Pontypool . 40-00 44-78 12-00 trace 2-22 0-75 99-75 Bedwas 26-87 56 95 5-10 1-19 7-23 0-74 98-08 Warlich’s pat. fuel 25-20 57-30 6-90 trace 7-85 99-41 Porthmawr . 34-21 52-00 6 199 0-659 4-12 0-633 97-821 Ebbw Vale . 53 00 35-01 3-94 2-20 4-89 0-88 99-92 Fordel Splint Wallsend Elgin . 37-60 52-00 3-73 1-10 4-14 0-88 99-45 61-66 24-42 2-62 1-73 8-38 1-18 99-99 Coleshill . 59-27 29-09 6-02 1-35 3-84 0-40 99-97 Calorific Value, This was determined chemically and also practically, by enclosing 5 grains of finely powdered coal, with 2000 grains of litharge in an air-tight crucible, and weighing the but- ton” of lead melted down. The tables give the mean of three separate trials with each fuel. Estimating the heating value of carbon as 13,628, the tabular value multiplied by *45, gives the lbs. of water which 1 lb. of each fuel should raise from 30° to 212° where the structure of the coals is favour- able. As this is not always so, we have preferred the litharge value for practical reference, since the chemical value is from 10 to 1 2 per cent, higher on the average than the litharge value. 110 WELSH COALS Table No. 23. — comparative cost, mechanical, combus| OF thirty-seven VARIEj ji NAME OF COAL. COST, per ton, at the MECHANICAL STRUCTURE. combustible! Nearest Seaport. 1 Bulk per ton, cubic feet. Weight per cubic foot— lbs. 1 Weight of Water in Coals, 1 per cent. I Cohesion of large Coals, per cent. Light. 1 Draught required. Burns. Aberaman, Merthyr . 2nd sample 10s. 45-80 48-9 -41 74- ordinary . quick freely ,, . 1st sample 43-57 51-4 ord. quick freely EbbwVale 42-26 53-3 1-34 45- easily ord. clear Thomas’s Merthyr 42-26 53- 1-42 57-5 ord. ord. freely DufFryn 42-09 53-22 1-13 56-2 readily . ord. f freely and (.clear Nixon’s Merthyr 10s. 43-32 51-7 1-22 64-5 difficultly quick stg, flame Binea . . . . 7s. to 10s. 39-24 57-08 3-58 51-2 slowly . ord. freely Bedwas 44-32 50-5 1-28 54- easily ord. freely Hill’s Plymouth Works 8s. to 9s. 43-74 51-2 1-26 64- slowly quick steadily . Aberdare Co.’s Merthyr 45-43 49-3 1-40 74-5 ord. ord. freely Gadly 9-ft. seam 40-87 54-8 1-44 76- ord. strong . stg. flame rstrng.-) Resolven 10s. 38-19 58-66 1-55 35- easily ord. < open >- L flame J f cake 1 Mynydd Newydd 39-76 56-33 -61 53-7 easily ord. < and [ 1 obs. J r cake Abercairn 44-53 50'3 7-11 54-5 easily ord. and V . 1 C I Anthracite, Jones & Co. 38-45 58-25 2-87 68-5 diff. quick V. ODS. J inten. ht. Ward’s Fiery Vein 6s. 3d. to 9s. 39-00 57-433 3-01 46-5 easily ord. C freely "j “j and > Neath Abbey . 37-77 59-3 1-02 50- easily ord. freely Craigola 37-23 60-166 3-1 49-3 easily ord. freely . j Gadly 4-ft. seam 43-41 51-6 1-24 68-5 ord. strong . stg. flame i Machen Rock Vein . 46-56 48-1 2-5 52-5 easily ord. clear Birch Grove Craigola 43-92 51- 1-51 59- ord. ord. r clear i -< and > Llynvi .... 42-02 53-3 1-13 ord. ord. A J steadily . Cadoxtan 6s. 6d. to 10s. 38-55 58-1 1-52 diff. badly Old Castle Fiery Vein 6s. 6d. to 9s. 43-99 50-916 3- 57-7 easily ord. C freely") < and > r ca^e 1 Vivian and Son’s Mirfa 7s. 6d. 46-76 47-9 -63 540 easily moderate and [ 1 obs. J ; Llangennech . 39-84 56-93 4 07 53-5 ord. ord. slowly . 1 Three -quarter Rock Vein 39-72 56-388 1-67 52-7 easily strong . cake mod. Pentrepoth 38-80 57-72 46-5 diff. ord. Cwm Frood Rock Vein 9s. 6d. 40-52 55-277 1-12 72-5 ord. ord. . 1 smoky . CwmNantyGros 40- 56- -9 55-7 easily ord. moderate Brymbo Main . 6s. 8d. 47-65 47- 4-50 quickly . ord. . « clear r cake 1 1 Vivian & Son’s Rock Vein . 7s. 6d. 45-80 48-9 1-45 70-5 quickly . mod. qk. I Sbs J ' Coleshill 8s. 6d. 42-26 53- 4-91 62- quickly . ord. . 1 L OOS* J freely . ! Brymbo Two-yard 7s. 46-76 47-9 3-35 79-5 easily ord. . ( clear Rock Vawr 8s. 6d. 40-72 55- 2-33 65-5 easily ord. . 1 moderate Porth-Mawr Rock Vein 9s. to 9s. 6d. 42-02 53-3 1-7 62- easily ord. . 1 freely Pontypool 9s. 6d. 40-21 55-7 1-6 57-5 easily ord. . 1 freely Pentrefelin 3s. 9d. 38-85 66-166 1-33 52-7 diff. ord. ( Ids. 1 ' (. SCO. J WELSH COALS, 111 IDLE, EVAPORATIVE, COKING, AND CHEMICAL PROPERTIES ^ES OF WELSH COALS. IIARACTERISTICS. EVAPORATIVE VALUE. CHEMICAL COMPOSITION. Steam Water evapo- 1 E raised rated from 212° s < S3 be ^ by 11b. of Coals. C3 U4 •3 6 la bc 1 c 0 « § 0 V a a 0 d O' (U (1 oS a • c 0 Or^ a Xfl 3 0 c. ft 1 ft s ft u 0) Pi 0 s:; 0 < a Xfl ft tn (U 6 •J2C/3 0 -^ 0 S (U .. -o S3 0 c tfo ^ a •12 Cj £3 1 In Time— m 0 ft a (U a 0 1 Power of—] j. Realized— 1 A f-< . p.^ 0 "rt Carbon— Hydrogen- 1 c ■ QJ be K 0 Nitrogen— 1 ^ rP 25* s cc ft i •S Coke— pe rdinary . little 13-3 6*5 159*9 22 198 10*75 90*94 4*28 *94 1*21 1*18 1*45 85* rd. little 13-0 7*38 159*9 23 209 10*04 9*53 ireful . moderate 9-5 5*87 159*9 43 187 10*64 10**21 460*22 89*78 5*15 *39 2*16 1*02 1*50 77*5 ttle little 3-9 9*03 164*8 20 209 10*72 10*16 520*8 90*12 4*33 2*02 1*00 *85 1*68 86*53 itle none none 7*8 150*0 11*80 10*14 409*33 88*26 4*66 •60 1*45 1-77 3*26 84*3 ttle little 5-7 11*31 166* 38 209 10*7 9*96 511*4 90*27 4*12 2*53 *63 1*20 1*25 79*11 ttle little none 8*22 158*2 29 216 10*3 9*94 486*95 88*66 4*63 1*03 1*43 *33 3*96 88*10 ttle 22*9 4*79 141* 26 197 9*99 9*79 476*96 80*61 6*01 1*5 1*44 3*5 6*94 71*7 ireful . little To 7*01 170*3 42 195 10*18 9*75 531*6 88*49 4*0 3*8*2 *46 *84 2*39 82*25 ttle little 9-8 8*38 170*6 58 193 10*27 9*73 489*5 88*28 4*24 1*65 1*66 *91 3*26 85*83 .ireful . none 6-0 17*05 170*8 27 208 10*46 9*56 517*3 86*18 4*31 2*21 1*09 *87 5*34 86*54 ireful . little none 4*71 160*8 30 198 10*44 9*53 390*25 79*33 4*75 in ash. 1*38 507 9*41 83’9 luch much 57*2 8*28 151*7 30 208 10*59 9*52 470*69 84*71 5*76 3*52 1*56 1*21 3*24 74*8 'luch 1 mod. 20* adhes. 4*83 153*8 12 207 9*63 9*47 480* 81*26 6*31 9*76 •77 1*86 2*04 6*84 .ireful . none little 9*58 167*4 110 194 9*7 9*46 409*37 91*44 3*46 2*58 •21 *79 1*52 92*9 rd. 1 little 54-6 7*44 157*3 48 178 10*6 9*40 529*9 87*87 3*93 in ash. 2*02 *83 7-04 •equent . much 19’2 adhes. 5*44 156*0 52 155 9*65 9*38 546*1 89*04 5*05 1*07 1*60 3*55 61*42 rd. little 30-7 9*27 160*4 25 209 9*66 9*35 441*48 84*87 3*84 7*19 *41 *45 3*24 85*5 'ireful . none 11-6 20-54 171*2 35 202 10*73 9*29 400* 88*56 4*79 *88 1*21 4*88 88*23 rd. little 12-4 5*26 153*3 22 205 9*43 9*23 488*75 71*08 4*88 lf'87 *95 1*37 3*85 65*2 rd. little 28*6 adhes. 9*89 166*3 17 209 9*64 9*22 507*5 84*25 4*15 5*58 *73 *86 4*43 85*1 rd. little 36- 9*07 161*2 30 202 9*.58 9*19 399*5 87*18 5*06 2*53 •86 1*33 3*04 72*94 luch none 34*70 adhes. 17*63 158* 105 190 9*07 8*97 344*16 87*71 4*34 1*58 1*05 1*75 3*57 82*0 f’ * little none 6*57 157*1 87 162 8*94 464*3 87*68 4*89 3*39 1*31 *09 2*64 79*8 fenstant . much 18* adhes. 5*29 155*7 22 199 9*11 8*92 421*25 82*75 5*31 4*64 1*04 *95 5*31 67*1 w. much 66*4 1104 163*3 25 203 9*2 8*86 373*22 85*46 4*20 2*44 1*07 *29 6*54 83*69 vrd. ireful . 54*3 7-36 183*1 23 218 8*84 486*86 75*15 4*93 5*04 1*07 2*85 10*96 62*5 little 80* 10*47 155*8 62 198 8*98 8*72 381*5 88*72 4*50 3*24 *18 3*36 82*5 rd. much 38*5 7-8 141*5 28 215 9*38 8*70 379*80 82**25 5*84; 3*58 1*11 1*22 6* 68*8 ireful . little 23*3 5*44 148*4 27 205 8*82 8*42 404*16 78*36 5*59 5*58 1*86 3*01 5*6 65*6 ttle much 10*7 5*12 151*8 17 198 8*56 8*36 435*83 77*87 5*09 9*52 •57 2*73 4*22 55*4 '.luch 1 considbl. 30*1 adhes. 4*75 150* 10 209 8*19 8*08 492*5 79*09 5*20 8*34 •66 2*41 4*30 58*6 rd. considbl. 39*5 7*78 180*7 22 205 8*34 8* 406*41 73*84 5*14 8*29 1-47 2*34 8*92 56*0 ttle much 19*5 5-6 147*5’ 17 189 7*91 7*85 441*66 78*13 5*53 8*02 *54 1*88 5*90 56*2 rd. little 38* adhes. 5*92 144*6 23 198 7*88 7' 68 397*5 77*98 4*39 8*55 *57 *96 7*55 62*5 rd. much 25*9 9*54 150*5 32 193 7*75 7*53 347*44 74*70 4*79, 3*60 1*28 •91 14*72 63*1 onstant . much 15* 12*63 137*3 17 207 8*04 7*47 *250*4 80*70 5*66 4*38 1*35 2*39 5*52 64*8 lird. mod. 28*6 27*7 152*6 127 162 7*4 6*36 247*24 85*52 3*72 4*55 *12 6*09 35*0 112 l^EWCASTLE COALS Table No. 24. — comparative cost, mechanical, combus OF NINETEEN VARIETIES OF THE NEWCASTLE NAME OF COAL. COST, per ton, at the MECHANICAL STRUCTURE. combustible s 4^ o p. 13 'p ■p o' fc § u Q !» P P cq r cakes Willington 6s. 42*1 53*2 1*11 43* difficultly ordinary . i and Y L obs. J ( cakes ■) Andrews’ House, Tanfield * . 5s. 6d. 42*99 52*1 6*58 easily < and y (. obs. J ,, ,, Coke 74*66 30* strong . r cakes *) Bowden Close 6s. 44*26 50*6 1*33 38*5 ordinary . ord. < and > (. obs. J ? cakes ") Haswell Wallsend 9s. 3d. 47*25 47*4 4*08 73* ord. ord. < and > (. obs. J Newcastle Hartley 7s. 44*35 50*5 1*38 78*5 diff. strong . Hedley’s Hartley 43*07 52* 1*46 85*5 easily quick slowly Bates West Hartley . 8s. 44*13 50*8 9*28 69*5 ord. mod. qk. mod. free West Hartley Main . 7s. to 7s.6d. 45*80 48*9 6*76 79* easily ord. rapidly . Buddie’s West Hartley 8s. 44*09 50*6 7*24 80* ord. mod. qk. freely Hasting’s Hartley 7s. 6d. 46*18 48*5 7*88 75*5 easily ord. freely Carr’s Hartley 7s. 6d. 46*86 47*8 5*60 77*5 easily ord. mod. Davison’s West Hartley 7s. 6d. 46*96 47*7 6*19 76*5 easily ord. freely North Percy Hartley . 8s. 45*62 49*1 8*41 60- easily ord. freely r frpAlv Haswell Coal Company’s") 8s. 45*25 49*5 1*14 79*5 easily > . ord. I iiccij 1 for a > Steamboat Wallsend J 1 time ) Derwentwater Hartley 6s. 6d. 46*44 50*4 12*52 63*5 easily ord. rapid Broom Hill 3s. 4d. 42*67 52*5 9*31 65*7 easily mod. qk. J ClUil 1 (. flame J Original Hartley . 7s. 6d. 45*62 49*1 8*11 80- easily ord. rapidly . Cowpenand Sidney’s Hartley 7s. 46*76 47*9 10*17 |74. easily ord. freely * 1 lb. of Coals with ordinary draught evaporated 9’39 lbs. at the rate of 11b. ,, uneven draught ,, 9*91 lbs. ,, 11b. of Coke „ ,, 7-91 lbs. ,, Newcastle Coals are said to have been first mined or dug,” during the 351*2 lbs. per hour. 526*3 lbs. ,, 449*3 lbs. reign of Henry III. in 1280. NEWCASTLE COALS, 113 ^BLE, EVAPORATIVE, COKING, AND CHEMICAL {STRICT COALS AND ONE SAMPLE OF COKE. CHARACTERS lARACTERISTICS. EVAPORATIVE VALUE. CHEMICAL COMPOSITION. t/2 • Water evapo- Steam rated from 212° C/2 <3 Calorific Value of 5 gra in Melting Lead— graii raised by lib. of Coals. 1 Hydrogen— per cent, 4^ 'a Attention require Smoke. 'a <1 c . E w ft 1 6 1 Residue of Clinkers, . 1 Cinders, and Soot — pc 1 In Time— mean. 1 From temp, of Fah. j 1 Power of— lbs. Realized— lb s . Rate of, per hour- lbs. j Carbon— per cen j Oxygen— per cei 1 Nitrogen— per ce 1 Sulphur— per ce j Ashes— per cen Coke— per ceni I'lstant . much 7' non ad. 5-61 156-5 20 206 10-16 9-95 86-81 4-96 5-22 1-05 •88 1-08 ,72-19 reful . much 3-2 4-5 155-9 40 195 9-8* (9-39 9-91 351-21 526-3 85-58 5-31 4-39 1-26 1-32 2-14 65’13 25-6 5-4 45 203 l7-91 449-2J istant . much 6*6 5-53 158-5 28 203 9-67 9-38 84-92 4-53 6-66 •96 •65 2-28 69-69 1 ich do. & soot 3*5 4*77 157-5 28 199 9-07 8-87 411-66 83.47 6-68 8-17 1-42 •06 •20 62-7 reful . much 17*0 non ad. 8*07 159-3 30 202 8-65 8-23 308- 81-81 5-5 2-58 1-28 1-69 7-14 64-61 •istant . 14-4 11-89 151-8 33 180 8-71 8-16 300-8 80-26 5-28 2-40 1-16 1-78 9-12 72-31 ' cle much 1*4 4-48 144-6 27 202 8-26 8-04 406-8 80-61 5-26 6-51 1-52 1-85 4-25 59-20 1. much 2-8 4-40 151-8 17 208 8-05 7-87:457-5 81-85 5-29 7-53 1-64 1-13 2-51 ■ tie much 5-9 4.82 147-7 35 202 8-01 7-82 413-3 80-75 5-04 7-86 1-46 1-04 3-85 reful . little 1-7 4-59 ' 142-8 20 201 7-96 7-77 404-5 82-21 5-42 6-44 1-61 1-35 2-y4 3t)-b nsider. much 5*0 non ad. 5-76 154-5 28 200 8-13 7-71 344-3 79-83 5-11 7-86 111 •82 5-21 eu'tws -tie consid. . 21 4-47 150-6 23 207 7-83 7-61 402-9 83-26 5-31 2-50 1-72 1-38 5-84 59-4'2 )reful . consid. . 7*8 non ad. 4-86 1 145-5 28 203 7-72 7‘57|423-5 80-03 5-08 . 9-91 -98 •78 3-22 57-18 1 , nstant . much 9-8 10-45 144- 38 184 : 7-85 7-48 291-8 83-71 5-30 1 2-79 1-06 1-21 5 93 61-38 {tie much 28-3 6-33 1 145-5 40 202 ; 7-66 7-42'451-1 78-01 4-74 10-31 1-84 1-37 3-7354-83 ich little 5- 3-23 1 126-6 44 208 1 7-66 7-3 397-7« ;81-7 6-17 4-37 1-84 2-85 3-0759-2 tie much 10-1 4-27 ' 133-1 66 155 > 6-98 6-82 428-4 81-18 i 5-56 ; 8-03 -72 1-44 3-07 58-22 1. much 3-7 5-6£ ► 143-3 27 7-02 ; 6-79350-4 82-2 5.10 1 7-97 1-69 •71 2-33|58-59 F The duty paid on coals and coke last year was ,£251,547 11s. 7«?., of this £175,91 15s. 6(Z. was for the rt of London, and principally on “ sea-borne” or Newcastle coal. The railway dues for the rest ot the lited Kingdom was only £8363 9s. 3c?. 114 IxAIfCASHIEE COALS, Table No. 25. — comparative cost, mechanical, combus TWENTY-EIGHT VARIE lanca COST, per ton, at the MECHANICAL STRUCTURE. COMBUSTIBLE jQ m i»r O o g o "S c o o NAME OF COAL. a 'B cs '5 m o o 1 o Sc o ^ Light. o' (U Burns u - (. time J clear Moss Hall, Pemberton, 4-ft. 6s. 47-35 47-3 3-32 71-5 easily . ord. r freely) Haydock, Higher Florida . 45*25 49-5 6-12 74- easily . ord. for a > 1 time J clear . 1 Ince Hall, Pemberton, 4-ft. . 6s. 8s 6d to 9s 3d 43-24 51-8 4-86 74-5 readily . ord. Blackbrook, Little Delf 6s. to 7s. 43-92 51- 5-58 61-5 easily . ord. freely . | King , . . . 8s. 6d. 15s. 44-09 50-8 2-84 78-5 easily . mod. qk. rapidly . | Rushy Park Mine 7s. 47-65 47- 11-66 67* easily . ord. clear . ii Blackbrook, Rusby Park 6s. to 7s. 40-5 55-3 5-90 80 5 easily . ord. freely . i Johnsons & Worthingtons, I Rushy Park . . . j 44-8 50- 7-15 69- easily . ord. clear Laffak, Rushy Park . * . 7s 6d. 42-58 52-6 6"24 75-5 easily . ord. clear Balcarres, Haigh Yard 6s. 9s. 44-13 50-8 2-69 80- easily . ord. steadily . (»| Haydock, Florida Vein 46-66 48-0 6-61 81-5 easily . ord. (. time J Wigan, 4-ft. 5s. 6d. to 6s. 9s. to 9s. 6d. 41-94 53-4 2-69 75- easily . ord. rapidly . r freely j Ince Hall, Pemberton, 5-ft. . 5s. 6d. 8s. 43-24 51-8 4-75 71-5 easily . strong . < for a >- L time J Cannel (Wigan) 10s. to 12s. 14s. to 18s. 46-37 48-3 1-01 95- easily . ord. freely . J i»; ( time J Ince Hall Cos. Furnace Vein 5s. 6d. 7s. 6d. to 8s. 45-43 49-3 5-33 71-5 easily . ord. r stead.-) Balcarres, Lindsay 6s. 8d. 43-83 51-1 6-47 70- easily . quick < for a [■ Caldwell &' Thompsons, 1 Rushy Park . . . J 5s. 6d. to 7s. 8s. to 9s. 6d. 47*15 47-5 4-97 76- easily . ord. (. time J clear . i Balcarres, 5-ft. 6s. 8d. 45-71 49- 7-12 44-5 easily . ord. freely r freely) Moss Hall, Pemberton, 5-ft. 5s. 46-37 48-3 3-69 78-5 easily . ord. 4 for a > L time J r freely) 4 for a > 1 Moss Hall Cos. New Mine . 5s. 46.28 48-4 6-76 76-5 easily . ord. 1. time J j Caldwell & Thompsons, I Higher Delf . . . j 5s.6d.to 7s. 8s. to 9s. 6d. 46-28 48-4 0-98 77- easily . consid. . r clear •) , 4 for a S (. time J Johnsons & Worthingtons) Sir John . . . ) 6s. 9s. 43-41 51-6 4-62 82- diff. . strong . slowly . LANCASIIIIIE COALS 115 "IBLE, EVAPORATIVE, COKING, AND CHEMICAL QUALITIES OF "lES OF LANCASHIRE COALS. HIRE. :haracteristtcs. EVAPORATIVE VALUE. CHEMICAL COMPOSITION. qT > CO , C w Steam Water evapo- rated from 212° '6 3.S raised by lib. of Coals. P 4J U ‘3 <1 ,P 1 P (U w P D (J 0 0 0 P P o' .2 g Smoke. , X 0 Nitrogen— per u ft i p Ph P cc Ashes— per c 0 u f 0 0 ■rd. . much . •107 adhes. 162'5 22 204 9'55 9'47 487'29 82*61 5'86 7.44 1-76 •8 1'53 64- auch . much . 9*6 146'6 13' 197 9'26 9' 13 532'91 79'71 5'16 10'65 •54 •52 3'42 58-1 rd. much . 11*0 adhes. 5 '68 147'0 18 205 9'09 8'83 454'! 83'54 5'24 5'87 '98 1-05 3'32 62-89 •rd. much . 10-8 3'74 147'9 28 192 9'00 8'81 500'8 82'01 5'55 5'28 1-68 1'43 4'05 57-84 ird. much . 12' 2 non ad. 4'9 150'2 13 205 8'78 461'25 80'78 6'23 7'53 1-30 1'82 2'34 60-6 auch . much . 7*8 adhes. 3'39 149' 12 209 8'91 8'74 461-66 77'65 5'53 10'91 •50 I'73 3-68 59-4 ird. much . 7‘1 adhes. 3' 39 142'5 22 204 8'65 8'52 480* 75'53 4'82 7'98 2-05 3-04 6-58 55-7 auch . much . 13*2 3'62 148'6 9 210 8'49 8'39 467'5 77'33 5'56 12'02 I'OI 1'03 3-05 51-1 ittle . consid. 2-1 3'52 144'3 28 193 8'45 8'34 497'39 77'01 3'93 5 '52 I '40 1-05 1-09 57-1 areful . much . none 3'55 143'4 33 185 8' 55 8'29 440'4 82'7 5'55 4-89 1-48 1'07 4'31 58-48 areful . much . 47' 1 adhes. 3'55 136'4 22 •203 8'35 8'17 395'41 73'66 5'30 9'C6 1-68 ]'58 8'72 62-4 rd. consid. 2'7 3'14 i44'9 23 193 8'35 8'08 419'1 77'76 5'23 8-99 1-32 I'Ol 5'69 56-66 : areful. little . 2'1 adhes. 2'77 151'8 20 198 8'26 8'02 481 '2 81-16 5'99 7-20 1-35 1'62 2-68 58-10 )rd. much . 8'6 3'64 144' 5 28 199 8*16 8'01 454'5 79'5 5'15 9-24 1-21 2-71 2-19 57-52 )rd. much . o'l 3'78 134'() 22 203 8'16 7'98 435' 80'47 5'72 8-33 1-27 1-39 2-82 56-26 much . 26'4 adhes. 8'34 140'8 23 207 8'23 7'9 398'3 82'26 5'47 5-64 1-25 1'48 3'90 66'09 auch . much . 9' 3'97 146'3 12 209 8'97 7'83 422'5 77-49 5'50 12-84 1-27 '88 2-02 54-4 ird. much . 37'6 7'98 150'1 20 207 8'05 7'77 414'79 78-86 5'29 9-57 '86 1-19 4'23 60- auch . consid. 20'4 adhes. 8'74 143' 7 23 208 7' 95 7'72 495'2 68'72 4-76 18-63 2-20 1-35 14'34 56-5 areful . much . 21 '1 adhes. 7'84 148'7 20 194 8'06 7'70 381' 1 79'23 6'08 7-24 1-18 1-43 4'84 60'33 ;areful. much . 25'3 adhes. 7'40 143' 13 211 7'84 7-47 435'21 74'74 5'71 13-52 1-53 •96 4'04 58'4 >rd. much . 22' 3 4'93 131' 25 203 7'58 7'44 431'5 83'9 5'66 5-53 I'40 1'5I 2-00 57-84 ittle . consid. 5'1 2'38 147' 1 22 203 7*43 7'34 449'79 76' 17 5'46 14-87 I'09 •91 1'50 58'7 >rd. much . 21'8 4' 77 129'8 20 7'35 7"21 489'5 74'21 5'03 8-69 •77 2'09 9'21 55'90 nuch . much . 31'9 adhes. 6'35 137'4 20 202 7'29 7'13 417' 18 76'16 5'35 10-13 1-29 1'05 6-02 56' 1 34'2 adhes. 5 '86 135' 1 23 204 7'16 7-04 422'08 ' 77'50 4'84 12-16 '98 1'36 3-16 57-7 nuch . much » 38'6 adhes. 5 '85 141'8 40 188 6'94 6' 85 484'28 1 75'40 4'83 19-98 1-41 2-43 5'95 54-2 nuch 34'4 9'42 119' 22 209 6'62 6'32 362'7 72'86 4'98 8-15 1-07 1'54 11-4 56-15 116 DERBYSHIRE, SCOTCH. Table No. 26. comparative cost, mechanical, combustibl VARIETIES OF DERBYSHIRE, EIGHT OF SCOTCH COALS, SI NAME OF COAL. COST, per ton, at the MECHANICAL STRUCTURE. combustib: N earest Sea port. 1 Bulk per ton, cubic feet. 1 1 Weight per cubic feet— lbs. 1 Weight of Water in Coals, 1 per cent. Cohesion of large Coals, ' per cent. Light. Draught required. Burns. Earl Fitz william’s Elsecar . 5s. 9d. 47*45 47*2 4*83 77* easily mod. freely Hoyland & Cos. Elsecar 5s. 9d. 46*47 48*2 3*72 82*5 easily mod. qk. . freely Earl Fitz william’s Park Gate 47*65 47* 3*08 78* easily mod. qk. freely B utterly Cos. Portland 6s.:9d. 47*55 47*1 7*36 89* easily mod. qk. 1 free Butterly Cos. Longley 6s. 46*86 47*8 3*55 84*5 easily 1 free Staveley . . . . 9s. 44*88 49*9 8*54 88*5 easily ord. freely Loscoe, Soft . 5s. to 7s. 50*0 44*8 9*76 62* readily , ord. r freely < for a L time Loscoe, Hard . , 5s. to 7s. 48*8 45*9 86* readily . ord, • . C freely ^ for a (. time SCO Elgin Wallsend 41*02 54*6 2*49 64- easily ord. freely Wellewood 8s. 6d. 42*58 52*6 2*77 80* easily ord. freely Dalkeith Coronation . 43*36 51*66 5*3 88*2 easily ord. freely Kilmarnock Shevington 6s. 50*1144*7 7*76 83*5 easily ord. treely Fordel Splint . 9s. 40*72 55*0 8*4 63* easily ord . stg. flan Grangemouth , 9s. 40*1354*25 6*42 69*7 easily ord. mod. Eglinton 7s. 4d. 43*07,32*0 10*02 79*5 easily ord. rapid Dalkieth Jewel 44*98j49*8 9*7 85*7 easily ord. freely ] VAR Slievardagh Irish Anthracite . 20s. to 25. 35*66 62*8 4*93 74* ( difficultly ! strong . ( clear Coleshill Co.’s Bagilt Main . 7s. 45*16 49*6 5*50 79. ( sasily . < ord . . ] freely Ewloe . . . . 44*44 50*4 6*83 84* ( easily . < 3 uick . ( clear Ibstock . . . 7s. 6d. 47*35 47.3 1*12 62* < sasily . ( iuick . ( clear Forest of Dean (Lydney). 10s. to 11s. 41*14 1 54*44 2*78 55- ( sasily . i nod. . i smoky Conception Bay (Chili) 13*52 ( sasily . ( ord. . 1 freely P ATENi Warlich’s Patent Fuel 32*44 1 r59*05 •92 s lowly . c )rd, . r nod. Livingstone’s Steam Fuel . 34*14 ( 55*6 1*39 lifficultly c )rd. . s lowly Lyon’s Patent Fuel . 36*66 ( 31*1 1*91 r nod. Wylam’s Patent Fuel 34*41 ( 35*08 1*38 r eadily . c [uick . f reely Bell’s Patent Fuel 34*30 ( 33*3 *9 s lowly . c >rd. . c ►rd. Holland and Green’s 34*56 ( 34*8 2*18 e lasily f freely fora L time , AND OTHER COALS 117 APORATIYE, COKING, AND CHEMICAL PROPERTIES OF EIGHT HER VARIETIES, AND SIX VARIETIES OF PATENT FUEL. [RE. > — — ARACTERISTICS. Calorific Value of 5 grains in Melting Lead— grains. EVAPORATIVE VALUE. CHEMICAL COMPOSITION. Attention required . Smoke. Clinkers, per ton, Adhesive, lbs. Residue of Clinkers, Ashes, Cinders, and Soot — per cent. Steam raised Water evapo- rated from 212° byl lb. of Coals. 1 Carbon— per cent. 1 Hydrogen— per cent. 1 Oxygen— per cent. Nitrogen— per cent. Sulphur— per cent. Ashes —per cent. Coke— per cent. | 1 In Time— mean. 1 1 From temp, of Fah. j 1 Power of— lbs. 1 Realized— lbs. Rate of, per hour— lbs. ch . 6-6 .5*95 150*5 23 198 8*78 8*52 412-7 81*93 4*85 8*58 1*27 •91 2*46 61*6 2h . much 1-7 7*9 148*6 23 197 8*43 8*07 372*91 80*05 4*93 8*99 1*24 1*06 3*73 62*5 ch . none 7*60 150*6 22 199 8*24 7*92 393*75 80*07 4*92 9*95 2*15 1-11 1*80 61*7 jful . much 10*3 non ad. 4*39 155*2 22 199 8*04 7*92 487*08 80*41 4*65 11*26 1*59 •86 1*23 60*9 iful . much 10-0 6*48 150* 15 209 7*98 7*8 398*69 77*97 5*58 9*86 •80 1*14 4*65 54*9 much 12-6 4*78 140*4 22 207 7*40 7*26 466*2 79*85 4*84 10*96 1*23 •72 2*40 57*8 it much 8*4 adhes. 3*36 140*2 22 208 7*99 6*88 490*06 77*49 4*861 2*41 1=64 1*30 2*03 52-8 it much 8*5 adhes. 4*64 147*9 18 208 6*32 431*42 e consid. . 14*5 4*73 145*3 28 203 8*67 8*46|435*77 76*09 5*22 5*05 1*41 1*53 10-70, 58*45 e much 28*5 4*50 142*4 35 181 8*39 8-24l438*5 81*36 6*28 6*37 1*53 1*57 2*89,59*15 e little 62*2 5*9 122*8 30 180 7*86 7*711370*08 76*94 5-2 14*37 trace *38 3*1053*5 ful . much 6*4 3*42 151*6 17 202 7*82 7*66 470*83 79*82 5*82 11*31 *94 *86 1*25 49*3 e consid. . 3* 2*86 145*0 40 176 7*69 7*56 464*98 79*58 5*5 8*33 1*13 1*46 4*0 52*03 little 16*4 5*'26 142*4 28 208 7*91 7*40 380*4 79*85 5*23 8*58 1*35 1*42 3*52i56*6 much 82* non ad. 4*03 121*6 33 186 7*48 7*37 406*2 80*08 6*5 8*05 1*55 1*38 2*44 54*94 e httle 59*5 3*92 132*1 40 193 7*1 7*08 355*18 74*55 5*14 15*51 •10 •33 4*3749*8 JS. eful . none 17*9 7*25 150*5 110 150 10*49 9*85 473*18 80*03 2*3 in ash. •23 •76 10*8 1 90-1 mod. 5*7 3*92 152* 28 197 8*5 8*33 461*25 88*48 5*62 *86 2*02 1*36 1*62 55*8 2 ful mod. 4*4 4*72 135*6 17 208 7*16 7*02 363*95 80*97 4*96 8*20 1*1 1*4 3*37 54*5 2 ful . little 14*1 non ad. 4*10 125*5 20 206 7*02 6*91 454*16 74*79 4*83 11*88 *88 1*45 5*9950*8 much 2*45 4*06 129*7 20 218 8*98 8*52 487*19 eful . much 44*5 ad. 8*48 128*1 30 208 5*96 5*72 425* fELS. eful . little 29*6 6*79 157*5 30 203 10*60 10*36 457*84 90=02 5*56 in ash. trace 1-62 2*91 85*1 ich . little 28*2 10*95 162*7 33 194 10*57 10*03 483*95 86-07 4*13 2*03 1*80 1*45 4*45 ich much 38*7 6*06 156*9 38 189 9*77 9*58 409*1 86*36 4*56 2.07 1*06 1*29 4*66 1. mod. 59*5 7*27 144*1 35 199 9*74 8*92 418*89 79*91 5*69 6*63 1*68 1*25 4*84 65*8 at consid. . 76*1 6*7 142*6 37 ■201 8*65 8*53 549*11 87*88 5*22 0*42 •81 •71 4*96 71*7 ich consid. . 87*6 12=55 118*4 22 204 7*86 7*59 470*0 70*14 4*65 1*15 13*73 Table No. 27. 118 ATERAaE QUALITIES OF VABIOUS COALS. O l^i 2d^ Ph*^ ’r> hJ . Op^ . wp ^Ph Coke per cent. 72'G 60-67 60-22 54-22 59-22 Ashes per cent. 4-91 3*77 4-88 4-03 2-65 Sulphur per cent. 1-43 1-24 1-44 i-11 1*01 Nitro- gen per cent. 0- 98 1*35 1- 930 1-0 1*41 j Oxygen per cent. 4-15 5*69 9-53 9-69 10*28 Hydro- gen per cent. 4*79 5*31 5*32 5*61 4*94 Carbon per cent. 00 (M CO QO 1 O O CO (M CO 05 QO 00 !>. 1:^ * Sulphur per cent. 1*42 0*94 1-42 1*45 1-01 1 Per hour. lbs. 448*2 411*1 447-6 431*4 432*7 By 1 lb. of coals, lbs. 9*05 8-37 7-94 7*7 7-58 Cohe- sion per cwt. of large coals. 6-09 67-5 lO CO w 6-08 Weight of 1 cub. foot, lbs. CO iO 49*8 49-7 o iO Tti ■ 'Vi lO 05 »o 4 sJ o . w CO rH 04 >*o iO w pq o Oao CD rC3 bO “ S ^ c3 O ^ S3 O m t'-xtiOCMCO^'^'^OCOTOOOi'CDTOOii— ITOCM'^COCM Qi S O S CO'^^ iOCTO'COTO'OCO^^OCOiOOTOb- 'rtHlO'COO'pVOXp'rfC-rriT— l005l>»OiCOOit;-OTOT— ICOO cbi*^'i>iox^^J^i^^H»ol>•Oicbcsooo^(^:)TO'cbl>.^>. o ^ O (B rO c> O ft lo t^lr^'^CMiOlr^vo^'rH^O co CO‘01>»0(M^CMT^CM‘P'^COOrH'^iO‘OOiG^(^Ci(M cbcO^CMOi^CO^HciiOCMiOT^CMr^Oi'^cbcOOiOOO TOTOTOOiOOTOTOOiTOTOTOTOTOTOTOlr^t^l-^TOTOTOOi ^ r. .2 S 8 “ v5>.Sf^ § • • g • • • • a -rt § 2t>^ s ^ '3 2 ^ s rt s • &- a ^ • • * •'H |a o .11 ^ g P PHP^ g.M o ^ j3 I |fc I I ^'^.^iSll . Is I ' "is'iii 3 ' oo) a doo^.S o H p:; pq TO :e. — A ll tlie Tarieties contain more or less of sulphur. In the anthracite running from "48 to '91 per cent, of the ashes and in the bituminous from 2-6 to 27 per cent. The general characteristics of each kind are for anthracite, ecomomy ol space, freedom from smoke and cleanliness ; for bituminous, free combustion, smokiness, and less durability than the anthracite. HOUSEHOLD WASTE OF HEAT. 121 The ratio of carbon in coals, it is thus seen, varies consi- derably ; so also does the quantity of hydrogen. Generally, bituminous coals yield less carbon than anthracite coals, but more hydrogen. Bitumen renders coals easily ignited and smoky, whilst it gives them that caking quality so much appreciated for domestic use in London, by melting the coals together, thereby closing the top of the hre, and, by preventing the heat being so rapidly carried up the chim- ney, causes it to radiate more into the apartment. It also at the same time tends to prevent light ashes flying about, an evil so much complained of with less bituminous coals. The waste of heat which takes place in ordinary fires, by about two-thirds of it passing up the chimney, is well known ; yet how few fire-places are constructed otherwise than to increase this waste, or draught,’^ as it is called. A better class of radiating fire-places, at once elegant and econo- mical, seems still to be a desideratum, where custom and prejudice hold so firm a sway as to prevent attention to either comfort or cost. • Dr. Arnott’s experiments showed that full one-half the heat evolved was carried directly up the chimney; a large portion of that radiated outwards was immediately drawn back into the chimney, and only a small proportion of the whole into the apartment. Many of the open burning coals contain more carbon, and give out more heat by about 10 per cent, in steam-boiler furnaces than the Newcastle caking coals. Anthracite contains more carbon than bituminous coals, is more clean, by burning nearly free from smoke, and is now variously used. The following is the average range of variation in 100 lbs. of each fuel : G 122 GENERAL USE OF COAL TABLES. BITUMINOUS COALS. Carbon . . 53 to 88 lbs. in every 100 lbs.' of coals Volatile gases (nitro- gen, oxygen, and hydrogen) . 44 to 10*5 lbs. ,, • Ashes . . 3 to 1*5 „ Total 100 or 100 ANTHRACITE. Carbon . . 75 to 94 lbs. in every 100 lbs. of coals Volatile gases (nitro- gen, oxygen, and hydrogen) . . 14 to 1’5 lbs. ,, Ashes . . 11 to 4*5 ,, Total 100 or 100 The coal tables supply a detailed analysis of each of the numerous varieties therein named. Not only to coal-mine proprietors and engineers, but also to other coal consumers, will these tables be useful, either for comparison or selection in the railway-extended and extending field of choice and competition. For instance, London, besides its usual supply of sea-borne ” coals, now commands Newcastle, Yorkshire, and Derbyshire coals, cheaply supplied by the Great Northern Railway ; the Lan- cashire coals by the London and North Western Railway ; and will also shortly command, equally cheap, nearly all the tabulated varieties of the superior Welsh coals by the Great Western Railway. These several sources of supply embrace coals of every COALS, AND GAS IN COALS. 123 variety, and the tables supply the correct general character of each coal-lield and of many individual sorts by name, which can scarcely fail to be useful to a wide circle, either directly interested in steam-engine or household consumption of coals. It may be rem^arked, that for London alone, in 1848, 3,380,786 tons, and in 1849, 3,4/9,189 tons of coals, paid the city duty of 13^^. per ton as brought within the Port-boun- daries either by sea or inland conveyance ; and that during the year ending last July, 271,066 tons of coals were exported from Liverpool, of which 143,037 tons were to the continent of America. The coals in the following countries are thus approximately estimated ; Area, Tons dug In Great Britain : Sq. Miles. in 1845. Bituminous . 8139 1 31,500,000 Anthracite and culm In the United States : 3720 1 Bituminous 133,132 1,750,000 Anthracite . 437 2,650,000 In France . 1719 4,141,600 In Spain . 3408 In Belgium . 518 4,960,000 In Prussia . 3,500,000 In Austria 700,000 The quantity raised now in Great Britain is estimated as about 36 millions of tons, of which about 2 millions are exported, 8 millions consumed in iron-making, and | of a million in making coal gas for general use. In making coal gas for illumination, the quantity of hydro- gen evolved varies from about 5000 to 11,800 cubic feet per ton of coals, and is thus estimated : G 2 124 EVAPORATIVE VALUE OF COALS. Scotch cannel . 11,800 cubic feet of gas Lancashire cannel . 11,600 ?5 Newcastle . 9,600 J J Staffordshire . 6,400 99 Wallsend . 10,300 99 Templemain . 6,200 99 Tenby . 4,200 99 Besides lighting purposes, the heating power of gas is now drawing attention to its domestic economy. Mr. Defries raised the temperature of 45 gallons of water from 50® to 100® Fahr. by 30 cubic feet of gas, at a cost of \\d. Mr. Evans estimates the heating power of 1 cubic foot of Newcastle coal gas as equal to boil off into steam 22 times its own weight of water, and practically boiled off from 12 to 13*6 times its own wei 2 :ht as below : Gas burnt cubic ft. WEIGHT OF GAS. WATER BOILED. Heating power. Ratio. Grs. Spe. gray. lbs. Ratio to gas. 1 206 •416 22 1 205 •413 •4 13*6 — 1 290 •564 •5 12-0 — 1 360 •700 •7 13-6 — Evaporative Value of the Hydrogen in Coals, It has been usual, as previously stated, to regard the heat given out by the combustion of hydrogen as little more than compensating for its production, and that by the quantity of carbon in any fuel its evaporative value was indicated. The following useful table shows the theoretical duty possible by 1 lb. of coals, by the coke in 1 lb. of coals, and by the hy- drogen in lib. of coals, with the total theoretical compared with the realized duty. EVAPORATIVE VALUE OF COALS, 125 Table No. 30. THEORETICAL AND PRACTICAL DUTY OF lib, OF COALS, AND ITS CONSTITUENT PARTS. Water converted or convertible Force or power of into Steam. 11b. of coals Theoretically convertible 1 a S3 ® 53-^ • 9 842 -S4 . NAME OF o fcc w . Practically cc verted by 11b, coals. 7, c3 2'*^ o FUEL. By 11b. ofc Total. o . O i=l -S c; o s;: o £ oSr-l Equal to a 1 raised 1 ft. Practic rt lbs. lbs. lbs. lbs. lbs. lbs. lbs. Graigola 13-563 1-903 11-660 9-35 11*301 7-060-908 10-242-471 Anthra- r J ones, Au- "i cite tbrey, &Co. J 14-593 2-030 12-563 9-46 12-554 7-143-978 11-020-303 Oldcastle Fiery Vien . 14-936 2-890 12-046 8-94 10-601 6-751-285 11-279-329 Ward’s Fiery Vien . 14614 2-542 12-072 9-40 7-098-667 11-036-162 Binea .... 15-093 2-912 12-181 9-94 11-560 7-506-463 11-397*892 Llangenock 14-260 2-519 11-741 8-86 10-599 6-690*871 10-768-829 Pentripoth 14-838 2-649 12-189 8-72 10-873 6-585-116 11-205-322 Pentrefellin 13-787 2*038 11-749 6-36 10-841 4-802*9-28 10-411-630 Powell’s Duffryn 15-092 2-966 12-126 10-149 11-831 7-664-295 11-397 137 Mynydd Newydd 14-904 3-441 11-463 9-52 9-831 7-189-288 11-255-163 Three-quarter Rock\ Vein . . . / 13-106 2-781 10-325 8-84 7-081 6-675*768 9-897*355 Cwm Frood Rock Vein 14-788 3-488 11-300 8-70 8-628 6-570-043 11-167-563 Cwm Nanty Gros 13-932 3-165 10-767 8*42 8-243 6358-593 10 521*131 Resolven 13-971 3-072 10-899 9-53 10-234 7-196-840 10-550-583 Pontypool . 14-295 3-207 11-088 7-47 8-144 5-641-175 10-795-260 Bedwas 14-841 3-766 11*075 9 79 8‘879 7-393-186 11-207-587 Ebbw Vale . 15-635 3*300 12-335 10-21 10-441 7-710-361 11-025T98 Porthmawr Rock Vein 12811 2-548 10-263 7-53 6-647 5-686-485 9-674-577 Coleshill . 12-799 2-654 10-145 8-0 6-468 6041-419 9-665-515 Dalkeith Jewel Seam 12-313 2-071 10-242 7-08 6-239 5-346-655 9-298-499 Dalkeith Coronation . 12-772 2*202 10-570 7-71 6-924 5 822-417 9-645-125 Wallsend Elgin . 13-422 2-968 10-454 8-46 6-560 6-388-800 10-135-991 Fordel Splint 13-817 2-884 10-933 7-56 6-560 5-709-141 10 434-286 Grangemouth 13-692 2-722 10-970 7-40 7-292 5-588-312 10-339-888 Broomhill . 14-863 3-638 11-225 7-30 7-711 5-512-795 11-224-201 Park End, Lydney . 13-257 3-156 10-101 8-52 6-567 6-434*111 10-011-386 Slievardagh (Irish) . 12-482 1-487 10-995 9-85 10-895 7-438-497 9-426-124 Formosa Island . 13-553 2-801 10-752 10-234-919 Borneo (Labuan kind) 10-252 1-388 8-864 7-742-078 „ 3-feet seam 8-756 1-295 7-461 6-612-333 „ 11 » . 11-600 1-948 9-652 8-760-057 Wylam’s Patent Fuel 14-331 3*145 11-186 8-92 8-378 6-736 182 10-822-447 Warlich’s 15-964 3-596 12-368 10-36 11-292 7-823-637 12-955-652 Bell’s . . . . 15-417 3-343 12-074 8-53 9-168 6 441-663 11*642 569 126 EVAPORATIVE INFLUENCE The respective evaporative values are estimated by taking 13268 as the unit of heat in a pound of carbon, and 62470 as the unit of heat in a pound of hydrogen, and dividing by the vaporization heat of 965-7°. The coke value is obtained by subtracting from it the quantity of ashes due to the coals, and considering the remainder as carbon. By this table it is observed that although there are striking exceptions, the work capable of being done by the coke alone is greater generally than that obtained from the coal. A closer examination of the experiment at the Par Consols mine appears, however, to indicate that the hydrogen does ex- ercise a beneficial result on the evaporative powers of the fuel. The quantity of water evaporated was 11*428 lbs. by 1 lb. of coals, and their composition was 84*19 of carbon, 4*19 of hydrogen, 86 of oxygen, 8 of nitrogen, 1*9 of sulphur, and 8*06 of ashes. The water being at 212'^ temperature required only 965*7*° of heat to convert it into steam. Taking Bulong’s values of 13268"° of heat for carbon, and 62470° of heat for hydrogen, in this instance, we can readily compare the theo- retical with the practical effect. Theoretically we have. Carbon = 84* 19 x 13268 lUO ibs. X 965*7 4*19 X 62470 1 1 '567 lbs. of water. and for hydrogen i 00 lbs. X 965*7 -= 2*71 lbs. of water. total theoretical value of 1 lb. of coals = 14*267 or together, carbon = 84*19 x 13268 = 1117032*92 hydrogen= 4*19 x 62470= 261749*30 1378782*22 as the units of heat in 100 lbs. of coals, which being di- vided by the evaporative heat of 965*7*° x 100 lbs. of coals = 14*277 lbs. of water, capable of being evaporated by lib. of these coals. OF HYDROGEN. 127 Practically, 1 lb. of coals evaporated 11 *428 lbs. of water from 212®, or only *139 lbs. less than the theoretical value of carbon, but this 11*428 lbs. was not all the heat actually obtained from the fuel. For it is stated that hy an arrange- ment of water-pipes in the flues, the feed-water was heated to about 212®, by the heat absorbed from the passing gases on their way to the chimney, where their temperature was still 300®. Taking the ordinary temperature of water as 52®, it requires to absorb 160® to raise it to 212°, hence the actual eva- poration of ^ ^ ^965^7 ~ 1 ‘690 lbs. of additional evapora- tive heat from the coals, making 11*894 lbs. as the total heat absorbed, or *327 lbs. more than was possible by the carbon, and 2*37 less than the total theoretic value of 1 lb. of coals. Without considering the 300® of heat still left to escape up the chimney, the beneficial effect of the hydrogen in the evaporative results is quite evident. The Mynydd Newydd coals having a similar large propor- tion of hydrogen (4*28 per cent.), it will be seen by the table that they have a higher practical value than several others pos- sessing more carbon, but less hydrogen. Taking as another example the Aberaman Merthyr coal, containing 90*94 per cent, of carbon, and 4*28 of hydrogen, possessing the highest evaporative value in these tables, or 10*75 lbs. under the experimental boiler : For the Cornish boiler the evaporation would be « 10*75 X ] *1995 = 12*894 lbs., and as before. Carbon 90*94 x 13268 = 1206591*92, or 12*494 lbs. Hydrogen 4*28 x 62470 = 267371*60, or 2*769 lbs. 1473963*52 15*263 lbs. as the 100 X 965*7 theoretic value of 1 lb. of these coals. Taking the absorption of carried heat by the feed-water to 128 MECHANICAL VALUE OF HEAT. be, as before, equal to 160*^ for the quantity evaporated, we have ^ 3 := 1*781 lbs. as its value, 965*7 and 10*75 + 1*781 = 12*531 lbs. or *037 more effect from an inferior boiler than due to the carbon. If the heating values assigned to carbon and hydrogen be correct, it is very gratifying to find so fair an approximation of practice to theory. These examples from experiments made by a Government officer for official purposes only, clearly indicate that the gases evolved during combustion do exercise a beneficial effect in generating steam. Since a deficiency of hydrogen may be made up to some extent by introducing water, it is a reason- able deduction, that the practice we have before referred to is consistent with theory. The last two columns of the table show the practical, me- chanical, and theoretical value of 1 lb. of the respective fuels. It is based on Mr. Joule’s estimate, that the mechanical value of air and of heat equal to raise 1 lb. of water 1 ^ Fah., is 782 lbs. The application is simply by multiplying the number of pounds of water evaporated by the heat of evaporization, in these cases 965*7° and by 782 for the total value. It is, however, right to state that others take only 682 as the me- chanical equivalent of an unit of heat. Taking the Mynydd Newydd as an example, whose practical value is 9*52 lbs., it gives 9*52 x 965*7 x 782 = 7,189,288 lbs., raised 1 foot high. The theoretical value is obtained in a similar manner by taking the ratio of 9*831, instead of 9*52. Heating of the Feed-water, It is not unusual to find a very high value placed upon this practice, by those who have not fully investigated the matter. The last two examples show that in the one case it added 1*69, and in the second case 1*78 lbs. to the evaporative value of the VALUE OF HEATING FEED-WATER. 129 fuel, when the water was heated to 212°. The mistake arises from supposing that only 2 1 2° of heat are required to evaporate steam of atmospheric pressure, whilst by Hegnault’s careful experiments it requires 965*7^ + 212 = 1177*7^. From this is to be deducted the initial temperature of the water, which if taken at 52° leaves 1 125*7° to be imparted in order to con- vert that water into steam. Hence, 1125*7 2 1 2— ^2 7*04 or 14*19 per cent. as the utmost gain. If less than the boiling temperature is attained by such heating then the gain would be proportionally decreased, as shown in the following table : — Table No. 31. Hatio of the Heat applied to Feed-water to the total Heat of Steam of Atmospheric Pressure, or 1177*7° less the Initial Heat of the Water, or say 52° Temperature — 1125*70. Water heated from 52° to Fah. Increase in deg. Fah. Increase per cent, of the heat of Steam. 62 10 •887 72 20 1-77 82 30 2-66 92 40 3-54 102 50 4-43 112 60 5-32 122 70 6-20 132 80 7-09 142 90 7-98 152 100 8-87 162 110 9'75 172 120 10-64 182 130 11-53 192 140 12-41 202 150 13-30 212 160 14-19 130 SECTION II. CHAPTER I. VARIETIES OF STEAM. In its general acceptation, steam is pure water expanded by heat into an invisible vapour, but as water is rarely found pure, the heat which distils it into steam also deposits these impuri- ties. Under the influence of solar heat these deposits are familiar in the immense deltas constantly forming at the mouths of rivers ; and under the influence of ordinary heat, they are familiar in the fur ” deposited in tea kettles, and incrustations in steam boilers. There are several distinct varieties of steam recognised, of which we may enumerate, I. Natural steam, raised by solar heat. II. Spheroidal steam, raised by dropping water on hot metallic surfaces. III. Surcharged steam, raised by heating common steam when not in contact with water. IV. Common steam, raised by ordinary heat. Natural Steam, Natural steam is that raised from the various accumula- tions of water on the earth by solar heat, and is believed to be perfectly analogous to common steam. In a fine day, when solar heat raises natural steam most abundantly it is invisible, so likewise with steam generated in a glass bottle over a spirit lamp, until it comes in contact with the atmosphere. Partial condensation then occurs, and it becomes visible in the form of light fleecy clouds. When the atmosphere is saturated with natural steam, a partial condensation begins to operate, and natural steam becomes visible in the form of clouds, whilst its descent in the shape of mist or rain attests its abundance. NATURAL STEAM. 131 Common steam also assists us to arrive at the probable cause of the beautiful colours which occasionally adorn the floating clouds to the delight of the spectator. Professor Forbes, having accidentally observed that the steam issuing from a locomotive safety valve changed colour when seen between the observer and the sun, made a series of experiments on the subject at Glasgow, in 1 839, which con- firmed his accidental discovery. He first observed that at the immediate edge of the safety valve the issuing steam was invi- sible, but at a short distance from the edge of the valve it had a red appearance, similar to looking at the sun through smoked glass, or the smoky atmosphere common to large cities in pecu- liar states of the atmosphere. This redness gradually faded away until the steam resembled the ordinary clouds. The experiments confirmed the original observation, and led him to conclude, that, to the rays of solar light passing through natural steam in a state of partial condensation, were due the gorgeous colouring of the clouds pleasingly adorning our evening skies, and frequently calling forth the artist’s skill in delineating sunset.” The stupendous operations performed by the Great Creator with natural steam have long arrested the scrutinizing atten- tion of philosophers, geologists, and meteorologists, and are thus referred to by the celebrated musician Haydn, in his Oratorio of the Creation, as among the leading phenomena of nature — Now from the floods the steams ascend to form reviving showers, The desolating hail, the light, the fleecy snow. ^ ^ :jc Ye mighty elements, by whose power Are ceaseless changes made : Ye mists and vapours that now rise From hill or steaming lake.^^ The mighty influence, therefore, of solar heat in raising 132 NATURAL EVAPORATION. steam from rivers, lakes, and oceans, to be condensed by the cold of the upper regions, and return to the earth again in rain, hail, or snow, becomes obvious in the succession of atmo- spheric changes. Natural evaporation is also greatly influenced by the motion of the air, as shown in the following experimental table by Dalton, giving the evaporation from a vessel 6 inches in dia- meter, exposed to the atmosphere. Table No. 32. RATE OE NATURAL EVAPORATION OE WATER. Temp. In. Mer. Calm. Grains. Gentle Breeze. Grains. Brisk Wind. Grains. 40 •263 105 1-35 1-65 42 •283 1 13 1-45 1-78 44 •305 1-22 1-57 1-92 46 •327 1-31 1-68 206 48 •351 1-40 1-80 2-20 50 •375 1-50 1-92 2-36 52 •401 1-60 2-06 2-51 54 •429 1-71 220 2-69 56 •458 1*83 2-35 2-83 58 •490 1-96 2-52 3-08 60 •524 2T0 2-70 3-30 Ordinary evaporation is also increased by the quantity of vapour in the air, which increase may be thus determined : Ascertain the dew point, or that temperature when the vapour in the air will begin to condense on a colder body, such as a glass containing a cooling mixture. As soon as this dew or con- densing point of the natural steam in the air is found, say at 42°, and the temperature of the air at rest is 58°, the natural steam in the air would be 1*96 by the table, from which NATURAL EVAPORATION. 133 deduct the vapour for the dew point of 42°= M3, leaving *83 grains per minute as the ratio of evaporation from a surface of very nearly 29 square inches. The following is one of Daniell’s experiments on this point : The temperature of a room was 45° and the dew point 39°, when a fire was lighted until the temperature rose to 55°, but the dew point remained the same. A party of eight persons then occupied the room for several hours with the fire kept up, when the temperature ro^e to 58° and the dew point to 52°, hence a considerable accumulation of vapour had taken place, which should have been carried off if the apartment had been properly ventilated. By these simple means the relative states of the air of a room may be ascertained and improved. Some definite idea will be formed of the magnitude of natural evaporation when it is considered that it must neces- sarily be equal to the total supplies of water from all sources, or otherwise another deluge would result from a lesser eva- poration. The Mississippi is estimated to supply 1,110,600 millions of cubic feet of water annually, and to deposit unevaporable matter equal to foVo of its volume, or 3702 millions of cubic feet. The Ganges is estimated to deposit unevaporable matter equal to 6,000,000 cubic feet, or 355,000,000 of tons annually. Other rivers and streams are also daily carrying the crust of the pre- sent earth to the ocean, in greater or lesser quantities, leading to the opinion that in the lapse of time the present relative position of dry land and water will be changed, when the Bucklands, the Lyells, and the Mantells of other ages will be investigating the geological character of the present deposits. That this idea is not without a reasonable basis may be inferred, since the exist- ing delta and plain formed by the deposit of the Mississippi forms an area of 31,200 square miles, or nearly as large as Ireland, which contains 32,512 square miles of surface. Such is an outline of nature’s operations with steam, com- 134 SPHEROIDAL STEAM. pared to which the greatest efforts of man — however consider- able in his sphere — are small indeed, but the vast difference is not more striking than instructive to mankind. Spheroidal Sieam. About 1844 this variety of steam was introduced in France by M. Boutignj, and brought into practice by M. Beauregard, who patented its use in this country in 1848. Although it is not probable that it will come in competition with ordinary steam, either for economy or usefulness, considerable notice was taken of it at the time. It is produced by dropping water in a red-hot metal plate, having an indented surface to prevent its running off the plate. When the water is about 206° tempera- ture it adheres to the plate, and slowly passes off into steam ; it is said of the elasticity due to the temperature of the plate, and not of the water, and this difference of elasticity is the source of the economy claimed by M. Beauregard for his spheroidal steam generators. When the water is of a higher temperature than about 206°, the repellent power of the heat of the plate and sphere of water prevent their contact, and, as may have been seen when a drop of water has fallen on a hot plate, it runs about growing less and less until it disappears altogether, without being converted into steam. It was esti- mated that by this generator the water passed into steam about fifty times slower than by an ordinary boiler, but possessing a force which requires only about one per cent, of the space. The spheroidal generator was tried with a vessel of melted lead, heated to 540°, having a hemispherically indented plati- num bottom plate, on which the water was thrown from a suitable pipe. The results were said to be more economical than with ordinary steam, but this may reasonably be doubted, since it is the real economy of ordinary steam which enables and will still enable it to compete with many ingenious pro- ductions of motive power, where greater expense prevents their STAME. 135 realization in practice. Carbonic-acid gas, air, and o,ther mo- tive agents, can and have been found to be capable of developing great power, but have failed as yet to be so economical as steam, and have fallen into disuse from that cause. Heated Steam or Stame. More recently Mr. Frost, of America, has called attention to the much greater economy of steam when heated between the boiler and cylinder, than when used in the ordinary way. This heated steam he calls stame,” and contends that it is a diiferent vapour produced by different atomic proportions of heat and water than form ordinary steam. Like M. Beaure- gard he also estimates the comparative economy as about 4 to 1 in favour of stame. A short description of his instruc- tive experiments may lead to their further investigation. Fig. No. 25 is a bent glass Fig. 2^. Fig. 2^. Fig. 21. tube closed at the short end, which contains one drop of water at A. Mercury is then admitted to fill the short end, and a part of the long end of the tube con- taining a float and index, a. The pressure on the drop of water was, therefore, the at- mosphere and the mercury in the tube. After being carefully prepared, this eu- diometer was placed in cold water, which was gradually made to boil at 212°, and then slowly saturated with salt till the boiling point w^as stationary at 228° ; the ex- 136 FORCE AND VOLUME OF STAME. pansion being marked, as seen in the diagram at the respective temperatures of the two boiling points. Fig. No. 26 is a tube of a different form, where the drop of water was confined at the bend B, between two columns of mer- cury. The short end was closed, and the long end open. It was then subjected as before to boiling at 228° to determine that volume, and then transferred to a mercurical bath, which was gradually heated to 650°. The float and index marked the vo- lume and the pressure in inches of mercury, whilst a thermo- meter marked the temperature of the bath as it slowly cooled down again. These were carefully noted, and showed much irre- gularity in the rate of expansion, as marked in the diagram. Fig. No. 27 is a repetition of the same experiment in a different tube, having a drop of water at the extremity of the bulbous end E. The expansion was carefully marked at 212° to obtain the atmospheric volume, and it was then transferred to the bath as before, when the cooling showed a similar irre- gularity of expansion as the former experiment. These expe- riments show the rate of expansion of steam in contact with mercury from 212® to 650^ but not in contact with any water. Similar experiments were performed with the same tubes, but using fusible metal and linseed oil to confine the steam, when the rate of expansion was much more uniform, while nearly the same at the extreme pressures. Taking the difference in the specific gravities of the mercury, fusible metal and oil, the ex- treme differences may be considered as due to the difference of pressures. From these experiments it appears that the mercury exer- cised an influence on the rate of expansion by equal incre- ments of heat, not done by the metal or oil. But what more particularly requires to be noticed and further tested is the great increase of volume by increase of heat, with a slow in- crease of elastic force. For whilst the elastic force only in- creased 12*5 inches of mercury, the volume was increased to EXPANSION OF STAME. 137 seven times that of 212°, making a total volume eight times greater than the atmospheric volume of ordinary steam. It has been usual to treat steam as subject to the same laws as air, which expands *00202, or tIo of its volume for each increase of one degree of Fahr.,'but these experiments show an increase of seven volumes for an increase of only 438° of heat. If further carefully conducted experiments confirm these results, then Gay Lussac’s law for permanent gases is not adapted for heated or surcharged steam. As that law pur- ports to commence at 32° when the volume of water is Fig,2S, which at 212° becomes suddenly 1700 times 2 . that volume. Gay Lussac’s law has been applied ^ I ^ to steam, through the 1700 volume, and correction I I I ^ temperature, so that its failure in steam — if failure it prove, may not affect its application to permanent gases, for which it was submitted. The probability that the variation in the respective states of water at 32°, 40°, and 212°, known as ice, water and steam, may in stame not perhaps be governed by a law designed for permanent gases, cannot be remarked without reflections on the Author of that law. Diagram No. 28 shows the results of these experiments collected on a scale of equal parts. The metal was bismuth 5, lead 3, and tin 2, which is fusible at 210°, but on cooling it lost its fluidity so far at 218° as not to be depended upon below that temperature. To test in another way the influence of the pressure of bodies on the generation of steam, when in contact with these bodies, the following experiments were tried : The glass eudiometer. Fig. 29, was filled with boiling water and heated in a bath at 650°, when all the water w^as expelled, and its open end o her- S50 138 PRACTICAL TRIAL OF STAME. metically sealed, leaving only the water due to the steam in the tube. This being condensed, left a vacuum, and the tube being immersed in a vessel of mercury, the sealed end was broken off, when of course the mercury instantly filled the vacuum. On being subjected to heat, the steam showed itself at the usual temperatures. The same pro- cess was repeated with turpentine, but up to its boiling point of 316° no steam appeared. Also with linseed oil, no steam showed itself up to 400° tempera- ture. These experiments indicate that whilst mercury exercises no great influence over minute portions of water passing into steam, yet both turpentine and linseed oil do so to a great extent. The fixity of water when subjected to high tempera- tures, as exemplified in the spheroidal generator, was tested by introducing a small drop of water about one inch below the surface of the linseed oil, with which water does not combine. The glass tube was then slowly heated to 300° but the water remained unevaporated. At 320° it began to decrepitate, and at 340° the concussions led to the close of the experiment to save the tube from being broken, when one-half of the drop of water still remained. Since linseed oil is lighter than water, as *93 to 1, the pressure was less than that of an equal column of water, through which steam rises with rapidity, yet the temperature was equal to that of ordinary steam at 116 lbs. per square inch. To test the results of these experiments practi- cally, twm engines, one having a three-inch, and the other a six-inch piston, giving the respective areas as one to four, were tried publicly, and showed a corresponding gain in favour of stome over steam. They were both supplied with steam from the same boiler, generated by equal quantities of fuel, con- sumed in equal times. The only difference was, that the steam pipe to the large cylinder was carried through the upper part of the furnace in a spiral tube, having a heating Fig. 29 . USEFUL PROPERTIES OF STAME. 139 area of about -t that of the boiler. Measured by one of Morin’s Dynameters the power given out was four times greater from the larger than from the smaller cylinder, indi- cating that the pressure on both cylinders was nearly alike, and that the increase of volume was due to the heat taken up by the steam in passing through the furnace. If this is a fair estimate of the difference, it shows that there is a considerable gain at a small cost ; and that of the theoretical expansion of eight volumes, four were realized in practice, whilst the re- mainder filled the extra pipes and balanced the abstraction of heat again by colder bodies and other resistances. Mr. Frost gives the following comparison of steam and stame, with the effects of the exhausted steam, in baking bread from dough : Pressure. Temperature in Effects on Dough. 1 Atmos. Boiler. Cylinder. Exhaust pipe. Surface. Substance. Steam 6*5 321° 216° Glistening. Tender. Stame 2*5 264° 612° 550° Charred. Hard. This is probably an extreme result, giving 612 — 550, a loss of only 62°. For stame is found to take up and part with heat rapidly to colder bodies, requiring the temperature of the con- ducting pipe and cylinder to be maintained when the heated steam was six times as effective as ordinary steam, although passed through a coil of piping ten times the length of the ordinary steam pipe. From experiments made in France, it is stated that steam heated to 392° does not char wood, that at 482° it is imper- fectly charred, at 572° it is charred brown, and at 662° it makes black charcoal, yielding a greater quantity and better quality of charcoal for making gunpowder than by the ordi- nary process of charring. The French Minister of War advanced 5000 francs for carrying out these experiments, which led to its adoption 140 USEFUL PROPERTIES OF STAME. for making the charcoal at the Esquinede gunpowder mills. The experiments were made similarly to M. Frost’s, by heating ordinary steam in a coil of pipe 8 inches diameter, and 66 feet long. M. Violette states, that at 392° bread can be baked, meat cooked, and other extractive operations successfully ac- complished by stame, for we prefer the more simple name to any compound of surcharged, heated, or anhydrous steam, by all of which names it is occasionally designated. At Stonehouse, Plymouth, Mr. Lee’s patent oven is said to bake superior bread in an atmosphere of stame whose heat is regulated by a thermometer. To numerous visitors of the Crystal Palace, Mr. Perkins, of London, distributed pieces of bread baked in his patent hot water ” or stame oven, by the radiation of the heat through coils of pipes forming shelves for the loaves. The importance of stame is, therefore, not confined to its operations in the steam engine, but extends over a wider field. In America, Frost’s experiments drew the attention of the In- stitute of xlrts and Sciences at New York, who give the follow- ing tabular results of experiments : The steam was got up to 2 1 lbs. pressure, and the engine made 2000 revolutions, which exhausted the steam in the boiler, and the condensed steam raised the temperature of the condensing water from 48° to 62°, or 14°. With the same pressure in the boiler, but heated in passing to the cylinders, when the engine had made 2000 revolutions by stame the pressure in the boiler was raised to 37 lbs., and the water in the condenser from 61° to 70°, or 9°. During the trials the condenser showed a steady vacuum of 12 lbs. For equal volumes, therefore, it appears that the heat was greater in steam than in stame in the ratio of the heat communicated to the condenser, or as 14 to 9 ; and that the less abstraction of heat from the boiler by stame, added the dif- ference between 21 and 37, or 16 lbs. effective pressure to the steam in the boiler, whilst with ordinary'' steam the heat was all expended and could not sustain the pressure. NEW YORK INSTITUTE. 141 Table No. 33. EXPERIMENTS ON STAME BT THE COMMITTEE OF THE ARTS AND SCIENCES INSTITUTE, NEW YORK. At Low Pressure, Temp. Fah. Vol. In. mer. Pressure. In. mer. Actual volume of stame each. 31 OT 0-2 0-1 94 1- 2 2- 115 2 4 8 128 3 6 18 138 4 8 32 150 5 10 50 159 6 12 72 165 7 14 98 172 8 16 128 180 9 18 162 212 10 20 200 At High Pressure. Temp. Fah. Vol. In. mer. Pressure. Atmospheric. In a given vol. In. mer. 212 1 30 1 30 216 2 32 2133 64 228 3 34 3-4 102 450 4 36 4-8 144 600 6 40 7-2 216 650 7-37 42*75 9-8 294 The committee felt satisfied of the importance of these ex- periments, and of the economy of stame if it could he brought into operation, where the temperature of colder bodies would not interfere to abstract the heat before it could be profitably 142 DR. HAYCRAFT ON STAME. Dr. Haycraft, of Greenwich, had also made a number of ex- periments with stame, or, as he designates it, anhydrous steam, and freely criticized Frost’s mode of conducting his experi- ments as liable to error, at the same time giving instances where he had himself been deceived in the results of prac- tice, as compared with the results of experiments. He tried his plan on an engine having a 9-inch cylinder, and 3-feet stroke, which worked very economically, but he found that the pipes subjected to the heat gave way, and in the aggre- gate did not realize what he expected. He then employed a steam jacket, and a vessel for separating the steam from any unevaporated water, and realized in a large engine 25 per cent, by the separation, and 46 per cent, economy where both steam jacket and separation were used. These experiments were made before Mr. Wright, the Government Comptroller and Inspector of Steam Machinery. Although Dr. Haycraft differs with Frost on some of the details of the experiments, he yet fully admits the economy of stame to be very nearly as great as it is estimated by Frost. The ease with which stame could be tested fully in inside cylinder locomotives, and its admitted economy, have led us to give this abstract of Frost’s experiments, and the opinions of those who have criticized them, as a subject capable of further investigation at a nominal cost. A coiled steam-pipe in the smoke-box end, where the temperature of the escaping gases is always high, would soon indicate its value in locomotive engines, where, if successful, a further reduction in the quantity of fuel consumed would be effected. CHAPTER II. Common Steam. By combining heat and water together in a close vessel steam is produced, and as a well-known elastic motive agent it has become quite a household word. To the hardy miner COMMON STEAM. 143 in developing the treasures of the earth, to the skilful manu- facturer in giving form to his fabrics, to the adventurous mariner in traversing the ocean, and to the traveller in rival- ling the eagle’s speed, steam has alike lent its potent aid, and now displays its agents and its triumphs in the Crystal Palace. Thus to the fullest extent has been realized the prediction of Sir Samuel Morland in 1682, that steam might be harnessed to duty like a quiet horse. Even in the field of locomotion, where the muscular energies of that noble animal seemed to defy mechanical competitors, steam has won some of its greatest triumphs, and extended its usefulness. The following properties of steam now claim our attention : I. Its Elastic Force. II. Its Mechanical Force. III. Its Temperature. IV. Its Volume. V. Its Velocity. VI. Its Expansive Force. VII. Its Practical Force. 1 st. Elastic Force of Steam, An elastic body is one which presses equally in every direction, whilst admitting of being compressed into a smaller or expanded into a larger space, with the power of returning to its original space when restored to its original conditions again. Water, it has been seen, is almost in- compressible, and is therefore a non-elastic body. Air, it has been shown, is compressible, and consequently is an elastic body. As water is made the standard of the specific gravities or weights of heavy bodies, so is air made the standard for gaseous elastic bodies, and its laws are usually applied to illustrate the elasticity of steam in contact with water. Be- sides possessing elastic properties similar to air, steam pos- sesses the additional and valuable one of being easily con- densed by cold to water again. In applying the acknowledged 144 COMMON STEAM. laws of air to steam, they only apply when the steam receives its heat from the water and remains in contact with it, m.ain- taining the given temperature increased or diminished only by the space it occupies. The numerous indicator cards taken from cylinders show that these laws are nearly correct for low- pressure steam; but that for high-pressure steam the curve of expansion is fuller than the theoretical or hyberbolic curve, indicating a greater continuation of force from a less rapid abstraction of heat than is assigned by these laws. Where locomotive engines have inside cylinders fixed in the hot-smoke box, this fuller curve is probably due to the high temperature imparting a slightly starae character to the isolated steam, but influenced by the velocity of the piston and heat on the smoke box. For all ordinary pressures and temperatures of steam in contact with water, the following laws of elastic fluids will practically explain the expansive property of steam. We find, however, that these laws and the practical application of steam to railway locomotion must be deferred to the Second Part, where they will be illustrated and fully explained in a popular manner. 3^uln'mfntaip Scientific 21lcirfe5* MR. W BALE’S SERIES OP RUDIMENTARY WORKS FOR THE USE OF BEGINNERS. NEW LIST EOR 1852 . The whole Series, comprising 105 volumes, will be succeeded by other interesting and useful works more especially intended for Public Instruction, written by learned and efficient masters in the several branches of Education. 1. 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