UC-NRLF 
 
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LI BRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORN: 
 
 OF 
 
 
 Received 
 A ccessions No . // ^ /^//. Shelf No . 
 

UJTIVERSITT 
 
2 w 
 
 H H 
 
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 03 W 
 
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THE 
 
 MODEEN PRACTICE 
 
 OP 
 
 BOILEE 
 
 CONTAINING OBSERVATIONS ON THE 
 
 CONSTRUCTION OF STEAM BOILERS; 
 
 AND UPON FUENACES USED FOE 
 
 SMOKE PREVENTION, 
 
 WITH A CHAPTER ON EXPLOSIONS. 
 BY ROBERT ARMSTRONG, C. E., 
 
 CONSULTING ENGINEER. 
 
 REVISE D, WITH THE ADDITION OF NOTES, AND AN 
 INTRODUCTION 
 
 BY JOHN BOURNE, ESQ. 
 
 llonfcon : 
 E. AND F. N. SPON, 16, BUCKLERSBURY. 
 
 1856. 
 [Sight o/ Translation reserved."] 
 
CONTENTS. 
 
 PAGE 
 
 DEDICATION to Robert Stephenson, Esq., M.P.,F.R.S.,&c. vii 
 
 PKEFACE ix 
 
 INTRODUCTION BY JOHN BOURNE, ESQ., C.E 1 
 
 High. Pressure Steam 2 
 
 Smoke-burning 7 
 
 Explosions 8 
 
 D. K. Clark's table from Regnault's experiments 12 
 
 CHAP. I. 
 
 ON BOILERS GENERALLY, and a radical reform in those 
 
 for marine purposes suggested 17 
 
 Hay-stack boiler 18 
 
 Waggon Boiler 19 
 
 Boulton and Watt boiler 21 
 
 Marine boilers 27 
 
 The Galloway conical tube boiler 33 
 
 Kennedy's water meter 38 
 
 Exhibition boiler of 1851 53 
 
 Elephant boiler 69 
 
 Dunn's patent retort boiler (Fig. 1) 77 
 
 Galloway's patent marine boiler (Fig. 2) 80 
 
 CHAP. II. 
 
 SMOKE PREVENTION and its fallacies 81 
 
 'Losh's double furnace system 87 
 
 Ditto as applied by R. Armstrong 87 
 
 Ditto by J. Bourne 90 
 
 Smoke-burning by John Wakefield 93 
 
 Ditto by J. Parkes 95 
 
 Universal Argand fire-grate 96 
 
 Copy of report on Williams's patent furnace 10*2 
 
VI CONTENTS. 
 
 PAGE 
 
 ACCOUNT OP EXPERIMENTS at Houldsworth's FACTORY 
 IN MANCHESTER, on the economy of smoke preven- 
 tion Ill 
 
 SUMMARY OP RESULTS of experimental trial of the com- 
 parative economy of Mr. C. W. Williams' s patent 
 system of smoke prevention, and the ordinary plan 1 14 
 
 A theory of the BEST POSSIBLE COMBUSTION 116 
 
 CHAP. III. 
 
 EXPLOSIONS : an investigation into some of the causes 
 producing them, and the deterioration of boilers 
 
 generally 121 
 
 Experimental explosion (Fig. 3, p. 124) 123 
 
 The Cross Lane, Manchester, explosion 126 
 
 The Jersey Street ditto ditto 127 
 
 Sticking of safety valves 128 
 
 Deficiency of water 131 
 
 Loss of water by blowing off and leakage (fig. 4, p. 134) 133 
 
 Contrary conclusions drawn 138 
 
 Practical application of preceding principles 143 
 
 Defects of riveted plates 146 
 
 Fig. 5, p. 149, Fig. 6, p. 150. 
 
 How change of form by expansion produces fracture . . 156 
 
 Fig. 7, p. 156, Fig. 8, p. 158. 
 NOTES to Chap. III. 
 
 A. Explosion at Brookes's Flax mill, Bolton 162 
 
 B. Spheroidal condition of water 168 
 
 APPENDIX : No. 1. Review of C. W. Williams's book, 
 
 by J. Bourne, Esq 175 
 
 No. 2. American experiments on explosions 187 
 
TO 
 
 EOBEET STEPHENSON, ESQ., C.E., 
 
 PRESIDENT OF THE INSTITUTION OF CIVIL ENGINEERS, 
 H.P., F.R.S., &C. &C. 
 
 EESPECTED SIR, 
 
 I venture to dedicate these pages to you, both as a 
 manifestation of my reverence for the memory of your 
 late Father, of whose genius and persistency I was 
 for many years an admiring spectator ; and as a slender 
 token of my sense of your own eminent talents as an 
 engineer, and of your estimable personal character. 
 While some engineering reputations are known to 
 rest on diplomatic adroitness, and others are alto- 
 gether hollow and conventional, it is known to be 
 your great distinction that the fabric of your fame is 
 as solid as it is imposing, and is held in most esteem 
 by those whose pursuits best enable them to judge of 
 
 its quality. 
 
 I am, dear Sir, faithfully yours, 
 
 E. AEMSTEONG. 
 
PREFACE. 
 
 THE design of the present work is to place the 
 reader in possession of sound information re- 
 specting some of the best kind of boilers at pre- 
 sent in use, and also to indicate the course which 
 future improvements to be efficient and of 
 material benefit must necessarily pursue. 
 
 The subject of smoke-burning which is 
 reckoned one of the important topics of the 
 present day I have endeavoured to illus- 
 trate in such a manner as both to correct the 
 erroneous and exaggerated statements made 
 by interested patentees, and to convey just 
 and moderate ideas upon that subject. 
 
 The explosions of boilers is a question still 
 involved in much obscurity, some of which 
 
X PREFACE. 
 
 will I hope be dissipated by the remarks I 
 have offered, and as the general introduction 
 of steam of a higher pressure seems to be ine- 
 vitable, this is a subject which more than 
 heretofore stands in need of elucidation. 
 
 I have much gratification in being able to 
 present the present work enriched by the 
 additions and corrections of MR. BOURNE, 
 which he has kindly furnished in conformity 
 with the friendly feeling which he has con- 
 stantly manifested towards me for many 
 years. 
 
 R. AEMSTEONG. 
 
 65, Fenckurch Street, London, 
 1856. 
 
0* 
 
 INTRODUCTION. 
 
 BY JOHN BOURNE, ESQ. 
 
 9. BILLITER STREET, FENCHURCH STREET, LONDON. 
 
 MR. ARMSTRONG lias requested me to revise and add 
 some notes to his present work on steam boilers ; a 
 task which my esteem for him has induced me wil- 
 lingly to undertake, though I do not know that any 
 remarks of mine upon this subject can add weight to 
 the doctrines of so established an authority. It is 
 well known to engineers that Mr. Armstrong has had 
 a more extended experience, and possesses probably a 
 more accurate practical acquaintance with boilers and 
 furnaces than any other person now living, and the 
 public has reason to feel grateful that an engineer of 
 such eminent capacity upon these subjects vouchsafes to 
 offer them the fruits of his long and extensive practice. 
 Of all kinds of books there are none so exhausting as 
 books upon practical engineering. Truths of the 
 most eminent value, and results which it may have 
 B 
 
2 CONVERTIBILITY OF HEAT AND POWER. 
 
 required painful labour to collect are despatched in 
 the compass of a few brief sentences, without any 
 manifestation, at least to the cursory reader, of the toil 
 and reflection involved in the brief exposition. Such 
 works are in fact the essence of thought. There are 
 consequently few of them written, and it ought to be 
 appreciated as a service to humanity when such men as 
 Mr. Armstrong come forward to lay before the public 
 results which it has taken a life of labour to attain. 
 
 The three topics of which Mr. Armstrong has 
 mainly treated in the present work are, first, The Ne- 
 cessity of Strong Boilers; second, Smoke-Burning; 
 and third, Explosions. Upon each of these topics I 
 propose to offer a few remarks, partly in recapitulation 
 of what Mr. Armstrong has said, and partly as exhibit- 
 ing the results of my own experience, or the nature 
 of my own opinions on those subjects. 
 
 HIGH PRESSURE STEAM. 
 
 Eecent investigations have led to the discovery that 
 heat and power are mutually convertible, and we are 
 able to tell what rise of temperature the expenditure 
 of a given amount of mechanical power would impart 
 to water, and reciprocally what quantity of power a 
 
NECESSITY OF STRONGER BOILERS. 3 
 
 given quantity of heat if used in a perfect engine 
 would produce. One result of this discovery is the 
 manifestation of the great loss of power in the best 
 existing steam engines. The best class of Cornish 
 engines do not utilize above one tenth part of the 
 heat expended in working them, so that in the best 
 engines about nine tenths of the power is lost. The 
 theoretical condition under which we would obtain 
 the full effect of the heat in a steam engine consists 
 in heating the water to the temperature of the fur- 
 nace, and in suffering this superheated water to ex- 
 pand under such circumstances, that during its 
 expansion it would produce power. In ordinary 
 engines, however, tins condition cannot be observed, 
 but it will be approached by using steam of a high 
 pressure and of an elevated temperature. The eco- 
 nomy of fuel has now become an object of paramount 
 importance in engines of every class, but more espe- 
 cially so in the case of steam navigation ; as there, 
 not merely the expense of the fuel but the expense of 
 carrying it must be incurred. To attain even a mo- 
 derate measure of economy, steam of a high pressure 
 and elevated temperature is indispensable, and if we 
 have steam of a high pressure we must have a class of 
 boilers introduced into steam vessels which will be 
 
4 NECESSITY OF STRONGER BOILERS. 
 
 able to bear it. Mr. Armstrong lias addressed some 
 of his remarks to this important question, and his 
 opinion seems to be that a modification of that species 
 of boiler termed sometimes the French boiler, and 
 sometimes the Elephant boiler is the most suitable for 
 the altered circumstances of steam navigation. It is 
 clear that a boiler, to be able to bear a high pressure 
 with safety, and without being encumbered with need- 
 less stays, should be a boiler with a cylindrical shell, 
 not too large in diameter. The furnace of such a boiler 
 may either be within it or beneath it. I cannot say 
 that I think internal furnaces very safe with high 
 pressures. If they get even slightly out of shape 
 they are liable to collapse ; and whereas, in the case 
 of a cylindrical shell, the tendency of the internal 
 pressure is to restore the cylindrical form should it 
 nave been accidentally disturbed, in the case of a 
 cylindrical flue or furnace-tube where the pressure is 
 external, the tendency of the pressure is to destroy 
 the cylindrical form, should it have been disturbed 
 accidentally, by overheating or otherwise. My opi- 
 nion, therefore, is, that a fire beneath the boiler is, so 
 far as regards safety, better than a fire within it, sup- 
 posing that the water is clean and that there is no 
 deposit. In marine boilers, however, there is a sedi- 
 
ECONOMY OF HIGH TEMPERATURE IN CYLINDER. 5 
 
 ment lite mortar, which, if allowed to subside to the 
 bottom of the boiler, and a fire be, at the same time, 
 applied to the bottom, will cause the iron to be 
 burned. But by providing collecting vessels within 
 the boiler the deposit will take place within them, 
 and may be from thence blown out into the sea ; and 
 if the operation of blowing off the boilers be suffi- 
 ciently practised, there will, in point of fact, be no 
 sediment at all. By the application, therefore, of 
 such simple expedients as a collecting vessel and a 
 continuous blow-off, boilers may be employed for 
 marine purposes which will not accumulate scale; 
 and, if the formation of scale be prevented, a species 
 of boiler may be used which will enable high pressure 
 steam to be employed with safety. Steam of this 
 kind, used expansively in the engine, will maintain 
 any required speed of the vessel with a much smaller 
 consumption of coal than would otherwise be 
 required. 
 
 In all engines working expansively it is important 
 to maintain the temperature of the cylinder as high 
 as possible, since the temperature of the steam is 
 diminished, and a portion of it is even condensed 
 within the cylinder in consequence of the communi- 
 cation of mechanical power to the piston. For, as a 
 
6 CAUSES OF CONDENSATION IN CYLINDER. 
 
 certain weight of steam has a certain mechanical equi- 
 valent which would be realized if the steam could be 
 used in an engine without waste, it follows that the 
 steam, in so far as it exerts power, must lose heat, 
 else it would have both the power and the heat, 
 which is impossible. Accordingly, it is found that 
 there is a larger condensation in the cylinder of an 
 engine which is at work than would lake place if the 
 engine were not at work, although the steam is 
 admitted to the cylinder freely in both cases. When 
 the engine is stationary the whole condensation is 
 that caused by the radiation of heat : when the 
 engine is at work we have, besides this cause, the 
 communication of mechanical power to the piston, 
 which can only be effected at the expense of some of 
 the heat, and therefore, with a certain condensation 
 of the steam within the cylinder. In a perfect engine 
 there would be no heat discoverable in the condenser, 
 as the whole would have been changed into mechani- 
 cal power ; and, in all engines, there will be an infe- 
 rior quantity of heat in the condenser to that which 
 leaves the boiler, by the equivalent in heat of the 
 mechanical power generated in the engine. Steam- 
 jackets act in counteracting the condensation caused 
 bj the communication of power. 
 
NEW " SMOKE-BURNING FURNACE. 7 
 
 SMOKE-BURNING. 
 
 With respect to smoke-burning, the best species 
 of furnace for the accomplishment of this object, with- 
 out the introduction of countervailing evils, is one 
 which Mr. Armstrong has designed for Woolwich 
 Dock Yard, on a nearly similar plan to several erected 
 by him in the Arsenal. In this furnace the foremost 
 length of bars slopes somewhat towards the mouth ; 
 whereas, the after lengths of bars slope in the contrary 
 direction, or towards the bridge. At the ridge where 
 the opposite slopes meet, there is a doable bearing 
 bar which permits some air to enter the furnace in 
 that situation. The coal in the foremost length of 
 bars is maintained in rapid combustion, whereas the 
 coal upon the after tier of bars is undergoing a slow 
 distillation. In charging the furnace, the coal is 
 thrown chiefly to the back end, so that the surface of 
 the fuel slopes forward from the bridge towards the 
 furnace mouth. This coal,, being lighted on the top, 
 becomes a kind of coal torch. The gas generated by 
 the heat, in passing through the ignited stratum on 
 the surface, is consumed ; and, from time to time, the 
 ignited embers, from which the gas has been expelled, 
 are raked forward, and fresh coal is thrown in to 
 maintain the combustion. Yery little smoke is 
 
8 ADVANTAGES OF FIRE-FEEDING MECHANISM. 
 
 evolved from this species of furnace; and it differs 
 little from a common furnace, either in construction 
 or efficiency."* 
 
 The best species of furnace, however, for marine 
 purposes, is one which, while fulfilling all other indi- 
 cations, will feed the fire by self-acting mechanism. 
 The firing may be accomplished by some of these 
 expedients, not merely in a more efficient manner, but 
 at a materially diminished expense. In the case of 
 a boiler on land, in which a man to look after the 
 engine and boiler is required in any case, the intro- 
 duction of a firing machine to do a portion of his 
 work is not an object of much importance. But in 
 the case of the furnaces of a steam vessel, which 
 require a number of men to attend upon them every 
 watch, an important economy would be accomplished 
 by the substitution of mechanism of an efficient 
 character. 
 | 
 
 EXPLOSIONS. 
 
 The subject of boiler explosions is still involved 
 
 * A representation of this newly designed furnace, as 
 applicable to an " Elephant" Boiler, suitable for dockyards, 
 saw mills, &c., where waste timber and other varieties of 
 mixed fuel are used, is given in the frontispiece. 
 
CAUSES OF EXPLOSIONS. 9 
 
 in a good deal of obscurity. No doubt, a frequent, 
 and, probably, the most frequent, cause of explosion, 
 is the sudden generation of steam produced when 
 the water-level has been allowed to fall so low that 
 the flues get very hot ; and then is suddenly raised, 
 so that the water comes into sudden contact with the 
 heated metal. But there are other cases, in which 
 the water is repelled from the iron by a strong heat, 
 though no undue subsidence of the water-level has 
 been suffered to take place. There are boilers in 
 which the natural order of things is reversed Avhen 
 heat is applied, the water being mostly in the top 
 part of the boiler, and the steam in the bottom. 
 Such boilers necessarily prime very much; or, in 
 other words, much water passes into the steam-pipe, 
 and, at the same time, the part of the boiler on 
 which the flame acts is liable to become overheated 
 from the absence of water in contact with the metal 
 to conduct away the heat. There are boilers in 
 which a lead rivet in the flues may, at any time, be 
 melted out by firing very strongly; the water being 
 so far repelled by the heat as to enable the tempera- 
 ture of the metal to rise to the melting point of lead. 
 In all boilers in which there is ebullition going 
 on, the apparent level of the water will be greater 
 
10 DANGEROUS AMATEUR SMOKE PROJECTS. 
 
 than tlie true level, as the admixture of steam swells 
 the water, producing what is called " false water/' by 
 the drivers of locomotives. One effect of this ficti- 
 tious augmentation of bulk is, that when additional 
 feed water is turned on, from the water level becom- 
 ing too low, the first effect is still further to lower the 
 water level. This anomaly is caused by the conden- 
 sation of the steam mixed with the water of the 
 boiler, when an additional quantity of cold or cool 
 water is introduced; but the water level may, at 
 such times, be again raised by easing the safety-valve, 
 which will enable the steam mixed with the water to 
 swell to larger dimensions when the pressure is 
 reduced, and thus compensate for the partial conden- 
 sation which the introduction of additional feed water 
 has caused. 
 
 One cause of boiler explosions Mr. Armstrong 
 considers to be the unskilful application of smoke- 
 burning projects, which, by producing violent alter- 
 nations of temperature in the boiler bottom, loosen 
 the riveted joints, and, finally, cause them to give 
 way. The occurrence of an accident of this kind 
 in a boiler fitted with the smoke-burning furnace 
 of Mr. Charles Wye Williams has led to a wordy 
 war, which has been waged by that lively gentleman 
 
MR. CLARK'S RESULTS WITH LOCOMOTIVE BOILERS. 11 
 
 for many years. Mr. "Williams is a species of ama- 
 teur engineer ; who, on the strength of an acquaint- 
 ance with the atomic theory, and other elementary 
 chemical truths, acquired, apparently, late in life, has 
 set up as the engineering reformer of the age, in the 
 department of smoke-burning; and he has obtained 
 the approbation of the " Mechanic's Magazine" and 
 other oracles of corresponding authority. A man's 
 ambition need not be very exalted, which is satisfied 
 with such successes; but if there be gratification 
 sufficient to compensate the ridicule arising from 
 harping eternally upon a single trumpery topic, there 
 is no reason, that I know of, why it should not be 
 possessed. 
 
 The subject of locomotive boilers has been treated 
 more fully by Mr. D. K. Clark, in his excellent work 
 on ' ' Eailway machinery/' than by any other author, 
 and he has shown that it is inadvisable to make the 
 area of fire-grate or the area of the chimney very 
 large, that the smoke box should not be of greater 
 capacity than is absolutely necessary to collect the hot 
 air from the tubes, and that the blast-pipe should 
 stop short, by a few inches, of the foot of the 
 chimney, instead of penetrating into it. The follow- 
 ing table is taken from Mr. Clark's work : 
 
TABLE OF THE PROPERTIES OF SATURATED STEAM ; 
 FROM REGNAULT'S EXPERIMENTS. 
 
 Total 
 pressure per 
 
 Relative 
 volume. 
 
 Temper- 
 ature. 
 
 Total Heat. 
 
 Weight 
 of one 
 
 inch. 
 
 
 
 
 cubic foot. 
 
 Ihs. 
 
 
 Fahr. 
 
 Fahr. 
 
 Ibs. 
 
 15 
 
 1669 
 
 213 1 
 
 1178-9 
 
 0373 
 
 16 
 
 1572 
 
 216-3 
 
 11799 
 
 0397 
 
 17 
 
 1487 
 
 219-5 
 
 11809 
 
 0419 
 
 18 
 
 1410 
 
 222-5 
 
 1181 8 
 
 0442 
 
 19 
 
 1342 
 
 225-4 
 
 11827 
 
 0465 
 
 20 
 
 1280 
 
 228-0 
 
 1183-5 
 
 0487 
 
 21 
 
 1224 
 
 2306 
 
 11843 
 
 0510 
 
 22 
 
 1172 
 
 233-1 
 
 1185-0 
 
 0532 
 
 23 
 
 1125 
 
 235-5 
 
 1185-7 
 
 0554 
 
 24 
 
 1082 
 
 237-9 
 
 11865 
 
 0576 
 
 25 
 
 1042 
 
 2402 
 
 1187-2 
 
 0598 
 
 26 
 
 1005 
 
 242 3 
 
 1187-9 
 
 0620 
 
 27 
 
 971 
 
 244-4 
 
 1188-5 
 
 0642 
 
 28 
 
 939 
 
 246-4 
 
 1189-1 
 
 0664 
 
 29 
 
 909 
 
 248-4 
 
 1189-7 
 
 0686 
 
 30 
 
 881 
 
 250-4 
 
 1190-3 
 
 0707 
 
 31 
 
 855 
 
 252-2 
 
 1190-8 
 
 0729 
 
 32 
 
 830 
 
 254-1 
 
 1191-4 
 
 0751 
 
 33 
 
 807 
 
 255-9 
 
 1192-0 
 
 0772 
 
 34 
 
 785 
 
 257-6 
 
 1192-5 
 
 0794 
 
 35 
 
 765 
 
 259-3 
 
 1193-0 
 
 0815 
 
 36 
 
 745 
 
 260-9 
 
 1193-5 
 
 0837 
 
 37 
 
 727 
 
 262-6 
 
 1194-0 
 
 0858 
 
 38 
 
 709 
 
 264-2 
 
 1194-5 
 
 0879 
 
 39 
 
 693 
 
 265-8 
 
 U95-0 
 
 0900 
 
 40 
 
 677 
 
 267-3 
 
 1195-4 
 
 0921 
 
 41 
 
 661 
 
 268-7 
 
 11959 
 
 0942 
 
 42 
 
 647 
 
 270-2 
 
 1196-3 
 
 0963 
 
 43 
 
 634 
 
 271-6 
 
 1196-8 
 
 0983 
 
 44 
 
 621 
 
 273-0 
 
 1197-2 
 
 1004 
 
 45 
 
 608 
 
 274-4 
 
 1197-6 
 
 1025 
 
EEGNAULT^S TABLE OF PROPERTIES OF STEAM. 13 
 
 (Continued.) 
 
 Total 
 pressure 
 per square 
 inch 
 
 Relative 
 volume. 
 
 Temper- 
 ature. 
 
 Total Heat. 
 
 Weight 
 of one 
 cubic foot. 
 
 Ibs. 
 
 
 Fahr. 
 
 Fahr. 
 
 Ibs 
 
 46 
 
 595 
 
 2758 
 
 1198-0 
 
 1046 
 
 47 
 
 584 
 
 277-1 
 
 1198-4 
 
 1067 
 
 48 
 
 573 
 
 278-4 
 
 1198-8 
 
 1087 
 
 49 
 
 562 
 
 2797 
 
 1199-2 
 
 1108 
 
 50 
 
 552 
 
 281-0 
 
 1199-6 
 
 1129 
 
 51 
 
 542 
 
 2823 1200-0 
 
 1150 
 
 52 
 
 532 
 
 283-5 
 
 1200-4 
 
 1171 
 
 53 
 
 523 
 
 284-7 
 
 1200-8 
 
 1192 
 
 54 
 
 514 
 
 2859 
 
 1201-1 
 
 1212 
 
 55 
 
 506 
 
 287-1 
 
 1201-5 
 
 1232 
 
 56 
 
 498 
 
 288-2 
 
 1201-8 
 
 1252 
 
 57 
 
 490 
 
 2893 
 
 1202-2 
 
 1272 
 
 58 
 
 482 
 
 290-4 
 
 1202-5 
 
 1292 
 
 59 
 
 474 
 
 291-6 
 
 1202-9 
 
 1314 
 
 60 
 
 467 
 
 292-7 
 
 1203-2 
 
 1335 
 
 61 
 
 460 
 
 293-8 
 
 1203-6 
 
 1356 
 
 62 
 
 453 
 
 294-8 
 
 1203-9 
 
 1376 
 
 63 
 
 447 
 
 295-9 
 
 1204-2 
 
 1396 
 
 64 
 
 440 
 
 296-9 
 
 1204-5 
 
 1416 
 
 65 
 
 434 
 
 298-0 
 
 1204-8 
 
 1436 
 
 66 
 
 428 
 
 2990 
 
 1205-1 
 
 1456 
 
 67 
 
 422 
 
 300-0 
 
 1205-4 
 
 1477 
 
 68 
 
 417 
 
 300-9 
 
 1205-7 
 
 1497 
 
 69 
 
 411 
 
 301-9 
 
 1206-0 
 
 1516 
 
 70 
 
 406 
 
 302-9 
 
 1206-3 
 
 1535 
 
 71 
 
 401 
 
 303-9 
 
 1206-6 
 
 1555 
 
 72 
 
 396 
 
 304 8 
 
 12069 
 
 1574 
 
 73 
 
 391 
 
 305-7 
 
 1207-2 
 
 1695 
 
 74 
 
 386 
 
 3066 
 
 1207-5 
 
 1616 
 
 75 
 
 381 
 
 307-5 
 
 1207-8 
 
 1636 
 
 76 
 
 377 
 
 308-4 
 
 1208-0 
 
 1656 
 
 77 
 
 372 
 
 309-3 
 
 1208-3 
 
 1675 
 
 78 
 
 368 
 
 310-2 
 
 1208-6 
 
 1696 
 
 79 
 
 364 
 
 311-1 
 
 1208-9 
 
 1716 
 
 80 
 
 359 
 
 312-0 
 
 1209-1 
 
 1736 
 
TABLE OF THE PROPERTIES OF SATURATED STEAM j 
 FROM REGNAULT'S EXPERIMENTS. 
 
 (Continued.) 
 
 Total 
 pressure 
 per square 
 
 Relative 
 volume, 
 
 Temper- 
 ature. 
 
 Total Heat. 
 
 Weight 
 of one 
 cubic foot. 
 
 inch. 
 
 
 
 
 
 Ibs. 
 
 
 Fahr. 
 
 Fahr. 
 
 Ita. 
 
 81 
 
 355 
 
 312-8 
 
 1209-4 
 
 1756 
 
 82 
 
 351 
 
 313-6 
 
 1209-7 
 
 1776 
 
 83 
 
 348 
 
 314-5 
 
 1209-9 
 
 1795 
 
 84 
 
 344 
 
 315-3 
 
 1210-1 
 
 1814 
 
 85 
 
 340 
 
 316-1 
 
 1210-4 
 
 1833 
 
 86 
 
 337 
 
 316-9 
 
 1210-7 
 
 1852 
 
 87 
 
 333 
 
 317-8 
 
 1210-9 
 
 1871 
 
 88 
 
 330 
 
 318-6 
 
 1211-1 
 
 1891 
 
 89 
 
 326 
 
 319-4 
 
 1211-4 
 
 1910 
 
 90 
 
 323 
 
 320-2 
 
 1211-6 
 
 1929 
 
 91 
 
 320 
 
 321-0 
 
 1211-8 
 
 1950 
 
 92 
 
 317 
 
 321-7 
 
 12120 
 
 1970 
 
 93 
 
 313 
 
 322-5 
 
 12123 
 
 1990 
 
 94 
 
 310 
 
 323-3 
 
 12125 
 
 2010 
 
 95 
 
 307 
 
 324-1 
 
 1212-8 
 
 2030 
 
 96 
 
 305 
 
 324-8 
 
 1213-0 
 
 2050 
 
 97 
 
 302 
 
 325-6 
 
 1213 3 
 
 2070 
 
 98 
 
 299 
 
 326-3 
 
 1213-5 
 
 2089 
 
 99 
 
 296 
 
 327-1 
 
 1213-7 
 
 2108 
 
 100 
 
 293 
 
 327-8 
 
 12139 
 
 2127 
 
 101 
 
 290 
 
 328-5 
 
 1214-2 
 
 2149 
 
 102 
 
 288 
 
 329-1 
 
 1214-4 
 
 2167 
 
 103 
 
 285 
 
 3299 
 
 1214-6 
 
 2184 
 
 104 
 
 283 
 
 3306 
 
 1214-8 
 
 2201 
 
 105 
 
 281 
 
 331-3 
 
 1215-0 
 
 2218 
 
 106 
 
 278 
 
 331-9 
 
 1215-2 
 
 2230 
 
 107 
 
 276 
 
 332-6 
 
 1215-4 
 
 2258 
 
 108 
 
 273 
 
 333-3 
 
 1215-6 
 
 2278 
 
 109 
 
 271 
 
 334-0 
 
 1215-8 
 
 2298 
 
 110 
 
 269 
 
 334-6 
 
 1216-0 
 
 2317 
 
 HI 
 
 267 
 
 335-3 
 
 1216-2 
 
 2334 
 
REGNAULT'S TABLE OF PROPERTIES OF STEAM. 15 
 
 (Continued.) 
 
 Total 
 pressure 
 per square 
 inch. 
 
 Relative 
 volume. 
 
 Temper- 
 ature. 
 
 Total Heat. 
 
 Weight 
 of one 
 cubic foot. 
 
 Ibs. 
 
 
 Fahr. 
 
 Fahr. 
 
 Ibs. 
 
 112 
 
 265 
 
 336-0 
 
 1216-4 
 
 2351 
 
 113 
 
 263 
 
 3367 
 
 1216-6 
 
 2370 
 
 114 
 
 261 
 
 337-4 
 
 1216-8 
 
 2388 
 
 115 
 
 259 
 
 338-0 
 
 12170 
 
 2406 
 
 116 
 
 257 
 
 338-6 
 
 1217-2 
 
 2426 
 
 117 
 
 255 
 
 339-3 
 
 1217-4 
 
 2446 
 
 118 
 
 253 
 
 339-9 
 
 12176 
 
 2465 
 
 119 
 
 251 
 
 340-5 
 
 1217-8 
 
 2484 
 
 120 
 
 249 
 
 341-1 
 
 1218-0 
 
 2503 
 
 121 
 
 247 
 
 341-8 
 
 1218-2 
 
 2524 
 
 122 
 
 245 
 
 342-4 
 
 1218-4 
 
 2545 
 
 123 
 
 243 
 
 343-0 
 
 12186 
 
 2566 
 
 124 
 
 241 
 
 343-6 
 
 1218-7 
 
 2587 
 
 125 
 
 239 
 
 344-2 
 
 12189 i -2608 
 
 126 
 
 233 
 
 344-8 
 
 1219-1 
 
 2626 
 
 127 
 
 236 
 
 345-4 
 
 1219-3 
 
 2644 
 
 128 
 
 234 
 
 346-0 
 
 1219-4 
 
 2662 
 
 129 
 
 232 
 
 346-6 
 
 1219-6 
 
 2680 
 
 130 
 
 231 
 
 347-2 
 
 1219-8 
 
 2698 
 
 132 
 
 228 
 
 348-3 
 
 1220-2 
 
 2735 
 
 134 
 
 225 
 
 349-5 
 
 1220-6 
 
 2771 
 
 136 
 
 222 
 
 350-6 
 
 1220-9 -2807 
 
 138 
 
 219 
 
 351-8 
 
 12212 -2846 
 
 140 
 
 216 
 
 352-9 
 
 1221-5 
 
 2885 
 
 142 
 
 213 
 
 354-0 
 
 1221-9 
 
 2922 
 
 144 
 
 210 
 
 355-0 
 
 1222-2 
 
 2959 
 
 146 
 
 208 
 
 356-1 
 
 1222-5 
 
 2996 
 
 148 
 
 205 
 
 357-2 
 
 1222-9 
 
 3033 
 
 150 
 
 203 
 
 358-3 
 
 12232 
 
 3070 
 
 160 
 
 191 
 
 363-4 
 
 1224-8 
 
 3263 
 
 170 
 
 181 
 
 368-2 
 
 1225-1 
 
 3443 
 
 180 
 
 172 
 
 372-9 
 
 12277 
 
 3623 
 
 190 
 
 164 
 
 377-5 
 
 1229-1 
 
 3800 
 
 200 
 
 157 
 
 381-7 
 
 1230-3 
 
 3970 
 
16 CONCLUSION. 
 
 With these cursory remarks I dismiss Mr. Arm- 
 strong's present work. Its main suggestions, namely, 
 the necessity of the adoption of cylindrical boilers in 
 all cases in which economy of fuel is important, the 
 practicability of burning smoke by simple arrange- 
 ments without, however, the accomplishment of much, 
 if any direct saving of fuel, the advantage of fire feeding 
 mechanisms in steam vessels, and the doctrine of the 
 accidental deficiency of water in boilers being the 
 main cause of explosions, are all, in my judgment, 
 sound doctrines, and, if so, public benefit cannot fail 
 to arise from their wide acceptation. 
 
 J.B. 
 
 KOTE TO REG:N T A TILT'S TABLE, PREVIOUS PAGE. 
 The above table of corresponding pressures, temperatures, 
 and volumes of saturated steam is by the kind permission of 
 Mr. Clark copied from his valuable work. The pressures 
 and temperatures are the direct results of M. Regnault's 
 experiments. The relative volumes are obtained by means 
 of the formula 
 
 P 
 
 The fourth column is the result of direct experiment by 
 llegnault. And the fifth column is calculated by dividing 
 62-321 lb., the weight of a cubic foot of water at 62 by the 
 relative volume. 
 
17 
 
 CHAPTER I. 
 
 ON BOILERS GENERALLY, AND A RADICAL REFORM IN 
 THOSE FOR MARINE PURPOSES SUGGESTED. 
 
 THE main design of this short essay is to impart in 
 few words, that information respecting boilers and 
 furnaces, which persons employing steam-engines, 
 desire to possess, but which they have not much 
 time to acquire. While yielding our approbation to 
 all investigations touching the science of steam, 
 which seem likely to illustrate its nature, we are at 
 the same time conscious that the bulk of mankind 
 immersed in active business, have but little time for 
 such speculations; and it is our design rather to state 
 results, and enunciate general laws, such as are found 
 to govern successful practice, than to embark upon the 
 wide sea of theoretical disquisition, or to announce 
 any mere theoretical conclusions. Still less is it our 
 intention to parade the elementary truths of che- 
 mistry as baits for the admiration of the ignorant 
 expanded into all the forms proper to laborious dul- 
 c 
 
18 THE HAY-STACK BOILER. 
 
 ness and varied in every phrase of emphatic iteration. 
 That task has already been performed by Mr. Charles 
 "Wye Williams in his work on the " Combustion of 
 Coal and the Prevention of Smoke/' and the merits 
 in which that work is deficient have been compen- 
 sated by its artificial notoriety. We should be sorry 
 to deprive Mr. Williams of any portion of the repu- 
 tation which has cost him so much and the quality of 
 which seems to satisfy his ambition, and there is cer- 
 tainly no danger that in the present work we shall 
 run into any similar extravagance, having so painful 
 an example before us of this species of folly. To 
 theory we take no exception, theory being indeed 
 only the connection of individual facts into such a 
 chain as to constitute a natural law. 
 
 HAY-STACK BOILER. 
 
 This boiler is termed the hay-stack boiler from its 
 shape. In some districts it is called the balloon 
 boiler, and the kettle boiler. It is a good kind of 
 boiler up to 10 or 12-horse power, and 10 or 12 Ibs. 
 pressure, where boilers are required to stand singly. 
 It is strong enough within those limits, and has the 
 greatest capacity for the least quantity of material 
 
THE WAGGON BOILER. 19 
 
 employed. Independent of its economy, which, with 
 inferior fuel, need not be less than that of any other 
 kind, it has, perhaps, the greatest evaporating power 
 for its dimensions, and if set up, as it usually is, with 
 a single wheel draft, it requires only a small chimney. 
 The shape of the bottom of this boiler is generally 
 not so well adapted as some other kinds of boilers 
 for applying the usual arrangements for consuming 
 smoke, but if made of copper, as such boilers are in 
 some of the London breweries, they admit of coke 
 being used to very great advantage. 
 
 In Staffordshire, and some other mining districts, 
 the hay-stack boiler has been frequently made much 
 too large ; and where this defect has been sought to 
 be corrected, by carrying the flue spirally twice round 
 the boiler, the result has usually been unsuccessful, 
 if not dangerous. 
 
 THE WAGGON BOILEK. 
 
 This boiler is, in principle, the hay-stack boiler 
 just described, only put into an oblong instead of a 
 circular form on the ground plan. It therefore per- 
 mits of facilities in arranging a number of boilers 
 side by side without wasting space. It is distin- 
 
PROPERTIES OP THE WAGGON BOILER. 
 
 guished in mining districts as the oblong boiler. In 
 other places it is sometimes called the caravan boiler, 
 and by Mr. Wicksteed, the waggon-head boiler. It 
 possesses some advantage over the hay-stack boiler in 
 its being better adapted for the use of rich bituminous 
 or flaming fuel, and Newcastle coal generally. It 
 admits of being made of such a length, that the flame 
 from a well-managed fire will be generally expended 
 before reaching the end; and it can be easily varied 
 in its proportions to suit the many varieties of flaming 
 fuel wood as well as coal. As flaming coal is also 
 smoky coal, the waggon boiler from its rectangular 
 plan, is suitable for the application of such coal, 
 because it admits of the ordinary rectangular fire- 
 grate, with convenient space beyond for any ar- 
 rangement of the furnace chamber and bridges, so as 
 to meet almost any requirement for smoke-consuming 
 purposes. 
 
 The waggon boiler is, except in the direction of 
 its length, nearly as strong as the hay-stack boiler, 
 up to 5 feet diameter, and if provided with one, two, 
 or three longitudinal stays, and 4 such stays of \\ 
 inch square from end to end if above that diameter, 
 together with cross stays at every two feet in the 
 length, it may be safely worked up to 10 Ib. on the 
 
WAGGON BOILERS WITH INTERNAL FLUES. 21 
 
 square inch. For this pressure it is usually made of 
 plates to average inch thick all round, the top being 
 never less than , and the ends ought to be seven- 
 sixteenths of an inch. Up to 20 or 25 horse-power, 
 boilers which are as many feet in length by 5 to 5 \ 
 feet wide, or equivalent proportions, made in this 
 way, will weigh 17 or 18 Ib. per square foot of total 
 surface, inclusive of nvets, overlap of plates, stays, 
 &c. 17 or 18 square feet of such surface, may be 
 reckoned as equivalent to a horse-power; from these 
 data, the weight and cost (at present 25 to 30 shil- 
 lings per cwt.) is soon obtained. 
 
 Within the above limits, no boiler ever made can 
 exceed this one in efficiency, economy, and durability, 
 if well-proportioned to the engine it works, and to 
 the fuel supplied to it. If required of greater power 
 than 20 or 25 horse, boilers of this kind are made 
 deeper in proportion to their length, and an internal 
 flue tube is introduced, and such boilers are then called 
 the 
 
 BOULTON AND WATT BOILER. 
 
 This boiler, when of 30 or 40 horse-power, is more 
 economical in fuel than the plain waggon form ; but 
 is weaker for the same thickness of iron, and ought 
 
22 RULES FOR PROPORTIONING BOILERS. 
 
 not to be worked at more than 8 Ib. per square inch. 
 Its power is calculated in the same way as that of the 
 waggon boiler, excepting only that the breadth or 
 diameter of the internal tube is to be considered as 
 so much added to the width of the boiler itself. 
 Thus, if a waggon boiler of 20 feet long, by 5 feet 
 wide, be equal to 20-horse power, being at the usual 
 rate of 5 square feet of water surface, or horizontal 
 ground plan per horse power, then a Boulton and 
 "Watt Boiler of the same horizontal dimensions exter- 
 nally, but having its inside flue tube of 2 feet dia- 
 meter, will be two-fifths more powerful, or 28 instead 
 of 20-horse power, it must be supplied, of course, with 
 a proportionate increase of fire-grate, and is thus 
 computed : 
 
 Length 20 ft. x (5 + 2 =) 7 ft. wide = 140 = g 
 Divided by 5 feet per H.P. 5 
 
 horse power. 
 
 With these dimensions, however, it would have to 
 be of very considerable depth, in order to have the 
 required capacity for holding a sufficient quantity of 
 water and steam for that power. It is therefore 
 found preferable to make such boilers from 6 to 8 
 feet wide, by 8 or 9 feet deep, and they should never 
 be more than 28 or 30 feet long. If a boiler of this 
 
RULES FOR PROPORTIONING BOILERS. 23 
 
 kind is not required to be above 40 horse power, 
 there is no necessity, unless very bituminous coal is 
 used, for its being much more than 20 feet in length. 
 With that length it may be made 6 ft. 6" wide, by 
 8 ft. or 8 ft. 6" deep, and contain a circular flue-tube 
 of 3 J ft. diameter. The computation in the same 
 manner as above, will then stand as follows: 
 
 20ft.x(6ft. V + 3ft.6" =) 10ft. 200 
 
 = = - = ^U J.r. 
 
 5 5 
 
 As in my former works upon steam boilers, I gave 
 some examples of the arithmetical calculations con- 
 nected with this subject, at full length, for the spe- 
 cial benefit of engine-men and stokers ; and having 
 since ascertained the utility of such numerical exam- 
 ples for the purpose intended, I shall give a similar 
 example here : 
 
 Width or diam. of boiler 6*5 feet. 
 
 Ditto of inside flue-tube 3*5 
 
 10-0 
 Multiply by the length 20 
 
 Divide by 
 
 200 
 
 40-horse power. 
 
24 ETJLES FOE PEOPOETIONING BOILEES. 
 
 The slide rule formula for all such cases is, 
 
 A | Gauge point 5 | or 5*7 | diam. of boiler and flue 10 
 <5 I Horse power 40 | 35 ["Length of ditto 20 
 
 If the second divisor or gauge point 5*7 be used, 
 which gives about a square yard, or 9 square feet of 
 effective heating surface per H. P v the result is seen 
 to be only 35 H. P. But, by placing 40, the power 
 required, opposite to 5-7 in the place of 35, we shall 
 find, opposite to 10, the proper length to make the 
 boiler 40-horse power at that rate, namely 22*8 feet 
 as below, 
 
 A [ 5-7 | diameter 10 | or 11 j. 
 | 40 | length 22-8 | 20~ 
 
 or, retaining the same length 20 feet as before, oppo- 
 site to it is seen 11 as above, for the diameters of 
 boiler and flue together, which may be conveniently 
 made 8 feet, and 3 feet 6 inches respectively. 
 
 A Boulton and Watt Boiler, thus proportioned, is 
 much more economical of fuel than a waggon boiler 
 of the same size or power ; but it requires more total 
 surface of iron plate, although it is measured pre- 
 cisely in the same way, that is, the lower half of all 
 the flues is left out in the measurement, as non-effective 
 in generating steam, and one half only of the vertical 
 
MODES OF STAYING BOILERS. 25 
 
 heating surface is considered as effective heating sur- 
 face. 
 
 In respect to strength, this boiler is weaker than the 
 unflued waggon form, in proportion as its depth exceeds 
 its diameter; notwithstanding it may be made of thicker 
 plates in proportion to its increased size*. This defect 
 is partially remedied by having two tiers of cross 
 stays 1" square, placed one above, and the other 
 below the inside flue. Besides these cross stays, it is 
 usual to support the bottom of the boiler by oblique 
 stays, commonly called "upright" stays, attached to 
 the arch of the boiler bottom, and the other end 
 secured by cotters upon, and near the ends of the upper 
 cross stays. All these stays of which there are 4 for 
 each plate in the length of the boiler, are attached 
 by broad wrought iron straps and cotters, which last 
 should not be made too taper, for when so, they are 
 liable to wriggle loose by the working of the boiler. 
 Besides the usual number of longitudinal stays from 
 end to end, as in the plain waggon boiler, some per- 
 sons put in " angle stays," extending from near the 
 centre of each end, to the second or third plate on 
 each side. Again, we occasionally find a stay carried 
 obliquely downwards from the flat end of the boiler to 
 the top of the flue tube, which we consider injudicious, 
 
26 STAYING OF BOILERS. 
 
 and rather tending to do harm than good. For the 
 tube itself generally is, or should act as a stay from 
 end to end ; and on that account should not be drawn 
 out of its direct tensile action by any side attachment, 
 liable to create lateral strain. The probable reason 
 why stays were originally placed in this part by 
 Boulton, Watt and Co., is that they did not latterly 
 carry the flue-tube right through from end to end, 
 but terminated it in a flat topped "take up" inside 
 the boiler, to support the top plate of which this 
 oblique stay assisted. With respect to similar oblique 
 or angular stays carried from the ends to the arched 
 top of the boiler, we cannot say much in their favour, 
 although some of them have become popular under 
 the name of "gusset" stays, from their being made of 
 triangular plates instead of square bars, which would, 
 we think, be more suitable, if needed at all. How- 
 ever appropriate these gusset stays, or stay plates, 
 instead of stay bars, may be in plate iron bridges and 
 structures of that kind, where stiffness from external 
 pressure and from twisting is the main object in view, 
 any peculiar value they can have in resisting the 
 internal strains to which steam boilers are subject, is 
 not very apparent, especially when we consider that 
 every unnecessary rivet, not to say seam of rivets, in 
 a boiler is a source of weakness, not strength. 
 
WELDING OF BOILER PLATES. 27 
 
 If larger boiler plates could be manufactured, or 
 could large plates be as easily ascertained to be sound 
 as small ones, then the less rivetting the better. 
 Since the new system of welding, instead of rivetting 
 the edges of boiler plates together has been so far 
 perfected by the patent process of Mr. Bertram, late 
 of Woolwich Dockyard, as to prove its superior 
 strength to even double rivetting, it is not now too 
 much to look forward to the time when not only 
 a boiler, but the iron hull of "the noblest machine 
 that ever was invented " a SHIP, instead of being, as 
 it may now be termed, "stitched" together in patches 
 by " seams " and " gussets," will be forged in one 
 entire piece ; at all events, Mr. Bertram has demon- 
 strated the practicability of welding together iron 
 plates in a cheap, rapid, and efficient manner, and 
 there can be no doubt that his discovery must in time 
 find many valuable applications. 
 
 MARINE BOILERS. 
 
 In this country marine boilers are almost all low 
 pressure boilers, but the pressure has been gradually 
 creeping up for several years, and pressures of from 
 20 to 301bs. on the square inch, are now by no 
 means unusual. At the same time no corresponding 
 
28 DEFECTS IN THE PRESENT 
 
 improvements have been made in the structure of the 
 boilers to ensure an equal measure of safety to that 
 which previously existed. No doubt modern marine 
 boilers are made of good iron, are well rivetted and 
 are very much stayed. But the stays, especially in 
 the region of the steam chest, are speedily corroded 
 by the action of the steam ; the plates of the boiler 
 also get thin, so that unless the engineer reduces the 
 weights on the safety valve as the boiler gets worn, 
 explosion will be apt to occur from mere weakness of 
 the boiler. 
 
 For tug boats and other commercial purposes, for 
 war, and for sea-going vessels generally, we do not 
 see how very high pressure, whether with condensing 
 or non-condensing engines, and for war ships, extreme 
 high pressure is to be avoided. The economy of the 
 combined high and low pressure engine, and the ad- 
 vantages of working very expansively, in various ways 
 are so great, and so much more important afloat where 
 the fuel has to be carried, than ashore, that it has 
 long been a problem, whether it would not eventually 
 be true economy to adopt the very strongest boilers 
 which can possibly be made at once. Say to be able 
 to work at not less than 100, and up to 200 Ib. on 
 the square inch ; and we really see no very great 
 
CONSTRUCTION OF MARINE BOILERS. 29 
 
 difficulty in making boilers quite as safe from explo- 
 sion at 200 Ib. as the ordinary marine boilers as now 
 made, are at 20 Ib. pressure. It is merely a question 
 of investment of capital, not in large ships, but in 
 strong ships, so that we are inclined to side with those 
 who would adopt such a system as good commercial 
 policy. Because if the boilers are capable of working 
 safely at 200 Ibs. there is no reason why, with proper 
 arrangements, such boilers with suitable engines, 
 should be less economical than ordinary boilers if 
 worked at ordinary pressures. The greater cost of 
 the boiler in the first instance will not only confer 
 greater strength but greater durability. 
 
 The present construction of the multitubular 
 boiler, as it is called, may be truly stated as a disgrace 
 to the science of this age of progress. The marine 
 boiler yet remains, in fact, no more than a locomotive 
 boiler, with the most important part of that boiler, 
 the fire-box left out. It is not that we would put a 
 fire-box, or anything like it, aboard a steam ship, 
 though well adapted to the rail ; that is only suited 
 for burning coke which is too bulky a fuel for marine 
 purposes. Besides a blast or strong draft by some 
 means seems a necessity for burning coke with ad- 
 vantage. 
 
30 SUGGESTIONS OF IMPROVEMENT 
 
 Very much more, however, is either the blast or 
 jet required, by reason of the multitude of small tubes 
 through which the products of the combustion must 
 be drawn. This creates an additional difficulty with 
 the present marine boiler, and it is not likely that 
 from 20 or 30 per cent, of its power can be afforded for 
 blowing the fire, as is the case with some locomotives. 
 
 What then, it may be asked, is the first step to 
 improve the present practice? And my answer is 
 ready, If a moderate improvement only is permitted, 
 without greatly disturbing present arrangements of 
 space in the ship, and a due regard to venerated pre- 
 judices, which we have seen created during a single 
 generation, and which have in that time erected the 
 crude suggestion of Booth, successful though it has 
 been made by others, almost into the position of an 
 institution, the obvious course is to improve the fur- 
 naces, shorten and widen the tubes, and, when draft is 
 deficient, apply the exhausting fan with a short funnel. 
 Although we do not insist so strongly on the last 
 item, it may be observed in passing, that it would 
 make " smoke burning" with economy in steam ships 
 possible ; at present it is not. (See Chap, ii.) 
 
 Should a radical reform of the marine boiler be 
 aimed at, and we have never ceased strenuously to 
 
IN MARINE BOILERS. 31 
 
 urge its necessity, whoever attempts it must not 
 stick at trifles. The Jboilers, in the first place, ought 
 not to be " crushed down" to the bottom of the ship, 
 where the draft has such difficulty to descend down 
 after them. We would, in fact, abolish the stoke- 
 hole, if not do away with the stokers, and stoking 
 also. Instead of placing the fires so low down that, 
 in a leaky ship they are soon drowned out, we would 
 have them close up to the deck, in whatever situation 
 the engines might be fixed. The "firing stage" 
 should really be a platform elevated to the light of 
 day, on which the most important processes in the 
 economy and progress of a steam vessel is carried on, 
 and to which the coals may be elevated, and, if re- 
 quired placed in the furnaces also, by means of very 
 simple self-acting mechanical appliances. In giving 
 a reluctant assent to the proposition, let it not be 
 forgotten by the reader, that this change of position 
 in the boilers would really increase the available room 
 for cargo, inasmuch as none would be wasted in pas- 
 sages up and down for the hands, and for ventilation, 
 to say nothing of the greater safety of the ship from 
 fire; and though last, not least, when we think of the 
 possible fate of the " President " or the " Pacific," 
 from explosion. 
 
32 ADVANTAGES OE A HIGH PRESSURE. 
 
 In the case of vessels of war where the boilers, in 
 this elevated position, might te obnoxious to the 
 effects of shot, &c., the boilers may be retained in the 
 usual position, and in such cases the room occupied 
 by the stoking space is not so objectionable. 
 Wrought iron boilers of simple forms, containing a 
 steam pressure of 200 Ibs. per square inch, will be the 
 most suitable in such cases. 
 
 The communication of the boilers with each other, 
 and with the cylinders may be easily arranged below 
 the water level in the manner of the locomotive. 
 
 The kind of boilers we propose for marine purposes, 
 are not new schemes, but the inventions of practical 
 men, matured by the experience afforded by extensive 
 use. The principle is that of WOOLF where the pres- 
 sure is exerted only within cylinders of comparatively 
 small diameter, say up to 2^ or even 3 feet. The 
 species of boiler made by Hall of Dartford, and others, 
 known in London as the elephant boiler, may be ar- 
 ranged to work at a pressure of 150 to 200 Ibs., and 
 for low-pressure (say 80 to 100 Ibs.) when used in 
 wooden vessels where internal furnaces are insisted 
 on, we would recommend the modification patented 
 by Galloway, of Manchester. The elephant boiler 
 has been much used by the Trench, though but par- 
 
GALLOWAY'S CONICAL TUBE BOILER. 33 
 
 tially, perhaps, for steam navigation. Galloway's 
 boiler has been used in this capacity, I believe, to 
 some extent ; my own immediate experience with both 
 has been principally confined to land. The latter boiler 
 was first introduced into practice in London, and 
 erected for public inspection and trial at the Great 
 Exhibition in 1851. This boiler I shall now describe. 
 
 THE GALLOWAY CONICAL TUBE BOILER. 
 
 I use the term " conical/' rather than " patent/' 
 in the designation of this boiler, because the pa- 
 tentees have other patent boilers, also with vertical 
 tubes, which tubes are not all conical, being partly 
 "fire tubes" or, strictly speaking, small tubular flues, 
 on the principle of the locomotive; and also to 
 distinguish it in its most prominent feature, in 
 relation to strength and durability, from the boilers 
 of the American steamers "Pacific" and "Baltic/' 
 Collins's line. The great and most important point 
 of difference between the American and English 
 boiler is, that in the former, the large internal fire- 
 flue, or flame-chamber is occupied by a great number 
 of parallel tubes, about 2 inches diameter, and 5 feet 
 long, placed vertically, and connecting the upper and 
 lower portions of the water chamber. Through these 
 
34 GALLOWAY'S CONICAL TUBE BOILER. 
 
 tubes the water, of course, circulates very rapidly, 
 and there can be no doubt this arrangement forms a 
 most effectual means of wanning a large quantity of 
 water in a short time, and with great economy. 
 Whereas in the Galloway boiler, the space behind the 
 furnace is occupied by a smaller number of taper, 
 or conical tubes of 5 or 6 inches in diameter at the 
 lower, and nearly double that diameter at their upper 
 ends ; consequently requiring more space in length of 
 boiler, though less in depth, than the American 
 plan, for the same quantity of heating surface. 
 
 In a pamphlet written by Captain llamsay, R.IsT., 
 published in 1851, entitled, " Eemarks on some 
 of the causes that retard the progress of our 
 STEAM NAVY/' several good observations are made 
 in illustration of the necessity of using much higher 
 steam than previously, in ships of war, and the diffi- 
 culty in attaining that object with the ordinary 
 construction of marine boiler, as well as on the ill- 
 adaptation of that boiler with small tubes to the 
 proper combustion of bituminous coal or other 
 flaming fuel. In discussing this subject, Page 58, 
 Captain Eamsay remarks, 
 
 "The strongest form of boiler which we are ac- 
 quainted with is one invented by Messrs. J. and W. 
 
GALLOWAY'S CONICAL TUBE BOILER. 35 
 
 Galloway of Manchester, and which, we believe, 
 might, with modifications, be adapted to marine pur- 
 poses. The peculiar principle of this boiler is the 
 series of short vertical tubes which act as stays. The 
 only objection to which these boilers are liable, as 
 marine boilers, would be, that using water tubes, 
 there is a liability to prime ; but we would meet that 
 objection by making the upper part of the tubes very 
 large in proportion to the lower parts." 
 
 Now this last suggestion is a very important one, 
 and had been previously made by the present writer, 
 not with a view to prevent priming, solely, but also 
 for insuring a more effective action of the flame 
 against the sides of the tubes, as well as to prevent 
 their being injured by overheating and burning out 
 at their upper ends. In fact, I professionally 
 advised the inventors, on being consulted by them, 
 previously to taking out their patent for this water- 
 tube boiler, in 1850, to adopt that course. This 
 advice they followed, and have continued to pursue, 
 with very great success ever since. Messrs. Galloway 
 having supplied several 50 horse boilers, fortheGutta 
 Percha Company's Works, City Road, and to several 
 other factories in London, during that and the 
 following year. 
 
30 EVAPORATIVE POWER OF BOILERS. 
 
 One of those boilers, erected under my superin- 
 tendence, at the City Eoad Works is described and 
 figured in my " Eudimentary Treatise on Steam 
 Boilers/'' In that wort it was stated that this boiler 
 was capable of evaporating a cubic foot of water per 
 minute, with only about 6 Ibs. of bituminous coal 
 per hour, not of the best quality, while driving a 
 30-horse non-condensing engine indicating 50-H.R, 
 besides supplying steam for other purposes. This 
 great, if not unprecedented, degree of economy has 
 been doubted by some persons who have in vain 
 tried to evaporate a cubic foot of water by less than 
 8 or 9 Ibs. under the same circumstances : that is, 
 while driving an engine at full work, which is a very 
 different thing to the kind of evaporating experi- 
 ments some time ago carried on by order of 
 Government, and published in sundry Eeports to 
 Parliament on coals suited to the steam navy. These 
 Eeports are merely an account of the results of cer- 
 tain laboratory experiments, and, however valuable as 
 scientific facts such investigations may be, it must be 
 said that the labours of the eminent men engaged 
 have been of little use in improving or illustrating 
 the actual practice of engineers. The highest result 
 obtained in these experiments was, 10*21 Ibs. of 
 
MODE OF DETERMINING EVAPORATION. 37 
 
 water evaporated from 212 for each Ib. of the best 
 Welsh coal. (Ebbw Vale.) This result was obtained 
 with a Cornish boiler. With a Galloway boiler, 
 however, when new, with thinner tubes, that is, 
 J inch instead of five-sixteenths, and welded up the 
 side instead of being rivetted, I have, occasionally, 
 obtained a larger performance than that given in the 
 statement referred to. The result of the experiment 
 in question was, that eleven and one-tenth pounds of 
 water was evaporated by each Ib. of coal consumed of 
 an inferior kind called East Adair's main. The pressure 
 of the steam was carefully kept up during the experi- 
 ment, (nearly 2 hours,) at exactly 40 Ibs. per square 
 inch, the engine doing its ordinary work, except that 
 the feed pump was stopped off, and, consequently, no 
 feed-water was going into the boiler, which enabled 
 me to measure very accurately the fall of the water- 
 level in the glass water-gauge; and, knowing the 
 exact internal dimensions of the boiler, the quantity 
 of water boiled away was thus clearly ascertained 
 with sufficient exactness for a short experiment : at 
 any rate, the result was as near the truth as the 
 quantity of coal used could be measured, considering 
 that the quantity of fuel on the bars had to be esti- 
 mated, to be equal at the beginning and the end of 
 
38 WATER-METER TOR STEAM BOILERS. 
 
 the experiment. At that time (1850) no such thing 
 as an absolutely correct water-meter, at a moderate 
 expense, for boilers, was in existence; that deside- 
 ratum, however, now appears to be attained by the 
 invention of Mr. Kennedy of Kilmarnock. So 
 important an appendage to steam boilers as a correct 
 boiler -meter, constantly registering the quantity of 
 water boiled away, has been long looked for and 
 longed for by every honest engineer. Besides being 
 a continual check against that neglect of the feed- 
 water which too frequently results in explosions, it 
 will also be a serviceable check on the extravagant 
 expectations often raised upon the statements of 
 interested patentees of their schemes for saving fuel. 
 I do not risk much in predicting that when these 
 meters become more generally known and used, they 
 will produce a revolution in the engine and boiler 
 trade, quite as great as was produced by the first 
 general introduction and improvement of Watf s 
 indicator, by the late Mr. John M 'Naught of Glas- 
 gow ; an era which makes us now look back to those 
 times of hemp-packed pistons, " never tight," and 
 air-pump buckets " never meant to draw," as to a 
 long-bygone age, though but few years have elapsed 
 since that barbarous time. And now, by the help of 
 
TEST OF SMOKE-BURNING PROJECTS. 39 
 
 the boiler-meter, we hope soon to dispel the present 
 uncertainties of some hundreds of smoke patentees 
 as to whether their plans save seven per cent, of fuel, 
 or seventy, although, for aught they know, they are 
 just as likely to do one as the other ; but I have a 
 strong suspicion that the best of them, and I am 
 far from denying that there are many good ones, 
 will be found to come nearer two per cent, than 
 twenty.* 
 
 * Except, perhaps, 20 per cent, below par, negative 
 " saving." But we trust this subject will yet receive, as it 
 deserves, more serious treatment. At a meeting of smoke 
 patentees, called by the authorities of Leeds, some years 
 ago, one, the most notorious of them, whom we will call 
 No. 1, promised 50 per cent, saving in fuel. No. 2, equally 
 well known, promised 60 ! while others promised 70 and 
 80 ! ! not being particular to a few per cents., whom we may 
 call, collectively, No. 3. The results are, No. 1 sent a 
 new steam ship to sea with his plan, which ship very 
 narrowly escaped the fate of "the President," being, 
 only through the greatest care and discretion of her 
 commander, brought back to Cork, to repair her boilers, 
 after being nine days out on her way to America. No. 2 
 had his plan in operation not far from the Manchester 
 Exchange, which ended in a well-known terrible explosion, 
 killing nine or ten people. While No. 3, an 80 per cent, 
 man, has more recently had one of the most destructive 
 explosions on record in Yorkshire. 
 
40 EXPERIMENTS ON EVAPORATION. 
 
 Eeverting to our evaporating experiment at the 
 Gutta Percha Works ; the pressure being 40 Ibs., 
 the temperature of the steam and, of course, the 
 water also, was at about 288 Fahr. In order to 
 compare with the ordinary practice, the evaporation 
 of 11*1 to 1 must be reduced to what it would be 
 were the boiler supplied at the ordinary standard 
 temperature of 100, which, by the Admiralty rule 
 for that purpose, assuming the latent heat of water 
 at 1000 is as Mows : 
 
 (1212 actual temp. 288 Q ) X 11-1 q . 2 ]h 
 (1212 - standard temp. 100) = 1112 " 
 
 water to one of coal. 
 
 It is proper to state that the rate of combustion 
 did not much exceed 10 Ibs. of coal per square foot 
 of grate bar per hour, and that the experiments were 
 repeated in the presence of several f competent wit- 
 nesses, occasionally reaching a corrected evaporation 
 of 10 Jibs, of water to 1 Ib. of coal; or, in other 
 words, a Galloway boiler made a common variety of 
 bituminous Newcastle coal, in ordinary practice, go 
 as far as the best Welch in a pet experiment with the 
 far-famed Cornish boiler.1 
 
 In order to arrive at the best proportions to be 
 
PROPORTIONS OF THE BOILER. 41 
 
 observed in a boiler of this kind, we have ample 
 experience to rely upon. Besides the experience 
 afforded by the great number made by Messrs. Gal- 
 loway, both for land and steamboat purposes during 
 the last three or four years there is a sufficient 
 number of them in the metropolis for the purpose of 
 illustration. The dimensions of the boiler at the 
 Gutta Percha Works, above referred to, where the 
 evaporation experiments were made, are as follows : 
 Length of boiler 30 feet 3 inches. Diameter of 
 ditto inside, seven feet. Greatest diameter of main 
 flue, 4 feet 6 inches inside, by 3 feet deep, con- 
 taining 13 conical water tubes, each 11 inches inside 
 diameter at top, and 9 inches at bottom, which tubes 
 act as prop stays between the flat top and bottom of 
 this main flue. The entrance to this main flue is by 
 two parallel and similar furnace tubes, each 8 feet 
 long, and somewhat oval in section, being 2 feet 6 
 inches wide, by 2 feet 9 inches deep* But they are 
 stronger than if they were circular, on account of 
 containing three strong cast iron bearing bars for 
 supporting the grate, which act as prop stays from 
 side to side. The fire-grates are each 7 feet 4 inches 
 long, by 2 feet 6 inches wide, containing about 
 | square foot of fire bar area per horse power for the 
 
42 PROPORTIONS OF THE FIRE GRATE. 
 
 50-horse boiler. Each of the furnaces contained 
 two lengths of fire-bars, the front bars being 1 inch, 
 and those at the back 1J thick with f -inch spaces 
 between them in both cases. This pitch of the 
 bars was adopted without my concurrence, other- 
 wise I should have preferred the front bars -inch 
 thick, with the same spaces, and the back bars with 
 J or five-sixteenth spaces, instead of f , in order to 
 attain a more perfect combustion of the smoke ; that 
 being the object for which Messrs. Galloway ori- 
 ginally adopted the double furnace plan. These 
 grates have since been replaced by Miller's (now 
 expired) patent moveable bars as improved by Mr. 
 Annan for Mr. Chanter, the proprietor of that patent, 
 that is by making every alternate bar, only, moveable 
 by hand, instead of the whole set, when each adjoin- 
 ing bar moved alternately in opposite directions, 
 according to the mode originally patented by Mr. 
 Miller; These moveable bars, in some measure, 
 answer the same end as the thin bars; that is, of 
 increasing the rate of combustion and, of course, 
 increasing the evaporating power of the boiler, at the 
 expense, perhaps, of a little smoke, which, however, 
 may consist with the most perfectly attainable econo- 
 mical combustion of the fuel. 
 
JARGON OF SMOKE PATENTEES. 43 
 
 " Perfect combustion/' and the action of a " per- 
 fectly smokeless furnace/' are very far from being 
 synonymous, or even similar phenomena, and produce 
 very different, and, sometimes, widely opposite results, 
 both chemical and physical, not always likely to be 
 recognised by every noisy patentee or pretender who 
 takes his chemistry like his physic, from the pharma- 
 copoeia. In some conspicuous instances, at least, 
 the philosophical jargon employed really encumbers 
 the path of science and progress and, finally, becomes 
 a much greater nuisance than the smoke which 
 these mock-philosophers pretend to subdue. 
 
 So far from perfect combustion, and perfect smoke- 
 lessness, in a steam-engine furnace being identical, 
 they are, very commonly, the antithesis of each other; 
 perfect combustion being the most completely effected 
 when the whole of the oxygen passing through the 
 grate, is the most nearly or perfectly used up in com- 
 bining with the hydrogen and carbon of the fuel, 
 although it may be occasionally accompanied by the 
 inappreciably small loss of a few uncombined atoms 
 of the latter substance in the form of smoke or soot, 
 which in fact it is, in a finely divided and impalpable 
 state, merely giving a black colour to the nitrogen 
 and other useless incombustible gaseous products of 
 
44 STRENGTH OF GALLOWAY* S BOILERS, 
 
 the furnace. These products must pass off, visible or 
 invisible, at whatever cost, although we question, were 
 it possible to collect all the fuel in a large volume 
 of visible snioke many hundreds of miles in extent, 
 whether it would amount to a single ton of coals. 
 A smokeless furnace, however, on the other hand, 
 when the result of a thick fire, thick bars, and slow 
 combustion may, and frequently does, occasion a 
 loss of a large part of the carbon of the coal, which 
 passes off by the chimney, only half-burned, in the 
 shape of perfectly invisible carbonic-oxide-gas, thus 
 creating a dead loss of 25 per cent, in coal. This 
 evil, however, admits of prevention in these double 
 furnaces, and by other simple means, 
 
 As to the strength of this boiler, the furnace-plates 
 are of Low Moor iron, f-inch thick, the flue and 
 shell, of the same thickness $ the best Staffordshire, 
 and the flat ends, -^inch* The ordinary working 
 pressure of the steam being about 35 Ib. per square 
 inch, gives a strain of about 4000 Ib. on each square 
 inch sectional area of the iron in the circular part of 
 the shell, leaving a surplus of about lOOOlbs. per 
 square inch greater strength in that part of the boiler, 
 which is equal to withstand a higher pressure of steam 
 by 25 per cent., and we may be still assured that 
 
SUITABLE FOE HIGH-PRESSURE STEAM. 45 
 
 the boiler is not strained to one sixth of its ulti- 
 mate power of elasticity, that being taken at about 
 20,000 Ibs. per square inch of sectional area. 
 
 One object of adducing this case of a Galloway 
 boiler at such length is to show the propriety of using 
 a much higher pressure of steam than has hitherto 
 been usual, or much practised in marine boilers, as 
 well as the safety of those boilers for that purpose, 
 and it is proper to state that the strength of the plates 
 as above given is now found, after a trial of five years, 
 constant work, amply sufficient for every purpose, 
 with engines requiring steam from 40 to 50 Ibs. 
 pressure. This boiler has been, during that time, 
 which may be said to be nearly equal to 10 years' 
 working the ordinary day work in a regular factory, 
 and under the various vicissitudes commonly atten- 
 dant on night and day working, it has not sustained 
 a single casualty, and not even a leakage of any kind 
 that could be discovered after the most careful in- 
 spection. My own personal examination was parti- 
 cularly and frequently directed to the upper end of 
 the vertical tubes where the flame impinges with its 
 greatest intensity immediately after passing over the 
 furnace bridge. This particular part having been 
 pronounced by all practical boiler makers as being 
 
46 STRENGTH OF GALLOWAY^S BOILERS. 
 
 the most vulnerable point in other vertical tube boil- 
 ers. I, in consequence, subjected it from time to 
 time to the most scrupulous examination ; the result 
 on the whole has been so satisfactory that I now ven- 
 ture to recommend this plan of boiler as pre-eminently 
 suited to marine purposes. Should any doubt remain 
 on the mind of any engineer as to the power of the 
 " elliptical" flue, as it has been wrongly called, to re- 
 sist collapse from 150 Ib. pressure, that doubt can 
 only apply to the segmental or semicircular portion 
 of its sides, the flat top, supported by any adequate 
 number of tubes being impossible of collapse ; there 
 is one exception which may be stated in order to re- 
 move such doubt. And as exceptions sometimes 
 prove the rule, this one will serve to corroborate our 
 opinion, already expressed, as to the much greater 
 strength of this form of boiler than those of the 
 "Pacific," " Baltic," and others with longer vertical 
 water tubes, and which therefore have the sides of their 
 main flues, of greater depth, and consequently weaker. 
 The exception is, that only a single case has occurred 
 in the whole range of Messrs. Galloway's extensive 
 practice in the manufacture of those boilers, where 
 collapse in the flue took place, and on that occasion, 
 as appeared from the report of another engineer, was 
 
OTHER EXAMPLES OF BOILERS. 47 
 
 clearly attributable to this portion of the flue having 
 (from some unaccountable caprice) been made nearly 
 flat, or at least with a very great radius of curvature. 
 The proper curve, however, for this portion of the 
 flue it is very clear should be a semi-cylinder, or a 
 portion of one, of the same radius as the top of the 
 furnace tube, when of the same thickness, they being 
 both subjected to the same pressure. 
 
 Besides other and larger boilers on the Galloway 
 plan at the Gutta Percha works, I have also erected 
 several of various sizes at other places, in which per- 
 haps better proportions were attained. 
 
 Two such boilers have been working for nearly four 
 years past at the London Zinc Mills more success- 
 fully perhaps, and with greater economy than has 
 ever before been obtained with any other description 
 of boiler, under similarly unfavourable circumstances. 
 The dimensions of these two boilers are precisely the 
 same, and are as follows : Length, 24 feet ; Dia- 
 meter, 7 feet. Greatest diameter of main flue, 5 feet 
 7 inches, which flue contains 21 vertical water tubes, 
 11 J in. diameter at top, 6 in. at bottom, and 2 feet 
 10 in. long. These tubes are three-sixteenths thick, 
 welded, and placed zigzag fashion, so that a man may 
 creep easily along each side of the flue, and sweep in 
 
48 DESCRIPTION OF MODE OF SETTING. 
 
 amongst them. The boilers are placed upon a num- 
 ber of fire brick blocks, or short columns, 18 inches 
 high, 9 inches diameter, and 18 inches apart, so that 
 the whole of the lower half of the external shell of 
 the boiler, except where it rests on the columns is 
 exposed to the smoke and hot air in the flame bed. 
 The flame and smoke thus pass through among these 
 columns immediately after passing through the main 
 internal flue tube, and then dip underneath the ash 
 pit, in order to pass into the chimney flue. Conse- 
 quently the products of combustion, after proceeding 
 from the furnaces, make but one return to the front 
 of the boiler before passing off to the chimney, which 
 happens to be situated near the front end of the 
 boiler. The fact of the very great economy of these 
 two boilers with this mode of setting, so very opposite 
 to the Cornish, and indeed the too usual system of 
 several returns of long winding flues, to which system 
 it is in my mind utter condemnation, would justify 
 any one, cognisant of this case, to set up such boilers 
 in the direct manner, or without any return flues 
 whatever. This circumstance shows the suitability of 
 these boilers for marine purposes where no external 
 flues can be admitted. 
 
 The 4 furnaces of these 2 boilers are each 7 feet 
 
STRUCTURAL DETAILS OF BOILER. 49 
 
 6 inches long, by 2 feet 9 inches diameter, and 2 feet 
 11 inches deep, composed of Low Moor plates five- 
 sixteenths thick. Each of these furnaces contained 
 3 lengths of fire bars, each about 2 feet 2 inches 
 long, % inch thick, and f inch spaces between them, 
 making about f of a square foot area of fire bar sur- 
 face for each nominal horse power of the boiler, that 
 being called 55 horse. 
 
 The external circular shell of the boiler is f inch 
 thick, and the ends seven- sixteenths of Stafford- 
 shire plates, " Thorney croft's best best crown iron." 
 The flat ends are stiffened by angle irons riveted 
 across from side to side, midway between the flue and 
 the top, and from these proceed stay bars 6 feet long, 
 riveted in a sloping direction to the top of the boiler. 
 Besides these, each end is further strengthened by 4 
 " gussett " or angular plate stays. The angle irons 
 round the ends are 3| inches broad, and the rivets 
 are 2 inches pitch. Each boiler is surmounted by a 
 cylindrical horizontal steam " dome" 10 feet by 3 feet, 
 with curved ends, the same thickness of iron as the 
 boiler. This dome is riveted to the boiler by 2 cast 
 iron necks, or short pipes 10 inches long by 8 inches 
 diameter. To these domes the steam pipes are attached. 
 One 5 inches flat disk lever safety valve ; and one 
 E 
 
50 BOILERS OF ROLLING MILLS. 
 
 glass water gauge is attached to each boiler, but no 
 float gauge nor self acting feed. 
 
 These two boilers were employed to drive two 40 
 horse engines of the ordinary Boulton & Wattf s 
 construction, made by Peel, Williams, and Peel, of 
 Manchester; 34 inch cylinders, 6 feet stroke, and 
 20 turns a minute, working together a little over 200 
 indicated horse power, which they ordinarily did 
 with less than 3 Ibs. of coal per horse power per hour. 
 The steam, being 35 to 45 Ibs. in the boilers, is cut 
 off by the governor and double beat throttle valve 
 instead of a separate expansion valve, at an average of 
 about \ to \ the stroke. 
 
 It is perhaps useful to mention that the peculiarly 
 sudden action of this double beat or equilibrium 
 valve, when used as a throttle valve, has always a 
 tendency to cause priming, much more than the 
 ordinary spindle throttle valve of Boulton and Watt. 
 This, together with the nature of the work carried on, 
 that of rolling thick lumps of metal, called signifi- 
 cantly enough "breaking down," and thin sheets 
 called " finishing," where very great irregularity of 
 resistance is inevitable, involves the necessity of 
 keeping the steam very much higher in the boiler 
 than is required in the cylinder ; the steam in the 
 
 1 
 
CONDITIONS UNFAVOURABLE TO ECONOMY. 51 
 
 cylinder seldom ranging so high as 20 Ibs. per square 
 inch, while in the boiler it is from 30 to 40 Ibs. The 
 ever varying resistance caused by these lumps and 
 sheets of metal passing through two, three, or four 
 pair of rolls, at the same time, is one of the unfa- 
 vourable circumstances for economy before alluded to. 
 Another circumstance, unfavourable to very great 
 economy in this case, was the draught, which, although 
 the chimney is of sufficient elevation and capacity, 
 was much injured by communication with other 
 furnaces and fire-places, some of them open ones, 
 which, without great care in, or total absence of 
 stoking or stirring the fire, made it impossible to pre- 
 vent some smoke at particular times, especially after 
 the fire doors had been thrown open, and the furnace 
 too much cooled. Although valves were applied for 
 admitting air at the bridges of the four furnaces of 
 these boilers, by which all dense smoke was thereby 
 entirely prevented for a period of three or four months, 
 and a certificate was obtained from Sir Eichard 
 Mayne, the chief inspector under the Metropolitan 
 Smoke Act, to that effect. Yet no sooner was there 
 an occasion to change the fireman, for a more indus- 
 trious stoker, than the smoke again appeared, and 
 the owner was convicted, unjustly, as I think, in a 
 
52 CONDITIONS UNFAVOURABLE TO ECONOMY. 
 
 penalty under Lord Palmerston's Act. It is unneces- 
 sary to add that the greatest economy of these boilers 
 in fuel was before the Smoke Act came into operation. 
 In addition to this,, the situation of the boilers was 
 such as necessitated the " dipping" of the flue con- 
 siderably,, in order to enable it to pass beneath the 
 ash pit, which is well known to be extremely detri- 
 mental to draught. Notwithstanding all those draw- 
 backs against the probability of a good performance 
 with,, at that time, nearly a quite new kind of boiler, 
 these boilers have continued to work four years without 
 mishap or difficulty of any kind nearly two years of 
 that time night and day at the same extremely econo- 
 mical rate. 
 
 More practical reasons of the like kind might be 
 here given; but what has been already advanced may 
 be considered sufficient to warrant the conclusion that 
 this plan of boiler might at once be applied as a 
 marine boiler, with the greatest propriety and moral 
 certainty of success. For this purpose the boiler will 
 require very little modification from the form indicated 
 by the above description. If any deviation be neces- 
 sary, I would advise that for 60 or 70 Ibs. pressure 
 the diameter should be reduced to between 5^ and 6^ 
 feet, and to meet the exigencies of working with salt 
 
 
BOILERS AT GEEAT EXHIBITION. 53 
 
 water, besides using the ordinary surface " blow off," 
 and other similar appliances,"* we would make all the 
 plates one- sixteenth inch thicker throughout. If 
 required to work nearly or quite up to the maximum 
 pressure of 100 Ibs., then all the parts admitting of 
 it should be double riveted, and the rest welded. 
 
 THE EXHIBITION BOILEB, OF 1851. 
 
 Ill recommending that the diameter of a high 
 pressure Galloway Boiler should be about 6 feet, it is 
 not without due consideration, and considerable ex- 
 perience of various precedents that I offer this recom- 
 mendation. One such boiler may now be referred to, 
 belonging to the West-Ham Gutta Percha Co. of 
 West Street, Smithfield, by whom it was bought of 
 the Commissioners of the Hyde Park Exhibition of 
 1851, where it had been worked during the 6 months 
 
 * Lamb's " Surface blow-off apparatus," as described in 
 Murray on " Marine Engines," 1852, or my Boiler Cleaning 
 Machine, as described in my Essay on Boilers in 1838, and 
 first figured L in the Artisan Club's " Treatise on the Steam 
 Engine," in 1844, may be used indifferently as they are 
 substantially the same thing intended for different purposes ; 
 the object of the former being to prevent scale, and that of 
 the latter to prevent priming. 
 
54 BOILERS AT GREAT EXHIBITION. 
 
 that the Exhibition was open. And, although only 
 one of nine boilers of about equal power used for the 
 purpose, it supplied as nearly as could be estimated, 
 about one third of the whole of the steam used in that 
 building. To young engineers, who usually take 
 theory before practice, it may be as well to state that 
 my reasons, when consulted on the subject, for fixing 
 on 6 feet as the most fitting diameter for this Exhibi- 
 tion Boiler, were, in the first place, that with that 
 diameter, according to the rules already given by me, 
 a f inch plate is of ample strength for a working 
 pressure of 40 Ibs. per square inch ; that being the 
 steam pressure recommended by Sir W. Cubitt, and 
 the other Commissioners, not to be exceeded, and from 
 whom I obtained at last, with some little perseverance, 
 their consent to exhibit this boiler, a difficulty created 
 through some mistake, by which four boilers of a diffe- 
 rent kind had been previously ordered. It was then 
 erroneously supposed that those 4 boilers which were 
 of the multitubular class, though without fire boxes, 
 blast pipes, or large chimney for draught, would have 
 furnished an ample supply of steam for all the pur- 
 poses of the exhibition ; but in this power, as the event 
 proved, they were utterly deficient, not producing 
 even half the quantity of steam required, so that this 
 
BOILERS AT GREAT EXHIBITION. 55 
 
 Galloway Boiler was considered only as a supernu- 
 merary one a circumstance which gave a very instruc- 
 tive lesson to the railway and other engineers who 
 had the principal share in managing the preparations 
 for working the machinery on that occasion ; and the 
 result was thai four additional boilers had to be supplied 
 in great haste by the same contractor, making in all 
 eight of the multitubular variety, and one Galloway 
 Boiler, before an adequate supply of steam was 
 obtained. Although had the architectural and deco- 
 rative portion of the Commissioners consented to the 
 erection of a brick chimney, which would have been 
 quite in keeping with the engineering and scientific 
 object of the Exhibition, instead of nine boilers, 
 any three of them would have been sufficient, 
 besides giving an excellent opportunity of exhibiting 
 a variety of smoke-burning inventions which were 
 thereby virtually ignored. As it was, there was a 
 petty exhibition of locomotive chimneys, a few feet 
 in height with one exception, the funnel of a marine 
 boiler, only 20 feet high, which in spite of some 
 opposition I succeeded in having erected to the Gallo- 
 way Boiler we are now describing. 
 
 The pressure of the steam being limited to 40 Ibs. 
 per square inch, a f -inch plate will only have a ten- 
 
56 BOILEES AT GEE AT EXHIBITION. 
 
 sile strain upon it of something less than 4000 Ibs. 
 per square inch, sectional area of the iron. The 
 formula for the strength of boilers winch I usually. 
 
 is 2 st 
 employ , jp=- - where s is the strain which, in 
 
 Cv 
 
 this case=4000 Ibs., =the thickness of the metal in 
 inches,=*375 or f , and <^=the diameter of the boiler, 
 72 inches, or, 
 
 - 
 
 will be the pressure of the steam allowable Avith these 
 dimensions ; and I have no doubt whatever that 
 double that pressure might have been put on with 
 perfect safety, so far as the tensile strain on the 
 circular portion of the boiler is concerned. 
 
 Another reason for the particular dimensions of 
 this boiler was, that, besides knowing well what a f 
 plate will bear, it is so very much used that the pro- 
 per thickness for securing the best workmanship can 
 readily be obtained. 
 
 There needs, perhaps, no excuse for having made 
 this boiler "stronger than strong enough," seeing 
 that it was to be erected in the close vicinity of so many 
 thousands of persons, daily assembled in the Exhibition 
 building, which was, of itself, a matter of no little 
 
RELATIONS OF STRENGTH AND QUALITY. 57 
 
 responsibility, for it was considered good policy not 
 only to be perfectly safe, but also to enable the 
 general public to feel themselves safe, by an assurance 
 of a surplus of strength so far beyond any possible 
 requirements. 
 
 Por ordinary commercial purposes, however, where 
 people generally know what they are about, as 
 well as for warlike and other government purposes, 
 where they ought to know, if any where, this very 
 inordinate precaution is out of place. And although 
 I have, both by precept and example, recommended, 
 in common with many other engineers, 4000 Ibs. for 
 "best" Staffordshire, and 50001bs. per square inch 
 strain for Yorkshire iron, as a safe rule to be adhered 
 to by boiler-makers ; I am now inclined to modify 
 that opinion. By fixing too low a standard for 
 strength of iron structures generally, the result has 
 been to induce the manufacture of very inferior and 
 low-priced qualities of iron, which are substituted for 
 the best in many situations where detection of the 
 inferior quality is difficult ; and, so long as such infe- 
 rior qualities reached the low standard required for 
 the best, at a much higher price, an inducement is 
 gradually being created among boiler-makers to 
 believe that, in many instances it is only " the name 
 
58 RELATIONS OF STRENGTH AND QUALITY. 
 
 of the thing," which their customers are desirous of 
 paying for. Hence the various designations of 
 " best " and " best best iron," although the latter, in 
 some cases, signifies the worst of two or three qualities 
 made at the same place. As f of an inch is a 
 kind of standard thickness to refer to, and the 
 kind called " Thorney croft's best crown " is so well 
 known, it is proper to state that, not only has the 
 boiler already referred to been working at from 50 to 
 60 Ibs., but several other boilers of the same kind 
 of iron, same thickness, made by the same makers, 
 and in every way similar, except in being 1 foot more 
 in diameter, (which would be equivalent to an increase 
 up to from 60 to 70 Ibs. upon this 6-foot boiler,) have 
 been working nearly the same length of time, and 
 they are working now with perfect impunity, at the 
 same pressure. Those boilers were all tested at the 
 injudicious pressure, in my opinion, of " three times 
 their working pressure" 
 
 There is an universal prejudice among engineers 
 in favour of this "treble proof" of the strength of 
 a boiler. This Exhibition boiler, for instance, was 
 thus proved, in the presence of one of the Eoyal 
 Commissioners, at 150 Ibs. per square inch, which 
 pressure, in the Commissioner's and the maker's 
 
RELATIONS OF STRENGTH AND QUALITY. 59 
 
 opinions, was required to justify them in working it 
 at 50 Ibs., although, in an ordinary case, 120 Ibs. 
 would have satisfied them when the working pressure 
 was intended to be only 40 Ibs. Now I am not 
 going to contend that the least injury was likely to 
 be sustained by this particular boiler exposed to so 
 severe a strain; but I wish to point out the absur- 
 dity and injurious consequences likely to arise from 
 the prevalence of such a dogma when applied to very 
 high pressures, however safe it has always been at low 
 ones, say under 10 Ibs., or, at most, up to 20 Ibs. 
 per square inch. 
 
 If, instead of moderately good Staffordshire plates, 
 capable, we may suppose, of bearing a tensile strain 
 of 20 tons per square inch section before breaking, 
 we have a boiler to test made of an inferior quality of 
 iron, say only capable of supporting 16 or 17 tons, 
 which was found by Mr. Lloyd to be the ultimate 
 strength of the iron of the boiler of the " Cricket " 
 steamboat that exploded on the Thames, in 1847 ; 
 and if as was proved by Mr. Lloyd, in that case, by 
 direct experiment on the corresponding boiler, every 
 way similar to the exploded one, namely 5 feet diameter 
 and | -plates, that the latter was severely strained 
 close to the bursting point, and permanently injured 
 
60 BOILER OF THE STEAMER "CRICKET." 
 
 by the application of 1361bs. per square inch, giving 
 a reduction of about 40 per cent, for the riveted, 
 below the original, or solid plate, as tested by him, 
 in strips of 2 inches broad. We have only to 
 suppose that our Exhibition boiler had been of the 
 " halfpenny boat Cricket" quality, and if tested at 
 three times the intended pressure, or 120 Ibs., which 
 it might have passed safely, perhaps, once, and after- 
 wards worked, without suspicion, at 40 Ibs., although 
 in reality, weakened by the process so much as to 
 become dangerous, even at 60, and it might explode 
 at half-a-dozen or so pounds higher pressure. If 
 such a result may follow such a practice, what, it may 
 be asked, would be a safer mode of proceeding ? I 
 answer, from the results of my own practice, as 
 follows ; I would have taken a mean point in the 
 above supposed case, between 40 Ibs., the working 
 pressure, and the estimated strength of the iron, say 
 140, which would be at 90 Ibs., and make that the 
 point at which to test the boiler. That is not much 
 more than double, in fact, 120 per cent., above its 
 working pressure, namely 50 Ibs., as well as being 
 also 50 Ibs. below the estimated strength of the iron; 
 and supposing the life (as it is called) of such a boiler 
 to be estimated at 5 years, then this proof test ought 
 
BOILER OF THE STEAMER "CRICKET." 61 
 
 to be reduced by equal instalments of 10 or 15 Ibs. each 
 year. Now who will say that, if such a course of 
 procedure, or some similar one, had been made 
 compulsory by legal enactment, before the " Cricket " 
 explosion, that that "accident," and many others, 
 would not have been avoided ? But as we are, so far, 
 only dealing with probabilities, we may take the 
 actual pressures used in the " Cricket," namely, 
 working pressure, as proved at the inquest, 66 Ibs., 
 the bursting pressure, as proved by Mr. Loyd's 
 
 -j O f* I f f* 
 
 experiments, 136 Ibs., which gives a mean of 
 
 & 
 
 =101 Ibs. for the testing point, or about 50 per cent, 
 only, above the actual working pressure. By this, it 
 will be seen how much safer a test of this proportion 
 would have been, than the treble test. 
 
 I have stated in a previous work, that a test of 
 double the working pressure was amply sufficient, but 
 I by no means wished it to be inferred that such a test 
 should be considered to be necessary, or useful, 
 except at moderately low pressures. In my notes to 
 the edition of " Tredgold on the Steam-engine," pub- 
 lished in 1852-3, I regret having overlooked what I 
 consider a dangerous error in that author, although 
 he admits that double the working pressure is a suffi- 
 
62 FALLACIES IN TEEDGOW/S WORK 
 
 cient test for low pressure boilers, lie states that " it 
 becomes insufficient in high pressure boilers, because 
 they have a smaller amount of steam room," and 
 actually gives a formula for calculating the excess of 
 strength which he would give to a boiler on that 
 account, saying, " If one boiler contains 20 cubic feet 
 for each horse-power, and another only 10, the boiler 
 with only ten feet of space should be of twice the 
 strength." It is scarcely necessary to point out how 
 TBEDGOLD confounds, here, two entirely different 
 objects ; one, the prevention of injury to boilers by 
 excessive strain in testing them ; the other, the hav- 
 ing such an excess of strength as " to provide against 
 accident in the event of the valves being out of 
 order," &c. (Page 268.) Trusting that these remarks 
 may, in some small degree atone for the share I took 
 with others much more competent, in delaying a little 
 longer the descent into oblivion of this heterogeneous 
 work of "Tredgold on the Steam-engine," I shall 
 return to the description of the Galloway Exhibition 
 boiler. 
 
 If as I think I have made manifest, this 6 feet 
 boiler of f Staffordshire iron, with the ordinary lap 
 and single-riveted, be equal to a working pressure of 
 70 Ibs. per square inch, then it may safely be asserted 
 
ON THE STEAM ENGINE. 63 
 
 tliat a boiler of the same shape and dimensions of Low 
 Moor or Bowling Iron, one-sixteenth of an inch 
 thicker, and double-riveted, welded indeed where 
 necessary, and judiciously stayed, would be abun- 
 dantly safe to work in a steam ship at the maximum 
 pressure of 100 Ibs. 
 
 That such a boiler for such a purpose would be 
 very decidedly superior in every respect to any form 
 of marine boiler at present in ordinary use for large 
 steam ships, scarcely admits of a question with any 
 one understanding the subject; and those who do 
 not may have the clearest of proofs in the performance 
 of the land boilers I have referred to, as well as that 
 of many others on the same principle, now spread all 
 over the country. 
 
 We contend for the adoption of the correct 
 principle which we know that these boilers con- 
 tain. And as certainly as is the truth of any 
 common rule in arithmetic demonstrable to those 
 who consent to examine the proof, so certain is it in 
 my apprehension that any expedient, which supersedes 
 the present flue and multitubular marine boilers, will 
 very considerably accelerate the passage between this 
 country and America. If this be accomplished even 
 only by a single day of the nine that is yet required, a 
 
64 IMPORTANCE OF IMPROVED BOILERS. 
 
 great object will be attained for the progress and wel- 
 fare of the people of both countries. That such an 
 achievement is a point worthy of any man's ambition, 
 we need not insist on or that of any number of men, 
 on either or on both sides of the Atlantic. To shorten 
 the way to America, by reducing the time now occu- 
 pied at the rate of only 10 per cent, per annum for the 
 next 4 years, would solve a problem of immense social 
 importance. It would in four years time lay us along- 
 side our friends and brothers in the United States in 
 six DAYS ! That this will yet be accomplished, there 
 can be little doubt ! Experiments in fact are already 
 in progress with this end in view. To reach New 
 York in six days is an object far above any partisan 
 or even national views, nor is the benefit wholly 
 measurable by the pecuniary or commercial advantages 
 attained. For it is by such achievements that nation 
 is to be knit to nation by bonds of undying brother- 
 hood, and the advent is to be hastened of that peace- 
 ful kingdom, the clarion of whose renown, and the 
 majesty of whose sceptre, will command the joyful 
 homage of mankind. 
 
 On a subject of such vast interest as a material im- 
 provement in the art of steam navigation, every 
 engineer, sailor, and shipwright, has some crotchet 
 
AND FIRE-FEEDING MACHINERY^ 65 
 
 of his own. I confess not to be singular in this re- 
 spect, and -some of my plans of improvement have been 
 not confined to paper. They have embraced both 
 engines and propellers, but have principally been 
 devoted to boilers and to furnaces. Though certainly 
 I have never been guilty of trying to help a ship on 
 her way to America by burning smoke, the miscarriage 
 caused by which was subsequently visited upon un- 
 offending parties. 
 
 The merit of that abortive attempt lies with Mr. 
 Charles Wye Williams, so well known for his nostrums 
 in smoke prevention, and the untiring energy, usually 
 appertaining to such adventurers. That a properly 
 constructed Fire-feeder, which would supply the 
 furnaces without involving the necessity of opening 
 the fire doors, or admitting air except through the fire 
 bars, would be of great advantage, and abolish the 
 slavery of the stoke-hole, no one can deny. But that 
 would be irrespective of any smoke- consuming or 
 preventive properties it might possess ; which, however 
 desirable should not be allowed to engross our first 
 attention. Feeding and stoking the fire, however, 
 have long been accomplished by very simple machinery, 
 on the principles of Stanley and Walmsley, and 
 Miller. All the three inventions are now public pro- 
 F 
 
66 EXHIBITION BOILER 
 
 perty ; the patents having long since expired ; and, 
 alas, the patentees, whom I knew well, have ex- 
 pired also. They were thoroughly practical engineers, 
 and their inventions were entirely successful on land, 
 as they would have been on sea also had an oppor- 
 tunity been afforded for their trial. Those appliances 
 to a suitably constructed marine boiler it is under- 
 rating them to say would increase the boiler power of 
 the steam ship by 10 per cent., as they have always 
 done that of the steam mill on land by double that 
 amount. 
 
 These, and many such equally valuable inventions, 
 not the speculations of mere " science-mongering " 
 amateurs, or paper engineers, but the actual tried 
 and proved productions of practical operative mecha- 
 nics, lie at hand ready for application to every emer- 
 gency that can possibly arise in the development of 
 that improvement of steam navigation now so urgently 
 required. 
 
 "Where there is a will there is a way," is an 
 axiom in mechanics, as in other things, if there be 
 money. As a sample of the mode of proceeding in 
 the choice of an improved boiler, let any plain busi- 
 ness man or merchant, he need be neither an engineer 
 nor man of science, obtain a ten minutes interview with 
 
IN SITITKFIELD. 67 
 
 the manager of tlie West-Ham Gutta Percha Com- 
 pany, at their extensive works in West Street, Smith- 
 field; or let him go to any other factory of which there 
 are several in London, where the Galloway Boilers 
 have been working for several years ; for, I perhaps 
 take a liberty in referring to this one more than 
 others, which I have done from its central position in 
 the city, and its having been so well known for many 
 years as the Iron Works of the late Alexander Gallo- 
 way and Sons, the eminent engineers, formerly of this 
 country, but now of Egypt. He will there see the 
 original Exhibition Boiler at work, which, I have the 
 authority of Mr. Walter Hancock, of the Gutta Percha 
 Company for stating, has been working under his 
 superintendence almost uninterruptedly four or five 
 years since the closing of the Exhibition a great 
 portion of that time working night and day, and fre- 
 quently at the extreme range of pressure; this too 
 without any deterioration from use. A few minutes' 
 inspection will bring entire conviction of the accuracy 
 of what we state. The visitor will there see a greater 
 quantity of steam produced by a comparatively small 
 boiler, which might if necessary be fixed aboard a 
 steam ship, and at work in a few days, at a greater 
 pressure by two or three times over than is now 
 
68 GOOD BOILERS EASILY MANAGED. 
 
 generally attainable in the present marine boilers. 
 Withal, too, at the cost of a much less quantity of 
 very inferior coal than is at present required perhaps 
 by any other description of boiler, even on land. He 
 will see all this done without the fussing, stewing, 
 and sweating of the present barbarous stoke-hole prac- 
 tice aboard ship, which too many people think a 
 necessary concomitant of all marine steam engines. 
 On the contrary, he will see the work done quietly, 
 with cleanliness and easily; and the black smoke 
 "perfectly consumed" into the bargain, without the 
 intervention of any smoke consuming apparatus of 
 any kind, patent or otherwise; no air being admitted 
 to the furnace except what passes through the fire 
 grate ; and he will instantly ask himself, is all this 
 applicable or possible in a steam ship ? My answer 
 to such a question is, that it certainly is, excepting 
 merely the tall brick chimney, the want of which 
 would only affect the ability to consume inferior fuel, 
 or the prevention of a little smoke, but which quali- 
 ties, if thought important, may be easily retained by 
 the introduction of a small blowing fan. 
 
VALUE OF BRICK FIKE-PLACES. 69 
 
 THE ELEPHANT BOILER. 
 
 Having disposed of the question, how steam can 
 be best obtained at a pressure, or nearly up to a 
 pressure of 100 Ibs. per square inch, and that in 
 boilers with internal furnaces, thereby permitting 
 their use in wooden ships where necessary, we come 
 now to the requirements of 100 Ibs. pressure and 
 upwards. For this purpose we anticipate the neces- 
 sity of an iron ship. The reason for this is, in the 
 first place, that to enable boilers, of a given thickness 
 and strength of material, to stand a double pressure ; 
 they must be just half the diameter therefore it is 
 necessary to have external instead of internal furnaces. 
 It is an inevitable law that the strength of the shell 
 of a cylindrical boiler is inversely as its diameter ; or 
 in other words, if we find a 6 foot diameter boiler 
 with a | shell to stand 60 Ibs. pressure, then we 
 may be assured that a 3 foot boiler will stand 120 Ibs. 
 pressure, or nearly so, under the same circumstances. 
 In the second place, the full value in heat, from any 
 kind of fuel, cannot be obtained without the inter- 
 vention of fire brick, or other non-conducting sub- 
 stances, but with which it would be quite impracti- 
 cable to line the present marine boiler furnaces ; or in 
 
70 ELEPHANT BOILER SUITABLE 
 
 fact almost any internal furnace for commercial pur- 
 poses, although we recollect the case of an iron fire 
 box boiler, erected to heat a new church in Man- 
 chester some years ago, having its steam-genera- 
 ting power nearly doubled by simply putting in a 
 fire-brick lining round the fire grate ; thus prevent- 
 ing the refrigerating effect on the fuel and flame pro- 
 duced by the close contact of the water- casing and 
 bridge of the fire-box. Many good smoke burners 
 have been made simply by inserting a few fire-bricks 
 in this way thus as it is called concentrating the 
 heat. 
 
 By making a small boiler, we make a strong boiler ; 
 and by making a brick furnace, we make a hot fire. 
 
 In adopting the elephant principle for a marine 
 boiler, we get both these advantages, a small diameter 
 and an external furnace ; but, besides that, we get 
 a large width of fire-grate, and the convenience of 
 using firing machines. Moreover, as the resistance 
 is more dependent on the width of the ship than its 
 length, it is incumbent to occupy the entire beam 
 dimensions of the vessel without the intervention of 
 water-legs between the furnaces, if we require the 
 maximum power of the boilers, when they are arranged 
 transversely across the ship. This the elephant boiler 
 
FOE MARINE PURPOSES. 71 
 
 gives us the means of doing with advantage. A range 
 of 3 or 4 boilers may be thus made to occupy the 
 whole breadth of the vessel, with nothing beyond 
 a thin fire-brick wall between the furnaces. The 
 proper physical management of the furnaces is a 
 matter on which far more reliance ought to be placed 
 for increasing the power of steam ships than is dreamt 
 of by any of our " chemically considered" combustion 
 patentees. It is not undervaluing science, but the 
 contrary, to maintain this; in which I shall be joined 
 by Earaday, as I was by John Dalton, when living. 
 To encourage a fireman to work by tact and judg- 
 ment not by empirical rule, to become dextrous, 
 watchful and discriminating, is surely of more use 
 than to cram him with the jargon of science, which 
 would leave him as useless a member of society as 
 those who are already thus distinguished. Chemical 
 diagrams, and the atomic system of philosophy, will 
 give little aid in keeping up the steam, and those who 
 are chemists among stokers, and only stokers among 
 chemists, will lend little aid to the advancement of 
 either art. 
 
 Although the elephant boiler is, perhaps, more 
 popular in France, and on the Continent, generally, 
 where it was introduced by Woolf himself, many years 
 
72 ELEPHANT BOILEE IN SPAIN 
 
 ago, it is much, used in and about London, principally 
 at flour-mills, being considered a strong and safe 
 boiler, but smoky ; hence it is often used with Welsh 
 smokeless coal, but it is well adapted to Jukes' s, 
 Hall's, or other smokeless fire-feeding machines. I 
 consider that three, instead of two lower tubes, are 
 objectionable, as they are, in that case, too small to be 
 easily kept clean. Such boilers are not much used in 
 the manufacturing districts, where they are known as 
 " French " boilers ; but there are some good examples 
 in Lancashire, the two lower tubes being made large 
 enough for a man to get into to clean. They have 
 been commonly made by Messrs. B. Hick and Son of 
 Bolton, to go with their engines abroad. Some 
 erected by them at Barcelona, in Spain, were of well- 
 considered proportions, being 24 feet long, the main 
 body of the boiler 4 feet diameter, and egg-ended; 
 the two lower tubes each 2 feet 2 inches diameter 
 inside, with only two or three inches betwixt them ; 
 the vertical connecting pipes, or water-legs, were 
 18 inches diameter, and the fire-grate was 5 feet wide 
 by 6 feet long. 
 
 The most powerful boilers of this kind I have seen 
 were erected by the same makers, at the " India mill" 
 of Lees, Kershaw, and Co., in Stockport. They are 
 
AND IN STOCKPOET. 73 
 
 35 feet long by 5 feet diameter in the main barrel, 
 the 2 lower tubes are 2 feet 3 inches diameter, con- 
 necting pipes 16 inches diameter, and 2 feet 3 inches 
 high. The main barrel of the boiler is flat ended, 
 and contains a fire-flue 2 feet 3 inches diameter, 
 which is the most objectionable feature as regards 
 safety. Nevertheless, these boilers are worked very 
 satisfactorily with a pressure of 64 Ibs. per square 
 inch, and using little more than 40 tons of coal per 
 week. Two of them are capable of exerting about 
 500 indicated horse-power, driving cotton machinery, 
 &c. They consume about 3 Ibs. of coal per indi- 
 cated horse-power per hour, by means of a pair of 
 compound engines of 8 feet stroke, making 16^ strokes 
 per minute. One engine has the large cylinder 50 in. 
 diameter, and the small one of 23 in. The other 
 engine has the large cylinder of 52 in., and the small 
 one of 2 5 in. The steam is cut off at 5f ft. of the 
 stroke. These boilers occasionally work in conjunc- 
 tion with double-flued cylinder or Cornish boilers 
 6 feet diameter, with which they contrast very favour- 
 ably. The fire*bars are f -in. thick, and the rate of 
 combustion quick, say 10 to 15 Ibs. of common coal 
 per square foot per hour. The draught is produced 
 . by a brick chimney, 65 yards high by ,6| feet wide 
 
74 GREAT POWER, ECONOMY, AND 
 
 inside, at top, and 1 inch per yard batter outside. 
 The above data were collected in 1848-9, since which 
 the boilers have been supplied, I believe, with my 
 cleansing-machines, and with Dean's double fire- 
 feeding machines ; they have also been covered with 
 felt, &c. : all, of course, tending to produce a still 
 more economical result. I offer this as a sample, and 
 not by any means a solitary one, of the engineering 
 economy of Lancashire, which I would submit to the 
 consideration of my engineering friends in Cornwall, 
 with their lightly loaded engines and superior coal. 
 
 I scarcely need add, that none of the new smoke- 
 burning schemes have any share in producing the 
 economy at the India mill, unless Mr. Dean's excel- 
 lent fire-feeders be classed among such. They, how- 
 ever, do not operate by letting in cold air against the 
 boiler bottom, but by keeping it as hot as possible, 
 and the fire-door shut. At any rate, they cannot be 
 said to be benefited by anything that has come out 
 of Lord Pahnerston's Smoke Act. At another mill, 
 belonging to the same firm in Stockport, previous to 
 the erection of this one, having three large engines, 
 also, doing about 500 horse-power by 120 tons of 
 bad coal per week, several then well-known plans of 
 smoke- consuming, or prevention, were tried succes- 
 
SMALL COST OF ELEPHANT BOILERS. 75 
 
 sively without any appreciable saving of coal ; some of 
 them at an expense of some hundreds of pounds. The 
 list of inventors\or patentees' names, as given to me by 
 a member of the firm, comprised those of Rodda, the 
 two Halls, Chanter, Armstrong, and "Williams. My 
 own plan, in this selection, it is only proper to state, 
 was the only one that cost them nothing, being 
 a careful system of charging the fires at the back, 
 which I introduced at the same works, the Mersey 
 mills, then belonging to another firm, many years 
 previously. This mode of firing is described in one 
 of my " Tracts on Steam," also in the Artisan Club's 
 Treatise on the Steam Engine. 
 
 I might here ask what possible objection could be 
 raised against taking so simple and efficient a boiler 
 as above described, and of which the performance can 
 be so easily verified, and place it in an iron steamer, 
 at once, and withal at so cheap a rate, (from 35 to 
 40 per ton of Low Moor iron,) in place of the 
 present multitubular marine boiler, costing double 
 the expense ? 
 
 In referring to Arthur Woolf as the inventor of 
 boilers composed of systems of comparatively small 
 water-tubes, and which he was mainly conducive to 
 bring into use between 1810 and 1820, it is not to 
 
76 DEMAND FOR WOOL/S BOILERS. 
 
 be understood as applying exclusively to the parti- 
 cular form of boiler patented by him. That boiler 
 was, for reasons applicable to most patented articles, 
 not the best specimen of the invention, and it was 
 deficient in proper circulation of the water. Woolf s 
 boilers were really not successful until they took the 
 form of the Elephant, or French boiler, the latter 
 designation being applied in consequence of its being 
 first introduced, if not also first made, in France, by 
 Mr. Woolf himself. 
 
 I rather wish to consider him in common with 
 Oliver Evans in America and Dr. Alban on the Conti- 
 nent, as the propounder of a principle of construction 
 of perfectly safe boilers for very high pressure, that of 
 confining the pressure entirely within tubes of compa- 
 ratively small diameter. That system of construction 
 was almost a necessary concomitant of the intro- 
 duction of the compound high and low pressure 
 engines by Woolf and Edwards, which engines have 
 been, since their time, extensively made by Hall, 
 Humphreys, Eennie, Hick, and others. The great 
 -success of these engines m. extreme economy of fuel 
 with extreme high-pressure steam, has for some time 
 past created a demand for suitable boilers ; and that 
 4emand has been recently met, in an excellent form 
 
DUNN'S PATENT EETOET BOILEE. 
 
 77 
 
 of boiler partly on Woolf's principle by Dunn, Hat- 
 tersley, and Co., of Manchester. But in which, the 
 circulation of the water is more perfect than in Woolf 's 
 original plan. 
 
 The patent boiler of this firm, termed by them 
 " the Duplicate or Eetort boiler/' is represented in 
 the annexed cut. 
 
 FIG. i. 
 
 It was first introduced to public notice at a meet- 
 ing of the Institution of Mechanical Engineers at 
 Manchester, and has since been tested to work with 
 perfect safety at 250 Ibs. per square inch. One of 
 the retorts, 19 inches diameter having been purposely 
 
78 MUD COLLECTORS, WATER HEATERS, 
 
 pressed until it burst, was found to sustain the 
 extreme high pressure of 525 Ibs. before it gave way. 
 This boiler appears to be formed principally with a 
 view to portability and lightness, for convenient transit, 
 in which it certainly exceeds all others. Besides its 
 great strength, it has, in my. estimation, other valu- 
 able features, such as its capability of admitting any 
 modification in size of fire-grate, or of fire-feeding 
 machinery, underneath it ; and next .to that is the 
 very large proportion of effective heating surface 
 exposed to the direct radiation of the fire on the 
 grate. ,It has also the advantage of admitting of the 
 retorts 'being turned over, as they become blistered or 
 worn over the fire,, or of 'being replaced by others far- 
 ther off, or by nWo^es. 
 
 An attentive consideration' of Mr. Dunn's boiler 
 will discover it to possess some valuable peculiarities 
 in regard to the deposit of mud, which so long as the 
 water chambers are connected, must necessarily lodge 
 principally in a few of the retorts farthest from 
 the fire-grate. The retort at the extreme end will in 
 fact act as a mud vessel or cleaning apparatus for the 
 remainder. A most important purpose will thus be 
 effected, which I hope to have an early opportunity 
 of comparing with previous inventions for the same 
 
AND BOILEll CLEANERS. 79 
 
 purpose before pronouncing a decided opinion. Content 
 for the present in remarking that the same conditions 
 which constitute the last retort of the series an effi- 
 cient mud collector, also constitute it the most appro- 
 priate portion of the boiler at which to supply the feed 
 water, and thereby act as a heater to the latter. v To 
 this portion of the boiler Mr. Dunn attaches a cock, 
 or other means of blowing off the sediment frequently. 
 Of mud collectors and water heaters combined there 
 are a great many varieties, among which we may 
 mention that of Mr. E. Green, of Wakefield, as one 
 of the most successful in extensive use ; but I have 
 never seen any that in simplicity and compactness ap- 
 proaches this of Mr. Dunn's, and I would say it is 
 applicable to other boilers, the Cornish in particular, 
 as well as the retort boiler, of which it is a component 
 part. 
 
 Of cleaning machines that are applicable and effec- 
 tual in every situation, to all qualities of water, and 
 every kind of boiler, locomotive, stationary, and ma- 
 rine, there is only one variety ; that with the internal 
 collecting vessels, agitator, and blow-off cock, that can 
 prevent priming. And this they do most effectually 
 under all circumstances, if there be room in the 
 boilers to fix them. Nothing can be of greater import- 
 
80 GALLOWAY'S PATENT MARINE BOILER. 
 
 ance in improving the steam engine than the effectual 
 prevention of priming, and the snbject of cleaning 
 machines is on that account alone almost entitled to 
 some future volume of such a work as this to itself. 
 
 I was not aware until after page 33 of this work 
 was printed, that any of Messrs. Galloway's conical 
 tube boilers had been tried in sea-going vessels, but 
 learning the fact that some vessels had been re- 
 cently out to Constantinople containing them, I im- 
 mediately procured the above sketch from the patent 
 office, which I am informed represents correctly the 
 boilers in question, although not drawn to any precise 
 scale. 
 
81 
 
 CHAPTEE II. 
 
 SMOKE PREVENTION AND ITS FALLACIES. 
 
 WHILE the greatest attention has been given by 
 engineers at all times in advancing the steam engine 
 towards perfection, much less has been done than 
 ought to have been done in improving the construc- 
 tion of the boiler ; but least of all has been done for 
 the furnace the details of fire-grate, the supply of 
 fuel, and the most important of all, the management 
 of the FIEE, upon the proper operation of which much 
 of the efficiency of the machine is dependent. The 
 business of the "stoker," however subordinate and 
 apparently unimportant, cannot long be neglected 
 with impunity; for, like the organ-blower, he will 
 occasionally let us know that the instrument cannot 
 work without him. That portion of mechanical 
 engineering which concerns the architecture of fur- 
 naces, has been for so long a period left to the mercy of 
 the operative bricklayer and the ironfounder, who have 
 
82 ADVERTISING QUACKS AND 
 
 both done what they could with large quantities of 
 ire-brick, fire-clay, and thick heavy fire-bars, that it 
 has become, like certain less agreeable portions of 
 another profession we might name, which the re- 
 gular practitioner commonly endeavours to avoid, 
 but which there are plenty of " irregulars " ready to 
 occupy. The consequence of this has been, as in the 
 profession alluded to, that this important branch of 
 engineering is so much over-run by quacks and pre- 
 tenders, as generally to excite a considerable degree 
 of contempt in honourable minds for the section of 
 the arts thus degraded. To these phenomena may now 
 be added the natural effect of the recent alteration in 
 the patent law, which has so suddenly overwhelmed 
 the community with swarms of great and little mono- 
 polists in every direction, and it is not the least part 
 of the swarm which has settled down upon that oppro- 
 brium of engineering, the smoke nuisance. On this 
 subject every smatterer on science has a theory of 
 his own to uphold. Nearly every ironmonger is now 
 a patent-furnace monger, and any gas-fitter is ready 
 to fit us with his patent apparatus for "consuming 
 smoke." Advertising quacks, whose business is 
 puffing, are ready to subdue smoke puffs, and promise 
 at the rate of 20, 30, and 40, or any other per 
 
THEIR FALLACIOUS PROMISES. 83 
 
 centage, in saving of fuel, by adopting their several 
 nostrums, each guaranteed by hundreds of cut-aiid- 
 dried testimonials. Audacity in this matter is far 
 from being confined to the needy pretender, but 
 stands out boldly bedizened in the canonicals of 
 science. The style adopted, and the expedients 
 resorted to by these smoke doctors, are worthy of 
 Dr. Solomon, of Balm of Gilead notoriety, or of any 
 other of that band of patriots who request us to 
 beware of counterfeits. The policy pursued is that of 
 continual reiteration to induce a belief of incredible 
 statements, or to create faith in such respectability as 
 at least possession of money may give. This we see 
 daily in glaring signboard announcements. Indeed 
 some of the most conspicuous and wealthy of those 
 worthies are known to have competed at public meet- 
 ings in the provinces, in extravagance of pretension, 
 bidding against each other for public favour, by pro- 
 mising a saving of 50 and 60 per cent! ! Of the honesty 
 or dishonesty of such representations, it is needless to 
 speak ; but I must state emphatically that, having 
 closely attended to every experiment of consequence 
 in smoke burning for a series of years, I have never 
 yet found evidence of a saving of even 5 per cent, by 
 any plan of preventing or consuming smoke, however 
 
34 NO SAVING IN FUEL 
 
 "perfect" And, further, I have found the more 
 perfect the consumption was of smoke, the less was 
 the saving of fuel ; or, more properly speaking, a 
 greater consumption of fuel is required in raising a 
 maximum quantity of steam from the same boiler in 
 the same time, when the smoke is entirely prevented, 
 than is the case when smoke prevention is not at- 
 tempted at all. In short, perfect combustion is not 
 perfect economy in practice, but far from it. 
 
 That I have long been convinced of the futility of 
 smoke-consuming furnaces as a measure of economy, 
 although I have had, and have still, the strongest 
 inducements of self-interest to endeavour to think 
 otherwise, will be evident, if I transcribe a passage from 
 a work published by me nearly twenty years ago, parts 
 of which had been some years previously drawn up in 
 the shape of reports at the request of various cotton, 
 and other manufacturers, in Lancashire. This work 
 was printed by desire of those gentlemen in 1837, and 
 a second edition was published in Manchester in 
 1838;* and as it has long been out of print, and as 
 it still expresses my views upon this subject, I 
 
 * A Practical Essay on Steam Engine Boilers, as now 
 used in the manufacturing district around Manchester. 
 By Robert Armstrong, C. E. 
 
BY SMOKE-BURNING. 85 
 
 believe that no apology is necessary for the introduc- 
 tion of the following quotation: 
 
 " In nothing has the philosophical manufacturer or 
 amateur mechanic been so much at variance with facts, 
 and the experience of practical men, as on the subject 
 of smoke-burning. It is perfectly true that the black 
 carbonaceous matter, which usually escapes along 
 with the incombustible gases, and which is the only 
 visible constituent of what we term smoke, is all so 
 much fuel; and when properly consumed under the 
 boiler is undoubtedly a saving of coal ; but it unfor- 
 tunately happens that the saving is so inappreciably 
 small that none who have tried it fairly have been able 
 to calculate exactly its amount, except when it has 
 taken the negative form, which it has most frequently. 
 It is not my intention to speak disrespectfully of any 
 of those who have proposed to save fuel by burning, 
 or 'consuming smoJce by combustion,' as they usually 
 prefer to term it, for they have generally, if not 
 universally, deceived themselves before they led others 
 astray, as the hundreds of patents for that purpose, 
 and the hundreds of thousands of pounds expended 
 
86 LOSH'S DOUBLE-FURNACE 
 
 over them, amply testify. Patent inventors, indeed, 
 of improved furnaces for ' saving fuel by consuming 
 smoke ' deserve no small share of public gratitude, 
 from the many opportunities they have given us of 
 ascertaining by experiment a great number of prac- 
 tical data, and useful results, which are now available 
 for other more important improvements." 
 
 The pursuit of "smoke-burning," in fact, has been 
 the philosopher's stone of the present century. Specu- 
 lative and practical chemists of the brightest intellects 
 have dabbled in it; such men as Eumford, "Watt, 
 Dalton, and Henry were believers in its economy. I 
 cannot speak as to Davy, but it is thought that the 
 predilections of the great living German chemist, 
 who has done so much for the brewing trade of 
 England, lie that way ; at least his foremost disciples 
 in this country hold to the yet popular doctrine that 
 sixty or seventy per cent, of the fuel is to be saved by 
 burning the invisible carbonic oxide gas, which now 
 escapes from our iron furnaces in Staffordshire. 
 
 On this subject I can speak with the more confi- 
 dence from having had a good deal of practice in 
 directing the application of various patent, and other 
 apparatus and methods, devised to enable furnaces to 
 consume their own smoke in different parts of this 
 
WITH ALTERNATE FIRING. 87 
 
 country, as well as in the planning and erection of 
 boilers and furnaces generally in the ordinary way. 
 Up to the passing of Michael Angelo Taylor's act, 
 nearly thirty years ago, which made smoke-prevention 
 in some measure compulsory, little or nothing had 
 been done in the North of England except on the 
 double furnace system of Mr. Losh, of Newcastle-on- 
 Tyne, patented in 1815. It was more successful 
 with chemical stoves, salt pans, and slip kilns in 
 potteries, than with engine boilers. When applied 
 to the latter, it was objected to on the ground that 
 it required a larger boiler to do the same work, as well 
 as two fires to do the work of one. I endeavoured to 
 introduce it into Lancashire in 1827, but did not 
 succeed until some years after the patent had expired, 
 when the above objection was found to be untenable. 
 The large boiler proved to be a great advantage, and 
 alternate firing was very economical, independent of its 
 convenience for consuming smoke. My mode of 
 applying it was to place simply a wall of fire-brick 
 longitudinally upon the fire-grate, nearly the whole 
 length from the bridge to the dead plate ; but so that 
 both sides could be charged through one fire-door. 
 This method was used in Manchester in a boiler, em- 
 ployed to drive a40-horse engine, at the Store Street 
 
88 DIVIDED FIRE GRATES 
 
 Cotton Mill, belonging to Mr. Win. Jones. And 
 I afterwards erected similar divided furnaces at the 
 Worsley Flour Mills, belonging to the Earl of Elles- 
 mere, and at several other places, with some improve- 
 ments, which consisted mainly in restricting the mid* 
 feather wall to one-half the length of the grate, and 
 making the fire-bars at the front of the grate thinner, 
 and with wider spaces, than at the back. The air 
 was generally let in through the sides of the furnace at 
 about half the length of the grate ; but at Mr. Jones's, 
 where there was a good chimney, it was admitted by 
 setting the fire-door ajar 1^ to 2 inches, for 2 or 3 
 minutes after each firing. In cases where the chim- 
 ney was low, or had a bad draught from other causes, 
 the supplementary air was forced in over the fire by 
 means of a small rotary fan; and where convenient, 
 this air was in a highly heated state, say at 400 or 
 500 degrees. In this manner, this species of furnace 
 was worked at the above Mour Mill, continuously 
 with great satisfaction and economy, driving a com- 
 mon low pressure engine working six pairs of 4 feet 
 stones, and other machinery, with about 6 Ibs. of 
 inferior coal per indicated horse power per hour. The 
 proportion of the power required by the blowing fan 
 was only about half a horse power. To show the 
 
WITH FAN DRAUGHT. 89 
 
 great advantage of either a good draft, or artificial 
 blast, in all cases of smoke-consumption, it is proper 
 to state here that Williams's patent system was 
 previously tried at the same boiler with the same 
 fire-grate area, without enabling the engine to work 
 half the above load ; while the same system applied 
 by the same parties to another, small engine on the 
 same estate, with a very lofty chimney, was moderately 
 successful. 
 
 The smoke from the chimney of Worsley Mill, 
 when in full work, was perfectly invisible, with the 
 exception of a slight vapour during the time that the 
 fire-door was allowed to remain open, but no longer. 
 
 The situation of this flour-mill, a picturesque spot, 
 about half a mile in front of Worsley Hall, was 
 such that the mill was nearly hidden from view at 
 that mansion, and its existence would have been 
 unobserved except for the smoke which rose above 
 the trees, before the improvement was applied. , When 
 the smoke was prevented, the circumstance accident- 
 ally coming to the knowledge of the Earl of Carlisle, 
 when on a visit at Worsley, he took the opportunity 
 of convincing himself of the facts as above related, 
 and on their being reported to the Earl of Ellen- 
 borough, then first Lord of the Admiralty, that 
 
90 DIVIDED FIRE-GRATES AT CHATHAM 
 
 nobleman at once ordered a similar apparatus to be 
 erected at Chatham Dock-yard. The apparatus was 
 accordingly applied by me to two 20 -horse boilers at 
 the Lead mill there, for which purpose I planned the 
 urnaces as nearly as possible a copy of those at Wors- 
 ley, and the results were very nearly the same. The 
 chimney stood right opposite the windows of one of 
 the royal hospitals, to which the smoke had previ- 
 ously been -a great nuisance; but, after six months' 
 trial of the new plan, the chief physician of that 
 establishment reported to the Admiralty the entire 
 removal of the nuisance, and that the health of the 
 inmates had been greatly improved in consequence. 
 This Eeport was published in the " Health of Towns 
 Gazette," in 1849. And, as I have just been in- 
 formed by the Superintending Engineer of the Dock- 
 yard, the apparatus has continued to work unin- 
 terruptedly to the present time, (1856,) with uniform 
 success."* 
 
 * In 1839, 1 introduced the double furnace system into a 
 steamer, " the William Fawcett," belonging to the Penin- 
 sular Steam Company, and she continued to ply with the 
 furnaces thus altered until new boilers were, I believe," intro- 
 duced a considerable time afterwards. The arrangement of 
 these furnaces differed somewhat from Losh's plan. Each. 
 
AND AT WOOLWICH ARSENAL. 91 
 
 About the same time several other double or divided 
 fire-grate furnaces were erected, by other parties, at 
 the cotton works of Mr. John Paley, and at other 
 places, in Preston. These were more nearly on Mr. 
 Lostfs original principle, having two separate fire- 
 doors and two ash-pits. 
 
 Mr. Howard, Mr. Thomas Hall, and a great num- 
 ber of other parties, have introduced various modifi- 
 cations of double furnaces since the date of Mr. 
 Losh's patent, and more or less successfully. The 
 last modification of the kind I have seen, was erected 
 at a small boiler in the Eoyal Arsenal, Woolwich, by 
 Messrs. Abernethy and Co., Engineers, of Aberdeen, 
 in 1856. The peculiarity of this plan consists in a 
 
 furnace had a damper behind the bridge, which could be 
 shut when required, and the smoke produced in that fur- 
 nace had then to descend through a suitable passage, into 
 the ash-pit of the adjoining furnace, which, by this time, 
 had burned bright, and ascending through the fire, mixing 
 with atmospheric air, it was completely consumed. To 
 maintain the necessary draught an exhausting fan was 
 applied to the chimney. I simultaneously introduced other 
 improvements which very much lessened the consumption 
 of steam, so that, although the boiler was less powerful than 
 before, it was still equal to its work as smaller demands were 
 made upon it. J. B. 
 
92 SMOKE-PREVENTING FUENACES 
 
 jet of fresh air from a pipe on each side of the fur- 
 nace being admitted alternately, to correspond with 
 the alternate firings by which the smoke from the 
 newly fired furnace is driven laterally, or horizontally, 
 against the bright fire and flame of the other. This 
 is the principle of admitting air patented by Mr. 
 Spibey of Nottingham, several years ago, and exten- 
 sively applied by him to single furnaces ; and by this 
 mode of procedure the injury to boiler bottoms from 
 cold air rising upwards against them, at or beyond 
 the bridge, is likely to be avoided. I pass over a 
 great many other plans of double fires, such as Gallo- 
 way's, Bose's, Fairbairn's, Ormrod's, HicFs, Bristow 
 and Atwood's, and others, as the principle of the 
 whole is nearly the same, and it would occupy too 
 much space to enter into the details. 
 
 After Mr. Losh's double furnace principle, the next 
 smokeless furnaces that came into public favour 
 were those of Wakefield, Parkes, Brunton, and Stan- 
 ley. The two latter being accompanied by, or mainly 
 consisting of, fire-feeding machinery, which was neces- 
 sarily expensive, came slowly into use, but they were 
 both perfectly well established previous to the year 
 1827 ; and the only reason they are not now 
 more frequently met with is, that they are not 
 
BY BRUNTON AND STANLEY. 93 
 
 well adapted to boilers with internal furnaces. The 
 two former plans, consisting principally of alterations 
 in the brickwork, came more rapidly into use in Lan- 
 cashire. The smoke-consuming furnaces of Mr. John 
 Wakefield, I believe, had the precedence of the other 
 in point of time, as I had some pulled down 
 which had been erected by him at the cotton-mill 
 of Messrs. Clogg and Norris, in Long Millgate, 
 previous to 1818, and which I re-constructed with my 
 own improvements in 1830. About the same time, 
 several were taken down at Thos. Hoyle and Sons' 
 print-works, Mayfield, and other places, which had 
 been a much longer time in use. In fact, Mr. Wake- 
 field used to complain to me how Mr. Parkes, " hav- 
 ing come after him, stole his ideas " of the split 
 bridge, and air-valve at the back of the ash-pit. 
 However this might be, it is certain that Parkes's 
 system became by far the most popular; a great 
 number of furnaces being erected by him all over the 
 country, from 1820 to 1825, after which they were 
 erected by him extensively in Prance. In the mean 
 time, however, though the plans of Wakefield and 
 Parkes were originally similar, they soon grew widely 
 different. Wakefield persevered with thin and fre- 
 , quent firing, thin and scientifically constructed fire- 
 
94 SMOKE-BURNING FURNACES 
 
 bars, well-arranged tools, perforated fire-bricks, for 
 heating and diffusing the air, like Williams, and 
 pigeon-hole bridges ; he also paid very great atten- 
 tion to the fireman's art, and he only failed, as he 
 said, from want of it at last. On the other hand, 
 Parkes's system was carried on by him to the 
 extent of enlarging and deepening the furnaces, so 
 as to hold upwards of a ton of coal at a time. This 
 quantity was usually introduced into the furnace 
 during the first two hours in a morning, beginning 
 rather thin near the bridge, and, as it became ignited, 
 gradually increasing the thickness of the charge until 
 within 2 feet of the fire door, where the coal was filled 
 quite up to the boiler bottom. When arrived at this 
 stage, the combustion was entirely that of the gas 
 from, the raw coal. The surface of the fire then 
 formed an inclined plane towards the bridge, and as 
 the supply of air through the bars was thus cut off, 
 the combustion was kept up entirely by the air 
 through the air-valve at the back of the ash-pit, and 
 the split bridge, which last was much wider than 
 Wakefield made it, being commonly 3 or 4 inches, or 
 more. During the first three or four hours of the 
 day, the air-valve was gradually closed by the fire- 
 man, by which time the diminished quantity of fuel 
 
BY WAKEFIELD AND PAJtKES. 95 
 
 in front of the bridge allowed sufficient air to pass 
 through in that way. The air- valve was then shut up, 
 and not opened again during the day. The proper 
 action of the fire was, after this, entirely dependent 
 upon the proper management of the dampers, and in 
 the middle of the day the steam was regulated by the 
 admission of less or more feed- water to the boilers. 
 
 The above is a programme of the mode of proceed- 
 ing with Parkes's system at the cotton works of Mr. 
 John Pooley of Hulme, where I had most experience 
 with it, thirty years ago ; and it is very nearly the same 
 as the mode carried out at the works of Messrs. Hor- 
 rockses Miller and Co., of Preston, up to within the 
 last few years. 
 
 There is no doubt that considerable economy was 
 obtained by this plan, when very carefully managed, 
 with very low pressure steam and very large boilers, 
 even to the extent of getting an evaporation of 7 to 
 8 Ibs. of water to 1 Ib. of Lancashire coal ; but it was 
 too unwieldy and cumbrous a system to continue in 
 use more than a few years, excepting at the last men- 
 tioned place, where special provisions were made to 
 suit it. 
 
 It is not my business, however, in tin's place, to 
 ' write the past history of smoke-burning, so much as 
 
 * 
 
96 A NEW SMOKELESS FIRE-GRATE. 
 
 to describe what is doing at the present time in that 
 direction. With this view, I here insert a brief 
 description of a new form of fire-bar and furnace- 
 grate which I have had in operation for some time 
 past, at different places with very satisfactory results ; 
 and I expect to be able to present a more detailed 
 account of the arrangements, accompanied by proper 
 drawings of this and other plans of recent construc- 
 tion, in Mr. Bourne's forthcoming work on the Steam 
 Engine. 
 
 UNIVERSAL "ARGAND" FIRE-GRATE. 
 
 Like all other furnaces which burn, prevent, or con- 
 sume their own smoke by an improved combustion 
 of the gaseous portion of the fuel, the principle of 
 this one depends on the admission of a sufficient 
 quantity of fresh air to the smoky flame of bitumi- 
 nous coal, as well as to the carbonic-oxide gas pro- 
 duced by a thick fire of coke or from Welsh coal or 
 other non-bituminous fuel; but it differs from all 
 others in the place of such admission. I do not admit 
 this fresh air at the bridge, although, by that mode, 
 the disappearance of the smoke is usually the most 
 perfect, because, when so admitted, it operates as a se- 
 rious check to the draught, and lessens the power of 
 
NEW SMOKELESS FTJBNACE. 97 
 
 tlie furnace. Neither is the air admitted at or about the 
 fire-door, because, when so admitted, it has a tendency 
 to be drawn between the fire and the bottom of the 
 boiler, thereby cooling a larger portion of the fur- 
 nace, and diminishing the economy of the fuel. The 
 necessary supply of fresh air to the interior of the 
 furnace is admitted, in this furnace, at an interme- 
 diate position between the fire-door and bridge; 
 or, in fact, it is admitted between the front end and 
 the middle of the fire-grate. 
 
 This inlet aperture for the air I make through a 
 hollow, or double bearing-bar between the first and 
 second of two or more lengths of fire-bars, and being 
 thus surrounded on all sides by the fire and flame, as in 
 the Argand lamp, it might be called the " Argand Fire- 
 grate," or furnace. (See Frontispiece.} 
 
 The constituent bars of each series of fire-bars are 
 of different thicknesses, the thickest being placed at 
 the back for slow, and the thinnest in front for quick, 
 or ordinary combustion, the thin bars having also the 
 widest spaces between them. 
 
 In supplying this furnace with bituminous coal, it 
 must be charged thick on the back of the grate, until 
 the coal reaches nearly, or quite, up to the top of the 
 bridge, gradually sloping forward to the margin of 
 
98 NEW SMOKELESS FURNACE. 
 
 the air-space ; while on the thin or front bars,, only, 
 it is fired in the ordinary way. 
 
 No complicated apparatus of any kind is required 
 to be attended to, and no additional tools are wanted 
 beyond a " slice " with a blade a foot long, bent flat- 
 ways at right angles, for clearing away obstructions 
 in the air-space. For greater facility in doing this, a 
 modification of the old-fashioned " stoking-bar " is 
 sometimes placed across the ash-pit exactly under the 
 double bearing-bar, but made in the form of a flat 
 plate, and with a raised ledge to serve as a guide to 
 the tool.* No great degree of care is requisite for 
 preventing smoke in this furnace. It is only neces- 
 sary to throw the coal boldly in, principally towards 
 the further end of the grate, as a man would fill a 
 cart or a barrow, and plenty of it, closing the fire- 
 door in as short a time as possible, and the smoke 
 will be found to be no darker than from a common 
 house fire, provided the air-space be opened occasion- 
 ally with the slice above mentioned. If the chimney 
 
 * My improved picker-bar or " stoking plate" above 
 mentioned is in the case of a bad draught made to turn on 
 gudgeons at the sides of the ash pit by means of a bell 
 crank and rod, so as to' check or regulate the influx of air 
 through the double bearing bar if at any time required, 
 
IMPORTANCE OF SURPLUS DRAUGHT. 99 
 
 be sufficiently large, which is by far the most impor- 
 tant condition, the smoke may thus be made nearly 
 transparent, and, if desirable, can be rendered entirely 
 so, by putting a little damp coal on the front part of 
 the fire, and taking pains to clear out the air-space 
 after each firing. 
 
 The above is a recipe for constructing a smokeless 
 steam engine furnace, than which it is perhaps impos- 
 sible to imagine a cheaper or simpler arrangement. 
 But it is necessary again to caution those who would 
 adopt it, or any other plan of smoke-prevention by 
 hand firing, that the total area of fire-grate should 
 be at the same time increased by 20 or 30 per cent, 
 beyond what is usually considered necessary with the 
 common smoky furnace, and ordinary stoking. And 
 besides this, there must be always a surplus of chim- 
 ney power at command, by means of the usual coun- 
 ter-balance weight to the damper, suspended in the 
 stokehole within easy reach of the fireman's hand, 
 while engaged in charging the furnace. Without 
 those two provisions, especially the first, times will oc- 
 cur in the case of sudden demands of an engine with a 
 variable load, for steam, when the influx of air must 
 be controlled ; otherwise the engine may go slow or 
 stop, and smoke of greater or less opacity will at such 
 
100 WANT OF DRAUGHT A CAUSE OF SMOKE. 
 
 times issue. In the event of the engine going slow 
 from the above, or any other temporary cause, just 
 after a charge of coal has been put into the furnace ; 
 then it is that the fireman finds a resort to the damper 
 most valuable. When the draught is strong, a slight 
 touch of the damper so as to increase the escaping 
 area will commonly be sufficient to prevent the engine 
 from stopping, or will enable it to recover its speed. 
 In order to estimate the value of a large fire-grate 
 area and surplus draught, it is only necessary to con- 
 sider what would be the effect under the same circum- 
 stances, with a confined fire-grate, and the damper 
 already wide open: there is then of course no resource 
 left but stirring the fire, and consequently stirring up 
 a smoke at the same time.* 
 
 * A quick draught is in one respect tantamount to a large 
 fire-grate area, since it equally enables more coal to be 
 burned in a given time, and thus increases the power of 
 the boiler in generating steam. A quick draught, however, 
 has this further advantage, that inasmuch as the temperature 
 of the furnace is higher when the same quantity of heat is 
 generated in a small space than what it will be when gene- 
 rated in a large space, the heat is transmitted much more 
 rapidly to the water of the boiler in the case of the strong 
 draught by reason of the higher temperature in that case 
 obtaining. As therefore there is more heat transmitted in 
 
INJURY FROM ADMISSION OF COLD AIR. 101 
 
 Having shown how easy it is, with a proper arrange- 
 ment of the furnace bars, to avoid smoke, it will be 
 useful to show how, with improper arrangements, it 
 is also very easy to do a great deal of harm to the 
 boilers, however perfectly the smoke may be consumed 
 or prevented. 
 
 That injury to boilers, and danger from explosions, 
 is to be apprehended from any system of preventing 
 smoke, in which a current of cold air is directed 
 against the boiler bottom, is no longer a mere opinion, 
 but a fact which cannot be gainsaid. This will appear 
 sufficiently plain to any one who will attentively 
 read the following copy of a Report of an examination 
 I made of a case of the kind in Manchester several 
 years ago. 
 
 the region of the furnace, in the case of the strong draught, 
 there will be less remaining to be transmitted in the region 
 of the flues. In other words the flues will have less work 
 to do, and they may either be made shorter, or the heat 
 will be more thoroughly absorbed. J. B. 
 
102 INJURY PRODUCED BY WILLIAMS 7 S PATENT. 
 
 COPY OF EEPOET 
 
 ON WILLIAMS'S PATENT SMOKE-BUENING FURNACE. 
 
 u TO MESSRS. HAMNETT AND CO., CALENDERERS, WATLING 
 STREET, MANCHESTER. 
 
 GENTLEMEN, In accordance with your request, I 
 have carefully examined into the circumstances attend- 
 ing the injury sustained by your steam engine boiler, 
 during the three days 7 trial of Mr. Williams 7 s patent 
 smoke-consuming furnace, and have to report thereon 
 as follows : 
 
 Some of the plates in the boiler bottom behind the 
 bridge appear to have been exposed to a considerable 
 degree of expansion and contraction alternately, arising 
 from frequent alternations of temperature, by which 
 means the rivets have been dragged successively in 
 opposite directions, until they have become loosened 
 in the rivet holes, and the boiler has become leaky."* 
 
 One plate is also what is usually called "burnt out/ 7 
 which is what generally happens when one side of an iron 
 plate is frequently and suddenly heated and cooled, while 
 
 * See illustrations of similar effects in figures 5 and 7, 
 chap. iii. of this work. 
 
REPORT TO HAMNETT AND CO. 103 
 
 the other side, from its contact with the water in the 
 boiler, is kept at a moderately uniform temperature. 
 In this case, also, owing to the necessarily laminated 
 structure of wrought iron, combined with the heating 
 and cooling process above described, " a blister " has 
 arisen in one of the plates, and this blister has been 
 the immediate cause of the giving way of the boiler, 
 by so far weakening it as to allow the pressure of the 
 steam and water to force down the plate in that parti- 
 cular place. 
 
 The main cause of the above results is clearly to be 
 traced to the imperfect construction of the furnace, 
 inasmuch as the passage for the admission of fresh air 
 to the flame behind the bridge, is unprovided with a 
 valve or other means of regulating the quantity of air 
 so admitted, or the time of its admission, within the 
 reach of the engineer whilst engaged in firing the 
 boiler. 
 
 To enable me to explain this point more fully to 
 your satisfaction, I may state that this mode of pre- 
 venting, or (as it is most commonly called) "burning" 
 the smoke, by admitting atmospheric air at or behind 
 the bridge of the furnace, has been long known, and 
 frequently practised in Manchester since it was first 
 generally introduced here by Mr. John Wakefield 
 
104 REPORT TO HAMNETT AND CO. 
 
 more than twenty years ago. This gentleman also 
 practised the method of diffusing the air through 
 several small apertures inside the furnace chamber, in 
 the same manner as Mr. Williams. But in all Mr. 
 Wakefield's furnaces, as well as those of Mr. Parkes, 
 that I ever saw, the passage through which the air 
 was allowed to communicate with those apertures was 
 supplied with a regulating valve for the purpose of 
 admitting the proper quantity of air, suitable to the 
 varying state of the fire, or to shut it off at the dis- 
 cretion of the engineer or fireman. And the uniform 
 practice of all operative engineers has always been, 
 when no flame was passing from the fire, and conse- 
 quently no smoke being made, to shut the air off 
 entirely. 
 
 In your case, however, the furnace is so arranged 
 that a constant stream of cold air is uniformly rush- 
 ing into the main furnace chamber or flame-bed of the 
 boiler at all times, and whether there is a flame passing 
 over the bridge or not.* 
 
 * I am aware that the production of the invisible carbonic 
 oxide gas, from a thick coked fire, may sometimes create a 
 demand for air when no black smoke is passing. But I con- 
 tend that such air should be supplied through the grate, and 
 not behind the bridge, unless carefully regulated. 
 
REPORT TO HAMNETT AND CO. 105 
 
 The certain and inevitable consequences of this state 
 of things are, that every time the fresh coal is thrown 
 on the fire, and a flame is produced sufficient to reach 
 through the throat of the furnace, the current of fresh 
 air passing directly into [or against] the flame from below, 
 drives the latter right up against the boiler bottom in 
 the manner of a blow-pipe, causing it to impinge with 
 peculiar intensity against that portion of the boiler bot- 
 tom immediately exposed in the direction of the blast. 
 On the other hand, as soon as the fire on the grate 
 has burned bright, and the flame does not extend over 
 
 Hyper criticism might contend that, instead of a " stream 
 of cold air," it would have been more correct to say streams 
 of cold air, inasmuch as the air was supplied through a 
 perforated plate between two bridges, which did not form, 
 strictly speaking, the split or double bridge of Parkes, being 
 much wider apart. These numerous streams, however, 
 united and became one stream after passing through the 
 meshes of the "Patent Riddle," which riddle grating or 
 perforated plate formed the special claim of the patent, and 
 could be of no earthly use, unless indeed it had been used 
 for heating the air. That purpose; however, was especially 
 disclaimed in the patent, and the air, in this particular case, 
 was brought in a separate channel at a distance from the 
 boiler intentionally that it might be cold, and that all access 
 .to it by the engineer might be cut off. 
 
106 REPORT TO HAMNETT AND CO. 
 
 the bridge, the COLD air striking against the same part 
 of the boiler bottom, which had just before been 
 so unduly expanded by intense heat, a sudden contrac- 
 tion of the metal necessarily ensues, besides a great 
 waste of fuel, and difficulty in keeping up the steam. 
 
 I have long paid great attention to the operation of 
 smoke-burning furnaces generally, and more particu- 
 larly to those constructed on the principle so imper- 
 fectly attempted by Mr. Williams, that is, by supply- 
 ing to the carbonaceous products evolved, their full 
 saturating equivalents of oxygen for effecting the most 
 perfectly attainable combustion of their elements, and 
 thereby preventing smoke, but which can only be 
 safely effected by carefully regulating the admission of 
 air to the flame, for which, in Mr. Williams' s plan, 
 there is no provision made whatever. I have no hesi- 
 tation in stating that the result of my experience is, a 
 confirmed opinion against the economy of the process ; 
 being convinced, that, in ordinary circumstances, 
 there is more fuel wasted by the admission of cold air 
 to the boiler bottom, than is saved by the most per- 
 fect consumption of the smoke. This conviction has 
 been forced upon me by a careful and unprejudiced 
 examination of a great many steam engine furnaces 
 erected both by myself and others, including several 
 constructed by Mr. Williams himself. 
 
REPORT TO HAMNETT AND CO. 107 
 
 I may take the liberty of concluding this report 
 with a caution which I have been in the habit of 
 giving verbally to all those who have occasionally 
 consulted me on this subject for some years past. It 
 is that I have reason to believe that many extensively 
 fatal explosions of steam boilers, not otherwise satis- 
 factorily accounted for, have arisen from similar 
 causes to those detailed above, namely frequent and 
 sudden alternations of temperature at the lower part 
 of the boiler, inducing a tendency to burst downwards, 
 of which instances are constantly occurring. In fact, 
 in the case of your own boiler, the minor explosion it 
 has experienced, may be considered in the light of a 
 very narrow escape, for if the blistered plate had been 
 of rather a better quality of iron, so as to have held 
 out a few days longer, or until one or two of the 
 adjoining already injured plates had become nearly as 
 weak as itself, in all probability they would have given 
 way simultaneously, and produced an extensive explo- 
 sion, the effect of winch is usually, by reaction, to 
 force the boiler upwards, sometimes to a considerable 
 height through the supervening buildings, in a way 
 that has too frequently created an enormous destruc- 
 tion of life and property. 
 
 EGBERT ARMSTRONG. 
 
108 CONTROVERSIES OF RIVAL PATENTEES. 
 
 The reason for giving, perhaps, undue prominence 
 to the above letter or report, is that it was not origi- 
 nally published by me, that is, if printing and giving 
 away a large number of copies may be considered as 
 such but by Mr. Joseph Williams, of Liverpool, 
 then (in 1841), as now, well known as the proprie- 
 tor of the patent smoke-burning furnace of his brother- 
 in-law Mr. Kurtz, a scientific chemist of considerable 
 eminence. The letter itself was properly a private 
 business one, which, with other evidence, was, after 
 revisal by me, put into the hands of the solicitor 
 of the firm of Hamnett & Co. for legal purposes. 
 Although not then called on to justify the publication, 
 I did not object to it, because Mr. Joseph Williams 
 represented to me the injury his character and that of 
 his patent, which was for the use of hot air, might 
 sustain in being confounded with those of Mr. Charles 
 Wye Williams, whose patent was for the use of cold 
 air, owing to both persons having the same surname.* 
 Consequently many thousand copies of the report 
 were printed and circulated by Mr. Joseph, setting 
 
 * It is remarkable that four different persons of the name 
 of Williams, Irish, English, Scotch, and, I believe, Welsh 
 were the holders of smoke patents during the same year. 
 The first and second of whom only we now refer to. 
 
CONTROVERSIES OF RIVAL PATENTEES. 109 
 
 forth the distinctive appellations of himself and Mr. 
 Charles Wye at full length. This procedure was also 
 followed by Mr. John Chanter of London, the proprie- 
 tor of numerous smoke patents, publishing the same 
 thing. The object of both those gentlemen was pro- 
 bably the same, that of demolishing the business of a 
 rival patentee, which, there is no doubt, they did most 
 effectually; raising, at the same time, some rather 
 undignified discussions in the public press on their 
 various claims to notoriety in saving 30, 40, and 50 
 per cent, in fuel. In those discussions, except in self- 
 defence, I took no part, having no pecuniary interest 
 in any smoke patent, nor any sympathy whatever 
 with any of the combatants. 
 
 So effectually had all public interest died out in the 
 above discussion, which was supposed, as usual, by 
 many to be settled in favour of those who care to have 
 the last word, that I did not think it necessary to 
 allude to the subject in my " Rudimentary Treatise 
 on Steam Boilers," in 1851. The subject how- 
 ever, has been revived by the Society of Arts awarding 
 one of its prize-medals for an essay on smoke-pre- 
 vention, among others, to Mr. C. Wye "Williams, who 
 must have convinced the society that, "though 
 beaten, he can argue still." In this prize-essay Mr. 
 
110 ITERATION OF ME. C. W. WILLIAMS. 
 
 Williams has endeavoured to revenge his former 
 discomfiture by an onslaught on the whole of the 
 present generation of patent smoke-burners, which I 
 do not notice, but for the unfair use he makes of the 
 above report misquoting, garbling, and perverting 
 it in every possible way.* Hence the obligation 
 I am under in giving my report at full length as 
 above. 
 
 Considering that, although I stand sufficiently ab- 
 solved from the necessity of noticing Mr. Williams 
 any farther, there are one or two others whose prac- 
 tical abilities as engineers the public hold in high 
 respect, who have been led astray in this matter of 
 smoke-prevention, but who can have no interest or 
 desire, except to be set right as to facts. I think 
 it proper here to narrate the results of some experi- 
 ments I cotf2ucea upon smoke-burning in 1843, 
 with the view of illustrating some of the points then 
 under controversy. This information is afforded in 
 the following memorandum : 
 
 * See Ms letter on the smoke nuisance in the Engineer 
 newspaper, for May 30th, 1856. 
 
EXPERIMENTS ON SMOKE -BURNING. Ill 
 
 ACCOUNT OF EXPERIMENTS CONDUCTED AT THE COTTON 
 FACTORY OF THOMAS HOULDSWORTH, ESQ., M.P., IN 
 MANCHESTER, IN 1843, IN ORDER TO DECIDE ON 
 THE ECONOMY OF SMOKE-PREVENTION. 
 
 It will be remembered that a select committee of 
 the House of Commons was appointed to investigate 
 the smoke nuisance question in 1843, the results of 
 which investigation were published in a blue book 
 about the end of that year ; and on the evidence con- 
 tained in that and other reports, Parliament afterwards 
 proceeded to pass several new laws on the subject a 
 very proper thing in itself, if founded upon truth in- 
 stead of the most erroneous statements to the eifect 
 that manufacturers would be greatly benefited by the 
 measure in the saving of fuel thereby ensured. 
 
 Among other questionable evidence, by much less 
 reputable parties, published in this blue book, was a 
 statement by Mr. H. Houldsworth, supported by a 
 long array of tables and diagrams, asserting that, 
 " by an admission of air to the extent required to pre- 
 vent smoke," into the " body " of a steam-boiler fur- 
 nace, "much additional heat is produced, more 
 steam raised from the same weight of coals, and more 
 water evaporated in the same time." Particulars of 
 
112 
 
 EXPERIMENTS ON SMOKE-BURNING. 
 
 four experiments are detailed in order to show that 
 a gain of 35 and 36 per cent, was "made by admit- 
 ting air partly at the door, and partly at the bridge, 
 through one of Mr. C. W. Williams' s diffusion- 
 boxes/' (or patent perforated plates.) In the ap- 
 pendix to the report it is stated that, " in each experi- 
 ment 1840 Ibs. of Knowles's Clifton coals were burnt; 
 a free-burning kind, much used in Manchester. The 
 boiler was one of Boulton and Watt's, 24-horse power, 
 waggon shape." 
 
 The following extract is from Table B., Appendix 
 No. 5, page 201, referred to in the evidence of 
 Henry Houldsworth, Esq. Vide Q. 1100, page 102, 
 July 27th, 1843. 
 
 
 Effect per 
 
 Water evapo- 
 
 
 
 Minute. 
 
 rated by 
 
 Econo- 
 
 AIR. 
 
 Coals 
 burnt. 
 
 Water 
 Eva- 
 porated. 
 
 1840 Ib. 
 of Coal 
 
 lib. 
 Coal. 
 
 mic 
 Effect. 
 
 
 Ibs. 
 
 galls. 
 
 galls. 
 
 Ibs. 
 
 
 No air 
 
 4-64 
 
 2-5 
 
 992 
 
 5-41 
 
 106 
 
 43 square inch constant 
 aperture 
 
 4-68 
 
 3-21 
 
 1,263 
 
 6-85 
 
 135 
 
 Air, regulated partly by 
 
 
 
 
 
 
 the eye and partly by 
 
 
 
 
 
 
 a scale, varying in some 
 
 
 
 
 
 
 degree with the action 
 of combustion. 
 
 4-43 
 
 3-09 
 
 1,280 
 
 6-94 
 
 134 
 
 No air 
 
 4-43 
 
 2-3 
 
 942 
 
 5-12 
 
 100 
 
MISREPRESENTATIONS AS TO ECONOMY. 113 
 
 The first effect of Mr. Houldsworth's published 
 statement was the industrious propagation by some 
 of the Manchester and Liverpool Journals, of the 
 fallacious inference that 35 or 36 per cent, in fuel 
 was to be saved by smoke-burning instead of 25 
 per cent, only, supposing his experimental data to be 
 right. That however was denied by many manufac- 
 turers, and the result was a request to Mr. Houlds- 
 worth to repeat any of his experiments likely to show 
 them so very desirable a result. This after some 
 preparation was agreed to, and I was appointed by 
 the firm of Geo. Clarke and Co. as their consulting 
 engineer to witness the experiment, and was also 
 retained for the same purpose by other manufacturers 
 who felt great interest in the subject. 
 
 These trial experiments took place by appointment 
 on the 19th and 20th December, 1843, and the 
 following summary of the results, after under- 
 going the revision of Mr. Billington, who super- 
 intended the experiments on the part of Mr. 
 Houldsworth, and a written acknowledgment of the 
 latter gentleman to their correctness, was transmitted 
 by me to Messrs. Clarke and Co., and the other firms 
 interested in the matter, also to Mr. Wm. Pairbairn 
 and other Engineers, who appeared to be so. 
 
114 FAILURE OF WILLIAMs's FURNACE. 
 
 SUMMARY. 
 
 Results of the experimental trial of the comparative 
 economy of Mr. C. W. Williams 9 s patent system of 
 smoke prevention and the ordinary plan. 
 
 " The exact results of the smoke-burning experi- 
 ments made at Mr. Thomas Houldsworth's works, on 
 the 19th and 20th of Dec. 1843, are as follows: 
 
 " At one boiler having Williams' s Patent Argand 
 Furnace attached that is with a permanent aperture 
 admitting a continuous current of air through a 
 perforated plate or " diffusion box" behind the 
 bridge, by the consumption of 1150 Ib. of coals, the 
 evaporation was 569^ gallons of water in 5 hours 22 
 minutes; and on the following day, namely, the 
 20th of December, 1843, with the same boiler, 
 the same quantity of coals from the same heap, 
 and every thing exactly in the same state as before, 
 except that the aperture for admitting air at the 
 bridge was kept carefully closed the whole time, and 
 the holes in the fire door plugged up, the evaporation 
 was 713J gallons in 5 hours and 20 minutes. The 
 experiments commencing each day at the same hour." 
 
 Eate of evaporation per Ib. of coal is accordingly : 
 With air admitted 4*95 Ib. water to 1 Ib. Coal. 
 "Without ditto.. 6-2 Ib. lib. 
 
MISREPRESENTATIONS AS TO ITS PERFORMANCE. 115 
 
 Difference 1*25 Ib. or 25 per cent, more steam in 
 favour of the ordinary plan and against smoke-pre- 
 vention, instead of 35 per cent, by parliamentary 
 evidence the contrary way ! 
 
 After so signal a failure as the above, what must 
 we think of a statement which the publisher has been 
 influenced by Mr. Williams to msezi twice over in an un- 
 authorized " Appendix" to a surreptitious edition, mis- 
 called by him the third of my " Eudimentary Treatise" 
 to the effect that Mr. Houldsworth had " as a result 
 of his reading Mr. C. W. Williams' s book on com- 
 bustion" reduced his consumption of coal from 20 to 
 17 cwt. per hour? My answer to this is, that 
 previous to his adopting Williams' s system, he was 
 using at the rate of 7| Ib. of coal per indicated horse- 
 power per hour full 20 per cent, more than the 
 average rate of other manufacturers at that time, 
 which left room for saving even by the adoption of 
 a bad plan. 
 
 Mr. Houldsworth^ s consumption was not therefore 
 the " ordinary," but an extraordinary and extravagant 
 consumption of coal. This is amply authenticated by 
 various duty report papers of Manchester engines now 
 before me ; a fact which constitutes him a very weak 
 authority on the subject, the only nominal (engi- 
 
116 PRACTICAL REMARKS ON SMOKE-BURNING. 
 
 neering) support he occasionally had in Manchester 
 to the contrary, notwithstanding. 
 
 Many other proofs abound, utterly condemnatory 
 of the perfect combustion notion, in its application to 
 steam engines ; but as that system is now perfectly 
 defunct, if it ever was alive, except on paper, I shall 
 here conclude with some observations printed several 
 years ago on "perfect" and "imperfect" combustion, 
 for the use of those who require a more rational theory 
 on the subject, and which I now take the liberty of 
 entitling 
 
 A THEORY OF THE BEST POSSIBLE COMBUSTION IN 
 STEAM ENGINE FURNACES. 
 
 It is true that smoke is a result of imperfect com- 
 bustion, but it is also true that combustion may be 
 still more imperfect without smoke, and be attended 
 with a much greater waste of fuel. In a steam engine 
 furnace, there never was, and never can be " Perfect 
 Combustion," even in theory much less in practice. 
 In the nearest apparent approach thereto, when no 
 visible smoke escapes from the chimney, there always 
 arises from a fire of tolerable thickness a certain 
 quantity of unconsumed inflammable gas, chiefly car- 
 bonic oxide, whilst at the same time, a very large 
 
AIR NECESSARY FOR COMBUSTION. 117 
 
 proportion (according to experiments by Peter Ewart 
 and John Dalton about one half) of the gaseous 
 products passing off by the chimney consist of at- 
 mospheric air unchanged, that is, containing its full 
 proportion, about one-fifth of oxygen. Now, since 
 it is impossible to increase the supply of oxygen, 
 which by combining with the fuel in the furnace is 
 alone the cause of all the heat produced, without at 
 the same time increasing the supply of the other com- 
 ponent of the atmosphere, consisting <A four-fifths of 
 it, namely, the nitrogen ; and allowing, as above, one 
 half only of the oxygen to be available, it follows that 
 about nine-tenths of the atmospheric air admitted 
 into the furnace, and heated to a temperature of 
 about seven hundred degrees, is carried off by the 
 chimney for no purpose whatever, except to enable 
 the remaining one-tenth to support the combustion 
 of the fuel. 
 
 An exception may be taken to this on the ground 
 that some part of this waste heat may be recovered 
 by an extended heating surface of the boiler; that, 
 however, is limited in practice by other circum- 
 stances, and does not affect the above conclusion as 
 regards the furnace considered by itself. 
 
 Whether heat is a material substance or not, which 
 
118 SUPPLIES OF AIR AND FUEL 
 
 is immaterial to this question, it is quite certain that 
 in its production from the burning of common bitu- 
 minous coal, the main elements concerned are carbon, 
 hydrogen, and oxygen, and that the complete conver- 
 sion of these three substances into carbonic acid and 
 
 ater without waste, is the only common-sense idea 
 that can be conceived of complete or f ' perfect com- 
 bustion." And, if we could have a continued supply 
 of oxygen without its accompanying nitrogen, such 
 complete combustion might be possible, but as we can 
 only have these two elements mixed as we find them in 
 the atmosphere, and one of them having to be separated 
 from the other, as they pass through the furnace, 
 whilst so large a portion as nine-tenths of the whole 
 is of no use in the process, the case is considerably 
 altered. 
 
 Take, for instance, any given ordinary furnace, and 
 supposing it to be in operation and supplied with fuel 
 at a given uniform rate, if we then suppose the air 
 supporting the combustion to be supplied at a uni- 
 formly increasing rate, it is certain that a maximum 
 point, in the relative proportions of the air and fuel, 
 must be somewhere arrived at, where the expenditure 
 of heat on the liberated nitrogen and other incom- 
 bustible products escaping by the chimney mustcoun- 
 
PROPORTIONATE AND CONTINUOUS. 119 
 
 terbalance the heat created by the consumption of that 
 portion of any combustible gas or smoke that would 
 otherwise pass off unconsumed in the same way 
 the former increasing as the latter diminishes, and 
 vice versa. 
 
 This maximum point of BEST POSSIBLE COMBUSTION 
 once attained, we can neither pass nor fall short of it 
 without diminishing the temperature and eventually 
 stopping the process ; or, in other words, the oxygen 
 which alone supports the combustion, must not 
 only create as much heat as is sufficient for heating 
 itself, but also as much as is required to heat up 
 to the same degree all the air or gases with which 
 it is in contact, otherwise the combustion will not 
 go on at the same rate, and consequently a lessened 
 supply of Steam to the engine results, and less 
 power, the only true measure of heat, is produced. 
 
 The natural conclusion from the above theory 
 which is also in strict accordance with all success- 
 ful experience is, that the most economical method 
 of firing a steam engine boiler, from which a con- 
 stant quantity of steam is required, must be by a 
 regularly uniform supply of fuel to the furnace, 
 and a similarly regular supply of air through the 
 .fire-grate "and no where else," with a uniform 
 
120 PRACTICAL SMOKE-BURNING. 
 
 though moderate emission of smoke, visible or in- 
 visible, from the chimney; visible within certain 
 limits of density of shade as the combustion is more 
 or less imperfect, being least imperfect when the 
 combustion is quicker and the resulting products 
 contain the largest proportion of carbonic acid gas 
 and steam, holding in suspension a thin grey colour- 
 ing of carbon or soot, which constitutes ordinary 
 smoke ; invisible when the combustion is slower and 
 more imperfect, allowing the carbonic acid first formed 
 to be replaced in the escaping products by a large 
 quantity of carbon, in the form of carbonic oxide 
 gas, thereby wasting, at least theoretically, nearly half 
 the available carbon of the coal. 
 
CHAPTER III. 
 
 EXPLOSIONS: AN INVESTIGATION INTO SOME OF THE 
 CAUSES PRODUCING THEM, AND INTO THE DETERIO- 
 RATION OF BOILERS GENERALLY. 
 
 How to obtain sufficient strength to resist the dis- 
 ruption of the materials of which boilers are composed 
 is one of the principal considerations usually advanced 
 in investigations respecting boiler explosions. Setting 
 this topic aside, for the present, and dismissing the 
 discussion of theories of explosions, we shall endea- 
 vour to collect here the practical results of the most 
 uniform experience relative to the explosions of 
 boilers which are imputable to common causes. 
 
 We shall also examine such experiments as illus- 
 trate the proper forms and dimensions of boilers in 
 common use, and shall recapitulate the principal 
 sources of weakness arising from ordinary tear and 
 wear, from improper management and from other 
 usual incidents in practice. 
 
122 EXPERIMENTS BY COMMITTEE 
 
 AMERICAN EXPERIMENTS ON EXPLOSIONS. 
 
 The most authentic illustrations of the inferior 
 limit of the thickness of metal proper for boilers, are 
 two experimental explosions purposely produced in 
 the course of a series of very important investigations, 
 undertaken by a committee of the Franklin Institute 
 of the State of Pennsylvania, at the request of the 
 American House of Representatives, for whom the 
 report of these experiments was first published in 
 America in 1836. 
 
 The immediate object of the two experiments in 
 question was "to observe accurately the sort of 
 bursting produced by a gradual increase of pressure 
 within cylinders of iron and copper." This course 
 was pursued because it had been assumed by many, 
 and indeed the opinion was very generally entertained 
 in this country as well as in America, that ruptures 
 produced in copper boilers would not bear the cha- 
 racter of explosions, but that a mere rending would 
 take place, giving an easy escape to the contents. In 
 pursuance of this investigation, two cylinders were 
 prepared of such a size as it was thought would make 
 a small thickness of material illustrate the question, 
 
OF FBANKLIN INSTITUTE. 123 
 
 " by rending at a pressure which was easily attain- 
 able/' 
 
 In this respect the committee would have found 
 less difficulty if they had made the boilers of a larger 
 diameter; for it appears they really had considerable 
 trouble in causing the boilers to explode at all. 
 o^owever, they did at last succeed, and the results 
 afforded a direct answer to the question between iron 
 and copper, proving the entire want of foundation for 
 the opinion which asserted the superior safety of the 
 latter. Collaterally, also, those results afford good 
 grounds for the first step of a general inquiry into the 
 causes of the explosions of boilers. 
 
 EXPERIMENTAL EXPLOSION. 
 
 The iron boiler used in this experimental explo- 
 sion was cylindrical, 10 inches long by 8| inches 
 diameter, and l-50th of an inch thick, with ends 
 l-20th of an inch thick, to which the curved portion 
 was fixed by rivets, nearly touching each other. A 
 single opening in one of the ends of the boiler 
 admitted the water, which was then furnished with 
 a screw, also with a tube and piston, connected 
 with a small spring weighing machine. 
 
AMERICAN EXPERIMENTS ON EXPLOSIONS 
 
 " Upon the cylinder of this machine a ring was 
 placed, which was moveable along the cylinder by a 
 slight pressure ; this ring was forced towards the end 
 of the cylinder nearest to the boiler head, as the spring 
 was bent, and remaining in its place as the spring 
 relaxed, served to register the maximum pressure to 
 which the piston had been exposed previous to observ- 
 ing it/'* 
 
 FIG. 3. 
 
 The small iron boiler thus prepared was half filled 
 with water, and placed on a charcoal fire, and the 
 steam got up ; but owing to a leak in the riveting, 
 the steam escaped so fast that the operators were 
 unable to burst the boiler on the first trial. The 
 boiler was, however, replenished with water, and 
 set lower in the fire, which was again urged, when at 
 last, with some difficulty, an explosion was produced. 
 
 * See the original Report, page 66. p I 1 
 
BY COMMITTEE OF FRANKLIN INSTITUTE. 125 
 
 So little dependence can, in general, be placed on 
 the relations made by witnesses of accidental ex- 
 plosions, and so rarely have explosions been inten- 
 tionally made for the purpose of illustrating this ques- 
 tion, that, for the sake of accuracy in preserving all 
 reliable facts, the different members of the committee 
 simultaneously addressed their attention to the 
 different circumstances which had to be observed at 
 the time the explosion took place. 
 
 " Part of the committee were engaged in observing 
 the progress of the experiment at this moment. The 
 fire was near the middle line of the boiler,* burning 
 not strongly near that line, but very rapidly below 
 the boiler ; the steam issued freely through the leak 
 before alluded to, and the whistling sound which it 
 produced, and which had increased gradually in 
 strength, as the experiment progressed seemed con- 
 stant. The length of time during which the steam 
 had escaped showed the water to be low, and induced 
 the supposition that a second time the object would 
 fail; when an explosion occurred." 
 
 * As the boiler rested horizontally in the fire, and was 
 half filled with water, this middle line and the water surface 
 would nearly coincide. 
 
126 INCIDENTS OF EXPLOSIONS 
 
 THE CROSS-LANE MANCHESTER EXPLOSION. 
 
 After recounting the incidents of this case of arti- 
 ficial explosion, I shall now proceed to describe some 
 of the cases of real explosion which have occurred in 
 practice. One of these cases is that of an explosion 
 which took place several years ago, by the bursting of 
 a small cylindrical boiler, of about three feet in dia- 
 meter, used for the purpose of working a six-horse 
 non-condensing engine, at a pressure of 60 Ibs. per 
 square inch. It had two safety valves, each of about 
 a square inch area, and both were stated to be in full 
 action at the time the explosion took place, having 
 commenced blowing off steam a few minutes before. 
 
 The result of this explosion was, that the wrought- 
 iron end of the boiler next to the furnace was torn 
 away, principally by splitting the angle iron, which 
 was barely f of an inch thick, and thrown more than 
 20 yards off, carrying the fireman six or seven yards 
 of that distance, who, together with another man, was 
 killed on the spot. The body of the boiler was driven 
 in a contrary direction, through both the external 
 walls of the engine-house, one nine and the other four- 
 teen inches thick, at the same time carrying away the 
 
OF BOILERS IN MANCHESTER. 127 
 
 steam-engine itself several yards into a field, at the 
 other side of the building.* 
 
 THE JERSEY STREET, MANCHESTER, EXPLOSION. 
 
 Another apparently similar kind of explosion to 
 that just described, took place in October, 1841, at 
 the Machine Manufactory of Messrs. Elce and Cot- 
 tarn, in Jersey Street, Manchester. This boiler, like 
 the previous one, was employed to drive a six-horse 
 high pressure, or non-condensing engine, having an 
 eight-inch cylinder and a two-feet stroke, working 
 usually at a pressure of from 26 to 36 Ibs. per square 
 inch. The safety-valve, which was of the common 
 kind, with a packed spindle and stuffing-box, was ad- 
 justed by means of a Salterns spring gauge, to blow 
 off at 40 Ibs., beyond which pressure it could not be 
 screwed down. 
 
 This boiler was a cylinder of 9 feet 6 inches in 
 
 * This explosion took place in October, 1832, at a saw- 
 mill in Cross-lane, Manchester, belonging to Mr. Greorge 
 Jones. The engine and boiler were both quite new, having 
 only worked a few days, although at the time of the explo- 
 sion the engine had been stopped for a few minutes for the 
 purpose of adjusting a strap on the machinery. 
 
128 STICKING OF SAFETY VALVE. 
 
 length,, with flat ends, 3 feet 10^ inches diameter. 
 It was made of good iron, f inch thick all through, 
 and had been some few years at work. The two ends, 
 or as the Americans call them, " heads " of the boiler, 
 were braced to each other by one longitudinal 
 wrought iron stay bar through the centre, attached at 
 each end by a wrought-iron strap and cotter. It was 
 the giving way of this strap, against which the cot- 
 ter was driven, through a slot in the stay bar, in the 
 usual manner adopted for low-pressure waggon boilers, 
 which was the immediate cause of the explosion. 
 The strength of the iron, however, at the place of 
 fracture, when examined by good judges, was pro- 
 nounced to have been capable of resisting a pressure 
 on the end of the boiler of at least 100 Ibs. to the 
 square inch. 
 
 STICKING OF SAFETY VALVES. 
 
 That the support above mentioned should have 
 given way when the safety-valve was free to open at 
 40 Ibs. per square inch, or less than one-half the 
 pressure that it was proved to be thoroughly able to 
 sustain, is one of the anomalies we are so frequently 
 meeting with in these investigations. I would here 
 call attention to this point ; because nothing would be 
 
STICKING OF SAFETY VALVES. 129 
 
 easier than to make short work of such cases, by 
 saying that the safety-valve must either have " stuck 
 or jammed" or otherwise must have had additional 
 weight put upon it at the time. This, in fact, was 
 the conclusion come to by three practical engineers of 
 the highest eminence, who agreed to deliver to the 
 coroner's jury a joint report on this case. 
 
 This sticking and jamming of safety valves, is, in 
 any case whatever, so extremely improbable, that a 
 resort to this explanation, without actual proof of its 
 existence, is much to be reprehended. In this pa,rti- 
 cular case, it is true the safety-valve was found broken 
 off and blown to a considerable distance, having its 
 spindle somewhat bent, and it had been wrapped with 
 a certainly improper packing of hemp ; but even if 
 the bending of the spindle had been done previously 
 to the explosion, (which was in the highest degree 
 improbable) the "sticking" thereby created in the 
 packing, could not have added many pounds per 
 square inch, to the resistance offered to the free escape 
 of the steam."* 
 
 * NOTE BY A3" EMINENT GOVERNMENT ENGINEE R. 
 
 " I fear that it is difficult to say what amount of force 
 is sufficient to raise a safety-valve whose spindle is bent, 
 and therefore I would suggest that * a measure ' be not as- 
 K 
 
130 A CONVENIENT PRETEXT. 
 
 Not a much better stalking horse than this uni- 
 versal sticking point is the criminal overloading, or 
 " making fast" the safety-valve. Any imputations of 
 this kind without the most clear and positive evi- 
 dence, both direct and circumstantial, is simply beg- 
 ging the whole question. There is very rarely, except 
 in the case of locomotives, any inducement to do any 
 thing of the kind, but very frequently the contrary, 
 as was very likely to be in the case before us. For 
 the engine had not started, and from the proved 
 careful habits of the engineman who was killed by the 
 explosion, it is much more probable that he opened or 
 eased the safety-valve, by removing all or part of the 
 load upon it, and my firm conviction was, at the time, 
 that he did do so, and that the boiler blew up on the 
 instant, or in a few seconds afterwards. 
 
 , signed. "I know a very serious case of rupture of a new 
 boiler, attended with loss of life, which was solely attri- 
 butable to a bent spindle, in my opinion, * * * but I 
 must confess that this conclusion, mine as well as yours, 
 being matter of opinion, simply, might be taken indiffe- 
 rently, according to the notion of the reader. 
 
 " I agree with you that ' sticking ' of safety-valves, pro- 
 perly so called, is extremely improbable. " 
 
EXPLOSIONS FROM WANT OF WATER. 131 
 
 DEFICIENCY OF WATER. 
 
 In the Jersey-street boiler, as well as in that at 
 Cross-lane, might be seen distinct traces of the water 
 having been too low. There were certain marks left 
 by the sedimentary deposits all around the interior of 
 the boiler, showing the high and low- water marks. These 
 indelible water lines gave evidence unmistakeable, that 
 the water had been too low. Since my attention was 
 first directed, many years ago, to these peculiar high 
 and low water deposit marks, I have personally in- 
 spected the internal condition of many hundreds of 
 steam engine boilers, and I have missed no oppor- 
 tunity of testing the accuracy of these indications of 
 water level, by a reference to other well- ascertained 
 facts, and have found that mutual accord which was 
 to have been expected. 
 
 In the Jersey-street boiler, some of the most dis- 
 tinct, and probably the most recent of those water- 
 marks were within twelve inches of the boiler bottom, 
 at which point, and at least an equal distance below 
 the proper level, it is extremely probable the surface 
 of the water was, when the explosion took place. 
 
132 REFERENCE TO AMERICAN EXPERIMENTS. 
 
 Now, it is to a deficiency of water to this extent, com- 
 bined with a sudden opening of the safety-valve, 
 causing a rapid ebullition, and a spreading of the 
 water over the super- heated side of the boiler, that I 
 principally attribute the frequency of explosions. 
 
 COMPARISON OF THE AMERICAN EXPERIMENTAL EXPLO- 
 SIONS WITH ACCIDENTAL EXPLOSIONS. 
 
 We may now return to the American experi- 
 ments, with the advantage of the illustrations afforded 
 by the two Manchester explosions, in which, in the 
 words of the committee, the " sort of bursting " pro- 
 duced in each case, was precisely of the same kind. 
 
 In the American Report, speaking of the iron 
 boiler, it is stated that " the explosion tore off one of 
 the heads b c (Kg. 3,) of the cylinder, projecting 
 the other parts of the boiler in an opposite 
 direction, carrying with them, a portion of the dis- 
 tance, the iron cylinder forming the furnace, and 
 scattering the fuel in every direction. 
 
 " The report attending the explosion, resembled that 
 from a small mortar fully charged, the steam mixed 
 with the smoke was not considerable in quantity, and 
 few marks of water were to be seen. The boiler head 
 
EXPLOSIONS FROM WANT OF WATER. 133 
 
 was thrown 15 feet, the boiler and spring register 
 about 6 feet, and the furnace, weighing about 45 
 pounds, was overturned and carried 4 feet. The 
 pressure indicated by the register, was 11J atmo- 
 spheres, (about 154 Ibs. per square inch.) 
 
 "In examining the boiler, it appeared that the 
 head b which was thrown off, had first struck against 
 the iron furnace, which had deflected it outwards ; 
 this is shown by the indentation c in the' figure. 
 This head was forced off all around, in the line of 
 rivets which attached the head to the boiler, the 
 metal remaining between the rivets being less than 
 the space occupied by them." 
 
 The accompanying figure (4j) will give an accurate 
 idea of the appearance of the boiler after its rupture. 
 
 LOSS OF WATER BY BLOWING OFF AND LEAKAGE. 
 
 The Committee then goes on to give the details of 
 an experiment with a copper boiler of the same dia- 
 meter, and of similar construction, which was ex- 
 ploded by a pressure supposed to be of about, sixteen 
 atmospheres, after having failed in the first attempt 
 owing to leakage, as in the former case. The sound 
 .or report was stated to be like that from an 8-inch 
 
134 REFERENCE TO AMERICAN EXPERIMENTS. 
 
 mortar. The copper was torn from the heads, un- 
 rolled, and irregularly bent; adhering to the heads 
 for only a short distance, as shown in the cut (Fig. 4), 
 and the heads were bent outwards. The thickness of 
 the copper at the line of rupture, varied from '025 to 
 035, say about 1-32 of an inch. 
 
 FIG. 4. 
 
 The description of the above carefully recorded 
 experimental explosions, shows that the steam was 
 allowed to rise gradually, in both cases, until the 
 boilers gave way. This gradual and slow increase in 
 the pressure of the steam, was in great part caused by 
 the leaks impossible to be avoided in the riveting of 
 
EXPLOSIONS FEOM WANT OF WATER. 135 
 
 sucJi very thin boilers ; a circumstance which enables 
 us to compare these experiments with other experi- 
 ments at boilers under different circumstances, 
 but in very similar conditions as to leakage of 
 water and steam, which we so frequently meet with 
 in ordinary practice. A not very dissimilar condition 
 is that of the continued escape of steam, from the 
 safety-valve or otherwise, and the consequent loss of 
 water during the time an engine is standing, and the 
 force-pump not at work, such as has been already de- 
 scribed in speaking of the Cross-lane explosion. Another 
 instance, is the case of a Locomotive when running on 
 a railway with the steam either blowing off, or being 
 continually consumed by the engine at a pressure or 
 strain upon the iron very much greater than either of 
 the Manchester explosions we have described, but 
 with this important difference, that while the loco- 
 motive is running, the full supply of water is easily 
 kept up. In nearly all explosions of locomotives that 
 have hitherto occurred, which have been very few, 
 and of these only a very small number have taken 
 place while the engine was running, there has been 
 always good reason for assuming a deficiency of water 
 in the boiler. 
 
 There is another condition that admits of a com- 
 
136 EEFEEENCE TO AMERICAN EXPERIMENTS. 
 
 parison with, the American explosion, and which is, 
 perhaps, the most important of any yet enumerated. 
 It is the condition of an ordinary stationary boiler 
 when the water surface is allowed to become too low 
 from unseen leakages at the lower part of the boiler 
 at certain times when the engine is standing, and 
 consequently the feed pump not at work. It will be 
 well to bear all particulars of frequent undue leakage 
 in mind for future application, as they have an im- 
 portant bearing on the general subject of boilers in 
 other respects besides those above named, and they 
 have been entirely overlooked by the American com- 
 mittee. 
 
 It appears that both the American boilers ex- 
 hibited proofs of the water having been too low at 
 the moment of explosion. Speaking of the copper 
 boiler, the report says : 
 
 " The marks of the sediment remained in the boiler, 
 and indicated that the water was about an inch deep 
 when the boiler exploded." Much more steam being 
 formed, and more water left, at the moment of explo- 
 sion, in the copper than in the iron boiler. It was 
 also observed that the steam increased " more rapidly 
 as the quantity of water diminished," and the com- 
 mittee add the following remark as a conjecture : 
 
SUGGESTIONS OF AMERICAN EXPERIMENTS. 137 
 
 " It is possible there may be a relation between the 
 space occupied by the water and that in which the steam 
 is formed) most favourable to the production of steam, 
 and when this was attained, a rapid rise of elasticity 
 took place. 33 
 
 It is much to be regretted that no farther experi- 
 ments were instituted in the direction of this sagacious 
 suggestion. The committee, however, were under the 
 necessity, from the nature of their instructions, of 
 investigating some particular averments of Mr. 
 Perkins, together with some episodical refinements 
 that seemed to have little connection with the great 
 facts they were in quest of. In reading the above 
 passage in italics, in the report, and knowing that this 
 branch of the inquiry ended there, it is difficult to 
 help lamenting that it is as if Columbus had turned 
 back when he was within sight of land. 
 
 Nothing remarkable occurred previous to the 
 instant of the explosion of the copper boiler, and the 
 members of the committee employed in the experi- 
 ments were engaged in observing the boiler at the 
 instant it exploded. When " a dense cloud of smoke 
 and flame, capped by steam, rose from the pit,* the 
 
 * See note A at the end of this chapter, concerning the 
 explosion of a large boiler at Bolton, Lancashire. 
 
138 SUDDEN PRESSURE WITHIN THE BOILER. 
 
 stones and combustibles were widely scattered, and 
 the boiler was thrown in a single mass about 15 feet 
 from the furnace." 
 
 This copper boiler was rent in the manner shown 
 in the figure (fig. 4), giving way in an irregular 
 line, just above the probable water line on one 
 side of the boiler, but not conforming to it. The 
 lowest points of the two heads of the boiler before the 
 explosion were at d and b (see fig. 4, page 134). 
 
 CONTRARY CONCLUSIONS DRAWN FROM THE AMERICAN 
 EXPERIMENTS. 
 
 The American committee conclude their remarks 
 on these experiments generally, by observing that 
 "all the circumstances attending the most violent 
 explosions may occur without a sudden increase 
 of pressure within the boiler." This, no doubt, is 
 true as & possibility, but it does not appear to me to 
 express correctly the circumstances usually attending 
 explosions in practice. The committee indeed do not 
 say that it does do so, but such a conclusion is a 
 natural inference from their averments. My experi- 
 ence, however, and a generalisation of all the facts 
 which have come under my observation during a 
 
COMPARISON OP CONCLUSIONS. 139 
 
 large practice in boiler engineering, conduct me to 
 a different conclusion. My opinion is, that, in the 
 most violent explosions that have occurred, there is 
 always a concurrence of circumstances attending them, 
 which show that a sudden increase of pressure within 
 the boiler has taken place, either at, or immediately 
 before, the moment of explosion; and further, that, 
 without such concurrent circumstances, or some of 
 them, the explosion would not have taken place at 
 all. 
 
 COMPARISON OP CONCLUSIONS. 
 
 If we briefly express the conclusion of the com- 
 mittee in similar terms to those used in the enuncia- 
 tion of our own theory it amounts to this, namely, that 
 all the circumstances calculated to produce an explo- 
 sion may " occur" without an explosion taking place. 
 While, in opposition to this, I maintain that those 
 same circumstances cannot "occur" simultaneously 
 without an explosion being produced. 
 
 Considering both these conclusions as separate 
 propositions, and one or the other to be proved by its 
 general agreement with facts as they arise in other 
 cases that come before us, we may begin by taking, 
 as an instance, the first experiment with the iron 
 
 UHI7BR3ITT 
 
140 SUGGESTIONS OF AMERICAN EXPERIMENTS. 
 
 boiler as given by the committee. Here tliere can be 
 no doubt that all the circumstances which they con- 
 sidered to be necessary to cause an explosion existed, 
 and yet no explosion took place. We, however, hold 
 that no sudden increase of pressure took place, and 
 therefore it was that, in the first instance, no explosion 
 ensued. Thus we see that one of the most important 
 circumstances is wanting. Let us however see what 
 all the facts were, by which circumstances were so 
 constituted as to fail in producing the explosion. 
 In the first place, the boiler was without a safety- 
 valve, unless the leak in the riveting may be con- 
 sidered as having the effect of an imperfect one. 
 Secondly, the water surface was proved to be con- 
 siderably below its proper level, and therefore the 
 upper portion of the sides was exposed to the risk of 
 becoming overheated. 
 
 Now, here are facts constituting two predisposing 
 causes, the shutting up the steam and the deficient 
 depth of water. But the first was confessedly im- 
 perfect, the leak allowing the steam to blow off, from 
 the commencement of the experiment, so fast that it 
 could not be raised to the bursting pressure, even 
 gradually, not a bad illustration, as the result 
 proved, of the safety of a badly fitted safety-valve, 
 
SUGGESTIONS OF AMERICAN EXPERIMENTS. 141 
 
 or one in bad order, not tight. And the other fact, 
 we may also show, was only imperfectly calculated to 
 produce a sudden increase of steam-pressure ', in the 
 only way that such a thing can be conceived to be 
 possible ; that is, by the water left in the boiler being, 
 by some impulse,, put bodily into motion, and caused 
 to flow over the over-heated metal. That the over- 
 heating of the sides, to some extent, took place, there 
 is no reason to doubt, although there is great reason 
 to doubt that the quantity of water left in the boiler 
 was sufficient for overflowing entirely the over-heated 
 part, even if such impulse had been given to the mass 
 of water as would have arisen from a slight increase 
 or enlargement of the leak, and which a little increase 
 in the pressure from a more rapid production of steam 
 would have produced. 
 
 CONCURRENCE OP CIRCUMSTANCES ATTENDING THE 
 FIRST EXPERIMENTAL EXPLOSION. 
 
 Now let us examine what changes of circum- 
 stances were made at the second trial with the iron 
 boiler when, at last, an explosion did " occur/' The Ee- 
 port states that the boiler was "replenished with water," 
 and we may safely infer that it would not be scantily 
 
142 INCIDENTS OF AMERICAN EXPERIMENTS. 
 
 replenished, seeing the Committee considered the pre- 
 vious deficiency to be the cause of the failure of the 
 first experiment, or, at least, one cause of its requir- 
 ing to be repeated. Then the boiler was " settled 
 lower into the fire, which was again urged," and the 
 whistling sound of the steam through the leak, which 
 before had increased, " seemed constant." Soon after 
 this, the explosion took place. 
 
 Here we cannot fail to remark, that the two main 
 circumstances, contributing to bring about the explo- 
 sion, the pressure and the low water, were present in 
 the same degree, or nearly so, as on the first trial ; 
 although the pressure might be a little higher, and 
 therefore calculated to produce, as it certainly did 
 produce, an enlargement of the leak or fracture in the 
 riveting ; which enlargement, in its turn, became the 
 third or actuating circumstance which, concurring with 
 the other two, caused the explosion of the boiler to 
 take place on the second trial. 
 
 The reader who has followed me thus far, will now 
 be in a position to enable him to make a practical 
 application of this reasoning to the case in hand. 
 
PRACTICAL CONCLUSIONS ON EXPLOSIONS. 143 
 
 PRACTICAL APPLICATION OF PRECEDING PRINCIPLES. 
 
 Settling the boiler "lower into the fire/" be- 
 sides raising the pressure of the steam higher in 
 the same time, would also, from the increased expan- 
 sion of the over-heated plates, tend to diminish the 
 leakage, thus diminishing the waste of water and 
 lowering the water-level more slowly, consequently 
 giving more time for the sides to acquire an undue 
 degree of heat from the nearer proximity of the 
 fire. 
 
 The proved effects arising from overheating the 
 sides, or other parts of a boiler, to a temperature of 
 from 400 to 500, are now well known to be first, 
 the repulsion of the water from the overheated sur- 
 face, producing a decreased amount of steam; but 
 immediately afterwards, as the temperature of the 
 metal is reduced down to the point of maximum 
 vaporisation, or a little below 40 0, by any thing 
 causing the water to flow over the overheated parts, 
 a sudden and greatly increased production of steam. 
 Now, had there been a safety-valve attached to this 
 experimental boiler, and had it been suddenly opened 
 either by the pressure of the steam or by design, this 
 
114 PRACTICAL CONCLUSIONS ON EXPLOSIONS. 
 
 flowing of the water over the sides would have taken 
 place, according to the theory here enunciated, pre- 
 cisely in the same manner as it was in reality produced 
 by a sudden enlargement of the leak or defect in the 
 riveting ; and from which the rent or rupture of the 
 whole boiler might have proceeded instantaneously. 
 The enlargement of the leak in this case, which a 
 slight increase of pressure was sufficient to effect, may 
 in fact be compared to the pulling of the trigger of a 
 gun overcharged, and ready to go off. Thus also, 
 according to my views, a good safety valve, if brought 
 into action, would have accelerated the explosion of 
 this boiler, or rather have caused it to take place 
 during the first trial. The opening of any ordinary 
 induction valve for blowing through, for the purpose 
 of starting an engine, or any other sudden liberation 
 of the steam, from any cause whatever would have 
 had the same effect. Any thing in fact tending to a 
 disturbance of the equilibrium, or level of the water 
 inside the boiler, would have answered the purpose. 
 This disturbance we are bound to believe was effected 
 by the rending of the boiler at the leaky or defective 
 seam of rivets on the second trial, which caused the 
 rise of the water level over the hot metal, and a con- 
 sequent sudden production of steam, by which the 
 explosion of the boiler was finally produced. 
 
SPHEROIDAL CONDITION OF WATER. 145 
 
 RECAPITULATION. 
 
 Respecting the peculiar phenomena relating to 
 the repulsion which takes place between highly heated 
 metal and water, known of late years, as the " sphe- 
 roidal condition of water," and which I consider 
 one p.f the corner stones of my theory of explosions 
 I shall speak more at length in another place."* At 
 present it will suffice to recapitulate the circumstances 
 already mentioned as among the most prominent 
 causes of boiler explosions. 
 
 First, The overheating of the boiler bottom or 
 sides, or the tops of the internal flues or furnaces, 
 which may be brought about by the water level 
 becoming accidentally too low. The bottom of the 
 boiler, however, may become overheated from many 
 causes without any undue depression of the water 
 level. One is the interposition of indurated sediment, 
 furr, or scale, between the water and the metal. 
 Another is the operation of a powerful blast or draught 
 through the fire, by which such a quantity of steam 
 is generated over a small portion of the boiler 
 bottom, that the water is partially or wholly driven 
 
 * See Note B at the end, on the " spheroidal " condition 
 of water. 
 
146 DEFECTS OF CONSTRUCTION. 
 
 away or repelled therefrom, in the " spheroidal 
 condition" referred to; and is often produced by 
 currents of air for smoke-burning purposes, admitted 
 in an injudicious, direction. 
 
 Secondly, The giving way of some small portion 
 of the boiler, which would not of itself constitute an 
 explosion, but which would be sufficient to liberate a 
 large quantity of steam or water, and create a sudden 
 disturbance of the water level, which circumstance, 
 concurring with the other conditions named, a sudden 
 rise in the pressure of the steam would result, and an 
 explosion ensue. 
 
 DEFECTS PECULIAR TO BOILERS COMPOSED OF RIVETED 
 PLATES. 
 
 Ordinary observers sometimes make the re- 
 mark that, in comparison to the frequent instances 
 of boilers bursting, we seldom hear of the bursting of 
 guns; and among sportsmen, never perhaps unless 
 overcharged. Without noticing the truth of the 
 allegation, which is perhaps not quite admissible, 
 there is one circumstance which renders the compari- 
 son unfair towards the boiler. A gun, a fowling 
 
WEAKENING EFFECTS OF RIVETS. 147 
 
 piece, for instance, though said to be in constant 
 use for a whole day, is only subject to pressure for a 
 fraction of a second at each discharge, not in all occu- 
 pying many minutes, -whereas the boiler has to resist 
 the pressure, and its variations continuously. The 
 general cause of the explosion is the same in both 
 cases. The boiler like the gun is too weak for the 
 charge it contains at the moment of the explosion. 
 " Why then," it will be objected, " can you not do 
 as the gunmakers do make your boilers stronger, 
 with an ample margin, for covering errors of calcula- 
 tion, and unseen defects in the material ; and then, 
 after a double or treble proof, ought not a boiler to 
 be as safe at least as a gun ? " This semi-military way 
 of putting the question, is the language, and conveys 
 the notions, not of military but of many civil engineers 
 and boiler makers of the highest practical talent, and 
 therefore deserves a categorical answer. 
 
 In the first place, putting out of consideration cast 
 iron boilers, because they are now seldom or never 
 used, although much might be said in their favour, I 
 answer that a boiler composed of plates of wrought 
 iron rivetted together, and overlapping each other at 
 their edges, is in a very different condition to a gun 
 or cannon composed of one nearly uniform piece of 
 
148 WEAKENING EFFECTS OF RIVETS. 
 
 metal. The latter quickly acquires a uniform tempera- 
 ture after any disturbing cause, and a more uniform 
 contraction or expansion throughout its whole sub- 
 stance is the result. The boiler, however, is neces- 
 sarily exposed to much greater inequality and extremes 
 of temperature ; it is consequently liable to corres- 
 pondingly greater variations of expansion and con- 
 traction ; and it will not be difficult to show that the 
 great contraction and expansion of this compound and 
 complicated structure of plates and rivets forming the 
 boiler, and which is going on continually while the 
 boiler is at work, as necessarily tends to tear it in 
 pieces, even without much assistance, from the 
 pressure of the steam. 
 
 As an example, in order to illustrate the destruc- 
 tive effects produced by the continually varying 
 expansion and contraction going on among the plates 
 of a riveted boiler, I may take the common case of 
 one 20 feet long by 6 feet diameter, with the fire 
 under its bottom, and containing an inside tube or 
 flue. Both boiler and flue being composed, as is 
 usual, of, say 10 rings of plates of about 2 feet long 
 each. 
 
 Now, on the first application of the fire to the 
 bottom of such a boiler, and before there is any 
 
EXPANSION OF EIVETED JOINTS. 149 
 
 ressure of steam at all, each of these plates imme- 
 diately acquires some intermediate temperature between 
 that of the fire outside and the water inside the boiler. 
 These two temperatures may be fairly considered to 
 average about 1500, and 100 degrees respectively to 
 begin with. The external surface of the wrought iron 
 plates where single, and the whole substance of the 
 outside portion of the plates where double or lapped 
 over the other, tending to the higher, and the inner 
 surface of the boiler bottom tending to the lower 
 temperature. The consequence of this is that the 
 expansion of the outer, exceeding that of the inner 
 surface, the boiler bottom becomes to some extent 
 convex outward, or towards the fire in a longitudinal 
 direction; thus, 
 
 FIG. 5. 
 
 The curvature of the plates is purposely exaggerated 
 in this figure in order to show more clearly the form 
 the boiler bottom tends to assume theoretically, and 
 not its extent ; on the application of the fire every 
 time the steam is to be got up; and this on the assump- 
 
150 IRREGULAR AND THEREFORE INJURIOUS. 
 
 tion that the joints of all the plates are perfectly and 
 firmly riveted,, and each plate of exactly equal strength 
 throughout. This however may be considered an 
 almost impossible condition in practice. There is 
 always some one or other of the seams of rivets less 
 capable of affording resistance to the immense force of 
 expansion than the rest, and these parts will there- 
 fore be the first to give way. The consequence is 
 that the boiler bottom more generally assumes the 
 form represented in Fig. 6. 
 
 FIG. 6. 
 
 Should there be any pressure of steam at all in 
 the boiler, and the plates be of equal strength, and 
 equally acted on by heat, of course the point of 
 greatest depression would be near the middle of the 
 length of the boiler. The greatest heat, however,. 
 
SUBSIDENCE OF BOILER BOTTOM. 151 
 
 being in the vicinity of the fire-bridge, is sufficient to 
 determine the position of this point at the nearest 
 seam of rivets to the bridge ; and there in fact this 
 depression is usually found. When permanent, it is 
 then commonly said by the stoker, " The boiler bot- 
 tom has come down." * 
 
 * Although this expression is usually applied to waggon- 
 boilers, the case is in point of fact one of collapse, similar to 
 that of a large fire-tube of a Cornish boiler. The subject is 
 treated on more at length in my " Essay on the Boilers of 
 Steam Engines," 1839, page 241. 
 
 As this work has been several years out of print, I give 
 the following extract from a second edition, which I have 
 had some time in preparation, together with an additional 
 volume of " Notes and Illustrations." 
 
 " It may be asked, if our theory of steam boiler explosions 
 be correct, how it is that we have not many more of them, 
 as the causes to which they are ascribed may seem to be of 
 almost every-day occurrence ? The answer is, that the 
 bursting of boilers is also a matter of every-day occurrence, 
 to an amount which the public generally are altogether 
 ignorant of. To be sure these burstings are not generally 
 called explosions, although in reality they are so, being 
 different only in degree. It would not be difficult to prove 
 that two or three of these minor explosions occur in Man- 
 chester every week ; but when no fatal consequences ensue, 
 
152 SUBSIDENCE OF BOILER BOTTOM. 
 
 With respect to the extent of the depression liable 
 to be produced from this cause. If we take the differ- 
 ence of temperature between the external and internal 
 surfaces of the boiler bottom, at 500, and allow- 
 ing iron to expand at "00007 of its length, for every 
 10 of Pah., or -00007 X50=-003'5 of its length 
 for 500, this will correspond to '84, or nearly an 
 inch of expansion in the total length of the boiler 
 bottom externally. 
 
 The immediate action of the fire is, of course, to 
 bend each plate separately, supposing the latter to be 
 
 and no particular damage is done to any adjoining property, 
 of course the circumstance never gets into the newspapers, 
 and no public notice is taken of it. 
 
 " Usually, the affair has quite another name when it occurs 
 with a waggon-boiler ; it is then said that the " boiler bot- 
 tom has come down ; " in other words the concave bottom is 
 forced down into a convex form, and sometimes the sides are 
 in like manner forced outwards, about the middle of the 
 length of the boiler. The consequence in the least violent of 
 these cases is, that the boiler is lifted up a few inches from 
 its seating by the bottom striking upon the top of the fire- 
 bridge. We also usually find every seam of rivets violently 
 strained, so that the water runs through the boiler-bottom 
 like a riddle, although there is seldom a hole of more than a 
 few inches in area. " R. A. 
 
DAMAGE CAUSED BY INCRUSTATION. 153 
 
 clean. But a boiler has commonly some sediment 
 deposited from the water, and any of the ordinary 
 deposit, however thinly spread over the bottom of 
 the boiler, being a very bad conductor of heat, per- 
 mits the temperature of the plates to rise higher, 
 extending through their whole thickness, and ex- 
 panding the plate, in some cases, to double the amount 
 supposed above. This condition greatly modifies 
 the heat in bending the plates, which become more 
 extended in length, and it adds considerably to the 
 curvature of the boiler bottom. Accordingly, we 
 constantly find, at particular times, a very serious 
 deflection of boiler bottoms downwards at about the 
 middle of their length. The depression commonly 
 admits of accurate measurement, to the extent of 
 a quarter of an inch or less, by placing a loose brick 
 on the top of the bridge, just a little out of contact 
 with the plates. And it regularly takes place in all 
 boilers, to a greater or less extent, every morning 
 before the steam is up, and before there is any pres- 
 sure whatever, excepting what arises simply from the 
 weight of water in the boiler. 
 
 Yery little observation will convince any one that 
 the peculiar action I have been describing really takes 
 place. The fact is notorious that all boilers are more 
 
154 UNEQUAL EXPANSION, A CAUSE OF LEAKS. 
 
 or less leaky when the fire is first applied to them for 
 getting up the steam ; possibly the leak is so minute, 
 in some cases, as to be scarcely discernible ; but, 
 generally, the leakage is sufficiently apparent when 
 there is a clear fire under the boiler. 
 
 Now it is well known that, so soon as the water 
 inside the boiler becomes heated, the leakage de- 
 creases, and, by the time it is boiling, and the steam 
 begins to rise, every leak in the boiler bottom, except 
 those that are running a full stream, is stopped, or 
 nearly so. The cause is, clearly, that the heat, so 
 soon as ebullition in the water commences, is carried 
 off, by the formation of steam, from the inner surface 
 of the plates, as rapidly as it is transmitted through 
 them from the fire ; and therefore, the temperature of 
 the plates falls, or becomes uniform and, consequently, 
 they again assume their original dimensions. The 
 usual expression of the stoker then, is, that the leaks 
 have " taken up," and by the time the steam is up, 
 or sooner, the boiler is " as tight as a bottle." It is, 
 however, the boiler bottom that is " taken up " by 
 contraction and an equalization of temperature on each 
 side of the plates. I am aware that this result is 
 commonly ascribed to sediment being driven into the 
 joints of the plates by the pressure ; but the stoppage 
 
LEAKS CEASE WHEN STEAM GETS UP. 155 
 
 of the leaks commences before the steam is up, and 
 the same phenomenon occurs in boilers which are 
 quite new, and which contain no sediment. 
 
 So far as a leakage of the kind just described may 
 diminish the quantity of water in a boiler, it is obvious 
 that it will be generally inconsiderable. A constant 
 daily repetition of this process, however, causes much 
 oxidation of the iron in the vicinity of the leaks, and 
 induces weakness in some particular direction across 
 the boiler bottom, which ultimately causes large open- 
 ings between the plates, and, then, great loss of water 
 results. And how the sudden loss of a large quantity 
 of water in a morning, or at other times, before the 
 steam is up, is likely to end in a violent explosion, at 
 or about the time the engine starts work, will be 
 sufficiently apparent from the explanations already 
 given. 
 
 HOW CHANGE OF FORM PRODUCES FRACTURE. 
 
 It is evident that a greater amount of expansion 
 and contraction will be produced at those joints of 
 the plates which are immediately over the hottest 
 parts of the fire than elsewhere. Suppose, for the 
 present, that the whole of the plates in the boiler 
 
156 
 
 STRAINS PRODUCED BY EXPANSION. 
 
 bottom are heated uniformly ; then, since the ends of 
 the boiler are firmly braced to each other by means 
 of the internal flue-tube, as well as by the upper half 
 of the cylinder, neither of which are so much affected 
 by the fire, it is clear that the expansion of one part 
 of the boiler is resisted by the other part. The 
 
 Ib a 
 
 FIG. 7. 
 
 greatest strain from the expansion of the boiler bot- 
 tom will be at the angles A and B (Kg. 6.) at % which 
 points, the rivets (if immoveably fast in the angle- 
 iron) must have a tendency to bend outwards frem 
 the longitudinal thrust of the plate in that direction, 
 as in Kg. 7, which is an enlarged representation of 
 
STRAINS PRODUCED BY EXPANSION. 157 
 
 the angle B in Kg. 6. The plate will also, some- 
 times, act as a lever in wrenching off the head of 
 the rivet ; or, as usually happens, by successive opera- 
 tions of this kind, the rivet-holes in the plates 
 become permanently enlarged, and break out. For 
 example, so soon as the water becomes sufficiently 
 heated to cause ebullition to commence, however 
 slightly, the temperature of the plates immediately 
 falls to 212, or to such a degree as corresponds with 
 the boiling-point at the time. And this point being 
 attained, of course, contraction of the bottom-plates 
 immediately ensues, as before described, co-equal with 
 the previous expansion. The thrust at the end rivets 
 now becomes a drag in the contrary direction, or 
 as shown by the position of the lines aa and &&, in 
 Pig. 7, which represent the directions to which the 
 varying position of the rivet respectively inclines, 
 according as it is acted on by the expansion or the 
 contraction of the boiler bottom. 
 
 If the rivets do not always give way, they enlarge 
 the rivet-holes, which, by this alternating action, 
 become oval or lengthened in the direction of the 
 strain and, ultimately, cracks are formed between the 
 rivet-holes and the edges of plates as shown in 
 Pig. 8, which is a plan or top view of Pig. 7. 
 
158 
 
 STRAINS PRODUCED BY EXPANSION. 
 
 One object I have in view here is to show that 
 severe strains upon the rivets of a boiler, arising from 
 undue expansion and contraction, may be increased 
 by the thickness of the plates, and that the destruction 
 of boilers from that cause is not confined to those 
 
 formed with angle irons and flat ends, but extends 
 also to those made with hemispherical or "egg" 
 ends, which are ordinarily considered superlatively 
 safe high pressure boilers. Such boilers are usually 
 of less diameter, and are consequently of greater 
 length, on which account they are more particularly 
 obnoxious to the defect I have been treating of, 
 arising from a proportionately increased amount of 
 expansion and contraction. 
 
EXPANSION PRODUCED BY HOT BRICKWORK. 159 
 
 As a practical example, I shall conclude by de- 
 scribing a boiler of this kind which came under my 
 observation a few years ago in London. 
 
 This boiler was 3^ feet diameter by 30 feet long, 
 and set up with the ordinary wheel draught which is 
 a very common, though a very improper mode of 
 setting a boiler of so small a diameter. The conse- 
 quence was that in order to obtain sufficient space for 
 draught in the side flues, the brickwork had to be 
 carried up considerably above the centre, and the 
 boiler was finally covered over with brickwork; a 
 dangerous practice though extremely common. 
 
 The reason for covering boilers in this way is of 
 course to retain the heat, which it certainly does, but 
 such a covering may be very detrimental to the 
 durability of the boiler. Thus, when the fire is 
 under the boiler, the temperature of the boiler bottom 
 may not generally be more than about 250, while 
 that of the side flues cannot be less than 500 or 600 
 degrees, and the brickwork resting on the top of the 
 boiler is seldom less than 350 or 400, as I have 
 frequently ascertained, and of course the iron in con- 
 tact with it will be of the same temperature, except 
 so far as the heat is carried off by the steam in con- 
 tact with the metal. Now here may easily be a 
 
160 EXPANSION PRODUCED BY HOT BRICKWORK. 
 
 difference of 200 or 30 0, causing a considerable 
 amount of expansion in the top of the boiler, and a 
 corresponding strain upon the rivets in the boiler 
 bottom. But supposing the boiler to be emptied by 
 running out the water at the end of the week for the 
 purpose of cooling and cleaning it out, or of cleaning 
 the flues : and further, for the purpose of cooling it 
 quicker, suppose that a quantity of cold water is 
 immediately run into the boiler, and let us see the 
 extent of the evil which takes place then. The hofc 
 brickwork will retain the upper half of the boiler, 
 upon which it rests, at full stretch ; while the lower 
 half, at least so far as the cold water extends, sud- 
 denly contracts, and instead of 200 we may have a 
 difference of 400 p between the top and the bottom 
 of the boiler, equivalent to about an inch in the 
 whole length of the boiler. 
 
 As near as could be judged, on close examination, 
 this was the precise extent to which several openings 
 in the seam across the boiler bottom amounted to 
 collectively. One or two of the dislocated parts 
 becoming jammed, and retaining their positions per- 
 mitted of exact measurement.. 
 
 This gradual disintegration of a boiler has no doubt 
 been frequently observed by others, although not 
 
INJURY FROM COOLING BOILER. 161 
 
 remarked upon. This particular example occurred at 
 a factory where it was the custom to clean out one of 
 the boilers every Sunday morning; for which purpose 
 the stoker commonly filled the boiler he intended to 
 clean immediately after letting out the hot water. 
 And the case is adduced as an example of those cases 
 where for years very great expenses were incurred in 
 repairing and remaking the boilers without the cause 
 of the defect having been discovered. Since, how- 
 ever, that practice of filling the hot boiler with cold 
 water has been discontinued, although the boilers are 
 now of thinner iron, larger diameter, and worked at 
 higher pressure, a boiler-mender is scarcely ever re- 
 - quired on the premises. 
 
162 
 
 NOTE A. 
 
 ( TO PAGE 137. ) 
 
 EXPLOSION AT BROOKES's FLAX MILL, BOLTON, 
 JULY 1ST, 1844. 
 
 Although some of the conclusions arrived at in 
 the American Report may admit of exception, evi- 
 dences tending to corroborate the general accuracy 
 of the committee's observations ought not to be with- 
 held. So far as two or three instances of explosions 
 go, I have had an opportunity of witnessing those 
 appearances, which, to my mind at least, confirm 
 the description given by the committee. As one 
 example, I may refer to the explosion of a large 
 boiler at the flax spinning mill, belonging to the late 
 John Brookes, Esq., in Little Bolton, Lancashire, 
 which I personally witnessed at the distance of about 
 300 yards from the mill, to which I was then on 
 my way, when the accident took place. 
 
 First, a column of dust arose to a considerable 
 elevation, in which some of the timbers of the roof 
 of the building, which enclosed the boiler, were seen 
 flying in different directions ; then arose a cloud of 
 
NOTE A. 163 
 
 smoke, which spread out above in a large black 
 canopy ; through this a column of steam and water 
 shot up to a very great height, which dispersed in mode- 
 rately large drops, like a slight shower of rain in 
 the direction of the wind, and to the distance of 
 about 4 or 500 yards from the mill. At the 
 same time, as a column of steam continued rising 
 from another boiler in connection with, and nearly 
 adjoining the one that burst, for about half a minute, 
 and as the lower part of the cloud of smoke and 
 dust began to clear away, flames commenced making 
 their appearance, arising from a high building ad- 
 joining that which had been blown up along with the 
 boiler; and which, in fact, as I afterwards found,, 
 had been set on fire by the burning coals from the 
 furnace of the exploded boiler being driven in through 
 the windows of the lower story of the building. 
 
 The boiler was of the waggon form, about 27 feet 
 long by 9 feet wide, and 10 feet deep, weighing pro- 
 bably about 10 tons, and called 40 horse power. 
 The lower portion, reaching up to the top of the 
 side-flues, about three-fourths of the whole, was 
 thrown in a single mass to about 20 yards from its 
 seat ; while the upper or semicircular portion, together 
 with the steam-pipes, safety-valve, nozzles, and other 
 
164 KOTE A. 
 
 attachments, were thrown to a great height, and fell 
 in the adjoining street, the ground of which was at 
 an elevation of more than 20 feet above the level of 
 the seat of the boiler. 
 
 The circumstance in which this Bolton Explosion 
 differed from those in the American experiments, is 
 remarkable, that is, in the report or sound produced. 
 For if the report produced by the bursting of a very 
 small boiler, only 10 inches long by 8 inches in diameter, 
 was like that from the discharge of a cannon, what 
 might we not expect from the explosion of a boiler 
 27 feet by 9, or about 5,000 times larger. But the 
 fact is, that neither myself nor a friend, whom I was 
 in conversation with at the time, heard any report of 
 that kind at all, bat only a rumbling sound such as 
 might be supposed to arise from the cracking of the 
 roof-timbers, the falling of the building, and the 
 blowing-off of the steam from the other boiler, which 
 had been working in connection* with the one that 
 exploded. There was a low continued rumbling noise, 
 as described by some who were nearer to the scene 
 of the explosion when it commenced, but it was 
 certainly not loud) and, indeed, scarcely audible to 
 us at the distance before mentioned, although our 
 attention was particularly directed to the cloud of 
 
NOTE A. 165 
 
 dust and smoke which arose from the mill. It being 
 not a little remarkable also that the subject of our 
 conversation at the time was the deterioration to boilers 
 from incrustation, and increased liability to accident 
 from working higher pressure, which had then recently 
 been adopted at this very mill, on account of attempting 
 to work the engines more expansively on the Cornish 
 system, but without the strong Cornish boilers. The 
 destruction in this particular case, in my opinion, 
 being greatly increased by using Mr. Williams' s patent 
 system of smoke-burning, which required the keeping 
 of a thick fire (over 18 inches), and a stream of cold air 
 passing up behind the fire-bridge. The area of the 
 fire-grate of the exploded boiler was about 60 square 
 feet, consequently it was charged at the time of the 
 explosion with nearly 100 cubic feet of burning fuel. 
 The effect of the sudden dispersion of such a mass of 
 fire may be easily conceived. That portion of the 
 boiler-bottom which extended over the fire-place, about 
 3 feet square, was torn right across, nearly in a straight 
 line from side to side, exactly at the position of the 
 bridge, besides being ripped up on one side through 
 the seating-plates, and across the front end at the angle 
 over the fire-door ; thus this large portion, being libe- 
 rated on three sides simultaneously, it was doubled 
 
166 NOTE A. 
 
 back on the other seating, as on a hinge or lite 
 the flap of a table, thereby opening out a hole of about 
 60 square feet in area, with an initial pressure of 
 steam at about 201b. per square inch. And immensely 
 reinforced as that pressure would be by contact with 
 the burning fuel in the furnace, it is not difficult to 
 divine the great force of the explosion, and the con- 
 sequent disastrous results that followed. 
 
 My first impression, on witnessing the commence- 
 ment of the scene just described, was that it was the 
 breaking out of a fire, and that, indeed, was the 
 general impression of great numbers of the people in 
 the streets of Bolton, who were making their way to 
 the scene of the catastrophe, until met by the crowd 
 of operatives, rushing out of the gates of the factory- 
 yard, many of them cut and bleeding from the effects 
 of the broken glass windows, which had been driven 
 in upon the workers in several rooms of a six-story 
 building, situated close to the boiler-house. It was 
 through these windows that the burning coals from 
 the large furnace were principally driven, which set on 
 fire the machinery inside the mill, where the conster- 
 nation and rush to escape was very great, as may easily 
 be supposed, there being in the whole factory about 
 540 people employed at the time. 
 
NOTE A. 167 
 
 Eespecting the peculiar sounds or reports pro- 
 duced by boiler explosions, it may be stated that the 
 strangest discrepancies occur in the statements of pro- 
 fessed eye and ear witnesses of this and similar 
 explosions. For instance, in this case, more than 
 one party testified to having heard the report more 
 than two miles off, like that from the discharge of 
 an immense piece of ordnance. All the London 
 papers, true to their character of exaggerators of 
 everything, had it, that the people of Bolton were 
 suddenly startled as with a loud clap of thunder ; 
 and some of them stated that the whole town was 
 alarmed as with an earthquake, an opinion which the 
 country papers also shared, after the London news- 
 paper reports reached them. 
 
 B.A. 
 
168 
 
 NOTE B. 
 
 ( TO PAGE 145. ) 
 
 The term "spheroidal" was, I believe, first applied 
 some years ago to that particular condition water is 
 in when repelled from a hot surface in the form of 
 roundish drops, by Mr. J. E. Bowman, then Pro- 
 fessor of chemistry at the Royal Institution, Man- 
 chester, and since of King's College, London. This 
 was on the occasion of his reading a lecture on the 
 subject of steam boiler explosions, in the above 
 institution, in the course of which he was the first, 
 perhaps, in this country, to give an account of, as 
 well as to show experimentally some of those remark- 
 able properties of water and other liquids when pro- 
 jected into red hot vessels, since made popular by 
 some curious performances at the meetings of the 
 British Association, and more recently at the British 
 Institution, by M. Boutigny, of Evreux, in Prance. 
 
 This gentleman, who had been some years engaged 
 in the prosecution of researches connected with the 
 
NOTE B. 169 
 
 subject, was, until the delivery of Mr. Bowman's 
 lecture, above referred to,* and its subsequent publi- 
 cation, generally supposed to be the first who had 
 attempted to " account for explosions on the suppo- 
 sition that water in them passes, under certain cir- 
 cumstances, into the spheroidal state." Sufficient 
 evidence, however, was furnished to Mr. Bowman 
 on that occasion, that I had been many years well 
 acquainted with the principle of the spheroidal con- 
 dition of water in boilers, its tendency to create 
 priming and to promote explosions, although I had 
 never thought of giving it that or any other distinc- 
 tive appellation. That I had several years prior to 
 its, no doubt independent, discovery by M. Boutigny, 
 also applied it to account for some of the explosions 
 of steam boilers, was a fact which Mr. Bowman very 
 handsomely acknowledged both in his lecture, which 
 was followed by a public discussion on the subject, 
 and also in his pamphlet, by quoting at length pas- 
 sages containing evidences thereof from a pamphlet 
 of mine, published in 1836-7. An instance of libe- 
 
 * " On some remarkable properties of water and other 
 fluids, with reference especially to the causes and prevention 
 of steam boiler explosions." By John Eddowes Bowman. 
 London : J. W. Parker, 1845. 
 
170 NOTE B. 
 
 rality and justice so honourable, though rare, among 
 scientific writers, that I cannot omit this opportunity 
 of publicly acknowledging it. And I may here notice 
 the fact that, although partly printed in 1836, my 
 book was written and the manuscript perused by 
 several friends nearly three years before that time. 
 The complete application of the discovery to the 
 theory of explosions was in reality made by me pre- 
 vious to 1830, when, in conjunction with my then 
 partner, Mr. Henry Wright, engineer of Manchester, 
 I made application for a patent, embodying the prin- 
 ciple of the repulsion of water from over-heated boiler 
 bottoms and front tube-plates of locomotives, being 
 one cause of the priming of steam boilers, as well as 
 causing explosions. During the years 1831 and 1832, 
 it is quite notorious, in Manchester, that I frequently 
 exhibited the principal experiments relative to it, in 
 explanation of the bursting of boilers. Small glass 
 boilers were purposely exploded with that view in the 
 presence of well known parties in numerous in- 
 stances. 
 
 The simplest mode in which those unused to ex- 
 perimenting may most conveniently at any time 
 readily demonstrate the "spheroidal condition of 
 water/' is that of heating the bowl of a large tea- 
 
NOTE B. 171 
 
 spoon over the flame of a candle until water runs off 
 without wetting it. Then, by the aid of a dropping 
 tube, or a quill, or any other means of measuring 
 into the spoon successive drops of water of the same 
 size, the leading facts of the repulsion of liquid in the 
 form of beads or spheroids become very apparent. 
 Thus a moderately small-sized bead or globule of 
 water, when the spoon is very hot, will be observed 
 to rotate rapidly on its axis, all the while moving 
 quickly about, supported by a thin film of steam, 
 and occupying half a minute or more perhaps before 
 it is entirely evaporated. If now, without reheat- 
 ing the spoon, and while, in fact, it is rapidly cool- 
 ing, we place another drop of water of exactly the 
 same size in the same position as the first, it will, 
 after assuming the same spheroidal appearance, 
 rapidly diminish in size, and evaporate entirely 
 away in two or three, or, at most, in a very few 
 seconds. A third drop so placed will be found 
 generally to disappear in less than one second; or, 
 if the experiment be carefully managed, the last 
 drop will be made to vanish instantaneously and 
 without assuming the globular or spheroidal form. 
 The temperature of the metal of which the spoon 
 consists will then of course be that of maximum 
 
172 NOTE B. 
 
 vaporisation, and which is usually found to be 
 considerably under 40 O p Pah. By the American 
 experiments it was found to be about 350, and 
 the temperature of perfect repulsion of drops of 
 water, projected into an iron bowl a quarter of an 
 inch thick was 405. The committee also refer to 
 a series of experiments by Professor Johnson, who 
 places the maximum evaporating point at between 
 304 and 320 Q , and in their general view of the 
 facts detailed, state that the repulsion between the 
 metal and the water is perfect at from 20 to 40 Q 
 above the point of maximum vaporisation, at which 
 temperatures the water does not wet the metal. 
 
 Some of the conclusions arrived at by the com- 
 mittee are as follow : 
 
 1. The temperature of maximum vaporisation, 
 both in copper and iron, is lower as the surface of 
 the metal is smoother, and the amount of vaporisa- 
 tion in a given time is much diminished. 
 
 2. The temperatures of maximum vaporisation,, for 
 copper and iron in similar states of surface, differ 
 between 30 and 40, the iron having the higher 
 point. 
 
 3. The time of vaporisation, at the maximum, is 
 less in the copper than in the iron, in the ratio of 
 
NOTE B. . 173 
 
 about 2 to I, probably, nearly in the ratio of the con- 
 ducting powers of the two metals for heat, which 
 are as 2J to 1. (See American Beport, Page 47.) 
 
 It must be observed that the above results are from 
 drops, or small quantities, of water, under atmo- 
 spheric pressure only. And, however interesting they 
 may be in a philosophical point of view, they cannot 
 be said to touch the practical question of the effect 
 of large quantities of water brought suddenly into 
 contact with hot metal, in producing explosions. 
 
 Accordingly, some experiments with cast iron 
 bowls, half an inch thick, containing large quantities 
 of water, placed over charcoal fires, indicated that the 
 highest point of greatest evaporation was placed, at 
 least, about 200 below red heat in daylight, and in 
 the most favourable circumstances, varying from 550 
 to 600 Fah. for wrought iron, and from 470 P to 
 526 P for copper. 
 
 In the course of the experiments of the American 
 Committee, it was observed that, with other liquids, 
 Alcohol for instance, at a certain temperatifcre of 
 the dish, that of the spheroid became stationary at 
 169iorl70, (theboiling-pointbeingl73) and that 
 it could not be raised higher ; indeed the temperature 
 of the spheroid became lower as that of the dish was 
 
174 . NOTE B. 
 
 higher. In my own experiments, that point not 
 appearing to me then to have any direct useful appli- 
 cation, I had only generally remarked that the tem- 
 perature of the globule of water must be lower than 
 212 from the fact that it did not boil. And it is 
 entirely to the delicately manipulated experiments 
 of Messrs. Bowman and Boutigny that we are 
 indebted for a knowledge of the fact, that the tem- 
 perature of a spheroid of water is invariably constant 
 at 205, or 7^ below its boiling-point, however hot 
 the crucible which contains it may be. Thus, also, a 
 spheroid of alcohol always stands at 170 or 3 below 
 its boiling-point ; one of ether is always 5 below, or 
 95 ; and liquid sulphurous acid which boils at 14, 
 never reaches so high even as that low temperature 
 when in the spheroidal state, but continues far colder 
 than melting ice, even though the crucible in which 
 it lies be all the time at the most intense white heat. 
 It was on this principle that M. Boutigny contrived 
 the feat of freezing water in red hot crucibles, and 
 afterwards that of handling melted cast iron. 
 
 E. A. 
 
175 
 
 APPENDIX, No. I. 
 
 REMARKS ON SMOKE-BURNING BY JOHN BOURNE, ESQ. 
 
 [The following remarks form a portion of a review 
 of Mr. diaries Wye Williams' s book on " The Com- 
 bustion of Coal and the Prevention of Smoke chemi- 
 cally and practically considered," which appeared in 
 the " Artizan" for February, 1843.] 
 
 The smoke evolved by every species of bituminous 
 coal, when burned in common furnaces, must neces- 
 sarily detract considerably from the calorific efficacy 
 of the fire, both on account of the direct loss of a 
 portion of the combustible which passes oft 7 in the 
 form of smoke, and is dissipated in the atmo- 
 sphere, as well as from the loss of the heat re- 
 quisite to convert the hydrocarbons, so dissipated, into 
 the gaseous form. Numerous attempts have been 
 made to obviate or diminish these sources of waste, 
 by admitting into the flue or furnace a stream of air, 
 
176 APPENDIX. 
 
 to accomplish the combustion of the inflammable 
 parts of the smoke ; but the difficulty of apportioning 
 the quantity of air admitted, to the varying wants of 
 the fire, has been found an insuperable objection in 
 the case of ordinary furnaces ; whilst the refrigeratory 
 effect of the excess of air it is necessary to admit, in 
 order to bring the atoms of the combustible and the 
 supporter within the range of combining attraction, 
 goes far to neutralize the increased heating power 
 consequent on their combination. In experiments 
 upon smoke-burning furnaces, conducted with great 
 care and skill, possibly some little saving may have 
 been repeatedly realized; but with the measure 
 of care and skill which furnaces can obtain in the 
 ordinary routine of practical operation, smoke-burning 
 has invariably been productive of a diminished effi- 
 ciency or an increased consumption. 
 
 All this Mr. Williams acknowledges ; but main- 
 tains that his is not a smoke-burning, but a smoke- 
 preventing furnace. Smoke, he admits, cannot be 
 burned advantageously ; but it is not smoke, he says, 
 but gas, that he attempts to consume. The difference 
 is certainly conceivable, and not unimportant ; yet, on 
 looking at the construction of Mr. Williams' s furnace, 
 we find that the furnace proper differs in no respect 
 
APPENDIX. 177 
 
 from common furnaces ; and the aeriform matter 
 which passes through the furnace-throat must, there- 
 fore, necessarily be of the usual description. The 
 whole of Mr. Williams' s plan, indeed, consists in let- 
 ting air into the flue by a multitude of holes ; but the 
 substance to which the air is admitted is identical 
 with that in furnaces of the ordinary kind ; and his 
 furnace is, therefore, just as much a smoke-generating 
 furnace as any furnace whatever. The difference be- 
 tween smoke and gas is simply this : one is the pro- 
 duct of imperfect or incomplete combustion, whilst 
 the other is not the product of combustion at all, but 
 of volatilization merely ; and, as combustion is carried 
 on in this gentleman's furnace, the substances flowing 
 past the diffusion-orifices, which are the product of 
 that combustion, cannot be coal-gas by any possi- 
 bility. The question really at issue is not whether it is 
 beneficial to admit air to gas in one hole or in many 
 holes, but whether, in the case of this furnace, it is 
 gas at all to which the air is admitted. To pretend 
 that smoke can be turned into gas, by letting in air 
 upon it by one hundred holes instead of by one or 
 two, is just as preposterous as to maintain that the 
 plant which, when watered with a common watering- 
 pot, is a lily, will be turned into a thistle if watered 
 H 
 
178 APPENDIX. 
 
 with a jug. In spite, then, of all the indignation Mr. 
 Williams has heaped upon "smoke-burning preten- 
 ders/' it is, in our eyes, undeniable that he is himself 
 one of the genus he so loudly condemns ; and as we 
 participate to a certain extent in his disapproval of 
 smoke-burning expedients, we are compelled to sur- 
 render him to his own reprobation. 
 
 The ineffectual and injurious character of Mr. Wil- 
 liams' s arrangements are, we think, very ably pointed 
 out in a report of Mr. Armstrong's addressed to a 
 Respectable manufacturing firm in Manchester, and in- 
 serted at p. 102 of the present work. 
 
 In answer to this statement, Mr. Williams contends 
 that when there is no smoke to be burned, there is 
 carbonic oxide, and that therefore a rush of cold air 
 through the diffusion orifices, at any time is impos- 
 sible. But if the furnace be made to produce carbonic 
 oxide in considerable quantity at all so as to combine 
 with the oxygen when there is no smoke, this carbonic 
 oxide must pass off unconsumed where there is smoke, 
 provided the smoke be consumed, and a great waste of 
 fuel must thereby be occasioned. In the case of ordinary 
 furnaces, it appears impossible indeed for Mr. Williams 
 to extricate himself from this dilemma ; he must either 
 have a current of cold air rushing at times through the 
 
APPENDIX. 179 
 
 diffusion orifices, cooling and injuring the boiler, or 
 large quantities of carbonic oxide continually escaping 
 into the chimney, so as to occasion a material waste 
 of fuel. On the whole, it appears to us that although 
 this project may be capable of affording some satisfac- 
 tion so long as it meets with the care due to a novel 
 and nurseling project as, indeed, a host of previous 
 schemes have repeatedly done yet that in the aggre- 
 gate of ordinary working, it will approve itself trou- 
 blesome, expensive, and pernicious. 
 
 Of Mr. Williams' s book, our verdict, we fear, must 
 be as unfavourable as of his invention ; yet it has re- 
 ceived high praise in various quarters ; and although 
 its admirers are not the best sort of admirers, we doubt 
 not their panegyric has been accepted by Mr. Wil- 
 liams as good sterling praise, and will probably render 
 distasteful any more discriminating analysis. Indeed* 
 the expectations of any author who has once tasted of 
 popular applause, are by no means easily satisfied. 
 Upon his first appearance before the tribunal of public 
 opinion, he will generally be content if he escape 
 without censure ; but his expectations rise with his 
 success, and the judgment he would at first have ac- 
 cepted with joy and gratitude, he will speedily come 
 to look upon as prejudiced and disparaging. Upon 
 any person, indeed, prominently before the public, a 
 
180 APPENDIX. 
 
 word of disapprobation falls with prodigiously in- 
 creased weight : so long as he remains in obscurity, 
 reproof is unattended with disgrace because it is ne- 
 cessarily unwitnessed, but the crowd he brings around 
 him by Ins triumph, if it adds to the brilliancy of 
 success, fearfully aggravates the penalties of failure. 
 Every voice which swelled the measure of his fame 
 will add to the ignominy of his degradation ; and a 
 measure of praise which would have exceeded the 
 hopes of his earlier ambition will now only suggest 
 humiliating ideas of his unfitness for the position he 
 has so incautiously usurped, and the derision and dis- 
 appointment his incapacity has excited. 
 
 An inquiry into the phenomena attendant upon the 
 combustion of coal divides itself into two parts. 
 First, The determination of the chemical constitution 
 of the coal ; and, Second, The determination of the 
 quantity of air requisite for the combustion of its 
 constituents. Mr. Williams has gone into both of 
 these subjects at considerable length. He has given 
 us a compilation of authorities showing what the 
 chemical composition of different species of coal is, 
 and has favoured us with several chapters and a mul- 
 titude of diagrams to point out that carbon and 
 hydrogen combine with oxygen in definite proportions. 
 
APPENDIX. 181 
 
 In the whole of these most ingeniously constructed 
 chapters, there is not a single remark of the least 
 worth or moment; and in the whole length and 
 breadth of the book there is nothing new, except its 
 errors and the magisterial solemnity with which the 
 most trite and insignificant truths are reproduced and 
 paraded. Indeed, Mr. Williams seems very fond of 
 burning his gas in the blaze of noon-day. He de- 
 votes pages to prove self-evident propositions, and 
 takes infinite pains to convince sceptics of things no- 
 body ever thinks of doubting. He continually speaks 
 of atoms as if he himself had found them out, and as 
 if an introduction to so difficult a theme inspired ex- 
 traordinary trepidation ; as in page 40, for example 
 ytere he encouragingly tells us " not to feel alarmed 
 at this introduction to elementary atoms and chemical 
 equivalents." In pages 27, et seq,, the discovery is 
 announced to us, that when fresh coal is thrown upon 
 a fire, the fire is afterwards not quite so hot as before ; 
 in pages 28 and 29, we are assured that heat is neces- 
 sary to expel gas from coals ; in page 35, that a com- 
 bustible as well as a supporter are indispensable to 
 combustion; and in page 37, that the combustion of 
 gas is accomplished, "not by its combination with the 
 .air, as is the vulgar and dangerous notion, but with 
 
182 APPENDIX. 
 
 the oxygen of the air the supporter of flame the 
 heat-giving constituent of the air." In page 91, we 
 are told, " Without sufficient time, nothing short of a 
 miracle could satisfy the required extent of diffusion- 
 Nature, however, does not operate by miracles, but by 
 defined laws and progressive means;" and in page 
 129, we are assured that combustion cannot take 
 place without air ; " that providing heat is not pro- 
 viding air, neither is decomposition combustion." In 
 page 11, we are told that Sir Humphrey Davy was an 
 eminent man; in page 20, that Dr. Faraday is the 
 first electrician of the day ; and in page 41, that John 
 Dalton is a writer of merit. At page 70 commences 
 a chapter of 30 pages for the purpose of pointing out 
 that as it is oxygen which supports the combustion is 
 a furnace, the air supplied to the furnace must not 
 have been deprived of its oxygen previously, else it 
 will not do : for thus wisely and thus learnedly ar- 
 gues this philosopher, " If oxygen be not present in 
 the air, how can it otherwise be obtained ? How can 
 we effect a union with a thing which is not?" 
 
 In extenuation of the marvellous superficiality of 
 this gentleman' s treatise, it may, perhaps, be urged 
 that he wrote not for scientific, but for practical men. 
 This argument might, perhaps, have some weight if 
 
APPENDIX. 183 
 
 by practical men were meant our working boiler smiths 
 and bricklayers, who for the most part are supposed 
 to know as much of chemistry as of the (Elic redupli- 
 cation ; yet, even in this case, we do not altogether 
 see how those persons should be induced to read this 
 book more readily than some of the numerous chemical 
 works to which they already have access. Mr. Wil- 
 liams, however, informs us that he does not address 
 himself to so unpromising an auditory, but to those 
 by whom engineering works are directed and designed. 
 ' Are then our bricklayers or boiler-makers to become 
 chemists? No. But those who direct those who 
 assume the charge of teaching them to construct the 
 numerous descriptions of furnaces with which this 
 country abounds, should be masters of the leading 
 principles on which their art is based, and the success 
 of their operation depends/ of which it would appear 
 they at present know nothing. Thus in page 2, Mr. 
 Williams informs us, that, even the most experienced 
 engineers know very little about the boiler in page 
 
 3, that in the construction of boilers engineers are 
 without any fixed principles to guide them in page 
 
 4, that he has watched the efforts of engineers to arrive 
 at some degree of certainty, and that he has perceived 
 the absence of any intelligible or well-founded prin- 
 
184 APPENDIX. 
 
 ciple in the boiler in page 5, that instead of improve- 
 ment there has been latterly retrogression, and that 
 well-established houses even yet know very little of 
 the principles of perfect combustion, or of the economy 
 of fuel. Prom these and numerous other passages, 
 which might be cited, it would appear to be this gen- 
 tleman's doctrine that engineers are a very ignorant 
 and stupid race of persons ; that though living in 
 England in the nineteenth century they are unac- 
 quainted with the simplest and most familiar truths 
 of chemistry ; and while possessing the reputation of 
 producing those miracles of ingenuity which carry 
 their fame to the verge of civilization, that they exist 
 in a state of mental stupor which the most besotted 
 Turk could scarcely hope to emulate. A person, in- 
 deed, who derived his only information on this sub- 
 ject from Mr. Charles Wye Williams, might imagine 
 our mechanists to be the descendants of some barba- 
 rian horde on whom a hereditary curse rested, doom- 
 ing them to an eternal degradation ; who remained 
 rude and untutored even in the centre of civilization, 
 and whom the flame of science could neither melt nor 
 quicken, nor the lessons of experience instruct. It is 
 not astonishing, therefore, that Mr. Williams should 
 speak with much confidence and coolness of the ab- 
 
APPENDIX. 185 
 
 surdities of the practice of our engineers, which in 
 pages 34, 72, 73, 74, 127, and, indeed, in almost 
 every page throughout the volume, he most indus- 
 triously exposes. He takes especial care to make 
 manifest the shallowness of Tredgold, and the erro- 
 neous notions of Watt, which he of course contrasts 
 with his own higher skill and superior illumination, 
 and finding himself unable to refute what they do say, 
 wisely confines his refutation to what they do not say. 
 In page 134, he states, 'the erroneous view of the 
 combustion of the gases began with Watt / but after 
 handling poor Watt very severely for his manifold 
 shortcomings, he kindly winds up in the following 
 patronizing strain: ' But let justice, however, be done 
 to Watt. It is not his fault that the errors he com- 
 mitted should continue to be repeated/ which our 
 present engineers are, it appears, wrong-headed 
 enough to do. The following epithets are therefore 
 unsparingly applied to the practice of those obdurate 
 persons ; f erroneous/ e lamentably erroneous/ f neglect 
 of chemistry/ 'notable instance of neglect of chemistry/ 
 'abortive attempts/ 'great practical and chemical error/ 
 'palpable oversights/ ' unsound principles/ 'chemical 
 blunder/ ' utterly at variance with chemical propriety/ 
 and a host of other equally decorous and appropriate 
 
186 APPENDIX. 
 
 expressions. The secret of all this we suppose is, that 
 Mr. Williams plumes himself not a little upon the 
 smattering of chemistry he appears to have acquired, 
 and in the simplicity of his heart imagines that be- 
 cause our leading engineers do not think it consistent 
 with their dignity to become lecturing itinerants, or 
 to be eternally flashing their attainments in the eyes 
 of ignorant spectators, they know nothing of the most 
 familiar scientific truths, and -pay no regard to them 
 in their practice. If Mr. Williams could only see 
 himself as he is seen by others if he could only per- 
 ceive the ridicule he draws upon himself, by harping 
 everlastingly about chemical principles, and chemical 
 blunders and which we can assure him raises the 
 secret laughter of even the most favourably affected 
 he would, we are sure, gladly retire into the obscurity 
 for which Providence manifestly designed him, and 
 leave the contention for distinction to those who have 
 something better to offer as credential than a flood of 
 scientific jargon, or the pitiful pedantry of a boiling 
 empiric. J. B. 
 
187 
 
 APPENDIX, No. II. 
 
 AMERICAN EXPERIMENTS ON EXPLOSIONS, 
 
 Made by order of the Treasury Department of the 
 United States, in which, among other instructions on 
 the subject, directions were given. 
 
 " To observe accurately the sort of bursting produced 
 by a gradual increase of pressure within Cylinders of 
 Iron and Copper. 
 
 " It has been contended by some, that ruptures pro- 
 duced by a gradual increase of pressure within steam 
 boilers do not bear the character of explosions, but 
 that a mere rending takes place, giving escape to the 
 contents. This has been assumed to be especially the 
 case with copper boilers. To make the observation 
 required by the above question, cylinders of iron and 
 copper were prepared, of sufficient size, to make a 
 small thickness of material answer for rending by a 
 pressure which was easily attainable. Two experi- 
 ments made, one with an iron and another with a 
 copper cylinder, afforded so direct an answer to the 
 query that it was not deemed necessary to carry the 
 experiments further, especially as they were tedious, 
 and not without danger. A further experiment of the 
 
188 APPENDIX. 
 
 same tenor, resulted from a trial of Perkins's assertion 
 in regard to the effect of making an opening in a vessel 
 containing water, and heated to a high temperature. 
 
 ' ' The boilers used were cylindrical, eight and a half 
 inches in diameter, and ten and twelve inches respec- 
 tively in length, of iron "02 inch thick, and of copper '03 
 inch thick, having iron heads '05 inch thick, to which 
 the convex surface was fixed by iron rivets, placed nearly 
 touching each other. A single opening in the middle 
 of one of the heads of each boiler was provided to in- 
 troduce the water, and was furnished with a screw, 
 into which to insert a tube and piston, connected with 
 a small spring weighing machine, which is represented 
 at a in the cut on page 124. Upon the cylinder of 
 this machine a ring was placed, which was moveable 
 along the cylinder by a slight pressure : this ring was 
 forced towards the end of the cylinder nearest to the 
 boiler head, as the spring was bent, and remaining in 
 its place when the spring relaxed, served to register 
 the maximum pressure to which the piston had been 
 exposed previous to observing it. 
 
 "The iron boiler was placed in a heavy cylinder of 
 wrought iron, which served as a furnace, the axis of 
 the boiler being nearly horizontal, and that of the 
 furnace cylinder vertical. The boiler, having been 
 
APPENDIX. 189 
 
 half filled with water, was placed upon a fire of char- 
 coal, and when the water boiled, the register machine 
 for the pressure was screwed in. 
 
 " The place selected for the experiments was in a de- 
 serted quarry on the banks of the Pennypack, near 
 Holmesburgh. The high bank served as a protection, 
 by the aid of which the experiments were viewed with 
 little danger. A wire and cord were attached to the 
 head of the boiler, to draw it from the fire when the 
 latter required to be replenished. A leak in the 
 riveting of the iron boiler allowed so much steam to 
 escape that the boiler did not give way on the first 
 trial. As soon as the escape of steam was observed to 
 cease, the boiler was removed from the fire and again 
 half filled with water. The fire was urged, and the 
 boiler settled lower into it, and by once replenishing 
 the fuel, without removing the boiler, an explosion 
 was produced. Part of the committee were engaged 
 in observing the progress of the experiment at this 
 moment. The fire was near the middle line of the 
 boiler, burning not strongly near that line, but very 
 rapidly below the boiler; the steam issued freely 
 through the leak before alluded to, and the whistling 
 sound which it produced, and which had increased 
 gradually in strength as the experiment progressed, 
 
190 APPENDIX. 
 
 seemed constant. The length of time during which 
 the steam had escaped showed the water to be low, 
 and induced the supposition that a second time the 
 object would fail; when an explosion occurred. The 
 explosion tore off one of the heads, d c, of the cylinder, 
 projecting the other parts of the boiler in an opposite 
 direction, carrying with them for a portion of the dis- 
 tance, the iron cylinder forming the furnace, and 
 scattering the fuel in every direction. The report 
 attending the explosion resembled that from a small 
 mortar (eprouvette) fully charged, the steam mixed 
 with the smoke was not considerable in quantity, and 
 few marks of water were to be seen. The boiler head 
 was thrown fifteen feet, the boiler and spring register 
 about six feet, and the furnace, weighing about forty- 
 five pounds, was overturned and carried four feet. 
 The pressure indicated by the register was eleven and 
 a quarter atmospheres. 
 
 " In examining the boiler it appeared that the head, 
 5, which was thrown off, had first struck against the 
 iron furnace, which had deflected it outwards ; this 
 is shown by the indentation, b c, in the figure. This 
 head was forced off all around in the line of rivets 
 which attached the head to the boiler, the metal re- 
 maining between the rivets being less than the space 
 
APPENDIX. 191 
 
 occupied by tliem. Tlie convex surface and the other 
 head were thrown likewise against the furnace, and 
 the head indented at d e, overturning the furnace and 
 carrying it four feet, as already stated. The boiler 
 finally struck against the side of the bank of earth. 
 The piston of the weighing machine was somewhat 
 bent in the experiment. 
 
 "The circumstances of this experiment show that the 
 steam rose quite gradually on account of leaks in the 
 boiler, increasing, probably, more rapidly as the quan- 
 tity of water diminished, the intensity of the fire 
 meanwhile increasing. That at a certain period the 
 tension within had attained about eleven atmospheres, 
 when the boiler exploded violently. 
 
 " The accompanying figure (3) will serve to give an 
 accurate idea of the appearance of this boiler after 
 its rupture. 
 
 " The cylinder of copper, before referred to, was next 
 put in the place of the iron boiler, and the fire again 
 kindled; the general arrangements being as before 
 described. This boiler being longer than the former 
 would not descend so far into the furnace, and an at- 
 tempt to raise the steam sufficiently high to burst it 
 failed : there was a considerable leak in the junction 
 of the curved surface with one of the ends. When 
 
192 APPENDIX. 
 
 the water was nearly exhausted, the fire having passed 
 its period of greatest heat, the cylinder was removed 
 and water again introduced, filling about three-fourths 
 of its capacity. A new furnace was constructed of 
 stones, allowing the boiler to rest more closely upon 
 the fuel, and affording a screen from the wind which 
 was blowing quite strongly. The part of the boiler in 
 which the leak had been observed was turned down- 
 wards, but a similar escape was found for the steam in 
 the part now uppermost. The tension of the steam 
 appeared to increase very slowly, and the fire passed its 
 best action without effect ; it was renewed, and as the 
 water became lower the tension of the steam increased 
 considerably. As before, nothing remarkable occurred 
 previous to the instant of explosion, and the members 
 of the committee, employed in the experiments, were 
 engaged in observing the boiler at the instant it ex- 
 ploded. A dense cloud of smoke and flame, capped 
 by steam, rose from the pit ; the stones and combus- 
 tibles were widely scattered, and the boiler was thrown, 
 in a single mass, about fifteen feet from the furnace. 
 The noise attending this explosion was like that from 
 the firing of an eight-inch mortar. 
 
 " The boiler was rent as shown in the accompanying 
 figure (4), giving way in an irregular line just above the 
 
APPENDIX. 193 
 
 probable water line on one side of the boiler, but not 
 conforming to it. d and 5 were the lowest points in 
 the two heads before the explosion. The sheet of 
 copper was torn from the heads, nnrolled and irregu- 
 larly bent, adhering to the heads for only a short dis- 
 tance near the top of each ; and the heads were bent 
 outwards. The thickness of the copper along the line 
 of rupture yaries from '025 to *035 of an inch, and 
 the metal appears to have been highly heated at one 
 end of the torn portion. The piston of the spring 
 gauge was bent, the screw which attached it to the 
 boiler broken, and the whole instrument otherwise in- 
 jured ; it appeared that the wire intended to draw the 
 boiler off the furnace had slipped and impeded the 
 action of the piston, so that no register of the amount 
 of force producing this explosion was obtained.* 
 
 " The circumstances, as before, show that the steam 
 was allowed to rise gradually until the boiler gave 
 way. It is possible that there may be a relation be- 
 tween the space occupied by the water and that in 
 
 * "Assuming the strength of copper at 36,000 Ibs. to the 
 square inch, and that it was uninjured by the heating, neg- 
 lecting also the effect of temperature, the bursting pressure 
 appears by calculation, to have been about sixteen atmo- 
 spheres. It was, no doubt, less than this." 
 
 
194 APPENDIX. 
 
 which the steam is formed most favourable to the 
 production of steam, and that when this was attained 
 a rapid rise in elasticity took place ; but there were 
 no circumstances observed which would confirm such 
 a view., and if it were correct it would only affect the 
 conclusion as far as the increase of tension might have 
 been rapid from such a cause. 
 
 " As in the former case the marks of the sediments 
 remained in the boiler, and indicated that the water 
 was about an inch deep when the cylinder exploded. 
 Much more steam was formed, and more water left 
 than in the first experiment. 
 
 " These experiments, together with the one referred 
 to in a subsequent part of this report, are direct and 
 conclusive ; they show that all the circumstances at- 
 tending the most violent explosions may occur without 
 a sudden increase of pressure within a boiler. There 
 can be no doubt, however, that if particular portions 
 of a boiler are much weaker than other parts, they 
 may give way in time to prevent such a catastrophe." 
 (From " REPORT of the Committee of the Franklin Insti- 
 tute of the State of Pennsylvania for the promotion of 
 the Mechanic Arts, on the EXPLOSIONS or STEAM 
 BOILEES. Part I. Containing the first report of ex- 
 periments made by the Committee for the Treasury 
 Department of the United States." Philadelphia, 1836.) 
 
CONCLUDING NOTICE. 
 
 I have been constrained, only by considerations of 
 space, to omit descriptions of several excellent boilers 
 both of the multitubular and flue construction. Among 
 the former are those of ANDREW (locomotive), BAR- 
 RANS (cup surface), BURNEY (river boat), GORDON of 
 Stockport, and HOLCROFT of Manchester. And among 
 the latter are CAMERON'S (upright conical furnace), 
 COWBURN'S (cellular), and DUNN'S (patent vertical), 
 all of which are among the best of their respective 
 kinds. 
 
 ERRATA. 
 Page Line 
 
 44 9 from bottom for " as," read of. 
 110 6 " " conducted," read witnessed. 
 
 124 1 " after "page 66," add^. 187 of this look. 
 13310 " for " Fig, 4," read Fiy. 3. 
 
 PRINTED BY G. 
 
 HATTON 
 
ROBEET AEMSTBQNG, C.E. 
 
 CONSULTING MECHANICAL ENGINEER, BOILER, 
 A.ND FURNACE ARCHITECT, 
 
 AND 
 
 SURVEYOR OF STEAM ENGINES AND OTHER 
 MACHINERY, 
 
 65, FENCHURCH STREET, LONDON. 
 
 ME. ARMSTRONG begs to intimate that lie may be consulted 
 on any engineering question at the above address, either by 
 letter, or personally on an interview having been previously 
 arranged. 
 
 Mr. Armstrong's large experience as a boiler and furnace 
 architect, for nearly thirty years, warrants him in assert- 
 ing that those who consult him, either as to the efficiency, 
 economy, and durability of their boilers, or the prevention 
 of Smoke in Furnaces, so as to comply with the requisitions 
 of the Act of Parliament, will ensure the realization of the 
 utmost measure of success yet attained, and the latest steps 
 of ascertained practical improvement without encountering 
 the risks incident to the various charlatan projects presented 
 for public acceptation. 
 
 Mr. Armstrong's fees are very moderate, and any work 
 entrusted to him is executed with despatch. 
 
 * # * Preparing for publication 
 
 THE MODERN PRACTICE OF FURNACE 
 
 ARCHITECTURE, 
 
 Comprehending CHIMNEY SHAFTS for Steam Engines and 
 FIREPLACES for Dwelling-houses. 
 
14 DAY USE 
 
 RETURN TO DESK FROM WHICH BORROWED 
 
 LOAN DEPT. 
 
 This book is due on the last date stamped below, or 
 
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 Renewed books are subject to immediate recall. 
 
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