NA TURE 



381 



THURSDAY, FEBRUARY 27, 1872 



THE GROWTH OF THE STEAM-ENGINE 



A History of the Growth of the Steam-Engine. By 

 Robert H. Thurston, A.M., C.E., Professor of Mechani- 

 cal Engineering, Stevens' Institute of Technology, &c. 

 (London : C. Kegan Paul and Co., 1878.) 



'E have before us a very striking instance of the 

 value of a popular knowledge of mechanical 

 philosophy. 

 The book is essentially divided into two parts. The 

 rst six chapters contain a history of the steam-engine 

 a machine ; while Chapters vii. and viii. are devoted 

 to the philosophy of tUe steam-engine, its history, and- 

 f^pplication. 



As regards the first part we have but little to say. In 

 htwo points this part of the book is distincdy commend- 

 iable; the author gives ample reference to the numerous 

 sources from which he has derived his information, and 

 he has cast aside all national partiality. The literature 

 of the history of the steam-engine is now so considerable 

 that it can have been no small task to condense an abstract 

 into something less than the limits of a small volume and 

 at the same time make it interesting ; and the success 

 which has been attained must be largely attributed to the 

 excellent illustrations. Much of the matter has doubtless 

 come ready to the author's hand, requiring but little 

 modification. In places the style of the author very 

 closely resembles that of Mr. Smiles. The plan adopted 

 is that of awarding unlimited praise to the various in- 

 ventors instead of distinguishing between their various 

 claims. Throughout this part of the book httle or no 

 attempt is made to explain the physical questions involved 

 or to record the steps by which a knowledge of the 

 physical properties of steam has been acquired. 



Had, however, the first six chapters constituted the 

 book, it must have been allowed to pass as a fairly full 

 and very interesting account of the development and 

 application of the mechanism of the steam-engine ; much 

 in the same style as the work of Dr. Lardner but in 

 many respects much better and containing considerably 

 more matter. 



The history of the philosophy of the steam-engine con- 

 tained in Chapter vii. might also be allowed to pass, 

 although the assurance with which commendations are 

 distributed to such men as Camot, Joule, Mayer, Rankine, 

 Regnault, and Thomson could only have been justified by 

 evidence of the possession on the part of the author of a very 

 unusual appreciation of the highest theory of his subject — 

 an appreciation for which the earlier part of the work had in 

 no way prepared us, and which is certainly not shown by 

 the merit of the author's comments in this chapter. 

 These comments, however, are of the most cursor)' kind, 

 and although for the most part imintelligible, they did 

 not prepare us for the disclosiu-e of the last chapter, in 

 which we have the author's own exposition of the philo- 

 sophy of the steam engine and its application. 



A suspicion that the author's physics are not what they 

 should be began to dawn upon us when we came to the 

 paragraph in which he describes the essentials of a good 

 Vol. XIX. — No. 4^7 



furnace, which suspicion was strengthened at the follow- 

 ing sentence — "A pound of carbon has been found to be 

 capable of liberating by its perfect combustion resulting 

 in the formation of carbonic oxide 14,500 British thermal 

 units — " but we still reserved our judgment, as carbonic 

 oxide might be a misprint for carbonic acid. However, 

 on turning over the page we find the following erroneous 

 deduction : — 



"The laws of thermo-dynamics teach, as has been 

 stated, that the proportion of the heat-energy contained 

 in the steam or other working fluid which may be trans- 



formed into mechanical energy is a fraction, — t-— — \ of 



Hi 

 the total, in which H^ and Hg are the quantities of heat 

 contained in the steam at the beginning and at the end of 

 its operation, measuring from the absolute zero of heat 

 motion. In perfect gases, 



Hi — Hg _ Ti - T2 ^ Tx - Tg , 



H, 



Ti-f 461-2° Fahr. ' 



but in imperfect gases, and especially in vapours which, 

 like steam, condense, or otherwise change their physical 



state, this equality does not exist, and — L^ — ^ > ILJIT2 ; 



Hi r^ 



and the fluid is more efficient than the perfect gas as a 

 working substance in a heat-engine. In any case it is 

 seen that the efficiency is greatest when the whole of the 

 heat is received at the maximum and rejected at the 

 minimum attainable temperatures." 



This paragraph shows how completely the author has 

 misapprehended the second law of thermo-djmamics. 

 And this is not nearly all ; the theory of the steam-engine 

 is not so simple but that a slip of this sort might have 

 been pardoned, but when we come to the author' s appU- 

 cation of the theory to the deduction of the economy of the 

 " possible engine of the future," we have page after page 

 of perfect nonsense, which not only shows that the author 

 does not understand what he is writing about, but also 

 shows that his erroneous views of, and imperfect ac- 

 quaintance with, the theory of the steam-engine have led 

 him into absurd errors from which the earlier inventors 

 on whose work he has so boldly pronounced had emanci- 

 pated themselves. How far this is the case will appear 

 from the following quotations : — 



" Heat-engines may be divided, for present purposes, 

 into three principal classes, according to their disposition 

 of rejected heat : 



" I. Those which restore all heat rejected from the 

 working cylinder to the reservoir' from which it was 

 derived. 



" II. Those which restore a part of the unutUised heat 

 of the working fluid, discharging the remainder from the 

 system and allowing it to be wasted. 



"III. Those which waste all heat rejected from the 

 working cylinder. 



" N o existing type of steam-engine belongs to the first 

 of the classes specified. Some forms of air and gas- 

 engines are theoretically assignable to that class, as, by 

 means of some form of ' regenerator,' they store up re- 

 jected heat and restore it to the succeeding charge of 

 working fluid as it enters the cylinder. . . . 



" There are two forms of engines of Class I., in which 

 — were it possible to fully avail ourselves of them — all 

 this waste of energy may be avoided : 



"Type A. The working fluid, if expanded from the 

 temperature and pressure of the boiler or reservoir quite 

 down to the absolute zero, would have all its heat-energ\- 

 transformed into mechanical work, and there would be 

 no waste. The efficiency would be perfect. 



s 



