NATURE 



477 



THURSDAY, MARCH 24, 1S81 



MACQUORN RANKINE'S SCIENTIFIC 

 PAPERS 

 Miscellaneous Scientific Papers by W. J. Macqiwrn Ran- 

 kine, C.E; LL.D., F.R.S., late Regius Professor of 

 Civil Engineering and Mechanics in the University of 

 Glasgow. From the Transactions and Proceedings 

 of the Royal and other Scientific and Philosophical 

 Societies and the Scientific Journals. With a Memoir 

 of the Author by P. G. Tait, M.A., Professor of Natural 

 Philosophy in the University of Edinburgh. Edited by 

 W. J. Millar, C.E., Secretary to the Institute of Ship- 

 builders in Scotland. With Portrait, Plates, and Dia- 

 grams. (London : Charles Griffin and Co., 1881.) 

 THE volume before us contains thirty-seven papers of 

 rare scientific interest written by the late Prof. 

 Rankine, who died now eight years ago. As to the cause 

 of this long interval the Editor gives us no hint, nor is 

 there anything in the volume to explain it. All the papers 

 are reprints, without note or comment, except such as is 

 contained in the concise but extremely graceful Memoir. 

 These papers are not by any means all Rankine's original 

 works. They are principally those relating to Thermo- 

 dynamics and Hydrodynamics. There are however tvvo 

 important papers on the latter subject which are not con- 

 tained in the volume ("On Stream Lines," Philosophical 

 Magizine, 1865; "On the Mathecal Theory of Stream 

 Lines," Phil. Trans. Royal Society, 1871). These can 

 hardly have been omitted by design, as in the very last 

 paper contained in the volume the author resumes the 

 subject, directing attention to his paper of 1865, while 

 the paper of 187 1 is the most general and important paper 

 Rankine wrote on this subject, besides being his last 

 work. 



The first twenty-seven papers contain the development 

 by Rankine of that most modern of mathematical sciences. 

 Thermodynamics, from its foundation-stone to the com- 

 plete edifice as it exists at the present day. This by no 

 means constitutes Rankine's entire work, nor do we think 

 it his most useful work. But it is the largest gem in the 

 casket, and should he be forgotten in all the rest this 

 alone will secure for him a foremost place amongst those 

 who have left their mark on philosophy. 



The rapidity of the development of this branch of 

 science is unrivalled. As profound as anything ever 

 brought to light by the power of reason, it only occupied 

 Rankine four years from the publication of his first paper 

 until the theory was completed and apphed to all cases. 

 That the burning of coal was necessary to the production 

 of steam, which was necessary for the working of an 

 engine, and that the proportion of coal burnt bore some 

 relation to the work done, were facts which for 200 years 

 had been forcing themselves into notice, and gradually 

 there had come to be an idea that in some way heat was 

 the same thing as other forms of mechanical energy. 

 But this was all, till, in 1843, Dr. Joule published his first 

 experimental determination of the mechanical equivalent 

 of heat. Published in an obscure way, it was some years 

 before this novel but definite relation between heat and 

 energy excited notice. The first published notice is by 

 Thomson in 1849, although that Rankine had known it 

 Vol. xxiii. — No. 595 



for some time previously is shown by the first of these 

 papers, published in July of that year. In December of 

 the same year Rankine sent in the Papers III. and XIV. 1 

 containing the elements and some applications of his 

 theory, and in 1854 he had published the complete theory 

 and its applications to various engines, making instant 

 use of the splendid experimental results just then obtained 

 by Regnault. From this time it has been as possible 

 definitely to forecast the result to be expected from any 

 kind of engine as from 1690 to predict the behaviour of 

 the moon. 



From a philosophical point of view, there was a keen 

 race in discovery between Thomson, Rankine, and Clau- 

 sius, a race in which Thomson had the start, but which 

 was neck and neck between Rankine and Clausius. But 

 from the practical point of view Rankine was alone. And 

 in this respect these papers, as indeed all his others, have 

 a value both intrinsic and as examples of method which 

 even transcends their philosophical value. 



It was Rankine's practical knowledge which gave him 

 his great advantage, but he had in some respects an ad- 

 vantage in having based his theory by means of an hypo- 

 thesis on the fundamental laws of motion. Rankine 

 worked from an hypothesis of his own creation as to the 

 molecular constitution of matter, which was perfectly 

 definite and capable of including all the phenomena which 

 he had to consider. The definiteness of his hypotheses 

 gave that definite form to his formula which suggested 

 many points otherwise overlooked. 



But as often happens, the definiteness of his hypotheses 

 was also his source of weakness ; he assumed the atoms 

 of matter to be masses of fluid subject to eddies and 

 vibrations, but otherwise at rest. This suited the condi- 

 tions of his problem, but it was only an hypothesis, and as 

 it was definite, so any phenomenon with which it was in- 

 compatible sufficed to disprove the hypothesis and bring 

 down the edifice raised upon it. And such phenomena, 

 those of diffusion, existed ; although they did not come 

 within the range of his work. 



Rankine was himself fully alive to his position, and 

 having once obtained his ideas and framed his formute 

 took and acknowledged a hint from his contemporaries, 

 Thomson and Clausius ; and having shown that Carnofs 

 theorem, which they had modified and made the basis of 

 their reasoning, was a consequence of his molecular vor- 

 tices, he adopted a general law as the base of his 

 reasoning, and cut himself off from his hypotheses. This 

 was easy for him to do, for, as may be seen in § 15^ of 

 Paper III., he had with no small care framed his hypo- 

 theses so as to fit the same law, though expressed in other 

 words. This article is also interesting as showing the 

 unlimited faith he must have reposed in the design and 

 care of Providence. Not only does he conceive each atom 

 of matter to possess a fluid atmosphere, in which exist a 

 number of similar cyclones or eddies, symmetrically 

 placed all over the atom, but he required that wherever 

 two atoms touched there two eddies should face, and so 

 exactly as to be coaxial. Many complicated properties 

 were attributed by Newton and others to the corpuscles 

 of light, but such a demand as is here implied on the 

 attention of Providence has probably never been equalled 



* Why this paper is placed so far out of its chronological order does not 

 appear. 



