Josiah Willard Gibbs. 287 



indeed, seems to have been less directed toward the development of 

 the subject in extension than toward the nature of the molecular 

 phenomena of which the laws of thermodynamics are the sensible 

 expression. He seems to have very early felt the conviction that 

 behind the second law of thermodynamics, which relates to the heat 

 absorbed or given out by a body, and therefore capable of direct 

 measurement, there was another law of similar form, but relating to 

 the quantities of heat (i.e., molecular vis viva), absorbed in the perform- 

 ance of work, external or internal." [The laws of partition of 

 molecular energy are then compared with Clausius' hypothesis of the 

 Disgregation ; cf. his 9th Memoir, 14.] 



In its second stage, with which Gibbs is fundamentally associated, 

 the science of thermodynamics widened out into the tracing of the 

 consequences of applying the Carnot-Thomson-Clausius principle of 

 dissipation to natural changes of all kinds : only such changes will be 

 spontaneously possible as do not involve, so to speak, negative or 

 reversed dissipation. From the beginning, the question of the range 

 of the validity of this principle attracted attention. 



Lord Kelvin, in his earliest exposition of the " Dissipation of 

 Energy" (April, 1852) already feels justified in the assertion that 

 " restoration of energy is probably never effected by means of organised 

 matter, either endowed with vegetable life or subjected to the will of 

 an animated creature." At a much later date (1882) Helmholtz still 

 considers it an open question whether such a possibility could arise 

 in the very delicate arrangements of the animal organisation. 

 Nowadays, probably, the presumption would be in favour of Lord 

 Kelvin's view ; violation of it would, in fact, necessitate the recognition 

 of " vital force " in a very unambiguous and conspicuous form. 



The cosmical results of the dissipation of energy mainly occupied 

 Thomson's attention; he k has nowhere, any more than Clausius, 

 essayed the development of the theory into a doctrine of chemical 

 and physical statics of matter in bulk. The first to emphasize in 

 general terms, by aid of examples, the rich possibilities in this field, 

 was Lord Rayleigh, in 1875, in a lecture on " The Dissipation of 

 Energy."* Later in the same year he made the first quantitative 

 application in this direction, by calculating the dissipation intrinsically 

 involved in the mixture of different gases, j This discussion revealed 

 various clues towards general procedure. The idea of reversible 

 chemical absorption of one of the gases (of carbonic acid for example 

 by quicklime) at once solves the main question proposed, though it is 



* "Roy. Inst. Proc.," 1875; "Scientific Papers," i., p. 238. [Horstmann's 

 applications of the principle of maximum entropy (1873) should also be mentioned.] 

 f " Phil Mag.," xlix., 1875, p. 311 ; loc. cit., i., p. 242. 



