ON THE STATISTICAL VIEW OF NATURE. 595 



credit of having first indicated, and to Prof. Boltzmann 1 

 aided by many other eminent natural philosophers 

 that of having definitely established, this highly 

 suggestive explanation or illustration. The doctrine 

 of chances, to which artifice the statistical view of 



(p. 139). "The conception of the 

 ' sorting demon ' is merely mechan- 

 ical, and is of great value in purely 

 physical science. It was not in- 

 vented to help us to deal with 

 questions regarding the influence 

 of life and mind on the motions 

 of matter, questions essentially be- 

 yond the range of mere dynamics" 

 (p. 141). The other contribution 

 through which Clerk - Maxwell's 

 name has become celebrated in this 

 connection is to be found in the 

 so-called Maxwell-Boltzmann law of 

 the distribution of kinetic energy 

 in a mass of moving particles. 

 The discussion of the subject 

 dates from the first memoir of 

 Clerk-Maxwell, quoted above ; and, 

 after Prof. Boltzmann had treated 

 of the same subject in 1868, 

 and Mr Watson in 1876, Clerk- 

 Maxwell returned to it in a paper 

 " On Energy in a System of 

 Material Points" (' Camb. Phil. 

 Soc.,' vol. xii.) In the year 1894 

 Prof. Bryan presented the 2nd 

 part of his Report on "Our 

 Knowledge of Thermodynamics " 

 ('Brit. Assoc. Rep.,' 1894, p. 64, 

 &c.), in which he gives an account 

 of all the different investigations 

 referring to this subject, up to 

 that date. This was followed by 

 a long discussion of the subject 

 in the pages of ' Nature ' (vol. li. ), 

 in which Messrs Bryan, Boltzmann. 

 Burbury, Culverwell, Larmor, and 

 H. W. Watson took part, and 

 which gave Prof. Boltzmann the 

 opportunity of giving a final ex- 

 pression of his opinion (p. 415). 



1 Prof. Boltzmann's investiga- 

 tions connected with the second 



law of thermodynamics and the 

 kinetic theory of gases cover the 

 last thirty - five years. He has 

 succeeded in putting the whole 

 problem more and more into a 

 strictly accurate, as also into a 

 popularly intelligible, form. Un- 

 fortunately his very numerous con- 

 tributions are scattered in various 

 periodical publications, and have 

 not yet appeared in a collected 

 edition. Most of them appeared 

 in the Proceedings and Transac- 

 tions of the Vienna Academy, 

 among which the Address delivered 

 on the 29th May 1886 can be 

 specially recommended. Since then, 

 and after the correspondence in 

 ' Nature ' referred to in the 

 last note, he has published his 

 lectures ' Vorlesungen uber Gas- 

 Theorie ' (2 vols., Leipzig, 1896-98). 

 He there (vol. ii. p. 260, note) 

 gives a list of the most important 

 literature on the subject, and also 

 a general summary regarding the 

 application of the theory of prob- 

 abilities to the distribution of the 

 kinetic energy of a crowd of 

 moving particles. In this con- 

 nection he also deals with the 

 consequences of the atomic hy- 

 pothesis, the irreversibility of all 

 natural processes, and the applica- 

 tion of the second law to the 

 history of the universe. He there 

 says (p. 253) : " The fact that 

 the closed system of a finite 

 number of molecules, if it had 

 originally an orderly condition, and 

 has then lapsed into a disorderly 

 one, must finally, after the lapse 

 of an inconceivably long period, 

 assume again orderly conditions, is 



