THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



FEBRUARY 1888. 



XL On some Questions in the Kinetic Theory of Gases. 

 By Prof. Ludwig Boltzmann*. 



§ 1. On Avogadro's Law and the Coefficient of Friction. 



IN my former papers on the heat-equilibrium of a mixture 

 of two gases, I have nowhere made mention of the phy- 

 sically less important case when the molecules of one of the 

 mixed gases come into collision among themselves compara- 

 tively seldom, or when the number (N x ) of molecules in the 

 unit volume is greatly smaller for the one gas than the number 

 (N 2 ) for the other. 



In reference to this, Prof. Tait, in his first paper on this 

 subject in the Transactions of the Royal Society of Edin- 

 burgh f, on page 78, reckons the following amongst the 

 necessary assumptions for the proof of Boyle's law : — " That 

 there is perfectly free access for collision between each pair of 

 particles, whether of the same or of different systems ; and 

 that, in the mixture the number of particles of one kind is 

 not overwhelmingly greater than that of the other kind;" and 

 adds to it the remark : — " This is one of the essential points 

 which seem to be wholly ignored by Boltzmann and his com- 

 mentators. There is no proof given by them that one system, 

 while regulating by its internal collisions the distribution of 

 energy among its own members, can also by impacts regulate 

 the distribution of energy among the members of another 



* Translated, at the request of the Author, from advance proof-sheets 

 from the Sitz. der Kais. Akad. der Wissensch. Wien, Bd. xcvi. 



t Tait, Phil. Trans. Edinb. vol. xxxiii. part i. p. 65 (1886); in abstract 

 in Phil. Mag. vol. xxi. (1886) p. 343. 



Phil. Mag. S. 5. Vol. 25. No. 153. Feb. 1888. G 



