Application of the Kinetic Theory of Gases. 



77 



" On the Application of the Kinetic Theory of Gases to the Electric, 

 Magnetic, and Optical Properties of Diatomic Gases." By 

 George W. Walker, B.A., A.B.C.Sc, Fellow of Trinity 

 College, Cambridge, Sir Isaac Newton Besearch Student. 

 Communicated by Professor Bucker, Sec. B.S. Beceived 

 January 23, — Bead February 14, 1901. 



(Abstract.) 



The aim of this paper is to apply the method of " The Boltzmann- 

 Maxwell Kinetic Theory of Gases " to the electric, magnetic, and 

 optical properties of gases. For the sake of simplicity the molecule is 

 supposed to consist of two atoms, so that the results apply to gases 

 such as Hydrogen or Oxygen. Several of the results indicate, however, 

 qualitatively what we might expect for more complex molecules. 



One of the atoms is supposed to have a positive electric charge and 

 the other an equal negative charge, and the force in play between the 

 two atoms is taken as the ordinary electrostatic force. 



It is contended that the molecules may be classified into three 

 types — (1) that in which the two atoms rotate in contact ; (2) that in 

 which the two atoms revolve in elliptic orbits about their C.G., but not 

 in contact ; (3) that in which the two atoms move in hyperbolic 

 orbits for the short time during which they influence each other 

 appreciably. They may thus be regarded as practically free. 



The first portion of the paper is concerned with calculations respect- 

 ing the relative proportions of these three sets ; and although a quite 

 complete solution is not obtained, the results indicate certain important 

 features, and may prepare the way for a more complete investigation. 



It is next shown that such a system will exhibit magnetic properties, 

 and the coefficient of magnetic susceptibility is calculated. The formula 

 obtained shows a close agreement with Professor Quincke's experiments 

 on this question. 



The system will also exhibit electrical properties. The dielectric 

 constant is calculated. The formula differs essentially from other 

 theories of electric susceptibility, e.g., Boltzmann's, in the important 

 dependence on temperature. A note at the end of the paper, giving some 

 recent experimental results by Herr Karl Baedecker, shows how 

 closely the theory agrees with his experimental observations of the 

 temperature effect. 



The electrical conductivity is calculated as depending on the number 

 of free atoms present. Beference is also made to a paper by the 

 author, communicated to the Physical Society of London, in which it 

 is shown how the formation of striae in a vacuum tube may be 

 accounted for. 



