THE KINETIC THEORY OF GASES. 



347 



of viscosity, and p the density of a gas at 0C. and 760 mm. B., the theory 

 gives 



J^^'i < 5 >' 



so that the following relation exists between the viscosities of two gases and 

 their coefficient of interdiffusion 



ft p. 



(6). 



Calculating from the data of Table L, the viscosities of the gases, and com- 

 paring them with those found by 0. E. Meyer and by myself, and reducing all 

 to centimetre, gramme, second measure, and 0C. 



TABLE II. 

 Coefficient of Viscosity. 



The numbers given by Meyer are greater than those derived from Loschmidt. 

 Mine, on the other hand, are much smaller. I think, however, that of the 

 three, Loschmidt's are to be preferred as an estimate of the absolute value 

 of the quantities, while those of Meyer, derived from Graham's experiments, 

 may possibly give the ratios of the viscosities of different gases more correctly. 

 Loschmidt has also given the coefficients of interdiffusion of four other pairs 

 of gases, but as each of these contains a gas not contained in any other pair, 

 I have made no use of them. 



In the form of the theory as developed by Clausius, an important part 

 is played by a quantity called the mean length of the uninterrupted path of a 



442 



