346 



EXPERIMENTS ON DIFFUSION IN RELATION TO 



or the H--**"^> between the centres of the molecules at collision is proportional 

 to the quantity <r, which may be deduced from experiment. 

 If <*, and </, are the diameters of the two molecules, 



Henoe if d = a ...... <r u = *(8, + 8,) ........................... (4). 



Now M. Loachmidt has determined D for the six pairs of gases which 

 can be formed from Hydrogen, Oxygen, Carbonic Oxide, and Carbonic Acid. The 

 MX values of <r deduced from these experiments ought not to be independent, 

 since they may be deduced from the four values of 8 belonging to the two 

 Accordingly we find, by assuming 



TABLE I. 



8(H) =1-739 

 S(O) =2-283 

 8 (CO) =2-461 

 8 (CO.) = 2-775 



Note. These numbers must be multiplied by % 6 to reduce them to (centi- 

 metre-second) measure from the (metre-hour) measure employed by Loschmidt. 



The agreement of these numbers furnishes, I think, evidence of considerable 

 strength in favour of this form of the kinetic theory, and if it should be 

 confirmed by the comparison of results obtained from a greater number of pairs 

 of gases it will be greatly strengthened. 



Evidence, however, of a higher order may be furnished by a comparison 

 between the results of experiments of entirely different kinds, as for instance, 

 the coefficients of diffusion and those of viscosity. If p. denotes the coefficient 



