274 



Free Path Phenomena 



[CH. xiv 



From some experiments of Loschrnidt, treated in this way, the values 

 of coefficients of interdiffusivity of four gases can be calculated. The follow- 

 ing table is taken from Kelvin's Baltimore Lectures (p. 295). 



Gases 



H 2 (1) 

 2 -(2) 

 CO (3) 

 C0 2 -(4) 



/ Pairs of Gases 3) u 



(12, 13, 23) 1-32 



(12, 14, 24) 1-35 



(13, 14, 34) 1-26 



Mean 1-31 



Pairs of Gases 35 22 



(12, 13, 23) -193 



(12, 14, 24) 190 



(23, 24, 34) 183 



Mean 189 



Pairs of Gases 3) 33 



(12, 13, 23) 169 



(13, 14, 34) 175 



(23, 24, 34) 178 



Mean 174 



Pairs of Gases 3)44 



(12, 14, 24) 106 



(13, 14, 34) Ill 



(23, 24, 34) 109 



Mean 109 



The agreement inter se of the values obtained by a set of three gases 

 gives in itself a striking confirmation of the theory. 



Let us, however, carry our test further by comparing the values of the 

 coefficients of interdiffusivity just found with those given by equation (640). 

 In the following table, the first column gives K, the mean of the values given 

 in the table of p. 251, the second column gives p, the third gives the value of 2) 

 calculated from equation (640), and the fourth gives the value of 2) calculated 

 from Loschmidt's experiments. 



The mean of the entries in the last column is 1*41 which is in excellent 

 agreement with the theoretical T34 ; and, as previously occurred in the 

 similar case of heat-conduction, we shall see that the small discrepancy is 

 such as could be attributed to intermolecular forces. 



