Heat of Mixture of Substances. 589 



to infinity may be divided into two parts — the work done 

 against the attraction of the same kind of molecules in the 

 mixture, and that done against the attraction o£ the other 

 kind of molecules. The first part may be written 



where 



Bl= KS'T7 1 ) 



if the relative distribution of the molecules 1 in the mixture 

 is expressed in terms of the distance of separation of the 

 molecules in the pure liquid 1. The way the functions B^ 

 B 2 , and others of the same nature are formed will appear at 

 once from a study of the way the functions A] and A 2 are 

 formed which is given in the paper quoted above. The 

 other part is obtained by substituting- the law of attraction 

 between two different molecules given at the beginning of 

 the paper for <p(z)(% V^i) 2 in the equation for the internal 

 latent heat of evaporation given (pp. 793-802) in a previous 

 paper quoted above. If the relative distribution of the 

 molecule 1 with respect to the molecules 2 is expressed in 

 terms of the distance of separation of the molecules 1 in the 

 pure liquid, this gives for the work done 



where 



In a similar manner it can be shown that the work done in 

 removing a molecule 2 from the liquid to infinity is 



2 N 2 



where 

 and 



