88 Dr. R. D. Kleeinan : Determinations of the Law of 



Differences. It will represent the whole curve A/" A 2 " f 

 with a degree of closeness depending on the extent of the 



Fig. 4. 



/< 



part of the curve represented by experiment. On the above 

 supposition we could thus approximately determine the law 

 of molecular attraction. But if we are not able to prova 

 that the attraction is independent of the temperature the 

 law deduced should involve an arbitrary function. The 

 above result is, however, of importance, as it will enable us 

 later to determine whether the attraction is a function of the 

 temperature or not. 



We have then ihat an infinite number of formulae for the 

 surface tension or latent heat of a liquid can be obtained, 

 each of which corresponds to a law of molecular attraction, 

 and that we cannot be sure without further evidence whether 

 any one of the laws happens to be the true law. All these 

 laws are included in the general law that can be deduced 

 which contains an arbitrary function. It is owing to this 

 fact that different investigators of molecular attraction have 

 obtained different results, and in some cases results have 

 been deduced concerning the potential energy of a molecule 

 and the origin and nature of its attractive forces which are 

 quite absurd. 



