CHEMICAL THEORY OF SOLUTIONS. PART I. 71 



solution, as the study of vapour pressure at a constant tem- 

 perature. 



{c) The Eq^dlibrium between Liquid and 

 Solid Phases. 



It has been shown by Beckmann in his well known cryo- 

 scopic studies that the depression of the freezing point caused 

 by associated substances such as alcohol in solutions in normal 

 liquids, as for instance benzene, is sometimes far less than might 

 be expected. This has been further confirmed by the investiga- 

 tions of various savants and particularly by those of Auwers 

 and his pupils. J. Schroeder (Zeits. physik. Chem., 11, 449 ; 

 1893) has shown tliat the fusion curve of a normal substance 

 deviates considerably from the ideal course, when the other 

 component is associated, and indeed in the sense expected. 



In the cases in which the conditions of quasi-ideal solutions 

 are satisfied, the equations of the fusion curves can be readily 

 obtained as shown in the sequel. 



(1) The Solid is the Normal Component. 



Since equation (7) must hold in this case, we have by (35) 



R 



(i--^) 



or l~x=-^ 1-— (52) 



where T^ is the melting point of the normal substance. Were 

 both components normal. 



