Z AKT. 11. — T. YAMAMOTO : THE FUSION CURVES 



conditions are the unchangeability of total volume and total 

 energy on mixing the components at constant temperature and 

 pressure. 



In those cases, in which one or more of the components 

 are associated, the relations fonnd are more complicated. But 

 it is quite probable that some of them at least become amenable 

 to theoretical treatment when various chemical species actually 

 present in the solution are taken into consideration. The energy- 

 and volume-changes which occur on mixing the components in 

 such cases may be attributed to chemical changes. Chemical 

 combination may take place between different components, and 

 the degree of association may be decreased by the act of mixing. 



Suppose, for the sake of argument, that the solution has 

 reached the state of chemical equilibrium. Let the chemical 

 changes, which the component chemical species may undergo, be 

 arrested by tlie addition of appropriate negative catalysers. The 

 chemical species can now be separated and again mixed together 

 without causing any appreciable volume- or energy-changes, for 

 no chemical change takes place. The presence or absence of the 

 catalysers will make no difference in the chemical potential of 

 the various chemical species, which must then conform to the 

 equation (1). The removal of the catalysers will not cause any 

 change in the state of equilibrium. When the equation holds 

 strictly, then the mixture is what has been called a quasi-ideal 

 solution by Prof. Ikeda. 1'he present study is undertaken to 

 furnish an instance of such a solution. 



The usual methods of chemical analysis do not enable us to 

 distinguish between various chemical species when the velocity 

 of their mutual transformation is not very small. Hence what 

 we call a chemical substance may not be chemically quite uni- 



