12 



AKT. 10. — K. IKEDA : STUDIES ON THE 



for straight vapour pressure curves. Yet Zawidzki has found 

 the mixture of benzene and carbon tetrachloride to have such 

 curves. If the idea of chemical similarity could be applied to 

 such cases, it would be too indefinite to be of much value as a 

 criterion. Yet there seems to be some truth in Young's assertion, 

 because chemically allied substances mix with one another mostly 

 without much change of energy or of vokime. 



In a ternary system the vapour pressures, total as well as 

 partial, are represented by planes 

 as shown in Fig. 2, while the 

 surface of the total pressure has 

 the form of a sail sp>read between 

 three points, when the composi- 

 tion is that of the gas phase. 

 The plain and the curved sur- 

 faces of the total pressure are 

 represented by the following ^= 

 equations : 



F F, "^ Fo "^ P^ 



where C\', GJ, CÎ/ are the molar 

 fractious of the components in the gas phase, and Pj, Pi, P^ are 

 the vapour pressures of the pure components at the given tem- 

 perature. 



It is quite clear that these equations can be extended and 

 applied to the ideal system of any number of components. 



There seem to be some solid solutions whose vapour pressure 



