-( 551 J 
selves of invariable molecules — so which do not associate to moré 
complicate atom-groups. 
For a binary mixture I have (Cont. II p. 101) derived the diffe- 
rential-equation for the relation between v, x and 7. We shall be able 
to find in the same way the differential equation for the relation 
between v,2,y and 7’, 
For coexistence of two phases of a ternary system, distinguishing 
the phases by the indices 1 and 2, the following equations must be 
EE 
Eelt) 
GG). 
se op dw 
in which — represents i etc. 
dv dv zyT 
If the concentration for the first phasis is given, and so z, and 
yi, then the quantities v,9,y¥, and vz are determined by the four 
above equations, and so the properties of the coexisting phasis. But 
in order to caiculate them all the equations would have to be known, 
for which the knowledge of the equation of state is required. Even 
if we make use of them, the intricacy of these forms does not admit 
of the solution of the unknown quantities. Results, however, can be 
derived from the differential equation, even if we do not know these 
quantities accurately, and these results are not without interest. In 
the same way as is followed in Cont. I page 102 for a binary 
mixture, we find for a ternary system : 
