768 



substance F, represented by pq [we leave the curve r.s', (Ji-avvn in 

 the figure out of consideration for the present]. 



Fig. 1. 



Iji the same way as we liave acted in the general case [tig. 11 (l)J 

 or in tlie peculiar case (XI), we may deduce also now the different 

 diagrams. 



T<^ Tf. At tirst we take a temperature 7' lower than the 

 minimummeltingpoint 7V of the binary compound F. Now we find 

 a diagram just as tig. 2 for the satui-ationcurxe under its own vapour- 

 pressure of F and the corresponding straight vapour-line. In this 

 figure, in which the component-triangle is only partly drawn, hgn 

 is the saturationcurve under its own vapourpressure ; we find the 

 corresponding straight vapour line Cg^ on side CA. 



When we assume, as is supposed at the deduction of fig. 2, that 

 neither a point of maximuni-pr-essure, nor a point of minimum- 

 pressure occurs, the pressure increases from n towards A; conse- 

 quently it is lowest in n and highest in It, without being, howevei', 

 a minimum in n or a maximum in h. It follows from the deduction 

 that the sides solid-gas and solid-liquid of the threephasetriangles 

 must be situated with respect to one another and to the side CB 

 just as is drawn in fig. 2. 



It is apparent from the figure that the binary liquids Jl and n can 

 be in equilibrium witli the unary vapoui- C and that the ternary 

 liquids a, c and /; can be in equilibrium with the binary vapours 

 öTi. Cl and h^. It is apparent that somewhere between the liquids c 

 and b a liquid g must be situated, the corresponding vapour g^ of 

 which represents the extreme point of the straight vapour line Cg^ . 



When a liquid follows curve hn. first from k towards (/ and after- 

 wards IVom g towards n, the corresponding vapour ^/i follows conse- 



