of maximum-pressure occur. [Compare this figure with fig. 1 in 
Communication XV on “Equilibria in ternary systems’ |. The satu- 
ration-curves under their own vapour-pressure of Z, have, therefore, 
their point of maximum-pressure on the line GZ, Consequently on 
curve AA the pressure has to increase in the direction of the little 
arrows and it must be a maximum in /. The same applies to the 
other curves of the region Z, LG. On curve cu, however, no maximum 
of pressure occurs; this is metastable here. As it must, however, be 
situated on the line GZ,, it follows that the pressure has to increase 
from w towards c. 
In the region Z,LG the curves must have their point of maximum- 
pressure on the line GZ,, in the region Z,LG on the line GZ, ; 
hence it follows that the pressure increases along the curves in the 
direction of the arrows. 
Let us consider now the region Z,LG. At a change of 7’ and P 
in fig. 1 the phases Z, and G remain unchanged in place, the 
solution LZ however traces the region between the curves Laand Lb. 
Triangle Z,LG may, therefore, have its angle-point 4 sometimes 
on the one side, sometimes on the other side of the line GZ, and 
casually on this line. 
In the P,7-diagram (fig. 2) this same region is situated between 
the curves sa and 74; in fig. 3 this region is drawn once more with 
its limiting curves (Z) = tb and (Z,) =. We take in this figure 
a point m on ib and on { a point d corresponding with the points 
(4,) 
yy 
m and d of fig. 1. As Tag—T;, in fig. 3 the line dm must be 
parallel to the P-axis. The same applies to the line ab, when a and 
