1542 
and curve Le the saturationline of Z, + Z, under its own vapour- 
pressure. As long as those curves de not come too close to the 
triangle Z, Z, Z,, the vapour-pressure of those equilibria increases 
with the temperature; we shall assume this also here. 
Zomi-------42 
VENS se \ % 
Fig. 2 
The P,7-diagram is drawn in fig. 2; we may deduce it easily 
in different ways. Of course it satisfies also the rule of the diagonal 
order of succession. The phases form viz. in fig. 1 a monoconcave 
quintangle [as in fig. 3 (1/)] with the sides GZ, 4,2, 7,4, ZL 
and LG. When we trace this quintangle in diagonal direction, then 
we find the same order of succession as the curves in fig. 2. 
