870 
The regions, in which Z, Z and A occur as solid phases, are 
indicated by eircumeireled letters. 
Pre yi. Fig. 2 
It appears from the direction of the little arrow on curve hi 
(fig. 1) that the vapour-pressure is higher in / than in / This 
saturation-curve 47 is represented in fig. 2 by a straight line h7 
parallel to the P-axis, the point / is situated, therefore, higher than 
the point 7, so that curve 7 hd must be situated above curve mid. 
Curve «6 of fig. 1 is represented in fig. 2 by the straight line 
ab parallel to the P-axis; as, in accordance with fig. 1, the pressure 
is higher in a than in 4, in fig. 2 point « must be situated above 
point 4 and consequently curve da above curve in b. 
We have drawn in fig. 2 curve mb starting from m towards 
higher pressures, later on we shall see that this need not be always 
the case. 
Now we have still to determine in fig. 2 the position of curve 
(Z) with respect to the other curves. We are able to do this in 
different ways, we shall show that the metastable prolongation mx 
of curve 77m Is situated below curve i h. 
For this we imagine in fig. 1 the curves gh and 7 to be pro- 
longed till they intersect one another in a point w. This point of 
intersection is a point of the metastable prolongation of curve 7m. 
As T= Ti= lj Ti the 2 points “zah,* g and: ate shut 
fig. 2 on a straight line parallel to the P-axis. It is apparent from 
fig. 1 that the vapour-pressure is smaller in point . than in / and 
in 4; in fig. 2 the point w is situated, therefore, below point 7, so 
that curve me is situated below curve mb. 
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