other, the reaction between solid F, liquid m and gas m, is in thes 
two cases also different. 
Fig. 9. Fig. 10. 
On reducing the pressure still further, the two regions LG and 
FG separate and diagrams as in Fig. 10 are obtained. The non- 
a drawn saturation line of F represents metastable 
mconditions only; solutions saturated with F can, 
, therefore, occur only in the metastable condition 
v 6 at this pressure. 
M Le The case is, however, different with the vapours 
ee 4 saturated with F; these all occur in the stable 
Fig. 11, condition and are represented by the closed vapour 
saturation line of Fig. 10. 
By a further fall in pressure this vapour saturation line of F 
becomes continuously smaller; at the vapour pressure of the com- 
pound F it contracts to a point, namely point F, and on further 
reduction in pressure it disappears. 
Hence, the liquid as well as the vapour of the system F + L + G 
again trace a closed curve (Fig. 11). Mamb is the saturation 
line of F under its own pressure, M, a, m, b, its conjugated vapour 
line. On the one curve the pressure in M is maximum and in m 
minimum, on tbe other curve in M, and m,; the pressure thus 
increases in both in the direction of the arrows. 
The two Figs. 7 and 11 exhibit a great resemblance to each 
other; yet they differ in different respects such as for instance, in 
the situation of the points F, m and m, in regard to each other. 
This causes that in Fig. 7 the point F is situated outside and in 
Fig. 11 within the vapour line. 
When deducing the previous diagrams we have assumed that on 
change of pressure, the liquidline of the heterogeneous region moves 
more rapidly than the saturation line of F or what amounts to the 
same that the vapour line of the heterogeneous region I. G moves 
quicker than the vapour saturation line of F. 
