1348 
At a temperature t,, below that of the transition point under the 
vapour pressure B, the P,X-section is as indicated in Fig. 10. At 
this constant temperature and variable pressure the unary system 
exhibits the phenomenon of monotropy. Sy, is the stable moditication 
under the vapour pressure. At a temperature above that of the point 
B, e.g. t,, enantiotropy is found on increase of pressure, as Fig. 11 
shows. Under the vapour pressure 5,, is now stable. At the higher 
temperature t,, above the metastable triple point D’ and below the 
stable triple point D, everything remains more or less the same, 
only when we want to represent the metastable internal equilibria 
in the unary figure, the drawing becomes somewhat more intricate, 
ID 
Sr SPE 
