367 
changes in such a way that the minimum point Z, gets higher than 
L,, so that a change of stability takes place. Under these circum- 
stances we get what I discussed before for the solid phase. At the 
moment that the minimum points lie at the same height, the unary 
liquid phase will suddenly be changed into one of different concen- 
tration, if no retardation takes place. 
So in this case we have enantiotropy for a liquid or a liquid 
with a point of transition. 
The (7,7)p-fig. of the pseudo-binary and unary system can then 
have the form as indicated in fig. 6, when the equilibria with solid 
substance are omitted. 
We see from this that the two stable unary liquid lines £Z, and 
£,k, are continuously connected with each other by a partially 
metastable, partially unstable middle portion, and that in accordance 
with the theory of allotropy the equilibrium between the two phases 
L, and L, is perfectly comparable with the equilibrium between 
two solid phases at the temperature of transition. 
If we now examine what may happen when the region of incom- 
