( 764 ) 
Besides, however, by deposition of different solid substances the 
complexity of a liquid phase can also be shown in another way, 
and investigations in this direction have led to the result that it 
may be considered as the rule that the liquid phase of a substance 
is built up of different kinds of molecules (ions included). 
Bancroft *) and Bakhuis Roozeboom * 2 ) have pointed out that when 
a substance behaves as a unary substance, this is accounted for by 
the fact that the setting in of inner equilibrium takes place so 
rapidly in the homogeneous phase that the inner equilibrium if 
disturbed, is immediately restored by the appearance or disappearance 
ot a new phase; the melting-point, boiling-point, critical-point etc. 
of a substance which behaves as a unary one, does not relate then 
to a single kind of molecules, but to an equilibrium between different 
kinds of molecules. 
Bancroft’s pupils, viz. Carveth, Soch, and Cameron*) have inves¬ 
tigated different tautomeric substances; it then appeared that it may 
be pretty easily shown in some cases that under certain circumstances 
the existence of two kinds of molecules in the liquid phase may 
lead to a binary behaviour, for when the liquid cooled rapidly, the 
inner equilibrium could not follow the temperature, and the mass 
solidified at a temperature which differed from the unary stable 
melting-point, for then a point was realized of one of the melting- 
point lines of the pseudo-binary system A -\- B, which for the 
examined substances always showed a eutectic point. 
As is evident we find the unary stable melting-point where the 
curve for the inner liquid-equilibrium meets one of the melting-point 
curves of the pseudo-binary system. 
Now it is remarkable, as I already wrote, that nobody has observed! 
what surprising results are arrived at when it is assumed, what is 
undoubtedly true, that not only mixed crystals are always formed 
in a greater or less degree, but that moreover the inner equilibrium/! 
which exists in the liquid phase, continues to exist in the solid 
phase. 
Starting from this supposition we get the relation between hetero-i 
geneous and homogeneous allotropy, indicated in Fig. 1, from which 
it appears that the phenomenon of enantiotropy means unmixing | 
m the solid state, which phenomenon appears when the curves for 
*) Journ. Phys. Chem. 2, 143 (189$). 
2) Zeitschr. f. phys. Chem. 28, 289, (1899). 
3 > Journ. Phys. Chem. 2, 159 (1898). 
ibid. 2, 364 (1898). 
ibid. 2, 409 
