:in4 



homogeneous pliase(.s) are in internal equilibrium, the system beliaves 

 as a unary substance, i.e. as a substance of" one component. 



When we consider the behaviour of' the two modifications with 

 a solvent, we have a pseudo ternary system, which becomes binary 

 when the different kinds of molecules assume iulernal ccpiilil)iium 

 in the homogeneous phases. 



To set fortli tiie cases discussed by Dimroth in the most easily 

 comprehensible way, I will follow the method whicli I discussed 

 ali'eady before in the publication: "Das Gesetz der Umwaudlungs- 

 stufen OsTWALüs im Lichte dei' Theorie der Allotropie" '). 



Kig. 1. 



At the angles of the equilateral triangle Fig. 1 the letters A, B, 

 and C' are placed, of which A and B represent the pseudo-compo- 

 nents, which are miscible in the solid state to a limited degree, C 

 denoting the solvent. 



In this triangle have been given among others the solubility 

 isotherm of the mixed crystal series AA^ represented by the curve 



I) Z. f. phys. Ghein. 84, 385 (1913). 



