( 207 ) 



5, I have represented in (Ig. 7 tlie ligiire into wliicli tig-. 4 is 

 changed when vi <[ v^. 



We see then, that something peenliar appears i.e. a continuous 

 closed solubility isotherm Gecfi\i\, which contracts more and more 

 with rise of temperature, and disappears from the stable region at 

 the maximnm three phase pressure. 



When the lower three phase pressure line Cj e^ s^ has ascended to 

 é?i'Ci', or in other words, when we consider the temperature of the 

 point F', the solubility isotherm has assumed the shape indicated by 

 the line e^e^^' c^'f^c^. At this temperature the ?«m«mi/??i of the solubility 

 isotherm, which was still in the stable region before, gets into the 

 'metastable region. If we raise the temperature np to the melting 

 point of AB or to the temperature of the point F, the former phe- 

 nomenon is repeated with respect to the maximum, which just below 

 this temperatnre was still to be found in the stable region. Accordingly 

 at still higher temperature no maximum or minimum occurs in 

 the portions of the solubility-isotherm passing through the stable 

 region, and we only retain the lines c^c\ and e^e'^. These lines 

 become smaller and smaller with rise of temperature, and the two 

 three phase pressure lines e^ e^ and e\ c\ approach each other more 

 and more, till the^^ have coincided at the maximum three phase 

 temperature in ESC. The branches of the solubility isotherm touch 

 at this temperature exactly in the points E and C. With further rise 

 of temperature they retreat altogether to the metastable and unstable 

 region, after which they disappear^). 



In the case that vi ]> Vg solid AB can still coexist with liquid 

 above the maximum three phase temperature, viz. under higher 

 pressure, but this is not the case when vi<^Vs, which also follows 

 already from the figs. Sa and Sb. 



We see further that in fig. 8 two three phase lines occur with a 

 maximnm temperature, in fig. 9 only one, and in fig. 10 three. 



Fig. 9 shows, that the case 2, where the vapour tension of the 

 combination is smaller than that of the components, is certainly the 

 most interesting case, as it can yield a three phase line with a 

 minimnm and two maxima, which had been unknown np to now. 



As to the situation of the two branches of this peculiar three 

 phase line we may still remark that only one of the possible cases 

 is drawn here. These branches may pass through each other or 

 partially coincide, but this does not make any essential difference. 



Remarkable complications present themselves, when it is assumed 



1) Later on Ihope to discuss the course of ihe solubility isotherm in the meta- 

 stable and unstable regions between the temperatures of F' and .F more in details. 



