672 



Chemistry. — ''The metastahle continuation of the mixed crystal 

 series of pseudo-components in connection loith the phenomenon 

 allotropf. II. By Prof. A. Smits. (Communicated by Prof. 

 J. D. VAN DER Waals). 



(Communicated in the meeting of Sept. 26, 1914). 



In the first communication on this subject ') different possible 

 continuations of the mixed crystal series in the raetastable region 

 have been discussed, in which chiefly the mixed crystal phases 

 coexisting with liquid were considered. 



The metastable continuation of the coexistence of two mixed crystal 

 phases was only mentioned in a single case, where namely continuity 

 of the mixed crystal phases in the metastable region was supposed. 

 It is now, however, the question what can be said of this 

 coexistence for the case that the said continuity does not exist. We 

 consider, therefore, one of the figures from 7 to 12 inclusive from 

 the previous communication, and ask what can be predicted about 

 the metastable continuation of the lines j) and m. 



On the whole a transgression of the melting temperature without' 

 melting setting in, or in other words supersolidification, is considered 

 possible also on slow rise of temperature. The continuity discussed 

 by Van der Waals between the sublimation line a b and the melting 



point line i^ c of a single sub- 

 stance, see fig. 1, starts from 

 this supposition ; we shall, there- 

 fore, also here have to take the 

 possibility into account that the 

 melting fails to appear at the 

 eutectic temperature, and that 

 the coexistence continues to exist 

 between the two mixed crystal 

 phases. It is, however, the ques- 

 tion w^hether this possibility is 

 limited. It follows from the con- 

 tinuity between the sublimation 

 line and the melting-point line 

 pj j^ considered by van der Waals that 



such a limit has been assumed 

 for the coexistence between solid -|- vapour and solid -{• liquid. 



1) These Proc. XVI p. 1167. 



