( 490 ) 



phase A from a solution by rapid precipitation at (lie temperature of 

 the room, and that in isolated drops! A few other phytosterol esters 

 exhibit analogous phenomena which I will describe later on in a 

 more elaborate communication on these substances. 



§ 10. A very remarkable fact in the n-valerate, the iso-valerate 

 and the isobutyrate, is the differentiation of the isotropous fusion into 

 a large number of globular, doubly-refracting liquid drops of con- 

 siderable dimensions, which like the circles of fat on soup float 

 alongside and over each other and often unite to multiplets, whose 

 separate parts are still recognisable. Wreathed aggregations of the 

 liquid globules are also observed occasionally. In most cases the 

 separate liquid globules exhibit the black cross and the four luminous 

 quadrants grouped centrically. They are, however, also seen to roll 

 about frequently, so that the projection of the optical symmetry axis 

 now 7 takes place excentrically. Owing to the enormous size of the 

 individuals and the low temperature-limits, these esters lend them- 

 selves to the study of these phenomena certainly Vorlander's p- 

 azoxybenzoic-ethy Jester. 



If the temperature of the mass, when totally differentiated into 

 liquid globules — and the isobutyrate is particularly adapted for this 

 differentiation — is slightly raised, the liquid globules are often seen 

 to disappear suddenly just after they have enlarged their limits as it 

 were by an expansion. It is like a soap-bubble bursting by over 

 blowing. 



§ 11. Finally, I wish to observe that the thermical transitions 

 just described and particularly those of the two valerates, can only 

 be interpreted by assuming a quite continuous progressive change. 

 For all these gradual transformations, either on melting or on soli- 

 difying, a measurable time is required and nowhere is to be found 

 any indication of a sudden leap. An exception is, however, afforded 

 by the sudden crystallisation of the two butyrates. 



§12. As regards the differentiation of the fusion L into an 

 aggregate of anisotropous liquid globules, I will now make a com- 

 munication as to an experiment upon the crystallising of ferric 

 chloride hexahydrate, which substance exhibits something similar, and 

 which, like most undercooled fusions and like many compounds 

 which exhibit liquid crystals, crystallises in typical spherolites. 



If we melt the compound Fe, Cl 6 -j- 12 H,0 cautiously in a little 

 tube, taking care that no water escapes, and a drop of this brownish- 



