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On cooling, the following phenomena occur: At about 200° the 

 isotropous liquid becomes turbid, at 198° the doublj-refracting mass 

 attains its greatest viscosity; at 196" it has already become thinner, 

 but now at about 198^ it again becomes thicker and the whole 

 appearance of the phase is strikingly altered, although still remaining 

 doubly refracting. It then seems to pass gradually into the green 

 and red coloured, doubly refracting liquid phase, which, if we prevent 

 the undercooling by inoculation, solidifies at 155°. 8. 



If the solid substance is melted under Lehmann's crystallisation- 

 microscope, — where the conditions of experimenting are naturally 

 quite others than before, — it seems, that but one liquid phase, the 

 green and red coloured, is continually changed into the isotropous 

 one: no sudden changing is observed. On cooling, the aspect of the 

 anisotropous phase now obtained, is quite different from the first 

 mentioned. 



I also think I must come to the conclusion that the liquid 

 phase (^ = about 190") occurring on cooling is perhaps only the 

 passage to the other three, so that here, three stable liquid phases 

 might occur. It is very remarkable that the transitions of the 

 two stable anisotropous phases into the intermediate one appear, 

 when we work carefully, quite continuous; the viscosity appears 

 to pass gradually into that of the more stable phases. Remarkable 

 also is the impossibility to find the temperatures of transition 

 exactly the same on the rising, or falling, temperature of the 

 external bath. The values obtained for the initial and final tempe- 

 rature of each phase-traject vary within narrow limits. The same 

 is the case when, on melting the solid substance, one wishes 

 to determine the point where the first softening of the mass takes 

 place ; in the determination of the temperature, intervals such as from 

 147° to 156° are noticed. The progressive change of the cooling of 

 isotropous-liquid to solid resembles here in a high degree a process 

 where a continuous transition exists between the different stadia. It 

 is as if the labile phase is composed of an entire series of condi- 

 tions which occur successively to form the connection on one side 

 between anisotropous and isotropous-liquid. The whole shows much 

 resemblance to a gradual dissociation and association between more 

 or less complicated molecule-complexes. It is quite possible that 

 the transitions solid-liquid occur really continuously instead of 

 suddenly, in which case an uninterrupted series of labile inter- 

 mediate conditions — which cannot be realised in most substan- 

 ces — are passed, some of which intermediate conditions might 

 be occasionally fixed in those substances which like these cliole- 



