304 



phase, and in all cases loilhout exception the first branch falls 

 luith increase of temperature more rapidly than the second. The 

 result is thus just opposite (o what we should expect if we founded 

 our opinion on the mentioned hypotheses about the molecular state 

 of the two liquid phases; and with regard to the great probal)ilit_v of 

 the correctness of these views, the fact observed may be considered 

 as a rather strong argument against the opinion, tliat it is right 



oft 



to consider the smaller or greater values of — as a somewhat sure 



ot 



criterion for the judgment of the degree of an occurring dissociation 

 in tiie liquids. 



It will be remarked further that tlic mutual position of the two 

 brandies of the curve always indicates a sadden increase of the 

 value of n at the transformation from the anisotropous-liquiil into 

 the isotropous-liquid condition. This discontinuity does not set in 

 precisely at tiie transition-temperature: from the observations it 

 seems rather probable, that it occurs in a continuous way, and 

 already starts at temperatures below the transition-temperature. 



In that case the two branches could perhaps be linked together in 

 the way indicated in the diagrams by dotted lines (tig. 1). 



Now although in the cases of both ethers t/uo branches were also 

 present in the ^i-t-curves (tig. 2j, and here too ii seems to increase 

 suddenly at the transformation into the isotropous-liquid state, another 

 remarkable peculiarity reveals itself here in so far, as the values of 

 fi for the isotropous-liquid phase fall in the beginning with increase 

 of temperature and then increase again to a flatter or steeper maxi- 

 mum in tlie curve. It can hardly be doubted that these phenomena 

 are real ones; in these isotropons liquids we were therefore forced 

 to see the first instances of liquids, whose free surface-energy 

 increases with a rise of temperature. The explanation of such an 

 abnormal phenomenon must be found in the algebraic sign of the 

 lieat-efTect which accompanies the eventually isothermical enlarge- 

 ment of the surface-layer of the liquid. What peculiarities of the 

 molecular structure of these isotropous liquids could be the cause 

 of such abnormal heat-effect, is for the moment incomprehensible 

 and very difficult to imagine. In any case the said phenomena 

 indicate the presence of molecular conditions in these liquids, 

 differing of course very much from those, which are intrinsic for 

 most of the common isotropous liquids. 



Laboratory for Inoryanic and Physical 

 dheniistry of the University. 

 Groninyen, June 1915. 



