414 

 TABLE 2. 



the three-phase vapour as rarefied gases. If this is the case, it may 

 he derived from the laws of the rarefied gases by a tliermodynamie 

 \va> that the three-phase pressure is necessarily smaller than the 

 sum of the vapour tensions of the two components. For the proof 

 we refer to the second part of the Thermodynamik of Van dkr 

 Waals-Kohnstamm (p. 476). The conclusions stated there: "Denn der 

 Partiaidruck einer Komponente in einer absolut stabilen Phase kann 

 niemals grosser sein als der Sattigungsdruck der reinen Komponente" 

 and "Fur alle absolut stabilen Phasen ist also der Partiaidruck 

 kleiner als der Sattigungsdruck ; audi wenn der Dreiphasendruck 

 höhei' liegt als die beiden Sattigungsdrucke, wird er also dennoch 

 immer kleiner sein als die Summe dieser beiden Tensionen" refer 

 therefore only to equilibria of real gasphases, i e. gases, which do 

 not possess an a])preciable surface tension, (f, however, the gas 

 phases dei)art from the rarefied gas laws, so if the phases have 

 surface layers, the (piantities a, a., and a.^^ resp. e^, è^, and possibly 

 also Aj.^ play a part, and the above-mentioned proof is no longer valid. 



7. It appears from the detei-minations of § 3 that the water- 

 content of the liquids rich in hexane increases pretty considerably 

 on ap|)roach to the critical end})oint. Though it was not indispensable 

 for the purpose of this investigation to know the concentration of 

 the liquids rich in water of the three-phase equilibrium, I have yet 

 carried out some experiments with a view of getting to know these 

 concentrations. It then appeared that the quantity of hexane occurring 

 in the liquids rich in water, is particularly small. With a mixture 

 of Ü.06 mol. perc. of hexane it was still possible for me to follow 

 the three-phase line throughout the inv^estigated temperature range. 

 The hexane content of the water-layer is therefore decidedly smaller 

 than 0.06 mol. perc. 



