048 



Prof. J. P. Kucnen on tlie 



e. Hexane and Methyl-alcoliol. 

 The hexane was used as it was obtained from Kahlbaum. 

 The phenomena in this case were similar to those observed 

 with pentane. The existence of an upper critical temperature 

 was ah-eadv known *. The following Table Y. shows the 

 effect of pressure on the critical point of the liquids. There 

 is a linear relation between temperature and pressure, as far 

 as the accuracy of the experiments allow^s one to judge. 



Table Y.— Hexane and Methyl-alcohol. 

 Critical points of liquids. 



Temp. 



Press. 



Temp. 



Press, 



37-0 







41-4 



143 



37-9 



33 



42-4 



175 



38-6 



55 



1 42-6 



182 



39-4 



81 



43-8 



228 



40-25 



105 



44-8 



264 



413 



141 







Above 37° C. there is a maximum vapour-pressure, as 

 shown by the boiling-point. The mixtures also have the 

 jjroperfy of a minimum in the (ordinary) critical tempera- 

 ture (Table YL); for a full discussion of the connexion between 

 these two phenomena, viz. maximum vapour-pressure and 

 minimum critical temperature, we refer to former papers f. 



Table YI. — Hexane and Methyl-alcohol. 

 Critical points. 



1 



1 



Hexane (S. Youug) ... 



Methyl-alcobol 



i Mixture 



Temp, i Press. 



234-8 

 241-2 

 210-2 



29-6 

 80 

 56-0 





f. Hexane and Ethyl-alcoJiol. 



An upper critical point w^as found at —65° C, below Avhich 

 two layers are possible. This point is thus very much lower 

 than for methyl-alcohol. The influence of the alcohol on 

 the critical point was further investigated with carbon 

 di sulphide. 



* Kotlimund, Zeitsch. Physik, Cheviie, xxvi. p. 455. He found the 

 critical point to lie at 42°-6 C.; but the hexane used by him was probably 

 puror than mine. 



t Kuenen, Phil. Mag-, (h) roL xl. p, 173. vol, xliv, p, 174. 



