392 Prof. G-. "N. Antonoff on Interfacial 



considerable change of the surface tension. If, moreover, 

 one or both of the components are volatile at the tempera- 

 ture of the experiment, as in the case of water- benzene and 

 water-chloroform, it is almost impossible to obtain the right 

 value of surface tension for the aqueous layer. This can be 

 demonstrated by the following table : — 



Table II. 



Layer with higher 

 surface tension. 



Layer with smaller 

 surface tension. 



Solu- 

 bility. 



a 2 . 



da 2 

 dc 



15 7o 



22-7 



nearly 



4-5 



40-0 



•4 



4-2 



21-1 



•55 



1-2 



26'6 



•3 



•1 



28-2 



nearly 



t ,„„ Solu- da. 



Liquids. ,.,., a,. — 1. 



bihty. i dc 



Isobutyric alcohol- water ... 5*4% 23"9 9'4 



Aniline-water 3'2 44D 10 



Water-isoamylic alcohol ... 2*6 25*7 19 



Chloroform-water -8 54'0 24 



Benzene-water -1 6O0 100 



It is obvious from the above that in the case of almost 

 immiscible liquids the experiment is unable to settle the 

 question definitely. 



For the same reason the so-called Gibbs-KonovalofFs law 

 cannot be proved for immiscible liquids. Konovaloff *, who 

 first, succeeded in proving the law experimentally, could only 

 show qualitatively that in the system water-carbon disulphide 

 the aqueous layer gives off vapours containing very much 

 more carbon disulphide than was to be expected as the result 

 of small solubility in water. All the same, that law proved 

 experimentally for miscible liquids is generally accepted and 

 is believed to be true for all pairs of liquids forming two 

 layers, however small their mutual solubility may be. This 

 law is an essential condition of equilibrium, so that it is 

 bound to be extended over nearly immiscible pairs. 



For the same reasons I believe also the relation 



«12 = «1 — a 2 



to be a general law. 



It can only be deduced theoretically if a definite assump- 

 tion be made with regard to the molecular construction of 

 the solutions. The equality of molecular concentration in 



* Konovaloff's law : — Two equal layers in equilibrium have equal 

 vapour pressure and equal composition of vapour. 



