386 Prof. G. N. Antonoff on Interfacial 



The origin of this theory is due to Gibbs * and Thomson f, 

 who have applied it to gaseous mixtures, but its detailed 

 development in the application to solutions is due to 

 Freundlich J, Milner §, Lewis ||, and others. 



On the basis of the theory of Gibbs and Thomson, 

 Freundlich and Lewis have given the formula 



c da 



where u is the excess of the mass of dissolved body, expressed 

 in grams per square cm. of the surface, c = concentration of 

 the dissolved body in the depth of the solution, B,= gas 

 constant, T = absolute temperature, a = surf ace tension, 



— = change of surface tension with the concentration of 



dc 



the dissolved substance. 



It is usual to apply the term " adsorption " to this change 

 of concentration at the surface of a liquid. Let us consider 

 some consequences of applying this formula to the critical 

 points of solutions. We have seen that for a whole series of 



concentrations, -^-=0. and therefore we should also have 

 dc 



w = 0. 



In other words, with the increase of concentration the new 

 substance introduced distributes itself in the interior of the 

 liquid and does not enrich the surface layer. 



But Lewis.% in order to verify this formula, has made 

 some researches on the subject and arrived at results which 

 do not agree with the theory. 



With the experimental results of Lewis as a basis, 

 Arrhenius** has been led to conclude that the phenomena 

 of absorption are not in simple dependence on those of 

 capillarity, and all attempts to relate these phenomena 

 directly are, in his opinion, doomed to failure. However, 



* Thermod. Studien, p. 271. 



t .T. J. Thomson, 'Applications of Dynamics to Phys. & Chem.' p. 191. 

 X Kapillarchemie, p. 50. 

 § Phil. Mag-. [6] xiii. p. 96 (1907). 

 ,| Lewis, Phil. Mag. [6] xvii. p. 466 (1909). 

 H Ibid. 



** Meddelanden f. K. Vetenskapakademiens Nobelinstitut, Band 2 f 

 No. 7 (1911). 



