Theory of Electrocapillanty. 375 



When mercury comes in contact with the solution, ions of 

 mercury will enter the solution if 6 < 0, although their osmotic 

 pressure may be greater than tlie ionic solution pressure of 

 mercury; if e>0, they will be removed from the solution, 

 their osmotic pressure may thereby be less than the ionic 

 solution pressure. Thus we see that, whilst the value of the 

 potential difference between the solution and the mercury is 

 determined only by the osmotic pressure of ions of mercury, 

 contrary to Nernst's theory the direction of the reaction 



which takes place when a new surface is formed, depends on 

 the sign of e, and therefore on all active components of the 

 solution. 



Also, contrary to Nernst's theory, the existence of a 

 potential difference between solution and mercury is not at, 

 all connected with the exchange of ions of mercury. In 

 fact, if the concentration of the ions of mercury corresponds 

 to the zero value of e, no ions at all are exchanged when a 

 new surface is formed ; the potential difference which we 

 must assume between solution and mercury to account for 

 the displacement of the maximum can be caused only by 

 adsorbed layers of anions and cations : we are justified in 

 calling it adsorption potential difference. 



In conclusion, I gladly take this opportunity of expressing 

 my gratitude to Professor A. Sakhanow for the interest he 

 has taken in the progress of this work. 



Laboratory of Physical Chemistry, 

 The University, Odessa. 



XLIII. On the Theory of Electrocapillarity \ II. 

 By Alexander Frumkin *. 



AS Gibbs has stated, there exists a simple relation between 

 the adsorbed quantity of a substance and the lowering- 

 effect on the surface-tension, expressed by the equation 



r=- — ^ a) 



where T is the excess of the solute in gram-inols. per cm. 2 

 of the dividing surface, c the concentration of the solute, 

 and 7 the surface-tension. 



* Communicated bv the Author. 



