696 RICE 



ART. L 



inactive cations into, the electrolyte layer, so that the depression 

 of 0- below the "normally" depressed value due to the charge 

 grows less ; the actual curve gets nearer to the ideal. Even when 

 the exact neutralization of charge is just attained there are still 

 some anions ui the layer, balanced as regards charge by cations 

 and, with no charge on the mercury surface, still exerting some 

 depressing effect. At the maximum, the specifically adsorbed 

 anions have nearly disappeared from the layer, so that there are 

 practically only inactive cations with a corresponding negative 

 charge on the mercury, producing a normal depressing effect 

 on the surface tension with a very small specific anionic effect; 

 presently all the anions will have left the layer of solution and 

 thereafter the effect is normal; the curve merges with the ideal 

 curve. It would appear that at the maximum the surface of the 

 mercury should not be uncharged but should have a small 

 negative charge and the electrolyte should be a little above the 

 mercury in potential. 



Certain solutions exhibit an opposite effect, producing a 

 curve practically normal to begin with, but falling below the 

 ideal as E increases. This could obviously be accounted for by 

 a hypothesis of active cations with inactive anions. Also 

 there are solutions for which the curve rises like the normal 

 curve, then falls under it and later on merges into the ideal 

 curve once more on its descending branch. 



Certain deductions from this view have been verified. Thus, 

 for a solution involving only inactive ions, the P.D. between 

 it and mercury in the natural state should equal the value of 

 Em', hence if a cell were constructed with mercury electrodes in 

 two such solutions, its E.M.F. should be the difference of the 

 observed values of each Em. This has been found to be so. 

 Also, if we were to make a cell with mercury electrodes and two 

 solutions each of which involves active anions, we should find 

 that its E.M.F. is equal to the difference between the values 

 of E for the same surface tension provided this value of the 

 tension falls on the normal parts of the graphs in their final 

 descending portions; for at such a stage the specific effect of 

 adsorbed ions has disappeared and only the "purely electric" 

 effect is remaining. This has also been found to be true. 



