( 569 ) 
In order to enter into more details, we must first examine what 
is the form of p as a function of the quantity o. 
IV. Let us to this purpose state the fact, that p represents the 
excess of the thermodynamic potential in the bordering layer above 
that in the mercury and the solution. Therefore we may write in 
any case; 
p=(ptaeawutfo?+...)4+Aologe, 
where c represents the concentration of the SO,- or Cl-ions in the 
bordering layer, or — when the sign of A is reversed — that of 
++ 
the Hg-ions. The constant A may have the positive, as well as the 
negative sign. When the charge spreads in such a way, that it 
penetrates rather deeply into the bordering layer — as the experiments 
++ 
seem to prove for the case that the Hg,-ions form the + charge (the 
mercury being negative) — then A will be positive. So this is the 
case for the descending branch of the electro-capillary-curve. But 
when the charge remains more at the surface of the bordering 
layer, as is the case, when SO,- or Cl-ions form the negative charge 
in the solution (the mercury being positive), then A is negative. 
We find this realised in the ascending branch of the curve. 
Writing aw for ¢c, we get: 
ost =(ao+28e?+...)+ Aw logan + Ao, 
a) 
and equation (3) takes the following form: 
¥=%— Ao—(k+ fw)... . . . (4) 
This is the accurate equation of the electro-capillary-curve, and 
in what follows we will determine the value of po, A and & +4 
‚for the two parts of the curve — on the left and on the right of 
the point, where @ = 0, 
The maximum is obviously to be found in one of the branches, 
when 
1) @ is in this equation still a function of the concentration of the electrolyte, as 
appears from the experiments of Smira. See i.a. OsrwarLp, Lehrbuch I, 531 ff. 3 
Ever, Z. f. Ph, Ch. 28, 625 (1899); 39, 564 (1902). 
