1581 
E550, = 0.01 ny. f= 152: 
Current density. 
Duration of the 
electrolysis 0.08 0.16 0.32 
10 sec. 1.9 1.9 
30 sec. — lized eZ 
90 sec. 1.2 14 1.6 
On greater concentration of the sulphuric acid the scattering 
becomes smaller. Thus we found for a current density of 2.56 and 
a duration of the electrolysis of LO sec. : 
Concentration of the sulphuric acid 
Online 0.2 n. OS nn. O.4 n. O.5 n. 
Aes, 0.8 0.3 0.1 0.0 
7. Discussion of the results. 
It has appeared from the above that both in alkalic and in neu- 
tral and acid solution lead seatters cathodically when the current 
density exceeds a certain value. It seems therefore possible that in 
all these cases the scattering will be the consequence of a primary 
generation of hydrogen, also in solutions of sodium salts so that 
it would not be necessary to assume here the formation of a sodium 
alloy which seatters through the action of the water. 
Yet there are reasons to assume that the lead scattering in solu- 
tions of Na and K salts is, indeed, caused by the formation of an 
alloy of these metals with lead. In the first place the fact that no 
appreciable scattering takes place in calcium salts. [f it were always 
the consequence of a primary generation of hydrogen, it would not 
be possible to understand why this primary generation of hydrogen 
does not give rise to scattering in a calcium solution, whereas it 
does so in a sodium or potassium solution. If on the other hand it 
is assumed that in a solution of a calcium salt primary caleium is 
deposited which reacts with water before it has appreciably pene- 
trated into the lead, this accounts for the difference between calcium 
and sodium salts. That a caleium salt is not able to prevent the 
scattering by some action or other, as e.g. a chromate does, follows 
from this that in a mixture of a calcium and a potassium salt 
scattering does take place. 
The following experiment proves further that the scattering in 
solutions of sodium salts has another cause than in acid solutions. 
SIE 
