1382 
With a current density 2.56 no scattering takes place in n.H,SO,. 
If however, sodium sulphate is added till the solution is also normal 
with regard to this, we find with the same density of current a 
scattering of 0.3. 
The influence of the sodium = sulphate is now easily explained 
when we assume the formation of a sodium alloy, but not when 
we consider the scattering as a consequence of the primary hydrogen 
generation. 
Besides the formation of a sodium alloy, there will also have to 
take place a primary hydrogen generation, which does not cause 
scattering. According to the experiments by Haser and Sack men- 
tioned in the introduction alloys of lead with more than 8°/, of 
sodium react forcibly with water. We shall, therefore, have to assume 
that in the electrolysis no alloys will be formed with a greater Na- 
content, for before the Na-content has increased so much, the alloy 
will already have reacted with water. An alloy with 8°/, Na contains 
about 2.5 aeg. Pb to 1 aeg. Na, hence when exclusively this alloy 
was formed in case of electrolysis, we should have to find about 
2.5 for the scattering power of lead in sodium salts. 
The highest value which was found, is 1.7, and from this follows 
that in electrolysis partly Na-ions are discharged, partly H-ions, in 
which accordingly a primary hydrogen generation takes place with- 
out cathode seattering. With smaller current density and higher 
temperature the scattering power diminishes, i.e. the primary hydro- 
gen generation increases, the formation of the sodium alloy becomes 
slighter. This is in good harmony with the fact that for smaller 
current density and higher temperature the overvoltage for hydrogen 
generation at a lead cathode decreases. It is different with the 
nerease of the scattering on increasing dilution of the salt solution. 
In a solution of Na,CO, the concentration of the Na-ions becomes 
smaller on increased dilution, that of the H-ions becomes greater. 
The primary generation of hydrogen would therefore have to be 
promoted at the expense of the discharge of the Na-ions. Of this a 
slighter scattering would have to be the consequence. A stronger 
scattering is, however, observed. An explanation of this contradiction 
is not to be given without further hypotheses. 
For solutions of sodium salts and likewise of potassium salts, the 
cathode scattering can for the greater part be accounted for by the 
assumption of the formation of a sodium- resp. potassium alloy ; for 
the scattering in sulphuric acid, however, another cause must be 
sought. Here the hydrogen is primarily developed ; if this generation 
takes place at the boundary surface lead-sulphurie acid there is no 
