1578 
the determinations inter se does not amount to more than 5°/,, so 
that we may assume the mean to be accurate up to 2—8°/,, except 
for the small current densities, where the deviations are greater. 
Besides it appears from them that even for these determinations of 
short duration the power of scattering in many cases decreases in 
course of the experiment. The table further shows that with great 
current density the scattering power approaches a limiting value 
of about 1.7. 
Other sodium salts, sodium hydroxide and sodium sulphate yield 
very much the same value for A except for small current density, 
when the determinations are uncertain. In figure 2 the value of A 
has been drawn as function of the current density for normal 
solutions of Na,CO,.Na,SO,, and NaOH, at 15°. 
A : 
As on electrolysis NaOH is formed on the cathode, the solutions 
of Na,CO, and Na,SO, at the cathode are to be considered as 
mixtures of NaOH with Na,CO,, resp. Na,SO,. 
4. Influence of the concentration and the temperature of the solu- 
tion on the power of scattering. 
The power of scattering increases with decreasing concentration, 
as appears from the subjoined table, which applies to a current 
density of 0,32 ampere per em.? and 15°. 
Normality Na,CO, 
2 1 0.5 0.25 0.125 
A 1.28 1.41 1.46 1.50 1.52 
Likewise for decreasing temperature. For a normal solution of 
Na,CO, we found with D=0,16: 
