84 
the course of the phenomenon, thirdly the zero-line, fourthly a line 
that corresponds to a definite potential difference, and finally time- 
lines given by a signalling apparatus. 
Thus in our experiments with iron in ‘/, N. ferro-sulphate solation 
the following photograplis were obtained. 
The line DE represents the potential of iron I with respect to 
iron Il before the anodic polarisation. The other two horizontal lines, 
which run all over the figure, are the zero-line and the line for 
—90 milli Volt. The curve A BC represents the phenomenon observed 
after anodic polarisation of iron | with a density of current of + 
0.360 Amp/cm.’. 
The iron electrode I is at first disturbed in noble direction after 
this anodic polarisation, but this disturbance ceases with great 
rapidity and the potential descends to a value which is about 90 
milli Volt. more negative than the potential before the anodic 
polarisation. The iron keeps this negative potential only for a short 
Kg Ï } Ï i ES, j ; ' et : mn eer 
Fe 
Fig:2.- 
time, and rises, first with increasing, then with decreasing rapidity 
to the value observed before the anodic polarisation. 
In fig. 2 the phenomenon has been photographed that was observed 
when instead of a solution of ferro-sulphate, a solution of '/,, N. 
ferro-chloride was used. In a few words we may remind here 
that the increase of concentration in the boundary layer through 
the short anodie solution has brought about a slight change of the 
potential in positive direction. In order to find out in how far the 
found phenomenon is something particular that is caused by the 
anodic polarisation of iron, also the course of the potential of the iron 
was photographed after cathodic polarisation. This photo is repro- 
duced in fig. 3, we see that the iron after cathodic polarisation 
with a density of current of + 0.360 Amp/em.’. is still pretty 
greatly disturbed in base direction, the potential of the iron was, 
namely, in this experiment at first about 80 milli Volt. more negative 
than before the cathodic polarisation, which potential difference had, 
