a 
883 
Solution containing 0.06 grammol. Fe(NO3)3 per litre. 
Temp. of the solution | Condition of the iron 
go ie active 
3° | passive 
Be | passive 
Ao passive 
limit 8°— 9° 
Toe active 
se passive 
3. Though the possibility of the here observed phenomenon had 
been predicted on the ground of our views, more experiments had 
to be made before we could see a firm confirmation of the said 
considerations in the results obtained. E 
It is namely known that Fe(NO,), is partially hydrolytically split 
up; henee it had to be examined if the disturbing influence. could 
possibly have been exerted by the mtrie acid present in the solution used. 
To ascertain this the experiment was repeated at room temperature 
with a solution of nitric acid, which was a slightly stronger acid 
than the ferri-nitrate solution used. The result was that the iron 
remained active. To make the result still more pronounced the nitric 
acid concentration was increased to 32°/, by weight of HNO,, but 
the result did not change, the iron remained active. 
This indubious result showed therefore that the disturbing action 
of the ferri-nitrate solution with regard to iron is really owing to 
the ferri-ion, and that the obtained results may be accepted as con- 
vineing confirmations of the newer views about the electromotive 
processes and equilibria between a metal and an electrolyte. 
SUMMARY. 
Through the above described investigation it has therefore been 
proved with certainty that, in perfect agreement with the supposition 
pronounced already before, the disturbance in the iron surface by 
a solution of ferri-nitrate must be attributed to this that the unary 
iron can be in eleetro-motive equilibrium only with a solution which 
contains only exceedingly few ferri-ions by the side of ferro-ions, 
so that iron put in a ferri-solution will emit ferro-ions and electrons. 
