ON ELECTROLYSIS.

By H. SCHUCHT.


Concerning the separations which take place at the positive pole, the
composition of the peroxides, and the manner of their determination,
relatively little has been done.

If solutions of the salts of lead, thallium, silver, bismuth, nickel,
and cobalt are decomposed by the current between platinum electrodes,
metal is deposited at the negative, and oxide at the positive
electrode. Manganese is precipitated only as peroxide. The formation
of peroxide is, of course, effected by the ozone found in the
electrolytic oxygen at the positive pole; the oxide existing in
solution is brought to a higher degree of oxidation, and is separated
out. Its formation may be decreased or entirely prevented by the
addition of readily oxidizible bodies, such as organic acids, lactose,
glycerine, and preferably by an excess of oxalic acid; but only until
the organic matter is transformed into carbonic acid. In this manner
Classen separates other metals from manganese in order to prevent the
saline solutions from being retained by the peroxide.

With solutions of silver, bismuth, nickel, and cobalt, it is often
practicable to prevent the separation of oxide by giving the current a
greater resistance--increasing the distance between the electrodes.

The proportion between the quantities of metal and of peroxide
deposited is not constant, and even if we disregard the concentration