_only single electro-chemical equivalents of elementary ions can go to
the electrodes, and not multiples_.

831. vi. A body not decomposable when alone, as boracic acid, is not
directly decomposable by the electric current when in combination (780.).
It may act as an _ion_ going wholly to the _anode_ or _cathode_, but does
not yield up its elements, except occasionally by a secondary action.
Perhaps it is superfluous for me to point out that this proposition has _no
relation_ to such cases as that of water, which, by the presence of other
bodies, is rendered a better conductor of electricity, and _therefore_ is
more freely decomposed.

832. vii. The nature of the substance of which the electrode is formed,
provided it be a conductor, causes no difference in the
electro-decomposition, either in kind or degree (807. 813.): but it
seriously influences, by secondary action (714.), the state in which the
finally appear. Advantage may be taken of this principle in combining and
_ions_ collecting such _ions_ as, if evolved in their _free_ state, would
be unmanageable[A].

[A] It will often happen that the electrodes used may be of such a
nature as, with the fluid in which they are immersed, to produce an
electric current, either according with or opposing that of the
voltaic arrangement used, and in this way, or by direct chemical
action, may sadly disturb the results. Still, in the midst of all
these confusing effects, the electric current, which actually passes
in any direction through the body suffering decomposition, will
produce its own definite electrolytic action.

833. viii. A substance which, being used as the electrode, can combine with
the _ion_ evolved against it, is also, I believe, an _ion_, and combines,
in such cases, in the quantity represented by its _electro-chemical
equivalent_. All the experiments I have made agree with this view; and it
seems to me, at present, to result as a necessary consequence. Whether, in
the secondary actions that take place, where the _ion_ acts, not upon the
matter of the electrode, but on that which is around it in the liquid
(744.), the same consequence follows, will require more extended
investigation to determine.

834. ix. Compound _ions_ are not necessarily composed of electro-chemical
equivalents of simple _ions_. For instance, sulphuric acid, boracic acid,
phosphoric acid, are _ions_, but not _electrolytes_, i.e. not composed of
electro-chemical equiv