162 Faraday's Researches

or elementary substances. There is indeed little or no doubt,
that, when the electrical relations of the particles of matter
come to be closely examined, this division must be made. The
simple substances, with cyanogen, sulpho-cyanogen, and one
or two other compound bodies, will probably form the first
group; and the acids and bases, with such analogous com-
pounds as may prove to be ions, the second group. Whether
these will include all ions, or whether a third class of more
complicated results will be required, must be decided by future
experiments.

584. It is -probable that all our present elementary bodies
are ions, but that is not as yet certain. There are some, such
as carbon, phosphorus, nitrogen, silicon, boron, aluminium, the
right of which to the title of ion it is desirable to decide as
soon as possible. There are also many compound bodies,
and amongst them alumina and silica, which it is desirable to
class immediately by unexceptionable experiments. It is also
possible that all combinable bodies, compound as well as simple,
may enter into the class of ions ; but at present it does not
seem to me probable. Still the experimental evidence I have
is so small in proportion to what must gradually accumulate
around, and bear upon, this point, that I am afraid to give a
strong opinion upon it.

585. I think I cannot deceive myself in considering the
doctrine of definite electro-chemical action as of the utmost
importance. It touches by its facts more directly and closely
than any former fact, or set of facts, have done, upon the
beautiful idea that ordinary chemical affinity is a mere conse-
quence of the electrical attractions of the particles of different
kinds of matter; and it will probably lead us to the means by
which we may enlighten that which is at present so obscure, and
either fully demonstrate the truth of the idea, or develop that
which ought to replace it.

586. A very valuable use of electro-chemical equivalents will
be to decide, in cases of doubt, what is the true chemical equiva-
lent, or definite proportional, or atomic number of a body;
for I have such conviction that the power which governs electro-
decomposition and ordinary chemical attractions is the same;
and such confidence in the overruling influence of those natural
laws which render the former definite, as to feel no hesitation
in believing that the latter must submit to them also. • Such
being the case, I can have no doubt that, assuming hydrogen
as i, and dismissing small fractions for the simplicity of expres-'ct' in relation to each