possible, seems in the present state of the subject very unlikely.

507. The view which M. de la Rive has taken (489.), and also MM. Riffault
and Chompre (485.), of the manner in which electro-chemical decomposition
is effected, is very different to that already considered, and is not
affected by either the arguments or facts urged against the latter.
Considering it as stated by the former philosopher, it appears to me to be
incompetent to account for the experiments of decomposition against
surfaces of air (462. 469.) and water (495.), which I have described; for
if the physical differences between metals and humid conductors, which M.
de la Rive supposes to account for the transmission of the compound of
matter and electricity in the latter, and the transmission of the
electricity only with the rejection of the matter in the former, be allowed
for a moment, still the analogy of air to metal is, electrically
considered, so small, that instead of the former replacing the latter
(462.), an effect the very reverse might have been expected. Or if even
that were allowed, the experiment with water (495.), at once sets the
matter at rest, the decomposing pole being now of a substance which is
admitted as competent to transmit the assumed compound of electricity and
matter.

508. With regard to the views of MM. Riffault and Chompre (485.), the
occurrence of decomposition alone in the _course_ of the current is so
contrary to the well-known effects obtained in the forms of experiment
adopted up to this time, that it must be proved before the hypothesis
depending on it need be considered.

509. The consideration of the various theories of electro-chemical
decomposition, whilst it has made me diffident, has also given me
confidence to add another to the number; for it is because the one I have
to propose appears, after the most attentive consideration, to explain and
agree with the immense collection of facts belonging to this branch of
science, and to remain uncontradicted by, or unopposed to, any of them,
that I have been encouraged to give it.

510. Electro-chemical decomposition is well known to depend essentially
upon the _current_ of electricity. I have shown that in certain cases
(375.) the decomposition is proportionate to the quantity of electricity
passing, whatever may be its intensity or its source, and that the same is
probably true for all cases (377.), even when the utmost generality is
taken on the one hand, an