distance where no electric current is
produced, it is evident that forces of the most intense kind must be
active, and in some way balanced in their activity, during such
combinations; these forces being directed so immediately and exclusively
towards each other, that no signs of the powerful electric current they can
produce become apparent, although the same final state of things is
obtained as if that current had passed. It was Berzelius, I believe, who
considered the heat and light evolved in cases of combustion as the
consequences of this mode of exertion of the electric powers of the
combining particles. But it will require a much more exact and extensive
knowledge of the nature of electricity, and the manner in which it is
associated with the atoms of matter, before we can understand accurately
the action of this power in thus causing their union, or comprehend the
nature of the great difference which it presents in the two modes of action
just distinguished. We may imagine, but such imaginations must for the time
be classed with the great mass of _doubtful knowledge_ (876.) which we
ought rather to strive to diminish than to increase; for the very extensive
contradictions of this knowledge by itself shows that but a small portion
of it can ultimately prove true[A].

[A] Refer to 1738, &c. Series XIV.--_Dec. 1838._

960. Of the two modes of action in which chemical affinity is exerted, it
is important to remark, that that which produces the electric current is as
_definite_ as that which causes ordinary chemical combination; so that in
examining the _production_ or _evolution_ of electricity in cases of
combination or decomposition, it will be necessary, not merely to observe
certain effects dependent upon a current of electricity, but also their
_quantity_: and though it may often happen that the forces concerned in any
particular case of chemical action may be partly exerted in one mode and
partly in the other, it is only those which are efficient in producing the
current that have any relation to voltaic action. Thus, in the combination
of oxygen and hydrogen to produce water, electric powers to a most enormous
amount are for the time active (861. 873.); but any mode of examining the
flame which they form during energetic combination, which has as yet been
devised, has given but the feeblest traces. These therefore may not,
cannot, be taken as evidences of the nature of the action; but are merely
incidental