liant and constant star of
light if interrupted anywhere by charcoal points. It will not be too
much to say that this necessary quantity of electricity is equal to a
very powerful flash of lightning; and yet when it has performed its full
work of electrolysis, it has separated the elements of only a single
grain of water.

On the other hand, the relation between the conduction of the
electricity and the decomposition of the water is so close that one
cannot take place without the other. If the water be altered only in
that degree which consists in its having the solid instead of the fluid
state, the conduction is stopped and the decomposition is stopped with
it. Whether the conduction be considered as depending upon the
decomposition or not, still the relation of the two functions is equally
intimate.

Considering this close and twofold relation--namely, that without
decomposition transmission of electricity does not occur, and that for a
given definite quantity of electricity passed an equally definite and
constant quantity of water or other matter is decomposed; considering
also that the agent, which is electricity, is simply employed in
overcoming electrical powers in the body subjected to its action, it
seems a probable and almost a natural consequence that the quantity
which passes is the equivalent of that of the particles separated;
_i.e._, that if the electrical power which holds the elements of a grain
of water in combination, or which makes a grain of oxygen and hydrogen
in the right proportions unite into water when they are made to combine,
could be thrown into a current, it would exactly equal the current
required for the separation of that grain of water into its elements
again; in other words, that the electricity which decomposes and that
which is evolved by the decomposition of a certain quantity of matter
are alike.

This view of the subject gives an almost overwhelming idea of the
extraordinary quantity or degree of electric power which naturally
belongs to the particles of matter, and the idea may be illustrated by
reference to the voltaic pile.

The source of the electricity in the voltaic instrument is due almost
entirely to chemical action. Substances interposed between its metals
are all electrolytes, and the current cannot be transmitted without
their decomposition. If, now, a voltaic trough have its extremities
connected by a body capable of being decomposed, such as water, we shall
have