m the water; for, in fact, no such
action takes place. But it would also appear that it has power so far to
act, by its attraction for the oxygen of the particles in contact with it,
as to place the similar forces already active between these and the other
particles of oxygen and the particles of hydrogen in the water, in a
peculiar state of tension or polarity, and probably also at the same time
to throw those of its own particles which are in contact with the water
into a similar but opposed state. Whilst this state is retained, no further
change occurs; but when it is relieved, by completion of the circuit, in
which case the forces determined in opposite directions, with respect to
the zinc and the electrolyte, are found exactly competent to neutralize
each other, then a series of decompositions and recompositions takes place
amongst the particles of oxygen and hydrogen constituting the water,
between the place of contact with the platina and the place where the zinc
is active; these intervening particles being evidently in close dependence
upon and relation to each other. The zinc forms a direct compound with
those particles of oxygen which were, previously, in divided relation to
both it and the hydrogen: the oxide is removed by the acid, and a fresh
surface of zinc is presented to the water, to renew and repeat the action.

950. Practically, the state of tension is best relieved by dipping a metal
which has less attraction for oxygen than the zinc, into the dilute acid,
and making it also touch the zinc. The force of chemical affinity, which
has been influenced or polarized in the particles of the water by the
dominant attraction of the zinc for the oxygen, is then transferred, in a
most extraordinary manner, through the two metals, so as to re-enter upon
the circuit in the electrolytic conductor, which, unlike the metals in that
respect, cannot convey or transfer it without suffering decomposition; or
rather, probably, it is exactly balanced and neutralized by the force which
at the same moment completes the combination of the zinc with the oxygen of
the water. The forces, in fact, of the two particles which are acting
towards each other, and which are therefore in opposite directions, are the
origin of the two opposite forces, or directions of force, in the current.
They are of necessity equivalent to each other. Being transferred forward
in contrary directions, they produce what is called the voltaic current:
and