Whilst Galvani persisted in this mistake until his death, Volta
realized that the source of the electric force, as in the first of
Galvani's observations, must still be sought outside the specimens, and
himself rightly attributed it to the contacting metals. Guided by this
hypothesis, Volta started systematic research into the Galvanic
properties of metals, and presently succeeded in producing electricity
once more from purely mineral substances, namely from two different
metals in contact with a conductive liquid.

This mode of producing electricity, however, differed from any
previously known in allowing for the first time the production of
continuous electrical effects. It is this quality of the cells and
piles constructed by Volta that laid open the road for electric force
to assume that role in human civilization which we have already
described. That Volta himself was aware of this essentially new factor
in the Galvanic production of electricity is shown by his own report to
the Royal Society:

'The chief of my results, and which comprehends nearly all the others,
is the construction of an apparatus which resembles in its effects,
viz. such as giving shocks to the arms, &c, the Leyden phial, and still
better electric batteries weakly charged; . . . but which infinitely
surpasses the virtue and power of these same batteries; as it has no
need, like them, of being charged beforehand, by means of a foreign
electricity; and as it is capable of giving the usual commotion as
often as ever it is properly touched.'

Whilst Volta's success was based on avoiding Galvani's error, his
apparatus nevertheless turned out inadvertently to be a close