different
metals was a kind of electrical machine.

Among the Italians who caught at Galvani's discovery, the most skilful
and learned was Professor Volta, of Como, who had been an ardent
electrician from his youth. Many of our readers have seen this year the
colossal statue of that great man, which adorns his native city on the
southern shore of the lake. The statue was worthily decreed, because the
matt who contributes ever so little to a grand discovery in
science--provided that little is essential to it--ranks among the
greatest benefactors of his species. And what did the admirable Volta
discover? Reducing the labors of his long life to their simplest
expression, we should say that his just claim to immortality consists in
this,--he found out that the frog had nothing to do with the production
of electricity in Galvani's experiment, but that a wet card or rag would
do as well. This discovery was the central fact of his scientific career
of sixty-four years. It took all of his familiar knowledge of
electricity, acquired in twenty-seven years of entire devotion to the
study, to enable him to interpret Galvani's apparatus so far as to get
rid of the frog; and he spent the remaining thirty-seven years of his
existence in varying the experiment thus freed from that "demd, damp,
moist, unpleasant body." It was a severe affliction to the followers of
Galvani and to the University of Bologna to have their darling theory of
the nervous electricity so rudely yet so unanswerably refuted. "I do not
need your frog!" exclaimed the too impetuous Volta. "Give me two metals
and a moist rag, and I will produce your animal electricity. Your frog
is nothing but a moist conductor, and in this respect is not as good as
a wet rag." This was a decisive fact, and it silenced all but a few of
the disciples of the dead Galvani.

Volta was led to discard the frog by observing that no electric results
followed when the two plates were of the same metal. Suspecting from
this that the frog was merely a conductor (instead of the generator) of
the electric fluid, he tried the experiment with a wet card placed
between two pairs of plates, and thus discovered that the secret lay in
the metals being heterogeneous. But it cost thousands of experiments to
reach this result, and ten years of ceaseless thought and exertion to
arrive at the invention of the "pile," which merely consists of many
pairs of heterogeneous plates, each separated by a moist sub