7 Alessandro Volta 7electricity. He became professor of physics at the Royal
School of Como in 1774 and discovered and isolated meth-
ane gas in 1778. One year later he was appointed to the
chair of physics at the University of Pavia.
In 1780 Volta’s friend Luigi Galvani discovered that
contact of two different metals with the muscle of a frog
resulted in the generation of an electric current. Volta had
been studying how electricity stimulates the senses of
touch, taste, and sight. When Volta put a metal coin on
top of his tongue and another coin of a different metal
under his tongue and connected their surfaces with a wire,
the coins tasted salty. Like Galvani, Volta assumed that he
was working with animal electricity until 1796 when he
discovered that he could also produce a current when he
substituted a piece of cardboard soaked in brine for his
tongue. Volta correctly conjectured that the effect was
caused by the contact between metal and a moist body.
Around 1800 he constructed what is now known as a vol-
taic pile consisting of layers of silver, moist cardboard,
and zinc, repeated in that order, beginning and ending
with a different metal. When he joined the silver and the
zinc with a wire, electricity flowed continuously through
the wire. This rudimentary form of battery produced a
smaller voltage than the Leyden jar, an earlier device for
storing static electricity, but it was easier to use because it
could supply a steady current and did not have to be
recharged.
In 1801 in Paris, Volta gave a demonstration of his bat-
tery’s generation of electric current before Napoleon, who
made Volta a count and senator of the kingdom of
Lombardy. The emperor of Austria made him director of
the philosophical faculty at the University of Padua in 1815.
The volt, a unit of the electromotive force that drives cur-
rent, was named in his honour in 1881.