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As previously mentioned, the discovery of the electric current
was made possible owing to Volta after whom the unit of electric
pressure, the volt, was named.
Volta was born at Como, in Italy, February 18, 1745. For
some years he was a teacher of physics in his home town. Later on
he became professor of natural sciences at the University of Pavia.
After his famous discovery he travelled in many countries, among
them France, Germany and England. He was also invited to Paris
to lecture on the newly discovered chemical source of continuous
current. In 1819 he returned to Como where he spent the rest of his
life. Volta died at the age of 82.
Volta took great interest in Galvani’s researches. He began to
carry on similar experiments and soon found out that the electric
source was not within the frog’s leg itself, but was the result of the
contact of both dissimilar metals used during his observations.
However, to carry on experiments of such a kind was not an easy
thing to do. He spent the next few years trying to invent a source
of a steady, continuous current. To increase the effect obtained
with one pair of metals, Volta increased the number of these pairs.
Thus the voltaic pile consisted of a layer of copper and a layer of
zinc placed one above another with a layer of flannel moistened in
salt water between them. In this way the voltaic pile looked like a
thick sandwich containing copper, zinc, flannel moistened in salt
water, copper, zinc, flannel, and so on. A wire was connected to
the first disc of copper and to the last disc of zinc.
The year 1800 is a good date to be remembered: for the first
time in the world’s history a steady, continuous current was
generated.
Text 2
Alfred Nobel

Alfred Nobel (1833-1896), Swedish inventor and
philanthropist, was a man of many contrasts. He was a son of a
bankrupt, but became a millionaire; a scientist with a love of
literature. A lover of mankind, he never had a wife or family to
love him; a patriotic son of his native land, he died alone in a
foreign country. He discovered dynamite for peacetime industries,
but people began to use it as a weapon of war. However, during his
life he was not so well-known as his works. He became famous
only after his death.

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