Alessandro Volta
- the man who gave his name to the Volt
It is widely known that the Volt is the unit of electomotive force and that
it is named after Alessandro Volta who was an Italian scientist and pioneer of
electrical science. What is less well known is that he invented the first
primary battery and in doing so he moved electrical science from the
electrostatic era into electrodynamic age. His invention of the electrical
battery made possible many further developments, and the basic ideas for his
electrical batteries are still in use today.
Some years earlier when electrical science was still firmly focussed on
electrostatics, he also proposed the idea of a unit of electric tension.
Fortunately his suggestion was not taken up because one of these early units
equated to 13.3 kV!
In his day Volta was a scientist of great fame. Not only was he a leader in
the area of electricity, but he also made significant discoveries in the field
of chemistry.
Early life
Volta, or to give him his full name Alessandro Giuseppe Antonio Anastasio Volta
was born on 18th February 1745 in Como. This is a small town in the duchy of
Milan and on the shores of Lake Como in Northern Italy. His father had
originally been a member of a Jesuit order, but at the age of 41 he decided to
marry a lady who was 22 years younger than himself.
The family was well connected. On his father's side he had three uncles. One
was a Dominican, one a canon, and the other was an archdeacon. On his mother's
side though, the family had more of a leaning toward the law.
When Volta was only seven years old his father died. He had started his
education at the school of rhetoric in Como before his father's death. Then,
five years after his father's death his uncles took charge of his education.
Initially they sent him to a Jesuit college, but later they changed the course
of his education, moving him elsewhere. It was during this period that a friend
named Giulio Cesare Gattoni provided books and guidance to help his study of
electricity. His uncles had decided it would be best for him to study the law
but his interest in the natural sciences was so keen that they allowed him to
follow his interests and take up career in physics and chemistry.
Volta became very absorbed in his studies and from the age of about 20 Volta
studied science more formally. In particular he took an interest in electricity.
He also boldly corresponded with many of the leading scientists of the day. In
1763 when he was just 18 years old, he corresponded with the eminent French
physicist and electrical experimenter, the Abbe Antoine Nollet in Paris. Later
he wrote to Giovanni Battista Beccaria, professor of physics at the University
of Turin and the foremost Italian experimenter in electrostatics. In many of
these letters he showed a considerable degree of insight into the phenomenon of
electricity that was just beginning to be understood.
First Papers
Volta even published some papers. His first was in 1769, and was entitled "De vi
attractiva ignis electrici." This attracted some attention and helped him gain
his first appointment in 1774 when he became a lecturer at the Royal School in
Como. He performed his duties so well that in the following year he was
appointed professor of experimental physics. It was whilst he was at Como that
he made some important discoveries. The first was in 1775 when he invented the
electrophorus, an early form of electrostatic generator. In its original form
Volta's new device consisted of a cake of resin, wax, or other non-conducting
substance placed between two metal plates. The resin rested on the lower plate
and the upper plate had an insulated handle attached to its centre that
permitted it to be lifted from the resin cake. The upper metal plate was then
removed and the upper surface of the resin was charged by friction. The upper
plate, held by the insulated handle, was placed on the resin cake and, by
touching the top plate with a finger, the charge was drawn off to ground. On
lifting the upper plate, it would thus be charged by induction.
Methane discovered
At this time electricity and chemistry were considered to be very closely
related. Hydrogen, or as it was called then, "inflammable air" had been isolated
in 1766, and ten years after this in 1776, Volta discovered a new gas that we
know as methane today. In his researches, Volta became intrigued by the many
different kinds of "air" that could be found, one of which could be seen
bubbling from lakes and ponds. Although he noted that methane was less explosive
than hydrogen, he used it in what was termed an inflammable air pistol that he
fired using an electric spark. This contraption was surprisingly effective
firing a lead ball and denting wood at a distance of 5 metres. From some related
experiments he also discovered that air consisted of around 20% oxygen.
His discovery of methane in particular brought him considerable renown and as
a result he received a travel grant from the Austrian government that ruled
northern Italy at this time. This enabled him to travel to other countries to
meet other notable scientists. The first of his travels began in early September
1777 with visits to fellow scientists in Switzerland, Alsace and Savoia. He
travelled widely and this enabled him to meet with other scientists and discuss
their work together.
With the rise of Volta's fame came the offer of a university chair. In 1779
he was appointed to the post of professor of experimental physics at the
University of Pavia. This was a position that Volta held for nearly 40 years.
Volta obviously gained a taste for travel because he made further trips abroad
travelling to France and England in 1781/2 and then in 1784 he travelled to
Germany
Battery work
Volta's most groundbreaking work was that lead to the development of the first
battery. The roots of this work can be traced back to some investigations
performed by a fellow Italian and friend of Volta. He discovered that when an
electrical discharge occurred near a frog's leg whilst it was being dissected,
the discharge made its leg twitch. The Italian professor made many further
researches and this lead to his discovery that when two dissimilar metals were
placed on the leg, and electric current was generated. For many years it was
believed that this was a new form of electricity that they called "animal
electricity".
Volta himself performed many experiments to investigate the phenomenon
further. He even started to place dissimilar metals on his tongue and close to
his eye with various effects. However as he undertook further experiments he
became more convinced that the electricity was being generated by the two
dissimilar metals separated by a solution such as brine. Galvani, though
continued to defend his idea of animal electricity.
Volta refined his experiments further. He discovered that the pair of metals
which produced the best effect was zinc and silver. He also put a number of
cells together in series to produce a larger voltage. First Volta did this by
making the individual cells out of wine goblets with brine in them. The two
electrodes were then dipped into this solution. To increase the voltage he
connected several cells in series to give what is often termed Volta's crown of
cups.
Volta soon found that this approach was very cumbersome and so he developed
another idea. This time the basic cell was made out of two discs of the
dissimilar metals with cardboard soaked in brine between them. By stacking
several of these cells on top of one another a "pile" of cells could be made up
quite easily. The limit of the number of cells in any pile was reached when the
weight of the whole battery started to squeeze the brine out of the bottom
cells. Even so it was possible to build up voltages large enough to give an
electric shock.
Rewards
Volta undertook much of his work against a very changeable political climate.
Northern Italy initially came under Austrian rule, but in 1796 they were driven
out by the French. Although Volta became an official in the new government he
gave up this position soon afterwards as he had a lingering loyalty to the
Austrians. Also the French troops had damaged his laboratory. He made a good
choice because when the Austrians returned in 1799 they closed the University,
but Volta remained free. However just over a year later the French were back.
They re-opened the University and Volta's position as professor was re-instated.
He accepted his position as a citizen of the new republic and visited Paris to
express the University's thanks to Napoleon. This visit proved a triumph for
Volta, re-inforcing his already well known position in the scientific community.
During his life Volta gave many demonstrations throughout Europe and even
Napoleon himself was fascinated by his new discoveries. He was so impressed that
he gave Volta a substantial salary to carry on with his experiments and
investigations. Volta also received other recognition for his work. He was made
a count and a senator of the Kingdom of Lombardy and this further increased his
wealth. In addition to this he also received international recognition for his
work. Interestingly the Emperor of Austria made him a director of the
philosophical faculty of the University of Padua in 1815.
Private life
Volta did not marry until 1794 when he was nearly 50 years of age. His bride,
Signorina Teresa Peregrini was much younger than himself and was the youngest
daughter of Count Ludovico Peregrini. The couple had three sons, but to their
great sorrow, the middle son died at the age of 18. He had been a very promising
mathematician, and Volta writing to a friend later said, "This loss strikes me
so much to heart that I do not think I shall ever have another happy day."
After this Volta spent more time with his remaining sons, ensuring they
received a good education. They both entered the University of Pavia and when
they graduated in 1819, the family retired to the ancestral home in Como. The
sons remained within the law profession but in later years the brothers
published a periodical covering the sciences and industry. The older son was
also elected mayor of Como. Apart from his duties as mayor he wrote many studies
of his father, many which were published after Volta's death.
Last years
Volta's fame brought him great wealth and he was able to enjoy a very high
standard of living. Indeed he lived his last years in great luxury until his
death in Como on the 5th May 1827 at the age of 82.
During his life Volta received many honours, being recognised by learned
societies around Europe including London, Berlin and Paris He was also asked to
give many talks and demonstrations. However the greatest honour came after his
death when in 1881 the unit of electromotive force was named the Volt in honour
of the important pioneering work he had undertaken.
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