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Andre Marie Ampere: Practitioner of electrical science
AMPERE WAS born on Jan. 22, 1775 at Lyons.
He was educated at home. His mathematical powers developed early: like Blaise Pascal (1623-1662), he had
composed a treatise on comic sections by the age of 13. He had also mastered at 18 , Lagrange's treatise on
Analytical Mechanics. From 1796 to 1801, he earned his living as a private tutor in mathematics, physics
and foreign languages. In 1802, he was appointed to a teaching post at the school at Lyon; and for the next
seven years, Ampere lectured at the Ecole Polytechnique, Paris where he became permanent professor of
mechanics in 1809. In his early years, Ampere saw the sway of the reign of terror following the French Revolution. He witnessed as a boy
the murder of his father in 1789 when every titled person was subject to execution or imprisonment. Trauma
of this tragedy, followed by his wife's death in 1803, made him an embittered person, spending his time as
an introvert. Perhaps, it was this introversion that spurred him to pursue electricity and magnetism where
his contributions earned him an immortal place in history of science. Ampere was apolitical and welcomed
new ideas from England. His correspondence with Humphry Davy (1778-1829) began in 1810 and continued for 15
years in the areas of chemistry. He died on June 10, 1836.
Ampere's published works cover, besides mathematics and physics, psychology, botany and natural history. He
was elected member by the leading scientific societies in Britain and Europe. The International Electrical
Council named in 1896 the practical unit of current as
AMPERE
.
Ampere's significant experiments during 1820 -1827 revolutionised electrical science. It started with the
work reported by Hans Oersted in his paper Experiments about the Electrical Reaction upon the Magnetised Needle
.
Astronomer Arago brought translations of the Oersted paper to Paris and published them in two French
scientific journals (July 21, 1820). He demonstrated the experiment at a meeting in Paris, which Ampere
attended.. In a week, Ampere repeated the experiment with his home-made equipment. Less than two months
after Arago's demonstration, Ampere on September 18, 1820 reported to the French Academy of Sciences his
findings on the effects of electricity in motion. He went beyond Oersted's original effort and defined
differences between electrostatics and electrodynamics.
Ampere went beyond Oersted's original effort and expanded the laboratory configuration. He demonstrated
several other fundamental relationships:
When a solenoid carries a current, it behaves like a "magnetic shell". Whereas two bodies'
charges electro-statistically repel each other, two parallel conductors carrying current in the same
direction attract each other, but repel when the flow in one conductor is in the opposite direction.
The force of the repulsion or attraction is directly proportional to the strength of the currents and
inversely proportional to the square of the distance separating them.
This formula was a mathematical deduction from experimental facts just as Newton deduced inverse square law
of gravitation from astronomical observations, which was acknowledged as his great contribution and Ampere
was called "Newton of Electricity".
Publication of French Journal
Comptses Rendus
was suppressed during 1792-1836. Valuable Ampere papers were communicated during this period and were not
made public until 1885.
(B. Dibner: Ten Founding Fathers of The Electrical Science, Burndy Library Publications, Norwalk, 1954).
R. Parthasarathy
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