Father of electrodynamics

WILHELM WEBER was born at Hall, Germany on October 24, 1804. His father was professor of theology at the University of Halle.

The environment in the family was academic: his elder brother Ernst became a leading anatomist and physiologist and his younger brother Edward became professor of anatomy of Leipzig.

The interest of the three brothers in science was undoubtedly awakened by Langguth, professor of medicine and Chladni, the acoustician, who were family friends.

Weber entered in 1822 the University of Halle and wrote in 1826 his doctoral thesis of the theory of reed organ pipes. He had already begun his first scientific research with his brother Ernst and published in 1825 a treatise on wave motion dealing with water and sound waves.

Weber delivered at Berlin a talk (September 1928) on his work on organ pipes which attracted the attention of the great mathematician Carl Gauss (1777-1855). At Gauss's suggestion, he was called in April 1831 to the chair of physics at Goettingen.

The two formed an unbeatable pair and six years of fruitful collaboration followed, This was brought to an abrupt end by an event which marred Weber's life.

The king of Hanover in 1837 abolished the parliamentary constitution of the State: against this act Weber and six other professors issued a declaration, the consequence of which was their dismissal.

Weber spent five years without an academic position or an income. He adopted a spartan living but continued to work with the apparatus lent by Gauss. Humbolett attempted to get Weber reinstated, but the king insisted on a public retraction which Weber would not accept.

He became in 1843 professor of physics at the University of Leipzig and served till 1849, when he returned to his post at Goettingen.

At his request, his successor J.B. Listing was retained which showed his generosity.

This act created two professors in physics. His famous contributions in electrodynamics were during the period 1849 to 1878.

Gauss and Weber founded the Goettingen Society for Magnetism to conduct investigations. In 1833, the physics laboratory of Weber and the observatory of Gauss were connected by a telegraph line some 9000 feet long, to facilitate simultaneous magnetic observations. Weber developed sensitive magnetometers during the next four years.

At Leipzig, Weber took up the work of settling the absolute unit of electric current. He based this unit on the magnetic effects of current.

This idea was realised by means of the tangent galvanometer. He refined the instrument of Helmholtz (1821-94) such that the horizontal component of the earth's magnetic field (H) was not required. The choice of the unit current (called the ampere) and also the means of fixing it are still valid.

In 1851 Weber began investigation for the systematisation of electrical units, analogous to, and inspired by the work of Gauss in magnetism. With Kohlarush (1809-58), he determined the ratio of the electrostatic and electromagnetic units of electrical quantity by discharging a condenser through a ballistic galvanometer.

The ratio, Weber's constant, turned out to be velocity of light, but research took no special notice of it.

It provided a link between optics and electricity, the unification of which was achieved later by Clerk Maxwell (1831- 79). Weber also determined the absolute value of resistance.

He was the first to regard electric current in terms of elemental units, each with a mass and an electric charge.

His atomistic conception of electric charge, and his vision of its role in determining the electrical, magnetic and thermal properties of matter contributed to the development of physical theory.

At the International Congress held in Paris in 1881 (during Weber's lifetime) the system of units founded by Gauss and Weber was taken up for international acceptance.

The main question was the settle factors by which the absolute units were to be multiplied to provide practical units.

It is a strange fact that, in choosing names for the units, the names of the originators of the whole system did not find a place.

In 1935 the practical unit of magnetic flux was officially named `Weber'. One ten thousandth of 1 weber was called `a gauss'.

Weber's scientific research, initially centred on acoustics, later extended to the domain of electricity and magnetism. Despite a certain lack of recognition, he is reported to have had a contended nature.

Weber received many honours from Germany, France and England, in particular the title of `Geheimrat' and the Copley medal.

He was unmarried: a niece kept house for him. He enjoyed hiking and was a tireless walker till the end of his life (June 23, 1891).

R. Parthasarathy

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