William Thomson 1st Baron Kelvin

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William Thomson Kelvin, 1st Baron, 1824–1907, British mathematician and physicist, b. Belfast. He was professor of natural philosophy at the Univ. of Glasgow (1846–99). He is known especially for his work on heat and electricity. In thermodynamics his work of coordinating the theories of heat held by various leading scientists of his time established firmly the law of the conservation of energy as proposed by Joule. He introduced the Kelvin temperature scale, or absolute scale, of temperature. He also discovered the Thomson effect in thermoelectricity. The importance of the discoveries and improvements that he made in connection with the transmission of messages by submarine cables led to his establishment as a leading authority in this field. He invented the reflecting galvanometer and the siphon recorder, an instrument by which telegraphic messages are recorded in ink fed from a siphon.

His brother, James Thomson, 1822–92, an engineer, was professor at Queen's College, Belfast, from 1857 to 1873. He is known for his studies of the variation in melting point with pressure as well as for his research in hydraulics.

See biographies of Baron Kelvin by S. P. Thompson (1910) and A. G. King (1925).

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Kelvin, William Thomson, 1st Baron (1824–1907). Pioneer of thermodynamics and one of the greatest of classical physicists. Educated in Belfast, Glasgow, and Cambridge, he was in 1846 chosen professor of natural philosophy at Glasgow. He remained there for 50 years, and on retirement signed on as a research student. He said that one word characterized his work, ‘failure’. He was not serious: in fact, he had done fundamental research on electromagnetism and light, on telegraphy, and on heat, where he had come up with the idea of an absolute zero of temperature—the scale based on this is named after him. He was happy to turn his talents to practical use, over telegraph cables, liquefaction of gases, and the construction of instruments. The leading physical scientist in Britain, he was made a peer in 1892.

David Knight

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Kelvin, William Thomson, 1st Baron (1824–1907) British physicist and mathematician, b. Belfast, after whom the absolute scale of temperature is named. The Kelvin temperature scale has its zero point at absolute zero and degree intervals the same size as the degree Celsius. The freezing point of water occurs at 273K (0°C or 32°F) and the boiling point at 373K (100°C or 212°F). In thermodynamics, he resolved conflicting interpretations of the first and second laws.