Samuel Hunter Christie

Samuel Hunter Christie ( born March 22, 1784 in London, † January 24, 1865 in Ailsa Villa, Twickenham, London ) was a British mathematician and naturalist.

Life and work

Christie was born in London. He studied mathematics from 1800 at Trinity College, Cambridge, in the third year he received a scholarship. There he acquired in 1805 as the second best in his class a bachelor, in his spare time, he was among the founders of the rowing club. From 1806 he worked as a mathematical assistant at the Royal Military Academy at Woolwich. There he taught from 1838 to 1854 as a professor mathematics. In the course of its activities, in particular the examination system at the Academy has been largely converted to his work out. His research focused mainly on magnetism, new issues have resulted inter alia from research expeditions of 1818 and 1819 in the Arctic. A hypothesis derived from it he made before 1820 in the Philosophical Transactions. In June 1824 he presented some of his experiments on the influence of temperature on the magnetism at a meeting of the Royal Society, the results were confirmed on an expedition under Parry.

In 1826 he was elected as a member ( "Fellow" ) to the Royal Society and also served as its secretary from 1837 to 1854. 1833 elected to the Royal Society from his writing to the electromagnetic behavior of various metals as Bacerian Lecture. Therein, it has, for example, by that the conductivity of various metals is reduced with increasing length and improves with increased diameter of the wire. He also was able to demonstrate the direct, non-thermal effects of solar radiation on a magnetic needle. His hypothesis that the Earth's magnetic field is due to the influence of the sun, he could not prove experimentally.

He used the first a torsion balance to measure the magnetic force, and he dealt with horizontally and vertically movable magnetic needles. He was a member of a committee for the compass being. The seised itself with the Earth's magnetic field and its possible causes part of the Report of the British Association for 1833 comes from Christie. Humboldt was referring to 1836 in a letter to the President of the Royal Society on the observation of the geomagnetic field on Christie and George Airy. This revealed the 1838 einrichtete the United Kingdom in several places of his dominion permanently manned monitoring stations for the geomagnetic field.

Already in 1833, described Christie, the basic principle of the Wheatstone bridge in a paper for the University of Cambridge. Only a few years later Charles Wheatstone recognized its importance and its versatility, Wheatstone pointed to Christie as the inventor of the bridge, but this was named after Wheatstone, because he had done their importance and usefulness to the public. Stig Ekelöf discussed in The Genesis of the Wheatstone bridge, the contributions of Christie and Wheatstone, and why the bridge Wheatstone's got name.

Beginning in 1864, Christie moved for health reasons at times to Lausanne. He was married twice, his first wife of 12 May 1808 to her death on May 27, 1829 Elizabeth Theodora, the oldest daughter of Charles Claydon, Battler of Trinity College, Cambridge. Her grave is located in the All Saints Church, Cambridge. The second marriage he went on 16 October 1844 with Margaret Ellen, daughter of James Malcolm of Killarney. His son was the astronomer William Christie.