1911 Encyclopædia Britannica/Coulomb, Charles Augustin

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COULOMB, CHARLES AUGUSTIN (1736–1806), French natural philosopher, was born at Angoulême on the 14th of June 1736. He chose the profession of military engineer, spent three years, to the decided injury of his health, at Fort Bourbon, Martinique, and was employed on his return at Rochelle, the Isle of Aix and Cherbourg. In 1781 he was stationed permanently at Paris, but on the outbreak of the Revolution in 1789 he resigned his appointment as intendant des eaux et fontaines, and retired to a small estate which he possessed at Blois. He was recalled to Paris for a time in order to take part in the new determination of weights and measures, which had been decreed by the Revolutionary government. Of the National Institute he was one of the first members; and he was appointed inspector of public instruction in 1802. But his health was already very feeble, and four years later he died at Paris on the 23rd of August 1806. Coulomb is distinguished in the history alike of mechanics and of electricity and magnetism. In 1779 he published an important investigation of the laws of friction (Théorie des machines simples, en ayant regard au frottement de leurs parties et à la roideur des cordages), which was followed twenty years later by a memoir on fluid resistance. In 1785 appeared his Recherches théoriques et expérimentales sur la force de torsion et sur l'élasticité des fils de métal, &c. This memoir contained a description of different forms of his torsion balance, an instrument used by him with great success for the experimental investigation of the distribution of electricity on surfaces and of the laws of electrical and magnetic action, of the mathematical theory of which he may also be regarded as the founder. The practical unit of quantity of electricity, the coulomb, is named after him.