The Italian physicist and chemist Amedeo Avogadro, b. Aug. 9, 1776, d. July 9, 1856, is known principally for the law in chemistry that now bears his name, Avogadro's law. Born of a family of ecclesiastical lawyers, Avogadro received his doctorate in ecclesiastical law in 1796. He was professor of natural philosophy at the College of Vercelli (1809-20) and occupied the first chair of mathematical physics in Italy at the University of Turin (1820-22; 1834-50). In his famous law, Avogadro explained Gay-Lussac's law of combining volumes (see gas laws), established the formula of water as H(2)O (rather than the accepted HO), distinguished between atoms and molecules (the term molecule being coined by Avogadro), distinguished atomic weights from molecular weights, and permitted the calculation of atomic weights without recourse to John Dalton's rules. Avogadro made constant use of a mathematical approach and can be regarded as one of the founders of physical chemistry.
George B. Kauffman
Bibliography: Asimov, Isaac, A Short History of Chemistry (1965, repr. 1979); Knight, David, Ideas in Chemistry (1992); Morselli, Mario, Amadeo Avogadro (1984).
Last modified on: Monday, October 20, 1997.