Tennant, Smithson,1761–1815, English chemist. In 1796 he proved, by burning a diamond, that the diamond consists solely of carbon. In 1804 he announced his discovery of osmium and iridium.
Born Nov. 30, 1761, in Selby, Yorkshire; died Feb. 22,1815, in Boulogne, France. English chemist. Fellow of the Royal Society of London (1785).
Tennant received the degree of doctor of medicine in 1796. He became a professor at Cambridge University in 1813. By oxidizing identical quantities of diamond, graphite, and charcoal with saltpeter, Tennant established (1797) that these substances yield equal quantities of carbon dioxide gas and therefore have an identical chemical makeup. In 1804 he discovered osmium and iridium.