Russian chemist, astronomer, grammarian, poet, historian. Studied science in Moscow, 1731-1735; at University of Imperial Academy of Sciences, St. Petersburg, 1736; then in Germany at Marburg (with C. Wolff), 1736; and at Freiberg, 1739; Professor at University of Imperial Academy of Sciences, 1745 (later rector), built laboratory for teaching and research, 1749; established factory for making colored glass and mosaics; Secretary of State, 1764; member St. Petersburg Academy Sciences, 1741; wrote several memoirs for "Comentarii" of St. Petersburg Academy. Urged importance of study of chemistry in Russia; stressed especially it be developed mathematically; noted increase in weight when lead converted into minum; strongly criticized pholgiston theory; explicitly stated idea of conservation of matter; regarded heat as form of motion of particles (hence often considered anticipator of kinetic theory of gases); developed theory of gases which assumes particles rotating and motion transmitted from particle to particle by friction between their rough surfaces; experimented on expansion of air by heat; first to record freezing of mercury; first to observe atmosphere of Venus (during solar transit, 1761); adopted Wolffian rationalistic approach to science; researches in metallurgy, geology, meteorology, cartography; translated textbooks into Russian; wrote grammar that reformed Russian literary language; published first history of Russia, 1760; (with Euler) helped found University of Moscow; often called founder of Russian science; wrote poems, drama.