MAGNUS, HEINRICH GUSTAV (1802-187o), German chemist and physicist, was born at Berlin on May 2, 1802. After studying at Berlin, he went to Stockholm to work under Berzelius, and later to Paris, where he studied for a while under Gay-Lussac and Thenard. In 1831 he returned to Berlin as lecturer on tech nology and physics at the university; in 1834 he was elected extraordinary, and in 1845 ordinary professor. He was entrusted by the government with several missions, and in 1865 represented Prussia in the conference called at Frankfort to introduce a uni form metric system of weights and measures into Germany. He died on April 4, 1870. As a teacher his success was rapid and extraordinary. His lucid style and the perfection of his experi mental demonstrations drew to his lectures a crowd of enthusiastic scholars, on whom he impressed the importance of applied science by conducting them round the factories and workshops of the city; and he further found time to hold weekly "colloquies" on physical questions at his house with a small circle of young students. From 1827 to 1833 he was occupied mainly with
chemical researches, which resulted in the discovery of the first of the platino-ammonium compounds ("Magnus's green salt" is Pt(NH3)2C12) of "sulphovinic," "ethionic" and "isethionic" acids and their salts, and, in conjunction with C. F. Ammermiiller, of periodic acid. Among other subjects at which he subsequently worked were the absorption of gases in blood (1837-1845), the expansion of gases by heat the vapour pressures of water and various solutions (1844-1854), thermoelectricity (1851), electrolysis (1856), induction of currents (1858-1861), conduction of heat in gases (1860), and polarization of heat (1866-1868).
See Allgemeine deutsche Biog. The Royal Society's Catalogue enum erates 84 papers by Magnus, most of which originally appeared in Poggendorff's Annalen.