BERZELIUS, JONS JAKOB (17 Swedish chem ist, was born at Vaf versunda Sorgard, near Linkoping, Sweden, on Aug. 20 or 2g, 1779. He studied chemistry and medicine, and graduated as M.D. in 1802 at Uppsala. Appointed assistant professor of botany and pharmacy at Stockholm in the same year, he became full professor in 1807, and from 1815 to 1832 was professor of chemistry in the Caroline medico-chirurgical institution of that city. The Stockholm Academy of Sciences elected him a member in 1808, and in 1818 he became its perpetual secretary. The same year he was ennobled by Charles XIV., who in 1835 further made him a baron. He died at Stockholm on Aug. 7, 1848. During the first few years of his scientific career Berzelius was mainly engaged on questions of physiological chemistry, but about 1807 he began to devote him self to the elucidation of the composition of chemical compounds through study of the law of multiple proportions and the atomic theory. Perceiving the exact determination of atomic and molec ular weights to be of fundamental importance, he spent ten years in ascertaining that constant for some two thousand simple and compound bodies, and the results he published in 1818 at tained a remarkable standard of accuracy, which was still further improved in a second table that appeared in 1826. He used oxygen—in his view the pivot round which the whole of chem istry revolves—as the basis of reference for the atomic weights of other substances, and the data on which he chiefly relied were the proportions of oxygen in oxygen compounds, the doc trines of isomorphism, and Gay Lussac's law of volumes. When Volta's discovery of the electric cell became known, Berzelius, with W. Hisinger (1766-1852), began experiments on the elec trolysis of salt solutions, ammonia, sulphuric acid, etc., and later this work led him to his electrochemical theory, a full exposition of which he gave in his memoir on the Theory of Chemical Pro portions and the Chemical Action of Electricity (1814). This theory was founded on the supposition that the atoms of the elements are electrically polarized, the positive charge predom inating in some and the negative in others, and from it followed his dualistic hypothesis, according to which compounds are made up of two electrically different components. At first this hypo thesis was confined to inorganic chemistry, but later on he ex tended it to organic compounds, which he saw might similarly be regarded as containing a group or groups of atoms—a compound radicle—in place of simple elements. Although his conception of the nature of compound radicles did not long retain general favour—indeed, he himself changed it more than once—he is entitled to rank as one of the chief founders of the radicle theory. He continued and extended the efforts of Lavoisier and his associates to establish a convenient system of chemical no menclature. By using the initial letters of the Latin (occasionally Greek) names of the elements as symbols for them, and adding a small numeral subscript, to show the number of atoms of each present in a compound, he introduced the present system of chemical formulation (see CHEMISTRY). He effected improve ments in analytical methods and the technique of the blowpipe (Ober die Anwendung des Lothrohrs, 182o), of his classification of minerals on a chemical basis, and of many individual re searches such as those on tellurium, selenium, silicon, thorium, titanium, zirconium and molybdenum, most of which he isolated for the first time. Apart from his original memoirs, of which he published over 25o, mostly in Swedish in the Transactions of the Stockholm academy, he published a Lehrbuch der Chemie, which went through five editions (first 1803-18, fifth and Jahresbericht (1821-48), or annual report on the progress of physics and chemistry, prepared at the instance of the Stock holm academy.