JONS

JAKOB

See also:

• JONS JAKOB BERZELIUS (1779-1848)

BERZELIUS (1779-1848)  , Swedish chemist, was born at Vafversunda Sorgard, near Linkoping, Sweden, on the loth (or 29th) of August 1779 . After attending the gymnasium school at Linkoping he went to Upsala University, where he studied chemistry and medicine, and graduated as M.D. in 1802 . Appointed assistant professor of botany and pharmacy at Stockholm in the same year, he became full professsor 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 18o8, 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 . His death occurred at Stockholm on the 7th of August 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 himself to what he made the chief object of his life—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 molecular 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 attained 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 chemistry 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 doctrines 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 electrolysis of salt solutions, ammonia, sulphuric acid, &c., 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 Proportions 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 predominating 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 hypothesis was confined to inorganic chemistry, but subsequently he extended 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 . Another service of the utmost importance which he rendered to the study of chemistry was in continuing and extending the efforts of Lavoisier and his associates to establish a convenient system of chemical nomenclature . 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) . Mention should also be made of the numerous improvements he effected in analytical methods and the technique of the blowpipe (Uber die Anwendung des Lothrohrs, 1820), of his classification of minerals on a chemical basis, and of many individual researches 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 250, mostly in Swedish in the Transactions of the Stock-holm Academy, his remarkable literary activity is attested by his Lehrbuch der Chemie, which went through five editions (first 1803–1818, fifth 1843–1848) and by his Jahresbericht or annual report on the progress of physics and chemistry, prepared at the instance of the Stockholm Academy, of which he published 27 vols . (1821–1848) .