JOHANN Jscon, Baron, one of the greatest of recent chemists, was b. at Westerl6sa. in e. Gothlam1, Sweden, 20th Aug., 1779. While studying for the medical profession at the university of •psala, he was more attracted by the preparatory natu ral sciences. especially chemistry. After being some time employed in medical practice and lecturing, he was appointed (1806) lecturer on chemistry in the military academy 'of Stockholm, and, in the following year, professor of medicine and pharmacy. lie was shortly after chosen president of the Stockholm academy of sciences; and from 1818 till his death, 7th Aug., 1848, held the office of perpetual secretary. The king raised hint to the rank of baron; other honors from learned societies were conferred on him; and the directors of the Swedish ironworks, in consideration of the value of his researches iu their particular branch of industry, bestowed on him a pension for life. In 1838. he was made a senator; but he took little part in politics. The field of his activity lay in his laboratory, where he acquired a name of which his country is justly proud. his services to chemistry are too vast to be described here. The science of chemistry. as at present organized. rests in a great measure upon the discoveries and views of B.. although in not a few points he has been controverted, or found wronos His multiplied and accurate analyses established the laws of 'condination on an and to him ice owe the system of chemical symbols Ile discovered the elements selenium and thorium.
and first exhibited calcium. barium, stront u111. columbium or tantalum, silicium, and zirconium, in the metallic form. The blpwpipe iri. hands of. B. became a powerful instrument in the analysis of inorganic substances. The multitude and accuracy of his researches in every branch of chemical inquiry make it difficult to conceive how one man could have accomplished so much. Of his numerous writings, the most important is his i Berrien. (text-book of chemistry, 3 vols., Stock. 1808-18), which has since passed through 5 large editions, on each occasion being almost wholly rewritten. The best known edition is that published in 8 vols. at Brussels in 1835. The book has been translated into every European language. his essay On the Use of the Blowpipe exhausts the subject, 'while his Annual Reports on the Progress of Physics, Ohemistry, and Mineral ogy, undertaken at the request of the academy of sciences in 1822, have proved very valuable to science. Scarcely less so have been the Memoirs Relative to Physic:4,C hem istry, and Mineralogy, of which he was one of the originators and conductors, and to which, during the 12 years they were published, from 1806 to 1818, he contributed 47 original papers.