SCHEELE, KARL WILHELM Swedish chemist, was born at Stralsund, the capital of Pomerania, which then belonged to Sweden, on Dec. 19, 1742. He studied the ele ments of chemistry during his apprenticeship to an apothecary in Gothenburg, with whom he stayed for eight years. In i77o he set tled at Uppsala, where he made the personal acquaintance of Berg man (q.v.). A friendship soon sprang up between the two men, and it has been said that Scheele was Bergman's greatest discov cry. In '775, the year in which he was elected into the Stockholm academy of sciences, he left Stockholm for Koping, a small place on Lake Malar, where he became proprietor of a pharmacy. He found time for an extraordinary amount of original research, and every year he published two or three papers, most of which con tained some discovery or observation of importance. His unre mitting work, it is said, especially at night, induced a rheumatic attack which brought about his death on May 19, 1786.
Scheele's record as a discoverer of new substances is probably unequalled, in spite of his poverty and lack of ordinary laboratory conveniences. His first paper was published in 1770 in conjunc tion with his friend Retzius ; it dealt with the isolation of tartaric acid from cream of tartar. (See ANTIMONY.) The analysis of manganese dioxide in 1774 led him to the discovery of chlorine and baryta, to the description of various salts of manganese itself, including the manganates and permanganates, and to the explana tion of its action in colouring and decolourizing glass. In 1775 he investigated arsenic acid and its reactions, discovering arsine and "Scheele's green" (copper arsenite). (See ARSENIC.) Papers, published in 1776 were concerned with quartz, alum and clay and with the analysis of calculus vesicae from which for the first time he obtained uric acid. In 1777 Scheele prepared sulphuretted hy drogen, and noted the chemical action of light on silver compounds and other substances. (See SULPHUR.) In 1778 he proposed a new method of making calomel and powder of algaroth, and he got molybdic acid from mineral molybdaena nitens which he carefully distinguished from ordinary molybdena (plumbago or black lead of commerce). In the following year he showed that plumbago consists essentially of carbon, and he published a record of esti mations of the proportions of oxygen in the atmosphere, which he had carried on daily during the whole of 1778—three years before Cavendish. In 178o he proved that the acidity of sour
milk is due to what was afterwards called lactic acid; and by boiling milk sugar with nitric acid he obtained mucic acid.
His next discovery, in 1781, was in connection with the mineral scheelite (calcium tungstate), from which he obtained tungstic acid. In 1782 he published some experiments on the formation of ether, and in 1783 examined the properties of glycerine, which he had discovered seven years before. About the same time in the course of some work on Prussian blue he described the com position, properties and compounds of prussic acid, and even ascertained its smell and taste, quite unaware of its poisonous character. In the last years of his life he returned to the vegetable acids, and investigated citric, malic, oxalic and gallic acids (qq.v.). His only book, on Air and Fire, was published in 1777, but was written some years before. The manuscript was in the hands of the printers in 1775, and most of the experimental work for it was done before 1773. One of the chief observations recorded in it is that the atmosphere is composed of two gases—one which supports combustion and the other which prevents it. The former, "fire-air," or oxygen, he prepared from "acid of nitre," from saltpetre, from black oxide of manganese, from oxide of mer cury and other substances, and there is little doubt but that he obtained the gas two years before Priestley. Owing to the delay in the publication of his results he is rarely given credit for this discovery. Scheele remained in favour of the phlogiston theory (see CHEMISTRY : History of) until his death ; he apparently thought that hydrogen, which he had obtained by the action of certain acids on iron or zinc was pure phlogiston.
A list of Scheele's papers is given in Poggendorff's Biographisch-lit erarisches Handworterbuch (Leipzig, 1863). They were collected and published in French as Memoires de chymie (Paris, 1785-88) ; in Eng lish as Chemical Essays, by Thomas Beddoes (1786) ; in Latin as Opuscula, translated by Schafer, edited by Hebenstreit (Leipzig, 1788 89) ; and in German as Samtliche Werke (ed. by Hermbstadt, 1793). The work on Air and Fire appeared in German at Leipzig and Uppsala in 1777, and again in 1782 ; in English (ed. by J. R. Forster 178o) ; and in French (ed. by Dietrich, 1781). See W. A. Tilden, Famous Chemists (1921).