BLACK, JOSEPH, an eminent chemist, was b. in 1728, at Bordeaux, where his father was engaged in the wine-trade. Both his parents were of Scotch descent. but natives of Belfast, to which their son was sent for his education in 1740. In 1746, he entered. the university of Glasgow, and studied chemistry tinder Dr. Cullen. In 1751. he went to Edinburgh to complete his medical course, and in 1754 took his degree. His thesis on the nature of the causticity- of lime and the alkalies, which he showed to be owing to the absence of the carbonic acid (called by him fixed air) present in limestone and in what are now called the carbonates of the alkalies, contained his first contribution to chemical science, and excited considerable attention. In 1750, on the removal of Cullen to Edinburgh, B. succeeded hint as professor of anatomy (which branch he afterwards exchanged for medicine) and lecturer on chemistry in Glasgow. Between 1759 and 1763, he evolved that theory of " latent heat" on which his scientific fame chiefly rests, and which formed the immediate preliminary to the next great stride in discovery by his pupil and assistant .lames Watt. In 1700. Cullen NV:IS appointed to the chair of
theoretical medicine in Edinburgh, and 13. succeeded Mtn in tho chair of chemistry. Thenceforth he devoted himself chiefly to the elaboration of his lectures, in which Ito aimed at the ntmast degree of perspicuity, and with perfect success. Ills class became one of the most popular in the university: it occasioned, however, some disappointment that one so capable of enlarging its territory made no further contributions to chemistry. Though of an extremely delicate constitution. he prolonged his life, by care mid tem perance, to the age of 71. Ile died on the 26th Nov.. 1799. Ills lectures were published in 1803 (Edin., 2 vols., 4to), edited, with a biographical and critical preface, by prof. Robison.