=Carl Wilhelm Scheele= was born in 1742 at Stralsund. When fourteen years of age he was apprenticed to an apothecary at Gothenburg, and began the study of experimental chemistry, which he continued to prosecute as an apothecary at Malmö, Stockholm, Upsala, and eventually at Köping on Lake Malar, where he died in 1786, in the forty-third year of his age. During the comparatively short period of his scientific activity Scheele made himself the greatest chemical discoverer of his time. [Illustration: CARL WILHELM SCHEELE. From the statue by Börjeson at Stockholm.] He first isolated chlorine, and determined the individuality of manganese and baryta. He was an independent discoverer of oxygen, ammonia, and hydrogen chloride. He discovered also hydrofluoric, nitro-sulphonic, molybdic, tungstic, and arsenic, among the inorganic acids; and lactic, gallic, pyrogallic, oxalic, citric, tartaric, malic, mucic, and uric acids among the organic acids. He isolated glycerine and milk-sugar; determined the nature of microcosmic salt, borax, and Prussian blue, and prepared hydrocyanic acid. He demonstrated that graphite is a form of carbon. He discovered the chemical nature of sulphuretted hydrogen, arsenuretted hydrogen, and the green arsenical pigment known by his name. He invented new processes for preparing ether, powder of algaroth, phosphorus, calomel, and _magnesia alba_. He first prepared ferrous ammonium sulphate, showed how iron may be analytically separated from manganese; and described the method of breaking up mineral silicates by fusion with alkaline carbonates. Scheele’s contributions to chemical theory were slight and unimportant, but as a discoverer he stands pre-eminent. Of the French phlogistians we have space only to mention Duhamel and Macquer. =Henry Louis Duhamel du Monceau= was born at Paris in 1700. He was one of the earliest to make experiments on ossification, and one of the first to detect the difference between potash and soda. =Peter Joseph Macquer= was born in 1718 at Paris. He investigated the nature of Prussian blue (discovered by Diesbach, of Berlin, in 1710), worked on platinum, wrote one of the best text-books of his time, published a dictionary of chemistry, and was an authority of the chemistry of dyeing. In addition to those already mentioned, the most notable names as workers in chemistry in Great Britain during the eighteenth century are Black, Priestley, and Cavendish.