JAMES GREGORY, b. at Aberdeen in Nov., 1638 or 1639. He studied at Marischal college, after leaving which, he betook himself to optical science, in which he made his first discoveries. At the age of 24, he invented the reflecting-telescope known by his name, and which he described in a work, entitled Optica Promota. In 1664 or 1665, he went to London with a view to the construction of his telescope; but finding the artists he employed wanting in the skill necessary for grinding the metal for the object-specu him, he passed on to the university of Padua, where he devoted himself to study; and in the year 1667, produced his Vera circuli et Hyperbobre Quadratura, followed, in 1668, by two other works, Geometrice Pars Unicersalis, and Evercitationes Gcometrius. These works led him into correspondence with the greatest mathematicians of the age—New ton, .Huygliens, Wallis, etc. He was immediately, on his return to London. elected. a fellow of the royal society. and in 1669 he obtained the professorship of mathematics at St. Andrews, a chair which he filled for about six years. Here, in 1672, he produced the Great and New Art of Weighing Vanity, etc., which bore to be the work of M. Pat rick Mathers, archbeadle to the university of St. Andrews, the object of which was to expose the ignorance of a prof. Sinclair of Glasgow, who had put a slight on one of the St. Andrews professors. In 1674 Gregory, who had in the meanwhile married Mary, daughter of Mr. George Jamieson. a distinguished painter, was called to Edinburgh to fill the mathematical chair, which lie did for little more than a year. In Oct., 1675, when showing the satellites of Jupiter to some of his pupils, he was struck with total blindness,amf a few days after died at the age of 36. For a particular list and account of his works and discoveries, see Mutton's Philosophical and Mathematical Dictionary. Dr. Hutton describes him as a man of very acute and penetrating possessing an inventive mathematical genius of the first order; somewhat irritable in temper; but exhibiting one of the most amiable characters of a true philosopher—that of being con tent with his fortune: By his marriage with Mary Jamieson, James Gregory had a son of the same name, JAMES GREGORY, M.D., born in 1674, who became professor of medicine in King's col lege, Aberdeen, where he founded the school of medicine. This James Gregory lima
two sons, JAMES GREGORY, M.D. (the second), who succeeded his father in the Aberdeer, professorship; and Joux GuEaony, M.D., who merits particular notice. lie was born at Aberdeen in 1724, where he received his early education; afterwards he studied medi cine at Edinburgh, Leyden, and Paris. After filling in succession the chairs of phi losophy and n licine at Aberdeen, he was appointed, in 1766, professor of the practice of medicine in Et.mbu•gli, where lie long enjoyed high reputation as a teacher and prac ticing physician, along with the greatest personal popularity. He was the intimate friend of the most eminent men of Edinburgh in its most brilliant period. He died Feb. 9, 1773. Among his works are—Elements of the Practice of Physic, 1772; A Ca in parotive View of the State and Faculties of Man with those of the Animal World, 1765; and A Father's Legacy to his Daughters (published after his death). 1793. In 1788 his works were collected in 4 vols. 12mo, by Mr. Tytler (lord Woodhouselee), who prefaced them by a life of the author. A life of him was also written by Mr. Smellie. His son, Dr. JAMES GREGORY (the third), became distinguished as professor of the practice of medi cine at Edinburgh, and a leading man in his profession. He was the author of Phil• osophical and Literary Essays, 2 vc.s. 8vo, Edin. 1792. The son of this Dr. James was the late WILLIAM GREGORY, professor, at one time, of chemistry in King's college, Aberdeen, and %who died April, 1858, as professor of chemistry in the university of Edin burgh. William Gregory was well known by his works on chemistry, and his edition of the inorganic part of Turner's Elements of Chemistry,. the organic part of which, was edited by Liebig. He also translated, 1855, Liebig's Principles of Agricultural Chemistry. Amongst his contributions to chemistry may be noticed his improved processes for the preparation. of hydrochloric acid, muriate of morphia, and oxide of silver, and his memoirs ou the preparation of sulphuric acid, on the preparation of creative, on the decomposition products of uric acid, on the spontaneous decomposition of alloxan, on the purification of chloroform, etc.