GREGORY  ,' the name of a Scottish

family, many members of which attained high eminence in various departments of science, fourteen having held professorships in mathematics or medicine . Of the most distinguished of their number a notice is given below . I . DAVID GREGORY (1627–1720), eldest son of the Rev . John Gregory of Drumoak, Aberdeenshire, who married Janet Anderson in 1621 . He was for some time connected with a mercantile house in Holland, but on succeeding to the family estate of Kinardie returned to Scotland, and occupied most of his time in scientific pursuits, freely giving his poorer neighbours the benefit of his medical skill . He is said to have been the first possessor of a barometer in the north of Scotland; and on account of his success by means of it in predicting changes in the weather, he was accused of witchcraft before the presbytery of Aberdeen, but he succeeded in convincing that body of his innocence . II . JAMES GREGORY (1638–1675), Scottish mathematician, younger brother of the preceding, was educated at the grammar school of Aberdeen and at Marischal College of that city . At an early period he manifested a strong inclination and capacity for mathematics and kindred sciences; and in 1663 he published his famous treatise Optica promota, in which he made known his great invention, the Gregorian reflecting telescope . About 1665 .he went to the university of Padua, where he studied for some years, and in 1667 published Vera circuli et hyperbolae quadratura, in which he discussed infinite convergent series for the areas of the circle and hyperbola . In the following year he published also at Padua Geometriae pars universalis, in which he gave a series of rules for the rectification of curves and the mensuration of their solids of revolution .

On his return to

England in this year he was elected a fellow of the Royal Society; in 1669 he became professor of mathematics in the university of St Andrews; and in 1674 he was transferred to the chair of mathematics in Edinburgh . In October 1675, while showing the satellites of the planet Jupiter to some of his students through one of his telescopes, he was suddenly struck with blindness, and he died a few days afterwards . He was also the author of Exercitationes geometricae (1668), and, it is alleged, of a satirical tract entitled The Great and New Art of Weighing Vanity, intended to ridicule certain fallacies of a con-temporary writer on hydraulics, and published at Glasgow in 1672, professedly by " Patrick Mathers, archbeadle of the university of St Andrews." ' See A . G . Stewart, The Academic Gregories.which he left in manuscript was translated from the Latin and published in 1745 . He was succeeded in the chair of mathematics in Edinburgh by his brother James; another brother, Charles, was in 1707 appointed professor of mathematics in the university of St Andrews; and his eldest son, David (1696–1767), became professor of modern history at Oxford, and canon and subsequently dean of Christ Church . IV . JOHN GREGORY (1724–1773), Scottish physician, grandson of James Gregory (1638–1675) and youngest son of Dr James Gregory (d . 1731), professor of medicine in King's College, Aberdeen, was born at Aberdeen on the 3rd of June 1724 . He received his early education at the grammar school of Aberdeen and at King's College in that city, and in 1741 he attended the medical classes at Edinburgh university . In 1745 he went to Leiden to complete his medical studies, and during his stay there he received without solicitation the degree of doctor of medicine from King's College, Aberdeen . On his return from Holland he was elected professor of philosophy at King's College, but in 1749 he resigned his professorship on account of its duties interfering too much with his private practice .

In 1754 he proceeded to

London, where he made the acquaintance of many persons of distinction, and the same year was chosen fellow of the Royal Society . On the death in November 1755 of his brother Dr James Gregory, who had succeeded his father as professor of medicine in King's College, Aberdeen, he was appointed to that office . In 1764 he removed to Edinburgh in the hope of obtaining a more extended field of practice as a physician, and in 1766 he was appointed professor of the practice of medicine in the university of Edinburgh, to whose eminence as a medical school he largely contributed . He died of gout on the loth of February 1773 . He is the author of A Comparative View of the State and Faculties of Man with those of the Animal World (1765); Observations on the Duties, Offices and Qualifications of a Physician (1772); Elements of the Practice of Physic (1772); and A Father's Legacy to his Daughters (1774) . His Whole Works, with a life by Mr Tytler (after-wards Lord Woodhouselee), were published at Edinburgh in 1788 . V . JAMES GREGORY (1753-1821), Scottish physician, eldest son of the preceding, was born at Aberdeen in January 1753, He accompanied his father to Edinburgh in 1764, and after going through the usual course of literary studies at that university, he was for a short time a student at Christchurch, Oxford . It was there probably that he acquired that taste for classical learning which afterwards distinguished him . He studied medicine at Edinburgh, and, after graduating doctor of medicine in 1774, spent the greater part of the next two years in Holland, France and Italy . Shortly after his return to Scotland he was appointed in 1776 to the chair his father had formerly held, and in the following year he also entered on the duties of teacher of clinical medicine in the Royal Infirmary . On the illness of Dr William Cullen in 1700 he was appointed joint-professor of the practice of medicine, and he became the head of the Edinburgh Medical School on the death of Dr Cullen in the same year .

He died on the 2nd of

April 1821 . As a medical practitioner Gregory was for the last ten years of his life at the head of the profession in Scotland . He was at one time president of the Edinburgh College of Physicians, but his indiscretion in publishing certain private proceedings of the college led to his suspension on the 13th of May 1809 from all rights and privileges which pertained to the fellowship . Besides his Conspectus medicinae theoreticae, published in 1788 as a text-book for his lectures on the institutes, Dr Gregory was the author of " A Theory of the Moods of Verbs," published in the Edin . Phil . Trans . (1787), and of Literary and Philosophical Essays, published in two volumes in 1792 . VI . WILLIAM GREGORY (1803–1858), son of James Gregory (1753–1821),. was born on the 25th of December 1803 . In 1837 he became professor of chemistry at the Andersonian Institution, Glasgow, in 1839 at King's College, Aberdeen, and in 1844 at Edinburgh University . He died on the 24th of April ,858 . Gregory was one of the first in England to advocate the theories of Justus von Liebig, and translated several of his works .

He is also the author of Outlines of Chemistry (1845), and an Ele. mentary Treatise on Chemistry (1853) . of the preceding, was born on the 13th of April 1813 . After of

Pomerania, on the navigable Ryk, 3 M. from its mouth on studying at the university of Edinburgh he in 1833 entered the Baltic at the little port of Wyk, and 20 M . S.E. from Stralsund Trinity College, Cambridge, where he was for a time assistant professor of chemistry, but he devoted his attention chiefly to mathematics . He died on the 23rd of February 1844 . The Cambridge Mathematical Journal was originated, and for some time edited, by him; and he also published a Collection of Examples of Processes in the Differential and Integral Calculus (1841) . A Treatise on the Application of Analysis to Solid Geometry, which he left unfinished, was completed by W . Walton, and published posthumously in 1846 . His Mathematical Writings, edited by W . Walton, with a biographical memoir by Robert Leslie Ellis, appeared in 1865 .