Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/194

Rh of one of the oldest and most powerful Christian families in the country ; at his baptism he received the name of George, that of Gregory not having been assumed until his consecration at least thirty years afterwards. He received his education under the superintendence of his uncle Gallus, at that time bishop of Clermont, and afterwards under Avitus, who succeeded to that see. Having been ordained a deacon on attaining the canonical age, the youthful Georgius Florentius for a time attended in some ecclesiasti cal capacity the court of Sigebert of Austrasia ; and when in 573 a vacancy occurred in the see of Tours, which had been occupied by many of his kindred, his reputation for piety and wisdom led to his being immediately designated as a suitable successor to that bishopric. Circumstances soon occurred which brought into great prominence his peculiar fitness for this post ; first in 575, when Guntran had taken refuge from Chilperic in the sanctuary of St Martin, and afterwards in 577, when Pretextatus of Rouen had been unjustly condemned by the rest of his brethren. The firmness and courage which he showed on these and other occasions brought upon him the bitter hostility of the strong-minded Queen Fredegond, who caused him to be sum moned before a council at Braine on a charge of treason, of which, however, he was acquitted. In 581 he took a lead ing part in adjusting that arrangement between Chilperic and Childebert which gave peace to France for many years. During the later years of his life he used his political influ ence and prestige, which were now immense, with singular unselfishness aud judgment in the interest alike of his diocese and of the whole country. He died at Tours on the 17th of November 594, and subsequently attained the honours of beatification and canonization, his day in the calendar (semiduplex) being November 17th.

 GREGORY, the name of a Scottish family, many mem bers of which attained high eminence in various depart ments of science, sixteen having held professorships. Of the most distinguished of their number a notice is given below.

(1628-1720), eldest son of the Rev. John Gregory of Drumoak, Aberdeenshire, was born in 1628. For some time he was connected with a mercantile house in Holland, but on succeeding to the family estate of Kinardie he returned to Scotland, and occupied most of his time in scientific pursuits, freely giving his poorer neigh bours 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 witch craft before the presbytery of Aberdeen, but he succeeded in convincing that body of his innocence. He died in 1720.

(1638-1675), the author of import ant discoveries in mathematics and optics, younger brother of the preceding, was born in 1638. He 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 before completing his twenty-third year 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 Hypetliolae Quadratures, in which he pro pounded his method of an infinitely converging series for the areas of the circle and hyperbola. In the following year he published also at Padua Geometries Pars Universalis, in which he laid down a series of rules for the transmutation of curves and the measurement of their solids of revolution. On his return to England in this year he was elected a member of the Royal Society ; in the following year 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 show ing 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 at the early age of thirty-seven. Besides the works already mentioned Gregory is the author of Ejcercitalioncs Geometrical, 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 contemporary writer on hydraulics, and published at Glasgow in 1672, professedly by &quot; Patrick Mathers, archbeadle of the university of St Andrews. &quot;

III. DAVID GREGORY (1661-1708), nephew of the pre ceding and son of the David Gregory above mentioned, was born in Aberdeen in 1661. He was educated partly in his native city and partly in Edinburgh, where at the age of twenty-three he became professor of mathematics. In 1691 he was appointed Savilian professor of astronomy at Oxford, an office which he held till his death in 1708. His principal works are Exercitatio Geometrica de dimen- sione figurarum (1684), Catoptricce et Dioptricoe Spharicce Elementa (1695), and Astronomic? Physicce et Geometricce Elementa (1702), the last a work highly esteemed by Newton, of whose system it is an illustration and a defence. A Treatise on Practical Geometry which he left in manu script was translated from the Latin and published in 1745. He was succeeded in the chair of mathematics in Edin burgh by his brother James; another brother, Charles, was in 1707 appointed professor of mathematics in the uni versity of St Andrews ; and his eldest son, David, became professor of modern history at Oxford, and canon and latterly dean of Christ Church.

IV. JOHN GREGORY (1724-1773), professor of medicine in the university of Edinburgh, grandson of James Gregory, the inventor of the Gregorian telescope, and youngest son of Dr James Gregory, professor of medicine in King s College, Aberdeen, was born at Aberdeen, June 3, 1724. After studying at the grammar school of Aberdeen, and completing his literary course at King s College in that city, he attended the medical classes at Edinburgh university. In 1745 he went to Leyden 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 philo sophy at King s College, but in 1749 he resigned his pro fessorship on account of its duties interfering too much with his practice as a physician. In 1754 he proceeded to 