he died at Tours in 595. He was educated by his uncle Gallus, bishop of Clermont, and when not more than twenty-nine, being in minor orders, was consecrated archbishop of Tours. Gregory is chiefly known by his "Historia Francorum." The work gives the history, ecclesiastical and profane, from the establishment of christianity in Gaul to Gregory's own times, and for many of the details found in it and embodied in every history of France, he is the sole authority. His work was translated in 1638 by the abbé de Marolles, and lately by M. Bordier. He wrote a work in eight books on the "Lives of the Saints;" but it has been so interpolated, that it is impossible to say what parts are his. Gregory's position placed him in relations, sometimes of friendship, sometimes of hostility, with the crown. He exhibited in defence of what he regarded as the rights of his bishopric considerable firmness. We find him often actively engaged in the public affairs of his time In 588 he arranges the differences between Childebert and Guntram. In the next year he is at Poitiers, restoring the monastery of St. Croix; and in the same year we hear him storming heaven by prayer, and stunning earth by precedents brought forward to establish an exemption from taxation for the city of Tours and the lands of the archbishop. In 590 he went to Rome. The pope, Gregory the Great, when he presented himself, gazed upon him with surprise. He had expected to see a man of commanding presence. He had measured him by his reputation, and thought of corresponding physical height. He saw a man "chétif" and feeble—in the language of St. Odon, a "homuncio." In 591 we find him in Austrasia, and in 593 with Childebert at the court of Orleans.—J. A., D.
GREGORY or GREGORIE, the surname assumed by one of the branches of the Clan Alpine upon the proscription of their proper surname of MacGregor. The branch in question was established in the north-east of Scotland about the beginning of the seventeenth century, and its head was proprietor of the estate of Kinardie in Banffshire. About the middle of that century some of its members attained an eminence in science which their descendants have maintained for two hundred years—
Gregory, David, eldest son of the Reverend John Gregory, parish minister of Drumoak, and his wife, who was the daughter of a mathematician and mechanic of some note, David Anderson of Finzaugh, was born in 1627 or 1628, and died in 1720, in his ninety-third year. In his youth he was bound apprentice to a mercantile house in Holland. In 1655 he returned to Scotland, and on succeeding soon afterwards to the family estate of Kinardie, he abandoned business, and devoted most of his time to the study of physical science. He had some skill in medicine, which he exerted for the benefit of the poor of his neighbourhood. He was the possessor of the first barometer ever seen in that part of Scotland, and by its aid he predicted changes of the weather with a success which led to his being accused of sorcery before the presbytery of Aberdeen. That body, however, upon inquiring into the case, were satisfied of his innocence of any compact with the powers of evil. As he did not publish any discovery or other result of his labours, his scientific ability is to a great extent left to be inferred from the eminence afterwards attained by his sons, David, James, and Charles. He was twice married, and had thirty-two children. One of his daughters was the mother of the philosopher, Thomas Reid.—W. J. M. R.
Gregory, James, a great mathematician, and the founder of the scientific eminence of his family, was the younger brother of the preceding. He was born at Aberdeen in November, 1638, and died at Edinburgh in October, 1675. He was taught elementary mathematics by his mother (who has already been mentioned at the beginning of the preceding article), and was educated at the grammar-school of Aberdeen, and afterwards at Marischal college, one of the universities of that city. In 1663 he published, in a work called "Optica Promota," his famous invention of the first or "Gregorian" reflecting telescope. In that instrument the principal reflector is of the form of a concave paraboloid, with a round orifice in the centre; it causes the rays which come to it from distant objects nearly parallel to each other, to converge towards a small concave reflector in the centre of the tube, by which they are again reflected through the beforementioned orifice to the magnifying eyepiece of the telescope. Although the simpler forms of reflecting telescope afterwards invented by Newton and Herschel are the best for instruments of great size, the Gregorian form is still used as the most convenient for those of moderate dimensions, on account of the ease with which it can be directed towards an object. In 1664 and 1665 he visited London for the purpose of study and of communication with the men of science of the time, and thence proceeded to Italy, in order to study mathematics at Padua. On his return to England in 1668 he was elected a fellow of the Royal Society. In the same year he was appointed professor of mathematics in the university of St. Andrews, and while there he married Mary, daughter of the painter, George Jamieson. In 1674 he was appointed professor of mathematics in the university of Edinburgh; and there, in October, 1675, while showing his pupils the satellites of Jupiter with his telescope, he was suddenly struck with blindness, and died in a few days afterwards. His principal writings were the following—"Optica Promota," already mentioned; "Vera Circuli et Hyperbolæ Quadratura," a memoir read to the Royal Society in 1667; "Geometriæ Pars Universalis, inserviens quantitatum curvarum transmutationi et mensuræ," 1668; "Exercitationes Geometricae," 1668; and a small satirical work published in 1672, in which, assuming the name of the bedel of the university of St. Andrews, he exposes (but with more science than humour) some fallacies of a contemporary writer on hydraulics.—W. J. M. R.
Gregory, David, son of David Gregory of Kinardie, was born at Aberdeen on the 24th of June, 1661. His education, which was begun at Aberdeen, was carried on at the university of Edinburgh, where he took the degree of master of arts. In 1684, he obtained, at the early age of twenty-three, the professorship of mathematics there; and in that capacity he did an inestimable service to science, held out a bright example to its teachers, and achieved lasting honours for himself, his university, and his nation, by a deed which at the time proved his courage as well as his knowledge—that of being the first of all the professors in the world who expounded to students the discoveries of Newton, and used the Principia as an academic text-book. In 1691 he was elected a fellow of the Royal Society, and in the same year, by the recommendation of Newton, he was appointed Savilian professor of astronomy in the university of Oxford. In 1695 he married Elizabeth, daughter of Oliphant of Langtown. He died at Maidenhead in Berkshire, on the 10th, 11th, or 12th of October, 1708. A monument to his memory stands in St. Mary's church, Oxford. His principal writings were—"Exercitatio Geometrica de Dimensione Figurarum," Edinburgh, 1684, a treatise on the quadrature and rectification of curves; "Catoptricæ et Dioptricæ Sphæricæ Elementa," 1695, being the substance of the optical part of his lectures at Edinburgh (in this work the possibility of making lenses achromatic was anticipated by reasoning, but the means of effecting that improvement were invented and put in practice by Dollond more than half a century afterwards); "Elements of Astronomy," 1702; and various memoirs in the Philosophical Transactions, vols. xviii. to xxv. He edited a highly-prized edition of Euclid's Elements of Geometry in the original Greek, with a Latin translation, and in conjunction with Halley, the Conies of Apollonius.—W. J. M. R.
Gregory, James, brother of the preceding, and his successor in the chair of mathematics in the university of Edinburgh in 1691. In 1725 he retired, and was succeeded by Maclaurin.
Gregory, Charles, brother of the preceding, became professor of mathematics in the university of St. Andrews in 1707, and resigned his chair in 1739, when he was succeeded by his son. He died in 1763.—W. J. M. R.
Gregory, David, a scholar and divine, son of David Gregory, the Savilian professor, was educated at Westminster and at Oxford, where he afterwards became the first occupant of a chair established in that university for modern history and languages. At a later period he was master of Sherburn hospital in the county of Durham. In 1736 he was appointed a canon of Christ Church, and in 1756 dean of Christ Church. He died in 1767.—W. J. M. R.
Gregory, John, a distinguished Scotch physician and professor of medicine, was born at Aberdeen on the 3rd of June, 1724. He was the grandson of the great James Gregory, the inventor of the reflecting telescope, and the son of Dr. James Gregory, the professor of medicine at King's college. After attending the literary classes at Aberdeen, he completed his professional studies at Edinburgh; thence he proceeded to Leyden, which then enjoyed a high reputation as a medical school. He remained in Holland for three years, and while there received from King's college the unsolicited degree of doctor of medicine. He was, not long afterwards, elected professor of moral philo-
