Encyclopædia Britannica, Ninth Edition/Gregory (22.)

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.

I. David Gregory (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.

II. James Gregory (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 " Patrick Mathers, archbeadle of the university of St Andrews. "

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 London, where he made the acquaintance of many persons of distinction, and the same year was chosen fellow of the Eoyal 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 176(5 he was appointed professor of the practice of physic in the university of Edinburgh, to whose eminence as a medical school he largely contributed. From his eighteenth year Dr Gregory had been subject at irregular intervals to attacks of gout, and on the morning of February 10th, 1773, he was found dead in bed apparently from the results of this disease. He is the author of A Comparative View of the State and Facul ties 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 (afterwards Lord Woodhouselee), were published at Edinburgh in 1788.

V. James Gregory (1753-1821), professor of the practice of medicine in the university of Edinburgh, eldest son of the preceding, was born at Aberdeen in 1753, and received there the rudiments of his education. He accom- paniel his father to Edinburgh in 1764, and after going through the usual course of literary studies at that uni versity, he was for a short time a student at Christ Church, Oxford. It was there probably that he acquired that taste fur classical learning which afterwards distinguished him. He then entered on the study of medicine at Edin burgh, 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 Cullen in 1790 he was appointed joint-professor of the practice of medicine ; he became sole professor on the death of Dr Cullen in the same year ; and he continued to deliver lectures on that subject, to audiences almost regularly increasing, until his last illness in 1821. He died on the 2d April of that year. As a medical practitioner Dr Gregory was for the last ten years of his life decidedly at the head of the profession in Scotland; and as a professor his quickness and command ing energy of intellect, his power of perspicuous and elegant exposition, and his genuine sense of humour gave him a remarkable ascendency over the minds of his pupils. Besides his Conspectus Medicines Theoretics, 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 the preceding, was born 25th 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 April 24, 1858. Gregory was one of the first in England to advocate the theories of Liebig, and translated several of his works. He is also the author of Outlines of Chemistry, 1845, and an Elementary Treatise on Chemistry reprinted from the Encyclopaedia Britannica, 1855.

VII. Duncan Farquharson Gregory (1813-1844), brother of the preceding, was born 13th April 1813. After studying at the university of Edinburgh he in 1833 entered Trinity College, Cambridge, where he was for a time assistant professor of chemistry, and was one of the founders of the chemical society. He latterly devoted his chief attention to mathematics, in which he made some important discoveries. He died 23d February 1844. The Cambridge Mathematical Journal was originated, and for some time edited, by Gregory; and he also published a Collection of Examples of Processes in the Differential and Integral Calculus, 1841. A Treatise on tJie Application of Analysis to Solid Geometry, which he left unfinished, was completed by W. Walton, and pub lished posthumously in 1846. His Mathematical Writings, edited . by W. Walton, with a biographical memoir by Robert Leslie Ellis, appeared in 1865.