Page:Dictionary of National Biography volume 23.djvu/101

Gregory house had to be closed. He then went to the Victoria Theatre, where he played on 7 Sept. 1846, and on the following Thursday, 10 Sept., acted Richard III at the Strand Theatre. This was his last appearance on the stage. He was the author of four unpublished dramas, two of which were acted with success. At length, by the force of public opinion, aided by the law courts and the lasting hostility of the Duke of Brunswick, the ‘Satirist’ was suppressed, No. 924, Saturday, 15 Dec. 1849, being the last issue of that journal. Gregory, in March 1847, married Margaret, niece of John Thompson of Frognall Priory, Hampstead, who was generally known as ‘Memory Thompson.’ Thompson died just before the marriage, and Gregory came into Thompson's money, which with his own savings made him a comparatively well-to-do man. After an illness of three years, of disease of the lungs, he died at The Priory, 22 Aberdeen Place, St. John's Wood, London, on 24 Nov. 1852, aged 56. His will, dated 17 Nov. 1852, was proved 22 April 1853. It is now at Somerset House, and in it he speaks of a daughter by a first wife who had greatly offended him, and he refers in bitter terms to ‘his enemy’ the Duke of Brunswick.

[Era, 19 Feb. 1843, p. 6; The Theatre, September 1878, pp. 117–21, by Dutton Cook; the Rev. J. Richardson's Recollections (1855), i. 22, 25–8, ii. 181–3; Cobbett's Weekly Political Register, 10 Sept. 1832, pp. 395–8.]  GREGORY, DAVID (1661–1708), astonomer, was the eldest son of David Gregory (1627-1720) [q. v.] of Kinniardie in Banffshire, where he was born on 24 June 1661. From Marischal College, Aberdeen, he entered the university of Edinburgh, and graduated M.A. on 28 Nov. 1683. He had a month previously been elected to the mathematical chair occupied in 1674 and 1676 by his uncle, James Greggory [q. v.], the possession of whose papers had directed his attention to mathematics. A salary of 1000l, Scots was attached to the office. His inaugural address, ‘De Analyseos Geometricæ progressu et incrementis,’ is lost; but he published at Edinburgh, in 1684, ‘Exercitatio Geometrica de Dimensione Figurarum,’ in which, with the help of his uncle's memoranda, he extended the method of quadratures by infinite series. A notice of the work appeared in the ‘Philosophical Transactions’ (xiv. 730). Gregory was the first professor who publicly lectured on the Newtonian philosophy. His enthusiasm for the ‘Principia’ reacted even on Englishmen. Whiston relates (Memoirs, p. 36) that he himself was led to its study by Gregory's ‘prodigious commendations.’ A collection of notes from his lectures, preserved in the university library at Edinburgh, shows that they covered an unusually wide range, their subjects including geodesy, optics, and dynamics, as well as the various branches of mathematics. The inquisitorial proceedings of the committee of visitation to the university, appointed under the act of 4 July 1690, caused him much annoyance; and his refusal to subscribe the confession rendered his position precarious. He accordingly went to London in 1691, with a view to the Savilian chair of astronomy at Oxford, then about to be vacated by Dr. Edward Bernard [q. v,], and was introduced to Newton, whose intimate friend he became. Newton recommended him to Flamsteed as ‘a very ingenious person and good mathematician worth your acquaintance,’ and spoke of him as a probable successor in the reform of planetary theories (, Flamsteed, p. 129). Chosen Savilian professor before the close of the year through the combined influence of Newton and Flamsteed, he took the degrees of M.A. and M.D. at. Oxford on 6 and 18 Feb. 1692 respectively, and became master commoner of Balliol College. He was elected a fellow of the Royal Society on 30 Nov. 1692.

His ‘Catoptricæ et Dioptricæ Elementa’ (Oxford, 1695), purposely adapted to undergraduates, contained the substance of lectures delivered at Edinburgh in 1684. A concluding remark (p. 98), as to the possibility of counteracting colour-aberration in lenses, by combining in them media of different densities, gave the first hint of the achromatic telescope. The treatise was reprinted at Edinburgh in 1713, and translated into English by Sir William Browne [q. v.] in 1715 (2nd ed., with appendix by Desaguliers, London, 1735). Gregory married, in 1695, Elizabeth, daughter of Mr. Oliphant, of Langtoun in Scotland, and had by her four children. He secured in 1699, through his interest with Bishop Burnet, the appointment of mathematical tutor to William, Duke of Gloucester, whose early death forestalled his instructions. His success was viewed with some bitterness by Flamsteed, who had aspired to the post.

Gregory's principal work, ‘Astronomiæ Physicæ et Geometricæ; Elementa,’ was published, with a dedication to Prince George of Denmark, at Oxford in 1702. It was the first textbook composed on gravitational principles, and remodelling astronomy in conformity with physical theory (Phil. Trans. xxiii. 1312; Acta Eruditorum, 1703, p. 452). Newton thought highly of the book, and communicated, for insertion in it (p. 332), his ‘lunar theory,’ long the guide of practical