Dictionary of National Biography, 1885-1900/Gregory, David (1661-1708)

​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 (Baily, 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 ​astronomers in determining the moon's motions. The discussion in the preface, in which the doctrine of gravitation was brought into credit on the score of its antiquity, likewise emanated from Newton. The materials for it were found in his handwriting among Gregory's papers (Edinburgh Phil. Trans. xii. 64). Flamsteed complained that Gregory ‘had two or three flings at him,’ the chief cause of offence being the doubt thrown on the reality of his supposed parallax for the pole-star (Baily, Flamsteed, p. 203; Astr. Elementa, p. 275). His hostility was not soothed by Gregory's nomination, in 1704, as one of the committee charged by Prince George with the inspection and printing of the Greenwich observations.

In pursuance of Dr. Bernard's scheme for printing the works of ancient mathematicians, Gregory brought out in 1703, through the University Press, a splendid edition in Greek and Latin, accompanied by an elaborate preface, of all the writings attributed, with any show of authority, to Euclid. He next undertook, with Halley, a joint edition of Apollonius, which, however, he did not live to complete. He was chosen in 1705 an honorary fellow of the Royal College of Physicians of Edinburgh, and took his seat at the board on 4 Oct. In 1708 he was attacked with consumption, and repaired to Bath for the waters. On his return to London, accompanied by his wife, he was stopped by an accession of illness at Maidenhead in Berkshire, and, hoping to continue his journey next morning, sent to Windsor for his friend Dr. Arbuthnot, who found him at the last extremity. He died on 10 Oct. 1708, at the Greyhound Inn, and was buried in the churchyard of Maidenhead. His widow erected a marble monument to him in St. Mary's Church, Oxford. At the time of his death his three sons lay sick and his only daughter dead of small-pox in London. His eldest son David (1696-1767) [q. v.] was afterwards dean of Christ Church.

Gregory appears to have been of an amiable disposition, and was much regretted by his friends. He was a skilful mathematician, but owed his reputation mainly to his promptitude and zeal in adopting the Newtonian philosophy. Flamsteed's description of him as a ‘closet astronomer’ is not inapt. His only recorded observation is of the partial eclipse of the sun on 13 Sept. 1699 (Phil. Trans. xxi. 330). He left manuscript treatises on fluxions, trigonometry, mechanics, and hydrostatics. A tract, ‘De Motu,’ was printed posthumously (in Eames and Martyn's ‘Abridg. Phil. Trans.’ vi. 275, 1734), and a transcript of his ‘Notæ in Isaaci Newtoni Principia Philosophica,’ in three hundred closely written quarto pages, is preserved in the library of the university of Edinburgh. Composed about 1693, it is said at Newton's request, these laborious annotations were submitted to Huygens for his opinion with unknown result. A proposal for printing them, set on foot at Oxford in 1714, fell through (Rigaud, Corresp. of Scientific Men, i. 264). Their compilation suggested Gregory's ‘Astronomy.’ Of this work English editions appeared in 1713 and 1726, and a reprint, revised by C. Huart, at Geneva, in 1726. A treatise embodying Gregory's mathematical lectures was published in an English translation by Maclaurin as ‘A Treatise of Practical Geometry,’ Edinburgh, 1745. Its usefulness as a university text-book carried it into several editions, the ninth appearing in 1780. The following papers were communicated by Gregory to the Royal Society: ‘Solutio Problematis Florentini’ (‘Phil. Trans.’ xviii. 25); ‘Refutations of a charge of Plagiarism against James Gregory’ (ib. p. 233, xxv. 2336); ‘Catenaria’ (ib. xix. 637, and ‘Miscellanea Curiosa,’ vol. ii. 1706), containing demonstrations of various properties of the catenary curve, with the suggestion that its inversion gave the true form of the arch; ‘Responsio ad Animadversionem ad Davidis Gregorii Catenariam’ (‘Phil. Trans.’ xxi. 419, and ‘Acta Erudit.’ 1700, p. 301); ‘De Orbita Cassiniana’ (‘Phil. Trans.’ xxiv. 1704).

A. M. C.