Gregory, David

(1659-1708), mathematician and astronomer

by Anita Guerrini

© Oxford University Press 2004 All rights reserved

Gregory, David (1659-1708), mathematician and astronomer, was born in Upper Kirkgate, Aberdeen, on 3 June 1659, the fourth of fifteen children of David Gregorie (1625-1720), medical practitioner of Kinnairdy in Banffshire, and his first wife, Jean (d. 1671), daughter of Patrick Walker of Orchiston. The younger David Gregory adopted the Anglicized spelling of his surname when he moved to England. In 1664 his father inherited Kinnairdy and the family moved there from Aberdeen. Little is known of Gregory's early life or education, but he probably studied at Aberdeen grammar school. He entered Marischal College, Aberdeen, in 1671, aged twelve, and left four years later, probably without taking a degree. He appears then to have returned to Kinnairdy.

Between 1675 and 1683 Gregory became a proficient mathematician and gained the friendship of the Edinburgh physician Archibald Pitcairne, a major influence in his life. Unfortunately, the chronology of Gregory's life in this critical period remains somewhat obscure. He came from a long line of mathematicians and medical men, and he combined the interests of his forebears in his own work. His uncle the mathematician James Gregorie died in October 1675, leaving his books and papers to his brother. Gregory began to study these in the 1670s.

In 1679 Gregory was sent abroad to complete his education. He matriculated as a medical student at the University of Leiden in September and remained there for several months. He then embarked on a typical peregrination through Europe, with stops at Rotterdam, Paris, and finally London, where he spent the spring of 1681. While in the Netherlands and France, Gregory continued his studies, gaining a knowledge of the mathematics of Descartes, Hudde, and Fermat. He also indulged his growing interests in natural philosophy: in Paris between August and December 1680, for example, he visited the observatory and sketched several of the instruments there. In London he was invited to a meeting of the Royal Society, and he made notes on Boyle's air-pump and Newton's reflecting telescope. He undoubtedly visited his uncle's friend and correspondent the mathematician John Collins. Gregory returned home in the summer of 1681 and spent most of the next two years there in close study of his uncle's papers.

Gregory may have met Pitcairne in Paris in 1680, or they may have met in Edinburgh between 1681 and 1683, or at an unknown earlier time. It seems probable that they had met by March 1683, when Pitcairne issued a public challenge to John Young, who had taught mathematics (without the title of professor) at the University of Edinburgh since James Gregorie's death. Young's unsatisfactory responses to Pitcairne led to his replacement by David Gregory, who was elected to his uncle's chair in October 1683. He was granted an MA degree by the university in the next month, and shortly thereafter delivered his inaugural address, 'De analyseos geometricae progressu et incrementis', a history of the progress of mathematics.

Gregory's first publication, Exercitatio geometrica de dimensione figurarum, appeared in 1684. It was based on his uncle's work on infinite series, and was reviewed by John Wallis in the Royal Society's Philosophical Transactions. Gregory sent a copy to Newton, acknowledging the latter's work on the calculus. This prompted Newton to begin to write up his own work. In 1685 Gregory and Pitcairne met the Scot John Craige, who soon after moved to Cambridge. Through Craige they learned more of Newton's work.

Gregory and Pitcairne were sharing lodgings in 1687 when Gregory received his copy of Newton's Principia. He wrote an effusive letter of praise to Newton, correctly calculating that Newton would prove to be a useful patron in the future. Gregory began a commentary, known as Notae in Isaaci Newtoni 'Principia', which he worked on intermittently for the rest of his life. Copies of the Notae circulated in manuscript, but it remained unpublished. The mathematician William Whiston (1667-1752) claimed that Gregory was the first to lecture publicly on the Newtonian philosophy (Biographia Britannica, 2366). However, very little Newtonian science appeared in Gregory's Edinburgh lecture course, though he did introduce a few students to Newtonian ideas, as evidenced by their essays.

The revolution of 1688 disrupted Gregory's life. As an Episcopalian and an associate of Pitcairne, a known Jacobite, Gregory was under suspicion, even though his personal politics seemed to be strictly pragmatic and his personal religion notable mainly for its lack of conviction. In 1690 the Scottish parliament empowered a university commission to enforce loyalty to the new regime by means of oaths. The commissioners had the power to eject unfit masters. Although Gregory refused the oaths, he was not ejected, probably because he had powerful patrons; it is unlikely that, as some sources have claimed, his reputation as a Newtonian had much influence on the commission. However, his position remained precarious, and when the Savilian professorship of astronomy at Oxford fell vacant in 1691, he mounted a campaign to attain it.

Gregory travelled to England in the summer of 1691, where he met Newton, Flamsteed, and Halley. He obtained the support of Newton and Flamsteed for the chair. Halley, his main rival, was passed over because of rumours of his irreligion; a later anecdote describes a Scot who travelled to London to meet Halley, the only man 'that has less religion than Dr Gregory' (Bodl. Oxf., MS Rawl. J).

Gregory was elected to the chair in December 1691 and took the degrees of MA and MD at Oxford in February 1692, when he was admitted a fellow of Balliol College. His degree theses, on optics, were drawn from his Edinburgh lectures on that topic. In his 'Tres lectiones cursoriae' he contrasted Galen's qualitative optics with his own, based on 'true mathematical principles' (Aberdeen University Library, MS 2206/8, fol. 1), and described the optic nerve in terms Newton had recently disclosed to Pitcairne. Gregory was very interested in medicine, as his papers and correspondence with Pitcairne indicate. A manuscript notebook survives (BL, Add. MS 29243) detailing his medical practice, which was confined to his friends and family but was more sophisticated than the usual lay medicine. He was elected an honorary fellow of the Edinburgh College of Physicians in 1705.

Gregory's inaugural lecture for the Savilian chair summarized the necessary relationship between astronomy and geometry, and heaped praise on English achievements in this area. As this lecture indicated, he gladly left troubled Scotland behind, though he continued to be interested and involved in Scottish politics. His father signed Kinnairdy over to him in 1690, and Gregory visited nearly every summer. Most of his family continued to reside in Scotland, and in 1695 he married Elizabeth Oliphant, of the Oliphants of Langtoun. Her brother Charles was an Edinburgh physician and one-time protégé of Pitcairne. The Gregorys had nine children, only two of whom--their eldest son, David Gregory (1695/6-1767), and third son, Charles--reached adulthood.

Gregory was elected a fellow of the Royal Society in 1692 and published several mathematical papers in the Philosophical Transactions. His Catoptricae et dioptricae sphaericae elementa, an edited version of his Edinburgh lectures on optics from the 1680s, appeared in 1695 (2nd edn, 1713; English trans., 1715; 2nd edn, ed. J. T. Desaguliers, 1735). It is notable for an appended remark that suggested the possibility of constructing an achromatic compound lens by employing lenses of different media, on the model of the crystalline and vitreous humours of the eye.

Gregory lectured conscientiously at Oxford, though less often than the Savilian statutes demanded. As in Edinburgh, his lectures emphasized fairly basic knowledge and seldom mentioned Newton's work. He was interested in the reform of mathematics teaching and drew up several papers on this topic, none of them published. He suggested that teaching be in English rather than Latin, and emphasized practical knowledge. He was a well-liked teacher and strongly influenced several of his students, including James and John Keill and John Freind. His work on practical geometry, composed in Edinburgh, was published by Colin Maclaurin in 1745 as A Treatise of Practical Geometry and remained a popular textbook, reaching a ninth edition in 1780.

Like many of his contemporaries, Gregory sought the prestige of an appointment at the royal court. With the support of Newton and Bishop Gilbert Burnet (a friend of his late uncle), he was named mathematics tutor in 1699 to the young duke of Gloucester, son of Princess Anne. Flamsteed also tried for the post; his disappointment caused his relationship with Gregory, already made difficult by the latter's closeness to Newton, to deteriorate further.

The death of the young duke in 1700 severed this promising tie to the court, but Gregory nevertheless moved to London about 1704, and lived at St John's Street, Long Ditch, Westminster. Newton obtained for him an appointment as overseer of the Scottish mint in 1707, following the union of parliaments. Gregory, a supporter of the union, supervised the reminting of Scottish coins to bring them up to the English standard, spending several months in Edinburgh. He helped to calculate the Equivalent, a payment to the Scottish Treasury to offset the expected loss in Scottish customs duties resulting from the Union.

In 1702 Gregory published his major work, Astronomiae physicae et geometricae elementa, the first textbook on astronomy to integrate Newton's gravitational theory with standard findings. It was dedicated to Prince George of Denmark. Newton contributed to the book the first publication of his lunar theory and a preface that asserted the antiquity of the concept of universal gravitation, known, he said, to the prisca sapientia. Gregory's work was an influential textbook, and was translated into English in 1715 (second editions of both Latin and English texts appeared in 1726). His predecessor in the Savilian chair, Edward Bernard, had initiated a project of new editions of ancient mathematical works, and Gregory edited a folio volume of Euclid's works in Greek and Latin (Euclidis quae supersunt omnia, 1703). He worked with Halley on an edition of Apollonius, but died before its completion.

Gregory's health was not strong in his later years, and he may have suffered from tuberculosis. In the autumn of 1708 he was encouraged to go to Bath to seek relief, 'a ridiculous advyse', according to his friend Pitcairne (Best of Our Owne, 54). Upon learning that his only daughter was ill with smallpox, he hastened to return to London after less than a week in Bath, but being ill himself was forced to stop at Maidenhead, where he sent for his friend Dr John Arbuthnot to attend him. Gregory died, soon after Arbuthnot's arrival, on 10 October 1708 at The Greyhound inn in Maidenhead. His daughter had meanwhile died of smallpox, and three of his sons were also ill. Gregory was buried in the churchyard at Maidenhead, and his widow later had a marble monument erected to his memory in St Mary's Church, Oxford. The monument incorrectly gave Gregory's date of birth as 1661 and of death as 1710.

Gregory was not a notable observational astronomer: he made only one recorded observation, and Flamsteed characterized him as a 'closet astronomer' (DNB). He was a skilled but not brilliant mathematician. In character he was ambitious but well liked by his friends, who included Arthur Charlett, Halley, Wallis, Aldrich, and Arbuthnot. His importance lay rather in his considerable talents as a correspondent, communicator, and teacher, particularly of Newtonian natural philosophy.

ANITA GUERRINI

Sources  
C. M. Eagles, 'The mathematical work of David Gregory, 1659-1708', PhD diss., U. Edin., 1977
A. G. Stewart, The academic Gregories (1901), 52-76
P. D. Lawrence and A. D. Molland, 'David Gregory's inaugural lecture', Notes and Records of the Royal Society, 25 (1970), 143-78
David Gregory, Isaac Newton, and their circle, ed. W. G. Hiscock (1937)
R. S. Westfall, Never at rest: a biography of Isaac Newton (1980)
The best of our owne: letters of Archibald Pitcairne, 1652-1713, ed. W. T. Johnston (1979)
A. Guerrini, 'The tory Newtonians: Gregory, Pitcairne, and their circle', Journal of British Studies, 25 (1986), 288-311
The correspondence of Isaac Newton, ed. H. G. Turnbull and others, 1-4 (1959-67)
A. Charlett, correspondence, Bodl. Oxf., MS Ballard 14
Biographia Britannica, or, The lives of the most eminent persons who have flourished in Great Britain and Ireland, 4 (1757), 2365-72
U. Aberdeen, MS 2206/8, MS 2206/46 B1
Bodl. Oxf., MS Rawl. J
DNB

Archives  
BL, medical notebook, Add. MS 29243
Christ Church Oxf., notes and tables
RS, corresp. and papers
U. Aberdeen L.
U. Edin. L., corresp. and papers
U. St Andr. L., treatises and lecture notes
University of Toronto |  BL, Sloane MSS, letters mainly to Sir Hans Sloane
CUL, letters to Sir Isaac Newton

Likenesses  
W. Townesend, monument, 1708, St Mary's Church, Oxford [see illus.]

Wealth at death  
£50 p.a. to wife for life; £330 each to four younger sons; £500 to daughter; remainder, incl. family possessions in Scotland, to eldest son: will, PRO, PROB 11/504, sig. 249


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