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Gregory, Olinthus Gilbertlocked

  • Alexander Gordon
  • , revised by Ben Marsden

Olinthus Gilbert Gregory (1774–1841)

by Thomson, pubd 1823 (after Derby)

Gregory, Olinthus Gilbert (1774–1841), mathematician, was born on 29 January 1774 at Yaxley, Huntingdonshire, of unknown parentage. For more than ten years he studied intensively at the local boarding-school of the Leicester botanist and mathematician Richard Weston. At nineteen he secured the advice of patron John Joshua Proby, earl of Carysfort, before publishing Lessons, Astronomical and Philosophical … Interspersed with Moral Reflections (1793, revised 6th edn 1824), a work of natural theology for children. In 1794 Weston introduced Gregory as a mathematical problem solver to the annual Ladies' Diary. An unpublished treatise on the sliding rule, composed when he was twenty, brought him to the attention of Charles Hutton.

In 1794 or 1795 Gregory's friendship with J. S. Copley and other distinguished Cambridge students encouraged thoughts of a college career. These aspirations subsided when he absorbed William Frend's arguments and briefly adopted Socinianism. Thereafter, wary of religious hubris, he returned to the gospels for spiritual guidance; following Hartley he opposed subscription to articles of religion, and also matriculation. About 1798 he nevertheless settled in Cambridge where he worked for a few months as sub-editor of the Cambridge Intelligencer under Benjamin Flower. He abandoned journalism, began to teach mathematics in the town and university, and for about a year kept a bookshop.

A Treatise on Astronomy (1802), hastily written in the spring of 1801 and dedicated to Hutton, brought him into public notice. With the death of Charles Wildbore the Stationers' Company employed him to edit the Gentleman's Diary (1802–19) and one of their almanacs. From 1818 he edited the companion Ladies' Diary, managed White's Ephemeris, and, replacing Hutton, undertook the general superintendence of all the Stationers' almanacs and their astronomical calculations. Like his predecessor, Gregory used this key position to foster provincial mathematical talent. Hutton ensured that Gregory filled the new post of second mathematical master (December 1802) at the Royal Military Academy, then expanding with the growth of the Royal Artillery after the union with Ireland. From Woolwich Gregory marketed the Astronomy, his comprehensive, copiously illustrated, and highly successful Treatise of Mechanics (3 vols., 1806), and his annotated work, dedicated to Carysfort, An Elementary Treatise on Natural Philosophy (2 vols., 1807), from the French original by René Just Haüy, as together forming a complete course of natural philosophy; the Mechanics was used as a class book at West Point during the 1830s. Marischal College, Aberdeen, awarded him an honorary AM (1806) and an LLD (1808). The doctorate was a response to Gregory's gift of the opening volume of a vastly ambitious survey of human genius, learning, and industry, the Pantologia (12 vols., 1808–13).

As a versatile mathematical practitioner, Gregory advised technical publishers, negotiated with the Surrey Institution to give lectures on the mechanical part of experimental philosophy (1812), revised and extended Hutton's works (the famous Course of Mathematics of 1811 and other mathematical textbooks, dictionaries, and tables), composed a trigonometry primer (1816), and prepared a topical dissertation on weights and measures (1816). Although looking back to Newton and Desaguliers in his early writings, Gregory was well aware of the French theoretical engineering of Monge, Hachette, and Navier. Thus, in 1803 and 1804, he translated papers for Hutton's voluminous abridgement of the early Philosophical Transactions, while in the first volumes of the Retrospect of Philosophical, Mechanical, Chemical, and Agricultural Discoveries (8 vols., 1806–15), he reviewed critically the most recent British and foreign papers and inventions.

Woolwich offered Gregory facilities for large-scale collaborative investigations, and a stronghold from which to snipe at the Royal Society. His dissertations on the trigonometrical survey (1815) doubled as a defence of Thomas Colby and the academy's Lieutenant-Governor William Mudge from Royal Society criticism. At Woolwich Gregory and Mudge responded to the select committee of artillery officers by measuring the velocity of projectiles using a vast ballistic pendulum (1815–17); an excursion to the Shetlands with Colby to determine the shape of the earth by means of astronomical observations and pendulum experiments (1817) ended acrimoniously when Gregory quarrelled with his French collaborator Biot. Experimenting again with mortars, guns, and muskets, Gregory accurately determined the velocity of sound (1823).

Gregory was an active institutional actor. He was a lecturer on ballistics, a vice-president (to Carysfort's president), and an anniversary orator (1817) for the short-lived Philosophical Society of London. After that society's collapse, he published, anonymously, a scathing exposé of the Royal Society presidency of Hutton's bête noir, Sir Joseph Banks (1820). Thus irrevocably allied to British scientific reformers, he worked alongside Babbage, Herschel, and Millington as a founder (1820), secretary (1824–8), and vice-president (1829–30) of the Astronomical Society. As an honorary member of the Institution of Civil Engineers (1824) he heeded Henry Brougham's call and compiled a commonplace book of Mathematics for Practical Men (1825, 4th revised edn 1862) designed for the institution's younger members. He was recruited as an honorary member to literary, philosophical, statistical, and antiquarian societies in Newcastle, Bristol, Cambridge, Dijon, Paris, and New York. His last public address (1839) was to the Woolwich Institution, of which he had been elected president on its formation.

From the age of seven Gregory had scoured works of mathematics, universal grammar, and ancient and modern philosophy for rational solutions to profound metaphysical questions (the abstract nature of eternity, and of simple duration considered as an attribute of the Deity). In adulthood he toyed with Unitarianism, then regained his belief in the Trinity, only to abandon thoughts of becoming a minister when he concluded that both the discipline of the Episcopal church and the democratic government of the orthodox dissenting churches deviated greatly from the primitive pattern. His Letters to a Friend on the Evidences, Doctrines, and Duties of the Christian Religion (2 vols., 1811), written at the height of the evangelical revival, went through numerous editions, were abridged for the Religious Tract Society (1841), attracted heated debate in several languages, and won Gregory the patronage of William Wilberforce. The Letters were written, in part, for the religious instruction of his children, the offspring of his first marriage, on 20 December 1809, to Miss Beddome. One daughter became an ardent Unitarian; a son, Charles Hutton Gregory, became an eminent engineer; a second son was drowned in the Thames shortly before Gregory's death. The identity of his second wife is unknown.

Gregory was active in the formation (1812) of the Blackheath Auxiliary Bible Society and twice addressed its annual meetings (1815, 1816). As John Bonnycastle's successor in the Woolwich mathematics chair (May 1821), and as a prominent dissenter, he was one of the projectors of the non-sectarian London University. His name was inscribed on the foundation stone laid in Gower Street on 30 April 1827. Gregory was a frequent contributor to contemporary reviews and magazines. He composed biographical memoirs of his mentor, Hutton (1823), of the preacher and polymathic co-editor of the Pantologia, John Mason Good (1828), and of his Cambridge friend, the distinguished Baptist theologian Robert Hall, whose works he also edited (1832).

Gregory retired from his chair in June 1838, after a decade of debilitating illness. A farewell address on the acquisition of knowledge (1838) and a collection of hints for teachers of elementary mathematics (1840) distilled the pedagogic wisdom of forty years. The Stationers had allotted him a substantial annual pension. He died at his home on Woolwich Common on 2 February 1841. He was survived by his second wife. Capel Molyneux saw in Gregory's life 'a conclusive and valuable testimony … that true philosophy [science] and true religion are not incompatible' (Molyneux, 17).


  • ‘Memoir of Olinthus Gregory … professor of mathematics, Royal Military Academy, Woolwich’, Imperial Magazine, 5 (1823), 777–92
  • The Times (6 Feb 1841)
  • GM, 2nd ser., 15 (1841), 438–9
  • Monthly Notices of the Astronomical Society of London, 5 (1839–43), 81–2
  • C. Molyneux, A sermon occasioned by the death of Olinthus Gregory (1841)
  • D. P. Miller, ‘Between hostile camps: Sir Humphry Davy's presidency of the Royal Society of London, 1820–1827’, British Journal for the History of Science, 16 (1983), 1–47
  • [J. Watkins and F. Shoberl], A biographical dictionary of the living authors of Great Britain and Ireland (1816)
  • W. Jerdan, National portrait gallery of illustrious and eminent personages of the nineteenth century, with memoires, 5 vols. (1830–34)
  • W. C. Taylor, The national portrait gallery of illustrious and eminent personages, chiefly of the nineteenth century: with memoirs, 4 vols. in 2 [1846–8]
  • F. K. Brown, Fathers of the Victorians: the age of Wilberforce (1961)
  • D. P. Miller, ‘The revival of the physical sciences in Britain, 1815–1840’, Osiris, 2nd ser., 2 (1986), 107–34
  • Gregory to unnamed correspondent, 7 April 1812, Wellcome L., WMS/ALS, Olinthus Gregory dossier
  • private information (1890)
  • private information (2004)
  • d. cert.


  • RAS, RAS letters
  • Royal Artillery Institution, Woolwich, London, papers
  • BL, Babbage MSS, Add. MSS 16947, fol. 42, 34536, fol. 13
  • BL, Charles Blacker Vignoles MSS, Add. MS 40210, fol. 405
  • Bodl. Oxf., Wilberforce MSS
  • Inst. CE, membership records
  • Portsmouth Central Library, Charles Blacker Vignoles MSS
  • RAS, William Herschel MSS, 13.G.21 [microfilm]
  • RS, J. F. W. Herschel MSS
  • RS, John Lubbock MSS
  • Smithsonian Institution, Washington, DC, Dibner Library of the History of Science and Technology, Dibner collection
  • Wellcome L., Pettigrew MSS


  • Thomson, stipple, pubd 1823 (after Derby), NPG [see illus.]
  • H. Robinson, stipple, 1834 (after R. Evans), BM, NPG; repro. in W. Jerdan, National portrait gallery
Gentleman's Magazine
Wellcome Library for the History and Understanding of Medicine, London
R. Watt, , 4 vols. (1824); repr. (1963), (1964), (1965), (1990), (1995)