by Anita McConnell
© Oxford University Press 2004 All rights reserved
Machin, John (bap. 1686?, d. 1751), astronomer, was possibly the son of John and Mary Machin who was baptized on 17 October 1686 at St Botolph without Bishopsgate, London. Nothing is known of his early years or his education, but he was elected a fellow of the Royal Society on 30 November 1710 and served as its secretary from 1718 to 1747. He was on the society's committee set up to adjudicate the priority dispute between Newton and Leibnitz over the invention of the calculus, which vindicated Newton, and he was one of those charged to edit the relevant documents, published in 1712 as the Commercium epistolicum. His application for the professorship of astronomy at Gresham College in 1713 was naturally supported by Newton, who stated that he knew Machin to be proficient in Latin and mathematics, and that he had prepared Flamsteed's observations for the press, and also by the Savilian professor John Keill, Edmond Halley, and James Pound. He was duly appointed on 16 May 1713, and held the post until his death.
Machin was considered an able mathematician, and several of his papers were published in the Philosophical Transactions; however, his attempt to rectify Newton's lunar theory in his Laws of the Moon's Motion According to Gravity, which was appended to a 1729 translation of Newton's Principia, was considered a poor performance, while his computation of the value of π to 100 decimal places by Halley's method was merely a testimony to perseverance. Having made amendments to the lunar tables, he asserted unsuccessfully his claim to a share of the parliamentary reward for the discovery of longitude. He left unfinished a major work on lunar theory begun in 1717.
In October 1726 Machin was at Broxmouth, Roxburghshire, the seat of the duke of Roxburghe, where he observed a brilliant and spectacular aurora, later described to the Royal Society. On another occasion he took issue with the reasons given by Sir John Clerk for the ability of geese and other birds to migrate over vast distances, apparently without food or rest. Machin strenuously disputed Clerk's assertion that the birds flew at a great height to escape the friction of the air, and that they coasted as the earth rotated beneath them. In his later years Machin was in poor health and attended infrequently at the society; hence he was not re-elected in 1747. A resident of the parish of St Peter-le-Poer, Old Broad Street, he was unmarried, and his only relative was a second cousin, Mary Tasker. He died, aged sixty-four, in London, on 9 June 1751 and was buried at St Botolph without Bishopsgate on 12 June. He left no will and, as Mary Tasker renounced, the administration of his estate was granted to a creditor, John Thompson.
ANITA MCCONNELL
Sources
C. R. Weld, A history of the Royal Society, 2 vols. (1848), vol. 1, p. 410
Nichols, Illustrations, 4.23
BL, Add. MS 6194, 210-12
GM, 1st ser., 21 (1751), 284
London Magazine, 20 (1751), 284
Scots Magazine, 13 (1751), 309
S. P. Rigaud and S. J. Rigaud, eds., Correspondence of scientific men of the seventeenth century, 1 (1841), 280
C. Hutton, Tracts on mathematical and philosophical subjects, 1 (1812), 266
W. Jones, Synopsis palmariorum matheseos, or, A new introduction to the mathematics (1706), 243
Reliquiae Galeanae, or, Miscellaneous pieces by the late learned brothers Roger and Samuel Gale (1781), no. 2, pt 1 [3/2] of Bibliotheca topographica Britannica, ed. J. Nichols (1780-1800), 267
administration, PRO, PROB 6/127, fol. 227v
parish registers, St Botolph without Bishopsgate, London
DNB
Archives
BL, corresp. and papers
RS
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