Dictionary of National Biography, 1885-1900/Conduitt, John
CONDUITT, JOHN (1688–1737), master of the mint, of Cranbury Park in HAmpshire, nephew by marriage of Sir Isaac Newton, in all probability the son of Leanard and Sarah Conduitt, was baptised at St. Paul's, Garden, 8 March 1688. He was admitted into Westminster School in June 1701, and in June 1706 was elected to Trinity College, Cambridge. After leaving the university he travelled for some time upon the continent. In 1711 he was judge-advocate with the British forces in Portugal, and in the following year was made captain in a regiment of dragoons serving in that country. In March 1715 he was elected member for Whitchurch, Hampshire, for which borough he continued to sit until, in 1734, he was returned for Southampton. On 20 Aug. 1717 he was married to Mrs. Katherine Barton, Newton's niece. The circumstances of this lady's acquaintance with Halifax belong more properly to the biography of the latter [see Montague, Charles, Earl Halifax]. They have been minutely investigated by Professor De Morgan in a special monograph (Newton, his Friend, and his Niece, 1885). The marriage appears to have been a very happy one, and Conduitt manifested an exemplary affection and respect for his great relative. Upon Newton's death on 20 March 1727, Conduitt succeeded him as master of the mint, having already, according to Hutton, relieved his uncle of the more onerous duties of the post for several years. It had nevertheless been offered to Dr. Samuel Chirke, who refused it as incompatible with his clerical duties. Conduitt appears to have procured a place in the mint for a relation of Chirke's, but Whiston emphatically contradicts the rumour that he compensation for waiving his claim. Conduitt's fitness for the office was shown by his 'Observations on the Present State of our Gold and Silver Coins,' an essay commended by Jevons as 'luminous, sound, and masterly.' It was written in 1730, and first published in 1774 from a manuscript copy formerly in the possession of Swift. The chief objects of the memoir, drawn up at a time when gold was falling in value and silver rising, were to advocate the coinage of the latter metal in preference to the former, and to recommend a reduction in the weight of the silver currency. It was also proposed to legalize the exportation of coin, on condition of the exporter having a corresponding quantity of bullion. The tract evinces great knowledge of the history of currency, and much care in experimental assaying. Swift had no doubt procured a copy on account of his interest in Irish currency matters, then and long afterwards a fertile source of anxiety to government. Archibishop Boulter's letters make frequent mention of Conduitt, especially of his plan for remedying the dearth of small change in Ireland by a copper coinage. Next to his labours as a financier and economist, Conduitt's chief title to remembrance is his contribution to the biography of his illustrious uncle. Shortly after Newton's death Conduitt drew up a memorial sketch for the use of Fontenelle, whose duty it was to pronounce Newton's eulogium as an associate of the French Academy of Sciences. It was published in Turner's 'Collections for the History of the Town and Soke of Grantham' (1806). The use made of it by Fontenelle was by no means satisfactory to Conduitt. 'I fear,' says he, 'he had neither abilities nor inclination to do justice to that great man, who has eclipsed the glory of their hero, Descartes.' He accordingly resolved to write Newton's life himself, and sent round a circular letter soliciting information, from which the above sentence is an extract. Eighteen months afterwards, however, he only says in a letter that he has some thoughts of writing Newton's biography. 'That he made the attempt,' says Sir David Brewster, 'appears from an indigestion. His mass of manuscript which he has left behind him, and which does not lead us to regret much that he abandoned his design. The materials, however, which he obtained from Mrs. Conduitt and from the friends of Newton then alive are of great value.' They are still in the possession of his descendants, the family of the Earl of Portsmouth, and were used by Brewster for his biogaphy of Newton. We have to thank Conduitt among other things for having preserved Newton's famous comparison of himself to 'a boy playing on the sea-shore and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, while the great ocean of truth lay all undiscovered before me.' Turnor's book also contains Conduitt's minute of a remarkable conversation with Newton on the exhaustion of the fuel of the sun, and its possible renovation by comets, which shows the interest he himself took in such questions. Conduitt died 23 May 1737, and was buried in Westminster Abbey on the right-hand side of Sir Isaac Newton. His only child, a daughter, married on 8 July 1740 Viscount Lymington, eldest son of the first Earl of Portsmouth. Their son succeeded as second Earl of Portsmouth.
[Brewster's Life of Newton; Chester's Registers of Westminster Abbey; Welch's Scholars of St. Peter's College, Westminster; Gent. Mag. vol. vii.; Turnor's Hist. of Grantham; Boulter's Letters to Ministers of State; Jevons's Investigations in Currency and Finance; De Morgan's Newton, his Friend and his Niece.]