Dictionary of National Biography, 1885-1900/Earnshaw, Thomas
EARNSHAW, THOMAS (1749–1829), watchmaker, was born at Ashton-under-Lyne, Lancashire, on 4 Feb. 1749, and at the age of fourteen was bound apprentice to a watchmaker. He afterwards set up in business in London, and for many years had a shop at 119 High Holborn. He greatly improved and simplified Graham's ingenious transit clock at the Greenwich Observatory, and was the first who succeeded in making chronometers so simple and cheap as to be within the reach of private individuals. He was the inventor of the cylindrical balance spring, and of the detached detent escapement, though in the last he was anticipated in France by L. Berthoud. He was one of the competitors for the discovery of the longitude in 1793, when his cause was espoused by Maskelyne. His application was unsuccessful, but the commissioners granted him and John Arnold 3,000l. each for the improvements they had made in chronometers. Earnshaw wrote two pamphlets: 1. ‘Explanations of Timekeepers constructed by the Author and the late Mr. John Arnold. Published by order of the Commissioners of Longitude,’ 1806, 4to. 2. ‘Longitude: an Appeal to the Public, stating T. E.'s Claim to the Original Invention of the Improvements in his Timekeepers,’ 1808, 8vo.
He died on 1 March 1829 in Chenies Street, Bedford Square, aged 80. His portrait was engraved by S. Bellin, after Sir M. A. Shee.[Wood's Curiosities of Clocks and Watches, 1866; Cat. of Libr. and Mus. of the Company of Clockmakers (Guildhall, London), 1875, pp. 11, 99; Notes and Queries, 1885, 6th ser. xi. 472; Gent. Mag. 1829, pt. i. p. 283; Cat. of the Patent Office Library, 1881, i. 207; London Directories; Saunier's Modern Horology, p. 477.]