Publication: Dictionary of National Biography Supplement
CLARK, LATIMER (1822-1898), whose full name was JOSIAH LATIMER CLARK, engineer, was horn at Great Marlow, Buckinghamshire, on 10 March 1822.
His elder brother, EDWIN CLARK (1814-1894), after acting as mathematical master at Brook Green, and then as a surveyor in the west of England, came to London in 1846 and formed the acquaintance of Robert Stephenson [q. v.| (see Times, 26 Oct. 1891). Stephenson appointed him superintending engineer of the Menai Straits bridge, which was opened on 5 March 1860, and in that year Clark published 'The Britannia and Conway Tubular Bridges' (2 vols. 8vo; an atlas formed a third volume). In August 1850 he became engineer to the Electric and International Telegraph Company, and three months later he toot out his first patent (12 Nov.) for 'electric telegraphs and apparatus connected therewith.' From that time he divided his time between electric and hydraulic engineering. On 4 Feb. 1856 he took out a patent for 'suspending insulated electric telegraph wires,' but most of his patents (e.g. 19 Jan. 1857, 19 Sept, 1865, 6 May 1870, 9 Jan. 1872, and 18 Feb. 1873) were for improvements in dry docks and floating docks, in the methods of lifting ships out of the water for repairs, and for constructing piers. He was elected a member of the Institution of Civil Engineers on 3 Dec. 1850, was awarded a Telford medal in I860 for his paper "On the Hydraulic Lift Graving Dock," and a Watt medal in 1808 for his papers on 'The Durability of Materials' (Proc. Inst. Civil Engineers, x. 57, xxvi. 121, 138, xxviii. 161, 178). He contributed numerous papers to the ' Proceedings of the Institute of Civil Engineers," and in 1878 published 'A Visit to South America ' (London, 8vo). He died at Cromwell House, Marlow, on 22 Oct. 1894 (Times, 24 Oct. 1894).
Latimer Clark began life as a chemist and spent some years with a firm of chemical manufacturers at Dublin ; but in 1847 he commenced railway surveying, and in 1848 was appointed assistant engineer under his brother to the Menai Straits bridge. He helped his brother in preparing his book on that bridge and contributed to it an account of the tides in the Menai Straits. In August 1850 he became assistant engineer under his brother to the Electric and International Telegraph Company. Some ten years later he succeeded his brother as chief engineer to the company, and held this post until the various telegraphic systems were taken over by the government in 1870. Clark introduced several improvements in the telegraph system, notably by coating the gutta percha enclosing underground wires with a solution which prevented its decay; he also invented the insulator known as the 'double-cap invert,' and the battery now known as the Clark cell (Phil. Trans. 1874, p. 1; American Journal of Science, cxxxviii. 402; PREECE and SIVEWRIGHT, Electric Telegraphy, 1899, pp. 41, 483). He took out many patents for these inventions—the first on 29 Nov. 1856, four in 1858, and others in 1859, 19 Nov. I860, 30 June 1870, and 14 Sept. 1871. In 1853 he proved that the rate of the electric current is constant and irrespective of pressure; his experiments were repeated before Faraday (FAKADAY, Experimental Researches, pp. 608-17), and in 1855 Clark published his results in a pamphlet on 'Experimental Investigation of the Laws which govern the Propagation of the Electric Current in Submarine Telegraph Cables.' On 13 April 1858 he became an associate, and on 19 Nov. 1861 a member, of the Institution of Civil Engineers ; he was for some months engineer to the Atlantic Cable Company, and in 1860 served on the committee appointed by government to inquire into the subject of submarine telegraphy.
In 1861 Clark entered into partnership with Sir Charles Tilston Bright [q. v. Suppl.], and their joint paper