firm was engaged in laying telegraph cables, principally in the east. On 25 Sept. 1868 Bright & Clark dissolved partnership, and Clark formed with Henry Charles Forde (1827–1897) the firm still known as Clark, Forde, & Taylor, of Great Winchester Street, E.G. This firm, mainly under Clark's direction, laid the triplicate cables between Suez, Aden, and Bombay, the duplicate cables between Madras and Penang, and between Singapore and Batavia. The firm also laid cables between Singapore and Nagasaki; England, Gibraltar, Malta, and the Levant; Durban and Delagoa Bay; five Atlantic cables beginning with that between Brest and Newfoundland in 1869; and the first South Atlantic cable from Pernambuco to St. Louis in Senegal.
Clark was also interested in other forms of engineering. His earliest patent (28 Jan. 1854) had been one for 'conveying letters or parcels between places by the pressure of air and vacuum.' A similar patent was taken out on 11 June 1857, and subsequently he constructed the 4 ft. 6 in. pneumatic tube between the General Post Office and Euston station. In 1874 he entered into partnership with John Standfield as an hydraulic and canal engineer; the works of the firm were at Grays, Essex, and it constructed numerous floating docks, notably those at Vladivostock, Hamburg, Havana, Stettin, and North Shields. He was also senior partner in the firm of Latimer Clark, Muirhead, & Co., formed in 1875 to manufacture electrical apparatus and machinery.
In 1870–1 Clark took a large part in founding the Society of Telegraph Engineers and Electricians (now the Institution of Electrical Engineers), and in 1874–5 he served as its fourth president. On 6 June 1889 he was elected F.R.S., and he was also fellow of the Royal Astronomical and Geographical Societies. To astronomy and photography he devoted much of his leisure; he assisted Sir George Biddell Airy [q. v. Suppl.] in 1857 to devise a method of indicating Greenwich mean time throughout the country, and in 1853 he invented a camera for taking stereoscopic pictures with a single lens (Journal of Photographic Soc. 21 May 1853).
Clark died, aged 76, on 30 Oct. 1898 at his residence, 31 The Grove, Boltons, S.W., and was buried at the Kensington parochial cemetery, near Hanwell. He was twice married and left issue. A portrait of him is reproduced in Bright's 'Life of Sir C. T. Bright' (ii. 19).
Besides numerous papers contributed to the 'Proceedings of the Institution of Civil Engineers' and to other scientific periodicals, of which a list is given in the 'Royal Society's Catalogue,' Clark was author of the following independent works: 1. 'An Elementary Treatise on Electrical Measurement,' 1868, 8vo; translated into French (Paris, 1872) and into Italian (Genoa, 1874). 2. (with Robert Sabine) 'Electrical Tables and Formulæ,' 1871, 8vo. 3. 'A Treatise on the Transit Instrument,' 1882, 8vo (reissued 1884 as 'A Manual of the Transit Instrument'). 4. (with Herbert Sadler) 'The Star Guide,' 1886, 8vo. 5. 'Dictionary of Metric and other useful Measures,' 1891, 8vo. 6. 'Memoir of Sir William Fothergill Cooke' [q. v.], 1895.
[Proc. Inst. Civil Engineers, cxxxvii. 418-23; Journal Instit. Electrical Engineers, 1898 pp. 646–7, 1899 pp. 666–72; Times, 1 Nov. 1898; Men of the Time, ed. 1891; Who's Who, 1898 (Suppl.); Smiles's Lives of the Engineers, iii. 428, 431, 437; Celebrities of the Day, 1881 (notice by J. T. Humphreys issued separately same year); Lists of the Royal Society; Ronalds's Cat, of Scientific Papers; Fleming Jenkin's Scientific Papers, ii. 207–8, 230, 237; Index of Patentees, 1852–88; E. B. Bright's Life of Sir C. T. Bright, 1899; Charles Bright's Submarine Telegraphy, 1898.]
CLARKE, JOHN SLEEPER (1833–1899), actor, of English extraction, was born in Baltimore, Maryland, on 3 Sept. 1833, educated for the American law, and entered the office of a Baltimore solicitor. He made his début on the stage in 1851 at the Howard Athenaeum, Boston, as Frank Harvey in 'Paul Pry;' on 28 Aug. 1852, at the Chesnut Street theatre, Philadelphia, played Soto in 'She would and she would not,' and became principal comedian at the Front Street theatre, Baltimore, and joint lessee of the Arch Street theatre in Philadelphia. In 1861 he acted at the Winter Garden theatre, New York, of which, till its destruction in 1867, he was joint lessee. In 1865, with his brother-in-law, Edwin Booth, he purchased the Walnut Street theatre, Philadelphia, and in 1866 he was for a short time lessee of the Boston theatre. He had also a share in other managements. His first appearance in London was made in October 1867 at the St. James's theatre as Major Wellington de Boots in Stirling Coyne's 'Everybody's Friend,' rewritten for him and called 'A Widow Hunt.' At the Princess's in February 1868 he was Salem Scudder in a revival of 'The Octoroon,' and later, at the Strand, was the first Young Gosling in 'Fox versus Goose.' On 26 July 1869 he was the first Babington Jones in John Brougham's 'Among the Breakers.' At the same house he also played Toodles, Dr. Pan-