Clark, Josiah Latimer (1822–1898)

English engineer. He developed a system of enclosing underground wires by means of gutta-percha coating, worked out how to send messages by the pneumatic tube, and invented the double-cap invert insulator and the Clark cell. He also invented Clark's compound, a mixture of asphalt, hemp, and silica, for covering submarine cables.

Clark was born in Great Marlow, Buckinghamshire. He took a junior position on the construction of the Britannia tubular bridge, after which he became assistant engineer to the Electric Telegraph Company, with which he remained till 1870. He published several works, including Electrical Tables and Formulae (1871) and a Dictionary of Metric and Other Useful Measures (1891).