CLARK, JOSIAH LATIMER (1822-1898), English engi neer and electrician, was born on March 1o, 1822, at Great Mar low, Bucks. In 1848 he became assistant engineer at the Menai Straits bridge under his elder brother Edwin (1814-94), the in ventor of the Clark hydraulic lift graving dock. Two years later, when his brother was appointed engineer to the Electric Tele graph Company, he again acted as his assistant, and subsequently succeeded him as chief engineer. In 1854 he took out a patent "for conveying letters or parcels between places by the pressure of air and vacuum," and later was concerned in the construction of a large pneumatic despatch tube between the general post office and Euston station, London. He also experimented on the propa gation of the electric current in submarine cables, and in 1859 he was a member of the committee which was appointed by the Government to consider the numerous failures of submarine cable enterprises. Latimer Clark paid much attention to the sub ject of electrical measurement, and besides designing various im provements in method and apparatus and inventing the Clark standard cell, he took a leading part in the movement for the systematization of electrical standards, which was inaugurated by the paper which he and Sir C. T. Bright read on the question before the British Association in 1861. With Bright also he de vised improvements in the insulation of submarine cables. He was a member of several firms engaged in laying submarine cables, in manufacturing electrical appliances, and in hydraulic engineering. He died in London on Oct. 3o, 1898. His chief works are : Elec trical Measurement (1868) ; and, with R. Sabine, Electrical Tables and Formulae for Operators in Submarine Cables (1871).