DANIELL, JOHN FREDERIC English chemist and physicist, was born in London on March 12, 1790, and in 1831 became the first professor of chemistry at the newly founded King's College, London. His name is best known for his invention of the Daniell cell (Phil. Trans., 1836; see BATTERY), still extensively used for telegraphic and other purposes. He also invented the dew-point hygrometer known by his name (Quar. Journ. Sci., 182o), and a register pyrometer (Phil. Trans., 183o) ; and in 183o he erected in the hall of the Royal Society a water barometer, with which he carried out a large number of observa tions (Phil. Trans., 1832). A process devised by him for the manufacture of illuminating gas from turpentine and resin was in use in New York for a time. His publications include Meteoro logical Essays (1823), an Essay on Artificial Climate considered in its Applications to Horticulture (1824), which showed the neces sity of a humid atmosphere in hothouses devoted to tropical plants, and an Introduction to the Study of Chemical Philosophy (1839). He died suddenly on March 13, 1845, in London, whiie attending a meeting of the council of the Royal Society, of which he became a fellow in 1813 and foreign secretary in 1839.