John Frederic Daniell (March 12, 1790 - March 13, 1845) was an English chemist and physicist.
Daniell was born in London, 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). He also invented the dew-point hygrometer known by his name (Quar. Journ. Sci., 1820), and a register pyrometer (Phil. Trans., 1830); and in 1830 he erected in the hall of the Royal Society a water-barometer, with which he carried out a large number of observations (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 Meteorological Essays (1823), an Essay on Artificial Climate considered in its Applications to Horticulture (1824), which showed the necessity of a humid atmosphere in hothouses devoted to tropical plants, and an Introduction to the Study of Chemical Philosophy (1839).
He died suddenly of apoplexy in London, while attending a meeting of the council of the Royal Society, of which he became a fellow in 1813 and foreign secretary in 1839.