Daniell, John Frederic (1790-1845)

British chemist and meteorologist who invented a primary electrical cell 1836. The Daniell cell consists of a central zinc cathode dipping into a porous pot containing zinc sulphate solution. The porous pot is, in turn, immersed in a solution of copper sulphate contained in a copper can, which acts as the cell's anode. The use of a porous barrier prevents polarization (the covering of the anode with small bubbles of hydrogen gas) and allows the cell to generate a continuous current of electricity. The Daniell cell was the first reliable source of direct-current electricity. Daniell was born in London and privately educated. He was the first professor of chemistry at King's College, London, 1831-45. Daniell's other work included the development of improved processes for sugar manufacturing; investigations into gas generation by the distillation of resin dissolved in turpentine; and inventing a new type of dew-point hygrometer for measuring humidity (1820) and a pyrometer for measuring the temperatures of furnaces (1830). He also studied the behaviour of the Earth's atmosphere; gave an explanation of trade winds; researched into the meteorological effects of solar radiation and of the cooling of the Earth; suggested improvements for several meteorological instruments; and pointed out the importance of humidity in the management of greenhouses.