Frankland, Sir Edward, 1825-99, English chemist. He studied under Bunsen and Liebig and taught at several English institutions. In working on the synthesis and isolation of compounds he evolved the theory of valence. He made studies of water purification; of flame and luminosity with John Tyndall; of gases with J. N. Lockyer, with whom he discovered helium; and of the chemistry of foods. His work on water purification was continued by his son, Percy Faraday Frankland, 1858-1946, also a chemist, who with his wife, Grace Toynbee Frankland, conducted bacteriological studies. He and his wife wrote Micro-organisms in Water (1894) and Pasteur (1898).