Tyndall, John (tĭnˈdəl) [key], 1820–93, British physicist, b. Ireland. He became (1853) professor of natural philosophy at the Royal Institution and in 1867 succeeded Michael Faraday, his friend and colleague, as superintendent there. His chief researches were in the fields of light, sound, and radiant heat. He made significant studies of Alpine glaciers. He was known as a lecturer and writer, and his gifted expositions of science for the layman were widely translated. The Tyndall effect (see colloid) is named for him.