John Tyndall (1820-1893), Irish physicist. Born in County Carlow, Ireland, Tyndall was trained as a draughtsman and surveyor. However, in 1848 he went to Germany to continue his education in physics. His early work was in diamagnetism, this attracted the attention of Faraday and in 1853 Tyndall was appointed professor of physics at the Royal Institution. His later work on the interaction of heat and the atmosphere was crucial to many later scientists - he discovered the Tyndall Effect (scattering of light by impurities in gas), the absorption of heat by the air and the identity of thermal infrared as a kind of light. Tyndall was also a talented mountaineer, powerful educator and staunch supporter of Darwin.