John Tyndall FRS (/ˈtɪndəl/; 2 August 1820 – 4 December 1893) was a prominent 19th-century Irish physicist. His scientific fame arose in the 1850s from his study of diamagnetism. Later he made discoveries in the realms of infrared radiation and the physical properties of air, proving the connection between atmospheric CO2 and what is now known as the greenhouse effect in 1859.