Tyndall , John

(1820–1893) British physicist

Tyndall was born at Carlow (now in the Republic of Ireland) and after leaving school began work as a draftsman and civil engineer in the Irish Ordnance Survey. He later became a railway engineer for a Manchester firm. His drive for knowledge caused him to read widely and attend whatever public lectures he could. In 1847 he became a teacher of mathematics, surveying, and engineering physics at the Quaker school, Queenwood College, Hampshire.

The following year Tyndall entered the University of Marburg, Germany, to study mathematics, physics, and chemistry; after graduating in 1850 he worked in H.G. Magnus's laboratory in Berlin on diamagnetism. He was appointed professor of natural philosophy at the Royal Institution in 1853 and became a colleague and admirer of Michael Faraday; he succeeded Faraday as director of the Royal Institution in 1867 and held this position until his retirement in 1887.

Tyndall's activities were many-sided. His chief scientific work is considered to be his researches on radiant heat; these included measurements of the transmission of radiant heat through gases and vapors published in a series of papers starting in 1859. But he is perhaps better known for his investigations on the behavior of light beams passing through various substances; he gave his name to the Tyndall effect – the scattering of light by particles of matter in its path, thus making the light beam visible – which he discovered in 1859. Tyndall elucidated the blue of the sky following the work of John Rayleigh on the scattering of light. He also discovered the precipitation of organic vapors by means of light, examined the opacity of the air for sound in connection with lighthouses and siren work, demonstrated that dust in the atmosphere contained microorganisms, and verified that germ-free air did not initiate putrefaction.

Tyndall was especially noted in his day as a great popularizer of science and advocate of scientific education, rather than as a great scientist. Among his many books for the nonspecialist the famousHeat Considered as a Mode of Motion (1863), the first popular exposition of the mechanical theory of heat, went through numerous editions. He was a member of the ‘X’ Club, a group of prominent British scientists formed to ensure that the claims of science and scientific education were kept before the government of the day. He also helped to inaugurate the British scientific journal Nature. In 1872 and 1873 he undertook public lecture tours in America, giving the proceeds to a trust set up to benefit American science.

Tyndall died in 1893, accidentally poisoned by his wife with an overdose of chloral hydrate. “You have killed your John,” he is alleged to have told her shortly before he died the following day. Louisa Tyndall lived another 47 years.