The Irish physicist John Tyndall (1820-1893) is best known for his work on the scattering of light by atmospheric particles and on the absorption of infrared radiation by gases. He also did much to popularize science among laymen.

John Tyndall was born on Aug. 2, 1820, at Leighlin Bridge, near Carlow, Ireland, where his father was a constable. After a little formal schooling, he gained a practical education by working as a surveyor and engineer. He entered the University of Marburg, Germany, in 1848 and earned his doctorate 2 years later. His dissertation research interested Michael Faraday, who later brought him to the Royal Institution of London. In 1867 Tyndall succeeded Faraday as superintendent there. He retired in 1887.

Tyndall is noted for his study of the scattering of light by atmospheric particles, a phenomenon sometimes called the Tyndall effect. In 1869 he provided explanations for the color of the sun at the horizon and of clear skies; about 2 years later Lord Rayleigh provided the relevant theory. Tyndall showed that if broth was placed in air which was without scattering particles, the usual life forms did not develop. His work thus did much to invalidate the "spontaneous generation" theory of life.

Tyndall's studies of the transmission of infrared radiation through gases and vapors did much to clarify the nature of the absorption process and brought him the Rumford Medal in 1869.

In connection with consulting work on navigational aids Tyndall gave much attention to sound phenomena. This resulted in his interesting book On Sound (1867), written "to render the science of acoustics interesting to all intelligent persons including those who do not possess any special scientific culture." He wrote 15 other popular treatises, many of which are still enjoyable reading. "As a popular writer on the phenomena of physics he had no equal."

Tyndall's passion for justice was never better demonstrated than during the bitter scientific controversy of 1864-1866 concerning the priority rights of J. R. Mayer, whose cause Tyndall supported, as originator of the conservation-of-energy concept. Mention is also due his 1874 address at Belfast, in which he firmly advocated the right of science to follow its course without restrictions by dogma or theology, and in which he equally firmly denied that there was any basic conflict between science and religion.

Tyndall was an expert mountain climber and in 1861 made the first ascent of the Weisshorn. At the age of 56 he married the woman who, he said, "raised my ideal of the possibilities of human nature." He died at his home in Hindhead on Dec. 4, 1893.

Further Reading

• A full and interesting account of Tyndall is provided in A. S. Eve and C. H. Creasey, The Life and Work of John Tyndall (1945). Tyndall's life and contributions to science are discussed in James Gerald Crowther, Scientific Types (1970).
• John Tyndall, essays on a natural philosopher, Dublin: Royal Dublin Society, 1981.