Stoney, George Johnstone (1826–1911)

Irish physicist. He is best known for introducing the term ‘electron’ into science, calculating an approximate value for the charge of this unit of negative electricity in 1874. He was also a pioneer in the field of spectroscopy, and made important contributions to the theory of gases.

Stoney was born in Oakley Park, King's County, the son of an impoverished landowner. He was educated at Trinity College, Dublin, became professor of natural philosophy at Queen's College, Galway in 1852. From 1857 onwards, he was engaged as an administrator, first at Queen's University, Belfast, and then (1882–93) as superintendent of civil service examinations, but continued his research in physics.

In 1868 he calculated the number of molecules in a cubic millimetre of gas from data obtained from the kinetic theory of gases. He proposed that light waves were produced by periodic ‘orbital motions’ within atoms or molecules. As early as 1874 he had calculated the magnitude of the electron. His 1891 paper to the Royal Dublin Society proposed the ‘electron’, also describing it as travelling in elliptical orbits in the molecule.

Stoney became a fellow of the Royal Society in 1861 and vice-president in 1898. He received the first Boyle Medal for scientific achievement awarded by the Royal Dublin Society in 1899.