George Johnstone Stoney FRS (15 February 1826 – 5 July 1911) was an Irish physicist. He is most famous for introducing the term electron as the "fundamental unit quantity of electricity". He had introduced the concept, though not the word, as early as 1874, initially naming it "electrine", and the word itself came in 1891. He published around 75 scientific papers during his lifetime. Education and employment Stoney was born at Oakley Park, near Birr, County Offaly, in the Irish Midlands, the son of George Stoney (1792–) and Anne Blood (1801–1883). The Stoney family is an old-established Anglo-Irish family. He attended Trinity College Dublin, graduating with a B.A. degree in 1848. From 1848 to 1852 he worked as an astronomy assistant to William Parsons, 3rd Earl of Rosse at Birr Castle, County Offaly, where Parsons had built the world's largest telescope, the 72-inch Leviathan of Parsonstown. Simultaneously Stoney continued to study physics and mathematics and was awarded an M.A. by Trinity College Dublin in 1852. From 1852 to 1857, Stoney was professor of physics at Queen's College Galway. From 1857 to 1882, he was employed as Secretary of the Queen's University of Ireland, an administrative job based in Dublin. In the early 1880s, he moved to the post of superintendent of Civil Service Examinations in Ireland, a post he held until his retirement in 1893. In that year, he took up residence in London, England. Stoney died in 1911 at his home in Notting Hill, London. Stoney continued his independent scientific research throughout his decades of non-scientific employment duties in Dublin. He also served for decades as honorary secretary and then vice-president of the Royal Dublin Society, a scientific society modelled after the Royal Society of London, and after his move to London Stoney served on the council of that society too. Additionally, he intermittently served on scientific review committees of the British Association for the Advancement of Science from the early 1860s on. Scientific output Stoney published seventy-five scientific papers in a variety of journals, but chiefly in the journals of the Royal Dublin Society. He made significant contributions to cosmic physics and to the theory of gases. He estimated the number of molecules in a cubic millimetre of gas, at room temperature and pressure, from data obtained from the kinetic theory of gases. Stoney's most important scientific work was the conception and calculation of the magnitude of the