George Johnstone Stoney

George Johnstone Stoney (* February 15, 1826 in Oakley Park, County Offaly, Ireland, † July 5, 1911 in London) was an Irish physicist. He gave the name of the elementary charge electron.

Stoney attended Trinity College in Dublin and was then assistant professor at the observatory of Lord Rosse at Birr. Later he was a professor of physics (Natural Philosophy) at Queens College, Galway ( National University of Ireland, Galway ), and was afterwards at Queen's University in Dublin, where he was secretary of the administrative center of the Queen's Colleges.

1874 Stoney struck before the existence of electric charge carriers uniformly sized cargo that should be associated with the atoms. From the electrolysis he derived first estimates of their charge, but was thus too low by a factor of 20. He made initial proposals at the meeting of the British Association in Belfast in 1874 ( On the physical units of Nature, published in 1881 ) and then in 1891 in the Trans Royal Dublin Society ( Volume 4, p 583 ), where he was also the name electron suggested. One possible reason for the choice of name was that electron, the Greek word for amber, the material on which for the first time electrostatic phenomena were observed. In his work of 1874 he made ​​the first proposal for a system of units Natural units, which it is the electron charge, the gravitational constant and the speed of light based on put as constants of nature.

The electron was first identified in 1897 by Joseph John Thomson Elementary ( he called it only corpuscule ), its electric charge determined in 1907 by Robert Millikan. The electron charge, known as the smallest free -occurring charge Quantum also elementary charge, is 1.602 · 10-19 C ( coulombs).

Stoney's determination of the elementary charge was in connection with his experiments, the Avogadro constant (or the Faraday constant ) to determine ( at the same time as Johann Josef Loschmidt and Lord Kelvin).

Stoney also dealt with spectroscopy. He was looking for a splitting of spectral lines in a magnetic field, but could be demonstrated until 1896 by Pieter Zeeman, and he took some of the laws anticipate that Johann Jakob Balmer 1885 took place in the spectrum of hydrogen ( Balmer series). He also constructed a heliostat.