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Electrons and Ions
In Britain, Michael Faraday (1791-1867) had established the laws governing the way in which electric currents decompose (or break down) solutions containing chemical compounds.
These electrical currents caused atoms to become charged positively or negatively and to move in opposite directions: Faraday christened them ions (from the Greek word ionos, meaning wanderer).
However, it was not until 1874 that George Stoney (1826-1911), an Irish physicist, took a hint from the atomic theories of Dalton and suggested that electricity itself may also have an atomic structure. He proposed the name electron to describe this atom of electricity. Today, we accept the electron to be a negatively charged particle of matter, but Stoney originally thought of the electron simply as an electrical charge which could be either positive or negative. The electrons were concealed in some way within the atoms and only made their presence felt when the compounds were split into Faraday's ions.
Meanwhile other scientists in Germany had begun to investigate the conduction (or transmitting) of electricity in gases. As early as 1859, Heinrich Geissler (1814-79) demonstrated that when electricity was passed through a gas- at low pressure in a glass tube, the walls of the tube began to glow with a strange fluorescence.
Further work in this branch of physics by Faraday and William Crookes (1832-1919), an English chemist and physicist, finally led Professor J. J. Thomson (!856-1940) at Cambridge University to the conclusion that both positive and negative charges were produced when gases conducted electricity.
Thomson made a brave attempt to create a new model of the atom from the evidence now available. He suggested that the atom was a drop of matter which was positively charged, but contained an equal number of negatively charged electrons distributed evenly inside it, like currants in a bun.