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The laws of electrolysis were discovered by Michael Faraday, in 1832-33. He introduced a number of new names, really due to Whewell, which are still used in describing the phenomena.
Conductors of electricity are of two kinds: (1) those which conduct the current without undergoing chemical change, and are simply heated by the current; metals and graphite belong to this class of metallic conductors: (2) those which are decomposed by the current, such as acidulated water, and solutions of salts, called electrolytes (Greek lysis, setting free). This name is now used to denote also the dissolved substances themselves; common salt and sulphuric acid are called electrolytes because when dissolved in water they form electrolytically conducting solutions. In electrolysis one portion of the electrolyte travels to the positive pole, or positive electrode (Greek hodos, an entrance), or anode (Greek ana, up); the other portion travels to the negative electrode, or cathode (Greek kata, down). The parts of the electrolyte which move to the electrodes are called ions (ίώυ, part of the verb ίέυαι, to go, used by Homer); the anions arrive at the anode and the cations at the cathode. No chemical action is perceptible in the body of the electrolyte, but only at the electrodes, since only at these are the ions moving through the liquid liberated.
 | Fig: Nomenclature of electrolysis |
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