warrant. 1  authorization, sanction, or justification. 2  something that serves to give reliable or formal assurance of something; guarantee, pledge, or security. 3  something considered as having the force of a guarantee or as being positive assurance of a thing: The cavalry and artillery were considered sure warrants of success.
Potassium metal was discovered in 1807 in England by Sir Humphry Davy, who derived it from caustic potash (KOH), by the use of electrolysis of the molten salt with the newly discovered voltaic pile. Before the 18th century, no distinction was made between potassium and sodium.
History and Uses: Radon was discovered by Friedrich Ernst Dorn, a German chemist, in 1900 while studying radium 's decay chain. Originally named niton after the Latin word for shining, nitens, radon has been known as radon since 1923. Today, radon is still primarily obtained through the decay of radium.