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.
Krypton was discovered in Britain in 1898 by Sir William Ramsay, a Scottish chemist, and Morris Travers, an English chemist, in residue left from evaporating nearly all components of liquid air. Neon was discovered by a similar procedure by the same workers just a few weeks later.