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.
Dr. Glenn Seaborg and Edwin McMillan, Joseph Kennedy, and Arthur Wahl are credited with the discovery of plutionium. Plutonium was chemically identified in February in 1941 by Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy, and Arthur C. Wahl at the Berkeley Laboratory of the University of California (United States). They synthesized and isolated it in December of 1940 after bombarding uranium with deuterons.