Potassium
symbol, K; at. wt., 39, a monad metallic element, discovered by Davy in 1807, and very widely diffused through the vegetable, mineral and animal kingdoms. It may be obtained by electrolysis, but is now produced in large quantity by distilling in an iron retort an intimate mixture of charcoal and carbonate of potassium, a condition readily obtained by igniting crude tartar in a covered crucible. It can only be preserved in the metallic state by immersing it in rock oil.