Its existence as salt (sodium chloride), "soda ash" or "mineral alkali" (sodium carbonate), lye or "caustic soda" (sodium hydroxide), etc., had long been known, but it was not isolated as an element until 1807, by Sir Humphrey Davy. | Its existence as salt (sodium chloride), "soda ash" or "mineral alkali" (sodium carbonate), lye or "caustic soda" (sodium hydroxide), etc., had long been known, but it was not isolated as an element until 1807, by Sir Humphrey Davy. |