Alchemy was a medieval protoscience, or chemical philosophy, that aimed to discover the panacea for all ills, to concoct an elixir of longevity, to find a universal solvent, and to transmute base metals into gold. Of all those goals, transmutation seemed the most attainable, for sea salt, drawn from sea water by the sun or in the alchemist's workshop by fire, seemed to be a model of the magical process.
By 1800 the philosophies of alchemy had given way to the new science of chemistry. The English electro-chemist Humphrey Davy (1778-1829) isolated salt's components sodium (Na) in 1807, and Chlorine (Cl) in 1810.
Udo Becker, The Continuum Encyclopedia of Symbols, trans. Lance W. Garmer (New York: Continuum, 1994).
Robert Kraske, Crystals of Life: The Story of Salt (New York: Doubleday, 1968).
Jacques de Langre, Seasalt's Hidden Powers (Magalia, California: Happiness Press, 1994).