BITTERN (from "bitter"), the mother liquor obtained from sea-water or brines after the separation of the sodium chloride (common salt) by crystallization. It contains various magne sium salts (sulphate, chloride, bromide and iodide) and is em ployed commercially for the manufacture of Epsom salts (mag nesium sulphate) and bromine. The same term is applied to a mixture of quassia, iron sulphate, cocculus indices, liquorice, etc., used in adulterating beer.