[f. BITTER a. (perh. dial. form of bittering).]
1. The mother water or lye which remains after the crystallization of common salt from sea-water or the brine of salt-springs. It contains sulphate and chloride of magnesium, bromine, iodine, etc.
1682. J. Collins, Salt in Eng., 54. The Bittern in Refining of French Salt, is a Liquor separated from it, that resembles Sack in Colour, but Gall in Tast.
1810. Henry, Elem. Chem., I. 415. The uncrystallizable part called bittern.
1879. G. Gladstone, Salt, in Cassell’s Techn. Educ., IV. 354. The deliquescent and non-crystallisable ingredients constitute … the bitterns which drain from the stacks of sea salt.
1883. Knowledge, 15 June, 354/2. The … bittern is employed as a source from which other substances are prepared, as … bromine.
b. attrib.
1755. Hales, in Phil. Trans., XLIX. 327. The saline spirit arises chiefly from the bittern salt.
1772. Monro, ibid., LXII. 30. Sea salt mixed with a bittern and oily matter.
2. A name applied to bitter substances used for different purposes; spec. (also bitterin, bittering) an old trade name for a mixture of quassia and other drugs employed in adulterating beer.
1775. Adair, Amer. Ind., 403. The water is sufficiently impregnated with the intoxicating bittern.
