The ordinary name for sulphate of magnesium ; so called because it occurs in a spring at Epsom in Surrey, from the water of which it was originally prepared. It is now manufactured from mountain limestone, the lime being separated by sulphuric acid. It is found native in America, and may be also prepared from sea-brine. It is used in medicine as a purgative. It has a bitter, saline, disagreeable taste, which may be somewhat relieved by adding a little lemon syrup.