Epsom Salt, or SULPHATE OF MAGNESIA, , was originally obtained by evaporating the waters of the springs at Epsom. It was soon found that sea-brine also contained large quantities, and the manufacture at Epsom was therefore given up. At present it is found native in various parts of America, and large quantities are manufactured near Genoa, by a chemical process, from a rock containing magnesia and sulphide of iron. In England, as well as in America, varieties of magnesian limestone are extensively treated with sulphuric acid for its production, with the result that the market is well supplied with this useful remedy.
Epsom salt forms small needle-like crystals, which have a bitter saline taste and neutral reaction. It is a well-known useful purgative medicine, acting as a refrigerant, and sometimes as a diuretic. Its disagreeable bitter taste may be relieved by the addition of a little sulphuric acid (as in Henry's solution) or syrup of lemon. It is given in doses of oz. to 1 oz. or more, but in every case it is of importance that plenty of water be drunk along with it (one or more tumblerfuls). See MAGNESIUM.