Sulphate of magnesia having cathartic qualities; -- originally
prepared by boiling down the mineral waters at Epsom, England, --
whence the name; afterwards prepared from sea water; but now from
certain minerals, as from siliceous hydrate of magnesia.
The chloride of sodium, a substance used for seasoning food,
for the preservation of meat, etc. It is found native in the earth, and
is also produced, by evaporation and crystallization, from sea water
and other water impregnated with saline particles.