Saline compounds of magnesia

1320. The saline compounds of magnesia will require very little discussion with regard to their uses as manures. In combination with sulphuric acid, magnesia forms a soluble salt, well known under the name of Epsom salts. This substance has been found of use as a manure; but it is not found in nature in sufficient abundance, nor is it capable of being made by art sufficiently cheap, to be of useful application in the common course of culture.