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CHAP. I.

OF SOILS AND MANURES.

SECTION I.

OF SOILS.

LAND, considered as the basis of vegeta-tion, is called soil.

Soils consist of different combinations of twoor more of the four primitive earths, namely,the calcareous (which I sometimes call mildcalx) magnesia, argill, and the silicious. Fora more accurate description of these I mustrefer to books of mineralogy; and shall onlyremark, that by calcareous earths are meantchalk, and all stones that burn to lime. Theyare easily distinguished by their property of ef-fervescing with acids.

Magnesia is never found alone; its distin-guishing character consists in affording a bittersalt, generally called Epsom Salt , when com-bined with the vitriolic acid.

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