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The two great divisions of salts are, into acids and alkalis. The first of these are known by their peculiar taste, which are called acid or sour. They are not found in a solid form; neither are any of them, except the acids of vitriol, of tartar, of phosphorus, and of borax, capable of being reduced to solidity.
The others, when highly concentrated, that is, brought to the utmost degree of strength of which they are capable, always become an invisible vapour, permanently elastic, until it comes in contact with water, or some other substance with which they are capable of uniting.
For such acids the name of salts seem less proper, as we can scarcely say that a vapour which is already much more fluid than water can be dissolved in that element.
Both vegetable and mineral alkali appear to be composed of an exceedingly caustic
