Spring Water, in addition to the substances detected in rain water, generally contains a small portion of muriate of soda, and frequently other salts: but the larger springs are purer than the smaller ones; and those which occur in primitive countries, and in siliceous rocks, or beds of gravel, necessarily contain the least impregnation. An important practical distinction has been founded upon the fact, that the water of some springs dissolves soap, while that of others deconrposes and curdles it: the former has been termed soft, the latter hard, water. Soft water is a more powerful solvent of all vegetable matters, and is consequently to be preferred for domestic as well as medicinal purposes. The brewer knows well, from experience, how much more readily and copiously soft water will dissolve the extractive matter of his malt; and the housewife does not require to be told, that hard water is incapable of making good tea. Sulphate of lime is the salt which generally imparts the quality of hardness to water; and it has been said that its presence will sometimes occasion an uneasy sense of weight in a weak stomach.

The quantity of this salt varies considerably; but, in general, it appears that the proportion of five grains in a pint of water will constitute hardness, unfit for washing with soap, and for many other purposes of domestic use. Animals appear to be more sensible of the impurities of water than man. Horses, by an instinctive sagacity, always prefer soft water; and when, by necessity or inattention, they are confined to the use of that which is hard, their coats become rough and ill-conditioned, and they are frequently attacked with the gripes. Pigeons are also known to refuse hard, after they have been accustomed to soft water 1.

1 Hard water has certainly a tendency to produce disease in the spleen of certain animals, especially in sheep. This is the case on the eastern side of the island of Minorca, as we are informed by Cleghorn.