HOW WATER GETS MIXED WITH LIME.
Throughout a very wide area of territory in the United States and Canada, limestones, or various forms of calcareous rocks, constitute the upper rock stratum immediately underlying the subsoil of the great agricultural regions. During the stupendous operations of Nature in building up this continent, the rocks have been subjected to vast disintegrating agencies: they have been torn and eroded by huge masses of ice; they have been burned by the rays of the unshadowed sun; fractured by the congealing power resulting from deep-searching frost; melted by water,—that most universal solvent in nature; then scattered far and wide by ice and flood. This process has been so complete, that, in the whole limestone territory, all the earth seems charged with lime. Limestones are very sparingly soluble in pure water; but the rain that falls from the clouds is not pure, but contains a charge of carbonic acid that acts chemically upon the lime, forming salts, which the water readily dissolves. Owing to this circumstance, there are few streams, and fewer wells, in the calcareous districts that are not contaminated with lime. The water that passes into streams, generally runs over surfaces that have been washed partly free from lime; and, in consequence of this, creeks and rivers are not so badly tainted with lime-salts as the water in wells that stands saturating the rocks. The appearance or taste of water gives no indication of the quantity of lime held in solution; for the ice-cold well, or sparkling spring, that supplies water so pleasant to drink, may yield so much lime-salts that the water would be ruinous to sheets and flues when used for boiler purposes.