CHAPTER VI
WATER
65. Destructive Action of Water. The action of water in stream and
sea, in springs and wells, is evident to all; but the activity of
ground water--that is, rain water which sinks into the soil and
remains there--is little known in general. The real activity of ground
water is due to its great solvent power; every time we put sugar into
tea or soap into water we are using water as a solvent. When rain
falls, it dissolves substances floating in the atmosphere, and when it
sinks into the ground and becomes ground water, it dissolves material
out of the rock which it encounters (Fig. 30). We know that water
contains some mineral matter, because kettles in which water is boiled
acquire in a short time a crust or coating on the inside. This crust
is due to the accumulation in the kettle of mineral matter which was
in solution in the water, but which was left behind when the water
evaporated. (See Section 25.)
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