f the dish which
contains them.

If water contracted in freezing, ice would be heavier than water and
would sink in ponds and lakes as fast as it formed, and our streams
and ponds would become masses of solid ice, killing all animal and
plant life. But the ice is lighter than water and floats on top, and
animals in the water beneath are as free to live and swim as they were
in the warm sunny days of summer. The most severe winter cannot freeze
a deep lake solid, and in the coldest weather a hole made in the ice
will show water beneath the surface. Our ice boats cut and break the
ice of the river, and through the water beneath our boats daily ply
their way to and fro, independent of winter and its blighting blasts.

While most of us are familiar with the bursting of water pipes on a
cold night, few of us realize the influence which freezing water
exerts on the character of the land around us.

Water sinks into the ground and, on the approach of winter, freezes,
expanding about one tenth of its volume; the expanding ice pushes the
earth aside, the force in some cases being sufficient to dislodge even
huge rocks. In the early days in New England it was said by the
farmers that "rocks grew," because fields cleared of stones in the
fall became rock covered with the approach of spring; the rocks and
stones hidden underground and unseen in the fall were forced to the
surface by the winter's expansion. We have all seen fence posts and
bricks pushed out of place because of the heaving of the soil beneath
them. Often householders must relay their pavements and walks because
of the damage done by freezing water.

The most conspicuous effect of the expansive power of freezing water
is seen in rocky or mountainous regions (Fig. 21). Water easily finds
entrance into the cracks and crevices of the rocks, where it lodges
until frozen; then it expands and acts like a wedge, widening cracks,
chiseling off edges, and even breaking rocks asunder. In regions where
frequent frosts occur, the destructive action of water works constant
changes in the appearance of the land; small cracks and crevices are
enlarged, massive rocks are pried up out of position, huge slabs are
split off, and particles large and small are forced from the parent
rock. The greater part of the debris and rubbish brought down from the
mountain slopes by the spring rains owes its origin to the fact that
water expands when it freezes.

[Illustration: FIG. 21.--The de