CHAPTER XII.--A DAY ON THE RIVER.

A river, creek, lake--in fact, any body of water--is a source of
perpetual delight to children. Frank, Donald, and Susie have had the
river and creek before them all their lives. Now, under Uncle Robert's
teaching, the river will mean very much more to them. They take their
first lessons in the work of streams in carving and shaping the earth's
surface. The pebbles on the beach and the large, rounded stones will
soon have stories of the distant past to tell them. The "Big Book" is
opened to them, and they read the stories directly from its pages.

CHAPTER XIII.--A RAINY DAY.

The children get closer to the question of moisture, its use, and
distribution. The rain gauge helps them to measure the rainfall. Then
comes the problem of where the water goes after it reaches the ground.
"How far down does some of it go?" "When and where does it come out of
the ground?"

Arithmetic is brought in in measuring the rainfall and its distribution.

CHAPTER XIV.--THE WALK AFTER THE RAIN.

The problems in Chapter XIII move toward their solution, and new
questions are opened. The gully tells of the wearing of the water, and
foretells a river valley. The spring helps in the question of
underground water. The flowing river quickens the imagination in the
direction of the great ocean.

CHAPTER XV.--THE BIG BOOK.