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.
This chapter should be read by parents to the children, as many sentences need expansion and explanation. Hints are given of great things which lie beyond the child's horizon. Discoveries that have changed mankind are referred to.
Children's permanent interests are the keynotes of instruction and the infallible guides of the teacher. To continue and sustain their spontaneous observation and desire for investigation leads directly to the study of the best books, and lays the basis for a thorough and profound study of God's universe.