CHAPTER VII.

THE RAIN POWER.

The letter-box—The first mail—The invitation—A storm 110 predicted—The water boils away—The prediction fulfilled—Sorry mishaps—Fretfulness—Selfishness—The rain not needless—Quantity not excessive—A few calculations—Wonderful results—Annual fall of rain—Rainy regions—Little and often better than much and seldom—Object of the tropical rains—How the water forms clouds—Evaporation—Effects of heat—Why vapor rises—Visible vapors—Office of the winds—Why the rain falls—Snow and hail—Snow crystals—The Sahara—South American deserts—Poetry—Bryant’s “Rain Dream,”