Because the air over the land at night is less heated than the air over the water; hence, the land-breeze feels cool. How rapidly does the wind move? A gentle breeze goes four or five miles in an hour; a high wind goes from twenty to fifty miles in an hour, and a hurricane goes from sixty to one hundred miles in an hour. Of what use is the wind? The wind carries away the impure air and injurious gases from cities and other places, so that they are the more healthy; it dries up the water on the surface of the earth, and thus promotes vegetation; it sweeps the clouds filled with moisture from the lakes and the oceans, over every part of the world, so that the water in them may fall in refreshing showers, to fill the springs, to purify the air, and in many other ways to make the earth a fitting place of abode for man. But these are only a few of the many blessings that an all-wise Creator has given us; and, for them all, we should ever remember to offer up to Him the homage of a grateful heart. [Illustration: Paddlewheel steamboat.] [Illustration: Decoration.] CHAPTER V. Water. [Illustration: Illustrated Capital W] Where do we find water? We find _water_ almost everywhere; above the earth, on the earth, and beneath the earth’s surface. Where do we find water above the earth? We find it in the air, in the form of vapor. Where do we find water on the earth? We find it in springs, in streams of water, and in lakes and oceans. Where else is water on the earth? It is in the sap of plants, the juice of fruits, and the blood of animals. Where do we find water beneath the earth’s surface? We find it in streams running in every direction. Has water any influence on climate? Yes; water causes many changes in climate. What changes does water produce in climate? It makes spring and summer cooler, and autumn and winter warmer. How does water make the Spring of the year cooler? The ice and snow while melting, take up a large amount of heat, which passes into the water as latent heat. Where does the melting ice and snow obtain this heat? They obtain it from the air, and from objects near the surface of the earth. What advantage is derived from this? The tender buds and blossoms are kept back in the spring until the ice and the snow are melted, and the earth becomes warmed, so that they are seldom injured by the cold. How does water make Summer cooler? By the streams, lakes, and oceans, which absorb heat from the sun; and, as the water is a poor radiator, but little of this heat is given off to the air. What effect does this heat produce upon the water? The temperature of the water is gradually increased by it during the hot weather of summer. How is this useful?