Thus the South Seas should supply mainly the water for the engine just described, while the northern hemisphere condenses it; we should, therefore, have more rain in the northern hemisphere. The rivers tell us that we have, at least on the land; for the great water-courses of the globe, and half the fresh water in the world, are found on the north side of the equator. This fact is strongly corroborative of this hypothesis. To evaporate water enough annually from the ocean to cover the earth, on the average, five feet deep with rain; to transport it from one zone to another; and to precipitate it in the right places at suitable times and in the proportions due,--is one of the offices of the grand atmospherical machine. This water is evaporated principally from the torrid zone. Supposing it all to come thence, we shall have encircling the earth a belt of ocean 3000 miles in breadth, from which this atmosphere evaporates a layer of water annually sixteen feet in depth. And to hoist up as high as the clouds, and lower down again, all the water, in a lake sixteen feet deep and 3000 miles broad and 24,000 long, is the yearly business of this invisible machinery. What a powerful engine is the atmosphere! and how nicely adjusted must be all the cogs and wheels and springs and _compensations_ of this exquisite piece of machinery, that it never wears out nor breaks down, nor fails to do its work at the right time and in the right way!--_Maury._ THE PHILOSOPHY OF RAIN. To understand the philosophy of this beautiful and often sublime phenomenon, a few facts derived from observation and a long train of experiments must be remembered. 1. Were the atmosphere every where at all times at a uniform temperature, we should never have rain, or hail, or snow. The water absorbed by it in evaporation from the sea and the earth’s surface would descend in an imperceptible vapour, or cease to be absorbed by the air when it was once fully saturated. 2. The absorbing power of the atmosphere, and consequently its capability to retain humidity, is proportionally greater in warm than in cold air. 3. The air near the surface of the earth is warmer than it is in the region of the clouds. The higher we ascend from the earth, the colder do we find the atmosphere. Hence the perpetual snow on very high mountains in the hottest climate. Now when, from continued evaporation, the air is highly saturated with vapour, though it be invisible and the sky cloudless, if its temperature is suddenly reduced by cold currents descending from above or rushing from a higher to a lower latitude, its capacity to retain moisture is diminished, clouds are formed, and the result is rain. Air condenses as it cools, and, like a sponge filled with water and compressed, pours out the water which its diminished capacity cannot hold. What but Omniscience could have devised such an admirable arrangement for watering the earth? INORDINATE RAINY CLIMATE.