Such being the case on the prairies and unbroken plains, the evaporation of two or three days’ sun leaves them in almost the condition of a desert. This was the case in our new States, Nebraska, Kansas, Colorado and Indian Territory, which, now so productive, were, as our early Geography describes them, before the soil was broken to hold the rain for a while, the Great American Desert. On a hot day the air in the valleys is still and suffocating. Climbing up from the valley to the hill or mountain tops, you find a cool and refreshing breeze; the moisture in the air is becoming condensed. Here is where the philosophy of lightning seems to work a prominent part. The cold currents of air and moisture, collecting, seem to come in contact with this subtle and wonderful agent, and the result is like fire to powder, a vivid flash and explosion. Stand on the plain on a sultry day and watch that little white crest of what we call a thunderhead. The farmer who has hay down will notice it with a little anxiety. The sailor will think of his sails, and the picnickers will think about going home. Soon a flash, and a dark base is forming. Soon the rumble of thunder is heard; the girls with their bonnets on begin to look worried. The captain on his yacht is giving orders to reef sails, and Farmer Jones and his boys are cocking and pitching hay for their lives. The little white-capped clouds of an hour ago have turned into a black and threatening massed park of artillery. Every discharge deepens and darkens the advancing column. Just as the vessel’s sails are dropped and snugly reefed, just as the farmer rushes his team, with load of hay or grain, into his barn, and the picnic is almost under cover, the big drops of rain begin to patter. Another flash and quick report; a scream from the girls, nearly as sharp, and they rush for shelter, and down comes a torrent of rain. A slight cessation, another flash, and, like shaking a tree of fruit, every electrical explosion seems to shake down a fresh reserve of rain drops. This is in keeping with the theory that after great battles the cannonading produces a copious rainfall. It is a method at times adopted by military garrisons when destitute of water, when the atmosphere is in a favorable condition for rain, to get out a battery of artillery and have a season of vigorous firing, and generally with successful results. And while all this grand and complete arrangement supplies vegetation with its bathing and drinking, as said before, it has nothing to do with the living and lasting supply of our springs, lakes and rivers. They are fed from a never failing and almost unchanging source--that is, by the immense supply taken in at the polar holes in a river over 4,000 miles wide at each end of the Earth’s axis.