But does it work down and up? Did any one ever know of gravitation raising anything? O yes, many things. A balloon may weigh as much as a ton, but when inflated it weighs less than so much air; so the heavier air flows down under and shoulders it up. When a heavy weight and a light one are hung over a pulley, the light one goes up because gravity acts more on the other. Water poured down a long tube will rise if the tube is bent up into a shorter arm. Exactly. So we bore a four-inch hole down to the salt and put in an iron tube. We do not care about the water. It is no bother. Then inside of this tube we put a two-inch tube that is a few feet higher. Now pour water down the small longer tube. It saturates itself with salt, and comes flowing over the top of the shorter tube as easily as water runs down hill. Multiply the wells, dry out the water, and you have your two thousand barrels of salt lifted every day--just as easy as thinking! We want a steady, unswerving force that will pull our clock hands with an exact motion day and night, year in and year out. We hang up a string, and ask gravitation to take hold and pull. We put on some lead or brass for a handle, to take hold of. It takes hold and pulls, unweariedly, unvaryingly, and ceaselessly. It turns single water-wheels with a power of more than twelve hundred horses. It holds down houses, so that they are not blown away. It was made to serve man, and it works without a grumble. Thus the higher force in nature always prevails over the lower, and the greater amount over the less amount of the same force. What is the highest force? THE FAIRY PULLS GREAT LOADS Far back in the hills west of Mauch Chunk, Pa., lie great beds of coal. They were made under the sea long ages ago, raised up, roofed over by the Allegheny Mountains, and kept waiting as great reservoirs of power for the use of man. But how can these mountains be gotten to the distant cities by the sea? Faith in what power can say to these mountains, "Be thou removed far hence, and cast into the sea?" It is easy. Along the winding sides of the mountains have been laid two rails like steel ribbons for a dozen miles, from the coal beds to water and railroad transportation. Put a half dozen loaded cars on the track, and with one man at the brake, lest gravitation should prove too willing a helper, away they go, through the springtime freshness or the autumn glory, spinning and singing down to the point of universal distribution. [Illustration: Incline at Mauch Chunk.] On one occasion the brake for some reason would not work. The cars just flew like an arrow. The man's hair stood up from fright and the wind. Coming to a curve the cars kept straight on, ran down a bank, dashed right into the end of a house and spilled their whole load in the cellar. Probably no man ever laid in a winter's supply of coal so quickly or so undesirably.