MORE GRAVITATION

At Hutchinson, Kan., there are great beds of solid rock salt four
hundred feet below the surface. Men want to get and use two thousand
barrels a day. How shall they get it to the top of the ground? They
might dig a great well--or, as the miners say, sink a shaft--pump out
the water, go down and blast out the salt, and laboriously haul it up
in defiance of gravitation. No; that is too hard. Better ask this
strong gravitation to bring it up.

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