many would it take? We would need to distribute them over the whole
earth: from pole to pole, from side to side, over all the land and sea.
Then they would need to be so near together that a mouse could not run
around among them.

Here is a measureless power. Can it be gotten to take Pittsburgh coal
to New Orleans? Certainly; it was made to serve man. So the coal is
put on great flatboats, 36 x 176 feet, a thousand tons to a boat, and
gravitation takes the mighty burden down the long toboggan slide of the
Ohio and Mississippi Rivers to the journey's end. How easy!

[Illustration: The Head of the Toboggan Slide.]

One load sent down was 43,000 tons. The flatboats were lashed together
as one solid boat covering six and one half acres, more space than a
whole block of houses in a city, with one little steamboat to steer.
There is always plenty of power; just belt on for anything you want
done. This is only one thing that gravitation does for man on these
rivers. And there are many rivers. They serve the savage on his log
and the scientist in his palace steamer with equal readiness.




THE FAIRY WORKS A PUMP HANDLE

The Slave of the Ring could take Aladdin into a cave of wealth, and by
speaking the words, "Open Sesame," Ali Baba was admitted into the cave
that held the treasures of the forty thieves. But that is very little.
I have just come from a cave in Virginia City, Nev., from which men