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.

But how do we get the cars back? It is pleasant sliding down hill on a

rail, but who pulls the sled back? Gravitation. It is just as willing

to work both ways as one way.

Think of a great letter X a dozen miles long.

Lay it down on the side against three or four rough hills. Bend the X

till it will fit the curves and precipices of these hills. That is the

double track. Now when loaded cars have come down one bar of the X by

gravity, draw them up by a sharp incline to the upper end of the other

bar, and away they go by gravity to the other end. Draw them up one

more incline, and they are ready to take a new load and buzz down to

the bottom again.

I have been riding round the glorious mountain sides in a horseless,

steamless, electricityless carriage, and been delighted to find

hundreds of tons of coal shooting over my head at the crossings of the

X, and both cars were drawn in opposite directions by the same force of

gravity in the heart of the earth.

If you do not take off your hat and cheer for the superb force of

gravitation, the wind is very apt to take it off for you.

Among the Forces · 第 18 / 43 题