from highwaymen, cranks and policemen. To defend
himself he uses heavy and dangerous guns, with which to destroy his
enemies. This is wrong. He has no right to take away what he can not
bestow; to destroy what he can not create. To kill a fellow-creature
is a horrid crime, even if done in self-defense. Therefore, my second
gift to you is this little tube. You may carry it within your pocket.
Whenever an enemy threatens you, be it man or beast, simply point the
tube and press this button in the handle. An electric current will
instantly be directed upon your foe, rendering him wholly unconscious
for the period of one hour. During that time you will have opportunity
to escape. As for your enemy, after regaining consciousness he will
suffer no inconvenience from the encounter beyond a slight headache."

"That's fine!" said Rob, as he took the tube. It was scarcely six
inches long, and hollow at one end.

"The busy lives of men," proceeded the Demon, "require them to move
about and travel in all directions. Yet to assist them there are only
such crude and awkward machines as electric trolleys, cable cars, steam
railways and automobiles. These crawl slowly over the uneven surface
of the earth and frequently get out of order. It has grieved me that
men have not yet discovered what even birds know: that the atmosphere
offers them swift and easy means of traveling from one part of the
earth's surface to another."

"Some people have tried to build airships," remarked Rob.

"So they have; great, unwieldy machines which offer so much resistance
to the air that they are quite useless. A big machine is not needed to
carry one through the air. There are forces in nature which may be
readily used for such purpose. Tell me, what holds you to the Earth,
and makes a stone fall to the ground?"

"Attraction of gravitation," said Rob, promptly.

"Exactly. That is one force I refer to," said the Demon. "The force
of repulsion, which is little known, but just as powerful, is another
that mankind may direct. Then there are the Polar electric forces,
attracting objects toward the north or south poles. You have guessed
something of this by the use of the compass, or electric needle.
Opposed to these is centrifugal electric force, drawing objects from
east to west, or in the opposite direction. This force is created by
the whirl of the earth upon its axis, and is easily utilized, although
your scientific men have as ye