lights. He found by experiments with this machine
that bodies thus exerted by friction may impart electricity to other
bodies, and that bodies so electrified may repel as well as attract.

Sir Isaac Newton made an electrical machine of glass, and Stephen Gray,
in 1720, said that if a large amount of electricity could be _stored_,
great results might be expected from it.

Charles Francois Dufay detected that there were two kinds of
electricity, which he called "vitreous" and "resinous."

A great discovery was coming. The first beams of a new planet were
rising. How did there come into existence the "magical bottle" known as
the Leyden jar?

At Leyden three philosophers were experimenting in electricity. "We can
produce electrical effects," said one. "If we could accumulate and
retain electricity we would have power."

They electrified a cannon suspended by silk cords. A few minutes after
ceasing to turn the handle of the electrical machine which supplied the
cannon with fluid, the charge was gone.

"If we could surround an electrified body with a nonconducting
substance," said Professor Musschenbroek, "we could imprison it; we
could accumulate and store it." He added: "Glass is a nonconductor of
electricity, and water is a good conductor. If I could charge with
electricity water in a bottle, I could possess it and control it like
other natural powers."

He attempted to do this. He suspended a wire from a charged cannon to
the water in a bottle, but for a time no result followed.

One day, however, Mr. Cuneus, one of the scientists, while engaged in
this experiment, chanced to touch the conductor with one hand and the
electrified bottle with the other. It was a mere accident. He leaped in
terror. What had happened? He had received an electric shock. What did
it mean? A revolution in the use of one of the greatest of the occult
forces of Nature.

Terror was followed by amazement. Mr. Cuneus told Professor
Musschenbroek what had happened.

The professor repeated the experiment, with the same result.

If electricity could be secured, accumulated, and discharged, what might
not follow as the results of further experiments?

It was several days before the professor recovered from the shock. "I
would not take a second shock," he said, "for the kingdom of France!"

Thus the Leyden jar came into use. The news of the experiment flew over
Germany and Europe. Scientific people everywhere went to making Leyden
jars a