g electrified before by
the other bullet; and thus the wheel increases its motion, till the
resistance of the air regulates it. It will go half an hour, and make,
one minute with another, twenty turns in a minute, which is six
hundred turns in the whole, the bullet of the upper surface giving in
each turn twelve sparks to the thimbles, which make seven thousand two
hundred sparks, and the bullet of the under surface receiving as many
from the thimble, these bullets moving in the time nearly two thousand
five hundred feet. The thimbles should be well fixed, and in so exact
a circle, that the bullets may pass within a very small distance of
each of them.

If instead of two bullets you put eight, four communicating with the
upper surface, and four with the under surface, placed alternately,
(which eight, at about six inches distance, complete the
circumference,) the force and swiftness will be greatly increased, the
wheel making fifty turns in a minute; but then it will not continue
moving so long.

_Resin ignited by Electricity._

Wrap some cotton wool, containing as much powdered resin as it will
hold, about one of the knobs of a discharging-rod. Then having charged
a Leyden jar, apply the naked knob of the rod to the external coating,
and the knob enveloped by the cotton to the ball of the wire. The act
of discharging the jar will set fire to the resin.

A piece of phosphorus or camphor wrapped in cotton wool, and used in
the same way, will be much more easily inflamed.

_Spirits ignited by Electricity._

Hang a small ball with a stem to the prime conductor, so that the ball
may project below the conductor. Then warm a little ardent spirit, by
holding it a short time over a candle in a metallic spoon; hold the
spoon about an inch below the ball, and set the machine in motion. A
spark will soon issue from the ball and set fire to the spirits.

This experiment may be varied different ways, and may be rendered very
agreeable to a company of spectators. A person, for instance, standing
upon an electric stool, and communicating with the prime conductor,
may hold the spoon with the spirits in his hand, and another person,
standing upon the floor, may set the spirits on fire, by bringing his
finger within a small distance of it. Instead of his finger he may
fire the spirits with a piece of ice, when the experiment will seem
much more surprising. If the spoon be held by the person standing upon
the floor, and the i