Stories of Invention, Told by Inventors and their FriendsHale, Edward Everett
History
Stories of Invention, Told by Inventors and their Friends
Hale, Edward Everett
Inventions; Inventors; Technology -- Juvenile literature
"For example, place an iron shot, of three or four inches diameter, on
the mouth of a clean, dry glass bottle. By a fine silken thread from the
ceiling, right over the mouth of the bottle, suspend a small cork ball
about the bigness of a marble; the thread of such a length, as that the
cork ball may rest against the side of the shot. Electrify the shot, and
the ball will be repelled to the distance of four or five inches, more
or less, according to the quantity of electricity. When in this state,
if you present to the shot the point of a long, slender, sharp bodkin,
at six or eight inches distance, the repellency is instantly destroyed,
and the cork flies to the shot. A blunt body must be brought within an
inch and draw a spark, to produce the same effect. To prove that the
electrical fire is _drawn off_ by the point, if you take the blade of
the bodkin out of the wooden handle, and fix it in a stick of
sealing-wax, and then present it at the distance aforesaid, or if you
bring it very near, no such effect follows; but sliding one finger along
the wax till you touch the blade, the ball flies to the shot
immediately. If you present the point in the dark, you will see,
sometimes at a foot distance and more, a light gather upon it, like that
of a firefly or glow-worm; the less sharp the point, the nearer you must
bring it to observe the light; and at whatever distance you see the
light, you may draw off the electrical fire, and destroy the repellency.
If a cork ball so suspended be repelled by the tube, and a point be
presented quick to it, though at a considerable distance, it is
surprising to see how suddenly it flies back to the tube. Points of wood
will do near as well as those of iron, provided the wood is not dry; for
perfectly dry wood will no more conduct electricity than sealing-wax.
"To show that points will _throw off_ as well as _draw off_ the
electrical fire, lay a long, sharp needle upon the shot, and you cannot
electrize the shot so as to make it repel the cork ball. Or fix a needle
to the end of a suspended gun-barrel or iron rod, so as to point beyond
it like a little bayonet; and while it remains there, the gun-barrel or
rod cannot, by applying the tube to the other end, be electrized so as
to give a spark, the fire continually running out silently at the point.
In the dark you may see it make the same appearance as it does in the
case before mentioned."
The next summer, that of 1748, the experiments went so far, that in a
letter of Franklin's to Collinson he proposed the electrical
dinner-party, which was such a delight to Harry and Lucy:--
Public-domain text, read in full here on John Shaqi.
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