Experiments and Observations on Electricity Made at Philadelphia in AmericaFranklin, Benjamin
History
Experiments and Observations on Electricity Made at Philadelphia in America
Franklin, Benjamin
Electricity -- Early works to 1850
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 cieling, 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 destroy'd, 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, and 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 fire-fly 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, tho' at a considerable distance, 'tis
surprizing to see how suddenly it flies back to the tube. Points of wood
will do 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 shew that points will _throw off_ as well as _draw off_ the electrical
fire; lay a long sharp needle upon the shot, and you cannot electrise 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 electrised 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 beforementioned.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account