1749
HIS INVENTION OF THE LIGHTNING ROD
by Benjamin Franklin
Electronically Enhanced Text (c) Copyright 1996, World Library(R)
His Invention of the Lightning Rod
NOW if the fire of electricity and that of lightning be the
same, as I have endeavored to show at large in a former paper, this
paste-board tube and these scales may represent electrified clouds.
If a tube of only ten feet long will strike and discharge its fire
on the punch at two or three inches distance, an electrified cloud
of perhaps ten thousand acres may strike and discharge on the earth
at a proportionately greater distance. The horizontal motion of the
scales over the floor may represent the motion of the clouds over
the earth; and the erect iron punch, a hill or high building; and
then we see how electrified clouds passing over hills or high
buildings at too great a height to strike, may be attracted lower
till within their striking distance. And, lastly, if a needle fixed
on the punch with its point upright, or even on the floor below the
punch, will draw the fire from the scale silently at a much greater
than the striking distance, and so prevent its descending toward
the punch; or if in its course it would have come nigh enough to
strike, yet being first deprived of its fire it cannot, and the
punch is thereby secured from the stroke; I say, if these things
are so, may not the knowledge of this power of points be of use to
mankind, in preserving houses, churches, ships, etc., from the
stroke of lightning, by directing us to fix, on the highest parts
of those edifices, upright rods of iron made sharp as a needle, and
gilt to prevent rusting, and from the foot of those rods a wire
down the outside of the building into the ground, or down round one
of the shrouds of a ship, and down her side till it reaches the
water? Would not these pointed rods probably draw the electrical
fire silently out of a cloud before it came nigh enough to strike,
and thereby secure us from that most sudden and terrible mischief?
The End
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