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Snap But In The Great Operations Of Nature The Light Is What We Call Lightning And The Sound Produced At The Same Time Though








generally arriving later at our ears than the light does in our eyes)
is, with its echoes, called thunder.

If the communication of this fluid be by a conductor, it may be
without either light or sound, the subtle fluid passing in the
substance of the conductor.

If the conductor be good, and of sufficient bigness, the fluid passes
through it without hurting it. If otherwise, it is damaged or
destroyed.

All metals, and water, are good conductors. Other bodies may become
conductors by having some quantity of water in them, as wood and other
materials used in building, but not having much water in them, are not
good conductors, and therefore are often damaged in the operation.

Glass, wax, silk, wool, hair, feathers, and even wood perfectly dry,
are non-conductors: that is, they resist instead of facilitating the
passage of this subtle fluid.

When this fluid has an opportunity of passing through two conductors,
one good and sufficient, as of metal, the other not so good, it passes
in the best, and will follow in any direction.

The distance at which a body charged with this fluid will discharge
itself suddenly, striking through the air into another body that is
not charged, or not so highly charged, is different according to the
quantity of the fluid, the dimensions and form of the bodies
themselves, and the state of the air between them. This distance,
whatever it happens to be between any two bodies, is called their
striking distance, as, till they come within that distance of each
other, no stroke will be made.

The clouds have often more of this fluid in proportion than the earth:
in which case, as soon as they come near enough, (that is, within the
striking distance,) or meet with a conductor, the fluid quits them and
strikes into the earth. A cloud fully charged with this fluid, if so
high as to be beyond the striking distance from the earth, passes
quietly without making noise or giving light, unless it meet with
other clouds that have less.

Tall trees and lofty buildings, as the towers and spires of churches,
become sometimes conductors between the clouds and the earth; but, not
being good ones, that is, not conveying the fluid freely, they are
often damaged.

Buildings that have their roofs covered with lead, or other metal, and
spouts of metal continued from the roof into the ground to carry off
the water, are never hurt by lightning, as, whenever it falls on such
a building, it passes in the metals and not in the walls.

When other buildings happen to be within the striking distance from
such clouds, the fluid passes in the walls, whether of wood, brick, or
stone, quitting the wall only when it can find better conductors near
them, as metal rods, bolts, and hinges of windows or doors, gilding on
wainscot, or frames of pictures, the silvering on the backs of
looking-glasses, the wires for bells, and the bodies of animals, so
containing watery fluids. And in passing through the house it follows
the direction of these conductors, taking as many in its way as can
assist in its passage, whether in a straight or crooked line, leaping
from one to the other, if not far distant from each other, only
rending the wall in the spaces where these partial good conductors are
too distant from each other.

An iron rod being placed on the outside of a building, from the
highest part continued down into the moist earth, in any direction,
straight or crooked, following the form of the roof or other parts of
the building, will receive the lightning at its upper end, attracting
it so as to prevent its striking any other part; and, affording it a
good conveyance into the earth, will prevent its damaging any part of
the building.

A small quantity of metal is found able to conduct a quantity of this
fluid. A wire no higher than a goose-quill has been known to conduct
(with safety to the building, as far as the wire was continued) a
quantity of lightning that did prodigious damage both above and below
it; and probably larger rods are not necessary, though it is common in
America to make them of half an inch, some three-quarters, or an inch,
diameter.

The rod may be fastened to the wall, chimney, &c., with staples of
iron. The lightning will not leave the rod (a good conductor) to pass
into the wall (a bad conductor) through those staples. It would
rather, if any were in the wall, pass out of it into the rod, to get
more readily by that conductor into the earth.

If the building be very large and extensive, two or more rods may be
placed in different parts, for greater security.

Small ragged parts of clouds, suspended in the air between the great
body of clouds and the earth, (like leaf gold in electrical
experiments,) often serve as partial conductors for the lightning,
which proceeds from one of them to another, and by their help comes
within the striking distance to the earth or a building. It therefore
strikes, through those conductors, a building that would otherwise be
out of the striking distance.

Long sharp points communicating with the earth, and presented to such
parts of clouds, drawing silently from them the fluid they are charged
with, they are then attracted to the cloud, and may leave the distance
so great as to be beyond the reach of striking.

It is therefore that we elevate the upper end of the rod, six or eight
feet above the highest part of the building, tapering it gradually to
a fine sharp point, which is gilt, to prevent its rusting.

Thus the pointed rod either presents a stroke from the cloud, or if a
stroke be made, conducts it to the earth, with safety to the building.

The lower end of the rod should enter the earth so deep as to come at
the moist part, perhaps two or three feet; and if bent when under the
surface, so as to go in a horizontal line six or eight feet from the
wall, and then bent again downwards three or four feet, it will
prevent damage to any of the stones of the foundation.

A person apprehensive of danger from lightning, happening during the
time of thunder to be in a house not so secured, will do well to avoid
sitting near the chimney, near a looking-glass, or any gilt pictures
or wainscot; the safest place is in the middle of the room, (so it be
not under a metal lustre suspended by a chain,) sitting in one chair
and laying the feet up in another. It is still safer to bring two or
three mattresses or beds into the middle of the room, and, folding
them up double, place the chair upon them; for they, not being so good
conductors as the walls, the lightning will not choose an interrupted
course through the air of the room and the bedding, when it can go
through a continued better conductor, the wall. But where it can be
had, a hammock or swinging-bed, suspended by silk cords equally
distant from the walls on every side, and from the ceiling and floor
above and below, affords the safest situation a person can have in any
room whatever; and what, indeed, may be deemed quite free from danger
of any stroke by lightning.





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