The Prince George's enquirer and southern Maryland advertiser. (Upper Marlborough, Md.) 1882-1925, 1916-09-08
LIGHTNING A MENACE
ON THE FARM
tectine Life And Property
From Lightning.
MYRON CREESE,
Maryland State College of Agriculture.

Maryland State College of Agriculture.
There are number of types of light
ming, the most common forms being
the "forked stroke" band lightning.
heat lightning and sheet lightning.
The last two forms of lightning are so
remote from the place where they are
observed that they are perfectly harm
less. Both the forked and band light
ming are extremely dangerous forms.
The dangers from lightning may be
classified as: % Dangers to person;
ca Dangers to property. In almost
every case the danger to person is linn
tied to shock which may result in in
Jury or death. Danger to property in
cludes the injury or death to livestock
as result Of shock, or destruction Of
buildings, trees, etc., either shattered
or set on fire.
Wise Precautions.
Statistics show that many persons
have been injured by lightning in open
fields, especially on hills towards
which the storm was approaching.
The only safe thing to do under such
conditions is to find dry depression
in the ground and to lie down until
the storm has passed. 1t is dangerous
to take shelter in thunderstorm un-
der tree or small group of trees;
lightning striking the trees may be
diverted from the tree trunk through
the persons body to the ground or
falling limbs may injure him. If there
Is tree or small group of trees in an
open field, it is safer to take up
position near the trees but not under
them, because lightning is more liable
to strike tall trees, which act like
lightning rods, than the person. A
person should take refuge in a build
ing before the storm commences and
avoid crossing an open field while the
storm Is passing.
1t Is very dangerous to take shelter,
during a storm, under metal roof
which is not thoroughly connected to
the ground by wires or pipes. Any
building, such as a dwelling house or
barn, is not entirely safe shelter I'M
less it contains some well grounded
metal extending above the roof. In
unprotected buildings the most dan
gerous places to occupy during
storm are near chimneys, fireplaces,
and the walls.
Protection To Buildings.
Protection from lightning does not
consist in nrovonfirO fha hlIf1Hinp
from being struck; but ~ providing
an easy path for the discharge to the
ground. Lightning rods may be made
Of iron or copper; but, on account of
the rapid corrosion of iron exposed to
the weather, it is probably cheaper in
the end to use copper. Rods should
be placed from to IL feet apart
along the ridge of the roof and one rod
should be placed near each chimney.
Rods near chimneys should project
two or three feet above them and
other rods should project at least three
feet above the ridge. All rods should
be fastened to the roof with short
heavy screws, or bolts. Probably the
best form of metallic connection be-
tween the rods and the ground is a
loosely woven wire cable of small cop
per wires. The cfoSs-section of the
wires in the cable should be about
equal to that of solid wire three
eighths of an inch in diameter. The
copper cable should be in one con-
tinuous piece, from one ground con-
nection near a corner Of the building
to the roof and down the diagonally
opposite corner to another ground con-
nection The cable should be carried
from the first ground up the side Of
the building near corner, along the
cornice to the ridge, along the ridge.
down the opposite cornice and down
the corner to the second ground. The
cable should be fastened to the rods
on the roof with special metallic
clamps; and to the building with spe-
cial forms of clamping devices or
ordinary pipe straps, the clamps or
straps being secured with short, heavy
nails or screws. No sharp bends
should be made in the cable and it
should be protected from mechanical
injury by mailing strip of board or
molding over the cable from the
ground line to q height of about six
feet. All spouting and any pipes, such
as ventilators, projecting above the
roof should be connected metallically
to the cable. Do not use insulators
anywhere in connection with lightning
rods With an L-shaped building, 1t
is wise to connect third ground to
the system at the angle of the L.
Proper Grounding.
BY grounding is meant the best cleo
trica1ly conducting ground connection
to be found near the building which Is
to be protected. Probably the best
ground is continuous extensive
metallic pipe system buried in the
earth, such as water-pipe system.
The simple process of connecting the
cable to a pipe driven several feet into
the ground is not generally sufficient
grounding. If an extensive water-pipe
system is not available for grounding,
pit two to three feet in diameter
should be dug down to permanent
moist earth. The ground cone or
plate, to which the cable is secured,
should be buried in the pit and sur
rounded with coke or charcoal to
depth of from one to two feet. The pit
should then be filled in with earth to
the ground level. Soil saturated with
stable drainage makes an excellent
ground, but possesses the disadvan-