Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1895-07-03
PROTECTION FROM LIGHTNING.
The Utility of safety Rods-some In
tcrestiug Statistics.

The subject of atmospheric electricity
Is receiving much consideration from SCI
entists Just at present. Meteorologists
have been mainly content with collecting
statistics regarding the frequency and Sc
verify OF thunder-storms. Our Weather
Bureau. however. carrying out in this di-
rection it's policy OF making It's work OF
practical use to the people, has been
making a careful study of methods OF
protection from lightning In the Bulle-
tin No IL there has been given t5y Dir.
Alexander McAdie) n good deal OF ln'or-
mati1n on the subject. which VIII IN
douhiedly tend TO reduce the amount or
humbugging which has been going on IN
regard to lightning-rods.
Lodge, one of the highest authorities,
has said that any conductor lightning
rob IL better than none. although but few
or none of them are absolute and corn
plete safeguards. Some form Of lightning
rod Is essential To anything Ike security.
Putting aside the question Of the conn
narrative cheapness OF insurance against
lightning. AMI the cost Of lightning rods,
We can so at once TO the matter as 10
how much lightning-rods protect. In
order to Go this It is necessary to get an
idea Of the nature Of the action OF light
ming.
There exist all grades Of lightning dis
charges. from the STEADY strain" CT
gentle low. of the electric current, COM
parable to the flow OF water in river
with slow current, 20 the 'impulsiye
rush" or intense descriptive electrical die
charges of high momentum. which are
comparable 70 an avalanche on steep
mountain side. o. great flood. Where
the discharge is Of the former character
lightning-rod do protect. but In the latter
case even the best constructed conduct
ors lose their efficiency. just as safety
gate in waterway would prove useless
In the rush Of waters OF great Hood
IL was such a descriptive discharge Of
lightning which caused the damage 10 the
Washington monument on June >, 1879.
There are many flashes that are OF an
intensity which the human body can
readily withstand
Lightning-r0ds should be either OF cop
per tape. weighing six ounces 10 the foot,
or Of iron rod or tal3, weighing thistv-
five ounces to the foot. The top OF the
rod should consist OF clusters Of points
which have been plated TO prevent cor
rosion or rust. The grounding Of the
rod should be in damp earth or running
water. and independent grounds are pre-
cradle 10 water or gas-main pipes.
There Is no definite area OF protection de-
pending on the height OF the rod. The
risk OF a lightning stroke is about five
times greater in the country than In
the city. In fact, IL is hardly necessary
TO place rods on the ordinary block dwell
ing houses OF the city.
The region of greatest frequency of thun-
der-storms in the United States is in the
southeastern portion. extending from
Georgia to Mississippi where forty storms
occur each year at the average. In the
northern part of the United States not
more than twenty occur; and on the New
England coast but ten. The summertime
is the time OF greatest frequency; this
occurs in May or June TO the west AM
southwest of the Great Lakes. but the
time is retarded 10 July and August,
with progress toward the west, south.
and east Of this region. The general di-
rection OF approach In the United States
f. from the west; but In Sol Florida
they approach from the east. thus fol-
lowing the direction Of the general move
ment Of the atmosphere.
About two hundred and sixty people are
killed annually by lightning in the United
States. OF these casualties. usually 1
death occurs I'm each of January, Febru-
airy, November. and December; in
March. 3; April, 10; May. %; June. n;
July, 90; August. Is. September. 10; Octo-
Der. 70. The annual loss by ire due To-
lightning strokes is estimated at $500 -
90. OF the annual number OF SO build
ings set on fire. go were barns. stables.
aad granaries, a churches, and lSl dwell
ings