The Fargo forum and daily republican., 1909-08-09
RIGHT kind OF
LIGHTNING RODS
STATE COMMISSIONER or lNsuR-
ANcE COOPER FURNISHES SOME
INTERESTING FACTS AsouT
LIGHTNING CONDUCTORS, AND
THEIR USE AND ABUSE.

THEIR USE AND ARusE.
AT this time OF the year when almost
daily reports are coming in from va
rious parts OF the state. telling Of ia
talities and serious damage caused by
lightning. information concerning light
ming conductors is particular timely.
The following is from the latest Sulle-
tin issued by State Commissioner OF
Insurance E. c. Cooper:
Inquiries frequently reach US at this
time OF the year as to what is the best
system of lightning rod protection for
buildings. For the bene1t of all who
may be interested we quote below an
article on Essentials of Lightning Rod
Construction by Hon. w. S. Rogers,
ex-state fire marshal Of Ohio.
In France the lightest galvanized
steel rod permitted is three-flfth OF an
inche square. A rod of copper must
weigh, according to the scientists of
Germany, as much as q solid copper
wire one-third of an inch in diameter.
The lghtest rod among the seventeen
endorsed by the lightning rod commit
tee OF the State Association of Farm
Mutual Insurance companies is a cop
per cable, weighing about 1s7 pounds
to the thousand feet.
"It must be run from permanently
noise earth up to and along the comb
of the building and down to perma-
nently moist earth.
-, h,ang5
must rise from the circuit, height of
FIVE feet every twenty feet along the
roof comb and there must be on ris-
ing above and close beside each Chin
ney, or other prominence.
"On each upright section must be
one or more tops of a metal that will
stay bright.
"The rod must be held away from
the building-not nailed to 1t.
''To disregard any OF these 'musts'
is to seriously impair the value Of the
rod. A rod that in any way fell short
of these requirements would not be
worth putting up.
The Best Shape.
The metal in a rod should be shaped
so as to give it large surface, be-
cause the current caused by a thunder
bolt is of the sort that travels near the
surface of the conductor That is call
ed skin effect for the electricity
crowds into the one -thirtfeth Of an inch
next to the external surface. Many
lightning rod agents believe and teach
that electricity travels on the outside
of a wire. 1t certainly cannot.
'.A steel rod is rolled in a star shape
and galvanized. Another rod is made
by rolling sheet copper over star-shap-
ed Steel This gives a copper surface
and a metal core to take UP heat into
which the energy OF the fash is con
verted. All other copper rods are
made of many wires in order that they
may have large surface. The way in
which the wires in copper cables are
twisted or woven does not effect their
capacity for taking care OF lightning
strokes.
"An ideal rod, so far as conduction
is concerned, would be one in tape form,
but II would be inconvenient and liable
to accident.
5uryina the End.
Cloud electricity forces its way
through the air to reach the under
ground water which feeds our wells.
A rod is worthless il not run down to
where there is permanent moisture. In
most localities this depth is eight to
ten feet. In rodding an expensive
building it is desirable, but not neces-
sary, to attach a mass of metal 10
the end of the rod.
"A section Of rod must rise well
above each chimney for the moisture
in smoke woakens the resistance of
the air to electricity. The kitchen chin
NV, above all others. should be pro-.
tected for IT is the ore most used in
the thunderstorm season.
There is no we'll established rule in
regard to connecting cutters, saddles,
rain spouts and oth.F metals in q
building to the rod by wires. When a
rod is struck there are oscillations
and surgings of electricity in it's neigh
borhood, so o spark may be given of
by any metal near by. If a rod runs
within few inches of metal that is
not grounded. the practice is to con-
meet them. Gas pipes should not be
connected to the rod.
The Points.
"The greater the number Of points
the greater the silent discharge from
the rod to avert stroke, and the
greater the gathering power of the rod
IL a stroke does come. Therefore to
use clusters of points is wise.
The fact that many OF the long
slender points are melted when struck
shows that they should be made thick
er at the expense Of lenght
"Glass insulators hold rod well
but electricity does not leave metal
to run on siding or shingles even when
they are rain-w
Before sawmills had removed all the
tall timber lightning struck trees rath-
er than houses. A tree trunk is a
bundle Of pipes full Of water, which is
one Of the best conductors, and all
trees that grow tall, have a tap-root
reaching to permanently moist ground
Because wood is not a good conductrk
a tree is often torn asunder by part OF
the energy Of the thunder bolt being
converted into heat, which changes the
water TO steam so suddenly that its