The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1872-08-03

any poiut WHOM ialIlug upon gOod
conductor. But such au arrangement
being obviously inadmissible, we must
so arrange matters that the most exposed
points shall be the conductor aud its
connections The French Academy
recommended the use of rods elevated
nine to twelve feet above the building,
and, after a good deal of experiment
aud observation, came to the conclusion
that rod was capable Of protecting
efficiently space covered by radius
equal to twice the hight Of the rod,
above the most elevated part of tAe
building For ourselves, very care.
ful examination, Of the conditions which
arise during a thunderstorm, leads us
to place no confidence whatever 10 Gle
waited rods, and to depend wholly upon
so arranging the conductor that every
part OF the building shall be protected
1t is obvious that the rod should be
carried from the roof to the ground by
the shortest possible way. Some have
even recommended that il be carried
down the chimney plan in which
there is nothing Objectionable, provided
it happen to be the most convenient
Auaeliag Lightning Rods to Bull
hgs.-lt is a prevalent opinion that
lightning rods should be carefully iu-
sulated from the buildings to which
thoy are attach d, aud hence most rods
are made to pass through glass tubes
or insulators, the avoEed object being
to prevent the electricity from passing
into the building. The extreme WORTH
lessness Of such arrangements ought to
be obvious to any person who ever OBJ
served fash Of lightning. The dis
charge from a powerful Rhumkorf coil
will pierce through five inches OF solid
glass, SO that, il a lightning rod we're
entirely cased in glass tube, an artif
cial fash of lightning can be produced
which will pass through it as easily as
a spark from one of the old machines
would pierce card And if such a
result can with safety be produced by
artificial means, in room filed with
people, what would be the limit to the
effects produced BY natural means
where thousands Of acres Of cloud sur
iace are engaged! InsuIators do very
well TO talk about, but as a security
against Heavens artillery they are pow
erless.
Lightning rods should be connected
with all large masses Of metal which
may exist in or upon the house, such
as metallic roofs, tin or iron cutters
or pipes, iron railings, etc. In the sec
ond place, the rod should be attached
to the house in the neatcst aud least
obtrusive method possible Ii the rod
be fat, it may be pierced with holes
a0d tackled directly TO the building
but better way, both for roun i, square
aud fat rods, is to employ properly
shaped staples Of stout wire. These
staples may be driven into the siudding
Of wooden houses or into the joint Of
brick walls, aud, when properly painted,
will not present an unsightly appearance.
Termination ia the Groud.-Upon
the perfection Of the ground termina.
ton mainly depends the value of the
lightning rod. If this be defective, no
other good features can possibly mako
up for it. Aud yet, so little is it un
derstooi, that a careful examination OF
a large number Of rods leads us to be.
lieve that fully one half the lightning
rods in existence are defective in this
respect, aud, consequently, furnish but
an insufficient protection.
Iron conducts better than water, but
water conducts better than dry earth.
And just us we are able, by iucreaing
its size, to make au iron rod conduct as
freely as copper one, so, by inereas
ing the yolumesof water or soil employ
ed to carry of electricity, We can make
it almost as eff cient as the metallic con
ductor. These facts lead us to the fol
lowing conclusions l. The end Of the
rod ought to be made to terminate 10 a
layer of soil that is permanently wet
aud 2. TIE end Of the rod ought to expose
to this soil as large a surface as possible
Permanently moist earth is to be at.
taiued only at considerable depths =
say at the level Of the water in the wells
in the vicinity. Unless we reach this
point, We can never be sure that our
rod does not terminate in dry or but
slightly moist soil; consequently nc
effort should be spared in sinking the
rod sufficient depth. This is most easily
accomplished at the time when the ioun,
dations are laid and we would advise
all builders to sink the lightuining rod
termination when they sink the foun-
dation. A short portion Of the stem
may be allowed to rise above the ground
aud the conductor may be arranged and
attached at a subsequent period.
1t is common practice among light
ning rod men To form the earth termi-
nation by simply driving a crowbul
into the earth, aud inserting the end
Of the rod in the hole thus formed. M
reliance can be placed on an earth con.
nection made ia this manner. Ths
crowbar may have been driven into
erfec,ly dry sand and, in any event
the amount of surface exposed by the
| rod, and the consequent section OF eartl
brought into action, is altogether too
small.
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1t is injurious for child to associat,