Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1845-09-06
LIGHTNING RODS.


New Haven were lately struck by lightning have
excited much curiosity, and have led some persons
TO doubt the efficiency of lightning rods, seeing tina
in these instances they did not afford the requisite
protection. AS was to be expected, the subject has
already received the attention of Professors OLM
sTED and SLLMAN. The former gentleman in an
article which we find in the New Haven Palladium
says:
"ln regard to the dwelling house of Mr.. Stiman which
building OF moderate dimensions having each of its two
cimneys furnished with conductor and therefore, to appear
ance, uncommony well fortified cannot doubt that the
OF failure that already assigned by my respected colleague
Professor Siman-namely the fact that the rods descended
INTO the ground b c0 three inches, tminatEng tciM
blunt erfreity dry sand All the efficacy of conduc-
tor depends upon Its furnishing passage for the lightning to
the earth Were it terminate at the bottom in glass hot
tie the lightning would not touch it. It acts, not by attract
ing the electric fluid after the OF magnet but by
Quoting TO the earth and when the conducting medium is
interrupted by the nterpoon of non-conducto rod Of
iron loses all its power flash Of lightning.
Now, dry sand is almost quite bad conductor OF
electricity glass; and, in the present case the rod al
most ecctuay prevented from exertng proper Office
would have been had entered glass bottle Some have
that the shower which preceded the stroke must have
so Tar moencd the earth to render It conductor to the
depth of several inches II must however, be recoeced that
previous to the shower the ground quite dry that but
little rain had fallen previous the stroke that when the
face OF the earth is in dry, puveruent state rain but
slowly absobed and finally that the and grass that lie
the surface of the ground render its conducting
much inferior to those of the dense earth at the depth of per-
moisture. Hence, all writers the subject Of light
ming rods upon this poinha the rods must descend
to the depth OF permanent moistueas of cardinal i'm
portance In dry SOIL this depth is not less than from
to ten feet and majority OF the cases OF the failures
that have fallen under my observation have arisen from de-
feet in this particular although have before with
egregious instance of this point the pre-
sent would respectfully suggest that citizens examine
their conductors and how far they penetrate the EARTH be-
fore they conde to them the safety Of their families from the
attacks Of this terrible element At the tme il may be
well examine whether their rods continuous through
since Breaks like the hook andcye joints greatly impair
their efficacy and finally to that the rod ascends above
the ridge of the house to height equal in every direction,
to half the distance that it is required to protect Thus,
rod ascending feet above the RIDGE will protect space all
around it Of twenty feet and cannot be relied to do more
than this.
"The safety of Mr.. and Mrs. Stlman, who lodging
the angle of the house which violently assa
ed ascbe the fact that the bedsead Of hard and dry
maple well varshed and thus rendered SO good noncon
ductor nsulae them, cut off their communication
with the earth. Had the bedstead been of soft pine and
vanished not improbable that intense electric charge
would have sent off branch through their persons Its
the earth, unless the floor itself bad conductor
TO prevent it. Still had the bedsead been of iron, and in
free communication with the earth they would probably have
sustained injury since in that case the fluid would have
followed the metal rather than the human system, being
better conductor.
The second case the Iancaseran Schoohou
scarcely rendered clear readers without the
panying diagram. In this instance, although lightning rods
attached to the northern and southern chimneys of the
budng the ridge of the house, equdistant between the rods
was struck. DIR. OLnsTEp thus replies the question,
I" Why did not the lightning strike The other Of The
rods, rather Than point in the ridge half way bet,ceen
them 2"
" In the first place, the rods badly terminated at the
lower extremity, ending at the depth of two feet four
ches and the other of only inches, the earth being
dry state In the second place. the distance from the
OF the rod to the point Of attack greater than the
rule requires The rods about feet above the level
of the ridge, while the distance from the summit Of each rod
TO the point assaed least twenyv feet In the third
place, several nails and the point contributed TO de-
termne the charge in that direction while the power Of the
rods was too feeble to antagonist force of sufficient
intensity to divert the charge from direct Had the
charge either of the rods did to the point
A. would probably have taken that route but Preferred
the medium Of least resistance first enter the RIDGE then
divide into two branches to follow the nails along the raers
each to the iron braces thence to the rods and finally
the earth
son the WHOLE although there nothing in these
aordnay which ought diminish public confidence in
the safety of lightning rods when constructed according the
rules of science yet there enough not to trust to
badly constructed rods, and not employ incompetent artists
IN putting up new ones"
PROFESSOR HARE, of Philadelphia, has also been
attending to the subject in relation TO another case
of damage by lightning. This letter, which ap-
peared in the Philadelphia Inquirer, is in corrobora
ton of the opinions of Professors OLMsTED and
SmLMAN with respect TO the efficacy OF lightning
rods, if properly constructed We give the follow
ing extracts from this letter, feeling that the public
cannot possess too much information to the best
means of avertng so awful calamity:
In the Inquirer and National Gazette of the 18th instant
is mentioned that the barn of Mr.. Dewer Reading
struck by lightning while furnished with lightning rod
the end Of the building Although but i'll spare
the time from other objects in which engaged am led
call attention the sad consequences of this of not
putting up conductor intended for the protection of any
building against lightning the westernmost part and pre-
feraby the northwesernmost end am under the
impression that all hundergu in this part of the world
from the westward, and generally from the northwest
ward. We have sometimes from the southeast
companed BY dse electrical flashes but such genuine thun
degu produce dangerous discharges Of concentrated
lightning agreeaby my observations always above
stated Being consulted about days by the propre
tor Of house respecting the proper mode Of putting up
lightning rod advised that it should be secured the north
western chimney, while duly pointed extend about
ten feet above it. Had Mr. Dewler put up rod Ue point
edab0re and property terminated beoD the northwestern
most part Of his barn, am Of opinion that would not have
been struck. advance this opinion condionaly, because
lightning rod competent conductor Of electricity only
far terminates in contact with conducting medium
capable Of dusRg into the earth any electricity which may
be presented to it, Unfortunately the conducting OF
the son which these rods usually terminate due only the
moisture which naturally holds WHILE according to Caven-
dish the conducting power of itself is two hundred
thousand times less than that Of IRON II follows that an iron
rod when terminating in dry earth, wholly incapacitated
from acting conductor IL is like pipe plugged at the
lower end Even when the soil is moist the rod cannot
ceive electricity than the soil carry of from it
Hence under ordinary circumstances the competency of
ia the |