Evening star. [volume] (Washington, D.C.) 1854-1972, 1857-08-22
LIGHTNING RODS.

statistician, the late Francis Arago, did not
miscalculate the chances, a man is Just as La
bic, and no more, to be killed by lightning, as
by the falling Of flower pot from the window
OF house he may be passing. Still the same
dread which at the faintest muttering of thun-
der drove Tiberius from his revels and forced
him, crowned with laurels and clothed with
badger skins, to seek refuge in subterraneous
vault, exerts its sway more or less powerfully
In every breast The late fearful storms have
awakened a renewed and melancholy interest
In electricity, and the question is eagerly
asked, whether a recurrence of the sad events
OF the iasttwo weeks may be prevented whether
any adequate protection against the ravnges Of
lightning does indeed exist
Since the experiments of Franklin in June.
1852, iron or copper conductors have enjoyed at
best du biOus reputation Their theory ia nm
impeachable. In practice they have often been
found worse than useless. During the recent
storms, houses to which the I,test pattern of
rods had been affixed, were, in two instances at
least, struck and seriously damaged. Instances
are rather wanting to prove the virtue which
science has assigned to metallic conductors
Notwithstanding this, the faith of men of
science in the good qualities Of Frankln's in
vsntlon has not been shaken. The mischief
has been OccaSioned by faults Of construction
alone.
memorable instance of this is to be found
in case of the church at North Hampton in this
20 the steeple, but its termination was in n
granite rock, only short distance below the
surface of the earth. The lightning finding no
conducting substance at the bottom of the rod
reaseended, and passing into the church caused
much damage.
Much has been said in favor of insulation.
and brass pointed iron rods with glass ipsula-
tors, have for the last few years been zealously
hawked about the country. The principle so
eagerly cOntended for amounts to nothing An
inch or two Of glass can offer no resistance to
the force Of a thunderbolt, except perhaps for
an instant to impede its downward course. As
soon as vapOr or rain have moistensd its sur
face, II ceases TO be a non-cOnductOr, and insu-
lates the rod no more than an iron spike or
clamp, which last L. equally as safe fastening
The electric fluid viii not turn in its passage to
the ground for so feeble an attractive force
There are few conditions indispensable to
every ell-sdjusted conductor. First 1t must
be perfectly connected with the ground In
less it penetrates to 4 depth Of ten or twelve
feet, or to earth constantly moist, the electricity
will reascend, and perhaps pass through the
house. Dry ground Is nOn-conductor. A
well is the best termination for rod. Chsr-
coal thickly strown around the iron will add
much to II. conducting and diffusing power
Many, If not most, Of the conductors now in
use pas. only two or three feet below the sur
face, and are, consequently, not only useless
but dangerous. To this cause may be referred
q large portion of the injuries of houses re-
garded as perfectly secured
In the second place, the necessity OF q per-
feet connection of all parts If the rod is very
obvious. They should be screwed, not linked
together. Electricity passes more easily over q
smooth than an irregular surface Thirdly
The points are not merely ornamental append
ages. They draw tho electricity from the
clouds, while still at a distance prevent its
union with the electricity Of the earth, and
diffuse II in the atmosphere. If the point be-
comes blunted, this power is diminished or lost,
but the conductor will continue safely 10 con-
vey the electric current 10 the ground An
amusing story is told Of George III, strikinyly
characteristic Of his we'll known obstinacy and
inyeterate prejudice. Franklin advocated
pointed rods. The French Swans regarded
spheres as better dispensers Of electricity
wishing to be safe, and yet hating the repub-
icani,m Of Franklin, the bigated monarch had
sphere crowned conductors aft xed TO the Chin
neys Of bis palace.
One point will protect circle whose dame
ter is equal 10 the height of tho rod above the
chimney or roof to which il lie fastened The
practice OF connecting all the points with one
ground terminating conductor is fatally erro-
neous; there should be at least one conductor
for every two prominent points. Copper has
greater conducting power than iron, but 1t is
much more expensive.
That rod, when properly adjusted, 1. q pro-
lection against lightning, We do not doubt, but
II is equally certain that when imperfect il il
worse than nothing. knowledge and common
sense necessary in their construction as
elsewhere. Lightning-rods, as well as other
things, sometimes require examination, and
need repsir.--New Hampshire Statesman