New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1876-07-18

against the explanation. It is not clear why
the transfer of moisture to the sky should
make any change in electrical condition, unless
so said the scientific authOrities-there was a
chemical as we'll as mechanical change. In
fact while immense progress has been made
both in theory and in practical application as
to electricity, our knowledge concerning the
lightning of the sky is comparatively little ad-
vanced since the day when Eripuit cGlo tat-
men, sceptrumque tyraRAiS was written OF Ben
jamin Franklin.
.Another unusual freak of recent lightning is
tbe number of strokes in large cities. AS a
lule, trees and buildings that stand alone,
especially on high ground or in open country,
are most exposed to this danger: where there
are many houses or many trees toSether' the
thunderbot is less likely to fall. Cities enjoy
greater immunity also because they are plentl-
fully supplied with good electrical conductors,
such as metal roofs and the leaders from
them; the network of rails upon the streets
and of pipes beneath them; and, we may add,
though it is no excuse for keeping them there'
the telegraph posts and wires that dlshgure our
thoroughfares. All such things draw electricity
from lowering clouds, but draw 1t silently, ana
it passes without shock. This Is alse
the business of a good lightning-rod.
popular misrepresentation exists on this point.
Most people imagine tfat a .lightning-rod is to
attract and carry down lightning, as such. a
rod may have to do this once in great while
but in nineteen cases out Of twenty lt Ought
to be employed during thunder shower In
removing surplus electricity from the Clouds
40 that there will be no lightning stroke.
Want of correct ideas about this has caused
many persons to object to lightniug-rods alto
cetLcr for fear that the rod would draw light
ming.
we published at the time Of their ISSUE
few years ago, in The TRIBUNE, summary
of the statistics furnished by a German insur-
ance company that makes specially OF risks
from lightning They showed very conclu-
siycly that the risk to buildings was least
where the protection by lightning rods was
greatest, and vice versa. A similar result was
reached in England III the protection of tee-
graph poles by lightning rods. The efficacy
of the rod depends, however, upon certain well
known conditions, such as hat its parts are
we'll Tapped and welded its points are bright;
IFS thickness is sufficient for the roOf-space II
mass of moist earth, or metal. Some OF these
matters are apt to be neglected by unscrupu-
lous vendors OF "patent' rods. Ours Is not,
however the only country where frauds IN
lightning rods are executed. Quite recently
one of the most celebrated observatorles III
Italy was struck by lightning, the chief dam
aye accrung to the rod. Its platinum points
were melted. Now platinum does not melt
readily, even in the feryid heat of the electric
arc. So an examination was ordered and it
was found that the platinum points had con-
tained large percentage of lead.
But to return to our own recent thunder
showers They each provided from three or
four To half a dozen or more lightning strokes
in several cities. Few of these did serious
damage, though occasioning great alarm, as IN
the case of the Insane Asylum on Blackwells
Island and the building near the Reservoir at
Albany where the policemen were assembled.
Primarily we may account for the number of
strokes in cities ms well rs elsewhere by the
extraordinarily heavy charge of electricity that
was present during the shower, az displayed
in the rapidity, number and continuance of
binding flashes. But there was probably
secondary cause in the unusual number of
tail hagstal5 that had been erected Oh The
roofs of city buildings. Flagstaiis, especially
when wet, make fair conductors, as far rs
they 20: they stop just short enough
to be likely to bring lightning to
a point where it can do the most
damage. BY a good fortune which was
scarcely merited, il appears that in the ma
iority of these instances the greater part of the
destructive force was expended on the flag
stails. They were not rivcn or blown to
shrcds as trees sometimes are when all the
sap within is turned INTO steam 10y lightning
stroke; but what was left of them was SO
wrenchcd and broken that they will never
serve for another Fourth Of July.