The Louisiana Democrat. [volume] (Alexandria, La.) 1845-1918, 1886-08-04
LIGHTNING STROKES.


Detroit Free Press.
LIGHTNING STROKES.
A Plausible Explanation of the Remarka
BILE Increase of Thunder-Storms.
The researches of Prof Won Petzold,
Karsten, Weber and others have proved
that the number of damaging strokes OF
lightning has considerably increased
during the last fifty years, and this in.
crease can not be explained by the theo
ry that, owing to the growing number
of houses, factories, etc., the number Of
lightning strokes increased proportion.
ately; to the contrary, this number
ought to decrease, as every building
even when not protected by lightning.
rod, effects an equilibrium of the oppo-
site electric potentials, and therefore the
number of lightning strokes ought rela,
lively to decrease with the relative num-
Der of buildings. This, indeed, is
proved by the fact that in the space Of
one year among one hundred thousand
buildings there occurred but thirteen
cases of lightning stroke in cit.
les, against twenty-three strokes
on buildings in the country. We, there.
fore, have to take this natural phenom.
enon from another point of view, and
to consider the ratio of damaging OF
other strokes to the number of buildings
in certain district This ratio, called
by the German naturalists bhtzgetaM
danger from Legitimacy, increased in
the kingdom of Bavaria from 1874 to
1882 three-fold (according to records OF
insurance companies even five-fold,
| crease.
As in nature each phenomenon must
have it's cause, the question arises: To
what cause is due the aforementioned
facts? And this question not only is Of
scientific interest, but also Of great
7 practical Importance A great many
theories have already been advanced to
explain this phenomenon; among 9TH
ers that, owing to the decrease Of the
woodland, houses are more and more
made the projecting points of certain
area. and therefore attract the light
mig; besides, this decrease effects a
greater rise in temperature in summer,
and, in consequence, more nu-
merous thunder-storms. Others find
the cause of it in the large
increase of such constructions as
gas and water works, weather-c cocks,
etc: But this theory does not explain
why, especially country houses, which
commoaly lack these kind of construc.
tons, are mostly exposed to danger
from lightning. Admitting that these
causes may to some extent explain the
increase of danger from lightning, they
are not sufficient to fully show the sur
prising increase of strokes during 80
short a period. There must be more
general and fundamental cause.
Through what can the electrical in.
tensity during a thunderstorm be
so strongly increased thata larger mum.
Der of lightning strokes pass over to the
earth than was the case heretoforep II
is not so much the increasing number
of thunder-storms as their greater force
which produced the danger.
As the main cause we now point out
the enormous increase in the last fifty
years of factories, railroads, steamboats,
in short, of all constructions filling
the atmosphere with smoke, va
pors, particles of dust of every
description. When we consider that
every day thousands of locomotives,
thousands Of steamers go around
the earth; that thousands of factories OF
all kinds daily emit enormous quantities
of smoke, vapor and dust into the air;
that, especially in cities, the large num-
Der of houses produce immense guam.
titles of smoke and dust, the assertion
will not seem incredible that there is
certainly one hundred times the smoke,
dust and gases absorbed in the atmos-
phere that there was fifty years ago.
Already with the naked eye the impure
state of the atmosphere may be noticed.
Go through the coal districts of Man
chester, England, through those Of
Pennsylvania, through the city of Pitts
burgh, and you will notice a layer of
vapor constantly lowering over them;
the air is filled with foul gases, and
every object is more or less covered
with the settling particles of dust.
The conditions being established, We
have to consider their relations to the
violence of thunder-storms. To give
the reader better conception of this
relation we will briefly discuss the
theory of the thunderstorm and
the origin of electricity thereby
developed. Friction is now generally
accepted to be the cause of the
electricity in thunderstorm. Friction
between air and particles of ice (accord.
ing to Luvine) or between air and mole
cules of water (according to Andries) is
the main cause of that electricity. When
besides these factors particles of dust are
| filling the atmosphere the development
of electricity is highly increased. 1t is
the election of steam and ashes common
to the phenomenon which causes the
thunder-storms attending it to assume
an exceedingly violent character. That
the pyramid of Cheops is rendered cleo
trical by the whirling dust of the desert
may here also be mentioned. 1t is moth.
ing but the friction of the grains of sand
on the surface of the pyramid that causes
electricity to originate.
The author of this essay claims that
the rapid, enormous and lasting devel-