The Ohio Democrat. (Logan, O. [Ohio]) 1886-1906, 1886-07-31
{ LIGHTNING STROKES.
A Plausible Explanation of the Remarita
BILE Increase of Thundcr-Storms.

A Plausible Explanation of tho Rcmarisa-
BILE Increase of Thundcr-Storms.
The researches of Prof. Won Petzold.
Karstcn. Weber and others have proved
that the number of damaging strokes of
lightning has consider. bly, increased
during the last fifty years, and this in
crease can not be explained by the thco-
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 u 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 or
other strokes to the number of buildings
in u certain district. This ratio, called
by the German naturalists bhtzgetahr
danger from liGhtning), increased in
the kingdom of Bavaria from 1914 to
1882 three-fold (according to records of
insurance companies even five-fold),
and other countries show the same in
crease.
AS in nature each phenomenon must
have its 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
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 moro
made the projecting points of certain
area. and therefore attract the light
nlng; bcs des. this decrease effects II
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 us
gas and water works. wcather-cocks,
etc. But this theory does not explain
why, especially country houses. which
commonly lack these kind of construc-
tions, 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
prisng increase of strokes during so
short period. There must be more
general and fundamental cause.
Through what can the electrical in
tensity during thunderstorm be
so strongly increased that Il larger num-
ber of lightning strokes pass over to the
earth than was the case heretofore? 1t
is not so much the increasing number
of thunderstorms 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-
ber 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-
pherc 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
vepor 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 thundcr-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 clec-
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.
opment of electricity during thunder.
storms can not be otherwise explained
than by purely mechanical cause anal,
agous to the mechanical force of the hy-
o-clectrical machine. Now, as our at,
mosphere contains so much more dust
than in former years, the fact must be
of great influence regarding the inten-
sity of electrical phenomena during
thunder-stOrms; from the same reason
ing are explained volcanic eruptions
That this increased force of thunder'
storms must manifest itself in the great
or violence and more dangerous charac
ter of lightning strokes will be eviden
to the reader But there is another
cause to be mentioned 1t is an estab