Evening star., 1896-07-18

ness of lightning strokes by distributing the
electricity evenly over the area covered.
A well-known electrician recently said that
on this account seat in q trolley car Is one
Of the safest places to which a person can
resort during an electric storm. The con-
tinuous underground piping and tin roofing
of city houses likewise aid in the distribu-
tion OF the lightning.
Recent meteorological and astronomical
observations have given rise to an interest
ing theory accounting for the source Of elec-
trio phenomena displayed in storms, as well
as for the latent atmospheric and terrestrial
currents always present. even in winter.
This theory Ii that such commotions as
lightning are only possible when the sun
spots are in a particular locality over the
surface of the SUM- and when the earth oc-
cupies a certain position In relation to them
Il is further believed that the masses of
matter thrown of by the sun when the lat
ter Is violently agitated at certain times
constitute the medium through which elec-
trfcal energy Is conducted from the sun to
tne earth. This same cause has been at
tributed to the aurora borealis, thought by
some authorities to be q form Of lightning
Power of Lightning Flashes.
Scientists in different parts of the world
are at work devising means of determining
the horse-powers. lengths, diameters and
duratlons OF lightning flashes. The most
accurate computation Of the power of an
exceptionally severe flash is said to have
lately been made in Germany. The bolt en-
tered house and struck a wooden post
melting two nails, each a sixth of an inch in
diameter. 1t was carefully estimated that
in order to melt nails of this volume and
material, and accomplishing the destruction
IN one-tenth OF second would require a
thunderbolt acting with a power equal to
that of $1,000 horses each lifting one nounS
15.OOo feet In one minute. A bolt of this
power, coming upon you, either above or
conductors.
Your Aunt Mary Jane will tell Won not
to hold pair of scissors or q needle and
not to wear steel Ittons or buckles on
your ciotnes during thunder storm, lest
these little things coax the thunderboJt
from sts regular path. Similarly ridiculous
is the old-fashicned notion that q single
pane of glass would refract the course of
bolt coming head on. AS to the diameter
OF FASH some severe ones have heen
found to measure a foot in this particu-
lar. A cross section Of a thunderbolt looks
IKE that OF a round iron bar heated to
Whteness The particles of the atmosphere
N realty become white hot on coming in
contact with the lightning. The flashes
which we commonly see during thunder
storms are found to be anywhere from 200
feeet to a half mile in length.
;, very recent studies of the duration of the
lightning flash have disclosed fact of
great interest to every one. This is that
"hat appears to us to be a sudden repeti-
ton, sometimes several times Of a light
nins nash Is In reality an hallucination
You nave invariably noticed that g. light
ming flash seems to appear in sudden Jerks
as though turned on and off again in rapid
succession. 1t is now believed that sensa-
tion Is what really acts in vibrations, and
that the nervous current by which we see
the flash Is reflected at the center of the
BRAN where the perception occurs return
Ing to the outer end of the seeing nerve
leturnlng again to the brain, and so on
IL mas been scientifically proven in France
that an impression Of intense light of al
most instantaneous duration is followed by
a sensation of great darkness, then light,
then lesser darkness. and so en-.
Electric Photography.
Herr karyall Of Vienna in a recent sci
entific publication Of that city is said to
have solved the problem concerning the
cause OF lightning photography-that is,
the imprint Of certain forms upon persons
as we'll as tnanimate things struck by
thunderbolts. With a powerful induction
coll Herr karyall produced an artificial
electric storm and allowed the spark there
from to strike a glass plate whose surface
was smoked. The black was put on In
such manner that each particle struck
by the electric spark. as 1t hit and scat
tered. was knocked from it's place Glasses
so treated were examined through a pow-
erful microscope and projected on a
screen. They were imprinted with various
tree, like and moss-like forms. With an
unusually strong current was made a fig
ure resembling a dim photograph of a
rustic fence with trees in the background
and birdlike figures flying about.
Lightning, of course. is no more than
such sparks as experimental with greatly
enlarged. A thunderbolt coming In contact
with persons skin leaves led marks
wherever the electric fluid enters Figures
OF supposed trees flowers. birds and so on
are those usually reported as having been
imprinted upon the human form in this