Evening capital journal. (Salem, Or.) 1888-1893, 1891-03-31
THE THUNDERSTORM.
An Explanation Of It's Origin and
Development.

A writer in the st. Louis Post Dispatch,
speaking of the development Of thunder
storms, calls them immense Leyden jars In
the sky, and supports his statement by ex-
planning their origin. Let us, he says first
OBJ. erve an average summer thunderstorm
as it is developing over us. The atmosphere
is sultry and oppressive. The heat of the
sun seems more penetrating than usual II
we look toward the sky we shall be likely to
note a lack Of its usual transparency.
Small inky-lool1ing clouds will be seen hav-
ing an indistinct and ragged outline The
clouds will increase in volume. Small ones
will unite forming larger bodies, and these
VIII rapidly grow in density and overcast
the sky. The heavy cloud masses will be
seen to approach nearer the earth. Occa-
sionally some section Of the cloud mass will
be Illuminated by lightning, and after an in
.erval of twenty or thirty seconds faint
rumblng thunder will become audible AS
the storm develops and draws nearer the
intervals between the flashes of lightning
and reports Of thunder will shorten, until,
whom the storm is at its height, many flashes
will be followed almost Immediately by
deafening crashes of thunder. BY this time
probably a heavy rain will be falling vary
ing at intervals in intensity. The storm will
continue from one-half to about two or
Jn1eG nOufS, WubH buc anu Juuu-
der will diminish and disappear, and the
ran-fall will gradually cease. When we now
venture out we shall encounter a cool, re-
fre8hing breeze, which will at once have an
invi goratng effect upon us. The rays of
the sun breaking here and there through
the clouds and falling upon the rain-drops
on the grass and trees will give to the sur
roundings the most pleasing aspect.
Having briefly described the thunder
storm as we all see 1T, let us now lnvestl-
gate what we have seen. While the thun-
der-storm was developing the air was OPP
pressive and we felt languid and uncomfort-
able This was due to the great amount of
moisture with which the air was saturated,
together with the high temperature. The
WCrm, vapor-laden atmosphere, expanded
by neat and rising 10 higher altitude, was
replaced by cooler air flowing in under it.
This accounts for the refreshing atmosphere
which we experienced. The great amount
of moisture in the air during the develop
ment of the storm accounts for the lack of
its transparency, and also for the indistinct
outlines of the clouds. AS the uprising air
reached higher altitude and encountered
cooler winds, its moisture was condensed
and we saw it in the form of clouds, which,
as the action continued, precipitated rain.
The most difficult phenomena to explain,
but which are at the same time the most in
teresting, are the lightning and thunder
Nothing definite was known about light
ming until Benjaplin Franklin demonstrated
by means of his well-known kite expert
ment, that lightning and electricity are
identical. His experiment is explained in
the following letter written by him on Octo-
ber 10, 1i52:
"Make a small cross Of light sticks of CO.
Har tbp az lpnu nc IN paaah tp n
corners of large, thin silk handkerchief
when extended. Tie the corners of the
handkerchief to the extremties Of the
cross so you have the body of a kite, which,
being properly accommodated with tail,
loop and string, will rise in the air like those
made of paper, but, being made of silk, is
filter to bear the wet and wind of a thunder
gust without tearing. To the top of the up
right stick of the cross is TO be fixed a very
sharp pointed wire rising a foot or more |
above the wood. To the end of the twine, |
next the hand, is to be tied a silk ribbon, |
and whore the silk and twine ioin a key |
may be fastened. This kite is TO be raised |
when thunder-gust appears to be coming |
on, and the person who holds the string |
must stand within door or window, or un- |
der some cover, so that the silk ribbon may
not be wet, and care must be taken that the
twine does not touch the frame of the door
on window. AS soon as the thunder-clouds
come over the kite the pointed wire will
draw the electric fire from them, and the |
kite, with all the twine, will be electrified, |
and the loose tilaments Of the twne will
stand ont every way and be attracted by an
approaching finger, and when the rain has
wet the kite and twine you will find the
electric fire stream out plentifully from the
key on the approach of your knuckle."
Having found that lightning and eleo-
tricity are the same, we must endeavor 10
explain in what manner this atmospheric
electricity is generated Many theories
have been advanced in explanation of this
question, and, while little is positively
known, the theory generally accepted is
that the electricity is generated by the fric-
tion Of the. liquid particles of vapor in the
air against each other, against the earth
and against the air. Some have claimed
that evaporation is the cause, but expert
ments have shown that wherever electricity
was generated by evaporation friction was
the real cause,
Lightning flashes appear IN different q
forms, Zig-zag lightning, as its name i'm
plies, is long irregular line Of light, and
IS tho most common form. Ball lightning
is round bail of lire, moving so slowly
that the eye can follow it, aud explodes
WIN lquu report Sheot hghtning Is
ii6nsed glare of light, which illumines the
edge or surface Of a cloud Zig-2ag light
ming is caused by the discharge of large |
quantity Of electricity passing through the
air, which, ON account of ITS resistance, be- &
comes compressed at various points aud {
turns the current aside The zig-zag path is
sometimes four or five miles in length.
lhe phenomenon Of ball lightning has
lever been satisfactorily explained al,
hough il is known 10 be the result Of an
intense discharge Of electricity.
Sheet lightning is the reflection OF zig-zag
lightning through the cloud mass, and may. | 1