Five Mile Beach weekly journal., 1915-07-09
THUNDERSTORMS
Scientific Explanation of
How They Occur.
ELECTRICITY IN THE CLOUDS.

Tbs Processes by Which the Masses of
UnequaIIy Charged Vapor Are
United, the Lightning Flashes Gen.
Grated and the Downpour Started.
Lightning is the result of electric dis
sharges from the clouds, says the Elec-
hical Experimepter in printing what
II calls "a thunderstorm primer"
avery cloud, like every other object,
contains electricity. This makes no
disturbance so long as the quantity
contained Is normal. When the guam
#itv becomes greater than normal the
nbiect is positively charged; when 1t
BECOMES less than normal the object Is
negatively charged. The equilibrium
AZ the electric force in the clouds is
disturbed by corporations from the
surface of the earth, by changes of
4emperature in the atmospheric vapor,
IN chemical action on the earth's sur
bee and by the friction of volumes of
s,r Of different densities against each
ather.
When clouds charged with the oppo-
ZfR GlPClE1CllIGo dPPAOoNh3 bhO AOASCo
zlsh toward each other and combine to
4~estore. the state of equilibrium, for all
nodies charged with opposite electrici-
los attract each other. Between the
Slouds is air, an excellent nonconduc-
Tor. through which the electricity has
a force a passage. The violence with
which 1t does this produces the light
hing and the accompanying crash of
fhunder.
Clouds are good conductors, while the
air about them is a nonconductor;
therefore the electricity accumulates in
the clouds. 1t is probably this cleo
4ficity which prevents the particles of
water from uniting together and falling
Down in the form of rain.
Imagine two clouds near to each 9th
a. In the sky, one positively and the
4ther negatively electrified, for there
cannot in all nature be such a condi-
lon as that of n body positively ex-
fited without the coexistence of an
Eother body negatively excited. If the
Positively charged cloud were all alone
IL the sky the circumjacent atmos-
here would assume the negative func-
Ion. But as the other cloud is near by
IL becomes negative, and both are mu-
thally attracted. They approach each
other until the space Of air between
hem can no longer resist their electric
zension, when the discharge takes
olace.
The equilibrium of the clouds being
fbus restored, there is nothing to keep
De particles of water apart; they Goa
see into drops and fall as rain
When only the clouds are involved
lie equilibrium h quickly restored by
a few flashes and the storm Is over.
hen the air also is involved it con
kInues to charge the clouds with cleo
#icity, and the discharges continue I'M
IA the various strata of air are brought
! znto their normal state.
Sometimes, when the clouds are
charged with an opposite electricity to
fhat of the earth, q discharge takes
HIace from clouds to earth or from
5 rth to clouds. It is only when there
Is a great disturbance of the electrical
\ <orces that the lightning flashes to the
led nth or vice versa.
{The flash and the thunder peal are
Simultaneous, and we see the one be-
ore we hear the other because light
#hves move far more swiftly than
sAund waves. The peal of thunder is
instantaneous, but ONE to us as a
! I'll through being echoed from clouds
8f mountains. The noise is caused by
ne vibrations of the air rushing to fill
NJ the spaces where the electrical dis
4 large has rarefed 1t and condensed
i<z vapors.
Lightning is ZigZag when it travels
through a long distance, because it
eompresses the air, which i~nterferes
WIth its direct course. 1t is straight
WDen 1t passes through only a short
Instance. 1t is forked when. being re
SE'sted by the air, it divides into two or
Hfnree points. 1t is sheet when the flash
s too distant to be visible, and its re
Rnection alone is seen.
BY remembering that sound travels
e quarter of a mile in a second. while
l&zsht travels so swiftly that we see 1t
zAf UNANIMOUSLY, we can tell how far
so1 a thunder clap is. If we hear a
A1pnder clap four seconds after seeing
1ne fash we know 1t is a mile away.
hpr such calculations our own pulse is
4kuf1ciently accurate measure of time,
11f the pulse of an adult beats about
re a second. A person under forty
snpuld count five beats to the mile; a
feFson under twenty should count six
1thts to the mile.