Peninsula enterprise. [volume] (Accomac, Va.) 1881-1965, 1901-09-28
LIGHTNING FLASHES.
HOW THEY ARE EVOLVED AND THE
ENERGY THEY POSSESS.
Inhabitants OF Compactly Built
Cities Have Little Cause to Fear
These Mysterious and Destructive
Balls From the Clouds.

Citics nave Lfttie cause 10 Fehr
These Mysterious and Destructive
Balls From the Clouds.
Without doubt lightning was the first
electrical phenomenon that was observ-
ed by human beings. TO this day II
remains the least known and least I'M
derstood Of natural electrical NANTES
tations except, perhaps, the aurora.
There Is a vast deal Of popular mis-
conception concerning the danger Of
lightning and the nature of 1t. The
lightning flash Is q discharge from a
cloud at a high potential with refer
ence to the earth. When the atmos-
phere Is charged with water vapor and
some eddy or current In It's colder up
per strata Is DETECTED downward, caus-
ing condensation, exceedingly minute
drops Of water are formed, each bear
ing an electrical charge. The consoll-
dalton of these into larger drops results
In very great increment Of the poten-
tlal Of the charge since the capacity OF
the drop varies with It's diameter and
the volume Of the drop with the cube
Of the diameter
The consequence of this is that II
takes, for example, eight drops consoli-
dated to make one Of twice the diane
ter Of the constituent drops, and the
charge on the surface Of the cOnsoll-
dated drop will be four times as great
as that upon the surfaces Of Its ele-
ments. In this way, rs the small wa
ter particles unite to form drops which
fall as rain, the potential of the charge
they carry increases until II attains
enormous values, and the lightning
fash leaps 10 the earth. which may be
regarded simply as a body Of very
great electrostatic capacity. The dis
charge. which Is called lightning. is
apt TO be more or less destructive, al
though the energy Of an individual
fash is perhaps not very great. Often
the conditions are such that the dis
charge takes OH an osclllatlng charac-
ter, producing violent surgings Of cur
rent. No very accurate measurements
have been made upon the current In
volved, but II is taken to be Of the or
der Of 1000 to 5000 amperes. The
electro motive force necessary to cause
q flash a mile long Is probably several
million volts. and Of course the power
Of the fash measured In watts is very
great, but its duration is correspond
ingly short.
Protection Of property and life from
lightning flashes has been a subject
that has entrained the attention of
natural philosophers since Franklin
sent up his historic kite. The net re-
suit of more than century Of attempt
to secure protection has been the light
ming rod in Its more or less inefficient
forms and the discovery that buildings
lie roofs and often metallic frames as
well. are practically immune from at
tack by lightning.
The total number OF deaths due to
In any given summer is COM
very small-ln the ratio Of
about one to each 100000 population in
the United States. In cities the de-
structive influence Of lightning is ex-
small, although occasional
fires are caused by 1t, especially where
gas pipes abound.
Protection of electric circuits from
lightning has been an interesting sub
ject for research for a number of years,
and several highly efficient devices
have been constructed for this purpose. |
Today lightning is little feared by the |
station superintendent and should be |
very little feared by any one. The |
time honored rule that 1t Is wisest to |
keep In the open and not seek the shell
ter Of trees is one which common pru-
1ence dictates. Recourse to the feath
err bed Of our ancestors, however Is no
longer necessary except to quiet the
nerves Of timorous persons. while the
ancient supersttfons regarding han
Hing steel instruments and sitting In
traits may be utterly disregarded. A
modern building In city is as nearly |
lightning proof and those in
t are as nearly absolutely protected
rom lightning as Is possible.-Electric-
Il Review.