The Republican. [volume] (Oakland, Md.) 1877-current, 1894-09-13

POWERS OF THE UPPER AIR.
Tho Tremendous Energy Stored Away in
the Clouds.

5000 grains per square foot before
breaking. That is, the fash will occur
when the electrical pull amounts %
this l37 pounds per square foot. For
the energy of cubic mile of strained
air just before the fash we have, then,
about seventy million foot tons. The
average thunder-head or cumu, o-nim-
bus cloud is not mile high. however
For small cloud, one hundred wards
square, and distant only d quarter of
mile, we would get about three hun
dred horse power. Now a flash even .
quarter of a mile long means a poten-
tial of many million volts. We cannot
at present measure this directly, but
we can determine the potential Of the
air within certain limits on any day
thunder storm or no thunder storm.
In 1885. at Blue Hill observatory. and
in subsequent years, we measured the
potential of the air with insulated
water-dropping collectors, after the
methods of Thomson now Kelvin and
Mascart. The top of the hill is six
hundred feet above the surrounding
country; but with Franklin's idea of
| reaching out little farther froI1 tae
earth, | ventured to use at times d
large kite, tin-foiled, and for kite
string some five hundred feet of hemp
|, 'hsh-line wrapped about with fine un-
| covered copper wire. During thunder
storms the sparkling and sizzling at
| the electrometer end of the kite string
were incessant and startling. And
even on cloudless days l found it pos
sible to draw sparks, reading at the
same time on the electrOmeter from
| minute to minute the electritication Of
| the air in volts In 1886 and 1887, in
some Investigations carried on by the
chief signal officer, and more immedi-
ately under the supervision of Prof.
Mendenhall, | experimental at the top
of the Washington monument, at that
time the highest editice in the world.
The investigation continued many
months, but perhaps days on which
severe thunder storms occurred We're
most impressive.
1t being beyond dispute that high
potentials can be obtained from the
air, the question naturally ensuing is:
Can we not use them? With three or
four sparks a large fruit jar can be
cleared Of smoke with which it has pre-
viously been filed Perhaps nature re-
peats this on a large scale with light
ming, and clarifies a foul, dust-laden
atmosphere with these great sparks
1t may be, too, that these flashes are
| all needed, and to attempt to divert
them would be unwisc BE that as it
may, we are living in an age Of step
up and ''step-down' transformers: an
age when. for the first time in CEN
turtles. we are perilously near dupli-
eating lightning. Until recently we
studied lightning only in miniature.
Prof Elihu Thomson was kind enough
to show me in his Lynn laboratory,
two summers ago. some of his larger
| homemade lightning. Indeed poteu-
tials of 100, 900 volts are less rare to-day
than potentials of 5000 volts were FIVE
years ago All who saw the Thomson
and Tesla exhibits at the Electrical
building Chicago, will easily believe
| that it is within our power TO turn the
ieeting high-potential lightning into
current of lower potential and use i.
Prof Trowbridge, of Harvard uni
versity. ina discussion OF some photo
graphic negatives, show, tha5 the
discharge follows exactly the same
path in air for three hundred-thop-
sandths of a second. - and adds that 1t
is probable that an ordinary discharge
of lightning of few hundred feet in
! length could light for an instant many
thousand incandescent lamps if it We're
, properly transformed by means OF a
step-down transformer
The eye alone cannot give a complete
history of the myriad minor flashes
| during a thunder storm. The charred,
! though to us intensely brilliant, crack
in the air which we call lightning is
| but great splash in the ether ocean.
The waves and ripples come tumbling
| along in all directions, spreading rap
idly. aye. very rapidly, nearly two hun
! dred thousand miles per second. Given
! a proper resonator, and the waves viii
| do work. If my reader keep every
| sense on the alert, he may happen on
| some strange illustration of work done
| by lightning, now all unsupported. In
! the tinkling of the telephone bell, the
| blinking of an incandescent lamp, the
melting of a fuse, or the tiny spark
| from a gas-pipe or a loose wire, is the
constant proof that there are more
things going on between heaven and
! earth during a thunder storm than
! most of us dream of in our philosophy
/ Alexander McAdie, in IIarpers Maya
| zine.