The Anderson intelligencer. [volume] (Anderson Court House, S.C.) 1860-1914, 1894-11-21

may be G0Od lot HE III Iue lonS run,
but in the short run it is very aggra-
vating-if not more so. Nevertheless,
the best thing for us all to do now is
to be calm and serene. BILL ARP.
The Powers of the Upper Air.
The air will stand a strain Of about
5000 grains per square foot before
breaking. That is, the fash will
occur when the electrical pull amounts
to this 1.37 pounds per square foot:
For the energy Of a cubic mile of
strained air just before the flash we
have, then, about seventy million foot
tons. The average thunder-head or
cumulo-nimbus cloud is not mile
high, however. For a small cloud,
one hundred yards square, and dis
tant only quarter Of mile, we would
get about three hundred horse power.
Now fash even quarter of mile
long means potential Of many mil
lion volts. We cannot at present
measure this directly, but we can de-
termiDe the potential of the air within
certain limits on any day, thunder
storm or no thunderstorm.
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 q little farther from the
earth, ventured to use at times a
large kite, tin-foiled, and for kite
string some five hundred feet Of hemp
fish 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 I found it pos
sible to draw sparks, reading at the
same time on the electrometer from
minute to minute the electrihcation OF
the air in volts. In 1886 and 1887, in
some Investigations carried on by the
Chief Signal Officer, and more imme-
diately under the supervision of Pro-
fessor Mendenhall, I experimental at
the top of the Washington Monument,
at the time the highest edilice in the
world. The investigation continued
many months, but perhaps days on
which severe thunder-storms occurred
were most impressive.
It being beyond dispute the high
potentials can be obtained from the
air, the question naturally ensuing is,
Can we not use them ? With three or
four sparks large fruit jar can be
cleared of smoke with which it has
previously been filled. Perhaps ma
ture repeats this on large scale with
lightning, and clarifies foul, dust
laden atmosphere with these great
sparks. It may be, too, that these
flashes are all needed, and to attempt
to divert them would be unwise. BE
that as it may, we are living in an age
of "step-up'' and "step-down'' trans
formers an age when, for the first
time in centuries, we are perilously
near duplicating lightning. Until re-
Gently we studied lightning only in.
miniature. Professor Elihu Thomson
was kind enough to show me in his
Lynn laboratory, two summers ago,
some of his larger homemade light
ming. Indeed, potentials of 100000
volts are less rare to-day than poten-
tials 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 Heetlng
high potential lightning into a current
of lower potential and use it.
Professor Trowbridge, of Hazard
University, in a discussion of some
Photographic negatives, shows that
ssthe discharge follows exactly the
same path in air for three hundred
thousandths Of second,' and adds
that sit is probable that an ordinary
discharge of lightning of few hun
dred feet in length could light for an
instant many thousand incandescent
lamps if it were properly transformed
by means of step-down transformer.
The eye alone cannot give com
plete history of the myriad minor
flashes during thunderstorm. The
charred though to us intensely bril-,
liant 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 rapidly, ay, very rapidly,
nearly two hundred thousand miles
per second. Given proper resonator,
and the waves will do work. If my
reader keep every sense on the alert,
he may happen on some strange illus
tration of work done by lightning,
now all unsuspccted. In the tinkling
of the telephone bell, the blinking OF
an incandescent lamp, the melting of
fuse, or the tiny spark from gas
pipe or loose wire, is the constant
proof that there are more things going
on between heaven and earth during
thunderstorm than most of US dream
of in our philosophy. y.-Alenande Nc
Adie, in Harper's Magazine.