Wessington Springs herald. (Wessington Springs, Aurora County, Dakota [S.D.]) 1883-1891, 1883-06-23
The Provision Of Thunder Storms.

Considering the immense destructive
ness of thunder storms at this season,
a recent communication to Nature by
Mr.. Ley, of London, on the subject Of
"sheet lightning" is practical and
timely. The phenomenon of "sheet
lightning has been long discussed by
scientists, but its nature has only
within q few years been determined,
and a too popular impression exists
that it is a harmless exhibition of cleo
trical force in the clouds. 1t is proba-
bly, owing to this misconception that so
many lives are lost by lightning stroke,
people generally not taking the noise
less electrical display as the forewarning
Of a thunder storm. Mr.. Ley very
properly rejects the notion that sheet
lightning is merely "a distinct form of
lightning unaccompanied by sound"
and shows that, on the contrary, as q
rule, it is ''the illumination produced
by a distant thunder storm" ut is
certain" he says, ''that the illumina-
tions of an ordinary thunder storm at
midnight, when there is nc moonlight,
have an average radius of more than
forty miles,"
This is a moderate estimate, as other
experienced observers give much
greater distances at which lightning is
visible. Mr.. Symons states his belief
that it is sometimes visible '.as far as
one hundred and fifty miles," which
may possibly be the case in the tropics,
where electrical storms in which the
lightning flashes extend over several
miles are formed at great attitudes.
The distance at which thunder is
audible, however, does not often
reach fifteen miles, though an ex-
IRENE case has been reliably reported in
which over two minutes ELAPSED be-
tween the flash and the thunder, indi-
eating that the former took place about
twenty-five miles from the observer. 1t
is obvious that during the raging of an
electrical storm its vivid flashes, espec-
tally at night in the absence of moon
light, may be seen at many points where
the thunder is %inaudible, and also at
many points over which the storm itself
will not sweep. But to all points living
in the storms path and at which the
silent lightning is visible the flashes
will serve as warning signals of the tenn
pests approach. With a little reflection
when such signals are displayed to an
observer it is easy to foresee whether
the distant storm will pass dangerously
near him. While our summer thunder
storms may not be translated from
point to point in the same way a regular
cyclone is, they progress SO slowly that
there is usually time enough between
their first seen flashes and their near
approach to discover their line of add
vance and to guard against the danger.
Of course this interval is greater if the
storm come up at night, when its light
ming can be seen at greater distances
probably in most cases one or two hours
before it arrives. AS all great thunder
storms occur only where sudden and
SHARP alterations of temperature are
impending, and the daily weather re-
ports show generally over what sections
such thermal changes will take place,
every man may be weather prophet
enough to put the above principles to
good use in protecting his family and
his property against the disastrous
effects of these storms.-N. Y. Herald.