Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1855-07-26
nisfelIanfous.
THUNDER STORMS.

s'ormi ior ll&nt, moving with the lncOmprehen-
sible velocity of $4,000 miles in second, the
time that it takes to traverse any terrestrial dis
tance may he considered as nothing, but sound
travels only at the rate of about $50 yards, in a
second. The fash and the thunder are really
Simultaneous, but the former is instantly seen
while the other requires second of time to
traverse $50 yards therefore, the interval that
elapses between the two phenomena, being mul-
tiplied by this number, will give tho distance
of the storm.
Thus if the fash takes place six seconds be-
fore the thunder is heard, then 6 3SO=22SO
yards, which is the distance of the storm from
the observer. l
Let it be particularly remembered, that this
calculation regards discharge of lightning
that has happened, and it must not be consider
ed as a removal of the observer from danger, for
other discharges may rapidly happen much clo-
ser, as thunder clouds are frequently extended
over great terrestrial surface and very fire.
qacntly two or three flashes of lightning are
seen, apparently simultaneously, in the differ
ent parts of the atmosphere.
When lightning flashes in long irregular,
angular, gnarled or knotted stream, these ap-
pearances announce its passage through IN ex-
tensve volume of the atmosphere; but when
1t flashes in short. straight or direct line Of
liyid light, it may be considered to have disrup-
ted a comparatively limited portion of the at
mosphere.
In the first case, the flash would be seen some
time before the thunder would be heard, and in
the second case the fash would be instantly fol-
lowed by the thunder.
The tree in the background is supposed to
have determined the discharge of lightning from
a cloud lowering at a considerable distanse the
flash is therefore long and irregular; and
spectator of the stosm, if standing near the
tree, would first hear the thunder from the col
| lapse of the air near its summit, then from be-
yond this, afterwards from more remote por-
ton, and ultimately from the volume of the
cloud whence the Lightning first broke forth !;
the thunder, therefore, would not fall upon the
ear us one direct and crashing sound, but as M
irregular succession ofsounds or loud rumbling
noise.
This irregularity in the passage Of lightning
is sometimes SO considerable that the thunder is
actually lost to the ear at moment, and
heard again at another, and thus three or four
times successfully in the same clap u and this,
con joined with the reflection of the sound, or it's
re7erberation from mountain, hill and valley, at
one instant pealing loudly, at another, booming
gently, at length murmuring family, and ulti-
mately dying away, are extremely impressive
concomitants and attendants of the original
phenomenon of the fash
The tree in the foreground o f the engraving,
is supposed to have determined the discharge of
the lightning from cloud lowering at a little
distance; the flash is therefore short and regu-
lar, and spectator Of the storm, if standing
near this tree, at the moment Of the fash, would
bear the full thunder of the collapuing air, as
one loud and terrible crash, which in few sec.
onds after would reverberate from surrounding
objects, and ultimately die away in silence.
When the chemist causes electricity to pass
large and small intervals of air, the vivid sparks
in their disruptive transit, present upon mic
roscopic scale appearances precisely similar to
those Of extensive and limited flashes of light
ming. &
An appearance of two distinct flashes or
streams is very frequently produced at consid-
cradle distance from each other, when part Of
long sharp, angular fash is hidden by an inter-
vening cloud, and the sudden and universal fash
or /" sheet lightning appears to result from o
discharge which is more perfectly concealed.
The bright flashes which occur during sum
mer and autnmnal evenings, unaccompanied
by thunder, are Of this kind, and it is supposed
that on account of their vast distance form the
earth, the sound of the thunder must be lost in
its passage.
The appearance Of the heavens during thun-
der storm, the manner in which the clouds as
semble, and attract and repel each other, the
circumstance of their rising against the wind
and trayersing the upper regions of the atmos-
phere, in variety of contrary directions, are
phenomena which it is not difficult to explain
by reference to the general laws of electricity
Many of these have been discovered by the
great philosopher of the present day and regard
ing his extraordinary knowledge of Electricity
and Chemistry, it has been justly said, that,
"n point Of originality in devising experiments,
skill in carrying them into effect, and perspicu-
ity in tracing out and unraveling the complica'
Q ted relations of the new truths which are elic
/! tied, he stands, if not unrivalled OF least un'
surpassed.
a Upon known laws of electricity, as excited il
: the laboratory, the peculiar fringed appearance
# Of thunder-cloud may be explained, and alst
/. the Irregular portions which it projects toward
# the earth, while its upper surface is general,
d smooth and well-defned. @
|. We sometimes observe that number of sucl
O clouds of small dimensions, coalesce into lar
It ger one, moving swiftly in all directions, ant
J., darting flashes from one to the other, while th
I'll wind rises and often blows in squalls the light