Marshall County Democrat. (Plymouth, Ind.) 1855-1859, 1857-07-16


ming and artificial electricity
t He also erected on his house in Philadel
. phia, an iron rod, which he brought il
communication with a series of bells in hi
room. and when the zelectricity would b,
attracted by the rod, it caused the bells t.
) ring and warn him of the opportunity tc
continue his experiments. By these cx
periments he also ascertained that there
was t~o kinds Of electricity or lightning
one he termed positive and the other mega
tive; but he found that clouds were NOR,
frequently charged with the positive kind
while the earth is generally negatively
charged; herce discharges of lightning
from the clouds to the earth frequently
take place. Ii is also asserted that in Ger.
tain electrical conditions of the two, light.
ming viii sometimes ascend from the earth
to the clouds.
We once saw tree under high bluff
; that had been shattered in this way, as was
evident from the appearance of the spin.
ters and numerous fragments produced
by it.
Electricity accumulates in greatest in
tensity at prominent points; the negative
electricity of the earth is greatest on noun
tain SUBMITS, clouds, as we have said, be.
ing in general charged with positive elec,
tricity, an attraction will consequently be
exerted upon and around such SUBMITS.
Thunder seldom proceeds from soita-
ry, isolated cloud. But when two clouds
appear, one below the other, and one con-
tanning greater quantity Of electricity
than the other, the electricity in the one
most fully charged, in seeking an equiib.
rum, will pass from that cloud to the 9TH
er. and in Its passage through the interve-
ming air. which is not so good a conductor
as the cloud. an explosion takes place, pro-
ducing all the phenomena of lightning and
thunder. Under similar circumstances,
lightning is attracted from the clouds to
the earth and strikes rees, men, and hor-
ses and oths. terrestrial bodies.
There is always mote or less time that
intervenes between the periods when the
flash of lightning is observed by the eye,
and the sound of the thunder reaching the
ear. This is owing to the fact that light
travels faster than sotnd. Light commu
nicaled al the rate of 100000 miles in a
second of time. and sound, in ordinary
conditions of the atmosphere is esti-
mated to travel only at the rate of 100
feet second. The distance that a thunder
cloud is from us may be estimated by the
number of seconds that elapse between the
time of seeing the fash, and that of hear
ing the thunder; thus if five seconds.elapse
the distance will be 5. $40 feet, for SIX Sec
conds, $500, etc. DC.
Lightrings are resolved by NJ. Arago,
into three glasses. First, the gig zig,
which presents The appearance of narrow
well defined threads or lines of light in
such course that clearly expresses its
name. Zig zig lightning seldom appears
between two clouds, but geneally mani
tests itself between cloud and some terres
trial object. Second, those lightnings
which appear ditfused over extensive sur
faces and have the appearance of a mo-
mentary light seen through plate of glass
and are commonly called sheet lightning"
or ''heat lightning" Owing to certain
state of the surrounding atmosphere, and
the relative state and position of the clouds,
this lightning frequently appears unac~
companied with thunder. and is sometimes
called still lightning. Lightning that moves
through the air at a comparatively slow
rate, appearing like luminous ball, or a
globe of fire. This Is called ball lightning
Thunder, or the sound that accompanies,
or follows lightning, Is caused by the
sudden displacement of the air by the ex-
plosion, forming vacuum. and the air sud-
IDENTIFY rushing in again to fill the vacuum
produces the sound we call thunder; but it
may be more correctly explained by sup
posing that the electricity in passing through
the air congresses successfully the air ly-
ing before it, whence there results series
ofcontractions and dilations, which, extend.
ing to distance, produces the long rev.
erberations These reverberations are con-
tinued, and their effects upon the ear var.
led by the ecto from the clouds. and in
this respect much depends upon the pos
ition of the clouds in their relation to the OBJ
sever.
The duration of the roll of thunder is US
ually from three to forty seconds. The
distance at which thunder can be heard is
from ten to thirty miles.
While engaged in writing thesforegoing,
we received copy ofthc New York Trib-
une, containing very interesting com
vn,,n,oot:ox g., N. Tohn W,oo of Ioooo