Evening capital. (Annapolis, Md.) 1884-1910, 1884-08-30

rsaeu.omaema Of Electric Shocks
Cnuses or the ThundeTboAt.

In an article on the WOnucIs ~ CtS1
fricitv. a writer In the st. Louis Gtooe-
Democrat gives some interesting informa-
ton. He says that lightning-rods should
be of good size, connected with all prom
inent points. metal roofs, ETC., upon a
building which they are used to protect,
and be connected by well or cistern, or
sunk deeply enough in the ground to be
ALWAYS In contact with moisture. IL
properlv constructed, they are of service
in conducting away noiselessly and safely
the atmospheric electricity when 1t IS
accommodating In dangerous quantities.
If not properly constructed, they may
prove dangerous by inviting discharge
to house or other building which other
wise would have spent its force else
where. 1t may safely be predicted that
the day of the lightning-rod vender is
not vet over, and that he will affiict our
children's children as he has ourselves.
Relative to the intimate nature OF cleo
tricity as yet we know but precious little.
We do know. however that 1t is a
force of the same class as light, heat and
chemical affinity. 1t is a ''mode of
motion, = capable of being produced from
the other modes above enumerated, and
of being resolved into them at will. 1t is
not fluid, a material substance like a
solid or liquid, or a gas. and 1t cannot
show itself except In the presence OF some
form of matter. The amount of electri-
cal energy can be measured, and likewise
its intensity. The resistance 1t will
encounter when traversing a given con-
ductor can be calculated, and the amount
of light or heat into which it can be con-
verified is easily made known by mathe-
NAUTICAL computation. We have utilized
his subtle force in q thousand different
WAYS in the arts, but doubtless we are as
yet only on the threshold of electrical
science. While we are impatiently await
ing the glorious discoveries which we are
certain the near future has in store for us
it may be well to examine into what we
do know now of the thunderbolt, and of
its effect upon the human economy.
''As quick as lightning" is an expires
sion in every ones mouth, but every one
does not know the exaggeration of
which he is guilty when he utters it.
The duration of a flash of lightning,
according to the most accurate investi-
cations, is no longer than the millionth
of one second of time. This is much
swifter than sensation, than any animal
motion. swifter far than thought itself
The distance traversed by the flash is
variable, sometimes only short one, at
other times several thousand feet. The
signs of the passage of electrical energy
vary with the amount of resistance it
encounters. When it passes along a
good conductor of ample size it gives
no sensible indication of its presence
When it meets with much resistance, or
when the amount is largely out of pro-
portion to the size of the conductor,
electrical energy becomes converted into
other forms of force-heat or light, or
mechanical motion The enormous
amount of electricity concentrated in
clouds, the high tension at which it is
held, and the effects produced by the
resistance it encounters when it passes
along different media, account for all
the phenomena of thunder-storms
and of lightning stroke. The zig-zag
course of the flash is due to the differ
ent amounts of resistance opposed to it
by varying degrees of conductivity of
the different strata of air encountered.
Force of every kind follows the line
of least resistance, and this is no ex-
ception to the rule. The forked divis-
ions of the current are due to the same
cause.
Thunder is due to the disturbance occa-
stoned by the passage of the force through
resisting medium. If the discharge
traverses only short distance and is
pretty near the observer, the single loud
detonation-the thunder-clap-is pro-
duced. If the distance passed over be
long one, then the sound produced by it
In different parts of its course is heard
prolonged-the rolling or rumbIing takes
the place of the single explosive sound.
Reverberation from clouds and from
mountain sides prolongs the rolling noise
where such rejecting services are present.
Whenever there is discharge from
cloud to the earth there is at the same in
slant 'return shock, y or current from
the earth to the cloud. Frequently this
returning current is delivered from a vast
number of points, and is noiseless and
unobserved; but it may equal in volume
and intensity the downward discharge.
and may do just as much damage. Death
has been noted on MANY occasions from
the return shock, which may take place
at point where no rain is falling-per-
haps several miles away from where the
storm seems to be expanding its fury. In
such cases the effects are usually very
severe; death may result without any
marks OF injury being found upon the
clothes or body. In most cases of death
from lightning stroke the severity of the
injuries makes the cause Of death very
plain; but it must not be forgotten that
dc Il