The democrat. [volume] (Weston, W. Va.) 1868-1874, 1873-05-05
NOW thn Monder Is Morked.

The readers OF the Ledger doubtless
observed in tho cable dispatches n no.
tice that the cable laid in 1855 chad
failed" at twenty minutes past twelve
o'clock on the day before and that IN
electrician would leave London in the
evening to "locate the fault" Theyof
course understood that it was the mis-
sion Of the gentleman mentioned to go
to the shore end Of the cable on the
coast OF ireland, to ascertain at what
point of the two thousand miles Of cable
buried under the sea the cable had been
injured or broken. And We have no
doubt some of them have wondered how
it was possible for the electrician to
know, or to learn, iOhcre the fault or the
break could be, considering that some
portions OF the wire were O thousand
miles distant from his point Of observa-
ton, and II great deal Of it buried deep
from human sight two miles beneath
the surface OF the sea. Yet every part
Of that long distance, and every fathom
Of that abyss OF water, arc within the
reach OF tho electricians Instrumental
hands, and within the ken OF his scien-
tifc eye. 1t is quite practicable for
him to " locate the fault or the break,
within half mile OF its actual position,
no matter where IL be.
Although these far.reaching powers
are among the great marvels Of modern
science, the means and the principles
through which they arc exercised are
among the simplest things when seen
and understood. A telegraphic wire
will transmit m electromagnetic wave
or " current, ''in proportion to the square
of its diameter. Tie resistance to the
transmission Of the wave diminishcs in
proportion rs the square Of the diame-
ter is Increased. This is one law forthe
electrician.
The second is that tho resistance to
the transmission Of tho wave Increases
in direct proportion to the length OF the
wire or cable over which it rs sent.
There two laws furnish the bnsos for
the electrician's observations, calcula-
tions and results. He knows, to start
with, the precise amount Of resistance
that mile OF the cable will oppose TO
the transmission OF o given quantity Of
electro motive force. Ho has delicate
and wonderful instruments, made by
expert mechanics, that enable him to
measure this with accuracy for half q
mile or for ten thousand miles. Having
this knowledge and these measuring in
struments, and having control OF the
onantity OF electricity he is putting on
the wire, he is able to calculate TO u
nicely how many miles Of the cableit is
transmitted over, before it encounters q
greater resistance than that which is
due to the length and diameter of the
cable itself. At or near the eud Of that
number Of miles Of cable, though 1t be
thousand miles from land, and two
miles under the surface OF the sea, the
"fault" or break the electrician is in
search OF will be found.
Our readers should understand that
We are not stating any mere hypothesis.
This real wonder and seeming imposi.
bility has been accomplished again and
again. The principles through which
it Is accomplished, are the discovery OF
one Of those quiet, studious men, who
plod about in their laboratories and
workshops, and who are supposed by
many people to be wasting their lives
about things OF little practical use, but
whose works, together with those OF the
skilled mechanics, who cooperate with
them, really move the world along.
This particular student OF the laws
Of natnre is Prof. Ohm, Of Nuremburg,
Germany, one Of several men whose
labors, iike those Of 0ersted and our
American Prof. Henry, have made the
Magnetic Telegraph q possibility. The
delicate and wonderful instruments BY
which those principles are applied, and
which enable the electrician to extend
his reach o thousand miles ost to
sea, and to tho bottom Of the ocean
abyss, have been at work in one OF the
most modest workshops in this city for
several years. They are the tools OF q
Philadelphia workman, who now lends
the world in the manufacture OF one
important adjunct in telegraphy-a
nearly perfect i'insulator." The simple
device for working the ocean cable is
there also.
This matter has been mentioned at
some length, for the benefit Of the boys
aud girls in our public schools, who
will SEQ what grand aud useful results
are accomplished by the application OF
the simplest principles OF science, and
that they may also understand that
they need but rarely go beyond their
own city to fnd whatever they may
wish to know, or to understand about
science, applied to the useful purposes
OF life.-PliLadeLphiaLe Ledger.