The Lambertville record. [volume] (Lambertville, N.J.) 1872-1968, 1873-04-09
nov. TIE WoNDER rs woHKED.

HOW THE WONDER rs WORKED.
The readers of the Ledger doubtless OBJ
served in the cable dispatches recently no
tice that the cable laid in 1866 ''had failed =
at twenty minutes past twelve o'clock on the
day before; and that an electrician would
leave London in the evening to s'locate the
fault" They of course understood that it
was the mission Of the gentleman mentioned
to go to the shore end of the cable ON the coast
of Ireland, to ascertain at sohat 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 electri-
clan to know, or to learn schere the fault OF
the break could be, considering that some por-
tons of the wire were thousands of miles dis
tant from his point of observation, and 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 vast abyss of water, are within
the reach of the electricians Instrumental
hands, and within the ken of his scientific eye
1t is quite practicable for him to ''locate the
fault y or the break within half mile of its
actual position no matter where it be.
Although these far-reaching powers are
among the great marvels of modern science,
the means and the principles through which
they are exercised are among the simplest
things when seen and understood. A tele-
graphic wire will transmit an electromagnetic
wave or s.current in proportion to the square
of its diameter. The resistance to the trans
mission of the wave dimiaishes in proportion
as the square of the diameter is Increased.
This is one law for the electrician. The second
is that the resistance to the transmission of
the wave increases in direct proportion to the
length of the wire or cable over which it is
sent. These two laws furnish the basis for
the electricians observations calculations and
results He knows, to start with, the precise
amount of resistance that mile of the cable
will oppose to the transmission of given
quantity of electro motive force. He has deli
cate and wonderful instruments, made by ex-
pert mechanics, that enable him to measure
this with accuracy for half mile or for ten
thousand miles. Having this knowledge and
these measuring instruments, and having con-
troll of the quantity of electricity he is putting
ON the wire, he is able to calculate to nicely
how many miles of the cable it is transmitted
over before it encounters greater resistance
than that which is due to the length and di-
aneter of the cable itself. At or near the end
of that number of miles of cable, though it be
a 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 impossibility has been
accomplished again and again. The principles
through which it is accomplished are the dis
covery of one of those quiet, studious men,
who plod about in their laboratories and work
shops, 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 nature is
Professor Ohm, of Nuiemburg, Germany, one
of several men whose labors, like those of
Oersted and our American Professor Henry,
have made the Magnetic Telegraph a posi-
bility. The delicate and wonderful instru-
ments by which those principles are applied,
and which enable the electrician to extend his
reach thousand miles out to sea, and to the
bottom of the ocean abyss, have been at work
in one of the modest workshops in this city
for several years. They are the tools of
Philadelphia workman who now leads the
world in the manufacture of one important
adjunct in telegraphy-a nearly perfect in
sulator." 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 and girls in
our public school, who will see what grand and
useful results are accomplished by tho appli-
cation OF the simplest principles OF science, and
that they may also understand that they need
but rarely go beyond their own city to find
whatever they may wish to know or to under
stand about science applied to the useful pur-
poses Of life.-Phita. Ledger.
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