Year: 1873

observed in the cable dispatches q no.
tice that the cable laid in 1865 chad
failed" at twenty minutes past twelve
o'clock on the day before; and that an
electrician would leave London in the
evening TO "locate the fault" They
Of course understood that il was the
mission 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 cablo buried under the sea the
cable had been injured or broken
And We have no doubt some OF them
have wondered how i. was possible
for the electrician to know, or to learn
tchere the fault or the break could be,
considering that some portions of the
wire were thousand miles distant
from his point of observation, and q
great deal of II buried deep from hu.
man sight two miles beneath the sur.
face of the sea. Yet every part Of
that long distance, and every fathom
of that abyss Of water, are within the
reach Of the electricians Instrumental
hands, and within the ken Of bis scien-
tifc eye. II is quite practicable for
him to "locate tho fault" or the break
within half mile ofils actual position,
no matter where it DO.


Although these far-rcaching powers
are among the great marvels Of mod
ern science, the means and tho princi.
Piles through which they are exercised
are among the simplest things when
seen and understood. A telegraphic
wire will transmit an electro magnetic
wave or "current," in proportion to
the square OF its diameter. The re-
SiStance to the transmission Of the
wave diminishes in proportion as the
square Of the diameter is increased
This is one law for the electrician.


Tho second is that the resistance to
the transmission of the wavo increases
in direct proportion TO the length Of
the wire or cab!o over which il is sent.
These two laws furnish the bases for
the electricians observations, calcula-
tions and results, He knows, to start
with, tho precise amount of resistance
that q mile Of the cable will oppose to
the transmission Of given quantity
of electro motive force. He has deli
cato and wonderful Instruments, made
by expert mechanics, that enable him
to measure this with accuracy for half
a mile or for ten thousand miles
Having this knowledge and these
measuring instruments, and having
control Of tho quantity of electricity
he is putting on the wire, he is able
to calculate to a nicely how many
miles OF the cable it is transmitted
over, before it encounters q greater
resistance than that which is due 10
the length and dimctcr of the cable
itself. At or near the end of that
of miles Of cable, though IL bo
a thousand miles from land, and two
miles under the surface Of the sen, the
"faulp or break the electrician is in
search of will be found.


Our readers should understand that
we arc not stating any nero hypo.
thesis. This real wonder and seem.
ing imposibility has been accomplish
ed 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
arc supposed by many people 10 be
wasting their lives about things Of
lttlo practical use, but whose works,
together with those of the skilled
me cchanics, who cooperate with them,
reaiiy move tho world along.


This particular student Of the laws
Of nature is Prof. Obm, Of Nuremberg,
Germany, one of several men whose
labors, like those of Oersted and our
American Prof Henry, have made
the Magnetic Telegraph possibility.
Tho delicate and wonderful instru.
ments by which those principles are
applied, and which enable the electri-
clan to extend bis reach thousand
miles out to sea, and To the bottom Of
the ocean abyss, have been at work
in one OF the most modest workshops
in this city for several years. They
arc the tools Of Philadelphia work
man, who now leads the world in the
manufacture of one important adjunct
in telograpby-a nearly perfect din
The simple device for work.
ing the ocean cable is there also.


This matter has been mentioned at
somo longth, for the benefit of the
boys and girls in our public schools,
who will see what grand and useful
results are accomplished by the appli-
cation OF the simplest principles Of
science, and that they may also un-
derstand that they need but rarely go
beyond their own city 10 find what
ever they may wish TO know, or TO
about scicpco, applied to
tho useful purposes Of li!e.-Pbiladel-
phia Ledger.