The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1873-03-22
How the Wonder is Worked.

= -" - "t+tF|% - ~ ~ ANtFtN
The readers Of the Ledger doubtless OBJ.
served in the cable despatches Of yesterday
a notice that the cable laid IN 1865 chad
failed" at twenty minutes past twelve
O'Clock on the day before; aud that an
electrician would leave London in tho
evening to sslocate the fault" They Of
course understood that II was the mission
of the gentleman mentioned to 60 to the
shore end Of the cable on the coast of
ireland, 70 ascertain al rlat point Of the
two thousand miles Of cable buried under
be sea the cable had been injured or bro
zen. And we have no doubt some Of
hem have wondered how it was possible
or the Electrician.to TO know, or to learn
,chere the fault or the break could be,
considering that some portions Of the wire
we're thousands Of miles distant from his
Joint Of observation, and great deal Of Il
'uried deep from human sight two miles
beneath the surface Of the sea. Yeteyery
part of that long distance, and every
athom Of that vast abyss Of water, are
within the reach Of the eleetfician's 3 insfyu-
mental hands, and within the ken Of his
cienti6c eye. L is quite practicable for
lin TO "locate the fault or the break
within half mile Of its actual position,
10 matter where 1t be.
Although these far-reaching powers are
mong the great marvels Of modern science,
he means and the principles through which
hey are exercised are among the simplest
hings when seen and understood A tele-
Taphic wire viii transmit an electro-mag-
letic wave or "eurrent" in proportion to
he square Of its diameter The resistance
o the transmission Of the wave dimaishes
n proportion as the square Of the diameter
$ Increased This is one law for the cleo
rician. The second is that the resistance
o the transmission Of the wave increases
n direct proportion TO the length Of the
wire or cable over which it is sent These
wo laws furnish the bases for the electri-
iian's observations, calculations and results.
de knows, to start with, the precise amount
f resistance that mile Of the cable will
ppose TO the transmission Of a given
luantity Of electro-motive force. He has
lelicate and wonderful instruments made
" expert mechanics, that enable him to
MEASURE this with accuracy for half
nile or for ten thousand miles. Having
his knowledge and these measuring instru-
nents, and having control Of the quantity
f electricity he is putting on the wire, he
is able to calculate to nicely how many
niles Of the cable il is transmitted over
'efore it encounters greater resistance
han that which is due to the length and
liameter Of the cable itself At or near
he end Of that number Of miles Of cable,
'hough it be thousand miles from land,
md two miles under the surface Of the sea,
he ''fault" or break the electrician is in
search Of win be found
Our readers should understand that we
ire not stating any mere hypothesis. This
ZEAL wonder and seeming impossibility has
,een accomplished again and again. The
principles through which it is accomplished
ire the discovery Of one Of those quiet,
ltudious men, who plod about in their lab
'ratories and workshops, and who are sup
,osed by many people to be wasting their
ives about things Of little practical use,
,ut whose works, together with those Of
he skilled mechanics, who cooperate with
hem really move the world along. This
articular student Of the laws Of nature Is
Professor Ohm, of Nuremburg, Germany,
ne of the several men whose labors. ike
hose Of Oersted and our American Pro-
essor Henry, have made the Magnetic
Telegraph possibility. The delicate and
wonderful instruments BY which those
principles are applied, and which enable
he electrician to extend his reach thou
sand miles out to sea, and to the bottom
# the ocean abyss, have been at work in
me of the modest workshops in this city