The Wellington enterprise. [volume] (Wellington, Ohio) 1867-188?, 1880-03-18

for the purpose Of opening and closing
the circuit, or, in other words, making
and breaking the contact. The cones
lose their magnetism the instant the
circuit is broken. An Armature, also
of soft iron, is suspended near the ex-
posed ends of the cones to which
spring is attached to pull it away from
the cone when mot under the infiuence
of the magnetic effect. Thus the arma-
ture il caused to vibrate correspond |
ingIy as the key is worked to open or !
close the circuit The effect on q sim
liar instrument at the distant end Is
precisely the same; also, all interme-
diate Instruments in the circuit. In
this manner the dots and dashes are
transmitted from any part OF the line
to all other instruments.
The cable system of telegraphing
differs, necessarily, very much from
that of the land wires. 1t will be re-
membered that the first cable, laid in
1859, was q complete failure, owing to
a lack of experience. Battery power.
supposed to be sufficient, was employed
without satisfactory results. More
battery was added without success, un-
til it was discovered that the battery
was SO powerful that the conducting
wire in the cable was burned up, and
the consequence was q complete failure
-a result a. costly in q pecuniary sense
as it was mortifying and discouraging
to the protector. Repeated experiments
at length demonstrated that less battery
and more sensitive instruments must
be employed. The rejecting galvanom-
eter is the only instrument at present
with which long cables can be success
fully worked with battery OF low ten
sion. 1t consists of q needle formed OF
q piece of watch, spring, hree-eighths
of an inch in length, the needle sus-
pended by q thread of cocoon silk with
out tension. The needle lies in the CEN
ter of an exceedingly delicate gal
vanometer coil. A circular mirror of
silvered glass is attached to the needle,
and reflects, at right angles to 1t. in the
plane of its motion. It is SO curved
that when the light of lamp is thrown
through fine slit in it, the image OF
the slit is reflected on q scale, about
three feet distant, placed little above
the front Of the flame.
Defiections to the extent of half an
inch, along any part of the scale, are
sufficient for one signal. This instru.
ment is necessarily used in q darkened
room. Condensers are used at both
ends of the Atlantic cable. The term
condenser has long been used among
electricians to denote an arrangement
equal to a Leyden jar of enormous ca
pacity. The condenser is charged from
q small battery and discharged into thu
cable. The transmitting keys are con
veniently arranged to dischage from
\ these condensers into the cable cur
rent of either polarity, and the needle
at the distant end of the cable responds
but in opposite directions, as the cur
rents of different polarities are dis
charged through it. The reflection
thrown on the scale moves to the righ
and left, from which the reading !
taken. The eye can easily distinguish
at any point on the scale. to which tn
spot of light may be detected, the be
ginning and end Of signal.
other with wonderful rapidity. Tn
usual speed for messages is from twelv
to fifteen words per minute, but whel
l the operators are conversing with csc
1 other twenty 10 twenty-five words pc
minute are usually attained. As to tn
velocity of electricity, it takes abou
. three seconds in q cable across the Al
I lantic for the current to reach its fu
strength. The current does not arriv
l all at once, but grows gradually from
minimum to q maximum. For the dat
which forms the subject matter OF thi
2 article the writer is indebted to Mr.
K. Newton, the electrician Of the Wes
ern Union Company. It is an astonisf
> ing fact that 30 keen are the perceI
!; tions of some telegraphers that the
q can detect the " sending" Of men the
t have worked with even after lapse
: years, with the same facility that q
:. expert tells the authorship ofhandwri
ing by the formation of certain letter.
-CI1cSsnati Commercial.