The Hancock Jeffersonian. [volume] (Findlay, Ohio) 1857-1870, 1865-06-30
Volume l2-Num6er 8.

ity, lose That electricitv after time.
In speakipg of insultion we must
therefore be understood to mean an
approximate conditions but the CD.
Proclamation in the case of the new
Atlantic cable comes so neer to per-
lection, t'ot this rough, tarry rope is
q scientific wonder.
The last dying pulsnton of the old
Atlantic cable was forced through it
by means OF 8 galvanic battery con.
sisting Of two hundred and forty cells.
The submarine telegraph from Lon.
don to Amsterdam is habitually
worked with q battery of fifty cells,
and such q battery is commonly used
for the other submarine lines of Eu.
rope. Signals have been repeatedly
sent through more than thirteen hun.
dred miles of tie cable now on board
the Great Eastern, by means Of one
cell. Galvanic currents so feeble
that they could not have been felt by
the hand, and might have been passed
harmlessly through n circnit com.
pleted by the operators tongue, can
be used to convey messages along q
line Of cable that would very, nearly
stretch from London to St. Peters
burg. Over needle instruments, such
as those in ordinary use for land tele-
graphy, a current from one cell would
he powerless. faH .A.4 .rlf.A
To record such faint pulsations OF
electricity, it is necessary to use Pro.
fessor Thompson's mirror galvan.
ometer. This beautiful Instrument
consists Of a mirror about the size of
iourpennY piece, made of micro.
copic glass, and so thin that it weighs
only grain. On the back Of this
mirror minute magnet is fixed, and
thus supplemented it 10 suspended by
a silIIen fiber in the heart of coil OF
wire, 90 that any current passing
through the coil defects the magnet
and the mirror along with it. A ray
Of light reflected by the mirror falls
on n scale, distant about eighteen or
twenty inches, and revealsits faintest
movements. Different combinations
OF these movements represent the diff
fercnt letters OF the alphabet, and
thus the apparently erratic wander.
ings Of a ray of light are made to con-
vey Intelligence. An instrument of
this kind is constantly used to test
the cable, az IL Ia hauled on board;
aud If any fault had existed, II could
not have passed without detection -
Up TO this time, when there are on
board the ship and alongside 1870
miles Of cable, no fault has been dis
covered. 4s.-.a
THs IAIMERsIoS. l.t.s
The machinery Cor, having out Is
not vet on board, but Is heing put to-
| gethcr nj the Greenwich works. The
process ofimmersion will take about
A fortninht The herinninRlof The
fshore end will he laid bv small ves-
sci, which will meet the Great East
crn about twenty miles from the
/ Irish coast The calle will then he
passed on hoards connected withthat
In the great tanks, and the big ship
win begin her voyage. To the
/ initiated, this process Of cutting and
Joining the cable very mysterious,
I but the engineers. who are used no ths
work, face it without any hesitation.
The Joints do not really endanger eli.
thsr the insulation or the strength OF
the cable, az wherever they are made.
the external aud conducting wires are
spliced along considerable length
sometimes not less than thirty yards
and the guttapercha carefully put on
in separate layers, firmly pressed to.
gether by means OF warm irons.
The completeness OF the Joint is test.
cd hy LAYING il in an insulated metal.
lie ves sci containing wstcr, and as.
certnined, by means OF tests applied
to this vessel, whether any electricity
escapes from the joint as the current
Is passed along the cable,
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