The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1865-08-07

s2G IN
The cable now being laid is twenty hundred miles
in length and and one-eighth inches in diane
ter. The weight of the is said to be over
five thousand tons, and the Great Eastern is the
only vessel which could carry it. The "core, or con-
ducor il made of fine copper wires twisted into
single strand, and insulated by compound known as
Chattertons Around this core four layers OF guta
percha insulated with the some compound, and IN turn
enclosed by eleven strong iron wires each one OF which
is carefully wound with Manila thread and saturated
with tar thus at protecting the gutta percha ana
adding strength to the cable Its strength is equal TO
bearing strain of seven and tons As CON-
pared with the tensile strength of the cable OF 1888 Is
several times greater While the electrical tests show the
core Of the present to be infinitely superior to that
of the cable OF 1853
TnY SHORE ENDS OF THE CABLE.
The shore ends of the cable Of different sze being
as large as wrist and the strongest cables ever
manufactured for telegraphic purposes The weight per
mile of the shore ends Is very little short of half the
weight Of ordinary railway metal. The shore end at
vaentia bay thirty miles in length, while the New
foundlaud end is but three miles long
THE CABLE TANKS.
The cable was stored finished, in three Immense
iron tanks built upon the lower deck Of the Graat
Eastern and after being placed in them and the tanks
flied with water, thoroughly tested by the elecri
clans of the expedition The first tank was located in
the forward part of the ship, and was fyone feet in
diameter The mdship tank over the boilers, and
was tysix six inches in diameter and the after
one was tyeight feet in diameter The first contained
coil of six hundred and thirty miles, the second eight
hundred and forty mil s, and the third eight hundred
and thirty miles Before the Great Eastern left
cl.oa tI,a uir ,uch
submerged in the three tanks as it ever will be at the
bottom of the Atlantic with this difference that the pres
sure of the depths Of the ocean will materially
improve the condition OF tbs cable b, the compression OF
the Qua pcrcha In these three tanks tho temperature
and quantity Of water kept precisely equal and
series of electrical tests TAKEN in order to obtain
standard of what the condition OF the cable should be
while paying The contents Of the three tanksthat
Is the entire length OF thousand i've hundred miles
Of cable-were coupled up while the the Great
Eastern was still at Sheerness and signals were
sent through morning and evening. These signals
served to show the insulation and conductivity oil
the wire bc almost absolutely perfect even in an cleo
trca sense II was stated that the forward COLI would
be the first payed out whereas tho fact Is that as com
mon sense would suggest, the sternmos, coil was the
first delivered" then the bow coil and lastly the one in
the centre of the ship by these the vessel was,
with the assistance Of the quantity Of water
aud coal on board kept proper trim throughout the
whole voyage.
THE PAYING OUT MACHINES.
The great object Of incres, is the paying out APP
paratus THIS beautiful machine Is an improved aud ex-
tended copy far general principle is concerned Of
that used board the Agamcmnon during the first
memorable attempts. Its improvements and modihca-
TONS however, are very great Though stronger and
much larger it is very much lighter being almost en-
rey Of wrought iron. II has six leading wheels around
which the cable passes In deep before reaching
the main wheel drum, from which Il was finally
submerged Each groove In these six wheels Is sur
mounted by what Is termed jockey pulley sliding
VIII cl, which keeps the rore down in the groove and
prevents overriding getting out OF place. The main
drum Is sbou, seven diameter, and in paying out
has three coils Of cable around it, with guiding piece Of
wrought iron pressing them sideways to keep them
compac.,y together As the friction the gudcr
expected to he great and constant duplicate pro
vidcd In case of heating, which could be put IN gear
with the rest of the machinery without the
slightest stop any part. second drum was also
ntted, in Of anything going wrong with the first
Each of these drums is fitted with distinct set OF
simple aud ingenious brakes invented by Mr. APP
pod for the first expedition The ordinary condition OF
these brakes maintains sufficient check upon the drum
to keep strain OF thirty forty hundred weight upon
the rope going out but provision has been made for sud
den rise of the ships from giving the cable
strain that requires the instant removal Of the brakes to
relieve it, This is accomplished by dynamecr placed
on the cable after leaves the paying machine and
before 1t passes over the wheel into the Atlantic
This dynsmcter Is only heavy wheel resting on the
rope but fixed in upright frame, which allows IL TO
slide freely up and down, and this frame Ii marked
the figures which show exactly the strain in pounds
| on the cable. Thus, when the strain is low the
cable slackens and the dynameter sinks low with III
when, the contrary, the strain is great the cable
drawn taut" and II the dynameter rises TO It's fu
height When sinks too low, the cable generally runs
away too fast and the brakes have be applied 70 check
IL; when on the contrary rises rapidly the tension
is dangerous and the brakes have TO be almost opened
| TO receive It, The simplicity Of the arrangement fo'
opening and shutting the brakes is the most beautiful
Of ALL Opposite the dynamcter s placed iiler wheel
and the man in charge Of this never lets 90 nor SLACK
| ems his attention for instant, but watches the rise
and fall Of the dynamete saor at the wheel wache'
his compass single movement Of this wheel to the
right would put the brakes on turn to the eft opens
them good and experienced brakesman will generally
contrve 10 avoid either extreme Of high low strain
though there are few duties connected with the laying
Of the cable which are more anxious and more respon
sble than those connected with the management OF the
| brakes.
| THE OPERATING OBSERVATION-DISCLOSURES GAL
| vANoMRTER.
The galyanometer consists Of coil OF exceedingly fine
copper wre covered with silk, in the centre Of which
suspended small MIRROR about three eighhs Of an inch
long. To the back of the mirror is cemented small
piece Of magnetzed iron which is suspended by single
fibre Of silk just as from the cocoon Opposite
the gavanometer is placed paraine lamp, bearing be-
fore IL horizontal SCALE The light from this lamp
directed through slit in the SCALE and Is thrown upon
the face Of the Mirror which reflects back the scale
spot Of light BY the movements Of this spot TO the right