The Sun.
London, England, 1857-04-22 00:00:00

'IIE GREAT ATLANTIC SUBMARINE

TELEGRAPH CABLE.

About a mile or so below Greenwich stands the
factory of Messrs. Glass and Elliot, where the
great submarine cable by which it is hoped to con-
nect England with America is.in rapid course of
completion. The Wig of wire, tons of hemp yarn,
and singular-looking drums from the Gutta Percha
Company, which are incessantly pouring into the
works, betoken the presence of an unusual kind of
manufacture, and this idea is quite borne out by
a mere glance over the premises themselves. The
first object which attracts the visitor's attention on
entering the yard is the vast bulk of cable already
completed. On each side of the path are two large
-circular docks or pits, in which about 600 miles are
piled away in four massive coils, each 35 feet in
diameter. It appears so manageable and so supple
as the men drag it from the building in which it is
manufactured that it is difficult to realise the fact
that the greater part of its bulk is iron wire, or
that a light and slight-looking rope of that kind is
intended to form a perpetual medium of communi-
cation under the 3,000 miles of one of
the deepest and stormiest seas in the
world. Such, however, is the result which
it is hoped to achieve, though whether it will do
so or not is quite another question, and one full of
doubt and difficulty. Before entering further into
the subject we may as well mention that the whole
cable is being constructed in two equal portions—
one-half being made at Messrs. Newell' works at
Birkenhead, the other at Messrs. Glass and Elliot's
at East Greenwich. The reason for this subdivi-
sion is that it was quite impossible for one manu-
factory to complete such a gigantic undertaking
within the allotted time. Each firm is bound by
contract to have 1,250 miles ready for shipment by
July, and as many miles more as they cm get com-
pleted in that time. - Already at the two manufac-
tories about 1,200 miles have been made. Glass
and Elliot produce at the rate of 70 miles per week,
but with an additional machine, in course of erec-
tion, they will, in a few days, be able to 'increase
that amount to .100 miles. We believe both firms
expect to have about 1,400 miles completed within
the period specified in their agreement. The in-
terest with which the progress of this great work is
regarded on both sides of the Atlantic will excuse
our giving a brief description of the various pro-
cesses through which the cable passes in its course
towards cordpletion. The conducting wire through
which the electric current will have to pass, consists
of seven No. 22 copper wires twisted into one
strand the thickness of a No. 13 w:re, or about
• 1-16th of a inch. This, we believe, 'is made by the
Gutta Percha Company, or at all events coated by
them with three folds of gutta percha, which in-
creases the diameter of the whole to of an inch.
In this form it is delivered at the manufactories,
coiled on wooden drums in two-mile lengths, with
a short piece of the copper conductor left out at
each end for the purpose of joining. As these ar-
. rive at Greenwich, the ends of the conductor are
carefully brazed togther, bound round with
• gutta percha, and so joined to the entire length
of the cable, which, all in one piece, is going through
the different stages of manufacture in the various
floors of the works. One end of the cable is con-
nected with a sand battery of 240 cells, which
maintains a continuous current through tbe whiele,
in order that the connexion and insulation of every,
new two-mile length may be ascertained with the
galvanometer as each piece is joined. The work-
man, therefore, who joins the ends, being in con
nexion with the current, is obliged to be insulated
from the floor with thick pieces of gutta percha
under his feet, to prevent his receiving severe
proofs of the perfection with which the current is
carried tbrougb. The wire thus coated and joined
is then wound off to the "serving" machine, where
it passes up the centre of a horizontal wheel, on
which are placed five bobbins, each of which is
supplied with many hundreds of yards of five-thread
yarn soaked in a mixture of pitch, tar, oil, and
tallow. As the wire moves slowly through this tbe
bobbin wheel revolves at the rate of 375 times a
minute, spinning the five strands of yarn tightly
about it, so as not to leave the smallest interstices
It passes from this through a gauge, which shows
its diameter to be 9-16ths of an inch exactly, and
the electric current with which it is in connexion
proves by the needle of the galvanometer that the
connexion and insulation of each fathom as it
moves off has been uninjured by the "serving"
process. It then only remains to "close" or bind
it up in wire. In this operation au enormous
amount of wire is consumed daily ; indeed more is
wanted than all the wire drawers in England can
supply, though to do so, they are now tasking their
powers of production to the very utmost. Of the
amount required our readers may judge by the fact
that, when completed, the whole cable will contain
enough wire to encircle the globe nearly 16 times,
or nearly to reach to the moon and back again.
The wire used for closing the outside is No. 22.
Seven of these are twisted into one strand, and 18
strands are twisted round the cable. The strand
machine in which the seven wires are placed re-
volves 450 times per minute, binding the seven
into one strong compact strand, the same diameter
as the conducting wire—viz., 1-16th of au inch.
Each of the strand machines, working night and
day, spins 98 miles of wire into 14 miles of strand.
There are 21 machines at work, which thus every
24 hours convert 2,058 miles of wire into 294 miles
of strand, which suffice to cover about 10 miles of
the cable. After the strand is spun it is wound on
to bobbins, and, having been carefully oiled and
passed through a number of gauges to insure its
bring of the requisite diameter throughout, the
bobbins are placed in the closing machine, which
is, of course, similar to that used for serving the
yarn, but very much larger. By the revolution of
18 bobbins round the cable the 18 strands of wire
are woven round it so as to form an almost CM-
pact metal case.
When their great size and weight are taken into
consideration these closing machines revolve at
fearful rapidity, and the centrifugal forca sometimes
causes the massive bobbins to fly off, carrying every-
thing before them. Fortunately as yet no casual-
' ties have occurred. The cable thus completed is
drawn from the " closing" machines at the rate of
30 feet per minute through a gauge of five-etliths
of an inch diameter, and then carried by revolving
wheels through a tank of hot tar, issuing forth into
the yard as fit as ever such a cable can be for its
submarine duties. In the yard, as we have already
said, it is coiled away in huge piles ready for ship-
ment, each day's labour adding some inches to the
height and bulk of the already ponderous masses.
The half of the cable made at Ne wall's works will
be shipped in July on board the Niagara Ameri-
can screw-frigate, the longest and largest vessel of
its class yet built. She will be accompanied for
the occasion by the Mississippi frigate. The line
made at Greenwich will be coiled on board the
Agamemnon, which will also be accompanied
by one of our largest steam-frigates to assist
iu laying down. The four vessels will pro-
ceed in company to the centre of the Atlantic,
where the ends of the cable will be carefully joined,
and each ship will make the best of its way to its
own shores, the Niagara steaming to Trinity
Bay, Newfoundland, near the Peninsula of Avalon,
and the Agamemnon to Valencia Bay, county of
Kerry, on the south-west coast of Ireland. By this
method the whole cable is expected to he laid in a
week or 10 days at most. Five miles of the cable,
where it joins in the centre, will be made of steel
wire, to enable it to bear the great strain at start-
ing. For 15 miles from the coast of Ireland it will
also be made of extreme strength and thickness, to
insure it from injury from ships' anchors. The
same precautions are also to be adopted at the other
extremity at Newfoundland, though only for five
miles' distance from the shore as the water there is
very much deeper. It is intended to sink the cable
across the extensive plateau or bank formed I y the
• course of the Gulf Stream on its northern side. The
greatest depth here is 2,100 fathoms, or nearly two
miles and a half. The average depth of the whole
route is 1,400 fathoms, or a little more than one
mile and a half. The direct distance from Valencia
to Newfoundland is 1,690 geographical miles, so
that between 400 and 500 miles of cable are allowed
for "slack" and casualties.
The Atlantic cable, of the construction and ulti-
mate destination of which we have thus given an
outline, is beyond all doubt a beautiful specimen of
maunfacturing skill. It possesses several essential
• requisS es. lts coat, we believe, is only 1001. per
mile ; its weight only one ton per mile. It is core
t racted for to bear a strain of 3 tons 2 cwt., but it
is stated to stand 4 tuna with safety. Its specific
gravity is between 3 and 4, its diameter is small,
and it is as flexible as an ordinary rope. These are
great advantages, but the sets off on the other side
are numerous and most important. In -the first
place, there is no wire for the return current, and
the conducting wire itself is ridiculously smell
(1-16th of an inch in diameter), when it is coni-
dered that it is intended to carry a current for
nearly 3,000 miles. The latter is a most serious
fault ; es also is covering the outside with so fi„e
a diecription of wires that three months, rust
will entirely destroy them. But the greatest fault
of all is that, in our judgment, the whole cable
.is constructed on a wrong principle. In a pre-
vious article on the subject of submarine telegra-
phie commueication we pointed out the errors
which have already led to the destrtiction of so
many cables, and the simple manner in which they
are remedied by Mr. Allan's patents. This Atlantic
cable, though with regard to I.ghtness and cheap-
ness a step in the right direction, is still not in the
right path. Whenever a cable is constructed with
spiral wires round a soft cord any severe strain in
paying it must, by stretching the outside wires,
either attenuate or break the copper conductor or