The Sun.
London, England, 1866-04-25 00:00:00

THE ATLANTIC CABLE.

There is the same difference between the appear-
ance of the Atlantic cable of this year and last as
between a white man and'a black. But this differ-
ence is purely external, and in no way applies either
to the conducting wire or the many coatings of
gutta percha and compound with which it is covered.
These are precisely the same as last year ; and in
shape, make, and size, the cable of to-day is iden-

tical with the one concerning which so many san-
guine hopes were raised twelve months ago. The
outer protection is composed of wires covered with

Manilla coating, as before, but as these are now
made of galvanised iron, the necessity for a tarry
covering is abolished, and the cable being at this
time put on board the Great Eastern at the rate of

more than a hundred miles a week looks like an

ordinary ship's rope which has just left the store-
room, and has seen neither pitch nor tar.

To trace the manufacture of the Atlantic cable
in its early stages, it is necessary to visit the gutta-

percha works of the Telegraph Construction and
Maintenance Company in the City-road. Here you
see the copper wire, as fine as packthread, as received
from Birmingham. When every yard of this has

been tested electrically, it is placed on bobbins, and
running through the glutinous mixture known as
Chatterton's compound, passes up a vertical spindle
which is fed by six other bobbins on which are the
same wire. These seven wires—six round the

central one—make nearly a perfect circle, and are

the medium of electrical communication. Every-

thing else about the cable is either for insulation or
for protecting the precious core, the diameter of
which is about that of a small pea. It is, perhaps,

unnecessary to add that the seven blended wires act
as one, and that while messages could be conveyed

through any of their number, even if the rest were
injured, it is as a single wire that the cable must be

considered for all practical purposes.
The preparation and application of the gutta-
percha coating is extremely interesting. In the vast
cellars of the City-road establishment massive blocks
of gutta-percha are stacked away in the primitive
state in which they left the natives selling them.
Idols, dragons, insects, monsters, and animals, are
all to be seen rudely fashioned in the plastic mate-
rial as it left the tree, and now hardened into what
resembles wood. You walk through groves and
avenues of gutta-percha, smell it on all sides, feel

it in the dim light whichever way you stretch oui

your hand, and hear without wonder of the immense
quantity required for the execution of such a con-

tract as the Atlantic cable. The different qualities
of this useful material are easily marked, and the
prevalence or absence of foreign matter easily seen
when bits are broken off. Inside it looks like hard
touchwood ; outside it resembles peat, or solid lumps
of bark. From the basement, where this mass of

material is housed, you pass to the next floor, in
the rooms of which it is being carefully made avail-
able. First, the vast blocks are broken up by a disc
armed with teeth ; then the mass is boiled in huge
cauldrons, until in colour and appearance it resembles
so many masses of liquified granite ; then, by ticker
and the cold water test, foreign substances are eli-
minated, until, after more boiling, it is placed under
hydraulic pressure, treated as a fluid, and comes out
cleared and purified of all appreciable impurity.
Then conies the process of mastication, which con-

sists of a series of teeth on a double roller being em-
ployed in working upon the gutta-percha until

is of the consistency of putty and the colour of cho-
colate. The same process is repeated with a single
roller masticator, and thus by repeated purification
and manipulation a perfectly plastic mass is ar-

rived at, which is proved to possess more highly
than any other the peculiar properties needed in
submarine telegraphy. The electric wire is first
passed through ;Chatterton's compound, which is
both insulative and adhesive, and attaches the gutta
percha to the copper, and finally into the gutta
perch itself, and then into cold water. This is the
first layer for the cable, and as soon as it is com-
pleted careful tests are again applied. The process
of dipping in the compound in the gutta percha and
in cold water, and of testing, is repeated several
times, until the cable is the substance of a slight
walking cane, and externally like so much gutta-
percha piping. It is then wound round drums in
lengths of 2,200 yards, which drums are deposited
bodily in tanks of water. Tests are constantly being
put, but the electricians appointed to certify before
the cable leaves these works, have it immersed in
water at a uniform temperature of 75 deg. Fahren-
heit. This is the contract test, and as the hotter
the surroundings of the cable the more trying to its
insulating power, it will be readily seen that the
trial is sufficiently severe. It is well known that the
bottom of the ocean is, in an electric sense, favour-
able both to copper and gutta percha, the one be-
coming a better conductor and the other a better
insulator the colder the water in which it is placed.

Gutta percha, too, increases in insulating power by
pressure, and it follows that the colder and deeper
the water, the more electrically perfect the cable is
hoped to become. Having been placed on bigger
drums it is now transferred in lengths of from four
to five hundred yards, to Morden Wharf, Green-
wich, where the remainder of its manufacture is
carried on. Here it is again tested at 75 de-
grees, and its gutta percha piping appearance soon
gives place to one more consonant with the
word cable. First it receives a coating of jute
yarn, put on by means of bobbins and a hol-
low spindle. This done, it is plunged in cold
water for from ten to sixteen hours, after
which tests are again rigidly applied. There are 32
tanks employed in this particular immersion, each
tank holding more than two miles of cable. We saw
some of the vast coil after it had been under water
several hours, and could discern no difference either
to sight or touch in its condition and that of the
cable just leaving the jute-giving machinery. From
these tanks it is passed through troughs downstairs,
and comes up to receive its final protection of ten
homogeneous galvanised wires, each of which has a
stout coating of Manilla. The cable is now complete.
It next passes into still more gigantic tanks, where
it is again socked in cold water, and where tests are
still constantly applied. From these tanks it is paid
out through a trough into the hulk stationed a few
yards from the wharf, and by this is carried to the
Great Eastern at Sheerness. The Amethyst, an old
Government frigate, was doing duty as hulk during
our visit; and has been built up and altered for her
present purpose until she looks far more like an ugly
Noah's ark than a ship of war. One of the unwrit-
ten laws of river life seems to be that strangers may
board and visit ships at anchor, without being given
into custody for trespass. The deck is open, and the
means of going below ample, so that under ordinary
circumstances any idle person might have access to
the cable without much difficulty while it is on the
transport vessel. To guard against such intrusion,
a substantial hut has been built upon, and covers a
great portion of the Amethyst's deck, and the slop-
ing roof of this, and its outhouse shape, look strangely
unshiplike when it is viewed from the land. Fast as
the cable can be paid in and stowed away does it
leave the works, and directly the Amethyst leaves
her place will be supplied by the Iris, the vessel act-
ing alternately as transport tender between the cable
works and the Great Eastern.
Not less interesting than what we have already
seen is another manufacture connected With the
expedition. We have traced every stagewire o.f flow
cable making from the little Birmingham
rest ship. The out-
the stout coil as paid into the g