The Sun.
London, England, 1858-11-19 00:00:00

NEW SUBMARINE CABLE.

There is nothing whichillustrates so forcibly t
complete infancy of the science of submarine tele-
graphy as the important discoveries and.improve-
ments which are daily taking place in all that re-
lates to it. Morse's recording telegraph, with its
cumbrous modes of signalling, is not long for the
present age, and hardly has the printing telegraph
been made known ere a code of signals is being
arranged which promises to develope to the
greatest extent of which it is capable the rapidity
of transmitting messages in any language by a few
short signals. Most of our readers will recollect the
objections which have been urged, on mechanical
grounds, over and over again, against the principle
• ple of havpig submarine cables covered with
wire in spiral folds. The inconvenience and
risk of such a method have been generally
admitted—the greatest being the liability of the
wire either to become untwisted or form " kinks."
A simple arrangement to obviate all these difficul-
ties has now been brought forward in a patent rope
by Messrs. Stevenson and Binks, which so adds to
the lightness and strength of the cable, and so ad-
mirably facilitates the work of submerging, that it
appears astonishing why it was never thought of
before, especially as its principle of construction
has been known for five or six years at least. The
improvement simply consists of plaiting the outer
covering of wires in a braiding machine, precisely
in the same manner with wire as sashline or pic-
ture-cord is made withcotton. A plaited submarine
cable made on this plan, and closely woven, has its
outer 'covering wound round it with the firmness
and almost the closeness of a gun-barrel, while by
regulating the size of the wires used an ample de-
gree of flexibility is secured, especially as a rope so
made cannot -possibly form in kinks, as is the case
with those enclosed in the spiral strands. The spe-
cimen which has been made consists of 12 plaits,
each plait being composed of six galvanised iron
wires of No. 15 gauge. The diameter of the whole
wire is an inch, its weight is as slight as that of the
Atlantic cable, while its cost is very little more,
though by the plan of plaiting the wires its
breaking strain is increased to no less than 7+
tons. One of the strongest objections which was
urged against the Atlantic cable by every engineer
of note was the certainty of the outside spiral wires
stretching under ',tension, while the gutta percha
could not. It was contended that the effect of any
severe strain must break the insulation in minute
plucts, and of course, expose the conductor to all
those electrical derangements which, from some
cause or other we have recently seen the Atlantic
cable undergo. None ever attempted to deny that
this mechanical defect in the principal of the outer
spiral wires was really of the most serious kind, and
it was only met by saying that a cable so covered
should not be exposed to strain of any kind. In a
plaited wire the only effect of- the strain would be
to compress to the utmost the inner core and con-
ductor without the least possibility of elongating
them.
In the specimen of which we speak, an inch in
diameter, the outer wires are plaited so completely
round that the section shows them resting as one
piece, and thus in the centre, instead of one con-
ductor, ample room is left for four. These are in-
sulated not by gutta percha, as has hitherto always
been the case, but with indiarubber. This, though
electrically speaking a worse insulator, possesses
many peculiar and important advantages, the
greatest being that it is totally impermeable to
water under any pressure. Of course it would be
impossible to coil a submarine cable made with a
plaited outer covering, and it would have to be
stowed in a vessel in straight lines, running fore
and aft. This, however, would be no disadvantage
—on the contrary, in many cases it would be de-
cidedly preferable, and the only reason which up
to the present time has made it . absolutely neces-
sary to coil all submarine cables is their extreme
liability to "kinks" in any other mode of stowage
—a liability which even the coiling often fails to
overcome. All risk from a foul wire breaking and
stripping the cable would be equally done away
with on the new principle. In every point of view,
therefore, as regards strength, lightness, durability,
capacity for carrying several conductors, and free-
dom from almost all the accidents to which past
submarine cables have been exposed—the plaited
wire covering is the greatest improvement which
has yet been made. Of course, according to the
size and strength of the wire required, the number
of plaits may be varied from six to twelve, while
the size of the wires themselves regulates the
amount of flexibility of the whole.