Wyandot County Republican. [volume] (Upper Sandusky, Ohio) 1869-1903, 1871-12-28
Telegraphic Cables.

THE construction of telegraphic cable
is very interesting process. The first
step is making what is termed the core, or
conducting agent, of copper wire. The
earlier cables were generally made with
one conductor of thick wire, but it was
found that, to use popular saying, this
plan was the mistake of putting all the
eggs into one basket. If this thick wire
were to break-an accident to which it
was very liable in the act of laying it
there would have been a breach OF continu
ity, the tongue which talks under the ocean
would have been struck with paralysis.
In order to avoid this, strong central
wire of the best copper is used, and round
this number of fine wires are twisted.
By this method the fracture of the central
or base wire is no longer of importance,
as the small wires, even if there was a
strain upon the cable, would carry the
current. Indeed, we have seen cables
that have been broken and dragged asund-
er many inches, still Geographically per-
feet, for this reason. The twisting of the
fine wires round the central one is very
similar to the making of ordinary rope.
In order to insulate the conductor, thin
slips of India-rubber ribbon are carefully
plated over it. When the whole length
has been thus plated, in order to secure
the edges the cable is passed through Il
tank of liquid India-rubbcr, which ce-
ments them together The core has now
to be armored, when protection is re-
| quired for deep or rough seas. This is
done by laying stout iron wires Longitude
nally and parallel with the core ; but these,
again, have to be protected against the ac-
ton of the salt water, which is done by a
plating of hemp, coating of tar com
pleting the process. When excessively
rough or rocky shores have to be guarded
against, the shore ends of the cable arc
protected by several additional layers OF
accidents happen to cables after they have
been laid, the cable has to be fished up
and the fault found and spliced.
The finding of a fault in the deep ocea1
may appear to the reader difficult, nay
an impossible operation. For instance
to have to pay in the Atlantic cable, ant
examine it inch by inch, in order to dis
cover, possibly, a mere pin-hole, woult
seem to be a very labor of Hercules. Bu
science is equal to the task; the electrician
sitting in his room at his instrument, b,
means of delicate appliances, can estimat
to within mile or two the distance g
which the fault is to be found. Nevertht
less, every precaution is taken to preven
these ultimate appeals to science; for tn
lifting of a deep-sea cable is no child
play, and the cost is great; consequent
every precaution is taken to secure tb
E perfect insulation of the cable while it
, being manufactured. Before one of thes
marvellous talking wires is accepted b
the purchaser it is required to test up
certain given point; and in order to s.
,, cure this there is an artisan rejoicing III
! der the name of the fault finder. When tn
! insulation is used, the liquid percha
! moulded on to the conducting wire as it
: passed through die, hydraulic pressul
! forcing the material round it in har,
! dense pipe, which loods very like choc
! late. The wire thus insulated, as it
: wound off. passes through the hands
q this fault-finder, whose fingers, educate
). by practice, feel any little air-hole tn
v may have occurred in laying on Il
= gutta percha. Directly this is found,
# hot iron is applied to it, and it is stoppe
!, -Haype1's Weekly.