The Sedalia weekly bazoo. [volume] (Sedalia, Mo.) 187?-1904, 1891-06-16
SUBMARINE CABLES.
How the Great Ocean Telegraph Lines Are
Made and Protected.

SSSses
How the Great Ocean Telegraph Lines Are
Made and Protected.
According TO the latest report of the
International Bureau Of Telegraph Ad-
ministrat;on the submarine telegraph
system OF the world consists of l20,070
nautical miles of cable. Government
administrations own i2. 5s4 miles while
;O7. $40 are the property OF private COM
panies. The total cost OF these cables
is in the neirhtorhood of 5000. 900, 0O0
The largest owner of submarine cables
is the Eastern Telegraph Company.
whose system covers the ground from
England to India, and comprises 81 $50
miles of cable The Eastern extern
sion. which exploits the far East, has
IL, ?5s miles more.
Early in last year the system of West
African cables, which started from
Cadiz o2ly six years ago, was completed
To Cape Town, so that the Dark Cont
nent is now completely encircled by
submarine telegraph. touching at nu-
merous points along the coast More
than -. OO0 miles of cable have been re-
uuired to do tn S, and several compa-
MES with more or less aid from the
British, French. Spanish and Por.u-
guese Governments, have participated
in carrying out the work.
The North Atlantic is spanned by no
less than eleven cables. all laid since
1870, though think not all are working
at the present time; five companies are
engaged in forwarding kilograms be-
tween North America and Europe, and
the tota, length OF the cables owned b.
them, including coast connections. Is
over so. 600 nautical miles
| Let US frs: see what submarine
cable is, and how It is made. To do
this visit must be made to the enor-
nous factory on the banks Of the
Thames a few miles below London.
Here the birth Of the cable may be traced
through shop after shop machine after
machine The foundation of all Is the
conductor, q strand % seven fine cope.
wires. This slender copper cord is first
hauled through a mass of sticky, black
com pound. which causes the thin coat
ing Of gu.:a-percha applied BY the next
machine to adhere to it perfectly. AID
prevents the retention Of any bubbles
Of air in the in;erstices between the
strands. or between the conductor and
the gu,ta-percha envelope.
One envelope is not sufficient, how
ever. but tie fill thickness of insulat-
ing material has TO be obtained by four
more alternate coat:nCs Of sticky COM
pound and plastic gu'ta-percha The
T. in .nd and has
developed into ''core." Before going
any further the core is coiled into tanks
filled with water. and tested IN order to
ascertain whether il is electrically per-
feet i. e., that there is To under leak.
age of electricity through the gutta-
percha insulating envelope
The tests are made from the testing
room, replete with beautiful and elab-
crate apparatus. By which measurements
finer and more accurate than those
Ieyen OF the mos. delicate chemical bal
arce may be made. Every foot Of core
is tested with these instruments. both
before and after being made up into
cable. and careful records are preserved
Of the results
After the core has been all tested and
passed, the manufacture OF the cable
goes on The core travels through an
other set Of machines. which first wrar
! it with thick serving Of tarred jute,
and then with compact armorin4 o.
iron or steel wires, of varying thickness!
according to the depth Of water In which
the cable Is intended to be laid Above
the armor;ng in order to preserve thu
iron from rust as long "a possible. Il
applied covering Of stout canvas tap
thoroughly impregnated with . pitch
like compound. and sometimes the irol
wires composing the armor are separ
ately covered with Russian hemp as Al
add. tional precaution against corros!on
-Scribner's Magaz