Crawford avalanche. (Grayling, Mich.) 1879-19??, 1895-04-11

MoouonsooI t00oousVs
The making OF nm ocean cable Ii {
task involving great amount Of
skill and mechanical ingenuity, and
1t is something to the credit of the
first cable makers that their pattern
has not greatly changed in thirty
years. When the Commercial Gable
company--which, as the most purely
American of all the companies,
makes an excellent subject for illus.
tration-decided to lay q new Allan.
tic cable last year the work was
intrusted to the firm OF Siemens
Brothers, OF Woolwich, London. As
this firm has constructed no less
than eight OF the eleven, cables now
linking Great Britain and the United
States its methods of manufacture
may be watched as typical of the
best. sA
The first care Of cable manufact-
urer Is to secure the very best ma
terials. The copper wire, which
forms the heart and essential part of
the cable, must be of the purest
metal, since the purer the metal the
higher its standard of condpctivity
will be. Every strand and every
coil OF wire that goes into the cable
is expected to reach certain stand
ard, and to such q degree of excel
lence Is the smaking Of copper wire
for electrical purposes brought now
adays that the material submitted is
more frequently above that standard
than below. Tho single wires hav-
ing passed the test for purity and
conducting power eleven similar
standards are taken and spun into q
slender rope in lengths of one mile.
Gutta percha insulation is then APP
piled in sheets prepared from the
raw material as it comes to hand
from Singapore and other Malay
ports. These sheets are wrapped by
experienced hands so firmly and
smoothly round the wire that not an
air bubble can remain between the
copper Ind the insulator. The core"
Is then ready to be submitted to a
galvanometer test to ascertain
whether the insulation is perfect,
or as nearly perfect as that
very elusive agent, electricity, will
permit. That test having been sat-
isfactorily passed workman. whose
sole business it is to attend to the
joining of the lengths of cable,
spices the ends of the mile lengths.
Again the isolation test is applied.
The galvanometer indicating no very
appreciable loss Of electricity, even
under the strain of an alternating
current of 5000 volts, the core is
passed into the hands OF the sheath
ers, whose care it is to surround the
copper and gutta percha with a more
substantial protective covering be-
fore they are submitted to the rough
action of the sea And now the
weight and size of the cable become
applicable. Already each mile length
has in it some 500 pounds Of pure
copper and $40 pounds OF pure gutta
percha. Over, this is spun cote Of
jnte yarn weighing nearly 600
pounds to the mile. Then the cable
is made the center Of twisted sheath
of steel wires of the stoutest kind,
averaging more than 1000 pounds to
the mile. And finallysa compound
Of tar is laid over the whole, which
brings its own weight OF 800 pounds
to the mile. After the tar is applied
the cable is coiled and left to soak in
tanks of water until such time as
the cable ship shall be ready to lay
it in its last resting place. Such a
cable as this is made at the rate of
fifty to fifty-fve miles per twenty
four hours.