Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1857-05-09
THE OCEAN TELEGRAPH.

HE OCEAN IELEUHAPH.
Fol the instructive paper which follows we are
indebted to Lieutenant BROOKE, of the Navy
gentleman who has rendered invaluable service to
science, and whose name we may say, almost with
out figure is already known throughout the depths
of ocean; for it is by means of his invention that
" deep-sco" soundings are now taken, and that the
soundings made for the Ocean Telegraph
His reflections and suggestions on that interest
ing subject are entitled to great respect, and we
have no doubt that they will be carefully consider
ed BY the officers engaged in laying down the cable
There who doubt the possibility Of laying
telegraph cable the Atlantic l think it may be
easily shown, however that the eventual accomplishment
of the project is much within the limits of probability
1t true that have but little experience in this kind
strengthening yet kindred branches there have been
many interesting facts developed bearing directly upon
this subject We know, for instance that not unfre-
quenty four five miles of small twine less than one
tenth of inch in diameter have been veered into and
dragged by heavy weights to the bottom of the sea and
that in instances these lines have been recover
ed from depth of nearly four miles.
Suppose that, without attaching weights you to
pay this twine freely cut and on with the ship
you might go from Nef York to Ireland and if the line
were slack enough to fneet the demzsasf aisSe cur
rents it - yhen This Irvine would REQUIRE
no reguafhg machinery, but it would scarcely sink to
the bottom.
Now, IN some experiments in the Gulf Stream under
the direction of Lieut. Walsh six miles of steel wire
veered out and much of it recovered before break
ing You might then but for its rapid descent span
the ocean with wire; it would reach bottom QUICKLY
but would require the minute attention and various
appliances to regulate its velocity and guard against
waste SO that what require is to combine it were
the strength of iron with the ghness of twne to con-
sruot cable that may be strewn upon the water find
its way slowly the bottom while the ship runs at her
highest of speed Thus the greatest resistance to the
descent of the cable may obtained and the tendency
to slide away diminished This most favorable of all
conditions only limited by the probable strain arising
from the action of unequal currents.
Gutta percha, the insulating material affords ready
of diminishing the specific gravity of wire cable
1t is that in adding guta percha the surface expos
ed to the action of these viii be increased but
there is evidence their absence the depth of thousand
fathoms. This learn by microscopic examination of
specimens obtained from the bottom of the sea- But
apart from this, there is compensation afforded by the
movement of the cable ITSELF will sink the direction
of its inclinaon in other words, it will away from
the ship in opposition to her course and this rereaing
of the cable may be termed its back-set" 1t is evil
dent that while this action tends waste the cable
it will more than supply the demand of the current
This back-se, which with heavy cable presents the
most serious obstacle, with lighter becomes an ele
ment of 1t is the opinion of several eminent
men that the simple copper wire clothed with gutta
percha most nearly fulfs the required conditions But
there are certain contingences-lah to sbrasion
from the rolling of the ship and in yeering it would
even be endangered by the heel of boot; hungry
shark would instant therefore it is necessary
to protect the gutta percha.
nossd If Of the atlantic Telegraph Company CONF
percha forming which supports spiral col
seventeen twisted strands of iron WIRE each composed of
several smaller wires.
1t remains to be SEEM in practice whether these vari
materials have been most advantageously combined
Suppose that the copper and iron wires straight
and parallel in that case since the relative ducy of
these metals is about four to five in favor of the cop
per- the iron wires would practically bear the strain
evng the copper and this without regard change Of
form in the of gutta percha But in the cable
in process of manufacture the outer wires make
whole turns to the foot becomes them serious oues-
ton whether by strain the pressure Of five six
thousand pounds to the square inch the win be
compressed altered in form The water penetrating
the iron wires win surround each part Of the cable
and on them, individually exert its powers of compress
SION fthe guta percha yields the iron wires win become
loose, will extend and the strain will come the straight
copper drawing it and although it may yield twenty
per cent of its length without breaking any such pre-
cess involves risk.
1t is stated that india rubber is less compressble than
water, and it may be inferred that gutta percha
bles it in that respect well in others But
this comparative incompressibity of india rubber is
only observed when that substance entirely immersed
but parts Of the cable viii be above water, and guua
peroha of nearly the specific gravity as wser,