Evening star. [volume] (Washington, D.C.) 1854-1972, 1900-07-28
IN OCEANS DEPTHS.
How Submarine Telegraph Line is
Laid.
PROTECTING THE ELECTRIC CURRENT
Ingenious Methods of Determin-
ing the Route.
CONSTRUCTION OF A CABLE

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"ii''eh ioF Inc Evening star
| The events of the last two years have
given an increased interest in the remoter
i narts of tho ,,obo .ha. - - -. -
| ,,-,aos,,-o,. So no mas never oeei 50
| as ho" AIMING our people Inc
| fniippines ana the Transvaal have ceased
| being mere geographical facts. and have be-
| come real places of which We knox, so,,a-
| thing and fro,,, IT., 49, -, -
'ntiis' anu from "hlch we demand news
| Dur,,o- .ha -. = nv
| world has hoo, u,..o,;rr, ,r,.;a,,S,, -
| drama +b.t 10 hatr.r o,,,e..s a.. Ut, =
revealed Inv tn. co.,. .,a,,,-.. 49,
| ceived ord j.; tha,raa, 90
ceramic cables Ia ~, ,,,,.,r.. tle
| minds that forrnar1,, -, -. - 40
| tbou,bt ''eA
| II is s.,x,
| s'idhse now re" people know any
| thlng OF the oceanic Geographic service. A
| vague idea that it is carried on by cables
| is about all that the ordinary, na-so,, no.,
| sesses but What III 10 pei sui pos-
Grated or what difficnItiss H. IL, az nov 1t Is OPP
| its construction are ali nntnoan ~
| bulk of welI-informad neonia r-bo a " ~
of them are generally so incunbere6 uri,b
| technicalities as TO he elr,nst ,';,Ii, ~
| to unnrofessionaI rssdars go Siii ~ ING oie
quence they are wranned in more ,,,,otar,
| than are any things Thai an.ar vt -,
day life.
| Most people think that thar. L. $500
| difference hetw suhne rne 80 ~ NJ mo- .,
egraphy than there is hstwa GU ,aiiu -. Vel
| head and an underground troIIay L. -.
| this Is not true They are absoIutai,r a.;
| tinct and have i,ttta ,nora g.; ooo. us
| have a great railway svstar IN . man
car line, if SO much. Roth taIearanb,c ot,se
| TENS usa e,actrio -. i teiesf aphlc sys-
lie,
| railway and the horse Cav Iina a. oooh Ine
| that move ON a track hut al, e. ne
| ferent - e-'e - uii-
|
ho ana ocean TeieRraDhy.
In land telegraphy a wire IL RIM be+uaap
| the terminal noints and oo,,,aa.os -,
| su;,,h,o ,,.-. eeeeu Will
a,'., uineies ior sendlng and re-
eeHihs the signals. The wire Is usually
OF iron and is supported by poles high
| enough above the earth to save n fror,
accidental interf.ra,oa I'm
fitted With orIas ;', me poies are
where The So, 5st .ta uiators at the points
he mn ..IeaI.sat at tt 81 tndl there may
line ia wa+nbe5 i me current, ana the
moIes1.tHn,a ns CLOSELY 10 guard 1t from
jured IF axnarisnoa i sba-I, ~ II ~ De IN
| first selected is unsuitable another can
De taken with little extra trouble or ex-
mmst ha - - iol SO with cable Its wires
through which Tho coo 80 ~ ei' elope
| trate, for the electricity would he lost IL
the conductors had a bare spot. The cable
la-s ne ne On the bottom and risk the dan
precise snot can he go - 1t pe ihJured. the
calculations and uben fo or,ry py uiiilc tI
must he souobt o., -. u 'ite cdoie
face from a Senth narbaps re -, tLe SUI
sides these difIcnitias +hIo ~; it.es. De
that is based on a nronartr So oiie
itself Every one knows +b.t ., ~ 49,
current meets rosistenoo M. q s.Iohs
oped as in the comnon inoan5o.o - uef s eI-
trio light. Now notbing hat is re-.
known is a perfect condSc+or "a -
strong current is passed through the hast
ones we have the conductor Vii CO.. -
and some electric;tv is Iost ~ e. ah ~
does not amount to anvtbing fnr a. 80
are not Continuous for verv araat AZ
| tances but have ..relavs', et.o Us
where the weakened current fs ratnforce5
This cannot be dome on a cable ava 49,.
tricians were puzzIed To find soma ,,ears
by which a current could be caused to ira
verse several Thousand rnilas az co,raar
wire without being so powerfuI as To 4.
stroy the cable. II was found that the
current was so weak when its iournaI,
ended that it could not move an ordinary
Morse instrument SO a system was oe-
vised that employs apparatus of another
sort and Of exquisite sensitiyeness
tn. S.r,..
"
In order to understand why route for a
proposed cable is sought with such care,
the structure of the cable itse,f sbo,1a 10
known-for on its safety depends the sue
cess of the enterprise. cable consists of
core of wire that is really the import
ant part of the whole, and a covering of
some insulating and protecting material.
ine eoie Is hiaae OF stranos OF copper
from 70 To 400 pounGs ner ,, III fnr Sc tta
shore ENDS that have to stand the surf are
much stronger and heavier Than tho daen
sea portions, The stranded form is mora
flexible than A solid rod and is NOT 60 ant
to be broken in laying The core is coated
with a mixture of resin tar and e1,tt,
percha. known as .Chatterlon,s comnonnd ;,
that is 10 act as a cement and hold tb. in
sulation firmly to the wires
The Insulating material nust con,n-,, With
MANY reouirements- II must NOT conGuc.
electricity and must prevent leakage, as
much as possible; It must be thorousbiv
waterproof. for the sea water will Soon
corrode the conner IL # reaches II and viii
steal the current IL there he the smallest
hole through which it NAV reach The wires
1t must resist the chemical action of tbe
water on itself and n must he fexibIe and
tough so that the cable may be coiled into
~ r,,I,,ss -, i boia snip anu run oHer