The New York herald., 1876-08-18

uuiteu tue OpiOOn tndt tnus luT icas usc
has been attended with very unsatisfactory results,
and that no method OF construction yet devised has
maintained underground wires In working order ior
any length OF timer
The underground system is now almost entirely con-
nned to the large ctes and in these Is used only TO
very limited extent The wires are brought INTO the
cities as far tho railway stations poles, and
tnenco arc carried underground TO the telegraph
stations tho extent OF Underground wire in the large
cities being therefore small compared with the
overhead lines In London the South Eastern, Lon.
oon. Chatham and Dover and London, Brighton and
south Coast railways. all terminate at the Cannon
street station within third OF milo Of the General
Telegraph Office ST Martins le Grand and the wires
station The short distance thence to the Central
Telegraph station is traversed by underground lines
The same applies to the Paddinglon station and Ens-
ton square. The system Of underground lines IN
England at the present time embraces abvut 5000
miles OF wire out OF total mileage OF telegraph line
OF about 100000.
ENGLISH UxpEacKouYD LINES.
Mr.. Prescott gives the following description OF tho
construction OF the underground lines IN England
"The conductors usually employed for underground
lines consist OF No Is copper wire. covered with
guttnpcrcha TO the gauge Of No In order 10 Keep
TO which would It TO crack and decay and thus
destroy the insulation, Is tnrrcd aud then covered
OF tar through which which tho gutlapercha and
taped wire crawh is composed Of one quart OF lin
see oil to two gallons OF Stockholm tar and applied
warm. The wires when thus prepared cut into
lengths of 400 yards and many required to be
laid in tube made into loose cable ana tied
gethcr with tape distances six feet apart When
the wires drawn into the tubes the tapes
moved and the wires permitted to lay loosely IN tho
pipes The tubes into which the wires are drawn ar6
cast iron socket pipes OF two three and -four inches
diameter the size employed depending upon tho num-
bcr OF wires TO be lad down. tho twoinch pipe holding
twenty ve wres tho three inch seventy wires and the
Our-nch 120 wires. The pipes laid aown under the
nagstones Of tho sidewalks the CUTTERS
age depth OF twenty inches, aud the joints are hled
with lead. Oolong drawing flush boxes made OF
iron, 80 inches long by IL inches wide and II deep,
with lids formed OF an iron iraDe, into which
piece OF 1agsonc Is xcd nro placed undcr the side
walk the curbing at distance OF ms yards in tho
CITY OF London and 100 yards in other parts OF London.
Tho pipes enter these boxes through curved aperture
near the bottom, which open. As the pipes are laid
down an iron wire OF No. gauge IS strung through
them to draw tho cable IN With. When the wires are
10 DO laid down they are tied into loose
cables above described IN lengths Of 400 yards each
and brought to the middle Of section OF 400 yards OF
tubing One end Of the cable IS then attached At the
flush box to tho iron WIRE extending through the Pipe
In one direction and the othcr end OF the cable TO
similar wire extending through the pipe in tho oppo
site direction The cable is then drawn through both
sections at the same tme--a distance Of 400 yards
the greatest distance that part OF tho cable has TO
be drawn in tho tube being 200 yards The wires are
numbered at each 400 yards and the boxes arranged
that the joints and numbers always in the box.
The wircs may DO replaced in the pipes or repairs or
other purposes any time without inicrruptng con-
nection or disturbing the pipes When section Is
found to be defective and to require removal cable OF
wires Of the required length IS brought TO box near
the defective wire and inserted In loop between 1t
and the next and the defective piece Is drawn
out of the pipe tho piece is drawn in Extra wires
are always pro;ided when are drawn IN, SO
that removal is not required until several wires have
lacd IL is Impossible TO draw out o portion OF
the wires without injuring the coating and thereby
destroying the insulation Hence when renewal
becomes necessary oil the wires In the section
placed The pipes arc wcl cleaned nnd tarred inside
while hot, in order to prevent rust which causes the
wires 70 adhere so strongly to the iron rs to become
di1lcut to detach them. The cost OF laying down
cast iron socket ppe for underground wires
IN London is about 81 per yard or 81, 700 per mile
This includes the cost Of the pipe and jointing with
lead the taking up OF the pavement, putting the pipe
In place and repaving The cost per wire for drawing
in tno pipes depends somewhat upon the number Of
ting sixty wires ia pipe including jointing and all
other incidental work, Is $3.50 per mile. Tue cost Of
conducting wiro Tor underground lines consisting OF
copper wire OF No Is gauge covered with guta percha
to No. gauge, tapcd and tarrcd is SS5 per mile The
total cost per mile ior sixty underground wires is
about 81, ,000 or about III per mile OF wire.
'Snce the English telcgraphs have gone into tho
hands CT the government new underground line has
been laid down between Liverpool and Manchester,
consisting OF fourteen conductors, laid in iron and
stoncware pipes The length OF the line is about
thirtysx miles, and about twothirds is laid down in
stonewarc pipes and one third In pipes. he iron
pipes thrceinch cast iron in nine feet lengths. with
sockets for joints. The stoneware pipes thrcc
inches in diameter and three feet In length. The
depths at which tho pipes laid are foot or the
iron and two iect Tor the stoncwarr The iron pipes
previous TO laying down cleaned out with heavy
iron chain for tho removal OF any sharp points or
burra Tho stoncware pipes wcrc cleaned with rod
with Two pieces Of iron ike halt pipes kept apart by
spring The pipes when laid down were carefully
adjusted as to III closely, and the joints then
made. AS each pipe was laid in It's place No 16 gal
ynnized iron wire was threaded through Tho JOINTS
IN tho pipes made by first rammng
yarn TO prevent tho molten lead from running into tho
pipe. clay mou1 was then formed around the pipe
and the lead run in Tho quantity OF lead used Tor
this purpose was about one pound per joint. In the
stoneware pipes the joints made with Sourbrdge
clay, which, while making good Joint Tor the proven
OF dirt entering the pipe, is sufficiently porous to
allow water to percolato through It, At the distance
of every two hundred yards IN straight lines were
placed flush boxes into which the pipes were led
project within, the space around them being pro-
tcced prevent dirt from falling into the box.
The mouth Of each pipe also stopped to prevent
the dirt from getting into the DtpC Tho cables
divided into 4Q and 404 yard lengths and the whole
work was subdvidcd TO 400 yard lengths the boxes at
these intervals being termed JOINT boxes and the inter
mediate drawing in boxes Tho joint boxes placed
the distance of 400 yards apart. The intermediate
or drawing in boxes IN straight line were placed at
200 yards IRON ajoint box, half way between the
joint boxes but where there curves in
across these intermediate increased as tho
occasion required Inc cable used IN this event
sisted CT copper wire OF No Is gauge $50 lbs. per
mile covered with eutta pcrcha TO No. 4G lbs. per
mlle aud were manufactured IN the same way that
ocean cables are made as regards the core being
mating with two OF guta pcrcha, and having total
weight OF s5 lbs. per mile
1he underground cables now in use in Paris are COM
posed uniformly OF conductors, each consisting
OF strand OF seven copper wires insulated with several
thckncsses OF gutia percha- They arc placed In the
sewers IN the catacombs, and in iron tubes under tue
strccts The cables which are carried through the
sewers are enclosed in lead tubes TO prevent the
developed there destroying the guta percha In tue
catacombs, which free from any development OF
gas the seven insulated wires simply wrapped with
tape serving prepared of sulphao OF copper. Eight
such cables, supporting zinc trough inches
deep inches wide are carried along the sides
OF the passages. The temperature of the catacombs
seldom varies from hityfour degrees Fahrenheit; tho
atmosphere Is damp the floor beng generally only a
few feet above the level ofthc wcs and water is al
ways precolatng through the rock. For the lines
underneath the streets tubes empoved TO pro-
tcct them against mechanical injury. white they also
prevent the circulation OF the reard the detcr
Grafton cf tue gutta pcrcha by oxidation and by the
escape OF the essential OIL whose presence seems
necessary TO preserve its elastic condition These
tubes like those used for gas they cast iron
In lengths OF about eight feet their diameter being
proportioncd TO the number wires which they have
to contain. They are planted trench n yard dcep
The separate lengths are connected with lead FONTS
and at distances o from fifty ljO yards tube IS in
serted OF large diameter which sdcs over tho ends of
two ncighboring ones, so that by pushing back the
Ines can at any time bc got Mt for repairs These
also used Tor drawing the cables through the tubes
THIS Is done In lengths of 400 yards in London the
cable beng first we'll covered with powdered tale TO
reduce the friction against the sides the tubes.