New-York tribune., 1875-11-26
UNDERGROUND WIRES.
THE WESTERN UNION COMPANYs EXPERI-
MENI.


RE ENCOUNTKRED-EXPERiENCE IN RUROPE-
THE BEST sUBTERRANEAN SYSTEM IN LONDON.
Active preparations are making by the West
ern Union Telegraph Company for laying the pneumatic
tubes and suberanean wires between the main ONCE OF
the company and the Broadst Office permission ior Wch
was granted by the Common Council last week Already
the pipes and valves been completed and the engine
is under way. II the weather proves favorable, IA he
intention TO have tubes in working order by jan L.
1875 There will be two tubes each OF which VIII con-
sst Of lead pipe having pa inches inside diameter IN
eased in iron pipe having an interior diameter Oh
inches the latter being designed as protection 10 'ho
lead The cylinders of the airpumps for comlressng
and exhausttng the air IN the tubes have diameter
n, 3b inches Messages from the main office Will be us
patched by Of compressed air through one ol INC
tubes while those TO he returned to the central once
Will PASS through the other tube by exhaustng inc a
the engine pumps and valves all being placed IN the cen
office. The carriers are made of gutapereha COW
cred with felt cloth the forward end being sufficiently
enlarged to the tube and thus prevent the passage OF
Air In either direction beyond the carrier ltisesmaed
that the time occupied in sending message from tue
central Office TO the Office In Broads viii be about %
seconds while the arrangement viii be such tha' one
carrier n necessary can Immediately follow another
George b. Prescott the electrician OF the Company,
stated recently 20 a reporter of THE TRIBUNE that the
plan Of laying the wires viii not dlcT materially from
that pres in in Lordon, although some rev I'M
provements Will he introduced. THE system in Lon
dom said Mr. Prescott, Consists In Insulating small
copper wires with laa-percha, which are then drawn
through 3nch iron tubes, laid under the sidewalks Az
the end of every 30 yards In the city there are D"K
called flush boxes where the wires can be reached IN
ease trouble while often as every 400 Yaros tue
wires are jOined Gutts-percha is the only substance
which has been found available for insulating under
ground wires, and this becomes soft at about
IOO0 Fahrenheit, while If exposed TO the atmos-
phere to street gas, many chemical SUD
stances, stagnant water, it becomes rotten ana
nnat for use The difficulties, however, ais-
ing from defects IN insulation il is found are very sats
facto.ily by the use of wires covered WIN
ruta-pereha and then eneased in iron tubes but the
difficulties arising static induction are fundamental
in their character, and cannot be obviated by any I'M
proyeme ls or notifications Of suberranean cOnsruc-
ton All telegraph wires, without regard to their posi-
on are thus affected but wires placed under ground or
water are affected 80 times much those which pass
through the air. the amount Of the static charge In aerial
wires being inversey proportional ~ the distance OF he
yre from the earth. The amount OF the statlc
charge in all telegraph wires, whether stretched
I'm the cir buried in the ground, Is
unconditional ALSO the length of the wire, and con-
sequenty underground wire of half nle TO mile III
length may he worked without any serious inconVen-
ience from the presence OF the static charge, we one {"
greater length may give rise to the most serious uou
bic The pecuiarty of Manhattan Island is such tbat II
we were forced TO put all our wires under grouhd
throughout the city, each line would have length OF at
least miles buried under the earth, thus giving
capacity equal to 800 miles of wire stretched ON poles
o. IN working wire extending under ground from this
city 10 Buffalo Pittsburgh should he compelled u
operate line having a static capacity of about LOCO
miles This length Of line II would be impossible TO work
at ANYTHING like the present rate OF speed, the rate OF
,peed on long telegraph lines being nversely proper
toual 10 the amount Of the static charge thereon
EXPERIMENTS EUROPE.
Mr. Prescott also stated that he seat TO Europe
about three years ago for the purpose of examining the
oneson AZ 10 how far ground teegrapby pac
ticabIe which he did by visiting England France, ana
Germany There are in England he said, ""bout
10000 miles of telegraph wire, OF which only 3'Ooo
niles are under ground, while in France and Germany
the proportion is much less than in England over 20
years ago underground wires were eonstuctedn Prussia
extensively, but they were all abandoned, and oher
wires placed upon poles for two first, because
n was found impossible to keep them properly In
,uatcd owing 10 the deterioration or the
gu,tapercha, and, secondly, because the appa-
ra;us could not be successfully worked IN c0nnee-
ton with underground wires on account OF the re
,n wTs " we're insulated The same was trne
gland and Ali the subeTanean lines laid III
placed by and poles. In some of the cities how
ever and particularly in London, Paris ana Bern, some
o: the wires have been and are stu carried under
ground IN Paris large amount OF money has been ex,
pended in underground experiments Dnt no plan proved
Napoleon the wires were insulated with gnt1apeicha
and then made into cables somewhat resembling the SUB
marine telegraph cables only that they contained
larger number Of conducting wires to each cable Inc
II
or where did not exist, th.y were Passed
through the catacOmbs The wires oweveI 40 not run
the various railroads. from winch they are cseenttaSu
al central station. When the message is ready Tor de
livery sent out through pneumatic tube of when
extensive system III Paris mt so leuclenyls
the Telegraph service that private company soe ul'
ago got up yelOoipedc express . -. -,
The English underground system IL the beSt1n the
world and London better adapted for underground
telegraph lines any OF American cities Tor the
that there not 20 many changes ana Improve
ments constantly making All the railroads nave sta
tons centrally situated in london most OF the roads com
ing into the OF the city Tie Great sonthtasteIn
hallway, for instance, has station az CahnoBs';' d.
which is only One-thr Of mile from the General Post
Office where the headquarters of Tire Engisa telegraph
lines situated Now ese te apn NiIes al ar p,cu @
on poles ana follow the lines of the railroads mo INC
stations where they hrst pass under eroIhu running ~
eubeuanean lines only from tne r;iOau terll 10 me
central telegraph station Hence, tue quantity OF uhd1r-
ground wire IN London ~ compai,iNey very 81 si' ' ~
addition, u may ne stated tht IN an IiisU U1 eS etdS
there are certain large distributing teeStaph olhces
tIr cy-Of which there 100 10 J00-and every wire
frOm each OF these distributing Offices 10 the several
there arr several wires running Ia tie same station they
insulated on poles which are iesened 10 me topS %
there are IN London 800 private lines, run
ning TO ali psrts OF me aty dIo, aSg use
There single rod Of wire working all these nsu
nens under ground, the wires an Dlns carried
are made into nale cable, which is suspended on hx
attached 10 the roofs OF the houses ~ i NOT IO
able that these instruments could be worked on undeI
fe in tneIand witch constructed an underground line
between London and Liverpool the cable cOntalnlng
10 wires. This company sent over to the
iHiteG states for two House printing telegraph
Instruments, as experiment. with view OF adopting
the systcm the whole line II proved successi dd
athogh they took the precau0n secure the assist
refused record Slc signal Alter SlA Wcth5
tTal lie Company adopted English needle sysem,
bur in less than years alter the line was but It's III
sulatOn became 20 much impaired that the company
Was obliged to up and replace considerable portion
Of the cable one wire after another still continued To
fan until there were only hNo OF The Ten lhat would
work at all After ths, others failed eectlos OF the
ndegeround line were abandoned and wires placed on