Savannah morning news. [volume] (Savannah) 1868-1887, 1882-07-20
TELEpHONING UNDERGROUND.
Interesting Experiment on q Syste mn
OF Subterranean Wires.
Netg York Times. 18Th.

Ne,g York Times. 18Th.
A saries OF tests OF a subterranean tele-
| phone was undertaken yesterday afternoon
| in the little booth of the Western Union
| Telegraph Company on the dock at Com.
/ munfpaW. It is now four years since, In
| Philadelphia, a mile OF subterranean cable
was laid from a point near the old Penn
| sylvsnia Railroad depot IN the direction or
/ GraY's dock on the river. The expert
ment was made under patent obtained by
| Mr.. David Brooks, OF Philadelphia, who
had Just invented a new mode OF insula
| ton for telegraph or telephone wires.
the main specification OF which consists In
the use Of a-flaid hydro carbon or gas. As
| laid down between Newark and Jersey City,
the Brooks system is very simple. The
length of the pipe In which the wires are
fnclosed is nine and half miles. The pip.
| NAV be of any convenient diameter, and Is
smoothed internally bv means of a sand
bath. The wires (No. l6 copper are wound
with cotton or j1Je, and pulled through the
pipe by means of powerful capstan. The
| length that may be pulled through at any
one time, and the largest distance between
the joints. consequently, is about 5000 feet,
or little more than half mile. When the
wires have been pulled through the pipe
and the latter has been laid In place, the
remaining space (not occupied by the con-
ductors) Is filled With paraffine oil, which op-
crates as an insulatOr excludes all moisture,
aud perfectly performs its office, Ol the ton
OF Bergen Hill is tank which contains seven
barrels Of oil and communicates with the
pipe containing the telephone wires The
pipe from Newark to Jersey City possesses
a capacity of about ten barrels. There Is
thus the constant pressure of the seven bar
rels OF fifty gallons each on the pipe In
which the wires are inclosed, and thus an
alteration in volume occasioned by the
4
contraction in winter Is compensated for,
and no water can possibly enter the recepta-
Gle. 1t costs about SO per wire per mile for
tube containing 100 wires to lay such ca
BILE, whereas it costs no less than $50 per
mile to put up telegraph wires in the ordi-
nary way.
Tue success of the experiment in Phila-
delphia In 1878 led to the sale of the patent
to the Western Union Company for tele-
graph purposes at price of $3.50, ,000 and
the inventor went to Europe Immediately
after to introduce it there. Sections were
laid in Belgium, France and England, and
"1re Sminently successful
r-, - .nS nnl meantime, an attempt was made to
tha e w. JoVie from Newark to Jersey City by
miles ~ wires ,ho mon Company. and some five
Lllles VI wires Were put down In the salt
meadows, but the j JeTse,, o. - "a Sa..si soiO
authorities refused peTm3ss anu - SsosLh
the streets, and the project hS5 .. " uiseuLO s.
returned from Europe be hit ~
idea of availing himself of the rigs 'ne
way of the railway between Newark aHS
Jersey City. He thus obtained access to
both, aud connected the Western Union Of
fees in Newark with the station on the dock
at Communipaw. The cable is not laid ia
the best manner, but the experiments were
no less successful than If the inventor had
superintended every rod of the work. The
material used for Insulation is the second
distillation of petroleum, or rather the resi-
due that is left-a thick, heavy oil, good for
lubricating purp0ses-atter the burning fluid
has been distilled off. This residue con-
tsins traces of soda and sulphuric acid,
which would corrode the wires IL left In the
oil, and this fact renders a second distills-
tion necessary, which slightly increases the
cost per gallon. Iu the experiments yes
terday afternoon the two points it was pro-
posed to determine were the amount of in
reference by induction and the general
practicahility of the system. 1t is a ia
miliar fact to the reader that when he
puts his ear to the loud transmitter of the
telephone to listen to person at the other
end, voices not intended for his benefit, and
really passing on other wires, are passed
over TO the conductor that he is using. This
faint electrical reverberation is styled induc-
ton, and how to get rid of it has been one
OF the problems of telephone engineering.
There is also frying sound that is due to
induction, and there are other difficulties
that are familiar only to experts. Combined
together, these difficulties have hitherto ma
terially interfered with transmission at long
distances, and 1t was claimed that they
could not be overcome If subterranean wires
were used.
The experiments yesterday were witnessed
by few persons only, among whom were
Mr.. Vail and Mr.. Jaques, Manager and
Electrician of the Bell Telephone Company
of Boston; Mr.. j. w. Dyer, a Philadelphia
Electrician of high repute; Mr.. Chinook,
Electrician of the Metropolitan Company of
this city, and Mr.. Davis, its President; Mr..
Robinson, of Philadelphia; Mr.. Brooks the
inventor, who took no material part In the
tests, and few other gentlemen. In order
that experts of the best skill might be at
both ends OF the cable, Mr.. Chinook went
to Newark and operated the Newark
end, while Mr.. Dyer and Mr..
Jsques operated the instruments at
Communipaw. These wires had been
connected until circuit one hundred and
fifty miles In length was established, and
this was first tested. There were some en-
barrassing circumstances, one of them
being the fact that the Western Union svs-
TEN, using dynamo equal to one hundred
and elghIy-hVe volts at this end and sixty-
cell Colland battery at the other, was in
constant operation parallel with the tele-
phone wires. The first tests were made with
wires, Mr.. Dyer talking with the
operative at the Newark end while Mr..
Jaques listened for induction interference.
The voice of Mr.. Chinook could be family
heard as result of induction, but Mr..
Jaques pronounced It not sufficient to
interfere with the practical work.
ing OF lines. One wire after another
was then tested, with substantialIv
the same result, both with the wires
and not grounded, in. order to
measure the induction as a separate factor.
The next experiment was to connect several
series of wires into metallic circuits and to
institute the same series OF tests as to in
duction. No. l and No. were first en-
pioyed In this manner, and there was abso-
lutely no sound brought to the ear nv tbe
second transmitter. When No. 9 and No
10 were similarly connected and the tests
were applied the voice at the other end was
heard in faint, far off manner, and only an
occasional word could be distinguished
The same was the case with circuit COM
posed Of No. % and No. "a. The experI-