Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1889-05-12
The Essence That Hangs About Telegraph
Wires Made TO Garry Messages.

The Essence That Hangs About Telegraph
Wires Made to Garry Messages.
New York Sun.l
An Englishman, @. Langdon-Davis,
claims to have perfected an instrument,
called the phonopore, by which the "induc-
tion current" on electric wires is utilized to
carry messages, and the capacity of tele-
graph or telephone line thereby increased.
The induction current is the thing that
makes the buzzing and cracking noise in
the telephone and that slings fragments Of
what is passing on other wires into the mid.
die Of what you are trying to tell some one
else over the line. 1t is sort of faint
essence of electricity that hangs about every
electric wire, and is affected similarly, but
in lesser degree, by everything that affects
the current ON the wires. Its strength varies
with the intensity of the main current and
the condition of the weather. but there is
always enough of it to be a nuisance on long
wires and when delicate work is desired.
The induction from telegraph wire is so
strong that it will overcome entirely the
weaker current of telephone wire near it
on the same pole and make it impossible to
transmit Ineligible sounds over the latter
when the former is in use at the same time
The English invention claims to harness
this faint current to regular instruments and
make it work independently of and simulta-
neously with the main current on the wire
The main feature of the invention appears
to be the use at the receiving instrument of
two wires insulated from each other, but
each attached at one end to the main wire.
The regular current cannot communicate
through these wires, because they are in
LOFT oh h,,S L.
current exists between them, in spite of the
insulation, and any impulse communicated
to the induction current at any station on
the line is faithfully reflected by the induc-
tion current over these two wires at the re-
ceiving end. By delicate adjustments SIM
liar to those used in the duplexing and
quRdruplexing ordinary wires, the impulses
of the induction current are kept separate
from those of the regular current, and will
carry separate message from that passing
on the main wire.
1t is claimed that it will be possible by
the use of the phonopore to double the ca
pacity of an ordinary Telegraph wire work
ing singlY, by simply attaching the new in
strument at each end. A duplex wire can
be made quadruplex in moment by the
same operation, and quadrupfex wire sex
tuplex or octuplex. The phonopore may be
hitched on at way stations instead of at the
end of the line, and works as well, and in
perfect independence of the main current.
1t can be put on at place where there is no
regular instrument. Experiments now be-
ing made over English railroad lines are
said to prove conclusively that the inven-
tion is capable of easy and profitable use in
connection with existing telegraph systems.
1t does not appear, however, that this new
English invention is more than an inn
provement and perfection Of the system of
telegraphing from moving trains, which has
been in use in this country on the Lehich
Valley Railroad for some time, and is said
to have proved to be practicable and use
full. In both systems the induction from
regular telegraph lines is used.