IMPROVEMENTS IN TELEPHONE WIRES OR CABLES
Year: 1880

page_text: :
LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
TELEPHONE WIRES OR CABLES." A communication from abroad by Frédéric
Allen Gower, of Paris, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 24th February 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN TELEPHONE WIRES OR CABLES." A communi-
cation from abroad by Frédéric Allen Gower, of Paris, in the Republic of France.
This Invention has for its object obviating the difficulties which result from the
proximity of the lines of wires employed for telephonic purposes, so as to prevent
the liability of induction which interferes with or interrupts the communication.
In carrying out this Invention, in order to effect this object, a cable is employed
composed of a conducting wire surrounded with an insulating material, which is
covered externally by a wire wound in helical coils, serving for the communication
with earth. The insulating material may consist of cotton steeped in paraffine, or
any other suitable material. By means of the arrangement herein before described
an insulating covering is provided for the protection of the central conducting wire,
and a wire wound in the form of a helix is provided for the protection of the
covering, and serves at the same time as a wire for the return to earth, being in
communication with the latter through tho brackets, containing tube, or other
support.
This external metallic helix also performs a third function, vis, obviating the
parallelism of the currents of induction between one cable and another, it having
been ascertained that the induction takes place more particularly between parallel
wires, whilst helical wires on the contrary prevent, or at least diminish, this
derivation of the telephonic currents.
In addition to the advantages, hereinbefore referred to, obtained by the use of
this system of telephonic wires or cables, all liability is obviated to danger from fire
or injury from friction, or by rats, and facility is afforded for laying the cables and
keeping them in order, whilst their power of resistance is greatly augmented.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 19th
August 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN TELEPHONE WIRES OR CABLES." A communi-
cation from abroad by Frederic Allen Gower, of Paris, in the Republic of France.
The said Invention, relating to improvements in telephone wires or cables, has
for its object obiating the difficulties or defects in telephonic communication which
are due to the proximity to each other of a number of different lines of wire, and
the consequent inductive action which takes place affecting, and, in some cases,
suspending the communication.
These difficulties or defects are peculiar to telephonic lines, or do not operate to
a prejudicial extent in telegraph lines.
In the case of telegraph lines the number of wires in juxta position is always
small, since, as the wires are employed for establishing communication between :
very distant stations, they are not in proximity to each other, except in the vicinity
of the central stations to which the wires converge from points at a great distance
apart. Wires for telephonic communication, on the other hand, being provided
for the use of private individuals, merchants, stock brokers, bankers, newspaper
correspondents, and the like, situate either in the same town or within a very a
limited radins, it results that a considerable number of wires are commonly
employed running in the same or nearly the same direction. Hence arises that
inductive action which is so prejudicial to telephonic communication, but which
either does not take place in telegraph lines, or is only present to an inappreciable
extent by reason of the less sensitive or delicate character of the receiving
instrument employed in telographs.
Numerous attempts have already been made to overcome the serious disadvantage
before referred to in telephonic communication, but the means employed are either
too costly, difficult, or delicate to ensure their adoption. By means of the present
Invention, however, the desired result is obtained by a peculiar construction of 3
wires or cables which are comparatively inexpensive, may be produced with
facility, and are not liable to be put out of order.
In carrying out the said Invention each cable is composed of a conducting wire
surrounded with an insulating material, which is covered externally by a wire
wound in helical coils, serving for the communication with earth. The insulating 3
covering, which may consist of cotton steeped in paraffine, or any other suitable
material, is provided for the protection of the central conducting wire, and the wire
wound in the form of a belix is provided for the protection of the covering, and
serves at the same time as a wire for the return to earth, being in communication
with the latter through the brackets, containing tube, or other support.
4
This external metallic belix also performs a third function, videlicet, obviating the
parallelism of the currents of induction between one cable and another, it having
been ascertained that the induction takes place more particularly between parallel
wires, whilst helical wires on the contrary prevent, or at least diminish, this
derivation of the telephonic current, by means of which it is sometimes possible 4
to hear a message which is being transmitted through an adjacent wire, whereas
the necessity for preserving the privacy of the telephonic communications is
indispensable to the success of an enterprise of this description.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to 5
the several Figures on the annexed Sheets of Drawings, the same letters of reference
indicating corresponding parts in all the corresponding Figures.
Figure 1 of the accompanying Drawings is an elevation partly in section of a

page_text: cable constructed according to the said Invention, the view being drawn to an
enlarged scale, and Figure 2 is a corresponding transverse section of the same.
Figures 3 and 4 represent a mode of arranging the cables in a sewer.
A wire a serving to establish communication between two telephones is
surrounded by a tube b of insulating material, which may consist of cotton soaked
in paraffin, and a wire c acting as a return wire and communicating with the earth
is wound round the whole in close helical coils; this wire neutralises the effects of
the induced currents from adjacent wires by providing a metallic covering connected
with the earth on the exterior of the cable.
The conducting medium thus obtained is protected from the attacks of rats,
whose teeth are unable to lay hold of the protecting coils enclosing the cotton
impregnated with paraffin or other insulating material, and all danger from fire is
obviated, even when the most combustible insulating materials are employed, as
the flame is immediately extinguished by the action of the wires conducting the
heat, on the principle of a Davy lamp, and distributing it over a large surface in
lieu of leaving it concentrated.
The conducting wire is also protected from external injury, from friction, and
other like causes, being enclosed in a strong and flexible metallic covering.
Wires or cables constructed as hereinbefore described may be arranged in sewers
or other subterraneous passages, as represented in Figures 3 and 4; in these
Figures a number of such wires or cables A are represented as carried on supports or
brackets S attached in a convenient position to the sides of the sewers or other
conduits.
In whatever position the conducting wires are placed the communications are
never liable to interruption, and wires may be added or removed with the greatest
facility.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is,-
Constructing telephone wires or cables with a wire wound in helical coils upon
insulating material covering the conducting wire, substantially as and for the
purpose herein before described.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Twelfth day of August, One thousand
eight hundred and eighty.
J. HENRY JOHNSON. (L.S.)