IMPROVED APPLIANCES AND MEANS FOR SIGNALLING THROUGH PROVISIONAL SPECIFICATION THROUGH LONG SUBMARINE TELEGRAPH CABLES AND OTHER CIRCUITS
Year: 1875

page_text: LETTERS PATENT to Desmond Gerald Fitz-Gerald, of Loughborough
Road North, Brixton, in the County of Surrey, Electrician, for the
Invention of "IMPROVED APPLIANCES AND MEANS FOR SIGNALLING THROUGH
PROVISIONAL SPECIFICATION left by the said Desmond Gerald Fitz-
Gerald at the Office of the Commissioners of Patents, with his
Petition, on the 2nd November 1875.
I, DESMOND GERALD FITZ-GERALD, of Loughborough Road North,
Brixton, in the County of Surrey, Electrician, do hereby declare the
nature of the said Invention for "IMPROVED APPLIANCES AND MEANS FOR
SIGNALLING THROUGH LONG SUBMARINE TELEGRAPH CABLES AND OTHER CIRCUITS,"
to be as follows :—
The object of my Invention is to increase the speed of signalling in
long submarine telegraph cables, or to reduce the cost of such cables by
effecting a very considerable diminution in the weights of conducting

page_text: and insulating materials now necessary to obtain a given rate of speed
in signalling.
My Invention consists in the construction and use of two forms of
current induction apparatus, which when intended to be submerged with
the cable constitute submarine "translators," containing no adjust-
ments or other parts liable to derangement or deterioration after sub-
mersion, and preferably forming portion of the cable itself. By
means of such apparatus the cable is divided into two or more distinct
circuits, the speed of signalling being thus increased in.accordance with
what is known as the "law of the inverse square of the length."
"
In one form of the apparatus the translator consists essentially of a
modified induction coil, in which the " "primary" and "secondary'
wires are generally similar, and are coiled side by side. These wires
have each one terminal in contact with "earth," the other terminals
being respectively connected to the two sections of cable conductor,
between which the apparatus intervenes. The carth contacts are
effected by means of a ring or cylinder or of two separate rings or
cylinders of platinum or other non-oxidizable conductor, surrounding
the apparatus and connected with one terminal of each coil, as afore-
said. The wires constituting the coil are preferably insulated with
gutta percha or other waterproof insulating material throughout their
whole length. They may be made to surround a core of soft iron,
which is advantageously constituted by the sheathing wires of the cable
or a portion of them, or the sheathing may surround the double coil of
wire and enclose the apparatus.
In the other form of the apparatus (by which the effect of "magnetic
retardation is perhaps more completely obviated) the translator
consists essentially of an electro-magnet, through which the cable
conductor is connected to carth at any selected point or points. The
soft iron core of the magnet may be constituted by the sheathing wire
of the cable, upon which is coiled any requisite length of conducting
wire, which may be insuted throughout its length with gutta percha
or other waterproof insulating material; or the coil of wire surrounding
a separate soft iron core or otherwise may be enclosed within the
sheathing, and may be insulated throughout its length by a fibrous non-
conductor, and externally by a waterproof dielectric. One end of this
insulated coil of wire is connected to earth by means of a ring or

page_text: oylinder of platinum or other non-oxidizable conductor, and the other
end is connected with the cable conductor, as aforesaid at the point
where the cable is to be divided into separate sections.
When the cable can be divided on dry land I connect the two sections
by means of a simplified form of the same apparatus consisting either
of two wires of equal length coiled side by side around a core of soft
iron, and connected one terminal to an earth plate or earth plates, and
the other terminals respectively to the two sections of cable, or else of an
electro-magnet (which may be single or compound), one terminal of
which is connected with both sections of cable, the other terminal being
in contact with an earth plate.
The Invention may also be in certain cases applicable to land
circuits.
A succession of induced currents in the same direction may if
necessary be obtained by an increase of the battery power at the
sending station, effected by means of a suitable key or transmitting
apparatus.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Desmond Gerald Fitz-Gerald in the Great Scal
Patent Office on the 2nd May 1876.
TO ÁLL TO WHOM THESE PRESENTS SHALL COME, I, DESMOND
GERALD FITZ-GERALD, of Loughborough Road North, Brixton, in the
County of Surrey, Electrician, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of November, in the
year of our Lord One thousand eight hundred and seventy-five, in
the thirty-ninth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Desmond Gerald Fitz-
Gerald, Her special licence that I, the said Desmond Gerald Fitz-
Gerald, my executors, administrators, and assigns, or such others
as I, the said Desmond Gerald · Fitz-Gerald, my executors, admini-
strators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein

page_text: expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVED APPLIANCES AND
MEANS FOR SIGNALLING THROUGH LONG SUBMARINE TELEGRAPH CABLES AND OTHER
CIRCUITS," upon the condition (amongst others) that I, the said Desmond
Gerald Fitz-Gerald, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and scals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Scal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Desmond Gerald Fitz-Gerald,
do hereby declare the nature of my said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
:—
The object of my Invention is to increase the speed of signalling in
long submarine telegraph cables, or to reduce the cost of such cables by
effecting a very considerable diminution in the weights of conducting
and insulating materials now necessary to obtain a given rate of speed
in signalling.
My Invention consists in the construction and use of two forms of
current induction apparatus, which when intended to be submerged
with the cable constituto submarine "translators," containing no ad-
justments or other parts liable to derangement or deterioration after
submersion, and preferably forming portion of the cable itself. By
means of such apparatus the cable is divided into two or more distinct
circuits, the speed of signalling being thus increased in accordance with
what is known as "the law of the inverse square of the length."
"
"
In one form of the apparatus the translator consists essentially of a
modified induction coil, in which the " primary" and secondary'
wires are generally similar, and are coiled side by side. These wires
have each one terminal in contact with " earth," the other terminals
being respectively connected to the two sections of cable conductor,
between which the apparatus intervenes. The earth contacts are
effected by means of a ring or cylinder, or of two separate rings or
cylinders, of platinum or other non-oxidizable conductor, surrounding
the apparatus and connected with one terminal of cach coil, as afore-

page_text: said. The wires constituting the coil are preferably insulated with
gutta percha or other waterproof insulating material throughout their
whole length. They may be made to surround a core of soft iron,
which is advantageously constituted by the sheathing wires of the cable,
or a portion of them; or the shoathing may surround the double coil of
wire and enclose the apparatus.
"
In the other form of the apparatus (by which the effect of “magnetic
retardation is perhaps more completely obviated) the translator consists
essentially of an electro-magnet, through which the cable conductor is
connected to earth at any selected point or points. The soft iron core
of the magnet may be constituted by the sheathing wire of the cable,
upon which is coiled any requisite length of conducting wire, which
may be insulated throughout its lenth with gutta percha or other
waterproof insulating material; or the coil of wire surrounding a
separate soft iron core or otherwise may be enclosed within the
sheathing, and may be insulated throughout its length by a fibrous con-
ductor, and externally by a waterproof dielectric. One end of this in-
sulated coil of wire is connected to earth by means of a ring or cylinder
of platinum or other non-oxidizable conductor, and the other end is
connected with the cable conductor, as aforesaid, at the point where the
cable is to be divided into separate sections.
When the cable can be divided on dry land I connect the two sections
by means of a simplified form of the same apparatus, consisting of either
two wires of equal length, coiled side by side around a core of soft iron,
and connected one terminal to an earth plate or earth plates, and the
other terminals respectively to the two sections of cable, or else of an
electro-magnet (which may be single or compound), one terminal of
which is connected with both sections of cable, the other terminal being
in contact with an earth plate.
The Invention may also be in certain cases applicable to land
circuits.
As an example of the construction of the first form of the apparatus,
as herein-before described, forming portion of the cable itself, I will take
the case of a long submarine cable in which the core (formed of a copper
conductor insulated with gutta percha or india-rubber) is wrapped in a
'serving" of hemp fibre, and is enclosed within a sheathing of iron
wires, each of which is also wrapped in hemp. In that portion or
**

page_text: length, or in those portions or lengths, of the cable where the apparatus
is to divide the line into sections, it is preferable that the sheathing
wires should be of the softest iron. I take one of these lengths of the
cable, and by torsion in the direction opposite to that of the "lay" of
the sheathing wires I uncoil the latter, and then remove from the
cable a certain length of the core, together with its hemp "serving,"
corresponding to the required length of the duplex coil of wire to
be introduced in the cable at this point. I remove also the hemp
"serving" from the iron sheathing wires, and between two of the latter,
at each of the ends (which I will call A and B) of the length of cable
from which the core has been removed, I pass or lead out externally the
two free extremities of the cable core, with any suitable precautions that
may be necessary to guard them against injury by compression. The
sheathing wires are then twisted together, and constitute the core of soft
iron upon which the helical duplex coil of wire is to be wound. I then
take the two insulated wires (p and 8) of which the duplex helical coil
is to be formed, and I solder or attach one of them (p) to the cable corc
at A, and the other (s) to the inner surface of a cylinder or ring of
platinum or other non-oxidizable metal or conductor which surrounds
the cable at this point. These two insulated wires are then coiled
together in as many layers as may be necessary upon the above-
mentioned core of soft iron. The end of the wire (1) is connected to
the inner surface of a second ring or cylinder of platinum, and the end
of the wire (8) to the cable core at the extremity B. The two rings or
cylinders of platinum are insulated from the sheathing wires of the
cable, and are imbedded in insulating material, so that their outer
surfaces only are in contact with earth." The wires and 8 are
preferably of much smaller sectional area than the cable conductor, and
should be of such diameter and length that when a momentary current
from the battery employed for signalling is sent through p from the
signalling station in the direction of A, the two superposed currents in
opposite directions induced in 8 produce a distinct "reversal" or
"constant zero signal at the station in the direction of B, leaving the
line free of charge or nearly so.
"
66
It will be understood that the wires and 。 are rospectivaly (6 animoun"}

page_text: tensile strength also is the same by reason of the iron sheathing wires
enclosed within it.
"
As an example of the construction of the second form of apparatus
herein before described I uncoil the sheathing wires and remove their
hemp "serving" over a certain length, which I will express as from A
to B. At A I connect to the cable conductor a wire, preferably of
smaller dimensions than this conductor, and insulated throughout its
length, preferably with a waterproof insulating material. The sheathing
wires, which at this point should be of very soft iron, constitute when
they are again twisted or laid together the iron core upon which the
wire is coiled. The free end of this wire is soldered or otherwise
attached to the inner surface of a ring or cylinder of platinum or other
non-oxidizable metal or conductor, which surrounds the cable at the
point B. The coiled wire should preferably be of such dimensions that
whilst on the one hand its resistance and the "magnetic inertia” of the
electro-magnet which it constitutes (in conjunction with the soft iron
core) are sufficient to prevent too great a "derivation or loss of the
current from the signalling battery employed at either station, on the
other hand the current induced in it on breaking the battery circuit aids
in the production of the signal before the charge of the cable can flow
to earth through the apparatus. By a due adjustment of these
dimensions the elementary signal (obtained by a single depression of the
signalling key) should be produced by three automatically superposed
currents, viz., one directly from the signalling battery; a second in the
opposite direction, induced by the passage of the battery current through
the coil; and a third, which is the "extra current" induced in the coil
by breaking the battery circuit. By such adjustment the signalling
current may be "curbed" to any required extent. The "magnetic
retardation" of the current through the coil should be made in effect to
insulate the signalling current, whilst the "derivation" to carth facili-
tates the "discharge" of the cable. The whole apparatus, with tho
exception of the outer surface of the platinum ring or cylinder, is
preferably encased externally by insulating material, such as india-
rubber or gutta percba, in addition to that which coats the wire in the

page_text: coil. The diameter of the apparatus need not be greater than that of
the cable, whilst its tensile strength may be preserved equal.
In constructing the form of apparatus intended to be used on land,
between two cables or otherwise, I prefer to arrange in series upon a
board a number of electro-magnets, having a high amount of magnetic
inertia, i.c., rendering potential a considerable quantity of electrical
energy. To augment this inertia the coils of the magnets may be sur-
rounded by hollow cylinders of soft iron, and the magnetic circuits arc
closed by armatures uniting the poles of the magnets.
"
The coils may be wound with two wires, so as to constitute an appa-
ratus for electro-dynamic induction, analogous to what is herein-before
described as "the first form of the apparatus ; or with one wire, so as
to constitute a compound electro-magnet, through which two sections of
cable or other line may be connected to earth. In the former case I
prefer to cut a longitudial groove in the soft iron
cores of the clectro-
magnets, and to slit longitudinally the soft iron cylinders which may
surround the coils. The connections to be made in either case are
herein-before described.
Having now particularly described and ascertained the nature and
object of my said Invention, and in what manner the same is to be per-
formed or carried out in practice, I hereby declare that I claim,—
1. The use, for the purpose of increasing the speed of signalling in
telegraph cables, of a current induction apparatus, preferably forming
portion of the cable itself, and composed of two wires helically coiled
upon a
"core" of iron, and each wire connected at one extremity to
"earth" by means of an electrode of platinum or other non-oxidizable
conductor, and at the other extremity to one of the two sections of
cable, between which the apparatus intervenes, substantially as herein-
before described.
2. I claim the use, for the same purpose, of an apparatus preferably
forming portion of the cable itself, and composed of a single wire
helically coiled upon a core of iron, and connected at one extremity to
the cable conductor, and at the other extremity to earth by means of
an electrode of platinum or other non-oxidizable conductor, substantially
as herein-before described.

page_text: 3. I claim the use of the above apparatus in a simplified form, sub-
stantially as herein-before described, on dry land, between two sections
of submarine cable, or two sections of underground or aërial line.
In witness whereof, I, the said Desmond Gerald Fitz-Gerald,
have hereunto set my hand and seal, this First day of May,
in the year of our Lord One thousand eight hundred and
seventy-six.
DESMOND G. FITZ-GERALD. (L.S.)
Witness,
T. MORGAN,
Secretary,
Inventors' Patent Right Association, Ld.,
21, Cockspur Street, S.W.