Year: 1894

page_text: Date claimed for Patent under Sect. 103 of Act,
being date of first Foreign Application (in 19th Dec., 1893
United States of America),
Date of Application (in United Kingdom), 13th July, 1894
Complete Specification Left, 13th Apr., 1895-Accepted, 24th May, 1895
United States of America),
Date of Application (in United Kingdom), 13th July, 1894
Complete Specification Left, 13th Apr., 1895-Accepted, 24th May, 1895
PROVISIONAL SPECIFICATION.
I, SILVANUS PHILLIPS THOMPSON of the Technical College, Finsbury, London,
in the County of Middlesex, Doctor of Science, do hereby declare the nature of
this invention to be as follows:-
My invention relates to improvements in submarine electric cables, and more
particularly to means for overcoming the retardation of signals therein.
In my former applications for Letters Patent No. 13064 dated 4 July, 1893,
and No. 15217 dated 9 August, 1893, I have shown, described and claimed
methods and apparatus having this end in view. The present application, however,
differs therefrom in certain important particulars, as will more fully appear
hereafter.
The present application discloses means for adapting my generic invention to
existing types of submarine electric cables, whether the same contain one or two
continuous conductors, and by said means I am enabled to increase their speed of
signalling and also to adapt them for use as telephone circuits.
In the case of a single wire cable, I join on to the conductor at intervals,
compensating branches of the hereinafter described kind, which for telegraphic
purposes may be as much as 200 or even 500 miles apart, and for telephonic
purposes as near together as 20 or 40 miles according to the nature and total
length of the cable.
Each compensating branch consists of a short conductor in metallic connection
with the conductor within the cable and thoroughly insulated with the usual
coatings and sheathings, so as to prevent the admission of water to the main cable
and to the insulated part of the branch, the branch being provided at its extremity
with an exposed metallic terminal, which, being in contact with the water, forms an
"earth-plate," or, in lieu thereof, being connected to the iron sheathing of the cable,
so that the same may act as earth or earth plate.
The brauch possesses resistance and self-induction and is so proportioned that
it forms a leak on the cable of a definite and determined kind, that is to say,
it constitutes a leak differing from an accidental leak in that it possesses a
definite resistance and a definite self-induction, both of which qualities remain
practically constant and are not liable to change by corrosion, as accidental leaks
will do.
In the drawings
Figure 1 is a diagrammatic view of a single-wire cable and branches.
Figure 2 is an enlarged detail showing a method of securing the branches to the

page_text: Figure 4 shows dingrammatically a two-wire cable with alternately arranged
compensating branches.
Figure 5 shows a two-wire cable, each conductor provided with a branch.
Figure 6 is an enlarged detail of one form of exposed terminal.
Figure 7 is an enlarged detail of another form of exposed terminal.
If the compensating branch possesses a high resistance, for example, from 10,000
to 100,000 or more ohns even without any appreciable self-induction, it will
accelerate the speed of signalling. But if it also possesses a co-efficient of self-
induction, say from as little as one milli-henry to as much as one hundred henries,
it will act better as a compensator because such self-induction will not only increase
its apparent resistance, but will also actually in some measure operate favourably as
a negative capacity to counteract the capacity of the cable in the parts within some
miles on both sides of the point where it is attached.
Compensating branches having the desired property will resemble outwardly
portions of ordinary submarine cable, but inwardly differ somewhat.
If an iron
wire is employed in place of the ordinary copper wire, it will have both higher
resistance and a higher self-induction. If a German-silver wire is used, it will
have a higher resistance, but it will not have a higher self-induction unless it is
either coiled around an insulated iron core (which may itself be a stranded bundle
of iron wire, insulated) or is itself rewound with iron outside to increase its self-
induction. A compensating branch five miles long if made of a straight insulated
iron wire one twenty-fifth of an inch in diameter, insulated and overwound with
five layers. of iron wire each about a fortieth of an inch in diameter will have
approximately a resistance of 800 ohms and a self-induction of 300 to 400 .milli-
henry. For rapid signalling it will have a virtual resistance many times greater
than its actual resistance. If the iron wire instead of being straight is lightly
insulated and coiled in a spiral around a well-insulated stranded iron wire as core,
and the whole is then well-insulated externally and enclosed in a proper sheath, it
will serve as a compensating branch of higher resistance.
One end of each such compensating branch will be jointed into the cable,
Figure 2, the insulating material around it being carefully jointed with that
surrounding the cable, and must be continuous with it. The other end will be
connected to a suitable "earth-plate," or similar organ suitable to be immersed in
the sea or to the iron sheathing of the cable. If an iron wire is used as a conductor
in the compensating branch, it may be joined at the end where it is to unite with
the "earth-plate" to a stouter stranded iron-wire, and this again to a still stouter
stranded iron cable, a portion of which may be submerged exposed: or it may
terminate in the iron sheathing of the cable; or an iron plate or ball or shell,
Figures 6 and 7, may be employed, the same being several feet in diameter, giving
also a large surface and a considerable thickness so that the corrosion may be
spread over many years, but in all cases avoiding any exposure to the sea of any
two metals which would set up galvanic corrosion mutually by contact. All such
joints near the sea-end should be preferably made by electric welding. If the last
few feet of the conductor in the compensating branch be constituted of a stranded
platiuum wire jointed on to the iron or German-silver or other wire used in the
branch, the end of the stranded platinum wire may be brought out and welded to a
platinum plate, Figure 6, to serve as an "earth-plate." In all cases, the insulating
covering must be waterproof and be carried right down to the mass of metal which
serves as "earth-plate."
In the cases where the compensating branches are to be applied to an existing
cable containing two insulated conductors, they will be jointed in at one end to a
point on one of the two conductors and at the other end they will be jointed on to
the other conductor, Figure 3, thereby constituting a bridge across from one to the
other conductor. If the two points chosen on the respective conductors are near
together, the compensating branch or bridge must have both high resistance and
high self-induction. But if the two points chosen on the respective conductors are
far apart, then the compensating branch or bridge need not be either of such high

page_text: GE
resistance or self-induction. For example, if the two conductors of the cable are
stranded copper wires each consisting of seven wires, each being one-fortieth of
an inch in diameter, and the compensating branch used as a bridge be ten miles long
consisting of an iron stranded wire made up of three wires each one-fortieth of an
inch in diameter, such compensating branch or bridge should be joined at its ends
to the two conductors respectively at points ten miles apart. In the case of cables
containing two insulated conductors, it is also possible to use compensating branches
not as bridges from wire to wire, but as branches from the cable to the sea, with
earth-plates" as previously described for single-wire cables, but in such case the
compensating branches should be connected to the two conductors alternately:
namely, first from one conductor of the cable to the sea; then at an interval of
ten or twenty or more miles, from the other conductor of the cable to the sea;
then, at another similar interval, from the first conductor to the sea, and so forth.
And in such case also there is no need for the compensating branches so used to
have either a very high resistance or a very high self-induction. For instance, a
branch one mile long consisting of a stranded iron wire made up of three wires, each
one twenty-fifth of an inch in diameter, suitably insulated and connected to a
suitable "earth-plate," may be jointed in, alternately, as described above, at
intervals of ten, twenty, or fifty miles or more. Or two such may be inserted at
fifty or one hundred miles apart, near the middle of a long cable to increase its speed
of signalling. Or again, at the middle of a long two-wire cable, a single bridge f,
Figure 3, may be inserted from wire to wire, its ends being, for example, inserted at
two points twenty miles apart, or a special piece of cable of much smaller length
containing both the bridge wire and the two parallel conductors from to y miy
be inserted in the middle of the two-wire cable.
Referring to the drawings:-
Figure 1 represents the conductor of a single-wire cable, to which are electrically
connected branch wires a, b, c, connected with "earth-plates" E. The branch wires
and conductor A are thoroughly insulated, the "earth-plates" E alone being exposed.
The insulation is in this instance omitted for convenience.
A, in Figure 2, is an enlarged detail illustrating means for lashing the branch
wires to the main cable at a point beyond its junction with said cable in order to
relieve the strain and possible leakage at the joint. A is the branch and A' is a
suitable lashing uniting the main cable and the branch.
Figure 3 shows a two-wire cable A, B, joined by a compensating branch f
extending from one conductor to another, said branch extending over a consider-
able distance and so proportioned as to equalise the electrostatic conditions of the
conductors.
Figure 4 shows diagrammatically a two-wire cable containing conductors A and B,
separately insulated and contained within a single external sheath. In this instance,
branch wires a bextend from the cable A, while similar branches de extend from
the cable B. The branch conductors are the same in structure in this instance as
in Figure 1, but where the cable contains two wires, the branches are taken
alternately from opposite conductors, and although said branches are shown in close
proximity, it must be understood that they are to be placed more or fewer miles
apart, according to circumstances.
Figure 5 illustrates diagrammatically the application of a single pair of
compensating branches g near the middle of a long cable.
Figure 6 shows one form of plate in which the cable a forming the branch is
spread at its end and each strand i thereof soldered or otherwise metallically
connected with an extended exposed plate F, of the same metal as the end of the
branch cable, which is preferably of platinum, for durability. The extremities at
least of the strands of the branch conductor should also be of platinum, care being
taken that the joint between the platinum extremities of the branch conductor and
the remainder thereof, especially if of different material, be securely enclosed within.
waterproof insulating material Í.
A convenient and durable form of terminal for the branch conductors is shown

page_text: in Figure 7, in which the extremity of the branch conductor b is secured to a stem G,
provided with an opening to facilitate handling the same, said exposed stem being
connected with a ball H of the same metal as the stem.
In view of the foregoing description, it will be apparent that the form and
nature of the earth plate or exposed terminal of the branch conductors may be
made in various forms and of various materials. I therefore do not limit
myself to any specific detail in this connection. It is also obvious that the branch
conductors may be arranged in various different ways consistent with the description
thereof.
Dated this 19th day of July 1901
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
Improvements in Electric Cables.
I, SILVANUS PHILLIPS THOMPSON, of the Technical College, Finsbury,
London, in the County of Middlesex, Doctor of Science, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
My invention relates to improvements in submarine electric cables, and more
particularly to means for overcoming the retardation of signals therein.
In my former applications for Letters Patent No. 13064 dated + July, 1893, and
No. 15217 dated 9 August, 1893, I have shown, described and claimed methods
and apparatus having this end in view. The present application, however, differs
therefrom in certain important particulars, as will more fully appear hereafter.
The present application discloses means for adapting my generic invention to
existing types of submarine electric cables, whether the same contain one or two
continuous conductors, and by said means I am enabled to increase their speed of
signalling and also to adapt them for use as telephone circuits.
In the case of a single wire cable, I join on to the conductor at intervals,
compensating branches of the hereinafter described kind, which for telegraphic
purposes may be as much as 200 or even 500 miles apart, and for telephonic
purposes as near together as 20 or 40 miles according to the nature and total
length of the cable.
Each compensating branch consists of a short conductor in metallic connection
with the conductor within the cable and thoroughly insulated with the usual coatings
and sheathings, so as to prevent the admission of water to the main cable and to
the insulated part of the branch, the branch being provided at its extremity with
an exposed metallic terminal, which, being in contact with the water, forms an
"earth-plate," or, in lieu thereof, being connected to the iron sheathing of the
cable, so that the same may act as earth or earth-plate.
it
The branch possesses resistance and self-induction and is so proportioned that it
forms a leak on the cable of a definite and determined kind, that is to say,
constitutes a leak differing from an accidental leak in that it possesses a definite
resistance and a definite self-induction, both of which qualities remain practically
constant and are not liable to change by corrosion, as accidental leaks will do.
In the drawings accompanying the Provisional Specification;
· Figure 1 is a diagrammatic view of a single-wire cable and branches;
Figure 2 is an enlarged detail showing a method of securing the branches to the
cable;
Figure 3 shows diagrammatically a two-wire cable with branches extending
across;
2.

page_text: Figure 4 shows diagrammatically a two-wire cable with alternately arranged
compensating branches;
Figure 5 shows a two-wire cable, each conductor provided with a branch;
Figure 6 is an enlarged detail of one form of exposed terminal; and
Figure 7 is an enlarged detail of another form of exposed terminal.
If the compensating branch possesses a high resistance, for example, from
10,000 to 100,000 or more ohms even without any appreciable self-induction, it
will accelerate the speed of signalling. But if it also possesses a co-efficient of
self-induction, say from as little as one milli-henry to as much as one hundred
henries, it will act better as a compensator because such self-induction will not only
increase its apparent resistance, but will also actually in some measure operate
favourably as a negative capacity to counteract the capacity of the cable in the
parts within some miles on both sides of the point where it is attached.
Compensating branches having the desired property will resemble outwardly
portions of ordinary submarine cable, but inwardly differ somewhat. If an iron
wire is employed in place of the ordinary copper wire, it will have both higher
resistance and a higher self-induction. If a German-silver wire is used, it will
have a higher resistance, but it will not have a higher self-induction unless it is
either coiled around an insulated iron core (which may itself be a stranded bundle
of iron wire, insulated) or is itself rewound with iron outside to increase its self-
induction. A compensating branch five miles long if made of a straight insulated
iron wire one twenty-fifth of an inch in diameter, insulated and overwound with
five layers of iron wire, each about a fortieth of an inch in diameter will have
approximately a resistance of 800 ohms and a self-induction of 300 to 400 milli-
henry. For rapid signalling it will have a virtual resistance many times greater
than its actual resistance. If the iron wire instead of being straight is lightly
insulated and coiled in a spiral around a well-insulated stranded iron wire as core,
and the whole is then well-insulated externally and enclosed in a proper sheath, it
will serve as a compensating branch of higher resistance.
One end of each such compensating branch will be jointed into the cable,
Figure 2, the insulating material around it being carefully jointed with that
surrounding the cable, and must be continuous with it. The other end will be
connected to a suitable "earth-plate," or similar organ suitable to be immersed in
the sea or to the iron sheathing of the cable. If an iron wire is used as a
conductor in the compensating branch, it may be joined at the end where it is to
unite with the "earth-plate" to a stouter stranded iron-wire, and this again to a
still stouter stranded iron cable, a portion of which may be submerged exposed:
or it may terminate in the iron sheathing of the cable; or an iron plate or ball or
shell, Figures 6 and 7, may be employed, the same being several feet in diameter,
giving also a large surface and a considerable thickness, so that the corrosion may
be spread over many years, but in all cases avoiding any exposure to the sea of any
two metals which would set up galvanic corrosion mutually by contact. All such
joints near the sea-end should be preferably made by electric welding. If the last
few feet of the conductor in the compensating branch be constituted of a stranded
platinum wire jointed on to the iron or German-silver or other wire used in the
branch, the end of the stranded platinum wire may be brought out and welded to
a platinum plate, Figure 6, to serve as an "earth-plate." In all cases, the insulating
covering must be waterproof and be carried right down to the mass of metal which
serves as "earth-plate."
In the cases where the compensating branches are to be applied to an existing
cable containing two insulated conductors, they will be jointed in at one end to a
point on one of the two conductors and at the other end they will be jointed on to
the other conductor, Figure 3, thereby constituting a bridge across from one to the
other conductor. If the two points chosen on the respective conductors are near
together, the compensating branch or bridge must have both high resistance and
high self-induction. But if the two points chosen on the respective conductors are
far apart, then the compensating branch or bridge need not be either of such high

page_text: resistance or self-induction. For example, if the two conductors of the cable are
stranded copper wires, each consisting of seven wires, each being one-fortieth of
an inch in diameter, and the compensating branch used as a bridge be ten miles
long consisting of an iron stranded wire made up of three wires, each one-fortieth
of an inch in diameter, such compensating branch or bridge should be joined at
its ends to the two conductors respectively at points ten miles apart. In the
case of cables containing two insulated conductors, it is also possible to use
compensating branches not as bridges from wire to wire, but as branches from the
cable to the sea, with "earth-plates" as previously described for single-wire cables,
but in such case the compensating branches should be connected to the two
conductors alternately namely, first from one conductor of the cable to the sea;
then at an interval of ten or twenty or more miles, from the other conductor of
the cable to the sea; then, at another similar interval, from the first conductor
to the sea, and so forth. And in such case also there is no need for the compensating
branches so used to have either a very high resistance or a very high self-induction.
For instance, a branch one mile long consisting of a stranded iron wire made up
of three wires, each one twenty-fifth of an inch in diameter, suitably insulated and
connected to a suitable "earth-plate," may be jointed in, alternately, as described
above, at intervals of teu, twenty, or fifty miles or more. Or two such may be
inserted at fifty or one hundred miles apart, near the middle of a long cable to
increase its speed of signalling. Or again, at the middle of a long two-wire cable,
single bridge, Figure 3, may be inserted from wire to wire, its ends being, for
example, inserted at two points twenty miles apart, or a special piece of cable of
much smaller length containing both the bridge wire and the two parallel
conductors from a toy may be inserted in the middle of the two-wire cable.
Referring to the drawings aforesaid -
Figure 1 represents the conductor of a single-wire cable, to which are electrically
connected branch wires a, b, c, connected with "earth-plates "E. The branch
wires and conductor A are thoroughly insulated, the "earth-plates" E alone being
exposed. The insulation is in this instance omitted for convenience.
A, in Figure 2, is an enlarged detail illustrating means for lashing the branch
wires to the main cable at a point beyond its junction with said cable in order to
relieve the strain and possible leakage at the joint. A is the branch and A¹ is a
suitable lashing uniting the main cable and the branch.
Figure 3 shows a two-wire cable A, B, joined by a compensating branchf
extending from one conductor to another, said branch extending over a considerable
distance and so proportioned as to equalise the electrostatic conditions of the
conductors.
Figure 4 shows diagrammatically a two-wire cable containing conductors A
and B, separately insulated and contained within a single external sheath. In this
instance, branch wires ab extend from the cable A, while similar branches de
extend from the cable B. The branch conductors are the same in structure in
this instance as in Figure 1, but where the cable contains two wires, the branches
are taken alternately from opposite conductors, and although said branches are
shown in close proximity, it must be understood that they are to be placed more or
fewer miles apart, according to circumstances.
Figure 5 illustrates diagrammatically the application of a single pair of
compensating branches g h near the middle of a long cable.
Figure 6 shows one form of plate in which the cable a forming the branch is
spread at its end and each strand i thereof welded or otherwise metallically connected
with an extended exposed plate F, of the same metal as the end of the branch cable,
which is preferably of platinum, for durability. The extremities at least of the
strands of the brauch conductor should also be of platinum, care being taken that
the joint between the platinum extremities of the branch conductor and the remainder
thereof, especially if of different material, be securely enclosed within waterproof
insulating material I.
A convenient and durable form of terminal for the branch. conductors is shown

page_text: in Figure 7, in which the extremity of the branch conductor b is secured to a
stem G, provided with an opening to facilitate handling the same, said exposed stein
being connected with a ball H of the same metal as the stem.
In view of the foregoing description, it will be apparent that the form and nature
of the earth plate or exposed terminal of the branch conductors may be made
in various forms and of various materials. I therefore do not limit myself to
any specific detail in this connection. It is also obvious that the branch conductors
may be arranged in various different ways consistent with the description thereof.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described method of increasing the speed of signalling of cables
of existing types by providing them at intermediate points with leaks of definite
resistance and self-induction, the same being constituted by conductors insulated
along their length by an external coating of insulating material continuous with
that of the cable.
2. The combination with a single-conductor electric cable of one or more
compensating branches each such branch consisting of an insulated conductor
possessing both resistance and self-induction, jointed in to the cable at some
intermediate point.
3. The combination with an electric cable having two insulated conductors, of
one or more compensating branches, each such branch being jointed in as a bridge
across from one conductor to the other conductor, such branch being surrounded
throughout its entire length with insulating material which is jointed into and
continuous with that of the cable.
4. The combination with an electric cable having two insulated conductors of
an intermediate piece of special cable containing also a bridge wire possessing both
self-induction and high resistance, the insulating material surrounding said bridge
wire being continuous with the insulation surrounding the two insulated
conductors.
5. The combination
or more compensa
one of the conc
from the two conductors.
th an electric cable having two insulated conductors of one
inches, each such branch being jointed on as a leak from
the sea, the branches being taken at intervals alternately
6. The berein described method of applying earth-plates to conductors that are
to be exposed to the action of the sea, consisting of jointing a mass of metal to a
wire of the same metal which is itself enclosed in insulating and waterproof
material down to the said mass.
corder 10 Cun marr cu
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.