Iм- PROVEMENTS IN THE CONSTRUCTION OF SUBMARINE TELEGRAPH CABLES, AND IN THE MODE OF INSULATING THE CONDUCTORS USED THERE WITH, APPLICABLE TO OTHER TELEGRAPHIC PURPOSES
Year: 1875

page_text: LETTERS PATENT to William Thomas Henley, of Plaistow, in the
County of Essex, Telegraphic Engineer, for the Invention of "Iм-
PROVEMENTS IN THE CONSTRUCTION OF SUBMARINE TELEGRAPH CABLES, AND
IN THE MODE OF INSULATING THE CONDUCTORS USED THERE WITH, APPLICABLE
TO OTHER TELEGRAPHIC PURPOSES."
k
Sealed the 19th May 1876, and dated the 26th November 1875.
PROVISIONAL SPECIFICATION left by the said William Thomas
Henley at the Office of the Commissioners of Patents, with his
Petition, on the 26th November 1875.
I, WILLIAM THOMAS HENLEY, of Plaistow, in the County of Essex,
Telegraphic Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF SUBMARINE TELEGRAPH CABLES,
AND IN THE MODE OF INSULATING THE CONDUCTORS USED THEREWITH, APPLICABLE TO
OTHER TELEGRAPHIC PURPOSES," to be as follows :-
My improvements consist, firstly, in constructing submarine telegraph
cables so as to combine lightness with strength, and at the same time to

page_text: latter from forcing their way between the cords, the object being that
the wires shall compress the strands of fibrous material, and keep them
firm in their places, and that the wires shall only sink so far between
them, as shown in the Figures in the Drawing. As many wires as cords
be employed, but for a light cable I prefer only half the number,
so that a wire lays in the interstice between every second cord or strand.
may
Cables have been made in which the core after being served with
yarn has been covered with a layer of alternate wires and strings of
same size, or with wire strands and strings laid on together in long
spirals. In a cable thus constructed the only strength is on the wires,
as no strain can come on the strings until the wires break, but in one
constructed according to these improvements both wires and cords take
the strain. The latter will stretch more than the wires, but as the
cords stretch they allow the wires to compress them, and come nearer
the core, and thus the spirals of wire elongate in the same ratio as the
strands or cords, the compression of the latter and the webbing pre-
venting the wires from ever forcing between the cords down to the
core.
The cords of Manilla, or other strong fibrous material, have great
strength, and the introduction of five wires weighing six hundred-
weight per mile altogether increases the breaking strain of the cable by
nearly three tons. After the wires are laid on I serve the whole with a
coat of compound webbing, and afterwards pass it through hot marino
gluc, or other similar compound, but as this outside coating of webbing
and compound has been in use before on cables I lay no claim to
this. A cable thus constructed will bear a much greater strain
either in water or air than any other form of the same weight.
My improvements in the method of insulating the conductors used in
submarine telegraph cables, and for other telegraph purposes, consists in
'curing" the india-rubber covered conductor in ozokerit, paraffin, or
other similar hydrocarbons instead of high-pressure steam, as at present
used.
"
Instead of using an iron cylindrical vessel with cover, in which the
india-rubber is coiled for the purpose of being vulcanized or cured,"
as technically termed, and which is then charged with high-pressure

page_text: steam, I use a double vessel or steam jacketed cylinder, the outer vessel
or jacket only being charged with steam, the inner, in which the core is
placed, being charged with hot ozokerit, paraffin, or other similar sub-
stance, which is still further heated by the steam in the jacket. The
paraffin may be subjected to pressure in the "cure" by means of a force
pump, but the vapour of the paraffine in the " cure will generally exert
sufficient pressure. I prefer using more sulphur in the outer coating
of india-rubber compound of the core than when cured in the ordinary
way.
"
The advantage of thus treating the india-rubber core will be shown
by the following statement of facts :-Vulcanized india-rubber core, as
at present manufactured, slowly absorbs water, and thus loses its insu-
lating properties, and when used when it is alternately wet and dry this
absorption takes place very rapidly, and the core in the course of two or
three months becomes quite useless. This has been found to be the
case invariably when laid under ground, and in the parts of shore end
cables when subject to the ebb and flow of the tide, and a gutta percha
covered wire becomes deteriorated when placed under ground, not
through absorbing moisture, but from becoming dry or oxidising. No.
material has as yet been found suitable for subterranean lines of
telegraph, but by these improvements india-rubber core can be made
which shall remain perfect for any length of time, whether used for land
or sea lines.
Another way I propose to carry out this improvement and to effect
the same result is by curing the core in the usual way by high-pressure
steam, then completely dry all the moisture out of it by any ordinary
means, or place it in the steam jacketed cylinder for that purpose, and
when quite dried force the ozokerit or paraffin into the vessel with a
force pump when in a melted state, and the jacket charged with
steam.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Thomas Henley in the Great Seal Patent
Office on the 26th May 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
THOMAS HENLEY, of Plaistow, in the County of Essex, Telegraphic
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth 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 suc-
cessors, give and grant unto me, the said William Thomas Henley,
Her special licence, that I, the said William Thomas Henley, my
executors, administrators, and assigns, or such others as I, the said
William Thomas Henley, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein 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 "IMPROVEMENTS IN THE CONSTRUCTION OF SUBMARINE
TELEGRAPH CABLES, AND IN THE MODE OF INSULATING THE CONDUCTORS USED
THEREWITH APPLICABLE TO OTHER TELEGRAPHIC PURPOSES,"
" upon the con-
dition (amongst others) that I, the said William Thomas Henley,
my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, 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 Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Thomas Henley, 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, reference being had to the
accompanying Drawings and to the letters of reference marked thereon,
that is to say :-
-
My improvements consist, firstly, in constructing submarine telegraph
cables so as to combine lightness with strength, and at the same time

page_text: the latter from forcing their way between the cords, the object being
that the wires & shall compress the strands 6 of fibrous material, and
keep them firm in their places, and that the wires shall only sink so far
between them, as shewn in the Figures on the Drawing. As many
wires as cords may be employed, but for a light cable I prefer only half
the number, so that a wire lies in the interstice between every second
cord or strand.
Cables have been made in which the core after being served with
yarn has been covered with a layer of alternate wires and strings of
same size, or with wire strands and strings laid on together in long
spirals. In a cable thus constructed the only strength is in the wires,
as no strain can come on the strings until the wires break, but in one
constructed according to these improvements both wires and cords take
the strain. The latter will stretch more than the wires, but as the cords
stretch they allow the wires to compress them, and come nearer the
core, and thus the spirals of wire elongate in the same ratio as the
strands or cords, the compression of the latter and the webbing pre-
venting the wires from ever forcing between the cords down to the
core.
The cords of Manilla or other strong fibrous material have great
strength, and the introduction of fine wires weighing six hundred-
weight per mile altogether increases the breaking strain of the cable by
nearly three tons. After the wires are laid on I serve the whole with a
coat of compound webbing e, and afterwards pass it through hot marine
glue, or other similar compound, but as this outside coating of webbing
and compound has been in use before on cables I lay no claim to
this. A cable thus constructed will bear a much greater strain either
in water or air than any other form of the same weight.
My improvements in the method of insulating the conducters used in
submarine telegraph cables, and for other telegraph purposes, consist in
curing the india-rubber covered conducter in ozokerit, paraffine, or other
similar hydrocarbons instead of high-pressure steam, as at present
used.
Instead of using a cylindrical iron vessel with cover, in which the
india-rubber is coiled for the purpose of being vulcanized or "cured," as
technically termed, and which is then charged with high-pressure steam,
I use a double vessel or steam jacketed cylinder, the outer vessel or

page_text: jacket only being charged with steam, the inner, in which the core is
placed, being charged with hot ozokerit, paraffine, or other similar sub-
stance, which is still further heated by the steam in the jacket. The
paraffine may be subjected to pressure in the cure by means of a force
pump, but the vapour of the paraffine in the cure will generally exert
sufficient pressure. I prefer using more sulphur in the outer coating
of india-rubber compound of the core than when cured in the ordinary
way.
The advantage of thus treating the india-rubber core will be shewn
by the following statement of facts:-Vulcanized india-rubber core, as
at present manufactured, slowly absorbs water, and thus loses its insu-
lating properties; and when used where it is alternately wet and dry
this absorption takes place very rapidly, and the core in the course of
two or three months becomes quite useless. This has been found to be
the case invariably when laid under ground, and in the parts of shore
end cables where subject to the ebb and flow of the tide, and a gutta
percha covered wire becomes deteriorated when placed under ground,
not through absorbing moisture, but from becoming dry or oxidising.
No material has as yet been found suitable for subterranean lines of
telegraph, but by these improvements india-rubber core can be made
which shall remain perfect for any length of time, whether used for land
or sea lines.
Another way I propose to carry out this improvement and to effect the
same result is by curing the core in the usual way by high-pressure
steam, then completely dry all the moisture out of it by any ordinary
means, or place it in the steam jacketed cylinder for that purpose, and
when quite dried force the ozokerit or paraffine into the vessel with a
force pump when in a melted state, and the jacket charged with
steam.
Having thus described my Invention, and some modes of carrying the
same into effect, I declare that I claim,-
Firstly. The construction of submarine telegraph cables by the com-
bination of wires and of strands or cords of strong fibrous material,
substantially in the manner herein-before described and illustrated in
the Drawings annexed.

page_text: telegraph conductors for submarine cables, and other purposes, all sub-
stantially as herein-before described.
In witness whereof, I, the said William Thomas Henley, have
hcreunto set my hand and seal, this Twentieth day of May, in
the year of our Lord One thousand eight hundred and seventy-
six.