IMPROVEMENTS IN INSULATING AND PROTECTING TELEGRAPHIC CONDUCTORS
Year: 1859

page_text: LETTERS PATENT to William Hooper, of Mitcham, in the County of
Surry, India-rubber Manufacturer, for the Invention of "IMPROVEMENTS
IN INSULATING AND PROTECTING TELEGRAPHIC CONDUCTORS."
Sealed the 7th October 1859, and dated the 8th April 1859.
PROVISIONAL SPECIFICATION left by the said William Hooper at the
Office of the Commissioners of Patents, with his Petition, on the
8th April 1859.
I, WILLIAM HOOPER, of Mitcham, in the County of Surry, India-rubber
Manufacturer, do hereby declare the nature of the said Invention for "In-
IN INSULATING AND PROTECTING TELEGRAPHIC CONDUCTORS," to be
as follows:-
This Invention has for its object improvements in insulating and protecting
telegraphic conductors. For this purpose I first coat the conductor with
india-rubber, as has before been done, and I afterwards apply over the first
coat another coat consisting of india-rubber combined with sulphur (or a
substance having a similar action) in the proportions suitable for producing,
when heated, vulcanized, or hard, or semi-hard india-rubber. The two coats
above mentioned I separate the one from the other by a layer of a material
which will prevent the action of the sulphur of the outer coating on the inuer
coat when the heat necessary to change the outer coat is applied. In order
thus to separate the two coats, I usually employ a layer of tin metal; or a
thicker layer of metal may be applied to withstand any tensile strain to which
the protected telegraphic conductor may be subjected. This thicker layer of
metal may be applied in the form of wire woven or bound on, or otherwise.

page_text: The composition for the outer coat may contain other matters besides india-
rubber and sulphur, as is well understood by manufacturers of hard and semi-
hard india-rubber. The india-rubber for the inner coat may also be mixed
with other substances, such, for example, as shellac or gutta percha; or in
some cases the inner coat may be composed of gutta percha uncombined with
india-rubber.
In the manner above described I am able to manufacture telegraphic con-
ductors, protected externally with vulcanized, or hard, or semi-hard india-
rubber, and having within this external coat another coat of insulating material
.containing no sulphur, in which joints can readily be made, and which will
not act injuriously on the conductor.
In some cases I apply over the first coat and the separating material two
coats of vulcanized, or hard, or semi-hard india-rubber, and I then prefer
that the middle coat should be made softer and more flexible than the
outer coat.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Hooper in the Great Seal Patent Office on the
8th October 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HOOPER, of Mitcham, in the County of Surrey, India-rubber Manufacturer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, hearing date the Eighth day of April, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Hooper, Her special licence that I, the said William
Hooper, my executors, administrators, and assigns, or such others as I,
the said William Hooper, 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 "INPROVEMENTS IN INSULATING AND PROTECTING TELEGRAPHIC CONDUCTORS,"
upon the condition (amongst others) that I, the said William Hooper,
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

page_text: 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 Oflice
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said William Hooper, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention has for its object improvements in insulating and protecting
telegraphic conductors. For this purpose I first coat the conductor with.
india-rubber, as has before been done, and I afterwards apply over the first
coat another coat consisting of india-rubber combined with sulphur (or a
substance having a similar action) in the proportions suitable for producing,
when heated, vulcanized, or hard, or semi-hard india-rubber. The two coats
above mentioned I separate the one from the other by a layer of a material
which will prevent the action of the sulphur of the outer coating on the inner
coat when the heat necessary to change the outer coat is applied. In order
thus to separate the two coats, I usually employ a layer of thin metal; or a
thicker layer of metal may be applied to withstand any tensile strain to which
the protected telegraphic conductor may be subjected. This thicker layer of
metal may be applied in the form of wire woven or bound on, or otherwise.
The composition for the outer coat may contain other matters besides india-
rubber and sulphur, as is well understood by manufacturers of hard and semi-
hard india-rubber. The india-rubber for the inner coat may also be mixed
with other substances, such, for example, as shellac or gutta percha; or in
some cases the inner coat may be composed of gutta perchia uncombined with
india-rubber.
In the manner above described I am able to manufacture telegraphic con-
ductors protected externally with vulcanized, or hard, or semi-hard india-
rubber, and having within this external coat another coat of insulating
material containing no sulphur, in which joints can readily be made, and
which will not act injuriously on the conductor.
In some cases I apply over the first coat and the separating material two
coats of vulcanized, or hard, or semi-hard india-rubber, and I then prefer
that the middle coat should be made softer and more flexible than the
outer coat.
Having thus stated the nature of my said Invention, I will proceed more
ully to describe the manner of performing the same.
When the metal conductors are to be insulated with india-rubber, I first

page_text: coat each wire, (when single wires are used as conductors,) or other form of
metal conductor, with india-rubber uncombined with sulphur, either by lap-
ping strips or bands of india-rubber spirally around or otherwise, so as to
completely cover the wires, the edges of the sheet india-rubber overlapping as
has heretofore been done; or the india-rubber, rendered suitably plastic, may
be applied to wires or metal conductors by means of suitable rollers, as has
before been proposed to be done. And I would state, that wires or other
anetal conductors may, when preferred, be wound round with cotton, silk, or
other fibrous yarn before applying the insulating coating of india-rubber, all
which are well understood, and the wires or other metal conductors may be
coated with tin or other preservative metal before applying the insulating
coating of india-rubber.
The first part of my Invention consists in producing on such insulating
coating of india-rubber a further coating or coatings, consisting of vulcanized
india-rubber, or a coating of india-rubber rendered into what is known as a
hard compound of india-rubber, there being interposed between the inner
insulating coating of india-rubber and the protecting or outer coating of
vulcanized india-rubber or hard compound of india-rubber a layer or coating
of metal or other isolating or separating material, with a view to prevent as
much as may be any action of the sulphur in the outer coating acting upon
the inner insulating coating of india-rubber which is not combined with
sulphur. Having applied the inner insulating coating of india-rubber, the
same is then to be covered with thin sheet metal, such as tinfoil or other
metal foil, by lapping narrow strips thereof around the inner insulating coating
of india-rubber; or the sheet metal may be otherwise applied; or the isolating
or separating coasing may be of paper, or woven fabric, or of yarns of cotton
or other fibrous material wound round or otherwise applied; or the separation
may consist of a suitable varnish, not prejudicially acted on by the heat of
the process of vulcanizing or converting the india-rubber of the outer coating,
in which case I prefer collodion and a solution of shellac combined in equal
proportions, which is spread over the inner coating, and dried before applying
the outer coating, so as to cover the insulating covering of india-rubber.
Over this isolating or separating coating the other or outer coating of india-
rubber is applied by any convenient means; but this coating is to be suitably
combined with sulphur or matters which contain or which will, as is well
understood, give off sulphur, or produce the well-known effect of vulcanizing
the india-rubber, or of producing the hard compounds of india-rubber when
heat is applied thereto; and when such outer coating has been applied, the
same is to be subjected to heat, as is well understood, in order to convert the

page_text: india-rubber and sulphur into vulcanized india-rubber, or into a hardened
compound of india-rubber. The effects of thus applying heat to produce the
réquisite change in respect to the outer coating of india-rubber will be to join
and combine the edges of such outer coating, and also to join and combine
the overlapping edges of the inner insulating coating, and render each coating
as if it had been originally laid on without joint. I would remark, that it is
not essential that the india-rubber of the inner insulating coating should be
pure and uncombined with gutta percha or material other than sulphur, but
it is preferred that india-rubber alone should be used for such inner coating.
Wires or other metal conductors thus insulated may be used in this state in
the earth or under water, but I prefer generally to apply to the outer surface
of the vulcanized outer coating of india-rubber a coating of asphalte varnish,
or other water-repelling varnish; and when greater strength and further
protection are required, the coated conductors above described may-be-coated.
with wires or strands of wires laid thereon, or with yarns or cords of hemp
or other material laid, wound, or braided thereon as has heretofore been
practised in making cables or ropes for electric telegraphic purposes. It
should, however, be remarked, that when using wires or strands of wires, or
yarns or strands of hemp or other fibrous material, it is preferred to apply
the same before subjecting the india-rubber compound to heat.
The second part of my Invention consists in the production of a vulcanized
or converted india-rubber coating on wire or other metal conductors which
are coated with gutta percha, whether applied directly to the metal conductors
or on to conductors which have previously been coated witli tin or other pro-
tecting metal. In thus using converted india-rubber as an outer coating to
an inner coating of gutta percha, it is desirable so to conduct the process of
changing the india-rubber that bigh temperatures shall not get to the gutta
percha; this may be prevented by applying a thicker coating of isolating or
separating matter (than is necessary in the previous case) of non-conducting
material, such as cotton, hemp, or other fibrous material; but I prefer, when the
inner insulating coating is of gutta percha, to use the converting process known
as Parkes's, which consists in immersing india-rubber into a bath composed of
forty parts of bisulphuret of carbon, to which is added one part of chloride of
sulphur or hypochloride of sulphur prepared as neutral as possible, the same
being well mixed in an earthenware or other suitable vessel for a short time, till
the degree of change required is produced; and afterwards I prefer, when dry,
to pass the coated conductor slowly through a bath of melted sulphur. When
this process is to be employed in carrying out this part of my Invention, the
india-rubber used for the outer coating is not when first applied combined with

page_text: sulphur or sulphur compounds, but india-rubber only, and the same is to be
laid on in such manner that the edges of the sheet india-rubber arc cemented
or joined by heat, or the india-rubber is to be applied by grooved rollers, so as
not to have any scams or joins, all which are separately well known.
Having now described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I make no claim to any
parts of the processes herein described separately; but what I claim is,—
First, the combining an outer coating of vulcanized india-rubber, or of a hard
sulphur compound of india-rubber, with an inner coating of india-rubber on
metal telegraphic conductors, and separating the inner and outer coatings, as
herein described.
And, secondly, I claim the combining an outer coating of vulcanized or
converted india-rubber with an inner coating of gutta percha, as hercin
described.
In witness whereof, I, the said William Hooper have hereunto set my
hand and seal, this Seventh day of October, in the year of our Lord
One thousand eight hundred and fifty-nine.