IMPROVEMENTS IN INSULATING TELE- GRAPHIC CONDUCTORS, AND IN THE TREATMENT OF GUTTA PERCHA
Year: 1859

page_text: LETTERS PATENT to John Chatterton, of Highbury Terrace, and Wil-
loughby Smith, of Pownall Road, Dalston, both in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN INSULATING TELE-
GRAPHIC CONDUCTORS, AND IN THE TREATMENT OF GUTTA PERCHA."
Sealed the 1st June 1860, and dated the 10th December 1859.
PROVISIONAL SPECIFICATION left by the said John Chatterton and
Willoughby Smith at the Office of the Commissioners of Patents,
with their Petition, on the 10th December 1859.
We, JOHN CHATTERTON, of Highbury Terrace, and WILLOUGHBY SMITH, of
Pownall Road, Dalston, both in the County of Middlesex, do hereby declare
the nature of the Invention for "IMPROVEMENTS IN INSULATING TELEGRAPHIC
CONDUCTORS, AND IN THE TREATMENT OF GUTTA PERCHA," to be as follows:-
This Invention has for its object improvements in insulating telegraphic
conductors, and in the treatment of gutta percha. When telegraphic wires or
conductors are insulated with a covering of gutta percha, it is found that
minute pores in many cases exist in the covering. Now, according to this
Invention, we fill the pores in the gutta percha with an insulating liquid, and
for this purpose the covered wire or conductor is placed in a close vessel, and
the air is exhausted so as to empty the pores as completely as possible, and the
insulating liquid is afterwards forced into them by forcing it under considerable

page_text: pressure into the close vessel. Wires or conductors, with an insulating
covering of india-rubber or other insulating substance, may be similarly treated.
In preparing gutta percha for the purposes of insulation, we in some cases
close the pores by submitting it when in a thin sheet or in a divided state to a
process such as above described. Gutta percha prepared in this manner may
afterwards be applied in the ordinary manner as a covering to telegraphic
wires or conductors.
We also prepare gutta percha for use for other purposes by filling its pores
in the manner above described with a preservative liquid, which will preserve
the gutta percha from decomposition when exposed to air.
In covering telegraphic wires or conductors with several coverings of gutta
percha difficulty is experienced in obtaining a perfect union between the
several coverings. Now, according to this Invention, as the wire or conductor
having received one covering passes to receive an additional covering, it is
drawn through a flame to heat and soften the surface with which the additional
covering is required to unite. A composition is also employed to render the
union between the two coverings more complete, as is now ordinarily practiced.
Also when a covering of gutta percha has been applied to a telegraphic wire
or conductor, in order to cool and harden such covering we cause it to pass
into a tank of an insulating liquid in place of into water, as heretofore.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Chatterton and Willoughby Smith in the Great Seal
Patent Office on the 9th June 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
CHATTERTON, of Highbury Terrace, and WILLOUGHBY SMITH, of Pownall Road,
Dalston, both in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of December, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-third year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said John Chatterton and Willoughby Smith, Her special licence
that we, the said John Chatterton and Willoughby Smith, our executors,
administrators, and assigns, or such others as we, the said John Chatterton
and Willoughby Smith, our 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,

page_text: use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN INSULATING TELEGRAPHIC CONDUCTORS, AND IN THE TREATMENT OF GUTTA
PERCHA," upon the condition (amongst others) that we, the said John Chat-
terton and Willoughby Smith, our executors or administrators, by an
instrument in writing under our or their hands and seals, or under the
hand and seal of one of us or them, 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 John Chatterton, on behalf of myself
and the said Willoughby Smith, do hereby declare the nature of the said
Invention, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement thereof,
that is to say-
This Invention has for its object improvements in insulating telegraphic
conductors, and in the treatment of gutta percha. When telegraphic wires or
conductors are insulated with a covering of gutta percha it is found that
minute pores in many cases exist in the covering, resulting from imperfection
in the process of manufacture. Now, according to this Invention, we fill the
pores in the gutta percha with an insulating liquid, and for this purpose the
covered wire or conductor is placed in a close vessel, and the air is exhausted;
so as to empty the pores as completely as possible, and the insulating liquid is
afterwards forced into them by forcing it under considerable pressure into the
close vessel. Wires or conductors, with an insulating covering of india-rubber.
or other insulating substance, may be similarly treated.
The vessel we employ for containing the covered wire is fitted with a cover;
which is readily removable for the introduction of the wire, and when replaced,
renders the vessel perfectly air-tight. From the vessel a pipe passes to an air-
pump, which is worked until as good a vacuum is obtained as the pump will
produce. A vacuum of twenty-six or twenty-seven inches answers the purpose
well. The pipe connecting the pump and the air-pump is furnished with a
cock, and when the vacuum is complete, the communication between the two
is closed by turning the cock. Above the vessel a tank containing the
insulating fluid is fixed, and is connected with it by a pipe, in which also a
stop-cock is fitted. For the insulating fluid Stockholm tar we believe to be
most suitable, and by preference it is slightly warmed, say to about 70° or 80°
Fahrenheit, the raising the temperature to a degree which might soften the

page_text: gutta percha being carefully avoided. When the vacuum is complete, the tar
is allowed to descend from the tank into the vessel by opening the stop-cock
and care is taken to prevent the tank becoming empty, which would allow air
to enter the vessel. When the vessel contains as much tar as will run into it,
through another pipe connected with the vessel a further quantity of tar is
forced by a pump until a pressure is produced within the vessel. A pressure
of 500 lbs. to the inch answers well. The pipe connecting the pump with the
vessel is fitted with a safety valve, which allows the tar to escape when this
pressure is exceeded. The pressure is maintained for about ten minutes, and
is then taken off and the wire removed. Wire of which the covering is thus
prepared will be found to be better insulated than before it was submitted to
the process.
In preparing gutta percha for the purpose of insulating we in some cases
close the pores or mechanical defects by submitting it when in a thin sheet or
in a divided state to a process such as above described. Gutta percha
prepared in this manner may afterwards be applied in the ordinary manner as
a covering to telegraphic wires or conductors. In applying this process the
gutta percha is taken by preference at that stage of the manufacture when it
has been torn up and washed; it is thoroughly dried before being put into the
If thin sheet
vacuum vessel. The process is conducted as already explained.
gutta percha be taken it will be treated in a similar manner. We, however,
for telegraph wire prefer to treat the covered wire when finished as first
described; and it is usually only when extreme precaution is requisite that we
treat the gutta percha in an unfinished state, and then it is also treated after
it has been applied to the wire.
We also prepare gutta percha for use for other purposes by filling its pores
in the manner above described with a preservative liquid, which will preserve
the gutta percha from decomposition when exposed to air. The insulating
liquid above mentioned is also, we believe, the most suitable for use as a
preservative liquid. The gutta percha may be treated after it has been
washed and dried as above mentioned; it is afterwards manufactured and
made up into any required form. Articles made up of gutta percha so
prepared will be less acted on when exposed to the atmosphere than when
made from gutta percha not so prepared. In many cases it will be more
convenient and better to treat the articles after they are made in place of
treating the gutta percha before its manufacture is complete.
In covering telegraphic wires or conductors with several coverings of gutta
percha, difficulty is experienced in obtaining a perfect union between the
several coverings. Now, according to this Invention, as the wire or conductor

page_text: baving received one covering passes to receive an additional covering it is
drawn through a flame to heat and soften the surface with which the additional
covering is required to unite. A composition is also employed to render the
union between the two coverings more complete, as is now ordinarily practised.
For this purpose we employ ordinary fish-tail gas burners, which we place so
that the covered wire passes through the flames immediately before it enters
the "compound tank," where it receives the coating of composition imme-
diately before having another covering put upon it. We employ two, three,
or four burners, according to the thickness of the covered wire and the speed
at which it is travelling. The number of burners employed is such that the
covered wire after passing through the flames may be just tacky on the surface.
The burners are so mounted that if it be necessary to stop the machine, the
burners may be at once turned away from under it.
Also, according to our Invention, when a covering of gutta percha has been
applied to a telegraphic wire or conductor in order to cool and harden such
covering, we cause it to pass into a tank of an insulating liquid, in place of
into water, as heretofore. The liquid we prefer to employ for this purpose
also is Stockholm tar; this liquid we simply substitute for water, placing it in
a long metal trough contained within the cooling tank of the covering machine
through which a current of water is kept continually running, as heretofore.
In witness whereof, I, the said John Chatterton, have hereunto set
my hand and seal, this Ninth day of June, in the year of our Lord
One thousand eight hundred and sixty.
JOHN CHATTERTON. (L.S.)