AN IMPROVEMENT IN TREATING ARTICLES OF GUTTA PERCHA MADE OR FORMED IN DIES OR MOULDS, ALSO CERTAIN ARTICLES OF GUTTA PERCHA MADE BY EXPRESSING THROUGH DIES, AND ALSO ARTICLES OF GUTTA PERCHA MADE BY PRESSING ROLLERS
Year: 1858

page_text: LETTERS PATENT to John Macintosh, of North Bank, Regent's Park,
for the Invention of "AN IMPROVEMENT IN TREATING ARTICLES OF GUTTA
PERCHA MADE OR FORMED IN DIES OR MOULDS, ALSO CERTAIN ARTICLES OF
GUTTA PERCHA MADE BY EXPRESSING THROUGH DIES, AND ALSO ARTICLES OF
GUTTA PERCHA MADE BY PRESSING ROLLERS."
Sealed the 9th August 1858, and dated the 12th February 1858.
PROVISIONAL SPECIFICATION left by the said John Macintosh at the
Office of the Commissioners of Patents, with his Petition,., on the
12th February 1858.
I, JOHN MACINTOSH, of North Bank, Regent's Park, do hereby declare the
nature of the Invention for "AN IMPROVEMENT IN TREATING ARTICLES OF GUTTA
PERCHA MADE OR FORMED IN DIES OR MOULDS, ALSO CERTAIN ARTICLES OF GUTTA
PERCHA MADE BY EXPRESSING THROUGH DIES, AND ALSO ARTICLES OF GUTTA PERCHA
MADE BY PRESSING ROLLERS," to be as follows:-
This Invention has for its object an improvement in treating articles of
gutta percha made or formed in dies or moulds, also certain articles of gutta
percha made by expressing through dies, and also articles of gutta percha
made by pressing rollers.
In the Provisional Specification of a Patent, bearing date the 14th day of
November 1857, I described, amongst other things, the subjecting electric
telegraph wires, coated with gutta percha, to the action of sulphuric acid and

page_text: then to water, by which treatment the coatings are rendered less liable to
injury from tropical and like temperatures. In pursuing my experiments I
have found that other articles of gutta percha (with or without foreign
matters) made or formed in moulds or dies, also tubes and solid articles, not
containing wires, made by expression through dies, and also sheets and other
articles made by pressing rollers, subjected to the action of sulphuric acid over
their exterior or interior or both their exterior and interior surfaces, and then
to water, are made capable of bearing considerable temperatures as compared
with the temperatures which will act injuriously thereon when manufactured
in the ordinary manner without such after treatment. And although I prefer
that the articles so treated should be wholly composed of gutta percha, still
the presence of some foreign matters does not prevent the beneficial effects
on the gutta percha articles.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Macintosh in the Great Seal Patent Office on the
12th August 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MACINTOSH, of North Bank, Regent's Park, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of February, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-first year
of Her reign, did; for Herself, Her heirs and successors, give and grant unto
me, the said John Macintosh, Her special licence that I, the said John
Macintosh, my executors, administrators, and assigns, or such others as I,
the said John Macintosh, 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 "AN
IMPROVEMENT IN TREATING ARTICLES OF GUTTA PERCHA MADE OR FORMED IN DIES
OR MOULDS, ALSO CERTAIN ARTICLES OF GUTTA PERCHA MADE BY EXPRESSING
THROUGH DIES, AND ALSO ARTICLES OF GUTTA PERCHA MADE BY PRESSING ROLLERS,"
upon the condition (amongst others) that I, the said John Macintosh, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and ascer-
tain the nature of the said Invention, and in what manner the same was to

page_text: 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 Macintosh, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object an improvement in treating articles of
gutta percha made or formed in dies or moulds, also certain articles of gutta
percha made by expressing through dies, and also articles of gutta percha
made by pressing rollers. In the Provisional Specification of a Patent bearing
date the 14th day of November 1857, I described, amongst other things, the
subjecting electric telegraph wires, coated with gutta percha, to the action of
sulphuric acid and then to water, by which treatment the coatings are
rendered less liable to injury from tropical and like temperatures. In pur-
suing my experiments I have found that other articles of gutta percha (with
or without foreign matters) made or formed in moulds or dies, also tubes and
solid articles not containing wires made by expression through dies, and also
sheets and other articles made by pressing rollers subjected to the action of
sulphuric acid over their exterior or interior or both their exterior and interior
surfaces, and then to water, are made capable of bearing considerable tem-
peratures as compared with the temperatures which will act injuriously
thereon when manufactured in the ordinary manner without such after treat-
ment. And although I prefer that the articles so treated should be wholly
composed of gutta percha, still the presence of some foreign matters does not
prevent the beneficial effects on the gutta percha articles.
In carrying my Invention into effect I prefer to proceed in the following
manner: The article to be treated whether it be of gutta percha alone or
gutta percha mixed with foreign matter, such as india-rubber or bitumen,
and whether it be formed in moulds or dies, or is a tube or a solid article
(not containing wires) made by expression through dies, or is a sheet or
other article, made by pressing rollers, is plunged into a bath of sulphuric
acid, that which I prefer to employ being the concentrated acid of commerce,
and is retained in the bath for a period varying from a few seconds to several
minutes, it is then removed from the bath and immersed in cold water, in
which it is well washed, so as entirely to remove the acid, and the process is
then complete. The duration of the acid immersion depends on the nature
of the article under treatment. If it be made wholly of gutta percha, and
that of good quality, and if the object of the process be only to give a surface

page_text: to the article, a few seconds of immersion is found to be sufficient; but if the
appearance of the surface is not so much an object as the hardening the
material to a considerable depth, the period of immersion may be increased
to minutes even when the article is of pure gutta percha, and when the
gutta percha is mixed with foreign matter the process takes a longer time to
produce a corresponding amount of action than when the article is made of
pure gutta percha. If in any case the immersion be continued for too long
a time it results in a cracking of the surface of the article to an injurious
extent.
I would remark that by the employment of the process above described
I am enabled to render blocks made from a mixture of inferior india-rubber
with a small proportion of gutta percha suitable for erasing pencil marks.
In witness whereof, I, the said John Macintosh, have hereunto set my
hand and seal, this Twelfth day of August, in the year of our Lord
One thousand eight hundred and fifty-eight.
Witness,
GEO. PITT.
JOHN MACINTOSH. (L.S.)