AN IMPROVEMENT IN COMBINING GUTTA PERCHA AND ASPHALT OR PITCH
Year: 1856

page_text: LETTERS PATENT to Charles Goodyear, of Leicester Square, in the County
of Middlesex, for the Invention of "AN IMPROVEMENT IN COMBINING GUTTA
PERCHA AND ASPHALT OR PITCH."
Sealed the 13th February 1857, and dated the 30th August 1856.
PROVISIONAL SPECIFICATION left by the said Charles Goodyear at the
Office of the Commissioners of Patents with his Petition on the
30th August 1856.
I, CHARLES GOODYEAR, of Leicester Square, in the County of Middlesex, do
hereby declare the nature of the Invention for "AN IMPROVEMENT IN COMBINING
GUTTA PERCHA AND ASPHALT OR PITCH," to be as follows:-
This Invention has for its object an improvement in combining gutta percha
and asphalt or pitch. Heretofore it has been proposed to combine gutta
percha and asphalt by masticating the same together in like manner to what
gutta percha and india-rubber have been usually masticated, both alone and
in combination. Now, my improvement consists of combining gutta percha
with asphalt or pitch by the aid of hot water, by which the two matters are
softened and made comparatively fluid. And having combined these matters
together, they are, when desired, further combined with sulphur, also with
india-rubber, and also with other matters, and the various compounds thus
produced are, when required, subjected to high temperatures, in order to
produce the change which is consequent on applying high temperatures to
gutta percha or india-rubber, or both, combined with sulphur or matters
giving off sulphur by heat.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Goodyear in the Great Seal Patent Office on the
28th February 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
GOODYEAR, of Leicester Square, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of August, in the year of our Lord One
thousand eight hundred and fifty-six, in the twentieth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Charles Goodyear, Her special licence that I, the said Charles Goodyear, my
executors, administrators, and assigns, or such others as I, the said Charles
Goodyear, 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 COMBINING
GUTTA PERCHA AND ASPHALT OR PITCH," upon the condition (amongst others)
that I, the said Charles Goodyear, 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 Charles Goodyear, 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 following the
statement thereof, that is to say :-
This Invention has for its object an improvement in combining gutta percha
and asphalt or pitch. Heretofore it has been proposed to combine gutta
percha and asphalt by masticating the same together, in like manner to what
gutta percha and india-rubber have been usually masticated, both alone and
in combination. Now, my improvement consists of combining gutta percha
with asphalt or pitch by the aid of hot water, by which the two matters are
softened and made comparatively fluid. And having combined these matters
together, they are, when desired, further combined with sulphur, also with
india-rubber, and also with other matters, and the various compounds thus
produced are, when required, subjected to high temperatures, in order to
produce the change which is consequent on applying high temperatures to

page_text: gutta percha or india-rubber, or both, combined with sulphur or matters giving
off sulphur by heat.
Having thus stated the nature of my said Invention, I will proceed more
fully to describe the manner of performing the same.
Heretofore when combining gutta percha and asphalt or pitch it has been
usual to employ masticating machines, so as by mechanical effort to mix them
in as uniferm a manner as possible, and although heat has been applied to
heat such masticating machines, the heat has not been such to render the
substances into a comparatively fluid state, so that they will run or pour
freely, and I have discovered that it is of great importance when manu-
facturing articles of compounds of gutta percha and pitch or asphalt, whether
they be combined with other matters or not, that a great advantage is derived
by causing them to be heated to so high a degree as to assume a com-
paratively fluid state, either together or separate, and it is found preferable
that they should be caused to melt when together, though they may be first
rendered fluid separately, and then brought together and mixed whilst in the
fluid state. The most convenient means of accomplishing this mixing is by
the aid of hot water, as all burning of the substances may be prevented. For
this purpose a close vessel is used into which the substances are introduced,
roughly mixed with a quantity of water, and the temperature raised to such
a degree as to melt the gutta percha and the asphalt or pitch, and when the
substances are thus rendered fluid, they are to be well stirred, in order to
blend them well together; the quantity of water required is small, being for
the most part used to prevent the unequal heating of the other substances.
The gutta percha and asphalt or pitch having thus become well blended by
being mixed (in the proportions desired), when in comparatively fluid state,
they may be further combined with sulphur or with india-rubber, or both, and
with other matters in the ordinary manner; but when combining oxides of lead
with such compounds it is preferred to do so whilst they retain a fluid state.
In witness whereof, I, the said Charles Goodyear, have hereunto set my
hand and seal, this Twenty-seventh day of February, in the year of
our Lord One thousand eight hundred and fifty-seven.
CHARLES GOODYEAR (L.S.)
Witness,
B. GOBEY,
24, Southampton Buildings, Chancery Lane.