IMPROVEMENTS IN THE MANU- FACTURE OR TREATMENT OF GUTTA PERCHA
Year: 1856

page_text: LETTERS PATENT to Emory Rider, of Cannon Street, in the City of
London, Gentleman, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OR TREATMENT OF GUTTA PERCHA," being improvements upon the
Invention secured to me by Letters Patent, dated the 20th day of
July 1852.
Sealed the 29th May 1857, and dated the 3rd December 1856.
PROVISIONAL SPECIFICATION left by the said Emory Rider at the Office
of the Commissioners of Patents, with his Petition, on the 3rd
December 1856.
I, EMORY RIDER, of Cannon Street, in the City of London, Gentleman, do
hereby declare the nature of tho said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OR TREATMENT OF GUTTA PERCHA," being improvements upon the
Invention secured to me by Letters Patent, dated the Twentieth day of July,
One thousand eight hundred and fifty-two, to be as follows:-
This Invention relates and has especial reference to certain improvements
already patented by me, which consist in treating gutta percha in its raw
state by the action of heat, so as to expel the volatizable ingredients there-
from, and render the same fit for the after processes of vulcanization.
In carrying out the above Invention, I bave discovered that I produce a

page_text: better effect by adding to the raw gutta percha a quantity of sulphur and.
litharge, or other dryers, before subjecting the gutta percha to the preliminary
heating process. When these materials have been incorporated, the mass is
then subjected to a heat of from two hundred and thirty to two hundred and
fifty degrees Fahrenheit.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Emory Rider in the Great Seal Patent Office on the
3rd June 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EMORY
RIDER, of Cannon Street, in the City of London, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of December, 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 Emory Rider, Her special license that I, the said Emory Rider, my
éxecutors, administrators, and assigns, or such others as I, the said Emory
Rider, my executors, administrators, or 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 MANU-
FACTURE OR TREATMENT OF GUTTA PERCHA," being improvements upon the In-
vention secured to me by Letters Patent, dated the 20th day of July 1852,"
upon the condition (amongst others) that I, the said Emory Rider, by an
instrument in writing under my hand and seal, 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 Scal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Emory Rider, do hereby declare the
nature of my 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.
My said Invention relates and has especial reference to certain improve-
ments already patented by me on or about the Twentieth day of July, One
thousand eight hundred and fifty-two, which consists in treating gutta percha

page_text: in its raw state by the action of heat, so as to expel the volatizable ingredients
therefrom, and render the same fit for the after processes of vulcanization.
In carrying out the above Invention, I have discovered that I produce. a.
better effect. by adding to the raw gutta percha a quantity of sulphur and
litharge, or other dryers, before subjecting the gutta percha to the preliminary.
heating process. When these materials have been incorporated, the mass is
then subjected to a heat of from two hundred and thirty to two hundred and
fifty degrees Fahrenheit..
I have found one part of sulphur, or the equivalent thereof, added to sixty-
six parts of gutta percha when separated from its solid impurities, and one part
of litharge, suitable for effecting this purpose.
The sulphur or byposulphito of lead or zinc, or the artificial sulphuret of
lead, or other equivalent of sulphur, should be thoroughly mixed or incorporated
with the gutta percha, by passing the gum and the dryers repeatedly between
metallic rollers heated to a temperature sufficient to make the gutta percha
very soft, and, easily kneaded or worked. The mode of effecting this I have
found in practice most beneficial is by the employment of a machine in which
the rollers work at different degrees of speed, and produce a tearing or grinding
action, of considerable importance in working the material.
The incorporated material having been ground, is then placed in a strong
metal vessel or vessels, care being taken, however, that the material does not
occupy more than one-third of the capacity of tho vessels, so as to leave due
allowance for the swelling or expansion of the material when under the action
of heat. The material is then exposed to a temperature of about two
hundred and thirty-five to two hundred and forty-five degrees Fahrenheit for
a space of about three hours, so as to give a nearly uniform temperaturo
throughout the mass; but the actual time depends to a great extent upon
the nature of the gum, the degree of heat employed, and the quantity and
state of aggregation of the material at the time the heating is commenced.
The heat employed may be either by the action of steam or hot air; but I
prefer the employment of steam, by which I am enabled to subject the gum
under treatment to a greater pressure, and to obtain a more regular degree of
heat than by any other means.
The gutta percha having undergone this preliminary heating, may be
vulcanized by the application of a much lower degree of heat than has been
ordinarily used in that process; I have found a temperature of from two
hundred and fifty-five to two hundred and sixty-five degrees Fahrenheit to be
sufficient to effect the change.
Having now described and particularly ascertained the nature of my said

page_text: Invention, and the manner in which the same is or may be used or carried into
effect, I would state what I consider to be novel and original, and there-
fore claim as the Invention secured,-the modo of treating gutta percha, by
the addition to 66 parts of that gum of one part of sulphur, or an equivalent
thereof, and one part of litharge, prior to the exposure of the same to the
action of 235 to 245° Fahrenheit, for the purpose of expelling the volatizable
ingredients therefrom, and the after process of vulcanization of gum so
prepared, by subjecting the same to a heat of 255° to 265° Fahrenheit.
In witness whereof, I, the said Emory Rider, have hereunto set my
hand and seal, the Twenty-ninth day of May, One thousand eight
hundred and fifty-seven.
EMORY RIDER. (L.B.)