IMPROVE- MENTS IN THE MANUFACTURE OR TREATMENT OF INDIA-RUBBER OR GUTTA PERCHA, OR COMPOUNDS THEREOF, APPLICABLE TO THE PRODUCTION OF STEREO- TYPE PLATES, AND OTHER FORMS
Year: 1865

page_text: in the United States of America, but now residing at Red Lion Court,
Fleet Street, in the City of London, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OR TREATMENT OF INDIA-RUBBER OR GUTTA
PERCHA, OR COMPOUNDS THEREOF, APPLICABLE TO THE PRODUCTION OF STEREO-
TYPE PLATES, AND OTHER FORMS."
Sealed the 31st October 1865, and dated the 5th May 1865.
PROVISIONAL SPECIFICATION left by the said Thomas Jefferson Mayall
at the Office of the Commissioners of Patents, with his Petition, on the
5th May 1865.
I, THOMAS JEFFERSON MAYALL, of Roxbury, Massachusetts, in the United
States of America, but now residing at Red Lion Court, Fleet Street, in the
City of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OR TREATMENT OF INDIA-RUBBER OR GUTTA
PERCHA, OR COMPOUNDS THEREOP, APPLICABLE TO THE PRODUCTION OF STEREOTYPE
PLATES, AND OTHER FORMS," to be as follows:-
The improvements relate to taking india-rubber or gutta percha, or con-
pounds thereof, combined with sulphur when in a semi or partially converted
state, by the action of the sulphur and heat, and then applying such matters
under pressure and heat to the surface to be stereotyped or copied, and con-
tinuing the pressure and heat until perfect conversion.
The process I follow is to combine with every pound weight of the india-

page_text: rubber or gutta percha, or the compounds thereof 6 oz. of sulphur, or
thereabouts, and I effect the combination by an ordinary grinding or com-
pounding machine, and when the combination is complete I reduce the mass
to a sheet or layer by rolling or calendering with heated rolls. The sheets or
surfaces I then submit to the action of heat in a chamber, for, say, 3 hours, at
a temperature of 235 Fab., or thereabouts, but for a longer time less heat
may be employed, whilst for a shorter time a higher temperature may be
adopted, the object being to produce a partial conversion of the compound,
when I apply it to the surface of the stereotype mould or other surface to be
copied, aided by pressure and heat until the desired conversion is fully effected,
and I prefer that the heat be applied to the hollow plates by which the pressure
is exerted. To facilitate the speedy cooling of the compound when an im-
pression has been obtained, I prefer to clamp the compound and the mould
between a separate pair of plates applied between the parts of the press, and
which may then be readily removed and placed in water for cooling.
The improvements are particularly applicable to obtaining clear, definite,
ornamental, or other outline or figure.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Jefferson Mayall in the Great Seal Patent Office on
the 4th November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
JEFFERSON MAYALL, of Roxbury, Massachusetts, in the United States of
America, but now residing at Red Lion Court, Fleet Street, in the City of
London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of May, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Thomas Jefferson Mayall, Her special licence that I, the said Thomas Jefferson
Mayall, my executors, administrators, and assigns, or such others as I, the said
Thomas Jefferson Mayall, my executors, administrators, and assigns, should
nt 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 "Im-
PROVEMENTS IN THE MANUFACTURE OR TREATMENT OF INDIA-RUBBER OR GUTTA

page_text: PERCHA, OR COMPOUNDS THEREOF, APPLICABLE TO THE PRODUCTION OF STEREOTYPE
PLATES, AND OTHER FORMS," upon the condition (amongst others) that I, the
said Thomas Jefferson Mayall, my executors or administrators, by an instru-
ment 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Jefferson Mayall, 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 :-
In carrying out my improvements in the manufacture or treatment of india-
rubber or gutta percha, or compounds thereof, I take the india-rubber or
gutta percha, or compounds thereof when combined with sulphur, and in a
semi or partially "converted" state, produced by the action thereon of the
sulphur, aided by heat, and then in this partially "converted" state I apply
such matters under pressure and heat to the surface to be stereotyped or
copied, and I continue the pressure and heat until perfect conversion is
obtained. By the terms "conversion" and "converted," I mean that state
of the material which is otherwise called "vulcanized" or "cured."
In carrying out my improvements I combine with every pound weight of
the india-rubber or gutta percha, or compound thereof, 6 ozs. of sulphur, or
thereabouts, and I effect the combination by an ordinary grinding or com-
pounding machine, and when the combination is complete 1 reduce the mass
to a sheet or layer by rolling or calendering with heated rolls. The sheets
or surfaces obtained 1 then submit to the action of heat in a chamber, for,
say,
3 hours, at a temperature of 235° Fahrenheit, or thereabout, but for
a longer time less heat may be employed, whilst for a shorter time a higher
temperature may be adopted, the object being to produce a partial "con-
version" of the compound, and when this partial "conversion" of it has been
obtained, I apply it to the surface of the stereotype mould or other surface to
be copied, and I apply further pressure and heat until the desired "con-
version" is fully effected. I prefer that the heat be applied to the hollow
plates by which the pressure is exerted. To facilitate the speedy cooling of
the compound when an impression has been obtained, I prefer to clamp the
compound and the mould between a separate pair of plates applied between
the parts of the press, so that they may then be readily removed and placed
ju water for cooling.

page_text: The improvements are particularly applicable to obtaining clear, definite,
ornamental, or other outline or figure.
Having thus described my Invention, and means which I adopt in
carrying the same into effect, I would have it understood that I do not
confine myself to the precise details given, as these may be varied; but what
I claim is, the manufacture or treatment of india-rubber, gutta percha, or
compounds thereof, for the production of stereotype plates and other forms,
iu manner substantially as explained.
In witness whereof, I, the said Thomas Jefferson Mayall, have here-
unto set my hand and seal, this Fourth day of November, in the year
of our Lord One thousand eight hundred and sixty-five.
THOS. J. MAYALL. (L.S.)