A NEW OR IMPROVED METHOD OF ORNAMENTING GLASS THAT IS SUBJECTED TO THE TOUGHENING OR HARDENING PROCESS
Year: 1877

page_text: LETTERS PATENT to Frederick Siemens, of Dresden, in the German Empire,
for the Invention of "A NEW OR IMPROVED METHOD OF ORNAMENTING GLASS
THAT IS SUBJECTED TO THE TOUGHENING OR HARDENING PROCESS."
Sealed the 21st August 1877, and dated the 30th May 1877.
PROVISIONAL SPECIFICATION left by the said Frederick Siemens at the
Office of the Commissioners of Patents on the 30th May 1877.
FREDERICK SIEMENS, of Dresden, in the German Empire. "A NEW OR IM-
PROVED METHOD OF ORNAMENTING GLASS THAT IS SUBJECTED TO THE TOUGHENING
OR HARDENING PROCESS.".
My Invention relates to the production of toughened glass coated with enamel or
decorated with designs or figures in enamel so firmly adhering to the glass that they
cannot be removed or obliterated without grinding off the surface. For this
purpose I apply to the glass to be decorated a powder of glass or enamel, white or
coloured; or I suspend this powder in a fluid vehicle and paint it or print it on
the glass, according to the desired design; or I apply the enamel powder or paint
by stencil plates having the design cut in them; or, having coated the whole
surface with the enamel, I apply a thin stencil plate and brush, or wipe off such
portions of the powder or paint as present themselves through the openings of the
plate, thus leaving on the glass the portions of enamel that are protected by the
metal of the plate; or, according to another method, I paint, print, or stencil the
enamel on paper, which I paste on the glass. I then heat to the required degree
the glass having on its surface the enamel, which, by partial fusion, becomes incor-
porated with the glass, and thereupon I temper or toughen the glass according to
any of the known methods for that purpose, such as plunging the glass into liquid
at a lower temperature.
I prefer however to effect the tempering or toughening of the glass by pressing it
between moulds or forms, as described in the Specification of a Patent granted to me on

page_text: the 3rd May 1875, No. 1637. Glass thus treated presents a surface indelibly
coated, with enamel all over it, or partially over it, according to any desired
design.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Siemens in the Great Seal Patent Office on the 28th
November 1877.
FREDERICK SIEMENS, of Dresden, in the German Empire.- "A NEW OR IM-
PROVED METHOD OF ORNAMENTING GLASS THAT IS SUBJECTED TO THE TOUGHENING
OR HARDENING PROCESS."
My Invention relates to the production of toughened glass coated with enamel or
decorated with designs or figures in enamel so firmly adhering to the glass that they
cannot be removed or obliterated without grinding off the surface. For this
purpose I apply to the glass to be decorated a powder of glass or enamel, white or
coloured; or I suspend this powder in a fluid vehicle and paint it or print it on the
glass, according to the desired design; or the glass may first be coated with liquid
enamel and then have enamel in the form of powder applied thereto; or I apply
the enamel powder or paint by stencil plates having the design cut in them; or,
having coated the whole surface with the enamel, I apply a thin stencil plate and
brush or wipe off such portions of the powder or paint as present themselves
through the openings of the plate, thus leaving on the glass the portions of enamel
that are protected by the metal of the plate; or, according to another method, I paint,
print, or stencil the enamel on paper, which I paste on the glass. I then toughen the
glass having on its surface the enamel, which thus becomes incorporated with the
glass. The toughening or hardening may be effected by any of the known methods,
such as, first, heating and then plunging the glass into liquid at a lower
temperature.
process
I prefer however to effect the hardening or toughening of the glass by the
described in the Specification of a Patent granted to me on the 3rd May 1875, No.
1637. Glass thus treated presents a surface indelibly coated with enamel all over
it, or partially over it, according to any desired design.
The method which I prefer to employ for ornamenting glass according to my
Invention is to coat the article with a fluid enamel which is allowed to dry, after
which the desired pattern to be produced on the glass is cut out in a thin copper
sheet, which is placed on the enamel surface, so as to allow the enamel coating on
those parts of the glass not covered by the stencil plate to be removed by a brush.
Thus the glass will receive a pattern corresponding with that of the stencil plate
by having the surface or ground surrounding the pattern coated with enamel. The
glass so prepared is then heated in a furnace to the degree required for the
toughening process, such degree varying according to the quality of the glass or to
the special toughening process to which it is to be subjected; and it is to be under-
stood that the enamel must be prepared of such ingredients as are suited for
producing a properly vitrified enamel, adhering firmly to the glass when subjected-
to the particular temperature and duration of heating required for such toughening
process. The glass is then toughened by any known process; but as before stated,
by preference, by the process previously patented by me.
The photographic process may also be employed in my before-described mode of

page_text: ornamenting the glass by transferring the desired design or picture on to it in the
same manner as is employed in ordinary photography, to be afterwards painted
over with light enamel.
Having thus described the nature of the said Invention and in what manner the
same is to be performed, I claim,―
First. The method, substantially as herein described, of ornamenting toughened
glass by applying to glass a coating of enamel, which is secured thereon by any of
the known processes employed for toughening or hardening the glass.
Second. The production of toughened glass having a coating of enamel secured
thereon in the toughening process.
In witness whereof, I, the said Frederick Siemens, have hereunto set my hand
and seal, this Twenty-sixth day of November, in the year of our Lord
One thousand eight hundred and seventy-seven.
'
FREDERICK SIEMENS. (L.S.)