IMPROVEMENTS IN ENGRAVING ON GLASS OR GLASSY SURFACES
Year: 1881

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
ENGRAVING ON GLASS OR GLASSY SURFACES." A communication from abroad
by Samuel Henry Crocker, of Railton, in the Colony of Tasmania, Mechanical
Engineer
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 9th May 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ENGRAVING ON GLASS OR GLASSY SURFACES."
A communication from abroad by Samuel Henry Crocker, of Railton, in the
Colony of Tasmania, Mechanical Engineer.
This Invention relates to an improved process of engraving on glass or glassy
surfaces, which may be applied either to the ornamentation of articles or to the
production of blocks for typographical purposes, and it consists essentially in
drawing on the said surfaces with an ink which will resist the subsequent
action of fluoric acid, and which is sufficiently fluid for the purpose when used
with a hot pen, or with any other heated drawing instrument.
The "ink" which it is preferred to employ is made of six parts by weight of
wax and six parts by weight of resin, melted together with two parts by weight of
lamp black, so as to be thoroughly incorporated the one with the other, but an ink
of any other composition which will answer the purpose may be used, the Invention
consisting in the application of such inky compositions to a glass or glassy surface
by means of a pen or other drawing instrument kept sufficiently hot to preserve
the fluidity of such composition while the drawing is being made.
The "pen" used may consist of a common steel writing pen. It is kept bot,
preferably by passing a current of electricity from galvanic batteries through
insulated wires connected with them, and arranged in the pen handle and holder to
the point of the pen, where the conducting circuit is impaired and made sufficiently
imperfect to cause the electricity to generate heat enough to melt the composition,
or by connecting a very small gas pipe or tube to the pen to convey gas to a little

page_text: gas burner fixed in such a position under the pen as will allow its flame to impart
to the pen the necessary amount of heat, or by fixing to the pen a small spirit or
other lamp; but the lamp and its appurtenances must be so very minute that the
pen to which they are fixed may be used without hindrance or inconvenience.
A brush or any other drawing instrument that will carry the ink, and that can
be kept hot may be used as a substitute for the pen.
When the drawing has been completed on the glass or glassy surface, whether it
has been made as an ornament to an article or to be used as an engraving for
typographical purposes, I cover such surface with fluoric acid, or with its
equivalent sulphuric acid, and finely divided fluor spar until those parts not
protected by the ink have been etched or engraved deep enough for the purpose
required; I then wash, the whole with cold water. If the object has simply been
ornamentation the process is now complete, but if the object has been to prepare an
engraving for typographical purposes, I take the engraved surface, which in this
case should be in the face of a block of thick glass, cut it to the required size,
bevel off the edges, and to prevent fracture mount and firmly secure it to a
metal backing of any required thickness by means of shellac, glue, or any other
sufficiently adhesive substance. The block is then complete and may be printed
from direct or from electro or stereo-types, which can be taken from it as freely
as from a wood block.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
24th October 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ENGRAVING ON GLASS OR GLASSY, SURFACES."
A communication from abroad by Samuel Henry Crocker, of Railton, in the
Colony of Tasmania, Mechanical Engineer.
The said Invention relates to an improved process of engraving on glass or glassy
surfaces, which process may be applied either to the ornamentation of articles or to
the production of blocks for typographical purposes, and it consists essentially in
drawing on the said surfaces with an ink which will resist the subsequent action of
fluoric acid or its equivalent, and which is sufficiently fluid for the purpose when
used with a hot pen, or with any other heated drawing instrument.
The ink which it is preferred to employ is made of six parts by weight of
wax and six parts by weight of resin, melted together with two parts by weight of
lamp black, so as to be thoroughly incorporated the one with the other, but an ink
of any other composition which will answer the purpose may be used, the Invention
consisting in the application of such inky compositions to a glass or glassy surface
by means of a pen or other drawing instrument kept sufficiently hot to preserve
the fluidity of such composition while the drawing is being made.
The "pen" used may consist of a common steel writing pen. It is kept hot,
preferably by passing a current of electricity from galvanic batteries through
insulated wires connected with them and arranged in the pen handle and holder, the
current being conducted to the point of the pen where the conducting circuit is
impaired and made sufficiently imperfect to cause the electricity to generate heat
enough to melt the composition, or by connecting a very small gas pipe or tube to
the pen to convey gas to a small gas burner fixed in such a position under the pen
as will allow its flame to impart to the pen the necessary amount of heat, or by
fixing to the pen a small spirit or other lamp, but the lamp and its appurtenances
should be so very minute that the pen to which they are fixed may be used without
hindrance or inconvenience. A brush or any other drawing instrument that will
carry the ink and that can be kept hot may be used as a substitute for the pen.
When the drawing has been completed on the glass or glassy surface, whether it
has been made as an ornament to an article, or to be used as an engraving for
typographical purposes, such surface is covered with fluoric acid, or with its
equivalent sulphuric acid, and finely divided fluor spar until those parts not
protected by the ink have been etched or engraved sufficiently deep for the purpose
required, and the whole is then washed with cold water. If the object has simply
been ornamentation the process is now complete, but if the object has been to
prepare an engraving for typographical purposes, the engraved surface (which in
this case should be on the face of a block of thick glass) is taken and cut to the
required size, the edges are bevelled off, and to prevent fracture the glass is
mounted and firmly secured to a metal backing of any required thickness by means
of shellac, glue, or other sufficiently adhesive substances. The block is then
complete and may be printed from direct or from electro or stereo-types, which can
be taken from it as freely as from a wood block.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is,-
The improved process of engraving on glass or glassy surfaces by drawing

page_text: thereon with a hot pen, or with any other heated drawing instrument which melts
and maintains fluid, an ink capable of resisting the subsequent action of fluoric
acid or its equivalent, substantially in the manner herein before described.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification set my hand and seal, this Nineteenth day of October, One
thousand eight hundred and eighty one.
J. HENRY JOHNSON. (L.S.)