A NEW METHOD OF ORNAMENTING OF ALL KINDS OF GLASS IN IMITATION OF ENGRAVING OR ETCHING, BY MEANS OF WHICH BORDERS, CYPHERS, COATS-OF-ARMS, DRAWINGS, AND THE MOST ELABORATE DESIGNS MAY BE EXECUTED IN A STILE OF ELEGANCE HITHERTO UNKNOWN, AND WHICH CANNOT POSSIBLY BE EQUALLED BY THE USUAL AND CUSTOMARY MODE OF ETCHING OR ENGRAVING AS HITHERTO PRACTISED
Year: 1806

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
DAVENPORT, of Longport, in the Parish of Burslem, in the County of Stafford,
Glass Maker, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Fourth day of July,
in the forty-sixth year of His reign, give and grant unto the said John
Davenport, his exors, admors, and assigns, His especial licence, that the said
John Davenport, his exors, adiñors, and assigns, should and lawfully might,
during the term of years therein mentioned, make, use, exercise, and vend,
within England, Wales, and Town, of Berwick-upon-Tweed, his Invention of
"A NEW METHOD OF ORNAMENTING OF ALL KINDS OF GLASS IN IMITATION OF
ENGRAVING OR ETCHING, BY MEANS OF WHICH BORDERS, CYPHERS, COATS-OF-ARMS,
DRAWINGS, AND THE MOST ELABORATE DESIGNS MAY BE EXECUTED IN A STILE OF
ELEGANCE HITHERTO UNKNOWN, AND WHICH CANNOT POSSIBLY BE EQUALLED BY THE
USUAL AND CUSTOMARY MODE OF ETCHING OR ENGRAVING AS HITHERTO PRACTISED;"
in which said Letters Patent there is contained a proviso obliging the
said John Davenport, by an instrument in writing under his hand and seal,
to cause a particular description of the nature of his said Invention, and in
what manner the same is to be performed, to be inrolled in His Majesty's
High Court of Chancery within one calendar month after the date of the
said recited Letters Patent, as in and by the same, relation being thereunto
had, may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Davenport, do hereby declare that my said Invention is by coating an'l

page_text: afterwards etching, engraving, and chasing on the glass so coated, and the
manner in which the same is to be performed is described and ascertained
as follows:
The method heretofore used for engraving and designing borders, &c. on
glass has been by means of a machine, with wheels of different substances,
which have been employed with a sharp stone or sand to grind off some parts
of the surface of the glass which is to be engraved upon, and then by means
of grinding and polishing different parts on the rough surface, the different
borders, figures, &c. &c., are formed according to the designs given, or at
the will of the operator, and the usual method of grinding window glass for
the purpose of making blind windows has been by means of a machine
moving on the surface of the glass in contact with sand or a sharp stone, or
the like substances applied by the hand, thereby grinding off the polished
surface, leaving the glass sufficiently opake to prevent any objects being
clearly distinguished through it, and yet affording sufficient light for common
purposes. Now, the present Invention and object of this Patent, instead of
grinding or taking off any part of the surface of the glass as aforesaid, is to
lay on an additional surface or coating of glass prepared for that purpose,
which, when subjected to a proper degree of heat, will incorporate with the
surface of the glass operated upon so as to produce an effect similar to that
which has heretofore been obtained by means of grinding as before mentioned;
and when it is required that the glass should be ornamented with any
borders, cyphers, or designs, &c., then previous to the heat being applied, with
an etching or engraving or chasing tool, or any other pointed instrument of
metal, bone, wood, or any other hard substance, to ctch out, engrave, chase,
or work out such parts of the surface or coating so laid on as will produce
an effect similar but greatly superior to the effect heretofore produced by the
usual mode of grinding and polishing with wheels as before mentioned; and the
method I use is as follows:-When I want to prepare the glass for coating
1 take one or more of the smallest pots in the furnace, called by the glass
makers pile end pots, or I take any small or large pot or crucible, suitable
for the purpose, according to the quantity wanted, which I fill in the usual
mode with a batch or batches of materials made up in the same manner as
it is used for the making of best flint glass, the article of broken glass, or
what the glass makers termi cullitt, being the principal ingredient therein,
and the proportions I have used with most advantage are as follows:-For
mixture No. 1, for 160 parts of cullett or broken glass take ten parts of
pearl ashes, forty parts red lead, and ten parts of arsenic. For mixture No. 2,
for 120 parts of cullett or broken glass, 160 parts of red lead, 60 parts of

page_text: sand or siliceous earth, and sixty parts of borax. For mixture No. 3, 70
parts red lead, 22 parts of sand or siliceous earth, and 40 parts of calcin'il
borax. When the above mixtures have been subjected to a degree of
heat in the furnace sufficient to obtain a complete fusion or vitrification
of the substances employed, I then take of each mixture, in equal parts,
the quantity which is to be ground and levigated into an impulpable
powder, and to be mixed with a menstruum proper for coating the glass
as hereafter described. In those works wherein the glass makers use
litharge instead of red lead, it may be substituted in the above mixtures in
lieu thereof, and other proportions of the above ingredients or others of a
like quality, will produce nearly a similar effect, or they may be compounded
in one or more mixtures instead of three, but the most perfect and beautiful
specimens were produced by the combination as above specified.
But I do not claim any exclusive right by this Patent for the making of
this glass, but for the Invention of applying it to coat the surface of other
glass, and for operating upon it in a manner entirely new, as herein described,
and for producing by these means an effect superior and different from any
thing heretofore produced. This glass may be levigated in any of the usual
modes, taking care that no injurious substance is introduced, and that the
utmost degree of fineness is obtained which the powder is capable of, and for
this purpose I prefer using a small mill, with a pan, the bottom and sides of
which are strong glass, with a grinder or levigator, cast also of solid glass, to
work therein. When the glass is sufficiently levigated it may be mixed with
the menstruum hereafter described, either in a wet state as it comes from the
mill, or it may be dried into the state of powder, as most convenient. To
prepare the menstruum which I use for the purpose of mixing with and for
laying on the ground glass, I take one part of double refined loaf sugar,
dissolved in two parts of pure water, to which is added at the time of mixing
up the powder about one third part of common writing ink, the component
parts of which are universally known, or of a watery solution of calcin'd
copperas. The effect produced by the addition of either of these latter
substances I take to be similar to that which is produced by the addition of
the oxyd of manganese used in a small quantity by the glass makers in making
their best flint glass, because without such addition I have found the speci-
mens had more of a cloudy or milky appearance, somewhat similar to what
is termed by the workmen in the glass-house shoppy metal, and which quality
and appearance it is understood the addition of the afore-mentioned oxyd
tends to eradicate and destroy. The oxyd of manganese, or possibly other
oxyds, may produce the same effect here; but the above specified substances

page_text: or cither of them are sufficiently cheap to warrant their general use, and
I have found them to answer every purpose required. Of the above com-
pound menstruum I then add in manner aforesaid a quantity sufficient to
render the ground mixture or powder of a proper consistence for laying on
with a very thin and even surface, and which necessary quantity and consis-
tency, as well as the necessary thickness of the coating to be laid on, the
operator will soon and easily ascertain, and as in the course of working or
laying on the mixture some of the watery particles will evaporate, he will
add, as occasion requires, the necessary quantity of the solution of sugar for
the purposes saforesaid. The advantages which I have found in the discovery
of the use of this simple mixture of sugar and water is, that whenever I have
made use of any of the essential oils, gums, resins, and many other substances
which have been tried, the coating became set so fast on the surface that the
workmen could with difficulty procced, and the delicate parts of the designs
could not be etched out with that nicety and precision required, whereas tho
above menstruum rendered the coating sufficiently fast to prevent the surface
from being rubbed off while the work was under hand, and when the workman
wished to operate on any particular part of the surface he had only to breathe
upon that part, by which means the menstruum imbibes moisture from his
breath, and the mixture becomes soft and pliable to his tool, while those parts not
breathed upon remain fast as before. There may be other substances which
might produce the effect and answer the purpose of the above menstruum, but
I have found this to possess all the advantages required. When the coating
or mixture is prepared as aforesaid, I then proceed to coat the surface of the
glass to be operated upon by means of brushes of squirrels' or camels' hair, or
any fine animal hair, or any other substance which is capable of laying it on
with a very thin and even surface; and the most convenient form for that pur-
pose is to have the points of the hair and other substances spread out, and so
disposed as to form a crescent or segment of a circle, the size according
with the size and nature of the work to be performed. After this coating has
been applied evenly over the surface of the glass, and if no parts thereof are
intended to be polished or worked out, the glass is then exposed to a heat
sufficient to produce a semivitrification of the coated surface, and to incor-
porate it sufficiently with the substance or body of glass so coated, but great
care must be had not to extend the degree of heat further than is necessary
for these purposes, because in that case a complete vitrification of the coating
would ensue, whereby the desired effect of having a surface in imitation of
the rough surface produced by grinding would not be obtained; and, although
when this happens the article may be recoated, and again submitted to the

page_text: fire, the loss of labor would be considerable thereon, but which by a proper
attention to the necessary degree of bent may be easily avoided. And if
after this coating has been applied, any borders, cyhers, coats-of-arms, or
other ornamental designs are wanted to be executed thereon, then previous
to the heat being applied with an etching or engraving or chasing tool, or
any other pointed instrument of metal, bone, wood, or any other hard
substance, I work out, etch, or engrave, and chase out such part or parts of
the coated surface so laid on as will produce the desired effect, after which I
subject the article or articles to the requisite degree of heat as before
mentioned. This Invention is not only applicable to all kinds of useful and
ornamental articles of glass ware, whereon the common methods of engraving
hath been practised, but may be applied to window glass and plate glass of
every description, in place of grinding as aforesaid, for the purpose of making
blind windows, and the method of etching, engraving, and chasing thereon
is peculiarly adapted to produce beautiful specimens of art for the windows
of altar-picces, libraries, museums, coach windows, ornamental buildings of all
descriptions, and all other purposes wherein plato glass and window glass has
been commonly used. This Invention has also an advantage over the common
method by the work wearing much cleaner than the work of ground glass,
the surface of which being somewhat fractured by the action of the wheel, &c.
is therefore liable to gather dirt on the rough unpolished parts of the borders
or designs so executed, a fault which has been very much complained of.
In testimony whereof, I have hereunto set my hand and seal, this First
day of August, in the year of our Lord One thousand eight hundred