IMPROVEMENTS IN THE MANUFACTURE OF WINDOW AND OTHER GLASS
Year: 1845

page_text: BEDFORD'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAAC
HAWKER BEDFORD, of Birmingham, in the County of Warwick, serid greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain; bearing date at
Westminster, the Twelfth day of December, in the ninth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Isaac
Hawker Bedford, my exors, adñiors, and assigns, Her especial licence; full
power, sole privilege and authority, that I, the said Isaac Hawker Bedford,
my exors, adiñiors, and assignis, or such others as I; the said Isaac Hawker
Bedford, my exors, admors, or assigns, should at any time agree with, and no
others, from time to time and at all times during the term of years therein
expressed, should and lawfully might inake, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF WINDOW AND OTHER GLASS," (partly
invented by me, and partly communicated by a foreigner resident abroad); in
which said Letters Patent is contained a proviso, that I, the said Isaac Hawker
Bedford, shall cause à particular description of the nature of the said
Invention, and in what manner the same is to be performed, to be inrolled in
Her said Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and at
large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Isaac Hawker Bedford, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, are fully described
and ascertained in and by the following statement thereof, that is to say :-
The Invention consists, first, of improvements in staining sheet glass, and
also vessels and other articles made of glass; and secondly, the Invention
consists of improvements in etching sheet glass, and also vessels and other
articles made of glass.
And in order that the Invention may be fully understood and readily carried
into effect, I will proceed to describe the means pursued by me, and first in
respect to that part of the Invention which relates to staining glass which has
for its object the use of copper in staining articles made of glass so as to
produce a red color. The sheet glass or vessels or other articles of glass are
to be made in the usual way, and when articles of cut glass are to be stained
they may be stained before or after cutting and polishing, and the staining may
cover the whole or any part or parts of the surface.. I would however remark
that this part of the Invention is performed most successfully with those
descriptions of glass which are made without the use of soda. The articles of
glass being made and their surfaces well cleaned, I treat them in the following
inanner: I take one part by weight of sulphuret of copper, two parts of the
scales of iron obtained from a smith's forge, three parts sulphate of copper
burned to whiteness, and four parts of calcined yellow ochre; these are ground
as finely as possible with the essence of turpentine, and I find that it is
desirable to 'mix with such turpentine a small quantity of the essence of
turpentine which has become rather thick by long exposure to the atmosphere,
which prevents the mixture chipping off after becoming dry on the glass.
The mixture thus obtained and being of the consistency of cream is laid on by
a brush to the surface of the glass desired to be stained, and allowed to dry;
the articles of glass are then to be placed in a usual stainer's muffle, and heated
to as high a degree of heat as the glass will allow of without melting; and it
is desirable to state that the color obtained is better the higher degree of heat
the particular glass will allow of; the fire is then drawn off, and the article of
glass allowed to cool down slowly. The articles of glass are washed when cold,
when the appearance of the glass should, on looking in a direction edgewise of
the glass, offer a greenish yellow if lead has been used in the making of the
glass; the color obtained will however differ according to the composition of
the glass. The articles of glass are again placed in a muffle, and again heated
to the degree above mentioned, and then the fire is withdrawn, and a quantity
of small coal is then introduced into the lower part of the muffle, and for this

page_text: purpose it is convenient to have the cover of the muffle in two parts, so that. a
small part of the cover at the lower part of the muffle may be removed to
allow of a shallow tray being slided into the muffle under the articles of glass
placed on the perforated shelves above. The quantity of coal I introduce is
5 four pounds in a muffle, twenty-four inches in diameter, and thirty inches in
length. The muffle is then to be completely closed and luted, by which the
products of the coal will be prevented escaping. The muffle and the articles
of glass are to be allowed to cool down, and when cold the articles of glass are
to be taken out, and they will generally be found to offer a brownish red color
on looking through them. Those articles which offer such color are then to
be placed in another muffle which has been lime-washed, and again heated up
to the same degree of heat as before mentioned; the fire is to be removed and
the muffle and the articles of glass cooled down, and when cold the articles of
glass should offer the red color desired. It should be stated that a red color
of the depth and tone desired, is not at all times obtained by going once through
the process above explained, in which cases the articles are again and again to
be subjected to the same processes; a workman will, however, with care, after
some experience, be able to judge whether the effect desired has been obtained
by each part of the process, and if not, he will not carry such articles through
the remainder of the process, but will repeat the previous part or parts of the
process till the appearance desired has been obtained. I would remark in
respect to this part of the Invention, although I have thus been particular in
describing the exact details of the process as practised by me, I do not confine
myself thereto, so long as copper is used when staining articles made of glass,
so as to obtain a red color.
I will now proceed to describe the second part of the Invention, which has
for its object the ornamenting of glass by a peculiar process of etching. In
carrying out this part of the Invention when ornamenting window glass, I- take
five parts of puce-colored oxide of lead (peroxide) to one part of flux, and the
flux I employ is seventeen parts of glass of borax, and thirteen parts of red
lead fused together, and I grind the oxide of lead and the flux with turpentine,
and with this composition the artist paints the desired devices or designs on to
the surface of glass to be etched; and I would state that when colored glass is
to be etched; I prefer acetate of lead, in place of the oxide of lead above men-
tioned; the same are then allowed to dry, and the articles are to be fired in the
same manner as when gilding on glass, and then the articles are allowed to cool
and when cold they are dipped in a weak solution of nitric acid in water, and
so soon as the painted designs are acted on, the articles of glass are to be placed
in water, and the surfaces are to be cleansed by rubbing off the preparation

page_text: above mentioned. In this part of my Invention, I have also been particular
in giving the exact details of the process as practised by me; I do not however
confine myself to the details, so long as lead is used and removed by acid.
Having thus described the nature of the Invention, I would wish it to be
understood, that what I claim is,―
First; the mode of manufacturing stained window or other glass by applying
copper for producing a red color for staining the same on the surfaces as herein
explained.
And secondly, I claim the mode of manufacturing window and other glass
by etching on the surfaces thereof, by means of lead acted on by acid.
In witness whereof, I, the said Isaac Hawker Bedford, have hereunto
set my hand and seal, this Eleventh day of June, in the year of 'our
Lord One thousand eight hundred and forty-six.
ISAAC HAWKER (L.s.) BEDFORD.
AND BE IT REMEMBERED, that on the Eleventh day of June, in the
year of our Lord 1846, the aforesaid Isaac Hawker Bedford came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Twelfth day of June, in the year of our Lord One thousand
eight hundred and forty-six.