IMPROVEMENTS IN THE MANUFACTURE OF FLINT GLASS
Year: 1862

page_text: LETTERS PATENT to Thomas George Webb, of Manchester, in the
County of Lancaster, Glass Manufacturer, for the Invention of "In-
Sealed the 28th January 1868 and dated the 1st August 1862.
PROVISIONAL SPECIFICATION left by the said Thomas George Webb at
the Office of the Commissioners of Patents, with, his Petition, on the
1st August 1862.
I, THOMAS GEORGE WEBB, of Manchester, in the County of Lancaster,
Glass Manufacturer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF FLINT GLASS," to be as follows:-
My Invention has for its object a reduction of the expense in manufacturing
flint glass, with which view I use sulphate or muriate of potash in place of or
in combination with the carbonate commonly employed. In carrying out this
improvement I in the first place mix the siliceous substance with the sulphate
of potash, and I subsequently add the lead ordinarily employed, using a second
heat if found necessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas George Webb in the Great Seal Patent Office on
the 81st January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
GEORGE WEBB, of Manchester, in the County of Lancaster, Glass Manu-
facturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of August, in the year of our
Lord One thousand eight hundred 'änd sixty-two, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas George Webb, Her special license, that I, the said Thomas
Georgo Webb, my executors, administrators, and assigns, or such others as I,
the said Thomas George Webb, my executors, administrators, and assigns, should
at 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
"IMPROVEMENTS IN THE MANUFACTURE OF FLINT GLASS," upon the condition,
amongst others, that I, the said Thomas George Webb, by an instrument
in writing under my hand and seal, should particularly describe and ascer-
tain the nature of the said Invention, and in what manner the samo was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Thomas George Welib, do hereby declare
the nature of my said Invention, and in what manner the shime is 'to be per-
formed, to be particularly described and ascertained in and by the following
statement (that is to say) :-
My Invention has for its object a reduction of the expense of manufacturing
flint.glass, with which view I use sulphate or muriate of potash in place of or
in combination with the carbonate commonly employed. In carrying out
this improvement, I, in the first place, mix the silicious substance with the
sulphate of potash, and I subsequently add the lead ordinarily employed. The
proportions of the several materials will necessarily be varied according to the
degree of purity of the sulphate or muriate of potash employed, the quantity.
to be used (with the best effect) being such as will combine with the whole
of the silicic acid present. Taking ordinary commercial sulphate of potash
and ordinary sand used in the manufacture of glass, I have found equal

page_text: weights to answer the purpose. These materials are well mixed mechanically
and placed in an open pot such as is used in the manufacture of crown bottle
glass, such pot being in a furnace and sufficient heat applied to effect the
decomposition of the sulphate of potash, which decomposition is known as
usual by the materials having become fluid. This part of the process may be
assisted by the addition of carbonaceous matters. This silicate of potash is
removed from the pot and is thrown into cold water or is otherwise cooled,
and then constitutes a material which may be converted into "flint glass " by
the addition of metallic oxides. This conversion is effected by the addition
of a further quantity of sand and oxide of lead, these two substances being in
proportions to each other which may be varied as is well known in the manu-
facture of glass. The whole is then placed in the ordinary covered pot of a
flint glass furnace and fluxed in the usual manner. I have above particularly
alluded to sulphate of potash, but according to my Invention I use muriate of
potash in place thereof and after the manner above described. I would observe
that although I have described the sulphate of potash as used entirely in place
of the carbonate, yet I do not confine myself thereto, as the two substances or
combinations thereof with other substances may be used if desired, and the
same observation applies to the muriate of potash. I would also observe that
I do not limit myself to the precise course of operations above pointed out,
but claim as secured to me under the above in part recited Letters Patent,
the use of sulphate of potash and muriate of potash alone or in combination
with other substances for the purpose above set forth.
In witness whereof, I, the said Thomas George Webb, have hereunto
set my hand and seal, this Thirtieth day of January in the year
of our Lord One thousand eight hundred and sixty-three.
THAN
DAN WEDD