IMPROVEMENTS IN THE MANUFACTURE OF GLASS AND CLAY WARES
Year: 1855

page_text: LETTERS PATENT .to Thomas Richardson, of Portland Place, Newcastle-
on-Tyne, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
GLASS AND CLAY WARES."
Sealed the 18th January 1856, and dated the 23rd October 1855.
PROVISIONAL SPECIFICATION left by the said Thomas Richardson at the
Office of the Commissioners of Patents, with his Petition, on the 23rd
October 1855.
I, THOMAS RICHARDSON, of Portland Place, Newcastle-on-Tyne, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF GLASS AND CLAY WARES" to be as follows:-
This Invention has for its object the application of native borate. of lime,
either alone or fritted with a salt of soda, in the manufacture of glass and clay
wares.
For this purpose native borate of lime is freed, by washing or otherwise,
from sand and other impurities, in which state it may be used as a substitute
for borax. Or the native borate of lime is mixed with a salt of soda, and the
whole is reduced to powder, and fritted at a moderate heat, and the resulting
material may be used in the place of borax.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Richardson in the Great Seal Patent Office on the
11th April 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
RICHARDSON, of Portland Place, Newcastle-on-Tyne, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by .Her Letters
Patent, bearing date the Twenty-third day of October, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Richardson, Her special licence that I, the said Thomas
Richardson, my executors, administrators, and assigns, or such others as I, the
said Thomas Richardson, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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 GLASS AND CLAY WARES," upon the condition (amongst others)
that I, the said Thomas Richardson, my executors or administrators, by an
instrument in writing under my; or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same 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 Richardson, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention has for its object the application of native borate of lime,
either alone or fritted with a salt of soda, in the manufacture of glass and clay
wares. For this purpose native borate of lime is freed, by washing or otherwise,
from sand and other impurities, in which state it may be used as a substitute
for borax. Or the native borate of lime is mixed with a salt of soda, and the
whole is reduced to powder and fritted at a moderate heat, and the resulting
material may be used in the place of borax.
Borate of lime as imported into this country contains various impurities,
one portion soluble and another-insoluble in water. As these impurities affect
the value of the borate of lime in some of its applications, I levigate the
native mineral in a manner-similar- to- that in practice in color works, and

page_text: admit a small jet of steam into the dolly tub to promote the purification.
The sand and coarser impurities are separated in the dolly, while the finely
divided borate of lime flows on through the spouts into tanks, where it sub-
sides, leaving the soluble impurities in solution in the supernatant liquid, which
may be syphoned or run off. The borate of lime is dried in dishes in stoves,
or in reverberatory furnaces, with a gentle surface heat, and occasional agi-
tation by the workman. For coarser wares and inferior qualities of glass it is
unnecessary to carry the purification to such an extent. The adhering sand
and other impurities may be removed by simply brushing off the sand or
impurities from the masses, or exposing them to a current of water.
The purified borate of lime in powder may be employed as a substitute for
borax in the manufacture of frits for clay wares. I am aware that previous to
this Patent, borate of lime in its natural state was, at my suggestion, publicly
used in glazing certain clay wares; but owing to the impurities present the
color of the ware was more or less injured, which I have since found to be
obviated by employing borate of lime, purified as above explained.
I find in practice that for every hundred parts of borax a quantity of borate
of lime, containing a like quantity of boracic acid, should be used in preparing
a frit, with borate of lime in place of borax. Or I take the purified borate
of lime, and mix with it a quantity of soda, which I prefer to use in the form
of carbonate, in the proportion of one part of the latter to four parts of the
former, and expose them to a gentle heat in a close furnace. The resulting
material may be used to replace the equivalent quantities of borax and whiting
in the frits or glazes employed in manufactories of clay wares. The above
proportions produce a transparent glaze or glass, but where that is not desired
I prefer to employ more soda. The workman will readily ascertain when the
above process is completed, by taking a small quantity of the mixture from the
furnace and tasting it when cool, and if he finds that it offers a sweetness to
the taste, and not an alkaline flavour, the preparation is complete.
In the manufacture of glass I employ the purified borate of a lime as a
substitute for borax in such proportion that the quantity of boracic acid always
remains the same in the manufacture of flint, plate, crown, and sheet glass;
but the crude borate as imported reduced to powder is sufficiently pure for
pale glass, such as is employed in making medicinal bottles and other like
descriptions of glass. In such application where lime and soda are usually em-
ployed as constituents of the glass, it is unnecessary to resort to the preliminary
process of fritting; and I may remark, where parties prefer to do so, sulphate
of soda may be substituted for the carbonate, in the proportion of seventy-two
of the former for fifty-four of the latter, where phosphate of soda has here-

page_text: tofore been used in the manufacture of a glass. I do not in such cases recom-
mend the use of borate of lime.
Having thus described the nature of my Invention, I would have it under-
stood that what I claim is, the application of native borate of lime alone, or
fritted with a salt of soda, in the preparation of glaze for clay wares. I also
claim the application of native borate of lime alone, or fritted with a salt of
soda, in the manufacture of glass.
In witness whereof, I, the said Thomas Richardson, have hereunto set
my hand and seal, this Tenth day of April, in the year of our Lord
One thousand eight hundred and fifty-six.
Witness,
WILL. CHUTER, Sol",
Newcastle, Tyne.
THOMAS RICHARDSON. (L.S.),