IMPROVEMENTS IN THE MANUFACTURE OR GLAGO
Year: 1852

page_text: LETTERS PATENT to John Thomas Way, of Holles Street, Caven-
dish Square, in the County of Middlesex, Professor of Chemistry,
and John Manwaring Paine, of Farnham, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OR GLAGO »
Sealed the 2nd February 1853, and dated the 11th December 1852.
PROVISIONAL SPECIFICATION left by the said John Thomas Way
and John Manwaring Paine at the Office of the Commissioners
of Patents, with their Petition, on the 11th December 1852.
We, JOHN THOMAS WAY, of Holles Street, Cavendish Square, in
the County of Middlesex, Professor of Chemistry, and JOHN MAN-
WARING PAINE, of Farnham, in the County of Surrey, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF GLASS" to be as follows:-
This Invention consists of applying, in the manufacture of glass, a
stone or clay found in Surrey (and which will probably be found
in other parts), which is composed largely of soluble silica, and also

page_text: in employing soluble silica in obtaining the materials (or some of
them) for glass making in a state of silicate, before subjecting them
to fusion.
SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said John Thomas Way and John
Manwaring Paine in the Great Seal Patent Office on the 10th
June 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, wc,
JOHN THOMAS WAY, of Holles Street, Cavendish Square, in the
County of Middlesex, Professor of Chemistry, and JOHN MAN-
WARING PAINE, of Farnham, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of December, in the
year of our Lord One thousand eight hundred and fifty-two, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said John Thomas Way and John
Manwaring Paine, Her special licence that we, the said John
Thomas Way and John Manwaring Paine, our executors, adminis-
trators, and assigns, or such others as we, the said John Thomas
Way and John Manwaring Paine, our 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 ex-
pressed, 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," upon the condition (amongst others)
that we, the said John Thomas Way and John Manwaring Paine,
or one of us, by an instrument in writing under our hands and
scals, or under the hand and seal of one of us, 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.

page_text: NOW KNOW YE, that we, the said John Thomas Way and
John Manwaring Paine, do hereby declare the nature of the said
Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following
statement thereof (that is to say):
This Invention consists of applying, in the manufacture of glass,
a stone or clay formed in Surrey (and which will probably be found
in other parts), which is composed largely of soluble silica, and also
in employing soluble silica in obtaining the materials (or some of
them) for glass making, in a state of silicate, before subjecting them
to fusion; but, before we proceed to describe the nature of our
said improvements, we will, for the better understanding thereof,
state what we mean by "soluble silica."
By this term we intend to specify that peculiar form or condition
of silica or silex which is found to be readily soluble in solutions of
caustic potash or soda, when boiled with these solutions in open
vessels. This kind of silica is, when artificially prepared, obtained
by adding to solutions of silicate of potash or soda a mineral or
other acid, by which the silica is precipitated in the " gelatinous
state." This soluble or gelatinous silica differs from the silica of
sand, flint, or quartzrock, inasmuch as these last named substances
are not practically soluble in solutions of potash or soda, when boiled
with these solutions in open vessels, and can only be dissolved by
them when inclosed in vessels fitted with steam tight covers, by
which pressure and a much higher temperature are obtained.
We may here state, that we have discovered at the base of the
Chalk Hills in Surrey, and it will probably be found elsewhere, a
stone or clay which contains silica in the soluble state in large
quantity, in some cases amounting to as much as seventy per cent.
of the dry stone or clay; and one part of our Inventions consists
in applying this stone or clay as a source of soluble silica for the
manufacture of glass in the way to be hereafter described.
Such minerals are easily recognized by reducing them to fine
powder, boiling the powder in caustic soda, and afterwards adding

page_text: to the solution formed an excess of hydrocholoric acid which pre-
cipitates the silica.
To produce glass of different kinds, and applicable to different
purposes, it is necessary, as is well known, to vary the quantity of
the inaterials which are employed; but as our Invention does not
consist in any modification of the proportion of these materials, but
rather in the manner of preparing and combining then, we think
it necessary to describe in detail these particulars, which are other-
wise well known.
The first part of our Invention consists in obtaining a silicate of
potash or soda from substances containing soluble silica, and we
have found that two methods can be advantageously employed for
this
purpose. The first of these consists in mixing the rock clay,
or mineral containing the soluble silica, previously reduced to fine
powder, as is well understood, with the requisite quantity of car-
bonate of soda or potash, or of their alkalies, in the caustic state.
The mixture is then introduced into a reverberatory furnace, or
other suitable arrangement, and heated to a gentle low red heat.
We have found that soluble silica can be made to decompose the
alkaline carbonates forming silicates at a much lower temperature
than is necessary for the combination of these alkalies with sand,
powdered flint, or other form of silica; and we are careful in this
operation to keep the heat as low as possible, consistently with the
combination of the materials, so that fusion of the product may be
avoided.
The result of this process is soluble silicate of potash or soda,
with more or less of impurities, according to the nature of the
substances employed. From this product the silicate of soda or
potash is dissolved out by water, or by a solution of caustic alkali,
and applied to the manufacture of glass in the manner to be pre-
sently described.
Our second method is obtaining silicate of potash or soda from
substances containing soluble silica, and to dissolve out the silica by
caustic alkali, with or without the aid of heat; the last, however,
being the method of dissolving which we prefer.
Both in this and

page_text: the preceding process we are careful to use as small a quantity of
water as possible, in order to diminish the cost of subsequent eva-
poration, which has to be performed before the materials can be
fused for glass.
Having obtained, by either of the methods now described, an
alkaline silicate in solution, we mix with this solution, previously
concentrated to any desirable density, if required, the requisite
quantity of lime, and of oxide of lead, or of other alkaline earths or
metallic oxides which are employed for the production of the
different kinds of glass, and by means of heat, and with sufficient
stirring of the materials to keep them in uniform mixture, we reduce
the whole to a dry state. The product may, if necessary, be more
uniformly mixed by grinding to powder by any suitable mechanical
means. We prefer to employ the earth, lime, and the oxide of lead
or other metallic oxide, in the state of caustic lime, slacked or un-
slacked, and of oxide of lead itself, rather than in the state of
carbonates or other salts; because the different silicates of lime,
lead, &c, are then in great part, or entirely, produced in the act of
drying the materials. But in some cases carbonates or other salts
of these bases may be employed with advantage. The materials
prepared as described are now introduced into the glass pots ordi-
narily employed in the melting of glass, and heated in the usual
way;
but we find that, from the circumstances of the combination
being already in great part or altogether effected, the temperature
duration of the firing are not required to be by any means so great
as in ordinary glass making, and the resulting is of a much more
uniform character. We have not thought it necessary to give a
detailed account of the quantities of the different materials to be
employed, because the manufacturer will vary these at pleasure,
according to the result which is desired; but we may state that,
having selected for his source of soluble silica a substance containing
as high a proportion of silica as possible, he will employ, in the pro-
duction of soluble silica, such a quantity of it as will give him the
quantity of silica necessary, not only for the potash or soda employed,
but also for the lime, oxide of lead, &c., afterwards to be added.

page_text: We have found it easy to dissolve, by a solution of caustic soda of a
density of 1-29 and containing nineteen per cent. of real alkali, as
much as two chemical equivalents of silica for every equivalent of
alkali employed, or about three parts by weight of silica for every
one part of soda; but, by continued boiling and by regulating the
strength of the liquid, as much as four times its weight of silicate
may be dissolved by the alkali.
In some cases we find it desirable to dissolve only a smaller
quantity of silica than those above mentioned, and to combine the
lime oxide of lead separately with silica, by boiling them with a
requisite quantity of alkaline silicate, and separating them from the
solution of caustic soda, or potash formned. These silicates are then
mixed with the solution of silicate of soda or potash, and evaporated
as before described.
We claim as our Invention the application of soluble silica, or of
substances containing it, in the manufacture of glass.
We also claim the use of soluble alkaline silicates, in mixture or
combination with different earths and metallic oxides, for the pro-
duction in great part, or entirely, of the silicates, of which glass
consists, previously to their fusion in the glass pots.
In witness whereof, I, the said John Manwaring Paine, have
hereunto set my hand and seal, this Tenth day of June, in
the year of our Lord One thousand eight hundred and fifty-
three.
Witness,
S. CARPMAEL.
J. M. PAINE. (L.S.)