IMPROVE- MENTS IN THE MANUFACTURE OF BURNED AND FIRED WARE
Year: 1852

page_text: LETTERS PATENT to John Thomas Way, of Holles Street,
Cavendish Square, in the County of Middlesex, Professor of
Chemistry, and John Manwaring Paine, of Farnham, in the
County of Surrey, Gentleman, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF BURNED AND FIRED WARE."
Sealed the 17th January 1853, and dated the 17th November 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 17th November 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, Gentleman, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF BURNED AND FIRED WARE" to be as follows:-
This Invention consists of applying a stone or clay, found in
Surrey, and which will probably be found in other parts, and which
is composed largely of soluble silica, in these manufactures, and also
of combining clay, lime, and other materials with reference to the
quantity of soluble silica present (whether naturally or artificially
obtained), which we have found to be capable of varying the
character of the burned and fired ware produced.

page_text: 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 17th May 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
THOMAS WAY, of Holles Street, Cavendish Square, in the County
of Middlesex, Professor of Chemistry, and JOHN MANWARING PAINE,
of Farnham, in the County of Surrey, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the seventeenth day of November, 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 Mainwaring Paine, Her special licence that we, the said John
Thomas Way and John Mainwaring Paine, our executors, ad
ministrators, and assigns, or such others as we, the said John Thomas
Way and John Mainwaring 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 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 BURNED AND FIRED WARE," upon the condition (amongst others) that
we, the said John Thomas Way and John Mainwaring Paine, or one
of us, by an instrument in writing under our hands and seals, or under
the hand and seal of one of us, should particularly describe and as
certain 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 we, the said John Thoinas Way and John
Mainwaring 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 thereo
(that is to sax)·

page_text: These improvements consist of applying a stone or clay (found
in Surrey, and which will probably be found in other parts), which
is composed largely of soluble silica, in these manufactures, and also
of combining clay-lime and other materials with reference to the
quantity of soluble silica present (whether naturally or artificially ob-
tained), which we have found to be capable of varying the character
of burned and fired ware produced.
us.
And in order that our said Invention may be more fully
understood, we will proceed to describe the means pursued by
We employ the earth silica in the condition known to
chemists as soluble silica or gelatinous silica, and the natural
earths, beds, or strata containing silica in the same soluble state,
to mix with ordinary or prepared clays, and with or without
lime or other alkaline earths and bases, in various proportions
according to the particular object in view, for the production, when
burnt, of bricks, artificial stone, pottery, porcelain, and such like
articles.
But before we proceed farther to describe our Invention, we
will, for the better understanding thereof, describe what we mean
by. "soluble" or "gelatinous" 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 sodu,
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 inineral or other acid, by which the
This soluble
silica is precipitated in the "gelatinous" state.
or gelatinous silica differs from the silica of sand, flint, or
quartz rock, 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 so dissolved by
then when enclosed in vessels fitted with steam-tight covers, by
which pressure and a much higher temperature is obtained.
Having explained what we mean by soluble or gelatinous silica,
we now proceed to state that we have discovered that certain beds or
strata of earth, as the base of the chalk hills occurring in parts of

page_text: Surrey and elsewhere, contain large proportions of silica; in this
soluble condition such minerals are easily recognized by reducing
them to fine powder, boiling the powder in caustic soda, and after-
wards adding to the solution formed an excess of hydrochloric acid,
which precipitates the silica. The silica thus obtained should
amount to at least ten per cent. of the weight of the original mineral,
and one part of our Invention consists in using the earth of these
beds, either separately or in admixture with each other, or with clay,
in such proportions, and with or without lime or other alkali or alka-
line earth, as may be required for the production of different kinds
of burnt wares.
We will here observe, that we produce the different kinds of
burnt wares by a proper adjustment of the quantity of soluble silica
in relation to the composition of the clay with which it is mixed,
and by a
a greater or less temperature and length of time in the
burning. And in order that these matters may be fully understood,
we will describe our method of producing several kinds of materials
for building purposes.
To produce a superior kind of plain or ornamental brick or tile
or slabs suitable for the lining of walls, we proceed as follows:
Having ascertained by chemical examination the proportion of
soluble silica contained in different samples of the earth in question,
we reduce such earths to powder by mechanical means, as is well
understood. We find fifteen to thirty per cent. of soluble silica to
be the most suitable for the purposes mentioned when using the
earth alone; or we mix the requisite quantity of the earth con-
taining a higher per-centage than those given above of soluble silica,
with ordinary clay, in such relative quantities that the mixture shall
contain the proportion of soluble silica above stated.
Having prepared the materials by either of the above methods,
we proceed to mould the bricks or other articles, either by pressure
or in the ordinary way. When pressure is employed, we find it
desirable to use the materials in a slightly damp state, but not so
much so as is usual in the making of bricks from clay. In fact,
we prefer to use the materials as dry as may be, having reference to

page_text: the mode of moulding resorted to. The bricks, or other articles,
being moulded, are to be dried in the air or in drying chambers,
and are then to be burned in the usual way in suitable kilns. The
degree of heat, however, and the length of time occupied in the
burning, materially affect the character of the article produced. For
instance, a gentle burning produces a material comparatively soft
and capable of being sawn, cut, or planed like stone or wood; it is
therefore sometimes desirable to stop the burning at this point, and
to give to the articles, by the use of tools, a higher degree of finish
and sharpness than is possible by the method of moulding before de-
scribed. And the goods, when so worked up, may be a second time
heated and carried, by an increased temperature and duration of the
firing, to a much greater degree of hardness and strength. And
with a sufficiently elevated temperature the material may be made
of extreme hardness, so as to be capable of taking a high polish like
granite. In this latter form we propose to employ it in the manu-
facture of mantle-pieces, table-tops, and other articles requiring such
degree of hardness.
We have stated that, for the manufacture of moulded articles, we
employ a mixture in which the proportion of soluble silica varies
from fifteen to thirty per cent.; when it is intended that the material
produced should be employed as stone, and be cut or tooled, it is
desirable to employ a larger proportion of soluble silica, which is
found to render the product more granular and open in texture.
The same is the case when bricks are intended for the building of
furnaces, kilns, and in other cases where they will be exposed to a
high temperature; and we find that in making fire-bricks the pro-
portion of soluble silica may with advantage be as high as from
thirty-five to forty-five per cent. ; but it is to be observed that, when
present in above a certain proportion, the silica destroys the ductility.
of the mixture, which cannot then be moulded by hand as ordinary
clay, but must be subjected to pressure.
We have hitherto spoken only of the mixtures of the dif-
ferent earths containing soluble silica, with each other, or with
ordinary clay. But we find that a different, and for many

page_text: purposes very valuable kind of material is obtained by mixing
with these ingredients a certain proportion of lime or other
alkali or alkaline earth; thus, to produce a yellowish white or
lemon-coloured stone, in imitation of the best building-stones, we
employ a mixture of earths as before described, in which the soluble
silica is in the proportion of from thirty-five to forty-five per cent.
with eight or ten per cent. of lime. The mixture may be moulded
by hand or pressed into moulds as before described (the latter being
the preferable method), and afterwards dried and burned. We
employ lime in the state either of burnt lime, slaked or unslaked, or
in the state of carbonate of lime or chalk. We have found that the
mixture, when made with slaked lime, gives the best results; but in
some cases chalk may be advantageously employed, as being the most
economical.
We have found that, by varying the proportions of soluble silica
and of lime in relation to the clay, we are enabled to produce
different kinds of stone, more or less resembling natural stone, fitted
for building and other purposes, and this stone is capable of being
cut with tools after being fired. We have also found, that the
addition of a small proportion of lime to a mixture containing a high
per-centage of soluble silica, produces a good fire-brick.
We claim as of our Invention the use of natural earths, mineral
beds or strata, which contain soluble silica in considerable quantities,
and the admixture of these earths (or of soluble silica itself) in dif-
ferent proportions with clay, and with or without the addition of
lime or other alkalies, for the production, when burned, of bricks,
tiles, pipes, fire-bricks, and of artificial stone suitable for building,
paving, and ornamental purposes, and for the filtration of water
and applicable to various other useful purposes.
We also claim the use of "soluble silica," or of earths containing
it, in the manufacture of different kinds of porcelain, as a substitute
for the powdered flint or other insoluble silica at present employed
in these manufactures. We do not, however, claim any novelty in
the mechanical means employed for mixing the materials, or in the
modes of moulding, shaping, or burning the same. Neither do wė

page_text: claim the use of sand, powdered flint, or other form of silica, other
than that form described by us as "soluble silica."
In witness whereof, I, the said John Thomas Way, have hereunto
set my hand and seal, this seventeenth day of May, in the year of
our Lord One thousand eight hundred and fifty-three.
Witness,
JN° ALCOCK.
J. THOMAS WAY. (L.S.)