IMPROVEMENTS IN THE MANUFACTURE OF FIRE-BRICKS, TILES, AND SOLID OR HOLLOW FIRE-LUMPS; AND IN THE MANUFACTURE OF RETORTS, PIPES, CRUCIBLES, OR OTHER HOLLOW VESSELS OR MOULDS REQUIRED TO RESIST A HIGH DEGREE OF HEAT; AND ALSO IN THE MANUFACTURE OF ORNAMENTAL BRICKS, TILES, QUARRIES, TRUSSES, BOSSES, VASES, BUSTS, FIGURES, COLUMNS, CAPITALS, BASES, CORNICES, COPINGS, TABLETS, FINIALS, AND OTHER ARTICLES OF AN ORNAMENTAL CHARACTER EMPLOYED IN BUILDING AND IN ARCHITECTURAL DECORATIONS." PROVISIONAL SPECIFICATION
Year: 1867

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, Cannon
Street, in the City of London, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF FIRE-BRICKS, TILES, AND SOLID OR HOLLOW FIRE-LUMPS;
AND IN THE MANUFACTURE OF RETORTS, PIPES, CRUCIBLES, OR OTHER HOLLOW
VESSELS OR MOULDS REQUIRED TO RESIST A HIGH DEGREE OF HEAT; AND ALSO
IN THE MANUFACTURE OF ORNAMENTAL BRICKS, TILES, QUARRIES, TRUSSES,
BOSSES, VASES, BUSTS, FIGURES, COLUMNS, CAPITALS, BASES, CORNICES,
COPINGS, TABLETS, FINIALS, AND OTHER ARTICLES OF AN ORNAMENTAL
CHARACTER EMPLOYED IN BUILDING AND IN ARCHITECTURAL DECORATIONS."
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents; with his Petition, on the 9th
December 1867.
I, HENRY BESSEMER, of Queen Street Place, Cannon Street, in the City of
London, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF FIRE-BRICKS, TILES, AND SOLID OR HOLLOW FIRE-LUMPS;
AND IN THE MANUFACTURE OF RETORTS, PIPES, CRUCIBLES, OR OTHER HOLLOW
VESSELS OR MOULDS REQUIRED TO RESIST A HIGH DEGREE OF HEAT; AND ALSO IN
THE MANUFACTURE OF ORNAMENTAL BRICKS, TILES, QUARRIES, TRUSSES, BOSSES,
VASES, BUSTS, FIGURES, COLUMNS, CAPITALS, BASES, CORNICES, COPINGS, TABLETS,.
FINIALS, AND OTHER ARTICLES OF AN ORNAMENTAL CHARACTER EMPLOYED IN
BUILDING AND IN ARCHITECTURAL DECORATIONS," to be as follows:-
In the manufacture of terra cotta and other articles of plastic clay as at
present practised the amount of shrinking which the material undergoes during

page_text: the process of drying, and also in kiln where it is "burned," produces not only
a reduction in size, but in many cases a great distortion of the form originally
given to the material, and not unfrequently produces cracks which materially
lessen or destroy the value of the article produced. The length of time
occupied in the drying and firing of articles made of plastic clay is also in many
cases a serious disadvantage. Now, therefore, the object of my Invention is
the production of various articles in clay or in such mixtures of clay with other
substances as are commonly employed in the manufacture of fire-bricks and
in terra cotta and other pottery in such. manner that little or no shrinking or
distortion of the article shall take place during its manufacture, while the time
occupied in its production is considerably reduced. For this purpose I employ
clay (or a mixture of clay with other materials) that has previously been
subjected to a red heat, and has thereby to a great extent lost its plastic
qualities and power of sbrinking.
In the manufacture of fire-bricks and like articles I prefer to use the old
broken fire-bricks or bats that have previously been employed in constructing
furnaces, or in lieu thereof I burn lumps of raw fire-clay either in kilns or in
open heaps in the way generally employed in burning "ballast," so also when
manufacturing ornamental objects to be used for architectural or other
purposes I employ either of the several descriptions of broken or refuse
pottery or burned pipe clay, or potters' clay, or mixtures thereof with other
materials such as are readily obtained from potteries or may be collected
elsewhere; or in lieu thereof I burn such potters' clay or mixed materials in
kilns or heaps as before mentioned. I next proceed to crush the burned
lumps of clay or broken bricks or pottery in any suitable crushing machine,
preferring however for that purpose a machine for which Letters Patent were
granted to John Henry Johnson, dated the 14th day of June 1858 (No. 1846),
the more perfect pulverizing or granulating of the materials being effected
between rolls or under edge rúnners, after which the material is to be separated
into various degrees of fineness (by sieves or otherwise) suitable for producing
the particular grain or quality desired in the various articles to be manu-
factured therefrom. The tint of color may be varied by the admixture of
natural or artificially colored clays, or by the employment of metallic oxides,
or by other known substances mixed with the powdered clay or with the clay
while in a plastic state before burning and reducing it to a powdered or
granular state. The fine granular burned clay thus prepared is put into a pug
mill or mixing cylinder, and as much silicate of soda or potash having the
consistency of thick treacle is added thereto as will when mixed with the dry
clay reduce the same to a sticky or moist condition, somewhat resembling

page_text: Muscavado sugar. The admixture of the silicate will be facilitated if the clay
powder be previously moistened with a little water; the mixture may be
moulded in the same way as moulders' sand is used by founders, and. when
taken from the mould (or sometimes while retained there), the article is to be
sprinkled with a saturated solution of chloride of calcium or other soluble salt
eontaining a base which will combine with the silica and form an. insoluble
eompound, and if necessary boiled in such solution, after which the chloride
of sodium formed by the chemical action of the two fluids may be removed by
the solvent action of a plentiful supply of fresh water, after which the drying
may take place in open sheds or in a drying room; and although I have here
shown how the fine pulverized clay may be moulded by hand and the chloride
of calcium and water made to gradually permeate the mass; I nevertheless
desire it to be understood that I prefer to employ a partial vacuum to assist in
moulding, saturating, washing, and drying articles moulded in pulverized
burned clay, after the manner set forth in the Provisional Specification of a
previous Invention for the manufacture of silicious stone, for which Provisional
Protection was granted to me, and to Frederick Ransome, and Ernest Leslie,
Ransome, bearing date the 11th day of November last (No. 3193).
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Bessemer in the Great Seal Patent Office on the
9th June 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, Cannon Street, in the City of London, seud
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of December, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Henry Bessemer, Her special licence that I, the said Henry Bessemer, my
executors, administrators, and assigns, or such others as I, the said Henry
Bessemer, 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 "IMPROVE-
MENTS IN THE MANUFACTURE OF FIRE-BRICKS, TILES, AND SOLID OR HOLLOW FIRE,

page_text: LUMPS; AND IN THE MANUFACTURE OF RETORTS, PIPES, CRUCIBLES, OR OTHER
HOLLOW VESSELS OR MOULDS REQUIRED TO RESIST A HIGH DEGREE OF HEAT; AND
ALSO IN THE MANUFACTURE OF ORNAMENTAL BRICKS, TILES, QUARRIES, TRUSSES,
BOSSES, VASES, BUSTS, FIGURES, COLUMNS, CAPITALS, BASES, CORNICES, COPINGS,
TABLETS, FINIALS, AND OTHER ARTICLES OF AN ORNAMENTAL CHARACTER EMPLOYED
IN BUILDING AND IN ARCHITECTURAL DECORATIONS," upon the condition (amongst
others) that
the said Henry Bessemer, 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 Inven-
tion, 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 Henry Bessemer, 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:-
In the manufacture of terra cotta and other articles of plastic clay as at
present practised the amount of shrinking which the material undergoes
during the process of drying, and also in kilns where it is "burned," produces
not only a reduction in size, but in many cases a great distortion of the form
originally given to the material, and not unfrequently produces cracks, which
materially lessen or destroy the value of the article produced. The length of
time occupied in the drying and firing of articles made of plastic clay is also
in many cases a serious disadvantage. Now, therefore, the object of my
Invention is the production of various articles in clay or in such mixtures of
clay with other substances as are commonly employed in the manufacture of
fire-bricks and in terra cotta and other pottery in such manner that. little or
no shrinking or distortion of the article shall take place during its manu-
facture, while the time occupied in its production is considerably reduced. For
this purpose I employ clay (or a mixture of clay with other materials) that
has previously been subjected to a red heat, and has thereby to a great extent
lost its plastic qualities and power of shrinking; the burned clay so employed
may, however, in some cases be mixed with a small portion of plastic clay in
a dry and powdered state, by preference not exceeding one-sixth to one-tenth
the weight of the burned clay used in conjunction therewith.
In the manufacture of fire-bricks and like articles I prefer to use the old
broken fire-bricks or bats that have previously been employed in constructing
furnaces, or in lieu thereof I burn lumps of raw fire-clay either in kilns or in
open heaps in the way generally employed in burning "ballast," so also when

page_text: manufacturing ornamental objects to be used for architectural or other
purposes, I employ either of the several descriptions of broken or refuse
pottery, or burned pipe clay, or potter's clay, or mixtures thereof with other
material, such as are readily obtained from potteries, or may be collected
elsewhere, or in lieu thereof. I burn such potter's clay or mixed materials in
kilns or heaps as before mentioned. I next proceed to crush the burned lumps
of clay, or broken bricks, or pottery, in any suitable crushing machine,
preferring, however, for that purpose a machine for which Letters Patent
were granted to John Henry Johnson, dated the 14th day of June, 1858,
(No. 1346), the more perfect pulverizing or granulating of the materials.
being effected between rolls or under edge runners, after which the material is.
to be separated into various degrees of fineness (by sieves or otherwise)
suitable for producing the particular grain or quality desired in the various,
articles to be manufactured therefrom when the article to be made is intended.
to be subjected while in use to frequent changes of temperature (and wher
porosity is not objectionable), I prefer to use the granulated clay in a coarse-
state, the grains being about the size of the coarser description of Thames
sand, but for purposes where a more dense material is required the burned.
clay may be employed in a much more minute state of division. In the.
employment of such materials for the manufacture of fire-bricks, fire-tiles &c.,.
it is not so much sought to obtain an article of a very highly refractory.
character as to facilitate the production of such fire-bricks, fire-lumps, &c. as:
require to be specially moulded; and to lessen the time required and the:
shrinking and distortion so objectionable in large pieces of moulded clay as at.
present manufactured. When ornamental objects are to be made the tint of
color may be varied by the admixture of natural or artificially colored clays:
or by the employment of metallic oxides, or by other known substances mixed.
with the powdered clay or with the clay while in a plastic state before burning;
and reducing it to a powdered or granular state. The fine granular burned
clay thus prepared is put into a pug mill or mixing cylinder, and as much,
silicate of soda or potash having the consistency of thick treacle is added,
thereto as will when mixed with the dry clay reduce the same to a sticky or,
moist condition somewhat resembling Muscavado sugar; the admixture of the
silicate will be facilitated if the clay powder be previously moistened with a
little water. The mixture thus formed of fluid silicate and granulated clay.
should be well and evenly rammed into every part of the mould by a suitable
rammer, or it may be forced therein by a press; in either case sufficient.
pressure should be employed to render the object moulded sufficiently firm to
bear its removal from the mould without injury. The moulds may be made
"

page_text: of metal, plaster of Paris, or wood, and the moulded article when taken from
the mould (or sometimes while retained there) is to be sprinked and well
soaked with a saturated solution of chloride of calcium or other soluble salt
containing a base which will combine with the silica and form an insoluble
compound, and, if necessary, the moulded article may be boiled in such
solution, and after it is completely saturated with the chloride of calcium it
should by preference be allowed to remain in a dry place for 12 or 24 hours in
order that the gelatinous silicate of lime formed in the interstices between the
grains of burned clay may harden and cement the whole firmly together, after
which the chloride of sodium formed by the chemical action and union of the
silicate of soda and chloride of calcium may be removed by the solvent action
of a plentiful supply of fresh water allowed to fall on to it like a heavy shower
of rain for a period of 12 to 36 hours, depending on the thickness and
porosity of the article, after which the drying may take place in open sheds or
in a drying room, and although I have shown how the fine pulverized clay
may be moulded by hand and the chloride of calcium and water made to.
gradually permeate the mass, I nevertheless desire it to be understood that I
prefer to employ a partial vacuum to assist in moulding, saturating, washing,
and drying articles moulded in pulverized burned clay after the manner set
forth in the Specification of a previous Invention for the manufacture of
siliceous stone, for which Letters Patent were granted to me and to Frederick
Ransome and Ernest Leslie Ransome, bearing date the 11th day of November
last (No. 3198). The silicate of soda herein-before referred to may for the
purposes
Invention be made by subjecting flints (such as are obtained
from the chalk formation) to the action of a saturated solution of caustic soda
in an iron boiler under a pressure of steam equal to 60 or 80 lbs. per square
inch, the solution being afterwards concentrated in an open steam pan as
already practised, and which mode of producing silicates I lay no claim to.
of my
Having described my Invention, and the manner in which the same may be
carried into practical operation, I desire it to be understood that I do not
confine myself to the precise details herein given, provided the essential parts
of my said improvements be retained; but what I claim is,-
Firstly. The manufacture of fire-bricks, tiles, and solid or hollow fire-
lumps, retorts, pipes, crucibles, and other hollow vessels or moulds required to
resist heat by moulding or forming such articles in granulated burned clay
or in a mixture of clay and other materials that have previously been subjected
to a red heat, and causing such granulated materials to cohere by the employ-
ment of a soluble silicate acted on by chloride of calcium in the manner
herein-before described.

page_text: Secondly. I claim the manufacture of ornamental brisks, tiles, quarries,
trusses, bosses, vases, busts, figures, columns, capitals, bases, cornices, copings,
tablets, finials, and other articles of similar character employed in building
and architectural decorations, by moulding or forming such articles in
granulated burned clay or in a mixture of clay and other materials that have
previously been subjected to a red heat, and causing such granulated
materials to cohere by the employment of a soluble silicate acted on by
chloride of calcium in the manner herein-before described.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Ninth day of June, in the year of our Lord One
thousand eight hundred and sixty-eight.