IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF SLAG AND VITREOUS SUBSTANCES, AND THE COMBINATION OF OTHER SUBSTANCES THEREWITH
Year: 1854

page_text: LETTERS PATENT to William Henry Smith, M.D., of Philadelphia, in
the United States of America, Henry Bessciner, of Baxter House, St.
Pancras, and Robert Longsdon, of Hornsey Lane, Engineers, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF
SLAG AND VITREOUS SUBSTANCES, AND THE COMBINATION OF OTHER SUBSTANCES
THEREWITH."
Sealed the 12th January 1855, and dated the 21st August 1854.
PROVISIONAL SPECIFICATION left by the said William Henry Smith,
Henry Bessemer, and Robert Longsdon at the Office of the Commis-
sioners of Patents, with their Petition, on the 21st August 1854.
We, WILLIAM HENRY SMITH, M.D., of Philadelphia, in the United States
of America, HENRY BESSEMER, of Baxter House, St. Pancras, and ROBERT
LONGSDON, of Hornsey Lane, Engineers, do hereby declare the nature of the
Invention for "IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF SLAG AND
VITREOUS SUBSTANCES, AND THE COMBINATION OF OTHER SUBSTANCES THERE WITH,"
to be as follows:-
These improvements relate chiefly to the manufacture and treatment of the
vitrified substances or "slags" produced in the process of smelting iron and
other metals. The fluid matter which flows from the smelting furnaces is con-
ducted by a gutter, which may be formed of fire clay, and covered with the
same material, instead of throwing asbes on the running slag, as at present
A

page_text: practised. The gutter may be also formed with an, outer flue surrounding it,
into which flue a small blast of-hot air or flame is conducted.
prevent the slag from cooling and becoming fixed in the gutter.
This would
By the above channel the fluid "slag" is run into any one of a series
of vessels formed of fire clay, which are placed in a suitable furnace; we pre-
ferring the circular arrangement described in a Patent granted to the said
Henry Bessemer, for improvements in the manufacture of. glass, and bearing
date the Twenty-second day of March; One thousand eight hundred and forty-
eight. In this arrangement the pots are heated by a fire placed central with
the series of pots or vessels. If found desirable, the heat of the slag may be
here increased; or if found sufficient, it may remain in a quiet state until the
gaseous matters have escaped, and any light impurities are floated up to the
surface, and others of a greater-weight have subsided; after which the pot is
to be removed from the furnace, and its contents poured into moulds of the
required form..
A great inconvenience has hitherto been found to arise from the solidifica-
tion of a portion of the slag on the interior surface of the cars or pouring
vessels by which the slag has been brought to the moulds, in consequence of
the absorption of heat by the said vessels; by the use of clay pots heated to
redness in the furnace before referred to, this inconvenience is prevented, and
a proper refinement of the slag is obtained. As the slag in running from the
furnace varies continually in quality and color, it is therefore desirable as far
as possible to counteract the effect of these changes, by the admixture of
either coloring matter or other materials, to render it suitable to the peculiar
purpose required.
...
If it is only. desired to alter or modify the color of the slag, metallic oxides,
alone or mixed with an alkaline salt, are to be added during the filling of the
pot, and be well incorporated by stirring; but in some cases we entirely alter
the quality of the slag. This change in the composition of the slag we effect
by the admixture of dry pulverulent matters capable of combining with the
fluid slag.
Well-burnt clay reduced to powder, slacked lime, sand, or other mineral
substances may be used in such quantities as will not render the slag too solid
for working. In all cases these matters are to be heated to redness before
mixing with the melted slag, and a thorough combination of them is to be
effected by stirring. When it is desired to give the manufactured articles a
'mottled appearance; we mix with the fluid slag small fragments of other
slags, or broken glass of various colors or qualities, which will become fused or
only partially so, according to the time they are left in the furnace.

page_text: The combination of other materials with slag, in order to modify its quality
or color, having been effected in the manner described, we in some cases com-
bine it with iron in the formation of table tops, mantle pieces, or other articles.
For this purpose the iron portion of the article is pickled in dilute sulphuric
acid and well cleaned; it is then made hot in a suitable oven, then to be
immersed in the fluid slag. As soon as a complete adhesion of the slag is
effected, the article is taken out and held vertically over the bath or vessel
until all superfluous portions drain off; it is then to be removed to the anneal-
ing oven, where its temperature is to be slowly reduced. As soon as it has
become cold, the compound article may have its surface ground and polished,
in the manner herein-after described.
We have herein-before shewn how the action of additional heat to the
materials in the pots will render it more fluid and easy to refine'; but it must
be observed that this fluid condition is not suited to the working of the slag
by the processes of rolling on a table, blowing, or pressing in moulds. Wo
therefore allow the furnace to cool down until the vitreous matter in the
pots has assumed that plastic condition most favorable for these operations.
The slag having been treated by any of the methods herein set forth, and
being in its purified or refined condition, is to be removed when at a suitable
temperature in its pot from the furnace, and the semi-fluid matters poured
therefrom into the moulds by tilting the pot, and immediately the pot is
emptied it is to be returned to the furnace to be recharged with slag.
When ornamental tiles or slabs of slag are required to be veined, somewhat
similar in appearance to marble, we pour the contents of two or more vessels
in a united stream into the moulds or on to the casting table, the contents of
each vessel being of a different color.
Having thus prepared the slag of suitable color and quality, we have found
that in addition to a specific quality for special purposes, that it is equally
necessary to alter the construction of the mould employed, in order to produce
the required articles at the most economical rate, and therefore the moulds to
be used for different articles of slag we construct in the following manner :-
For statuary, columns, or architectural or other floral designs, we mould the
object in moist sand or dry loam, in suitable iron "flasks" or boxes; or we
make a mould composed of plaster of Paris mixed with brick dust, ashes, or
other matters capable of rendering the mould more porous and less liable to
break by heat. The mould used for casting tiles or similar small articles we
mould in sand, by forming a long hollow trough, which we divide into suitable
spaces, by inserting therein thin sheet-iron partitions.
For tessala, or other small articles requiring to be very rapidly and cheaply

page_text: moulded, on account of being made in great number, we would employ a
machine described in a Patent granted to the said Henry Bessemer for
improvements in the manufacture of glass, dated the Twenty-second day of
March, One thousand eight hundred and forty-eight, and in which machine
the moulds are formed by being sunk on the edges of a pair of wheels, which
revolve in contact, and by their action press the slag into the forms indented on
their surfaces.
We would also claim the use of the casting table, described in a Patent
granted to the said Henry Bessemer, dated the Thirty-first January, One
thousand eight hundred and forty-nine, as applied to the manufacture of slag;
the table being formed of small iron squares fixed by bolts to an under
plate, which is hung on a centre so as to allow the table to assume an inclined
position, which greatly facilitates the removal of the slab or plate (that has
been cast and rolled) into the annealing oven, the floor of which we place at
an angle to suit the inclination of the table.
..
For producing flat slabs or tiles having mouldings or figured designs on one
side of them, we use a long box or tray of metal filled with sand. The tray is
mounted on wheels, and is caused to move beneath a roller having on it the
required design in relief, which is impressed in the sand as it moves beneath
the roller; metal frames are then laid upon the sand, and open castings made
therein; or in lieu of this a plain or figured slab of granite is used to form the
hed on which the moulds are laid.
For hollow articles, such as drain pipes, columns, &c., having a plain,
circular, or polygonal section, we construct a metal mould, truly bored or
plane, and of a slightly conical form, of which shape the core is also to
partake. The mould thus composed is fitted to a suitable frame, so arranged
that the core may be counterbalanced, and made to slide out quickly imme-
diately that the tube or other article is sufficiently hardened. A sliding pusher
or lever is also to form part of this moulding apparatus, and is for the
purpose of forcing out the pipe or other article when forined; but in some
cases we find it preferable to make the exterior portion of the mould suffi-
ciently large to admit of a lining of sand, against which the fluid slag is cast,
and in which the pipe or column east may be removed to the annealing oven.
This plan affords greater safety and facility for moving or packing in the oven.
In the manufacture of large blocks of slag for paving streets, we avoid
giving a square angle to them, but so construct the mould that the corners are
rounded, and less liable to break than would be the case with blocks having
sharp angles. We also form on the surface of such paving blocks grooves or
projections, for the purpose of giving a better foot-hold, and on the slides

page_text: thereof we make raised fillets or keys with corresponding grooves, whereby the
blocks when laid are so united as to prevent the sinking of one block without
the others. This mode of working keys will also be found serviceable in blocks
to be used as coping or building stones.
In the manufacture of ornamental tiles or other similar articles formed of
"slag," our Invention also consists in casting or otherwise giving to the
surface a sunken pattern, which is to be filled in with any suitable colored
glass, enamel, or other-like materials reduced to the state of coarse powder, and
afterwards fusing the coloured powder in annealing or other ovens adapted to
that purpose; or the coloured glass may be poured into the pattern in a fluid
state. We propose also, that instead of these fusible materials being employed,
the depressed patterns may be filled up with good hard coloured cements after
the tiling is laid, and in which case the pattern should be arranged so that the
joints of the tiling are covered by the cement. Or the figured surfaces may
be produced by casting or pressing the sunken patterns similar to the above;
but instead of obtaining the variety by the admixture of other substances, it
may be produced by the partial devitrification of the article, which on being
ground would give a coloured image of the pattern.
When the "slag" has by any of the above-mentioned means been formed
into the various articles required, it is necessary to be annealed or cooled
gradually and slowly, and we effect this by the following plans, which will be
found best adapted from their peculiar construction to the nature of the
different articles formed of slag, in order that the manufacture may be more
readily carried on:-
Some articles we anneal in a long oven or "lear," heated principally at
one end, and move the various articles progressively along such oven on
suitable carriages or trays. Some other articles we would place in close metal
retorts or boxes, so formed as to be moved into and out of the oven in which
they are heated; or the annealing oven may be formed by constructing the
chamber in which the articles to be annealed are placed of cast or wrought iron,
entirely surrounded by flues for heating the same, and which flues may be
afterwards used for the passage of cold air to expedite the cooling of the inner
chamber. We also anneal some articles formed of slag by burying them in
hot sand or other like material placed in close heated chambers, or when the
articles are cast in boxes containing sand, as before described, the said boxes
to be placed in the oven without removing the articles or sand.
In some cases, where we require to make very strong materials from slag,
we produce devitrification by continuing and increasing the heat of the anneal-

page_text: ing oven after the ware has been placed therein, and afterwards gradually
reducing the temperature of the oven, as in the case of simple annealing. After
the articles formed of slag have thus been formed and annealed, we propose in
some cases to improve their appearance by removing their exterior surface, by
exposing them to the action of fluoric acid, either in vapour or solution. This
process we chiefly apply to ornamental and other surfaces, which from their
nature could not be readily ground or polished.
Plates, slabs, or other large articles having plain surfaces we prefer to grind
in a machine so constructed that the plates or slabs to be ground are moved by
the action of two or more cranks in a circular path, at the same time that
every circular scratch or cut formed by the sand or other grinding material is
of an equal diameter, and both intersects and is intersected by numerous
other circles, all of which have different centres, by which action we are
enabled to produce a flat and even surface. Tiles or other small articles we
prefer to grind upon a grit stone, mounted on a vertical axis, the upper side of
which is made flat; above the stone we place a frame capable of containing in
its various compartments one or more of the said tiles. The frame is to be
placed in a slide, and by means of a slow crank motion it is to be moved
a short distance backwards and forwards, carrying the tiles or other small
articles with. This lateral motion of the tiles during the rapid rotary motion of
the stone will prevent the formation of circular furrows on the tiles, and
promote the even wearing away of the grindstone. The same arrangement
may also be used with an iron wheel in lieu of the stone, sand or emery being
used as the grinding agents. But when the articles which we manufacture of
slag are of a circular form, such as columns, vases, &c., we grind and polish
them by giving the article a rotary motion in a lathe in contact with a grinding
or polishing surface of the required configuration.
We have herein-before described by what means the grinding of large plates
or slabs of slag to a flat surface is to be effected, in which state they will be
suitable for many useful purposes; but in other cases it will be desirable to
give a fine polish to the surface of the said plates or slabs, and which we prefer
to effect by the rapid movement of a belt or strap over the surface of the plate
or slab, in a manner similar to that described in a Patent granted to Henry
Bessemer, for improvements in the manufacture of plates, sheets, or panes of
glass, bearing date the Seventeenth day of July, One thousand eight hundred
forty-seven. We have, however, found it more convenient to polish tiles or other
small articles on a revolving horizontal wheel, having a traversing frame above
.it, similar to the arrangement herein-before described in the grinding of small

page_text: tiles, but differing from it in being constructed of wood covered with felt,
which is stretched on it by a hoop, which is tightly driven on to the edge of
the table; water containing oxide. of iron is to be sprinkled on to the felt from
time to time while the table is kept in rapid rotary motion.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Henry Smith, Henry Bessemer, and Robert
Longsdon in the Great Seal Patent Office on the 21st February 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
HENRY SMITH, M.D., of Philadelphia, in the United States of America,
HENRY BESSEMER, of Baxter House, St. Pancras, and ROBERT LONGSDON,
of Hornsey Lane, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of August, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the said
William Henry Smith, Henry Bessemer, and Robert Longsdon, Her special
licence that we, the said William Henry Smith, Henry Bessemer, and Robert
Longsdon, our executors, administrators, and assigns, or such others as we,
the said William Henry Smith, Henry Bessemer, and Robert Longsdon, 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 AND
TERATMENT OF SLAG AND VITREOUS SUBSTANCES, AND THE COMBINATION OF OTHER
SUBSTANCES THEREWITH," upon the condition (amongst others) that we, the said
William Henry Smith, Henry Bessemer, and Robert Longsdon, by an
instrument in writing under our hands and seals, 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.
NOW KNOW YE, that we, the said William Henry Smith, Henry Bessemer,
and Robert Longsdon, 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:

page_text: These improvements relate chiefly to the manufacture and treatment of the
vitrified substances or "slags" produced in the process of smelting iron and
other metals. The fluid matter which flows from the smelting furnaces is con-
ducted by a gutter, which may be formed of fire clay, and covered with the same
material, instead of throwing ashes on the running slag, as at present practised.
The gutter may be also formed with an outer flue surrounding it, into which
fluc a small blast of hot air or flame is. conducted. This would prevent the
slag from cooling and becoming fixed in the gutter.
=
By the above channel the fluid "slag" is run into any one of a series of
vessels formed of fire clay, which are placed in a suitable furnace; we pre-
ferring the circular arrangement described in a Patent granted to the said
Henry Bessemer, for improvements in the manufacture of glass, and bearing
date the Twenty-second day of March, One thousand eight hundred and forty-
eight. In this arrangement the pots are heated by a fire placed central with
the series of pots or vessels. If found desirable, the heat of the slag may be
here increased; or if found sufficient, it may remain in a quiet state until the
gaseous matters have escaped, and any light impurities are floated up to the
surface, and others of a greater weight have subsided; after which the pot is
to be removed from the furnace, and its contents poured into moulds of the
required form.
A great inconvenience has hitherto been found to arise from the solidifica-
tion of a portion of the slag on the interior surface of the cars or pouring
vessels by which the slag has been brought to the moulds, in consequence of
the absorption of the heat by the said vessels; by the use of clay pots heated
to redness in the furnace before referred to, this inconvenience is prevented,
and a proper refinement of the slag is obtained. As the slag in running from
the furnace varies continually in quality and color, it is therefore desirable as
far as possible to counteract the effect of these changes, by the admixture of
either coloring matter or other materials, to render it suitable to the peculiar
purpose required.
If it is only desired to alter or modify the color of the slag, metallic oxides
alone or mixed with an alkaline salt are to be added during the filling of the
pot, and be well incorporated by stirring. But in some cases we entirely alter
the quality of the slag. This change in the composition of the slag we effect
by the admixture of dry pulverulent matters capable of combining with the
fluid slag.
Well-burnt clay reduced to powder, slacked lime, sand, or other mineral
substances may be used in such quantities as will not render the slag too solid
for working. In all cases these matters are to be heated to redness before

page_text: mixing with the melted slag, and a thorough combination of them is to be
effected by stirring. When it is desired to give the manufactured articles a
mottled appearance, we niix with the fluid slag small fragments of other slags,
or broken glass of various colors or qualities, which will become fused, or
ouly partially so, according to the time they are left in the furnace.
The combination of other materials with slag in order to modify its quality
or color having been effected in the manner described, we in some cases.
combine it with iron in the formation of table tops, mantle pieces, or other
articles; for this purpose the iron portion of the article is pickled in dilute
sulphuric acid and well cleaned; it is then made hot in a suitable oven, then
to be immersed in the fluid slag. As soon as a complete adhesion of the slag is
effected, the article is taken out and held vertically over the bath or vessel
until all superfluous portions drain off; it is then to be removed to the annealing
oven, where its temperature is to be slowly reduced. As soon as it has become
cold, the compound article inay have its surface ground and polished in the
manner herein-after described.
We have hercin-before shewn how the action of additional heat to the
materials in the pots will render it more fluid and easy to refine; but it must
be observed that this fluid condition is not suited to the working of the slag by
the processes of rolling on a table, blowing, or pressing in moulds. We there-
fore allow the furnace to cool down until the vitreous matter in the pots has
assumed that plastic condition most favorable for these operations. The slag
having been treated by any of the methods herein set forth, and being in its
purified or refined condition, is to be removed when at a suitable temperature
in its pot from the furnace, and the semi-fluid matters poured therefrom into
the moulds by tilting the pot, and immediately the pot is emptied it is to be
returned to the furnace to be recharged with slag. When ornamental tiles or
slabs of slag are required to be veined, somewhat similar in appearance to
marble, we pour the contents of two or more vessels in a united stream into
the moulds or on to the casting table, the contents of each vessel being of a
different color.
Having thus prepared the slag of suitable color and quality, we have found
that in addition to a specific quality for special purposes, that it is equally
necessary to alter the construction of the mould employed, in order to produce
the required articles at the most economical rate, and therefore the moulds to
be used for different articles of slag we construct in the following manner :-
For statuary, columns, or architectural or other florid designs, we mould the
object in moist sand or dry loam in suitable iron "flasks" or boxes; or we
make a mould composed of plaster of Paris mixed with brick dust, ashes, or

page_text: other matters capable of rendering the mould more porous and less liable to
break by heat. The mould used for casting tiles or similar small articles we
mould in sand, by forming a long, hollow trough, which we divide into suitable
spaces by inserting therein thin sheet-iron partitions.
For tessale, or other small articles requiring to be very rapidly and cheaply
moulded, on account of being made, in great numbers, we would employ
a machine described in a Patent granted to the said Henry Bessemer, for
improvements in the manufacture of glass, dated the Twenty-second day of
March, One thousand eight hundred and forty-eight, and in which machine
the moulds are formed by being sunk on the edges of a pair of, wheels, which
revolve in contact, and by their action press the slag into the forms indented
on their surfaces.
:
1
We would also claim the use of the casting table, described in a Patent
granted to the said Henry. Bessemer, dated the Thirty-first day of January,
One thousand eight hundred and forty-nine, as applied to the manufacture of
slag. The table being formed of small iron squares, fixed by, bolts to an
under plate, which is hung on a centre, so as to allow the table to assume an
inclined position, which greatly facilitates, the removal of the slab or plato
(that has been cast and rolled) into the annealing oven, the floor, of which we
place at an angle to suit the inclination of the table.
For producing flat slabs or tiles having mouldings or figured designs on. one
side of them, we use a long box or tray of metal filled with sand. The tray is
mounted on wheels, and is caused to move beneath a roller having on it the
required design in relief, which is impressed in the sand as it moves beneath
the roller. Metal frames are then laid upon the sand and open castings made
therein; or in lieu of this a plain or figured slab of granite or iron is used to
form the bed on which the moulds are laid.
For hollow articles, such as drain pipes, columns, &c., having a plain circular
or polygonal section, we construct a metal mould, truly bored or planed, and
of a slightly conical form, of which shape the core is also to partake. The
mould thus composed is fitted to a suitable frame, so arranged that the core
may be counterbalanced, and made to slide out quickly immediately that the
tube or other article is sufficiently hardened. A sliding pusher or lever is
also to form part of this moulding apparatus, and is for the purpose of forcing
out the pipe or other article when formed;- but in some cases we find it pre-
ferable to make the exterior portion of the mould sufficiently large to admit
of a lining of sand, against, which the fluid slag is cast, and in which the pipe
or column cast may be removed to the annealing oven; this plan affords
greater safety and facility for moving or packing in the oven.

page_text: In the manufacture of large blocks of slag for: paving, streets, 'we avoid
giving a square angle to them, but so construct the mould that the corners are
rounded, and less liable to break than would be the case with blocks having
sharp angles. We also form on the surface of such paving blocks grooves or
projections, for the purpose of giving a.better foot-hold, and on the sides thereof
we make raised fillets or keys with corresponding grooves, whereby the blocks
when laid are so united as to prevent the sinking of one block without the
others. This mode of working keys will also be found serviceable in blocks
to be used as coping or building stones.
"
In the manufacture of ornamental tiles or other similar. articles formed of
'slag," our Invention also consists in casting or otherwise giving to the surface
a sunken pattern, which is to be filled in with any suitable coloured glass,
enamel, or other like materials reduced to the state of course powder, and
afterwards fusing the colored powder in annealing or other ovens adapted to
that purpose; or the coloured glass may be poured into the pattern in.a fluid
state. We propose also, that instead of these fusible materials being employed,
the depressed patterns may be filled up with good hard coloured cements after
the tiling is laid, and in which case the pattern should be arranged so that the
joints of the tiling are covered by the cement. Or the figured surfaces may
be produced by casting. or pressing the sunken patterns similar to the above;
but instead of obtaining the. variety by the admixture of other substances, it
may be produced by the partial devitrification of the article, which on being
ground would give a coloured image of the pattern.
When the "slag " has by any of the above-mentioned means been formed
into the various articles required; it is necessary to be annealed or cooled
gradually and slowly; and we effect this by the following plans, which will be
found best adapted from their peculiar construction to the nature of the
different articles formed of slag, in order that the manufacture may be more
readily carried on:-Some articles we anneal in a long oven or "lear," heated
principally at one end, and move the various articles progressively along
such oven on suitable carriages or trays. Some other articles we would place
in close metal retorts or boxes, so formed as to be moved into and out of the
oven in which they are heated; or the annealing oven may be formed by
constructing the chamber in which the articles to be annealed are placed of
cast or wrought iron, entirely surrounded by flues for heating the same, and
which flues may be afterwards used for the passage of cold air, to expedite
the cooling of the inner chamber. We also anneal some articles formed of
slag by burying them in hot sand or other like material placed in close heated
chambers; or when the articles are cast in boxes containing sand, as before

page_text: described, the said boxes. to be placed in the oven without removing the
articles or sand.
:
In some cases, where we require to make very strong materials from slag,
we produce devitrification by continuing and increasing the heat of the
annealing oven, after the ware has been placed therein, and afterwards
gradually reducing the temperature of the oven, as in the case of simple
annealing. After the articles formed of slag have thus been formed and
annealed, we propose in some cases to improve their appearance by removing
their exterior surface, by exposing them to the action of fluoric acid either
in vapour or solution. This process we chiefly apply to ornamental and other
surfaces which from their nature could not be readily ground or polished.
Plates, slabs, or other large articles having plain surfaces we prefer to grind
on a machine so constructed that the plates or slabs to be ground are moved
by the action of two or more cranks in a circular path, at the same time that
every circular scratch or cut formed by the sand or other grinding material is
of an equal diameter, and both intersects and is intersected by numerous other
circles, all of which have different centres, by which action we are enabled to
produce a flat and even surface. Tiles or other small articles we prefer to
grind upon a grit stone, mounted on a vertical axis, the upper side of which
is made flat; above the stone we place a frame capable of containing in its
various compartments one or more of the said tiles. The frame is to be placed
in a slide, and by means of a slow crank motion it is to be moved a short
distance backwards and forwards, carrying the tiles or other small articles with.
This lateral motion of the tiles, during the rapid rotary motion of the stone, will
prevent the formation of circular furrows on the tiles, and promote the even
wearing away of the grindstone. The same arrangement may also be used
with an iron wheel in lieu of the stone, sand or emery being used as the
grinding agents. But when the articles which we manufacture of slag aro of
a circular form, such as columns, vases, &c., we grind and polish them by
giving the article a rotary motion in a lathe in contact with a grinding or
polishing surface of the required configuration.
We have herein-before described by what means the grinding of large
plates or slabs of slag to a flat surface is to be effected, in which state
they will be suitable for many useful purposes; but in other cases it will
be desirable to give a fine polish to the surface of the said plates or slabs,
and which we prefer to effect by the rapid movement of a belt or strap
over the surface of the plate or slab, in a manner similar to that described
in a Patent granted to Henry Bessemer, for improvements in the manu-
facture of plates, sheets, or panes of glass, bearing date the Seventeenth

page_text: day of July, One thousand eight hundred and forty-seven. We have,
however, found it more convenient to polish tiles or other small articles
on a revolving horizontal wheel, having a traversing frame above it, similar
to the arrangement herein-before described in the grinding of small tiles,
but, differing from it in being, constructed. of wood covered with felt, which
is stretched on it by a hoop, which is tightly driven on to the edge of the table.
Water containing oxide of iron is to be sprinkled on to the felt from time to
time while the table is kept in rapid rotary motion.
These improvements relate chiefly to the manufacture and treatment of the
vitrified substances or slags produced in the process of smelting iron and other
metals, and in the production of various useful and ornamental articles-there-
from, by a series of processes herein-after described, and which consist,-
Firstly, in the mode of conveying the fluid slag from the furnace through
gutters or channels into clay vessels kept heated in a suitable furnace..
Secondly, our Invention consists in casting various articles of slag in moulds
formed of sand, loam, plaster of Paris, and stone, and in moulds formed partly
of. sand and partly of iron, in an apparatus for forming, ornamental designs in
sand for the above purposes, and also in moulding or rolling small tessale or
other articles by revolving. moulds.
Thirdly, our Invention consists in an apparatus for rolling flat plates of slag
of various thicknesses.
Fourthly, our Invention consists in the construction and arrangement of
certain ovens to be used in the annealing of various articles made of slag, and
the treatment of the same by processes. suitable to the kind of article to be
annealed which act on the materials of which the slag is composed, so as in
soine, case to produce a devitrification of a part or of the whole mass of which
thei said articles are composed.
And lastly, our Invention consists in grinding and polishing various articles
made of slag, and improving the appearance of some articles by the removal of
their external surface, by the action of fluoric acid.
Firstly, with regard to our said improvements in the mode of conveying the
fluid slay from the blast furnace through gutters or channels into clay vessels,
kept heated in a suitable furnace, wherein the refinement, coloring, or
admixture of the slag with other materials is effected.-The fluid slag from the
ordinary iron blast furnace is generally allowed to flow beneath a covering of
loose ashes, a part of which is carried away with it, and adds. to its other
impurities. In the manufacture of slag we have therefore found it preferable
to conduct the fluid matter along troughs or pipes formed of fire clay-or
suitable material, and kept hot by placing them. in a flue, through which some

page_text: .
of the heated vapour of the furnace is allowed to escape, or which may be
heated by a small fire for that purpose. It has been found that the slag as it
flows from the furnace is mixed with gascous and other matters, which are
capable of separating from it slowly by subsidence, and which matters it is
necessary to separate, if a good sound material is required. The fluid slag cannot
be exposed in an open vessel for a sufficient time to effect this object without
a large portion of the mass becoming solidified. To avoid this inconvenience
we allow the crude slag to flow through the channel before described into any
one of a series of fire clay vessels, which are placed in a suitable furnace; we
preferring the circular arrangement of pots or vessels, as described in a Patent
granted to the said Henry Bessemer, for the improvements in the manufacture
of glass, and bearing date the Twenty-second day of March, One thousand
eight hundred and forty-eight, in which arrangement the pots are heated by a
fire placed in the centre of a series of them, so as to insure an equal heating
of the whole. The top of the furnace is moveable, so that by a single door
access may be had to the whole of the pots at any time.
The slag sometimes loses too much of its heat in running from the blast
furnaces, in which case its temperature may be increased in the pots; or if
found sufficient, it only requires to remain in the pots until the gaseous
matters escape from it, and other heavy impurities are separated by subsidence,
or the lighter portions have risen to the top, so that a more uniform material
is obtained for the purposes required.
When it is desired to alter the color of the slag, we put into the pots or
vessels such quantities of metallic oxides in the form of powder that will give
to the slag the desired tint; it will be found that the adding of an alkalino
salt with the metallic oxide will facilitate its admixture with the slag. In the
manufacture of some articles we produce a considerable change in the quality
of the slag, by which much of its glassy character is destroyed, and a closer
resemblance to stone is obtained. For this purpose we put into the fluid
matter sand, lime, burnt clay, or other mineral substances, first heated to
redness, care being taken that these materials are not added in such quantities
as to prevent the slag from retaining the requisite fluidity, to insure a good
cast. The substances used to alter the quality of the slag as well as the
coloring matters are to be mixed in the furnace by briskly stirring. Although
the form of furnace herein-before referred to offers many advantages in this
manufacture, nevertheless the pots may be kept hot in a furnace such as
those used for the refining of plate glass, and the same mode of removing the
pots into and out of the furnace may also be adopted. We greatly prefer the
use of clay pots (heated in a proper furnace) to iron ladles, as heretofore used,

page_text: because the slag chills rapidly in the latter, and greatly obstructs the operation
of casting, and also wastes a large portion of the raw material.
When it is desired to give the manufactured articles a mottled appearance,
we mix with the fluid slag small fragments of other slags, or broken glass of
various colors, which if heated sufficiently will become fluid, and in part blend
with the rest of the materials; but if mixed only a few minutes before the
pouring out of the slag, it will form patches of color throughout the manu-
factured article, having well defined outlines and not blended, as in the former
case. We also produce a varied or motly appearance in the slag by pouring
the contents of two or more pots in a united stream into the moulds,. the pots
having in them slag of different colors; we have found that an additional or
at least a continued heat for some time is required to properly refine the slag.
For the production of thin or ornamental castings, the slag may be used in
the fluid condition due to this bigh temperature; but if it is intended to be
rolled, blown, or pressed into moulds, it will be found necessary to allow the
furnace to become lower in temperature, until the slag assumes that degree of
plasticity requisite for these modes of working. The combination of other
materials with slag, in order to modify its quality or color, having been effected
in the manner described, we in some case combine it with iron in the forma
tion of table tops, mantle pieces, or other articles. For this purpose the iron
portion of the article is pickled in dilute sulphuric acid and well cleansed; it
is then made hot in a suitable oven, then to be immersed in the fluid slag. As
soon as a complete adhesion of the slag is effected, the article is taken out and
held vertically over the bath or vessel until all the superfluous portions drain
off; it is then to be removed to the annealing oven, and when cooled the
surface may be finished by grinding and polishing, as herein-after described.
The adhesion of the coating of slag to the iron will be increased by
perforating numerous holes in the iron plate, so as to form a key for the
slag to attach itself to; it also allows the coating on both sides of the article
to unite.
Secondly, with regard to the casting various articles of slag in moulds
formed of sand, loam, plaister of Paris, and stone, and in moulds formed
partly of sand and partly of iron, in an apparatus for forming ornamental
designs in sand, and also in moulding or rolling small tessalæ or other article
by revolving moulds-If large masses of slag are cast in iron moulds, it will
be found that the rapid abstraction of heat from their exterior surfaces, in
consequence of the high conducting power of the iron, will cause so great a
'contraction as to produce numerous cracks or fissures to be formed therein;
and if an attempt is made to remedy this defect by the rapid removal of the

page_text: mass from the mould, the fluidity of the interior portion of it will in most
cases cause the mass to fall into quite a different shape. We have, however,
discovered that these evils may be entirely prevented, by using moulds having
a very low conducting power, and which will retain the heat until by the
gradual cooling of the whole mass the central parts will become sufficiently
solidified to bear removal from the mould without any danger of their falling
out of shape; thus, for articles that can be moulded by a simple division of
the mould in two parts, we prefer to use sand of the description commonly
used in founding iron. If the casting is massive, the sand will be found to
have acquired a red heat for a thickness of an inch or more around the slag,
and thus the mould, instead of violently chilling the cast, affords it an excellent
protection. In this way columns, pedestals, vases, and numerous architectural
devices may be produced.
When plain circular work is required, or such forms as are easily moulded
in loam, we find that excellent castings may be made in a dry loam mould
previously well heated. For smaller or more delicate work, plaister of Paris
offers great facilities; but we have found it necessary to add about one-third its
weight of brick dust, or other materials capable of rendering the plaster more
porous, in order to facilitate the escape of air from its pores.
The plaster mould should be baked to dryness previous to the pouring in of
the fluid slag. Long mouldings or slabs of slag suitable for mantle pieces
and other purposes may be cast on large blocks of granite carved into the
required configuration and polished. These moulds, though better conductors
of heat than loose sand, are well suited for numerous purposes, from their
durability, and the sharpness of the.impressions obtained from them.
Plaiu square paving tiles, or small articles of a like description, may be
rapidly formed in moulds composed partly of sand and partly of iron. This
mode of moulding will be better understood by reference to Sheet A of the
Drawings annexed; where Figure 1 is a plan, Figure 2 a vertical cross
section, Figure 8 a longitudinal section, Figure 4 an end elevation, of the
moulding bar; and Figure 5 is a side elevation of the same.
t is a bar of wood, from which a number of pieces of wood u project down-
wards, of the form intended to be given to the tiles; between these pieces of
wood thin plates of .iron are inserted, the size of which is such as to allow
the iron to project about an inch on all but the upper side; the intervening
space in the iron trough is rammed in with moist sand, the moulding bar is
then withdrawn, leaving the iron plates with their edges imbedded in the sand;
a covering plate V is then laid upon the trough, which closes over all the
openings, except a small portion in the centre of each, which is left for the

page_text: inlet of the fluid slag, which is poured along the central gutter W, formed in
the cover V, which may be removed, and the trough and its contents put all
together into an annealing oven; herein-after described.
Tessale, and other articles requiring to be made very quickly, and which
from their small size would cool sufficiently rapidly,, we make by sinking the
half impressions of the object required on the edges of two moulding wheels,
as shown in Sheet A, Figures 6 and 7, where A, B, represent the moulding
wheels, which are mounted on any suitable framing, and caused to revolve in
the direction shown by the arrows. Their peripheries are notched so as to
form square surfaced tessalæ.
A lump of slag in a plastic state is shown at c, which is kept from running
over by the two side plates D, E, which form a kind of hopper, and also serve to
make the ends of the tessalæ; as the wheels revolve it will be seen that the
slag will be impressed in the teeth, receiving the final pressure at F, from
which they drop perfectly formed into a box of hot sand or ashes, and in which
they are placed in an oven to anneal.
Though we have here shown only the simplest form of moulding in this
manner, small ornaments of various descriptions and more elaborate designs
may be readily produced by having their half impressions sunk in the wheels
in a similar way. For producing flat slabs or tiles having mouldings or
figured designs on one side of them, we use the plan shown in Sheet A,
Figures 8 and 9; Figure 8 being a vertical section, and Figure 9 a plan of the
machine. G represents a long metal box or tray filled with sand. The tray
is mounted on wheels, and having on one of its upper sides a long rack H, into
which the spur wheel I gears, and causes the tray to pass under the roller J at
The roller J has the
the same speed that the periphery of the roller turns.
.
required mouldings or designs raised in relief on its outer surface, and placed at
regular distances round its circumference, according to the size of the required
article. Motion is given to the roller by the handle and pinion K, which gears
into the spur wheel I, round. the edge of the roller, which again causes the
box of sand to pass regularly under it, by which the sand is laid to a regular
level by the plain surface of the roller, and sunken impressions or moulds are
formed in the sand by the designs in relief round its surface.
Light metal frames of the desired form are then laid on the sand, to divide
and give the form and size to the slabs or tiles on which the designs are wanted.
The slag in a very fluid state is then poured into the moulds thus formed, and
the articles may, when sufficiently cooled or set, be taken out and placed in an
annealing oven; or the entire tray may be moved into the annealing lear at
once; and the goods annealed in their moulds.

page_text: Figure 10, (Sheet A, shows the apparatus we use for moulding drain pipes
or other hollow articles formed of slag. L is the outer mould, which for con-
venience for removing the article (when sufficiently cool) is divided into two
pieces which move on hinge joints at M. N is a hollow iron core, which
moves up and down in a vertical direction in the guides O, O. In order that it
may be more easily moved, a counterbalance weight P is attached to it by the
lever Q, which has springing from it at right angles the handle R, with a
small weight at the end of it, in order that when it is moved out of the
vertical position, it will by its own weight keep the core either up or down,
as required.
The mouth of the outer mould L*, into which the fluid slag is formed, is
made to project inwards, so as to nearly touch the core, leaving only suffi-
cient space for the slag to run; this will insure the end of the pipe being
cast perfect, and the surplus or head of slag will be very readily detached, on
account of its being held only by a much thinner ring than the thickness
of the pipe. In casting some articles it will not be necessary for this ring
to run completely round, but the spaces for pouring may be at intervals round
the core.
Figure 11 shows the outer part of the mould S, made large enough to admit
of a lining of sand T, which is moulded to the form required for the exterior
of the object to be cast. For pipes and other hollow articles, the iron core
and counterbalance, &c., &c., as before described and shown in Figure 10,
would be employed, but for solid ware the outer mould would only be neces-
sary. The top or mould V for pouring in is made moveable, and covers the
top surface, as before described, for finishing the upper edge of the article
When the slag is cool enough, the top is taken off, the cone with-
drawn, and the pipe is then removed in the mould, and placed in an annealing
oven. By this mode the article is protected from chilling in its passage to the
oven for annealing, and by the outer casing of iron they can be readily removed
to and stacked in the oven without fear of being bent out of shape or collapsing
while annealing.
cast.
In the manufacture of ornamental tiles or other articles of a similar descrip-
tion formed of slag, our Invention also consists in casting or otherwise giving
to the surface a sunken pattern, which is to be filled in with any suitable
colored glass, enamel, or other like materials, reduced to the state of coarse
powder.
These materials must be more fusible than the body of the tile itself, so that
when the pattern has been filled up level with the surface with this coarse
powder, the tiles are placed in an annealing oven where the heat would be

page_text: sufficient to run down the materials in the pattern without softening too
much the tile itself; or in lieu of using tho materials powdered we pour
them in a fluid state into the pattern. The tiles after having been annealed
require their surfaces finishing on any of the grinding or polishing machines
herein-after described.
Figure 12, Sheet A, shows an ornamental tile of this description; Figure 13
is a section of the same, showing the depressed pattern not filled in with any
material; but in Figure 14 the pattern is shown filled in with the fusible
materials before described.
But instead of filling up the pattern, as in Figure 14, with the fusible
materials, we would in some cases have the tiles with merely the depressed
pattern ground finished true and laid where required, and then the pattern to
be filled up with good hard colored cements. For this purpose we should
choose such patterns so arranged, that the cement would cover all the joints of
the slabs or tiles, and give the appearance of the work being in one piece on
the wall, floor, or other purpose to which it should be applied. In the manu-
facture of large blocks of slag for street paving, we avoid giving a square angle
to them, but so construct the mould that the upper corners shall be rounded
or splayed off, which would render them less liable to chip than would be the
case with sharp angles. We also find it necessary from the nature of the
slag to form the surface of the paving into grooves or projections to insure a
better foot-hold, and on the sides of the blocks we make raised fillets with
corresponding grooves for them to be fitted in.
Figure 15, Sheet A, shows the blocks with the rounded angles and the
fillets and grooves on the sides; Figure 16 shews the blocks keyed together
as before, but with their upper surface rebated out, so that when the blocks
are laid together grooves are formed thereby. For the convenience of taking
up the roadway when required, we lay a row of plain blocks without keys on
the sides at short distances apart. When blocks of slag are to be applied for
building purposes, we form similar keys on the lower and upper horizontal
surfaces, instead of using dowells and plugs, as practised with blocks of stone,
thus effecting a great saving of labor.
Thirdly, with regard to the apparatus for rolling flat plates of slag of
various thicknesses.-We have herein-before shewn by what means a variety
of articles in slag may be manufactured, but we find that neither of the
methods before referred to are suitable to the production of large thin plates
for roofing or other purposes. We therefore prefer to form such tiles or
plates by the process of rolling on a flat iron table, which we construct as
shewn on Sheet B of the Drawings annexed, where Figure 1 is a side

page_text: elevation; Figure 2,.. a longitudinal vertical section; Figure 3 is a plan;
Figures 4 and 5 are details on a larger scale. a, a, are the side frames,
held together by cross girders b, b, in which the wheels c are supported, and
on which the whole apparatus may be moyed as required. On the upper
part of the frame the casting table d is supported by trunnions e, so that it
may be tilted to such an angle as will allow the cast plate of slag to be slid
off.it with very little force. The table consists of a large flat iron plate, having
ribs dcast on the under side of it to prevent its bending. On the upper
side of it are fixed a number of small square blocks of iron d, having on their
under side a small projection at each corner, on which they rest, and which
prevents their general surface from coming in contact with the table; they are
each bolted down by, a stud or,bolt f, and are placed at a very small dis-
tance apart from each other; the whole surface is then planed true and level.
By thus using a divided surface on which, the hot fluid slag is poured; it
will be found that the expansion to which they are liable, will not warp or
split the table, in consequence of the minute space left between each block;
at the same time their heat will not be much felt by the table, because they are
in contact therewith only, at the corners, and there is room for a free circulation
of, air between them and the table d.
. At: each edge, of the table there is a groove, extending its whole length,
and into it is fitted a bar of iron g, which projects upwards above the surface
of the, blocks, a height equal to the thickness of the intended; plate of slag..
At one end of the table there is, a moveable frame h; the upper part of it is
slightly hollowed out-for the purpose of supporting the large iron roller i The
frame his attached at its upper part by joints to a rod j, which extends across
the table; its lower end is also 'attached to a pair of rocking levers k, which.
move on. a joint.l, and have a long cylindrical counterbalance weight mat
their opposite ends, by which the roller is ballanced,, When it is intended to
roll a plate on this table, the slag, in a refined state, and sufficiently cooled down
to have acquired a ductile or plastic condition is poured from the refining pot
or tilting furnace on to the table at or near d...The worknien then take hold
of the handles i of the roller (which are much longer than is shewn in the
Drawings), and roll it on to the semi-fluid matter, which becomes extended
over the surface of the table in an even stratum, the thickness of which is
regulated, as before, mentioned, by the guage bars g. As soon as the roller has
passed over the mass, the table is to be tipped up into the position shown by
dots at d', Figure 2, which will enable the workmen to push the slab or plate
of slag into the annealing, oven, without waiting for.it to be perfectly solidified,
and consequently avoiding much risk of breaking the plate, which, in the

page_text: unannealed state is very brittle. It must be observed that the floor of the
annealing oven should be constructed at the same angle as that given to
the table; the mouth of it should also be situated so far below the level of
the table as just to correspond with the table when in the inclined position.
As soon as the plate or slab is removed, the roller is moved backwards until
it reaches the frame h, which during the time of rolling assumes the position
shewn in Figure 1, but which immediately sinks into the position shewn in
Figure 2 whenever the workmen release the handles of the roller. The
sinking down of the roller affords facility for the supply of the slag from the
pots which have to pass over it, and it also prevents the 'slag from running off
that end of the table.
Fourthly, our Invention consists in the construction and arrangement of
certain ovens to be used in the annealing of various articles inade of slag, and
the treatment of the same by processes suitable to the kind of article to be
'annealed, which act on the material of which the slag is composed so as in
some cases to produce a devitrification of a part or of the whole mass of which
the said articles are composed.
.-
When the slag has been formed by any of the methods before described of
casting, pressing, moulding, or rolling into the various articles required, it is
necessary to be annealed or cooled slowly and gradually; and we effect this by
either of the following plans, which we find best adapted to the nature of the
article to be annealed, in order that the manufacture may be more readily
carried on:-
Some articles that do not want very slow cooling we anucal in. a long oven
or lear, an example of which is shewn in Sheet C, where Figure 1 is a trans-
verse section through the heating furnaces; Figure 2 is a longitudinal section;
and Figure 3, another transverse section, through the body of the oven.
The annealing lear consists of a long arched chamber a, having a heating
furnace 6 on each side, the flame and heat from which enters the chamber
by the openings c, and escapes by the chimney d, placed at some distance from
the opposite end to the fires. The carriages e, e, mounted on wheels and
running on rails, laid the entire length of the oven. The tops f, f, of these
carriages, forming the bed on which the ware is placed to be annealed, are
made of fire brick, and extend the whole width between the side walls g, g,
leaving only sufficient space to enable the carriages to pass freely along. The
fire brick is made to overhang the sides of the carriages, and by this means
the iron framework is protected from injúry by the heat. By the fires being
placed at one end, and the chimney for the escape of the flame being placed
at some distance from the opposite end, the temperature would gradually

page_text: decrease from the end next the fires, where the carriages with the ware
enter by the door h, to the opposite end, where they are pushed out at
the door k.
When a carriage is loaded with the ware it enters by the door h, and by its
being pushed in, it forces another carriage out at the opposite end by the
door ; and in order to prevent this requiring too much force, the oven may
be built to a slight incline, so that the carriages would nearly slide through
by their own weight. The ovens will have to be built to a greater or lesser
length, according to the time and gradual reduction of temperature required
for annealing the different articles.
In the manufacture of ware from slag, we find that some articles have to be
very slowly cooled, both on account of great strength required, and of the
various parts of the object being of different thicknesses; and in such cases
the regular progression of the lear would not be so suitable for annealing as
the oven shewn in Figures 4 and 5, Sheet C, when the ware would be
placed in a close metal chamber with only the door for the admission of the
goods.
Figure 4 is a transverse section, and Figure 5 is a longitudinal section, of
this form of oven. a is a long iron oven or chamber, which is heated by the
furnace 1, the heat and flame from which passes out by the small openings y
over the furnace into the fluc m under the bottom of the iron chamber, travels
its entire length, returns by tho side flues n, n, and passes over the top of the
chamber by the flue o to the chimney p.
The ware is placed in the oven, through the door g, which, when the oven
is charged, is closed and carefully luted up, so as to prevent the admission of
any cold air into the interior. The fire in the furnace is then raked out, and a
current of air is allowed to pass through the surrounding flues, which will con-
tinue to do so as long as there is any heat to abstract from the iron chamber,
and cause a draught through into the chimney. Though the inner chamber
is here shewn composed of iron, it may also be built of a thin lining of fire
brick; but we prefer iron, on account of its cooling more rapidly, and being
less likely to crack and admit currents of air on to the goods annealing.
Another modification of this plan, which we find most applicable to small
goods of similar character as those annealed in this last form of oven, is shewn
in Figure 6, where, instead of one large chamber, we make a number of sinaller
ones, and set in a similar way to gas retorts. 1, 2, represent the small iron
retorts in which the ware to be annealed is placed; s is the furnace by
which they are heated; t, t, the openings over the furnace by which the fame
and heat escapes; *, *, are the fire brick linings to protect the bottoms of the

page_text: retorts; u is the flue leading to the chimney; the heat is made to diffuse itself
regularly over the retorts by being only allowed to escape into this flue by
small openings V at equal distances apart.
For smaller goods, the last oven, shewn in Figures 4 and 5, would require to
be kept open a long time to be filled, during which time the opening and shut-
ting the door would be disadvantageous to the finer class of ware formed from
slag; we therefore divide it into a number of small chambers, closing and
luting up each one as soon as it is filled.
In some cases we construct these small retorts so that they can be taken out
of the furnace and removed to cool slowly in any other convenient place, and
their space in the furnace is refilled with other retorts, to be charged and
removed in a similar way, thus keeping up a constant succession of retorts,
and saving the necessity of raking out the fires and cooling the whole of the
surrounding brickwork. When the slag is run into large masses (such as
building blocks) in sand moulds, we effect the annealing by keeping it buried
in a large quantity of hot sand or other like material. If the articles are cast
in iron or other moulds, they may be removed and buried in the sand, placed in
close heated chambers when wished to cool more gradually; or they may
be left to the natural slow cooling that takes place in sand, without
additional heat being applied.
any other
We have found that when, as in many cases hercin-before described, the
various articles are cast in sand contained in metal trays or boxes, &c., that to
place the entire tray with the articles in their sand moulds in the annealing
oven together greatly facilitates their removal to and stacking in the oven,
and also protects them most thoroughly from chilling in the air, so that in all
cases, when it is practicable, we adopt this mode. We have also discovered
that the strength of the various articles formed of slag is greatly increased by
devitrification, and which peculiar condition is produced by continuing and in-
creasing the heat of the annealing oven after the ware has been placed therein..
The heat has to be regulated according to the nature of the slag and the
amount of devitrification required to be produced in the various articles.
For street paving, building blocks, or any articles where strength is the great
requisite, we effect the devitrification most completely, and keep up a long con-
tinued heat; but when only partial devitrification is intended, then the heat
must be applied less intensely and for a shorter period. When devitrification
takes place, a change is produced in the color and nature of the slag; it
loses its glassy appearance, and becomes more like a dense hard stone, and
frequently of a bluish grey color.

page_text: In ornamental tiles or slabs, this peculiar property we turn to account both
in producing veined ware and also regular patterns; for if tiles have designs
either depressed or raised on their surface, and are then partially devitrified, on
being ground to a level the devitrified portion will be either removed or left
with the glossy portion of the tile, and thus an image of the pattern im-
pressed will be shewn by its different color to the remaining portion of the
tile or slab.
And, lastly, with regard to our improvements in grinding and polishing
various articles made of slag, and improving the appearance of some articles
by the removal of their external surface by the action of the fluoric acid.
When large plates or slabs of slag are required to have a very flat surface,
we find it best to grind them on a machine so arranged that every part of the
plate is subjected as near as may be to the same amount of rubbing, and also
that the plates used to grind each other continually present themselves in a
different position, without which conditions a true plane cannot be obtained.
The mode by which we accomplish this object is represented on Sheet D of the
annexed Drawings, where Figure 1 is a side elevation of the apparatus; and
Figure 2, a plan of the same. A, A, are pedestals, on which the lower slab of
slag is cemented during the grinding process. These pedestals have a gutter
formed around them at A, for the purpose of receiving the sand and water
thrown off in the grinding process. B, B, are conical iron frames, one of
which is shewn in section at B*; these frames support a vertical shaft C in
the centre of them, the lower part of which shaft carries a bevilled wheel D,
which works into another bevilled wheel E, keyed on to an underground shaft
F, which may receive motion in any convenient manner from a steam engine
or other first mover, but it must be in all cases so arranged that each of the
vertical shafts C at the opposite ends of the machine more precisely at the
same speed. G is a long connecting beam, made of plate and angle iron, firmly
rivetted together, but at the same time we prefer to make it as light as possible.
At each end of it there is a brass bearing, through which the crank pins H
pass; these pins are fixed at the ends of the crank arms I, which are keyed on
to the vertical shafts C; holes are made in the connecting beam, through
which the studs J are passed. These studs are fastened to wooden frames K,
braced with iron, and while they cause the frames to follow the motion of the
beam G, they allow of their free motion on the studs J, which form an axis
for them, but do not in any way control the action of the frames K in a vertical
direction, which simply rest on the lower or bed plate with their weight, without
either support or pressure from the beam. The slabs of slag are beaded in

page_text: plaster of Paris or other cement on to the pedestals A, and another plate is in
like manner cemented to the under side of each of the frames K.. Sand or
emery and water-are sprinkled on to the uncovered parts of the lower slabs, and
the machine put in motion, which will cause the upper slabs of slag to move in
a circular path over the lower ones; but the action of which differs essentially
from a mere rotatory motion of one plate on the other, in which case an
infinite number of circles are generated; all of which are successively larger as
they are farther from the centre of motion, and by a continued action a series
of circular grooves would be formed; but it will be observed that by the action
of the machine hercin described every part of the surface of one plate describes
an equal sized circlo on the other, the diameter of which is the same as that
described by the centre of the crank pin, and thus there are a vast number of
circles intersect each other, and the tendency to form
grooves or circular
furrows is entirely avoided, and a true plane is obtained. The plates have a
slight tendency to move about their centres J, which adds to the perfection of
the process, by always changing gradually the position of the corners. of the
plates. As soon as the slabs are quite flat, the coarse sand may be washed off
and a finer kind used, until the surfaces are sufficiently smooth for the polish-
ing process, after which they are removed from the machine, and are replaced
by others.
When small articles, such as paving, tiles, &c., are required to be
ground, a sufficiently flat surface may be obtained by placing them on a hori-
zontal plate of iron, which is made to revolve quickly, and is to have sand or
emery and water sprinkled upon it from time to time. The central part of
this plate should be sunk below the general surface, or otherwise a raised
ridge will be formed round about the centre, in consequence of the inequality
of its wear. In order to keep the annular grinding surface flat, and to prevent
the formation of circular grooves or ridges upon its surface, it is necessary to
give the tiles or other articles a reciprocating motion across the revolving
plate, so that at the end of each movement a portion of the articles will over-
hang the annular grinding surface both at the inner and outer edge of it, and
thus prevent the formation of the raised ridges before referred to. The form
of apparatus by which we carry into effect this portion of our said Invention is
represented on Sheet D of the annexed Drawings, where.Figure 3 is a vertical
section, and Figure 4 is a plan of the same. a is a cavity formed in the foun-
dation, at the bottom of which there is a step 6 for the vertical shaft c to work
b
in. Near the bottom of the shaft is keyed the bevilled wheel d, by which
motion is transmitted to the machine by the first mover; at the upper part of
the cavity a there is an iron frame e, for the purpose of supporting the upper

page_text: part of the shaft c, which passes through brasses fitted therein, and has on its
upper end the large grinding wheel f, which is provided with ribs f*, which
are radial, and unite in a central boss, where they are keyed upon the shaft c.
9, 9, are walls built around the table, and support the guides h, in which the
traversing frame i moves in suitable grooves; at one end of this frame the
connecting rods are attached by joints. The opposite ends of the connecting
rods are attached to the cranks k, which receive a slow motion from the main
driving shaft in a manner well understood. The frame i represented in the
Drawings is constructed particularly with a view to grind paving tiles, one of
which may be placed in each compartment, and remain there until sufficiently
ground; it will be found to quicken the operation of grinding, if a weight or
other tiles are laid upon the tile which is being ground, if the pressure of a
single tile is not enough to produce a sufficiently rapid action.
The traversing frame should not quite touch the table, and may be
exchanged at any time for another frame with different shaped compartments,
suitable for containing other articles. The sand and water thrown off by the
centrifugal action of the machine is received in the spaces between the walls g
and m, from which it may be conveyed by a drain.
When the grinding and smoothing of the tiles or other articles are effected,
they may be removed to the polishing machine, which we construct in a pre-
cisely similar manner to the grinding machine herein lastly described, with the
exception of the surface of the revolving table, which we make of smaller
dimensions, and cover with a large sheet of felt or cloth; the tiles are laid on
this material, which is to be sprinkled with water and oxide of iron (rouge),
the process being kept up until the desired polish is obtained.
This mode of polishing is well adapted for small articles, as it affords great
facility for their removal, &c.; but for the polishing of large slabs or plates of
slag, we prefer to use the apparatus represented in Sheet E of the annexed
Drawings, where Figure 1 is a side elevation, Figure 2 is a cross section,
Figure 3 a plan, and Figure 4 details, of part of the driving gear. A is the
bed or table of the machine, formed with a flat piece of slate mounted on
brickwork, on which the smoothly ground slab or plate of slag is placed; it is
prevented from sliding off the table by the ribs of metal A*, which is let into
the table. B is the main driving shaft, supported on the brackets C, which
are bolted to the wall of the building. On the shaft B there is a drum D, and
it has also resting upon it one end of the frame E, the shaft passing through
suitable brasses at E, where the ends of the frame are formed similar to
an ordinary plummer block, sunk journals being formed in the main driving

page_text: shaft to retain it in its proper place. The opposite end of the frame E is sup-
ported on a wheel F, and has a shaft G extending across it, in the centre of
which is fixed the drum II; a strap or belt is stretched tightly over the
drums D and H by means of the tightening screws I. The belt or strap we
prefer to make of gutta percha, and cover its outer surface with felt, so that
the felt surface is in contact with the plate of slag.
In order that an even pressure may be exerted by the belt upon the slag,
we place a number of small rollers J, made of lead or iron, having a small
axis working in a slot formed in the roller bars K, which we prefer to make of
lance wood, which will be less liable to wear the axles than metal. Beneath
the drum D there is a small vessel containing rouge and water; it also con-
tains two small rollers, the one of which comes in contact with the felt, and
supplies it with the requisite quantity of polishing material. The shaft B is
not provided with sunk journals at the part where it rests in the brackets C,
in order that it may be made slowly to move endwise in either direction during
its rapid rotary movement. It will be understood that the frame E, which fits
into sunk journals on the shaft must move it, and thus partake of the back-
ward and forward motion of the shaft; it will thus be seen that when the
shaft B is put in motion, the polishing belt will be made to sweep over the
surface of the plate of slag, upon which it will be forced with a uniform pres-
sure, occasioned by the weight of the rollers, at the same time the traversing
endwise of the belt will cause the whole surface of the slab to be polished, not-
withstanding that it is much wider than the belt. The traversing motion is
also very advantageous, as it is always altering the direction of the rubbing,
and prevents streaks being formed on the material, while the regular and con-
stant supply of the polishing material insures a rapid and perfect polishing to
the slag.
The mode by which the traversing motion is given to the shaft is repre-
sented in Figure 4, where B represents a portion of the main driving shaft,
supported in brackets C; attached to the walls of the building M is a leading
screw, also supported at each end in the brackets C. N is a nut, working on
the screw, and having a projecting arm which fits in between raised collars B*,
on the shaft B; there is also an arm projecting from the nut N, which
embraces the rod P. Q is a drum, which is put in motion by steam or other
power; it is keyed on to a shaft, which also carries the mitre wheel R, which
is always in gear with two other wheels S and T, which can revolve freely on
the screw M. On the inside of these wheels there is a cone friction clutch,
and between them is the double cone U, which is free to slide endwise on the

page_text: shaft, but which cannot turn round without it, in consequence of a key-way
which passes through it. .V is a weighted lever, the lower end of which is so
arranged as to move the double cone in either direction, and to keep it pressed
into the cone of whichever wheel the weight at the top of the lever inclines from.
Whenever the nut N is moved nearly to one end of, the screw, its upper arm
comes in contact with a stud Z on the rod P, and moves it endwise, until it
overbalances the weighted lever V, which will then withdraw one end of the
double cone from tlie driving wheel, and force the cone into the other wheel,
which had previously been running loose. By this means the screw will be
propelled in an opposite direction until the nut N has travelled to the other
end of the screw, when it will again overbalance the weighted lever, and
disengage one wheel and lock the other, as before, and thus a continued.
backward and forward motion of the nut N will take place, and conse-
quently a like motion will be given to the shaft B, for the purpose herein-
before explained; at the same time rotary motion is communicated to it by
a strap, which passes over the drum W, and over a wide drum fixed on
the axis of any first mover.
All articles of a circular form, such as vases,
objects formed of slag, may be ground and
polished by giving them a rotary motion in a lathe or similar apparatus,
while a block of metal of the required form is held in contact with them,
and is supplied with sand or emery and water.
columns, and plain moulded
Having now shewn how the surface of slabs, plates, tiles, or other articles of
slag may be improved 'and rendered fit for many ornamental and useful pur-
poses, we would remark that a great variety of moulded or florid objects cast
in slag do not admit of the grinding and polishing processes herein-before
named; we therefore subject them to the action of fluoric acid in solution or.
in a state of vapour, as is well understood and practised in the production of
various patterns on the surface of glass.
First, we claim the mode herein described of conveying the fluid slag in
heated gutters.
1
Second, we claim the use of clay pots in a suitable furnace for the refining
of slag.
Third, we claim the mixture of coloring or other matters with slag for the
purposes herein-before described.
Fourth, we claim the pouring together or partial nixing of two or more
different colored slags as herein described.
Fifth, we claim the coating of iron surfaces with slag, whether such surfaces
are plain or pierced, and also the grinding and polishing of the sanie.

page_text: Sixth, we claim the casting of slag in close damp 'sand moulds, and in moulds
made of dry loam.
Seventh, we claim the combined sand and iron moulds represented on Sheet
A of the annexed Drawings.
Eighth, we claim the mode herein described of moulding small articles in
slag by revolving wheels or moulds.
Ninth, we claim the apparatus herein described for forming patterns in sand
moulds, to be used in casting slag....
Tenth, we claim the mode herein described of casting pipes in slag.
Eleventh, we claim the mode herein described of forming ornamental tiles
in slag, by casting them with an indented pattern, and filling up the sunken
parts with other materials.
Twelfth, we claim the use of plaister of Paris and compounds thereof for
making moulds used in the casting of slag.
Thirteenth, we claim the use of granite, either carved or plain, for moulds
used in casting slag.
Fourteenth, we claim the manufacture of blocks of slag for paving or
other purposes, having keys or ribs formed thereon, fitting into corresponding
grooves in other contiguous blocks, for the purpose of preserving their relative
positions.
Fifteenth, we claim the casting table, represented on Sheet B of the annexed
Drawings, for forming sheets or plates of slag.
Sixteenth, we claim annealing articles formed of slag on moveable carriages
in a lear or oven.
Seventeenth, we claim the annealing of articles made of slag in retorts or
close chambers.
Eighteenth, we claim the annealing of slag in the sand or other moulds in
which it is cast.
Nineteenth, we claim the method of polishing slag represented on Sheet E
of the annexed Drawings..
Twentieth, we claim the use of fluoric acid for removing the external surface
of articles formed of slag.
Twenty-first, we claim the apparatus represented at Figures 1 and 2, Sheet
D, for grinding plates or sheets of slag.
Twenty-second, we claim the combination of a traversing frame with a
revolving grinding table, for the purpose of grinding and polishing the surfaces
of articles formed of slag.
Twenty-third, we claim the gradual cooling of slag in pots within a suitable

page_text: furnace, so as to bring the slag into the semi-fluid or plastic condition necessary
for blowing or pressing.
Twenty-fourth, we claim the mode herein described of devitrifying the
articles made of slag.
In witness whereof, we, the said William Henry Smith, Henry
Bessemer, and Robert Longsdon, have hereunto set our hands and
seals, this Twenty-first day of February, in the year of our Lord One
thousand eight hundred and fifty-five.
Witness,
B. GOBEY,
4, Old Square,
Lincoln's Inn.
WILLIAM HENRY SMITH. (L.S.)
HENRY BESSEMER.
(L.S.)
ROBERT LONGSDON.
(L.S.)