CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF GLASS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Baxter House, Old Saint Pancras Road, in the County of
Middlesex, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-second day
of March (One thousand eight hundred and forty-eight), in the eleventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Henry Bessemer, my exors, adiñiors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said Henry Bessemer,
my exors, adñiors, and assigns, or such others as I, the said Henry Bessemer,
my exors, adiiors, or assigns, should at any time agree with, and no others,
from time to time and at all times during the. term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "CERTAIN
IMPROVEMENTS IN THE MANUFACTURE OF GLASS;" in which said Letters Patent is
contained a proviso that I, the said Henry Bessemer, shall cause a particular
description of the nature of my said Invention, and in what manner the same
is to be performed, by an instrument in writing under my hand and seal,
to be inrolled in ITer said Majesty's High Court of Chancery within six

page_text: calendar months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Henry Bessemer, hereby declare that my said Invention consists,―
Firstly, of improvements in the construction and arrangement of furnaces
to be used for the founding, melting, or refining of glass, and of a crane or
lifting apparatus by which the glass pots are moved into or out of such
furnaces.
Secondly, my Invention consists of machinery by which glass in a soft or
plastic state is shaped or moulded into a variety of articles by the action of
rotative dies or moulding wheels.
Thirdly, my Invention consists of forming ornamental plates, slabs, or pieces
of glass by combining various moulded colored pieces, moulded by rotative
dies, or by other suitable means, and afterwards forming them into one piece
be semi-fusion, and ultimately giving the plate or slab a smooth and uniform
surface by grinding and polishing, and also of a method of forming other
ornamental plates or tiles of glass by embossing or moulding intaglio designs
thereon, and afterwards filling these indentations with a more fusible glass in a
state of coarse powder, sufficient heat boing then applied to fuse the powder,
and finally the surface is perfected by grinding and in some cases by
polishing.
Fourthly, my Invention consists of preserving the flatness of sheets and
plates of glass during the annealing process by using a fluid instead of a solid
substance to support them upon.
Fifthly, my Invention consists of a method of causing plates or sheets of
glass to be retained firmly on a rigid surface or table by atmospheric
pressure.
And, lastly, my Invention consists of means of causing a more rapid and
perfect grinding of the surface of plates or sheets of glass by the use of sand
recently fractured and assorted into various degrees of fineness.
Firstly, with regard to the construction' and arrangement of furnaces to be.
used for the founding, melting, or refining of glass, and of a crane or lifting
apparatus by which the glass pots are removed into and out of such furnaces,
the improvements included under this head of my Specification are represented
in Sheets A, B, C, and D, of the Drawings hereunto annexed. For the found-
ing or refining of plate or cast glass I construct a furnace as represented in
Sheets A and B. Before entering on a description of these furnaces, I will
call attention to some of the disadvantages attending the ordinary plate glass

page_text: refining furnaces now in use, and which this part of any Invention is intended
to lesson or entirely obviate. First, as the pots are required to be removed
from the furnace for casting, six or more large openings (depending on the
number of pots used) are made in the sides of the furnace large enough to
admit the pots to pass through. These openings are closed with a sort of fire-
brick door or "tuile," which is loosened with much difficulty, and wheeled on
a sort of carriage away from the furnace before the pots are removed, and in
addition to the wear and tear of these "tniles," much loss of heat is sustained
through the imperfect joint formed between them and the furnace; they also
take off much from the uniform surface of the interior of the furnace by
forming recesses or doorways, and also a loss of space within the furnace is
caused by the piers of masonry which are built between these openings to
support the roof of the furnace; a great loss of heat is also sustained during the
shovelling on of the coals both by radiation of heat from and the influx of
cold air into the openings through which the fuel is supplied; and further,
these openings for fuel being between the two rows, of pots an additional loss
of space is sustained within the furnace. The pots are also placed with one
side to the fire and the other to the openings through which they are removed,
causing a difference in temperature of the two sides highly calculated to crack
and destroy them, particularly if cold air comes in contact with them by being
drawn in between the sides of the tuile. There are other disadvantages
attending the ordinary construction of plate glass furnaces, such as the expense
of the large cone by which they are surmounted, the difficulty of access to the
furnace, and the exposure of the workman to the intense heat of the furnace,
which is open down to the floor during the removal of the pots.
I will now proceed to show how the defects I have pointed out may bo
lessened or entirely obviated. For this purpose I will refer to Sheet A of the
Drawings hereunto annexed, where Figure 1 is an elevation of my improved
furnace, shewing the parts below ground; also, in elevation, part of the wall
of the cave or stoke hole being removed (as shewn at P*) for that purpose.
Figure 2 is a vertical section on the line A, B, of the plan. Figure 3,
Sheet B, Figure 1, Sheet B, is a horizontal section on the line C, D, of
Figure 2, Slicet A. Figure 2, Sheet B, is a plan of such part of the furnace
as is seen above the floor line of Figure 1, Sheet A. Figure 3, Sheet B,
is a horizontal section on the line F, F, of Figure 2, Sheet A. Figure 4,
Sheet B, is a horizontal section on the line G, H, of Figure 2, Sheet A;
and Figure 5, Sheet B, is a horizontal section of the line I, J, of Figure 2,
Sheet A. In each of the Sheets A and B any letter or number used to denote
a particular part in one of them is also used to denote the same part where-

page_text: ever it may again occur. (a) is a circular fire chamber of a slightly conical
forin, communicating at its upper and smaller end with a low vaulted chamber
(b), which is also circular but of much larger diameter than the part (a).
The bottom or floor of the chamber (6) is flat, and forms the "siege" or seat
on which the glass pots are placed, or they may be placed on a slightly raised
portion (c) of the floor, which is made a few inches higher than the general
level on purpose to rest the pots upon. This portion (c) is somewhat less in
width than the diameter of the pots, in order that their lower edge may
project a little beyond it, so that the pots may be more easily grasped by the
lifting apparatus to be herein-after described. The crown or dome (d) of the
furnace rises but slightly in the centre, and is built of fire-brick or masonry
fitted into a large flanged or angle iron ring (e) sufficiently strong to form an
adequate abutment to the thrust of the dome (d). The outer wall (f) of the
furnace is also cylindrical, and rises perpendicularly a little above the level of
the mouth of the pots, and is protected at the upper external edge of it by a
strong cast-iron angle ring, (9), into which twelve anti-friction wheels (h) are
fitted so as to rise about half an inch through openings made in the upper side
of it. The ring (e) and dome (d) are supported on the anti-friction wheels
(h), and is capable of being turned round in either direction. It is obvious
that for this purpose the anti-friction wheels may be attached to either of the
rings (e or 9). The pots, which I prefer to be cylindrical, are to be placed in
a circle, each of them equidistant from the centre of the chamber (a), and
nearly or quite in contact with each other, by which arrangement a space will
be left between them and the outer wall (f) in that part of the floor of the
chamber (b) which is exterior to the ring or circle of pots. I form the orifice
of the flues (i) equal in number to the pots, and so placed with reference to
them that a line proceeding horizontally from the centre of the chamber (a),
and passing through the centre of any of the pots, will also pass over the
centre of one of the openings or flues (i.) These flues, which are seen best in
Figure 1, Sheet B, descend a short distance, and then take a nearly horizontal
course, but
may be united at one or more distant points, where they are to
terminate in vertical chimney shafts provided with dampers to regulate the
draft. On referring to Figure 2, Sheet A, it will be seen that the bottom of
the fire chamber (a) slopes from the centre outwards, and that there are six
small openings (j), which are for the purpose of allowing any slag, clinker, or s
spilt glass to run out at. There are also six other openings (k) between those
last mentioned and a little above them; these openings are the orifices of blast
or tuyere pipes. Opposite the orifices (k) there are openings with a small
slide (?) to close them up; this slide moves on a joint (n), and has a knob (0)

page_text: to move it by. In the centre of the slide (l) a piece of talc is inserted through
which the state of the fire may be observed. When these slides (1) are
moved on one side, as shewn at (*), a poker may be put in to break up the
fire from time to time, if necessary. In order to render this furnace suitable
for hot or cold blast no fire-bars are used, but a solid inclined bottom (7) of
fire-brick is used instead. The incombustible portions of the fuel in the form
of slag may be run off at the openings (5) into small cast-iron vessels (9);
placed in recesses below the openings for that purpose. When the slag or
clinker is run off the hole (2) may be stopped with a plug of fire-brick or by
moist sand, after the manner well understood and practised in stopping the
tapping holes of iron-founders' furnaces. Some distance below the bed of the
furnace (r) is a hollow ring (s), on the exterior of which the branch pipes t
are bolted by flanges. These vertical pipes (1) are joined at nearly right
angles with the nozzles or tuyeres (k). There is also a large horizontal pipe
(u), with two vertical branches, one of which is shewn by dots at (V),
Figure 2, Sheet A, and at V, V, Figure 3, Sheet B; these branches commu-
nicate with the ring (s), and consequently with the tuyere pipe (k). In the
centre of the bottom (r) of the fire chamber there is inserted the end of a
conical cast-iron pipe (W), which is curved towards one side of the base T,
through which it passes in a horizontal position, and has a flange at its lower
end, to which is bolted a cylinder (✗) and hopper (Y). Into the cylinder is
fitted a piston or plunger (Z) and piston rod (Z*). A slow reciprocating motion
is to be given to the piston Z, which may be done by a crank or by attaching
the rod to any of the reciprocating parts of a steam engine or other convenient
way, and in order to sustain the conical pipe firmly in its position a bracket (1),
is cast upon it, which is firmly embedded in the solid masonry T forming the
base of the furnace; there are also two projecting parts (2 and 2) cast on the
pipe and bracket, which serve to support the ring (s), which is bolted to them.
In Figure 2, Sheet B, a circular opening (3) is shewn in the dome, through
which one of the pots (4) is visible. This opening is for the purpose of
placing the pots into the furnace, and for removing them when their contents
are required to be poured out, and that access may be had to all of the pots
through this aperture, the dome has to be moved round until the opening (3) is
over the pot intended to be removed. To facilitate this movement of the
dome a ring of cogs (5) are formed around the exterior edge of the ring (g),
and two brackets or frames (6 and 7) are bolted to the ring (e), and are further
secured by stretchers (8). The upper part of the brackets (6 and 7) terminate
in plummer blocks (9 and 10), which form bearings for the shaft (11). This
shaft has at the cnd (11) a pinion (12) working into a wheel (13) of four

page_text: times its diameter. The axle (14) of this wheel turns in a bearing (15)
formed on the lower part of the bracket (7), and the other end of the axle
(14) turns in a bushed recess formed in a boss on the ring (e). The axis (14)
also carries a pinion (16), which works into the ring of cogs (5) formed on
the ring (9). At the opposite end of the shaft (11) there is a pinion (17),
which works into an intermediate wheel (18), which turns on a stud (18*);
and this wheel gears with another wheel (19), which is four times the
diameter of the pinion (17). The axle of the wheel (19) turns at one
end in a plummer block (20), formed on the lower part of the bracket
(6), and its other end turns in a bushed recess formed in a boss on the
ring (e). The axle of the wheel (19) also carries a pinion (21) of the same
diameter as the pinion (16), and also gears into the ring of cogs (5); the
shaft (11) has upon it two cranked handles, (22) and (23). When it is
required to move the dome of the furnace, so as to gain access to any parti-
cular pot, the handles (22) and (23) have to be turned round, by which
motion the two pinions (16) and (21) will act upon the ring of cogs (5), and
owing to the combination of wheels and pinions here described, a considerable
amount of power is obtained, and the movement of the dome easily effected,
It will be obvious that were it not for the intermediate wheel (18), the pinions
(16) and (21), which work into the ring of cogs (5), would have a tendency to
move the dome in a straight line across the furnace, and not to make it
revolve; but the intermediate wheel (18) causing the direction of motion of
the pinions (16) and (21) to be changed, the dome will move steadily round
upon the anti-friction rollers (h) whenever the handles (22 and 23) are put in
motion, and to prevent loss of heat at the joint between the rings (e and g), or
the influx of cold air therethrough, I form a channel N in the ring (9), to
contain sand or other similar matter, and fasten a hoop of thin iron (D) around
the upper ring (e), so that the hoop dips into the sand, and forms a nearly
air-tight joint all around the furnace; and that easy access may be had to the
lower part of the furnace, I construct a circular vaulted room below ground;
the outer wall (P) of this chamber has a doorway leading into it at (Q), and
steps R. From the centre of the floor of this room rises the cylindrical solid
base T of the furnace, between which and the outer wall P the arched roof U
is supported; this arch is strongly built, and sustains near its centre the outer
circular wall (f) of the low vaulted chamber (6). The line V shews the
ground level or floor line of the upper room.
Having thus enumerated the various parts comprising the furnace, I will
now point out how the same are to be used in the melting, founding, or
refining of glass. A fire is first made in the chamber (a) by throwing in wood

page_text: and coals through the opening (3) in the dome, the holes (5) being left open to
supply air. When the interior of the chamber (a) has acquired a red heat,
coals are put into the hopper (y), and the piston rod Z* being connected to a
crank or to some reciprocating part of a steam engine, a slow and uniform
motion is thus to be transmitted to it. Now when the piston (Z) is drawn
entirely from under the opening at the bottom of the hopper y, the coals or
other fuel will sink down and occupy a portion of the cylinder, and as the
piston again advances, the fuel will be propelled a short distance up the bent
conical pipe (W), and on each alternate stroke of the piston a like result will
follow; the fuel will thus be propelled up the tube (W) until it reaches the
top, and flows over into the furnace. The tube W being conical, as before
described, greatly facilitates the passage of the fuel up it, at the same time,
the fuel being wedged tightly in the tube by the force exerted upon it, it will
not sink down nor follow the receding motion of the piston, but will continue
to supply the furnace as long as the motion is kept up. The advantages of
this mode of supplying fuel are, that no raw coal dust is carried into the glass
pots, as in feeding on the top of the fire with a shovel, as at present practised;
no cold air is admitted with the fuel, nor is there any radiation of heat from a
feeding door; the labour of throwing on the coals is dispensed with; and the
fuel being admitted continually in small quantities, will keep up a more
regular temperature. And lastly, the facility of regulating the quantity of
fuel supplied by altering the speed of the piston. I have before stated that
the holes () were to be left open for the admission of air at the commence-
ment of the operation of firing, but as soon as the fuel is supplied through the
tube was described, the holes (j) are to be stopped with a plug of fire-brick,
or with damp sand, and a blast of air admitted from the twyre pipes (k). The
blast, which should be small at first, and gradually encreased, may be either
hot or cold; but an economy of fuel and saving of time would be effected by
the use of hot blast, which I therefore prefer, but make no claim thereto.
The glass pots (4), which entirely surround the mouth of the chamber (a), are
put close together, and thus form a barrier between the fire chamber (a) and
the flues (i), and consequently one side of all the pots are exposed to the
direct radiation of heat from the column of flame or heated matters which ascend
from the lower fire chamber (a); this body of flame spreading over the dome
of the furnace, gives off much of its heat to the surface of the glass within the
pots, and passing down within the space between the pots and the outer wall
heats the pots on that side, and finally makes their exit by the flues i. The
advantage to be derived from this arrangement of the pots within the furnace
are, the equal temperature of all the pots, from their being all equidistant from

page_text: the centre of the fire; there being no side openings with intermediate piers, a
larger number of pots may be used; the outer wall of the furnace has an
uniform curved surface capable of reflecting much heat upon the pots; there
are no tuiles necessary, and consequently no loss of heat, &c. from tha
source, and the flame having to descend, the space will tend to equalize the
temperature of both sides of the pots. I have before stated that access to al
the pots may be had through the opening (8) of the dome; this opening
during the time of founding is to be closed by a stopper or tile of fire-brick
bound round with iron, which may be lifted by the crane or by other
convenient means whenever it is required. There are no side openings in the
chamber (6) for the removal of the pots, but by means of a crane or lifting
apparatus herein-after described, all the pots may be removed when required
through the opening (3) of the dome, by which means fewer workmen will be
required, and those will not be exposed to such a violent heat as in the cases
where the side of the furnace are opened for the removal of the pots, and in
consequence of the flues i leading off the products of combustion from the
furnace, the large cone now used may be dispensed with, and a great facility
afforded for access to the furnace. The crane or lifting apparatus by which
tho pots are removed to and from the furnace is represented as applied to
the furnace in Sheet D of the Drawings hereunto annexed. Figure 1 is
a side elevation of the apparatus. Figure 2 is an elevation of the back
of the crane taken at right angles to Figure 1. Figure 3 is a horizontal
plan. Figure 4 is a vertical section of the frame 24, and of the levers
that grasp the pot, and Figure 5 is a horizontal plan of the frame (24).
This crane being mounted on the upper ring (e) of the furnace represented in
Sheets A and B, I use the same letters of reference as are there used to
denote such parts as occur again on Sheet D, and all other letters or figures
on Sheet D denote a repetition of parts where they occur in the different
Figures. A, A, are the two side checks or principal frames, which are bolted
at top to a piece of iron B, which also forms the upper axis, and are bolted at
their lower end to a similar piece C, which forms the lower axis; the
cheeks A are further strengthened by stretchers 1, 2, 3, 4, and 5. The
frame thus put together can be moved half a revolution on its axis, the lower
one turning in a recess formed in the boss (e¹) cast on the angle ring (c), see
Figure 1, Sheet A, and the upper axis turning in a boss formed on the large
supporting bracket D. This bracket is securely bolted to a flange (6) cast
on the angle ring (e), see Figure 2, Sheet B, and that the frame D may be
more rigidly held in its position a stout iron tension bar or stretcher E passes
through the upper part of it, and is firmly secured by a shoulder and screwed

page_text: there is also a chain
nut F, and the other end of the tension bar E extends in an inclined position
to the opposite side of the ring e, to which it is firmly attached by bolts. The
piece of iron C has an elongated arm (C*) projecting from one side of it.
This arm forms a sort of lever by which the crane is turned round on its axis;
it also serves as a support for the pillar G, the upper part of which is formed
into a plummer block H, through which the main driving shaft (I) revolves.
This shaft has at one end the cranked handle (J), and the other end (after
passing through a boss on the frame A, in which it revolves, carries the
pinion (K), which works into a toothed wheel L on the shaft M, working in
bushes let into the side cheeks A on the shaft M. There is also a pinion N,
which gears with another wheel P on the shaft Q;
drum R, keyed on the centre of the shaft Q, on which the main chain S is
coiled. The shaft Q works in bushed bearings formed in the cheeks A, A; it
passes through these brushes, and carries the two outer chain drums T, on
which the small outer chains U are coiled. The main chain (S) also passes
over the guide drum V, which turns freely on the stretcher (I); the small
chains (U) also pass over the small chain drums W, which revolve freely on
studs (X) formed on the rocking levers (Y). The axis of these levers are
hollow, and has the stretcher (3) passing through it, on which it is free to
vibrate. The casting which forms the rocking levers Y has an arm Y*
projecting on the opposite side of its axis. This arm is jointed to the end of
the connecting rod Z, by which motion is transmitted to the levers Y when
required. On the arm (C*) there is bolted a piece of iron 6, which has
bushed holes passing through it; into these holes one end of the small
rocking shafts (7 and 8) are fitted, and the other ends of them pass through
bushed projections on the side of the cheeks A. The shaft (7) has a lever
handle (9) keyed to it at one end, and has a small half-crank (10) keyed
on the other. This crank is attached to the lower end of the connecting
rod Z; the rocking shaft (8) has also a lever handle (11) keyed upon it;
and, further, along the shaft there is fixed a pinion (12), working into another
pinion (13) of equal diameter keyed on the shaft (7), so that whichever of the
lever handles (9 and 11) are moved, the same motion will be communicated
to the half-crank (10). In order that the weight suspended by the crane shall
not set the train of wheels in motion and lower itself, a notched wheel (14) is
keyed upon the main shaft I, and below this there is a stud projecting from
the pillar G, on which a handle and pall 15 are fitted, so as to lock into the
teeth of the notched wheel 14 when required, and thereby prevent the unwind-
ing of the crane. During the time that the pots are being lifted out of or into
the furnace it is necessary that the jib of the crane should be steadily main-

page_text: tained in its position, and also that that position should always be the same.
To insure this the bracket 16 is bolted to the ring (e), and is provided with a
stout steel latch 17, which terminates in a pendant handle 18. There is a
projection (C) on the under side of the arm C*, which fits into a notch in the
latch 17, by which the accurate position of the apparatus is secured, and
that the crane should deposit its load on the same spot each time, a like
arrangement is made on the opposite side of the axis of the crane, where the
bracket (19) is bolted to the ring (e), having also a handle and latch 20, for
the purpose of holding the crane firmly in its position during the time the pot
is being being deposited on a support, the nature of which will vary according
to the method of casting intended to be used in connection with this furnace.
As the pots require to be lifted as nearly as possible in a vertical direction,
and with a smooth and steady motion, the guide rods (21) and (22) are made
to slide up and down through the bosses (A' and A²), which are cast upon
the side frames (A). These bosses are accurately bored and fitted to the
stout rods (21 and 21); these rods are further steadied and united by a cross
head (23), firmly keyed to the upper end of them; the lower ends pass into
sockets formed in the iron frame (24), seen best in Figure 5, into which they
are firmly keyed. (24) are lugs projecting from the frame (24), between
which they are retained by joint pins, the claws, or grips (26). These are
stoutly made of wrought iron, and are steadied laterally by the broad joint
(26); at (27) are jointed the short levers (28), which are also jointed to a
boss (29). This boss has a stout pin (30) passing up through it. The upper
end of this pin is firmly bolted to the main chain (S), and is passed through
the counterweight (31), to which it is secured by the nut (32). The
counterweight is turned and fitted so as to move freely in the cylindrical
part (24) formed in the centre of the frame (24); around the upper part
of the counterweight there is a flange to prevent it falling through the
cylinder (24). The small side chains (U) are attached to the frames (24) at
(U), and pass, as before stated, over the tightening drums W, which may be
lifted either up or down when required. In the Drawings I have represented
the drums W at their lowest position, and the chains U slack, while the main
chain S is in a state of tension. If the lever handles (9 or 10) be pulled down,
and the shafts (7 and 8) be thereby made to move half a revolution, the crank
(10) will be reserved, and the connecting rod (Z) made to descend, and with it
the arm (Y), while the arms Y and drums W will be moved upwards. This
motion, which is shown by dots in Figure 1, will not only bring the chains (U)
into a state of tension, but the movement of the drum (W) being greater
than the slack of the chain (U), the slide rods (22 and 23), with the appa-

page_text: ratus attached to them, will move upwards a small distance; and the counter-
weight (31) being still suspended by the chain S, will, by resting on the.
elevated ends of the levers 28, force them into a nearly horizontal position,
and thereby throw open the grips (26); thus it will be seen that a half revo-
lution of either of the shafts (7 and 8) will act by means of the intermediate
mechanism upon the grips (26), and either open or close them. When a pot
is to be removed from the furnace, the jib of the cranc is to be turned round
into the position shewn in the Drawing, and there held by the latch (17).
The tile or cover having been removed from the opening (3) in the dome, seen
best in Figure 2, Sheet B, the lever handle (9) is to be pulled down, which
will open the three prongs or grips (26). The handle (J) is then turned
round, when, by means of the intermediate wheels and pinions, the chains
(U and S) will be uncoiled from their respective drums, and the slide and
grips will descend into the furnace as low as required. The handle (9) is
then to be moved up again to the position shewn in the Drawing; and the
handle J is now to be turned in the reverse direction. This will cause the
main chain to coil up upon its drum R, the first effects of which will be to lift
the counterweight (31), and draw the three grips firmly up to the bottom of
the pot, which will always be held with a power proportionate to its weight,
the chain continuing to be coiled up the side rods, and other apparatus'
attached, together with the pot, will ascend with a steady and regular motion
through the opening (3). It will then be necessary to throw the pall (15)
into the notched wheel 14. The latch (17) is now to be pressed down, and
the jib of the crane with the suspended pot is made to perform a half revo-
lution. This is effected by the workman pulling by the pillar (G), and walking
round until he arrives at the latch (20), to which the arm (C*) becomes
locked. He will then detach the pall (15), and by turning the handle (J), as
in the first instance, the pot will be lowered on to a circular block of stone, or
whatever may be placed there to receive it. As soon as the pot is set down,
the handle (11) is pulled down, and the grips thereby opened. The slido
rods, &c. can again be drawn up by turning the handle (J). The contents of
the glass pot may now be disposed of, and, by reversing the order of the
crane's motion, the pot may be again returned to the furnace, and deposited in
the exact spot from which it was taken. If it is required to deposit all the
5 pots on one spot on their removal from the furnace, it will be necessary to
employ other workmen, who will, as soon as the pot is raised through the
opening (3), turn round the dome until the crane arrives at the desired place;
and also, when materials are to be supplied to the pots, the dome is to be
round, and the materials put in through the opening (3).

page_text: Having described my improvements in furnaces to be used for melting,
founding, or refining plate or cast glass, I will now explain how the sanie
general arrangement may be modified and rendered suitable for melting,
founding, or refining glass intended to be blown for this purpose. I will refer
to Sheet (C) of the Drawings hereunto annexed, where I have shewn a furnace
so arranged. And I would here remark, that some of the arrangements or
parts represented in Sheet C may, if preferred, be used in furnaces for melting,
founding, or refining cast or plate glass, in lieu of some of the parts represented
on Sheets (A and B); and also some of the arrangements or parts shewn on
Sheets (A and B) may, if preferred, be substituted or used in the glass-
blowers' furnace, in lieu of some of the arrangements or parts shewn on
Sheet (C), and which will be hereafter more fully explained.
Figure 1, Sheet C, represents the furnace, divided by a vertical line (L, M,)
in the centre, and shewing one half as an elevation of that part of the furnace
which is above the ground-floor line, and by the removal of a part of the wall
of the cave or stoke hole, also shewing the lower part of it in elevation, the
other half of this Figure being a vertical section both above and below the
floor line.
Figure 2 is a horizontal plan of that part of the furnace which is seen
above the ground-floor line with one half of the dome removed.
Figure 8 is a horizontal section of the line (A, B, of Figure 1); and
Figure 4 is an elevation of the feeding apparatus. (A) is the dome of the
furnace, built within the angle-iron ring (B). This ring has small holes (C)
for the insertion of handspikes or levers, by which it is turned round when
required. It is also strengthened and protected on the outside by a stout s
hoop of wrought iron (D). The circular outer wall (E) of the furnace has an
outer angle-iron ring (F), on which there are twelve anti-friction rollers (G),
for the purpose of supporting the upper ring and dome. To keep the dome
from getting out of place, the ring (B) has a flange projecting downwards at
(B), which overlaps the angle-iron ring (F), and is thereby prevented from
getting out of place. The joint formed by these parts may be kept air-tight
by a luting of clay or other suitable matter. In the furnace here represented,
I have shewn twelve pots (Z), and have therefore provided twelve, openings I
in the dome, which are for the purpose of giving access to the glass blower to
charge on the materials, and gather the metal from the pots while the founding 3
is taking place. The holes (H) are closed by a stopper (I), made of fire clay,
having a square knob in the centre for the convenience of lifting them with a
pair of tongs. The pots are arranged close together in a circle, and are nearer
to the outer wall (E) than those represented in the furnace, shewn on Sheets

page_text: A and B; and the openings of the flues also differ in position, being placed in
the space between the pots, as shewn best at J in Figure 2, and by dots
at J in Figure 1. The central column or base of the furnace K is built
hollow down as far as the floor line (a) of the cave or stoke hole, and has two
small archways L opposite each other, by which the cinders are removed.
Above these arches is placed a strong framing of cast iron M, divided by sixteen
broad ribs (M1), leaving as many openings in the frame. These openings,
which are for the admission of air to the under side of the fire-bars, terminate at
top in slanting partitions M 2, through which the ribs M 1 still proceed
upwards and terminate in low arches M 3. These arches are also inclined,
but in the reverse direction to the partitions M 2, forming a narrow open
space (T) entirely round the furnace, excepting at the ribs M 1, which support
the top. On the upper side of the arches (M 3) there is formed a square
passage (N) for the circulation of water. This passage extends entirely round
the frame M, and has a pipe leading to it from an elevated cistern of water,
and on the opposite side there is another pipe leading into a drain or sewer,
and communicating also with the passage (N). The use of these pipes (and
passage N) which, to avoid confusion, are omitted in the Drawing, are for
keeping cool that part of the arches (M 3) which comes near the fire, and
which might otherwise become rapidly destroyed above the frame (M), and
resting on it is the conical fire chamber (0) built of fire-brick or stone, and
which also forms a support for the arched roof of the cave or stoke holo on one
side, and the outer wall (P) forms a support for it on the other. The bottom
of the fire chamber (0) is formed with fire-bars Q, see Figure 3), which
proceed from near the centre in a radial direction, resting at the end nearest
the centre on the ring or passage (R), formed on the feeding tube S, and the
outer ends of the fire-bars rest in a groove or angle formed on the inner side
of the partition (M 2). The fire-bars are made thinner, and also have a less
space between them at that end nearest the feed tube, and at (Q') there is a
projection cast on each side of the bar to keep them a proper distance asunder,
small
and the tail part beyond this (Q 2) is made thinner so as to allow any
cinders that may escape from the narrow opening T to fall between these tails
of the bars into the ashpit in the centre of the base (K). The feeding tube S
is constructed like that represented in Sheet (A), with the exception of the
passage (R), which forms a support to one end of the fire-bars, and admits of
the circulation of water through it to keep the mouth of the pipe from being
injured by the fire. The pipes for this supply of water I have also omitted, as
such arrangements are commonly adopted to protect tuyere pipes, and are
well understood by persons engaged in the construction of furnaces. The

page_text: hopper (U) and the piston (V), to supply coals or other fuel, is to be arranged
and used as directed in the description of the furnace represented in Sheets
(A and B). The flues (J) may be made to run into each other, or any con-
venient number of them may do so, and finally terminate in one or more
chimney shafts. Besides the admission of air through the bars, a considerable
quantity will be admitted at the openings T, through which a poker may be
introduced at any time so as to stir up every part of the fuel, and keep it
sufficiently open to cause a rapid and powerful combustion. The openings (T)
also serve to withdraw the clinkers which are formed upon the fire-bars; these
can be easily broken up by using a rod with a thin blade about six inches
long projecting from it at right angles, and putting it in between the partitions
(M 1), and inserting the blade up between the bars at that part near the
feeding tube, and then drawing it forward. The radial arrangement of the
fire-bars offer a better support to small coal, where it is admitted in the centre,
than if the bars and spaces were parallel, and as the small coal becomes caked
together and falls over towards the outside by the constant heaving-up of the
central portion, it meets with a much larger supply of air through the wido
spaces between the outer ends of the bars; but owing to the fuel having
become caked before reaching this part, only the small ashes will fall through.
(Figure 4) represents the feeding tube (S), on the back of which is cast a sort
of frame or bracket (S¹) for the purpose of supporting it in the masonry of the
furnace. It is also braced by the stretchers W, which are inserted (at W*)
in a ring cast upon the tube, and pass through the lower flange of the frame
(M), where they are secured by nuts (X), see Figure (1). In order to
remove the pots from this furnace when required, and supply their places with
new ones, an opening sufficiently large must be made in the dome (A), and a
crane or lifting apparatus, such as is represented on Sheet (D), is to be
employed, but mounted on a frame upon small truck wheels instead of being.
mounted on the dome of the furnace. This crane may then be wheeled on
the floor to the spot where it is required, and an old pot may be taken out and
a new one put in its place by using the crane as herein-before directed, the
hole in the dome being brought into a proper position for that purpose. The
opening in the dome will then be stopped up by a suitable tile or fire clay
stopper fitted to the opening and luted up with clay. It will be obvious that
the method of using a blast of hot or cold air, and a solid bottom to the fire-
chamber, as represented in Sheets (A and B), may be adapted to the glass-
blowers' furnace shown in Sheet (C), instead of using the natural draft of air
through fire-bars, as therein represented. It must also be evident that the
furnace for melting, founding, or refining plate or cast glass, as represented in

page_text: Sheets (A and B), may, instead of being supplied with hot or cold blast, as
therein directed, be made with fire-bars, and depend on natural draft for
the supply of air, as represented in the blowers' furnace on Sheet (C); and
further, both of these furnaces, instead of being supplied with fuel through
the bottom of the fire-chamber, may be supplied through an opening in the
dome or through openings in the sides of the fire-chamber, which may be
closed with a fire-door after the manner usually practised in ordinary furnaces,
although I prefer the method of supplying the fuel through the bottom of the
fire-chamber, as herein-before described.
Secondly, with regard to my improvements in shaping by machinery various
articles of glass while in a soft or plasic state, and of forming ornamental
plates or pieces. of glass by combining various colored pieces so moulded or
shaped, and afterwards forming them into one piece by fusion and giving it a
smooth and uniform surface by grinding and polishing. This machine for
moulding or shaping plastic glass is applicable to a variety of purposes, such
as moulding stoppers for bottles, chandelier drops, artificial gems, beads,
buttons, rods, knobs, handles of knives, &c., and a variety of cylindrical,
polygonal, cubical, and other solid geometrical figures, to be used for tesseloo
or mosaic works, and which may be formed of glass, white or colored, trans-
parent or opaque, according to its use or the taste of manufacturer; and
that this part of my said Invention may be fully understood, I will refer
to Sheet (E) of the Drawings hereunto annexed, where Figure 1 is
a front elevation of the machine, Figure 2 a plan, Figure (3) an end.
elevation, and Figure (4) a section of a portion of it on the line (A, B,).
of Figure 1. (a, a,) are the side frames of the machine, which are connected
by stretchers (6); on the top of the frames (a) there are flour plummer
blocks (c, d, e, and f.) in which the shafts g and h revolve. i is a drum which
receives motion by a strap j from any first mover, and by means of the cog.
wheels (k) an equal motion is transmitted to the two shafts; one end of each-
of the shafts g and h) overhang the frame, and carry upon each of them a die
or moulding wheel (y and 2). These wheels fit up against a shoulder Zon
the shaft, and are kept in their places by nuts (n), which are screwed on the
ends of the shafts. There are stops or pieces of iron (m, m,) bolted upon
the side frames, having set screws p passing through them. These screws
press against one side of the plummer blocks (c and d), which are at liberty
to slide a small distance on the side frames whenever their holding-down bolts
are slackened for that purpose. The screws p are thus enabled to make the
shafts (9 and h) approach nearer to each other when required, and con-
sequently tighten the moulding wheels against each other. On the side of the,

page_text: moulding wheels next the frame there is a piece of iron (1) screwed to the
frame by bolts at (¹), and turning upwards, fits flatly against the sides of
the moulding wheels, and on the front side of the moulding wheels there is
another piece of iron (s), having two holes at the lower end of it, through
which the ends of the shafts (9 and h) pass freely, and when the nuts (m) are
screwed up, both the moulding wheels (y and 2) and the plate of iron (s)
are retained in their places. The pieces of iron (r and s) have a hollow
part (7) and (*) formed on the side next the moulding wheels. These
hollows and the curved space between the moulding wheels form a sort of
hopper, into which the glass is dropped in a plastic state. The shape of the
hopper is best seen in Figure (4), which is a section through it. Whatever
object is intended to be moulded, it will be requisite to form a sunk impression
or die of one half of it upon each of the wheels, and so to put the cog wheels
in gear, that the two half moulds, which are secured by feathers to the
shafts (g and h), are made to perfectly coincide with each other. The machine
having been so arranged, and motion having been communicated by means of
the strap (), a piece of glass is gathered on a rod or ponty as for blowing,
and held over the hopper and allowed to drop into it by discontinuing the
motion of the rod; or a pair of shears may be applied and the soft glass cut
off after the manner practised in moulding glass in presses. The rotation of
the dies or moulding wheels will immediately draw in the glass and press it
into the shapes formed upon the wheels. The machine should be placed near
to an annealing oven or gear, in which a number of small sheet-iron troughs
are placed containing sand or charcoal powder, and as the piece of soft glass
passes through the dies, one of these troughs should be taken hold of by a
pair of pincers and drawn beneath the dies, so as to receive the articles as fast
as they are produced, and immediately transfer them to the annealing kiln;
this is exemplified in Figure 9, where W. is the trough of sand, u and v the
moulding dies, and (t) the pieces of glass falling into the sand.
I have before stated that a great variety of articles may thus be formed,
and to exemplify this I will refer to Figures 5, 6, 7, 8, 9, 10, 11, and 12,
Sheet E. Figure 6 is a view of the edge of a pair of moulding dies A, A, and
Figure 5, which is a section on the line A, B, of Figure 6, shews the central hole
B and keyway, by which they are secured to shafts of the moulding machine.
These dies are for making stoppers for cruet bottles; one of these stoppers a
is shewn in perspective on a large scale at Figure 7. When pieces of glass
for tesseloe or mosaic work are to be made of some cubic figure with parallel
sides and flat ends, the half impression of the figure is cut on each wheel, and
extends entirely across it in a manner similar to the teeth of spur wheels.

page_text: This is exemplified in Figure 8, which shews the edge of the moulding wheels
(u and v), and part of the shafts (g and h), and Figure 9 is a side elevation of
the same, shewing a piece of glass at (E) in the act of passing through, and
a number of pieces (t) formed by the moulding wheels, and being deposited on
the sand in the trough (w), which is to be supposed as moving in the direction
of the arrows marked thereon. The length of the pieces (t) is determined by
the sides of the hopper fitting close to the moulding wheels, as before ex-
plained, and is therefore equal to the thickness of the moulding wheel.
Figures 11 and 12 are side and edge views of another pair of moulding
wheels of similar construction for making small pieces square in section; the
length being also determined by the thickness of the wheel. These pieces
greatly resemble what printers designate m quadrats. When rods of con-
siderable length are required to be moulded or drawn by this machine, a
groove is turned round the periphery of two wheels, presenting, when placed
together, an apperture of the section of the intended rod, as shewn in
Figure 10, which is an edge view of a pair of such moulding wheels for pro-
ducing rods of a hexagonal cross section. In making beads, a long piece of
iron wire is to be inserted between the moulding wheels from the upper side
of them, and be allowed to be drawn in as the wheels revolve; the beads
being formed upon the wire, like beads on a string; when the beads thus
formed are annealed, the wires are to be put into diluted sulphuric acid until ⚫
the iron wire is dissolved. Beads formed by moulding in this way may
afterwards be fire-polished by churning at a high temperature in ashes, as is
well understood, or may be cut and polished according to the taste of the
manufacturers.
Thirdly, with regard to my improvements in forming ornamental plates,
slabs, or pieces of glass by combining various colored pieces moulded by
rotative dies or by other suitable means, and afterwards forming them into one
piece by semifusion, and ultimately giving the plate or slab a smooth and
uniform surface by grinding and polishing; and also with regard to my method
of forming other ornamental plates on tiles of glass by embossing or moulding
intaglio designs thereon, and afterwards filling these indentations with a more
fusible glass in a state of coarse powder, and applying sufficient heat thereto,
to fuse the powder, and finally perfecting the surface by grinding, and in
some cases by polishing. In the formation of the ornamental plates
first named under this head, I. take a number of small square rods,
resembling types, or what printers designate as m quadrats, of different
colors, and for most purposes preferably made of opaque glass. The squares
are such as would be produced by the wheels, Figures 11 and 12, on

page_text: Sheet E.
These square pieces should be arranged in boxes similar to a
printer's "case," each compartment having in it a different shade or color.
The square pieces are then to be "set up" in a small box so as to produce
the desired pattern. This operation being very similar to the setting up of
types for printing, it will be better understood if the printer's technical terms
are here made use of. On Sheet E of the Drawing hereunto annexed, I
have shewn at. Figure 20 a portion of a Greek border set up in blue and
white, &c. The parts marked 2, 2, shew the face or end of the pieces, and
the parts marked 3 the sides of the top line, this Figure being in perspective.
4 is the box or "composing stick," and 5 the handle by which it is held in
the left hand, while the pieces of colored glass are picked up with the right.
When the "composing stick" is filled its contents are to be transferred to a
flat tile, upon which they are to be supported in a similar manner to a page
of types. When a design is completed, or as much of it as is intended to
form one ornamental plate or slab, it is to be treated as follows:-
Figure 18 shews an elevation, and Figure 19 a cross section through the
centre of an ornamental plate or slab prepared for the process of semifusion.
6 is a fire tile having a slightly raised border of 6* all round its upper side.
The flat central space having been well brushed over with black lead to prevent
adhesion, the "page" of ornamental glass is put upon it, and is then plastered
in its place by a mixture of fine clay and plaster of Paris, or other suitable
material. This bank of plaster, which is marked 7, rises as high as the
top of the page of glass, and is prevented from being forced off by the
raised border on the fire tile 6. The page so arranged is put into a kiln,
such as is used by glass painters and gradually heated until the small pieces
of square glass are sufficiently softened to adhere firmly together, care being
taken that enough heat is not given to completely liquify the mass. The tile
and the plate upon it are then to be gradually cooled down in a manner well
understood by glass painters, when the bank of fire clay and plaster is cut off,
and the page of colored glass, which has become one piece, is removed from
the fire tile, and is then to be ground and polished in the same way as the
operation of grinding and polishing plate glass is now effected. The other
ornamental plates or tiles also mentioned under this head of my Invention
are manufactured as follows:-A plate of glass of the desired color is taken
and an intaglio design is impressed thereon in any of the modes now practised
for embossing glass, or instead of this, the intaglio pattern may be produced
by pressing the plastic glass in moulds in the way already practised in pressing
or stamping plates and various other figured impressions on glass. Thus far
the operation is not new or of my Invention; but I will now proceed to

page_text: explain how these intaglio impressions are to be further ornamented, and in
doing which my improvements consist.
On Sheet E, Figure 16, I have shewn an example, a tile impressed with a
design, the sides of the indentations being nearly perpendicular, and the bottom
flat. 10 represents the surface of the tile, and 11 the indented portions.
Figure 15 is a cross section through the centre of it. Figure 13 shews this
tile after it is filled with two other colored glass, and Figure 14 is a section
through the centre of it in that state. Various colored opaque glasses aro
prepared in which lead and borax are used in rather larger quantities than is
generally used for flint glass, in order to render it easily fusible. These glasses.
after fusion are ladled out into water to render them very brittle, and are
afterwards pulverized in stone mortars, or under edge stones; the powder is
sifted, and a degree of coarseness equal to the average of sand is selected as
most suitable. The operator having provided himself with an assortment
of these colored glass powders, takes such as are intended for the work to
be executed, and fills the indentations formed upon the tile with these powders,
as represented in Figures 13 and 14. They are then submitted to the same
operation of semifusion as before described under this head; but the plate
or tile on which the intaglio impression it formed being made of glass without
lead or borax, and with an unusually small quantity of alkali will be much-
more difficult of fusion than the powder it contains; it will consequently.
allow the powder to be melted without losing its shape. The annealing or slow
cooling of the mass having taken place as before directed, the surface of the
plate or tile may be ground level, and in some cases polished, each of which
operations are to be performed in the same manner as already practised in
the grinding and polishing of plate glass. In some cases the pieces of glass
produced by moulding wheels, as herein-before described, may be used without
being fused together by merely imbedding in cement, as is well understood
in laying down of tesselated pavements. An example of this kind is given in.
Figure 17, Sheet E, in which the pieces t, Figure 9, are made of three shades
of blue and arranged together.
Fourthly, with regard to my improvements in preserving the flatness of
sheets or plates of glass during the annealing process by using a fluid instead
of a solid substance to support them upon. In the annealing of large sheets
of plate glass in the ordinary way great difficulty has been found in preserving
the flatness and uniformity of surface required in the bottoms of kilns or
ovens used for that purpose, more particularly so as the heat to which
the floors of these ovens are subjected at different times, and the alternate
cooling of them for the annealing of each plate, tends greatly to warp and
T 9

page_text: my
distort them, however flat they may have been originally made, and
also the inequalities of the floors of annealing ovens sometimes cause the
fracture of large sheets of glass in consequence of the glass taking an impress
of the uneven surface which they present, and as contraction of the plate takes
place in cooling, the glass having sunk into the hollow parts of the floor, the
plate is prevented from sliding over the surface of it in the act of contracting,
and therefore causes a fracture of the plate. To avoid these difficulties, and render
the plate of glass as true as possible, I make use of the flat surface naturally
presented by fluids in a state of rest, and which flat surface neither time nor
the changes of temperature can ever render untrue, nor can it impede the ten-
dency to contract which the cooling of the pláte naturally produces, and which
will be effected without any strain upon the plate, which in this case will have
the freedom of motion due to a floating body; and to bring this part of
Invention into practical operation, I use the apparatus represented in
Figures 1, 2, 3, 4, and 5, on Sheet (F) of the Drawings hereunto annexed.
Figure 1 is an end elevation of the annealing kiln or oven. Figure 2 is a lon-
gitudinal section on the line A, B, of Figure 5. Figure 3 is a part of
Figure 2 on an enlarged scale. Figure 4 is a cross section on the line C, D,
of Figure 5, and Figure 5 is a sectional plan on the line E, F, of Figure 2.
(a) is the outer wall of the annealing kiln or oven, and (b) the crown or
arched roof. (c) is a fire door in front of the kiln, behind which are the fire bars
(d) and fire bridge (e). f is a horizontal flue proceeding to the further end of
the furnace, and is separated from the side flues (9) by thin walls (h). The
flues (9) descend at (9"), and are united underground and lead to a chimney
shaft placed at any convenient part of the works. Access may be had to the
flues through the front soot doors i, and back soot door ;; in the front of the
kiln there is an arch-shape casting of iron (k) which serves as a sort of girder,
and supports the brick of the arch (6), and has a long narrow flap or door (m)
hinged to it, which extends the entire width of the end of the kiln. Within
the kiln there is a large shallow pan or bath (n) made of cast iron, and having
a flat horizontal lip at (*) which extends to the outside of the kiln. The
pan (n) is supported all along the sides and ends on the outer walls (a), and
also on the two flue partitions (h). The pan or bath (n) is filled with lead or
an alloy of lead, tin, and bismuth mixed in proportions according to the tempe-
rature to which it is intended to be reduced, without the alloy becoming'solid;
an alloy of eight parts lead, three of tin, and five of bismuth, retaining its
fluidity until reduced to about the boiling point of water, or two hundred and
twelve degrees Fahrenheit. A fire is made within the furnace part, and the
heat given off to the pan entirely over its surface by the flues f and g, the

page_text: conducting power of the pan and fluid metal serving to equalise the tempe-
rature of the bath; heat will be given off from the surface of the metal and will
heat the low brick arch (c), and also the air or gases within the kiln when the
metal is first melted in the bath, and occasionally afterwards the surface of it
is to be skinned by a flat blade of thin iron fastened crosswise at the end of a
long iron rod; this may be introduced through the flap or door (m), and moved
from back to front, skimming off any dross or impurities from the surface of
the metal; these skimmings fall off the lip (n*) into a trough (p) placed on
brackets 9 attached to the brickwork of the furnace. In the back of the kiln
there is a pipe (r) and cock (s), by which hydrogen or other suitable gas may
be admitted in small quantities so as to displace the oxygen of the atmosphere
and thereby prevent the oxidation of the fluid metal. During the time of
putting in or taking out of a plate of glass, a small supply of gas may be
turned on so, as rather to encourage an efflux of gas rather than an influx of
atmospheric air. When a sheet of glass is intended to be annealed, and the kiln
is brought up to a proper temperature, the flap (m) is lifted, and the casting
table (if one be used for making the plate) is brought as near the mouth of
the kiln as possible, see Figure 3, where t is the casting table and (u) the sheet
of plastic glass represented as partly pushed into the kiln, and its end (u*)
floated on the fluid metal, which will support it in precisely the same way as
a sheet of glass is floated on the surface of mercury in the operation of silver-
ing glass. As soon as the plate is entirely within the oven the door (m) is shut
down, and the plate allowed gradually to cool down by the radiation of heat from
the kiln. As soon as the plate has become perfectly rigid, and consequently
taken a true and level surface from the fluid, it may be floated off and piled in
a suitable oven, or otherwise disposed of in any of the methods used for piling
glass, or the glass may be cooled down as low as is generally practised in
annealing plate glass before it is withdrawn from the kiln. It will be obvious
that this method of annealing may be applied to any description of glass where
a flat surface is required without reference to the size of the sheet or plate to
be annealed.
•
Fifthly, with regard to my method of causing plates or sheets of glass to be
retained firmly upon a rigid surface or table by atmospheric pressure. In the
process of polishing sheets or plates of glass it is usual to fix them to a table
or surface by cementing them with plaster of Paris; this causes a delay of
time, as the machines used for polishing cannot be worked during the time of
fixing the plates, nor during the time of imbedding a plate and preparing to
put it down on the other side. To avoid the loss of time of working of the
machine, the labour of bedding in plaster, and the consumption of plaster of

page_text: Paris, I make use of the pressure of the atmosphere alone as the means of
holding down the plate, and that the method of so doing may be well under-
stood I will refer to Sheet F of the Drawings hereunto annexed, where
Figures 6, 7, 8, and 9 represent the table or bed on which the glass is to be
retained for polishing, Figure 6 being a plan of the iron frame with the bed
stone removed. Figure 7 is a vertical section on the line A, B, of Figure 9.
Figure 8 is a longitudinal elevation, and Figure 9 a plan. (a) is a shallow
rectangular box of cast iron, being divided into compartments by the ribs (6),
which cross each other at right angles; these ribs have hollows made in them
at *, for the purpose of communication of air from one compartment to the
other. Around the external edge of the box there is a raised fillet (a*), into
which is fitted a stout slab of slate (c), or other suitable material, which is first
planed flat on both sides, and has a great number of very small holes (e) drilled
through it; these holes are made conical, being smallest at the outer end of
them. The cast-iron box or bed is provided with pipes ƒ and g and cocks h
and i, and the whole is mounted on a brick foundation (k) or on the framing of
the polishing machine, this depending on the sort of polishing machine to be
used in connection with it. The slab of slate is to be imbedded in Turner's
cement or asphalt; for this purpose the iron box must be made hot, and the
cement put into the angle formed all round by the raised fillet (a*), and also
the cement is to be put upon all the cross ribs (b). The slab of slate being
then pressed into its seat will form an air-tight junction with the iron box, and
will be further supported by each of the ribs (6), the intervening bed of cement
compensating for any inequality of surface. When the slate. is thus. bedded
it is to be ground to a true and smooth plane by the machines used to grind
plate glass. In order to use this apparatus, an air pump or other suitable
exhausting apparatus must be provided, and placed as near as is convenient to
the room in which the polishing is to be carried on. An air vessel, made of
iron, similar to a cylindrical steam boiler, should be placed in connection with
the exhausting apparatus, and the air within it constantly kept a few pounds
per square inch below the pressure of the atmosphere. The pipe ƒ commu-
nicates between the interior of the box a, and this air vessel whenever the
cock (h) is opened. I will now explain the mode of operation :-The air being
exhausted from the air vessels before referred to, and the perforated surface of
the slate table having been wiped clean, a sheet or sheets of glass are laid
upon it. The cock h is then opened, and the air, rushing from the box (a)
into the exhausted air vessel, it will immediately take in through the per-
forations a portion of the air occupying the space between the slate table and
the plate or plates of glass, the external atmosphere pressing on the glass with

page_text: a force in proportion to the amount of exhaustion. The plate or plates will be
found to be for the time fixed upon the table, and will bear the polishing
rubbers without movement. When the plates are polished on one side, and
require to be turned over, so as to enable the other side to be polished, the
cock h is to be closed, and the cock i opened,. the pipe (9), which communicates
with the atmosphere, will instantly admit it, the equilibrium of pressure will be
restored, and the plate of glass will be as easily removed as if it had been
merely placed on a common table. When the plates have been turned over,
and laid the other side upwards upon the table, the cock i is to be shut, and
the cock h again opened, when the plate will again be firmly and flatly held in
contact with the slate table. When the plates are too small to cover all the
holes in the slate, a waste strip of glass should be laid over them, or a piece of
tin-foil or other substance that will easily prevent an unnecessary influx of
external air, which would have the effect of throwing an increased duty on the
exhausting apparatus. Any number required of the perforated surfaces may
be made to communicate with one air vessel and exhausting apparatus, pro-
vided the latter is made of sufficient power; and it will also be obvious that
plates or sheets of glass may thus be held in contact with flat rigid surfaces,
for the purpose of being ground as well as for the process of polishing.
And, lastly, with regard to my improvements for causing a more rapid and
perfect grinding of the surface of plates or sheets of glass by the use of sand,
recently fractured and assorted into various degrees of fineness. Sand, such
as is generally used for the purpose of grinding glass, is more or less water
worn, and the angles of some of the grains entirely disappear, presenting the
appearance of irregular spheroids, and but ill calculated to cut into the smooth
surface of glass. There is also a great difference in the natural size of the
grains of sand, which prevent a fine polish being given by sand used in its
natural state.
Now, the object of this last part of my improvements is to render the sand
capable of cutting rapidly into the surface of the glass, and of leaving it finally
in a more perfect state. For this purpose very coarse sand is to be preferred.
It is to be crushed under edge stones, and the splintered fragments of the
large grains are to be separated by wire sieves of different degrees of fineness;
and that portion which is too fine to be still further divided by sieves, is to be
"washed," as the process is called by emery makers. The sand, thus pre-
pared, may be used, each quality in succession, until by the use of the fine
qualities a smooth surface is obtained, free from the deep furrows produced by
sand. When used in the natural state, the recently-fractured particles of sand
will, by means of the superior sharpness of their angles, act more rapidly and

page_text: -
require less power to reduce the surface of the glass; and the minute frag-
'ments, which are separated by washing, will also produce a smoother surface
than has hitherto been produced by the use of sand. alone.
Having thus described the nature of my Invention, I desire it to be under-
stood that I do not confine myself to the details so long as the peculiar
character of either part of my Invention be retained; and I make no claim to
the mechanical parts separately. And I would remark, in respect to the first
part of my Invention, that although I prefer the various improvements for
constructing furnaces for the manufacture of glass should be combined and
used as described, yet some of the improvements may be used without others.
And I claim,
Firstly, the arrangement and combination of the various parts composing
the furnaces for melting, founding, or refining glass, as herein-before described
in respect to Drawings A, B, and C.
.I also claim separately, as applied to furnaces for melting, founding, or
refining glass, the mode herein described of supplying fuel beneath the fire.
I also claim separately, as applied to furnaces for melting, founding, or
refining glass, brick, or other solid bottoms to the fire-chambers thereof (in
lieu of fire-bars), and the use of slag-holes for running out the liquid slag or
clinker.
I also claim separately, as applied to furnaces for melting, founding, or
refining glass, so arranging the glass pots, with reference to the position of the
fire and flues or exit passages, that the heated matters from the fire shall pass
in an upward direction on one side of the pots, and, after passing over, shall
descend on the opposite side of the pots.
I also claim separately, as applied to furnaces for melting, founding, or
refining glass, a moveable dome or crown, whereby access may be had to all
the pots through one opening.
I also claim a crane or lifting apparatus, as herein described.
Secondly, I claim the moulding or shaping of various articles in glass by
revolving dies or moulding wheels.
Thirdly, I claim the mode herein described of making ornamental plates or
pieces of glass by the semi-fusion of various moulded colored pieces, arranged
so as to produce a design or pattern.
.
I also claim the mode herein described of forming ornamental plates or
tiles, by filling intaglio designs formed thereon with colored glass in a pow-
dered state, and afterwards uniting the whole by fusion.
Fourthly, I claim the annealing of glass on the surface of fluid metal.
Fifthly, I claim the holding down of plates or sheets of glass during the

page_text: grinding or polishing process on a flat and rigid surface, by withdrawing air,
and causing the holding down of the plate or sheet to be effected by the
pressure of the atmosphere on the plate or sheet, as herein-before described.
And,
Lastly, I claim the method herein-before described of causing a more rapid
and perfect grinding of the surfaces of sheets or plates of glass, by fracturing
the grains of sand used for that purpose, and afterwards separating the frag-
ments into various degrees of fineness, thereby producing sharper cutting
angles on them.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Twenty-second day of September, in the year of
our Lord One thousand eight hundred and forty-eight.