IMPROVEMENTS IN EXPRESSING AND TREATING OILS, AND IN THE MANUFACTURE OF VARNISHES, PIGMENTS AND PAINTS
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
BESSEMER, of Baxter House, Old St. Pancras Road, in the County of Mid-
dlesex, Engineer, and JOHN SHARP CROMARTIE HEYWOOD, of Islington, in the
same County, 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 Fifteenth day of May,
One thousand eight hundred and forty-nine, in the twelfth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Henry Bessemer and John Sharp Cromartie Heywood, our exors, adññors, and
assigns, Her especial licence, full power, sole privilege and authority, that we,
the said Henry Bessemer and John Sharp Cromartie Heywood, our, exors,
admors, and assigns, or such others as we, the said Henry Bessemer and John
Sharp Cromartie Heywood, our exors, admors, 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, and in the Islands of Guernsey, Jersey, Alderney, Sark, and Man,
and in all Her Majesty's Colonies and Plantations abroad, our Invention of
"IMPROVEMENTS IN EXPRESSING AND TREATING OILS, AND IN THE MANUFACTURE OF
VARNISHES, PIGMENTS, AND PAINTS;" in which said Letters Patent is contained
a proviso that we, the said Henry Bessemer and John Sharp Cromartie

page_text: Heywood, or one of us, shall cause a particular description of the nature of
our said Invention, and in what manner the same is to be performed, by an
instrument in writing under our hands and seals, or under the hand and seal
of one of us, to be enrolled in Her Majesty's High Court of Chancery within
six 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, we, the said
Henry Bessemer and John Sharp Cromartie Heywood, do hereby declare that
the nature of our said Invention consists,-
Firstly, of arranging machinery for expressing oils and oleaginous matters
from the substances in which the same are contained.
Secondly, with regard to our method of treating oils and oleaginous matters
while in combination with the vegetable or animal substances from which they
are obtained, by combining them with water, or water impregnated with
alkaline matters, by means of hydraulic pressure in close vessels.
Thirdly, our Invention consists of a method of regulating the heat applied
to vessels used in the manufacture of varnishes, by the application thereto of a
metallic bath and air bath, and also in a means of drawing off and condensing
the vapours that arise from the gums and oil in the manufacture of varnish,
and in the boiling of oils to be used in the manufacture of paints.
Fourthly, our Invention consists in giving a greater body or opacity to such
colors or pigments as are produced by the combination of silica with alkali,
alkaline earths, or metallic oxides, and forming thereby vitreous colors. And,
Lastly, our Invention consists in an apparatus or. mill for grinding pigments
or paints.
Firstly, with regard to our arrangement of machinery for expressing oils
and oleaginous matters from the substances in which. the same may be con-
.tained. To accomplish this purpose we use the "oil press," shewn in Sheet A
of the Drawings hereunto annexed, where Figure 1 is a side clevation;
Figure 2, a plan; Figure 3, a longitudinal section on the line. A, B, of
Figure 2; and Figure 4 is a section of part of the pressing cylinder on va
larger scale. The bed plate or framing a we prefer to be cast in one piece,
and forms at a a cistern for the reception of the oily matters which, fall
therein as they are expressed.. At the opposite end of the bed plate there are
formed projections a³, in which brasses bare fitted, and, with the caps c, form
bearings for the crank shaft d to turn in. There are also two other pro-
jections a³, a³, cast on to the bed plate, and are provided with caps e in a
similar manner to the caps of plummer blocks. These caps are for the pur-

page_text: pose of retaining firmly in its place the pressing cylinder f, which we prefer to
make of tough gun metal, and of such thickness as to be capable of with-
standing a considerable amount of internal pressure. Within the cylinder f. is
fitted what we term the lining, seen best at Figure 4. This lining consists of
a gun-metal tube n, having a spiral groover cut on the outside of it, and
consequently presenting the appearance of an ordinary square-threaded screw.
At very short intervals all along the spiral groove there are conical holes s
drilled through the tube n, and communicating with the interior of it. At n¹
the inside of the tube is enlarged, and is provided with a steel collar t. The
opposite end of the tube at n¹ is reduced in diameter, and is provided externally
with a steel collar u. A plain cylindrical bag V, with open ends, formed of
fustian, hair cloth, or other like pervious material, is made of such a diameter
as will fit closely to the inside of the tube n; and within this bag is placed a
cylinder W of wire gauze or finely-perforated metal. The steel collar tis
forced into the end of the wire gauze, by which it becomes driven into the
recess formed at n¹, and is securely held there by the pressure of the collar t.
The bag V and wire gauze W is then tightly stretched over the end n³ of the
tube, and the collar a driven tightly on, by which means the bag and wire
gauze are securely held in their places. The lining tube n is then put into
the pressing cylinder as far as the shoulder g. A tubular piece h is next put
in and brought into contact with the collar u, and then the gland i is screwed
home, whereby the lining n is firmly retained within the pressing cylinder.
The end of the pressing cylinder is contracted at f¹, and forms a shoulder for
the abutment of the collar j, the diameter of the aperture in which regulates
the pressure to which the matters under operation are subjected. Within the
tube n there is fitted a solid plunger k, which receives motion from the-
crank & by means of the connecting rod 1, the parallel motion being obtained
by the wheels m, on the cross head O, traversing on the side of the bed
plate at a'. a is a hopper, bolted to a flange f on the pressing cylinder,
and communicating therewith. There is also an opening in the tube.n
at n', corresponding with the opening into the hopper, so that any mate.
rials placed in the hopper may fall into the tube n, when the plunger k
is withdrawn from beneath the opening. At that part of the pressing cylin-
der which is occupied by the "lining" there are drilled numerous small
holes f³, which communicate at various points with the spiral groove in the
tube n.
On the outside of the pressing cylinder there are formed two collars
f 4,f4, which abut against the projecting pieces a³ and caps e, and cause the
pressing cylinder to be retained firmly in its place. When steam power is to
be employed to give motion to the oil press, I prefer to have the crank which is

page_text: actuated by the steam piston formed on the end d, on the crank shaft of the
oil press, and placed at such an angle to the crank d, that when the crank d
is pushing the plunger k to the end of its stroke, the steam piston will be at
half stroke, whereby the motive power applied will be greatest at the time
that the press offers the greatest resistance, and the steam piston also, when
passing its dead points, will have to overcome the friction of the machinery
only, as the plunger k will be in the middle of its back stroke. When any
other motive power is applied to turn the crank d, it will be necessary to put
a fly wheel on the shaft d', as also such cog wheels as will be necessary to
connect it with the first mover. When this apparatus is to be employed in
expressing linseed oil, the seed, after having been ground and treated in the
way now commonly practised, is put into the hopper, and motion being
transmitted to the crank in the manner before described, the plunger k .will
commence a reciprocating movement in the tube n of the pressing cylinder.
Each time that it recedes in the direction of the crank it will move from under
the opening in the hopper, and allow a portion of the seed to fall into the
tube, while the reverse motion of the plunger will drive it towards the open
end of the cylinder, its passage being much retarded by the friction against
the sides of the tube lining, but chiefly by the contraction of the escape
aperture through the collar j, which will produce a considerable amount of
resistance, and consequently the plunger will have to exert an amount
of pressure upon the seed in proportion as the escape aperture is made larger
or smaller. It will be observed that the collar j is made moveable, and by
withdrawing the plunger entirely from the tube, it can be exchanged at any
time for another having a larger or smaller opening. The lining may at any
time be removed from the cylinder, and the worn parts removed when it may
be found requisite so to do. The action of the plunger is somewhat like that
of the plunger of an hydraulic press pump, the seeds being pumped in at one
end of the pressing cylinder, and allowed to escape at the other, while the
whole of the interior of the pressing cylinder that contains seed is lined with
hair cloth or other suitable pervious material, and that it may be protected
from injury, this material is covered with wire gauze, or finely perforated
metal. The bag is thus completely defended from within, while it is supported
at every part by the tube'n on the outside, and is thus subjected to very little
wear, and to no risk of bursting. The expressed oil, passing through the wire
gauze and bag, finds its way through the perforations S into the spiral channel
r, and from thence it finds ready egress by the perforations f³ in the pressing
cylinder, and as it falls is received by the cistern a', from which it can be
drawn by the pipe y. Although we have here shewn one pressing cylinder

page_text: only, it is obvious that two or more may be used side by side, actuated either
by one crank throw or by separate throws upon one shaft, placed with reference
to each other in such manner as greatly to equalize the amount of resistance
throughout the revolution of the crank shaft; and although we have herein
shewn a cylindrical pressing plunger, yet it will be obvious that instead
thereof an angular section may be given to the pressing vessel and plunger;
and further, it will be seen that although we have herein described the oil
press operating upon linseed, the same may be applied to express oils from
other seeds and matters containing oils. In the Drawings of the oil press
hereunto annexed, we have not shewn any method for heating the linseed
meal, or other matters to be subjected to pressure therein, but as it is known
to be desirable to heat some matters from which oil is to be expressed, we
will describe a method of so doing. When heat is to be applied during the
process of pressing, we prefer to make the pressing cylinder of somewhat
larger diameter, and of greater length, and to divide the cistern a¹ into two
separate compartments, over both of which the pressing cylinder is to extend ;
a strong wrought-iron tube is to enter the open end of the pressing cylinder,
and to extend about half way to the hopper, where it terininates in a solid
pointed end; this tube is to occupy the centre of the pressing cylinder, and
will consequently leave an annular space around it, which will be occupied by
the seed, meal, or other matters under operation. Steam is let into this iron
tube, and its temperature thereby raised to any desired point. The end of the
tube which extends beyond the pressing cylinder is to be securely attached to
a bracket projecting from the bed plate, so that it may be firmly held in its
position, notwithstanding the force exerted against the pointed end of it. The
effect of this arrangement will be, that, as the seed, meal, or other matters fall
into the pressing cylinder, and are pushed forward by the plunger, they will
give out a portion of their oil in that state known as "cold drawn," which will
fall into the first compartment of the cistern a'. The further progress of the
meal along the pressing cylinder will bring it in contact with the pointed end
of the heating tube; here it will have to divide itself, and pass along the
annular space between the heating tube and the lining, and being thus spread
into a thin cylindrical layer around the tube, it will readily absorb heat there-
from, when a second portion of oil will be given off and received by the
second compartment of the cistern; and thus will the operations of cold and
hot pressing be-carried on simultaneously.
Secondly, our Invention consists in a method of treating oils and oleaginous
matters while in combination with the vegetable and animal substances from
which they are obtained, by combining them with water or water impregnated

page_text: with alkaline matters by means of hydraulic pressure in close vessels. The
apparatus by which we carry out this part of our Invention is represented
on Sheet A of the Drawings hereunto annexed, where Figure 5 is an elevation,
and Figure a vertical section taken through the centre of the apparatus.
A is a cast-iron cistern, having semicircular ends, and open on the upper side.
At one end of it is fixed a cylindrical vessel B, with hemispherical ends. This
vessel is of considerable strength, and should be capable of withstanding a
pressure of five thousand pounds to the square inch. It is held in an upright
position by a flange C formed upon it, and extending around one-half of its
circumference. This flange rests upon a similar one formed around the upper
side of the cistern A, and is bolted thereto. At the upper part of the vessel B
is formed a sort of basin B', the edge of which supports an arch-shaped piece
of iron D. At the centre of the basin there is an opening into the vessel, and
an hydraulic cup leather E is secured within the opening by means of the
collar G. In the bottom of the vessel B there is also an opening, into which
is fitted a cup leather II, secured in its place by the ring J, which is firmly
bolted to the vessel B. A strong wrought-iron rod K extends from the top
of the arch D, down through the vessel B, having two enlargements or bosses
K', K², formed upon it, which are fitted to the cup leathers. The upper part
of the rod K has a screw formed upon it at K³, which passes through the
boss D and enters the boss N, in which a screw thread is formed. The
boss N is provided with handles P, by turning which the rod K. may be raised
or lowered when required. R is a pipe, through which water may be injected
.into the vessel B by a force pump, such as is generally employed to work
bydraulic presses.
S is a cock, whereby a portion of the contents of the
vessel B may be run off, and the pressure relieved when requisite. The two
bosses K and K being of equal area, whatever pressure may be excrted
within the vessel B it does not tend to raise or lower the rod K, but such
pressure, acting on the cup leathers, will keep the joint tight, and prevent the
matters under pressure from leaking out. After a certain quantity of oil or
oleaginous matters have been expressed from vegetable or animal substances,
.the remaining portions which they contain are more difficult to obtain, and
we. therefore treat the oil in combination with the substances in which it is
contained in the following manner:-The aforesaid substances, after coming
from the oil press or mill, are mixed with as much warm water, or water
slightly impregnated with alkaline matter, as will reduce them to a semi-fluid
state. They are then to be operated upon in the apparatus herein last
.described. For this purpose the handles P, P, are turned round, and the
.boss K³ withdrawn from its opening, while the boss K, which is much longer,

page_text: still close the lower aperture. The semi-fluid materials are then put into the
basin B, and full from thence into the vessel B; when it is fully charged
the rod K is again lowered into the position shewn in Figure 6.
The com-.
munication with the hydraulic press pump is then made by means of a cock
attached to the pump, from which the water flows through the pipe R in the
vessel B, and thus with a few strokes of the pump the whole of the contents
of the vessel B will be subjected to the requisite pressure. An interval of a
.
few minutes is then to be allowed for the combination of the oil and water,
and the cock S is then to be opened, and a small portion of the fluid contents of
the vessel allowed to escape into the cistern. The pressure being thus re-
lieved, the handles P, P, are to be again turned so as to lift the rod K sufficiently
high to withdraw the boss K³ from the lower opening; the contents of the
vessel B will then flow out into the cistern A, and the boss K2, being again
lowered so as to close the lower aperture, the refilling of the vessel may take
place for another operation. The pressure thus brought upon the mixture of
oleaginous matters and water will cause the oil therein contained to mix
with the water, and form a milky-looking fluid, from which the oil may be
afterwards separated from the water, either by repose in large vessels or by
evaporating the water therefrom by heat. When oil is to be used for soap
making and some other purposes, this combination of oil and water may be
used without such separation. When seed oil is thus obtained the muci-
lagenous matters assist in combining these fluids. After the materials have
been drawn off from the cistern A, and passed through a strainer, the solid
portions are to undergo another pressing, in order to displace the remaining
portion of their fluid contents. In some cases it will be found advantageous
to boil up the milky-looking fluid resulting from the operation herein last
described. in order to coagulate the albuminous portions and otherwise assist
in the purification of the oil.
Thirdly, with regard to our method of regulating the heat applied to
vessels used in the manufacture of varnishes by the application thereto of a
metallic bath and air bath, and also in the means of drawing off and con-
densing the vapours that arise from the gums and oil in the manufacture of
varnish, and in the boiling of oils to be used in the manufacture of paints.
In the manufacture of varnish, as at present carried on, the "gums" are "run"
in the gum pot by the direct application of the fire to the exterior of the thin
copper vessel, whereby the temperature is apt to rise suddenly so high as to
greatly injure and sometimes to fire the "gums," whilst at other times the
falling off of the heat below a certain point produces evils of another kind. At
the high temperature requisite for the fusion of copal, amber, animé, and

page_text: other "gums," they give off dense fumes, consisting of the more volatile con-
stituents of those bodies; the overpowering effects of these vapours are severely
felt by the workmen engaged in this department of the manufacture, occasionally
producing explosions of a serious character, while the vapours thus allowed to
escape are frequently of considerable value, either to add to the varnish or for
separate use. The gum pot requires to have its mouth left open during the
process of running the gums, so that the workmen may watch the operation
and stir up .the gum during that time. It is this which has hitherto rendered
it so difficult to prevent the escape and loss of the volatile matters before
referred to; but in order that our method of avoiding these defects of the
present process may be fully understood, we have shewn on Sheet B of the
Drawings hereunto annexed so much of our apparatus as is necessary to
render the same readily understood.
Figure 3, Sheet B, is a vertical section through the metal bath and gum
pot, and Figure 4, an horizontal section of the gum pot on the line A, B, of
Figure 3. a is the fireplace situated below the floor of the "running house,"
as usual, 6 the fire door, and c the ash-pit. Above the fire is placed a cast-
iron vessel a, bath d, which is nearly filled with an alloy of lead and tin mixed
in equal proportions, because the fusing point of pure lead is too high for the
purpose. The flue of the furnace rises at e into the flue f, which after circu-
lating round the bath leads to a chimney not shewn in the Drawings. g is
the gum pot made of thin sheet copper, and having a flange rivetted upon it.
There are to be three notches cut into this flange at equal distances around it, and
there are also three grips i fastened to the top of the bath, and corresponding
in distance with the notches in the flange h, so that when the gum pot is
pushed down into the fluid metal, the grips pass through the notches, and
by turning round the pot a small distance the flange h will be locked under
the grips and its tendency to float in the bath be counteracted. Near the
top of the gum pot there is an incision made half way around it, and the
lower part bent outwards about half an inch, leaving a space between the
two cut surfaces. On the outside of the pot there is a semicircular piece m;
rivetted to the vessel, and enclosing the part where the incision is made,
the piece m serving to strengthen the pot, and also to form a communica-
tion with the interior of it. This piece m has a short piece of pipe n projecting
from the centre of it, which comes directly over a fixed pipe p, standing
upwards from the top of the bath, and consequently by means of the pipe n
having a communication with the interior of the gum pot. The pipe p is shewn
broken off at p, No. 1, from which point it proceeds to any convenient part of
the building where it enters a common condensing "still worm," which is to

page_text: be fixed in a tub of cold water, as usual. The worm pipe after passing out at
the lower part of the tub has two branches, one descending about a foot per-
pendicularly and terminating in a cock, from which any condensed matters
from the worm may run off into a receiving vessel. The other branch of the
pipe proceeds upwards a few feet, where it is made to communicate with the
open axis of a common eccentric blowing pan or other exhausting apparatus,
the office of which is to exhaust the air from the pipe and thereby to induce a
strong current through the worm pipe, and to carry off any atmospheric air
and incondensable products that may pass through the worm. The action of
the apparatus is as follows:-The fire having been lighted and the metal in
the bath having fused, a thermometer is applied through the opening r,
and its temperature ascertained, and as soon as the requisite temperature is
arrived at, the gum pot g is put in and secured under the grips, care being
taken that it is turned round so as to allow the pipes n and p' to be exactly
opposite to each other. It is not necessary that their junction at s should be
perfectly air-tight. A charge, say twenty-eight pounds of amber, is then put
into the pot, and may be watched and stirred, as usual, through the open
mouth of the gum pot. The fan blower or other exhauster must now be put
in motion, and as tho "oil of amber," or other volatile products, arise from the
materials under operation, they will flow through the incission at 7, as shewn by
arrows. The strong current setting in by this opening (which extends around
half the diameter of the gum pot) will also cause a portion of atmospheric air
to enter by the open mouth of the pot, and mixing with the vapours will pass
with them through the condensing worm, where the condensable portions will
be liquified, and the air pass off through the fan or exhauster. Meanwhile
there would have been little difficulty in maintaining a sufficiently equal tem-
perature of the metal bath, because in the short period required to run one
charge of "gum," the temperature of so large a mass of metal could not have
undergone much change, even if the fire had been entirely withdrawn, or on
the contrary, bad been much increased; but besides this, the heat may be at
any time checked by inserting at the opening r a large picce of cold iron for
a minute or two, whereby the heat would be reduced; but it will be generally
found sufficient to rely wholly on the store of heat contained in the mass of
metal which cannot be either cooled or heated to an injurious extent during
the operation, unless the state of the fire is wholly neglected. When the gum
is run and mixed with oil, it is then to be lifted out of the metallic bath, and
its contents transferred to the boiling pot, care being taken that the side g¹ is
used for that purpose, otherwise the "gum" would enter the space 7, and cause
inconvenience. Thus during the operation of running the "gum" the heat will

page_text: have been regulated, the inconvenience and danger of the escaping fumes
prevented, while the volatile matters condensed are at the disposal of the
varnish maker, to be applied to any useful purpose.
In Figure 5, Sheet B, we have shown a section of the boiling pot, in which
the gums and oil are boiled in the making of varnishes, and which vessel may
also be employed in boiling oils to be used in making paints. A is a copper
boiling pot of the usual form, and B is a shallow cast-iron pan made very
thick, both to prevent its destruction by the fire and to cause to retain its heat
and not allow the rapid fluctuation in the temperature of the fire to act upon
the air which it contains. The pan B is supported over the fireplace C by the
flange B¹ resting on the side walls D of the furnace, the details of which may
be varied to suit the convenience of the manufacturer. The boiling pot is
suspended in the air bath or pan B by a flange A 1, rivetted around the
boiling pot, on the mouth of which is placed the cover E, which embraces the
external edge of it at E 1, and has a large central opening formed by bending
and beating out the metal to the form shewn. The curved edge of the cover at
E nearly approaches the sides of the boiling pot, and at G leaves an annular
space all around the interior of it. A pipe H leads from this space to a condensing
worm and fan or other exhauster, as herein-before described; the operation of
the apparatus will be as follows:-The fire being lighted in the furnace C, the
heat thereof will be absorbed by the bath or pan B, and the air which it con-
tains also becoming heated will in its turn impart heat to the boiling pot, the
temperature of which will not be materially influenced by the continued rise
and fall of the fire in the way it would have been if the bottom of the boiling
pot were exposed as usual to its direct influence, the blowing fan causing an
exhaustion in the pipe H, and annular space Ġ. The vapours that ascend
from the boiling oil or varnish will enter the space G by the narrow opening
at E³ (which extends entirely round the pot), and passing off to the worm will
become condensed, while the large opening in the cover allows a full exami-
nation of the process and free use of the stirrer I, by which the contents of
the boiling pot are incorporated. As the form of air bath shewn in Figure 5
requires the lifting up of the pot before it can be removed, it may be found
more convenient in some cases to form the bath or pan as represented in
.section at Figure 6, where J represents a thick cast-iron plate or pan having a
raised edge around the upper side of it, and six arms or ribs K also raised as
high as the outer edge. This plate or pan is placed on the fireplace L, and the
upper side of it level with the top of the brickwork M of the furnace. N
.represents a portion of a boiling pot placed thereon. The plate J is repre-
sented in plan at Figure 7, Sheet B, where K represents the ribs which are

page_text: for the purpose of supporting the pot while it is being removed, and Q are the
sunk spaces between them which will be occupied by air. In this form of the
apparatus the boiling pot may be moved sidewise partly off the hot plate, and
entirely removed when required without lifting it up; it will be obvious that
the metal bath may also be applied to the boiling pot, or that the air bath may
be used to run the "gums," but we prefer the arrangement before described.
Fourthly, with regard to our methods of giving a greater "body" or opacity
to such colors or pigments as are produced by the combination of silica with
alkali, alkaline carths, and metallic oxides, and forming thereby vitreous colors.
For many purposes in the arts, such as china and glass painting, there are used
colors compounded of the materials herein lastly named, and for such purposes
it is not essential such colors should be opaque; on the contrary, when applied
to the painting of glass, it is generally desirable to preserve as great an amount
of transparency as possible; but as colors formed by the combination of
metallic oxides with silica and alkaline earths and alkali are not easily acted
upon by the atmosphere, or by moisture, it is desirable to use such vitreous
colours for purposes of painting generally, but for this purpose it is necessary
that they should have sufficient "body" or opacity to cover thoroughly the
substances on which they are used. It is well known that glass of various
kinds (but more particularly that containing a large proportion of lime) under-
goes, by a long exposure to a low red heat, an entire change in the arrange-
ment of the molecules forming its substance, and passed from the ordinary
state of transparent glass to a semi-opaque body; glass in this state is
known as Reaumur porcelain. When carbonate of lime is used with silica and
soda to form glass, the result is a transparent substance, but if phosphate of
lime be used instead of carbonate, then a white opaque spongy material is
produced. The oxide of tin, when used in combination with it, also adds to
the amount of opacity. Taking advantage of these facts we proceed as follows:
-Into an ordinary glasshouse pot we put the following mixture:-Five
bundred pounds of white sand, two hundred pounds of dry sulphate of soda,
one hundred and seventy pounds of phosphate of lime, and eight pounds of
charcoal, the latter material being added to decompose and dissipate the acid
of the sulphate of soda. The whole mixture, when melted in a glasshouse or
other suitable furnace, is to be ladled out of the pot into cold water; this
sudden chilling will break the opaque glassy mass into small fragments, which
are afterwards collected and put into retorts of clay similar to those generally
employed for making gas from coal, and a temperature from 700° to 900°
Fahrenheit is to be maintained for a period of three or four days, when the
ends of the retort being opened the material is to be raked out in its heated

page_text: state, and again allowed to fall into cold water. The portions of matter thus
treated will be again further disintegrated and rendered so brittle as to be
casily reduced to powder under the ordinary edge stone mill. The devitrifica-
tion caused by the continued low heat in the retorts will still further increase
the opacity caused by the phosphate of lime; and in some cases, where extreme
opacity is desirable, oxide of tin may be added in such proportions as may be
required. The mixture of materials herein given are for producing a white
opaque body or base for any description of colour that may be required. It is
well known the metallic oxides are generally employed for producing colored
glass; these substances are to bo used in combination with and added to the
materials herein-before mentioned previous to their fusion in the glass pot, and
in such proportions as will produce the required shade of color, and which we
need not further enter into, as they are well known, and this part of our
Invention having for its object only the giving of sufficient "body" or opacity
to such vitreous compounds as to render them fit for, use as pigments or paints
to be used with oil or water in the usual way. And further, with reference to
the proportions herein given for the formation of the vitreous base, a consider-
able alteration may be made therein, such as substituting potash for soda, all of
We
which is well known and understood by glass and vitreous color makers.
have therefore only given such proportions as we have found suitable, choosing
sulphate of soda as being a cheaper article than either carbonate of soda or
potash. In order to reduce these vitreous colors to a proper degree of fineness,
they should be first reduced to powder under edge stones, and then subjected
to a thorough grinding process with oil or water in a color mill; this grinding
should be perfectly effected, and for that purpose we prefer the apparatus or
mill herein last described.
And lastly, with regard to our apparatus or mill for grinding pigments or
paints, it is well known that the common color mill consists of a pair of stones,
the lower or bed stone being fixed, and the upper one having only a simple
rotatory motion on its own axis. The color is supplied by a central hopper, and
after passing between the stones, is received in a channel formed around the
bed stone. Each part of the upper stone, by simply revolving on its axis, passes
over a space upon the lower one in proportion to its distance from the centre,
and thus at every revolution of the stone, the parts nearest the centre will
move through a much less space than the outer ones, whereby the stones will
become unevenly worn, and their action upon each other rendered very imper-
fect, since the central parts, from the little wear to which they are subjected,
prevent the stones from coming in sufficiently close contact at their external
edges, which will wear away in proportion to the increase of their rubbing

page_text: action; and also the simple rotatory movement of the upper stone upon the
bed will cause it to wear into rings or ridges in consequence of the continued
passage of the parts over each other on the same lines. The furrows thus pro-
duced still further prevent the stones from coming properly in contact and
acting on the small particles of matter which they have to operate upon, and
thus not only does the rapid wearing of the stones take place, but the grinding
of the color is thereby rendered very imperfect. In order to avoid these defects
we construct a mill in the manner represented on Sheet B of the Drawings
hereunto annexed, where Figure 1 is a side elevation of the principal parts
of the apparatus, but as two pairs of stones are employed, one of the pairs are
shown in this Figure in section on the line A, B, of Figure 2; and Figure 2
is a plan of the color mill. a, a, is a stout wooden framing, which, with its
solid stop a¹ forms a sort of a table on which the two iron rings b, b, are
secured by their outer flanges c, c. These rings form a sort of annular
trough d for the reception of the ground color and terminate in spouts e, e,
in front of the mill. f, f, are inner flanges to the rings and support the bed
stones g, g, which are fitted therein, and are secured with plaister of Paris. At
each end of the frame a there is a vertical crank shaft h working in bearings i
at their lower ends, and in bearings ; at the upper ends. Each of these
shafts h, have a crank k formed on them; these cranks are in such a position
in the Drawings as not to be clearly distinguished as such, because the throws
are in a line with the shafts and further from the observer. These cranks k
are connected by a rod l provided with gibs and keys in the ordinary way The
upper ends of the shafts h, h, have half cranks m, m, fixed upon them, the
crank pins of which project vertically and terminate in conical apertures or,
sockets at n², n, on the swing frame n, which is made of bar iron and has two
circular openings at n', n¹. This frame n also serves the purpose of a con-
necting rod, by which.the motions of the two crank shafts are made to act in
concert, so that when motion is communicated by a strap from any first mover
to the drum o, the shaft on which the drum o is keyed will transmit its motion
to the other vertical shaft h by means of the cranks k, k, and connecting rod l
which are placed at right angles on their respective shafts. to the cranks m, m,
and thus mutually assist each other in passing their dead centres; this is still
further assisted by the fly wheel g, which regulates the working of the whole.
The upper stones r, r, are provided with hoppers 8, 8, and the under side of the
stones are chamfered out a little towards the centre, as shewn at r¹; in order
to facilitate the spreading of the color beneath them during their motion over
the surface of the bed stones, the stones r, r, are put into the openings n', n³,
of the swing frame n, where they fit loosely and bear their whole weight upon

page_text: the bed stone. Now when the materials in a semi-fluid state are put into the
hoppers, and the mill set in motion, the upper stones r, r, will be carried over
the surfaces of the bed stones by the frame n, which embraces them, but they
will not have a simple rotatory motion on their own axis, but their whole
bulk will move in a circle equal in diameter to the path of the cranks m, m,
and thus every part of their surface will move over an equal space, and every
scratch which tends to form grooves upon their surfaces will be obliterated by
the innumerable intersection of other scratches, since the position of the upper
stones are shifting their relative positions to the under ones at every part of
their excentric motion; and that a still further change of surface may take
place, the upper stones are allowed about half an inch play in the rings n³, n³,
so that they may roll round the interior of the rings, and as the diameter of the
stones are a little less than the diameter of the rings n², n, the stones will get
a rolling motion round the interior of the rings; this slow motion on their
own axis will add to the almost infinite changes of the grinding surfaces. The
motion imparted to the stones is identical with that used to grind sheets of plate
glass, whereby a very smooth and flat surface is obtained; stones employed to
grind colours will thus acquire a more perfect surface by use, and their extreme
flatness, whilo it admits of their action on a larger portion of color at once,
prevents the escape of it at the edges of the stones without being properly
ground; for it will be evident that the state of fineness to which the particles
of matter under operation are reduced must depend upon the closeness
with which the rubbing surfaces approach each other, and their freedom from
deep furrows, through which coarse particles.might escape without being
sufficiently ground.
Having thus described the nature of our Invention, we desire it to be
understood, that although we have herein shewn and explained many parts of
machinery or apparatus which are separately in use, we do not intend to
claim them separately as of our Invention, nor do we confine ourselves to the
details, so long as the peculiar character of any part of our Invention be
retained; but what we do claim is,―
First, the expressing of oils and oleaginous matters by forcing of the materials
to be operated upon by means of a plunger or piston into and through a
pervious vessel, whereby the resistance. offered to the passage of the matters
through the vessels causes the oil or oleaginous matters to be separated.
Secondly, we claim subjecting animal and vegetable matters containing oil
to the action of pressure in water, so as to cause the oils for the time to com-
bine with the water, and thus to facilitate the separation of oils from vegetable
animal matters containing them.

page_text: Thirdly, we claim the application of the metal bath, and of an air
bath, in the manufacture of varnishes, and also for boiling of oils, as herein
described.
Fourthly, we claim the withdrawing and condensing the volatile matters
from open vessels used in the manufacture of varnishes and in boiling
of oils.
Fifthly, we claim in the manufacture of pigments or paints the use of
phosphate of lime and oxide of tin for the purpose of giving body or opacity to
vitreous matters, in the manner herein-before described.
Sixthly, we claim in the manufacture of pigments or paints from vitreous
materials the devitrification thereof for the purpose of giving them a greater
body or opacity.
Seventhly, we claim the mode herein described of giving motion to the
grinding surfaces when grinding colors.
In witness whercof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Fourteenth day of November, in the year of our
Lord One thousand eight hundred and forty-nine.