IMPROVEMENTS IN WASHING AND SEPARATING MINERALS AND OTHER SUB- STANCES IN A GRANULAR OR PULVERULENT STATE
Year: 1855

page_text: LETTERS PATENT to Herbert Mack worth, of Clifton Wood House, Clifton,
in the County of Gloucester, Mining Engineer, for the Invention of
"IMPROVEMENTS IN WASHING AND SEPARATING MINERALS AND OTHER SUB-
STANCES IN A GRANULAR OR PULVERULENT STATE."
Sealed the 28th December 1855, and dated the 31st July 1855.
PROVISIONAL SPECIFICATION left by the said Herbert Mackworth at
the Office of the Commissioners of Patents, with his Petition, on the
31st July 1855.
I, HERBERT MACкWORTH, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN WASHING AND SEPARATING MINERALS AND OTHER
SUBSTANCES IN A GRANULAR OR PULVERULENT STATE" to be as follows:-
Granular substances vary so much in size, form, and weight, that the pre-
sent modes of treatment are not sufficient or adequately varied to separate or
clean them in the most effectual and economical manner.
Some minerals undergo from fourteen to one hundred washings and modes
of treatment, accomplished chiefly by manual labour; large quantities of
minerals are worthless, in consequence of the expense of preparing them by
the methods now in use, and a large proportion are very imperfectly cleaned
before they are used or smelted.
The improvements now proposed consist in applying currents of air, water,

page_text: and other fluids, and vibratory motion in such a manner as to take more
advantage than heretofore of the varying shapes and weights of the grains.
For this purpose I apply intermittent, or oscillating, or ascending currents of
air, which separate the smaller or lighter particles from the larger or heavier
I apply continuous currents of water or other fluid properly regulated,
having a direct or relative motion in horizontal or ascending directions, so as
to separate the grains or particles according to their specific gravity, and I also
employ such currents in apparatus so constructed as to cause the velocities of
the currents to vary from time to time and in different parts of their course.
By this means, grains which are raised or carried along by the currents in one
part of their course may be deposited in another part where the velocity of
the currents is less. I also effect the separation of the grains by percussion on
a table or web, by vibratory motion, and by the use of liquids of greater
specific gravity or more viscous than fresh water. In lieu of feeding or
working the apparatus by hand, I apply special machinery for that purpose,
and an inclined or horizontal endless frame or web for feeding or depositing
and separating or removing the materials.
These improvements may be used alone, or together with other processes
having a similar object, and they may be employed for ascertaining the actual
or relative specific gravity of the substances acted upon.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Herbert Mackworth in the Great Seal Patent Office on the
29th January 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HERBERT
MACKWORTH, of Clifton Wood House, Clifton, in the County of Gloucester,
Mining Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of July, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Herbert Mackworth, Her special licence that I, the said Herbert Mackworth,
my executors, administrators, and assigns, or such others as I, the said Herbert
Mackworth, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the

page_text: Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
WASHING AND SEPARATING MINERALS AND OTHER SUBSTANCES IN A GRANULAR OR
PULVERULENT STATE," upon the condition (amongst others) that I, the said
Herbert Mackworth, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Herbert Mackworth, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the accompanying Drawings, and
to the figures and letters marked thereon, that is to say:-
The Invention consists of six distinct processes for the separation of
granular or pulverulent minerals or substances, according to their shape, size,
or specific gravity.
The first process is the separation chiefly according to specific gravity, and
is applicable among other objects to the separation of the pyrites, shale, and
other matters which may be mixed with small coal.
The second process is effected on a percussion table or plate.
The third process is effected by an ascending current of air.
The fourth process is the separation according to the specific gravity, by the
employment of an ascending and properly regulated current of water.
The fifth process is the application of centrifugal motion, to produce an
ascending current of water and also a relative motion, to classify chiefly
according to specific gravity.
The sixth process is the removal of the grains by a revolving frame as they
descend in water or other fluid in the order of their specific gravities.
Each of these processes may be used separately or conjointly, the second
and third processes being in the latter case generally preparatory to the final
one, of separation by specific gravity.
FIRST PROCESS.

page_text: is usually to classify the grains according to size by screens and sieves, as has
long been done, preparatory to the common process of jigging coal and other
minerals. This classification can be effected by stationary sieves, or by sieves
fixed to a rocking or revolving frame, working either in air or water.
The
Figure 1, Sheet I. of the accompanying Drawings, exhibits an elevation,
Figure 2 a section, and Figure 3 a part plan, of the washing machinery.
The coal to be cleaned is deposited by an elevator or other means in regular
quantities in the uppermost of a series of centrifugal sieves, A1, A2, A³, which
may be one or more in number, according to the number of separating funnels
it is convenient to employ. In this Drawing three sieves are represented
inclosed in an iron or wooden case, with three apertures, and shoots to convey
the grains when classified or sized away to their corresponding funnels. Each
sieve or perforated plate is slightly curved upwards towards the outside, in
shape like a flat saucer. The lumps and grains falling on the upper sieve are
carried towards the circumference by the centrifugal motion.
The lumps
which will not pass through the upper sieve are thrown off by an aperture B
at the side of the case; they can then be either picked over by hand, or con-
ducted to a pair of crushing rollers, and thence again to the elevator.
pieces which will not pass through the second or third sieves are carried
round by the rapid revolutions of the sieve, and are thrown off at the side into
their respective shoots C and C. The finer particles which fall into the
bottom of the case are swept round by an arm into the lower shoot C³.
Sloping plates of sheet iron are placed between the sieves to direct the grains
falling through towards the centre of the sieve; the blows necessary to keep
the holes of the sieves clear can be conveniently given by attaching bullets by
short chains to the sides of the case; the same effect may be produced by a
current of air driven upwards through the sieves. The dimensions of the holes
in the sieves must be proportioned to the friability of the coal, so that a due
proportion of grains should be supplied to each of the water funnels; one
funnel, or other tube of convenient sectional shape, may be used to effect the
purification, but it is desirable to employ more in conjunction. The action of
the three funnels shown in the Drawing is similar, and it will therefore
suffice to explain the action of the central funnel, a section of which is shown
in Figure 2. The coal descending from the shoot enters the hopper D, which,
being-attached-to-the-vertical-axis-E, revolves slowly with it; the space down
to the perforated plate F' is thus filled, and the coal continues to enter from
the hopper only so fast as the coal is removed from below its lower orifice.
The short arm H, revolving and following immediately behind the hopper,
brings the surface of the coal in the water funnel to an uniform level.
A

page_text: continuous and regular current of water is made to pass in the direction of
the arrows by the revolution of the screw G, or any other convenient means.
The current of water is thus forced upwards through the perforated plate F¹,
and through every part of the coal above it, permeating the interstices of the
grains in every part, so as to keep them in a mobile state, or to raise or float
the particles of less specific gravity towards the surface. The pyrites and
shale being of greater specific gravity than the pure coal, arrange themselves
in the lower part of the tube next to the plate F¹; the coal which is brought
to the surface is swept by the curved arm or blade J up the surface of the
perforated plate K and over the edge of the funnel in to the shoot L, whence
it passes into a tram or other convenient receptacle. The shoot is traversed
by finely perforated plates and grooves, to allow the moisture in the grains to
drain off. The perforated plate or wire cloth K. offers a large surface for the
water to filter through, and may be very fine and of several thicknesses to
prevent any grains from penetrating into the circular chamber, by which the
current of water returns. By increasing the velocity of the current of water
or diminishing the number of holes in the plate F', and the other plates below
it, such as F, the rate of the current can be made such as to prevent any
particles of coal from sinking through. If any should pass through the upper
plate, they will be met by the current passing through the lower plates, and
may be carried up again through the upper plate. The size of the holes
and the velocity of the current should be greatest in the funnel where the
largest grains are treated. The shale and pyrites fall through these plates into
the chamber M; when they have collected in sufficient quantity they can be
removed by the door N, care being taken to close the valve O, so as not to
stop the working of the machine. This valve turns on an eccentric axis, and
being edged with vulcanized india-rubber, the pressure of the water tends to
keep it water-tight. When the communication has to be opened again with
the chamber, water must be supplied to the funnel by means of a hose or pipe.
The expenditure of water is therefore extremely small, and does not occur,
until it is becoming charged with earthy matters, in a state of solution or sus-
pension. In lieu of simple perforations in the plates F', F, short tubes may
be fixed by their upper extremities to the plates, or clusters of tubes alone may
be employed. An apparatus consisting of a number of such plates or tubes,
in which the current diminishes in velocity in ascending, may be used in con-
junction with revolving arms to clear each space for separating granular
substances, according to size and specific gravity conjointly. The velocity of
the current flowing into each funnel is regulated by the valve and handle
P, P. Although the current is shown as maintained by a screw, it can be

page_text: effected by a stream or head of water, or by a wheel or pump, or any other
suitable means of raising water.
A continuously ascending current of water may be employed in lieu of the
alternating up and down motion, known under the name of jigging, or in
combination with it, and it may be applied by means of perforations in the
bottom or sides to the various kinds of tables, troughs, boxes, tubs, sieves,
trays, fixed or endless webs or wire cloths, or other apparatus of similar kind
used in washing ores. The water may thus be supplied through the bottom,
and may then flow down instead of descending from a higher level. The appa-
ratus can be surrounded by an outer chest or case, or the water can be supplied
by means of a double bottom, or a flexible or other tube. By arranging
tubes so as to discharge at different points, the velocity or quantity of the
water flowing upwards in some parts of the apparatus can be made greater
than in other parts or be confined to them. By these means the classification
Many of the parts or arrange-
can be promoted, and manual labour saved.
ments herein-before described are not essential parts of the process, as many
of them may, according to local circumstances, be dispensed with; but as long
as the grains are supported above a perforated or other plate or wire cloth, or
series of tubes, and a current of water passes continuously upwards to keep them
in a state of mobility, acted upon by specific gravity, or to raise them so that
they can be removed by suitable means, it will come within the principle of
this Invention.
Although the process has been described particularly as applied to coal for
the sake of more complete illustration, it is also applicable for separating other
granular substances differing in specific gravity.
SECOND PROCESS.
The dressing or separation of mineral ores has been effected bitherto chiefly
by the action of water on the particles. In this the precise effect of the
water on the particles has not been sufficiently studied, and great, if not
insuperable, difficulties have consequently been experienced in substituting
machinery for manual labour. A large proportion of the minerals raised are
either thrown aside, lost in the preparation, or sent to be smelted in an
unnecessarily impure state from the amount and cost of manual labour
required in the existing modes of preparation. By allowing grains of the
same substance and equal in weight to descend in a considerable depth of still
water, it will be found that the water offers a greater retarding resistance to
the grains which are flat or oblong than to those which are spherical or cubical.
The effect of water on grains of different substances is frequently more due

page_text: th
to their shape than to their specific gravity, however complete may be the
previous classification by sieves, (and it is sometimes advantageous to use a
series of nine, varying from 1 inch to inch in the width of the holes.)
It is therefore desirable to classify the grains according to form. This may be
conveniently done in a somewhat similar manner to that used in obtaining
spherical shot, by allowing the grains to fall on the upper end of a table
having a longitudinal and lateral inclination, and assisting the descent of the
grains by percussion, or by a current of air or water passing over the surface
of the table. A machine for effecting a distinct classification of the grains
principally according to the shape is represented in Figures 4, 5, 6, of Sheet I.
The grains being deposited on a floor or in a trench A are carried forward by
the endless web or elevator B, B. The number of grains taken up by the
elevator can be regulated by the adjustable swinging board C, and are dis-
tributed over it from side to side by the battens or brushes D', D², D³. On
arriving at the further end of the elevator, the grains fall on to the upper end
of the percussion table E, E, E, E. The percussion table is suspended at its
lower extremity by chains catching on to hooks, which may be raised or
lowered so as to give it greater or less inclination, whilst, by increasing the
lengths of the chains without altering the inclination of the table, a greater
play or blow in the direction of its length can be obtained. The upper end of
the table is suspended by loose links F, F, from the bar G, G, which works
between the wooden slides H, H, and rests upon the cam wheels J, J. The
cams in revolving raise the table, and allow it to fall with a concussion in a
vertical direction, and when required at the same time to strike against the
posts at the bottom in the direction of its length; the concussion serves
also to clear the elevator of grains. The supply of grains can be stopped by
allowing the regulating board C to drop on to the web, and when the grains
have been sufficiently separated by percussion, the centre part of the percussion
table which turns on the pivot K, K, is opened into the position indicated by
the dotted lines. The table by continuing its motion deposits the grains into
the chambers L, L, and through the opening at the bottom end into L³.
When water is employed in the chest, the current passing over the lower end
whilst the table is raised. and over the upper end as it falls, assists the grains
in descending the slope. The effect of the table is further enhanced by
covering it with finely perforated plates or wire gauze through which the water
passes freely. For convenience in removing the grains from the bottom of the
chest, three endless webs M1, M2, M3, are employed. By turning the winch
handle N, the grains deposited on the webs are raised, so as to fall over the side
into separate receptacles. Although the principal object of this process is to

page_text: When several minerals or substances in a granular or pulverulent state
cannot be separated by one operation, it is, as a general rule, desirable to vary
the processes as much as possible. By subjecting them to the action of a
current of air after having passed through the sieves or perforated plates, the
rounder or denser particles may be partially separated from the rest. One of
the modes of effecting this is represented in Figures 7 and 8, which exhibit a
longitudinal section and an end elevation of the machine. A current of air is
passed through the machine in the direction of the arrows, either by means of
a fan, steam jet, or ventilating machine, or by connecting it with a chimney at
A. The grains, after being deposited in the trough B, are supplied in regular
quantity by the grooved roller C, and fall through the aperture D, which can
be closed to the requisite degree by the slide E. The grains in falling are
subjected to the action of an ascensional current of air, which, acting upon
them in proportion to their various degrees of resistance, transports them and
classifies them accordingly into the divisions F1, F2, F3, F', F. The apertures
in the plate G, G, can be so arranged as to give the most rapid current along
the side from which the grains are allowed to fall, and the average velocity
of the current can be decreased towards the upper part by increasing the
sectional area of the tube or vessel. By closing some of the holes G, G, the
velocity of the current may be confined to the side next the compartments
F, F, and F, or it may be made uniform in velocity. In operating upon the
finer description of grains, it will be convenient to connect the air passage with
a large chamber at A, so as to allow the fine dust to subside. The same
effect may be produced by stopping the pulley II, which gives motion to the
feeding roller C, at short intervals, and by closing the door J, so as to stop
the current of air. The collection of the finer grains may be assisted by
allowing condensed steam to mix with the air after it has passed through the
apertures G, G. The velocity of any current of air can be rendered more
uniform by a regulator at K. One of the simplest forms of such a regulator is
shewn in the Drawing.
A light plate turns freely on a pivot at the upper end, and is-suspended-by
a spiral spring or clastic caoutchouc cord at the other extremity. As the
velocity of the current increases, the increased pressure tends to close the regu-
lator. The length of the cord can be adjusted to the greater or less velocities
required for large or small grains. The grains which have collected in the

page_text: chambers F, F, F³, F, F, can be removed by sliding or other doors, such as
L, L. The number of chambers which it is convenient to use in classifying,
whether more or less than five, depends upon the material to be operated
upon. When the grains have been well classified according to size, three
chambers will usually suffice. For the partial separation of one mineral
a simpler apparatus will suffice. Water may be advantageously used in the
same manner as the air in a machine of the general form here shown, provided
the machine be properly connected with water channels made water-tight, and
the feeding trough be carried up above the level of the water. The current
can be propelled through at the required velocities by the means elsewhere
described; the separation of the grains will be more complete in relation to
their specific gravity than when air is employed.
FOURTH PROCESS.
If a current of water be made to flow at a sufficient and regular velocity
upwards through a glass tube which is largest at the top, and grains of different
substances but of equal size, as, for example, galena, iron pyrites, and quartz,
be thrown in, they will descend until they reach a part of the current just rapid
enough to support them, and they will be found to be separated by considerable
intervals, the galena being the lowest and the quartz the highest. In this
manner the relative specific gravity of bodies of the same size and shape can
be found.
If openings be made in the sides of the tube similar to the chambers
described in the last process, the grains will find their way to them and be
obtained separately. The same object, the separation of granular substances,
can be advantageously effected by operating in several tubes in lieu of one, as
shewn in the Figures 9 and 10, which represent the part elevation, and part
section, and the end elevation, respectively, of the machine. The water is
caused to circulate through the tubes in the direction of the arrows by means
of the screw A, or other suitable means. The velocity of the current is
regulated by the valve B; this valve is opened or shut by means of a lever at
right angles to it, and a rod passing up through the hollow metal float C. A
screw on the top of the rod adjusts it for the velocity required. As the
velocity of the current increases beyond the regulated amount, the water in
the tube D rises and raises the float and partially closes the valve B. The
grains are supplied to the hopper E by an endless band, elevator, or other
suitable means. The axis F, provided with fly arms at the bottom and worked
by the current, discharges the funnel at a rate proportioned to the velocity of
the current. The grains may also be conveniently fed by a trough and

page_text: grooved roller, as described in the last process, as well as other suitable
means. On arriving at the bottom of the first tube, the grains are then
subjected in the tube G to the action of an ascending current of water, which
should be sufficiently rapid to carry up and over into the next tube all but the
grains of the heaviest substances to be separated. In the tube H the action
is similar, but, being considerably larger in the sectional area, the current is less
rapid, and grains next in order of specific gravity will remain there, whilst the
grains of less weight are carried up into the cistern J. The tubes G and EL
increase slightly in diameter upwards to allow for slight differences in the size
and shape of the grains which do not pass over, for the round or cubical par-
ticles have a greater tendency to remain at the bottom, and the flattened or
elongated to occupy a superior position in the slower part of the current. The
grains which remain near the bottom descend through the holes K', K², into
the cisterns L', 12. To prevent the accumulation of grains in the lowest part
of the tubes, the elastic plates M', M³, can be forced downwards by screws
so as to deflect the current of water downwards. On commencing to work,
the holes K' and K² are kept closed by the elastic plates N1, N2, and when the
machine is in full motion the screw is turned, so as to open a small passage
to the holes, and cause a dead water behind the plate, and to facilitate the
removal of the grains. To remove the grains from the cisterns, the doors 0, 0,
are opened; but in order that the working of the machine may not be stopped,
the valves P, P, are first closed, which retain the water and leave a space
for the accumulation of grains. These valves are mounted eccentrically, so that
the pressure of the water tends to keep them closed. The grains which are
carried up into the cistern J fall into the bottom, and are raised by the wheel
Q, Q, so as to fall into the shoot R. This wheel may be worked by the current
by means of vanes, like those of a common smoke jack, about its centre, or by
gearing worked independently of the current. Other forms of elevators may
be employed for emptying the grains which reach the highest cistern. The
tube S, open at the top, is for the purpose of allowing bubbles of air to escape.
The machine can be employed with either one, two, or more ascensional tubes,
of equal or different lengths, or one above the other, and each tube may be
either single or divided, or oval in sectional form. A coating of pitch or other
suitable material on the inner surfaces of the tubes may be used to reduce the
friction of the water against the side. If the tube is made flat-sided and
sloped, the grains will ascend along the slope, and a greater time be given for
separation. The currents of water may be produced by a stream or a head of
water as well as by a machine.

page_text: The classification of granular substances, according to specific gravity, by a
current of water, having an ascending as well as a relative motion, is repre-
sented in Figures 11 and 12, which represent the plan and section of the
machine.
The basin A, A, A, open at the bottom B, B, is made to revolve in water
with considerable velocity; the curved blades C, C, attached to the bottom of the
basin, cause the water to flow through B, up the slope of the basin, and over the
lip or edge on to the finely perforated plate or wire gauze D, D, which it filters
through, returning to the aperture B. The mineral to be separated or classified
is fed by a band or elevator working on the pulley E, or by other suitable
means, into the fixed hopper F. G, G, is a circular trough revolving with the
basin; there are six holes in it to correspond with each interval between the
curved blades. As each hole comes under the hopper, some of the grains fall
through into the current which is rushing up the surface of the basin. The
lighter particles are carried up by the current, and deposited on the perforated
plate D, D, whilst those of greater specific gravity descend the slope of the
basin into the chamber H.
The grains which fall on to the perforated plate D, D, are driven over
the edge of the cistern by the revolution of the sloping bars K, K, and, by
means of the shoots inclining each way, are collected at the angles L, L,
for subsequent removal. The grains which collect in the chamber H can
be drawn off by the cock M. Water will have to be supplied to the
cistern during their removal, but if the chamber be fitted with an inner
and outer valve, the grains may be removed without in any way inter-
fering with the action of the machine. The angles on the convex side of
the curved blades may be advantageously rounded off by a curved plate or
block of wood, to prevent the grains from lodging in them, and partly escaping
the action of the water.
PROCESS No. 6.
The application of machinery for feeding granular substances, removing and
separating them as they descend in water or other liquids in the order of their
specific gravities, is shewn in Figures 13 and 14, Sheet II., which exhibit an
elevation and plan of the machine. Figure 15 is a vertical section; and
Figures 16 and 17, transverse sections along the dotted lines B, B, and C, C.
The grains are first supplied into the circular trough or hopper (a), where they
are levelled by the revolving distributors (b, b).

page_text: The cylinder containing water is divided into compartments (c, c, c, c, c, c.)
In the bottom of the hopper are six holes (d, d, d, d, d, d,) exactly over the
centre of these compartments, each of which is closed by a spring latch and
plate, one of which is shown by dotted lines at (e). The arm (f) in its revo-
lution presses against this latch, and uncovers for a moment the hole, so as
to allow a quantity of the grains to fall into and descend through the water to
the bottom of the cylinder c. The grains in falling through the still water
have the same relative motion as when acted upon in previous processes by a
current of water.
The revolving frame (9) at the bottom of the cylinder is fixed to the same
axis as the arm (f), and is divided into six compartments, in each of which is
a tray with curved loops (h) for lifting it up and removing it. For the sake of
illustration, suppose that it is wished to separate galena, copper pyrites, and
quartz, and that the operation is considered in relation to one compartment
only the revolving frame is worked at such a velocity as that the tray for
galena shall be under the compartment as the galena reaches the bottom; the
next trays following in the revolution receive the pyrites, and those following
after receive the quartz. The frame should not revolve so rapidly as that
there should be much danger of the grains of quartz falling into the tray for
galena as the latter completes its revolution. The arm f can be shifted in
different positions, so that the openings of the spring latch shall correspond
more exactly with the position and velocity of the tray intended to receive the
grains of greatest specific gravity. By leaving out several of the last of
the trays, the grains of the least specific gravity may be allowed to fall directly
into the recess (j), from which they can be removed by the valve or cock at (k).
The trays can be drawn up to the top of the cylinder and emptied. If six
recesses were made in lieu of one at (7) to correspond with the six compart-
ments, and valves were fitted to the bottoms of the trays, then, by stopping
these over their appropriate recesses and opening them, the contents might be
discharged by means of the recesses in lieu of lifting out the trays. The
divisions of the compartments in lieu of being vertical can be made to slope,
and the grains allowed to fall so as to descend the slope, by which means their
descent will be retarded in proportion to their shape and size, and the classifi-
cation of some substances promoted. Again, liquids of greater specific gravity
than fresh water, such as salt water or other solutions, can be employed to
retard the motion, especially of the particles of the least specific gravity amongst
those to be separated. When an ascending current of water is employed in
this machine, a central or other tubes will provide for the entrance and
exit of the current at the top and bottom of each compartment. To secure

page_text: uniformity of velocity in the revolving frame, its motion can be communicated
from a water wheel working by a head of regulated height, or a suitable
governor can be used.
The six processes above described may be used separately or conjointly in
connection with part or parts of the machines heretofore in use, and they can
be so arranged, when local circumstances are favorable, that the whole opera-
tion of separating granular substances, including the classification by size, can
be effected without the intervention of manual labour as part of the process.
Although, for the sake of explanation and illustration, particular parts and
arrangements of machines have been described, I do not intend to confine the
Invention to the employment of such machines or parts as long as any of
the following improvements is or are retained, and which I claim as my
Invention
Firstly, the classification or separation of granular or pulverulent substances,
by means of a current or currents of water or other liquids continuously
ascending through the particles, so as to keep them in a state of partial sus-
pension or mobility, in which they arrange themselves according to specific
gravity, and so that they can be separated and removed by continuously acting
machinery, as herein-before described.
Secondly, the application of perforated plates, or wire cloth, or a cluster of
short tubes in apparatus constructed for the classification or separation of
granular or pulverulent substances, according to their shape or specific gravity,
by means of continuously ascending currents of water or other liquid, as herein-
before described.
Thirdly, the classification or separation, according to their shape or specific
gravity, of granular or pulverulent substances (which have been previously
classified according to size) by means of currents of air or water, or other fluid
continuously ascending in a tube or tubes, and so arranged and applied as to
diminish in velocity as they ascend, or on one side of the tube, as herein-before
described.
Fourthly, the construction and application of an inclined perforated or other
percussion or oscillating table, immersed in air or water, and with or without a
moveable leaf, and having an up and down as well as an end motion, as herein-
before described in reference to Figures 4, 5, and 6, to assist in the classification
of minerals in a granular or pulverulent state.
Fifthly, the classification or separation of minerals in a granular or pul-
verulent state by a regulated continuous or intermittent ascending current of
air, as herein-before described.
Sixthly, the application of an ascending current of water, having at the same

page_text: time a relative motion over a centrifugal plate with curved blades, for the pur-
pose of classifying or separating granular substances, as herein-before described
in reference to Figures 11 and 12.
Seventhly, the construction and application of a revolving frame with trays
or compartments, for the purpose of receiving and classifying granular and
pulverulent substances as they descend in liquids in a state of rest or of
ascending motion, as herein-before described in reference to Figures 13, 14,
15, 16, and 17.
Eighthly, the construction and application of continuously acting machinery
or apparatus of the various constructions herein-before described in reference
to the accompanying Drawings for separating and classifying substances in a
granular or pulverulent state.
In witness whereof, I, the said Herbert Mackworth, have hereunto set
my hand and seal, this Twenty-sixth day of January, in the year of our
Lord One thousand eight hundred and fifty-six.
HERBERT MACKWORTH. (L.S.)