IMPROVEMENTS IN STEAM AND OTHER MOTIVE-POWER ENGINES
Year: 1882

page_text: LETTERS PATENT to Thomas Hancock of Wolverhampton in the County of
Stafford, Mechanical Draughtsman for an Invention of "IMPROVEMENTS IN
STEAM AND OTHER MOTIVE-POWER ENGINES
"
PROVISIONAL SPECIFICATION left by the said Thomas Hancock at the
Office of the Commissioners of Patents on the 28th December 1882.
THOMAS HANCOCK, of Wolverhampton in the County of Stafford, mechanical
draughtsman, "IMPROVEMENTS IN STEAM AND OTHER MOTIVE POWER ENGINES'
""
My improvements relate, first, to steam and other motive power engines such as
pneumatic and hydraulic, not required to work expansively; second, to the means
of effecting the rapid cut-off of the steam or other elastic motor such as compressed
air employed in steam and other motive power engines constructed otherwise
according to the first part of my invention; and, third, to the means of regulating
and controlling the point at which such cut-off takes place, such regulation and
control being effected either by hand or automatically by means of governors.
I will describe the first part of my invention in relation to a steam engine, after
which its application to an engine driven by other elastic motor or by hydraulic
pressure will be readily understood.
The steam chest is cylindrical with its axis in a direction across the main
cylinder, and is divided in the middle so as to form two separate chests.
One end
of each steam chest is of a less diameter than the other end, and a piston valve is
fitted to work one in each of such parts of different diameter in each steam chest.
The two valves in one steam chest are formed in one piece or rigidly connected so
as to move together. For the sake of clearness of description it may be stated
that both steam chests with their accompanying valves, ports and any connections
with the cylinder are exactly alike in every respect. I will therefor proceed to
describe one of such chests with its valves and connections complete and the whole
of this part of the invention will then be readily understood. One steam chest
with its valves and ports acts to supply steam to one side of the main piston only
and to exhaust it from the other. Each of the main cylinder ports is connected
with the steam chest, one by a port into the part of lesser diameter to act as the
гр
"

page_text: steam port for one end of the cylinder, and the other by a port into the part of
larger diameter to act as the exhaust port from the other end of the cylinder. The
steam inlet and the exhaust outlet are placed respectively in the same position
lengthways of the chest as the steam and exhaust ports, aforesaid. When the
valves are moved in the direction from the larger to the smaller end of the chest
they cover and therefore close both the steam and exhaust ports and steam inlet
and exhaust outlet, and when moved in the other direction they open such ports
and inlet and outlet, the exhaust port and outlet being in that case between the
two valves, and the steain port and inlet outside the smaller valve. As the main
piston reaches the other end of its stroke it passes over and uncovers a small port
communicating between the cylinder and the back of the larger valve. The area
of this valve being greater than that of the other valve, which has been kept back
by the pressure of the steam, both the valves are driven forward by steam issuing
from the cylinder and the ports are closed. A ring working in the steam chest the
necessary distance back from the larger valve, and connected therewith, closes
the small port from, the cylinder as the valves close. About the same time that
the valves in one chest are closed the valves in the other chest are opened in a
corresponding manner by means of a small port communicating with the steam
chest at the outer face of the smaller or steam valve, thus driving both valves
open. The steam pressure remaining at the back of the larger valve, after the
valves have been closed in one chest, is relieved immediately the valves in the other
chest are opened by means of a port which communicates between the space con-
taining such pressure and the space in the other steam chest which is open to the
exhaust. This communication is. again. cut-off by, the closing of the one set of
valves; but the space at the back of the other set of valves is thus left free from
pressure and the valves are consequently readily driven open by the steam acting
at the outer end of the smaller valve as the piston again reaches the former end of
its stroke. To start the engine the valves may be moved by hand, or any suitable
means may be adopted.
E The above described arrangement is suitable in the case of direct-acting Engines
for pumping and other purposes and also in the case of engines working with a
rotative motion.
When an engine driven by steam or other elastic motor is required to work
expansively, nearly the same arrangement as before described is employed, but
there are certain additions thereto and modifications therein, which I will now
proceed to describe, and which, by themselves and in combination with the
arrangements before described, constitute the second part of my invention.
ر
Each steam chest has added to the part of smaller diameter a part of smallest
diameter and in this latter part are situated the steam port and inlet instead of in
the part of smaller diameter. The steam valve in this case is an addition to the
valve before described as within the part of smaller diameter, and is formed of
different diameters, one part working within the smaller diameter part of chest
and the other in the smallest diameter part. The steam valve slides on a stalk
prolonged from the other valves. Presuming now that the ports are open on
account of the valves being moved in the direction towards the larger end of the
chest and that the main piston is travelling along the cylinder, then steam is
admitted from the cylinder at any desired distance of the piston's travel into a
small port communicating therefrom to between the first-described valve of smaller
diameter and the larger face of the steam valve, and on account of the difference
in the areas of the two faces of the steam valve such valve is driven forward
against the pressure of steam at its other face and thus closes the steam port and
inlet leaving the other valves in position and the exhaust consequently open. The
exhaust port is closed near the end of the stroke in the manner already explained.
The steam valve is opened in the manner hereinbefore described for opening the
other valves, and as it is opened it forces back the other valves and opens the
exhaust also. The small port for supplying steam to close the steam valve is closed
by the smaller valve first described, and the steam pressure remaining between
i

page_text: such valve and the steam valve is relieved in the same manner as the pressure at
the outer side of the largest valve.
In order to regulate and control the degree of expansion in an engine constructed
as described under my second division, the object of which is the purpose of the third
part of my invention, a number of small holes or ports are formed at increasing
distances from one end of the cylinder so as to communicate between the cylinder and
a cylindrical passage running parallel with the cylinder. A small port communicates
between the cylindrical passage and the port, aforesaid, which supplies steam to
close the steam valve, this latter port having in this case no communication with
the cylinder except through the cylindrical passage and holes from the cylinder
thereto. Within the cylindrical passage is fitted accurately a hollow cylinder,
having a number of holes through one side thereof corresponding with those from
the cylinder into the cylindrical passage, but spaced apart so that in moving the
hollow cylinder endways only one hole at a time from the cylinder coincides with
a hole in the hollow cylinder, and so that during such an operation each hole from
the cylinder is opened, or made to coincide with a hole in the hollow cylinder, in
succession. The hollow cylinder has a long port through one side of it which is
always in communication with the port to supply steam for closing the steam
valve. It is evident therefore that the travel of the piston before it uncovers a
port in communication with the back of the steam valve will vary according to the
endway position of the hollow cylinder. Two such hollow cylinders, passages and
sets of ports will be required, one for either end of the cylinder; and both the
hollow cylinders may be moved by hand to vary the expansion, or they may be
moved by governors driven from the rotative motion of the engine, or by the
pressure of water as in the case of a direct-acting pumping engine, or by any
The
convenient arrangement of governor, thus giving an automatic variation.
holes in the hollow cylinders may, if desired, be arranged for such cylinders to bé
moved radially instead of endways.
I have described the second and third part of my invention as applied to
steam engine but the application to other engines worked by other elastic motor
will be obvious.
Some of the smaller ports, such as those for relieving pressure as described,
may be advantageously formed of piping, thus reducing the complication of the
castings.
According to the above described invention, the most convenient arrangement
for the main cylinder ports is to bifurcate them at the steam chest end and place
one branch of such bifurcation of one port between the two branches of the other,
and this arrangement of ports may be adopted in other analogous cases.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Hancock in the Great Seal Patent Office on the 27th June
1883.
THOMAS HANCOCK, of Wolverhampton in the County of Stafford, mechanical
draughtsman, "IMPROVEMENTS IN STEAM AND OTHER MOTIVE POWER ENGINES
"
My improvements relate, first, to steam and other elastic motive-power engines
not required to work expansively; second to the means of effecting the rapid cut-
off of the steam or other elastic motor (such as compressed air) employed in steam
and other motive-power engines constructed otherwise according to the first part
of my invention, and, third, to the means of regulating and controlling the point
at which such cut-off takes place, such regulation and control being effected either
by hand or automatically by means of governors.
I have illustrated the invention upon the accompanying drawings, as applied to
steam engines, and the description of such illustrations will relate specially therefor
to this class of motive-power engines, but upon a due consideration of such
illustrations and description the application of the invention to engines driven by
other elastic motor will be readily understood.
I have found it more convenient for the sake of simplicity in illustrations and
description to describe the second and third parts of this invention before
proceeding to a description of the first part thereof.
The second and third parts of my invention are illustrated by the drawings on
sheets 1 to 4 inclusive, of which figure 1 is a section taken transversely through
the centre of the engine cylinder, and consequently (as will be presently understood)
longitudinally through the steam chest. Figure 2 is a longitudinal section through
the centre of the engine cylinder, being also a transverse section through the steam-
chest. Figure 3 is a view looking on the top of the cylinder with the steam-chest
removed. Figure 4 is a view looking on the top of the steam-chest. The same
letters of reference occurring upon any two or more of these views, and also of
the views figures 5 and 6 presently explained, indicate corresponding parts. A is
the engine cylinder, B B the steam-chest which is also cylindrical and has its axis
in a direction across the engine cylinder. The steam-chest B B is divided in the
middle by a diaphragm C so as to form two separate chests. Each steam-chest
consists of three parts, those of the right-hand chest being marked D E and F and
those in the left-hand chest being marked D' E and F, the parts E and E¹ being
of a smaller diameter than the parts D and D' and the parts F and F of a smaller
diameter than the parts E and E. The valves and ports of one steam-chest
correspond exactly to those of the other. One steam-chest, with its valves and
ports, acts to supply steam to one side of the engine piston only and to exhaust it
from the other. G is the steam branch which is bifurcated to supply steam to
the inner ends of both chests in the position shewn. H is the steam port from
the right hand chest into the cylinder passage I, K the exhaust port from the
cylinder passage L into the chest and M (shewn by dotted lines figure 1) the
exhaust port from the chest to the exhaust branch N. A section of the exhaust
port, which runs along the side of each chest to the branch N at the centre of the
double chest, is clearly shewn at figure 2, and the exhaust port from each chest is
shewn by dotted lines figure 1 and also by dotted lines figure 4 as is also the
branch with which they communicate. The exhaust opening M' however from the
left-hand chest is shewn by full lines figure 1. The arrangement of the cylinder
passages is clearly shewn by figure 3; it will be seen that the cylinder passage I is
bifurcated to communicate with both the steam port H and the exhaust port K¹

page_text: for supplying and exhausting steam to and from the one end of the cylinder, and
that the other passage L is similarly bifurcated to communicate with both the steam
port H' and exhaust port K for supplying and exhausting steam to and from the
other end of the cylinder. a and b are pistons formed together in one piece with
the space c between them, the piston a fitting within the part F of the steam-chest
and the piston b fitting in the part E of the chest; these two pistons are connected
to a spindle d which passes out through the end of the chest and terminates in a
handle O. e and fare also two pistons formed together in one piece upon a hollow
spindle g which passes out also through the end of the steam-chest. The pistons e
and f have a space h between them and fit respectively in the parts E and D of the
steam-chest. j is a ring of metal fitting in the part D of the steam-chest and
connected by suitable arms to the hollow spindle g. The hollow spindle g is
capable of sliding upon the spindle d and proper packing joints are made as shewn
where the spindle d passes out through the end of the spindle g and where the
latter passes out through the end of the chest. The spindle g is connected to the
pistons a and b by means of a cotter k in addition to the inner counter sunk head
of the spindle, as shewn, which latter forms a steam tight joint at the end of the
piston. The parts in the left-hand chest and ports corresponding to those lettered
a, b, c etc. in the right-hand chest and ports are lettered a' b¹ c¹ etc.
The engine will start immediately steam is turned on to the branch G with the
pistons in the position in which they are shewn in their respective chests. The
steam flowing direct through the port H and passage L to one side of the engine
piston, and the exhaust flowing out from the other side of the piston through the
passage I, port K¹ and exit M When the engine piston has travelled to a point
in its stroke at which the steam is to be cut off a communication is opened (by
means which will be presently explained) between the steam acting at the back of
such piston and a small passage n in the steam-chest through which steam is
admitted against the outer face of the piston b', and this pressure counterbalancing
the pressure at the inner face of the piston al (on account of the larger area of the
piston 6¹) forces back the pistons a and b into the position in which the corre-
sponding pistons a and b are shewn in the right-hand chest, closing the steam
port Hand thus cutting off the steam from the engine piston, but leaving the
pistons e¹ and f¹ and ring j¹ in their outward position. I may here explain that
in this and other instances where the space at the back of the engine piston is
referred to it means that side of the piston on which the steam pressure is at the
moment acting. Immediately before the engine piston reaches the end of its stroke
a small passage o³ (figure 2) in the interior face of the cylinder is placed in com-
munication with the steam at the back of the engine piston, and this passage
communicating by means of a small pipe s¹ (partially shewn at figure 1), or other
passage, with the small port o¹ in the part D' of the steam-chest allows steam to
pass from the cylinder to the outer face of the piston f¹ driving back such piston
and also the piston e¹ and the ring j¹ into the position in which the corresponding
pistons e and f and ring jare shewn in the right-hand chest, when the exhaust
port K¹ thus becomes closed the ring covering the small port o¹ and closing the;
communication therethrough from the cylinder. The piston f1 is of a larger
diameter than the piston e¹ so that the pressure on the outer face of the piston fl
will counterbalance the pressure on the inner face of the piston e'. The steam has
free passage between the arms of the ring j¹ and thus presses against the end of the
chest. As the piston e¹ advances against the piston b¹ the steam remaining in the
space t¹ between the two pistons escapes along a passage p¹, slightly recessed in the
cylindrical face of the chest, into the small port n'. The port n¹ together with the.
recessed passage pl is completely closed as the piston el travels inwards (see the
position of the corresponding piston e in the right-hand chest). Momentarily after.
the inward movement of the pistons e' and f' the whole of the pistons and the
ring in the right-hand chest are moved back into the position in which the corre-
sponding pistons and ring in the left-hand chest are shewn on the drawing. This
movement is effected in the following manner:-a small port q² (figure 2) is

page_text: connected by means of a pipe or other passage with the small port q in the part F
of the steam-chest, by which means steam from the back of the engine piston is
admitted between the inner face of the piston a and the diaphragm C thus driving
back all the pistons in the right-hand steam-chest together with the ring j. It will
be seen that after the piston a has been partially driven back, by the steam entering
through the small port q, the steam from the branch G rushing in behind the
piston a rapidly drives it and the other pistons and ring into the position in which
the corresponding pistons and ring are shewn in the other steam-chest. As the
main piston travels towards the opposite end of its stroke the pistons a and b are
forced back in the manner as before described with reference to the pistons a'
and 61, to cut off the steam, and the pistons e and f and the ring ; are forced back
also immediately before the end of the stroke by corresponding means to those
employed in the case of the pistons e¹ and f¹ and ring in the left-hand chest ;
and momentarily thereafter the whole of the pistons in the left-hand chest together
with the ring jare forced outwards automatically by corresponding means to those
described for moving back the pistons in the right-hand chest, that is say the small
port q³ figure 2 is connected with the small port q¹ for supplying steam between
the diaphragm C and the piston a'. It will be seen that on the back of each
piston a and a¹ a shallow boss projects so as to leave a small space for the reception
of steam pressure between the diaphragm C and each of such pistons, respectively.
It should be explained also that in order to get rid of the pressure of steam left
within the space between the piston f and the outer end of the steam-chest a piper
communicates between such space and the space between the pistons e¹ and fi in
the left-hand chest, when such latter pistons are in the position shewn, and thus
there is direct communication with the exhaust passage from the left-hand chest.
This communication is cut off by the piston f as such piston arrives at the outward
end of its stroke. A corresponding pipe effects the same purpose in relation to
the pistons in the left-hand chest as does the pipe to those in the right-hand
chest. The spindles d d and g g' are carried through the ends of the chest, as
shewn, so that the piston valves may be moved by hand to start the engine if
necessary, or to reverse it, and in the case of large engines the spindles may be
connected to suitable gearing for handling them the more readily. The outward
motion of the pistons in the respective chests is stopped by the collars m and m¹.
It will be seen that according to this invention the ports are opened and closed
instantaneously.
An exhaust port may be closed as early in the stroke as desired after the closing
of the steam port in the same chest or simultaneously therewith, as will be readily
understood, and the steam port may be opened as early as may be desired after the
closing of the exhaust for the corresponding side of the engine piston.
The means for supplying steam to the small port n of the right-hand steam-chest,
for closing the pistons a and b, may consist simply of a small pipe or other passage
communicating between the interior of the cylinder, at any point of the engine
piston's stroke at which steam is desired to be cut off, and the said port n, a corre-
sponding arrangement being employed for supplying the small port n'. In such
case however the point of cut-off will remain constant, and the arrangements
described according to the third part of this invention are employed for regulating
the point of cut-off.
and 2,
The drawings on sheet 4, as also parts of views shown by figures
illustrate mechanism employed, according to the third part of this invention, for
controlling the degree of expansion in the engine cylinder A. Figure 5 is a
horizontal section on line xx of figure 1. A¹ B¹ are tubes fitting within hollow
cylindrical parts formed longitudinally within the main cylinder casting as shewn
clearly in transverse. section by figure 1. The tubes A¹ and B' are capable of
being moved endways within their respective hollow cylinders. The tube A¹
controls the expansion when the engine piston is travelling in the direction
indicated by the arrow A2, and the tube B' controls the expansion when the engine
piston is travelling in the direction indicated by the arrow B³. These tubes being

page_text: constructed and operating similarly to one another, a description of the tube A¹
only will be sufficient. 1, 2, 3 etc. are openings formed through the side of the
tube A, and 1*, 2*, 3* etc. are openings formed from the hollow cylinder in which
the tube A' works to the main cylinder A. P is a port or opening from the hollow
cylinder last-mentioned and communicates by means of a small pipe or other
passage with the small port n through which, as before stated, steam passes to close
the pistons a and b (figure 1) to cut off the steam from the main cylinder. Qis a
long opening through the side of the tube A¹, its length and position being such
that it is always in communication with the port P in any position in which the
tube A' can be placed by the mechanism provided to give it an end way movement.
In the position in which the tube is shewn by figure 5 it will be seen that the
opening 3 through the side of the tube A' coincides with the opening 3ª from the
main cylinder A, and that therefor there is a direct cominunication between the
interior of the main cylinder A and the port n (figure 1) through the opening 3*,
the opening 3, the tube A¹, the openings Q and P and the pipe or other passage
connecting the port P with the port n. When therefor the engine piston passes
the opening 3ª the steam at the back of the piston immediately rushes through the
communication just described, and closes the pistons a and b and thus cuts off the
steam within the main cylinder A. Now the openings 1, 2, 3 etc. are arranged in
relation to the openings 1 2 3 etc., respectively, in such a manner, as shewn, that
one, and only one of the openings 1, 2, 3 etc. is always in communication either in
whole or in part with one of the openings 1, 2, 3 etc. in whatever endway
position the tube A' may be placed, and also as that the further the tube A' is
moved in the direction indicated by the arrow A³ so will such communication
take place at an opening from the cylinder nearer to the beginning of the
piston's stroke, and vice versa, the possible variation of expansion being of course
limited by the number of openings from the cylinder. The tube B' is shewn to be
constructed to move in the same absolute direction as the tube A¹ to produce a
corresponding effect on the expansion as the engine piston is moving in the opposite
direction, but both the tubes may of course be constructed to move in the same
relative direction to the motion of the piston, if desired. The tubes A and B are
closed by diaphragms u u etc. and pass through packings in the cylinder lids as
shewn, and their back ends are connected to a cross bar R R which carries a nut S.
The
Through this nut S works a screw T having a hand wheel U on its outer end.
screw T is carried in a boss V at its inner end rigidly fixed by means of a shank W
to the cylinder. The screw T is free to turn in the boss V but is prevented by means
of collars from moving endways therein. By means of this screw T and handle U
the tubes A and B₁ are placed in position to suit any required degree of
expansion.
If the expansion is desired to vary automatically the screw arrangement
described is dispensed with and the tubes A' and B' are connected to the governor
gearing as will be readily understood.
The holes in the tubes, may, if desired, be arranged for the tubes to be moved
radially instead of endways.
The various small ports illustrated throughout the different views have been
shewn in position specially with a view to clearness and simplicity of illustration,
and their position may of course be varied as may be found most convenient.
I have also omitted to illustrate some of the piping connecting the small ports,
in order to avoid unnecessary views and complication in the drawings, but these
details will be readily understood from the foregoing description.
The improvements already described are applicable to engines worked by steam
or other elastic motive-power working with an ordinary rotative motion, or direct-
acting as in the case of actuating pumps, but in such latter case the engine piston
must of course be cushioned at each end of the stroke in the usual manner, and if
governors are employed in the case of a direct-acting engine to effect, in com-
bination with the parts described, an automatic cut-off, such governors are limited
to the type which can at present be employed in the case of direct-acting engines,

page_text: such for instance as consist simply of the varying pressure from a water main
which is supplied by the engine.
The
The first part of my invention, constituting the improvements which relate to
steam and other elastic motive-power engines, such as pneumatic, will now bé
readily understood by reference to figure 7 on sheet 5 of the accompanying
drawings, which is a section corresponding to that of figure 1, sheet 1. In this
figure A is the engine cylinder, B B the steam-chest, C a diaphragm dividing the
steam-chest into two. One of such chests with its valves and connections is the
counterpart of the other, and I will describe therefor chiefly the right-hand chest
with its valves and connections. This chest consists of two parts namely:-a part
of larger diameter D and a part of smaller diameter E. G is the steam branch;
which is bifurcated to supply steam to both chests in the manner before described.
The steam port H, cylinder passage I, exhaust port K, cylinder passage L and
exhaust port M correspond to such parts so lettered respectively, figure 1. a b are
pistons fitting respectively within the parts E and D of the chest. j is a ring
corresponding to the ring j figure 1. The pistons a and b and the ring jare formed
together upon one spindle d. The corresponding parts in the left-hand steam-chest
to those lettered a betc. in the right-hand steam-chest are lettered a¹ b¹ etc.
engine will start with the pistons and rings in the position in which they are
shewn on the drawing, the steam passing direct from the branch G through the
steam port H to one end of the main cylinder, and the exhaust passing out from
the other end of the main cylinder through the exhaust port K' and outlet M'.
The piston is thus driven one stroke, and just before reaching the end of such
stroke communication is opened between a small port in the side of the main
cylinder at the back of the piston and a small port o¹ in the steam-chest, by which
means the pistons a¹ and 61 are closed, the ring j also covering the port o'.
Momentarily thereafter the corresponding pistons and ring in the right-hand chest
are driven back into the position in which the corresponding pistons and ring in
the left-hand chest are shewn, in a manner immediately to be explained. A small
port in the side of the cylinder at the back of the piston communicates with the
small port q and thus moves back the pistons a and b and the ring j so as to open
the ports H and K to the main cylinder and thus drive back the engine piston
to the other end of its stroke. The space between the outer face of the piston b
and the end of the chest is placed in intermittent communication with the exhaust
port of the other chest in the manner and for the purpose already described with
reference to previous parts of my invention.
The improvements last described are applicable in the case either of direct-
acting or of rotative engines, as will be readily understood, but are intended
specially for application in the case of direct-acting pumping engines.
Although for the sake of greater convenience of illustration I have described the
second and third parts of my invention previously to describing the first part
thereof, it will be seen that, as stated in my provisional specification, such second
part constitutes nearly the same arrangement as that constituting the first part
of my invention, but that there are certain additions to such first part and
modifications therein as described which by themselves and in combination with
such first part constitute the second part of my invention.
It will be seen that either arrangement of engine as described can be employed
as a reversing engine.
Having thus stated the nature of my said invention and particularly described
and ascertained the manner of performing the same, I declare that I do not limit
myself to the exact details described and illustrated as such may be varied
without departing from the nature of my invention, but what I claim as
my invention and desire to secure by the herein-before in-part-recited Letters
Patent, is :-
First In a steam or other elastic-motive-power engine (such as a compressed
air engine) not required to work expansively, the arrangement of piston valves,
rings, ports and passages, constructed and operating substantially as and for the

page_text: purpose herein described and illustrated specially by figure 7 of the accompanying
drawings.
Second-In a motive-power engine actuated by steam or other elastic motor
(such as compressed air), the arrangement of parts constructed and operating to
produce a rapid cut-off of the elastic motor in addition to performing the functions
which are the purpose of the mechanism referred to in the foregoing claim,
substantially as herein described and illustrated specially by figures
inclusive of the accompanying drawings.
to 4
Third-In a motive-power engine, actuated by steam or other elastic motor,
the arrangement of parts constructed and operating so as to regulate and control
(either by hand, or automatically by means of governors) the point at which the
cut-off referred to in my second claim takes place, substantially as herein described
and illustrated specially by figures 5 and 6 (and partially by figures 1 and 2) of
the accompanying drawings.
Fourth-The method of bifurcating the cylinder passages to suit the arrange-
meut of ports within the valve chest substantially as herein described and shewn
by figure 3 of the accompanying drawings.
In witness whereof I the said Thomas Hancock have hereunto set my hand
and seal this twenty fifth day of June in the year of our Lord one
thousand eight hundred and eighty three.
THOMAS HANCOCK. (L.S.)
Witness:-
JOHN THOM,
Clerk to Stephen Watkins, Assoc. M. Inst. C.E.
Office for Patents,
Wolverhampton,