CERTAIN IMPROVEMENTS IN STEAM ENGINES, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO IMPELLING WHEEL CARRIAGES
Year: 1844

page_text: .
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAIAH'
DAVIES, of Birmingham, in the County of Warwick, Engineer, send greeting.
WHEREAS, I did. by petition humbly represent unto Her present most
Excellent Majesty Queen Victoria, that I had invented "CERTAIN IMPROVEMENTS
IN STEAM ENGINES, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO IMPELLING
WHEEL CARRIAGES," and Her said Majesty, being willing to give encouragement
to all arts and inventions which may be for the public good, was graciously
pleased, by Her Royal Letters Patent, under the Great Seal of the *United
Kingdom of Great Britain and Ireland, bearing date at Westminster, the
Twenty-seventh day of April, (One thousand eight hundred and forty-four,) in'
the seventh year of Her reign, for Herself, Her heirs and successors, to give
and grant unto me, the said Isaiah Davies, my executors, administrators, and
assigns, Her especial license, full power, sole privilege and authority, that I
or they, by myself or themselves, or by my or their deputies, "servants, or
agents, or such others as I or they should agree with, and no others, during
the term of fourteen years from the date of the said Letters Patent, should
and lawfully might make, use, exercise, and vend my said Invention within
that part of Her said. Majesty's Dominions called England, Her' Dominion' of
Wales, and Town of Berwick-upon-Tweed, in such manner as to me, my.'
executors, administrators; and assigns, shall seem meet; and as that. I ör they
shall enjoy the whole profit and advantage arising by reason of the said '
Invention during the said term. of fourteen years. And; for that end; Her
said Majesty requires and strictly commands all Her subjects whatsoever.

page_text: within England, Wales, and Berwick-upon-Tweed aforesaid, that they shall
not, neither directly nor indirectly, make, use, or put in practice my said
Invention or any part thereof, nor in anywise counterfeit, imitate, or resemble
the same, nor make any addition thereto or subtraction therefrom, whereby to
pretend himself or themselves to be the Inventor or Inventors thereof. "And
whereas the said Letters Patent contain a proviso obliging me, the said Isaiah
Davies, particularly to describe and ascertain the nature of my said Invention,
and in what manner the same is to be performed, by an instrument in writing
under my hand and seal, and to cause the same to be inrolled in Her Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said Letters Patent, as in and by the same: (reference
being thereunto had) will more fully and at large appear.
NOW KNOW. YE, that in compliance with the said proviso, I, the said
Isaiah Davies, do hereby declare that my said Invention is described and
ascertained in manuer following, and by the aid of the three Sheets of
Drawing hereunto annexed, that is to say :-
.
My said improvements in steam engines relate to that class of steam engines
which are called rotatory steam engines, because the impelling, action of the
steam against, the piston, or, pistons is caused to produce a continuous rotatory
motion of. a. central revolving axis, to which such piston or pistons is, or..are.
"affixed, so as to project, out from the said axis, in order to move round within a
fixed, steam cylinder, or, fixed;steam cylinders, wherein the said central revolving
axis, and piston, or pistons is or are contained. And whereas many, varieties, of-
rotary engines of the class aforesaid have been invented, as well for the purpose
of raising or forcing water in the manner of pumps as for being impelled with,
rotatory motion by steam in the manner of steam engines, it will facilitate the
description of my improvements, to state somewhat more particularly, that the
said improvements. relate to that kind of rotatory engines wherein the afore
said central revolving axis is situated at. and concentrically with the central
line of the. fixed steam cylinder wherein the piston revolves, and that, the
said central axis has a revolving cylinder of smaller diameter mounted upon.
the said axis concentrically with it, and revolving with it, and occupying,
the central part of the interior hollows of the fixed cylinder, which latter is so
much larger than the aforesaid central revolving cylinder as to leave an
amular cylindrical space, or channel vacant between the circumferences of the
said two cylinders; and within that said space or channel the steam is to
operate for impelling the piston, which latter is a leaf projecting out from the
exterior circumference of the central revolving cylinder, being fastened to or
in one piece, with that circumference, and projecting out therefrom-so far as to

page_text: reach to and apply with close contact and steam-tight fitting against the
interior circumference of the fixed cylinder, wherefore the piston extends all
across the aforesaid annular cylindrical channel (wherein the steam is to.
operate), so as not to permit any steam to escape or pass by the piston without
impelling the piston in such manner as will cause it to revolve around in- its
said annular channel. The two flat ends of the central revolving cylinder, and
the two ends of the piston (which conform to those flat ends in the same plane:
therewith), apply with close contact and steam-tight fitting to the two fixed.
flat ends of the fixed cylinder, but so as to leave the central revolving cylinder.
and the piston at liberty to revolve within the interior hollow of the fixed.
cylinder, and between the two fixed flat ends thereof. The central revolving:
axis of the revolving cylinder and piston passes through circular holes, with
stuffing boxes at the centres of the said fixed flat ends, with suitable packings:
in those stuffing boxes for preventing escape of steam around the revolving
axis, but leaving the same at liberty to revolve freely. And the ends of the.
axis, which protrude out through the said stuffing boxes, serve to transmit the,
revolving motion which the piston performs within the fixed cylinder to any
machinery which is intended to be actuated by the engine. And whereas, in:
order that the steam may be enabled to act against the said piston, so as to impel.
it around in the said annular channel, there must be some fixed stop across.
the said channel against which the steam can react. That stop (in engines of
the kind to which my said improvements relate,) is a sliding steam stop, fitted.
somewhat in the manner of a sluice across the said annular channel in a
radial direction with the plane of such stop; tending towards the central line
of the axis of the revolving cylinder and piston in such manner as to stop or
prevent any circulation of steam around in the said channel, whenever the
said steam stop is-slided inwards (in the manner of a sluice) so far towards
the central line as to pass all across the said channel, and so as that the steam
stop will touch the circumference of the revolving cylinder with close contact
and steam-tight fitting, of the innermost edge of the steam stop against the
said circumference; and when it is in that position, the steam stop is then at
its resting place; also whilst it is in that said position the two ends of, the said
steam stop apply with close contact and steam-tight fitting against the
aforesaid two fixed flat ends of the fixed cylinder; wherefore the steam stop,
as already mentioned, will not allow any steam to pass by it when it is at its
said resting place; but when (in the course of its revolving motion around-in-
the said channel) the piston approaches: near to the said steam stop, then the
same is suddenly slided outwards from its said resting place with a motion in
the direction of its own plane, or radially away from the centre line of the

page_text: axis, so as to withdraw the steam stop wholly from across the channel, -and
keeping it withdrawn during a sufficient interval- of time for permitting the
piston to pass by the place which the stop had previously occupied as its :
resting place across the channel. And as soon as ever the piston has so passed
by, then the stop is suddenly returned or slided-inwards: again towards the- 5
central line of the axis, so as to resume its resting place across the channel.
behind the piston; in order that it may serve again as the steam stop which is
to receive the reaction of the steam, and by the action of which steam it is:
that the piston is to be impelled. The said steam is supplied (as usual in all
steam engines) from a steam boiler, and is admitted into the said annular:1
cylindrical channel (wherein the piston revolves) by the opening of an entrance
steam passage at a part of that channel which is close to the steam stop, and:
at that side thereof from which the piston is receding (or is intended.to
recede), the said steam passage not being opened until after the piston has
passed by the steam stop, nor until the moment when that stop has just been.
slided inwards and completely replaced across the channel at its resting place:
therein, in manner already stated. At that moment. the steam passage.is
opened, and the supply of steam from the boiler is thereby begun to be
admitted into the space in the annular channel which is behind the piston, or
between the hindinost side of the piston and the steam stop. Also, at the
same moment aforesaid, an eduction passage is opened for permitting the
escape of the waste steam which, previous to the removal of the steam stop,
had already performed its intended duty of impelling the piston,. the said:
eduction passage, being at a part of the annular channel which is close to the
steam stop, and at that side thereof towards which the piston is approaching or
is intended to approach in the course of its circulation around in the channel.
And, in consequence of the said opening of the said eduction passage, the:
waste steam aforesaid is permitted to escape freely out of the space in the
annular channel which is before the piston, or between the foremost side of
the piston and the steam stop. And, in consequence of such free escape of
the waste steam out of the space before the piston relieving the foremost side:
of the piston from the pressure of steam, at the same time that a fresh supply.
of steam is admitted from the boiler into the space behind the piston, so as to:
press against its hindmost side, that piston will be urged round in its circular:
channel by the impelling force of the steam, which is so admitted from the.
boiler, and acting behind the piston, the reaction of the force wherewith the:
piston is so impelled being borne by the steam stop. And when the piston
has been impelled nearly all-round its channel, and so far therein as to have
again approached near to the resting place where the steam-stop has been

page_text: standing and still stands across that channel, then the said stop, (which is then
before the piston; is again slided outwards, and withdrawn from its said
resting place across the channel, in order to let the piston pass by that place;
but immediately after the piston has passed by them, the steam stop is slided
inwards, and replaced again in its resting place across the channel, so as to
get behind the piston, in repetition of the action already mentioned. And the
said escape of the waste steam, in consequence of the opening of the eduction
passage, may take place either into the open air (in case of the engine being
worked with high-pressure steam); or into a suitable condenser, in case of a
vacuum being employed; such condenser being provided with a suitable air-
pump, worked by the engine, for keeping that condenser clear of air and
water. And rotatory engines, answering to the general description herein-
before given, have been contrived; and some have been constructed from time
to time, by different persons, with many varieties in the details of the
construction of their parts.
But having now explained what is the kind of rotatory engine to which my
improvements relate, I will proceed (with the aid of the Drawings hereunto
'annexed) to describe an engine constructed according to, and containing, my said
improvements; and I will afterwards, at the conclusion of this Specification, set
forth the particulars of the new improvements constituting the new Invention, for
which Figure 1, Sheet. I., is a horizontal plan and section of the whole engine,
or rather pair of engines, for two similar engines are combined together, the
revolving cylinders and pistons of the two engines being both fastened-on
the same central axis. A, A, which is prolonged throughout both engines, in
order that a continual rotatory action may be communicated to that axis A, A,
for turning the same round, together with any machinery which is to..be
actuated by the pair of combined engines, and which machinery is connected
with either or both of the ends of the-axis. A, A, where those ends come out
through the stuffing. boxes a,.a, at the ends c, c, of the fixed cylinders B, B.
Rotatory engines of the kind herein-before described (in general terms) cannot
operate with their intended rotatory force during the time whilst the revolving
piston is passing by the resting place which the steam stop usually occupies
across the annular channel wherein the piston revolves, but from the time when
the steam stop is began to be withdrawn from its resting place across the channel,
and during all-the interval until the time when the said steam stop is restored
to its said resting place, in manner herein-before described, the said. interval
is an interval of cessation of the impelling action; and the motion of the
piston, during such interval of cessation, can only be kept up by means of
a heavy revolving. fly wheel;, which. must be applied to. or connected with

page_text: the revolving axis of the piston. But, according to my improvements, two
engines being combined. together. with the revolving pistons of both fastened on
the same revolving axis (but projecting out therefrom at opposite sides of the
centre of that axis), one of those pistons will be receiving the full impelling
action of the steam, in mannner herein-before..explained, whilst the other
piston is going through its interval of cessation of impelling action; and
thereby, between the two revolving pistons, a continual rotatory impelling
action is kept up and transmitted by the axis A, A, to the machinery that
is to be worked by the engine. The two engines, which are so combined,
are precisely alike in their construction and mode of operation. The central
axis A, A, extends through the central lines of both the fixed cylinders B, B,
which are disposed one at the end of the other, the interior capacities of the
two cylinders being separated one from the other by. a flat circular middle
plate b, which forms a partition, and serves as a fixed flat end to 'both
cylinders. The axis A, A, passes through a circular hole at the centre of the
middle plate b, fitting truly into that hole. The margin around the circum-
ference of the middle plate 6 is interposed between the end flanges of the
two cylinders B, B; and screw bolts (which pass through both those flanges
and through the middle plate) fasten all three firmly. together, so that the
two cylinders 'become securely united, one at the end of the other, in the
same line but with the partition 6 making a separation between them; each
cylinder B has also an end cover c, fastened on by screw bolts, through the
other end flange of the cylinder. At the centres of those two end covers c, c,
are-the-two stuffing-boxes-a,-a,-for-the-two ends of the axis.A, A,-to-pass-
through. The middle plate 6, and the end covers c, c, enter a little way into
the interiors of the cylinders at each end of each cylinder, in order that the parts
may be certain to fit together truly concentric. The two fixed cylinders B, B,
are both supported upon one foundation plate X, X, to which they are both
firmly bolted down, as is shewn in the Drawings. The two engines which are
thus combined together being alike, the following part of the description will
be confined to one of them, but is to be understood as applying equally to
both of them. In the horizontal plan Figure 1, one of the cylinders is
represented in section, but the outside of the other cylinder is represented.
Figure 2, Sheet II., is an end elevation; and Figure 3, Sheet II., an end
section. The same letters of reference are used to denote the same parts in
all the several Figures. On the axis A, A, a small revolving cylinder D is
fastened, with the piston E projecting-out from one part of the circumference
thereof, the piston E reaching outward from the cylinder D across the channel
to the interior circumference of the large fixed cylinder B and the outer edge

page_text: of the piston, making close contact and steam-tight fitting with that circum+
ference by means of a metallic packing piece e, which is fitted truly (but freely)
into a groove formed in the piston E, (which piston Ę is the same piece of
metal with the small revolving cylinder D), and a blade spring of steel is
applied at the bottom of the groove; beneath the said packing piece e, so as to
force the same continually outwards in its said groove in the piston E towards
the interior circumference of the fixed cylinder B. The said blade spring is
lodged in a cavity, suitably formed for its reception, at the bottom of the groove;
with the two ends of the blade spring applying to and bearing behind the two
ends of the metallic packing piece e and the middle part of the blade spring
bearing against the bottom of the cavity wherein the blade spring is lodged.
The said groove and metallic packing piece e, are disposed somewhat obliquely,
to the central line of the axis A, A, as is apparent in Figure I., in order that
one end of the length of the said piece e may come to the place of the steam'
stop F before the other end arrives at that place, and thereby the passage.
of the revolving piston E, by that place is facilitated. The flat ends of the
small revolving cylinder D,,and of the piston Ę; and its metallic packing piece a
apply with close contact and steam-tight fitting against the two flat ends of
the interior of the large fixed cylinder B; that is to say, against the flat
surface of the partition b, (between the two cylinders) and against the interior.
flat surface C. of the end cover c, and which last-mentioned flat surface is
capable of slight adjustment by means of three setting screws, herein-after
described, for advancing the said flat surface C so much nearer towards the
flat end of the revolving cylinder D, and piston E, as is requisite for keeping
up the aforesaid close contact as the surfaces wear away by use. The fixed
cylinder B has a hollow steam chamber G at one side of it, and formed in the
same piece of metal with the cylinder B, and in that chamber G the sliding steam,
stop F is lodged. The flat surfaces of that stop being two horizontal planes,
which being supposed to be extended towards the axis A, A,, or the horizontal.
central line of that axis, one of those planes: would be above, and the other
would be below, the said central line, which latter would be exactly between
the said two horizontal planes. The steam stop F is truly, but freely, fitted!
into an opening cut through the thickness of the metal of the circumference of
the fixed cylinder B, that opening leading from the steam chamber. G. into: the
interior of the fixed.cylinder B; but the said opening is filled up by the steam
stop F, and which lies in the opening so as to permit of the steam stop-F sliding
in the direction of. its own horizontal plane towards the,axis A, A, until the
end f, of the steam stop F.,, comes in close contact with the circumference: of
the revolving cylinder D, as shewn. in the Figure 3, when. the steam stop F.

page_text: is at its resting place, in order that the steam stop F may, by so sliding, pass
(in the manner of a horizontal sliding sluice) all across the width of the
annular cylindrical channel H, I, which is left between the exterior circum-
ference of the revolving cylinder D; and the interior circumference of the
fixed cylinder B, for the piston E to revolve round in, and for the reception
of the steam by action whereof the piston is to be impelled, and caused to
revolve around in the said annular channel H, I. The steam stop F (as its
name imprōrts) is for stopping the passage of any steam from circulating
around in that annular channel H, I, whenever the steam stop F is slided
across that channel and is at its resting place, as appears in Figure 3. But,
nevertheless, the steam stop F permits of the revolving piston E circulating
quite around in the said annular channel, because by its said horizontal
sliding motion, like that of a sluice as aforesaid, the steam stop F is withdrawn
back from across the channel H, I, as soon as the piston E gets round in the
channel near to the place of the steam stop therein. The steam stop F, when
so withdrawn, lies partly within the steam chamber G, and the rest of the
steam I stop F, within the aforesaid opening that is cut through the thickness
of the metal of the cylinder B, so that as to the end f of the steam stop F,
(which end was in contact with the exterior circumference of the revolving
cylinder D when the steam stop F was at its resting place,) the said end f
will conform with the interior circumference of the fixed cylinder B when the
steam stop F is wholly withdrawn; and when that is the case the piston E
can pass by the end of the steam stop F, as is represented in Figure 10,
Sheet III.; but as soon as the piston E has so passed by the end of the
steam stop F, then the said steam stop begins to be slided forward again with
its horizontal sliding (or sluice-like) motion, so as to pass across the annular
channel H, I, in order to resume its resting position therein. The end of
the steam stop F is a moveable metallic packing piece f, which is fitted into a
groove cut out, in the thickness of the steam stóp F; and the piece, has
liberty of a small extent of motion therein with a spring lodged at the bottom
of the said groove behind the piece f, in a somewhat similar manner to the
blade spring which, as herein-béfore mentioned, is lodged behind the metallic
packing piece e of the piston E. The said spring, behind the piece f, urges
the edge of the said piece ftowards the exterior circumference of the revolving
cylinder D, so as to ensure a close contact with that circumference which is
formed truly concentric with the centre line of the axis A, A. And, note,
a groove may be formed in the flat surface of the partition b, for the reception
of the edge of the sliding steam' stop F; also another such groove may be
formed in the flat surface C, of the end cover c, for the reception of the other

page_text: edge of the sliding steam stop F. By such groove or grooves the edges of the
steam stop F will be more securely retained for keeping it in its intended
horizontal position, and its sliding motion will be facilitated. The requisite
sliding motion of the steam stop F is communicated to it by a pair of
revolving camns K, k, which are fastened side by side on the axis A, A,
see Figures 1 and 2, so as to revolve therewith, and they operate upon
curved pieces l, m, and n, o, which are fastened into a box L-surrounding
the two camns K, k, and including them within it.. The box L is mounted
at the middle part of a rod, g, h, which is moved endways, backwards and
forwards at proper times, by alternate action of the revolving camns K and k,
upon the curved pieces l, m, and n, o, within the box L. The end g of the
rod g, h, is sustained by a link, which link is supported by a standard bolted
to the foundation plate X, and the other end h, is jointed to the upper end of
a lever M, which projects upwards from a horizontal axis N, whereon a forked
lever O is fixed, with two prongs, so as to stand upwards from the axis N in a
parallel direction to the lever M. The upper ends of the two prongs of the
lever O are connected by links with the cross head of a horizontal sliding
rod p, (see Figure 1) which passes through a stuffing box into the steam
chamber G; and' is there connected by means of a tee-head with the 'sliding
steam stop F, which is within that chamber. The box L, and the rod g, h, is
moved endways backwards and forwards'; consequently when alternately by
action of first one camm K, upon the curved pieces l, m, in the box L, and then
by the action of the other camn k upon the other curved piece n, o, in the same
box L, such backward and forward motion of the box L will be duly transmitted
to the steam stop F, so as to move it outwards, and after a short pause, inwards
again with a sudden motion each way; and then holding it firmly motionless
inwards at its resting position, as is required, for portions of the exterior edges
of the camuis K and k, are formed with arches of circles concentric with the axis
A, A, the arch of the camm K being a semicircle, but that of the camm k only
small arch; and when; in the course of the revolution of the said camuis, -their
concentric arches come to act against the prominences of the middle parts of
curved pieces l, m, and n, o, then these concentric arches hold the box L
motionless; that is to say, when the sliding steam stop F has continued at its
resting position, as in Figure 3; until the revolving piston E, in the course of
its circulation around in the annular channel H, I, is got round near to the
place of the steam stop F, as in Figure 8, Sheet III., then the hindmost corner
of the semicircular arch of the camm K quits its previous contact with the pro-
minence of the curved piece 7, m, and at the same instant the foremost. corner
of the small concentric arch of the other caum k,comes in contact with the

page_text: other curved. piece n, o, at n, and by acting thereon, suddenly moves the same
laterally, together with the box L and the rod g, h, and by means of the levers
M and O, and rod p, the said motion is transmitted to the steam stop F, so
as to move the same away from the axis A, A, and withdraw the same from
across the channel H, I, with a motion just so fast as to keep its end f
out of the way of the revolving piston E, as the same continues moving
onwards in the said channel; and the extent of that withdrawing motion is just
so far as is requisite for removing the steam stop F wholly from across the
channel H, I, until its end ƒ comes into exact conformity with the interior
circumference-of-the-cylinder B, and that conformity takes place by the time
that the revolving piston E has got round to the place of the steam stop, (see
Figure 10, Sheet III.; and then the small arch of the camm K, k, holds the
steam stop F. motionless during a short time, viz, while that small arch
continues in contact with the prominence of the curved piece n, o, that is, until
the piston E has just passed by the end f of the steam stop F, and by that
time the foremost corner, of the semicircular arch of the camm K begins to
act. against the .curved piece l, m, in the box L.at l, the hindmost corner of the
small. arch of the camm k having at the same moment quitted its previous
contact with the prominence of the curved piece n, o, and by that action of K
against 7, the box L, with the rod g, h, is begun to be moved forwards again
towards the axis A, in preparation for replacing. the steam stop F across the
channel H, I, and which is done with as great-rapidity of the advancing motion
of the steam-stop F as can be given thereto, consistently with keeping the end.
f of the steam stop F out of the way of the revolving piston E, as the same
continues moving onwards in the said channel; and the extent of the said
advancing motion is just so. far as is requisite for restoring the steam stop F to
its resting place across the channel H, I, with the end f of the steam stop in
close contact with the exterior circumference of the revolving cylinder D (as
in Figure 3). And by the time that the steam stop F has been so replaced in
its said resting position, then the semicircular arch of the camm K comes
again into operation against the prominence of the curved piece l, m, so as to
retain the box L, rod g, h, and levers M, O, and consequently the steam stop F,
motionless in the said resting position; and the said semicircular arch con-
tinues so to retain the said parts until the revolving piston Ẹ has got round again
near to the place of the steam stop F,, and requires the same to be again with-
drawn out of the way of the piston,, which is done by a repetition of the action
already: explained. And note, respecting the two engines which are combined
together as: before mentioned, the revolving piston E of one of these engines
projects. out from their common axis A, A, at the opposite side of the centre of

page_text: ⚫ the said axis to that side thereof from which the other revolving piston projects
out, and consequently those pistons do not come to the places of their respective
steam stops F at the same time, but alternately by turns; and the revolving
camms K, k, of each engine (see Figure 1), are fastened on the axis A, A,
5 suitably for moving the steam stop F of each engine, in the manner already
described, at the proper times, when the revolving piston of each engine.re-
spectively has got round near to the place of its own steam stop. The axis A, A,
may have a fly-wheel fastened upon it, as is shewn in Figure 1, in order to
render the revolving motion of the axis A, A, perfectly uniform if required;
but such fly-wheel is not indispensably requisite with two engines combined
together, as herein-before described, because one or other of them is always
exerting its full impelling power. And as to the admission of the supply of
steam from the boiler into the annular channel H, I, for the purpose, of
impelling the revolving piston E around in that channel, and also as to the
discharging of the waste steam from the said. channel H, I, after it has per-
formed its duty of impelling the piston therein, in order that such waste steam
may not remain in the said channel before the piston, so as to be an impediment
to the motion thereof in the said channel, such admission and discharge are
caused to take place in due order, by means of two curved passages which are
formed within the substance of, or through the sliding steam stop F, one for a
steam passage, and the other for an eduction passage in such manner as that
the said passages are opened and closed by the motion. herein-before described
of the steam stop F, in a suitable manner for performing the office of a sliding
valve, such as is commonly used in ordinary steam: engines for effecting the
'admission and discharge of steam into and out of the steam cylinder wherein
the piston operates. The steam chamber G is kept supplied by steam which is
conveyed into it from the boiler .through the steam pipe or passage Q and
regulating or throttle valve R in the steam box T, Figure 8. The steam:stop
F is lodged in a cell at the bottom part of the steam chamber G, or rather
beneath that chamber, for there is a partition plate. r, fixed horizontally within
the lower part of the steam chamber G, and the space beneath that plate r..
forms the said cell wherein the steam stop F is lodged; and although the steam
stop is exactly fitted into that cell, so as to fill the same completely, never-
theless the steam stop F is at liberty to slide freely therein, with its motion
endways, inwards, and outwards, as herein-before described. The curved
passages, within the steam stop F, is the steam passage. It turns up at each
end so as to open with orifices at the upper flat surface of the steam stop F,
the places of those orifices in the said surface being such as that whenever the
steam stop Fis at its resting position (as in Figure 3.) with its front or inner.

page_text: end fin close contact with the circumference of the revolving cylinder D, then
the orifice of that end of the steam passages, which is nearest to the inner
end f, will be fully opened, in consequence of being within the interior circum-
ference of the fixed cylinder B; and the other orifice at the further or outer end
of the steam stop F will also be fully opened, in consequence of being beneath a
corresponding orifice of an aperture d, which is cut downwards through the
horizontal partition plate r, and which apperture d permits steam from the
steam chamber G to pass down into the steam passages, within the steam stop
F, and after passing horizontally along all the length of the passages, the
said steam then ascends and issues through the orifice at the inner end f, of
the steam stop F, into the annular channel H, I, at the part H thereof which
is behind the revolving piston E, being the space included between the piston
E and the steam stop F. And whereas the latter, when it is at its resting
position, as in Figure 3, does not permit any steam to pass by it, or downwards
into the part I of the channel; and also whereas the revolving piston E does
not permit steam to pass by it around or forwards in the channel H, I, to the
part I thereof, it follows that the supply of steam from the boiler, which is
thus admitted from the steam chamber G through the steam passage's, into
the part H of the channel, will have a tendency to press the revolving piston E
onwards or forwards, around in the annular channel H, I, in the direction'
shewn by arrows in the several Figures, with the intended revolving motion,
and the steam stop F will sustain the reaction of the pressure which the
steam thus exerts against the piston. But in order that the piston may be
able to move onwards by the said tendency, in manner aforesaid, it is necessary
that any waste steam which may be contained in the part I of the annular
channel H, I, should have free liberty to escape from before the piston, and
such escape takes place through the eduction passage herein-before mentioned,
within the steam stop F, which is a similar passage to the steam passage s, and
disposed side by side therewith in the substance of the steam stop F, (see the
dotted line in Figure 1, Sheet 1,) except that the eduction passage turns down-
wards at each end, and those ends open with orifices in the under flat surface of
the steam stop F, instead of the ends turning upwards with orifices in the upper
surface of the steam stop F, as is the case with the steam passage s. The
steam and eduction passages have no communication one with the other,
although they are situated close side by side in the steam stop F, as appears
in Figure 1 each passage occupying nearly half the extent of the steam stop
F, (measuring that extent horizontally in the direction parallel to the axis A, A).
The steam and eduction passages have their respective orifices in the upper
and under flat surfaces of the steam stop F, sitúated at an equal distance from

page_text: :
the inner end of. the steam stop, as appears, in Figure 1; and therefore
whenever the steain stop F is at is resting position, as in Figure 3, the orifice
of the eduction passage will be fully opened, in consequence of being within
the. interior circumference of the fixed cylinder. B, in the same manner as the
orifice. of the steam passage & is then fully opened; but the, orifice of the
eduction passage.being.in the under flat surface of the steam stop F, the said
orifice and. passage communicates with the part I of the annular channel,
whilst the orifice of the steam passage s,; being in the upper flat surface of the
steam stop F, the latter orifice and..passage, communicates (as already men-
tioned) with the part H of the annular channel. S, Figure 3, is the eduction
pipe or passage, which is provided for conveying the waste steam away from
the engine, either to make it escape up the chimpey or into the open air (if
high pressure), or else to be condensed in a condenser (if a vacuum is to be
employed). The eduction pipe or passage S turns up beneath the sliding
steam stop F, and opens with an orifice t in the upper flat surface at the
bottom of the cell wherein the steam stop Fis lodged, which orificet corresponds
to the orifice of the eduction passage at the outer end (and at the under.flat
surface) of the steam stop F, whenever that steam stop is at its resting position,
as in Figure 3. And there will then be à full passage always kept. open for the
escape of the waste steam from the part I, of the annular passage H, I, that is to
say, an entrance upwards for such steam from I into the orifice of the eduction
passage, at that end thereof which is nearest to the inner end of the
steam. stop F; and after. passing horizontally through all the length of that
eduction passage, then passing down again through the other orifice of the
same eduction passage which is near the outer end of the steam stop, and
thence downward through the corresponding orifice t at the bottom of the cell
wherein the steam stop F is lodged, into the eduction pipe or passage S, by
which the waste steam is carried away. And in consequence of the sliding
motion of the steam stop F, as herein-before explained, the aforesaid orifices of
the steam.and.eduction passages. in the upper and under .flat surfaces thereof
become closed when the steam stop F is withdrawn from its resting position;
in order to let the revolving piston E pass by the place of the steam stop, as is
represented in Figure .10, Sheet III., and no steam is either admitted into or
withdrawn from the channel H, I, whilst the piston is so passing by the said
place. And after the revolving piston-E has passed by the place of the sliding.
steam stop F, and after the same has been slided inwards again so far. toward
the axis A, A, as that the moveable metallic packing piece f, at the inner
end of the steam stop F, first comes. closely in contact with the circumference
of the revolving cylinder D; (as is shewn in Figure 4, Sheet III.,) then at that

page_text: moment the. orifices of the. eduction and steam passages in the under and
upper flat surfaces of the steam stop. Fare just. beginning to open in conse-
quence of those orifices then beginning to emerge from the cell wherein the
sliding steam stop F. is lodged, and by so emerging are beginning to get within
the interior circumference of the fixed cylinder B; and as the steam stop F
continues its sliding motion further inwards towards the axis A, so as to get to
its-resting position, as shewn in Figures 3, 4, 6, and 8, then the said orifices
become fully-opened and give complete exit and entrance passages for the steam
in the manner already explained. And note, it has been already mentioned
that the spring behind the moveable metallic packing piece f, at the inner
end of the sliding steam stop F, will allow that piece f to move a little way.
within the groove in the end of the steam stop F, wherein the said piece f is
fitted: Wherefore, although the inner end of that piece f first makes its close
contact with the exterior circumference of the revolving cylinder D, just before
the orifices of the steam and.eduction passages begin to be opened, (and con-
siderably. before the steam stop has reached its resting position,) nevertheless
the yielding of the said spring, and the consequent motion of the piece within
its said groove, will allow of the steam stop F being moved as much further
inwards towards the axis A (after the said first close contact has taken place)
as is requisite for fully opening the orifices of the eduction and steam passages
within the interior circumference of the fixed cylinder E, and thereby commu-
nicating freely with the parts. I and H respectively of the channel H, I. And
in consequence of the piece f making its said first close contact with the
exterior circumference of the working cylinder D, before the orifices of the
steam and eduction passages are begun to be opened, any waste steam which
may be remaining in the annular channel H, I, will have a portion of such
steam retained in the space behind the revolving piston E; that is, the space
left between. the hindmost.side of the piston E, and the upper side of the steam
stop F, at the moment when the piece f has just made its first close contact
aforesaid. And as to the portion of waste steam that is so retained, the same
will be so much steam provided towards the filling up of the said space with
the fresh steam which is about. to be supplied from the boiler, as soon as the
orifice at the innermost end of the steam passage s, in the steam stop F, is
opened,. in consequence of the further motion of the steam stop carrying the
same to its resting position. And note, respecting the horizontal partition plater,
at the lower part of the steam .chamber G, the under flat surface of which
plate. forms the upper part of the cell wherein the sliding steam stop F is fitted,
and wherein it slides; see Figure 3, the said plate r, although it is fixed
firmly horizontally across the lower part of the steam chamber G, is neverthe-

page_text: less capable of slight adjustment as to its height therein, in order that the cell
beneath the plate r, wherein the sliding steam stop F is fitted; may be truly
adapted to the thickness of the said stop F as the surfaces wear away. For
this purpose the partition plate ŕ is accurately fitted at its edges to the inside
5 of the steam chamber G, and a flange, which turns up from the end of the
partition, plater, applies to and is fastened by horizontal screws against
the inside of the chamber G, nearest to the cylinder B. Also there are vertica-
setting screws a, a, and y, Figures 1, 2, and 3, with their heads outside of the
steam chamber G, and those screws descend through the upper part of it, and
screw at their lower ends into parts of the partition plate r; so as to suspend or
uphold the same within the steam chamber G. But by means of those hori-
zontal screws aforesaid, and the said setting screws x and y, the partition plater.
can be let down as much lower within the chamber G as is requisite for the
purpose of the slight adjustment aforesaid. And there may be other vertical
setting screws, similar to a, a, and y, except as to being adapted for pressing
the partition plater downwards within the steam chamber G, in opposition to
the screws, x, and y, which act to pull that plater upwards; and by means
of the said two sorts of counteracting setting screws the partition plater can. be.
made quite fast, and exactly in its required place at the lower part of the steam
chamber G. And note, it has been already mentioned respecting the flat.
surface C of the end cover c, (which surface C must make a close contact and
steam-tight fitting with the flat end of the revolving cylinder D and piston E,).
that the said flat surface C of the end cover c is capable of slight adjustment
by means of three setting screws z, Figure 1. For that purpose the said flat
surface C, which is capable of adjustment, is a flat circular plate C, of the same.
size as the interior of the fixed cylinder B; which plate C is quite distinct from
the end cover c, but is kept firmly in place by being entered into the end of the
fixed cylinder B. The three setting screws z, Figure 1, are screwed through
suitable places in the end cover 'c, so as to press with their inner ends. behind
the said circular plate C, in order to advance the same inwards into the end of
the fixed cylinder B, and towards the flat end of the revolving cylinder D and
piston E. And, there may be three other counteracting setting screws provided.
for pulling the said plate outwards in opposition to the first-mentioned setting.
screws z, so as, by the contrary action of the two sorts of screws, to hold the said
circular plate C quite fast, and exactly in its required place. And note, the
three first-mentioned setting screws z, which, are to advance the said circular.
plate C inwards; may be made hollow like tubes, to receive. the other. lust-
nentioned pulling screws within them, the heads of the inner screws. projecting
beyond the heads of the hollow screws, as is clearly seen in Figure 1.And in like

page_text: manner hollow setting, screws, having other counteracting setting screws within
them, may be used at x, x, and y, for adjusting and fixing the partition plate r.
The steam pipe or passage Q, and the eduction pipe or passage S, pass side by
side beneath the engine,.as appears in Figure 8, or they may pass in any other
convenient manner so as to arrive at and join to the steam chamber G, in the E
manner already explained, both. the. pipes, or passages Q and S coming from a
steam box T, containing, the regulating or throttle valve. R, by which the
rapidity of the supply of steam from the boiler to the engine is to be regulated,.
and consequently the rapidity of the motion of the engine. The valve R is .a.
flat sliding valve, which is fitted with close contact.and steam-tight fitting,,
to slide on the flat bottom of the box T, into the interior capacity of which box.
steam from the boiler is constantly introduced through the steam pipe W, which
comes from the boiler. The valve R can be slided at the bottom of the box T.
when required, by means of.a.lever handle Z, which is connected with the valve
by a rod passing horizontally through a stuffing box-in one side of the box. T..
When the lever handle. Z is inclined from a vertical position towards the
engine, as appears by dotted. lines in Figure 3,, then the valve R uncovers
and opens either wholly. or partially the orifice i, wherewith the steam pipe or
passage: opens upwards in the flat surface of the bottom of the box T, and
steam from the boiler, which is always coming through the steam pipe W into
the box.T; is, admitted therefrom into the steam pipe or passage Q through
the said orifice i,- or so much thereof as is opened. And according as the.
lever Z is more or less inclined-from the vertical, so more or less of, the said
orifice of the steam pipe or passage Q is uncovered and opened, as aforesaid,
and in that manner the sliding valve R answers the purpose of a throttle valve.
Aud at the same time the orifice j, wherewith the eduction pipe or passage S
opens upwards in the flat surface of the bottom of the box T, is completely
covered over by the hollow within the sliding valve R, so as that the whole of the
said orifice j.is left open beneath the said hollow, which hollow also covers over
and connects the said orifice with another orifice in the flat surface at the
bottom of the box T. The latter being the orifice of the eduction or waste
steam pipe V, which leads the waste steam away from the engine, either for
discharging that steam into the open air, or else for discharging the same
through a vertical jet pipe (or pipes) up the chimney of the furnace. for
the boiler, in order to augment the rapidity of the draft or current. of air
through the fire; or else for conveying.the waste steam away to a. suitable
condenser, wherein it will be cooled and-condensed, in order to obtain a vacuum.
And note, the box T, and the valve R. therein, serves both the engines of the
two, which are combined together, as is shewn in Figure 1.;, for the steam-pipe

page_text: or passage Q, and the eduction pipe or passage S, each of them separate into two
branches at the part where they appear to rise up, in Figure 8, beneath the
steam chamber G; and one such branch of each pipe or passage goes up beneath
and joins to the steam chamber G of one engine, in the manner already
explained; and the other such branch goes up beneath and joins in like
manner to the corresponding steam chamber of the other engine, wherefore
the constant supply of steam which is furnished by the boiler is conveyed by
the steam pipe W into the interior of the box T, above the sliding valve R.
And that valve, according at it is placed by its lever Z, admits more or less of
the steam to pass down from the box T through the orifice i of the steam pipe
or passage Q, (or through so much of that orifice i as may at the time be
opened,) and after passing horizontally along the said pipe or passage' Q, and
then passing upwards and through the two branches aforesaid into the steam
chambers G of both engines, to fill the space therein above the horizontal parti-
tion plate r, and from thence the steam flows down through the aperture d, in
that plater, and turns into the horizontal steam passages in the sliding' steam
stop F, (whenever that stop is at its resting position, and after passing hori-
zontally along that passages, then the steam' issues upwards through the orifice.
at the inner end f of the upper flat surface of the steam stop F, into the part H
of the annular channel H, I, wherein the revolving piston E is to be impelled
round by the action of the steam so introduced behind the said piston; the
reaction of that steam being sustained by the steam stop F. At the same time
the waste steam is allowed to escape freely from before the piston; that is to say,'
from the part I of the said annular channel, by entering upwards through the
orifice of the eduction passage at the inner end f of the under flat surface of
the steam stop F, and after passing horizontally along that eduction passage,
then turning down through the orifice at the other end of it, and descending
through the corresponding orifice t at the bottom of the cell, wherein the steam
stop F is lodged, into the two branches of the eduction pipe or passage, which'
join into one pipe or passage S. In descending, and after passing horizontally
along the said eduction pipe or passage S, then turning upward beneath the box T,
and-ascending through the orifice j at the flat bottom of that box into the hollow!
beneath the valve R, and then from that hollow passing downwards again through!
the other orifice at the bottom of that box, which orifice leads into the eduction
pipe V, by which the steam is carried completely away from the engine in
the manner already mentioned. And note, respecting the eduction pipe or
passage S, at the .descending part thereof beneath the steam chambers G'of
each engine, and at the place where the two branches which communicate
with the two engines form their junction into one eduction pipe or passage S,

page_text: the said junction should be made by the two branches of the eduction pipe
or passage from each engine approaching gradually side by side, one branch
towards the other, as they descend from beneath the steam chambers G of
each engine respectively, but with only a small angle of inclination of one of
those branches towards the other; and also a thin partition should be con-
tinued between the said two branches internally, for some distance beyond
the place, where the two branches appear to become one pipe or passage, S,
externally. Such a mode of joining the two branches of the eduction pipes
or passages of the two engines into one common eduction pipe or passage S,
will avoid impediment to the free escape of waste steam from one engine when
the other.engine first begins to discharge its accumulated waste steam with a
sudden puff. And whenever the handle Z of the sliding, valve R is moved
in a vertical position, as, appears in Figure 3, then it will slide the valve R
into such a position as that it will wholly close and shut up the orifice of the.
steam pipe or passage Q, at the flat bottom of the box T, and thereby the
influx of steam from the boiler (through the box T) into the engine, will be
wholly prevented, and consequently the working of the engine will be stopped.
That position is represented in Figure 3. But note, at the same time that
the.. sliding valve R first begins to close the orifice i of the steam pipe or
passage Q, in the manner of a stop valve as aforesaid, it nevertheless leaves
the orifice of the eduction pipe. or passage S, open to a considerable extent;
because when the sliding valve R is used in the manner of a throttle valve,
to close more or less of the orifice i of the steam pipe or passage Q, in order
to impede or regulate the entrance of steam from the box T into that
orifice i, it is not intended that the valve R should at same time impede the
free passage and escape, of the waste steam from the orifice i of the eduction
pipe or passage S, to the eduction or waste steam pipe V, and it is not until
the steam orifice.i.is almost closed that the eduction orifice begins to be
closed..And.in, addition to the use of the sliding valve R, in the manner of
a throttle valve and of a stop valve as. aforesaid, the same valve R being
moved by inclining its lever handle Z, in a contrary direction to that repre-
sented by the dotted lines, in Figure 3, or. away from the engine, and then
that valve will cause the engines to turn round backwards, that is, to revolve
in a contrary, direction to that which has been herein-before. described, and
which is represented by the arrows in the. Drawings,, because the sliding
valve R, when so moved, will reverse the character of the two pipes or pas
sages Q and S, the pipe or passage S becoming the steam pipe or passage, and
the pipe or passage Q becoming the,eduction pipe. or passage. And the same
of the passages in the sliding steam stop F, in which case it is obvious that

page_text: the action herein-before described of the steam will be, reversed, for the steam
from the boiler will be admitted into the part I of the annular channel H, I,
and the waste steam will be allowed to escape from the part H of the same
channel; the passages, in the steam stop F, haying become the eduction
passage, and the interior capacity of the steam chamber G, will serve for the
escape of the waste steam; instead of being filled with steam from the boiler.
And the same may be said of both the engines, which are combined, wherefore
(in the manner herein-before described) the whole action of the two combined
engines is regulated by the lever handle Z. When that is in a vertical
position (as in Figure 3), then both the engines will be stopped; but when
the same lever handle Z'is inclined, from the vertical, then the engines will
be started into motion. If the lever handle Z is inclined over towards the
engines, as shewn by the dotted lines, Figure 3, then their revolving pistons E
will be caused to turn round forwards in the direction shewn by the arrows;
but if the lever handle Z is inclined away from the engines, then their revolv-.
ing pistons will be caused to turn round backwards, or contrary to the arrows,
the pistons in either case revolving quicker as the lever handle Z is more
inclined, and slower as it is less inclined. And the camms K and k, and the
curved pieces l, m, and n, o, within the box L, are all made symetrical; as is
apparent in Figure 2, so that those parts will operate in the same manner for
moving the sliding steam stop F at the proper times, in manner herein-before
described, as well for going backwards as for going forwards; the curve on
being operated upon by the camm K, in going backwards in the same manner
as that camm operated upon the curve in going forwards, and the curve o
being operated upon by the camm K in going backwards in the same manner
as that camm operated upon the curve n going forwards.
Figures 12, Sheet III., shews a substitute for the camms K and k, and
box L, but producing precisely the same result; as to the moving of the sliding
steam stop I suddenly, and at the proper times, first outwards and then inwards
again; likewise as to the holding of the said steam stop L motionless, all the time
whilst it is in its resting position, as in Figure 3, and also for a short time when
it is quite withdrawn from across the annular channel H, I, and the revolving
piston E passing by the place of the steam stop F. In Figure 12, A is the
main axis, and K is a lever arm fixed thereon, and having two small steel
rollers at the end of K, one roller at each side thereof, so that the two rollers
appear only as one in Figure 12. The interior of the box Ĺ'is a circular
arch for about a semicircle; and when the sliding steam stop F is at its resting
position, as in Figure 3, then the semicircular interior of the box L is consentric
with the axis A, in which case, and one of the steel rollers at the end of the

page_text: arm K is carried about half round within, and in contact with that concentric
semicircular circumference, that the roller gives no motion to the box L, but,
on the contrary, it prevents any motion thereof. The sides of the box L have
oblong holes through them, to fit truly upon the axis-A, but the oblong form
of the holes allows the box L to move as far as required, but no further.. The
remaining portion of the circular interior of the box L, is filled up with a
piece of steel l, m, firmly fastened into the circular interior; and when thé
said steel roller in the course of its revolution (with the arm K,) comes round-to
the part l'or'm, according to the direction of the motion, viz,. in going for-
wards (but min going backwards); then that roller moves the box L laterally
with a sudden 'motion, suitably for withdrawing the sliding steam "stop F;
from its resting position, Figure 3, (or Figures 4, 6, and 8, Sheet III.,) and
for moving the steam stop to the position shewn in Figure 10, which is; when>
the steam stop F is wholly withdrawn from the annular channel H, I, 'in-
order that the revolving piston E may pass by the place of the steam stop F;
and for so long as the sliding steam stop F is required to remain motionless.
After being so withdrawn, the steel roller will be moving against a short.cir-
cular curve, or arch u, which extends from the part to the part m; and the
arch u being at that time consentric with the centre of the axis A, no motion
is given by the roller to the box L, until the time when the revolving piston E
has quite passed by the place of the sliding steam stop F, and the latter is
required to begin its return inwards towards the: axis A. By that time the.
said steel roller will have moved all the length of the said short-circular-
arch Ug and then the other steel roller will begin to act against the part n (or o,
according to the direction of the motion, viz, n, in moving forwards, but o
in moving backwards), and in so acting that other steel roller will move the
box L laterally with a sudden motion, suitably for returning it across the
annular channel H, I, and regaining its resting position; and the time that
position is regained, the said steel roller will begin to travel around in a semi-
circular channel, which is formed between within the interior of the box L, and
the exterior circumference of a smaller semicircle v, which belongs to the parts
and o; and the said semicircular channel being at that time concentric.with
the axis A, (as appears in Figure 12,) no motion will be given to the box-L
by. the motion of the steel roller around in the said semicircular channel, but,
on the contrary, motion thereof will be prevented. And both the steel rollers
may act in concert against the interior of the semicircular arch of the box L;
in fact both the steel rollers may concur. in producing all the action above
described, provided that the filling up piece l; u, m, has a sufficient breadth of
edge for receiving the action of both rollers; and also, provided that there are two

page_text: pieces of steel similar to the part n, v, o, one such piece applied to each side of
the box Li, and consequently at each side of the lever arm K, but having a
clear space between the two pieces of steel for the said arm K to move round
between them. In such case the two rollers will concur; but either roller by
itself. will perform the action above, described, because, it will circulate around
within the curved channel, which is represented in Figure 12 by shadowing.
And it is obvious from the foregoing description, as well. as. from inspection
of Figure 12, that the aforesaid action will take place as well for going back-
wards as for going forwards, the straight parts m ando of the aforesaid
curved channel being operated upon by the steel rollers, in going backwards,
in the same manner as those, rollers operated upon the straight parts land n
in going forwards. And the box L; Figure 2, as well as the box L, Figure 12,
is adapted. to hold oil at the lower: part of; it; for supplying the camms or the
rollers as they revolve within the box: In Figures 2 and; 12, one side of the
box' L is represented as being removed, to shew the interior of the box. The
two sides of the box L; Figure 2, have oblong holes through them for the
axis A to, pass through, in the same manner as, already mentioned in, reference
to Figure 12. And note, when a governor is to be applied to a pair of com-
bined engines of 'the kind herein-before described, for the, purpose of regu-
lating the speed of the motion thereof, then an ordinary throttle valve (of a
suitable: kind for being actuated by a governor,) should be provided, in addi-
tion to the sliding valvo 'R, and its lever handle Z, which will in such case be
only used for starting the engines cither forwards, or backwards, and for
stopping them. And note, when a vacuum is to be, used, an air pump or
pumps will be required; as already mentioned; such air pump or pumps, (as
well as a hot water or feeding pump or pumps) for supplying the boiler) may
be wrought by means of a crank or cranks on the main axis A, A, or by
any other suitable means..
And as to that part of my said improvements which are applicable to impelling
wheel carriages, the same consists in applying a pair of combined rotatory engines,
of the kind herein-before described, to give rotatory motion to the wheels of
carriages either for travelling on common roads or on railways; by intervention
of an endless screw (or of endless screws), which, being turned rapidly round
by the said engines, and acting in the teeth of a suitable cog wheel or wheels
on the axis (or axes) of the wheels of such carriage, will cause the said wheels,
thereof to be turned round, and will consequently cause the carriage to be im-.
pelled along the road or railway,.and that either in a forward or in a backward
lirection, as may be required, accordingly as the lever handle Z may be.
nclined one way or the other, as herein-before described; and the speed of the

page_text: .
motion (either way) will be greater or less as the said handle Z is more or less
inclined either way from the vertical; or, when the said handle is brought to
its vertical position (or nearly so), then the motion will be stopped altogether,
and tooth wheel-work may, if preferred, be interposed between. the main axis
A; A, of such combined pair of engines and the aforesaid endless screw, in order
(by changing the gearings of such wheel-work) to give the engines more power
for impelling the carriage up hills with a heavy load, over bad portions of road,
and inclined planes, than is, required for impelling the same carriage with a
light load, and on good and level portions of the road or railway: see Figurės 13
and 14, Sheet III., Figure 18 being an lateral elevation or section, and
Figure 14 'a transverse section. B, Figure 13, is one of the fixed cylinders of
the pair of compound engines; A, the main axis thereof, which is horizontal;
P, a small spur wheel fitted on the axis A; so as. to turn round therewith, the
teeth of P gearing with those of another spur wheel M on the axis N of the
endless screw I, the spiral threads whereof act in the corresponding teeth of
the worm wheel O, which is fastened on the horizontal axis H of the two
wheels K, K, of the carriage. And note, the axis N may be prolonged
sufficiently for having another such endless screw as L upon it for actuating
another such worm wheel as O, which may be fastened on the horizontal axis
of another pair of wheels of the carriage, so as to impel four wheels thereof if
required. But the said additional endless screw and worm wheel may be
disengaged one from the other in cases when it is only required to impel two
wheels K, K, of the carriage; and p is another spur wheel of a larger size
than P, but applied by the side thereof, both the spur wheels P and p being
fastened side by side on a short hollow axis or socket q, which is fitted upon
the main axis A, so as to be obliged to turn round therewith, but nevertheless
so as to be at liberty to slide endways on the axis A, in order by so sliding to
disengage the teeth of the spur wheel P from those of the wheel M by a
lateral disengagement of those teeth; and the said sliding, being continued
further along the axis A, will bring the teeth of the wheel p, by a lateral
engagement, into gear with those of a smallar spur wheel m, which is fastened
on the axis N of the endless screw L, in order that the said screw, and conse-
quently the wheels K, K, of the carriage may be turned round quicker, for
enabling the engines to impel tlie carriage at a greater speed than will be
done when the wheels P and M are in gear together, as in Figure 13, for
they are adapted for enabling the engines to impel the carriage with more
power when it is required to travel with a heavier load, or over bad portions
of road, and to mount up ascents.
Figure 15 explains how a mould may be constructed for forming the spiral

page_text: threads of the endless screw L, by casting the same of what is termed chilled
cast.iron. The mould itself, being made of cast iron, causes a sudden cooling
of the surface of the melted cast iron, which is poured into such mould, and
will render the metal of the screw, which is so cast, extremely hard at the said
surface, and very hard to some depth into the substance beneath the surface.
The mould, Figure 15, for the spiral threads of the screw, is made in four
segments or pieces e, e; e, e, which are held firmly together, and in close contact
one with.another within an iron hoop or circular frame g, with four pairs of
setting screws, so that the segments can be taken apart. The interior of the
four segments must be cut out to form a. very true and smooth mould for the
spiral threads of the endless screw. A similar mould may be made for
casting the worm wheel O of chilled cast iron, and from the hardness of the
surfaces so obtained there will be but little. wearing away by friction.
Having now described steam engines constructed according to my said im-
provements,, I, the said Isaiah Davies, do hereby declare that what I claim as
the new Invention, whereof the exclusive use is granted to me by the Letters
Patent herein-before recited, consists in the following particulars, viz* :-
passages
Firstly, in the improvement herein-before described in the sliding steain
stop F, with the steam and eduction passages within the same, and so arranged
therein as that the sliding motion of the steam stop will cause the said
to be duly opened and shut, as is required, for admitting steam from the boiler
into the annular channel in which the revolving piston circulates at a part of
that channel which is behind that piston. Also at the same time, for permitting
the waste steam (which has previously performed its office of impelling the
piston) to make its escape freely from that part of the said annular channel
which is before the piston, as herein-before described. Also the application
and operation of: the moveable packing piece f, at the inner end of the steam
stop F herein-before described,
.
Secondly, in the improvement herein-before described of the camms K, and k;
on the main axis A and the curved pieces l, m, and n, o, in the box.L for
giving the requisite motions to. the sliding steam-stop F, viz, outwards, and
then, after a.short pause, inwards again, and then with a long pause whilst the
stoam stop is at its.resting position before moving. outwards again, the said
canims and curved pieces causing the sliding steam stop F to be, held firmly
motionless during the said pauses, as well as operating to move; the same with
promptitude and certainty outwards and inwards at the proper times, without
allowing the sliding stop to move either way neither too soon nor too late, but at
the proper times; neither allowing it to. move too quick nor too slow, but at.
the proper speeds; and neither allowing it to move too far, nor to fall short,

page_text: but giving the proper extent of motion. Also the parts shewn in Figure 12,
and herein-before described, which may be substituted for the camms K,'k, and
curved pieces, m,& n, o, and will produce all the same effects as aforesaid.
Thirdly, in the improvement herein-before described of the manner of applying
a metallic packing piece e to the revolving piston, with an obliquity to the axis
A, and of fitting the sliding steam stop F into its cell with the partition plate r',
adjustable by means of setting screws. Also the mode or manner of applying
the internal flat surface C of the end cover, with adjustment by means of
setting screws.
Fourthly, in the improvement herein-before described of the arrangement of
the steam and eduction pipes or passages Q and S, and the application. of the
sliding box valve R, and which answers all the purposes of a. reversing valve
and a throttle valve and a stop valve. By means of that valve R the direction of
the flow of steam through these pipes or passages can be reversed, and their
character mutually changed instantaneously (the steam becoming the eduction
pipe or passage, and the eduction becoming the steam pipe or passage,) by one
movement of the lever handle Z of the said valve, so as to cause the. revolving
piston to turn round either in a forward or a backward direction, and with a
quick or slow motion either way, or to stand still, as may be required, and as
herein-before fully explained. And also that property herein-before described
of the camms K, k, and curved pieces l, m, and n, o, (and: of the substitute
therefore represented in Figure 12), whereby they will. opcrate properly for
giving the requisite motion to the sliding steam-stop F, as well when the piston
is revolving in a backward as in a forward direction.
Fifthly, in the improvement herein-before described in the manner of com-
bining two such rotatory engines together in a pair, the two large fixed
cylinders B, B, being one at the end of the other, with the main axis A, A,
passing through the contre lines of both, and the two revolving pistons pro-
jecting out from that axis in opposite directions from the central line thereof.
Also the camms K, k, (or the substitutes therefore, represented in Figure 12,)
being fastened on the two ends of the axis A, A, suitably for giving the requi-
site motions to the two sliding steam stops respectively, with the exact mutual
correspondence to the revolving motions of the two pistons respectively; where-
fore the axis A will be caused to revolve with a continuous impelling action,
in consequence of one of the two pistons thereon being always in full action
during the cessation of the action of the other of the two pistons.
And, lastly, that part of the said improvements which are applicable to
impelling wheel carriages consists in the mode herein-before described in
reference to Figures 13, 14, and 15, Sheet III., of applying a pair of combined

page_text: rotatory engines constructed according to and including all or part of the several
improvements already set forth, (under the heads firstly, &c. to fifthly afore-
said,) so as, by intervention of an endless screw (or of endless screws), and a
worm-wheel (or worm-wheels), to communicate rotatory motion to the wheels
of such wheel carriages for impelling the same either in a forward or in a
backward direction, as herein-before described, and with change wheel-work
for enabling such combined engines to impel the carriage in manner aforesaid,
either with extra speed or with extra power, as may be required.
In witness whereof, I, the said Isaiah Davies, have hereunto set my
hand and seal, this Twenty-sixth day of October, One thousand eight
hundred and forty-four.