CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
PILBROW, of Tottenham,in the County of Middlesex, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Victoria, by Her Letters
Patent under the Great Seal of Great Britain,bearing date at Westminster,
the Twenty-third day of May, Onethousand eight hundred and forty-two, in
the fifth year of Her reign, did did, for Herself, Her heirs and successors,
give and grant unto me, the said James Pilbrow, my executors, administrators,
and assigns, Her special licence, full power, sole privilege and authority, that
I, the said James Pilbrow, my executors, administrators, and assigns, or such
others as I, the said James Pilbrow, my executors, administrators, or assigne,
should at any time agree with, and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England and Wales, and the Town of
Berwick-upon-Tweed,and in the Islands of Jersey, Guernsey, Alderney, Sark,
and Man, and also in all the Colonies and Plantations abroad, my Invention
of "CERTAIN IMPROVEMENTS IN STEAM ENGINES," to have, hold, exercise, and
enjoy the said licence, powers, privileges, and advantages therein-before
granted unto me, the said James Pilbrow, my executors, administrators, and
assigns, for the term of fourteen years from the date of the said Letters
Patent: And whereas in the said Letters Patent is contained a proviso that I,
the said James Pilbrow, should particularly 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 cause the same to be inrolled
in Her said Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters Patent,
as in and by the same,reference being thereunto had, will more fully appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
James Pilbrow,do hereby declare that my said Inventions of "Certain Improve-
ments in Steam Engines" consist in a new discovery of the properties of
"steam," by which I have ascertained the proper effect or force due to its
expansive velocity; namely, that both the whole available power and extreme
duty from expansion may be obtained from the simple expansive velocity of
steam when applied in the peculiar manner herein-after described, as well in
locomotive as in other high pressure and condensing engines, on my plan; also
in the engine and apparatus by which such discovery is made available for
propulsion and general purposes, and in the laws or rules by which the best
velocities of my engine are ascertained to give the maximum effect, which
improvements, combined from a "steam engine" characterized by me, to
distinguish its principle from that of all others, as "the injet reaction rotatory
engine;" also in two methods of connecting the same with the machinery to
be moved thereby, one of which I call "the roller" and wheel connection," and
the other, which is a modification of it, "the bevilled groove and spherical
tongue connection," to be used where more than ordinary adhesion or contact
is required between the moving parts.
Wishing publicly to record the origin of my discovery, I shall depart
somewhat from the usual form of Specification, believing that the results
of, my experiments will create a great alteration in the application of
steam, and that my engine will entirely supersede those now in use. The
properties of steam have hitherto been considered of that peculiar nature
as to render it impossible to obtain its full power and extreme duty from
expansion, except by using it according to the present system, that is, by
letting it into a hot or close cylinder on a piston, and stopping its further
entrance by cutting it off to allow it to expand. Feeling, however, a strong
conviction that the whole power was to be obtained by some more simple
means than the present costly, complicated, and ponderous machine, and that
a power so easily raised need not be so laboriously applied, I undertook along
series of experiments to discover how this might might be done. I first com-
menced on the most simple form of engine known to us, that of Hero's, and
ascertained the true causes of its loss of power, and found, after many inventions
to obtain by this simple machine the full power and duty from expansion, that
though I could considerably increase its power by the form of arm shewn in
Figure 1,Drawing C,yet that I could not obtain the whole duty from expansion,
and consequently that an engine on this principle could never be brought to
compete with Mr. Watt's condensing engine. The failure, however, of my
plans to obtain those results disclosed to me the remarkable fact that a current

page_text: of steam in rapid motion, that is issuing from an orifice, loses almost entirely.
that power of lateral expansion which it possesses when cut off and allowed to
expand from a state of comparative rest. When I had confirmed this pheno-
menon by other experiments I was satisfied that steam possessed an impulsive
power of the utmost efficiency entirely different from what had ever been
supposed; for its full expansive force, not being given out laterally, must have
gone somewhere, and as it could only expand in the line of its issue, I became
acquainted with this new and singular property of steam, that it possessed in
its mere velocity alone a propulsive force from its lineal expansibility equal in.
power and duty to the gross effect obtained when cut offand allowed to expand
under the best circumstances. I had next to transmit this new principle of
steam power to machinery, with the least possible loss from friction and other
deductions, by some engine as simple as the principle, and this I supplied as
herein-after described. But I wish first to shew that there exists in nature an
analogy between steam and water as moving powers, when applied by their
simple velocity, that it may be seen how much more in harmony with her.
laws is this discovery than the present system of applying steam. The two
great forces of the universe producing all motion are attraction and repulsion,
and as motion is motion wherever found; whether in steam, water, or a cannon
ball, all motion must bepower, power in proportion to the intensity of motion.
Water,obeying the former law, has been immemorially employed in its natural
state to give motion to machinery merely by its velocity of gravitation. But
no proper advantage has ever been taken of the force of the velocity of steam,
which, governed like all elastic fluids by the latter law, propulsion, issues at a
speed infinitely exceeding that of water, encreasing in velocity in proportion to:
the heat among its particles; yet it has been considered by all writers on the.
steam engine, and on the properties of steam, that it possesses but a feeble
power by emission to turn a wheel in comparison with the quantity expended;
but this error has arisen only because no one has ever thought of ascertaining
the fact by actual experiment of a proper kind, and thus the extreme force of
the velocity of steam has remained undiscovered to the present advanced state
of science. Instead, therefore, of using steam with the same simplicity as
water, the power which steam possesses from velocity has hitherto been
destroyed, the steam being "cut off," as it is called, to allow it to expand from:
a state of comparative rest. Having thus departed from the simplicity of
nature, a complication of beams, levers, connecting rods, pistons, valves,
excentrics, and expansive gear, and vast cylinders of ponderable matter,
became necessary to enable the steam to expand over large areas of surface,
merely to give back to the more simple operations of nature that power which

page_text: is taken from her by complexity; whereas by using it in its more natural and
therefore more simple state, precisely the same advantages may be obtained
by machinery, as cheap, simple, and easy of construction as the water wheel.
But as in all practical sciences there is only one way of obtaining the most
beneficial results, I have found that there is as great a difference in the duty
of steam by the peculiar manner in which it is applied by its velocity, as is
found in effect in the application of water. I shall, therefore, first describe a
few experiments, being some of those which led to my Invention, to shew the
accuracy required. The operation of Barker's mill and of Hero's emission
engine is well known; and though there is no resemblance between their
moving powers, the one acting by gravity, the other by repulsion, there seems to
be a strict analogy between their results proportioned to the power and velocity
of each, so that whether water or steam be used in the following experiments,
the modes of action being similar, that of impulse or transference of motion,the
operation and direction of the arm will be the same; and it will be seen here-
after that I obtain, by my application of the velocity of steam, the same duty
therefrom asisobtained by the best overshot water wheel, namely, a clear avail-
able effect of about two thirds of the whole power of the steam employed, that
is, two thirds of its power and of its extreme duty from expansion, the steam
being expanded in my application of it as low as the atmosphere in high-
pressure engines, and to the vapour point a state of condenser vacuum in
condensing engines, degrees of attenuation which cannot be obtained by the
present system on account of the piston.
Figure II. and III., in Drawing C, represent arms on Hero's principle,
attached in the usual way to a hollow axle (a or b) supplied with steam, and
having orifices at the extremities (c and d). When used in the usual
way, the arms will revolve by unbalanced pressure in the direction of the
arrows (e and f); but when a flat plate is attached immediately before
the orifice (g, Figure 2), the steam will impinge thereon, and being broken
up will change its course as therein represented, and the arm will become
stationary, shewing that the force of impingement equals that of unbalanced
pressure. If, however, a cavity (h, Figure III.) be fixed, instead of the
plate, opposite the orifice, at such an angle that the injet of steam can be
returned by its reaction (i) clear of the arm, without impinging thereon, the
arm will revolve in the contrary direction to that of the previous unbalanced
pressure, and in the direction of the arrow (), with more power than that
with which it revolved the contrary way previous to the cavity (h) being fixed
thereon, proving that the cavity not only received the same amount of
impingement as the flat plate (g, Figure 2,) received (which was shewn to be

page_text: at least equal to the unbalanced pressure); but by this pecumar mjer and
reaction or reissue of the steam, its whole velocity was arrested, and the cavity
thus acquired another power of equal amount sufficient to overcome and carry
round the effect of unbalanced pressure only. But if the steam on its reissue
or reaction from the cavity (h) is permitted to impinge at all against the arm
(d), the arm will then only revolve in the direction of the arrow (j) with
diminished power in proportion to the amount of such impingement; and if all
the steam on its reissue or reaction from the cavity (h) is allowed, by altering
the angle of the cavity to strike fully against the arm (d), the arm will then
remain stationary as when the flat plate (g, Fig. II.) was used.
When I had discovered how this double power was to be obtained by arresting
and transferring the whole velocity of the steam by such peculiar injet and its
clear reaction or reissue, and how its full effect might be impaired or wholly
neutralized, as just described, I found myself possessed of a new method of
applying the power of steam by its velocity alone, and this became the germ
or principle of my improvements in the steam engine; for to carry it out I
had only to invent such machinery as would give me this double power in
the same direction of motion, without deduction for the unbalanced pressure
in the experimental arm (d), to counteract the full effect of the whole force of
the velocity, and also without loss of power from another source, that of any back
action or impingement of steam against the back of the cavitynext insuccession.
The following, therefore, is a description of the engine and apparatus by which
I propose to effect these objects, the Drawings of my improvements in steam
engines being contained in five sheets, lettered Drawing A, B, C, D, E.
Drawing A. Fig. 1 is a section of a case (a, a, a, a,) shewing a wheel (b)
fitting within about half an inch all round, and revolving therein with
the axle (c). This case for a high-pressure engine may be made of cast
or sheet iron of suitable thickness to resist the pressure of the atmosphere
caused by a partial vacuum from the rapid action of the steam wheel. The
whole of the inside I prefer should be polished, or made perfectly smooth, to
For a
prevent friction of the used steam when it reissues from the cavities.
condensing engine the case must be made strong enough to resist the atmospheric
pressure at those parts where jets of steam are admitted. Several cavities
(d, d,) are made with or attached to the inside circumference of the case for
the purpose of receiving the used steam, and returning the same into the
cavities of the steam wheel; and where a double row of cavities are used
round the steam wheel, the rows of cavities on the case must be reversed
accordingly. These cavities round the case must be placed upon such
a. position to the cavities of the steam wheel that, on the used steam

page_text: issuing therefrom and rushing into the cavities in the case, it may be
returned therefrom into the cavities on the steam wheel at the same angle
as that at which the steam first issued from the jet pipes, and the used
steam will then, as the wheel revolves, be thrown out at the eduction
passage (e). The periphery of the steam wheel is formed by a series of cavities
all round of the same dimensions, shewn by the dotted lines, for the reception
of one or more jets of steam. The size of the cavities represented in the
wheel (b) is three quarters of an inch deep by one inch and a half long, and
half an inch wide, and which are better shewn on an enlarged scale by
Figs. II. and III., and are made in the following manner:-Pieces of copper,
of suitable thickness, are cut into dimensions of three and a half inches
long by one inch and three quarters wide, and bent in the form described
by g, h, i, Fig. II.; being from j to k two and a half inches long, from k to l
half on inch, and from 7 tom half an inch long. When a sufficient number to
go round the circumference of a wheel are so bent, they are to be united
firmly together at i by rivetting or otherwise, so as to make each cavity three
quarters of an inch deep from the point n, and when so formed all round for
the periphery of the wheel, each side is to be enclosed between rims of copper
or iron or other metal of suitable thickness, in the following manner :-Two
annular rims, each about one inch wide, are to be grooved at o,p,q, about one
eighth of an inch deep, of the precise form of the cavities for the same to be
accurately fitted therein, as shewn in Fig. III., Drawing A. One rim being
thus fitted to each edge or side of the cavities all round, the whole will
be securely fastened together by screw bolts or rivets passing through each
rim at the holes (r, r,) Figure III., and with one such fastening at least to
each cavity to prevent any steam passing through the interstices therein. The
series of cavities will then be complete, and will form the periphery of the
wheel, and can be attached to the nave by spokes or by a plain disc; or a
disc of the required strength and size of the wheel can be cast entire, with the
proper grooves at each side of the extreme circumference (if for a double
row of buckets), or with only one groove all round for a single row, and
these grooves can afterwards be cleaned out and the cavities fixed
therein, and thus form a very powerful and very cheap steam wheel. The
steam is admitted from the boiler by a pipe (s) sufficiently large to keep
fully supplied the circular steam chamber (t), from which the steam passes
along its several passages (u, u, u,) which terminate in nozzles of the required
area, placed as near to the periphery of the wheel as they can be without
touching and to conform to the circle thereof, as shewn at u, v, v, v, v ;
and it is important that each steam-way to each nozzle or orifice should

page_text: be not less than seven times the area of such orifice. Figure IV. (a)
shews a section of the steam chest (t in Figure I.) cut through at the
line w, w, and shews also a section of the case and view of the steam
wheel. The inside of the back of the steam chest (a, a, Figure IV.) is
ground true and smooth, shewing the outlet (b, b, b, b, b,) for the steam,
which correspond with the steam passages (u, u, u, u, u, in Figure 1);
two thirds of an annual plate of metal (c, c, c, Figure IV.), ground to
work true upon the surface of a, a, is connected to the nave and spindle.
(d, Figure IV.) by the spokes e, e, e. The end of the spindle, which runs
through the nave of the said annular plate (c, c, c,) works in a bear to
keep it in the centre, as shewn at x in Figure I. This spindle runs through
the steam pipe to the fore part of the boiler if in a locomotive engine,
and terminates in a handle shewn in Fig. V., to enable the engineer to
regulate the admission of the steam. Those passages represented by dotted
circles(fffff, in Fig. IV.) are passages for the steam to reverse the engine,
whose entrances are stopped by the annular plate. The three passages
shewn open (b, b, b,) and the two passages represented by dotted circles
(b,b, Figure IV.) are to propel the wheel one way; and the other five passages
represented by dotted circles, (f,f,f,f,f, Figure IV.,) are to reverse the motion;
the two passages, shewn by dotted circles b, b, Fig. 1V., are intended to be
opened as auxiliary power, if required, to assist the train up inclined planes.
When the annular plate is moved to g, g¹, Figure IV. all the orifices are
closed, and the steam is entirely shut off from the wheel; when moved further
to the left, the number of steam passages (f,f,ff.f.) opened on the opposite
side of the steam to reverse the wheel, will be in proportion to the space
over which the annular plate is so turned to the left. The back of the
steam chest is thus divided into three equal parts, of which five passages
for steam to propel the wheel one way occupy the first part, five passages
for steam to reverse it occupy the second part, and the remaining third is
blank. At the front part of the engine the handle, when upright, will
shut off the steam entirely, as shewn by the word "stop" in Figure V.,
and will turn over a brass plate or index, having marked thereon on
one side I, II, III, IV, V, according to the number of steam passages
to propel the wheel, and on the opposite side I, II, III, IV, V, according
to the number of passages to reverse the wheel. On the index also
will be fixed two projecting studs (h, h, Figure V.), which will stop the
handle, and prevent the engineer opening two opposite steam passages
at the same time. The lower part of Fig. IV. shews the end view of
a wheel, having a double row of cavities on its periphery, made as before

page_text: described, but placed in opposite directions, to enable the wheel to be
propelled either way according to the direction in which the steam is
admitted through the passages in the steam chest, (t, Fig. 1,) as before
described. If the steam be admitted through the passages b, b, b, b, b, in
Figure IV., and u, u, u, u, u, in Figure 1, the wheel will revolve in
the direction of the arrows y, y, y, as drawn in Figures I. and IV., and
if admitted by the passages f, f, f,f,f, in Figure IV., to the last hole of
which the nozzle z in Figure IV. belongs, and of which passages f, f, f, f; Þ›
and the dotted lines in Fig. 1, drawn near the letters u, u, u, u, u, shew
the direction of the passages leading from the steam chest, the wheel will
revolve the reverse way in the direction of the arrow j in Figure IV. As
it is necessary to prevent the air from entering the case where the axle
k, k, Fig. IV. passes through it, and it is desirable to avoid the trouble
of stuffing boxes, I have the outside of the nave of the steam wheel ground
true and flat, and also that part of the inner surface of the case which touches
it, and by the same effort with which the air seeks to enter the partial
vacuum in the case will the sides thereof be pressed against the nave of the
wheel, and an air-tight joint be formed, which will always be self-adjusting,
and may be lubricated by small oil cups fixed on the outside of the case.
For the purpose of forming such air-tight joint the steam case must be
made of such a substance as will be just pliable enough to yield to the
pressure of the atmosphere. But in order that the surfaces of each may
wear equally at every part of contact, the circle of revolution must be kept
as small as possible sufficient only for the object, otherwise the attrition
will not be the same at every part, for the outer edge will revolve over a
larger surface than the centre, and wear more the greater distance therefrom.
But, kept within proper limits, my engine will possess a stuffing box of the
utmost efficiency with the least possible expenditure of power, and one that
requires no attention to keep in order, for the longer the wear the more
perfect will be the mutual adaptation of surfaces. The manner in which
the before described engine is set to work is as follows:-The engineer
will turn the handle shewn in Figure V., and the steam will pass from
the steam chest (t, Fig. 1,) through the passages (u, u, u,) and the other
two passages u, u, may also be opened to assist the engine to start (if found
needful) in direction of the arrows y, y, shewn in Fig. I., when the steam
will rush with its full power into the cavities of the wheel, and the whole
of its velocity be arrested thereby. These cavities must be set at such
an angle to its circumference most favorable to propulsion as will permit
the steam to re-issue therefrom in the opposite direction to its entrance,

page_text: rar-
without striking against the back of the cavity next in succession.
ticular attention must be paid in inclining the cavities, and in adapting
and fixing the jets of steam thereto, to preserve that particular angle as
will best effect this combination. By this peculiar direction of the injet
of steam, and its clear reaction or reissue, about double the effect is obtained
to its mere impact or impingement against a vane or flat surface, for all
the velocity of motion or impulsive momentum of the steam is thus arrested,
and by this application of it turned back, and the power so required to
totally change the direction of the steam is received in the cavities of my
wheel, which will revolve with all the available power of the steam, and
its extreme duty from expansion in the direction of the arrows y,y,Figure 1.
At starting, and before the wheel has attained its allotted velocity herein-
after described, the wheel will be exceedingly powerful; it will not only
receive the full effect derived from the velocity of the steam, but it will
be set in motion by the aditional power of the used steam, which will reissue
from the cavities of the wheel and enter the cavities round the case, from
which it will again be returned into the cavities of the wheel by action
and reaction, and thus be used over and over again until the wheel attains
a velocity greater than what remains in the used steam, or until it is thrown
off by the action of the wheel and its centrifugal force, in the direction of
the arrows e and z, through the eduction passage (e and 2), which in the
locomotive engine will form the blast pipe, as shewn in Fig. 1.
The Figures in Drawing A, to which the foregoing description refers, are
laid down to a scale of two inches to a foot, and are those proportions of my
engine which are intended for a locomotiveboilerwhich evaporates aboutsixty
cubic feet of water an hour at sixty pounds pressure onthesquare inch above
the atmosphere. Such a steam wheel, revolving at thirty-four thousand eight
hundred and thirty feet a minute, at about which velocity I prefer the
periphery of my engine at such pressure to revolve, will, I think, give about
the net actual power of one hundred and fifty-three horses, after deducting
for loss by the velocity of the steam wheel; and the same proportion of
partsandvelocity are applicable for any high-pressure engine on my principle
where the boiler evaporates the same quantity of water an hour at the same
Three jets of steam of the united area of 2.37 square inches;
pressure.
as shewn in the Drawings and Table herein-after given, are sufficient to
discharge such quantity of water.evaporated into steam power per hour, the
other two jets for propelling or reversing being intended only for auxiliary
power, for if used continually they would run off the steam too rapidly for
such a supply. The velocity of the steam wheel may produce a partial
vacuum even at the circumference, in which case the steam would flow
B

page_text: with a greater expansive velocity, and perhaps render necessary som
alteration in the proper speed of the wheel and in the table of velocit
herein-after given, but practice can alone determine this result with the
required accuracy. Though a boiler evaporate double or four times th
quantity of water an hour, the wheel itself need not be enlarged to tur
it to account. All that is required is an additional number of jets, whos
united areas shall be sufficient to discharge the steam for the power required
These jets must be placed round the wheel at the proper angles described
and additional cavities must be attached to the steam case inside to tur
back the motion of the steam in the direction of the wheel, and the
eduction passage must be then placed a little way after the last jet of steam
I can thus increase a high-pressure engine on my principle and plan to
any power required, from one hundred progressively to one thousand horses
without increasing the size or weight of the engine; and even in condensing
engines on my plan, the additional weight will not exceed ten tons for the
highest powers. The axle frame and cavities being made of suitable strength
and the boilers proportioned to the power required, by the simple addition of
more jets of steam (one to every one or to every other cavity if required),
the power of the engine may be encreased to the extent desired. The way
of supplying the steam to the jets may be varied by a belt or band of
steam of suitable capacity to supply them, and properly clothed to prevent
condensation surrounding the case, or it may be inside the case and inside
the wheel, and the wheel revolve round such belt of steam, in which case
the cavities on the periphery of the wheel must be made angular and
open at both ends, or of such other shape as will permit the steam to enter
at the inside of the wheel and be discharged at the outside; I prefer, how-
ever, the method described in the Drawings.
The way in which I connect my steam wheel to locomotive engines by my
"roller and wheel connection" is she wnin the Drawings,in Drawing Bofwhich
the following is a description:-The engine in its case, as before described, is
partly enclosed in the smoke box, the portion of which that protrudes is shewn
by (a) Figure 1. The smoke box is formed as usual, except that the two out-
side angles are bevilled off, as shewn at b. The wheels of my engine (c,c,c,
Figures I. and II.) are connected by a common straight axle (e), the
ends of which work in the usual bearings or plummer boxes, except that
such bearings for my engine are not connected with the springs, but have
room to play up and down in guides formed by the frame, as shewn by
ff, Figure 1. The driving wheels are of the usual form, except in having
the flanges wider and flat, as shewn at d, d, Figure II., unless I should
find it desirable to-apply to the wheels of locomotive engines the principle

page_text: of the inclined groove and spherical edge, which I call "the bevilled groove
and spherical tongue connection." To obtain greater adhesion, as shewn
in Drawing D, Figure IV., herein-after described, the springs g, g, g, are
elevated a sufficient height above the driving wheels, which are here repre-
sented as four feet diameter. These springs are confined by any convenient
arrangement of the frame, or as shewn by h, h, h, k, h, h, in Figures I. and
II., the ends of the springs being allowed to play in elongated holes or
slots, as shewn by i, i, Figure I. Beneath the springs, at their centre,
are attached thereto brass boxes or bearings, (j, j, j, Figures I. and II.,)
in which are fitted steel or other hard metal rollers, (k, k, k,) which rest
upon the widened flanges of the driving wheels before described, and
have full freedom to revolve in such brass boxes or bearings. The ends
of these boxes pass through the spaces made in the framing at 1, 1, 1, 1, 1,
Figs. I. and II., the sides of which spaces prevent such boxes from
moving in a horizontal direction, but permit them to play freely up and down
vertically, answering to the elasticity and variation of the springs (9, 9, 9).
The said rollers are so to project beneath the boxes or bearings (j, j, j)
as always to rest upon the wheels, as shewn in Figures I. and II., and
are to be confined to their ends in the said boxes by a projecting rim. A
section enlarged of the brass box or bearing j, j, j, and the roller k, k, k,
of Figures I and II., is shewn by Figure III., Drawing E. That portion
of the box at m which is directly over the flange of the wheel (n) is
slightly hollowed so as not to be in contact with the roller at that spot,
and the roller itself has two slightly projecting rings (0, 0,) round it at a
short distance from each side of the flange (") of the wheel. The object
of this arrangement is to permit those parts. (p, p,) of the roller which
are in contact with the brass box or bearing (r, r,) to be lubricated
in any convenient way, or as shewn at q, q, and at the same time to
prevent the oil from destroying the adhesion or friction of that portion
of the roller which is in contact with the flange of the wheel. To the
inside of each roller is fixed a crank (r, r, r,) Figure II., Drawing B
which may either be composed of springs, as shewn in the enlarged Drawing
of Fig. IV., Drawing E, or without them, when a spring connecting link
will be used, as afterwards described. A connecting link (s, 8, 8, s,) Draw-
ing B, which I call a compensating link, joins this crank to another similar
crank, (t, t, t,) which last crank is fixed to the axle (u, u,) of the steam
wheel contained in the case (a). This mode of connecting the steam wheel
by the division of the axle, and its reunion or junction with the rollers
by means of cranks and spring compensating links, will save the steam

page_text: wheel from any derangement, jar, or concussion, and is an adjustment
which will enable the engine to work smoothly, durably, and, uniformly. The
axle is kept in its proper position by the standards (v, v, v,) Figures I.
and II., which are firmly fixed in the frame-work of the engine. The
Boiler and furnace are fixed in the usual manner to the frame of the
locomotive, and through the medium of the springs (g, g,) and rollers (k, k,)
are supported on the flanges at the upper part of the driving wheels, as shewn
in the Drawings Figures I. and II., instead of being supported on the axles
in the usual way. Now if the axle (u, u,) is caused to revolve by the steam
wheel either way that is desired, it will give, through the medium of the
cranks and connecting links before described, the same rotatory motion to
the rollers; and by the pressure thereon caused by the weight of the engine,
these rollers, being in contact with the periphery of the driving wheel, will
have the same frictional power by contact or adhesion to the wheel as the
wheel has to the rail, which will necessarily cause the wheel to revolve in a
direction opposite to that of the steam wheel and rollers, and with a speed
proportionate to the difference between the diameters of the rollers and
driving wheel, and thus the locomotive will be propelled by the pressure of
the axle ff. The proportion between the diameters of the driving wheel
and rollers must be determined by the speed desired to travel, and by the
rate at which the steam wheel revolves. In the Drawings the driving wheel
is shewn to be four feet diameter, and the roller three inches and two tenths;
and if the periphery of the steam wheel revolve at about thirty-five thousand
feet a minute, such proportioned rollers will propel the locomotive at about
thirty miles an hour. The boiler will be supplied with water by the usual
pump, to be worked by an excentric upon any one of the axles of the wheels.
The other parts of a locomotive frame and appurtenances for my engine do
not require description, as they may be made in the usual way.
In the front of the locomotive engine I place a screen, shewn by the dotted
lines 2, 3, 4, in Figures I. and II., Drawing B, the frame of which may be
composed of wood or iron, and covered with sheets of metal; the form is shewn
by the dotted lines 2, 3, 31, 4, 41, 4", in Figure II., and the side view is shewn
in Figure I. by 2, 3, and 4; and this screen may be fastened to the frame-
work of the engine at any convenient places, such as at 2, 3, and 5, in
Figure I. The object of this screen is to lessen the resistance of the atmo-
sphere which the engine now receives, and to turn that which it must still
receive to a useful account, an advantage which is obtained by the atmosphere
pressing on this screen, and by giving greater adhesion of the wheels to the
rails, which will also render the engine less liable to pitch; aud these advan-

page_text: ages will be obtained in proportion as the screen is allowed to approach a
horizontal position; for instance, if the chord of the arc of the screen forms
an angle of 45° with the plane of the rail, and the resistance over the whole
of the engine without the screen amounts to three hundred pounds, the engine
will only receive a resistance of one hundred and fifty pounds, and the
remaining one hundred and fifty pounds would be thrown in a vertical
direction, and be in favor of the adhesion of the wheels, and tend to prevent
the engine jumping off the rail.
For steam navigation or other condensing engines I apply the steam
upon the same principle, and use the same kind of steam wheel as for
locomotive engines, but with only one row of cavities round the peri-
phery, and I add thereto the following eccentric rotatory air-pump :-
Figure II., Drawing E, represents an outside view of a hollow barrel or
cylinder, where a and b are flanges cast thereon to attach it to the condenser
At each end of the barrel are
and hot well, as herein-after described.
also two flanges (c and d) cast thereon, to which the two caps (e and f),
a side view of one of which is shewn in Fig. VI., are bolted. Through this
barrel passes the axle of the steam wheel before described, being enlarged at
that part within the barrel in a manner shewn at g, Figure I., and which
forms an eccentric, shewn by hand i, Figures VII. and VII. The parts
jand k, in Figure I., are a section of the barrel just described, and I, I, that
of the axle of the engine. The caps e and f, before described, will be ground
as water-tight as possible to the shoulders and axle at m, m, m,m, in Figure I.
Figure VII. shews a transverse section of the barrel and excentric action,
as possible
which axle will be made to revolve with the part n, as nearly
water-tight with the inside of the barrel; this barrel has two openings
lengthways through its whole extent, shewn at o and 2, Figure V., which is
the back view of Figure II. The said two openings will take the direction
shewn at 7 and 1, Figure VII., in one of which (screwed to the solid part
which makes the division between the said openings) will be a piece of
metal to form an elastic spring, as shewn at s, running the whole length of
the barrel, the edge of which spring gently press upon the surface of the
eccentric axle, as shewn at t, t, Figures VII. and VIII. The excentric axle
must be so true, and the spring be so adapted thereto, that they may form
together an air and water tight joint, and thus prevent any communication
between the two openings q and r, or between one part of the barrel and the
other. Figure VIII. represents the condenser u, and hot well v, w being
the eduction passage from the steam case containing the steam wheel, and
the injection pipe. The section of the before-mentioned air pump is shewn
at y, screwed in its proper place to the side of the condenser, with the open-

page_text: ings q and r fitting to corresponding passages z, z, leading from the condense
and also to the hot well.
The way in which my eccentric rotatory air pump will act is as fol
lows: The excentric axle partaking of the motion of the steam wheel in
the direction of the arrow (n), Figure VII., the space A will gradually
become enlarged, and the space B be contracted, and the water and ai
will pass through the passage q, to fill the vacancy, whilst the water and
air contained in B will be urged through the passage r, by the excentric
taking the position as shewn in Figure VIII.; and thus the air-pump will
continue its revolutions, and expel the injection water and air into the hot
well v.
When the excentric is in the position shewn in Figure VIII, the
spring will be pressed back into the passage (Figure VII.), as there shewn,
allowing the excentric axle to pass round. In the hot well v, a long narrow
flap (2), running the whole length and working upon a hinge, will act as a
valve to the passage r, and prevent air or water from passing from the hot
well to the air pump when the engine is stopped or stationary. I consider
that the following proportions are about those dimensions which will be
required for an air pump on my plan:-For a condensing engine which is
working off a cubic foot of water, evaporated into steam, a minute; namely, the
barrel should be about eighteen inches long, four inches in diameter in the
bore, and the excentric about three and a half inches diameter, which leaves
an extreme space of half an inch for the expulsion of the injection water and
air into the hot well, the axle making not less than about three thousand
revolutions a minute.
Drawing D represents my method of connecting my steam engine
with a paddle-wheel shaft for steam navigation, or with other machinery
requiring a slower motion than my steam wheel, which Invention I
also call "the roller and wheel connection." Figure 1 (a) represents the
case containing the steam wheel before described at Figure 1, Drawing A,
having only one row of cavities round the periphery thereof; and Figure II.
shews Figure I. cut through at the line. The case is here shewn to be
made stronger by outside ribs (b, b,) if found necessary, and which case is
kept steady by suitable framework c,c, and fastened to the foundation plate (d).
The eduction pipe (A) leads the steam from the steam case to the condenser
(B), where it is condensed in the usual way by injection, from which it is
withdrawn by the air pump (c) and discharged into the hot well (D), as
described in Drawing E. The pipe E is to carry away the waste water from
the hot well, and F is the pipe to supply the feed pump, which can be worked
by an excentric on the main shaft. The steam is let into the cavities of the
steam wheel at H, on the opposite side to the pipe A.. Figures VI. and VII.

page_text: represent transverse and longitudinal sections of the termination of the large
supply pipe H, conveying the steam from the boiler to the steam chamber I.
From this chamber the steam will rush into the cavities of the steam wheel
through the passages 1, 2, 3, 4, 5. The slide J will be worked by hand by
the rod passing through the stuffing box K, and will open or close as many
passages as are desired. The axle of the engine or steam wheel passes through
the air pump (C) before described (and in Drawing E), and works the crank
(e), which may be connected to the other crank (g) by a spring link (f),
which I call a spring compensating link, as shewn in Figures IX. or X.,
Drawing E. The crank (g) gives motion to a short axle (h), which passes
through a bearing (i, i,) herein-after described, and terminates in the roller j.
This roller is received into an iron hollow k, cast or otherwise made in the
circumference of a larger wheel (1), as shewn in section in Fig. 1, and which
wheel is fixed upon the paddle shaft (m) in steamboats, or on the main shaft
of machinery in general. The part of the framing (n, n,) shewn in section
Fig. 1, will support a bearing at its upper part o, for the main axle, and will
have an aperture at its lower part (p) to receive the moveable bearing (i, 1).;
this moveable bearing must be so made as to receive the axle (h) firmly and
securely, and to fit the aperture (p, Figure I., and p, p, Fig. II.), and be
made to keep its position laterally by a fillet shewn by the dotted lines q, Q, 9, 9,
Figures I. and II., but it must be allowed sufficient room to play vertically
up and down, as it may be elevated or depressed by the rods (", ", r,) Figures
I. and II. These rods are firmly fixed in the bearing, as shewn at 8, 8, 5, the
upper parts of which rods will go through the deck in steam vessels, and be
fitted to each end of a sufficiently powerful spring (t, t, Figure III.), and
through this spring will pass a broad threaded and powerful screw, which
will be turned by a handle or lever as represented at u, v, v, Figure III. By
turning this handle or lever the screw will elevate or depress the spring, which
through the medium of the said rods (r, r, r, r, r, Figure I., II., III.,) will
elevate or depress the bearing (i), the axle (h,) and the roller j, Figure I. ;
by this means the roller ; will be brought in contact either with the upper
part of the hollow (k) of the large wheel at w, or with the lower part at x,
Figures I. and II.; and by frictional adhesion or contact will turn the wheel
(/) one way or the other, as the vessel or machinery to be moved thereby is
required to be propelled or backed. The spring t, before referred to, will keep
the roller (j) sufficiently in contact with the wheel (1), and yet allow by its
play sufficient compensation for any slight inequality in the periphery of the
said wheel. If preferred to have this arrangement for propelling, easing,
or backing the vessel below deck, the principle is capable of as easy
arrangement below as above deck. The space between the upper part of

page_text: the bearings of the axle (m) and the under part of the screw box (u),
Figure III., will be occupied by a sufficiently strong prop or support z, z,
Figures II. and III., for the screw (u) to fit in, and thus prevent any strain
apon the bearings. The paddle wheels or machinery may, by this arrange-
ment, be eased or suddenly stopped and reversed, whilst the steam wheel
continues its maximum velocity, and yet without concussion or derangement,
which would otherwise be produced by a rapid speed being suddenly arrested
or imparting a portion of its velocity to matter at rest. For though the steam
wheel continue its utmost velocity, it will only impart the required motion to
the paddles or other machinery gradually and smoothly; for the great wheel
will slip for a while, until its inertia of rest is overcome, and it obtains its
uniform speed ; and should a heavy sea strike the paddles, or any other
unlooked-for impediment (such as masses of ice or wood suddenly arresting
the paddles), neither strain nor concussion can be produced as in the present
engine, for my steam wheel will still continue its smooth and easy velocity,
whilst the large wheel will accomodate itself to the obstruction by slipping for
the moment, until the unwonted resistance be removed, and only that resist
ance proportioned to the power is restored which was originally calculated
the engine would have to overcome, and when the vessel is stopped all the usual
chances or danger of the boiler bursting through the safety valve getting out of
order will be removed if the steam wheel allowed to continue its motion, for
it will then act as a safety valve, and carry off all the steam that would other-
wise accumulate, and pass off at the usual safety valve, for it is chiefly when
the vessel has been stopped, or just previous to being again started, that so
many lives have been lost by the boilers exploding. In the numerous stoppages
on the river, this will save the engineer the frequent attention to the injection
cock, which, once turned at starting, may continue till the vessel reaches its
destination. One action only is required for stopping or reversing the vessel
with my engine; three with the present, the steam supply valve, gear, and
injection. The supply and bilge pumps can be attached to the main shaft, or
worked in any of the usual methods familiar to engineers.
Where the plain surfaces, before described, for the adhesion of the roller to the
wheel may not be sufficient for purposes of great power (on account of too much
strain on the bearings necessary to obtain the required contact being found ob
jectionable), I propose to use a modification of the principle before described.
as well for locomotive engines, navigation and other purposes, an arrangement
which I call "the bevilled groove, and spherical tongue connection," the
plan of which is better shewn in an enlarged Drawing. Figure IV. Drawing D
part of a roller (a), is shewn, having one, two, or deep more grooves (b, b,
turned round it, the sides of which grooves are beyilled, or approach each

page_text: other towards the bottom of the same, as shewn in the Drawing, Figure IV.,
c, c, c, c. The circumference of a wheel (of which part only is here shewnatd),
which is to be turned by this roller,) has a round it one, two, or more projections
e, e, truly spherical at their edges, and made to fit into the grooves in the roller,
and which will place opposite portions of these spherical edges in contact with
the inclined or bevelled sides of the grooves, as shewn by c, c, c. c. The follow-
ing is a description of this arrangement, the principle of which Figure V. will
illustrate, being found on the principle of the wedge or incline plane:-The side
(f) Fig. V. represents the inclined or bevilled side of the grooveb, Figure IV.,
which is in contact with the spherical edge of e, the perpendicular g of Fig. V.
and base forming a right angle triangle, of which f is the hypotheneuse. By
this form of contact the degree of pressure which causes e in Fig. 4 to advance
to 6 will be increased, as relates to the point of contact at c of the bevil of the
groove or hypotheneuse of the angle, in proportion as the side g exceeds the
base / in Figure V., by which plan adhesion may be obtained to any required
amount by vertical pressure of a comparatively small degree. For instance, if
the adhesion or contact required between the roller and the hollow wheel; for
steam navigation or other purposes, was 10 tons, by making the perpendicular
9 (Figure V., Drawing D,) exceed the base h 10 times, (that is, let g be one
inch and a quarter, and one eighth of an inch,) the axles and bearings would
only bear a pressure of one ton. By applying this principle to the tread of the
wheels of locomotive engines, the adhesive power may be so increased as will
enable them to surmount gradients so steep as to be impossible to be sur-
mounted by the present engines, whilst the tractive power may be increased to
the required amount by letting on more jets of steam, as before described. If,
for instance, the adhesion between the wheel and rail were ten tons before this
principle were applied, it would be increased to 100 tons by using the pro-
portions just mentioned. By having, therefore, auxiliary engines, with wheels
so made ready to draw the trains up steep inclines, may prevent the use
of stationary power, and the necessity in many cases of making such easy
gradients at so great a cost. In so applying this principle, the wheels must be
made with a hollow in the periphery, in the same way as the rollers are
described in Drawing D, Figure IV., and the rails will form the tongue.
Figure IX., Drawing E, represents myspring connecting compensating link,
for the cranks of my axle and roller to allow the boxes or bearings to be
elevated or depressed, and is formed of two elliptical'springs (a and b), which
are joined in the usual manner at their extremities, and the centres of the
springs are attached by a moveable joint to the extremities of each crank at
c, d, separating them at about an angle of 60 degrees.
Figure X.,Drawing E,is another kind of spring, which I call an elbowspring

page_text: connecting link (which I prefer), for the same purpose, namely, to prevent any
jar or concussion, and to compensate for any irregularity of motion affecting the
engine shaft. The partse and fare formed by a seriesof spring plates fastened
together in the usual way, and increasing in strength towards the end (g),
where they are strapped and bolted together in the position shewn at Fig. X.,
and the ends and i have eyes for the purpose of being connected to the cranks
before mentioned; should these cranks be found to revolve so quickly as to
'cause much atmospheric resistance, they may be inclosed in a circular case to
revolve with them; and in the condensing engine on my plan, where the steam
wheel will revolve with a much greater rapidity (as herein-after shewn), the
cranks may revolve in an air-tight chamber, communicating with the condenser,
by which arrangement they will revolve in vacuo. But in the whole engine,the
air-tight stuffing boxes need not exceed two,the condenserandair pump being
'placed on one side of the steam case, and the crank chamber on the other.
Drawing C, Figure IV., V., VI., represent sections, and an end view of
my improved nozzle for supplying steam to the wheel on my principle, which
if only one large supply pipe be used to increase or diminish the power of the
wheel must be so formed, instead of as a throttle valve. Figure IV., which is
a plan in section, has at the immediate orifice inside a truly spherical hollow,
shewn by a, which continues past the orifice to the point 6, into which
spherical hollow is ground true and fitted a segment of a circular piece of
metal C, which is connected with the small spindle d, which terminates in a
handle or connection outside, which can be connected with a governor, to con-
tract or enlarge the orifice, according to the wants of the machinery, or be
turned by hand to shut off the steam entirely. Figure V. shews a sectional
side view of the same, where C is the segment of the circle d, the spindle
passing through a small stuffing box (e), and terminating at any convenient
distance by the handle f. Figure VI. represents an end view of the same, and
shews the whole size of the orifice g, g, and two different positions of the con-
tracting segment by the dotted line h, and the dark portion i. The object of
such a nozzle is to contract or enlarge the passing for the steam at the imme-
diate outlet or orifice, for if the contraction be higher up the pipe the steam
would be so diminished in pressure at the orifice as to lose a great portion of
its impulsive velocity.
Drawing C, Fig. 1, is the form of arm I found to give more power in
engines on Hero's principle. Instead of the straightarins a, b, I use serpentine
arms, shewn at c, d, e, f, where the parts from c to d, and from f to g, partake
of the circle of rotation another line, and where the parts form d and to the
centre e are made to form an easy curve, the pipe or hollow where the steam
runs along gradually enlarging in the area to the centre e.
The object of

page_text: such an arm is to keep the part which receives the reaction or unbalanced
pressure of the steam as far as convenient from the orifice of discharge, forby
this arrangement I found that I gained one third more power. Insdie the
case in which the arm revolves cavities are shewn fixed all round to receive
the steam on its issue from the arms, to return in the direction of motion.
But I describe this form of engine simply because it formed part of my experi-
ments, not as forming any part of my present Invention,-though I do not
think it has been previously used.
The following Table of pressures will shew the proper force of, or impulsive
effect from the simple expansive velocity of steam rushing, on my principle,
into a stationary cavity uninclosed, in the open air of the engine room. The
diameter of the supply pipe was one inch, and five feet ten and a half inches
long, with one bend, and its termination. The orifice of discharge was three
eighths of an inch in diameter, or about the ninth of a square inch. Thie
several pressures of steam in the boiler were throughout half a pound more,
this half pound being allowed for condensation, et cætera.
TABLE of the force of the injet of steam in a stationary cavity uninclosed and
exposed to the atmosphere, and its re-issue therefrom, calculated upon
the square inch, from actual experiment given by an orifice of about the
were inch
The fact of a power being given out from the expansive velocity of steam,
when properly arrested, of more than double what would seem (primâ facie)
to belong to it, as indicated by the pressure in the boiler, is consistent with
the additional force acquired by other bodies, which the following case may
illustrate: If a ball weighing sixty pounds be resting on the earth, it will
press with the force of sixty pounds; but let it fall from such a distance that
on its touching the ground it shall have acquired a certain velocity, it will
strike not merely with its original weight of sixty pounds, but with the
accumulated force due to the velocity acquired in the descent. Now let the
ball at rest represent the initial pressure of the steam at rest in the boiler, and
the acquired force of the ball represent the expansive power of the steam

page_text: which gives it that extraordinary velocity when set at liberty and allowed to
expand lineally, and though there is no resemblance between the velocity
acquired by attraction or gravity and the velocity acquired by repulsion, the
results of more than the initial power being given out are analogous. The
cavity with which these great effects were obtained was three quarters of an
inch square and deep, which give an area about five times that of the orifice of
the jet. It was placed on a balance six feet high, resting on knife edges made
with great precision, and accurately weighted to mark the index. But the
cavities for practice need not be more than sufficient to receive the full jet of
steam, which will keep the wheel (even for the greatest powers) very compact
and if the base be twice the area of the jet, that is ample, for no additional
power is gained by the steam expanding over a larger area, expansion from an
unobstructed current of steam being already obtained from its velocity. The
above results were obtained, as I have stated, from a cavity at rest; but when
the wheel revolves all the force of the steam from its velocity cannot be trans
ferred to the wheel, and the power will consequently fall off in proportion as
the velocity of the wheel approaches the expansive velocity of the steam. But
owing to the extreme velocity of the steam, and the extraordinary force given
thereby, (being more than double the pressure in the boiler, indicated
by the guage,) a sufficient proportion of the power may be deducted for
the speed of the wheel and for friction, and yet leave such clear available
effect as will, with the same consumption of fuel and pressure, more than
double the duty of locomotive engines, exceed that of the best high-
pressure engines, and equal (if not exceed) the duty of the best Cornish
condensing, lifting, or marine engine. For though my deductions, when
compared with those allowed for friction and other losses of the present
engine, may seem to exceed them in some cases, they do not, because the
steam in my engino, having no piston to overcome, is expanded as low as the
atmosphere (as the Table shews) in high pressure engines, and in condensing
engines the steam will be expanded to the vapour point, or state of condenser
vacuum. It is, therefore, from these extreme expansive duties that my deduc-
tions are taken, and are constant; whilst those of the present engines are taker
from the expansive duty, where the steam can only be expanded to a much less
degree, varying according to the pressure of steam and friction of the piston and
other parts to be overcome. By thus applying steam by its velocity, it car
find its own equilibrium, and give out its whole expansive power in so doing
whilst such an extreme degree of attenuation being impossible on the present
system, some power must necessarily be thrown away. The rate at which the
pressure falls of or increases is as the squares of the expansive velocity of the
steam, as shewn in the following Table.

page_text: Column 1is the pressure of steam in the boiler above the atmosphere. The
2nd Column is the expansive velocity of the steam in feet per minute, at which
that steam will issue to the atinosphere, founded on the experiments of
Mr. Banks, given by Dr. Gregory in his Mechanics, vol. 1, 3rd edition, 1815,
p. 518, 519. Column 3 is the force, in pounds per square inch, of the inject
and reaction of the steam, on myprinciple, from a stationarycavity,due to such
velocity, as found by my experiments, by which I ascertained that the third
Column wouldvaryas the squaresof the velocity (or second Column). Column 4
is the velocity, in feet per minute,atwhich the cavities of thewheel recedefrom
the steam, that is, the velocity of the circumference of the wheel, which, when
deducted from the velocity of the steam (second Column), will leavethe velocity
or pressure at which the steam will rush into the cavities of the wheel when
revolving at the speed of thefourth Column, and willgive the fifth Column. The
sixth Column is the square of the second, and the seventh Column is the square
of the fifth. Nowas the square (Column 6) of the expansive velocity (Column 2)
is to the force (Column 3), so is the square (Column 7) of the difference
(Column 5) to the diminished force in Column 8, which, when multiplied by
the velocity of the wheel (Column 4), and again by the area in square inches
of the orifices of discharge or jets of steam necessary to give issue to the steam
required for the power, will represent a power equal to the number of pounds
raised one foot high in a minute (Column 11); this, divided by Mr. Watts
estimateof a horse's power, thirty-threethousand pounds, gives the power of my
engine (Column12). Column 13 is the number of cubicfeet of waterevaporated
per hour under the pressure of Column 1, to give the power of Column 12.
This table was commenced by giving the wheel the nominal velocity of ten
thousand feet a minute, and calculating progressively as shewn to sixty-five
thousand feet a minute, to illustrate the variation in results at different
velocities, to shew the best speed of the wheel to give the maximum effect. By
this table it will be seen that the greatest results are obtained when the wheel
revolvesatpreciselyonethirdof the velocity of thesteam, orthirty-fourthousand
eight hundred and thirty feet a minute. At whatever pressure, therefore, the
steam may be above the atmosphere, thewheel must always revolve at one third
of the velocity of the steam to obtain the maximum effect. As regards the
area of the jets, the proportions necessary to discharge steam at different pres-
sures above the atmosphere vary inversely as the square roots of the densities
or pressures of the steam, that is to say, 2-37 square inches (Col. 10) being
snfficient to discharge a cubic foot of water a minute, evaporated into steam
under a pressure of sixty pounds above the atmosphere; as the square root of
sixty pounds is to 2.37 square inches, sois inversely the area of the jet required

page_text: to the square root of the given pressure. And this last law will also apply to
the areas of jets for steam rushing into a vacuum. The foregoing table
of velocities refers only to steam above the atmosphere, and to non-condensing
engines. My experiments relating to the expansive velocity of steam issuing
in the atmosphere agreed so nearly with those of Mr. Banks, recorded by
Doctor Gregory, that I have preferred taking those data which can be generally
referred to as a standard. But those data do not apply to the expansive
velocity of steam rushing into a vacuum, for there it requires, I found, an
expansive velocity infinitely greater than that in the atmosphere to give the
same effective force in vacuo as in the atmosphere, from equal pressures. It
is this increased velocity in vacuo that will give a duty in condensing engines,
on my plan, equal to if not exceeding that obtained by increments of expansion
by the present system. The effective force, however, is the same from equal
pressures, whether in vacuo or in the atmosphere; that is, with steam at seven
pounds above the atmosphere, and a vacuum of twenty-six inches of mercury
(or thirteen pounds), making twenty pounds, the same effective force will be
given in a stationary cavity in vacuo, as is shewn in the foregoing table, by a
pressure in the atmosphere of twenty pounds above it. It is the different
velocities of the steam in and out of a vacuum required to give the same effec-
tive force from the same pressures that so greatly vary; and consequently, when
my steam wheel revolves in vacuo, different laws are required to determine the
different results that will be produced. The best practice, therefore, for con-
densing engines on my plan will vary from that of high-pressure engines.
When using steam in vacuum the effect of that portion of the steam above the
atmosphere must be ascertained by the same rules as are given in the preceding
table of velocities, just the same as if it were used in the atmosphere. But as
regards the other portion of the total pressure-that is, the expansive velocity
of the steam below the atmosphere, or the state of the vacuum-the effect of
this must be found by another rule, the correctness of which I have not been
able quite to satisfy myself upon, being in the midst of further experiments at
the time my Specification was due; I found, however, a very near approxima-
tion to those proportions which would be given by the squares of the state of the
vacuum encreasing or decreasing by this law, that is, taking the atmospheric
point at zero, and every variation between the atmosphere and the state of the
vacuum encreasing towards a perfect vacuum, the expansive velocity would be
by this law as the squares of such variations of vacuum.
If this be the case,
then the effect of the injet of steam, and its re-issue from a cavity, vary as the
square root of the expansive velocity of the steam, and the best velocity of the
wheel will in such case be two thirds of the expansive velocity of the steam.

page_text: To ascertain, therefore, the total effect in condensing engines, the effect of the
steam above the atmosphere, found by the former table of velocities as before
described, must be added to the effect of the expansive velocity of steam below
the atmosphere, and the sum will be the whole power, and give the duty of
expansion for any pressure and state of vacuum when multiplied by the velocity
of the wheelandtheareaofthejetsofissue. Thisduty will encrease rapidlyaccord-
ing to the vacuum, as it is well known the duty does by the extent of expansion
in the present engine. That the expansive velocity of steam in a vacuum is so
much greater than the velocity of steam in the atmosphere, is shewn by my
experiments by the following fact, that a state of vacuum equal to twelve
pounds and a half, with steam at atmospheric point, gave the same forcible
effect by injet in a stationary cavity in that vacuum as steam at twelve
and a half pounds above the atmosphere did in a stationary cavity in the
atmosphere, though in the latter case nearly double the quantity of matter
was injected; so that if the expansive velocity of steam in a vacuum had not
made up the difference of effect by the considerably encreased velocity of a mass
only half as great, the effective force given out could not have been the same.
In the case then of steam above the atmosphere, the expansive velocity of
steam is as the square roots of the pressure, but in a vacuum it will vary as the
squares of the state of the vacuum, assuming the correctness of my last class
of experiments, and the inject of steam in the cavities follow in the former case
the laws of the squares of the expansive velocity of the steam, but in a vacuum
the injet or effective force will vary as the roots of the expansive velocity of
the steam above the atmosphere, therefore the wheel will revolve at one third,
and in a vacuum at two thirds of the expansive velocity of the steam, to give
that mean of velocity and power as will produce the maximum effect.
I will and now conclude with a few general observations on my engine and
the present, as relates to the principle and advantages of each in a scientific
view. The principle of my discovery depends for its verification upon a very
simple but universal law of nature before referred to, and which, when noticed,
the mind immediately recognizes as a truth in science applicable as well to steam
as to all other bodies, fluid or solid, independent of its confirmation by my
experiments. This law is, that all motion is power,-power in proportion to
the velocity of motion, and to the amount of its beneficial transfer to the
medium of communicating it. Now, whatever body has a momentum or
motion given it, greatly exceeding that of the surrounding medium, whether
it be a cannon ball, an uninterrupted current of steam, or an air blast from a
furnace or from a blow-pipe, it cannot impart laterally any portion of that force
which it derives from the velocity imparted to it. Its force lies only in the line

page_text: of its direction, in which, and in which only, it must give out the same
power as it received, and to obtain the whole force from bodies so moving they
must be arrested before any part is lost by distance, or at that point where the
different nature of the body is found to impart its greatest force. Steam at
sixty pounds above the atmosphere, the pressure at which it is generally used
in locomotive and other high-pressure engines, has an expansive velocity
exceeding one thousand seven hundred and forty-one feet a second, which is
greater by about five hundred feet a second than the rate at which a cannon
ball is most beneficially expelled. Thus, the speed is about one hundred and
four thousand four hundred and ninety feet a minute, and six million two
hundredand sixty-nine thousand fourhundred feet, or one thousandone hundred
and eighty-seven miles six hundred and eighty yards an hour; and even at the
atmospheric point only, when rushing into a vacuum, its expansive velocity
is still greater, so infinitely exceeding the speed of the strongest hurricane, we
can compress this.immense expansive power, and making up in its far greater
intensity what the wind has in surface, we can employ it by a controulable
machine successfully to blow and contend against winds and tides. An unob-
structed current of steam then rushing forward at this wonderful velocity must
necessarily possess a surprising force from velocity, and cannot, from the very
nature of motion, expand equally in all directions, laterally as well as lineally,
or its great velocity would not exist. To obtain its expansive powers in all
directions its velocity must be first and immediately destroyed by cutting it off
before its power is expanded lineally. This error in science is done by the
present system; and to make up in power what is lost in velocity, immense
areas of surface are necessary, which has given rise to all the complexity of the
modern steam engine, and to an immense mass of ponderous and useless
matter, requiring so much valuable space and tonnage, simply because the true
properties of steam have never before been discovered, and the beautiful
simplicity of nature departed from. It is now apparent, by my table of pres-
sure, that the natural force and condition of steam is velocity; and as simplicity
is the perfection of science, this can only be arrived at by ascertaining the true
properties of those agents which are placed at our command, and applying them
in pursuance of those simple laws which regulate their existence; whereas the
present engine is in harmony with no motion in the universe, but stands alone,
a singular departure from the laws of nature. But we now see how simply
she acts in this great power, as in all things, and how much more in harmony
with all her known laws is this discovery, and the transmission of steam power
by its velocity by a machine as simple as the water wheel; even in my condensing
engine, where there is an air-pump, and the steam is expanded lower than in the

page_text: best Cornish lifting engine (owing to the absence of the piston to overcome),
there is neither expansive gear nor beam, nor excentric, nor slide, nor connecting
rods, nor valve moved by the engine, nor complicated machinery of any kind.
A pipe, a wheel, and an axle, enlarged at one part and enclosed, transmit in
the simplest way the extreme duty from expansion and form the whole steam
engine, which is self-adjusting; and the longer used the more smoothly and
equally will the parts wear, and the touching surfaces become adapted to each
other, compact, simple, and durable, scarcely liable to derangement. The
total weight of a marine engine of three hundred and twenty horse' power, on
my plan, will not amount to the weight of the duplicate parts alone (fifteen
tons) of the engine of the same power of Her Majesty's ship "Cyclops," thus
saving one hundred and twenty-three tons for additional stowage, and even for
an engine of one thousand horses power the total weight will not exceed twenty
tons. For the great purposes, therefore, of steam navigation and inland transit,
my engine is particularly applicable, for in the latter the speed of travelling is
limited by the present reciprocating engine wasting so much fuel at high
velocities. As an elementary machine, possessing a mere rotatory motion, I
do not attribute to my engine any superiority over a reciprocating engine of
slow motion as a means of communicating power as a substitute for the crank.
But though there is no loss of steam power in the crank transmitting that
power to the machinery, the application of steam to produce a reciprocating
motion is radically unsound in science as a principle, for it is only adapted for
a slow motion of reciprocation. The Cornish engines are the slowest in the
world, the speed of piston averaging sixty feet a minute, and these do the most
duty of any in the world. When this speed is increased to two hundred feet a
minute, as in the marine engine, the duty falls off more in proportion to the
difference of pressures, expansibilities, and boilers; or at least, when the speed
of piston is further increased to five hundred feet a minute, as in the locomo-
tive engine, there is found a still greater loss in duty, as the steam cannot be
fully expanded (as by the new system), and one half of the power is consumed
in overcoming the resistance of the used steam that cannot escape fast enough,
and thus one half of the fuel is wasted. To increase the speed of the piston to
seven hundred feet a minute, to travel faster, would cause so great a waste of
fuel as to become impracticable; whereas with my engine the speed is only
limited by curves and atmospheric resistance. It is on this comparison again
principle with principle, that the application of steam by velocity is found to be
sound, because equally advantageous at whatever speed the machinery is
required to be driven, and for whatever purpose; whilst the present system is
upsound, be cause it can only be used to the greatest advantage forone purpose,

page_text: and that at so slow a speed as to be inadequate to the present requirements of
civilization. The science and facilities of travelling are therefore in advance of
the means, and these I believe my engine will supply. The best effects will
be given by my engine in proportion as the three following requisites are com-
bined: First, in proportion to the quantity of motion abstracted from the
velocity of the steam, and beneficially transferred to the wheels, and the used
steam then got rid of. Now the greatest effort from the impulsive velocity of
the steam is only obtained by arresting its velocity before any of it is expended,
and by entirely changing the direction of its motion, and returning it parallel
to its advance, for if the jets of steam be so directed either that any part of its
volume still continue in the same direction in which it issues from the jet, or if
the steam be diverted in any other line than that parallel to its advance, soin
proportion will be the loss of power, as shewn by the experiments before
described. Secondly, in proportionas the jets ofsteam and the cavities approach
a tangent to the circumference of the wheel, and yet permit the used steam to
reissue without striking against the back of the cavity next in succession.
Thirdly,inproportionasthe wheel revolves at that velocity which, the two former
conditions being observed, will give the maximum effect. The foregoing tables
and these explanatory remarks are given to assist the public; for I have thought
it right, in bringing forward a new principle of steam power and a new appli-
cation of it, to afford all the information I possess (or believe I possess)
calculated in a scientific view to explain the discovery, and to assist in
carrying it out.
Having, in pursuance of the proviso of the said Letters Patent, given "a
particular description of the nature of my said invented improvements, and
in what manner the same are to be performed," I will now define the extent
of my claims.
I claim the exclusive use of my Invention, as before described, namely, an
engine or wheel with cavities on the circumference placed as above described
when moved by steam. I do not claim any of the separate parts of my high
pressure or condensing engine and apparatus, all or some of them being well
known; but I claim the same in combination and in use for the purpose of
carrying out practically and efficiently my discovery of the natural force and
effect of the simple expansive velocity of steam.
I also claim the exclusive use of two or more jets of steam to increase or
diminish the power of my steam wheel, as distinguished from the present
system of enlarging the capacity of the cylinders of reciprocating and other
engines.
I also claim the particular method of reversing a steam wheel by means of

page_text: the double row of cavities placed in opposite directions, as shewn by the
arrows on the cavities of the wheel in Sheet A, Figure I. and IV., as well in
locomotive as in all other engines.
Also I claim the exclusive use of the "roller and wheel connection," as
above described, for the purpose of connecting and disconnecting my own or
any engine of rapid rotary motion with and from the machinery to be moved
thereby at a slower rate.
I also claim the exclusive use of "the bevil groove and spherical tongue
connection," as above described, for the purpose of obtaininggreateradhesion,
and to apply the same principle to wheels of locomotive engines; though I do
not claim as my Invention the communication of motion by plain surfaces, nor
by a simple bevilled surface taken separately and apart from my arrangement;
but I claim as my Invention the particular combination,andadjustment of the
parts as described.
I also claim, for steam navigation and other purposes, whether for paddle
wheels or screw propellers, the exclusive use of the moveable box or bearing
which supports the roller, and a wheel having a hollow in thecircumferenceto
receive the said roller; and the method of bringing the same at will in contact
with the upper or under surface of such hollow in the wheel as described.
I also claim the exclusive use of spring cranksandconnecting compensating
links for such purpose.
I also claim the exclusive use of the method of preventing concussion to
my steam wheel by suspending it in the manner before described, namely, by
dividing the axle and joining it again by means of cranks, and spring compen-
sating or other connecting links.
I also claim the method of so connecting or adjusting a rotatory engine to a
locomotive engine as that the roller connected with the axle, or the axle itself,
may rest upon the periphery of the wheel, and the weight of the boiler and
other parts may be borne on the periphery at the top of the wheel, through the
medium of the said roller boxes and springs, in the manner described, instead
of, as now, being borne by the axles of the wheels.
Such my Inventions being, to the best of my knowledge and belief, entirely
new, and never before used within that part of Her said Majesty's United
Kingdom of Great Britain and Ireland called England,and Hersaid Dominion
of Wales, and Town of Berwick-upon-Tweed, and Her Plantationsand Colonies
abroad, I do hereby declare this to be my Specification of the same, and that I
do verily believe this mysaid Specification doth comply inall respects, fullyand
without reserve or disguise, with the proviso in the said herein-before in part
recited Letters Patent contained. Wherefore I do hereby claim to maintain

page_text: exclusive right and privilege to my said several Inventions ofimprovements in
the steam engine.
In witness whereof, I, the said James Pilbrow, have hereuntoset my hand
and seal, this Twenty-third day of November, One thousand eight
hundred and forty-two.