CERTAIN NEW IMPROVE- MENTS UPON STEAM OR FIRE ENGINES FOR RAISING WATER, AND OTHER MECHANICAL PURPOSES, AND CERTAIN NEW PIECES OF MECHANISM APPLICABLE TO THE SAME
Year: 1782

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JANES
Warr, of Birmingham, in the County of Warwick, Engineer, senil greeting.
WHEREAS His most Excellent Majesty King George the Think, by Ilis
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twelfth day of March, in the twenty-second year of His reign,
did give and grant unto me, the said James Watt, His especial licence, full
power, sole privilege and authority, that I, the said James Watt, my exors,
adñiors, and assigns, should and lawfully might, during the term of years
therein expressed, make, use, exercise, and vend, within that part of His
Majesty's Kingdom of Great Britain called England, His Dominion of Wales,
and Town of Berwick-upon-Tweed, my Invention of "CERTAIN NEW IMPROVE-
MENTS UPON STEAM OR FIRE ENGINES FOR RAISING WATER, AND OTHER MECHANICAL
PURPOSES, AND CERTAIN NEW PIECES OF MECHANISM APPLICABLE TO THE SAME;" in
which said recited Letters Patent is contained a proviso obliging me, the said
James Watt, by an instrument in writing under my hand and seal, to cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, to be inrolled in His Majesty's High Court of
Chancery within four calendar months after the date of the said Letters
Patent, as in and by the said Letters Patent, relation being thereunto had,
may more at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso. I, the said
James Watt, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, is described and ascertained in
manner and form following, that is to say :-
My said new inquvements on steam or fire engines, and my said new
pieces of mechanism applicable thereto, are described as followeth; but to
prevent misunderstandings and circumlocutions or tautology, I shall first
explain the meaning of certain terms which are used in this Specification.
First, the cylinder or steam vessel is that vessel wherein the powers of steam
or air are employed to work the engine, of whatever form it may be made,
though it is most commonly made cylindrical. Second, the piston is a move-
able diaphragm, sliding up and down or to and fro in the cylinder, and fitted
to it exactly, on which piston the powers of steam or air are inmediately
exerted. Third, the condensers are certain vessels of my Invention, in which
the steam is condensed, either by immediate mixture with water sufliciently
cold or by contact with other cold bodies, which condensers are situate either
in that part of the cyller itself which the steam never enters except to be
condensed or reluced to water, or they communicate with the cylinder by
means of pipes which are opened or shut at proper times, or those pipes called
chuction pipes which leal to the air pumps or other countrivance for carrying
of the condensed steam, air, and water of injection, are themselves used for
that purpee. Fourth, the air and hot water pumps are pumps or other
contrivances which serve to extract the air and heated water from the
linders and condensers. Fifth, the working beam is a double-ended lever,
a wheel or wheels, or other machinery, establishing the means of communi-
cating the power from the piston to the pump work or other machinery to be
wrought by the engine.
My first new improvement in steam or fire engines consists in admitting
steam into the cylinders or steam vessels of the engine only during some certain
part or portion of the descent or ascent of the piston of the said cylinder, and
using the elastic forces, wherewith the said steam expands itself in proceeding
to occupy larger spaces, as the acting powers on the piston through the other
parts or portions of the length of the stroke of the said piston, and in applying
combinations of levers or other contrivances to cause the mequal powers
wherewith the steam acts upon the piston to produce uniform effects in working
the pumps or other machinery required to be wrought by the said engine,
whereby certain large proportions of the steam hitherto found necessary to do
the same work are saved; to explain which principal or improvement I have
delineated a section of a hollow cylinder at Figure 1st in the annexed Draw-

page_text: ing. The said cylinder is perfectly shut at the lower end by its bottom C, D.
and also at the upper end by its cover A, B; the solid piston E, F, is accurately
fitted to the said cylinder, so that it may slide easily up and down, yet suffer
no steam to pass by it. The said piston is suspended by a rod (or rods) G, II,
which is capable of sliding through a hole in the cover (A, B,) of the cylinder,
and its circumference is made air and steam tight by a collar of oakum or
other
proper materials well greased, and contained in the box 0; and near the
top of the cylinder there is an opening J, to admit steam from a boiler. The
whole cylinder, or as much of it as possible, is inclosed in a case M, M, con-
taining steam, or otherwise is maintained of the same heat with boiling water,
or of the steam from the boiler. Those things being thus situated, and the
piston placed as near as may be to the top of the cylinder, let the space of the
cylinder under the piston be supposed to be exhausted or emptied of air,
steam, and other fluids, and let there be a free passage above the piston
for the entry of steam from the boiler, and suppose that steam to be of the
same density or clastic force as the atmosphere, or able to support a column of
mercury of thirty inches high in the barometer. Then I say that the pressure
or elastic power of the said steam on every square inch of the area or upper
side of the piston will be nearly fourteen pounds averdupois weight, and that if
the said power were employed to act upon the piston through the whole length
of its stroke, and to work a pump or pumps either immediately by the piston
rod prolonged, or through the medium of a working beam or great lever, as
is usual in steam engines, it would raise through the whole length of its stroke
a column or columns of water whose weight should be equal to ten pounds for
each square inch of the area of the piston, besides overcoming all the frictions
and vis inertiea of the water, and the parts of the machine or engine. But sup-
posing the whole distance from the under side of the piston to the bottom of the
cylinder to be eight feet, and the passage which admitted the steam from the
boiler to be perfectly shut when the piston has descended to the point K, two fret
or one-fourth of the length of the stroke or motion of the said piston, I say that
when the piston has descended four feet or one-half of the length of the stroke,
the elastic power of the steam would then be equal to seven pounds on cach
square inch of the area of the piston, or one-half of the original power; and that
when the piston had arrived at the point P, the power of the steam would be
one-third of the original power, or four pounds and two-thirds of a pound on
each square inch of the piston's area, and that when the piston had arrived at
the bottom or end of its stroke, that the elastic power of the steam would be
one-fourth of its original power, or three pounds and one-half pound on each
square inch of the said area. And I further say that the elastic power of the

page_text: steam at the other divisions, marked in the lengths of the said cylinder, are
represented by the lengths of the horizontal lines or ordinates of the curve
K, L, also marked or delineated in the said cylinder, and are expressed in
decimal fractions of the whole original power the numbers written opposite
to the said ordinates or horizontal lines; and I also say, that the sum of all these
powers is greater than fifty-seven hundred parts of the original power, mul-
tiplied by the length of the cylinder, whereby it appears that only one-fourth
of the steam necessary to fill the whole cylinder is employed, and that the
effect produced is equal to more than one-half of the effect which would have
been produced by one whole cylinder full of steam, if it had been admitted to
enter freely above the piston during the whole length of its descent; conse-
quently that the said new or expansive engine is capable of easily raising columns
of water, whose weights are equal to five pounds on every square inch of the
area of its piston, and that with one-fourth of the contents of the cylinder of
steam; and be it remembered, though for example's sake I have mentioned
the admission of one-fourth of the cylinders full of steam (as being the most
convenient), that any other proportion of the fill of a cylinder, or any other
dimensions of the cylinder, will produce similar effects, and that in practice I
actually do vary these proportions as the case requires; and also in some cases
I admit the required quantity of steam to enter below the piston, and I pull
the piston upwards by some external power against the elastic force of the
steam from the boiler, which then always freely communicates with the upper
part of the cylinder, and which produces similar effects to those described;
but the powers which the steam exerts being unequal, and the weight of the
water to be raised or other work to be done by the engines being supposed to
resist equally throughout the length of the stroke, it is necessary to render the
whole acting powers equal by other means. I perform this, first, by means of
two wheels or sectors of circles, one which is attached to the pump rods, and
the other to the piston rod of the engine, and which are connected together
by means of rods or chains or otherwise, so that the levers whereby they act
upon one another decrease and increase respectively during the ascent or
descent of the piston, in or nearly in the ratios required.
This method, mechanism, or contrivance is delineated in Fig. 2d, and also its
application to one of my new invented steam engines, the sole use and benefit
of which was granted to me by an Act of Parliament, passed in the fifteenth
year of the reign of His present Majesty.
The operation of the engine with this new mechanism added to it is
described as follows:-The piston A being at its highest place, and the part of
the cylinder under it exhausted of steam and air, the regulating valve which

page_text: admits the steam to enter below the piston being shut, and the valve F which
allows steam or air to pass to the condenser (G, K.) being open, in order to
maintain a good vacuum, the top regulating valve D is opened, and permits
the steam from the boiler to enter and act upon the piston, which then begins
to descend and to pull round the wheel or sector of a circle to which it is hung.
When the point Q of that wheel has moved to I, the piston has descended
two feet, and V of the wheel to which the pump rods or other machinery
wrought by the engine are suspended, being pulled by the red (5) connecting
it with the other wheel Q, R, S, T, U), will have moved through the space
V, W, the regulating valve D is then shut, so that no more steam may be
admitted from the boiler during that stroke, but the piston continues to descend
by virtue of the expansion of the steam, and when the point Q is come to
the points R, S, T, U, the point V is come to the points W, X, Y, Z,
respectively, describing spaces which are nearly proportional to the powers
of the steam at the corresponding points of the descent of the piston. When
the piston has made its stroke and is come to the bottom of the cylinder, the
regulating valve F is shut, and the valve E is opened, by which means the
steam passes from the part of the cylinder above the piston to the part below it
by the pipe C, and so restoring the equilibrium, permits the piston to ascend to
its position. The regulating valve E is then to be shut, and the exhaustion
regulating valve F is opened; the steam rushes into the eduction pipe G, G
where it meets a jet of cold water which enters through the injection pipe II,
which is opened immediately before the regulating valve F. The contact of
this cold water immediately reduces the steam to water, and produces a vacuum
under the piston, and thereby enables the elastic force of the steam to act again
upon it, as has been described; or instead of injecting cold water into the con-
denser or eduction pipe itself, I bring the steam into contact with thin plates
or pipes of metal which have their external surface cooled by contact with
water or other cold matter. The condensed steam, the injection water, and the
air which entered with it or any other air which has entered by other means,
proceed by the eduction pipe to the air pump K, and passing the valves of
its bucket or piston are retained and lifted up by it on the return of the
stroke, and thereby are thrown into the hot water pump J, which by the
next stroke raises up and delivers them into the atmosphere, from whence
part is returned into the boiler to supply its consumption of water, and
the remainder is conveyed away for any other purpose, or runs to waste.
Another variety of this method of equalizing the power is delineated in
Figure 3d. The piston is suspended to the arch A by means of a chain or
otherwise, and the pump rod is suspended to the arch B. The primary or

page_text: cylinder arch A by means of the arm O, P, and the rod or chain O, C, acts upon
the working beam B. C, to the arch of which the pump rods are suspended, by
which means, while the piston descends through the equal spaces J K, KL,
1. M, M N, the pump rod is made to ascend through the unequal spaces
DEEF, FG, GII, which are nearly proportioned to the elastic forces of the
steam at the respective points. My second method or piece of mechanism for
equalizing the powers of the steam is by means of chains, which are wound upon
one spiral and wound off another as the piston descends, which spirals are fixed
apon two wheels or sectors of circles to which the chains of the piston and pump
rods are attached, and is represented in Figure 4th. The piston is suspended
from the side A of the wheel A, B, and the pump rods from the side C of the
wheel D, C, which wheel D, C, being pulled by the chains J, R, K, the points
of its circumference move through the unequal spaces K L, L, M, M N,
NO, (almost exactly proportioned to the powers of the steam.) while the
points of the circumference of A, B, move through the equal spaces E F,
FG, GH, HI. My third method or piece of mechanism for equalizing
the powers of the steam is by means of a friction wheel or wheels attached to
or suspended from one sector or wheel, and acting upon a curved or straight
part of another sector wheel or working beam. Two modes of this contrivance
are delineated in Figs. 5th and 6th, of which it is only necessary to observe
that the pistons of the engines are suspended to the arches A, A, and the pump
rods to the arches of the working beams D, B, and that these contrivances
afford the means of equalizing the powers of the steam very exactly. My fourth
methoil or piece of mechanism for equalizing the power of the steam is by
causing the centre of suspension of the working beam or great lever to change
its place during the time of the stroke, whereby the end of the lever to which
the piston is suspended becomes longer, and the end to which the pump rods
are suspended becomes shorter, as the piston descends in the cylinder. An easy
method of doing this is represented in Fig. 7. A, B, represents the working
heam; B, the end to which the piston is suspended; A, the end to which the
pump rods are suspendled; C, D, a hollow curve of wood or metal fixed to the
lower side of the working beam; E, the end of a friction roller, which rolls
between the enrve C, D, and the plane or support F, G. This friction roller
is divided into three parts, as may be seen in its horizontal view K, L, M; the
two end parts K, M, which roll upon the supports F, G, are fixed firmly upon
an axis; the middle part L, which rolls under the curve C, D, can turn round
on its axis, therefore when by the action of the piston on the working beam the
end B is pulled downwards, the roller proceeds towards C, to the part of the curve
which is then the highest, and thereby lengthens the lever by which the piston

page_text: acts on the pumps, and shortens that by which the pumps resist the cylinder,
and that in any ratios which may he required, according to the form of the curve.
My fifth method, piece of mechanism, or contrivance for equalizing the power
of the steam consists in placing upon, suspending from, or fixing to the working
beam of the steam engine or some other beam, wheel, or lever connected with
it, a quantity of heavy matter in such a manner that the said heavy matter
shall act against the power of the piston at the commencement of the descent of
the said piston, and as the piston descends shall gradually move towards that end
of the beam to which the piston is suspended, or otherwise shall act in favour
of the piston in the latter part of the stroke. Three methods or varieties
upon this principle are represented at Figs. 8, 9, and 10. Fig. 8 operates by
means of a heavy cylinder A, of iron or other material, which rolls in a hollow
curve B, C, on the back of the working ham, and will consequently change
its place and proceed towards the cylinder end of the beam as the piston
descends. In Fig. 9th, the same is performed by a heavy weight of iron or
other matter A, fixed above the beran or wheel, so that its centre of gravity
at beginning the motion lies nearer the pamp end of the beam than the
centre of suspension of the beam, whereby it acts against the piston, and at
last comes to be at the same side of that centre with the end to which the
piston is suspended, and thereby acts in its favour. Figure 10th shows a
mothed of fixing the working beam itself en as to perform in some degree the
office of the weight in Figure 0th. Fig. 11th shows a fourth method whereby
I perform the same thing, by causing a quantity of water or other liquid to
oppose the ascent of the piston in the beginning of the stroke, and to assist it
in the latter part. A and B represent two eylinders or other formed vessels,
filled with water or some other liquid above their pistons C and D, the reds
of which are fixed (or suspended) to the working beam of the engine, or such
secondary or auxiliary beam as may be applied to this ase, on the opposite
sides of its axis. These cylinders are open at bottom and at top, and at the
top part they are connected together by a lauder or trough, close or open; when
the piston descends it raises the opposite end of the working beam and the
piston of cylinder B, and thereby causes the water it contains to run over
into A, the piston C of which becoming loaded thereby in proportion as
piston D rises, gradually comes to assist the piston of the steam vessel in the
latter part of its motion. These cylinders, containing water, be either placed
below the working beam or above it, or may be suspended to a secondary
working bean constructed for that purpose or necessary for some other use,
comceted with the piston rod or pump rod or other part, and placed so that
the water cylinders may be out of the engine-house in some place where it

page_text: may be found to be more convenient. My sixth method, piece of mechanism,
or contrivance for equalizing the powers of the steam consists in employing
the surplus power of the steam upon the piston in the first parts of its motion,
to give a proper rotative or vibratory velocity to a quantity of matter, which
retaining that velocity shall act along with the piston and assist it in raising
the columns of water in the latter part of its motion when the powers of the
steam are defective. Two methods by which I perform this are delineated in
the Drawing of the engine, Fig. 12th. The heavy fly X, X, is put in motion
by means of a pinion or smaller wheel Y, fixed upon its axis, and the teeth of
which pinion or smaller wheel are acted upon by the toothed sector Q Q
fixed upon the arch of the working beam, or the said fly is by other means
connected with the motion of the said working beam. When the piston
pulls down the end of the working beam, the toothed sector Q. Q. gives
motion to the pinion, and thereby gives velocity to the fly, and when the
descending or ascending velocity of the arch or sector of the working beam
comes to be less than the velocity which the pinion and fly have acquired,
then the velocity of the fly continuing, causes the pinion to act upon the sector
in its turn, and assist the powers of the steam, until its velocity is spent, or the
piston has reached the bottom of the cylinder; and the said fly operates in
like manner during the ascent of the piston, but turns then in the contrary
direction. In the second variety of this method, a fly or heavy wheel is put
into a continued rotative motion by a crank, by any of the rotative motions for
which I have obtained His Majesty's Royal Letters Patent, dated in the
present year of His reign, or by any other means which shall or can produce
a continued rotative motion. And the said rotative machinery is connected
with or joined to either end of the working beam, to or with the piston rod
itself, to or with the pump rods, or to or with any other moving part of the
engine or pump rods which is found proper.
In the Drawing, Figure 12th, T, U, W, V, V, represent the application of my
fifth method of producing rotative motion from steam engines, as a method or
contrivance for equalizing the power of the steam. The piston being at the
top of the cylinder, and the working beam in the situation delineated, the
engine begins its strokes, and by means of the connecting rod T, T. pulls
upwards the toothed wheel W, which is fix't to the connecting rod in such
manner that it cannot turn upon its own axis, and is confined by means of a
link or chain reaching from its centre to the axis of the other toothed wheel U,
or is otherwise so contrived that it cannot recede from it; therefore, when the
action of the engine pulls the wheel W upwards it revolves round the other
wheel U, and causes it (U) to revolve upon its own axis, and the fly or heavy

page_text: wheel V, V, being fixed upon the same axis, it is also put into motion, and
because of the great power of the steam in the first parts of the stroke, the fly
acquires a great velocity, whereby through the medium of the two wheels and
the connecting rod, it acts upon the working beam, and assists the action of
the steam in the latter parts of the stroke. When the piston has compleated its
stroke downwards, the lower edge of the wheel W has passed over the upper
edge or highest part of the wheel U, and the velocity of the fly continuing,
the wheel U acts upon the wheel W, and assists the unbalanced weight of the
pump rods in raising the piston to the top of the cylinder. But be it remem-
hered, that I, (the said James Watt,) do not mean that anything which I have
herein set forth touching or concerning this second variety of applying my
sixth method or contrivance for equalizing the powers of the steam, shall be
construed or thought to be intended to preclude any other person or persons
from using or applying to the moving, turning, or working of mill-work or
other machinery where continued rotative motions are required, any con-
trivances or inventions for producing rotative motions from steam engines,
provided that such rotative motions or machinery be not of my invention, and
such engines be not applied principally or solely to the raising of water, the
true intent and meaning of the aforesaid last article of this writing being to
specify the means by which I apply continued rotative motions, as some of
my methods or contrivances to equalize the expansive powers of the steam in
engines, which are principally or wholly for the raising of water from mines,
rivers, ponds, marshes, lakes, and other places.
My second improvement upon steam or fire engines consists in employing
the elastic power of the steam to force the piston upwards, and also to press
it downwards alternately, by making a vacuum above or below the piston
respectively, and at the same time employing the steam to act upon the piston
in that end, or exerted upon the piston only in one direction, whether upwards
or downwards.
This improvement, as applied to one of the steam engines of my Invention,
is delineated in Fig. 12th. The lower part of the cylinder B being exhausted
of air, steam, and other fluids, the regulating valve F, being open, and the
regulating valves E and N being shut, the regulating valve D is opened, which
admits the steam from the boiler to press upon the upper side of the piston, by
the action of which steam the piston descends, pulls down the cylinder end of
the working beam, and raises the end to which the pump rods are suspended.
When the piston is arrived at the bottom of the cylinder or end of its stroke,
the valve F is shut, and the valve E is opened, which admits the steam under

page_text: the piston, and at the same time the valve D is shut, which prevents the steam
from coming from the boiler into that end of the cylinder, and the other valve
N in the upper nozle or regulator box is opened, which permits the steam
to rush from above the piston into the sduction pipe G, G, where it meets
the jet of injection water, which condenses it and produces a vacuum in the
upper part of the cylinder, which, destroying the equilibrium, permits the steam
under the piston to force it upwards. Then the piston rod, being fast in the
piston, and having the toothed rack 0, 0, fixed to its upper end by means of
the teeth thereof, which are engaged in the teeth of the toothed sector, which
is fixed to or forms a part of the arch Q. Q. of the working beam, or by means
of double chains or any other practicable method, the piston or its rod raises
the cylinder end of the working beam, and also a heavy weight concealed or
contained in the arch thereof, or otherwise fixed, attached, or susperuled thereto,
which weight ought to be equal or nearly so to the force or power of the steam
when acting upon the piston in the ascending direction. When the piston is
arrived at the summit of its motion, the regulating valves E and N are to be
shut, and the regulating valves D and F opened, whereby the piston again
commences its motion downwards, as has been described, and during the
descent of the piston, the weight Q, Q, fixed or suspended to the working beam,
assists the power of the steam on the piston in raising the column of water in
the pumps, or in working other machinery.
In Fig. 13 is delineated a front view of the cylinder, and a section of the
condenser of this engine, wherein the pipes which convey the steam from the
boiler and to the condenser are properly distinguished and explained.
This improvement permits the engine to be usel either with the uniform
exertion of the whole power of the steam on the piston, both in the descent
and ascent, or by making the weight of the columns of waters in the pumps,
or the resistance of other machinery which it may be required to work equal
to the full power of the steam upon the piston when acting in one direction
only, and the weight on the working beam equal to half that power, it may
be used as a double expansive engine, and wrought in the manner I have
herein set forth in the description of my first improvement. And in such
case, the fourth, fifth, and sixth contrivances herein described for equalizing
the powers of steam, are peculiarly applicable to this mode of constructing
the engine.
Wherefore I have delineated the two varieties which I have
described of the sixth method, as applied to this engine; and be it remem-
bered, that either or both of them may be used at the same time, though only
one is strictly necessary, and that any other two or more of the aforesaid six

page_text: contrivances, or of the varieties thereof, may be applied to one engine at
the same time, that is to say, such of them whose nature admits of such
combination.
My third improvements on steam or fire engines consists in connecting
together by pipes, or other proper channels of communication, the steam
vessels and condensers of two or more distinct steam engines, each of which
has its seperate working beam and other constituent parts of a steam engine,
or is otherwise so constructed that it can work pumps or other machinery,
which are either connected with or are independant of those wrought by the
other engines, and which two engines can take their strokes alternately or both
together, as may be required. The construction of the said machine is described
as followeth, and an external front view of the steami vessels or cylinders and
condenser of the two engines is delineated at Fig. 14th of the Drawing hereunto
annexed; the section or side view of the two engines is not delineated, because
when viewed in that direction, only one of them can be seen, the other being
hid hy it, and the engine which could be seen would appear the same as the
engine delineated in Fig. 2d, or in respect to the working beans as the engine
delineated at Figure 12th; these compound or double engines admitting the
application of any of the equalizing machinery which has been herein-before
described. In Fig. 14th the cylinder of the primary engine No. 1, receives
steam from the boiler by the steam pipe (8, 9), which steam enters the cylinder
by a regulating valve situated at D, its piston being at the upper ends of its
stroke, and the part of the cylinder which is below the piston being exhausted,
the elastic power of the steamx presses down the piston until it arrives at the
bottom or termination of its stroke, the regulating valve D is then shut, and
the middle regulating valve at E is opened, which admits the steam to enter
under the piston, whereby the engine is enabled to raise up the piston to the
top of its stroke where it was at the beginning, the middle regulating valve E,
is then shut, and the regulating valves F and Pare opened, the valve F permits
the steam to pass through the eduction pipe N into the perpendicular steam
pipe R of the sceondary engine, and to press upon its piston, under which
piston there is a vacuum. The steam which is or was contained under the
piston of the primary engine No. 1, being of the same density with the
atmosphere or nearly so, will, while the piston of the secondary engine (No. 2)
remains stationary, act upon it with the full power belonging to its density
or elasticity, and will thereby cause to it commence its motion downwards,
but as the piston of (No. 2) moves downwards, the density and elastic force
of the steam will diminish in proportion as the spaces which it occupies aro

page_text: increased, so that in case the cylinders of the two engines are of an equal
capacity, when the piston of No. 2 has arrived at the bottom or lower
ond of its stroke, the density and elastic force of the steam will be only
One-half of what they were while the piston remained at the top; therefore
if a simple lever, wheel, or working beam is used for this secondary engine
(No. 2), the engine ought only to be loaded with a column of water or other
work, equal to half the number of pounds on each square inch which the
primary engine No. 1 is able to work with. But if the secondary engine No. S
is furnished with any proper contrivance for equalizing the powers of the steam,
St may, in case the cylinders of the two engines are of equal capacity, be made
to do soven-tenths of the work which is done by the primary engine (No. 1).
When the piston of the secondary engine (No. 2) has come to the bottom of
its stroke, the middle regulating valve O is opened, and the steam rushes into
the condenser G, K, and in its way meets the jet of injection water, which
condenses it, and thereby the upper part of the cylinder of the secondary
engine and the lower part of the cylinder of the primary engine are exhausted
of steam. The piston of the secondary engine (No. 2) having then a vacuum
both above it and below it, is pulled up easily by the working beson of that
engine, and there being a vacuum under the piston of the primary engine
(No. 1) the steam from the boiler exerts its power upon it and presses it
down, and the other motions are repeated, as has been described.
These compound engines may also be wrought in other manners, of which I
shall describe one of the best :-Let the eduction pipe N be supposed to be
removed, and a steam pipe S (which is delineated in red ink) he made to com-
municate between the perpendicular steam pipe C of the primary engine and
the top regulator box or cross pipe Q of the secondary engine, then the piston
of the primary engine (No. 1) being pressed to the bottom by steam, shuts its
top regulating valve D, and opens the top regulating valve Q of the secondary
engine, the piston of that engine will immediately begin to deseend with a
decreasing power (as has been remarked before); when the piston of the
secondary engine No. 2 has come to the bottom of its stroke its middle regu-
lator O is opened, whereby the steam rushes out of the cylinders of both the
engines into the condenser or condensers, and there being vacuum both above
and below the pistons of both engines, the equilibrium of both is restored, and
both the pistons are permitted to be raised by the unbalanced weight of the
pump rods or other weights or machinery applied for that purpose. It is
proper in this mode of application to make a small pipe leading from the lower
part of the cylinder of the primary engine to the eluction pipe or condenser

page_text: of the secondary engine, whereby the vacuum under and above both pistons
may be maintained of an equal degree of rareness or perfection.
For the more clear understanding of these improvements and contrivances,
I have delineated them on the parchments hereunto annexed, according to
the schales specified on the respective Drawings, and have adapted them all,
except Fig. 1st, to engines whose cylinders are thirty inches in diameter, and
the length of the stroke of whose pistons is eight feet; but I make the cylinders
larger or lesser, longer or shorter, and vary the proportions and shape of them,
and of the other parts, according as their uses may require; and as each
improvement, method, piece of mechanism, or contrivance admits of numberless
variations, I have set forth and delineated only such as I esteem to be among
the best, and which are the most casy to be executed.
My fourth new improvement on steam or fire engines consists in applying a
certain mechanical contrivance called a toothed rack and sector of a circle, or
toothed racks and toothed sectors of circles, for suspending or connecting the
pump rods or pistons with the working beams, levers, or other machinery
used in place of them, in place or instead of chains, which have hitherto been
used for these purposes. This new improvement or mechanical contrivance is
delineated at 0, Q, Fig. 12th, and requires no other explanation than to say
that it is delineated by a schale of one-fourth of an inch to each foot of the
real size, according to its proper dimensions for a cylinder thirty inches in
diameter; and the said rack and sector are supposed to be made of hammered
or cast iron, but it may be made of wood or other materials by giving it dimen-
sions suitable to the strength of the material of which it is made; and in order
to accommodate the same to cylinders of other sizes, the strength of its parts
must be increased or diminished in proportion to the powers of the respective
cylinders to which it may be applied. I have described and delineated all my
aforesaid new improvements upon and new mechanical contrivances appli-
cable to steam engines as applied to or connected with the new steam
engines of my own invention as being the most perfect hitherto made;
but it must be remembered that I do apply the same to the common.
steam engines known by the name of Newcomen's steam or fire engines, and
that they are also applicable to any other species or variety of steam engines
which works with a piston moving in a cylinder or steam vessel, and
that they will in such engines produce greater or lesser effects in proportion
to the degree of perfection of the engine to which they are applied.
It is also to be remarked that though I have described all the engines
standing erect and having the piston rods coming through holes in the top of

page_text: the cylinder, that the same or nearly the same effects will be produced though
the piston rods come through holes in the bottom of the cylinder, and the
working beams or equalizing machinery be placed under them, or although the
cylinders and working beans are placed inclined or horizontally, and that in
certain cases I use them in such different positions.
My fifth new improvement on steam or fire engines consists in making the
steam vessels in the form of hollow cylinders, or in the form of other regular
round hollow vessels, or in the form of greater or lesser segments or sectors of
such bodies or vessels, and I place in the centre or axis of the circular curvature
of such vessels a round shaft or axle passing through and extending beyond
one or both ends of such steam vessel; and I shut up the ends of the said
steam vessel with smooth plates, which have proper appertures for the said
axle or shaft to pass through; and within the said steam vessel 1 fix to
the said axle a piston or plate extending from the said axle to the circular
circumference of the steam vessel, and also extending from one end of the
stean vessel to the other; and I make the said piston steam-tight by sur-
rounding the parts which fit to the steam vessel with hemp or other soft
substances, soaked in grease, oil, or wax, or by means of springs made of
steel or other solid and elastic or pliable materials; and to the said steam vessel
I fix one or more plates or divisions, extending from the axle to the circum-
ference of the steam vessel, and where these plates or divisions join to or approach
the axle, or where the said axis passes through the end plates of the steam
vessel, I make such joining steam and air tight by the means above recited.
In the steam vessel, on each side of the said piston, I make one or more
channels or appertures for receiving and discharging the steam, which chan-
nels I furnish with proper valves for that purpose. I also apply to the said
engine proper condensers and air pumps; and the pumps which raise water,
or such other machinery as is required to be wrought by the said engine, are
put in motion or worked by a wheel or wheels fixed to or upon the external
parts of the said axle, or by any other mechanism which may be suitable, and
the said engine so constructed is wrought by admitting the steam between the
fixed division and the moveable piston, and exhausting or making a vacuum
on the other side of the said piston, which accordingly, by the force of the
steam, moves into the said vacuum and turns the axle or greater or lesser
portion of a circle, according to the structure of the machine. The piston is
returned to its former situation by admitting steam on the other side of the
said piston, and drawing the piston back by some external power, or by
exhausting the part of the steam vessel which was first filled with steam.

page_text: An engine constructed upon this principle is delineated at Figures 15th,
16th, and 17th, in the annexed Drawing, according to a schale of one-fourth
of an inch to each foot of the real size; but I make them greater or lesser,
and vary the shape and size of the steami vessel and other parts according to
their use. The operation of the engine is as follows:-The steam vessel
A, A, A, being exhausted of steam and air, and the regulating valves K
and I being shut, and I and II open, the steant coming from the boiler
through the pipe M, enters the steam vessel by L and G, and causes the
piston C to turn round into or towards the exhausted part of the steam
vessel A, X, and thereby turns the axle D and the machinery attached to it
until the piston C comes to X; the regulating valves I and H are then shut,
and K and J are opened; the steam which had entered by the pipe G, and had
acted upon the piston, returns through G and J into the condenser or eduction
pipe 0, where it is condensed, and the steam from the boiler, entering through
K and F, forces the piston C to return to its first situation. The pump
rods U, W, or other machinery, are wrought by the wheel S. 5, fixed on the
axle D, B, or otherwise, see Figs. 16th and 17th, and the condenser pump (or
pamps) is wrought by the wheel 2, fixed to any part of the said axle or other-
wise. It is to be understood that the said steam vessel is to be firmly fixed so
that it cannot move, and that the gudgeous or pivots of the said axle must be
rosted upon proper supports, which things could not be exhibited in the
Drawing without confusion. I also cause engines made according to this fifth
improvement to revolve with a continued rotative motion, by making their
steam vessels compleat cylinders or other circular figures, and in place of the
fixed division or divisions, I place one or more valves in their steam vessels,
which shut or close the area between their axles and their circumferences,
and which valves open by turning upon a hinge or joint, or are drawn back by
a sliding motion like a drawer, or otherwise are constructed so that they may
be removed when the piston comes to them, and thereby suffer it to pass by
the place where they were (see the Drawing, Figure 18th), and so begin a
new revolution in the same direction; or I make a fixed division or divisions,
as has been described, and I fix one or more valves to the axle, which valvos
are capable of folding down and of applying themselves to the axle and of
forming a part of its circumference, so that they can thereby pass by the
division, and when they have passed it they are raised up by springs or otherwise,
so as to perform the office of a piston or pistons. I have not described the
boilers which supply any or all of these engines with steam, because I uso such
as are commonly applied to other steam engines, or any kind of boiler which is

page_text: capable of producing steam in sufficient quantities; neither have I described
the machinery which opens and shuts the regulating valves, as it is similar to
that which is in common use, and may be varied at pleasure.
In witness whereof, I have hereunto set my hand and seal, this Third
day of July, in the year of our Lord One thousand seven hundred and 5
eighty-two.
in the presence of
JOHN SOUTHERN.
PETER CAPPER.
AND BE IT REMEMBERED, that on the Third day of July, in the year
of our Lord 1782, the aforesaid James Watt came before our said Lord the
King in His Chancery, and acknowledged the Specification aforesaid, and all
and every thing therein contained and specified, in form above written. And
also the Specification aforesaid was stampt according to the tenor of the
Statutes made in the sixth year of the reign of the late King and Queen
Wand Mary of England, and so forth, and in the seventeenth year of the
reign of His Majesty King George the Third.
Inrolled the Fourth day of July, in the year of our Lord One thousand
seven hundred and eighty-two.

page_text: which args the Steam from the upper to the under end of the Steam Tessel
The place of the Top regulating Vatre E The place of the Middle regulating
lab F The place of the Exhaustion regulating Vabe 6.6 The Eduction Pipe
Hi The Injection Pyx 1The Hotwater Pump The Air Pump LA Fatre at the
Education Pipe foot to prevent the regress the Water M.The Passage to the
fromter Puny N The Plug tax by the motion which the regulating Vabres
an opened and shut C. One of the Posts which gude the Plugtree. P. The liston
Bod QRSTU The Wheel te wach the Proton Rod is suspended TWXYZ. The
Wheel to much the Pump Rods are hung 1. The Condenser Pump Rods 2.4 hear
Platform, to which the Cylinder is fastened & The Spring Beams 44 The Springs
5. The Rod which connects the twe Wheels which form the Working Beam:
The Pump Rods

page_text: A Cross Section of a spindle which comes
through the ade of the bar and mores
the Amor Sector B which acts on the
Rack with raises the Regulating Faire
D which is grand to fit the Seats EE and
is gouded by the Sake FF GG. The Pipe
which leads to the Condenser Katever which
is quened occasionally to rectify the labe
par & the Nesle
H
Fall The fourth Variety of the fifth Species of the New Equalising Machinery AABB Tw Cylinders antais
water and connected by the Though (FF) Thar Pistons CD are supposed to be suspended from the quesite ne
fa Working Beam whose centre of motion or badgan is supported upon the Wall EE, and which Beam is
so connected with the Proton or the Engine that when the soud Piston descends it rasses the Piston of the
water Cylinder which is then lowest and thereby causes the water which it contains to pass by the trough
the other water Glinder, and by its granty, to assist the descent of ye Proton of the Engine

page_text: Fig 12 Represents the New Improved Engine the Piston of which is pressed
forcibly both Upwards and. Demmurds in the Powers of Steam.
A The Piston BB The Ginder a Steam level CAPipe which brings Steam from
the Baler to the lower Regulator Box or Nozle D The place of a Regulating kabe
which admits Steam into the upper and of the Steam Vessel E. The place of the
Regulater which admits Steam below the Proton F The place of a Regulater
which lets Steam go out from below the stem into the Condenser N Place of
a Regulator which discharges the Steam from above the Psim. GG The Educa
a Condenser Pipe. H The Injectum Pye The Heater Pump K The Air Hump.
1. Vatre at the Extuction Pips feet M. A Passage from the Air Pump to the
Hotwater Pump COA Toothed Rack which connects the Piston Rod and the
Working Beam, P The Proton Rod 00. A toothed Sector or Arch which also
serves for a Weight to assist the Piston in its descent QK The Working Beam
SS. The l'ump Rod, which is made double when the Retative Muchinery is used
J
The connecting Rod of the Rotative Machinery The Wheel fixed upon an
Acis W The Whed fixed to the connecting Rod VV The Fly II The Pty of the
Reaprocating Rotator motion. I The Pinum by means of which it ac is aded
on in the Working Beam. 9 The Pipe which brings Steam from the Boiler

page_text: Regresents a Frend Vor of theber tempend or Disbelagine
us men hemm the Low Wall
1 The Nem lessed and some other parts of the Primary Engine
3. The meal, and her part the Secondary Engine.
Bache Tip regoisting Fabre
The Perpendinier kam
30 Pas de Middle Boats PPM
Relates & Bauction PKL and Pap
from the Air Pump to the P&D communicating
the Seam from the Primary Engine & the Secondary Engine instend
of the Educhen N. 6.9.1pes which cover the Steam tree, the
Boiler These Engines may have war, ar the sme
Condenser may serve both, as to here delineated.
The Sule for the Engines wall the same g
12 sarding to the Construxander Working Beams. The
Better Png is beken this braming and interfering

page_text: &ler Quinde
EE the Steam and
in the Bolo NN The Steam
hele of Axis
Reater Box
6p
AGA. Ron
the tingue at right angles to the ache or yingine under
The Down Daber filled with me soft substance to make the joining of the derin Plates.
which admit and discharge the Steam L. Pates & Vans & Replates the
The Cantone The lure PP Gary Bus
gdf the Engine where the same lettes art pinced, on the same jurts in Pyle and take are Seckers was the Arte a tut
and the Wheel which ade yen the pumped? The What works the finden. Pr 17 Outole Print Yas of the and p
The onder and Regular are are my drum in this with up the pump to speed when the th
ETWY The Prats and thus Rarks
the Amm enters of the tym ty and ade agams, the latre
Fand the morale Radius & Piston Caid the Space AA.
BB being exhausted, the Piston resolves thre
it by the
action of the Suum, and turns the Axle BB. Whay thudistim
comes to the be the pipe 6 is hat and the later Expens
permits the pisten to
into the Condenser by the
Vessel. When the Proton has
again shut and the Steam
by turning upon the pint D and
pass. The Steam then rushes
Pype 11 which exhausts the Steam
we to its riginal place. The abre
admitted through the Pipe 6 into the Jace between the bre
Band the Proton Cand te ontinue the motion during the
time that the Piston is passing the valve, & heary Fly is fizet
on, or connected with some part of the male Bon the outside
the Cylinder
The outside figure of the Pingine is nearly the same as lig
16 but the Steam set may be placed athe vertically as dram
or horizontally as its use may require.