CERTAIN IMPROVEMENTS IN ENGINES OR MACHINES FOR OBTAINING AND APPLYING MOTIVE POWER
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
NASMYTH, of Arundel Street, in the County of Middlesex, 'Gentleman, send
greeting."
WHEREAS Her present most Excellent Majesty Queen Victoria; by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Sixteeth day of February, in the ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Nasmyth, Her especial licence, full power, sole privilege
and authority, that I, the said James Nasmyth, my executors, administrators,
and assigns, and such others as I, the said James Nasmyth, my executors,
administrators, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein mentioned,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, and in all Her Majesty's
Colonies and Plantations abroad, and in the Islands of Jersey, Guernsey,
Alderney, Sark, and Man, my Invention of "CERTAIN IMPROVEMENTS IN ENGINES
OR MACHINES FOR OBTAINING AND APPLYING MOTIVE POWER;" in which said
Letters Patent is contained a proviso obliging me, the said James Nasmyth,"
by an instrument in writing under my hand and seal, particularly to
describe and ascertain the nature of my said Invention, and in what man-
ner the same is to be performed, and to cause the same to be inrolled in

page_text: Her 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 and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
James Nasmyth, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say):-
My Invention of Certain Improvements in Engines or Machines for
Obtaining and Applying Motive Power consists in the construction and working
of engines in a novel manner by the agency of steam, air, or other elastic
fluids, or other means whereby a greater amount of power is obtained than by
the means ordinarily employed. In my improved plan two, three, or more
cylinders may be employed as may be required, and the power of the motive
agent, whether it be steam, air, or gases, or any other pressure, is made to act
alternately, first at one end of the train. of cylinders and then at the opposite
end (that is to say), if there be two cylinders connected together by a tube,
the motive agent is admitted alternately above the piston and at the upper end
of each cylinder, each being in vacuo alternately. If more than two cylinders
are used, they are put in connection with each other by means of tubes, the
additional cylinders, whatever may be their number, are always in pleno (that
is to say), they are filled with air or some other elastic or non-elastic fluid,
the pistons of which cylinders move up and down simultaneously with the
pistons of the two end cylinders. The pistons of the two end cylinders, or those
which are alternately in vacuo, as before explained, are actuated alternately
by the introduction of the motive agent into the cylinders above the piston.
On the opposite side of the piston the space which intervenes between the
pistons of the two end or steam cylinders is occupied with air or any other
elastic or non-elastic fluid not susceptible of condensation. It will be under-
stood that the tubes which connect the cylinders together, as well as the
additional cylinders which are placed between the two end ones, are also kept
full of air or other elastic or non-elastic fluid not susceptible of condensation,
and therefore the power received by the piston of either of the two end
cylinders, which are alternately in vacuo, is simultaneously transmitted to any
other piston or pistons in any other cylinder or cylinders which may be
situated between the two end ones; and these additional cylinders may there-
fore be placed at any distance or in any position that may be required, always

page_text: provided that the communication is kept up by means of tubes, as will be
hereafter explained. Before proceeding, however, to a detailed description of
the engine, machinery, or apparatus, I will briefly recapitulate the principal
features of iny Invention, in order that the same may be clearly understood.
I connect two or more cylinders by a tube kept always full of air, gas, or any
other elastic or non-elastic fluid not susceptible of condensation. If there be
only two cylinders employed, and steam (high or low pressure) be the motive
agent used, a vacuum is formed in one of the two cylinders by the admission
and condensation of steam, as is done ordinarily in condensing engines. If
the vacuum is made above the piston in the one cylinder, steam is admitted
above the piston in the other cylinder; the space under this piston is full of
air, gas, or any other elastic or non-elastic fluid, and the tube which connects
the two cylinders being also full of the same matter which occupies the space
under the said cylinder. The valve in this tube being opened, the piston
will ascend in the one cylinder as it descends in the other cylinder, and the
power obtained will be two-fold with one jet or one cylinder of steam; and if
additional cylinders be connected by tubes with these two cylinders the
amount of power will be multiplied in proportion to the number of cylinders,
less the loss occasioned by friction. These additional cylinders are never in a
state of vacuum, but are always kept full of air, gas, or any other elastic or
non-elastic fluid not susceptible of condensation. When I employ air, com-
pressed air, or any other elastic fluid as the motive agent, it is in the same man-
ner as steam, admitted above the piston; and the same effect will result from the
same arrangement of cylinders and the connecting tubes, whether the cylinders
be two or more, with this difference, that the air which has followed the
piston must be withdrawn by air pumps out of the cylinder in order that there
may be a vacuum above the piston. When I employ a non-elastic substance
to force down the piston, to cause a vacuum by these means above the piston,
the same effect will result from the same arrangement of cylinders and
connecting tubes, be they two or more. I have shewn in the accompanying
Drawings some of the means whereby my Invention may be carried into effect.
Fig. 1 is a sectional representation of the most simple arrangement of
engine in which steam is the motive agent, and only two cylinders are em-
ployed. A is a cylinder filled with air, or any other elastic or non-elastic fluid,
under the piston B. The rod of the piston works through a stuffing box, and
is attached to a working beam in the ordinary manner. C is a valve in. a
pipe Q connected with a steam boiler. D is a valve in the pipe E, which
leads from the upper end of the cylinder to a condenser F, which is constructed
in the ordinary manner, and is furnished with an air pump G, as usual. O is

page_text: a tube which connects the cylinder A with the cylinder H, and is filled with
the same fluid as occupies the space in the cylinder A, under the piston B.
H is a second cylinder of similar dimensions to A, and is in a state of vacuum
above the piston I. This vacuum is caused by the condensation of steam, as
is. usually done. J is a valve in a steam pipe Q. K is a valve in the pipe L,
which leads from the upper end of the cylinder to the condenser M, which
is also furnished with an air pump N. In order to understand the action of
the engine, let all the valves in the first instance be supposed to be shut.
In order to set the engine in motion, the valve C in the steam pipe is to be
opened to admit the steam above the piston. B at the upper end of the
cylinder.A, and at the' same time the valve P in the air, tube O, which shuts
off the communication with the cylinder H, under its. piston I, is to be opened,
and the, pressure of the air, which is in the air tube O and cylinder A, under
the piston, will press on the under surface of the piston I, and there being a
vacuum on the other or upper side of this piston, it will ascend to the top of
'the cylinder H, at the same time this piston B in the cylinder A will descend
or be forced down, by the steam. On the piston B arriving at. the bottom of
the cylinder A, the valve C on the steam pipe is shut, and the valve D, in
the pipe communicating with the condenser F, is to be opened, and the steam
above the piston B will rush into the condenser, F, and a vacuum will be
formed above the piston B in the cylinder. A, and the space under the piston I
will, in its turn, be full of air. On opening the valve J of the steam pipe of
the cylinder H, the piston I will be made to descend by the pressure of the
steam, and the piston B will, at the same time, be made to ascend (by the
pressure of the air from the pipe O and the cylinder H,) into the vacuum
caused by the condensation of the steam which had driven the piston down,
consequently, by admitting steam alternately into the cylinders A and H above
the piston, the piston of these cylinders will be made to ascend and descend,
and communicate a reciprocating motion to the beam.
Fig. 2 is a partial sectional view, and Fig. 3 a plan or horizontal view of
another arrangement, in which two air cylinders are placed on the channel of
communication,, between the steam or end cylinders, so that the power of the
pistons of these two latter steam cylinders may be transmitted to the pistons of
the additional cylinders. A and H are the two steam cylinders, as in the other
Figure, and Z, Z, are the two additional cylinders. C is the pipe whereby
steam is admitted into the steam cylinders, and O, O, O, are the tubes which
connect the lower end of the steam cylinders below the, pistons with the air
cylinders.. F, F, are the condensers, and E the pipes leading from the upper
end of the steam cylinders to the condensers. R is a pipe for maintaining

page_text: communication between the top of the two air cylinders Z, Z. As all the
parts in all these Figures work in precisely the same manner as in the Figure
already described, it will not be necessary to enter into further detail, except
to repeat that the space below the pistons in the steam cylinders A and H, as
well as the connecting pipes O, O, and additional cylinders Z, Z, are filled with
atmospheric air or other non-condensible fluid; and as the pistons in the steam
cylinders A and H move they must put in motion this body of air, and conse-
quently actuate the pistons in the additional cylinders Z, Z. And the motions
of these pistons may, of course, by means of the piston rods, beams, and suitable
gear, be made use of to transmit power.
d
Fig. 4 represents a diagram of an air engine or machine constructed upon
my improved plan, and is intended to shew a new method of obtaining a
vacuum alternately in the cylinders A and H by the power which they carry,
for which purpose the pistons B and I in the two cylinders are connected by
their rods with 'the beam P, as shewn in the Figure. A is a cylinder in a state
of vacuum under its piston B, which is caused by opening the valve G in the
pipe which connects the lower end of the cylinder A with the vacuum cistern E,
which is maintained in a constant state of exhaustion or rarefaction 'by. the air
pump F, which, as well as the air pump M of the condenser L, is worked by
hand to start the engine. C is a valve which admits or shuts off the pressure
of the atmosphere. D is a pipe with a valve, which connects the upper end
of the cylinder A above its piston with the vacuum cistern E. P is the beam
which is worked by the pistons B and F in the cylinders A and H, by means
of the rods attached to the pistons. H is a cylinder filled with air above its
piston I, and O is a valve which admits or shuts off the pressure of the atmo-
sphere; J is a pipe, with a valve K connecting the upper end of the cylinder H
with the rarefied air or vacuum cistern L; M is an air pump for maintaining
this cistern in a constant state of rarefaction or exhaustion, and is worked by the
beam of the engine, or any other convenient means; N is a valve for connect-
ing the lower end of the cylinder H under the piston with the vacuum
cistern L. Let all the valves be supposed to be shut, on opening the valve in
the pipe G, and setting the air pump F to work, the 'air under the piston B in
the cylinder A is drawn out into the cistern E, and out of this cistern by the
air pump F, and when the cylinder A is in a state of exhaustion the valve in
the pipe G is to be shut, but the air pump F is to be kept constantly at work,
in order to maintain the cistern E in a state of exhaustion or rarefaction for
the next stroke. On opening the valve C in the cylinder A; the pressure
of the atmosphere is allowed to act on the piston B, and, on opening at the
same time; the valve K in the pipe J, the air which is in the cylinder H will

page_text: rush into the rarefied cistern L, and be drawn out of it by the air pump M.
The piston B will then be pressed down to the bottom of the cylinder A, and
the piston I will be raised up to the top of the cylinder H, and there will be a
vacuum under the piston I, while the space above the piston B, in the
cylinder A, will be filled with air through the valve C. As soon as the piston B
reaches the bottom of the cylinder A, the valve C, by which air is admitted
above the piston B, is shut.
Having briefly described the construction of the various parts, and their
connection with each other, I will now proceed to explain the action of the
engine. Let it be supposed that all the valves are shut. In order to start the
engine it will be necessary to set the air pumps F and M in motion by hand, or
by any other means, so as to exhaust the vacuum cisterns E and L, as well as
the space under the piston B in the cylinder A; then upon opening the valve
in the pipe G, so as to open a communication between the cistern E and the
spaces under the piston B in the cylinder A, this cylinder will soon be in a
state of exhaustion; the valve in the pipe G must then be shut and remain
permanently closed, and there will be a vacuum under the piston B in the
cylinder A, and the space above the piston I is filled with air, while there is a
vacuum in the cistern L. On opening simultaneously the valve C in the
cylinder A, which admits air above the piston B, and the valve K in the pipe
J, the air above the piston I in the cylinder H will rush into the vacuum
cistern L, which is in a state of exhaustion, and the air left in the space above
the piston I will, in consequence, be in a state of rarefaction, and will be
further rarefied or exhausted by the air pump M, and the pressure of the air
admitted through the valve C above the piston in the cylinder A, will cause it
to descend to the bottom of the cylinder A, while the piston I will simul-
taneously rise to the top of the cylinder H; the valve C in the cylinder A, and
the valve K in the pipe J of the cylinder H, must be simultaneously shut when
the piston B arrives at the bottom of the cylinder A, and the piston I arrives
at the top of the cylinder H. In this state of the operation the space under
the piston I in the cylinder H is in a vacuum, and the space above the
piston B in the cylinder A is full of air, and upon opening the valve O in the
cylinder H, which lets in the air, and opening the valve in the pipe D, the air
which is above the piston B in the cylinder A will rush into the vacuum
cistern E, and the piston I will descend to the bottom of the cylinder H, while
the piston B will rise to the top of the cylinder A.
In Fig. 5 I have shewn a modification of the above machine, in which
there are two other cylinders, of the same dimensions as the cylinders A and
H, with pistons and rods, and connected together by an air tube at the

page_text: bottom. Each of these piston rods is attached to a working beam, and two
separate engines of equal power are thereby formed. This is effected by
connecting each of these two cylinders at the bottom by a tube S, which,
as well as the cylinders, is filled with air or any other elastic or non-elastic
5 fluid. The cylinder A is connected with the top of the cylinder X by a pipe
G, furnished with a valve; and the cylinder H is connected to the cylinder Y
in a like manner by the pipe and valve O, and atmospheric air.is admitted into
the cylinders X and Y. above the pistons, when required, through the pipes
and valves. T and U. A communication between the cylinders A and H
above the pistons, and their respective vacuum chambers E and L, is esta-
blished by means of the valves D and K, and below the pistons by the valves
G and N; upon exhausting the vacuum vessels E and L, and opening the valves
G and K, the cylinders A will be exhausted under the piston, and the cylinder
II above the piston; then the valve 0 of the cylinder H, the valve C² of the
cylinder A, and the air valve U, as also the valves in the pipe S, are. simul-
taneously opened; the consequence will be that the piston B will descend, and
air will rush into the cylinder X above the piston through the pipe U, and the
piston of the cylinder Y will descend and force the air below the piston
along the tube S, into the cylinder Y, under the piston; which will con-
sequently ascend and force the air above the said piston into the cylinder A
above the piston. It will be evident that the valve K being open, the air
which is in the cylinder I will rush into the vacuum cistern, and the piston
I will of course ascend as the piston B in the opposite cylinder descends.
Upon opening and shutting the valves, as before described, the four pistons
in the four cylinders will move up and down simultaneously; and if more
cylinders be added the same effect will follow by merely connecting the
cylinder together by means of conducting tubes filled with air or any other
elastic or non-elastic fluid. The air pumps F and M are kept continually
in motion, and are worked by rods from the beam, or. by any other means,
and the valves may be worked by any of the well known means used for
similar purposes, and which need not be more minutely described. I would
here observe, that whereas in the engine shewn in Figs.. 1, 2,.and. 8, the
vacuum which is made to work the engine is obtained by the condensation
of steam. The vacuum in the engine, shewn at. Figures 4. and 5, is pro-
duced by pumping out the air; but either of these plans may be substituted
for the other in either machine upon making suitable arrangements, which
will be evident to any intelligent mechanic. One of the advantages resulting
from the above described means of producing a vacuum, by exhausting the
cylinders by means of air pumps, consists in the peculiar construction and

page_text: arrangement of the engine and contrivance before described, whereby I am
enabled to multiply the power and apply a portion of the said power to work
the air pumps. At Figs. 6, 7, 8, and 9 I have shewn a mode of applying
the principle above set forth as a means of propulsion on atmospheric railways.
Fig. 6 is a sectional plan, view, or diagram of the atmospheric tubes; Fig. 7
is a transverse section of one of the tubes; Fig. 8 is a plan view or representa-
tion of the upper side of the tube, shewing the longitudinal valve; and Fig. 9
is a longitudinal section of the tube, shewing the piston therein. I employ
two tubes, and connect them together at one end, and the vacuum in each tube
is alternately effected at each end, which is closed by a removable cover a;
the piston being at one end, the vacuum is formed in the space which
intervenes between the piston and the other end of the tube, as is usual in
cases of atmospheric propulsion. The piston is fixed at its centre to one end
of a rod of the necessary length, and the other end of the piston rod carries
a vertical rod which passes through the longitudinal valve or slit in the
propulsion tube, for the purpose of connecting the piston inside to the carriages
outside the tube. The slit valve or opening on the top of the tubė runs
longitudinally from one end to the other of the tube, and is closed or covered
by two lids of equal dimensions, which extend from each side of the longi-
'tudinal slit or opening, and meet in the centre with a gentle incline upwards,
as seen in Fig. 7. These lids are covered' on the inside with leather, or any
other suitable material, and their edges meet in the centre of the slit or
opening with a slight incline upwards. The lids which close the valve
may be mounted on hinges, and their edges are pressed together by a metallic
spring, and also by the pressure of the atmosphere, as the tube is exhausted,
by which the admission of the air through the longitudinal valve or opening
into the tube is prévented. The ends of each separate lid are pressed
together by springs, and kept tight by the pressure of the air. In every
length of lids the leather or other suitable material is in one uninterrupted
piece. The horizontal or piston rod, which is fixed to the centre of the
piston, may be the length of each separate lid, and the vertical rod fixed to
the end of the horizontal rod should be sufficiently long to pass through
the slit in the tube, so that the load on the outside of the tubė may be attached
to this vertical rod. The piston will be always in advance of the load the
whole distance of the length of the horizontal rod, the length of which may be
regulated by the space kept open in the slit by the diameter of the vertical rod
which connects the piston to the carriages. The length of each lid may be deter-
mined by the same rule. As the vertical rod separates the lids, air is admitted
into the tubes behind the piston, and by its pressure propels it forward, as in other

page_text: cases of atmospheric propulsion. There are two tubes, of equal diameter
and length, which are connected at the end by a cross tube of any suitable
diameter, and of any length, as is shewn in Fig. 6. B is the piston in a tube
A, which is full of air, the horizontal rod of which piston carries a vertical
rod b, which passes up through the slit in the tube A, as seen in Fig. 9, and
C is a tube which connects the propulsion tube A to a second. tube H.
The tube C is furnished with two valves D and G, which cuts off and opens.
the communication between the two tubes A and H, the latter of which
also has a piston E and rod F, with a vertical rod at its end to pass through
the longitudinal slit in the tube H, for the purpose of connecting together
the piston and carriage or train which is worked by the second propulsion
tube. It should be observed that each of the tubes A and H is alternately.
in a state of vacuum. In the Figure, A is supposed to be full of air, and H
in a state of vacuum; and the piston E in the tube. H will be set in motion
by opening the,, valves, D and G; and allowing the air to rush in behind it
from the tube A, which will cause the piston immediately to move, forward
in the direction of the arrow, while the piston B in the tube: A will will
immediately advance in the opposite direction.
Having now described the nature and object of my Invention, and the
manner of carrying the same into effect, I would observe that although I have,
to prevent unnecessary complication, generally spoken of steam as the motive
agent to be employed to give motion to the pistons in the end cylinders A
and H, it will be evident that air, compressed air, vapor, or other elastic
fluid, or any other pressure capable of exerting-power against the said pistons
may, upon making suitable arrangements, be employed in place of steam.
And I wish it to be distinctly understood, that although in the accompanying.
Drawings and foregoing, description I have. shewn, and described various
plans for practically carrying out the principle upon which my Invention is
founded, yet I do not by any means intend to confine myself to the details or
arrangement therein set forth, nor yet to the number of cylinders which may
be employed, as all these points may be altered, changed, or modified in various
ways to suit circumstances, without essentially departing from the principle
of my Invention. But what I consider to be new, and therefore wish to claim
as the Invention secured to me under the herein-before in part recited Letters
Patent is,
First, the mode shewn and described in Figs. 1, 2, 3, 4, and 5, of obtaining
and transmitting power or motion from piston to piston in any given number
of cylinders, and of applying the power or motion so obtained through the

page_text: medium of any of the ordinary mechanical contrivances to any purposes for
which power or motion may be required.
Second, the arrangement and construction of parts shewn and described
in Figs. 4 and 5, constituting an improved air engine.
Third, the peculiar mode, shewn in the said Figures, of producing a
vacuum alternately in each cylinder, and of transmittting the power or motion
so obtained from piston to piston, in any given number of cylinders, and of
applying the same by any suitable means to any purposes where power may
be required.
Fourth, the mode above shewn of constructing or closing the longitudinal
valve or slot of atmospheric railways, and the employment of two tubes, as
shewn, as also the mode of working or propelling the two pistons, whereby
the motion up and down is simultaneous, and power or motion may be
transmitted to any distance.
In witness whereof, I, the said James Nasmyth, have hereunto set my
hand and seal, this Eleventh day of August, in the year of our Lord