A NEW IMPROVED METHOD OF DRIVING CARRIAGES OF ALL KINDS, WITHOUT THE USE OF HORSES, BY MEANS OF AN IMPROVED OLIAN ENGINE, AND WHICH ENGINE MAY ALSO BE APPLIED TO VARIOUS OTHER USEFUL PURPOSES
Year: 1800

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I,, GEORGE
MEDHURST, of Battle Bridge, in the Parish of St. James Clerkenwell, in the
County of Middlesex, Engineer, send greeting...
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Second day of August, in the fortieth year of His-reign,
give and grant unto me, the said George Medhurst, His especial licence that
I, the said George Medhurst, during the term of years therein mentioned,
should and lawfully might use, exercise, and. vend, within England, Wales,
and the Town of Berwick-upon-Tweed, my Invention of "A NEW IMPROVED
METHOD OF DRIVING CARRIAGES OF ALL KINDS, WITHOUT THE USE OF HORSES, BY
MEANS OF AN IMPROVED OLIAN ENGINE, AND WHICH ENGINE MAY ALSO BE
APPLIED TO VARIOUS OTHER USEFUL PURPOSES;" in which said Letters Patent
there is contained a proviso obliging me, the said George Medhurst, by an
instrument in writing under my hand and seal, to cause a particular, de-
scription 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 one calendar month after the date of the said recited Letters Patent,
as in and by the same (relation being thereunto had) may more fully and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Medhurst, do hereby declare that my said Invention is described by
the Drawings hereunto annexed, and also by the description of such Draw-

page_text: ings, and such further description of my said Invention as is herein-after
contained (that is to say):-
The power applied to the machinery is compressed air, and the power to
compress the air I obtain generally by wind, assisted and improved by
machinery described in this Specification: and, in order to render my
Invention universally useful, I propose to adopt my machinery and magazine
so that it may be charged by hand, by a fall of water, by a partial vacuum
obtained by wind, and also by explosive and effervescent substances, for the
rapid conveyance of passengers, mails, dispatches, artillery, military stores, &c.,
and to establish regular stage coaches and waggons throughout the kingdom
to convey goods and passengers for public accommodation, by erecting wind-
mills, water mills, &c. at proper intervals upon the roads, to be employed in
charging large magazines at those stations with compressed air, or in raising
large reservoirs of water by wind, &c., by the power of which smaller portable
magazines may be charged, when required, by machinery for that purpose.
Figure the First is a single pump to condense the air in a receiver or
magazine by hand or any uniform power. A, B, are two toothed wheels that
turn each other. The handle is fixed upon the spindle of B, and upon the
same spindle is a fly wheel C. Upon the end of each spindle, and on the
outside of the frame D, D, that support them, are two cranks that, in con-
sequence of the wheels turning each other, turn contrary ways. Two crank
rods F, F, are attached to these cranks, which have their other end jointed
to the piston rod G, which works the piston H in the barrel I. As the piston
goes down the air is condensed, and driven out of the barrel through the
valve m and pipe o, and into the magazine that is to be charged, which is
screwed to the end of the pipe for that purpose, and the barrel is supplied
with air through the valve n as the piston ascends. To condense the air in
the magazine by a windmill I construct a double pump, variable by a com-
pound beam, as follows:-In the middle of the iron horizontal axis of the
windmill sails is formed a triangular crank X, X, Figure 2, to which the
perpendicular shaft N, N, is connected by a swivel socket, which this turns
upon the crank, but is-prevented from sliding longitudinally by the collars on
each side of it, and by means of which it may be placed on any part of the
crank. This shaft passes the lever R, R, and goes through a socket in the
end of the lever O, P, O. There is a nut above and below this socket, so that
the shaft in its motion up and down gives the like motion to the lever O, P, 0,
which turns upon a centre at P: The lever R, R, is moveable upon a
the end of the lever O, P, O, by the
spindle at Q, and is connected to
piece L, O. At the end of the lever R, R, is jointed the piston rod S, T, V,

page_text: which works the piston V in the barrel B, and which has a joint and wheel at
T, that moves up and down the guides E, E, to preserve the parallelism of
the rod. The end 0 1 of the lever O, P, O, is connected by the piece O, s, to
the lever D, D, which works the other piston C in the barrel A. The
levers R, R, and D, D, are so placed as to be parallel to their respective
ends of the lever O, P, O, when their respective pistons are at the bottom of:
the barrels, for by this means the piston will always wash the bottom of the
barrels, altho' the length of the stroke should be ever so much reduced. There
are two valves at the bottom of each barrel, one of them to admit the air from
the atmosphere when the piston ascends, and the other to admit the air from
the barrel into the pipe W, which leads to the magazine, when the air is suffi-
ciently condensed by the descent of the piston. In order to adjust the stroke
of the piston to the strength of the wind and the density of the air in the
magazine, so as to obtain the full effect of the wind at all times, the con-
necting picces O, L, and O, s, are furnished with machinery by which they
shift themselves upon their respective levers. This machinery consists of two.
small wheels o, n, the teeth of which work in each other, and also in the two-
straight racks m and fixed to the levers. Upon the axis of the wheel n is a
strong barrel spring, which constantly tends to turn the wheel round, and a
small fly wheel v attached to it, which motion of the wheel n would move the
piece O, s, towards the centre of the lever P; but, to counteract that motion,..
there is a vibrating ball u, the arm of which moves upon an axis under the
wheel n, and has a pall p upon the end of it, which, when it vibrates suffi-
ciently, catches hold of one of the teeth of the wheel n, and moves it the.
contrary way. Therefore, with a certain degree of velocity in the lever O, P, O,.
these two contrary motions balance each other, which keeps the piece O, s,
stationary; but when a greater degree of velocity prevails in the lever, owing
to increase of wind or weakness of the air in the magazine, the ball u will
make a greater vibration, which will move the wheel n through a larger arch
of the circle, and increase the distance of O, s, from the centre P, whereby the-
stroke of the piston C will be increased in length. On the contrary, when the
arch of vibration of the ball u is small, the regular approach of the piece O, s,
to the centre P by means of the spring will be greater than the vibration of the
ball u can carry it back, which will cause the piece to approach the centre P,
and of course the stroke of the piston to be shortened; and the same is to be
understood of the other connecting O, L.
Figure 3 is a machine to compress the air, so as to charge a small magazine
to a very high degree by hand. A, A, is the axis of the handle, the end of
which turns in a strong stud at a; and at that end is a worm d of a single

page_text: thread, acting in the teeth of a small wheel fixed upon the lower end of the
upright screw B. The nut or female part of this screw D is fitted within the
frame C, C, and is capable of turning. round within it, together with 'the'
wheel D, which is fixed upon the nut. This wheel acts upon another wheel E,
of the same size, which slides up and down upon the straight flat bar F, F;
and upon the lower end of this bar is a small bevel wheel F acting upon a
vertical wheel G fixed upon the axis of the handle. Under the top of the
machine is a broad and strong bar of iron I, I, having a small motion by a
joint in the top.at C, so that the other end may fall-down from the plate about
one inch. In this bar is fixed the steel pin d, which enters into the top of the
screw Band sustains the force of the pressure when the machine is in actión.
Upon the end J, 'e; of the bar I, I, is a' rod e, 'g, suspended, the lower end of
which takes hold of the crank g, hi. This crank turns upon a fixed center
ath; and the arm is forked, and works in a grove in the sliding box i, m,
which moves-upon a square part of the axis of the handle: Upon the under
side of the frame:C, C; and just under the nut D, are screwed the two iron
rods M, M, which are attached to the piston N, within the cylinder O; in
which the air is compressed; and at the bottom of the cylinder are two
valves and p, the first to admit the air into the cylinder from the atmosphere
when the piston ascends, and the latter to admit the compressed air to pass
from the cylinder into the magazine which is to be screwed while it is charging
to the other end of the pipe p, p. As the handle is turned round the worm a
turns the small wheel on the end of the screw B, which causes the nut D and
the frame C, C, with the wheels D and E, to descend, and by means of the
rods M, M, to press down the piston N, and to compress the-air under it.
The use of the frames-C, C; and the wheels within it, with the top bar and
apparatus upōn-the axis of the handle, is to facilitate the motion of the piston
both upwards and downwards; for, when' the pressure against the piston N is
moderate; the end I, e, of the bar I, I, will fall into the position here repre-
sented; and in this position the crank h, i, suffers the sliding box i, m, upon
the axis of the handle to take hold of the wheel G, by which means the
wheels G, FE,-and-D,- are turned round, together with the nut D, with a
velocity equal to that of the handle; and the nut, rods, and piston will move
up and down with rapidity. But when the pressure against the piston becomes
violent the force of the screw will lift up the bar I, I, and drive it close up to
the top plate of the machine, which, by means of the rod and crank g, h, i,
will draw the sliding box i, m, from the wheels, and set it at liberty, when all
the wheels and the nut will be motionless, and the pressure be produced by
the worm a and wheel and screw B. As the frame C, C, moves up and down

page_text: the,wheel. E slides upon the bar F, F, which is made flat for that purpose;
and the center hole of the wheel is made to fit so as to slide; but not to turn
without the bar; and the lower side of the wheel D that is fixed upon the
nut must lay flat upon the inside of the frame, otherwise the nut. will be
liable to turn round when it should be stationary....
Figure 4-is. a. circular moving variable piston, applicable. to light .carriages:
A, A,, is a cylinder of. iron or copper, firmly fixed to the bed of the carriage,.
and concentrical to the hind axletree. Each end is open, and has an outside.
flank. B, B, is another cylinder within the first, and concentrical.also to.the
axletree. These cylinders differ in diameter about one fourth of the diameter
of the largest... C, C, is a flat metal ring, ground air-tight to the flanch of the
cylinder A, A, and confined to it by a rebated edge all round, screwed to the
flanch of. A, A. The inner edge of the ring C, C; is leathered, and fits tight
upon the cylinder B, B, and moves round with.it. The piston p, p, is fixed fast
to the cylinder B, B: it passes through the notch & in the flat ring:C, C, (see
Figure ) and is made to fit close to it, and also to the inside of A, A, for
which purpose the top edge of it is leathered. p, q, Figure 6, is another flat
ring, leathered upon the top edge, and made to fit to the inside of A, A. This
ring does not turn round, but is kept close to the end of B, B, by a rebated
edge p, q,.Figure 4. c, e, is the stop, which is a flat plate of metal, made-to
fit and fill up the space between the two cylinders: it passes through. a notch
in.the cylinder A, A, which is leathered to keep it close. The inner edge of the
stop is leathered also, to fit close to the.cylinder B, B. U is.the cock that admits
and shuts out the air of the magazine M. This cock is opened and shut by two
studs in the flat ring C, C. The dense air, being admitted from the magazine
into the cylinder between the flat side of the piston and the stop, drives round
the piston and cylinder B, B, with the axletree of the..carriage; and as the
piston comes round to the stop.it .presses it down by its iuclining edge, and forces
it to slide through the notch of the cylinder A, A, whereby it has liberty to pass
by, and the stop is thrown into its position. again by a spring i on the outside!
On the side of the stop. in the cylinder A, A, is a hole, always open to admit
the air to pass out of the cylinder when it has driven round the piston. The
magazinė M. niust lay upon a wooden bed between the wheels of the carriage
and parrellel to the axletree, and must have a stopcock to screw the pipe of
the condensing machine to when it is charged.. One of the studs in C, C
must be so placed as to open the cock u the instant the stop c, e, falls into its
position. But the other, that shuts the cock, is placed upon different parts of
the ring C, C, which has several holes in it for that purpose, and it is to be
regulated by the velocity of the engine. When it is too slow the variable pin

page_text: must be removed further from the fixed one, and vice versa.
When a greater
power and variation is required than I can obtain by the circular moving piston,
I construct the machinery, and apply it to the carriage as follows:-
Figure 7, A and B are two cylinders of equal length, but of unequal
diameter, so that one of them may be of twice the capacity of the other; they
are placed close together, and closed at top. Each of them is furnished with
a piston and rod, and a valve in the top plate, opening inwards, both supplied
from the magazine through the pipe C, and through the same valve in the
valve box c; but each of them have a stopcock a and b below the valve, so
that either of them may be used separately or both together. To these two
cylinders I apply a compound beam and a spiral wheel, by which means I can
vary the power of the engine from one to twenty times, as circumstances require.
The foot of each piston rod is united into the lever F, which is made sufficiently
broad for that purpose." This lever, which is one part of the compound beam,
moves in a joint in the short arm at H, and the short arm is fixed upon a
spindle I, which moves upon its two bearings at the ends. This spindle must
be something longer than the piston rods are apart, to prevent the lever from
turning on one side when the cylinders are used separately. Within the lever
Fare two small rollers d, d, with a perpendicular rod e fixed between them,
which preserves the parrellelism of the piston rods, and the use of the short
arm H; I is to give liberty to the lever F to move endways as the perpen-
dicular rod e directs it. The end of the lever F passes through one end of the
connecting pipe L, and the end of the lever M (which makes the other part of
the compound beam) passes through the other end of the piece L, which is
moveable backwards and forwards upon them. The two levers must be so
placed that they may lay parrellel to each other when the pistons are quite at
the top of their cylinders; otherwise, when the stroke of the pistons are
shortened, they will not come up to the top, which will occasion a loss of power,
because the air will be delated before it begins to act upon the piston. The end
of the lever M turns upon a fixed centre at N, and upon it at M is jointed the
crank rod P, which communicates to the crank Q upon the centre and spindle
of the wheel O. This wheel is bevel-toothed, and turns two other equal-and
horizontal wheels R and S contrary ways. That part of the vertical spindle that
is below the wheel R is square, and has upon it another wheel T, which turns
the vertical spiral wheel B, fixed upon the axletree of the carriage. The two
wheels R and S upon the vertical spindle are locked thereon by a coupling box,
and either of them may be set free at pleasure by a lever upon the coupling
box, and the locking of one sets the other at liberty. When the wheel S is
locked, the wheel O acting upon it, will give the carriage a direct motion; but

page_text: if the wheel S is unlocked, and the wheel R locked, the carriage will receive a
retrograde motion. The wheel T is made to slide up and down upon the
vertical spindle by a lever for that purpose, and upon the under side of it there
is an edge projecting all round, which runs in a groove in the spiral wheel. The
use of this edge and groove is to conduct the teeth of the wheel T when
pressed by the lever down the spiral part n, L, of the wheel V into the smaller
circle of that wheel, so that the wheel T may work either in V, the larger circle, or
P, the smaller circle, at pleasure, and be shifted from either one to the other,
while the machine and carriage is in motion. When the wheel T works in V the
power of the engine on the carriage will of course be proportionably greater than
when it works in P; and when the connecting piece L is moved towards the end
H of the lever F, and towards the end of the lever M, the stroke of the piston will be
lengthened, so that a larger quantity of dense air is used, and a proportionably
greater power acts upon the carriage; and also, if the two cylinders are used
together, the power of the engine to drive the carriage will be three times
greater than when the small one is used only. In waggons and coaches heavy
loaded, and upon bad and hilly roads, it will be found necessary to use all the
means of power or velocity combined, as here described; but in good and even
roads one of the cylinders and the uppermost lever of the compound beam may
be dispensed with, even in carriages of the greatest burthen. The horizontal
wheel S acts upon the small wheel m, fixed upon the spindle of the fly wheel
X, which is of as large diameter as can be admitted between the carriage
wheels, and about one twentieth part of the weight of the carriage and
burthen. Y, is a spring box, which contains a spring of sufficient strength to
draw the crank up by the chain h into the position here represented: when the
wheels R and S are detached from their spindle, its use is to place the crank
in a fair position for the action of the rod P when the carriage is first started.
The axletree of the carriage should be capable of turning round within the
nave of one of the wheels, and have a ratched wheel with side teeth fitted upon a
square part of it, close to the inside of that nave, on which is another similar
ratched wheel, so that the teeth of the one lock into the teeth of the other, when
they are pressed together by a spring upon the axletree for that purpose, and
by that means connect that wheel and axletree together also. The use of this
contrivance is to enable the carriage to turn round with greater facility. Z, Z, is
the portable magazine, which is a cylinder with globular ends; it has a pipe C
screwed to it, that leads to the top of the cylinders; it must also have a stopcock,
to which the pipe of the condensing engine is to be screwed when it is charged.
The magazine for light carriages will lay parrellel to the axletree between
the wheels of the carriage, and may be from twelve to twenty-four inches in

page_text: diameter, and about four feet long; .but for heavy carriages it must lay parrellel
to the direction the carriage moves in, as represented. in this Figure; and of as
great length and diameter as can be admitted; and when it is. required, to
drive à carriage far witli onc. charge it will be necessary to have an additional
carriage, on which the principal part of the machinery and magazine should be
supported; and in this case the magazine might, be, globular, which is the
strongest and lightest of all forms for the purpose. An iron cylindrical
magazine, of two feet diameter, charged with air sixteen times condensed, the
substance of the iron must be one twentieth part of an inch; but a globular
magazine, of the same metal, diameter, and charge, need be but one fortieth
part of an inch in substance..
...
The engine to charge one magazine to any required degree by another of a
less degree of condensation is represented in Figure 8. A. is the section of a
cylinder closed at top and open at bottom. B, the piston, the rod of which.com-
municates to the end of the compound beam D, having a joint at C, and a roller
that passes between the guides E, E. The beam D moves on a. fixed centre
at F; and: is connected to the other beam G, H, by the piece I. The beam
G, H, moves upon a fixed centre at L, and is connected to the crank of-the
flywheel by the rod M; that is jointed to the end G.of.the beam. To the
other end of the beam at H is jointed the rods N, N, which have held of the
pins of the quadrant 0,0; these. quadrants have each a socket at their
centre P, and. both. turn upon one fixed spindle. R, R, are two other rods
attached to the quadrants by two other pins, and communicate from the quad-
rants to the piston of the 'cylinder S. This cylinder is closed at top, and.in
the top are the two self-moving, valves a and,b; there are also two valves
c and d in the top of the cylinder A, that are opened and shut by a,plug tree,
.inoved by the beam in the manner of a steam engine. This engine is worked
by the dense air from the fixed magazine entering the, cylinder A by the
valve c; which drives down the-piston and the end of the beam D, and also
the end G of the beam G, H, and forces up the end H with the arch of the
quadrant and piston of, the cylinder S. In this cylinder the air is condensed,
fand, driven out at the valve a, through the pipe, and into the portable magazine
.screwed to the end of it, and the cylinder is supplied with air as the piston
descends.by the valve, b. The use of the quadrants are to equalize the force,
and the fly wheel to equalize the motion. The levers or beams D, F,-and
G, H, of the compound beam must lay parrallel to each other when the
piston B is at the top of the cylinder, otherwise it will not ascend to the top
when the stroke is shortened. The connecting piece L is made to shift along
the two levers of the compound beam, to vary the length of the stroke of the

page_text: piston B, as a greater or less degree of power is required, and which may be
made to shift itself as described in Figure 2, if required..
I
Figure 9 is the machine or engine to be driven by compressed air obtained
by fixed gunpowder and other explosive or effervescent substances. Ais
a strong wrought iron cylinder, made much stronger at the end B than
at the other end; this end is covered by a flat plate of iron, which is screwed:
fast to it with an air-tight joint. In the middle of the plate B is a strong.
pipe 'a, about five inches in length, through which is a copper plug of a stop-
cock-b, that is-ground air-tight into it, so as to stop the aperture of the pipe
and prevent the explosive substance from entering, or the air produced by
that substance from escaping out of the cylinder. In the plug are two
cavities opposite to each other, and each coinciding with the bore of the pipe;"
they are not made through the plug, but of sufficient capacity, to hold *so
much powder or other explosive substance as is intended for one discharge,
which for an engine of one horse power sliould-be one fifteenth part of a cubic
inch, and the cylinder for that power about four hundred times as large.. C is*
a funnel of tin to hold a small quantity of the explosive substance and con-
duct it down to the cavity of the plug, where it is introduced-into the cylinder
by turning the plug half round. The funnel C must be supplied-from-time to
time either by hand or by another funnel, pipe, and plug-like the first, but
larger and at a distance from it. D is the piston of the cylinder; the rod
of 'it goes through the stuffing box in the plate F, which covers the other end
of the cylinder; and is screwed to it with an air-tight joint; the rod is jointed
to a cross bar at G, to the ends of which are jointed the two quadrant
rods f, f, the other ends of which have hold of the pins in the quadrants 9, g;
the quadrants. are toothed upon their arch, and work in each other. At
the other end i, i, of the arch of the quadrants are jointed two other rods
that meet at D; where they are jointed to the crank rod D, H, which takes
hold of the crank upon the axletree of the carriage. The two quadrants are
fixed upon two spindles s, s, on the other end of which, and on the other side
of the cylinder, are two other similar quadrants and rods, and also a similar
crank rod, all of which act together when the piston moves, and which keep
the piston rod parallel in its motion, and also equalizes the force of the dense
air. On the axletree of the carriage is a small toothed wliecl I, which turns
another at right angles to it, fixed upon the end of the long spindle I, b, and
upon the other end is a wheel, which turns another of twice the number of
teeth fixed upon the plug of the stopcock; by these wheels the plug is turned
half round in every revolution of the axletree, which brings one of the cavities
filled with the explosive substance within the interior part of the cylinder

page_text: every time the piston arrives at that end. The explosion is made by a flint,
agate, or diamond wheel placed within the piston at D, which has on its axis
a small pinion which works in a rack, the end of which strikes against the
plate as the piston drives it on, whereby the wheel makes a revolution upon
the steel placed above it. This method is effectual also to explode such sub-
stances as explode by friction, as well as those that explode by fire. In the
plate B is a valve which opens inwards, through which the air escapes as the
piston advances towards the plate B, after it has driven down the piston,
when the superior air of the atmosphere causes it to open, and it is shut by
the piston when it comes up to the top. In the plate F also is a small valve
that opens inwards, and which is opened by the superior weight of the
atmosphere when the piston is at top, and kept shut by a spring; its use is
to keep a quantity of air between the piston and plate F, which acts as a
spring to return the piston towards the plate B. Upon the middle of the
front axletree is fixed an horizontal circle, A 1, on which the front bed of
the perch rests; the fore part of this circle is toothed, see Figure 10, and the
teeth of the vertical wheel B work in them; this wheel is turned by a
screw o, the spindle of which is o, o, in Figure 9, and on the top of it is a
pully that carries the reins by which the pully and spindle o, o, is turned
round either way, and the axletree set to any angle required; and this method
is to be understood to be applied to the other carriages. The lightness and
strength of the machinery I obtain by making the cylinders, wheels, spindles,
and levers of wrought iron and steel, and hollow when it is practicable, and
by making the magazine of pure wrought iron or copper bound with strong
flaxen cord. To raise a reservoir of water for the purpose of charging port-
able magazines, &c., I apply the speer of a double hydraulical pump made in
the usual form, to the triangular crank upon the axis of the sails X, X,
Fig. 2, with a rack and wheels as described, also in Fig. 2, to lengthen or
shorten the stroke of the pump as the strength of the wind requires, and
to produce a partial vacuum in a magazine or air chamber. I make the
four valves at the bottom of the barrels A and B, Fig. 2, to open and shut
contrary to the Figure, viz, those two that are represented to, open- inwards
must open outwards, and vice versa.
In witness whereof, I, the said George Medhurst, have hereunto set my
hand and seal, the First day of September, in the year of our Lord
One thousand eight hundred.
GEORGE MEDHURST (L.S.)

page_text: AND BE IT REMEMBERED, that on the First day of September, in the
fortieth year of the reign of His Majesty King George the Third, the said
George Medhurst came before our said Lord the King in His Chancery, and
acknowledged the Instrument aforesaid, and all and every thing therein con-
tained and specified, in form above written. And also the Instrument aforesaid
was stamped according to the tenor of the several Statutes made in the sixth
year of the reign of the late King and Queen William and Mary of England,
and so forth, and in the seventeenth, twenty-third, and thirty-seventh years
of the reign of His present Majesty King George the Third.
Inrolled the First day of September, in the year of our Lord One thousand
eight hundred.