IMPROVEMENTS IN TRACTION AND LOCOMOTIVE ENGINES
Year: 1870

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN TRACTION AND LOCOMOTIVE ENGINES." -A communi-
cation from abroad by James K. Lake, of Chicago, County of
Cook, and State of Illinois, United States of America.
Sealed the 22nd July 1870, and dated the 3rd May 1870.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 3rd May 1870, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
TRACTION AND LOCOMOTIVE ENGINES," and have petitioned Her Majesty to
grant unto me, my executors, administrators, and assigns, Her Royal

page_text: Letters Patent for the same, and have made solemn Declaration that
it has been communicated to me from abroad by James K. Lake,
of Chicago, County of Cook, and State of Illinois, United States of
America.
NOW KNOW YE, that I, the said Alexander Melville Clark, do
hereby declare that the following Complete Specification, under my
hand and seal, fully describes and ascertains the nature of the said
Invention, and in what manner the same is to be performed, in and by
the following statement, reference being had to the two Sheets of
Drawings hereunto annexed, and to the letters and figures marked
thercon (that is to say) :-
This Invention relates to improvements in traction engines. The first
part relates to the mode of applying the power and varying the speed of
the driving wheels relatively to the engines, and consists in the employ-
ment with the main driving axle to which the propelling engines arc
connected, and with the driving wheels which are fitted loosely thereon, of
friction clutches for making or breaking the connection with the engines,
and in connection therewith it consists in the employment of a secondary
set of driving and auxiliary supporting wheels of smaller diameter than
the first geared down by means of belts or chains, or it may be gear
wheels working on loose drums on the main driving axle to be connected
therewith for transmitting motion, also by friction clutches, the said
secondary set of wheels being mounted on the frame in supports wherein
they may be vertically adjusted so as to shift the burthen of the carriage
from the primary to the secondary set, or vice versa, without interrupting
the forward motion of the carriage. The object of this part of the Inven-
tion is to so apply the power that in starting the carriage the engine may,
when the clutches are disconnected, be set in motion and be permitted to
attain considerable speed and develope a larger means of power than if
positively connected and compelled to set the whole mass in motion by
their initial movement, so that the clutches may be brought gradually
to apply the power to set the carriage gradually in motion. A further
object is to be able without stopping the carriage to change the applica-
tion of the power from one set of driving wheels to another geared for
a different rate of speed, the one being suited for level and smooth roads,
and the other for ascending grades and heavy roads with slow speed.
And a further object is to be able to break the connection with one
wheel when going around short curves to avoid the slipping of one

page_text: wheel which must occur when the driving power is positively connected
to both wheels.
The second part of the Invention relates to improvements in the con-
struction of the friction clutches, and has for its object to provide
clutches with sufficient holding power to ensure positive connection
when wholly pressed together with clutches of the least possible size and
without requiring too much end pressure on the sliding part. Also to
provide clutches which may be used in a manner to let the engines
overrun the wheels by slipping one part on the other in starting the
carriage, and in overcoming temporary obstructions without cutting and
wearing too fast, also without heating and welding the parts together,
for which it is of course necessary to lubricate the parts, which would
cause complete failure of the holding power if constructed on the angles
or pitches commonly used in the dry friction clutches. The improve-
ment therefore consists in constructing the wearing faces of the clutches
on such an acute angle with the shaft whercon they work as to possess
the necessary holding power when running in oil and with but little
end pressure or resistance to separation, all of which. is attained with
comparatively small clutches. It also consists in making the sliding
parts of the clutches in two parts, divided so that the one part carrying
a collar to form the outer wall of the groove for the crotched arm may
be tapped into the large tubular bore of the other part and screw up to
bring the collar parallel with the hub of the other part which forms the
other wall of the groove, the parts being held in any required position
by a set screw; the object being to adjust the parts from time to time
to take up the lost motion due to the wear by the crotch, and to renew
the part screwing into the other part when worn out without the waste
of the latter.
The third part of the Invention relates to the apparatus for shifting
the connection from one set of wheels to the other, and consists in the
arrangement of the crotched arms for shifting the clutches to have a
motion parallel to the driving shaft, to prevent the wear on the grooved
hubs of the clutches to a considerable extent, which is greater when the
said crotches vibrate in circular lines, owing to the variations of the
bearing surfaces on each other. It also consists in an arrangement
with cach pair of clutches of a pair of shifting levers and a pair of
shifting screws, the latter to be moved simultaneously by one and the
same motion of the hand for simultaneously connecting or disconnecting

page_text: each clutch of a pair, or for moving one independently of the other for
connecting or disconnecting one clutch only when required.
The fourth part of the Invention relates to changing the support of
the carriage from one set of driving wheels to the other, and consists in
the connection of the journal boxes of the shaft of the secondary pair of
wheels with the carriage frame by means of hoisting and lowering
screws for shifting the wheels to take the burthen from the primary
wheels, or to return it to them, and in connection therewith in the
application to the screws of reversing pinions and a sliding support for
the latter for gearing the screws with pinions on the end of the axle,
whereby the hoisting and lowering is effected by the axle through the
motion imparted to it by the belts or chains. It also consists in the
arrangement of the sliding supports of the reversing pinions on an
oscillating shaft or arms thereof, mounted on the journal boxes of the
axle to be moved up and down by it; the said oscillating shaft being
provided with a shifting lever, arranged to be shifted by hand, for con-
necting the shifting gear, and automatically by a cam or cams for
disconnecting it.
The fifth part of the Invention relates to mounting the guiding
wheels for the necessary universal vibrating motion, and to the guiding
apparatus therefor, and consists in mounting the axle, which is provided
with a vertical disk at its centre, on centre pins, to oscillate vertically
in a vertically slotted enlargement of a spindle mounted in an attach-
ment of the frame above the said enlargement, to oscillate horizontally,
and with a spring between the enlargement and the said attachment
of the frame, the lower end of the spindle being journalled in a brace
crotched at the end attached to the frame and hinged thereto, to
compensate for the up-and-down movement of the frame due to the
spring.
It also consists, 6thly, in a connection of the swinging end of a
tongue attached to the axle near each wheel by two arms of a crotch to
a segmental wheel placed in a circular guide at the bottom of the frame,
with which segment is geared a pinion on the lower end of a vertical
shaft worked by a belt passed several times around a pulley at the top,
and winding on and off a shaft near the front of the boiler worked by
a hand wheel.
The seventh part of the Invention relates to the construction of the
supporting frame, and consists in making the side and end bars of sheet

page_text: metal bent into U form and connected across the space at the edges of
the bent plate with cross stays, which bars are inverted when placed in
the machine, forming an oval upper surface, from which the housings or
pedestals for the support of the axles of the driving wheels are suspended
and on which the boiler supports are fastened, and the sides are connected
by suitable transverse bars.
The eighth part of the Invention relates to the construction of the
wheels, and consists in providing the broad sheet metal rims with two
rows of sockets formed by metal cups attached to the rims for the outer
ends of the spokes, and in arranging the spokes obliquely across
the vertical plane of the centre of the wheel for bracing it, also in
providing adjusting nuts on the spokes to be screwed against the face
of the hub for maintaining the proper tension on the rims of the
wheels.
The ninth part of the Invention relates to the arrangement of the
water tank and mode of attachment to the boiler, whereby one wall of
the tank forms the end covering of the boiler, against which the caloric
current impinges in passing from a lower set of tubes to an upper set,
in which it returns to the smoke stack at the forward end of the boiler,
and it consists in attaching the water tank, made in semicircular form,
or nearly so, on to the rear end of the boiler, forming a prolongation of
the same, and conforming at the rounded end with the conformation
of the frame of the machine. The end of the tank fitting the boiler
is provided with a circular flange entering the end of the same, and
secured thereto by screws passing through the shell into the said

page_text: axle F, which is arranged in bearings F³ in the housings F" suspended
from the side rails A. The driving wheels B are fitted to the axle to
work loosely thereon, and carry on their arms or spokes the female
parts F of a friction clutch, the male parts of which F are splined or
feathered to the axle F2 so as to be revolved by it, yet slide thereon to
and from the parts F5 for applying the power of the said driving wheels
or not, as required, also for relieving the engines at first starting, to let
them attain a high speed and corresponding measure of power, to bc
applied gradually by forcing the clutches together, so that they will
slip to some extent until the carriage attains sufficient motion to admit
of forcing them wholly together to make the connections complete and
positive. It will be seen that the hubs of the wheels B bear against
the bearings F' of the axle, which in turn bears against the inner faces
of the cranks, which are so firmly connected to the axle that the end
pressure on the clutch to produce the friction cannot possibly move the
female part out of its true position, but to avoid the friction on the
cranks I may place collars on the shaft next to the hubs of the wheels.
These main driving wheels B are intended to be used mainly when the
carriage is running along a level or nearly level road, and at the highest
rate of speed or thereabout, for which it is geared when connected with
them, but for going up steep gradients, over heavy roads, or for drawing
heavy loads, when it is desirable that the carriage should proceed slowly,
it is necessary, in order to admit the engines to run at their maximum
speed, which they must do to maintain their maximum power, to reduce
the motion of the driving wheels relatively to the engines. In some
cases it is desirable to do this without stopping the machine. For
effecting this change I employ a secondary set of supporting wheels C,
preferably of smaller diameter than the wheels B, and arranged for
moving up and down on the frame to shift the support of the carriage
from the main wheels to these secondary wheels by reducing gear, con-
necting with the main axle F2, so that they will be set in motion by
friction clutches in the same manner as the wheels B, the latter being
disconnected simultaneously with the connection of the said secondary
wheels. For imparting the motion to the secondary set and reducing
it I employ secondary friction clutches and chains G working over the
drums G of the female parts G² of the secondary friction clutches
placed on the main axle inside of the clutches of the main wheels, G³
being the male parts of the said secondary clutches. Other connections,
for example, cog wheels, may be used in place of the chains. Like the

page_text: arrangement of the clutches for the wheels B-the parts G' of the auxiliary.
clutches are free to revolve on the shaft, but not to slide, while the male
parts Gs slide to and from the others, but are feathered to the shaft..
These clutches being provided with suitable means for shifting them
readily it will be seen that the shifting for connecting the power or dis-
connecting from the main shaft may be effected while the engines are
in motion, so that not only in starting but in case such. bad roads aro
encountered as to overcome the power and gradually stop the machine
the engines may be relieved and allowed to attain high speed and
momentum, as before described for starting, and then be brought into
connection again, so as to force the wheels over temporary obstructions.
To make it possible to employ friction clutches in this manner it is
necessary to construct the friction surface upon such an angle or pitch
as to insure the greatest possible measure of adherence while in contact,+
without offering too much resistance to the shifting bar when releasing
or disconnecting the parts, and while affording the necessary amount of
adherence they must also be protected from grinding and cutting, and
be capable of slipping to let the engines overrun the wheels without
injury to the parts. Therefore I make the bearing surfaces of theso
friction clutches on a pitch of one inch rise to six to eight inches breadth
of face, or within the angle of to seven to ten degrees from the line
parallel with the shaft, and run them in oil or other lubricating sub-
stance; and I have found by practical demonstration that clutches
constructed within these limits possess a very much greater holding.
power when used in oil than others of the same size used dry, as in the
common way; also that the end pressure in the male part to cause
adherence and the force required for separating the parts are very much
less than in the common clutches. I propose in practice to make the
male parts of the clutches in two parts, divided on the dotted line H, and
connected by screwing the parts Hunto the other part, and securing them.
by set screws or otherwise, so that the lost motion in the grooves for the
crotched shifting bars H³ due to the wear may be taken up when required
by screwing the parts H¹ further in, or so that new parts may be sub-
stituted when they become worn. The crotched bars H3 and H' arc
fitted on a bar H5 supported in a stud H attached to the boiler, so that
they may move parallel with the axle F2 to have less wearing effect on
the walls of the grooved hubs. The bars H' are connected to levers H
pivoted at Hº to supports attached to the boiler, and they are connected

page_text: at their upper ends, the one to the screen shaft I and the other to the
screw threaded sleeve I' mounted on the top of the boiler near the front
end in the support I². The shaft I works in the sleeve I³, and each has
at one end a hand wheel I³, I*, placed side by side, so that they can
both be turned together by one hand, or one may be turned inde-
pendently of the other. The screw threads of the said shafts and sleeve
are pitched in opposite directions, so that by turning them in one
direction the levers H³ will be moved towards each other at the top and
from each other at the bottom, in which case they will force the male
clutches F into the female parts F³, and when the shafts are turned the
other way the clutches will be disconnected. The bars I* of the other
clutches are provided with a similar shaft I' and sleeve I' mounted in
the top of the support' I³, and provided with hand wheels, I', I³, for
operation in like manner. The axle C of the secondary set of wheels C
is mounted in bearings C² fitted to slide up and down in the houseings C³
on the radius of a radial line extending to the axis of the main shaft F2,
and they are provided with extensions C at the inner ends, and C³ at
the outer ends. The latter are slotted for the application of the bevel
pinions C on the ends of the axle, and they are supported on the vertical
.shafts C7 passing vertically through them, and having collars C³ within
hollow spaces in the said extension, or below them for supporting them.
These shafts are screw threaded at the upper ends, and screw through
strong stud C projecting from the frame, by which and the screws the
said frame is supported on the bearings of the axle C¹ where the wheels C
are down upon the ground for the purpose, and by which and the
bearings the axle and the wheels C are in turn suspended from the
frame when raised out of action. For effecting this shifting. of the
wheels C to assume the load or to deliver it again to the other wheels
the screw shafts C¹ are provided with two bevel pinions C and C", one
above the pinion C and the other below, both feathered to the screw
shafts, and capable of sliding up and down for gearing with the pinion Co
or not. They are mounted in a bent plate C₁ arranged on vertical
extension of the extension C³ of the bearings C2 to slide up and down, so
that either pinion may be geared with pinion Co, the other being discon-
nected. For shifting the plates C¹ they are connected to arms C¹ of a
shaft C (or it may be the ends of the said shaft suitably bent for the
purpose), mounted so as to oscillate freely in the ends of arms C¹
attached to the extension C* of the bearings C. The shaft C is provided
with a shifting bar C" by which it may be oscillated to shift the plate C¹²

page_text: to gear either of the pinions with the pinion C, or adjust them so that
neither will gear with them. One of the screw shafts has a right-
hand thread and the other a left-hand, so that gearing with the axle
and screwing into their respective studs C they will move in the same
direction.
The operation of this apparatus for raising or lowering the wheels C
is as follows:-The clutches for working the chains G being brouglit
together, and motion being imparted to the wheels C and the axles C',
which we will suppose it is designed to move down upon the ground to
take the load, the attendant will move the bar C in the right direction
(which may be supposed to be from the boiler) to gear the screws so that
they will be screwed down. This will bring the lower pinion C³ up into
gear with the pinion C6, and the wheels C will be carried downward; also
the arms C, shaft C, and shifting bar C 17 along with them, until a pin C¹8
on the bar C" comes in contact with a cam plate C on the frame, which
will shift the bar C" backward enough to disconnect the wheels C" and
throw the shaft C7 out of gear. In the meantime the attendant will shift
the clutches of the main driving wheels so as to disconnect them, and
they will be raised above the ground, so that the load will be supported
on the others. The pin C¹s and the cam plate will be arranged relatively
to each other, so that the frame shall be raised as high as required on
the wheels C before the bar is shifted. For shifting the load back from
the wheels C to the wheels B the attendant will move the bar C" in the
other direction, say towards the boiler, bringing the upper wheels in
gear with the pinion C, by which the screw shafts will be turned in the
direction to raise the wheels until a pin C2 comes in contact with the
under side of the cam plate C, and throws the bar back to the middle
position. While this is taken place the attendant will again gear the
large wheels with the engines by means of the clutches. If it be
designed to effect these changes when the carriage is running backward,
when the motion of the pinion C would be reversed, and to trip the
bar C by the cam plate C the cam plate should be arranged so that it
may be shifted to the opposite inclination, that is to say, to the dotted
line . To obtain the universal motion required for the axle of the
guiding wheels D, I provide the axle D¹ at the centre with a disc or
central enlargement D2 above and below the shaft of the same thickness
to fit it on to centres D³ to oscillate vertically within a slotted enlarge-

page_text: ment D' of a vertical spindle D³ passing up through a support D, D',
attached to the frame or to the boiler, which is permanently connected
to the frame, and down through a brace D' crotched at the upper end,
and hinged to the frame at D°. Between the bottom of the support Do
and the top of the enlargement D' of the spindle is placed an india-
rubber or other spring D. The upper end of the spindle is provided
with a nut to prevent too free action of the spring. A crotched
tongue D is connected by the side of the crotched part to the axle near
cach wheel, and at the swinging end to a toothed segmental riin D¹²
fitted in a case formed partly by the curved front end of the frame and
partly by a curved plate D¹³ suspended from the frame, so that it may
slide back and forth in a circular path; and this segmental wheel is
worked for steering the carriage by a pinion D4, shaft D₁, pulley D¹º,
belt D, and a winding shaft D1, the latter mounted on the boiler near
the front part in convenient reach of the attendant, and provided with
a hand wheel for turning it. The belt passes on opposite sides of the
steam dome, and winds on a pulley or roller at one side while it winds off
a similar roller on the othe side. It will be seen that this arrangement
of the guiding axle and the guiding apparatus permits the axle to turn
freely in any direction that may be required by the most uneven road,
while it furnishes a very strong and reliable support for it; also that it
will work freely and uniformly, no matter what may be the position of
the axle, and also that the oscillation of the axle will not cramp the
frame or interfere in any way with the driving wheels.
I prefer to construct the frame mainly of one or more bars forming the
sides and ends made from strips of sheet metal or boiler plate bent into
the U form represented in cross section in Figure 7 and inverted, also
connected at the edges at suitable intervals by the cross stays K. secured
by rivets or bolts K¹. I propose to bend these bars at the ends on truc
circles or nearly so, and connect the opposite sides by transverse bars. The
housings may be cast in the form shown in the plan view of the bottom,
Figure 3, with side plates a to fit the outsides of the bar A and joined
below the bar by the cross plates b, which form
the boxes and strengthen the sides laterally.
slipped on the bars before they are bent to form
bar A, which may be made in two parts and
centre of the sides, is joined together. This construction of the frame
the bearing surfaces for
The housings may be
the ends, or before the
jointed together at the

page_text: and housings affords the greatest possible strength and least weight,
and makes besides a most convenient form for the attachment of the
boiler and other parts.
The improvement in the construction of the wheels consists in the
attachment of the two rows of socketted cups or ferrule M., by rivetting
or otherwise, to the inner face of a broad thin metal rim, so that the
spokes may be fitted into them at the other ends, and project obliquely
from each side across the vertical plane of the centre of the wheel; alsó
in the application to the spokes at the other ends of the nuts N to screw
against the hubs by which the arms may be kept at all times in any
required degree of tension, and the wheels will be very firmly braced
laterally.
I propose to make the water tank F of thin sheet metal about as deep
as the diameter of the boiler with a plane side at O' to be attached to
the end of the boiler, the said tank forming a prolongation of the same
to the end of the frame, where it is curved to correspond with the curved
end of the frame and is supported thereon by the bracket O2 resting on
the top of the frame and bolted to it. The plane end O¹ of the water tank
is provided with a circular flange O³, indicated by dotted lines in Figure 2,
fitting into the end of the boiler shell, and forms a means of securing the
tank and boiler together by bolts O* tapped through the shell into the
flange, to be removed for the attachment of the tank when access to
the flue space at that end of the boiler is required. It will be seen that
the wall of the end O' of the tank forms the end wall of the boiler
against which the caloric current impinges when passing from the lower
set of flucs e, seen in Figure 2, to the upper set fin the space behind the
dividing plate g, Figure 2, forming a combustion chamber which I
propose to employ for the better combustion of the
in a great measure unconsumed in continuous flues.
taken of this combustion chamber to introduce here a fresh supply of
oxygen by forcing into it a current of air to aid combustion of the gases.
This arrangement of the boiler and tank utilizes the heat which would be
given off to the atmosphere at the end, in raising the temperature of the
feed water, and as a further means of heating the water and of utilizing
the waste heat I propose to exhaust the steam or a part thereof into the
tank to raise the heat of the water therein, and be condensed as much as
possible to save it for repeated use, also to form a means to reduce the
noise of the exhaust steam.
gases
which
pass
off
Advantage may be

page_text: I propose to arrange a pipe to conduct a small jet of dry steam from
the dome to the front for discharge into the fire space to promote com-
bustion, and in doing so I prefer to coil the pipe around the opening for
the door inside, and provide it with small perforations to distribute the
supply. It is obvious that the improved mode of applying the power 5
and shifting from one set of driving wheels to another, as herein-
before described, is applicable alike to driving street carriages or to
locomotives on steam roads. It is also obvious that the second set of.
wheels which I employ add to the complete machine superior facilities
for use as a portable engine, as either set of the driving wheels may be 1
employed for working the driving belts while the other set support
the machine, the different sets affording different speeds for different
purposes.
Having described the nature of the said Invention, and the manner of
performing the same, I declare that what I claim as the Invention to be 1
protected by the herein-before in part recited Letters Patent is,-
1st. The driving wheels fitted to work loosely on the driving shaft, to
which the driving mechanism is positively connected and provided with
friction clutches for operation, substantially in the manner described.
2ndly. The employment with the main driving wheels of a traction 2
engine fitted on the driving shaft either for transmitting the power or
not of a secondary set geared for a different speed, the two sets arranged
for shifting the transmission of the power from the one set to the other,
substantially in the manner described.
3rdly. Providing a traction engine with one or more pairs of auxiliary 2
supporting wheels made vertically adjustable, so that the weight of the
machine may be thrown upon or taken from the said wheels, substantially
as described.
4thly. So constructing the machine that the driving power of the engine
may be applied either to the main driving wheels or to the auxiliary 3
supporting wheels, substantially as described.
5tbly. The arrangement of the bearing surfaces of the friction clutches
on an angle of seven to ten degrees of inclination with the line parallel
with the shaft whereon they work, substantially as specified.
6thly. The construction of the clutches in two parts and the connection 3
of the same by the one screwing into the outer and by a set screw,
substantially as specified.

page_text: L
7thly. The crotched arms for working the sliding parts of the clutches
arranged to move on a support H³ in a line parallel with the axle F2 and
connected to the levers H³ and I* substantially as specified.
8thly. The combination with the pairs of clutch shifting levers of the
right and left screw threaded shafts I, I¹; or I³ and I arranged for joint
and simultaneous or independent action, substantially as specified.
9thly. The connection of the axle of the secondary set of driving
wheels to the frame by means of the extensions C³ of the bearings, the
screw threaded rods C³, and screw threaded studs C³, substantially as
specified.
10thly. The combination with the axle C' and the rods C" of the
pinions Co, C, and C, and the shifting support C for the pinions on
the rods C', substantially as specified.
11thly. The combination with the shifting supports C12 of the oscillating
shaft Cs and the shifting bar C", the said shaft C¹³ being supported on
the bearing C² to rise and fall with them, substantially as specified.
12thly. The combination with the shifting bar C" and the shifting
plate C reversing pinions, and the screw rods C of a cam plate for
automatically disconnecting the reversing pinions, substantially as
specified.
.
13thly. The axle D' provided with the disc D2 centered in the slotted
spindle D³, the latter mounted in the support Dº, D', and the brace D³,
substantially as specified.
14thly. The combination with the axle D¹ and the crotched tongue
of the segmental toothed rim arranged to slide back and forth in a
circular track on the frame and operated by the pinion D and shaft D¹³,
substantially as specified.
15thly. The combination with the shaft D1 and pulley thereon of the
belt D and the hand winding shaft D18, the latter being arranged for
carrying the belt on each side of the steam domes, substantially as
specified.
16thly. The frame A composed of the inverted U formed bars. united
at the edges by the stays K, substantially as specified.
17thly. The housings provided with the side plates a united by the
transverse plates 6, the latter forming the bearing surfaces for the journal
boxes, and arranged for the connection of the housings with the bars A
by sliding thereon, substantially, as specified.

page_text: 18thly. The combination with the spokes, rims, and the hubs of the
wheels of the cups M and adjusting nuts, substantially as specified.
19thly. The arrangement of the water tank and the boiler whereby
the end wall of the tank forms the end wall of the boiler, substantially
as specified.
20thly. The detachable connection of the water tank to the boiler by
means of the circular flange O³ and the bolts O*, and to the frame by the
bracket O, substantially as specified.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal; this Third day of May, in the
year of our Lord One thousand eight hundred and seventy.
Witness,
W. G. E. SwINNOCK,
53, Chancery Lane,
London.
A. M. CLARK: (L.S.)