IMPROVE MENTS IN MACHINERY OR APPARATUS FOR DREDGING OR EXCAVATING, AND FOR DRIVING PILES
Year: 1859

page_text: LETTERS PATENT to Christopher Pottinger, of Anstruther, in the County
of Fife, North Britain, Boat Builder, for the Invention of "IMPROVE
MENTS IN MACHINERY OR APPARATUS FOR DREDGING OR EXCAVATING, AND FOR
DRIVING PILES."
Sealed the 20th December 1859, and dated the 16th July 1859.
PROVISIONAL SPECIFICATION left by the said Christopher Pottinger at
the Office of the Commissioners of Patents, with his Petition, on the
1. th July 1859.
I, CHRISTOPHER POTTINGER, of Anstruther, in the County of Fife, North
Britain, Boat Builder, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DREDGING OR EXCAVATING, AND
FOR DRIVING PILES," to be as follows, that is to say: -
This Invention relates more particularly to dredging or excavating
machinery, such as is used for deepening rivers and harbours, but it is also
applicable for other work of a generally similar character, as well as for
driving piles for foundations, and other purposes. The boat or foundation on
which the machinery is carried consists of a flat-bottomed punt or platform
with sloping ends. In or near the centre of this punt, the steam engine, by
preference of the vertical cylinder direct-acting class, is placed. This engine
actuates a short horizontal transverse shaft, which is geared to a second shaft

page_text: with a tumbler working an endless chain of dredging buckets inclined
downwards and passed through a slot or open cut in the extreme end of
the punt. The outer bottom end of this chain of buckets works over an
adjustable tumbler shaft in the usual way. In this way, as the chain of
buckets works, the buckets dig up or dredge the mud or earth and carry it
up their incline, and deliver it at or near the centre of the punt or platform.
The same train of gearing also drives a short longitudinally disposed
tumbler for actuating a transverse endless chain of waggons or carriers.
The frame or trough of this chain of waggons is disposed at right angles
to the chain of excavating buckets and the outer end of the chain works over
a tumbler, as in the former case, the chain being extended far out beyond the
edge or side of the punt. In this way, the operation of the dredger is such
that each dredging bucket delivers its contents into one of the transverse
carrying waggons, and thus the earth or excavated matter is carried clear
away over the side of the punt and delivered upon the bank of the river or
dock without the intervention of any Hoating punts.
This machinery answers also for dredging or excavating in situations
wholly dry, as the platform carrying it then rests firmly on the soil. The
dredging end can also be fitted with additional endless chain carriers or
waggons worked from the end tumbler, and so arranged as to receive earth
from attendants, who deposit it in the waggons for conveyance to the chain
of dredging buckets, which then act simply as carriers. In this way, the
line of buckets can be made to operate over an extended surface without
shifting. On the same punt there is fitted up in connection with the
actuating steam-engine a lever pile-driver; this consists of an over-head
lever, centred at one end upon a fixed stud in the framing and attached by
a connecting rod near its centre to the engine. The outer free end of the
lever carries the pile-driving head, extending well over the edge of the punt
and thus as the engine works, both dredging and pile-driving may be most
effectively carried on. This can also be used for extracting piles.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Christopher Pottinger in the Great Seal Patent Office on
the 16th January 1860.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of July, in the year of our Lord One
thousand eight hundred and fifty-nine, in the twenty-third year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Christopher Pottinger, Her special license that I, the said Christopher
Pottinger, my executors, administrators, and assigns, or such others as
I, the said Christopher Pottinger, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and lawfully
might inake, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DREDGING OR EXCAVATING,
AND FOR DRIVING PILES," upon the condition (amongst others) that I, the said
Christopher Pottinger, by an instrument in writing under my hand and seal,
should particularly describe and ascertain the nature of the said Invention,
and in wliat manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next aud
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Christopher Pottinger, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say :-
My said Invention relates more particularly to dredging or excavating
machinery, such as is used for deepening rivers and harbours, but it is also
applicable for other work of a generally similar character, as well as for
driving piles for foundations and other purposes. The boat or foundation on
which the machinery is carried consists of a flat-bottomed punt or platform
with sloping ends. In or near the centre of this punt, the steam engine, by
preference of the vertical cylinder direct-acting class, is placed. This engine
actuates a short horizontal transverse shaft, which is geared to a second shaft
with a tumbler working an endless chain of dredging buckets inclined down.
wards, and passed through a slot or open cut in the extreme end of the punt.
The outer bottom end of this chain of buckets works over an adjustable
tumbler shaft in the usual way. In this way, as the chain of buckets works,
the buckets dig up or dredge the mud or earth, and carry it up their incline,
and deliver it at or near the centre of the punt or platform. The same train
of gearing also drives a short longitudinally-disposed tumbler for actuating a
transverse endless chain of waggons or carriers. The frame or trough of this

page_text: chain of waggons is disposed at right angles to the chain of excavating
buckets, and the outer end of the chain works over a tumbler as in the former
case, the chain being extended far out beyond the edge or side of the punt.
In this way the operation of the dredger is such, that each dredging bucket
delivers its contents into one of the transverse carrying waggons, and thus the
earth or excavated matter is carried clear away over the side of the punt and
delivered upon
the bank of the river or dock without the intervention of any
floating punts.
This machinery answers also for dredging or excavating in situations wholly
dry, as the platform carrying it then rests firmly on the soil. The dredging
end can also be fitted with additional endless chain carriers or waggons worked
from the end tumbler, and so arranged as to receive earth from attendants,
who deposit it in the waggons for conveyance to the chain of dredging
buckets, which then act simply as carriers. In this way the line of buckets
can be made to operate over an extended surface without shifting. On the
same punt there is fitted up, in connection with the actuating steam engine,
a lever pile driver. This consists of an over-head lever, centred at one end
upon a fixed stud in the framing, and attached by a connecting rod near its
centre to the engine. The outer free end of the lever carries the pile-driving
head, extending well over the edge of the punt, and thus, as the engine works,
both dredging and pile driving may be most effectively carried on.
This can
also be used for extracting piles.
And in order that my said Invention of "Improvements in Machinery or
Apparatus for Dredging or Excavating, and for Driving Piles," may be pro-
perly understood I shall now proceed to describe the several Figures on the
two explanatory Sheets of Drawings, which I have hereunto appended for
the purpose of showing certain modifications under which my improvements
may be judiciously carried out in practice, that is to say,-
Figure 1 on Sheet 1 of the accompanying Drawings is a partially sec-
tional elevation or lougitudinal view of one modification of my improved
dredging or excavating and pile-driving machine; Figure 2 on the same
Sheet is a corresponding plan of the same; and Figures 3 and 4 are an
elevation and plan of a portion of the details used in conveying excavated
earth, and elevating it to anembankment or level above the place of excavation.
Figure 1, on Sheet 2, of the accompanying Drawings is a transverse
vertical section of the machine looking towards the stern of the punt or barge
in which the machinery is contained, and longitudinally on the endless chain
of waggons or carriers which carry away the dredged or excavated materials
to the vessel or receptacle prepared for the same. Figure 2 on the same

page_text: Sheet is a similar transverse section but taken through the opposite or after
end of the barge and showing the arrangement and position of the pile-driving
machinery as applied to the construction of circular caissons or towers adapted
for forming artificial harbours or breakwaters. Figures 3 and 4, represent an
elevation and plan of the mechanical arrangement for filling the interior of the
caissons with the dredged soil, the operations of dredging and filling being
carried on simultaneously. The whole of the machinery or apparatus is
arranged and carried in a broad flat-bottomed barge or dredging vessel A, on
the starboard side of which are arranged the boilers B, placed fore and aft and
with the furnace mouths opposite to each other as shown in the sectional view
Figure 1, on Sheet 1, of the accompanying Drawings. The furnaces of the
boilers are arranged in an internal tube, the smoke and products of combustion
pass off into two lateral flues which return towards the front of the boiler and
thence enter the duplex or union Blue which forms the lower end of the funnel C.
At or about the centre of the vessel A, is arranged the engine which actuates
the dredging machinery and the apparatus for slowly propelling the vessel
forward as the dredging operation proceeds. The cylinders D, of the engine
are of the trunk class, they are arranged in the centre of the vessel and at
right angles to its length, by means of the rods E, they are connected direct to
the crank shaft F which extends across and is carried in pedestal bearings
fitted on the upper part of the framing G. Between the cylinders D, are
arranged the valve chests, the slide valves of which are actuated direct from
the crank shaft, and on the left-hand extremity of the shaft F', is a fly wheel H,
furnished with a crank the pin of which is connected by means of the rod I
to the cross-head J, which works the air pumps. To the opposite or right-
hand end of the crank shaft F, is keyed the fly wheel K, this wheel is made
with a large boss on which is fitted the pinion L, this pinion is tightened up by
the nut on the extremity of the shaft F. This arrangement of the pinion on
the shaft is intended to secure the moving parts of the machinery from injury
should any extraordinary impediment occur in the dredging operation. This
is provided for by tightening up the pinion on the shaft L, sufficiently to drive
its connected gearing, but should an obstacle occur to prevent the ascent of
the dredging buckets, the pinion L then slips round on the boss of the fly
wheel K, and so prevents any injury to the gearing. The periphery of the
pinion L, is just level with an opening cnt in the deck M, of the vessel on
which is erected a substantial timber framing N, carrying the gearing and
parts connected with the upper end of the dredging apparatus, and the inner
end of the endless train of waggons. There is also a secondary framing O,
which extends from stem to stern of the vessel A, and out over its sides, this

page_text: framing serves to support the outer portion of the dredging apparatus, the
train fo waggons, as well as the pile-driving engine and apparatus. The pinion
L gears with a spur wheel P which is keyed to a horizontal shaft Q, the
pedestal bearings of which are bolted to short horizontal beams of the
framing N.
The shaft Q, also carries a pinion R, which gears with
the wheel S on the shaft T; this shaft extends outwards to the starboard side
of the vessel, and its bearings are carried on transverse beams fitted on the
framing N, and between two of the uprights of the framing O. The inner
extremity of the shaft T has keyed to it the compound spur and bevel
wheel U; the spur wheel gears with the wheel V on the shaft W, this wheel
gives motion to the endless chain of buckets ofthe dredging apparatus, and it is
fitted to slide to and fro on a feather formed on the shaft W, so that by means
of the coupling X it may be readily thrown out of or into gear with the
wheel U. The bearings of the shaft W are carried on the upper beams of the
framing N, and inside the wheel V there is fitted on the shaft a square barrel
or chain wheel Y,round which the endless chain of buckets Z traverse. These
buckets are attached to the endless chain a, the links of which are made equal
in length to the breadth of the sides of the barrels round which they travel.
The links of the chain are arranged in a double series parallel to each other,
alternated with single links, and the lugs on each bucket are fastened to the
single links by means of bolts or rivets. The chain is extended outwards by
means of the frame b, which consists of parallel side pieces of timber fitted
with deep caps or end pieces of cast or wrougt iron at the top and outer
ends, and strengthened by tie rods which pass through or are bolted to pro-
jecting brackets attached to the side pieces of the frame. At the outer end of
the frame b is fitted a square barrel or chain wheel c, round which the chain a
traverses, the barrel c corresponding to the upper barrel Y. The upwardly
projecting brackets on the frame 6 have jointed to them the shackle e,
which is passed over the hook of the block f, which, by means of the chain
and the overhead block g, serve to raise or lower the dredging apparatus as
required. This raising or lowering of the dredger may be effected by carrying
the chain tackle round the barrel of a steam winch arranged on the deck at
the fore part of the vessel; or if preferred, the work may be done by means
of an ordinary windlass. As the dredging apparatus removes the soil from the
bed of the river, harbour, or other place where the machine is used, a slow
progressive movement is imparted to the machine, so that the buckets are
continually working forward on fresh ground. This is effected by means of
poles arranged in angular positions, and actuated by the steam engine; these
propelling poles extend to the bed of the river or harbour, and being caused to

page_text: press alternately against the soil, the dredging vessel is slowly urged forward.
On the face of the compound spur and bevel wheel U is fitted a crank, to the
pin of which is connected one end of the connecting rod, the other extremity
of which is jointed to the pendent lever i, which is fast to the horizontal
shaft j, the bearings of which are bolted to the faces of two horizontal
beams & secured to two of the uprights of the framing o. To each extremnity
of the shaft is fitted a two-armed lever ; in the ends of these levers are
laterally projecting studs, which serve to connect them to the caps on the
upper ends of the propelling poles m; these are long spars of timber extending
downwards in an angular direction on each side of the vessel A. The pro-
pelling poles m are fitted at the lower ends with cast-iron shoes n, which
present a broad surface to the soil forming the bed of the river or harbour.
The crank on the bevel wheel U imparts a reciprocatory movement to
the shaft j, which causes the levers to oscillate upon their centres; this
motion forces one of the propelling poles on each side of the vesse! down to the
bed of the river or harbour. The resistance offered to the propelling poles causes
the dredging vessel to move forward to a certain extent, simultaneously with
the pushing motion of one pair of propellers the others are withdrawn, and at
the backward motion of the connecting rod they are in like manner thrust
down as the others are withdrawn. The connecting rod h may be fitted to
give a greater or less amount of throw to the levers, and consequently to the
propelling poles by fitting the crank pin in a slot in one of the arms of the
bevel wheel U. In cases where the nature of the soil in the bed of the river
or harbour does not admit of using this mode of propelling the vessel forward,
the ordinary means may be adopted. The soil dredged from the bed of the
river or harbour is delivered by the buckets Z into an endless chain or series
of waggons or carriers, which convey the contents either on shore or to any
point within the extent of the endless chain of waggons. The bevel wheel of the
compound spur and bevel wheelU gears with a corresponding wheeloarranged
on a horizontal shaft p,this wheel is furnished with a coupling p', to admit of its
being put into or out of gear with the wheel U. On the shaft of the wheel o
is a square barrel corresponding to the barrels Y and c of the dredging
apparatus, round this barrel the endless chain q traverses, this chain is made
up of duplex parallel links with intermediate single links, as described in
reference to the chain a of the dredger; to the links of the chain are attached
the small carriers or waggons r, these waggons are furnished with. small
wheels or rollers which run on the angle iron rails s, the lower rails serving to
prevent the line of waggons from swaying downwards when passing along
underneath. The chain 9 is extended outwards and passed round the barrel t

page_text: fitted at the extremity of the overhanging frame u, which is generally similar
in its construction to that of the frame of the dredging apparatus. The two
side pieces of the frame are strengthened by tie rods which pass through
vertically arranged brackets bolted to the frame, which brackets serve also for
the attachment of the rails s. The central part of the frame z is connected
by a shackle to the block and chain tackle v,by means of which the elevation
of the frame may be altered as required, the chain may be conveniently
carried down to a barrel on the shaft T', so as to raise and lower the frame by
steam power. The inner end of the framo u is carried upon the shaftp, on
which it turns when moved up or down by the lifting tackle v, it is also stayed
laterally by the diverging stays w, the outer ends of which are fitted in cast-
iron caps secured to the side pieces of the frame, the inner ends of the stays
are jointed to bearings which are bolted down to cross beams carried on the
framing N. The arrangement of the stays w does not in any way interfere
with the vertical traverse of the frame and its connected parts, at the
same it prevents any derangement arising from lateral strain. It is to
counterbalance the overhanging weight of the frame u, and the waggons that
the boilers are arranged fore and aft on the starboard side of the vessel A.
When the dredger and delivering apparatus are in operation, the buckets Z
discharge their contents in succession into the waggons as they traverse
beneath, and these carry the soil and discharge it on to the adjoining embank-
ment or elsewhere, as desired. This machine is also applicable to facilitat to
a great extent the operation of excavating docks and other similar places; one
modification of the arrangement for this purpose is delineated in Figures 3
and 4, on Sheet 1 of the accompanying Drawings, which represent in plan and
elevation the lower extremity of the chain of buckets Z, working in con-
junction with an endless train of waggons. In this arrangement the machine
is supposed to be floated into the partially excavated dock, or sufficiently near
it for the removal of the earth as it is excavated by the navigators. The lower
end of the bucket frame has connected to it the cast-iron frame a between
the cheeks of which the buckets Z pass in an upward direction. The shaft on
which the barrel c is fixed at the lower end of the frame b extends out beyond
the frame on one side, and to this overhanging part is keyed the hexagonal
chain wheel y, round which is passed the endless chain z. This chain is
passed round, and gives motion to a chain wheel 1, keyed to a horizontal
shaft 2 carried in the framing a; this shaft has also keyed to it a bevil
wheel 3, which gears with a corresponding wheel 4, forming the lower part
of the barrel 5, round which the train of waggons 6 traverse, the journals of
the barrel 5 being carried in footstep and collar bearings fitted in the

page_text: framing x. The waggons 6 are attached to the links of the chain 7, their
wheels traversing on the line of planks 8 laid down for both lines of waggons.
The endless chain 7 is extended along the line of the excavation, and carried
round a barrel 81, fitted in the framing 9; this portion of the apparatus is
carried upon the cruciform timber foundation 91. In this modification the
waggons 6 are shown as fixed to every fourth link of the chain 7, but the
number may be doubled if found desirable. The bottoms of the waggons are
hinged to the sides, and they are so arranged that the retaining catch which
holds the bottom up is pushed aside by a stop on the barrel 5, so as to allow
the contents to drop into the buckets Z. As the waggons pass round the
barrel, the bottom of each waggon is raised by passing over an incline which
shuts the catch, the waggons are thus again in readiness to receive anotherload.
As the navigators fill the line of waggons proceeding towards the barrel 5, the
waggons successively discharge their contents into the chain of buckets Z,
which carry the earth upwards to the waggons r, by means of which it is
conveyed away to the adjoining embankment or elsewhere. In this way the
wheeling away of the earth is dispensed with, and manual labour in works of
this kind is greatly enonomised.
In Sheet 2 of the accompanying Drawings is shown more particularly
the application of this machine to the purposes of pile driving. The framing
in which the pile driving machinery is arranged is parallel and contiguous
to the great transverse framing carrying the waggons and their appur-
tenances, and it forms a portion of the framing O overhanging the starboard
side of the vessel A. At this part there are four vertical pillars or uprights 10,
which are arranged in pairs parallel to each other, the contiguous faces
being faced with iron, so as to form guides in which the pile driving
machinery traverses up and down. To these pillars 10 is fitted the cast-
iron platform 11, on which is arranged the engine 12, which is by
preference of the trunk class; the steam is conveyed to the valve chest from
one of the boilers B, by means of a telescopic or jointed steam pipe connected
to the ingress pipe 12'. The lower end of the connecting rod is jointed in the
usual manner to the interior of the trunk or hollow piston rod, and its upper
extremity to the weighted lever 13, which forms the pile driver. This leverisa
malleable iron beam extending towards the centre of the vessel, and centred on a
stud fitted in the inwardly projecting part of the framing 11. To the outer end
of the lever 13 is bolted the heavy mass of metal 14, which forms the pile
driver; this is shaped somewhat in the form of a hammer head. The outer
extremity of the platform 11, has an aperture formed in it which is large
enough to receive the upper extremity of the pile. In Figure 2, on Sheet 2,

page_text: of the accompanying Drawings, is shown a caisson in the course of formation
The platform 11, carrying the engine and pile driver is hauled up either by
steam power or manual labour to the upper part of the guide pillars 10, and
the aperture in the platform is brought over the upper end of the pile to be
driven. Upon the steam being admitted to the cylinder the upward motion
of the piston raises the pile driver 14, the steam is allowed to escape suddenly,
so that the hammer falls with great force upon the head of the pile. During
the operation of driving the pile the lifting tackle of the platform 11, and its
connected parts is slackened, so that a considerable portion of their weight is
thrown upon the pile, which assists its downward course. The valve gearing
is connected to the lever 13, and is so arranged that on the pile driver
reaching the limit of its upward traverse the exhaust is opened, and the steam
escapes suddenly, and on the pile driver giving the blow the induction port is
opened for the admission of the steam, so that the blows follow each other
in rapid succession. The platform 11, with the engine and pile driver, being
upheld by the outer end of the platform resting upon the pile, the whole
gradually descends as the pile is driven, and is hauled up to the top, when
the operation has to be repeated. The block and chain tackle for effecting
the lifting of the platform 11, is attached to the cross beam 15, supported
on the outer extremities of the framing O, the lifting being effected by the
assistance of the steam engine, or if preferred by the ordinary hand windlass.
This machine is also applicable to the filling of caissons or other similar
structures intended for the formation of artificial harbours, breakwaters, the
foundations of lighthouses, and other structures of a generally similar nature.
In Figures 3 and 4, on Sheet 2, of the accompanying Drawings, is shown
in elevation and plan one mode of arranging the machinery, so as to fill the
caisson in a uniform manner, and simultaneously with the dredging operation
and consequent deepening of the water around the exterior of the caisson.
Extending across the top of the caisson 16, are laid the beams 17, which form
a foundation of a cruciform figure, across the centre of w! ich is laid a block
supporting the pillar 18. This pillar has fitted to it a loose swivelling frame19,
which is of a T-shaped figure, as is shown by the elevation delineated to the
right of Figure 3 on Sheet 2 of the accompanying Drawings. To the vertical
pillars 18, in the centre of the casting 19, is fixed a lantern or chain wheel 20,
and parallel with this wheel are two pulleys 21, carried on pins passing through
the outer and inner parts of the frame 19. Over the pulleys 21, the side pieces
of the rectangular frame 22 pass, the extremities of which are bolted to the
end of the frameu, carrying the endless series of waggons 7. To the lower part
of the frame u, is attached a chain 23, which is carried round the wheel 20,

page_text: and then secured to an eye bolted to the frame 22. With this arrangement
as the dredging vessel traverses round the exterior of the caisson,the soil as it
is lifted is delivered into the interior of the caisson. And as the vessel moves
round in one direction, the chain 23 winds the frame u gradually inwards
towards the centre of the caisson, the waggons meanwhile depositing the soil
uniformly from the inner face of the caisson to the centre. Upon causing the
vessel to traverse in the opposite direction around the caisson, the end of the
waggon frame u moves outwards in the direction of the periphery of the
caisson. This alternate to-and-fro movement of tho waggon frame u in con-
junction with its circular traverse, causes the soil to be discharged into the
interior of the caisson in uniform layers of strata. In this manner caissons
and other generally similar hollow works may be filled up in a rapid and
effective manner, and without involving the use of manual labour. The
machine may also be rendered available for extracting or withdrawing piles
from the bed of the river or harbour. A chain is attached to the pile, which
chain works over the pulley 24, and is carried downwards, as is indicated by
the dotted lines 25, to the barrel 26, arranged on the horizontal shaft T. The
other portions of the machinery being thrown out of gear the full power of
the engine may be directed to the operation of drawing up the piles from
the bed of the river or harbour. There are also other useful purposes to which
my improved dredging and excavating machine may be advantageously
applied in the formation of river and marine works involving the displace-
ment and arrangement of large masses of materials.
Having now described and particularly ascertained the nature of my said
Invention,and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider novel and original,
and therefore claim as the Invention secured to me by the herein-before in
part recited Letters Patent, is,-
First, the general arrangement arrangement and construction of machinery
or apparatus suitable for dredging or excavating and pile driving as herein-
before described and illustrated in the accompanying Drawings.
Second, the system or mode of combining in one machine the dredging and
soil delivery apparatus, together with the pile driving machine as herein-
before described and shown in the accompanying Drawings.
Third, the arrangement and construction of the dredging machinery in
conjunction with the endless chain of waggons or carriers for conveying the
dredged material either on shore or to any receptacle within the range
of the delivery apparatus, as herein-before described and delineated in the
accompanying Drawings.

page_text: Fourth, the system or mode of forming docks or other extensive waterside
excavations with the aid of the machinery herein-before described and shown
in Sheet 1 of the accompanying Drawings, in which the earth or excavated
material is conveyed away by an endless train of self-acting waggons and lifted
on to the embankment or other distant point by means of the elevator aud
second train of waggons.
Fifth, the system or mode of driving piles and performing other similar
work by means of the mechanical arrangement herein-before described and
shown in the accompanying Drawings, or any mere equivalent therefor. _
Sixth, the system or mode of filling up caissons or other similar hollow
works with the material dredged from the exterior of the caisson, both
operations of dredging and filling up being carried on simultaneously, and by
means of the machinery or apparatus herein-before described and shown in
the accompanying Drawings.
In witness whereof, I, the said Christopher Pottinger, have hereunto set
my hand and seal, this Fourteenth day of January, One thousand
eight hundred and sixty.
CHRISTOPHER POTTINGER. (L.S.)